Abstract Pataky, K., Villanueva, G., Liani, A., Zgheib, O., Jenkins, N., Halazonetis, D. J., Halazonetis, T. D. and Brugger, J. Microcollimator for Micrometer-Wide Stripe Irradiation of Cells Using 20-30 keV X Rays. Radiat. Res. 172, 252-259 (2009). The exposure of subnuclear compartments of cells to ionizing radiation is currently not trivial. We describe here a collimator for micrometer-wide stripe irradiation designed to work with conventional high-voltage X-ray tubes and cells cultured on standard glass cover slips. The microcollimator was fabricated by high-precision silicon micromachining and consists of X-ray absorbing chips with grooves of highly controlled depths, between 0.5-10 microm, along their surfaces. These grooves form X-ray collimating slits when the chips are stacked against each other. The use of this device for radiation biology was examined by irradiating human cells with X rays having energies between 20-30 keV. After irradiation, p53 binding protein 1 (53BP1), a nuclear protein that is recruited at sites of DNA double-strand breaks, clustered in lines corresponding to the irradiated stripes.
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http://dx.doi.org/10.1667/RR1483.1 | DOI Listing |
Nanotechnology
January 2016
Physics of Interfaces and Nanomaterials, MESA+ Institute for Nanotechnology, University of Twente, PO Box 217, NL-7500AE Enschede, The Netherlands.
Controlling the alignment and orientation of nanorods on various surfaces poses major challenges. In this work, we investigate hydrodynamic confinement and capillary alignment of gold nanorod assembly on chemically stripe-patterned substrates. The surface patterns consist of alternating hydrophilic and hydrophobic micrometer wide stripes; a macroscopic wettability gradient enables controlling the dynamics of deposited suspension droplets.
View Article and Find Full Text PDFRadiat Res
August 2009
Microsystems Laboratory, Ecole Polytechnique Federale de Lausanne (EPFL), Lausanne, Switzerland.
Abstract Pataky, K., Villanueva, G., Liani, A.
View Article and Find Full Text PDFScience
July 2006
Materials Sciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720, USA.
A remarkable dependence of the friction force on carrier concentration was found on doped silicon substrates. The sample was a nearly intrinsic n-type Si(100) wafer patterned with 2-micrometer-wide stripes of highly B-doped p-type material. The counter surface was the tip of an atomic force microscope coated with conductive titanium nitride.
View Article and Find Full Text PDFPhys Rev Lett
September 2003
Service de physique de l'état condensé, DRECAM/DSM CEA Saclay, Orme des merisiers, 91191 Gif sur Yvette, France.
Magnetic excitations of micrometer-wide ferromagnetic stripes subjected to a transverse applied field have been measured between 1 and 20 GHz. The complexity of the observed response is attributed to the spatially nonuniform equilibrium spin distribution. This one is modeled analytically and numerically, which allows one to distinguish two micromagnetic phases governing the ground state.
View Article and Find Full Text PDFAnal Chem
March 1998
Department of Chemistry, University of California, Riverside 92521, USA.
A laser-generated interference pattern was used to remove enzyme from micrometer-wide stripes on an enzyme-covered carbon fiber microelectrode surface to create regions of facile electron transfer. Fluorescence microscopy was used to visualize fluorophore-tagged enzyme to indicate where the adsorbed enzyme remained on the surface. The electrochemical kinetics of the carbon fiber surface were examined to see if electron-transfer sites could indeed be segregated from enzyme adsorbed across the entire surface.
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