Patients with stable chronic obstructive pulmonary disease can safely undergo intravenous dipyridamole thallium-201 imaging.

PubMed

Shaffer, J; Simbartl, L; Render, M L; Snow, E; Chaney, C; Nishiyama, H; Rauf, G C; Wexler, L F

1998-08-01

Patients with chronic obstructive pulmonary disease are usually excluded from intravenous dipyridamole thallium-201 testing. We developed a nurse-administered protocol to screen and pretreat patients so they could be safely tested. We prospectively screened patients referred for intravenous dipyridamole thallium testing and retrospectively reviewed a comparison group of patients who had undergone intravenous dipyridamole testing before our bronchospasm protocol. We studied 492 consecutive patients referred for intravenous dipyridamole thallium testing, separating those with complete data (n = 451) into two groups: group A (n = 72), patients assessed to be at risk for intravenous dipyridamole-induced bronchospasm who received our bronchospasm treatment protocol; and group B (n = 379), patients assessed to be free of risk, who did not receive our bronchospasm protocol. Group C (n = 89) was a retrospective comparison group of patients who had undergone intravenous dipyridamole testing before initiation of the protocol. Patients were considered at risk for an adverse event if any of the following were present: peak flow < or =400 ml at the time of the test (spirometry by nurse) that increased to >400 ml after bronchodilator treatment, wheezing audible with stethoscope, history of chronic obstructive pulmonary disease or asthma or dyspnea on exertion at less than four blocks, or resting respiratory rate >18 breaths/min. The test was considered contraindicated if resting oxygen saturation was <85%, respiratory rate < or =36 breaths/min, or peak flow measured by peak flowmeter <400 ml after bronchodilator inhalant (albuterol or metaproterenol sulfate by spacer) at a dose of up to six puffs. One minute after injections of thallium-201, patients at risk were given 50 mg aminophylline by slow intravenous injection. We looked for major and minor adverse effects and divided them into three categories: (1) minor events (transient headache, abdominal discomfort, or nausea

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

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): PPAmore » 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.« less

Uptake of Tl-201 in the testes: Implications for radiation dosimetry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stabin, M.G.; Thomas, S.R.; Wilson, R.A.

The radiation dose to the testes from Tl-201 chloride has been an outstanding question for a number of years. Previous studies have presented kinetic data for the testes with percentage uptake ranging over nearly an order of magnitude from 0.15% to 1.2%. Gupta et al. studied the uptake of Tl-201 in testes and reported an uptake of 0.9-1.2%, with no clearance to 24 hours. Use of the value reported by Gupta et al. results in an estimated dose to the testes in the adult of 0.82 mGy/MBq, and causes the testes to be identified as the highest dose organ. Inmore » our crossover study we evaluated Tl-201 uptake in the testes of 28 patients who received Tl-201 chloride plus D-Ribose, an experimental clearance agent, and Tl-201 chloride plus a placebo 7 to 14 days later. Quantitative measurements were made under a scintillation camera imaging protocol (following exercise and administration of D-Ribose or the placebo) at approximately 1.5, 4.5, 8, 24, and 48 hr, and 7 to 14 days post injection, during which the isolated testes were shielded from the body background. Images were acquired for 5 minutes at early times and 10 to 15 minutes at the latest time. The data were fit to a two component exponential curve. Uptake and clearance parameters were not significantly different between the two regimens. Mean uptake was 0.31 {plus_minus} 0.11%; the mean residence time in the testes was 0.26 {plus_minus}0.08 hr. The testes dose using this new residence time is about 0.20 mGy/MBq. This estimate should form the basis for testicular radiation dosimetry of Tl-201 chloride.« less

Combined thallium-201 and dynamic iodine-123 iodophenylpentadecanoic acid single-photon emission computed tomography in patients after acute myocardial infarction with effective reperfusion.

PubMed

Richter, W S; Beckmann, S; Cordes, M; Schuppenhauer, T; Schartl, M; Munz, D L

2000-12-01

Considerable derangements of energy metabolism are to be expected during ischemia and reperfusion. In ischemic myocardium, the oxidative degradation of carbohydrates is shifted toward the anaerobic production of lactate and the oxidation of fatty acids is suppressed. The aim of this study was to examine the uptake and metabolism of iodine-123 (123I) iodophenylpentadecanoic acid (IPPA) in stunned myocardium. In 15 patients, SPECT with 201Tl and 123I IPPA as well as echocardiography with low-dose dobutamine stimulation were performed 12 +/- 5 days after myocardial infarction with reperfusion. Follow-up echocardiography was carried out 24 +/- 8 days later for documentation of functional improvement. Uptake of 201Tl and 123I IPPA were obtained in five left ventricular segments, and dynamic SPECT imaging was used for calculation of the fast and the slow components of the biexponential myocardial 123I IPPA clearance. Wall motion improved in 14 of 26 dysfunctional segments (54%). Stunned segments were characterized by a reduced 123I IPPA extraction, a shorter half-life of the fast, and a longer half-life of the slow clearance component. All parameters of the combined 201Tl/123I IPPA study predicted functional recovery with similar accuracies (area under the receiver operator characteristic curves between 0.68 and 0.76; p = NS). Analysis of 201Tl uptake alone could not predict functional recovery in this study. Stunned myocardium is characterized by a disturbance of fatty acid metabolism. For prediction of functional improvement, 123I IPPA imaging added significant diagnostic information.

SU-C-201-04: Quantification of Perfusion Heterogeneity Based On Texture Analysis for Fully Automatic Detection of Ischemic Deficits From Myocardial Perfusion Imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fang, Y; Huang, H; Su, T

Purpose: Texture-based quantification of image heterogeneity has been a popular topic for imaging studies in recent years. As previous studies mainly focus on oncological applications, we report our recent efforts of applying such techniques on cardiac perfusion imaging. A fully automated procedure has been developed to perform texture analysis for measuring the image heterogeneity. Clinical data were used to evaluate the preliminary performance of such methods. Methods: Myocardial perfusion images of Thallium-201 scans were collected from 293 patients with suspected coronary artery disease. Each subject underwent a Tl-201 scan and a percutaneous coronary intervention (PCI) within three months. The PCImore » Result was used as the gold standard of coronary ischemia of more than 70% stenosis. Each Tl-201 scan was spatially normalized to an image template for fully automatic segmentation of the LV. The segmented voxel intensities were then carried into the texture analysis with our open-source software Chang Gung Image Texture Analysis toolbox (CGITA). To evaluate the clinical performance of the image heterogeneity for detecting the coronary stenosis, receiver operating characteristic (ROC) analysis was used to compute the overall accuracy, sensitivity and specificity as well as the area under curve (AUC). Those indices were compared to those obtained from the commercially available semi-automatic software QPS. Results: With the fully automatic procedure to quantify heterogeneity from Tl-201 scans, we were able to achieve a good discrimination with good accuracy (74%), sensitivity (73%), specificity (77%) and AUC of 0.82. Such performance is similar to those obtained from the semi-automatic QPS software that gives a sensitivity of 71% and specificity of 77%. Conclusion: Based on fully automatic procedures of data processing, our preliminary data indicate that the image heterogeneity of myocardial perfusion imaging can provide useful information for automatic

Kinetics and dosimetry of thallium-201 in human testes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rao, D.V.; Shepstone, B.J.; Wilkins, H.B.

Thallous chloride ({sup 201}Tl) is a well-known imaging agent. It has been shown to accumulate in the testes. In view of this, the testicular kinetics of {sup 201}Tl is investigated in humans and the absorbed dose to the organ calculated. Thallous chloride {sup 201}Tl was injected intravenously into four patients for myocardial perfusion studies. After clinical evaluation, the testicular uptake and clearance of {sup 201}Tl were monitored for about 1 wk using a gamma camera. Testicular uptake of {sup 201}Tl was rapid with a mean biological uptake half-time of 0.67 hr and mean biological clearance half-time of 280 hr. Themore » mean maximum testicular uptake of {sup 201}Tl was about 0.4% of the injected activity. These data were utilized to calculate the average absorbed dose to the testes. The absorbed dose to the testes was calculated to be 3.5 x 10{sup {minus}4} Gy/MBq (1.3 rad/mCi) of injected activity. When the relative biological effectiveness of the Auger emitter {sup 201}Tl is taken into account, the equivalent dose to the testes is 9.5 x 10{sup {minus}4} Sv/MBq (3.5 rem/mCi). 14 refs., 1 fig., 2 tabs.« less

Experience of low-dose aminophylline use to relieve minor adverse effects of dipyridamole in patients undergoing stress myocardial perfusion imaging.

PubMed

Lin, Li-Fan; Cheng, Cheng-Yi; Hou, Cheng-Han; Ku, Chih-Hung; Tseng, Neng-Chuan; Shen, Daniel H Y

2014-06-01

Intravenous administration of aminophylline is widely adopted to reverse dipyridamole-related adverse effects (AEs) during stress myocardial perfusion imaging (MPI). The study aimed to investigate the efficacy of lower-dose aminophylline to relieve minor AEs. 2,250 consecutive patients undergoing dipyridamole-stressed MPI were enrolled. Information concerning AE occurrence and dosages of aminophylline was collected to evaluate the efficacy of lower-dose aminophylline. A logistic regression was used to determine independent predictors of dipyridamole-related AE occurrence. No severe AE was noted. Overall mild AE incidence was 37.0% (833/2,250 patients). Initial low-dose (25 mg) aminophylline relieved symptoms in 98.8% of patients with mild AEs (823/833 patients). An extra 25 mg aminophylline sufficed to reverse all such AEs. Mean body mass index (BMI) differed significantly between patients with and without any AE [25.6 vs 25.1 (P = .009)]. There was no significant difference between two subgroups in mean age, male gender prevalence, body height and weight, dipyridamole dose/BMI, or prevalence of significant perfusion defect(s) on MPI. Multivariable logistic regression demonstrated BMI remained the independent predictor of dipyridamole-related AE occurrence (odds ratio 1.028, 95% confidence interval 1.007-1.049, P = .01). Low-dose (≦50 mg, and usually 25 mg) aminophylline seems sufficient to relieve mild dipyridamole-related AEs during stress MPI.

IQ-SPECT for thallium-201 myocardial perfusion imaging: effect of normal databases on quantification.

PubMed

Konishi, Takahiro; Nakajima, Kenichi; Okuda, Koichi; Yoneyama, Hiroto; Matsuo, Shinro; Shibutani, Takayuki; Onoguchi, Masahisa; Kinuya, Seigo

2017-07-01

Although IQ-single-photon emission computed tomography (SPECT) provides rapid acquisition and attenuation-corrected images, the unique technology may create characteristic distribution different from the conventional imaging. This study aimed to compare the diagnostic performance of IQ-SPECT using Japanese normal databases (NDBs) with that of the conventional SPECT for thallium-201 ( 201 Tl) myocardial perfusion imaging (MPI). A total of 36 patients underwent 1-day 201 Tl adenosine stress-rest MPI. Images were acquired with IQ-SPECT at approximately one-quarter of the standard time of conventional SPECT. Projection data acquired with the IQ-SPECT system were reconstructed via an ordered subset conjugate gradient minimizer method with or without scatter and attenuation correction (SCAC). Projection data obtained using the conventional SPECT were reconstructed via a filtered back projection method without SCAC. The summed stress score (SSS) was calculated using NDBs created by the Japanese Society of Nuclear Medicine working group, and scores were compared between IQ-SPECT and conventional SPECT using the acquisition condition-matched NDBs. The diagnostic performance of the methods for the detection of coronary artery disease was also compared. SSSs were 6.6 ± 8.2 for the conventional SPECT, 6.6 ± 9.4 for IQ-SPECT without SCAC, and 6.5 ± 9.7 for IQ-SPECT with SCAC (p = n.s. for each comparison). The SSS showed a strong positive correlation between conventional SPECT and IQ-SPECT (r = 0.921 and p < 0.0001), and the correlation between IQ-SPECT with and without SCAC was also good (r = 0.907 and p < 0.0001). Regarding diagnostic performance, the sensitivity, specificity, and accuracy were 80.8, 78.9, and 79.4%, respectively, for the conventional SPECT; 80.8, 80.3, and 82.0%, respectively, for IQ-SPECT without SCAC; and 88.5, 86.8, and 87.3%, respectively, for IQ-SPECT with SCAC, respectively. The area under the curve obtained via receiver operating

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Forman, M.B.; Sandler, M.P.; Sacks, G.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.

In vivo effects of radioactive properties of Tl-201 on human carbonic anhydrase activity

NASA Astrophysics Data System (ADS)

Sahin, Ali; Senturk, Murat

2017-04-01

Carbonic anhydrase (CA) is a family of metalloenzymes that requires Zn as a cofactor and catalyze the quick conversion of CO2 to HCO3- and H+. Inhibitors of the carbonic anhydrases (CAs) have medical usage of significant diseases such as glaucoma, epilepsy, gastroduodenal ulcers, acid-base disequilibria and neurological disorders. The most useful radioisotope, Tl-201, decays by electron capture, emitting Hg X-rays ( 70-80 keV), and photons of 135 and 167 keV in 10% total abundance. Therefore, it has good imaging characteristics without excessive patient radiation dose. It is the most popular isotope used for thallium 201 nuclear cardiac stress tests. In the present study, In vivo inhibitory effect of Tl-201 (Thallium-201) on human erythrocyte carbonic anhydrase (CA) activity were investigated.

Biokinetics of radiolabeled Iodophenylpentadecanoic acid (I-123-IPPA) and thallium-201 in a rabbit model of chronic myocardial infarction measured using a series of thermoluminescent dosimeters

NASA Astrophysics Data System (ADS)

Medich, David Christopher

1997-09-01

The biokinetics of Iodophenylpentadecanoic acid (123I-IPPA) during a chronic period of myocardial infarction were determined and compared to 201Tl. IPPA was assessed as a perfusion and metabolic tracer in the scintigraphic diagnosis of coronary artery disease. The myocardial clearance kinetics were measured by placing a series of thermoluminescent dosimeters (TLDs) on normal and infarcted tissue to measure the local myocardial activity content over time. The arterial blood pool activity was fit to a bi-exponential function for 201Tl and a tri-exponential function for 123I-IPPA to estimate the left ventricle contribution to TLD response. At equilibrium, the blood pool contribution was estimated experimentally to be less than 5% of the total TLD response. The method was unable to resolve the initial uptake of the imaging agent due in part to the 2 minute TLD response integration time and in part to the 30 second lag time for the first TLD placement. A noticeable disparity was observed between the tracer concentrations of IPPA in normal and ischemic tissue of approximately 2:1. The fitting parameters (representing the biokinetic eigenvalue rate constants) were related to the fundamental rate constants of a recycling biokinetic model. The myocardial IPPA content within normal tissue was elevated after approximately 130 minutes post injection. This phenomenon was observed in all but one (950215) of the IPPA TLD kinetics curves.

Present assessment of myocardial viability by nuclear imaging.

PubMed

Saha, G B; MacIntyre, W J; Brunken, R C; Go, R T; Raja, S; Wong, C O; Chen, E Q

1996-10-01

Prospective delineation of viable from nonviable myocardium in patients with coronary artery disease in an important factor in deciding whether a patient should be revascularized or treated medically. Two common techniques--single-photon emission computed tomography (SPECT) and positron-emission computed tomography (PET)--are used in nuclear medicine using various radiopharmaceuticals for the detection of myocardial viability in patients. Thallium-201 (201Tl) and technetium-99m (99mTc)-sestamibi are the common radiopharmaceuticals used in different protocols using SPECT, whereas fluoride-18 (18F)-fluorodeoxyglucose (FDG) and rubidium-82 (82Rb) are most widely used in PET. The SPECT protocols involve stress/redistribution, stress/redistribution/reinjection, and rest/redistribution imaging techniques. Many studies have compared the results of 201Tl and (99mTc)-sestamibi SPECT with those of FDG PET; in some studies, concordant results have been found between delayed thallium and FDG results, indicating that 201Tl, although considered a perfusion agent, shows myocardial viability. Discordant results in a number of studies have been found between sestamibi and FDG, suggesting that the efficacy of sestamibi as a viability marker has yet to be established. Radiolabeled fatty acids such as iodine-123 (123I)-para-iodophenylpentadecanoic acid and carbon-11 (11C)-palmitic acid have been used for the assessment of myocardial viability with limited success. 11C-labeled acetate is a good marker of oxidative metabolism in the heart and has been used to predict the reversibility of wall motion abnormalities. (18F)-FDG is considered the marker of choice for myocardial viability, although variable results are obtained under different physiological conditions. Detection of myocardial viability can be greatly improved by developing new equipment and radiopharmaceuticals of better quality.

Myocardial contusion in patients with blunt chest trauma as evaluated by thallium 201 myocardial scintigraphy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bodin, L.; Rouby, J.J.; Viars, P.

1988-07-01

Fifty five patients suffering from blunt chest trauma were studied to assess the diagnosis of myocardial contusion using thallium 201 myocardial scintigraphy. Thirty-eight patients had consistent scintigraphic defects and were considered to have a myocardial contusion. All patients with scintigraphic defects had paroxysmal arrhythmias and/or ECG abnormalities. Of 38 patients, 32 had localized ST-T segment abnormalities; 29, ST-T segment abnormalities suggesting involvement of the same cardiac area as scintigraphic defects; 21, echocardiographic abnormalities. Sixteen patients had segmental hypokinesia involving the same cardiac area as the scintigraphic defects. Fifteen patients had clinical signs suggestive of myocardial contusion and scintigraphic defects. Almostmore » 70 percent of patients with blunt chest trauma had scintigraphic defects related to areas of myocardial contusion. When thallium 201 myocardial scintigraphy directly showed myocardial lesion, two-dimensional echocardiography and standard ECG detected related functional consequences of cardiac trauma.« less

Relation between thallium-201/iodine 123-BMIPP subtraction and fluorine 18 deoxyglucose polar maps in patients with hypertrophic cardiomyopathy.

PubMed

Ito, Y; Hasegawa, S; Yamaguchi, H; Yoshioka, J; Uehara, T; Nishimura, T

2000-01-01

Clinical studies have shown discrepancies in the distribution of thallium-201 and iodine 123-beta-methyl-iodophenylpentadecanoic acid (BMIPP) in patients with hypertrophic cardiomyopathy (HCM). Myocardial uptake of fluorine 18 deoxyglucose (FDG) is increased in the hypertrophic area in HCM. We examined whether the distribution of a Tl-201/BMIPP subtraction polar map correlates with that of an FDG polar map. We normalized to maximum count each Tl-201 and BMIPP bull's-eye polar map of 6 volunteers and obtained a standard Tl-201/BMIPP subtraction polar map by subtracting a normalized BMIPP bull's-eye polar map from a normalized Tl-201 bull's-eye polar map. The Tl-201/BMIPP subtraction polar map was then applied to 8 patients with HCM (mean age 65+/-12 years) to evaluate the discrepancy between Tl-201 and BMIPP distribution. We compared the Tl-201/BMIPP subtraction polar map with an FDG polar map. In patients with HCM, the Tl-201/BMIPP subtraction polar map showed a focal uptake pattern in the hypertrophic area similar to that of the FDG polar map. By quantitative analysis, the severity score of the Tl-201/BMIPP subtraction polar map was significantly correlated with the percent dose uptake of the FDG polar map. These results suggest that this new quantitative method may be an alternative to FDG positron emission tomography for the routine evaluation of HCM.

Dipyridamole stress myocardial perfusion by computed tomography in patients with left bundle branch block.

PubMed

Cabeda, Estêvan Vieira; Falcão, Andréa Maria Gomes; Soares, José; Rochitte, Carlos Eduardo; Nomura, César Higa; Ávila, Luiz Francisco Rodrigues; Parga, José Rodrigues

2015-12-01

Functional tests have limited accuracy for identifying myocardial ischemia in patients with left bundle branch block (LBBB). To assess the diagnostic accuracy of dipyridamole-stress myocardial computed tomography perfusion (CTP) by 320-detector CT in patients with LBBB using invasive quantitative coronary angiography (QCA) (stenosis ≥ 70%) as reference; to investigate the advantage of adding CTP to coronary computed tomography angiography (CTA) and compare the results with those of single photon emission computed tomography (SPECT) myocardial perfusion scintigraphy. Thirty patients with LBBB who had undergone SPECT for the investigation of coronary artery disease were referred for stress tomography. Independent examiners performed per-patient and per-coronary territory assessments. All patients gave written informed consent to participate in the study that was approved by the institution's ethics committee. The patients' mean age was 62 ± 10 years. The mean dose of radiation for the tomography protocol was 9.3 ± 4.6 mSv. With regard to CTP, the per-patient values for sensitivity, specificity, positive and negative predictive values, and accuracy were 86%, 81%, 80%, 87%, and 83%, respectively (p = 0.001). The per-territory values were 63%, 86%, 65%, 84%, and 79%, respectively (p < 0.001). In both analyses, the addition of CTP to CTA achieved higher diagnostic accuracy for detecting myocardial ischemia than SPECT (p < 0.001). The use of the stress tomography protocol is feasible and has good diagnostic accuracy for assessing myocardial ischemia in patients with LBBB.

Thallium-201 scintigraphy in the diagnosis and management of myocardial sarcoidosis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fields, C.L.; Ossorio, M.A.; Roy, T.M.

1990-03-01

We have described three patients with clinical evidence of myocardial sarcoidosis to illustrate the utility of thallium-201 scintigraphy in demonstrating the myocardial lesions. Both the symptomatic and asymptomatic individuals studied showed the characteristic reverse redistribution phenomenon. No abnormalities were seen during the exercise phase of the thallium study, but myocardial defects were detected in each patient when repeat studies were obtained at rest six hours later. Steroid therapy resolved the defects in each case. We propose thallium-201 scintigraphy of the heart as a safe and useful tool for documenting myocardial involvement in sarcoidosis and following the effects of therapy.

[Performance of Thallium 201 rest-redistribution spect to predict viability in recent myocardial infarction].

PubMed

Coll, Claudia; González, Patricio; Massardo, Teresa; Sierralta, Paulina; Humeres, Pamela; Jofré, Josefina; Yovanovich, Jorge; Aramburú, Ivonne; Brugère, Solange; Chamorro, Hernán; Ramírez, Alfredo; Kunstmann, Sonia; López, Héctor

2002-03-01

The detection of viability after acute myocardial infarction is primordial to select the most appropriate therapy, to decrease cardiac events and abnormal remodeling. Thallium201 SPECT is one of the radionuclide techniques used to detect viability. To evaluate the use of Thallium201 rest-redistribution SPECT to detect myocardial viability in reperfused patients after a recent myocardial infarction. Forty one patients with up to of 24 days of evolution of a myocardial infarction were studied. All had angiographically demonstrated coronary artery disease and were subjected to a successful thrombolysis, angioplasty or bypass grafting. SPECT Thallium201 images were acquired at rest and after 4 h of redistribution. These results were compared with variations in wall motion score, studied at baseline and after 3 or 4 months with echocardiography. The sensitivity of rest-redistribution Thallium201 SPECT, to predict recovery of wall motion was 91% when patient analysis was performed and 79% when segmental analysis was done in the culprit region. The figures for specificity were 56 and 73% respectively. Rest-distribution Thallium201 SPECT has an excellent sensitivity to predict myocardial viability in recent myocardial infarction. The data obtained in this study is similar to that reported for chronic coronary artery disease.

Comparison of the myocardial blood flow response to regadenoson and dipyridamole: a quantitative analysis in patients referred for clinical 82Rb myocardial perfusion PET.

PubMed

Goudarzi, Behnaz; Fukushima, Kenji; Bravo, Paco; Merrill, Jennifer; Bengel, Frank M

2011-10-01

Regadenoson is a novel selective A2A adenosine receptor agonist, which is administered as an intravenous bolus at a fixed dose. It is currently not clear if the absolute flow increase in response to this fixed dose is a function of distribution volume in individual patients or if it is generally comparable to the previous standard agents dipyridamole or adenosine, which are dosed based on weight. We used quantitative analysis of clinical 82Rb PET/CT studies to obtain further insights. A total of 104 subjects with normal clinical rest/stress 82Rb perfusion PET/CT were included in a retrospective analysis. To rule out confounding factors, none had evidence of prior cardiac disease, ischaemia or infarction, cardiomyopathy, diabetes with insulin use, calcium score>400, renal disease or other significant systemic disease. A group of 52 patients stressed with regadenoson were compared with a group of 52 patients stressed with dipyridamole before regadenoson became available. The groups were matched for clinical characteristics, risk factors and baseline haemodynamics. Myocardial blood flow (MBF) and myocardial flow reserve (MFR) were quantified using a previously validated retention model, after resampling of dynamic studies from list-mode 82Rb datasets. At rest, heart rate, blood pressure and MBF were comparable between the groups. Regadenoson resulted in a significantly higher heart rate (34±14 vs. 23±10 beats per minute increase from baseline; p<0.01) and rate-pressure product. Patients in the regadenoson group reported less severe symptoms and required less aminophylline. Stress MBF and MFR were not different between the groups (2.2±0.6 vs. 2.1±0.6 ml/min/g, p=0.39, and 2.9±0.8 vs. 2.8±0.7, p=0.31, respectively). In the regadenoson group, there was no correlation between stress flow or MFR and body weight or BMI. Despite its administration at a fixed dose, regadenoson results in an absolute increase in MBF which is comparable to that following dipyridamole

123I-BMIPP fatty acid analogue imaging is a novel diagnostic and prognostic approach following acute myocardial infarction.

PubMed

Biswas, S K; Sarai, M; Hishida, H; Ozaki, Y

2009-10-01

Fatty acid oxidation is the most efficient mode of myocardial energy production which requires a large amount of oxygen. Thus, alteration of fatty acid oxidation is considered to be a sensitive marker of ischaemia and myocardial damage. (123)I-BMIPP ([123]I-beta-methyl-p-iodophenylpentadecanoic acid) is a newly-investigated single-photon branching free fatty acid radiopharmaceutical with slow metabolism; thus, it is well-suited for single-photon emission computed tomography (SPECT). Assessment of fatty acid metabolism by radionuclide techniques has a potential role for the early detection of myocardial ischaemia and the assessment of the severity of ischaemic heart disease. Although stable patients with a healed myocardial infarction may have a relatively good prognosis, risk stratification in the predischarge period should be valuable for deciding upon appropriate management. In this respect, the presence of discordant BMIPP uptake relative to (201)Tl perfusion appears to be the best predictor of future cardiac events among all other cardiovascular imaging modalities. Since discordant BMIPP uptake correlates well with redistribution on stress (201)Tl imaging and perfusion-metabolism mismatch on positron emission tomography, it is considered that such BMIPP and (201)Tl discordance may identify a high-risk subgroup among patients with acute myocardial infarction. A BMIPP scan may reflect prior severe ischaemia after recovery of perfusion, the so-called "ischaemic memory". Gated BMIPP SPECT has been recently introduced for simultaneous assessment of myocardial metabolism and ventricular function. Such a new technique seems to be valuable for a better understanding of the pathophysiological state of heart failure and cardiomyopathy.

Nuclear myocardial perfusion imaging using thallium-201 with a novel multifocal collimator SPECT/CT: IQ-SPECT versus conventional protocols in normal subjects.

PubMed

Matsuo, Shinro; Nakajima, Kenichi; Onoguchi, Masahisa; Wakabayash, Hiroshi; Okuda, Koichi; Kinuya, Seigo

2015-06-01

A novel multifocal collimator, IQ-SPECT (Siemens) consists of SMARTZOOM, cardio-centric and 3D iterative SPECT reconstruction and makes it possible to perform MPI scans in a short time. The aims are to delineate the normal uptake in thallium-201 ((201)Tl) SPECT in each acquisition method and to compare the distribution between new and conventional protocol, especially in patients with normal imaging. Forty patients (eight women, mean age of 75 years) who underwent myocardial perfusion imaging were included in the study. All patients underwent one-day protocol perfusion scan after an adenosine-stress test and at rest after administering (201)Tl and showed normal results. Acquisition was performed on a Symbia T6 equipped with a conventional dual-headed gamma camera system (Siemens ECAM) and with a multifocal SMARTZOOM collimator. Imaging was performed with a conventional system followed by IQ-SPECT/computed tomography (CT). Reconstruction was performed with or without X-ray CT-derived attenuation correction (AC). Two nuclear physicians blinded to clinical information interpreted all myocardial perfusion images. A semi-quantitative myocardial perfusion was analyzed by a 17-segment model with a 5-point visual scoring. The uptake of each segment was measured and left ventricular functions were analyzed by QPS software. IQ-SPECT provided good or excellent image quality. The quality of IQ-SPECT images without AC was similar to those of conventional LEHR study. Mid-inferior defect score (0.3 ± 0.5) in the conventional LEHR study was increased significantly in IQ-SPECT with AC (0 ± 0). IQ-SPECT with AC improved the mid-inferior decreased perfusion shown in conventional images. The apical tracer count in IQ-SPECT with AC was decreased compared to that in LEHR (0.1 ± 0.3 vs. 0.5 ± 0.7, p < 0.05). The left ventricular ejection fraction from IQ-SPECT was significantly higher than that from the LEHR collimator (p = 0.0009). The images of IQ-SPECT acquired in a

Optimal reproducibility of gated sestamibi and thallium myocardial perfusion study left ventricular ejection fractions obtained on a solid-state CZT cardiac camera requires operator input.

PubMed

Cherk, Martin H; Ky, Jason; Yap, Kenneth S K; Campbell, Patrina; McGrath, Catherine; Bailey, Michael; Kalff, Victor

2012-08-01

To evaluate the reproducibility of serial re-acquisitions of gated Tl-201 and Tc-99m sestamibi left ventricular ejection fraction (LVEF) measurements obtained on a new generation solid-state cardiac camera system during myocardial perfusion imaging and the importance of manual operator optimization of left ventricular wall tracking. Resting blinded automated (auto) and manual operator optimized (opt) LVEF measurements were measured using ECT toolbox (ECT) and Cedars-Sinai QGS software in two separate cohorts of 55 Tc-99m sestamibi (MIBI) and 50 thallium (Tl-201) myocardial perfusion studies (MPS) acquired in both supine and prone positions on a cadmium zinc telluride (CZT) solid-state camera system. Resting supine and prone automated LVEF measurements were similarly obtained in a further separate cohort of 52 gated cardiac blood pool scans (GCBPS) for validation of methodology and comparison. Appropriate use of Bland-Altman, chi-squared and Levene's equality of variance tests was used to analyse the resultant data comparisons. For all radiotracer and software combinations, manual checking and optimization of valve planes (+/- centre radius with ECT software) resulted in significant improvement in MPS LVEF reproducibility that approached that of planar GCBPS. No difference was demonstrated between optimized MIBI/Tl-201 QGS and planar GCBPS LVEF reproducibility (P = .17 and P = .48, respectively). ECT required significantly more manual optimization compared to QGS software in both supine and prone positions independent of radiotracer used (P < .02). Reproducibility of gated sestamibi and Tl-201 LVEF measurements obtained during myocardial perfusion imaging with ECT toolbox or QGS software packages using a new generation solid-state cardiac camera with improved image quality approaches that of planar GCBPS however requires visual quality control and operator optimization of left ventricular wall tracking for best results. Using this superior cardiac technology, Tl-201

Myocardial Blood Volume Is Associated with Myocardial Oxygen Consumption: An Experimental Study with CMR in a Canine Model

PubMed Central

McCommis, Kyle S.; Zhang, Haosen; Goldstein, Thomas A.; Misselwitz, Bernd; Abendschein, Dana R.; Gropler, Robert J.; Zheng, Jie

2009-01-01

OBJECTIVES To evaluate the feasibility of cardiovascular MR (CMR) to determine regional myocardial perfusion and O2 metabolism, and assess the role of myocardial blood volume (MBV) on oxygen supply. BACKGROUND Coronary artery disease presents as an imbalance of myocardial oxygen supply and demand. We have developed relevant CMR methods to determine the relationship of myocardial blood flow (MBF) and MBV to oxygen consumption (MVO2) during pharmacologic hyperemia. METHODS Twenty-one mongrel dogs were studied with varying stenosis severities imposed on the proximal left anterior descending (LAD) coronary artery. MBF and MBV were determined by CMR first-pass perfusion, while the oxygen extraction fraction (OEF) and MVO2 were determined by the myocardial Blood-Oxygen-Level-Dependent (BOLD) effect and Fick’s law, respectively. MR imaging was performed at rest, and during either dipyridamole-induced vasodilation or dobutamine-induced hyperemia. Regional differences in myocardial perfusion and oxygenation were then evaluated. RESULTS Dipyridamole and dobutamine both led to 145–200% increases in MBF and 50–80% increases in MBV in normal perfused myocardium. As expected, MVO2 increased more significantly with dobutamine (~175%) than dipyridamole (~40%). Coronary stenosis resulted in an attenuation of MBF, MBV, and MVO2 in both the LAD-subtended stenosis region and the left circumflex subtended remote region. Liner regression analysis showed that MBV reserve appears to be more correlated with MVO2 reserve during dobutamine stress than MBF reserve, particularly in the stenotic regions. Conversely, MBF reserve appears to be more correlated with MVO2 reserve during dipyridamole, although neither of these differences was significant. CONCLUSIONS Noninvasive evaluation of both myocardial perfusion and oxygenation by CMR facilitates direct monitoring of regional myocardial ischemia and provides a valuable tool for better understanding microvascular pathophysiology. These

Dipyridamole for preventing recurrent ischemic stroke and other vascular events: a meta-analysis of individual patient data from randomized controlled trials.

PubMed

Leonardi-Bee, Jo; Bath, Philip M W; Bousser, Marie-Germaine; Davalos, Antoni; Diener, Hans-Christoph; Guiraud-Chaumeil, Bernard; Sivenius, Juhani; Yatsu, Frank; Dewey, Michael E

2005-01-01

Results from randomized controlled trials of dipyridamole, given with or without aspirin, for secondary prevention after ischemic stroke or transient ischemic attack (TIA) have given conflicting results. We performed a meta-analysis using individual patient data from relevant randomized controlled trials. Randomized controlled trials involving dipyridamole in patients with previous ischemic stroke or TIA were sought from searches of the Cochrane Library, other electronic databases, references lists, earlier reviews, and contact with the manufacturer of dipyridamole. Individual patient data were merged from 5 of 7 relevant trials involving 11 459 patients. Results were adjusted for age, gender, qualifying event, and history of previous hypertension. Recurrent stroke was reduced by dipyridamole as compared with control (OR, 0.82; 95% CI, 0.68 to 1.00), and by combined aspirin and dipyridamole versus aspirin alone (OR, 0.78; 95% CI, 0.65 to 0.93), dipyridamole alone (OR, 0.74; 95% CI, 0.60 to 0.90), or control (OR, 0.61; 95% CI, 0.51 to 0.71). The point estimates obtained for the comparisons of aspirin and dipyridamole versus control (OR, 0.63; significant) or versus aspirin (OR, 0.88; nonsignificant) were similar if the data from the largest trial, ESPS II (which provided 57% of data), were excluded. Similar findings were observed for nonfatal stroke. The combination of aspirin and dipyridamole also significantly reduced the composite outcome of nonfatal stroke, nonfatal myocardial infarction, and vascular death as compared with aspirin alone (OR, 0.84; 95% CI, 0.72 to 0.97), dipyridamole alone (OR, 0.76; 95% CI, 0.64 to 0.90), or control (OR, 0.66; 95% CI, 0.57 to 0.75). Vascular death was not altered in any group. Dipyridamole, given alone or with aspirin, reduces stroke recurrence in patients with previous ischemic cerebrovascular disease. The combination of aspirin and dipyridamole also reduces the composite of nonfatal stroke, nonfatal myocardial infarction, and

Creation and characterization of normal myocardial perfusion imaging databases using the IQ·SPECT system.

PubMed

Okuda, Koichi; Nakajima, Kenichi; Matsuo, Shinro; Kondo, Chisato; Sarai, Masayoshi; Horiguchi, Yoriko; Konishi, Takahiro; Onoguchi, Masahisa; Shimizu, Takeshi; Kinuya, Seigo

2017-01-03

Image acquisition by short-time single-photon emission-computed tomography (SPECT) has been made feasible by IQ·SPECT. The aim of this study was to generate normal databases (NDBs) of thallium-201 ( 201 Tl) myocardial perfusion imaging for IQ·SPECT, and characterize myocardial perfusion distribution. We retrospectively enrolled 159 patients with a low likelihood of cardiac diseases from four hospitals in Japan. All patients underwent short-time 201 Tl myocardial perfusion IQ·SPECT with or without attenuation and scatter correction (ACSC) in either supine or prone position. The mean myocardial counts were calculated using 17-segment polar maps. Three NDBs were derived from supine and prone images as well as supine images with ACSC. Differences between the supine and prone positions were observed in the uncorrected sex-segregated NDBs in the mid-inferolateral counts (p ≤ 0.016 for males and p ≤ 0.002 for females). Differences between IQ·SPECT and conventional SPECT were also observed in the mid-anterior, inferolateral, and apical lateral counts (p ≤ 0.009 for males and p ≤ 0.003 for females). Apical low counts attributed to myocardial thinning were observed in the apical anterior and apex segments in the supine IQ·SPECT NDB with ACSC. There were significant differences between uncorrected supine and prone NDBs, between uncorrected supine NDB and supine NDB with ACSC, and between uncorrected supine NDB and conventional SPECT NDB. Understanding the pattern of normal distribution in IQ-SPECT short-time acquisitions with and without ACSC will be helpful for interpretation of imaging findings in patients with coronary artery disease (CAD) or low likelihood of CAD and the NDBs will aid in quantitative analysis.

Myocardial perfusion imaging with thallium-201: correlation with coronary arteriography and electrocardiography

PubMed Central

Sternberg, Leonard; Wald, Robert W.; Feiglin, David H.I.; Morch, John E.

1978-01-01

Myocardial perfusion imaging with thallium-201 and electrocardiography with the subject at rest and undergoing submaximal treadmill exercise were performed in 19 men and 3 women. Selective coronary arteriography and left ventriculography showed that 7 had normal coronary arteries and 15 had coronary artery disease. The 11 persons with electrocardiographic evidence of an old myocardial infarct (q waves) had a perfusion defect at rest in the area of the infarct and a segmental abnormality of wall motion apparent on the left ventriculogram corresponding to the perfusion defect. Myocardial perfusion imaging and electrocardiography were equally sensitive in detecting coronary artery disease in exercising individuals: perfusion defects were noted in 7 of the 15 persons with coronary artery disease, and diagnostic ST-segment depression was present in 8 of the 15. Combination of the results of the two tests with exercise permitted the identification of 11 of the 15 persons and improved the sensitivity. Combination of the results of rest and exercise imaging and electrocardiography permitted the identification of 94% of the patients with coronary artery disease. Myocardial perfusion imaging with 201TI in the subject at rest is a sensitive indicator of previous myocardial infarction. Imaging after the subject has exercised is a useful adjunct to conventional exercise electrocardiography, especially in those whose exercise electrocardiogram is non-interpretable. ImagesFIG. 1FIG. 2FIG. 3FIG. 4FIG. 5 PMID:630487

Optimization and comparison of simultaneous and separate acquisition protocols for dual isotope myocardial perfusion SPECT.

PubMed

Ghaly, Michael; Links, Jonathan M; Frey, Eric C

2015-07-07

Dual-isotope simultaneous-acquisition (DISA) rest-stress myocardial perfusion SPECT (MPS) protocols offer a number of advantages over separate acquisition. However, crosstalk contamination due to scatter in the patient and interactions in the collimator degrade image quality. Compensation can reduce the effects of crosstalk, but does not entirely eliminate image degradations. Optimizing acquisition parameters could further reduce the impact of crosstalk. In this paper we investigate the optimization of the rest Tl-201 energy window width and relative injected activities using the ideal observer (IO), a realistic digital phantom population and Monte Carlo (MC) simulated Tc-99m and Tl-201 projections as a means to improve image quality. We compared performance on a perfusion defect detection task for Tl-201 acquisition energy window widths varying from 4 to 40 keV centered at 72 keV for a camera with a 9% energy resolution. We also investigated 7 different relative injected activities, defined as the ratio of Tc-99m and Tl-201 activities, while keeping the total effective dose constant at 13.5 mSv. For each energy window and relative injected activity, we computed the IO test statistics using a Markov chain Monte Carlo (MCMC) method for an ensemble of 1,620 triplets of fixed and reversible defect-present, and defect-absent noisy images modeling realistic background variations. The volume under the 3-class receiver operating characteristic (ROC) surface (VUS) was estimated and served as the figure of merit. For simultaneous acquisition, the IO suggested that relative Tc-to-Tl injected activity ratios of 2.6-5 and acquisition energy window widths of 16-22% were optimal. For separate acquisition, we observed a broad range of optimal relative injected activities from 2.6 to 12.1 and acquisition energy window of widths 16-22%. A negative correlation between Tl-201 injected activity and the width of the Tl-201 energy window was observed in these ranges. The results

Optimization and comparison of simultaneous and separate acquisition protocols for dual isotope myocardial perfusion SPECT

PubMed Central

Ghaly, Michael; Links, Jonathan M; Frey, Eric C

2015-01-01

Dual-isotope simultaneous-acquisition (DISA) rest-stress myocardial perfusion SPECT (MPS) protocols offer a number of advantages over separate acquisition. However, crosstalk contamination due to scatter in the patient and interactions in the collimator degrade image quality. Compensation can reduce the effects of crosstalk, but does not entirely eliminate image degradations. Optimizing acquisition parameters could further reduce the impact of crosstalk. In this paper we investigate the optimization of the rest Tl-201 energy window width and relative injected activities using the ideal observer (IO), a realistic digital phantom population and Monte Carlo (MC) simulated Tc-99m and Tl-201 projections as a means to improve image quality. We compared performance on a perfusion defect detection task for Tl-201 acquisition energy window widths varying from 4 to 40 keV centered at 72 keV for a camera with a 9% energy resolution. We also investigated 7 different relative injected activities, defined as the ratio of Tc-99m and Tl-201 activities, while keeping the total effective dose constant at 13.5 mSv. For each energy window and relative injected activity, we computed the IO test statistics using a Markov chain Monte Carlo (MCMC) method for an ensemble of 1,620 triplets of fixed and reversible defect-present, and defect-absent noisy images modeling realistic background variations. The volume under the 3-class receiver operating characteristic (ROC) surface (VUS) was estimated and served as the figure of merit. For simultaneous acquisition, the IO suggested that relative Tc-to-Tl injected activity ratios of 2.6–5 and acquisition energy window widths of 16–22% were optimal. For separate acquisition, we observed a broad range of optimal relative injected activities from 2.6 to 12.1 and acquisition energy window of widths 16–22%. A negative correlation between Tl-201 injected activity and the width of the Tl-201 energy window was observed in these ranges. The results

Monte Carlo evaluation of accuracy and noise properties of two scatter correction methods for /sup 201/Tl cardiac SPECT

NASA Astrophysics Data System (ADS)

Narita, Y.; Iida, H.; Ebert, S.; Nakamura, T.

1997-12-01

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 three numerical phantoms for /sup 201/Tl. Data were reconstructed with ordered-subset EM algorithm including noise-less transmission data based attenuation correction. Accuracy of TDCS and TEW scatter corrections were assessed by comparison with simulated true primary data. The uniform cylindrical phantom simulation demonstrated better quantitative accuracy with TDCS than with TEW (-2.0% vs. 16.7%) and better S/N (6.48 vs. 5.05). A uniform ring myocardial phantom simulation demonstrated better homogeneity with TDCS than TEW in the myocardium; i.e., anterior-to-posterior wall count ratios were 0.99 and 0.76 with TDCS and TEW, respectively. For the MCAT phantom, 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.

A preliminary feasibility study of simultaneous dual-isotope imaging with a solid-state dedicated cardiac camera for evaluating myocardial perfusion and fatty acid metabolism.

PubMed

Ko, Toshiyuki; Utanohara, Yuko; Suzuki, Yasuhiro; Kurihara, Makiko; Iguchi, Nobuo; Umemura, Jun; Sumiyoshi, Tetsuya; Tomoike, Hitonobu

2016-01-01

Simultaneous dual-isotope SPECT imaging with 201Tl and (123)I-β-methyl-p-iodophenylpentadecanoic acid (BMIPP) is used to study the perfusion-metabolism mismatch. It predicts post-ischemic functional recovery by detecting stunned myocardium. On the other hand, (99m)Tc-MIBI is another radioisotope widely used in myocardial perfusion imaging because of its better image quality and lower radiation exposure than 201Tl. However, since the photopeak energies of (99m)Tc and (123)I are very similar, crosstalk hampers the simultaneous use of these two radioisotopes. To overcome this problem, we conducted simultaneous dual-isotope imaging study using the D-SPECT scanner (Spectrum-Dynamics, Israel) which has a novel detector design and excellent energy resolution. We first conducted a basic experiment using cardiac phantom to simulate the condition of normal perfusion and impaired fatty acid metabolism. Subsequently, we prospectively recruited 30 consecutive patients who underwent successful percutaneous coronary intervention for acute myocardial infarction, and performed (99m)Tc-MIBI/(123)I-BMIPP dual-isotope imaging within 5 days after reperfusion. Images were interpreted by two experienced cardiovascular radiologists to identify the infarcted and stunned areas based on the coronary artery territories. As a result, cardiac phantom experiment revealed no significant crosstalk between (99m)Tc and (123)I. In the subsequent clinical study, (99m)Tc-MIBI/(123)I-BMIPP dual-isotope imaging in all participant yielded excellent image quality and detected infarcted and stunned areas correctly when compared with coronary angiographic findings. Furthermore, we were able to reduce radiation exposure to significantly approximately one-eighth. In conclusion, we successfully demonstrated the practical application of simultaneous assessment of myocardial perfusion and fatty acid metabolism by (99m)Tc-MIBI and (123)I-BMIPP using a D-SPECT cardiac scanner. Compared with conventional (201)Tl

Reduced coronary flow and resistance reserve in primary scleroderma myocardial disease

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nitenberg, A.; Foult, J.M.; Kahan, A.

1986-08-01

The maximum coronary vasodilator capacity after intravenous dipyridamole (0.14 mg X kg-1 X min-1 X 4 minutes) was studied in seven patients with primary scleroderma myocardial disease and compared to that of seven control subjects. Hemodynamic data and left ventricular angiographic data were not different in the two groups. The coronary flow reserve was evaluated by the dipyridamole/basal coronary sinus blood flow ratio (D/B CSBF) and the coronary resistance reserve by the dipyridamole/basal coronary resistance ratio (D/B CR). Coronary reserve was greatly impaired in the group with primary scleroderma myocardial disease: D/B CSBF was lower than in the control groupmore » (2.54 +/- 1.37 vs 4.01 +/- 0.56, respectively; p less than 0.05) and D/B CR was higher than in the control group (0.47 +/- 0.25 vs 0.23 +/- 0.04, respectively; p less than 0.05). Such a decreased coronary flow and resistance reserve in patients with primary scleroderma myocardial disease was not explained by an alteration of left ventricular function. It may be an important contributing factor in the pathogenesis of primary scleroderma myocardial disease.« less

Normal results of post-race thallium-201 myocardial perfusion imaging in marathon runners with elevated serum MB creatine kinase levels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Siegel, A.J.; Silverman, L.M.; Holman, B.L.

