Non-irradiated Samples Research Articles

Detection and molecular insights into the azurin gene expression post- gamma irradiation in P. aeruginosa.

Azurin, a secondary metabolite from Pseudomonas aeruginosa, has attracted much attention owing to its valuable therapeutic and biological applications. This work aimed to study and chartly maximize the azurin production process using different doses of gamma irradiation (5-400Gy) in P. aeruginosa isolates. Seventy-six P. aeruginosa isolates were sourced from 135 environmental samples and 35 clinical bacterial isolates with the following descending order: 35 isolates (46%) from clinical samples, 26 isolates (34%) from water samples, and 15 isolates (20%) from soil samples. The disc diffusion technique was used for antimicrobial susceptibility testing, revealing that the multidrug-resistant (MDR) rate among all collected isolates according to the criteria determined by Clinical and Laboratory Standards Institute (CLSI) was 54 (71%). The genomic experimental results revealed that only 37 MDR isolates tested positive for the azurin gene, as detected by the PCR product at 446bp. These findings were further supported by FTIR analysis, which revealed peaks around 1636.96cm- 1, indicating a prominent α-helix secondary structure of azurin in these isolates. Related to their pathogenicity and antibiotic resistance, isolates from clinical origin exhibited the higher azurin gene expression level. Besides, this study confirmed the potency of gamma radiation exposure at 50 and 100Gy significantly increased the azurin expression levels in three tested clinical isolates (P ≤ 0.05), with a maximum fold expression level of 63.55 compared to the non-irradiated samples. In conclusion, low doses of gamma irradiation effectively enhanced expression level of a secondary metabolite azurin, providing a considerable benefit for subsequent purification processes in both biological and medical applications.

Effects of gamma and electron-beam irradiations on the stability of free radicals, bioactive compounds and microbial characteristics of turmeric powder

Turmeric is a functional ingredient commonly used in food, pharmaceutical, and cosmetic products due to its health benefits and bioactivity, including anti-inflammatory, antioxidant, and anticancer benefits. Irradiation is a common technique used to decontaminate microorganisms and extend the shelf life of spices. However, there are scientific debates over the use of irradiation in food products. This study aimed to assess the effects of ionizing radiation, including gamma rays and electron beams, on bioactive compounds and microbial characteristics of turmeric powder. Technically, high-performance liquid chromatography with UV–Vis detection was used to assess bioactive compounds. Another aim of the present study was to determine free radicals in irradiated and non-irradiated samples within one month of storage using electron paramagnetic resonance (EPR). Results showed that gamma and electron-beam irradiations could decrease microbial contamination of turmeric by approximately 5 and 6 log cfu/g, respectively. Contents of bioactive compounds increased in irradiated samples and curcumin contents in gamma and electron-beam irradiated samples were 232–248 and 215–266 mg/g dry weight (dw), respectively. Furthermore, the study detected that free radicals increased in all irradiated samples immediately after irradiation but decreased over time. Decrease in EPR signals was faster in gamma-irradiated samples during storage. Numbers of free radicals induced by gamma and electron-beam irradiations were 6.59–4.70, 2.69–1.60, 1.61–1.34, and 0.99–1.05 on days 0, 7, 14, and 21, respectively. After 21 days of storage, the numbers of free radicals in all non-irradiated and irradiated samples were similar. Therefore, free radicals induced by irradiations were degraded during storage and eliminated after 21 days.

Electron-beam irradiation of ZSM-5 catalyst with a designed sample holder: Simulation and experiment

A sample holder has been designed to achieve the uniform absorbed-dose distribution in electron-beam (EB) irradiated ZSM-5 catalyst. Simulated results, without considering the holder’s rotation, demonstrated that the holder configuration should be a cylinder hollow, while its dimensions are recommended to be 10–14 cm in outer radius, 7–8 mm in thickness, and 50–54mm in height. The holder’s rotational contribution to the simulated results was estimated to be less than 1%. An actual holder was fabricated based on this design. Steamed ZSM-5 catalyst (∼32 g) was used to verify the catalytic cracking performance of the sample under EB irradiation. The irradiating experiment was conducted using the fabricated holder, with the 10 MeV EB and a fluence of 8×1014 e.cm−2 (257 kJ). The catalytic cracking experiments indicated that most catalytic productions strongly increased with low heavy cycle oil (HCO) yield when irradiated ZSM-5 was used instead of steamed non-irradiated sample. Excellent increases were simultaneously found, for the first time, for propylene (∼24%) and gasoline (∼15%) productions. Irradiated sample also exhibited superior stability compared to non-irradiated one.

