Increasing mentally retarded adolescents' verbalizations about current events

The effects of antecedent and consequent events on the verbal behavior of three institutionalized mentally retarded adolescents were examined. Verbal statements, related to current national and international events, were recorded after exposures to television news programs. The study examined the accuracy of verbalizations as a function of: (1) exposures to television news presentations in massed (i.e., viewing the entire news program before an opportunity to describe it) versus distributed from (i.e., viewing each news item separately with each followed by an opportunity to describe it), and (2) contingent tokens and social praise for correct verbal responses (i.e., statements corresponding to news items presented). Both the temporal distribution of news presentations and the reinforcement procedures improved the accuracy of verbal statements emitted by the subjects

Synthesis of multiarm star copolymers based on polyglycerol cores with polylactide arms and their application as nanocarriers

Hyperbranched polyglycerol (hPG) with two different molecular weights (hPG2400 and hPG8000) was used as a macroinitiator for the polymerization of lactide. Thereby, amphiphilic linear-dendritic multiarm star copolymers (MSCs) were prepared and investigated with regard to their ability to encapsulate and transport guest molecules. Various ratios of monomer to hydroxy functional end groups ([LA]/[OH]) were used for the preparation of linear-dendritic multiarm copolymers with different degrees of polymerization (DP), molecular weight, and arm multiplicity. At high molecular weights almost all of the hydroxy groups of hPG were reacted with the lactide monomer and the number of arms was equal to the number of hydroxy functional groups. The ability of the synthesized MSCs to encapsulate and transport small guest molecules was examined. The transport capacity (TC) of all nanocarriers under different conditions was investigated using the model dye Congo red as well as the model drug 5-aminosalicylic acid (5-ASA). With both hPG2400 and hPG8000 cores, the TC increased along with an increasing number and length of the arms. The dependence of the TC on the concentration of MSCs was also investigated and found to deteriorate with increasing polymer concentration. Finally the ability of the synthesized nanocarriers to penetrate into the skin and transport Nile red through this barrier was successfully investigated