1985-10-01

Elevated cardiac enzyme values in asymptomatic marathon runners after competition can arise from skeletal muscle through exertional rhabdomyolysis, silent injury to the myocardium, or a combined tissue source. Peak post-race levels of the MB isoenzyme of creatine kinase are similar to values in patients with acute myocardial infarction. Previously reported normal results of infarct-avid myocardial scintigraphy with technetium 99m pyrophosphate in runners after competition suggest a non-cardiac source but cannot exclude silent injury to the myocardium. Therefore, thallium 201 myocardial perfusion imaging was performed in runners immediately after competition together with determination of sequential cardiac enzyme levels. Among 15 runnersmore » tested, the average peak in serum MB creatine kinase 24 hours after the race was 128 IU/liter with a cumulative MB creatine kinase release of 117 IU/liter; these values are comparable to those in patients with acute transmural myocardial infarction. Thallium 201 myocardial scintigraphic results were normal in five runners randomly selected from those who volunteered for determination of sequential blood levels. It is concluded that elevations of serum MB creatine kinase in marathon runners arise from a skeletal muscle source and that thallium 201 myocardial scintigraphy is useful to assess runners for myocardial injury when clinical questions arise.« less

Comparison between stress myocardial perfusion SPECT recorded with cadmium-zinc-telluride and Anger cameras in various study protocols.

PubMed

Verger, Antoine; Djaballah, Wassila; Fourquet, Nicolas; Rouzet, François; Koehl, Grégoire; Imbert, Laetitia; Poussier, Sylvain; Fay, Renaud; Roch, Véronique; Le Guludec, Dominique; Karcher, Gilles; Marie, Pierre-Yves

2013-02-01

The results of stress myocardial perfusion SPECT could be enhanced by new cadmium-zinc-telluride (CZT) cameras, although differences compared to the results with conventional Anger cameras remain poorly known for most study protocols. This study was aimed at comparing the results of CZT and Anger SPECT according to various study protocols while taking into account the influence of obesity. The study population, which was from three different institutions equipped with identical CZT cameras, comprised 276 patients referred for study using protocols involving (201)Tl (n = 120) or (99m)Tc-sestamibi injected at low dose at stress ((99m)Tc-Low; stress/rest 1-day protocol; n = 110) or at high dose at stress ((99m)Tc-High; rest/stress 1-day or 2-day protocol; n = 46). Each Anger SPECT scan was followed by a high-speed CZT SPECT scan (2 to 4 min). Agreement rates between CZT and Anger SPECT were good irrespective of the study protocol (for abnormal SPECT, (201)Tl 92 %, (99m)Tc-Low 86 %, (99m)Tc-High 98 %), although quality scores were much higher for CZT SPECT with all study protocols. Overall correlations were high for the extent of myocardial infarction (r = 0.80) and a little lower for ischaemic areas (r = 0.72), the latter being larger on Anger SPECT (p < 0.001). This larger extent was mainly observed in 50 obese patients who were in the (201)Tl or (99m)Tc-Low group and in whom stress myocardial counts were particularly low with Anger SPECT (228 ± 101 kcounts) and dramatically enhanced with CZT SPECT (+279 ± 251 %). Concordance between the results of CZT and Anger SPECT is good regardless of study protocol and especially when excluding obese patients who have low-count Anger SPECT and for whom myocardial counts are dramatically enhanced on CZT SPECT.

Myocardial Perfusion SPECT 2015 in Germany

PubMed Central

Burchert, Wolfgang; Schäfer, Wolfgang; Hacker, Marcus

2016-01-01

Summary Aim The working group Cardiovascular Nuclear Medicine of the German Society of Nuclear Medicine presents the results of the 7th survey of myocardial perfusion SPECT (MPS) of the reporting year 2015. Method 268 questionnaires (173 practices [PR], 67 hospitals [HO], 28 university hospitals [UH]) were evaluated. Results of the last survey from 2012 are set in squared brackets. Results MPS of 121 939 [105 941] patients were reported. 98 % [95 %] of all MPS were performed with Tc-99m radiopharmaceuticals and 2 % [5 %] with Tl-201. 78 % [79 %] of all patients were studied in PR, 14 % [15 %] in HO, and 8 % [6 %] in UH. A pharmacological stress test was performed in 43 % [39 %] (22 % [24 %] adenosine, 20 % [9 %] regadenoson, 1% [6 %] dipyridamole or dobutamine). Attenuation correction was applied in 25 % [2009: 10 %] of MPS. Gated SPECT was performed in 78 % [70 %] of all rest MPS, in 80 % [73 %] of all stress and in 76 % [67 %] of all stress and rest MPS. 53 % [33 %] of all nuclear medicine departments performed MPS scoring by default, whereas 24 % [41 %] did not apply any quantification. 31 % [26 %] of all departments noticed an increase in their counted MPS and 29 % [29 %] no changes. Data from 89 departments which participated in all surveys showed an increase in MPS count of 11.1 % (PR: 12.2 %, HO: 4.8 %, UH: 18.4 %). 70 % [60 %] of the MPS were requested by ambulatory care cardiologists. Conclusion The 2015 MPS survey reveals a high-grade adherence of routine MPS practice to current guidelines. The positive trend in MPS performance and number of MPS already observed in 2012 continues. Educational training remains necessary in the field of SPECT scoring. PMID:27909712

SPECT Myocardial Blood Flow Quantitation Concludes Equivocal Myocardial Perfusion SPECT Studies to Increase Diagnostic Benefits.

PubMed

Chen, Lung-Ching; Lin, Chih-Yuan; Chen, Ing-Jou; Ku, Chi-Tai; Chen, Yen-Kung; Hsu, Bailing

2016-01-01

Recently, myocardial blood flow quantitation with dynamic SPECT/CT has been reported to enhance the detection of coronary artery disease in human. This advance has created important clinical applications to coronary artery disease diagnosis and management for areas where myocardial perfusion PET tracers are not available. We present 2 clinical cases that undergone a combined test of 1-day rest/dipyridamole-stress dynamic SPECT and ECG-gated myocardial perfusion SPECT scans using an integrated imaging protocol and demonstrate that flow parameters are capable to conclude equivocal myocardial perfusion SPECT studies, therefore increasing diagnostic benefits to add value in making clinical decisions.

[Diagnosis of myocardial infarction by cine MR imaging--a comparative study with thallium-201 myocardial SPECT].

PubMed

Shiozaki, H

1993-01-25

The usefulness of cine magnetic resonance (MR) imaging was evaluated in 41 patients with acute (4 cases), subacute (21 cases) and chronic (16 cases) myocardial infarctions on the basis of the findings of thallium-201 myocardial SPECT. The overall rate of diagnostic accordance between cine MR imaging and SPECT was 85.0% (408/480). It was highest at the middle of the left ventricle (89.0%, 146/164) and lowest at the base (82.7%, 129/156). Measurement of wall thickness using the images printed on films was possible in 87.1% of segments (418/480). There was a significant difference in end-diastolic wall thickness and %-thickening between the infarcted and non-infarcted sites except for the base of the left ventricle. However, diastolic wall thinning was not remarkable in acute cases of less than one week after onset. In these cases %-thickening may be useful. Partial volume averaging on MR imaging and the inaccuracy of SPECT findings at the base also made meaningful comparison difficult. The most important diagnostic findings of myocardial infarction on cine MR imaging were end-diastolic wall thinning and abnormal motion such as akinesis and dyskinesis. It is concluded that cine MR imaging is a useful noninvasive examination method for evaluating the status of cardiac function in myocardial infarction.

Changes of electrocardiogram and hemodynamics in response to dipyridamole: In vivo comparative analyses using anesthetized beagle dogs and microminipigs.

PubMed

Ando, Kentaro; Takahara, Akira; Nakamura, Yuji; Wada, Takeshi; Chiba, Koki; Goto, Ai; Lubna, Nur Jaharat; Hagiwara-Nagasawa, Mihoko; Izumi-Nakaseko, Hiroko; Hoshiai, Kiyotaka; Akie, Yasuki; Naito, Atsuhiko T; Sugiyama, Atsushi

2018-02-01

Microminipigs are expected as a novel animal model for cardiovascular pharmacological experiments. Since inherent vulnerability of coronary circulation of microminipigs has not been characterized, we performed dipyridamole-stress test to both microminipigs and beagle dogs, and compared the results. Dipyridamole in doses of 0.056 and 0.56 mg/kg were intravenously infused over 10 min (n = 4 for each animal). Dipyridamole decreased the systolic/diastolic blood pressures and double product in dogs as well as in microminipigs; but it did not significantly alter the heart rate or the global balance between the myocardial oxygen demand and supply in either animal. While organic coronary arterial stenosis was not detected in either animal, dogs have well-developed epicardial intracoronary networks unlike microminipigs. Like in humans, dipyridamole did not affect the ST segment of microminipigs, whereas it substantially depressed that in dogs. The results indicate the onset of subendocardial ischemia by dipyridamole in dogs may be partly associated with their well-developed native coronary collateral channels. Microminipigs would be more useful to evaluate the drugs which may affect the coronary circulation in the pre-clinical study than dogs. Copyright © 2018 The Authors. Production and hosting by Elsevier B.V. All rights reserved.

Comparison of exercise, dobutamine-atropine and dipyridamole-atropine stress echocardiography in detecting coronary artery disease

PubMed Central

Nedeljkovic, Ivana; Ostojic, Miodrag; Beleslin, Branko; Djordjevic-Dikic, Ana; Stepanovic, Jelena; Nedeljkovic, Milan; Stojkovic, Sinisa; Stankovic, Goran; Saponjski, Jovica; Petrasinovic, Zorica; Giga, Vojislav; Mitrovic, Predrag

2006-01-01

Background Dipyridamole and dobutamine stress echocardiography testing are most widely utilized, but their sensitivity remained suboptimal in comparison to routine exercise stress echocardiography. The aim of our study is to compare, head-to-head, exercise, dobutamine and dipyridamole stress echocardiography tests, performed with state-of-the-art protocols in a large scale prospective group of patients. Methods Dipyridamole-atropine (Dipatro: 0.84 mg/kg over 10 min i.v. dipyridamole with addition of up to 1 mg of atropine), dobutamine-atropine (Dobatro: up to 40 mcg/kg/min i.v. dobutamine with addition of up to 1 mg of atropine) and exercise (Ex, Bruce) were performed in 166 pts. Of them, 117 pts without resting wall motion abnormalities were enrolled in study (91 male; mean age 54 ± 10 years; previous non-transmural myocardial infarction in 32 pts, angina pectoris in 69 pts and atypical chest pain in 16 pts). Tests were performed in random sequence, in 3 different days, within 5 day period under identical therapy. All patients underwent coronary angiography. Results Significant coronary artery disease (CAD; ≥50% diameter stenosis) was present in 69 pts (57 pts 1-vessel CAD, 12 multivessel CAD) and absent in 48 pts. Sensitivity (Sn) was 96%, 93% and 90%, whereas specificity (Sp) was 92%, 92% and 87% for Dobatro, Dipatro and Ex, respectively (p = ns). Concomitant beta blocker therapy did not influence peak rate-pressure product and Sn of Dobatro and Dipatro (p = ns). Conclusion When state-of-the-art protocols are used, dipyridamole and dobutamine stress echocardiography have comparable and high diagnostic accuracy, similar to maximal post-exercise treadmill stress echocardiography. PMID:16672046

Comparison of exercise, dobutamine-atropine and dipyridamole-atropine stress echocardiography in detecting coronary artery disease.

PubMed

Nedeljkovic, Ivana; Ostojic, Miodrag; Beleslin, Branko; Djordjevic-Dikic, Ana; Stepanovic, Jelena; Nedeljkovic, Milan; Stojkovic, Sinisa; Stankovic, Goran; Saponjski, Jovica; Petrasinovic, Zorica; Giga, Vojislav; Mitrovic, Predrag

2006-05-03

Dipyridamole and dobutamine stress echocardiography testing are most widely utilized, but their sensitivity remained suboptimal in comparison to routine exercise stress echocardiography. The aim of our study is to compare, head-to-head, exercise, dobutamine and dipyridamole stress echocardiography tests, performed with state-of-the-art protocols in a large scale prospective group of patients. Dipyridamole-atropine (Dipatro: 0.84 mg/kg over 10 min i.v. dipyridamole with addition of up to 1 mg of atropine), dobutamine-atropine (Dobatro: up to 40 mcg/kg/min i.v. dobutamine with addition of up to 1 mg of atropine) and exercise (Ex, Bruce) were performed in 166 pts. Of them, 117 pts without resting wall motion abnormalities were enrolled in study (91 male; mean age 54 +/- 10 years; previous non-transmural myocardial infarction in 32 pts, angina pectoris in 69 pts and atypical chest pain in 16 pts). Tests were performed in random sequence, in 3 different days, within 5 day period under identical therapy. All patients underwent coronary angiography. Significant coronary artery disease (CAD; > or =50% diameter stenosis) was present in 69 pts (57 pts 1-vessel CAD, 12 multivessel CAD) and absent in 48 pts. Sensitivity (Sn) was 96%, 93% and 90%, whereas specificity (Sp) was 92%, 92% and 87% for Dobatro, Dipatro and Ex, respectively (p = ns). Concomitant beta blocker therapy did not influence peak rate-pressure product and Sn of Dobatro and Dipatro (p = ns). When state-of-the-art protocols are used, dipyridamole and dobutamine stress echocardiography have comparable and high diagnostic accuracy, similar to maximal post-exercise treadmill stress echocardiography.

Reduction of myocardial blood flow reserve in idiopathic dilated cardiomyopathy without overt heart failure and its relation with functional indices: an echo-Doppler and positron emission tomography study.

PubMed

Morales, Maria-Aurora; Neglia, Danilo; L'Abbate, Antonio

2008-08-01

Myocardial blood flow during pharmacological vasodilatation is depressed in patients with idiopathic dilated cardiomyopathy even the in absence of overt heart failure; the extent of myocardial blood flow abnormalities is not predictable by left ventricular ejection fraction (LVEF) and diastolic dimensions. To assess whether myocardial blood flow impairment in idiopathic dilated cardiomyopathy without overt heart failure can be related to Doppler-derived dP/dt and to echocardiographically determined left ventricular end systolic stress - which is linked to myocardial blood flow reserve in advanced disease. Twenty-six patients, New York Heart Association Class I-II, (LVEF 37.4 +/- 1.4%, left ventricular diastolic dimensions 62.6 +/- 0.9 mm) underwent resting/dipyridamole [13N]NH3 flow positron emission tomography and an ultrasonic study. Regional myocardial blood flow values (ml/min per g) were computed from positron emission tomography data in 13 left ventricular (LV) myocardial regions and averaged to provide mean myocardial blood flow and myocardial blood flow reserve, defined as dipyridamole/resting mean myocardial blood flow ratio. Resting myocardial blood flow was 0.686 +/- 0.045, dipyridamole myocardial blood flow 1.39 +/- 0.15 and myocardial blood flow reserve 2.12 +/- 0.2, lower than in controls (P < 0.01). The ratio dP/dt was directly related to dipyridamole myocardial blood flow and myocardial blood flow reserve (r = 0.552 and 0.703, P < 0.005 and P < 0.0001); no relation was found between myocardial blood flow and LVEF left ventricular diastolic dimensions, and left ventricular end systolic stress. In idiopathic dilated cardiomyopathy patients without overt heart failure, the extent of myocardial blood flow reserve impairment is related to dP/dt but not to more classical indices of left ventricular function.

Resting electrocardiogram and stress myocardial perfusion imaging in the determination of left ventricular systolic function: an assessment enhancing the performance of gated SPET.

PubMed

Moralidis, Efstratios; Spyridonidis, Tryfon; Arsos, Georgios; Skeberis, Vassilios; Anagnostopoulos, Constantinos; Gavrielidis, Stavros

2010-01-01

This study aimed to determine systolic dysfunction and estimate resting left ventricular ejection fraction (LVEF) from information collected during routine evaluation of patients with suspected or known coronary heart disease. This approach was then compared to gated single photon emission tomography (SPET). Patients having undergone stress (201)Tl myocardial perfusion imaging followed by equilibrium radionuclide angiography (ERNA) were separated into derivation (n=954) and validation (n=309) groups. Logistic regression analysis was used to develop scoring systems, containing clinical, electrocardiographic (ECG) and scintigraphic data, for the discrimination of an ERNA-LVEF<0.50. Linear regression analysis provided equations predicting ERNA-LVEF from those scores. In 373 patients LVEF was also assessed with (201)Tl gated SPET. Our results showed that an ECG-Scintigraphic scoring system was the best simple predictor of an ERNA-LVEF<0.50 in comparison to other models including ECG, clinical and scintigraphic variables in both the derivation and validation subpopulations. A simple linear equation was derived also for the assessment of resting LVEF from the ECG-Scintigraphic model. Equilibrium radionuclide angiography-LVEF had a good correlation with the ECG-Scintigraphic model LVEF (r=0.716, P=0.000), (201)Tl gated SPET LVEF (r=0.711, P=0.000) and the average LVEF from those assessments (r=0.796, P=0.000). The Bland-Altman statistic (mean+/-2SD) provided values of 0.001+/-0.176, 0.071+/-0.196 and 0.040+/-0.152, respectively. The average LVEF was a better discriminator of systolic dysfunction than gated SPET-LVEF in receiver operating characteristic (ROC) analysis and identified more patients (89%) with a myocardial perfusion imaging variables. This model provides reliable LVEF

Targeted Imaging of the Spatial and Temporal Variation of Matrix Metalloproteinase Activity in Porcine Model of Post-Infarct Remodeling: Relationship to Myocardial Dysfunction

PubMed Central

Sahul, Zakir H.; Mukherjee, Rupak; Song, James; McAteer, Jarod; Stroud, Robert E.; Dione, Donald P.; Staib, Lawrence; Papademetris, Xenophon; Dobrucki, Lawrence W.; Duncan, James S.; Spinale, Francis G.; Sinusas, Albert J.

2011-01-01

Background Matrix metalloproteinases (MMPs) are known to modulate left ventricular (LV) remodeling after a myocardial infarction (MI). However, the temporal and spatial variation of MMP activation and their relationship to mechanical dysfunction post MI remains undefined. Methods and Results MI was surgically induced in pigs (n=23) and cine MR and dual isotope hybrid SPECT/CT imaging obtained using thallium-201 (201Tl) and a technetium-99m labeled MMP targeted tracer (99mTc-RP805) at 1, 2 and 4 weeks post MI along with controls (n=5). Regional myocardial strain was computed from MR images and related to MMP zymography and ex vivo myocardial 99mTc-RP805 retention. MMP activation as assessed by in vivo and ex vivo 99mTc-RP805 imaging/retention studies was increased nearly 5-fold within the infarct region at 1 week post-MI and remained elevated up to 1 month post-MI. The post-MI change in LV end-diastolic volumes was correlated with MMP activity (y=31.34e0.48x, p=0.04). MMP activity was increased within the border and remote regions early post-MI, but declined over 1 month. There was a high concordance between regional 99mTc-RP805 uptake and ex vivo MMP-2 activity. Conclusions A novel, multimodality non-invasive hybrid SPECT/CT imaging approach was validated and applied for in vivo evaluation of MMP activation in combination with cine MR analysis of LV deformation. Increased 99mTc-RP805 retention was seen throughout the heart early post-MI and was not purely a reciprocal of 201Tl perfusion. 99mTc-RP805 SPECT/CT imaging may provide unique information regarding regional myocardial MMP activation and predict late post-MI LV remodeling. PMID:21505092

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.

Simultaneous dual-radionuclide myocardial perfusion imaging with a solid-state dedicated cardiac camera.

PubMed

Ben-Haim, Simona; Kacperski, Krzysztof; Hain, Sharon; Van Gramberg, Dean; Hutton, Brian F; Erlandsson, Kjell; Sharir, Tali; Roth, Nathaniel; Waddington, Wendy A; Berman, Daniel S; Ell, Peter J

2010-08-01

We compared simultaneous dual-radionuclide (DR) stress and rest myocardial perfusion imaging (MPI) with a novel solid-state cardiac camera and a conventional SPECT camera with separate stress and rest acquisitions. Of 27 consecutive patients recruited, 24 (64.5+/-11.8 years of age, 16 men) were injected with 74 MBq of (201)Tl (rest) and 250 MBq (99m)Tc-MIBI (stress). Conventional MPI acquisition times for stress and rest are 21 min and 16 min, respectively. Rest (201)Tl for 6 min and simultaneous DR 15-min list mode gated scans were performed on a D-SPECT cardiac scanner. In 11 patients DR D-SPECT was performed first and in 13 patients conventional stress (99m)Tc-MIBI SPECT imaging was performed followed by DR D-SPECT. The DR D-SPECT data were processed using a spill-over and scatter correction method. DR D-SPECT images were compared with rest (201)Tl D-SPECT and with conventional SPECT images by visual analysis employing the 17-segment model and a five-point scale (0 normal, 4 absent) to calculate the summed stress and rest scores. Image quality was assessed on a four-point scale (1 poor, 4 very good) and gut activity was assessed on a four-point scale (0 none, 3 high). Conventional MPI studies were abnormal at stress in 17 patients and at rest in 9 patients. In the 17 abnormal stress studies DR D-SPECT MPI showed 113 abnormal segments and conventional MPI showed 93 abnormal segments. In the nine abnormal rest studies DR D-SPECT showed 45 abnormal segments and conventional MPI showed 48 abnormal segments. The summed stress and rest scores on conventional SPECT and DR D-SPECT were highly correlated (r=0.9790 and 0.9694, respectively). The summed scores of rest (201)Tl D-SPECT and DR-DSPECT were also highly correlated (r=0.9968, p<0.0001 for all). In six patients stress perfusion defects were significantly larger on stress DR D-SPECT images, and five of these patients were imaged earlier by D-SPECT than by conventional SPECT. Fast and high-quality simultaneous DR

Diagnostic value of thallium-201 myocardial perfusion IQ-SPECT without and with computed tomography-based attenuation correction to predict clinically significant and insignificant fractional flow reserve

PubMed Central

Tanaka, Haruki; Takahashi, Teruyuki; Ohashi, Norihiko; Tanaka, Koichi; Okada, Takenori; Kihara, Yasuki

2017-01-01

Abstract The aim of this study was to clarify the predictive value of fractional flow reserve (FFR) determined by myocardial perfusion imaging (MPI) using thallium (Tl)-201 IQ-SPECT without and with computed tomography-based attenuation correction (CT-AC) for patients with stable coronary artery disease (CAD). We assessed 212 angiographically identified diseased vessels using adenosine-stress Tl-201 MPI-IQ-SPECT/CT in 84 consecutive, prospectively identified patients with stable CAD. We compared the FFR in 136 of the 212 diseased vessels using visual semiquantitative interpretations of corresponding territories on MPI-IQ-SPECT images without and with CT-AC. FFR inversely correlated most accurately with regional summed difference scores (rSDS) in images without and with CT-AC (r = −0.584 and r = −0.568, respectively, both P < .001). Receiver-operating characteristics analyses using rSDS revealed an optimal FFR cut-off of <0.80 without and with CT-AC. Although the diagnostic accuracy of FFR <0.80 did not significantly differ, FFR ≥0.82 was significantly more accurate with, than without CT-AC. Regions with rSDS ≥2 without or with CT-AC predicted FFR <0.80, and those with rSDS ≤1 without and with CT-AC predicted FFR ≥0.81, with 73% and 83% sensitivity, 84% and 67% specificity, and 79% and 75% accuracy, respectively. Although limited by the sample size and the single-center design, these findings showed that the IQ-SPECT system can predict FFR at an optimal cut-off of <0.80, and we propose a novel application of CT-AC to MPI-IQ-SPECT for predicting clinically significant and insignificant FFR even in nonobese patients. PMID:29390486

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Strydhorst, Jared H., E-mail: jared.strydhorst@gmail.com; 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 absolutemore » 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.« less

Reduced dose measurement of absolute myocardial blood flow using dynamic SPECT imaging in a porcine model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Timmins, Rachel; Klein, Ran; Petryk, Julia

Purpose: Absolute myocardial blood flow (MBF) and myocardial flow reserve (MFR) measurements provide important additional information over traditional relative perfusion imaging. Recent advances in camera technology have made this possible with single-photon emission tomography (SPECT). Low dose protocols are desirable to reduce the patient radiation risk; however, increased noise may reduce the accuracy of MBF measurements. The authors studied the effect of reducing dose on the accuracy of dynamic SPECT MBF measurements. Methods: Nineteen 30–40 kg pigs were injected with 370 + 1110 MBq of Tc-99m sestamibi or tetrofosmin or 37 + 111 MBq of Tl-201 at rest + stress.more » Microspheres were injected simultaneously to measure MBF. The pigs were imaged in list-mode for 11 min starting at the time of injection using a Discovery NM 530c camera (GE Healthcare). Each list file was modified so that 3/4, 1/2, 1/4, 1/8, 1/16, and 1/32 of the original counts were included in the projections. Modified projections were reconstructed with CT-based attenuation correction and an energy window-based scatter correction and analyzed with FlowQuant kinetic modeling software using a 1-compartment model. A modified Renkin-Crone extraction function was used to convert the tracer uptake rate K1 to MBF values. The SPECT results were compared to those from microspheres. Results: Correlation between SPECT and microsphere MBF values for the full injected activity was r ≥ 0.75 for all 3 tracers and did not significantly degrade over all count levels. The mean MBF and MFR and the standard errors in the estimates were not significantly worse than the full-count data at 1/4-counts (Tc99m-tracers) and 1/2-counts (Tl-201). Conclusions: Dynamic SPECT measurement of MBF and MFR in pigs can be performed with 1/4 (Tc99m-tracers) or 1/2 (Tl-201) of the standard injected activity without significantly reducing accuracy and precision.« less

Prognostic significance of normal quantitative Tl-201 stress scintigraphy in relation to pretest likelihood of coronary artery disease

DOE Office of Scientific and Technical Information (OSTI.GOV)

Russo, D.J.; Russo, D.; Clements, J.

A previous study reported an excellent prognosis and low cardiac event rate in patients(pts) with chest pain and normal quantitative T1-201 scintigraphy(SC). Such result would not be unexpected if the population under study had a predominance of pts with low pre-T1-201 likelihood(L) of significant coronary artery disease (CAD). Hence, the authors undertook telephone follow-up in pts with chest pain syndrome and normal quantitative T1-201 exercise SC, and related outcome to pretest L of CAD. Pretest L was determined by serial L analysis on the basis of: symptoms, age, sex, and exercise ECG. All pts had T1-201 SC immediately post exercisemore » and 2 hrs later. After interpolative background correction, circumferential count and washout profiles were generated. All pts had unequivocally normal studies. Of a total of 96 pts studied in 1981-82, 20 pts were lost to follow-up. Of the remaining 76 pts, 45 were males and 31 females. The pretest L of CAD had an inverted Gaussian distribution: thirty-four pts(47%) had <33% L of CAD, 3 pts (5%) had 33-66% L of CAD, and 35 pts(48%) had >66% L of CAD. Mean follow-up was 22+- 3 months. No deaths occurred. Two pts(3%) (with pretest L of 54% and 94%) had myocardial infarctions, 8 and 22 months respectively after T1-201 stress SC. One pt underwent percutaneous transluminal coronary angioplasty (PTCA) 16 months after T1-201 stress SC. These findings confirm excellent prognostic significance of normal quantitative T1-201 stress scintigraphy.« less

Dipyridamole and paracetamol overdose resulting in multi-organ failure.

PubMed

Cullis, P S; Watson, D; Cameron, A; McKee, R F

2013-08-01

Dipyridamole intoxication is rare and few reports exist amongst the current literature. A case of dipyridamole and paracetamol overdose is described in a previously healthy 58-year-old woman, which resulted in multi-organ failure requiring dialysis, inotropic support, ventilation and extensive surgical intervention for small bowel ischaemia. This case highlights the dangers of an unusually large overdose of a commonly prescribed drug, and reviews current knowledge of dipyridamole intoxication.

Thallium-201 for cardiac stress tests: residual radioactivity worries patients and security.

PubMed

Geraci, Matthew J; Brown, Norman; Murray, David

2012-12-01

A 47-year-old man presented to the Emergency Department (ED) in duress and stated he was "highly radioactive." There were no reports of nuclear disasters, spills, or mishaps in the local area. This report discusses the potential for thallium-201 (Tl-201) patients to activate passive radiation alarms days to weeks after nuclear stress tests, even while shielded inside industrial vehicles away from sensors. Characteristics of Tl-201, as used for medical imaging, are described. This patient was twice detained by Homeland Security Agents and searched after he activated radiation detectors at a seaport security checkpoint. Security agents deemed him not to be a threat, but they expressed concern regarding his health and level of personal radioactivity. The patient was subsequently barred from his job and sent to the hospital. Tl-201 is a widely used radioisotope for medical imaging. The radioactive half-life of Tl-201 is 73.1h, however, reported periods of extended personal radiation have been seen as far out as 61 days post-administration. This case describes an anxious, but otherwise asymptomatic patient presenting to the ED with detection of low-level personal radiation. Documentation should be provided to and carried by individuals receiving radionuclides for a minimum of five to six half-lives of the longest-lasting isotope provided. Patients receiving Tl-201 should understand the potential for security issues; reducing probable tense moments, confusion, and anxiety to themselves, their employers, security officials, and ED staff. Copyright © 2012 Elsevier Inc. All rights reserved.

Myocardial uptake and kinetic properties of technetium-99m-Q3 in dogs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gerson, M.C.; Millard, R.W.; McGoron, A.J.

1994-10-01

We postulated that {sup 99m}Tc-Q3, a cationic imaging agent, produces myocardial activity related to myocardial blood flow during myocardial ischemia and pharmacologic coronary artery vasodilation, and shows little or no myocardial redistribution over 4 hr after intravenous injection. In six Group 1 dogs, the chest was opened, the left circumflex coronary artery was acutely ligated, and dipyridamole (0.32, 0.56 or 0.84 mg/kg) was infused into the right atrium, followed by 10 mCi of {sup 99m}Tc-Q3. Myocardial blood flow was measured by radiolabeled microspheres. The animals were euthanized and 357 myocardial samples were assayed in a well counter for {sup 99m}Tcmore » activity. One week later, radiolabeled microsphere activity was counted and myocardial blood flow calculated. In nine Group 2 dogs, a variable occluder was placed around the left circumflex coronary artery and an ischemic level of circumflex blood flow was maintained constant over 4 hr as measured by an ultrasonic flow meter. Dipyridamole (0.56 mg/kg) was then infused into the right atrium followed by 10mCi of {sup 99m}Tc-Q3. Gamma camera images were acquired at 5, 15, 30, 60, 120 and 240 min following k{sup 99m}Tc-Q3 injection. Microsphere blood flow and endocardial biopsies (n - 6 dogs) were performed at 30, 60, 120 and 240 min following {sup 99m}TcQ3 injection. 31 refs., 9 figs., 1 tab.« less

[The development of a computer model in the quantitative assessment of thallium-201 myocardial scintigraphy].

PubMed

Raineri, M; Traina, M; Rotolo, A; Candela, B; Lombardo, R M; Raineri, A A

1993-05-01

Thallium-201 scintigraphy is a widely used noninvasive procedure for the detection and prognostic assessment of patients with suspected or proven coronary artery disease. Thallium uptake can be evaluated by a visual analysis or by a quantitative interpretation. Quantitative scintigraphy enhances disease detection in individual coronary arteries, provides a more precise estimate of the amount of ischemic myocardium, distinguishing scar from hypoperfused tissue. Due to the great deal of data, analysis, interpretation and comparison of thallium uptake can be very complex. We designed a computer-based system for the interpretation of quantitative thallium-201 scintigraphy data uptake. We used a database (DataEase 4.2-DataEase Italia). Our software has the following functions: data storage; calculation; conversion of numerical data into different definitions classifying myocardial perfusion; uptake data comparison; automatic conclusion; comparison of different scintigrams for the same patient. Our software is made up by 4 sections: numeric analysis, descriptive analysis, automatic conclusion, clinical remarks. We introduced in the computer system appropriate information, "logical paths", that use the "IF ... THEN" rules. The software executes these rules in order to analyze the myocardial regions in the 3 phases of scintigraphic analysis (stress, redistribution, re-injection), in the 3 projections (LAO 45 degrees, LAT,ANT), considering our uptake cutoff, obtaining, finally, the automatic conclusions. For these reasons, our computer-based system could be considered a real "expert system".

Comparison of americium-241 and technetium-99m as transmission sources for attenuation correction of thallium-201 SPECT imaging of the heart.

PubMed

Ficaro, E P; Fessler, J A; Rogers, W L; Schwaiger, M

1994-04-01

This study compares the ability of 241Am and 99mTc to estimate 201Tl attenuation maps while minimizing the loss in the precision of the emission data. A triple-head SPECT system with either an 241Am or 99mTc line source opposite a fan-beam collimator was used to estimate attenuation maps of the thorax of an anthropomorphic phantom. Linear attenuation values at 75 keV for 201Tl were obtained by linear extrapolation of the measured values from 241Am and 99mTc. Lung and soft-tissue estimates from both isotopes showed excellent agreement to within 3% of the measured values for 201Tl. Linear extrapolation did not yield satisfactory estimates for bone from either 241Am (+11.7%) or 99mTc (-15.3%). Patient data were used to estimate the dependence of crosstalk on patient size. Contamination from 201Tl in the transmission window was 5-6 times greater for 241Am compared to 99mTc, while the contamination in the 201Tl data in the transmission-emission detector head (head 1) was 4-5 times greater for 99mTc compared to 241Am. No contamination was detected in the 201Tl emission data of heads 2 and 3 from 241Am, whereas the 99mTc produced a small crosstalk component giving a signal-to-crosstalk ratio near 20:1. Measurements with a fillable chest phantom estimated the mean error introduced into the data from the removal of the crosstalk. Based on the measured data, 241Am is a suitable transmission source for simultaneous transmission-emission tomography for 201Tl cardiac studies.

Effect of dipyridamole plus aspirin on hemodialysis graft patency.

PubMed

Dixon, Bradley S; Beck, Gerald J; Vazquez, Miguel A; Greenberg, Arthur; Delmez, James A; Allon, Michael; Dember, Laura M; Himmelfarb, Jonathan; Gassman, Jennifer J; Greene, Tom; Radeva, Milena K; Davidson, Ingemar J; Ikizler, T Alp; Braden, Gregory L; Fenves, Andrew Z; Kaufman, James S; Cotton, James R; Martin, Kevin J; McNeil, James W; Rahman, Asif; Lawson, Jeffery H; Whiting, James F; Hu, Bo; Meyers, Catherine M; Kusek, John W; Feldman, Harold I

2009-05-21

Arteriovenous graft stenosis leading to thrombosis is a major cause of complications in patients undergoing hemodialysis. Procedural interventions may restore patency but are costly. Although there is no proven pharmacologic therapy, dipyridamole may be promising because of its known vascular antiproliferative activity. We conducted a randomized, double-blind, placebo-controlled trial of extended-release dipyridamole, at a dose of 200 mg, and aspirin, at a dose of 25 mg, given twice daily after the placement of a new arteriovenous graft until the primary outcome, loss of primary unassisted patency (i.e., patency without thrombosis or requirement for intervention), was reached. Secondary outcomes were cumulative graft failure and death. Primary and secondary outcomes were analyzed with the use of a Cox proportional-hazards regression with adjustment for prespecified covariates. At 13 centers in the United States, 649 patients were randomly assigned to receive dipyridamole plus aspirin (321 patients) or placebo (328 patients) over a period of 4.5 years, with 6 additional months of follow-up. The incidence of primary unassisted patency at 1 year was 23% (95% confidence interval [CI], 18 to 28) in the placebo group and 28% (95% CI, 23 to 34) in the dipyridamole-aspirin group, an absolute difference of 5 percentage points. Treatment with dipyridamole plus aspirin significantly prolonged the duration of primary unassisted patency (hazard ratio, 0.82; 95% CI, 0.68 to 0.98; P=0.03) and inhibited stenosis. The incidences of cumulative graft failure, death, the composite of graft failure or death, and serious adverse events (including bleeding) did not differ significantly between study groups. Treatment with dipyridamole plus aspirin had a significant but modest effect in reducing the risk of stenosis and improving the duration of primary unassisted patency of newly created grafts. (ClinicalTrials.gov number, NCT00067119.) 2009 Massachusetts Medical Society

Assessment of myocardial viability by dynamic tomographic iodine 123 iodophenylpentadecanoic acid imaging: comparison with rest-redistribution thallium 201 imaging.

PubMed

Iskandrian, A S; Powers, J; Cave, V; Wasserleben, V; Cassell, D; Heo, J

1995-01-01

This study examined the ability of dynamic 123I-labeled iodophenylpentadecanoic acid (IPPA) imaging to detect myocardial viability in patients with left ventricular (LV) dysfunction caused by coronary artery disease. Serial 180-degree single-photon emission computed tomographic (SPECT) images (five sets, 8 minutes each) were obtained starting 4 minutes after injection of 2 to 6 mCi 123I at rest in 21 patients with LV dysfunction (ejection fraction [EF] 34% +/- 11%). The segmental uptake was compared with that of rest-redistribution 201Tl images (20 segments/study). The number of perfusion defects (reversible and fixed) was similar by IPPA and thallium (11 +/- 5 vs 10 +/- 5 segments/patient; difference not significant). There was agreement between IPPA and thallium for presence or absence (kappa = 0.78 +/- 0.03) and nature (reversible, mild fixed, or severe fixed) of perfusion defects (kappa = 0.54 +/- 0.04). However, there were more reversible IPPA defects than reversible thallium defects (7 +/- 4 vs 3 +/- 4 segments/patient; p = 0.001). In 14 patients the EF (by gated pool imaging) improved after coronary revascularization from 33% +/- 11% to 39% +/- 12% (p = 0.002). The number of reversible IPPA defects was greater in the seven patients who had improvement in EF than in the patients without such improvement (10 +/- 4 vs 5 +/- 4 segments/patient; p = 0.075). 123I-labeled IPPA SPECT imaging is a promising new technique for assessment of viability. Reversible defects predict recovery of LV dysfunction after coronary revascularization.

Positron emission tomography for the assessment of myocardial viability: an evidence-based analysis.

PubMed

2010-01-01

myocardial viability. Intravenous contrast agents, which are high molecular weight inert gas microbubbles that act like red blood cells in the vascular space, can be used during echocardiography to assess myocardial viability. These agents allow for the assessment of myocardial blood flow (perfusion) and contractile function (as described above), as well as the simultaneous assessment of perfusion to make it possible to distinguish between stunned and hibernating myocardium. SPECT: SPECT can be performed using thallium-201 (Tl-201), a potassium analogue, or technetium-99 m labelled tracers. When Tl-201 is injected intravenously into a patient, it is taken up by the myocardial cells through regional perfusion, and Tl-201 is retained in the cell due to sodium/potassium ATPase pumps in the myocyte membrane. The stress-redistribution-reinjection protocol involves three sets of images. The first two image sets (taken immediately after stress and then three to four hours after stress) identify perfusion defects that may represent scar tissue or viable tissue that is severely hypoperfused. The third set of images is taken a few minutes after the re-injection of Tl-201 and after the second set of images is completed. These re-injection images identify viable tissue if the defects exhibit significant fill-in (> 10% increase in tracer uptake) on the re-injection images. The other common Tl-201 viability imaging protocol, rest-redistribution, involves SPECT imaging performed at rest five minutes after Tl-201 is injected and again three to four hours later. Viable tissue is identified if the delayed images exhibit significant fill-in of defects identified in the initial scans (> 10% increase in uptake) or if defects are fixed but the tracer activity is greater than 50%. There are two technetium-99 m tracers: sestamibi (MIBI) and tetrofosmin. The uptake and retention of these tracers is dependent on regional perfusion and the integrity of cellular membranes. Viability is assessed using

Myocardial perfusion SPECT 2015 in Germany. Results of the 7th survey.

PubMed

Lindner, Oliver; Burchert, Wolfgang; Schäfer, Wolfgang; Hacker, Marcus

2017-02-14

The working group Cardiovascular Nuclear Medicine of the German Society of Nuclear Medicine presents the results of the 7th survey of myocardial perfusion SPECT (MPS) of the reporting year 2015. 268 questionnaires (173 practices [PR], 67 hospitals [HO], 28 university hospitals [UH]) were evaluated. Results of the last survey from 2012 are set in squared brackets. MPS of 121 939 [105 941] patients were reported. 98 % [95 %] of all MPS were performed with Tc-99m radiopharmaceuticals and 2 % [5 %] with Tl-201. 78 % [79 %] of all patients were studied in PR, 14 % [15 %] in HO, and 8 % [6 %] in UH. A pharmacological stress test was performed in 43 % [39 %] (22 % [24 %] adenosine, 20 % [9 %] regadenoson, 1 % [6 %] dipyridamole or dobutamine). Attenuation correction was applied in 25 % [2009: 10 %] of MPS. Gated SPECT was performed in 78 % [70 %] of all rest MPS, in 80 % [73 %] of all stress and in 76 % [67 %] of all stress and rest MPS. 53 % [33 %] of all nuclear medicine departments performed MPS scoring by default, whereas 24 % [41 %] did not apply any quantification. 31 % [26 %] of all departments noticed an increase in their counted MPS and 29 % [29 %] no changes. Data from 89 departments which participated in all surveys showed an increase in MPS count of 11.1 % (PR: 12.2 %, HO: 4.8 %, UH: 18.4 %). 70 % [60 %] of the MPS were requested by ambulatory care cardiologists. The 2015 MPS survey reveals a high-grade adherence of routine MPS practice to current guidelines. The positive trend in MPS performance and number of MPS already observed in 2012 continues. Educational training remains necessary in the field of SPECT scoring.

Aspirin and Extended-Release Dipyridamole

MedlinePlus

The combination of aspirin and extended-release dipyridamole is in a class of drugs called antiplatelet agents. It works by preventing excessive blood clotting. It is used to reduce the risk of stroke in patients who have had or ...

Ocular Applications of Dipyridamole: A Review of Indications and Routes of Administration

PubMed Central

Isakov, Itzhak; Wlassoff, Wjatschesslaw; Ingram, April; Barishak, Y. Robert

2016-01-01

Abstract Dipyridamole was introduced decades ago as a treatment for angina, subsequently found to inhibit platelet aggregation. It is most commonly used, and approved for use in thromboembolism prevention, following surgery. Some of its recognized effects such as adenosine uptake inhibition, elevation of cAMP and cGMP levels, vasodilation, and tissue perfusion are important in various ocular disorders. For this reason, dipyridamole represents an interesting candidate as a therapeutic target for the treatment of eye disorders affecting different ocular structures. The aim of this article is to review the evidence and current understanding of the mechanisms by which dipyridamole exerts its effects on different ocular tissues, discuss the role of dipyridamole in clinical practice, and highlight areas of use and routes of administration. PMID:26696547

Roles of myocardial blood volume and flow in coronary artery disease: an experimental MRI study at rest and during hyperemia

PubMed Central

McCommis, Kyle S.; Goldstein, Thomas A.; Abendschein, Dana R.; Misselwitz, Bernd; Pilgram, Thomas; Gropler, Robert J.

2010-01-01

Objective To validate fast perfusion mapping techniques in a setting of coronary artery stenosis, and to further assess the relationship of absolute myocardial blood volume (MBV) and blood flow (MBF) to global myocardial oxygen demand. Methods A group of 27 mongrel dogs were divided into 10 controls and 17 with acute coronary stenosis. On 1.5-T MRI, first-pass perfusion imaging with a bolus injection of a blood-pool contrast agent was performed to determine myocardial perfusion both at rest and during either dipyridamole-induced vasodilation or dobutamine-induced stress. Regional values of MBF and MBV were quantified by using a fast mapping technique. Color microspheres and 99mTc-labeled red blood cells were injected to obtain respective gold standards. Results Microsphere-measured MBF and 99mTc-measured MBV reference values correlated well with the MR results. Given the same changes in MBF, changes in MBV are twofold greater with dobutamine than with dipyridamole. Under dobutamine stress, MBV shows better association with total myocardial oxygen demand than MBF. Coronary stenosis progressively reduced this association in the presence of increased stenosis severity. Conclusions MR first-pass perfusion can rapidly estimate regional MBF and MBV. Absolute quantification of MBV may add additional information on stenosis severity and myocardial viability compared with standard qualitative clinical evaluations of myocardial perfusion. PMID:20182731

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.

Cardiac involvement in facio-scapulo-humeral muscular dystrophy: a family study using Thallium-201 single-photon-emission-computed tomography.

PubMed

Faustmann, P M; Farahati, J; Rupilius, B; Dux, R; Koch, M C; Reiners, C

1996-12-01

Fifteen persons from two consecutive generations of one family affected with facio-scapulo-humeral muscular dystrophy (FSHD) were clinically and neurophysiologically examined. Diagnostic muscle biopsies were obtained from two members. Linkage analysis showed that all four affected members of the family inherit the same 4q35 haplotype giving a lod score of z = +1.44. Six family members were examined by ECG at rest and under stress, by two-dimensional echocardiography, and by cardiac Thallium-201 single-photon-emission computed tomography (Tl-201-SPECT) under dobutamine stress and at rest. Abnormal reduced Tl-201 uptake in cardiac SPECT was only found in the affected members of the family. Therefore we suggest that cardiac Tl-201-SPECT abnormalities in FSHD reflect cardiomyogenic changes in this type of muscular disease.

Association between aortic valve calcification and myocardial ischemia, especially in asymptomatic patients.

PubMed

Yamazato, Ryo; Yamamoto, Hideya; Tadehara, Futoshi; Teragawa, Hiroki; Kurisu, Satoshi; Dohi, Yoshihiro; Ishibashi, Ken; Kunita, Eiji; Utsunomiya, Hiroto; Oka, Toshiharu; Kihara, Yasuki

2012-08-01

Aortic valve calcification (AVC) is recognized as a manifestation of systemic arteriosclerosis. However, it is unclear whether AVC is associated with myocardial ischemia. Stress myocardial perfusion SPECT (MPS) is widely used for the diagnosis of myocardial ischemia. However, routine MPS is not recommended, particularly in asymptomatic patients. Accordingly, we investigated the hypothesis that the presence of AVC is strongly associated with inducible myocardial ischemia, even among asymptomatic patients. We investigated 669 consecutive patients who underwent both adenosine stress (201)Tl MPS and echocardiography. We evaluated the extent and severity of myocardial ischemia by the summed difference score (SDS). We defined the presence of myocardial ischemia as SDS ≥ 3 and moderate to severe ischemia as SDS ≥ 8. We classified the severity of AVC according to the number of affected aortic leaflets. We also compared the mean SDS and the prevalence of SDS ≥ 3 and SDS ≥ 8 among patients stratified by the severity of AVC. The presence of AVC was significantly associated with myocardial ischemia (odds ratio [OR], 1.56; 95% confidence interval [CI], 1.10-2.23; P = 0.013) and moderate to severe ischemia (OR, 2.16; 95% CI, 1.26-3.80; P = 0.0061). In 311 asymptomatic patients, AVC was strongly associated with moderate to severe ischemia (OR, 4.31; 95% CI, 1.67-12.8; P = 0.0043). However, the SDS value and the prevalence of SDS ≥ 3 and SDS ≥ 8 did not increase with increasing number of affected aortic leaflets. The presence of AVC may be associated with the presence of myocardial ischemia, particularly in asymptomatic patients. However, we found no association between the extent of AVC and inducible myocardial ischemia. The presence of AVC may be a useful anatomic marker to help identify patients at high risk of myocardial ischemia, particularly asymptomatic patients.

Routine Clinical Quantitative Rest Stress Myocardial Perfusion for Managing Coronary Artery Disease: Clinical Relevance of Test-Retest Variability.

