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Sample records for calcium based correlation

  1. Serum Calcium Increase Correlates With Worsening of Lipid Profile

    Science.gov (United States)

    Gallo, Luigia; Faniello, Maria C.; Canino, Giovanni; Tripolino, Cesare; Gnasso, Agostino; Cuda, Giovanni; Costanzo, Francesco S.; Irace, Concetta

    2016-01-01

    Abstract Despite the well-documented role of calcium in cell metabolism, its role in the development of cardiovascular disease is still under heavy debate. Several studies suggest that calcium supplementation might be associated with an increased risk of coronary heart disease, whereas others underline a significant effect on lowering high blood pressure and hyperlipidemia. The purpose of this study was to investigate, in a large nonselected cohort from South Italy, if serum calcium levels correlate with lipid values and can therefore be linked to higher individual cardiovascular risk. Eight-thousand-six-hundred-ten outpatients addressed to the Laboratory of Clinical Biochemistry, University of Magna Græcia, Catanzaro, Italy from January 2012 to December 2013 for routine blood tests, were enrolled in the study. Total HDL-, LDL- and non-HDL colesterol, triglycerides, and calcium were determined with standard methods. We observed a significant association between total cholesterol, LDL-cholesterol, HDL-cholesterol, non-HDL cholesterol, triglycerides, and serum calcium in men and postmenopause women. Interestingly, in premenopause women, we only found a direct correlation between serum calcium, total cholesterol, and HDL-cholesterol. Calcium significantly increased while increasing total cholesterol and triglycerides in men and postmenopause women. Our results confirm that progressive increase of serum calcium level correlates with worsening of lipid profile in our study population. Therefore, we suggest that a greater caution should be used in calcium supplement prescription particularly in men and women undergoing menopause, in which an increase of serum lipids is already known to be associated with a higher cardiovascular risk. PMID:26937904

  2. Correlation between calcium carbonate content and emission characteristics of incense.

    Science.gov (United States)

    Yang, Chi-Ru; Lin, Ta-Chang; Chang, Feng-Hsiang

    2006-12-01

    In Taiwan and China, calcium carbonate is commonly added as a filler during incense production to lower the cost. This study has found an unexpected benefit for this practice: it reduces particulate emission. Nine types of the popular incense on the local market were chosen for this study. The calcium content in raw material incense was analyzed by inductively coupled plasma atomic emission spectrometry, followed by X-ray diffraction (XRD) spectroscopy. The correlation between the calcium content and emission characteristics of incense was investigated. The calcium content varied from 1.8 to 60 mg/g (incense burned) among those nine different types of incense. Very little calcium (incense. Instead, most calcium was artificially added in the form of CaCO3 during manufacturing. The combustion characteristics, including burning rate, emission factors of particulate, ash, and solid-phase polycyclic aromatic hydrocarbons (S-PAHs), varied significantly among the nine types of incense. Incense containing 2% calcium would emit 30% less S-PAHs, compared with those with little (incense by approximately 50%.

  3. Mercury Control with Calcium-Based Sorbents and Oxidizing Agents

    Energy Technology Data Exchange (ETDEWEB)

    Thomas K. Gale

    2005-07-01

    This Final Report contains the test descriptions, results, analysis, correlations, theoretical descriptions, and model derivations produced from many different investigations performed on a project funded by the U.S. Department of Energy, to investigate calcium-based sorbents and injection of oxidizing agents for the removal of mercury. Among the technologies were (a) calcium-based sorbents in general, (b) oxidant-additive sorbents developed originally at the EPA, and (c) optimized calcium/carbon synergism for mercury-removal enhancement. In addition, (d) sodium-tetrasulfide injection was found to effectively capture both forms of mercury across baghouses and ESPs, and has since been demonstrated at a slipstream treating PRB coal. It has been shown that sodium-tetrasulfide had little impact on the foam index of PRB flyash, which may indicate that sodium-tetrasulfide injection could be used at power plants without affecting flyash sales. Another technology, (e) coal blending, was shown to be an effective means of increasing mercury removal, by optimizing the concentration of calcium and carbon in the flyash. In addition to the investigation and validation of multiple mercury-control technologies (a through e above), important fundamental mechanism governing mercury kinetics in flue gas were elucidated. For example, it was shown, for the range of chlorine and unburned-carbon (UBC) concentrations in coal-fired utilities, that chlorine has much less effect on mercury oxidation and removal than UBC in the flyash. Unburned carbon enhances mercury oxidation in the flue gas by reacting with HCl to form chlorinated-carbon sites, which then react with elemental mercury to form mercuric chloride, which subsequently desorbs back into the flue gas. Calcium was found to enhance mercury removal by stabilizing the oxidized mercury formed on carbon surfaces. Finally, a model was developed to describe these mercury adsorption, desorption, oxidation, and removal mechanisms, including

  4. Ceramics based on calcium pyrophosphate nanopowders

    Directory of Open Access Journals (Sweden)

    Tatiana V. Safronova

    2013-03-01

    Full Text Available Present work is aimed at the fabrication of resorbable bioceramics based on calcium pyrophosphate (CPP from the synthesized powders of amorphous hydrated calcium pyrophosphate (AHCPP. Amorphous hydratedcalcium pyrophosphate in the form of nanopowders was precipitated from Ca(NO3 2 and (NH4 4P2O7 solutions at room temperature in the presence of PO3– ions. Crystalline CPP powder was fabricated from AHCPP by its thermal decomposition at 600 °C and consisted of β- and α- phase. Small particles, with the size less than 200 nm, were formed promoting sintering of the ceramic material. The final sample, sintered at 900 °C, exhibits microstructure with submicron grains, apparent density of 87% of theoretical density (TD and demonstrates tensile strength of 70 MPa.

  5. Cluster identification based on correlations

    Science.gov (United States)

    Schulman, L. S.

    2012-04-01

    The problem addressed is the identification of cooperating agents based on correlations created as a result of the joint action of these and other agents. A systematic method for using correlations beyond second moments is developed. The technique is applied to a didactic example, the identification of alphabet letters based on correlations among the pixels used in an image of the letter. As in this example, agents can belong to more than one cluster. Moreover, the identification scheme does not require that the patterns be known ahead of time.

  6. Calcium phosphate-based ceramic and composite materials for medicine

    International Nuclear Information System (INIS)

    The topical problems in chemistry and technology of materials based on calcium phosphates aimed at both the replacement of damaged bone tissue and its regeneration are discussed. Specific features of the synthesis of nanocrystalline powders and the fabrication of ceramic implants are described. Advances in the development of porous scaffolds from resorbable and osteoconductive calcium phosphates and of hybrid composites that form the basis of bone tissue engineering are considered.

  7. Evaluation of calcium ion, hydroxyl ion release and pH levels in various calcium hydroxide based intracanal medicaments: An in vitro study

    OpenAIRE

    Punit Fulzele; Sudhindra Baliga; Nilima Thosar; Debaprya Pradhan

    2011-01-01

    Aims: Evaluation of calcium ion and hydroxyl ion release and pH levels in various calcium hydroxide based intracanal medicaments. Objective: The purpose of this study was to evaluate calcium and hydroxyl ion release and pH levels of calcium hydroxide based products, namely, RC Cal, Metapex, calcium hydroxide with distilled water, along with the new gutta-percha points with calcium hydroxide. Materials and Methods: The materials were inserted in polyethylene tubes and immersed in deionized wat...

  8. Correlation of blood lead level with iron, zinc and calcium as well as neonatal neurobehavioral development

    Institute of Scientific and Technical Information of China (English)

    Shiguang Li; Guoping Wang; Shenghui Li; Xianguo Wu; Chunru Qi; Yingyi Liang

    2006-01-01

    BACKGROUND: Endothelial cell in brain of undeveloped fetus cannot inhibit entrance of lead so as to cause toxic effect. Over-accumulation of lead can cause toxic effect on children's growth and development, especially on development of nervous system. Lead in fetus body is mainly derived from its mother's; therefore, blood lead reflects the level of mother's lead.OBJECTIVE: To analyze the correlations among blood lead level, trace elements, mental development index (MDI) and psychomotor development index (PDI) of 3-month-old children. DESIGN: Contrast observation. SETTING: Maternity and Child Care Hospital, Shanxi Provincial Children Hospital. PARTICIPANTS: A total of 128 neonates with spontaneous delivery were provided by Shanxi Maternity and Child Care Hospital and Jiexiu Municipal Maternity and Child Care Hospital from September 2004 to January 2005. There were 76 boys and 52 girls. All subjects did not have history of ischemia and hypoxia during perinatal period and umbilical blood was accepted to be used in experiments. METHODS: ① Levels of iron, calcium and zinc in umbilical blood: 0.5 mL umbilical blood and 2 mL blood samples were selected from neonates to measure lead content with graphite-oven atom absorption spectrum and contents of iron, calcium and zinc in umbilical blood with atom absorption spectrum. ② Grouping: According to level of blood lead, neonates were divided into high-dosage lead group (blood lead ≥ 0.24 μmol/L) and low-dosage lead group (blood lead < 0.24 μmol/L). ③ Evaluation of neurobehavioral development: Neurobehavioral development of 3-month-old neonates was evaluated with Bayley scale, which was consisted of intelligence scale, motor scale and behavioral scale. Intelligence scale, which was expressed as intelligence development index, contained 163 items, such as adaptability, behavior, language, pilot activities, etc. Motor scale, which was expressed as mental motor development index, contained 81 items, such as vulgar

  9. Serum Calcium Increase Correlates With Worsening of Lipid Profile: An Observational Study on a Large Cohort From South Italy.

    Science.gov (United States)

    Gallo, Luigia; Faniello, Maria C; Canino, Giovanni; Tripolino, Cesare; Gnasso, Agostino; Cuda, Giovanni; Costanzo, Francesco S; Irace, Concetta

    2016-02-01

    Despite the well-documented role of calcium in cell metabolism, its role in the development of cardiovascular disease is still under heavy debate. Several studies suggest that calcium supplementation might be associated with an increased risk of coronary heart disease, whereas others underline a significant effect on lowering high blood pressure and hyperlipidemia. The purpose of this study was to investigate, in a large nonselected cohort from South Italy, if serum calcium levels correlate with lipid values and can therefore be linked to higher individual cardiovascular risk.Eight-thousand-six-hundred-ten outpatients addressed to the Laboratory of Clinical Biochemistry, University of Magna Græcia, Catanzaro, Italy from January 2012 to December 2013 for routine blood tests, were enrolled in the study. Total HDL-, LDL- and non-HDL colesterol, triglycerides, and calcium were determined with standard methods.We observed a significant association between total cholesterol, LDL-cholesterol, HDL-cholesterol, non-HDL cholesterol, triglycerides, and serum calcium in men and postmenopause women. Interestingly, in premenopause women, we only found a direct correlation between serum calcium, total cholesterol, and HDL-cholesterol. Calcium significantly increased while increasing total cholesterol and triglycerides in men and postmenopause women.Our results confirm that progressive increase of serum calcium level correlates with worsening of lipid profile in our study population. Therefore, we suggest that a greater caution should be used in calcium supplement prescription particularly in men and women undergoing menopause, in which an increase of serum lipids is already known to be associated with a higher cardiovascular risk.

  10. Phototropism and geotropism in maize coleoptiles are spatially correlated with increases in cytosolic free calcium.

    Science.gov (United States)

    Gehring, C A; Williams, D A; Cody, S H; Parish, R W

    1990-06-01

    Phototropism and gravitropism in the shoots and roots of higher plants are the result of asymmetric growth. This is explained by the redistribution of growth regulators following exposure to gravity or unilateral light (the Cholodny-Went hypothesis). The positive phototropism and the negative geotropism of grass seedling coleoptiles are believed to result from lateral movement of auxin from the irradiated to the shaded side and from the upper to the lower side, respectively. Many physiological processes in plants, including auxin-induced cell elongation, are reported to be under the control of calcium. Added auxin triggers oscillations in cytosolic free calcium ([Ca2+]cyt) and cytosolic pH (pHcyt) in epidermal cells of maize coleoptiles. Until recently, it has not been possible to visualize these changes spatially with the commonly used fluorescent cation indicators. Using a scanning laser confocal microscope, a new visible wavelength Ca2+ probe fluo-3 and the fluorescent pH indicator BCECF, we have recorded rapid light-induced increases in [Ca2+]cyt and a lowering of pHcyt of cells on the shaded side of maize coleoptiles. In horizontally orientated coleoptiles, [Ca2+]cyt increases and pHcyt decreases in the more rapidly elongating cells on the lower side. For the first time, rapid changes in [Ca2+]cyt and pHcyt are correlated directly with increases in cell elongation stimulated by light and gravity.

  11. Correlation between obstructive coronary artery disease and electron beam tomography coronary artery calcium scan

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Hoon; Hong, Yong Kook; Park, Sung Il; Lee, Hyang Mee; Choe, Kyu Ok [Yonsei Univ. College of Medicine, Seoul (Korea, Republic of)

    1998-08-01

    To determine the correlation between obstructive coronary artery disease and electron beam tomography coronary artery calcium(EBT CAC) scan and to measure the difference in calcium score according to symptoms. Materials and Methods : Fifty-six patients underwent EBT CAC scanning and either coronary angiography or stress thallium 201 scanning or the treadmill test. When the results were positive, coronary artery obstructive disease(CAOD) was assumed to be present. The patients were divided into three groups : symptomatic CAOD,asymptomatic CAOD, and asymptomatic non- CAOD; those with a previous history of myocardial ischemia or who showed positive results in any of the three tests relating to typical symptoms of angina were assigned to the symptomatic group. Results : The number of cases assigned to group to group 1,2 and 3 was 19, 16 and 21, respectively; total CAC scores were 571 {+-} 751, 600 {+-} 726 293{+-} 401, respectively. The difference in CAC score between asymptomatic CAOD and asymptomatic non- CAOD was not statistically significant(p=0.079) but in asymptomatic CAOD, the score tended to be higher. The CAC score was not different between symptomatic and asymptomatic CAOD(p>0.1). When the CAC threshold was 1, sensitivity was 89% and specificity was 14%;when the threshold was 200, sensitivity was 60% and specificity was 67%. Conclusion : When the EBT CAC score is high, further evaluation provides early evidence of coronary artery obstructive disease.

  12. A Novel Synthesis Method of Porous Calcium Silicate Hydrate Based on the Calcium Oxide/Polyethylene Glycol Composites

    OpenAIRE

    Wei Guan; Fangying Ji; Yong Cheng; Zhuoyao Fang; Dexin Fang; Peng Yan; Qingkong Chen

    2013-01-01

    This paper proposed a novel method to prepare porous calcium silicate hydrate (CSH) based on the calcium oxide/polyethylene glycol (CaO/PEG2000) composites as the calcium materials. The porosity formation mechanism was revealed via X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), Brunauer-Emmett-Teller (BET), and Fourier transformed infrared spectroscopy (FT-IR). The reactivity of silica materials (SiO2) enhanced by increasing pH value. Ca2+ could not sustain rele...

  13. Effects of calcium hydroxide addition on the physical and chemical properties of a calcium silicate-based sealer

    OpenAIRE

    KUGA, Milton Carlos; DUARTE Marco Antonio Hungaro; SANT'ANNA-JÚNIOR, Arnaldo; KEINE, Kátia Cristina; FARIA, Gisele; Andrea Abi Rached DANTAS; GUIOTTI, Flávia Angélica

    2014-01-01

    Recently, various calcium silicate-based sealers have been introduced for use in root canal filling. The MTA Fillapex is one of these sealers, but some of its physicochemical properties are not in accordance with the ISO requirements. Objective: The aim of this study was to evaluate the flowability, pH level and calcium release of pure MTA Fillapex (MTAF) or containing 5% (MTAF5) or 10% (MTAF10) calcium hydroxide (CH), in weight, in comparison with AH Plus sealer. Material and Methods: The...

  14. Blended Calcium Aluminate-Calcium Sulfate Cement-Based Grout For P-Reactor Vessel In-Situ Decommissioning

    International Nuclear Information System (INIS)

    The objective of this report is to document laboratory testing of blended calcium aluminate - calcium hemihydrate grouts for P-Reactor vessel in-situ decommissioning. Blended calcium aluminate - calcium hemihydrate cement-based grout was identified as candidate material for filling (physically stabilizing) the 105-P Reactor vessel (RV) because it is less alkaline than portland cement-based grout which has a pH greater than 12.4. In addition, blended calcium aluminate - calcium hemihydrate cement compositions can be formulated such that the primary cementitious phase is a stable crystalline material. A less alkaline material (pH ≤ 10.5) was desired to address a potential materials compatibility issue caused by corrosion of aluminum metal in highly alkaline environments such as that encountered in portland cement grouts (Wiersma, 2009a and b, Wiersma, 2010, and Serrato and Langton, 2010). Information concerning access points into the P-Reactor vessel and amount of aluminum metal in the vessel is provided elsewhere (Griffin, 2010, Stefanko, 2009 and Wiersma, 2009 and 2010, Bobbitt, 2010, respectively). Radiolysis calculations are also provided in a separate document (Reyes-Jimenez, 2010).

  15. BLENDED CALCIUM ALUMINATE-CALCIUM SULFATE CEMENT-BASED GROUT FOR P-REACTOR VESSEL IN-SITU DECOMMISSIONING

    Energy Technology Data Exchange (ETDEWEB)

    Langton, C.; Stefanko, D.

    2011-03-10

    The objective of this report is to document laboratory testing of blended calcium aluminate - calcium hemihydrate grouts for P-Reactor vessel in-situ decommissioning. Blended calcium aluminate - calcium hemihydrate cement-based grout was identified as candidate material for filling (physically stabilizing) the 105-P Reactor vessel (RV) because it is less alkaline than portland cement-based grout which has a pH greater than 12.4. In addition, blended calcium aluminate - calcium hemihydrate cement compositions can be formulated such that the primary cementitious phase is a stable crystalline material. A less alkaline material (pH {<=} 10.5) was desired to address a potential materials compatibility issue caused by corrosion of aluminum metal in highly alkaline environments such as that encountered in portland cement grouts [Wiersma, 2009a and b, Wiersma, 2010, and Serrato and Langton, 2010]. Information concerning access points into the P-Reactor vessel and amount of aluminum metal in the vessel is provided elsewhere [Griffin, 2010, Stefanko, 2009 and Wiersma, 2009 and 2010, Bobbitt, 2010, respectively]. Radiolysis calculations are also provided in a separate document [Reyes-Jimenez, 2010].

  16. The mechanism of hetero-synaptic interaction based on spatiotemporal intracellular calcium dynamics.

    Directory of Open Access Journals (Sweden)

    Daiki Futagi

    2014-03-01

    Full Text Available In recent physiological experiments focusing on synaptic plasticity, it is shown that synaptic modifications induced at one synapse are accompanied by hetero-synaptic changes at neighbor sites (Bi, 2002. These evidences imply that the hetero-synaptic interaction plays an important role in reconfiguration of synaptic connections to form and maintain functional neural circuits (Takahashi et al., 2012. Although the mechanism of the interaction is still unclear, some physiological studies suggest that the hetero-synaptic interaction could be caused by propagation of intracellular calcium signals (Nishiyama et al., 2000. Concretely, a spike-triggered calcium increase initiates calcium ion propagation along a dendrite through activation of molecular processes at neighboring sites. Here we hypothesized that the mechanism of the hetero-synaptic interaction was based on the intracellular calcium signaling, which is regulated by interactions between NMDA receptors (NMDARs, voltage-dependent calcium channels (VDCCs and Ryanodine receptors (RyRs on endoplasmic reticulum (ER. To assess realizability of the hypothesized interaction mechanism, we simulated intracellular calcium dynamics at a cellular level, using the computational model that integrated the model of intracellular calcium dynamics (Keizer and Levine, 1996 and the multi-compartment neuron model (Poirazi et al., 2003. Using the proposed computational model, we induced calcium influxes at a local site in postsynaptic dendrite by controlling the spike timings of pre- and postsynaptic neurons. As a result, synchronized calcium influxes through NMDARs and VDCCs caused calcium release from ER. According to the phase plane analysis, RyR-mediated calcium release occurred when the calcium concentration in cytoplasm sufficiently increased under the condition of a high calcium concentration in ER. An NMDAR-mediated calcium influx was slow and persistent, consequently responsible for maintaining a high

  17. Mortar and concrete based on calcium sulphate binders

    NARCIS (Netherlands)

    Bakker, J.J.F.; Brouwers, H.J.H.

    2006-01-01

    In this study both hemi-hydrate and anhydrite are tested as calcium sulphate binders for structural mortar and concrete. The advantage of using calcium sulphates instead of cement as a binder is the fact that the production of calcium sulphate is more environmental friendly than that of cement. For

  18. Effects of calcium hydroxide addition on the physical and chemical properties of a calcium silicate-based sealer

    Directory of Open Access Journals (Sweden)

    Milton Carlos KUGA

    2014-06-01

    Full Text Available Recently, various calcium silicate-based sealers have been introduced for use in root canal filling. The MTA Fillapex is one of these sealers, but some of its physicochemical properties are not in accordance with the ISO requirements. Objective: The aim of this study was to evaluate the flowability, pH level and calcium release of pure MTA Fillapex (MTAF or containing 5% (MTAF5 or 10% (MTAF10 calcium hydroxide (CH, in weight, in comparison with AH Plus sealer. Material and Methods: The flowability test was performed according to the ISO 6876:2001 requirements. For the pH level and calcium ion release analyses, the sealers were placed individually (n=10 in plastic tubes and immersed in deionized water. After 24 hours, 7 and 14 days, the water in which each specimen had been immersed was evaluated to determine the pH level changes and calcium released. Flowability, pH level and calcium release data were analyzed statistically by the ANOVA test (α=5%. Results: In relation to flowability: MTAF>AH Plus>MTAF5>MTAF10. In relation to the pH level, for 24 h: MTAF5=MTAF10=MTAF>AH Plus; for 7 and 14 days: MTAF5=MTAF10>MTAF>AH Plus. For the calcium release, for all periods: MTAF>MTAF5=MTAF10>AH Plus. Conclusions: The addition of 5% CH to the MTA Fillapex (in weight is an alternative to reduce the high flowability presented by the sealer, without interfering in its alkalization potential.

  19. A Correlation-Based Fingerprint Verification System

    NARCIS (Netherlands)

    Bazen, Asker M.; Verwaaijen, Gerben T.B.; Gerez, Sabih H.; Veelenturf, Leo P.J.; Zwaag, van der Berend Jan

    2000-01-01

    In this paper, a correlation-based fingerprint verification system is presented. Unlike the traditional minutiae-based systems, this system directly uses the richer gray-scale information of the fingerprints. The correlation-based fingerprint verification system first selects appropriate templates i

  20. Modeling Calcium Wave Based on Anomalous Subdiffusion of Calcium Sparks in Cardiac Myocytes

    Science.gov (United States)

    Chen, Xi; Kang, Jianhong; Fu, Ceji; Tan, Wenchang

    2013-01-01

    sparks and waves play important roles in calcium release and calcium propagation during the excitation-contraction (EC) coupling process in cardiac myocytes. Although the classical Fick’s law is widely used to model sparks and waves in cardiac myocytes, it fails to reasonably explain the full-width at half maximum(FWHM) paradox. However, the anomalous subdiffusion model successfully reproduces sparks of experimental results. In this paper, in the light of anomalous subdiffusion of sparks, we develop a mathematical model of calcium wave in cardiac myocytes by using stochastic release of release units (CRUs). Our model successfully reproduces calcium waves with physiological parameters. The results reveal how concentration waves propagate from an initial firing of one CRU at a corner or in the middle of considered region, answer how large in magnitude of an anomalous spark can induce a wave. With physiological currents (2pA) through CRUs, it is shown that an initial firing of four adjacent CRUs can form a wave. Furthermore, the phenomenon of calcium waves collision is also investigated. PMID:23483894

  1. A Novel Synthesis Method of Porous Calcium Silicate Hydrate Based on the Calcium Oxide/Polyethylene Glycol Composites

    Directory of Open Access Journals (Sweden)

    Wei Guan

    2013-01-01

    Full Text Available This paper proposed a novel method to prepare porous calcium silicate hydrate (CSH based on the calcium oxide/polyethylene glycol (CaO/PEG2000 composites as the calcium materials. The porosity formation mechanism was revealed via X-ray diffraction (XRD, field-emission scanning electron microscopy (FESEM, Brunauer-Emmett-Teller (BET, and Fourier transformed infrared spectroscopy (FT-IR. The reactivity of silica materials (SiO2 enhanced by increasing pH value. Ca2+ could not sustain release from CaO/PEG2000 and reacted with caused by silica to form CSH until the hydrothermal temperature reached to 170°C, avoiding the hardly dissolved intermediates formation efficiently. The as-prepared CSH, due to the large specific surface areas, exhibited excellent release capability of Ca2+ and OH−. This porous CSH has potential application in reducing the negative environmental effects of continual natural phosphate resource depletion.

  2. COMPUTER AIDED DESIGN OF SELECTIVE CALCIUM CHANNEL BLOCKERS: USING PHARMACOPHORE - BASED AND DOCKING SIMULATIONS

    Directory of Open Access Journals (Sweden)

    Reetu

    2012-03-01

    Full Text Available In the present study, 3-D QSAR analysis was performed on the previously synthesized and evaluated derivatives of novel 2-arylthiazolidinones as selective analgesic N-type calcium channel blockers. Calcium Channel blockers is the molecular target responsible for the treatment of neuropathic and inflammatory pain. The 3D-QSAR study based on the principle of the alignment of pharmacophoric features by PHASE module of Schrodinger suite has been carried out on the same set of calcium channel blockers. Statistically significant 3-D QSAR model (R2=0.9288 were generated using 21 molecules in the training set. The predictive ability of model was determined using a randomly chosen test set of 6 molecules which gave predictive correlation coefficients (R2pred of 0.946 for 3-D models, indicating good predictive power. PHASE pharmacophore hypothesis AAHR.13 may correspond very closely to the interactions recorded in the active site of the ligand bound complex. These studies produced models with high correlation coefficient and good predictive abilities. Docking studies were also carried out wherein these analogues were docked into the active sites of COX-2 to analyze the receptor-ligand interactions that confer selectivity for COX-2. Compound 2 have the highest dock score (-7.28. In the active site, there are some strong hydrogen-bonding interactions observed between residues GLU67, ALA103, ASP96, SER184 and ASP22. Additionally a correlation of the quantitative structure –activity relationship data and the docking results is found to validate each other and suggest the importance of the binding step in overall drug action.

  3. Mortar and concrete based on calcium sulphate binders

    OpenAIRE

    Bakker, J.J.F.; Brouwers, H. J. H.

    2006-01-01

    In this study both hemi-hydrate and anhydrite are tested as calcium sulphate binders for structural mortar and concrete. The advantage of using calcium sulphates instead of cement as a binder is the fact that the production of calcium sulphate is more environmental friendly than that of cement. For the calcinations of Portland cement, temperatures up to 1480 oC are needed, while the calcination of for instance hemihydrate requires a temperature of 170 oC

  4. Protein-specific localization of a rhodamine-based calcium-sensor in living cells.

    Science.gov (United States)

    Best, Marcel; Porth, Isabel; Hauke, Sebastian; Braun, Felix; Herten, Dirk-Peter; Wombacher, Richard

    2016-06-28

    A small synthetic calcium sensor that can be site-specifically coupled to proteins in living cells by utilizing the bio-orthogonal HaloTag labeling strategy is presented. We synthesized an iodo-derivatized BAPTA chelator with a tetramethyl rhodamine fluorophore that allows further modification by Sonogashira cross-coupling. The presented calcium sensitive dye shows a 200-fold increase in fluorescence upon calcium binding. The derivatization with an aliphatic linker bearing a terminal haloalkane-function by Sonogashira cross-coupling allows the localization of the calcium sensor to Halo fusion proteins which we successfully demonstrate in in vitro and in vivo experiments. The herein reported highly sensitive tetramethyl rhodamine based calcium indicator, which can be selectively localized to proteins, is a powerful tool to determine changes in calcium levels inside living cells with spatiotemporal resolution. PMID:27072883

  5. A CALCIUM-BASED INVASION RISK ASSESSMENT FOR ZEBRA AND QUAGGA MUSSELS (DREISSENA SPP.)

    Science.gov (United States)

    We used calcium concentration data from over 3000 stream and river sites across the contiguous United States to classify ecoregions relative to their risk for Dreissena species invasion. We defined risk based on calcium concentrations as: very low (< 12 mg L−1), low (12–20 mg L−1...

  6. Effect of acute acid loading on acid-base and calcium metabolism

    DEFF Research Database (Denmark)

    Osther, Palle J

    2006-01-01

    OBJECTIVE: To investigate the acid-base and calcium metabolic responses to acute non-carbonic acid loading in idiopathic calcium stone-formers and healthy males using a quantitative organ physiological approach. MATERIAL AND METHODS: Five-h ammonium chloride loading studies were performed in 12 m...

  7. EXPERIMENTAL EVALUATION OF LOW CALCIUM FLY ASH BASED GEOPOLYMER CONCRETE

    Directory of Open Access Journals (Sweden)

    NIRAGI DAVE

    2012-12-01

    Full Text Available There are many ways to reduce environmental pollution that causes by production of Portland cement and cause by the increasing of waste material. Geopolymer concrete results from the reaction of a source material that is rich in silica and alumina with alkaline liquid. In this experiment low calcium (ASTM Class F fly ash based Geopolymer is used as the binder, in the replacement of portland cement to produce Geopolymer concrete. The alkaline liquid that been used in geopolymerisation is the combination of sodium hydroxide (NaOH and sodium metasilicate (Na2Sio2. Fly ash has been collected from Badarpur NTPC plant, New Delhi. In the present study, three (3 series of geopolymer concrete specimens composing molar of sodium hydroxide (NaOH which is 8M was adopted. There are 9 cube specimens at size 150mm x 150mm x 150mm were prepared. The test specimenswere cured at 60 degree in an oven and at ambient condition. The curing time varied from 24 hour to 168 hours (7 days. The result shows that the strength of geopolymer concrete after 24 hour is not superior and after 7 day the compressive strength of Geopolymer concrete is moderate. Therefore further curing period and temperatureshould be improved.

  8. MERCURY CONTROL WITH CALCIUM-BASED SORBENTS AND OXIDIZING AGENTS

    Energy Technology Data Exchange (ETDEWEB)

    Thomas K. Gale

    2002-06-01

    The initial tasks of this DOE funded project to investigate mercury removal by calcium-based sorbents have been completed, and initial testing results have been obtained. Mercury monitoring capabilities have been obtained and validated. An approximately 1MW (3.4 Mbtu/hr) Combustion Research Facility at Southern Research Institute was used to perform pilot-scale investigations of mercury sorbents, under conditions representative of full-scale boilers. The initial results of ARCADIS G&M proprietary sorbents, showed ineffective removal of either elemental or oxidized mercury. Benchscale tests are currently underway to ascertain the importance of differences between benchscale and pilot-scale experiments. An investigation of mercury-capture temperature dependence using common sorbents has also begun. Ordinary hydrated lime removed 80 to 90% of the mercury from the flue gas, regardless of the temperature of injection. High temperature injection of hydrated lime simultaneously captured SO{sub 2} at high temperatures and Hg at low temperatures, without any deleterious effects on mercury speciation. Future work will explore alternative methods of oxidizing elemental mercury.

  9. Modeling of calcium-based sorbent reactions with sulfur dioxide

    Directory of Open Access Journals (Sweden)

    Tomanović Ivan

    2015-01-01

    Full Text Available A mathematical model of calcium sorbent reactions for simulation of sulfur dioxide reduction from pulverized coal combustion fl e gasses is developed, implemented within numerical code and validated against available measurements under controlled conditions. The model attempts to closely resemble reactions of calcination, sintering and sulfation, occurring during the sorbent particles motion in the furnace. The sulfation is based on PSSM (Partially Sintered Spheres Model, coupled with simulated particle calcination and sintering. Complex geometry of the particle is taken into account, with the assumption that it consists of spherical grains in contact with each other. Numerical simulations of drop down tube reactors were performed for both CaCO3 and Ca(OH2 sorbent particles and results were compared with available experimental data from literature. The sorbent reactions model will be further used for simulations of desulfurization reactions in turbulent gas-particle flow under coalcombustion conditions. [Projekat Ministarstva nauke Republike Srbije, br. TR-33018: Increase in energy and ecology efficiency of processes in pulverized coal-fired furnace and optimization of utility steam boiler air preheater by using in-house developed software tools

  10. Correlation of Cell Strain in Single Osteocytes with Intracellular Calcium, but not Intracellular Nitric Oxide, in Response to Fluid Flow

    OpenAIRE

    Rath, Amber L.; Bonewald, Lynda F.; Ling, Jian; Jiang, Jean X.; VAN DYKE, MARK E.; Nicolella, Daniel P

    2010-01-01

    Osteocytes compose 90–95% of all bone cells and are the mechanosensors of bone. In this study, the strain experienced by individual osteocytes resulting from an applied fluid flow shear stress was quantified and correlated to two biological responses measured in real-time within the same individual osteocytes: 1) the upregulation of intracellular calcium and 2) changes in intracellular nitric oxide. Osteocyte-like MLO-Y4 cells were loaded with Fluo-4 AM and DAR-4M and exposed to uniform lamin...

  11. Calcium-based multi-element chemistry for grid-scale electrochemical energy storage

    Science.gov (United States)

    Ouchi, Takanari; Kim, Hojong; Spatocco, Brian L.; Sadoway, Donald R.

    2016-01-01

    Calcium is an attractive material for the negative electrode in a rechargeable battery due to its low electronegativity (high cell voltage), double valence, earth abundance and low cost; however, the use of calcium has historically eluded researchers due to its high melting temperature, high reactivity and unfavorably high solubility in molten salts. Here we demonstrate a long-cycle-life calcium-metal-based rechargeable battery for grid-scale energy storage. By deploying a multi-cation binary electrolyte in concert with an alloyed negative electrode, calcium solubility in the electrolyte is suppressed and operating temperature is reduced. These chemical mitigation strategies also engage another element in energy storage reactions resulting in a multi-element battery. These initial results demonstrate how the synergistic effects of deploying multiple chemical mitigation strategies coupled with the relaxation of the requirement of a single itinerant ion can unlock calcium-based chemistries and produce a battery with enhanced performance. PMID:27001915

  12. Calcium-based multi-element chemistry for grid-scale electrochemical energy storage

    Science.gov (United States)

    Ouchi, Takanari; Kim, Hojong; Spatocco, Brian L.; Sadoway, Donald R.

    2016-03-01

    Calcium is an attractive material for the negative electrode in a rechargeable battery due to its low electronegativity (high cell voltage), double valence, earth abundance and low cost; however, the use of calcium has historically eluded researchers due to its high melting temperature, high reactivity and unfavorably high solubility in molten salts. Here we demonstrate a long-cycle-life calcium-metal-based rechargeable battery for grid-scale energy storage. By deploying a multi-cation binary electrolyte in concert with an alloyed negative electrode, calcium solubility in the electrolyte is suppressed and operating temperature is reduced. These chemical mitigation strategies also engage another element in energy storage reactions resulting in a multi-element battery. These initial results demonstrate how the synergistic effects of deploying multiple chemical mitigation strategies coupled with the relaxation of the requirement of a single itinerant ion can unlock calcium-based chemistries and produce a battery with enhanced performance.

  13. Biocompatibility and bioactivity of calcium silicate-based endodontic sealers in human dental pulp cells

    OpenAIRE

    Leticia Boldrin MESTIERI; GOMES-CORNÉLIO, Ana Lívia; RODRIGUES, Elisandra Márcia; SALLES, Loise Pedrosa; BOSSO-MARTELO, Roberta; Juliane Maria GUERREIRO-TANOMARU; TANOMARU-FILHO, Mário

    2015-01-01

    Mineral Trioxide Aggregate (MTA) is a calcium silicate-based material. New sealers have been developed based on calcium silicate as MTA Fillapex and MTA Plus. Objective The aim of this study was to evaluate biocompatibility and bioactivity of these two calcium silicate-based sealers in culture of human dental pulp cells (hDPCs). Material and Methods The cells were isolated from third molars extracted from a 16-year-old patient. Pulp tissue was sectioned into fragments with approximately 1 mm3...

  14. Optical correlation recognition based on LCOS

    Science.gov (United States)

    Tang, Mingchuan; Wu, Jianhong

    2013-08-01

    Vander-Lugt correlator[1] plays an important role in optical pattern recognition due to the characteristics of accurate positioning and high signal-to-noise ratio. The ideal Vander-Lugt correlator should have the ability of outputting strong and sharp correlation peak in allusion to the true target, in the existing Spatial Light Modulators[2], Liquid Crystal On Silicon(LCOS) has been the most competitive candidate for the matched filter owing to the continuous phase modulation peculiarity. Allowing for the distortions of the target to be identified including rotations, scaling changes, perspective changes, which can severely impact the correlation recognition results, herein, we present a modified Vander-Lugt correlator based on the LCOS by means of applying an iterative algorithm to the design of the filter so that the correlator can invariant to the distortions while maintaining good performance. The results of numerical simulation demonstrate that the filter could get the similar recognition results for all the training images. And the experiment shows that the modified correlator achieves the 180° rotating tolerance significantly improving the recognition efficiency of the correlator.

  15. Modulation of cytosolic-free calcium transients by changes in intracellular calcium-buffering capacity: correlation with exocytosis and O2-production in human neutrophils

    OpenAIRE

    1984-01-01

    The intracellularly trapped fluorescent calcium indicator, quin 2, was used not only to monitor changes in cytosolic-free calcium, [Ca2+]i, but also to assess the role of [Ca2+]i in neutrophil function. To increase cytosolic calcium buffering, human neutrophils were loaded with various quin 2 concentrations, and [Ca2+]i transients, granule content release as well as superoxide [O2-] production were measured in response to the chemotactic peptide formyl-methionyl-leucyl- phenylalanine (fMLP) a...

  16. Experimental research on combustion fluorine retention using calcium-based sorbets during coal combustion (Ⅰ)

    Institute of Scientific and Technical Information of China (English)

    QI Qing-jie; LIN Zhi-yan; LIU Jian-zhong; WU Xian; ZHOU Jun-hu; CEN Ke-fa

    2008-01-01

    In order to provide experimental guide to commercial use of fluorine pollution control during coal combustion, with fluorine pollution control during coal combustion in mind, this paper proposed the theory of combustion fluorine retention technology. Feasibility of fluorine retention reaction with calcium-based fluorine retention agent was analyzed through thermo-dynamic calculation during coal combustion. By simulating the restraining and retention effects and influential factors of calcium-based sorbets on vaporized fluoride during experimental combustion using fixed bed tube furnace, the paper systematically explored the influential law of such factors as combustion temperature, retention time, and added quantities of calcium-based sorbets on effects of fluorine retention. The research result shows that adding calcium-based fluorine retention agent in coal combustion has double effects of fluorine retention and sulfur retention, it lays an experimental foundation for commercial test of combustion fluorine retention.

  17. Quotient correlation: A sample based alternative to Pearson's correlation

    OpenAIRE

    Zhang, Zhengjun

    2008-01-01

    The quotient correlation is defined here as an alternative to Pearson’s correlation that is more intuitive and flexible in cases where the tail behavior of data is important. It measures nonlinear dependence where the regular correlation coefficient is generally not applicable. One of its most useful features is a test statistic that has high power when testing nonlinear dependence in cases where the Fisher’s Z-transformation test may fail to reach a right conclusion. Unlike most asymptotic t...

  18. Durability Study on High Calcium Fly Ash Based Geopolymer Concrete

    OpenAIRE

    Ganesan Lavanya; Josephraj Jegan

    2015-01-01

    This study presents an investigation into the durability of geopolymer concrete prepared using high calcium fly ash along with alkaline activators when exposed to 2% solution of sulfuric acid and 5% magnesium sulphate for up to 45 days. The durability was also assessed by measuring water absorption and sorptivity. Ordinary Portland cement concrete was also prepared as control concrete. The grades chosen for the investigation were M20, M40, and M60. The alkaline solution used for present study...

  19. Upper Subcritical Calculations Based on Correlated Data

    Energy Technology Data Exchange (ETDEWEB)

    Sobes, Vladimir [ORNL; Rearden, Bradley T [ORNL; Mueller, Don [ORNL; Marshall, William BJ J [ORNL; Scaglione, John M [ORNL; Dunn, Michael E [ORNL

    2015-01-01

    The American National Standards Institute and American Nuclear Society standard for Validation of Neutron Transport Methods for Nuclear Criticality Safety Calculations defines the upper subcritical limit (USL) as “a limit on the calculated k-effective value established to ensure that conditions calculated to be subcritical will actually be subcritical.” Often, USL calculations are based on statistical techniques that infer information about a nuclear system of interest from a set of known/well-characterized similar systems. The work in this paper is part of an active area of research to investigate the way traditional trending analysis is used in the nuclear industry, and in particular, the research is assessing the impact of the underlying assumption that the experimental data being analyzed for USL calculations are statistically independent. In contrast, the multiple experiments typically used for USL calculations can be correlated because they are often performed at the same facilities using the same materials and measurement techniques. This paper addresses this issue by providing a set of statistical inference methods to calculate the bias and bias uncertainty based on the underlying assumption that the experimental data are correlated. Methods to quantify these correlations are the subject of a companion paper and will not be discussed here. The newly proposed USL methodology is based on the assumption that the integral experiments selected for use in the establishment of the USL are sufficiently applicable and that experimental correlations are known. Under the assumption of uncorrelated data, the new methods collapse directly to familiar USL equations currently used. We will demonstrate our proposed methods on real data and compare them to calculations of currently used methods such as USLSTATS and NUREG/CR-6698. Lastly, we will also demonstrate the effect experiment correlations can have on USL calculations.

  20. In Vitro Cytotoxicity of Calcium Silicate-Based Endodontic Cement as Root-End Filling Materials

    OpenAIRE

    Selen Küçükkaya; Mehmet Ömer Görduysus; Naciye Dilara Zeybek; Sevda Fatma Müftüoğlu

    2016-01-01

    The aim of this study was to evaluate the cytotoxicity of three types of calcium silicate-based endodontic cement after different incubation periods with human periodontal ligament fibroblasts. Human periodontal ligament fibroblasts were cultured from extracted third molars and seeded in 96-well plates. MTA, calcium enriched mixture (CEM) cement, and Biodentine were prepared and added to culture insert plates which were immediately placed into 96-well plates containing cultured cells. After i...

  1. Calcium Silicate-Based Cements Associated with Micro- and Nanoparticle Radiopacifiers: Physicochemical Properties and Bioactivity

    OpenAIRE

    BOSSO-MARTELO, Roberta; Juliane Maria GUERREIRO-TANOMARU; Viapiana, Raqueli; Berbert, Fábio Luis Camargo Vilella; Basso Bernardi, Maria Inês; Tanomaru-Filho, Mario

    2015-01-01

    Objective. The aim of this study was to evaluate the physicochemical properties and bioactivity of two formulations of calcium silicate-based cements containing additives (CSCM) or resin (CSCR), associated with radiopacifying agents zirconium oxide (ZrO2) and niobium oxide (Nb2O5) as micro- and nanoparticles; calcium tungstate (CaWO4); and bismuth oxide (Bi2O3). MTA Angelus was used as control. Methods. Surface features and bioactivity were evaluated by scanning electron microscopy and the ch...

  2. Gait correlation analysis based human identification.

    Science.gov (United States)

    Chen, Jinyan

    2014-01-01

    Human gait identification aims to identify people by a sequence of walking images. Comparing with fingerprint or iris based identification, the most important advantage of gait identification is that it can be done at a distance. In this paper, silhouette correlation analysis based human identification approach is proposed. By background subtracting algorithm, the moving silhouette figure can be extracted from the walking images sequence. Every pixel in the silhouette has three dimensions: horizontal axis (x), vertical axis (y), and temporal axis (t). By moving every pixel in the silhouette image along these three dimensions, we can get a new silhouette. The correlation result between the original silhouette and the new one can be used as the raw feature of human gait. Discrete Fourier transform is used to extract features from this correlation result. Then, these features are normalized to minimize the affection of noise. Primary component analysis method is used to reduce the features' dimensions. Experiment based on CASIA database shows that this method has an encouraging recognition performance. PMID:24592144

  3. Gait Correlation Analysis Based Human Identification

    Directory of Open Access Journals (Sweden)

    Jinyan Chen

    2014-01-01

    Full Text Available Human gait identification aims to identify people by a sequence of walking images. Comparing with fingerprint or iris based identification, the most important advantage of gait identification is that it can be done at a distance. In this paper, silhouette correlation analysis based human identification approach is proposed. By background subtracting algorithm, the moving silhouette figure can be extracted from the walking images sequence. Every pixel in the silhouette has three dimensions: horizontal axis (x, vertical axis (y, and temporal axis (t. By moving every pixel in the silhouette image along these three dimensions, we can get a new silhouette. The correlation result between the original silhouette and the new one can be used as the raw feature of human gait. Discrete Fourier transform is used to extract features from this correlation result. Then, these features are normalized to minimize the affection of noise. Primary component analysis method is used to reduce the features’ dimensions. Experiment based on CASIA database shows that this method has an encouraging recognition performance.

  4. Do Ca2+-adsorbing ceramics reduce the release of calcium ions from gypsum-based biomaterials?

    Science.gov (United States)

    Belcarz, Anna; Zalewska, Justyna; Pałka, Krzysztof; Hajnos, Mieczysław; Ginalska, Grazyna

    2015-02-01

    Bone implantable materials based on calcium sulfate dihydrate dissolve quickly in tissue liquids and release calcium ions at very high levels. This phenomenon induces temporary toxicity for osteoblasts, may cause local inflammation and delay the healing process. Reduction in the calcium ion release rate by gypsum could be therefore beneficial for the healing of gypsum-filled bone defects. The aim of this study concerned the potential use of calcium phosphate ceramics of various porosities for the reduction of high Ca(2+) ion release from gypsum-based materials. Highly porous ceramics failed to reduce the level of Ca(2+) ions released to the medium in a continuous flow system. However, it succeeded to shorten the period of high calcium level. It was not the phase composition but the high porosity of ceramics that was found crucial for both the shortening of the Ca(2+) release-related toxicity period and intensification of apatite deposition on the composite. Nonporous ceramics was completely ineffective for this purpose and did not show any ability to absorb calcium ions at a significant level. Moreover, according to our observations, complex studies imitating in vivo systems, rather than standard tests, are essential for the proper evaluation of implantable biomaterials. PMID:25492196

  5. Leaching characteristics of calcium-based compounds in MSWI Residues: From the viewpoint of clogging risk

    International Nuclear Information System (INIS)

    Highlights: • The leaching behavior of Ca-based compounds commonly in MSWI residues was studied. • pH is the crucial factor for calcium leaching process. • CaCO3 was the most sensitive to leaching temperature and Ca3(PO4)2 was the least. • Ca leaching of MSWIBA and SAPCR attributed to CaCO3 and Ca3(PO4)2 respectively. • Potential clogging ability of MSWI residues leachate in open air was calculated. - Abstract: Leachate collection system (LCS) clogging caused by calcium precipitation would be disadvantageous to landfill stability and operation. Meanwhile, calcium-based compounds are the main constituents in both municipal solid waste incineration bottom ash (MSWIBA) and stabilized air pollution control residues (SAPCR), which would increase the risk of LCS clogging once these calcium-rich residues were disposed in landfills. The leaching behaviors of calcium from the four compounds and municipal solid waste incineration (MSWI) residues were studied, and the influencing factors on leaching were discussed. The results showed that pH was the crucial factor in the calcium leaching process. CaCO3 and CaSiO3 began leaching when the leachate pH decreased to less than 7 and 10, respectively, while Ca3(PO4)2 leached at pH < 12. CaSO4 could hardly dissolve in the experimental conditions. Moreover, the sequence of the leaching rate for the different calcium-based compounds is as follows: CaSiO3 > Ca3(PO4)2 > CaCO3. The calcium leaching from the MSWIBA and SAPCR separately started from pH < 7 and pH < 12, resulting from CaCO3 and Ca3(PO4)2 leaching respectively, which was proven by the X-ray diffraction results. Based on the leaching characteristics of the different calcium compounds and the mineral phase of calcium in the incineration residues, simulated computation of their clogging potential was conducted, providing the theoretical basis for the risk assessment pertaining to LCS clogging in landfills

  6. Leaching characteristics of calcium-based compounds in MSWI Residues: From the viewpoint of clogging risk

    Energy Technology Data Exchange (ETDEWEB)

    Xia, Yi [State Key Laboratory of Pollution Control & Resource Reuse, Tongji University, Shanghai 200092 (China); Institute of Waste Treatment and Reclamation, Tongji University, Shanghai 200092 (China); Zhang, Hua, E-mail: zhanghua_tj@tongji.edu.cn [State Key Laboratory of Pollution Control & Resource Reuse, Tongji University, Shanghai 200092 (China); Phoungthong, Khamphe [State Key Laboratory of Pollution Control & Resource Reuse, Tongji University, Shanghai 200092 (China); Institute of Waste Treatment and Reclamation, Tongji University, Shanghai 200092 (China); Shi, Dong-Xiao; Shen, Wen-Hui [Changzhou Domestic Waste Treatment Center, Changzhou 213000 (China); Shao, Li-Ming [Institute of Waste Treatment and Reclamation, Tongji University, Shanghai 200092 (China); Center for the Technology Research and Training on Household Waste in Small Towns & Rural Area, Ministry of Housing and Urban–Rural Development of PR China (MOHURD), Shanghai 200092 (China); He, Pin-Jing, E-mail: solidwaste@tongji.edu.cn [Institute of Waste Treatment and Reclamation, Tongji University, Shanghai 200092 (China); Center for the Technology Research and Training on Household Waste in Small Towns & Rural Area, Ministry of Housing and Urban–Rural Development of PR China (MOHURD), Shanghai 200092 (China)

    2015-08-15

    Highlights: • The leaching behavior of Ca-based compounds commonly in MSWI residues was studied. • pH is the crucial factor for calcium leaching process. • CaCO{sub 3} was the most sensitive to leaching temperature and Ca{sub 3}(PO{sub 4}){sub 2} was the least. • Ca leaching of MSWIBA and SAPCR attributed to CaCO{sub 3} and Ca{sub 3}(PO{sub 4}){sub 2} respectively. • Potential clogging ability of MSWI residues leachate in open air was calculated. - Abstract: Leachate collection system (LCS) clogging caused by calcium precipitation would be disadvantageous to landfill stability and operation. Meanwhile, calcium-based compounds are the main constituents in both municipal solid waste incineration bottom ash (MSWIBA) and stabilized air pollution control residues (SAPCR), which would increase the risk of LCS clogging once these calcium-rich residues were disposed in landfills. The leaching behaviors of calcium from the four compounds and municipal solid waste incineration (MSWI) residues were studied, and the influencing factors on leaching were discussed. The results showed that pH was the crucial factor in the calcium leaching process. CaCO{sub 3} and CaSiO{sub 3} began leaching when the leachate pH decreased to less than 7 and 10, respectively, while Ca{sub 3}(PO{sub 4}){sub 2} leached at pH < 12. CaSO{sub 4} could hardly dissolve in the experimental conditions. Moreover, the sequence of the leaching rate for the different calcium-based compounds is as follows: CaSiO{sub 3} > Ca{sub 3}(PO{sub 4}){sub 2} > CaCO{sub 3}. The calcium leaching from the MSWIBA and SAPCR separately started from pH < 7 and pH < 12, resulting from CaCO{sub 3} and Ca{sub 3}(PO{sub 4}){sub 2} leaching respectively, which was proven by the X-ray diffraction results. Based on the leaching characteristics of the different calcium compounds and the mineral phase of calcium in the incineration residues, simulated computation of their clogging potential was conducted, providing the

  7. Phase Correlation Based Iris Image Registration Model

    Institute of Scientific and Technical Information of China (English)

    Jun-Zhou Huang; Tie-Niu Tan; Li Ma; Yun-Hong Wang

    2005-01-01

    Iris recognition is one of the most reliable personal identification methods. In iris recognition systems, image registration is an important component. Accurately registering iris images leads to higher recognition rate for an iris recognition system. This paper proposes a phase correlation based method for iris image registration with sub-pixel accuracy.Compared with existing methods, it is insensitive to image intensity and can compensate to a certain extent the non-linear iris deformation caused by pupil movement. Experimental results show that the proposed algorithm has an encouraging performance.

  8. Adhesion property of epoxidized natural rubber (ENR-based adhesives containing calcium carbonate

    Directory of Open Access Journals (Sweden)

    2008-06-01

    Full Text Available The adhesion property (i.e. viscosity, loop tack and peel strength of epoxidized natural rubber (ENR 25 and ENR 50 grade-based pressure-sensitive adhesive was studied in the presence of calcium carbonate. The range of calcium carbonate loaded was from 10 to 50 parts per hundred parts of rubber (phr. Coumarone-indene resin was used as the tackifier and its concentration was fixed at 80 phr. Toluene was chosen as the solvent throughout the investigation. The substrates (PET film/paper were coated with the adhesive using a SHEEN hand coater at a coating thickness of 60 µm. Viscosity of the adhesive was measured by a HAAKE Rotary Viscometer whereas loop tack and peel strength were determined by a Llyod Adhesion Tester operating at 30 cm/min. Results show that viscosity of ENR-based adhesives increases gradually with increase in calcium carbonate loading due to the concentration effect of the filler. However, for loop tack and peel strength, it passes through a maximum at 30 phr calcium carbonate, an observation which is attributed to the optimum wettability of adhesive on the substrate at this adhesive composition. ENR 25-based adhesive consistently exhibits higher adhesion property than ENR 50 for all calcium carbonate loadings studied.

  9. SIMULTANEOUS CONTROL OF HGO, SO2, AND NOX BY NOVEL OXIDIZED CALCIUM-BASED SORBENTS

    Science.gov (United States)

    The paper gives results of an investigation of two classes of calcium (Ca)-based sorbents (hydrated limes and silicate compounds). (NOTE: Efforts to develop multipollutant control strategies have demonstrated that adding certain oxidants to different classes of Ca-based sorbents...

  10. SIMULTANEOUS CONTROL OF HG(0), SO2, AND NOX BY NOVEL OXIDIZED CALCIUM-BASED SORBENTS

    Science.gov (United States)

    The paper gives results of an investigation of two classes of calcium (Ca)-based sorbents (hydrated limes and silicate compounds). {NOTE: Efforts to develop multipollutant control strategies have demonstrated that adding certain oxidants to different classes of Ca-based sorbents ...

  11. Durability Study on High Calcium Fly Ash Based Geopolymer Concrete

    Directory of Open Access Journals (Sweden)

    Ganesan Lavanya

    2015-01-01

    Full Text Available This study presents an investigation into the durability of geopolymer concrete prepared using high calcium fly ash along with alkaline activators when exposed to 2% solution of sulfuric acid and 5% magnesium sulphate for up to 45 days. The durability was also assessed by measuring water absorption and sorptivity. Ordinary Portland cement concrete was also prepared as control concrete. The grades chosen for the investigation were M20, M40, and M60. The alkaline solution used for present study is the combination of sodium silicate and sodium hydroxide solution with the ratio of 2.50. The molarity of sodium hydroxide was fixed as 12. The test specimens were 150×150×150 mm cubes, 100×200 mm cylinders, and 100×50 mm discs cured at ambient temperature. Surface deterioration, density, and strength over a period of 14, 28, and 45 days were observed. The results of geopolymer and ordinary Portland cement concrete were compared and discussed. After 45 days of exposure to the magnesium sulfate solution, the reduction in strength was up to 12% for geopolymer concrete and up to 25% for ordinary Portland cement concrete. After the same period of exposure to the sulphuric acid solution, the compressive strength decrease was up to 20% for geopolymer concrete and up to 28% for ordinary Portland cement concrete.

  12. Consistency based correlations for tailings consolidation

    Energy Technology Data Exchange (ETDEWEB)

    Azam, S.; Paul, A.C. [Regina Univ., Regina, SK (Canada). Environmental Systems Engineering

    2010-07-01

    The extraction of oil, uranium, metals and mineral resources from the earth generates significant amounts of tailings slurry. The tailings are contained in a disposal area with perimeter dykes constructed from the coarser fraction of the slurry. There are many unique challenges pertaining to the management of the containment facilities for several decades beyond mine closure that are a result of the slow settling rates of the fines and the high standing toxic waters. Many tailings dam failures in different parts of the world have been reported to result in significant contaminant releases causing public concern over the conventional practice of tailings disposal. Therefore, in order to reduce and minimize the environmental footprint, the fluid tailings need to undergo efficient consolidation. This paper presented an investigation into the consolidation behaviour of tailings in conjunction with soil consistency that captured physicochemical interactions. The paper discussed the large strain consolidation behaviour (volume compressibility and hydraulic conductivity) of six fine-grained soil slurries based on published data. The paper provided background information on the study and presented the research methodology. The geotechnical index properties of the selected materials were also presented. The large strain consolidation, volume compressibility correlations, and hydraulic conductivity correlations were provided. It was concluded that the normalized void ratio best described volume compressibility whereas liquidity index best explained the hydraulic conductivity. 17 refs., 3 tabs., 4 figs.

  13. Changes of intracellular calcium and the correlation with functional damage of the spinal cord after spinal cord injury

    Institute of Scientific and Technical Information of China (English)

    章亚东; 侯树勋; 吴叶

    2002-01-01

    Objective: To observe dynamic changes of intracellular calcium ([Ca2+]i) after spinal cord injury, and to study the relationship between the changes of [Ca2+]i and the functional damage of the spinal cord.   Methods: The rats were subjected to a spinal cord contusion by using a modified Allens method. The [Ca2+]i in the injured segment of the spinal cord was measured by the technique of La3+ blockage and atomic absorption spectroscopy at 1, 4, 8, 24, 72, and 168 hours after injury. The motor function on the inclined plane was measured at the same time.   Results: The spinal cord [Ca2+]i increased significantly (P<0.05 or P<0.01) after spinal cord injury. There was a significant correlation (P<0.05) between the changes of [Ca2+]i and the motor function.   Conclusions: [Ca2+]i overload may play an important role in the pathogenesis of spinal cord injury.

  14. Fluorine-fixing efficiency on calcium-based briquette: pilot experiment, demonstration and promotion

    Institute of Scientific and Technical Information of China (English)

    YANG Jiao-lan; CHEN Dong-qing; LI Shu-min; YUE Yin-ling; JIN Xin; ZHAO Bing-cheng; YING Bo

    2010-01-01

    Background The fluorosis derived from coal burning is a very serious problem in China. By using fluorine-fixing technology during coal burning we are able to reduce the release of fluorides in coal at the source in order to reduce pollution to the surrounding environment by coal burning pollutants as well as decrease the intake and accumulating amounts of fluorine in the human body. The aim of this study was to conduct a pilot experiment on calcium-based fluorine-fixing material efficiency during coal burning to demonstrate and promote the technology based on laboratory research.Methods A proper amount of calcium-based fluorine sorbent was added into high-fluorine coal to form briquettes so that the fluorine in high-fluorine coal can be fixed in coal slag and its release into atmosphere reduced. We determined figures on various components in briquettes and fluorine in coal slag as well as the concentrations of indoor air pollutants, including fluoride, sulfur dioxide and respirable particulate matter (RPM), and evaluated the fluorine-fixing efficiency of calcium-based fluorine sorbents and the levels of indoor air pollutants.Results Pilot experiments on fluorine-fixing efficiency during coal burning as well as its demonstration and promotion were carried out separately in Guiding and Longli Counties of Guizhou Province, two areas with coal burning fluorosis problems. If the calcium-based fluorine sorbent mixed coal was made into honeycomb briquettes the average fluorine-fixing ratio in the pilot experiment was 71.8%. If the burning calcium-based fluorine-fixing bitumite was made into a coalball, the average of fluorine-fixing ratio was 77.3%. The concentration of fluoride, sulfur dioxide and PM10 of indoor air were decreased significantly. There was a 10% increase in the cost of briquettes due to the addition of calcium-based fluorine sorbent.Conclusions The preparation process of calcium-based fluorine-fixing briquette is simple yet highly flammable and it is

  15. A Reusable Calcium-Based Sorbent for Desulfurizing Hot Coal Gas

    Energy Technology Data Exchange (ETDEWEB)

    Wheelock, T.D.; Hasler, D.J.L.

    2002-09-19

    The overall objective of this project has been to develop a superior, regenerable, calcium-based sorbent for desulfurizing hot coal gas. The sorbent should be strong, durable, inexpensive to manufacture, and capable of being reused many times. To achieve these objectives the project has focused on the development of the very promising core-in-shell sorbent.

  16. Calcium Oxide Supported on Monoclinic Zirconia as a Highly Active Solid Base Catalyst

    NARCIS (Netherlands)

    Frey, A.M.; van Haasterecht, T.; de Jong, K.P.; Bitter, J.H.

    2013-01-01

    Calcium oxide supported on ZrO2 is a highly active catalyst for base-catalyzed reactions such as aldol-type reactions and transesterification reactions. The role of key parameters during preparation, that is, impregnation versus precipitation, heat treatment, and metal oxide loading on the basicity

  17. Effect of the presence of HCl on cyclic CO2 capture of calcium-based sorbent in calcium looping process

    International Nuclear Information System (INIS)

    Highlights: • HCl improves CO2 capture capacity of limestone in the previous a dozen cycles. • HCl sharply decreases limestone reactivity after a dozen cycles. • HCl intensifies effects of carbonation and calcination temperature on CO2 capture. • HCl enlarges effects of particle size on CO2 capture. • HCl severely aggravates the sintering of limestone after a dozen cycles. - Abstract: The effect of the presence of HCl on cyclic CO2 capture behavior of calcium-based sorbent in the calcium looping process was investigated. When HCl was present in the carbonation atmosphere, the effects of carbonation temperature, calcination temperature, HCl concentration and particle size on CO2 capture of the limestone in the multiple calcination/carbonation cycles were studied in a dual fixed-bed reactor. The presence of HCl in the carbonation atmosphere improves CO2 capture capacity of the limestone in the previous a dozen cycles, but sharply decreases its reactivity with further increasing the cycle number above a dozen. The presence of HCl intensifies the effects of carbonation temperature and calcination temperature on CO2 capture capacity of the limestone. The optimum carbonation temperature and the feasible calcination temperature for cyclic CO2 capture of the limestone in the presence of HCl should be 700 °C and below 900 °C, respectively. The cyclic CO2 capture capacity of the limestone in the previous a dozen cycles achieves the maximum in the presence of 300 ppm HCl with increasing the HCl concentration from 100 to 1000 ppm. The higher CO2 capture capacity of the limestone is achieved with smaller particle size in the presence of HCl. The presence of HCl may destroy the compact CaCO3 product layer and it is beneficial to CO2 diffusion through the layer in the initial cycles. The chlorination conversion and the molten CaCl2–CaCO3 product layer thickness of the limestone in the presence of HCl increase with the number of calcination/carbonation cycles. It

  18. Carbon-Based Solid-State Calcium Ion-Selective Microelectrode and Scanning Electrochemical Microscopy: A Quantitative Study of pH-Dependent Release of Calcium Ions from Bioactive Glass.

    Science.gov (United States)

    Ummadi, Jyothir Ganesh; Downs, Corey J; Joshi, Vrushali S; Ferracane, Jack L; Koley, Dipankar

    2016-03-15

    Solid-state ion-selective electrodes are used as scanning electrochemical microscope (SECM) probes because of their inherent fast response time and ease of miniaturization. In this study, we report the development of a solid-state, low-poly(vinyl chloride), carbon-based calcium ion-selective microelectrode (Ca(2+)-ISME), 25 μm in diameter, capable of performing an amperometric approach curve and serving as a potentiometric sensor. The Ca(2+)-ISME has a broad linear response range of 5 μM to 200 mM with a near Nernstian slope of 28 mV/log[a(Ca(2+))]. The calculated detection limit for Ca(2+)-ISME is 1 μM. The selectivity coefficients of this Ca(2+)-ISME are log K(Ca(2+),A) = -5.88, -5.54, and -6.31 for Mg(2+), Na(+), and K(+), respectively. We used this new type of Ca(2+)-ISME as an SECM probe to quantitatively map the chemical microenvironment produced by a model substrate, bioactive glass (BAG). In acidic conditions (pH 4.5), BAG was found to increase the calcium ion concentration from 0.7 mM ([Ca(2+)] in artificial saliva) to 1.4 mM at 20 μm above the surface. In addition, a solid-state dual SECM pH probe was used to correlate the release of calcium ions with the change in local pH. Three-dimensional pH and calcium ion distribution mapping were also obtained by using these solid-state probes. The quantitative mapping of pH and Ca(2+) above the BAG elucidates the effectiveness of BAG in neutralizing and releasing calcium ions in acidic conditions. PMID:26861499

  19. [Discovering L-type calcium channels inhibitors of antihypertensive drugs based on drug repositioning].

    Science.gov (United States)

    Liang, Ying-xi; He, Yu-su; Jiang, Lu-di; Yue, Qiao-xin; Cui, Shuai; Bin, Li; Ye, Xiao-tong; Zhang, Xiao-hua; Zhang, Yang-ling

    2015-09-01

    This study was amid to construct the pharmacophore model of L-type calcium channel antagonist in the application of screening Drugbank and TCMD. This paper repositions the approved drugs resulting from virtual screening and discusses the relocation-based drug discovery methods, screening antihypertensive drugs with L-type calcium channel function from TCMD. Qualitative hypotheses wre generated by HipHop separately on the basis of 12 compounds with antagonistic action on L-type calcium channel expressed in rabbit cardiac muscle. Datebase searching method was used to evaluate the generated hypotheses. The optimum hypothesis was used to search Drugbank and TCMD. This paper repositions the approved drugs and evaluates the antihypertensive effect of the chemical constituent of traditional Chinese medicine resulting from virtual screening by the matching score and literature. The results showed that optimum qualitative hypothesis is with six features, which were two hydrogen-bond acceptors, four hydrophobic groups, and the CAI value of 2.78. Screening Drugbank achieves 93 approved drugs. Screening TCMD achieves 285 chemical constituents of traditional Chinese medicine. It was concluded that the hypothesis is reliable and can be used to screen datebase. The approved drugs resulting from virtual screening, such as pravastatin, are potentially L-type calcium channels inhibitors. The chemical constituents of traditional Chinese medicine, such as Arctigenin III and Arctigenin are potentially antihypertensive drugs. It indicates that Drug Repositioning based on hypothesis is possible. PMID:26983215

  20. [Discovering L-type calcium channels inhibitors of antihypertensive drugs based on drug repositioning].

    Science.gov (United States)

    Liang, Ying-xi; He, Yu-su; Jiang, Lu-di; Yue, Qiao-xin; Cui, Shuai; Bin, Li; Ye, Xiao-tong; Zhang, Xiao-hua; Zhang, Yang-ling

    2015-09-01

    This study was amid to construct the pharmacophore model of L-type calcium channel antagonist in the application of screening Drugbank and TCMD. This paper repositions the approved drugs resulting from virtual screening and discusses the relocation-based drug discovery methods, screening antihypertensive drugs with L-type calcium channel function from TCMD. Qualitative hypotheses wre generated by HipHop separately on the basis of 12 compounds with antagonistic action on L-type calcium channel expressed in rabbit cardiac muscle. Datebase searching method was used to evaluate the generated hypotheses. The optimum hypothesis was used to search Drugbank and TCMD. This paper repositions the approved drugs and evaluates the antihypertensive effect of the chemical constituent of traditional Chinese medicine resulting from virtual screening by the matching score and literature. The results showed that optimum qualitative hypothesis is with six features, which were two hydrogen-bond acceptors, four hydrophobic groups, and the CAI value of 2.78. Screening Drugbank achieves 93 approved drugs. Screening TCMD achieves 285 chemical constituents of traditional Chinese medicine. It was concluded that the hypothesis is reliable and can be used to screen datebase. The approved drugs resulting from virtual screening, such as pravastatin, are potentially L-type calcium channels inhibitors. The chemical constituents of traditional Chinese medicine, such as Arctigenin III and Arctigenin are potentially antihypertensive drugs. It indicates that Drug Repositioning based on hypothesis is possible.

  1. Correlation between inhibition of calcium—dependent apoptosis by cyclosporin A and calcium transportation in HL—60 cells

    Institute of Scientific and Technical Information of China (English)

    HUANGQIQING; MINGFANG; 等

    1996-01-01

    Both calcium ionophore A23187 and endoplasmic reticulum Ca2+-ATPase inhibitor thapsigargin (Tg) could increse intracellular free calcium concentration and induce apoptosis in some cell lines.In the present study,we found that HL-60 cells treated with A23187 (1μg/ml) for 4h or with Tg(0.5μg/ml) for 2h showed typical characteristics of apoptosis.Pretreatment with nontoxic concentration of cyclosporin A (CsA) (1μg/ml) could block these effects.Flow cytometric analysis of intracellular Ca2+ after staining with fluo-3 AM showed that CsA did not prevent the increase of intracellular calcium induced by A23187 or Tg,but it could maintain the high level of intracellular Ca2+ for a long time.These results suggest that CsA may prevent calcium-induced apoptosis by blocking the transportation of Ca2+ in HL-60 cells.

  2. Edge-based correlation image registration for multispectral imaging

    Science.gov (United States)

    Nandy, Prabal

    2009-11-17

    Registration information for images of a common target obtained from a plurality of different spectral bands can be obtained by combining edge detection and phase correlation. The images are edge-filtered, and pairs of the edge-filtered images are then phase correlated to produce phase correlation images. The registration information can be determined based on these phase correlation images.