Influence of gamma-irradiation on the physical properties of epoxy/polyaniline composites and application as gamma dosimeter

Abstract The epoxy/pani samples doped with a specified weight ratio of polyaniline pani ware prepare by casting method. Using different doses of gamma rays (0, 2, and 4 kGy) were used to irradiated the prepared samples. Irradiated and non-irradiated samples were imaged using a FE-scanning electron microscope and were found to have regular morphology, and irradiation had obvious effect on this morphology at 4 kGy. When studying the crystal structure of the samples, it was found the samples have a polycrystalline structure, and this structure tends to improve after irradiation, this was verified using X-ray diffraction. Likewise, D.C electrical conductivity increased with increasing gamma radiation doses. Also study the effect of irradiation with gamma rays on optical properties and demonstrate the clear effect of these rays on optical properties. It was also found that the optical energy gap with (indirect allowed transition) was decreases after the irradiation process. Together, these results indicate the possibility of using these samples in the manufacture of gamma dosimeters.

Sodium-Poor, Hydroxyl-Rich, Defective Na2Ti3O7 Prepared by γ-Irradiation and Its Enhanced Proton Conductivity.

The use of γ-irradiation to tailor the physicochemical properties of materials is not widely applied to layered alkali metal oxides. Herein, we show that γ-irradiation (up to 400 kGy) of Na2Ti3O7 leads to a sodium-poor, hydroxyl-rich analogue where the layered structure, plate-like morphology, and textural properties are preserved. The deintercalation of sodium ions modifies the Ti-O bond lengths and expands the unit cell; the latter is supported by density functional theory (DFT) calculations. 23Na solid-state NMR suggests the transport of the symmetric, 7-fold Na2 sites to an intermediate environment, which is closer to the asymmetric, 9-fold Na1 sites. An 8 wt % mass loss (1.4 mol water/mol titanate) is observed, indicating an increased concentration of protons/hydroxyls. These hydroxyl groups (i.e., lattice protons) possess higher thermal stability than solely surface-adsorbed ones in the nonirradiated sample. At 200-400 kGy, the proton conduction (50 °C and ∼70% RH) of ∼10-6 S·cm-1 is 1 order of magnitude larger than that in the nonirradiated sample; the relaxation time decreases from 30 to 2-6 μs with γ-irradiation. The γ-dose dependence of dielectric loss is also present and analyzed using the Jonscher universal power law, indicating the low-frequency dispersion behavior characteristics of high charge densities.

Influence on quality indicators and shelf life of radiation treated poultry meat

Radiation treatment has emerged as a promising technology in food processing, especially for enhancing safety and extending shelf life of poultry meat. The purpose of the study was to ensure the safety and extend the shelf life of poultry exposed to gamma radiation. Radiation doses of 2 kGy, 4 kGy, 6 kGy, 8 kGy were used during irradiation, sensory evaluation and physico-chemical analyzes were carried out, comparative characteristics of irradiated and non-irradiated poultry meat samples were presented. The results showed that the shelf life of poultry meat irradiated at a temperature of 0+2℃ was extended up to 14 days. The article analyzes the effect of gamma rays on fat and moisture, it is shown that the moisture content of poultry meat decreases with an increase in the dose of radiation, at a dose of 8 kg it decreased by 12% in 14 days. It was shown that moisture content of poultry meat samples increased on day 5, after which destruction occurred. It was also shown that the fatty acid content of irradiated poultry meat samples at doses of 6 kGy and 8 kGy decreases with the extension of the storage period. Among all the tested radiation doses, 2kGy, 4kGy showed to be more effective compared to non-irradiated poultry meat with better performance in physico-chemical analysis, be it sensory evaluation. Understanding the effects of radiation on poultry is critical to ensuring consumer safety and maintaining product quality throughout the supply chain.

Irradiating the Path to High-Efficiency Zn-Ion Batteries: An Electrochemical Analysis of Laser-Modified Anodes.