PubMed

Kitkungvan, Danai; Johnson, Nils P; Roby, Amanda E; Patel, Monika B; Kirkeeide, Richard; Gould, K Lance

2017-05-01

Positron emission tomography (PET) quantifies stress myocardial perfusion (in cc/min/g) and coronary flow reserve to guide noninvasively the management of coronary artery disease. This study determined their test-retest precision within minutes and daily biological variability essential for bounding clinical decision-making or risk stratification based on low flow ischemic thresholds or follow-up changes. Randomized trials of fractional flow reserve-guided percutaneous coronary interventions established an objective, quantitative, outcomes-driven standard of physiological stenosis severity. However, pressure-derived fractional flow reserve requires invasive coronary angiogram and was originally validated by comparison to noninvasive PET. The time course and test-retest precision of serial quantitative rest-rest and stress-stress global myocardial perfusion by PET within minutes and days apart in the same patient were compared in 120 volunteers undergoing serial 708 quantitative PET perfusion scans using rubidium 82 (Rb-82) and dipyridamole stress with a 2-dimensional PET-computed tomography scanner (GE DST 16) and University of Texas HeartSee software with our validated perfusion model. Test-retest methodological precision (coefficient of variance) for serial quantitative global myocardial perfusion minutes apart is ±10% (mean ΔSD at rest ±0.09, at stress ±0.23 cc/min/g) and for days apart is ±21% (mean ΔSD at rest ±0.2, at stress ±0.46 cc/min/g) reflecting added biological variability. Global myocardial perfusion at 8 min after 4-min dipyridamole infusion is 10% higher than at standard 4 min after dipyridamole. Test-retest methodological precision of global PET myocardial perfusion by serial rest or stress PET minutes apart is ±10%. Day-to-different-day biological plus methodological variability is ±21%, thereby establishing boundaries of variability on physiological severity to guide or follow coronary artery disease management. Maximum stress

Effect of Dipyridamole plus Aspirin on Hemodialysis Graft Patency

PubMed Central

Dixon, Bradley S.; Beck, Gerald J.; Vazquez, Miguel A.; Greenberg, Arthur; Delmez, James A.; Allon, Michael; Dember, Laura M.; Himmelfarb, Jonathan; Gassman, Jennifer J.; Greene, Tom; Radeva, Milena K.; Davidson, Ingemar J.; Ikizler, T. Alp; Braden, Gregory L.; Fenves, Andrew Z.; Kaufman, James S.; Cotton, James R.; Martin, Kevin J.; McNeil, James W.; Rahman, Asif; Lawson, Jeffery H.; Whiting, James F.; Hu, Bo; Meyers, Catherine M.; Kusek, John W.; Feldman, Harold I.

2014-01-01

BACKGROUND Arteriovenous graft stenosis leading to thrombosis is a major cause of complications in patients undergoing hemodialysis. Procedural interventions may restore patency but are costly. Although there is no proven pharmacologic therapy, dipyridamole may be promising because of its known vascular antiproliferative activity. METHODS We conducted a randomized, double-blind, placebo-controlled trial of extended-release dipyridamole, at a dose of 200 mg, and aspirin, at a dose of 25 mg, given twice daily after the placement of a new arteriovenous graft until the primary outcome, loss of primary unassisted patency (i.e., patency without thrombosis or requirement for intervention), was reached. Secondary outcomes were cumulative graft failure and death. Primary and secondary outcomes were analyzed with the use of a Cox proportional-hazards regression with adjustment for prespecified covariates. RESULTS At 13 centers in the United States, 649 patients were randomly assigned to receive dipyridamole plus aspirin (321 patients) or placebo (328 patients) over a period of 4.5 years, with 6 additional months of follow-up. The incidence of primary unassisted patency at 1 year was 23% (95% confidence interval [CI], 18 to 28) in the placebo group and 28% (95% CI, 23 to 34) in the dipyridamole–aspirin group, an absolute difference of 5 percentage points. Treatment with dipyridamole plus aspirin significantly prolonged the duration of primary unassisted patency (hazard ratio, 0.82; 95% CI, 0.68 to 0.98; P = 0.03) and inhibited stenosis. The incidences of cumulative graft failure, death, the composite of graft failure or death, and serious adverse events (including bleeding) did not differ significantly between study groups. CONCLUSIONS Treatment with dipyridamole plus aspirin had a significant but modest effect in reducing the risk of stenosis and improving the duration of primary unassisted patency of newly created grafts. (ClinicalTrials.gov number, NCT00067119.) PMID

Myocardial perfusion and left ventricular function indices assessed by gated myocardial perfusion SPECT in methamphetamine abusers.

PubMed

Dadpour, Bita; Dabbagh Kakhki, Vahid R; Afshari, Reza; Dorri-Giv, Masoumeh; Mohajeri, Seyed A R; Ghahremani, Somayeh

2016-12-01

Methamphetamine (MA) is associated with alterations of cardiac structure and function, although it is less known. In this study, we assessed possible abnormality in myocardial perfusion and left ventricular function using gated myocardial perfusion SPECT. Fifteen patients with MA abuse, on the basis of Diagnostic and Statistical Manual of Mental Disorders, 4th ed. (DSM-IV) MA dependency determined by Structured Clinical Interview for DSM-IV, underwent 2-day dipyridamole stress/rest Tc-sestamibi gated myocardial perfusion SPECT. An average daily dose of MA use was 0.91±1.1 (0.2-4) g. The duration of MA use was 3.4±2.1 (1-7) years. In visual and semiquantitative analyses, all patients had normal gated myocardial perfusion SPECT, with no perfusion defects. In all gated SPECT images, there was no abnormality in left ventricular wall motion and thickening. All summed stress scores and summed rest scores were below 3. Calculated left ventricular functional indices including the end-diastolic volume, end-systolic volume, and left ventricular ejection fraction were normal. Many cardiac findings because of MA mentioned in previous reports are less likely because of significant epicardial coronary artery stenosis.

Papillary carcinoma in ectopic thyroid detected by Tl-201 scintigraphy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Michigishi, T.; Mizukami, Y.; Mura, T.

1991-05-01

A 37-year-old man with papillary carcinoma in an ectopic thyroid is presented. Excisional biopsy revealed the cervical mass to be a metastasis from thyroid cancer. X-ray, ultrasonography, and computed tomography, however, failed to identify the primary tumor in the thyroid. Incidental TI-201 uptake was noted in the midline of the anterior neck, and a palpable nodule was discovered in this area. Fine needle aspiration cytology demonstrated Class V papillary adenocarcinoma, and subsequent surgery confirmed a papillary carcinoma in the ectopic thyroid. This case suggests the usefulness of TI-201 scintigraphy for the detection of ectopic thyroid malignancy.

Clinical results with beta-methyl-p-(123I)iodophenylpentadecanoic acid, single-photon emission computed tomography in cardiac disease.

PubMed

Nishimura, T; Uehara, T; Shimonagata, T; Nagata, S; Haze, K

1994-01-01

This study was undertaken to evaluate the relationships, between myocardial perfusion and metabolism. Simultaneous beta-methyl-p(123I)iodophenylpentadecanoic acid (123I-BMIPP) and thallium 201 myocardial single-photon emission computed tomography (SPECT) were performed in 25 patients with myocardial infarction (group A) and 16 patients with hypertrophic cardiomyopathy (group B). The severity scores of 123I-BMIPP and 201Tl myocardial SPECT images were evaluated semiquantitatively by segmental analysis. In Group A, dissociations between thallium- and 123I-BMIPP-imaged defects were frequently observed in patients with successful reperfusion compared with those with no reperfusion and those with reinfarction. In four patients with successful reperfusion, repeated 123I-BMIPP and 201Tl myocardial SPECT showed gradual improvement of the 123I-BMIPP severity score compared with the thallium severity score. In group B, dissociations between thallium- and 123I-BMIPP-imaged defects were also demonstrated in hypertrophic myocardium. In addition, nonhypertrophic myocardium also had decreased 123I-BMIPP uptake. In groups A and B, 123I-BMIPP severity scores correlated well with left ventricular function compared with thallium severity scores. These findings indicate that 123I-BMIPP is a suitable agent for the assessment of functional integrity, because left ventricular wall motion is energy dependent and 123I-BMIPP may reflect an aspect of myocardial energy production. This agent may be useful for the early detection and patient management of various heart diseases as an alternative to positron emission tomographic study.

Magnetic resonance imaging (MRI) for the assessment of myocardial viability: an evidence-based analysis.

PubMed

2010-01-01

diagnostic accuracy of echocardiographic assessment of myocardial viability. Intravenous contrast agents, which are high molecular weight inert gas microbubbles that act like red blood cells in the vascular space, can be used during echocardiography to assess myocardial viability. These agents allow for the assessment of myocardial blood flow (perfusion) and contractile function (as described above), as well as the simultaneous assessment of perfusion to make it possible to distinguish between stunned and hibernating myocardium. SPECT: SPECT can be performed using thallium-201 (Tl-201), a potassium analogue, or technetium-99 m labelled tracers. When Tl-201 is injected intravenously into a patient, it is taken up by the myocardial cells through regional perfusion, and Tl-201 is retained in the cell due to sodium/potassium ATPase pumps in the myocyte membrane. The stress-redistribution-reinjection protocol involves three sets of images. The first two image sets (taken immediately after stress and then three to four hours after stress) identify perfusion defects that may represent scar tissue or viable tissue that is severely hypoperfused. The third set of images is taken a few minutes after the re-injection of Tl-201 and after the second set of images is completed. These re-injection images identify viable tissue if the defects exhibit significant fill-in (> 10% increase in tracer uptake) on the re-injection images. The other common Tl-201 viability imaging protocol, rest-redistribution, involves SPECT imaging performed at rest five minutes after Tl-201 is injected and again three to four hours later. Viable tissue is identified if the delayed images exhibit significant fill-in of defects identified in the initial scans (> 10% increase in uptake) or if defects are fixed but the tracer activity is greater than 50%. There are two technetium-99 m tracers: sestamibi (MIBI) and tetrofosmin. The uptake and retention of these tracers is dependent on regional perfusion and the

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shanes, J.G.; Krone, R.J.; Fisher, K.

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%.more » 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.« less

Aspirin and extended-release dipyridamole versus clopidogrel for recurrent stroke.

PubMed

Sacco, Ralph L; Diener, Hans-Christoph; Yusuf, Salim; Cotton, Daniel; Ounpuu, Stephanie; Lawton, William A; Palesch, Yuko; Martin, Reneé H; Albers, Gregory W; Bath, Philip; Bornstein, Natan; Chan, Bernard P L; Chen, Sien-Tsong; Cunha, Luis; Dahlöf, Björn; De Keyser, Jacques; Donnan, Geoffrey A; Estol, Conrado; Gorelick, Philip; Gu, Vivian; Hermansson, Karin; Hilbrich, Lutz; Kaste, Markku; Lu, Chuanzhen; Machnig, Thomas; Pais, Prem; Roberts, Robin; Skvortsova, Veronika; Teal, Philip; Toni, Danilo; Vandermaelen, Cam; Voigt, Thor; Weber, Michael; Yoon, Byung-Woo

2008-09-18

Recurrent stroke is a frequent, disabling event after ischemic stroke. This study compared the efficacy and safety of two antiplatelet regimens--aspirin plus extended-release dipyridamole (ASA-ERDP) versus clopidogrel. In this double-blind, 2-by-2 factorial trial, we randomly assigned patients to receive 25 mg of aspirin plus 200 mg of extended-release dipyridamole twice daily or to receive 75 mg of clopidogrel daily. The primary outcome was first recurrence of stroke. The secondary outcome was a composite of stroke, myocardial infarction, or death from vascular causes. Sequential statistical testing of noninferiority (margin of 1.075), followed by superiority testing, was planned. A total of 20,332 patients were followed for a mean of 2.5 years. Recurrent stroke occurred in 916 patients (9.0%) receiving ASA-ERDP and in 898 patients (8.8%) receiving clopidogrel (hazard ratio, 1.01; 95% confidence interval [CI], 0.92 to 1.11). The secondary outcome occurred in 1333 patients (13.1%) in each group (hazard ratio for ASA-ERDP, 0.99; 95% CI, 0.92 to 1.07). There were more major hemorrhagic events among ASA-ERDP recipients (419 [4.1%]) than among clopidogrel recipients (365 [3.6%]) (hazard ratio, 1.15; 95% CI, 1.00 to 1.32), including intracranial hemorrhage (hazard ratio, 1.42; 95% CI, 1.11 to 1.83). The net risk of recurrent stroke or major hemorrhagic event was similar in the two groups (1194 ASA-ERDP recipients [11.7%], vs. 1156 clopidogrel recipients [11.4%]; hazard ratio, 1.03; 95% CI, 0.95 to 1.11). The trial did not meet the predefined criteria for noninferiority but showed similar rates of recurrent stroke with ASA-ERDP and with clopidogrel. There is no evidence that either of the two treatments was superior to the other in the prevention of recurrent stroke. (ClinicalTrials.gov number, NCT00153062.) 2008 Massachusetts Medical Society

Comparison of personnel radiation dosimetry from myocardial perfusion scintigraphy: Technetium-99m-sestamibi versus thallium-201

DOE Office of Scientific and Technical Information (OSTI.GOV)

Culver, C.M.; Dworkin, H.J.

1993-07-01

The whole-body and hand radiation doses to our technical staff were retrospectively compared for three distinct 4-mo periods when either 201TI or 99mTc-sestamibi were exclusively used for stress myocardial perfusion imaging. During the initial 4-mo period when 99mTc-sestamibi replaced 201TI, the mean whole-body film badge readings increased from 100 to 450 microSv/mo (p < 0.001) for nuclear medicine technologists (n = 10) and from 240 to 560 microSv/mo (p < 0.05) for radiopharmacy technologists (n = 2). Mean TLD readings to the hands also increased, although the differences were not statistically significant for the nuclear medicine technologists. Noninvasive cardiology staffmore » were monitored with film badges and the mean whole-body film badge reading, when 99mTc-sestamibi was the imaging agent, was 360 microSv per month. Radiation reduction methods that decreased radiation exposure to staff were utilized. The most effective included the use of a lead face shield and lead lined storage container in the noninvasive imaging area, handling spills by shielding instead of decontamination and methods to reduce time spent in close proximity to the patient.« less

Patient- and clinician-reported satisfaction with pharmacological stress agents for single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI).

PubMed

Hudgens, Stacie; Breeze, Janis; Spalding, James

2013-01-01

The objective of this study was to compare clinician and patient measures of satisfaction with two pharmacological stress agents (PSA), regadenoson and dipyridamole, used in Single Photon Emission Computed Tomography (SPECT) Myocardial Perfusion Imaging (MPI). This observational study included patients who had undergone SPECT MPI with regadenoson or dipyridamole, as well as the clinician/clinical technologist who performed the test. Mean scores for individual item and domain scores of the main outcome measures were computed as well as the effect sizes (ES) of the mean difference in scores between treatment groups. Statistical significance of the mean item and domain score differences were assessed via Mann-Whitney tests. Two self-report questionnaires which had beeb previously developed and validated: Patient Satisfaction/Preference Questionnaire (PSPQ) and Clinician Satisfaction/Preference Questionnaire (CSPQ). A total of 87 patients (68 received regadenoson, 19 received dipyridamole) and nine clinicians/clinical technologists took part in the study. Patients had a mean age of 66.8 ± 12.2 years, and 56.3% were male. Compared to dipyridamole, use of regadenoson was associated with greater clinician satisfaction on all items and domains of the CSPQ (p < 0.001 for all comparisons). Among patients, regadenoson was associated with less bother and greater satisfaction than dipyridamole for all items on the PSPQ. These patients reported less stinging at the injection site (ES = -0.66) and less nervousness during injection (ES = -0.60). The PSPQ found that regadenoson patients were more satisfied with their PSA than dipyridamole patients in all areas. This study utilized a relatively small sample size of dipyridamole patients and lacked an adenosine group. A broader sampling of professionals would also help demonstrate generalizability. Both patients and clinicians reported higher satisfaction with regadenoson compared to dipyridamole for SPECT-MPI. Clinicians were

Myocardial scintigraphy using a fatty acid analogue detects coronary artery disease in hemodialysis patients.

PubMed

Nishimura, Masato; Hashimoto, Tetsuya; Kobayashi, Hiroyuki; Fukuda, Toyofumi; Okino, Koji; Yamamoto, Noriyuki; Fujita, Hiroshi; Inoue Tsunehiko Nishimura, Naoto; Ono, Toshihiko

2004-08-01

Coronary artery disease contributes significantly to mortality in end-stage renal disease (ESRD) patients. Single-photon emission computed tomography (SPECT) using an iodinated fatty acid analogue, iodine-123-methyl iodophenylpentadecanoic acid (123I-BMIPP), can assess fatty acid metabolism in the myocardium. We investigated the ability of 123I-BMIPP SPECT to detect coronary artery disease in hemodialysis patients compared with 201thallium chloride (201Tl) SPECT. We prospectively studied 130 ESRD patients undergoing hemodialysis for a mean of 88.6 months (male/female, 77/53; mean age, 63.8 years). Dual SPECT using 123I-BMIPP and 201Tl was performed, followed by coronary angiography. SPECT findings were graded in 17 segments on a five-point scale (0, normal uptake; 4, none) and assessed as a summed score. By coronary angiography, 71.5% of patients (93/130) had significant coronary stenosis (> or =75%), and five patients showed coronary spasm without coronary stenosis. When a BMIPP summed score of 6 or more was defined as abnormal, sensitivity, specificity, and accuracy for detecting coronary artery disease by BMIPP SPECT were 98.0%, 65.6%, and 90.0%, respectively; in contrast, these parameters for detecting coronary artery disease by Tl SPECT were 84.7%, 46.9%, and 75.0%, respectively, when a Tl summed score of 1 or more was defined as abnormal. In receiver operating characteristic analysis, the area under the curve was 0.895 in BMIPP and 0.727 in Tl SPECT, respectively. Resting BMIPP SPECT is superior to Tl SPECT for detecting coronary lesions, and provides safe screening for coronary artery disease among maintenance hemodialysis patients.

Comparison between fragmented QRS and Q waves in myocardial scar detection using myocardial perfusion single photon emission computed tomography.

PubMed

Dabbagh Kakhki, Vahid Reza; Ayati, Narjess; Zakavi, Seyed Rasoul; Sadeghi, Ramin; Tayyebi, Mohammad; Shariati, Farzaneh

2015-01-01

Accurate diagnosis of myocardial infarction (MI) is of paramount importance in patient management, which necessitates the development of efficient and accurate diagnostic methods. Q wave is not present in all patients with MI, and its prevalence is declining. Recently, fragmented QRS (fQRS) complex has been introduced as a marker of prior MI. To investigate diagnostic value of fQRS compared to Q wave. We included 500 consecutive patients with known or suspected coronary artery disease who underwent two days of gated myocardial perfusion imaging using dipyridamole pharmacologic stress. Electrocardiogram (ECG) was evaluated to detect fQRS as well as Q-wave. Finally, subjects were compared in terms of ventricular perfusion and function indices. A total of 207 men and 269 women with mean age of 57.06 ± 12 years were studied. ECG analysis showed that 14.3% of the patients had both fQRS and Q waves, 30.7% had fQRS, and 3.8% had Q waves. Fixed myocardial perfusion defect was noted in 22.3% of patients according to MPIs. Sensitivity, specificity, and positive and negative predictive values for myocardial scar detection were 78%, 65%, 39%, and 91%, respectively, for fQRS and 61%, 94%, 76%, and 89%, respectively, for Q wave. Although fQRS had lower specificity compared to Q wave in the detection of myocardial scar, due to higher sensitivity and negative predictive value can be an invaluable diagnostic index. There is also an incremental value for fQRS in association with Q-wave in myocardial scar assessment.

Nuclear cardiology. I - Radionuclide angiographic assessment of left ventricular contraction: uses, limitations and future directions. II - The role of myocardial perfusion imaging using thallium-201 in diagnosis of coronary heart disease

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bodenheimer, M.M.; Banka, V.S.; Helfant, R.H.

1980-01-01

The current status of radionuclide angiography is reviewed. First pass and gated equilibrium methods for determining left ventricular contraction are compared. Some clinical applications of radionuclide angiography are then examined, including the detection of discrete versus diffuse asynergy and the assessment of myocardial infarction. The second part of this work reviews the uses and limitations of thallium-201 perfusion imaging in the diagnosis of the acute and chronic manifestations of coronary heart disease. Theoretical and technical considerations of thallium-201 imaging are reviewed along with the clinical implications of the technique.

Production of high purity radiothallium

DOEpatents

Lebowitz, Elliot; Greene, Margaret W.

1976-11-23

The method of producing high purity thallium-201 for use as a myocardial scanning agent comprising the steps of irradiating a thallium target with protons to give the reaction .sup.203 Tl(p,3n) .sup.201.sub.Pb, separating in ion exchange columns the lead from the thallium isotopes, permitting the lead to decay, and then purifying the thallium solution and converting the thallium present to thallous form in which it can be used.

Spontaneous Tl(I)-to-Tl(III) oxidation in dynamic heterobimetallic Hg(II)/Tl(I) porphyrin complexes.

PubMed

Ndoyom, Victoria; Fusaro, Luca; Roisnel, Thierry; Le Gac, Stéphane; Boitrel, Bernard

2016-01-11

Strapped heterobimetallic Hg(II)/Tl(I) porphyrin complexes, with both metal ions bridged by the N-core in a dynamic way, undergo spontaneous Tl(I)-to-Tl(III) oxidation leading to a mono-Tl(III) complex and a mixed valence Tl(I)/Tl(III) bimetallic complex. It provides a new opportunity to tune metal ion translocations in bimetallic porphyrin systems.

Magnetic Resonance Imaging (MRI) for the Assessment of Myocardial Viability

PubMed Central

2010-01-01

techniques including echocardiography using contrast agents, harmonic imaging, and power doppler imaging may help to improve the diagnostic accuracy of echocardiographic assessment of myocardial viability. Stress Echocardiography with Contrast Intravenous contrast agents, which are high molecular weight inert gas microbubbles that act like red blood cells in the vascular space, can be used during echocardiography to assess myocardial viability. These agents allow for the assessment of myocardial blood flow (perfusion) and contractile function (as described above), as well as the simultaneous assessment of perfusion to make it possible to distinguish between stunned and hibernating myocardium. SPECT SPECT can be performed using thallium-201 (Tl-201), a potassium analogue, or technetium-99 m labelled tracers. When Tl-201 is injected intravenously into a patient, it is taken up by the myocardial cells through regional perfusion, and Tl-201 is retained in the cell due to sodium/potassium ATPase pumps in the myocyte membrane. The stress-redistribution-reinjection protocol involves three sets of images. The first two image sets (taken immediately after stress and then three to four hours after stress) identify perfusion defects that may represent scar tissue or viable tissue that is severely hypoperfused. The third set of images is taken a few minutes after the re-injection of Tl-201 and after the second set of images is completed. These re-injection images identify viable tissue if the defects exhibit significant fill-in (> 10% increase in tracer uptake) on the re-injection images. The other common Tl-201 viability imaging protocol, rest-redistribution, involves SPECT imaging performed at rest five minutes after Tl-201 is injected and again three to four hours later. Viable tissue is identified if the delayed images exhibit significant fill-in of defects identified in the initial scans (> 10% increase in uptake) or if defects are fixed but the tracer activity is greater than 50

Myocardial perfusion imaging with technetium-99m SQ30217: Comparison with thallium-201 and coronary anatomy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seldin, D.W.; Johnson, L.L.; Blood, D.K.

1989-03-01

Myocardial perfusion in ten normal volunteers and 20 patients with coronary artery disease documented by recent coronary arteriography was studied with 99mTc-labeled SQ30217 and /sup 201/TI. Plantar /sup 201/TI imaging followed standard treadmill exercise and planar SQ30217 imaging followed upright bicycle exercise, performed to angina, or the same double product achieved on the treadmill test. Upright anterior, 30 degrees left anterior oblique, and 60 degrees left anterior oblique images were obtained for 3, 6, and 9 min, respectively, starting 2 min after injection of 15 mCi of 99mTc SQ30217. A second 15-mCi dose was injected at rest approximately 2 hrmore » later, and the same imaging protocol was followed. No adverse reactions or laboratory abnormalities attributable to SQ30217 were observed. All scans on the normal volunteers were interpreted as normal. Qualitative readings of both tests were equally sensitive for detecting patients with coronary disease (SQ30217 - 16/20, TI - 17/20, p = NS) and identifying abnormal vessels (SQ30217 - 19/45, TI - 21/45, p = NS). Both agents were falsely positive in 1/15 vessels. Ten vascular regions showed persistent abnormalities on resting SQ30217 scans; eight of these were distal to stenoses of at least 90% and three were also abnormal on thallium redistribution images. Hepatic uptake of SQ30217 obscured inferoapical segments in some views in 14/20 patients but did not interfere with abnormal vessel identification.« less

Hyperemic stress myocardial perfusion cardiovascular magnetic resonance in mice at 3 Tesla: initial experience and validation against microspheres.

PubMed

Jogiya, Roy; Makowski, Markus; Phinikaridou, Alkystsis; Patel, Ashish S; Jansen, Christian; Zarinabad, Niloufar; Chiribiri, Amedeo; Botnar, Rene; Nagel, Eike; Kozerke, Sebastian; Plein, Sven

2013-07-21

Dynamic first pass contrast-enhanced myocardial perfusion is the standard CMR method for the estimation of myocardial blood flow (MBF) and MBF reserve in man, but it is challenging in rodents because of the high temporal and spatial resolution requirements. Hyperemic first pass myocardial perfusion CMR during vasodilator stress in mice has not been reported. Five C57BL/6 J mice were scanned on a clinical 3.0 Tesla Achieva system (Philips Healthcare, Netherlands). Vasodilator stress was induced via a tail vein catheter with an injection of dipyridamole. Dynamic contrast-enhanced perfusion imaging (Gadobutrol 0.1 mmol/kg) was based on a saturation recovery spoiled gradient echo method with 10-fold k-space and time domain undersampling (k-t PCA). One week later the mice underwent repeat anaesthesia and LV injections of fluorescent microspheres at rest and at stress. Microspheres were analysed using confocal microscopy and fluorescence-activated cell sorting. Mean MBF at rest measured by Fermi-function constrained deconvolution was 4.1 ± 0.5 ml/g/min and increased to 9.6 ± 2.5 ml/g/min during dipyridamole stress (P = 0.005). The myocardial perfusion reserve was 2.4 ± 0.54. The mean count ratio of stress to rest microspheres was 2.4 ± 0.51 using confocal microscopy and 2.6 ± 0.46 using fluorescence. There was good agreement between cardiovascular magnetic resonance CMR and microspheres with no significant difference (P = 0.84). First-pass myocardial stress perfusion CMR in a mouse model is feasible at 3 Tesla. Rest and stress MBF values were consistent with existing literature and perfusion reserve correlated closely to microsphere analysis. Data were acquired on a 3 Tesla scanner using an approach similar to clinical acquisition protocols, potentially facilitating translation of imaging findings between rodent and human studies.

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

False-positive defects on exercise 99mTc-sestamibi SPECT imaging, but not on dipyridamole 99mTc-sestamibi SPECT imaging, in a patient with right bundle branch block (RBBB).

PubMed

Javadi, Hamid; Jallalat, Sara; Semnani, Shahriar; Mogharrabi, Mehdi; Nabipour, Iraj; Abbaszadeh, Moloud; Assadi, Majid

2013-01-01

False-positive findings with myocardial perfusion imaging (MPI) have frequently been identified in the presence of left bundle branch block (LBBB) and tend to lower the accuracy of MPI in individuals with normal coronary angiographs. Pharmacologic stress is recognized as the preferred method for MPI in patients with LBBB. In contrast, very few studies have evaluated the effect of right bundle branch block (RBBB) on MPI, and there is no consensus regarding the selection of pharmacologic versus exercise stress during MPI for the RBBB patient. In this study, we present a 45-year-old man with RBBB, who has a normal coronary artery angiography, but who showed abnormal myocardial perfusion with exercise MPI, and normal perfusion on dipyridamole MPI. The aim of the study is to stimulate awareness that the stress method selected for patients with RBBB can potentially interfere with the accuracy of the data.

Effect of surfactants, gastric emptying, and dosage form on supersaturation of dipyridamole in an in vitro model simulating the stomach and duodenum.

PubMed

Mitra, A; Fadda, H M

2014-08-04

The purpose of this study was to investigate the influence of gastric emptying patterns, surfactants, and dosage form on the supersaturation of a poorly soluble weakly basic drug, dipyridamole, using an in vitro model mimicking the dynamic environment of the upper gastrointestinal tract, and, furthermore, to evaluate the usefulness of this model in establishing correlations to in vivo bioavailability for drugs with solubility/dissolution limited absorption. A simulated stomach duodenum model comprising four compartments was used to assess supersaturation and precipitation kinetics as a function of time. It integrates physiologically relevant fluid volumes, fluid transfer rates, and pH changes of the upper GI tract. Monoexponential gastric emptying patterns simulating the fasted state were compared to linear gastric emptying patterns simulating the fed state. The effect of different surfactants commonly used in oral preparations, specifically, sodium lauryl sulfate (SLS), poloxamer-188, and polysorbate-80, on dipyridamole supersaturation was investigated while maintaining surface tension of the simulated gastric fluids at physiological levels and without obtaining artificial micellar solubilization of the drug. The supersaturation behavior of different dose strengths of dipyridamole was explored. Significant levels of dipyridamole supersaturation were observed in the duodenal compartment under all the different in vivo relevant conditions explored. Dipyridamole supersaturation ratios of up to 11-fold have been observed, and supersaturation has been maintained for up to 120 min. Lower duodenal concentrations of dipyridamole were observed under linear gastric emptying patterns compared to mononexponential gastric emptying. The mean duodenal area under concentration-time curves (AUC60min) for the dipyridamole concentration profile in the duodenal compartment is significantly different for all the surfactants explored (P < 0.05). Our investigations with the different

Shape-Coexistence in ^191Tl and ^189Tl.

NASA Astrophysics Data System (ADS)

Reviol, W.; Riedinger, L. L.; Carpenter, M. P.; Fischer, S. M.; Janssens, R. V. F.; Nisius, D.; Moore, E. F.

1997-10-01

The Tl isotopes at A ~ 190 are, like the neighboring Hg and Pb nuclei, recognized for a multiplicity of shapes. These shapes reach from spherical or weakly deformed oblate to well-deformed and superdeformed prolate, as mainly inferred from γ -ray spectroscopic studies. We have previously reported on shape-coexistence phenomena in ^191Tl and ^189Tl(W. Reviol et al., Phys. Scr. T56, 167 (1995), and references therein.). Here, we will focus on new results on the ``normally" deformed states in both nuclei obtained from a recent and an upcoming experiment at GAMMASPHERE. The states in ^191Tl and ^189Tl are populated by the reactions ^159Tb(^36S,4n)^191Tl at E_lab = 165 MeV and ^156Gd(^37Cl,4n)^189Tl at E_lab = 171 MeV, respectively. One of the questions to be addressed is about the main level structure in the positive-parity branch of ^191Tl^2. Whether this structure is oblate-collective in nature, like the [505]9/2^- yrast band, we will try to answer on the basis of the available lifetime data.

Low-dose adenosine stress echocardiography: detection of myocardial viability.

PubMed

Djordjevic-Dikic, Ana; Ostojic, Miodrag; Beleslin, Branko; Nedeljkovic, Ivana; Stepanovic, Jelena; Stojkovic, Sinisa; Petrasinovic, Zorica; Nedeljkovic, Milan; Saponjski, Jovica; Giga, Vojislav

2003-06-03

The aim of this study was to evaluate the diagnostic potential of low-dose adenosine stress echocardiography in detection of myocardial viability. Vasodilation through low dose dipyridamole infusion may recruit contractile reserve by increasing coronary flow or by increasing levels of endogenous adenosine. Forty-three patients with resting dyssynergy, due to previous myocardial infarction, underwent low-dose adenosine (80, 100, 110 mcg/kg/min in 3 minutes intervals) echocardiography test. Gold standard for myocardial viability was improvement in systolic thickening of dyssinergic segments of >or= 1 grade at follow-up. Coronary angiography was done in 41 pts. Twenty-seven patients were revascularized and 16 were medically treated. Echocardiographic follow up data (12 +/- 2 months) were available in 24 revascularized patients. Wall motion score index improved from rest 1.55 +/- 0.30 to 1.33 +/- 0.26 at low-dose adenosine (p < 0.001). Of the 257 segments with baseline dyssynergy, adenosine echocardiography identified 122 segments as positive for viability, and 135 as necrotic since no improvement of systolic thickening was observed. Follow-up wall motion score index was 1.31 +/- 0.30 (p < 0.001 vs. rest). The sensitivity of adenosine echo test for identification of viable segments was 87%, while specificity was 95%, and diagnostic accuracy 90%. Positive and negative predictive values were 97% and 80%, respectively. Low-dose adenosine stress echocardiography test has high diagnostic potential for detection of myocardial viability in the group of patients with left ventricle dysfunction due to previous myocardial infarction. Low dose adenosine stress echocardiography may be adequate alternative to low-dose dobutamine test for evaluation of myocardial viability.

Low-dose adenosine stress echocardiography: Detection of myocardial viability

PubMed Central

Djordjevic-Dikic, Ana; Ostojic, Miodrag; Beleslin, Branko; Nedeljkovic, Ivana; Stepanovic, Jelena; Stojkovic, Sinisa; Petrasinovic, Zorica; Nedeljkovic, Milan; Saponjski, Jovica; Giga, Vojislav

2003-01-01

Objective The aim of this study was to evaluate the diagnostic potential of low-dose adenosine stress echocardiography in detection of myocardial viability. Background Vasodilation through low dose dipyridamole infusion may recruit contractile reserve by increasing coronary flow or by increasing levels of endogenous adenosine. Methods Forty-three patients with resting dyssynergy, due to previous myocardial infarction, underwent low-dose adenosine (80, 100, 110 mcg/kg/min in 3 minutes intervals) echocardiography test. Gold standard for myocardial viability was improvement in systolic thickening of dyssinergic segments of ≥ 1 grade at follow-up. Coronary angiography was done in 41 pts. Twenty-seven patients were revascularized and 16 were medically treated. Echocardiographic follow up data (12 ± 2 months) were available in 24 revascularized patients. Results Wall motion score index improved from rest 1.55 ± 0.30 to 1.33 ± 0.26 at low-dose adenosine (p < 0.001). Of the 257 segments with baseline dyssynergy, adenosine echocardiography identified 122 segments as positive for viability, and 135 as necrotic since no improvement of systolic thickening was observed. Follow-up wall motion score index was 1.31 ± 0.30 (p < 0.001 vs. rest). The sensitivity of adenosine echo test for identification of viable segments was 87%, while specificity was 95%, and diagnostic accuracy 90%. Positive and negative predictive values were 97% and 80%, respectively. Conclusion Low-dose adenosine stress echocardiography test has high diagnostic potential for detection of myocardial viability in the group of patients with left ventricle dysfunction due to previous myocardial infarction. Low dose adenosine stress echocardiography may be adequate alternative to low-dose dobutamine test for evaluation of myocardial viability. PMID:12812523

Surface defect free growth of a spin dimer TlCuCl{sub 3} compound crystals and investigations on its optical and magnetic properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ryu, Gihun, E-mail: G.Ryu@fkf.mpg.de; Son, Kwanghyo

A defect-free high quality single crystal of spin dimer TlCuCl{sub 3} compound is firstly synthesized at the optimal growth temperature using the vertical Bridgman method. In this study, we clearly found that the cupric chloride is easily decomposed into the Cl{sup −} deficient composition at ≥470 °C. The Cl{sup −}- related gas phase at the high temperature region also always gives rise to a pinhole-like surface defect at the surface of crystal. Therefore, we clearly verified an exotic anisotropic magnetic behavior (anisotropic ratio of M{sub b}/M{sub (201)} at 2 K, 7 T=10) using the defect-free TlCuCl{sub 3} crystals in thismore » three-dimensional spin dimer TlCuCl{sub 3} compound, relatively stronger magnetic ordering in the H//b than that of H//(201) direction at above the transition magnetic field. - Graphical abstract: A single crystal of spin dimer TlCuCl{sub 3} compound with a defect free is successfully synthesized on the basis of TG/DTA result. We newly found that this cupric chloride compound is easily decomposed into the Cl{sup −} deficient composition at ≥470 °C and Cl{sup −} related gas phases also give rise to the defects like a pinhole on the surface of TlCuCl{sub 3} crystal. Using the crystals with a surface defect free, we also clearly verified the crystal structure of spin dimer TlCuCl{sub 3} compound.« less

Na(23)K(9)Tl(15.3): An Unusual Zintl Compound Containing Apparent Tl(5)(7)(-), Tl(4)(8)(-), Tl(3)(7)(-), and Tl(5)(-) Anions.

PubMed

Dong, Zhen-Chao; Corbett, John D.

1996-05-22

Reaction of the neat elements in tantalum containers at 400 degrees C and then 150 degrees C gives the pure title phase. X-ray crystallography shows that the hexagonal structure (P6(3)/mmc, Z = 2, a = 11.235(1) Å, b = 30.133(5) Å) contains relatively high symmetry clusters Tl(5)(7)(-) (D(3)(h)()), Tl(4)(8)(-) (C(3)(v)(), approximately T(d)), and the new Tl(3)(7)(-) (D(infinity)(h)()) plus Tl(5)(-), the last two disordered over the same elongated site in 1:2 proportions. Cation solvation of these anions is tight and specific, providing good Coulombic trapping of weakly bound electrons on the isolated cluster anions. The observed disorder makes the compound structurally a Zintl phase with a closed shell electron count. EHMO calculations on the novel Tl(3)(7)(-) reveal some bonding similarities with the isoelectronic CO(2), with two good sigma(s,p) bonding and two weakly bonding pi MO's. The Tl-Tl bond lengths therein (3.14 Å) are evidently consistent with multiple bonding. The weak temperature-independent paramagnetism and metallic conductivity (rho(293) approximately 90 &mgr;Omega.cm) of the phase are discussed.

Microvascular autonomic dysfunction may justify false-positive stress myocardial perfusion imaging in patients with liver cirrhosis undergoing liver transplantation.

PubMed

Senzolo, M; Bassanello, M; Graziotto, A; Zucchetta, P; Cillo, U; Maraglino, G; Loreno, M; Bellotto, F; Davià, G; Burra, P

2008-01-01

Up to 15% of liver transplant candidates have asymptomatic coronary artery diseases, which increase the risk of cardiac complications during and after transplantation. The aim of this study was to prospectively investigate the usefulness of an integrated cardiological approach in cirrhotic patients undergoing liver transplantation. Twenty-four consecutive patients undergoing evaluation for liver transplantation were studied by assessing risk factors for coronary artery diseases, electrocardiogram with QTc interval determination, chest X-ray, echocardiography, 24-hour Holter monitor, myocardial perfusion scintigraphy (99mTc)MIBI-GSPECT at rest and after dipyridamole infusion. Cardiac (123)I-metaiodobenzylguanidine (MIBG) scan and coronarography were performed in patients with myocardial perfusion defects. Twenty three of 24 patients underwent successful liver transplantation; one patient died on the waiting list. Before liver transplantation, 29% of patients were diabetic and 41% were smokers. Eleven of 24 patients had a prolonged QTc interval, and 3/24 had positive myocardioscintigraphy after dipyridamole infusion: in two coronarography was negative, while the (123)I-MIBG washout was altered. No cardiac events were recorded during the short-and long-term follow-up after surgery. Predictive value of positive cardiac (99mTc)MIBI-GSPECT in patients with liver cirrhosis is low, and this may be due to alterations of cardiac microvascular tone as showed by cardiac (123)I-MIBG scan.

In Vitro Dissolution of Fluconazole and Dipyridamole in Gastrointestinal Simulator (GIS), Predicting in Vivo Dissolution and Drug-Drug Interaction Caused by Acid-Reducing Agents.

PubMed

Matsui, Kazuki; Tsume, Yasuhiro; Amidon, Gregory E; Amidon, Gordon L

2015-07-06

Weakly basic drugs typically exhibit pH-dependent solubility in the physiological pH range, displaying supersaturation or precipitation along the gastrointestinal tract. Additionally, their oral bioavailabilities may be affected by coadministration of acid-reducing agents that elevate gastric pH. The purpose of this study was to assess the feasibility of a multicompartmental in vitro dissolution apparatus, Gastrointestinal Simulator (GIS), in predicting in vivo dissolution of certain oral medications. In vitro dissolution studies of fluconazole, a BCS class I, and dipyridamole, a BCS class II weak bases (class IIb), were performed in the GIS as well as United States Pharmacopeia (USP) apparatus II and compared with the results of clinical drug-drug interaction (DDI) studies. In both USP apparatus II and GIS, fluconazole completely dissolved within 60 min regardless of pH, reflecting no DDI between fluconazole and acid-reducing agents in a clinical study. On the other hand, seven-fold and 15-fold higher concentrations of dipyridamole than saturation solubility were observed in the intestinal compartments in GIS with gastric pH 2.0. Precipitation of dipyridamole was also observed in the GIS, and the percentage of dipyridamole in solution was 45.2 ± 7.0%. In GIS with gastric pH 6.0, mimicking the coadministration of acid-reducing agents, the concentration of dipyridamole was equal to its saturation solubility, and the percentage of drug in solution was 9.3 ± 2.7%. These results are consistent with the clinical DDI study of dipyridamole with famotidine, which significantly reduced the Cmax and area under the curve. An In situ mouse infusion study combined with GIS revealed that high concentration of dipyridamole in the GIS enhanced oral drug absorption, which confirmed the supersaturation of dipyridamole. In conclusion, GIS was shown to be a useful apparatus to predict in vivo dissolution for BCS class IIb drugs.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matsunaga, Shigeo, E-mail: shigeo-m@mui.biglobe.ne.jp; Shuto, Takashi; Takase, Hajime

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 delayedmore » 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

Synthesis and reactivity of dimeric Ar'TlTlAr' and trimeric (Ar"T1)3 (Ar', Ar" = bulky terphenyl group) thallium(I) derivatives: Tl(I)-Tl(I) bonding in species ligated by monodentate ligands.

PubMed

Wright, Robert J; Phillips, Andrew D; Hino, Shirley; Power, Philip P

2005-04-06

The synthesis and characterization of three new organothallium(I) compounds are reported. Reaction of (Ar'Li)(2) (Ar' = C(6)H(3)-2,6-(C(6)H(3)-2,6-Pr(i)(2))(2)) and Ar"Li (Ar" = C(6)H(3)-2,6-(C(6)H(3)-2,6-Me(2))(2)) with TlCl in Et(2)O afforded (Ar'Tl)(2) (1) and (Ar' 'Tl)(3) (2). The "dithallene" 1 is the heaviest group 13 dimetallene and features a planar, trans-bent structure with Ar'Tl-Tl = 119.74(14) degrees and Tl-Tl = 3.0936(8) A. Compound 2 is the first structurally characterized neutral, three-membered ring species of formula c-(MR)(3) (M = Al-Tl; R = organo group). The Tl(3) ring has Tl-Tl distances in the range ca. 3.21-3.37 A as well as pyramidal Tl geometries. The Tl-Tl bonds in 1 and 2 are outside the range (2.88-2.97 A) of Tl-Tl single bonds in R(2)TlTlR(2) compounds. The weak Tl-Tl bonding in 1 and 2 leads to their dissociation into Ar'Tl and Ar' 'Tl monomers in hexane. The Ar'Tl monomer behaves as a Lewis base and readily forms a 1:1 donor-acceptor complex with B(C(6)F(5))(3) to give Ar'TlB(C(6)F(5))(3), 3. Adduct 3 features an almost linear thallium C(ipso)-Tl-B angle of 174.358(7) degrees and a Tl-B distance of 2.311(2) A, which indicates strong association. Treatment of 1 with a variety of reagents resulted in no reactions. The lower reactivity of 1 is in accord with the reluctance of Tl(I) to undergo oxidation to Tl(III) due to the unreactive character of the 6s(2) electrons.

Recovery of BMIPP uptake and regional wall motion in insulin resistant patients following angioplasty for acute myocardial infarction.

PubMed

Fujino, Takayuki; Ishii, Yoshinao; Takeuchi, Toshiharu; Hirasawa, Kunihiko; Tateda, Kunihiko; Kikuchi, Kenjiro; Hasebe, Naoyuki

2003-09-01

The effect of insulin resistance (IR) on the fatty acid metabolism of myocardium, and therefore on the recovery of left ventricular (LV) wall motion, has not been established in patients with acute myocardial infarction (AMI). A total of consecutive 58 non-diabetic AMI patients who had successfully undergone emergency coronary angioplasty were analyzed retrospectively. They were categorized into 2 groups, normal glucose tolerance (NGT) and impaired glucose tolerance (IGT), based on a 75-g oral glucose tolerance test (OGTT). The parameters of OGTT, myocardial scintigraphy (n=58) (thallium-201 (Tl) and iodine-123-beta-methyl-iodophenylpentadecanoic acid (BMIPP)) and left ventriculography (n=24) were compared in the 2 groups after reperfusion (acute phase) and 3-4 weeks after the AMI (chronic phase). The insulin resistance (IR), estimated by the serum concentration of insulin at 120 min (IRI 120') of the OGTT and by the HOMA (the homeostasis model assessment) index, was higher in the IGT group than in NGT group. An inverse correlation was found between the recovery of regional LV wall motion in the ischemic lesion and the IRI 120' and HOMA index. Although the recovery of BMIPP uptake from the acute to the chronic phase was higher in the IGT group, it was only correlated with the degree of IRI 120', not with the HOMA. IR accompanied by IGT can negatively influence the recovery of regional LV wall motion.

Comparison of conventional and cadmium-zinc-telluride single-photon emission computed tomography for analysis of thallium-201 myocardial perfusion imaging: an exploratory study in normal databases for different ethnicities.

PubMed

Ishihara, Masaru; Onoguchi, Masahisa; Taniguchi, Yasuyo; Shibutani, Takayuki

2017-12-01

The aim of this study was to clarify the differences in thallium-201-chloride (thallium-201) myocardial perfusion imaging (MPI) scans evaluated by conventional anger-type single-photon emission computed tomography (conventional SPECT) versus cadmium-zinc-telluride SPECT (CZT SPECT) imaging in normal databases for different ethnic groups. MPI scans from 81 consecutive Japanese patients were examined using conventional SPECT and CZT SPECT and analyzed with the pre-installed quantitative perfusion SPECT (QPS) software. We compared the summed stress score (SSS), summed rest score (SRS), and summed difference score (SDS) for the two SPECT devices. For a normal MPI reference, we usually use Japanese databases for MPI created by the Japanese Society of Nuclear Medicine, which can be used with conventional SPECT but not with CZT SPECT. In this study, we used new Japanese normal databases constructed in our institution to compare conventional and CZT SPECT. Compared with conventional SPECT, CZT SPECT showed lower SSS (p < 0.001), SRS (p = 0.001), and SDS (p = 0.189) using the pre-installed SPECT database. In contrast, CZT SPECT showed no significant difference from conventional SPECT in QPS analysis using the normal databases from our institution. Myocardial perfusion analyses by CZT SPECT should be evaluated using normal databases based on the ethnic group being evaluated.

Reduction of indium-111 platelet deposition on Dacron vascular grafts in humans by aspirin plus dipyridamole

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stratton, J.R.; Ritchie, J.L.

