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Sample records for dos radionuclideos 201tl

  1. Leg arteritis exploration by quantitative muscle scintigraphy with 201Tl

    SciTech Connect

    Robert, J.; Thouvenot, P.; Schmidt, C.; Escanye, J.M.; Schmitt, J.

    1984-10-01

    Detection and localization of peripheral arterial disease was evaluated by an intravenous injection of 201Tl at peak exercise in 18 subjects and at rest in 6 patients. Images of the skull (S), thighs (T), knees (K), calves (C) and feet (F) were obtained at rest or after exercise and stored in a computer. Intraleg (T/K, T/C, T/F), and left to right interleg (TL/TR,...) count ratios were calculated. In addition, all patients were submitted to routine functional tests (walk perimeter, serial local arterial blood pressure measurement, Strandness test, venous occlusion plethysmography). Correlations between functional tests and the intra and interleg ratios were calculated. After exercise, there is a medium correlation between the tissular blood flow under hyperemia at the calf level and the T/C and C/K ratios. At the calf level a good correlation is obtained for CL/CR and the flux under hyperemia (r = 0.81, P 0.001). A ratio between the counting rates of limb segments after exercise and those of skull was established. The ratios T/S and C/S compared with the systolic pressure index of the most affected limb after a Strandness test give a correlation of 0.72 (P 0.02) for the thigh and of 0.86 (P 0.001) for the calf. For hyperemic flux, the correlation are 0.58 (P 0.005) with T/S and 0.75 (P 0.001) with C/S. In order to find the best quantitative scintigraphic index of the arterial illness, we compared the different ratio values with the distance walked. For T/S we found a relationship very close to a linear one and for C/S a less significant exponential one. Thus, quantitative scintigraphy using 201Tl appears as an accurate method to measure local muscular perfusion deficit in the cases of lower limb arterial disease.

  2. Spontaneous changes in /sup 201/Tl myocardial perfusion imaging after myocardial infarction

    SciTech Connect

    Buda, A.J.; Dubbin, J.D.; MacDonald, I.L.; Strauss, H.D.; Orr, S.A.; Meindok, H.

    1982-12-01

    To examine regional myocardial perfusion after myocardial infarction, 26 patients underwent exercise electrocardiographic testing with /sup 201/Tl myocardial perfusion imaging 3 weeks and 3 months after infarction. At 3 weeks, 9 of 26 patients (35%) had myocardial ischemia by exercise electrocardiographic testing, whereas 18 of 26 (69%) had ischemia by /sup 201/Tl imaging. The /sup 201/Tl scintigrams were scored by dividing each image, in 3 views, into 5 segments, using a 5-point scoring scheme. The exercise /sup 201/Tl score was 44.3 +/- 1.2 and increased to 47.3 +/- 1.2 in the redistribution study (p less than 0.001). Three months after infarction, although there was a significantly greater rate-pressure product which would predict a larger ischemic defect and a decrease in the stress /sup 201/Tl score, the stress score was improved (48.3 +/- 1.1, p less than 0.001). The redistribution score was similar, that is, 48.9 +/- 1.0. The improvement in /sup 201/Tl myocardial perfusion was associated with a loss of stress-induced ischemia in 8 patients (30%). These results indicate that spontaneous improvements in /sup 201/Tl myocardial perfusion imaging may occur after myocardial infarction.

  3. Dipyridamole 201Tl scintigraphy in the evaluation of prognosis after myocardial infarction

    SciTech Connect

    Okada, R.D.; Glover, D.K.; Leppo, J.A. )

    1991-09-01

    Dipyridamole 201Tl imaging has been proposed as an alternative to exercise ECG testing for the prehospital discharge evaluation of patients recovering from myocardial infarction. The rationale is that many postinfarction patients with exercise-induced ischemia experience later cardiac events, and the sensitivity of predischarge exercise ECG testing in patients with multivessel disease ranges from only 45% to 62%. In addition, several groups of investigators have shown the sensitivity of submaximum exercise 201Tl imaging to be less than ideal. This report summarizes the current status of dipyridamole 201Tl imaging in the period of 1-13 days after myocardial infarction. Although the number of studies performed to date is limited, the following conclusions can be drawn: dipyridamole 201Tl imaging after myocardial infarction was associated with no serious side effects, and those present could be quickly reversed with aminophylline; redistribution with dipyridamole 201Tl images definitely correlates with prognosis after uncomplicated myocardial infarction; dipyridamole 201Tl imaging is definitely useful in patients unable to exercise for a variety of reasons; and future studies are definitely indicated to further define the role of dipyridamole 201Tl imaging for assessing prognosis, especially in those patients undergoing interventional therapy after acute myocardial infarction.

  4. Value of planar 201Tl imaging in risk stratification of patients recovering from acute myocardial infarction

    SciTech Connect

    Gibson, R.S.; Watson, D.D. )

    1991-09-01

    Although exercise ECG testing has been shown to have important prognostic value after acute myocardial infarction, exercise 201Tl scintigraphy offers several potential advantages, including: (1) increased sensitivity for detecting residual myocardial ischemia; (2) the ability to localize ischemia to a specific area or areas subtended by a specific coronary artery; (3) the ability to identify exercise-induced left ventricular dysfunction, which is manifested by increased lung uptake or transient left ventricular dilation; and (4) more reliable risk stratification of individual patients. The more optimal prognostic efficiency of 201Tl scintigraphy partially results from the fact that the error rate in falsely classifying patients as low risk is significantly smaller with 201Tl scintigraphy than with stress ECG. Because of these substantial advantages, there seems to be adequate rationale for recommending exercise perfusion imaging rather than exercise ECG alone as the preferred method for evaluating mortality and morbidity risks after acute myocardial infarction.

  5. 201Tl+-labelled Prussian blue nanoparticles as contrast agents for SPECT scintigraphy

    NASA Astrophysics Data System (ADS)

    Perrier, M.; Busson, M.; Massasso, G.; Long, J.; Boudousq, V.; Pouget, J.-P.; Peyrottes, S.; Perigaud, Ch.; Porredon-Guarch, C.; de Lapuente, J.; Borras, M.; Larionova, J.; Guari, Y.

    2014-10-01

    Prussian blue (PB) and its analogues on the nanometric scale are exciting nano-objects that combine the advantages of molecular-based materials and nanochemistry. Herein, we demonstrate that ultra-small PB nanoparticles of 2-3 nm can be easily labelled with radioactive 201Tl+ to obtain new nanoprobes as radiotracers for 201-thallium-based imaging.Prussian blue (PB) and its analogues on the nanometric scale are exciting nano-objects that combine the advantages of molecular-based materials and nanochemistry. Herein, we demonstrate that ultra-small PB nanoparticles of 2-3 nm can be easily labelled with radioactive 201Tl+ to obtain new nanoprobes as radiotracers for 201-thallium-based imaging. Electronic supplementary information (ESI) available: Experimental details and procedures, toxicological data, PXRD, TEM images, kinetics and adsorption isotherms, SPECT/CT images, Tl+ captation profiles. See DOI: 10.1039/c4nr03044c

  6. Gamma radiation measurements and Monte Carlo computations following myocardial perfusion imaging with 201Tl.

    PubMed

    Clouvas, A; Xanthos, S

    2012-12-01

    In the current study, the time-dependent retention of (201)Tl-thallous chloride (111 MBq) was measured in a 56-y-old man undergoing myocardial perfusion imaging. For 23 d following the (201)Tl injection, total-body retained activity was measured by (i) in situ gamma spectrometry using a portable high-purity germanium (HPGe) detector and (ii) ex vivo urine radioassay using a shielded HPGe detector. The time-dependent decrease in total-body activity followed a monoexponential function, exp(-0.011 t), with an excellent correlation (R(2)=0.9988) between the experimental data and the fitted values. The effective half-life, Teff, of (201)Tl (physical half-life, Tph: 72.9 h) was therefore 63 h and the biological half-life, Tb, 463 h=19.3 d, identical to those measured in the same patient in 1997 (i.e. 14 y ago). The time-dependent decrease in the urine activity concentration, which followed a monoexponential function, exp(-0.0115 t), corroborated the foregoing results. The correlation (R(2)=0.9939) between the experimental data and the fitted values was again excellent. The effective half-life, Teff, was 60.26 h and the biological half-life, Tb, 348 h=14.5 d. Monte Carlo simulation using a simple model of the patient as a unit-density cylinder filled with water and containing a uniform distribution of (201)Tl yielded photon flux results in reasonable agreement with the measured data. PMID:22611205

  7. NOTE: Comparison of correction techniques for simultaneous 201Tl/99mTc myocardial perfusion SPECT imaging: a dog study

    NASA Astrophysics Data System (ADS)

    Knesaurek, Karin; Machac, Josef

    2000-11-01

    We compared two correction methods for simultaneous 201Tl/99mTc dual-isotope single-photon emission computed tomography (SPECT). Both approaches use the information from the third energy window placed between the photopeak windows of the 201Tl and 99mTc. The first approach, described by Moore et al, corrects only for the contribution of the 99mTc to the 201Tl primary 70 keV window. We developed the three-window transformation dual-isotope correction method, which is a simultaneous cross-talk correction. The two correction methods were compared in a simultaneous 201Tl/99mTc sestamibi cardiac dog study. Three separate acquisitions were performed in this dog study: two single-isotope and one dual-isotope acquisition. The 201Tl single-isotope images were used as references. The total number of counts, and the contrast between the left ventricular cavity (LVC) and the myocardium, were used in 70 keV short-axis slices as parameters for evaluating the results of the dual-isotope correction methods. Three consecutive short-axis slices were used to calculate averaged contrast and the averaged total number of counts. The total number of the counts was 667 000 ± 500 and 414 500 ± 400 counts for the dual-isotope (201Tl + 99mTc) and single-isotope (201Tl-only) 70 keV images, respectively. The corrected dual-isotope images had 514 700 ± 700 and 368 000 ± 600 counts for Moore's correction and our approach, respectively. Moore's method improved contrast in the dual-isotope 70 keV image to 0.14 ± 0.03 from 0.11 ± 0.02, which was the value in the 70 keV non-corrected dual-isotope image. Our method improved the same contrast to 0.22 ± 0.03. The contrast in the 201Tl single-isotope 70 keV image was 0.28 ± 0.02. Both methods improved the 70 keV dual-isotope images. However, our approach provided slightly better images than Moore's correction when compared with 201Tl-only 70 keV images.

  8. Activity determination of a 201Tl solution by 4πβ-γ and sum-peak coincidence methods

    NASA Astrophysics Data System (ADS)

    Ruzzarin, A.; da Silva, M. A. L.; Iwahara, A.; da Silva, R. L.; Filho, O. L. T.; Poledna, R.; Lopes, R. T.

    2016-07-01

    201Tl is used in nuclear medicine in cardiac imaging for evaluating the injury level in cardiac muscle at rest and exercise. In this work the activity concentration of a 201 Tl radioactive solution has been absolutely determined using the 4πβ-γ coincidence and sum-peak coincidence methods. The presence of 202Tl radioactive impurity that imposes some difficult in the activity measurements was taken into account in the measurements. In the sum-peak method a planar germanium detector was used. The half-lives were evaluated by the reference source method and the results obtained were (3.033 ± 0.004) d and (12.320 ± 0.163) d, respectively, for 201Tl and 202Tl.

  9. A noninvasive method for evaluating portal circulation by administration of /sup 201/Tl per rectum

    SciTech Connect

    Tonami, N.; Nakajima, K.; Hisada, K.; Tanaka, N.; Kobayashi, K.

    1982-11-01

    A new method for evaluating portal systemic circulation by administration of /sup 201/Tl per rectum was performed in 13 control subjects and in 65 patients with various liver diseases. In normal controls, the liver was visualized on the 0--5-min image whereas the images of other organs such as the heart, spleen, and lungs were very poor. In patients with liver cirrhosis associated with portal-systemic shunt, and in many other patients with hepatocellular damage, the liver was not so clearly visualized, whereas radioactivity in other organs, especially the heart, became evident. The heart-to-liver uptake ratio at 20 min after administration (H/L ratio) was significantly higher in liver cirrhosis than in normals and patients with chronic hepatitis (p less than 0.001). The patients with esophageal varices showed a significantly higher H/L ratio compared with that in cirrhotic patients without esophageal varices (p less than 0.001). The H/L ratio also showed a significant difference (p less than 0.01) between Stage 1 and Stage 3 esophageal varices. Since there were many other patients with hepatocellular damage who had high H/L ratios similar to those in liver cirrhosis, the effect that hepatocellular damage has on the liver uptake of /sup 201/Tl is also considered. Our present data suggest that this noninvasive method seems to be useful in evaluating portal-to-systemic shunting.

  10. Myocardial imaging in dogs treated with grisorixin: relationship between /sup 201/Tl uptake and coronary blood flow

    SciTech Connect

    Moins, N.; Gachon, P.; Maublant, J.

    1982-04-01

    /sup 201/Tl myocardial imaging was performed in dogs after pretreatment with grisorixin, which appeared to increase the myocardial uptake of /sup 201/Tl. This effect of grisorixin was found to be dose dependent, with an optimal dose of 60 microgram/kg. The myocardial-to-background ratio, which was 1.92 in the control dogs, rose to 4.45. The increase in the absolute myocardial uptake was demonstrated in guinea pigs that received /sup 201/Tl after similar pretreatment with grisorixin. In the animals treated with 500 microgram/kg, the uptake of /sup 201/Tl by the heart was 35% over the control value. With 60 microgram/kg grisorixin, the coronary blood flow increased from 40 to 176 ml/min 5 min after the injection. This dose, optimal for imaging, induced the maximum vasodilator effect with only a very slight concomitant increase in the left-ventricular pressure and myocardial contractility. Above 60 microgram/kg, grisorixin appeared to be a potent inotropic agent, whereas below this dose it showed only coronary vasodilator properties. Some evidence for an ionophore effect of this compound was found in dogs pretreated with 60 microgram/kg. In these the radionuclide was injected when the coronary vasodilatation had become insignificant, but a significant improvement of the M/B ratio was still evident.

  11. Experimental regional myocardial ischaemia and myocardial uptake of potassium analogues; intercomparison of 42K, 86Rb and 201Tl.

    PubMed

    Kasalický, J; Mrhová, O; Stýs, V

    1983-01-01

    The uptake of 42K, 86Rb and 201Tl by non-ischaemic and ischaemic myocardium was determined in rats with coronary artery ligature lasting 10, 30, 60 and 120 min, and in control rats without ischaemia. Whereas the myocardial concentration of 201Tl and 42K in control rats was similar and higher than that of 86Rb, 201Tl was superior to the other two radionuclides due to its significantly higher accumulation in non-ischaemic myocardium and the higher ratio of non-ischaemic to ischaemic radioactivity. The 86Rb accumulation in non-ischaemic myocardium and non-ischaemic/ischaemic ratio began to decrease from its maximum at 10 min. 201Tl, 42K and 86Rb blood levels in intact animals decreased rapidly after intravenous injection to low and nearly stabilized values at 5 min. Na+K+-ATPase activity in the ischaemic myocardium was high in the acutely ischaemic myocardium and decreased to below control levels after 4 h of ischaemia; changes in activity could not influence the low uptake of potassium analogues in fresh ischaemic myocardium.

  12. Comparison of myocardial /sup 201/Tl clearance after maximal and submaximal exercise: implications for diagnosis of coronary disease: concise communication

    SciTech Connect

    Massie, B.M.; Wisneski, J.; Kramer, B.; Hollenberg, M.; Gertz, E.; Stern, D.

    1982-05-01

    Recently the quantitation of regional /sup 201/Tl clearance has been shown to increase the sensitivity of the scintigraphic detection of coronary disease. Although /sup 201/Tl clearance rates might be expected to vary with the degree of exercise, this relationship has not been explored. We therefore evaluated the rate of decrease in myocardial /sup 201/Tl activity following maximal and submaximal stress in seven normal subjects and 21 patients with chest pain, using the seven-pinhole tomographic reconstruction technique. In normals, the mean /sup 201/Tl clearance rate declined from 41% +/- 7 over a 3-hr period with maximal exercise to 25% +/- 5 after 3 hr at a submaximal level (p less than 0.001). Similar differences in clearance rates were found in the normally perfused regions of the left ventricle in patients with chest pain, depending on whether or not a maximal end point (defined as either the appearance of ischemia or reaching 85% of age-predicted heart rate) was achieved. In five patients who did not reach these end points, 3-hr clearance rates in uninvolved regions averaged 25% +/- 2, in contrast to a mean of 38% +/- 5 for such regions in 15 patients who exercised to ischemia or an adequate heart rate. These findings indicate that clearance criteria derived from normals can be applied to patients who are stressed maximally, even if the duration of exercise is limited, but that caution must be used in interpreting clearance rates in those who do not exercise to an accepted end point.

  13. [Effect of wall thickness of left ventricle on 201Tl myocardial SPECT images: myocardial phantom study].

    PubMed

    Koto, M; Namura, H; Kawase, O; Yamasaki, K; Kono, M

    1996-07-01

    201Tl myocardial SPECT is known for better sensitivity, specificity, and accuracy than planar images in detecting coronary artery disease and diagnosing myocardial viability. SPECT images are also superior to planar images in diagnostic sensitivity and anatomical orientation. However, as limitation of the spatial resolution of the machine, we often encounter poor SPECT plower image quality in patients with decreased wall thickness. To test the accuracy of SPECT images in patients with marked thinning of the left ventricular wall, as occurs in dilated cardiomyopathy, we performed a experimental study using myocardial phantom with 7 mm wall thickness. Tomographic image of the phantom images were rather heterogeneous, though no artificial defect was located. Dilated cardiomyopathy is thought to be characterized by patchy defects in the left ventricle. Careful attention should be given to elucidating myocardial perfusion in patients with a thin left ventricle wall, as there are technical limitations in addition to clinical features.

  14. Contamination and radiation exposure from sup 201 Tl in patients undergoing dialysis after a nuclear medicine study

    SciTech Connect

    Serrano, M.; Olson, A.; Man, C.; Galonsky, R.; Stein, R. )

    1991-03-01

    Our institution is a major kidney research and transplant center. Hemodialysis patients that are scheduled for renal transplant are given a 201Tl stress test. Possible radiation exposure and contamination are of concern to attending personnel. We investigated this situation and found measurable activity in the effluent of patients receiving dialysis but no significant contamination of equipment. We determined that dialysis personnel received minimal radiation exposure.

  15. Evaluation of simultaneous 201Tl/99mTc dual-isotope cardiac SPECT imaging with model-based crosstalk compensation using canine studies

    PubMed Central

    Du, Y.; Links, J. M.; Becker, L.; DiPaula, A. F.; Frank, T.; Schuleri, K. H.; Lardo, A. C.; Frey, E. C.

    2014-01-01

    Background Simultaneous 201Tl/99mTc-Sestamibi dual-isotope myocardial perfusion SPECT imaging can reduce imaging time and produce perfectly registered rest/stress images. However, crosstalk from 99mTc into 201Tl images can significantly reduce 201Tl image quality. We have developed a model-based compensation (MBC) method to compensate for this crosstalk. The method has previously been validated with phantom and simulation studies. In this study, we evaluated the MBC method using a canine model. Methods Left anterior descending or left circumflex coronary artery stenoses were created in 50 adult mongrel dogs weighing 20–30 kg. The dogs were injected with 111 MBq (3 mCi) of 201Tl at rest, and a SPECT study acquired. Stress was induced by administering adenosine to the dog, followed by injection of 740 MBq (20 mCi) of 99mTc-Sestamibi at peak stress. A second SPECT study was performed with data acquired in both 201Tl and 99mTc energy windows to provide simultaneous dual-isotope projection data. The images were reconstructed using the ordered subsets-expectation maximization (OS-EM) reconstruction algorithm with compensation for attenuation, scatter and detector response. For simultaneously acquired 201Tl data, we also applied the MBC method to compensate for crosstalk contamination from 99mTc. Results Without compensation, 99mTc crosstalk increased the estimated 201Tl activity concentration in the rest images and reduced defect contrast. After MBC, the 201Tl images were in good agreement with the registered single isotope images and ex vivo count data. The ischemic (IS) to non-ischemic (NIS) region 201Tl activity concentration ratios were computed for single isotope and dual isotope studies. The correlation with ex vivo IS-NIS ratios was 0.815 after MBC, compared to the 0.495 from data without compensation. In addition, the regression line for the IS-NIS ratios with MBC was almost parallel to the line of identity with a slope of 0.93, compared to a slope of 0

  16. Detection of coronary artery stenosis in children with Kawasaki disease. Usefulness of pharmacologic stress sup 201 Tl myocardial tomography

    SciTech Connect

    Kondo, C.; Hiroe, M.; Nakanishi, T.; Takao, A. )

    1989-09-01

    This study determined the feasibility and accuracy of quantitative 201Tl myocardial single-photon emission computed tomography (SPECT) after dipyridamole infusion to detect coronary obstructive lesions in children with Kawasaki disease. 201Tl distribution after dipyridamole infusion was measured in 23 normal children, and with these normal values, quantitative analysis of SPECT was performed in 49 patients. Thirty-four patients had coronary stenosis 90% or greater on angiograms. Side effects resulting from systemic vasodilation were observed in about 70%. Angina pectoris and ischemic ST changes were observed only in patients with coronary stenosis. These symptoms disappeared after aminophylline infusion. Results of visual and quantitative analysis of SPECT were compared. SPECT data were shown on two-dimensional polar maps, and the extent and severity scores were calculated. The sensitivity of SPECT for detection of overall coronary stenosis was 91% (visual analysis) and 88% (quantitative analysis). The specificity of SPECT was 60% visually and 93% quantitatively. The sensitivity of quantitative analysis to detect individual coronary stenosis was similar to that of visual analysis. However, the specificity of visual analysis to detect individual coronary artery stenosis was significantly less than that of quantitative analysis. From these data, we conclude that quantitative analysis of myocardial SPECT after dipyridamole infusion is a safe and accurate diagnostic method for identifying coronary stenosis in children with Kawasaki disease.

  17. Double-nuclide study of the myocardium using 201Tl and 123I-labeled fatty acids in non-ischemic myocardial diseases.

    PubMed

    Knapp, W H; Vyska, K; Machulla, H J; Notohamiprodjo, G; Schmidt, U; Knust, E J; Gleichmann, U

    1988-06-01

    Metabolic impairment and perfusion abnormalities are known to occur in hypertensive heart disease (HHD) and in cardiomyopathies. Free fatty acid (FFA) extraction is severely inhibited in a number of pathobiochemical reactions. This parameter was assessed using the radiolabeled FFA analogue 123I-(p-iodo-phenyl-)-pentadecanoic acid (IPPA) and 201Tl as perfusion marker, both of them injected at maximal physical workload. The regional extraction fraction of IPPA (IPPA-EF) was estimated by relating the regional IPPA and 201Tl uptake to each other. In HHD (normal coronary arteries) with posterior wall thickness less than or equal to 12 mm IPPA-EF was 77 +/- 18% (SD) in septum and 92 +/- 17% in the posterolateral wall (N = 13), with thickness of greater than 12 mm 60 +/- 23% in septum and 61 +/- 20% in the posterolateral wall (N = 8) when compared with IPPA-EF in normal subjects (= 100%, N = 9). In hypertrophic cardiomyopathy (HCM) IPPA-EF averaged 51 +/- 20% in septum and 87 +/- 10% in the posterolateral wall (N = 11). In these patient groups no systematic regional changes in 201TI uptake were observed. In dilated cardiomyopathy (DCM) both IPPA-EF and 201Tl uptake showed distinct regional variations and a great interindividual variability with a mean IPPA-EF reduction of 12% (N = 9). Thus, IPPA uptake in primarily non-ischemic myocardial disease may already be compromised when 201Tl uptake is unchanged. The double-nuclide method for IPPA-EF determination allows to eliminate the influence of flow in FFA imaging and enhances the potential of scintigraphy in the differential diagnosis of HHD versus coronary artery disease. PMID:3405780

  18. Estimation of infarct size by myocardial emission computed tomography with /sup 201/Tl and its relation to creatine kinase-MB release after myocardial infarction in man

    SciTech Connect

    Tamaki, S.; Nakajima, H.; Murakami, T.

    1982-11-01

    We evaluated emission computed tomography (ECT) /sup 201/Tl myocardial imaging in estimating infarct size (IS). In 18 patients in whom IS was estimated enzymatically at the time of the acute episode, planar /sup 201/Tl perfusion scintigraphy and ECT with a rotating gamma camera were performed 4 weeks after the first myocardial infarction. From the size of /sup 201/Tl perfusion defects, the infarct area in planar images and the infarct volume in reconstructed ECT images were measured by computerized planimetry. When scintigraphic IS was compared with the accumulated creatine kinase-MB isoenzyme release (CK-MBr), infarct volume determined from ECT correlated closely with CK-MBr (r . 0.89), whereas infarct area measured from planar images correlated less satisfactorily with the enzymatic IS (for an average infarct area from three views, r . 0.69; for the largest infarct area, r . 0.73). Although conventional scintigraphic evaluation is useful for detecting and localizing infarction, quantification of ischemic injury with this two-dimensional technique has a significant inherent limitation. The ECT approach can provide a more accurate three-dimensional quantitative estimate of infarction, and can corroborate the enzymatic estimate of IS.

  19. [Development and clinical application of an expert system for supporting diagnosis of 201Tl stress myocardial SPECT].

    PubMed

    Horino, M; Hosoba, M; Wani, H; Oriuchi, N; Tateno, M; Inoue, T; Sasaki, Y; Igarashi, H; Iizuka, T

    1990-02-01

    A consultation expert system which supports our computer aided reporting system was developed. The system was used for the evaluation of the two dimensional polar (bull's eye) display of 201Tl myocardial SPECT. The system consists of patients management (PM) and consultation expert systems (ES). The former is connected to image processors coupled with scinticameras. The bull's eye display of myocardial SPECT is transferred from image processor to the data base of PM. When inference request is made, the feature extraction program extracts information on localization, extent and severity of focal defects comparing count-rates pixel by pixel with the reference obtained from seven normal controls. The inference engine is activated to determine presence of focal defects utilizing diagnostic rules in the knowledge base. The results are sent back to PM and reported with the probability of assurance. Fifty eight patients with old myocardial infarction (OMI), angina pectoris (AP) and other diseases as well as normal controls were included in the study. The decision for presence or absence of focal defects by ES agreed with that by nuclear physicians (NP) in 301 segments among 330 (91%) in stress images. The presence of redistribution in delayed images agreed in 43 segments among 67 (64%). Image interpretation by ES agreed well with that of NP in patients with OMI (19/20) and AP (9/11). Seven were interpreted as normal by both ES and NP. The system is useful, as it provides NP with complementary and supportive information applicable to decision making and reporting. Further clinical experiences can improve knowledge base for better ES function.

  20. Using adaptive neuro-fuzzy inference system technique for crosstalk correction in simultaneous 99mTc/201Tl SPECT imaging: A Monte Carlo simulation study

    NASA Astrophysics Data System (ADS)

    Heidary, Saeed; Setayeshi, Saeed

    2015-01-01

    This work presents a simulation based study by Monte Carlo which uses two adaptive neuro-fuzzy inference systems (ANFIS) for cross talk compensation of simultaneous 99mTc/201Tl dual-radioisotope SPECT imaging. We have compared two neuro-fuzzy systems based on fuzzy c-means (FCM) and subtractive (SUB) clustering. Our approach incorporates eight energy-windows image acquisition from 28 keV to 156 keV and two main photo peaks of 201Tl (77±10% keV) and 99mTc (140±10% keV). The Geant4 application in emission tomography (GATE) is used as a Monte Carlo simulator for three cylindrical and a NURBS Based Cardiac Torso (NCAT) phantom study. Three separate acquisitions including two single-isotopes and one dual isotope were performed in this study. Cross talk and scatter corrected projections are reconstructed by an iterative ordered subsets expectation maximization (OSEM) algorithm which models the non-uniform attenuation in the projection/back-projection. ANFIS-FCM/SUB structures are tuned to create three to sixteen fuzzy rules for modeling the photon cross-talk of the two radioisotopes. Applying seven to nine fuzzy rules leads to a total improvement of the contrast and the bias comparatively. It is found that there is an out performance for the ANFIS-FCM due to its acceleration and accurate results.

  1. Quantification of infarct size by /sup 201/Tl single-photon emission computed tomography during acute myocardial infarction in humans. Comparison with enzymatic estimates

    SciTech Connect

    Mahmarian, J.J.; Pratt, C.M.; Borges-Neto, S.; Cashion, W.R.; Roberts, R.; Verani, M.S.

    1988-10-01

    We prospectively investigated whether /sup 201/Tl single-photon emission computed tomography (SPECT) could accurately diagnose the presence and quantify the extent of acute myocardial infarction when compared with infarct size assessed by plasma MB-creatine kinase activity. Thirty patients with enzymatic evidence of infarction were imaged within 12-36 hours of chest pain (mean, 23.4 hours). No patient had a previous infarction, and none underwent intervention seeking to restore coronary patency. Infarct size was quantified with computer-generated polar maps of the myocardial radioactivity and expressed as a percentage of the total left ventricular volume. To assess left and right ventricular performance, blood-pool gated radionuclide angiography was performed immediately after SPECT. All 30 patients had perfusion defects consistent with myocardial infarction. Scintigraphic and enzymatic estimates of infarct size correlated well for the group as a whole (r = 0.78, p less than 0.001, SEE = 9.1) but especially for those patients with anterior infarction (r = 0.91, p less than 0.001, SEE = 7.9). The poor correlation observed in patients with inferior infarction (r = 0.50, p less than 0.05, SEE = 10.0) was believed to be related to the frequent occurrence of right ventricular involvement because SPECT assessed only left ventricular damage, whereas the enzymatic method estimated the myocardial injury in both ventricles. A quantitative index of right ventricular infarct size, derived from the relation between the scintigraphic and enzymatic estimates, had a strong inverse correlation with right ventricular ejection fraction (r = -0.89, p less than 0.001, SEE = 3.6).

  2. Prediction of functional recovery and prognosis in patients with acute myocardial infarction by 123I-BMIPP and 201Tl myocardial single photon emission computed tomography: a multicenter trial.

    PubMed

    Nishimura, T; Nishimura, S; Kajiya, T; Sugihara, H; Kitahara, K; Imai, K; Muramatsu, T; Takahashi, N; Yoshida, H; Osada, T; Terada, K; Ito, T; Naruse, H; Iwabuchi, M

    1998-10-01

    123I-BMIPP [15-(p-iodophenyl)-3-(R,S)-methylpentadecanoic acid] was developed for metabolic imaging with SPECT. A multicenter collaborative study was conducted on a large patient series to determine whether 123I-BMIPP and 201Tl myocardial SPECT are of use in predicting the prognosis and ventricular function after acute myocardial infarction (AMI). Patients with uncomplicated first AMI underwent resting 123I-BMIPP and 201Tl myocardial SPECT in the subacute phase after the onset of AMI. Of these, 167 patients who had been followed up for an average of 22 months were retrospectively reviewed to predict serious cardiac events and recurrent ischemia. In addition, the association between changes in radionuclide parameters and recurrent ischemia was investigated in Subgroup A (58 patients) who had repeated SPECT in the chronic phase. Furthermore, prediction of the ejection fraction (EF) was investigated in Subgroup B (94 patients) and Subgroup C (76 patients) in whom left ventriculography was performed at the time of discharge and 90 days or more after the onset, respectively. The prognosis was generally favorable, with 4 cases of cardiac death (2%), 3 of heart failure (2%), 4 of nonfatal reMI (2%), and 25 of recurrent ischemia (15%). The results of Cox multivariate regression analysis revealed a high probability of serious cardiac events in patients who were elderly (p = 0.04), who had 90% or more residual stenosis of the infarct-related artery (p = 0.09), and who had a high BMIPP defect score (p = 0.17). There was a high probability of recurrent ischemia in elderly patients (p = 0.10) who had multi-vessel disease (p = 0.03), but no association was found with radionuclide parameters in the subacute phase. In Subgroup A, however, the probability of recurrent ischemia tended to be high in patients with a large mismatch scorebetween 123I-BMIPP and 201Tl in the subacute to chronic phase. An important observation was that the extent of BMIPP defect was more strongly

  3. Comparison of an adaptive neuro-fuzzy inference system and an artificial neural network in the cross-talk correction of simultaneous 99 m Tc / 201Tl SPECT imaging using a GATE Monte-Carlo simulation

    NASA Astrophysics Data System (ADS)

    Heidary, Saeed; Setayeshi, Saeed; Ghannadi-Maragheh, Mohammad

    2014-09-01

    The aim of this study is to compare the adaptive neuro-fuzzy inference system (ANFIS) and the artificial neural network (ANN) to estimate the cross-talk contamination of 99 m Tc / 201 Tl image acquisition in the 201 Tl energy window (77 ± 15% keV). GATE (Geant4 Application in Emission and Tomography) is employed due to its ability to simulate multiple radioactive sources concurrently. Two kinds of phantoms, including two digital and one physical phantom, are used. In the real and the simulation studies, data acquisition is carried out using eight energy windows. The ANN and the ANFIS are prepared in MATLAB, and the GATE results are used as a training data set. Three indications are evaluated and compared. The ANFIS method yields better outcomes for two indications (Spearman's rank correlation coefficient and contrast) and the two phantom results in each category. The maximum image biasing, which is the third indication, is found to be 6% more than that for the ANN.

  4. [Comparison between 123I-BMIPP and 201TlCl myocardial imaging by circumferential profile analysis in patients with myocardial infarction--evaluation of effects of vascular reconstruction in patients with myocardial infarction].

    PubMed

    Ohsumi, Y; Watanabe, T; Nagano, T

    1994-10-01

    We quantitatively evaluated the effects of vascular reconstruction according to the stage by 123I-BMIPP and 201TlCl using circumferential profile (CP) curve method in patients with myocardial infarction. (1) Comparison of the CP curves for the two nuclides in normal volunteers (n = 9) showed no difference in distribution. (2) In patient with myocardial infarction (n = 32) the severity score was evaluated using the CP curves obtained in the normal volunteers. Type B (marked decrease in 123I-BMIPP accumulation) accounted for 83% in the group in whom vascular reconstruction was performed in the acute stage (Group I) and 91% in the group in whom vascular reconstruction was performed in the chronic stage (Group II). On the other hand, type E (similar accumulation between the two nuclides) accounted for 79% in the group in whom vascular reconstruction was unsuccessful or was not performed (Group III). The severity score for each nuclide did not significantly differ among Group I, II and III. The 123I-BMIPP/201TlCl ratio was the highest in Group II, followed in order by Group I and Group III (p < 0.05). The assessment of the ratio of "severity scores" for both nuclides is considered to be useful for evaluation of the surviving myocardium, rather than the assessment of a single nuclide. PMID:7807719

  5. DOS.

    ERIC Educational Resources Information Center

    Traven, Bill

    1988-01-01

    Discusses using the DOS PATH command (for MS-DOS) to enable the microcomputer user to move from directory to directory on a hard drive. Lists the commands to be programed, gives examples, and explains the use of each. (MVL)

  6. DOS basics

    SciTech Connect

    O`Connor, P.

    1994-09-01

    DOS is an acronym for Disk Operating System. It is actually a set of programs that allows you to control your personal computer. DOS offers the capabilities to create and manage files; organize and maintain information placed on disks; use application programs such as WordPerfect, Lotus 123, Excel, Windows, etc. In addition, DOS provides the basic utilities needed to copy files from one area to another, delete files and list files. The latest version of DOS also offers more advanced features that include hard disk compression and memory management. Basic DOS commands are discussed.

  7. Incidental Detection of Shoulder Peripheral T-Cell Lymphoma During the Redistribution Phase of 201Tl Myocardial Perfusion Scintigraphy.

    PubMed

    Chen, Yu-Ren; Hsieh, Te-Chun; Yen, Kuo-Yang; Kao, Chia-Hung

    2015-10-01

    A 74-year-old woman underwent Tl myocardial perfusion scan for cardiac symptoms; increased radiotracer accumulation in the left shoulder was found in the redistribution images only, and the shoulder was normal in the stress images. Suspecting septic arthritis subsequent investigations were performed, and peripheral T-cell lymphoma was diagnosed. Attention should also be paid to extracardiac sites in interpreting redistribution images taken as late as 4 hours apart from stress images because some clinically pertinent ancillary findings may be found in redistribution images only. PMID:26018700

  8. A DOS Primer for Librarians.

    ERIC Educational Resources Information Center

    Beecher, Henry

    1989-01-01

    Presents a basic orientation to the functions and capabilities of disk operating systems (DOS), aimed at the nontechnically oriented user of IBM personal computers and compatible microcomputers. Areas discussed include booting up, the use of floppy and hard disks, file storage and manipulation, and directories. Further readings are provided. (CLB)

  9. Comparison of thallium 201 (TL) SPECT and F-18 fluoro-deoxyglucose (FDG) PET in the evaluation of MRI lesions in patients with gliomas after therapy

    SciTech Connect

    Wong, F.C.L.; Garcia, J.R.; Yung, W.K.A.

    1994-05-01

    Although both Tl-201 SPECT and F-18 FDG PET are helpful for the detection of recurrent gliomas, there is DO comparative study of these techniques for the same patient group. This study is performed to compare the efficacy of TL SPECT and FDG PET in differentiating recurrent glioma from post-treatment necrosis. Twenty patients (16M/4 F) treated for gliomas (surgery, radiation and/or chemotherapy) with 24 instructive MRI enhancing lesions underwent TL-201 SPECT and F-18 FDG PET within 1 week. The lesions were graded 0 to 4 (by consensus of three nuclear radiologists) with increasing confidence for recurrent tumors. Semiquantitative evaluations include lesion/scalp TL-201 ratios (L/S TL) and lesion/cortex F-18 FDG (L/C FDG) standard uptake value ratios. With clinical follow-up (12/24) and histopathologic confirmation (12/24), sensitivity and specificity for each grade were used to construct the receiver-operator-characteristic (ROC) curve for comparison. Recurrent gliomas were confirmed in 12/24 lesions (9/12 by pathology; 3/12 by follow-up). Post-treatment necrosis was confirmed in 12/24 lesions (9/12 by follow-up; 3/12 by pathology). The L/S TL ratios were [1.99{plus_minus}0.77] for gliomas and [1.14{plus_minus}0.22] for necrosis; the L/C FDG ratios were 0.86{plus_minus}0.43 for gliomas and 0.43{plus_minus}0.15 for necrosis. Although none of the semiquantitative measurements from TL SPECT and FDG PET could completely distinguish gliomas from post-treatment necrosis, FDG PET was superior to TL SPECT on the ROC curves. While TL-201 SPECT and F-18 FDG PET provide different and probably complementary metabolic measurements of brain lesions, this preliminary work suggests FDG PET is a better tool to evaluate enhancing MRI lesions in patients with treated gliomas. Further confirmation will require studies of more patients.

  10. Iterative deconvolution of simultaneous 99mTc and 201Tl projection data measured on a CdZnTe-based cardiac SPECT scanner

    NASA Astrophysics Data System (ADS)

    Kacperski, Krzysztof; Erlandsson, Kjell; Ben-Haim, Simona; Hutton, Brian F.

    2011-03-01

    We present a method of correcting self-scatter and crosstalk effects in simultaneous technetium-99m/thallium-201 stress/rest myocardial perfusion (single photon emission computed tomography) SPECT scans. The method, which is in essence a hybrid between the triple energy window method and scatter modelling, is based on a model of spatial and spectral distribution of projection counts in several selected energy windows. The parameters of the model are determined from measurements of thin rod sources in air when no in-object scatter or attenuation effects are present. The model equations are solved using the iterative maximum likelihood expectation maximization algorithm in the projection space to find estimates of the primary photopeak counts of both radionuclides. The method has been developed particularly for a novel dedicated cardiac camera based on CdZnTe pixellated detectors, although it can also be adapted to a conventional scintillator camera. The method has been validated in anthropomorphic phantom experiments. Significant improvement in defect contrast has been observed with only moderate increase in image noise. The application of the method to patient data is illustrated.

  11. Iterative deconvolution of simultaneous 99mTc and 201Tl projection data measured on a CdZnTe-based cardiac SPECT scanner.

    PubMed

    Kacperski, Krzysztof; Erlandsson, Kjell; Ben-Haim, Simona; Hutton, Brian F

    2011-03-01

    We present a method of correcting self-scatter and crosstalk effects in simultaneous technetium-99m/thallium-201 stress/rest myocardial perfusion (single photon emission computed tomography) SPECT scans. The method, which is in essence a hybrid between the triple energy window method and scatter modelling, is based on a model of spatial and spectral distribution of projection counts in several selected energy windows. The parameters of the model are determined from measurements of thin rod sources in air when no in-object scatter or attenuation effects are present. The model equations are solved using the iterative maximum likelihood expectation maximization algorithm in the projection space to find estimates of the primary photopeak counts of both radionuclides. The method has been developed particularly for a novel dedicated cardiac camera based on CdZnTe pixellated detectors, although it can also be adapted to a conventional scintillator camera. The method has been validated in anthropomorphic phantom experiments. Significant improvement in defect contrast has been observed with only moderate increase in image noise. The application of the method to patient data is illustrated.

  12. Iterative deconvolution of simultaneous 99mTc and 201Tl projection data measured on a CdZnTe based cardiac SPECT scanner

    PubMed Central

    Kacperski, Krzysztof; Erlandsson, Kjell; Ben-Haim, Simona; Hutton, Brian F.

    2011-01-01

    We present a method of correcting self-scatter and crosstalk effects in simultaneous technetium-99m/thallium-201 stress/rest myocardial perfusion SPECT scans. The method, which is in essence a hybrid between the TEW method and scatter modelling, is based on a model of spatial and spectral distribution of projection counts in several selected energy windows. The parameters of the model are determined from measurements of thin rod sources in air when no in-object scatter or attenuation effects are present. The model equations are solved using the iterative Maximum Likelihood Expectation Maximisation (ML-EM) algorithm in the projection space to find estimates of the primary photopeak counts of both radionuclides. The method has been developed particularly for a novel dedicated cardiac camera based on CdZnTe pixellated detectors, although it can also be adapted to a conventional scintillator camera. The method has been validated in anthropomorphic phantom experiments. Significant improvement in defect contrast has been observed with only moderate increase in image noise. The application of the method to patient data is ilustrated. PMID:21317483

  13. A DOS Primer for Librarians: Part II.

    ERIC Educational Resources Information Center

    Beecher, Henry

    1990-01-01

    Provides an introduction to DOS commands and strategies for the effective organization and use of hard disks. Functions discussed include the creation of directories and subdirectories, enhanced copying, the assignment of disk drives, and backing up the hard disk. (CLB)

  14. DOS Batch Files As Control Programs

    NASA Technical Reports Server (NTRS)

    Van Dyk, David A.

    1991-01-01

    Computer-programming technique circumvents maximum of 640K imposed on random-access memory (RAM) by DOS (Disk Operating System) software. Involves breaking application program into smaller programs. Each resulting subprogram, when compiled and linked, must be small enough to fit within 640K of RAM. Retrieved from storage on disk as needed. In terms of DOS software, each subprogram ".EXE" file executed in "stand-alone" manner.

  15. 27 CFR 9.175 - Dos Rios.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... TREASURY LIQUORS AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.175 Dos Rios. (a... is located in northern Mendocino County, California, at the confluence of the Eel River and the Middle Fork of the Eel River. The area's boundaries are defined as follows— (1) Beginning in...

  16. "DOS for Managers." Management Training Series.

    ERIC Educational Resources Information Center

    Marion County Schools, Fairmont, WV.

    A plan is provided for a lesson on disk operating systems (DOS) for managers. Twenty-five lesson objectives are listed, followed by suggestions for learning activities and special resources. In the presentation section, key points and content are provided for 25 instructional topics that correspond to the 25 lesson objectives. The topics are as…

  17. DOS: the discrete-ordinates system. [LMFBR

    SciTech Connect

    Rhoades, W. A.; Emmett, M. B.

    1982-09-01

    The Discrete Ordinates System determines the flux of neutrons or photons due either to fixed sources specified by the user or to sources generated by particle interaction with the problem materials. It also determines numerous secondary results which depend upon flux. Criticality searches can be performed. Numerous input, output, and file manipulation facilities are provided. The DOS driver program reads the problem specification from an input file and calls various program modules into execution as specified by the input file.

  18. DIGLIB. PC-DOS Graphics Subroutine Library

    SciTech Connect

    Brand, H.R.

    1989-02-01

    DIGLIB is a collection of general graphics subroutines. It was designed to be small, reasonably fast, device-independent, and compatible with DEC-supplied operating systems for VAXes, PDP-11s, and LSI-11s, and the DOS operating system for IBM PCs and IBM-compatible machines. DIGLIB/VMS runs on the VAX and MicroVAX series of computers under VMS. The software is readily usable by casual programmers for two-dimensional plotting.

  19. From DOS to UNIX: An independent's experience

    SciTech Connect

    Hepguler, G.; Meehan, D.N.

    1993-06-01

    Union Pacific Resources Co. (UPRC) is a large independent operator with about 100 petroleum engineers. UPRC has a reasonably sophisticated PC network with many hundreds of PC's connected by several local area network (LAN) servers. Essentially all engineers have a 386-based PC on their desks with access to a host of software packages, peripheral devices, and mainframe computers, Many engineers have acquired 486-based PC's. UPRC's solution has involved migrating from a DOS-based platform on individual users' desks to UNIX workstations. Dozens of UNIX workstations are networked; some are on the desk', while others are located in central locations. Reservoir simulation, geostatistical modeling, image processing, and log analysis are now done exclusively on the UNIX workstations. Numerous DOS-based programs, however, have not yet been migrated into the UNIX environment. This paper describes the topography of both PC DOS and UNIX workstations networks in UPRC and examines the flow of information in each network configuration to identify differences. The successes and failures of various techniques for providing access to both platforms are presented.

  20. Fast interrupt platform for extended DOS

    NASA Technical Reports Server (NTRS)

    Duryea, T. W.

    1995-01-01

    Extended DOS offers the unique combination of a simple operating system which allows direct access to the interrupt tables, 32 bit protected mode access to 4096 MByte address space, and the use of industry standard C compilers. The drawback is that fast interrupt handling requires both 32 bit and 16 bit versions of each real-time process interrupt handler to avoid mode switches on the interrupts. A set of tools has been developed which automates the process of transforming the output of a standard 32 bit C compiler to 16 bit interrupt code which directly handles the real mode interrupts. The entire process compiles one set of source code via a make file, which boosts productivity by making the management of the compile-link cycle very simple. The software components are in the form of classes written mostly in C. A foreground process written as a conventional application which can use the standard C libraries can communicate with the background real-time classes via a message passing mechanism. The platform thus enables the integration of high performance real-time processing into a conventional application framework.

  1. Teaching Bibliometric Analysis and MS/DOS Commands.

    ERIC Educational Resources Information Center

    Dou, Henri; And Others

    1988-01-01

    Outlines the steps involved in bibliometric studies, and demonstrates the ability to execute simple studies on microcomputers by downloading files using only the capability of MS/DOS. Detailed illustrations of the MS/DOS commands used are provided. (eight references) (CLB)

  2. The Heme-Based Oxygen-Sensor Phosphodiesterase Ec DOS (DosP): Structure-Function Relationships

    PubMed Central

    Shimizu, Toru

    2013-01-01

    Escherichia coli Direct Oxygen Sensor (Ec DOS, also known as Ec DosP) is a heme-based O2-sensing phosphodiesterase from Escherichia coli that catalyzes the conversion of cyclic-di-GMP to linear di-GMP. Cyclic-di-GMP is an important second messenger in bacteria, highlighting the importance of understanding structure-function relationships of Ec DOS. Ec DOS is composed of an N-terminal heme-bound O2-sensing PAS domain and a C-terminal phosphodiesterase catalytic domain. Notably, its activity is markedly enhanced by O2 binding to the heme Fe(II) complex in the PAS sensor domain. X-ray crystal structures and spectroscopic and catalytic characterization of the wild-type and mutant proteins have provided important structural and functional clues to understanding the molecular mechanism of intramolecular catalytic regulation by O2 binding. This review summarizes the intriguing findings that have obtained for Ec DOS. PMID:25586128

  3. Izabel dos Santos and the training of the health workers.

    PubMed

    Paiva, Carlos Henrique Assunção

    2015-06-01

    This article discusses the career of Izabel dos Santos (1927-2010) as a means of examining the connections between health schools and agendas in contemporary Brazil. The article highlights dos Santos's training and her work in the Serviço Especial de Saúde Pública (SESP- Special Public Health Service), the Pan American Health Organization (PAHO) and in the formulation and implementation of national training programs for human resources within the area of health from the late 1970s onwards. The article highlights dos Santos's central role in the formulation and implementation of training policies for health workers, especially nursing technicians and assistants, and demonstrates how she occupies an important place in the history of Brazilian public health.

  4. Dos dosis de vacuna contra los VPH pueden proteger

    Cancer.gov

    Dos dosis de Cervarix, la vacuna contra virus del papiloma humano (VPH), fueron tan efectivas como la pauta normal actual de tres dosis después de cuatro años de seguimiento. El estudio de vacuna en Costa Rica, patrocinado por el NCI, fue diseñado para ev

  5. Special Section--Library Workstations: Mac and DOS.

    ERIC Educational Resources Information Center

    Valauskas, Ed; Flower, Eric

    1993-01-01

    Two articles discuss the library hardware marketplace. The first examines the Apple Macintosh in libraries from 1984 to the present, including linking libraries, computers, and endusers over large geographic distances. The second article discusses upgrading components of systems in the IBM compatible, MS-DOS, and Windows environments as costs…

  6. MS DOS Tool Software Including Public Domain, Grades K-6.

    ERIC Educational Resources Information Center

    New York City Board of Education, Brooklyn, NY. Div. of Computer Information Services.

    This curriculum guide is designed to assist teachers and supervisors in introducing lower elementary students to the MS DOS computer and the word processing program PC Write. Accompanying this guide are two program disks: PC Write, which is a public domain word processing program and Disk Care, which reinforces rules for caring for disks. The…

  7. Deceiving entropy-based DoS detection

    NASA Astrophysics Data System (ADS)

    Özçelik, Ä.°lker; Brooks, Richard R.

    2014-06-01

    Denial of Service (DoS) attacks disable network services for legitimate users. A McAfee report shows that eight out of ten Critical Infrastructure Providers (CIPs) surveyed had a significant Distributed DoS (DDoS) attack in 2010.1 Researchers proposed many approaches for detecting these attacks in the past decade. Anomaly based DoS detection is the most common. In this approach, the detector uses statistical features; such as the entropy of incoming packet header fields like source IP addresses or protocol type. It calculates the observed statistical feature and triggers an alarm if an extreme deviation occurs. However, intrusion detection systems (IDS) using entropy based detection can be fooled by spoofing. An attacker can sniff the network to collect header field data of network packets coming from distributed nodes on the Internet and fuses them to calculate the entropy of normal background traffic. Then s/he can spoof attack packets to keep the entropy value in the expected range during the attack. In this study, we present a proof of concept entropy spoofing attack that deceives entropy based detection approaches. Our preliminary results show that spoofing attacks cause significant detection performance degradation.

  8. Structures of Mycobacterium tuberculosis DosR and DosR-DNA Complex Involved in Gene Activation during Adaptation to Hypoxic Latency

    SciTech Connect

    Wisedchaisri, Goragot; Wu, Meiting; Rice, Adrian E; Roberts, David M; Sherman, David R; Hol, Wim G.J.

    2010-07-20

    On encountering low oxygen conditions, DosR activates the transcription of 47 genes, promoting long-term survival of Mycobacterium tuberculosis in a non-replicating state. Here, we report the crystal structures of the DosR C-terminal domain and its complex with a consensus DNA sequence of the hypoxia-induced gene promoter. The DosR C-terminal domain contains four {alpha}-helices and forms tetramers consisting of two dimers with non-intersecting dyads. In the DNA-bound structure, each DosR C-terminal domain in a dimer places its DNA-binding helix deep into the major groove, causing two bends in the DNA. DosR makes numerous protein-DNA base contacts using only three amino acid residues per subunit: Lys179, Lys182, and Asn183. The DosR tetramer is unique among response regulators with known structures.

  9. A natural product based DOS library of hybrid systems.

    PubMed

    Prabhu, Ganesh; Agarwal, Shalini; Sharma, Vijeta; Madurkar, Sanjay M; Munshi, Parthapratim; Singh, Shailja; Sen, Subhabrata

    2015-05-01

    Here we described a natural product inspired modular DOS strategy for the synthesis of a library of hybrid systems that are structurally and stereochemically disparate. The main scaffold is a pyrroloisoquinoline motif, that is synthesized from tandem Pictet-Spengler lactamization. The structural diversity is generated via "privileged scaffolds" that are attached at the appropriate site of the motif. Screening of the library compounds for their antiplasmodial activity against chloroquine sensitive 3D7 cells indicated few compounds with moderate activity (20-50 μM). A systematic comparison of structural intricacy between the library members and a natural product dataset obtained from ZINC(®) revealed comparable complexity. PMID:25794788

  10. Sedimentation survey of Lago Dos Bocas, Puerto Rico, June 1985

    USGS Publications Warehouse

    Quinones, Ferdinand; Melendez, Frank; Bonnet, Carlos

    1989-01-01

    A survey of the sedimentation of Dos Bocas reservoir, in central Puerto Rico, was conducted during July 1985. The survey showed that the capacity of the reservoir has declined from 30,420 acre-ft in 1942 to about 19,620 acre-ft. Sediment is accumulating in the reservoir at an average rate of about 251 acre-ft/yr, or about 0.83%/yr of the original capacity. The expected usable life of the reservoir on the basis of the long-term sedimentation rate is about 78 years. However, the sedimentation rate appears to have increased significantly since 1979. During the last six years, the average sedimentation rate has exceeded 600 acre-ft/yr. If this rate is maintained, the expected usable life of the reservoir would be about 32 years. (Author 's abstract)

  11. Document image archive transfer from DOS to UNIX

    NASA Technical Reports Server (NTRS)

    Hauser, Susan E.; Gill, Michael J.; Thoma, George R.

    1994-01-01

    An R&D division of the National Library of Medicine has developed a prototype system for automated document image delivery as an adjunct to the labor-intensive manual interlibrary loan service of the library. The document image archive is implemented by a PC controlled bank of optical disk drives which use 12 inch WORM platters containing bitmapped images of over 200,000 pages of medical journals. Following three years of routine operation which resulted in serving patrons with articles both by mail and fax, an effort is underway to relocate the storage environment from the DOS-based system to a UNIX-based jukebox whose magneto-optical erasable 5 1/4 inch platters hold the images. This paper describes the deficiencies of the current storage system, the design issues of modifying several modules in the system, the alternatives proposed and the tradeoffs involved.

  12. The Mycobacterium DosR regulon structure and diversity revealed by comparative genomic analysis.

    PubMed

    Chen, Tian; He, Liming; Deng, Wanyan; Xie, Jianping

    2013-01-01

    Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), which claims approximately two million people annually, remains a global health concern. The non-replicating or dormancy like state of this pathogen which is impervious to anti-tuberculosis drugs is widely recognized as the culprit for this scenario. The dormancy survival regulator (DosR) regulon, composed of 48 co-regulated genes, is held as essential for Mtb persistence. The DosR regulon is regulated by a two-component regulatory system consisting of two sensor kinases-DosS (Rv3132c) and DosT (Rv2027c), and a response regulator DosR (Rv3133c). The underlying regulatory mechanism of DosR regulon expression is very complex. Many factors are involved, particularly the oxygen tension. The DosR regulon enables the pathogen to persist during lengthy hypoxia. Comparative genomic analysis demonstrated that the DosR regulon is widely distributed among the mycobacterial genomes, ranging from the pathogenic strains to the environmental strains. In-depth studies on the DosR response should provide insights into its role in TB latency in vivo and shape new measures to combat this exceeding recalcitrant pathogen.

  13. Myocardial metabolic, hemodynamic, and electrocardiographic significance of reversible thallium-201 abnormalities in hypertrophic cardiomyopathy

    SciTech Connect

    Cannon, R.O. 3d.; Dilsizian, V.; O'Gara, P.T.; Udelson, J.E.; Schenke, W.H.; Quyyumi, A.; Fananapazir, L.; Bonow, R.O. )

    1991-05-01

    Exercise-induced abnormalities during thallium-201 scintigraphy that normalize at rest frequently occur in patients with hypertrophic cardiomyopathy. However, it is not known whether these abnormalities are indicative of myocardial ischemia. Fifty patients with hypertrophic cardiomyopathy underwent exercise {sup 201}Tl scintigraphy and, during the same week, measurement of myocardial lactate metabolism and hemodynamics during pacing stress. Thirty-seven patients (74%) had one or more {sup 201}Tl abnormalities that completely normalized after 3 hours of rest; 26 had regional myocardial {sup 201}Tl defects, and 26 had apparent left ventricular cavity dilatation with exercise, with 15 having coexistence of these abnormal findings. Of the 37 patients with reversible {sup 201}Tl abnormalities, 27 (73%) had metabolic evidence of myocardial ischemia during rapid atrial pacing compared with four of 13 patients (31%) with normal {sup 201}Tl scans (p less than 0.01). Eleven patients had apparent cavity dilatation as their only {sup 201}Tl abnormality; their mean postpacing left ventricular end-diastolic pressure was significantly higher than that of the 13 patients with normal {sup 201}Tl studies (33 +/- 5 versus 21 +/- 10 mm Hg, p less than 0.001). There was no correlation between the angiographic presence of systolic septal or epicardial coronary arterial compression and the presence or distribution of {sup 201}Tl abnormalities. Patients with ischemic ST segment responses to exercise had an 80% prevalence rate of reversible {sup 201}Tl abnormalities and a 70% prevalence rate of pacing-induced ischemia. However, 69% of patients with nonischemic ST segment responses had reversible {sup 201}Tl abnormalities, and 55% had pacing-induced ischemia. Reversible {sup 201}Tl abnormalities during exercise stress are markers of myocardial ischemia in hypertrophic cardiomyopathy and most likely identify relatively underperfused myocardium.

  14. 33 CFR 106.250 - Declaration of Security (DoS).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., ensure the Facility Security Officer (FSO) and Master, Vessel Security Officer (VSO), or their designated... FSO and Master, VSO, or their designated representatives, must sign the written DoS. (c) Neither...

  15. The DosR Regulon Modulates Adaptive Immunity and Is Essential for Mycobacterium tuberculosis Persistence

    PubMed Central

    Mehra, Smriti; Foreman, Taylor W.; Didier, Peter J.; Ahsan, Muhammad H.; Hudock, Teresa A.; Kissee, Ryan; Golden, Nadia A.; Gautam, Uma S.; Johnson, Ann-Marie; Alvarez, Xavier; Russell-Lodrigue, Kasi E.; Doyle, Lara A.; Roy, Chad J.; Niu, Tianhua; Blanchard, James L.; Khader, Shabaana A.; Lackner, Andrew A.; Sherman, David R.

    2015-01-01

    Rationale: Hypoxia promotes dormancy by causing physiologic changes to actively replicating Mycobacterium tuberculosis. DosR controls the response of M. tuberculosis to hypoxia. Objectives: To understand DosR's contribution in the persistence of M. tuberculosis, we compared the phenotype of various DosR regulon mutants and a complemented strain to M. tuberculosis in macaques, which faithfully model M. tuberculosis infection. Methods: We measured clinical and microbiologic correlates of infection with M. tuberculosis relative to mutant/complemented strains in the DosR regulon, studied lung pathology and hypoxia, and compared immune responses in lung using transcriptomics and flow cytometry. Measurements and Main Results: Despite being able to replicate initially, mutants in DosR regulon failed to persist or cause disease. On the contrary, M. tuberculosis and a complemented strain were able to establish infection and tuberculosis. The attenuation of pathogenesis in animals infected with the mutants coincided with the appearance of a Th1 response and organization of hypoxic lesions wherein M. tuberculosis expressed dosR. The lungs of animals infected with the mutants (but not the complemented strain) exhibited early transcriptional signatures of T-cell recruitment, activation, and proliferation associated with an increase of T cells expressing homing and proliferation markers. Conclusions: Delayed adaptive responses, a hallmark of M. tuberculosis infection, not only lead to persistence but also interfere with the development of effective antituberculosis vaccines. The DosR regulon therefore modulates both the magnitude and the timing of adaptive immune responses in response to hypoxia in vivo, resulting in persistent infection. Hence, DosR regulates key aspects of the M. tuberculosis life cycle and limits lung pathology. PMID:25730547

  16. Prevalence and clinical significance of painless ST segment depression during early postinfarction exercise testing

    SciTech Connect

    Gibson, R.S.; Beller, G.A.; Kaiser, D.L.

    1987-03-01

    In a recent study of 190 survivors of acute myocardial infarction, the authors sought to determine whether exercise-induced painless ST segments depression indicates residual myocardial ischemia, as defined by /sup 201/Tl scintigraphic criteria. 2 weeks after uncomplicated myocardial infarction, and whether quantitative /sup 201/Tl imaging enhances the prognostic value of such an exercise electrocardiographic response.

  17. An integrally shielded transportable generator system for thallium-201 production.

    PubMed

    Lagunas-Solar, M C; Little, F E; Goodart, C D

    1982-12-01

    An integrally shielded transportable 201Pb leads to 201Tl generator system for the production of 201Tl has been developed at the Crocker Nuclear Laboratory, University of California, Davis. The present generator design allows for processing of up to 4 Ci of 201Pb parent radioactivity yielding approximately 400 mCi of 201Tl in a chemical form easily converted to radiopharmaceutical quality. Larger capacity generator systems can be constructed since the use of depleted uranium for shielding purposes is becoming readily available. While the parent 201Pb radioactivity decays to the daughter 201Tl, the combination depleted uranium-lead shielded system (approximately 33 kg) can be transported to distant locations for final processing. In this manner, decay losses (approximately 25%) associated with transportation of bulk 201Tl can be avoided since transportation would occur during the time (approximately 32 h) needed for the growth of 201Tl via 201Pb(9.4 h) leads to 201Tl (73.5 h). Single small-volume elutions (15-20 ml) provide more than 95% of the 201Tl radioactivity with no detectable radioactive Pb breakthrough and less than 20 micrograms/ml of carrier Tl.

  18. Non-invasive tissue temperature measurements based on quantitative diffuse optical spectroscopy (DOS) of water

    PubMed Central

    Chung, SH; Cerussi, AE; Merritt, SI; Ruth, J; Tromberg, BJ

    2012-01-01

    We describe the development of a non-invasive method for quantitative tissue temperature measurements using Broadband diffuse optical spectroscopy (DOS). Our approach is based on well-characterized opposing shifts in near-infrared (NIR) water absorption spectra that appear with temperature and macromolecular binding state. Unlike conventional reflectance methods, DOS is used to generate scattering-corrected tissue water absorption spectra. This allows us to separate the macromolecular bound water contribution from the thermally induced spectral shift using the temperature isosbestic point at 996 nm. The method was validated in intralipid tissue phantoms by correlating DOS with thermistor measurements (R = 0.96) with a difference of 1.1 ± 0.91 °C over a range of 28–48 °C. Once validated, thermal and hemodynamic (i.e. oxy- and deoxy-hemoglobin concentration) changes were measured simultaneously and continuously in human subjects (forearm) during mild cold stress. DOS-measured arm temperatures were consistent with previously reported invasive deep tissue temperature studies. These results suggest that DOS can be used for non-invasive, co-registered measurements of absolute temperature and hemoglobin parameters in thick tissues, a potentially important approach for optimizing thermal diagnostics and therapeutics. PMID:20551502

  19. Documenting 35 Years of Land Cover Change: Lago Cachet Dos Drainage, Chile

    NASA Astrophysics Data System (ADS)

    Friesen, B.; Nimick, D.; McGrath, D.; Cole, C.

    2014-12-01

    The U.S. Geological Survey (USGS) Special Applications Science Center is monitoring temporal changes at the Colonia Glacier and Lago Cachet Dos, Northern Patagonia Icefield of southern Chile. This location is one of the newest international sites in the USGS Global Fiducial Program (GFP)—a program which provides systematic monitoring of dynamic and environmentally critical areas with high-resolution imagery (http://gfp.usgs.gov/). In 2008, Lago Cachet Dos began experiencing glacial lake outburst floods (GLOFs) during which the entire pool of water (about 200 million m3) rapidly drains from the lake and flows south-southeast through the Colonia Glacier. These catastrophic events cause massive erosion of lake-bed and valley-fill deposits, and consequent upstream expansion of Lago Cachet Dos towards Lago Cachet Uno. Panchromatic and multispectral images for 1979, 2007, and 2014 highlight the dramatic changes that have occurred at this site over a 35-year period. The lake was smallest in 1979, when the Colonia Glacier was at its maximum thickness and extent during the study period. Between 1979 and 2007, the glacier shrank causing an increase in the surface area of the lake. The size of the lake increased substantially, from 2.98 km2 in 1979 to 4.41 km2 in 2014, primarily due to erosion of valley-fill deposits at its northern edge by the 15 GLOFs that occurred between April 2008 and February 2014. Ongoing studies of the Colonia Glacier and Lago Cachet Dos are focused on providing real-time monitoring of Lago Cachet Dos lake levels, understanding the history of advances and retreats of the Colonia Glacier, and determining the physical mechanisms and hazards associated with the GLOFs that come from Lago Cachet Dos.

  20. Documenting 35 years of land cover change: Lago Cachet Dos drainage, Chile

    USGS Publications Warehouse

    Friesen, Beverly A.; Nimick, David A.; Mcgrath, Daniel; Cole, Christopher J.; Wilson, Earl M.; Noble, Suzanne M.; Fahey, Mark J.; Leidich, Jonathan; O'Kuinghttons Villena, Jorge I.

    2015-01-01

    The U.S. Geological Survey (USGS) Special Applications Science Center is monitoring temporal changes at the Colonia Glacier and Lago Cachet Dos, Northern Patagonia Icefield of southern Chile. This location is one of the newest international sites in the USGS Global Fiducial Program (GFP)—a program which provides systematic monitoring of dynamic and environmentally critical areas with high-resolution imagery (http://gfp.usgs.gov/). In 2008, Lago Cachet Dos began experiencing glacial lake outburst floods (GLOFs) during which the entire pool of water (about 200 million cubic meters) rapidly drains from the lake and flows south-southeast through the Colonia Glacier. These catastrophic events cause massive erosion of valley-fill deposits and consequent upstream expansion of Lago Cachet Dos towards Lago Cachet Uno.  Panchromatic and multispectral images for 1979, 2007, and 2014 highlight the dramatic changes that have occurred at this site over a 35-year period. The lake was smallest in 1979, when the Colonia Glacier was at its maximum extent during the study period. Between 1979 and 2007, the glacier shrank causing an increase in the surface area of the lake. The size of the lake increased substantially, from 2.98 square kilometers (km2) in 1979 to 4.41 km2 in 2014, primarily due to erosion of valley-fill deposits upstream of its northern edge by the 15 GLOFs that occurred between April 2008 and February 2014. Ongoing studies of the Colonia Glacier and Lago Cachet Dos are focused on providing real-time monitoring of Lago Cachet Dos lake levels, understanding the history of advances and retreats of the Colonia Glacier, and determining the physical mechanisms and hazards associated with the GLOFs that come from Lago Cachet Dos.

  1. Reagent based DOS: a "Click, Click, Cyclize" strategy to probe chemical space.

    PubMed

    Rolfe, Alan; Lushington, Gerald H; Hanson, Paul R

    2010-05-01

    The synthesis of small organic molecules as probes for discovering new therapeutic agents has been an important aspect of chemical-biology. Herein we report a reagent-based, diversity-oriented synthetic (DOS) strategy to probe chemical and biological space via a "Click, Click, Cyclize" protocol. In this DOS approach, three sulfonamide linchpins underwent cyclization protocols with a variety of reagents to yield a collection of structurally diverse S-heterocycles. In silico analysis is utilized to evaluate the diversity of the compound collection against chemical space (PC analysis), shape space (PMI) and polar surface area (PSA) calculations.

  2. Entre Dos Mundos/Between Two Worlds: Youth Violence Prevention for Acculturating Latino Families

    ERIC Educational Resources Information Center

    Smokowski, Paul R.; Bacallao, Martica

    2009-01-01

    Objective: This study evaluated the efficacy of Entre Dos Mundos/Between Two Worlds (EDM) prevention for Latino adolescents. Method: In an experimental trial to compare implementation formats, 41 Latino families were randomly assigned to EDM action-oriented skills training groups, and 47 families were randomly assigned to unstructured EDM support…

  3. 33 CFR 106.250 - Declaration of Security (DoS).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Declaration of Security (DoS). 106.250 Section 106.250 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY MARITIME SECURITY MARINE SECURITY: OUTER CONTINENTAL SHELF (OCS) FACILITIES Outer Continental Shelf...

  4. 33 CFR 106.250 - Declaration of Security (DoS).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Declaration of Security (DoS). 106.250 Section 106.250 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY MARITIME SECURITY MARINE SECURITY: OUTER CONTINENTAL SHELF (OCS) FACILITIES Outer Continental Shelf...

  5. 33 CFR 106.250 - Declaration of Security (DoS).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Declaration of Security (DoS). 106.250 Section 106.250 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY MARITIME SECURITY MARINE SECURITY: OUTER CONTINENTAL SHELF (OCS) FACILITIES Outer Continental Shelf...

  6. 33 CFR 106.250 - Declaration of Security (DoS).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Declaration of Security (DoS). 106.250 Section 106.250 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY MARITIME SECURITY MARINE SECURITY: OUTER CONTINENTAL SHELF (OCS) FACILITIES Outer Continental Shelf...

  7. Low-Budget, Cost-Effective OCR: Optical Character Recognition for MS-DOS Micros.

    ERIC Educational Resources Information Center

    Perez, Ernest

    1990-01-01

    Discusses optical character recognition (OCR) for use with MS-DOS microcomputers. Cost effectiveness is considered, three types of software approaches to character recognition are explained, hardware and operation requirements are described, possible library applications are discussed, future OCR developments are suggested, and a list of OCR…

  8. Function, regulation and pathological roles of the Gab/DOS docking proteins

    PubMed Central

    2009-01-01

    Since their discovery a little more than a decade ago, the docking proteins of the Gab/DOS family have emerged as important signalling elements in metazoans. Gab/DOS proteins integrate and amplify signals from a wide variety of sources including growth factor, cytokine and antigen receptors as well as cell adhesion molecules. They also contribute to signal diversification by channelling the information from activated receptors into signalling pathways with distinct biological functions. Recent approaches in protein biochemistry and systems biology have revealed that Gab proteins are subject to complex regulation by feed-forward and feedback phosphorylation events as well as protein-protein interactions. Thus, Gab/DOS docking proteins are at the centre of entire signalling subsystems and fulfil an important if not essential role in many physiological processes. Furthermore, aberrant signalling by Gab proteins has been increasingly linked to human diseases from various forms of neoplasia to Alzheimer's disease. In this review, we provide a detailed overview of the structure, effector functions, regulation and evolution of the Gab/DOS family. We also summarize recent findings implicating Gab proteins, in particular the Gab2 isoform, in leukaemia, solid tumours and other human diseases. PMID:19737390

  9. MIIS to MS-DOS: Microcomputer Options for Online Catalog Support.

    ERIC Educational Resources Information Center

    Grotophorst, Clyde W.

    1986-01-01

    Describes use of personal computer at George Mason University to provide support to the online catalog. Merging of bibliographic information in MS-DOS format into database management system and experimentation with full-text retrieval packages (ZyIndex and SIRE) are discussed. Addresses and price information for hardware and software packages…

  10. Pygmy Rice Rat as Potential Host of Castelo dos Sonhos Hantavirus

    PubMed Central

    Travassos da Rosa, Elizabeth S.; Medeiros, Daniele B. A.; Nunes, Márcio R.T.; Simith, Darlene B.; Pereira, Armando de Souza; Elkhoury, Mauro R.; Lavocat, Marília; Marques, Aparecido A.R.; Via, Alba Valéria; D’Andrea, Paulo; Bonvicino, Cibele R.; Lemos, Elba Regina S.

