4,468 research outputs found

    Provision Of Carbon Nanotube Bucky Paper Cages For Immune Shielding Of Cells, Tissues, and Medical Devices

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    System and method for enclosing cells and/or tissue, for purposes of growth, cell differentiation, suppression of cell differentiation, biological processing and/or transplantation of cells and tissues (biological inserts), and for secretion, sensing and monitoring of selected chemical substances and activation of gene expression of biological inserts implanted into a human body. Selected cells and/or tissue are enveloped in a "cage" that is primarily carbon nanotube Bucky paper, with a selected thickness and porosity. Optionally, selected functional groups, proteins and/or peptides are attached to the carbon nanotube cage, or included within the cage, to enhance the growth and/or differentiation of the cells and/or tissue, to select for certain cellular sub-populations, to optimize certain functions of the cells and/or tissue and/or to optimize the passage of chemicals across the cage surface(s). A cage system is also used as an immuns shield and to control operation of a nano-device or macroscopic device, located within the cage, to provide or transform a selected chemical and/or a selected signal

    Narrow Line Cooling and Momentum-Space Crystals

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    Narrow line laser cooling is advancing the frontier for experiments ranging from studies of fundamental atomic physics to high precision optical frequency standards. In this paper, we present an extensive description of the systems and techniques necessary to realize 689 nm 1S0 - 3P1 narrow line cooling of atomic 88Sr. Narrow line cooling and trapping dynamics are also studied in detail. By controlling the relative size of the power broadened transition linewidth and the single-photon recoil frequency shift, we show that it is possible to continuously bridge the gap between semiclassical and quantum mechanical cooling. Novel semiclassical cooling process, some of which are intimately linked to gravity, are also explored. Moreover, for laser frequencies tuned above the atomic resonance, we demonstrate momentum-space crystals containing up to 26 well defined lattice points. Gravitationally assisted cooling is also achieved with blue-detuned light. Theoretically, we find the blue detuned dynamics are universal to Doppler limited systems. This paper offers the most comprehensive study of narrow line laser cooling to date.Comment: 14 pages, 19 figure

    Biocompatible Capsules and Methods of Making

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    Embodiments of the invention include capsules for containing medical implants and delivery systems for release of active biological substances into a host body. Delivery systems comprise a capsule comprising an interior enclosed by walls, and a source of active biological substances enclosed within the capsule interior, wherein the active biological substances are free to diffuse across the capsule walls. The capsule walls comprise a continuous mesh of biocompatible fibers and a seal region where two capsule walls overlap. The interior of the capsule is substantially isolated from the medium surrounding the capsule, except for diffusion of at least one species of molecule between the capsule interior and the ambient medium, and prevents cell migration into or out of the capsule. Methods for preparing and using the capsules and delivery systems are provided

    Age-related changes in short-interval intracortical facilitation and dexterity

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    Functional changes in the primary motor cortex might contribute to the age-related decline infine motor control. We measured short-interval intracortical facilitation (SICF) in an intrinsichand muscle with paired-pulse transcranial magnetic stimulation at interstimulus intervals(ISIs) of 1.5, 2.5, and 4.5 ms in young and old subjects and examined its association withdexterity. We found age-related effects in SICF, with greater facilitation in old than youngsubjects at the 1.5-ms ISI and greater facilitation in young than old subjects at the 2.5-ms ISI.SICF at the 2.5-ms ISI was positively correlated with performance on a task that requiredcoordinated and dextrous use of both hands, suggesting that this measure indicates a capacityfor executing demanding manual tasks
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