UNCLASSIFIED a given degree of injury than for X rays, and thus thermal neutrons give great promise as a tool for genetic study. Use of phosphorus 32 in sickle-cell anemia. Sicklefcell anemia, a serious blood disorder in which red blood cells assume anfabnormal sickle shape, affects approximately one in 500 Negro children infthe United States. Under a project with Howard University, a study Is being made of blood from victims of this disease not only to increase understanding of this condition but also to obtain information concernigg protein syn- thesis and the dynamics of phosphorus transfer in the blogd. Investiga- tors in the use of phosphorus 32 haveshown that. phosphat@ exchanges across the red blood cell membrane are at a slower rate ig sickle cells than in normal cells. The alkaline phospmtase in sickle-#ell anemia plasma is significantly higher than that in normal plasma. Iitial studies on phosphate transfer using metabolic inhibitors indicate]the absence of @ certain enzyme from the sickle-cell anemia blood. One @f the most significant observations of this group on the problem is tha} one of the protein components of the plasma has a different mobilityJas determined by electrophoresis. This finding is being investigated f¥rther with additional electrophoresis equipment and under varying expeJimental con- ditions. This work complements other investigations in which of hemoglobin in sickle cells is found to be different fr mal cells. Shielding studies. The problem of providing adequa personnel protection in equipment designed for radiation ources must be coupled with that of economies in operation. For lower e ergy ranges, shielding is not an expensive factor. However, in the us of higher intensity radiations, the problem of personnel protection i volves high expenditures. This problem is being investigated under a cooperative project with the National Bureau of Standards to determin design factors of various types of equipment in which savings might be r alized, and at the same time to determine with greater accuracy the validity of former assumptions so that more reliable calculations may be madq@ in shielding design. The present work is concerned with the ‘attenuatidn characteristics of a shield when the rays from the source enter the ghield obliquely. To a first approximation, the effective thickness of the ghield has been assumed to be the length of path of the ray in the shield]J-—that is, the more oblique the direction of incidence, the longer the path and the greater the degree of shielding. In this study it has bedn shown that while oblique thickness of the barrier may be utilized infdesigning equipment to shield against the primary rays, the contributionfof scattered radiation from within the shield may become appreciable. [Scattered radiation increases significantly as the obliquity of the incident ray increases, because of the shorter path length for a number of thd scattered rays. Data obtained from these investigations will be appJicable to the design of protective shielding for personnel operating cydlotrons, Van de Graaff generators, or handling cobalt 60 and radium sourcds which are used 12 UNCLASSIFIuD DOE JARCHIVES