Global energy consumption is increasing yearly, yet the world is trying to move toward carbon neutrality to mitigate global warming. More research is being done on energy storage devices to advance these efforts. One well-known and widely studied technology is Zn-ion batteries (ZIBs). Therefore, this paper demonstrates how laser irradiation at wavelengths of 266 and 1064nm, in the presence of air or water, can enhance the electrochemical performance of metallic zinc anode in alkaline electrolyte. The obtained samples are characterized using X-ray diffraction analysis, scanning electron microscopy, and Raman spectroscopy. Then, the electrochemical properties are studied by cyclic voltammetry and impedance measurements. Results indicate that the laser processing of the Zn sample increases surface-specific capacity by up to 30% compared to the non-irradiated Zn sample. Furthermore, electrochemical measurements reveal enhanced participation of metallic Zn grains in the oxidation and reduction processes in irradiated samples. In future research, integrating laser treatment into electrode preparation processes can become essential for optimizing anode battery materials.

Effects of Gamma Irradiation on Changes in Chemical Composition and Antioxidant Activity of Euphorbia maculata Callus.

In this study, we investigated the effects of gamma irradiation on the antioxidant activity and metabolite profiles of Euphorbia maculata calli (PC3012). Gamma irradiation at various doses (0, 0.05, 0.5, and 10 kGy) significantly enhanced the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS+) radical scavenging activities of the callus extracts of PC3012 in a dose-dependent manner. High-performance liquid chromatography (HPLC) and ultra-performance liquid chromatography-quadrupole time-of-flight/mass spectrometry (UPLC-Q-TOF/MS) analyses revealed that irradiation increased the lysophospholipid content, although no new antioxidant compounds were formed. Furthermore, a PLS-DA analysis revealed evident metabolic differences between non-irradiated and irradiated samples, which were further verified by statistical validation. These findings suggest that gamma irradiation induces specific biochemical modifications that enhance the bioactive properties of PC3012 calli. This technology exhibits potential for utilization in the natural product and food sectors, particularly in the development of functional foods and nutraceuticals with improved health benefits.

The effect of Ar+ and N+ ion irradiation on the thermally induced evolution of the structural and magnetic properties of Co/Pt and Pt/Co bilayered stacks

The application of Co–Pt thin films as functional elements of novel nanoelectronics and spintronics devices requires the formation of a homogeneous ferromagnetic CoPt phase with tunable magnetic properties. A diffusion-controlled synthesis of this ferromagnetic phase can be implemented through the annealing of deposited Co/Pt bilayers. Apart from thermal treatment, both structural and magnetic properties of such layered stacks can be affected by ion preirradiation. In this work, we, therefore, studied the effect of a two-stage process consisting of preirradiation with 110 keV Ar+/N+ ions followed by post-annealing in vacuum at 550°С for 30 min on the evolution of the structural, chemical, and magnetic properties of Co/Pt/substrate and Pt/Co/substrate heterostructures. The results obtained for such two-stage processing were compared to those received after single-stage vacuum annealing. It was found that when ion preirradiation is followed by annealing, the diffusion-driven intermixing of Pt and Co leading to the formation of the ferromagnetic Co–Pt phase is slowed down compared to the non-irradiated samples, which is associated with the barrier effect of implanted projectiles. Furthermore, we demonstrate that preirradiation does not compromise the magnetic properties of the samples. For instance, preirradiation leads to a coercivity increase of up to 38 % compared to the non-irradiated annealed samples which is attributed to the presence of remaining paramagnetic Pt between the grains of the ferromagnetic A1-CoPt phase. We demonstrate that the applied two-stage processing (consisting of ion preirradiation followed by thermal annealing) of magnetic thin films is a promising approach for tailoring their magnetic properties such as the in-plane coercivity, saturation, and effective magnetization.

Reversible Optical Switching of Polyoxovanadates and Their Communication via Photoexcited States.

The 2-bit Lindqvist-type polyoxometalate (POM) [V6O13((OCH2)3CCH2N3)2]2- with a diamagnetic {V6O19} core and azide termini shows six fully oxidized VV centers in solution as well as the solid state, according to 51V NMR spectroscopy. Under UV irradiation, it exhibits reversible switching between its ground S0 state and the energetically higher lying states in acetonitrile and water solutions. TD-DFT calculations demonstrate that this process is mainly initialized by excitation from the S0 to S9 state. Pulse radiolysis transient absorption spectroscopy experiments with a solvated electron point out photochemically induced charge disproportionation of VV into VIV and electron communication between the POM molecules via their excited states. The existence of this unique POM-to-POM electron communication is also indicated by X-ray photoelectron spectroscopy (XPS) studies on gold-metalized silicon wafers (Au//SiO2//Si) under ambient conditions. The amount of reduced vanadium centers in the "confined" environment increases substantially after beam irradiation with soft X-rays compared to non-irradiated samples. The excited state of one POM anion seems to give rise to subsequent electron transfer from another POM anion. However, this reaction is prohibited as soon as the relaxed T1 state of the POM is reached.

