Browsing by Subject "Irradiation"

Now showing 1 - 3 of 3
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    Copper-Linked Rotaxanes for the Building of Photoresponsive Metal Organic Frameworks with Controlled Cargo Delivery
    (American Chemical Society, 2020-07-09) Saura Sanmartín, Adrián; Martinez-Cuezva, Alberto; Bautista, Delia; Marzari, Mara R. B.; Martins, Marcos A. P.; Alajarín, Mateo; Berná, José; Berná, José; Química Orgánica
    We have prepared a photoresponsive metal–organic framework by using an amide-based [2]rotaxane as linker and copper(II) ions as metal nodes. The interlocked linker was obtained by the hydrogen bond-directed approach employing a fumaramide thread as template of the macrocyclic component, this latter incorporating two carboxyl groups. Single crystal X-ray diffraction analysis of the metal–organic framework, prepared under solvothermal conditions, showed the formation of stacked 2D rhombohedral grids forming channels decorated with the interlocked alkenyl threads. A series of metal–organic frameworks differing in the E/Z olefin ratio were prepared either by the previous isomerization of the linker or by postirradiation of the reticulated materials. By dynamic solid state 2H NMR measurements, using deuterium-labeled materials, we proved that the geometry of the olefinic axis of the interlocked struts determined the obtention of materials with different independent local dynamics as a result of the strength of the intercomponent noncovalent interactions. Moreover, the usefulness of these novel copper-rotaxane materials as molecular dosing containers has also been assayed by the diffusion and photorelease of p-benzoquinone, evaluated in different solvents and temperatures.
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    Effects of irradiation on intestinal cells in vivo and in vitro
    (Murcia : F. Hernández, 2002) Wróblewski, R.; Wróblewski, J.; Jalnäs, M.; Van Decker, G.; Björk, J.; Roomans, G.M.
    The effects of irradiation on intestinal epithelial cells were analyzed in vivo and in vitro. The in vivo study was carried out on the rat small intestine and for the in vitro study the intestinal crypt cell-line IEC-6 was used. Rat intestine and IEC-6 cells were irradiated with X-ray doses ranging between 1-16 Gy. Energ y - dispersive X-ray microanalysis was used for detection of the elemental changes in the cells. Cell morphology was investigated in the scanning electron microscope, DNAsynthesis by autoradiography of 3H - t h y m i d i n e incorporating nuclei and proliferation by cell counting. Our results indicate that in vivo, in the crypt cells, the increasing doses of irradiation led to increased sodium and lowered potassium and phosphorus concentrations. Corresponding ion shifts were found in the irradiated IEC-6 cells. Cells continued to proliferate up to the dose of 8 Gy, although the proliferation rate became lower with increasing dose of irradiation. The increasing dose of irradiation significantly reduced DNA-synthesis (16 Gy decreased DNA-synthesis by 50%) which resulted in a complete inhibition of cell proliferation. Analysis of goblet cells also showed characteristic radiationdependent elemental changes. Scanning electron microscopical investigation of cells in culture revealed that most of the control cells were flat and had rather smooth cell membranes. Irradiation led to the appearance of numerous different membrane manifestations (microvilli of varying length and distribution, and blebs). Frequency of differences in the topology of the cells was related to the dose of irradiation. Our study clearly demonstrates that even low doses of irradiation cause changes in the ionic composition of the cells and inhibit DNA-synthesis and cell proliferation. The effects observed in the crypt cells in vivo were the same as in the intestinal cell line i n v i t ro, which indicates that IEC-6 cells can be used for investigation of side effects of radiation to the abdomen.
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    Más allá de los datos: la transformación digital del museo tradicional
    (Universidad de Murcia. Servicio de Publicaciones, 2023) Sans Pinillos, Alger; Costa, Vicent
    Este trabajo se centra en el museo virtual entendido como la transformación digital del museo tradicional. En primer lugar, se revisan las principales conceptualizaciones del museo virtual en la literatura especializada y, a partir de las mis-mas, se propone una definición básica. Asimismo, se presentan argumentos que muestran la ciencia de la perspectiva dataísta en el estudio de la injusticia epistémica relativa al museo virtual. Finalmente, se analiza la exclusión relativa a la participación y la interacción entre las visitantes de un museo (tanto virtual como físico) y la propia institución.