  3. Adaptation of two different calcium hydroxide bases under a composite restoration.

    Science.gov (United States)

    Papadakou, M; Barnes, I E; Wassell, R W; McCabe, J F

    1990-10-01

    A preliminary scanning electron microscope (SEM) study was carried out to investigate how the adaptation of two calcium hydroxide bases (one chemically cured, one light cured) was affected by the polymerization contraction of a supervening light-cured composite resin restoration. Occlusal cavities were prepared in 40 sound extracted human premolars, divided into two equal groups. In the first group a chemically cured calcium hydroxide (Dycal, De Trey Dentsply, Konstanz, FRG) was placed as a base. In the second group a new light-cured calcium hydroxide product (Prisma VLC Dycal, De Trey Dentsply) was used. The restorations were completed with an acid-etched, incrementally placed composite resin. The specimens were sectioned vertically and debrided. A replica was made of each half-tooth. The interfaces between composite resin/base and base/dentine were viewed and photographed in the SEM. The marginal adaptation at these two interfaces was classified into three categories according to the extent of the gaps that were observed. Prisma VLC Dycal base was found to be pulled away from the dentine floor of the cavity as a result of an apparent adhesion to the composite resin during polymerization contraction. Dycal was better adapted to the cavity floor than Prisma VLC Dycal. Disorganization of the resin-bonded Prisma VLC Dycal was minimal even after acid etching the enamel, sectioning and ultrasonic debridement. Dycal appeared to be more friable, and occasionally exhibited marked disorganization as a result of these procedures.

  4. Are Eurozone Fixed Income Markets Integrated? An Analysis Based on Wavelet Multiple Correlation and Cross Correlation

    Directory of Open Access Journals (Sweden)

    Arif Billah Dar

    2014-01-01

    Full Text Available This paper investigates the synchronization of fixed income markets within Eurozone countries using the new wavelet based methodology. Conventional wavelet methods that use multivariate set of variables to calculate pairwise correlation and cross correlation lead to spurious correlation due to possible relationships with other variables, amplification of type-1 errors, and results, in the form of large set of erroneous graphs. Given these disadvantages of conventional wavelet based pairwise correlation and cross-correlation method, we avoid these limitations by using wavelet multiple correlation and multiple cross correlations to analyze the relationships in Eurozone fixed income markets. Our results based on this methodology indicate that Eurozone fixed income markets are highly integrated and this integration grows with timescales, and hence there is almost no scope for independent monetary policy and bond diversification in these countries.

  5. DSN Beowulf Cluster-Based VLBI Correlator

    Science.gov (United States)

    Rogstad, Stephen P.; Jongeling, Andre P.; Finley, Susan G.; White, Leslie A.; Lanyi, Gabor E.; Clark, John E.; Goodhart, Charles E.

    2009-01-01

    The NASA Deep Space Network (DSN) requires a broadband VLBI (very long baseline interferometry) correlator to process data routinely taken as part of the VLBI source Catalogue Maintenance and Enhancement task (CAT M&E) and the Time and Earth Motion Precision Observations task (TEMPO). The data provided by these measurements are a crucial ingredient in the formation of precision deep-space navigation models. In addition, a VLBI correlator is needed to provide support for other VLBI related activities for both internal and external customers. The JPL VLBI Correlator (JVC) was designed, developed, and delivered to the DSN as a successor to the legacy Block II Correlator. The JVC is a full-capability VLBI correlator that uses software processes running on multiple computers to cross-correlate two-antenna broadband noise data. Components of this new system (see Figure 1) consist of Linux PCs integrated into a Beowulf Cluster, an existing Mark5 data storage system, a RAID array, an existing software correlator package (SoftC) originally developed for Delta DOR Navigation processing, and various custom- developed software processes and scripts. Parallel processing on the JVC is achieved by assigning slave nodes of the Beowulf cluster to process separate scans in parallel until all scans have been processed. Due to the single stream sequential playback of the Mark5 data, some ramp-up time is required before all nodes can have access to required scan data. Core functions of each processing step are accomplished using optimized C programs. The coordination and execution of these programs across the cluster is accomplished using Pearl scripts, PostgreSQL commands, and a handful of miscellaneous system utilities. Mark5 data modules are loaded on Mark5 Data systems playback units, one per station. Data processing is started when the operator scans the Mark5 systems and runs a script that reads various configuration files and then creates an experiment-dependent status database

  6. A construction of novel iron-foam-based calcium phosphate/chitosan coating biodegradable scaffold material.

    Science.gov (United States)

    Wen, Zhaohui; Zhang, Liming; Chen, Chao; Liu, Yibo; Wu, Changjun; Dai, Changsong

    2013-04-01

    Slow corrosion rate and poor bioactivity restrict iron-based implants in biomedical application. In this study, we design a new iron-foam-based calcium phosphate/chitosan coating biodegradable composites offering a priority mechanical and bioactive property for bone tissue engineering through electrophoretic deposition (EPD) followed by a conversion process into a phosphate buffer solution (PBS). Tensile test results showed that the mechanical property of iron foam could be regulated through altering the construction of polyurethane foam. The priority coatings were deposited from 40% nano hydroxyapatite (nHA)/ethanol suspension mixed with 60% nHA/chitosan-acetic acid aqueous solution. In vitro immersion test showed that oxidation-iron foam as the matrix decreased the amount of iron implanted and had not influence on the bioactivity of this implant, obviously. So, this method could also be a promising method for the preparation of a new calcium phosphate/chitosan coating on foam construction. PMID:23827538

  7. A construction of novel iron-foam-based calcium phosphate/chitosan coating biodegradable scaffold material.

    Science.gov (United States)

    Wen, Zhaohui; Zhang, Liming; Chen, Chao; Liu, Yibo; Wu, Changjun; Dai, Changsong

    2013-04-01

    Slow corrosion rate and poor bioactivity restrict iron-based implants in biomedical application. In this study, we design a new iron-foam-based calcium phosphate/chitosan coating biodegradable composites offering a priority mechanical and bioactive property for bone tissue engineering through electrophoretic deposition (EPD) followed by a conversion process into a phosphate buffer solution (PBS). Tensile test results showed that the mechanical property of iron foam could be regulated through altering the construction of polyurethane foam. The priority coatings were deposited from 40% nano hydroxyapatite (nHA)/ethanol suspension mixed with 60% nHA/chitosan-acetic acid aqueous solution. In vitro immersion test showed that oxidation-iron foam as the matrix decreased the amount of iron implanted and had not influence on the bioactivity of this implant, obviously. So, this method could also be a promising method for the preparation of a new calcium phosphate/chitosan coating on foam construction.

  8. Trinocular Stereo Matching Based on Correlations Between Baselines and Disparities

    Institute of Scientific and Technical Information of China (English)

    GUANYepeng; GUWeikang

    2004-01-01

    Gray correlation technique is utilized to take the multi-peak feature points with gray correlation coefficients less than a certain range of maximal correlation coefficient as a potential candidate matching set. There exists the maximal correlation between the correct disparities and their corresponding baselines. A trinocular stereo matching algorithm is proposed based on correlations between the baselines and disparities. After computing the correlations between the baselines and disparities, the unique matches can be determined by maximal correlation coefficient. It is proved that the algorithm proposed is valid and credible by 3-D reconstruction on two pairs of actual natural stereo images.

  9. Subspace decomposition-based correlation matrix multiplication

    Institute of Scientific and Technical Information of China (English)

    Cheng Hao; Guo Wei; Yu Jingdong

    2008-01-01

    The correlation matrix, which is widely used in eigenvalue decomposition (EVD) or singular value decomposition (SVD), usually can be denoted by R = E[yiy'i]. A novel method for constructing the correlation matrix R is proposed. The proposed algorithm can improve the resolving power of the signal eigenvalues and overcomes the shortcomings of the traditional subspace methods, which cannot be applied to low SNR. Then the proposed method is applied to the direct sequence spread spectrum (DSSS) signal's signature sequence estimation.The performance of the proposed algorithm is analyzed, and some illustrative simulation results are presented.

  10. Solubility of a new calcium silicate-based root-end filling material

    OpenAIRE

    Shishir Singh; Rajesh Podar; Shifali Dadu; Gaurav Kulkarni; Rucheet Purba

    2015-01-01

    Introduction: The purpose of this study was to compare solubility of a new calcium silicate-based cement, Biodentine with three commonly used root-end filling materials viz. glass-ionomer cement (GIC), intermediate restorative material (IRM), and mineral trioxide aggregate (MTA). Materials and Methods: Twenty stainless steel ring molds were filled with cements corresponding to four groups (n = 5). The weight of 20 dried glass bottles was recorded. Samples were transferred to bottles conta...

  11. Cytotoxicity and genotoxicity of calcium silicate-based cements on an osteoblast lineage

    Directory of Open Access Journals (Sweden)

    Ana Lívia GOMES-CORNÉLIO

    2016-01-01

    Full Text Available Abstract Several calcium silicate-based biomaterials have been developed in recent years, in addition to Mineral Trioxide Aggregate (MTA. The aim of this study was to evaluate the cytotoxicity, genotoxicity and apoptosis/necrosis in human osteoblast cells (SAOS-2 of pure calcium silicate-based cements (CSC and modified formulations: modified calcium silicate-based cements (CSCM and three resin-based calcium silicate cements (CSCR1 (CSCR 2 (CSCR3. The following tests were performed after 24 hours of cement extract exposure: methyl-thiazolyl tetrazolium (MTT, apoptosis/necrosis assay and comet assay. The negative control (CT- was performed with untreated cells, and the positive control (CT+ used hydrogen peroxide. The data for MTT and apoptosis were submitted to analysis of variance and Bonferroni’s posttest (p < 0.05, and the data for the comet assay analysis, to the Kruskal-Wallis and Dunn tests (p < 0.05. The MTT test showed no significant difference among the materials in 2 mg/mL and 10 mg/mL concentrations. CSCR3 showed lower cell viability at 10 mg/mL. Only CSC showed lower cell viability at 50 mg/mL. CSCR1, CSCR2 and CSCR3 showed a higher percentage of initial apoptosis than the control in the apoptosis test, after 24 hours exposure. The same cements showed no genotoxicity in the concentration of 2 mg/mL, with the comet assay. CSC and CSCR2 were also not genotoxic at 10 mg/mL. All experimental materials showed viability with MTT. CSC and CSCR2 presented a better response to apoptosis and genotoxicity evaluation in the 10 mg/mL concentration, and demonstrated a considerable potential for use as reparative materials.

  12. Effects of changes in acid base and calcium concentration on fasting serum insulin, proinsulin, and glucose concentrations.

    OpenAIRE

    Smellie, W S; O'Donnell, J; Davidson, H.; Couper, J; Logue, F. C.

    1994-01-01

    AIMS--To test the hypothesis that alterations in acid base or calcium concentration may affect proinsulin processing or the insulin secretion mechanism. METHODS--Changes in proinsulin secretion or cleavage were assessed by measuring serum intact proinsulin and immunoreactive insulin concentrations in three models of acid base and calcium disturbance: (1) subacute changes in acid base status in six volunteers who received oral placebo, ammonium chloride, or sodium bicarbonate for three five da...

  13. A neuron-based screening platform for optimizing genetically-encoded calcium indicators.

    Directory of Open Access Journals (Sweden)

    Trevor J Wardill

    Full Text Available Fluorescent protein-based sensors for detecting neuronal activity have been developed largely based on non-neuronal screening systems. However, the dynamics of neuronal state variables (e.g., voltage, calcium, etc. are typically very rapid compared to those of non-excitable cells. We developed an electrical stimulation and fluorescence imaging platform based on dissociated rat primary neuronal cultures. We describe its use in testing genetically-encoded calcium indicators (GECIs. Efficient neuronal GECI expression was achieved using lentiviruses containing a neuronal-selective gene promoter. Action potentials (APs and thus neuronal calcium levels were quantitatively controlled by electrical field stimulation, and fluorescence images were recorded. Images were segmented to extract fluorescence signals corresponding to individual GECI-expressing neurons, which improved sensitivity over full-field measurements. We demonstrate the superiority of screening GECIs in neurons compared with solution measurements. Neuronal screening was useful for efficient identification of variants with both improved response kinetics and high signal amplitudes. This platform can be used to screen many types of sensors with cellular resolution under realistic conditions where neuronal state variables are in relevant ranges with respect to timing and amplitude.

  14. Structural characterization of anion-calcium-humate complexes in phosphate-based fertilizers.

    Science.gov (United States)

    Baigorri, Roberto; Urrutia, Oscar; Erro, Javier; Mandado, Marcos; Pérez-Juste, Ignacio; Garcia-Mina, José María

    2013-07-01

    Fertilizers based on phosphate-metal-humate complexes are a new family of compounds that represents a more sustainable and bioavailable phosphorus source. The characterization of this type of complex by using solid (31)P NMR in several fertilizers, based on single superphosphate (SSP) and triple superphosphate (TSP) matrices, yielded surprising and unexpected trends in the intensity and fine structure of the (31)P NMR peaks. Computational chemistry methods allowed the characterization of phosphate-calcium-humate complexes in both SSP and TSP matrices, but also predicted the formation of a stable sulfate-calcium-humate complex in the SSP fertilizers, which has not been described previously. The stability of this complex has been confirmed by using ultrafiltration techniques. Preference towards the humic substance for the sulfate-metal phase in SSP allowed the explanation of the opposing trends that were observed in the experimental (31)P NMR spectra of SSP and TSP samples. Additionally, computational chemistry has provided an assignment of the (31)P NMR signals to different phosphate ligands as well as valuable information about the relative strength of the phosphate-calcium interactions within the crystals.

  15. Structural characterization of anion-calcium-humate complexes in phosphate-based fertilizers.

    Science.gov (United States)

    Baigorri, Roberto; Urrutia, Oscar; Erro, Javier; Mandado, Marcos; Pérez-Juste, Ignacio; Garcia-Mina, José María

    2013-07-01

    Fertilizers based on phosphate-metal-humate complexes are a new family of compounds that represents a more sustainable and bioavailable phosphorus source. The characterization of this type of complex by using solid (31)P NMR in several fertilizers, based on single superphosphate (SSP) and triple superphosphate (TSP) matrices, yielded surprising and unexpected trends in the intensity and fine structure of the (31)P NMR peaks. Computational chemistry methods allowed the characterization of phosphate-calcium-humate complexes in both SSP and TSP matrices, but also predicted the formation of a stable sulfate-calcium-humate complex in the SSP fertilizers, which has not been described previously. The stability of this complex has been confirmed by using ultrafiltration techniques. Preference towards the humic substance for the sulfate-metal phase in SSP allowed the explanation of the opposing trends that were observed in the experimental (31)P NMR spectra of SSP and TSP samples. Additionally, computational chemistry has provided an assignment of the (31)P NMR signals to different phosphate ligands as well as valuable information about the relative strength of the phosphate-calcium interactions within the crystals. PMID:23670945

  16. Designing calcium phosphate-based bifunctional nanocapsules with bone-targeting properties

    Energy Technology Data Exchange (ETDEWEB)

    Khung, Yit-Lung; Bastari, Kelsen; Cho, Xing Ling; Yee, Wu Aik; Loo, Say Chye Joachim, E-mail: joachimloo@ntu.edu.sg [Nanyang Technological University, School of Materials Science and Engineering (Singapore)

    2012-06-15

    Using sodium dodecyl sulphate micelles as template, hollow-cored calcium phosphate nanocapsules were produced. The surfaces of the nanocapsule were subsequently silanised by a polyethylene glycol (PEG)-based silane with an N-hydroxysuccinimide ester end groups which permits for further attachment with bisphosphonates (BP). Characterisations of these nanocapsules were investigated using Field Emission Scanning Electron Microscopy (FESEM), Transmission Electron Microscopy, Fourier Transform Infra-Red Spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and Dynamic Light Scattering. To further validate the bone-targeting potential, dentine discs were incubated with these functionalised nanocapsules. FESEM analysis showed that these surface-modified nanocapsules would bind strongly to dentine surfaces compared to non-functionalised nanocapsules. We envisage that respective components would give this construct a bifunctional attribute, whereby (1) the shell of the calcium phosphate nanocapsule would serve as biocompatible coating aiding in gradual osteoconduction, while (2) surface BP moieties, acting as targeting ligands, would provide the bone-targeting potential of these calcium phosphate nanocapsules.

  17. Collaborative Filtering Algorithms Based on Kendall Correlation in Recommender Systems

    Institute of Scientific and Technical Information of China (English)

    YAO Yu; ZHU Shanfeng; CHEN Xinmeng

    2006-01-01

    In this work, Kendall correlation based collaborative filtering algorithms for the recommender systems are proposed. The Kendall correlation method is used to measure the correlation amongst users by means of considering the relative order of the users' ratings. Kendall based algorithm is based upon a more general model and thus could be more widely applied in e-commerce. Another discovery of this work is that the consideration of only positive correlated neighbors in prediction, in both Pearson and Kendall algorithms, achieves higher accuracy than the consideration of all neighbors, with only a small loss of coverage.

  18. Asymptotic distributions in the projection pursuit based canonical correlation analysis

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In this paper, associations between two sets of random variables based on the projection pursuit (PP) method are studied. The asymptotic normal distributions of estimators of the PP based canonical correlations and weighting vectors are derived.

  19. Research on a Diagnosis Method Based on a Correlation Integral

    Institute of Scientific and Technical Information of China (English)

    ZHAO Hong; XIA Yong; LIANG Xiao-guo

    2003-01-01

    For the first time, the diagnosis idea based on a correlation integral is proposed, which regards the correlation integral as a feature set. The correlation dimension is contained in the double-log curve of the correlation integral to scale, so extracting features directly from the correlation integral can avoid the bottleneck problem of determining the range of non-scale length. Several features extracted from the correlation integral are better than the single feature of the correlation dimension when descri bing the signal. It is obvious that this method utilizes more information of the signal than does the correlation dimension. The diagnosis examples verify that this method is more accurate and more effective.

  20. Hair Mercury Negatively Correlates with Calcium Pump Activity in Human Term Newborns and Their Mothers at Delivery

    OpenAIRE

    Huel, Guy; Sahuquillo, Josiane; Debotte, Ginette; Oury, Jean-François; Takser, Larissa

    2007-01-01

    Background Calcium homeostasis is a known target of several environmental toxicants including lead and mercury. Objective Our goal was to determine the relationship between Hg exposure and erythrocyte Ca pump activity in women at delivery and in their newborns. Methods We determined total Hg as well as Pb concentrations in 81 hair and blood samples obtained at delivery. Basal and calmodulin-stimulated Ca pump activity was measured in red blood cells from cord blood and maternal erythrocyte pl...

  1. Evolution of worldwide stock markets, correlation structure, and correlation-based graphs

    Science.gov (United States)

    Song, Dong-Ming; Tumminello, Michele; Zhou, Wei-Xing; Mantegna, Rosario N.

    2011-08-01

    We investigate the daily correlation present among market indices of stock exchanges located all over the world in the time period January 1996 to July 2009. We discover that the correlation among market indices presents both a fast and a slow dynamics. The slow dynamics reflects the development and consolidation of globalization. The fast dynamics is associated with critical events that originate in a specific country or region of the world and rapidly affect the global system. We provide evidence that the short term time scale of correlation among market indices is less than 3 trading months (about 60 trading days). The average values of the nondiagonal elements of the correlation matrix, correlation-based graphs, and the spectral properties of the largest eigenvalues and eigenvectors of the correlation matrix are carrying information about the fast and slow dynamics of the correlation of market indices. We introduce a measure of mutual information based on link co-occurrence in networks in order to detect the fast dynamics of successive changes of correlation-based graphs in a quantitative way.

  2. Evolution of worldwide stock markets, correlation structure, and correlation-based graphs.

    Science.gov (United States)

    Song, Dong-Ming; Tumminello, Michele; Zhou, Wei-Xing; Mantegna, Rosario N

    2011-08-01

    We investigate the daily correlation present among market indices of stock exchanges located all over the world in the time period January 1996 to July 2009. We discover that the correlation among market indices presents both a fast and a slow dynamics. The slow dynamics reflects the development and consolidation of globalization. The fast dynamics is associated with critical events that originate in a specific country or region of the world and rapidly affect the global system. We provide evidence that the short term time scale of correlation among market indices is less than 3 trading months (about 60 trading days). The average values of the nondiagonal elements of the correlation matrix, correlation-based graphs, and the spectral properties of the largest eigenvalues and eigenvectors of the correlation matrix are carrying information about the fast and slow dynamics of the correlation of market indices. We introduce a measure of mutual information based on link co-occurrence in networks in order to detect the fast dynamics of successive changes of correlation-based graphs in a quantitative way.

  3. Novel microwell-based spectrophotometric assay for determination of atorvastatin calcium in its pharmaceutical formulations

    Directory of Open Access Journals (Sweden)

    Abdel-Rahman Hamdy M

    2011-10-01

    Full Text Available Abstract The formation of a colored charge-transfer (CT complex between atorvastatin calcium (ATR-Ca as a n-electron donor and 2, 3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ as a π-electron acceptor was investigated, for the first time. The spectral characteristics of the CT complex have been described, and the reaction mechanism has been proved by computational molecular modeling. The reaction was employed in the development of a novel microwell-based spectrophotometric assay for determination of ATR-Ca in its pharmaceutical formulations. The proposed assay was carried out in 96-microwell plates. The absorbance of the colored-CT complex was measured at 460 nm by microwell-plate absorbance reader. The optimum conditions of the reaction and the analytical procedures of the assay were established. Under the optimum conditions, linear relationship with good correlation coefficient (0.9995 was found between the absorbance and the concentration of ATR-Ca in the range of 10-150 μg/well. The limits of detection and quantitation were 5.3 and 15.8 μg/well, respectively. No interference was observed from the additives that are present in the pharmaceutical formulation or from the drugs that are co-formulated with ATR-Ca in its combined formulations. The assay was successfully applied to the analysis of ATR-Ca in its pharmaceutical dosage forms with good accuracy and precision. The assay described herein has great practical value in the routine analysis of ATR-Ca in quality control laboratories, as it has high throughput property, consumes minimum volume of organic solvent thus it offers the reduction in the exposures of the analysts to the toxic effects of organic solvents, and reduction in the analysis cost by 50-fold. Although the proposed assay was validated for ATR-Ca, however, the same methodology could be used for any electron-donating analyte for which a CT reaction can be performed.

  4. Differential neuronal targeting of a new and two known calcium channel β4 subunit splice variants correlates with their regulation of gene expression.

    Science.gov (United States)

    Etemad, Solmaz; Obermair, Gerald J; Bindreither, Daniel; Benedetti, Ariane; Stanika, Ruslan; Di Biase, Valentina; Burtscher, Verena; Koschak, Alexandra; Kofler, Reinhard; Geley, Stephan; Wille, Alexandra; Lusser, Alexandra; Flockerzi, Veit; Flucher, Bernhard E

    2014-01-22

    The β subunits of voltage-gated calcium channels regulate surface expression and gating of CaV1 and CaV2 α1 subunits and thus contribute to neuronal excitability, neurotransmitter release, and calcium-induced gene regulation. In addition, certain β subunits are targeted into the nucleus, where they interact directly with the epigenetic machinery. Whereas their involvement in this multitude of functions is reflected by a great molecular heterogeneity of β isoforms derived from four genes and abundant alternative splicing, little is known about the roles of individual β variants in specific neuronal functions. In the present study, an alternatively spliced β4 subunit lacking the variable N terminus (β4e) is identified. It is highly expressed in mouse cerebellum and cultured cerebellar granule cells (CGCs) and modulates P/Q-type calcium currents in tsA201 cells and CaV2.1 surface expression in neurons. Compared with the other two known full-length β4 variants (β4a and β4b), β4e is most abundantly expressed in the distal axon, but lacks nuclear-targeting properties. To determine the importance of nuclear targeting of β4 subunits for transcriptional regulation, we performed whole-genome expression profiling of CGCs from lethargic (β4-null) mice individually reconstituted with β4a, β4b, and β4e. Notably, the number of genes regulated by each β4 splice variant correlated with the rank order of their nuclear-targeting properties (β4b > β4a > β4e). Together, these findings support isoform-specific functions of β4 splice variants in neurons, with β4b playing a dual role in channel modulation and gene regulation, whereas the newly detected β4e variant serves exclusively in calcium-channel-dependent functions. PMID:24453333

  5. Quantitative Evaluation by Glucose Diffusion of Microleakage in Aged Calcium Silicate-Based Open-Sandwich Restorations

    OpenAIRE

    Camps, J.; Tassery, H.; Koubi, G.; Elmerini, H.; Koubi, S.

    2012-01-01

    This study compared the in vitro marginal integrity of open-sandwich restorations based on aged calcium silicate cement versus resin-modified glass ionomer cement. Class II cavities were prepared on 30 extracted human third molars. These teeth were randomly assigned to two groups ( = 1 0 ) to compare a new hydraulic calcium silicate cement designed for restorative dentistry (Biodentine, Septodont, Saint Maur des Fossés, France) with a resin-modified glass ionomer cement (Ionolux, Voco, Cuxh...

  6. Structuralization of Ca(2+)-Based Metal-Organic Frameworks Prepared via Coordination Replication of Calcium Carbonate.

    Science.gov (United States)

    Sumida, Kenji; Hu, Ming; Furukawa, Shuhei; Kitagawa, Susumu

    2016-04-01

    The emergence of metal-organic frameworks (MOFs) as potential candidates to supplant existing adsorbent types in real-world applications has led to an explosive growth in the number of compounds available to researchers, as well as in the diversity of the metal salts and organic linkers from which they are derived. In this context, the use of carbonate-based precursors as metal sources is of interest due to their abundance in mineral deposits and their reaction chemistry with acids, resulting in just water and carbon dioxide as side products. Here, we have explored the use of calcium carbonate as a metal source and demonstrate its versatility as a precursor to several known frameworks, as well as a new flexible compound based on the 2,5-dihydroxybenzoquinone (H2dhbq) linker, Ca(dhbq)(H2O)2. Furthermore, inspired by the ubiquity and unique structures of biomineralized forms of calcium carbonate, we also present examples of the preparation of superstructures of Ca-based MOFs via the coordination replication technique. In all, the results confirm the suitability of carbonate-based metal sources for the preparation of MOFs and further expand upon the growing scope of coordination replication as a convenient strategy for the preparation of structuralized materials. PMID:27002690

  7. Nanotubes from Oxide-Based Misfit Family: The Case of Calcium Cobalt Oxide.

    Science.gov (United States)

    Panchakarla, Leela S; Lajaunie, Luc; Ramasubramaniam, Ashwin; Arenal, Raul; Tenne, Reshef

    2016-06-28

    Misfit layered compounds (MLCs) have generated significant interest in recent years as potential thermoelectric materials. MLC nanotubes could reveal behavior that is entirely different from the bulk material. Recently, new chemical strategies were exploited for the synthesis of nanotubular forms of chalcogenide-based MLCs, which are promising candidates for thermoelectric materials. However, analogous synthesis of oxide-based MLC nanotubes has not been demonstrated until now. Here, we report a chemical strategy for synthesis of cobalt-oxide-based misfit nanotubes. A combination of high-resolution (scanning) transmission electron microscopy (including image simulations), spatially resolved electron energy-loss spectroscopy, electron diffraction, and density functional theory (DFT) calculations is used to discover the formation of a phase within these nanotubes that differs significantly from bulk calcium cobaltite MLCs. Furthermore, DFT calculations show that this phase is semiconducting with a band gap in excess of 1 eV, unlike bulk calcium cobaltite MLCs, which are known to be metallic. Through systematic experiments, we propose a formation mechanism for these nanotubes that could also apply more generally to realizing other oxide-based MLC nanotubes. PMID:27215812

  8. Biocompatibility and bioactivity of calcium silicate-based endodontic sealers in human dental pulp cells

    Directory of Open Access Journals (Sweden)

    Leticia Boldrin MESTIERI

    2015-10-01

    Full Text Available Mineral Trioxide Aggregate (MTA is a calcium silicate-based material. New sealers have been developed based on calcium silicate as MTA Fillapex and MTA Plus.Objective The aim of this study was to evaluate biocompatibility and bioactivity of these two calcium silicate-based sealers in culture of human dental pulp cells (hDPCs.Material and Methods The cells were isolated from third molars extracted from a 16-year-old patient. Pulp tissue was sectioned into fragments with approximately 1 mm3 and kept in supplemented medium to obtain hDPCs adherent cultures. Cell characterization assays were performed to prove the osteogenic potential. The evaluated materials were: MTA Plus (MTAP; MTA Fillapex (MTAF and FillCanal (FC. Biocompatibility was evaluated with MTT and Neutral Red (NR assays, after hDPCs exposure for 24 h to different dilutions of each sealer extract (1:2, 1:3 and 1:4. Unexposed cells were the positive control (CT. Bioactivity was assessed by alkaline phosphatase (ALP enzymatic assay in cells exposed for one and three days to sealer extracts (1:4 dilution. All data were analyzed by ANOVA and Tukey post-test (p≤0.05%.Results MTT and NR results showed suitable cell viability rates for MTAP at all dilutions (90-135%. Cells exposed to MTAF and FC (1:2 and 1:4 dilutions showed significant low viability rate when compared to CT in MTT. The NR results demonstrated cell viability for all materials tested. In MTAP group, the cells ALP activity was similar to CT in one and three days of exposure to the material. MTAF and FC groups demonstrated a decrease in ALP activity when compared to CT at both periods of cell exposure.Conclusions The hDPCs were suitable for the evaluation of new endodontic materialsin vitro. MTAP may be considered a promising material for endodontic treatments.

  9. Effect of calcium on adsorptive removal of As(III) and As(V) by iron oxide-based adsorbents

    KAUST Repository

    Uwamariya, V.

    2014-06-25

    The effects of calcium on the equilibrium adsorption capacity of As(III) and As(V) onto iron oxide-coated sand (IOCS) and granular ferric hydroxide (GFH) were investigated through batch experiments, rapid small-scale column tests (RSSCT) and kinetics modelling. Batch experiments showed that at calcium concentrations≤20 mg/L, high As(III) and As(V) removal efficiencies by IOCS and GFH are achieved at pH 6. An increase of the calcium concentration to 40 and 80 mg/L reversed this trend, giving higher removal efficiencies at higher pH (8). The adsorption capacities of IOCS and GFH at an equilibrium arsenic concentration of 10 g/L were found to be between 2.0 and 3.1 mg/g for synthetic water without calcium and between 2.8 and 5.3 mg/g when 80 mg/L of calcium was present at the studied pH values. After 10 hours of filter run in RSSCT, approximately 1000 empty bed volumes, the ratios of C/Co for As(V) were 26% and 18% for calcium-free model water; and only 1% and 0.2% after addition of 80 mg/L of Ca for filter columns with IOCS and GFH, respectively. The adsorption of As(III) and As(V) onto GFH follows a second-order reaction, with and without addition of calcium. The adsorption of As(III) and As(V) onto IOCS follows a first-order reaction without calcium addition, and moves to the second-reaction-order kinetics when calcium is added. Based on the intraparticle diffusion model, the main controlling mechanism for As(III) adsorption is intraparticle diffusion, while surface diffusion contributes greatly to the adsorption of As(V).

  10. Non Correlation DWT Based Watermarking Behavior in Different Color Spaces

    Directory of Open Access Journals (Sweden)

    Mehdi Khalili

    2016-01-01

    Full Text Available There are two digital watermarking techniques. Digital watermarking techniques based on correlation and digital watermarking techniques that are not based on correlation. In previous work, we proposed a DWT2 based CDMA image watermarking scheme to study the effects of using eight color spaces RGB, YCbCr, JPEG-YCbCr, YIQ, YUV, HSI, HSV and CIELab, on watermarking algorithms based on correlation techniques. This paper proposes a non correlation based image watermarking scheme in wavelet transform domain and tests it in the same color spaces, to develop studying, reach a comprehensive analysis and focus on satisfying the requirements of based non coloration watermarking algorithms. To achieve more security, imperceptibility and robustness of the proposed scheme, first, the binary watermark image encodes by applying ATM, CCM and exclusive OR. Then, the scrambled watermark embeds into intended quantized approximation coefficients of wavelet transform by LSB insertion technique.

  11. DIHYDROPYRIDINE CALCIUM ANTAGONISTS: DATA OF EVIDENCE BASED MEDICINE AND RECOM-MENDATIONS ON PRACTICAL USE

    Directory of Open Access Journals (Sweden)

    S. Y. Martsevich

    2015-12-01

    Full Text Available The classification of calcium antagonists is presented. There were considered the results of large randomized trials, which were devoted to study of influence of dihydropyridine calcium antagonists on the risk of cardiovascular complications. The place of dihydropyridine calcium antagonists in modern recommendations on treatment of arterial hypertension and ischemic heart disease is defined. The clinical importance of differences between various presentations of dihy-dropyridine calcium antagonists is stressed.

  12. Effects of Leaching Behavior of Calcium Ions on Compression and Durability of Cement-based Materials with Mineral Admixtures

    Directory of Open Access Journals (Sweden)

    Wei-Ting Lin

    2013-05-01

    Full Text Available Leaching of calcium ions increases the porosity of cement-based materials, consequently resulting in a negative effect on durability since it provides an entry for aggressive harmful ions, causing reinforcing steel corrosion. This study investigates the effects of leaching behavior of calcium ions on the compression and durability of cement-based materials. Since the parameters influencing the leaching behavior of cement-based materials are unclear and diverse, this paper focuses on the influence of added mineral admixtures (fly ash, slag and silica fume on the leaching behavior of calcium ions regarding compression and durability of cemented-based materials. Ammonium nitrate solution was used to accelerate the leaching process in this study. Scanning electron microscopy, X-ray diffraction analysis, and thermogravimetric analysis were employed to analyze and compare the cement-based material compositions prior to and after calcium ion leaching. The experimental results show that the mineral admixtures reduce calcium hydroxide quantity and refine pore structure through pozzolanic reaction, thus enhancing the compressive strength and durability of cement-based materials.

  13. WAVELET BASED SPECTRAL CORRELATION METHOD FOR DPSK CHIP RATE ESTIMATION

    Institute of Scientific and Technical Information of China (English)

    Li Yingxiang; Xiao Xianci; Tai Hengming

    2004-01-01

    A wavelet-based spectral correlation algorithm to detect and estimate BPSK signal chip rate is proposed. Simulation results show that the proposed method can correctly estimate the BPSK signal chip rate, which may be corrupted by the quadratic characteristics of the spectral correlation function, in a low SNR environment.

  14. Quantum Encryption Protocol Based on Continuous Variable EPR Correlations

    Institute of Scientific and Technical Information of China (English)

    HE Guang-Qiang; ZENG Gui-Hua

    2006-01-01

    A quantum encryption protocol based on Gaussian-modulated continuous variable EPR correlations is proposed. The security is guaranteed by continuous variable EPR entanglement correlations produced by nondegenerate optical parametric amplifier (NOPA). For general beam splitter eavesdropping strategy, the mutual information Ⅰ(α, ε)between Alice and Eve is calculated by employing Shannon information theory. Finally the security analysis is presented.

  15. Biocompatibility of a new nanomaterial based on calcium silicate implanted in subcutaneous connective tissue of rats

    Directory of Open Access Journals (Sweden)

    Petrović Violeta

    2012-01-01

    Full Text Available The aim of the study was to investigate rat connective tissue response to a new calcium silicate system 7, 15, 30 and 60 days after implantation. Twenty Wistar albino male rats received two tubes half-filled with a new calcium silicate system (NCSS or MTA in subcutaneous tissue. The empty half of the tubes served as controls. Five animals were sacrificed after 7, 15, 30 and 60 days and samples of the subcutaneous tissue around implanted material were submitted to histological analysis. The intensity of inflammation was evaluated based on the number of inflammatory cells present. Statistical analysis was performed using one way ANOVA and Holm Sidak's multiple comparison tests. Mild to moderate inflammatory reaction was observed after 7, 15 and 30 days around a NCSS while mild inflammatory reaction was detected after 60 days of implantation. In the MTA group, mild to moderate inflammatory reaction was found after 7 and 15 days while mild inflammatory reaction was present after 30 and 60 days. There was no statistically significant difference in the intensity of inflammatory reactions between the tested materials and control groups in any experimental period (ANOVA p>0.05. Regarding the intensity of inflammatory reactions at different experimental periods, a statistically significant difference was observed between 7 and 30 days, 7 and 60 days and 15 to 60 days for both materials. For the controls, a statistically significant difference was found between 7 and 60 days and 15 and 60 days of the experiment (Holm Sidak < p 0.001. Subcutaneous tissue of rats showed good tolerance to a new calcium silicate system. Inflammatory reaction was similar to that caused by MTA. [Projekat Ministarstva nauke Republike Srbije, br. 172026

  16. [Study on the Influence of Mineralizer on the Preparation of Calcium Aluminates Based on Infrared Spectroscopy].

    Science.gov (United States)

    Fan, Wei; Wang, Liang; Zheng, Huai-li; Chen, Wei; Tang, Xiao-min; Shang, Juan-fang; Qian, Li

    2015-05-01

    In this study, effect of mineralizer on the structure and spectraproperties of calcium aluminates formation was extensively studied. Medium or low-grade bauxite and calcium carbonate were used as raw material and mineralizer CaF2 as additive. Calcium aluminates can be obtained after mixing fully, calcination and grinding. The prepared calcium aluminates can be directly used for the production of polyaluminiumchloride (PAC), polymeric aluminum sulfate, sodium aluminate and some other water treatment agents. The calcium aluminates preparation technology was optimized by investigating the mass ratio of raw materials (bauxiteand calcium carbonate) and mineralizer CaF2 dosage. The structure and spectra properties of bauxite and calcium aluminates were characterized by Fourier transform infrared(FTIR) spectroscopy analysis and the mineralization mechanism of the mineralizer was studied. FTIR spectra indicated that the addition of mineralizer promoted the decomposition and transformation of the diaspore, gibbsite and kaolinite, the decomposition of calcium carbonate, and more adequately reaction between bauxite and calcium carbonate. In addition, not only Ca in calcium carbonate and Si in bauxite were more readily reacted, but also Si-O, Si-O-Al and Al-Si bonds in the bauxite were more fractured which contributed to the release of Al in bauxite, and therefore, the dissolution rate of Al2O3 could be improved. The dissolution rate of Al2O3 can be promoted effectively when the mineralizer CaF2 was added in a mass ratio amount of 3%. And the mineralizer CaF2 cannot be fully functioned, when its dosage was in a mass percent of 1. 5%. Low-grade bauxite was easier to sinter for the preparation of calcium aluminates comparing with the highgrade one. The optimum material ratio for the preparation of calcium aluminates calcium at 1 250 °C was the mass ratio between bauxite and calcium carbonate of 1 : 0. 6 and mineralizer CaF2 mass ratio percent of 3%. PMID:26415430

  17. Dual energy x-ray imaging and scoring of coronary calcium: physics-based digital phantom and clinical studies

    Science.gov (United States)

    Zhou, Bo; Wen, Di; Nye, Katelyn; Gilkeson, Robert C.; Wilson, David L.

    2016-03-01

    Coronary artery calcification (CAC) as assessed with CT calcium score is the best biomarker of coronary artery disease. Dual energy x-ray provides an inexpensive, low radiation-dose alternative. A two shot system (GE Revolution-XRd) is used, raw images are processed with a custom algorithm, and a coronary calcium image (DECCI) is created, similar to the bone image, but optimized for CAC visualization, not lung visualization. In this report, we developed a physicsbased, digital-phantom containing heart, lung, CAC, spine, ribs, pulmonary artery, and adipose elements, examined effects on DECCI, suggested physics-inspired algorithms to improve CAC contrast, and evaluated the correlation between CT calcium scores and a proposed DE calcium score. In simulation experiment, Beam hardening from increasing adipose thickness (2cm to 8cm) reduced Cg by 19% and 27% in 120kVp and 60kVp images, but only reduced Cg by <7% in DECCI. If a pulmonary artery moves or pulsates with blood filling between exposures, it can give rise to a significantly confounding PA signal in DECCI similar in amplitude to CAC. Observations suggest modifications to DECCI processing, which can further improve CAC contrast by a factor of 2 in clinical exams. The DE score had the best correlation with "CT mass score" among three commonly used CT scores. Results suggest that DE x-ray is a promising tool for imaging and scoring CAC, and there still remains opportunity for further DECCI processing improvements.

  18. Chlorhexidine-calcium phosphate nanoparticles - Polymer mixer based wound healing cream and their applications.

    Science.gov (United States)

    Viswanathan, Kaliyaperumal; Monisha, P; Srinivasan, M; Swathi, D; Raman, M; Dhinakar Raj, G

    2016-10-01

    In this work, we developed a wound healing cream composed of two different polymers, namely chitosan and gelatin with chlorhexidine along with calcium phosphate nanoparticles. The physicochemical properties of the prepared cream were investigated based on SEM, EDX, Raman, FTIR and the results indicated that the cream contained gelatin, chitosan, calcium phosphate nanoparticles and chlorhexidine. The maximum swelling ratio studies indicated that the ratio was around of 52±2.2 at pH7.4 and the value was increased in acidic and alkaline pH. The antimicrobial activity was tested against bacteria and the results indicated that, both chlorhexidine and the hybrid cream devoid of chlorhexidine exhibited antimicrobial activity but the chlorhexidine impregnated cream showed three fold higher antimicrobial activity than without chlorhexidine. In vivo wound healing promoting activities of hybrid cream containing 0.4mg/L chlorhexidine were evaluated on surgically induced dermal wounds in mice. The results indicated that the cream with incorporated chlorhexidine significantly enhanced healing compared with the control samples. For the field validations, the veterinary clinical animals were treated with the cream and showed enhanced healing capacity. In conclusion, a simple and efficient method for design of a novel wound healing cream has been developed for veterinary applications.

  19. Chlorhexidine-calcium phosphate nanoparticles - Polymer mixer based wound healing cream and their applications.

    Science.gov (United States)

    Viswanathan, Kaliyaperumal; Monisha, P; Srinivasan, M; Swathi, D; Raman, M; Dhinakar Raj, G

    2016-10-01

    In this work, we developed a wound healing cream composed of two different polymers, namely chitosan and gelatin with chlorhexidine along with calcium phosphate nanoparticles. The physicochemical properties of the prepared cream were investigated based on SEM, EDX, Raman, FTIR and the results indicated that the cream contained gelatin, chitosan, calcium phosphate nanoparticles and chlorhexidine. The maximum swelling ratio studies indicated that the ratio was around of 52±2.2 at pH7.4 and the value was increased in acidic and alkaline pH. The antimicrobial activity was tested against bacteria and the results indicated that, both chlorhexidine and the hybrid cream devoid of chlorhexidine exhibited antimicrobial activity but the chlorhexidine impregnated cream showed three fold higher antimicrobial activity than without chlorhexidine. In vivo wound healing promoting activities of hybrid cream containing 0.4mg/L chlorhexidine were evaluated on surgically induced dermal wounds in mice. The results indicated that the cream with incorporated chlorhexidine significantly enhanced healing compared with the control samples. For the field validations, the veterinary clinical animals were treated with the cream and showed enhanced healing capacity. In conclusion, a simple and efficient method for design of a novel wound healing cream has been developed for veterinary applications. PMID:27287150

  20. In Vitro Cytotoxicity of Calcium Silicate-Based Endodontic Cement as Root-End Filling Materials

    Directory of Open Access Journals (Sweden)

    Selen Küçükkaya

    2016-01-01

    Full Text Available The aim of this study was to evaluate the cytotoxicity of three types of calcium silicate-based endodontic cement after different incubation periods with human periodontal ligament fibroblasts. Human periodontal ligament fibroblasts were cultured from extracted third molars and seeded in 96-well plates. MTA, calcium enriched mixture (CEM cement, and Biodentine were prepared and added to culture insert plates which were immediately placed into 96-well plates containing cultured cells. After incubation periods of 24, 48, and 72 hours, cell viability was determined with WST-1 assay. Data were analysed statistically by ANOVA with repeated measures and Bonferroni tests. There was no significant difference in cell viability amongst the test materials after each incubation period (P>0.05. MTA and CEM presented more than 90% cell viability after 24 and 48 hours of incubation and showed statistically significant decrease in cell viability after 72 hours of incubation (P<0.05. Biodentine showed significantly less cell viability (73% after 24 hours of incubation, whereas more than 90% cell viability was seen after 48 and 72 hours of incubation (P<0.05. Despite the significant changes in cell viability over time, materials presented similar cytotoxicity profile. Biodentine and CEM can be considered as alternative materials for root-end surgery procedures.

  1. In Vitro Cytotoxicity of Calcium Silicate-Based Endodontic Cement as Root-End Filling Materials.

    Science.gov (United States)

    Küçükkaya, Selen; Görduysus, Mehmet Ömer; Zeybek, Naciye Dilara; Müftüoğlu, Sevda Fatma

    2016-01-01

    The aim of this study was to evaluate the cytotoxicity of three types of calcium silicate-based endodontic cement after different incubation periods with human periodontal ligament fibroblasts. Human periodontal ligament fibroblasts were cultured from extracted third molars and seeded in 96-well plates. MTA, calcium enriched mixture (CEM) cement, and Biodentine were prepared and added to culture insert plates which were immediately placed into 96-well plates containing cultured cells. After incubation periods of 24, 48, and 72 hours, cell viability was determined with WST-1 assay. Data were analysed statistically by ANOVA with repeated measures and Bonferroni tests. There was no significant difference in cell viability amongst the test materials after each incubation period (P > 0.05). MTA and CEM presented more than 90% cell viability after 24 and 48 hours of incubation and showed statistically significant decrease in cell viability after 72 hours of incubation (P Biodentine showed significantly less cell viability (73%) after 24 hours of incubation, whereas more than 90% cell viability was seen after 48 and 72 hours of incubation (P Biodentine and CEM can be considered as alternative materials for root-end surgery procedures.

  2. Existence problem of optical correlation based pattern recognition

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Yanxin(张延炘); LI; Sumei(李素梅)

    2003-01-01

    The existence problem of optical correlation based pattern recognition, namely its range of validity and its limitation, is discussed in this paper conjointly with the function approximation theory of neural networks. The conclusion is that only if the sets to be recognized are linearly separable (which is rare) or the subsets, in which a segmental sample of the targets is involved,are linearly separable, can the classical 4f optical correlation system carry out the task of recognition inerrably. The recognition principle of a joint transform correlator is the same as that of a 4f system, and so is its range of validities. Based on the demonstration of the existence problem of optical correlation based pattern recognition an evaluation on some important problems that were studied in this field over the past 40 years is presented explicitly.

  3. Cartridge case image matching using effective correlation area based method.

    Science.gov (United States)

    Yammen, S; Muneesawang, P

    2013-06-10

    A firearm leaves a unique impression on fired cartridge cases. The cross-correlation function plays an important role in matching the characteristic features on the cartridge case found at the crime scene with a specific firearm, for accurate firearm identification. This paper proposes that the computational forensic techniques of alignment and effective correlation area-based approaches to image matching are essential to firearm identification. Specifically, the reference and the corresponding cartridge cases are aligned according to the phase-correlation criterion on the transform domain. The informative segments of the breech face marks are identified by a cross-covariance coefficient using the coefficient value in a window located locally in the image space. The segments are then passed to the measurement of edge density for computing effective correlation areas. Experimental results on a new dataset show that the correlation system can make use of the best properties of alignment and effective correlation area-based approaches, and can attain significant improvement of image-correlation results, compared with the traditional image-matching methods for firearm identification, which employ cartridge-case samples. An analysis of image-alignment score matrices suggests that all translation and scaling parameters are estimated correctly, and contribute to the successful extraction of effective correlation areas. It was found that the proposed method has a high discriminant power, compared with the conventional correlator. This paper advocates that this method will enable forensic science to compile a large-scale image database to perform correlation of cartridge case bases, in order to identify firearms that involve pairwise alignments and comparisons.

  4. LOW CONCENTRATION MERCURY SORPTION MECHANISMS AND CONTROL BY CALCIUM-BASED SORBENTS; APPLICATION IN COAL-FIRED PROCESSES

    Science.gov (United States)

    The capture of elemental mercury (Hgo) and mercuric chloride (HgCl2) by three types of calcium (Ca)-based sorbents was examined in this bench-scale study under conditions prevalent in coal fired utilities. Ca-based sorbent performances were compared to that of an activated carbon...

  5. Calcium - urine

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003603.htm Calcium - urine To use the sharing features on this ... enable JavaScript. This test measures the amount of calcium in urine. All cells need calcium in order ...

  6. Calcium supplements

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/007477.htm Calcium supplements To use the sharing features on this page, please enable JavaScript. WHO SHOULD TAKE CALCIUM SUPPLEMENTS? Calcium is an important mineral for the ...

  7. Bond strength of a calcium silicate-based sealer tested in bulk or with different main core materials

    OpenAIRE

    Nagas, Emre; Cehreli, Zafer; Mehmet Ozgur UYANIK; Veli DURMAZ

    2014-01-01

    The aim of this study was to evaluate the influence of a calcium silicate-based sealer (iRoot SP), with or without a core material, on bond strength to radicular dentin, in comparison with various contemporary root filling systems. Root canals of freshly extracted single-rooted teeth (n = 60) were instrumented using rotary instruments. The roots were randomly assigned to one of the following experimental groups: (1) a calcium silicate-based sealer without a core material (bulk-fill); (2) a ca...

  8. Markov chaotic sequences for correlation based watermarking schemes

    Energy Technology Data Exchange (ETDEWEB)

    Tefas, A.; Nikolaidis, A.; Nikolaidis, N.; Solachidis, V.; Tsekeridou, S.; Pitas, I. E-mail: pitas@zeus.csd.auth.gr

    2003-07-01

    In this paper, statistical analysis of watermarking schemes based on correlation detection is presented. Statistical properties of watermark sequences generated by piecewise-linear Markov maps are exploited, resulting in superior watermark detection reliability. Correlation/spectral properties of such sequences are easily controllable, a fact that affects the watermarking system performance. A family of chaotic maps, namely the skew tent map family, is proposed for use in watermarking schemes.

  9. Color-image retrieval based on fuzzy correlation

    Institute of Scientific and Technical Information of China (English)

    ZHAI Hongchen; LIANG Yanmei; MU Guoguang

    2004-01-01

    We report a method of color-image retrieval based on fuzzy correlation, in which α-cut relations in fuzzy set theory are applied to defining color match and height match of color peaks for synthesizing fuzzy correlation of two color histograms, and RGB space is partitioned into six sub-regions in the experiment for the regional color comparisons. Experimental results show that the efficiency of the color-image retrieval can be effectively improved by this approach.

  10. A chemical activity evaluation of two dental calcium silicate-based materials

    Directory of Open Access Journals (Sweden)

    Chalas Renata

    2015-06-01

    Full Text Available Calcium silicate-based materials are interesting products widely used in dentistry. The study was designed to compare the chemical reaction between analyzed two preparates and dentin during cavity lining. In our work, dentinal discs were prepared from human extracted teeth filled with Biodentine and MTA+. The samples were then analyzed by way of SEM, EDS and Raman spectroscopy. The obtained results revealed differences in elemental composition between both materials. Biodentine showed higher activity in contact with dentine. Moreover, the interfacial layer in the tooth filled by Biodentine was wider than that in the tooth filled with MTA+. The applied methods of analysis confirmed that both materials have a bioactive potential which is a promising ability.

  11. Light Hydrocarbons Adsorption Mechanisms in Two Calcium-based Microporous Metal Organic Frameworks

    KAUST Repository

    Plonka, Anna M.

    2016-01-25

    The adsorption mechanism of ethane, ethylene and acetylene (C2Hn; n=2, 4, 6) on two microporous metal organic frameworks (MOFs) is described here that is consistent with observations from single crystal and powder X-ray diffraction, calorimetric measurments and gas adsorption isotherm measurements. Two calcium-based MOFs, designated as SBMOF-1 and SBMOF-2 (SB: Stony Brook), form three-dimensional frameworks with one-dimensional open channels. As determined form single crystal diffraction experiments channel geometries of both SBMOF-1 and SBMOF-2 provide multiple adsorption sites for hydrocarbon molecules trough C-H…π and C-H…O interactions, similarly to interactions in the molecular and protein crystals. Both materials selectively adsorb C2 hydrocarbon gases over methane as determined with IAST and breakthrough calculations, with C2H6/CH4 selectivity as high as 74 in SBMOF-1.

  12. A new evaporation-based method for the preparation of biomimetic calcium phosphate coatings on metals

    International Nuclear Information System (INIS)

    This study reports a new method to prepare biomimetic calcium phosphate coatings on titanium, stainless steel, CoCrMo, and tantalum. The method does not require surface etching, high supersaturation, or tight control of solution conditions. Metallic samples were dipped into a supersaturated calcium phosphate solution, withdrawn, and left to dry at room temperature. Calcium phosphate crystallites formed on and completely covered the surfaces by repeating the dip-and-dry treatment. The crystallite-covered surfaces readily grew to calcium phosphate coatings when immersed in the supersaturated solution. The mechanism of the treatment was suggested to be an evaporation-induced surface crystallization process.

  13. Structure-Composition-Property Relationships in Polymeric Amorphous Calcium Phosphate-Based Dental Composites

    Directory of Open Access Journals (Sweden)

    Drago Skrtic

    2009-11-01

    Full Text Available Our studies of amorphous calcium phosphate (ACP-based materials over the last decade have yielded bioactive polymeric composites capable of protecting teeth from demineralization or even regenerating lost tooth mineral. The anti-cariogenic/remineralizing potential of these ACP composites originates from their propensity, when exposed to the oral environment, to release in a sustained manner sufficient levels of mineral-forming calcium and phosphate ions to promote formation of stable apatitic tooth mineral. However, the less than optimal ACP filler/resin matrix cohesion, excessive polymerization shrinkage and water sorption of these experimental materials can adversely affect their physicochemical and mechanical properties, and, ultimately, limit their lifespan. This study demonstrates the effects of chemical structure and composition of the methacrylate monomers used to form the matrix phase of composites on degree of vinyl conversion (DVC and water sorption of both copolymers and composites and the release of mineral ions from the composites. Modification of ACP surface via introducing cations and/or polymers ab initio during filler synthesis failed to yield mechanically improved composites. However, moderate improvement in composite’s mechanical stability without compromising its remineralization potential was achieved by silanization and/or milling of ACP filler. Using ethoxylated bisphenol A dimethacrylate or urethane dimethacrylate as base monomers and adding moderate amounts of hydrophilic 2-hydroxyethyl methacrylate or its isomer ethyl-α-hydroxymethacrylate appears to be a promising route to maximize the remineralizing ability of the filler while maintaining high DVC. Exploration of the structure/composition/property relationships of ACP fillers and polymer matrices is complex but essential for achieving a better understanding of the fundamental mechanisms that govern dissolution/re-precipitation of bioactive ACP fillers, and

  14. Application of the specular and diffuse reflection analysis for in vitro diagnostics of dental erosion: correlation with enamel softening, roughness, and calcium release

    Science.gov (United States)

    Rakhmatullina, Ekaterina; Bossen, Anke; Höschele, Christoph; Wang, Xiaojie; Beyeler, Barbara; Meier, Christoph; Lussi, Adrian

    2011-10-01

    We present assembly and application of an optical reflectometer for the analysis of dental erosion. The erosive procedure involved acid-induced softening and initial substance loss phases, which are considered to be difficult for visual diagnosis in a clinic. Change of the specular reflection signal showed the highest sensitivity for the detection of the early softening phase of erosion among tested methods. The exponential decrease of the specular reflection intensity with erosive duration was compared to the increase of enamel roughness. Surface roughness was measured by optical analysis, and the observed tendency was correlated with scanning electron microscopy images of eroded enamel. A high correlation between specular reflection intensity and measurement of enamel softening (r2 >= -0.86) as well as calcium release (r2 >= -0.86) was found during erosion progression. Measurement of diffuse reflection revealed higher tooth-to-tooth deviation in contrast to the analysis of specular reflection intensity and lower correlation with other applied methods (r2 = 0.42-0.48). The proposed optical method allows simple and fast surface analysis and could be used for further optimization and construction of the first noncontact and cost-effective diagnostic tool for early erosion assessment in vivo.

  15. Evaluation of automated attenuation-based tube current adaptation for coronary calcium scoring in MDCT in a cohort of 262 patients

    International Nuclear Information System (INIS)

    The aim of our study was to evaluate attenuation-based tube current adaptation in coronary calcium scoring using ECG-gated multi-detector-row CT (MDCT). A total of 262 patients underwent non-enhanced cardiac MDCT. Group 1 was scanned using a standard protocol with 120 kV and 150 mAseff. Groups 2-4 were scanned using an attenuation-based dose-adaptation template (CARE Dose) with different effective reference mAs settings (150, 180, 210 mAseff). Body-mass index (BMI) and CT-dose index values were calculated for each patient. Image noise and subjective image quality were assessed. Regression analysis was performed, and the variation coefficient of image noise was determined. Compared to the standard scan protocol a dose reduction of 31.1% for group 2 and 20.1% for group 3 was observed. Measurement variation of image noise was smaller for the attenuation-based dose adaptation protocols (group 2-4) (16.2-17.1%) compared to the standard scan protocol (32.3%). Regression analysis of groups 2-4 showed better correlation with improved dose usage based on BMI (all P ≤ 0.001). Median image quality was ''excellent'' in groups 2-4 and ''good'' in group 1. Automated attenuation-based tube current adaptation in coronary calcium scoring is technically feasible, can decrease patient dose, and reduces variation in image noise as a sign of improved dose usage. (orig.)

  16. Effective information spreading based on local information in correlated networks

    CERN Document Server

    Gao, Lei; Pan, Liming; Tang, Ming; Zhang, Hai-Feng

    2016-01-01

    Using network-based information to facilitate information spreading is an essential task for spreading dynamics in complex networks, which will benefit the promotion of technical innovations, healthy behaviors, new products, etc. Focusing on degree correlated networks, we propose a preferential contact strategy based on the local network structure and local informed density to promote the information spreading. During the spreading process, an informed node will preferentially select a contact target among its neighbors, basing on their degrees or local informed densities. By extensively implementing numerical simulations in synthetic and empirical networks, we find that when only consider the local structure information, the convergence time of information spreading will be remarkably reduced if low-degree neighbors are favored as contact targets. Meanwhile, the minimum convergence time depends non-monotonically on degree-degree correlation, and moderate correlation coefficients result in most efficient info...

  17. Correlation theory-based signal processing method for CMF signals

    Science.gov (United States)

    Shen, Yan-lin; Tu, Ya-qing

    2016-06-01

    Signal processing precision of Coriolis mass flowmeter (CMF) signals affects measurement accuracy of Coriolis mass flowmeters directly. To improve the measurement accuracy of CMFs, a correlation theory-based signal processing method for CMF signals is proposed, which is comprised of the correlation theory-based frequency estimation method and phase difference estimation method. Theoretical analysis shows that the proposed method eliminates the effect of non-integral period sampling signals on frequency and phase difference estimation. The results of simulations and field experiments demonstrate that the proposed method improves the anti-interference performance of frequency and phase difference estimation and has better estimation performance than the adaptive notch filter, discrete Fourier transform and autocorrelation methods in terms of frequency estimation and the data extension-based correlation, Hilbert transform, quadrature delay estimator and discrete Fourier transform methods in terms of phase difference estimation, which contributes to improving the measurement accuracy of Coriolis mass flowmeters.

  18. The prevalence of chondrocalcinosis of the symphysis pubis on CT scan and correlation with calcium pyrophosphate dihydrate crystal deposition disease.

    Science.gov (United States)

    Patel, Trusha; Ryan, Lawrence; Dubois, Melissa; Carrera, Guillermo; Baynes, Keith; Mannem, Rajeev; Mulkerin, Jennifer; Visotcky, Alexis

    2016-03-01

    Calcium pyrophosphate dihydrate (CPP) crystal deposition in the articular cartilage can often be seen radiographically as chondrocalcinosis (CC). CPP crystals preferentially deposit in fibrocartilages such as the knee menisci and symphysis pubis (SP). We sought to determine the prevalence of CC in the SP on computed tomography (CT) of the abdomen and pelvis. This retrospective study involved readings on 1070 consecutive CTs of the abdomen and pelvis performed over 3 months in patients over 65 years of age. Medical records of 226 patients found to have CC were reviewed to determine age, gender, documentation of CPPD on problem lists or in medical histories, and whether radiology readings of the CTs mentioned CC. SP CC was identified in 21.1 % (226/1070) of consecutive CT scans with the mean age of CT+ patients being 78.6. Of the 226 patients with SP CC, the observation of CC was documented in only 5.3 % (12/226) of the radiology reports. Of the 12 instances in which the radiology reports mentioned CC, this observation was never (0/12) transmitted to the medical history or problem list. The prevalence of SP CC in patients older than 65 was 21.1 %. Since the majority of CTs of the abdomen and pelvis are not ordered for evaluation of musculoskeletal conditions, this is likely a true prevalence without selection bias. When CC of the SP was present on images, radiologists routinely overlooked or chose not to report CC. Even in the rare instances when it was reported, that information was not added to the medical history or problem list. There are several clinical situations (e.g., acute monoarthritis or atypical osteoarthritis) in which recognizing that a patient has CPP deposition would be useful. Taking the time to review images may yield clinically important findings that are not mentioned anywhere on the patient chart.

  19. Characterization of a calcium phosphate cement based on alpha-tricalcium phosphate obtained by wet precipitation process

    International Nuclear Information System (INIS)

    There are several systems of calcium phosphate cements being studied. Those based on alpha-tricalcium phosphate are of particular interest. After setting they produce calcium deficient hydroxyapatite similar to bone like hydroxyapatite. This work aims to obtain alpha-tricalcium phosphate powders by the wet precipitation process, using calcium nitrate and phosphoric acid as reagents. This powder was characterized by infrared spectroscopy, X-ray diffraction and particle size distribution. In order to prepare the calcium phosphate cement, the powder was mixed with an accelerator in an aqueous solution. The mechanical properties of the cement were assessed and it was evaluated by means of apparent density, X-ray diffraction and scanning electron microscopy. The described method produced crystalline alpha-tricalcium phosphate as the major phase. The calcium phosphate cement showed high values of compression strength (50 MPa). The soaking of the cement in a simulated body fluid (SBF) formed a layer of hydroxyapatite like crystals in the surface of the samples. (author)

  20. Association of calcemia and serum vitamin D with 24H-urinary calcium excretion in a swiss population-based study

    OpenAIRE

    Rathod A.; Bonny O.; Guessous I.; Suter P.M.; Conen D; Erne P.; Péchère-Bertschi A.; Paccaud F.; Burnier M; Bochud M

    2013-01-01

    Background: Elevated urinary calcium excretion is associated with reduced bone mineral density. Population-based data on urinary calcium excretion are scarce. We explored the association of serum calcium and circulating levels of vitamin D (including 25(OH)D2 and 25(OH)D3) with urinary calcium excretion in men and women in a population-based study. Methods: We used data from the "Swiss Survey on Salt" conducted between 2010 and 2012 and including people aged 15 years and over. Twenty-four hou...

  1. Repeat Sequences and Base Correlations in Human Y Chromosome Palindromes

    Institute of Scientific and Technical Information of China (English)

    Neng-zhi Jin; Zi-xian Liu; Yan-jiao Qi; Wen-yuan Qiu

    2009-01-01

    On the basis of information theory and statistical methods, we use mutual information, n-tuple entropy and conditional entropy, combined with biological characteristics, to analyze the long range correlation and short range correlation in human Y chromosome palindromes. The magnitude distribution of the long range correlation which can be reflected by the mutual information is P5>P5a>P5b (P5a and P5b are the sequences that replace solely Alu repeats and all interspersed repeats with random uncorrelated sequences in human Y chromosome palindrome 5, respectively); and the magnitude distribution of the short range correlation which can be reflected by the n-tuple entropy and the conditional entropy is P5>P5a>P5b>random uncorrelated sequence. In other words, when the Alu repeats and all interspersed repeats replace with random uncorrelated sequence, the long range and short range correlation decrease gradually. However, the random uncorrelated sequence has no correlation. This research indicates that more repeat sequences result in stronger correlation between bases in human Y chromosome. The analyses may be helpful to understand the special structures of human Y chromosome palindromes profoundly.

  2. Comparative evaluation of genetic diversity using RAPD, SSR and cytochrome P450 gene based markers with respect to calcium content in finger millet (Eleusine coracana L. Gaertn.)

    Indian Academy of Sciences (India)

    Preety Panwar; Manoj Nath; Vijay Kumar Yadav; Anil Kumar

    2010-08-01

    Genetic relationships among 52 Eleusine coracana (finger millet) genotypes collected from different districts of Uttarakhand were investigated by using randomly amplified polymorphic DNA (RAPD), simple sequence repeat (SSR) and cytochrome P450 gene based markers. A total of 18 RAPD primers, 10 SSR primers, and 10 pairs of cytochrome P450 gene based markers, respectively, revealed 49.4%, 50.2% and 58.7% polymorphism in 52 genotypes of E. coracana. Mean polymorphic information content (PIC) for each of these marker systems (0.351 for RAPD, 0.505 for SSR and 0.406 for cyt P450 gene based markers) suggested that all the marker systems were effective in determining polymorphisms. Pair-wise similarity index values ranged from 0.011 to 0.999 (RAPD), 0.010 to 0.999 (SSR) and 0.001 to 0.998 (cyt P450 gene based markers) and mean similarity index value of 0.505, 0.504 and 0.499, respectively. The dendrogram developed by RAPD, SSR and cytochrome P450 gene based primers analyses revealed that the genotypes are grouped in different clusters according to high calcium (300–450 mg/100 g), medium calcium (200–300 mg/100 g) and low calcium (100–200 mg/100 g). Mantel test employed for detection of goodness of fit established cophenetic correlation values above 0.95 for all the three marker systems. The dendrograms and principal coordinate analysis (PCA) plots derived from the binary data matrices of the three marker systems are highly concordant. High bootstrap values were obtained at major nodes of phenograms through WINBOOT software. Comparison of RAPD, SSR and cytochrome P450 gene based markers, in terms of the quality of data output, indicated that SSRs and cyt P450 gene based markers are particularly promising for the analysis of plant genome diversity. The genotypes of finger millet collected from different districts of Uttarakhand constitute a wide genetic base and clustered according to calcium contents. The identified genotypes could be used in breeding programmes and

  3. Radiotracer studies on calcium ion-selective electrode membranes based on poly(vinyl chloride) matrices.

    Science.gov (United States)

    Craggs, A; Moody, G J; Thomas, J D; Willcox, A

    Radiotracer studies with (45)Ca and (36)Cl demonstrate that PVC matrix membranes containing Orion 92-20-02 liquid calcium ion-exchanger are permselective to counter-cations. Diffusion coefficients are quoted for the migration of (45)Ca between pairs of calcium solutions and are discussed in terms of solution concentration, membrane thickness and concentration level of sensor in the membrane. Migration of calcium ions from calcium chloride solution to a Group (II) metal chloride solution through a PVC membrane containing calcium liquid ion-exchanger is discussed in terms of solvent extraction and electrode selectivity coefficient parameters. Thus, magnesium, strontium and barium ions appear to inhibit migration through the membrane by their low affinity for the membrane liquid ion-exchanger sites, while the inhibition by beryllium ions is attributed to site blockage by the strong affinity of dialkylphosphate sites for beryllium.

  4. Mechanochemically Activated, Calcium Oxide-Based, Magnesium Oxide-Stabilized Carbon Dioxide Sorbents.

    Science.gov (United States)

    Kurlov, Alexey; Broda, Marcin; Hosseini, Davood; Mitchell, Sharon J; Pérez-Ramírez, Javier; Müller, Christoph R

    2016-09-01

    Carbon dioxide capture and storage (CCS) is a promising approach to reduce anthropogenic CO2 emissions and mitigate climate change. However, the costs associated with the capture of CO2 using the currently available technology, that is, amine scrubbing, are considered prohibitive. In this context, the so-called calcium looping process, which relies on the reversible carbonation of CaO, is an attractive alternative. The main disadvantage of naturally occurring CaO-based CO2 sorbents, such as limestone, is their rapid deactivation caused by thermal sintering. Here, we report a scalable route based on wet mechanochemical activation to prepare MgO-stabilized, CaO-based CO2 sorbents. We optimized the synthesis conditions through a fundamental understanding of the underlying stabilization mechanism, and the quantity of MgO required to stabilize CaO could be reduced to as little as 15 wt %. This allowed the preparation of CO2 sorbents that exceed the CO2 uptake of the reference limestone by 200 %.

  5. Mechanochemically Activated, Calcium Oxide-Based, Magnesium Oxide-Stabilized Carbon Dioxide Sorbents.

    Science.gov (United States)

    Kurlov, Alexey; Broda, Marcin; Hosseini, Davood; Mitchell, Sharon J; Pérez-Ramírez, Javier; Müller, Christoph R

    2016-09-01

    Carbon dioxide capture and storage (CCS) is a promising approach to reduce anthropogenic CO2 emissions and mitigate climate change. However, the costs associated with the capture of CO2 using the currently available technology, that is, amine scrubbing, are considered prohibitive. In this context, the so-called calcium looping process, which relies on the reversible carbonation of CaO, is an attractive alternative. The main disadvantage of naturally occurring CaO-based CO2 sorbents, such as limestone, is their rapid deactivation caused by thermal sintering. Here, we report a scalable route based on wet mechanochemical activation to prepare MgO-stabilized, CaO-based CO2 sorbents. We optimized the synthesis conditions through a fundamental understanding of the underlying stabilization mechanism, and the quantity of MgO required to stabilize CaO could be reduced to as little as 15 wt %. This allowed the preparation of CO2 sorbents that exceed the CO2 uptake of the reference limestone by 200 %. PMID:27529608

  6. Copula-based dynamic conditional correlation multiplicative error processes

    OpenAIRE

    Bodnar, Taras; Hautsch, Nikolaus

    2013-01-01

    We introduce a copula-based dynamic model for multivariate processes of (non-negative) high-frequency trading variables revealing time-varying conditional variances and correlations. Modeling the variables’ conditional mean processes using a multiplicative error model we map the resulting residuals into a Gaussian domain using a Gaussian copula. Based on high-frequency volatility, cumulative trading volumes, trade counts and market depth of various stocks traded at the NYSE, we show that the ...

  7. Low spatial correlation at base station uniform linear antennas

    Institute of Scientific and Technical Information of China (English)

    Xiao Hailin; Nie Zaiping

    2006-01-01

    A spatial channel propagation model is presented. Consider a uniform linear antenna (ULA) at the base station (BS) and narrowband signals transmitted at the mobile. In two types of propagating environments: indoor and outdoor, performance of low spatial correlation is investigated and some results are provided, which are significant to analyze the performance of diversity systems and configuration of array. The results also show that the configuration of array with either smaller angular spread or bigger angle of arrival (AOA) dominates the impact on spatial correlation, and that increasing angular spread or decreasing AOA diminishes, or even eliminates this impact.

