Epithermal neutron activation,radiometric, correlation and principal component analysis applied to the distribution of major and trace elements in some igneous and metamorphic rocks from Romania

Six major (Na, Al, K, Ca, Ti, Fe) and 28 trace (Sc, Cr, V, Mn, Co, Zn, Cu, As, Br, Sr, Rb, Zr, Mo, Sn, Sb, Ba, Cs, La, Ce, Nd, Eu, Sm, Tb, Hf, Ta, W, Th and U) elements were determined by epithermal neutron activation analysis (ENAA) in nine Meridional Carpathian and Macin Mountains samples of igneous and metamorphic rocks. Correlation and principal factor analysis were used to interpret data while natural radionuclides radiometry shows a good correlation with ENAA results.     

LiSr4(BO3)3:Ce3+ phosphor as a new material for ESR dosimetry

LiSr₄(BO₃)₃:0.01Ce³⁺ phosphor was investigated to assess its potential as a material for measurements of radiotherapeutic doses with electron spin resonance (ESR). The ESR spectrum of the phosphor irradiated with ⁶⁰Co features five ESR signals. An isochronal annealing experiment has shown that the strongest of these signals is associated with the same trap center as the 473 K peak on the TL glow curve of this material. The dose–response is linear in the studied range from 0.89 to 90.30 Gy. Fading of the signal was also investigated.     

In vitro evaluation of the intensifying photodynamic effect due to the presence of plasmonic hollow gold nanoshells loaded with methylene blue on breast and melanoma cancer cells

BackgroundHypoxia is one of the most important limiting factors in photodynamic therapy that can reduce the effectiveness of this treatment. By designing a nanocomplex of plasmonic nanoparticles and photosensitizers with similar optical properties, the rate of free oxygen radical production can be increased and the efficiency of photodynamic therapy can be improved. in this study, we tried to use the outstanding capacities of hollow gold nanoshells (HGNSs) as a plasmonic nanocarrier of methylene blue (MB) to improve the performance of photodynamic therapy.Methods and materialAfter synthesis and optimization of hollow gold nanoshells loaded with Methylene blue (HGNSs-PEG-MB), the characteristics of MB, HGNSs, HGNSs-PEG, HGNSs-PEG-MB, and their toxicity at different concentrations on the cell lines was determined. After determining of optimum concentration of nano agents, irradiation of cell was performed with non-coherent of light source with 670 nm wavelength and an intensity of 14.9 mW/cm². Twenty-four hours after irradiation, an MTT assay was used to determine cell survival percentage. To compare the results, we defined different indexes such as treatment efficiency (TE), synergism ratio (SYN), and the amount of exposure required for 50% cell death (ED50). All the tests were repeated at least four times on the DFW and MCF-7 cancer cell lines.ResultsFor combination therapies with Lumacare irradiated HGNSs-PEG-MB, the UC index was less than one for all concentrations (P < 0.05). Also, the IC50 index for this nanostructure in non-irradiated conditions and less than 9 min irradiation time was lower than other treatment groups (P < 0.05). ED50 amounts for HGNSs-PEG-MB in all concentrations were greater than the other groups. TE Index was also reported to be greater than 1 in all irradiation conditions and concentrations.ConclusionIn this study, HGNSs-PEG in the role of nanocarriers for methylene Blue was used. The results showed that irradiated HGNSs-PEG-MB by 670 nm light severely induced cell death and greatly improved the efficiency of photodynamic therapy in melanoma and breast cancer cells.     

The improved antibacterial efficiency of a zinc phthalocyanine when embedded on silver nanoparticle modified silica nanofibers

This work reports on the fabrication and modification of electrospun polymer free silica nanofibers (SiO₂ NFs) with the aim of creating heterogeneous antibacterial catalysts. The optical and photophysical properties of the obtained NFs i.e. bare SiO₂, Ag-SiO₂, Pc-SiO₂ and Pc@Ag-SiO₂ NFs (Pc = phthalocyanine) were compared and reported. The singlet oxygen quantum yields of the Pc-SiO₂ and Pc@Ag-SiO₂ NFs were also quantified and found to be 0.08 and 0.12, respectively, in water. All the modified SiO₂ NFs were found to possess photoactivity against S. aureus with the most effective being the Pc@Ag-SiO₂ NFs due to the synergy between the Pc and Ag nanoparticles. The bare SiO₂ NFs do not exhibit any antibacterial activity while the Ag-SiO₂ and Pc@Ag-SiO₂ NFs were found to also exhibit dark toxicity. The generated photocatalysts are attractive because they are active against bacteria and they are easily retrievable post-application. The nanocatalysts reported herein are therefore feasible candidates for real-life antibacterial applications.     