Aspirin plus dipyridamole reduces platelet accumulation on short-term Dacron vascular grafts in man. To determine whether drug inhibition of platelet deposition is sustained on older grafts, we studied 18 men aged 41 to 87 years who had Dacron aortic bifurcation grafts in place a mean of 43.4 months (range 9.8 to 121.0) before and during short-term therapy with aspirin (325 mg tid) plus dipyridamole (75 mg tid). During both the baseline and drug studies, indium-111 (/sup 111/In) platelet deposition was quantitated by two techniques, standard planar imaging performed at 24, 48, and 72 hr after injection of platelets and singlemore » photon emission computed tomographic imaging performed at 24 and 72 hr after injection. All analyses were performed in a blinded fashion. On both the planar and tomographic images, platelet accumulation on the graft was quantitated by a graft/blood ratio that compared activity in the graft to simultaneously collected whole blood /sup 111/In platelet activity. Aspirin plus dipyridamole reduced the tomographic graft/blood ratio at 24 hr (20.6 +/- 3.5 vs 17.3 +/- 2.5) (+/-SEM) and at 72 hr (29.0 +/- 4.8 vs 25.0 +/- 4.1) after injection of platelets (p = .02). Dacron vascular grafts. Similarly, the planar graft/blood ratio was reduced at 24 hr (2.7 +/- 0.5 vs 2.4 +/- 0.5), 48 hr (3.7 +/- 0.9 vs 3.1 +/- 0.7), and 72 hr (4.0 +/- 0.9 vs 3.6 +/- 0.8) (p = .04). We conclude that aspirin (325 mg tid) plus dipyridamole (75 mg tid) reduces platelet accumulation on long-term Dacron vascular grafts.« less

Phase diagrams of the sections As/sub 2/S/sub 3/-Tl/sub 3/AsS/sub 4/, Tl/sub 3/AsS/sub 4/-S, and Tl/sub 3/AsS/sub 4/-Tl/sub 2/S of the ternary system As-Tl-S

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vorob'ev, Yu.I.; Velikova, N.G.; Kirilenko, V.V.

1987-12-01

Using DTA and XPA methods, microstructural investigations, and microhardness measurements, phase diagrams of the quasibinary sections As/sub 2/S/sub 3/-Tl/sub 3/AsS/sub 4/, Tl/sub 3/AsS/sub 4/-S, and Tl/sub 3/AsS/sub 4/-Tl/sub 2/S, are characterized by five ternary compounds Tl/sub 3/As/sub 5/S/sub 10/, Tl/sub 9/As/sub 5/S/sub 15/, Tl/sub 9/As/sub 3/S/sub 13/, Tl/sub 3/AsS/sub 6/, and Tl/sub 8/As/sub 2/S/sub 9/, which decompose by peritectic reactions at 198, 307, 408, 362, and 318/degree/C, respectively. Interplanar spacings and line intensities are given for the detected compounds. Glass formation is considered in the Tl-As-S system.

Myocardial viability assessment after acute myocardial infarction: low-dose dobutamine echocardiography versus rest-redistribution thallium-201 SPECT.

PubMed

Castini, D; Bestetti, A; Garbin, M; Di Leo, C; Bigi, R; Sponzilli, C; Concardi, G; Gioventù, M; Tarolo, G L; Lombardi, F; Fiorentini, C

1999-09-01

The presence of tissue viability is of great importance in the prognostic work-up of patients recovering from acute myocardial infarction. However, uncertainty still exists concerning the optimal tool for its assessment. The present study was undertaken in order to compare low-dose dobutamine echocardiography and rest-redistribution thallium SPECT for predicting late improvement of regional left ventricular function after acute myocardial infarction. Fifteen patients undergoing coronary angiography, low-dose dobutamine echocardiography and rest-redistribution thallium SPECT after thrombolyzed anterior acute myocardial infarction were studied. A 3 month follow-up echocardiogram was performed in all patients and 9 underwent coronary revascularization. A significant (> or = 70%) residual stenosis of the infarct-related artery was present in 14 patients, whilst a total occlusion was observed in 1. At 3 month follow-up, 41% of the dyssynergic segments improved. The sensitivity, specificity and accuracy for late wall motion improvement was 61, 89 and 77% for low-dose dobutamine echocardiography and, respectively, 76, 45 and 58% for rest-redistribution thallium SPECT. Tissue viability was detected in 65 and 31% of dyssynergic segments by rest-redistribution thallium SPECT and low-dose dobutamine echocardiography, respectively (p < 0.001). The agreement between the two techniques was 48%. Low-dose dobutamine echocardiography is more accurate than rest-redistribution thallium SPECT for predicting 3 month wall motion improvement in patients with acute anterior myocardial infarction, mainly due to its significantly better specificity.

The possible protective effects of dipyridamole on ischemic reperfusion injury of priapism

PubMed Central

Karaguzel, Ersagun; Bayraktar, Cemil; Kutlu, Omer; Yulug, Esin; Mentese, Ahmet; Okatan, Ali Ertan; Colak, Fatih; Ozer, Serap; O.Kazaz, Ilke

2016-01-01

ABSTRACT Purpose To investigate the protective effects against ischemia reperfusion injury of dipyridamole in a model of induced priapism in rats. Materials and Methods Twenty-four male Sprague-Dawley rats were divided into four groups, control, P/R, P/R+DMSO and P/R+D. 3ml blood specimens were collected from vena cava inferior in order to determine serum MDA, IMA, TAS, TOS and OSI values, and penile tissue was taken for histopathological examination in control group. Priapism was induced in P/R group. After 1h, priapism was concluded and 30 min reperfusion was performed. In P/R+DMSO group 1ml/kg DMSO was administered intraperitoneally 30 min before reperfusion, while in P/R+D group 10mg/kg dipyridamole was administered intraperitoneally 30 min before reperfusion. Blood and penis specimens were collected after the end of 30 min reperfusion period. Sinusoidal area (µm2), tears in tunica albuginea and injury parameters in sinusoidal endothelium of penis were investigated. Results Histopathological examination revealed no significant changes in term of sinusoidal area. A decrease in tears was observed in P/R+D group compared to P/R group (p<0.05). Endothelial injury decreased in P/R+D group compared to P/R group (p>0.05). There were no significant differences in MDA and IMA values between groups. A significant increase in TOS and OSI values was observed in P/R+D group compared to P/R group. A significant decrease in TAS levels was observed in P/R+D group compared to the P/R group. Conclusions The administration of dipyridamole before reperfusion in ischemic priapism model has a potential protective effect against histopathological injury of the penis. PMID:27136481

Aging effects in bulk and fiber TlBr-TlI

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wysocki, J.A.; Wilson, R.G.; Standlee, A.G.

1988-05-01

A study of optical aging in bulk and extruded fibers of thallium bromo-iodide (TlBr-TlI) is presented. A variety of techniques including secondary ion mass spectrometry (SIMS), powder neutron and x-ray diffraction, infrared spectroscopy, and electron paramagnetic resonance (EPR) spectroscopy are used to probe the chemical and structural properties of both pristine and aged material. High concentration levels of a hydrogen bearing impurity have been detected by SIMS and neutron scattering in aged TlBr-TlI, and have been shown to be localized in the surface layers of fibers as well as bulk samples. We present EPR evidence which indicates that the hydrogenmore » bearing impurity is water.« less

Quantification of Regional Myocardial Oxygenation by Magnetic Resonance Imaging: Validation with Positron Emission Tomography

PubMed Central

McCommis, Kyle S.; Goldstein, Thomas A.; Abendschein, Dana R.; Herrero, Pilar; Misselwitz, Bernd; Gropler, Robert J.; Zheng, Jie

2011-01-01

Background A comprehensive evaluation of myocardial ischemia requires measures of both oxygen supply and demand. Positron emission tomography (PET) is currently the gold standard for such evaluations, but its use is limited due to its ionizing radiation, limited availability, and high cost. A cardiac magnetic resonance imaging (MRI) method was developed for assessing myocardial oxygenation. The purpose of this study was to evaluate and validate this technique compared to PET during pharmacologic stress in a canine model of coronary artery stenosis. Methods and Results Twenty-one beagles and small mongrel dogs without coronary artery stenosis (controls), or with moderate to severe acute coronary artery stenosis underwent MRI and PET imaging at rest and during dipyridamole vasodilation or dobutamine stress to induce a wide range of changes in cardiac perfusion and oxygenation. MRI first-pass perfusion imaging was performed to quantify myocardial blood flow (MBF) and volume (MBV). The MRI blood-oxygen-level-dependent (BOLD) technique was used to determine the myocardial oxygen extraction fraction (OEF) during pharmacologic hyperemia. Myocardial oxygen consumption (MVO2) was determined by Fick’s law. In the same dogs, 15O-water and 11C-acetate were used to measure MBF and MVO2, respectively, by PET. Regional assessments were performed for both MR and PET. MRI data correlated nicely with PET values for MBF (R2 = 0.79, P < 0.001), MVO2 (R2 = 0.74, P < 0.001), and OEF (R2 = 0.66, P < 0.01). Conclusions Cardiac MRI methods may provide an alternative to radionuclide imaging in settings of myocardial ischemia. Our newly developed quantitative MRI oxygenation imaging technique may be a valuable non-invasive tool to directly evaluate myocardial energetics and efficiency. PMID:19933371

Utilization of Gastrointestinal Simulator, an in Vivo Predictive Dissolution Methodology, Coupled with Computational Approach To Forecast Oral Absorption of Dipyridamole.

PubMed

Matsui, Kazuki; Tsume, Yasuhiro; Takeuchi, Susumu; Searls, Amanda; Amidon, Gordon L

2017-04-03

Weakly basic drugs exhibit a pH-dependent dissolution profile in the gastrointestinal (GI) tract, which makes it difficult to predict their oral absorption profile. The aim of this study was to investigate the utility of the gastrointestinal simulator (GIS), a novel in vivo predictive dissolution (iPD) methodology, in predicting the in vivo behavior of the weakly basic drug dipyridamole when coupled with in silico analysis. The GIS is a multicompartmental dissolution apparatus, which represents physiological gastric emptying in the fasted state. Kinetic parameters for drug dissolution and precipitation were optimized by fitting a curve to the dissolved drug amount-time profiles in the United States Pharmacopeia apparatus II and GIS. Optimized parameters were incorporated into mathematical equations to describe the mass transport kinetics of dipyridamole in the GI tract. By using this in silico model, intraluminal drug concentration-time profile was simulated. The predicted profile of dipyridamole in the duodenal compartment adequately captured observed data. In addition, the plasma concentration-time profile was also predicted using pharmacokinetic parameters following intravenous administration. On the basis of the comparison with observed data, the in silico approach coupled with the GIS successfully predicted in vivo pharmacokinetic profiles. Although further investigations are still required to generalize, these results indicated that incorporating GIS data into mathematical equations improves the predictability of in vivo behavior of weakly basic drugs like dipyridamole.

Regional cardiac wall motion from gated myocardial perfusion SPECT studies

NASA Astrophysics Data System (ADS)

Smith, M. F.; Brigger, P.; Ferrand, S. K.; Dilsizian, V.; Bacharach, S. L.

1999-06-01

A method for estimating regional epicardial and endocardial wall motion from gated myocardial perfusion SPECT studies has been developed. The method uses epicardial and endocardial boundaries determined from four long-axis slices at each gate of the cardiac cycle. The epicardial and endocardial wall position at each time gate is computed with respect to stationary reference ellipsoids, and wall motion is measured along lines normal to these ellipsoids. An initial quantitative evaluation of the method was made using the beating heart from the dynamic mathematical cardiac torso (MCAT) phantom, with and without a 1.5-cm FWHM Gaussian blurring filter. Epicardial wall motion was generally well-estimated within a fraction of a 3.56-mm voxel, although apical motion was overestimated with the Gaussian filter. Endocardial wall motion was underestimated by about two voxels with and without the Gaussian filter. The MCAT heart phantom was modified to model hypokinetic and dyskinetic wall motion. The wall motion analysis method enabled this abnormal motion to be differentiated from normal motion. Regional cardiac wall motion also was analyzed for /sup 201/Tl patient studies. Estimated wall motion was consistent with a nuclear medicine physician's visual assessment of motion from gated long-axis slices for male and female study examples. Additional research is required for a comprehensive evaluation of the applicability of the method to patient studies with normal and abnormal wall motion.

Myocardial perfusion abnormalities in asymptomatic patients with systemic lupus erythematosus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hosenpud, J.D.; Montanaro, A.; Hart, M.V.

1984-08-01

Accelerated coronary artery disease and myocardial infarction in young patients with systemic lupus erythematosus is well documented; however, the prevalence of coronary involvement is unknown. Accordingly, 26 patients with systemic lupus were selected irrespective of previous cardiac history to undergo exercise thallium-201 cardiac scintigraphy. Segmental perfusion abnormalities were present in 10 of the 26 studies (38.5 percent). Five patients had reversible defects suggesting ischemia, four patients had persistent defects consistent with scar, and one patient had both reversible and persistent defects in two areas. There was no correlation between positive thallium results and duration of disease, amount of corticosteroid treatment,more » major organ system involvement or age. Only a history of pericarditis appeared to be associated with positive thallium-201 results (p less than 0.05). It is concluded that segmental myocardial perfusion abnormalities are common in patients with systemic lupus erythematosus. Whether this reflects large-vessel coronary disease or small-vessel abnormalities remains to be determined.« less

19 CFR 201.201 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-04-01

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19 CFR 201.201 - Definitions.

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2013-04-01

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19 CFR 201.201 - Definitions.

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2011-04-01

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19 CFR 201.201 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-04-01

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19 CFR 201.201 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-04-01

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Nuclear cardiology: Myocardial perfusion and function

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seldin, D.W.

1991-08-01

Myocardial perfusion studies continue to be a major focus of research, with new investigations of the relationship of exercise-redistribution thallium imaging to diagnosis, prognosis, and case management. The redistribution phenomenon, which seemed to be fairly well understood a few years ago, is now recognized to be much more complex than originally thought, and various strategies have been proposed to clarify the meaning of persistent defects. Pharmacologic intervention with dipyridamole and adenosine has become available as an alternative to exercise, and comparisons with exercise imaging and catheterization results have been described. Thallium itself is no longer the sole single-photon perfusion radiopharmaceutical;more » two new technetium agents are now widely available. In addition to perfusion studies, advances in the study of ventricular function have been made, including reports of studies performed in conjunction with technetium perfusion studies, new insights into cardiac physiology, and the prognostic and case-management information that function studies provide. Finally, work has continued with monoclonal antibodies for the identification of areas of myocyte necrosis. 41 references.« less

Synthesis of a new photoreactive derivative of dipyridamole and its use in the manufacture of artificial surfaces with low thrombogenicity.

PubMed

Aldenhoff, Y B; Pijpers, A P; Koole, L H

1997-01-01

Photoimmobilization of dipyridamole (Persantin) was accomplished through the use of a new synthetic conjugate molecule, 1. Persantin is a powerful inhibitor of platelet activation and aggregation and is widely used as a vasodilator. Conjugate 1 consists of triply protected dipyridamole [three of the four hydroxyl groups carry a tert-butyldimethylsilyl (TBDMS) protective group) and the photoreactive 4-azidobenzoyl group. A short hydrophilic spacer chain, derived from triethylene glycol, separates the protected dipyridamole system and the photoreactive group. Compound 1 was immobilized on polyurethane sheets (Pellethane D-55) through irradiation with ultraviolet (UV) light, and the protective groups were removed afterward. The resulting modified polyurethane surfaces were characterized by different physicochemical techniques: UV extinction, contact angle measurements (captive bubble technique), and X-ray photoelectron spectroscopy (XPS). The UV extinction measurements showed the presence of 13 +/- 1 nmol of immobilized dipyridamole/cm2. The contact angle measurements revealed that the modified surface was markedly more hydrophilic than the control (i.e. unmodified polyurethane). XPS measurements clearly established the presence of immobilized dipyridamole in the outermost layers of the modified surface. This was especially clear from the XPS spectra recorded at a low take-off angle (approximately 6 degrees). Furthermore, the XPS spectra showed that the TBDMS protective groups had been quantitatively removed during the deprotection/washing treatment. The in vitro blood compatibility of the modified surface was studied with the thrombin generation assay as developed in our group, as well as with scanning electron microscopy. The thrombin generation test produced a lag time of 1275 s for the modified surface, as opposed to 569 s for the control. Scanning electron microscopy showed that far fewer platelets adhere to the modified surface (approximately 7 x 10(3)/mm2) as

Scaled Hartree-Fock force field calculations for organothallium compounds: Normal-mode analysis for TlCH sub 3 Tl(CH sub 3 ) sub 2 sup + , Tl(CH sub 3 ) sub 3 , Tl(CH sub 3 ) sub 2 Br, and Tl(CH sub 3 ) sub 4 sup minus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schwerdtfeger, P.; Bowmaker, G.A.; Boyd, P.D.W.

1990-02-01

In a recent paper we presented Hartree-Fock (HF) calculations for aliphatic organothallium compounds. The diagonal HF force constants obtained from a Fletcher-Powell geometry optimization are now used for a normal-mode analysis of TlCH{sub 3}, Tl(CH{sub 3}){sub 2}{sup +}, Tl(CH{sub 3}){sub 3}, Tl(CH{sub 3}){sub 2}Br, and Tl(CH{sub 3}){sub 4}{sup {minus}}. In order to calculate frequencies comparable to experimental values, the HF force field has been scaled by using scaling factors obtained from experimental infrared and Raman measurements on Tl(CH{sub 3}){sub 2}{sup +} and TlBr. The vibrational spectra of Tl(CH{sub 3}){sub 2}{sup +} were remeasured (infrared and Raman) in order to obtainmore » an accurate force field. Predictions are made for the vibrational spectrum of the as yet undetected TlCH{sub 3} molecule. Experimental infrared and Raman results for Tl(CH{sub 3}){sub 3} compare reasonably well with our calculated frequencies. Relativistic and correlation effects are analyzed for the vibrational frequencies of Tl(CH{sub 3}){sub 2}{sup +}.« less

[Intracoronary, human autologous stem cell transplantation for myocardial regeneration following myocardial infarction].

PubMed

Strauer, B E; Brehm, M; Zeus, T; Gattermann, N; Hernandez, A; Sorg, R V; Kögler, G; Wernet, P

2001-08-24

The regenerative potential of human autologous adult stem cells on myocardial regeneration and neovascularisation after myocardial infarction may contribute to healing of the infarction area. But no clinical application has previously been reported. We here describe for the first time the results of this method applied in a patient who had sustained an acute myocardial infarction. 14 hours after the onset of left precordial pain a 46-year-old man was admitted to our hospital for interventional diagnosis and treatment. Coronary angiography demonstrated occlusion of the anterior descending branch of the left coronary artery with transmural infarction. This was treated by percutaneous transluminal catheter angioplasty and stent placement. Mononuclear bone marrow cells of the patient were prepared and 6 days after infaction 1,2 infinity 107 cells were transplanted at low pressure via a percutaneous transluminal catheter placed in the infarct-related artery. Before and 10 weeks after this procedure left ventricular function, infarct size, ventricular geometry and myocardial perfusion were measured by (201)thallium SPECT both at rest and on exercise, together with bull's-eye analysis, dobutamine stress echocardiography, right heart catheterisation and radionuclide ventriculography. At 10 weeks after the stem cell transplantation the transmural infarct area had been reduced from 24.6 % to 15.7 % of left ventricular circumference, while ejection fraction, cardiac index and stroke volume had increased by 20-30 %. On exercise the end diastolic volume had decreased by 30 % and there was a comparable fall in left ventricular filling pressure (mean pulmonary capillary pressure). These results for the first time demonstrate that selective intracoronary transplantation of human autologous adult stem cells is possible under clinical conditions and that it can lead to regeneration of the myocardial scar after transmural infarction. The therapeutic effects may be ascribed to stem

Improvement of Hyperemic Myocardial Oxygen Extraction Fraction Estimation By A Diffusion Prepared Sequence

PubMed Central

McCommis, Kyle S.; Koktzoglou, Ioannis; Zhang, Haosen; Goldstein, Thomas A.; Northrup, Benjamin E.; Li, Debiao; Gropler, Robert J.; Zheng, Jie

2010-01-01

Myocardial oxygen extraction fraction (OEF) during hyperemia can be estimated using a double-inversion-recovery (DIR) prepared T2-weighted black-blood sequence. Severe irregular ECG-triggering due to elevated heart rate and/or arrhythmias may render it difficult to adequately suppress the flowing left ventricle blood signal and thus potentially cause errors in the estimates of myocardial OEF. Thus, the goal of this study was to evaluate another black-blood technique, a diffusion-weighted (DW)-prepared TSE sequence for its ability to determine regional myocardial OEF during hyperemia. Control dogs and dogs with acute coronary artery stenosis were imaged with both the DIR- and DW-prepared TSE sequences at rest and during either dipyridamole or dobutamine hyperemia. Validation of MRI OEF estimates was performed using blood sampling from the artery and coronary sinus in control dogs. The two methods showed comparable correlations with blood sampling results (R2 = 0.9). Similar OEF estimations for all dogs were observed except for the group of dogs with severe coronary stenosis during dobutamine stress. In these dogs, the DW method provided more physiologically reasonable OEF (hyperemic OEF = 0.75 ± 0.08 vs resting OEF of 0.6) than the DIR method (hyperemic OEF = 0.56 ± 0.10). DW-preparation may be a valuable alternative for more accurate oxygenation measurements during irregular ECG-triggering. PMID:20512871

In vivo quantitation of platelet deposition on human peripheral arterial bypass grafts using indium-111-labeled platelets. Effect of dipyridamole and aspirin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pumphrey, C.W.; Chesebro, J.H.; Dewanjee, M.K.

Indium-111-labeled autologous platelets, injected 48 hours after operation, were used to evaluate the thrombogenicity of prosthetic material and the effect of platelet inhibitor therapy in vivo. Dacron double-velour (Microvel) aortofemoral artery bifurcation grafts were placed in 16 patients and unilateral polytetrafluoroethylene femoropopliteal grafts were placed in 10 patients. Half the patients in each group received platelet inhibitors before operation (dipyridamole, 100 mg 4 times a day) and after operation (dipyridamole, 75 mg, and acetylsalicylic acid, 325 mg 3 times a day); the rest of the patients served as control subjects. Five-minute scintigrams of the graft region were taken with amore » gamma camera interfaced with a computer 48, 72, and 96 hours after injection of the labeled platelets. Platelet deposition was estimated from the radioactivities of the grafts and expressed as counts per 100 pixels per microcurie injected. Dipyridamole and aspirin therapy significantly reduced the number of platelets deposited on Dacron grafts and prevented platelet accumulation over 3 days. With the small amount of platelet deposition on polytetrafluoroethylene femoropopliteal artery grafts even in control patients, platelet inhibitor therapy had no demonstrable effect on platelet deposition on these grafts. It is concluded that (1) platelet deposition on vascular grafts in vivo can be quantitated by noninvasive methods, and (2) dipyridamole and aspirin therapy reduced platelet deposition on Dacron aortofemoral artery grafts.« less

SoTL in Verse

ERIC Educational Resources Information Center

Gilpin, Lorraine S.

2013-01-01

This piece offers an overview of the Scholarship of Teaching and Learning (SoTL) in a nontraditional genre. It glances backward to the catalyst for the movement and traverses the context of SoTL today. Grounded in foundational literature of the field, it explores ideas about SoTL, including its purpose, nature, and characteristics. It underscores…

(Tl, Sb) and (Tl, Bi) binary surface reconstructions on Ge(111) substrate

NASA Astrophysics Data System (ADS)

Gruznev, D. V.; Bondarenko, L. V.; Tupchaya, A. Y.; Yakovlev, A. A.; Mihalyuk, A. N.; Zotov, A. V.; Saranin, A. A.

2018-03-01

2D compounds made of Group-III and Group-V elements on the surface of silicon and germanium attract considerable attention due to prospects of creating III-V binary monolayers, which are predicted to hold advanced physical properties. In the present work, we have investigated two such systems, (Tl, Sb)/Ge(111) and (Tl, Bi)/Ge(111) using scanning tunneling microscopy, low energy electron diffraction observations and density-functional-theory calculations. In addition to the previously reported surface structures of 2D (Tl, Sb) and (Tl, Bi) compounds on Si(111), we found new ones, namely, √{ 7} × √{ 7} and 3 × 3. Formation processes and plausible models of their atomic arrangements are discussed.

GRAVIMETRIC DETERMINATION OF PLATINIUM, PALLADIUM, RUTHENIUM, RHODIUM AS TlPtS$sub 3$, TlPd$sub 2$S$sub 3$, TlRu$sub 2$S$sub 6$, TlRh$sub 2$S$sub 4$ (in Russian)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rudnev, N.A.; Malofeeva, G.I.

1963-07-01

Gravimetric methods were developed for the determination of microamounts of Ru, Rh, Pt, and Pd as TlRu/sub 2/S/sub 6/, TlRh/sub 2/S/sub 4/ TlPtS/sub 3/, and TlPd/sub 2/S/sub 3/. The methods are simpl e, rapid, and satisfactorily accurate. (auth)

19 CFR 201.141-201.148 - [Reserved

Code of Federal Regulations, 2010 CFR

2010-04-01

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19 CFR 201.131-201.139 - [Reserved

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2010-04-01

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19 CFR 201.152-201.159 - [Reserved

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19 CFR 201.171-201.999 - [Reserved

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19 CFR 201.112-201.129 - [Reserved

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19 CFR 201.161-201.169 - [Reserved

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19 CFR 201.161-201.169 - [Reserved

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19 CFR 201.171-201.999 - [Reserved

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19 CFR 201.171-201.999 - [Reserved

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19 CFR 201.112-201.129 - [Reserved

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19 CFR 201.152-201.159 - [Reserved

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2011-04-01

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19 CFR 201.141-201.148 - [Reserved

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2012-04-01

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Code of Federal Regulations, 2014 CFR

2014-04-01

... 19 Customs Duties 3 2014-04-01 2014-04-01 false [Reserved] 201.152-201.159 Section 201.152-201.159 Customs Duties UNITED STATES INTERNATIONAL TRADE COMMISSION GENERAL RULES OF GENERAL APPLICATION.... International Trade Commission §§ 201.152-201.159 [Reserved] ...

19 CFR 201.131-201.139 - [Reserved

Code of Federal Regulations, 2012 CFR

2012-04-01

... 19 Customs Duties 3 2012-04-01 2012-04-01 false [Reserved] 201.131-201.139 Section 201.131-201.139 Customs Duties UNITED STATES INTERNATIONAL TRADE COMMISSION GENERAL RULES OF GENERAL APPLICATION.... International Trade Commission §§ 201.131-201.139 [Reserved] ...

19 CFR 201.152-201.159 - [Reserved

Code of Federal Regulations, 2013 CFR

2013-04-01

... 19 Customs Duties 3 2013-04-01 2013-04-01 false [Reserved] 201.152-201.159 Section 201.152-201.159 Customs Duties UNITED STATES INTERNATIONAL TRADE COMMISSION GENERAL RULES OF GENERAL APPLICATION.... International Trade Commission §§ 201.152-201.159 [Reserved] ...

19 CFR 201.141-201.148 - [Reserved

Code of Federal Regulations, 2013 CFR

2013-04-01

... 19 Customs Duties 3 2013-04-01 2013-04-01 false [Reserved] 201.141-201.148 Section 201.141-201.148 Customs Duties UNITED STATES INTERNATIONAL TRADE COMMISSION GENERAL RULES OF GENERAL APPLICATION.... International Trade Commission §§ 201.141-201.148 [Reserved] ...

19 CFR 201.112-201.129 - [Reserved

Code of Federal Regulations, 2013 CFR

2013-04-01

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19 CFR 201.161-201.169 - [Reserved

Code of Federal Regulations, 2014 CFR

2014-04-01

... 19 Customs Duties 3 2014-04-01 2014-04-01 false [Reserved] 201.161-201.169 Section 201.161-201.169 Customs Duties UNITED STATES INTERNATIONAL TRADE COMMISSION GENERAL RULES OF GENERAL APPLICATION.... International Trade Commission §§ 201.161-201.169 [Reserved] ...

19 CFR 201.131-201.139 - [Reserved

Code of Federal Regulations, 2014 CFR

2014-04-01

... 19 Customs Duties 3 2014-04-01 2014-04-01 false [Reserved] 201.131-201.139 Section 201.131-201.139 Customs Duties UNITED STATES INTERNATIONAL TRADE COMMISSION GENERAL RULES OF GENERAL APPLICATION.... International Trade Commission §§ 201.131-201.139 [Reserved] ...

19 CFR 201.131-201.139 - [Reserved

Code of Federal Regulations, 2011 CFR

2011-04-01

... 19 Customs Duties 3 2011-04-01 2011-04-01 false [Reserved] 201.131-201.139 Section 201.131-201.139 Customs Duties UNITED STATES INTERNATIONAL TRADE COMMISSION GENERAL RULES OF GENERAL APPLICATION.... International Trade Commission §§ 201.131-201.139 [Reserved] ...

19 CFR 201.161-201.169 - [Reserved

Code of Federal Regulations, 2012 CFR

2012-04-01

... 19 Customs Duties 3 2012-04-01 2012-04-01 false [Reserved] 201.161-201.169 Section 201.161-201.169 Customs Duties UNITED STATES INTERNATIONAL TRADE COMMISSION GENERAL RULES OF GENERAL APPLICATION.... International Trade Commission §§ 201.161-201.169 [Reserved] ...

19 CFR 201.104-201.109 - [Reserved

Code of Federal Regulations, 2012 CFR

2012-04-01

... 19 Customs Duties 3 2012-04-01 2012-04-01 false [Reserved] 201.104-201.109 Section 201.104-201.109 Customs Duties UNITED STATES INTERNATIONAL TRADE COMMISSION GENERAL RULES OF GENERAL APPLICATION.... International Trade Commission §§ 201.104-201.109 [Reserved] ...

19 CFR 201.141-201.148 - [Reserved

Code of Federal Regulations, 2011 CFR

2011-04-01

... 19 Customs Duties 3 2011-04-01 2011-04-01 false [Reserved] 201.141-201.148 Section 201.141-201.148 Customs Duties UNITED STATES INTERNATIONAL TRADE COMMISSION GENERAL RULES OF GENERAL APPLICATION.... International Trade Commission §§ 201.141-201.148 [Reserved] ...

19 CFR 201.161-201.169 - [Reserved

Code of Federal Regulations, 2013 CFR

2013-04-01

... 19 Customs Duties 3 2013-04-01 2013-04-01 false [Reserved] 201.161-201.169 Section 201.161-201.169 Customs Duties UNITED STATES INTERNATIONAL TRADE COMMISSION GENERAL RULES OF GENERAL APPLICATION.... International Trade Commission §§ 201.161-201.169 [Reserved] ...

19 CFR 201.104-201.109 - [Reserved

Code of Federal Regulations, 2011 CFR

2011-04-01

... 19 Customs Duties 3 2011-04-01 2011-04-01 false [Reserved] 201.104-201.109 Section 201.104-201.109 Customs Duties UNITED STATES INTERNATIONAL TRADE COMMISSION GENERAL RULES OF GENERAL APPLICATION.... International Trade Commission §§ 201.104-201.109 [Reserved] ...

19 CFR 201.152-201.159 - [Reserved

Code of Federal Regulations, 2012 CFR

2012-04-01

... 19 Customs Duties 3 2012-04-01 2012-04-01 false [Reserved] 201.152-201.159 Section 201.152-201.159 Customs Duties UNITED STATES INTERNATIONAL TRADE COMMISSION GENERAL RULES OF GENERAL APPLICATION.... International Trade Commission §§ 201.152-201.159 [Reserved] ...

19 CFR 201.104-201.109 - [Reserved

Code of Federal Regulations, 2014 CFR

2014-04-01

... 19 Customs Duties 3 2014-04-01 2014-04-01 false [Reserved] 201.104-201.109 Section 201.104-201.109 Customs Duties UNITED STATES INTERNATIONAL TRADE COMMISSION GENERAL RULES OF GENERAL APPLICATION.... International Trade Commission §§ 201.104-201.109 [Reserved] ...

19 CFR 201.104-201.109 - [Reserved

Code of Federal Regulations, 2013 CFR

2013-04-01

... 19 Customs Duties 3 2013-04-01 2013-04-01 false [Reserved] 201.104-201.109 Section 201.104-201.109 Customs Duties UNITED STATES INTERNATIONAL TRADE COMMISSION GENERAL RULES OF GENERAL APPLICATION.... International Trade Commission §§ 201.104-201.109 [Reserved] ...

Study of controlled-release floating tablets of dipyridamole using the dry-coated method.

PubMed

Chen, Kai; Wen, Haoyang; Yang, Feifei; Yu, Yibin; Gai, Xiumei; Wang, Haiying; Li, Pingfei; Pan, Weisan; Yang, Xinggang

2018-01-01

Dipyridamole (DIP), having a short biological half-life, has a narrow absorption window and is primarily absorbed in the stomach. So, the purpose of this study was to prepare controlled-release floating (CRF) tablets of dipyridamole by the dry-coated method. The influence of agents with different viscosity, hydroxypropylmethylcellulose (HPMC) and polyvinylpyrollidon K30 (PVP K30) in the core tablet and low-viscosity HPMC and PVP K30 in the coating layer on drug release, were investigated. Then, a study with a three-factor, three-level orthogonal experimental design was used to optimize the formulation of the CRF tablets. After data processing, the optimized formulation was found to be: 80 mg HPMC K4M in the core tablet, 80 mg HPMC E15 in core tablet and 40 mg PVP K30 in the coating layer. Moreover, an in vitro buoyancy study showed that the optimized formulation had an excellent floating ability and could immediately float without a lag time and this lasted more than 12 h. Furthermore, an in vivo gamma scintigraphic study showed that the gastric residence time of the CRF tablet was about 8 h.

Characterization of pixelated TlBr detectors with Tl electrodes

NASA Astrophysics Data System (ADS)

Hitomi, Keitaro; Onodera, Toshiyuki; Kim, Seong-Yun; Shoji, Tadayoshi; Ishii, Keizo

2014-05-01

A 4.36-mm-thick pixelated thallium bromide (TlBr) detector with Tl electrodes was fabricated from a crystal grown by the traveling molten zone method using zone-purified material. The detector had four 1×1 mm2 pixelated anodes. The detector performance was characterized at room temperature. The mobility-lifetime products of electrons for each pixel of the TlBr detector were measured to be >2.8×10-3 cm2/V. The four pixelated anodes of the detector exhibited energy resolutions of 1.5-1.8% full width at half maximum (FWHM) for 662-keV gamma rays for single-pixel events with the depth correction method. An energy resolution of 4.5% FWHM for 662-keV gamma rays was obtained from a reconstructed energy spectrum using two-pixel events from the two pixelated anodes on the detector.

Timing Performance of TlBr Detectors

NASA Astrophysics Data System (ADS)

Hitomi, Keitaro; Tada, Tsutomu; Onodera, Toshiyuki; Shoji, Tadayoshi; Kim, Seong-Yun; Xu, Yuanlai; Ishii, Keizo

2013-08-01

The timing performance of TlBr detectors was evaluated at room temperature (22 °C). 0.5-mm-thick planar TlBr detectors with Tl circular electrodes with a diameter of 3 mm were fabricated from TlBr crystals grown by the traveling molten zone method using a zone-purified material. The pulse rise time of the TlBr detector was measured using a digital oscilloscope as the cathode surface of the device was irradiated with a 22Na gamma-ray source. Coincidence timing spectra were obtained between the TlBr detector and a BaF2 scintillation detector when both detectors were irradiated with 511 keV positron annihilation gamma-rays. The timing resolution of the TlBr detector was found to be inversely proportional to the applied bias voltage. The TlBr detector, in coincidence with the BaF2 detector, exhibited timing resolutions characterized by a 6.5 ns full width at half maximum (FWHM) and an 8.5 ns FWHM with and without an energy window of 350 keV-560 keV, respectively.

Tl(I) and Tl(III) activate both mitochondrial and extrinsic pathways of apoptosis in rat pheochromocytoma (PC12) cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hanzel, Cecilia Eliana; Verstraeten, Sandra Viviana

2009-04-01

Thallium (Tl) is a highly toxic metal though yet its mechanisms are poorly understood. Previously, we demonstrated that rat pheochromocytoma (PC12) cells exposure to thallous (Tl(I)) or thallic (Tl(III)) cations leads to mitochondrial damage and reduced cell viability. In the present work we comparatively characterized the possible pathways involved in Tl(I)- and Tl(III)- (10-100 {mu}M) mediated decrease in PC12 cells viability. We observed that these cations do not cause cell necrosis but significantly increased the number of cells with apoptotic features. Both cations lead to Bax oligomerization and caused apoptosis inducing factor (AIF), endonuclease G (Endo G), and cytochrome cmore » release from mitochondria, but they did not activate caspase dependent DNAse (CAD). Tl(I)- and Tl(III)-dependent caspases 9 and 3 activation followed similar kinetics, with maximal effects at 18 h of incubation. In addition, Tl(I) promoted phosphatidylserine (PS) exposure. Tl(III) induced 2- and 18-fold increase in Fas content and caspase 8 activity, respectively. Together, experimental results show that Tl(I) and Tl(III) induce PC12 cells apoptosis, although differential pathways are involved. While Tl(I)-mediated cell apoptosis was mainly associated with mitochondrial damage, Tl(III) showed a mixed effect triggering both the intrinsic and extrinsic pathways of apoptosis. These findings contribute to a better understanding of the mechanisms underlying Tl-induced loss of cell viability in PC12 cells.« less

Assessment of residual tissue viability by exercise testing in recent myocardial infarction: comparison of the electrocardiogram and myocardial perfusion scintigraphy.

PubMed

Margonato, A; Ballarotto, C; Bonetti, F; Cappelletti, A; Sciammarella, M; Cianflone, D; Chierchia, S L

1992-04-01

The assessment of residual myocardial viability in infarcted areas is relevant for subsequent management and prognosis but requires expensive technology. To evaluate the possibility that simple, easily obtainable clinical markers may detect the presence of within-infarct viable tissue, the significance of exercise-induced ST elevation occurring in leads exploring the area of a recent Q wave myocardial infarction was assessed. Twenty-five patients with recent (less than 6 months) myocardial infarction were studied. All had angiographically documented coronary artery disease, diagnostic Q waves (n = 24) or negative T waves (n = 25) on the rest 12-lead electrocardiogram and exhibited during exercise greater than or equal to 1.5 mm ST segment elevation (n = 17) or isolated T wave pseudonormalization (n = 8) in the infarct-related leads. ST-T wave changes were reproduced in all patients during thallium-201 exercise myocardial scintigraphy. A fixed perfusion defect was observed in 24 of the 25 patients. A reversible defect was seen in 16 (94%) of 17 patients who exhibited transient ST elevation during exercise but in only 4 (50%) of the 8 patients who had only T wave pseudonormalization. In conclusion, in patients with recent myocardial infarction, analysis of simple ST segment variables obtained during exercise testing may allow a first-line discrimination of those who may potentially benefit from a revascularization procedure.

48 CFR 201.201-1 - The two councils.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false The two councils. 201.201-1 Section 201.201-1 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE GENERAL FEDERAL ACQUISITION REGULATIONS SYSTEM Administration 201.201-1 The two...

48 CFR 201.201-1 - The two councils.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 48 Federal Acquisition Regulations System 3 2013-10-01 2013-10-01 false The two councils. 201.201-1 Section 201.201-1 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE GENERAL FEDERAL ACQUISITION REGULATIONS SYSTEM Administration 201.201-1 The two...

48 CFR 201.201-1 - The two councils.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 48 Federal Acquisition Regulations System 3 2014-10-01 2014-10-01 false The two councils. 201.201-1 Section 201.201-1 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE GENERAL FEDERAL ACQUISITION REGULATIONS SYSTEM Administration 201.201-1 The two...

48 CFR 201.201-1 - The two councils.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 48 Federal Acquisition Regulations System 3 2011-10-01 2011-10-01 false The two councils. 201.201-1 Section 201.201-1 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE GENERAL FEDERAL ACQUISITION REGULATIONS SYSTEM Administration 201.201-1 The two...

48 CFR 201.201-1 - The two councils.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 48 Federal Acquisition Regulations System 3 2012-10-01 2012-10-01 false The two councils. 201.201-1 Section 201.201-1 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE GENERAL FEDERAL ACQUISITION REGULATIONS SYSTEM Administration 201.201-1 The two...

Stress Computed Tomography Myocardial Perfusion Imaging: A New Topic in Cardiology.

PubMed

Seitun, Sara; Castiglione Morelli, Margherita; Budaj, Irilda; Boccalini, Sara; Galletto Pregliasco, Athena; Valbusa, Alberto; Cademartiri, Filippo; Ferro, Carlo

2016-02-01

Since its introduction about 15 years ago, coronary computed tomography angiography has become today the most accurate clinical instrument for noninvasive assessment of coronary atherosclerosis. Important technical developments have led to a continuous stream of new clinical applications together with a significant reduction in radiation dose exposure. Latest generation computed tomography scanners (≥ 64 slices) allow the possibility of performing static or dynamic perfusion imaging during stress by using coronary vasodilator agents (adenosine, dipyridamole, or regadenoson), combining both functional and anatomical information in the same examination. In this article, the emerging role and state-of-the-art of myocardial computed tomography perfusion imaging are reviewed and are illustrated by clinical cases from our experience with a second-generation dual-source 128-slice scanner (Somatom Definition Flash, Siemens; Erlangen, Germany). Technical aspects, data analysis, diagnostic accuracy, radiation dose and future prospects are reviewed. Copyright © 2015 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

Normalization of reverse redistribution of thallium-201 with procainamide pretreatment in Wolff-Parkinson-White syndrome

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nii, T.; Nakashima, Y.; Nomoto, J.

1991-03-01

Stress thallium-201 myocardial perfusion imaging was performed in a patient with Wolff-Parkinson-White syndrome. Reverse redistribution phenomenon was observed in the absence of coronary artery disease. This seems to be the first report of normalization of this phenomenon in association with reversion of accessory pathway to normal atrioventricular conduction after pretreatment with procainamide.

AsS-Tl/sub 3/AsS/sub 4/ and AsS-Tl/sub 2/S systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vorob'ev, Yu.I.; Velikova, N.G.; Kirilenko, V.V.

1987-11-01

Using DTA and XPA as well as microstructural analysis and microhardness measurements, the AsS-Tl/sub 3/AsS/sub 4/ and AsS-Tl/sub 2/S phase diagrams are studied. Two new ternary compounds, Tl/sub 2/As/sub 3/S/sub 4/ and Tl/sub 2/As/sub 2/S/sub 3/, are revealed and their interplanar distances are calculated.

Additional diagnostic value of systolic dysfunction induced by dipyridamole stress cardiac magnetic resonance used in detecting coronary artery disease.

PubMed

Husser, Oliver; Bodí, Vicente; Sanchís, Juan; Mainar, Luis; Núñez, Julio; López-Lereu, María P; Monmeneu, José V; Ruiz, Vicente; Rumiz, Eva; Moratal, David; Chorro, Francisco J; Llácer, Angel

2009-04-01

Dipyridamole stress perfusion cardiovascular magnetic resonance (CMR) is used to detect coronary artery disease (CAD). However, few data are available on the diagnostic value of the systolic dysfunction induced by dipyridamole. This study investigated whether the induction of systolic dysfunction supplements the diagnostic information provided by perfusion imaging in the detection of CAD. Overall, 166 patients underwent dipyridamole CMR and quantitative coronary angiography, with CAD being defined as a stenosis > or =70%. Systolic dysfunction at rest, systolic dysfunction with dipyridamole, induced systolic dysfunction, and stress first-pass perfussion deficit (PD) and delayed enhancement were quantified. In the multivariate analysis, PD (hazard ratio [HR]=1.6; 95% confidence interval [CI], 1.33-1.91;P< .0001) and induced systolic dysfunction (OR=1.8; 95% CI, 1.18-2.28; P< .007) were independently associated with CAD and had a sensitivity and specificity of 92% and 62% and 43% and 96%, respectively. Patients were categorized as having no ischemia (Group 1), PD but no induced systolic dysfunction (Group 2), or induced systolic dysfunction irrespective of PD (Group 3). In Group 3, the prevalence of CAD was higher than in Group 1 or 2 (96% vs. 22% and 79%, respectively; P=.001) and the risk of CAD was two-fold higher than in Group 2 (OR=2.34; 95% CI, 1.07-5.13; P=.034). Compared with Group 2, more hypoperfused segments were observed in Group 3 (6.2+/-2.6 vs. 7.4+/-3.4; P=.044), and more diseased vessels (1.4+/-1.0 vs. 1.8+/-0.9; P=.036). Adding induced systolic dysfunction to perfusion and clinical data improved the multivariate model's C-statistic for predicting CAD (0.81 vs. 0.87; P=.02). Combining induced systolic dysfunction with perfusion imaging increases the diagnostic accuracy of detecting CAD and enables patients with severe ischemia and a high probability of CAD to be identified.

Advances in TlBr detector development

NASA Astrophysics Data System (ADS)

Hitomi, Keitaro; Shoji, Tadayoshi; Ishii, Keizo

2013-09-01

Thallium bromide (TlBr) is a promising compound semiconductor for fabrication of gamma-ray detectors. The attractive physical properties of TlBr lie in its high photon stopping power, high resistivity and good charge transport properties. Gamma-ray detectors fabricated from TlBr crystals have exhibited excellent spectroscopic performance. In this paper, advances in TlBr radiation detector development are reviewed with emphasis on crystal growth, detector fabrication, physical properties and detector performance.

Thallium (Tl) sorption onto illite and smectite: Implications for Tl mobility in the environment

NASA Astrophysics Data System (ADS)

Martin, Loïc A.; Wissocq, Aubéry; Benedetti, M. F.; Latrille, Christelle

2018-06-01

Clay minerals play a relevant role in the transport and fate of trace elements in the environment. Though illite has been referred as an important Thallium (Tl) bearing phase in soils, mechanisms and affinity of thallium for clay minerals remain poorly known. This study investigated the sorption behavior of thallium as Tl(I) onto illite and smectite, two clay minerals occurring mainly in soils and sediments. Different sorption experiments were carried out under various pH conditions and Tl concentrations, in competition with sodium and calcium at a constant ionic strength of 0.01 mol L-1. Our results showed that illite displayed more affinity than smectite for thallium. With illite, the distribution coefficients (Kd in L kg-1) varied between 102.75 ± 0.17 and 104.0 ± 0.17 in Na solutions versus between 102.25 ± 0.17 and 103.0 ± 0.17 in Ca solutions, depending on pH. With smectite, Kd (in L kg-1) ranged between 102.50 ± 0.16 and 103.20 ± 0.16 and between 101.25 ± 0.16 and 101.95 ± 0.16 in Na and Ca solutions, respectively. Sorption behavior was described with the Multi-Site Ion Exchanger model and selectivity coefficients with respect to protons were calculated for the first time. In all cases, independently of clay mineral and background electrolyte, low capacity but highly reactive sites were dominant in thallium uptake, highlighting Tl affinity for those sites. Moreover, the exchangeable and reversible interactions between Tl+ and clays reactive sites suggested that in changing conditions, thallium could be released in solution. The role of clay minerals in thallium environmental cycle is evident and confirmed illite to be a dominant Tl bearing phase, in some environment competing with manganese oxides. Compared to others Tl bearing mineral phases, clays are ranked as follows: MnO2 > illite > smectite ∼ ferrihydrite ≥ Al2O3 ∼ goethite > SiO2. Finally, over the three monovalent cations (Tl, Rb, Cs) Tl is the one less sorbed on illite independently of

Bone Regeneration in Critical Bone Defects Using Three-Dimensionally Printed β-Tricalcium Phosphate/Hydroxyapatite Scaffolds Is Enhanced by Coating Scaffolds with Either Dipyridamole or BMP-2

PubMed Central

Ishack, Stephanie; Mediero, Aranzazu; Wilder, Tuere; Ricci, John L.; Cronstein, Bruce N.