  8. Influences of iron and calcium carbonate on wastewater treatment performances of algae based reactors.

    Science.gov (United States)

    Zhao, Zhimiao; Song, Xinshan; Wang, Wei; Xiao, Yanping; Gong, Zhijie; Wang, Yuhui; Zhao, Yufeng; Chen, Yu; Mei, Mengyuan

    2016-09-01

    The influences of iron and calcium carbonate (CaCO3) addition in wastewater treatments reactors performance were investigated. Adding different concentrations of Fe(3+) (5, 10, 30 and 50mmol/m(3)), iron and CaCO3 powder led to changes in algal characteristics and physico-chemical and microbiological properties. According to the investigation results, nutrient removal efficiency in algae based reactors was obviously increased by the addition of 10mmol/m(3) Fe(3+), iron (5mmol/m(3)) and CaCO3 powder (0.2gm(-3)) and the removal efficiencies of BOD5, TN, and TP in Stage 2 were respectively increased by 28%, 8.9%, and 22%. The improvements in physico-chemical performances were verified by microbial community tests (bacteria quantity, activity and community measured in most probable number, extracellular enzymes activity, and Biolog Eco Plates). Microbial variations indicated the coexistence of Fe ions and carbonate-bicarbonate, which triggered the synergistic effect of physico-chemical action and microbial factors in algae based reactors. PMID:27214163

  9. Correlates of gender and achievement in introductory algebra based physics

    Science.gov (United States)

    Smith, Rachel Clara

    The field of physics is heavily male dominated in America. Thus, half of the population of our country is underrepresented and underserved. The identification of factors that contribute to gender disparity in physics is necessary for educators to address the individual needs of students, and, in particular, the separate and specific needs of female students. In an effort to determine if any correlations could be established or strengthened between sex, gender identity, social network, algebra skill, scientific reasoning ability, and/or student attitude, a study was performed on a group of 82 students in an introductory algebra based physics course. The subjects each filled out a survey at the beginning of the semester of their first semester of algebra based physics. They filled out another survey at the end of that same semester. These surveys included physics content pretests and posttests, as well as questions about the students' habits, attitudes, and social networks. Correlates of posttest score were identified, in order of significance, as pretest score, emphasis on conceptual learning, preference for male friends, number of siblings (negatively correlated), motivation in physics, algebra score, and parents' combined education level. Number of siblings was also found to negatively correlate with, in order of significance, gender identity, preference for male friends, emphasis on conceptual learning, and motivation in physics. Preference for male friends was found to correlate with, in order of significance, emphasis on conceptual learning, gender identity, and algebra score. Also, gender identity was found to correlate with emphasis on conceptual learning, the strongest predictor of posttest score other than pretest score.

  10. Biocompatibility of a new nanomaterial based on calcium silicate implanted in subcutaneous connective tissue of rats

    OpenAIRE

    Petrović Violeta; Opačić-Galić Vanja; Jokanović V.; Jovanović M.; Basta-Jovanović Gordana; Živković S.

    2012-01-01

    The aim of the study was to investigate rat connective tissue response to a new calcium silicate system 7, 15, 30 and 60 days after implantation. Twenty Wistar albino male rats received two tubes half-filled with a new calcium silicate system (NCSS) or MTA in subcutaneous tissue. The empty half of the tubes served as controls. Five animals were sacrificed after 7, 15, 30 and 60 days and samples of the subcutaneous tissue around implanted material were submi...

  11. Spectral methods and cluster structure in correlation-based networks

    Science.gov (United States)

    Heimo, Tapio; Tibély, Gergely; Saramäki, Jari; Kaski, Kimmo; Kertész, János

    2008-10-01

    We investigate how in complex systems the eigenpairs of the matrices derived from the correlations of multichannel observations reflect the cluster structure of the underlying networks. For this we use daily return data from the NYSE and focus specifically on the spectral properties of weight W=|-δ and diffusion matrices D=W/sj-δ, where C is the correlation matrix and si=∑jW the strength of node j. The eigenvalues (and corresponding eigenvectors) of the weight matrix are ranked in descending order. As in the earlier observations, the first eigenvector stands for a measure of the market correlations. Its components are, to first approximation, equal to the strengths of the nodes and there is a second order, roughly linear, correction. The high ranking eigenvectors, excluding the highest ranking one, are usually assigned to market sectors and industrial branches. Our study shows that both for weight and diffusion matrices the eigenpair analysis is not capable of easily deducing the cluster structure of the network without a priori knowledge. In addition we have studied the clustering of stocks using the asset graph approach with and without spectrum based noise filtering. It turns out that asset graphs are quite insensitive to noise and there is no sharp percolation transition as a function of the ratio of bonds included, thus no natural threshold value for that ratio seems to exist. We suggest that these observations can be of use for other correlation based networks as well.

  12. Injectable nanoamorphous calcium phosphate based in situ gel systems for the treatment of periapical lesions.

    Science.gov (United States)

    Mostafa, Amany A; Zaazou, Mohamed H; Chow, Laurence C; Mahmoud, Azza A; Zaki, Dalia Y; Basha, Mona; Abdel Hamid, Mohamed A; Khallaf, Maram E; Sharaf, Nehal F; Hamdy, Tamer M

    2015-12-01

    Nonsurgical local treatment of a periapical lesion arising from trauma or bacterial infection is a promising innovative approach. The present study investigated the feasibility of developing injectable amorphous calcium phosphate nanoparticles (ACP NPs) and ACP NPs loaded with an anti-inflammatory drug; ibuprofen (IBU-ACP NPs) in the form of thermoreversible in situ gels to treat periapical lesions with the stimulation of bone formation. NPs were produced by a spray-drying technique. Different formulations of Poloxamer 407 were incorporated with/without the produced NPs to form injectable gels. A drug release study was carried out. A 3 month in vivo test on a dog model also was assessed. Results showed successful incorporation of the drug into the NPs of CP during spray drying. The particles had mean diameters varying from 100 to 200 nm with a narrow distribution. A drug release study demonstrated controlled IBU release from IBU-ACP NPs at a pH of 7.4 over 24 h. The gelation temperature of the injectable in situ gels based on Poloxamer 407 was measured to be 30 °C. After 3 months of implantation in dogs, the results clearly demonstrated that the inclusion of ACP NPs loaded with IBU showed high degrees of periapical bone healing and cementum layer deposition around the apical root tip.

  13. Formation of sterilized edible-films based on caseinates: Effects of calcium and plasticizers

    International Nuclear Information System (INIS)

    Gamma-irradiation was used to produce free-standing sterilized edible films based on caseinate. The effect of calcium ions (Ca2+) and two plasticizers, namely propylene glycol (PG) and triethylene glycol (TEG) were investigated, as well as the effect of the irradiation on both the gel formation and mechanical properties of the resulting films. Gamma-irradiation provoked formation of bityrosine, i.e. crosslinks, accounting for the increase of the puncture strength of films. The presence of PG or TEG enhanced the formation of crosslinks, leading to an improved mechanical strength of films. TEG was found to interact more favorably with the caseinate than PG, being responsible for the improved film extensibility. Addition of CA2+ caused the formation of gels. The breaking strength of gels was directly related to the concentration of Ca2+, while the puncture strength of films was found to be almost independent. Moreover, high irradiation dose seemed to affect the protein structure, accounting for the decrease of the breaking strength of gels and for the depreciation of the mechanical behavior of films

  14. Biocalcite, a multifunctional inorganic polymer: Building block for calcareous sponge spicules and bioseed for the synthesis of calcium phosphate-based bone

    Directory of Open Access Journals (Sweden)

    Xiaohong Wang

    2014-05-01

    Full Text Available Calcium carbonate is the material that builds up the spicules of the calcareous sponges. Recent results revealed that the calcium carbonate/biocalcite-based spicular skeleton of these animals is formed through an enzymatic mechanism, such as the skeleton of the siliceous sponges, evolutionarily the oldest animals that consist of biosilica. The enzyme that mediates the calcium carbonate deposition has been identified as a carbonic anhydrase (CA and has been cloned from the calcareous sponge species Sycon raphanus. Calcium carbonate deposits are also found in vertebrate bones besides the main constituent, calcium phosphate/hydroxyapatite (HA. Evidence has been presented that during the initial phase of HA synthesis poorly crystalline carbonated apatite is deposited. Recent data summarized here indicate that during early bone formation calcium carbonate deposits enzymatically formed by CA, act as potential bioseeds for the precipitation of calcium phosphate mineral onto bone-forming osteoblasts. Two different calcium carbonate phases have been found during CA-driven enzymatic calcium carbonate deposition in in vitro assays: calcite crystals and round-shaped vaterite deposits. The CA provides a new target of potential anabolic agents for treatment of bone diseases; a first CA activator stimulating the CA-driven calcium carbonate deposition has been identified. In addition, the CA-driven calcium carbonate crystal formation can be frozen at the vaterite state in the presence of silintaphin-2, an aspartic acid/glutamic acid-rich sponge-specific protein. The discovery that calcium carbonate crystals act as bioseeds in human bone formation may allow the development of novel biomimetic scaffolds for bone tissue engineering. Na-alginate hydrogels, enriched with biosilica, have recently been demonstrated as a suitable matrix to embed bone forming cells for rapid prototyping bioprinting/3D cell printing applications.

  15. Calcium oxide as a solid base catalyst for transesterification of soybean oil and its application to biodiesel production

    Energy Technology Data Exchange (ETDEWEB)

    Masato Kouzu; Takekazu Kasuno; Masahiko Tajika; Yoshikazu Sugimoto; Shinya Yamanaka; Jusuke Hidaka [Keihanna Interaction Plaza Inc., Kyoto (Japan). JST-KFPT Core Research Center

    2008-09-15

    In order to study solid base catalyst for biodiesel production with environmental benignity, transesterification of edible soybean oil with refluxing methanol was carried out in the presence of calcium oxide (CaO), -hydroxide (Ca(OH){sub 2}), or -carbonate (CaCO{sub 3}). At 1 h of reaction time, yield of FAME was 93% for CaO, 12% for Ca(OH){sub 2}, and 0% for CaCO{sub 3}. Under the same reacting condition, sodium hydroxide with the homogeneous catalysis brought about the complete conversion into FAME. Also, CaO was used for the further tests transesterifying waste cooking oil (WCO) with acid value of 5.1 mg-KOH/g. The yield of FAME was above 99% at 2 h of reaction time, but a portion of catalyst changed into calcium soap by reacting with free fatty acids included in WCO at initial stage of the transesterification. Owing to the neutralizing reaction of the catalyst, concentration of calcium in FAME increased from 187 ppm to 3065 ppm. By processing WCO at reflux of methanol in the presence of cation-exchange resin, only the free fatty acids could be converted into FAME. The transesterification of the processed WCO with acid value of 0.3 mg-KOH/g resulted in the production of FAME including calcium of 565 ppm. 22 refs., 6 figs., 5 tabs.

  16. Early-age hydration and volume change of calcium sulfoaluminate cement-based binders

    Science.gov (United States)

    Chaunsali, Piyush

    Shrinkage cracking is a predominant deterioration mechanism in structures with high surface-to-volume ratio. One way to allay shrinkage-induced stresses is to use calcium sulfoaluminate (CSA) cement whose early-age expansion in restrained condition induces compressive stress that can be utilized to counter the tensile stresses due to shrinkage. In addition to enhancing the resistance against shrinkage cracking, CSA cement also has lower carbon footprint than that of Portland cement. This dissertation aims at improving the understanding of early-age volume change of CSA cement-based binders. For the first time, interaction between mineral admixtures (Class F fly ash, Class C fly ash, and silica fume) and OPC-CSA binder was studied. Various physico-chemical factors such as the hydration of ye'elimite (main component in CSA cement), amount of ettringite (the main phase responsible for expansion in CSA cement), supersaturation with respect to ettringite in cement pore solution, total pore volume, and material stiffness were monitored to examine early-age expansion characteristics. This research validated the crystallization stress theory by showing the presence of higher supersaturation level of ettringite, and therefore, higher crystallization stress in CSA cement-based binders. Supersaturation with respect to ettringite was found to increase with CSA dosage and external supply of gypsum. Mineral admixtures (MA) altered the expansion characteristics in OPC-CSA-MA binders with fixed CSA cement. This study reports that fly ash (FA) behaves differently depending on its phase composition. The Class C FA-based binder (OPC-CSA-CFA) ceased expanding beyond two days unlike other OPC-CSA-MA binders. Three factors were found to govern expansion of CSA cement-based binders: 1) volume fraction of ettringite in given pore volume, 2) saturation level of ettringite, and 3) dynamic modulus. Various models were utilized to estimate the macroscopic tensile stress in CSA cement-based

  17. Porogen-based solid freeform fabrication of polycaprolactone-calcium phosphate scaffolds for tissue engineering.

    Science.gov (United States)

    Mondrinos, Mark J; Dembzynski, Robert; Lu, Lin; Byrapogu, Venkata K C; Wootton, David M; Lelkes, Peter I; Zhou, Jack

    2006-09-01

    Drop on demand printing (DDP) is a solid freeform fabrication (SFF) technique capable of generating microscale physical features required for tissue engineering scaffolds. Here, we report results toward the development of a reproducible manufacturing process for tissue engineering scaffolds based on injectable porogens fabricated by DDP. Thermoplastic porogens were designed using Pro/Engineer and fabricated with a commercially available DDP machine. Scaffolds composed of either pure polycaprolactone (PCL) or homogeneous composites of PCL and calcium phosphate (CaP, 10% or 20% w/w) were subsequently fabricated by injection molding of molten polymer-ceramic composites, followed by porogen dissolution with ethanol. Scaffold pore sizes, as small as 200 microm, were attainable using the indirect (porogen-based) method. Scaffold structure and porosity were analyzed by scanning electron microscopy (SEM) and microcomputed tomography, respectively. We characterized the compressive strength of 90:10 and 80:20 PCL-CaP composite materials (19.5+/-1.4 and 24.8+/-1.3 Mpa, respectively) according to ASTM standards, as well as pure PCL scaffolds (2.77+/-0.26 MPa) fabricated using our process. Human embryonic palatal mesenchymal (HEPM) cells attached and proliferated on all scaffolds, as evidenced by fluorescent nuclear staining with Hoechst 33258 and the Alamar Blue assay, with increased proliferation observed on 80:20 PCL-CaP scaffolds. SEM revealed multilayer assembly of HEPM cells on 80:20 PCL-CaP composite, but not pure PCL, scaffolds. In summary, we have developed an SFF-based injection molding process for the fabrication of PCL and PCL-CaP scaffolds that display in vitro cytocompatibility and suitable mechanical properties for hard tissue repair. PMID:16678255

  18. HYPERTHERMIA, INTRACELLULAR FREE CALCIUM AND CALCIUM IONOPHORES

    NARCIS (Netherlands)

    STEGE, GJJ; WIERENGA, PK; KAMPINGA, HH; KONINGS, AWT

    1993-01-01

    It is shown that heat-induced increase of intracellular calcium does not correlate with hyperthermic cell killing. Six different cell lines were investigated; in four (EAT, HeLa S3, L5178Y-R and L5178Y-S) heat treatments killing 90% of the cells did not affect the levels of intracellular free calciu

  19. Inhibition of Calcium-Dependent Protein Kinase 1 (CDPK1) In Vitro by Pyrazolopyrimidine Derivatives Does Not Correlate with Sensitivity of Cryptosporidium parvum Growth in Cell Culture.

    Science.gov (United States)

    Kuhlenschmidt, Theresa B; Rutaganira, Florentine U; Long, Shaojun; Tang, Keliang; Shokat, Kevan M; Kuhlenschmidt, Mark S; Sibley, L David

    2016-01-01

    Cryptosporidiosis is a serious diarrheal disease in immunocompromised patients and malnourished children, and treatment is complicated by a lack of adequate drugs. Recent studies suggest that the natural occurrence of a small gatekeeper residue in serine threonine calcium-dependent protein kinase 1 (CDPK1) of Cryptosporidium parvum might be exploited to target this enzyme and block parasite growth. Here were explored the potency with which a series of pyrazolopyrimidine analogs, which are selective for small gatekeeper kinases, inhibit C. parvum CDPK1 and block C. parvum growth in tissue culture in vitro. Although these compounds potently inhibited kinase activity in vitro, most had no effect on parasite growth. Moreover, among those that were active against parasite growth, there was a very poor correlation with their 50% inhibitory concentrations against the enzyme. Active compounds also had no effect on cell invasion, unlike the situation in Toxoplasma gondii, where these compounds block CDPK1, prevent microneme secretion, and disrupt cell invasion. These findings suggest that CPDK1 is not essential for C. parvum host cell invasion or growth and therefore that it is not the optimal target for therapeutic intervention. Nonetheless, several inhibitors with low micromolar 50% effective concentrations were identified, and these may affect other essential targets in C. parvum that are worthy of further exploration. PMID:26552986

  20. Induction of DNA and RNA synthesis in murine B lymphocytes does not correlate with early changes in cytosolic free calcium concentration

    International Nuclear Information System (INIS)

    In order to ascertain if early changes in cytosolic free calcium concentration [Ca2+] are correlated with either activation, as defined by 3H-uridine incorporation or increase in cell size, or induction of DNA synthesis, 3H-thymidine incorporation, murine B lymphocytes were stimulated with preparations of lipopolysaccharide (LPS), rabbit anti-mouse Fab (RAMFab), and 12-O-tetradecanoyl-phorbol-13-acetate (TPA). LPS, although a potent inducer of 3H-thymidine incorporation does not cause an increase in [Ca2+]. F(ab')2RAMFab at 50 μs ml causes a 6X increase in 3H-thymidine incorporation as opposed to a 2-3X increase at 10 μg/ml. IgG-RAMFab at concentrations up to 50 μg/ml neither induces DNA synthesis nor activates cells by any criteria, including 3H-uridine incorporation, increase in cell size, and increase in I-A expression. Both RAMFab causes increases in [Ca2+] that saturate at 10 μg/ml. Minimally proliferative doses of TPA inhibit the increase in [Ca2+] caused by both preparations of RAMFab. However, B cells pretreated with TPA and then stimulated with 2 or 10 μg/ml of either preparation of RAMFab showed increases of 10 X in 3H-uridine and 100X in 3H-thymidine incorporation. These data demonstrate that there appears to be no correlation between early changes in [Ca2+] and either activation or induction of DNA synthesis in murine B cells

  1. [Calcium intake and glucose and lipids concetrations in overweight and obese patients].

    Science.gov (United States)

    Pachocka, Lucyna M; Nowak, Agnieszka; Targosz, Urszula; Kłosiewicz-Latoszek, Longina; Stolarska, Irena

    2007-01-01

    Well-balanced diet is one of the determinants of the health and wellbeing. Inadequate nutrients' intake can promote disease development. The purpose of this study was to assess the intake of calcium, phosphorus and protein and relation between calcium intake and lipids and glucose serum concentration in patients with obesity. The studied group consisted of 57 subjects, aged 21-63 years. Dietary assessment was based on 3-d dietary record. Serum lipids concentrations were assessed by enzymatic methods, serum calcium concentrations were assessed by Vitros 250. The mean calcium intake in men was 588.8 mg/d, in women 549.3 mg/d. Calcium intake was statistically significant correlated with glucose concentration in women and men, but not with lipids concentrations. Dietary calcium intake in studied group was below the RDA. Calcium intake could be one of determinants of glucose concentration in obese persons.

  2. Dissolution kinetics of polycrystalline calcium sulfate-based materials: influence of chemical modification.

    Science.gov (United States)

    Fisher, Robin D; Mbogoro, Michael M; Snowden, Michael E; Joseph, Maxim B; Covington, James A; Unwin, Patrick R; Walton, Richard I

    2011-09-01

    Using a channel flow cell (CFC) system, the dissolution kinetics of polycrystalline gypsum-based materials have been examined with the aim of understanding their interaction with water, a property that limits the applications of the material in many situations. ICP (inductively coupled plasma) analysis of elemental concentrations in solution as a function of time yields surface fluxes by using a finite element modeling approach to simulate the hydrodynamic behavior within the CFC. After correction for surface roughness, a value for the intrinsic dissolution flux into water of pure polycrystalline gypsum, CaSO(4).2H(2)O, of 1.1 (±0.4) × 10(-8) mol cm(-2) s(-1) has been obtained. The addition of known humid creep inhibitors to the gypsum samples, including boric acid, tartaric acid and 3,4,5-trihydroxybenzoic acid (gallic acid), was found to have little measurable effect on the dissolution kinetics of gypsum: all yielded dissolution fluxes of 1.4 (±0.6) × 10(-8) mol cm(-2) s(-1). However, trisodium trimetaphosphate (STMP) was found to have a small detectable inhibitory effect relative to pure gypsum yielding a flux of 7.4 (±2.0) × 10(-9) mol cm(-2) s(-1). The data strongly suggest that models for humid creep inhibition that involve dissolution-crystallization of gypsum crystallites are less likely than those that involve a hindered ingress of water into the gypsum matrix. For comparison, composite materials that comprised of calcium sulfate anhydrite (CaSO(4)) crystallites bound by a polyphosphate matrix were also studied. For some of these samples, Ca(2+) surface fluxes were observed to be ∼1 order of magnitude lower than values for polycrystalline gypsum control substrates, suggesting a useful way to impart water resistance to gypsum-based materials. PMID:21861513

  3. Early age corrosion of aluminium in calcium sulfo-aluminate cement based composites

    International Nuclear Information System (INIS)

    At present, encapsulation of low level and intermediate level nuclear wastes using Portland Cement (PC) based matrices is a preferred approach. However, it is now widely accepted that the high pH of the pore solution of these PC-based matrices (usually above pH 12.5) can cause concerns over the stability of certain wastes containing reactive metals, such as aluminium and uranium. One potential low pH system for reducing the corrosion of aluminium is calcium sulfo-aluminate cement (CSA). However, significant heat could be generated from the hydration of CSA, causing another concern to the nuclear industry. In the current study, various additives, namely pulverized fuel ash (PFA), ground granulated blast furnace slag (GGBS) and limestone powder (LSP) were used to replace part of the CSA in order to reduce the heat output. The results indicated that the replacement of CSA with GGBS, PFA and LSP can reduce the heat output of 100% CSA, although it is still higher than the control GGBS/PC 9:1 system. The corrosion rate of aluminium in each of the CSA composites was slightly higher than 100% CSA, however, all the CSA systems had corrosion rates lower than GGBS/PC 9:1 after 15 hours. Therefore, the composite CSA systems investigated in this study provide a good compromise between the heat output and the resistance to the corrosion of aluminium. Hence, offers a good potential for dealing with some historical nuclear wastes where the corrosion of aluminium is a concern. (authors)

  4. Correlation-based temperature and emissivity separation algorithm

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Based on analyzing the relationship between the atmospheric downward radiance and surface emis- sivity, this paper proposes a correlation criterion to optimize surface temperature during the process of temperature and emissivity separation from thermal infrared hyperspectral data, and puts forward the correlation-based temperature and emissivity separation algorithm (CBTES). The algorithm uses the correlation between the atmospheric downward radiance and surface emissivity to optimize surface temperature, and obtains surface emissivity with this temperature. The accuracy of CBTES was evalu- ated by the simulated thermal infrared hyperspectral data. The simulated results show that the CBTES can achieve high accuracy of temperature and emissivity inversion. CBTES has been compared with the iterative spectrally smooth temperature/emissivity separation (ISSTES), and the comparison results show that they have relative accuracy. Besides, CBTES is insensitive to the instrumental random noise and the change of atmospheric downward radiance during the measurements. As regards the noniso- thermal pixel, its radiometric temperature changes slowly with the wavenumber when its emissivity is defined as r-emissivity. The CBTES can be used to derive the equivalent temperature of nonisothermal pixel in a narrow spectral region when we assumed that the radiometric temperature is invariable in the narrow spectral region. The derived equivalent temperatures in multi-spectral regions in 714―1250 cm?1 can characterize the change trend of nonisothermal pixel’s radiometric temperature.

  5. Correlation-based temperature and emissivity separation algorithm

    Institute of Scientific and Technical Information of China (English)

    CHENG Jie; LIU QinHuo; LI XiaoWen; XIAO Qing; LIU Qiang; DU YongMing

    2008-01-01

    Based on analyzing the relationship between the atmospheric downward radiance and surface emissivity, this paper proposes a correlation criterion to optimize surface temperature during the process of temperature and emissivity separation from thermal infrared hyperspectral data, and puts forward the correlation-based temperature and emissivity separation algorithm (CBTES). The algorithm uses the correlation between the atmospheric downward radiance and surface emissivity to optimize surface temperature, and obtains surface emissivity with this temperature. The accuracy of CBTES was evaluated by the simulated thermal infrared hyperspectral data. The simulated results show that the CBTES can achieve high accuracy of temperature and emissivity inversion. CBTES has been compared with the iterative spectrally smooth temperature/emissivity separation (ISSTES), and the comparison results show that they have relative accuracy. Besides, CBTES is insensitive to the instrumental random noise and the change of atmospheric downward radiance during the measurements. As regards the nonisothermal pixel, its radiometric temperature changes slowly with the wavenumber when its emissivity is defined as r-emissivity. The CBTES can be used to derive the equivalent temperature of nonisothermal pixel in a narrow spectral region when we assumed that the radiometric temperature is invariable in the narrow spectral region. The derived equivalent temperatures in multi-spectral regions in 714-250cm-1 can characterize the change trend of nonisothermal pixel's radiometric temperature.

  6. Zinc absorption from composite meals. I. The significance of whest extraction rate, zinc, calcium, and protein content in meals based on bread.

    Science.gov (United States)

    Sandström, B; Arvidsson, B; Cederblad, A; Björn-Rasmussen, E

    1980-04-01

    The absorption of zinc in man from composite meals based on bread was measured with a radionuclide technique using 65Zn and whole-body counting. Bread was made up from wheat flour of 100 and 72% extraction rate. A lower absolute amount of zinc was absorbed from the white bread compared to the absorption from the same amount of wholemeal bread. When the two types of bread were enriched with zinc chloride the absorption was higher from the white bread than from the wholemeal bread. Addition of calcium in the form of milk products improved the absorption of zinc from a meal with wholemeal bread. A significant positive correlation was found between zinc absorption and the protein content in meals containing milk, cheese, beef, and egg in various combinations with the wholemeal bread.

  7. Robust Reservoir Generation by Correlation-Based Learning

    Directory of Open Access Journals (Sweden)

    Tadashi Yamazaki

    2009-01-01

    Full Text Available Reservoir computing (RC is a new framework for neural computation. A reservoir is usually a recurrent neural network with fixed random connections. In this article, we propose an RC model in which the connections in the reservoir are modifiable. Specifically, we consider correlation-based learning (CBL, which modifies the connection weight between a given pair of neurons according to the correlation in their activities. We demonstrate that CBL enables the reservoir to reproduce almost the same spatiotemporal activity patterns in response to an identical input stimulus in the presence of noise. This result suggests that CBL enhances the robustness in the generation of the spatiotemporal activity pattern against noise in input signals. We apply our RC model to trace eyeblink conditioning. The reservoir bridged the gap of an interstimulus interval between the conditioned and unconditioned stimuli, and a readout neuron was able to learn and express the timed conditioned response.

  8. Laser-diode-based joint transform correlator for fingerprint identification

    Science.gov (United States)

    Lal, Amit K.; Zang, De Yu; Millerd, James E.

    1999-01-01

    A laser-diode-based joint transform correlator (JTC) is reported here for the identification and discrimination of fingerprints. The system employs compact and inexpensive laser diodes as the light sources and a bacteriorhodopsin (BR) film in the Fourier plane, which can record the joint power spectrum without the need for expensive spatial light modulators or CCD cameras. The BR film also introduces nonlinearities in the Fourier plane which can improve JTC performance. In addition, real-time, all-optical programmable spatial filtering is demonstrated to improve the discrimination of the system. We present computer modeling and experimental results of this optical correlator, which shows excellent potential for the identification and discrimination of fingerprints.

  9. Effect of Calcium Leaching on the Properties of Cement-based Composites

    Institute of Scientific and Technical Information of China (English)

    LLIN Weiting; CHENG An; HUANG Ran; CHEN Chuntao; ZHOU Xingang

    2011-01-01

    Leaching is one of the major factors that alter the mechanical properties of cementbased composites.This study is aimed to investigate the effect of leaching on the properties of cementbased composites.Specimens with two water/cementitious ratios and two mineral admixtures were tested.An electrical potential was applied to accelerate the leaching process.Compressive strength test,scanning electronic microscopy,thermogravimetric analysis and X-ray diffraction analysis were conducted.Test results demonstrated that the calcium leaching reduced compressive strengths of concrete specimens,and such effect was prominent on the specimens without mineral admixtures.The leaching resistance increased with a decrease in water/cementitious ratio and an increase in amount of mineral admixtures.The mineral admixtures would reduce the amount of calcium hydroxide and refine the pore structure through pozzolanic reactions.A fair relationship was found between the calcium leaching and the compressive strength.

  10. Biocompatibility of artificial bone based on vancomycin loaded mesoporous silica nanoparticles and calcium sulfate composites.

    Science.gov (United States)

    Gu, Jisheng; Wang, Teng; Fan, Guoxin; Ma, Junhua; Hu, Wei; Cai, Xiaobing

    2016-04-01

    The aim of this study was to evaluate the in vitro and in vivo biocompatibility of artificial bone based on vancomycin loaded mesoporous silica nanoparticles and calcium sulfate composites. In vitro cytotoxicity tests by cholecystokinin octapeptide (CCK-8) assay showed that the 5%Van-MSN-CaSO4 and Van-CaSO4 bone cements were cytocompatible for mouse osteoblastic cell line MC3T3-E1. The microscopic observation confirmed that MC3T3-E1cells incubated with Van-CaSO4 group and 5%Van-MSN-CaSO4 group exhibited clear spindle-shaped changes, volume increase and maturation, showing that these cements supported adhesion of osteoblastic cells on their surfaces. In addition, the measurement of alkaline phosphatase activity revealed the osteoconductive property of these biomaterials. In order to assess in vivo biocompatibility, synthesized cements were implanted into the distal femur of twelve adult male and female New Zealand rabbits. After implantation in artificial defects of the distal femur, 5%Van-MSN-CaSO4 and Van-CaSO4 bone cements did not damage the function of main organs of rabbits. In addition, the Van-MSN-CaSO4 composite allowed complete repair of bone defects with new bone formation 3 months after implantation. These results show potential application of Van-MSN-CaSO4 composites as bone graft materials for the treatment of open fracture in human due to its mechanical, osteoconductive and potential sustained drug release characteristics and the absence of adverse effects on the body.

  11. Sulphation of calcium-based sorbents in circulating fluidised beds under oxy-fuel combustion conditions

    Energy Technology Data Exchange (ETDEWEB)

    Francisco Garcia-Labiano; Luis F. de Diego; Alberto Abad; Pilar Gayan; Margarita de las Obras-Loscertales; Aranzazu Rufas; Juan Adanez [Instituto de Carboquimica (CSIC), Zaragoza (Spain). Dept. Energy and Environment

    2009-07-01

    Sulphur Retention (SR) by calcium-based sorbents is a process highly dependent on the temperature and CO{sub 2} concentration. In circulating fluidised beds combustors (CFBC's) operating under oxy-fuel conditions, the sulphation process takes place in atmospheres enriched in CO{sub 2} with bed concentrations that can vary from 40 to 95%. Under so high CO{sub 2} concentrations, very different from that in conventional coal combustion atmosphere with air, the calcination and sulphation behaviour of the sorbent must be defined to optimise the SR process in the combustor. The objective of this work was to determine the SO{sub 2} retention capacity of a Spanish limestone at typical oxy-fuel conditions in CFBC's. Long term duration tests of sulphation (up to 24 h), to simulate the residence time of sorbents in CFBC's, were carried out by thermogravimetric analysis (TGA). Clear behaviour differences were found under calcining and non-calcining conditions. Especially relevant was the result obtained at calcining conditions but close to the thermodynamic temperature given for sorbent calcination. This situation must be avoided in CFBC's because the CO{sub 2} produced inside the particle during calcination can destroy the particles if a non-porous sulphate product layer has been formed around the particle. The effect of the main variables on the sorbent sulphation such as SO{sub 2} concentration, temperature, and particle size were analysed in the long term TGA tests. These data were also used to determine the kinetic parameters for the sulphation under oxy-fuel combustion conditions, which were able to adequately predict the sulphation conversion values in a wide range of operating conditions. 20 refs., 5 figs., 2 tabs.

  12. SE-SR with sorbents based on calcium aluminates: Process optimization

    International Nuclear Information System (INIS)

    Highlights: • State of the art and past experimental investigations were describe. • Feeding flow rate effect on SE-SR performance was investigated. • S/C and particle size effects on SE-SR performance were investigated. • CO2 capture capacity of M3 sorbent was compared to the state of the art. • Operating conditions of SE-SR process with M3 sorbent were optimized. - Abstract: The development of a sustainable power generation using fossil fuels will be strongly encouraged in the future in order to achieve European targets in terms of CO2 emissions. In this context, sorption-enhanced steam reforming (SE-SR) is a promising process that can be implemented as a CCS pre-combustion methodology. Regarding conventional catalyst-CO2 sorbent materials, main challenges concern the development of innovative CO2 sorbents with higher stability and regeneration temperature lower than CaO one. In recent study, a high-performance material based on incorporation of CaO particles into calcium aluminates was developed by authors exhibiting high sorption capacity and stability in multi cycle process. In this study, such a sorbent was packed, together with the catalyst, in a fixed bed reactor and tested in multi-cycle SE-SR process optimizing the operating conditions. Sensitivity analysis was carried out in reference to feeding flow rate, steam to carbon molar ratio and material particle size. The innovative sorbent exhibits, in optimized process, significant performance improvements (in terms of H2 purity and total CO2 amount adsorbed in each carbonation cycle) respect similar approaches available in the technical literature

  13. Evaluation of automated attenuation-based tube current adaptation for coronary calcium scoring in MDCT in a cohort of 262 patients

    Energy Technology Data Exchange (ETDEWEB)

    Muehlenbruch, Georg; Hohl, Christian; Das, Marco; Wildberger, Joachim E.; Thomas, Christoph; Guenther, Rolf W. [University Hospital (RWTH) Aachen, Department of Diagnostic Radiology, Aachen (Germany); Suess, Christoph; Klotz, Ernst; Flohr, Thomas [Siemens Medical Solutions, Computed Tomography, Forchheim (Germany); Koos, Ralf [University Hospital (RWTH) Aachen, Department of Cardiology, Aachen (Germany); Mahnken, Andreas H. [RWTH-Aachen University, Applied Medical Engineering, Helmholtz Institute, Aachen (Germany)

    2007-07-15

    The aim of our study was to evaluate attenuation-based tube current adaptation in coronary calcium scoring using ECG-gated multi-detector-row CT (MDCT). A total of 262 patients underwent non-enhanced cardiac MDCT. Group 1 was scanned using a standard protocol with 120 kV and 150 mAs{sub eff}. Groups 2-4 were scanned using an attenuation-based dose-adaptation template (CARE Dose) with different effective reference mAs settings (150, 180, 210 mAs{sub eff}). Body-mass index (BMI) and CT-dose index values were calculated for each patient. Image noise and subjective image quality were assessed. Regression analysis was performed, and the variation coefficient of image noise was determined. Compared to the standard scan protocol a dose reduction of 31.1% for group 2 and 20.1% for group 3 was observed. Measurement variation of image noise was smaller for the attenuation-based dose adaptation protocols (group 2-4) (16.2-17.1%) compared to the standard scan protocol (32.3%). Regression analysis of groups 2-4 showed better correlation with improved dose usage based on BMI (all P {<=} 0.001). Median image quality was ''excellent'' in groups 2-4 and ''good'' in group 1. Automated attenuation-based tube current adaptation in coronary calcium scoring is technically feasible, can decrease patient dose, and reduces variation in image noise as a sign of improved dose usage. (orig.)

  14. Presence of calcium-binding motifs in PilY1 homologs correlates with Ca-mediated twitching motility and evolutionary history across diverse bacteria.

    Science.gov (United States)

    Parker, Jennifer K; Cruz, Luisa F; Evans, Michael R; De La Fuente, Leonardo

    2015-02-01

    Twitching motility, involving type IV pili, is essential for host colonization and virulence of many pathogenic bacteria. Studies of PilY1, a tip-associated type IV pili protein, indicate that PilY1 functions as a switch between pilus extension and retraction, resulting in twitching motility. Recent work detected a calcium-binding motif in PilY1 of some animal bacterial pathogens and demonstrated that binding of calcium to PilY1 with this motif regulates twitching. Though studies of PilY1 in non-animal pathogens are limited, our group demonstrated that twitching motility in the plant pathogen Xylella fastidiosa, which contains three PilY1 homologs, is increased by calcium supplementation. A study was conducted to investigate the phylogenetic relationship between multiple PilY1 homologs, the presence of calcium-binding motifs therein, and calcium-mediated twitching motility across diverse bacteria. Strains analyzed contained one to three PilY1 homologs, but phylogenetic analyses indicated that PilY1 homologs containing the calcium-binding motif Dx[DN]xDGxxD are phylogenetically divergent from other PilY1 homologs. Plant-associated bacteria included in these analyses were then examined for a calcium-mediated twitching response. Results indicate that bacteria must have at least one PilY1 homolog containing the Dx[DN]xDGxxD motif to display a calcium-mediated increase in twitching motility, which likely reflects an adaption to environmental calcium concentrations. PMID:25688068

  15. Enlightenment on the aequorin-based platform for screening Arabidopsis stress sensory channels related to calcium signaling.

    Science.gov (United States)

    Yu, Zhiming; Taylor, Jemma L; He, Yue; Ni, Jun

    2015-01-01

    Free calcium ions (Ca(2+)) are an important signal molecule in response to a large array of external stimuli encountered by plants. Using the aequorin-based Ca(2+) recording system, tremendous progress has been made in understanding the Ca(2+) responses to biotic or abiotic stresses in dicotyledonous Arabidopsis. However, due to the lack of a similar detection system, little information has been obtained from the monocotyledonous rice (Oryza sativa). Recombinant aequorin has been introduced into rice, and the Ca(2+) responses to NaCl and H2O2 in rice roots were characterized. Although rice calcium signal sensor research has just started, the transgenic rice expressing aequorin provides a good platform to study rice adapted to different environmental conditions. PMID:26336841

  16. Enlightenment on the aequorin-based platform for screening Arabidopsis stress sensory channels related to calcium signaling.

    Science.gov (United States)

    Yu, Zhiming; Taylor, Jemma L; He, Yue; Ni, Jun

    2015-01-01

    Free calcium ions (Ca(2+)) are an important signal molecule in response to a large array of external stimuli encountered by plants. Using the aequorin-based Ca(2+) recording system, tremendous progress has been made in understanding the Ca(2+) responses to biotic or abiotic stresses in dicotyledonous Arabidopsis. However, due to the lack of a similar detection system, little information has been obtained from the monocotyledonous rice (Oryza sativa). Recombinant aequorin has been introduced into rice, and the Ca(2+) responses to NaCl and H2O2 in rice roots were characterized. Although rice calcium signal sensor research has just started, the transgenic rice expressing aequorin provides a good platform to study rice adapted to different environmental conditions.

  17. TENSILE STRENGTH AND CREEP RESISTANCE OF Mg-9Al-1ZnBASED ALLOYS WITH CALCIUM ADDITION

    Institute of Scientific and Technical Information of China (English)

    Y.S. Sun; W.M. Zhang; X.G. Min

    2001-01-01

    Small amount of calcium addition to the Mg-9Al-0. 8Zn-0.2Mn(AZ91) alloy resulted in the obvious influence on mechanical properties. The yield strength of the alloys increased with the increase of Ca addition and maximum strength was obtained from the alloy containing 0.15% of Ca. The creep resistance at the temperatures between 150-200°C was also significantly increased with Ca addition. The creep rate (at 200°C,50MPa) of the alloy with 0. 15% of Ca addition was one order of magnitude lower than that of the base alloy (AZ91). Microstructural observations revealed that the addition of calcium refined the microstructure and enhanced the thermal stability of the β precipitates, which accounted for the improvement of creep resistance at high temperatures.``

  18. Vehicle detection and tracking based on phase-correlation

    Institute of Scientific and Technical Information of China (English)

    Yi He(何毅); Xin Yang(杨新)

    2004-01-01

    This paper presents vehicle detection and tracking algorithms based on real-time background (RTB) and phase-correlation (PC) in the video sequence of urban highway with fixed camera. Firstly moving objects are obtained by subtracting RTB from serial images. After classification, PC is used to determine corresponding regions of moving objects between consecutive frames. The problems of vehicles' merging and splitting, sudden stop, and restart are also considered. Experiments show that the method is practical and can realize real-time detection and tracking of vehicles on highway.

  19. Long-term heat storage in calcium sulfoaluminate cement (CSA) based concrete

    Energy Technology Data Exchange (ETDEWEB)

    Kaufmann, Josef P.; Winnefeld, Frank [Empa Swiss Federal Laboratories for Materials Science and Technology, Duebendorf (Switzerland). Lab. for Concrete and Construction Chemistry

    2011-07-01

    In general, the selection of materials proposed for solar heat storage is based on one of two principal processes: sensible heat storage or latent heat storage. Sensible heat storage utilizes the specific heat capacity of a material, while latent heat storage is based on the change in enthalpy (heat content) associated with a phase change of the material. Long time sensible heat storage requires excellent thermal insulation whereas latent heat storage allows permanent (seasonal) storage without significant energy losses and any special insulation. Ettringite, one of the cement hydration products, exhibits a high dehydration enthalpy. Calcium sulfoaluminate cement based concrete containing a high amount of ettringite is henceproposed as an efficient latent heat storage material. Compared to conventional heat storage materials this innovative concrete mixture has a high loss-free storage energy density (> 100-150 kWh/m{sup 3}) which is much higher than the one of paraffin or the (loss-sensitive) sensible heat of water. Like common concrete the CSA-concrete is stable and even may carry loads. The dehydration of the CSA-concrete is achieved at temperatures below 100 C. The rehydration process occurs as soon as water (liquid or vapor) is added. In contrast to paraffin, the phase change temperature is not fixed and the latent heat may be recovered at any desired temperature. Furthermore the heat conductivity of this material is high, so that the energy transfer from/to an exchange medium is easy. Additionally CSA-concrete is not flammable and absolutely safe regarding any health aspects. The cost of such CSA-concrete isin the order of normal concrete. The main application is seen in house heating systems. Solar heat, mostly generated during the summer period by means of roof collectors, can be stored in CSA-concrete until the winter. A part or even the whole annual heatingenergy may be produced and saved locally by the householder himself. Additional applications may be

  20. An efficient calcium phosphate nanoparticle-based nonviral vector for gene delivery

    Directory of Open Access Journals (Sweden)

    Liu YC

    2011-04-01

    Full Text Available Yachun Liu1,2,*, Tao Wang1,*, Fangli He1,*, Qian Liu1,*, Dexi Zhang2, Shuanglin Xiang1, Shengpei Su2, Jian Zhang11Key Laboratory of Protein Chemistry and Developmental Biology, Ministry of Education of China, College of Life Sciences; 2Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research and Key Laboratory of Sustainable Resources Processing and Advanced Materials of Hunan Province, Ministry of Education of China, College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha, Hunan, China*These authors contributed equally to this workBackground: Smaller nanoparticles facilitate the delivery of DNA into cells through endocytosis and improve transfection efficiency. The aim of this study was to determine whether protamine sulfate-coated calcium phosphate (PS-CaP could stabilize particle size and enhance transfection efficiency.Methods: pEGFP-C1 green fluorescence protein was employed as an indicator of transfection efficiency. Atomic force microscopy was used to evaluate the morphology and the size of the particles, and an MTT assay was introduced to detect cell viability and inhibition. The classical calcium phosphate method was used as the control.Results: Atomic force microscopy images showed that the PS-CaP were much smaller than classical calcium phosphate particles. In 293 FT, HEK 293, and NIH 3T3 cells, the transfection efficiency of PS-CaP was higher than for the classical calcium phosphate particles. The difference in efficiencies implies that the smaller nanoparticles may promote the delivery of DNA into cells through endocytosis and could improve transfection efficiency. In addition, PS-CaP could be used to transfect HEK 293 cells after one week of storage at 4°C with a lesser extent of efficiency loss compared with classical calcium phosphate, indicating that protamine sulfate may increase the stability of calcium phosphate nanoparticles. The cell viability inhibition assay indicated that

  1. Integration of calcium and chemical looping combustion using composite CaO/CuO-based materials.

    Science.gov (United States)

    Manovic, Vasilije; Anthony, Edward J

    2011-12-15

    Calcium looping cycles (CaL) and chemical looping combustion (CLC) are two new, developing technologies for reduction of CO(2) emissions from plants using fossil fuels for energy production, which are being intensively examined. Calcium looping is a two-stage process, which includes oxy-fuel combustion for sorbent regeneration, i.e., generation of a concentrated CO(2) stream. This paper discuss the development of composite materials which can use copper(II)-oxide (CuO) as an oxygen carrier to provide oxygen for the sorbent regeneration stage of calcium looping. In other words, the work presented here involves integration of calcium looping and chemical looping into a new class of postcombustion CO(2) capture processes designated as integrated CaL and CLC (CaL-CLC or Ca-Cu looping cycles) using composite pellets containing lime (CaO) and CuO together with the addition of calcium aluminate cement as a binder. Their activity was tested in a thermogravimetric analyzer (TGA) during calcination/reduction/oxidation/carbonation cycles. The calcination/reduction typically was performed in methane (CH(4)), and the oxidation/carbonation stage was carried out using a gas mixture containing both CO(2) and O(2). It was confirmed that the material synthesized is suitable for the proposed cycles; with the very favorable finding that reduction/oxidation of the oxygen carrier is complete. Various schemes for the Ca-Cu looping process have been explored here that would be compatible with these new composite materials, along with some different possibilities for flow directions among carbonator, calciner, and air reactor.

  2. Mouse neuroblastoma cell-based model and the effect of epileptic events on calcium oscillations and neural spikes

    Science.gov (United States)

    Kim, Suhwan; Jung, Unsang; Baek, Juyoung; Lee, Sangwon; Jung, Woonggyu; Kim, Jeehyun; Kang, Shinwon

    2013-01-01

    Recently, mouse neuroblastoma cells have been considered as an attractive model for the study of human neurological and prion diseases, and they have been intensively used as a model system in different areas. For example, the differentiation of neuro2a (N2A) cells, receptor-mediated ion current, and glutamate-induced physiological responses have been actively investigated with these cells. These mouse neuroblastoma N2A cells are of interest because they grow faster than other cells of neural origin and have a number of other advantages. The calcium oscillations and neural spikes of mouse neuroblastoma N2A cells in epileptic conditions are evaluated. Based on our observations of neural spikes in these cells with our proposed imaging modality, we reported that they can be an important model in epileptic activity studies. We concluded that mouse neuroblastoma N2A cells produce epileptic spikes in vitro in the same way as those produced by neurons or astrocytes. This evidence suggests that increased levels of neurotransmitter release due to the enhancement of free calcium from 4-aminopyridine causes the mouse neuroblastoma N2A cells to produce epileptic spikes and calcium oscillations.

  3. Mouse neuroblastoma cell based model and the effect of epileptic events on calcium oscillations and neural spikes

    Science.gov (United States)

    Kim, Suhwan; Baek, Juyeong; Jung, Unsang; Lee, Sangwon; Jung, Woonggyu; Kim, Jeehyun; Kang, Shinwon

    2013-05-01

    Recently, Mouse neuroblastoma cells are considered as an attractive model for the study of human neurological and prion diseases, and intensively used as a model system in different areas. Among those areas, differentiation of neuro2a (N2A) cells, receptor mediated ion current, and glutamate induced physiological response are actively investigated. The reason for the interest to mouse neuroblastoma N2A cells is that they have a fast growing rate than other cells in neural origin with a few another advantages. This study evaluated the calcium oscillations and neural spikes recording of mouse neuroblastoma N2A cells in an epileptic condition. Based on our observation of neural spikes in mouse N2A cell with our proposed imaging modality, we report that mouse neuroblastoma N2A cells can be an important model related to epileptic activity studies. It is concluded that the mouse neuroblastoma N2A cells produce the epileptic spikes in vitro in the same way as produced by the neurons or the astrocytes. This evidence advocates the increased and strong level of neurotransmitters release by enhancement in free calcium using the 4-aminopyridine which causes the mouse neuroblastoma N2A cells to produce the epileptic spikes and calcium oscillation.

  4. Traffic Prediction Based on Correlation of Road Sections

    Directory of Open Access Journals (Sweden)

    Xiaodan Huang

    2013-10-01

    Full Text Available Road section data packet is very necessary for the estimation and prediction in short-time traffic condition. However, previous researches on this problem are lack of quantitative analysis. A section correlation analyzing method with traffic flow microwave data is proposed for this problem. It is based on the metric multidimensional scaling theory. With a dissimilarity matrix, scalar product matrix can be calculated. Subsequently, a reconstructing matrix of section traffic flow could be got with principal components factor analysis, which could display section groups in low dimension. It is verified that the new method is reliable and effective. After that, Auto Regressive Moving Average (A RMA model is used for forecasting traffic flow and lane occupancy. Finally, a simulated example has shown that the technique is effective and exact. The theoretical analysis indicates that the forecasting model and algorithms have a broad prospect for practical application.  

  5. Windows Volatile Memory Forensics Based on Correlation Analysis

    Directory of Open Access Journals (Sweden)

    Xiaolu Zhang

    2014-03-01

    Full Text Available In this paper, we present an integrated memory forensic solution for multiple Windows memory images. By calculation, the method can find out the correlation degree among the processes of volatile memory images and the hidden clues behind the events of computers, which is usually difficult to be obtained and easily ignored by analyzing one single memory image and forensic investigators. In order to test the validity, we performed an experiment based on two hosts' memory image which contains criminal incidents. According to the experimental result, we find that the event chains reconstructed by our method are similar to the actual actions in the criminal scene. Investigators can review the digital crime scenario which is contained in the data set by analyzing the experimental results. This paper is aimed at finding the valid actions with illegal attempt and making the memory analysis not to be utterly dependent on the operating system and relevant experts.

  6. Spanning Trees and bootstrap reliability estimation in correlation based networks

    CERN Document Server

    Tumminello, M; Lillo, F; Micciché, S; Mantegna, R N

    2006-01-01

    We introduce a new technique to associate a spanning tree to the average linkage cluster analysis. We term this tree as the Average Linkage Minimum Spanning Tree. We also introduce a technique to associate a value of reliability to links of correlation based graphs by using bootstrap replicas of data. Both techniques are applied to the portfolio of the 300 most capitalized stocks traded at New York Stock Exchange during the time period 2001-2003. We show that the Average Linkage Minimum Spanning Tree recognizes economic sectors and sub-sectors as communities in the network slightly better than the Minimum Spanning Tree does. We also show that the average reliability of links in the Minimum Spanning Tree is slightly greater than the average reliability of links in the Average Linkage Minimum Spanning Tree.

  7. Calcium ion channel and epilepsy

    Institute of Scientific and Technical Information of China (English)

    Yudan Lü; Weihong Lin; Dihui Ma

    2006-01-01

    OBJECTIVE: To review the relationship between calcium ion channel and epilepsy for well investigating the pathogenesis of epilepsy and probing into the new therapeutic pathway of epilepsy.DATA SOURCES: A computer-based online research Calcium ion channel and epilepsy related articles published between January 1994 and December 2006 in the CKNI and Wanfang database with the key words of "calcium influxion, epilepsy, calcium-channel blocker". The language was limited to Chinese. At the same time,related articles published between January 1993 and December 2006 in Pubmed were searched for on online with the key words of "calcium influxion, epilepsy" in English.STUDY SELECTION: The materials were selected firstly. Inclusive criteria: ① Studies related to calcium ion channel and the pat1hogenesis of epilepsy. ② Studies on the application of calcium ion channel blocker in the treatment of epilepsy. Exclusive criteria: repetitive or irrelated studies.DATA EXTRACTION: According to the criteria, 123 articles were retrieved and 93 were excluded due to repetitive or irrelated studies. Altogether 30 articles met the inclusive criteria, 11 of them were about the structure and characters of calcium ion channel, 10 about calcium ion channel and the pathogenesis of epilepsy and 9 about calcium blocker and the treatment of epilepsy.DATA SYNTHESIS: Calcium ion channels mainly consist of voltage dependent calcium channel and receptor operated calcium channel. Depolarization caused by voltage gating channel-induced influxion is the pathological basis of epileptic attack, and it is found in many studies that many anti-epileptic drugs have potential and direct effect to rivalizing voltage-dependent calcium ion channel.CONCLUSION: Calcium influxion plays an important role in the seizure of epilepsy. Some calcium antagonists seen commonly are being tried in the clinical therapy of epilepsy that is being explored, not applied in clinical practice. If there are enough evidences to

  8. Influence of Calcium Carbonate Fillers on the Properties of Recycled Poly(e-caprolactone) Based Thermoplastic Polyurethane

    OpenAIRE

    Vitalija BETINGYTĖ; Žukienė, Kristina; Virginija JANKAUSKAITĖ; Milašienė, Daiva; Kazys Vytautas MICKUS; Ada GULBINIENĖ

    2012-01-01

    In this work the effects of different crystallographic modifications of calcium carbonate (CaCO3) filler on the melt flow, mechanical properties, hydrolytic degradation, and shape memory behaviour of recycled low-temperature poly(e-caprolactone)-based polyurethane (rTPU) were evaluated. Composites were prepared by two-roll milling varying filler content from 2 wt % to 6 wt %. It was found that at temperature range from 20 °C to 50 °C CaCO3 fillers do not change Young’s modulus, they decrease ...

  9. Correlation between air pollution and crystal pattern of calcium oxalate in plant leaves of street trees in Itami City. [Ginkgo biloba; Salix babylonica; Aphananthe aspera; Robinia pseudoacacia

    Energy Technology Data Exchange (ETDEWEB)

    Umemoto, K.; Tatsumi, S.

    1975-01-01

    A characteristic difference in calcium oxalate crystal patterns in leaves of roadside trees planted in relatively unpolluted northern parts of Itami City and in parts of the city polluted by automobile exhaust was discovered. The species of trees examined were Ginkgo biloba, Salix babylonica, Aphananthe aspera, Robinia pseudoacacia, and Poplar. The leaves of trees grown in relatively less air polluted areas displayed crystal aggregates of calcium oxalate (50-80 micron) that were arranged in rows on both sides of the central vein; some scattered crystal aggregates between veins were observed. Trees grown in air polluted areas showed irregular crystal patterns and more scattering of the crystals between veins. The cause of the observed differences in the pattern of crystal aggregates was attributed to the difference in metabolism of trees under different environmental conditions. Air pollutants disturb the normal metabolism of the tree and cause hyperproduction of calcium oxalate.

  10. Traffic Sign Recognition System based on Cambridge Correlator Image Comparator

    Directory of Open Access Journals (Sweden)

    J. Turan

    2012-06-01

    Full Text Available Paper presents basic information about application of Optical Correlator (OC, specifically Cambridge Correlator, in system to recognize of traffic sign. Traffic Sign Recognition System consists of three main blocks, Preprocessing, Optical Correlator and Traffic Sign Identification. The Region of Interest (ROI is defined and chosen in preprocessing block and then goes to Optical Correlator, where is compared with database of Traffic Sign. Output of Optical Correlation is correlation plane, which consist of highly localized intensities, know as correlation peaks. The intensity of spots provides a measure of similarity and position of spots, how images (traffic signs are relatively aligned in the input scene. Several experiments have been done with proposed system and results and conclusion are discussed.

  11. Statistical Analyses of Optimum Partial Replacement of Cement by Fly Ash Based on Complete Consumption of Calcium Hydroxide

    Directory of Open Access Journals (Sweden)

    Ouypornprasert Winai

    2016-01-01

    Full Text Available The objectives of this technical paper were to propose the optimum partial replacement of cement by fly ash based on the complete consumption of calcium hydroxide from hydration reactions of cement and the long-term strength activity index based on equivalent calcium silicate hydrate as well as the propagation of uncertainty due to randomness inherent in main chemical compositions in cement and fly ash. Firstly the hydration- and pozzolanic reactions as well as stoichiometry were reviewed. Then the optimum partial replacement of cement by fly ash was formulated. After that the propagation of uncertainty due to main chemical compositions in cement and fly ash was discussed and the reliability analyses for applying the suitable replacement were reviewed. Finally an applicability of the concepts mentioned above based on statistical data of materials available was demonstrated. The results from analyses were consistent with the testing results by other researchers. The results of this study provided guidelines of suitable utilization of fly ash for partial replacement of cement. It was interesting to note that these concepts could be extended to optimize partial replacement of cement by other types of pozzolan which were described in the other papers of the authors.

  12. Estimating genetic correlations based on phenotypic data: a simulation-based method

    Indian Academy of Sciences (India)

    Elias Zintzaras

    2011-04-01

    Knowledge of genetic correlations is essential to understand the joint evolution of traits through correlated responses to selection, a difficult and seldom, very precise task even with easy-to-breed species. Here, a simulation-based method to estimate genetic correlations and genetic covariances that relies only on phenotypic measurements is proposed. The method does not require any degree of relatedness in the sampled individuals. Extensive numerical results suggest that the propose method may provide relatively efficient estimates regardless of sample sizes and contributions from common environmental effects.

  13. Production and characterization of setting hydraulic cements based on calcium phosphate; Obtencao e caracterizacao de cimentos de fosfato de calcio de pega hidraulica

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Luci C. de; Rigo, Eliana C.S.; Santos, Luis A dos; Boschi, Anselmo Ortega [Sao Carlos Univ., SP (Brazil). Dept. de Engenharia de Materiais; Carrodeguas, Raul G. [Universidad de La Habana, Habana (Cuba). Centro de Biomateriales

    1997-12-31

    Setting hydraulic cements based on calcium phosphate has risen great interest in scientific literature during recent years due to their total bio compatibility and to the fact that they harden `in situ`, providing easy handling and adaptation to the shape and dimensions of the defect which requires correction, differently from the predecessors, the calcium phosphate ceramics (Hydroxy apatite, {beta}-tri calcium phosphate, biphasic, etc) in the shape of dense or porous blocks and grains. In the work, three calcium-phosphate cement compositions were studied. The resulting compositions were characterized according to the following aspects: setting times, pH, mechanical resistance, crystalline phases, microstructure and solubility in SBF (Simulated Body Fluid). The results show a potential use for the compositions. (author) 6 figs., 4 tabs.

  14. Formation and properties of biocoatings based on wollastonite and calcium phosphates

    International Nuclear Information System (INIS)

    Wollastonite-calcium phosphate coatings were produced on titanium substrates by micro-arc oxidation method. There presented the study of influence of oxidation voltage, process duration and pulse duration on properties of the coatings such as thickness, surface morphology and surface roughness. The morphology and phase composition of the coatings were studied by scanning electron microscopy and X-ray diffraction methods. It was found that biocoatings with large amount of wollastonite particles were deposited under minimum oxidation voltage of 130–150 V. The structural elements with a spherical or plate-like shape were formed on the coating surface depending on micro-arc oxidation parameters

  15. Formation and properties of biocoatings based on wollastonite and calcium phosphates

    Energy Technology Data Exchange (ETDEWEB)

    Sedelnikova, M. B., E-mail: smb@ispms.tsc.ru; Sharkeev, Yu. P., E-mail: sharkeev@ispms.tsc.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); National Research Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation); Komarova, E. G., E-mail: katerina@ispms.tsc.ru; Tolkacheva, T. V., E-mail: tolkacheva@ispms.tsc.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation)

    2015-10-27

    Wollastonite-calcium phosphate coatings were produced on titanium substrates by micro-arc oxidation method. There presented the study of influence of oxidation voltage, process duration and pulse duration on properties of the coatings such as thickness, surface morphology and surface roughness. The morphology and phase composition of the coatings were studied by scanning electron microscopy and X-ray diffraction methods. It was found that biocoatings with large amount of wollastonite particles were deposited under minimum oxidation voltage of 130–150 V. The structural elements with a spherical or plate-like shape were formed on the coating surface depending on micro-arc oxidation parameters.

  16. Diets Based on Sugar Cane Treated with Calcium Oxide for Lambs

    OpenAIRE

    G.G.P. Carvalho; R. Garcia; A.J.V. Pires; R.R. Silva; Detmann, E.; Filho, A. Eustaquio; Ribeiro, L. S. O.; L.M. Carvalho

    2013-01-01

    This experiment was conducted to evaluate the intake, nutrient apparent digestibility and the effect of total collection days (two and four days) on apparent digestibility estimates for lambs fed diets containing sugar cane treated with calcium oxide (CaO). Eight Santa Inês castrated male lambs with a 16.6±1.8 kg body weight were used. The lambs were distributed in two 4×4 Latin squares, with four experimental periods of 14 d each. The animals were kept in 1.2 m2 individual pens, and the inta...

  17. Shifting-and-Scaling Correlation Based Biclustering Algorithm.

    Science.gov (United States)

    Ahmed, Hasin Afzal; Mahanta, Priyakshi; Bhattacharyya, Dhruba Kumar; Kalita, Jugal Kumar

    2014-01-01

    The existence of various types of correlations among the expressions of a group of biologically significant genes poses challenges in developing effective methods of gene expression data analysis. The initial focus of computational biologists was to work with only absolute and shifting correlations. However, researchers have found that the ability to handle shifting-and-scaling correlation enables them to extract more biologically relevant and interesting patterns from gene microarray data. In this paper, we introduce an effective shifting-and-scaling correlation measure named Shifting and Scaling Similarity (SSSim), which can detect highly correlated gene pairs in any gene expression data. We also introduce a technique named Intensive Correlation Search (ICS) biclustering algorithm, which uses SSSim to extract biologically significant biclusters from a gene expression data set. The technique performs satisfactorily with a number of benchmarked gene expression data sets when evaluated in terms of functional categories in Gene Ontology database. PMID:26357059

  18. The GCaMP3 – A GFP-based calcium sensor for imaging calcium dynamics in the human malaria parasite Plasmodium falciparum

    OpenAIRE

    Borges-Pereira, Lucas; Campos, Bruna R.K.L.; Garcia, Celia R. S.

    2014-01-01

    Calcium (Ca2+) signaling pathways are vital for all eukaryotic cells. It is well established that changes in Ca2+ concentration can modulate several physiological processes such as muscle contraction, neurotransmitter secretion and metabolic regulation (Giacomello et al. (2007) [1], Rizzuto and Pozzan (2003) [2]). In the complex life cycle of Plasmodium falciparum, the causative agent of human malaria, Ca2+ is involved in the processes of protein secretion, motility, cell invasion, cell progr...

  19. Dynamically reconfigurable multiple beam illumination based on optical correlation

    DEFF Research Database (Denmark)

    Glückstad, Jesper; Palima, Darwin; Dam, Jeppe Seidelin;

    2009-01-01

    We adapt concepts from optical correlation and optical pattern recognition to propose a method for generating reconfigurable multiple spots with high efficiency. The generated spots correspond to the correlation spikes in optical pattern recognition. In pattern recognition, optimizing...... the correlation filter is constrained by the target pattern to be detected. The reverse process of light projection grants the freedom to optimize both the target pattern and the correlation filters. Combined with contemporary spatial light modulation technologies, the proposed method can yield dynamically...... reconfigurable optical patterns with high efficiency for optical micromanipulation and other applications....

  20. Development of calcium phosphate based apatite from hen’s eggshell

    Indian Academy of Sciences (India)

    K Prabakaran; A Balamurugan; S Rajeswari

    2005-04-01

    Stoichiometric hydroxyapatite with Ca/P molar ratio, 1.67, was synthesized using hen’s eggshell as calcium source and phosphoric acid by precipitation method. Conventional EDTA titration and gravimetric methods were adopted to estimate the amount of calcium and phosphorous, respectively. Fourier-transform infrared (FT–IR) and X-ray diffraction (XRD) techniques were employed to investigate the formation of the HAP phase. Thermal analysis (TG–DTA) was carried out to investigate the thermal stability of HAP powder. FT–IR spectra show the characteristic peaks for phosphate and hydroxyl groups. XRD results reveal that the major characteristic peaks of HAP appear in the region of approximately 26°, 28°, 29°, 30–35°, 39°, 46°, 49° and 50° (2) and also indicate that there are no occurrences of secondary phases during HAP formation. TG–DTA result depicts that the synthesized HAP was stable up to 1300°C.

  1. Atlas-based diffusion tensor imaging correlates of executive function

    Science.gov (United States)

    Nowrangi, Milap A.; Okonkwo, Ozioma; Lyketsos, Constantine; Oishi, Kenichi; Mori, Susumu; Albert, Marilyn; Mielke, Michelle M.

    2015-01-01

    Impairment in executive function (EF) is commonly found in Alzheimer’s Dementia (AD) and Mild Cognitive Impairment (MCI). Atlas-based Diffusion Tensor Imaging (DTI) methods may be useful in relating regional integrity to EF measures in MCI and AD. 66 participants (25 NC, 22 MCI, and 19 AD) received DTI scans and clinical evaluation. DTI scans were applied to a pre-segmented atlas and fractional anisotropy (FA) and mean diffusivity (MD) were calculated. ANOVA was used to assess group differences in frontal, parietal, and cerebellar regions. For regions differing between groups (p<0.01), linear regression examined the relationship between EF scores and regional FA and MD. Anisotropy and diffusivity in frontal and parietal lobe white matter (WM) structures were associated with EF scores in MCI and only frontal lobe structures in AD. EF was more strongly associated with FA than MD. The relationship between EF and anisotropy and diffusivity was strongest in MCI. These results suggest that regional WM integrity is compromised in MCI and AD and that FA may be a better correlate of EF than MD. PMID:25318544

  2. A study of combined evaluation of suppliers based on correlation

    Directory of Open Access Journals (Sweden)

    Heting Qiu

    2013-03-01

    Full Text Available Purpose: The Selection of logistics service providers is an important issue in supply chain management. But different evaluation methods may lead to different results, which could cause inconsistent conclusions. This paper makes use of a new perspective to combine with a variety of methods to eliminate the deviation of different single evaluation methods. Design/methodology/approach: This paper expounds the application of the combined evaluation method based on correlation. Entropy method, factor analysis, grey colligation evaluation and AHP have been used for research. Findings: According to the evaluate result, the ranking of suppliers obtained by each method have obvious differences. The result shows that combined evaluation method can eliminate the deviation of different single evaluation methods. Originality/value: The combined evaluation method makes up for the defects of single evaluation methods and obtains a result that is more stable and creditable with smaller deviation. This study can provide the enterprise leaders with more scientific method to select their cooperative companies. 

  3. Comparative evaluation of the remineralizing efficacy of calcium sodium phosphosilicate agent and fluoride based on quantitative and qualitative analysis

    Directory of Open Access Journals (Sweden)

    Saranya Mony

    2015-01-01

    Full Text Available Background: Calcium sodium phosphosilicate (NovaMin is an agent that is claimed to release calcium and phosphate ions intraorally to help the self-repair process of enamel. It is used extensively as a desensitizing agent, but the chemical reactions that occur may promote apatite formation enhancing remineralization. The present study was undertaken to evaluate the ability of NovaMin to remineralize an experimentally induced demineralized lesion. The evaluation was done based on the quantitative and qualitative analysis of enamel over the period of 15 and 30 days. Materials and Methods: A sample of 120 noncarious premolar teeth extracted for orthodontic reasons were used for the study. Baseline data for hardness, Ca/PO 4 , and surface characteristics before and after demineralization process was obtained. All the teeth were brushed twice daily at 12 h interval with the test agents using a powered toothbrush for 2 min. The samples were tested on the 15 th and 30 th day. Results: Calcium phosphate ratio and hardness in both the groups improved during the study period. Fluoride group showed higher values for Ca/PO 4 and hardness but was not statistically significant with the P > 0.05. Scanning electron microscope pictures showed that the deposition of the material over the decalcified enamel is more smoother and uniform with NovaMin and more irregular with fluoride. Relevance: NovaMin is found to be as effective in improving the Ca/PO 4 ratio and hardness in a demineralized enamel as fluoride. Hence, it can be a new alternate material for remineralization of enamel with less toxic effects compared to fluorides.

  4. Correlation methods of base-level cycle based on wavelet neural network

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The authors discussed the method of wavelet neural network (WNN) for correlation of base-level cycle. A new vectored method of well log data was proposed. Through the training with the known data set, the WNN can remenber the cycle pattern characteristic of the well log curves. By the trained WNN to identify the cycle pattern in the vectored log data, the ocrrelation process among the well cycles was completed. The application indicates that it is highly efficient and reliable in base-level cycle correlation.

  5. Calcium Carbonate

    Science.gov (United States)

    ... before being swallowed; do not swallow them whole. Drink a full glass of water after taking either the regular or chewable tablets or capsules. Some liquid forms of calcium carbonate must be shaken well before use.Do not ...

  6. Calcium Calculator

    Science.gov (United States)

    ... Latvia - Lebanon - Libya - Lithuania - Luxembourg - Macedonia, Republic of - Malaysia - Malta - Mexico - Moldova - Morocco - Netherlands - New Zealand - Nigeria - ... and Statistics Popular content Calcium content of common foods What is Osteoporosis? The Board Introduction to Bone ...