    2011-01-01

    To study the dynamics of wild rodent populations and identify potential hosts for hantavirus, we conducted an eco-epidemiologic study in Campo Novo do Parecis, Mato Grosso State, Brazil. We detected and genetically characterized Castelo dos Sonhos virus found in a species of pygmy rice rat (Oligoryzomys utiaritensis). PMID:21801642

  11. Stretching the Software Dollar: MS-DOS Shareware and Public Domain Software.

    ERIC Educational Resources Information Center

    Grosch, Audrey N.

    1989-01-01

    Discusses shareware and public domain software for MS-DOS systems that are available through bulletin board systems (BBS). Problems with computer viruses are discussed; shareware available for communications, database and file management, spreadsheets, word processing, and menuing software is described; and source information for software is…

  12. MS DOS Tool Software Including Public Domain, Grades 6-12.

    ERIC Educational Resources Information Center

    New York City Board of Education, Brooklyn, NY.

    This curriculum guide is designed to assist teachers and supervisors in introducing middle and high school students to the MS DOS computer and its functional application software in word processing, database management, and spreadsheet analysis. The guide begins by introducing students to computers: when and how they are used, hardware and…

  13. Sedimentation survey of Lago Dos Bocas, Utuado, Puerto Rico, January 2010

    USGS Publications Warehouse

    Soler-López, Luis R.

    2014-01-01

    Lago Dos Bocas reservoir was completed in 1942 to provide water for hydroelectric power generation along the northern coast of Puerto Rico. The reservoir had an original storage capacity of 37.50 million cubic meters (Mm3). The dam is located about 9 kilometers (km) northeast of the town of Utuado, immediately downstream of the original confluence of the Río Grande de Arecibo and the Río Caonillas (fig. 1). The Puerto Rico Electric Power Authority (PREPA) owns and operates the Lago Dos Bocas reservoir, and since 1996, the reservoir has become an essential part of the Puerto Rico Aqueduct and Sewer Authority (PRASA) North Coast Superaqueduct Project. The Superaqueduct is supplied by controlled releases for hydroelectric power generation that replenish the public-supply raw-water intake pool located about 10 km downstream from the Lago Dos Bocas Dam (fig. 1). As of 2005, the Superaqueduct supplies about 4.03 cubic meters per second (m3/s) (348,192 cubic meters per day [m3/d]) of potable water to communities along the northern coast, from Arecibo to the San Juan metropolitan area. Because of the importance of the reservoir to the North Coast Superaqueduct, the U.S. Geological Survey (USGS), in cooperation with PRASA, conducted a sedimentation survey of Lago Dos Bocas in January 2009. The results of this survey were used to estimate the useful life and the firm yield of the reservoir, and evaluate the need to dredge the reservoir.

  14. Sedimentation History of Lago Dos Bocas, Puerto Rico, 1942-2005

    USGS Publications Warehouse

    Soler-López, Luis R.

    2007-01-01

    The Lago Dos Bocas Dam, located in the municipality of Utuado in north central Puerto Rico, was constructed in 1942 for hydroelectric power generation. The reservoir had an original storage capacity of 37.50 million cubic meters and a drainage area of 440 square kilometers. In 1948, the construction of the Lago Caonillas Dam on the Rio Caonillas branch of Lago Dos Bocas reduced the natural sediment-contributing drainage area to 310 square kilometers; therefore, the Lago Caonillas Dam is considered an effective sediment trap. Sedimentation in Lago Dos Bocas reservoir has reduced the storage capacity from 37.50 million cubic meters in 1942 to 17.26 million cubic meters in 2005, which represents a storage loss of about 54 percent. The long-term annual water-storage capacity loss rate remained nearly constant at about 320,000 cubic meters per year to about 1997. The inter-survey sedimentation rate between 1997 and 1999, however, is higher than the long-term rate at about 1.09 million cubic meters per year. Between 1999 and 2005 the rate is lower than the long-term rate at about 0.13 million cubic meters per year. The Lago Dos Bocas effective sediment-contributing drainage area had an average sediment yield of about 1,400 cubic meters per square kilometer per year between 1942 and 1997. This rate increased substantially by 1999 to about 4,600 cubic meters per square kilometer per year, probably resulting from the historical magnitude floods caused by Hurricane Georges in 1998. Recent data indicate that the Lago Dos Bocas drainage area sediment yield decreased substantially to about 570 cubic meters per square kilometer per year, which is much lower than the 1942-1997 area normalized sedimentation rate of 1,235 cubic meters per square kilometer per year. The impact of Hurricane Georges on the basin sediment yield could have been the cause of this change, since the magnitude of the floods could have nearly depleted the Lago Dos Bocas drainage area of easily erodible and

  15. First report of White spot syndrome virus in farmed and wild penaeid shrimp from lagoa dos patos estuary, southern brazil

    PubMed Central

    Cavalli, Lissandra Souto; Romano, Luis Alberto; Marins, Luis Fernando; Abreu, Paulo César

    2011-01-01

    In this study, we detected White spot syndrome virus (WSSV) in wild Farfantepenaeus paulensis collected in the Lagoa dos Patos estuary and cultivated Litopenaeus vannamei. This is the first report of WSSV in F. paulensis from Lagoa dos Patos and farmed L. vannamei shrimps in Rio Grande do Sul. PMID:24031739

  16. First report of White spot syndrome virus in farmed and wild penaeid shrimp from lagoa dos patos estuary, southern brazil.

    PubMed

    Cavalli, Lissandra Souto; Romano, Luis Alberto; Marins, Luis Fernando; Abreu, Paulo César

    2011-07-01

    In this study, we detected White spot syndrome virus (WSSV) in wild Farfantepenaeus paulensis collected in the Lagoa dos Patos estuary and cultivated Litopenaeus vannamei. This is the first report of WSSV in F. paulensis from Lagoa dos Patos and farmed L. vannamei shrimps in Rio Grande do Sul.

  17. Observational Assessment of Preschool Disruptive Behavior, Part II: Validity of the Disruptive Behavior Diagnostic Observation Schedule (DB-DOS)

    ERIC Educational Resources Information Center

    Wakschlag, Lauren S.; Briggs-Gowan, Margaret J.; Hill, Carri; Danis, Barbara; Leventhal, Bennett L.; Keenan, Kate; Egger, Helen L.; Cicchetti, Domenic; Burns, James; Carter, Alice S.

    2008-01-01

    A study is conducted to determine whether the multidomain, multicontext Disruptive Behavior Diagnostic Observation Schedule (DB-DOS) is a valid observational method for assessing disruptive behavior of preschool children. It is concluded that the DB-DOS is a valid method for a direct observational assessment of clinically significant disruptive…

  18. ACONF DOS

    2009-03-25

    ACONF is a system which has been developed by Sandia National Laboratories. ACONF is a system for optimizing the interaction between generator, photovoltaic system, batteries, and load in independent non-grid-tied electrical systems. It is primarily used in rural locations where running utility lines proves costly if it is possible at all. It is controlled by an Ampro PC-104 Coremodule 400 controller system. The code for this system is written in the BASIC programming language. Themore » routine contained in this document was written originally by Phil Symons. ACONF is intended to increase the efficiency of freestanding electrical systems to increase battery life and more efficiently use generator fuel.« less

  19. Using satellite images to monitor glacial-lake outburst floods: Lago Cachet Dos drainage, Chile

    USGS Publications Warehouse

    Friesen, Beverly A.; Cole, Christopher J.; Nimick, David A.; Wilson, Earl M.; Fahey, Mark J.; McGrath, Daniel J.; Leidich, Jonathan

    2015-01-01

    During 2008–2013, 14 GLOFs were released from Lago Cachet Dos and created environmental and safety concerns for downstream residents and to infrastructure. If GLOFs and the consequent headward erosion continue, the moraine that creates Lago Cachet Uno could be destabilized and breached, and the two lakes could merge. If the two lakes become connected, the volume of future GLOFs likely would be greater and thus cause longer and (or) more extensive flooding downstream. Additional GLOFs from Lago Cachet Dos are expected in the future, and continued environmental monitoring could provide an early warning system as well as scientific information that could increase our understanding of GLOFs and their consequences. GLOFs occur in glaciated areas around the world and remote sensing technologies can allow researchers to better understand—and potentially predict—future GLOF events.

  20. Protecting Web Services against DoS Attacks: A Case-Based Reasoning Approach

    NASA Astrophysics Data System (ADS)

    Pinzón, Cristian; de Paz, Juan F.; Zato, Carolina; Pérez, Javier

    The real-time detection is a key factor to detect and block DoS attacks within Web services. DoS attacks can be generated for different techniques that take advantage of points vulnerable within Web services. This paper describes a novel proposal based on a real time agent to classify user requests and detect and block malicious SOAP messages. The classification mechanism is based on a Case-Base Reasoning (CBR) model, where the different CBR phases are time bounded. Within the reuse phase of the CBR cycle is incorporated a mixture of experts to choose the most suitable technique of classification depending on the feature of the attack and the available time to solve the classification. A prototype of the architecture was developed and the results obtained are presented in this study.

  1. Perspectivas Futuras para o Observatório do Pico dos Dias

    NASA Astrophysics Data System (ADS)

    Bruch, Albert

    2004-02-01

    Com o Observatório Gemini plenamente operacional e o telescópio SOAR iniciando suas operações em breve, a astronomia observacional brasileira encontra-se no auge de uma transformação profunda que terá um impacto grave no Observatório do Pico dos Dias - OPD. Refletimos aqui sobre a natureza desse impacto e estratégias para manter a competitividade do OPD. Não queremos apresentar receitas prontas, mas idéias que poderão servir como base de discussão sobre o uso inteligente dos telescópios do OPD como parte do conjunto de instrumentos disponíveis à comunidade astronômica brasileira.

  2. An alternate hypothesis for the origin of Angra dos Reis - Porphyry, not cumulate

    NASA Technical Reports Server (NTRS)

    Treiman, A. H.

    1989-01-01

    The Angra dos Reis achondrite is a unique meteorite of potentially great importance for understanding the origins of the solar system and of the terrestrial planets. It is proposed that the meteorite, which consists of megacrysts of Al-Ti augite (fassaite) in skeletal or cellular shapes, olivine, and possibly whitlockite in a fine-grained groundmass of the same materials plus spinel, is a porphyritic igneous rock modified by metamorphism. In this interpretation, the megacrysts represent cellular-textured phenocrysts, and the fine-grain groundmass represents crystallized or devitrified magma. Phase equilibria suggest that Angra dos Reis-like compositions could grow phenocrysts of fassaite pyroxene, olivine, and whitlockite. These same compositions could crystallize, without crystal sorting or accumulation, to an almost monomineralic fassaite pyroxenite.

  3. Adaptive Suspicious Prevention for Defending DoS Attacks in SDN-Based Convergent Networks

    PubMed Central

    Dao, Nhu-Ngoc; Kim, Joongheon; Park, Minho; Cho, Sungrae

    2016-01-01

    The convergent communication network will play an important role as a single platform to unify heterogeneous networks and integrate emerging technologies and existing legacy networks. Although there have been proposed many feasible solutions, they could not become convergent frameworks since they mainly focused on converting functions between various protocols and interfaces in edge networks, and handling functions for multiple services in core networks, e.g., the Multi-protocol Label Switching (MPLS) technique. Software-defined networking (SDN), on the other hand, is expected to be the ideal future for the convergent network since it can provide a controllable, dynamic, and cost-effective network. However, SDN has an original structural vulnerability behind a lot of advantages, which is the centralized control plane. As the brains of the network, a controller manages the whole network, which is attractive to attackers. In this context, we proposes a novel solution called adaptive suspicious prevention (ASP) mechanism to protect the controller from the Denial of Service (DoS) attacks that could incapacitate an SDN. The ASP is integrated with OpenFlow protocol to detect and prevent DoS attacks effectively. Our comprehensive experimental results show that the ASP enhances the resilience of an SDN network against DoS attacks by up to 38%. PMID:27494411

  4. FlexyDos3D: a deformable anthropomorphic 3D radiation dosimeter: radiation properties

    NASA Astrophysics Data System (ADS)

    De Deene, Y.; Skyt, P. S.; Hil, R.; Booth, J. T.

    2015-02-01

    Three dimensional radiation dosimetry has received growing interest with the implementation of highly conformal radiotherapy treatments. The radiotherapy community faces new challenges with the commissioning of image guided and image gated radiotherapy treatments (IGRT) and deformable image registration software. A new three dimensional anthropomorphically shaped flexible dosimeter, further called ‘FlexyDos3D’, has been constructed and a new fast optical scanning method has been implemented that enables scanning of irregular shaped dosimeters. The FlexyDos3D phantom can be actuated and deformed during the actual treatment. FlexyDos3D offers the additional advantage that it is easy to fabricate, is non-toxic and can be molded in an arbitrary shape with high geometrical precision. The dosimeter formulation has been optimized in terms of dose sensitivity. The influence of the casting material and oxygen concentration has also been investigated. The radiophysical properties of this new dosimeter are discussed including stability, spatial integrity, temperature dependence of the dosimeter during radiation, readout and storage, dose rate dependence and tissue equivalence. The first authors Y De Deene and P S Skyt made an equivalent contribution to the experimental work presented in this paper.

  5. Adaptive Suspicious Prevention for Defending DoS Attacks in SDN-Based Convergent Networks.

    PubMed

    Dao, Nhu-Ngoc; Kim, Joongheon; Park, Minho; Cho, Sungrae

    2016-01-01

    The convergent communication network will play an important role as a single platform to unify heterogeneous networks and integrate emerging technologies and existing legacy networks. Although there have been proposed many feasible solutions, they could not become convergent frameworks since they mainly focused on converting functions between various protocols and interfaces in edge networks, and handling functions for multiple services in core networks, e.g., the Multi-protocol Label Switching (MPLS) technique. Software-defined networking (SDN), on the other hand, is expected to be the ideal future for the convergent network since it can provide a controllable, dynamic, and cost-effective network. However, SDN has an original structural vulnerability behind a lot of advantages, which is the centralized control plane. As the brains of the network, a controller manages the whole network, which is attractive to attackers. In this context, we proposes a novel solution called adaptive suspicious prevention (ASP) mechanism to protect the controller from the Denial of Service (DoS) attacks that could incapacitate an SDN. The ASP is integrated with OpenFlow protocol to detect and prevent DoS attacks effectively. Our comprehensive experimental results show that the ASP enhances the resilience of an SDN network against DoS attacks by up to 38%. PMID:27494411

  6. Adaptive Suspicious Prevention for Defending DoS Attacks in SDN-Based Convergent Networks.

    PubMed

    Dao, Nhu-Ngoc; Kim, Joongheon; Park, Minho; Cho, Sungrae

    2016-01-01

    The convergent communication network will play an important role as a single platform to unify heterogeneous networks and integrate emerging technologies and existing legacy networks. Although there have been proposed many feasible solutions, they could not become convergent frameworks since they mainly focused on converting functions between various protocols and interfaces in edge networks, and handling functions for multiple services in core networks, e.g., the Multi-protocol Label Switching (MPLS) technique. Software-defined networking (SDN), on the other hand, is expected to be the ideal future for the convergent network since it can provide a controllable, dynamic, and cost-effective network. However, SDN has an original structural vulnerability behind a lot of advantages, which is the centralized control plane. As the brains of the network, a controller manages the whole network, which is attractive to attackers. In this context, we proposes a novel solution called adaptive suspicious prevention (ASP) mechanism to protect the controller from the Denial of Service (DoS) attacks that could incapacitate an SDN. The ASP is integrated with OpenFlow protocol to detect and prevent DoS attacks effectively. Our comprehensive experimental results show that the ASP enhances the resilience of an SDN network against DoS attacks by up to 38%.

  7. Fast washout of thallium-201 from area of myocardial infarction: possible artifact of background subtraction

    SciTech Connect

    Brown, K.A.; Benoit, L.; Clements, J.P.; Wackers, F.J.

    1987-06-01

    A recent report described a pattern of reverse redistribution on poststreptokinase /sup 201/Tl studies which was believed to be due to rapid washout of /sup 201/Tl from the infarct area related to reperfusion of the infarct vessel. We have also observed the phenomenon of rapid washout of /sup 201/Tl from the area of infarction in the absence of thrombolytic therapy. This study was undertaken to test the hypothesis that rapid washout of /sup 201/Tl from an area of infarction is an artifact of background subtraction usually employed in analysis of washout. A total of 61 patients with previous myocardial infarction who underwent cardiac catheterization and exercise /sup 201/Tl imaging were examined. Thallium-201 images were analyzed using a validated quantitative method employing interpolative background correction. Abnormally increased /sup 201/Tl washout was noted in 11 infarct segments in 10 (18%) patients. Infarct segments with rapid washout had significantly less initial uptake, and more severe associated wall motion abnormalities than infarct segments with normal washout. When quantitative analysis was repeated without background subtraction, no segments with rapid washout were observed. A phantom model was constructed to further test our hypothesis. The frequency of observed rapid washout was directly related to the severity of the initial defect and was entirely dependent upon utilizing background correction during the quantitative analysis. Our study suggests that rapid washout of /sup 201/Tl in an area of previous infarction reflects an artifact of background subtraction involved with standard quantitative analysis.

  8. Effect of thallium-201 blood levels on reversible myocardial defects

    SciTech Connect

    Nelson, C.W.; Wilson, R.A.; Angello, D.A.; Palac, R.T.

    1989-07-01

    To determine if /sup 201/Tl plasma blood levels correlate with the presence of reversible myocardial defects during exercise testing, 14 patients with stable coronary artery disease underwent two separate exercise /sup 201/Tl stress tests. Between initial and delayed imaging, on one test the patients drank an instant breakfast drink (eating) and on the other they drank an equivalent volume of water as a control (H/sub 2/O). Thallium-201 imaging was performed immediately postexercise, immediately after eating/H/sub 2/O and 210 min after eating/H/sub 2/O. Between initial and immediate post eating/H/sub 2/O images 201Tl reversible defects occurred in 27/38 regions in the H/sub 2/O test versus 15/38 regions in the eating test (p = 0.02). Over this early time period, plasma /sup 201/Tl activity was significantly higher in the H/sub 2/O test than eating test (p less than 0.05). In conclusion, early reversal of /sup 201/Tl defects may, in part, be the result of higher plasma /sup 201/Tl activity early after initial postexercise /sup 201/Tl imaging.

  9. Using 4DOS Batch Files To Create an Infrastructure That Makes It Easy for Students To Create and Maintain HTML Web Pages.

    ERIC Educational Resources Information Center

    Snyder, Robin M.

    This paper describes the use of simple 4DOS batch files to automate the creation and maintenance of an infrastructure to assist students in creating and maintaining HTML World Wide Web pages. Background is provided on Web pages, DOS, 4DOS, and batch files. The assumptions made in creating the infrastructure are summarized, and program statements…

  10. T cell responses to DosR and Rpf proteins in actively and latently infected individuals from Colombia.

    PubMed

    Riaño, Felipe; Arroyo, Leonar; París, Sara; Rojas, Mauricio; Friggen, Annemieke H; van Meijgaarden, Krista E; Franken, Kees L M C; Ottenhoff, Tom H M; García, Luis F; Barrera, Luis F

    2012-03-01

    Mycobacterium tuberculosis DosR regulon-encoded proteins elicit strong immune T-cell responses in individuals with latent tuberculosis (LTBI). Also, resuscitation (Rpf) proteins can induce such responses. However, variations in the immunogenicity of the DosR and Rpf proteins have been observed in European and African populations, and no data are published from other geographic areas. In Colombian LTBI and patients with recently diagnosed PTB, we therefore studied the immune response to DosR, Rpf, stress, and nominal antigens from Mtb, in 7-day stimulated cultures. Three DosR (Rv1737c, Rv2029c, Rv2628c) and 2 Rpf (Rv0867 and Rv2389c) antigens were recognized most prominently on the basis of the net IFNγ production (DosR) or the percentage of responding individuals (Rpf). Results show that the selected DosR antigens induced a higher proportion of CD4-T cells producing IFNγ from LTBI, compared to pulmonary TB patients (PTB), while there were no differences in the proportion of CD8-T cells. An increased frequency of CD4, but not CD8 T-cells with a CD45RO(+)CD27(+) phenotype was observed in LTBI in response to Rv2029c, Rv0867c, and Rv2389c, compared to PTB. The levels of cytokines and chemokines in the supernatants of stimulated cells, showed that the DosR and Rpf antigens induced higher levels of IFNγ in cultures from LTBI compared to PTB, although the induced pattern of cytokines and chemokines was also antigen dependent. In summary, our results are consistent with the significant immunogenicity of Mtb DosR and Rpf antigens in LTBI individuals, and confirm and extend previously reported data from other TB affected human populations.

  11. Thallium-201/technetium-99m-RP-30A disparity in the course of myocardial infarction after attempted reperfusion

    SciTech Connect

    Tatum, J.L.; Rehr, R.B.; DiSciascio, G.; Romhilt, D.W.; Fratkin, M.J.

    1988-07-01

    Recent reports have established that /sup 201/Tl may be taken up in areas of recent myocardial infarction after myocardial blood flow is re-established. In addition, there is accelerated /sup 201/Tl washout from these regions producing a pattern of reverse redistribution. We present a case in which these phenomena may have contributed to a disparity of findings between a /sup 201/Tl stress imaging study and a repeat stress imaging study performed with a (/sup 99m/Tc) isonitrile (/sup 99m/Tc-RP-30A).

  12. DoS detection in IEEE 802.11 with the presence of hidden nodes.

    PubMed

    Soryal, Joseph; Liu, Xijie; Saadawi, Tarek

    2014-07-01

    The paper presents a novel technique to detect Denial of Service (DoS) attacks applied by misbehaving nodes in wireless networks with the presence of hidden nodes employing the widely used IEEE 802.11 Distributed Coordination Function (DCF) protocols described in the IEEE standard [1]. Attacker nodes alter the IEEE 802.11 DCF firmware to illicitly capture the channel via elevating the probability of the average number of packets transmitted successfully using up the bandwidth share of the innocent nodes that follow the protocol standards. We obtained the theoretical network throughput by solving two-dimensional Markov Chain model as described by Bianchi [2], and Liu and Saadawi [3] to determine the channel capacity. We validated the results obtained via the theoretical computations with the results obtained by OPNET simulator [4] to define the baseline for the average attainable throughput in the channel under standard conditions where all nodes follow the standards. The main goal of the DoS attacker is to prevent the innocent nodes from accessing the channel and by capturing the channel's bandwidth. In addition, the attacker strives to appear as an innocent node that follows the standards. The protocol resides in every node to enable each node to police other nodes in its immediate wireless coverage area. All innocent nodes are able to detect and identify the DoS attacker in its wireless coverage area. We applied the protocol to two Physical Layer technologies: Direct Sequence Spread Spectrum (DSSS) and Frequency Hopping Spread Spectrum (FHSS) and the results are presented to validate the algorithm.

  13. DoS detection in IEEE 802.11 with the presence of hidden nodes.

    PubMed

    Soryal, Joseph; Liu, Xijie; Saadawi, Tarek

    2014-07-01

    The paper presents a novel technique to detect Denial of Service (DoS) attacks applied by misbehaving nodes in wireless networks with the presence of hidden nodes employing the widely used IEEE 802.11 Distributed Coordination Function (DCF) protocols described in the IEEE standard [1]. Attacker nodes alter the IEEE 802.11 DCF firmware to illicitly capture the channel via elevating the probability of the average number of packets transmitted successfully using up the bandwidth share of the innocent nodes that follow the protocol standards. We obtained the theoretical network throughput by solving two-dimensional Markov Chain model as described by Bianchi [2], and Liu and Saadawi [3] to determine the channel capacity. We validated the results obtained via the theoretical computations with the results obtained by OPNET simulator [4] to define the baseline for the average attainable throughput in the channel under standard conditions where all nodes follow the standards. The main goal of the DoS attacker is to prevent the innocent nodes from accessing the channel and by capturing the channel's bandwidth. In addition, the attacker strives to appear as an innocent node that follows the standards. The protocol resides in every node to enable each node to police other nodes in its immediate wireless coverage area. All innocent nodes are able to detect and identify the DoS attacker in its wireless coverage area. We applied the protocol to two Physical Layer technologies: Direct Sequence Spread Spectrum (DSSS) and Frequency Hopping Spread Spectrum (FHSS) and the results are presented to validate the algorithm. PMID:25685510

  14. DoS detection in IEEE 802.11 with the presence of hidden nodes

    PubMed Central

    Soryal, Joseph; Liu, Xijie; Saadawi, Tarek

    2013-01-01

    The paper presents a novel technique to detect Denial of Service (DoS) attacks applied by misbehaving nodes in wireless networks with the presence of hidden nodes employing the widely used IEEE 802.11 Distributed Coordination Function (DCF) protocols described in the IEEE standard [1]. Attacker nodes alter the IEEE 802.11 DCF firmware to illicitly capture the channel via elevating the probability of the average number of packets transmitted successfully using up the bandwidth share of the innocent nodes that follow the protocol standards. We obtained the theoretical network throughput by solving two-dimensional Markov Chain model as described by Bianchi [2], and Liu and Saadawi [3] to determine the channel capacity. We validated the results obtained via the theoretical computations with the results obtained by OPNET simulator [4] to define the baseline for the average attainable throughput in the channel under standard conditions where all nodes follow the standards. The main goal of the DoS attacker is to prevent the innocent nodes from accessing the channel and by capturing the channel’s bandwidth. In addition, the attacker strives to appear as an innocent node that follows the standards. The protocol resides in every node to enable each node to police other nodes in its immediate wireless coverage area. All innocent nodes are able to detect and identify the DoS attacker in its wireless coverage area. We applied the protocol to two Physical Layer technologies: Direct Sequence Spread Spectrum (DSSS) and Frequency Hopping Spread Spectrum (FHSS) and the results are presented to validate the algorithm. PMID:25685510

  15. Volcanic and structural controls of mineralization in the Dos Cabezas Mountains of southeastern Arizona

    SciTech Connect

    Drewes, H.; Klein, D.P.; Birmingham, S.D.

    1988-01-01

    A combination of geophysical, geochemical, and geological features suggests that a central part of the Dos Cabezas Mountains probably has considerable potential for blind deposits, chiefly base metals. The area exposes the root zone of a Paleocene( ) volcanic complex and its underlying granitic stocks, which were emplaced next to a major northwest-trending, much reactivated fault zone. The new data, combined with the knowledge of past mining activity in the area, lead them to propose several exploration targets that may lead to ore bodies in breccia pipes along the base of the volcanic pile and along a possible concealed fault or caldera margin.

  16. Use of Remote Sensing and Local Knowledge for Geoconservation of Regiao dos Lagos, Brazil

    NASA Astrophysics Data System (ADS)

    Avelar, S.; Vasconcelos, G.; Mansur, K. L.; Anjos, S. C.

    2013-12-01

    A series of lagoons can be found along the coastline of Rio de Janeiro, in the so-called Regiao dos Lagos. The lagoons differ in size, physicochemical, sedimentological and biological characteristics. Rare examples of litifying microbialites that produce stromatolites, the oldest fossils on Earth, can be found living in this lagoon system. The occurrence of stromatolites in the region is of great scientific interest because it enables the study of possible analogues of the earliest life on Earth. However, this region has been suffering from intense human activities and degradations. Geoconservation planning requires an assessment of the characteristics of the region and its potential threats. The primary goal of this study is to assess physical environmental changes and anthropogenic impacts over the last four decades in Regiao dos Lagos. Using a broad integrative assessment combining remote sensing, GIS, field studies and local knowledge of communities, land-cover and land-use classes were identified, as well as the main human activities impacting the environment. The seasonal and weekend tourism and urban sprawl in this coastal area of Rio de Janeiro triggers the occupation of new areas and the removal of natural vegetation, especially on lagoon margins. This disorderly occupation by an ever increasing population, with both legal and illegal constructions and the subsequent overload of the local infrastructure, e.g. increase of electrical energy consumption, volume of vehicles, pollution in air, water and soil and problems with water supply and wastewater treatment, are hastening the gradual degradation of the lake ecosystem. The main driving forces to environmental changes over the last four decades in Regiao dos Lagos were the change of dense vegetation, saline and bare soil classes into built-up areas, adding to the poor waste treatment and inadequate sewage disposal. This analysis provides a basis for a better control of anthropogenic impacts and

  17. Age and isotopic relationships among the angrites Lewis Cliff 86010 and Angra dos Reis

    SciTech Connect

    Lugmair, G.W. ); Galer, S.J.G. Max-Planck-Inst. fuer Chemie, Mainz )

    1992-04-01

    Results of a wide-ranging isotopic investigation of the unique Antarctican angrite LEW-86010 (LEW) are presented, together with a reassessment of the type angrite Angra dos Reis (ADOR). The principal objectives of this study are to obtain precise radiometric ages, initial Sr isotopic compositions, and to search for the erstwhile presence of the short-lived nuclei {sup 146}Sm and {sup 26}Al via their daughter products. The isotopic compositions of Sm, U, Ca, and Ti were also measured. This allows a detailed appraisal to be made of the relations between, and the genealogy of, these two angrites.

  18. Studies of Brazilian meteorites. III - Origin and history of the Angra dos Reis achondrite

    NASA Technical Reports Server (NTRS)

    Prinz, M.; Keil, K.; Hlava, P. F.; Berkley, J. L.; Gomes, C. B.; Curvello, W. S.

    1977-01-01

    The mineral composition of the Angra dos Reis meteorite, which fell in 1869, is described. This achondrite contains phases reported in a meteorite for the first time. Petrofabric analysis shows that fassaite has a preferred orientation and lineation, which is interpreted as being due to cumulus processes, possibly the effect of post-depositional magmatic current flow or laminar flow of a crystalline mush. The mineral chemistry indicates crystallization from a highly silica-undersaturated melt at low pressure. Several aspects of the mineral composition are discussed with reference to the implications of crystallization conditions.

  19. Electron spin resonance dating of megafauna from Lagoa dos Porcos, Piauí, Brazil.

    PubMed

    Kinoshita, Angela; Mayer, Elver; Ribau Mendes, Vinícius; Figueiredo, Ana Maria G; Baffa, Oswaldo

    2014-06-01

    Excavations performed at Lagoa dos Porcos site revealed a vast amount of extinct mammal fossil remains, becoming one of the richest palaeontological occurrences in the Serra da Capivara National Park region, a UNESCO World Heritage. Although anatomic and taxonomic aspects of extinct Quaternary mammals are relatively well known, chronologic information for deposits is rare. In this context, electron spin resonance (ESR) dating of megafauna samples provides important information for establishing a chronological background. This work presents the ESR dating of two teeth, one of Gomphotheriidae and other of Toxodontinae. Dose-response curves of each sample were constructed using spectra acquired with a JEOL FA-200 X-Band spectrometer resulting in equivalent dose (De) of 220 ± 40 Gy and 39 ± 2 Gy for Toxodontinae and Gomphotheriidae tooth, respectively. The conversion of De in age was made using ROSY ESR dating software resulting in 26 ± 4 and 22 ± 3 ka. These results place Lagoa dos Porcos fossil assemblage within the Late Pleistocene. These dates overlap with a period of abrupt increase in rainfall in northeast Brazil, and it is possible that this environmental change is related to the formation of this deposit.

  20. RighTime: A real time clock correcting program for MS-DOS-based computer systems

    NASA Technical Reports Server (NTRS)

    Becker, G. Thomas

    1993-01-01

    A computer program is described which effectively eliminates the misgivings of the DOS system clock in PC/AT-class computers. RighTime is a small, sophisticated memory-resident program that automatically corrects both the DOS system clock and the hardware 'CMOS' real time clock (RTC) in real time. RighTime learns what corrections are required without operator interaction beyond the occasional accurate time set. Both warm (power on) and cool (power off) errors are corrected, usually yielding better than one part per million accuracy in the typical desktop computer with no additional hardware, and RighTime increases the system clock resolution from approximately 0.0549 second to 0.01 second. Program tools are also available which allow visualization of RighTime's actions, verification of its performance, display of its history log, and which provide data for graphing of the system clock behavior. The program has found application in a wide variety of industries, including astronomy, satellite tracking, communications, broadcasting, transportation, public utilities, manufacturing, medicine, and the military.

  1. Quality control and assurance for validation of DOS/I measurements

    NASA Astrophysics Data System (ADS)

    Cerussi, Albert; Durkin, Amanda; Kwong, Richard; Quang, Timothy; Hill, Brian; Tromberg, Bruce J.; MacKinnon, Nick; Mantulin, William W.

    2010-02-01

    Ongoing multi-center clinical trials are crucial for Biophotonics to gain acceptance in medical imaging. In these trials, quality control (QC) and assurance (QA) are key to success and provide "data insurance". Quality control and assurance deal with standardization, validation, and compliance of procedures, materials and instrumentation. Specifically, QC/QA involves systematic assessment of testing materials, instrumentation performance, standard operating procedures, data logging, analysis, and reporting. QC and QA are important for FDA accreditation and acceptance by the clinical community. Our Biophotonics research in the Network for Translational Research in Optical Imaging (NTROI) program for breast cancer characterization focuses on QA/QC issues primarily related to the broadband Diffuse Optical Spectroscopy and Imaging (DOS/I) instrumentation, because this is an emerging technology with limited standardized QC/QA in place. In the multi-center trial environment, we implement QA/QC procedures: 1. Standardize and validate calibration standards and procedures. (DOS/I technology requires both frequency domain and spectral calibration procedures using tissue simulating phantoms and reflectance standards, respectively.) 2. Standardize and validate data acquisition, processing and visualization (optimize instrument software-EZDOS; centralize data processing) 3. Monitor, catalog and maintain instrument performance (document performance; modularize maintenance; integrate new technology) 4. Standardize and coordinate trial data entry (from individual sites) into centralized database 5. Monitor, audit and communicate all research procedures (database, teleconferences, training sessions) between participants ensuring "calibration". This manuscript describes our ongoing efforts, successes and challenges implementing these strategies.

  2. Dosimetry and Vibration measurements in BIOLAB and EMCS (Dos-ViBE)

    NASA Astrophysics Data System (ADS)

    Ideström, Johan Olof; Hendrik Anken, Ralf; Reitz, Guenther; Berger, Thomas; Hauslage, Jens; Schuber, Marianne; Fossum, Knut R.; Vanhavere, Filip

    Space irradiation and vibrations in even small dosages can impact biological experiments and have not yet been measured in the biological payloads of the Columbus module at the Interna-tional Space Station (ISS). Installing active dosimeters and accelerometers in the Experiment Containers (EC) of Biolab and the European Modular Cultivation System (EMCS), to sur-vey in-situ the radiation and vibrations in these facilities, should be performed to serve as a reference of the space conditions to future experiments. To monitor the radiation field, the space radiation should be measured with an active dosime-ter inside the Multi-User-Facilities, as close to the actual shielding conditions of the biological experiments as possible. To measure the full spectrum of vibration frequencies, several instru-ments with different measurement ranges and sensitivity should be combined. The radiation and vibrations should be measured simultaneously in Biolab and EMCS to compare their radiation shielding and sensitivities to vibrations from the ISS. The radiation could also be measured with passive dosimeters. On the one hand this would be a back-up to the active dosimeter and on the other hand it would provide additional data since the passive dosimeters can give additional information on the radiation LET spectrum. As a response to ESA's Announcement of Opportunity (ILSRA-2009), a joint experiment in Biolab and EMCS, entitled Dos-ViBE, was proposed by the co-authors. The objectives and experimental flow of Dos-ViBE are outlined in this presentation.

  3. Crystal Structures of the Response Regulator DosR From Mycobacterium Tuberculosis Suggest a Helix Rearrangement Mechanism for Phosphorylation Activation

    SciTech Connect

    Wisedchaisri, G.; Wu, M.; Sherman, D.R.; Hol, W.G.J.

    2009-05-26

    The response regulator DosR is essential for promoting long-term survival of Mycobacterium tuberculosis under low oxygen conditions in a dormant state and may be responsible for latent tuberculosis in one-third of the world's population. Here, we report crystal structures of full-length unphosphorylated DosR at 2.2 {angstrom} resolution and its C-terminal DNA-binding domain at 1.7 {angstrom} resolution. The full-length DosR structure reveals several features never seen before in other response regulators. The N-terminal domain of the full-length DosR structure has an unexpected ({beta}{alpha}){sub 4} topology instead of the canonical ({beta}{alpha}){sub 5} fold observed in other response regulators. The linker region adopts a unique conformation that contains two helices forming a four-helix bundle with two helices from another subunit, resulting in dimer formation. The C-terminal domain in the full-length DosR structure displays a novel location of helix {alpha}10, which allows Gln199 to interact with the catalytic Asp54 residue of the N-terminal domain. In contrast, the structure of the DosR C-terminal domain alone displays a remarkable unstructured conformation for helix {alpha}10 residues, different from the well-defined helical conformations in all other known structures, indicating considerable flexibility within the C-terminal domain. Our structures suggest a mode of DosR activation by phosphorylation via a helix rearrangement mechanism.

  4. Serine 83 in DosR, a response regulator from Mycobacterium tuberculosis, promotes its transition from an activated, phosphorylated state to an inactive, unphosphorylated state.

    PubMed

    Cho, Ha Yeon; Kang, Beom Sik

    2014-02-21

    A sensor kinase, DosS, and its corresponding response regulator, DosR, constitute a two component system for regulating gene expression under hypoxic conditions in Mycobacterium tuberculosis. Among response regulators in M. tuberculosis, NarL has high sequence similarity to DosR, and autophosphorylated DosS transfers its phosphate group not only to DosR but also to NarL. Phosphorylated DosR is more rapidly dephosphorylated than phosphorylated NarL. DosR and NarL differ with respect to the amino acids at positions T+1 and T+2 around the phosphorylation sites in the N-terminal phosphoacceptor domain; NarL has S83 and Y84, whereas DosR has A90 and H91. A DosR S83A mutant shows prolonged phosphorylation. Structural comparison with a histidinol phosphate phosphatase suggests that the hydroxyl group of DosR S83 could play a role in activating the water molecule involved in the triggering of autodephosphorylation.

  5. A Direct Method to Extract Transient Sub-Gap Density of State (DOS) Based on Dual Gate Pulse Spectroscopy

    PubMed Central

    Dai, Mingzhi; Khan, Karim; Zhang, Shengnan; Jiang, Kemin; Zhang, Xingye; Wang, Weiliang; Liang, Lingyan; Cao, Hongtao; Wang, Pengjun; Wang, Peng; Miao, Lijing; Qin, Haiming; Jiang, Jun; Xue, Lixin; Chu, Junhao

    2016-01-01

    Sub-gap density of states (DOS) is a key parameter to impact the electrical characteristics of semiconductor materials-based transistors in integrated circuits. Previously, spectroscopy methodologies for DOS extractions include the static methods, temperature dependent spectroscopy and photonic spectroscopy. However, they might involve lots of assumptions, calculations, temperature or optical impacts into the intrinsic distribution of DOS along the bandgap of the materials. A direct and simpler method is developed to extract the DOS distribution from amorphous oxide-based thin-film transistors (TFTs) based on Dual gate pulse spectroscopy (GPS), introducing less extrinsic factors such as temperature and laborious numerical mathematical analysis than conventional methods. From this direct measurement, the sub-gap DOS distribution shows a peak value on the band-gap edge and in the order of 1017–1021/(cm3·eV), which is consistent with the previous results. The results could be described with the model involving both Gaussian and exponential components. This tool is useful as a diagnostics for the electrical properties of oxide materials and this study will benefit their modeling and improvement of the electrical properties and thus broaden their applications. PMID:27297030

  6. DOS-HEATING6: A general conduction code with nuclear heat generation derived from DOT-IV transport calculations

    SciTech Connect

    Williams, M.L.; Yuecel, A.; Nadkarny, S.

    1988-05-01

    The HEATING6 heat conduction code is modified to (a) read the multigroup particle fluxes from a two-dimensional DOT-IV neutron- photon transport calculation, (b) interpolate the fluxes from the DOT-IV variable (optional) mesh to the HEATING6 control volume mesh, and (c) fold the interpolated fluxes with kerma factors to obtain a nuclear heating source for the heat conduction equation. The modified HEATING6 is placed as a module in the ORNL discrete ordinates system (DOS), and has been renamed DOS-HEATING6. DOS-HEATING6 provides the capability for determining temperature distributions due to nuclear heating in complex, multi-dimensional systems. All of the original capabilities of HEATING6 are retained for the nuclear heating calculation; e.g., generalized boundary conditions (convective, radiative, finned, fixed temperature or heat flux), temperature and space dependent thermal properties, steady-state or transient analysis, general geometry description, etc. The numerical techniques used in the code are reviewed and the user input instructions and JCL to perform DOS-HEATING6 calculations are presented. Finally a sample problem involving coupled DOT-IV and DOS-HEATING6 calculations of a complex space-reactor configurations described, and the input and output of the calculations are listed. 10 refs., 11 figs., 6 tabs.

  7. A Direct Method to Extract Transient Sub-Gap Density of State (DOS) Based on Dual Gate Pulse Spectroscopy

    NASA Astrophysics Data System (ADS)

    Dai, Mingzhi; Khan, Karim; Zhang, Shengnan; Jiang, Kemin; Zhang, Xingye; Wang, Weiliang; Liang, Lingyan; Cao, Hongtao; Wang, Pengjun; Wang, Peng; Miao, Lijing; Qin, Haiming; Jiang, Jun; Xue, Lixin; Chu, Junhao

    2016-06-01

    Sub-gap density of states (DOS) is a key parameter to impact the electrical characteristics of semiconductor materials-based transistors in integrated circuits. Previously, spectroscopy methodologies for DOS extractions include the static methods, temperature dependent spectroscopy and photonic spectroscopy. However, they might involve lots of assumptions, calculations, temperature or optical impacts into the intrinsic distribution of DOS along the bandgap of the materials. A direct and simpler method is developed to extract the DOS distribution from amorphous oxide-based thin-film transistors (TFTs) based on Dual gate pulse spectroscopy (GPS), introducing less extrinsic factors such as temperature and laborious numerical mathematical analysis than conventional methods. From this direct measurement, the sub-gap DOS distribution shows a peak value on the band-gap edge and in the order of 1017–1021/(cm3·eV), which is consistent with the previous results. The results could be described with the model involving both Gaussian and exponential components. This tool is useful as a diagnostics for the electrical properties of oxide materials and this study will benefit their modeling and improvement of the electrical properties and thus broaden their applications.

  8. An MS-DOS-based program for analyzing plutonium gamma-ray spectra

    SciTech Connect

    Ruhter, W.D.; Buckley, W.M.

    1989-09-07

    A plutonium gamma-ray analysis system that operates on MS-DOS-based computers has been developed for the International Atomic Energy Agency (IAEA) to perform in-field analysis of plutonium gamma-ray spectra for plutonium isotopics. The program titled IAEAPU consists of three separate applications: a data-transfer application for transferring spectral data from a CICERO multichannel analyzer to a binary data file, a data-analysis application to analyze plutonium gamma-ray spectra, for plutonium isotopic ratios and weight percents of total plutonium, and a data-quality assurance application to check spectral data for proper data-acquisition setup and performance. Volume 3 contains the software listings for these applications.

  9. On securing wireless sensor network--novel authentication scheme against DOS attacks.

    PubMed

    Raja, K Nirmal; Beno, M Marsaline

    2014-10-01

    Wireless sensor networks are generally deployed for collecting data from various environments. Several applications specific sensor network cryptography algorithms have been proposed in research. However WSN's has many constrictions, including low computation capability, less memory, limited energy resources, vulnerability to physical capture, which enforce unique security challenges needs to make a lot of improvements. This paper presents a novel security mechanism and algorithm for wireless sensor network security and also an application of this algorithm. The proposed scheme is given to strong authentication against Denial of Service Attacks (DOS). The scheme is simulated using network simulator2 (NS2). Then this scheme is analyzed based on the network packet delivery ratio and found that throughput has improved.

  10. The Secret List of Dos and Don'ts for Filmmaking

    NASA Astrophysics Data System (ADS)

    Kramer, N.

    2012-12-01

    Science is a massive black box to billions of people who walk the streets. However, the process of filmmaking can be equally as mystifying. As with the development of many scientific experiments, the process starts on a napkin at a restaurant…but then what? The road to scientific publication is propelled by a canonical list of several dos and don't that fit most situations. An equally useful list exists for up-and-coming producers. The list streamlines efforts, optimizes your use of the tools at your fingertips and enhances impact. Many fundamentals can be learned from books, but during this talk we will project and discuss several examples of best practices, from honing a story, to identifying audience appeal, filming, editing and the secrets of inexpensively acquiring expert help. Whether your goal is a two-minute webisode or a 90 minute documentary, these time-tested practices, with a little awareness, can give life to your films.;

  11. Estudio dinámico de un potencial perturbador dependiente de dos parámetros

    NASA Astrophysics Data System (ADS)

    Miloni, O.; Brunini, A.

    El objeto del presente trabajo consiste en el estudio dinámico de un sistema dinámico caracterizado por la función hamiltoniana correspondiente a un satélite planetario perturbado por la acción del Sol y del achatamiento del planeta madre. Cuando dicha Hamiltoniana se promedia respecto de los términos de corto período, esta queda con dos grados de libertad, y su estudio puede ser realizado con las herramientas clásicas de la dinámica no-lineal. Se tratará de determinar regiones regulares y caóticas de movimiento. En el caso de estas últimas, es de particular interés la determinación de su orígen.

  12. Sm-Nd-Pu timepieces in the Angra dos Reis meteorite

    NASA Technical Reports Server (NTRS)

    Lugmair, G. W.; Marti, K.

    1977-01-01

    Isotope ratios and age estimations are presented for the ultramafic pyroxenite Angra dos Reis meteorite. A pyroxene-phosphate internal isochron age of 4.55 plus or minus 0.04 eons was obtained, in agreement with reported Pb-Pb ages. It is suggested that Sm-146 decay led to an increase in the ratio of Nd-142 to Nd-144 in pyroxene, which is greater than the ratio of the Nd isotopes in phosphates. The effect of Pu-244 on the fission xenon components in pyroxene and phosphate is examined. The ratios of Pu-244 to Nd, U-238, and Th-232 are compared for pyroxene and phosphate separates. The exposure age of the meteorite, as obtained by the Kr-81 to Kr-83 method, was found to be 55.5 plus or minus 1.2 million years.

  13. [Anterior cruciate ligament-plasty using the "U-dos" technique].

    PubMed

    Morales-Trevizo, C; Paz-García, M; Leal-Berumen, I; Leal-Contreras, C; Berumen-Nafarrate, E

    2013-01-01

    The knee is a compound diarthrodial joint, vulnerable to serious injuries such as ligament injuries of: medial collateral ligament, lateral collateral ligament, anterior cruciate ligament and posterior cruciate ligament, as cruciate ligaments limit rotation movement in the joint. The purpose of our study was to create a new technique to treat injuries of the anterior cruciate ligament, which is composed of two bundles--anteromedial and posterolateral--trying to achieve an anatomical reconstruction that allows for a normal biomechanical recovery. This technique reduces the use of fixation material and costs. The diagnosis of anterior cruciate ligament injuries was made with the pivot shift test. There are currently two repair methods for anterior cruciate ligament injuries: single bundle or double bundle repair; none of these techniques is considered as the gold standard, as their results are very similar. This paper describes a technique used for the treatment of anterior cruciate ligament injuries, known as "U-dos", and its clinical results. Cross-sectional, observational study that enrolled 20 patients with total anterior cruciate ligament injuries who underwent anterior cruciate ligament plasty using the "U-dos" technique between June 2009 and June 2010. The technique requires the use of bone bank allograft, in this case of the anterior tibial ligament. Patients were assessed using the Lysholm scale and the pivot shift test. Our results show that all the pivot shift tests were negative and assessments according to the Lysholm scale were from normal to excellent in 95% of cases (19/20). Only one failure was reported, with avulsion of the graft attachment which required a surgical intervention.

  14. Perfusion and thallium single photon emission computed tomography in herpes simplex encephalitis.

    PubMed

    De Deyn, P P; Van den Broucke, P W; Pickut, B A; Appel, B; Crols, R; Cras, P; Martin, J J

    1998-04-15

    This is the first report on 201thallium-single photon emission computed tomography (201Tl-SPECT) brain scan of a patient with herpes simplex encephalitis (HSE). The presented 201Tl-SPECT observations are correlated with 99mtechnetium hexamethylpropylene amine oxime (99mTc-HMPAO) perfusion SPECT and magnetic resonance imaging (MRI) findings. Brain 99mTc-HMPAO perfusion SPECT reveals a hyperperfusion in the right temporal lobe with extension to the parietal lobe and a hypoperfusion in the ipsilateral occipital lobe. 201Tl-SPECT shows a fixation in the right temporal lobe coinciding with the gadolinium enhancement on MRI. The right occipital lesion shown by gadolinium captation on MRI and hypoperfusion on 99mTc-HMPAO perfusion SPECT was not evident on the 201Tl SPECT. These findings could illustrate that the lesions might be different pathophysiologically.

  15. Thallium-201 uptake in lung cancer

    SciTech Connect

    Chin, B.B.; Zukerberg, B.W.; Buchpiguel, C.; Alavi, A.

    1995-08-01

    {sup 201}Tl imaging and {sup 99m}Tc-sestamibi have shown a high sensitivity in detecting lung and breast malignancies. Recent studies with delayed imaging have reported acceptable specificity compared to earlier reports. Further prospective studies are necessary to determine the role of various imaging modalities, including PET and single gamma emitters such as {sup 201}Tl, {sup 99m}Tc-sestamibi and radiolabeled somatostatin receptor agents in the management of patients with various malignancies. 52 refs., 4 figs.

  16. 48 CFR 653.217-70 - DOS form DS-1921, Award/Modification of Interagency Acquisition Agreement.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 4 2010-10-01 2010-10-01 false DOS form DS-1921, Award...-1921, Award/Modification of Interagency Acquisition Agreement. As prescribed in 617.504-70(b)(5)(i), DS-1921 is prescribed for use when awarding or modifying Economy Act Interagency Acquisition...

  17. Quantitative analysis of planar technetium-99m-sestamibi myocardial perfusion images using modified background subtraction

    SciTech Connect

    Koster, K.; Wackers, F.J.; Mattera, J.A.; Fetterman, R.C. )

    1990-08-01

    Standard interpolative background subtraction, as used for thallium-201 ({sup 201}Tl), may create artifacts when applied to planar technetium-99m-Sestamibi ({sup 99m}Tc-Sestamibi) images, apparently because of the oversubtraction of relatively high extra-cardiac activity. A modified background subtraction algorithm was developed and compared to standard background subtraction in 16 patients who had both exercise-delayed {sup 201}Tl and exercise-rest {sup 99m}Tc-Sestamibi imaging. Furthermore, a new normal data base was generated. Normal {sup 99m}Tc-Sestamibi distribution was slightly different compared to {sup 201}Tl. Using standard background subtraction, mean defect reversibility was significantly underestimated by {sup 99m}Tc-Sestamibi compared to {sup 201}Tl (2.8 +/- 4.9 versus -1.8 +/- 8.4, p less than 0.05). Using the modified background subtraction, mean defect reversibility on {sup 201}Tl and {sup 99m}Tc-Sestamibi images was comparable (2.8 +/- 4.9 versus 1.7 +/- 5.2, p = NS). We conclude, that for quantification of {sup 99m}Tc-Sestamibi images a new normal data base, as well as a modification of the interpolative background subtraction method should be employed to obtain quantitative results comparable to those with {sup 201}Tl.

  18. Thallium-201 kinetics in nonischemic canine myocardium

    SciTech Connect

    Okada, R.D.; Jacobs, M.L.; Daggett, W.M.

    1982-01-01

    Myocardial thallium-201 (/sup 201/Tl) kinetics have not been precisely defined because reliable techniques to determine continuous activity in vivo have not been available. In this study, an implantable miniature cadmium telluride radiation detection device was inserted through the left ventricular apex, positioned against the endocardium, and used for continuous on-line monitoring of myocardial /sup 201/Tl activity for 260-810 minutes in 18 dogs. Blood was serially sampled and counted. Microsphere-determined myocardial blood flow was measured before administration of /sup 201/Tl and was not significantly different from that measured at the end of the experiment in 11 of 18 dogs. Thallium was administered intravenously. Myocardial and blood activity curves were analyzed using a nonlinear least-squares estimation of the decay constant lambda (min/sup -1/). The mean final blood lambda/sub 3/ was almost identical to the mean myocardial lambda. The data suggest that /sup 201/Tl washout after peak activity is reached in nonischemic myocardium is mono-exponential. The rate of /sup 201/Tl clearance from the myocardium is related to the rate of /sup 201/Tl clearance from the blood after i.v. administration of the tracer.

  19. Endocrine disruptors in water filters used in the Rio dos Sinos Basin region, Southern Brazil.

    PubMed

    Furtado, C M; von Mühlen, C

    2015-05-01

    The activated carbon filter is used in residences as another step in the treatment of drinking water, based on a physical-chemical process to absorb pollutants that are not removed in conventional treatment. Endocrine disruptors (EDCs) are exogenous substances or mixtures of substances that acts on the endocrine system similarly to the endogenously produced hormones, triggering malfunctions and harmful changes to human and animal health. The objective of the present work was to study EDCs through semi-quantitative analysis of residential water filters collected in the region of Rio dos Sinos basin, focusing on two specific classes: hormones and phenols. The solid phase extraction principle was used for the extraction of compounds and gas chromatography coupled with mass spectrometry for the separation and characterization of EDCs. Four samples of residential filters collected from public water distribution and artesian wells, from the cities of Novo Hamburgo and São Leopoldo were analysed. Using the developed methodology, it was possible to detect and comparatively quantify selected EDCs in all studied samples, which indicates the presence of these contaminants in drinking water from different sources. PMID:26270219

  20. Environmental discrimination among soft-bottom mollusc associations off Lagoa dos Patos, South Brazil

    NASA Astrophysics Data System (ADS)

    Absalão, R. S.

    1991-01-01

    Sublittoral benthic molluscs established in the outlet of Lagoa dos Patos (South Brazil) were sampled with a rectangular dredge and the malacological associations delineated by cluster analysis (WPGA) using the Baroni-Urbani and Buser similarity index. Three main associations were characterized in bands parallel to the beach with relative concordance with specific sedimentological facies. The multiple discriminant analysis showed that there was a high correlation between these associations and the following environmental parameters: depth, average grain size, skewness of the sediment, medium sand, coarse sand, total sand and total mud. The effect of reducing the multidimensionality of the data to two factors, ecologically explained, brings out the importance of depth, average grain size, total sand and total mud. The first appears to be a bathymetric gradient of stability/disturbance; the disturbance from storms becomes less frequent with increasing depth. This is partially supported by the results of the Caswell neutral model, and is in agreement with the intermediate disturbance hypothesis predictions. The second sedimentological factor is the relative percentages of sand and mud in determining the specific composition of these associations.

  1. Geochemical and isotopic constraints on the tectonic setting of Serra dos Carajas belt, eastern Para, Brazil

    NASA Technical Reports Server (NTRS)

    Olszewski, W. J., Jr.; Gibbs, A. K.; Wirth, K. R.

    1986-01-01

    The lower part of the Serra dos Carajas belt is the metavolcanic and metasedimentary Grao para Group (GPG). The GPG is thought to unconformably overlie the older (but undated) Xingu Complex, composed of medium and high-grade gneisses and amphibolite and greenstone belts. The geochemical data indicate that the GPG has many features in common with ancient and modern volcanic suites erupted through continental crust. The mafic rocks clearly differ from those of most Archean greenstone belts, and modern MORB, IAB, and hot-spot basalts. The geological, geochemical, and isotopic data are all consistent with deposition on continental crust, presumably in a marine basin formed by crustal extension. The isotopic data also suggest the existence of depleted mantle as a source for the parent magmas of the GPG. The overall results suggest a tectonic environment, igneous sources, and petrogenesis similar to many modern continental extensional basins, in contrast to most Archean greenstone belts. The Hammersley basin in Australia and the circum-Superior belts in Canada may be suitable Archean and Proterozoic analogues, respectively.

  2. Geophysical maps of the Dos Cabezas Mountains Wilderness Study Area, Cochise County, Arizona

    USGS Publications Warehouse

    Abrams, G.A.

    1986-01-01

    In the Dos Cabezas Mountains the Apache Pass fault zone is the major structural feature, barely skirting the southwest side of the study area. It extends several miles to the northwest and tens of miles to the southeast, across the Chiricahua Mountains beyond Apache Pass. It is typically made up of a pair of bounding faults and some anastomosing faults between them. The study area is underlain by a variety of sedimentary, igneous, and metamorphic rocks that provide only a fragmentary record of geologic events between Precambrian and Holocene times. A suite of metamorphic and igneous (primarily crystalline) rocks forms the basement terrain. Paleozoic and Mesozoic sedimentary rocks and also Paleozoic and Mesozoic volcanic rocks overlie the basement rocks but are extensively eroded away and may be covered. A pile of volcanic rocks of Late Cretaceous and Paleocene age caps the older rocks in much of the study area. Mid-Tertiary intrusive rocks underlie the eastern part of the study area as well as some very small, widely scattered additional localities. Quaternary gravel deposits occur in the major valleys and along the mountain front.

  3. Hydra: a C-language environment for real-time DOS multitasking at the bedside.

    PubMed

    DeGaetano, A; Coleman, W P; Pizzi, R; Tomasella, E; Castagneto, M; Greco, A V

    1993-10-01

    Patient monitoring at the bedside is an inherently parallel job, best handled by multiple individual tasks running concurrently. Cost and diffusion considerations strongly favor the use of PC's at the bedside, but their most widespread operating system, DOS, is not built for multitasking. Hence, a software platform in C language has been prepared, allowing the intermediate programmer to easily write independent modules which will then run simultaneously without conflicts. Such a platform aims at allowing effortless sharing of data among concurrently running processes, while providing strong insulation between tasks, enough to allow multiple copies of any one task to run simultaneously unknown to each other. A cooperative, memory sharing multitasking paradigm has been chosen, which offers fine granularity of timeslicing and low execution overhead at the price of some loss in generality of design. Speed, data exchange capability and number of stackable windows are greater than with commercial packages like Windows or LabWindows. Dynamical reprioritization of tasks is built in, allowing the computerized monitor to focus its attention and resources on urgent tasks.

  4. Endocrine disruptors in water filters used in the Rio dos Sinos Basin region, Southern Brazil.

    PubMed

    Furtado, C M; von Mühlen, C

    2015-05-01

    The activated carbon filter is used in residences as another step in the treatment of drinking water, based on a physical-chemical process to absorb pollutants that are not removed in conventional treatment. Endocrine disruptors (EDCs) are exogenous substances or mixtures of substances that acts on the endocrine system similarly to the endogenously produced hormones, triggering malfunctions and harmful changes to human and animal health. The objective of the present work was to study EDCs through semi-quantitative analysis of residential water filters collected in the region of Rio dos Sinos basin, focusing on two specific classes: hormones and phenols. The solid phase extraction principle was used for the extraction of compounds and gas chromatography coupled with mass spectrometry for the separation and characterization of EDCs. Four samples of residential filters collected from public water distribution and artesian wells, from the cities of Novo Hamburgo and São Leopoldo were analysed. Using the developed methodology, it was possible to detect and comparatively quantify selected EDCs in all studied samples, which indicates the presence of these contaminants in drinking water from different sources.

  5. Urano y sus dos satélites irregulares recientemente descubiertos

    NASA Astrophysics Data System (ADS)

    Parisi, M. G.; Brunini, A.

    Hasta hace poco tiempo, Urano era el único de los Planetas Gigantes que no poseía satélites irregulares. Esto lo diferenciaba del resto de los planetas Gigantes, al igual que la peculiar oblicuidad de su eje de spin. La gran inclinación de su eje de rotación se debe probablemente a una colisión que sufrió el planeta con otro embrión planetario al final del proceso de formación. Esta colisión habría desligado satélites exteriores preexistentes del planeta. Recientemente se han descubierto dos satélites irregulares de Urano, lo que introduce algunas nuevas cotas y condiciones en el escenario de la "Hipótesis de la Gran Colisión" . Los satélites irregulares de Urano tuvieron que ser capturados en una etapa posterior a la del escenario de la Gran Colisión, de no ser así, hubieran sido eyectados del sistema por el impulso impartido con ese gran impacto. En este trabajo, se discuten los posibles mecanismos de captura de los satélites irregulares y se presenta un nuevo posible mecanismo para dicha captura.

  6. Creating a Global Fiducials Program (GFP) Site: Lago Cachet Dos example in Chile

    NASA Astrophysics Data System (ADS)

    Friesen, B. A.; Nimick, D. A.; Wilson, E. M.

    2012-12-01

    The USGS has been acquiring remotely sensed imagery from all over the world, collecting thousands of images at more than 200 sites, and creating Literal Image Derived Products (LIDPs) as part of the Global Fiducials Program (GFP). The GFP program enables scientists to use these images to study our rapidly changing planet at carefully selected locations around the world. New GFP Sites are created and added each year. Researchers at the University of Alaska, for instance, added areas susceptible to coastal erosion for monitoring the long-term effects of high tides and storms. This presentation will guide you through the process of creating a new GFP site for your area of interest. We will describe the components of the GFP and its archive, the Global Fiducials Library. The Global Fiducials Program—Initial Site Proposal form will be presented and we will show you how to complete each component in order to propose a new site. Lago Cachet Dos, a glacier-dammed lake in southern Chile, is currently being proposed as a new GFP site and will be used as the example for this exercise. In addition, USGS web sites will be used to illustrate how a long-term imagery record can tell a story and to demonstrate viewing and downloading the type of data that will be available online and free of charge through the GFP.

  7. Open Cluster Radial Velocity determination from observations at Observatório Pico Dos Dias

    NASA Astrophysics Data System (ADS)

    Faria, M. A. F.; Monteiro, H.; Dias, W. S.; Lépine, J. R. D.

    2014-10-01

    In studies of the dynamics of the Galactic disk, such as the determination of the speed of the spiral pattern and the permanence of stars in the spiral arms, it is crucial to know orbits obtained from proper motions, radial velocities and the potential of the Galaxy. Aiming to improve the statistics of our catalog of open clusters, maintained by our research group, we determined the radial velocity of stars belonging to a group of open clusters using spectra with a resolution of 4000, obtained at the Pico dos Dias Observatory (LNA) with the 1.60 m telescope and the Coudé spectrograph. We observed the open cluster's member stars and calculated their radial speeds using standard techniques. The stars were selected from our own database based on relevant information concerning the clusters, obtained by statistical analysis of their proper motions and/or their position in the HR's diagram. In this work, we present the detailed analysis of the data reduction and radial velocity determination using synthetic spectra from different libraries. Finally we present the open cluster's radial (and spacial) velocities.

  8. 32 CFR Appendix C to Part 197 - Procedures for the Department of State (DoS) Foreign Relations of the United States (FRUS) Series

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) Foreign Relations of the United States (FRUS) Series C Appendix C to Part 197 National Defense Department... 197—Procedures for the Department of State (DoS) Foreign Relations of the United States (FRUS) Series... the DoS for the FRUS series under Public Law No. 102-138. b. Request authorization from the CIA,...

  9. Lessons Learned from Sleep Education in Schools: A Review of Dos and Don'ts

    PubMed Central

    Blunden, Sarah; Rigney, Gabrielle

    2015-01-01

    Study Objectives: Sleep duration and quality are associated with negative neuropsychological and psychosocial outcomes in children and adolescents. However, community awareness of this is low and sleep education programs in schools are attempting to address this issue. Several studies now exist assessing the efficacy of these sleep education programs for improving sleep knowledge, sleep hygiene and sleep patterns. This paper presents these sleep education programs, most particularly, it presents the strengths and weaknesses of the current available studies in the hope that this can identify areas where future sleep education programs can improve. Methods: A systematic search of all school-based sleep education studies in adolescents was undertaken. Studies were scrutinized for author, teacher and participant comment regarding strengths and limitations of each study, which were then extracted and summarized. Results: Two specific types of sleep education programs emerged from the review, those that sought to change sleep behavior and those that sought simply to disseminate information. Issues that dictated the strength or weakness of a particular study including who delivers the program, the theoretical basis, the tools utilized to measure sleep patterns, the content, and their capacity to engage students were assessed. Sleep education was considered important by teachers, students and parents alike. Conclusions: Future sleep education programs need to take into account lessons learned from previous sleep education efforts in order to maximize the potential for sleep education programs to improve the sleep health of our young people. Commentary: A commentary on this article appears in this issue on page 595. Citation: Blunden S, Rigney G. Lessons learned from sleep education in schools: a review of dos and don'ts. J Clin Sleep Med 2015;11(6):671–680. PMID:25766709

  10. The Relationship between Older Drivers’ Performance on the Driving Observation Schedule (eDOS) and Cognitive Performance

    PubMed Central

    Koppel, Sjaan; Charlton, Judith; Langford, Jim; Vlahodimitrakou, Zafiroula; Di Stefano, Marilyn; Macdonald, Wendy; Mazer, Barbara; Gelinas, Isabelle; Vrkljan, Brenda; Marshall, Shawn

    2013-01-01

    Research question/Objective: The Driving Observation Schedule (eDOS) was developed for use in the Candrive/Ozcandrive five-year prospective study of older drivers to observe the driving behavior of older drivers and monitor changes in driving behaviors over time. The aim of this study is to describe participants’ driving performance during the eDOS driving task and investigate the association between driving performance and cognitive measures. Methods: A subset of Ozcandrive participants (n = 144, 104 male [72%], 40 female [28%], Mean age = 81.49 years, SD = 3.58 years, Range: 76 – 96 years) completed the eDOS driving task. Participants drove to their selected destinations (up to 4 locations), with observations of driving behaviors (both inappropriate and appropriate) recorded for specific driving maneuvers: intersection negotiation, lane-changing, merging, low speed maneuvers and maneuver-free driving. Driving behaviors (e.g. signalling, speed regulation, gap acceptance, lane position, ‘critical errors’) were scored by a trained observer and participants received an overall eDOS driving task score (Maximum = 100 points). Participants also completed a series of cognitive assessments as part of the Year 2 Candrive/Ozcandrive assessment protocols. Results: The overall eDOS driving task score was very high (M = 95.77; SD = 5.15; Range = 65.63 – 100). Detailed analyses of participants’ driving behavior revealed a high level of appropriate driving behavior (96%, n = 5,935 maneuvers), with few errors (4%, n = 252 maneuvers). While most participants’ performance on the cognitive assessments was high, some scores were below the criteria for cogntive impairment (BIC) according to conventional benchmarks: (MoCA: M = 26.56, SD = 2.12, Range = 19 – 30, % BIC = 28%; MMSE: M = 29.10, SD = 1.01, Range = 26–30, %BIC = 0%; Trails B: M = 111.66, SD = 43.53, Range = 50 – 301, %BIC = 6%). There was no significant relationship observed between participants

  11. Video movie making using remote procedure calls and 4BSD Unix sockets on Unix, UNICOS, and MS-DOS systems

    SciTech Connect

    Robertson, D.W.; Johnston, W.E.; Hall, D.E.; Rosenblum, M.

    1990-03-01

    We describe the use of the Sun Remote Procedure Call and Unix socket interprocess communication mechanisms to provide the network transport for a distributed, client-server based, image handling system. Clients run under Unix or UNICOS and servers run under Unix or MS-DOS. The use of remote procedure calls across local or wide-area networks to make video movies is addressed.

  12. Investigation of the relationship between protein-protein interaction and catalytic activity of a heme-regulated phosphodiesterase from Escherichia coli (Ec DOS) by protein microarray.

    PubMed

    Sasakura, Yukie; Kanda, Katsuhiro; Yoshimura-Suzuki, Tokiko; Matsui, Takuya; Fukuzono, Shinichi; Shimizu, Toru

    2005-07-19

    Ec DOS, a heme-regulated phosphodiesterase from Escherichia coli, is composed of an N-terminal heme-bound PAS domain and a C-terminal phosphodiesterase domain. The heme redox state in the PAS domain regulates Ec DOS phosphodiesterase activity. Interestingly, the isolated heme-bound PAS fragment enhances phosphodiesterase activity of full-length Ec DOS. The enhancement is also regulated by the heme redox state of the isolated PAS domain. In the present study, we used a newly developed protein microarray system to examine the relationship between catalytic activity and the interaction of full-length Ec DOS and the isolated PAS fragment. Adenosine 3',5'-cyclic monophosphate (cAMP), a substrate of the Ec DOS phosphodiesterase, was found to be indispensable for the interaction between Ec DOS and the PAS fragment, and two phosphodiesterase inhibitors, 3-isobutyl-methyl-xanthine and etazolate hydrochloride, hindered the interaction. In addition, an enzyme with a mutation in the putative cAMP-binding sites (H590 and H594) was unable to interact with Ec DOS and lacked enzymatic activity. These results strongly suggest a close relationship between Ec DOS phosphodiesterase activity and interaction with the isolated PAS fragment. Therefore, this study provides insights into the mechanism of how the isolated PAS domain activates Ec DOS, which has important implications for the general role of the isolated PAS domain in cells. Moreover, we found that multiple microscale analyses using the protein microarray system had several advantages over conventional affinity column methods, including the quantity of protein needed, the sensitivity, the variability of immobilized protein, and the time required for the experiment. PMID:16008345

  13. Research on a Denial of Service (DoS) Detection System Based on Global Interdependent Behaviors in a Sensor Network Environment

    PubMed Central

    Song, Jae-gu; Jung, Sungmo; Kim, Jong Hyun; Seo, Dong Il; Kim, Seoksoo

    2010-01-01

    This research suggests a Denial of Service (DoS) detection method based on the collection of interdependent behavior data in a sensor network environment. In order to collect the interdependent behavior data, we use a base station to analyze traffic and behaviors among nodes and introduce methods of detecting changes in the environment with precursor symptoms. The study presents a DoS Detection System based on Global Interdependent Behaviors and shows the result of detecting a sensor carrying out DoS attacks through the test-bed. PMID:22163475

  14. Análise dos Conceitos Astronômicos Apresentados por Professores de Algumas Escolas Estaduais Brasileiras

    NASA Astrophysics Data System (ADS)

    Voelzke, Marcos Rincon; Gonzaga, Edson Pereira

    2011-12-01

    A razão para o desenvolvimento deste trabalho baseia-se no fato de que muitos professores da Educação Básica (EB) não lidam com conceitos relacionados à astronomia, e quando o fazem eles simplesmente seguem livros didáticos que podem conter erros conceituais. Como é de conhecimento geral a astronomia é um dos conteúdos a serem ensinados na EB fazendo parte dos Parâmetros Curriculares Nacionais e das Propostas Curriculares do Estado de São Paulo, mas é um fato, que vários pesquisadores apontam, a existência de muitos problemas no ensino da astronomia. Com o propósito de minimizar algumas dessas deficiências foi realizado um trabalho de pesquisa com a utilização de questionários pré e pós pesquisa, para tanto foi desenvolvido um Curso de Extensão Universitária para professores da Diretoria de Ensino Regional (DE) que abrange Mauá, Ribeirão Pires e Rio Grande da Serra (no Estado de São Paulo) com os seguintes objetivos: levantar concepções alternativas; subsidiar os professores por meio de palestras, debates e workshops, e verificar o sucesso da aprendizagem após o curso, adotando-se como referência, para a análise dos resultados, os dicionários de Língua Portuguesa (FERREIRA, 2004) e Enciclopédico de Astronomia e Astronáutica (MOURĀO, 1995). Portanto, dezesseis questões foram aplicadas antes e após o curso, assim pode-se verificar após a pesquisa que 100,0% dos professores sabiam os nomes das fases da Lua, 97,0% entenderam que o Sistema Solar é composto por oito planetas, 78,1% foram capazes de explicar como ocorre um eclipse lunar, um eclipse solar e um solstício, 72,7% sabiam como explicar a ocorrência das estações do ano; 64,5% explicaram corretamente a ocorrência do equinócio, 89,7% foram capazes de definir adequadamente o termo cometa; 63,6% definiram asteróide, 54,5% meteoro, 58,1% galáxia, e 42,4% planeta. Os resultados obtidos indicam uma aprendizagem significativa por parte dos participantes.

