Nanostructures via DNA scaffold metallization

金沢大学大学院自然科学研究科物質情報解析金沢大学理学部The critical role of polymers in process of noble metals nanostructures formation is well known, however, the use of DNA chain template in this process is yet largely unknown. In this study we demonstrate different ways of silver deposition on DNA template and report the influence of silver nanostructures formation on DNA conformational state. Metallization of DNA chain proceeds by two different scenarios depending on DNA conformation. If DNA chain is unfolded (elongated) chain, silver reduction leads to the nucleation of silver nanoparticles and their growth on DNA scaffold. Silver nanoparticles assemble on negatively charged DNA template due to electrostatic interactions. During formation of silver nanoparticles, DNA chain, similarly to other polyelectrolytes, plays a role of stabilizing agent, and silver nanoparticles formed in DNA solutions are smaller and have narrower size distributions as compared to the particles formed in DNA-free solutions. Since positive change of thus formed silver nanoparticles is rather low, DNA chain remains in unfolded conformation no matter how high is a concentration of silver nanoparticles. On the other hand, when DNA molecule has been compacted into tight condensate, naturally of a toroid shape, deposition of silver on compacted DNA chain proceeds in a different manner without discretion into nanoparticles. As a result of such silver metal deposition, DNA-templated silver nanorings are formed. By comparison of UV-Vis spectra changes, the detection of transition point between unfolded and compact DNA conformations becomes possible. Metallization of unfolded DNA chain brings nanoparticles of about 30-50 nm size, while deposition of silver metal on a compact DNA condensate gives 100-150 nm metal rings that are distinguished by optical properties. The approach of different scenario of metallization can be used for detection of conformational changes in biopolymers

UNCERTAINTIES OF PERSONAL NEUTRON DOSIMETERS READINGS AT WORKPLACES

Personal neutron dosimeters were calibrated with few reference neutron sources. These dosimeters were placed into operational fields. The comparison of dosimeters readings and “true” value of Hp(10) has shown poor agreement. The effective dose might be overestimate up to 10503%. It was revealed, that Hp(10) has better agreement with the effective dose in the anteroposterior geometry and not applicable for other geometries

DEVELOPMENT OF HARDWARE-SOFTWARE SOLUTION FOR MODELING OF RADIOACTIVE IMPURITIES ATMOSPHERIC SCATTERING

Hardware-software solution for athmospheric scattering of radioactive impurities model-ing were being developed. Other tools for such analisys were reviewed. Demonstration of intermediary software blocks is presented

Physical and nuclear shielding properties of newly synthesized magnesium oxide and zinc oxide nanoparticles

Magnesium oxide (MgO) and Zinc oxide (ZnO) nanoparticles (NPs) have been successfully synthesized by solid–solid reaction method. The structural properties of ZnO and MgO NPs were studied using X-ray diffraction (XRD) and scanning electron microscopy (SEM). XRD results indicated a formation of pure MgO and ZnO NPs. The mean diameter values of the agglomerated particles were around to be 70 and 50 nm for MgO and ZnO NPs, respectively using SEM analysis. Further, a wide-range of nuclear radiation shielding investigation for gamma-ray and fast neutrons have been studied for Magnesium oxide (MgO) and Zinc oxide (ZnO) samples. FLUKA and Microshield codes have been employed for the determination of mass attenuation coefficients (μm) and transmission factors (TF) of Magnesium oxide (MgO) and Zinc oxide (ZnO) samples. The calculated values for mass attenuation coefficients (μm) were utilized to determine other vital shielding properties against gamma-ray radiation. Moreover, the results showed that Zinc oxide (ZnO) nanoparticles with the lowest diameter value as 50 nm had a satisfactory capacity in nuclear radiation shielding. © 2020 Korean Nuclear Societ

Synthesis, physical, optical, mechanical, and radiation attenuation properties of TiO2–Na2O–Bi2O3–B2O3 glasses

