A new instrumental neutron activation analysis (INAA) for the simultaneous determination of titanium (TiO) and silica (SiO) dioxide as UV-filters in sunscreens is described. Samples are encapsulated, neutron irradiated (30 s) and after a suitable decay (3 min), the induced Ti (T = 5.76 min) and Al (T = 6.56 min) radionuclides are measured for the emitted γ-ray fingerprint. Three applications were carried out: (i) screening study (analysis of commercial sunscreens in combination with single particle inductively coupled plasma mass spectrometry (sp-ICP-MS); (ii) research study (development of innovative UV-filters such as titanium dioxide or bismuth titanate loaded inorganic mesoporous silica nanoparticles, MSN); (iii) validation study (intercalibration of a spectrochemical method - inductively coupled plasma optical emission spectrometry, ICP-OES). Collectively, the nuclear method appears a powerful tool adequate for quantifying TiO and SiO in the above studies. The limited accessibility at the nuclear reactor for neutron activation is probably one of the reasons why the excellent characteristics of the nuclear technique are not always fully known and exploited in the industrial and research chemical world.
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http://dx.doi.org/10.1016/j.aca.2022.339601 | DOI Listing |
Sci Rep
January 2025
Los Alamos National Laboratory, Los Alamos, NM, 87544, USA.
Detecting shielded special nuclear material, such as nuclear explosives, is a difficult challenge pursued by non-proliferation, anti-terrorism, and nuclear security programs worldwide. Interrogation with intense fast-neutron pulses is a promising method to characterize concealed nuclear material rapidly but is limited by suitable source availability and proven instrumentation. In this study we have pioneered a demonstration of such an interrogation method using a high-intensity, short-pulse, laser-driven neutron source that offers potential benefits compared to conventional neutron sources.
View Article and Find Full Text PDFStructure
January 2025
Department of Computational Chemistry, Lund University, Chemical Centre, P.O. Box 124, 221 00 Lund, Sweden; European Spallation Source ESS ERIC, P.O. Box 176, 221 00 Lund, Sweden. Electronic address:
Lysozyme is a model system for crystallographers. In this issue of Structure, Ramos et al. report atomic resolution neutron structures of lysozyme, which unambiguously show the protonation states and hydrogen-bonding networks of the active site.
View Article and Find Full Text PDFSmall
December 2024
Institute of Chemistry, University of Potsdam, Karl-Liebknecht-Straße 24-25, 14476, Potsdam, Germany.
Antimicrobial resistance (AMR) is a major cause of death worldwide. This urges the search for alternatives to antibiotics, and antimicrobial polymers hold promise due to their reduced susceptibility to AMR. The topology of such macromolecules has a strong impact on their activity, with bottlebrush architectures outperforming their linear counterparts significantly.
View Article and Find Full Text PDFJ Colloid Interface Sci
December 2024
Institute for Frontier Materials, Deakin University, Geelong VIC 3216, Australia. Electronic address:
Hypothesis: Optimizing interfacial positioning of crosslinkers within a reactive self-assembled hexagonal lyotropic liquid crystals (HLLC) system could assist in retaining the hexagonal structure during polymerization and thereby improving water filtration performances of the as-synthesized nanofiltration membranes.
Experiments: The positioning of the hydrophilic crosslinker, poly (ethylene glycol) diacrylate (PEGDA), within the reactive HLLC system was systematically investigated using H and C solid nuclear magnetic resonance (NMR) and small angle X-ray scattering (SAXS) techniques. The structural variation and water filtration performances of these HLLC systems with/without crosslinkers after polymerization were further studied using grazing incidence SAXS (GISAXS) and crossflow filtration tests, respectively.
J Colloid Interface Sci
December 2024
School of Health Sciences, Stopford Building, The University of Manchester, Oxford Road, Manchester M13 9PT, UK.
Hypothesis: Nanoscale characterisation of the self-associated species formed by amphiphilic pharmaceuticals in aqueous solution carries relevance across their entire journey from development through to manufacture - relevant, therefore, not only as regards formulation of the drug products as medicines, but also potentially relevant to their bioavailability, activity, and clinical side effects. Such knowledge and understanding, however, can only be fully secured by applying a range of experimental and theoretical methodologies.
Experiments: Herein, we apply a synergistic combination of solubility, surface tension, SANS, NMR and UV spectroscopic studies, together with MD simulation and QM calculations, to investigate the meso-structures of propranolol hydrochloride aggregates in bulk aqueous solutions, at concentrations spanning 2.
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