A model for bifurcation regions of the human tracheo-bronchial tree was developed. Equations for the surfaces are given to enable calculations of doses from alpha-particles emitted in these regions. It has been found that a bifurcation region is well approximated by a quasi-ellipsoid. The absorbed fractions of alpha-particles emitted in bifurcation regions were calculated by the Monte Carlo met...

Context. Aims. Intrinsic absorption is a fundamental physical property to understand the evolution of active galactic nuclei (AGN). Here a sample of 1290 AGN, selected in the 2–10 keV band from different flux-limited surveys with very high optical identification completeness is studied. Methods. The AGN are grouped into two classes, unabsorbed (type-1) and absorbed (type-2), depending on their ...

abstract objective cardiac dysfunction is a major cause of death in patients with beta thalassemia. in these patients, repeated blood transfusion, ineffective erythropoiesis and increased gastrointestinal iron absorption lead to iron overload in the body and this induced heart failure. left ventricular ejection fraction was measured in major beta thalassemia (β-th) patients to detect the relati...

Lethal effects of thermal neutrons were compared with those of 60Co-ƒÁ-rays on the two types of Amoeba proteus. D37 doses against ƒÁ-rays were 2.5 •~ 105 (M-type) and 7.2 •~ 105 rads (P type), and those for thermal neutrons were 9.1 and 11.7 •~ 1013 n. cm-2 (total flux) respectively. Additions of AET, D2O or boron failed to increase or decrease the lethal effects of thermal neutrons. The lethal...