A series of bismo-borate (50-x)B2O3-xTiO2-15Na2O–30Bi2O3 glass samples (where x = 0, 2.5, 5, 7.5, and 10 wt%) doped with TiO2 were fabricated via the melt-quenching technique. The gamma and neutron shielding, physical, optical, and mechanical properties of the prepared samples were investigated. The experimental results were measured using an HPGe detector. 152Eu, 133Ba, 137Cs, and 60Co radioactive sources were used with energies in the range of 81–1408 keV. The experimental results were compared with both the FLUKA code and the XCOM database. The addition of TiO2 increased the density of the glass samples and decreased their molar volume. The mass attenuation coefficient (MAC) decreased as photon energy decreased, while it increased as TiO2 concentration increased. The half value layer (HVL) and mean free path (MFP) of the glass samples increased when the photon energy increased and decreased as the TiO2 concentration increased. The absorbance of the present samples is enhanced by using TiO2, meaning they can be used to protect humans from UV light. Both direct and indirect band gaps decreased as TiO2 content increased from 0 to 10 wt %. Moreover, the electronic transition between localized states is valid in the present samples. The radiation shielding, optical, physical, and mechanical properties of the fabricated glass samples demonstrate their utility for diagnostic gamma shielding. © 2020 Elsevier Ltd and Techna Group S.r.l

A Comprehensive Evaluation of the Attenuation Characteristics of Some Sliding Bearing Alloys under 0.015–15 MeV Gamma-Ray Exposure

In this study, three different sliding bearing alloy samples were investigated in terms of their performance on attenuation characteristics and behavioral attitudes under 0.015–15 MeV gamma-ray exposure. Accordingly, different types of advanced calculation methods were utilized to calculate the radiation shielding parameters. Next, several gamma-ray shielding parameters and exposure rates in addition to fast neutron removal cross-section were determined. Furthermore, exposure and energy absorption buildup factors were determined by using G-P fitting method. Mass attenuation coefficients (MAC) values were recorded as 2.5246, 2.5703, and 2.5827 (cm2 /g) for Alloy1, Alloy2, and Alloy3 samples at 15 MeV photon energy, respectively. At 40 mfp, the highest EBF values were reported as 1,376,274, 1,003,593, and 969,373 for Alloy1, Alloy2, and Alloy3 samples. The results of this extended investigation showed that the Alloy3 sample with the highest Pb reinforcement amount has superior shielding capability among the investigated samples. It can be concluded from the results that substitution of Pb with Bi in the recent alloy structure has a monotonic effect on different types of shielding parameters. Therefore, it can also be concluded that Pb is a remarkable tool for the improvement of the shielding properties of studied alloy structures. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.Deanship of Scientific Research, King Faisal University, DSR, KFU: R.G.P.1/1/42Funding: The authors extend their appreciation to the Deanship of Scientific Research at King Khalid University for funding this work through research groups program under grant number R.G.P.1/1/42

Exploring the ftir, optical and nuclear radiation shielding properties of samarium-borate glass: A characterization through experimental and simulation methods

(Tl2O3 )30-(Li2O)10-(B2O3)(60−y)-(Sm2O3 )y glass system with various Sm2O3 additives (y = 0, 0.2, 0.4, 0.6) was studied in detail. The vibrational modes of the (Tl2O3 )30-(Li2O)10-(B2O3 )(60−y) network were active at three composition-related IR spectral peaks that differed from those mixed with Samarium (III) oxide at high wavenumber ranges. These glass samples show that their permeability increased with the Samarium (III) oxide content increase. Additionally, the electronic transition between localized states was observed in the samples. The MAC, HVL, and Zeff values for radiation shielding parameters were calculated in the energy range of 0.015–15 MeV using the FLUKA algorithm. In addition, EBF, EABF, and ΣR values were also determined for the prepared glasses. These values indicated that the parameters for shielding (MAC, HVL, Zeff, EBF, EABF, and ΣR) are dependent upon the Samarium (III) oxide content. Furthermore, the addition of Samarium (III) oxide to the examined glass samples greatly reinforced their shielding capacity against gamma photon. The findings of the current study were compared to analyses of the XCOM software, some concretes, and lead. In the experiment, it was found that the SMG0.6 glass sample was the strongest shield. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.The APC was funded by ?Dunarea de Jos? University of Galati, Romania