2017-01-01

Bone defects resulting from trauma or infection need timely and effective treatments to restore damaged bone. Using specialized three-dimensional (3-D) printing technology we have created custom 3-D scaffolds of hydroxyapatite (HA)/Beta-Tri-Calcium Phosphate (β-TCP) to promote bone repair. To further enhance bone regeneration we have coated the scaffolds with dipyridamole, an agent that increases local adenosine levels by blocking cellular uptake of adenosine. 15% HA:85% β-TCP scaffolds were designed using Robocad software, fabricated using a 3-D Robocasting system, and sintered at 1100°C for 4h. Scaffolds were coated with BMP-2 (200ng/ml), Dypiridamole 100µM or saline and implanted in C57B6 and adenosine A2A receptor knockout (A2AKO) mice with 3mm cranial critical bone defects for 2-8 weeks. Dipyridamole release from scaffold was assayed spectrophotometrically. MicroCT and histological analysis were performed. micro-computed tomography (microCT) showed significant bone formation and remodeling in HA/β-TCP- dipyridamole and HA/β-TCP -BMP-2 scaffolds when compared to scaffolds immersed in vehicle at 2, 4 and 8 weeks (n=5 per group; p≤ 0.05, p≤ 0.05 and p≤ 0.01, respectively). Histological analysis showed increased bone formation and a trend toward increased remodeling in HA/β-TCP- dipyridamole and HA/β-TCP-BMP-2 scaffolds. coating scaffolds with dipyridamole did not enhance bone regeneration in A2AKO mice. In conclusion, scaffolds printed with HA/β-TCP promote bone regeneration in critical bone defects and coating these scaffolds with agents that stimulate A2A receptors and growth factors can further enhance bone regeneration. These coated scaffolds may be very useful for treating critical bone defects due to trauma, infection or other causes. PMID:26513656

TlBr and TlBr xI 1-x crystals for γ-ray detectors

NASA Astrophysics Data System (ADS)

Churilov, Alexei V.; Ciampi, Guido; Kim, Hadong; Higgins, William M.; Cirignano, Leonard J.; Olschner, Fred; Biteman, Viktor; Minchello, Mark; Shah, Kanai S.

2010-04-01

TlBr and TlBr xI 1-x are wide bandgap semiconductor materials being investigated for applications in γ-ray spectroscopy. They have a good combination of density and atomic numbers, promising to make them very efficient detectors. Their low melting points and simple cubic and orthorhombic crystal structures are favorable for bulk crystal growth. However, these semiconductors need to be extremely pure to become useful as radiation detectors. Impurities can lead to charge trapping and scattering, reducing the charge transit lengths and limiting the detector thickness to <1 mm. Additional purification steps were implemented to improve the purity and mobility-lifetime product ( μτ) of electrons. Detector-grade TlBr with the electron μτ product of up to 6×10 -3 cm 2/V has been produced, which allowed operation of detectors up to 15 mm thickness. The ternary TlBr xI 1-x was investigated at different compositions to vary the bandgap and explore the effect of added TlI on the long term stability of detectors. The material analysis and detector characterization results are included.

Pressure and temperature dependences of the ionic conductivities of the thallous halidesTlCl, TlBr, and TlI

DOE Office of Scientific and Technical Information (OSTI.GOV)

Samara, G.A.

1981-01-15

Detailed studies of the pressure and temperature dependences of the ionic conductivities of TlCl and TlBr have allowed determination of the lattice volume relaxations and energies associated with the formation and motion of Schottky defects in these crystals. The volume relaxations deduced from the conductivity are found to be comparable in magnitude with values calculated from the strain energy model and a dynamical model. The association energy of Tl/sup +/ vacancies and divalent impurities was also determined for TlBr. A particularly important result is the finding that for these CsCl-type crystals the relaxation of the lattice associated with vacancy formationmore » is outward. Earlier studies on ionic crystals having the NaCl structure have yielded a similar result. This outward relaxation thus appears to be a general result for ionic crystals of both the NaCl and CsCl types (and possibly other ionic lattice types), in disagreement with earlier theoretical calculations which show that the relaxation should be inward for all models of ionic vacancies investigated. The conductivity of TlI was studied in both the (low temperature and pressure) orthorhombic phase as well as in the cubic CsCl-type phase. There is a large electronic contribution to the conductivity in the orthorhombic phase. An interesting result for all three materials is the observation in the cubic phase of a pressure-induced transition from ionic to electronic conduction. This is in qualitative agreement with what is known about the pressure dependences of the electronic structure of these materials.« less

Thallium myocardial perfusion scans for the assessment of right ventricular hypertrophy in patients with cystic fibrosis. A comparison with other noninvasive techniques

DOE Office of Scientific and Technical Information (OSTI.GOV)

Newth, C.J.; Corey, M.L.; Fowler, R.S.

1981-01-01

The incidence of right ventricular hypertrophy in 32 patients with cystic fibrosis was studied using thallium 201 (TI-201) myocardial perfusion scans, and compared with other noninvasive techniques including electrocardiography, vectorcardiography, and M-mode echocardiography. The patients (mean age, 17.3 yr; range, 7 to 33) had a wide range of clinical and pulmonary abnormalities (mean Shwachman-Kulczycki score, 66.6). In the total study group, TI-201 scans, like the vectorcardiograms and the M-mode echocardiograms, gave a surprisingly high proportion of positive predictions for right ventricular hypertrophy (RVH) (44%). The correlations with all other noninvasive methods were uniformly poor, so caution must be exercised inmore » using this technique to predict early RVH in order to follow the natural history of cor pulmonale in cystic fibrosis. At the time of the study, 6 patients had clinical evidence of right ventricular failure, and in this disease setting must have had RVH. In 3 patients, RVH was confirmed at autopsy, and it was successfully predicted by TI-201 scans in 5 of the 6 patients. The false negative scan may have been due to regional myocardial ischemia secondary to severe right ventricular failure. In contrast, the vectorcardiogram, using Fowler's new criteria, made a successful prediction of RVH in all 6 patients, and the electro cardiogram in only 3. Although the M-mode echocardiogram was abnormal in all patients, it would have predicted RVH (with increased right ventricular anterior wall thickness) in only 1 patient. We concluded that TI-201 myocardial perfusion cans are good at confirming RVH in cases with established right ventricular failure, but have no advantage over vectorcardiographic assessments, which are logistically easier to perform and carry no radiation risks.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boettcher, M.; Czernin, J.; Sun, K.

The {beta}{sub 1} receptor blockade reduces cardiac work and may thereby lower myocardial blood flow (MBF) at rest. The effect of {beta}{sub 1} receptor blockade on hyperemic MBF is unknown. To evaluate the effect of selective {beta}{sub 1} receptor blockade on MBF at rest and during dipyridamole induced hyperemia, 10 healthy volunteers (8 men, 2 women, mean age 24 {+-} 5 yr) were studied using {sup 13}N-ammonia PET (two-compartment model) under control conditions and again during metoprolol (50 mg orally 12 hr and 1 hr before the study). The resting rate pressure product (6628 {+-} 504 versus 5225 {+-} 807)more » and heart rate (63 {+-} 6-54 {plus_minus} 5 bpm) declined during metoprolol (p < 0.05). Similarly, heart rate and rate pressure product declined from the baseline dipyridamole study to dipyridamole plus metoprolol (p < 0.05). Resting MBF declined in proportion to cardiac work by approximately 20% from 0.61 {+-} 0.09-0.51 {+-} 0.10 ml/g/min (p < 0.05). In contrast, hyperemic MBF increased when metoprolol was added to dipyridamole (1.86 {plus_minus} 0.27 {+-} 0.45 ml/g/min; p<0.05). The decrease in resting MBF together with the increase in hyperemic MBF resulted in a significant increase in the myocardial flow reserve during metoprolol (3.14 {+-} 0.80-4.61 {+-} 0.68; p<0.01). The {beta}{sub 1} receptor blockade increases coronary vasodilatory capacity and myocardial flow reserve. However, the mechanisms accounting for this finding remain uncertain. 32 refs., 2 figs., 2 tabs.« less

Antiplatelet therapy with aspirin, clopidogrel, and dipyridamole versus clopidogrel alone or aspirin and dipyridamole in patients with acute cerebral ischaemia (TARDIS): a randomised, open-label, phase 3 superiority trial.

PubMed

Bath, Philip M; Woodhouse, Lisa J; Appleton, Jason P; Beridze, Maia; Christensen, Hanne; Dineen, Robert A; Duley, Lelia; England, Timothy J; Flaherty, Katie; Havard, Diane; Heptinstall, Stan; James, Marilyn; Krishnan, Kailash; Markus, Hugh S; Montgomery, Alan A; Pocock, Stuart J; Randall, Marc; Ranta, Annemarei; Robinson, Thompson G; Scutt, Polly; Venables, Graham S; Sprigg, Nikola

2018-03-03

Intensive antiplatelet therapy with three agents might be more effective than guideline treatment for preventing recurrent events in patients with acute cerebral ischaemia. We aimed to compare the safety and efficacy of intensive antiplatelet therapy (combined aspirin, clopidogrel, and dipyridamole) with that of guideline-based antiplatelet therapy. We did an international, prospective, randomised, open-label, blinded-endpoint trial in adult participants with ischaemic stroke or transient ischaemic attack (TIA) within 48 h of onset. Participants were assigned in a 1:1 ratio using computer randomisation to receive loading doses and then 30 days of intensive antiplatelet therapy (combined aspirin 75 mg, clopidogrel 75 mg, and dipyridamole 200 mg twice daily) or guideline-based therapy (comprising either clopidogrel alone or combined aspirin and dipyridamole). Randomisation was stratified by country and index event, and minimised with prognostic baseline factors, medication use, time to randomisation, stroke-related factors, and thrombolysis. The ordinal primary outcome was the combined incidence and severity of any recurrent stroke (ischaemic or haemorrhagic; assessed using the modified Rankin Scale) or TIA within 90 days, as assessed by central telephone follow-up with masking to treatment assignment, and analysed by intention to treat. This trial is registered with the ISRCTN registry, number ISRCTN47823388. 3096 participants (1556 in the intensive antiplatelet therapy group, 1540 in the guideline antiplatelet therapy group) were recruited from 106 hospitals in four countries between April 7, 2009, and March 18, 2016. The trial was stopped early on the recommendation of the data monitoring committee. The incidence and severity of recurrent stroke or TIA did not differ between intensive and guideline therapy (93 [6%] participants vs 105 [7%]; adjusted common odds ratio [cOR] 0·90, 95% CI 0·67-1·20, p=0·47). By contrast, intensive antiplatelet therapy was

External detection of regional myocardial metabolism with radioiodinated hexadecenoic acid in the dog heart.

PubMed

van der Wall, E E; Westera, G; den Hollander, W; Visser, F C

1981-04-01

In a previous study we have demonstrated that terminally iodinated hexadecenoic acid (131I-HA) and Thallium-201 (201T1) are comparable in myocardial uptake and distribution in the ischemic dog heart (Westera et al. 1980). In the present study the potential value of 131I-HA was proved in determining regional myocardial metabolism in 19 dog experiments. In ten dogs, 131I-HA was administered 5 min after occlusion of a coronary artery (group II), in six dogs after a 90 min occlusion period (group III). Three dogs served as controls (group I). The turnover rates (t 1/2) of 131I-HA were calculated from mono-exponential time-activity curves, obtained by external detection over ischemic and normally perfused areas during a 30 min period after IV injection of 0.7-1.5 mCi 131I-HA. The t 1/2 values in ischemic regions were found to be significantly longer (group II, 25.1 +/- 2.6 min; group III, 22.6 +/- 1.8 min) than in non-ischemic areas (group II, 12.5 +/- 1.8 min; group III, 14.2 +/- 1.4 min). The t 1/2 values in the control dogs (group I, 13.4 +/- 1.4 min) were not significantly different from the turnover rates in the non-ischemic areas of the occluded hearts. We conclude that the study of turnover rates of radioiodinated free fatty acids allows the determination of regional myocardial metabolism and offers a means to distinguish normally perfused from ischemic myocardial tissue.

Syntheses, crystal structures, and characterization of two new Tl+-Cu2+-Te6+ oxides: Tl4CuTeO6 and Tl6CuTe2O10

NASA Astrophysics Data System (ADS)

Yeon, Jeongho; Kim, Sang-Hwan; Green, Mark A.; Bhatti, Kanwal Preet; Leighton, C.; Shiv Halasyamani, P.

2012-12-01

Crystals and polycrystalline powders of two new oxide materials, Tl4CuTeO6 and Tl6CuTe2O10, have been synthesized by hydrothermal and solid-state methods. The materials were structurally characterized by single-crystal X-ray diffraction. Tl4CuTeO6 and Tl6CuTe2O10 exhibit one dimensional anionic slabs of [CuTeO6]4- and [CuTe2O10]6-, respectively. Common to both slabs is the occurrence of Cu2+O4 distorted squares and Te6+O6 octahedra. The slabs are separated by Tl+ cations. For Tl4CuTeO6, magnetic measurements indicate a maximum at ∼8 K in the temperature dependence of the susceptibility. Low temperature neutron diffraction data confirm no long-range magnetic ordering occurs and the susceptibility was adequately accounted for by fits to a Heisenberg alternating chain model. For Tl6CuTe2O10 on the other hand, magnetic measurements revealed paramagnetism with no evidence of long-range magnetic ordering. Infrared, UV-vis spectra, thermogravimetric, and differential thermal analyses are also reported. Crystal data: Tl4CuTeO6, Triclinic, space group P-1 (No. 2), a=5.8629(8) Å, b=8.7848(11) Å, c=9.2572(12) Å, α=66.0460(10), β=74.2010(10), γ=79.254(2), V=417.70(9) Å3, and Z=2; Tl6CuTe2O10, orthorhombic, space group Pnma (No. 62), a=10.8628(6) Å, b=11.4962(7) Å, c=10.7238(6) Å, V=1339.20(13) Å3, and Z=4.

[Hypertrophic cardiomyopathy showing no 123I-BMIPP myocardial accumulation with type I CD36 deficiency].

PubMed

Watanabe, K; Miyajima, S; Kusano, Y; Tanabe, N; Hirokawa, Y

1997-07-01

A 57 years old male consulted our hospital in complaining chest oppression and short of breath. Familial and dilated phase hypertrophic cardiomyopathy (HCM) was detected by ECG, echocardiography, left ventriculography and left ventricular endomyocardial biopsy. 201T1 SPECT showed regional increased accumulation in the ventricular septum, however, no myocardial accumulation of 123I-beta-methyl-p-iodophenylpentadecanoic acid (123I-BMIPP) was observed. We analyzed CD36 in this patient, and found he had type 1 CD36 deficiency. Myocardial uptake of long-chain fatty acids occurs via a specific transporter, which is homologous with human CD36. We hypothesize that CD36 deficiency, especially type 1 CD36 deficiency, might be one factor of no myocardial 123I-BMIPP uptake.

Identification of the ENT1 antagonists dipyridamole and dilazep as amplifiers of oncolytic herpes simplex virus-1 replication.

PubMed

Passer, Brent J; Cheema, Tooba; Zhou, Bingsen; Wakimoto, Hiroaki; Zaupa, Cecile; Razmjoo, Mani; Sarte, Jason; Wu, Shulin; Wu, Chin-lee; Noah, James W; Li, Qianjun; Buolamwini, John K; Yen, Yun; Rabkin, Samuel D; Martuza, Robert L

2010-05-15

Oncolytic herpes simplex virus-1 (oHSV) vectors selectively replicate in tumor cells, where they kill through oncolysis while sparing normal cells. One of the drawbacks of oHSV vectors is their limited replication and spread to neighboring cancer cells. Here, we report the outcome of a high-throughput chemical library screen to identify small-molecule compounds that augment the replication of oHSV G47Delta. Of the 2,640-screened bioactives, 6 compounds were identified and subsequently validated for enhanced G47Delta replication. Two of these compounds, dipyridamole and dilazep, interfered with nucleotide metabolism by potently and directly inhibiting the equilibrative nucleoside transporter-1 (ENT1). Replicative amplification promoted by dipyridamole and dilazep were dependent on HSV mutations in ICP6, the large subunit of ribonucleotide reductase. Our results indicate that ENT1 antagonists augment oHSV replication in tumor cells by increasing cellular ribonucleoside activity. (c)2010 AACR.

Positron Emission Tomography for the Assessment of Myocardial Viability

PubMed Central

2010-01-01

, harmonic imaging, and power doppler imaging may help to improve the diagnostic accuracy of echocardiographic assessment of myocardial viability. Stress Echocardiography with Contrast Intravenous contrast agents, which are high molecular weight inert gas microbubbles that act like red blood cells in the vascular space, can be used during echocardiography to assess myocardial viability. These agents allow for the assessment of myocardial blood flow (perfusion) and contractile function (as described above), as well as the simultaneous assessment of perfusion to make it possible to distinguish between stunned and hibernating myocardium. SPECT SPECT can be performed using thallium-201 (Tl-201), a potassium analogue, or technetium-99 m labelled tracers. When Tl-201 is injected intravenously into a patient, it is taken up by the myocardial cells through regional perfusion, and Tl-201 is retained in the cell due to sodium/potassium ATPase pumps in the myocyte membrane. The stress-redistribution-reinjection protocol involves three sets of images. The first two image sets (taken immediately after stress and then three to four hours after stress) identify perfusion defects that may represent scar tissue or viable tissue that is severely hypoperfused. The third set of images is taken a few minutes after the re-injection of Tl-201 and after the second set of images is completed. These re-injection images identify viable tissue if the defects exhibit significant fill-in (> 10% increase in tracer uptake) on the re-injection images. The other common Tl-201 viability imaging protocol, rest-redistribution, involves SPECT imaging performed at rest five minutes after Tl-201 is injected and again three to four hours later. Viable tissue is identified if the delayed images exhibit significant fill-in of defects identified in the initial scans (> 10% increase in uptake) or if defects are fixed but the tracer activity is greater than 50%. There are two technetium-99 m tracers: sestamibi (MIBI

Bone regeneration in critical bone defects using three-dimensionally printed β-tricalcium phosphate/hydroxyapatite scaffolds is enhanced by coating scaffolds with either dipyridamole or BMP-2.

PubMed

Ishack, Stephanie; Mediero, Aranzazu; Wilder, Tuere; Ricci, John L; Cronstein, Bruce N

2017-02-01

Bone defects resulting from trauma or infection need timely and effective treatments to restore damaged bone. Using specialized three-dimensional (3D) printing technology we have created custom 3D scaffolds of hydroxyapatite (HA)/beta-tri-calcium phosphate (β-TCP) to promote bone repair. To further enhance bone regeneration we have coated the scaffolds with dipyridamole, an agent that increases local adenosine levels by blocking cellular uptake of adenosine. Nearly 15% HA:85% β-TCP scaffolds were designed using Robocad software, fabricated using a 3D Robocasting system, and sintered at 1100°C for 4 h. Scaffolds were coated with BMP-2 (200 ng mL -1 ), dypiridamole 100 µM or saline and implanted in C57B6 and adenosine A2A receptor knockout (A2AKO) mice with 3 mm cranial critical bone defects for 2-8 weeks. Dipyridamole release from scaffold was assayed spectrophotometrically. MicroCT and histological analysis were performed. Micro-computed tomography (microCT) showed significant bone formation and remodeling in HA/β-TCP-dipyridamole and HA/β-TCP-BMP-2 scaffolds when compared to scaffolds immersed in vehicle at 2, 4, and 8 weeks (n = 5 per group; p ≤ 0.05, p ≤ 0.05, and p ≤ 0.01, respectively). Histological analysis showed increased bone formation and a trend toward increased remodeling in HA/β-TCP- dipyridamole and HA/β-TCP-BMP-2 scaffolds. Coating scaffolds with dipyridamole did not enhance bone regeneration in A2AKO mice. In conclusion, scaffolds printed with HA/β-TCP promote bone regeneration in critical bone defects and coating these scaffolds with agents that stimulate A2A receptors and growth factors can further enhance bone regeneration. These coated scaffolds may be very useful for treating critical bone defects due to trauma, infection or other causes. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 366-375, 2017. © 2015 Wiley Periodicals, Inc.

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. Copyright © 2014 Elsevier B.V. All rights reserved.

Electromodulation spectroscopy of excitons in simple cubic TlCl and TlBr

DOE Office of Scientific and Technical Information (OSTI.GOV)

McClelland, J.F.; Lynch, D.W.

1979-03-15

Transmission and electromodulated transmission spectra have been measured in the direct Wannier exciton region for TlCl and TlBr. The spectra were obtained at a sample temperature between 5 and 6 K for a range of applied electric fields. The data have been reduced to obtain the electric-field-induced changes in the dielectric function and compared in detail to the calculations of Blossey. The experimental results support the trends predicted by the calculations.

[Tl(III)(dota)](-): An Extraordinarily Robust Macrocyclic Complex.

PubMed

Fodor, Tamás; Bányai, István; Bényei, Attila; Platas-Iglesias, Carlos; Purgel, Mihály; Horváth, Gábor L; Zékány, László; Tircsó, Gyula; Tóth, Imre

2015-06-01

The X-ray structure of {C(NH2)3}[Tl(dota)]·H2O shows that the Tl(3+) ion is deeply buried in the macrocyclic cavity of the dota(4-) ligand (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate) with average Tl-N and Tl-O distances of 2.464 and 2.365 Å, respectively. The metal ion is directly coordinated to the eight donor atoms of the ligand, which results in a twisted square antiprismatic (TSAP') coordination around Tl(3+). A multinuclear (1)H, (13)C, and (205)Tl NMR study combined with DFT calculations confirmed the TSAP' structure of the complex in aqueous solution, which exists as the Λ(λλλλ)/Δ(δδδδ) enantiomeric pair. (205)Tl NMR spectroscopy allowed the protonation constant associated with the protonation of the complex according to [Tl(dota)](-) + H(+) ⇆ [Tl(Hdota)] to be determined, which turned out to be pK(H)Tl(dota) = 1.4 ± 0.1. [Tl(dota)](-) does not react with Br(-), even when using an excess of the anion, but it forms a weak mixed complex with cyanide, [Tl(dota)](-) + CN(-) ⇆ [Tl(dota)(CN)](2-), with an equilibrium constant of Kmix = 6.0 ± 0.8. The dissociation of the [Tl(dota)](-) complex was determined by UV-vis spectrophotometry under acidic conditions using a large excess of Br(-), and it was found to follow proton-assisted kinetics and to take place very slowly (∼10 days), even in 1 M HClO4, with the estimated half-life of the process being in the 10(9) h range at neutral pH. The solution dynamics of [Tl(dota)](-) were investigated using (13)C NMR spectroscopy and DFT calculations. The (13)C NMR spectra recorded at low temperature (272 K) point to C4 symmetry of the complex in solution, which averages to C4v as the temperature increases. This dynamic behavior was attributed to the Λ(λλλλ) ↔ Δ(δδδδ) enantiomerization process, which involves both the inversion of the macrocyclic unit and the rotation of the pendant arms. According to our calculations, the arm-rotation process limits the Λ(λλλλ) ↔ �

Aspirin plus dipyridamole has the highest surface under the cumulative ranking curves (SUCRA) values in terms of mortality, intracranial hemorrhage, and adverse event rate among 7 drug therapies in the treatment of cerebral infarction.

PubMed

Zhang, Jian-Jun; Liu, Xin

2018-03-01

The standardization for the clinical use of drug therapy for cerebral infarction (CI) has not yet determined in some aspects. In this paper, we discussed the efficacies of different drug therapies (aspirin, aspirin plus dipyridamole, aspirin plus clopidogrel, aspirin plus warfarin, cilostazol, warfarin, and ticlopidine) for CI. We searched databases of PubMed and Cochrane Library from the inception to April, 2017, randomized controlled trials (RCTs) met the inclusion and exclusion criteria were enrolled in this study. The network meta-analysis integrated evidences of direct and indirect comparisons to assess odd ratios (OR) and surface under the cumulative ranking curves (SUCRA) value. Thirteen eligible RCTs including 7 drug therapies were included into this network meta-analysis. The network meta-analysis results showed that CI patients who received aspirin plus dipyridamole presented lower mortality when compared with those received aspirin plus clopidogrel (OR = 0.46, 95% CI = 0.18-0.99), indicating aspirin plus dipyridamole therapy had better efficacy for CI. As for intracranial hemorrhage (ICH), stroke recurrence, and adverse event (AE) rate, there were no significant differences of efficacy among 7 drug therapies. Besides, SUCRA values demonstrated that in the 7 drug therapies, aspirin plus dipyridamole therapy was more effective than others (mortality: 80.67%; ICH: 76.6%; AE rate: 90.2%). Our findings revealed that aspirin plus dipyridamole therapy might be the optimum one for patients with CI, which could help to improve the survival of CI patients.

Optimal formation and enhanced superconductivity of Tl-1212 phase (Tl0.6Pb0.4)(Ba,Sr)CaCu2O7

NASA Astrophysics Data System (ADS)

Ranjbar, M. G.; Ghoranneviss, Mahmood; Abd-Shukor, R.

2018-06-01

The effect of heating temperature on the formation of Tl-1212 phase with nominal starting composition (Tl0.6Pb0.4)(Ba,Sr)CaCu2O7 (Tl-1212) is reported. The Ba-bearing Tl-1212 phase is normally prepared at around 900 °C while with Sr-bearing sample is prepared at a much higher temperature of around 1000 °C. This work was conducted to determine the optimal temperature to synthesis the Tl-1212 phase when the sample contains Ba and Sr with 1:1 ratio. (Tl0.6Pb0.4)(Ba,Sr)CaCu2O7 samples were prepared using the solid-state reaction method via the precursor route. In the final preparation stage, the samples were heated at 850, 870, 900, 920, 950, 970 and 1000 °C in oxygen flow. X-Ray diffraction patterns showed that most samples consisted of a mixed (Tl0.6Pb0.4)(Ba,Sr)Ca2Cu3O9 (Tl-1223) and Tl-1212 phase except for the sample heated at 970 °C which showed a single Tl-1212 phase and the sample heated at 850 °C which showed the Tl-1223 phase. The transition temperature measured by four-probe method showed that the sample heated at 970 °C exhibited the highest onset temperature of 118 K and zero-resistance temperature of 100 K. This transition temperature is higher than the usually reported value for the Tl-1212 phase. AC susceptibility measurements also showed the 970 °C heated sample with the highest transition temperature T c χ' = 109 K. The interplay of ionic radius (Ba2+ and Sr2+) decreases of the unit cell volume and changes in the internal lattice strain enhanced the transition temperature and the formation of the Tl-1212 phase.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carvalho, P.A.; Garada, B.M.; Loeffler, J.S.

To verify the utility of a volumetric estimation of Tl-201 uptake in the context of possible astrocytoma recurrence after surgery, radiotherapy plus stereotactic boost (radiosurgery/brachitherapy), we analyzed sequential Tl-201/Tc99m-HMPAO brain SPECT studies of 28 patients (18 m/10 f). These were categorized as having tumor mass recurrence (TM), infiltrating tumor cells but no definite tumor mass (IT), or radiation changes and necrosis (RCN) after stereotactic biopsy and/or craniotomy. SPECT studies were obtained with a high-resolution dedicated gamma camera (CERASPECT, Digital Scinitgraphics, Inc.) and image acquisition was performed after intravenous Tl-201 (18.5 MBq) and Tc-99m HMPAO (740 MBq). In order to includemore » relevant information about tumor burden, a volumetric index of Tl-201 uptake was expressed in cm{sup 3} related to voxel size (4.6 x 10{sup -3} cc) within an elliptical ROI that included the tumor area. Only voxels with a threshold {ge} 2 in relation to the average scalp Tl-201 uptake were included and this total number of voxels expressed in cc was compared to previously established maximal tumor/scalp Tl-201 uptake ratios (T/S) and histopathology. Results are presented as the median (min-max) and differences were considered significant for p<0.05. Differences were significant between all groups for both ratios and volume indices and correlation between the two variables was 0.90. In conclusion, the volumetric index of Tl-201 is similar to the maximal Tl-201 T/S ratios in discriminating tumor recurrence and radiation necrosis, suggesting a future role for the volumetric index estimation in the evaluation of treatment efficacy and patient follow-up.« less

Troublesome Knowledge of SoTL

ERIC Educational Resources Information Center

Manarin, Karen; Abrahamson, Earle

2016-01-01

This study explores the Scholarship of Teaching and Learning (SoTL) as a form of troublesome knowledge (Perkins 1999) that continues to trouble its practitioners. Forty-eight higher education professionals from six countries described their understanding of SoTL in an online survey; ten individuals participated in follow-up interviews to consider…

Principles of Good Practice in SoTL

ERIC Educational Resources Information Center

Felten, Peter

2013-01-01

For the Scholarship of Teaching and Learning (SoTL) to be understood as significant intellectual work in the academy, SoTL practitioners need to identify shared principles of good practice. While honoring the diversity of SoTL in its many forms across the globe, such principles can serve as a heuristic for assessing work in our field. These…

Thermoluminescence (TL) properties and x-ray diffraction (XRD) analysis of high purity CaSO4:Dy TL material

NASA Astrophysics Data System (ADS)

Kamarudin, Nadira; Abdullah, Wan Saffiey Wan; Hamid, Muhammad Azmi Abdul; Dollah, Mohd Taufik

2014-09-01

This paper presents the characterization and TL properties of dysprosium (Dy) doped calcium sulfate (CaSO4) TL material produced by co-precipitation technique with 0.5mol% concentration of dopant. The morphology of the produced TL material was studied using scanning electron microscope (SEM) and the micrograph shows that rectangular parallelepiped shaped crystal with the average of 150 μm in length were produced. The crystallinity of the produced powder was studied using x-ray powder diffraction (XRD). The XRD spectra show that the TL material produced is high purity anhydrite CaSO4 with average crystallite size of 74 nm with orthorhombic crystal system. The TL behavior of produced CaSO4:Dy was studied using a TLD reader after exposure to gamma ray by Co60 source with the doses of 1,5 and 10 Gy. The glow curve shows linear response with glow peak around 230°C which is desired development in the field of radiation dosimetry.

Recent Development of TlBr Gamma-Ray Detectors

NASA Astrophysics Data System (ADS)

Hitomi, Keitaro; Tada, Tsutomu; Kim, Seong-Yun; Wu, Yan; Tanaka, Tomonobu; Shoji, Tadayoshi; Yamazaki, Hiromichi; Ishii, Keizo

2011-08-01

Planar detectors, strip detectors, and double-sided strip detectors were fabricated from TlBr crystals grown by the traveling molten zone method using zone-purified material. The detector performance including the leakage current, energy resolutions, and timing performance were evaluated in order to assess the capability of the detectors for PET and SPECT applications. The TlBr detectors exhibited excellent spectroscopic performance at room temperature. An energy resolution of 3.4% FWHM at 511 keV was obtained from a TlBr planar detector 1 mm thick. A TlBr strip detector 1 mm thick with four anode strip electrodes exhibited almost uniform detector performance over the strips with the average energy resolution of 4.4% FWHM at 511 keV. A TlBr double-sided strip detector exhibited an energy resolution of 6.3% FWHM for 122 keV gamma-rays. Coincidence timing spectra between a TlBr planar detector and a BaF2 scintillation detector were recorded at room temperature. Timing resolutions of 14 ns and 24 ns were obtained from TlBr detectors 0.5 mm and 1 mm thick, respectively. By cooling the detector to 0° C, an improved timing resolution of 12 ns was obtained from a TlBr detector 1 mm thick.

Use of myocardial perfusion imaging and estimation of associated radiation doses in Germany from 2005 to 2012.

PubMed

Lindner, O; Bengel, F M; Hacker, M; Schäfer, W; Burchert, W

2014-05-01

For several years the Working Group Cardiovascular Nuclear Medicine of the German Society of Nuclear Medicine has been performing a regular survey to obtain information on technique, utilization and development of myocardial perfusion scintigraphy (MPS). Currently, data of six surveys from 2005 to 2012 are available. The aim of this paper is to deliver a general and comprehensive overview of all surveys documenting the course of patient doses over time and the development of the method. A one-page questionnaire with number of MPS patients, number of stress and rest MPS, referral structure and several technical issues was sent to all centres performing MPS in Germany and evaluated. With the data on protocol utilization, effective MPS patient doses were estimated. MPS per million population (pmp) varied between 2,380 and 2,770. In 2012, MPS pmp showed a slight increase for the first time. From 2005 to 2009 the angiography to MPS ratio increased from 3.4 to 4.4, and the revascularization to MPS ratio decreased from 0.66 to 0.53. In 2012, both indices demonstrated an opposite trend for the first time (4.1 and 0.55). A total of 108 centres participated in all surveys. They showed an increase in MPS patients of 4.0 % over the reporting period. In 2012, more than 50 % of the centres experienced no change or an increase in MPS numbers. The leading single competitor was MRI, followed by angiography and stress echocardiography. (201)Tl studies have decreased since 2005 from 20 to 5 %. (99m)Tc MPS studies showed a mild increase in 2-day protocols. In 2012, the average effective dose per patient was estimated at 7.4 mSv. Due to the decreasing use of (201)Tl, a mild decline over the observation period can be documented. Dynamic exercise stress was the most common stress test and adenosine the leading pharmacological stress agent, with a growing percentage. In 2012, the regadenoson percentage was 9 %. Gated single photon emission computed tomography (SPECT) noted an increasing

Analytical Method Development and Validation for the Quantification of Acetone and Isopropyl Alcohol in the Tartaric Acid Base Pellets of Dipyridamole Modified Release Capsules by Using Headspace Gas Chromatographic Technique

PubMed Central

2018-01-01

A simple, sensitive, accurate, robust headspace gas chromatographic method was developed for the quantitative determination of acetone and isopropyl alcohol in tartaric acid-based pellets of dipyridamole modified release capsules. The residual solvents acetone and isopropyl alcohol were used in the manufacturing process of the tartaric acid-based pellets of dipyridamole modified release capsules by considering the solubility of the dipyridamole and excipients in the different manufacturing stages. The method was developed and optimized by using fused silica DB-624 (30 m × 0.32 mm × 1.8 µm) column with the flame ionization detector. The method validation was carried out with regard to the guidelines for validation of analytical procedures Q2 demanded by the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH). All the validation characteristics were meeting the acceptance criteria. Hence, the developed and validated method can be applied for the intended routine analysis. PMID:29686931

Analytical Method Development and Validation for the Quantification of Acetone and Isopropyl Alcohol in the Tartaric Acid Base Pellets of Dipyridamole Modified Release Capsules by Using Headspace Gas Chromatographic Technique.

PubMed

Valavala, Sriram; Seelam, Nareshvarma; Tondepu, Subbaiah; Jagarlapudi, V Shanmukha Kumar; Sundarmurthy, Vivekanandan

2018-01-01

A simple, sensitive, accurate, robust headspace gas chromatographic method was developed for the quantitative determination of acetone and isopropyl alcohol in tartaric acid-based pellets of dipyridamole modified release capsules. The residual solvents acetone and isopropyl alcohol were used in the manufacturing process of the tartaric acid-based pellets of dipyridamole modified release capsules by considering the solubility of the dipyridamole and excipients in the different manufacturing stages. The method was developed and optimized by using fused silica DB-624 (30 m × 0.32 mm × 1.8  µ m) column with the flame ionization detector. The method validation was carried out with regard to the guidelines for validation of analytical procedures Q2 demanded by the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH). All the validation characteristics were meeting the acceptance criteria. Hence, the developed and validated method can be applied for the intended routine analysis.

Tl And Osl Response Of Turquoise For Dosimetric Application

NASA Astrophysics Data System (ADS)

Subedi, B.; Afouxenidis, D.; Polymeris, G. S.; Tsirlignanis, N.; Paraskevopoulos, K. M.; Kitis, G.

Turquoise is one of the amongst first gem stones used in jewelry and possessing cultural value since 2000 BC (at least). This work attempts characterize this stone scientifically using both thermally (TL) and optically stimulated luminescence (OSL) techniques. The experimental investigation included 1) the study of the natural TL and OSL signals, 2) the reproducibility of TL sensitivity over repeated irradiation and TL readout cycles, 3) dependence of sensitivity on annealing temperatures and 4) the TL and OSL dose response curves. The potential use of the TL and OSL techniques in determination of provenance, accidental dosimetry and probably to authenticity and dating purposes are then discussed.

Navigating the IRB: The Ethics of SoTL

ERIC Educational Resources Information Center

Martin, Ryan C.

2013-01-01

This chapter discusses Institutional Review Boards (IRBs) as they apply to the SoTL. Specifically, it describes when SoTL projects must receive IRB approval, why they must get IRB approval, the review process, and some special issues of concern with regard to SoTL.

41 CFR 50-201.201 - Breach of stipulations.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 41 Public Contracts and Property Management 1 2010-07-01 2010-07-01 true Breach of stipulations... Public Contracts PUBLIC CONTRACTS, DEPARTMENT OF LABOR 201-GENERAL REGULATIONS § 50-201.201 Breach of... determination of a breach of stipulations is made, the Secretary of Labor will furnish to the contracting agency...

Nuclear cardiology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Willerson, J.T.

1979-01-01

Nuclear Cardiology is a well-written, concise compendium of chapters that covers a wide range of topics in nuclear cardiology. Each chapter has been contributed by one or more recognized experts in the field, and the work is thoroughly referened. The physics and physiology of nuclear cardiology, myocardial imaging with /sup 201/Tl and /sup 99m/Tc pyrophosphate, left ventricular and right ventricular function, measurement of coronary blood flow with /sup 133/Xe, and microspheres are discussed, and there are chapters on metabolic imaging with positron emitters and on transmission computerized tomography of the heart.

Area at risk can be assessed by iodine-123-meta-iodobenzylguanidine single-photon emission computed tomography after myocardial infarction: a prospective study.

PubMed

Hedon, Christophe; Huet, Fabien; Ben Bouallegue, Fayçal; Vernhet, Hélène; Macia, Jean-Christophe; Cung, Thien-Tri; Leclercq, Florence; Cade, Stéphane; Cransac, Frédéric; Lattuca, Benoit; Vandenberghe, D'Arcy; Bourdon, Aurélie; Benkiran, Meriem; Vauchot, Fabien; Gervasoni, Richard; D'estanque, Emmanuel; Mariano-Goulart, Denis; Roubille, François

2018-02-01

Myocardial salvage is an important surrogate endpoint to estimate the impact of treatments in patients with ST-segment elevation myocardial infarction (STEMI). The aim of this study was to evaluate the correlation between cardiac sympathetic denervation area assessed by single-photon emission computed tomography (SPECT) using iodine-123-meta-iodobenzylguanidine (I-MIBG) and myocardial area at risk (AAR) assessed by cardiac magnetic resonance (CMR) (gold standard). A total of 35 postprimary reperfusion STEMI patients were enrolled prospectively to undergo SPECT using I-MIBG (evaluates cardiac sympathetic denervation) and thallium-201 (evaluates myocardial necrosis), and to undergo CMR imaging using T2-weighted spin-echo turbo inversion recovery for AAR and postgadolinium T1-weighted phase sensitive inversion recovery for scar assessment. I-MIBG imaging showed a wider denervated area (51.1±16.0% of left ventricular area) in comparison with the necrosis area on thallium-201 imaging (16.1±14.4% of left ventricular area, P<0.0001). CMR and SPECT provided similar evaluation of the transmural necrosis (P=0.10) with a good correlation (R=0.86, P<0.0001). AAR on CMR was not different compared with the denervated area (P=0.23) and was adequately correlated (R=0.56, P=0.0002). Myocardial salvage evaluated by SPECT imaging (mismatch denervated but viable myocardium) was significantly higher than by CMR (P=0.02). In patients with STEMI, I-MIBG SPECT, assessing cardiac sympathetic denervation may precisely evaluate the AAR, providing an alternative to CMR for AAR assessment.

Coronary microvascular function and myocardial fibrosis in women with angina pectoris and no obstructive coronary artery disease: the iPOWER study.

PubMed

Mygind, Naja Dam; Michelsen, Marie Mide; Pena, Adam; Qayyum, Abbas Ali; Frestad, Daria; Christensen, Thomas Emil; Ghotbi, Adam Ali; Dose, Nynne; Faber, Rebekka; Vejlstrup, Niels; Hasbak, Philip; Kjaer, Andreas; Prescott, Eva; Kastrup, Jens

2016-11-04

Even in absence of obstructive coronary artery disease women with angina pectoris have a poor prognosis possibly due to coronary microvascular disease. Coronary microvascular disease can be assessed by transthoracic Doppler echocardiography measuring coronary flow velocity reserve (CFVR) and by positron emission tomography measuring myocardial blood flow reserve (MBFR). Diffuse myocardial fibrosis can be assessed by cardiovascular magnetic resonance (CMR) T1 mapping. We hypothesized that coronary microvascular disease is associated with diffuse myocardial fibrosis. Women with angina, a clinically indicated coronary angiogram with <50 % stenosis and no diabetes were included. CFVR was measured using dipyridamole (0.84 mg/kg) and MBFR using adenosine (0.84 mg/kg). Focal fibrosis was assessed by 1.5 T CMR late gadolinium enhancement (0.1 mmol/kg) and diffuse myocardial fibrosis by T1 mapping using a modified Look-Locker pulse sequence measuring T1 and extracellular volume fraction (ECV). CFVR and CMR were performed in 64 women, mean (SD) age 62.5 (8.3) years. MBFR was performed in a subgroup of 54 (84 %) of these women. Mean native T1 was 1023 (86) and ECV (%) was 33.7 (3.5); none had focal fibrosis. Median (IQR) CFVR was 2.3 (1.9; 2.7), 23 (36 %) had CFVR < 2 indicating coronary microvascular disease, and median MBFR was 2.7 (2.2; 3.0) and 19 (35 %) had a MBFR value below 2.5. No significant correlations were found between CFVR and ECV or native T1 (R 2  = 0.02; p = 0.27 and R 2  = 0.004; p = 0.61, respectively). There were also no correlations between MBFR and ECV or native T1 (R 2  = 0.1; p = 0.13 and R 2  = 0.004, p = 0.64, respectively). CFVR and MBFR were correlated to hypertension and heart rate. In women with angina and no obstructive coronary artery disease we found no association between measures of coronary microvascular disease and myocardial fibrosis, suggesting that myocardial ischemia induced by coronary

First-Principles Study of Impurities in TlBr

DOE Office of Scientific and Technical Information (OSTI.GOV)

Du, Mao-Hua

2012-01-01

TlBr is a promising semiconductor material for room-temperature radiation detection. Material purification has been the driver for the recent improvement in the TlBr detector performance, mainly reflected by the significant increase in the carrier mobility-lifetime product. This suggests that impurities have significant impact on the carrier transport in TlBr. In this paper, first-principles calculations are used to study the properties of a number of commonly observed impurities in TlBr. The impurity-induced gap states are presented and their effects on the carrier trapping are discussed.

First-principles study of impurities in TlBr

NASA Astrophysics Data System (ADS)

Du, Mao-Hua

2012-04-01

TlBr is a promising semiconductor material for room-temperature radiation detection. Material purification has been the driver for the recent improvement in the TlBr detector performance, mainly reflected by the significant increase in the carrier mobility-lifetime product. This suggests that impurities have significant impact on the carrier transport in TlBr. In this paper, first-principles calculations are used to study the properties of a number of commonly observed impurities in TlBr. The impurity-induced gap states are presented and their effects on the carrier trapping are discussed.

Thermoluminescence (TL) properties and x-ray diffraction (XRD) analysis of high purity CaSO{sub 4}:Dy TL material

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kamarudin, Nadira; Abdullah, Wan Saffiey Wan; Dollah, Mohd Taufik

2014-09-03

This paper presents the characterization and TL properties of dysprosium (Dy) doped calcium sulfate (CaSO{sub 4}) TL material produced by co-precipitation technique with 0.5mol% concentration of dopant. The morphology of the produced TL material was studied using scanning electron microscope (SEM) and the micrograph shows that rectangular parallelepiped shaped crystal with the average of 150 μm in length were produced. The crystallinity of the produced powder was studied using x-ray powder diffraction (XRD). The XRD spectra show that the TL material produced is high purity anhydrite CaSO{sub 4} with average crystallite size of 74 nm with orthorhombic crystal system. Themore » TL behavior of produced CaSO{sub 4}:Dy was studied using a TLD reader after exposure to gamma ray by Co{sup 60} source with the doses of 1,5 and 10 Gy. The glow curve shows linear response with glow peak around 230°C which is desired development in the field of radiation dosimetry.« less

Electro-migration of impurities in TlBr

NASA Astrophysics Data System (ADS)

Kim, Ki Hyun; Kim, Eunlim; Kim, H.; Tappero, R.; Bolotnikov, A. E.; Camarda, G. S.; Hossain, A.; Cirignano, L.; James, R. B.

2013-10-01

We observed the electro-migration of Cu, Ag, and Au impurities that exist in positive-ion states in TlBr detectors under electric field strengths typically used for device operation. The migration occurred predominantly through bulk- and specific-channels, which are presumed to be a network of grain and sub-grain boundaries. The electro-migration velocity of Cu, Ag, and Au in TlBr is about 4-8 × 10-8 cm/s at room temperature under an electric field of 500-800 V/mm. The instability and polarization effects of TlBr detectors might well be correlated with the electro-migration of residual impurities in TlBr, which alters the internal electric field over time. The effect may also have been due to migration of the electrode material itself, which would allow for the possibility of a better choice for contact material and for depositing an effective diffusion barrier. From our findings, we suggest that applying our electro-migration technique for purifying material is a promising new way to remove electrically active metallic impurities in TlBr crystals, as well as other materials.

Interaction of Tl +3 with mononucleotides: metal ion binding and sugar conformation

NASA Astrophysics Data System (ADS)

Nafisi, Sh.; Mohajerani, N.; Hadjiakhoondi, A.; Monajemi, M.; Garib, F.

2001-05-01

The interaction of Tl 3+ with sodium salts of adenosine-5'-monophosphate (5'-AMP), guanosine-5'-monophosphate (5'-GMP), cytidine-5'-monophosphate (5'-CMP), thymidine 5'-monophosphate (5'-dTMP) in ratios 1 and 2 have been studied in neutral pH. The solid complexes were isolated and characterized by Fourier transform infrared (FTIR) and 1H NMR spectroscopy. In the Tl 2(AMP) 3, Tl 3+ binds directly to N-7 and indirectly to the N-1 position of the pyrimidine ring and phosphate group with sugar moiety in C2'-endoanti. The crystalline salt of Tl 2(GMP) 3 show direct Tl-N-7 and Tl-PO 3(inner-sphere) binding. The conformation of ribose moiety in Tl 2(GMP) 3 is C3'-endoanti. In the Tl 2(CMP) 3, Tl 3+ bind directly to N-3 and PO32- (inner-sphere). The conformation of ribose moiety in Tl 2(CMP) 3 is C2'-endoanti. In the Tl 2(dTMP) 3, Tl 3+ bind indirectly to carbonyl group. The sugar moiety in Tl 2(dTMP) 3 is C3'-endoanti.

Ab initio calculations of the electron spectrum and density of states of TlFeS{sub 2} and TlFeSe{sub 2} crystals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ismayilova, N. A., E-mail: ismayilova-narmin-84@mail.ru; Orudjev, H. S.; Jabarov, S. H.

