14 research outputs found

    A Multiple Case Study Examining the Challenges and Successes in the Development and Implementation of Transition and Post-secondary Education Programs for Students with Intellectual Disabilities

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    The purpose of this multiple case study was to examine the successes, challenges, and factors identified to mitigate or overcome the identified challenges, as experienced by program directors, faculty, and staff, in the development and implementation of transition and post-secondary education programs, for students identified with intellectual disability at 4-year post-secondary educational institutions. Theories guiding this study were program implementation theory (Weiss, 1997) and disability theory (Mertens, 2009). Sites included three transition and post-secondary education programs for students with intellectual disability, utilizing similarly designed program models at a four-year post-secondary institution. Multiple forms of data collected from each site included participant surveys, interviews, observations, focus group, program related documents, and public information retrieved from social media and institutional web sites were analyzed through in-case and across-case analyses. The study revealed the need for strategic planning to identify the most appropriate program model to ensure sustainability of the program, including planning for funding, staffing, development of policies and procedures, and student admission, prior to student admission in the program. In addition, this study revealed the need for commitment, flexibility, and collaboration among program directors, faculty, and staff to meet the ever changing and fluid environment in serving students within a transition and post-secondary education program for students with ID. Further study is needed to identify best practices in student selection processes, programmatic policies, curriculum, and sustainable funding sources

    Ion exchange behavior among metal trisilicates: probing selectivity, structures, and mechanism

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    One model system for the investigation of selectivity in inorganic ion exchangers is a group of synthetic analogues of the mineral umbite. Hydrothermally synthesized trisilicates with the general form A2BSi3O9.H2O, where A is a monovalent cation, and B = Ti4+, Zr4+, and Sn4+ have been shown to have ion exchange properties. The extended three dimensional framework structure offers the ability to tune the selectivity based on the size of the cavities and channels. The unit cell volume, and therefore the pore size, can be altered by changing the size of the octahedral metal. The substitution of Ge for Si can also increase the pore size. A variety of cations have been exchanged into the trisilicates including alkali and alkaline earths, lanthanides, and actinides. The reason for the selectivity rests in the pocket of framework oxygens which make up the exchange sites. Close examination of the cation environments shows that the ions with the greatest affinity are those that have the closest contacts to the framework oxygens. For example, among alkali cations, zirconium trisilicate demonstrates the greatest affinity for Rb+ and has the most A-O contact distances approaching the sum of their ionic radii. The origins of selectivity also rely upon the valence of the incoming cation. When cations are of similar ionic radius, a cation of higher charge is always preferred over the lower valence. Ion exchange studies in binary solutions of cations of different valence, but similar size (1.0Å ) have proven the selectivity series to be Th4+ > Gd3+ > Ca2+ > Na+. Through structural characterization, kinetic studies, and use of in situ x-ray diffraction techniques the origins of selectivity in these inorganic ion exchangers has been further elucidated. The principles gleaned from these studies can be applied to other inorganic framework materials. The umbite system has the potential to be altered and tailored for specific separation needs. The trisilicate materials presented in this work are representative of the types of advances in inorganic materials research and prove their potential as applicable compounds useful for solving real world problems

    A microporous titanosilicate for selective killing of HeLa cancer cells

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    Structural distribution of zinc(II) ions in the pore system of three silicate molecular sieves has revealed an unprecedented application of the microporous titanosilicate Zn-ETS-4 as a non toxic, highly efficient and selective inhibitor of HeLa cancer cells
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