Assessment of NB-UVB Effects on Skin of Atopic Dermatitis Patients: A Network Analysis.

Introduction: Atopic dermatitis is a common inflammatory skin disease which is treated with narrowband ultraviolet B (NB-UVB). Exploring the critical targeted genes in patients by UV radiation is the main aim of this study. Methods: Gene expression profiles of lesional and non-lesional skin samples of atopic dermatitis patients after treatment with NB-UVB and the non-irradiated samples were extracted from the Gene Expression Omnibus (GEO) database and analyzed via protein-protein interaction (PPI) network analysis to find the critical targeted genes. Results: A total of 357 significant differentially expressed genes (DEGs) were included in the PPI network. CTNNB1, SRSF1, YWHAB, SMC3, GNB2, ARF3, UBL7, RAB2A, YWHAE, EIF5B, SNRPE, PPIG, RC3H2, CFL1, SMARCB1. LAPTM5, PRPF40A, and RBBP4 were introduced as hub-bottlenecks. Conclusion: In conclusion, five central genes including SMC3, ARF3, EIF5B, SMARCB1, and LAPTM5 were highlighted as the critical genes in response to NB-UVB radiation in the skin of the treated atopic dermatitis patients. The introduced crucial genes are involved in essential cellular functions such as apoptosis, cell cycle, cell proliferation, and inflammation. It seems that applied NB-UVB radiation is a suitable therapeutic method for atopic dermatitis disease.

Volatile Flavor Compounds of Gamma Irradiated Melon (Cucumis melo L.) Seeds by Simultaneous Distillation Extraction and Gas Chromatography-Mass Spectrometry (GC-MS) Analysis

Gamma irradiation is one of the preservation techniques used to increase the shelf life of foods. The current study was aimed to determine the volatile flavor contents of melon (Cucumis melo L.) seeds and the impact of gamma radiation upon these compounds. The seeds were irradiated with gamma rays at 1, 5, 10, and 20 kGy doses. The volatile compounds were extracted by simultaneous distillation extraction (SDE), using n-pentane/diethyl ether (1:1, v/v) and determined by gas chromatography-mass spectrometry (GC-MS). A total of 70 volatile flavor compounds were identified in the control, with 2,3-butanediole (18.01%) and 1-hexanol (6.06%) as the major compounds. The number and percentage of the volatile compounds varied with the gamma irradiation doses. Twenty-eight volatile compounds were present in the non-irradiated and irradiated samples at different concentrations. Up to the recommended gamma irradiation dose of 10 kGy, the number of volatile flavor compounds generally increased. There were changes in both the number and percentages of the identified volatile flavor compounds following gamma irradiation of the Cucumis melo L seeds.

Functional improvement and characterization of protein hydrolysates prepared by the fermentation of irradiated tilapia skin

Gamma irradiation (γ-irradiation) sterilizes and modifies proteins. This study aimed to enhance the performance of protein hydrolysates of fermented tilapia fish skin using irradiation. The results showed that γ-irradiation could effectively kill harmful microorganisms in fish skin at 6 kGy. Irradiation at 1–6 kGy dose disintegrated the internal structure of fish skin proteins, thus increasing the degree of hydrolysis after fermentation by Bacillus subtilis L4; however, irradiation at 9–12 kGy caused cross-linking and aggregation of fish skin proteins. The solubility, and water and oil holding capacity of the protein hydrolysates were significantly improved compared to those of the non-irradiated sample. The maximum emulsifying activity (164.61±16.28 m2/g), foaming activity (91.13±2.30 mL), and surface hydrophobicity index (5766.43±770.56) were observed in the protein hydrolysates fermented from fish skin irradiated at 12 kGy. The antioxidant activity of the protein hydrolysates increased with increasing irradiation doses. This suggested that the functional properties and antioxidant activity of protein hydrolysates from fish skin fermentation can be improved by appropriate irradiation pretreatment, providing a feasible method for improving the utilization and quality of proteins in fishery waste.

