Determination of 226Ra Contamination Depth Around Phosphogypsum Pit Using In-Situ Gamma Spectrometer.

The feasibility of applying multiple photopeak method (MPM) and peak to valley ratio (PVRM) method to determine Radium-226 contamination depth (226Ra hc) has been investigated. Gamma spectra in eight positions around phosphogypsum disposal pit has been measured using portable NaI(Tl) gamma spectrometer. MPM was investigated by calculating the ratio [Formula: see text] of 609 keV gamma line net counts to the corresponding value of 352 keV. PVRM was investigated by calculating the ratio [Formula: see text] of net counts of 609 keV gamma line to the corresponding valley counts. 226Ra hc in the positions has been determined using traditional soil coring. It was found that, [Formula: see text] and [Formula: see text] have good linear correlations with 226Ra hcTherefore, 226Ra hc can be determined by MPM and PVRM. These methods save a lot of time, costs and efforts in comparison with the traditional one.

Assessment of soil contamination by (210)Po and (210)Pb around heavy oil and natural gas fired power plants.

Soil contamination by (210)Pb and (210)Po around heavy oil and natural gas power plants has been investigated; fly and bottom ash containing enhanced levels of (210)Pb and (210)Po were found to be the main source of surface soil contamination. The results showed that (210)Pb and (210)Po in fly-ash (economizer, superheater) is highly enriched with (210)Pb and (210)Po, while bottom-ash (boiler) is depleted. The highest (210)Pb and (210)Po activity concentrations were found to be in economizer ash, whereas the lowest activity concentration was in the recirculator ash. On the other hand, (210)Pb and (210)Po activity concentrations in soil samples were found to be higher inside the plant site area than those samples collected from surrounding areas. The highest levels were found in the vicinity of Mhardeh and Tishreen power plants; both plants are operated by heavy oil and natural fuels, while the lowest values were found to be in those samples collected from Nasrieh power plant, which is only operated by one type of fuel, viz. natural gas. In addition, the levels of surface soil contamination have decreased as the distance from the power plant site center increased.

Group A beta-haemolytic streptococcal infection and Henoch-Schonlein purpura with cardiac, renal and neurological complications.

A 6-year-old girl had a group A beta-haemolytic streptococcal (GABS) throat infection and Henoch-Schonlein purpura (HSP). The clinical course was complicated by nephrotic syndrome due to crescentic glomerulonephritis, transient neurological symptoms due to focal ischaemia of the brain, and congestive cardiac failure due to myocarditis. The clinical presentation highlights the diversity of systemic involvement in HSP, the transient nature of apparently serious central nervous system involvement, and a possible role of GABS in its aetiology.

A comparison of left ventricular volumes and regurgitant fraction by Doppler echocardiography and angiography in children.

Regurgitant fraction calculations by echocardiography were compared to angiocardiography in 11 patients with mitral regurgitation. Although there was a very good correlation when compared with angiocardiography (r = 0.99, SEE: 6.26, P < 0.001), two-dimensional echocardiography underestimated left ventricular end-diastolic volumes (P < 0.05). The mean regurgitant fraction was 36.2 +/- 13.5% by echocardiography and 43.6 +/- 15.7% (P < 0.05) by angiography. Most of the variability in measuring the regurgitant fraction is attributed to the left ventricular volume measurements. In conclusion, regurgitant fraction calculations of mitral regurgitation by echocardiography compares favorably to angiography. Since the severity of mitral regurgitation is an important determinant of prognosis, quantification of the regurgitant fraction may be useful in the long term follow-up of those patients.

Acute hemodynamic effects of adjustable atrial septal defect closure in the lateral tunnel Fontan procedure.

OBJECTIVES: This study evaluated the acute hemodynamic changes with atrial septal defect closure in the postoperative period in patients undergoing the Fontan procedure. BACKGROUND: The adjustable atrial septal defect is a modification of the Fontan procedure designed to improve cardiac output and reduce systemic venous hypertension during the postoperative period. Limited information is available on the effects of inter-atrial shunting on the physiology of direct cavopulmonary connection. METHODS: In 11 patients (aged 9 months to 14.5 years), the atrial septal defect was closed 8 h to 4.6 days (mean 1.7 days) postoperatively. Indications for closure included mean right atrial pressure < 15 mm Hg or arterial oxygen saturation < 80%, or both. RESULTS: Data presented are mean values +/- 1 SD. Mean right atrial pressure was 13.4 +/- 3.0 mm Hg on admission to the intensive care unit, 10.0 +/- 2.0 mm Hg (p = 0.02) immediately before closure and 11.4 +/- 2.8 mm Hg (p = 0.02) after closure. There was a significant decrease in cardiac output, as calculated from arteriovenous oxygen saturation difference (26 +/- 9%, p = 0.003), Doppler aortic flow (19 +/- 9%, p = 0.0002) and ventricular volumes by two-dimensional echocardiography (20 +/- 8%, p = 0.0001). Arterial oxygen saturation increased from 82 +/- 5% to 94 +/- 4% (p = 0.0001), and arteriovenous oxygen saturation difference increased from 25 +/- 8% to 33 +/- 9% (p = 0.0001). Systemic oxygen delivery decreased from 727 +/- 354 to 655 +/- 325 ml/min per m2 (p = 0.02). One patient required reopening of the atrial septal defect. CONCLUSIONS: These data demonstrate that a controlled right to left atrial shunt improves cardiac output and systemic oxygen delivery and facilitates the postoperative management of patients after the Fontan procedure. Atrial septal defect closure increases systemic saturation to normal values and prevents potential systemic embolization but significantly decreases oxygen delivery and might limit exercise tolerance.