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Ionisation Chambers
Published in W. P. M. Mayles, A. E. Nahum, J.-C. Rosenwald, Handbook of Radiotherapy Physics, 2021
The electronics required to measure the charge (or current) is provided by the electrometer, which in most cases, includes a voltage supply and a display unit. Most modern electrometers also have the ability to interface with a computer for both parameter selection and data acquisition. For further details on electrometers, readers are referred to Andreo et al. (2017). In the early days of radiation dosimetry, physicists used a gold-leaf electroscope equipped with a quantitative scale as an electrometer. Today, most electrometers are based on negative-feedback operational amplifiers.
Dictionary
Published in Mario P. Iturralde, Dictionary and Handbook of Nuclear Medicine and Clinical Imaging, 1990
Electroscope. Instrument for detecting the presence of electric charges by the deflection of charged bodies. If an insulated conductor with an attached light-flexible member (e.g., a gold leaf) is charged, then this member will move away from the conductor under the mutual coulomb repulsion of the shared charge and will reach equilibrium under electrostatic and gravitational forces. The charge is reduced if the air near the leaf is ionized and the leaf then moves toward the conductor. The rate at which the leaf moves is proportional to the rate of production of ions.
Nanoparticle carrier co-delivery of complementary antibiofilm drugs abrogates dual species cariogenic biofilm formation in vitro
Published in Journal of Oral Microbiology, 2022
Guilherme Roncari Rocha, Kenneth R. Sims, Baixue Xiao, Marlise I. Klein, Danielle S.W. Benoit
The structure of biofilms treated with the prevention protocol was evaluated at 19 h, representing nascent biofilm, and 43 h, representing mature biofilm, via confocal microscopy (Figure 9) and at 43 h using scanning electroscope microscopy (Figure 10). Biofilms treated with unloaded NPC or PBS (diluent of NPC) exhibited greater and more rapid accumulation of microbes on the HA surface. At 19 h, the biofilm had many cells, and a rich exopolysaccharide matrix that protected these microorganisms, and this community continued growing into mature biofilm [5]. NPC and PBS-treated mature biofilm was similar structurally but with even more robust EPS. NPC-far-myr and NPC-myr-1771 treatments delayed maturation of biofilms, which had fewer microcolonies at 19 h compared to PBS and unloaded NPC. After 43 h, NPC-far-myr and NPC-myr-1771 treated biofilms exhibited similar complexity to PBS controls. Thus, NPC-far-myr and NPC-myr-1771 treatments delayed biofilm formation but did not ultimately hinder colony formation at the latter time point. In contrast, there were only a few isolated microorganisms and no EPS accumulated for NPC-far-1771 and NPC-far-myr-1771 formulations at either time point. Therefore, these two formulations did not just delay but also impeded biofilm development. The amount of biofilm and the difference in biomass were even visible without magnification (Supporting Information Figure S3).