Hydrogen detection near surfaces and shallow interfaces with resonant nuclear reaction analysis

This review aims to present an overview of the application of stable isotope technology in clinical pharmacology. Three main categories of stable isotope technology can be distinguished in clinical pharmacology. Firstly, it is applied in the assessment of drug pharmacology to determine the pharmacokinetic profile or mode of action of a drug substance. Secondly, stable isotopes may be used for the assessment of drug products or drug delivery systems by determination of parameters such as the bioavailability or the release profile. Thirdly, patients may be assessed in relation to patient-specific drug treatment; this concept is often called personalized medicine. In this article, the application of stable isotope technology in the aforementioned three areas is reviewed, with emphasis on developments over the past 25 years. The applications are illustrated with examples from clinical studies in humans.

https://bpspubs.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-2125.2011.04071.x

Applications of stable isotopes in clinical pharmacology

SiC is unique amongst the wide bandgap semiconductors in that the natural thermal oxide is stoichiometric SiO2, as is the case for silicon The possibility of producing devices such as MOSFET in which thermal SiO2 is used as the gate insulator has motivated substantial work aimed at understanding the morphology and electrical properties of the SiO2/ SiC interface and the processes responsible for thermal oxide growth The oxide growth kinetics are quite different, parallel and anti- parallel to the crystal polar direction We review the experimental study of the nature of the thermal oxide grown in ultra- dry oxygen and of the extended interfacial region at the SiO2/ SiC interface on the nominally Si- terminated and C- terminated polar surfaces of hexagonal polytypes of SiC, highlighting how the use of stable isotopic tracing has helped to clarify processes for which kinetics measurements alone do not prove to be sufficiently incisive

https://iopscience.iop.org/article/10.1088/0022-3727/40/20/S10/pdf

Growth of SiO2 on SiC by dry thermal oxidation: mechanisms

Nuclear resonant reaction analysis techniques for hydrogen depth profiling in solid materials typically have used15N ion beams at 6.40 MeV and19F ion beams at 6.42 MeV, which require a tandem accelerator. We report a new technique using an18O ion beam at a resonance energy of 2.70 MeV, which requires only a single stage accelerator. Improved values of the nuclear parameters for the 2.70 MeV (18O) and 6.40 MeV (15N) resonances are reported. The beam energy spread was investigated for different ions and ion charge states and found to scale with the charge state. Data obtained using atomic and molecular gas targets reveal the research potential of Doppler spectroscopy. Examples of hydrogen depth profiling in solid materials using15N and18O ion beams are presented.

Hydrogen depth profiling using 18 O ions

Nanoparticles, which range in size from 1 to 100 nm in at least one dimension, exhibit unique physicochemical properties that are dependent upon their size, shape, dispersion, surface functionalization or de-functionalization, and binding with biomembranes and proteins. Because the size effects are exponential, a minor change in a nanoparticle's structure may cause major alterations in their properties. Bulk materials (>500 nm), on the other hand, have constant physical properties regardless of their size or shape. It is well established that the biological activity of nanoparticles depends upon their physicochemical properties and size. Therefore, an accurate determination of a nanoparticle's size and properties is a prerequisite for controlling its biological properties and/or stability. This chapter elucidates some of the methods commonly used for nanoparticle characterization.

Chapter 4 – Experimental Methodologies for the Characterization of Nanoparticles

High resolution depth profiling in near-surface regions of solids by narrow nuclear reaction resonances below 0.5 MeV with low energy spread proton beams

A method of analysis for oxygen 18 is described, based on the anodic oxidation of specially prepared tantalum wires implanted through cannulas into the tissue of living animals. The thin anodic oxide layer formed on these wires is then analyzed by the 18O(p,alpha)15N reaction. The isotopic oxygen concentration of water in the brain obtained by this method compares very well with the values obtained by conventional analysis using mass spectrometry. This in vivo method of nuclear microanalysis has been used in both metabolic and equilibration experiments involving oxygen 18. The half-life for the turnover of 18O in body water was found to be about 3 days. A simple three-pool model is presented which can account for the experimental results obtained from the dilution by body water of interperitoneally injected water highly enriched in 18O.

In vivo measurement of variations in the oxygen 18 content of water in rat brain.

Compounds enriched in the rare isotopes of light elements, such as 18 O, 17 O, 13 C or 15 N, are used in a very large variety of isotopic tracing studies including investigating the microscopic mechanisms of the movements of atoms in solids. Owing to their very high cost or limited availability these products must be handled in gram amounts or less. Handling such compounds in small quantities in the liquid or gaseous state, purifying and recovering them for further use require special techniques that are described in detail in this paper. Dedicated vacuum lines are used for labelled water, special high vacuum furnace installations are required for thermal treatments with labelled gases that must be used under static conditions while remaining pure. Ion beam analysis is systematically used to investigate the wide spectrum of applications of isotopic tracing in electrochemistry and in applied physics. A number of typical experiments are outlined briefly providing examples for future experimental development in this field.

Handling, purification and recovery of isotopically enriched water or gases for isotopic tracing experiments with ion beam analysis in electrochemistry and physics

G Amsel

Papers

High resolution depth profiling in near-surface regions of solids by narrow nuclear reaction resonances below 0.5 MeV with low energy spread proton beams

In vivo measurement of variations in the oxygen 18 content of water in rat brain.

Handling, purification and recovery of isotopically enriched water or gases for isotopic tracing experiments with ion beam analysis in electrochemistry and physics