Searches for Exotic Interactions Using Neutrons

Slow neutrons possess several advantageous properties which make them useful probes for a variety of exotic interactions, including some that can form at least some components of the dark matter of interest for this issue of Symmetry. We discuss the relevant neutron properties, describe some of the recent work that has been done along these lines using neutron experiments mainly with cold and ultra-cold neutrons, and outline some interesting and exciting opportunities which can be pursued using resonant epithermal neutron interactions in heavy nuclei.

Synthesis, Molecular Docking, and In Vitro Boron Neutron Capture Therapy Assay of Carboranyl Sinomenine

In comparison with pristine sinomenine and carborane precursors, the calculations of molecular docking with matrix metalloproteinases (MMPs) and methylcarboranyl-n-butyl sinomenine showed improved interactions. Accordingly, methylcarboranyl-n-butyl sinomenine shows a high potential in the treatment of rheumatoid arthritis (RA) in the presence of slow neutrons. The reaction of potassium salt of sinomenie, which is generated from the deprotonation of sinomenine (1) using potassium carbonate in a solvent of N,N-dimethyl formamide, with 4-methylcarboranyl-n-butyl iodide, (2) forms methylcarboranyl-n-butyl sinomenine (3) in 54.3% yield as a new product. This new compound was characterized by 1H, 13C, and 11B NMR spectroscopy, FT-IR spectroscopy, and elemental analyses to confirm its molecular composition. In addition to molecular docking interactions with MMPs, the in vitro killing effects of 3, along with its toxicity measurements, exhibited its potential to be the new drug delivery agent for boron neutron capture synovectomy (BNCS) and boron neutron capture therapy (BNCT) for the treatment of rheumatoid arthritis (RA) and cancers in the presence of slow neutrons, respectively.

Aza-BODIPY: A New Vector for Enhanced Theranostic Boron Neutron Capture Therapy Applications

Boron neutron capture therapy (BNCT) is a radiotherapeutic modality based on the nuclear capture of slow neutrons by stable 10B atoms followed by charged particle emission that inducing extensive damage on a very localized level (<10 μm). To be efficient, a sufficient amount of 10B should accumulate in the tumor area while being almost cleared from the normal surroundings. A water-soluble aza-boron-dipyrromethene dyes (BODIPY) fluorophore was reported to strongly accumulate in the tumor area with high and BNCT compatible Tumor/Healthy Tissue ratios. The clinically used 10B-BSH (sodium borocaptate) was coupled to the water-soluble aza-BODIPY platform for enhanced 10B-BSH tumor vectorization. We demonstrated a strong uptake of the compound in tumor cells and determined its biodistribution in mice-bearing tumors. A model of chorioallantoic membrane-bearing glioblastoma xenograft was developed to evidence the BNCT potential of such compound, by subjecting it to slow neutrons. We demonstrated the tumor accumulation of the compound in real-time using optical imaging and ex vivo using elemental imaging based on laser-induced breakdown spectroscopy. The tumor growth was significantly reduced as compared to BNCT with 10B-BSH. Altogether, the fluorescent aza-BODIPY/10B-BSH compound is able to vectorize and image the 10B-BSH in the tumor area, increasing its theranostic potential for efficient approach of BNCT.

MODIFIED BORON-TITANIUM AUSTENITIC STAINLESS-STEEL ALLOYS FOR POWER REACTORS

Boron, Titanium and boron – titaniumaustenitic stainless steel alloys were developed to be used as a nuclear reactor shielding material. Three grades of steel alloys with base composition of AISI316 but having either Ti or B or Ti and B (SS316Ti, SS316B and SS316TiB) were designed and produced using 30 kg pilot plant medium frequency induction furnace at the same conditions. Samples of the properly treated steels were subjected to microstructure observation, hardness, tensile and impact testing. The microstructure observation revealed an austenitic phase in all investigated steel alloys. Among the investigated steels, the lowest corrosion rate was found in the modified steel containing B. The macroscopic-cross sections for neutrons > 10 keV, slow, and total slow neutrons were carried out using 241Am-Be neutron source. The developed boron and boron-titanium stainless steel alloys were found to have higher cross sections for neutrons > 10 keV, slow, and total slow neutrons than SS316 while the modified Ti- stainless steel has lower values for slow neutrons and neutrons > 10 keV than the standard stainless steel SS316. Moreover, the associated neutron half value layer (HVL) was calculated for each sample. Additionally, gamma ray shielding properties were performed for several gamma ray energies that emitted from 232Th radioactive source.

Light- and Neutron-Optical Properties of Holographic Transmission Gratings from Polymer-Ionic Liquid Composites with Submicron Grating Spacing

We investigate the applicability of polymer-ionic liquid composites as optical elements for light, as well as for slow neutrons. The gratings are recorded using two-beam mixing and are characterized experimentally based on their diffraction properties. We produced a set of samples differing in their thickness, ranging from 10 m – 100 m . We demonstrate that it is possible to prepare transmission gratings with a lattice constant of Λ = 480 n m , resulting in thick gratings for light, as well as neutrons. The presented samples show low optical losses in the Vis-UV spectrum and exhibit refractive index modulations of about 10 - 3 at λ = 543 n m . However, further improvements have to be made to obtain efficient neutron optical components.