  15. 32 CFR Appendix C to Part 197 - Procedures for the Department of State (DoS) Foreign Relations of the United States (FRUS) Series

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... the DoS for the FRUS series under Public Law No. 102-138. b. Request authorization from the CIA, NSC.... Submit to the respective Agency a list of CIA and NSC documents copied and released to the...

  16. 32 CFR Appendix C to Part 197 - Procedures for the Department of State (DoS) Foreign Relations of the United States (FRUS) Series

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... the DoS for the FRUS series under Public Law No. 102-138. b. Request authorization from the CIA, NSC.... Submit to the respective Agency a list of CIA and NSC documents copied and released to the...

  17. 32 CFR Appendix C to Part 197 - Procedures for the Department of State (DoS) Foreign Relations of the United States (FRUS) Series

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... the DoS for the FRUS series under Public Law No. 102-138. b. Request authorization from the CIA, NSC.... Submit to the respective Agency a list of CIA and NSC documents copied and released to the...

  18. Rare earth elements in Angra dos Reis and Lewis Cliff 86010, two meteorites with similar but distinct magma evolutions

    NASA Technical Reports Server (NTRS)

    Crozaz, Ghislaine; Mckay, Gordon

    1990-01-01

    Data are presented on ion microprobe measurements of REE and selected trace element abundances in individual grains of merrillite, fassaite, olivine, kirschsteinite, and plagioclase of Lewis Cliff 86010 (LEW 86010) meteorite and in merrillite and fassaite grains of Angra dos Reis (ADOR). Results show a close relationship between the two meteorites and support a magmatic origin for LEW 86010. However, the measurements indicate that, despite numerous common characteristics, the two meteorites must have been produced in separate magmatic events involving similar but distinct processes and parent melts.

  19. Kinetic analysis of 18F-fluorodihydrorotenone as a deposited myocardial flow tracer: Comparison to thallium-201.

    SciTech Connect

    Marshall, Robert C.; Powers-Risius, Patricia; Reutter, Bryan W.; O'Neil, James P.; La Belle, Michael; Huesman, Ronald H.; VanBrocklin, Henry F.

    2004-03-01

    The goal of this investigation was to assess the accuracy of 18F-fluorodihydrorotenone (18F-FDHR) as a new deposited myocardial flow tracer and compare the results to those for 201Tl. Methods. The kinetics of these flow tracers were evaluated in 22 isolated, erythrocyte- and albumin-perfused rabbit hearts over a flow range encountered in patients. The two flow tracers plus a vascular reference tracer (131I-albumin) were introduced as a bolus through a port just above the aortic cannula. Myocardial extraction, retention, washout, and uptake parameters were computed from the venous outflow curves using the multiple indicator dilution technique and spectral analysis. Results. The mean initial extraction fractions of 18F-FDHR (0.85 +- 0.07) and 201Tl (0.87 +- 0.05) were not significantly different, although the initial extraction fraction for 18F-FDHR declined with flow (P < 0.0001), whereas the initial extraction fraction of 201Tl did not. Washout of 201Tl was faster (P < 0.001) and more affected by flow (P < 0.05) than 18F-FDHR washout. Except for initial extraction fraction, 18F-FDHR retention was greater (P < 0.001) and less affected by flow (P < 0.05) than 201Tl retention. Reflecting its superior retention, net uptake of 18F-FDHR was better correlated with flow than 201Tl uptake at both one and fifteen minutes after tracer introduction (P < 0.0001 for both comparisons). Conclusion. The superior correlation of 18F-FDHR uptake with flow indicates that it is a better flow tracer than 201Tl in the isolated rabbit heart. Compared to the other currently available positron-emitting flow tracers (82Rb, 13N-ammonia, and 15O-water), 18F-FDHR has the potential of providing excellent image resolution without the need for an on-site cyclotron.

  20. Perfil de temperatura dos funis magnetosféricos de estrelas T Tauri com aquecimento alfvênico

    NASA Astrophysics Data System (ADS)

    Vasconcelos, M. J.

    2003-08-01

    Estrelas T Tauri Clássicas são objetos jovens circundados por discos de gás e poeira e que apresentam uma intensa atividade magnética. Seu espectro mostra linhas de emissão alargadas que são razoavelmente reproduzidas nos modelos de acresção magnetosférica. No entanto, o perfil de temperatura dos funis magnéticos é desconhecido. Aquecimento magnético compressional e difusão ambipolar foram considerados para estas estruturas, porém as temperaturas obtidas não são suficientes para explicar as observações. Neste trabalho, examinamos o aquecimento gerado pelo amortecimento de ondas Alfvén através de quatro mecanismos, os amortecimentos não-linear, turbulento, viscoso-resistivo e colisional como função da freqüência da onda. Inicialmente, a temperatura é ajustada para reproduzir as observações e o grau de turbulência requerido para que o mecanismo seja viável é calculado. Os resultados mostram que este é compatível com os dados observacionais. Apresentam-se, também, resultados preliminares do cálculo auto-consistente do perfil de temperatura dos funis, levando-se em conta fontes de aquecimento Alfvênica e fontes de resfriamento.

  1. Degradability of dimethyl terephthalate by Variovorax paradoxus T4 and Sphingomonas yanoikuyae DOS01 isolated from deep-ocean sediments.

    PubMed

    Wang, Yu Ping; Gu, Ji-Dong

    2006-08-01

    Two strains of bacteria were isolated from deep-ocean sediments of the South China Sea using enrichment culturing technique and they were identified as Sphingomonas yanoikuyae DOS01 (AY878409) and Variovorax paradoxus T4 (AY878410) based on 16S rRNA gene sequences. S. yanoikuyae DOS01 was only capable of transforming dimethyl terephthalate (DMTP) to monomethyl terephthalate (MMTP) without further degradation while V. paradoxus T4 exhibited ability in mineralizing DMTP as the sole source of carbon and energy. The biochemical pathway of DMTP degradation was through MMTP and terephthalic acid (TA) as major detectable degradation intermediates in the culture media by both microorganisms. V. paradoxus T4 utilized DMTP and MMTP via hydrolysis of diester and monoester in the initial steps in degradation as confirmed by total organic carbon analysis of the culture medium and esterase activity assay of the lysed cells and fraction. The specific hydrolysis activity of esterase induced by DMTP or MMTP showed that greater hydrolysis of p-nitrophenyl acetate by esterase induced by DMTP-grown cells than that induced by MMTP. Results of this research suggest that the cleavage of the two identical carboxylic ester groups of phthalate diester are carried out by highly specific esterases of the same bacteria in the environment.

  2. Contextual variation in young children’s observed disruptive behavior on the DB-DOS: implications for early identification

    PubMed Central

    Petitclerc, Amélie; Briggs-Gowan, Margaret J.; Estabrook, Ryne; Burns, James L.; Anderson, Erica L.; McCarthy, Kimberly J.; Wakschlag, Lauren S.

    2015-01-01

    Background Contextual variation in child disruptive behavior is well documented but remains poorly understood. We first examine how variation in observed disruptive behavior across interactional contexts is associated with maternal reports of contextual variation in oppositional-defiant behavior and functional impairment. Second, we test whether child inhibitory control explains the magnitude of contextual variation in observed disruptive behavior. Methods Participants are 497 young children (mean age = 4 years, 11 months) from a subsample of the MAPS, a sociodemographically diverse pediatric sample, enriched for risk of disruptive behavior. Observed anger modulation and behavioral regulation problems were coded on the Disruptive Behavior Diagnostic Observation Schedule (DB-DOS) during interactions with parent and examiner. Oppositional-defiant behavior, and impairment in relationships, with parents and nonparental adults, were measured with the Preschool Age Psychiatric Assessment (PAPA) interview with the mother. Functional impairment in the home and out-and-about was assessed with the Family Life Impairment Scale (FLIS), and expulsion from child care/school was measured with the baseline survey and FLIS. Results Observed disruptive behavior on the DB-DOS Parent Context was associated with oppositional-defiant behavior with parents, and with impairment at home and out-and-about. Observed disruptive behavior with the Examiner was associated with oppositional-defiant behavior with both parents and nonparental adults, impairment in relationships with nonparental adults, and child care/school expulsion. Differences in observed disruptive behavior in the Parent versus Examiner Contexts was related to the differences in maternal reports of oppositional-defiant behavior with parents versus nonparental adults. Children with larger decreases in disruptive behavior from Parent to Examiner Context had better inhibitory control and fewer attention

  3. [The Arabic influence in the "Colóquios dos simples e drogas da India" of Garcia da Orta].

    PubMed

    Ricordel, Joëlle

    2015-09-01

    The "Colóquios dos simples e drogas he cousas medicinais de Índia" (Conversations on the simples, drugs and medicinal substances of India) (1563) of Garcia da Orta is a botanical and pharmacognosy book. The author is a Portuguese physician who studied in the Spanish universities and practiced medicine mainly in India. He studies in short chapters presented in the form of dialogues about sixty simples. Sources to which he refers are indicative of a "classical" training, but also the mark of a curious and open mind to different cultures. The Arabic sources are numerous and mainly concern the identification of substances by abundant synonyms of their names in foreign languages and different medicinal uses that may have been done by the ancient physicians. However, Da Orta is critical with respect to these sources, seeking contradictions and differences of opinion among authors. He confronts them with the oral information collected thanks to a wide network of contacts. PMID:26529894

  4. [The Arabic influence in the "Colóquios dos simples e drogas da India" of Garcia da Orta].

    PubMed

    Ricordel, Joëlle

    2015-09-01

    The "Colóquios dos simples e drogas he cousas medicinais de Índia" (Conversations on the simples, drugs and medicinal substances of India) (1563) of Garcia da Orta is a botanical and pharmacognosy book. The author is a Portuguese physician who studied in the Spanish universities and practiced medicine mainly in India. He studies in short chapters presented in the form of dialogues about sixty simples. Sources to which he refers are indicative of a "classical" training, but also the mark of a curious and open mind to different cultures. The Arabic sources are numerous and mainly concern the identification of substances by abundant synonyms of their names in foreign languages and different medicinal uses that may have been done by the ancient physicians. However, Da Orta is critical with respect to these sources, seeking contradictions and differences of opinion among authors. He confronts them with the oral information collected thanks to a wide network of contacts.

  5. Another new and threatened species of lancehead genus Bothrops (Serpentes, Viperidae) from Ilha dos Franceses, Southeastern Brazil.

    PubMed

    Barbo, Fausto E; Gasparini, João Luiz; Almeida, Antonio P; Zaher, Hussam; Grazziotin, Felipe G; Gusmão, Rodrigo B; Ferrarini, José Mário G; Sawaya, Ricardo J

    2016-01-01

    A new insular species of the genus Bothrops is described from Ilha dos Franceses, a small island off the coast of Espírito Santo State, in southeastern Brazil. The new species differs from mainland populations of B. jararaca mainly by its small size, relative longer tail, relative smaller head length, and relative larger eyes. The new species is distinguished from B. alcatraz, B. insularis and B. otavioi by the higher number of ventral and subcaudal scales, relative longer tail and smaller head. The new species is highly abundant on the island, being nocturnal, semiarboreal, and feeding on small lizards and centipeds. Due its unique and restricted area of occurrence, declining quality of habitat, and constant use of the island for tourism, the new species may be considered as critically endangered. PMID:27394563

  6. NGC 2287: Un cúmulo abierto rico en binarias espectroscópicas de dos espectros

    NASA Astrophysics Data System (ADS)

    Levato, H.; Malaroda, S.; García, B.; Grosso, M.

    NGC 2287 contiene 100 estrellas con buena fotometría y 40 con tipos MK. En 1979 Levato et al., usando la técnica de la clasificación espectral, descubrieron que la mayoría de las estrellas en el rango B8-A0 eran binarias espectroscópicas con una inusual proporción de binarias con dos espectros. El presente proyecto tuvo el propósito de confirmar la naturaleza binaria de los miembros del cúmulo. Hemos obtenido espectros con resolución 14000 de 15 estrellas clasificadas como binarias. Los espectros, que abarcan la región λ 3500-λ 6000 Å, permitieron confirmar la naturaleza binaria de varias de las estrellas en la muestra. Hacemos notar el considerable interés astrofísico de este cúmulo abierto.

  7. Application of geostatistical methods to arsenic data from soil samples of the Cova dos Mouros mine (Vila Verde-Portugal).

    PubMed

    Reis, A P; Sousa, A J; Da Silva, E Ferreira; Fonseca, E Cardoso

    2005-09-01

    A total of 286 soil samples were collected in the Cova dos Mouros area. All samples were dry sieved into the <200 mesh size fraction and analysed for Fe, Cu, Zn, Pb, Co, Ni, Bi and Mn by atomic absorption spectrometry (AAS) and for As, Se, Sb and Te by atomic absorption spectrometry-hydrid generation (AAS-HG). Only the results of arsenic are discussed in this paper although the survey was extended to all analysed chemical elements. The purpose of this study was to make a risk probability mapping for arsenic that would allow better knowledge about the vulnerability of the soil to arsenic contamination. To achieve this purpose, the initial variable was transformed into an indicator variable using as thresholds the risk-based standards (intervention values) for soils, as proposed by [Swartjes 1999. Risk based assessment of soil and groundwater quality in the Netherlands: Standards and remediation. J. Geochem. Explor.73 1-10]. To account for spatial structure, sample variograms were computed for the main directions of the sampling grid and a spherical model was fitted to each sample variogram (arsenic variable and indicator variables). The parameters of the spherical model fitted to the arsenic variable were used to predict arsenic concentrations at unsampled locations. A risk probability mapping was also done to assess the vulnerability of the soil towards the mining works. The parameters of the spherical model fitted to each indicator variable were used to estimate probabilities of exceeding the corresponding threshold. The use of indicator kriging as an alternative to ordinary kriging for the soil data of Cova dos Mouros produced unbiased probability maps that allowed assessment of the quality of the soil.

  8. Dual tracer autoradiographic study with thallium-201 and radioiodinated fatty acid in cardiomyopathic hamsters

    SciTech Connect

    Kurata, C.; Kobayashi, A.; Yamazaki, N.

    1989-01-01

    To investigate the usefulness of myocardial scintigraphy with radioiodinated 15-(p-iodophenyl)-3-R,S-methylpentadecanoic acid (BMIPP) in cardiomyopathy, quantitative dual tracer autoradiographic study with /sup 201/Tl and (/sup 125/I)BMIPP was performed in 27 cardiomyopathic Bio 14.6 Syrian hamsters and eight normal hamsters. Furthermore, 16 Bio 14.6 Syrian hamsters aged 21 days were divided into verapamil-treated (during 70 days) and control groups (respectively, n = 8), and autoradiography with /sup 201/Tl and (/sup 125/I)BMIPP was performed. Quantitative autoradiography demonstrated an uncoupling of /sup 201/Tl and (/sup 125/I)BMIPP distributions and a regional heterogeneity of (/sup 125/I)BMIPP distribution in cardiomyopathic hamsters aged more than 2 mo, while normal hamsters showed only mild heterogeneity of (/sup 125/I)BMIPP distribution without an uncoupling of tracers. Age-matched comparison between normal and cardiomyopathic hamsters (5-8 mo old) demonstrated that a difference between their (/sup 125/I)BMIPP distributions are more marked than that between their /sup 201/Tl distributions. Furthermore, (/sup 125/I)BMIPP visualized effects of verapamil on cardiomyopathy more distinctly than did /sup 201/Tl. In conclusion, myocardial imaging with (/sup 123/I)BMIPP could be useful for investigating cardiomyopathy and evaluating the efficacy of therapeutic intervention in patients with cardiomyopathy.

  9. Myocardial uptake of thallium and rubidium during alterations in perfusion and oxygenation in isolated rabbit hearts

    SciTech Connect

    Leppo, J.A.

    1987-05-01

    The comparative effects of altered cellular function and coronary perfusion on myocardial /sup 201/Tl and /sup 83/Rb uptake were evaluated in three groups of isolated rabbit hearts having isovolumic contractions. Paired-indication dilution experiments were performed with /sup 201/Tl, /sup 83/Rb, and /sup 111/In-labeled albumin as an intravascular reference marker. In Group A hearts (n = 12), isotope transport was determined during control, hypoxia, and ischemia. In Group B hearts (n = 8), isotope transport was measured at control flow and again at a 50% and 80% reduction. In Group C hearts (n = 8) only /sup 201/Tl uptake was determined at control and following coronary reperfusion. Myocardial /sup 201/Tl and /sup 83/Rb transport were not significantly different and were proportional to flow. Although all interventions caused significant hemodynamic alterations, neither tracer was affected by hypoxia at constant flow. Thallium-201 permeation, however, was transiently decreased immediately after coronary reperfusion. We conclude that myocardial uptake of /sup 201/Tl and /sup 83/Rb are similar and directly related to flow, but do not reflect hypoxia induced cellular dysfunction.

  10. Detection of cardiomyopathy in an animal model using quantitative autoradiography

    SciTech Connect

    Kubota, K.; Som, P.; Oster, Z.H.; Brill, A.B.; Goodman, M.M.; Knapp, F.F. Jr.; Atkins, H.L.; Sole, M.J.

    1988-10-01

    A fatty acid analog (15-p-iodophenyl)-3,3 dimethyl-pentadecanoic acid (DMIPP) was studied in cardiomyopathic (CM) and normal age-matched Syrian hamsters. Dual tracer quantitative wholebody autoradiography (QARG) with DMIPP and 2-(/sup 14/C(U))-2-deoxy-2-fluoro-D-glucose (FDG) or with FDG and /sup 201/Tl enabled comparison of the uptake of a fatty acid and a glucose analog with the blood flow. These comparisons were carried out at the onset and mid-stage of the disease before congestive failure developed. Groups of CM and normal animals were treated with verapamil from the age of 26 days, before the onset of the disease for 41 days. In CM hearts, areas of decreased DMIPP uptake were seen. These areas were much larger than the decrease in uptake of FDG or /sup 201/Tl. In early CM only minimal changes in FDG or /sup 201/Tl uptake were observed as compared to controls. Treatment of CM-prone animals with verapamil prevented any changes in DMIPP, FDG, or /sup 201/Tl uptake. DMIPP seems to be a more sensitive indicator of early cardiomyopathic changes as compared to /sup 201/Tl or FDG. The trial of DMIPP and SPECT in the diagnosis of human disease, as well as for monitoring the effects of drugs which may prevent it seems to be warranted.

  11. Effect of eating on thallium myocardial imaging

    SciTech Connect

    Wilson, R.A.; Sullivan, P.J.; Okada, R.D.; Boucher, C.A.; Morris, C.; Pohost, G.M.; Strauss, H.W.

    1986-02-01

    To determine if eating between initial and delayed thallium images alters the appearance of the delayed thallium scan, a prospective study was performed; 184 subjects sent for routine thallium imaging were randomized into two groups, those who ate a meal high in carbohydrates between initial and delayed thallium myocardial images (n = 106), and those who fasted (n = 78). The /sup 201/Tl images were interpreted in blinded fashion for global myocardial and pulmonary clearance of /sup 201/Tl myocardial defects. The eating group had a significantly lower incidence of transient myocardial defects compared to the noneating group (7 percent vs 18 percent, respectively; p less than 0.05). The time between initial and delayed images and the incidence of exercise-induced ischemic ST-segment depression or pathologic Q waves on the electrocardiogram were not significantly different between the two groups. These data suggest that eating a high-carbohydrate meal between initial and delayed /sup 201/Tl images causes increased /sup 201/Tl myocardial clearance rates and may alter /sup 201/Tl myocardial redistribution over time.

  12. Mycobacterium tuberculosis DosR is Required for Activity of the PmbtB and PmbtI Promoters under Hypoxia

    PubMed Central

    Schreuder, Lise J.; Parish, Tanya

    2014-01-01

    Mycobacterium tuberculosis has the ability to survive for extended periods of time under conditions of low oxygen, low pH, low iron and low nutrients. The mycobactins (M. tuberculosis siderophores) play a key role in scavenging iron from the environment and are induced in response to low iron in an IdeR-regulated manner. We demonstrate that the promoters of two mycobactin gene (mbt) operons are also expressed during adaptation to low oxygen, and that this expression is dependent on the DosR regulator. Up-regulation of mbt operons induced by low iron was not DosR-dependent. DosR is a member of a two component regulatory system which responds to oxygen availability. Deletion of the DosR regulator led to increased expression of bacterioferritin and increased capacity to grow under iron depletion. These data provide a link between the mycobacterial response to two conditions likely to be encountered in vivo, low iron and low oxygen. PMID:25211224

  13. Dynamics of the T cell response to Mycobacterium tuberculosis DosR and Rpf antigens in a Colombian population of household contacts of recently diagnosed pulmonary tuberculosis patients.

    PubMed

    Arroyo, Leonar; Rojas, Mauricio; Ortíz, Blanca L; Franken, Kees L M C; García, Luis F; Ottenhoff, Tom H M; Barrera, Luis F

    2016-03-01

    Immune response to DosR and Rpf antigens from Mycobacterium tuberculosis (Mtb) seems to be important for latency maintenance. Little is known about the dynamics of the immune response to these antigens in an endemic community. Thus, the IFNγ response and cytokine production in response to PPD, Esat6-Cfp10 (E6-C10), DosR and Rpf antigens in healthy HHC of tuberculosis (TB) patients over a 12 (T12) months period (short-term, stLTBI) was investigated. This response was compared with a group of LTBI, who have remained healthy for 5-7 years (long-term, ltLTBI). According to the IFNγ response, two groups of HHCs were identified in stLTBI in response to E6-C10. At T12, E6-C10(+) HHCs displayed a decrease in the IFNγ levels and a generalized decrease in cytokines production. The E6-C10(-) HHC showed an increase in the IFNγ response and cytokine levels. In stLTBI, the responses to E6-C10, DosR, and Rpf may be interpreted as a protective immune response controlling Mtb infection and may be leading to a state of latent infection. Comparing the response of stLTBI and ltLTBI, we observed significant changes in the proportions of CD45RO(+)CD27(+) T cells to specific DosR and Rpf, which may indicate a persistent immune response to Mtb antigens in ltLTBI.

  14. A DOS-based Version of the VICAR Image Processing System for Planetary Image Reduction, Navigation, and Measuring

    NASA Astrophysics Data System (ADS)

    Hockey, T.; Barnet, C.

    1994-05-01

    The Video Image Communication and Retrieval (VICAR) Image Processing System, developed by the JPL Multimission Image Processing Laboratory, has been a standard tool for analyzing space-probe images since the 1960s. VMS versions through 8.0 are available. Yet now, the advent of powerful, inexpensive microcomputers has made possible "desktop" image processing. Here, a set of software that parallels VICAR routines, and expands upon them, is presented, written for the DOS operating system. PC VICAR was written in Microsoft FORTRAN by Chris Barnet for use on a 386-based microcomputer. Other hardware requirements include a Wieland Systems Design PCIP100A board and a separate video monitor for use as a display device. A CD-ROM drive is a convenient way of accessing raw Voyager images in PDS format. PC VICAR was developed at New Mexico State University. An upgraded version is being tested at the University of Northern Iowa (UNI). This version accepts images in a variety of formats including Voyager, HST, Galileo, and those used with ground-based detectors. The software is user-friendly, and extra effort has been made to make the Voyager image-processing tasks simple and easy to understand. At UNI, we propose to provide other observers with image navigation and measurements of features associated with the collision of comet Shoemaker-Levy and Jupiter in July, 1994. Funding for this project was provided in part by the NASA/University Joint Venture (JOVE) Program.

  15. Groundwater radon, radium and uranium concentrations in Região dos Lagos, Rio de Janeiro State, Brazil.

    PubMed

    Almeida, R M R; Lauria, D C; Ferreira, A C; Sracek, O

    2004-01-01

    Ground water from Região dos Lagos, a coastal area of Rio de Janeiro state, was analysed for (226)Ra, (228)Ra, (222)Rn, (238)U, major ion concentrations, and physico-chemical parameters were also measured. Concentrations values ranged from <0.002 to 0.492 Bq l(-1) for (226)Ra, from <0.01 to 1.50 Bq l(-1) for (228)Ra and from < 1.0 x 10(-4) to 8.0 x 10(-2) Bq l(-1) for (238)U. Detectable (222)Rn concentrations (>3 Bq l(-1)) were found only in two samples. The spatial distribution of Ra concentration delineated one distinct area and some hot spots with high Ra concentration. Low pH value is the most important water parameter linked to high radium concentration. This is probably related to limited adsorption of radium on soil ferric oxides and hydroxides at low pH range. There was a significant correlation between uranium concentrations and electrical conductivity values, and also between uranium concentrations and concentrations of Ca, Mg, Na, K, and Cl, indicating sea water impact. Uranium concentrations were lower than maximum contaminant level for drinking water, whereas 17 out of the 88 ground water samples had levels of radium that exceeded the maximum contaminant level for tap water. The total annual effective dose for adult due to the water consumption reaches values up to 0.8 mSv.

  16. A new species of Rock-Dwelling Scinax Wagler (Anura: Hylidae) from Chapada dos Veadeiros, Central Brazil.

    PubMed

    Araujo-Vieira, Katyuscia; Brandão, Reuber Albuquerque; Faria, Daniele Carvalho Do Carmo

    2015-01-01

    A new species of the Scinax ruber clade is described from Chapada dos Veadeiros region, Central Brazil. The new species is diagnosed by having SVL 21.9-27.7 mm in males and 26.7-31.7 mm in females; snout acuminate in dorsal view and rounded in profile; medium-sized tympanum; vocal sac single, median, subgular, that does not reach the pectoral region; iris iridescent yellow, with some thin, darker reticulations; tadpoles with ventral oral disc; P-3 regular and unmodified as a labial arm; absence of keratinized and colored plates on the sides of the lower jaw-sheath; presence of a keratinized and colored spur on each side behind the lower jaw-sheath; dorsolateral eyes, ventrally invisible; and advertisement call composed of 8-14 notes each with 4-18 pulses, and duration of 290-420 ms. The new species uses temporary creeks in rock meadows above 1.000 m a.s.l. and males calls from rock outcrops. The dorsal color pattern enables this species to camouflage in this kind of surfaces.  PMID:25662110

  17. Thallium-201 scintigraphy for diagnosis of old myocardial infarction: comparison with electrocardiographic, ventriculographic, and coronary arteriographic findings.

    PubMed Central

    Uthurralt, N; Parodi, O; Severi, S; Davies, G; Maseri, A

    1980-01-01

    Myocardial scintigraphy with 201Tl was performed at rest in a selected group of 36 patients with unequivocal clinical and electrocardiographic evidence of old myocardial infarction. The scintigraphic findings were correlated with electrocardiographic pattern, and with regional left ventricular wall motion and the severity of coronary artery disease defined by contrast angiography. Detection was dependent on the extent of the infarct but was independent of QRS morphology and of the severity of coronary disease. When positive, 201Tl scintigraphy was often a more precise method than the electrocardiogram for localising and delineating the extent of the infarct. Furthermore, the perfusion defect corresponded in location and extent to abnormalities of left ventricular wall motion. The site or severity of coronary artery disease could not be determined from the 201Tl scintigram. Images PMID:7378212

  18. A prospective comparison of rubidium-82 PET and thallium-201 SPECT myocardial perfusion imaging utilizing a single dipyridamole stress in the diagnosis of coronary artery disease

    SciTech Connect

    Go, R.T.; Marwick, T.H.; MacIntyre, W.J.; Saha, G.B.; Neumann, D.R.; Underwood, D.A.; Simpfendorfer, C.C. )

    1990-12-01

    The purpose of the present study is to prospectively compare myocardial perfusion imaging with rubidium-82 ({sup 82}Rb) by positron emission tomography (PET) with thallium-201 ({sup 201}Tl) imaging by single-photon emission tomography (SPECT) by recording both studies with a single dipyridamole handgrip stress, and reading both sets of images with the same display technique. In a series of 202 patients with previous coronary arteriography, the sensitivity, specificity, and accuracy of {sup 82}Rb PET were 93%, 78%, and 90% and for {sup 201}Tl SPECT 76%, 80%, and 77%, respectively. When 70 patients with previous therapeutic interventions were excluded, the remaining 132 patients showed a sensitivity, specificity, and accuracy of 95%, 82% and 92% for {sup 82}Rb PET and 79%, 76%, and 78% for {sup 201}Tl SPECT. The improved contrast resolution of PET resulted in markedly superior images and a more confident identification of defects.

  19. Effects of Unintentional Denial of Service (DOS) Due to Push-to-Talk (PTT) Delays on Performance of CSMA/CA Based Adhoc Land Mobile Radio (LMR) Networks

    NASA Astrophysics Data System (ADS)

    Navalekar, Abhijit C.; Michalson, William R.

    Unintentional Denial of Service (DOS) problems occur in wireless networks such as Wi-Fi due to factors such as signal capture, interference and have been studied extensively in the literature. A similar problem manifests amongst nodes within a LMR network due to different PTT delay characteristics. We first present the typical PTT delay values and distributions followed by an analytical model to estimate the denial of service problem. The results obtained using the model and simulations show that the LMR nodes experience DOS due to collisions resulting from PTT delays. The results also show that there exists an asymmetry in the performance of individual nodes and the extent of this asymmetry is a function of total number of nodes in the system and the density of nodes with similar PTT delay profiles. These observations have implications in both performance and capacity planning of an adhoc LMR network.

  20. Chemotaxis cluster 1 proteins form cytoplasmic arrays in Vibrio cholerae and are stabilized by a double signaling domain receptor DosM.

    PubMed

    Briegel, Ariane; Ortega, Davi R; Mann, Petra; Kjær, Andreas; Ringgaard, Simon; Jensen, Grant J

    2016-09-13

    Nearly all motile bacterial cells use a highly sensitive and adaptable sensory system to detect changes in nutrient concentrations in the environment and guide their movements toward attractants and away from repellents. The best-studied bacterial chemoreceptor arrays are membrane-bound. Many motile bacteria contain one or more additional, sometimes purely cytoplasmic, chemoreceptor systems. Vibrio cholerae contains three chemotaxis clusters (I, II, and III). Here, using electron cryotomography, we explore V. cholerae's cytoplasmic chemoreceptor array and establish that it is formed by proteins from cluster I. We further identify a chemoreceptor with an unusual domain architecture, DosM, which is essential for formation of the cytoplasmic arrays. DosM contains two signaling domains and spans the two-layered cytoplasmic arrays. Finally, we present evidence suggesting that this type of receptor is important for the structural stability of the cytoplasmic array. PMID:27573843

  1. Structural and electronic properties of protein/thiolate-protected gold nanocluster with ``staple'' motif: A XAS, L-DOS, and XPS study

    NASA Astrophysics Data System (ADS)

    Simms, Gordon A.; Padmos, J. Daniel; Zhang, Peng

    2009-12-01

    Following the recent breakthrough of total structural determination of a Au-thiolate nanocluster [P. Jadzinsky et al., Science 318, 430 (2007)], extensive interests have been stimulated to unveil (or revisit) the structure-property relationship of various thiolate-Au nanostructures in light of the new finding of -SR-(Au-SR)x- "staple" motif. Here, we present experimental x-ray absorption spectroscopy (XAS) and x-ray photoelectron spectroscopy (XPS) results on the local structure and electronic properties of thiolate-protected Au nanocluster encapsulated in bovine serum albumin (Au-BSA) together with theoretical calculation of projected local density of states (l-DOS) of Au25(SR)18 model cluster. Analysis of the Au L3-edge extended x-ray absorption fine structure (EXAFS) of Au-BSA suggested that the nanocluster is Au25 with Au-thiolate "staple" motif. X-ray absorption near-edge structure (XANES) and Au 4f XPS were used to probe the electronic behavior of Au-BSA. The Au d-electron density of Au-BSA was found to decrease by 0.047 e- relative to that of the bulk. A self-consistent real space Green's function approach implemented in ab initio FEFF8 program was used to calculate the l-DOS of Au25(SR)18 and other model clusters from a site-specific perspective. The theoretical results are in good agreement with the experimental d-DOS data of Au-BSA and, importantly, systematically illustrate the effect of Au-thiolate "staple" motif on the electronic behavior of Au25(SR)18. The present work sheds light on the structure-property relationship of thiolate-protected Au25 from both experimental and theoretical perspectives and illustrates the usefulness of XAS/l-DOS method in such studies.

  2. [Dual isotope myocardial scintigraphy (201thallium at rest/99 M technetium tetrofosmin with exercise) in the detection of reversible hypoperfusion].

    PubMed

    Peix González, A; López Díaz, A; Ponce Vicente, F; Maltas Pineda, A M; García Fernández, R; Barrera Sarduy, J D; García Barreto, D

    2000-02-01

    The dual-isotope technique (rest 201Tl and stress 99mTc-sestamibi) is useful to assess myocardial perfusion in coronary disease patients. 99mTc-labeled tetrofosmin is a radiopharmaceutical whose characteristics are similar to sestamibi. Thus, we decided to use it to detect reversible myocardial hypoperfusion in patients with a background of myocardial infarction and ischemia. A sequential dual-isotope scintigraphy (3 mCi rest 201Tl and 25 mCi stress 99mTc-tetrofosmin) with 24-hour 201Tl redistribution (RD) was performed in 20 patients with previously confirmed myocardial infarction and clinical and ergometric signs of ischemia. Each patient also underwent a stress-redistribution protocol with redistribution at 4 and 24 hours post injection with 201Tl scintigraphy within two weeks of the first study. The qualitative uptake analysis showed no significant differences in the number of myocardial segments with severe reduction of tracer uptake on stress that improved at rest or in RD images, even if 24-hour RD images were considered. The quantitative global uptake analysis showed a similar defect reversibility with both protocols; however if 24-hour RD images were considered the uptake improvement was significant only when compared with the rest 201Tl images in dual-isotope scintigraphy protocol (75+/-8% vs. 81+/-9% of peak activity, rest vs. 24-hour RD; p<0.01) and not when compared with the 4-hour RD in the 201Tl scintigraphy. On the other hand, when only the segments with severely reduced uptake (<50% of peak activity) were analyzed, the 24-hour RD improved myocardial uptake significantly (p<0.001 vs. rest and vs 4-hour RD) in both protocols. We conclude that a sequential dual-isotope rest 201Tl/stress 99mTc-tetrofosmin scintigraphy is comparable with stress-redistribution 201Tl scintigraphy to detect reversible myocardial hypoperfusion; however in both cases, the addition of 24-hour images increases its usefulness in severely hypoperfused segments, if the uptake of

  3. Longitudinal Evaluation of Sympathetic Nervous System and Perfusion in Normal and Spontaneously Hypertensive Rat Hearts with Dynamic Single-Photon Emission Computed Tomography.

    PubMed

    Zan, Yunlong; Boutchko, Rostyslav; Huang, Qiu; Li, Biao; Chen, Kewei; Gullberg, Grant T

    2015-01-01

    The objective of this work was to evaluate the sympathetic nervous system and structure remodeling during the progression of heart failure in a rodent model using dynamic cardiac single-photon emission computed tomography (SPECT). The spontaneously hypertensive rat (SHR) model was used to study changes in the nervous system innervation and perfusion in the left ventricular (LV) myocardium with the progression of left ventricular hypertrophy (LVH) to heart failure. Longitudinal dynamic SPECT studies were performed with seven SHR and seven Wistar-Kyoto (WKY) rats over 1.5 years using a dual-head SPECT scanner with pinhole collimators. Time-activity curves (TACs) of the 123I-MIBG and 201Tl distribution in the LV blood pool and myocardium were extracted from dynamic SPECT data and fitted to compartment models to determine the influx rate, washout rate, and distribution volume (DV) of 123I-MIBG and 201Tl in the LV myocardium. The standardized uptake values (SUVs) of 123I-MIBG and 201Tl in the LV myocardium were also calculated from the static reconstructed images. The influx and washout rates of 123I-MIBG did not show a significant difference between SHRs and WKY rats. The DVs of 123I-MIBG were greater in the SHRs than in the WKY rats (p = .0028). Specifically, the DV of 123I-MIBG became greater in the SHRs by 6 months of age (p = .0017) and was still significant at the age of 22 months. The SUV of 123I-MIBG in SHRs exhibited abnormal values compared to WKY rats from the age of 18 months. There was no difference in the influx rate and the washout rate of 201Tl between the SHRs and WKY rats. The SHRs exhibited greater DV of 201Tl than WKY rats after the age of 18 months (p = .034). The SUV of 201Tl in SHRs did not show any significant difference from WKY at all ages. The higher DV of 123I-MIBG in the LV myocardium reveals abnormal nervous system activity of the SHRs at an age of 6 months, whereas a greater DV of 201Tl in the LV myocardium can only be detected at an age

  4. En la búsqueda de características en eyecciones coronales de masa que discriminen entre dos paradigmas físicos en modelos de ECMs

    NASA Astrophysics Data System (ADS)

    Paissan, G.; Stenborg, G.; Rovira, M.

    Se conocen tres diferentes fenómenos de gran escala que ocurren en la atmósfera solar, denominados eyecciones coronales de masa (ECMs), protuberancias eruptivas y grandes fulguraciones de dos bandas. Estos fenómenos están estrechamente relacionados y podrían ser distintas manifestaciones de un único proceso físico. Las ECMs son definidas como eyecciones de gran escala de masa y flujo magnético desde la baja corona al espacio interplanetario. Desde su descubrimiento en los '70, muchos modelos han sido propuestos para explicar su origen y evolución. La explicación física de las ECMs es un tema de debate intenso. No obstante, los modelos pueden sintetizarse en dos grandes grupos: 1) los modelos de inyección de flujo y 2) los modelos de almacenamiento y liberación. En este trabajo, se presentan los estudios realizados con una serie de eventos observados con el coronógrafo MICA (Mirror Coronograph for Argentina), el telescopio en H-alfa HASTA (H-alpha Solar Telescope for Argentina) y los coronógrafos C2 y C3 de la sonda SOHO (Solar and Heliospheric Observatory). Los eventos que pudieron ser identificados como ECMs son contrastados dentro del esquema de los dos paradigmas teóricos propuestos.

  5. Queda dos homicídios em São Paulo, Brasil: uma análise descritiva

    PubMed Central

    Peres, Maria Fernanda Tourinho; Vicentin, Diego; Nery, Marcelo Batista; de Lima, Renato Sérgio; de Souza, Edinilsa Ramos; Cerda, Magdalena; Cardia, Nancy; Adorno, e Sérgio

    2012-01-01

    Objetivo Descrever a evolução da mortalidade por homicídios no Município de São Paulo segundo tipo de arma, sexo, raça ou cor, idade e áreas de exclusão/inclusão social entre 1996 e 2008. Métodos Estudo ecológico de série temporal. Os dados sobre óbitos ocorridos no Município foram coletados da base de dados do Programa de Aprimoramento das Informações sobre Mortalidade, seguindo a Classificação Internacional de Doenças, Décima Revisão (CID-10). Foram calculadas as taxas de mortalidade por homicídio (TMH) para a população total, por sexo, raça ou cor, faixa etária, tipo de arma e área de exclusão/inclusão social. As TMH foram padronizadas por idade pelo método direto. Foram calculados os percentuais de variação no período estudado. Para as áreas de exclusão/inclusão social foram calculados os riscos relativos de morte por homicídio. Resultados As TMH apresentaram queda de 73,7% entre 2001 e 2008. Foi observada redução da TMH em todos os grupos analisados, mais pronunciada em homens (−74,5%), jovens de 15 a 24 anos (−78,0%) e moradores de áreas de exclusão social extrema (−79,3%). A redução ocorreu, sobretudo, nos homicídios cometidos com armas de fogo (−74,1%). O risco relativo de morte por homicídio nas áreas de exclusão extrema (tendo como referência áreas com algum grau de exclusão social) foi de 2,77 em 1996, 3,9 em 2001 e 2,13 em 2008. Nas áreas de alta exclusão social, o risco relativo foi de 2,07 em 1996 e 1,96 em 2008. Conclusões Para compreender a redução dos homicídios no Município, é importante considerar macrodeterminantes que atingem todo o Município e todos os subgrupos populacionais e microdeterminantes que atuam localmente, influenciando de forma diferenciada os homicídios com armas de fogo e os homicídios na população jovem, no sexo masculino e em residentes em áreas de alta exclusão social. PMID:21390415

  6. [Species from genus Eimeria observed in domestic rabbit (Oryctolagus cuniculus) feces raised at the Municipality of Campos dos Goytacazes in the State of Rio de Janeiro, Brazil].

    PubMed

    de Almeida, Adriana J; Mayen, Friederike L; de Oliveira, Francisco C R

    2006-01-01

    This study was designed to identify species of the genus Eimeria from eleven rabbit meat breeders from Campos dos Goytacazes. Fecal samples were collected from rabbits with different health conditions and consintence of feces. The following species of Eimeria were identified: E. perforans; E. magna; E. coecicola; E. irresidua; E. media; E. flavescens; E. nagpurensis; E. intestinalis, E. exigua and E. stiedae. Parasites from this genus were detected in 81.82% (9) of the rabbit meat production sites, regardless of the management and hygiene conditions. In all cases the infection was always caused from more than one species of Eimeria. PMID:17196120

  7. Detection of IgG1 antibodies against Mycobacterium tuberculosis DosR and Rpf antigens in tuberculosis patients before and after chemotherapy.

    PubMed

    Mattos, Ana Márcia Menezes; Chaves, Alexandre Silva; Franken, Kees L M C; Figueiredo, Bárbara Bruna Muniz; Ferreira, Ana Paula; Ottenhoff, Tom H M; Teixeira, Henrique Couto

    2016-01-01

    Diagnosis of tuberculosis (TB) remains challenging. Serum IgG1 antibodies against Mycobacterium tuberculosis active growth phase antigens (ESAT-6/CFP-10, Rv0717 and Rv3353), DosR regulon-encoded proteins (Rv1733, Rv1737, Rv2628 and Rv2029), and resuscitation-promoting factors (Rv0867 and Rv2389) were evaluated in TB patients using ELISA. Active TB patients showed elevated levels of IgG1 antibodies against ESAT-6/CFP-10, Rv0717, Rv3353, Rv1733, Rv2628, Rv2029 and Rv0867 in comparison to healthy controls (p < 0.001). These levels remained high after the initiation of treatment, while responses to Rv0717 and Rv1733 peaked early during treatment. IgG1 responses to ESAT-6/CFP-10, Rv3353, Rv2628, Rv2029 and Rv0867 declined to control levels after the completion of 6 months chemotherapy. ROC analysis confirmed the good diagnostic performance of Rv0717, Rv1733, Rv3353, Rv2628, Rv2029 and Rv0867antigens. These data suggest that detecting IgG1 antibodies against M. tuberculosis antigens, including DosR and Rpf proteins, may represent an additional tool in the diagnosis of tuberculosis.

  8. Mycobacterium tuberculosis DosR Regulon Gene Rv0079 Encodes a Putative, ‘Dormancy Associated Translation Inhibitor (DATIN)’

    PubMed Central

    Kumar, Ashutosh; Majid, Mohammad; Kunisch, Ralph; Rani, Pittu Sandhya; Qureshi, Insaf A.; Lewin, Astrid; Hasnain, Seyed E.; Ahmed, Niyaz

    2012-01-01

    Mycobacterium tuberculosis is a major human pathogen that has evolved survival mechanisms to persist in an immune-competent host under a dormant condition. The regulation of M. tuberculosis metabolism during latent infection is not clearly known. The dormancy survival regulon (DosR regulon) is chiefly responsible for encoding dormancy related functions of M. tuberculosis. We describe functional characterization of an important gene of DosR regulon, Rv0079, which appears to be involved in the regulation of translation through the interaction of its product with bacterial ribosomal subunits. The protein encoded by Rv0079, possibly, has an inhibitory role with respect to protein synthesis, as revealed by our experiments. We performed computational modelling and docking simulation studies involving the protein encoded by Rv0079 followed by in vitro translation and growth curve analysis experiments, involving recombinant E. coli and Bacille Calmette Guérin (BCG) strains that overexpressed Rv0079. Our observations concerning the interaction of the protein with the ribosomes are supportive of its role in regulation/inhibition of translation. We propose that the protein encoded by locus Rv0079 is a ‘dormancy associated translation inhibitor’ or DATIN. PMID:22719925

  9. Católicos, fidelidade conjugal e AIDS: entre a cruz da doutrina moral e as espadas do cotidiano sexual dos adeptos1

    PubMed Central

    Rios, Luis Felipe; de Aquino, Francisca Luciana; Muñoz-Laboy, Miguel; Oliveira, Cinthia; Parker, Richard

    2009-01-01

    Neste artigo discutimos a visão da Igreja Católica sobre sexualidade na interface com a epidemia do HIV/AIDS. Nossa reflexão está embasada em pesquisa etnográfica que envolveu dois meses de observação participante do cotidiano de católicos de um bairro popular da Região Metropolitana do Recife, além de contar com entrevistas a onze dos leigos engajados nos serviços religiosos da igreja do bairro e a oito sacerdotes que realizam seus trabalhos religiosos em outras localidades. Nelas abordamos diferentes temáticas relacionadas ao enfrentamento da epidemia da AIDS. Nesse contexto, conjugalidade e fidelidade se afiguram como importantes analisadores de como aqueles lidam com a epidemia, em uma variedade de re-descrições práticas e de re-interpretações conceptuais das assertivas do discurso moral religioso – ainda que, muitos impasses permaneçam em aberto em termos das prerrogativas da Igreja e seus possíveis rebatimentos na saúde sexual dos adeptos. PMID:21765650

  10. Qual o Papel da Escola e da Mídia na Obtenção dos Conhecimentos Astronômicos?

    NASA Astrophysics Data System (ADS)

    da Cunha, W. S.; Voelzke, M. R.; Amaral, L. H.

    2007-08-01

    É amplamente reconhecido que as pessoas em geral têm grande fascínio e interesse pela Astronomia. Por outro lado, o conteúdo dessa área incluído no ensino formal está longe de ser abrangente e suficiente para suprir a demanda. Esse interesse permite aperfeiçoar a divulgação e o ensino não formal de Astronomia através da mídia aliando a adequação do conteúdo à expectativa das pessoas. A reforma do Currículo Básico da Escola Pública da maioria dos Estados brasileiros tem introduzido Astronomia desde a pré-escola até o Ensino Médio. Num estudo realizado com 1180 alunos do Ensino Médio de seis escolas estaduais, revelou-se através da aplicação de um formulário contendo questões que abordavam conhecimentos básicos em Astronomia, como foram adquiridos tais conhecimentos e à infra-estrutura da escola. Para 66,1% dos entrevistados o professor já fez alguma apresentação a respeito de Astronomia. O presente estudo revelou também que 54,4% dos alunos entrevistados adquiriram seus conhecimentos astronômicos na escola, 18,4% através da televisão e 27,1% afirmaram que seus conhecimentos foram obtidos através de outros tipos de mídia (internet, livros didáticos, filmes e revistas). Embora o estudo revele claramente que há certo equilíbrio no meio em que os alunos obtiveram seus conhecimentos astronômicos, a mídia busca não somente sua difusão, mas a disponibilização desse conhecimento de maneira correta, que às vezes, não é atingido, apresentando conceitos sem fundamentação e incorretos. Por outro lado, no dia-a-dia escolar, é comum encontrar professores que vêm para as aulas com concepções prévias, que podem diferir substancialmente das idéias a serem ensinadas, dificultando o aprendizado de futuros conceitos científicos. Uma avaliação criteriosa, avaliando as dificuldades dos professores em determinar o sentido correto dos conceitos e observando a metodologia que utilizam no ensino, poderá proporcionar uma melhor

  11. A Influência da Escola e da Mídia na Obtenção dos Conhecimentos Astronômicos

    NASA Astrophysics Data System (ADS)

    da Cunha, W. S.; Voelzke, M. R.; Amaral, L. H.

    2006-08-01

    O universo em que vivemos possui segredos jamais imaginados pelo homem, fruto da pequena proporção que ocupamos diante de um cosmos infinito. A astronomia funciona como um instrumento que sacia a sede humana em desvendar esses segredos, estudando as galáxias, quasares, pulsares além da existência de todos os elementos que preenchem o espaço cósmico, o vácuo, não mais vazio como se pensou em outros tempos. A mídia explora esse campo de forma mística e também científica. A difusão adequada e dentro dos padrões educacionais vigentes, de conceitos astronômicos, se faz necessária, devido sua presença nos conteúdos escolares, centros de ciência e na mídia, de modo geral. A reforma do Currículo Básico da Escola Pública da maioria dos Estados brasileiros introduziu conceitos astronômicos desde a pré-escola até o Ensino Médio. Num estudo realizado com 1.032 alunos do Ensino Médio de seis escolas estaduais, revelou-se através da aplicação de um questionário que abordava conheciment os básicos em astronomia, como estes foram adquiridos e qual era a infra-estrutura oferecida pela escola: para 66,2% dos entrevistados o professor já fez alguma apresentação a respeito de astronomia. O presente estudo revelou também que 44,5% dos alunos entrevistados adquiriram seus conhecimentos astronômicos na escola, 28,1% através da televisão e 27,4% afirmaram que seus conhecimentos foram obtidos através de outros tipos de mídia (internet, filmes e revistas). Embora o estudo revele claramente que há certo equilíbrio na forma em que os alunos obtiveram seus conhecimentos astronômicos, a mídia ainda explora e muitas vezes desperta o interesse pela astronomia com assuntos que não fazem parte de nosso cotidiano como, por exemplo, o homem na Lua, os projetos espaciais e a primeira viagem de um astronauta brasileiro no espaço. Porém, em certos casos, a mídia pode promover conhecimentos incompletos ou mesmo equivocados sobre os conceitos que envolvam

  12. Dipyridamole thallium-201 scintigraphy as a preoperative screening test. A reexamination of its predictive potential. Study of Perioperative Ischemia Research Group

    SciTech Connect

    Mangano, D.T.; London, M.J.; Tubau, J.F.; Browner, W.S.; Hollenberg, M.; Krupski, W.; Layug, E.L.; Massie, B. )

    1991-08-01

    The authors examined the value of dipyridamole thallium-201 (201Tl) scintigraphy as a preoperative screening test for perioperative myocardial ischemia and infarction. They prospectively studied 60 patients undergoing elective vascular surgery. They performed 201Tl scintigraphy preoperatively and blinded all treating physicians to the results. Historical, clinical, laboratory, and physiological data were gathered throughout hospitalization. Myocardial ischemia was assessed during the intraoperative period using continuous 12-lead electrocardiography (ECG) and transesophageal echocardiography (TEE) and during the postoperative period using continuous two-lead ambulatory ECG. Adverse cardiac outcomes (cardiac death, myocardial infarction, unstable angina, severe ischemia, or congestive heart failure) were assessed daily throughout hospitalization. Twenty-two patients (37%) had defects that improved or reversed on delayed scintigrams (redistribution defects), 18 (30%) had persistent defects, and 20 (33%) had no defects on 201Tl scintigraphy. There was no association between redistribution defects and adverse cardiac outcomes: 54% (seven of 13) of adverse outcomes occurred in patients without redistribution defects, and the risk of an adverse outcome was not significantly increased in patients with redistribution defects. Consistent with these findings, there was also no association between redistribution defects and perioperative ischemia: 54% (19 of all 35) of perioperative ECG and TEE ischemic episodes and 58% (14 of 24) of severe ischemic episodes occurred in patients without redistribution defects. The sensitivity of 201Tl scintigraphy for perioperative ischemia and adverse outcomes ranged from 40% to 54%, specificity from 65% to 71%, positive predictive value from 27% to 47% and negative predictive value from 61% to 82%.

  13. False-negative dipyridamole-thallium-201 myocardial imaging after caffeine infusion

    SciTech Connect

    Smits, P.; Corstens, F.H.; Aengevaeren, W.R.; Wackers, F.J.; Thien, T. )

    1991-08-01

    The vasodilator effect of intravenously administered dipyridamole may be caused by an increase in endogenous plasma adenosine levels. The authors evaluated the effect of caffeine, an adenosine receptor antagonist, on the diagnostic results of dipyridamole-201Tl myocardial imaging in eight patients with coronary artery disease. Caffeine infusion significantly attenuated the dipyridamole-induced fall in blood pressure and the accompanied increase in heart rate. The infusion of dipyridamole alone resulted in chest pain and ST-segment depressions on the electrocardiogram in four patients, whereas none of these problems occurred when the tests were repeated after caffeine. In six of eight patients, caffeine was responsible for false-negative dipyridamole-201Tl tests. Semiquantitive scores of the dipyridamole-induced 201Tl perfusion defects were decreased by caffeine from 9.0 {plus minus} 0.9 to 2.0 {plus minus} 1.1 points (p less than 0.05). Computerized analysis revealed a caffeine-mediated reduction in the percent reversibility of the images from 46% {plus minus} 16% to 6% {plus minus} 10% (p less than 0.05). They conclude that the use of caffeinated products prior to dipyridamole-201Tl testing may be responsible for false-negative findings.

  14. Ribose facilitates thallium-201 redistribution in patients with coronary artery disease

    SciTech Connect

    Perlmutter, N.S.; Wilson, R.A.; Angello, D.A.; Palac, R.T.; Lin, J.; Brown, B.G. )

    1991-02-01

    To investigate whether i.v. infusion of ribose, an adenine nucleotide precursor, postischemia facilitates thallium-201 (201Tl) redistribution and improves identification of ischemic myocardium in patients with coronary artery disease (CAD), 17 patients underwent two exercise 201Tl stress tests, performed 1-2 wk apart. After immediate postexercise planar imaging, patients received either i.v. ribose (3.3 mg/kg/min x 30 min) or saline as a control. Additional imaging was performed 1 and 4 hr postexercise. Reversible defects were identified by count-profile analysis. Significantly more (nearly twice as many) reversible 201Tl defects were identified on the post-ribose images compared to the post-saline (control) images at both 1 and 4 hr postexercise (p less than 0.001). Quantitative analyses of the coronary arteriogram was available in 13 patients and confirmed that the additional reversible defects were in myocardial regions supplied by stenosed arteries. We conclude that ribose appears to facilitate 201Tl redistribution in patients with CAD and enhances identification of ischemic myocardium.

  15. ²⁰¹Tl⁺-labelled Prussian blue nanoparticles as contrast agents for SPECT scintigraphy.

    PubMed

    Perrier, M; Busson, M; Massasso, G; Long, J; Boudousq, V; Pouget, J-P; Peyrottes, S; Perigaud, Ch; Porredon-Guarch, C; de Lapuente, J; Borras, M; Larionova, J; Guari, Y

    2014-11-21

    Prussian blue (PB) and its analogues on the nanometric scale are exciting nano-objects that combine the advantages of molecular-based materials and nanochemistry. Herein, we demonstrate that ultra-small PB nanoparticles of 2-3 nm can be easily labelled with radioactive (201)Tl(+) to obtain new nanoprobes as radiotracers for 201-thallium-based imaging.

  16. Upward creep of the heart: A frequent source of false-positive reversible defects during thallium-201 stress-redistribution SPECT

    SciTech Connect

    Friedman, J.; Van Train, K.; Maddahi, J.; Rozanski, A.; Prigent, F.; Bietendorf, J.; Waxman, A.; Berman, D.S. )

    1989-10-01

    A new cause of artifactual {sup 201}Tl defects on single photon emission computed tomography (SPECT) termed upward creep of the heart is described. In 102 consecutive patients undergoing {sup 201}Tl SPECT, 30 (29%) demonstrated upward creep defined by an upward movement of the heart of greater than or equal to 2 pixels during acquisition. In 45 consecutive patients with a less than 5% likelihood of coronary artery disease, 17 (38%) had upward creep. Of these nine had reversible {sup 201}Tl defects localized to the inferior and basal inferoseptal walls, while none of the 28 without upward creep had defects. The 17 low likelihood patients with upward creep had longer exercise duration and higher peak heart rate than those without upward creep. In five additional low likelihood patients with upward creep in whom imaging was immediately repeated, the upward creep pattern disappeared on the repeated images. After we changed our test protocol to begin imaging 15 min postexercise, only five (14%) of 36 low likelihood patients tested demonstrated upward creep. Upward creep is probably related to a transient increase in mean total lung volume early following exhaustive exercise, resulting in a mean lower position of the diaphragm (and thus the heart) at the beginning of imaging. The frequency of this source of false-positive {sup 201}Tl studies can be reduced by delaying SPECT acquisition until 15 min postexercise.

  17. Geochemical and isotopic evidence for the petrogenesis and emplacement tectonics of the Serra dos Órgãos batholith in the Ribeira belt, Rio de Janeiro, Brazil

    NASA Astrophysics Data System (ADS)

    Machado, Rômulo; Philipp, Ruy Paulo; McReath, Ian; Peucat, Jean Jacques

    2016-07-01

    The Serra dos Órgãos batholith in the State of Rio de Janeiro (Brazil) is a NE-SW-trending elongated body that occupies ca. 5000 km2 in plan view. It is a foliated intrusion, especially at its borders and is crosscut by syn-magmatic shear zones, with foliations that are moderately-to steeply-dipping to the northwest and moderately-to shallow-dipping in the center and to the southeast, in a configuration of a large laccolith. It was emplaced between 560 and 570 Ma, during an extensional episode that was part of a series of events that comprise the Brasiliano Orogeny in SE Brazil, and which includes deformation, metamorphism and granite intrusion during the interval between 630 and 480 Ma. The two main rock types in the batholith are biotite-hornblende monzogranite, and biotite leucogranite, with subordinate tonalite, granodiorite, diorite, quartz diorite (enclaves), aplite and pegmatite. Harker-type diagrams help show two rock groups with similar trends of evolution: a dioritic and a granitic. The first one is tholeiitic, whereas the second is calc-alkaline, with medium-to high-K calc-alkaline affinity and metaluminous to slightly peraluminous character. In both groups strong decrease in Al2O3, MgO, FeOT and CaO relative to silica contents are observed, which is compatible with trends of fractional crystallization involving clinopyroxene and/or hornblende, plagioclase, opaque minerals, apatite, microcline and biotite. The Sr and Nd isotopic data suggest recycling of a Paleoproterozoic crust as an important petrological process to generate the batholith rocks. Geothermometry (amphibole composition) and geobarometry (saturation in zircon and apatite) indicate that most of the batholith solidified at mid to lower crustal levels at about 750 °C and between 5 and 5.5 kbar. We consider that Serra dos Órgãos crustal protoliths underwent melting caused by the interaction with hotter mafic magma at the base of the crust. These two magmas, with distinct initial

  18. A comparison of the overall first-pass kinetics of thallium-201 and technetium-99m MIBI in normoxic and low-flow ischaemic myocardium.

    PubMed

    Ayalew, A; Marie, P Y; Menu, P; Mertes, P M; Hassan, N; Danchin, N; Olivier, P; Karcher, G; Bertrand, A

    2000-11-01

    The specific impact of ischaemia on the myocardial kinetics of thallium-201 and technetium-99m 2-methoxy-2-isobutylisonitrile (MIBI) remains a matter of debate. Using an isolated heart model perfused with red blood cell-enhanced perfusate, we compared the overall first-pass kinetics of 201Tl and MIBI under haemodynamically stable conditions of low-flow ischaemia (> 50% reduction in normal coronary flow and a > or = 20 mmHg fall in systolic contraction pressure, n = 10) and normoxia (n = 11). For both 201Tl and MIBI, we found that under ischaemic conditions (as compared with normoxia) there was a higher initial net extraction fraction (201Tl: 0.78 +/- 0.03 vs 0.72 +/- 0.06, P = 0.006; MIBI: 0.49 +/- 0.10 vs 0.39 +/- 0.11, P = 0.03), a lower clearance rate in the 30 min following extraction (% decrease in cardiac uptake: 201Tl: 30 +/- 12 vs 47 +/- 14, P = 0.02; MIBI: 5 +/- 5 vs 13 +/- 11, P = 0.02) and a higher retention fraction at 30 min (20lTl: 0.54 +/- 0.10 vs 0.39 +/- 0.12, P = 0.004; MIBI: 0.46 +/- 0.08 vs 0.33 +/- 0.12, P = 0.01). Multivariate analyses, however, revealed that all myocardial kinetic parameters of both tracers were dependent only on coronary flow rates, without any additional significant impact of the presence of ischaemia or states of contractility or oxidative metabolism. We conclude that the myocardial fractional retention of both 201Tl and MIBI is strongly correlated with the decrease in coronary flow during ischaemia. This inverse relationship with coronary flow derives from both the flow-dependent increase in the initial myocardial extraction and the decrease in the subsequent myocardial washout of the tracers.

  19. Dobutamine echocardiography and thallium-201 imaging predict functional improvement after revascularisation in severe ischaemic left ventricular dysfunction.

    PubMed Central

    Senior, R.; Glenville, B.; Basu, S.; Sridhara, B. S.; Anagnostou, E.; Stanbridge, R.; Edmondson, S. J.; Handler, C. E.; Raftery, E. B.; Lahiri, A.

    1995-01-01

    OBJECTIVES--To evaluate the concordance between thallium-201 uptake and echocardiographic wall thickening, which are both indicators of potentially reversible myocardial dysfunction, in patients with chronic ischaemic left ventricular failure and to assess their relative contribution to predicting improvement in regional function after revascularisation in a subgroup. PATIENTS AND METHODS--45 patients with chronic ischaemic left ventricular dysfunction (mean (SD) ejection fraction 25 (8)%) underwent echocardiography before and after dobutamine infusion (10 micrograms/kg/min). Of these, 22 patients underwent rest echocardiography at a mean (SD) of 9 (1) weeks after revascularisation. 201Tl imaging was performed during dobutamine echocardiography and at rest, 1, and 4 h after treatment with sublingual glyceryl trinitrate on two separate days. Potentially reversible dysfunction was thought to be present when a myocardial segment contained a Tl score of > or = 3 (ascending score 1-4), or showed improved wall thickening of a dysynergic segment during dobutamine stimulation. RESULTS--Of the 201Tl protocols, the redistribution scan 1 h after treatment with glyceryl trinitrate best demonstrated myocardial viability. Concordance between 201Tl and dobutamine induced wall thickening was 82% (kappa = 0.59) for detecting potentially reversible myocardial dysfunction before revascularisation (n = 45). Regional function improved in 18 of 22 patients after revascularisation. There were 168 dysynergic segments before intervention. The sensitivity of echocardiography and 201Tl imaging for detecting "recoverable" or viable segments after revascularisation was 87% and 92% respectively and specificity was 82% and 78% respectively (P = NS). CONCLUSIONS--Dobutamine echocardiography and 201Tl imaging may be used to predict mechanical improvement in dysynergic segments after revascularisation in patients with chronic ischaemic left ventricular dysfunction. Images PMID:7488446

  20. [Evaluation of reconstruction arc in myocardial SPECT imaging using a cardiac phantom--comparison between 360 degrees and 180 degrees arcs].

    PubMed

    Kashikura, K; Kashikura, A; Terada, S; Kobayashi, H

    1996-10-01

    In order to investigate the effect of reconstruction arc on myocardial SPECT images, a series of phantom studies was performed with and without plastic chambers simulating perfusion defects using 201Tl and 99mTc. Coefficient of variations (CV) of the counts among the ROIs and defect contrast were evaluated in 360 degrees and 180 degrees images reconstructed from the same 360 degrees projection data. Reconstruction processes were identical for all images. In the absence of defects, the CV of the counts were approximately the same in 360 degrees and 180 degrees images. The CV of the counts in the 360 degrees 201Tl image, among 4 defects located on the anterior, lateral, inferoposterior, and septal walls, was superior to those in the 180 degrees images. In contrast, in the 99mTc images, the CV of the counts among the 4 defects in the 180 degrees image was superior to those of the 360 degrees image. The defect contrast was changed both by the location of the defect and by the reconstruction arc (201Tl, 99mTc). The defect contrast of the 180 degrees images, in both 201Tl and 99mTc experiments, was closer to the true contrast value as calculated by the count ratio between myocardium and defect. Although the defect contrast in the anterior, lateral and septal walls was more emphasized in the 180 degrees images, the defect contrast in the inferoposterior wall was less emphasized in the 180 degrees images compared to the 360 degrees (201Tl, 99mTc).

  1. Specific localization of thallium 201 in human high-grade astrocytoma by microautoradiography.

    PubMed

    Mountz, J M; Raymond, P A; McKeever, P E; Modell, J G; Hood, T W; Barthel, L K; Stafford-Schuck, K A

    1989-07-15

    The ability to accurately distinguish remaining or recurrent high-grade astrocytoma from necrosis or edema following treatment is essential to optimal patient management. Thallium 201 planar gamma-camera imaging has been shown to be helpful in detecting recurrent high-grade astrocytoma; however, due to tissue heterogeneity adjacent to and within tumor, the cellular specificity and quantification of 201Tl uptake are largely unknown. In order to determine which tissues are responsible for the radioisotope uptake, microautoradiographic techniques were used to examine multiple tissue sections from five patients with high-grade astrocytoma. Each patient received 5 mCi of 201Tl i.v. 1 h prior to tumor removal. Additionally, all patients received computerized tomographic and 201Tl planar gamma-camera scans prior to surgery. Following surgery, the excised tissue specimens were tentatively classified by gross pathological examination and then immediately processed for dry mount autoradiography; grain density was determined over regions containing tumor, adjacent and uninvolved brain tissue, necrotic tissue, and background. Highly significant differences were found in grain densities (201Tl uptake) between tumor and uninvolved brain tissue, as well as between uninvolved brain tissue and necrotic tissue; there was no significant difference between background grain density and that in necrotic tissue. Mean grain densities (grains/cm2 +/- 1 SD) across patients were: tumor, 102 +/- 23; adjacent, uninvolved brain tissue, 29 +/- 11; necrotic tissue, 6.2 +/- 1.1; and background, 7.0 +/- 4.1. We conclude that the ability of 201Tl to selectively image high-grade astrocytoma is due to its preferential uptake into tumor cells.

  2. A Multimodality Imaging Approach for Serial Assessment of Regional Changes in Lower Extremity Arteriogenesis and Tissue Perfusion in a Porcine Model of Peripheral Arterial Disease

    PubMed Central

    Stacy, Mitchel R.; Yu, Da Yu; Maxfield, Mark W.; Jaba, Irina M.; Jozwik, Bartosz P.; Zhuang, Zhen W.; Lin, Ben A.; Hawley, Christi L.; Caracciolo, Christopher M.; Pal, Prasanta; Tirziu, Daniela; Sampath, Smita; Sinusas, Albert J.

    2014-01-01

    Background A standard quantitative imaging approach to evaluate peripheral arterial disease (PAD) does not exist. Quantitative tools for evaluating arteriogenesis in vivo are not readily available and the feasibility of monitoring serial regional changes in lower extremity perfusion has not been examined. Methods and Results Serial changes in lower extremity arteriogenesis and muscle perfusion were evaluated following femoral artery occlusion in a porcine model using SPECT/CT imaging with post-mortem validation of in vivo findings using gamma counting, post-mortem imaging, and histological analysis. Hybrid thallium-201 (201Tl) SPECT/CT imaging was performed in pigs (n=8) at baseline, immediately post-occlusion, and at 1 and 4 weeks post-occlusion. CT imaging was used to identify muscle regions of interest in the ischemic (I) and non-ischemic (NI) hindlimbs for quantification of regional changes in CT defined arteriogenesis and quantification of 201Tl perfusion. Four weeks post-occlusion, post-mortem tissue 201Tl activity was measured by gamma counting and immunohistochemistry was performed to assess capillary density. Relative 201Tl retention (I/NI) was reduced immediately post-occlusion in distal and proximal muscles and remained lower in calf and gluteus muscles 4 weeks later. Analysis of CT angiography revealed collateralization at 4 weeks within proximal muscles (p<0.05). SPECT perfusion correlated with tissue gamma counting at 4 weeks (p=0.01). Increased capillary density was seen within the ischemic calf at 4 weeks (p=0.004). Conclusions 201Tl SPECT/CT imaging permits serial, regional quantification of arteriogenesis and resting tissue perfusion following limb ischemia. This approach may be effective for detection of disease and monitoring therapy in PAD. PMID:24170237

  3. Dual isotope thallium and indium antimyosin SPECT imaging to identify acute infarct patients at further ischemic risk

    SciTech Connect

    Johnson, L.L.; Seldin, D.W.; Keller, A.M.; Wall, R.M.; Bhatia, K.; Bingham, C.O. III; Tresgallo, M.E. )

    1990-01-01

    Forty-two patients (28 men and 14 women) with acute myocardial infarction (35 Q, seven non-Q wave) were injected with 2.0 mCi indium 111-labeled antimyosin (AM) monoclonal antibody (111In AM) within 48 hours of the onset of chest pain. Forty-eight hours later (72-96 hours after onset of chest pain), patients were injected with 2.2 mCi thallium 201, and two sets of single-photon emission computed tomography (SPECT) images were obtained simultaneously using dual energy windows set for the 247 keV indium photopeak and the 70 keV thallium peak. Seventeen patients had repeat scans at 4 hours. 111In AM uptake and 201Tl defects were localized to one or more of 24 coronal and sagittal segments. Scans with only 201Tl defects and corresponding 111In AM uptake were classified as matches; scans with unmatched 201Tl defects in addition to matching regions corresponding to electrocardiographic infarct location were classified as mismatches; and scans with 201Tl and 111In AM uptake in the same segments were classified as overlap. Scan patterns were correlated with clinical evidence for residual ischemia occurring within 6 weeks of infarct and including infarct extension, recurrent angina, and positive predischarge low-level or 6-week symptom-limited stress tests and with coronary anatomy. Fourteen patients had only matching patterns (group 1), 23 had mismatches (group 2), and five had 201Tl-111In overlap as the predominant pattern. None of the patients in group 1 had previous myocardial infarction; in each, the matched area corresponded to the Q wave location on electrocardiogram, and none had further in-hospital ischemic events or positive stress tests.

  4. A estabilidade dos PAHS em função da energia da radiação interestelar nas faixas UV e raios-X

    NASA Astrophysics Data System (ADS)

    Pinotti, R.; Costa, R. K.; Boechat-Roberty, H. M.; Lago, A.; Souza, G. B.

    2003-08-01

    A nebulosa CRL 618, uma proto-nebulosa planetária cuja nuvem molecular espessa envolve uma estrela B0, contém uma grande quantidade de C2H2 e CH4. Estas moléculas são consideradas os tijolos da criação de grandes moléculas carbonadas como os Hidrocarbonetos Policíclicos Aromáticos (PAHs). Esta nebulosa, por estar exposta a intensos campos de UV e Raios-X, é uma região de fotodissociação molecular que propicia a formação de novas moléculas, confirmada pela presença de C4H2 e C6H6 (Benzeno), que é a unidade básica dos PAHs. Atribui-se a esta família de moléculas orgânicas duas propriedades fundamentais, a resistência para sobreviver ao campo de radiação UV interestelar e a geração das bandas de emissão não identificadas (UIR) observadas no infravermelho. No entanto, alguns autores questionam a resistência dos PAHs ao campo de radiação UV interestelar. Empregando a técnica de Espectrometria de Massas por Tempo de Vôo, no modo de coincidência fotoelétron-fotoíon, estudamos a ionização e fragmentação das seguintes moléculas: Benzeno, Benzeno deuterado, Naftaleno, Antraceno e Fenantreno. Utilizamos uma fonte de Hélio monocromática em 21,21 eV (584,5 Å) e a radiação Síncroton do Laboratório Nacional de Luz Síncroton (LNLS) em diferentes energias nas proximidades da borda do C 1s ( 290 eV). Comprovamos a estabilidade dos PAHs sob ação de UV (21,21 eV), onde eles apresentam um baixo nível de fotodissociação, produzindo fragmentos ionizados com rendimento total na ordem de 5 por cento em relação ao íon molecular pai. Entretanto, em altas energias, na faixa de Raios-X, a quebra destas moléculas torna-se mais intensa, com a produção de muitos fragmentos. Como uma das rotas de fragmentação do Naftaleno é [(C10H8) = > (C6H6+) + (C4H2) + (e-)], e como temos as evidências observacionais da existência do C4H2 e C6H6 na nebulosa CRL 618, sugerimos que este ambiente também possui o Naftaleno.

