An alpha particle has a mass of 4 atomic mass units (amu) and is equal to a helium nucleus (i.e., two protons and two neutrons, and a charge of +2). (cdc.gov)
Atomic Mass Number-- The total number of nucleons (neutron plus protons) in the nucleus of an atom. (cdc.gov)
Atomic Number-- The number of protons in the nucleus of an atom. (cdc.gov)
Atoms are made up of a dense nucleus that contains positively charged protons and neutrally charged neutrons. (snexplores.org)
It is identical to a helium nucleus, i.e., 2 neutrons and two protons, with a mass number of 4 and an electrostatic charge of +2. (docslib.org)
Helium nucleus1
A helium nucleus emitted during the alpha decay of a nucleus. (teachastronomy.com)
Neutrons1
Hint ] Applications that worry about cross-sections for scattering through one angle, or another, include astrophysical studies of gravitational lensing, and a wide range of diffraction and imaging experiments with electrons, neutrons, ions, and light. (umsl.edu)
Atoms2
The elements that make up biological molecules (C, H, N, O, P, S) are too light (low atomic number, Z) to be clearly visualized as individual atoms by transmission electron microscopy. (wikipedia.org)
Alpha Particle (symbolized by Greek letter )-- A charged particle emitted from the nucleus of certain radioactive atoms. (cdc.gov)
Proteins found2
A heterogeneous family of water-soluble structural proteins found in cells of the vertebrate lens. (lookformedical.com)
The team used radiocarbon dating of crystalline proteins found within the nuclei of the eye lens. (scienceblogs.com)
Radioactive1
Alpha Particle-A positively charged particle ejected spontaneously from the nuclei of some radioactive elements. (docslib.org)
Light Sources for Optical Microscopy - The performance of the various illumination sources available for optical microscopy depends on the emission characteristics and geometry of the source, as well as the focal length, magnification and numerical aperture of the collector lens system. (fsu.edu)
Neutron1
Ordinary atomic cross-sections for neutron interaction are typically closer in size to the geometric cross-section of the nucleus (about a barn). (umsl.edu)
Electrons2
The nucleus is orbited by a cloud of negatively charged electrons. (snexplores.org)
The electrons are considered to move in circular or elliptical orbits or, more accurately, in regions of space around the nucleus. (silver-colloids.com)
Microscope1
Feynman believed that if the electron microscope could be made powerful enough, then it would become possible to visualize the atomic structure of any and all chemical compounds, including DNA. (wikipedia.org)
Focal3
Specific heat of a liquid using calorimeter, focal length of a concave mirror and a convex lens using u-v method, Speed of sound using resonance column, Verification of Ohm's law using voltmeter and ammeter, and specific resistance of the material of a wire using meter bridge and post office box. (pdfright.com)
Two thin lenses of focal lengths f 1 and f 2 are in contact and coaxial. (examside.com)
A boy is trying to start a fire by focusing sunlight on a piece of paper using an equiconvex lens of focal length 10 cm. (examside.com)
Geometric1
The effective cross-section per atom is hundreds of times the geometric area of the nucleus. (umsl.edu)
Diffraction3
The marvel of X-ray crystallography is the beauty and precision of the atomic structures deduced from diffraction patterns. (iucr.org)
In favorable circumstances, which are not at all atypical, the number of unique reflections in the diffraction from a crystal exceeds the number of parameters needed to define its atomic structure, often manyfold overdeterminatively. (iucr.org)
However, since the atomic parameters relate nonlinearly to diffraction patterns, structure solution requires having an initial model within the radius of convergence of a minimization procedure that can relate the atomic model to the diffraction data. (iucr.org)
Astronomical1
Atomic astronomical range of variation of these physical quantities, different methods of measurement for different magnitudes of the same physical quantity. (successcds.net)
Silicon1
Pure silicon exists in a shiny, dark-gray crystalline form and as a shapeless powder. (snexplores.org)
Atom3
Atomic Mass-- The mass of a neutral atom of a nuclide, usually expressed in terms of 'atomic mass units. (cdc.gov)
Absorption Coefficient-Fractional absorption of the energy of an unscattered beam of x- or gamma- radiation per unit thickness (linear absorption coefficient), per unit mass (mass absorption coefficient), or per atom (atomic absorption coefficient) of absorber, due to transfer of energy to the absorber. (docslib.org)
Atomic structure-properties of cathode rays and positive rays-specific charge of an electron-atom model Thomson atom model-Rutherford atom model-Bohr atom model-merits and demerits-quantum numbers X-rays-production-properties-Bragg's law-Bragg's X-ray spectro meter photo electric effect-lasers pontaneous and stimulated emission-laser action-characteristics of laser light-ruby laser-applications of laser relativity-Einstein's mass energy relation-variation of mass with velocity. (soaneemrana.org)