  7. Calcium Electroporation

    DEFF Research Database (Denmark)

    Frandsen, Stine Krog; Gibot, Laure; Madi, Moinecha;

    2015-01-01

    BACKGROUND: Calcium electroporation describes the use of high voltage electric pulses to introduce supraphysiological calcium concentrations into cells. This promising method is currently in clinical trial as an anti-cancer treatment. One very important issue is the relation between tumor cell kill...... efficacy-and normal cell sensitivity. METHODS: Using a 3D spheroid cell culture model we have tested the effect of calcium electroporation and electrochemotherapy using bleomycin on three different human cancer cell lines: a colorectal adenocarcinoma (HT29), a bladder transitional cell carcinoma (SW780......), and a breast adenocarcinoma (MDA-MB231), as well as on primary normal human dermal fibroblasts (HDF-n). RESULTS: The results showed a clear reduction in spheroid size in all three cancer cell spheroids three days after treatment with respectively calcium electroporation (p

  8. Injectable Hydrogel Composite Based Gelatin-PEG and Biphasic Calcium Phosphate Nanoparticles for Bone Regeneration

    Science.gov (United States)

    Van, Thuy Duong; Tran, Ngoc Quyen; Nguyen, Dai Hai; Nguyen, Cuu Khoa; Tran, Dai Lam; Nguyen, Phuong Thi

    2016-05-01

    Gelatin hydrogels have recently attracted much attention for tissue regeneration because of their biocompatibility. In this study, we introduce poly-ethylene glycol (PEG)—grafted gelatin containing tyramine moieties which have been utilized for in situ enzyme-mediated hydrogel preparation. The hydrogel can be used to load nanoparticles of biphasic calcium phosphate, a mixture of hydroxyapatite and β-tricalcium phosphate, and forming injectable bio-composites. Proton nuclear magnetic resonance (1H NMR) spectra indicated that tyramine-functionalized polyethylene glycol-nitrophenyl carbonate ester was conjugated to the gelatin. The hydrogel composite was rapidly formed in situ (within a few seconds) in the presence of horseradish peroxidase and hydrogen peroxide. In vitro experiments with bio-mineralization on the hydrogel composite surfaces was well-observed after 2 weeks soaking in simulated body fluid solution. The obtained results indicated that the hydrogel composite could be a potential injectable material for bone regeneration.

  9. Calcium Ion Detection Using Miniaturized InN-based Ion Sensitive Field Effect Transistors

    Directory of Open Access Journals (Sweden)

    Kun-Wei Kao

    2012-03-01

    Full Text Available An Ultrathin (~10 nm InN ion sensitive field effect transistor (ISFET with gate regions functionalized with phosphotyrosine (p-Tyr is proposed to detect calcium ions (Ca2+ in aqueous solution. The ISFET was miniaturized to a chip size of 1.1 mm by 1.5 mm and integrated at the tip of a hypodermic injection needle (18 G for real-time and continuous monitoring. The sensor shows a current variation ratio of 1.11% with per decade change of Ca2+ and a detection limit of 10-6 M. The response time of 5 sec. reveals its great potential for accomplishing fast detection in chemical and physiological sensing applications. The sensor would be applied in medical diagnosis and used to monitor continuous and real-time variations of Ca2+ levels in human blood in the near future.

  10. Effect of cetyl trimethyl ammonium bromide concentration on structure, morphology and carbon dioxide adsorption capacity of calcium hydroxide based sorbents

    Science.gov (United States)

    Hlaing, Nwe Ni; Vignesh, K.; Sreekantan, Srimala; Pung, Swee-Yong; Hinode, Hirofumi; Kurniawan, Winarto; Othman, Radzali; Thant, Aye Aye; Mohamed, Abdul Rahman; Salim, Chris

    2016-02-01

    Calcium hydroxide (Ca(OH)2) has been proposed as an important material for industrial, architectural, and environmental applications. In this study, calcium acetate was used as a precursor and cetyl trimethyl ammonium bromide (CTAB) was used as a surfactant to synthesize Ca(OH)2 based adsorbents for carbon dioxide (CO2) capture. The effect of CTAB concentration (0.2-0.8 M) on the structure, morphology and CO2 adsorption performance of Ca(OH)2 was studied in detail. The synthesized samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), BET surfaced area and thermogravimetry-differential thermal analysis (TG-DTA) techniques. The phase purity, crystallite size, Brunauer-Emmett-Teller (BET) surface area and CO2 adsorption performance of Ca(OH)2 precursor adsorbents were significantly increased when the concentration of CTAB was increased. XRD results showed that pure Ca(OH)2 phase was obtained at the CTAB concentration of 0.8 M. TGA results exhibited that 0.8 M of CTAB-assisted Ca(OH)2 precursor adsorbent possessed a residual carbonation conversion of ∼56% after 10 cycles.

  11. Biopolymer-induced calcium phosphate scaling in membrane-based water treatment systems: Langmuir model films studies.

    Science.gov (United States)

    Dahdal, Yara N; Oren, Yoram; Schwahn, Dietmar; Pipich, Vitaliy; Herzberg, Moshe; Ying, Wang; Kasher, Roni; Rapaport, Hanna

    2016-07-01

    Biofouling and scaling on reverse osmosis (RO) or nanofiltration (NF) membranes during desalination of secondary and tertiary effluents pose an obstacle that limits the reuse of wastewater. In this study we explored the mineral scaling induced by biopolymers originated from bacterial biofilms: bovine serum albumin (BSA), fibrinogen, lysozyme and alginic acid, as well as an extracts of extracellular polymeric substances (EPS) from bio-fouled RO membranes from wastewater treatment facility. Mineralization studies were performed on Langmuir films of the biopolymers deposited at the interface of a solution simulating RO desalination of secondary-treated wastewater effluents. All studied biopolymers and EPS induced heterogeneous mineralization of mainly calcium phosphate. Using IR spectroscopy coupled with systematic quantitative analysis of the surface pressure versus molecular-area isotherms, we determined the mineralization tendencies of the biopolymers to be in the order of: fibrinogen>lysozyme>BSA>alginic acid. The biopolymers and EPS studied here were found to be accelerators of calcium-phosphate mineralization. This study demonstrates the utilization of Langmuir surface-pressure area isotherms and a model solution in quantitatively assessing the mineralization tendencies of various molecular components of EPS in context of membrane-based water treatment systems. PMID:27015648

  12. Performance of VBLAST Systems Based on Spatial Correlated MIMO Channels

    Institute of Scientific and Technical Information of China (English)

    WANG Zhong-peng; QIU Zhong-yuan; WU Wei-ling

    2004-01-01

    Vertically-layered Bell Laboratories Layered Space-Time (VBLAST) is one of the most promising techniques for realizing high spectral efficiencies over wireless link. In previously published work, the performance of VBLAST has been primarily investigated in uncorrelated Rayleigh fading channels. However in real environments some correlation between antenna elements can be presented. In this paper, we study the impact of transmit correlation on the performance of VBLAST systems. Finally we provide simulation results demonstrating the impact of spatial fading correlation on the symbol error rate of VBLAST.

  13. Sampling of General Correlators in Worm Algorithm-based Simulations

    CERN Document Server

    Rindlisbacher, Tobias; de Forcrand, Philippe

    2016-01-01

    Using the complex $\\phi^4$-model as a prototype for a system which is simulated by a (bosonic) worm algorithm, we show that not only the charged correlator $$, but also more general correlators such as $$ or $$ as well as condensates like $$ can be measured at every step of the Monte Carlo evolution of the worm instead of on closed-worm configurations only. The method generalizes straightforwardly to other systems simulated by (bosonic) worms, such as spin or sigma models.

  14. Sampling of general correlators in worm-algorithm based simulations

    Science.gov (United States)

    Rindlisbacher, Tobias; Åkerlund, Oscar; de Forcrand, Philippe

    2016-08-01

    Using the complex ϕ4-model as a prototype for a system which is simulated by a worm algorithm, we show that not only the charged correlator , but also more general correlators such as or , as well as condensates like , can be measured at every step of the Monte Carlo evolution of the worm instead of on closed-worm configurations only. The method generalizes straightforwardly to other systems simulated by worms, such as spin or sigma models.

  15. Post-prandial changes in plasma mineral levels in rainbow trout fed a complete plant ingredient based diet and the effect of supplemental di-calcium phosphate

    NARCIS (Netherlands)

    Antony Jesu Prabhu, P.; Schrama, J.W.; Mariojouls, C.; Godin, S.; Fontagné-Dicharry, S.; Geurden, I.; Surget, A.; Bouyssiere, B.; Kaushik, S.J.

    2014-01-01

    Post-prandial changes in plasma mineral levels and utilisation of minerals in rainbow trout fed complete plant ingredient based diets with or without supplemental di-calcium phosphate (DCP) were studied over an 8 week period. Three diets were used: diet M was FM and fish oil (FO) based diet (control

  16. Correlation-based Transition Modeling for External Aerodynamic Flows

    Science.gov (United States)

    Medida, Shivaji

    Conventional turbulence models calibrated for fully turbulent boundary layers often over-predict drag and heat transfer on aerodynamic surfaces with partially laminar boundary layers. A robust correlation-based model is developed for use in Reynolds-Averaged Navier-Stokes simulations to predict laminar-to-turbulent transition onset of boundary layers on external aerodynamic surfaces. The new model is derived from an existing transition model for the two-equation k-omega Shear Stress Transport (SST) turbulence model, and is coupled with the one-equation Spalart-Allmaras (SA) turbulence model. The transition model solves two transport equations for intermittency and transition momentum thickness Reynolds number. Experimental correlations and local mean flow quantities are used in the model to account for effects of freestream turbulence level and pressure gradients on transition onset location. Transition onset is triggered by activating intermittency production using a vorticity Reynolds number criterion. In the new model, production and destruction terms of the intermittency equation are modified to improve consistency in the fully turbulent boundary layer post-transition onset, as well as ensure insensitivity to freestream eddy viscosity value specified in the SA model. In the original model, intermittency was used to control production and destruction of turbulent kinetic energy. Whereas, in the new model, only the production of eddy viscosity in SA model is controlled, and the destruction term is not altered. Unlike the original model, the new model does not use an additional correction to intermittency for separation-induced transition. Accuracy of drag predictions are improved significantly with the use of the transition model for several two-dimensional single- and multi-element airfoil cases over a wide range of Reynolds numbers. The new model is able to predict the formation of stable and long laminar separation bubbles on low-Reynolds number airfoils that

  17. Coupled-cluster based basis sets for valence correlation calculations

    Science.gov (United States)

    Claudino, Daniel; Gargano, Ricardo; Bartlett, Rodney J.

    2016-03-01

    Novel basis sets are generated that target the description of valence correlation in atoms H through Ar. The new contraction coefficients are obtained according to the Atomic Natural Orbital (ANO) procedure from CCSD(T) (coupled-cluster singles and doubles with perturbative triples correction) density matrices starting from the primitive functions of Dunning et al. [J. Chem. Phys. 90, 1007 (1989); ibid. 98, 1358 (1993); ibid. 100, 2975 (1993)] (correlation consistent polarized valence X-tuple zeta, cc-pVXZ). The exponents of the primitive Gaussian functions are subject to uniform scaling in order to ensure satisfaction of the virial theorem for the corresponding atoms. These new sets, named ANO-VT-XZ (Atomic Natural Orbital Virial Theorem X-tuple Zeta), have the same number of contracted functions as their cc-pVXZ counterparts in each subshell. The performance of these basis sets is assessed by the evaluation of the contraction errors in four distinct computations: correlation energies in atoms, probing the density in different regions of space via (-3 ≤ n ≤ 3) in atoms, correlation energies in diatomic molecules, and the quality of fitting potential energy curves as measured by spectroscopic constants. All energy calculations with ANO-VT-QZ have contraction errors within "chemical accuracy" of 1 kcal/mol, which is not true for cc-pVQZ, suggesting some improvement compared to the correlation consistent series of Dunning and co-workers.

  18. Sound card based digital correlation detection of weak photoelectrical signals

    Energy Technology Data Exchange (ETDEWEB)

    Tang Guanghui; Wang Jiangcheng [Department of Physics, Normal College of Shihezi University, Xinjiang 832003 (China)

    2005-09-01

    A simple and low-cost digital correlation method is proposed to investigate weak photoelectrical signals, using a high-speed photodiode as detector, which is directly connected to a programmably triggered sound card analogue-to-digital converter and a personal computer. Two testing experiments, autocorrelation detection of weak flickering signals from a computer monitor under background of noisy outdoor stray light and cross-correlation measurement of the surface velocity of a motional tape, are performed, showing that the results are reliable and the method is easy to implement.

  19. Nanoscale calcium aluminate coated graphite for improved performance of alumina based monolithic refractory composite

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Sol–gel Ca-doped γ-Al2O3 accomplished graphite retention. • Nanocoating considerably improved matrix-aggregate bonding. • Less porous simulated matrix upgraded slag resistance. - Abstract: The synthesis and properties of high alumina castable containing nanostructured calcium aluminate coated graphite were studied in terms of slag resistance and overall physical characteristics. Raman spectroscopy, BET surface area and field emission scanning electron microscopy (FESEM) were performed to exclusively understand the coating characteristics and its compatibility in refractory composite. The coating not only secured graphite in castable for prolonged period but also noticeably improved matrix to aggregate contact. The microstructural aspects of castables were investigated, with special emphasis on a representative matrix prepared and infiltrated with slag at elevated temperature. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) of fired composite containing surface-treated graphite was quite prospective. It circumvented the problems of incorporating as-received graphite in castables and should be in the attention of refractory researchers and producers

  20. Nanoscale calcium aluminate coated graphite for improved performance of alumina based monolithic refractory composite

    Energy Technology Data Exchange (ETDEWEB)

    Mukhopadhyay, S., E-mail: msunanda_cct@yahoo.co.in

    2013-07-15

    Graphical abstract: - Highlights: • Sol–gel Ca-doped γ-Al{sub 2}O{sub 3} accomplished graphite retention. • Nanocoating considerably improved matrix-aggregate bonding. • Less porous simulated matrix upgraded slag resistance. - Abstract: The synthesis and properties of high alumina castable containing nanostructured calcium aluminate coated graphite were studied in terms of slag resistance and overall physical characteristics. Raman spectroscopy, BET surface area and field emission scanning electron microscopy (FESEM) were performed to exclusively understand the coating characteristics and its compatibility in refractory composite. The coating not only secured graphite in castable for prolonged period but also noticeably improved matrix to aggregate contact. The microstructural aspects of castables were investigated, with special emphasis on a representative matrix prepared and infiltrated with slag at elevated temperature. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) of fired composite containing surface-treated graphite was quite prospective. It circumvented the problems of incorporating as-received graphite in castables and should be in the attention of refractory researchers and producers.

  1. In Vivo Functional Brain Imaging Approach Based on Bioluminescent Calcium Indicator GFP-aequorin.

    Science.gov (United States)

    Lark, Arianna R; Kitamoto, Toshihiro; Martin, Jean-René

    2016-01-08

    Functional in vivo imaging has become a powerful approach to study the function and physiology of brain cells and structures of interest. Recently a new method of Ca(2+)-imaging using the bioluminescent reporter GFP-aequorin (GA) has been developed. This new technique relies on the fusion of the GFP and aequorin genes, producing a molecule capable of binding calcium and - with the addition of its cofactor coelenterazine - emitting bright light that can be monitored through a photon collector. Transgenic lines carrying the GFP-aequorin gene have been generated for both mice and Drosophila. In Drosophila, the GFP-aequorin gene has been placed under the control of the GAL4/UAS binary expression system allowing for targeted expression and imaging within the brain. This method has subsequently been shown to be capable of detecting both inward Ca(2+)-transients and Ca(2+)-released from inner stores. Most importantly it allows for a greater duration in continuous recording, imaging at greater depths within the brain, and recording at high temporal resolutions (up to 8.3 msec). Here we present the basic method for using bioluminescent imaging to record and analyze Ca(2+)-activity within the mushroom bodies, a structure central to learning and memory in the fly brain.

  2. Improving accuracy in coronary lumen segmentation via explicit calcium exclusion, learning-based ray detection and surface optimization

    Science.gov (United States)

    Lugauer, Felix; Zhang, Jingdan; Zheng, Yefeng; Hornegger, Joachim; Kelm, B. Michael

    2014-03-01

    Invasive cardiac angiography (catheterization) is still the standard in clinical practice for diagnosing coronary artery disease (CAD) but it involves a high amount of risk and cost. New generations of CT scanners can acquire high-quality images of coronary arteries which allow for an accurate identification and delineation of stenoses. Recently, computational fluid dynamics (CFD) simulation has been applied to coronary blood flow using geometric lumen models extracted from CT angiography (CTA). The computed pressure drop at stenoses proved to be indicative for ischemia-causing lesions, leading to non-invasive fractional flow reserve (FFR) derived from CTA. Since the diagnostic value of non-invasive procedures for diagnosing CAD relies on an accurate extraction of the lumen, a precise segmentation of the coronary arteries is crucial. As manual segmentation is tedious, time-consuming and subjective, automatic procedures are desirable. We present a novel fully-automatic method to accurately segment the lumen of coronary arteries in the presence of calcified and non-calcified plaque. Our segmentation framework is based on three main steps: boundary detection, calcium exclusion and surface optimization. A learning-based boundary detector enables a robust lumen contour detection via dense ray-casting. The exclusion of calcified plaque is assured through a novel calcium exclusion technique which allows us to accurately capture stenoses of diseased arteries. The boundary detection results are incorporated into a closed set formulation whose minimization yields an optimized lumen surface. On standardized tests with clinical data, a segmentation accuracy is achieved which is comparable to clinical experts and superior to current automatic methods.

  3. CHAOTIC CONTROL OF NONLINEAR SYSTEMS BASED ON IMPROVED CORRELATIVITY

    Institute of Scientific and Technical Information of China (English)

    Zhou Xiaoan; Zhang Jihong

    2003-01-01

    Chaotic sequences are basically ergodic random sequences. By improving correlativity of a chaotic signal, the chaotic dynamic system can be controlled to converge to its equilibrium point and, more significantly, to its multi-periodic orbits. Mathematical theory analysis is carried out and some computer simulation results are provided to support such controllability of the chaotic Henon system and the discrete coupled map lattice.

  4. Clustering and information in correlation based financial networks

    Science.gov (United States)

    Onnela, J.-P.; Kaski, K.; Kertész, J.

    2004-03-01

    Networks of companies can be constructed by using return correlations. A crucial issue in this approach is to select the relevant correlations from the correlation matrix. In order to study this problem, we start from an empty graph with no edges where the vertices correspond to stocks. Then, one by one, we insert edges between the vertices according to the rank of their correlation strength, resulting in a network called asset graph. We study its properties, such as topologically different growth types, number and size of clusters and clustering coefficient. These properties, calculated from empirical data, are compared against those of a random graph. The growth of the graph can be classified according to the topological role of the newly inserted edge. We find that the type of growth which is responsible for creating cycles in the graph sets in much earlier for the empirical asset graph than for the random graph, and thus reflects the high degree of networking present in the market. We also find the number of clusters in the random graph to be one order of magnitude higher than for the asset graph. At a critical threshold, the random graph undergoes a radical change in topology related to percolation transition and forms a single giant cluster, a phenomenon which is not observed for the asset graph. Differences in mean clustering coefficient lead us to conclude that most information is contained roughly within 10% of the edges.

  5. Thermal Care of Functional Dyspepsia Based on Bicarbonate-Sulphate-Calcium Water: A Sequential Clinical Trial

    Directory of Open Access Journals (Sweden)

    Giuseppe Rocca

    2007-01-01

    Full Text Available Drug treatment of functional dyspepsia is often unsatisfactory. We assessed the efficacy of a bicarbonate-sulphate-calcium thermal water cycle of 12 days, in patients with functional dyspepsia. Patients with functional dyspepsia were sent by their general practitioners to 12 days of treatment with thermal water, 200–400 ml in the morning, at temperature of 33°C (91.4 F and were evaluated on a strict intention to treat basis. Four efficacy endpoints were analyzed as follows: (i reduction of the global symptoms score, (ii reduction of intensity to a level not interfering with everyday activities, (iii specific efficacy on ulcer-like or dysmotility-like dyspepsia and (iv esophageal or abdominal-associated symptoms. Statistical significance was reached for all three primary outcomes after the first 29 consecutive patients. Thermal water reduced the global symptom score, reduced intensity of symptoms to a level not interfering with everyday activity, but was unable to completely suppress all symptoms. A parallel effect emerged for ulcer-like and dyspepsia-like subgroups. The effect on heartburn and abdominal symptoms was not significant, suggesting a specific effect of the water on the gastric and duodenal wall. The Roma II criteria identify a natural kind of dyspepsia that improves with thermal water. Ulcer-like and dysmotility-like are not therapeutically distinguishable subgroups. Patients with dominant esophageal or abdominal symptoms should receive a different therapy. Sequential methods are very effective for the evaluation of traditional care practices and should be considered preliminary and integrative to randomized controlled trials in this context.

  6. Thermal Care of Functional Dyspepsia Based on Bicarbonate-Sulphate-Calcium Water: A Sequential Clinical Trial

    Science.gov (United States)

    Dioni, Federico; Rocca, Nadia; Oliveri, Filippo; Brunetto, Maurizia R; Bonino, Ferruccio

    2007-01-01

    Drug treatment of functional dyspepsia is often unsatisfactory. We assessed the efficacy of a bicarbonate-sulphate-calcium thermal water cycle of 12 days, in patients with functional dyspepsia. Patients with functional dyspepsia were sent by their general practitioners to 12 days of treatment with thermal water, 200–400 ml in the morning, at temperature of 33°C (91.4 F) and were evaluated on a strict intention to treat basis. Four efficacy endpoints were analyzed as follows: (i) reduction of the global symptoms score, (ii) reduction of intensity to a level not interfering with everyday activities, (iii) specific efficacy on ulcer-like or dysmotility-like dyspepsia and (iv) esophageal or abdominal-associated symptoms. Statistical significance was reached for all three primary outcomes after the first 29 consecutive patients. Thermal water reduced the global symptom score, reduced intensity of symptoms to a level not interfering with everyday activity, but was unable to completely suppress all symptoms. A parallel effect emerged for ulcer-like and dyspepsia-like subgroups. The effect on heartburn and abdominal symptoms was not significant, suggesting a specific effect of the water on the gastric and duodenal wall. The Roma II criteria identify a natural kind of dyspepsia that improves with thermal water. Ulcer-like and dysmotility-like are not therapeutically distinguishable subgroups. Patients with dominant esophageal or abdominal symptoms should receive a different therapy. Sequential methods are very effective for the evaluation of traditional care practices and should be considered preliminary and integrative to randomized controlled trials in this context. PMID:17965771

  7. 2D Satellite Image Registration Using Transform Based and Correlation Based Methods

    OpenAIRE

    Dr. H.B. Kekre, Dr. Tanuja K. Sarode, Ms. Ruhina B. Karani

    2012-01-01

    Image registration is the process of geometrically aligning one image to another image of the same scene taken from different viewpoints or by different sensors. It is a fundamental image processing technique and is very useful in integrating information from different sensors, finding changes in images taken at different times and inferring three-dimensional information from stereo images. Image registration can be done by using two matching method: transform based methods and correlation ba...

  8. NIRS-BASED CORTICAL ACTIVATION ANALYSIS BY TEMPORAL CROSS CORRELATION

    Directory of Open Access Journals (Sweden)

    Raul Fernandez-Rojas

    2016-02-01

    Full Text Available In this study we present a method of signal processing to determine dominant channels in near infrared spectroscopy (NIRS. To compare measuring channels and identify delays between them, cross correlation is computed. Furthermore, to find out possible dominant channels, a visual inspection was performed. The outcomes demonstrated that the visual inspection exhibited evoked-related activations in the primary somatosensory cortex (S1 after stimulation which is consistent with comparable studies and the cross correlation study discovered dominant channels on both cerebral hemispheres. The analysis also showed a relationship between dominant channels and adjacent channels. For that reason, our results present a new method to identify dominant regions in the cerebral cortex using near-infrared spectroscopy. These findings have also implications in the decrease of channels by eliminating irrelevant channels for the experiment.

  9. A blind modulation recognition algorithm based on cyclic spectral correlation

    Institute of Scientific and Technical Information of China (English)

    Gao Yulong; Zhang Zhongzhao

    2007-01-01

    Cyclic spectral correlation above the bifrequency plane for the received signal was calculated by the strip spectral correlation algorithm (SSCA)and then was normalized. The result was expressed by matrix. The sum of error- square was computed between corresponding elements for the theoretical sampling matrix of all kinds of modulated signals and calculated matrix . The modulation type was recognized by exploiting the minimum value of the sum of error- square . No extracted characteristic parameter and prior information are needed for identifying the modulation type compared to the conventional methods. In addition, the new method extends the recognition scope and has high recognition probability at low SNR . The simulation results obtained by means of Monter- Carlo method proved the presented algorithm.

  10. CHAOTIC CONTROL OF NONLINEAR SYSTEMS BASED ON IMPROVED CORRELATIVITY

    Institute of Scientific and Technical Information of China (English)

    ZhouZiaoan; ZhangJihong

    2003-01-01

    Chaotic sequences are basically ergodic random esquences.By improving correlativity of a chaotic signal,the chaotic dynamic system can be controlled to converge to its equilibrium point and,more significantly,to its multi-periodic orbits.Mathematical theory analysis is carried out and some computer simulation results are provided to support such controllability of the chaotic Henon system and the discrete coupled map lattice.

  11. Preparation and Characterization of Ni-Doped Calcium Silicate Hydrate Based on Steel Slag: Adsorption Capacity for Rhodamine B from Aqueous Solution

    OpenAIRE

    2015-01-01

    Calcium silicate hydrate based on steel slag (SCSH) and Ni-doped SCSH (NSCSH) were synthesized under specific hydrothermal conditions at saturated vapor pressure and 185°C for 7 hours. The structure and morphology of SCSH and NSCSH were characterized by XRD, SEM, and N2 adsorption/desorption. SCSH mainly consisted of amorphous calcium silicate hydrate gel (C-S-H gel) together with some flake-like tobermorite and NSCSH consisted of crystalline tobermorite and xonotlite. The addition of Ni(NO3)...

  12. Chord Recognition Based on Temporal Correlation Support Vector Machine

    Directory of Open Access Journals (Sweden)

    Zhongyang Rao

    2016-05-01

    Full Text Available In this paper, we propose a method called temporal correlation support vector machine (TCSVM for automatic major-minor chord recognition in audio music. We first use robust principal component analysis to separate the singing voice from the music to reduce the influence of the singing voice and consider the temporal correlations of the chord features. Using robust principal component analysis, we expect the low-rank component of the spectrogram matrix to contain the musical accompaniment and the sparse component to contain the vocal signals. Then, we extract a new logarithmic pitch class profile (LPCP feature called enhanced LPCP from the low-rank part. To exploit the temporal correlation among the LPCP features of chords, we propose an improved support vector machine algorithm called TCSVM. We perform this study using the MIREX’09 (Music Information Retrieval Evaluation eXchange Audio Chord Estimation dataset. Furthermore, we conduct comprehensive experiments using different pitch class profile feature vectors to examine the performance of TCSVM. The results of our method are comparable to the state-of-the-art methods that entered the MIREX in 2013 and 2014 for the MIREX’09 Audio Chord Estimation task dataset.

  13. Calcium and bones

    Science.gov (United States)

    Bone strength and calcium ... calcium (as well as phosphorus) to make healthy bones. Bones are the main storage site of calcium in ... your body does not absorb enough calcium, your bones can get weak or will not grow properly. ...

  14. Calcium carbonate overdose

    Science.gov (United States)

    Tums overdose; Calcium overdose ... Calcium carbonate can be dangerous in large amounts. ... Some products that contain calcium carbonate are certain: ... and mineral supplements Other products may also contain calcium ...

  15. Get Enough Calcium

    Science.gov (United States)

    ... Calcium Print This Topic En español Get Enough Calcium Browse Sections The Basics Overview Foods and Vitamins ... 2 of 4 sections Take Action! Take Action: Calcium Sources Protect your bones – get plenty of calcium ...

  16. Reducing nitrous oxide emissions by changing N fertiliser use from calcium ammonium nitrate (CAN) to urea based formulations.

    Science.gov (United States)

    Harty, M A; Forrestal, P J; Watson, C J; McGeough, K L; Carolan, R; Elliot, C; Krol, D; Laughlin, R J; Richards, K G; Lanigan, G J

    2016-09-01

    The accelerating use of synthetic nitrogen (N) fertilisers, to meet the world's growing food demand, is the primary driver for increased atmospheric concentrations of nitrous oxide (N2O). The IPCC default emission factor (EF) for N2O from soils is 1% of the N applied, irrespective of its form. However, N2O emissions tend to be higher from nitrate-containing fertilisers e.g. calcium ammonium nitrate (CAN) compared to urea, particularly in regions, which have mild, wet climates and high organic matter soils. Urea can be an inefficient N source due to NH3 volatilisation, but nitrogen stabilisers (urease and nitrification inhibitors) can improve its efficacy. This study evaluated the impact of switching fertiliser formulation from calcium ammonium nitrate (CAN) to urea-based products, as a potential mitigation strategy to reduce N2O emissions at six temperate grassland sites on the island of Ireland. The surface applied formulations included CAN, urea and urea with the urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT) and/or the nitrification inhibitor dicyandiamide (DCD). Results showed that N2O emissions were significantly affected by fertiliser formulation, soil type and climatic conditions. The direct N2O emission factor (EF) from CAN averaged 1.49% overall sites, but was highly variable, ranging from 0.58% to 3.81. Amending urea with NBPT, to reduce ammonia volatilisation, resulted in an average EF of 0.40% (ranging from 0.21 to 0.69%)-compared to an average EF of 0.25% for urea (ranging from 0.1 to 0.49%), with both fertilisers significantly lower and less variable than CAN. Cumulative N2O emissions from urea amended with both NBPT and DCD were not significantly different from background levels. Switching from CAN to stabilised urea formulations was found to be an effective strategy to reduce N2O emissions, particularly in wet, temperate grassland. PMID:27155080

  17. Reducing nitrous oxide emissions by changing N fertiliser use from calcium ammonium nitrate (CAN) to urea based formulations.

    Science.gov (United States)

    Harty, M A; Forrestal, P J; Watson, C J; McGeough, K L; Carolan, R; Elliot, C; Krol, D; Laughlin, R J; Richards, K G; Lanigan, G J

    2016-09-01

    The accelerating use of synthetic nitrogen (N) fertilisers, to meet the world's growing food demand, is the primary driver for increased atmospheric concentrations of nitrous oxide (N2O). The IPCC default emission factor (EF) for N2O from soils is 1% of the N applied, irrespective of its form. However, N2O emissions tend to be higher from nitrate-containing fertilisers e.g. calcium ammonium nitrate (CAN) compared to urea, particularly in regions, which have mild, wet climates and high organic matter soils. Urea can be an inefficient N source due to NH3 volatilisation, but nitrogen stabilisers (urease and nitrification inhibitors) can improve its efficacy. This study evaluated the impact of switching fertiliser formulation from calcium ammonium nitrate (CAN) to urea-based products, as a potential mitigation strategy to reduce N2O emissions at six temperate grassland sites on the island of Ireland. The surface applied formulations included CAN, urea and urea with the urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT) and/or the nitrification inhibitor dicyandiamide (DCD). Results showed that N2O emissions were significantly affected by fertiliser formulation, soil type and climatic conditions. The direct N2O emission factor (EF) from CAN averaged 1.49% overall sites, but was highly variable, ranging from 0.58% to 3.81. Amending urea with NBPT, to reduce ammonia volatilisation, resulted in an average EF of 0.40% (ranging from 0.21 to 0.69%)-compared to an average EF of 0.25% for urea (ranging from 0.1 to 0.49%), with both fertilisers significantly lower and less variable than CAN. Cumulative N2O emissions from urea amended with both NBPT and DCD were not significantly different from background levels. Switching from CAN to stabilised urea formulations was found to be an effective strategy to reduce N2O emissions, particularly in wet, temperate grassland.

  18. Combining Correlation-Based and Reward-Based Learning in Neural Control for Policy Improvement

    DEFF Research Database (Denmark)

    Manoonpong, Poramate; Kolodziejski, Christoph; Wörgötter, Florentin;

    2013-01-01

    Classical conditioning (conventionally modeled as correlation-based learning) and operant conditioning (conventionally modeled as reinforcement learning or reward-based learning) have been found in biological systems. Evidence shows that these two mechanisms strongly involve learning about...... policy, i.e., it allows the controller to learn stabilizing the pole in the largest domain of initial conditions compared to the results obtained when using a single learning mechanism. This model can also find a successful control policy for goal-directed behavior, i.e., the robot can effectively learn...

  19. Comparison of Subset-Based Local and Finite Element-Based Global Digital Image Correlation

    KAUST Repository

    Pan, Bing

    2015-02-12

    Digital image correlation (DIC) techniques require an image matching algorithm to register the same physical points represented in different images. Subset-based local DIC and finite element-based (FE-based) global DIC are the two primary image matching methods that have been extensively investigated and regularly used in the field of experimental mechanics. Due to its straightforward implementation and high efficiency, subset-based local DIC has been used in almost all commercial DIC packages. However, it is argued by some researchers that FE-based global DIC offers better accuracy because of the enforced continuity between element nodes. We propose a detailed performance comparison between these different DIC algorithms both in terms of measurement accuracy and computational efficiency. Then, by measuring displacements of the same calculation points using the same calculation algorithms (e.g., correlation criterion, initial guess estimation, subpixel interpolation, optimization algorithm and convergence conditions) and identical calculation parameters (e.g., subset or element size), the performances of subset-based local DIC and two FE-based global DIC approaches are carefully compared in terms of measurement error and computational efficiency using both numerical tests and real experiments. A detailed examination of the experimental results reveals that, when subset (element) size is not very small and the local deformation within a subset (element) can be well approximated by the shape function used, standard subset-based local DIC approach not only provides better results in measured displacements, but also demonstrates much higher computation efficiency. However, several special merits of FE-based global DIC approaches are indicated.

  20. Color pattern recognition based on the joint fractional Fourier transform correlator

    Institute of Scientific and Technical Information of China (English)

    Weimin Jin; Yupei Zhang

    2007-01-01

    A new system of multi-channel single-output joint fractional Fourier transform correlator (JFRTC) for color pattern recognition is proposed based on the conventional system of multi-channel single-output joint transform correlator (JTC). The theoretical analysis and optical experiments are performed. With this method, one can obtain three correlation peaks at the output plane which show a pair of desired cross-correlation peaks and one auto-correlation peak. In comparison, the conventional system leads to more correlation peaks playing a noise role in color pattern recognition.

  1. Cardiovascular Effects of Calcium Supplements

    Directory of Open Access Journals (Sweden)

    Ian R. Reid

    2013-07-01

    Full Text Available Calcium supplements reduce bone turnover and slow the rate of bone loss. However, few studies have demonstrated reduced fracture incidence with calcium supplements, and meta-analyses show only a 10% decrease in fractures, which is of borderline statistical and clinical significance. Trials in normal older women and in patients with renal impairment suggest that calcium supplements increase the risk of cardiovascular disease. To further assess their safety, we recently conducted a meta-analysis of trials of calcium supplements, and found a 27%–31% increase in risk of myocardial infarction, and a 12%–20% increase in risk of stroke. These findings are robust because they are based on pre-specified analyses of randomized, placebo-controlled trials and are consistent across the trials. Co-administration of vitamin D with calcium does not lessen these adverse effects. The increased cardiovascular risk with calcium supplements is consistent with epidemiological data relating higher circulating calcium concentrations to cardiovascular disease in normal populations. There are several possible pathophysiological mechanisms for these effects, including effects on vascular calcification, vascular cells, blood coagulation and calcium-sensing receptors. Thus, the non-skeletal risks of calcium supplements appear to outweigh any skeletal benefits, and are they appear to be unnecessary for the efficacy of other osteoporosis treatments.

  2. Pilot study of automated bullet signature identification based on topography measurements and correlations.

    Science.gov (United States)

    Chu, Wei; Song, John; Vorburger, Theodore; Yen, James; Ballou, Susan; Bachrach, Benjamin

    2010-03-01

    A procedure for automated bullet signature identification is described based on topography measurements using confocal microscopy and correlation calculation. Automated search and retrieval systems are widely used for comparison of firearms evidence. In this study, 48 bullets fired from six different barrel manufacturers are classified into different groups based on the width class characteristic for each land engraved area of the bullets. Then the cross-correlation function is applied both for automatic selection of the effective correlation area, and for the extraction of a 2D bullet profile signature. Based on the cross-correlation maximum values, a list of top ranking candidates against a ballistics signature database of bullets fired from the same model firearm is developed. The correlation results show a 9.3% higher accuracy rate compared with a currently used commercial system based on optical reflection. This suggests that correlation results can be improved using the sequence of methods described here. PMID:20102451

  3. CaO-based pellets supported by calcium aluminate cements for high-temperature CO2 capture.

    Science.gov (United States)

    Manovic, Vasilije; Anthony, Edward J

    2009-09-15

    The development of highly efficient CaO-based pellet sorbents, using inexpensive raw materials (limestones) or the spent sorbent from CO2 capture cycles, and commercially available calcium aluminate cements (CA-14, CA-25, Secar 51, and Secar 80), is described here. The pellets were prepared using untreated powdered limestones or their corresponding hydrated limes and were tested for their CO2 capture carrying capacities for 30 carbonation/calcination cycles in a thermogravimetric analyzer (TGA). Their morphology was also investigated by scanning electron microscopy (SEM) and their compositions before and after carbonation/calcination cycleswere determined by X-ray diffraction (XRD). Pellets prepared in this manner showed superior behavior during CO2 capture cycles compared to natural sorbents, with the highest conversions being > 50% after 30 cycles. This improved performance was attributed to the resulting substructure of the sorbent particles, i.e., a porous structure with nanoparticles incorporated. During carbonation/calcination cycles mayenite (Ca12Al14O33) was formed, which is believed to be responsible for the favorable performance of synthetic CaO-based sorbents doped with alumina compounds. An added advantage of the pellets produced here is their superior strength, offering the possibility of using them in fluidized bed combustion (FBC) systems with minimal sorbent loss due to attrition. PMID:19806751

  4. Calcium paradox and calcium entry blockers

    NARCIS (Netherlands)

    Ruigrok, T.J.C.; Slade, A.M.; Nayler, W.G.; Meijler, F.L.

    1984-01-01

    Reperfusion of isolated hearts with calcium-containing solution after a short period of calcium-free perfusion results in irreversible cell damage (calcium paradox). This phenomenon is characterized by an excessive influx of calcium into the cells, the rapid onset of myocardial contracture, exhausti

  5. Design and implementation of photon correlator based on C8051F

    Science.gov (United States)

    Shen, Jin; Li, Yuming; Liu, Wei; Yang, Yan; Cheng, Yanting

    2008-02-01

    Correlation techniques are widely used to extract spectral information from light scattering and other stochastic processes. Within the photon correlation system, the correlating operation must work at a high speed. In this paper, a photon correlator based on microcontroller C8051F was developed. In the photon correlator, the work of counting and scratch is completed by the two 4-bits binary adder 74F161, which is connected to form an 8-bits adder., and the correlation operation of every channel is carried out by the software of C8051F. By probably choosing high speed devices counting of 10ns in width pulses can be counted. The correlation operations including multiplying and addition operation of 56 channels with the circulation program within 3μs were made in interrupt service routine of the C8051F. The work in this paper can be applied in the ultra-fine particle sizing with photon correlation spectroscopy.

  6. A new Expert Finding model based on Term Correlation Matrix

    Directory of Open Access Journals (Sweden)

    Ehsan Pornour

    2015-09-01

    Full Text Available Due to the enormous volume of unstructured information available on the Web and inside organization, finding an answer to the knowledge need in a short time is difficult. For this reason, beside Search Engines which don’t consider users individual characteristics, Recommender systems were created which use user’s previous activities and other individual characteristics to help users find needed knowledge. Recommender systems usage is increasing every day. Expert finder systems also by introducing expert people instead of recommending information to users have provided this facility for users to ask their questions form experts. Having relation with experts not only causes information transition, but also with transferring experiences and inception causes knowledge transition. In this paper we used university professors academic resume as expert people profile and then proposed a new expert finding model that recommends experts to users query. We used Term Correlation Matrix, Vector Space Model and PageRank algorithm and proposed a new hybrid model which outperforms conventional methods. This model can be used in internet environment, organizations and universities that experts have resume dataset.

  7. Elemental Content of Calcium Oxalate Stones from a Canine Model of Urinary Stone Disease.

    Directory of Open Access Journals (Sweden)

    David W Killilea

    Full Text Available One of the most common types of urinary stones formed in humans and some other mammals is composed of calcium oxalate in ordered hydrated crystals. Many studies have reported a range of metals other than calcium in human stones, but few have looked at stones from animal models such as the dog. Therefore, we determined the elemental profile of canine calcium oxalate urinary stones and compared it to reported values from human stones. The content of 19 elements spanning 7-orders of magnitude was quantified in calcium oxalate stones from 53 dogs. The elemental profile of the canine stones was highly overlapping with human stones, indicating similar inorganic composition. Correlation and cluster analysis was then performed on the elemental profile from canine stones to evaluate associations between the elements and test for potential subgrouping based on elemental content. No correlations were observed with the most abundant metal calcium. However, magnesium and sulfur content correlated with the mineral hydration form, while phosphorous and zinc content correlated with the neuter status of the dog. Inter-elemental correlation analysis indicated strong associations between barium, phosphorous, and zinc content. Additionally, cluster analysis revealed subgroups within the stones that were also based primarily on barium, phosphorous, and zinc. These data support the use of the dog as a model to study the effects of trace metal homeostasis in urinary stone disease.

  8. Virtual non-contrast CT using dual energy spectral CT: Feasibility of coronary artery calcium scoring

    Energy Technology Data Exchange (ETDEWEB)

    Song, In Young; Yi, Jeong Geun; Park, Jeong Hee [Dept. of Radiology, Konkuk University School of Medicine, Seoul (Korea, Republic of); Lee, Sung Mok; Lee, Kyung Soo; Chung, Myung Jin [Dept. of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

    2016-06-15

    To evaluate the feasibility of coronary artery calcium scoring based on three virtual noncontrast-enhanced (VNC) images derived from single-source spectral dual-energy CT (DECT) as compared with true noncontrast-enhanced (TNC) images. This prospective study was conducted with the approval of our Institutional Review Board. Ninety-seven patients underwent noncontrast CT followed by contrast-enhanced chest CT using single-source spectral DECT. Iodine eliminated VNC images were reconstructed using two kinds of 2-material decomposition algorithms (material density iodine-water pair [MDW], material density iodine-calcium pair [MDC]) and a material suppressed algorithm (material suppressed iodine [MSI]). Two readers independently quantified calcium on VNC and TNC images. The Spearman correlation coefficient test and Bland-Altman method were used for statistical analyses. Coronary artery calcium scores from all three VNC images showed excellent correlation with those from the TNC images (Spearman's correlation coefficient [ρ] = 0.94, 0.88, and 0.89 for MDW, MDC, and MSI, respectively; p < 0.001 for all pairs). Measured coronary calcium volumes from VNC images also correlated well with those from TNC images (ρ = 0.92, 0.87, and 0.91 for MDW, MDC, and MSI, respectively; p < 0.001 for all pairs). Among the three VNC images, coronary calcium from MDW correlated best with that from TNC. The coronary artery calcium scores and volumes were significantly lower from the VNC images than from the TNC images (p < 0.001 for all pairs). The use of VNC images from contrast-enhanced CT using dual-energy material decomposition/suppression is feasible for coronary calcium scoring. The absolute value from VNC tends to be smaller than that from TNC.

  9. Intrusion detection method based on nonlinear correlation measure

    NARCIS (Netherlands)

    Ambusaidi, Mohammed A.; Tan, Zhiyuan; He, Xiangjian; Nanda, Priyadarsi; Lu, Liang Fu; Jamdagni, Aruna

    2014-01-01

    Cyber crimes and malicious network activities have posed serious threats to the entire internet and its users. This issue is becoming more critical, as network-based services, are more widespread and closely related to our daily life. Thus, it has raised a serious concern in individual internet user

  10. 血铅、镉、钙、锌及铜水平与孕妇稽留流产的相关性分析%Correlation of blood lead, cadmium, calcium, zinc and copper levels with missed abortion

    Institute of Scientific and Technical Information of China (English)

    朱军; 梅茹; 姚超

    2015-01-01

    目的:探讨血铅、镉、钙、锌及铜水平与孕妇稽留流产的相关性。方法:选取2012年6月至2014年12月我院收治的稽留流产孕妇172例为研究对象(研究组),同期随机选取200例正常孕妇为对照(对照组),检测两组患者血铅、镉、钙、锌及铜水平。结果:与对照组比较,研究组孕妇血铅、镉水平较高(P<0.05),而钙、锌水平较低(P<0.05),多元回归分析显示:孕妇血铅、镉、钙、锌及铜水平与多种因素相关(职业性铅暴露、镉暴露、被动吸烟、生活饮食习惯、孕期保健等因素)(P<0.05);多因素Logistic回归分析显示:高血铅、镉、孕妇职业铅暴露、孕妇吸烟、孕期生殖系统感染、近期家庭装潢为孕妇稽留流产危险因素(P<0.05);而血锌、血钙、补锌、孕期补充维生素为孕妇稽留流产保护性因素(P<0.05)。结论:血铅、镉、钙、锌与孕妇出现稽留流产可能存在一定相关性,值得临床关注。%Objective:To investigate the correlation between blood lead, cadmium, calcium, zinc and copper levels in pregnant women with missed abortion.Methods: A total of 172 cases of pregnant women with missed abortion admitted into our hospital from June 2012 to December 2014 were selected as subjects (research group), meanwhile 200 cases of normal pregnant women were randomly selected as controls (control group); blood lead, cadmium, calcium, zinc and copper were detected in both groups of patients.Results:Compared with the normal group, blood lead and cadmium levels in research group were higher (P<0.05), while the calcium and zinc levels were lower (P<0.05), multiple regression analysis showed that blood lead, cadmium, calcium, zinc and copper levels were related to a variety of factors (occupational exposure to lead, cadmium exposure, passive smoking, diet habits, prenatal care) (P<0.05); Logistic regression analysis showed that high blood lead, cadmium, maternal

  11. A Correlational Encoder Decoder Architecture for Pivot Based Sequence Generation

    OpenAIRE

    SAHA, AMRITA; Khapra, Mitesh M.; Chandar, Sarath; Rajendran, Janarthanan; Cho, Kyunghyun

    2016-01-01

    Interlingua based Machine Translation (MT) aims to encode multiple languages into a common linguistic representation and then decode sentences in multiple target languages from this representation. In this work we explore this idea in the context of neural encoder decoder architectures, albeit on a smaller scale and without MT as the end goal. Specifically, we consider the case of three languages or modalities X, Z and Y wherein we are interested in generating sequences in Y starting from inf...

  12. An Eavesdropping Detecting Approach Based on Mode-Mode Correlation

    Institute of Scientific and Technical Information of China (English)

    XIONG Jin; ZENG Gui-Hua; ZHOU Nan-Run

    2005-01-01

    @@ We find that second-order coherence as well as a Hanbury-Brown-Twiss intensity interferometer may provide an optimal approach for eavesdropping detection in the quantum key distribution based on two-mode squeezed'vacuum states. With this approach, eavesdropping can be easily detected without sacrificing extra secret bits as the test key. In addition, the efficiency of the quantum key distribution protocol is enhanced greatly.

  13. The prevalence of chondrocalcinosis (CC) of the acromioclavicular (AC) joint on chest radiographs and correlation with calcium pyrophosphate dihydrate (CPPD) crystal deposition disease

    Science.gov (United States)

    Carrera, Guillermo; Baynes, Keith; Mautz, Alan; DuBois, Melissa; Cerniglia, Ross; Ryan, Lawrence M.

    2016-01-01

    Digital imaging combined with picture archiving and communication system (PACS) access allows detailed image retrieval and magnification. Calcium pyrophosphate dihydrate (CPPD) crystals preferentially deposit in fibrocartilages, the cartilage of the acromioclavicular (AC) joint being one such structure. We sought to determine if examination of the AC joints on magnified PACS imaging of chest films would be useful in identifying chondrocalcinosis (CC). Retrospective radiographic readings and chart reviews involving 1,920 patients aged 50 or more who had routine outpatient chest radiographs over a 4-month period were performed. Knee radiographs were available for comparison in 489 patients. Medical records were reviewed to abstract demographics, chest film reports, and diagnoses. AC joint CC was identified in 1.1 % (21/1,920) of consecutive chest films. Patients with AC joint CC were 75 years of age versus 65.4 in those without CC (phistory of CPPD crystal deposition disease than those without AC joint CC (14 versus 1 %, p=0.0017). The prevalence of AC joint CC increases with age and is associated with knee CC. A finding of AC joint CC should heighten suspicion of pseudogout or secondary osteoarthritis in appropriate clinical settings and, in a young patient, should alert the clinician to the possibility of an associated metabolic condition. PMID:23609408

  14. Does coronary calcium scoring with a SCORE better predict significant coronary artery stenosis than without? Correlation with computed tomography coronary angiography

    Energy Technology Data Exchange (ETDEWEB)

    Durhan, Gamze; Hazirolan, Tuncay; Karcaaltincaba, Musturay; Akata, Deniz [Hacettepe University Medical School, Department of Radiology, Ankara (Turkey); Sunman, Hamza; Aytemir, Kudret [Hacettepe University Medical School, Department of Cardiology, Ankara (Turkey); Karakaya, Jale; Karaagaoglu, Ergun [Hacettepe University, Department of Biostatistics, Ankara (Turkey)

    2014-12-03

    To determine effectiveness of coronary artery calcium score (CACS) alone and combined with Systematic Coronary Risk Evaluation (SCORE) in adult patients for significant coronary artery stenosis by using computed tomography coronary angiography (CTCA) as reference standard. Two thousand twenty-one patients with suspected coronary artery disease (CAD) underwent CACS test and CTCA. Patients were examined with dual-source CT and were grouped according to their age, gender, CACS, and estimated SCORE risk. Coronary plaque existence and degree of stenosis were assessed with CTCA. Sensitivity, specificity, and ROC curves were analyzed. CACS was the single independent variable in estimating relative risk of critical stenosis and had superior outcome when compared with SCORE risk in logistic regression and ROC curve. Area under the ROC curve was greatest in the interval between 50-59 years. When SCORE was combined with CACS in patients with zero CACS, percentage of significant stenosis increased from 1.4% to 7.0% in patients with high or very high SCORE risk, and decreased to 0.9 % in patients with low or moderate SCORE risk. CACS combination with SCORE risk predicts coronary artery stenosis. When CACS is zero, CTCA can be performed in patients with high or very high SCORE risk. (orig.)

  15. Improvement of desolvation and resilience of alginate binders for Si-based anodes in a lithium ion battery by calcium-mediated cross-linking.

    Science.gov (United States)

    Yoon, Jihee; Oh, Dongyeop X; Jo, Changshin; Lee, Jinwoo; Hwang, Dong Soo

    2014-12-14

    Si-based anodes in lithium ion batteries (LIBs) have exceptionally high theoretical capacity, but the use of a Si-based anode in LIBs is problematic because the charging-discharging process can fracture the Si particles. Alginate and its derivatives show promise as Si particle binders in the anode. We show that calcium-mediated "egg-box" electrostatic cross-linking of alginate improves toughness, resilience, electrolyte desolvation of the alginate binder as a Si-binder for LIBs. Consequently, the improved mechanical properties of the calcium alginate binder compared to the sodium alginate binder and other commercial binders extend the lifetime and increase the capacity of Si-based anodes in LIBs.

  16. Influence of Calcium Carbonate Fillers on the Properties of Recycled Poly(e-caprolactone Based Thermoplastic Polyurethane

    Directory of Open Access Journals (Sweden)

    Vitalija BETINGYTĖ

    2012-09-01

    Full Text Available In this work the effects of different crystallographic modifications of calcium carbonate (CaCO3 filler on the melt flow, mechanical properties, hydrolytic degradation, and shape memory behaviour of recycled low-temperature poly(e-caprolactone-based polyurethane (rTPU were evaluated. Composites were prepared by two-roll milling varying filler content from 2 wt % to 6 wt %. It was found that at temperature range from 20 °C to 50 °C CaCO3 fillers do not change Young’s modulus, they decrease tensile stress and deformation of rTPU, but improve its mechanical properties at elevated temperatures (up to 65 °C. rTPU melt flow index increases due to chain scission during the recycling and filler mixing with mill. Therefore, destruction temperature of rTPU is 20 °C lower than that of TPU. The CaCO3 does not change shape memory properties independently of filler type and transition from secondary shape to the primary shape at 70 °C temperature is completed within 17 s for both filled and unfilled rTPU. The investigation of hydrolytic degradation shows that CaCO3 only slightly increases degradation rate of rTPU.DOI: http://dx.doi.org/10.5755/j01.ms.18.3.2433

  17. Effect of curing time on microstructure and mechanical strength development of alkali activated binders based on vitreous calcium aluminosilicate (VCAS)

    Indian Academy of Sciences (India)

    M M Tashima; L Soriano; M V Borrachero; J Monzó; J Payá

    2013-04-01

    The aim of this paper is to study the influence of curing time on the microstructure and mechanical strength development of alkali activated binders based on vitreous calcium aluminosilicate (VCAS). Mechanical strength of alkali activated mortars cured at 65 °C was assessed for different curing times (4–168 h) using 10 molal NaOH solution as alkaline activator. Compressive strength values around 77MPa after three days of curing at 65 °C were obtained. 1.68MPa/h compressive strength gain rate was observed in the first 12 h, decreasing to 0.95MPa/h for the period of 12–72 h. The progress of geopolymeric reaction was monitored by means of TGA and, electrical conductivity and pH measurements in an aqueous suspension. Significant decrease in pH and electrical conductivity were observed in the 4–72 h period, demonstrating the geopolymerization process. Furthermore, SEM images showed an important amount of (N, C)ASH gel and low porosity of the developed matrix.

  18. Push-out bond strength of MTA HP, a new high-plasticity calcium silicate-based cement.

    Science.gov (United States)

    Silva, Emmanuel Jnl; Carvalho, Nancy Kudsi; Zanon, Mayara; Senna, Plínio Mendes; DE-Deus, Gustavo; Zuolo, Mário Luis; Zaia, Alexandre Augusto

    2016-06-14

    This study was designed to investigate the resistance to dislodgment provided by MTA HP, a new high-plasticity calcium silicate-based cement. Biodentine and White MTA Angelus were used as reference materials for comparison. Three discs 1 ± 0.1 mm thick were obtained from the middle third of the roots of 5 maxillary canines. Three 0.8-mm-wide holes were drilled on the axial surface of each root disc. Standardized irrigation was performed. Then the holes were dried with paper points and filled with one of the three tested cements. The filled dental slices were immersed in a phosphate-buffered saline (PBS) solution (pH 7.2) for 7 days before the push-out assessment. The Kruskal-Wallis test was applied to assess the effect of each endodontic cement on the push-out bond strength. Mann-Whitney with Bonferroni correction was used to isolate the differences. The alpha-type error was set at 0.05. All specimens had measurable push-out values and no premature failure occurred. There were significant differences among the materials (p <0.05). The Biodentine specimens had the highest push-out bond strength values (p < 0.05). MTA HP had significantly higher bond strength than White MTA (p < 0.05). MTA HP showed better push-out bond strength than its predecessor, White MTA; however, Biodentine had higher dislodgment resistance than both MTA formulations. PMID:27305515

  19. On-chip preparation of calcium alginate particles based on droplet templates formed by using a centrifugal microfluidic technique.

    Science.gov (United States)

    Liu, Mei; Sun, Xiao-Ting; Yang, Chun-Guang; Xu, Zhang-Run

    2016-03-15

    A novel chip-based approach for the fabrication of oblate spheriodal calcium alginate particles was developed by combining the droplet template method and the centrifugal microfluidic strategy. Circular chips with multiple radial channels were designed. Sodium alginate solutions in radial channels were flung into CaCl2 solutions in the form of droplets under centrifugal force, and the droplets transformed into particles through cross-linking reaction. The size and morphology of particles could be controlled by regulating the centrifugal force, the channel geometry and the distance between the channel outlet and the CaCl2 solution. The throughput of particle production was evidently enhanced by increasing the number of radial channels to 48 and 64. The coefficients of variation of particle sizes were in the range of 5.2-5.6%, which indicated the monodisperse particles could be prepared by using the present method. With the chip configuration readily modified, the same platform could be used to produce Janus particles. The Janus particles showed clear interfaces owing to the high flight speed and the rapid gelling process of the droplets. This method would be capable of generating particles with complicated morphology and multifunction from diverse polymeric materials.

  20. Apical and periapical tissues responses after root canal obturation with two calcium hydroxid based sealers in dog’s teeth

    Directory of Open Access Journals (Sweden)

    Maria Renata Giazzi NASSRI

    2008-08-01

    Full Text Available Introduction: At the ending of endodontic treatment, is very importantthat the choice of root canal’s sealer will be done by biologicalcompatibility criterial, which could promote less inflammation, turning quicker and more effective the healing process. Objective and material and methods: The aim of this study was to evaluate the apical and periapical tissues reactions in dog’s teeth, after pulpectomy and root canal’s cleaning and shaping, which limit was the fisiological barrier of delta apical, and filling with gutta-percha and two calcium hydroxide based endodontics sealers, Sealapex® and Apexit®, by those hystopatological events in observation periods of 7, 21 and 45 days,making a comparison of inflammatory reactions and reparacional evolution that both materials promoted. Past all periods, the dogs were killed and histological cuts of teeth were obtained. Results: Through qualitative-quantitative analysis, Sealapex showed inflammatory level among mild and moderate in all periods, having a great improvement in healing process at 45 days. There was a biggest dispersion of Apexitin periapical tissue, which caused an intense macrophage activity,raising inflammatory level in last period. Conclusion: Regardless of the sealer used, there were observed necrosis in a few of delta apical’s ramifications, being mostly in tooth filling by Apexit. In both ways,Sealapex showed best results than Apexit, about increased inflammatory reaction and healing process.

  1. Push-out bond strength of MTA HP, a new high-plasticity calcium silicate-based cement.

    Science.gov (United States)

    Silva, Emmanuel Jnl; Carvalho, Nancy Kudsi; Zanon, Mayara; Senna, Plínio Mendes; DE-Deus, Gustavo; Zuolo, Mário Luis; Zaia, Alexandre Augusto

    2016-06-14

    This study was designed to investigate the resistance to dislodgment provided by MTA HP, a new high-plasticity calcium silicate-based cement. Biodentine and White MTA Angelus were used as reference materials for comparison. Three discs 1 ± 0.1 mm thick were obtained from the middle third of the roots of 5 maxillary canines. Three 0.8-mm-wide holes were drilled on the axial surface of each root disc. Standardized irrigation was performed. Then the holes were dried with paper points and filled with one of the three tested cements. The filled dental slices were immersed in a phosphate-buffered saline (PBS) solution (pH 7.2) for 7 days before the push-out assessment. The Kruskal-Wallis test was applied to assess the effect of each endodontic cement on the push-out bond strength. Mann-Whitney with Bonferroni correction was used to isolate the differences. The alpha-type error was set at 0.05. All specimens had measurable push-out values and no premature failure occurred. There were significant differences among the materials (p Biodentine specimens had the highest push-out bond strength values (p Biodentine had higher dislodgment resistance than both MTA formulations.

  2. Hydration and strength development of binder based on high-calcium oil shale fly ash. Part 2: Influence of curing conditions on long-term stability

    Energy Technology Data Exchange (ETDEWEB)

    Freidin, C.

    1999-11-01

    The distinguishing feature of high-calcium oil shale fly ash (HCOSFA) used in experiments is the high amount of free CaO and SO{sub 3} in form of lime and anhydrite. Strength development as well as the microstructure and composition of the new formations of fly ash binder (FAB) based on HCOSFA and low-calcium coal fly ash after curing in different conditions and long-term exposure in various environments were studied. It was determined that moist air and water are the most favorable conditions for aging processes of FAB. In atmospheric air three stages in strength change of cured FAB are observed: increase of compressive strength over 1 month; sharp drop after 1 month up to the 3 to months; stabilization or slowdown of loss in strength after 3 to 6 months of exposure. The duration of the second and third stages depends on HCOSFA content and does not depend on curing conditions. One of the hydration products of FAB is ettringite. Its instability in air could be a reason for the decrease in strength of FAB and some disintegration of the hardened system. In the presence of low-calcium coal fly ash, additional amounts of stable calcium silicate hydrates are formed during FAB curing especially during steam curing. This has a positive effect on compressive strength and stability of FAB in atmospheric air.

  3. Association of Urinary Calcium Excretion with Serum Calcium and Vitamin D Levels

    OpenAIRE

    A Rathod; Bonny, O; Guessous, I; Suter, P M; Conen, D; Erne, P; Binet, I; Gabutti, L; Gallino, A; Muggli, F; Hayoz, D; Pechere-Bertschi, A; Paccaud, F.; Burnier, M.; Bochud, M

    2015-01-01

    BACKGROUND AND OBJECTIVES: Population-based data on urinary calcium excretion are scarce. The association of serum calcium and circulating levels of vitamin D [25(OH)D2 or D3] with urinary calcium excretion in men and women from a population-based study was explored. DESIGN, SETTINGS, PARTICIPANTS, & MEASUREMENTS: Multivariable linear regression was used to explore factors associated with square root-transformed 24-hour urinary calcium excretion (milligrams per 24 hours) taken as the dep...

  4. Generation of Quasi-Gaussian Pulses Based on Correlation Techniques

    Directory of Open Access Journals (Sweden)

    POHOATA, S.

    2012-02-01

    Full Text Available The Gaussian pulses have been mostly used within communications, where some applications can be emphasized: mobile telephony (GSM, where GMSK signals are used, as well as the UWB communications, where short-period pulses based on Gaussian waveform are generated. Since the Gaussian function signifies a theoretical concept, which cannot be accomplished from the physical point of view, this should be expressed by using various functions, able to determine physical implementations. New techniques of generating the Gaussian pulse responses of good precision are approached, proposed and researched in this paper. The second and third order derivatives with regard to the Gaussian pulse response are accurately generated. The third order derivates is composed of four individual rectangular pulses of fixed amplitudes, being easily to be generated by standard techniques. In order to generate pulses able to satisfy the spectral mask requirements, an adequate filter is necessary to be applied. This paper emphasizes a comparative analysis based on the relative error and the energy spectra of the proposed pulses.

  5. Interfacial Kinetics of High-Al-Containing Ultra-Lightweight Steels with Calcium Silicate-Based Molten Oxides at High Temperature

    Science.gov (United States)

    Kim, Gi Hyun; Sohn, Il

    2016-06-01

    The kinetics of the high-temperature reaction between high-Al- and -Mn-containing steels and synthesized molten calcium silicate-based fluxes from 1623 K to 1643 K (1350 °C to 1370 °C) was studied. Cylindrical steel rods were rotated in the molten fluxes for 300 to 1200 seconds at various temperatures below the melting point of the steels. The rods were connected to a rheometer, and the initial reaction rates were estimated from the torque variations. The dissolution of the steel into the molten slag was correlated to the variation in torque. The kinetics of the reaction between the rods and the slag estimated from the torque and subsequently from the viscosity were confirmed from the mass balance and from the variation in the chemical compositions of the rods and the molten slags, respectively. The liquid-phase mass transfer coefficient of Al2O3 was calculated to be 1.14 × 10-2 cm/s at 1623 K (1350 °C) and 1.52 × 10-2 cm/s at 1633 K (1360 °C). The kinetics calculated assuming liquid-phase mass transfer control was observed to be similar to the aforementioned kinetics determined from the dynamic viscosity variations. On the basis of dimensionless analysis of the Sherwood number (Sh = 0.05·Re0.65Sc0.31), liquid-phase mass transfer from the metal/flux interface was observed to be the rate-controlling step.

  6. Eigenvoice-based MAP adaptation within correlation subspace

    Institute of Scientific and Technical Information of China (English)

    LUO Jun; OU Zhi-jian; WANG Zuo-ying

    2006-01-01

    In recent years,the eigenvoice approach has proven to be an efficient method for rapid speaker adaptation,which directs the adaptation according to the analysis of full speaker vector space.In this article,we developed a new algorithm for eigenspace-based adaptation restricting eigenvoices in clustered subspaces, and maximum likelihood (ML) criterion was replaced with maximum aposteriori (MAP) criterion for better parameter estimation.Experiments show that even with one sentence adaptation data this algorithm would result in 6.45 % error ratio reduction relatively,which overcomes the instability of maximum likelihood linear regression (MLLR) with limited data and is much faster than traditional MAP method.This algorithm is not highly-dependent on subspace number of division,thus it proved to be a robust adaptation algorithm.

  7. In vitro biocompatibility and mechanical performance of titanium doped high calcium oxide metaphosphate-based glasses

    OpenAIRE

    Abou Neel, Ensanya A; Wojciech Chrzanowski; George Georgiou; Matthew J Dalby; Knowles, Jonathan C

    2010-01-01

    This study challenged to produce phosphate-based glasses (PBG) for the treatment of osseous defects. The glasses contained, among other components, 40 mol% CaO and 1-5 mol% TiO(2). The mechanical performance and in vitro biocompatibility using both human osteosarcoma and primary osteoblasts were carried out. Incorporation of TiO(2) into PBG had no significant effect on strength and modulus. These glasses encouraged attachment and maintained high viability of osteosarcoma cells similar to the ...

  8. A new phase-correlation-based Iris matching for degraded images

    OpenAIRE

    Krichen, Emine; Garcia-Salicetti, Sonia; Dorizzi, Bernadette

    2009-01-01

    In this paper, we present a new phase correlation-based iris matching approach in order to deal with degradations in iris images due to unconstrained acquisition procedures. Our matching system is a fusion of global and local Gabor phase correlation schemes. The main originality of our local approach is that we do not only consider the correlation peak amplitudes but also their locations in different regions of the images. Results on several degraded databases namely CASIA-BIOSECURE and Iris ...

  9. Joint transform correlator based on CIELAB model with encoding technique for color pattern recognition

    Science.gov (United States)

    Lin, Tiengsheng; Chen, Chulung; Liu, Chengyu; Chen, Yuming

    2010-10-01

    The CIELAB standard color vision model instead of the traditional RGB color model is utilized for polychromatic pattern recognition. The image encoding technique is introduced. The joint transform correlator is set to be the optical configuration. To achieve the distortion invariance in discrimination processes, we have used the minimum average correlation energy approach to yield sharp correlation peak. From the numerical results, it is found that the recognition ability based on CIELAB color specification system is accepted.

  10. The prevalence of chondrocalcinosis (CC) of the acromioclavicular (AC) joint on chest radiographs and correlation with calcium pyrophosphate dihydrate (CPPD) crystal deposition disease.

    Science.gov (United States)

    Parperis, Konstantinos; Carrera, Guillermo; Baynes, Keith; Mautz, Alan; Dubois, Melissa; Cerniglia, Ross; Ryan, Lawrence M

    2013-09-01

    Digital imaging combined with picture archiving and communication system (PACS) access allows detailed image retrieval and magnification. Calcium pyrophosphate dihydrate (CPPD) crystals preferentially deposit in fibrocartilages, the cartilage of the acromioclavicular (AC) joint being one such structure. We sought to determine if examination of the AC joints on magnified PACS imaging of chest films would be useful in identifying chondrocalcinosis (CC). Retrospective radiographic readings and chart reviews involving 1,920 patients aged 50 or more who had routine outpatient chest radiographs over a 4-month period were performed. Knee radiographs were available for comparison in 489 patients. Medical records were reviewed to abstract demographics, chest film reports, and diagnoses. AC joint CC was identified in 1.1 % (21/1,920) of consecutive chest films. Patients with AC joint CC were 75 years of age versus 65.4 in those without CC (p AC joint CC, and of these, five also had knee CC (83 %). Of the 483 without AC joint CC, 62 (12 %) had knee CC (p = 0.002). Patients with AC joint CC were more likely to have a recorded history of CPPD crystal deposition disease than those without AC joint CC (14 versus 1 %, p = 0.0017). The prevalence of AC joint CC increases with age and is associated with knee CC. A finding of AC joint CC should heighten suspicion of pseudogout or secondary osteoarthritis in appropriate clinical settings and, in a young patient, should alert the clinician to the possibility of an associated metabolic condition.

  11. A study of abnormal Calcium Phosphorus Product in Chronic Kidney Disease in Kerala population and its correlation with Acute Coronary Syndrome

    Directory of Open Access Journals (Sweden)

    Kartik Jadhav

    2016-07-01

    Full Text Available Objective: To determine the cutoff value for Calcium Phosphorus Product (CPP in Chronic Kidney Disease (CKD patients, above which there is a high risk of Acute Coronary Syndrome(ACS. Methods: Ninety five CKD patients on maintenance dialysis [2 to 3 sessions weekly] were followed up at AIMS, Kochi for a period of 2 years and any new onset acute coronary event during the following period were diagnosed and noted. All the relevant biochemical tests were performed including ECG and 2D Echocardiography. Standard statistical tests with multivariate regression analysis and ROC were performed to arrive at conclusion. Results: Out of 95 patients, 28 patients (29.5% had ACS, with majority number of patients above 50 years of age [27(96.4%]. Out of 95 patients 25(26.3% were females and 70(73.7% males. Out of 25 female patients 6(24% had ACS. Out of 70 male patients, 22(31.4% had ACS. The mean CPP was calculated for each patient and grouped into 4 groups [70]. Patients with CPP>70mg2/dl2 had highest incidence of ACS with 92.3% patients involved [Pvalue55mg2/dl2 had odds ratio of 18.214 after multivariate regression analysis. ROC curve for CPP showed a cutoff point of 51.4mg2/dl2 with sensitivity of 78.6% and specificity of 73.1% for predicting ACS. Conclusion: This study shows that the cutoff value for CPP above which ACS is common is 51.49mg2/dl2 for the local population, which is quite less than the recommended KDOQI guidelines. Therefore a stricter control among the local population is recommended.

