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Other Cyclotron Radionuclides
Published in Frank Helus, Lelio G. Colombetti, Radionuclides Production, 2019
Some accelerator-made nuclides are also useful as radiation sources. As the positron source, 22Na and 68Ge-68Ga are used. 57Co is the most popular source in Mössbauer spectroscopy. Mössbauer spectroscopy with this source gives information about the chemical state of iron in various substances including biological samples.53 When a nuclide emits two γ-rays successively, the angular correlation between them sometimes offers information about the microscopical environment of this nuclide.18111In emits γ-rays of 0.117 MeV and 0.247 MeV, and is a useful source for the angular correlation study.
Single-Molecule Kinetics
Published in Clive R. Bagshaw, Biomolecular Kinetics, 2017
Force provides a general method to perturb equilibria between macromolecular states and, hence, also to perturb the kinetics (Section 3.7). Biomolecular motors evolved to transduce chemical energy into work (= force × distance) and investigating the way force feeds back on the chemical states helps to elucidate their mechanisms (Section 5.4). Chemical-to-mechanical energy transduction can be studied in only a few systems at the macroscopic level, muscle contraction being one notable example. However, at the level of single molecules, the mechanics of practically any molecule can be studied. Applying a force to a macromolecule may yield information about how it folds, the conformational states it can explore, and the kinetics of the transitions between states.
Who Are the Drug Users?
Published in Bernard Segal, Perspectives on Drug Use in the United States, 2014
Franklin C. Shontz, James V. Spotts
The only way the task of studying drug abusers can be approached systematically is by pretending that human beings are to some degree simpler or less human than they obviously are. The pretense is made manifest by creating an artificial definition of persons and then proceeding to study actual people as if that definition were correct. For example, if people are defined as emitters of respondent behavior, then they are studied with behaviorist theories and techniques. If they are defined as chemical states and processes, they are studied differently than they would be if they are defined as psychosocial entities or as mind-body interactions.
Review of industrially recognized polymers and manufacturing processes for amorphous solid dispersion based formulations
Published in Pharmaceutical Development and Technology, 2023
Sumit Kumar Saha, Amita Joshi, Romi Singh, Kiran Dubey
Acceptable long-term stability (typically, 24 months) is always required for the commercialization of the drug product. Formulations shall be tested under accelerated conditions (40 ± 2 °C/75 ± 5% RH) and long-term stability conditions (25 ± 2 °C/60 ± 5% RH) as per International Conference for Harmonisation (ICH) guidelines in various packaging configurations for specified times. The formulated ASD shall maintain the physical and chemical state throughout the stability condition to ensure formulation stability. From a regulatory perspective, the pharmaceutical industries shall establish that ASD-based formulation meets all quality specifications (e.g. dissolution, chemical degradation, etc.) in addition to maintenance of the amorphous state (i.e. no evidence of crystallization) of the drug to ensure in vivo performance through the shelf-life of the drug product (Pandi et al. 2020).
Manganese-containing polydopamine nanoparticles as theranostic agents for magnetic resonance imaging and photothermal/chemodynamic combined ferroptosis therapy treating gastric cancer
Published in Drug Delivery, 2022
Zhian Chen, Zhenhao Li, Chuangji Li, Huilin Huang, Yingxin Ren, Zhenyuan Li, Yanfeng Hu, Weihong Guo
The morphology and elements mapping of NPs were characterized by transmission electron microscopy (TEM) (JEOL JEM-2100F TEM, Tokyo, Japan). The chemical state and composition were characterized by X-ray photoelectron spectroscopy (XPS) (ESCALAB250Xi, Thermo Fisher, Waltham, MA). Electron spin resonance (ESR, JEOL, Ltd., Tokyo, Japan) was used to measure the production of •OH. The Mn content in the PP@Mn NPs was determined by inductively coupled plasma mass spectrometry (ICP-MS) (Optima7300DV, PerkinElmer, Waltham, MA). A Shimadzu UV-2600 UV-vis spectrophotometer (Kyoto, Japan) was used to acquire ultraviolet (UV)–vis absorption spectra. The hydrodynamic diameter and zeta potentials were measured using a Zetasizer Nano ZS (Malvern, Worcestershire, UK) by dynamic light scattering (DLS). The powder X-ray diffraction (XRD) patterns were acquired on a PANalytical X’Pert PRO X-ray diffractometer. The photothermal capability was assessed used an 808 nm semiconductor lasers (Shanghai Xilong Optoelectronics Technology Co., Ltd., Shanghai, China). Relaxivity of different PP@Mn NPs concentrations (0, 125, 250, 500, and 1000 μg/mL) was placed in tube holders for measurements by a 3.0-T Philips Achieva clinical MRI scanner (Philips Healthcare, Best, The Netherlands). The signal-to-noise ratio (SNR) was defined as: SNR = SImean/SDnoise. Infrared (IR) thermal images were acquired using an IR thermal camera (FLIR E50, Wilsonville, OR).
Inotersen therapy of transthyretin amyloid cardiomyopathy
Published in Amyloid, 2020
Noel R. Dasgupta, Stacy M. Rissing, Jessica Smith, Jeesun Jung, Merrill D. Benson
Close monitoring of cardiac parameters has shown efficacy of inhibition of TTR production as measured by both structural and functional status of disease. As of one year of the study the 15 subjects analysed mainly showed lack of progression of disease [7]. Now data from subjects at both 2 and 3 years of treatment indicate not only lack of disease progression, but in some subjects, a decrease in cardiac amyloid burden (Figure 3). This finding suggests that ATTR cardiac amyloid deposits may represent a chemical state where decreasing the substrate for fibril formation may reverse an equilibrium and result in reabsorption of the deposited amyloid. This has been documented for immunoglobulin light chain (AL) amyloidosis when the offending plasma cell dyscrasia is effectively treated and AA (secondary, reactive) amyloidosis when plasma serum amyloid A levels have normalised. The present study suggests that a similar effect can be attained by restricting the ATTR fibril precursor protein. Amyloid, while defined by the main protein constituent, is really a complex substance with varying proportions of a number of biologic entities including glycosaminoglycans and serum amyloid P (SAP). Disruption of this state by restricting availability of the main protein constituent may lead to dissolution.