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Design of Bioresponsive Polymers
Published in Deepa H. Patel, Bioresponsive Polymers, 2020
Anita Patel, Jayvadan K. Patel, Deepa H. Patel
In the sample, the x-rays interrelate with the electrons and so the technique is susceptible toward electron density dissimilarities [75]. There are both laboratory instruments anchored in added conventional basis and synchrotron-based instrumentations for these x-ray measurements. The neutrons are interacting with the nuclei in the sample in the small-angle neutron scattering (SANS) technique, and the interaction relies on the real isotope [76]. Hydrogen, as well as deuterium, has incredibly dissimilar scattering lengths and this can be developed on the contrary difference measurements wherein it is common that fraction of the particle in solution is deuterated. Through mixing deuterated and protonated solvents one can alter the scattering length density of the solvent. The system has requirement of a neutron source that is a nuclear reactor otherwise an accelerator base spallation source and for that reason, the experimentations are carried out at large scale services.
Secondary Radiation Production and Shielding at Proton Therapy Facilities
Published in Harald Paganetti, Proton Therapy Physics, 2018
The characteristics of the prompt radiation field in the immediate vicinity of the radiation source are strongly dependent upon the proton energy. At large distances from the radiation source, the prompt radiation field consists of two components: direct and scattered [4]. Secondary radiation may escape the roof and then be scattered down by the atmosphere or be scattered by the roof to the ground level; if the roof shielding is thin compared to the lateral walls, secondary radiation may escape the roof and then be scattered down by the atmosphere; or be scattered by the roof to the ground level. This process is loosely referred to as “skyshine.” Similarly, “groundshine” refers to the radiation that escapes the floor slab, reaches the earth, and scatters upwards or radiation scattered upwards from the floor slab. Roof and floor slabs shielding should be thick enough to prevent both skyshine and groundshine. Neutron scattering is more important than photon scattering because neutrons are not easily absorbed above thermal energies. The neutron component is much higher than the photon component at proton therapy facilities. For skyshine, it is also important to consider the presence of adjacent elevated floors and multistoried buildings. In general, skyshine and groundshine are not of concern at facilities that have well-shielded roofs and floor slabs.
Radiation protection in the nuclear industry
Published in Alan Martin, Sam Harbison, Karen Beach, Peter Cole, An Introduction to Radiation Protection, 2018
Alan Martin, Sam Harbison, Karen Beach, Peter Cole
Neutron capture in the structural materials of the reactor and in the shield results in the emission of capture γ rays and makes these materials radioactive. The radiation from the decay of the radioactivity, as in the case of fission products, continues to be emitted when the reactor is shut down. Neutron scattering also leads to γ ray emission but does not, in general, induce radioactivity.
Factors affecting the preparation of nanocrystals: characterization, surface modifications and toxicity aspects
Published in Expert Opinion on Drug Delivery, 2023
Shirleen Miriam Marques, Lalit Kumar
Small-angle neutron scattering (SANS) is a method that can be employed to determine structural characteristics at the nanoscale and to investigate modifications taking place in a substance due to various handling and processing techniques as well as changes occurring in-situ [163,164]. Any alterations in the surface structure of crystals could be investigated through fractal dimension parameters and/or the specific surface area. Moreover, for crystalline substances, the data acquired through SANS could be utilized to correlate alterations taking place on the atomic scale, as probed through diffraction, with structural modifications on the nanoscale [163]. Costabile and coworkers performed SANS on nanocrystals conjugated with PEG to deliver a filamenting temperature-sensitive mutant Z protein inhibitor to the lungs. The damaging effects of interaction with mucin were perceptible at a larger scale, i.e. on the nanocrystal size. Concerning the release pattern, the SANS results suggested that the nanocrystals underwent partial dissolution when incubated with mucin [165].
Self-emulsifying drug delivery systems: a novel approach to deliver drugs
Published in Drug Delivery, 2022
For the investigation of microemulsion, scattering approaches have been used. Small-angle X-ray scattering (SAXS), DLS, PCS, and small angle neutron scattering (SANS) are some of the techniques used. Structural data provided by SAXS on macromolecules vary in size from 5 to 25 nm, as well as repetition distances in partly ordered systems up to 150 nm in partially ordered systems. It is used to determine the structure of particle systems at nanoscale or at microscale, including size of particles, dispersion, morphologies, and the surface-to-volume ratio, among other things. To use SANA is to find droplet shape and size. Micelles, oil-swollen micelles, and mixed micelles, are described by the term 'droplet'. The interference effect of wavelets dispersed from diverse materials in a sample is used in small-angle neutron scattering investigations.
Investigation of neutron and gamma radiation protective characteristics of synthesized quinoline derivatives
Published in International Journal of Radiation Biology, 2020
Bünyamin Aygün, Burak Alaylar, Kadir Turhan, Erdem Şakar, Mehmet Karadayı, Mohammed Ibrahim Abu Al-Sayyed, Emel Pelit, Medine Güllüce, Abdulhalik Karabulut, Zuhal Turgut, Bünyamin Alım
To reduce neutron scattering in the measurements of neutron absorption, in Figure 1, the path between the neutron source, the sample and the detector was kept very short. Thus, the neutron absorption values were determined from the dose measurements of the samples. Experimental investigation rates were also theoretically calculated with the FLUKA code. The obtained results of the present measurements are presented in Table 5. Thus, absorbed dose rate (experiment) was created with the calculation using the formula [(DM 100)/D0], here DM; absorbed dose by sample, D0; dose background. Absorbed dose rate (theory) was created by calculations made with FLUKA program.