Procedure1
A procedure for removal of the crystalline lens in cataract surgery in which an anterior capsulectomy is performed by means of a needle inserted through a small incision at the temporal limbus, allowing the lens contents to fall through the dilated pupil into the anterior chamber where they are broken up by the use of ultrasound and aspirated out of the eye through the incision. (lookformedical.com)
Thin2
The thin noncellular outer covering of the CRYSTALLINE LENS composed mainly of COLLAGEN TYPE IV and GLYCOSAMINOGLYCANS. (lookformedical.com)
Insertion of an artificial lens to replace the natural CRYSTALLINE LENS after CATARACT EXTRACTION or to supplement the natural lens which is left in place. (lookformedical.com)
The making of a continuous circular tear in the anterior capsule during cataract surgery in order to allow expression or phacoemulsification of the nucleus of the lens. (lookformedical.com)
en] Madan M. Rehani, Massachusetts General Hospital and Harvard Medical School, Boston Methods for Eye Lens Dosimetry and Studies On Lens Opacities with Interventionalists Radiation induced cataract is a major threat among staff working in interventional suites. (iaea.org)
Primarily1
Recent studies by the principal investigator's group, primarily among interventional cardiologists, on behalf of the International Atomic Energy Agency, show posterior subcapsular (PSC) changes in the eye lens in 38-53% of main operators and 21-45% of support staff. (iaea.org)
Atomic structure determination is prominent among these, and is arguably pre-eminent. (iucr.org)
Electronic and Atomic Structure of Chalcogenide Phase Change Material Ge2Sb2Te5. (mrs.org)
Alpha1
Alpha-crystallins also act as molecular chaperones that bind to denatured proteins, keep them in solution and thereby maintain the translucency of the lens. (lookformedical.com)
Intriguing phenomena arising at the atomic scale have been found in functional complex oxide materials in recent years due to significant progress in technical and methodological development in scanning transmission electron microscopy (STEM). (mrs.org)
The important radio radiation at 21-cm wavelength from interstellar neutral atomic hydrogen. (teachastronomy.com)
Particles1
A lthough light's wavelength is too large to examine objects much smaller than a biological cell, one method to explore structures on the atomic scale (and smaller) is to toss particles with even smaller wavelengths at those structures, and see what happens if and when they collide. (umsl.edu)
Radiation3
With increasing emphasis on radiation induced cataracts and reduction in threshold dose for eye lens, there is a need to implement strategies for estimating eye lens dose. (iaea.org)
The accumulated radiation dose to the eye lens can be high, leading to concerns about potential radiation injury from these scans. (iaea.org)
The radiation dose to the eye lens from clinical CT brain perfusion studies can be estimated using Monte Carlo simulation methods on voxelized patient models. (iaea.org)
Model1
His model considered only an unscreened repulsive nucleus, but nonetheless worked well for large scattering angles. (umsl.edu)
Presence1
The presence of these proteins accounts for the transparency of the lens. (lookformedical.com)
Energy1
Galaxy whose nucleus emits more energy than other, normal galaxies. (teachastronomy.com)
Scale2
However, the performance of such materials is strongly dependent on the quality of the crystals and the interfaces at the atomic scale. (mrs.org)
Of particular interest is the micro- or nano-structural basis for the rapidly reversible, thermally-induced atomic scale rearrangements that underlie the phase change phenomenon. (mrs.org)
Studies1
TU-E-201-01: Methods for Eye Lens Dosimetry and Studies On Le. (iaea.org)
Small1
The space in the eye, filled with aqueous humor, bounded anteriorly by the cornea and a small portion of the sclera and posteriorly by a small portion of the ciliary body, the iris, and that part of the crystalline lens which presents through the pupil. (lookformedical.com)
Light1
This becomes the basis for how reality in our physical dimension is projected as a hologram from the original coherent light from the eye of the Creator, YHVH (Yod Heh Vod Heh), then passing through the lens of the Galactic Central Sun/Metatron into the Pleiades where the holographic pattern is encoded. (mind-matrix.net)
Vision2
Partial or complete opacity on or in the lens or capsule of one or both eyes, impairing vision or causing blindness. (lookformedical.com)
Lens diseases refer to conditions that affect the lens of the eye, impairing vision and potentially leading to blindness if left untreated. (lookformedical.com)