Synthesis and Evaluation of [67Ga]-AMD3100: A Novel Imaging Agent for Targeting the Chemokine Receptor CXCR4

In order to develop a possible C-X-C chemokine receptor type 4 (CXCR4) imaging agent for oncological scintigraphy, [⁶⁷Ga]-labeled 1,1′-[1,4-Phenylene-bis(methylene)]bis(1,4,8,11-tetraazacyclotetradecane) ([⁶⁷Ga]-AMD3100) was prepared by using [⁶⁷Ga]GaCl₃ and AMD-3100 for 2 h at 50 °C (radiochemical purity: >95% ITLC, >99% HPLC, specific activity: 1800–2000 TBq/mmol) in acetate buffer. The stability of the complex was checked in the presence of human serum (37 °C) and in the final formulation for four days. The biodistribution of the labeled compound in the vital organs of wild type Sprague-Dawley rats was determined and compared with that of the free Ga³⁺ cation up to 48 h. Considering the spleen as the target organ, the best target:non target ratios were obtained 48 h post-injection (spleen:blood ratio; 14.5 and spleen:muscle ratio; 88.4). Initial SPECT images and biodistribution results in the wild type rats matched each other and demonstrated rapid washout of the tracer from the urinary tract. SPECT images in human breast carcinoma-bearing mice demonstrated a detectable tumor uptake in 48 h post-injection.     

AB-BNCT beam shaping assembly based on 7Li(p,n)7Be reaction optimization

A numerical optimization of a Beam Shaping Assembly (BSA) for Accelerator Based-Boron Neutron Capture Therapy (AB-BNCT) has been performed. The reaction ⁷Li(p,n)⁷Be has been considered using a proton beam on a lithium fluoride target. Proton energy and the dimensions of a simple BSA geometry have been varied to obtain a set of different configurations. The optimal configuration of this set is shown.     

Isotopic noble gas signatures released from medical isotope production facilities—Simulations and measurements

Radioxenon isotopes play a major role in confirming whether or not an underground explosion was nuclear in nature. It is then of key importance to understand the sources of environmental radioxenon to be able to distinguish civil sources from those of a nuclear explosion. Based on several years of measurements, combined with advanced atmospheric transport model results, it was recently shown that the main source of radioxenon observations are strong and regular batch releases from a very limited number of medical isotope production facilities.This paper reviews production processes in different medical isotope facilities during which radioxenon is produced. Radioxenon activity concentrations and isotopic compositions are calculated for six large facilities. The results are compared with calculated signals from nuclear explosions. Further, the outcome is compared and found to be consistent with radioxenon measurements recently performed in and around three of these facilities. Some anomalies in measurements in which ^131mXe was detected were found and a possible explanation is proposed. It was also calculated that the dose rate of the releases is well below regulatory values.Based on these results, it should be possible to better understand, interpret and verify signals measured in the noble gas measurement systems in the International Monitoring of the Comprehensive Nuclear-Test-Ban Treaty.     

Quantitative and analytical comparison of isodose distributions for shaped electron fields from ADAC Pinnacle treatment planning system and Monte Carlo simulations

We assess the accuracy of ADAC Pinnacle³ commercial treatment planning system (TPS) in computation of isodose distributions for shaped electron fields. The assessment is based on comparison of dose profiles generated by TPS and a Monte Carlo model for different beam energies, applicator sizes, and percentages of field blocking. Dose differences of up to 14% are observed at the depth of maximum dose. These discrepancies, often ignored in clinical evaluations, are attributable to inadequate modeling of scatter from applicators and blocks by TPS.