  12. CaO insulator coatings on a vanadium-base alloy in liquid 2 at.% calcium-lithium

    Energy Technology Data Exchange (ETDEWEB)

    Park, J.H.; Kassner, T.F. [Argonne National Laboratory, IL (United States)

    1996-10-01

    The electrical resistance of CaO coatings produced on V-4%Cr-4%Ti and V-15%Cr-5%Ti by exposure of the alloy (round bottom samples 6-in. long by 0.25-in. dia.) to liquid lithium that contained 2 at.% dissolved calcium was measured as a function of time at temperatures between 300-464{degrees}C. The solute element, calcium in liquid lithium, reacted with the alloy substrate at these temperatures for 17 h to produce a calcium coating {approx}7-8 {mu}m thick. The calcium-coated vanadium alloy was oxidized to form a CaO coating. Resistance of the coating layer on V-15Cr-5Ti, measured in-situ in liquid lithium that contained 2 at.% calcium, was 1.0 x 10{sup 10} {Omega}-cm{sup 2} at 300{degrees}C and 400 h, and 0.9 x 10{sup 10} {Omega}-cm{sup 2} at 464{degrees}C and 300 h. Thermal cycling between 300 and 464{degrees}C changed the resistance of the coating layer, which followed insulator behavior. Examination of the specimen after cooling to room temperature revealed no cracks in the CaO coating. The coatings were evaluated by optical microscopy, scanning electron microscopy (SEM), electron dispersive spectroscopy (EDS), and X-ray analysis. Adhesion between CaO and vanadium alloys was enhanced as exposure time increased.

  13. Hydrogen ion and calcium releasing of mTA fillapex® and mTA-based formulations

    Directory of Open Access Journals (Sweden)

    Milton Carlos Kuga

    2011-07-01

    Full Text Available Introduction: MTA is composed of various metal oxides, calcium oxide and bismuth. It has good biological properties and is indicated in cases of endodontic complications. Several commercial formulations are available and further studies are necessary to evaluate these materials. Objective: To evaluate pH and calcium releasing of MTA Fillapex® compared with gray and white MTA. Material and methods: Gray and white MTA (Angelus and MTA Fillapex® (Angelus were manipulated and placed into polyethylene tubes and immersed in distilled water. The pH of these solutions was measured at 24 hours, 7 days and 14 days. Simultaneously, at these same aforementioned periods, these materials’ calcium releasing was quantified, through atomic absorption spectrophotometry. The results were submitted to ANOVA, with level of significance at 5%. Results: Concerning to pH, the materials present similar behaviors among each other at 24 hours (p > 0.05. At 7 and 14 days, MTA Fillapex® provided significantly lower pH values than the other materials (p < 0.05. Regarding to calcium releasing, at 24 hours and 7 days, MTA Fillapex® provided lower releasing than the other materials (p < 0.05. After 14 days, differences were found between MTA Fillapex® and gray MTA (p < 0.05. Conclusion: All materials showed alkaline pH and calcium releasing, with significantly lower values for MTA Fillapex® sealer.

  14. Human tooth germ stem cell response to calcium-silicate based endodontic cements

    Directory of Open Access Journals (Sweden)

    Esra Pamukcu Guven

    2013-07-01

    Full Text Available OBJECTIVE: The aim of this study was to compare the cytotoxic effects of endodontic cements on human tooth germ stem cells (hTGSCs. MTA Fillapex, a mineral trioxide aggregate (MTA-based, salicylate resin containing root canal sealer, was compared with iRoot SP, a bioceramic sealer, and AH Plus Jet, an epoxy resin-based root canal sealer. MATERIAL AND METHODS: To evaluate cytotoxicity, all materials were packed into Teflon rings (4 mmµ3 mm and co-cultured with hTGSCs with the aid of 24-well Transwell permeable supports, which had a pore size of 0.4 µm. Coverslips were coated with MTA Fillapex, iRoot SP and AH Plus Jet and each coverslip was placed onto the bottom of one well of a six-well plate for scanning electron microscopy (SEM analysis. Before the cytotoxicity and SEM analysis, all samples were stored at 37ºC and at 95% humidity and 5% CO2 for 24 hours to set. The cellular viability was analyzed using MTS test (3-(4,5-dimethyl-thiazol-2-yl-5-(3-carboxy-methoxy-phenyl-2-(4-sulfo-phenyl-2H-tetrazolium. The cytotoxic effects and SEM visualization of the tested materials were analyzed at 24-hour, 72-hour, one-week and two-week periods. RESULTS: On the 1st day, only MTA Fillapex caused cytotoxicity compared to negative control (NC group (p0.05. After 14 days of incubation with the test materials, MTA Fillapex exhibited significantly higher cytotoxicity compared with iRoot SP, AH Plus Jet and the NC group (P<0.008. In the SEM analysis, the highest levels of cell attachment were observed for iRoot SP and the control group. After 24 hours, MTA Fillapex reduced the number of cells attached to the surface. CONCLUSIONS: Within the limitations of this study, sealers exerted different cytotoxic effects on hTGSCs. Although all materials have exerted cellular toxicity, iRoot SP and AH Plus Jet may promote better attachment to hTGSCs.

  15. Influence of separate feeding of calcium on nutrient digestibility, energy utilisation and performance of young broilers fed pelleted wheat-based diets

    NARCIS (Netherlands)

    Abdollahi, M.R.; Dalen, van A.B.J.; Hendriks, W.H.; Ravindran, V.

    2015-01-01

    Six broiler starter diets, based on wheat and soybean meal, were formulated to contain 1.1 2.0, 4.0, 6.0, 8.0 and 10.0 g calcium (Ca)/kg. All diets were equivalent in respect of total and non-phytate phosphorus contents (5.4 and 3.0 g/kg, respectively). The influence of dietary treatments on the gro

  16. Fluorescence Based Characterization of Calcium Sensitizer Action on the Troponin Complex

    Energy Technology Data Exchange (ETDEWEB)

    Schlecht, William; Li, King-Lun; Hu, Dehong; Dong, Wen-Ji

    2016-02-01

    By examining the behavior of each Ca2+ -sensitizer on cTnC at different levels of reconstitution (cTnI-cTnC, full troponin, or full troponin in thin filament) the importance of these proteins on sensitizer efficacy was evaluated, lending insight into the mechanism of action behind each drug. A fluorescence based approach was used to monitor the opening and closing of cardiac troponin C's hydrophobic pocket in the presence and absence of four common Ca2+ -sensitizers: EMD 57033, levosimendan, bepridil and pimobendan. Ca2+ -titration experiments were employed to determine the effect on Ca2+- sensitivity and cooperativity of cTnC opening, while stopped flow experiments were used to investigate the impact on cTnC relaxation kinetics. This study shows EMD 57033 is unable to sensitize cTnC to Ca2+, and likely requires the presence of myosin to illicit a response. Levosimendan, bepridil, and pimobendan were all able to increase the sensitivity of cTnC for Ca2+ to varying degrees; levosimendan and pimobendan reduced the rate of cTnC closing, while bepridil increased this rate. Additionally the same experiments were run on thin filament samples containing cTnT (T204E), a known Ca2+- blunting phosphorylation mimic. Levosimendan, bepridil, and pimobendan were found to elevate the Ca2+-sensitivity of cTnT(T204E) containing thin filaments to within range of the wild type thin filaments.

  17. In vitro biocompatibility and mechanical performance of titanium doped high calcium oxide metaphosphate-based glasses.

    Science.gov (United States)

    Abou Neel, Ensanya A; Chrzanowski, Wojciech; Georgiou, George; Dalby, Matthew J; Knowles, Jonathan C

    2010-01-01

    This study challenged to produce phosphate-based glasses (PBG) for the treatment of osseous defects. The glasses contained, among other components, 40 mol% CaO and 1-5 mol% TiO(2). The mechanical performance and in vitro biocompatibility using both human osteosarcoma and primary osteoblasts were carried out. Incorporation of TiO(2) into PBG had no significant effect on strength and modulus. These glasses encouraged attachment and maintained high viability of osteosarcoma cells similar to the positive control surface. Cells grown directly (on glasses) or indirectly (in the presence of glass extracts) showed similar proliferation pattern to the positive control cells with no significant effect of TiO(2) detected. Increasing TiO(2) content, however, has a profound effect on cytoskeleton organization and spreading and maturation of primary osteoblasts. It is believed that TiO(2) might have acted as a chemical cue-modulating cells response, and hence the substrates supported maturation/mineralization of the primary osteoblasts. PMID:21350644

  18. Modified calcium oxide as stable solid base catalyst for Aldol condensation reaction

    Indian Academy of Sciences (India)

    Ying Tang; Jingfang Xu; Xuefan Gu

    2013-03-01

    A highly efficient and stable solid-base catalyst for Aldol condensation was prepared by modifying commercial CaO with benzyl bromide in a simple way. It was found that modified CaO can effectively catalyse the Aldol condensation of cyclohexanone and benzaldehyde, as well as various benzaldehydes, to produce 2-benzylidenecyclohexanone with a good selectivity and high yield. Higher yield of 95.8% was obtained over modified CaO after 3 h, which is short compared with the yield of 92.1% after 12 h over commercial CaO. The influence of several reaction parameters, such as temperature, catalyst loading, was investigated. The humidity test over modified CaO reveals that the basic centres of modified CaO are stable for CO2 and moisture. From the results of Fourier transform-infrared (FT-IR) and Thermogravity analysis (TG) characterization, the modifier was bonded on surface of CaO chemically and almost no Ca(OH)2 formed during the modification process. The type of aldehyde has great influence on the yield of aldol condensation.

  19. Effects of seawater alkalinity on calcium and acid-base regulation in juvenile European lobster (Homarus gammarus) during a moult cycle.

    Science.gov (United States)

    Middlemiss, Karen L; Urbina, Mauricio A; Wilson, Rod W

    2016-03-01

    Fluxes of NH4(+) (acid) and HCO3(-) (base), and whole body calcium content were measured in European lobster (Homarus gammarus) during intermoult (megalopae stage), and during the first 24h for postmoult juveniles under control (~2000 μeq/L) and low seawater alkalinity (~830 μeq/L). Immediately after moulting, animals lost 45% of the total body calcium via the shed exoskeleton (exuvia), and only 11% was retained in the uncalcified body. At 24h postmoult, exoskeleton calcium increased to ~46% of the intermoult stage. Ammonia excretion was not affected by seawater alkalinity. After moulting, bicarbonate excretion was immediately reversed from excretion to uptake (~4-6 fold higher rates than intermoult) over the whole 24h postmoult period, peaking at 3-6h. These data suggest that exoskeleton calcification is not completed by 24h postmoult. Low seawater alkalinity reduced postmoult bicarbonate uptake by 29% on average. Net acid-base flux (equivalent to net base uptake) followed the same pattern as HCO3(-) fluxes, and was 22% lower in low alkalinity seawater over the whole 24h postmoult period. The common occurrence of low alkalinity in intensive aquaculture systems may slow postmoult calcification in juvenile H. gammarus, increasing the risk of mortalities through cannibalism. PMID:26691956

  20. Effects of seawater alkalinity on calcium and acid-base regulation in juvenile European lobster (Homarus gammarus) during a moult cycle.

    Science.gov (United States)

    Middlemiss, Karen L; Urbina, Mauricio A; Wilson, Rod W

    2016-03-01

    Fluxes of NH4(+) (acid) and HCO3(-) (base), and whole body calcium content were measured in European lobster (Homarus gammarus) during intermoult (megalopae stage), and during the first 24h for postmoult juveniles under control (~2000 μeq/L) and low seawater alkalinity (~830 μeq/L). Immediately after moulting, animals lost 45% of the total body calcium via the shed exoskeleton (exuvia), and only 11% was retained in the uncalcified body. At 24h postmoult, exoskeleton calcium increased to ~46% of the intermoult stage. Ammonia excretion was not affected by seawater alkalinity. After moulting, bicarbonate excretion was immediately reversed from excretion to uptake (~4-6 fold higher rates than intermoult) over the whole 24h postmoult period, peaking at 3-6h. These data suggest that exoskeleton calcification is not completed by 24h postmoult. Low seawater alkalinity reduced postmoult bicarbonate uptake by 29% on average. Net acid-base flux (equivalent to net base uptake) followed the same pattern as HCO3(-) fluxes, and was 22% lower in low alkalinity seawater over the whole 24h postmoult period. The common occurrence of low alkalinity in intensive aquaculture systems may slow postmoult calcification in juvenile H. gammarus, increasing the risk of mortalities through cannibalism.

  1. THE CONSTRUCTIONS OF ALMOST BINARY SEQUENCE PAIRS WITH THREE-LEVEL CORRELATION BASED ON CYCLOTOMY

    Institute of Scientific and Technical Information of China (English)

    Peng Xiuping; Xu Chengqian

    2012-01-01

    In this paper,a new class of almost binary sequence pair with a single zero element is presented.The almost binary sequence pairs with three-level correlation are constructed based on cyclotomic numbers of order 2,4,and 6.Most of them have good correlation and balance property,whose maximum nontrivial correlation magnitudes are 2 and the difference between the numbers of occurrence of +1's and -1's are 0 or 1.In addition,the corresponding binary sequence pairs are investigated as well and we can also get some kinds of binary sequence pairs with optimum balance and good correlation.

  2. Calcium source (image)

    Science.gov (United States)

    Getting enough calcium to keep bones from thinning throughout a person's life may be made more difficult if that person has ... as a tendency toward kidney stones, for avoiding calcium-rich food sources. Calcium deficiency also effects the ...

  3. Calcium hydroxide poisoning

    Science.gov (United States)

    Hydrate - calcium; Lime milk; Slaked lime ... Calcium hydroxide ... These products contain calcium hydroxide: Cement Limewater Many industrial solvents and cleaners (hundreds to thousands of construction products, flooring strippers, brick cleaners, cement ...

  4. Calcium and bones (image)

    Science.gov (United States)

    Calcium is one of the most important minerals for the growth, maintenance, and reproduction of the human ... body, are continually being re-formed and incorporate calcium into their structure. Calcium is essential for the ...

  5. Coronary Calcium Scan

    Science.gov (United States)

    ... the NHLBI on Twitter. What Is a Coronary Calcium Scan? A coronary calcium scan is a test ... you have calcifications in your coronary arteries. Coronary Calcium Scan Figure A shows the position of the ...

  6. Calcium Pyrophosphate Deposition (CPPD)

    Science.gov (United States)

    ... Patient / Caregiver Diseases & Conditions Calcium Pyrophosphate Deposition (CPPD) Calcium Pyrophosphate Deposition (CPPD) Fast Facts The risk of ... young people, too. Proper diagnosis depends on detecting calcium pyrophosphate crystals in the fluid of an affected ...

  7. MIrExpress: A Database for Gene Coexpression Correlation in Immune Cells Based on Mutual Information and Pearson Correlation

    OpenAIRE

    Luman Wang; Qiaochu Mo; Jianxin Wang

    2015-01-01

    Most current gene coexpression databases support the analysis for linear correlation of gene pairs, but not nonlinear correlation of them, which hinders precisely evaluating the gene-gene coexpression strengths. Here, we report a new database, MIrExpress, which takes advantage of the information theory, as well as the Pearson linear correlation method, to measure the linear correlation, nonlinear correlation, and their hybrid of cell-specific gene coexpressions in immune cells. For a given ge...

  8. Scientific Opinion on the safety and efficacy of vitamin C (ascorbic acid, sodium ascorbate, calcium ascorbate, ascorbyl palmitate, sodium calcium ascorbyl phosphate and sodium ascorbyl phosphate) as a feed additive for all animal species based on a dossier submitted by DSM Nutritional Products Ltd

    OpenAIRE

    EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP)

    2013-01-01

    Vitamin C is essential for primates, guinea pigs and fish. Vitamin C, in the form of ascorbic acid and its calcium and sodium salts, ascorbyl palmitate, sodium calcium ascorbyl phosphate and sodium ascorbyl phosphate, is safe for all animal species. Setting a maximum content in feed and water for drinking is not considered necessary. Data on the vitamin C consumption of consumers are based on the levels of vitamin C in foodstuffs, including food of animal origin, produced in accordance with c...

  9. Characteristic Analysis on UAV-MIMO Channel Based on Normalized Correlation Matrix

    OpenAIRE

    Gao Xi jun; Chen Zi li; Hu Yong Jiang

    2014-01-01

    Based on the three-dimensional GBSBCM (geometrically based double bounce cylinder model) channel model of MIMO for unmanned aerial vehicle (UAV), the simple form of UAV space-time-frequency channel correlation function which includes the LOS, SPE, and DIF components is presented. By the methods of channel matrix decomposition and coefficient normalization, the analytic formula of UAV-MIMO normalized correlation matrix is deduced. This formula can be used directly to analyze the condition numb...

  10. Zirconium, calcium, and strontium contents in magnesium based biodegradable alloys modulate the efficiency of implant-induced osseointegration

    Directory of Open Access Journals (Sweden)

    Mushahary D

    2013-08-01

    Full Text Available Dolly Mushahary,1,2 Ragamouni Sravanthi,2 Yuncang Li,2 Mahesh J Kumar,1 Nemani Harishankar,4 Peter D Hodgson,1 Cuie Wen,3 Gopal Pande2 1Institute for Frontier Materials, Deakin University, Geelong, Australia; 2CSIR- Centre for Cellular and Molecular Biology, Hyderabad, India; 3Faculty of Engineering and Industrial Sciences, Swinburne University of Technology, Hawthorn, Australia; 4National Institute of Nutrition (ICMR, Tarnaka, Hyderabad, India Abstract: Development of new biodegradable implants and devices is necessary to meet the increasing needs of regenerative orthopedic procedures. An important consideration while formulating new implant materials is that they should physicochemically and biologically mimic bone-like properties. In earlier studies, we have developed and characterized magnesium based biodegradable alloys, in particular magnesium-zirconium (Mg-Zr alloys. Here we have reported the biological properties of four Mg-Zr alloys containing different quantities of strontium or calcium. The alloys were implanted in small cavities made in femur bones of New Zealand White rabbits, and the quantitative and qualitative assessments of newly induced bone tissue were carried out. A total of 30 experimental animals, three for each implant type, were studied, and bone induction was assessed by histological, immunohistochemical and radiological methods; cavities in the femurs with no implants and observed for the same period of time were kept as controls. Our results showed that Mg-Zr alloys containing appropriate quantities of strontium were more efficient in inducing good quality mineralized bone than other alloys. Our results have been discussed in the context of physicochemical and biological properties of the alloys, and they could be very useful in determining the nature of future generations of biodegradable orthopedic implants. Keywords: osteoblasts, bone mineralization, corrosion, osseointegration, surface energy, peri-implant

  11. Coverage of dynamic correlation effects by density functional theory functionals: Density-based analysis for neon

    Science.gov (United States)

    Jankowski, K.; Nowakowski, K.; Grabowski, I.; Wasilewski, J.

    2009-04-01

    The problem of linking the dynamic electron correlation effects defined in traditional ab initio methods [or wave function theories (WFTs)] with the structure of the individual density functional theory (DFT) exchange and correlation functionals has been analyzed for the Ne atom, for which nondynamic correlation effects play a negligible role. A density-based approach directly hinged on difference radial-density (DRD) distributions defined with respect the Hartree-Fock radial density has been employed for analyzing the impact of dynamic correlation effects on the density. Attention has been paid to the elimination of basis-set incompleteness errors. The DRD distributions calculated by several ab initio methods have been compared to their DFT counterparts generated for representatives of several generations of broadly used exchange-correlation functionals and for the recently developed orbital-dependent OEP2 exchange-correlation functional [Bartlett et al., J. Chem. Phys. 122, 034104 (2005)]. For the local, generalized-gradient, and hybrid functionals it has been found that the dynamic correlation effects are to a large extend accounted for by densities resulting from exchange-only calculations. Additional calculations with self-interaction corrected exchange potentials indicate that this finding cannot be explained as an artifact caused by the self-interaction error. It has been demonstrated that the VWN5 and LYP correlation functionals do not represent any substantial dynamical correlation effects on the electron density, whereas these effects are well represented by the orbital-dependent OEP2 correlation functional. Critical comparison of the present results with their counterparts reported in literature has been made. Some attention has been paid to demonstrating the differences between the energy- and density-based perspectives. They indicate the usefulness of density-based criteria for developing new exchange-correlation functionals.

  12. Using frame correlation algorithm in a duration distribution based hidden Markov model

    Institute of Scientific and Technical Information of China (English)

    王作英; 崔小东

    2000-01-01

    The assumption of frame independence is a widely known weakness of traditional hidden Markov model (HMM). In this paper, a frame correlation algorithm based on the duration distribution based hidden Markov model (DDBHMM) is proposed. In the algorithm, an AR model is used to depict the low pass effect of vocal tract from which stems the inertia leading to frame correlation. In the preliminary experiment of middle vocabulary speaker dependent isolated word recognition, our frame correlation algorithm outperforms the frame independent one. The average error reduction is about 20% .

  13. Correlation between vitamin D levels and muscle fatigue risk factors based on physical activity in healthy older adults

    Directory of Open Access Journals (Sweden)

    Al-Eisa ES

    2016-05-01

    Full Text Available Einas S Al-Eisa,1 Ahmad H Alghadir,1 Sami A Gabr1,2 1Rehabilitation Research Chair, College of Applied Medical Sciences, King Saud University, Riyadh, Kingdom of Saudi Arabia; 2Department of Anatomy, Faculty of Medicine, Mansoura University, Mansoura, Egypt Purpose: The purpose of this study was to investigate the relationship of serum vitamin D levels with physical activity, obesity, muscle fatigue biomarkers, and total antioxidant capacity (TAC in healthy older adults.Methods: A total of 85 healthy older subjects aged 64–96 years were recruited in this study. Based on estimated energy expenditure scores, the participants were classified into three groups: inactive (n=25, moderate (n=20, and physically active (n=35. Serum 25(OHD (25-hydroxy vitamin D levels, metabolic syndrome parameters, TAC activity, muscle fatigue biomarkers (Ca, creatine kinase, lactic acid dehydrogenase, troponin I, hydroxyproline, physical activity, body fatness, and fatigue score (visual analog scale were estimated using immunoassay techniques and prevalidated questionnaires, respectively.Results: Physical activity was estimated in 64.6% of the participants. Males showed higher physical activity (42.5% compared to females (26.25%. Compared to participants with lower activity, significant reduction in body mass index, waist circumference, hips, fasting blood sugar, triglycerides, total cholesterol, HDL-cholesterol, and LDL-cholesterol were observed in moderate and physically active participants. Also, significant increase in the levels of serum 25(OHD concentrations, calcium, and TAC activity along with reduction in the levels of muscle fatigue biomarkers: creatine kinase, lactic acid dehydrogenase, troponin I, hydroxyproline, and fatigue scores (visual analog scale were reported in physically active participants compared to those of lower physical activity. In all participants, serum 25(OHD concentrations correlated positively with Ca, TAC, physical activity scores

  14. CO{sub 2} capture efficiency and energy requirement analysis of power plant using modified calcium-based sorbent looping cycle

    Energy Technology Data Exchange (ETDEWEB)

    Li, Y.J.; Zhao, C.S.; Chen, H.C.; Ren, Q.Q.; Duan, L.B. [Southeast University, Nanjing (China). School of Energy & Environment

    2011-03-15

    This paper examines the average carbonation conversion, CO{sub 2} capture efficiency and energy requirement for post-combustion CO{sub 2} capture system during the modified calcium-based sorbent looping cycle. The limestone modified with acetic acid solution, i.e. calcium acetate is taken as an example of the modified calcium-based sorbents. The modified limestone exhibits much higher average carbonation conversion than the natural sorbent under the same condition. The CO{sub 2} capture efficiency increases with the sorbent flow ratios. Compared with the natural limestone, much less makeup mass flow of the recycled and the fresh sorbent is needed for the system when using the modified limestone at the same CO{sub 2} capture efficiency. Achieving 0.95 of CO{sub 2} capture efficiency without sulfation, 272 kJ/mol CO{sub 2} is required in the calciner for the natural limestone, whereas only 223 kJ/mol CO{sub 2} for the modified sorbent. The modified limestone possesses greater advantages in CO{sub 2} capture efficiency and energy consumption than the natural sorbent. When the sulfation and carbonation of the sorbents take place simultaneously, more energy is required. It is significantly necessary to remove SO{sub 2} from the flue gas before it enters the carbonator in order to reduce energy consumption in the calciner.

  15. Visualizing Presynaptic Calcium Dynamics and Vesicle Fusion with a Single Genetically Encoded Reporter at Individual Synapses.

    Science.gov (United States)

    Jackson, Rachel E; Burrone, Juan

    2016-01-01

    Synaptic transmission depends on the influx of calcium into the presynaptic compartment, which drives neurotransmitter release. Genetically encoded reporters are widely used tools to understand these processes, particularly pHluorin-based reporters that report vesicle exocytosis and endocytosis through pH dependent changes in fluorescence, and genetically encoded calcium indicators (GECIs) that exhibit changes in fluorescence upon binding to calcium. The recent expansion of the color palette of available indicators has made it possible to image multiple probes simultaneously within a cell. We have constructed a single molecule reporter capable of concurrent imaging of both presynaptic calcium influx and exocytosis, by fusion of sypHy, the vesicle associated protein synaptophysin containing a GFP-based pHluorin sensor, with the red-shifted GECI R-GECO1. Due to the fixed stoichiometry of the two probes, the ratio of the two responses can also be measured, providing an all optical correlate of the calcium dependence of release. Here, we have characterized stimulus-evoked sypHy-RGECO responses of hippocampal synapses in vitro, exploring the effects of different stimulus strengths and frequencies as well as variations in external calcium concentrations. By combining live sypHy-RGECO imaging with post hoc fixation and immunofluorescence, we have also investigated correlations between structural and functional properties of synapses. PMID:27507942

  16. Integration of gene expression and GWAS results supports involvement of calcium signaling in Schizophrenia.

    Science.gov (United States)

    Hertzberg, L; Katsel, P; Roussos, P; Haroutunian, V; Domany, E

    2015-05-01

    The number of Genome Wide Association Studies (GWAS) of schizophrenia is rapidly growing. However, the small effect of individual genes limits the number of reliably implicated genes, which are too few and too diverse to perform reliable pathway analysis; hence the biological roles of the genes implicated in schizophrenia are unclear. To overcome these limitations we combine GWAS with genome-wide expression data from human post-mortem brain samples of schizophrenia patients and controls, taking these steps: 1) Identify 36 GWAS-based genes which are expressed in our dataset. 2) Find a cluster of 19 genes with highly correlated expression. We show that this correlation pattern is robust and statistically significant. 3) GO-enrichment analysis of these 19 genes reveals significant enrichment of ion channels and calcium-related processes. This finding (based on analyzing a small number of coherently expressed genes) is validated and enhanced in two ways: First, the emergence of calcium channels and calcium signaling is corroborated by identifying proteins that interact with those encoded by the cluster of 19. Second, extend the 19 cluster genes into 1028 genes, whose expression is highly correlated with the cluster's average profile. When GO-enrichment analysis is performed on this extended set, many schizophrenia related pathways appear, with calcium-related processes enriched with high statistical significance. Our results give further, expression-based validation to GWAS results, support a central role of calcium-signaling in the pathogenesis of schizophrenia, and point to additional pathways potentially related to the disease.

  17. Ions Release and pH of Calcium Hydroxide-, Chlorhexidine- and Bioactive Glass-Based Endodontic Medicaments.

    Science.gov (United States)

    Carvalho, Ceci Nunes; Freire, Laila Gonzales; Carvalho, Alexandre Pinheiro Lima de; Duarte, Marco Antonio Húngaro; Bauer, José; Gavini, Giulio

    2016-01-01

    This study evaluated pH and release of calcium, sodium and phosphate ions from different medications in human dentin. Fifty premolars were prepared and randomly divided into groups: (CHX) - 2% chlorhexidine gel; (CHX + CH) - CHX + calcium hydroxide PA; (CH) - CH + propylene glycol 600; (NPBG) - experimental niobium phosphate bioactive glass + distilled water; (BG) - bioactive glass (Bio-Gran) + distilled water. The specimens were immersed in deionized water and the pH variations were measured. The quantification of ions in the solutions was made by inductively coupled plasma - atomic emission spectroscopy (ICP/AES) at 10 min, 24 h, 7, 14, 21 and 30 days. The results were analyzed by ANOVA and Tukey`s test, with a significance level of 5%. CH had the highest level of calcium ions release at 30 days, while CHX and BG released more sodium ions. BG, NPBG and CHX released a higher amount of phosphate ions. The pH of CH was significantly higher compared with the other groups. CH favored the greatest increase of pH and calcium ions release. The bioactive glasses released more sodium and phosphate ions and presented an alkaline pH immediately and after 30 days. PMID:27224568

  18. Phase synchronization based minimum spanning trees for analysis of financial time series with nonlinear correlations

    Science.gov (United States)

    Radhakrishnan, Srinivasan; Duvvuru, Arjun; Sultornsanee, Sivarit; Kamarthi, Sagar

    2016-02-01

    The cross correlation coefficient has been widely applied in financial time series analysis, in specific, for understanding chaotic behaviour in terms of stock price and index movements during crisis periods. To better understand time series correlation dynamics, the cross correlation matrices are represented as networks, in which a node stands for an individual time series and a link indicates cross correlation between a pair of nodes. These networks are converted into simpler trees using different schemes. In this context, Minimum Spanning Trees (MST) are the most favoured tree structures because of their ability to preserve all the nodes and thereby retain essential information imbued in the network. Although cross correlations underlying MSTs capture essential information, they do not faithfully capture dynamic behaviour embedded in the time series data of financial systems because cross correlation is a reliable measure only if the relationship between the time series is linear. To address the issue, this work investigates a new measure called phase synchronization (PS) for establishing correlations among different time series which relate to one another, linearly or nonlinearly. In this approach the strength of a link between a pair of time series (nodes) is determined by the level of phase synchronization between them. We compare the performance of phase synchronization based MST with cross correlation based MST along selected network measures across temporal frame that includes economically good and crisis periods. We observe agreement in the directionality of the results across these two methods. They show similar trends, upward or downward, when comparing selected network measures. Though both the methods give similar trends, the phase synchronization based MST is a more reliable representation of the dynamic behaviour of financial systems than the cross correlation based MST because of the former's ability to quantify nonlinear relationships among time

  19. New perspectives in face correlation: discrimination enhancement in face recognition based on iterative algorithm

    Science.gov (United States)

    Wang, Q.; Alfalou, A.; Brosseau, C.

    2016-04-01

    Here, we report a brief review on the recent developments of correlation algorithms. Several implementation schemes and specific applications proposed in recent years are also given to illustrate powerful applications of these methods. Following a discussion and comparison of the implementation of these schemes, we believe that all-numerical implementation is the most practical choice for application of the correlation method because the advantages of optical processing cannot compensate the technical and/or financial cost needed for an optical implementation platform. We also present a simple iterative algorithm to optimize the training images of composite correlation filters. By making use of three or four iterations, the peak-to-correlation energy (PCE) value of correlation plane can be significantly enhanced. A simulation test using the Pointing Head Pose Image Database (PHPID) illustrates the effectiveness of this statement. Our method can be applied in many composite filters based on linear composition of training images as an optimization means.

  20. MODIFICATION OF PRECIPITATED CALCIUM CARBONATE FILLER USING SODIUM SILICATE/ZINC CHLORIDE BASED MODIFIERS TO IMPROVE ACID-RESISTANCE AND USE OF THE MODIFIED FILLER IN PAPERMAKING

    Directory of Open Access Journals (Sweden)

    Jing Shen

    2009-11-01

    Full Text Available In order to improve the acid-resistant property of papermaking grade precipitated calcium carbonate filler and to obtain modified filler in powder form, sodium silicate/zinc chloride based modifiers were used in filler modification, and the use of modified filler in papermaking of deinked pulp derived from recycled newspaper was also preliminarily investigated. Under the preliminarily optimized experimental conditions, when sodium silicate, zinc chloride, sodium hexametaphosphate, and phosphoric acid with dosages of 10 wt%, 3 wt%, 1 wt% and 0.2 wt%, respectively, were used as modifiers, and when the temperature, aging time, and PCC concentration during the filler modification process was 70 oC, 7 h and 9.1 wt%, respectively, the acid-resistant property of filler was significantly improved after modification, as evaluated using alum consumption and pH methods. The use of modified precipitated calcium carbonate filler prepared under the optimized conditions provided considerably more brightness and light scattering improvement in comparison to unmodified filler, and filler modification was found to have only negligible influence on tensile and burst strength of the paper, air permeability of the paper, and retention performance of the filler. Surface analysis of the modified filler using XPS and SEM confirmed the occurring of surface encapsulation and modification of precipitated calcium carbonate filler when the relevant modifiers were used in filler modification. The encapsulating effect of modifiers on filler was thought to be favorable to improvement in acid-resistant property, and optical properties of the filled paper.

  1. Calcium and Vitamin D

    Science.gov (United States)

    ... Home › Patients › Treatment › Calcium/Vitamin D Calcium/Vitamin D Getting enough calcium and vitamin D is essential ... counter medications and calcium supplements. What is Vitamin D and What Does it Do? Vitamin D plays ...

  2. Correlation between self-reported and clinically based diagnoses of bruxism in temporomandibular disorders patients

    NARCIS (Netherlands)

    D.A. Paesani; F. Lobbezoo; C. Gelos; L. Guarda-Nardini; J. Ahlberg; D. Manfredini

    2013-01-01

    The present investigation was performed in a population of patients with temporomandibular disorders (TMD), and it was designed to assess the correlation between self-reported questionnaire-based bruxism diagnosis and a diagnosis based on history taking plus clinical examination. One-hundred-fifty-n

  3. Phase-shifting technique applied to circular harmonic-based joint transform correlator

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The phase-shifting technique is applied to the circular harmonic expansion-based joint transform correlator. Computer simulation has shown that the light efficiency and the discrimination capability are greatly enhanced, and the full rotation invariance is preserved after the phase-shifting technique has been used. A rotation-invariant optical pattern recognition with high discrimination capability and high light efficiency is obtained. The influence of the additive noise on the performance of the correlator is also investigated. However, the anti-noise capability of this kind of correlator still needs improving.

  4. Diagnosis of soft faults in analog integrated circuits based on fractional correlation

    Institute of Scientific and Technical Information of China (English)

    Deng Yong; Shi Yibing; Zhang Wei

    2012-01-01

    Aiming at the problem of diagnosing soft faults in analog integrated circuits,an approach based on fractional correlation is proposed.First,the Volterra series of the circuit under test (CUT) decomposed by the fractional wavelet packet are used to calculate the fractional correlation functions.Then,the calculated fractional correlation functions are used to form the fault signatures of the CUT.By comparing the fault signatures,the different soft faulty conditions of the CUT are identified and the faults are located.Simulations of benchmark circuits illustrate the proposed method and validate its effectiveness in diagnosing soft faults in analog integrated circuits.

  5. Radiocalcium Measurement of Bone Turnover in Disorders of Calcium Metabolism Using a Model Based on an Expanding Pool

    International Nuclear Information System (INIS)

    To determine bone mineralization rate the patient eats a constant daily diet for the duration of the study. 10 μCi of 47CaCl2 are injected intravenously on day one of the investigation. Blood samples are taken at 5, 10, 20, 40 and 90 minutes, 3, 5, 9 and 22 hours and 2, 3, 4, 5 and 7 days. 47Ca radioactivity is measured in all the plasma and daily faecal and urine samples. Bone mineralization is determined using a model based on the concept that the exchangeable calcium pool is continuously expanding according to a power function and that activity is lost from the pool into faeces, urine and bone (by mineralization) in direct proportion to the specific activity of the plasma (S*). The power function can be determined graphically from a log/log plot of the S* data over the first 15 hours. Extrapolation of this line to day 7 permits calculation of the pool size at that time (reciprocal of the calculated Sp*7) and the product of the calculated pool and actual S7* yields the amount of activity in the pool at day 7. This is deducted from the activity retained at day 7 to give the activity attributable to bone mineralization which is then divided by the integrated S* over the 7 days to yield the bone mineralization rate. Usually the whole calculation is performed by curve fitting the data points with the aid of a computer. In contrast to previously published methods for the determination of the bone mineralization rates the results presented are independent of the portion of the S* curve that is analysed and thus bone mineralization can be determined in 7 days, previous methods requiring 14 days or more. The normal mineralization rate is 4-6 mg Ca/kg per day. High values of bone mineralization are found in groups of patients with Paget' s disease, osteomalacia, hyperthyroidism, hyperparathyroidism and renal osteodystrophy. Low values for bone mineralization have been found in some patients with crush fracture osteoporosis and in hypoparathyroidism. Changes in bone

  6. Improving signal-to-noise ratio performance of compressive imaging based on spatial correlation

    Science.gov (United States)

    Mao, Tianyi; Chen, Qian; He, Weiji; Zou, Yunhao; Dai, Huidong; Gu, Guohua

    2016-07-01

    In this paper, compressive imaging based on spatial correlation (CISC), which uses second-order correlation with the measurement matrix, is introduced to improve the signal-to-noise ratio performance of compressive imaging (CI). Numerical simulations and experiments are performed as well. Referred to the results, it can be seen that CISC performs much better than CI in three common noise environments. This provides the great opportunity to pave the way for real applications.

  7. A Camera Nodes Correlation Model Based on 3D Sensing in Wireless Multimedia Sensor Networks

    OpenAIRE

    Chong Han; Lijuan Sun; Fu Xiao; Jian Guo; Ruchuan Wang

    2012-01-01

    In wireless multimedia sensor networks, multiple camera sensor nodes generally are used for gaining enhanced observations of a certain area of interest. This brings on the visual information retrieved from adjacent camera nodes usually exhibits high levels of correlation. In this paper, first, based on the analysis of 3D directional sensing model of camera sensor nodes, a correlation model is proposed by measuring the intersection area of multiple camera nodes’ field of views. In this model, ...

  8. Deterministic quantum key distribution based on Gaussian-modulated EPR correlations

    Institute of Scientific and Technical Information of China (English)

    He Guang-Qiang; Zeng Gui-Hua

    2006-01-01

    This paper proposes a deterministic quantum key distribution scheme based on Gaussian-modulated continuous variable EPR correlations. This scheme can implement fast and efficient key distribution. The security is guaranteed by continuous variable EPR entanglement correlations produced by nondegenerate optical parametric amplifier. For general beam splitter eavesdropping strategy, the secret information rate△I = I(α,β) - I(α,ε) is calculated in view of Shannon information theory. Finally the security analysis is presented.

  9. Gas monitoring data anomaly identification based on spatio-temporal correlativity analysis

    Institute of Scientific and Technical Information of China (English)

    Shi-song ZHU; Yun-jia WANG; Lian-jiang WEI

    2013-01-01

    Based on spatio-temporal correlativity analysis method,the automatic identification techniques for data anomaly monitoring of coal mining working face gas are presented.The asynchronous correlative characteristics of gas migration in working face airflow direction are qualitatively analyzed.The calculation method of asynchronous correlation delay step and the prediction and inversion formulas of gas concentration changing with time and space after gas emission in the air return roadway are provided.By calculating one hundred and fifty groups of gas sensors data series from a coal mine which have the theoretical correlativity,the correlative coefficient values range of eight kinds of data anomaly is obtained.Then the gas monitoring data anomaly identification algorithm based on spatio-temporal correlativity analysis is accordingly presented.In order to improve the efficiency of analysis,the gas sensors code rules which can express the spatial topological relations are suggested.The experiments indicate that methods presented in this article can effectively compensate the defects of methods based on a single gas sensor monitoring data.

  10. Synthesis and structural characterization of a calcium coordination polymer based on a 3-bridging tetradentate binding mode of glycine

    Indian Academy of Sciences (India)

    Subramanian Natarajan; Bikshandarkoil R Srinivasan; J Kalyana Sundar; K Ravikumar; R V Krishnakumar; J Suresh

    2012-07-01

    A new coordination polymer namely [[Ca6(H-gly)12(H2O)18]Cl12·6H2O] (1) (H-gly = glycine) has been isolated from the calcium chloride-glycine-water system and structurally characterized. Each Ca(II) in 1 is eight-coordinated and is bonded to eight oxygen atoms three of which are from terminal water molecules and five oxygen atoms from four symmetry related zwitterionic glycine ligands. The H-gly ligands exhibit two different binding modes viz. a monodentate carboxylate ligation and a 3-tetradentate bridging carboxylate binding mode, which results in the formation of a one-dimensional coordination polymer. In the infinite chain the Ca(II) atoms are organized in a zigzag fashion. A comparative study reveals a rich and diverse structural chemistry of calcium halide-glycine compounds.

  11. In vitro analysis of the pH alteration of the dentine after using different calcium hydroxide- based pastes

    Directory of Open Access Journals (Sweden)

    Cláudio Maniglia-Ferreira

    2013-06-01

    Full Text Available Introduction and Objective: To analyze the pH increase at the external root surface after the use of different calcium hydroxide pastes (Calen, calcium hydroxide associated with 2% chlorhexidine gel, calcium hydroxide associated with saline with and without EDTA as chelating agent before the topical application of the intracanal medication. Material and methods: One-hundred single-rooted extracted teeth were cleaned and shaped. They were randomly divided into six experimental groups (n = 15 and one control group (n = 10, according to the medication to be used. The teeth were kept immersed in saline solution and the pH measurements were weekly verified with the aid of a pH meter. Results: It was verified the pH increasing at the first week in almost all groups. Only the groups in which Ca(OH2 was associated with 2% chlorhexidine gel exhibited a significant evolution in the pH increasing over time (p = 0.0116. The use of EDTA did not result in higher pH values (p = 0.2278. Conclusion: i the pH increased in all associations used; ii 2% chlorhexidine gel allowed the gradual pH increasing over time; iii the smear layer removal did not influence on the pH increasing.

  12. Adaptive endpoint detection of seismic signal based on auto-correlated function

    International Nuclear Information System (INIS)

    There are certain shortcomings for the endpoint detection by time-waveform envelope and/or by checking the travel table (both labelled as the artificial detection method). Based on the analysis of the auto-correlation function, the notion of the distance between auto-correlation functions was quoted, and the characterizations of the noise and the signal with noise were discussed by using the distance. Then, the method of auto-adaptable endpoint detection of seismic signal based on auto-correlated similarity was summed up. The steps of implementation and determining of the thresholds were presented in detail. The experimental results that were compared with the methods based on artificial detecting show that this method has higher sensitivity even in a low SNR circumstance

  13. Recommended System for Neighborhoo-Based Collaborative Filtering Algorithm Using Pearson Correlation

    OpenAIRE

    Thomurthy, Murali Mohan; KOICHI Harada; Balakrishna. ANNEPU

    2013-01-01

    Memory based collaborative filtering technique is successful approach to build a recommender system uses the known preferences of a group of users to make predictions of the unknown preferences for other users. In order to make such predictions the Pearson correlation coefficient is considered for user similarity. User-based Collaborative Filtering is efficient when compared to k-Nearest Neighbor algorithm (k-NN) and Item-based collaborative filtering algorithms from the experiment results. I...

  14. Gating based on internal/external signals with dynamic correlation updates

    Science.gov (United States)

    Wu, Huanmei; Zhao, Qingya; Berbeco, Ross I.; Nishioka, Seiko; Shirato, Hiroki; Jiang, Steve B.

    2008-12-01

    Precise localization of mobile tumor positions in real time is critical to the success of gated radiotherapy. Tumor positions are usually derived from either internal or external surrogates. Fluoroscopic gating based on internal surrogates, such as implanted fiducial markers, is accurate however requiring a large amount of imaging dose. Gating based on external surrogates, such as patient abdominal surface motion, is non-invasive however less accurate due to the uncertainty in the correlation between tumor location and external surrogates. To address these complications, we propose to investigate an approach based on hybrid gating with dynamic internal/external correlation updates. In this approach, the external signal is acquired at high frequency (such as 30 Hz) while the internal signal is sparsely acquired (such as 0.5 Hz or less). The internal signal is used to validate and update the internal/external correlation during treatment. Tumor positions are derived from the external signal based on the newly updated correlation. Two dynamic correlation updating algorithms are introduced. One is based on the motion amplitude and the other is based on the motion phase. Nine patients with synchronized internal/external motion signals are simulated retrospectively to evaluate the effectiveness of hybrid gating. The influences of different clinical conditions on hybrid gating, such as the size of gating windows, the optimal timing for internal signal acquisition and the acquisition frequency are investigated. The results demonstrate that dynamically updating the internal/external correlation in or around the gating window will reduce false positive with relatively diminished treatment efficiency. This improvement will benefit patients with mobile tumors, especially greater for early stage lung cancers, for which the tumors are less attached or freely floating in the lung.

  15. A first-principles-based correlation functional for harmonious connection of short-range correlation and long-range dispersion

    CERN Document Server

    Modrzejewski, Marcin; Rajchel, Łukasz; Szczęśniak, Małgorzata M; Chałasiński, Grzegorz

    2014-01-01

    We present a physically motivated correlation functional belonging to the meta-generalized gradient approximation (meta-GGA) rung, which can be supplemented with long-range dispersion corrections without introducing double-counting of correlation contributions. The functional is derived by the method of constraint satisfaction, starting from an analytical expression for a real-space spin-resolved correlation hole. The model contains a position-dependent function that controls the range of the interelectronic correlations described by the semilocal functional. With minimal empiricism, this function may be adjusted so that the correlation model blends with a specific dispersion correction describing long-range contributions. For a preliminary assessment, our functional has been combined with the DFT-D3 dispersion correction and full Hartree-Fock (HF)-like exchange. Despite the HF-exchange approximation, its predictions compare favorably with reference interaction energies in an extensive set of non-covalently b...

  16. Formulation, caractérisation et mise en oeuvre de barrières perméables réactives à base de phosphate de calcium, Utilisation pour la fixation de polluants

    OpenAIRE

    Raii, Mohamed

    2012-01-01

    The main purpose of this thesis was the formulation of stable blends based on synthesized hydroxyapatite-gel (Ca-HAGel). The rheological behavior of water−calcium sulfates and hydroxyapatite−calcium sulfates blends was considered in this study. The results show that all blends and formulations exhibit a shear-thinning effect and thixotropic behavior. The ζ potential was used in this study to understand the interaction between particles and its effect on the global behavior of the blends. Fixa...

  17. Surface characterization and corrosion behavior of calcium phosphate-base composite layer on titanium and its alloys via plasma electrolytic oxidation: A review paper.

    Science.gov (United States)

    Rafieerad, A R; Ashra, M R; Mahmoodian, R; Bushroa, A R

    2015-12-01

    In recent years, calcium phosphate-base composites, such as hydroxyapatite (HA) and carbonate apatite (CA) have been considered desirable and biocompatible coating layers in clinical and biomedical applications such as implants because of the high resistance of the composites. This review focuses on the effects of voltage, time and electrolytes on a calcium phosphate-base composite layer in case of pure titanium and other biomedical grade titanium alloys via the plasma electrolytic oxidation (PEO) method. Remarkably, these parameters changed the structure, morphology, pH, thickness and crystallinity of the obtained coating for various engineering and biomedical applications. Hence, the structured layer caused improvement of the biocompatibility, corrosion resistance and assignment of extra benefits for Osseo integration. The fabricated layer with a thickness range of 10 to 20 μm was evaluated for physical, chemical, mechanical and tribological characteristics via XRD, FESEM, EDS, EIS and corrosion analysis respectively, to determine the effects of the applied parameters and various electrolytes on morphology and phase transition. Moreover, it was observed that during PEO, the concentration of calcium, phosphor and titanium shifts upward, which leads to an enhanced bioactivity by altering the thickness. The results confirm that the crystallinity, thickness and contents of composite layer can be changed by applying thermal treatments. The corrosion behavior was investigated via the potentiodynamic polarization test in a body-simulated environment. Here, the optimum corrosion resistance was obtained for the coating process condition at 500 V for 15 min in Ringer solution. This review has been summarized, aiming at the further development of PEO by producing more adequate titanium-base implants along with desired mechanical and biomedical features.

  18. Robust and discriminating method for face recognition based on correlation technique and independent component analysis model.

    Science.gov (United States)

    Alfalou, A; Brosseau, C

    2011-03-01

    We demonstrate a novel technique for face recognition. Our approach relies on the performances of a strongly discriminating optical correlation method along with the robustness of the independent component analysis (ICA) model. Simulations were performed to illustrate how this algorithm can identify a face with images from the Pointing Head Pose Image Database. While maintaining algorithmic simplicity, this approach based on ICA representation significantly increases the true recognition rate compared to that obtained using our previously developed all-numerical ICA identity recognition method and another method based on optical correlation and a standard composite filter. PMID:21368935

  19. Simple and easy estimation of network properties based on linear correlation analysis

    Directory of Open Access Journals (Sweden)

    Yanhong Qi

    2015-12-01

    Full Text Available An ecological network can be constructed by calculating the sampling data of taxon by sample type. A statistically significant Pearson linear correlation means an indirect or direct linear interaction between two taxa, and a statistically significant partial (net, or pure correlation based on Pearson linear correlation means a candidate direct linear interaction between two taxa. In many cases, statistically significant partial correlations are not available, or we only need to estimate some of network properties. Based on sampling data of arthropods in different countries and periods, in present study I proved that the number of candidate direct linear interactions (y increases with the number of indirect + direct linear interactions (x calculated by Pearson linear correlation (y=-0.2757+0.5343x, r2=0.859, p<0.00001, and the former is approximately half of the later. The proportion of candidate direct interactions in possible maximum interactions (y percent is approximately two-thirds of mean Pearson linear correlation (x (y=1.9060+64.6084x, r2=0.339, p=0.023. These conclusions are expected to provide simple and easy quantities to estimate some of network properties.

  20. Estimation and Prediction of the Condition of the Vehicle Engine Based on the Correlation Dimension

    Institute of Scientific and Technical Information of China (English)

    LiuChun; ZhangLaibin; WangZhaohui

    2004-01-01

    This paper applies the fractal dimension as a characteristic to describe the engine's operating condition and its developmental trend. A correlation dimension is one of the quantities that are usually used to characterize a strange attractor. With the operation of the phase space reconstruction, respective correlation dimensions of a series of vibration signals obtained under different conditions are calculated to find the intrinsic relationship between the indicator and the operating condition. The experiment result shows that the correlation dimension is sensitive to the condition evolution and convenient for the identification of abnormal operational states. In advanced prognostic algorithm based on the BP neural network is then applied on the correlation dimensions to predict the short-term running conditions in order to avoid severe faults and realize in-time maintenance. Experimental results are presented to illustrate the proposed methodology.

  1. Initial estimation of hydrate formation temperature of sweet natural gases based on new empirical correlation

    Institute of Scientific and Technical Information of China (English)

    Mohammad Mahdi Ghiasi

    2012-01-01

    Production,processing and transportation of natural gases can be significantly affected by clathrate hydrates.Knowing the gas analysis is crucial to predict the right conditions for hydrate formation.Nevertheless,Katz gas gravity method can be used for initial estimation of hydrate formation temperature (HFT) under the circumstances of indeterminate gas composition.So far several correlations have been proposed for gas gravity method,in which the most accurate and reliable one has belonged to Bahadori and Vuthaluru.The main objective of this study is to present a simple and yet accurate correlation for fast prediction of sweet natural gases HFT based on the fit to Katz gravity chart.By reviewing the error analysis results,one can discover that the new proposed correlation has the best estimation capability among the widely accepted existing correlations within the investigated range.

  2. A NEW SYSTEM DYNAMIC EXTREMUM SELF-SEARCHING METHOD BASED ON CORRELATION ANALYSIS

    Institute of Scientific and Technical Information of China (English)

    李嘉; 刘文江; 胡军; 袁廷奇

    2003-01-01

    Objective To propose a new dynamic extremum self-searching method, which can be used in industrial processes extremum optimum control systems, to overcome the disadvantages of traditional method. Methods This algorithm is based on correlation analysis. A pseudo-random binary signal m-sequence u(t) is added as probe signal in system input, construct cross-correlation function between system input and output, the next step hunting direction is judged by the differential sign. Results Compared with traditional algorithm such as step forward hunting method, the iterative efficient, hunting precision and anti-interference ability of the correlation analysis method is obvious over the traditional algorithm. The computer simulation experimental given illustrate these viewpoints. Conclusion The correlation analysis method can settle the optimum state point of device operating process. It has the advantage of easy condition , simple calculate process.

  3. Silicon, iron and titanium doped calcium phosphate-based glass reinforced biodegradable polyester composites as bone analogous materials

    Science.gov (United States)

    Shah Mohammadi, Maziar

    Bone defects resulting from disease or traumatic injury is a major health care problem worldwide. Tissue engineering offers an alternative approach to repair and regenerate bone through the use of a cell-scaffold construct. The scaffold should be biodegradable, biocompatible, porous with an open pore structure, and should be able to withstand the applied forces. Phosphate-based glasses (PGs) may be used as reinforcing agents in degradable composites since their degradation can be predicted and controlled through their chemistry. This doctoral dissertation describes the development and evaluation of PGs reinforced biodegradable polyesters for intended applications in bone augmentation and regeneration. This research was divided into three main objectives: 1) Investigating the composition dependent properties of novel PG formulations by doping a sodium-free calcium phosphate-based glass with SiO2, Fe2O3, and TiO2. Accordingly, (50P2 O5-40CaO- xSiO2-(10-x)Fe2O3, where x = 10, 5 and 0 mol.%) and (50P2O5-40CaO-xSiO 2-(10-x)TiO2 where x = 10, 7, 5, 3 and 0 mol.%) formulations were developed and characterised. SiO2 incorporation led to increased solubility, ion release, pH reduction, as well as hydrophilicity, surface energy, and surface polarity. In contrast, doping with Fe2O 3 or TiO2 resulted in more durable glasses, and improved cell attachment and viability. It was hypothesised that the presence of SiO 2 in the TiO2-doped formulations could up-regulate the ionic release from the PG leading to higher alkaline phosphatase activity of MC3T3-E1 cells. 2) Incorporating Si, Fe, and Ti doped PGs as fillers, either as particulates (PGPs) or fibres (PGFs), into biodegradable polyesters (polycaprolactone (PCL) and semi-crystalline and amorphous poly(lactic acid) (PLA and PDLLA)) with the aim of developing degradable bone analogous composites. It was found that PG composition and geometry dictated the weight loss, ionic release, and mechanical properties of the composites. It

  4. The influence of base rates on correlations: An evaluation of proposed alternative effect sizes with real-world data.

    Science.gov (United States)

    Babchishin, Kelly M; Helmus, Leslie-Maaike

    2016-09-01

    Correlations are the simplest and most commonly understood effect size statistic in psychology. The purpose of the current paper was to use a large sample of real-world data (109 correlations with 60,415 participants) to illustrate the base rate dependence of correlations when applied to dichotomous or ordinal data. Specifically, we examined the influence of the base rate on different effect size metrics. Correlations decreased when the dichotomous variable did not have a 50 % base rate. The higher the deviation from a 50 % base rate, the smaller the observed Pearson's point-biserial and Kendall's tau correlation coefficients. In contrast, the relationship between base rate deviations and the more commonly proposed alternatives (i.e., polychoric correlation coefficients, AUCs, Pearson/Thorndike adjusted correlations, and Cohen's d) were less remarkable, with AUCs being most robust to attenuation due to base rates. In other words, the base rate makes a marked difference in the magnitude of the correlation. As such, when using dichotomous data, the correlation may be more sensitive to base rates than is optimal for the researcher's goals. Given the magnitude of the association between the base rate and point-biserial correlations (r = -.81) and Kendall's tau (r = -.80), we recommend that AUCs, Pearson/Thorndike adjusted correlations, Cohen's d, or polychoric correlations should be considered as alternate effect size statistics in many contexts. PMID:26182856

  5. The influence of base rates on correlations: An evaluation of proposed alternative effect sizes with real-world data.

    Science.gov (United States)

    Babchishin, Kelly M; Helmus, Leslie-Maaike

    2016-09-01

    Correlations are the simplest and most commonly understood effect size statistic in psychology. The purpose of the current paper was to use a large sample of real-world data (109 correlations with 60,415 participants) to illustrate the base rate dependence of correlations when applied to dichotomous or ordinal data. Specifically, we examined the influence of the base rate on different effect size metrics. Correlations decreased when the dichotomous variable did not have a 50 % base rate. The higher the deviation from a 50 % base rate, the smaller the observed Pearson's point-biserial and Kendall's tau correlation coefficients. In contrast, the relationship between base rate deviations and the more commonly proposed alternatives (i.e., polychoric correlation coefficients, AUCs, Pearson/Thorndike adjusted correlations, and Cohen's d) were less remarkable, with AUCs being most robust to attenuation due to base rates. In other words, the base rate makes a marked difference in the magnitude of the correlation. As such, when using dichotomous data, the correlation may be more sensitive to base rates than is optimal for the researcher's goals. Given the magnitude of the association between the base rate and point-biserial correlations (r = -.81) and Kendall's tau (r = -.80), we recommend that AUCs, Pearson/Thorndike adjusted correlations, Cohen's d, or polychoric correlations should be considered as alternate effect size statistics in many contexts.

  6. Correlation of self-assessment with attendance in an evidence-based medicine course.

    Science.gov (United States)

    Ramirez, Beatriz U

    2015-12-01

    In previous studies, correlations between attendance and grades in lectures have given variable results and, when statistically significant, the correlation has been weak. In some studies, a sex effect has been reported. Lectures are a teacher-centered learning activity. Therefore, it appeared interesting to evaluate if a stronger correlation between attendance and grades would occur in a face-to-face "evidence-based medicine" course with few lectures and more time dedicated to active learning methods. Small-group work and peer learning were used to foster deep learning and to engage students in their own learning process. Most of the time, students worked in small groups solving contextualized problems and critically analyzing the quality of published medical literature. Peer learning was also developed in collaborative evaluations, and constant feedback was provided. Therefore, it was hypothesized that high attenders would develop a higher self-perception of learning and obtain higher marks than low attenders. Student self-perceptions of their capacity to apply evidence-based medicine were measured by the application of an online self-assessment survey, and objective learning was measured as the grades obtained in a final accumulative individual test. It was found that male students obtained higher grades and were more confident in their achievements than their female peers, despite male and female student attendance being similar. In addition, attendance was correlated with the perceived capacity to apply evidence-based medicine only in male students and was not correlated with academic outcome.

  7. Reliability sensitivity-based correlation coefficient calculation in structural reliability analysis

    Science.gov (United States)

    Yang, Zhou; Zhang, Yimin; Zhang, Xufang; Huang, Xianzhen

    2012-05-01

    The correlation coefficients of random variables of mechanical structures are generally chosen with experience or even ignored, which cannot actually reflect the effects of parameter uncertainties on reliability. To discuss the selection problem of the correlation coefficients from the reliability-based sensitivity point of view, the theory principle of the problem is established based on the results of the reliability sensitivity, and the criterion of correlation among random variables is shown. The values of the correlation coefficients are obtained according to the proposed principle and the reliability sensitivity problem is discussed. Numerical studies have shown the following results: (1) If the sensitivity value of correlation coefficient ρ is less than (at what magnitude 0.000 01), then the correlation could be ignored, which could simplify the procedure without introducing additional error. (2) However, as the difference between ρ s, that is the most sensitive to the reliability, and ρ R , that is with the smallest reliability, is less than 0.001, ρ s is suggested to model the dependency of random variables. This could ensure the robust quality of system without the loss of safety requirement. (3) In the case of | E abs|>0.001 and also | E rel|>0.001, ρ R should be employed to quantify the correlation among random variables in order to ensure the accuracy of reliability analysis. Application of the proposed approach could provide a practical routine for mechanical design and manufactory to study the reliability and reliability-based sensitivity of basic design variables in mechanical reliability analysis and design.

  8. Characteristic analysis on UAV-MIMO channel based on normalized correlation matrix.

    Science.gov (United States)

    Gao, Xi jun; Chen, Zi li; Hu, Yong Jiang

    2014-01-01

    Based on the three-dimensional GBSBCM (geometrically based double bounce cylinder model) channel model of MIMO for unmanned aerial vehicle (UAV), the simple form of UAV space-time-frequency channel correlation function which includes the LOS, SPE, and DIF components is presented. By the methods of channel matrix decomposition and coefficient normalization, the analytic formula of UAV-MIMO normalized correlation matrix is deduced. This formula can be used directly to analyze the condition number of UAV-MIMO channel matrix, the channel capacity, and other characteristic parameters. The simulation results show that this channel correlation matrix can be applied to describe the changes of UAV-MIMO channel characteristics under different parameter settings comprehensively. This analysis method provides a theoretical basis for improving the transmission performance of UAV-MIMO channel. The development of MIMO technology shows practical application value in the field of UAV communication.

  9. Digital image correlation involves an inverse problem: A regularization scheme based on subset size constraint

    Science.gov (United States)

    Zhan, Qin; Yuan, Yuan; Fan, Xiangtao; Huang, Jianyong; Xiong, Chunyang; Yuan, Fan

    2016-06-01

    Digital image correlation (DIC) is essentially implicated in a class of inverse problem. Here, a regularization scheme is developed for the subset-based DIC technique to effectively inhibit potential ill-posedness that likely arises in actual deformation calculations and hence enhance numerical stability, accuracy and precision of correlation measurement. With the aid of a parameterized two-dimensional Butterworth window, a regularized subpixel registration strategy is established, in which the amount of speckle information introduced to correlation calculations may be weighted through equivalent subset size constraint. The optimal regularization parameter associated with each individual sampling point is determined in a self-adaptive way by numerically investigating the curve of 2-norm condition number of coefficient matrix versus the corresponding equivalent subset size, based on which the regularized solution can eventually be obtained. Numerical results deriving from both synthetic speckle images and actual experimental images demonstrate the feasibility and effectiveness of the set of newly-proposed regularized DIC algorithms.

  10. Data Accuracy Model for Distributed Clustering Algorithm based on Spatial Data Correlation in Wireless Sensor Networks

    CERN Document Server

    Karjee, Jyotirmoy

    2011-01-01

    Objective: The main objective of this paper is to construct a distributed clustering algorithm based upon spatial data correlation among sensor nodes and perform data accuracy for each distributed cluster at their respective cluster head node. Design Procedure/Approach: We investigate that due to deployment of high density of sensor nodes in the sensor field, spatial data are highly correlated among sensor nodes in spatial domain. Based on high data correlation among sensor nodes, we propose a non -overlapping irregular distributed clustering algorithm with different sizes to collect most accurate or precise data at the cluster head node for each respective distributed cluster. To collect the most accurate data at the cluster head node for each distributed cluster in sensor field, we propose a Data accuracy model and compare the results with Information accuracy model. Finding: Simulation results shows that our propose Data accuracy model collects more accurate data and gives better performance than Informati...

  11. Reusability and Stability Tests of Calcium Oxide Based Catalyst (K2O/CaO-ZnO for Transesterification of Soybean Oil to Biodiesel

    Directory of Open Access Journals (Sweden)

    Istadi Istadi

    2016-03-01

    Full Text Available This paper was purposed for testing reusability and stability of calcium oxide-based catalyst (K2O/CaO-ZnO over transesterification reaction of soybean oil with methanol to produce biodiesel. The K2O/CaO-ZnO catalyst was synthesized by co-precipitation method of calcium and zinc nitrates followed by impregnation of potassium nitrate. The fresh and used catalysts were tested after regeneration. The catalysts were characterized by Scanning Electron Microscopy (SEM, X-ray Diffraction (XRD, and BET Surface Area in order to compare the catalyst structure between the fresh and used catalysts. The catalyst testing in transesterification proses was carried out at following operating conditions, i.e. catalyst weight of 6 wt.%, oil to methanol mole ratio of 1:15, and temperature of 60 oC. In addition, metal oxide leaching of K2O/CaO-ZnO catalyst during reaction was also tested. From the results, the catalysts exhibited high catalytic activity (80% fatty acid methyl ester (FAME yield after three-cycles of usage and acceptable reusability after regeneration. The catalyst also showed acceptable stability of catalytic activity, even after three-cycles of usage. Copyright © 2016 BCREC GROUP. All rights reserved Received: 10th November 2015; Revised: 16th January 2016; Accepted: 16th January 2016 How to Cite: Istadi, I., Mabruro, U., Kalimantini, B.A.,  Buchori, L., Anggoro, D.D. (2016. Reusability and Stability Tests of Calcium Oxide Based Catalyst (K2O/CaO-ZnO for Transesterification of Soybean Oil to Biodiesel. Bulletin of Chemical Reaction Engineering & Catalysis, 11 (1: 34-39. (doi:10.9767/bcrec.11.1.413.34-39 Permalink/DOI: http://dx.doi.org/10.9767/bcrec.11.1.413.34-39

  12. Towards a global-scale ambient noise cross-correlation data base

    Science.gov (United States)

    Ermert, Laura; Fichtner, Andreas; Sleeman, Reinoud

    2014-05-01

    We aim to obtain a global-scale data base of ambient seismic noise correlations. This database - to be made publicly available at ORFEUS - will enable us to study the distribution of microseismic and hum sources, and to perform multi-scale full waveform inversion for crustal and mantle structure. Ambient noise tomography has developed into a standard technique. According to theory, cross-correlations equal inter-station Green's functions only if the wave field is equipartitioned or the sources are isotropically distributed. In an attempt to circumvent these assumptions, we aim to investigate possibilities to directly model noise cross-correlations and invert for their sources using adjoint techniques. A data base containing correlations of 'gently' preprocessed noise, excluding preprocessing steps which are explicitly taken to reduce the influence of a non-isotropic source distribution like spectral whitening, is a key ingredient in this undertaking. Raw data are acquired from IRIS/FDSN and ORFEUS. We preprocess and correlate the time series using a tool based on the Python package Obspy which is run in parallel on a cluster of the Swiss National Supercomputing Centre. Correlation is done in two ways: Besides the classical cross-correlation function, the phase cross-correlation is calculated, which is an amplitude-independent measure of waveform similarity and therefore insensitive to high-energy events. Besides linear stacks of these correlations, instantaneous phase stacks are calculated which can be applied as optional weight, enhancing coherent portions of the traces and facilitating the emergence of a meaningful signal. The _STS1 virtual network by IRIS contains about 250 globally distributed stations, several of which have been operating for more than 20 years. It is the first data collection we will use for correlations in the hum frequency range, as the STS-1 instrument response is flat in the largest part of the period range where hum is observed, up to a

  13. Pleasant/Unpleasant Filtering for Affective Image Retrieval Based on Cross-Correlation of EEG Features

    Directory of Open Access Journals (Sweden)

    Keranmu Xielifuguli

    2014-01-01

    Full Text Available People often make decisions based on sensitivity rather than rationality. In the field of biological information processing, methods are available for analyzing biological information directly based on electroencephalogram: EEG to determine the pleasant/unpleasant reactions of users. In this study, we propose a sensitivity filtering technique for discriminating preferences (pleasant/unpleasant for images using a sensitivity image filtering system based on EEG. Using a set of images retrieved by similarity retrieval, we perform the sensitivity-based pleasant/unpleasant classification of images based on the affective features extracted from images with the maximum entropy method: MEM. In the present study, the affective features comprised cross-correlation features obtained from EEGs produced when an individual observed an image. However, it is difficult to measure the EEG when a subject visualizes an unknown image. Thus, we propose a solution where a linear regression method based on canonical correlation is used to estimate the cross-correlation features from image features. Experiments were conducted to evaluate the validity of sensitivity filtering compared with image similarity retrieval methods based on image features. We found that sensitivity filtering using color correlograms was suitable for the classification of preferred images, while sensitivity filtering using local binary patterns was suitable for the classification of unpleasant images. Moreover, sensitivity filtering using local binary patterns for unpleasant images had a 90% success rate. Thus, we conclude that the proposed method is efficient for filtering unpleasant images.

  14. Multi-component based cross correlation beat detection in electrocardiogram analysis

    Directory of Open Access Journals (Sweden)

    Owens Frank J

    2004-07-01

    Full Text Available Abstract Background The first stage in computerised processing of the electrocardiogram is beat detection. This involves identifying all cardiac cycles and locating the position of the beginning and end of each of the identifiable waveform components. The accuracy at which beat detection is performed has significant impact on the overall classification performance, hence efforts are still being made to improve this process. Methods A new beat detection approach is proposed based on the fundamentals of cross correlation and compared with two benchmarking approaches of non-syntactic and cross correlation beat detection. The new approach can be considered to be a multi-component based variant of traditional cross correlation where each of the individual inter-wave components are sought in isolation as opposed to being sought in one complete process. Each of three techniques were compared based on their performance in detecting the P wave, QRS complex and T wave in addition to onset and offset markers for 3000 cardiac cycles. Results Results indicated that the approach of multi-component based cross correlation exceeded the performance of the two benchmarking techniques by firstly correctly detecting more cardiac cycles and secondly provided the most accurate marker insertion in 7 out of the 8 categories tested. Conclusion The main benefit of the multi-component based cross correlation algorithm is seen to be firstly its ability to successfully detect cardiac cycles and secondly the accurate insertion of the beat markers based on pre-defined values as opposed to performing individual gradient searches for wave onsets and offsets following fiducial point location.

  15. Temporal Correlation-Based Spatial Filtering of Rician Noise for Functional MRIs

    Institute of Scientific and Technical Information of China (English)

    Amir. A. Khaliq; I. M. Qureshi; Jawad. A. Shah

    2012-01-01

    A novel correlation-based filter is presented for de-noising functional magnetic resonance imaging (fMRI) data. Temporal correlation-based exponential weights are defined for spatial smoothing of the data, with bias reduction using estimated noise variance. The proposed scheme is tested on simulated and real fMRI data. Finally, the results are compared with conventional filters. The method is found to be effectively suppressing the Rician noise in fMRI data, while improving the SNR.%A novel correlation-based filter is presented for de-noising functional magnetic resonance imaging (fMRI) data.Temporal correlation-based exponential weights are defined for spatial smoothing of the data,with bias reduction using estimated noise variance.The proposed scheme is tested on simulated and real fMRI data.Finally,the results are compared with conventional filters.The method is found to be effectively suppressing the Rician noise in fMRI data,while improving the SNR.