  5. Mycobacterium tuberculosis DevR/DosR Dormancy Regulator Activation Mechanism: Dispensability of Phosphorylation, Cooperativity and Essentiality of α10 Helix

    PubMed Central

    Sharma, Saurabh; Tyagi, Jaya Sivaswami

    2016-01-01

    DevR/DosR is a well-characterized regulator in Mycobacterium tuberculosis which is implicated in various processes ranging from dormancy/persistence to drug tolerance. DevR induces the expression of an ~48-gene dormancy regulon in response to gaseous stresses, including hypoxia. Strains of the Beijing lineage constitutively express this regulon, which may confer upon them a significant advantage, since they would be ‘pre-adapted’ to the environmental stresses that predominate during infection. Aerobic DevR regulon expression in laboratory-manipulated overexpression strains is also reported. In both instances, the need for an inducing signal is bypassed. While a phosphorylation-mediated conformational change in DevR was proposed as the activation mechanism under hypoxia, the mechanism underlying constitutive expression is not understood. Because DevR is implicated in bacterial dormancy/persistence and is a promising drug target, it is relevant to resolve the mechanistic puzzle of hypoxic activation on one hand and constitutive expression under ‘non-inducing’ conditions on the other. Here, an overexpression strategy was employed to elucidate the DevR activation mechanism. Using a panel of kinase and transcription factor mutants, we establish that DevR, upon overexpression, circumvents DevS/DosT sensor kinase-mediated or small molecule phosphodonor-dependent activation, and also cooperativity-mediated effects, which are key aspects of hypoxic activation mechanism. However, overexpression failed to rescue the defect of C-terminal-truncated DevR lacking the α10 helix, establishing the α10 helix as an indispensable component of DevR activation mechanism. We propose that aerobic overexpression of DevR likely increases the concentration of α10 helix-mediated active dimer species to above the threshold level, as during hypoxia, and enables regulon expression. This advance in the understanding of DevR activation mechanism clarifies a long standing question as to

  6. Novas determinações dos parâmetros atmosféricos das estrelas anãs brancas DA

    NASA Astrophysics Data System (ADS)

    Giovannini, O.; Costa, A. F. M.; Kepler, S. O.

    2003-08-01

    Nós temos selecionado uma amostra de estrelas anãs brancas DA (atmosfera de hidrogênio) a partir dos índices de Strömgren cujos valores estão próximos a região de instabilidade das estrelas anãs brancas DA variáveis, as chamadas estrelas DAV ou ZZ Ceti. O objetivo é determinar os parâmetros fundamentais (temperatura efetiva, Teff, aceleração da gravidade, log g, e massa) destas estrelas para verificar quais os parâmetros estelares estão envolvidos com o mecanismo de pulsação das estrelas DAV. Nós obtemos, até agora, mais de 120 espectros óticos de estrelas DA. Entre as estrelas selecionadas há 20 estrelas variáveis (DAV). Assim, podemos verificar se existem ou não estrelas não variáveis dentro da faixa de instabilidade das estrelas ZZ Ceti. Neste trabalho nós apresentamos a determinação dos parâmetros atmosféricos (temperatura efetiva, Teff, e aceleração da gravidade, log g) das estrelas anãs brancas DA usando os novos modelos de atmosfera ML2/a = 0.6. Estes modelos têm sido utilizados recentemente por fornecerem uma excelente consistência interna na determinação das temperaturas nas regiões do ultra-violeta e ótico. Os parâmetros atmosféricos são determinados espectroscopicamente através da comparação do fluxo de energia das linhas de Balmer (Hb à H9) entre os espectros observados e sintéticos (gerados pelos modelos de atmosfera). As temperaturas obtidas com os novos modelos são, em geral, menores (~ 1000 K menos) que as temperaturas determinadas anteriormente, com modelos ML1. Os valores de log g não mudaram significativamente (menos de 10%). A faixa de instabilidade das DAVs está entre 11000 e 13000 K, consistente com dados de outros autores.

  7. Mycobacterium tuberculosis DevR/DosR Dormancy Regulator Activation Mechanism: Dispensability of Phosphorylation, Cooperativity and Essentiality of α10 Helix.

    PubMed

    Sharma, Saurabh; Tyagi, Jaya Sivaswami

    2016-01-01

    DevR/DosR is a well-characterized regulator in Mycobacterium tuberculosis which is implicated in various processes ranging from dormancy/persistence to drug tolerance. DevR induces the expression of an ~48-gene dormancy regulon in response to gaseous stresses, including hypoxia. Strains of the Beijing lineage constitutively express this regulon, which may confer upon them a significant advantage, since they would be 'pre-adapted' to the environmental stresses that predominate during infection. Aerobic DevR regulon expression in laboratory-manipulated overexpression strains is also reported. In both instances, the need for an inducing signal is bypassed. While a phosphorylation-mediated conformational change in DevR was proposed as the activation mechanism under hypoxia, the mechanism underlying constitutive expression is not understood. Because DevR is implicated in bacterial dormancy/persistence and is a promising drug target, it is relevant to resolve the mechanistic puzzle of hypoxic activation on one hand and constitutive expression under 'non-inducing' conditions on the other. Here, an overexpression strategy was employed to elucidate the DevR activation mechanism. Using a panel of kinase and transcription factor mutants, we establish that DevR, upon overexpression, circumvents DevS/DosT sensor kinase-mediated or small molecule phosphodonor-dependent activation, and also cooperativity-mediated effects, which are key aspects of hypoxic activation mechanism. However, overexpression failed to rescue the defect of C-terminal-truncated DevR lacking the α10 helix, establishing the α10 helix as an indispensable component of DevR activation mechanism. We propose that aerobic overexpression of DevR likely increases the concentration of α10 helix-mediated active dimer species to above the threshold level, as during hypoxia, and enables regulon expression. This advance in the understanding of DevR activation mechanism clarifies a long standing question as to the

  8. Pressure effects reveal that changes in the redox states of the heme iron complexes in the sensor domains of two heme-based oxygen sensor proteins, EcDOS and YddV, have profound effects on their flexibility.

    PubMed

    Anzenbacher, Pavel; Marchal, Stéphane; Palacký, Jan; Anzenbacherová, Eva; Domaschke, Thomas; Lange, Reinhard; Shimizu, Toru; Kitanishi, Kenichi; Stranava, Martin; Stiborová, Marie; Martinkova, Marketa

    2014-12-01

    The catalytic activity of a heme-based oxygen sensor phosphodiesterase from Escherichia coli (EcDOS) towards cyclic diGMP is regulated by the redox state of the heme iron complex in the enzyme's sensing domain and the association of external ligands with the iron center. Specifically, the Fe(II) complex is more active towards cyclic diGMP than the Fe(III) complex, and its activity is further enhanced by O2 or CO binding. In order to determine how the redox state and coordination of the heme iron atom regulate the catalytic activity of EcDOS, we investigated the flexibility of its isolated N-terminal heme-binding domain (EcDOS-heme) by monitoring its spectral properties at various hydrostatic pressures. The most active form of the heme-containing domain, i.e. the Fe(II)-CO complex, was found to be the least flexible. Conversely, the oxidized Fe(III) forms of EcDOS-heme and its mutants had relatively high flexibilities, which appeared to be linked to the low catalytic activity of the corresponding intact enzymes. These findings corroborate the suggestion, made on the basis of crystallographic data, that there is an inverse relationship between the flexibility of the heme-containing domain of EcDOS and its catalytic activity. The Fe(II)-CO form of the heme domain of a second heme-based oxygen sensor, diguanylate cyclase (YddV), was also found to be quite rigid. Interestingly, the incorporation of a water molecule into the heme complex of YddV caused by mutation of the Leu65 residue reduced the flexibility of this heme domain. Conversely, mutation of the Tyr43 residue increased its flexibility.

  9. Benzo-fused lactams from a diversity-oriented synthesis (DOS) library as inhibitors of scavenger receptor BI (SR-BI)-mediated lipid uptake.

    PubMed

    Dockendorff, Chris; Faloon, Patrick W; Pu, Jun; Yu, Miao; Johnston, Stephen; Bennion, Melissa; Penman, Marsha; Nieland, Thomas J F; Dandapani, Sivaraman; Perez, José R; Munoz, Benito; Palmer, Michelle A; Schreiber, Stuart L; Krieger, Monty

    2015-01-01

    We report a new series of 8-membered benzo-fused lactams that inhibit cellular lipid uptake from HDL particles mediated by Scavenger Receptor, Class B, Type I (SR-BI). The series was identified via a high-throughput screen of the National Institutes of Health Molecular Libraries Small Molecule Repository (NIH MLSMR), measuring the transfer of the fluorescent lipid DiI from HDL particles to CHO cells overexpressing SR-BI. The series is part of a previously reported diversity-oriented synthesis (DOS) library prepared via a build-couple-pair approach. Detailed structure-activity relationship (SAR) studies were performed with a selection of the original library, as well as additional analogs prepared via solution phase synthesis. These studies demonstrate that the orientation of the substituents on the aliphatic ring have a critical effect on activity. Additionally, a lipophilic group is required at the western end of the molecule, and a northern hydroxyl group and a southern sulfonamide substituent also proved to be optimal. Compound 2p was found to possess a superior combination of potency (av IC50=0.10μM) and solubility (79μM in PBS), and it was designated as probe ML312. PMID:25900219

  10. ASPECTS OF THE ECOLOGY OF PHLEBOTOMINES (Diptera: Psychodidae: Phlebotominae) IN AN AREA OF CUTANEOUS LEISHMANIASIS OCCURRENCE, MUNICIPALITY OF ANGRA DOS REIS, COAST OF RIO DE JANEIRO STATE, BRAZIL

    PubMed Central

    de Aguiar, Gustavo Marins; de Azevedo, Alfredo Carlos Rodrigues; de Medeiros, Wagner Muniz; Alves, João Ricardo Carreira; Rendeiro, Vanessa

    2014-01-01

    Over a complete two-year period, phlebotomine specimens were caught in an area of cutaneous leishmaniasis occurrence in the municipality of Angra dos Reis. A manual suction tube was used to catch phlebotomines on house walls, and also light traps in domestic and peridomestic settings and in the forest. This yielded 14,170 specimens of 13 species: two in the genus Brumptomyia and eleven in the genus Lutzomyia. L. intermedia predominantly in domestic and peridomestic settings, with little presence in the forest, with the same trend being found in relation to L. migonei, thus proving that these species have adapted to the human environment. L. fischeri appeared to be eclectic regarding location, but was seen to be proportionally more endophilic. L. intermedia and L. migonei were more numerous in peridomestic settings, throughout the year, while L. fischeri was more numerous in domestic settings except in March, April, May and September. From the prevalence of L. intermedia, its proven anthropophily and findings of this species naturally infected with Leishmania (Viannia) braziliensis, it can be incriminated as the main vector for this agent of cutaneous leishmaniasis in the study area, especially in the peridomestic environment. L. fischeri may be a coadjuvant in carrying the parasite. PMID:24626417

  11. Analysis of the Astronomical Concepts Presented by Teachers of Science, Physics, and Mathematics of São José dos Campos / SP Municipality

    NASA Astrophysics Data System (ADS)

    Pereira Gonzaga, Edson; Voelzke, Marcos Rincon

    2013-11-01

    The aim of this work is to conduct a survey of alternative conceptions about the basic concepts of Astronomy from schoolteachers in the City of São José dos Campos. This study covers the the state-run education system and complies with legal documents related to the curriculum of educational systems, such as the Curriculum of São Paulo State and the Parameters of the National Curriculum (PCN). Alternative conceptions, mentioned in Langhi (2009) as very important, were used, because it is believed that if a student can learn these concepts before the methodological intervention, it is possible to prepare contextualized presentations for teachers, and consequently students, to compare what they already know with the new information they obtain in the sessions at the digital mobile planetarium (DMP) of the Universidade Cruzeiro do Sul. Afterwards, they may discuss in a forum, in the form of debate, seeking to draw conclusions relevant to the topic, and transmitting the same to students in Basic Education (EB). This is a case study with a quantitative survey and a qualitative analysis of data on astronomical concepts collected through two questionnaires, one before and one after the intervention, respecting the implementation period of the study,- here called methodological intervention of content presentations at the mobile planetarium - and on respective discussions.

  12. A putative nitroreductase from the DosR regulon of Mycobacterium tuberculosis induces pro-inflammatory cytokine expression via TLR2 signaling pathway

    PubMed Central

    Peddireddy, Vidyullatha; Doddam, Sankara Narayana; Qureshi, Insaf A.; Yerra, Priyadarshini; Ahmed, Niyaz

    2016-01-01

    Tuberculosis caused by Mycobacterium tuberculosis is a global encumbrance and it is estimated that nearly one third population of the world acts as a reservoir for this pathogen without any symptoms. In this study, we attempted to characterise one of the genes of DosR regulon, Rv3131, a FMN binding nitroreductase domain containing protein, for its ability to alter cytokine profile, an essential feature of M. tuberculosis latency. Recombinant Rv3131 stimulated pro-inflammatory cytokines in THP-1 cells and human peripheral blood mononuclear cells in a time and dose dependent manner. In silico analyses using docking and simulations indicated that Rv3131 could strongly interact with TLR2 via a non-covalent bonding which was further confirmed using cell based colorimetric assay. In THP-1 cells treated with Rv3131 protein, a significant upsurge in the surface expression, overall induction and expression of mRNA of TLR2 was observed when analysed by flow cytometry, western blotting and real time PCR, respectively. Activation of TLR2 by Rv3131 resulted in the phosphorylation of NF- κβ. Results of this study indicate a strong immunogenic capability of Rv3131 elicited via the activation of TLR2 signalling pathway. Therefore, it can be surmised that cytokine secretion induced by Rv3131 might contribute to establishment of M. tuberculosis in the granulomas. PMID:27094446

  13. Aspects of the ecology of phlebotomines (Diptera: Psychodidae: Phlebotominae) in an area of cutaneous leishmaniasis occurrence, municipality of Angra dos Reis, coast of Rio de Janeiro State, Brazil.

    PubMed

    Aguiar, Gustavo Marins de; de Azevedo, Alfredo Carlos Rodrigues; Medeiros, Wagner Muniz de; Alves, João Ricardo Carreira; Rendeiro, Vanessa

    2014-01-01

    Over a complete two-year period, phlebotomine specimens were caught in an area of cutaneous leishmaniasis occurrence in the municipality of Angra dos Reis. A manual suction tube was used to catch phlebotomines on house walls, and also light traps in domestic and peridomestic settings and in the forest. This yielded 14,170 specimens of 13 species: two in the genus Brumptomyia and eleven in the genus Lutzomyia. L. intermedia predominantly in domestic and peridomestic settings, with little presence in the forest, with the same trend being found in relation to L. migonei, thus proving that these species have adapted to the human environment. L. fischeri appeared to be eclectic regarding location, but was seen to be proportionally more endophilic. L. intermedia and L. migonei were more numerous in peridomestic settings, throughout the year, while L. fischeri was more numerous in domestic settings except in March, April, May and September. From the prevalence of L. intermedia, its proven anthropophily and findings of this species naturally infected with Leishmania (Viannia) braziliensis, it can be incriminated as the main vector for this agent of cutaneous leishmaniasis in the study area, especially in the peridomestic environment. L. fischeri may be a coadjuvant in carrying the parasite. PMID:24626417

  14. Earth and Heavens: Two Separate Universes? (Spanish Title: Tierra y Cielos: ¿Dos Universos Separados?) Terra e Céus: Dois Universos Separados?

    NASA Astrophysics Data System (ADS)

    Carrascosa, Jaime; Gil-Pérez, Daniel; Solbes, Jordi; Vilches, Amparo

    2005-12-01

    complexidade, considerando, entre outros aspectos: as situações problemáticas relevantes que levaram à construção dos conhecimentos, as dificuldades de todo tipo que se teve que enfrentar nessa construção e, muito em particular,a necessidade de se superar as "evidências do senso comum" que estabeleciam uma suposta barreira intransponível entre a Terra e os Céus e que foram um obstáculo durante séculos para o desenvolvimento científico. Neste trabalho apresentamos um programa de atividades para o estudo da gravitação nos últimos anos do ensino médio, orientado a favorecer a participação dos estudantes, em alguma medida, na reconstrução deste processo que constituiu a denominada primeira grande revolução científica e a nos aproximarmos do estudo de uma das ciências mais antigas, a Astronomia, que hoje continua despertando grande interesse.

  15. Rb-Sr and Sm-Nd whole rock analyses of basalts of the Grao Para Group, Serra dos Carajas, Brazil

    SciTech Connect

    Olszewski, W.J. Jr.; Gibbs, A.K.; Wirth, K.R.

    1985-01-01

    The Grao Para Group at Serra dos Carajas in the Guapore Shield of Brazil is a 6 km thick sequence of bimodal metavolcanic rock with interbedded iron formations. Rhyolites are a minor part of the low grade meta-volcanic section, with the bulk consisting of subalkaline basalt, basaltic andesite, and shoshonite. Rb-Sr whole rock analyses of 7 basalts yield an age of 2687 +/- 54 Ma. This agrees well with an age of 2758 +/- 39 Ma from zircon U-Pb analyses of the interbedded rhyolites. Except for the allocthonous Imataca Complex of Venezuela, these dates for the Grao Para Group are the first well-constrained Archean ages from the Amazonian Craton. An even older age for the basement to the Grao Para Group is also implied. Sm-Nd whole-rock analyses of four of these basalts did not yield an isochron because of the limited range of /sup 147/Sm//sup 144/Nd values, but element of/sub Nd/ values relative to CHUR were calculated using the Rb-Sr age. The typical LREE-enrichment, lack of Ce depletion or spilitic alteration of alkalies, and the high Sr initial ratios, may indicate that these isotopic patterns were derived by incorporation of some older continental crust in the mafic melts. These data together with an element of/sub Sr/ of +63.6 might indicate significant seawater exchange with volcanic rocks derived from mantle with chondritic REE patterns. This demonstrates the presence of significant continental crust in the Archean and seawater-volcanic rock interaction in a rifting environment similar to modern analogs.

  16. Estudio fotométrico y espectroscópico de dos cúmulos abiertos jóvenes del disco con apariencia globular

    NASA Astrophysics Data System (ADS)

    Piatti, A. E.; Clariá, J. J.; Bica, E.

    Se presentan y discuten resultados obtenidos en el CASLEO y en el Observatorio de Las Campanas de dos cúmulos abiertos compactos con apariencia globular: Westerlund1 (BH197), ubicado en dirección hacia el centro galáctico, y Westerlund2. A partir de espectroscopía CCD integrada de ambos e imágenes CCD en las bandas VI obtenidas para el primero de ellos, se derivan sus parámetros fundamentales y se examinan sus apariencias estructurales. Se encuentra que Westerlund1 es un cúmulo joven (7 ± 3 millones de años), ubicado sobre el plano galáctico a 1.0 ± 0.4 kpc del sol, en una región caracterizada por una absorción excepcionalmente elevada (Av~=13.0 mag), en tanto que Westerlund2 es también un cúmulo joven (4-6 millones de años) ubicado sobre el plano, en una región afectada por una absorción menor (Av~=5.7 mag). Desde el punto de vista estructural, Westerlund 1 se presenta como uno de los pocos cúmulos abiertos jóvenes de la Galaxia con apariencia tipicamente globular, en contraste con los cúmulos azules de las Nubes de Magallanes en los cuales la apariencia globular constituye un fenómeno común. Westerlund2, aunque menos rico en estrellas, puede también ser incluído dentro de esta interesante clase de objetos.

  17. Techniques of remote sensing applied to the environmental analysis of part of an aquifer located in the São José dos Campos Region sp, Brazil.

    PubMed

    Bressan, Mariana Affonseca; Dos Anjos, Célio Eustáquio

    2003-05-01

    The anthropogenic activity on the surface can modify and introduce new mechanisms of recharging the groundwater system, modifying the tax, the frequency and the quality of recharge of underground waters. The understanding of these mechanisms and the correct evaluation of such modifications are fundamental in determining the vulnerability of groundwater contamination. The groundwater flow of the South Paraíba Compartment, in the region of São José dos Campos, São Paulo, is directly related to structural features of the Taubaté Basin and, therefore, the analysis of its behaviour enhances the understanding of tectonic structure. The methodology adopted for this work consists in pre-processing and processing of the satellite images, visual interpretation of HSI products, field work and data integration. The derivation of the main structural features was based on visual analysis of the texture elements of drainage, and the relief in sedimentary and crystalline rocks. Statistical analysis of the feature densities and the metric-geometric relations between the analysed elements have been conducted. The crystalline rocks, on which the sediments were laying, conditions and controls the structural arrangement of sedimentary formations. The formation of the South Paraíba Grabén is associated with Cenozoic distensive movement which reactivated old features of crust weakness and generated previous cycles with normal characteristics. The environmental analysis is based on the integration of the existing methodology to characterise vulnerability of an universal pollutant and density fracture zone. The digital integration was processed using GIS (Geographic Information System) to delineate five defined vulnerability classes. The hydrogeological settings were analysed in each thematic map and, using fuzzy logic, an index for each different vulnerability class was compiled. Evidence maps could be combined in a series of steps using map algebra.

  18. Diverging DOS strategy using an allene-containing tryptophan scaffold and a library design that maximizes biologically relevant chemical space while minimizing the number of compounds.

    PubMed

    Painter, Thomas O; Wang, Lirong; Majumder, Supriyo; Xie, Xiang-Qun; Brummond, Kay M

    2011-03-14

    A diverging diversity-oriented synthesis (DOS) strategy using an allene-containing tryptophan as a key starting material was investigated. An allene-yne substituted derivative of tryptophan 12 gave indolylmethylazabicyclooctadiene 17 when subjected to a microwave-assisted allenic [2 + 2] cycloaddition reaction. This same tryptophan-derived precursor afforded an indolylmethyldihydrocyclopentapyridinone 14 when subjected to a rhodium(I)-catalyzed cyclocarbonylation reaction and an indolylmethylpyrrolidinocyclopentenones 16 when reacted with molybdenum hexacarbonyl. Construction of allenic tetrahydro-β-carboline scaffolds via a Pictet-Spengler reaction and subsequent silver(I)-catalyzed cycloisomerization afforded tetrahydroindolizinoindoles (21). Attachment of allene and alkyne groups to the tetrahydro-β-carboline, followed by a microwave-assisted allenic [2 + 2] cycloaddition reaction, provided tetrahydrocyclobutaindoloquinolizinones 24 and the tetrahydrocyclopentenone indolizinoindolone 26 when reacted with molybdenum hexacarbonyl. These six scaffolds were used as templates for the construction of a virtual library of 11 748 compounds employing 44 indoles, 12 aldehydes, and 51 alkynes. Diversity analyses using a combination of cell-based chemistry space computations using BCUT (Burden (B) CAS (C) Pearlman at the University of Texas (UT)) metrics and Tanimoto coefficient (Tc) similarity calculations using two-dimensional (2D) fingerprints showed that the compounds in the virtual library occupied new chemical space when compared to the 327,000 compounds in the molecular libraries small molecule repository (MLSMR). A subset of fifty-three compounds was identified from the virtual library using the DVS package of Sybyl 8.0; this subset represents the most diverse compounds within the chemical space defined by these compounds and will be synthesized and screened for biological activity.

  19. Discovery of the base of the Pinal Schist and the Bear Canyon sequence below it in the eastern Metamorphic terrane of the Dos Cabezas mountains, Cochise County, Arizona

    SciTech Connect

    Erickson, R.C. . Geology Dept.)

    1993-04-01

    The eastern metamorphic terrane of the Dos Cabezas mountains is underlain by Pinal Schist (PS). Recent detailed mapping along the western edge of this terrane shows that a flat planar regional unconformity (UC) bounds this Pinal body at its western stratigraphic base. Below the UC lies 8 km[sup 2] of greenschist facies metapelites and metafelsites here given the provisional name of the Bear Canyon sequence (BCS). The PS above the UC is over 10 stratigraphic km, grading from 1 km conglomerate at the base (clasts are metafelsites and metasediments with very minor quartz and granite) up into 3 km of sandstones and then pelite, all with greenschist facies overprint. Relict bedding with abundant crossbedding is common; the sequence is upright. Foliation parallels bedding. Lineation is absent. The UC itself is well exposed in two places, on both sides of Happy Camp Canyon (HCC). On the west of HCC, the surface is exposed at the mouth of Bear Canyon (NW1/4 Sec. 31, T13S R28E) striking south and then southwest about 4 km, ending in the N center of Sec. 12, T14S R27E. The unconformity and the Pinal above it lie NS 30E in the north and smoothly swing to NE 50 SE in the south. Below the UC are 6 km[sup 2] of metasandstone and metafelsites of the BCS. The metasandstone is quartz-sericite schist with strong lineation ([minus]50 S70E) in its northern km of exposure. Bedding and foliation are NS 60 E in N, and NE 70 SE in S. This schist body is intruded on the E by a dike of quartz-phyric metafelsite to 1 km wide which underlies the UC along its entire length. The felsite shows strong relict flow layering and no foliation. Flow layering is NS 90 in the N, and strikes and dips variably in the S. A 1/4 km[sup 2] metafelsite plug intrudes the schist on the W, with flow layering NE 90. The two exposures of the UC are separated by a Precambrian normal fault striking N45E and dipping moderately SE under HCC alluvial fill; it has about a km of dip slip.

  20. Stratigraphy of fluvial sediment sequences and their palaeoenvironmental information in the foreland of the Serra dos Órgãos, southeastern Brazil

    NASA Astrophysics Data System (ADS)

    Kirchner, André; Nehren, Udo; Heinrich, Jürgen

    2013-04-01

    In the hinterland of Rio de Janeiro city the rivers Guapiaçu, Macacu and Iconha originate in the Serra dos Órgãos mountain range and drain into the Atlantic Ocean. Since their channelization in the 1950s, higher flow velocities caused an incision of the rivers into the valley fills. These circumstances provide the possibility to study the alluvial deposits along the streams during low water level and allow conclusions on palaeoenvironmental change and landscape history. Sedimentological investigations of 13 exposures as well as AMS 14C measurements were carried out to investigate sediment properties and reconstruct the sedimentation history within the floodplains. These results enable to distinguish three different facies units. A late Pleistocene Unit I can be detected at the base of the observed exposures and consists of clast-supported fine to coarse gravels. It can be assumed that the gravel bodies were formed by a climatically induced erosional-depositional cycle within a braided river system. The gravels are overlaid by Unit II, a grayish to bluish loam mainly of mid-Holocene age. During generally drier climates these loams have been deposited during high water stages or flooding events as a splay facies proximal to the rivers. A reduced flow competence and relatively stable morphodynamic conditions are assumed for that period. Unit III accumulated in the late Holocene typically consists of several meters of planar or cross bedded sands to fine gravels, interfingered by loamy inclusions, buried peat bogs and organic debris. Fining-upward sequences can be frequently studied within Unit III which were completed by loamy sediments in the uppermost parts of the exposures. The increased flow competence from Unit II to Unit III seems to be a fluvial response to the increased humidity of the late Holocene as well as the enhancement of El Niño-Southern Oscillation (ENSO). Heavy rainfall likely caused higher sediment supply from the steep slopes as well as a

  1. Geochemistry and petrogenesis of the Mesoarchean granites from the Canaã dos Carajás area, Carajás Province, Brazil: Implications for the origin of Archean granites

    NASA Astrophysics Data System (ADS)

    Feio, G. R. L.; Dall'Agnol, R.

    2012-12-01

    Four Mesoarchean (2.93 to 2.83 Ga) granite units, which encompass the Canaã dos Carajás, Bom Jesus, Cruzadão and Serra Dourada granites, were recognized in the Canaã dos Carajás area of the Archean Carajás Province. The Mesoarchean units are composed dominantly of biotite leucomonzogranites. They are compared with the Neoarchean Planalto suite (2.73 Ga) which encompasses biotite-hornblende monzogranites to syenogranites. The Canaã dos Carajás, Bom Jesus and the variety of the Cruzadão granite with higher (La/Yb)N are geochemically more akin to the calc-alkaline granites, whereas the other varieties of the Cruzadão granite are transitional between calc-alkaline and alkaline granites. The Serra Dourada granite has an ambiguous geochemical character with some features similar to those of calc-alkaline granites and other peraluminous granites. The Planalto granites have ferroan character, are similar geochemically to reduced A-type granites and show a strong geochemical contrast with the Mesoarchean studied granites. The Mesoarchean granites described in the Canaã dos Carajás area are geochemically distinct to those of the Rio Maria domain of the Carajás Province. The Canaã dos Carajás and Bom Jesus granites are similar to the high-Ca granites, whereas the Cruzadão and Serra Dourada are more akin to the low-CaO granites of the Yilgarn craton. The geochemical characteristics of the Mesoarchean studied granites approach those of the biotite granite group of Dharwar but the latter are enriched in HFSE and HREE compared to the Canaã dos Carajás granites. The Neoarchean Planalto suite granite has no counterpart in the Mesoarchean Rio Maria domain of the Carajás Province, neither in the Yilgarn and Dharwar cratons. Geochemical modeling suggests that partial melting of a source similar in composition to an Archean basaltic andesite of the Carajás Province could give origin to the Bom Jesus and Cruzadão granites. In the case of the Bom Jesus granite the

  2. Geochronological data from TTG-type rock associations of the Arroio dos Ratos Complex and implications for crustal evolution of southernmost Brazil in Paleoproterozoic times

    NASA Astrophysics Data System (ADS)

    Gregory, Tiago Rafael; Bitencourt, Maria de Fátima; Nardi, Lauro Valentim Stoll; Florisbal, Luana Moreira; Chemale, Farid, Jr.

    2015-01-01

    U-Pb isotope analyses by LA-MC-ICPMS (Laser Ablation - Multi Collector - Inductively Coupled Plasma Mass Spectrometry) in zircon crystals from metatonalites, tonalites and granodiorite gneiss from the Arroio dos Ratos Complex (ARC) early magmatism in southernmost Brazil are presented. The ARC is located in the eastern portion of the Sul-rio-grandense Shield, occurring as septa and roof pendants on granitoids emplaced along the Southern Brazilian Shear Belt (SBSB). The SBSB corresponds to a translithospheric structure composed of several anastomosed shear zones of dominantly transcurrent kinematics whose syntectonic magmatism, of Neoproterozoic age, is characteristic of post-collisional environments. The studied rocks comprise TTG-type associations with coeval mafic magmatism, deformed and metamorphosed within a ductile shear zone. Zircon crystals obtained from six samples are interpreted as igneous given that the crystals are subhedral to euhedral, bipyramidal, with concentric zonation, have ratios Th/U between 0.13 and 0.81 and have restricted evidence of overgrowth. The oldest Association 1 (A1) has structures compatible with recrystallization under conditions of high temperature and an igneous age of 2148 ± 33 Ma, obtained in a metatonalite. The rocks of Association 2 (A2) have similar compositions, although with a more significant coeval mafic fraction. They are intrusive into A1 and also show high-temperature recrystallization features. However, they are less deformed and partly preserve their primary, igneous fabric. The igneous ages obtained from two A2 tonalites are 2150 ± 28 Ma and 2136 ± 27 Ma. Association 3 (A3) is represented by tonalitic to granodioritic gneisses whose structure, composition and metamorphic features are similar to those of A1 rocks, except for the absence of coeval mafic magmas in the former. Local features resulting from partial melting are present in A3 rocks. Three samples from A3 were dated. A tonalitic gneiss gives igneous age

  3. Investigação dos perfís temporais de alta resolução de explosões solares tipo-III decimétricas

    NASA Astrophysics Data System (ADS)

    Cecatto, J. R.; Fernandes, F. C. R.; Sawant, H. S.; Madsen, F. R. H.

    2003-08-01

    Explosões solares tipo-III indicam a presença de feixes de elétrons acelerados durante "flares" solares. Sua investigação fornece informações tanto sobre os processos de aceleração de partículas quanto das características do agente causador e do local de aceleração. Explosões tipo-III decimétricas são geradas por feixes de elétrons viajando através de arcos magnéticos densos da baixa coroa solar. Os perfís temporais destes fenômenos, quando tomados com alta resolução, informam sobre os mecanismos de aceleração de partículas do feixe e o meio de transporte da energia liberada a partir da região de aceleração. Usando o Brazilian Solar Spectroscope (BSS), em operação no INPE, foram registradas dezenas de explosões tipo-III decimétricas, dentro da faixa de 2050-2250 MHz com alta resolução temporal (20 ms), em 13 de setembro de 2001, entre 13:00 e 16:10 UT. Foram selecionadas 10 explosões isoladas para uma investigação estatística detalhada de seus perfís temporais, em todos os cerca de 50 canais de freqüência. Os resultados indicam que cerca de 70% dos perfís temporais são complexos tanto durante a subida quanto descida. Os 30% restantes indicam que os perfís da subida podem ser bem representados, na maioria dos casos, por um processo não-linear e uma parcela significativa por processos lineares. Os perfís temporais da descida são dominados por um decaimento não-linear. Neste trabalho, será efetuada uma análise dos perfís temporais, tanto durante a subida quanto descida do fluxo, para as explosões selecionadas, em termos dos prováveis mecanismos de aceleração e relaxamento. 2

  4. Assessment of personnel absorbed dose at production of medical radioisotopes by a cyclotron.

    PubMed

    Sadat-Eshkevar, S M; Karimian, A; Mirzaee, M

    2011-09-01

    The medical radioisotope (201)Tl is produced by a cyclotron through the (203)Tl(p, 3n)(201)Pb reaction in the nuclear medicine research group of Agricultural, Medical and Industrial Research Schools in Iran. The produced (201)Pb decays to (201)Tl by electron capture. One of the most important problems that may occur is malfunction of a part of target or beam line, so that it needs the bombardment to be stopped and the problem fixed. In this work, induced radioactivity of the target, aluminium case of target, beam line and concrete walls of the thallium target room were calculated by Monte Carlo method. Then by using the results of the Monte Carlo simulation, the whole body absorbed dose to cyclotron personnel during repair and after stopping the bombardment, were assessed at different places of target room.

  5. Caffeine reduces dipyridamole-induced myocardial ischemia

    SciTech Connect

    Smits, P.; Aengevaeren, W.R.; Corstens, F.H.; Thien, T. )

    1989-10-01

    The mechanism of action of coronary vasodilation after dipyridamole may be based on inhibition of cellular uptake of circulating endogenous adenosine. Since caffeine has been reported to be a competitive antagonist of adenosine we studied the effect of caffeine on the outcome of dipiridamole-{sup 201}Tl cardiac imaging in one patient. During caffeine abstinence dipyridamole induced myocardial ischemia with down-slope ST depressions on the ECG, and reversible perfusion defects on the scintigrams. When the test was repeated 1 wk later on similar conditions, but now shortly after infusion of caffeine (4 mg/kg), the ECG showed nodepressions, and the scintigrams only slight signs of ischemia. We conclude that when caffeine abstinence is not sufficient, the widespread use of coffee and related products may be responsible for false-negative findings in dipyridamole-201Tl cardiac imaging.

  6. Myocardial accumulation of iodinated beta-methyl-branched fatty acid analogue, iodine-125-15-(p-iodophenyl)-3-(R,S)methylpentadecanoic acid (BMIPP), in relation to ATP concentration

    SciTech Connect

    Fujibayashi, Y.; Yonekura, Y.; Takemura, Y.; Wada, K.; Matsumoto, K.; Tamaki, N.; Yamamoto, K.; Konishi, J.; Yokoyama, A. )

    1990-11-01

    To clarify the relationship between the myocardial accumulation of {sup 125}I-15-(p-iodophenyl)-3-(R,S)-methylpentadecanoic acid (BMIPP) and intracellular adenosine-5'-triphosphate (ATP) content, the effect of 2,4-dinitrophenol (DNP, an electron transport uncoupler) on myocardial BMIPP accumulation was studied, in comparison with that of thallium-201-chloride ({sup 201}Tl-Cl). In the mouse myocardium, DNP decreased the intracellular ATP and ADP levels, without affecting either acyl-CoA synthetase activity or the level of CoA-SH. Following treatment with DNP, decreases in myocardial BMIPP accumulation correlated well with those of ATP, while {sup 201}Tl-Cl showed slightly increased accumulation in the myocardium. Thus, in some diseases, BMIPP may be useful in evaluating myocardial ATP levels.

  7. Noninvasive ergonovine maleate provocative testing for coronary artery spasm: the need for routine thallium-201 imaging

    SciTech Connect

    Shanes, J.G.; Krone, R.J.; Fisher, K.; Shah, B.; Eisenkramer, G.; Humphrey, J.R.

    1983-01-01

    We administered ergonovine and used both electrocardiographic monitoring and thallium-/sup 201/ (/sup 201/Tl) imaging to detect reversible ischemia in 100 patients. Patients already established as having coronary artery spasm and those with nonbypassed, proximal, high-grade coronary artery stenosis were excluded. No complication occurred in any patient. The use of thallium imaging in addition to electrocardiographic monitoring resulted in a higher degree of sensitivity than did ECG monitoring alone. Fourteen patients demonstrated evidence of coronary artery spasm as documented by /sup 201/Tl imaging but of the 14, significant ECG changes occurred in only 50%, and classic ST segment elevation in 21%. Thus, in carefully selected patients the noninvasive provocation of coronary spasm can be accomplished safely, but ECG monitoring must be combined with thallium-/sup 201/ imaging to achieve an acceptable degree of sensitivity.

  8. Abnormal thallium 201 scintigraphy during low-dose vasopressin infusions

    SciTech Connect

    Davison, R.; Kaplan, K.; Bines, A.; Spies, S.; Reed, M.T.; Lesch, M.

    1986-12-01

    Thallium 201 (/sup 201/Tl) myocardial scans were obtained in 16 patients just prior to the discontinuation of a vasopressin infusion (.1 to .2 units/min) administered for the treatment of upper gastrointestinal bleeding. Repeat scintigraphy was performed two to three hours after the vasopressin was stopped. Eleven of the 16 patients (69 percent) demonstrated areas of decreased myocardial /sup 201/Tl uptake that resolved after the infusion was stopped. Heart rate-blood pressure product was significantly lower at the time of the second scan. Autopsies were secured in three of 11 scan-positive patients: one had severe coronary artery obstruction, one nonsignificant disease, and another had normal coronary arteries. Vasopressin, even at low doses, can induce abnormalities in myocardial perfusion that are probably mediated by a direct effect on the coronary circulation. They are usually not detectable by routine monitoring techniques and conceivably form the basis for the cardiovascular morbidity associated with the use of this agent.

  9. Determinação de elementos próprios dos asteróides troianos: comparação entre as teorias semi-analítica e sintética

    NASA Astrophysics Data System (ADS)

    Roig, F.; Beaugé, C.

    2003-08-01

    Além do cálculo semi-analítico de elementos próprios dos asteróides Troianos (Beaugé & Roig 2001, Icarus 153, 391), recentemente foi apresentado um novo conjunto destes elementos próprios determinado através de uma teoria sintética (Knenezevic & Milani 2003, comunicação pessoal). As bases de dados contendo estas determinações estão disponiveis na pagina web do Asteroid Dynamical Site (http://hamilton.dm.unipi.it/cgi-bin/astdys/astibo). Nesta comunicação apresentamos os primeiros resultados de um estudo comparativo entre ambos conjuntos de elementos próprios, analisando suas vantagens e desvantagens, assim como os limites de precisão de cada conjunto. Mostramos que os elementos próprios sintéticos são mais precisos que os smi-analíticos para grandes amplitudes de libração do ângulo s = l-lJup, embora acontece o contrario para os corpos cuja amplitude de libração é muito pequena. Finalmente discutimos a influencia destes erros na determinação de familias de asteroides e da estrutura resonante em torno dos pontos Lagrangeanos L4 e L5.

  10. Characterization of a cAMP responsive transcription factor, Cmr (Rv1675c), in TB complex mycobacteria reveals overlap with the DosR (DevR) dormancy regulon

    PubMed Central

    Ranganathan, Sridevi; Bai, Guangchun; Lyubetskaya, Anna; Knapp, Gwendowlyn S.; Peterson, Matthew W.; Gazdik, Michaela; C. Gomes, Antonio L.; Galagan, James E.; McDonough, Kathleen A.

    2016-01-01

    Mycobacterium tuberculosis (Mtb) Cmr (Rv1675c) is a CRP/FNR family transcription factor known to be responsive to cAMP levels and during macrophage infections. However, Cmr's DNA binding properties, cellular targets and overall role in tuberculosis (TB) complex bacteria have not been characterized. In this study, we used experimental and computational approaches to characterize Cmr's DNA binding properties and identify a putative regulon. Cmr binds a 16-bp palindromic site that includes four highly conserved nucleotides that are required for DNA binding. A total of 368 binding sites, distributed in clusters among ∼200 binding regions throughout the Mycobacterium bovis BCG genome, were identified using ChIP-seq. One of the most enriched Cmr binding sites was located upstream of the cmr promoter, and we demonstrated that expression of cmr is autoregulated. cAMP affected Cmr binding at a subset of DNA loci in vivo and in vitro, including multiple sites adjacent to members of the DosR (DevR) dormancy regulon. Our findings of cooperative binding of Cmr to these DNA regions and the regulation by Cmr of the DosR-regulated virulence gene Rv2623 demonstrate the complexity of Cmr-mediated gene regulation and suggest a role for Cmr in the biology of persistent TB infection. PMID:26358810

  11. Radionuclide imaging in myocardial sarcoidosis. Demonstration of myocardial uptake of /sup 99m/Tc pyrophosphate and gallium

    SciTech Connect

    Forman, M.B.; Sandler, M.P.; Sacks, G.A.; Kronenberg, M.W.; Powers, T.A.

    1983-03-01

    A patient had severe congestive cardiomyopathy secondary to myocardial sarcoidosis. The clinical diagnosis was confirmed by radionuclide ventriculography, /sup 201/Tl, /sup 67/Ga, and /sup 99m/Tc pyrophosphate (TcPYP) scintigraphy. Myocardial TcPYP uptake has not been reported previously in sarcoidosis. In this patient, TcPYP was as useful as gallium scanning and thallium imaging in documenting the myocardial process.

  12. Effects of heart rate on myocardial thallium-201 uptake and clearance

    SciTech Connect

    Nordrehaug, J.E.; Danielsen, R.; Vik-Mo, H. )

    1989-12-01

    The effects of heart rate on the myocardial uptake and clearance of {sup 201}Tl were studied prospectively in seven healthy men, mean age 43 +/- 7 (s.d.) yr. Initial and delayed (3 hr) thallium images were obtained in three views after three bicycle exercise tests: to maximal, 80% and 60% of predicted maximal heart rate. The mean of three views initial myocardial {sup 201}Tl uptake was higher at maximal than at both 80% and 60% of predicted maximal heart rate, being 81% (p less than 0.01) and 60% (p less than 0.01) of maximal activity, respectively. The myocardial activity in the delayed images was identical. There was a linear relationship between heart rate and the initial myocardial activity, r = 0.86 (p less than 0.001). The mean (range) {sup 201}Tl clearance was 58% (51-65), 47% (34-56), and 34% (22-49) (all differences p less than 0.01), respectively. Concordance among the three individual views in estimating clearance was best for the highest exercise level. There was a linear relationship between heart rate and clearance, r = 0.80 (p less than 0.001). Clearance was altered by only 1.67 x 10%/heart bpm (0.024 hr/heart beat). Clearance in the liver, spleen and lungs increased at submaximal exercise levels. Thus, a linear relationship between heart rate and clearance is the result of changes in the initial exercise myocardial {sup 201}Tl activity. Submaximal exercise may reduce reproducibility of clearance estimation, and the change of myocardial clearance with heart rate seems less than previously suggested.

  13. Effects of CT-based attenuation correction of rat microSPECT images on relative myocardial perfusion and quantitative tracer uptake

    SciTech Connect

    Strydhorst, Jared H. Ruddy, Terrence D.; Wells, R. Glenn

    2015-04-15

    Purpose: Our goal in this work was to investigate the impact of CT-based attenuation correction on measurements of rat myocardial perfusion with {sup 99m}Tc and {sup 201}Tl single photon emission computed tomography (SPECT). Methods: Eight male Sprague-Dawley rats were injected with {sup 99m}Tc-tetrofosmin and scanned in a small animal pinhole SPECT/CT scanner. Scans were repeated weekly over a period of 5 weeks. Eight additional rats were injected with {sup 201}Tl and also scanned following a similar protocol. The images were reconstructed with and without attenuation correction, and the relative perfusion was analyzed with the commercial cardiac analysis software. The absolute uptake of {sup 99m}Tc in the heart was also quantified with and without attenuation correction. Results: For {sup 99m}Tc imaging, relative segmental perfusion changed by up to +2.1%/−1.8% as a result of attenuation correction. Relative changes of +3.6%/−1.0% were observed for the {sup 201}Tl images. Interscan and inter-rat reproducibilities of relative segmental perfusion were 2.7% and 3.9%, respectively, for the uncorrected {sup 99m}Tc scans, and 3.6% and 4.3%, respectively, for the {sup 201}Tl scans, and were not significantly affected by attenuation correction for either tracer. Attenuation correction also significantly increased the measured absolute uptake of tetrofosmin and significantly altered the relationship between the rat weight and tracer uptake. Conclusions: Our results show that attenuation correction has a small but statistically significant impact on the relative perfusion measurements in some segments of the heart and does not adversely affect reproducibility. Attenuation correction had a small but statistically significant impact on measured absolute tracer uptake.

  14. Prevalence and prognostic significance of exercise-induced silent myocardial ischemia detected by thallium scintigraphy and electrocardiography in asymptomatic volunteers

    SciTech Connect

    Fleg, J.L.; Gerstenblith, G.; Zonderman, A.B.; Becker, L.C.; Weisfeldt, M.L.; Costa, P.T. Jr.; Lakatta, E.G. )

    1990-02-01

    Although a silent ischemic electrocardiographic response to treadmill exercise in clinically healthy populations is associated with an increased likelihood of future coronary events (i.e., angina pectoris, myocardial infarction, or cardiac death), such a response has a low predictive value for future events because of the low prevalence of disease in asymptomatic populations. To examine whether detection of reduced regional perfusion by thallium scintigraphy improved the predictive value of exercise-induced ST segment depression, we performed maximal treadmill exercise electrocardiography (ECG) and thallium scintigraphy (201Tl) in 407 asymptomatic volunteers 40-96 years of age (mean = 60) from the Baltimore Longitudinal Study on Aging. The prevalence of exercise-induced silent ischemia, defined by concordant ST segment depression and a thallium perfusion defect, increased more than sevenfold from 2% in the fifth and sixth decades to 15% in the ninth decade. Over a mean follow-up period of 4.6 years, cardiac events developed in 9.8% of subjects and consisted of 20 cases of new angina pectoris, 13 myocardial infarctions, and seven deaths. Events occurred in 7% of individuals with both negative 201Tl and ECG, 8% of those with either test positive, and 48% of those in whom both tests were positive (p less than 0.001). By proportional hazards analysis, age, hypertension, exercise duration, and a concordant positive ECG and 201Tl result were independent predictors of coronary events. Furthermore, those with positive ECG and 201Tl had a 3.6-fold relative risk for subsequent coronary events, independent of conventional risk factors.

  15. Semiquantitative Analysis Using Thallium-201 SPECT for Differential Diagnosis Between Tumor Recurrence and Radiation Necrosis After Gamma Knife Surgery for Malignant Brain Tumors

    SciTech Connect

    Matsunaga, Shigeo; Shuto, Takashi; Takase, Hajime; Ohtake, Makoto; Tomura, Nagatsuki; Tanaka, Takahiro; Sonoda, Masaki

    2013-01-01

    Purpose: Semiquantitative analysis of thallium-201 chloride single photon emission computed tomography ({sup 201}Tl SPECT) was evaluated for the discrimination between recurrent brain tumor and delayed radiation necrosis after gamma knife surgery (GKS) for metastatic brain tumors and high-grade gliomas. Methods and Materials: The medical records were reviewed of 75 patients, including 48 patients with metastatic brain tumor and 27 patients with high-grade glioma who underwent GKS in our institution, and had suspected tumor recurrence or radiation necrosis on follow-up neuroimaging and deteriorating clinical status after GKS. Analysis of {sup 201}Tl SPECT data used the early ratio (ER) and the delayed ratio (DR) calculated as tumor/normal average counts on the early and delayed images, and the retention index (RI) as the ratio of DR to ER. Results: A total of 107 tumors were analyzed with {sup 201}Tl SPECT. Nineteen lesions were removed surgically and histological diagnoses established, and the other lesions were evaluated with follow-up clinical and neuroimaging examinations after GKS. The final diagnosis was considered to be recurrent tumor in 65 lesions and radiation necrosis in 42 lesions. Semiquantitative analysis demonstrated significant differences in DR (P=.002) and RI (P<.0001), but not in ER (P=.372), between the tumor recurrence and radiation necrosis groups, and no significant differences between metastatic brain tumors and high-grade gliomas in all indices (P=.926 for ER, P=.263 for DR, and P=.826 for RI). Receiver operating characteristics analysis indicated that RI was the most informative index with the optimum threshold of 0.775, which provided 82.8% sensitivity, 83.7% specificity, and 82.8% accuracy. Conclusions: Semiquantitative analysis of {sup 201}Tl SPECT provides useful information for the differentiation between tumor recurrence and radiation necrosis in metastatic brain tumors and high-grade gliomas after GKS, and the RI may be the most

  16. Detection of right ventricular pressure overloading by thallium-201 myocardial scintigraphy. Results in 57 patients with chronic respiratory diseases

    SciTech Connect

    Weitzenblum, E.; Moyses, B.; Dickele, M.C.; Methlin, G.

    1984-02-01

    The diagnostic value of thallium 201 (/sup 201/Tl) myocardial imaging was studied in 57 patients with chronic respiratory diseases, most with COPD (n . 46), by comparing the results to hemodynamic findings. In healthy subjects, the right ventricle (RV) is not visualized; therefore, any recorded activity of the RV was considered as indicating RV hypertrophy due to RV pressure overloading (RVPO). RV activity was graded from 0 (no activity) to 3 (activity greater than or equal to that of the left ventricle). Patients were divided into three groups according to the level of the pulmonary artery mean pressure (PPA): PPA less than or equal to 20 mm Hg (no pulmonary arterial hypertension (PAH) ) . group 1, n . 20; PPA ranging from 21 to 30 mm Hg (mild to moderate PAH) . group 2, n . 20; PPA greater than 30 mm Hg (marked PAH) . group 3, n . 17. RV was visualized in 14 patients in group 3 (82 percent) and in 13 patients in group 2 (65 percent). For all patients with PAH (2 + 3) the sensitivity of /sup 201/Tl imaging for the diagnosis of RVPO was of 73 percent, higher than that of ECG and echocardiography (both 51 percent). The sensitivity of /sup 201/Tl, even if moderate (65 percent) was better than that of ECG (30 percent) or echo (40 percent) in patients with mild-to-moderate PAH (group 2). A high RV activity (grade 3) was observed in only three patients. The specificity of this method (obtained from results in group 1) was of 80 percent vs 89 percent for echo and 100 percent for ECG. These results suggest that 201Tl myocardial imaging is a rather sensitive method and could be of interest for the noninvasive diagnosis of RVPO in COPD patients.

  17. Effects of asymmetric photopeak windows on flood field uniformity and spatial resolution of scintillation cameras.

    PubMed

    Graham, L S; LaFontaine, R L; Stein, M A

    1986-05-01

    Pulse height analyzer windows that are set on the high side of the photopeak are known to improve spatial resolution and contrast when used for scintillation camera imaging. Asymmetric windows can be used with some scintillation cameras that have energy correction circuitry. In this study the improvement in spatial resolution and loss of field uniformity for 99mTc, 201Tl, and 131I were measured as a function of window asymmetry (up to 30%, defined relative to the loss of counts as compared to a symmetric window under intrinsic conditions). Flood field uniformity was inversely related to the degree of window asymmetry. With 10 cm of scatter the 99mTc integral uniformity deteriorated from 7.9% with a symmetric window to 11.5% for a 30% asymmetric window. The corresponding values for 201Tl were 9.9 and 10.9%. Even without additional scatter, the values for 131I were 23.0 and 26.5%. Spatial resolution, as measured by the full width at half maximum in 10 cm of scatter improved by only 5% for 99mTc and 7% for 201Tl. However, the full width at tenth maximum increased by as much as 20% for 99mTc and 201Tl. A large percentage of this improvement was attained with small degrees of asymmetry. This study demonstrates that 10% or less asymmetry can provide most of the benefit in spatial resolution and contrast that is to be gained without significant losses in field uniformity and count rate.

  18. Estimation of infarct size by myocardial emission computed tomography with thallium-201 and its relation to creatine kinase-MB release after myocardial infarction in man

    SciTech Connect

    Tamaki, S.; Nakajima, H.; Murakami, T.

    1982-11-01

    Emission computed tomography (ECT) for thallium-201 (/sup 201/Tl) myocardial imaging was evaluated in estimating infarct size (IS). In 18 patients in whom IS was estimated enzymatically at the time of the acute episode, planar /sup 201/Tl perfusion scintigraphy and ECT with a rotating gamma camera were performed 4 weeks after the first myocardial infarction. From the size of /sup 201/Tl perfusion defects, the infarct area in planar images and the infarct volume in reconsturcted ECT images were measured by computerized planimetry. When scintigraphic IS was compared with the accumulated creatine kinase-MB isoenzyme release (CK-MBr), infarct volume determined from ECT correlated closely with CK-MBr (r=0.89), whereas infarct area measured from planar images correlated less satisfactorily with the enzymatic IS (for an average infarct area from three views, r=0.69; for the largest infarct area, r=0.73). Although conventional scintigraphic evaluation is useful for detecting and localizing infarction, quantification of ischemic injury with this two-dimensional technique has a significant inherent limitation. The ECT approach can provide a more accurate three-dimensional quantitative estimate of infarction, and can corroborate the enzymatic estimate of IS.

  19. Imaging of cocaine-induced global and regional myocardial ischemia

    SciTech Connect

    Oster, Z.H.; Som, P.; Wang, G.J.; Weber, D.A. )

    1991-08-01

    Severe and often fatal cardiac complications have been reported in cocaine users with narrowed coronary arteries caused by atherosclerosis as well as in young adults with normal coronaries. The authors have found that in normal dogs cocaine induces severe temporary hypoperfusion of the left ventricle as indicated by a significantly lower 201Tl concentration compared to the baseline state. The most significant decrease in uptake occurred 5 min after injection and was more pronounced in the septal and apical segments. Following intravenous administration of cocaine, instead of gradual disappearance of 201Tl from the left ventricle, there was continuous increase in 201Tl concentration in the left ventricle. These imaging experiments indicate that the deleterious effects of cocaine on the heart are probably due to spasm of the coronaries and decreased myocardial perfusion. Since spasm of the large subpericardial vessels does not seem to explain the magnitude of the increased coronary resistance and decreased coronary flow after cocaine as described in the literature, it is suggested that microvascular spasm of smaller vessels plays a major role in the temporary decrease in perfusion. The data may also suggest that severe temporary myocardial ischemia is probably the initiating factor for the cardiac complications induced by cocaine.

  20. Dobutamine stress-redistribution-reinjection versus rest-redistribution thallium-201 SPECT in the assessment of myocardial viability.

    PubMed

    Cornel, J H; Bax, J J; Elhendy, A; Reijs, A E; Fioretti, P M

    1997-02-01

    The aim of this study was to evaluate the value of thallium-201 chloride (201Tl) reinjection imaging following dobutamine stress (DRi) to identify viable myocardium in comparison with a rest-redistribution 201Tl protocol (RR). The identification of viable myocardium bears important consequences for adequate selection of patients with poor left ventricular function, often unable to exercise, who are considered for revascularization. Twenty-six patients with chronic coronary artery disease and depressed left ventricular function (ejection fraction 36 +/- 10%) were studied by both DRi and RR single photon emission computed tomography (SPECT). Semi-quantitative analysis of regional 201Tl activity (5-point score) and wall motion by echocardiography using a 16-segment model was performed. Regions were classified as viable (normal/reversible/fixed moderate defects) or non-viable (fixed severe defects) and related to regional wall motion. Target heart rate was reached in 25 patients. Myocardial viability was demonstrated in 353/416 (85%) by DRi SPECT and in 346/416 (83%) by RR SPECT. The agreement between the 2 protocols was 98% with a K-value of 0.94; similar results were obtained when the analysis was limited to dyscontractile segments. In conclusion, this study demonstrates the feasibility and diagnostic value of DRi SPECT to identify viable myocardium.

  1. The comparison of 2-18F-2-deoxyglucose and 15-(ortho-123I-phenyl)-pentadecanoic acid uptake in persisting defects on thallium-201 tomography in myocardial infarction

    SciTech Connect

    Henrich, M.M.; Vester, E.; von der Lohe, E.; Herzog, H.; Simon, H.; Kuikka, J.T.; Feinendegen, L.E. )

    1991-07-01

    The myocardial uptake of glucose and fatty acids into 201Tl redistribution defects were studied in 32 patients with myocardial infarction by tomography using 2-18F-2-deoxyglucose (FDG) and 15-(ortho-123I-phenyl)-pentadecanoic acid (oPPA). A total of 1153 segments were analyzed, 408 (35%) of which showed a persistent thallium-defect in stress-redistribution images. Of the segments with a decreased 201Tl uptake in these redistribution tomograms, 50.5% had a decreased uptake of both FDG and oPPA; in 21.8% FDG as well as oPPA uptake was within normal range. Normal FDG uptake but decreased oPPA uptake was detected in 17.4%, whereas 10.3% of the segments had normal oPPA uptake but decreased FDG uptake (chi-square test, p less than 0.001). A significant correlation of FDG and oPPA uptake (r = 0.51) was found in the segments with persistent 201Tl defect. Thus, a substantial fraction of persistent thallium-defects after healed myocardial infarction exhibit FDG as well as oPPA uptake, probably due to residual fatty acid metabolism in partially ischemic regions.

  2. Tomographic thallium-201 myocardial perfusion scintigrams after maximal coronary artery vasodilation with intravenous dipyridamole: comparison of qualitative and quantitative approaches

    SciTech Connect

    Francisco, D.A.; Collins, S.M.; Go, R.T.; Ehrhardt, J.C.; Van Kirk, O.C.; Marcus, M.L.

    1982-08-01

    Eighty-six patients had thallium-201 (/sup 201/Tl) myocardial perfusion scintigrams after intense coronary artery dilation with i.v. dipyridamole. Tomographic and planar /sup 201/Tl scintigrams were obtained in each patient. Tomographic scintigrams were interpreted using quantitative or visual criteria; planar scintigrams were assessed using visual criteria only. When visual criteria were used, interobserver variability was 40% for tomographic scintigrams and 44% for planar scintigrams. In the 24 patients with normal or nonsignificant CAD, quantitative analysis of the tomograms (range approach) indicated that one of 24 (4%) had a positive image (specificity 96%%); in contrast, when visual criteria were used to interpret the tomographic or planar /sup 201/Tl scintigrams, eight of 24 (33%) had positive scintigrams (specificity 67%). In the 51 abnormal patients, the sensitivity of detecting CAD was 46 of 51 (90%) for tomographic scintigrams interpreted quantitatively, 39 of 51 (76%) for tomographic scintigrams interpreted visually and 41 of 51 (80%) for planar scintigrams assessed visually. The tomographic imaging procedure (quantitative interpretation) also demonstrated a high sensitivity (89%) and specificity (100%) in 28 patients (10 normal and 18 CAD), with a clinical diagnosis of unstable angina pectoris. Overall, the predictive accuracy of an abnormal scintigram with quantitative tomographic imaging (98%) was significantly better (p<0.05) than either qualitative planar or pinhole imaging. (JMT)

  3. Thallium-201 brain tumor imaging: a comparative study with pathologic correlation

    SciTech Connect

    Kaplan, W.D.; Takvorian, T.; Morris, J.H.; Rumbaugh, C.L.; Connolly, B.T.; Atkins, H.L.

    1987-01-01

    In patients with gliomas who were stable or improving, we noted a disparity between clinical status and computed tomography (CT) brain scan results. To elucidate this finding, 29 patients were sequentially scanned with 2.0 mCi of /sup 201/Tl (5-30 min), 20 mCi (/sup 99m/Tc)gluceptate (GH) (3-4 hr) and 7-10 mCi 67Ga (48-72 hr). A total of 198 images were obtained. A set of three scans at a midpoint in follow up was selected for analysis. Seven patients who died had neuropathologic data available; brain sections were reconstructed to match radionuclide views without knowledge of image results. In the seven patients with autopsy data, /sup 201/Tl offered the most accurate correlation with viable tumor. Gallium-67 gave similar results in patients not receiving steroids. Technetium-99m GH scans could not allow differentiation between tumor, necrosis, and edema. Similarly, the CT scan could not routinely differentiate between fibrotic, nonfibrotic, necrotic, and neoplastic tissue. In the 22 patients without autopsy data, /sup 201/Tl scans commonly showed smaller and more focal abnormal uptake when compared with (/sup 99m/Tc)GH and /sup 67/Ga scans. Thallium-201 scans more accurately reflect viable tumor burden than other radionuclide studies of primary brain tumors, are minimally affected by concomitant steroid administration, can be performed immediately following tracer administration, and complement the anatomic data obtained from CT scans.

  4. Factores socio-económicos asociados a la percepción de situación socioeconómica entre adultos mayores de dos países latinoamericanos

    PubMed Central

    Brenes-Camacho, Gilbert

    2014-01-01

    El objetivo principal del artículo es estudiar la asociación entre la percepción subjetiva sobre la situación económica propia y una serie de medidas objetivas de bienestar socioeconómico –fuentes de ingresos, tenencia de vivienda, nivel educativo y transferencias familiares informales de dinero- entre adultos mayores de dos países Latinoamericanos: México y Costa Rica. Los datos se obtienen de las primeras rondas de dos encuestas sobre envejecimiento: CRELES para Costa Rica y ENASEM para México. La variable dependiente más importante se obtiene de las respuestas a las pregunta “¿Cómo califica su situación económica actual?” en Costa Rica y “¿Diría usted que su situación económica es…?” en México. Para ambas encuestas, las respuestas se codificaron en forma binaria; el código 0 representa las categorías Excelente, Muy buena y Buena, y el código 1 representa a las categorías Regular y Mala. Se encontró que el ingreso por jubilación es un importante determinante de la percepción de bienestar en ambos países. En Costa Rica, el ingreso del cónyuge y la tenencia de vivienda son importantes predictores de la percepción de bienestar, mientras que en México, los ingresos por transferencias están fuertemente asociados con dicha percepción. PMID:25360057

  5. Identificabilidade e estabilidade dos parâmetros no método Grade of Membership (GoM): considerações metodológicas e práticas

    PubMed Central

    Guedes, Gilvan Ramalho; Caetano, André Junqueira; Machado, Carla Jorge; Brondízio, Eduardo Sonewend

    2011-01-01

    O método Grade of Membership (GoM) tem sido cada vez mais utilizado por demógrafos brasileiros e tem a vantagem de possuir um parâmetro que mensura a heterogeneidade individual, com base nas correlações não-observáveis entre as categorias de resposta das variáveis de interesse, gerando um medida do grau de pertencimento de cada indivíduo a perfis extremos. Alguns autores, contudo, chamam atenção para questões importantes na calibragem dos modelos finais que utilizam o programa GoM versão 3.4, como o problema de identificabilidade – soluções múltiplas para parâmetros estimados. Neste artigo, é sugerido um procedimento capaz de identificar um modelo final com solução única que descreva os tipos puros mais fidedignos à base de dados, em uma tentativa de otimização. Para ilustrar esse processo, utilizou-se uma base de dados correspondente a um levantamento econômico e sociodemográfico de uma população de pequenos agricultores residentes ao longo da Rodovia Transamazônica, no Estado do Pará. Também identificou-se a existência de instabilidade nos parâmetros estimados pelo programa GoM 3.4, sendo proposto um método de estabilização de seus valores. Com esses procedimentos combinados, os usuários do programa GoM 3.4 poderão descrever sua base de dados de forma mais adequada e responder às críticas sobre questões de identificabilidade e estabilidade dos modelos resultantes. Essas soluções empíricas são relevantes por afetarem cálculos de prevalência e de incidência de eventos de interesse, além de trazerem consequências importantes sobre o ponto e o momento corretos para intervenções de políticas públicas ou de planejamento prospectivo em análises de projeção. PMID:21709732

  6. Tritium ((3)H) as a tracer for monitoring the dispersion of conservative radionuclides discharged by the Angra dos Reis nuclear power plants in the Piraquara de Fora Bay, Brazil.

    PubMed

    de Carvalho Gomes, Franciane; Godoy, José Marcus; de Carvalho, Zenildo Lara; de Souza, Elder Magalhães; Rodrigues Silva, José Ivan; Tadeu Lopes, Ricardo

    2014-10-01

    Presently, two nuclear power plants operate in Brazil. Both are located at Itaorna beach, Angra dos Reis, approximately 133 km from Rio de Janeiro city. The reactor cooling circuits require the input of seawater, which is later discharged through a pipeline into the adjacent Piraquara de Fora Cove. The radioactive effluents undergo ion-exchange treatment prior to their release in batches, causing the enrichment of (3)H relative to other radionuclides in the discharged waters. Under steady state conditions, the (3)H gradient in the Piraquara de Fora waters can be used to determine the dependence of the dilution factor on the distance from the discharge point. The present work describes experiments carried out at the reactor site during batch release episodes, including time series sampling at the discharge point and surface seawater sampling every 250 m to a distance of 1250 m, after a double distillation, the (3)H concentration was measured by liquid scintillation counting applying a Quantulus liquid scintillation spectrometer. The obtained results showed a linear relationship between the (3)H concentration and distance from the discharge point. At 1250 m from the discharge point a dilution index of 1:15 was measured which fits the expected value based on modeling.

  7. DOS/Russian - US program overview

    SciTech Connect

    Pifer, M.L.

    1996-04-01

    This paper describes the organization and describes the objectives for the science and technology agreements between the U.S.A. and Russia. The Gore-Chernomyrdin Commission objectives and the Civilian Research and the Development Foundation for the Independent States of the former Soviet Union (CRDF) are discussed.

  8. 27 CFR 9.175 - Dos Rios.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... contour line and Poonkinny Road, proceed southerly and then easterly along the meandering 2,000-foot contour line to its intersection with the eastern boundary of section 2, T21N, R13W, immediately south of... then westerly along the meandering 2,000-foot contour line, crossing Big Water Canyon, Doghouse...

  9. 27 CFR 9.175 - Dos Rios.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... contour line and Poonkinny Road, proceed southerly and then easterly along the meandering 2,000-foot contour line to its intersection with the eastern boundary of section 2, T21N, R13W, immediately south of... then westerly along the meandering 2,000-foot contour line, crossing Big Water Canyon, Doghouse...

  10. 27 CFR 9.175 - Dos Rios.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... contour line and Poonkinny Road, proceed southerly and then easterly along the meandering 2,000-foot contour line to its intersection with the eastern boundary of section 2, T21N, R13W, immediately south of... then westerly along the meandering 2,000-foot contour line, crossing Big Water Canyon, Doghouse...

  11. 27 CFR 9.175 - Dos Rios.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... contour line and Poonkinny Road, proceed southerly and then easterly along the meandering 2,000-foot contour line to its intersection with the eastern boundary of section 2, T21N, R13W, immediately south of... then westerly along the meandering 2,000-foot contour line, crossing Big Water Canyon, Doghouse...

  12. Scheduling Software for MS-DOS Microcomputers.

    ERIC Educational Resources Information Center

    Carlson, David H.; Prior, Barbara

    1991-01-01

    Identifies four microcomputer-based software packages for scheduling and evaluates their usefulness for scheduling employees in a library setting. Evaluation criteria are applied to (1) Schedule Master, from Schedule Master Corporation; (2) Schedule Plus, from Cyclesoft, Inc.; (3) Who Works When, from Newport Systems; and (4) Working Hours, from…

  13. Molecular Characterization of Human Pathogenic Bunyaviruses of the Nyando and Bwamba/Pongola Virus Groups Leads to the Genetic Identification of Mojuí dos Campos and Kaeng Khoi Virus

    PubMed Central

    Groseth, Allison; Mampilli, Veena; Weisend, Carla; Dahlstrom, Eric; Porcella, Stephen F.; Russell, Brandy J.; Tesh, Robert B.; Ebihara, Hideki

    2014-01-01

    Background Human infection with Bwamba virus (BWAV) and the closely related Pongola virus (PGAV), as well as Nyando virus (NDV), are important causes of febrile illness in Africa. However, despite seroprevalence studies that indicate high rates of infection in many countries, these viruses remain relatively unknown and unstudied. In addition, a number of unclassified bunyaviruses have been isolated over the years often with uncertain relationships to human disease. Methodology/Principal Findings In order to better understand the genetic and evolutionary relationships among orthobunyaviruses associated with human disease, we have sequenced the complete genomes for all 3 segments of multiple strains of BWAV (n = 2), PGAV (n = 2) and NDV (n = 4), as well as the previously unclassified Mojuí dos Campos (MDCV) and Kaeng Khoi viruses (KKV). Based on phylogenetic analysis, we show that these viruses populate 2 distinct branches, one made up of BWAV and PGAV and the other composed of NDV, MDCV and KKV. Interestingly, the NDV strains analyzed form two distinct clades which differed by >10% on the amino acid level across all protein products. In addition, the assignment of two bat-associated bunyaviruses into the NDV group, which is clearly associated with mosquito-borne infection, led us to analyze the ability of these different viruses to grow in bat (RE05 and Tb 1 Lu) and mosquito (C6/36) cell lines, and indeed all the viruses tested were capable of efficient growth in these cell types. Conclusions/Significance On the basis of our analyses, it is proposed to reclassify the NDV strains ERET147 and YM176-66 as a new virus species. Further, our analysis definitively identifies the previously unclassified bunyaviruses MDCV and KKV as distinct species within the NDV group and suggests that these viruses may have a broader host range than is currently appreciated. PMID:25188437

  14. Impact of natural climate change and historical land use on vegetation cover and geomorphological process dynamics in the Serra dos Órgãos mountain range in Rio de Janeiro State, Brazil

    NASA Astrophysics Data System (ADS)

    Nehren, U.; Sattler, D.; Heinrich, J.