2017-04-15

The results of ab initio calculations of the electron spectrum of TlFeS{sub 2} and TlFeSe{sub 2} crystals in the antiferromagnetic phase are reported. Calculations are carried out in the context of the density functional theory. The origin of the bands of s, p, and d electron states of Tl, Fe, S, and Se atoms is studied. It is established that, in the antiferromagnetic phase, the crystals possess semiconductor properties. The band gaps are found to be 0.05 and 0.34 eV for TlFeS{sub 2} and TlFeSe{sub 2} crystals, respectively.

High-nuclearity Pt-Tl-Fe complexes: structural, electrochemistry, and spectroelectrochemistry studies.

PubMed

Díez, Alvaro; Fernández, Julio; Lalinde, Elena; Moreno, M Teresa; Sánchez, Sergio

2010-12-20

A series of heteropolynuclear Pt-Tl-Fe complexes have been synthesized and structurally characterized. The final structures strongly depend on the geometry of the precursor and the Pt/Tl ratio used. Thus, the anionic heteroleptic cis-configured [cis-Pt(C(6)F(5))(2)(C≡CFc)(2)](2-) and [Pt(bzq)(C≡CFc)(2)](-) (Fc = ferrocenyl) complexes react with Tl(+) to form discrete octanuclear (PPh(3)Me)(2)[{trans,cis,cis-PtTl(C(6)F(5))(2)(C≡CFc)(2)}(2)] (1), [PtTl(bzq)(C≡CFc)(2)](2) (5; bzq = benzoquinolate), and decanuclear [trans,cis,cis-PtTl(2)(C(6)F(5))(2)(C≡CFc)(2)](2) (3) derivatives, stabilized by both Pt(II)···Tl(I) and Tl(I)···η(2)(alkynyl) bonds. By contrast, Q(2)[trans-Pt(C(6)F(5))(2)(C≡CFc)(2)] (Q = NBu(4)) reacts with Tl(+) to give the one-dimensional (1-D) anionic [(NBu(4)){trans,trans,trans-PtTl(C(6)F(5))(2)(C≡CFc)(2)}](n) (2) and neutral [trans,trans,trans-PtTl(2)(C(6)F(5))(2)(C≡CFc)(2)](n) (4) polymeric chains based on [PtFc(2)](2-) platinate fragments and Tl(+) (2) or [Tl···Tl](2+) (4) units, respectively, connected by Pt(II)···Tl(I) and secondary weak κ-η(1) (2) or η(2) (4) alkynyl···Tl(I) bonding. The formation of 1-4 is reversible, and thus treatment of neutral 3 and 4 with PPh(3)MeBr causes the precipitation of TlBr, returning toward the formation of the anionic 1 and 2' (Q = PPh(3)Me). Two slightly different pseudopolymorphs were found for 2', depending on the crystallization solvent. Finally, the reaction of the homoleptic [Pt(C≡CFc)(4)](2-) with 2 equiv of Tl(+) affords the tetradecanuclear sandwich type complex [Pt(2)Tl(4)(C≡CFc)(8)] (6). Electrochemical, spectroelectrochemical, and theoretical studies have been carried out to elucidate the effect produced by the interaction of the Tl(+) with the Pt-C≡CFc fragments. The cyclic voltammetry (CV) and differential pulse voltammetry (DPV) of 1-5 reveal that, in general, neutralization of the anionic fragments increases the stability of the fully oxidized species and

Alteration of mineral crystallinity and collagen cross-linking of bones in osteopetrotic toothless (tl/tl) rats and their improvement after treatment with colony stimulating factor-1

NASA Technical Reports Server (NTRS)

Wojtowicz, A.; Dziedzic-Goclawska, A.; Kaminski, A.; Stachowicz, W.; Wojtowicz, K.; Marks, S. C. Jr; Yamauchi, M.

1997-01-01

A common feature of various types of mammalian osteopetroses is a marked increase in bone mass accompanied by spontaneous bone fractures. The toothless (tl/tl) rat osteopetrotic mutation is characterized by drastically reduced bone resorption due to a profound deficiency of osteoclasts and their precursors. An altered bone morphology has also been observed. The mutants cannot be cured by bone marrow transplantation, but skeletal defects are greatly reduced after treatment with colony stimulating factor 1 (CSF-1). The objectives of this study were to characterize mineral and collagen matrices in cancellous and compact bone isolated from long bones of 6-week-old normal littermates, tl/tl osteopetrotic mutants and mutants (tl/tl) treated with CSF-1. There were no differences in bone mineral content, but a significant decrease in the crystallinity of mineral evaluated by the method based on electron paramagnetic resonance spectrometry was observed in all bones of tl/tl mutants as compared to that of controls. Within the collagen matrix, slight decreases in the labile cross-links, but significant increases in the content of the stable cross-links, pyridinoline, and deoxypyridinoline, were observed in both cancellous and compact bone of osteopetrotic mutants. In tl/tl mutants treated with human recombinant CSF-1, the normalization of the crystallinity of bone mineral as well as collagen cross-links was found. Our results indicate that remodeling of bone matrix in tl/tl mutants is highly suppressed, but that after treatment with CSF-1, this activity recovers significantly. Taken together, these data provide further support for the hypothesis that CSF-1 is an essential factor for normal osteoclast differentiation and bone remodelling.

Myocardial perfusion in patients with suspected coronary artery disease: comparison between 320-MDCT and rubidium-82 PET.

PubMed

Dantas, Roberto Nery; Assuncao, Antonildes Nascimento; Marques, Ismar Aguiar; Fahel, Mateus Guimaraes; Nomura, Cesar Higa; Avila, Luiz Francisco Rodrigues; Giorgi, Maria Clementina Pinto; Soares, Jose; Meneghetti, Jose Claudio; Parga, Jose Rodrigues

2018-06-01

Despite advances in non-invasive myocardial perfusion imaging (MPI) evaluation, computed tomography (CT) multiphase MPI protocols have not yet been compared with the highly accurate rubidium-82 positron emission tomography ( 82 RbPET) MPI. Thus, this study aimed to evaluate agreement between 82 RbPET and 320-detector row CT (320-CT) MPI using a multiphase protocol in suspected CAD patients. Forty-four patients referred for MPI evaluation were prospectively enrolled and underwent dipyridamole stress 82 RbPET and multiphase 320-CT MPI (five consecutive volumetric acquisitions during stress). Statistical analyses were performed using the R software. There was high agreement for recognizing summed stress scores ≥ 4 (kappa 0.77, 95% CI 0.55-0.98, p < 0.001) and moderate for detecting SDS ≥ 2 (kappa 0.51, 95% CI 0.23-0.80, p < 0.001). In a per segment analysis, agreement was high for the presence of perfusion defects during stress and rest (kappa 0.75 and 0.82, respectively) and was moderate for impairment severity (kappa 0.58 and 0.65, respectively). The 320-CT protocol was safe, with low radiation burden (9.3 ± 2.4 mSv). There was a significant agreement between dipyridamole stress 320-CT MPI and 82 RbPET MPI in the evaluation of suspected CAD patients of intermediate risk. The multiphase 320-CT MPI protocol was feasible, diagnostic and with relatively low radiation exposure. • Rubidium-82 PET and 320-MDCT can perform MPI studies for CAD investigation. • There is high agreement between rubidium-82 PET and 320-MDCT for MPI assessment. • Multiphase CT perfusion protocols are feasible and with low radiation. • Multiphase CT perfusion protocols can identify image artefacts.

Hole doping and structural transformation in CsTl1-xHgxCl3.

PubMed

Retuerto, Maria; Yin, Zhiping; Emge, Thomas J; Stephens, Peter W; Li, Man-Rong; Sarkar, Tapati; Croft, Mark C; Ignatov, Alexander; Yuan, Z; Zhang, S J; Jin, Changqing; Paria Sena, Robert; Hadermann, Joke; Kotliar, Gabriel; Greenblatt, Martha

2015-02-02

CsTlCl(3) and CsTlF(3) perovskites have been theoretically predicted to be superconductors when properly hole-doped. Both compounds have been previously prepared as pure compounds: CsTlCl(3) in a tetragonal (I4/m) and a cubic (Fm3̅m) perovskite polymorph and CsTlF(3) as a cubic perovskite (Fm3̅m). In this work, substitution of Tl in CsTlCl(3) with Hg is reported, in an attempt to hole-dope the system and induce superconductivity. The whole series CsTl(1-x)HgxCl(3) (x = 0.0, 0.1, 0.2, 0.4, 0.6, and 0.8) was prepared. CsTl(0.9)Hg(0.1)Cl(3) is tetragonal as the more stable phase of CsTlCl(3). However, CsTl(0.8)Hg(0.2)Cl(3) is already cubic with the space group Fm3̅m and with two different positions for Tl(+) and Tl(3+). For x = 0.4 and 0.5, solid solutions could not be formed. For x ≥ 0.6, the samples are primitive cubic perovskites with one crystallographic position for Tl(+), Tl(3+), and Hg(2+). All of the samples formed are insulating, and there is no signature of superconductivity. X-ray absorption spectroscopy indicates that all of the samples have a mixed-valence state of Tl(+) and Tl(3+). Raman spectroscopy shows the presence of the active Tl-Cl-Tl stretching mode over the whole series and the intensity of the Tl-Cl-Hg mode increases with increasing Hg content. First-principle calculations confirmed that the phases are insulators in their ground state and that Hg is not a good dopant in the search for superconductivity in this system.

Application of TlBr to nuclear medicine imaging

NASA Astrophysics Data System (ADS)

Cirignano, Leonard; Kim, Hadong; Kargar, Alireza; Churilov, Alexei V.; Ciampi, Guido; Higgins, William; Kim, Suyoung; Barber, Bradford; Haston, Kyle; Shah, Kanai

2012-10-01

Thallium bromide (TlBr) has been under development for room temperature gamma ray spectroscopy due to high density, high Z and wide bandgap of the material. Furthermore, its low melting point (460 °C), cubic crystal structure and congruent melting with no solid-solid phase transitions between the melting point and room temperature, TlBr can be grown by relatively simple melt based methods. As a result of improvements in material processing and detector fabrication over the last several years, TlBr with electron mobility-lifetime products (μeτe) in the mid 10-3 cm2/V range has been obtained. In this paper we are going to report on our unipolar charging TlBr results for the application as a small animal imaging. For SPECT application, about 5 mm thick pixellated detectors were fabricated and tested. About 1 % FWHM at 662 keV energy resolution was estimated at room temperature. By applying the depth correction technique, less than 1 % energy resolution was estimated. We are going to report the results from orthogonal strip TlBr detector for PET application. In this paper we also present our latest detector highlights and recent progress made in long term stability of TlBr detectors at or near room temperature. This work is being supported by the Domestic Nuclear Detection Office (DNDO) and the Department of Energy (DOE).

Do thallium myocardial perfusion scan abnormalities predict survival in sarcoid patients without cardiac symptoms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kinney, E.L.; Caldwell, J.W.

1990-07-01

Whereas the total mortality rate for sarcoidosis is 0.2 per 100,000, the prognosis, when the heart is involved, is very much worse. The authors used the difference in mortality rate to infer whether thallium 201 myocardial perfusion scan abnormalities correspond to myocardial sarcoid by making the simplifying assumption that if they do, then patients with abnormal scans will be found to have a death rate similar to patients with sarcoid heart disease. The authors therefore analyzed complete survival data on 52 sarcoid patients without cardiac symptoms an average of eighty-nine months after they had been scanned as part of amore » protocol. By use of survival analysis (the Cox proportional hazards model), the only variable that was significantly associated with survival was age. The patients' scan pattern, treatment status, gender, and race were not significantly related to survival. The authors conclude that thallium myocardial perfusion scans cannot reliably be used to diagnose sarcoid heart disease in sarcoid patients without cardiac symptoms.« less

Design of a digital phantom population for myocardial perfusion SPECT imaging research

NASA Astrophysics Data System (ADS)

Ghaly, Michael; Du, Yong; Fung, George S. K.; Tsui, Benjamin M. W.; Links, Jonathan M.; Frey, Eric

2014-06-01

Digital phantoms and Monte Carlo (MC) simulations have become important tools for optimizing and evaluating instrumentation, acquisition and processing methods for myocardial perfusion SPECT (MPS). In this work, we designed a new adult digital phantom population and generated corresponding Tc-99m and Tl-201 projections for use in MPS research. The population is based on the three-dimensional XCAT phantom with organ parameters sampled from the Emory PET Torso Model Database. Phantoms included three variations each in body size, heart size, and subcutaneous adipose tissue level, for a total of 27 phantoms of each gender. The SimSET MC code and angular response functions were used to model interactions in the body and the collimator-detector system, respectively. We divided each phantom into seven organs, each simulated separately, allowing use of post-simulation summing to efficiently model uptake variations. Also, we adapted and used a criterion based on the relative Poisson effective count level to determine the required number of simulated photons for each simulated organ. This technique provided a quantitative estimate of the true noise in the simulated projection data, including residual MC simulation noise. Projections were generated in 1 keV wide energy windows from 48-184 keV assuming perfect energy resolution to permit study of the effects of window width, energy resolution, and crosstalk in the context of dual isotope MPS. We have developed a comprehensive method for efficiently simulating realistic projections for a realistic population of phantoms in the context of MPS imaging. The new phantom population and realistic database of simulated projections will be useful in performing mathematical and human observer studies to evaluate various acquisition and processing methods such as optimizing the energy window width, investigating the effect of energy resolution on image quality and evaluating compensation methods for degrading factors such as crosstalk in

The electronic structure and thermoelectric properties of BiTl{sub 9}Te{sub 6} and SbTl{sub 9}Te{sub 6}: First-principles calculations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guo, Li Bin; Ye, Lingyun; Wang, Yuan Xu, E-mail: wangyx@henu.edu.cn

2015-12-21

The electronic structure and thermoelectric properties of MTl{sub 9}Te{sub 6} (M = Bi, Sb) were studied using density functional theory and the semiclassical Boltzmann theory. It is found that the band gaps of BiTl{sub 9}Te{sub 6} and SbTl{sub 9}Te{sub 6} are equal to 0.59 eV and 0.72 eV, respectively. The relative large band gap and strong coupling between Sb s and Te p are helpful to the thermoelectric properties of SbTl{sub 9}Te{sub 6}. Near the bottom of the conduction bands, the number of band valleys of SbTl{sub 9}Te{sub 6} is four and is larger than that of BiTl{sub 9}Te{sub 6} (two band valleys),more » which will increase its Seebeck coefficient. Although BiTl{sub 9}Te{sub 6} has a larger electrical conductivity relative to relaxation time (σ/τ) along the z-direction than that of SbTl{sub 9}Te{sub 6}, the results show that the transport properties of SbTl{sub 9}Te{sub 6} are better than those of BiTl{sub 9}Te{sub 6} possibly due to its large Seebeck coefficient. The maximum value of power factor relative to relaxation time (S{sup 2}σ/τ) for SbTl{sub 9}Te{sub 6} reaches 4.30 × 10{sup 11 }W/K{sup 2} m s at 900 K, that is, originated from its relatively large Seebeck coefficient, suggesting its promising thermoelectric performance at high temperature.« less

Optimally Repeatable Kinetic Model Variant for Myocardial Blood Flow Measurements with 82Rb PET.

PubMed

Ocneanu, Adrian F; deKemp, Robert A; Renaud, Jennifer M; Adler, Andy; Beanlands, Rob S B; Klein, Ran

2017-01-01

Purpose. Myocardial blood flow (MBF) quantification with 82 Rb positron emission tomography (PET) is gaining clinical adoption, but improvements in precision are desired. This study aims to identify analysis variants producing the most repeatable MBF measures. Methods. 12 volunteers underwent same-day test-retest rest and dipyridamole stress imaging with dynamic 82 Rb PET, from which MBF was quantified using 1-tissue-compartment kinetic model variants: (1) blood-pool versus uptake region sampled input function (Blood/Uptake-ROI), (2) dual spillover correction (SOC-On/Off), (3) right blood correction (RBC-On/Off), (4) arterial blood transit delay (Delay-On/Off), and (5) distribution volume (DV) constraint (Global/Regional-DV). Repeatability of MBF, stress/rest myocardial flow reserve (MFR), and stress/rest MBF difference (ΔMBF) was assessed using nonparametric reproducibility coefficients (RPC np = 1.45 × interquartile range). Results. MBF using SOC-On, RVBC-Off, Blood-ROI, Global-DV, and Delay-Off was most repeatable for combined rest and stress: RPC np = 0.21 mL/min/g (15.8%). Corresponding MFR and ΔMBF RPC np were 0.42 (20.2%) and 0.24 mL/min/g (23.5%). MBF repeatability improved with SOC-On at stress ( p < 0.001) and tended to improve with RBC-Off at both rest and stress ( p < 0.08). DV and ROI did not significantly influence repeatability. The Delay-On model was overdetermined and did not reliably converge. Conclusion. MBF and MFR test-retest repeatability were the best with dual spillover correction, left atrium blood input function, and global DV.

SoTL Champions: Leveraging Their Lessons Learned

ERIC Educational Resources Information Center

Marcketti, Sara; VanDerZanden, Ann Marie; Leptien, Jennifer R.

2015-01-01

The benefits of conducting SoTL impact individual faculty, staff, students, as well as disciplines, departments, and institutions. In spite of these benefits, colleges and universities, as well as faculty members, do not consistently embrace a broader vision of scholarship, including SoTL. This research explored individual experiences within the…

Constitution diagram on the system TlSe-Tb-Se

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guseinov, G.D.; Kerimova, E.M.; Agamaliev, D.G.

1988-03-01

The constitution diagram of the system TlSe-TbSe was constructed based on the results of differential-thermal, x-ray phase, and microstructural analyses and measurements of the microhardness. The compound TlTbSe/sub 2/, forming by a peritectic reaction, was observed. It was established that the solubility of TbSe in TlSe at room temperature equals 4.0 mole %.

Auger compositional depth profiling of the metal contact-TlBr interface

NASA Astrophysics Data System (ADS)

Nelson, A. J.; Swanberg, E. L.; Voss, L. F.; Graff, R. T.; Conway, A. M.; Nikolic, R. J.; Payne, S. A.; Kim, H.; Cirignano, L.; Shah, K.

2015-08-01

Degradation of room temperature operation of TlBr radiation detectors with time is thought to be due to electromigration of Tl and Br vacancies within the crystal as well as the metal contacts migrating into the TlBr crystal itself due to electrochemical reactions at the metal/TlBr interface. Scanning Auger electron spectroscopy (AES) in combination with sputter depth profiling was used to investigate the metal contact surface/interfacial structure on TlBr devices. Device-grade TlBr was polished and subjected to a 32% HCl etch to remove surface damage and create a TlBr1-xClx surface layer prior to metal contact deposition. Auger compositional depth profiling results reveal non-equilibrium interfacial diffusion after device operation in both air and N2 at ambient temperature. These results improve our understanding of contact/device degradation versus operating environment for further enhancing radiation detector performance.

Routine 18F-2-deoxy-2-fluoro-D-glucose (18F-FDG) myocardial tomography using a normal large field of view gamma-camera.

PubMed

Höflin, F; Ledermann, H; Noelpp, U; Weinreich, R; Rösler, H

1989-12-01

There is a recent need to study glucose metabolism of the heart in ischemic, as well as in "hibernating or stunned" myocardium, and compare it with that in perfusion studies. In non-positron emission tomography centers, positron imaging is possible with a standard Anger-type camera if proper collimation and adequate shielding of the camera crystal can be achieved. For the study with fast-decaying isotopes, seven-pinhole tomography (7PHT), a limited-angle method designed for transaxial tomography of the left ventricle using a nonrotating camera, is well suited, because projections are acquired simultaneously. Individual adjustment (patient supine) of the camera's view axis (CAx) with the left ventricular axis (LVAx) gives excellent results: sensitivity for CHD 82%, specificity 72% in a prospective 201TI study (48 patients, x-ray coronarography as reference). Good alignment of CAx with LVAx is also achieved with the patient prone in LAO in a hammock above the camera surface. In this setting additional lead shielding of the camera is possible using a table reinforced with 5 cm of lead with a central hole for the 7PH-collimator, which has a special lead inlay. This allows utilization of the 511 KeV emitter 18F-FDG, which with a half-life of 109 minutes, can be transported a reasonable distance from the production site. System sensitivity and resolution for 18F was found comparable to 201Tl, 99mTc, and 123I using a phantom. First clinical examinations after 201Tl stress/redistribution studies showed increased 18F-FDG uptake in ischemic heart segments, as well as in "hibernating" nonperfused or "stunned" myocardium.

Studies on 66,67Ga- and 199Tl-poly(N-vinylpyrrolidone) complexes.

PubMed

Lahiri, Susanta; Sarkar, Soumi

2007-03-01

Gallium and thallium radionuclides have both diagnostic and therapeutic applications in the field of nuclear medicine. Poly(N-vinylpyrrolidone) (PVP) is routinely used as a drug base because of its excellent biocompatibility. In this paper, complex formation abilities between no-carrier-added (66,)(67)Ga/(199)Tl radionuclides and PVP have been studied. It has been found that aqueous 5% PVP solution can almost quantitatively back extract (66,)(67)Ga/(199)Tl radionuclides from an organic phase, which proves the complexing ability of PVP with (66,)(67)Ga/(199)Tl. Tl(3+) is more efficient to form Tl-PVP complexes than Tl(+). However, Tl(3+)-PVP complexes are less stable than Ga(3+)-PVP complexes.

Valley spin polarization of Tl/Si(111)

NASA Astrophysics Data System (ADS)

Stolwijk, Sebastian D.; Schmidt, Anke B.; Sakamoto, Kazuyuki; Krüger, Peter; Donath, Markus

2017-11-01

The metal/semiconductor hybrid system Tl/Si(111)-(1 ×1 ) exhibits a unique Tl-derived surface state with remarkable properties. It lies within the silicon band gap and forms spin-momentum-locked valleys close to the Fermi energy at the K ¯ and K¯' points. These valleys are completely spin polarized with opposite spin orientation at K ¯ and K¯' and show a giant spin splitting of more than 0.5 eV. We present a detailed preparation study of the surface system and demonstrate that the electronic valleys are extremely robust, surviving exposure to 100 L hydrogen and 500 L oxygen. We investigate the influence of additional Tl atoms on the spin-polarized valleys. By combining photoemission and inverse photoemission, we prove the existence of fully spin-polarized valleys crossing the Fermi level. Moreover, these metallic valleys carry opposite Berry curvature at K ¯ and K¯', very similar to WSe2, promising a large spin Hall effect. Thus, Tl/Si(111)-(1 ×1 ) possesses all necessary key properties for spintronic applications.

Detailed α -decay study of 180Tl

NASA Astrophysics Data System (ADS)

Andel, B.; Andreyev, A. N.; Antalic, S.; Barzakh, A.; Bree, N.; Cocolios, T. E.; Comas, V. F.; Diriken, J.; Elseviers, J.; Fedorov, D. V.; Fedosseev, V. N.; Franchoo, S.; Ghys, L.; Heredia, J. A.; Huyse, M.; Ivanov, O.; Köster, U.; Liberati, V.; Marsh, B. A.; Nishio, K.; Page, R. D.; Patronis, N.; Seliverstov, M. D.; Tsekhanovich, I.; Van den Bergh, P.; Van De Walle, J.; Van Duppen, P.; Venhart, M.; Vermote, S.; Veselský, M.; Wagemans, C.

2017-11-01

A detailed α -decay spectroscopy study of 180Tl has been performed at ISOLDE (CERN). Z -selective ionization by the Resonance Ionization Laser Ion Source (RILIS) coupled to mass separation provided a high-purity beam of 180Tl. Fine-structure α decays to excited levels in the daughter 176Au were identified and an α -decay scheme of 180Tl was constructed based on an analysis of α -γ and α -γ -γ coincidences. Multipolarities of several γ -ray transitions deexciting levels in 176Au were determined. Based on the analysis of reduced α -decay widths, it was found that all α decays are hindered, which signifies a change of configuration between the parent and all daughter states.

Pharmacologic intervention as an alternative to exercise stress

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gould, K.L.

1987-04-01

Although thallium exercise imaging has served an important role in clinical cardiology, it is significantly limited by suboptimal sensitivity and specificity, particularly in asymptomatic man. The increasing recognition of silent myocardial ischemia, the significant prevalence of coronary artery disease in asymptomatic middle age men, and the frequent occurrence of myocardial infarction without preceding symptoms in 60% of cases emphasizes the need for a more definitive, noninvasive diagnostic test for the presence of coronary artery disease suitable for screening in asymptomatic or symptomatic patients. Intravenous dipyridamole combined with handgrip stress provides a potent stimulus for purposes of diagnostic perfusion imaging. Althoughmore » planar and single photon emission computed tomography (SPECT) imaging also have played an important role, these techniques are seriously hindered by their inability to quantitate radiotracer uptake or image modest differences in maximum relative flow caused by coronary artery stenosis. Accordingly, the combination of dipyridamole-handgrip stress with positron imaging of myocardial perfusion has become a powerful diagnostic tool suitable for routine clinical use. With the availability of generator-produced rubidium-82, dedicated clinically oriented positron cameras, the routine application of positron imaging to clinical cardiology has become feasible. 75 references.« less

Lone pair effect, structural distortions, and potential for superconductivity in Tl perovskites.

PubMed

Schoop, Leslie M; Müchler, Lukas; Felser, Claudia; Cava, R J

2013-05-06

Drawing the analogy to BaBiO3, we investigate via ab initio electronic structure calculations potential new superconductors of the type ATlX3 with A = Rb and Cs and X = F, Cl, and Br, with a particular emphasis on RbTlCl3. On the basis of chemical reasoning, supported by the calculations, we show that Tl-based perovskites have structural and charge instabilities driven by the lone pair effect, similar to the case of BaBiO3, effectively becoming A2Tl(+)Tl(3+)X6. We find that upon hole doping of RbTlCl3, structures without Tl(+) and Tl(3+) charge disproportionation become more stable, although the ideal cubic perovskite, often viewed as the best host for superconductivity, should not be the most stable phase in the system. The known superconductor (Sr,K)BiO3 and hole doped RbTlCl3, predicted to be most stable in the same tetragonal structure, display highly analogous calculated electronic band structures.

Usefulness of automatic QT dispersion measurement for detecting exercise-induced myocardial ischemia.

PubMed

Takase, Bonpei; Masaki, Nobuyuki; Hattori, Hidemi; Ishihara, Masayuki; Kurita, Akira

2009-06-01

The electrocardiographic index of QT dispersion (QTd) is related to the occurrence of arrhythmia. In patients with suspected or known coronary artery disease, QTd may be affected by exercise. We investigated whether QTd that is automatically calculated by a newly developed computer system could be used as a marker of exercise-induced myocardial ischemia. The design of this study was prospective and observational. Eighty-three consecutive patients were enrolled in this study. Their QTd was measured at rest and after 3 min of exercise during exercise-stress Thallium-201 scintigraphy and compared with conventional ST-segment changes. The patients were classified into 4 groups (normal group, redistribution group, fixed defect group, redistribution with fixed defect group) based on the result of single photon emission computed tomography. As statistical analysis, one-way ANOVA with post-hoc Scheffe's method, receiver-operating characteristics (ROC) and multiple logistic regression analysis were performed. At rest, QTd was significantly greater (p<0.05) in the fixed defect group (52+/-21 ms) and the redistribution with fixed defect group (53+/-20 ms) than in the normal group (32+/-14 ms) and the redistribution group (31+/-16 ms). However, QTd tended to increase after exercise in the redistribution group, while QTd tended to decrease in the normal group, the fixed defect group, and the redistribution with fixed defect group (QTd after exercise, normal group, 28+/-17 ms, redistribution group, 35+/-19 ms, fixed defect group, 43+/-25 ms, redistribution with fixed defect group, 49+/-27 ms). Exercise significantly increased QTcd (RR interval-corrected QT dispersion) in the redistribution group. The best cut-off values of QTd and QTcd obtained from ROC curves for exercise-induced myocardial ischemia were 41.6 ms and 40.4 ms, respectively (Qtd--AUC 0.68, 95%CI 0.53- 0.83 and QTcd--AUC 0.67, 95%CI 0.55-0.80). Using these values as cut-off ones, QTd, QTcd, and conventional ST

Visualisation of exercise-induced ischaemia of the right ventricle by thallium-201 single photon emission computed tomography.

PubMed Central

Chiba, J.; Takeishi, Y.; Abe, S.; Tomoike, H.

1997-01-01

OBJECTIVE: Exercise thallium-201 (201T1) single photon emission computed tomography (SPECT) has been used to detect potential ischaemia in the left ventricular myocardium but not in the right ventricle. The purpose of this study was to establish the clinical usefulness of a right ventricular polar map of 201T1 SPECT for visualisation of exercise-induced right ventricular ischaemia. METHODS: Myocardial 201T1 SPECT was obtained immediately after treadmill exercise in 97 patients with suspected coronary artery disease. A region of interest was placed over the right ventricle (RV) on post-stress transaxial images. Short axis images of this region were generated and reconstructed as a bull's eye polar map. Normal ranges of RV 201T1 uptake were determined in 12 patients with normal coronary arteries. Scintigraphic criteria for identifying RV perfusion abnormality were derived from 25 patients with right coronary artery (RCA) stenosis greater than 75%. These criteria were applied to 60 consecutive patients with suspected coronary artery disease. RESULTS: Perfusion defects in the RV were larger in patients with proximal RCA stenosis than in those with distal RCA stenosis (mean (SD) 28 (16)% v 6 (5)%, P < 0.001). The sensitivity and specificity of the RV polar map for the detection of proximal RCA stenosis were 67% (8/12) and 98% (47/48), respectively. RV perfusion defects became undetectable in 9 patients who had successful percutaneous transluminal coronary angioplasty to a proximal RCA lesion. CONCLUSIONS: A right ventricular polar map display was useful for visualising exercise-induced right ventricular ischaemia. Images PMID:9038692

Prediction of Phase Separation of Immiscible Ga-Tl Alloys

NASA Astrophysics Data System (ADS)

Kim, Yunkyum; Kim, Han Gyeol; Kang, Youn-Bae; Kaptay, George; Lee, Joonho

2017-06-01

Phase separation temperature of Ga-Tl liquid alloys was investigated using the constrained drop method. With this method, density and surface tension were investigated together. Despite strong repulsive interactions, molar volume showed ideal mixing behavior, whereas surface tension of the alloy was close to that of pure Tl due to preferential adsorption of Tl. Phase separation temperatures and surface tension values obtained with this method were close to the theoretically calculated values using three different thermodynamic models.

Cardiac phase-synchronized myocardial thallium-201 single-photon emission tomography using list mode data acquisition and iterative tomographic reconstruction.

PubMed

Vemmer, T; Steinbüchel, C; Bertram, J; Eschner, W; Kögler, A; Luig, H

1997-03-01

The purpose of this study was to determine whether data acquisition in the list mode and iterative tomographic reconstruction would render feasible cardiac phase-synchronized thallium-201 single-photon emission tomography (SPET) of the myocardium under routine conditions without modifications in tracer dose, acquisition time, or number of steps of the a gamma camera. Seventy non-selected patients underwent 201T1 SPET imaging according to a routine protocol (74 MBq/2 mCi 201T1, 180 degrees rotation of the gamma camera, 32 steps, 30 min). Gamma camera data, ECG, and a time signal were recorded in list mode. The cardiac cycle was divided into eight phases, the end-diastolic phase encompassing the QRS complex, and the end-systolic phase the T wave. Both phase- and non-phase-synchronized tomograms based on the same list mode data were reconstructed iteratively. Phase-synchronized and non-synchronized images were compared. Patients were divided into two groups depending on whether or not coronary artery disease had been definitely diagnosed prior to SPET imaging. The numbers of patients in both groups demonstrating defects visible on the phase-synchronized but not on the non-synchronized images were compared. It was found that both postexercise and redistribution phase tomograms were suited for interpretation. The changes from end-diastolic to end-systolic images allowed a comparative assessment of regional wall motility and tracer uptake. End-diastolic tomograms provided the best definition of defects. Additional defects not apparent on non-synchronized images were visible in 40 patients, six of whom did not show any defect on the non-synchronized images. Of 42 patients in whom coronary artery disease had been definitely diagnosed, 19 had additional defects not visible on the non-synchronized images, in comparison to 21 of 28 in whom coronary artery disease was suspected (P < 0.02; chi 2). It is concluded that cardiac phase-synchronized 201T1 SPET of the myocardium was

(Tl, Au)/Si(1 1 1){\\sqrt7 \\times \\sqrt7} 2D compound: an ordered array of identical Au clusters embedded in Tl matrix

NASA Astrophysics Data System (ADS)

Mihalyuk, A. N.; Hsing, C. R.; Wei, C. M.; Eremeev, S. V.; Bondarenko, L. V.; Tupchaya, A. Y.; Gruznev, D. V.; Zotov, A. V.; Saranin, A. A.

2018-01-01

Formation of the highly-ordered \\sqrt7 × \\sqrt7 -periodicity 2D compound has been detected in the (Tl, Au)/Si(1 1 1) system as a result of Au deposition onto the Tl/Si(1 1 1) surface, its composition, structure and electronic properties have been characterized using scanning tunneling microscopy, angle-resolved photoelectron spectroscopy and density-functional-theory calculations. On the basis of these data, the structural model of the Tl-Au compound has been proposed, which adopts 12 Tl atoms and 10 Au atoms (in total, 22 atoms) per \\sqrt7 × \\sqrt7 unit cell, i.e.  ˜1.71 ML of Tl and  ˜1.43 ML of Au (in total, ˜3.14 ML). Qualitatively, the model can be visualized as consisting of truncated-pyramid-like Au clusters with a Tl atom on top, while the other Tl atoms form a double layer around the Au clusters. The (Tl, Au)/Si(1 1 1)\\sqrt7 × \\sqrt7 compound has been found to exhibit pronounced metallic properties at least down to temperatures as low as  ˜25 K, which makes it a promising object for studying electrical transport phenomena in the 2D metallic systems.

A study on quantitative analysis of exposure dose caused by patient depending on time and distance in nuclear medicine examination

NASA Astrophysics Data System (ADS)

Kim, H. S.; Cho, J. H.; Shin, S. G.; Dong, K. R.; Chung, W. K.; Chung, J. E.

2013-01-01

This study evaluated possible actions that can help protect against and reduce radiation exposure by measuring the exposure dose for each type of isotope that is used frequently in nuclear medicine before performing numerical analysis of the effective half-life based on the measurement results. From July to August in 2010, the study targeted 10, 6 and 5 people who underwent an 18F-FDG (fludeoxyglucose) positron emission tomography (PET) scan, 99mTc-HDP bone scan, and 201Tl myocardial single-photon emission computed tomography (SPECT) scan, respectively, in the nuclear medicine department. After injecting the required medicine into the subjects, a survey meter was used to measure the dose depending on the distance from the heart and time elapsed. For the 18F-FDG PET scan, the dose decreased by approximately 66% at 90 min compared to that immediately after the injection and by 78% at a distance of 1 m compared to that at 0.3 m. In the 99mTc-HDP bone scan, the dose decreased by approximately 71% in 200 min compared to that immediately after the injection and by approximately 78% at a distance of 1 m compared to that at 0.3 m. In the 201Tl myocardial SPECT scan, the dose decreased by approximately 30% in 250 min compared to that immediately after the injection and by approximately 55% at a distance of 1 m compared to that at 0.3 m. In conclusion, the dose decreases by a large margin depending on the distance and time. In conclusion, this study measured the exposure doses by isotopes, distance from the heart and exposure time, and found that the doses were reduced significantly according the distance and the time.

Electronic Structure of TlBa2CaCu2O(7-Delta)

NASA Technical Reports Server (NTRS)

Vasquez, R. P.; Novikov, D. L.; Freeman, A. J.; Siegal, M. P.

1997-01-01

The core levels of TlBa2CaCu2O(7-delta) (Tl-1212) epitaxial films have been measured with X-ray photoelectron spectroscopy (XPS). The valence electronic structure has been determined using the full-potential linear muffin-tin-orbital band-structure method and measured with XPS. The calculations show that a van Hove singularity (VHS) lies above the Fermi level (E(sub F)) for the stoichiometric compound (delta = 0.5), while for 50% oxygen vacancies in the Tl-O layer (delta = 0.5) E(sub F) is in close proximity to the VHS. Samples annealed in nitrogen (to reduce the hole overdoping by the removal of oxygen) exhibit higher core-level binding energies and a higher T(sub c), consistent with a shift of E(sub F) closer to the VHS. Comparisons are made to the core levels and valence bands of Tl2Ba2CaCu2O(8 + delta)(Tl-2212) and HgBa2CaCu2O)6 + delta) (Hg- 1212). The similarity of the Cu 2p(sub 3/2) spectra for Tl-1212 and Tl-2212 indicates that the number of Tl-O layers has little effect on the Cu-O bonding. However, the Tl-1212 and Hg-1212 Cu 2p(sub 3/2) signals exhibit differences which suggest that the replacement of T(sup 3+) with Hg(sup 2+) results in a decrease in the O 2p right arrow Cu 3d charge-transfer energy and differences in the probabilities of planar vs apical oxygen charge transfer and/or Zhang-Rice singlet-state formation. Differences between the Tl-1212 and the Tl-2212 and Hg-1212 measured valence bands are consistent with the calculated Cu 3d and (Tl,Hg) 6s/5d partial densities of states.

Evidence for topologically protected surface states and a superconducting phase in [Tl4](Tl(1-x)Sn(x))Te3 using photoemission, specific heat, and magnetization measurements, and density functional theory.

PubMed

Arpino, K E; Wallace, D C; Nie, Y F; Birol, T; King, P D C; Chatterjee, S; Uchida, M; Koohpayeh, S M; Wen, J-J; Page, K; Fennie, C J; Shen, K M; McQueen, T M

2014-01-10

We report the discovery of surface states in the perovskite superconductor [Tl4]TlTe3 (Tl5Te3) and its nonsuperconducting tin-doped derivative [Tl4](Tl0.4Sn0.6)Te3 as observed by angle-resolved photoemission spectroscopy. Density functional theory calculations predict that the surface states are protected by a Z2 topology of the bulk band structure. Specific heat and magnetization measurements show that Tl5Te3 has a superconducting volume fraction in excess of 95%. Thus Tl5Te3 is an ideal material in which to study the interplay of bulk band topology and superconductivity.

Magnetism and superconductivity of some Tl-Cu oxides

NASA Technical Reports Server (NTRS)

Datta, Timir

1991-01-01

Many copper oxide based Thallium compounds are now known. In comparison to the Bi-compounds, the Tl-system shows a richer diversity; i.e., High Temperature Superconductors (HTSC) can be obtained with either one or two Tl-0 layers (m = 1,2); also, the triple-digit phases are easier to synthesize. The value of d, oxygen stoichiometry, is critical to achieving superconductivity. The Tl system is robust to oxygen loss; Tl may be lost or incorporated by diffusion. A diffusion coefficient equal to 10 ms at 900 C was determined. Both ortho-rhombic and tetragonal structures are found, but HTSC behavior is indifferent to the crystal symmetry. This system has the highest T(sub c) confirmed. T(sub c) generally increases with p, the number of CuO layers, but tends to saturate at p = 3. Zero resistance was observed at temperatures as great as 125 K. Most of these HTSC's are hole type, but the Ce-doped specimens may be electronic. The magnetic aspects were studied; because in addition to defining the perfectly diamagnetic ground state as in conventional superconductors, magnetism of the copper oxides show a surprising variety. This is true of both the normal and the superconducting states. Also, due to the large phonon contribution to the specific heat at the high T(sub c) jump, electronic density of states, D(Ef), and coherence length are uncertain, and thus, are estimated from the magnetic results. Results from the Tl-system CuO, LaBaCuO,120 and the Bi-CuO compounds are discussed. The emphasis is on the role of magnetism in the Tl-CuO HTSC, but technological aspects are also pointed out.

[A Phase 1 study of beta-methyl-p-(123I)-iodophenyl-pentadecanoic acid (123I-BMIPP)].

PubMed

Torizuka, K; Yonekura, Y; Nishimura, T; Tamaki, N; Uehara, T; Ikekubo, K; Hino, M

1991-07-01

Phase 1 study of beta-methyl-p-(123I)-iodophenylpentadecanoic acid (123I-BMIPP), a new radiopharmaceutical developed for the evaluation of myocardial fatty acid metabolism, was performed in six normal volunteers to evaluate its biodistribution and safety. After intravenous injection of 111 MBq of 123I-BMIPP, the agent accumulated to the myocardium rapidly (5.4 +/- 0.6% at 1.5 hr after injection) and was washed-out slowly (5.1 +/- 0.4% at 3.0hr). 123I-BMIPP demonstrated no significant accumulation to any specific organs other than myocardium, liver and muscle. Myocardium was clearly visualized in the planar and SPECT images obtained 30 min and 3 hrs after injection. The absorption doses from 123I-BMIPP estimated by MIRD method were lower than those from 201Tl in all organs. Neither adverse reactions nor abnormal clinical laboratory findings were found in the safety evaluation. These results suggest 123I-BMIPP is a promising agent for evaluating myocardial fatty acid metabolism.

Electronic effects of Se and Pb dopants in TlBr

NASA Astrophysics Data System (ADS)

Smith, Holland M.; Phillips, David J.; Sharp, Ian D.; Beeman, Jeffrey W.; Chrzan, Daryl C.; Haegel, Nancy M.; Haller, Eugene E.; Ciampi, Guido; Kim, Hadong; Shah, Kanai S.

2012-05-01

Deep levels in Se- and Pb-doped bulk TlBr detectors were characterized with photo-induced conductivity transient spectroscopy (PICTS) and cathodoluminescence (CL). Se-doped TlBr revealed two traps with energies of 0.35 and 0.45 eV in PICTS spectra. The Pb-doped material revealed three levels with energies of 0.11, 0.45, and 0.75 eV. CL measurements in both materials correlate with optical transitions involving some of the identified levels. The ambipolar carrier lifetimes of Se-doped and Pb-doped TlBr were measured with microwave reflectivity transients and found to be significantly lower than the lifetime of undoped TlBr.

Myocardial Bridge

MedlinePlus

... Center > Myocardial Bridge Menu Topics Topics FAQs Myocardial Bridge En español Your heart is made of muscle, ... surface of the heart. What is a myocardial bridge? A myocardial bridge is a band of heart ...

Studies on the lithium transport across the red cell membrane. II. Characterization of ouabain-sensitive and ouabain-insensitive Li+ transport. Effects of bicarbonate and dipyridamole.

PubMed

Duhm, J; Becker, B F

1977-01-17

In studies on Li+ net-transport across the human red cell membrane following results were obtained: 1. In K+- and Na+-free choline chloride media, Li+ is transported into the erythrocytes against an electrochemical gradient. This Li+ uphill transport as well as Li+ downhill transport into the cells is inhibited by ouabain, ATP-depletion, and by external K+ and Na+. The effects of K+ and Na+ are relieved at high Li+ concentrations. 2. Ouabain-sensitive Li+ uptake, determined at 10 mM external Na+, does not obey simple Michaelis-Menten kinetics and exhibits a maximum at about pH 7. 3. Ouabain-resistant Li+ downhill transport into erythrocytes increases with rising pH. It is comprised of a saturating component and a component linearly dependent on external Li+. The linear component is partly inhibited by dipyridamole and accelerated by bicarbonate. The bicarbonate effect can be completely blocked by dipyridamole, phlorizin and phenylbutazone. 4. Li+ release is not inhibited by ouabain, ATP-depletion and external K+. It increases with external Na+ concentration, tending to saturate at 150 mM Na+. Na+-independent Li+ release is stimulated by bicarbonate. It is concluded that ouabain-sensitive Li+ uptake is mediated at the K+-site(s) of the Na+-K+ pump. Li+, K+ and Na+ appear to compete for a common site (or sites). The stimulation of Li+ transfer by bicarbonate and the inhibition by dipyridamole suggest a participation of anionic species in ouabain-resistant Li+ transfer. The Na+-dependent Li+ release and the "saturating component" of Li+ uptake are ascribed to the Na+-dependent Li+ countertransport system.

21 CFR 201.71 - Magnesium labeling.

Code of Federal Regulations, 2014 CFR

2014-04-01

... disease [bullet] a magnesium-restricted diet”. The warnings in §§ 201.64(c), 201.70(c), 201.71(c), and 201...., a magnesium or potassium-restricted diet. 1 See § 201.66(b)(4) of this chapter for definition of...

21 CFR 201.71 - Magnesium labeling.

Code of Federal Regulations, 2012 CFR

2012-04-01

... disease [bullet] a magnesium-restricted diet”. The warnings in §§ 201.64(c), 201.70(c), 201.71(c), and 201...., a magnesium or potassium-restricted diet. 1 See § 201.66(b)(4) of this chapter for definition of...

21 CFR 201.71 - Magnesium labeling.

Code of Federal Regulations, 2013 CFR

2013-04-01

... disease [bullet] a magnesium-restricted diet”. The warnings in §§ 201.64(c), 201.70(c), 201.71(c), and 201...., a magnesium or potassium-restricted diet. 1 See § 201.66(b)(4) of this chapter for definition of...

21 CFR 201.70 - Calcium labeling.

Code of Federal Regulations, 2013 CFR

2013-04-01

... stones [bullet] a calcium-restricted diet”. The warnings in §§ 201.64(c), 201.70(c), 201.71(c), and 201...., a calcium or sodium restricted diet. 1 See § 201.66(b)(4) of this chapter for definition of bullet...

21 CFR 201.70 - Calcium labeling.

Code of Federal Regulations, 2014 CFR

2014-04-01

... stones [bullet] a calcium-restricted diet”. The warnings in §§ 201.64(c), 201.70(c), 201.71(c), and 201...., a calcium or sodium restricted diet. 1 See § 201.66(b)(4) of this chapter for definition of bullet...

21 CFR 201.70 - Calcium labeling.

Code of Federal Regulations, 2012 CFR

2012-04-01

... stones [bullet] a calcium-restricted diet”. The warnings in §§ 201.64(c), 201.70(c), 201.71(c), and 201...., a calcium or sodium restricted diet. 1 See § 201.66(b)(4) of this chapter for definition of bullet...