  16. Volatility and correlation-based systemic risk measures in the US market

    Science.gov (United States)

    Civitarese, Jamil

    2016-10-01

    This paper deals with the problem of how to use simple systemic risk measures to assess portfolio risk characteristics. Using three simple examples taken from previous literature, one based on raw and partial correlations, another based on the eigenvalue decomposition of the covariance matrix and the last one based on an eigenvalue entropy, a Granger-causation analysis revealed some of them are not always a good measure of risk in the S&P 500 and in the VIX. The measures selected do not Granger-cause the VIX index in all windows selected; therefore, in the sense of risk as volatility, the indicators are not always suitable. Nevertheless, their results towards returns are similar to previous works that accept them. A deeper analysis has shown that any symmetric measure based on eigenvalue decomposition of correlation matrices, however, is not useful as a measure of "correlation" risk. The empirical counterpart analysis of this proposition stated that negative correlations are usually small and, therefore, do not heavily distort the behavior of the indicator.

  17. Neural Correlates of Communication Skill and Symptom Severity in Autism: A Voxel-Based Morphometry Study

    Science.gov (United States)

    Parks, Lauren K.; Hill, Dina E.; Thoma, Robert J.; Euler, Matthew J.; Lewine, Jeffrey D.; Yeo, Ronald A.

    2009-01-01

    Although many studies have compared the brains of normal controls and individuals with autism, especially older, higher-functioning individuals with autism, little is known of the neural correlates of the vast clinical heterogeneity characteristic of the disorder. In this study, we used voxel-based morphometry (VBM) to examine gray matter…

  18. 3D CFD computations of trasitional flows using DES and a correlation based transition model

    DEFF Research Database (Denmark)

    Sørensen, Niels N.; Bechmann, Andreas; Zahle, Frederik

    2011-01-01

    The present article describes the application of the correlation based transition model of Menter et al. in combination with the Detached Eddy Simulation (DES) methodology to two cases with large degree of flow separation typically considered difficult to compute. Firstly, the flow is computed over...

  19. Environmental correlates of cycling: Evaluating urban form and location effects based on Danish micro-data

    DEFF Research Database (Denmark)

    Nielsen, Thomas Alexander Sick; Olafsson, Anton Stahl; Carstensen, Trine Agervig;

    2013-01-01

    The paper analyses the environmental correlates of cycling based on Danish transportation and urban form micro-data. The results show that established walkability factors such as density, connectivity and diversity are related to cycling, but access to retail concentrations/centres, public transp...

  20. Prevalence and structural correlates of gender based violence among a prospective cohort of female sex workers

    OpenAIRE

    Shannon, Kate; Kerr, T.; Strathdee, S.A.; Shoveller, J; Montaner, J S; Tyndall, M W

    2009-01-01

    Objective To examine the prevalence and structural correlates of gender based violence against female sex workers in an environment of criminalised prostitution. Design Prospective observational study. Setting Vancouver, Canada during 2006-8. Participants Female sex workers 14 years of age or older (inclusive of transgender women) who used illicit drugs (excluding marijuana) and engaged in street level sex work. Main outcome measure Self reported gender based violence. Results Of 267 female s...

  1. Copula-based dynamic conditional correlation multiplicative error processes : [Version 18 April 2013

    OpenAIRE

    Bodnar, Taras; Hautsch, Nikolaus

    2013-01-01

    We introduce a copula-based dynamic model for multivariate processes of (non-negative) high-frequency trading variables revealing time-varying conditional variances and correlations. Modeling the variables’ conditional mean processes using a multiplicative error model we map the resulting residuals into a Gaussian domain using a Gaussian copula. Based on high-frequency volatility, cumulative trading volumes, trade counts and market depth of various stocks traded at the NYSE, we show that the ...

  2. DNA-based nanobiostructured devices: The role of quasiperiodicity and correlation effects

    International Nuclear Information System (INIS)

    The purpose of this review is to present a comprehensive and up-to-date account of the main physical properties of DNA-based nanobiostructured devices, stressing the role played by their quasi-periodicity arrangement and correlation effects. Although the DNA-like molecule is usually described as a short-ranged correlated random ladder, artificial segments can be grown following quasiperiodic sequences as, for instance, the Fibonacci and Rudin–Shapiro ones. They have interesting properties like a complex fractal spectra of energy, which can be considered as their indelible mark, and collective properties that are not shared by their constituents. These collective properties are due to the presence of long-range correlations, which are expected to be reflected somehow in their various spectra (electronic transmission, density of states, etc.) defining another description of disorder. Although long-range correlations are responsible for the effective electronic transport at specific resonant energies of finite DNA segments, much of the anomalous spread of an initially localized electron wave-packet can be accounted by short-range pair correlations, suggesting that an approach based on the inclusion of further short-range correlations on the nucleotide distribution leads to an adequate description of the electronic properties of DNA segments. The introduction of defects may generate states within the gap, and substantially improves the conductance, specially of finite branches. They usually become exponentially localized for any amount of disorder, and have the property to tailor the electronic transport properties of DNA-based nanoelectronic devices. In particular, symmetric and antisymmetric correlations have quite distinct influence on the nature of the electronic states, and a diluted distribution of defects lead to an anomalous diffusion of the electronic wave-packet. Nonlinear contributions, arising from the coupling between electrons and the molecular

  3. DNA-based nanobiostructured devices: The role of quasiperiodicity and correlation effects

    Energy Technology Data Exchange (ETDEWEB)

    Albuquerque, E.L., E-mail: eudenilson@gmail.com [Departamento de Biofísica e Farmacologia, Universidade Federal do Rio Grande do Norte, 59072-970, Natal-RN (Brazil); Fulco, U.L. [Departamento de Biofísica e Farmacologia, Universidade Federal do Rio Grande do Norte, 59072-970, Natal-RN (Brazil); Freire, V.N. [Departamento de Física, Universidade Federal do Ceará, 60455-760, Fortaleza-CE (Brazil); Caetano, E.W.S. [Instituto Federal de Educação, Ciência e Tecnologia do Ceará, 60040-531, Fortaleza-CE (Brazil); Lyra, M.L.; Moura, F.A.B.F. de [Instituto de Física, Universidade Federal de Alagoas, 57072-970, Maceió-AL (Brazil)

    2014-02-01

    The purpose of this review is to present a comprehensive and up-to-date account of the main physical properties of DNA-based nanobiostructured devices, stressing the role played by their quasi-periodicity arrangement and correlation effects. Although the DNA-like molecule is usually described as a short-ranged correlated random ladder, artificial segments can be grown following quasiperiodic sequences as, for instance, the Fibonacci and Rudin–Shapiro ones. They have interesting properties like a complex fractal spectra of energy, which can be considered as their indelible mark, and collective properties that are not shared by their constituents. These collective properties are due to the presence of long-range correlations, which are expected to be reflected somehow in their various spectra (electronic transmission, density of states, etc.) defining another description of disorder. Although long-range correlations are responsible for the effective electronic transport at specific resonant energies of finite DNA segments, much of the anomalous spread of an initially localized electron wave-packet can be accounted by short-range pair correlations, suggesting that an approach based on the inclusion of further short-range correlations on the nucleotide distribution leads to an adequate description of the electronic properties of DNA segments. The introduction of defects may generate states within the gap, and substantially improves the conductance, specially of finite branches. They usually become exponentially localized for any amount of disorder, and have the property to tailor the electronic transport properties of DNA-based nanoelectronic devices. In particular, symmetric and antisymmetric correlations have quite distinct influence on the nature of the electronic states, and a diluted distribution of defects lead to an anomalous diffusion of the electronic wave-packet. Nonlinear contributions, arising from the coupling between electrons and the molecular

  4. On exploiting interbeat correlation in compressive sensing-based ECG compression

    Science.gov (United States)

    Polania, Luisa F.; Carrillo, Rafael E.; Blanco-Velasco, Manuel; Barner, Kenneth E.

    2012-06-01

    Compressive Sensing (CS) is an emerging data acquisition scheme with the potential to reduce the number of measurements required by the Nyquist sampling theorem to acquire sparse signals. We recently used the interbeat correlation to find the common support between jointly sparse adjacent heartbeats. In this paper, we fully exploit this correlation to find the magnitude, in addition to the support of the significant coefficients in the sparse domain. The approach used for this purpose is based on sparse Bayesian learning algorithms due to its superior performance compared to other reconstruction algorithms and the fact that being a probabilistic approach facilitates the incorporation of correlation information. The reconstruction includes, in the first place, the detection of the R peaks and the length normalization of ECG cycles to take advantage of the quasi-periodic structure. Since the common support reduces as the number of heartbeats increases, we propose the use of a sliding window where the support maintains approximately constant across cycles. The sparse Bayesian algorithm adaptively learns and exploits the high correlation between the heartbeats in the constructed window. Experimental results show that the proposed method reduces significantly the number of measurements required to achieve good reconstruction quality, validating the potential of using correlation information in compressed sensing-based ECG compression.

  5. [Improving the temperature robustness of the DOAS based on two-dimensional correlation spectroscopy technology].

    Science.gov (United States)

    Li, Hong-lian; Wei, Yong-jie; Lü, Chuan-ming; Chen, Wen-liang

    2013-09-01

    The accuracy of the measurement results will be influenced by the ambient temperature in the real-time monitoring based on Differential Optical Absorption Spectroscopy (DOAS). A novel method to improve the temperature robustness of DOAS technology is adopted by two-dimensional correlation spectroscopy technology. Two-dimensional correlation is used to analyse the SO2 absorption cross section at different temperatures. The diagonal slices of synchronization correlation spectroscopy which come from dynamic absorption cross section are obtained. The wavelength 300.5-310 nm is used as the preferred inversion wavelength range based on the slices. The field measurement results and reference value are compared. Results show that the 24-hour average measurement error is 22.5% at 290-310 nm and that at 300.5-310 nm is 9.9%. The correlation coefficients are 0.9496 and 0.7808, respectively. Two-dimensional correlation DOAS technology can be applied to enhance the robustness of temperature, and to improve the accuracy of the measurement results. PMID:24369636

  6. Cluster-based statistics for brain connectivity in correlation with behavioral measures.

    Directory of Open Access Journals (Sweden)

    Cheol E Han

    Full Text Available Graph theoretical approaches have successfully revealed abnormality in brain connectivity, in particular, for contrasting patients from healthy controls. Besides the group comparison analysis, a correlational study is also challenging. In studies with patients, for example, finding brain connections that indeed deepen specific symptoms is interesting. The correlational study is also beneficial since it does not require controls, which are often difficult to find, especially for old-age patients with cognitive impairment where controls could also have cognitive deficits due to normal ageing. However, one of the major difficulties in such correlational studies is too conservative multiple comparison correction. In this paper, we propose a novel method for identifying brain connections that are correlated with a specific cognitive behavior by employing cluster-based statistics, which is less conservative than other methods, such as Bonferroni correction, false discovery rate procedure, and extreme statistics. Our method is based on the insight that multiple brain connections, rather than a single connection, are responsible for abnormal behaviors. Given brain connectivity data, we first compute a partial correlation coefficient between every edge and the behavioral measure. Then we group together neighboring connections with strong correlation into clusters and calculate their maximum sizes. This procedure is repeated for randomly permuted assignments of behavioral measures. Significance levels of the identified sub-networks are estimated from the null distribution of the cluster sizes. This method is independent of network construction methods: either structural or functional network can be used in association with any behavioral measures. We further demonstrated the efficacy of our method using patients with subcortical vascular cognitive impairment. We identified sub-networks that are correlated with the disease severity by exploiting diffusion

  7. L-lactide ring open polymerization with catalyst based on calcium compounds; Polimerizacao via abertura de anel de L-lactideo com compostos a base de calcio

    Energy Technology Data Exchange (ETDEWEB)

    Palermo, Luiz C.M.; Dias, Marcos L.; Silvino, Alexandre C. [Universidade Federal do Rio de Janeiro (IMA/UFRJ), RJ (Brazil). Inst. de Macromoleculas Professora Eloisa Mano

    2009-07-01

    The bulk ring opening polymerization of L-lactide using calcium methoxide and calcium octoate as catalysts at different lactide/calcium (LA:Ca) molar ratio was investigated. The reactions were carried out at LA:Ca ratio of 100, 250, 500, 1,000 and 5,000 at 180 deg C. The poly(L-lactic acid) (PLLA) were characterized according the molecular weight, microstructure and thermal properties. Higher polymerization yields was 66 wt % in the LA:Ca ratio= 100. The polydispersity ranged from 1.20 to 1.44 and the molecular weight varied from 8,500 to 19,500. Results of X-ray diffraction indicated that the polymers present high crystallinity, particularly the PLLA obtained with LA:Ca molar ration= 1,000 and 5,000. (author)

  8. Serum calcium in pulmonary tuberculosis

    OpenAIRE

    Subhash C. Sharma

    1981-01-01

    Serum calcium was studied serially in 94 patients with active pulmonary tuberculosis. An equal number of age- and sex-matched patients with chronic obstructive pulmonary disease were controls. Seventy patients in the study group were normocalcaemic and 10 were hypercalcaemic. These 10 were on a higher supplement of vitamin D than the 70 normocalcaemic patients. There was a positive correlation between the daily vitamin intake and the degree and duration of hypercalcaemia. None of the controls...

  9. Application of reference point indentation for micro-mechanical surface characterization of calcium silicate based dental materials.

    Science.gov (United States)

    Antonijević, Djordje; Milovanović, Petar; Riedel, Christoph; Hahn, Michael; Amling, Michael; Busse, Björn; Djurić, Marija

    2016-04-01

    The objective of this study was to elucidate micromechanical properties of Biodentine and two experimental calcium silicate cements (CSCs) using Reference Point Indentation (RPI). Biomechanical characteristics of the cement type and the effects of a radiopacifier, liquid components, acid etching treatment and bioactivation in simulated body fluid (SBF) were investigated by measuring the microhardness, average unloading slope (Avg US) and indentation distance increase (IDI). Biodentine had a greater microhardness than the experimental CSCs, while the Avg US and IDI values were not significantly different among investigated materials. There was a statistically significant difference in microhardness and IDI values between pure CSCs and radiopacified cements (p < 0.05). Micromechanical properties were not affected by different liquid components used. Acid-etching treatment reduced Biodentine's microhardness while cements' immersion in SBF resulted in greater microhardness and higher IDI values compared to the control group. Clearly, the physiological environment and the cements' composition affect their surface micromechanical properties. The addition of calcium chloride and CSCs' immersion in SBF are beneficial for CSCs' micromechanical performance, while the addition of radiopacifiers and acid etching treatment weaken the CSCs' surface. Application of RPI aids with the characterization of micromechanical properties of synthetic materials' surfaces. PMID:26888441

  10. Diagnosis method based on wavelet coefficient scale relativity correlation dimension for fault

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Correlation dimension as a tool to describe machinery condition is introduced.Vibration signals of the fan under different working conditions are analyzed using a threshold filtering algorithm based on the region relativity of the wavelet coefficients for reducing noise.The result shows that the characteristics of the signal could be preserved completely.The correlation dimension is able to identify conditions of the fan with faults compared with the normal condition,thereby providing an effective technology for condition monitoring and fault diagnosis of mechanical equipment.

  11. Pair correlation functions of FeAs-based superconductors: Quantum Monte Carlo study

    Science.gov (United States)

    Kashurnikov, V. A.; Krasavin, A. V.

    2015-01-01

    The new generalized quantum continuous time world line Monte Carlo algorithm was developed to calculate pair correlation functions for two-dimensional FeAs-clusters modeling of iron-based superconductors within the framework of the two-orbital model. The analysis of pair correlations depending on the cluster size, temperature, interaction, and the type of symmetry of the order parameter is carried out. The data obtained for clusters with sizes up to 1 0x1 0 FeAs-cells favor the possibility of an effective charge carrier's attraction that is corresponding the A1g-symmetry, at some parameters of interaction.

  12. A Correlation Based Strategy for the Acceleration of Nonlocal Means Filtering Algorithm

    Directory of Open Access Journals (Sweden)

    Junfeng Zhang

    2016-01-01

    Full Text Available Although the nonlocal means (NLM algorithm takes a significant step forward in image filtering field, it suffers from a high computational complexity. To deal with this drawback, this paper proposes an acceleration strategy based on a correlation operation. Instead of per-pixel processing, this approach performs a simultaneous calculation of all the image pixels with the help of correlation operators. Complexity analysis and experimental results are reported and show the advantage of the proposed algorithm in terms of computation and time cost.

  13. Financial Support for Rural Cooperative Economy in China Based on Grey Correlation Analysis

    Institute of Scientific and Technical Information of China (English)

    Fuchang; XU; Chuandong; WANG

    2015-01-01

    This paper firstly analyzed current situations of financial support for rural cooperative economy in China and tested the correlation between rural finance and rural cooperative economy using the grey correlation analysis method. Results indicate that there is a close relationship between amount,structure and efficiency of rural finance and development of rural cooperative economy. The amount of rural finance has the largest promotion function to development of rural cooperative economy,the next is rural finance structure,and the least is efficiency of rural finance. Based on research conclusions,it came up with pertinent policy recommendations.

  14. Econometric analysis of realized covariation: high frequency based covariance, regression, and correlation in financial economics

    DEFF Research Database (Denmark)

    Barndorff-Nielsen, Ole Eiler; Shephard, N.

    2004-01-01

    This paper analyses multivariate high frequency financial data using realized covariation. We provide a new asymptotic distribution theory for standard methods such as regression, correlation analysis, and covariance. It will be based on a fixed interval of time (e.g., a day or week), allowing...... the number of high frequency returns during this period to go to infinity. Our analysis allows us to study how high frequency correlations, regressions, and covariances change through time. In particular we provide confidence intervals for each of these quantities....

  15. Calcium channel blocker overdose

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/002580.htm Calcium channel blocker overdose To use the sharing features on this page, please enable JavaScript. Calcium channel blockers are a type of medicine used ...

  16. Fenoprofen calcium overdose

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/002649.htm Fenoprofen calcium overdose To use the sharing features on this page, please enable JavaScript. Fenoprofen calcium is a type of medicine called a nonsteroidal ...

  17. Virus and calcium: an unexpected tandem to optimize insecticide efficacy.

    Science.gov (United States)

    Apaire-Marchais, Véronique; Ogliastro, Mylène; Chandre, Fabrice; Pennetier, Cédric; Raymond, Valérie; Lapied, Bruno

    2016-04-01

    The effective control of insect pests is based on the rational use of the most efficient and safe insecticide treatments. To increase the effects of classical insecticides and to avoid the ability of certain pest insects to develop resistance, it is essential to propose novel strategies. Previous studies have shown that calcium-dependent phosphorylation/dephosphorylation is now considered as a new cellular mechanism for increasing the target sensitivity to insecticides. Because it is known that virus entry is correlated with intracellular calcium concentration rise, this report attempts to present the most important data relevant to the feasibility of combining an insect virus such as baculovirus or densovirus with an insecticide. In this case, the insect virus is not used as a bioinsecticide but acts as a synergistic agent able to trigger calcium rise and to activate calcium-dependent intracellular signalling pathways involved in the increase of the membrane receptors and/or ion channels sensitivity to insecticides. This virus-insecticide mixture represents a promising alternative to optimize the efficacy of insecticides against insect pests while reducing the doses. PMID:26743399

  18. Aircraft Target Classification Based on Correlation Features from Time-domain Echoes

    Directory of Open Access Journals (Sweden)

    Du Lan

    2015-12-01

    Full Text Available This paper reports the classification of helicopters, propeller-driven aircraft, and turbojet based on differences in their time-domain modulation periods using a conventional radar system. First, we determine the modulation periods of their time-domain echoes. Then, based on the differences in the time-domain modulation periods, we propose a method for the extraction of time-domain correlation features. Finally, based on the simulated and measured data, via a support vector machine classifier, it is proved that the time-domain correlation features can yield the good classification performance, even with the relatively low pulse repetition frequency, which may induce the ambiguity in Doppler-frequency domain.

  19. Calcium and Mitosis

    Science.gov (United States)

    Hepler, P.

    1983-01-01

    Although the mechanism of calcium regulation is not understood, there is evidence that calcium plays a role in mitosis. Experiments conducted show that: (1) the spindle apparatus contains a highly developed membrane system that has many characteristics of sarcoplasmic reticulum of muscle; (2) this membrane system contains calcium; and (3) there are ionic fluxes occurring during mitosis which can be seen by a variety of fluorescence probes. Whether the process of mitosis can be modulated by experimentally modulating calcium is discussed.

  20. Correlation dimension based nonlinear analysis of network traffics with different application protocols

    Institute of Scientific and Technical Information of China (English)

    Wang Jun-Song; Yuan Jing; Li Qiang; Yuan Rui-Xi

    2011-01-01

    This paper uses a correlation dimension based nonlinear analysis approach to analyse the dynamics of network traffics with three different application protocols-HTTP, FTP and SMTP. First, the phase space is reconstructed and the embedding parameters are obtained by the mutual information method. Secondly, the correlation dimensions of three different traffics are calculated and the results of analysis have demonstrated that the dynamics of the three different application protocol traffics is different from each other in nature, i.e. HTTP and FTP traffics are chaotic,furthermore, the former is more complex than the later; on the other hand, SMTP traffic is stochastic. It is shown that correlation dimension approach is an efficient method to understand and to characterize the nonlinear dynamics of HTTP, FTP and SMTP protocol network traffics. This analysis provided insight into and a more accurate understanding of nonlinear dynamics of internet traffics which have a complex mixture of chaotic and stochastic components.

  1. Pair correlations in iron-based superconductors: Quantum Monte Carlo study

    Energy Technology Data Exchange (ETDEWEB)

    Kashurnikov, V.A.; Krasavin, A.V., E-mail: avkrasavin@gmail.com

    2014-08-01

    The new generalized quantum continuous time world line Monte Carlo algorithm was developed to calculate pair correlation functions for two-dimensional FeAs-clusters modeling of iron-based superconductors using a two-orbital model. The data obtained for clusters with sizes up to 10×10 FeAs-cells favor the possibility of an effective charge carrier's attraction that is corresponding the A{sub 1g}-symmetry, at some parameters of interaction. The analysis of pair correlations depending on the cluster size, temperature, interaction, and the type of symmetry of the order parameter is carried out. - Highlights: • New generalized quantum continuous time world line Monte Carlo algorithm is developed. • Pair correlation functions for two-dimensional FeAs-clusters are calculated. • Parameters of two-orbital model corresponding to attraction of carriers are defined.

  2. Time-Correlated Photon Counting (TCPC) technique based on a photon-number-resolving photodetector

    Science.gov (United States)

    Li, Baicheng; Miao, Quanlong; Wang, Shenyuan; Hui, Debin; Zhao, Tianqi; Liang, Kun; Yang, Ru; Han, Dejun

    2016-05-01

    In this report, we present Time-Correlated Photon Counting (TCPC) technique and its applications in time-correlated Raman spectroscopy. The main difference between TCPC and existing Time-Correlated Single Photon Counting (TCSPC) is that the TCPC employs a photon-number-resolving photodetector (SiPM, silicon photomultiplier) and measures exact photon number rather than counting single photon by reducing pulse light intensity, thus high measurement speed and efficiency can be expected. A home-made Raman spectrometer has demonstrated an Instrument Response Function (IRF) ~100ps (FWHM) based on TCPC with a strip SiPM (1mm×0.05mm, containing 500 micro cells), fast and weak Raman signals was separated from slow and strong fluorescence background of bulk trinitrotoluene TNT sample. The original Raman spectrum of bulk TNT, measured by TCPC technique, is compared with the result obtained by a commercial Micro-Raman Spectrometer.

  3. Analysis for Suspension Hardpoint of Formula SAE Car Based on Correlation Theory

    Directory of Open Access Journals (Sweden)

    Xintian Liu

    2013-12-01

    Full Text Available According to the correlation of the hardpoints, double wishbone suspension of Formula SAE Car can be improved and optimized. For Formula SAE car, performance and kinetic characteristic of the suspension follow very closely to handling stability, comfort ability, handling of steering and service life of tire, etc. Double wishbone suspension is chosen as front suspension of Formula SAE car in the paper. Based on the multi-body dynamics and suspension kinematics theory, simulation model of front suspension is built and analyzed. With correlation theory, the correlation for the hardpoints of the suspension is studied and discussed. Through all the testing, not only a lot of four wheel alignment parameter variations can be obtained, but also the rational designing for hardpoints which can provide an useful reference for vehicle designing.

  4. Calcium hydroxide: study based on scientific evidences Hidróxido de cálcio: estudo baseado em evidências científicas

    Directory of Open Access Journals (Sweden)

    Carlos Estrela

    2003-12-01

    Full Text Available The characteristics of calcium hydroxide come from its dissociation into calcium and hydroxyl ions. The action of these ions on tissues and bacteria explains the biological and antimicrobial properties of this substance. Under the conditions of this retrospective of literature, based on scientific evidences, it is possible to state that: 1. Dentin is considered the best pulpal protective, and calcium hydroxide has proved, through numerous studies, its capability of inducing the formation of a mineralized bridge over pulpal tissue. 2. It is necessary, whenever possible, to provide time for calcium hydroxide paste to manifest its potential of action on the microorganisms present in endodontic infections. The maintenance of a high concentration of hydroxyl ions can change bacteria enzymatic activity and promote its inactivation. 3. The site of action of hydroxyl ions of calcium hydroxide includes the enzymes in the cytoplasmic membrane. This medication has a large scope of action, and therefore is effective on a wide range of microorganisms, regardless their metabolic capability. In microbial world, cytoplasmic membranes are similar, irrespective from microorganisms morphological, tinctorial and respiratory characteristics, which means that this medication has a similar effect on aerobic, anaerobic, Gram-positive and Gram-negative bacteria. 4. Calcium hydroxide as temporary dressing used between appointments promotes better results on the periapical healing process than the treatment in one appointment.As características do hidróxido de cálcio se desenvolvem a partir da dissociação em íons cálcio e hidroxila. A ação desses íons nos tecidos e bactérias explica as características biológicas e antimicrobianas dessa substância. Por meio desta retrospectiva da literatura, baseada em evidências científicas, é possível afirmar que: 1. A dentina é considerada a melhor proteção pulpar, e o hidróxido de cálcio provou, através de

  5. Calcium en cardioplegie

    NARCIS (Netherlands)

    Ruigrok, T.J.C.; Meijler, F.L.

    1985-01-01

    Coronary perfusion with a calcium-free solution, followed by reperfusion with a calcium containing solution, may result in acute myocardial cell death and in irreversible loss of the e1ectrical and mechanical activity of the heart. This phenomenon is known as the calcium paradox. A number of cardiop

  6. Characterization of calcium and zinc spatial distributions at the fibrocartilage zone of bone-tendon junction by synchrotron radiation-based micro X-ray fluorescence analysis combined with backscattered electron imaging

    Science.gov (United States)

    Lu, Hongbin; Chen, Can; Wang, Zhanwen; Qu, Jin; Xu, Daqi; Wu, Tianding; Cao, Yong; Zhou, Jingyong; Zheng, Cheng; Hu, Jianzhong

    2015-09-01

    Tendon attaches to bone through a functionally graded fibrocartilage zone, including uncalcified fibrocartilage (UF), tidemark (TM) and calcified fibrocartilage (CF). This transition zone plays a pivotal role in relaxing load transfer between tendon and bone, and serves as a boundary between otherwise structurally and functionally distinct tissue types. Calcium and zinc are believed to play important roles in the normal growth, mineralization, and repair of the fibrocartilage zone of bone-tendon junction (BTJ). However, spatial distributions of calcium and zinc at the fibrocartilage zone of BTJ and their distribution-function relationship are not totally understood. Thus, synchrotron radiation-based micro X-ray fluorescence analysis (SR-μXRF) in combination with backscattered electron imaging (BEI) was employed to characterize the distributions of calcium and zinc at the fibrocartilage zone of rabbit patella-patellar tendon complex (PPTC). For the first time, the unique distributions of calcium and zinc at the fibrocartilage zone of the PPTC were clearly mapped by this method. The distributions of calcium and zinc at the fibrocartilage zone of the PPTC were inhomogeneous. A significant accumulation of zinc was exhibited in the transition region between UF and CF. The highest zinc content (3.17 times of that of patellar tendon) was found in the TM of fibrocartilage zone. The calcium content began to increase near the TM and increased exponentially across the calcified fibrocartilage region towards the patella. The highest calcium content (43.14 times of that of patellar tendon) was in the transitional zone of calcified fibrocartilage region and the patella, approximately 69 μm from the location with the highest zinc content. This study indicated, for the first time, that there is a differential distribution of calcium and zinc at the fibrocartilage zone of PPTC. These observations reveal new insights into region-dependent changes across the fibrocartilage zone of

  7. Correlated noise-based switches and stochastic resonance in a bistable genetic regulation system

    Science.gov (United States)

    Wang, Can-Jun; Yang, Ke-Li

    2016-07-01

    The correlated noise-based switches and stochastic resonance are investigated in a bistable single gene switching system driven by an additive noise (environmental fluctuations), a multiplicative noise (fluctuations of the degradation rate). The correlation between the two noise sources originates from on the lysis-lysogeny pathway system of the λ phage. The steady state probability distribution is obtained by solving the time-independent Fokker-Planck equation, and the effects of noises are analyzed. The effects of noises on the switching time between the two stable states (mean first passage time) is investigated by the numerical simulation. The stochastic resonance phenomenon is analyzed by the power amplification factor. The results show that the multiplicative noise can induce the switching from "on" → "off" of the protein production, while the additive noise and the correlation between the noise sources can induce the inverse switching "off" → "on". A nonmonotonic behaviour of the average switching time versus the multiplicative noise intensity, for different cross-correlation and additive noise intensities, is observed in the genetic system. There exist optimal values of the additive noise, multiplicative noise and cross-correlation intensities for which the weak signal can be optimal amplified.

  8. Optimizing calcium selective fluorimetric nanospheres.

    Science.gov (United States)

    Kisiel, Anna; Kłucińska, Katarzyna; Gniadek, Marianna; Maksymiuk, Krzysztof; Michalska, Agata

    2015-11-01

    Recently it was shown that optical nanosensors based on alternating polymers e.g. poly(maleic anhydride-alt-1-octadecene) were characterized by a linear dependence of emission intensity on logarithm of concentration over a few of orders of magnitude range. In this work we focus on the material used to prepare calcium selective nanosensors. It is shown that alternating polymer nanosensors offer competitive performance in the absence of calcium ionophore, due to interaction of the nanospheres building blocks with analyte ions. The emission increase corresponds to increase of calcium ions contents in the sample within the range from 10(-4) to 10(-1) M. Further improvement in sensitivity (from 10(-6) to 10(-1) M) and selectivity can be achieved by incorporating calcium ionophore in the nanospheres. The optimal results were obtained for core-shell nanospheres, where the core was prepared from poly(styrene-co-maleic anhydride) and the outer layer from poly(maleic anhydride-alt-1-octadecene). Thus obtained chemosensors were showing linear dependence of emission on logarithm of calcium ions concentration within the range from 10(-7) to 10(-1) M. PMID:26452839

  9. In situ Gelation of Monodisperse Alginate Hydrogel in Microfluidic Channel Based on Mass Transfer of Calcium Ions

    International Nuclear Information System (INIS)

    A microfluidic method for the in situ production of monodispersed alginate hydrogels using biocompatible polymer gelation by crosslinker mass transfer is described. Gelation of the hydrogel was achieved in situ by the dispersed calcium ion in the microfluidic device. The capillary number (Ca) and the flow rate of the disperse phase which are important operating parameters mainly influenced the formation of three distinctive flow regions, such as dripping, jetting, and unstable dripping. Under the formation of dripping region, monodispersed alginate hydrogels having a narrow size distribution (C.V=2.71%) were produced in the microfluidic device and the size of the hydrogels, ranging from 30 to 60 µm, could be easily controlled by varying the flow rate, viscosity, and interfacial tension. This simple microfluidic method for the production of monodisperse alginate hydrogels shows strong potential for use in delivery systems of foods, cosmetics, inks, and drugs, and spherical alginate hydrogels which have biocompatibility will be applied to cell transplantation

  10. In situ Gelation of Monodisperse Alginate Hydrogel in Microfluidic Channel Based on Mass Transfer of Calcium Ions

    Energy Technology Data Exchange (ETDEWEB)

    Song, YoungShin; Lee, Chang-Soo [Chungnam National University, Daejeon (Korea, Republic of)

    2014-10-15

    A microfluidic method for the in situ production of monodispersed alginate hydrogels using biocompatible polymer gelation by crosslinker mass transfer is described. Gelation of the hydrogel was achieved in situ by the dispersed calcium ion in the microfluidic device. The capillary number (Ca) and the flow rate of the disperse phase which are important operating parameters mainly influenced the formation of three distinctive flow regions, such as dripping, jetting, and unstable dripping. Under the formation of dripping region, monodispersed alginate hydrogels having a narrow size distribution (C.V=2.71%) were produced in the microfluidic device and the size of the hydrogels, ranging from 30 to 60 µm, could be easily controlled by varying the flow rate, viscosity, and interfacial tension. This simple microfluidic method for the production of monodisperse alginate hydrogels shows strong potential for use in delivery systems of foods, cosmetics, inks, and drugs, and spherical alginate hydrogels which have biocompatibility will be applied to cell transplantation.

  11. Synthesis, Crystal Structure, and Luminescence Properties of a New Calcium(II Coordination Polymer Based on L-Malic Acid

    Directory of Open Access Journals (Sweden)

    Duraisamy Senthil Raja

    2013-01-01

    Full Text Available A new calcium coordination polymer [Ca(HL-MA]n (H3L-MA = L-malic acid has been solvothermally synthesized. The structure of the newly synthesized complex has been determined by single-crystal X-ray diffraction analysis and further characterized by elemental analysis, reflectance UV-Vis & IR spectra, powder X-ray diffraction (PXRD, and thermogravimetric analysis (TGA. The single crystal structure analysis showed that the complex forms three-dimensional framework. The new Ca(II complex has displayed very high thermal stability which was inferred from TGA and PXRD results. As far as the optical property of the new complex is concerned, the complex emitted its own characteristic sensitized luminescence.

  12. Inter-subject correlation in fMRI: method validation against stimulus-model based analysis.

    Directory of Open Access Journals (Sweden)

    Juha Pajula

    Full Text Available Within functional magnetic resonance imaging (fMRI, the use of the traditional general linear model (GLM based analysis methods is often restricted to strictly controlled research setups requiring a parametric activation model. Instead, Inter-Subject Correlation (ISC method is based on voxel-wise correlation between the time series of the subjects, which makes it completely non-parametric and thus suitable for naturalistic stimulus paradigms such as movie watching. In this study, we compared an ISC based analysis results with those of a GLM based in five distinct controlled research setups. We used International Consortium for Brain Mapping functional reference battery (FRB fMRI data available from the Laboratory of Neuro Imaging image data archive. The selected data included measurements from 37 right-handed subjects, who all had performed the same five tasks from FRB. The GLM was expected to locate activations accurately in FRB data and thus provide good grounds for investigating relationship between ISC and stimulus induced fMRI activation. The statistical maps of ISC and GLM were compared with two measures. The first measure was the Pearson's correlation between the non-thresholded ISC test-statistics and absolute values of the GLM Z-statistics. The average correlation value over five tasks was 0.74. The second was the Dice index between the activation regions of the methods. The average Dice value over the tasks and three threshold levels was 0.73. The results of this study indicated how the data driven ISC analysis found the same foci as the model-based GLM analysis. The agreement of the results is highly interesting, because ISC is applicable in situations where GLM is not suitable, for example, when analyzing data from a naturalistic stimuli experiment.

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-12-01

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

  15. The Electronic Structure of Calcium

    DEFF Research Database (Denmark)

    Jan, J.-P.; Skriver, Hans Lomholt

    1981-01-01

    The electronic structure of calcium under pressure is re-examined by means of self-consistent energy band calculations based on the local density approximation and using the linear muffin-tin orbitals (LMTO) method with corrections to the atomic sphere approximation included. At zero pressure...

  16. Correlation between liquid structure and glass forming ability in glassy Ag-based binary alloys

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The atomic structures of liquid Ag-based binary alloys have been investigated in the solidification process by means of X-ray diffraction. The results of liquid structure show that there is a break point in the mean nearest neighbor distance r1 and the coordination number Nmin for glass-forming liquid, while the correlation radius rc and the coordination number Nmin display a monotone variational trend above the break point. It means glass-forming liquids have a steady changing in structure above liquidus and more inhomogeneous state at liquidus. We conclude that there is a strong correlation between liquid structure and glass forming ability in Ag-based binary alloys.

  17. Predicting the Energy Output of Wind Farms Based on Weather Data: Important Variables and their Correlation

    CERN Document Server

    Vladislavleva, Katya; Neumann, Frank; Wagner, Markus

    2011-01-01

    Wind energy plays an increasing role in the supply of energy world-wide. The energy output of a wind farm is highly dependent on the weather condition present at the wind farm. If the output can be predicted more accurately, energy suppliers can coordinate the collaborative production of different energy sources more efficiently to avoid costly overproductions. With this paper, we take a computer science perspective on energy prediction based on weather data and analyze the important parameters as well as their correlation on the energy output. To deal with the interaction of the different parameters we use symbolic regression based on the genetic programming tool DataModeler. Our studies are carried out on publicly available weather and energy data for a wind farm in Australia. We reveal the correlation of the different variables for the energy output. The model obtained for energy prediction gives a very reliable prediction of the energy output for newly given weather data.

  18. 3D CFD computations of transitional flows using DES and a correlation based transition model

    DEFF Research Database (Denmark)

    Sørensen, Niels N.

    process can be important for the aerodynamic performance. Today, the most widespread approach is to use fully turbulent computations, where the transitional process is ignored and the entire boundary layer on the wings or airfoils is handled by the turbulence model. The correlation based transition model......The report describes the application of the correlation based transition model of of Menter et. al. [1, 2] to the cylinder drag crisis and the stalled flow over an DU-96-W-351 airfoil using the DES methodology. When predicting the flow over airfoils and rotors, the laminar-turbulent transition...... has lately shown promising results, and the present paper describes the application of the model to predict the drag and shedding frequency for flow around a cylinder from sub to super-critical Reynolds numbers. Additionally, the model is applied to the flow around the DU-96 airfoil, at high angles...

  19. Quantum Systems based upon Galois Fields: from Sub-quantum to Super-quantum Correlations

    OpenAIRE

    Chang, Lay Nam; Lewis, Zachary; Minic, Djordje; Takeuchi, Tatsu

    2013-01-01

    In this talk we describe our recent work on discrete quantum theory based on Galois fields. In particular, we discuss how discrete quantum theory sheds new light on the foundations of quantum theory and we review an explicit model of super-quantum correlations we have constructed in this context. We also discuss the larger questions of the origins and foundations of quantum theory, as well as the relevance of super-quantum theory for the quantum theory of gravity.

  20. Integrated evaluation of soil fertility based on grey correlation analysis at regional scales

    OpenAIRE

    Zhang, Yu; Liu, Hua; Bingham, Chris

    2015-01-01

    This paper reports on studies of soil samples from the region of Xiaoliang water conservation station, in China, and its naturally restored forest. 32 indices based on the physical, chemical, microbiological and enzyme properties of the soil are studied, from 9 different vegetation patterns at 45 observation points. Grey correlation analysis and integrated evaluation is used for the analysis of soil fertility. From experimental measurements, it is shown that the integrated evaluation of the s...

  1. Neuromimetic Circuits with Synaptic Devices based on Strongly Correlated Electron Systems

    OpenAIRE

    Ha, Sieu D.; Shi, Jian; Meroz, Yasmine; Mahadevan, L.; Ramanathan, Shriram

    2014-01-01

    Strongly correlated electron systems such as the rare-earth nickelates (RNiO3, R = rare-earth element) can exhibit synapse-like continuous long term potentiation and depression when gated with ionic liquids; exploiting the extreme sensitivity of coupled charge, spin, orbital, and lattice degrees of freedom to stoichiometry. We present experimental real-time, device-level classical conditioning and unlearning using nickelate-based synaptic devices in an electronic circuit compatible with both ...

  2. High-speed secure key distribution over an optical network based on computational correlation imaging.

    Science.gov (United States)

    Li, Shen; Yao, Xu-Ri; Yu, Wen-Kai; Wu, Ling-An; Zhai, Guang-Jie

    2013-06-15

    We present a protocol for an optical key distribution network based on computational correlation imaging, which can simultaneously realize privacy amplification and multiparty distribution. With current technology, the key distribution rate could reach hundreds of Mbit/s with suitable choice of parameters. The setup is simple and inexpensive, and may be employed in real networks where high-speed long-distance secure communication is required. PMID:23939004

  3. Experimental verifications of noise suppression in retinal recognition by using compression-based joint transform correlator

    Science.gov (United States)

    Widjaja, Joewono; Kaewphaluk, Komin

    2014-03-01

    Noise suppression in retinal recognition by using a compression-based joint transform correlator (CBJTC) is experimentally studied. The experimental results show that the noise suppression can be done by compressing targets into a joint-photographic expert group (JPEG) format with appropriate image compression quality. In the case of the weak noise suppression, the improved recognition performance is as high as that of the classical JTC.

  4. Correlation between voxel based morphometry and manual volumetry in magnetic resonance images of the human brain

    OpenAIRE

    Ricardo R. Uchida; Cristina M. Del-Ben; David Araújo; Geraldo Busatto-Filho; Duran, Fábio L.S.; Crippa, José A. S.; Graeff, Frederico G.

    2008-01-01

    This is a comparative study between manual volumetry (MV) and voxel based morphometry (VBM) as methods of evaluating the volume of brain structures in magnetic resonance images. The volumes of the hippocampus and the amygdala of 16 panic disorder patients and 16 healthy controls measured through MV were correlated with the volumes of gray matter estimated by optimized modulated VBM. The chosen structures are composed almost exclusively of gray matter. Using a 4 mm Gaussian filter, statistical...

  5. Correlation between Composition and Properties of Composite Material Based on Scrap Tires

    OpenAIRE

    Mālers, L; Plēsuma, R; Ločmele, L; Kalniņš, M

    2010-01-01

    Purpose of present work is to investigate mechanical and insulation properties of the composite material based on scrap tires and polyurethane-type binder in correlation with composition of composite material. The studies of material’s hardness must be considered as an express-method for estimation of the selected mechanical properties (E and ccompressive stress) of the composite material without direct experimental testing of given parameters. It was shown that composite material must be r...

  6. Calcium signaling and epilepsy.

    Science.gov (United States)

    Steinlein, Ortrud K

    2014-08-01

    Calcium signaling is involved in a multitude of physiological and pathophysiological mechanisms. Over the last decade, it has been increasingly recognized as an important factor in epileptogenesis, and it is becoming obvious that the excess synchronization of neurons that is characteristic for seizures can be linked to various calcium signaling pathways. These include immediate effects on membrane excitability by calcium influx through ion channels as well as delayed mechanisms that act through G-protein coupled pathways. Calcium signaling is able to cause hyperexcitability either by direct modulation of neuronal activity or indirectly through calcium-dependent gliotransmission. Furthermore, feedback mechanisms between mitochondrial calcium signaling and reactive oxygen species are able to cause neuronal cell death and seizures. Unravelling the complexity of calcium signaling in epileptogenesis is a daunting task, but it includes the promise to uncover formerly unknown targets for the development of new antiepileptic drugs.

  7. Wavelet-based cross-correlation analysis of structure scaling in turbulent clouds

    Science.gov (United States)

    Arshakian, Tigran G.; Ossenkopf, Volker

    2016-01-01

    Aims: We propose a statistical tool to compare the scaling behaviour of turbulence in pairs of molecular cloud maps. Using artificial maps with well-defined spatial properties, we calibrate the method and test its limitations to apply it ultimately to a set of observed maps. Methods: We develop the wavelet-based weighted cross-correlation (WWCC) method to study the relative contribution of structures of different sizes and their degree of correlation in two maps as a function of spatial scale, and the mutual displacement of structures in the molecular cloud maps. Results: We test the WWCC for circular structures having a single prominent scale and fractal structures showing a self-similar behaviour without prominent scales. Observational noise and a finite map size limit the scales on which the cross-correlation coefficients and displacement vectors can be reliably measured. For fractal maps containing many structures on all scales, the limitation from observational noise is negligible for signal-to-noise ratios ≳5. We propose an approach for the identification of correlated structures in the maps, which allows us to localize individual correlated structures and recognize their shapes and suggest a recipe for recovering enhanced scales in self-similar structures. The application of the WWCC to the observed line maps of the giant molecular cloud G 333 allows us to add specific scale information to the results obtained earlier using the principal component analysis. The WWCC confirms the chemical and excitation similarity of 13CO and C18O on all scales, but shows a deviation of HCN at scales of up to 7 pc. This can be interpreted as a chemical transition scale. The largest structures also show a systematic offset along the filament, probably due to a large-scale density gradient. Conclusions: The WWCC can compare correlated structures in different maps of molecular clouds identifying scales that represent structural changes, such as chemical and phase transitions

  8. Relationship between serum calcium and CA 19-9 levels in colorectal cancer

    Institute of Scientific and Technical Information of China (English)

    Peter Fuszek; Peter Lakatos; Adam Tabak; Janos Papp; Zsolt Nagy; Istvan Takacs; Henrik Csaba Horvath; Peter Laszlo Lakatos; Gabor Speer

    2004-01-01

    AIM: To examine the calcium metabolism of colorectal cancer(CRC) in patients with colorectal cancer and control patients.METHODS: Seventy newly diagnosed CRC patients were included. The healthy control group was age and gender matched (n=32). Particular attention was devoted to the relationship between serum calcium of patients, and levels of AFP, CEA, carbohydrate antigen 19-9 (CA 19-9) (that could be considered as prognostic factors). Furthermore, the Ca-sensing receptor (CaSR) gene A986S polymorphism was investigated in these patients, as well as the relationship between different CaSR genotypes and the data stated above.RESULTS: A lower level of ionized calcium (also corrected for albumin) was found in the serum of CRC patients with normal 25(OH) vitamin D levels. The ionized calcium concentration was inversely correlated with the serum level of CA 19-9. There was no difference in the distribution of CaSR genotypes, between CRC patients and general population. The genotypes did not correlate with other data examined.CONCLUSION: Based on these results, lower levels of serum calcium might be a pathogenic and prognostic factor in colorectal cancer.

  9. Propriedades e bioatividade de um cimento endodôntico à base de aluminato de cálcio Properties and bioactivity of endodontic calcium aluminate cement

    Directory of Open Access Journals (Sweden)

    I. R. Oliveira

    2011-09-01

    Full Text Available Desde sua introdução na endodontia como um material retro-obturador e selador de defeitos da raiz dental, o agregado de trióxido mineral (MTA tem sido considerado como um material endodôntico revolucionário. Apesar disso, este material apresenta algumas propriedades limitantes, necessitando alterações em sua composição bem como desenvolvimento de novos materiais. Assim, o objetivo desse trabalho foi mostrar a influência de aditivos no desenvolvimento de um cimento endodôntico à base de cimento de aluminato de cálcio (ECAC. Além disso, foram avaliadas as propriedades do ECAC em comparação com o MTA, quando em contato com solução de fluido corporal simulado (SBF. Testes de manipulação e medidas de resistência à compressão, porosidade aparente, tempo de endurecimento, pH e condutividade iônica, foram realizados para os materiais MTA puro e ECAC contendo aditivos. Considerando as propriedades apresentadas pelo ECAC, este material alternativo pode ser indicado para múltiplas aplicações em endodontia.The mineral trioxide aggregate (MTA, a material primarily developed as a root-end filling has been extensively investigated as an innovative product for endodontic applications. However, changes in its formulation/composition involving its mineral aggregates and the development of alternatives of materials have been proposed in an attempt to overcome its negative physical-chemical characteristics. In this work, the influence of additives addition on the development of a novel endodontic cement based on calcium aluminate, has been evaluated. In addition, the properties of endodontic calcium aluminate cement (ECAC were compared with the gold standard mineral-trioxide-aggregate in contact with simulated body fluid (SBF. Manipulation tests and measurements of compressive strength, apparent porosity, setting time, pH and ionic conductivity were carried out on plain MTA and calcium aluminate cement with and without various additives

  10. Multiple template-based image matching using alpha-rooted quaternion phase correlation

    Science.gov (United States)

    DelMarco, Stephen

    2010-04-01

    In computer vision applications, image matching performed on quality-degraded imagery is difficult due to image content distortion and noise effects. State-of-the art keypoint based matchers, such as SURF and SIFT, work very well on clean imagery. However, performance can degrade significantly in the presence of high noise and clutter levels. Noise and clutter cause the formation of false features which can degrade recognition performance. To address this problem, previously we developed an extension to the classical amplitude and phase correlation forms, which provides improved robustness and tolerance to image geometric misalignments and noise. This extension, called Alpha-Rooted Phase Correlation (ARPC), combines Fourier domain-based alpha-rooting enhancement with classical phase correlation. ARPC provides tunable parameters to control the alpha-rooting enhancement. These parameter values can be optimized to tradeoff between high narrow correlation peaks, and more robust wider, but smaller peaks. Previously, we applied ARPC in the radon transform domain for logo image recognition in the presence of rotational image misalignments. In this paper, we extend ARPC to incorporate quaternion Fourier transforms, thereby creating Alpha-Rooted Quaternion Phase Correlation (ARQPC). We apply ARQPC to the logo image recognition problem. We use ARQPC to perform multiple-reference logo template matching by representing multiple same-class reference templates as quaternion-valued images. We generate recognition performance results on publicly-available logo imagery, and compare recognition results to results generated from standard approaches. We show that small deviations in reference templates of sameclass logos can lead to improved recognition performance using the joint matching inherent in ARQPC.

  11. Some practical considerations in finite element-based digital image correlation

    KAUST Repository

    Wang, Bo

    2015-04-20

    As an alternative to subset-based digital image correlation (DIC), finite element-based (FE-based) DIC method has gained increasing attention in the experimental mechanics community. However, the literature survey reveals that some important issues have not been well addressed in the published literatures. This work therefore aims to point out a few important considerations in the practical algorithm implementation of the FE-based DIC method, along with simple but effective solutions that can effectively tackle these issues. First, to better accommodate the possible intensity variations of the deformed images practically occurred in real experiments, a robust zero-mean normalized sum of squared difference criterion, instead of the commonly used sum of squared difference criterion, is introduced to quantify the similarity between reference and deformed elements in FE-based DIC. Second, to reduce the bias error induced by image noise and imperfect intensity interpolation, low-pass filtering of the speckle images with a 5×5 pixels Gaussian filter prior to correlation analysis, is presented. Third, to ensure the iterative calculation of FE-based DIC converges correctly and rapidly, an efficient subset-based DIC method, instead of simple integer-pixel displacement searching, is used to provide accurate initial guess of deformation for each calculation point. Also, the effects of various convergence criteria on the efficiency and accuracy of FE-based DIC are carefully examined, and a proper convergence criterion is recommended. The efficacy of these solutions is verified by numerical and real experiments. The results reveal that the improved FE-based DIC offers evident advantages over existing FE-based DIC method in terms of accuracy and efficiency. © 2015 Elsevier Ltd. All rights reserved.

  12. Electrophysiological correlates of strategic monitoring in event-based and time-based prospective memory.

    Directory of Open Access Journals (Sweden)

    Giorgia Cona

    Full Text Available Prospective memory (PM is the ability to remember to accomplish an action when a particular event occurs (i.e., event-based PM, or at a specific time (i.e., time-based PM while performing an ongoing activity. Strategic Monitoring is one of the basic cognitive functions supporting PM tasks, and involves two mechanisms: a retrieval mode, which consists of maintaining active the intention in memory; and target checking, engaged for verifying the presence of the PM cue in the environment. The present study is aimed at providing the first evidence of event-related potentials (ERPs associated with time-based PM, and at examining differences and commonalities in the ERPs related to Strategic Monitoring mechanisms between event- and time-based PM tasks.The addition of an event-based or a time-based PM task to an ongoing activity led to a similar sustained positive modulation of the ERPs in the ongoing trials, mainly expressed over prefrontal and frontal regions. This modulation might index the retrieval mode mechanism, similarly engaged in the two PM tasks. On the other hand, two further ERP modulations were shown specifically in an event-based PM task. An increased positivity was shown at 400-600 ms post-stimulus over occipital and parietal regions, and might be related to target checking. Moreover, an early modulation at 130-180 ms post-stimulus seems to reflect the recruitment of attentional resources for being ready to respond to the event-based PM cue. This latter modulation suggests the existence of a third mechanism specific for the event-based PM; that is, the "readiness mode".

  13. Calcium, snails, and birds: a case study

    Directory of Open Access Journals (Sweden)

    R. Mänd

    2000-10-01

    Full Text Available Recent studies have shown that wild birds breeding in acidified areas have difficulties with obtaining sufficient calcium for their eggshells, and that the cause of it is the shortage of land snails. Many birds have to search for Ca-rich snail shells on a daily basis during egg production. Molluscs depend on litter calcium, which has decreased due to acidification of the environment. Calcium limitation may be a widespread phenomenon also in non-acidified, naturally Ca-poor areas. The problem is that while in the latter areas the time for development of specific adaptations may have been sufficient, then in acidified areas, on the contrary, calcium shortage is a recent phenomenon. Therefore, since the extent of calcium limitation in non-acidified areas is hard to derive from observational data, experimental approach is needed. We provide experimental evidence that specific calcium deficit does affect reproductive traits also in the birds breeding in naturally base-poor habitats. Our study was conducted in a heterogeneous woodland area in Estonia containing deciduous forest patches as well as base-poor pine forest with low snail abundance. Ca supplementation, using snail shell and chicken eggshell fragments, was carried out for pied flycatchers and great tits. Extra calcium affected positively several reproductive traits like egg volume and eggshell thickness, start of breeding, and fledglings’ parameters. The negative relationship between calcium availability and lay-date suggests that birds adjust their breeding tactics to conditions of Ca deficiency, for example, by postponing laying.

  14. Coupling Effect of Ion Channel Clusters on Calcium Signalling

    International Nuclear Information System (INIS)

    Based on a modified intracellular Ca2+ model involving diffusive coupling of two calcium ion channel clusters, the effects of coupling on calcium signalling are numerically investigated. The simulation results indicate that the diffusive coupling of clusters together with internal noise determine the calcium dynamics of single cluster, and for either homogeneous or heterogeneous coupled clusters, the synchronization of clusters, which is important to calcium signalling, is enhanced by the coupling effect

  15. Coupling Effect of Ion Channel Clusters on Calcium Signalling

    Institute of Scientific and Technical Information of China (English)

    TANG Jun; JIA Ya; YI Ming; MA Jun; YU Guang

    2008-01-01

    @@ Based on a modified intracellular Ca2+ model involving diffusive coupling of two calcium ion channel clusters,the effects of coupling on calcium signalling are numerically investigated.The simulation results indicate that the diffusive coupling of clusters together with internal noise determine the calcium dynamics of single cluster,and for either homogeneous or heterogeneous coupled clusters,the synchronization of clusters,which is important to calcium signalling,is enhanced by the coupling effect.

  16. Scientific Opinion on the safety and efficacy of vitamin C (ascorbic acid, sodium ascorbate, calcium ascorbate, ascorbyl palmitate, sodium calcium ascorbyl phosphate and sodium ascorbyl phosphate as a feed additive for all animal species based on a dossier submitted by DSM Nutritional Products Ltd

    Directory of Open Access Journals (Sweden)

    EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP

    2013-02-01

    Full Text Available Vitamin C is essential for primates, guinea pigs and fish. Vitamin C, in the form of ascorbic acid and its calcium and sodium salts, ascorbyl palmitate, sodium calcium ascorbyl phosphate and sodium ascorbyl phosphate, is safe for all animal species. Setting a maximum content in feed and water for drinking is not considered necessary. Data on the vitamin C consumption of consumers are based on the levels of vitamin C in foodstuffs, including food of animal origin, produced in accordance with current EU legislation on the supplementation of feed with vitamin C. The exposure is far below the guidance level. Any potential contribution of the use of vitamin C in feed is therefore already considered in the above data. Consequently, the use of vitamin C in animal nutrition is not of concern for consumer safety. In the absence of inhalation toxicity studies it would be prudent to assume that inhalation of dust from the additives presents a health hazard to workers. Sodium calcium ascorbyl phosphate is not an irritant to skin and eyes and is unlikely to be a skin sensitiser. This conclusion is extrapolated to sodium ascorbyl phosphate. In the absence of data, ascorbic acid, sodium ascorbate, calcium ascorbate and ascorbyl palmitate should be considered as irritant to skin and eyes and as dermal sensitisers. The supplementation of feed with vitamin C does not pose a risk to the environment. Ascorbic acid, sodium calcium ascorbyl phosphate and sodium ascorbyl phosphate are regarded as effective sources of vitamin C when added to feed or water for drinking. Since ascorbic acid, sodium ascorbate, calcium ascorbate and ascorbyl palmitate are authorised for use as antioxidants in food and their function in feed is essentially the same as that in food, no further demonstration of efficacy is considered necessary.

  17. Adaptive FPGA NoC-based Architecture for Multispectral Image Correlation

    CERN Document Server

    Zhang, Linlin; Fresse, Virginie; Fischer, Viktor

    2009-01-01

    An adaptive FPGA architecture based on the NoC (Network-on-Chip) approach is used for the multispectral image correlation. This architecture must contain several distance algorithms depending on the characteristics of spectral images and the precision of the authentication. The analysis of distance algorithms is required which bases on the algorithmic complexity, result precision, execution time and the adaptability of the implementation. This paper presents the comparison of these distance computation algorithms on one spectral database. The result of a RGB algorithm implementation was discussed.

  18. Double-image encryption based on joint transform correlation and phase-shifting interferometry

    Institute of Scientific and Technical Information of China (English)

    Lina Shen; Jun Li; Hongsen Chang

    2007-01-01

    An image encryption method combining the joint transform correlator (JTC) architecture with phaseshifting interferometry to realize double random-phase encoding is proposed. The encrypted field and the decrypting key are registered as holograms by phase-shifting interferometry. This method can encrypt two images simultaneously to improve the encryption efficiency of the methods based on JTC architecture, and eliminate the system alignment constraint of the methods based on Mach-Zehnder interferometer (MZI)architecture. Its feasibility and validity are verified by computer simulations. Moreover, image encryption and decryption can be achieved at high speed optically or digitally. The encrypted data are suitable for Internet transmission.

  19. Mechanical properties correlation to processing parameters for advanced alumina based refractories

    Directory of Open Access Journals (Sweden)

    Dimitrijević Marija M.

    2012-01-01

    Full Text Available Alumina based refractories are usually used in metallurgical furnaces and their thermal shock resistance is of great importance. In order to improve thermal shock resistance and mechanical properties of alumina based refractories short ceramic fibers were added to the material. SEM technique was used to compare the microstructure of specimens and the observed images gave the porosity and morphological characteristics of pores in the specimens. Standard compression test was used to determine the modulus of elasticity and compression strength. Results obtained from thermal shock testing and mechanical properties measurements were used to establish regression models that correlated specimen properties to process parameters.

  20. Effect of dietary calcium and phosphorus on intestinal calcium absorption and vitamin D metabolism

    International Nuclear Information System (INIS)

    To understand better dietary regulation of intestinal calcium absorption, a quantitative assessment of the metabolites in plasma and duodenum of rats given daily doses of radioactive vitamin D3 and diets differing in calcium and phosphorus content was made. All known vitamin D metabolites were ultimately identified by high-pressure liquid chromatography. In addition to the known metabolites (25-hydroxyvitamin D3, 24,25-dihydroxyvitamin D3, 1,25-dihydroxyvitamin D3, 25,26-dihydroxyvitamin D3, and 1,24,25-trihydroxyvitamin D3), several new and unidentified metabolites were found. In addition to 1,25-dihydroxyvitamin D3 and 1,24,25-trihydroxyvitamin D3, the levels of some of the unknown metabolites could be correlated with intestinal calcium transport. However, whether or not any of these metabolites plays a role in the stimulation of intestinal calcium absorption by low dietary calcium or low dietary phosphorus remains unknown

  1. Development of a new proximate analysis based correlation to predict calorific value of coal

    Energy Technology Data Exchange (ETDEWEB)

    A.K. Majumder; Rachana Jain; P. Banerjee; J.P. Barnwal [Advanced Materials and Processes Research Institute (CSIR), Bhopal (India). Department of Mineral Engineering

    2008-10-15

    The experimental determination of higher heating value (HHV) of solid fuels is a cost intensive process, as it requires special instrumentation and highly trained analyst to operate it, where as proximate analysis data can be obtained relatively easily using an ordinary muffle furnace. Therefore, to simplify the task and to reduce the cost of analysis many correlations were developed for determining HHV from proximate analysis of solid fuels. An attempt has been made in this paper to evaluate the applicability of these correlations with a special focus on Indian coals. It has been observed that the developed correlations are either complex in nature or by-pass the effect of important variables like moisture and ash contents of coals. An effort has, therefore, been made to develop a simple correlation based on proximate analysis data for predicting HHV of coal (as-received basis). The model presented here is developed using analyses of 250 coal samples and its significance lies in involvement of all the major variables affecting the HHV. The developed model appears to be better than the existing models. 10 refs., 4 figs., 2 tabs.

  2. Research on computer tracking system of uniaxial tension based on image correlation method

    Science.gov (United States)

    Wang, Wei; He, Xiao-yuan

    2011-08-01

    The mechanics properties of the materials in which displacement sensors or strain gauges can not be intalled or pasted are unable to be measured by the experiment of traditional tension. In view of the case, the new computer tracking system of uniaxial tension based on the digital image correlation method has been developed. Firstly, according to the principle of uniaxial tension, the computer tracking system is designed by combining the loading installation, light source, camera lens, image card with the computer. Secondly, the correlativity is high between the original image and the deformed image, the image correlation formula is utilized to calculate the correlation coefficients of pixel values between the object template and the search region. Moreover, the measurement precision can be improved greatly by using the algorithm of bilinear inter value. Finally, through the computer tracking experiment of uniaxial tension of the rubber band, the object template size of 11× 7 and the search region of 21 × 17 are used to improve the computer calculating speed in the matching processing. The experimental results show that the object can be successfully tracked and the deformation evoluation of the rubber band are agree with the actual mechanics properties of materials.

  3. a Novel Sub-Pixel Matching Algorithm Based on Phase Correlation Using Peak Calculation

    Science.gov (United States)

    Xie, Junfeng; Mo, Fan; Yang, Chao; Li, Pin; Tian, Shiqiang

    2016-06-01

    The matching accuracy of homonymy points of stereo images is a key point in the development of photogrammetry, which influences the geometrical accuracy of the image products. This paper presents a novel sub-pixel matching method phase correlation using peak calculation to improve the matching accuracy. The peak theoretic centre that means to sub-pixel deviation can be acquired by Peak Calculation (PC) according to inherent geometrical relationship, which is generated by inverse normalized cross-power spectrum, and the mismatching points are rejected by two strategies: window constraint, which is designed by matching window and geometric constraint, and correlation coefficient, which is effective for satellite images used for mismatching points removing. After above, a lot of high-precise homonymy points can be left. Lastly, three experiments are taken to verify the accuracy and efficiency of the presented method. Excellent results show that the presented method is better than traditional phase correlation matching methods based on surface fitting in these aspects of accuracy and efficiency, and the accuracy of the proposed phase correlation matching algorithm can reach 0.1 pixel with a higher calculation efficiency.

  4. [Correlation analysis of regional vegetation seasonal fluctuation and climate factors based on MODIS-EVI].

    Science.gov (United States)

    Peng, Dai-liang; Huang, Jing-feng; Wang, Xiu-zhen

    2007-05-01

    Taking Zhejiang Province as study area, and based on the data of MODIS-EVI, daily mean air temperature and daily precipitation from 52 weather stations, and actual land use in 2001-2004, the time lag cross-correlation analysis was made to relate the seasonal fluctuations of enhanced vegetation index (EVI) of farmland, woodland and garden plot with air temperature and precipitation. The results indicated that in most areas of Zhejiang, EVI had no time lag to air temperature, but about one month lag to precipitation. The time that air temperature or precipitation significantly influenced the seasonal fluctuation of most areas EVI lasted about 50 days. The correlation coefficients of the EVI of farmland, woodland and garden plot with air temperature and precipitation differed with time lags. When the time lag was zero, the correlation coefficient decreased in the sequence of woodland > garden plot > farmland, and when the time lag was not zero, it changed in adverse. The EVI of these three land-use types all had stronger correlation with air temperature than with precipitation, indicating that air temperature had more influence on the seasonal fluctuation of EVI. PMID:17650845

  5. Brain correlates of pro-social personality traits: a voxel-based morphometry study.

    Science.gov (United States)

    Coutinho, Joana F; Sampaio, Adriana; Ferreira, Miguel; Soares, José M; Gonçalves, Oscar F

    2013-09-01

    Of the five personality dimensions described by the Big Five Personality Model (Costa and McCrae 1992), Extraversion and Agreeableness are the traits most commonly associated with a pro-social orientation. In this study we tested whether a pro-social orientation, as expressed in terms of Extraversion and Agreeableness, is associated with a specific grey matter phenotype. Fifty-two healthy participants underwent magnetic resonance imaging (MRI) and completed the NEO-Five Factor Inventory (NEO-FFI), a self-report measure of the Big Five personality traits. Voxel-based morphometry (VBM) was used to investigate the correlation between brain structure and the personality traits of Agreeableness and Extraversion. We found that Extraversion was negatively correlated with grey matter density in the middle frontal and orbitofrontal gyri while Agreeableness was negatively correlated with grey matter density in the inferior parietal, middle occipital and posterior cingulate gyri. No positive correlations were found. These results suggest that pro-social personality traits seem to be associated with decreases in grey matter density in more frontal regions for Extraversion, and more posterior regions for Agreeableness. PMID:23512407

  6. Quantification of ultrasound correlation-based flow velocity mapping and edge velocity gradient measurement.

    Science.gov (United States)

    Park, Dae Woo; Kruger, Grant H; Rubin, Jonathan M; Hamilton, James; Gottschalk, Paul; Dodde, Robert E; Shih, Albert J; Weitzel, William F

    2013-10-01

    This study investigated the use of ultrasound speckle decorrelation- and correlation-based lateral speckle-tracking methods for transverse and longitudinal blood velocity profile measurement, respectively. By studying the blood velocity gradient at the vessel wall, vascular wall shear stress, which is important in vascular physiology as well as the pathophysiologic mechanisms of vascular diseases, can be obtained. Decorrelation-based blood velocity profile measurement transverse to the flow direction is a novel approach, which provides advantages for vascular wall shear stress measurement over longitudinal blood velocity measurement methods. Blood flow velocity profiles are obtained from measurements of frame-to-frame decorrelation. In this research, both decorrelation and lateral speckle-tracking flow estimation methods were compared with Poiseuille theory over physiologic flows ranging from 50 to 1000 mm/s. The decorrelation flow velocity measurement method demonstrated more accurate prediction of the flow velocity gradient at the wall edge than the correlation-based lateral speckle-tracking method. The novelty of this study is that speckle decorrelation-based flow velocity measurements determine the blood velocity across a vessel. In addition, speckle decorrelation-based flow velocity measurements have higher axial spatial resolution than Doppler ultrasound measurements to enable more accurate measurement of blood velocity near a vessel wall and determine the physiologically important wall shear.

  7. Smoking, calcium, calcium antagonists, and aging.

    Science.gov (United States)

    Nicita-Mauro, V

    1990-01-01

    Aging is characterized, besides other changes, by a progressive increase in calcium content in the arterial wall, which is enhanced by diabetes mellitus, osteoporosis, arterial hypertension, and tabagism. As to tabagism, experiments in animals have shown that nicotine can increase calcium content of the arterial wall, and clinical studies have demonstrated that cigarette smoking induces peripheral vasoconstriction, with consequent increase in blood pressure levels. In order to study the role of calcium ions in the pathogenesis of the vasoconstrictive lesions caused by "acute" smoking, the author has studied the peripheral vascular effects of the calcium-channel antagonist nifedipine, a dihydropyridine derivative, and calcitonin, a hypocalcemizing hormone which possess vasoactive actions on 12 elderly regular smokers (mean age 65.8 years). The results demonstrated that both nifedipine (10 mg sublingually 20 min before smoking) and salmon calcitonin (100 MRC U/daily intramuscularly for three days) are able to prevent peripheral vasoconstriction evaluated by Doppler velocimetry, as well as the increase of blood pressure induced by smoking. On the basis of our results, the author proposes that cigarette smoking-induced vasoconstriction is a calcium-mediated process, which can be hindered by drugs with calcium antagonist action. PMID:2226675

  8. Analysis on Calcium Based Sulphur- fixation Reagent hydration Active%钙基固硫剂水合活性分析

    Institute of Scientific and Technical Information of China (English)

    于德亭; 于荣华; 侯栋岐; 侯清濯; 陈昌和

    2000-01-01

    基于Ca0水合放热,设计专用试验装置对生石灰水合活性进行测试比较,其结果对炉内喷钙增湿水合烟气脱硫和以生石灰为吸着剂的简易湿法脱硫技术吸着剂选择有指导意义。%Based on CaO dydration exothennity, the special test unit is designed to measure and compare the quick lime hydration actives, the conclusion which is useful for the adsorbent selection of interior furnace Calcium spary moisture increase hydration gas desulphuring technique and the quick lime adsorbent simple wet desulphuring techwique is achieved.