    2010-03-01

    The Serra dos Órgãos mountain range in the hinterland of Rio de Janeiro contains extensive remnants of the Atlantic Forest (Mata Atlântica) biome, which once covered about 1.5 million km² from Northeast to South Brazil and further inland to Paraguay and Argentina. As a result of historical deforestation and recent land use intensification processes today only 5 to 8% of the original Atlantic Forest remains. Despite the dramatic habitat loss and a high degree of forest fragmentation, the remnants are among the Earth’s most diverse habitats in terms of species richness. Furthermore, they are characterized by a high level of endemism. Therefore, the biome is considered a "hotspot of biodiversity". In the last years many efforts have been taken to investigate the Mata Atlântica biome in different spatial and time scales and from different scientific perspectives. We are working in the Atlantic Forest of Rio de Janeiro since 2004 and focus in our research particularly on Quaternary landscape evolution and landscape history. By means of landscape and soil archives we reconstruct changes in the landscape system, which are mainly the result of Quaternary climate variability, young tectonic uplift and human impact. The findings throw light on paleoecological conditions in the Late Quaternary and the impact of pre-colonial and colonial land use practices on these landscapes. In this context, a main focus is set on climate and human-driven changes of the vegetation cover and its consequences for the geomorphological process dynamics, in particular erosion and sedimentation processes. Research methods include geomorphological field studies, interpretation of satellite images, physical and chemical sediment and soil analyses as well as relative and absolute dating (Feo/Fed ratio and 14C dating). For the Late Quaternary landscape evolution, the findings are compared with results from paleoclimatic and paloecological investigations in Southeast and South Brazil using other

  15. ANÁLISE DA INSERÇÃO DOS TEMAS DE HUMANIDADES E ÉTICA, COM METODOLOGIA DE APRENDIZAGEM BASEADA EM PROBLEMAS, EM CURRICULO MÉDICO INTEGRADO EM ESCOLA PÚBLICA NO DISTRITO FEDERAL, BRASIL

    PubMed Central

    Novaes, Maria Rita Carvalho Garbi; Novaes, Luiz Carlos Garcez; Guilhem, Dirce; Lolas, Fernando; Silveira, Carla; Guiotti, Murilo

    2009-01-01

    Objetivo Realizar uma análise da inserção da ética e humanidades no currículo do Curso de Medicina da Escola Superior em Ciências da Saúde - ESCS, escola pública do Distrito Federal, Brasil, de forma a contribuir com o processo de gestão curricular. Metodologia O Estudo é de coorte e documental. Foram pesquisados 37 termos relacionados à ética e 36 referentes à humanização nos objetivos educacionais e conteúdo dos módulos temáticos, habilidades e atitudes e interação ensino-serviço-comunidade, de 1a a 4a série e no programa do internato no currículo (ano 2006) e no projeto pedagógico do Curso de Medicina (2001). Resultados Maior inserção da humanização, ética e bioética na 1a e 2a série, quando comparado à inserção na 3a e 4a série e no internato, (IC95%-α=0,034, pvalue=0,007). Unidade de habilidades e atitudes: freqüência das 3 temáticas no currículo da 1a a 4a séries (IC95%-α=0,026, pvalue=0,013). Quando comparada a inserção entre o internato e as quatro primeiras séries, observa-se que nestas a inserção da temática humanização é superior (IC95%-α=0,042, pvalue=0,029). Conclusão O currículo desenvolvido no ano de 2006 na ESCS apresentou correlação com o projeto pedagógico do curso e contemplou a temática de forma abrangente, em todas as séries e internato. PMID:20396594

  16. [Identification of viable myocardium in ischemic heart disease with severe left ventricular contractile dysfunction: comparison of myocardial scintigraphy with 99mTc-sestamabi and with 201-thallium].

    PubMed

    Brandao, S; Cagnac, R; Roncalli, J; Lotterie, J A; Elbaz, M; Richez, F; Galinier, M; Carrie, D; Alibelli-Chemarin, M J

    2005-06-01

    The aim of this study was to compare quantitatively uptake of 99mTc-Sestamibi at rest and that of late redistribution of 201Tl in the same patients with severe ischaemic left ventricular dysfunction, and to correlate the uptake of the tracer to regional ventricular dysfunction studied by ECG grated 99Tc-Sestamini. A double isotope myocardial scintigraphy, 201 Thallium at rest/redistribution and 99Tc-Sestamibi at rest and on exercise, was performed in 28 patients with severe postinfarction ischaemic cardiomyopathy (EF= 29 +/- 4%). Quantitative analysis for each patient and each isotope were performed with respect to the number of hits expressed in percentage of the activity of a normal zone in 17 circumferential profiles distributed in 4 zones, that is to say in 476 segments. A score allowed counting of viable and non-viable segments and evaluation of contractile function of the 17 segments with respect to wall motion and systolic thickening. Total concordance of global uptake of the two isotopes was observed in 430 of the 476 segments (90.3%) (r= 0.814, p< 0.0001), but the 99mTc-Sestamibi uptake was less than 201 Th (71 +/- 23% vs 73 +/- 21%, p= 0.0001). With respect to left ventricular wall motion, uptake of 99mTc-Sestamibi was greater than that of 201Tl in normal or hypokinetic segments but less in akinetic and dyskinetic segments. The difference between the two isotopes was most marked in segments with very severe contractile dysfunction. The authors conclude that the uptake of 99mTc-Sestamibi is correlated with that of late distribution of 201Tl when left ventricular contraction is not too poor and should no longer be considered as only a marker of perfusion but can also be useful in the investigation of myocardial viability.

  17. Phantom evaluation of simultaneous thallium-201/technetium-99m aquisition in single-photon emission tomography.

    PubMed

    Cao, Z; Chen, C C; Maunoury, C; Holder, L E; Abraham, T C; Tehan, A

    1996-11-01

    This study investigated downscatter effects in cardiac single-photon emission tomographic studies with simultaneous thallium-201/technetium-99m acquisition, and evaluated a previously proposed subtraction technique for downscatter compensation. Ten studies were carried out with different defect sizes and locations and varying activity distributions using four energy windows: 70+/-10% keV, 140+/-10% keV, 100+/-10% KeV, and 103+/-16% keV. The subtraction technique used the 100- or 103-keV data to remove scattered 99mTc counts from the 70-keV data. The size and contrast of infarcts in the dual-isotope 70-keV image were artificially decreased compared to those in the 140-keV image, caused by scattered 99mTc counts that were comparable to the primary 201Tl counts in the 70-keV window. The subtraction technique produced larger defects and more heterogeneous activity in the myocardial wall in dual-isotope 70-keV images compared to the corresponding 201Tl-only images. These artifacts were caused by the markedly different spatial distributions of scattered 99mTc counts in the 100-keV (or 103-keV) window as compared with the 70-keV window. It is concluded that scattered 99mTc photons may cause overestimation of ischemia and myocardial viability in simultaneous dual-isotope patient studies. The proposed subtraction technique was inaccurate and produced image artifacts. Adequate downscatter compensation methods must be developed before applying simultaneous 201Tl/99mTc acquisition in clinical practice.

  18. Contribution of different scintigraphic techniques to the management of medullary thyroid carcinoma

    SciTech Connect

    Sandrock, D.; Blossey, H.C.; Steinroeder, M.; Munz, D.L.

    1989-01-01

    We compared three different scintigraphic techniques for the localization of neck recurrences and metastases in seven patients with medullary thyroid carcinoma one month to eight years after the first surgical intervention. Three successive scintigraphic studies were performed in five patients (6 x 3 studies) within two weeks using 201Tl chloride, 111In-labeled F(ab')2 fragments of the anti-carcinoembryonic antigen (anti-CEA) monoclonal antibody (MoAb) BW 431/31, and 131I meta-iodo-benzylguanidine (MIBG). Additionally, 11 studies were performed with the 111In-labeled MoAb fragment BW 431/31 (seven studies) or the 99mTc-labeled intact anti-CEA MoAb BW 431/26 (four studies). The gold standards for classifying scintigraphic results were biopsy, histology, surgery, and cytology. Six regions were classified as positive or negative in each study: thyroid region, four quadrants (lymph node regions) around the thyroid, and the region of the upper mediastinum. Of 36 sites, 201Tl was true positive (TP) in seven sites, false-positive (FP) in one site, true negative (TN) in 22 sites, and false-negative (FN) in six sites, resulting in a sensitivity of 54% and a specificity of 96%. 131I MIBG was TP in four sites, FP in none of the sites, TN in 23 sites, and FN in nine sites, with a sensitivity of 31% and a specificity of 100%. Immunoscintigraphy (102 sites overall) was TP in 16 sites, FP in five sites, TN in 77 sites, and FN in four sites, resulting in a sensitivity of 80% and a specificity of 94%. Immunoscintigraphy with 111In/99mTc anti-CEA F(ab')2 fragment/intact antibody is superior to scintigraphy with 201Tl and 131I MIBG.

  19. Comparison of the activity measurements in nuclear medicine services in the Brazilian northeast region.

    PubMed

    de Farias Fragoso, Maria da Conceição; de Albuquerque, Antônio Morais; de Oliveira, Mércia L; de Lima, Fabiana Farias; Barreto, Flávio Chiappetta Paes; de Andrade Lima, Ricardo

    2013-12-01

    The Northeastern Regional Centre for Nuclear Sciences (CRCN-NE), National Nuclear Energy Commission, has organized for the first time in nuclear medicine services (NMSs) in the Brazilian northeast region a comparison of activity measurements for (99m)Tc, (131)I, (67)Ga, (201)Tl and (57)Co. This tool is widely utilized to evaluate not only the accuracy of radionuclide calibrators, but also the competence of NMSs to measure the activity of the radiopharmaceuticals and the performance of the personnel involved in these measurements. The comparison results showed that 90% of the results received from participants are within the ±10% limit established by the Brazilian Norm.

  20. Discordance of exercise thallium testing with coronary arteriography in patients with atypical presentations

    SciTech Connect

    Bungo, M.W.; Leland, O.S. Jr.

    1983-01-01

    Eighty-one patients with diagnostically difficult clinical presentations suggesting coronary disease underwent symptom-limited maximal-exercise treadmill testing (ETT) and exercise radionuclide scanning with /sup 201/Tl. Results of these tests were in agreement in only 47 percent of the cases. Either exercise thallium or ETT was positive in 94 percent of patients with disease. Among a population with a disease prevalence of 67 percent, agreement between exercise thallium an ETT predicted disease in 92 percent of instances or excluded disease in 82 percent of instances. Frequent discordance between these two tests in 53 percent of the cases unfortunately limits this usefulness.

  1. Investigation of the relationship between linear attenuation coefficients and CT Hounsfield units using radionuclides for SPECT.

    PubMed

    Brown, Saxby; Bailey, Dale L; Willowson, Kathy; Baldock, Clive

    2008-09-01

    This study has investigated the relationship between linear attenuation coefficients (mu) and Hounsfield units (HUs) for six materials covering the range of values found clinically. Narrow-beam mu values were measured by performing radionuclide transmission scans using (99m)Tc, (123)I, (131)I, (201)Tl and (111)In. The mu values were compared to published data. The relationships between mu and HU were determined. These relationships can be used to convert computed tomography (CT) images to mu-maps for single photon emission computed tomography (SPECT) attenuation correction. PMID:18662614

  2. Investigation of optimal acquisition time of myocardial perfusion scintigraphy using cardiac focusing-collimator

    NASA Astrophysics Data System (ADS)

    Niwa, Arisa; Abe, Shinji; Fujita, Naotoshi; Kono, Hidetaka; Odagawa, Tetsuro; Fujita, Yusuke; Tsuchiya, Saki; Kato, Katsuhiko

    2015-03-01

    Recently myocardial perfusion SPECT imaging acquired using the cardiac focusing-collimator (CF) has been developed in the field of nuclear cardiology. Previously we have investigated the basic characteristics of CF using physical phantoms. This study was aimed at determining the acquisition time for CF that enables to acquire the SPECT images equivalent to those acquired by the conventional method in 201TlCl myocardial perfusion SPECT. In this study, Siemens Symbia T6 was used by setting the torso phantom equipped with the cardiac, pulmonary, and hepatic components. 201TlCl solution were filled in the left ventricular (LV) myocardium and liver. Each of CF, the low energy high resolution collimator (LEHR), and the low medium energy general purpose collimator (LMEGP) was set on the SPECT equipment. Data acquisitions were made by regarding the center of the phantom as the center of the heart in CF at various acquisition times. Acquired data were reconstructed, and the polar maps were created from the reconstructed images. Coefficient of variation (CV) was calculated as the mean counts determined on the polar maps with their standard deviations. When CF was used, CV was lower at longer acquisition times. CV calculated from the polar maps acquired using CF at 2.83 min of acquisition time was equivalent to CV calculated from those acquired using LEHR in a 180°acquisition range at 20 min of acquisition time.

  3. Myocardial redistribution of technetium-99m-methoxyisobutyl isonitrile (SESTAMIBI)

    SciTech Connect

    Li, Q.S.; Solot, G.; Frank, T.L.; Wagner, H.N. Jr.; Becker, L.C. )

    1990-06-01

    To determine whether technetium-99m-hexakis-2-methoxyisobutyl isonitrile (SESTAMIBI) remains fixed in the myocardium following its initial uptake or undergoes time-related redistribution, anesthetized dogs underwent occlusion of the anterior descending coronary artery for 6 min, followed by 3-hr reperfusion. Technetium-99m-SESTAMIBI and thallium-201 (201Tl) were injected intravenously after 1 min occlusion and regional myocardial blood flow was measured with radioactive microspheres. Tomographic imaging of Tc-SESTAMIBI revealed a perfusion defect with slight but definite filling in over 2 hr. Quantitative analysis indicated a significant rise in the nadir and decrease in the width of the defect in circumferential profile curves. After 3-hr of reperfusion, Tc-SESTAMIBI activity in the previously ischemic area was always greater than the activity of microspheres injected during coronary occlusion (mean normalized values, 0.32 versus 0.11, p less than 0.0001). Our results indicate that following transient ischemia and reperfusion, Tc-SESTAMIBI clearly undergoes myocardial redistribution, although more slowly and less completely than {sup 201}Tl.

  4. p-Tertbutylcalix[4]arene nanoemulsion: preparation, characterization and comparative evaluation of its decontamination efficacy against Technetium-99m, Iodine-131 and Thallium-201.

    PubMed

    Rana, Sudha; Sharma, Navneet; Ojha, Himanshu; Shivkumar, Hosakote Gurumalappa; Sultana, Sarwat; Sharma, Rakesh Kumar

    2014-05-01

    This study aimed to develop p-tertbutylcalix[4]arene o/w nanoemulsion for decontamination of radioisotopes from skin. Formulation was characterized using dynamic light scattering (DLS), transmission electron microscopy (TEM), multi-photon confocal microscopy techniques and in vitro dissolution studies. In vivo evaluation of nano-emulsion was done using nuclear medicine technique. Stability studies and dermal toxicity studies were also carried out. Comparative decontamination efficacy (DE) studies were performed on synthetic human tissue equivalent material and Sprague Dawley rat against three commonly used medical radioisotopes, i.e., Technetium-99m ((99m)Tc), Iodine-131 ((131)I) and Thallium-201 ((201)Tl). Decontamination was performed using cotton swabs soaked in nanoemulsion at different time intervals of contaminants exposure. Whole body imaging and static counts were recorded using gamma camera before and after each decontamination attempt data was analyzed using one way analysis of variance (ANOVA) and found to be statistically significant (p<0.05). DE of the nanoemulsion loaded with p-tertbutylcalix[4]arene was observed to be 88±5%, 90±3% and 89±3% for (99m)Tc, (131)I and (201)Tl respectively. Dermal toxicity studies revealed no significant differences between treated and control animals. Skin histopathology slides with and without API (Active pharmaceutical ingredients) also found to be comparable. p-Tertbutylcalix[4]arene loaded nanoemulsion shows great promise for skin decontamination against broad ranges of radiological contaminants besides being stable and safe.

  5. Thallium lung-to-heart quantification: three methods of evaluation

    SciTech Connect

    Harler, M.B.; Mahoney, M.; Bartlett, B.; Patel, K.; Turbiner, E.

    1986-12-01

    Lung-to-heart quantification, when used in conjunction with visual assessment of /sup 201/Tl stress test images, has been found useful in diagnosing cardiac dysfunction. The authors evaluated three methods of quantification in terms of inter- and intraobserver variability and reproducibility. Fifty anterior /sup 201/Tl stress images were quantified by each of the following methods: Method A (sum region), which involved one region of interest (ROI) in the measurement of pulmonary activity relative to that of the myocardium; Method B (count density), which required two ROIs, the lung-to-heart ratio being dependent on count density; and Method C (maximum pixel), which used the gray scale of the computer to determine the most intense pixels in the lung field and myocardium. Statistical evaluation has shown that the three methods assess clinical data equally well. Method C was found to be most reproducible in terms of inter- and intraobserver variability followed by Methods A and B. Although nearly equivalent in terms of statistics, the three methods possess inherent differences and therefore should not be used interchangeably without conversion factors.

  6. Half-life measurements of isomeric states populated in projectile fragmentation

    SciTech Connect

    Bowry, M.; Podolay, Zs.

    2012-10-20

    The half-lives of excited isomeric states observed in {sup 195}Au, {sup 201}Tl and {sup 215}Rn are reported for the first time. Delayed {gamma}-rays were correlated with nuclei produced in the projectile fragmentation of relativistic {sup 238}U ions, unambiguously identified in terms of their atomic number (Z) and mass-to-charge ratio (A/Q) after traversing an in-flight separator. The observation of a long-lived isomeric state in {sup 195}Au with t{sub 1/2} = 16{sub -4}{sup +8}{mu}s is presented. Two shorter-lived isomeric states were detected in {sup 201}Tl and {sup 215}Rn with t{sub 1/2} = 95{sub -21}{sup +39} and 57{sub -12}{sup +21} ns respectively. In total 24 isomeric states were identified in different nuclei from Pt to Rn (A {approx} 200) during the current study, the majority of which were previously reported. The wealth of spectroscopic data provides the opportunity to determine the isomeric ratios over a wide range of Z, A and angular momentum (I h) of the reaction products. In particular, high-spin states with I Greater-Than-Or-Equivalent-To 18 h provide a robust test of theoretical models of fragmentation.

  7. Computer-assisted superimposition of magnetic resonance and high-resolution technetium-99m-HMPAO and thallium-201 SPECT images of the brain

    SciTech Connect

    Holman, B.L.; Zimmerman, R.E.; Johnson, K.A.; Carvalho, P.A.; Schwartz, R.B.; Loeffler, J.S.; Alexander, E.; Pelizzari, C.A.; Chen, G.T. )

    1991-08-01

    A method for registering three-dimensional CT, MR, and PET data sets that require no special patient immobilization or other precise positioning measures was adapted to high-resolution SPECT and MRI and was applied in 14 subjects (five normal volunteers, four patients with dementia (Alzheimer's disease), two patients with recurrent glioblastoma, and three patients with focal lesions (stroke, arachnoid cyst and head trauma)). T2-weighted axial magnetic resonance images and transaxial 99mTc-HMPAO and 201Tl images acquired with an annular gamma camera were merged using an objective registration (translation, rotation and rescaling) program. In the normal subjects and patients with dementia and focal lesions, focal areas of high uptake corresponded to gray matter structures. Focal lesions observed on MRI corresponded to perfusion defects on SPECT. In the patients who had undergone surgical resection of glioblastoma followed by interstitial brachytherapy, increased 201Tl corresponding to recurrent tumor could be localized from the superimposed images. The method was evaluated by measuring the residuals in all subjects and translational errors due to superimposition of deep structures in the 12 subjects with normal thalamic anatomy and 99mTc-HMPAO uptake. This method for superimposing magnetic resonance and high-resolution SPECT images of the brain is a useful technique for correlating regional function with brain anatomy.

  8. Thallium 201 uptake in kidneys and heart as an indicator of prognosis in septic shock in the rat

    SciTech Connect

    Senda, M.; Ahmad, M.; Rubin, R.; Strauss, H.W.

    1989-03-01

    The change in distribution of cardiac output in septic shock was examined by radionuclide imaging with thallium 201 thallous chloride (/sup 201/Tl) which allows noninvasive evaluation of relative blood flow to various organs except for the brain. Pseudomonas aeruginosa (1 X 10(9)-2 X 10(10) organisms) were inoculated into the thigh of rats 18-24 hr before the study. The mean arterial pressure was measured with an intracarotid catheter. Fractional blood flow to the heart, kidneys, and liver was evaluated as organ uptake of /sup 201/Tl. Those with zero or less than 5% kidney uptake (n = 8) had a high heart uptake and all died within 3 hr even if their pressure was maintained. In contrast, 20 out of 24 rats with kidney uptake greater than 5% survived for more than 6 hr. Those results suggest that the kidney uptake, representing fractional renal blood flow, is an excellent indicator of short-term prognosis in septic shock.

  9. Monte Carlo evaluation of accuracy and noise properties of two scatter correction methods

    SciTech Connect

    Narita, Y. |; Eberl, S.; Nakamura, T.

    1996-12-31

    Two independent scatter correction techniques, transmission dependent convolution subtraction (TDCS) and triple-energy window (TEW) method, were evaluated in terms of quantitative accuracy and noise properties using Monte Carlo simulation (EGS4). Emission projections (primary, scatter and scatter plus primary) were simulated for {sup 99m}Tc and {sup 201}Tl for numerical chest phantoms. Data were reconstructed with ordered-subset ML-EM algorithm including attenuation correction using the transmission data. In the chest phantom simulation, TDCS provided better S/N than TEW, and better accuracy, i.e., 1.0% vs -7.2% in myocardium, and -3.7% vs -30.1% in the ventricular chamber for {sup 99m}Tc with TDCS and TEW, respectively. For {sup 201}Tl, TDCS provided good visual and quantitative agreement with simulated true primary image without noticeably increasing the noise after scatter correction. Overall TDCS proved to be more accurate and less noisy than TEW, facilitating quantitative assessment of physiological functions with SPECT.

  10. Significance of repeated exercise testing with thallium-201 scanning in asymptomatic diabetic males

    SciTech Connect

    Rubler, S.; Fisher, V.J.

    1985-12-01

    This study was conducted with asymptomatic middle-aged male subjects with diabetes mellitus to detect latent cardiac disease using noninvasive techniques. One group of 38 diabetic males (mean age 50.5 +/- 10.2 years) and a group of 15 normal males (mean age 46.9 +/- 10.0 years) participated in the initial trial; 13 diabetic patients and 7 control subjects were restudied 1-2 years later. Maximal treadmill exercise with a Bruce protocol and myocardial scintigraphy with thallium-201(201Tl) were used. Diabetic subjects on initial examination and retesting achieved a lower maximal heart rate and duration of exercise than control subjects. Abnormal electrocardiographic changes, thallium defects, or both were observed in 23/38 diabetic males (60.5%) on the first study and only one 65-year-old control subject had such findings. On retesting, the control subjects had no abnormalities while 76.9% of diabetic subjects had either 201Tl defects or ECG changes. We conclude that despite the fact that none of diabetic males had any clinical evidence or symptoms of heart disease, this high-risk group demonstrated abnormalities on exercise testing that merit careful subsequent evaluation and followup and could be an effective method of detecting early cardiac disease.

  11. Effects of propranolol and nifedipine on exercise-induced attack in patients variant angina: assessment by exercise thallium-201 myocardial scintigraphy with quantitative rotational tomography

    SciTech Connect

    Kugiyama, K.; Yasue, H.; Horio, Y.; Morikami, Y.; Fujii, H.; Koga, Y.; Kojima, A.; Takahashi, M.

    1986-08-01

    To examine the effects of propranolol and nifedipine on exercise-induced attack in patients with variant angina, exercise /sup 201/Tl myocardial scintigraphy with quantitative analysis by emission-computed tomography was performed in 20 patients with variant angina after oral propranolol (80 mg), nifedipine (20 mg), and placebo. Exercise-induced attack occurred in 11 patients on placebo, in 14 on propranolol, and in none on nifedipine. The exercise duration was significantly shorter in those on propranolol (p less than .05), but significantly longer in patients on nifedipine (p less than .05) than in those on placebo. The peak rate-pressure product was significantly lower in patients on propranolol (p less than .01), but did not change in those on nifedipine, as compared with that in patients on placebo. The size of the perfusion defect as measured by /sup 201/Tl tomography was significantly greater in patients on propranolol (p less than .05), but significantly less in those on nifedipine (p less than .01) than in those on placebo. In conclusion, propranolol does not suppress but rather may aggravate exercise-induced attack in patients with variant angina, while nifedipine suppresses it. This unfavorable effect of propranolol on exercise-induced attack in patients with variant angina is likely to be due to a reduction of regional myocardial blood flow.

  12. Performance of Myocardial Perfusion Imaging Using Multi-focus Fan Beam Collimator with Resolution Recovery Reconstruction in a Comparison with Conventional SPECT

    PubMed Central

    Matsutomo, Norikazu; Nagaki, Akio; Sasaki, Masayuki

    2014-01-01

    Objective(s): IQ-SPECT is an advanced high-speed SPECT modality for myocardial perfusion imaging (MPI), which uses a multi-focus fan beam collimator with resolution recovery reconstruction. The aim of this study was to compare IQ-SPECT with conventional SPECT in terms of performance, based on standard clinical protocols. In addition, we examined the concordance between conventional and IQ_SPECT in patients with coronary artery disease (CAD). Methods: Fifty-three patients, undergoing rest-gated MPI for the evaluation of known or suspected CAD, were enrolled in this study. In each patient, conventional SPECT (99mTc-tetrofosmin, 9.6 min and 201Tl, 12.9 min) was performed, immediately followed by IQ-SPECT, using a short acquisition time (4.3 min for 99mTc-tetrofosmin and 6.2 min for 201Tl). A quantitative analysis was performed on an MPI polar map, using a 20-segment model of the left ventricle. An automated analysis by gated SPECT was carried out to determine the left ventricular volume and function including end-diastolic volume (EDV), end-systolic volume (ESV), and left ventricular ejection fraction (LVEF). The degree of concordance between conventional SPECT and IQ-SPECT images was evaluated according to linear regression and Bland-Altman analyses. Results: The segmental percent uptake exhibited a significant correlation between IQ-SPECT and conventional SPECT (P<0.05). The mean differences in 99mTc-tetrofosmin studies were 1.1±6.6% (apex), 2.8±5.7% (anterior wall), 2.9±6.2% (septal wall), 4.9±6.7% (lateral wall), and 1.8±5.6% (inferior wall). Meanwhile, regarding the 201Tl-SPECT studies, these values were 1.6±6.9%, 2.0±6.6%, 2.1±5.9%, 3.3±7.2%, and 2.4±5.8%, respectively. Although the mean LVEF in IQ-SPECT tended to be higher than that observed in conventional SPECT (conventional SPECT=64.8±11.8% and IQ-SPECT=68.3±12.1% for 99mTc-tetrofosmin; conventional SPECT= 56.0±11.7% and IQ-SPECT=61.5±12.2% for 201Tl), quantitative parameters were not

  13. Dos Hermanas Chicanas: Overcoming Barriers to Professional Advancement

    ERIC Educational Resources Information Center

    Prospero, Moises

    2007-01-01

    Women and ethnic minorities face steep barriers to professional advancement, and those who rise to the executive level typically use a variety of strategies to overcome obstacles in their way. This study first reviewed the literature on barriers to professional advancement for women and ethnic minorities and the strategies that they report using…

  14. Exercise beyond menopause: Dos and Don'ts.

    PubMed

    Mishra, Nalini; Mishra, V N; Devanshi

    2011-07-01

    With a significant number of women belonging to the status of menopause and beyond, it is imperative to plan a comprehensive health program for them, including lifestyle modifications. Exercise is an integral part of the strategy. The benefits are many, most important being maintenance of muscle mass and thereby the bone mass and strength. The exercise program for postmenopausal women should include the endurance exercise (aerobic), strength exercise and balance exercise; it should aim for two hours and 30 minutes of moderate aerobic activity each week. Every woman should be aware of her target heart rate range and should track the intensity of exercise employing the talk test. Other deep breathing, yoga and stretching exercises can help to manage the stress of life and menopause-related symptoms. Exercises for women with osteoporosis should not include high impact aerobics or activities in which a fall is likely. The women and the treating medical practitioner should also be aware of the warning symptoms and contraindications regarding exercise prescription in women beyond menopause. The role of exercise in hot flashes, however, remains inconclusive. Overall, exercising beyond menopause is the only noncontroversial and beneficial aspect of lifestyle modification and must be opted by all. PMID:22408332

  15. Web-Based Mathematics: Some "Dos" and "Don'ts"

    ERIC Educational Resources Information Center

    Loong, Esther Yook-Kin

    2011-01-01

    This case study describes an "out of field" teacher's use of the Internet to teach a range of mathematical topics in a modified Year 8 mathematics class. It highlights the importance of three factors for implementing a discernible web-based teaching strategy: appropriate choice of web objects, effective "virtual" pedagogy, and technical support…

  16. Face mask ventilation--the dos and don'ts.

    PubMed

    Wood, Fiona E; Morley, Colin J

    2013-12-01

    Face mask ventilation provides respiratory support to newly born or sick infants. It is a challenging technique and difficult to ensure that an appropriate tidal volume is delivered because large and variable leaks occur between the mask and face; airway obstruction may also occur. Technique is more important than the mask shape although the size must appropriately fit the face. The essence of the technique is to roll the mask on to the face from the chin while avoiding the eyes, with a finger and thumb apply a strong even downward pressure to the top of the mask, away from the stem and sloped sides or skirt of the mask, place the other fingers under the jaw and apply a similar upward pressure. Preterm infants require continuous end-expiratory pressure to facilitate lung aeration and maintain lung volume. This is best done with a T-piece device, not a self-inflating or flow-inflating bag.

  17. Divorce Matters: Visitation Dos and Don'ts

    MedlinePlus

    ... your former spouse. • Don’t question your children’s loyalty. • Help make the transition from one home to ... Don’t spoil your children to buy their loyalty and love • Don’t let your children blackmail ...

  18. Los Dos Mundos: Rural Mexican Americans, Another America.

    ERIC Educational Resources Information Center

    Baker, Richard

    This book explores race relations between Mexican Americans and Anglo Americans in "Middlewest," a fictitious name for an actual rural Idaho community with the highest proportion of Mexican Americans in the state. Many Mexican Americans in this predominantly agricultural area are current or former migrant workers. The first chapter describes field…

  19. Exercise beyond menopause: Dos and Don’ts

    PubMed Central

    Mishra, Nalini; Mishra, V. N.; Devanshi

    2011-01-01

    With a significant number of women belonging to the status of menopause and beyond, it is imperative to plan a comprehensive health program for them, including lifestyle modifications. Exercise is an integral part of the strategy. The benefits are many, most important being maintenance of muscle mass and thereby the bone mass and strength. The exercise program for postmenopausal women should include the endurance exercise (aerobic), strength exercise and balance exercise; it should aim for two hours and 30 minutes of moderate aerobic activity each week. Every woman should be aware of her target heart rate range and should track the intensity of exercise employing the talk test. Other deep breathing, yoga and stretching exercises can help to manage the stress of life and menopause-related symptoms. Exercises for women with osteoporosis should not include high impact aerobics or activities in which a fall is likely. The women and the treating medical practitioner should also be aware of the warning symptoms and contraindications regarding exercise prescription in women beyond menopause. The role of exercise in hot flashes, however, remains inconclusive. Overall, exercising beyond menopause is the only noncontroversial and beneficial aspect of lifestyle modification and must be opted by all. PMID:22408332

  20. Evolution of the Astronomy Concepts Along Basic Education Cycle. (Breton Title: Evolução dos Conceitos de Astronomia no Decorrer da Educação Básica.) La Evolución de los Conceptos de Astronomía Durante la Educación Básica

    NASA Astrophysics Data System (ADS)

    Darroz, Luiz Marcelo; da Rosa, Cleci Werner; Becker da Rosa, Álvaro; Samudio Pèrez, Carlos Ariel

    2014-07-01

    learning of astronomy in basic education. Embora a astronomia seja considerada uma das ciências mais antigas da humanidade e ainda que a compreensão de seus conceitos tenha trazido enormes avanços para a Ciência e, consequentemente, para a sociedade, observa-se que uma parcela significativa de pessoas encontra-se à margem desses conhecimentos. De acordo com os Parâmetros Curriculares Nacionais para a Educação Básica, cabe à escola a difusão dos conceitos cientificamente corretos, entre eles os relacionados à área de astronomia. Pertinente a essa questão, apresenta-se uma pesquisa realizada com 140 estudantes do nono ano do ensino fundamental e com 120 estudantes da terceira série do ensino médio de quatro escolas da região de Passo Fundo/RS. Buscou-se averiguar, por meio de um questionário composto de questões abertas e de múltipla escolha, o conhecimento desse grupo de estudantes acerca de termos e fenômenos astronômicos básicos e, também, verificar se o índice de acertos cresce à medida que eles avançam nas diferentes e gradativas séries dos ensinos fundamental e médio. De modo geral, os resultados apresentados demonstram que o ensino de astronomia na educação básica enfrenta deficiências. Das 20 questões investigadas, em 17 os índices de acertos são semelhantes nas respostas dadas por estudantes de nível fundamental e médio, revelando que muitas concepções equivocadas permanecem ao longo da educação básica. Isso evidencia que tais temas não são - ou são pouco - abordados durante esses dois níveis de escolarização. Assim, conclui-se que a discussão dos conceitos relacionados com a astronomia deve receber maior ênfase na abordagem dos diferentes conteúdos, sendo necessária uma ação nacional em prol do seu ensino. Acredita-se que essa ação nacional deve estar apoiada em um pilar triplo de atores coletivos: comunidade científica, comunidade astronômica semiprofissional e comunidade escolar. Por fim, esse pilar seria

  1. Difficulties of First Years Elementary School Teachers with the Teaching of Astronomy. (Breton Title: Dificuldades de Professores dos Anos Iniciais do Ensino Fundamental em Relação ao Ensino da Astronomia. ) Dificultades de LOS Profesores de los Primeros Años de la Escuela Primaria en Relación a la Enseñanza de la Astronomía

    NASA Astrophysics Data System (ADS)

    Langhi, Rodolfo; Nardi, Roberto

    2005-12-01

    This paper reports Primary School teachers' discourses analysis about their difficulties related to the teaching of Astronomy. It reports partial data of a master's level research carried out in the last two years, named "An exploratory study for inserting Astronomy in primary school teachers' education" (LANGHI, 2004). The study took into consideration students' and teachers' common sense conceptions about astronomical phenomena, conceptual mistakes in textbooks, and Astronomy's suggestions given by the PCN (Parâmetros Curriculares Nacionais - The Brazilian National Curriculum Standards). The paper aims to characterize teachers' difficulties, in order to provide subsides to the implementation of an initial or continuing education program. This study is justified by the fact that courses plans like these only will be adapted to the teacher's (and students') reality, if there is a primary investigation about what the teachers really need to know about Astronomy. This fact was possible here by the enunciations interpretation of a teachers' sample using semi-structured interviews, according to discourse analysis procedures. The research outcomes show difficulties related to factors like: those of personal order, methodological, on teacher's formation, educational infrastructure and other related to information sources for educators. Este artigo, que relata as dificuldades de professores em relação ao ensino da Astronomia, faz parte de um estudo exploratório para a inserção da Astronomia na formação de professores dos anos iniciais do Ensino Fundamental. Esse estudo leva em consideração as concepções alternativas de alunos e professores sobre fenômenos astronômicos, os erros conceituais em livros didáticos e as sugestões de conteúdos de Astronomia constantes nos PCN (Parâmetros Curriculares Nacionais). Caracterizar as dificuldades dos professores é a questão central deste texto, apontando para o objetivo de contribuir com subsídios para um futuro

  2. Difficulties of First Years Elementary School Teachers with the Teaching of Astronomy. (Breton Title: Dificuldades de Professores dos Anos Iniciais do Ensino Fundamental em Relação ao Ensino da Astronomia. ) Dificultades de LOS Profesores de los Primeros Años de la Escuela Primaria en Relación a la Enseñanza de la Astronomía

    NASA Astrophysics Data System (ADS)

    Langhi, Rodolfo; Nardi, Roberto

    2005-12-01

    This paper reports Primary School teachers' discourses analysis about their difficulties related to the teaching of Astronomy. It reports partial data of a master's level research carried out in the last two years, named "An exploratory study for inserting Astronomy in primary school teachers' education" (LANGHI, 2004). The study took into consideration students' and teachers' common sense conceptions about astronomical phenomena, conceptual mistakes in textbooks, and Astronomy's suggestions given by the PCN (Parâmetros Curriculares Nacionais - The Brazilian National Curriculum Standards). The paper aims to characterize teachers' difficulties, in order to provide subsides to the implementation of an initial or continuing education program. This study is justified by the fact that courses plans like these only will be adapted to the teacher's (and students') reality, if there is a primary investigation about what the teachers really need to know about Astronomy. This fact was possible here by the enunciations interpretation of a teachers' sample using semi-structured interviews, according to discourse analysis procedures. The research outcomes show difficulties related to factors like: those of personal order, methodological, on teacher's formation, educational infrastructure and other related to information sources for educators. Este artigo, que relata as dificuldades de professores em relação ao ensino da Astronomia, faz parte de um estudo exploratório para a inserção da Astronomia na formação de professores dos anos iniciais do Ensino Fundamental. Esse estudo leva em consideração as concepções alternativas de alunos e professores sobre fenômenos astronômicos, os erros conceituais em livros didáticos e as sugestões de conteúdos de Astronomia constantes nos PCN (Parâmetros Curriculares Nacionais). Caracterizar as dificuldades dos professores é a questão central deste texto, apontando para o objetivo de contribuir com subsídios para um futuro

  3. Semi-automated measurements of heart-to-mediastinum ratio on 123I-MIBG myocardial scintigrams by using image fusion method with chest X-ray images

    NASA Astrophysics Data System (ADS)

    Kawai, Ryosuke; Hara, Takeshi; Katafuchi, Tetsuro; Ishihara, Tadahiko; Zhou, Xiangrong; Muramatsu, Chisako; Abe, Yoshiteru; Fujita, Hiroshi

    2015-03-01

    MIBG (iodine-123-meta-iodobenzylguanidine) is a radioactive medicine that is used to help diagnose not only myocardial diseases but also Parkinson's diseases (PD) and dementia with Lewy Bodies (DLB). The difficulty of the segmentation around the myocardium often reduces the consistency of measurement results. One of the most common measurement methods is the ratio of the uptake values of the heart to mediastinum (H/M). This ratio will be a stable independent of the operators when the uptake value in the myocardium region is clearly higher than that in background, however, it will be unreliable indices when the myocardium region is unclear because of the low uptake values. This study aims to develop a new measurement method by using the image fusion of three modalities of MIBG scintigrams, 201-Tl scintigrams, and chest radiograms, to increase the reliability of the H/M measurement results. Our automated method consists of the following steps: (1) construct left ventricular (LV) map from 201-Tl myocardium image database, (2) determine heart region in chest radiograms, (3) determine mediastinum region in chest radiograms, (4) perform image fusion of chest radiograms and MIBG scintigrams, and 5) perform H/M measurements on MIBG scintigrams by using the locations of heart and mediastinum determined on the chest radiograms. We collected 165 cases with 201-Tl scintigrams and chest radiograms to construct the LV map. Another 65 cases with MIBG scintigrams and chest radiograms were also collected for the measurements. Four radiological technologists (RTs) manually measured the H/M in the MIBG images. We compared the four RTs' results with our computer outputs by using Pearson's correlation, the Bland-Altman method, and the equivalency test method. As a result, the correlations of the H/M between four the RTs and the computer were 0.85 to 0.88. We confirmed systematic errors between the four RTs and the computer as well as among the four RTs. The variation range of the H

  4. Heterogeneity of SPECT bull`s-eyes in normal dogs: Comparison of attenuation compensation algorithms

    SciTech Connect

    DiBella, E.V.R.; Eisner, R.L.; Schmarkey, L.S.; Barclay, A.B.; Patterson, R.E.; Nowak, D.J.; Lalush, D.S.; Tsui, B.M.W. ||

    1995-08-01

    In normal dogs, SPECT {sup 99m}Tc Sestamibi (MIBI) and {sup 201}Tl myocardial perfusion images reconstructed with filtered backprojection (FBP) show a large decrease of counts in the septal wall (S) compared to the lateral wall (L). The authors evaluated the iterative method of Chang at 0 and 1 iterations (Chang0 and Chang1), and the Maximum Likelihood-Expectation Maximization with attenuation compensation (ML-EM-ATN) algorithm on data acquired from 5 normal dogs and from simulated projection data using a homogeneous count-density model of a normal canine myocardium in the attenuation field measured in one dog. Mean counts in the S and L regions were calculated from maximum-count circumferential profile arrays. Their results demonstrate that ML-EM-ATN and Chang1 result in improved uniformity, as measured by the S/L ratio.

  5. High-precision γ -ray spectroscopy of the cardiac PET imaging isotope 82Rb and its impact on dosimetry

    NASA Astrophysics Data System (ADS)

    Nino, M. N.; McCutchan, E. A.; Smith, S. V.; Lister, C. J.; Greene, J. P.; Carpenter, M. P.; Muench, L.; Sonzogni, A. A.; Zhu, S.

    2016-02-01

    82Rb is a positron-emitting isotope used in cardiac positron emission tomography (PET) imaging which has been reported to deliver a significantly lower effective radiation dose than analogous imaging isotopes like 201Tl and 99 mTc sestamibi. High-quality β -decay data are essential to accurately appraise the total dose received by the patients. A source of 82Sr was produced at the Brookhaven Linac Isotope Producer (BLIP), transported to Argonne National Laboratory, and studied with the Gammasphere facility. Significant revisions have been made to the level scheme of 82Kr including 12 new levels, 50 new γ -ray transitions, and the determination of many new spin assignments through angular correlations. These new high-quality data allow a precise reappraisal of the β -decay strength function and thus the consequent dose received by patients.

  6. Nuclear medicine imaging in tuberculosis using commercially available radiopharmaceuticals.

    PubMed

    Sathekge, Mike; Maes, Alex; D'Asseler, Yves; Vorster, Mariza; Van de Wiele, Christophe

    2012-06-01

    In this paper, data available on nuclear medicine imaging using commercially available radiopharmaceuticals for the differentiation, staging, and prediction or assessment of the response to treatment in tuberculosis (TB) are reviewed. Limited available studies suggest that single photon emission computed tomography (SPECT) using either 201Tl, 99mTc-sestamibi, or 99mTc-tetrofosmin is accurate (≥85%) and has a high negative predictive value (≥90%) for the differentiation of TB from carcinoma in patients presenting with a solitary pulmonary nodule (SPN). The criteria for detection of TB on 201Tl SPECT are nondepiction of the suspicious lesion in the delayed image or a negative retention index [washout on the delayed images (3–4 h postinjection) vs. the early image (5–15 min postinjection)] and a comparable-to-background uptake on 99mTc-sestamibi or 99mTc-tetrofosmin SPECT. Another SPECT tracer of potential interest for the differentiation of TB from malignant SPN that warrants further exploration, is N-isopropyl-p-[123I]iodoamphetamine (123I-IMP). In contrast, 18F-fluorodeoxyglucose (18F-FDG) PET is unable to differentiate malignancy from TB and thus cannot be used as a tool to reduce futile biopsy/thoracotomy in these patients. A limited number of studies have reported on the potential of nuclear medicine imaging in assessment of the extent of disease in patients with extrapulmonary TB using 67Ga-citrate SPECT and 18F-FDG PET, respectively. 67Ga-citrate SPECT was shown to be as sensitive as bone scintigraphy for the detection of bone infection and was found to be complementary to computed tomography (CT) imaging. 18F-FDG PET was found to be significantly more efficient when compared with CT, respectively, in over half of patients for the identification of sites of lymph node involvement that were missed by CT and often the only sites of extrapulmonary TB identified. Unfortunately, 18F-FDG PET findings did not lead to alterations in treatment planning in any

  7. Proficiency tests in the determination of activity of radionuclides in radiopharmaceutical products measured by nuclear medicine services in 8 years of comparison programmes in Brazil.

    PubMed

    Tauhata, Luiz; Iwahara, Akira; de Oliveira, Antonio E; Rezende, Eduarda Alexandre; Delgado, José Ubiratan; da Silva, Carlos José; Dos Santos, Joyra A; Nícoli, Ieda G; Alabarse, Frederico G; Xavier, Ana Maria

    2008-01-01

    Proficiency tests were applied to assess the performance of 74 nuclear medicine services in activity measurements of (131)I, (123)I, (99)Tc(m), (67)Ga and (201)Tl. These tests produced 913 data sets from comparison programmes promoted by the National Laboratory for Ionizing Radiation Metrology (LNMRI) from 1999 to 2006. The data were evaluated against acceptance criteria for accuracy and precision and assigned as Acceptable or Not acceptable accordingly. In addition, three other statistical parameters were used as complementary information for performance evaluation which related to normative requirements and to radionuclide calibrators. The results have shown a necessity to improve quality control procedures and unsatisfactory performances of radionuclide calibrators, which incorporate Geiger-Müller detectors.

  8. Atrophic nerve fibers in regions of reduced MIBG uptake in doxorubicin cardiomyopathy

    SciTech Connect

    Takano, Hajime; Ozawa Hideyuki; Kobayashi, Isao

    1995-11-01

    A myocardial MIBG-SPECT examination was conducted 2 wk after doxorubicin chemotherapy on a 52-yr-old woman without cardiac symptoms. Despite normal {sup 201}Tl scintigraphy, reduced MIBG uptake was detected in the apical anterior, inferior and lateral segments of the left ventricle. The patient died of congestive heart failure due to doxorubicin-induced cardiomyopathy 10 mo later. At necropsy, the left ventricle was markedly dilated and the apical anterior, inferior and lateral walls were thin, stiff and whitish. Nerve fibers in the apical inferior wall were atrophic and markedly fibrotic where MIBG uptake was most reduced. Nerve fibers in the septum were normal where MIBG uptake had remained normal. The histologic findings correspond with the findings on the MIBG image. MIBG imaging may detect cardiac sympathetic denervation in doxorubicin-induced cardiomyopathy before cardiac symptoms are manifest and cardiac function deteriorates. 5 refs., 2 figs.

  9. Age-specific inhalation radiation dose commitment factors for selected radionuclides

    SciTech Connect

    Strenge, D.L.; Peloquin, R.A.; Baker, D.A.

    1982-08-01

    Inhalation dose commitment factors are presented for selected radionuclides for exposure of individuals in four age groups: infant, child, teen and adult. Radionuclides considered are /sup 35/S, /sup 36/Cl, /sup 45/Ca, /sup 67/Ga, /sup 75/Se, /sup 85/Sr, /sup 109/Cd, /sup 113/Sn, /sup 125/I, /sup 133/Ba, /sup 170/Tm, /sup 169/Yb, /sup 182/Ta, /sup 192/Ir, /sup 198/Au, /sup 201/Tl, /sup 204/Tl, and /sup 236/Pu. The calculational method is based on the human metabolic model of ICRP as defined in Publication 2 (ICRP 1959) and as used in previous age-specific dose factor calculations by Hoenes and Soldat (1977). Dose commitment factors are presented for the following organs of reference: total body, bone, liver, kidney, thyroid, lung and lower large intestine.

  10. [Evaluation of non-uniform attenuation correction using simultaneous transmission and emission computed tomography--basic analysis with myocardial phantom].

    PubMed

    Otake, H; Yukihiro, M; Fukushima, Y; Imai, T; Hosono, K; Hatori, N; Watanabe, N; Hirano, T; Inoue, T; Takahashi, M; Ban, R; Endo, K

    1996-03-01

    Simultaneous transmission emission protocol (STEP), developed for the non-uniform attenuation correction of single photon emission computed tomography (SPECT) was evaluated using the cardiac phantom prepared with and without a myocardial wall defect. Emission computed tomography (ECT) of the cardiac phantom using 201Tl was acquired. Transmission data (TCT) were taken using a line source of 99mTc. Myocardial images with STEP method were superior in the homogeneity of intramyocardial radioactivity and spatial resolution to the conventional SPECT images. This is an excellent method because of the accurate matching position between TCT and ECT images and shortening the examination time by simultaneous data acquisition. It would be clinically useful for diagnosing various myocardial diseases.

  11. Heavy-ion versus {sup 3}He/{sup 4}He fusion-fission reactions: Angular momentum dependence of dissipation in nuclear fission

    SciTech Connect

    Ye, W.

    2011-09-15

    The stochastic Langevin model is employed to study dissipation properties in fission in the {sup 16}O + {sup 181}Ta {yields}{sup 197}Tl system by analyzing prescission neutron yields measured in this reaction. It has been found that the {sup 197}Tl nuclei undergo fission that is not in accordance with the standard Bohr-Wheeler statistical theory. A detailed comparison with previously published work in which fission excitation functions measured in {sup 3,4}He + {sup 197}Au {yields}{sup 200,201}Tl are shown to be in excellent agreement with the fission width formula predicted by the traditional models of nuclear fission suggests that nuclear dissipation strength may have an angular momentum dependence in addition to the known deformation and temperature dependence. Implications for the basic understanding of the observed abnormal rise in prescission particles at high energy and the need for further experimental confirmations are discussed.

  12. How reliable is myocardial imaging in the diagnosis of acute myocardial infarction

    SciTech Connect

    Willerson, J.T.

    1983-01-01

    Myocardial scintigraphic techniques available presently allow a sensitive and relatively specific diagnosis of acute myocardial infarction when they are used correctly, although every technique has definite limitations. Small myocardial infarcts (less than 3 gm.) may be missed, and there are temporal limitations in the usefulness of the scintigraphic techniques. The development of tomographic methodology that may be used with single-photon radionuclide emitters (including technetium and /sup 201/Tl will allow the detection of relatively small abnormalities in myocardial perfusion and regions of myocardial infarction and will help to provide a more objective interpretation of the myocardial scintigrams. The use of overlay techniques allowing simultaneous assessment of myocardial perfusion, infarct-avid imaging, and radionuclide ventriculograms will provide insight into the relevant aspects of the extent of myocardial damage, the relationship of damage to myocardial perfusion, and the functional impact of myocardial infarction on ventricular performance.

  13. Risk stratification after myocardial infarction. Clinical overview

    SciTech Connect

    O'Rourke, R.A. )

    1991-09-01

    Many patients with an acute myocardial infarction can be stratified into subgroups that are at high risk for morbidity and mortality on the basis of clinical characteristics that indicate recurrent myocardial ischemia, persistent left ventricular dysfunction, and/or recurrent cardiac arrhythmias. In patients with uncomplicated myocardial infarction the assessment of symptoms, physical findings, and ECG changes during predischarge exercise testing often identifies patients at increased risk for further cardiac events. Because of the suboptimum sensitivity and specificity of the exercise ECG for detecting myocardial ischemia, myocardial perfusion imaging with 201Tl and/or assessment of global and segmental ventricular function by two-dimensional echocardiography or radionuclide cineangiography during or immediately after exercise are often added to the predischarge risk stratification.

  14. Nuclear medicine imaging in tuberculosis using commercially available radiopharmaceuticals.

    PubMed

    Sathekge, Mike; Maes, Alex; D'Asseler, Yves; Vorster, Mariza; Van de Wiele, Christophe

    2012-06-01

    In this paper, data available on nuclear medicine imaging using commercially available radiopharmaceuticals for the differentiation, staging, and prediction or assessment of the response to treatment in tuberculosis (TB) are reviewed. Limited available studies suggest that single photon emission computed tomography (SPECT) using either 201Tl, 99mTc-sestamibi, or 99mTc-tetrofosmin is accurate (≥85%) and has a high negative predictive value (≥90%) for the differentiation of TB from carcinoma in patients presenting with a solitary pulmonary nodule (SPN). The criteria for detection of TB on 201Tl SPECT are nondepiction of the suspicious lesion in the delayed image or a negative retention index [washout on the delayed images (3–4 h postinjection) vs. the early image (5–15 min postinjection)] and a comparable-to-background uptake on 99mTc-sestamibi or 99mTc-tetrofosmin SPECT. Another SPECT tracer of potential interest for the differentiation of TB from malignant SPN that warrants further exploration, is N-isopropyl-p-[123I]iodoamphetamine (123I-IMP). In contrast, 18F-fluorodeoxyglucose (18F-FDG) PET is unable to differentiate malignancy from TB and thus cannot be used as a tool to reduce futile biopsy/thoracotomy in these patients. A limited number of studies have reported on the potential of nuclear medicine imaging in assessment of the extent of disease in patients with extrapulmonary TB using 67Ga-citrate SPECT and 18F-FDG PET, respectively. 67Ga-citrate SPECT was shown to be as sensitive as bone scintigraphy for the detection of bone infection and was found to be complementary to computed tomography (CT) imaging. 18F-FDG PET was found to be significantly more efficient when compared with CT, respectively, in over half of patients for the identification of sites of lymph node involvement that were missed by CT and often the only sites of extrapulmonary TB identified. Unfortunately, 18F-FDG PET findings did not lead to alterations in treatment planning in any

  15. Possibility of determination of the asymptotic level-density parameter

    SciTech Connect

    Kudyaev, G.A.; Ostapenko, Y.B.; Svirin, M.I.; Smirenkin, G.N.

    1988-02-01

    We investigate the sensitivity of the fissility of nuclei to the parameters of the density of excited levels and conclude that the nuclei in the region of Pb are most favorable for an experimental estimate of the asymptotic parameter a-italic-tilde = ..cap alpha..A. The mean value ..cap alpha.. = 0.086 +- 0.009 MeV/sup -1/ is found from analysis of the fission of seven nuclei from /sup 201/Tl to /sup 213/At. This value is in agreement with the phenomenological description of the energy dependence a(U) (..cap alpha.. = 0.093 MeV/sup -1/) and with the theoretical prediction ..cap alpha.. = 0.09 MeV/sup -1/ obtained for a Woods-Saxon potential.

  16. Gold-195m first-pass radionuclide ventriculography, thallium-201 single-photon emission CT, and 12-lead ECG stress testing as a combined procedure

    SciTech Connect

    Kipper, S.L.; Ashburn, W.L.; Norris, S.L.; Rimkus, D.S.; Dillon, W.A.

    1985-09-01

    Graded, sequential, rest/exercise, gold-195m, first-pass ventriculography and thallium-201 (Tl-201) single-photon emission computed tomography (SPECT) were performed simultaneously during a single, electrocardiograph-monitored, bicycle stress test in 24 individuals. The technical aspects and logistics involved in performing this combined radionuclide study are stressed in this preliminary report. Fourteen healthy volunteers each had a normal left ventricular ejection fraction and wall-motion response, along with normal T1-201 perfusion and washout, as determined by both visual and quantitative analysis of the tomographic sections. Each of ten patients with coronary artery disease had at least one abnormality of these parameters. The authors suggest that it is technically feasible to evaluate both cardiac function and myocardial perfusion simultaneously by combing Au-195m ventriculography and Tl-201 SPECT imaging into a single, noninvasive, diagnostic package.

  17. Exercise supplementation of dipyridamole for myocardial perfusion imaging

    SciTech Connect

    DePuey, E.G.

    1991-08-01

    The substitution of intravenous dipyridamole for symptom-limited treadmill exercise has provided a non-invasive means to diagnose coronary artery disease with 201Tl scintigraphy in patients unable to adequately exercise. Limitations of dipyridamole/thallium imaging are primarily due to suboptimal image quality secondary to hepatic tracer concentration and decreased test sensitivity in patients who are dipyridamole non-responders. Low-level treadmill exercise supplementation improves image quality, whereas handgrip has little, if any, benefit. The effect of low-level exercise in augmenting coronary blood flow is unknown and reports regarding the effect of handgrip are conflicting. The diagnostic benefit of these maneuvers in improving test sensitivity and decreasing the number of non-responders has not been documented. The combination of maximal, symptom-limited treadmill exercise and intravenous dipyridamole is a theoretically attractive option to improve overall test sensitivity, but the physiologic consequences and potential side effects should be more thoroughly investigated.

  18. Proficiency tests in the determination of activity of radionuclides in radiopharmaceutical products measured by nuclear medicine services in 8 years of comparison programmes in Brazil.

    PubMed

    Tauhata, Luiz; Iwahara, Akira; de Oliveira, Antonio E; Rezende, Eduarda Alexandre; Delgado, José Ubiratan; da Silva, Carlos José; Dos Santos, Joyra A; Nícoli, Ieda G; Alabarse, Frederico G; Xavier, Ana Maria

    2008-01-01

    Proficiency tests were applied to assess the performance of 74 nuclear medicine services in activity measurements of (131)I, (123)I, (99)Tc(m), (67)Ga and (201)Tl. These tests produced 913 data sets from comparison programmes promoted by the National Laboratory for Ionizing Radiation Metrology (LNMRI) from 1999 to 2006. The data were evaluated against acceptance criteria for accuracy and precision and assigned as Acceptable or Not acceptable accordingly. In addition, three other statistical parameters were used as complementary information for performance evaluation which related to normative requirements and to radionuclide calibrators. The results have shown a necessity to improve quality control procedures and unsatisfactory performances of radionuclide calibrators, which incorporate Geiger-Müller detectors. PMID:18346902

  19. A new quantitative method for the analysis of cardiac perfusion tomography (SPET): validation in post-infarct patients treated with thrombolytic therapy.

    PubMed

    Mortelmans, L; Nuyts, J; Scheys, I; Wackers, F; Lesaffre, E; Brzostek, T; De Roo, M; De Geest, H; Suetens, P; Verbruggen, A

    1993-12-01

    In this study a new method for assessment of perfusion defects (PDs) derived from myocardial perfusion tomograms was evaluated in patients treated with thrombolytic therapy. Using global constraints and dynamic programming, a model-based delineation algorithm defined myocardial borders, the basal plane and absolute and relative PD size in 49 thallium-201 chloride (201TL CL) and 60 technetium-99m methoxyisobutylisonitrile (99mTc-MIBI) tomograms. Tomographic (single-photon emission tomography: SPET) and planar quantification of PDs was compared to enzymatic infarct size as well as to global (LVEF) and regional ventricular function (RWM) obtained by contrast angiography. The algorithm delineated the myocardium and the valve plane in most cases, even when large PDs were present. Manual correction of the automatic delineation of the basal plane was necessary in less than 20% of the studies. Using 201Tl Cl, LVEF correlated better with tomographic PD (r = -0.67) than with planar PD (r = -0.54). Comparing planar to tomographic imaging using 99mTc-MIBI, a higher correlation with enzymatic infarct size (r = 0.73 vs 0.57) and with global ventricular function (r = 0.64 vs -0.52) was found when tomographic techniques were used. No close correlation between PD and RWM was found. The beneficial effect of thrombolysis was shown by a significant difference of PD in patients with open versus occluded infarct-related vessels. It can be concluded that this new automated algorithm for quantification of SPET perfusion defect size provides a useful tool in evaluating thrombolytic therapy.

  20. Verapamil prevents silent myocardial perfusion abnormalities during exercise in asymptomatic patients with hypertrophic cardiomyopathy

    SciTech Connect

    Udelson, J.E.; Bonow, R.O.; O'Gara, P.T.; Maron, B.J.; Van Lingen, A.; Bacharach, S.L.; Epstein, S.E.

    1989-05-01

    Recent studies indicate that reversible 201Tl perfusion defects, compatible with silent myocardial ischemia, commonly develop during exercise in asymptomatic or mildly symptomatic patients with hypertrophic cardiomyopathy (HCM). To determine whether this represents a dynamic process that may be modified favorably by medical therapy, we studied 29 asymptomatic or minimally symptomatic patients with HCM, aged 12-55 years (mean, 28), with exercise 201Tl emission computed tomography under control conditions and again after 1 week of oral verapamil (mean dosage, 453 mg/day). Treadmill time increased slightly during verapamil (21.0 +/- 3.6 to 21.9 +/- 2.7 minutes, p less than 0.005), but peak heart rate-blood pressure product was unchanged (26.3 +/- 6.0 X 10(3)) compared with 25.0 +/- 6.4 X 10(3). Two midventricular short-axis images per study were divided into five regions each, and each of these 10 regions was then analyzed on a 0-2 scale by three observers blinded with regard to the patients' therapy. Average regional scores of 1.5 or less were considered to represent perfusion defects, and a change in regional score of 0.5 or more was considered to constitute a significant change. During control studies, 15 patients (52%) developed perfusion defects with exercise (average, 3.7 regions per patient). In 14 of these patients, all perfusion defects completely reversed after 3 hours of rest; one patient had fixed defects. After administration of verapamil, exercise perfusion scores improved in 10 of the 14 patients (71%) with reversible defects; there was overall improvement in 34 of 50 (68%) regions with initially reversible perfusion defects.

  1. Establishing the Empirical Relationship Between Non-Science Majoring Undergraduate Learners' Spatial Thinking Skills and Their Conceptual Astronomy Knowledge. (Spanish Title: Estableciendo Una Relación Empírica Entre el Razonamiento Espacial de los Estudiantes de Graduación de Carreras no Científicas y su Conocimento Conceptual de la Astronomía.) Estabelecendo Uma Relação Empírica Entre o RacioCínio Espacial dos Estudantes de Graduação EM Carreiras Não Científicas e Seu Conhecimento Conceitual da Astronomia

    NASA Astrophysics Data System (ADS)

    Heyer, Inge; Slater, Stephanie J.; Slater, Timothy F.

    2013-12-01

    The astronomy education community has tacitly assumed that learning astronomy is a conceptual domain resting upon spatial thinking skills. As a first step to formally identify an empirical relationship, undergraduate students in a non-major introductory astronomy survey class at a mediumsized, Ph.D. granting, mid-western US university were given pre- and post-astronomy conceptual diagnostics and spatial reasoning diagnostics, Instruments used were the "Test Of Astronomy Standards" and "What Do You Know?" Using only fully matched data for analysis, our sample consisted of 86 undergraduate non-science majors. Students' normalized gains for astronomy surveys were low at .26 and .13 respectively. Students' spatial thinking was measured using an instrument designed specifically for this study. Correlations between the astronomy instruments' pre- to post-course gain scores and the spatial assessment instrument show moderate to strong relationships suggesting the relationship between spatial reasoning and astronomy ability can explain about 25% of the variation in student achievement. La comunidad de educación en astronomía ha supuesto de forma tácita que el aprendizaje de la astronomía consiste en un dominio conceptual fundamentado en el razonamiento espacial. Como un primer paso para identificar formalmente una relación empírica entre estas dos cosas, utilizamos como muestra los estudantes de graduación de carreras no científicas de un curso experimental en una universidad norteamericana del medioeste de porte mediano con programa de Doctorado em curso, en el cual estos estudiantes se sometieron a un diagnóstico de razonamiento espacial y conceptos astronómicos antes e después del mismo. Las herramientas utilizadas fueron el Test Of Astronomy Standards (TOAST) y el cuestionario What do you know? Utilizando solo los datos completamente consistentes para este análisis, nuestra muestra consistió en 86 estudantes de graduación. Las mejoras, depués de

  2. Apparent Motion of the Sun, Shadows of Objects and Measurement of Time in the View of Seventh Grade Students of Middle School. (Breton Title: Movimento Aparente do Sol, Sombras dos Objetos e Medição do Tempo na Visão de Alunos do Sétimo Ano do Ensino Fundamental.) Movimiento Aparente del Sol, Sombras de los Objetos y Medición del Tiempo en la Visión de Estudiantes del Séptimo Grado del Ciclo Pirmario

    NASA Astrophysics Data System (ADS)

    Iria Machado, Daniel

    2013-07-01

    The apparent motion of the Sun on the celestial sphere and the behavior of the shadows of objects over time are observable phenomena in everyday life. However, students often do not have a proper understanding of such occurrences, and can even display misconceptions about them. Therefore, we performed a research in order to know students' notions about these subjects and to evaluate the contribution to their understanding brought about by an activity performed with an interactive sundial in an informal learning environment. We investigated the ideas of 43 students from the seventh grade of middle school by applying a test with open questions before and after an activity with an analemmatic sundial, conducted by a monitor. A significant proportion of students were initially unaware of most of the phenomena treated. The intervention performed helped the students to assimilate new concepts, providing the contact with new phenomena and to a lesser degree, the development of explanations about them, indicating an educational potential of this action. However, the contribution to the understanding of some of the ideas explored was small, pointing to the need to make additional observations, studies and discussions. O movimento aparente do Sol na esfera celeste e o comportamento das sombras dos objetos com o passar do tempo são fenômenos observáveis no dia a dia. No entanto, muitas vezes os estudantes não possuem uma compreensão adequada de tais ocorrências, podendo inclusive exibir concepções alternativas a seu respeito. Por isso, efetuou-se uma pesquisa com o intuito de conhecer as noções dos alunos sobre esses temas e avaliar a contribuição para seu entendimento propiciada por uma atividade feita com um relógio de Sol interativo, em um ambiente de ensino informal. Foram investigadas as ideias de 43 alunos do sétimo ano do Ensino Fundamental mediante a aplicação de um teste com questões abertas antes e depois de uma atividade com um relógio de Sol

  3. Sobre las soluciones acotadas del problema instantáneo de dos cuerpos

    NASA Astrophysics Data System (ADS)

    Altavista, C.

    La demostración se basa en el hecho de que las integrales del problema de los N-cuerpos admiten componentes en el campo complejo según las raíces n-ésimas de la unidad. Definida la matriz unitaria correspondiente, la fórmula de Cayley permite transformar la matriz unitaria en una matriz hermitiana. Utilizando como parámetros los cosenos direccionales de un sistema de coordenadas orbitales referidos a un sistema de referencia fijo, puede construirse, utilizando el operador hermitiano antes definido, una forma cuadrática cuyas raíces mínima y máxima definen las cotas respectivas de los movimientos de los mencionados cosenos direccionales.

  4. 33 CFR 101.505 - Declaration of Security (DoS).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., or between vessels in the case of a vessel-to-vessel activity, as to the respective security measures each must undertake during a specific vessel-to-facility interface, during a series of interfaces between the vessel and the facility, or during a vessel-to-vessel activity. (b) Details as to who...

  5. 33 CFR 101.505 - Declaration of Security (DoS).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., or between vessels in the case of a vessel-to-vessel activity, as to the respective security measures each must undertake during a specific vessel-to-facility interface, during a series of interfaces between the vessel and the facility, or during a vessel-to-vessel activity. (b) Details as to who...

  6. 33 CFR 105.245 - Declaration of Security (DoS).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... vessels subject to part 104, of this subchapter must sign and implement DoSs as required in (b)(1) and (2... with this section. (g) A copy of all currently valid continuing DoSs must be kept with the...

  7. Conditions of Collaboration: A Dean's List of Dos and Don'ts.

    ERIC Educational Resources Information Center

    Glotzbach, Philip A.

    2001-01-01

    Presents relational and structural conditions necessary to successful collaboration between college faculty and administrators. Relational conditions include "refuse to play zero-sum games" and "the most important power in a college is the power to persuade." Structural conditions include "clarify the roles of players" and "prefer a matrix…

  8. órbitas espectroscópicas de dos sistemas binarios tempranos usando correlaciones cruzadas bidimensionales

    NASA Astrophysics Data System (ADS)

    González, J. F.; Lapasset, E.

    We apply the two-dimensional cross-correlation technique TODCOR to derive spectroscopic orbits for the two B-type double-lined spectroscopic binaries HD 66066A and HD 315031, previously mentioned as blue straggler candidates of the open clusters NGC 2516 and NGC 6530, respectively. Reliable radial velocities for both components are measured even for orbital phases for which the separation between the spectral lines are about 0.5 times the quadratic sum of the full-width at half-maximum of the lines. Both binaries have circular orbits and the orbital periods are 1.67 and 1.38 days for HD 66066A and HD 315031, respectively. We calculate minimum masses with errors of 3-5% and obtain the projected radii from the line widths. We derive absolute stellar parameters which are consistent with the age and distance of the clusters. Both binary systems are formed by main-sequence stars and it is expected that they will experience mass-transfer between their components before the end of the core H-burning stage. HD 315031 is likely a triple system as suggested by the variation of the center-of-mass velocity.

  9. Dos Idiomas, Un Mundo. Dual Language Project. Title VII Biennial Evaluation Report, 1995-97.

    ERIC Educational Resources Information Center

    Ernest, Harishini M.; Gonzalez, Rosa M.

    This is an evaluation of the first 2 years of a 5-year comprehensive Bilingual Education grant funded by Title VII Part A of the Improving America's Schools Act of 1994 in the Austin Independent School District (AISD) (Texas). The grant awarded to the AISD funds a program of Developmental Bilingual Education at two elementary schools where more…

  10. Land disposal of San Luis drain sediments, Panoche Water District, South Dos Palos, California

    SciTech Connect

    Zawislanski, Peter; Benson, Sally; TerBerg, Robert; Borglin, Sharon

    2002-07-01

    Lawrence Berkeley National Laboratory (LBNL), LFR Levine-Fricke (LFR), the U.S. Bureau of Reclamation (USBR) and the Panoche Water District, have completed a pilot-scale test of the viability of land application of selenium- (Se-) enriched San Luis Drain (SLD) sediments. The project was initiated in October 1998 by LBNL. LFR assumed the role of primary subcontractor on the project in July 2001. Substantial portions of this report, describing work performed prior to November 2000, were previously prepared by LBNL personnel. The data set, findings, and recommendations are herein updated with information collected since November 2000. Local land disposal is an attractive option due to its low cost and the proximity of large areas of available land. Two modes of disposal are being tested: (1) the application to a nearby SLD embankment, and (2) the application to and incorporation with nearby farm soils. The study of these options considers the key problems that may potentially arise from this approach. These include disturbance of SLD sediments during dredging, resulting in increased downstream Se concentrations; movement of the land-applied Se to groundwater; reduced productivity of farm crops; and Se uptake by wild and crop plants. This report describes field and laboratory activities carried out from 1998 through February 2002, and results of these investigations.

  11. 33 CFR 104.255 - Declaration of Security (DoS).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... engaging in a vessel-to-vessel activity, prior to the activity, the respective Masters, VSOs, or their... any passenger embarkation or disembarkation or cargo transfer operation, the respective Masters, VSOs... disembarkation or cargo transfer operation, the respective Masters, VSOs, or designated representatives must...

  12. 33 CFR 104.255 - Declaration of Security (DoS).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... engaging in a vessel-to-vessel activity, prior to the activity, the respective Masters, VSOs, or their... any passenger embarkation or disembarkation or cargo transfer operation, the respective Masters, VSOs... disembarkation or cargo transfer operation, the respective Masters, VSOs, or designated representatives must...

  13. 33 CFR 104.255 - Declaration of Security (DoS).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... engaging in a vessel-to-vessel activity, prior to the activity, the respective Masters, VSOs, or their... any passenger embarkation or disembarkation or cargo transfer operation, the respective Masters, VSOs... disembarkation or cargo transfer operation, the respective Masters, VSOs, or designated representatives must...

  14. 33 CFR 104.255 - Declaration of Security (DoS).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... engaging in a vessel-to-vessel activity, prior to the activity, the respective Masters, VSOs, or their... any passenger embarkation or disembarkation or cargo transfer operation, the respective Masters, VSOs... disembarkation or cargo transfer operation, the respective Masters, VSOs, or designated representatives must...

  15. 33 CFR 104.255 - Declaration of Security (DoS).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... engaging in a vessel-to-vessel activity, prior to the activity, the respective Masters, VSOs, or their... any passenger embarkation or disembarkation or cargo transfer operation, the respective Masters, VSOs... disembarkation or cargo transfer operation, the respective Masters, VSOs, or designated representatives must...

  16. Home before You Know It = De regres en casa en un dos por tres.

    ERIC Educational Resources Information Center

    Vida Health Communications, Inc., Cambridge, MA.

    The arrival of a newborn requires a great deal of adjustment. Intended for new and expectant parents, this booklet and companion video provide practical advice and hands-on demonstrations of the essentials of mother and baby care, from birth to the first visit to the pediatrician. The first part of the booklet, which comes in both English- and…

  17. Entre Dos Mundos/Between Two Worlds: Bicultural Development in Context

    ERIC Educational Resources Information Center

    Bacallao, Martica L.; Smokowski, Paul R.

    2009-01-01

    How do Mexican immigrant adolescents balance different, and often oppositional, cultural influences in the acculturation process? In this article, we explore how acculturating adolescents absorb cultural messages and go about creating their (multiple) identities. Guided by Alternation Theory, in-depth qualitative interviews were conducted with 12…

  18. The Politics of Hispanic Education. Un Paso pa'lante y dos pa'tras.

    ERIC Educational Resources Information Center

    Meier, Kenneth J.; Stewart, Joseph, Jr.