Calibration curve for radiation dose estimation using FDXR gene expression biodosimetry – premises and pitfalls

Purpose Radiation-induced alterations in gene expression show great promise for dose reconstruction and for severity prediction of acute health effects. Among several genes explored as potential biomarkers, FDXR is widely used due to high upregulation in white blood cells following radiation exposure. Nonetheless, the absence of a standardized protocols for gene expression-based biodosimetry is a notable gap that warrants attention to enhance the accuracy, reproducibility and reliability. The objective of this study was to evaluate the sensitivity of transcriptional biodosimetry to differences in protocols used by different laboratories and establish guidelines for the calculation of calibration curve using FDXR expression data. Material and Methods Two sets of irradiated blood samples generated during RENEB exercise were used. The first included samples irradiated with known doses including: 0, 0.25, 0.5, 1, 2, 3 and 4 Gy. The second set consisted of three ‘blind’ samples irradiated with 1.8 Gy, 0.4 Gy and a sham-irradiated sample. After irradiation, samples were incubated at 37 °C over 24 h and sent to participating laboratories, where RNA isolation and FDXR expression analysis by qPCR were performed using sets of primers/probes and reference genes specific for each laboratory. Calibration curves based on FDXR expression data were generated using non-linear and linear regression and used for dose estimation of ‘blind’ samples. Results Dose estimates for sham-irradiated sample (0.020–0.024 Gy) and sample irradiated with 0.4 Gy (0.369–0.381 Gy) showed remarkable consistency across all laboratories, closely approximating the true doses regardless variation in primers/probes and reference genes used. For sample irradiated with 1.8 Gy the dose estimates were less precise (1.198–2.011 Gy) but remained within an acceptable margin for triage within the context of high dose range. Conclusion Methodological differences in reference genes and primers/probes used for FDXR expression measurement do not have a significant impact on the dose estimates generated, provided that all reference genes performed as expected and the primers/probes target a similar set of transcript variants. The preferred method for constructing a calibration curve based on FDXR expression data involves employing linear regression to establish a function that describes the relationship between the logarithm of absorbed dose and FDXR ΔCt values. However, one should be careful with using non-irradiated sample data as these cannot be accurately represented on a logarithmic scale. A standard curve generated using this approach can give reliable dose estimations in a dose range from 50 mGy to 4 Gy at least.

Single-cell transcriptional analysis of irradiated skin reveals changes in fibroblast subpopulations and variability in caveolin expression

BackgroundRadiation-induced fibrosis (RIF) is an important late complication of radiation therapy, and the resulting damaging effects of RIF can significantly impact reconstructive outcomes. There is currently a paucity of effective treatment options available, likely due to the continuing knowledge gap surrounding the cellular mechanisms involved. In this study, detailed analyses of irradiated and non-irradiated human skin samples were performed incorporating histological and single-cell transcriptional analysis to identify novel features guiding development of skin fibrosis following radiation injury.MethodsPaired irradiated and contralateral non-irradiated skin samples were obtained from six female patients undergoing post-oncologic breast reconstruction. Skin samples underwent histological evaluation, immunohistochemistry, and biomechanical testing. Single-cell RNA sequencing was performed using the 10X single cell platform. Cells were separated into clusters using Seurat in R. The SingleR classifier was applied to ascribe cell type identities to each cluster. Differentially expressed genes characteristic to each cluster were then determined using non-parametric testing.ResultsComparing irradiated and non-irradiated skin, epidermal atrophy, dermal thickening, and evidence of thick, disorganized collagen deposition within the extracellular matrix of irradiated skin were readily appreciated on histology. These histologic features were associated with stiffness that was higher in irradiated skin. Single-cell RNA sequencing revealed six predominant cell types. Focusing on fibroblasts/stromal lineage cells, five distinct transcriptional clusters (Clusters 0–4) were identified. Interestingly, while all clusters were noted to express Cav1, Cluster 2 was the only one to also express Cav2. Immunohistochemistry demonstrated increased expression of Cav2 in irradiated skin, whereas Cav1 was more readily identified in non-irradiated skin, suggesting Cav1 and Cav2 may act antagonistically to modulate fibrotic cellular responses.ConclusionIn response to radiation therapy, specific changes to fibroblast subpopulations and enhanced Cav2 expression may contribute to fibrosis. Altogether, this study introduces a novel pathway of caveolin involvement which may contribute to fibrotic development following radiation injury.