  9. Calcium absorption and achlorhydria

    International Nuclear Information System (INIS)

    Defective absorption of calcium has been thought to exist in patients with achlorhydria. The author compared absorption of calcium in its carbonate form with that in a pH-adjusted citrate form in a group of 11 fasting patients with achlorhydria and in 9 fasting normal subjects. Fractional calcium absorption was measured by a modified double-isotope procedure with 0.25 g of calcium used as the carrier. Mean calcium absorption (+/- S.D.) in the patients with achlorhydria was 0.452 +/- 0.125 for citrate and 0.042 +/- 0.021 for carbonate (P less than 0.0001). Fractional calcium absorption in the normal subjects was 0.243 +/- 0.049 for citrate and 0.225 +/- 0.108 for carbonate (not significant). Absorption of calcium from carbonate in patients with achlorhydria was significantly lower than in the normal subjects and was lower than absorption from citrate in either group; absorption from citrate in those with achlorhydria was significantly higher than in the normal subjects, as well as higher than absorption from carbonate in either group. Administration of calcium carbonate as part of a normal breakfast resulted in completely normal absorption in the achlorhydric subjects. These results indicate that calcium absorption from carbonate is impaired in achlorhydria under fasting conditions. Since achlorhydria is common in older persons, calcium carbonate may not be the ideal dietary supplement

  10. Structures of apicomplexan calcium-dependent protein kinases reveal mechanism of activation by calcium

    Energy Technology Data Exchange (ETDEWEB)

    Wernimont, Amy K; Artz, Jennifer D.; Jr, Patrick Finerty; Lin, Yu-Hui; Amani, Mehrnaz; Allali-Hassani, Abdellah; Senisterra, Guillermo; Vedadi, Masoud; Tempel, Wolfram; Mackenzie, Farrell; Chau, Irene; Lourido, Sebastian; Sibley, L. David; Hui, Raymond (Toronto); (WU-MED)

    2010-09-21

    Calcium-dependent protein kinases (CDPKs) have pivotal roles in the calcium-signaling pathway in plants, ciliates and apicomplexan parasites and comprise a calmodulin-dependent kinase (CaMK)-like kinase domain regulated by a calcium-binding domain in the C terminus. To understand this intramolecular mechanism of activation, we solved the structures of the autoinhibited (apo) and activated (calcium-bound) conformations of CDPKs from the apicomplexan parasites Toxoplasma gondii and Cryptosporidium parvum. In the apo form, the C-terminal CDPK activation domain (CAD) resembles a calmodulin protein with an unexpected long helix in the N terminus that inhibits the kinase domain in the same manner as CaMKII. Calcium binding triggers the reorganization of the CAD into a highly intricate fold, leading to its relocation around the base of the kinase domain to a site remote from the substrate binding site. This large conformational change constitutes a distinct mechanism in calcium signal-transduction pathways.

  11. [The correlation based mid-infrared temperature and emissivity separation algorithm].

    Science.gov (United States)

    Cheng, Jie; Nie, Ai-Xiu; Du, Yong-Ming

    2009-02-01

    Temperature and emissivity separation is the key problem in infrared remote sensing. Based on the analysis of the relationship between the atmospheric downward radiance and surface emissivity containing atmosphere residue without the effects of sun irradiation, the present paper puts forward a temperature and emissivity separation algorithm for the ground-based mid-infrared hyperspectral data. The algorithm uses the correlation between the atmospheric downward radiance and surface emissivity containing atmosphere residue as a criterion to optimize the surface temperature, and the correlation between the atmospheric downward radiance and surface emissivity containing atmosphere residue depends on the bias between the estimated surface temperature and true surface temperature. The larger the temperature bias, the greater the correlation. Once we have obtained the surface temperature, the surface emissivity can be calculated easily. The accuracy of the algorithm was evaluated with the simulated mid-infrared hyperspectral data. The results of simulated calculation show that the algorithm can achieve higher accuracy of temperature and emissivity inversion, and also has broad applicability. Meanwhile, the algorithm is insensitive to the instrumental random noise and the change in atmospheric downward radiance during the field measurements.

  12. Boundary-layer transition prediction using a simplified correlation-based model

    Institute of Scientific and Technical Information of China (English)

    Xia Chenchao; Chen Weifang

    2016-01-01

    This paper describes a simplified transition model based on the recently developed correlation-based c ? Reht transition model. The transport equation of transition momentum thick-ness Reynolds number is eliminated for simplicity, and new transition length function and critical Reynolds number correlation are proposed. The new model is implemented into an in-house com-putational fluid dynamics (CFD) code and validated for low and high-speed flow cases, including the zero pressure flat plate, airfoils, hypersonic flat plate and double wedge. Comparisons between the simulation results and experimental data show that the boundary-layer transition phenomena can be reasonably illustrated by the new model, which gives rise to significant improvements over the fully laminar and fully turbulent results. Moreover, the new model has comparable features of accuracy and applicability when compared with the original c ? Reht model. In the meantime, the newly proposed model takes only one transport equation of intermittency factor and requires fewer correlations, which simplifies the original model greatly. Further studies, especially on separation-induced transition flows, are required for the improvement of the new model.

  13. [The correlation based mid-infrared temperature and emissivity separation algorithm].

    Science.gov (United States)

    Cheng, Jie; Nie, Ai-Xiu; Du, Yong-Ming

    2009-02-01

    Temperature and emissivity separation is the key problem in infrared remote sensing. Based on the analysis of the relationship between the atmospheric downward radiance and surface emissivity containing atmosphere residue without the effects of sun irradiation, the present paper puts forward a temperature and emissivity separation algorithm for the ground-based mid-infrared hyperspectral data. The algorithm uses the correlation between the atmospheric downward radiance and surface emissivity containing atmosphere residue as a criterion to optimize the surface temperature, and the correlation between the atmospheric downward radiance and surface emissivity containing atmosphere residue depends on the bias between the estimated surface temperature and true surface temperature. The larger the temperature bias, the greater the correlation. Once we have obtained the surface temperature, the surface emissivity can be calculated easily. The accuracy of the algorithm was evaluated with the simulated mid-infrared hyperspectral data. The results of simulated calculation show that the algorithm can achieve higher accuracy of temperature and emissivity inversion, and also has broad applicability. Meanwhile, the algorithm is insensitive to the instrumental random noise and the change in atmospheric downward radiance during the field measurements. PMID:19445199

  14. Evaporation Behavior of Phosphorus from Metallurgical Grade Silicon via Calcium-Based Slag Treatment and Hydrochloric Acid Leaching

    Science.gov (United States)

    Huang, Liuqing; Lai, Huixian; Lu, Chenghao; Fang, Ming; Ma, Wenhui; Xing, Pengfei; Luo, Xuetao; Li, Jintang

    2016-01-01

    Phosphorus removal from metallurgical grade silicon by CaO-SiO2-CaCl2 slag treatment, HCl leaching, and vacuum refining was investigated. The effect of different compositions of slag was evaluated. The calcium concentration in slag-treated silicon increased with increasing CaO/SiO2 mass ratio of slag, decreasing the evaporation efficiency of phosphorus in molten silicon. The total phosphorus removal efficiency changed from 93.0% to 98.3% when the slag-treated silicon was treated with HCl before vacuum refining. The final concentration of phosphorus in silicon was 0.43 ppmw. This is because phosphorus was removed from metallurgical-grade silicon as follows: Phosphorus reacts with slag at the silicon/slag interface and forms Ca3(PO4)2 and Ca3P2, most of which diffuse from the interface to the slag phase. The remaining Ca3(PO4)2 and Ca3P2 reduce the phosphorus removal efficiency by altering the activity coefficient of phosphorus in molten silicon. HCl leaching enhanced the phosphorus removal efficiency by removing the remaining Ca3(PO4)2 and Ca3P2. Therefore, the mass transfer of phosphorus from metallurgical-grade silicon was accelerated.

  15. Comparison and preparation of multilayered polylactic acid fabric strengthen calcium phosphate-based bone substitutes for orthopedic applications.

    Science.gov (United States)

    Chen, Wen-Cheng; Ko, Chia-Ling; Yang, Jia-Kai; Wu, Hui-Yu; Lin, Jia-Horng

    2016-03-01

    An attempt to maintain the three-dimensional space into restorative sites through the conveniently pack porous fillers are general used strategy. Advancement in the manufacturing protective shells in the scaffolds, which would be filled with brittle ceramic grafts for the development of highly connective pores provides the approach to solve crack problem for generating the tissues. Therefore, multilayered braided and alkalized poly(lactic acid) (PLA) composites with calcium phosphate bone cement (CPC) were synthesized and compared. The PLA/CPC composites were divided into various groups according to a series of heat-treatment temperatures (100-190 °C) and periods (1-3 h) and then characterized. The effects of 24-h immersion on the strength decay resistance of the samples were compared. Results showed that the residual oil capped on the surfaces of alkalized PLA braid was removed, and the structure was unaltered. However, the reduced tensile stress of alkalized PLA braids was due to ester-group formation by hydrolysis. Mechanical test results of PLA/CPC composites showed that the strength significantly increased after heat treatment, except when the heating temperature was higher than the PLA melting point at approximately 160-170 °C. The degree of PLA after recrystallization became higher than that of unheated composites, thereby leading to reduced strength and toughness of the specimen. Braiding fibers of biodegradable PLA reinforced and toughened the structure particularly of the extra-brittle material of thin-sheet CPC after implantation.

  16. Correlates of Protection for M Protein-Based Vaccines against Group A Streptococcus

    Directory of Open Access Journals (Sweden)

    Shu Ki Tsoi

    2015-01-01

    Full Text Available Group A streptococcus (GAS is known to cause a broad spectrum of illness, from pharyngitis and impetigo, to autoimmune sequelae such as rheumatic heart disease, and invasive diseases. It is a significant cause of infectious disease morbidity and mortality worldwide, but no efficacious vaccine is currently available. Progress in GAS vaccine development has been hindered by a number of obstacles, including a lack of standardization in immunoassays and the need to define human correlates of protection. In this review, we have examined the current immunoassays used in both GAS and other organisms, and explored the various challenges in their implementation in order to propose potential future directions to identify a correlate of protection and facilitate the development of M protein-based vaccines, which are currently the main GAS vaccine candidates.

  17. Improved decryption quality and security of a joint transform correlator-based encryption system

    Science.gov (United States)

    Vilardy, Juan M.; Millán, María S.; Pérez-Cabré, Elisabet

    2013-02-01

    Some image encryption systems based on modified double random phase encoding and joint transform correlator architecture produce low quality decrypted images and are vulnerable to a variety of attacks. In this work, we analyse the algorithm of some reported methods that optically implement the double random phase encryption in a joint transform correlator. We show that it is possible to significantly improve the quality of the decrypted image by introducing a simple nonlinear operation in the encrypted function that contains the joint power spectrum. This nonlinearity also makes the system more resistant to chosen-plaintext attacks. We additionally explore the system resistance against this type of attack when a variety of probability density functions are used to generate the two random phase masks of the encryption-decryption process. Numerical results are presented and discussed.

  18. Novel Point-to-Point Scan Matching Algorithm Based on Cross-Correlation

    Directory of Open Access Journals (Sweden)

    Jaromir Konecny

    2016-01-01

    Full Text Available The localization of mobile robots in outdoor and indoor environments is a complex issue. Many sophisticated approaches, based on various types of sensory inputs and different computational concepts, are used to accomplish this task. However, many of the most efficient methods for mobile robot localization suffer from high computational costs and/or the need for high resolution sensory inputs. Scan cross-correlation is a traditional approach that can be, in special cases, used to match temporally aligned scans of robot environment. This work proposes a set of novel modifications to the cross-correlation method that extend its capability beyond these special cases to general scan matching and mitigate its computational costs so that it is usable in practical settings. The properties and validity of the proposed approach are in this study illustrated on a number of computational experiments.

  19. A Novel Three-Head Ultrasonic System for Distance Measurements Based on the Correlation Method

    Directory of Open Access Journals (Sweden)

    Gądek Krzysztof

    2014-12-01

    Full Text Available A novel double-emitter ultrasonic system for distance measurements based on the correlation method is presented. The proposed distance measurement method may be particularly useful in difficult conditions, e.g. for media parameters undergoing fast changes or in cases when obstacles and mechanical interference produce false reflections. The system is a development of a previously studied single-head idea. The present article covers a comparison of the two systems in terms of efficiency and precision. Experimental research described in this paper indicated that adding the second head improved the measurement exactness – standard deviation decreased by 40%. The correlation method is also described in detail, also giving the criterion for the quality of the measurement signal.

  20. NMR spectroscopy, Hammett correlations and biological activity of some Schiff bases derived from piperonal

    Energy Technology Data Exchange (ETDEWEB)

    Echevarria, Aurea [Universidade Federal Rural do Rio de Janeiro, Itaguai, RJ (Brazil). Dept. de Quimica; Nascimento, Maria da Graca; Geronimo, Vanilde [Santa Catarina Univ., Florianopolis, SC (Brazil). Dept. de Quimica; Miller, Joseph [Paraiba Univ., Joao Pessoa, PB (Brazil); Giesbrecht, Astrea [Sao Paulo Univ., SP (Brazil). Inst. de Ciencias Biomedicas

    1999-07-01

    A series of eleven Schiff Bases have been synthesized. They were obtained by condensation of piperonal (3,4-methylenedioxybenzaldehyde) with the corresponding aromatic primary amines. Their {sup 1}H and {sup 13}C-NMR spectra have been obtained and the Hammett correlations including chemical shifts and the substituent constants ({sigma}{sub p}, {sigma}R e {sigma}I) were studied. Linear and bilinear significant correlations were observed for iminic carbon (C-{alpha}) and C-1{sup '}, showing a more significant resonance effect on chemical shifts. The chemical shifts for C-4{sup '} were highly affected by substituent effects, especially for halogens in the expected direction. Their biological activity against microorganisms has also been measured and significant activity was showed against Epidermophyton floccosum. The biological activity did not give a reasonable relationship with electronic effects. (author)

  1. NMR spectroscopy, Hammett correlations and biological activity of some Schiff bases derived from piperonal

    International Nuclear Information System (INIS)

    A series of eleven Schiff Bases have been synthesized. They were obtained by condensation of piperonal (3,4-methylenedioxybenzaldehyde) with the corresponding aromatic primary amines. Their 1H and 13C-NMR spectra have been obtained and the Hammett correlations including chemical shifts and the substituent constants (σp, σR e σI) were studied. Linear and bilinear significant correlations were observed for iminic carbon (C-α) and C-1', showing a more significant resonance effect on chemical shifts. The chemical shifts for C-4' were highly affected by substituent effects, especially for halogens in the expected direction. Their biological activity against microorganisms has also been measured and significant activity was showed against Epidermophyton floccosum. The biological activity did not give a reasonable relationship with electronic effects. (author)

  2. Effects of correlated parameters and uncertainty in electronic-structure-based chemical kinetic modelling

    Science.gov (United States)

    Sutton, Jonathan E.; Guo, Wei; Katsoulakis, Markos A.; Vlachos, Dionisios G.

    2016-04-01

    Kinetic models based on first principles are becoming common place in heterogeneous catalysis because of their ability to interpret experimental data, identify the rate-controlling step, guide experiments and predict novel materials. To overcome the tremendous computational cost of estimating parameters of complex networks on metal catalysts, approximate quantum mechanical calculations are employed that render models potentially inaccurate. Here, by introducing correlative global sensitivity analysis and uncertainty quantification, we show that neglecting correlations in the energies of species and reactions can lead to an incorrect identification of influential parameters and key reaction intermediates and reactions. We rationalize why models often underpredict reaction rates and show that, despite the uncertainty being large, the method can, in conjunction with experimental data, identify influential missing reaction pathways and provide insights into the catalyst active site and the kinetic reliability of a model. The method is demonstrated in ethanol steam reforming for hydrogen production for fuel cells.

  3. A GPU-based Correlator X-engine Implemented on the CHIME Pathfinder

    CERN Document Server

    Denman, Nolan; Bandura, Kevin; Connor, Liam; Dobbs, Matt; Fandino, Mateus; Halpern, Mark; Hincks, Adam; Hinshaw, Gary; Höfer, Carolin; Klages, Peter; Masui, Kiyoshi; Parra, Juan Mena; Newburgh, Laura; Recnik, Andre; Shaw, Richard; Sigurdson, Kris; Smith, Kendrick; Vanderlinde, Keith

    2015-01-01

    We present the design and implementation of a custom GPU-based compute cluster that provides the correlation X-engine of the CHIME Pathfinder radio telescope. It is among the largest such systems in operation, correlating 32,896 baselines (256 inputs) over 400MHz of radio bandwidth. Making heavy use of consumer-grade parts and a custom software stack, the system was developed at a small fraction of the cost of comparable installations. Unlike existing GPU backends, this system is built around OpenCL kernels running on consumer-level AMD GPUs, taking advantage of low-cost hardware and leveraging packed integer operations to double algorithmic efficiency. The system achieves the required 105TOPS in a 10kW power envelope, making it among the most power-efficient X-engines in use today.

  4. A Modified Radiosurgery-Based Arteriovenous Malformation Grading Scale and Its Correlation With Outcomes

    International Nuclear Information System (INIS)

    Purpose: The Pittsburgh radiosurgery-based arteriovenous malformation (AVM) grading scale was developed to predict patient outcomes after radiosurgery and was later modified with location as a two-tiered variable (deep vs. other). The purpose of this study was to test the modified radiosurgery-based AVM score in a separate set of AVM patients managed with radiosurgery. Methods and Materials: The AVM score is calculated as follows: AVM score = (0.1)(volume, cc) + (0.02)(age, years) + (0.5)(location; frontal/temporal/parietal/occipital/intraventricular/corpus callosum/cerebellar = 0, basal ganglia/thalamus/brainstem = 1). Testing of the modified system was performed on 293 patients having AVM radiosurgery from 1992 to 2004 at the University of Pittsburgh with dose planning based on a combination of stereotactic angiography and MRI. The median patient age was 38 years, the median AVM volume was 3.3 cc, and 57 patients (19%) had deep AVMs. The median modified AVM score was 1.25. The median patient follow-up was 39 months. Results: The modified AVM scale correlated with the percentage of patients with AVM obliteration without new deficits (≤1.00, 62%; 1.01-1.50, 51%; 1.51-2.00, 53%; and >2.00, 32%; F = 11.002, R2 = 0.8117, p = 0.001). Linear regression also showed a statistically significant correlation between outcome and dose prescribed to the margin (F = 25.815, p <0.001). Conclusions: The modified radiosurgery-based AVM grading scale using location as a two-tiered variable correlated with outcomes when tested on a cohort of patients who underwent both angiography and MRI for dose planning. This system can be used to guide choices among observation, endovascular, surgical, and radiosurgical management strategies for individual AVM patients.

  5. Stochastic models of intracellular calcium signals

    International Nuclear Information System (INIS)

    Cellular signaling operates in a noisy environment shaped by low molecular concentrations and cellular heterogeneity. For calcium release through intracellular channels–one of the most important cellular signaling mechanisms–feedback by liberated calcium endows fluctuations with critical functions in signal generation and formation. In this review it is first described, under which general conditions the environment makes stochasticity relevant, and which conditions allow approximating or deterministic equations. This analysis provides a framework, in which one can deduce an efficient hybrid description combining stochastic and deterministic evolution laws. Within the hybrid approach, Markov chains model gating of channels, while the concentrations of calcium and calcium binding molecules (buffers) are described by reaction–diffusion equations. The article further focuses on the spatial representation of subcellular calcium domains related to intracellular calcium channels. It presents analysis for single channels and clusters of channels and reviews the effects of buffers on the calcium release. For clustered channels, we discuss the application and validity of coarse-graining as well as approaches based on continuous gating variables (Fokker–Planck and chemical Langevin equations). Comparison with recent experiments substantiates the stochastic and spatial approach, identifies minimal requirements for a realistic modeling, and facilitates an understanding of collective channel behavior. At the end of the review, implications of stochastic and local modeling for the generation and properties of cell-wide release and the integration of calcium dynamics into cellular signaling models are discussed

  6. Stochastic models of intracellular calcium signals

    Energy Technology Data Exchange (ETDEWEB)

    Rüdiger, Sten, E-mail: sten.ruediger@physik.hu-berlin.de

    2014-01-10

    Cellular signaling operates in a noisy environment shaped by low molecular concentrations and cellular heterogeneity. For calcium release through intracellular channels–one of the most important cellular signaling mechanisms–feedback by liberated calcium endows fluctuations with critical functions in signal generation and formation. In this review it is first described, under which general conditions the environment makes stochasticity relevant, and which conditions allow approximating or deterministic equations. This analysis provides a framework, in which one can deduce an efficient hybrid description combining stochastic and deterministic evolution laws. Within the hybrid approach, Markov chains model gating of channels, while the concentrations of calcium and calcium binding molecules (buffers) are described by reaction–diffusion equations. The article further focuses on the spatial representation of subcellular calcium domains related to intracellular calcium channels. It presents analysis for single channels and clusters of channels and reviews the effects of buffers on the calcium release. For clustered channels, we discuss the application and validity of coarse-graining as well as approaches based on continuous gating variables (Fokker–Planck and chemical Langevin equations). Comparison with recent experiments substantiates the stochastic and spatial approach, identifies minimal requirements for a realistic modeling, and facilitates an understanding of collective channel behavior. At the end of the review, implications of stochastic and local modeling for the generation and properties of cell-wide release and the integration of calcium dynamics into cellular signaling models are discussed.

  7. High-Precise and Robust Face-Recognition System Based on Optical Parallel Correlator

    Science.gov (United States)

    Kodate, Kashiko

    2005-10-01

    Facial recognition is applied in a wide range of security systems, and has been studied since the 1970s, with extensive research into and development of digital processing. However, there is only available a 1:1 verification system combined with ID card identification, or an ID-less system with a small number of images in the database. The number of images that can be stored is limited, and recognition has to be improved to account for photos taken at different angles. Commercially available facial recognition systems for the most part utilize digital computers performing electronic pattern recognition. In contrast, optical analog operations can process two-dimensional images instantaneously in parallel using a lens-based Fourier transform function. In the 1960s two methods were proposed, the Vanderlugt correlator and the joint transform correlator (JTC). We present a new scheme using a multi-channel parallel JTC to make better use of spatial parallelism, through the use of a diffraction-type multi-level zone-plate array to extend a single-channel JTC. Our project's objectives were: (i) to design a matched filter which equips the system with high recognition capability at a faster calculation speed by analyzing the spatial frequency of facial image elements, and (ii) to create a four-channel Vanderlugt correlator with super-high-speed (1000 frame/s) optical parallel facial recognition system, robust enough for 1:N identification, for a large database with 4000 images. Automation was also achieved for the entire process via a practical controlling system. The achieved super-high-speed facial recognition system based on optical parallelism is faster in its processing time than the JTC optical correlator.

  8. An image based information system - Architecture for correlating satellite and topological data bases

    Science.gov (United States)

    Bryant, N. A.; Zobrist, A. L.

    1978-01-01

    The paper describes the development of an image based information system and its use to process a Landsat thematic map showing land use or land cover in conjunction with a census tract polygon file to produce a tabulation of land use acreages per census tract. The system permits the efficient cross-tabulation of two or more geo-coded data sets, thereby setting the stage for the practical implementation of models of diffusion processes or cellular transformation. Characteristics of geographic information systems are considered, and functional requirements, such as data management, geocoding, image data management, and data analysis are discussed. The system is described, and the potentialities of its use are examined.

  9. Code Synchronization Algorithm Based on Segment Correlation in Spread Spectrum Communication

    Directory of Open Access Journals (Sweden)

    Aohan Li

    2015-10-01

    Full Text Available Spread Spectrum (SPSP Communication is the theoretical basis of Direct Sequence Spread Spectrum (DSSS transceiver technology. Spreading code, modulation, demodulation, carrier synchronization and code synchronization in SPSP communications are the core parts of DSSS transceivers. This paper focuses on the code synchronization problem in SPSP communications. A novel code synchronization algorithm based on segment correlation is proposed. The proposed algorithm can effectively deal with the informational misjudgment caused by the unreasonable data acquisition times. This misjudgment may lead to an inability of DSSS receivers to restore transmitted signals. Simulation results show the feasibility of a DSSS transceiver design based on the proposed code synchronization algorithm. Finally, the communication functions of the DSSS transceiver based on the proposed code synchronization algorithm are implemented on Field Programmable Gate Array (FPGA.

  10. Measurements of intracellular calcium

    International Nuclear Information System (INIS)

    Intracellular calcium concentration ([Ca2+]i) has been measured in cultured cells by using Fura-2 load cells and a computer-controlled Perkin Elmer LS-5B spectrofluorometer. Increased [Ca2+]i in cells exposed to extracellular bilirubin was observed both with and without extracellular calcium. However, the increase was considerable larger with extracellular calcium. The enhancement of [Ca2+]i became smaller with decreasing bilirubin/BSA (bovine serum albumine) ratio. 5 refs., 5 figs

  11. Incorporating benthic community changes into hydrochemical-based projections of coral reef calcium carbonate production under ocean acidification

    Science.gov (United States)

    Shaw, Emily C.; Hamylton, Sarah M.; Phinn, Stuart R.

    2016-06-01

    The existence of coral reefs is dependent on the production and maintenance of calcium carbonate (CaCO3) framework that is produced through calcification. The net production of CaCO3 will likely decline in the future, from both declining net calcification rates (decreasing calcification and increasing dissolution) and shifts in benthic community composition from calcifying organisms to non-calcifying organisms. Here, we present a framework for hydrochemical studies that allows both declining net calcification rates and changes in benthic community composition to be incorporated into projections of coral reef CaCO3 production. The framework involves upscaling net calcification rates for each benthic community type using mapped proportional cover of the benthic communities. This upscaling process was applied to the reef flats at One Tree and Lady Elliot reefs (Great Barrier Reef) and Shiraho Reef (Okinawa), and compared to existing data. Future CaCO3 budgets were projected for Lady Elliot Reef, predicting a decline of 53 % from the present value by end-century (800 ppm CO2) without any changes to benthic community composition. A further 5.7 % decline in net CaCO3 production is expected for each 10 % decline in calcifier cover, and net dissolution is predicted by end-century if calcifier cover drops below 18 % of the present extent. These results show the combined negative effect of both declining net calcification rates and changing benthic community composition on reefs and the importance of considering both processes for determining future reef CaCO3 production.

  12. NIR fluorescence spectroscopic investigations of Er{sup 3+}-ions doped borate based tellurium calcium zinc niobium oxide glasses

    Energy Technology Data Exchange (ETDEWEB)

    Ravi, O. [Department of Instrumentation, Sri Venkateswara University, Tirupati 517502 (India); Dhoble, S.J. [Department of Physics, RTM Nagpur University, Nagpur 440033 (India); Ramesh, B.; Devarajulu, G. [Department of Physics, Sri Venkateswara University, Tirupati 517502 (India); Reddy, C. Madhukar [Department of Physics, AP Model School, Yerravaripalem 517194 (India); Linganna, K. [Department of Physics, Sri Venkateswara University, Tirupati 517502 (India); Reddy, G. Rajasekhar [Department of Instrumentation, Sri Venkateswara University, Tirupati 517502 (India); Raju, B. Deva Prasad, E-mail: drdevaprasadraju@gmail.com [Department of Physics, Sri Venkateswara University, Tirupati 517502 (India); Department of Future Studies, Sri Venkateswara University, Tirupati 517502 (India)

    2015-08-15

    A series of Er{sup 3+} ions doped tellurium calcium zinc niobium borate glasses were prepared by the melt quenching technique. The prepared samples were investigated by optical absorption and near infrared fluorescence spectroscopic studies. The obtained Judd–Ofelt intensity parameters Ω{sub λ} (λ=2, 4 and 6) were determined through experimental and calculated oscillator strengths obtained from absorption spectra and their results are studied and compared with reported literature. The stark-level energies of {sup 4}I{sub 13/2} excited and {sup 4}I{sub 15/2} ground states were evaluated by using both the absorption and emission measurements. The effect of Er{sup 3+} ion concentration on the emission intensity of {sup 4}I{sub 13/2}→{sup 4}I{sub 15/2} transition was discussed. Intense and broad 1.53 µm infrared fluorescence is observed at 980 nm diode laser excitation. Photoluminescence (PL) and its decay behavior studies were carried out for the transition {sup 4}I{sub 13/2}→{sup 4}I{sub 15/2} at 1.53 µm emission. The broad emission together with higher values of the bandwidth (81 nm), stimulated emission cross-section (32.25×10{sup −22} cm{sup 2}) and lifetime (530 µs for 1.0 mol% of Er{sup 3+}) of level {sup 4}I{sub 13/2} make these glasses attractive for broadband amplifiers. From the analysis of spectroscopic data, the present glass is a prospective photonic material for practical applications in the visible and NIR region. - Highlights: • In this study we prepared TCZNB glasses doped with Er{sup 3+} ions. • Glasses are characterized with absorption, emission and lifetime analysis. • Judd–Ofelt theory is used to calculate radiative properties. • TCZNB glasses could be used as NIR lasers.

  13. NIR fluorescence spectroscopic investigations of Er3+-ions doped borate based tellurium calcium zinc niobium oxide glasses

    International Nuclear Information System (INIS)

    A series of Er3+ ions doped tellurium calcium zinc niobium borate glasses were prepared by the melt quenching technique. The prepared samples were investigated by optical absorption and near infrared fluorescence spectroscopic studies. The obtained Judd–Ofelt intensity parameters Ωλ (λ=2, 4 and 6) were determined through experimental and calculated oscillator strengths obtained from absorption spectra and their results are studied and compared with reported literature. The stark-level energies of 4I13/2 excited and 4I15/2 ground states were evaluated by using both the absorption and emission measurements. The effect of Er3+ ion concentration on the emission intensity of 4I13/2→4I15/2 transition was discussed. Intense and broad 1.53 µm infrared fluorescence is observed at 980 nm diode laser excitation. Photoluminescence (PL) and its decay behavior studies were carried out for the transition 4I13/2→4I15/2 at 1.53 µm emission. The broad emission together with higher values of the bandwidth (81 nm), stimulated emission cross-section (32.25×10−22 cm2) and lifetime (530 µs for 1.0 mol% of Er3+) of level 4I13/2 make these glasses attractive for broadband amplifiers. From the analysis of spectroscopic data, the present glass is a prospective photonic material for practical applications in the visible and NIR region. - Highlights: • In this study we prepared TCZNB glasses doped with Er3+ ions. • Glasses are characterized with absorption, emission and lifetime analysis. • Judd–Ofelt theory is used to calculate radiative properties. • TCZNB glasses could be used as NIR lasers

  14. Eggshell powder, a comparable or better source of calcium than purified calcium carbonate: Piglet studies

    NARCIS (Netherlands)

    Schaafsma, A.; Beelen, G.M.

    1999-01-01

    Powdered chicken eggshells might be an interesting and widely available source of calcium. In two studies using piglets we determined the digestibility of calcium from different diets. The first study compared casein-based diets with CaCO3 (CasCC) or eggshell powder (CasES). The second study compare

  15. An Automated Parallel Image Registration Technique Based on the Correlation of Wavelet Features

    Science.gov (United States)

    LeMoigne, Jacqueline; Campbell, William J.; Cromp, Robert F.; Zukor, Dorothy (Technical Monitor)

    2001-01-01

    With the increasing importance of multiple platform/multiple remote sensing missions, fast and automatic integration of digital data from disparate sources has become critical to the success of these endeavors. Our work utilizes maxima of wavelet coefficients to form the basic features of a correlation-based automatic registration algorithm. Our wavelet-based registration algorithm is tested successfully with data from the National Oceanic and Atmospheric Administration (NOAA) Advanced Very High Resolution Radiometer (AVHRR) and the Landsat/Thematic Mapper(TM), which differ by translation and/or rotation. By the choice of high-frequency wavelet features, this method is similar to an edge-based correlation method, but by exploiting the multi-resolution nature of a wavelet decomposition, our method achieves higher computational speeds for comparable accuracies. This algorithm has been implemented on a Single Instruction Multiple Data (SIMD) massively parallel computer, the MasPar MP-2, as well as on the CrayT3D, the Cray T3E and a Beowulf cluster of Pentium workstations.

  16. A wavelet-based method to discriminate internal faults from inrush currents using correlation coefficient

    Energy Technology Data Exchange (ETDEWEB)

    Vahidi, B.; Ghaffarzadeh, N.; Hosseinian, S.H. [Dept. of Electrical Engineering, Amirkabir University of Technology, Tehran (Iran)

    2010-09-15

    In this paper a new method based on discrete wavelet transform and correlation coefficient is presented for digital differential protection. The algorithm includes offline and online operations. In offline operation, discrete wavelet transform is used to decompose typical three-phase differential currents for inrush current. Then an index is defined and computed. The index is based on the sum of the energy of detail coefficients at level 5 of three-phase differential currents at each half cycle. The online operation consists of capturing the three-phase differential currents using 10 kHz sampling rate, decomposing it by db1. Finally, the inrush current and internal fault is detected based on correlation coefficients of the computed index of pre-stored typical inrush current and a recorded indistinct signal. The effectiveness of the approach is tested using numerous inrush and internal fault currents. Simulations are used to confirm the aptness and the capability of the proposed method to discriminate inrush current from internal fault. (author)

  17. On the Entropy Based Associative Memory Model with Higher-Order Correlations

    Directory of Open Access Journals (Sweden)

    Masahiro Nakagawa

    2010-01-01

    Full Text Available In this paper, an entropy based associative memory model will be proposed and applied to memory retrievals with an orthogonal learning model so as to compare with the conventional model based on the quadratic Lyapunov functional to be minimized during the retrieval process. In the present approach, the updating dynamics will be constructed on the basis of the entropy minimization strategy which may be reduced asymptotically to the above-mentioned conventional dynamics as a special case ignoring the higher-order correlations. According to the introduction of the entropy functional, one may involve higer-order correlation effects between neurons in a self-contained manner without any heuristic coupling coefficients as in the conventional manner. In fact we shall show such higher order coupling tensors are to be uniquely determined in the framework of the entropy based approach. From numerical results, it will be found that the presently proposed novel approach realizes much larger memory capacity than that of the quadratic Lyapunov functional approach, e.g., associatron.

  18. The performance of 2D array detectors for light sheet based fluorescence correlation spectroscopy.

    Science.gov (United States)

    Singh, Anand Pratap; Krieger, Jan Wolfgang; Buchholz, Jan; Charbon, Edoardo; Langowski, Jörg; Wohland, Thorsten

    2013-04-01

    Single plane illumination microscopy based fluorescence correlation spectroscopy (SPIM-FCS) is a new method for imaging FCS in 3D samples, providing diffusion coefficients, transport, flow velocities and concentrations in an imaging mode. SPIM-FCS records correlation functions over a whole plane in a sample, which requires array detectors for recording the fluorescence signal. Several types of image sensors are suitable for FCS. They differ in properties such as effective area per pixel, quantum efficiency, noise level and read-out speed. Here we compare the performance of several low light array detectors based on three different technologies: (1) Single-photon avalanche diode (SPAD) arrays, (2) passive-pixel electron multiplying charge coupled device (EMCCD) and (3) active-pixel scientific-grade complementary metal oxide semiconductor cameras (sCMOS). We discuss the influence of the detector characteristics on the effective FCS observation volume, and demonstrate that light sheet based SPIM-FCS provides absolute diffusion coefficients. This is verified by parallel measurements with confocal FCS, single particle tracking (SPT), and the determination of concentration gradients in space and time. While EMCCD cameras have a temporal resolution in the millisecond range, sCMOS cameras and SPAD arrays can extend the time resolution of SPIM-FCS down to 10 μs or lower. PMID:23571955

  19. Bioactive glass incorporation in calcium phosphate cement-based injectable bone substitute for improved in vitro biocompatibility and in vivo bone regeneration.

    Science.gov (United States)

    Sadiasa, Alexander; Sarkar, Swapan Kumar; Franco, Rose Ann; Min, Young Ki; Lee, Byong Taek

    2014-01-01

    In this work, we fabricated injectable bone substitutes modified with the addition of bioactive glass powders synthesized via ultrasonic energy-assisted hydrothermal method to the calcium phosphate-based bone cement to improve its biocompatibility. The injectable bone substitutes was initially composed of a powder component (tetracalcium phosphate, dicalcium phosphate dihydrate and calcium sulfate dehydrate) and a liquid component (citric acid, chitosan and hydroxyl-propyl-methyl-cellulose) upon which various concentrations of bioactive glass were added: 0%, 10%, 20% and 30%. Setting time and compressive strength of the injectable bone substitutes were evaluated and observed to improve with the increase of bioactive glass content. Surface morphologies were observed via scanning electron microscope before and after submersion of the samples to simulated body fluid and increase in apatite formation was detected using x-ray diffraction machine. In vitro biocompatibility of the injectable bone substitutes was observed to improve with the addition of bioactive glass as the proliferation/adhesion behavior of cells on the material increased. Human gene markers were successfully expressed using real time-polymerase chain reaction and the samples were found to promote cell viability and be more biocompatible as the concentration of bioactive glass increases. In vivo biocompatibility of the samples containing 0% and 30% bioactive glass were evaluated using Micro-CT and histological staining after 3 months of implantation in male rabbits' femurs. No inflammatory reaction was observed and significant bone formation was promoted by the addition of bioactive glass to the injectable bone substitute system.

  20. Evaluation and comparison of the efficacy of low fluoridated and calcium phosphate-based dentifrice formulations when used with powered and manual toothbrush in children with autism

    Directory of Open Access Journals (Sweden)

    Prateek Awasthi

    2015-01-01

    Full Text Available Background: Autism is a neurobiological disorder characterized by impaired social interaction, communication difficulties, and lacking manual dexterity. These limitations make the oral hygiene maintenance very difficult. Aim: The aim of this present study is to evaluate and compare the efficacy of low fluoridated and calcium phosphate-based dentifrice formulations when used with powered and manual toothbrush in children with autism. Setting and Design: Sample comprised 22 children with autism who daily visited a day care and education center named ARUSHI - a center for children with special health care needs in Bhopal. Methods: Children were divided into two groups (Group A and B according to toothbrush used and further divided into subgroups (A1 and B1 [low fluoridated − Pediflor toothpaste] and A2 and B2 [calcium sucrose phosphate − Enafix toothpaste]. Oral hygiene instructions and brushing technique demonstration were given every day for a period of 1-month. Oral health status was evaluated before and after the study using simplified oral hygiene index (OHI-S and its Miglani's modification for primary dentition, plaque index (PI, gingival index (GI, and decayed, missing, and filled teeth (DMFT/deft index. The perception of parents regarding oral hygiene practices for their kids was also evaluated by an awareness and attitude questionnaire. Statistical Analysis: OHI-S, GI, PI, and DMFT/deft were statistically evaluated using Mann–Whitney U- test. Results and Conclusion: Mean value of OHI-S decreased significantly with powered toothbrush (0.035 [P < 0.05] in both groups. However, PI decreased significantly for Enafix when used with powered toothbrush (0.042 [P < 0.05]. Perception of parents was seen to improve significantly after 1-month study (0.000 [P < 0.05].

  1. Attempt of alpine glacier flow modeling based on correlation measurements of high resolution SAR images

    OpenAIRE

    Yan, Yajing; Ferro-Famil, Laurent; Gay, Michel; Fallourd, Renaud; Trouvé, Emmanuel; Vernier, Flavien

    2013-01-01

    International audience In this paper, an attempt of Alpine glacier flow modeling is performed based on a series of high resolution TerraSAR-X SAR images and a Digital Elevation Model. First, a glacier flow model is established according to the fluid mechanics theory in a simplified framework. Second, the displacement field over the glacier obtained from the sub-pixel image correlation of a series of TerraSAR-X SAR images is used to refine the model obtained previously. The comparison betwe...

  2. Harmonic detection an AC excited generation system based on in-phase correlation filtering

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The paper reports results of investigation on the harmonic detection technique of a complicated power supply system such as an AC excited generation system, which has a variable fundamental frequency and low order harmonics with rich sub-harmonics whose frequencies are lower than the fundamental one. The in-phase correlation filtering technique, based on the frequency shifting principle, is proposed in this paper. Theoretical analysis and experimental results validate the effectiveness of this technique for the harmonic detections of AC excited generation systems.

  3. Algorithm for Target Recognition Based on Interval-Valued Intuitionistic Fuzzy Sets with Grey Correlation

    Directory of Open Access Journals (Sweden)

    Xuan Huang

    2016-01-01

    Full Text Available In order to improve exact recognition ratios for aerial targets, this paper presents a novel algorithm for target recognition based on interval-valued intuitionistic fuzzy sets with grey correlation. Drawbacks of some previously proposed methods are analyzed, and then a novel algorithm is presented. Recognition matrix of an aerial target is established first. Every entry associated with the matrix is an interval-valued intuitionistic fuzzy number, which is composed of interval-valued membership and nonmembership, representing the relation of the target to one category in terms of one characteristic parameter. Then grey correlation theory is used to analyze the recognition matrix to obtain the grey correlation degree of this unknown target to every category. 200 sets of target recognition data are used to compare the proposed algorithm with traditional methods. Experimental results verify that the correct recognition ratio can be up to 99.5% that satisfies the expectations, which shows the proposed algorithm can solve the target recognition problems better. The proposed algorithm can be used to solve the uncertain inference problems, such as target recognition, threat assessment, and decision making.

  4. Socio-economic factors of bacillary dysentery based on spatial correlation analysis in Guangxi Province, China.

    Directory of Open Access Journals (Sweden)

    Chengjing Nie

    Full Text Available BACKGROUND: In the past decade, bacillary dysentery was still a big public health problem in China, especially in Guangxi Province, where thousands of severe diarrhea cases occur every year. METHODS: Reported bacillary dysentery cases in Guangxi Province were obtained from local Centers for Diseases Prevention and Control. The 14 socio-economic indexes were selected as potential explanatory variables for the study. The spatial correlation analysis was used to explore the associations between the selected factors and bacillary dysentery incidence at county level, which was based on the software of ArcGIS10.2 and GeoDA 0.9.5i. RESULTS: The proportion of primary industry, the proportion of younger than 5-year-old children in total population, the number of hospitals per thousand persons and the rates of bacillary dysentery incidence show statistically significant positive correlation. But the proportion of secondary industry, per capital GDP, per capital government revenue, rural population proportion, popularization rate of tap water in rural area, access rate to the sanitation toilets in rural, number of beds in hospitals per thousand persons, medical and technical personnel per thousand persons and the rate of bacillary dysentery incidence show statistically significant negative correlation. The socio-economic factors can be divided into four aspects, including economic development, health development, medical development and human own condition. The four aspects were not isolated from each other, but interacted with each other.

  5. Wavelet-based cross-correlation analysis of structure scaling in turbulent clouds

    CERN Document Server

    Arshakian, T G

    2015-01-01

    We propose a statistical tool to compare the scaling behaviour of turbulence in pairs of molecular cloud maps. Using artificial maps with well defined spatial properties, we calibrate the method and test its limitations to ultimately apply it to a set of observed maps. We develop the wavelet-based weighted cross-correlation (WWCC) method to study the relative contribution of structures of different sizes and their degree of correlation in two maps as a function of spatial scale, and the mutual displacement of structures in the molecular cloud maps. We test the WWCC for circular structures having a single prominent scale and fractal structures showing a self-similar behavior without prominent scales. Observational noise and a finite map size limit the scales where the cross-correlation coefficients and displacement vectors can be reliably measured. For fractal maps containing many structures on all scales, the limitation from the observational noise is negligible for signal-to-noise ratios >5. (abbrev). Applic...

  6. SPEECH ENHANCEMENT BASED ON DYNAMIC NOISE ESTIMATION WITHIN AUTO-CORRELATION DOMAIN

    Institute of Scientific and Technical Information of China (English)

    吴亚栋; 吴旭辉

    2002-01-01

    Most noise suppression algorithms of single channel use the mean of noisy segments to estimate the characteristics of noise spectrum, ignoring the estimation of noise in speech segments. Therefore, when the energy level of noise varies with the time, the performance of removing noise will be degraded. To solve this problem, a speech enhancement approach based on dynamic noise estimation within correlation domain was proposed. This method exploits the characteristics that noise energy mainly concentrates on 0 th-order correlation coefficients, signal is auto-correlated but signal and noise, noise and noise are uncorrelated, then estimates and decomposes the noise, thus helps to solve the above-mentioned problem. The results of recognition experiments on speech signals of 15 Chinese cities' names corrupted by noise of exhibition hall shows, this approach is better than SS (Spectral Subtraction) method, adapts better to the variances of energy levels of speech signal corrupted by noise, has some practicability to improve the robustness of recognition systems under noisy environment.

  7. Normal liver enzymes are correlated with severity of metabolic syndrome in a large population based cohort.

    Science.gov (United States)

    Kälsch, Julia; Bechmann, Lars P; Heider, Dominik; Best, Jan; Manka, Paul; Kälsch, Hagen; Sowa, Jan-Peter; Moebus, Susanne; Slomiany, Uta; Jöckel, Karl-Heinz; Erbel, Raimund; Gerken, Guido; Canbay, Ali

    2015-01-01

    Key features of the metabolic syndrome are insulin resistance and diabetes. The liver as central metabolic organ is not only affected by the metabolic syndrome as non-alcoholic fatty liver disease (NAFLD), but may contribute to insulin resistance and metabolic alterations. We aimed to identify potential associations between liver injury markers and diabetes in the population-based Heinz Nixdorf RECALL Study. Demographic and laboratory data were analyzed in participants (n = 4814, age 45 to 75 y). ALT and AST values were significantly higher in males than in females. Mean BMI was 27.9 kg/m(2) and type-2-diabetes (known and unkown) was present in 656 participants (13.7%). Adiponectin and vitamin D both correlated inversely with BMI. ALT, AST, and GGT correlated with BMI, CRP and HbA1c and inversely correlated with adiponectin levels. Logistic regression models using HbA1c and adiponectin or HbA1c and BMI were able to predict diabetes with high accuracy. Transaminase levels within normal ranges were closely associated with the BMI and diabetes risk. Transaminase levels and adiponectin were inversely associated. Re-assessment of current normal range limits should be considered, to provide a more exact indicator for chronic metabolic liver injury, in particular to reflect the situation in diabetic or obese individuals. PMID:26269425

  8. Feature-based alert correlation in security systems using self organizing maps

    Science.gov (United States)

    Kumar, Munesh; Siddique, Shoaib; Noor, Humera

    2009-04-01

    The security of the networks has been an important concern for any organization. This is especially important for the defense sector as to get unauthorized access to the sensitive information of an organization has been the prime desire for cyber criminals. Many network security techniques like Firewall, VPN Concentrator etc. are deployed at the perimeter of network to deal with attack(s) that occur(s) from exterior of network. But any vulnerability that causes to penetrate the network's perimeter of defense, can exploit the entire network. To deal with such vulnerabilities a system has been evolved with the purpose of generating an alert for any malicious activity triggered against the network and its resources, termed as Intrusion Detection System (IDS). The traditional IDS have still some deficiencies like generating large number of alerts, containing both true and false one etc. By automatically classifying (correlating) various alerts, the high-level analysis of the security status of network can be identified and the job of network security administrator becomes much easier. In this paper we propose to utilize Self Organizing Maps (SOM); an Artificial Neural Network for correlating large amount of logged intrusion alerts based on generic features such as Source/Destination IP Addresses, Port No, Signature ID etc. The different ways in which alerts can be correlated by Artificial Intelligence techniques are also discussed. . We've shown that the strategy described in the paper improves the efficiency of IDS by better correlating the alerts, leading to reduced false positives and increased competence of network administrator.

  9. Correlation Detection Based on the Reconstructed Excitation Signal of Electromagnetic Seismic Vibrator

    Science.gov (United States)

    Yang, Z.; Jiang, T.; Xu, X.; Jia, H.

    2014-12-01

    Correlation detection method is generally used to detect seismic data of electromagnetic seismic vibrator, which is widely applicated for shallow mineral prospecting. By analyzing field seismic data from electromagnetic and hydraulic seismic vibrators in mining area, we find when media underground is complex or the base-plate of vibrator is coupled poorly with ground, there is a 9.30 m positioning precision error and false multiple waves in the electromagnetic vibrator data reference to hydraulic vibrator data. The paper analyzes the theoretical reason of above problems by studying how the signal of electromagnetic vibrator is excited, then proposes a new method of correlation detection based on the reconstructed excitation signal (CDBRES). CDBRES includes following steps. First, it extracts the direct wave signal from seismometer near base-plate of electromagnetic vibrator. Next, it reconstructs the excitation signal according to the extracted direct wave. Then, it detects the seismic data using cross-correlation with the reconstructed excitation signal as a reference. Finally, it uses spectrum whitening to improve detection quality. We simulate with ray-tracing method, and simulation results show that the reconstructed excitation signal is extremely consistence with the ideal excitation signal, the correlation coefficient between them is up to 0.9869. And the signal of electromagnetic vibrator is detected correctly with CDBRES method. Then a field comparison experiment between hydraulic vibrator MiniVib T15000 and electromagnetic vibrator PHVS 500 was carried out near a copper and nickel deposit area. Their output force are 30000N and 300N, respectively. Though there is a great output force difference, the detection result of PHVS 500 using CDBRES method is still consistent with MiniVib T15000. Reference to the MiniVib T15000, the positioning error of PHVS 500 is only 0.93m in relatively stronger noise level. In addition, false multiple waves are invisible. In

  10. Analyses on schedule-cost coefficient correlation of spaceflight project based on historical statistics and its application

    Institute of Scientific and Technical Information of China (English)

    Liu Yanqiong; Chen Yingwu

    2006-01-01

    When analyze the uncertainty of the cost and the schedule of the spaceflight project, it is needed to know the value of the schedule-cost correlation coefficient. This paper deduces the schedule distribution, considering the effect of the cost, and proposes the estimation formula of the correlation coefficient between the ln(schedule) and the cost. On the basis of the fact and Taylor expansion, the relation expression between the schedule-cost correlation coefficient and the ln-schedule-cost correlation coefficient is put forward. By analyzing the value features of the estimation formula of the ln-schedule-cost correlation coefficient, the general rules are proposed to ascertain the value of the schedule-cost correlation coefficient. An example is given to demonstrate how to approximately amend the schedule-cost correlation coefficient based on the historical statistics, which reveals the traditional assigned value is inaccurate. The universality of this estimation method is analyzed.

  11. Mechanistic effects of IVIg in neuroinflammatory diseases: conclusions based on clinicopathologic correlations.

    Science.gov (United States)

    Dalakas, Marinos C

    2014-07-01

    The mechanisms of action of IVIg on immunoregulatory and neuroinflammatory network have been predominantly based on in vitro experiments and animal studies, rather than direct effects on human tissues. Based on clinicopathologic correlations and tissues obtained before and after IVIg therapy, the better documented and clinically-relevant in-vivo actions of IVIg include effects on: a) Antibodies. An extracted antigen-specific anti-immunoglobulin (idiotypic) fraction appears partially responsible for its effect in myasthenia gravis and GBS; b) Complement. Sera from Dermatomyositis (DM) patients responding to IVIg, inhibit complement consumption and intercept MAC formation leading to disappearance of MAC deposits in the repeated muscle biopsies and normalization of muscle tissue; c) Genes. In repeated muscle biopsies from DM patients who improved after IVIg, but not from Inclusion-Body-Myositis (IBM) who did not improve, there is a 2-fold alteration of 2206 tissue genes associated with inflammation, fibrosis, tissue remodeling and regeneration; and d) degenerative-proinflammatory molecules and β-amyloid, implicated in neurodegenerative CNS diseases and IBM. In repeated muscle biopsies of IBM patients who did not respond to IVIg, the mRNA or protein expression for chemokines, IFN-γ, TGF-ß, IL-10, Ubiquitin and aB-crystallin is reduced, but not for the key molecules ICOS, ICOSL, IL-6, IL1-β, perforin, APP, nitric oxide synthase and nitrotyrosine, in spite of good IVIg penetration in muscles. Collectively, the selective effectiveness of IVIg in human diseases seems to correlate in vivo with inhibition of causative inflammatory mediators. Study of accessible tissues before and after therapy and clinicopathologic correlations, may help explain the differential effect of IVIg in autoimmune or neuroinflammatory diseases.

  12. Study on an auto-correlation-function-based damage index: Sensitivity analysis and structural damage detection

    Science.gov (United States)

    Zhang, Muyu; Schmidt, Rüdiger

    2015-12-01

    The damage index based on the auto correlation function to detect the damage of the structure under white noise excitation is studied in detail in this paper. The maximum values of the auto correlation function of the vibration response signals (displacement, velocity and acceleration) from different measurement points of the structure are collected and formulated as a vector called Auto Correlation Function at Maximum Point Value Vector (AMV), which is expressed as a weighted combination of the Hadamard product of two mode shapes. AMV is normalized by its root mean square value so that the influence of the excitation can be eliminated. Sensitivity analysis for the different parts of the normalized AMV shows that the sensitivity of the normalized AMV to the local stiffness is dependent most on the sensitivity of the Hadamard product of the two lower order mode shapes to the local stiffness, which has a sudden change of the value around the local stiffness change position. The sensitivity of the normalized AMV has the similar shape and same trend that shows it is a very good damage indicator even for the very small damage. The relative change of the normalized AMV before and after damage occurs in the structure is adopted as the damage index to show the damage location. Several examples of the stiffness reduction detection of a 12-story shear frame structure are utilized to validate the results in sensitivity analysis, illustrate the effectiveness and anti-noise ability of the AMV-based damage detection method and compare the effect of the response type on the detectability of the normalized AMV.

  13. Correlations Based on CFD and Their Applications in Optimization for Staggered and Parallel Plate Fin Heatsinks

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Both parallel and staggered plate fin arrays have shown promise for use in high performance heatsinks regard of its individual manufacturing costs. The geometrical and operational parameters are very important to their cooling performance as heatsinks in practical applications. Fluent 5.0 commercial CFD (computational fluid dynamic) code is used to simulate the flow and heat transfer of those heatsinks of different realistic parameters. Based on those simulations, two correlations, concerning Nusselt number and friction factor as the functions of geometrical and operational parameters, FB (fin-base area ratio), PR (ratio of spanwise pitch to lengthwise pitch) and Re, were developed. From the both, the performance comparisons for optimizing geometrical and operational parameters of a fixed dimension heatsink are shown at constant pumping power and constant thermal resistance. Several optimized parameters were obtained with the discussion to various goals in real application. It demonstrates that in some particular situations, the parallel plate fin heatsinks can out perform the staggered ones.

  14. Correlation Between Superheated Liquid Fragility And Onset Temperature Of Crystallization For Al-Based Amorphous Alloys

    Directory of Open Access Journals (Sweden)

    Guo J.

    2015-06-01

    Full Text Available Amorphous alloys or metallic glasses have attracted significant interest in the materials science and engineering communities due to their unique physical, mechanical, and chemical properties. The viscous flow of amorphous alloys exhibiting high strain rate sensitivity and homogeneous deformation is considered to be an important characteristic in thermoplastic forming processes performed within the supercooled liquid region because it allows superplastic-like deformation behavior. Here, the correlation between the superheated liquid fragility, and the onset temperature of crystallization for Al-based alloys, is investigated. The activation energy for viscous flow of the liquid is also investigated. There is a negative correlation between the parameter of superheated liquid fragility and the onset temperature of crystallization in the same Al-based alloy system. The activation energy decreases as the onset temperature of crystallization increases. This indicates that the stability of a superheated liquid can affect the thermal stability of the amorphous alloy. It also means that a liquid with a large superheated liquid fragility, when rapidly solidified, forms an amorphous alloy with a low thermal stability.

  15. Fully phase color image encryption based on joint fractional Fourier transform correlator and phase retrieval algorithm

    Institute of Scientific and Technical Information of China (English)

    Ding Lu; Weimin Jin

    2011-01-01

    A novel fully phase color image encryption/decryption scheme based on joint fractional Fourier transform correlator (JFRTC) and phase retrieval algorithm (PRA) is proposed. The security of the system is enhanced by the fractional order as a new added key. This method takes full advantage of the parallel processing features of the optical system and could optically realize single-channel color image encryption.The system and operation procedures are simplified. The simulation results of a color image indicate that the new method provides efficient solutions with a strong sense of security.%@@ A novel fully phase color image encryption/decryption scheme based on joint fractional Fourier transform correlator (JFRTC) and phase retrieval algorithm (PRA) is proposed. The security of the system is enhanced by the fractional order as a new added key. This method takes full advantage of the parallel processing features of the optical system and could optically realize single-channel color image encryption. The system and operation procedures are simplified. The simulation results of a color image indicate that the new method provides efficient solutions with a strong sense of security.

  16. Calcium in plant cells

    Directory of Open Access Journals (Sweden)

    V. V. Schwartau

    2014-04-01

    Full Text Available The paper gives the review on the role of calcium in many physiological processes of plant organisms, including growth and development, protection from pathogenic influences, response to changing environmental factors, and many other aspects of plant physiology. Initial intake of calcium ions is carried out by Ca2+-channels of plasma membrane and they are further transported by the xylem owing to auxins’ attractive ability. The level of intake and selectivity of calcium transport to ove-ground parts of the plant is controlled by a symplast. Ca2+enters to the cytoplasm of endoderm cells through calcium channels on the cortical side of Kaspary bands, and is redistributed inside the stele by the symplast, with the use of Ca2+-АТPases and Ca2+/Н+-antiports. Owing to regulated expression and activity of these calcium transporters, calclum can be selectively delivered to the xylem. Important role in supporting calcium homeostasis is given to the vacuole which is the largest depo of calcium. Regulated quantity of calcium movement through the tonoplast is provided by a number of potential-, ligand-gated active transporters and channels, like Ca2+-ATPase and Ca2+/H+ exchanger. They are actively involved in the inactivation of the calcium signal by pumping Ca2+ to the depo of cells. Calcium ATPases are high affinity pumps that efficiently transfer calcium ions against the concentration gradient in their presence in the solution in nanomolar concentrations. Calcium exchangers are low affinity, high capacity Ca2+ transporters that are effectively transporting calcium after raising its concentration in the cell cytosol through the use of protons gradients. Maintaining constant concentration and participation in the response to stimuli of different types also involves EPR, plastids, mitochondria, and cell wall. Calcium binding proteins contain several conserved sequences that provide sensitivity to changes in the concentration of Ca2+ and when you

  17. NEW TRACK-TO-TRACK CORRELATION ALGORITHMS BASED ON BITHRESHOLD IN A DISTRIBUTED MULTISENSOR INFORMATION FUSION SYSTEM

    OpenAIRE

    Liu Yu; Wang Haipeng; He You; Dong Kai; Xiao Chuwan

    2013-01-01

    Track-to-Track correlation (or association) is an ongoing area of interest in the field of distributed multisensory information fusion. In order to perform accurately identifying tracks with common origin and get fast convergence, this study presents independent and dependent Bi-threshold Track Correlation Algorithms (called BTCAs), which are described in detail and the track correlation mass and multivalency processing methods are discussed as well. Then, Based on BTCAs, two modified Bi-thre...

  18. Comparison of subset-based local and FE-based global digital image correlation: Theoretical error analysis and validation

    KAUST Repository

    Pan, B.

    2016-03-22

    Subset-based local and finite-element-based (FE-based) global digital image correlation (DIC) approaches are the two primary image matching algorithms widely used for full-field displacement mapping. Very recently, the performances of these different DIC approaches have been experimentally investigated using numerical and real-world experimental tests. The results have shown that in typical cases, where the subset (element) size is no less than a few pixels and the local deformation within a subset (element) can be well approximated by the adopted shape functions, the subset-based local DIC outperforms FE-based global DIC approaches because the former provides slightly smaller root-mean-square errors and offers much higher computation efficiency. Here we investigate the theoretical origin and lay a solid theoretical basis for the previous comparison. We assume that systematic errors due to imperfect intensity interpolation and undermatched shape functions are negligibly small, and perform a theoretical analysis of the random errors or standard deviation (SD) errors in the displacements measured by two local DIC approaches (i.e., a subset-based local DIC and an element-based local DIC) and two FE-based global DIC approaches (i.e., Q4-DIC and Q8-DIC). The equations that govern the random errors in the displacements measured by these local and global DIC approaches are theoretically derived. The correctness of the theoretically predicted SD errors is validated through numerical translation tests under various noise levels. We demonstrate that the SD errors induced by the Q4-element-based local DIC, the global Q4-DIC and the global Q8-DIC are 4, 1.8-2.2 and 1.2-1.6 times greater, respectively, than that associated with the subset-based local DIC, which is consistent with our conclusions from previous work. © 2016 Elsevier Ltd. All rights reserved.

  19. Comparison of subset-based local and FE-based global digital image correlation: Theoretical error analysis and validation

    Science.gov (United States)

    Pan, B.; Wang, B.; Lubineau, G.

    2016-07-01

    Subset-based local and finite-element-based (FE-based) global digital image correlation (DIC) approaches are the two primary image matching algorithms widely used for full-field displacement mapping. Very recently, the performances of these different DIC approaches have been experimentally investigated using numerical and real-world experimental tests. The results have shown that in typical cases, where the subset (element) size is no less than a few pixels and the local deformation within a subset (element) can be well approximated by the adopted shape functions, the subset-based local DIC outperforms FE-based global DIC approaches because the former provides slightly smaller root-mean-square errors and offers much higher computation efficiency. Here we investigate the theoretical origin and lay a solid theoretical basis for the previous comparison. We assume that systematic errors due to imperfect intensity interpolation and undermatched shape functions are negligibly small, and perform a theoretical analysis of the random errors or standard deviation (SD) errors in the displacements measured by two local DIC approaches (i.e., a subset-based local DIC and an element-based local DIC) and two FE-based global DIC approaches (i.e., Q4-DIC and Q8-DIC). The equations that govern the random errors in the displacements measured by these local and global DIC approaches are theoretically derived. The correctness of the theoretically predicted SD errors is validated through numerical translation tests under various noise levels. We demonstrate that the SD errors induced by the Q4-element-based local DIC, the global Q4-DIC and the global Q8-DIC are 4, 1.8-2.2 and 1.2-1.6 times greater, respectively, than that associated with the subset-based local DIC, which is consistent with our conclusions from previous work.

  20. Calcium D-saccharate

    DEFF Research Database (Denmark)

    Garcia, André Castilho; Hedegaard, Martina Vavrusova; Skibsted, Leif Horsfelt

    2016-01-01

    Molar conductivity of saturated aqueous solutions of calcium d-saccharate, used as a stabilizer of beverages fortified with calcium d-gluconate, increases strongly upon dilution, indicating complex formation between calcium and d-saccharate ions, for which, at 25 °C, Kassoc = 1032 ± 80, ΔHassoc......° = -34 ± 6 kJ mol-1, and ΔSassoc° = -55 ± 9 J mol-1 K-1, were determined electrochemically. Calcium d-saccharate is sparingly soluble, with a solubility product, Ksp, of (6.17 ± 0.32) × 10-7 at 25 °C, only moderately increasing with the temperature: ΔHsol° = 48 ± 2 kJ mol-1, and ΔSassoc° = 42 ± 7 J mol-1...... K-1. Equilibria in supersaturated solutions of calcium d-saccharate seem only to adjust slowly, as seen from calcium activity measurements in calcium d-saccharate solutions made supersaturated by cooling. Solutions formed by isothermal dissolution of calcium d-gluconate in aqueous potassium d...

  1. Empirical source strength correlations for rans-based acoustic analogy methods

    Science.gov (United States)

    Kube-McDowell, Matthew Tyndall

    JeNo is a jet noise prediction code based on an acoustic analogy method developed by Mani, Gliebe, Balsa, and Khavaran. Using the flow predictions from a standard Reynolds-averaged Navier-Stokes computational fluid dynamics solver, JeNo predicts the overall sound pressure level and angular spectra for high-speed hot jets over a range of observer angles, with a processing time suitable for rapid design purposes. JeNo models the noise from hot jets as a combination of two types of noise sources; quadrupole sources dependent on velocity fluctuations, which represent the major noise of turbulent mixing, and dipole sources dependent on enthalpy fluctuations, which represent the effects of thermal variation. These two sources are modeled by JeNo as propagating independently into the far-field, with no cross-correlation at the observer location. However, high-fidelity computational fluid dynamics solutions demonstrate that this assumption is false. In this thesis, the theory, assumptions, and limitations of the JeNo code are briefly discussed, and a modification to the acoustic analogy method is proposed in which the cross-correlation of the two primary noise sources is allowed to vary with the speed of the jet and the observer location. As a proof-of-concept implementation, an empirical correlation correction function is derived from comparisons between JeNo's noise predictions and a set of experimental measurements taken for the Air Force Aero-Propulsion Laboratory. The empirical correlation correction is then applied to JeNo's predictions of a separate data set of hot jets tested at NASA's Glenn Research Center. Metrics are derived to measure the qualitative and quantitative performance of JeNo's acoustic predictions, and the empirical correction is shown to provide a quantitative improvement in the noise prediction at low observer angles with no freestream flow, and a qualitative improvement in the presence of freestream flow. However, the results also demonstrate

  2. Serum calcium levels are not associated with coronary heart disease

    Directory of Open Access Journals (Sweden)

    Jin Y

    2013-09-01

    Full Text Available Yuelong Jin,* Lianping He,* Quanhai Wang, Yan Chen, Xiaohua Ren, Hui Tang, Xiuli Song, Lingling Ding, Qin Qi, Zhiwei Huang, Jiegen Yu, Yingshui Yao Department of Preventive Medicine, Wannan Medical College, Wuhu, People's Republic of China *These authors contributed equally to this work Background: Numerous studies have reported that low calcium intake is related to a higher prevalence of cardiovascular disease. However, the relationship between serum calcium and coronary heart disease is unclear. The purpose of this study was to compare serum calcium levels in patients with coronary heart disease and those in healthy individuals. Methods: This retrospective, case-control study conducted in the People's Republic of China comprised 380 cases and 379 controls. Serum calcium levels, blood lipids, and anthropometric measurements were measured in both groups. The Student's unpaired t-test or Chi-square test was used to compare differences between cases and controls. Pearson's partial correlation coefficient was used to determine the association between serum calcium, blood lipids, and blood pressure in both groups. Results: Our results indicate that the average level of serum calcium in cases was higher than in controls. Serum calcium levels showed no correlation with any parameter except for triglycerides in either group. Conclusion: Overall, these data suggest that serum calcium has no influence on coronary heart disease or triglyceride levels in the general population. Keywords: serum calcium, hypertension, blood lipids

  3. Correlation of centroid-based breast size, surface-based breast volume, and asymmetry-score-based breast symmetry in three-dimensional breast shape analysis

    Directory of Open Access Journals (Sweden)

    Henseler, Helga

    2016-06-01

    Full Text Available Objective: The aim of this study was to investigate correlations among the size, volume, and symmetry of the female breast after reconstruction based on previously published data. Methods: The centroid, namely the geometric center of a three-dimensional (3D breast-landmark-based configuration, was used to calculate the size of the breast. The surface data of the 3D breast images were used to measure the volume. Breast symmetry was assessed by the Procrustes analysis method, which is based on the 3D coordinates of the breast landmarks to produce an asymmetry score. The relationship among the three measurements was investigated. For this purpose, the data of 44 patients who underwent unilateral breast reconstruction with an extended latissimus dorsi flap were analyzed. The breast was captured by a validated 3D imaging system using multiple cameras. Four landmarks on each breast and two landmarks marking the midline were used.Results: There was a significant positive correlation between the centroid-based breast size of the unreconstructed breast and the measured asymmetry (p=0.024; correlation coefficient, 0.34. There was also a significant relationship between the surface-based breast volume of the unaffected side and the overall asymmetry score (p<0.001; correlation coefficient, 0.556. An increase in size and especially in volume of the unreconstructed breast correlated positively with an increase in breast asymmetry in a linear relationship.Conclusions: In breast shape analysis, the use of more detailed surface-based data should be preferred to centroid-based size data. As the breast size increases, the latissimus dorsi flap for unilateral breast reconstruction increasingly falls short in terms of matching the healthy breast in a linear relationship. Other reconstructive options should be considered for larger breasts. Generally plastic surgeons should view the two breasts as a single unit when assessing breast aesthetics and not view each

  4. Calcium And Zinc Deficiency In Preeclamptic Women

    Directory of Open Access Journals (Sweden)

    Sultana Ferdousi

    2011-12-01

    Full Text Available Background: Pre-eclampsia is the most common medical complication of pregnancy associated withincreased maternal and infant mortality and morbidity. Reduced serum calcium and zinc levels arefound associated with elevated blood pressure in preeclampsia. Objective: To observe serum calciumand zinc levels in preeclamptic women. Methods: This cross sectional study was carried out in theDepartment of Physiology, Bangabandhu Sheikh Mujib Medical University, Shahbag, Dhaka betweenJuly 2009 to June 2010. In this study, 60 pregnant women of preeclampsia, aged 18-39 years withgestational period more than 20th weeks were included as the study (group B. For comparison ageand gestational period matched 30 normotensive pregnant women control (group A were also studied.All the subjects were selected from Obstetric and Gynae In and Out patient Department of BSMMUand Dhaka Medical College Hospital. Serum calcium was measured by Colorimetric method and serumzinc was measured by Spectrophotometric method. Data were analysed by independent sample t testand Pearson’s correlation coefficient test. Results: Mean serum calcium and zinc levels weresignificantly (p<0.001 lower in study group than those of control group. Again, serum calcium andzinc showed significant negative correlation with SBP and DBP in preeclamptic women. Conclusion:This study concludes that serum calcium and zinc deficiency may be one of the risk factor ofpreeclampsia. Therefore, early detection and supplementation to treat this deficiency may reduce theincidence of preeclampsia.