Characterization of Thallium Bromide (TlBr) for Room Temperature Radiation Detectors

NASA Astrophysics Data System (ADS)

Smith, Holland McTyeire

Thallium bromide (TlBr) has emerged as a remarkably well-suited material for room temperature radiation detection. The unique combination of high-Z elements, high density, suitable band gap, and excellent electrical transport properties present in TlBr have brought device performance up to par with CdZnTe (CZT), the current market-leading room temperature radiation detector material. TlBr research is at an earlier stage than that of CZT, giving hope that the material will see even further improvement in electronic properties. Improving a resistive semiconductor material requires knowledge of deep levels present in the material and the effects of these deep levels on transport properties. Very few deep level studies have been conducted on TlBr, and none with the depth required to generate useful growth suggestions. In this dissertation, deep levels in nominally undoped and doped TlBr samples are studied with electrical and optical methods. Photo-Induced Conductivity Transient Spectroscopy (PICTS) is used to discover many deep levels in TlBr electrically. These levels are compared to sub-band gap optical transitions originating from defects observed in emission spectra. The results of this research indicate that the origin of resistivity in TlBr is likely due to deep level defects pinning the Fermi level at least ˜0.7 eV from either the conduction or valence band edge. The effect of dopants and deep levels on transport in TlBr is assessed with microwave photoconductivity decay analysis. It is found that Pb-, Se-, and O-doping decreases carrier lifetime in TlBr, whereas C-doping does not. TlBr exhibits weak ionic conductivity at room temperature, which both negatively affects the leakage current of detectors and leads to device degradation over time. Researchers are actively looking for ways to reduce or eliminate the ionic conductivity, but are faced with an intriguing challenge of materials engineering: is it possible to mitigate the ionic conduction of Tl

Magnetism and superconductivity of some Tl-Cu oxides

NASA Technical Reports Server (NTRS)

Datta, Timir

1990-01-01

Many copper oxide based Thallium compounds have now been discovered. In comparison to the Bi-compounds, the Tl-system shows a richer diversity; viz., High Temperature Superconductors (HTSC) can be obtained with either one or two Tl-0 layers (m = 1,2); also, the triple-digit phases are easier to synthesize. The value of d, oxygen stoichiometry, is critical to achieving superconductivity. The Tl system is robust to oxygen loss; Tl may be lost or incorporated by diffusion. A diffusion coefficient equal to 10 ms at 900 C was determined. Both ortho-rhombic and tetragonal structures are evidenced, but HTSC behavior is indifferent to the crystal symmetry. This system has the highest T(sub c) confirmed. T(sub c) generally increases with p, the number of CuO layers, but tends to saturate at p = 3. Zero resistance as high as 125K has been observed. Most of these HTSC's are hole type, but the Ce-doped specimens may be electronic. The magnetic aspects were studied; because in addition to defining the perfectly diamagnetic ground state as in the conventional superconductors, magnetism of the copper oxides show a surprising variety. This is true of both the normal and the superconducting states. Also, due to the large phonon contribution to the specific heat at the high T(sub c) accurate thermal measurement of important parameters such as the sp. heat jump, electronic density of states, D(Ef) and coherence length are uncertain, and thus, are estimated from the magnetic results. Results from the Tl-system CuO, LaBaCuO, 120 and the Bi-CuO compounds are discussed. The emphasis is on the role of magnetism in the TlCuO HTSC, but technological aspects are also pointed out.

Indirect radioimmunoassay for thymus leukemia (TL) antigens. [Mice, /sup 125/I tracer technique

DOE Office of Scientific and Technical Information (OSTI.GOV)

Esmon, N.L.; Little, J.R.

1976-09-01

An indirect radioimmunoassay for thymus leukemia TL antigens has been developed and its specificity documented. The assay makes use of anti-TL antibodies produced in congenic mice (A-Tla/sup b/) and radioiodinated purified rabbit anti-mouse IgG. Using this assay, differences can be detected in the amounts of antigen expressed on thymocytes of the three known phenotypes (TL.1,2,3; TL.2; TL/sup -/) of inbred mouse strains. Significant differences are also detected in comparison of the thymocytes from homozygous TL.1,2,3 mice (A-Tla/sup a/) and heterozygotes from Tla/sup a/ and Tla/sup b/ parents. Optimum conditions for the assay have been established. Its ability to detect antigensmore » on glutaraldehyde-fixed cells and the binding of noncytolytic antibodies on both viable and fixed cells are documented. The assay has also been used to quantitate the changes in TL antigen expression on cells incubated in anti-TL antisera under conditions of antigenic modulation.« less

Polarization effect in the Ionic conductor TlBr

NASA Astrophysics Data System (ADS)

Rocha Leao, Cedric; Lordi, Vincenzo

2012-02-01

TlBr is an ionic crystal that in recent years has been standing out as one of the most promising materials for effective room temperature radiation detection. However, its exceptional performance invariably degrades after operation times that vary from hours to several weeks. This phenomenon, known as polarization, is assigned to the undesirable ionic current that sets in the crystal under an applied bias, leading to the accumulation of oppositely charged Tl+ and Br- ions at the electric contacts of the device. This charge build up induces a field that opposes the applied bias, impairing the collection of the photo-induced carriers. In this presentation, we use parameter free quantum mechanical simulations to discuss the possible origins of the polarization effect in TlBr, showing that ionic mobility in the intrinsic material is not enough to account for effects reported by several groups. We then discuss other possible causes for the degradation of biased TlBr and propose ways to prevent its occurrence, via careful co-doping as well as a judicious choice of the metal contacts to be employed.

Annual dose measurements and TL-dating of ancient Egyptian pottery

NASA Astrophysics Data System (ADS)

Abdel-Wahab, M. S.; El-Fiki, S. A.; El-Fiki, M. A.; Gomaa, M.; Abdel-Kariem, S.; El-Faramawy, N.

1996-05-01

In the course of the dating of ancient Egyptian pottery, pottery sherds were collected from three archaeological tombs in Nazlet El Samman region, Giza zone (Egypt). The annual dose from natural background was measured by gamma spectroscopic technique as well as thermoluminescence (TL) measurements. The results of both methods are in good agreement with a consistency of 99.69%. The extracted quartz exhibited TL dating peaks at about(305 ± 5|4)°C. The TL dating shows an age of 4301 ± 100 years for the examined pottery which belongs to the "Fourth Dynasty" in the "Old Kingdom". The uncertainties in TL dating using the additive method are much lower than that of archeologists.

Myocardial Rupture in Acute Myocardial Infarction: Mechanistic Explanation Based on the Ventricular Myocardial Band Hypothesis.

PubMed

Vargas-Barron, Jesús; Antunez-Montes, Omar-Yassef; Roldán, Francisco-Javier; Aranda-Frausto, Alberto; González-Pacheco, Hector; Romero-Cardenas, Ángel; Zabalgoitia, Miguel

2015-01-01

Torrent-Guasp explains the structure of the ventricular myocardium by means of a helical muscular band. Our primary purpose was to demonstrate the utility of echocardiography in human and porcine hearts in identifying the segments of the myocardial band. The second purpose was to evaluate the relation of the topographic distribution of the myocardial band with some post-myocardial infarction ruptures. Five porcine and one human heart without cardiopathy were dissected and the ventricular myocardial segments were color-coded for illustration and reconstruction purposes. These segments were then correlated to the conventional echocardiographic images. Afterwards in three cases with post-myocardial infarction rupture, a correlation of the topographic location of the rupture with the distribution of the ventricular band was made. The human ventricular band does not show any differences from the porcine band, which confirms the similarities of the four segments; these segments could be identified by echocardiography. In three cases with myocardial rupture, a correlation of the intra-myocardial dissection with the distribution of the ventricular band was observed. Echocardiography is helpful in identifying the myocardial band segments as well as the correlation with the topographic distribution of some myocardial post-infarction ruptures.

L-moments and TL-moments of the generalized lambda distribution

USGS Publications Warehouse

Asquith, W.H.

2007-01-01

The 4-parameter generalized lambda distribution (GLD) is a flexible distribution capable of mimicking the shapes of many distributions and data samples including those with heavy tails. The method of L-moments and the recently developed method of trimmed L-moments (TL-moments) are attractive techniques for parameter estimation for heavy-tailed distributions for which the L- and TL-moments have been defined. Analytical solutions for the first five L- and TL-moments in terms of GLD parameters are derived. Unfortunately, numerical methods are needed to compute the parameters from the L- or TL-moments. Algorithms are suggested for parameter estimation. Application of the GLD using both L- and TL-moment parameter estimates from example data is demonstrated, and comparison of the L-moment fit of the 4-parameter kappa distribution is made. A small simulation study of the 98th percentile (far-right tail) is conducted for a heavy-tail GLD with high-outlier contamination. The simulations show, with respect to estimation of the 98th-percent quantile, that TL-moments are less biased (more robost) in the presence of high-outlier contamination. However, the robustness comes at the expense of considerably more sampling variability. ?? 2006 Elsevier B.V. All rights reserved.

Leading the Charge for SoTL--Embracing Collaboration

ERIC Educational Resources Information Center

Cassard, Anita; Sloboda, Brian

2014-01-01

The scholarship of teaching and learning (SoTL) enables colleges and universities to assess student learning and measure the outcomes by engaging in meaningful research, and to disseminate this research. The objective of this paper is to give a snapshot of and assess the current thinking behind this scholarship by presenting examples of SoTL, and…

Prognostic significance of normal quantitative planar thallium-201 stress scintigraphy in patients with chest pain

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wackers, F.J.; Russo, D.J.; Russo, D.

The prognostic significance of normal quantitative planar thallium-201 stress scintigraphy was evaluated in patients with a chest pain syndrome. The prevalence of cardiac events during follow-up was related to the pretest (that is, before stress scintigraphy) likelihood of coronary artery disease determined on the basis of symptoms, age, sex and stress electrocardiography. In a consecutive series of 344 patients who had adequate thallium-201 stress scintigrams, 95 had unequivocally normal studies by quantitative analysis. The pretest likelihood of coronary artery disease in the 95 patients had a bimodal distribution. During a mean follow-up period of 22 +/- 3 months, no patientmore » died. Three patients (3%) had a cardiac event: two of these patients (pretest likelihood of coronary artery disease 54 and 94%) had a nonfatal myocardial infarction 8 and 22 months, respectively, after stress scintigraphy, and one patient (pretest likelihood 98%) underwent percutaneous transluminal coronary angioplasty 16 months after stress scintigraphy for persisting anginal complaints. Three patients were lost to follow-up; all three had a low pretest likelihood of coronary artery disease. It is concluded that patients with chest pain and normal findings on quantitative thallium-201 scintigraphy have an excellent prognosis. Cardiac events are rare (infarction rate 1% per year) and occur in patients with a moderate to high pretest likelihood of coronary artery disease.« less

Personal Reflection: SoTL and Don't Perish!

ERIC Educational Resources Information Center

Goh, Gerald Guan Gan

2010-01-01

This reflection describes my early encounters with SoTL as I went through a critical period questioning my role and responsibilities as an academic and my journey with a cohort of students who made me realise that there is indeed a dire need for SoTL to bridge the nexus between a university academic's teaching responsibilities as well as the…

Impurity-induced deep centers in Tl 6SI 4

DOE PAGES

Shi, Hongliang; Lin, Wenwen; Kanatzidis, Mercouri G.; ...

2017-04-13

Tl 6SI 4 is a promising material for room-temperature semiconductor radiation detection applications. The history of the development of semiconductor radiation detection materials has demonstrated that impurities strongly affect the carrier transport and that material purification is a critically important step in improving the carrier transport and thereby the detector performance. Here, we report combined experimental and theoretical studies of impurities in Tl 6SI 4. Impurity concentrations in Tl 6SI 4 were analyzed by glow discharge mass spectrometry. Purification of the raw material by multi-pass vertical narrow zone refining was found to be effective in reducing the concentrations of mostmore » impurities. Density functional theory calculations were also performed to study the trapping levels introduced by the main impurities detected in experiments. We show that, among dozens of detected impurities, most are either electrically inactive or shallow. In the purified Tl 6SI 4 sample, only Bi has a significant concentration (0.2 ppm wt) and introduces deep electron trapping levels in the band gap. Lastly, improvement of the purification processes is expected to further reduce the impurity concentrations and their impact on carrier transport in Tl 6SI 4, leading to improved detector performance.« less

10 CFR 835.201 - [Reserved

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 4 2010-01-01 2010-01-01 false [Reserved] 835.201 Section 835.201 Energy DEPARTMENT OF ENERGY OCCUPATIONAL RADIATION PROTECTION Standards for Internal and External Exposure § 835.201 [Reserved] ...

10 CFR 835.201 - [Reserved

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 4 2012-01-01 2012-01-01 false [Reserved] 835.201 Section 835.201 Energy DEPARTMENT OF ENERGY OCCUPATIONAL RADIATION PROTECTION Standards for Internal and External Exposure § 835.201 [Reserved] ...

10 CFR 835.201 - [Reserved

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 4 2013-01-01 2013-01-01 false [Reserved] 835.201 Section 835.201 Energy DEPARTMENT OF ENERGY OCCUPATIONAL RADIATION PROTECTION Standards for Internal and External Exposure § 835.201 [Reserved] ...

10 CFR 835.201 - [Reserved

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 4 2014-01-01 2014-01-01 false [Reserved] 835.201 Section 835.201 Energy DEPARTMENT OF ENERGY OCCUPATIONAL RADIATION PROTECTION Standards for Internal and External Exposure § 835.201 [Reserved] ...

10 CFR 835.201 - [Reserved

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 4 2011-01-01 2011-01-01 false [Reserved] 835.201 Section 835.201 Energy DEPARTMENT OF ENERGY OCCUPATIONAL RADIATION PROTECTION Standards for Internal and External Exposure § 835.201 [Reserved] ...

Dielectric and Raman spectroscopy of TlSe thin films

NASA Astrophysics Data System (ADS)

Ozel, Aysen E.; Deger, Deniz; Celik, Sefa; Yakut, Sahin; Karabak, Binnur; Akyüz, Sevim; Ulutas, Kemal

2017-12-01

In this report, the results of Dielectric and Raman spectroscopy of TlSe thin films are presented. The films were deposited in different thicknesses ranging from 290 Å to 3200 Å by thermal evaporation method. The relative permittivity (dielectric constant εr‧) and dielectric loss (εr″) of TlSe thin films were calculated by measuring capacitance (C) and dielectric loss factor (tan δ) in the frequencies ranging between 10-2 Hz-107 Hz and in the temperature ranging between 173 K and 433 K. In the given intervals, both the dielectric constant and the dielectric loss of TlSe thin films decrease with increasing frequency, but increase with increasing temperature. This behavior can be explained as multicomponent polarization in the structure. The ac conductivity obeys the ωs law when s (s < 1). The dielectric constant of TlSe thin films is determined from Dielectric and Raman spectroscopy measurements. The results obtained by two different methods are in agreement with each other.

Toll-like receptor 2 mediates mesenchymal stem cell-associated myocardial recovery and VEGF production following acute ischemia-reperfusion injury

PubMed Central

Abarbanell, Aaron M.; Wang, Yue; Herrmann, Jeremy L.; Weil, Brent R.; Poynter, Jeffrey A.; Manukyan, Mariuxi C.

2010-01-01

Toll-like receptor 2 (TLR2), a key component of the innate immune system, is linked to inflammation and myocardial dysfunction after ischemia-reperfusion injury (I/R). Treatment of the heart with mesenchymal stem cells (MSCs) is known to improve myocardial recovery after I/R in part by paracrine factors such as VEGF. However, it is unknown whether TLR2 activation on the MSCs affects MSC-mediated myocardial recovery and VEGF production. We hypothesized that the knockout of TLR2 on the MSCs (TLR2KO MSCs) would 1) improve MSC-mediated myocardial recovery and 2) increase myocardial and MSC VEGF release. With the isolated heart perfusion system, Sprague-Dawley rat hearts were subjected to I/R and received one of three intracoronary treatments: vehicle, male wild-type MSCs (MWT MSCs), or TL2KO MSCs. All treatments were performed immediately before ischemia, and heart function was measured continuously. Postreperfusion, heart homogenates were analyzed for myocardial VEGF production. Contrary to our hypothesis, only MWT MSC treatment significantly improved the recovery of left ventricular developed pressure and the maximal positive and negative values of the first derivative of pressure. In addition, VEGF production was greatest in hearts treated with MWT MSCs. To investigate MSC production of VEGF, MSCs were activated with TNF in vitro and the supernatants collected for ELISA. In vitro basal levels of MSC VEGF production were similar. However, with TNF activation, MWT MSCs produced significantly more VEGF, whereas activated TLR2KO MSC production of VEGF was unchanged. Finally, we observed that MWT MSCs proliferated more rapidly than TLR2KO MSCs. These data indicate that TLR2 may be essential to MSC-mediated myocardial recovery and VEGF production. PMID:20173040

Development of TlBr detectors for PET imaging.

PubMed

Ariño-Estrada, Gerard; Du, Junwei; Kim, Hadong; Cirignano, Leonard J; Shah, Kanai S; Cherry, Simon R; Mitchell, Gregory S

2018-05-04

Thallium bromide (TlBr) is a promising semiconductor detector material for positron emission tomography (PET) because it can offer very good energy resolution and 3-D segmentation capabilities, and it also provides detection efficiency surpassing that of commonly used scintillators. Energy, timing, and spatial resolution were measured for thin (<1 mm) TlBr detectors. The energy and timing resolution were measured simultaneously for the same planar 0.87 mm-thick TlBr device. An energy resolution of (6.41.3)% at 511 keV was achieved at -400 V bias voltage and at room temperature. A timing resolution of (27.84.1) ns FWHM was achieved for the same operating conditions when appropriate energy gating was applied. The intrinsic spatial resolution was measured to be 0.9 mm FWHM for a TlBr detector with metallic strip contacts of 0.5 mm pitch. As material properties improve, higher bias voltage should improve timing performance. A stack of thin detectors with finely segmented readout can create a modular detector with excellent energy and spatial resolution for PET applications. . © 2018 Institute of Physics and Engineering in Medicine.

Revision of gonadal radiation dose to man from thallium-201

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hosain, P.; Hosain, F.

1981-06-01

Thallium-201 as thallous chloride is now routinely used for myocardial imaging. We observed a biological translocation of T1-201 leading to a gradual increase in the concentration of radioactivity in the testes which facilitated testicular imaging. The initial distribution of intravenously injected tracer dose is greatly dependent on the distribution of cardiac output, but its metabolic fate is analogous to the potassium ion. We have extensively studied the kinetics of thallium in rats, and also carried out limited comparative studies in different species. An attempt was also made to compare the uptake values that could be obtained in dogs by quantitativemore » imaging and by autopsy. Separation of scrotum, epididymis and testes revealed that the increase in uptake occurred predominantly in the testes. The uptake increased with time for about 1 day, and after 2 days it declined with a biological half-life of approximately 2 days. The later phase of testicular clearance was similar to the rate of clearance from other organs. The testicular uptake of T1-201 was highest in rats: the initial value at 10 to 15 min was 0.48 +- 0.09% of the injected dose which increased to 1.77 +- 0.20% by 1 day. The initial uptake in mice was low (0.18 +- 0.06%) but it increased to about 4 folds by 1 day. Values in human, extrapolated from limited quantitative imaging, was similar to mice. These studies indicated the need for the revision of the gonadal radiation dose to man. Calculations show, contrary to the accepted value of about 0.5 rads/mCi, an approximate value of 1.5 rads/mCi is more realistic.« less

Pentavalent and tetravalent uranium selenides, Tl3Cu4USe6 and Tl2Ag2USe4: syntheses, characterization, and structural comparison to other layered actinide chalcogenide compounds.

PubMed

Bugaris, Daniel E; Choi, Eun Sang; Copping, Roy; Glans, Per-Anders; Minasian, Stefan G; Tyliszczak, Tolek; Kozimor, Stosh A; Shuh, David K; Ibers, James A

2011-07-18

The compounds Tl(3)Cu(4)USe(6) and Tl(2)Ag(2)USe(4) were synthesized by the reaction of the elements in excess TlCl at 1123 K. Both compounds crystallize in new structure types, in space groups P2(1)/c and C2/m, respectively, of the monoclinic system. Each compound contains layers of USe(6) octahedra and MSe(4) (M = Cu, Ag) tetrahedra, separated by Tl(+) cations. The packing of the octahedra and the tetrahedra within the layers is compared to the packing arrangements found in other layered actinide chalcogenides. Tl(3)Cu(4)USe(6) displays peaks in its magnetic susceptibility at 5 and 70 K. It exhibits modified Curie-Weiss paramagnetic behavior with an effective magnetic moment of 1.58(1) μ(B) in the temperature range 72-300 K, whereas Tl(2)Ag(2)USe(4) exhibits modified Curie-Weiss paramagnetic behavior with μ(eff) = 3.4(1) μ(B) in the temperature range 100-300 K. X-ray absorption near-edge structure (XANES) results from scanning transmission X-ray spectromicroscopy confirm that Tl(3)Cu(4)USe(6) has Se bonding characteristic of discrete Se(2-) units, Cu bonding generally representative of Cu(+), and U bonding consistent with a U(4+) or U(5+) species. On the basis of these measurements, as well as bonding arguments, the formal oxidation states for U may be assigned as +5 in Tl(3)Cu(4)USe(6) and +4 in Tl(2)Ag(2)USe(4).

40 CFR 243.201 - Safety.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 25 2011-07-01 2011-07-01 false Safety. 243.201 Section 243.201 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES GUIDELINES FOR THE STORAGE... Procedures § 243.201 Safety. ...

40 CFR 243.201 - Safety.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Safety. 243.201 Section 243.201 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES GUIDELINES FOR THE STORAGE... Procedures § 243.201 Safety. ...

Biochemical and Structural Characterization of the Human TL1A Ectodomain

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhan, C.; Yan, Q; Patskovsky, Y

TNF-like 1A (TL1A) is a newly described member of the TNF superfamily that is directly implicated in the pathogenesis of autoimmune diseases, including inflammatory bowel disease, atherosclerosis, and rheumatoid arthritis. We report the crystal structure of the human TL1A extracellular domain at a resolution of 2.5 {angstrom}, which reveals a jelly-roll fold typical of the TNF superfamily. This structural information, in combination with complementary mutagenesis and biochemical characterization, provides insights into the binding interface and the specificity of the interactions between TL1A and the DcR3 and DR3 receptors. These studies suggest that the mode of interaction between TL1A and DcR3more » differs from other characterized TNF ligand/receptor complexes. In addition, we have generated functional TL1A mutants with altered disulfide bonding capability that exhibit enhanced solution properties, which will facilitate the production of materials for future cell-based and whole animal studies. In summary, these studies provide insights into the structure and function of TL1A and provide the basis for the rational manipulation of its interactions with cognate receptors.« less

Native defects in Tl 6SI 4: Density functional calculations

DOE PAGES

Shi, Hongliang; Du, Mao -Hua

2015-05-05

In this study, Tl 6SI 4 is a promising room-temperature semiconductor radiation detection material. Here, we report density functional calculations of native defects and dielectric properties of Tl 6SI 4. Formation energies and defect levels of native point defects and defect complexes are calculated. Donor-acceptor defect complexes are shown to be abundant in Tl 6SI 4. High resistivity can be obtained by Fermi level pinning by native donor and acceptor defects. Deep donors that are detrimental to electron transport are identified and methods to mitigate such problem are discussed. Furthermore, we show that mixed ionic-covalent character of Tl 6SI 4more » gives rise to enhanced Born effective charges and large static dielectric constant, which provides effective screening of charged defects and impurities.« less

46 CFR 308.201 - [Reserved

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 8 2010-10-01 2010-10-01 false [Reserved] 308.201 Section 308.201 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION EMERGENCY OPERATIONS WAR RISK INSURANCE War Risk Protection and Indemnity Insurance § 308.201 [Reserved] ...

46 CFR 308.201 - [Reserved

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 8 2011-10-01 2011-10-01 false [Reserved] 308.201 Section 308.201 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION EMERGENCY OPERATIONS WAR RISK INSURANCE War Risk Protection and Indemnity Insurance § 308.201 [Reserved] ...

46 CFR 308.201 - [Reserved

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 8 2012-10-01 2012-10-01 false [Reserved] 308.201 Section 308.201 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION EMERGENCY OPERATIONS WAR RISK INSURANCE War Risk Protection and Indemnity Insurance § 308.201 [Reserved] ...

46 CFR 308.201 - [Reserved

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 8 2014-10-01 2014-10-01 false [Reserved] 308.201 Section 308.201 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION EMERGENCY OPERATIONS WAR RISK INSURANCE War Risk Protection and Indemnity Insurance § 308.201 [Reserved] ...

46 CFR 308.201 - [Reserved

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 8 2013-10-01 2013-10-01 false [Reserved] 308.201 Section 308.201 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION EMERGENCY OPERATIONS WAR RISK INSURANCE War Risk Protection and Indemnity Insurance § 308.201 [Reserved] ...

One-atom-layer 4×4 compound in (Tl, Pb)/Si(111) system

NASA Astrophysics Data System (ADS)

Mihalyuk, A. N.; Hsing, C. R.; Wei, C. M.; Gruznev, D. V.; Bondarenko, L. V.; Tupchaya, A. Y.; Zotov, A. V.; Saranin, A. A.

2017-03-01

An ordered 4×4-periodicity 2D compound has been found in the (Tl, Pb)/Si(111) system and its composition, structure and electronic properties have been characterized using low-energy electron diffraction, scanning tunneling microscopy observations and density-functional-theory calculations. The compound has been concluded to contain 9 Tl atoms and 12 Pb atoms per 4×4 unit cell, i.e., 0.56 ML of Tl and 0.75 ML of Pb. Structural model was proposed for the 4×4-(Tl, Pb) compound where building blocks are a hexagonal array of 12 Pb atoms, a triangular array of 6 Tl atoms and a Tl trimer. The proposed structure has a C3 symmetry and occurs in the two equivalent orientations. The electron band structure of the compound contains two metallic spin-split surface-state bands. Bearing in mind the advanced properties of the known √{ 3 } ×√{ 3 } 2D compound in the same (Tl, Pb)/Si(111) system (i.e., combination of giant Rashba effect and superconductivity), the found 4×4-(Tl, Pb) compound is believed to be a promising object for exploration of its superconductive properties.

Antireflective coating for AgBr-TlI and AgBr-TlBr0.46I0.54 solid solution crystals

NASA Astrophysics Data System (ADS)

Korsakov, Alexandr; Salimgareev, Dmitrii; Lvov, Alexandr; Zhukova, Liya

2016-12-01

We researched the process of ultraviolet (UV) irradiation for the crystals of AgBr-TlI and AgBr-TlBr0.46I0.54 systems. It was found that on the surface of irradiated crystals, the film is formed and film grain size depends on exposure time and crystal composition. This film proved to gain the transmission by reducing the reflection from its surface within the 8.0-27.0 μm range.

Effect of chlorination on the TlBr band edges for improved room temperature radiation detectors: Effect of chlorination on the TlBr band edges for radiation detectors

DOE PAGES

Varley, J. B.; Conway, A. M.; Voss, L. F.; ...

2015-02-09

Thallium bromide (TlBr) crystals subjected to hydrochloric acid (HCl) chemical treatments have been shown to advantageously affect device performance and longevity in TlBr-based room temperature radiation detectors, yet the exact mechanisms of the improvements remain poorly understood. Here in this paper, we investigate the influence of several HCl chemical treatments on device-grade TlBr and describe the changes in the composition and electronic structure of the surface. Composition analysis and depth profiles obtained from secondary ion mass spectrometry (SIMS) identify the extent to which each HCl etch condition affects the detector surface region and forms of a graded TlBr/TlBr 1-xCL xmore » surface heterojunction. Using a combination of X-ray photoemission spectroscopy (XPS) and hybrid density functional calculations, we are able to determine the valence band offsets, band gaps, and conduction band offsets as a function of Cl content over the entire composition range of TIBr 1-xC1 X. This study establishes a strong correlation between device process conditions, surface chemistry, and electronic structure with the goal of further optimizing the long-term stability and radiation response of TlBr-based detectors.« less

Investigating the origins of double photopeaks in CsI:Tl samples through activator mapping

NASA Astrophysics Data System (ADS)

Onken, Drew R.; Gridin, Sergii; Williams, Richard T.; Williams, Charles B.; Donati, George L.; Gayshan, Vadim; Vasyukov, Sergey; Gektin, Alex

2018-06-01

Careful examination of the origins of double photopeaks in CsI:Tl provides a foundation for exploring the relationship between activator homogeneity and photopeak resolution in scintillators. In rare cases, certain CsI:Tl crystals exhibit a second photopeak in the pulse-height spectrum. A combination of optical mapping and ICP-MS measurements reveals the presence of two distinct regions with differing Tl concentrations in these crystals. The oscillator strength of the 299 nm absorption A-band of Tl in CsI was measured to be 0.0526 ± 0.0008; this parameter can be used to quantify activator concentration from the optical absorption. Using published measurements of luminescence intensity versus Tl concentration, the distributions of Tl measured from optical absorption maps of the samples were reconstructed into photopeaks in good agreement with experiment. The distribution of Tl concentrations in these particular crystals allowed examining luminescence pulse shape as a function of Tl concentration.

Effects of Insulin Resistance on Myocardial Blood Flow and Arterial Peripheral Circulation in Patients with Polycystic Ovary Syndrome.

PubMed

Aldrighi, José M; Tsutsui, Jeane M; Kowastch, Ingrid; Ribeiro, Alessandra L; Scapinelli, Alessandro; Tamanaha, Sonia; Oliveira, Ricardo M; Mathias, Wilson

2015-08-01

Polycystic ovary syndrome (PCOS) is associated with increased risk for cardiovascular disease. We sought to evaluate the effects of insulin resistance (IR) on myocardial microcirculation and peripheral artery function in patients with PCOS. We studied 55 women (28 with PCOS without IR, 18 with PCOS and IR and 11 normal controls) who underwent laboratorial analysis, high-resolution vascular ultrasound and real time myocardial contrast echocardiography (RTMCE). Intima-media thickness (IMT) and brachial artery flow-mediated dilation (FMD) were evaluated by vascular ultrasound. The replenishment velocity (β), plateau of acoustic intensity (A) and myocardial blood flow reserve (MBFR) were determined by quantitative dipyridamole stress RTMCE. β reserve in group PCOS + IR was lower than control (2.34 ± 0.55 vs. 3.60 ± 0.6; P < 0.001) and than PCOS without IR (2.34 ± 0.55 vs. 3.17 ± 0.65; P < 0.001). MBFR in patients with PCOS without IR did not differ from those of control (4.59 ± 1.59 vs. 5.30 ± 1.64; P = 0.22) or from patients with PCOS + IR (4.59 ± 1.59 vs. 3.70 ± 1.47; P = 0.07). When comparing with control group, patients with PCOS + IR had lower MBFR (5.30 ± 1.64 vs. 3.70 ± 1.47; P = 0.01). No significant differences were found between control, PCOS without IR and PCOS + IR for FMD (0.18 ± 0.05, 0.15 ± 0.04 and 0.13 ± 0.07; P =NS) or IMT (0.48 ± 0.05, 0.47 ± 0.05 and 0.49 ± 0.07; P = NS). Women with PCOS and IR had depressed β and MBFR as demonstrated by quantitative RTMCE, but no alteration in endothelial dysfunction or IMT. PCOS without IR showed isolated depression in β reserve, probably an earlier marker of myocardial flow abnormality. © 2014, Wiley Periodicals, Inc.

48 CFR 1519.201 - Policy.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 48 Federal Acquisition Regulations System 6 2012-10-01 2012-10-01 false Policy. 1519.201 Section 1519.201 Federal Acquisition Regulations System ENVIRONMENTAL PROTECTION AGENCY SOCIOECONOMIC PROGRAMS SMALL BUSINESS PROGRAMS Policies 1519.201 Policy. Each program's Assistant or Associate Administrator...

48 CFR 1519.201 - Policy.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 48 Federal Acquisition Regulations System 6 2014-10-01 2014-10-01 false Policy. 1519.201 Section 1519.201 Federal Acquisition Regulations System ENVIRONMENTAL PROTECTION AGENCY SOCIOECONOMIC PROGRAMS SMALL BUSINESS PROGRAMS Policies 1519.201 Policy. Each program's Assistant or Associate Administrator...

Assessment of myocardial viability using 123I-labeled iodophenylpentadecanoic acid at sustained low flow or after acute infarction and reperfusion.

PubMed

Yang, J Y; Ruiz, M; Calnon, D A; Watson, D D; Beller, G A; Glover, D K

1999-05-01

123I-labeled iodophenylpentadecanoic acid (IPPA) is a synthetic fatty acid that may be useful for determination of myocardial viability. We investigated the uptake and clearance kinetics of this tracer in canine models of ischemia and infarction. In protocol 1, 185 MBq (5 mCi) 123I-IPPA were injected intravenously in 19 dogs with 50% left anterior descending artery (LAD) flow reduction. In 9 dogs, 201TI was coinjected. In protocol 2, 5 dogs underwent LAD occlusion for 3 h, and 123I-IPPA was injected 60 min after reperfusion. All dogs had flow measured by microspheres, regional systolic thickening by ultrasonic crystals and measurements of postmortem risk area and infarct size. Tracer activities were quantified by gamma well counting and by serial imaging. In protocol 1 dogs with sustained low flow (50% +/- 4%) and absence of systolic thickening (-3.2% +/- 1%), 123I-IPPA defect magnitude (LAD/left circumflex artery [LCX] count ratios) decreased from 0.65 +/- 0.02 to 0.74 +/- 0.02 at 30 min and to 0.84 +/- 0.03 at 2 h (P < 0.01), indicative of rest redistribution. Final transmural 123I-IPPA LAD/LCX activity ratio (0.99 +/- 0.05) was significantly greater than the flow ratio (0.53 +/- 0.04) at injection, confirming complete rest redistribution. The final 123I-IPPA activity ratio was significantly greater than the 201TI ratio over the 2-h period (P < 0.01). In protocol 2 dogs that underwent 3 h of total LAD occlusion and reflow (infarct size = 51% +/- 13% of risk area), viability was overestimated with 123I-IPPA, because uptake averaged 64% of normal in the central necrotic region, where flow averaged < 10% of normal. These findings suggest that serial 123I-IPPA imaging may be useful for assessing myocardial viability under conditions of sustained low flow and myocardial asynergy, such as appears to exist in patients with chronic coronary artery disease and depressed left ventricular function. In contrast, 123I-IPPA given early after reperfusion following prolonged

Secondary interactions in thallium(I) coordination, [Tl 2(DBM) 2] n, DBM - = 1,3-diphenylpropane-1,3-dionate (dibenzoylmethanide)

NASA Astrophysics Data System (ADS)

Askarinejad, Azadeh; Morsali, Ali; Zhu, Long-Guan

2006-05-01

The Tl I complex of 1,3-diphenylpropane-1,3-dionate (dibenzoylmethanide, DBM -), [Tl 2(DBM) 2] n, has been synthesized and characterized. The single-crystal X-ray data show there are two different Tl environments. One type of Tl-atom in the TlO 4C 6Tl 2 environment is twelve-coordinated, with two weak Tl⋯Tl and hexahapto ( η) interactions, TlC 6. The other type of Tl-atom in the TlO 4C 2Tl 2 units is eight-coordinated, with two weak Tl⋯Tl and dihapto ( η) interactions, TlC 2. The dimeric units [Tl 2(DBM) 2] linked through Tl⋯Tl and polyhapto interactions, TlC 6 and TlC 2, and produce the 1D polymeric chains. Comparison with the analogous Pb(II) compound indicates that Tl I may also act as both a Lewis acid and a Lewis base.

Regional analysis of annual maximum rainfall using TL-moments method

NASA Astrophysics Data System (ADS)

Shabri, Ani Bin; Daud, Zalina Mohd; Ariff, Noratiqah Mohd

2011-06-01

Information related to distributions of rainfall amounts are of great importance for designs of water-related structures. One of the concerns of hydrologists and engineers is the probability distribution for modeling of regional data. In this study, a novel approach to regional frequency analysis using L-moments is revisited. Subsequently, an alternative regional frequency analysis using the TL-moments method is employed. The results from both methods were then compared. The analysis was based on daily annual maximum rainfall data from 40 stations in Selangor Malaysia. TL-moments for the generalized extreme value (GEV) and generalized logistic (GLO) distributions were derived and used to develop the regional frequency analysis procedure. TL-moment ratio diagram and Z-test were employed in determining the best-fit distribution. Comparison between the two approaches showed that the L-moments and TL-moments produced equivalent results. GLO and GEV distributions were identified as the most suitable distributions for representing the statistical properties of extreme rainfall in Selangor. Monte Carlo simulation was used for performance evaluation, and it showed that the method of TL-moments was more efficient for lower quantile estimation compared with the L-moments.

23 CFR 620.201 - Purpose.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 23 Highways 1 2014-04-01 2014-04-01 false Purpose. 620.201 Section 620.201 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS ENGINEERING Relinquishment of Highway Facilities § 620.201 Purpose. To prescribe Federal Highway Administration (FHWA...

48 CFR 6.201 - Policy.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Policy. 6.201 Section 6.201 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION ACQUISITION PLANNING COMPETITION REQUIREMENTS Full and Open Competition After Exclusion of Sources 6.201 Policy. Acquisitions made...

48 CFR 6.201 - Policy.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 48 Federal Acquisition Regulations System 1 2013-10-01 2013-10-01 false Policy. 6.201 Section 6.201 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION ACQUISITION PLANNING COMPETITION REQUIREMENTS Full and Open Competition After Exclusion of Sources 6.201 Policy. Acquisitions made...

23 CFR 620.201 - Purpose.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 23 Highways 1 2010-04-01 2010-04-01 false Purpose. 620.201 Section 620.201 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS ENGINEERING Relinquishment of Highway Facilities § 620.201 Purpose. To prescribe Federal Highway Administration (FHWA...

23 CFR 620.201 - Purpose.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 23 Highways 1 2011-04-01 2011-04-01 false Purpose. 620.201 Section 620.201 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS ENGINEERING Relinquishment of Highway Facilities § 620.201 Purpose. To prescribe Federal Highway Administration (FHWA...

48 CFR 6.201 - Policy.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Policy. 6.201 Section 6.201 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION ACQUISITION PLANNING COMPETITION REQUIREMENTS Full and Open Competition After Exclusion of Sources 6.201 Policy. Acquisitions made...

48 CFR 201.301 - Policy.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Policy. 201.301 Section 201.301 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE GENERAL FEDERAL ACQUISITION REGULATIONS SYSTEM Agency Acquisition Regulations 201.301 Policy. (a...

14 CFR 135.201 - Applicability.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Applicability. 135.201 Section 135.201 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR CARRIERS... Limitations and Weather Requirements § 135.201 Applicability. This subpart prescribes the operating...

14 CFR 135.201 - Applicability.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Applicability. 135.201 Section 135.201 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR CARRIERS... Limitations and Weather Requirements § 135.201 Applicability. This subpart prescribes the operating...

14 CFR 135.201 - Applicability.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Applicability. 135.201 Section 135.201 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR CARRIERS... Limitations and Weather Requirements § 135.201 Applicability. This subpart prescribes the operating...

14 CFR 135.201 - Applicability.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Applicability. 135.201 Section 135.201 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR CARRIERS... Limitations and Weather Requirements § 135.201 Applicability. This subpart prescribes the operating...

14 CFR 135.201 - Applicability.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Applicability. 135.201 Section 135.201 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR CARRIERS... Limitations and Weather Requirements § 135.201 Applicability. This subpart prescribes the operating...

48 CFR 3424.201 - Authority.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 7 2010-10-01 2010-10-01 false Authority. 3424.201 Section 3424.201 Federal Acquisition Regulations System DEPARTMENT OF EDUCATION ACQUISITION REGULATION SOCIOECONOMIC PROGRAMS PROTECTION OF PRIVACY AND FREEDOM OF INFORMATION Freedom of Information Act 3424.201...

Electronic structure and dissociation curves for the ground states of Tl/sub 2/ and Tl/sub 2//sup +/ from relativistic effective potential calculations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Christiansen, P.A.; Pitzer, K.S.

The dissociation curves for the ground states of Tl/sub 2/ and Tl/sub 2//sup +/ were computed using a generalization of the molecular relativistic ..omega..--..omega.. coupling formalism of Lee, Ermler, and Pitzer. Relativistic effects, as represented by the Dirac equation, were introduced using effective potentials generated from atomic Dirac--nFock wave functions using a generalization of the improved effective potential formulation of Christiansen, Lee, and Pitzer. Our calculations show that the ground state of Tl/sub 2//sup +/ is 1/2/sub g/ with computed D/sub e/ and R/sub e/ values of 0.58 eV and 3.84 A. For Tl/sub 2/ we find that the groundmore » state is 0/sub u//sup -/ but the 0/sub g//sup +/ and the 1/sub u/ states are only slightly higher in energy; the potential curves for these states are repulsive to about 3.5 A and then essentially flat beyond that radius. While corrections for correlation will increase D/sub e/ somewhat, Tl/sub 2/ is only weakly bound in any of these states which dissociate to normal atoms. The cause is undoubtedly related to the large spin-orbit splitting between the 6p/sub 1/2/ and 6p/sub 3/2/ thallium spinors.« less

SANTPEN's SoTL Journey: Building and Using a SoTL Approach across Institutions

ERIC Educational Resources Information Center

West, Deborah; Stephenson, Helen

2016-01-01

In the current higher education environment, providing high quality teaching and learning experiences to students has moved beyond desirable to essential. Quality improvement takes many forms, but one core aspect to ensure sustainable improvement is the development of a culture of scholarship of teaching and learning (SoTL). Developing such an…

Method of forming superconducting Tl-Ba-Ca-Cu-O films

DOEpatents

Wessels, Bruce W.; Marks, Tobin J.; Richeson, Darrin S.; Tonge, Lauren M.; Zhang, Jiming

1993-01-01

A method of forming a superconducting Tl-Ba-Ca-Cu-O film is disclosed, which comprises depositing a Ba-Ca-Cu-O film on a substrate by MOCVD, annealing the deposited film and heat-treating the annealed film in a closed circular vessel with TlBa.sub.2 Ca.sub.2 Cu.sub.3 O.sub.x and cooling to form said superconducting film of TlO.sub.m Ba.sub.2 Ca.sub.n-1 Cu.sub.n O.sub.2n+2, wherein m=1,2 and n=1,2,3.

Branching ratios for TlBr photodissociation with 2660 A radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

White, J.C.; Zdasiuk, G.A.

1978-09-01

Radiation from a Nd:YAG laser was used to study the selective photodissociation of TlBr into the Tl metastable state, 6p/sup 2/P/sub 3/2/, as a potential candidate for stimulated Roman up-converters.(AIP)

14 CFR 415.201 - General.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false General. 415.201 Section 415.201 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH LICENSE Environmental Review § 415.201 General. An applicant shall provide the...

14 CFR 415.201 - General.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 4 2011-01-01 2011-01-01 false General. 415.201 Section 415.201 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH LICENSE Environmental Review § 415.201 General. An applicant shall provide the...

48 CFR 25.201 - Policy.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 48 Federal Acquisition Regulations System 1 2013-10-01 2013-10-01 false Policy. 25.201 Section 25.201 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION SOCIOECONOMIC PROGRAMS FOREIGN ACQUISITION Buy American Act-Construction Materials 25.201 Policy. Except as provided in 25.202...

48 CFR 1834.201 - Policy.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 48 Federal Acquisition Regulations System 6 2014-10-01 2014-10-01 false Policy. 1834.201 Section 1834.201 Federal Acquisition Regulations System NATIONAL AERONAUTICS AND SPACE ADMINISTRATION SPECIAL CATEGORIES OF CONTRACTING MAJOR SYSTEM ACQUISITION Earned Value Management System 1834.201 Policy. (a) NASA...

48 CFR 641.201 - Policy.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 48 Federal Acquisition Regulations System 4 2011-10-01 2011-10-01 false Policy. 641.201 Section 641.201 Federal Acquisition Regulations System DEPARTMENT OF STATE SPECIAL CATEGORIES OF CONTRACTING ACQUISITION OF UTILITY SERVICES Acquiring Utility Services 641.201 Policy. (d) The Procurement Executive is...

48 CFR 1834.201 - Policy.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 48 Federal Acquisition Regulations System 6 2012-10-01 2012-10-01 false Policy. 1834.201 Section 1834.201 Federal Acquisition Regulations System NATIONAL AERONAUTICS AND SPACE ADMINISTRATION SPECIAL CATEGORIES OF CONTRACTING MAJOR SYSTEM ACQUISITION Earned Value Management System 1834.201 Policy. (a) NASA...

48 CFR 24.201 - Authority.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Authority. 24.201 Section 24.201 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION SOCIOECONOMIC PROGRAMS PROTECTION OF PRIVACY AND FREEDOM OF INFORMATION Freedom of Information Act 24.201 Authority. The Freedom of...

42 CFR 66.201 - Applicability.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 42 Public Health 1 2011-10-01 2011-10-01 false Applicability. 66.201 Section 66.201 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES FELLOWSHIPS, INTERNSHIPS, TRAINING NATIONAL RESEARCH SERVICE AWARDS Institutional Grants § 66.201 Applicability. The regulations in this...

42 CFR 66.201 - Applicability.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 42 Public Health 1 2010-10-01 2010-10-01 false Applicability. 66.201 Section 66.201 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES FELLOWSHIPS, INTERNSHIPS, TRAINING NATIONAL RESEARCH SERVICE AWARDS Institutional Grants § 66.201 Applicability. The regulations in this...

42 CFR 66.201 - Applicability.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 42 Public Health 1 2012-10-01 2012-10-01 false Applicability. 66.201 Section 66.201 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES FELLOWSHIPS, INTERNSHIPS, TRAINING NATIONAL RESEARCH SERVICE AWARDS Institutional Grants § 66.201 Applicability. The regulations in this...

5 CFR 319.201 - Coverage.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 5 Administrative Personnel 1 2013-01-01 2013-01-01 false Coverage. 319.201 Section 319.201 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS EMPLOYMENT IN SENIOR-LEVEL AND SCIENTIFIC AND PROFESSIONAL POSITIONS Position Allocations and Establishment § 319.201 Coverage. This section...

5 CFR 319.201 - Coverage.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 5 Administrative Personnel 1 2011-01-01 2011-01-01 false Coverage. 319.201 Section 319.201 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS EMPLOYMENT IN SENIOR-LEVEL AND SCIENTIFIC AND PROFESSIONAL POSITIONS Position Allocations and Establishment § 319.201 Coverage. This section...

5 CFR 319.201 - Coverage.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 5 Administrative Personnel 1 2014-01-01 2014-01-01 false Coverage. 319.201 Section 319.201 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS EMPLOYMENT IN SENIOR-LEVEL AND SCIENTIFIC AND PROFESSIONAL POSITIONS Position Allocations and Establishment § 319.201 Coverage. This section...

5 CFR 319.201 - Coverage.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 5 Administrative Personnel 1 2012-01-01 2012-01-01 false Coverage. 319.201 Section 319.201 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS EMPLOYMENT IN SENIOR-LEVEL AND SCIENTIFIC AND PROFESSIONAL POSITIONS Position Allocations and Establishment § 319.201 Coverage. This section...

5 CFR 319.201 - Coverage.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Coverage. 319.201 Section 319.201 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS EMPLOYMENT IN SENIOR-LEVEL AND SCIENTIFIC AND PROFESSIONAL POSITIONS Position Allocations and Establishment § 319.201 Coverage. This section...

5 CFR 843.201 - Purpose.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 5 Administrative Personnel 2 2010-01-01 2010-01-01 false Purpose. 843.201 Section 843.201 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT (CONTINUED) CIVIL SERVICE REGULATIONS (CONTINUED) FEDERAL EMPLOYEES RETIREMENT SYSTEM-DEATH BENEFITS AND EMPLOYEE REFUNDS One-time Payments § 843.201 Purpose. This...

48 CFR 1313.201 - General.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false General. 1313.201 Section 1313.201 Federal Acquisition Regulations System DEPARTMENT OF COMMERCE CONTRACTING METHODS AND CONTRACT TYPES SIMPLIFIED ACQUISITION PROCEDURES Actions At or Below the Micro Purchase Threshold 1313.201...

Developing Scholarly Teachers through an SoTL Faculty Fellowship

ERIC Educational Resources Information Center

Fisher, Beth A.; Repice, Michelle D.; Dufault, Carolyn L.; Leonard, Denise A.; Frey, Regina F.