    This book presents an in-depth examination of 142 U.S. school districts (containing at least 5,000 students and 5 percent Hispanic enrollment) in order to understand Hispanic inequities in education and what can be done to correct these inequities. Chapter 1 presents political theory of educational policy. Chapter 2 presents an overview of the…

  19. Unidad: Las influencias culturales en el arte mexicana (Unit: Cultural Influences in Mexican Art). Dos semanas.

    ERIC Educational Resources Information Center

    Finere, Neal

    This two-week unit, appropriate for bilingual education settings as well as foreign language programs, deals with the three primary cultural influences found in Mexican contemporary art. The multisensory materials, pragmatic focus, and direct creative student involvement are designed to make it a microcosmic, real-life experience. The first part…

  20. Influencias africanas na lingua brasileira dos terreiros (African Influences in Brazilian Language of the Voodoo Rites).

    ERIC Educational Resources Information Center

    Megenney, William W.

    1991-01-01

    Discusses how determination of lexical items with Sub-Saharan origin in songs of voodoo rites of candomble and umbanda in southern and northeastern Brazil is complicated by factors like existence of phonological correspondence without accompanying semantic correspondence, difficulty of determining meaning of word in a given text, and high…

  1. Abundancias químicas de dos binarias de HgMn

    NASA Astrophysics Data System (ADS)

    Gonzalez, E. J.; González, J. F.; Collado, A. E.

    We present the results of the abundance analysis of two HgMn single-line binary systems: NGC 2287-106 and NGC 6025-14. The spectroscopic ob- servations have been carried out at the Complejo Astronómico el Leon-cito (CASLEO) with the REOSC spectrograph in cross-dispersion mode, cov- ering the spectral range 3800-5800 ≈. Compared to the Sun, NGC 6025-14 shows great overabundances of Hg, Mn, P, Ga and Xe, while Hg, Mn, Sr, Pt and Zr are overabundant in NGC 2287-106. FULL TEXT IN SPANISH

  2. The "Dos and Don'ts" of Writing a Journal Article

    ERIC Educational Resources Information Center

    Kekale, Tauno; de Weerd-Nederhof, Petra; Cervai, Sara; Borelli, Massimo

    2009-01-01

    Purpose: During work as reviewers and editors of journals authors are often faced the same types of problems in many articles. The purpose of this piece is to give some guidelines on typical problems that lead to rejection, and how to avoid these. Design/methodology/approach: The paper discusses journal article design and offers some methodology…

  3. Aspectos linguisticos dos emprestimos em portugues (Linguistic Aspects of Adaptation into Portuguese).

    ERIC Educational Resources Information Center

    Harmon, Ronald M.

    1994-01-01

    Examines the process through which modern Portuguese borrows from other languages, mainly French and English. Portuguese adapts these derivatives to conform to its own rules of phonology, morphology, and semantics. (four references) (Author/CK)

  4. A social media primer for professionals: digital dos and don'ts.

    PubMed

    Bernhardt, Jay M; Alber, Julia; Gold, Robert S

    2014-03-01

    Social media sites have become powerful and important tools for health education, promotion, and communication activities as they have dramatically grown in popularity. Social media sites also offer many features that can be used for professional development and advancement. When used wisely and prudently, social media sites and platforms offer great potential for professional development by building and cultivating professional networks, as well as sharing information to increase one's recognition and improve one's reputation. They also provide a medium for increasing one's knowledge and awareness of timely news and trends by following important organizations, opinion leaders, and influential professionals. When used unwisely and imprudently, there is the potential to delay, damage, or even destroy one's professional and personal life. In this commentary, we offer recommendations for using Facebook, LinkedIn, and Twitter for professional development and caution against online behaviors that may have negative professional consequences. In summary, we believe that the strengths and benefits of social media for professional advancement and development far outweigh the risks and encourage health promotion professionals to properly engage these powerful tools.

  5. Dos Puertorriquenos Visitan Puerto Rico (Two Puerto Ricans Visit Puerto Rico).

    ERIC Educational Resources Information Center

    Tuttle, Harry Grover

    These materials for Spanish instruction are based on the meeting and friendship of two Puerto Ricans arriving in Puerto Rico for visits to their hometowns, their discussions of Puerto Rican life, and a sightseeing tour of San Juan. Introductory passages to the visitors' dialogues are in English, and dialogues are in Spanish, with photographs,…

  6. A social media primer for professionals: digital dos and don'ts.

    PubMed

    Bernhardt, Jay M; Alber, Julia; Gold, Robert S

    2014-03-01

    Social media sites have become powerful and important tools for health education, promotion, and communication activities as they have dramatically grown in popularity. Social media sites also offer many features that can be used for professional development and advancement. When used wisely and prudently, social media sites and platforms offer great potential for professional development by building and cultivating professional networks, as well as sharing information to increase one's recognition and improve one's reputation. They also provide a medium for increasing one's knowledge and awareness of timely news and trends by following important organizations, opinion leaders, and influential professionals. When used unwisely and imprudently, there is the potential to delay, damage, or even destroy one's professional and personal life. In this commentary, we offer recommendations for using Facebook, LinkedIn, and Twitter for professional development and caution against online behaviors that may have negative professional consequences. In summary, we believe that the strengths and benefits of social media for professional advancement and development far outweigh the risks and encourage health promotion professionals to properly engage these powerful tools. PMID:24396119

  7. Buscando Su Voz en Dos Culturas = Finding Your Voice in Two Cultures.

    ERIC Educational Resources Information Center

    Cline, Zulmara

    1998-01-01

    An administrator/former teacher ponders difficulties of living in two cultures: a professional world that respects her degrees and credentials and a Latina world that questions pursuit of the "American dream." Although she used her American voice to coax a Latina student back to school, she sympathized with the mother's family-centered aspirations…

  8. The Puerto Ricans--Two Communities, One Culture. (Los Puertorriquenos--Dos Comunidades, Una Cultura.)

    ERIC Educational Resources Information Center

    Vivo, Paquita

    1980-01-01

    Puerto Rican roots stem from the ethnic mixture of Indians, Europeans, and Africans. This article describes the advent of each of the groups on the island, the historical and cultural impact each made, and the retention of heritage among Puerto Rican migrants to the U.S. (DS)

  9. Use of elephant grass for energy production in Campos dos Goytacazes-RJ, Brazil.

    PubMed

    Daher, R F; Souza, L B; Gravina, G A; Machado, J C; Ramos, H C C; Silva, V Q R; Menezes, B R S; Schneider, L S A; Oliveira, M L F; Gottardo, R D

    2014-01-01

    Elephant grass is a tropical forage plant widely distributed throughout Brazil. It was first exclusively used in the livestock sector as cattle feed. The grass is characterized by its high productivity and photosynthetic capacity and is considered as an alternative source of renewable energy. Here, we estimated the general combining ability of the parents and specific combining ability of the hybrids based on morpho-agronomic biomass-quality traits. The experiment was conducted in a randomized block design with 3 replicates. The diallel was composed of 16 hybrids and 2 groups of genitors. In the diallel analysis of variance, we observed a significant difference among treatments. A significant difference was observed among genitors for dry matter production (DMP). For the general combining ability of group 1, the traits leaf blade width, DMP, height, percentage of neutral detergent fiber, percentage of hemicellulose, percentage of lignin, percentage of acid detergent fiber, and percentage of cellulose were significant. For the estimates of general combining ability of DMP, parents Porto Rico 534-B, Vruckwona, Taiwan A-146, and Mercker S. E. A. were 0.4748, 3.2819, 1.1659, and 0.4317. The parents of Mercker S. E. A. and Porto Rico 534-B produced the highest percentage of detergent fiber and percentage of lignin with values of 0.1482 and 0.0856. Thus, parents Vruckwona, Porto Rico 534-B, and Taiwan A-146 are promising for integration into breeding programs. The best hybrid combinations for DMP were 1 x 5, 1 x 8, 2 x 6, 3 x 7, and 4 x 5. PMID:25526210

  10. Dos and Don'ts of Giving OTC Cough and Cold Medicines to Your Child

    MedlinePlus

    ... packages to keep track of important labels and expiration dates. Do store all medicines up and away, out ... prevent them from becoming less effective before their expiration dates. Don’ts Don’t give OTC cough and ...

  11. VizieR Online Data Catalog: The Solar Twin Planet Search. IV. (dos Santos+, 2016)

    NASA Astrophysics Data System (ADS)

    Dos Santos, L. A.; Melendez, J.; Do Nascimento, J.-D. Jr; Bedell, M.; Ramirez, I.; Bean, J. L.; Asplund, M.; Spina, L.; Dreizler, S.; Alves-Brito, A.; Casagrande, L.

    2016-07-01

    Ages, the measured projected rotational velocities (vsini) and stellar parameters of the 81 solar twins and the Sun. The ages of all solar twins and stellar parameters for HIP68468 were obtained by Tucci Maia et al. (2016A&A...590A..32T). Stellar parameters for the other solar twins were obtained by Ramirez et al. (2014A&A...572A..48R). The vsini were measured by line profile fitting using red spectra from HARPS (R=115000). Macroturbulence velocities were inferred from the scaling Eq. 2 in our study. (1 data file).

  12. [Relations between location of elements in periodic table and affinity for the kidneys (author's transl)].

    PubMed

    Ando, A; Hisada, K; Ando, I

    1977-10-01

    The distribution of many inorganic compounds in rats was investigated in order to evaluate kidney affinity of inorganic compounds. In these experiments, 30%, 10-20% and 4-10% of administered dose was localized in the kidneys in 203Hg-acetate and 203 Bi-acetate, in H198AuCl4, 103PdCl2, 201TlCl, 210Pd(NO3)2 and H2(127M)TeO3, and in Na2(51)CrO4, 54MnCl2, (114m)InCl3 and 7BeCl2, respectively. Some bipositive ions and anions was hardly taken up into the kidneys. And in many hard acids according to classification of Lewis acids, the uptake rate into the kidneys was usually small. On the other hand, Hg, Au and Bi, which have strong binding power to the protein, showed high uptake rate in the kidneys. As Hg++, Au+ and Bi+++ was soft acids according to classification of Lewis acids, it was thought that these elements would bind strongly to soft base (RSH, RS-) present in the kidney.

  13. Thallium-201 is comparable to technetium-99m-sestamibi for estimating cardiac function in patients with abnormal myocardial perfusion imaging.

    PubMed

    Wu, Ming-Che; Tsai, Cheng-Ting; Lin, Hui-Chun; Sun, Fang-Ju; Lin, Ku-Hung

    2015-11-01

    We analyzed the left-ventricular functional data obtained by cardiac-gated single-photon emission computed tomography myocardial perfusion imaging (MPI) with thallium-201 (Tl-201) and technetium-99m-sestamibi (MIBI) protocols in different groups of patients, and compared the data between Tl-201 and MIBI. Two hundred and seventy-two patients undergoing dipyridamole stress/redistribution Tl-201 MPI and 563 patients undergoing 1-day rest/dipyridamole stress MIBI MPI were included. Higher mean stress ejection fraction (EF), rest EF, and change in EF (ΔEF) were noticed in the normal MPI groups by both Tl-201 and MIBI protocols. Higher mean EF was observed in the females with normal MPI results despite their higher mean age. Comparisons between the Tl-201 and MIBI groups suggested a significant difference in all functional parameters, except for the rest end diastolic volume/end systolic volume and ΔEF between groups with negative MPI results. For the positive MPI groups, there was no significant difference in all parameters, except for the change in end diastolic volume and change in end systolic volume after stress between both protocols. The Tl-201 provides comparable left-ventricular functional data to MIBI cardiac-gated single-photon emission computed tomography in patients with positive MPI results, and may therefore be undertaken routinely for incremental functional information that is especially valuable to this patient group.

  14. Complete improvement in a patient with multiple irreversible defects of the left ventricle on 99m technetium-sestamibi SPECT after percutaneous coronary intervention.

    PubMed

    Javadi, H; Porpiranfar, M A; Semnani, S; Jallalat, S; Yavari, P; Mogharrabi, M; Hooman, A; Amini, A; Barekat, M; Iranpour, D; Assadi, M; Asli, I N

    2012-10-01

    99mTc-sestamibi has been investigated as a potential viability marker; initial studies have shown good concordance between 201Tl and 99mTc-sestamibi activities in both viable and nonviable myocardium. However, assessment of myocardial viability by 99mTc-sestamibi remains controversial for tissue recovery after revascularization. Here, we present a patient with several regions of severely diminished and irreversible (defect persisting in both early and delay images of each set scanning) defects on initial scan which were dissolved completely on the follow up scan after an intervention. In a 75 year-old Asian woman with acute myocardial infarction who received thrombolytic therapy and subjected to percutaneous coronary angiography (PCI) on day 28 after acute myocardial infarction(MI), resting 99mTc-sestamibi SPECT was applied on day 4 (initial scan) and 138 (follow up scan) after acute MI at 30 and 180 min after injection of tracer (740 MBq); Two-dimensional echocardiography was carried out at the same time. On the initial image set, there was irreversible defects in the apex, anteroapical, inferoapical, anteroseptal, septal and also anterior walls, while the follow up image was normal in all regions.The angiography intervention showed just significant stenosis on left anterior descending (LAD) vessel (95%). This may highlight the failure of 99mTc-sestamibi as a marker of myocardial viability and also mandate further validating of the procedure with follow up scan or other modalities for myocardial viability investigation.

  15. Tl-201 and Tc-99m-Sestamibi SPECT for brain tumor detection: Comparison using MRI coregistration

    SciTech Connect

    Darcourt, J.; Itti, L.; Chang, L.

    1994-05-01

    Tl-201 (Tl) brain SPECT has been validated for the differential diagnosis of high versus low grade gliomas and recurrence versus radiation necrosis. We compared this technique to Tc-99m-Sestamibi (MIBI) SPECT in 9 patients (pts) with brain tumors using MRI coregistration. Pts were injected with 4 mCi of Tl and brain SPECT was performed using a dedicated brain system. This was immediately following by an injection of 20 mCi of MIBI and a brain SPECT using the same camera and with the pt in the same position. Four pts were studied for the diagnosis of radiation necrosis vs. tumor recurrence (2 had biopsy proven recurrence); 5 pts were studied for primary tumor evaluation: 2 meningiomas, 1 oligodendroglioma, 1 low-grade astrocytoma, 1 cysticercosis. Coregistration was performed for every pt by 3D surface fitting of the inner skull MIBI contour to the MRI brain surface extracted automatically. ROIs were drawn on the MRI and applied to the coregistered MIBI and Tl images for tumor to non-tumor ratios T/NT calculations. There was a tight correlation between MIBI and Tl T/NT (r-0.96) and a 1.5 threshold separated radiation necrosis from recurrence and low from high grade primary tumors. Therefore, the data already available on Tl brain tumor imaging can be used with MIBI SPECT with the advantage of a better image quality (2.5 to 4 times more counts).

  16. Experimental studies of the physiologic properties of technetium-99m agents: Myocardial transport of perfusion imaging agents

    SciTech Connect

    Meerdink, D.J.; Leppo, J.A. )

    1990-10-16

    The physiologic properties of new technetium-99m-labeled myocardial imaging agents (Tc-99m sestamibi, an isonitrile; and Tc-99m teboroxime, a boronic acid adduct of technetium dioxime) are discussed and compared to thallium-201 (Tl-201). Studies with isolated hearts, subcellular fractions and cell cultures indicate that Tc-99m sestamibi, Tc-99m teboroxime and Tl-201 do not share common transport or sequestration mechanisms. Although peak Tc-99m sestamibi myocardial extraction over time is about half that of Tl-201 at equivalent coronary blood flows, the amount of Tc-99m sestamibi that remains in the heart is similar to that of Tl-201 because of its higher retention efficiency. The high retention efficiency for Tc-99m sestamibi also results in minimal redistribution. In contrast, Tc-99m teboroxime myocardial extraction is higher than that of Tl-201, but its retention is less efficient, resulting in relatively rapid washout characteristics which may quickly result in tracer redistribution. During reperfusion after a no-flow period, Tc-99m sestamibi extraction and retention increase, but for Tc-99m teboroxime and Tl-201 these values tend to decrease. All tracers show adequate transport characteristics for perfusion imaging, and differences in transport and retention should lead to the development of new clinical protocols.27 references.

  17. Nuclear Imaging of Amyloidosis

    PubMed Central

    Cytawa, Wojciech; Teodorczyk, Jacek; Lass, Piotr

    2014-01-01

    Summary Amyloidosis is a clinical condition caused by deposition of various protein fibrills in extracellular space. The presented symptoms depend on the type of deposits and the organ or organs involved. The correct diagnosis is often difficult, due to lack of nonivasive imaging techniques and insufficiency of morphological imaging procedures delievered by radiology. We presented a list of potential radiopharmaceuticals that can be used in detecting various types of amyloidoses. 123I-SAP proved to have high sensitivity in imaging of AA and AL amyloidosis in visceral organs. 99mTc-Aprotinin was found to be useful in detecting cardiac amyloidosis. A couple of classical radiotracers, such as 201Tl, 123I-mIBG, together with 111In-antimyosin were also tested for accuracy in cardiac imaging, however the main problem was low specificity. Potential applicability was also found in case of some bone-seeking agents and other radiotracers, e.g. 67Ga-citrate and 99mTc-penta-DMSA. High sensitivity and specificity was achieved with β2-microglobulin labeled with 131I or 111In. Among PET tracers, 11C-PIB deserves more attention, because it may have an important role in diagnosing of AD in the near future. Further clinical studies are expected to take place, because noninvasive diagnosing and monitoring of amyloidosis is still a challenge. PMID:25071873

  18. Comparison of thallium-201 and technetium-99m hexakis 2-methoxyisobutyl isonitrile single-photon emission computed tomography for estimating the extent of myocardial ischemia and infarction in coronary artery disease.

    PubMed

    Narahara, K A; Villanueva-Meyer, J; Thompson, C J; Brizendine, M; Mena, I

    1990-12-15

    Single-photon emission computed tomography (SPECT) using thallium-201 (Tl-201) was compared with technetium-99m hexakis 2-methoxyisobutyl isonitrile (Tc-99m MIBI) in 24 patients with coronary artery diseaes. Patients exercised to the same work load as each isotope was studied. Normal and hypoperfused left ventricular mass was determined with an automated method. Estimated total left ventricular mass was similar for both stress/redistribution Tl-201 and stress/rest Tc-99m MIBI images. The mean estimated defect size in the redistribution Tl-201 images was 32 +/- 34.7 vs 33 +/- 38.4 g in the resting Tc-99m MIBI studies (difference not significant). The individual determinations of defect mass were highly correlated (r = 0.93; p less than 0.0001). Estimated defect size in the stress Tl-201 images (52 +/- 46.2 g) was significantly larger than the exercise Tc-99m MIBI estimates of defect mass (42 +/- 39.9 g; p less than 0.05). A linear correlation existed between stress thallium and technetium estimates of defect size (r = 0.85) but 15 of 24 Tc-99m MIBI defects were smaller than the Tl-201 defects. Partial redistribution of Tc-99m MIBI could explain the discordance. Stress Tc-99m MIBI SPECT defect size determined by visual interpretation or by the use of isocount analysis may be smaller than what is seen with stress Tl-201 SPECT.

  19. Parathyroid scans and thyroid uptake of thallium 201 of subjects in chronic hemodialysis

    SciTech Connect

    Maayan, M.L.; Rubin, J.E.; Berlyne, G.; Volpert, E.M.; Sellitto, R.; Schor, S.; Braunstein, D.; Johnson, R.; Wallace, E.Z.; Bitton, R.N.

    1984-01-01

    Patients in chronic hemodialysis were injected i.v. 1mCi each Thallium Chloride 201 (TlCl) and Technetium 99m pertechnetate (Tc99m) and imagings of the thyroid and parathyroid glands were taken after 30, 60 and 90'. Parathyroid scans were obtained by computerized subtraction of the Tc99m from the TlCl image. The percentage uptake of TlCl and Tc99m was measured at 1 and 3 hrs in normal, hemodialyzed and thyroxine treated subjects as well as in untreated and thyroxine treated mice. Thyroid tests and serum electrolytes were routinely determined. Enlarged parathyroid glands were visualized in 5 out of 6 patients on hemodialysis. TlCl uptake was greatly decreased and thyroid imagings poor in patients in renal failure. This was parallel in all cases with a high serum K/sup +/. Tc99m uptake and scans were unaffected by renal status. Administration of L-thyroxine greatly reduced the thyroidal uptake and accompanying scans after both Tc99m and TlCl in human subjects as well as in experimental animals. The authors conclude the following: a) TlCl - Tc99m subtraction scans enabled visualization of hyperplastic parathyroid glands in patients in chronic hemodialysis; b) Thyroid uptake of TlCl was inversely related to the serum K/sup +/ level; and c) Both Tc99m and TlCl thyroidal uptake were inhibited by administration of L-thyroxine, hence TSH dependent.

  20. Dose coefficients for intakes of radionuclides via contaminated wounds.

    PubMed

    Toohey, R E; Bertelli, L; Sugarman, S L; Wiley, A L; Christensen, D M

    2011-05-01

    The NCRP Wound Model, which describes the retention of selected radionuclides at the site of a contaminated wound and their uptake into the transfer compartment, has been combined with the ICRP element-specific systemic models for those radionuclides to derive dose coefficients for intakes via contaminated wounds. These coefficients can be used to generate derived regulatory guidance (i.e., the activity in a wound that would result in an effective dose of 20 or 50 mSv, or in some cases, a organ-equivalent dose of 500 mSv) and clinical decision guidance (i.e., activity levels that would indicate the need for consideration of medical intervention to remove activity from the wound site, administration of decorporation therapy or both). Data are provided for 38 radionuclides commonly encountered in various activities such as nuclear weapons, fuel fabrication or recycling, waste disposal, medicine, research, and nuclear power. These include 3H, 14C, 32P, 35S, 59Fe, 57,58,60Co, 85,89,90Sr, 99mTc, 106Ru, 125,129,131I, 134,137Cs, 192Ir, 201Tl, 210Po, 226,228Ra, 228,230,232Th, 234,235,238U, 237Np, 238,239,240,241Pu, 241Am, 242,244Cm, and 252Cf.

  1. The role of thallium-201 and pentavalent dimercaptosuccinic acid for staging cartilaginous tumours

    PubMed Central

    Choong, Peter FM; Kunisada, Toshiyuki; Slavin, John; Schlicht, Stephen; Hicks, Rodney

    2004-01-01

    Introduction Heterogeneity of cartilage tumours may confound accurate diagnosis and grading resulting in under and over treatment. Improved preoperative assessment of malignancy and grade would be invaluable for developing a rational plan for treatment. We examined correlations between nuclear tracer avidity and malignancy grade in cartilage tumours. Methods Between 1996 and 2000, 92 consecutive patients with cartilaginous tumours (50 benign, 42 non-metastatic malignant) underwent nuclear scanning. Thallium-201 (TL-201) and pentavalent dimercaptosuccinic acid (DMSAV) were used as nuclear isotopes. Scanning with these agents was performed on separate days 48 hours apart. Static and SPECT images were obtained at 30 m and 4 h after injection of nuclear tracer. Pathology review was undertaken blinded to the results of the nuclear scans and correlations between histologic results and trace uptake at 4 hours examined. Results 25 patients with negative DMSAV had benign tumours. 15/17 tumours with positive TL-201 had malignant tumours. 11/13 patients with both positive DMSAV and TL-201 scans had intermediate or high grade tumours and 4 of these developed metastases. We have developed an algorithm for the management of patients with tumours that aims to avoid over treatment of low grade tumours and under treatment of high grade tumours. Conclusion Functional nuclear scanning with TL-201 and DMSAV complements other imaging modalities in the management of cartilaginous tumours. PMID:15533251

  2. 99mTc-human immunoglobulin (HIG) in AIDS patients: first results.

    PubMed

    Galli, G; Salvatori, M; Antoni, M; Ortona, L; Ventura, G; Maiuro, G; Pirronti, T; Marano, P

    1991-01-01

    Scintigraphy with 99mTc labelled human polyclonal immunoglobulin was performed in 16 patients with ascertained or suspected AIDS-related infections. 99mTc-HIG lung scanning was compared, in 11 patients, with 67Ga scintigraphy, chest X-ray and high resolution lung CT. 67Ga and 99mTc-HIG were concordantly positive in five cases of BAL-ascertained Pneumocystis carinii pneumonia (PCP), while one of them was Rx and CT negative. X-ray, 67Ga and 99mTc were concordantly negative in 5 cases. 99mTc-HIG yielded negative results in two cases of Mycobacterium infection, both of which were 67Ga and Rx positive: Mycobacterium avium in diffuse lung involvement and Mycobacterium TBC in excavated infiltrate. 99mTc-HIG was also positive in other 3 AIDS patients: 1 case of intestinal cryptosporidiosis, 1 pulmonary abscess (Staphylococcus and Candida), and 1 sacral abscess; it was negative in 1 case of Kaposi sarcoma (also 201Tl negative). In conclusion, 99mTc-HIG scintigraphy in AIDS patients is feasible, and offers some practical advantages (continuous availability, fast response time, etc.). The initial results seem similar to those of 67Ga in lung scanning (and perhaps more specific for PCP).

  3. Dose rate measurements from radiopharmaceuticals: implications for nuclear medicine staff and for children with radioactive parents.

    PubMed

    Greaves, C D; Tindale, W B

    1999-02-01

    Following the introduction of a number of radiopharmaceuticals, we assessed the dose received by staff working in the nuclear medicine department and also by children who may be in close contact with a radioactive parent. We measured departure dose rates (microSv.h-1) at distances of 0.1, 0.5 and 1.0 m from the skin surface at the level of the thyroid, chest and bladder of patients undergoing the following nuclear medicine procedures: MUGA scans using 99Tcm-labelled red blood cells, myocardial perfusion scans using 99Tcm-labelled radiopharmaceuticals, lymphoscintigraphy using colloidal 99Tcm (Re) sulphide, bone scans using 99Tcm-labelled oxidronate, 111In-octreotide scans, 111In-labelled leukocyte studies and cardiac reinjection studies using 201Tl. The maximum dose rates at 0.1 m were those from MUGA studies (167.3 microSv.h-1) and myocardial perfusion studies (one-day protocol = 391.7 microSv.h-1, two-day protocol = 121.8 microSv.h-1). The implications of these dose rates on both technical and nursing staff are assessed. Also, the dose received by an infant in close contact with a parent following a nuclear medicine investigation was estimated.

  4. Comparison of thallium-201 and technetium-99m hexakis 2-methoxyisobutyl isonitrile single-photon emission computed tomography for estimating the extent of myocardial ischemia and infarction in coronary artery disease

    SciTech Connect

    Narahara, K.A.; Villanueva-Meyer, J.; Thompson, C.J.; Brizendine, M.; Mena, I. )

    1990-12-15

    Single-photon emission computed tomography (SPECT) using thallium-201 (Tl-201) was compared with technetium-99m hexakis 2-methoxyisobutyl isonitrile (Tc-99m MIBI) in 24 patients with coronary artery diseaes. Patients exercised to the same work load as each isotope was studied. Normal and hypoperfused left ventricular mass was determined with an automated method. Estimated total left ventricular mass was similar for both stress/redistribution Tl-201 and stress/rest Tc-99m MIBI images. The mean estimated defect size in the redistribution Tl-201 images was 32 +/- 34.7 vs 33 +/- 38.4 g in the resting Tc-99m MIBI studies (difference not significant). The individual determinations of defect mass were highly correlated (r = 0.93; p less than 0.0001). Estimated defect size in the stress Tl-201 images (52 +/- 46.2 g) was significantly larger than the exercise Tc-99m MIBI estimates of defect mass (42 +/- 39.9 g; p less than 0.05). A linear correlation existed between stress thallium and technetium estimates of defect size (r = 0.85) but 15 of 24 Tc-99m MIBI defects were smaller than the Tl-201 defects. Partial redistribution of Tc-99m MIBI could explain the discordance. Stress Tc-99m MIBI SPECT defect size determined by visual interpretation or by the use of isocount analysis may be smaller than what is seen with stress Tl-201 SPECT.

  5. Prognostic impact of stress testing in coronary artery disease

    SciTech Connect

    Severi, S.; Michelassi, C. )

    1991-05-01

    Observational data prospectively collected permit the examination of a complex set of decisions, including the decision not to perform any stress testing. Patients with or without previous myocardial infarction admitted for coronary evaluation and not submitted to any stress testing because of clinical reasons are at a higher risk for subsequent death. For prognostication, no test has been better validated than exercise electrocardiography: it can identify patients at low and high risk for future cardiac events among those without symptoms, with typical chest pain, and with previous myocardial infarction. In patients with triple-vessel disease, the results of exercise also allow those at low and high risk to be recognized. Both exercise radionuclide angiography and {sup 201}Tl scintigraphy (the latter in larger patient populations) have also demonstrated significant prognostic value on patients with or without previous myocardial infarction. Neither one has shown superiority to the other in prognostication. So far, they have been considered the only viable alternatives to exercise electrocardiography stress testing for diagnosis and prognostication. However, their costs limit their extensive application. Preliminary data suggest that intravenous dipyridamole echocardiography can be used for both diagnosis and prognostication of coronary artery disease; moreover, the prognostic information derived from dipyridamole echocardiography testing seems independent of and additive to that provided by exercise electrocardiography. Further prospective studies on larger patient populations are needed to better define the prognostic value of dipyridamole echocardiography testing.47 references.

  6. Prediction of death, myocardial infarction, and worsening chest pain using thallium scintigraphy and exercise electrocardiography

    SciTech Connect

    Staniloff, H.M.; Forrester, J.S.; Berman, D.S.; Swan, H.J.

    1986-12-01

    Although used extensively, there is little published information on the prognostic ability of exercise /sup 201/Tl scintigraphy. Accordingly, 1 yr after testing we contacted 819 patients without previous MI or CABG seen in our laboratory during a 2-yr period. Events were defined as death from a cardiovascular cause, nonfatal MI, or worsening clinical state requiring CABG. The event rate was 3.9 events per 100 patients per year. There was univariate prognostic information when comparing the highest and lowest categories as risk ratios for chest pain characteristics (2.7), sex (2.3), exercise duration (3.1), ST slope (2.5), and thallium pattern (11.6), intensity of perfusion defect (17.2), and number of abnormal regions (8.7). However, the strongest predictors were also the least common. Prognostic ability was improved by combining the results categorically, as the number of abnormal tests (13.9). The highest risk ratio, 20.5:1, was obtained by combining results through discriminant function analysis. We conclude that exercise thallium scintigraphy provides prognostic information, although the most predictive patterns are uncommon. Combining the results of multiple test results improves the prognostic ability.

  7. Thallium-201 is comparable to technetium-99m-sestamibi for estimating cardiac function in patients with abnormal myocardial perfusion imaging.

    PubMed

    Wu, Ming-Che; Tsai, Cheng-Ting; Lin, Hui-Chun; Sun, Fang-Ju; Lin, Ku-Hung

    2015-11-01

    We analyzed the left-ventricular functional data obtained by cardiac-gated single-photon emission computed tomography myocardial perfusion imaging (MPI) with thallium-201 (Tl-201) and technetium-99m-sestamibi (MIBI) protocols in different groups of patients, and compared the data between Tl-201 and MIBI. Two hundred and seventy-two patients undergoing dipyridamole stress/redistribution Tl-201 MPI and 563 patients undergoing 1-day rest/dipyridamole stress MIBI MPI were included. Higher mean stress ejection fraction (EF), rest EF, and change in EF (ΔEF) were noticed in the normal MPI groups by both Tl-201 and MIBI protocols. Higher mean EF was observed in the females with normal MPI results despite their higher mean age. Comparisons between the Tl-201 and MIBI groups suggested a significant difference in all functional parameters, except for the rest end diastolic volume/end systolic volume and ΔEF between groups with negative MPI results. For the positive MPI groups, there was no significant difference in all parameters, except for the change in end diastolic volume and change in end systolic volume after stress between both protocols. The Tl-201 provides comparable left-ventricular functional data to MIBI cardiac-gated single-photon emission computed tomography in patients with positive MPI results, and may therefore be undertaken routinely for incremental functional information that is especially valuable to this patient group. PMID:26678935

  8. Microimaging studies of myocardial substrate utilization and perfusion in two models of non-coronary heart disease

    SciTech Connect

    Som, P.; Oster, Z.H.; Knapp, F.F. Jr.

    1987-01-01

    We have studied two animal models of non-coronary heart disease. The salt-sensitive Dahl strain hypertensive rats and their genetically matched normotensive controls and the cardiomyopathic BIO 53.58 (CM) strain Syrian hamsters with age and sex-matched RB strain controls. The CM strain hamster seems to be a very good model of human congestive cardiomyopathy and the Dahl strain hypertensive rats have also been found to be good models for studying the effects of hypertension on the myocardium. In our studies we compared the utilization of various metabolic substrates, viz., fatty acids, glucose analogs, and the early distribution of /sup 201/Tl, as an indicator of myocardial flow. The routine studies involving dissection of animals for assaying the radioactivity following the injection of radiopharmaceuticals is not suitable for assessing regional changes in metabolism and flow. The use of quantitative autoradiographic microimaging (ARG) enables the visualization of discrete regional as well as global changes from normal and to quantitate them. This paper describes the methodology and results of these investigations. 14 refs., 5 figs.

  9. Effect of reconstruction parameters on defect detection in fan-beam SPECT

    NASA Astrophysics Data System (ADS)

    Gregoriou, George K.

    2002-05-01

    The effect of reconstruction parameters on the fan-beam filtered backprojection method in myocardial defect detection was investigated using an observer performance study and receiver operating characteristics (ROC) analysis. A mathematical phantom of the human torso was used to model the anatomy and Thallium-201 (Tl-201) uptake in humans. Half-scan fan-beam realistic projections were simulated using a low-energy high resolution (LEHR) collimator that incorporated the effects of photon attenuation, spatially varying detector response, scatter, and Poison noise. A focal length of 55 cm and a radius of rotation of 25 cm were used, which resulted to a magnification of two at the center of rotation and a maximum magnification of three in the reconstructed region of interest. By changing the reconstruction pixel size, five different projection bin width to reconstruction pixel size (PBWRPS) ratios were obtained which resulted in five classes of reconstructed images. Myocardial defects were simulated as Gaussian-shaped decreases in Tl-201 uptake distribution. The total projection count per 3 mm image slice was 44,000. A total of 96 reconstructed transaxial images from each one of the five classes were shown to eight observers for evaluation. The results indicate that the reconstruction pixel size has a significant effect on the quality of fan-beam SPECT images. Moreover, the study indicated that in order to ensure best image quality the PBWRPS ratio should be at least as large as the maximum possible magnification inside the reconstructed image array.

  10. Detection of cardiac allograft rejection using radionuclide techniques

    SciTech Connect

    Addonizio, L.J. )

    1990-09-01

    The results of the investigations in the search for a radionuclide technique to detect rejection have, thus far, not found any method that can be applied clinically. Functional studies are not sensitive enough, unless further work on the quantitative volume changes shows consistent correlation. Routine myocardial imaging agents such as {sup 67}Ga, {sup 99}TcPP, or the perfusion agent, {sup 201}Tl are clearly not specific enough to detect rejection until the grafts are nearly lost. Radiolabeled lymphocyte studies show promise, in that lymphocytes are intimately involved in the rejection process. However, there needs to be further research to determine if the specificity of the technique can isolate those patients who require treatment. The data involving labeled antimyosin antibody fragments indicate that they can specifically detect myocyte necrosis that occurs on the microscopic level. However, it may also be too sensitive a technique for transplanted hearts, which are so immunologically active at baseline to determine when treatment is necessary.30 references.

  11. Single-cell resolution mapping of neuronal damage in acute focal cerebral ischemia using thallium autometallography.

    PubMed

    Stöber, Franziska; Baldauf, Kathrin; Ziabreva, Iryna; Harhausen, Denise; Zille, Marietta; Neubert, Jenni; Reymann, Klaus G; Scheich, Henning; Dirnagl, Ulrich; Schröder, Ulrich H; Wunder, Andreas; Goldschmidt, Jürgen

    2014-01-01

    Neuronal damage shortly after onset or after brief episodes of cerebral ischemia has remained difficult to assess with clinical and preclinical imaging techniques as well as with microscopical methods. We here show, in rodent models of middle cerebral artery occlusion (MCAO), that neuronal damage in acute focal cerebral ischemia can be mapped with single-cell resolution using thallium autometallography (TlAMG), a histochemical technique for the detection of the K(+)-probe thallium (Tl(+)) in the brain. We intravenously injected rats and mice with thallium diethyldithiocarbamate (TlDDC), a lipophilic chelate complex that releases Tl(+) after crossing the blood-brain barrier. We found, within the territories of the affected arteries, areas of markedly reduced neuronal Tl(+) uptake in all animals at all time points studied ranging from 15 minutes to 24 hours after MCAO. In large lesions at early time points, areas with neuronal and astrocytic Tl(+) uptake below thresholds of detection were surrounded by putative penumbral zones with preserved but diminished Tl(+) uptake. At 24 hours, the areas of reduced Tl(+)uptake matched with areas delineated by established markers of neuronal damage. The results suggest the use of (201)TlDDC for preclinical and clinical single-photon emission computed tomography (SPECT) imaging of hyperacute alterations in brain K(+) metabolism and prediction of tissue viability in cerebral ischemia.

  12. Assessment of systolic thickening with thallium-201 ECG-gated single-photon emission computed tomography: A parameter for local left ventricular function

    SciTech Connect

    Mochizuki, T.; Murase, K.; Fujiwara, Y.; Tanada, S.; Hamamoto, K.; Tauxe, W.N. )

    1991-08-01

    The authors measured left ventricular (LV) systolic thickening expressed as a systolic thickening ratio in 28 patients, using 201Tl ECG-gated SPECT. Five normals, 15 patients with prior myocardial infarction, 5 with hypertrophic cardiomyopathy, and 3 with dilated cardiomyopathy were studied. The systolic thickening ratio was calculated as ((end-systolic--end-diastolic pixel counts) divided by end-diastolic pixel counts), using the circumferential profile technique of both end-diastolic and end-systolic short axial images. Functional images of the systolic thickening ratio were also displayed with the bull's-eye method. The mean systolic thickening ratio thus calculated were as follows: normals, 0.53 {plus minus} 0.05 (mean {plus minus} 1 s.d.); non-transmural prior myocardial infarction, 0.33 {plus minus} 0.09; transmural prior myocardial infarction, 0.14 {plus minus} 0.05; hypertrophic cardiomyopathy in relatively nonhypertrophied areas, 0.56 {plus minus} 0.11; hypertrophic cardiomyopathy in hypertrophied areas, 0.23 {plus minus} 0.07; and dilated cardiomyopathy, 0.19 {plus minus} 0.02. The systolic thickening ratio analysis by gated thallium SPECT offers a unique approach for assessing LV function.

  13. [Investigation of radioactivity measurement of medical radioactive waste].

    PubMed

    Koizumi, Kiyoshi; Masuda, Kazutaka; Kusakabe, Kiyoko; Kinoshita, Fujimi; Kobayashi, Kazumi; Yamamoto, Tetsuo; Kanaya, Shinichi; Kida, Tetsuo; Yanagisawa, Masamichi; Iwanaga, Tetsuo; Ikebuchi, Hideharu; Kusama, Keiji; Namiki, Nobuo; Okuma, Hiroshi; Fujimura, Yoko; Horikoshi, Akiko; Tanaka, Mamoru

    2004-11-01

    To explore the possibility of which medical radioactive wastes could be disposed as general wastes after keeping them a certain period of time and confirming that their radioactivity reach a background level (BGL), we made a survey of these wastes in several nuclear medicine facilities. The radioactive wastes were collected for one week, packed in a box according to its half-life, and measured its radioactivity by scintillation survey meter with time. Some wastes could reach a BGL within 10 times of half-life, but 19% of the short half-life group (group 1) including 99mTc and 123I, and 8% of the middle half-life group (group 2) including 67Ga, (111)In, and 201Tl did not reach a BGL within 20 times of half-life. A reason for delaying the time of reaching a BGL might be partially attributed to high initial radiation dose rate or heavy package weight. However, mixing with the nuclides of longer half-life was estimated to be the biggest factor affecting this result. When disposing medical radioactive wastes as general wastes, it is necessary to avoid mixing with radionuclide of longer half-life and confirm that it reaches a BGL by actual measurement.

  14. Hydrogenated amorphous silicon (a-Si:H) based gamma camera: Monte Carlo simulations

    SciTech Connect

    Lee, H.; Drewery, J.S.; Hong, W.S.; Jing, T.; Kaplan, S.N.; Mireshghi, A.; Perez-Mendez, V.

    1994-01-01

    A new gamma camera using a-Si:H photodetectors has been designed for the imaging of heart and other small organs. In this new design the photomultiplier tubes and the position sensing circuitry are replaced by 2-D array of a-Si:H p-i-n pixel photodetectors and readout circuitry which are built on a substrate. Without the photomultiplier tubes this camera is light weight, hence can be made portable. To predict the characteristics and the performance of this new gamma camera we did Monte Carlo simulations. In the simulations 128 {times} 128 imaging array of various pixel sizes were used. {sup 99m}Tc (140keV) and {sup 201}Tl(70keV) were used as radiation sources. From the simulations we could obtain the resolution of the camera and the overall system, and the blurring effects due to scattering in the phantom. Using the Wiener filter for image processing, restoration of the blurred image could be achieved. Simulation results of a-Si:H based gamma camera were compared with those of a conventional gamma camera.

  15. Calculation of lung-heart ratios for single-photon emission computed tomography

    SciTech Connect

    Soares, E.J.; King, M.A.; Glick, S.J.; Villegas, B.J.

    1996-06-01

    The authors investigate the effectiveness of simple iterative reconstruction techniques in calculating lung-heart activity ratios (LHRs). The LHR has been shown to be an effective indicator of the severity of coronary artery disease in cardiac SPECT. A study was conducted with a mathematical cardiac torso phantom that modelled uptake of {sup 201}Tl in the heart and lung regions. The projection data included only the effects of nonuniform photon attenuation. The data were first reconstructed with zeroth-order Chang and a variant of the Bellini method, both of which utilize information from the nonuniform attenuation map. This nonuniform (NU) Bellini method compensates exactly for attenuation in the heart region, but is incorrect for other regions in the medium. These reconstructions were then used as the initial estimates in the iterative Chang, variable step-size (VSS) Chang, and Morozumi methods,m for one and five iterations. The average heart count (AHC) and average lung count (ALC) were calculated using region-of-interest (ROI) templates derived from the true activity map. The population mean LHR was tabulated as the ratio of the ALC to AHC. Using the same reconstruction procedure, the authors also calculated the sample mean LHR and standard deviation from 21 noisy 3D reconstructions.

  16. Evaluation of radionuclide dose-calibrator measurements

    SciTech Connect

    Paras, P.; Comer, F.M.; Demeis, F.; Coursey, B.M.; Calhoun, J.M.; Golas, D.B.

    1986-01-01

    Performance data for radionuclide dose calibrators, which are primarily ionization chambers, are scarce. Large deviations have occasionally been reported, particularly for low photon energies, i.e., emissions from /sup 201/Tl, /sup 133/Xe. The volunteer user program (QB series) of the College of American Pathologists (CAP) (laboratory intercomparison quality control), supported by the US National Bureau of Standards (NBS), for quality control of dose calibrators was suspended. The Atomic Industrial Forum (AIF) has a quality control program among radiopharmaceutical manufacturers but there is no user program in the US at this time, and the performance of dose calibrators in the field is not known. In addition, a number of professionals expressed a strong feeling for the continuation of the CAP program and the availability of standards for dose calibrators from NBS. The objective of this study is twofold: (a) to evaluate the accuracy of dose calibrator measurements for individual patient radioactivity administered doses, and (b) to provide certified sources of certain radionuclides to calibrate the instruments for these radionuclides.

  17. Mitral valve prolapse in the ventriculogram: scintigraphic, electrocardiographic, and hemodynamic abnormalities

    SciTech Connect

    Tebbe, U.; Schicha, H.; Neumann, P.; Voth, E.; Emrich, D.; Neuhaus, K.L.; Kreuzer, H.

    1985-06-01

    Patients with mitral valve prolapse (MVP) frequently have chest pain, which may be difficult to differentiate from angina pectoris in coronary artery disease (CAD). The authors performed resting and exercise ECGs, pulmonary arterial pressure measurements, radionuclide ventriculography (/sup 99m/technetium), and perfusion scintigrams (/sup 201/thallium) in 56 patients with angiographically proven MVP and no CAD. Pathological results were obtained in 31% of exercise ECGs, 33% of pulmonary arterial pressure measurements during exercise, 22% of radionuclide ventriculographies, and in 75% of thallium perfusion scintigrams. A significant correlation in pathological results was found only between exercise ECG and both radionuclide ventriculography and pulmonary arterial pressure measurements. Because of the high prevalence of false-positive perfusion scintigrams in patients with typical or atypical chest pain, the use of exercise /sup 201/Tl imaging as a screening method to separate patients with MVP from those with CAD will not be appropriate. The variability of cardiac abnormalities in our patients with MVP and angiographically normal coronary arteries suggests that the MVP syndrome may represent a variable combination of metabolic, ischemic, or myopathic disorders.

  18. Myocardial scintigraphy with 201thallium in pediatric cardiology: A review of 52 cases

    SciTech Connect

    Bjoerkhem, G.E.; Evander, E.; White, T.; Lundstroem, N.R. )

    1990-01-01

    We report our experience of myocardial scintigraphy with 201thallium (201Tl) in 52 children, aged 4 days to 18 years, in which 80 studies were made primarily to demonstrate or exclude impaired myocardial perfusion. For analysis, the patients were divided into the following eight groups: group I, coronary artery malformations (five patients); group II, Kawasaki's syndrome (six patients); group III, arterial switch operation (seven patients); group IV, dilated cardiomyopathy (18 patients); group V, hypertrophic cardiomyopathy (four patients); group VI, myocardial dysfunction after surgery for congenital heart disease (five patients); group VII, pulmonary atresia (three patients); and group VIII, miscellaneous (four patients). Myocardial scintigraphy was performed with a planar or tomographic technique at rest or after exercise (four patients). Isotope-uptake defects, indicating impaired myocardial perfusion, were present in 14 patients, including small infants. Defects were seen in all groups except those with hypertrophic cardiomyopathy and pulmonary atresia. The absence of such defects in several of the patients with Kawasaki's syndrome was particularly valuable as it made coronary angiography unnecessary. In the other groups of patients myocardial scintigraphy was a valuable adjunct to other investigations.

  19. Effect of beta blockade on single photon emission computed tomographic (SPECT) thallium-201 images in patients with coronary disease

    SciTech Connect

    Narahara, K.A.; Thompson, C.J.; Hazen, J.F.; Brizendine, M.; Mena, I.

    1989-05-01

    We evaluated the effect of beta blockers on thallium-201 (Tl-201) single photon emission computed tomographic (SPECT) imaging in 12 patients with coronary disease using an automated computer algorithm. Maximal exercise heart rate and blood pressure were reduced and exercise time was increased with beta blockers. Estimated stress defect size decreased from 47 +/- 36.3 gm during placebo treatment to 32 +/- 27.1 gm during beta blocker therapy (-32%; p less than 0.01). The placebo treatment redistribution defect was estimated to be 28 +/- 29.8 gm. It fell to 15 +/- 23.3 gm with beta blockade (-46%; p less than 0.005). All patients had a stress Tl-201 defect during placebo treatment and eight had redistribution defects consistent with residual scar. During beta blocker therapy, 2 of 12 patients had normal stress-redistribution studies and only five patients had redistribution defects. Beta blockade can reduce exercise and redistribution Tl-201 SPECT defect size significantly while simultaneously increasing exercise time and reducing angina. Beta blockers may unmask or may eliminate evidence of redistribution. Tl-201 SPECT imaging may be useful in defining the reduction in ischemia produced by cardiac drugs.

  20. The Dos and Don'ts of how to Build a Planet, Using the Moon as an Example

    NASA Technical Reports Server (NTRS)

    Jones, J. H.

    2006-01-01

    The bulk chemical compositions of planets may yield important clues concerning planetary origins. Failing that, bulk compositions are still important, in that they constrain calculation of planetary mineralogies and also constrain the petrogenesis of basaltic magmas. In the case of the Earth, there is little or no debate about the composition of the Earth's upper mantle. This is because our sample collections contain peridotitic xenoliths of that mantle. The most fertile of these are believed to have been little modified from their primary compositions. Using these samples and chondritic meteorites as a starting point, small perturbations on the compositions of existing samples allow useful reconstruction of the bulk silicate Earth (BSE). Elsewhere, I have argued that the next simplest case is the Eucrite Parent Body (EPB). Reconstructions based on Sc partitioning indicate that the EPB can be well approximated by a mixture of 20% eucrite and 80% equilibrium olivine. This leads to a parent body that is similar to CO (or devolatilized CM) chondrites. Partial melting experiments on CM chondrites confirm this model, because the residual solids in these experiments are dominated by olivine with minor pigonite [3]. The most difficult bodies to reconstruct are those that have undergone the most differentiation. Both the Moon and Mars may have passed through a magma ocean stage. In any event, lunar and martian basalts, unlike eucrites, were not derived from undifferentiated source regions. Reconstructions are primarily based on compositional trends within the basalts themselves with some critical assumptions: (i) Refractory lithophile elements (Ca, Al, REE, actinides) are presumed to be in chondritic relative abundances; and (ii) some major element ratio is believed to exist in a chondritic ratio (e.g., Mg/Si, Mg/Al). The most commonly used parameter is Mg/Si.

  1. Computer Aided Drafting Packages for Secondary Education. Edition 2. PC DOS Compatible Programs. A MicroSIFT Quarterly Report.

    ERIC Educational Resources Information Center

    Pollard, Jim

    This report reviews eight IBM-compatible software packages that are available to secondary schools to teach computer-aided drafting (CAD). Software packages to be considered were selected following reviews of CAD periodicals, computers in education periodicals, advertisements, and recommendations of teachers. The packages were then rated by…

  2. Projeto do sistema anti-ressonante da fiação dos transdutores para o detector Mario Schenberg

    NASA Astrophysics Data System (ADS)

    Vieira, S. J.., Jr.; Melo, J. L.

    2003-08-01

    O detector de ondas gravitacionais Mario Schenberg está sendo projetado e construído pelo grupo Gráviton. Sua construção está ocorrendo no Laboratório de Estado Sólido e Baixas Temperaturas (LESBT) da Universidade de São Paulo, na cidade de São Paulo. Esse detector possui uma massa ressonante esférica de cobre-alumínio, com 65 cm de diâmetro, pesando aproximadamente 1150 Kg, suspensa por um sistema de isolamento vibracional, que se encontra em fase de testes preliminares. A real eficácia desse sistema, entretanto, só poderá ser comprovada quando o detector estiver aparelhado com, pelo menos, um transdutor eletromecânico de altíssima sensibilidade acoplado à massa ressonante. Neste momento, não só este sistema de isolamento vibracional será posto em teste, como o do projeto da fiação que transporta os sinais de microondas até os transdutores e destes para a pré-amplificação. Apesar dessa fiação ter sido projetada para não apresentar nenhum contato com a superfície esférica da antena, de maneira a não haver nenhuma transmissão de ruído vibracional do laboratório para esta, deve-se minimizar o ruído microfônico produzido nessa fiação por oscilações mecânicas, uma vez que ela não utiliza nenhum sistema de isolamento vibracional. Com o intuito de resolver este problema, projetamos uma estrutura, formada por pequenos cilindros conectados por barras, a qual não terá nenhuma ressonância mecânica na faixa de freqüências de interesse para detecção (3000 - 3400 Hz). Desta forma, as vibrações nessa faixa não serão amplificadas. O projeto foi feito usando iterativamente, de maneira a otimizar os resultados obtidos, o programa de elementos finitos Msc/Nastran. Através de simulações feitas neste programa, determinamos os parâmetros geométricos ideais a serem utilizados, os quais proporcionam a maior região espectral de interesse livre de ressonâncias.

  3. Cornell Produces a Video of Safety Dos and Don'ts for the YouTube Set

    ERIC Educational Resources Information Center

    Lipka, Sara

    2008-01-01

    Don't drink too much, download pirated files, light candles, or prop open doors. Warnings like those pervade the weighty work of admonition known as the student handbook. However, Allen J. Bova wonders, "Who ever reads that?" So Mr. Bova, director of risk management and insurance at Cornell University, tried to reach students with a video. This…

  4. GLOBAL CHANGE RESEARCH NEWS #9: ORD PROVIDES TECHNICAL SUPPORT TO EPA/OIA & DOS INITIATIVE IN EGYPT

    EPA Science Inventory

    This ninth edition reports on a workshop on global climate change that was held in Cairo, Egypt, on May 10-12, 1999. The workshop represented a successful partnership between EPA's Office of International Affairs, Office of Research and Development (ORD), Office of Air and Radiat...

  5. Buen Comienzo, Buen Futuro: El Bebe de Dos Meses (Healthy Start, Grow Smart: Your Two-Month-Old).

    ERIC Educational Resources Information Center

    Department of Education, Washington, DC.

    Distributed by the U.S. Departments of Agriculture, Education, and Health and Human Services, this Spanish-language pamphlet provides parents with information and advice about their infants in the second month of life. The pamphlet outlines typical infant behavior at 2 months of age, the need for regular visits to a physician, health insurance,…

  6. Hybrid Identity in Academic Writing: "Are There Two of Me?" (Identidad híbrida: "¿hay dos yo?")

    ERIC Educational Resources Information Center

    Crawford, Troy; Lengeling, Martha; Mora Pablo, Irasema; Heredia Ocampo, Rocío

    2014-01-01

    This paper explores the construction of identity in an academic learning environment in Central Mexico, and shows how identity may be linked to non-language factors such as emotions or family. These issues are associated with elements of hybrid identity. To analyze this we draw on language choice as a tool used for the construction of identity and…

  7. Cozinha: Um Lugar para a "bildung" dos Educadores (The Kitchen: A Place for the "bildung" of Educators).

    ERIC Educational Resources Information Center

    Damiano, Gilberto

    2000-01-01

    Uses a kitchen metaphor for philosophy of education, in dialogue with Augustine, Erasmus of Rotterdam, Brillat-Savarin, and others. Mixes and cooks ingredients in thinking: the centrality of the human being, corporeality, historicity, and transcendency; food as sign-symbol; eating-linguistic habits; educator-cook; space of the kitchen; sensuality,…

  8. (BARS) -- Bibliographic Retrieval System, Sandia Shock Compression (SSC) database Shock Physics Index (SPHINX). PC/DOS version 4.0

    SciTech Connect

    Herrmann, W.; Parker, T.J.; Mulholland, K.

    1993-09-01

    The Bibliographic Retrieval System (BARS) is a database management system specially designed to retrieve bibliographic references. Two databases are available, (i) the Sandia Shock Compression (SSC) database which contains over 5600 references to the literature related to stress waves in solids and their applications, and (ii) the Shock Physics Index (SPHINX) which includes over 6200 further references to stress waves in solids, material properties at intermediate and low rates, ballistic and hypervelocity impact, and explosive or shock fabrication methods. There is some overlap in the information in the two data bases.

  9. NGC 2849 y NGC 6134: dos cúmulos abiertos más para el proyecto BOCCE

    NASA Astrophysics Data System (ADS)

    Ahumada, A. V.; Bragaglia, A.; Cignoni, M.; Donati, P.; Tosi, M.; Marconi, G.

    The "Bologna Open Cluster Chemical Evolution" (BOCCE) project is a photometric and spectroscopic survey of Galactic open clusters (OCs), to be used as tracers of the properties and evolution of the Galactic disk. The main OCs parameters are derived in a precise and homogeneous way, and they will be used, for example, to determine the metallicity distribution in the Galactic disk and how it has evolved with time. We present here part of our last effort, concerning the photometric data obtained for NGC 2849 and NGC 6134. FULL TEXT IN SPANISH

  10. 76 FR 58074 - 30-Day Notice of Proposed Information Collection: DS-7001 and DS-7005, DOS-Sponsored Academic...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-19

    ..., DS-7005. Respondents: Applicants for the Academic Exchange Program. Estimated Number of Respondents: 7160 (For DS-7001, 3842 estimated; for DS-7005, 3318 estimated). Estimated Number of Responses: 7160 (For DS-7001, 3842 estimated; for DS-7005, 3318 estimated). Average Hours per Response: 0.75....

  11. 76 FR 25733 - 60-Day Notice of Proposed Information Collection: DS-7001 and DS-7005, DOS-Sponsored Academic...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-05

    .... Respondents: Applicants for the Academic Exchange Program. Estimated Number of Respondents: 7160 (For DS-7001, 3842 estimated; for DS-7005, 3318 estimated). Estimated Number of Responses: 7160 (For DS-7001, 3842 estimated; for DS-7005, 3318 estimated). Average Hours per Response: 0.75. Total Estimated Burden:...

  12. A new generation of real-time DOS technology for mission-oriented system integration and operation

    NASA Technical Reports Server (NTRS)

    Jensen, E. Douglas

    1988-01-01

    Information is given on system integration and operation (SIO) requirements and a new generation of technical approaches for SIO. Real-time, distribution, survivability, and adaptability requirements and technical approaches are covered. An Alpha operating system program management overview is outlined.

  13. The DOS 1 neutron dosimetry experiment at the HB-4-A key 7 surveillance site on the HFIR pressure vessel

    SciTech Connect

    Farrell, K.; Kam, F.B.; Baldwin, C.A.

    1994-01-01

    A comprehensive neutron dosimetry experiment was made at one of the prime surveillance sites at the High Flux Isotope Reactor (HFIR) pressure vessel to aid radiation embrittlement studies of the vessel and to benchmark neutron transport calculations. The thermal neutron flux at the key 7, position 5 site was found, from measurements of radioactivation of four cobalt wires and four silver wires, to be 2.4 {times} 10{sup 12} n{center_dot}m{sup {minus}2}{center_dot}s{sup {minus}1}. The thermal flux derived from two helium accumulation monitors was 2.3 {times} 10{sup 12} n{center_dot}m{sup {minus}2}{center_dot}{sup {minus}1}. The thermal flux estimated by neutron transport calculations was 3.7 {times} 10{sup 12} n{center_dot}m{sup {minus}2}s{sup {minus}1}. The fast flux, >1 MeV, determined from two nickel activation wires, was 1.5 {times} 10{sup 12} n{center_dot}m{sup {minus}2}{center_dot}s{sup {minus}1}, in keeping with values obtained earlier from stainless steel surveillance monitors and with a computed value of 1.2 {times} 10{sup 13} n{center_dot}m{sup {minus}2}{center_dot}{sup {minus}1}. The fast fluxes given by two reaction-product-type monitors, neptunium-237 and beryllium, were 2.6 {times} 10{sup 13} n{center_dot}m{sup {minus}2}{center_dot}s {sup {minus}1} and 2.2 {times} 10{sup 13} n{center_dot}m{sup {minus}2}s{sup {minus}1}, respectively. Follow-up experiments indicate that these latter high values of fast flux are reproducible but are false; they are due to the creation of greater levels of reaction products by photonuclear events induced by an exceptionally high ratio of gamma flux to fast neutron flux at the vessel.

  14. Clinical experience with technetium-99m teboroxime, a neutral, lipophilic myocardial perfusion imaging agent

    SciTech Connect

    Johnson, L.L.; Seldin, D.W. )

    1990-10-16

    Technetium-99m (Tc-99m) teboroxime is a new technetium-based myocardial perfusion imaging agent (investigational code = SQ30217 (Cardiotec, Squibb Diagnostics)). A member of a class of neutral, lipophilic, technetium-containing complexes known as boronic acid adducts of technetium dioxime (BATO) complexes, this agent is chemically very different from the cationic tracer thallium-201 (Tl-201) and from the cationic technetium complex Tc-99m sestamibi (Cardiolite, Du Pont Imaging Agents). Tc-99m teboroxime has high myocardial extraction, rapid blood clearance, little lung uptake and rapid myocardial washout. A biexponential pattern of myocardial washout is demonstrated in animals and in man. Effective half-lives of the 2 washout components in man are 5.2 minutes and 3.8 hours and represent approximately 66 and 33% of the myocardial activity, respectively. The first half-life for the myocardium is approximately 11 minutes. As the agent washes out of the heart, hepatic uptake occurs, peaking at about 5 minutes after injection. The liver is the major organ of excretion and receives, along with the large bowel, the largest radiation dose. Rapid imaging protocols using standard cameras have achieved good myocardial counts from 3 planar views acquired over a 4- to 5-minute period or for single photon emission computed tomography (SPECT) images acquired over a 10-minute period. An entire stress/rest procedure can be completed in 1 hour. Analysis of data from 155 patients from 4 centers using planar or SPECT imaging showed a sensitivity and specificity for blinded readings of 82 and 91%, respectively, when compared against overall clinical impression. 13 references.

  15. Myocardial perfusion imaging with technetium-99m sestamibi SPECT in the evaluation of coronary artery disease

    SciTech Connect

    Maddahi, J.; Kiat, H.; Van Train, K.F.; Prigent, F.; Friedman, J.; Garcia, E.V.; Alazraki, N.; DePuey, E.G.; Nichols, K.; Berman, D.S. )

    1990-10-16

    Technetium-99m (Tc-99m) sestamibi is a new myocardial perfusion imaging agent that offers significant advantages over thallium-201 (Tl-201) for myocardial perfusion imaging. The results of the current clinical trials using acquisition and processing parameters similar to those for Tl-201 and a separate (2-day) injection protocol suggest that Tc-99m sestamibi and Tl-201 single photon emission computed tomography (SPECT) provide similar information with respect to detection of myocardial perfusion defects, assessment of the pattern of defect reversibility, overall detection of coronary artery disease (CAD) and detection of disease in individual coronary arteries. Tc-99m sestamibi SPECT appears to be superior to Tc-99m sestamibi planar imaging because the former provides a higher defect contrast and is more accurate for detection of disease in individual coronary arteries. Research is currently under way addressing optimization of acquisition and processing of Tc-99m sestamibi studies and development of quantitative algorithms for detection and localization of CAD and sizing of transmural and nontransmural myocardial perfusion defects. It is expected that with the implementation of the final results of these new developments, further significant improvement in image quality will be attained, which in turn will further increase the confidence in image interpretation. Development of algorithms for analysis of end-diastolic myocardial images may allow better evaluation of small and nontransmural myocardial defects. Furthermore, gated studies may provide valuable information with respect to regional myocardial wall motion and wall thickening. With the implementation of algorithms for attenuation and scatter correction, the overall specificity of Tc-99m sestamibi SPECT should improve significantly. 32 references.

  16. Two Position Supine/Prone Myocardial Perfusion SPECT (MPS) Imaging Improves Visual Inter-Observer Correlation and Agreement

    PubMed Central

    Arsanjani, Reza; Hayes, Sean W.; Fish, Mathews; Shalev, Aryeh; Nakanishi, Rine; Thomson, Louise EJ; Friedman, John D; Germano, Guido; Berman, Daniel S.; Slomka, Piotr

    2014-01-01

    Objectives We aimed to compare the inter-observer agreement between two experienced readers using supine versus combined supine/prone myocardial perfusion SPECT (MPS) in a large population. Methods 1181 consecutive patients without known coronary artery disease (CAD) undergoing rest 201Tl/stress 99mTc-sestamibi MPS studies were evaluated. Visual reads were performed in 2 consecutive steps, with readers scoring the stress supine perfusion images during step 1 and rescoring the images using both supine/prone data during step 2. Visual summed stress scores (SSS) of 2 readers including regional scores in different vascular territories were compared. Results The specificity for both readers improved using combined supine/prone imaging (Reader 1: 92% vs. 86% [P=0.0002], Reader 2: 88% vs. 72% [P<0.0001]. The inter-observer correlation for SSS (0.90 vs. 0.84, P<0.0001) and inter-observer agreement for combined supine/prone reading (bias = 1.0, 95% confidence interval (CI) 0.9-1.2 vs. 3.1, 95% CI 2.8-3.4, P<0.0001) were significantly better than for supine-only reading. The overall correlation between SSS scores for two readers improved with supine/prone imaging for both genders, as well as in the left anterior descending and right coronary territories. New Knowledge Gained Combined supine/prone imaging improves overall inter-observer agreement as well as based on gender and vascular territories. Conclusion The inter-observer correlation and agreement significantly improves using two-position supine/prone versus supine-only imaging. PMID:24807622

  17. Assessment of systolic wall thickening using technetium-99m methoxyisobutylisonitrile in patients with coronary artery disease: relation to thallium-201 scintigraphy with re-injection.

    PubMed

    Nicolai, E; Cuocolo, A; Pace, L; Maurea, S; Nappi, A; Imbriaco, M; Morisco, C; Argenziano, L; Salvatore, M

    1995-09-01

    The results of resting planar ECG-gated technetium-99m methoxyisobutylisonitrile (99mTc-MIBI) imaging were compared with those of thallium-201 (Tl) re-injection after exercise-redistribution scintigraphy in 20 patients (19 men, 1 woman, mean age 53 +/- 10 years) with angiographically proven coronary artery disease. Eight normal subjects (seven men, one woman, mean age 50 +/- 8 years) constituted the control group. In these subjects, only resting 99mTc-MIBI imaging was performed. The standardized percent count increase from end-diastole to end-systole was calculated as an index of wall thickening in 13 segments for each study. Regional wall thickening index (WTI) and 99mTc-MIBI uptake were significantly different (P < 0.05) among segments classified as normal, reversible defects, irreversible defects with increased tracer uptake after re-injection (Re+) or irreversible defects with unchanged tracer uptake after re-injection (Re-) on Tl imaging. Furthermore, WTI and 99mTc-MIBI uptake were significantly higher (P < 0.05) in Re- segments with moderate reduction of Tl uptake (> or = 50% of peak activity) than in Re- segments with severe reduction of Tl uptake (< 50% of peak activity). A significant relationship between WTI and the results of Tl scintigraphy was observed (rho = 0.71, P < 0.0001). The percentage of Re- segments with severe reduction of WTI was significantly higher compared to Re+ segments (64% vs 3%, P < 0.01). Furthermore, compared with moderate Re- segments, a significantly higher percentage of severe Re- segments showed a severe reduction of WTI (86% vs 48%, P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

  18. Technetium-99m sestamibi uptake in human breast carcinoma cell lines displaying glutathione-associated drug-resistance.

    PubMed

    Kabasakal, L; Ozker, K; Hayward, M; Akansel, G; Griffith, O; Isitman, A T; Hellman, R; Collier, D

    1996-05-01

    An in vitro study was designed to evaluate the uptake of sestamibi (MIBI) in P-glycoprotein (Pgp) and glutathione-associated (GSH) multidrug-resistant (MDR) cell lines. MIBI uptake was studied in various human breast carcinoma cell lines, i.e. in wild-type (MCF7/wt) cells, in adriamycin-resistant (MCF7/adr) cells which express Pgp and in melphalan-resistant (MCF7/mph) cells with increased levels of GSH. The effects of buthiomine sulphoximine (BSO) and verapamil on MIBI uptake were also studied in the MCF7/mph and MCF7/adr cells respectively. The cells were incubated for 1 h with a dose of 0.1 MBq thallium-201 and technetium-99m MIBI. Both MIBI and 201Tl uptakes were higher for MCF7/mph cells than for the other cells studied. The mean MIBI uptake in MCF7/adr cells was significantly lower than that in MCF7/wt cells (1.9%+/-0.5% vs 3. 1%.0.6%; P <0.01). Verapamil treatment increased the MIBI uptake in MCF7/adr cells (to 2.6%.0.3%; P <0.05). Treatment of MCF7/mph cells with BSO resulted in a significant reduction in GSH content (from 243.2+/-81.1 nmol/mg protein to 17.6+/-4.4 nmol/mg protein; P <0. 001). However, MIBI uptake in BSO-treated and untreated MCF7/mph cells was similar (4.43%+/-0.5% and 5.93%+/-1.7%, respectively; P >0. 1). This study suggests that the uptake of MIBI is not diminished by glutathione-associated drug resistance and that MIBI uptake in a tumour sample does not necessarily indicate that a cancer is sensitive to drugs.

  19. Effect of an additional atropine injection during dobutamine infusion for myocardial SPET.

    PubMed

    Caner, B; Karanfil, A; Uysal, U; Tokgozoglu, L; Aksoyek, S; Ugur, O; Ciftci, I; Atalar, E; Kes, S; Bekdik, C

    1997-06-01

    The aim of this study was to examine the value of an additional atropine injection in patients who do not achieve an adequate heart rate during dobutamine infusion for myocardial perfusion SPET (single photon emission tomography). Patients undergoing dobutamine myocardial SPET who failed to achieve > or = 85% of their age-predicted maximal heart rate at the end of dobutamine infusion (D protocol) had a second dobutamine myocardial SPET study on a separate day with the addition of an atropine injection during the dobutamine infusion (D + A protocol). Twenty-nine patients were studied. 201Tl was used in 27 patients and 99Tc(m)-MIBI in two patients. All patients underwent coronary angiography and significant coronary artery disease was found in 19 of 29 patients. The mean heart rate obtained at the peak of dobutamine infusion in the D + A protocol was significantly higher than that in the D protocol (153.8 +/- 13.8 vs 117.5 +/- 15.3 beats min[-1]). The D + A protocol resulted in a higher diagnostic sensitivity for the detection of stenosed coronaries compared with the D protocol (87 vs 80%, P > 0.05) without changing the specificity (89% for both protocols). On the other hand, the frequency of side-effects and ECG changes during the D + A protocol was higher than that with the D protocol (32 vs 47). In conclusion, the addition of an atropine injection during dobutamine infusion resulted in a higher diagnostic sensitivity for identifying stenosed coronaries compared to dobutamine alone.

  20. Identification of Angiogenesis Rich-Viable Myocardium using RGD Dimer based SPECT after Myocardial Infarction

    PubMed Central

    Lee, Min Su; Park, Hyun Soo; Lee, Byung Chul; Jung, Jae Ho; Yoo, Jung Sun; Kim, Sang Eun

    2016-01-01

    Cardiac healing after myocardial ischemia is a complex biological process. Advances in understanding of wound healing response have paved the way for clinical testing of novel molecular imaging to improve clinical outcomes. A key factor for assessing myocardial viability after ischemic injury is the evaluation of angiogenesis accompanying increased expression of integrin αvβ3. Here, we describe the capability of an αvβ3 integrin-targeting SPECT agent, 99mTc-IDA-D-[c(RGDfK)]2, for identification of ischemic but viable myocardium, i.e., hibernating myocardium which is crucial to predict functional recovery after revascularization, the standard care of cardiovascular medicine. In vivo SPECT imaging of rat models with transient coronary occlusion showed significantly high uptake of 99mTc-IDA-D-[c(RGDfK)]2 in the ischemic region. Comparative measurements with 201Tl SPECT and 18F-FDG PET, then, proved that such prominent uptake of 99mTc-IDA-D-[c(RGDfK)]2 exactly matched the hallmark of hibernation, i.e., the perfusion-metabolism mismatch pattern. The uptake of 99mTc-IDA-D-[c(RGDfK)]2 was non-inferior to that of 18F-FDG, confirmed by time-course variation analysis. Immunohistochemical characterization revealed that an intense signal of 99mTc-IDA-D-[c(RGDfK)]2 corresponded to the vibrant angiogenic events with elevated expression of αvβ3 integrin. Together, these results establish that 99mTc-IDA-D-[c(RGDfK)]2 SPECT can serve as a sensitive clinical measure for myocardial salvage to identify the patients who might benefit most from revascularization. PMID:27283041

  1. Prognostic Value of Major Cardiac Event Risk Score Estimated With Gated Myocardial Perfusion Imaging in Japanese Patients With Coronary Artery Disease.