  5. CORRELATIONS BETWEEN HOT CALCIUM CHLORIDE-EXTRACTED BORON AND CHEMICAL AND PHYSICAL ATTRIBUTES OF SOME BRAZILIAN SOILS CORRELAÇÕES ENTRE BORO SOLÚVEL EM CLORETO DE CÁLCIO 0,01 mol L-1 A QUENTE E ATRIBUTOS QUÍMICOS E FÍSICOS DE ALGUNS SOLOS BRASILEIROS

    Directory of Open Access Journals (Sweden)

    Luís Reynaldo Ferracciú Alleoni

    1999-01-01

    Full Text Available Relationship between soluble boron extracted with a hot CaCl2 0.01 mol L-1 solution and pH; organic carbon; exchangeable cations; cation exchange capacity (CEC; base saturation; total, free and amorphous iron and aluminum oxide contents; clay content; and specific surface area were performed for surface and subsurface samples of five soils. The soils were a Rhodic Hapludox, an Arenic Paleudalf and three Typic Hapludox, all representative soils of the State of São Paulo, Brazil. To quantify the relations between soluble boron and the different soil characteristics, simple linear correlations and multiple regressions, using a stepwise regression program, were performed. Hot-CaCl2 extractable boron (HCB was significantly correlated with clay content (r = 0.69*, specific surface area (r = 0.68*, CEC (r = 0.63* and total aluminum oxides (r = 0.70* in all five soils. In addition, there was a correlation between HCB and organic carbon (r = 0.75* in the four Oxisols. The correlation coefficient between the product (carbon x clay and soluble boron contents was also highly significant (r = 0.78**. Multiple regression analysis showed that total aluminum oxide, as well as exchangeable calcium and aluminum, were correlated with HCB, explaining 85% of the variation. The product (carbon x clay took into account the effect of textural gradient and showed high positive correlation with hot-CaCl2 0.01 mol L-1extractable boron.Teores de boro solúveis em CaCl2 0,01 mol L-1 a quente, de amostras superficiais e subsuperficiais de dois Latossolos argilosos, dois Latossolos de textura média e um Podzólico Vermelho-Amarelo do Estado de São Paulo, Brasil, foram correlacionados com alguns de seus atributos químicos e físicos. As correlações entre boro solúvel e superfície específica (r = 0,68*, argila (r = 0,69*, CTC (r = 0,63* e alumínio total (r = 0,70* dos cinco solos e com o teor de carbono orgânico dos quatro Latossolos (r = 0,75* foram estatisticamente

  6. Biclustering of Gene Expression Data by Correlation-Based Scatter Search

    Directory of Open Access Journals (Sweden)

    Nepomuceno Juan A

    2011-01-01

    Full Text Available Abstract Background The analysis of data generated by microarray technology is very useful to understand how the genetic information becomes functional gene products. Biclustering algorithms can determine a group of genes which are co-expressed under a set of experimental conditions. Recently, new biclustering methods based on metaheuristics have been proposed. Most of them use the Mean Squared Residue as merit function but interesting and relevant patterns from a biological point of view such as shifting and scaling patterns may not be detected using this measure. However, it is important to discover this type of patterns since commonly the genes can present a similar behavior although their expression levels vary in different ranges or magnitudes. Methods Scatter Search is an evolutionary technique that is based on the evolution of a small set of solutions which are chosen according to quality and diversity criteria. This paper presents a Scatter Search with the aim of finding biclusters from gene expression data. In this algorithm the proposed fitness function is based on the linear correlation among genes to detect shifting and scaling patterns from genes and an improvement method is included in order to select just positively correlated genes. Results The proposed algorithm has been tested with three real data sets such as Yeast Cell Cycle dataset, human B-cells lymphoma dataset and Yeast Stress dataset, finding a remarkable number of biclusters with shifting and scaling patterns. In addition, the performance of the proposed method and fitness function are compared to that of CC, OPSM, ISA, BiMax, xMotifs and Samba using Gene the Ontology Database.

  7. Improvement of the healing of a rat tibia defect by means of a Calcium Carbonate based biopolymer mixed with Epidermal Growth Factor and Ascorbic Acid

    Science.gov (United States)

    Mendoza-Barrera, C.; Meléndez-Lira, M.; Hernández-Flores, C.; Lecona-Butrón, H.; García-López, E. S.

    2000-10-01

    At the present bone reparation is commonly solved by means of different graft types. Biomaterials such as hidroxyapatite, coraline, octacalcium phosphate and tricalcium phosphate are used. By other side there are factors like Epidermal Growth Factor (EGF), Fibroblast Growth Factor (TGF), Laminine, Ascorbic Acid (AA), etc. that stimulate the osteogenesis in fracture or bony defect. The goal of this work is to evaluate the effect of the addition of EGF and ascorbic acid to a Ca2CO3 based biopolymer in the healing of a rat tibia model to improve the consolidation with adequate bony quality. No implant rejection or inflammatory reaction was observed during a 5 weeks period in our in vivo studies. The evolution of the osteointegration has been followed employing scanning electronic microscopy (SEM), energy dispersive x-ray analysis (EDX), and biochemistry activity for calcium, phosphor and alkaline phosphatase. We conclude that the combined use of the based Ca2CO3 biopolymer with Ascorbic Acid and Epidermal Growth Factor (group B&AA&EGF) in vivo accelerates the process of bony repair, as compared with the other groups. The mixture B&AA&EGF provide a bridge in the lesion, helping in the cellular migration and increasing the collagen synthesis.

  8. Nano-scale spatial assessment of calcium distribution in coccolithophores using synchrotron-based nano-CT and STXM-NEXAFS.

    Science.gov (United States)

    Sun, Shiyong; Yao, Yanchen; Zou, Xiang; Fan, Shenglan; Zhou, Qing; Dai, Qunwei; Dong, Faqin; Liu, Mingxue; Nie, Xiaoqin; Tan, Daoyong; Li, Shuai

    2014-01-01

    Calcified coccolithophores generate calcium carbonate scales around their cell surface. In light of predicted climate change and the global carbon cycle, the biomineralization ability of coccoliths has received growing interest. However, the underlying biomineralization mechanism is not yet well understood; the lack of non-invasive characterizing tools to obtain molecular level information involving biogenic processes and biomineral components remain significant challenges. In the present study, synchrotron-based Nano-computed Tomography (Nano-CT) and Scanning Transmission X-ray Microscopy-Near-edge X-ray Absorption Fine Structure Spectromicroscopy (STXM-NEXAFS) techniques were employed to identify Ca spatial distribution and investigate the compositional chemistry and distinctive features of the association between biomacromolecules and mineral components of calcite present in coccoliths. The Nano-CT results show that the coccolith scale vesicle is similar as a continuous single channel. The mature coccoliths were intracellularly distributed and immediately ejected and located at the exterior surface to form a coccoshpere. The NEXAFS spectromicroscopy results of the Ca L edge clearly demonstrate the existence of two levels of gradients spatially, indicating two distinctive forms of Ca in coccoliths: a crystalline-poor layer surrounded by a relatively crystalline-rich layer. The results show that Sr is absorbed by the coccoliths and that Sr/Ca substitution is rather homogeneous within the coccoliths. Our findings indicate that synchrotron-based STXM-NEXAFS and Nano-CT are excellent tools for the study of biominerals and provide information to clarify biomineralization mechanism.

  9. Nano-Scale Spatial Assessment of Calcium Distribution in Coccolithophores Using Synchrotron-Based Nano-CT and STXM-NEXAFS

    Directory of Open Access Journals (Sweden)

    Shiyong Sun

    2014-12-01

    Full Text Available Calcified coccolithophores generate calcium carbonate scales around their cell surface. In light of predicted climate change and the global carbon cycle, the biomineralization ability of coccoliths has received growing interest. However, the underlying biomineralization mechanism is not yet well understood; the lack of non-invasive characterizing tools to obtain molecular level information involving biogenic processes and biomineral components remain significant challenges. In the present study, synchrotron-based Nano-computed Tomography (Nano-CT and Scanning Transmission X-ray Microscopy-Near-edge X-ray Absorption Fine Structure Spectromicroscopy (STXM-NEXAFS techniques were employed to identify Ca spatial distribution and investigate the compositional chemistry and distinctive features of the association between biomacromolecules and mineral components of calcite present in coccoliths. The Nano-CT results show that the coccolith scale vesicle is similar as a continuous single channel. The mature coccoliths were intracellularly distributed and immediately ejected and located at the exterior surface to form a coccoshpere. The NEXAFS spectromicroscopy results of the Ca L edge clearly demonstrate the existence of two levels of gradients spatially, indicating two distinctive forms of Ca in coccoliths: a crystalline-poor layer surrounded by a relatively crystalline-rich layer. The results show that Sr is absorbed by the coccoliths and that Sr/Ca substitution is rather homogeneous within the coccoliths. Our findings indicate that synchrotron-based STXM-NEXAFS and Nano-CT are excellent tools for the study of biominerals and provide information to clarify biomineralization mechanism.

  10. Astronomical calibration and global correlation of the Santonian (Cretaceous) based on the marine carbon isotope record

    Science.gov (United States)

    Thibault, N.; Jarvis, I.; Voigt, S.; Gale, A. S.; Attree, K.; Jenkyns, H. C.

    2016-06-01

    High-resolution records of bulk carbonate carbon isotopes have been generated for the Upper Coniacian to Lower Campanian interval of the sections at Seaford Head (southern England) and Bottaccione (central Italy). An unambiguous stratigraphic correlation is presented for the base and top of the Santonian between the Boreal and Tethyan realms. Orbital forcing of carbon and oxygen isotopes at Seaford Head points to the Boreal Santonian spanning five 405 kyr cycles (Sa1 to Sa5). Correlation of the Seaford Head time scale to that of the Niobrara Formation (Western Interior Basin) permits anchoring these records to the La2011 astronomical solution at the Santonian-Campanian (Sa/Ca) boundary, which has been recently dated to 84.19 ± 0.38 Ma. Among the five tuning options examined, option 2 places the Sa/Ca at the 84.2 Ma 405 kyr insolation minimum and appears as the most likely. This solution indicates that minima of the 405 kyr filtered output of the resistivity in the Niobrara Formation correlate to 405 kyr insolation minima in the astronomical solution and to maxima in the filtered δ13C of Seaford Head. We suggest that variance in δ13C is driven by climate forcing of the proportions of CaCO3 versus organic carbon burial on land and in oceanic basins. The astronomical calibration generates a 200 kyr mismatch of the Coniacian-Santonian boundary age between the Boreal Realm in Europe and the Western Interior, due either to diachronism of the lowest occurrence of the inoceramid Cladoceramus undulatoplicatus between the two regions or to remaining uncertainties of radiometric dating and cyclostratigraphic records.

  11. CT abnormality in multiple sclerosis analysis based on 28 probable cases and correlation with clinical manifestations

    International Nuclear Information System (INIS)

    In order to investigate the occurrence and nature of CT abnormality and its correlation with clinical manifestations in multiple sclerosis, 34 CT records obtained from 28 consecutive patients with probable multiple sclerosis were reviewed. Forty-six percent of all cases showed abnormal CT. Dilatation of cortical sulci was found in 39%; dilatation of the lateral ventricle in 36%; dilatation of prepontine or cerebello-pontine cistern and the fourth ventricle, suggesting brainstem atrophy, in 18%; dilatation of cerebellar sulci, superior cerebellar cistern and cisterna magna, suggesting cerebellar atrophy, in 11%. Low density area was found in the cerebral hemisphere in 11% of cases. Contrast enhancement, performed on 25 CT records, did not show any change. There was no correlation between CT abnormality and duration of the illness. Although abnormal CT tended to occur more frequently during exacerbations and chronic stable state than during remissions, the difference was not statistically significant. CT abnormalities suggesting brainstem atrophy, cerebellar atrophy or plaques were found exclusively during exacerbations and chronic stable state. The occurrence of CT abnormalities was not significantly different among various clinical forms which were classified based on clinically estimated sites of lesion, except that abnormal CT tended to occur less frequently in cases classified as the optic-spinal form. It is noteworthy that cerebral cortical atrophy and/or dilatation of the lateral ventricle were found in 31% of cases who did not show any clinical sign of cerebral involvement. There was a statistically significant correlation between CT abnormalities and levels of clinical disability. Eighty percent of the bedridden or severely disabled patients showed abnormal CT, in contrast with only 29% of those with moderate, slight or no disability. (author)

  12. Gel time of calcium acrylate grouting material.

    Science.gov (United States)

    Han, Tong-Chun

    2004-08-01

    Calcium acrylate is a polymerized grout, and can polymerize in an aqueous solution. The polymerization reaction utilizes ammonium persulfate as a catalyst and sodium thiosulfate as the activator. Based on the theory of reaction kinetics, this study on the relation between gel time and concentration of activator and catalyst showed that gel time of calcium acrylate is inversely proportional to activator and catalyst concentration. A formula of gel time is proposed, and an example is provided to verify the proposed formula. PMID:15236477

  13. Gel time of calcium acrylate grouting material

    Institute of Scientific and Technical Information of China (English)

    韩同春

    2004-01-01

    Calcium acrylate is a polymerized grout, and can polymerize in an aqueous solution. The polymerization reaction utilizes ammonium persulfate as a catalyst and sodium thiosulfate as the activator. Based on the theory of reaction kinetics, this study on the relation between gel time and concentration of activator and catalyst showed that gel time of calcium acrylate is inversely proportional to activator and catalyst concentration. A formula of gel time is proposed, and an example is provided to verify the proposed formula.

  14. Online Epileptic Seizure Prediction Using Wavelet-Based Bi-Phase Correlation of Electrical Signals Tomography.

    Science.gov (United States)

    Vahabi, Zahra; Amirfattahi, Rasoul; Shayegh, Farzaneh; Ghassemi, Fahimeh

    2015-09-01

    Considerable efforts have been made in order to predict seizures. Among these methods, the ones that quantify synchronization between brain areas, are the most important methods. However, to date, a practically acceptable result has not been reported. In this paper, we use a synchronization measurement method that is derived according to the ability of bi-spectrum in determining the nonlinear properties of a system. In this method, first, temporal variation of the bi-spectrum of different channels of electro cardiography (ECoG) signals are obtained via an extended wavelet-based time-frequency analysis method; then, to compare different channels, the bi-phase correlation measure is introduced. Since, in this way, the temporal variation of the amount of nonlinear coupling between brain regions, which have not been considered yet, are taken into account, results are more reliable than the conventional phase-synchronization measures. It is shown that, for 21 patients of FSPEEG database, bi-phase correlation can discriminate the pre-ictal and ictal states, with very low false positive rates (FPRs) (average: 0.078/h) and high sensitivity (100%). However, the proposed seizure predictor still cannot significantly overcome the random predictor for all patients. PMID:26126613

  15. Extracting flat-field images from scene-based image sequences using phase correlation

    Science.gov (United States)

    Caron, James N.; Montes, Marcos J.; Obermark, Jerome L.

    2016-06-01

    Flat-field image processing is an essential step in producing high-quality and radiometrically calibrated images. Flat-fielding corrects for variations in the gain of focal plane array electronics and unequal illumination from the system optics. Typically, a flat-field image is captured by imaging a radiometrically uniform surface. The flat-field image is normalized and removed from the images. There are circumstances, such as with remote sensing, where a flat-field image cannot be acquired in this manner. For these cases, we developed a phase-correlation method that allows the extraction of an effective flat-field image from a sequence of scene-based displaced images. The method uses sub-pixel phase correlation image registration to align the sequence to estimate the static scene. The scene is removed from sequence producing a sequence of misaligned flat-field images. An average flat-field image is derived from the realigned flat-field sequence.

  16. Analysis of Input and Output of China’s Agriculture Based on Canonical Correlation

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    I select effective irrigated area, consumption of agricultural chemical fertilizer, electricity consumed in rural areas, and total power of agricultural machinery as input variables of China’s agriculture; I select grain, bean, tobacco, oil-bearing crop and fruit as output variables of China’s agriculture. By using the data of China Statistical Yearbook in 2010, based on the analysis method of canonical correlation, I conduct research on the input and output of China’s agriculture. The results show that consumption of chemical fertilizer has the biggest impact on the agricultural output of China, followed by the input of total power of agricultural machinery; the canonical variable of agricultural output of China is mainly impacted by grain, oil-bearing crop and fruit; in terms of the selected variables, the output increase of grain, oil-bearing crop and fruit in China arises from the input increase of agricultural chemical fertilizer and machinery, and there is high-degree correlation between the two. According to the conclusions, the policy suggestions are put forward as follows: gradually decrease consumption of chemical fertilizer; increase the use of modern agricultural machinery; increase agricultural irrigation input.

  17. A LFP-tree based method for association rules mining in telecommunication alarm correlation analysis

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The mining of association rules is one of the primary methods used in telecommunication alarm correlation analysis,of which the alarm databases are very large.The efficiency of the algorithms plays an important role in tackling with large datasets. The classical frequent pattern growth(FP-growth) algorithm can produce a large number of conditional pattern trees which made it difficult to mine association rules in are telecommunication environment.In this paper,an algorithm based on layered frequent pattern tree(LFP-tree) is proposed for mining frequent patterns. Efficiency of this alagorithm is achieved with following techniques:1) All the frequent patterns are condensed into a layered structure,which can save memory time but also be very useful for updating the alarm databases.2) Each alarm item can be viewed as a triple,in which t is a Boolean vaviable that shows the item frequent or not.3) Deleting infrequent items with dynamic pruning can avoid produce conditional pattern sets. Simulation and analysis of algorithm show that it is a valid method with better time and space efficiency,which is adapted to mine association rules in telecommunication alarm correlation analysis.

  18. Threshold-Based Shortest Path Query over Large Correlated Uncertain Graphs

    Institute of Scientific and Technical Information of China (English)

    成雨蓉; 袁野; 陈雷; 王国仁

    2015-01-01

    With the popularity of uncertain data, queries over uncertain graphs have become a hot topic in the database community. As one of the important queries, the shortest path query over an uncertain graph has attracted much attention of researchers due to its wide applications. Although there are some efficient solutions addressing this problem, all existing models ignore an important property existing in uncertain graphs: the correlation among the edges sharing the same vertex. In this paper, we apply Markov network to model the hidden correlation in uncertain graphs and compute the shortest path. Unfortunately, calculating the shortest path and corresponding probability over uncertain graphs modeled by Markov networks is a #P-hard problem. Thus, we propose a filtering-and-verification framework to accelerate the queries. In the filtering phase, we design a probabilistic shortest path index based on vertex cuts and blocks of a graph. We find a series of upper bounds and prune the vertices and edges whose upper bounds of the shortest path probability are lower than the threshold. By carefully picking up the blocks and vertex cuts, the index is optimized to have the maximum pruning capability, so that we can filter a large number of vertices which make no contribution to the final shortest path query results. In the verification phase, we develop an efficient sampling algorithm to determine the final query answers. Finally, we verify the efficiency and effectiveness of our solutions with extensive experiments.

  19. Utra-bright compact sources of correlated photons based on SPDC in periodically-poled KTP

    Science.gov (United States)

    Beausoleil, Ray; Fiorentino, Marco; Spillane, Sean; Roberts, Tony; Battle, Phil; Munroe, Mark

    2007-05-01

    Photon pairs generated using spontaneous parametric down- conversion (SPDC) have been a central ingredient for a number of quantum optics experiments ranging from the generation of entanglement to demonstrations of quantum information processing protocols. The flux of pairs generated by SPDC sources has been steadily growing over the years opening the door to practical applications of correlated and entangled photon pairs. SPDC sources based on periodically poled waveguides have shown a great potential to generate large numbers of correlated pairs with a few μW of pump. These works, however, lack a clear explanation of the increased pair rate in waveguides and do not directly compare the waveguide result with bulk. Na"ively, field confinement in waveguides is not expected to enhance pair generation rate, since SPDC is a scattering phenomenon that only involves one pump photon and therefore does not benefit from higher photon densities created by focussing. In this talk we present a theoretical and experimental comparison of spontaneous parametric down-conversion in periodically poled waveguides and bulk KTP crystals. We measured a waveguide pair generation rate of 2.9 .10^6 pairs/s per mW of pump in a 1-nm band: more than 50 times higher than the bulk crystal generation rate. To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2007.NWS07.E3.4

  20. A Multi-Label Classification Approach Based on Correlations Among Labels

    Directory of Open Access Journals (Sweden)

    Raed Alazaidah

    2015-02-01

    Full Text Available Multi label classification is concerned with learning from a set of instances that are associated with a set of labels, that is, an instance could be associated with multiple labels at the same time. This task occurs frequently in application areas like text categorization, multimedia classification, bioinformatics, protein function classification and semantic scene classification. Current multi-label classification methods could be divided into two categories. The first is called problem transformation methods, which transform multi-label classification problem into single label classification problem, and then apply any single label classifier to solve the problem. The second category is called algorithm adaptation methods, which adapt an existing single label classification algorithm to handle multi-label data. In this paper, we propose a multi-label classification approach based on correlations among labels that use both problem transformation methods and algorithm adaptation methods. The approach begins with transforming multi-label dataset into a single label dataset using least frequent label criteria, and then applies the PART algorithm on the transformed dataset. The output of the approach is multi-labels rules. The approach also tries to get benefit from positive correlations among labels using predictive Apriori algorithm. The proposed approach has been evaluated using two multi-label datasets named (Emotions and Yeast and three evaluation measures (Accuracy, Hamming Loss, and Harmonic Mean. The experiments showed that the proposed approach has a fair accuracy in comparison to other related methods.

  1. Characterization of calcium and zinc spatial distributions at the fibrocartilage zone of bone–tendon junction by synchrotron radiation-based micro X-ray fluorescence analysis combined with backscattered electron imaging

    International Nuclear Information System (INIS)

    Tendon attaches to bone through a functionally graded fibrocartilage zone, including uncalcified fibrocartilage (UF), tidemark (TM) and calcified fibrocartilage (CF). This transition zone plays a pivotal role in relaxing load transfer between tendon and bone, and serves as a boundary between otherwise structurally and functionally distinct tissue types. Calcium and zinc are believed to play important roles in the normal growth, mineralization, and repair of the fibrocartilage zone of bone–tendon junction (BTJ). However, spatial distributions of calcium and zinc at the fibrocartilage zone of BTJ and their distribution–function relationship are not totally understood. Thus, synchrotron radiation-based micro X-ray fluorescence analysis (SR-μXRF) in combination with backscattered electron imaging (BEI) was employed to characterize the distributions of calcium and zinc at the fibrocartilage zone of rabbit patella–patellar tendon complex (PPTC). For the first time, the unique distributions of calcium and zinc at the fibrocartilage zone of the PPTC were clearly mapped by this method. The distributions of calcium and zinc at the fibrocartilage zone of the PPTC were inhomogeneous. A significant accumulation of zinc was exhibited in the transition region between UF and CF. The highest zinc content (3.17 times of that of patellar tendon) was found in the TM of fibrocartilage zone. The calcium content began to increase near the TM and increased exponentially across the calcified fibrocartilage region towards the patella. The highest calcium content (43.14 times of that of patellar tendon) was in the transitional zone of calcified fibrocartilage region and the patella, approximately 69 μm from the location with the highest zinc content. This study indicated, for the first time, that there is a differential distribution of calcium and zinc at the fibrocartilage zone of PPTC. These observations reveal new insights into region-dependent changes across the fibrocartilage

  2. Characterization of calcium and zinc spatial distributions at the fibrocartilage zone of bone–tendon junction by synchrotron radiation-based micro X-ray fluorescence analysis combined with backscattered electron imaging

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Hongbin; Chen, Can; Wang, Zhanwen; Qu, Jin; Xu, Daqi [Department of Sports Medicine, Research Center of Sports Medicine, Xiangya Hospital, Central South University, Changsha 410008 (China); Wu, Tianding; Cao, Yong [Department of Spine Surgery, Xiangya Hospital, Central South University, Changsha 410008 (China); Zhou, Jingyong; Zheng, Cheng [Department of Sports Medicine, Research Center of Sports Medicine, Xiangya Hospital, Central South University, Changsha 410008 (China); Hu, Jianzhong, E-mail: jianzhonghu@hotmail.com [Department of Sports Medicine, Research Center of Sports Medicine, Xiangya Hospital, Central South University, Changsha 410008 (China); Department of Spine Surgery, Xiangya Hospital, Central South University, Changsha 410008 (China)

    2015-09-01

    Tendon attaches to bone through a functionally graded fibrocartilage zone, including uncalcified fibrocartilage (UF), tidemark (TM) and calcified fibrocartilage (CF). This transition zone plays a pivotal role in relaxing load transfer between tendon and bone, and serves as a boundary between otherwise structurally and functionally distinct tissue types. Calcium and zinc are believed to play important roles in the normal growth, mineralization, and repair of the fibrocartilage zone of bone–tendon junction (BTJ). However, spatial distributions of calcium and zinc at the fibrocartilage zone of BTJ and their distribution–function relationship are not totally understood. Thus, synchrotron radiation-based micro X-ray fluorescence analysis (SR-μXRF) in combination with backscattered electron imaging (BEI) was employed to characterize the distributions of calcium and zinc at the fibrocartilage zone of rabbit patella–patellar tendon complex (PPTC). For the first time, the unique distributions of calcium and zinc at the fibrocartilage zone of the PPTC were clearly mapped by this method. The distributions of calcium and zinc at the fibrocartilage zone of the PPTC were inhomogeneous. A significant accumulation of zinc was exhibited in the transition region between UF and CF. The highest zinc content (3.17 times of that of patellar tendon) was found in the TM of fibrocartilage zone. The calcium content began to increase near the TM and increased exponentially across the calcified fibrocartilage region towards the patella. The highest calcium content (43.14 times of that of patellar tendon) was in the transitional zone of calcified fibrocartilage region and the patella, approximately 69 μm from the location with the highest zinc content. This study indicated, for the first time, that there is a differential distribution of calcium and zinc at the fibrocartilage zone of PPTC. These observations reveal new insights into region-dependent changes across the fibrocartilage

  3. Correlation between voxel based morphometry and manual volumetry in magnetic resonance images of the human brain

    Directory of Open Access Journals (Sweden)

    Ricardo R. Uchida

    2008-03-01

    Full Text Available This is a comparative study between manual volumetry (MV and voxel based morphometry (VBM as methods of evaluating the volume of brain structures in magnetic resonance images. The volumes of the hippocampus and the amygdala of 16 panic disorder patients and 16 healthy controls measured through MV were correlated with the volumes of gray matter estimated by optimized modulated VBM. The chosen structures are composed almost exclusively of gray matter. Using a 4 mm Gaussian filter, statistically significant clusters were found bilaterally in the hippocampus and in the right amygdala in the statistical parametric map correlating with the respective manual volume. With the conventional 12 mm filter,a significant correlation was found only for the right hippocampus. Therefore,narrowfilters increase the sensitivity of the correlation procedure, especially when small brain structures are analyzed. The two techniques seem to consistently measure structural volume.Trata-se de estudo comparativo entre a volumetria manual(VM e a morfometria baseada no vóxel (MBV, como métodos de avaliação do volume de estruturas cerebrais. Os volumes do hipocampo e da amídala de 16 pacientes de pânico e 16 controles sadios medidos através da VM foram correlacionados com os volumes de matéria cinzenta estimados pela MBV.As estruturas escolhidas são constituídas quase exclusivamente de matéria cinzenta. Utilizando um filtro Gaussiano de 4 mm, encontram-se, bilateralmente, aglomerados significativos de correlação nas duas estruturas no mapa estatístico paramétrico, correspondendo ao respectivo volume manual. Com o filtro convencional de 12 mm, apenas uma correlação significativa foi encontrada no hipocampo direito. Portanto, filtros estreitos aumentam a sensibilidade do procedimento de correlação,especialmente quando estruturas pequenas são analisadas. Ambas as técnicas parecem medir consistentemente o volume estrutural.

  4. An Extreme-Value Approach for Testing the Equality of Large U-Statistic Based Correlation Matrices

    OpenAIRE

    Zhou, Cheng; Han, Fang; Zhang, Xinsheng; Liu, Han

    2015-01-01

    There has been an increasing interest in testing the equality of large Pearson's correlation matrices. However, in many applications it is more important to test the equality of large rank-based correlation matrices since they are more robust to outliers and nonlinearity. Unlike the Pearson's case, testing the equality of large rank-based statistics has not been well explored and requires us to develop new methods and theory. In this paper, we provide a framework for testing the equality of t...

  5. Automatic Kappa Angle Estimation for Air Photos Based on Phase Only Correlation

    Science.gov (United States)

    Xiong, Z.; Stanley, D.; Xin, Y.

    2016-06-01

    The approximate value of exterior orientation parameters is needed for air photo bundle adjustment. Usually the air borne GPS/IMU can provide the initial value for the camera position and attitude angle. However, in some cases, the camera's attitude angle is not available due to lack of IMU or other reasons. In this case, the kappa angle needs to be estimated for each photo before bundle adjustment. The kappa angle can be obtained from the Ground Control Points (GCPs) in the photo. Unfortunately it is not the case that enough GCPs are always available. In order to overcome this problem, an algorithm is developed to automatically estimate the kappa angle for air photos based on phase only correlation technique. This function has been embedded in PCI software. Extensive experiments show that this algorithm is fast, reliable, and stable.

  6. Sequential backbone assignment based on dipolar amide-to-amide correlation experiments

    Energy Technology Data Exchange (ETDEWEB)

    Xiang, ShengQi; Grohe, Kristof; Rovó, Petra; Vasa, Suresh Kumar; Giller, Karin; Becker, Stefan; Linser, Rasmus, E-mail: rali@nmr.mpibpc.mpg.de [Max Planck Institute for Biophysical Chemistry, Department for NMR-Based Structural Biology (Germany)

    2015-07-15

    Proton detection in solid-state NMR has seen a tremendous increase in popularity in the last years. New experimental techniques allow to exploit protons as an additional source of information on structure, dynamics, and protein interactions with their surroundings. In addition, sensitivity is mostly improved and ambiguity in assignment experiments reduced. We show here that, in the solid state, sequential amide-to-amide correlations turn out to be an excellent, complementary way to exploit amide shifts for unambiguous backbone assignment. For a general assessment, we compare amide-to-amide experiments with the more common {sup 13}C-shift-based methods. Exploiting efficient CP magnetization transfers rather than less efficient INEPT periods, our results suggest that the approach is very feasible for solid-state NMR.

  7. Organelle proteomics by label-free and SILAC-based protein correlation profiling

    DEFF Research Database (Denmark)

    Dengjel, Joern; Jakobsen, Lis; Andersen, Jens S.

    2010-01-01

    The ability to purify cell organelles and protein complexes on a large scale, combined with advances in protein identification using mass spectrometry, has provided a wealth of information regarding protein localization and function. A major challenge in these studies has been the ability...... to identify bona fide organelle components from a background of co-purifying contaminants because none of the available biochemical purification protocols afford pure preparations. Since this situation is unlikely to change alternative strategies have been devised to meet this challenge by making use...... of the information inherent in the fractionation profile of organelles isolated by density gradient centrifugation. In this chapter we describe strategies based on protein correlation profiling and quantitative mass spectrometry to sort out likely candidates. The organelle inventories defined by these methods...

  8. ESTIMATION OF THE NUMBER OF CORRELATED SOURCES WITH COMMON FREQUENCIES BASED ON POWER SPECTRAL DENSITY

    Institute of Scientific and Technical Information of China (English)

    LI Ning; SHI Tielin

    2007-01-01

    Blind source Separation and estimation of the number of sources usually demand that the number of sensors should be greater than or equal to that of the sources, which, however, is very difficult to satisfy for the complex Systems. A new estimating method based on power spectral density (PSD) is presented. When the relation between the number of sensors and that of sources is unknown, the PSD matrix is first obtained by the ratio of PSD of the observation signals, and then the bound of the number of correlated sources with common frequencies can be estimated by comparing every column vector of PSD matrix. The effectiveness of the proposed method is verified by theoretical analysis and experiments, and the influence of noise on the estimation of number of source is simulated.

  9. Correlation of weight-based objectifying experiences with depression and eating disorder in overweight women

    Directory of Open Access Journals (Sweden)

    Leila Khabir

    2015-06-01

    Full Text Available Background: This study was carried out to investigate the correlation of self-objectification, internalized weight bias and body image concern with depression and eating disorder Methods: A total of 200 female students with overweight and obesity were selected using convenience random sampling among female students with overweight and obesity referring to Shiraz sport clubs in 2013. They responded to Stigmatizing Situations Inventory (SSI, Trait Self- Objectification Questionnaire (TSOQ, Weight Bias Internalization Scale (WBIS, Body Image Concern Inventory (BICI, Center for Epidemiological Studies- Depression Scale (CES-D and Eating Disorder Diagnostic Scale (EDDS. Data were analyzed by structural equation modeling (SEM. Results: Result showed that self-objectification, internalized weight bias and body image concern can mediate the relationship of weight-based objectifying experiences with depression and eating disorder. Conclusion: The findings of this study showed that fitness index of the proposed model can acceptably fit the data.

  10. Asymmetric Sub-Reflectors for Spherical Antennas and Interferometric Observations with an FPGA-Based Correlator

    Science.gov (United States)

    Takeuchi, Hiroshi; Kuniyoshi, Masaya; Daishido, Tsuneaki; Asuma, Kuniyuki; Matsumura, Nobuo; Takefuji, Kazuhiro; Niinuma, Kotaro; Ichikawa, Hajime; Okubo, Riki; Sawano, Akihiro; Yoshimura, Naoya; Fujii, Fumiyuki; Mizuno, Keiju; Akamine, Yukinori

    2005-10-01

    The Nasu Radio Interferometer, consisting of eight equally spaced, 20-m diameter fixed spherical antennas, was developed for the purpose of surveying unknown variable radio sources at 1.4GHz. An asymmetrical Gregorian sub-reflector was designed and installed on each antenna for the purpose of correcting aberrations caused by the spherical reflector. The total collecting area is 2512m2 and the field-of-view of each antenna is 0.°6 × 0.°6. In survey observations a spatial-fast Fourier-transform (FFT)-type multi-beam system will be used. We report on the design of spherical reflectors and a digital back-end system, the basic principle of spatial-FFT image forming, and a result of interferometric observations with an FPGA-based digital correlator.

  11. Informatics-Based Energy Fitting Scheme for Correlation Energy at Complete Basis Set Limit.

    Science.gov (United States)

    Seino, Junji; Nakai, Hiromi

    2016-09-30

    Energy fitting schemes based on informatics techniques using hierarchical basis sets with small cardinal numbers were numerically investigated to estimate correlation energies at the complete basis set limits. Numerical validations confirmed that the conventional two-point extrapolation models can be unified into a simple formula with optimal parameters obtained by the same test sets. The extrapolation model was extended to two-point fitting models by a relaxation of the relationship between the extrapolation coefficients or a change of the fitting formula. Furthermore, n-scheme fitting models were developed by the combinations of results calculated at several theory levels and basis sets to compensate for the deficiencies in the fitting model at one level of theory. Systematic assessments on the Gaussian-3X and Gaussian-2 sets revealed that the fitting models drastically reduced errors with equal or smaller computational effort. © 2016 Wiley Periodicals, Inc. PMID:27454327

  12. Recognition of Emotions using Energy Based Bimodal Information Fusion and Correlation

    Directory of Open Access Journals (Sweden)

    Krishna Asawa

    2014-09-01

    Full Text Available Multi-sensor information fusion is a rapidly developing research area which forms the backbone of numerous essential technologies such as intelligent robotic control, sensor networks, video and image processing and many more. In this paper, we have developed a novel technique to analyze and correlate human emotions expressed in voice tone & facial expression. Audio and video streams captured to populate audio and video bimodal data sets to sense the expressed emotions in voice tone and facial expression respectively. An energy based mapping is being done to overcome the inherent heterogeneity of the recorded bi-modal signal. The fusion process uses sampled and mapped energy signal of both modalities’s data stream and further recognize the overall emotional component using Support Vector Machine (SVM classifier with the accuracy 93.06%

  13. Spatial Correlation Based Low Energy Aware Clustering (LEACH in a Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Floriano De Rango

    2015-01-01

    Full Text Available In this paper, an enhanced Low Energy Aware Cluster Head (LEACH protocol is proposed. It applies aggregation strategies in the area monitored by sensor nodes to reduce the number of reports sent to sink and to save energy. The basic idea is to weight the information sensed by sensors based on the distortion area in order to estimate better the event at the sink node. This approach seeks to exploit the spatial correlation among nodes and among clusters to assign different importance to the information aggregated and forwarded by the cluster head nodes. A multi-zone monitoring related to clusters is proposed, and a dynamic weights management is presented to consider distortion at cluster level introduced in the event estimation. A mathematical formulation of the problem and the proposal to weight space and data information is led out. Simulation campaigns in Matlab show the effectiveness of the event estimation in terms of event estimation distortion and network lifetime.

  14. Hydrogen Molecule Dissociation Curve with Functionals Based on the Strictly Correlated Regime.

    Science.gov (United States)

    Vuckovic, Stefan; Wagner, Lucas O; Mirtschink, André; Gori-Giorgi, Paola

    2015-07-14

    Using the dual Kantorovich formulation, we compute the strictly correlated electrons (SCE) functional (corresponding to the exact strong-interaction limit of density functional theory) for the hydrogen molecule along the dissociation curve. We use an exact relation between the Kantorovich potential and the optimal map to compute the comotion function, exploring corrections based on it. In particular, we analyze how the SCE functional transforms in an exact way the electron-electron distance into a one-body quantity, a feature that can be exploited to build new approximate functionals. We also show that the dual Kantorovich formulation provides in a natural way the constant in the Kohn-Sham potential recently introduced by Levy and Zahariev [Phys. Rev. Lett. 2014, 113, 113002] for finite systems. PMID:26575752

  15. A Fast LSF Search Algorithm Based on Interframe Correlation in G.723.1

    Directory of Open Access Journals (Sweden)

    Kulkarni Jaydeep P

    2004-01-01

    Full Text Available We explain a time complexity reduction algorithm that improves the line spectral frequencies (LSF search procedure on the unit circle for low bit rate speech codecs. The algorithm is based on strong interframe correlation exhibited by LSFs. The fixed point C code of ITU-T Recommendation G.723.1, which uses the “real root algorithm” was modified and the results were verified on ARM-7TDMI general purpose RISC processor. The algorithm works for all test vectors provided by International Telecommunications Union-Telecommunication (ITU-T as well as real speech. The average time reduction in the search computation was found to be approximately 20%.

  16. Math anxiety: A review of its cognitive consequences, psychophysiological correlates, and brain bases.

    Science.gov (United States)

    Suárez-Pellicioni, Macarena; Núñez-Peña, María Isabel; Colomé, Àngels

    2016-02-01

    A decade has passed since the last published review of math anxiety, which was carried out by Ashcraft and Ridley (2005). Given the considerable interest aroused by this topic in recent years and the growing number of publications related to it, the present article aims to provide a full and updated review of the field, ranging from the initial studies of the impact of math anxiety on numerical cognition, to the latest research exploring its electrophysiological correlates and brain bases from a cognitive neuroscience perspective. Finally, this review describes the factors and mechanisms that have been claimed to play a role in the origins and/or maintenance of math anxiety, and it examines in detail the main explanations proposed to account for the negative effects of math anxiety on performance: competition for working memory resources, a deficit in a low-level numerical representation, and inhibition/attentional control deficit.

  17. Effects of Web Based Inquiry Science Environment on Cognitive Outcomes in Biological Science in Correlation to Emotional Intelligence

    Science.gov (United States)

    Manoj, T. I.; Devanathan, S.

    2010-01-01

    This research study is the report of an experiment conducted to find out the effects of web based inquiry science environment on cognitive outcomes in Biological science in correlation to Emotional intelligence. Web based inquiry science environment (WISE) provides a platform for creating inquiry-based science projects for students to work…

  18. First principle nonlinear quantum dynamics using a correlation-based von Neumann entropy

    Science.gov (United States)

    Westermann, Till; Manthe, Uwe

    2012-05-01

    A new concept to describe the quantum dynamics in complex systems is suggested. It extends established schemes based on the Dirac-Frenkel variation principle, e.g., the multi-configurational time-dependent Hartree (MCTDH) approach. The concept is based on a correlation-based von Neumann entropy (CvN-entropy) definition measuring the complexity of the wavefunction. Equations of motion are derived using a CvN-entropy constraint in the variational principle and result in a generally applicable effective Hamiltonian. It consists of the standard Hamilton operator and an additional nonlinear operator which limits the complexity of the wavefunction. Effectively, this nonlinear operator absorbs complex structures which are emerging in the wavefunction and allows one to introduce non-norm conserving equations of motion. Important aspects of the new concept are outlined studying the wave packet propagation on the diabatic B2 potential energy surfaces of NO2. First, it is demonstrated that during standard wave packet propagation the CvN-entropy increases strongly with time roughly independent of the coordinate systems employed. Second, one finds that employing CvN-entropy constrained MCTDH propagation yields improved wave function accuracy on longer time scales while compromising on the short time accuracy. Third, the loss of the wavefunction's norm is directly related to the overlap with the exact wavefunction. This provides an error estimate available without knowing an exact reference.

  19. Investigation of hyperfine interactions in DNA nitrogenous bases using perturbed angular correlation spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Andreia dos Santos; Carbonari, Artur Wilson; Lapolli, Andre Luis; Saxena, Rajendra Narain [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Saitovitch, Henrique, E-mail: asilva@usp.br [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil)

    2013-07-01

    Perturbed γγ angular correlations (PAC) spectroscopy has been used to study the DNA nitrogenous bases (adenine, cytosine, guanine, thymine), using {sup 111}In→{sup 111}Cd and {sup 111m}Cd→{sup 111}Cd probe nuclei. One of the advantages of applying PAC technique to biological molecules is that the experiments can be carried out on molecules in aqueous solution [1], approaching the function of molecules under conditions that are close to in vivo conditions. The measurements were carried out for DNA nitrogenous bases molecules at 295 K and 77 K in order to investigate dynamic and static hyperfine interactions, respectively. The interpretation of the results was based on the measurements of dynamic interaction characterized by the decay constant from which valuable information on the macroscopic behavior of the molecules was obtained [2; 3]. On the other hand, PAC measurements at low temperature showed interaction frequency (ν{sub Q}), asymmetry parameter (η) and the distribution of the quadrupole frequency (δ). These parameters provide a local microscopic description of the chemical environment in the neighborhood of the probe nuclei. Results showed differences in the hyperfine interactions of probe nuclei bound to the studied biomolecules. Such differences were observed by variations in the hyperfine parameters, which depended on the type of biomolecule and the results also showed that the probe nuclei bounded at the molecules in some cases and at others did not. (author)

  20. Noise-induced bias for convolution-based interpolation in digital image correlation.

    Science.gov (United States)

    Su, Yong; Zhang, Qingchuan; Gao, Zeren; Xu, Xiaohai

    2016-01-25

    In digital image correlation (DIC), the noise-induced bias is significant if the noise level is high or the contrast of the image is low. However, existing methods for the estimation of the noise-induced bias are merely applicable to traditional interpolation methods such as linear and cubic interpolation, but are not applicable to generalized interpolation methods such as BSpline and OMOMS. Both traditional interpolation and generalized interpolation belong to convolution-based interpolation. Considering the widely use of generalized interpolation, this paper presents a theoretical analysis of noise-induced bias for convolution-based interpolation. A sinusoidal approximate formula for noise-induced bias is derived; this formula motivates an estimating strategy which is with speed, ease, and accuracy; furthermore, based on this formula, the mechanism of sophisticated interpolation methods generally reducing noise-induced bias is revealed. The validity of the theoretical analysis is established by both numerical simulations and actual subpixel translation experiment. Compared to existing methods, formulae provided by this paper are simpler, briefer, and more general. In addition, a more intuitionistic explanation of the cause of noise-induced bias is provided by quantitatively characterized the position-dependence of noise variability in the spatial domain. PMID:26832501

  1. The Influence of Dentine on the pH of Calcium Hydroxide, Chlorhexidine Gel, and Experimental Bioactive Glass-Based Root Canal Medicament

    OpenAIRE

    Ceci Nunes Carvalho; Laila Gonzales Freire; Alexandre Pinheiro Lima de Carvalho; Evandro Luiz Siqueira; José Bauer; Giovana Cunha Gritti; Juliana Pereira de Souza; Giulio Gavini

    2015-01-01

    Objectives. To evaluate the influence of dentine on the pH of different medications in standardized simulated canals. Materials and Methods. Forty resin blocks were divided into groups with and without dentine powder, as follows: 2% chlorhexidine gel; 2% chlorhexidine gel associated with calcium hydroxide PA; calcium hydroxide PA delivered in propylene glycol 600; and NPG delivered in distilled water. The dentine powder was obtained from the root dentine of bovine teeth and added to the medic...

  2. Ion Beam Analysis Of Silicon-Based Surfaces And Correlation With Surface Energy Measurements

    Science.gov (United States)

    Xing, Qian; Herbots, N.; Hart, M.; Bradley, J. D.; Wilkens, B. J.; Sell, D. A.; Sell, Clive H.; Kwong, Henry Mark; Culbertson, R. J.; Whaley, S. D.

    2011-06-01

    The water affinity of Si-based surfaces is quantified by contact angle measurement and surface free energy to explain hydrophobic or hydrophilic behavior of silicone, silicates, and silicon surfaces. Surface defects such as dangling bonds, surface free energy including Lewis acid-base and Lifshitz-van der Waals components are discussed. Water nucleation and condensation is further explained by surface topography. Tapping mode atomic force microscopy (TMAFM) provides statistical analysis of the topography of these Si-based surfaces. The correlation of the above two characteristics describes the behavior of water condensation at Si-based surfaces. Surface root mean square roughness increasing from several Å to several nm is found to provide nucleation sites that expedite water condensation visibly for silica and silicone. Hydrophilic surfaces have a condensation pattern that forms puddles of water while hydrophobic surfaces form water beads. Polymer adsorption on these surfaces alters the water affinity as well as the surface topography, and therefore controls condensation on Si-based surfaces including silicone intraocular lens (IOL). The polymer film is characterized by Rutherford backscattering spectrometry (RBS) in conjunction with 4.265 MeV 12C(α, α)12C, 3.045 MeV 16O(α,α)16O nuclear resonance scattering (NRS), and 2.8 MeV elastic recoil detection (ERD) of hydrogen for high resolution composition and areal density measurements. The areal density of hydroxypropyl methylcellulose (HPMC) film ranges from 1018 atom/cm2 to 1019 atom/cm2 gives the silica or silicone surface a roughness of several Å and a wavelength of 0.16±0.02 μm, and prevents fogging by forming a complete wetting layer during water condensation.

  3. Evaluation of palm oil mill fly ash supported calcium oxide as a heterogeneous base catalyst in biodiesel synthesis from crude palm oil

    International Nuclear Information System (INIS)

    Highlights: • Calcination temperature is an important influencing factor in catalytic activity. • The optimum calcination conditions were determined to be 850 °C for 2 h. • Maximum yield of 79.8% and FAME conversion of 97.1% was achieved. • Kinetic data fitted the pseudo-first order model and the Ea was 42.56 kJ mol−1. • The novel catalyst can be reused for 3 cycles with a final biodiesel yield of 60%. - Abstract: A palm oil mill fly ash supported calcium oxide (CaO) catalyst was developed to be used as a heterogeneous base catalyst in biodiesel synthesis from crude palm oil (CPO). The catalyst preparation procedure was optimised in terms of final calcination temperature and duration. The optimum catalyst preparation conditions were determined as final calcination at 850 °C for 2 h with 45 wt.% loading of calcined calcium carbonate (CaCO3). A maximum biodiesel yield of 75.73% was achieved for this catalyst under fixed transesterification conditions. Characterisation tests showed that the catalyst had higher surface area and basic sites which favoured transesterification. The effects of catalyst loading, methanol to oil molar ratio, reaction temperature and reaction time on biodiesel yield and fatty acid methyl ester (FAME) conversion were also investigated. It was determined that transesterification conditions of 6 wt.% catalyst loading, 12:1 methanol to oil molar ratio, 45 °C reaction temperature, 3 h reaction time and 700 rpm stirring speed resulted in biodiesel yield and FAME conversion of 79.76% and 97.09%, respectively. Experimental kinetic data obtained from the heterogeneous transesterification reactions fitted the pseudo-first order kinetic model. The activation energy (Ea) of the reaction was calculated to be 42.56 kJ mol−1. Key physicochemical properties of the produced biodiesel were measured and found to be within the limits set by EN 14214. The developed catalyst could feasibly be used up to three consecutive cycles after regeneration

  4. [Calcium pyrophosphate dihydrate deposition disease].

    Science.gov (United States)

    Koitschev, C; Kaiserling, E; Koitschev, A

    2003-08-01

    Calcium pyrophosphate dihydrate deposition disease (CPPD) of the temporomandibular joint is rare. The disorder is characterized by the presence of crystal deposits within the affected joint. The deposition of crystals in adjacent soft tissue may lead to the formation of pseudotumors. This form of the disease is called tophaceous pseudogout and typically affects the temporomandibular joint. It is difficult to differentiate the disease, particularly from malignant tumors, on the clinical and radiographic findings alone. The diagnosis is based on histological identification of the calcium pyrophosphate crystals. We present an unusually advanced case of tophaceous pseudogout of the temporomandibular joint. The etiology, clinical and diagnostic criteria as well as treatment options are discussed on the basis of our own experience and a review of the literature. PMID:12942180

  5. Analysis and design of a calcium-based sulfur sorbent for applications in integrated gasification combined cycle energy systems

    Science.gov (United States)

    Hasler, David Johann Ludwig

    The reactivity of various Ca-based sorbent materials in pelletized form with H2S or CO2 was investigated at high temperatures (750--880°C). An extensive study was conducted to compare the performance of sorbent pellets derived from plaster of Paris and limestone. Multicycle absorption and regeneration tests showed that plaster-based pellets out performed the limestone-based pellets primarily due to a higher surface area and mesoporosity. The effect of pore-modifiers on the reactivity of limestone with H 2S was investigated by incorporating additives such as cornstarch, graphite and polyvinylalcohol (PVA) in the sorbent. Multicycle sulfidation and regeneration tests of the modified sorbent showed that starch did not improve the reactivity of the limestone, graphite reduced the reactivity, while PVA improved it. The effect of the chemical additives MgO and SrO on the performance of CaO-based sorbent pellets was investigated. The effect of MgO was tested by starting with materials that contained MgCO3 in a natural form, such as dolomite. The effect of SrO was tested by starting with SrCO 3 either co-precipitated with CaCO3 or by wet-mixing SrCO 3 with limestone in slurry form. The MgO was found to improve the thermal stability of the CaO-based sorbent but lowered the overall absorption capacity of the material when reacted with CO2 or H2S, while SrO decreased the thermal stability of the sorbent when it was reacted with CO2; no absorption tests were run with H2S. A study of the performance of pelletized CaO-based cores coated with a refractory material such as alumina and limestone or alumina and kaolin was conducted. The reactivity of the core and shell pellets with H2S was determined. The strength and durability of the pellets were determined by using crushing strength analysis and abrasion resistance tests. Pellets coated with either alumina and limestone or alumina and kaolin proved to be strong and adequate for use in industrial reactors. A semi

  6. Correlations between Energy and Displacement Demands for Performance-Based Seismic Engineering

    Science.gov (United States)

    Mollaioli, Fabrizio; Bruno, Silvia; Decanini, Luis; Saragoni, Rodolfo

    2011-01-01

    The development of a scientific framework for performance-based seismic engineering requires, among other steps, the evaluation of ground motion intensity measures at a site and the characterization of their relationship with suitable engineering demand parameters (EDPs) which describe the performance of a structure. In order to be able to predict the damage resulting from earthquake ground motions in a structural system, it is first necessary to properly identify ground motion parameters that are well correlated with structural response and, in turn, with damage. Since structural damage during an earthquake ground motion may be due to excessive deformation or to cumulative cyclic damage, reliable methods for estimating displacement demands on structures are needed. Even though the seismic performance is directly related to the global and local deformations of the structure, energy-based methodologies appear more helpful in concept, as they permit a rational assessment of the energy absorption and dissipation mechanisms that can be effectively accomplished to balance the energy imparted to the structure. Moreover, energy-based parameters are directly related to cycles of response of the structure and, therefore, they can implicitly capture the effect of ground motion duration, which is ignored by conventional spectral parameters. Therefore, the identification of reliable relationships between energy and displacement demands represents a fundamental issue in both the development of more reliable seismic code provisions and the evaluation of seismic vulnerability aimed at the upgrading of existing hazardous facilities. As these two aspects could become consistently integrated within a performance-based seismic design methodology, understanding how input and dissipated energy are correlated with displacement demands emerges as a decisive prerequisite. The aim of the present study is the establishment of functional relationships between input and dissipated energy

  7. Assessment of high performance concrete containing fly ash and calcium nitrite based corrosion inhibitor as a mean to prevent the corrosion of reinforcing steel

    International Nuclear Information System (INIS)

    This research analyses the effectiveness of the water-to-cement ratio (w/c), fly ash and a calcium nitrite based corrosion inhibitor to prevent the corrosion of reinforcing steel embedded in high performance concrete. The interactive effect between the inhibitor and fly ash was evaluated because the occurrence of a negative effect when both ingredients are added together in a concrete mixture has been reported. All the concrete mixtures studied in this investigation had 8.2% of silica fume. Twenty seven prismatic concrete specimens were fabricated with dimensions of 55 × 230 × 300 mm each containing two steel rods embedded for the purpose of corrosion monitoring. The specimens were exposed to a simulated marine environment with two daily cycles of wetting and drying for one year. To evaluate the deterioration of the specimens corrosion potentials and linear polarization resistance tests were carried out. The results indicate that the use of a low w/c, the addition of fly ash and the addition of the corrosion inhibitor contributed to the reduction of the corrosion of steel in the concrete specimens. The results further suggest that the combination of fly ash and corrosion inhibitor does not promote the deterioration of the concrete matrix

  8. Effect of particle size of calcium phosphate based bioceramic drug delivery carrier on the release kinetics of ciprofloxacin hydrochloride: an in vitro study

    Science.gov (United States)

    Sasikumar, Swamiappan

    2013-09-01

    Hydroxyapatite (HAP) is the constituent of calcium phosphate based bone cement and it is extensively used as a bone substitute and drug delivery vehicle in various biomedical applications. In the present study we investigated the release kinetics of ciprofloxacin loaded HAP and analyzed its ability to function as a targeted and sustained release drug carrier. Synthesis of HAP was carried out by combustion method using tartaric acid as a fuel and nitric acid as an oxidizer. Powder XRD and FTIR techniques were employed to characterize the phase purity of the drug carrier and to verify the chemical interaction between the drug and carrier. The synthesized powders were sieve separated to make two different drug carriers with different particle sizes and the surface topography of the pellets of the drug carrier was imaged by AFM. Surface area and porosity of the drug carrier was carried out using surface area analyzer. The in-vitro drug release kinetics was performed in simulated body fluid, at 37.3°C. The amount of ciprofloxacin released is measured using UV-visible spectroscopy following the characteristic λ max of 278 nm. The release saturates around 450 h which indicates that it can be used as a targeted and sustained release carrier for bone infections.

  9. Nonlinear Color--Metallicity Relations of Globular Clusters. VI. On Calcium II Triplet Based Metallicities of Globular Clusters in Early-type Galaxies

    CERN Document Server

    Chung, Chul; Lee, Sang-Yoon; Lee, Young-Wook

    2016-01-01

    The metallicity distribution function of globular clusters (GCs) in galaxies is a key to understanding galactic formation and evolution. The calcium II triplet (CaT) index has recently become a popular metal abundance indicator thanks to its sensitivity to GC metallicity. Here we revisit and assess the reliability of CaT as a metallicity indicator using our new stellar population synthesis simulations based on empirical, high-resolution fluxes. The model shows that the CaT strength of old ($>$ 10 Gyr) GCs is proportional to ${\\rm [Fe/H]}$ below $-0.5$. In the modest metal-rich regime, however, CaT does not increase anymore with ${\\rm [Fe/H]}$ due to the little contribution from coolest red giant stars to the CaT absorption. The nonlinear nature of the color--$CaT$ relation is confirmed by the observations of GCs in nearby early-type galaxies. This indicates that the CaT should be used carefully when deriving metallicities of metal-rich stellar populations. Our results offer an explanation for the observed sha...

  10. Assessment of high performance concrete containing fly ash and calcium nitrite based corrosion inhibitor as a mean to prevent the corrosion of reinforcing steel

    Science.gov (United States)

    Montes-García, P.; Jiménez-Quero, V.; López-Calvo, H.

    2015-01-01

    This research analyses the effectiveness of the water-to-cement ratio (w/c), fly ash and a calcium nitrite based corrosion inhibitor to prevent the corrosion of reinforcing steel embedded in high performance concrete. The interactive effect between the inhibitor and fly ash was evaluated because the occurrence of a negative effect when both ingredients are added together in a concrete mixture has been reported. All the concrete mixtures studied in this investigation had 8.2% of silica fume. Twenty seven prismatic concrete specimens were fabricated with dimensions of 55 × 230 × 300 mm each containing two steel rods embedded for the purpose of corrosion monitoring. The specimens were exposed to a simulated marine environment with two daily cycles of wetting and drying for one year. To evaluate the deterioration of the specimens corrosion potentials and linear polarization resistance tests were carried out. The results indicate that the use of a low w/c, the addition of fly ash and the addition of the corrosion inhibitor contributed to the reduction of the corrosion of steel in the concrete specimens. The results further suggest that the combination of fly ash and corrosion inhibitor does not promote the deterioration of the concrete matrix.

  11. 3D fast adaptive correlation imaging for large-scale gravity data based on GPU computation

    Science.gov (United States)

    Chen, Z.; Meng, X.; Guo, L.; Liu, G.

    2011-12-01

    comtinue to perform 3D correlation imaging for the redisual gravity data. After several iterations, we can obtain a satisfactoy results. Newly developed general purpose computing technology from Nvidia GPU (Graphics Processing Unit) has been put into practice and received widespread attention in many areas. Based on the GPU programming mode and two parallel levels, five CPU loops for the main computation of 3D correlation imaging are converted into three loops in GPU kernel functions, thus achieving GPU/CPU collaborative computing. The two inner loops are defined as the dimensions of blocks and the three outer loops are defined as the dimensions of threads, thus realizing the double loop block calculation. Theoretical and real gravity data tests show that results are reliable and the computing time is greatly reduced. Acknowledgments We acknowledge the financial support of Sinoprobe project (201011039 and 201011049-03), the Fundamental Research Funds for the Central Universities (2010ZY26 and 2011PY0183), the National Natural Science Foundation of China (41074095) and the Open Project of State Key Laboratory of Geological Processes and Mineral Resources (GPMR0945).

  12. Correlating multidimensional fetal heart rate variability analysis with acid-base balance at birth

    International Nuclear Information System (INIS)

    Fetal monitoring during labour currently fails to accurately detect acidemia. We developed a method to assess the multidimensional properties of fetal heart rate variability (fHRV) from trans-abdominal fetal electrocardiogram (fECG) during labour. We aimed to assess this novel bioinformatics approach for correlation between fHRV and neonatal pH or base excess (BE) at birth. We enrolled a prospective pilot cohort of uncomplicated singleton pregnancies at 38–42 weeks’ gestation in Milan, Italy, and Liverpool, UK. Fetal monitoring was performed by standard cardiotocography. Simultaneously, with fECG (high sampling frequency) was recorded. To ensure clinician blinding, fECG information was not displayed. Data from the last 60 min preceding onset of second-stage labour were analyzed using clinically validated continuous individualized multiorgan variability analysis (CIMVA) software in 5 min overlapping windows. CIMVA allows simultaneous calculation of 101 fHRV measures across five fHRV signal analysis domains. We validated our mathematical prediction model internally with 80:20 cross-validation split, comparing results to cord pH and BE at birth. The cohort consisted of 60 women with neonatal pH values at birth ranging from 7.44 to 6.99 and BE from −0.3 to −18.7 mmol L−1. Our model predicted pH from 30 fHRV measures (R2 = 0.90, P < 0.001) and BE from 21 fHRV measures (R2 = 0.77, P < 0.001). Novel bioinformatics approach (CIMVA) applied to fHRV derived from trans-abdominal fECG during labor correlated well with acid-base balance at birth. Further refinement and validation in larger cohorts are needed. These new measurements of fHRV might offer a new opportunity to predict fetal acid-base balance at birth. (fast track communication)

  13. Correlation between charge transfer and exchange coupling in carbon-based magnetic materials

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Anh Tuan, E-mail: tuanna@hus.edu.vn [Faculty of Physics, VNU University of Science, 334 Nguyen Trai, Thanh Xuan, Ha Noi (Viet Nam); Science and Technology Department, Vietnam National University, Hanoi, 144 Xuan Thuy, Cau Giay, Hanoi (Viet Nam); Japan Advanced Institute of Science and Technology, 1-1, Asahidai, Nomi, Ishikawa, 923-1292 Japan (Japan); Nguyen, Van Thanh; Nguyen, Huy Sinh [Faculty of Physics, VNU University of Science, 334 Nguyen Trai, Thanh Xuan, Ha Noi (Viet Nam); Pham, Thi Tuan Anh [Faculty of Physics, VNU University of Science, 334 Nguyen Trai, Thanh Xuan, Ha Noi (Viet Nam); Faculty of Science, College of Hai Duong, Nguyen Thi Due, Hai Duong (Viet Nam); Do, Viet Thang [Faculty of Physics, VNU University of Science, 334 Nguyen Trai, Thanh Xuan, Ha Noi (Viet Nam); Faculty of Science, Haiphong University, 171 Phan Dang Luu, Kien An, Hai Phong (Viet Nam); Dam, Hieu Chi [Japan Advanced Institute of Science and Technology, 1-1, Asahidai, Nomi, Ishikawa, 923-1292 Japan (Japan)

    2015-10-15

    Several forms of carbon-based magnetic materials, i.e. single radicals, radical dimers, and alternating stacks of radicals and diamagnetic molecules, have been investigated using density-functional theory with dispersion correction and full geometry optimization. Our calculated results demonstrate that the C{sub 31}H{sub 15} (R{sub 4}) radical has a spin of ½. However, in its [R{sub 4}]{sub 2} dimer structure, the net spin becomes zero due to antiferromagnetic spin-exchange between radicals. To avoid antiferromagnetic spin-exchange of identical face-to-face radicals, eight alternating stacks, R{sub 4}/D{sub 2m}/R{sub 4} (with m = 3-10), were designed. Our calculated results show that charge transfer (Δn) between R{sub 4} radicals and the diamagnetic molecule D{sub 2m} occurs with a mechanism of spin exchange (J) in stacks. The more electrons that transfer from R{sub 4} to D{sub 2m}, the stronger the ferromagnetic spin-exchange in stacks. In addition, our calculated results show that Δn can be tailored by adjusting the electron affinity (E{sub a}) of D{sub 2m}. The correlation between Δn, E{sub a}, m, and J is discussed. These results give some hints for the design of new ferromagnetic carbon-based materials.

  14. Correlation between charge transfer and exchange coupling in carbon-based magnetic materials

    Directory of Open Access Journals (Sweden)

    Anh Tuan Nguyen

    2015-10-01

    Full Text Available Several forms of carbon-based magnetic materials, i.e. single radicals, radical dimers, and alternating stacks of radicals and diamagnetic molecules, have been investigated using density-functional theory with dispersion correction and full geometry optimization. Our calculated results demonstrate that the C31H15 (R4 radical has a spin of ½. However, in its [R4]2 dimer structure, the net spin becomes zero due to antiferromagnetic spin-exchange between radicals. To avoid antiferromagnetic spin-exchange of identical face-to-face radicals, eight alternating stacks, R4/D2m/R4 (with m = 3-10, were designed. Our calculated results show that charge transfer (Δn between R4 radicals and the diamagnetic molecule D2m occurs with a mechanism of spin exchange (J in stacks. The more electrons that transfer from R4 to D2m, the stronger the ferromagnetic spin-exchange in stacks. In addition, our calculated results show that Δn can be tailored by adjusting the electron affinity (Ea of D2m. The correlation between Δn, Ea, m, and J is discussed. These results give some hints for the design of new ferromagnetic carbon-based materials.

  15. Numerical simulation and CFD-Based Correlation of Erosion Threshold Gas Velocity in Pipe Bends

    Directory of Open Access Journals (Sweden)

    K A Ibrahim1

    2010-04-01

    Full Text Available

    This paper presents numerical simulation of sand erosion phenomena in curved ducts. The Eulerian-Lagrangian approach is used to simulate the gas-solid two-phase flow while semi-empirical model is used to calculate the erosion rate. The effect of solid phase on the gas phase is included in the model. The model prediction is validated with the available experimental data and good agreement was obtained. Based on many predictions of the maximum penetration rate, a CFD based correlation is developed to calculate the penetration rate in bends. From this equation a model to predict the erosional velocity was developed. The present results showed that the flow velocity should be decreased as the mass loading ratio, particle size, pipe diameter increase in order to avoid failure.

  16. MRI-based volumetry correlates of autobiographical memory in Alzheimer's disease.

    Directory of Open Access Journals (Sweden)

    Nathalie Philippi

    Full Text Available The aim of the present volumetric study was to explore the neuro-anatomical correlates of autobiographical memory loss in Alzheimer's patients and healthy elderly, in terms of the delay of retention, with a particular interest in the medial temporal lobe structures. Fifteen patients in early stages of the disease and 11 matched control subjects were included in the study. To assess autobiographical memory and the effect of the retention delay, a modified version of the Crovitz test was used according to five periods of life. Autobiographical memory deficits were correlated to local atrophy via structural MRI using Voxel Based Morphometry. We used a 'lateralized index' to compare the relative contribution of hippocampal sub-regions (anterior vs posterior, left vs right according to the different periods of life. Our results confirm the involvement of the hippocampus proper in autobiographical memory retrieval for both recent and very remote encoding periods, with larger aspect for the very remote period on the left side. Contrary to the prominent left-sided involvement for the young adulthood period, the implication of the right hippocampus prevails for the more recent periods and decreases with the remoteness of the memories, which might be associated with the visuo-spatial processing of the memories. Finally, we suggest the existence of a rostrocaudal gradient depending on the retention duration, with left anterior aspects specifically related to retrieval deficits of remote memories from the young adulthood period, whereas posterior aspects would result of simultaneous encoding and/or consolidation and retrieval deficit of more recent memories.

  17. Prediction of altimetric sea level anomalies using time series models based on spatial correlation

    Science.gov (United States)

    Miziński, Bartłomiej; Niedzielski, Tomasz

    2014-05-01

    Sea level anomaly (SLA) times series, which are time-varying gridded data, can be modelled and predicted using time series methods. This approach has been shown to provide accurate forecasts within the Prognocean system, the novel infrastructure for anticipating sea level change designed and built at the University of Wrocław (Poland) which utilizes the real-time SLA data from Archiving, Validation and Interpretation of Satellite Oceanographic data (AVISO). The system runs a few models concurrently, and our ocean prediction experiment includes both uni- and multivariate time series methods. The univariate ones are: extrapolation of polynomial-harmonic model (PH), extrapolation of polynomial-harmonic model and autoregressive prediction (PH+AR), extrapolation of polynomial-harmonic model and self-exciting threshold autoregressive prediction (PH+SETAR). The following multivariate methods are used: extrapolation of polynomial-harmonic model and vector autoregressive prediction (PH+VAR), extrapolation of polynomial-harmonic model and generalized space-time autoregressive prediction (PH+GSTAR). As the aforementioned models and the corresponding forecasts are computed in real time, hence independently and in the same computational setting, we are allowed to compare the accuracies offered by the models. The objective of this work is to verify the hypothesis that the multivariate prediction techniques, which make use of cross-correlation and spatial correlation, perform better than the univariate ones. The analysis is based on the daily-fitted and updated time series models predicting the SLA data (lead time of two weeks) over several months when El Niño/Southern Oscillation (ENSO) was in its neutral state.

  18. Ca analysis: an Excel based program for the analysis of intracellular calcium transients including multiple, simultaneous regression analysis.

    Science.gov (United States)

    Greensmith, David J

    2014-01-01

    Here I present an Excel based program for the analysis of intracellular Ca transients recorded using fluorescent indicators. The program can perform all the necessary steps which convert recorded raw voltage changes into meaningful physiological information. The program performs two fundamental processes. (1) It can prepare the raw signal by several methods. (2) It can then be used to analyze the prepared data to provide information such as absolute intracellular Ca levels. Also, the rates of change of Ca can be measured using multiple, simultaneous regression analysis. I demonstrate that this program performs equally well as commercially available software, but has numerous advantages, namely creating a simplified, self-contained analysis workflow.

  19. Relevant modes selection method based on Spearman correlation coefficient for laser signal denoising using empirical mode decomposition

    Science.gov (United States)

    Duan, Yabo; Song, Chengtian

    2016-10-01

    Empirical mode decomposition (EMD) is a recently proposed nonlinear and nonstationary laser signal denoising method. A noisy signal is broken down using EMD into oscillatory components that are called intrinsic mode functions (IMFs). Thresholding-based denoising and correlation-based partial reconstruction of IMFs are the two main research directions for EMD-based denoising. Similar to other decomposition-based denoising approaches, EMD-based denoising methods require a reliable threshold to determine which IMFs are noise components and which IMFs are noise-free components. In this work, we propose a new approach in which each IMF is first denoised using EMD interval thresholding (EMD-IT), and then a robust thresholding process based on Spearman correlation coefficient is used for relevant modes selection. The proposed method tackles the problem using a thresholding-based denoising approach coupled with partial reconstruction of the relevant IMFs. Other traditional denoising methods, including correlation-based EMD partial reconstruction (EMD-Correlation), discrete Fourier transform and wavelet-based methods, are investigated to provide a comparison with the proposed technique. Simulation and test results demonstrate the superior performance of the proposed method when compared with the other methods.

  20. Validation of a raw data-based synchronization signal (kymogram) for phase-correlated cardiac image reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Ertel, Dirk; Kachelriess, Marc; Kalender, Willi A. [University of Erlangen-Nuernberg, Institute of Medical Physics (IMP), Erlangen (Germany); Pflederer, Tobias; Achenbach, Stephan [University of Erlangen-Nuernberg, Department of Internal Medicine II, Erlangen (Germany); Steffen, Peter [University of Erlangen-Nuernberg, Multimedia Communications and Signal Processing, Erlangen (Germany)

    2008-02-15

    Phase-correlated reconstruction is commonly used in computed tomography (CT)-based cardiac imaging. Alternatively to the commonly used ECG, the raw data-based kymogram function can be used as a synchronization signal. We used raw data of 100 consecutive patient exams to compare the performance of kymogram function to the ECG signal. For objective validation the correlation of the ECG and the kymogram was assessed. Additionally, we performed a double-blinded comparison of ECG-based and kymogram-based phase-correlated images. The two synchronization signals showed good correlation indicated by a mean difference in the detected heart rate of negligible 0.2 bpm. The mean image quality score was 2.0 points for kymogram-correlated images and 2.3 points for ECG-correlated images, respectively (3: best; 0: worst). The kymogram and the ECG provided images adequate for diagnosis for 93 and 97 patients, respectively. For 50% of the datasets the kymogram provided an equivalent or even higher image quality compared with the ECG signal. We conclude that an acceptable image quality can be assured in most cases by the kymogram. Improvements of image quality by the kymogram function were observed in a noticeable number of cases. The kymogram can serve as a backup solution when an ECG is not available or lacking in quality. (orig.)