2014-01-01

The increasing interest in incorporating evidenced-based teaching in higher education has created a pronounced need for faculty to learn the theory and practice of the Scholarship of Teaching and Learning (SoTL). This article describes a program designed to prepare faculty to (a) draw on existing SoTL studies when designing and implementing…

Structural and superconducting features of Tl-1223 prepared at ambient pressure

DOE PAGES

Shipra, Fnu; Idrobo Tapia, Juan Carlos; Sefat, Athena Safa

2015-09-25

This study provides an account of the bulk preparation of TlBa 2Ca 2Cu 3O 9-δ (Tl-1223) superconductor at ambient pressure, and the Tc features under thermal-annealing conditions. The ‘as-prepared’ Tl-1223 (Tc =106 K) presents a significantly higher T c = 125 K after annealing the polycrystalline material in either flowing Ar+4% H 2, or N 2 gases. In order to understand the fundamental reasons for a particular Tc, we refined the average bulk structures using powder X-ray diffraction data. Although Ar+4%H2 annealed Tl- 1223 shows an increased ‘c’ lattice parameter, it shrinks by 0.03% (approximately unchanged) upon N2 anneal. Duemore » to such indeterminate conclusions on the average structural changes, local structures were investigated at using aberration-corrected scanning-transmission electron microscopy technique. Similar compositional changes in the atomic arrangements of both annealed-samples of Tl-1223 were detected in which the plane containing Ca atomic layer gives a non-uniform contrast, due to substitution of some heavier Tl. In this report, extensive bulk properties are summarized through temperature-dependent resistivity, and shielding and Meissner fractions of magnetic susceptibility results; the bulk and local structures are investigated to correlate to properties.« less

Soluble TL1A is sufficient for activation of death receptor 3.

PubMed

Bittner, Sebastian; Knoll, Gertrud; Füllsack, Simone; Kurz, Maria; Wajant, Harald; Ehrenschwender, Martin

2016-01-01

Death receptor 3 (DR3) is a typical member of the tumor necrosis factor receptor family, and was initially identified as a T-cell co-stimulatory molecule. However, further studies revealed a more complex and partly dichotomous role for DR3 and its ligand TL1A under (patho)physiological conditions. TL1A and DR3 are not only a driving force in the development of autoimmune and inflammatory diseases, but also play an important role in counteracting these processes through an increase in the number of regulatory T cells. Ligands of the tumor necrosis factor family typically occur in two forms, membrane-bound and soluble, that can differ strikingly with respect to their efficacy in activating their corresponding receptor(s). Ligand-based approaches to activate the TL1A-DR3 pathway therefore require understanding of the molecular prerequisites of TL1A-based DR3 activation. To date, this has not been addressed. Here, we show that recombinant soluble trimeric TL1A is fully sufficient to strongly activate DR3-associated pro- and anti-apoptotic signaling pathways. In contrast to the TRAIL death receptors, which are much better activated by soluble TRAIL upon secondary ligand oligomerization, but similarly to the death receptor tumor necrosis factor receptor 1, DR3 is efficiently activated by soluble TL1A trimers. Additionally, we have measured the affinity of TL1A-DR3 interaction in a cell-based system, and demonstrated TL1A-induced DR3 internalization. Identification of DR3 as a tumor necrosis factor receptor that responds to soluble ligand trimers without further oligomerization provides a basis for therapeutic exploitation of the TL1A-DR3 pathway. © 2015 FEBS.

Design of a digital phantom population for myocardial perfusion SPECT imaging research.

PubMed

Ghaly, Michael; Du, Yong; Fung, George S K; Tsui, Benjamin M W; Links, Jonathan M; Frey, Eric

2014-06-21

Digital phantoms and Monte Carlo (MC) simulations have become important tools for optimizing and evaluating instrumentation, acquisition and processing methods for myocardial perfusion SPECT (MPS). In this work, we designed a new adult digital phantom population and generated corresponding Tc-99m and Tl-201 projections for use in MPS research. The population is based on the three-dimensional XCAT phantom with organ parameters sampled from the Emory PET Torso Model Database. Phantoms included three variations each in body size, heart size, and subcutaneous adipose tissue level, for a total of 27 phantoms of each gender. The SimSET MC code and angular response functions were used to model interactions in the body and the collimator-detector system, respectively. We divided each phantom into seven organs, each simulated separately, allowing use of post-simulation summing to efficiently model uptake variations. Also, we adapted and used a criterion based on the relative Poisson effective count level to determine the required number of simulated photons for each simulated organ. This technique provided a quantitative estimate of the true noise in the simulated projection data, including residual MC simulation noise. Projections were generated in 1 keV wide energy windows from 48-184 keV assuming perfect energy resolution to permit study of the effects of window width, energy resolution, and crosstalk in the context of dual isotope MPS. We have developed a comprehensive method for efficiently simulating realistic projections for a realistic population of phantoms in the context of MPS imaging. The new phantom population and realistic database of simulated projections will be useful in performing mathematical and human observer studies to evaluate various acquisition and processing methods such as optimizing the energy window width, investigating the effect of energy resolution on image quality and evaluating compensation methods for degrading factors such as crosstalk

37 CFR 41.201 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 37 Patents, Trademarks, and Copyrights 1 2014-07-01 2014-07-01 false Definitions. 41.201 Section 41.201 Patents, Trademarks, and Copyrights UNITED STATES PATENT AND TRADEMARK OFFICE, DEPARTMENT OF COMMERCE PRACTICE BEFORE THE PATENT TRIAL AND APPEAL BOARD Patent Interferences § 41.201 Definitions. In...

46 CFR 107.201 - Purpose.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 4 2011-10-01 2011-10-01 false Purpose. 107.201 Section 107.201 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS INSPECTION AND CERTIFICATION Inspection and Certification § 107.201 Purpose. This subpart prescribes rules for the— (a) Original...

46 CFR 107.201 - Purpose.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 4 2014-10-01 2014-10-01 false Purpose. 107.201 Section 107.201 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS INSPECTION AND CERTIFICATION Inspection and Certification § 107.201 Purpose. This subpart prescribes rules for the— (a) Original...

46 CFR 107.201 - Purpose.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 4 2012-10-01 2012-10-01 false Purpose. 107.201 Section 107.201 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS INSPECTION AND CERTIFICATION Inspection and Certification § 107.201 Purpose. This subpart prescribes rules for the— (a) Original...

46 CFR 107.201 - Purpose.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Purpose. 107.201 Section 107.201 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS INSPECTION AND CERTIFICATION Inspection and Certification § 107.201 Purpose. This subpart prescribes rules for the— (a) Original...

46 CFR 107.201 - Purpose.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 4 2013-10-01 2013-10-01 false Purpose. 107.201 Section 107.201 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS INSPECTION AND CERTIFICATION Inspection and Certification § 107.201 Purpose. This subpart prescribes rules for the— (a) Original...

42 CFR 441.201 - Definition.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 42 Public Health 4 2010-10-01 2010-10-01 false Definition. 441.201 Section 441.201 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL ASSISTANCE PROGRAMS SERVICES: REQUIREMENTS AND LIMITS APPLICABLE TO SPECIFIC SERVICES Abortions § 441.201...

11 CFR 201.2 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 11 Federal Elections 1 2013-01-01 2012-01-01 true Definitions. 201.2 Section 201.2 Federal Elections FEDERAL ELECTION COMMISSION ADMINISTRATIVE REGULATIONS EX PARTE COMMUNICATIONS § 201.2 Definitions..., or (3) Any pending litigation matter, or (4) Any pending rulemaking, or (5) Any pending advisory...

11 CFR 201.2 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 11 Federal Elections 1 2011-01-01 2011-01-01 false Definitions. 201.2 Section 201.2 Federal Elections FEDERAL ELECTION COMMISSION ADMINISTRATIVE REGULATIONS EX PARTE COMMUNICATIONS § 201.2 Definitions..., or (3) Any pending litigation matter, or (4) Any pending rulemaking, or (5) Any pending advisory...

11 CFR 201.2 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 11 Federal Elections 1 2012-01-01 2012-01-01 false Definitions. 201.2 Section 201.2 Federal Elections FEDERAL ELECTION COMMISSION ADMINISTRATIVE REGULATIONS EX PARTE COMMUNICATIONS § 201.2 Definitions..., or (3) Any pending litigation matter, or (4) Any pending rulemaking, or (5) Any pending advisory...

19 CFR 201.12 - Requests.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 19 Customs Duties 3 2013-04-01 2013-04-01 false Requests. 201.12 Section 201.12 Customs Duties UNITED STATES INTERNATIONAL TRADE COMMISSION GENERAL RULES OF GENERAL APPLICATION Initiation and Conduct of Investigations § 201.12 Requests. Any party to a nonadjudicative investigation may request the...

19 CFR 201.12 - Requests.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 19 Customs Duties 3 2014-04-01 2014-04-01 false Requests. 201.12 Section 201.12 Customs Duties UNITED STATES INTERNATIONAL TRADE COMMISSION GENERAL RULES OF GENERAL APPLICATION Initiation and Conduct of Investigations § 201.12 Requests. Any party to a nonadjudicative investigation may request the...

47 CFR 201.0 - Background.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 47 Telecommunication 5 2013-10-01 2013-10-01 false Background. 201.0 Section 201.0 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL EXECUTIVE POLICY § 201.0 Background. National policy with respect to the conservation, allocation and use of the Nation's...

47 CFR 201.0 - Background.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 5 2011-10-01 2011-10-01 false Background. 201.0 Section 201.0 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL EXECUTIVE POLICY § 201.0 Background. National policy with respect to the conservation, allocation and use of the Nation's...

47 CFR 201.0 - Background.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Background. 201.0 Section 201.0 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL EXECUTIVE POLICY § 201.0 Background. National policy with respect to the conservation, allocation and use of the Nation's...

47 CFR 201.0 - Background.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 47 Telecommunication 5 2014-10-01 2014-10-01 false Background. 201.0 Section 201.0 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL EXECUTIVE POLICY § 201.0 Background. National policy with respect to the conservation, allocation and use of the Nation's...

47 CFR 201.0 - Background.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 47 Telecommunication 5 2012-10-01 2012-10-01 false Background. 201.0 Section 201.0 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL EXECUTIVE POLICY § 201.0 Background. National policy with respect to the conservation, allocation and use of the Nation's...

48 CFR 29.201 - General.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false General. 29.201 Section 29.201 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION GENERAL CONTRACTING REQUIREMENTS TAXES Federal Excise Taxes 29.201 General. (a) Federal excise taxes are levied on the sale or use...

42 CFR 441.201 - Definition.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 42 Public Health 4 2012-10-01 2012-10-01 false Definition. 441.201 Section 441.201 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL ASSISTANCE PROGRAMS SERVICES: REQUIREMENTS AND LIMITS APPLICABLE TO SPECIFIC SERVICES Abortions § 441.201...

42 CFR 441.201 - Definition.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 42 Public Health 4 2014-10-01 2014-10-01 false Definition. 441.201 Section 441.201 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL ASSISTANCE PROGRAMS SERVICES: REQUIREMENTS AND LIMITS APPLICABLE TO SPECIFIC SERVICES Abortions § 441.201...

42 CFR 441.201 - Definition.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 42 Public Health 4 2013-10-01 2013-10-01 false Definition. 441.201 Section 441.201 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL ASSISTANCE PROGRAMS SERVICES: REQUIREMENTS AND LIMITS APPLICABLE TO SPECIFIC SERVICES Abortions § 441.201...

42 CFR 441.201 - Definition.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 42 Public Health 4 2011-10-01 2011-10-01 false Definition. 441.201 Section 441.201 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL ASSISTANCE PROGRAMS SERVICES: REQUIREMENTS AND LIMITS APPLICABLE TO SPECIFIC SERVICES Abortions § 441.201...

37 CFR 41.201 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 37 Patents, Trademarks, and Copyrights 1 2010-07-01 2010-07-01 false Definitions. 41.201 Section 41.201 Patents, Trademarks, and Copyrights UNITED STATES PATENT AND TRADEMARK OFFICE, DEPARTMENT OF COMMERCE PRACTICE BEFORE THE BOARD OF PATENT APPEALS AND INTERFERENCES Patent Interferences § 41.201...

37 CFR 41.201 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 37 Patents, Trademarks, and Copyrights 1 2012-07-01 2012-07-01 false Definitions. 41.201 Section 41.201 Patents, Trademarks, and Copyrights UNITED STATES PATENT AND TRADEMARK OFFICE, DEPARTMENT OF COMMERCE PRACTICE BEFORE THE BOARD OF PATENT APPEALS AND INTERFERENCES Patent Interferences § 41.201...

32 CFR 724.201 - Authority.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 32 National Defense 5 2010-07-01 2010-07-01 false Authority. 724.201 Section 724.201 National Defense Department of Defense (Continued) DEPARTMENT OF THE NAVY PERSONNEL NAVAL DISCHARGE REVIEW BOARD Authority/Policy for Departmental Discharge Review § 724.201 Authority. The Naval Discharge Review Board...

5 CFR 752.201 - Coverage.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 5 Administrative Personnel 2 2014-01-01 2014-01-01 false Coverage. 752.201 Section 752.201 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT (CONTINUED) CIVIL SERVICE REGULATIONS (CONTINUED) ADVERSE ACTIONS Regulatory Requirements for Suspension for 14 Days or Less § 752.201 Coverage. (a) Adverse actions...

5 CFR 752.201 - Coverage.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 5 Administrative Personnel 2 2013-01-01 2013-01-01 false Coverage. 752.201 Section 752.201 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT (CONTINUED) CIVIL SERVICE REGULATIONS (CONTINUED) ADVERSE ACTIONS Regulatory Requirements for Suspension for 14 Days or Less § 752.201 Coverage. (a) Adverse actions...

5 CFR 752.201 - Coverage.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 5 Administrative Personnel 2 2012-01-01 2012-01-01 false Coverage. 752.201 Section 752.201 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT (CONTINUED) CIVIL SERVICE REGULATIONS (CONTINUED) ADVERSE ACTIONS Regulatory Requirements for Suspension for 14 Days or Less § 752.201 Coverage. (a) Adverse actions...

18 CFR 2.201 - [Reserved

Code of Federal Regulations, 2012 CFR

2012-04-01

... 18 Conservation of Power and Water Resources 1 2012-04-01 2012-04-01 false [Reserved] 2.201 Section 2.201 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY GENERAL RULES GENERAL POLICY AND INTERPRETATIONS Rules of General Applicability § 2.201...

18 CFR 2.201 - [Reserved

Code of Federal Regulations, 2013 CFR

2013-04-01

... 18 Conservation of Power and Water Resources 1 2013-04-01 2013-04-01 false [Reserved] 2.201 Section 2.201 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY GENERAL RULES GENERAL POLICY AND INTERPRETATIONS Rules of General Applicability § 2.201...

18 CFR 2.201 - [Reserved

Code of Federal Regulations, 2010 CFR

2010-04-01

... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false [Reserved] 2.201 Section 2.201 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY GENERAL RULES GENERAL POLICY AND INTERPRETATIONS Rules of General Applicability § 2.201...

18 CFR 2.201 - [Reserved

Code of Federal Regulations, 2014 CFR

2014-04-01

... 18 Conservation of Power and Water Resources 1 2014-04-01 2014-04-01 false [Reserved] 2.201 Section 2.201 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY GENERAL RULES GENERAL POLICY AND INTERPRETATIONS Rules of General Applicability § 2.201...

Measurements of myocardial flow vs. extraction of rubidium under varying physiological conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Budinger, T.F.; Yano, Y.; Moyer, B.R.

1984-01-01

The relationship between myocardial rubidium extraction (E) and flow (F) are well described by the single capillary model E = (1-exp(-PS/F)) with a permeability surface product PS = 0.87 cc/min/gm. Some effects of alkalosis and acidosis have been reported. Here the authors investigate the effects of dipyridamole, norepinephrine-atropine, exsanguination, pacing, ouabain and calcium on extraction using Rb-82 PET and Rb-86 acute studies with microspheres in dogs. Thoracotomies were performed for left atrial microsphere infusion. Anesthesia was by N/sub 2/O and methoxyflurane. The degree of exsanguination, drug levels administered and pacing rates were sufficient to produce flow modifications. Extraction was calculatedmore » by dividing FE from Rb observations by F from microsphere data. These results of extraction vs. flow do not show a significant dependence on the method used for flow modification. There was less than a 20% change in FE after an infusion of 0.04 mg/kg ouabain over 5 minutes in 3 replicate studies each on 4 dogs. An important finding not previously explained in flow vs. extraction studies is the occurrence of extraction values greater than 1.0 which is possible only if the distribution opportunities of small cations are greater than that of microspheres. This is equivalent to the well known hematocrit effect in small channels.« less

43 CFR 20.201 - Ethics officials.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 43 Public Lands: Interior 1 2011-10-01 2011-10-01 false Ethics officials. 20.201 Section 20.201... Department Ethics Program § 20.201 Ethics officials. (a) Designated Agency Ethics Official refers to the official designated under 5 CFR 2638.201 to coordinate and manage the Department's ethics program. (b) The...

43 CFR 20.201 - Ethics officials.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Ethics officials. 20.201 Section 20.201... Department Ethics Program § 20.201 Ethics officials. (a) Designated Agency Ethics Official refers to the official designated under 5 CFR 2638.201 to coordinate and manage the Department's ethics program. (b) The...

43 CFR 20.201 - Ethics officials.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 43 Public Lands: Interior 1 2014-10-01 2014-10-01 false Ethics officials. 20.201 Section 20.201... Department Ethics Program § 20.201 Ethics officials. (a) Designated Agency Ethics Official refers to the official designated under 5 CFR 2638.201 to coordinate and manage the Department's ethics program. (b) The...

43 CFR 20.201 - Ethics officials.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 43 Public Lands: Interior 1 2013-10-01 2013-10-01 false Ethics officials. 20.201 Section 20.201... Department Ethics Program § 20.201 Ethics officials. (a) Designated Agency Ethics Official refers to the official designated under 5 CFR 2638.201 to coordinate and manage the Department's ethics program. (b) The...

43 CFR 20.201 - Ethics officials.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 43 Public Lands: Interior 1 2012-10-01 2011-10-01 true Ethics officials. 20.201 Section 20.201... Department Ethics Program § 20.201 Ethics officials. (a) Designated Agency Ethics Official refers to the official designated under 5 CFR 2638.201 to coordinate and manage the Department's ethics program. (b) The...

48 CFR 45.201 - Solicitation.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Solicitation. 45.201 Section 45.201 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION CONTRACT MANAGEMENT GOVERNMENT PROPERTY Solicitation and Evaluation Procedures 45.201 Solicitation. (a) The contracting officer shall insert a listing of the Government...

7 CFR 25.201 - Application.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 1 2012-01-01 2012-01-01 false Application. 25.201 Section 25.201 Agriculture Office of the Secretary of Agriculture RURAL EMPOWERMENT ZONES AND ENTERPRISE COMMUNITIES Nomination Procedure § 25.201 Application. No rural area may be considered for designation pursuant to this part unless...

7 CFR 25.201 - Application.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 1 2013-01-01 2013-01-01 false Application. 25.201 Section 25.201 Agriculture Office of the Secretary of Agriculture RURAL EMPOWERMENT ZONES AND ENTERPRISE COMMUNITIES Nomination Procedure § 25.201 Application. No rural area may be considered for designation pursuant to this part unless...

7 CFR 25.201 - Application.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 1 2014-01-01 2014-01-01 false Application. 25.201 Section 25.201 Agriculture Office of the Secretary of Agriculture RURAL EMPOWERMENT ZONES AND ENTERPRISE COMMUNITIES Nomination Procedure § 25.201 Application. No rural area may be considered for designation pursuant to this part unless...

4 CFR 201.2 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 4 Accounts 1 2010-01-01 2010-01-01 false Definitions. 201.2 Section 201.2 Accounts RECOVERY ACCOUNTABILITY AND TRANSPARENCY BOARD PUBLIC INFORMATION AND REQUESTS § 201.2 Definitions. For words used in this document, unless the context indicates otherwise, singular includes the plural, plural includes the...

7 CFR 201.14 - Origin.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 3 2010-01-01 2010-01-01 false Origin. 201.14 Section 201.14 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.14 Origi...

7 CFR 201.11 - Type.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 3 2014-01-01 2014-01-01 false Type. 201.11 Section 201.11 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.11 Type. (...

7 CFR 201.10 - Variety.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 3 2011-01-01 2011-01-01 false Variety. 201.10 Section 201.10 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.10...

7 CFR 201.10 - Variety.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 3 2014-01-01 2014-01-01 false Variety. 201.10 Section 201.10 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.10...

7 CFR 201.20 - Germination.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 3 2012-01-01 2012-01-01 false Germination. 201.20 Section 201.20 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.20...

7 CFR 201.20 - Germination.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 3 2013-01-01 2013-01-01 false Germination. 201.20 Section 201.20 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.20...

7 CFR 201.20 - Germination.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 3 2011-01-01 2011-01-01 false Germination. 201.20 Section 201.20 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.20...

7 CFR 201.11 - Type.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 3 2010-01-01 2010-01-01 false Type. 201.11 Section 201.11 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.11 Type. (...

7 CFR 201.10 - Variety.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 3 2010-01-01 2010-01-01 false Variety. 201.10 Section 201.10 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.10...

7 CFR 201.14 - Origin.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 3 2014-01-01 2014-01-01 false Origin. 201.14 Section 201.14 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.14 Origi...

7 CFR 201.10 - Variety.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 3 2012-01-01 2012-01-01 false Variety. 201.10 Section 201.10 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.10...

7 CFR 201.14 - Origin.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 3 2011-01-01 2011-01-01 false Origin. 201.14 Section 201.14 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.14 Origi...

7 CFR 201.20 - Germination.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 3 2010-01-01 2010-01-01 false Germination. 201.20 Section 201.20 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.20...

7 CFR 201.11 - Type.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 3 2011-01-01 2011-01-01 false Type. 201.11 Section 201.11 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.11 Type. (...

7 CFR 201.14 - Origin.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 3 2012-01-01 2012-01-01 false Origin. 201.14 Section 201.14 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.14 Origi...

7 CFR 201.11 - Type.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 3 2013-01-01 2013-01-01 false Type. 201.11 Section 201.11 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.11 Type. (...

7 CFR 201.14 - Origin.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 3 2013-01-01 2013-01-01 false Origin. 201.14 Section 201.14 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.14 Origi...

7 CFR 201.20 - Germination.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 3 2014-01-01 2014-01-01 false Germination. 201.20 Section 201.20 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.20...

7 CFR 201.11 - Type.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 3 2012-01-01 2012-01-01 false Type. 201.11 Section 201.11 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.11 Type. (...

7 CFR 201.10 - Variety.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 3 2013-01-01 2013-01-01 false Variety. 201.10 Section 201.10 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.10...

7 CFR 25.201 - Application.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 1 2010-01-01 2010-01-01 false Application. 25.201 Section 25.201 Agriculture Office of the Secretary of Agriculture RURAL EMPOWERMENT ZONES AND ENTERPRISE COMMUNITIES Nomination Procedure § 25.201 Application. No rural area may be considered for designation pursuant to this part unless...

7 CFR 1260.201 - Reports.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 10 2012-01-01 2012-01-01 false Reports. 1260.201 Section 1260.201 Agriculture... Promotion and Research Order Reports, Books and Records § 1260.201 Reports. Each importer, person marketing... shall report to the Board periodically information required by regulations prescribed by the Board and...

7 CFR 1260.201 - Reports.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 10 2010-01-01 2010-01-01 false Reports. 1260.201 Section 1260.201 Agriculture... Promotion and Research Order Reports, Books and Records § 1260.201 Reports. Each importer, person marketing... shall report to the Board periodically information required by regulations prescribed by the Board and...

43 CFR 17.201 - Application.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Application. 17.201 Section 17.201 Public Lands: Interior Office of the Secretary of the Interior NONDISCRIMINATION IN FEDERALLY ASSISTED PROGRAMS OF THE DEPARTMENT OF THE INTERIOR Nondiscrimination on the Basis of Handicap § 17.201 Application...

7 CFR 25.201 - Application.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 1 2011-01-01 2011-01-01 false Application. 25.201 Section 25.201 Agriculture Office of the Secretary of Agriculture RURAL EMPOWERMENT ZONES AND ENTERPRISE COMMUNITIES Nomination Procedure § 25.201 Application. No rural area may be considered for designation pursuant to this part unless...

Pharmacological stress myocardial perfusion imaging with the potent and selective A(2A) adenosine receptor agonists ATL193 and ATL146e administered by either intravenous infusion or bolus injection.

PubMed

Glover, D K; Ruiz, M; Takehana, K; Petruzella, F D; Riou, L M; Rieger, J M; Macdonald, T L; Watson, D D; Linden, J; Beller, G A

2001-09-04

Adenosine (Ado) and dipyridamole are alternatives to exercise stress for myocardial perfusion imaging. Though generally safe, side effects frequently occur that cause patient discomfort and sometimes lead to premature termination of the study or require aminophylline administration. Recently, a new class of A(2A) Ado receptor agonists was synthesized. ATL193 and ATL146e are 2-propynylcyclohexyl-5'-N-ethylcarboxamido derivatives of Ado. The study goals were to evaluate the potency and selectivity of these new compounds on recombinant canine Ado receptors and to evaluate their hemodynamic properties in dogs to assess their usefulness as vasodilators for myocardial perfusion imaging. In assays of recombinant canine Ado receptors, ATL-193 and ATL-146e were highly selective for the A(2A) over the A(1) and A(3) receptors and were more potent than MRE-0470 and CGS-21680. In 16 anesthetized dogs, the agonists were administered by infusion (ATL-193; n=7 normal) or bolus injection (ATL-146e; n=9 critical left anterior descending coronary artery stenosis), and hemodynamic responses were compared with those of Ado. Both agonists produced dose-dependent coronary flow (CF) elevation without provoking the hypotension observed with Ado. After an ATL-146e bolus, the CF increase was sustained for several minutes, providing ample time for injection and myocardial uptake of (99m)Tc-sestamibi, and CF returned to baseline within 20 minutes. The CF increase was completely blocked by the selective A(2A) antagonist ZM241385 (3 microgram. kg(-1). min(-1)). ATL-193 and ATL-146e are highly potent and selective Ado A(2A) receptor agonists with excellent potential for use as vasodilators for myocardial perfusion imaging. An important advantage of ATL-146e is the ability to administer it by bolus injection.

7 CFR 201.42 - Small containers.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 3 2010-01-01 2010-01-01 false Small containers. 201.42 Section 201.42 Agriculture... REGULATIONS Sampling in the Administration of the Act § 201.42 Small containers. In sampling seed in small containers that it is not practical to sample as required in § 201.41, a portion of one unopened container or...

17 CFR 201.300 - Hearings.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 17 Commodity and Securities Exchanges 2 2013-04-01 2013-04-01 false Hearings. 201.300 Section 201... Practice Rules Regarding Hearings § 201.300 Hearings. Hearings for the purpose of taking evidence shall be held only upon order of the Commission. All hearings shall be conducted in a fair, impartial...

4 CFR 201.12 - Denials.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 4 Accounts 1 2010-01-01 2010-01-01 false Denials. 201.12 Section 201.12 Accounts RECOVERY ACCOUNTABILITY AND TRANSPARENCY BOARD PUBLIC INFORMATION AND REQUESTS § 201.12 Denials. (a) When denying a request in any respect, the Board shall notify the requestor of that determination in writing. The types...

5 CFR 2601.201 - Delegation.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 5 Administrative Personnel 3 2011-01-01 2011-01-01 false Delegation. 2601.201 Section 2601.201... § 2601.201 Delegation. (a) The authority to solicit, accept, and utilize gifts in accordance with this... in accordance with paragraph (b) of this section may be redelegated only through a written delegation...

5 CFR 2601.201 - Delegation.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 5 Administrative Personnel 3 2010-01-01 2010-01-01 false Delegation. 2601.201 Section 2601.201... § 2601.201 Delegation. (a) The authority to solicit, accept, and utilize gifts in accordance with this... in accordance with paragraph (b) of this section may be redelegated only through a written delegation...

28 CFR 31.201 - Audit.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 28 Judicial Administration 1 2010-07-01 2010-07-01 false Audit. 31.201 Section 31.201 Judicial Administration DEPARTMENT OF JUSTICE OJJDP GRANT PROGRAMS Formula Grants General Requirements § 31.201 Audit. The State must assure that it adheres to the audit requirements enumerated in the “Financial and...

47 CFR 201.3 - Policy.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 47 Telecommunication 5 2013-10-01 2013-10-01 false Policy. 201.3 Section 201.3 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL EXECUTIVE POLICY § 201.3 Policy. (a... and recovery. (g) The Director of the Office of Science and Technology Policy will serve as the...

47 CFR 201.3 - Policy.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 47 Telecommunication 5 2012-10-01 2012-10-01 false Policy. 201.3 Section 201.3 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL EXECUTIVE POLICY § 201.3 Policy. (a... and recovery. (g) The Director of the Office of Science and Technology Policy will serve as the...

47 CFR 201.3 - Policy.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 47 Telecommunication 5 2014-10-01 2014-10-01 false Policy. 201.3 Section 201.3 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL EXECUTIVE POLICY § 201.3 Policy. (a... and recovery. (g) The Director of the Office of Science and Technology Policy will serve as the...

47 CFR 201.3 - Policy.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 5 2011-10-01 2011-10-01 false Policy. 201.3 Section 201.3 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL EXECUTIVE POLICY § 201.3 Policy. (a... and recovery. (g) The Director of the Office of Science and Technology Policy will serve as the...

22 CFR 20.1 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 22 Foreign Relations 1 2011-04-01 2011-04-01 false Definitions. 20.1 Section 20.1 Foreign Relations DEPARTMENT OF STATE PERSONNEL BENEFITS FOR CERTAIN FORMER SPOUSES § 20.1 Definitions. As used in this part, unless otherwise specified, the following have the meaning indicated: COLA means cost-of...

22 CFR 20.1 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 22 Foreign Relations 1 2014-04-01 2014-04-01 false Definitions. 20.1 Section 20.1 Foreign Relations DEPARTMENT OF STATE PERSONNEL BENEFITS FOR CERTAIN FORMER SPOUSES § 20.1 Definitions. As used in this part, unless otherwise specified, the following have the meaning indicated: COLA means cost-of...

22 CFR 20.1 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 22 Foreign Relations 1 2012-04-01 2012-04-01 false Definitions. 20.1 Section 20.1 Foreign Relations DEPARTMENT OF STATE PERSONNEL BENEFITS FOR CERTAIN FORMER SPOUSES § 20.1 Definitions. As used in this part, unless otherwise specified, the following have the meaning indicated: COLA means cost-of...

22 CFR 20.1 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 22 Foreign Relations 1 2013-04-01 2013-04-01 false Definitions. 20.1 Section 20.1 Foreign Relations DEPARTMENT OF STATE PERSONNEL BENEFITS FOR CERTAIN FORMER SPOUSES § 20.1 Definitions. As used in this part, unless otherwise specified, the following have the meaning indicated: COLA means cost-of...

22 CFR 20.1 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Definitions. 20.1 Section 20.1 Foreign Relations DEPARTMENT OF STATE PERSONNEL BENEFITS FOR CERTAIN FORMER SPOUSES § 20.1 Definitions. As used in this part, unless otherwise specified, the following have the meaning indicated: COLA means cost-of...

5 CFR 300.201 - Examinations.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Examinations. 300.201 Section 300.201...) Examinations and Related Subjects § 300.201 Examinations. (a) The Office makes available information that will... examinations. This includes the types of questions and the categories of knowledge or skill pertinent to a...

7 CFR 201.9 - Kind.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 3 2012-01-01 2012-01-01 false Kind. 201.9 Section 201.9 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.9 Kind. The...

7 CFR 201.9 - Kind.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 3 2011-01-01 2011-01-01 false Kind. 201.9 Section 201.9 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.9 Kind. The...

7 CFR 201.9 - Kind.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 3 2014-01-01 2014-01-01 false Kind. 201.9 Section 201.9 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.9 Kind. The...

7 CFR 201.9 - Kind.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 3 2010-01-01 2010-01-01 false Kind. 201.9 Section 201.9 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.9 Kind. The...

7 CFR 201.9 - Kind.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 3 2013-01-01 2013-01-01 false Kind. 201.9 Section 201.9 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.9 Kind. The...

49 CFR 393.201 - Frames.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 5 2010-10-01 2010-10-01 false Frames. 393.201 Section 393.201 Transportation... SAFE OPERATION Frames, Cab and Body Components, Wheels, Steering, and Suspension Systems § 393.201 Frames. (a) The frame or chassis of each commercial motor vehicle shall not be cracked, loose, sagging or...

42 CFR 59.201 - Applicability.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 42 Public Health 1 2011-10-01 2011-10-01 false Applicability. 59.201 Section 59.201 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS GRANTS FOR FAMILY PLANNING SERVICES Grants for Family Planning Service Training § 59.201 Applicability. The regulations in this subpart are...

42 CFR 59.201 - Applicability.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 42 Public Health 1 2012-10-01 2012-10-01 false Applicability. 59.201 Section 59.201 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS GRANTS FOR FAMILY PLANNING SERVICES Grants for Family Planning Service Training § 59.201 Applicability. The regulations in this subpart are...

42 CFR 59.201 - Applicability.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 42 Public Health 1 2010-10-01 2010-10-01 false Applicability. 59.201 Section 59.201 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS GRANTS FOR FAMILY PLANNING SERVICES Grants for Family Planning Service Training § 59.201 Applicability. The regulations in this subpart are...

42 CFR 59.201 - Applicability.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 42 Public Health 1 2013-10-01 2013-10-01 false Applicability. 59.201 Section 59.201 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS GRANTS FOR FAMILY PLANNING SERVICES Grants for Family Planning Service Training § 59.201 Applicability. The regulations in this subpart are...

42 CFR 59.201 - Applicability.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 42 Public Health 1 2014-10-01 2014-10-01 false Applicability. 59.201 Section 59.201 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS GRANTS FOR FAMILY PLANNING SERVICES Grants for Family Planning Service Training § 59.201 Applicability. The regulations in this subpart are...

14 CFR 1214.201 - Definition.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Definition. 1214.201 Section 1214.201... the STS Program § 1214.201 Definition. For the purpose of this subpart, the term users means: (a) For... observer nations participating in Spacelab development, and Canada, when conducting experimental science or...

5 CFR 532.201 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-01-01

... establishments in the private sector by personal visit of data collectors. Host activity is the local Federal... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Definitions. 532.201 Section 532.201... Prevailing Rate Determinations § 532.201 Definitions. For the purposes of this part: Full-scale survey means...

48 CFR 13.201 - General.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false General. 13.201 Section 13.201 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION CONTRACTING METHODS AND CONTRACT TYPES SIMPLIFIED ACQUISITION PROCEDURES Actions at or Below the Micro-Purchase Threshold 13.201 General. (a) Agency heads are encouraged to...

Electromodulation spectroscopy of sc and fcc phase TlCl and TlBr

DOE Office of Scientific and Technical Information (OSTI.GOV)

McClelland, J.F.

1976-06-01

Electromodulation measurements were made on these compounds and the spectra were reduced to the electric field induced changes in the dielectric function. The results indicate the importance of photocarrier effects in both theory and experiment in the electromodulation of exciton states. In the future, calculations should include the effect of photocarriers on the field seen by the exciton and experimentally samples should be developed with known and reproducible photocarrier properties with temperature control between liquid helium and nitrogen temperatures and bipolar modulation fields. The abnormal (fcc) phase electroabsorption (EA) measurements have demonstrated the usefulness of the modulation method in resolvingmore » exciton states by determining the n = 2 energy in TlBr. This has enabled a number of quantities to be calculated from the Wannier exciton model. The resolution of the n = 2 energy in TlCl is probably also possible with an EA measurement and patience with the signal to noise problem. The ..cap alpha.. and ..beta.. features are still unassigned but the unusual EA lineshape and sample preparation sensitivity found in this investigation may prove useful in making definitive assignments in conjunction with future work.« less

Long-term room temperature stability of TlBr gamma detectors

NASA Astrophysics Data System (ADS)

Conway, A. M.; Voss, L. F.; Nelson, A. J.; Beck, P. R.; Graff, R. T.; Nikolic, R. J.; Payne, S. A.; Kim, H.; Cirignano, L. J.; Shah, K.

2011-09-01

TlBr is a material of interest for use in room temperature gamma ray detector applications due to is wide bandgap 2.7 eV and high average atomic number (Tl 81, Br 35). Researchers have achieved energy resolutions of 1.3 % at 662 keV, demonstrating the potential of this material system. However, these detectors are known to polarize using conventional configurations, limiting their use. Continued improvement of room temperature, high-resolution gamma ray detectors based on TlBr requires further understanding of the degradation mechanisms. While high quality material is a critical starting point for excellent detector performance, we show that the room temperature stability of planar TlBr gamma spectrometers can be significantly enhanced by treatment with both hydrofluoric and hydrochloric acid. By incorporating F or Cl into the surface of TlBr, current instabilities are eliminated and the longer term current of the detectors remains unchanged. 241Am spectra are also shown to be more stable for extended periods; detectors have been held at 2000 V/cm for 52 days with less than 10% degradation in peak centroid position. In addition, evidence for the long term degradation mechanism being related to the contact metal is presented.

Personal Reflection: Lessons from My Students and Other Reflections on SoTL

ERIC Educational Resources Information Center

McKinney, Kathleen

2009-01-01

This personal reflection describes the author's 25-year relationship with the scholarship of teaching and learning. Her thoughts wander to influences on her career in SoTL, the impact SoTL has had on her professional life, the dilemmas in the field that continue to be pondered, ways to advocate for and support SoTL work, and her hopes for the…

Tl2LiYCl6 (Ce3+): New Tl-based Elpasolite Scintillation Material

NASA Astrophysics Data System (ADS)

Kim, H. J.; Rooh, Gul; Park, H.; Kim, Sunghwan

2016-04-01

New single crystals of Ce-doped (1% and 10%) Tl2LiYCl6 (TLYC) were investigated under X-ray and -y-ray excitation. This material belongs to Chloro-elpasolite crystal family and was grown by the two-zone vertical Bridgman technique. X-ray-induced luminescence shows typical Ce3+ - ion emission between 350 and 530 nm peaking at 430 nm. Under 662 keV -y-rays excitation, best energy resolution of 4.8% (FWHM) was found for 1% Ce-concentration. For the same Ce-concentration, a maximum light yield of 30 500 ± 3500 ph/MeV was observed at room temperature. Under -y-ray excitation, three decay time components were observed for all Ce-doped samples. Effective Z-number and density of Tl2LiYCl6 were found to be 69 and 4.58 g/cm3, respectively. Due to highly hygroscopic nature of this compound, extra attention was devoted during handling and data taking processes. Overall, the scintillation properties confirm that this material is a promising candidate for medical imaging and radiation detection.

10 CFR 26.201 - Applicability.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 1 2011-01-01 2011-01-01 false Applicability. 26.201 Section 26.201 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Managing Fatigue § 26.201 Applicability. The requirements in this subpart apply to the licensees and other entities identified in § 26.3(a), and, if applicable, (c...

10 CFR 26.201 - Applicability.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false Applicability. 26.201 Section 26.201 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Managing Fatigue § 26.201 Applicability. The requirements in this subpart apply to the licensees and other entities identified in § 26.3(a), and, if applicable, (c...

10 CFR 26.201 - Applicability.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 1 2012-01-01 2012-01-01 false Applicability. 26.201 Section 26.201 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Managing Fatigue § 26.201 Applicability. The requirements in this subpart apply to the licensees and other entities identified in § 26.3(a), and, if applicable, (c...

10 CFR 26.201 - Applicability.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 1 2014-01-01 2014-01-01 false Applicability. 26.201 Section 26.201 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Managing Fatigue § 26.201 Applicability. The requirements in this subpart apply to the licensees and other entities identified in § 26.3(a), and, if applicable, (c...

10 CFR 26.201 - Applicability.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 1 2013-01-01 2013-01-01 false Applicability. 26.201 Section 26.201 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Managing Fatigue § 26.201 Applicability. The requirements in this subpart apply to the licensees and other entities identified in § 26.3(a), and, if applicable, (c...

48 CFR 613.201 - General.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 4 2010-10-01 2010-10-01 false General. 613.201 Section 613.201 Federal Acquisition Regulations System DEPARTMENT OF STATE CONTRACTING METHODS AND CONTRACT TYPES SIMPLIFIED ACQUISITION PROCEDURES Actions At or Below the Micro-Purchase Threshold 613.201 General. (g)(1) The procurement Executive is the...

Oxidation/reduction reactions at the metal contact-TlBr interface: an x-ray photoelectron spectroscopy study

NASA Astrophysics Data System (ADS)

Nelson, A. J.; Swanberg, E. L.; Voss, L. F.; Graff, R. T.; Conway, A. M.; Nikolic, R. J.; Payne, S. A.; Kim, H.; Cirignano, L.; Shah, K.

2014-09-01

TlBr radiation detector operation degrades with time at room temperature and is thought to be due to electromigration of Tl and Br vacancies within the crystal as well as the metal contacts migrating into the TlBr crystal itself due to electrochemical reactions at the metal/TlBr interface. X-ray photoemission spectroscopy (XPS) was used to investigate the metal contact surface/interfacial structure on TlBr devices. Device-grade TlBr was polished and subjected to a 32% HCl etch to remove surface damage prior to Mo or Pt contact deposition. High-resolution photoemission measurements on the Tl 4f, Br 3d, Cl 2p, Mo 3d and Pt 4f core lines were used to evaluate surface chemistry and non-equilibrium interfacial diffusion. Results indicate that anion substitution at the TlBr surface due to the HCl etch forms TlBr1-xClx with consequent formation of a shallow heterojunction. In addition, a reduction of Tl1+ to Tl0 is observed at the metal contacts after device operation in both air and N2 at ambient temperature. Understanding contact/device degradation versus operating environment is useful for improving radiation detector performance.

Experimental Determination of the Ionization Energy in TlBr

NASA Astrophysics Data System (ADS)

Hitomi, Keitaro; Onodera, Toshiyuki; Kim, Seong-Yun; Shoji, Tadayoshi; Ishii, Keizo

2015-06-01

The average ionization energy required to excite an electron-hole pair in TlBr was estimated to be 5.50 ± 0.05 eV by comparing the peak position of 59.5-keV gamma rays obtained from four pixels of a pixelated TlBr detector to the peak position obtained from a Si PIN photodiode at room temperature.

Ultrasonic and elastic properties of Tl- and Hg-Based cuprate superconductors: a review

NASA Astrophysics Data System (ADS)

Abd-Shukor, R.

2018-01-01

This review is regarding the ultrasonic and elastic properties of Tl- and Hg-based cuprate superconductors. The objectives of this paper were to review the ultrasonic attenuation above the transition temperature ?, and sound velocity and elastic anomalies at ? in the Tl- and Hg-based cuprate superconductors. A discontinuity in the sound velocity and elastic moduli is observed near ? for the Hg-based and other cuprate high temperature superconductor but not the Tl-based superconductor. Ultrasonic attenuation peaks are observed between 200 and 250 K in almost all Tl- and Hg-based cuprate superconductors reported. These peaks were attributed to lattice stepping and oxygen ordering in the Tl-O and Hg-O layers. Some Tl- and Hg-based superconductors show attenuation peak near ?. However, this is not a common feature for the cuprate superconductors. The ultrasonic attenuation decrease rate below ? is slower than that expected from a Bardeen-Cooper-Schrieffer (BCS) and pseudo-gapped superconductor.

Biochemical and Structural Characterization of the Human TL1A Ectodomain†¶

PubMed Central

Zhan, Chenyang; Yan, Qingrong; Patskovsky, Yury; Li, Zhenhong; Toro, Rafael; Meyer, Amanda; Cheng, Huiyong; Brenowitz, Michael; Nathenson, Stanley G; Almo, Steven C

2009-01-01

TNF-like 1A (TL1A) is a newly described member of the TNF superfamily that is directly implicated in the pathogenesis of autoimmune diseases, including inflammatory bowel disease, atherosclerosis and rheumatoid arthritis. We report the crystal structure of the human TL1A extracellular domain at a resolution of 2.5 Å, which reveals a jelly-roll fold typical of the TNF superfamily. This structural information, in combination with complementary mutagenesis and biochemical characterization, provides insights into the binding interface and the specificity of the interactions between TL1A and the DcR3 and DR3 receptors. These studies suggest that the mode of interaction between TL1A and DcR3 differs from other characterized TNF ligand/receptor complexes. In addition, we have generated functional TL1A mutants with altered disulfide bonding capability that exhibit enhanced solution properties, which will facilitate the production of materials for future cell-based and whole animal studies. In summary, these studies provide insights into the structure and function of TL1A and provide the basis for the rational manipulation of its interactions with cognate receptors. PMID:19522538

17 CFR 201.54 - Settlement.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 17 Commodity and Securities Exchanges 2 2010-04-01 2010-04-01 false Settlement. 201.54 Section 201... Regulations Pertaining to the Equal Access to Justice Act § 201.54 Settlement. The applicant and counsel for the Office or Division of the Commission may agree on a proposed settlement of the award before final...

4 CFR 201.14 - Appeals.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 4 Accounts 1 2010-01-01 2010-01-01 false Appeals. 201.14 Section 201.14 Accounts RECOVERY ACCOUNTABILITY AND TRANSPARENCY BOARD PUBLIC INFORMATION AND REQUESTS § 201.14 Appeals. (a)(1) Appeals of adverse... response. The appeal letter, e-mail or fax may include as much or as little related information as you wish...

4 CFR 201.1 - Scope.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 4 Accounts 1 2010-01-01 2010-01-01 false Scope. 201.1 Section 201.1 Accounts RECOVERY ACCOUNTABILITY AND TRANSPARENCY BOARD PUBLIC INFORMATION AND REQUESTS § 201.1 Scope. This part sets forth the... access to documents under the Freedom of Information Act (FOIA or the Act), 5 U.S.C. 552. The provisions...

4 CFR 201.8 - Fees.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 4 Accounts 1 2010-01-01 2010-01-01 false Fees. 201.8 Section 201.8 Accounts RECOVERY ACCOUNTABILITY AND TRANSPARENCY BOARD PUBLIC INFORMATION AND REQUESTS § 201.8 Fees. (a) General. The Board shall...—A request from, or on behalf of, a person who seeks information for a purpose that furthers his/her...

10 CFR 800.201 - Findings.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 4 2010-01-01 2010-01-01 false Findings. 800.201 Section 800.201 Energy DEPARTMENT OF... ASSISTANCE Loans § 800.201 Findings. A loan shall issue under this regulation only if the Secretary, having... the Secretary may deem pertinent, has made all the findings that follow: (a) That the applicant is a...

Study on Effects of Gamma-Ray Irradiation on TlBr Semiconductor Detectors

NASA Astrophysics Data System (ADS)

Matsumura, Motohiro; Watanabe, Kenichi; Yamazaki, Atsushi; Uritani, Akira; Kimura, Norihisa; Nagano, Nobumichi; Hitomi, Keitaro

Radiation hardness of thallium bromide (TlBr) semiconductor detectors to 60Co gamma-ray irradiation was evaluated. The energy spectra and μτ products of electrons were measured to evaluate the irradiation effects. No significant degradation of spectroscopic performance of the TlBr detector for 137Cs gamma-rays was observed up to 45 kGy irradiation. Although the μτ products of electrons in the TlBr detector slightly decreased, position of the photo-peak was stable without significant degradation after the gamma-ray irradiation. We confirmed that the TlBr semiconductor detector has a high tolerance for gamma-ray irradiation at least up to 45 kGy.

Thermal and magnetic characterisation of (Co0.402Fe0.201Ni0.067B0.227Si0.053Nb0.05)100-xCux bulk metallic glasses

NASA Astrophysics Data System (ADS)

Sarlar, Kagan; Kucuk, Ilker

2017-03-01