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Basic Atomic and Nuclear Physics
Published in Michael Ljungberg, Handbook of Nuclear Medicine and Molecular Imaging for Physicists, 2022
Gudrun Alm Carlsson, Michael Ljungberg
The atomic nucleus comprises two elementary particles, protons and neutrons, which have approximately the same mass; however, the proton carries a positive charge, and its magnitude is equal to that of the electron’s negative charge. The neutron is electrically neutral. A common name for both the protons and the neutrons is the ‘nucleon’. The main characteristics of the electron, proton, and neutron are summarized in Table 2.1.
Low Energy Particle Accelerators and Laboratories
Published in Vlado Valković, Low Energy Particle Accelerator-Based Technologies and Their Applications, 2022
A large number of experiments has been done on low energy accelerators, in particular Van de Graaff accelerators and tandems. There are many textbooks, books, reports and scientific papers written on the subject of low energy nuclear physics and its applications using electrostatic accelerators as a tool. The study of atomic nuclei is central to our understanding of the world around us. Comprising 99.9% of the visible matter in the universe nuclei are, in multiple aspects, central to fundamental questions in physics, such as our understanding of the origin of the elements and how complex many-body quantum systems organize. Their properties depend sensitively on the number of protons (Z) and neutrons (N), and much of what we know about them comes from the measurement and characterization of their excitation modes and energy levels. Understanding nuclear properties, their role within the cosmos, and more broadly their application for society, requires measurements on elements and isotopes at the limits of their mass (N + Z), charge (Z), and β-decay stability (N–Z). In short, low energy nuclear physics research concerns itself with understanding the structure and stability of the nuclei in the atoms that make up the world around us, as well as the reactions which formed them in the cosmos.
Radioactivity
Published in W. P. M. Mayles, A. E. Nahum, J.-C. Rosenwald, Handbook of Radiotherapy Physics, 2021
Discovered by Henri Becquerel in 1896 in the form of emissions from uranium, radioactivity is commonly described as the possibility that a given atomic nucleus will spontaneously emit particles through disintegration, leading to possible change in its physical and chemical properties. In 1898, Pierre and Marie Curie announced that they had identified two hitherto unknown elements: polonium and radium. These elements were much more radioactive than uranium and formed a very small fraction of the uranium ore pitchblende.
Synthesis, DFT calculations, and anti-proliferative evaluation of pyrimidine and selenadiazolopyrimidine derivatives as dual Topoisomerase II and HSP90 inhibitors
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2023
Samar El-Kalyoubi, Samiha A. El-Sebaey, A. M. Rashad, Hanan A. AL-Ghulikah, Mostafa M. Ghorab, Sherin M. Elfeky
The molecular electrostatic potential (MEP) refers to electron density in the molecule that is important for understanding electrophilic and nucleophilic reaction sites as well as hydrogen bonding interactions in the system37. MEP was calculated using B3LYP/6–31G* method, and the obtained results show and predict the reactive sites of the electrophilic or nucleophilic molecule. The electrostatic potential surface appears in different colours, red, blue, and green, corresponding to the most negative, positive, and zero electrostatic potential regions, respectively. The negative electrostatic potential represents proton attraction by the molecule’s aggregate electron density (red colour), whereas the positive electrostatic potential corresponds to proton repulsion by the atomic nuclei (blue colour). Figure 10 depicts the total electron density surface mapped with the molecular electrostatic potential MEP plot (solid and mesh views) for the calculated compound 3a.
Therapeutic Nuclear Magnetic Resonance affects the core clock mechanism and associated Hypoxia-inducible factor-1
Published in Chronobiology International, 2021
Viktoria Thöni, Regina Oliva, David Mauracher, Margit Egg
Nuclear Magnetic Resonance (NMR) forms the basis for Magnetic Resonance Imaging (MRI), Magnetic Resonance Spectroscopy (MRS), as well as for the therapeutic tool of NMR therapy (tNMR or MBST®-NMR). tNMR is used for the treatment of osteoarthritis and osteoporosis and regeneration of bone and soft tissue. Its basis, and that of the other above listed techniques, is the so-called spin effect, as a quantum mechanical property of atomic nuclei with an odd number of protons or neutrons . When such spinning nuclei, for example, hydrogen protons, are exposed to an external magnetic field, they align in parallel or antiparallel to the field lines. The application of an additional corresponding radio frequency pulse forces the nuclear spins to deviate from the spin direction, thereby gaining energy. Once the radio frequency pulse ceases, the increase in energy is released to the close environment of the nuclei. In MRI, this release of energy is used for the generation of images, while in MRS it is used to determine the concentrations of chemical compounds. In tNMR, the release of energy is supposed to affect a yet unspecified cellular signaling, which consequently leads to regeneration and healing of the irradiated tissue. While MRI and MRS require strong magnetic fields, typically in the range of several Tesla, the MBST® therapy device generates a magnetic field of only 0.4 mT, and the used radio frequencies, therefore, are much lower as well (MBST®-NMR: 17 kHz-130 kHz compared to MRI: 10 MHz–200 MHz).
Decontamination of rat and human skin experimentally contaminated with 99mTc, 201Tl and 131I radionuclides using “Dermadecon” – a skin decontamination kit: an efficacy study
Published in Cutaneous and Ocular Toxicology, 2018
Dhruv Kumar Nishad, Supriya Bhalla, Kushagra Khanna, Braj Gaurav Sharma, Harish Singh Rawat, Gaurav Mittal, Aseem Bhatnagar
Radioactivity can be defined as emission of electromagnetic radiation and nuclear particles by transformation of atomic nuclei and spontaneous decay. Radioactive contamination usually spreads when radioactive material is released in the environment and leads to exposure of living beings and non-living area. Human radiation exposure as a result of reactor accidents or any other nuclear accident is generally characterized in three ways: whole or partial body exposure as a result of close proximity to a radiation source, external and internal contamination1. All three kinds can affect a given person during a radiation accident. Total or partial body exposure occurs when an external source irradiates either cursorily to the skin or deeply into the internal tissues depending on the type and energy of the radiation involved2.