    PubMed

    Yoda, Shunichi; Nakanishi, Kanae; Tano, Ayako; Hori, Yusuke; Hayase, Misa; Mineki, Takashi; Suzuki, Yasuyuki; Matsumoto, Naoya; Hirayama, Atsushi

    2016-07-27

    We published a cardiac event risk score (CERS) predicting the risk of major cardiac events (MCEs) within 3 years. The purpose of this study was to verify the prognostic value of the CERS before and after treatment in Japanese patients with coronary artery disease.We retrospectively investigated 612 patients who underwent rest (201)Tl and stress (99m)Tc-tetrofosmin myocardial perfusion single photon emission computed tomography (SPECT) between October 2004 and March 2013 and who had a significant stenosis with ≥ 75% narrowing of the arterial diameter detected by coronary angiography performed after confirmation of ≥ 5% ischemia with the SPECT. The patients underwent treatment including revascularization and medication, and thereafter, were re-evaluated with SPECT during a chronic phase and followed-up to confirm prognosis for ≥ 1 year. The endpoint was the onset of MCEs during the follow-up.During the follow-up (36.7 ± 14.5 months), 50 patients (8.7%) experienced MCEs comprising cardiac death (n = 16), non-fatal myocardial infarction (n = 4), and unstable angina pectoris (n = 30). The multivariate Cox proportional hazards regression model analysis for the actual occurrence of MCEs showed the summed difference score % and MCE risks estimated with the CERS after treatment to be significant independent variables. Ischemic reduction after treatment contributed significantly to a decrease in the MCE risks. The MCE risks estimated with the CERS after treatment were generally consistent with the incidence of the MCEs actually observed.The CERS after treatment is a valuable formula for predicting prognosis in Japanese patients with coronary artery disease. PMID:27357436

  2. The utility of {sup 18}F-fluorodeoxyglucose positron emission tomography for early diagnosis of radiation-induced myocardial damage

    SciTech Connect

    Jingu, Keiichi . E-mail: kjingu-jr@rad.med.tohoku.ac.jp; Kaneta, Tomohiro; Nemoto, Kenji; Ichinose, Az; Oikawa, Minako; Takai, Yoshihiro; Ogawa, Yoshihiro; Nakata, Eiko; Sakayauchi, Toru; Takai, Kenji; Sugawara, Toshiyuki; Narazaki, Kakutaro; Fukuda, Hiroshi; Takahashi, Shoki; Yamada, Shogo

    2006-11-01

    Purpose: We evaluated the clinical significance of focal increased uptake in the basal myocardium on F-fluorodeoxyglucose positron emission tomography (FDG-PET) in patients with esophageal cancer after radiotherapy. Methods and Materials: Between August 2004 and July 2005, a total of 64 patients who had been irradiated for thoracic esophageal cancer underwent FDG-PET at least three months after the completion of chemoradiotherapy. Some patients showed increased FDG uptake in the basal portion of the myocardium. To clarify the clinical significance of these findings, further examinations of hearts were performed. The dose distribution in the myocardium with high FDG uptake was also analyzed retrospectively. Results: Thirteen (20.3%) of the 64 patients showed high FDG uptake in the basal myocardium corresponding to the irradiated fields compared with FDG uptake in the myocardium outside the irradiated fields. Eight of the 13 patients consented to undergo examinations of the heart. Five of those eight patients showed low {sup 123}I-BMIPP uptake and four showed low {sup 201}TlCl uptake in the myocardium corresponding with high FDG uptake regions. In two patients, delayed enhancement was found in some parts of the area with high FDG uptake on Gd-DTPA magnetic resonance imaging (MRI), and the delay-enhanced lesion showed hypokinesia on cine-MRI in one patient. Conclusions: FDG-PET often shows focal increased uptake in the basal myocardium after radiotherapy for esophageal cancer. This finding indicates the possibility of radiation-induced cardiac damage, and cardiac function and symptoms of such patients should be followed carefully.

  3. Assessment of radiation dose in nuclear cardiovascular imaging using realistic computational models

    SciTech Connect

    Xie, Tianwu; Lee, Choonsik; Bolch, Wesley E.; Zaidi, Habib

    2015-06-15

    Purpose: Nuclear cardiology plays an important role in clinical assessment and has enormous impact on the management of a variety of cardiovascular diseases. Pediatric patients at different age groups are exposed to a spectrum of radiation dose levels and associated cancer risks different from those of adults in diagnostic nuclear medicine procedures. Therefore, comprehensive radiation dosimetry evaluations for commonly used myocardial perfusion imaging (MPI) and viability radiotracers in target population (children and adults) at different age groups are highly desired. Methods: Using Monte Carlo calculations and biological effects of ionizing radiation VII model, we calculate the S-values for a number of radionuclides (Tl-201, Tc-99m, I-123, C-11, N-13, O-15, F-18, and Rb-82) and estimate the absorbed dose and effective dose for 12 MPI radiotracers in computational models including the newborn, 1-, 5-, 10-, 15-yr-old, and adult male and female computational phantoms. Results: For most organs, {sup 201}Tl produces the highest absorbed dose whereas {sup 82}Rb and {sup 15}O-water produce the lowest absorbed dose. For the newborn baby and adult patient, the effective dose of {sup 82}Rb is 48% and 77% lower than that of {sup 99m}Tc-tetrofosmin (rest), respectively. Conclusions: {sup 82}Rb results in lower effective dose in adults compared to {sup 99m}Tc-labeled tracers. However, this advantage is less apparent in children. The produced dosimetric databases for various radiotracers used in cardiovascular imaging, using new generation of computational models, can be used for risk-benefit assessment of a spectrum of patient population in clinical nuclear cardiology practice.

  4. Application of three-class ROC analysis to task-based image quality assessment of simultaneous dual-isotope myocardial perfusion SPECT (MPS).

    PubMed

    He, Xin; Song, Xiyun; Frey, Eric C

    2008-11-01

    The diagnosis of cardiac disease using dual-isotope myocardial perfusion SPECT (MPS) is based on the defect status in both stress and rest images, and can be modeled as a three-class task of classifying patients as having no, reversible, or fixed perfusion defects. Simultaneous acquisition protocols for dual-isotope MPS imaging have gained much interest due to their advantages including perfect registration of the (201)Tl and (99m)Tc images in space and time, increased patient comfort, and higher clinical throughput. As a result of simultaneous acquisition, however, crosstalk contamination, where photons emitted by one isotope contribute to the image of the other isotope, degrades image quality. Minimizing the crosstalk is important in obtaining the best possible image quality. One way to minimize the crosstalk is to optimize the injected activity of the two isotopes by considering the three-class nature of the diagnostic problem. To effectively do so, we have previously developed a three-class receiver operating characteristic (ROC) analysis methodology that extends and unifies the decision theoretic, linear discriminant analysis, and psychophysical foundations of binary ROC analysis in a three-class paradigm. In this work, we applied the proposed three-class ROC methodology to the assessment of the image quality of simultaneous dual-isotope MPS imaging techniques and the determination of the optimal injected activity combination. In addition to this application, the rapid development of diagnostic imaging techniques has produced an increasing number of clinical diagnostic tasks that involve not only disease detection, but also disease characterization and are thus multiclass tasks. This paper provides a practical example of the application of the proposed three-class ROC analysis methodology to medical problems.

  5. Identification of Angiogenesis Rich-Viable Myocardium using RGD Dimer based SPECT after Myocardial Infarction.

    PubMed

    Lee, Min Su; Park, Hyun Soo; Lee, Byung Chul; Jung, Jae Ho; Yoo, Jung Sun; Kim, Sang Eun

    2016-06-10

    Cardiac healing after myocardial ischemia is a complex biological process. Advances in understanding of wound healing response have paved the way for clinical testing of novel molecular imaging to improve clinical outcomes. A key factor for assessing myocardial viability after ischemic injury is the evaluation of angiogenesis accompanying increased expression of integrin αvβ3. Here, we describe the capability of an αvβ3 integrin-targeting SPECT agent, (99m)Tc-IDA-D-[c(RGDfK)]2, for identification of ischemic but viable myocardium, i.e., hibernating myocardium which is crucial to predict functional recovery after revascularization, the standard care of cardiovascular medicine. In vivo SPECT imaging of rat models with transient coronary occlusion showed significantly high uptake of (99m)Tc-IDA-D-[c(RGDfK)]2 in the ischemic region. Comparative measurements with (201)Tl SPECT and (18)F-FDG PET, then, proved that such prominent uptake of (99m)Tc-IDA-D-[c(RGDfK)]2 exactly matched the hallmark of hibernation, i.e., the perfusion-metabolism mismatch pattern. The uptake of (99m)Tc-IDA-D-[c(RGDfK)]2 was non-inferior to that of (18)F-FDG, confirmed by time-course variation analysis. Immunohistochemical characterization revealed that an intense signal of (99m)Tc-IDA-D-[c(RGDfK)]2 corresponded to the vibrant angiogenic events with elevated expression of αvβ3 integrin. Together, these results establish that (99m)Tc-IDA-D-[c(RGDfK)]2 SPECT can serve as a sensitive clinical measure for myocardial salvage to identify the patients who might benefit most from revascularization.

  6. Radioisotope Production for Medical and Physics Applications

    NASA Astrophysics Data System (ADS)

    Mausner, Leonard

    2012-10-01

    Radioisotopes are critical to the science and technology base of the US. Discoveries and applications made as a result of the availability of radioisotopes span widely from medicine, biology, physics, chemistry and homeland security. The clinical use of radioisotopes for medical diagnosis is the largest sector of use, with about 16 million procedures a year in the US. The use of ^99Mo/^99mTc generator and ^18F make up the majority, but ^201Tl, ^123I, ^111In, and ^67Ga are also used routinely to perform imaging of organ function. Application of radioisotopes for therapy is dominated by use of ^131I for thyroid malignancies, ^90Y for some solid tumors, and ^89Sr for bone cancer, but production of several more exotic species such as ^225Ac and ^211At are of significant current research interest. In physics ^225Ra is of interest for CP violation studies, and the actinides ^242Am, ^249Bk, and ^254Es are needed as targets for experiments to create superheavy elements. Large amounts of ^252Cf are needed as a fission source for the CARIBU experiment at ANL. The process of radioisotope production is multidisciplinary. Nuclear physics input based on nuclear reaction excitation function data is needed to choose an optimum target/projectile in order to maximize desired isotope production and minimize unwanted byproducts. Mechanical engineering is needed to address issues of target heating, induced mechanical stress and material compatibility of target and claddings. Radiochemists are involved as well since chemical separation to purify the desired final radioisotope product from the bulk target and impurities is also usually necessary. Most neutron rich species are produced at a few government and university reactors. Other radioisotopes are produced in cyclotrons in the commercial sector, university/hospital based facilities, and larger devices at the DOE labs. The landscape of US facilities, the techniques involved, and current supply challenges will be reviewed.

  7. Radio-decontamination efficacy and safety studies on optimized decontamination lotion formulation.

    PubMed

    Rana, S; Bhatt, S; Dutta, M; Khan, A W; Ali, J; Sultana, S; Kotta, S; Ansari, S H; Sharma, R K

    2012-09-15

    Objective of the present study was to optimize decontamination lotion and to evaluate its relative decontamination efficacy using three radio-isotopes (Technetium-99m, Iodine-131 and Thallium-201) as contaminants with varying length of contaminant exposure (0-1h). Experiments were performed on Sprague Dawley rat's intact skin and human tissue equivalent models. Rat's hair was removed by using depilator after trimming with scissors. Relative decontamination efficacy of the optimized lotion was investigated and compared with water as control. Static counts were recorded before and after decontamination using single photon emission computed tomography (SPECT). Measured decontamination efficacy (DE) values were analyzed using one way ANOVA and Student's t-test (p value<0.05) and were found statistically significant. Decontamination efficacy of the lotion was observed to be 90 ± 5%, 80 ± 2% and 85 ± 2%, for the (131)I, (201)Tl and (99m)Tc radio-contaminants respectively on skin. Reduced contaminant removal was recorded for the skin which was cleaned by depilator (50-60%). Skin decontamination was found more efficacious for rat skin decontamination than the human tissue equivalent model. Decontamination efficacy of the lotion against (99m)Tc was recorded 70 ± 15% at 0-1h on the tissue equivalent model. In vitro chelation efficacy of the lotion was also established by using the instant thin layer chromatography-slica gel (ITLC-SG) and >95% of (99m)Tc was recorded. Neither erythema nor edema was scored in the primary skin irritancy test visually observed for two weeks.

  8. Adenosine triphosphate stress echocardiography in the detection of myocardial ischemia.

    PubMed

    Fukai, T; Koyanagi, S; Tashiro, H; Ichiki, T; Tsutsui, H; Matsumoto, T; Takeshita, A

    1995-10-01

    The purpose of this study was to assess feasibility and safety in the diagnosis of coronary artery in the diagnosis of coronary artery disease and myocardial ischemia using adenosine triphosphate (ATP) stress echocardiography. ATP, a product of human myocardial tissue, is more potent than adenosine in increasing coronary blood flow. Like adenosine, ATP also has a short half-life (<10 s). Left ventricular echocardiograms were recorded during step-wise infusions of ATP in 86 patients who underwent coronary angiography and stress thallium 201 scintigraphy. No serious complications occurred with ATP infusion and most of the side effects were mild and transient. Significant coronary artery disease (>75% diameter stenosis) was present in 34 of 48 patients who had normal echocardiograms at rest. The sensitivity and specificity of ATP-induced wall motion abnormalities for coronary artery disease was 65% (22 of 34) and 100% (14 of 14), respectively. The sensitivity was 50% (10 of 20) in those with one-vessel disease and 86% (12 of 14) in those with multivessel disease (P < .05). In patients with normal echocardiograms at rest and without prior myocardial infarction, the sensitivity of ATP stress echocardiography for the detection of myocardial ischemia assessed by 201Tl single proton emission computed tomography was 58%, with a specificity of 76%, and a diagnostic accuracy of 66%. The sensitivity was 43% in those with one-vessel disease, and 86% in those with multivessel disease (P = .05). In patients with prior myocardial infarction, the sensitivity of ATP stress echocardiography for the detection of viable but jeopardized myocardium was 81%, with a specificity of 91%. The patients with well-developed collateral circulation had a higher incidence of developing wall motion abnormality than those without collaterals (70% v 40%, P < .01). ATP stress echocardiography is valuable for the assessment of coronary artery disease in patients with multivessel disease, coronary

  9. Identification of Angiogenesis Rich-Viable Myocardium using RGD Dimer based SPECT after Myocardial Infarction.

    PubMed

    Lee, Min Su; Park, Hyun Soo; Lee, Byung Chul; Jung, Jae Ho; Yoo, Jung Sun; Kim, Sang Eun

    2016-01-01

    Cardiac healing after myocardial ischemia is a complex biological process. Advances in understanding of wound healing response have paved the way for clinical testing of novel molecular imaging to improve clinical outcomes. A key factor for assessing myocardial viability after ischemic injury is the evaluation of angiogenesis accompanying increased expression of integrin αvβ3. Here, we describe the capability of an αvβ3 integrin-targeting SPECT agent, (99m)Tc-IDA-D-[c(RGDfK)]2, for identification of ischemic but viable myocardium, i.e., hibernating myocardium which is crucial to predict functional recovery after revascularization, the standard care of cardiovascular medicine. In vivo SPECT imaging of rat models with transient coronary occlusion showed significantly high uptake of (99m)Tc-IDA-D-[c(RGDfK)]2 in the ischemic region. Comparative measurements with (201)Tl SPECT and (18)F-FDG PET, then, proved that such prominent uptake of (99m)Tc-IDA-D-[c(RGDfK)]2 exactly matched the hallmark of hibernation, i.e., the perfusion-metabolism mismatch pattern. The uptake of (99m)Tc-IDA-D-[c(RGDfK)]2 was non-inferior to that of (18)F-FDG, confirmed by time-course variation analysis. Immunohistochemical characterization revealed that an intense signal of (99m)Tc-IDA-D-[c(RGDfK)]2 corresponded to the vibrant angiogenic events with elevated expression of αvβ3 integrin. Together, these results establish that (99m)Tc-IDA-D-[c(RGDfK)]2 SPECT can serve as a sensitive clinical measure for myocardial salvage to identify the patients who might benefit most from revascularization. PMID:27283041

  10. The routine use of sublingual GTN with resting 99Tcm-tetrofosmin myocardial perfusion imaging.

    PubMed

    Thorley, P J; Sheard, K L; Wright, D J; Sivananthan, U M

    1998-10-01

    Nitrates can be used to improve resting myocardial blood flow in patients with severe coronary artery disease. This may enhance tracer uptake during rest myocardial perfusion imaging. Recent studies using nitrates at rest have shown increased detection of reversible ischaemia in this patient group with the 201Tl and 99Tcm perfusion tracers MIBI and tetrofosmin. However, it is not always possible to assess the severity of coronary artery disease before the rest injection and therefore whether a patient would benefit from nitrate administration. To improve the sensitivity for the detection of reversible ischaemia and to avoid a repeat study with nitrates (especially in patients with 'fixed' defects), a protocol in which all patients routinely receive nitrates prior to the rest injection is required. This prospective study evaluated the effect of nitrate administration prior to rest imaging in a randomly selected group of patients. Thirty patients selected at random from routine referrals had stress, rest and rest + GTN tetrofosmin imaging on three separate days. Changes in reversibility between the rest and rest + GTN images were assessed both visually and using semi-quantitative analysis. Defects at stress were seen in 43 coronary artery territories, 33 of which were reversible at rest and 37 reversible at rest + GTN. Of these 43 defects, 82% demonstrated either increased or the same degree of reversibility at rest + GTN imaging compared to standard rest imaging. All defects with reduced reversibility at rest + GTN imaging (i.e. the remaining 18%) were, however, still reversible compared to the stress images. Some of this reduced reversibility may be due to attenuation artefacts. We conclude that the routine use of GTN with rest tetrofosmin imaging will result in increased detection of ischaemic areas with no loss of sensitivity or specificity.

  11. Effect of eating on thallium-201 myocardial redistribution after myocardial ischemia

    SciTech Connect

    Angello, D.A.; Wilson, R.A.; Palac, R.T.

    1987-09-01

    To determine whether eating a high-carbohydrate meal between initial and delayed postexercise thallium-201 (Tl-201) imaging affects detection of Tl-201 redistribution during exercise stress testing, 16 patients with stable angina performed 2 Tl-201 treadmill exercise stress tests within a 14-day interval. Immediately after initial postexercise imaging, patients either drank a commercially available instant breakfast preparation for the intervention test or drank an equivalent volume of water for the control test. Comparable exercise workloads were achieved by exercising patients to the same heart rate for both tests. The order of the 2 (intervention and control) tests were randomized. All patients had at least 1 region of Tl-201 myocardial redistribution on either their eating or control test scans, although only 7 of the 16 had positive treadmill exercise test responses. Forty-six regions showing Tl-201 myocardial redistribution were identified in all 144 regions examined. Significantly more of these regions were identified on control test scans than on eating test scans: 11 of 46 on both test scans, 6 of 46 only on eating test scans and 29 of 46 only on control scans (p less than 0.001). Consistent with results of the quantitative regional analysis, the percentage of Tl-201 clearance over 4 hours in the 46 Tl-201 myocardial redistribution regions was 39 +/- 8% for the eating tests and 29 +/- 8% for control tests (mean +/- standard deviation, p less than 0.003). In 4 patients diagnosis of transient ischemia would have been missed because their 14 Tl-201 myocardial redistribution regions were detected only on the control test scans.

  12. Ambient Dose Equivalent measured at the Instituto Nacional de Cancerologia Department of Nuclear Medicine

    SciTech Connect

    Avila, O.; Torres-Ulloa, C. L.; Medina, L. A.; Trujillo-Zamudio, F. E.; Gamboa de Buen, I.; Buenfil, A. E.; Brandan, M. E.

    2010-12-07

    Ambient dose equivalent values were determined in several sites at the Instituto Nacional de Cancerologia, Departmento de Medicina Nuclear, using TLD-100 and TLD-900 thermoluminescent dosemeters. Additionally, ambient dose equivalent was measured at a corridor outside the hospitalization room for patients treated with {sup 137}Cs brachytherapy. Dosemeter calibration was performed at the Instituto Nacional de Investigaciones Nucleares, Laboratorio de Metrologia, to known {sup 137}Cs gamma radiation air kerma. Radionuclides considered for this study are {sup 131}I, {sup 18}F, {sup 67}Ga, {sup 99m}Tc, {sup 111}In, {sup 201}Tl and {sup 137}Cs, with main gamma energies between 93 and 662 keV. Dosemeters were placed during a five month period in the nuclear medicine rooms (containing gamma-cameras), injection corridor, patient waiting areas, PET/CT study room, hot lab, waste storage room and corridors next to the hospitalization rooms for patients treated with {sup 131}I and {sup 137}Cs. High dose values were found at the waste storage room, outside corridor of {sup 137}Cs brachytherapy patients and PET/CT area. Ambient dose equivalent rate obtained for the {sup 137}Cs brachytherapy corridor is equal to (18.51{+-}0.02)x10{sup -3} mSv/h. Sites with minimum doses are the gamma camera rooms, having ambient dose equivalent rates equal to (0.05{+-}0.03)x10{sup -3} mSv/h. Recommendations have been given to the Department authorities so that further actions are taken to reduce doses at high dose sites in order to comply with the ALARA principle (as low as reasonably achievable).

  13. Comparison of rubidium-82 positron emission tomography and thallium-201 SPECT imaging for detection of coronary artery disease

    SciTech Connect

    Stewart, R.E.; Schwaiger, M.; Molina, E.; Popma, J.; Gacioch, G.M.; Kalus, M.; Squicciarini, S.; al-Aouar, Z.R.; Schork, A.; Kuhl, D.E. )

    1991-06-15

    The diagnostic performance of rubidium-82 (Rb-82) positron emission tomography (PET) and thallium-201 (Tl-201) single-photon emission-computed tomography (SPECT) for detecting coronary artery disease was investigated in 81 patients (52 men, 29 women). PET studies using 60 mCi of Rb-82 were performed at baseline and after intravenous infusion of 0.56 mg/kg dipyridamole in conjunction with handgrip stress. Tl-201 SPECT was performed after dipyridamole-handgrip stress and, in a subset of patients, after treadmill exercise. Sensitivity, specificity and overall diagnostic accuracy were assessed using both visually and quantitatively interpreted coronary angiograms. The overall sensitivity, specificity and accuracy of PET for detection of coronary artery disease (greater than 50% diameter stenosis) were 84, 88 and 85%, respectively. In comparison, the performance of SPECT revealed a sensitivity of 84%, specificity of 53% (p less than 0.05 vs PET) and accuracy of 79%. Similar results were obtained using either visual or quantitative angiographic criteria for severity of coronary artery disease. In 43 patients without prior myocardial infarction, the sensitivity for detection of disease was 71 and 73%, respectively, similar for both PET and SPECT. There was no significant difference in diagnostic performance between imaging modalities when 2 different modes of stress (exercise treadmill vs intravenous dipyridamole plus handgrip) were used with SPECT imaging. Thus, Rb-82 PET provides improved specificity compared with Tl-201 SPECT for identifying coronary artery disease, most likely due to the higher photon energy of Rb-82 and attenuation correction provided by PET. However, post-test referral cannot be entirely excluded as a potential explanation for the lower specificity of Tl-201 SPECT.

  14. Ambient Dose Equivalent measured at the Instituto Nacional de Cancerología Department of Nuclear Medicine

    NASA Astrophysics Data System (ADS)

    Ávila, O.; Torres-Ulloa, C. L.; Medina, L. A.; Trujillo-Zamudio, F. E.; de Buen, I. Gamboa; Buenfil, A. E.; Brandan, M. E.

    2010-12-01

    Ambient dose equivalent values were determined in several sites at the Instituto Nacional de Cancerología, Departmento de Medicina Nuclear, using TLD-100 and TLD-900 thermoluminescent dosemeters. Additionally, ambient dose equivalent was measured at a corridor outside the hospitalization room for patients treated with 137Cs brachytherapy. Dosemeter calibration was performed at the Instituto Nacional de Investigaciones Nucleares, Laboratorio de Metrología, to known 137Cs gamma radiation air kerma. Radionuclides considered for this study are 131I, 18F, 67Ga, 99mTc, 111In, 201Tl and 137Cs, with main gamma energies between 93 and 662 keV. Dosemeters were placed during a five month period in the nuclear medicine rooms (containing gamma-cameras), injection corridor, patient waiting areas, PET/CT study room, hot lab, waste storage room and corridors next to the hospitalization rooms for patients treated with 131I and 137Cs. High dose values were found at the waste storage room, outside corridor of 137Cs brachytherapy patients and PET/CT area. Ambient dose equivalent rate obtained for the 137Cs brachytherapy corridor is equal to (18.51±0.02)×10-3 mSv/h. Sites with minimum doses are the gamma camera rooms, having ambient dose equivalent rates equal to (0.05±0.03)×10-3 mSv/h. Recommendations have been given to the Department authorities so that further actions are taken to reduce doses at high dose sites in order to comply with the ALARA principle (as low as reasonably achievable).

  15. Alterations in myocardial metabolism and function at rest in stable angina pectoris: relations with the amount of exercise-induced thallium-201 perfusion defect

    SciTech Connect

    De Kock, M.; Melin, J.A.; Pouleur, H.; Rousseau, M.F.

    1986-01-01

    The relation between the amount of exercise-induced ischemia and alterations in left ventricular (LV) function and metabolism at rest was studied in 18 coronary patients with stable angina pectoris. An ischemic defect area score was computed from quantitative exercise thallium-201 (Tl-201) scintigraphy; this estimation of the amount of ischemic myocardium was used to classify the patients in group I (n = 8; score less than 15%, mean 6.7 +/- 2.5%) and II (n = 10; score greater than 15%; mean 27.2 +/- 8.9%). Hemodynamics and metabolism were studied in basal state. No patient had anginal pain during the study, and the extent of angiographic coronary artery disease (CAD) was comparable in the two groups. Heart rate, aortic pressure, coronary blood flow, and myocardial oxygen uptake were also similar in both groups. However, ejection fraction was reduced in group II (51 +/- 13 vs 63 +/- 5%; p less than 0.01) and LV relaxation was impaired as shown by the increase in time-constant of isovolumic pressure fall (55 +/- 16 vs 44 +/- 6 ms in group I; p less than 0.05); the LV end-diastolic pressure was also increased in group II (19 +/- 8 vs 10 +/- 4 mmHg in group l; p less than 0.05). Furthermore, in group II, myocardial lactate uptake was reduced (4 +/- 19 vs 30 +/- 29 mumole/min in group I; p less than 0.01) and the productions of alanine and glutamine were augmented (-7.5 +/- 4.4 vs -4.6 +/- 1.6 mumole/min in group I; p less than 0.05).

  16. Noninvasive assessment of changes in myocardial perfusion and ventricular performance following exercise training

    SciTech Connect

    Tubau, J.; Witztum, K.; Froelicher, V.; Jensen, D.; Atwood, E.; McKirnan, M.D.; Reynolds, J.; Ashburn, W.

    1982-08-01

    Seventeen coronary patients (CAD) underwent /sup 201/Tl treadmill and radionuclide (RNV) ejection fraction supine bicycle testing before and after 5.6 +/- 1.6 (mean +/- SD) months of an exercise program. Thallium data were assessed both using analog images and a computerized circumferential profile technique. Patients exercised on the treadmill to a higher workload after the exercise program, but achieved a similar pressure-rate product. When interpreting the analog thallium images, only 50% agreement was obtained for the assessment of changes in myocardial perfusion (pre/post-training). The computer technique, however, had low inter-intraobserver variability (6%) and better agreement (90.5%). Using the circumferential profile method, five patients improved (a total of 11 regions) and one patient worsened (with two regions). Before the exercise program, the ejection fraction (EF) response to supine bike exercise was normal (an increase greater than 11%) in four, flat in seven, and severely abnormal (a decrease of more than 4%) in six patients. After the exercise program, even though achieving similar or higher pressure-rate products, six patients improved their EF response, nine did not change, and two worsened. Of the five patients who improved their thallium images, one improved his EF response, two remained normal, and two did not change. One patient worsened both his thallium study and the EF response after the exercise program. Changes in thallium exercise images and the EF response to supine exercise occurred in our patients after an exercise program, but were not always concordant. Indeed, of five patients with exercise-induced ischemic ST changes before and after training, the EF response improved in three whereas myocardial perfusion was unchanged. Reasons for this lack of agreement are discussed, and have been considered in the planning of a randomized trial of the effects of an exercise program on myocardial perfusion and function.

  17. Noninvasive cardiac risk stratification of diabetic and nondiabetic uremic renal allograft candidates using dipyridamole-thallium-201 imaging and radionuclide ventriculography

    SciTech Connect

    Brown, K.A.; Rimmer, J.; Haisch, C. )

    1989-11-01

    The ability of noninvasive risk stratification using dipyridamole-thallium-201 (Tl-201) imaging and radionuclide ventriculography to predict perioperative and long-term cardiac events (myocardial infarction or cardiac death) was evaluated in 36 uremic diabetic and 29 nondiabetic candidates for renal allograft surgery. Of the 35 patients who underwent renal allograft surgery 8 +/- 7 months after the study, none had transient Tl-201 defects (although 13 had depressed left ventricular ejection fraction) and none developed perioperative cardiac events. During a mean follow-up of 23 +/- 11 months, 6 (9%) patients developed cardiac events. Logistic regression analysis was used to compare the predictive value of clinical data (including age, sex, diabetes, chest pain history, allograft recipient) and radionuclide data. Presence of transient Tl-201 defect and left ventricular ejection fraction were the only significant predictors of future cardiac events (p less than 0.01). No other patient variables, including diabetes or receiving a renal allograft, had either univariate or multivariate predictive value. All 3 patients with transient Tl-201 defects had cardiac events compared with only 3 of 62 (5%) patients without transient Tl-201 defect (p less than 0.0001). Mean left ventricular ejection fraction was lower in patients with cardiac events (44 +/- 13%) compared with patients without cardiac events (57 +/- 9%, p less than 0.005). Overall, 5 of 6 patients with cardiac events had either transient Tl-201 defects or depressed left ventricular ejection fraction. Dipyridamole-Tl-201 imaging and radionuclide ventriculography may be helpful in identifying uremic candidates for renal allograft surgery who are at low risk for perioperative and long-term cardiac events.

  18. Prevalence and clinical significance of residual myocardial ischemia 2 weeks after uncomplicated non-Q wave infarction: a prospective natural history study

    SciTech Connect

    Gibson, R.S.; Beller, G.A.; Gheorghiade, M.; Nygaard, T.W.; Watson, D.D.; Huey, B.L.; Sayre, S.L.; Kaiser, D.L.

    1986-06-01

    Despite having smaller infarct size and better left ventricular function, patients with non-Q wave myocardial infarction (NQMI) appear to have an unexpectedly high long-term mortality that is ultimately comparable to that of patients with Q-wave myocardial infarction (QMI). Patients with NQMI may lose their initial prognostic advantage because there is more viable tissue in the perfusion zone of the infarct-related vessel, rendering myocardium more prone to reinfarction. We tested this hypothesis in a prospective study of 241 consecutive patients 65 years of age or younger with acute uncomplicated myocardial infarction confirmed by creatine kinase levels (MB fraction). All patients received customary care and none underwent thrombolytic therapy or emergency angioplasty. Predischarge coronary angiography, radionuclide ventriculography, 24 hr Holter monitoring, and quantitative thallium-201 scintigraphy during treadmill exercise were performed 10 +/- 3 days after infarction. Infarcts were designated as QMI (n = 154) or NQMI (n = 87) by accepted criteria applied to serial electrocardiograms obtained on days 1, 2, 3, and 10. The baseline Norris coronary prognostic index, angiographic jeopardy scores, and prevalence of Lown grade ventricular arrhythmias were similar between groups despite evidence for less necrosis with NQMI vs QMI, reflected by lower peak creatine kinase levels (520 vs 1334 IU/liter; p = .0001, 4 hr sampling), higher resting left ventricular ejection fraction (53% vs 46%; p = .0001), fewer akinetic or dyskinetic segments (1.2 vs 2.4; p = .0001), and fewer persistent /sup 201/Tl defects in the infarct zone. Patients with NQMI also had more patent infarct-related vessels and a shorter time from onset of infarction to peak creatine kinase level.

  19. A software oscilloscope for DOS computers with an integrated remote control for a video tape recorder. The assignment of acoustic events to behavioural observations.

    PubMed

    Höller, P

    1995-12-01

    With only a little knowledge of programming IBM compatible computers in Basic, it is possible to create a digital software oscilloscope with sampling rates up to 17 kHz (depending on the CPU- and bus-speed). The only additional hardware requirement is a common sound card compatible with the Soundblaster. The system presented in this paper is built to analyse the direction a flying bat is facing during sound emission. For this reason the system works with some additional hardware devices, in order to monitor video sequences at the computer screen, overlaid by an online oscillogram. Using an RS232-interface for a Panasonic video tape recorder both the oscillogram and the video tape recorder can be controlled simultaneously and moreover be analysed frame by frame. Not only acoustical events, but also APs, myograms, EEGs and other physiological data can be digitized and analysed in combination with the behavioural data of an experimental subject.

  20. Environmental factors affecting the distribution of land snails in the Atlantic Rain Forest of Ilha Grande, Angra dos Reis, RJ, Brazil.

    PubMed

    Nunes, G K M; Santos, S B

    2012-02-01

    The distribution and abundance of terrestrial molluscs are affected by environmental factors, but data are lacking for Brazilian land snails. The aim of this study was to understand the relationship between measured environmental factors and the land-snail species composition of two hillsides covered with Atlantic Rain Forest on Ilha Grande. On each hillside, five plots located at 100 m intervals between 100 to 500 m asl were chosen. Each plot was sampled by carrying out timed searches and collecting and sorting litter samples from ten quadrats of 25 × 75 cm. A range of environmental data was measured for each of the quadrats in a plot. A Cluster Analysis was carried out for the richness and abundance data. The environmental variables were analysed using a Pearson Correlation Matrix and Discriminant Analysis. Our results show that the two mountains are similar in species richness, but species composition and abundance are different, probably reflecting observed differences in environmental conditions. The environmental factors associated with compositional variation between the two mountains were: atmospheric temperature, soil temperature, litter depth, and relative air humidity. Distinct luminosity and canopy closure conditions were related to the composition of the land-snail community of one hillside. PMID:22437388

  1. Yo Ciudadano: Un Curriculo de Experiencias para Educacion Civica. Nivel: Dos (Citizen Me: An Experiential Curriculum for Citizenship Education. Level: Two).

    ERIC Educational Resources Information Center

    Lantz, Jean

    Integrating concepts of basic citizenship education with community involvement, this experiential curriculum provides a means for developing decision making and critical thinking skills within the existing second grade social studies curriculum. The 10 lessons, translated into Spanish, cover the following concepts: friendly, unfriendly and…

  2. Neodymium, strontium and chromium isotopic studies of the LEW86010 and Angra dos Reis meteorites and the chronology of the angrite parent body

    NASA Technical Reports Server (NTRS)

    Nyquist, L. E.; Bansal, B.; Wiesmann, H.; Shih, C.-Y.

    1994-01-01

    Neodymium, stontium, and chromium isotopic studies of the LEW86010 angrite established its absolute age and the formation interval between its crystallization and condensation of Allende CAIs from the solar nebula. Pyroxene and phosphate were found to contain approximately 8% of its Sm and Nd inventory. A conventional Sm-147-Nd-143 isochron yielded an age of 4.53 +/- 0.04 Ga (2 sigma and Epsilon(sub Nd sup 143)) = 0.45 +/- 1.1. An Sm-146-Nd-142 isochron gives initial Sm-146/Sm-144 = 0.0076 +/- 0.0009 and Epsilon (sub Nd sup 142) = -2.5 +/- 0.4. The Rb-Sr analyses give initial Sr-87/Sr-86 Iota(sub Sr sup 87) = 0.698972 +/- 8 and 0.698970 +/- 18 for LEW and ADOR, respectively, relative to Sr-87/Sr-86 = 0.71025 for NBS987. The difference, Delta Iota(sub Sr Sup 87), between Iota (sub sr sup 87) for the angrites and literature values for Allende CAIs, corresponds to approximately Ma of growth in a solar nebula with a CI chondrite value of Rb-87/Sr-86 = 0.91, or approximately 5 Ma in a nebula with solar photospheric Rb-87/Sr-86 = 1.51. Excess Cr-53 from extinct Mn-53(t(sub 1/2) = 3.7 Ma)in LEW86010 corresponds to initial Mn-53/Mn-55 = 4.4 +/- 1.0 x 10(exp -5) for the inclusions as previously reported by the Paris group (Birck and Allegre, 1988). The Sm-146/Sm-144 value found for LEW86010 corresponds to solar system initial (Sm-146/Sm-144) = 0.0080 +/- 0.0009 for crystallization 8 Ma after Allende, the difference between Pb-Pb ages of angrites and Allende, or 0.0086 +/- 0.0009 for crystallation 18 Ma after Allende, using the Mn-Cr formation interval. The isotopic data are discussed in the context of a model in which an undifferentiated 'chondritic' parent body formed from the solar nebula approximately Ma after Allende CAIs and subsequently underwent differentiation accompanied by loss of volatiles. Parent bodies with Rb/Sr similar to that of CI, CM, or CO chondrites could satisfy the Cr and Sr isotopic systematics. If the angrite parent body had Rb/Sr similar to that of CV meteorites, it would have to form slightly later, approximately 2.6 Ma after the CAIs, to satisfy the Sr and CR isotopic systematics.

  3. Adolescentes que no habrían fumado pueden ser atraídos por los cigarrillos electrónicos

    Cancer.gov

    Artículo del blog Temas y relatos sobre un estudio reciente que sugiere que los adolescentes están usando cigarrillos electrónicos no solo como sustituto de cigarrillos convencionales sino cigarrillos electrónicos están atrayendo nuevos usuarios de tabaco

  4. A Educacao dos Portadores de Necessidades Especiais no Brasil no Periodo de 1910 a 1949 (Education of Those with Special Needs in Brazil from 1920 to 1949).

    ERIC Educational Resources Information Center

    Marques, Carlos Alberto; Santiago, Mylene Cristina; de Moura, Simone Moreira

    2000-01-01

    Examines education given to those with special needs in Brazil from 1910-1949. Shows the dichotomy of meanings in which the education of special needs persons during that period, besides being marked by concepts related to the exclusion paradigm, already indicated signs of respect for diversity and civil rights. (BT)

  5. Sanchez and Metz Elementary Schools: Dos Idiomas, Un Mundo. Dual Language Project. Title VII First-Year Evaluation Report, 1995-96.

    ERIC Educational Resources Information Center

    Ernest, Harishini M.; Gonzalez, Rosa Maria

    The first-year evaluation of a two-way Spanish/English bilingual education program at two Austin (Texas) elementary schools is presented. The developmental program has as its objectives the development of students' oral proficiency in Spanish and English, development of grade-level appropriate literacy in both languages, increase in academic…

  6. El Proyecto Cunningham: Dos Idiomas; Muchos Paises, 1995-96 (The Cunningham Project: Two Languages, Many Countries, 1995-96). Research Report on Educational Grants.

    ERIC Educational Resources Information Center

    Houston Independent School District, TX. Dept. of Research and Evaluation.

    This report presents an evaluation of a two-way bilingual program in English and Spanish at the Cunningham Elementary School (Texas). The program was designed to extend and expand educational reform by shifting the instructional program at the school over the 5-year time span from a transitional bilingual program to a two-way bilingual, or dual…

  7. Dos Idiomas, Un Mundo Dual Language Project Title VII Third-Year Evaluation Report, 1997-98. Publication Number 97.21.

    ERIC Educational Resources Information Center

    Liberty, Paul; Gonzalez, Rosa Maria

    An evaluation was conducted of the third year of a 5-year comprehensive bilingual education grant funded by Title VII of the Improving America's Schools Act of 1994. The grant funds a program of developmental bilingual education at two elementary schools in the Austin Independent School District (Texas). More than 25% of the students at each…

  8. En Busqueda de la Escuela del Siglo XXI: Dos Experiencias de Autoaprendizaje (In Search of the 21st Century School: Two Self-Learning Experiences).

    ERIC Educational Resources Information Center

    Schiefelbein, Ernesto; And Others

    This book is a contribution to the dialogue that is maintained today around the problems of education. The book contains four parts: (1) "In Search of the 21st Century School. Can the Colombian New School (EN) Show Us the Way?"; (2) "Experimentation with Self-Learning Materials in Two Schools in Conchali (Chile)"; (3) "Self-Learning Module for the…

  9. La investigacion sobre la calidad de los programas para ninos de hasta dos anos de edad (Research on Quality in Infant-Toddler Programs). ERIC Digest.

    ERIC Educational Resources Information Center

    Honig, Alice Sterling

    Concern about the quality of infant-toddler care programs has grown recently in response to two factors. The first is the need of employed parents for such care, and the second is research emphasizing the importance of brain development in the early years. This Spanish-language Digest introduces some of the many issues related to the quality of…

  10. 32 CFR Appendix C to Part 197 - Procedures for the Department of State (DoS) Foreign Relations of the United States (FRUS) Series

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) Foreign Relations of the United States (FRUS) Series C Appendix C to Part 197 National Defense Department... RESEARCH IN THE FILES OF THE OFFICE OF THE SECRETARY OF DEFENSE (OSD) Pt. 197, App. C Appendix C to Part... such non-DoD Agency classified information expected to be interfiled with the requested OSD records....

  11. How Do You Say "Twos" in Spanish, if "Two" Is "Dos"? Language as Means and Object in a Bilingual Kindergarten Classroom

    ERIC Educational Resources Information Center

    Mulvihill, Naomi

    2014-01-01

    In this essay Naomi Mulvihill uses vignettes from her bilingual kindergarten classroom to explore the dynamic processes by which young children make sense of language, focusing on instances in which she asks her students to compare texts presented in English and Spanish. Using Piaget's concept of disequilibrium as a guiding framework,…

  12. Análise da aplicação e dos resultados do modelo OPM3® para a área da saúde

    PubMed Central

    Augusto dos Santos, Luis; de Fátima Marin, Heimar

    2015-01-01

    Esta pesquisa procurou analisar se um modelo de questionário criado por uma comunidade internacional de gerenciamento de projetos e se é aplicavél a organizações voltadas a área de saúde. O modelo OPM3® (Organizational Project Management Maturity Model) foi criado para que organizações de qualquer área ou porte pudessem identificar a presença, ou ausência, de boas práticas de gerenciamento. O objetivo da aplicação desse modelo é avaliar sempre a organização e não o entrevistado. No presente artigo, são apresentados os resultados da aplicação desse modelo em uma organização que possuía produtos e serviços de tecnologia da informação aplicados à área de saúde. Este estudo verificou que o modelo é aplicável de forma rápida e que a organização analisada possuía um número expressivo de boas práticas. PMID:26924862

  13. Assessment of present and future radwaste generation in Saudi Arabia for the design of treatment and storage facilities

    SciTech Connect

    Abdul-Majid, S.; Kutbi, I.I.; Al-Marshad, A.I.

    1996-12-31

    Radwastes are produced in medical, industrial and educational institutions in Saudi Arabia. In medical centers many of the unsealed sources were low beta/gamma emitters of low radio-toxicity and less than about 4 months half-life. Significant radionuclides in this category were: {sup 99m}Tc, {sup 131}I, {sup 125}I, {sup 123}I, {sup 111}In, {sup 201}Tl, {sup 67}Ga and some of others. Longer lived sources such as {sup 57}Co, {sup 3}H, and {sup 14}C were also found in appreciable quantity. Delay and decay procedure followed by release to the sewerage or municipal landfill has been practiced for short-lived radwaste. Pretreatment and temporary storage were encouraged at large centers. Industrial sealed sources used primarily in radiography and well logging were mainly: {sup 60}Co, {sup 137}Cs, {sup 192}Ir, {sup 241}Am, {sup 241}Am-Be and {sup 252}Cf. It was agreed that radwastes whose half lives are above 138.4 days, the half life of {sup 210}Po, should be subject to conditioning treatment and permanent storage. It was anticipated that two main parameters affect the increase in radwaste in the future. The first is the increase of radionuclides use in hospitals in diagnosis and therapy in the country. The second is the increase in population which should be associated with increase in medical services in general. The annual long lived waste that need treatment, conditioning and storage as a function of time is expected to follow the relation: V= 10+0.48t{sup 2}, where V is the waste volume in m{sup 3} and t is the time in years after 1995. The expected long lived cumulative treated, conditioned, and liquid wastes in that year if not subject to volume reduction in m{sup 3} are expected to be: 500, 75, and 100 respectively. Comparisons were made with IAEA waste volume expectations for countries of similar conditions: the cumulative radwastes in m{sup 3} in 2020 are expected to be: 800, 125 and 175 respectively.

  14. [Acute effects of transdermal administration of nitroglycerin on effort tolerance and myocardial perfusion, evaluated by Tl-201 scintigraphy, in patients with stable effort angina].

    PubMed

    Novo, S; Liquori, M; Abrignani, M G; Giuliano, F; Panno, V; Fazio, M; Adamo, L; Corda, M; Indovina, A; di Maria, G

    1991-09-01

    downsloping, objective demonstration of myocardial ischemia. This antianginal and antiischemic effect might follow to the reduction of the preload induced by nitrates, in part also the reduction of the afterload, factors determining a decrease of the wall tension and so of MVO2, but also to a redistribution of the subendocardial flow as demonstrated by 201-Tl scintigraphic images. These effects induce also a global improvement of the left ventricular function as demonstrated by the reduction of the lung/heart index of thallium captation.

  15. A multiresolution restoration method for cardiac SPECT

    NASA Astrophysics Data System (ADS)

    Franquiz, Juan Manuel

    method was also assessed in 201Tl clinical SPECT studies. Phantom results demonstrated that the multiresolution algorithm compensated the liver spillover artifact, yielded uniform polar maps and improved significantly the accuracy in calculating myocardial defect size. The procedure does not require operator intervention and can be easily implemented in the clinical setting by using Fourier transform techniques. Finally, the extension of the multiresolution method to other SPECT procedures is discussed and recommended.

  16. Incremental Diagnostic Performance of Combined Parameters in the Detection of Severe Coronary Artery Disease Using Exercise Gated Myocardial Perfusion Imaging

    PubMed Central

    Liu, Chia-Ju; Wu, Yen-Wen; Ko, Kuan-Yin; Chen, Yi-Chieh; Cheng, Mei-Fang; Yen, Ruoh-Fang; Tzen, Kai-Yuan

    2015-01-01

    Purpose Myocardial perfusion imaging (MPI) using gated single-photon emission tomography (gSPECT) may underestimate the severity of coronary artery disease (CAD). This study aimed to evaluate the significance of combined parameters derived from gSPECT, as well as treadmill stress test parameters, in the detection of severe CAD. Methods A total of 211 consecutive patients referred for exercise MPI between June 2011 and June 2013 (who received invasive coronary angiography within six months after MPI) were retrospectively reviewed. Exercise MPI was performed with Bruce protocol and 201Tl injected at peak exercise. Gated SPECT was performed using a cadmium-zinc-telluride camera and processed by QPS/QGS software. Perfusion defect abnormalities such as sum stress score (SSS); sum difference score, algorithm-derived total perfusion deficits, transient ischemic dilatation ratios of end-diastolic volumes and end-systolic volumes, post-stress changes in ejection fraction, and lung/heart ratio (LHR) were calculated. Treadmill parameters, including ST depression (STD) at the 1st and 3rd minutes of recovery stage (1’STD and 3’STD), maximal STD corrected by heart rate increment (ST/HR), heart rate decline in 1st and 3rd minutes of recovery stage, recovery heart rate ratio (HR ratio), systolic and mean blood pressure ratios (SBP ratio and MAP ratio) during recovery phase were recorded. Diagnostic performances of these parameters were analyzed with receiver operating characteristic (ROC) analysis and logistic regression for detection of left main (≥ 50%) or 3-vessel disease (all ≥ 70% luminal stenosis) on invasive angiography. Results Among various MPI and treadmill parameters used for detection of severe CAD, SSS and ST/HR had the highest AUC (0.78, 0.73, p = NS) and best cut-off values (SSS > 6, ST/HR > 17.39 10-2mV/bpm), respectively. By univariate logistic regression, all parameters except 1’HRR, 3’HRR, SBP and MAP ratios increased the odds ratio of severe CAD

  17. Fine-Resolution Voxel S Values for Constructing Absorbed Dose Distributions at Variable Voxel Size

    PubMed Central

    Dieudonné, Arnaud; Hobbs, Robert F.; Bolch, Wesley E.; Sgouros, George; Gardin, Isabelle

    2010-01-01

    This article presents a revised voxel S values (VSVs) approach for dosimetry in targeted radiotherapy, allowing dose calculation for any voxel size and shape of a given SPECT or PET dataset. This approach represents an update to the methodology presented in MIRD pamphlet no. 17. Methods VSVs were generated in soft tissue with a fine spatial sampling using the Monte Carlo (MC) code MCNPX for particle emissions of 9 radionuclides: 18F, 90Y, 99mTc, 111In, 123I, 131I, 177Lu, 186Re, and 201Tl. A specific resampling algorithm was developed to compute VSVs for desired voxel dimensions. The dose calculation was performed by convolution via a fast Hartley transform. The fine VSVs were calculated for cubic voxels of 0.5 mm for electrons and 1.0 mm for photons. Validation studies were done for 90Y and 131I VSV sets by comparing the revised VSV approach to direct MC simulations. The first comparison included 20 spheres with different voxel sizes (3.8–7.7 mm) and radii (4–64 voxels) and the second comparison a hepatic tumor with cubic voxels of 3.8 mm. MC simulations were done with MCNPX for both. The third comparison was performed on 2 clinical patients with the 3D-RD (3-Dimensional Radiobiologic Dosimetry) software using the EGSnrc (Electron Gamma Shower National Research Council Canada)-based MC implementation, assuming a homogeneous tissue-density distribution. Results For the sphere model study, the mean relative difference in the average absorbed dose was 0.20% ± 0.41% for 90Y and −0.36% ± 0.51% for 131I (n = 20). For the hepatic tumor, the difference in the average absorbed dose to tumor was 0.33% for 90Y and −0.61% for 131I and the difference in average absorbed dose to the liver was 0.25% for 90Y and −1.35% for 131I. The comparison with the 3D-RD software showed an average voxel-to-voxel dose ratio between 0.991 and 0.996. The calculation time was below 10 s with the VSV approach and 50 and 15 h with 3D-RD for the 2 clinical patients. Conclusion This new

  18. Prevalence of high risk Tl-201 scintigraphic findings in patients with coronary artery disease: Relation to coronary anatomy and ECG stress test findings

    SciTech Connect

    Ryan, J.M.; Nygaard, T.W.; Gibson, R.S.; Gascho, J.A.; Watson, D.D.; Beller, G.A.

    1984-01-01

    The prevalence of a high risk exercise (Ex) Tl-201 (Tl) scintigram (scint) was determined in 295 consecutive patients (pts) with angiographic (angio) (>50% stenosis) coronary artery disease (CAD) and correlated with extent of CAD and Ex stress test findings. A high risk scint by quantitative criteria was defined as either: 1) a typical left main (LM) CAD pattern showing greater than or equal to 25% homogenous disease in Tl activity in septal and posterolateral walls; 2) a multivessel disease (MVD) pattern showing abnormal Tl uptake and/or washout in multiple vascular scan segments; 3) increased lung Tl uptake. The typical LMCAD pattern was observed in 6 of 43 pts (14%) with LMCAD compared to 2% of 53 pts with 3VD (p=0.03), 3% of 99 pts with 2VD (p=0.02) and 2% of 100 pts with 1VD (p-0.01). The MVD scint pattern was seen in 67% of pts with LMCAD compared to 49% (p=0.05) in 3VD pts, 41% (p=0.004) in 2VD pts and 24% (p=<0.0001) in 1VD pts. Prevalence of abnormal lung Tl was comparable in LMCAD (42%), 3VD (38%) and 2VD (34%) pts, but greater than observed in 1VD pts (26%; p=0.05). High risk ECG stress test was defined as 2 or more of: 1) >2.0 mm of ST decreasing; 2) greater than or equal to1.0 mm ST decreasing persisting >5 min post-EX; 3) ST decreasing at less than or equal to5 METS; 4) greater than or equal to10 mm Hg decreasing in Ex blood pressure. A high risk ECG stress test was observed in 58% of LMCAD pts compared to 32% of 3VD pts (p=0.009), 31% of 2VD pts (p=0.003) and 16% of 1VD pts (p<0.0001). Eighty-six % of LMCAD and 70% of 2 and 3VD pts had either a high risk Ex scint or stress test. Thus, EX Tl-201 scint appears useful in identifying high risk CAD pts.

  19. DIMED 86: Discurso dos Media e Ensino a Distancia = Discours des Media et Enseignement a Distance = Media Speech and Distance Teaching. Papers Presented at a Seminar (21st, Algarve, Portugal, March 10-15, 1986).

    ERIC Educational Resources Information Center

    Coelho, Maria Eduarda Leal

    Presentations at this seminar on distance education focused on the different types of speech in multimedia presentations which contribute to the elaboration (simulated or substituted) of a situation involving different relationships. In addition to opening and closing remarks by Marcel de Greve and a final report by the Scientific Committee of…

  20. Adenoviruses of canine and human origins in stool samples from free-living pampas foxes (Lycalopex gymnocercus) and crab-eating foxes (Cerdocyon thous) in São Francisco de Paula, Rio dos Sinos basin.

    PubMed

    Monteiro, G S; Fleck, J D; Kluge, M; Rech, N K; Soliman, M C; Staggemeier, R; Rodrigues, M T; Barros, M P; Heinzelmann, L S; Spilki, F R

    2015-05-01

    The spread of enteric viruses of domestic animals and human beings to wild species can be facilitated by the resistance of these viruses on the environment and their ability to be transmitted by water and contaminated food. The health status of the populations of pampas foxes Lycalopex gymnocercus) and crab-eating foxes (Cerdocyon thous) is largely unknown and the landscapes occupied by these animals in southern Brazil have been threatened by human occupation and expansion of agriculture. In this work, the search of genomes of human and canine adenoviruses in feces from these wild carnivores was used to track the dissemination of domestic animals and human pathogens to the free-living populations in a wildlife reserve located in southern Brazil. This was performed by virus-specific differential real-time polymerase chain reactions (qPCR) on stool specimens, avoiding capture and additional stress to the animals. Genus-specific conventional reverse-transcriptase PCR (RT-PCR) was complementarily performed aiming the detection of enteroviruses (EV) and rotaviruses (RV) on these same samples. HAdV genomes were found on 14 out of the 17 (82.35%) stool samples analysed, whereas CAV was found co-infecting 5 of these samples. RV genomes were detected on 7 of the 17 samples (41.18%) and all samples were negative for EV. The results point to the dispersion of HAdV and RV at a high rate to these species of South American wild carnivores, which can be an effect of growing anthropisation of the habitat of these animals.

  1. Observações simultâneas no óptico e infravermelho próximo dos BL Lacs PKS 2005-489 e PKS 2155-304 em diversas escalas de tempo

    NASA Astrophysics Data System (ADS)

    Dominici, T. P.; Abraham, Z.; Galo, A. L.

    2003-08-01

    A existência de variações rápidas de brilho em alguns blazares é um fenômeno bem comprovado, mas até agora não sabemos ao certo quais são os mecanismos físicos envolvidos. A maior dificuldade é a ausência de observações multibanda simultâneas que poderiam fornecer vínculos aos modelos. Buscando colaborar com a discussão estudamos o comportamento de dois BL Lacs, PKS 2005-489 e PKS 2155-304, em relação à variabilidade em diversas escalas de tempo, de poucos minutos até vários meses, com observações simultâneas em seis bandas espectrais (óptico e infravermelho próximo). Para tanto dois telescópios do LNA foram utilizados em conjunto nas campanhas observacionais realizadas em 2001 e 2002, cujos resultados são apresentados aqui. As duas fontes apresentaram características bastante diferentes, inclusive em relação à existência de variabilidade nos índices espectrais. Particularmente, registramos a primeira detecção de variações em escalas de tempo da ordem de poucos minutos em PKS 2005-489, com evidências da presença de um atraso entre as curvas de luz nas bandas V e R e a variação em R ocorrendo antes (o contrário do esperado no modelo de shock-in-jet). Em PKS 2155-304 detectamos pela primeira vez variabilidade em escalas de tempo de poucos minutos no infravermelho em um AGN. As observações indicam que as variações de brilho em blazares são o resultado da ação de mais de um fenômeno, especialmente em escalas de tempo muito curtas. Alguns cenários físicos são sugeridos para explicar os resultados observacionais.

  2. Linking the Modern and Recent Record of Cabo Frio Upwelling with Local Climate and Biogeochemical Processes in Hypersaline Coastal Lagoons, Região dos Lagos, Rio de Janeiro, Brazil

    NASA Astrophysics Data System (ADS)

    McKenzie, J. A.; Nascimento, G. S.; Albuquerque, A. L.; Belem, A. L.; Carreira, R.; Eglinton, T. I.; Vasconcelos, C.

    2015-12-01

    A unique marine and lagoonal system along the coast east of Rio de Janeiro is being investigated to understand the impact of climatic variability on the South Atlantic carbon cycle and biomineralisation processes involved in carbonate precipitation in the hypersaline coastal lagoons. The region is dominated by a semi-arid microclimate attributed to the local coastal upwelling phenomenon near Cabo Frio. The intensity of the upwelling affects the hydrology of the annual water and biogeochemical cycles in the lagoons, as well as biogeochemical signals of environmental change recorded in both onshore and offshore sediments. Preliminary results of δ18O and δD values of water samples collected monthly in Lagoa Vermelha and Brejo do Espinho from 2011 to 2014 show lower values for waters corresponding to the wet season, reflecting increased input of meteoric water. The higher values for waters collected during the dry season reflect the greater amount of evaporation with increased seasonal aridity. Radiocarbon dating of Holocene marine and lagoonal cores indicates that Mg-carbonate precipitation in the lagoons is associated with high evaporation. Modern field observations for the last 3 years suggest that the amount of carbonate precipitation is correlated with evaporitic conditions associated with the upwelling phenomenon. A calibration study of hydrogen isotopic fractionation in the modern lagoons is underway to define a relationship between δDlipid of suspended particles and δDwater of associated water. This isotopic relationship will be applied to material obtained in cores from the lagoons. Offshore cores will be studied using well-tested paleotemperature proxies to evaluate the intensity of the upwelling during the Holocene. In summary, linking the coastal upwelling with the lagoonal hydrology has the potential to furnish important insights about the relationship between the local climate and paleoceanographic circulation associated with the regional carbon cycle.

  3. Geochronology and Nd isotope geochemistry of the Gameleira Cu-Au deposit, Serra dos Carajás, Brazil: 1.8-1.7 Ga hydrothermal alteration and mineralization

    NASA Astrophysics Data System (ADS)

    Pimentel, Márcio M.; Lindenmayer, Zara G.; Laux, Jorge H.; Armstrong, Richard; de Araújo, Janice Caldas

    2003-01-01

    The Gameleira deposit is one of several important Cu-Au deposits associated with the late Archean (ca. 2.7 Ga) volcanic rocks of the Itacaiúnas supergroup in the Carajás mineral province, southeastern Pará. It comprises mainly biotite- and sulphide-rich veins and quartz-grunerite-biotite-gold hydrothermal veins that cut andesitic rocks. It is interpreted as representative of the Fe oxide Cu-Au class of deposit. Sm-Nd isotopic data indicate an age of 2719±80 Ma (MSWD=3.0) and ɛNd( T) of -1.4 for the host meta-andesites. Metavolcanic rocks and cogenetic gabbros give an age of 2757±81 Ma (1 σ) with ɛNd( T) of -0.8. This is considered the best estimate for the crystallization age of the Gameleira volcanic and subvolcanic rocks. Negative ɛNd( T) and Archean TDM model ages (mostly between 2.8 and 3.1 Ga) suggest some contamination with older crustal material. The andesitic/gabbroic rocks are cut by two generations of granite dykes. The older has striking petrographic and geochemical similarities to the ca. 1.87 Ga alkali-rich Pojuca granite, which is exposed a few kilometers to the northwest of the deposit. The younger is a leucogranite with a U-Pb SHRIMP age of 1583+9/-7 Ma. Neodymium isotopic analyses of the two generations of granites indicate a strong crustal affinity and possible derivation from reworking of the Archean crust. The quartz-grunerite-gold hydrothermal vein yields a Sm-Nd isochron (MSWD=.83) age of 1839±15 Ma (1 σ) with ɛNd( T) of -9.2. Pervasive potassic alteration, represented by the widespread formation of biotite in the country rocks, is dated by Ar-Ar at 1734±8 Ma, and a similar age of 1700±31 Ma (1 σ) is indicated by the Sm-Nd isochron for the biotite-sulphide veins. Similar to that for the quartz-grunerite vein, the ɛNd( T) value for the sulphide-rich veins is strongly negative (-8.2), thereby suggesting that the original fluids percolated through, leached, or were derived from igneous rocks with an Archaean Nd isotopic signature. The geochronological data suggest that the Gameleira Cu-Au mineralization is related to a Paleoproterozoic (ca. 1.83 Ga) episode of hydrothermal activity and is not Archaean. The younger ages of ca. 1.70-1.73 might be interpreted as products of the lower blocking temperatures of biotite in relation to the Ar-Ar and Sm-Nd isotopic systems. Combined with previous geochemistry and stable isotope data, the Nd isotopic data suggest that the mineralizing fluids were derived from, or strongly interacted with, a Paleoproterozoic crustal granite, possibly similar in age and composition to the Pojuca granite.

  4. [The occurrence of Biomphalaria straminea (Pulmonata: Planorbidae) on an aquaculture farm of IBAMA in Uberlândia, MG. Instituto Brasileiro do Meio Ambiente a dos Recursos Naturais Renováveis].

    PubMed

    Silveira, E de P; Marçal Júnior, O; Machado, M I

    1997-01-01

    This work evaluates the occurrence of freshwater snails in the IBAMA's fish breeding station in Uberlândia, Minas Gerais State. We verified the presence of Biomphalaria straminea in 39.5% of all breeding tanks. None of the snails were infected by Schistosoma mansoni, but further investigation should be done in the area.

  5. Adenoviruses of canine and human origins in stool samples from free-living pampas foxes (Lycalopex gymnocercus) and crab-eating foxes (Cerdocyon thous) in São Francisco de Paula, Rio dos Sinos basin.

    PubMed

    Monteiro, G S; Fleck, J D; Kluge, M; Rech, N K; Soliman, M C; Staggemeier, R; Rodrigues, M T; Barros, M P; Heinzelmann, L S; Spilki, F R

    2015-05-01

    The spread of enteric viruses of domestic animals and human beings to wild species can be facilitated by the resistance of these viruses on the environment and their ability to be transmitted by water and contaminated food. The health status of the populations of pampas foxes Lycalopex gymnocercus) and crab-eating foxes (Cerdocyon thous) is largely unknown and the landscapes occupied by these animals in southern Brazil have been threatened by human occupation and expansion of agriculture. In this work, the search of genomes of human and canine adenoviruses in feces from these wild carnivores was used to track the dissemination of domestic animals and human pathogens to the free-living populations in a wildlife reserve located in southern Brazil. This was performed by virus-specific differential real-time polymerase chain reactions (qPCR) on stool specimens, avoiding capture and additional stress to the animals. Genus-specific conventional reverse-transcriptase PCR (RT-PCR) was complementarily performed aiming the detection of enteroviruses (EV) and rotaviruses (RV) on these same samples. HAdV genomes were found on 14 out of the 17 (82.35%) stool samples analysed, whereas CAV was found co-infecting 5 of these samples. RV genomes were detected on 7 of the 17 samples (41.18%) and all samples were negative for EV. The results point to the dispersion of HAdV and RV at a high rate to these species of South American wild carnivores, which can be an effect of growing anthropisation of the habitat of these animals. PMID:26270208

  6. LETTERS TO THE EDITORS: Lightning ball: experiments on creation and hypotheses(comment on "Energy density calculations for ball-lightning-like luminous silicon balls" by G S Paiva, J V Ferreira, C C Bastos, M V P dos Santos, A C Pavão)

    NASA Astrophysics Data System (ADS)

    Shabanov, Gennadii D.

    2010-05-01

    The problems addressed in this paper include estimating: the energy density of luminous silicon balls, the density range of a natural lightning ball, and whether and how the object created and described in the commented paper (Usp. Fiz. Nauk 180 218 (2010) [Phys. Usp. 53 (2) 209 (2010)]) corresponds to the natural phenomenon.

  7. Reading: Students' Attitudes and Interests in Fourth, Fifth, and Sixth Grades in Official Portuguese Schools in the USA (A Leitura: Atitudes e Preferencias dos Educandos do 4th, 5th, e 6th Anos de Escolaridade nas Escolas Oficiais Portuguesas nos Estados Unidos da America).

    ERIC Educational Resources Information Center

    Castanho, Maria da Graca Borges

    A study investigated attitudes and preferences concerning reading among fourth-, fifth-, and sixth-grade students in Portuguese-language schools in the United States. Extrinsic factors influencing students (parents, teachers) were also analyzed. The research took place in 10 schools in 5 states. Data were obtained using questionnaires (students)…

  8. Lo que Piensan los Estudiantes y Profesores Sobre la Calidad de la Educacion Superior. Estudio Comparativo en 5 Instituciones de Educacion Superior--dos publicas y tres privadas--en Guadalajara, Jalisco, Mexico (What Students and Faculties Think about the Quality of Higher Education. Comparative Study of 5 Higher Education Institutions--Two Public and Three Private--in Guadalajara, Jalisco, Mexico).

    ERIC Educational Resources Information Center

    Yanez, Maria Lorena Hernandez

    This study, written in Spanish, compared attitudes of students (N=302) and faculty (N=28) at five institutions of higher education (two public and three private) in Guadalajara, Jalisco, Mexico. The study explored first, whether respondents believed there are significant quality differences between private and public universities and, second, what…

  9. Communicacion Expresiva: Como los ninos nos envian mensajes [and] Comunicacion Receptiva: Como los ninos entienden nuestros mensajes [and] Interacciones de Comunicacion: Hacen falta dos. Hojas informativa de DB-LINK (Communication Interactions: It Takes Two [and] Receptive Communication: How Children Understand Your Messages to Them [and] Expressive Communication: How Children Send Their Messages to You. DB-LINK Fact Sheets).

    ERIC Educational Resources Information Center

    Stremel, Kathleen

    This document consists of three separately published fact sheets combined here because of the close relationship of their subject matter. The first fact sheet, "Communication Interactions: It Takes Two" (Kathleen Stremel), defines communication; suggests ways to find opportunities for interactive communication; offers specific suggestions for…

  10. O Passado como Nacao: Imagens do Imperio nas Falas Reacionarias dos Anos 30 e 40 do Seculo XX: Uma Pequena Arqueologia do Debate Publico e Privado (The Past as Nation: Images of the Empire in the Reactionary Words of the 30s and 40s in the 20th Century: A Small Archaeology of the Public Debate versus the Private One).

    ERIC Educational Resources Information Center

    de Freitas, Marcos Cezar

    1998-01-01

    Suggests an archaeology of the public debate versus the private one in Brazil through analysis of the reactionary speech of a religious leader, Dom Jose Mauricio da Rocha, which produced innumerable representations of the Brazilian Empire. (PA)

  11. Whenever You Use a Computer You Are Using a Program Called an Operating System.

    ERIC Educational Resources Information Center

    Cook, Rick

    1984-01-01

    Examines design, features, and shortcomings of eight disk-based operating systems designed for general use that are popular or most likely to affect the future of microcomputing. Included are the CP/M family, MS-DOS, Apple DOS/ProDOS, Unix, Pick, the p-System, TRSDOS, and Macintosh/Lisa. (MBR)

  12. Software Reviews.

    ERIC Educational Resources Information Center

    Bitter, Gary G., Ed.

    1989-01-01

    Reviews three software packages: (1) "The Weather Machine Courseware Kit" for grades 7-12; (2) "Exploring Measurement, Time, and Money--Level I," for primary level mathematics; and (3) "Professor DOS with SmartGuide for DOS" providing an extensive tutorial covering DOS 2.1 to 4.0. Discusses the strengths and weaknesses of each package. (YP)

  13. Far tails of the density of states in amorphous organic semiconductors

    SciTech Connect

    Novikov, S. V.

    2015-10-28

    Far tails of the density of state (DOS) are calculated for the simple models of organic amorphous material, the model of dipolar glass and model of quadrupolar glass. It was found that in both models far tails are non-Gaussian. In the dipolar glass model, the DOS is symmetric around zero energy, while for the model of quadrupolar glass, the DOS is generally asymmetric and its asymmetry is directly related to the particular geometry of quadrupoles. Far tails of the DOS are relevant for the quasi-equilibrium transport of the charge carriers at low temperature. Asymmetry of DOS in quadrupolar glasses means a principal inequivalence of the random energy landscape for the transport of electrons and holes. Possible effect of the non-Gaussian shape of the far tails of the DOS on the temperature dependence of carrier drift mobility is discussed.

  14. Far tails of the density of states in amorphous organic semiconductors.

    PubMed

    Novikov, S V

    2015-10-28

    Far tails of the density of state (DOS) are calculated for the simple models of organic amorphous material, the model of dipolar glass and model of quadrupolar glass. It was found that in both models far tails are non-Gaussian. In the dipolar glass model, the DOS is symmetric around zero energy, while for the model of quadrupolar glass, the DOS is generally asymmetric and its asymmetry is directly related to the particular geometry of quadrupoles. Far tails of the DOS are relevant for the quasi-equilibrium transport of the charge carriers at low temperature. Asymmetry of DOS in quadrupolar glasses means a principal inequivalence of the random energy landscape for the transport of electrons and holes. Possible effect of the non-Gaussian shape of the far tails of the DOS on the temperature dependence of carrier drift mobility is discussed.

  15. Far tails of the density of states in amorphous organic semiconductors

    NASA Astrophysics Data System (ADS)

    Novikov, S. V.

    2015-10-01

    Far tails of the density of state (DOS) are calculated for the simple models of organic amorphous material, the model of dipolar glass and model of quadrupolar glass. It was found that in both models far tails are non-Gaussian. In the dipolar glass model, the DOS is symmetric around zero energy, while for the model of quadrupolar glass, the DOS is generally asymmetric and its asymmetry is directly related to the particular geometry of quadrupoles. Far tails of the DOS are relevant for the quasi-equilibrium transport of the charge carriers at low temperature. Asymmetry of DOS in quadrupolar glasses means a principal inequivalence of the random energy landscape for the transport of electrons and holes. Possible effect of the non-Gaussian shape of the far tails of the DOS on the temperature dependence of carrier drift mobility is discussed.

  16. Singularity of density of states induced by random bond disorder in graphene

    NASA Astrophysics Data System (ADS)

    Zhu, Lin; Wang, Xu

    2016-06-01

    We re-investigate the effect of random bond disorder on the density of states (DOS) in graphene. Our large-scale calculation supports that there exists a critical disorder value gbc dividing the DOS into two distinct structures. In the regime gb < gbc (gb is randomness of bond disorder), the DOS away from the Dirac point behaves like a power-law with positive exponent (α > 0): ρ (E) ∼ρ1 | E|α (E is Fermi energy with respect to the Dirac point, ρ1 is a constant). In the regime gb > gbc, it is observed that DOS develops a peak structure at the Dirac point E = 0. Through the finite-size scaling analysis, we elucidate that the DOS at the Dirac point diverges in the thermodynamics limit. Furthermore, it is found that the divergent behavior of DOS is sensitive to any on-site disorder which violates the chiral symmetry in graphene.

  17. Dissolved organic carbon and sulfur in southwestern Quebec lakes: Relationships with catchment and lake properties

    SciTech Connect

    Houle, D.; Carignan, R.; Lachance, M.

    1995-06-01

    In 59 southwestern Quebec lakes, dissolved organic S (DOS) concentration averages 185{+-}92 {mu}g liter{sup -1} (9.2% of total S) and ranges from undetectable to 437 {mu}g liter{sup -1} (22% of total S). DOS can be predicted from dissolved organic C (DOC) concentrations: DOS ({mu}g liter{sup -1}) = 2.20 log{sub 10}(DOC) + 7, r{sup 2} = 0.55. When applied to 1,238 lakes from five Quebec regions, this relationship indicates that DOS can account for 8.5% (Ottawa) to 22.2% (North Shore) of total S. These results stress the importance of evaluating DOS concentrations in studies of catchment S budgets. Multiple regression models using lake and catchment properties as independent variables respectively explain 75, 43, 49, and 69% of the variance in DOC, DOS, DOC: DOS, and color. The regressions found for DOC, color, and DOS include a flowpath index, accounting for dissolved organic matter (DOM) leaching from the catchment, and a term for in-lake losses. The DOC:DOS regression includes the flowpath index, lake perimeter, and altitude and suggests that DOM supply and composition also depend on catchment properties. 23 refs., 3 figs., 5 tabs.

  18. Single Photon Emission Computed Tomography for the Diagnosis of Coronary Artery Disease

    PubMed Central

    2010-01-01

    (201Tl) or technetium-99m (99mTc), or both, may be used to visualize the SPECT acquisition. Exercise or a pharmacologic agent is used to achieve stress. After the administration of the tracer, its distribution within the myocardium (which is dependent on myocardial blood flow) is imaged using a gamma camera. In SPECT imaging, the gamma camera rotates around the patients for 10 to 20 minutes so that multiple two-dimensional projections are acquired from various angles. The raw data are then processed using computational algorithms to obtain three-dimensional tomographic images. Since its inception, SPECT has evolved and its techniques/applications have become increasingly more complex and numerous. Accordingly, new techniques such as attenuation correction and ECG gating have been developed to correct for attenuation due to motion or soft-tissue artifact and to improve overall image clarity. Research Questions What is the diagnostic accuracy of SPECT for the diagnosis of CAD compared to the reference standard of CA? Is SPECT cost-effective compared to other non-invasive cardiac imaging modalities for the diagnosis of CAD? What are the major safety concerns with SPECT when used for the diagnosis of CAD? Methods A preliminary literature search was performed across OVID MEDLINE, MEDLINE In-Process and Other Non-Indexed Citations, EMBASE, the Cochrane Library, and the International Agency for Health Technology Assessment (INAHTA) for all systematic reviews/meta-analysis published between January 1, 2004 and August 22, 2009. A comprehensive systematic review was identified from this search and used as a basis for an updated search. A second comprehensive literature search was then performed on October 30, 2009 across the same databases for studies published between January 1, 2002 and October 30, 2009. Abstracts were reviewed by a single reviewer and, for those studies meeting the eligibility criteria, full-text articles were obtained. Reference lists were also hand

  19. Clearing a Path: The 16-Bit Operating System Jungle Offers Confusion, Not Standardization.

    ERIC Educational Resources Information Center

    Pournelle, Jerry

    1984-01-01

    Discusses the design and limited uses of the Pascal, MS-DOS, CP/M, and PC-DOS operating systems as standard operating systems for 16-bit microprocessors, especially with the more sophisticated microcomputers currently being developed. Advantages and disadvantages of Unix--a multitasking, multiuser operating system--as a standard operating system…

  20. The Challenges for Physicians of Demonstrating Continuing Competence in the Changing World of Medical Regulation: Osteopathic Pediatrician Case Report

    ERIC Educational Resources Information Center

    Langenau, Erik E.; Gimpel, John R.

    2012-01-01

    The current system of continuing medical education, maintenance of certification, and renewal of medical licenses can be quite burdensome and inefficient for all practicing physicians: medical doctors (M.D.s) and doctors of osteopathic medicine (D.O.s). D.O.s have opportunities for residency training and specialty certification which are not…

  1. 76 FR 5298 - Airworthiness Directives; Empresa Brasileira de Aeronautica S.A. (EMBRAER) Model EMB-500 Airplanes

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-31

    ... 12866; 2. Is not a ``significant rule'' under the DOT Regulatory Policies and Procedures (44 FR 11034... Support, Av. Brig. Farina Lima, 2170, Sao Jose dos Campos-- SP, CEP: 12227-901--PO Box: 36/2, BRASIL.... Farina Lima, 2170, Sao Jose dos Campos-SP, CEP: 12227-901--PO Box: 36/2, BRASIL; telephone: ++55 12...

  2. Choosing the Right Database Management Program.

    ERIC Educational Resources Information Center

    Vockell, Edward L.; Kopenec, Donald

    1989-01-01

    Provides a comparison of four database management programs commonly used in schools: AppleWorks, the DOS 3.3 and ProDOS versions of PFS, and MECC's Data Handler. Topics discussed include information storage, spelling checkers, editing functions, search strategies, graphs, printout formats, library applications, and HyperCard. (LRW)

  3. 78 FR 19077 - Forwarding of Asylum Applications to the Department of State

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-29

    ... removing the mandatory submission of all asylum applications to DOS. See 76 FR 67099 (Oct. 31, 2011). The... information relevant to the adjudication of a particular case or type of claims. By consolidating certain paragraphs, the final rule also removes redundant references to the types of information that DOS may...

  4. Dissolved organic sulfur in streams draining forested catchments in southern China.

    PubMed

    Wang, Zhanyi; Zhang, Xiaoshan; Wang, Zhangwei; Zhang, Yi; Li, Bingwen; Vogt, Rolf

    2012-01-01

    Dissolved organic sulfur (DOS) is an important fraction for sulfur mobilization in ecosystem. In this work stream waters were sampled in 25 forested sites in southern China to study the dissolved sulfur fractions. Dissolved sulfur was fractionated into dissolved organic sulfur (DOS) and inorganic sulfate (SO4(2-)) for 95 stream water samples. The results showed that the concentration of DOS ranged from 0 to 13.1 mg/L (average 1.3 mg/L) in all the streams. High concentrations of DOS in stream waters were found in the sites with high concentrations of sulfate. DOS constituted less than 60.1% of dissolved sulfur (average 17.9%). Statistical analysis showed that DOS concentration was correlated with SO4(2-) in streams waters and total sulfur in surface layer soils. The results also showed that DOS concentration in stream waters had a seasonal variation, but no trends were found with it. The implication was that the long term sulfur deposition had led the increase of the concentration and fraction of DOS in stream waters in acid rain prevailing regions

  5. Break up a File with EDLIN.

    ERIC Educational Resources Information Center

    Koga, James S.

    Online searchers who download large amounts of data into a single ASCII file often have difficulty fitting that large file into their MS-DOS word processors for post-processing. This paper gives step-by-step instructions for using EDLIN, a text editor for DOS files, to break up a large downloaded file into smaller files. (1 reference) (Author/EW)

  6. 75 FR 52581 - Notice of Meeting and Closed Meeting of the Cultural Property Advisory Committee

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-26

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF STATE [Public Notice 7105; Greece Docket No. DOS-2010-0339; Colombia Docket No. DOS-2010-0340] Notice of Meeting and Closed Meeting of the Cultural Property Advisory Committee There will be a meeting of the...

  7. Measuring Student Learning in Social Justice Courses: The Diversity and Oppression Scale

    ERIC Educational Resources Information Center

    Windsor, Liliane Cambraia; Shorkey, Clay; Battle, DuWayne

    2015-01-01

    The Diversity and Oppression Scale (DOS) is a standardized instrument measuring self-reported student learning about diversity and oppression based on requirements of the Council on Social Work Education. DOS was tested with social work students in 2 major North American universities. Factor structure was examined using exploratory factor analysis…

  8. Dissolved organic sulfur in streams draining forested catchments in southern China.

    PubMed

    Wang, Zhanyi; Zhang, Xiaoshan; Wang, Zhangwei; Zhang, Yi; Li, Bingwen; Vogt, Rolf

    2012-01-01

    Dissolved organic sulfur (DOS) is an important fraction for sulfur mobilization in ecosystem. In this work stream waters were sampled in 25 forested sites in southern China to study the dissolved sulfur fractions. Dissolved sulfur was fractionated into dissolved organic sulfur (DOS) and inorganic sulfate (SO4(2-)) for 95 stream water samples. The results showed that the concentration of DOS ranged from 0 to 13.1 mg/L (average 1.3 mg/L) in all the streams. High concentrations of DOS in stream waters were found in the sites with high concentrations of sulfate. DOS constituted less than 60.1% of dissolved sulfur (average 17.9%). Statistical analysis showed that DOS concentration was correlated with SO4(2-) in streams waters and total sulfur in surface layer soils. The results also showed that DOS concentration in stream waters had a seasonal variation, but no trends were found with it. The implication was that the long term sulfur deposition had led the increase of the concentration and fraction of DOS in stream waters in acid rain prevailing regions PMID:22894106

  9. Yours, Mine or Ours: What Counts as Innovation?

    ERIC Educational Resources Information Center

    Cooksey, Ray W.

    2011-01-01

    In this paper, I argue that research and development organizations (R&DOs) have particular perspectives on what counts as an innovation whereas the potential adopting users usually have quite different often diverse perspectives. If these "worldviews" do not overlap or speak to each other, then what R&DOs consider innovative might constitute a…

  10. MLJ Computer Corner.

    ERIC Educational Resources Information Center

    Brink, Dan

    1986-01-01

    A general technique for customizing computer printers (with the MS-DOS or PC-DOS software) to the special needs of foreign language professionals is described, and examples are presented. This "detour" technique can be used to turn the printer into a typewriter and send character sequences to the printer. (CB)

  11. 32 CFR Appendix B to Part 197 - Procedures for Historical Researchers Permanently Assigned Within the Executive Branch Working on...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... (CIA) and National Security Council (NSC) are not signatories to the Agreement. Authorization for... from the CIA, NSC, Department of State (DoS), and any other non-DoD Agency whose classified information... historian, authorization for access must be obtained from the CIA, NSC, DoS, and any other non-DoD...

  12. 32 CFR Appendix B to Part 197 - Procedures for Historical Researchers Permanently Assigned Within the Executive Branch Working on...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... (CIA) and National Security Council (NSC) are not signatories to the Agreement. Authorization for... from the CIA, NSC, Department of State (DoS), and any other non-DoD Agency whose classified information... historian, authorization for access must be obtained from the CIA, NSC, DoS, and any other non-DoD...

  13. 32 CFR Appendix B to Part 197 - Procedures for Historical Researchers Permanently Assigned Within the Executive Branch Working on...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... (CIA) and National Security Council (NSC) are not signatories to the Agreement. Authorization for... from the CIA, NSC, Department of State (DoS), and any other non-DoD Agency whose classified information... historian, authorization for access must be obtained from the CIA, NSC, DoS, and any other non-DoD...

  14. 32 CFR Appendix B to Part 197 - Procedures for Historical Researchers Permanently Assigned Within the Executive Branch Working on...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... (CIA) and National Security Council (NSC) are not signatories to the Agreement. Authorization for... from the CIA, NSC, Department of State (DoS), and any other non-DoD Agency whose classified information... historian, authorization for access must be obtained from the CIA, NSC, DoS, and any other non-DoD...

  15. 32 CFR Appendix B to Part 197 - Procedures for Historical Researchers Permanently Assigned Within the Executive Branch Working on...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... (CIA) and National Security Council (NSC) are not signatories to the Agreement. Authorization for... from the CIA, NSC, Department of State (DoS), and any other non-DoD Agency whose classified information... historian, authorization for access must be obtained from the CIA, NSC, DoS, and any other non-DoD...

  16. IBM Compatibility.

    ERIC Educational Resources Information Center

    Miller, Michael J.; McMillan, Tom

    1984-01-01

    Defines in detail the three levels of IBM compatibility--operational, data, and MS-DOS--and also examines 16-bit microprocessors and the MS-DOS operating system, both of which play key roles in determining whether a given machine will run IBM software. (MBR)

  17. Microcomputer Software for Online Information Management: An Overview.

    ERIC Educational Resources Information Center

    Nieuwenhuysen, Paul

    1988-01-01

    Summary of the findings of a critical overview of more than 200 microcomputer programs using PC-DOS/MS-DOS for online information management discusses software for telecommunications, conversion/reformatting, storage and retrieval of text information, and word processing. (6 references) (MES)

  18. A Bibliography of Text Information Management Software for IBM Microcomputers and Compatibles.

    ERIC Educational Resources Information Center

    Nieuwenhuysen, Paul

    1988-01-01

    This bibliography lists 754 books and articles which focus on programs that can run on IBM microcomputers and compatibles using PC DOS/MS DOS, and that can be used in online information and documentation work. An index lists the software packages alphabetically by title and references them to the main entries, which are listed by author. (CLB)

  19. RESPSYST: An Interactive Microcomputer Program for Education.

    ERIC Educational Resources Information Center

    Boyle, Joseph

    1985-01-01

    RESPSYST is a computer program (written in BASICA and using MS-DOS/PC-DOS microcomputers) incorporating more than 20 of the factors that determine gas transport by the cardio-respiratory system. The five-part program discusses most of these factors, provides several question/answer sections, and relies heavily on graphics to demonstrate…

  20. Effect of oxygen partial pressure on the density of states of amorphous InGaZnO thin-film transistors

    NASA Astrophysics Data System (ADS)

    Li, Jun; Huang, Chuan-Xin; Zhu, Wen-Qing; Zhang, Jian-Hua; Jiang, Xue-Yin; Zhang, Zhi-Lin; Li, Xi-Feng

    2016-10-01

    The thin-film transistors (TFTs) with InGaZnO active layer with different oxygen partial pressures are fabricated by radio frequency sputtering. The influence of the oxygen partial pressure on the density of states (DOS) for InGaZnO-TFT is investigated by using temperature-dependent field-effect measurements. It indicates that the DOS become smaller with increasing oxygen partial pressure. The results are verified by the threshold voltage shift of InGaZnO-TFT with different oxygen partial pressures. The trend of the variation of DOS is consistent with that of the threshold voltage shift for InGaZnO-TFT. Thus, the gate bias instability is attributed to the charge trapping mechanism based on DOS. Therefore, this work offered a brief and accurate method to calculate DOS for demonstrating the bias stability of transistor.

  1. If Your Child Learns in Two Languages: A Parent's Guide for Improving Educational Opportunities for Children Acquiring English as a Second Language = Si su nino aprende en dos idiomes: Una guia para que las familias sepan como mejorar las oportunidades educativas de los ninos que adquieren el ingles como segunda lengua = Neu lon Ban Hoc Bang Hai Thu Tieng: Chi-nam cua phu-huynh de cai tien co hoi hoc van cua con em dang hoc Anh van nhu sinh ngu thu hai.

    ERIC Educational Resources Information Center

    Zelasko, Nancy; Antunez, Beth

    This guide, in English, Spanish, and Vietnamese, aims to inform parents of students who have learned or are learning English as a Second Language about appropriate approaches for educating children so that they can work with schools to ensure a high quality education for their children. The emphasis is on explaining the laws, schools, and research…

  2. Photoelectric probing of the interfacial trap density-of-states in ZnO nanowire field-effect transistors.

    PubMed

    Raza, Syed Raza Ali; Lee, Young Tack; Chang, Youn-Gyoung; Jeon, Pyo Jin; Kim, Jae Hoon; Ha, Ryong; Choi, Heon-Jin; Im, Seongil

    2013-02-28

    We have fabricated transparent top-gate ZnO nanowire (NW) field effect transistors (FETs) on glass and measured their trap density-of-states (DOS) at the dielectric/ZnO NW interface with monochromatic photon beams during their operation. Our photon-probe method showed clear signatures of charge trap DOS at the interface, located near 2.3, 2.7, and 2.9 eV below the conduction band edge. The DOS information was utilized for the photo-detecting application of our transparent NW-FETs, which demonstrated fast and sensitive photo-detection of visible lights.

  3. Diversity oriented synthesis for novel anti-malarials.

    PubMed

    Bathula, Chandramohan; Singh, Shailja; Sen, Subhabrata

    2015-12-01

    Malaria a global pandemic has engulfed nearly 0.63 million people globally. It is high time that a cure for malaria is required to stop its ever increasing menace. Our commentary discusses the advent and contribution of diversity oriented synthesis (DOS) in the drug discovery efforts towards developing cure for malaria. DOS based on chemical genetics focusses on design and synthesis of molecular libraries which covers large tracts of biologically relevant chemical space. Herein we will discuss the applications, advantages, disadvantages and future directions of DOS with respect to malaria.

  4. Influence of fishing technique on organochlorine pesticide accumulation in fish and its possible human health risk in the Republic of Bénin.

    PubMed

    Yehouenou A Pazou, Elisabeth; Azehoun, Judicaël P; Ahoyo, Theodora; Aléodjrodo, Patrick Edorh; van Straalen, Nico M; van Gestel, Cornelis A M

    2013-09-01

    In Bénin different techniques are used for large-scale commercial fishing, Acadjas (enclosures constructed in the river) and Whédos (holes made in the river banks). This study aimed at assessing the extent of contamination related to these fishing techniques. Fish contained residues of DDT and its metabolites, α-endosulfan, dieldrin, aldrin, endrin and lindane. Pesticide levels were similar in fish from Acadjas and Whédos, except for higher α-endosulfan levels in fish from the Whédos. Comparing pesticide intake levels through fish consumption with tolerable daily intake levels showed that in all cases risk for human health is low.

  5. Vibrational Properties of Nanograins and Interfaces in Nanocrystalline Materials

    SciTech Connect

    Stankov, S.; Sergueev, I.; Chumakov, A. I.; Rueffer, R.; Yue, Y. Z.; Hu, L.; Miglierini, M.; Sepiol, B.; Svec, P.

    2008-06-13

    The vibrational dynamics of nanocrystalline Fe{sub 90}Zr{sub 7}B{sub 3} was studied at various phases of crystallization. The density of phonon states (DOS) of the nanograins was separated from that of the interfaces for a wide range of grain sizes and interface thicknesses. The DOS of the nanograins does not vary with their size and down to 2 nm grains still closely resembles that of the bulk. The anomalous enhancement of the phonon states at low and high energies originates from the DOS of the interfaces and scales linearly to their atomic fraction.

  6. Disorder-induced gap in the normal density of states of the organic superconductor κ-(BEDT-TTF)2Cu[N(CN)2]Br.

    PubMed

    Diehl, Sandra; Methfessel, Torsten; Tutsch, Ulrich; Müller, Jens; Lang, Michael; Huth, Michael; Jourdan, Martin; Elmers, Hans-Joachim

    2015-07-01

    The local density of states (DOS) of the organic superconductor κ-(BEDT-TTF)2Cu[N(CN)2]Br, measured by scanning tunneling spectroscopy on in situ cleaved surfaces, reveals a logarithmic suppression near the Fermi edge persisting above the critical temperature T(c). The experimentally observed suppression of the DOS is in excellent agreement with a soft Hubbard gap as predicted by the Anderson-Hubbard model for systems with disorder. The electronic disorder also explains the diminished coherence peaks of the quasi-particle DOS below T(c).

  7. Sore Throat? Know When To Call the Doctor

    MedlinePlus

    ... be. According to Phillip L. Accardo, DO, an osteopathic physician from Lee’s Summit, Mo., the key to treating ... does not support this functionality. About Osteopathic Medicine Osteopathic physicians, or DOs, are fully licensed to prescribe medicine ...

  8. 8. General oblique view: east side of south end, from ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. General oblique view: east side of south end, from the Dos Hermanos Highway Bridge - Puente Guillermo Esteves, Spanning San Antonio Channel at PR-25 (Juan Ponce de Leon Avenue), San Juan, San Juan Municipio, PR

  9. Doctor of osteopathic medicine

    MedlinePlus

    ... within the specialty area and passing the board certification exams. DOs practice in all specialties of medicine, ... 2014;114:200-212. Kuchera ML. Applying osteopathic principles to formulate treatment for patients with chronic pain. ...

  10. Ensuring Safe Use of Contact Lens Solution

    MedlinePlus

    ... For Consumers Consumer Updates Ensuring Safe Use of Contact Lens Solution Share Tweet Linkedin Pin it More ... back to top Dos and Don'ts for Contact Lens Wearers DO: Always wash your hands before ...

  11. 76 FR 7511 - Airworthiness Directives; Empresa Brasileira de Aeronautica S.A. (EMBRAER) Model ERJ 170...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-10

    ... rule'' under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and 3. Will.... Brigadeiro Faria Lima, 2170--Putim-- 12227-901 S o Jose dos Campos--SP--BRASIL; telephone +55 12 3927-5852...

  12. 76 FR 2279 - Airworthiness Directives; Empresa Brasileira de Aeronautica S.A. (EMBRAER) Model ERJ 170 and ERJ...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-13

    ... rule'' under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and 3. Will.... Brigadeiro Faria Lima, 2170-Putim- 12227-901 S o Jose dos Campos-SP--BRASIL; telephone +55 12 3927- 5852...

  13. 75 FR 9814 - Airworthiness Directives; Empresa Brasileira de Aeronautica S.A. (EMBRAER) Model ERJ 190-100 STD...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-04

    ... Policies and Procedures (44 FR 11034, February 26, 1979); and 3. Will not have a significant economic.... Brigadeiro Faria Lima, 2170--Putim-- 12227-901 S o Jose dos Campos--SP--BRASIL; telephone: +55 12...

  14. "The World in a Drop of Water": The Feminist Vision of Patricia Howell.

    ERIC Educational Resources Information Center

    Holmlund, Chris

    1993-01-01

    Discusses two films ("Dos veces mujer" and "Intima raiz") of Patricia Howell. Demonstrates how thoroughly the feminist themes Howell's films weave together around motherhood are inflected by the specific Latin American and Costa Rican contexts in which she works. (RS)

  15. 77 FR 39320 - Suggestions for Environmental Cooperation Pursuant to the United States-Singapore Memorandum of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-02

    ... comment on this notice by going to: http://www.regulations.gov/#!home and searching on docket number: DOS...; (2) participating in regional initiatives on environmentally sustainable cities and...

  16. Microscopist`s aide: A computer program written to analyze TEM micrographs

    SciTech Connect

    Reinhart, D.E.; Gelles, D.S.

    1996-04-01

    A computer program has been rewritten in DOS Basic allowing current state-of-the-art computer equipment to be used for quantitative measurement of microstructural features such as voids, dislocations, and precipitates.

  17. 48 CFR 602.101-70 - DOSAR definitions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Agency. Department or DOS means the Department of State, including all of its activities wherever located... within its specific geographic area as assigned by the Office of Logistics Operations. There are...

  18. Computer Viruses: An Overview.

    ERIC Educational Resources Information Center

    Marmion, Dan

    1990-01-01

    Discusses the early history and current proliferation of computer viruses that occur on Macintosh and DOS personal computers, mentions virus detection programs, and offers suggestions for how libraries can protect themselves and their users from damage by computer viruses. (LRW)

  19. An Expert System for Identification of Minerals in Thin Section.

    ERIC Educational Resources Information Center

    Donahoe, James Louis; And Others

    1989-01-01

    Discusses a computer database which includes optical properties of 142 minerals. Uses fuzzy logic to identify minerals from incomplete and imprecise information. Written in Turbo PASCAL for MS-DOS with 128K. (MVL)

  20. Density of photon states in dye-doped chiral nematic liquid crystal cells in the presence of losses and gain.

    PubMed

    Mavrogordatos, Th K; Morris, S M; Castles, F; Hands, P J W; Ford, A D; Coles, H J; Wilkinson, T D

    2012-07-01

    We calculate the density of photon states (DOS) of the normal modes in dye-doped chiral nematic liquid crystal (LC) cells in the presence of various loss mechanisms. Losses and gain are incorporated into the transmission characteristics through the introduction of a small imaginary part in the dielectric constant perpendicular and along the director, for which we assume no frequency dispersion. Theoretical results are presented on the DOS in the region of the photonic band gap for a range of values of the loss coefficient and different values of the optical anisotropy. The obtained values of the DOS at the photonic band gap edges predict a reversal of the dominant modes in the structure. Our results are found to be in good agreement with the experimentally obtained excitation thresholds in chiral nematic LC lasers. The behavior of the DOS is also discussed for amplifying LC cells providing additional insight to the lasing mechanism of these structures.

  1. 48 CFR 602.101-70 - DOSAR definitions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Agency. Department or DOS means the Department of State, including all of its activities wherever located... within its specific geographic area as assigned by the Office of Logistics Operations. There are...

  2. Computers in Schools.

    ERIC Educational Resources Information Center

    Moore, John W.; Moore, Elizabeth A.

    1988-01-01

    Surveys the types of computers being used in high school and university chemistry courses. Identifies types of hardware found on Apple and MS-DOS computers. Makes recommendations for the upgrading of current equipment. (ML)

  3. Microcomputer Decisions for the 1990s [and] Apple's Macintosh: A Viable Choice.

    ERIC Educational Resources Information Center

    Grosch, Audrey N.

    1989-01-01

    Discussion of the factors that should be considered when purchasing or upgrading a microcomputer focuses on the MS-DOS and OS/2 operating systems. Macintosh purchasing decisions are discussed in a sidebar. A glossary is provided. (CLB)

  4. Writing in Concert: A New Generation of Networked Software.

    ERIC Educational Resources Information Center

    Theisen, Emmy

    1992-01-01

    Describes "Let's Write!" a writing package for the MS-DOS network which combines five software programs to define a new collaborative dynamic for writing, reading, and thinking on computer networks. (SR)

  5. Parenting

    MedlinePlus

    ... parents, people are always ready to offer advice. Parenting tips, parents' survival guides, dos, don'ts, shoulds ... right" way to be a good parent. Good parenting includes Keeping your child safe Showing affection and ...

  6. Privileged structures: efficient chemical "navigators" toward unexplored biologically relevant chemical spaces.

    PubMed

    Kim, Jonghoon; Kim, Heejun; Park, Seung Bum

    2014-10-22

    In the search for new therapeutic agents for currently incurable diseases, attention has turned to traditionally "undruggable" targets, and collections of drug-like small molecules with high diversity and quality have become a prerequisite for new breakthroughs. To generate such collections, the diversity-oriented synthesis (DOS) strategy was developed, which aims to populate new chemical space with drug-like compounds containing a high degree of molecular diversity. The resulting DOS-derived libraries have been of great value for the discovery of various bioactive small molecules and therapeutic agents, and thus DOS has emerged as an essential tool in chemical biology and drug discovery. However, the key challenge has become how to design and synthesize drug-like small-molecule libraries with improved biological relevancy as well as maximum molecular diversity. This Perspective presents the development of privileged substructure-based DOS (pDOS), an efficient strategy for the construction of polyheterocyclic compound libraries with high biological relevancy. We envisioned the specific interaction of drug-like small molecules with certain biopolymers via the incorporation of privileged substructures into polyheterocyclic core skeletons. The importance of privileged substructures such as benzopyran, pyrimidine, and oxopiperazine in rigid skeletons was clearly demonstrated through the discovery of bioactive small molecules and the subsequent identification of appropriate target biomolecule using a method called "fluorescence difference in two-dimensional gel electrophoresis". Focusing on examples of pDOS-derived bioactive compounds with exceptional specificity, we discuss the capability of privileged structures to serve as chemical "navigators" toward biologically relevant chemical spaces. We also provide an outlook on chemical biology research and drug discovery using biologically relevant compound libraries constructed by pDOS, biology-oriented synthesis, or

  7. Simulium (Inaequalium) marins, a new species of black fly (Diptera: Simuliidae) from inselbergs in Brazil.

    PubMed

    Pepinelli, Mateus; Hamada, Neusa; Currie, Douglas C

    2009-08-01

    A new species of black fly, Simulium (Inaequalium) marins (Diptera: Simuliidae), is described based on the male, female, pupa and larva. This new species was collected from two localities: a small stream on the Pico dos Marins, a high mountain with granite outcrops in Piquete County, state of São Paulo, and in a small stream in the Serra dos Orgãos National Park, state of Rio de Janeiro, Brazil.

  8. Diversity-Oriented Synthesis as a Strategy for Fragment Evolution against GSK3β.

    PubMed

    Wang, Yikai; Wach, Jean-Yves; Sheehan, Patrick; Zhong, Cheng; Zhan, Chenyang; Harris, Richard; Almo, Steven C; Bishop, Joshua; Haggarty, Stephen J; Ramek, Alexander; Berry, Kayla N; O'Herin, Conor; Koehler, Angela N; Hung, Alvin W; Young, Damian W

    2016-09-01

    Traditional fragment-based drug discovery (FBDD) relies heavily on structural analysis of the hits bound to their targets. Herein, we present a complementary approach based on diversity-oriented synthesis (DOS). A DOS-based fragment collection was able to produce initial hit compounds against the target GSK3β, allow the systematic synthesis of related fragment analogues to explore fragment-level structure-activity relationship, and finally lead to the synthesis of a more potent compound. PMID:27660690

  9. Quantification of joint inflammation in rheumatoid arthritis by time-resolved diffuse optical spectroscopy and tracer kinetic modeling

    NASA Astrophysics Data System (ADS)

    Ioussoufovitch, Seva; Morrison, Laura B.; Lee, Ting-Yim; St. Lawrence, Keith; Diop, Mamadou

    2015-03-01

    Rheumatoid arthritis (RA) is characterized by chronic synovial inflammation, which can cause progressive joint damage and disability. Diffuse optical spectroscopy (DOS) and imaging have the potential to become potent monitoring tools for RA. We devised a method that combined time-resolved DOS and tracer kinetics modeling to rapidly and reliably quantify blood flow in the joint. Preliminary results obtained from two animals show that the technique can detect joint inflammation as early as 5 days after onset.

  10. 77 FR 24425 - Airworthiness Directives; Empresa Brasileria de Aeronáutica S.A. (EMBRAER) Airplanes

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-24

    ... Procedures (44 FR 11034, February 26, 1979), (3) Will not affect intrastate aviation in Alaska, and (4) Will.... Brigadeiro Faria Lima, 2170, S o Jos dos Campos--SP, CEP: 12227-901--P.O. Box 36/2, BRASIL; fax ++55 12 3927... dos Campos--SP, CEP: 12227-901--P.O. Box 36/2, BRASIL; fax ++55 12 3927- 2619; email...

  11. Low-threshold and high efficiency lasing upon band-edge excitation in a cholesteric liquid crystal

    NASA Astrophysics Data System (ADS)

    Matsuhisa, Yuko; Huang, Yuhua; Zhou, Ying; Wu, Shin-Tson; Ozaki, Ryotaro; Takao, Yuuki; Fujii, Akihiko; Ozaki, Masanori

    2007-02-01

    A low threshold and high efficiency laser based on dye-doped cholesteric liquid crystals (CLCs) is demonstrated using an input excitation with the same handedness of circular polarization as the helical structure of the sample at the shorter wavelength band edge of the reflection band. The responsible mechanism originates from the dramatic increase of the optical density of state (DOS) at the band edges. The calculated DOS of the CLC system confirms the authors' experimental results.

  12. Energy resolved electrochemical impedance spectroscopy for electronic structure mapping in organic semiconductors

    NASA Astrophysics Data System (ADS)

    Nádaždy, V.; Schauer, F.; Gmucová, K.

    2014-10-01

    We introduce an energy resolved electrochemical impedance spectroscopy method to map the electronic density of states (DOS) in organic semiconductor materials. The method consists in measurement of the charge transfer resistance of a semiconductor/electrolyte interface at a frequency where the redox reactions determine the real component of the impedance. The charge transfer resistance value provides direct information about the electronic DOS at the energy given by the electrochemical potential of the electrolyte, which can be adjusted using an external voltage. A simple theory for experimental data evaluation is proposed, along with an explanation of the corresponding experimental conditions. The method allows mapping over unprecedentedly wide energy and DOS ranges. Also, important DOS parameters can be determined directly from the raw experimental data without the lengthy analysis required in other techniques. The potential of the proposed method is illustrated by tracing weak bond defect states induced by ultraviolet treatment above the highest occupied molecular orbital in a prototypical σ-conjugated polymer, poly[methyl(phenyl)silylene]. The results agree well with those of our previous DOS reconstruction by post-transient space-charge-limited-current spectroscopy, which was, however, limited to a narrow energy range. In addition, good agreement of the DOS values measured on two common π-conjugated organic polymer semiconductors, polyphenylene vinylene and poly(3-hexylthiophene), with the rather rare previously published data demonstrate the accuracy of the proposed method.

  13. Mutational biosynthesis of neomycin analogs by a mutant of neomycin-producing Streptomyces fradiae.

    PubMed

    Shi, Guanying; Zhang, Xingang; Wu, Lang; Xie, Jin; Tao, Ke; Hou, Taiping

    2011-11-01

    Neomycin, produced by Streptomyces fradiae, has been widely used for the treatment of bacterial infections in clinical and agricultural applications. In this study, a neomycin nonproducing mutant of S. fradiae was obtained by gene disruption technique for mutational biosynthesis. A crucial gene neoC (neo7) which encodes 2-deoxystreptamine (2-DOS) synthases was disrupted. The mutant could resume producing neomycin in the presence of 2-DOS. Salen derivatives of 2-DOS were synthesized and individually added to cultures of the mutant. Antibacterial activity of the mutasynthesis products against Staphylococcus aureus and four plant pathogenic bacteria (Pseudomonas solanacarum, Erwinia carotovora, Xanthomonas oryzae, and Xanthomonas campestris) was detected quantitatively by Oxford cup method. It is suggested that all 2-DOS derivatives were incorporated by the mutant into new active neomycin analogs except for 2-DOS derivative 2d ((1R,2r,3S,4R,6S)-4,6-bis((E)-3,5-di-tert-butyl-2-hydroxybenzylideneamino)cyclohexane-1,2,3-triol). Neomycin analogs produced by feeding 2-DOS derivative 2a ((1R,2r,3S,4R,6S)-4,6-bis((E)-2 hydroxybenzylideneamino)cyclohexane-1,2,3-triol) to cultures of the mutant displayed a similar antibacterial activity with neomycin produced by wild strain.

  14. Energy resolved electrochemical impedance spectroscopy for electronic structure mapping in organic semiconductors

    SciTech Connect

    Nádaždy, V. Gmucová, K.; Schauer, F.

    2014-10-06

    We introduce an energy resolved electrochemical impedance spectroscopy method to map the electronic density of states (DOS) in organic semiconductor materials. The method consists in measurement of the charge transfer resistance of a semiconductor/electrolyte interface at a frequency where the redox reactions determine the real component of the impedance. The charge transfer resistance value provides direct information about the electronic DOS at the energy given by the electrochemical potential of the electrolyte, which can be adjusted using an external voltage. A simple theory for experimental data evaluation is proposed, along with an explanation of the corresponding experimental conditions. The method allows mapping over unprecedentedly wide energy and DOS ranges. Also, important DOS parameters can be determined directly from the raw experimental data without the lengthy analysis required in other techniques. The potential of the proposed method is illustrated by tracing weak bond defect states induced by ultraviolet treatment above the highest occupied molecular orbital in a prototypical σ-conjugated polymer, poly[methyl(phenyl)silylene]. The results agree well with those of our previous DOS reconstruction by post-transient space-charge-limited-current spectroscopy, which was, however, limited to a narrow energy range. In addition, good agreement of the DOS values measured on two common π-conjugated organic polymer semiconductors, polyphenylene vinylene and poly(3-hexylthiophene), with the rather rare previously published data demonstrate the accuracy of the proposed method.

  15. Modeling sediment resuspension-induced DO variation in fine-grained streams.

    PubMed

    Zahraeifard, Vahid; Deng, Zhiqiang

    2012-12-15

    Dissolved Oxygen (DO) levels in streams with nutrient enriched fine-grained sediment are highly affected by sediment resuspension. This paper presents a new model, called VART-DOS model, for simulation of instream DO transport, DO exchanges across water-sediment and water-air interfaces, and DO variation in response to sediment resuspension. The sediment resuspension effect is described by introducing a lumped term as a product of DO concentration and a rate of sediment resuspension-induced DO consumption (Λ). The rate parameter Λ is defined as a nonlinear function of average summer temperature of water and several sediment erosion-related parameters. This is a novel and unique feature of the VART-DOS model. Based on sensitivity analysis, effects of BOD and Sediment Oxygen Demand (SOD) on DO consumption are not so important as compared to sediment resuspension which can cause up to 83% reduction in DO level during high flow. The VART-DOS model was applied to the Lower Amite River in Louisiana, USA to perform continuous simulations of DO fluctuations in the winter month January and the summer month July involving several flood-induced sediment resuspension events. Simulation results indicate that the VART-DOS model is capable of capturing overall variation trends in DO concentration. The Normalized Root Mean Square Error (RMSE) between VART-DOS simulated and observed DO levels was 0. 42 for January and 0.23 for July, demonstrating the efficacy of the VART-DOS model. PMID:23137983

  16. Density of quantum states in quasi-1D layers

    NASA Astrophysics Data System (ADS)

    Kakulia, D.; Tavkhelidze, A.; Gogoberidze, V.; Mebonia, M.

    2016-04-01

    Recently, new quantum effects have been studied in thin nanograting layers. Nanograting on the surface imposes additional boundary conditions on the electron wave function and reduces the density of states (DOS). When the nanograting dimensions are close to the de Broglie wavelength, the DOS reduction is considerable and leads to changes in the layer properties. DOS calculations are challenging to perform and are related to the quantum billiard problem. Performing such calculations requires finding the solutions for the time-independent Schrödinger equation with Dirichlet boundary conditions. Here, we use a numerical method, namely the Method of Auxiliary Sources, which offers significant computational cost reduction relative to other numerical methods. We found the first five eigenfunctions for the nanograting layer and compared them with the corresponding eigenfunctions for a plain layer by calculating the correlation coefficients. Furthermore, the numerical data were used to analyze the DOS reduction. The nanograting is shown to reduce the probability of occupation of a particular quantum state, reducing the integrated DOS by as much as 4.1-fold. This reduction in the DOS leads to considerable changes in the electronic properties.

  17. [Biomarkers of cervical carcinogenesis associated with genital human papillomavirus infection].

    PubMed

    Oliveira, Ana; Delgado, Candida; Verdasca, Nuno; Pista, Angela

    2013-01-01

    Introdução/Objetivos: A infeção persistente pelo Vírus do Papiloma Humano de alto risco (HPVar) é considerada como a causa necessária, embora não suficiente, para o desenvolvimento do cancro do colo do útero, sugerindo que outros fatores estarão envolvidos no processo de carcinogénese. Este estudo pretendeu avaliar indicadores de prognóstico da persistência da infeção por HPV, nomeadamente o estado físico e a carga viral dos HPV 16 e 18 e a superexpressão dos transcritos do RNAm dos HPV 16, 18, 31, 33 e 45, num grupo de mulheres com ou sem sintomatologia clínica e citopatológica. Material e Métodos: Foram estudadas 378 alíquotas de células epiteliais congeladas pertencentes a utentes dos centros de saúde do Serviço Nacional de Saúde e de clínicas privadas, referenciadas para teste HPV, entre Janeiro de 2007 e Dezembro de 2010. De acordo com o diagnóstico citopatológico, foram definidos cinco grupos: normal, ASCUS, LSIL, HSIL e carcinoma invasivo do colo do útero. Para a determinação do estado físico do DNA e da carga viral dos HPV 16 e 18 foi utilizada metodologia de PCR em tempo real, e para a superexpressão dos transcritos dos oncogenes E6 e E7 o sistema comercial NucliSENS EasyQ HPV®. Os indicadores foram analisados em associação com os tipos de lesão do colo do útero. Para a análise estatística foi utilizado o o programa informático SPSS versão 16.0 e o teste de Chi-Quadrado. Resultados: Os resultados mostraram ausência de associação estatisticamente significativa entre a gravidade da lesão e o estado físico do DNA dos HPV 16 e 18. A superexpressão dos transcritos do RNAm E6/E7 e a carga viral dos HPV 16 e 18 aumentaram significativamente em função do grau da lesão. Conclusões: Os resultados obtidos sugerem que a determinação do estado físico do DNA dos HPV 16 e 18, isoladamente, não constitui um indicador de prognóstico para o desenvolvimento e progressão das lesões. A superexpressão dos transcritos

  18. Effects of cumulus cells on rabbit oocyte in vitro maturation.

    PubMed

    Tao, Y; Cao, C; Zhang, M; Fang, F; Liu, Y; Zhang, Y; Ding, J; Zhang, X

    2008-08-01

    Cumulus cells (CCs) are of great importance in oocyte development and maturation in many species, but detailed influence of CCs has not been extensively examined, especially on rabbit. The present study was designed to investigate the effects of CCs and the elongation of in vitro maturation (IVM) time on rabbit oocyte nuclear and ooplasmic maturation and survival. Cumulus oocyte complexes (COCs) and naked oocytes (NOs) were recovered directly from rabbits super-ovulated with eCG. Corona-enclosed oocytes (COs) and denuded oocytes (DOs) were obtained from COCs after removing a part or whole of CCs. The oocytes were cultured in the following seven groups. (i) Cumulus cell enclosed oocytes (CEOs) were cultured alone (CEOs); (ii) COs were cultured alone (COs); (iii) DOs were cultured alone (DOs); (iv) NOs were cultured alone; (v) DOs were co-cultured with COCs [DOs(COCs)]; (vi) DOs were co-cultured with CCs [DOs(CCs)]; (vii) NOs were co-cultured with CCs [NOs(CCs)]. After the oocytes were cultured for 24 and 30 h, the nuclear maturation was evaluated by first polar body (PB1) extrusion while the ooplasmic maturation was evaluated by the cleavage rate after parthenogenetic activation. The results showed that the nuclear maturation rate of CEOs, COs, DOs(COCs) and DOs(CCs) after 24 h incubation were significantly different from each other (p < or = 0.05), the rate of DOs(CCs) was similar to that of DOs (p > or = 0.05). The cleavage rates in the first two groups were significantly higher than those of the others (p < 0.05). For oocytes cultured for 30 h, the nuclear maturation rates were significantly different for each culture model (p < 0.05). The cleavage rates in first two groups were significantly higher than those of others (p < 0.05). Both the nuclear and cleavage rates significantly increased when the culture time of DOs(COCs) was prolonged from 24 to 30 h. DOs(CCs) nuclear maturation was significantly improved when the culture time was prolonged from 24 to 30 h

  19. Phonon density of states of Sn in textured SnO under high pressure: Comparison of nuclear inelastic x-ray scattering spectra to a shell model

    SciTech Connect

    Giefers, H.; Koval, S.; Wortmann, G.; Sturhahn, W.; Alp, E. E.; Hu, M. Y.

    2006-09-01

    The local phonon density of states (DOS) at the Sn site in tin monoxide (SnO) is studied at pressures up to 8 GPa with {sup 119}Sn nuclear resonant inelastic x-ray scattering (NRIXS) of synchrotron radiation at 23.88 keV. The preferred orientation (texture) of the SnO crystallites in the investigated samples is used to measure NRIXS spectra preferentially parallel and almost perpendicular to the c axis of tetragonal SnO. A subtraction method is applied to these NRIXS spectra to produce projected local Sn DOS spectra as seen parallel and perpendicular to the c axis of SnO. These experimentally obtained local Sn DOS spectra, both in the polycrystalline case as well as projected parallel and perpendicular to the c axis, are compared with corresponding theoretical phonon DOS spectra, derived from dispersion relations calculated with a recently developed shell model. Comparison between the experimental projected Sn DOS spectra and the corresponding theoretical DOS spectra enables us to follow the pressure-induced shifts of several acoustic and optic phonon modes. While the principal spectral features of the experimental and theoretical phonon DOS agree well at energies above 10 meV, the pressure behavior of the low-energy part of the DOS is not well reproduced by the theoretical calculations. In fact, they exhibit, in contrast to the experimental data, a dramatic softening of two low-energy modes, their energies approaching zero around 2.5 GPa, clearly indicating the limitations of the applied shell model. These difficulties are obviously connected with the complex Sn-O and Sn-Sn bindings within and between the Sn-O-Sn layers in the litharge structure of SnO. We derived from the experimental and theoretical DOS spectra a variety of elastic and thermodynamic parameters of the Sn sublattice, such as the Lamb-Moessbauer factor, the mean force constant, and Debye temperatures, as well as the vibrational contributions to the Helmholtz free energy, specific heat, entropy, and

  20. Molecular evidence for abiotic sulfurization of dissolved organic matter in marine shallow hydrothermal systems

    NASA Astrophysics Data System (ADS)

    Gomez-Saez, Gonzalo V.; Niggemann, Jutta; Dittmar, Thorsten; Pohlabeln, Anika M.; Lang, Susan Q.; Noowong, Ann; Pichler, Thomas; Wörmer, Lars; Bühring, Solveig I.

    2016-10-01

    Shallow submarine hydrothermal systems are extreme environments with strong redox gradients at the interface of hot, reduced fluids and cold, oxygenated seawater. Hydrothermal fluids are often depleted in sulfate when compared to surrounding seawater and can contain high concentrations of hydrogen sulfide (H2S). It is well known that sulfur in its various oxidation states plays an important role in processing and transformation of organic matter. However, the formation and the reactivity of dissolved organic sulfur (DOS) in the water column at hydrothermal systems are so far not well understood. We investigated DOS dynamics and its relation to the physicochemical environment by studying the molecular composition of dissolved organic matter (DOM) in three contrasting shallow hydrothermal systems off Milos (Eastern Mediterranean), Dominica (Caribbean Sea) and Iceland (North Atlantic). We used ultra-high resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) to characterize the DOM on a molecular level. The molecular information was complemented with general geochemical data, quantitative dissolved organic carbon (DOC) and DOS analyses as well as isotopic measurements (δ2H, δ18O and F14C). In contrast to the predominantly meteoric fluids from Dominica and Iceland, hydrothermal fluids from Milos were mainly fed by recirculating seawater. The hydrothermal fluids from Milos were enriched in H2S and DOS, as indicated by high DOS/DOC ratios and by the fact that >90% of all assigned DOM formulas that were exclusively present in the fluids contained sulfur. In all three systems, DOS from hydrothermal fluids had on average lower O/C ratios (0.26-0.34) than surrounding surface seawater DOS (0.45-0.52), suggesting shallow hydrothermal systems as a source of reduced DOS, which will likely get oxidized upon contact with oxygenated seawater. Evaluation of hypothetical sulfurization reactions suggests DOM reduction and sulfurization during seawater

  1. Structures of the catalytic EAL domain of the Escherichia coli direct oxygen sensor.

    PubMed

    Tarnawski, Miroslaw; Barends, Thomas R M; Hartmann, Elisabeth; Schlichting, Ilme

    2013-06-01

    The direct oxygen sensor DosP is a multidomain protein that contains a gas-sensing haem domain and an EAL effector domain. EAL domains are omnipresent signal transduction domains in bacteria. Many EAL domains are active phosphodiesterases and are involved in breakdown of the ubiquitous bacterial second messenger cyclic di-GMP. Despite a great deal of information on the functional and structural aspects of active and inactive EAL domains, little is known about the structural basis of their regulation by their associated sensory domains. Here, two crystal structures of the Escherichia coli DosP EAL domain derived from cubic and monoclinic crystal forms that were obtained under tartrate and PEG conditions, respectively, are described. Both of the structures display the typical TIM (triosephosphate isomerase) barrel fold with one antiparallel β-strand. However, unlike other EAL structures, access to the active site in DosP EAL is sterically restricted by the presence of a short helical stretch (Ser637-Ala-Leu-His640) in loop L3 between strand β3 and helix α3. This element, together with an unordered fragment, replaces the short α-helix (named α5 in Tbd1265 EAL) that is found in other EAL-domain structures. Since DosP EAL is an active c-di-GMP phosphodiesterase, the observed inactive conformation is suggested to be of functional relevance for the regulation mechanism of DosP.

  2. Oocyte-secreted factors in oocyte maturation media enhance subsequent development of bovine cloned embryos.

    PubMed

    Su, Jianmin; Wang, Yongsheng; Zhang, Lei; Wang, Bo; Liu, Jun; Luo, Yan; Guo, Zekun; Quan, Fusheng; Zhang, Yong

    2014-04-01

    Successful in vitro maturation (IVM) and oocyte quality both affect the subsequent development of cloned embryos derived from somatic-cell nuclear transfer (SCNT). Developmental competence is usually lower in oocytes matured in vitro compared with those that matured in vivo, possibly due to insufficient levels of oocyte-secreted factors (OSFs) and disrupted oocyte-cumulus communication. This study investigated the effects of OSFs secreted by denuded oocytes (DOs) during IVM on the subsequent developmental competence of cloned bovine embryos. Cumulus-oocyte complexes (COCs) from antral follicles of slaughtered-cow ovaries collected from an abattoir were divided into four groups: COCs co-cultured with and without DOs in maturation media used for SCNT, as well as COCs co-cultured with and without DOs in maturation media used for in vitro fertilization (IVF). Based on the developmental competence and embryo quality of bovine embryos generated from these four groups, we found that co-culturing the COCs with DOs enhanced the in vitro development of IVF and cloned bovine embryos, and potentially generated more high-quality cloned blastocysts that possessed locus-specific histone modifications at levels similar to in vitro-fertilized embryos. These results strongly suggest that co-culturing COCs with DOs enhances subsequent developmental competence of cloned bovine embryo.

  3. Superconductivity in Bismuth. A New Look at an Old Problem.

    PubMed

    Mata-Pinzón, Zaahel; Valladares, Ariel A; Valladares, Renela M; Valladares, Alexander

    2016-01-01

    To investigate the relationship between atomic topology, vibrational and electronic properties and superconductivity of bismuth, a 216-atom amorphous structure (a-Bi216) was computer-generated using our undermelt-quench approach. Its pair distribution function compares well with experiment. The calculated electronic and vibrational densities of states (eDOS and vDOS, respectively) show that the amorphous eDOS is about 4 times the crystalline at the Fermi energy, whereas for the vDOS the energy range of the amorphous is roughly the same as the crystalline but the shapes are quite different. A simple BCS estimate of the possible crystalline superconducting transition temperature gives an upper limit of 1.3 mK. The e-ph coupling is more preponderant in a-Bi than in crystalline bismuth (x-Bi) as indicated by the λ obtained via McMillan's formula, λc = 0.24 and experiment λa = 2.46. Therefore with respect to x-Bi, superconductivity in a-Bi is enhanced by the higher values of λ and of eDOS at the Fermi energy.

  4. Low-energy density of states in d-wave superconductors with extended scatterers

    NASA Astrophysics Data System (ADS)

    Adagideli, I.; Sheehy, D. E.; Goldbart, P. M.

    2002-03-01

    We investigate a novel contribution to the low-energy quasiparticle density of states (DOS) of a disordered d-wave superconductor. Related work (C. Pépin and P. A. Lee, Phys. Rev. B 63), 054502 (2001). found that the DOS is singular at zero energy, but it was later argued (A.G. Yashenkin et al., Phys. Rev. Lett. 86), 5982 (2001); A. Altland, cond-mat/0108079 (unpublished). that the results of Ref. [1] are valid only in special cases requiring fine-tuning of the parameters, and that the DOS vanishes at E=0 except in these cases. A common feature of these approaches is the assumption that the disorder potential is due to pointlike scatterers. However, previous work (I. Adagideli et al., Phys. Rev. Lett. 83) 5571 (1999). showed that the presence of extended impurities in d-wave superconductors gives rise to additional low-energy quasiparticle states. Motivated by this fact, we focus on the (previously neglected) contribution to the low-energy DOS arising from a disorder potential that consists of a random collection of extended impurities. We find that the DOS is singular at zero energy, diverging as ρ_ext(E) ~ 1/\\vert E(ln \\vert E\\vert)^3 \\vert. Our calculation neglects the role of nodal quasiparticles; indeed, we expect that they will merely furnish a subdominant additive contribution to ρ_ ext. This work was supported by D.O.E.

  5. Investigation into the Gaussian density of states widths of organic semiconductors

    NASA Astrophysics Data System (ADS)

    Whitcher, T. J.; Wong, W. S.; Talik, A. N.; Woon, K. L.; Chanlek, N.; Nakajima, H.; Saisopa, T.; Songsiriritthigul, P.

    2016-08-01

    The determination of the Gaussian density of states (DOS) width and its influence on charge injection/extraction across an interface are of critical importance for the accurate physical understanding of the optoelectronic properties of organic electronics. A new technique is developed here, whereby the DOS width is extracted by numerical fitting of experimental band-bending observed across an interface. This is done by exploiting the fact that the band-bending can be influenced by the disordered nature of energetic sites that are involved in charge transfer across an interface. This technique is applied on a single component and blended mixture of materials. This approach is successfully tested on poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), poly(N-vinylcarbazole) (PVK), 2,7-bis(diphenylphosphoryl)-9,9‧-spirobifluorene (SPPO13) and poly(3-hexylthiophene-2,5-diyl) (P3HT) in a number of interfaces. The DOS width of PEDOT:PSS, PVK, SPPO13 and P3HT were calculated to be 105 meV, 144 meV, 178 meV and 80 meV respectively. The impact of DOS width on the interface between two materials is investigated. The Fermi level pinning model used to describe the hole barrier between an inorganic electrode and an organic semiconductor fails when applied to the interface between two organic semiconductors. Their energetic barriers are very highly dependent on the DOS of the materials.

  6. Influence of co-culture with denuded oocytes during in vitro maturation on fertilization and developmental competence of cumulus-enclosed porcine oocytes in a defined system.

    PubMed

    Appeltant, Ruth; Somfai, Tamás; Kikuchi, Kazuhiro; Maes, Dominiek; Van Soom, Ann

    2016-04-01

    Co-culture of cumulus-oocyte complexes (COCs) with denuded oocytes (DOs) during in vitro maturation (IVM) was reported to improve the developmental competence of oocytes via oocyte-secreted factors in cattle. The aim of the present study was to investigate if addition of DOs during IVM can improve in vitro fertilization (IVF) and in vitro culture (IVC) results for oocytes in a defined in vitro production system in pigs. The maturation medium was porcine oocyte medium supplemented with gonadotropins, dbcAMP and β-mercaptoethanol. Cumulus-oocyte complexes were matured without DOs or with DOs in different ratios (9 COC, 9 COC+16 DO and 9 COC+36 DO). Consequently; oocytes were subjected to IVF as intact COCs or after denudation to examine if DO addition during IVM would affect cumulus or oocyte properties. After fertilization, penetration and normal fertilization rates of zygotes were not different between all tested groups irrespective of denudation before IVF. When zygotes were cultured for 6 days, no difference could be observed between all treatment groups in cleavage rate, blastocyst rate and cell number per blastocyst. In conclusion, irrespective of the ratio, co-culture with DOs during IVM did not improve fertilization parameters and embryo development of cumulus-enclosed porcine oocytes in a defined system.

  7. Superconductivity in Bismuth. A New Look at an Old Problem.

    PubMed

    Mata-Pinzón, Zaahel; Valladares, Ariel A; Valladares, Renela M; Valladares, Alexander

    2016-01-01

    To investigate the relationship between atomic topology, vibrational and electronic properties and superconductivity of bismuth, a 216-atom amorphous structure (a-Bi216) was computer-generated using our undermelt-quench approach. Its pair distribution function compares well with experiment. The calculated electronic and vibrational densities of states (eDOS and vDOS, respectively) show that the amorphous eDOS is about 4 times the crystalline at the Fermi energy, whereas for the vDOS the energy range of the amorphous is roughly the same as the crystalline but the shapes are quite different. A simple BCS estimate of the possible crystalline superconducting transition temperature gives an upper limit of 1.3 mK. The e-ph coupling is more preponderant in a-Bi than in crystalline bismuth (x-Bi) as indicated by the λ obtained via McMillan's formula, λc = 0.24 and experiment λa = 2.46. Therefore with respect to x-Bi, superconductivity in a-Bi is enhanced by the higher values of λ and of eDOS at the Fermi energy. PMID:26815431

  8. The impact of interhospital transfers on surgical quality metrics for academic medical centers.

    PubMed

    Crippen, Cristina J; Hughes, Steven J; Chen, Sugong; Behrns, Kevin E

    2014-07-01

    The emergence of pay-for-performance systems pose a risk to an academic medical center's (AMC) mission to provide care for interhospital surgical transfer patients. This study examines quality metrics and resource consumption for a sample of these patients from the University Health System Consortium (UHC) and our Department of Surgery (DOS). Standard benchmarks, including mortality rate, length of stay (LOS), and cost, were used to evaluate the impact of interhospital surgical transfers versus direct admission (DA) patients from January 2010 to December 2012. For 1,423,893 patients, the case mix index for transfer patients was 38 per cent (UHC) and 21 per cent (DOS) greater than DA patients. Mortality rates were 5.70 per cent (UHC) and 6.93 per cent (DOS) in transferred patients compared with 1.79 per cent (UHC) and 2.93 per cent (DOS) for DA patients. Mean LOS for DA patients was 4 days shorter. Mean total costs for transferred patients were greater $13,613 (UHC) and $13,356 (DOS). Transfer patients have poorer outcomes and consume more resources than DA patients. Early recognition and transfer of complex surgical patients may improve patient rescue and decrease resource consumption. Surgeons at AMCs and in the community should develop collaborative programs that permit collective assessment and decision-making for complicated surgical patients.

  9. The impact of interhospital transfers on surgical quality metrics for academic medical centers.

    PubMed

    Crippen, Cristina J; Hughes, Steven J; Chen, Sugong; Behrns, Kevin E

    2014-07-01

    The emergence of pay-for-performance systems pose a risk to an academic medical center's (AMC) mission to provide care for interhospital surgical transfer patients. This study examines quality metrics and resource consumption for a sample of these patients from the University Health System Consortium (UHC) and our Department of Surgery (DOS). Standard benchmarks, including mortality rate, length of stay (LOS), and cost, were used to evaluate the impact of interhospital surgical transfers versus direct admission (DA) patients from January 2010 to December 2012. For 1,423,893 patients, the case mix index for transfer patients was 38 per cent (UHC) and 21 per cent (DOS) greater than DA patients. Mortality rates were 5.70 per cent (UHC) and 6.93 per cent (DOS) in transferred patients compared with 1.79 per cent (UHC) and 2.93 per cent (DOS) for DA patients. Mean LOS for DA patients was 4 days shorter. Mean total costs for transferred patients were greater $13,613 (UHC) and $13,356 (DOS). Transfer patients have poorer outcomes and consume more resources than DA patients. Early recognition and transfer of complex surgical patients may improve patient rescue and decrease resource consumption. Surgeons at AMCs and in the community should develop collaborative programs that permit collective assessment and decision-making for complicated surgical patients. PMID:24987902

  10. Psychiatry training towards a global future: trainees' perspective in Portugal.

    PubMed

    Pinto da Costa, Mariana; Guerra, Cátia; Malta, Rui; Moura, Manuela; Carvalho, Serafim; Mendonça, Denisa

    2013-01-01

    Introdução: A psiquiatria é influenciada pelas mudanças que ocorrem na sociedade, devendo estar em constante renovação, antevendo futuros comportamentos e doenças. Este estudo pretende descrever a opinião dos internos de psiquiatria em Portugal relativamente ao seu internato e às modificações que nele gostariam de assistir no futuro próximo.Material e Métodos: Um questionário estruturado de 26 perguntas foi desenvolvido pela Associação Portuguesa de Internos de Psiquiatria e enviado por email.Resultados: A percentagem de respostas obtidas foi de 41,5%. A maioria dos internos estava satisfeita com a sua formação. Contudo, algumas mudanças foram sugeridas no que diz respeitos aos estágios obrigatórios e opcionais. A maior parte dos internos requer que as psicoterapias sejam incluídas no âmbito do internato, solicitando também um acesso mais fácil à investigação e a oportunidades de estágio no estrangeiro.Discussão e Conclusão: Esta perspectiva detalhada pode facilitar a transformação dos currículos do internato em Portugal e naEuropa, permitindo a melhoria do internato de psiquiatria, bem como dos cuidados de saúde mental.

  11. Superconductivity in Bismuth. A New Look at an Old Problem

    PubMed Central

    2016-01-01

    To investigate the relationship between atomic topology, vibrational and electronic properties and superconductivity of bismuth, a 216-atom amorphous structure (a-Bi216) was computer-generated using our undermelt-quench approach. Its pair distribution function compares well with experiment. The calculated electronic and vibrational densities of states (eDOS and vDOS, respectively) show that the amorphous eDOS is about 4 times the crystalline at the Fermi energy, whereas for the vDOS the energy range of the amorphous is roughly the same as the crystalline but the shapes are quite different. A simple BCS estimate of the possible crystalline superconducting transition temperature gives an upper limit of 1.3 mK. The e-ph coupling is more preponderant in a-Bi than in crystalline bismuth (x-Bi) as indicated by the λ obtained via McMillan’s formula, λc = 0.24 and experiment λa = 2.46. Therefore with respect to x-Bi, superconductivity in a-Bi is enhanced by the higher values of λ and of eDOS at the Fermi energy. PMID:26815431

  12. Influence of annealing atmospheres and synthetic air treatment on solution processed zinc oxide thin film transistors

    NASA Astrophysics Data System (ADS)

    Busch, C.; Schierning, G.; Theissmann, R.; Schmechel, R.

    2012-08-01

    Thin film transistors (TFTs) based on active layers of zinc oxide prepared from a solution process were fabricated under different annealing conditions. The influence of the annealing gas as well as the influence of a subsequent exposure to synthetic air to the device properties is considered. Annealing under N2 or H2 atmosphere leads to a strong negative threshold voltage shift. With respect to known defect states in ZnO, two different donor states are suggested to be responsible for the negative threshold voltage. A subsequent synthetic air treatment causes in general a positive threshold voltage shift. However, transistors annealed under H2 degrade very fast under synthetic air in contrast to transistors annealed under N2. In order to obtain more information about the density of states (DOS) distribution, a transistor model for thin film transistors in the hopping transport regime (Vissenberg model) was utilized. For positive threshold voltages, the DOS distribution is independent from the gas treatment and the threshold voltage within the experimental accuracy. This indicates a shift of the Fermi-level within an exponentially decaying DOS. The change in the charge carrier density is either due to shallow donors or due to a charge transfer with acceptors at the surface. In contrast, for negative threshold voltages, the DOS distribution parameter rises, indicating a flatter DOS distribution. We suggest that the difference is due to the change from accumulation mode to the depletion mode of the device.

  13. Trap density of states in n-channel organic transistors: variable temperature characteristics and band transport

    SciTech Connect

    Cho, Joung-min Akiyama, Yuto; Kakinuma, Tomoyuki; Mori, Takehiko

    2013-10-15

    We have investigated trap density of states (trap DOS) in n-channel organic field-effect transistors based on N,N ’-bis(cyclohexyl)naphthalene diimide (Cy-NDI) and dimethyldicyanoquinonediimine (DMDCNQI). A new method is proposed to extract trap DOS from the Arrhenius plot of the temperature-dependent transconductance. Double exponential trap DOS are observed, in which Cy-NDI has considerable deep states, by contrast, DMDCNQI has substantial tail states. In addition, numerical simulation of the transistor characteristics has been conducted by assuming an exponential trap distribution and the interface approximation. Temperature dependence of transfer characteristics are well reproduced only using several parameters, and the trap DOS obtained from the simulated characteristics are in good agreement with the assumed trap DOS, indicating that our analysis is self-consistent. Although the experimentally obtained Meyer-Neldel temperature is related to the trap distribution width, the simulation satisfies the Meyer-Neldel rule only very phenomenologically. The simulation also reveals that the subthreshold swing is not always a good indicator of the total trap amount, because it also largely depends on the trap distribution width. Finally, band transport is explored from the simulation having a small number of traps. A crossing point of the transfer curves and negative activation energy above a certain gate voltage are observed in the simulated characteristics, where the critical V{sub G} above which band transport is realized is determined by the sum of the trapped and free charge states below the conduction band edge.

  14. Intraoperative optical assessment of photodynamic therapy response of superficial oral squamous cell carcinoma

    NASA Astrophysics Data System (ADS)

    Rohrbach, Daniel J.; Rigual, Nestor; Arshad, Hassan; Tracy, Erin C.; Cooper, Michelle T.; Shafirstein, Gal; Wilding, Gregory; Merzianu, Mihai; Baumann, Heinz; Henderson, Barbara W.; Sunar, Ulas

    2016-01-01

    This study investigated whether diffuse optical spectroscopy (DOS) measurements could assess clinical response to photodynamic therapy (PDT) in patients with head and neck squamous cell carcinoma (HNSCC). In addition, the correlation between parameters measured with DOS and the crosslinking of signal transducer and activator of transcription 3 (STAT3), a molecular marker for PDT-induced photoreaction, was investigated. Thirteen patients with early stage HNSCC received the photosensitizer 2-[1-hexyloxyethyl]-2-devinylpyropheophorbide-a (HPPH) and DOS measurements were performed before and after PDT in the operating room (OR). In addition, biopsies were acquired after PDT to assess the STAT3 crosslinking. Parameters measured with DOS, including blood volume fraction, blood oxygen saturation (StO2), HPPH concentration (cHPPH), HPPH fluorescence, and blood flow index (BFI), were compared to the pathologic response and the STAT3 crosslinking. The best individual predictor of pathological response was a change in cHPPH (sensitivity=60%, specificity=100%), while discrimination analysis using a two-parameter classifier (change in cHPPH and change in StO2) classified pathological response with 100% sensitivity and 100% specificity. BFI showed the best correlation with the crosslinking of STAT3. These results indicate that DOS-derived parameters can assess the clinical response in the OR, allowing for earlier reintervention if needed.

  15. Carbon Nanotubes with Tailored Density of Electronic States for Electrochemical Applications.

    PubMed

    Song, Yingpan; Hu, Huifang; Feng, Miao; Zhan, Hongbing

    2015-11-25

    The density of electronic states (DOS) is an intrinsic electronic property that works conclusively in the electrochemistry of carbon materials. However, seldom has it been reported how the DOS at the Fermi level influences the electrochemical activity. In this work, we synthesized partially and fully unzipped carbon nanotubes by longitudinally unzipping pristine carbon nanotubes (CNTs). We then studied the electrochemical activity and biosensitivity of carbon materials by means of the CNTs and their derivatives to elucidate the effect of the DOS on their electrochemical performances. Tailoring of the DOS for the CNT derivatives could be conveniently realized by varying the sp(2)/sp(3) ratio (i.e., graphite concentration) through manipulating the oxidative unzipping degree. Despite the diverse electron transfer mechanisms and influence factors of the four investigated redox probes (IrCl6(2-), [Fe(CN)6](3-), Fe(3+), and ascorbic acid), the CNT derivatives exhibited consistent kinetic behaviors, wherein CNTs with a high DOS showed superior electrochemical response compared with partially and fully unzipped carbon nanotubes. For biological detection, the CNTs could simultaneously distinguish ascorbic acid, dopamine, and uric acid, while the three CNT derivatives could all differentiate phenethylamine and epinephrine existed in the newborn calf serum. Moreover, the three CNT derivatives all presented wide linear detection ranges with high sensitivities for dopamine, phenethylamine, and epinephrine.

  16. Death obsession in Palestinians.

    PubMed

    Abdel-Khalek, Ahmed M; Al-Arja, Nahida S; Abdalla, Taysir

    2006-04-01

    The authors explored death obsession level and correlates among a sample (N = 601) of Palestinians living in the city of Beit Jala, the village of Al-Khader, and the Aida refugee camp in the Bethlehem area. They live in war conditions; the houses of half of them have been demolished. The Death Obsession Scale (DOS) was administered. Its alpha reliability was .92, denoting high internal consistency. Among women, it yielded 1 factor, (General Death Obsession), whereas among men it yielded 3 factors: Death Rumination, Death Dominance, and Death Idea Repetition. Palestinian men and women attained significantly lower DOS mean scores than participants from 4 Arab countries: Egypt, Kuwait, Syria, and Lebanon in 7 out of 8 comparisons. However, Palestinian women had significantly higher DOS mean score than their Spanish, American and British counterparts, whereas Palestinian men had significantly higher mean DOS score than Spanish peers. The low DOS scores of Palestinians, in proportion to other Arab samples, may reflect their adaptation to strife and violence.

  17. In vivo water state measurements in breast cancer using broadband diffuse optical spectroscopy

    NASA Astrophysics Data System (ADS)

    Chung, S. H.; Cerussi, A. E.; Klifa, C.; Baek, H. M.; Birgul, O.; Gulsen, G.; Merritt, S. I.; Hsiang, D.; Tromberg, B. J.

    2008-12-01

    Structural changes in water molecules are related to physiological, anatomical and pathological properties of tissues. Near infrared (NIR) optical absorption methods are sensitive to water; however, detailed characterization of water in thick tissues is difficult to achieve because subtle spectral shifts can be obscured by multiple light scattering. In the NIR, a water absorption peak is observed around 975 nm. The precise NIR peak's shape and position are highly sensitive to water molecular disposition. We introduce a bound water index (BWI) that quantifies shifts observed in tissue water absorption spectra measured by broadband diffuse optical spectroscopy (DOS). DOS quantitatively measures light absorption and scattering spectra and therefore reveals bound water spectral shifts. BWI as a water state index was validated by comparing broadband DOS to magnetic resonance spectroscopy, diffusion-weighted MRI and conductivity in bound water tissue phantoms. Non-invasive DOS measurements of malignant and normal breast tissues performed in 18 subjects showed a significantly higher fraction of free water in malignant tissues (p < 0.0001) compared to normal tissues. BWI of breast cancer tissues inversely correlated with Nottingham-Bloom-Richardson histopathology scores. These results highlight broadband DOS sensitivity to molecular disposition of water and demonstrate the potential of BWI as a non-invasive in vivo index that correlates with tissue pathology.

  18. Study of the electronic and magnetic properties of EuAlO{sub 3} using FP-LAPW method

    SciTech Connect

    Sandeep, Shankar, A.; Rai, D. P.; Thapa, R. K.; Ghimire, M. P.

    2015-05-15

    The electronic and magnetic properties of EuAlO{sub 3} is calculated by first-principles full-potential linearized augmented plane wave (FP-LAPW) method based on density functional theory (DFT). Density of states (DOS), magnetic moments and band structures of the systems are presented. For the exchange and correlation energy, local spin density approximation (LSDA+U) with the inclusion of Hubbard potential U is used. Our calculation showed an indirect band gap of the order of 4 eV for EuAlO{sub 3} in the spin down channel of the DOS and band structures supporting HMF nature of the system. The effective magnetic moment of 6.00 µ{sub B} also supported the above conclusion with an integral value. The DOS of Eu were found responsible for the HMF nature of the system.

  19. Buracos negros primordiais e astrofísica observacional

    NASA Astrophysics Data System (ADS)

    Custódio, P. S.; Horvath, J. E.

    2003-02-01

    A história da física contemporânea é pródiga em grandes descobertas (a Relatividade e a Mecânica Quântica entre as mais importantes) até meados dos anos '30. O peso destes desenvolvimentos é tão grande que outros feitos de grande porte (por exemplo, a teoria da nucleossíntese nas estrelas) são geralmente considerados como "filhotes" dos primeiros, ao menos na imaginação popular. Porém, algumas exceções à regra não-escrita são dignas de menção. Entre estas últimas está a descoberta por S.W.Hawking e colaboradores das propriedades de emissão dos buracos negros, trabalho que iniciou uma disciplina com vida própria denominada Termodinâmica de Buracos Negros.

  20. Resonance frequency shifts due to quantized electronic states in atomically thin NEMS

    NASA Astrophysics Data System (ADS)

    Chen, Changyao; Deshpande, Vikram; Koshino, Mikito; Lee, Sunwoo; Gondarenko, Alexander; MacDonald, Allan; Kim, Philip; Hone, James

    The classic picture of the force exerted on a parallel plate capacitor assumes infinite density of states (DOS), which implies identical electrochemical and electrostatic potential. However, such assumption can breakdown in low-dimensional devices where the DOS is finite or quantized. Here we consider the mechanical resonance shift of a nanoelectromechanical (NEMS) resonator with small DOS, actuated and detected capacitively at fixed electrochemical potential. We found three leading correction terms to the classical picture: the first term leads to the modulation of static force due to the variation in chemical potential, and the second and third terms are related to the static and dynamic changes in spring constants, caused by quantum capacitance. The theory agrees well with recent experimental findings from graphene resonator in quantum Hall regimes, where the chemical potential and quantum capacitance are tuned by magnetic field, while the gate voltage is kept constant.