Effect of Gamma Irradiation on the Antimicrobial and Free Radical Scavenging Activities of Solvents-Based Extracts of Cucurbitaceae Seeds

The effect of gamma irradiation upon the bioactive potentials of selected Cucurbitaceae seeds commonly known as Char Magaz was investigated. The seeds were irradiated in triplicate at doses of 1, 5, 10, and 20 kGy gamma rays in a cobalt-60 irradiator. These were extracted with n-hexane, chloroform, ethyl acetate and methanol and the extracts were concentrated by rotary evaporation. The antimicrobial effects of the irradiated and non-irradiated samples against bacterial strains and the fungal strains were assessed by the agar-well diffusion method and the minimal inhibitory concentration technique. The antioxidant activities were determined via 2, 2-diphenyl-1-picryl-hydrazyl (DPPH), 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS), and ferric reducing antioxidant power (FRAP) methods. The chloroform extract of cucumber seeds exhibited the greatest zone of inhibition (18.0 mm) against S. aureus. Minimal inhibitory concentrations (MIC) for antibacterial and antifungal activities ranged from 320.0 to 1280 µg/mL, and 0.50 to 16.0 µg/mL, respectively. Seeds exposed up to 10 kGy gamma irradiation increased DPPH and ABTS scavenging activities. Comparatively, all seed extracts showed high antioxidant potentials in the FRAP assay at all doses. The results suggested that gamma irradiation up to 10 kGy enhances bioactivities of the analyzed seeds.

STUDY OF SPECTRAL CHARACTERISTICS OF BOVINE SERUM ALBUMIN UNDER THE EFFECT OF MILLIMETER RANGE ELECTROMAGNETIC WAVES

The study of the effect of millimeter range electromagnetic waves (MM EMW) on bovine serum albumin (BSA) structure at the frequencies both resonant (51.8 GHz) and non-resonant (41.8 GHz) for water has been conducted. The absorption and fluorescence spectra of non-irradiated and irradiated samples of physiological solution and BSA with exposition 60 min were obtained. It was revealed that the spectral characteristics of physiological solution did not change under the effect of MM EMW, while the analogous characteristics of BSA change relevantly. It was also shown that the absorption spectra of the irradiated samples significantly differ from those of non-irradiated protein.

Radiation resistance and durability against thermal regeneration cycles of Ag-ETS-10 and Ag-ZSM-5 for collecting radioxenon

Efficient porous adsorbents are crucial for: the mitigation of radioxenon emissions from nuclear installations, the production of Xe and the detection of clandestine nuclear weapon tests. Silver-exchanged zeolites or alike, specifically Ag-ZSM-5 and Ag-ETS-10, are promising candidates for these applications. However, knowledge on their radiation resistance is lacking and further research is necessary on their durability against thermal regeneration cycles. The radiation resistance was investigated for the first time by in situ irradiation with 133Xe up to about 100 MGy on Ag-ETS-10 and Ag-ZSM-5. In parallel, the durability of non-irradiated samples against at least 43 thermal regeneration cycles was investigated on both adsorbents. Fresh, irradiated and thermally regenerated samples were analyzed using different characterization techniques. The characterizations, and more specifically Xe adsorption at 296 K, did not show particular alterations due to the irradiation and thermal regeneration cycles. This is a major step forward for more efficient radioxenon trapping as it proves that both adsorbents can be used up to these irradiation levels and withstand 43 thermal regeneration cycles without any significant loss of Xe adsorption performance. Noteworthily, peak shifting and broadening were observed in the 29Si NMR signals of irradiated Ag-ETS-10 due to the paramagnetic 133Cs decay product.

LBDNet interlaboratory comparison for the dicentric chromosome assay by digitized image analysis applying weighted robust statistical methods

Purpose This interlaboratory comparison was conducted to evaluate the performance of the Latin-American Biodosimetry Network (LBDNet) in analyzing digitized images for scoring dicentric chromosomes from in vitro irradiated blood samples. The exercise also assessed the use of weighted robust algorithms to compensate the uneven expertise among the participating laboratories. Methods Three sets of coded images obtained through the dicentric chromosome assay from blood samples irradiated at 1.5 Gy (sample A) and 4 Gy (sample B), as well as a non-irradiated whole blood sample (sample C), were shared among LBDNet laboratories. The images were captured using the Metafer4 platform coupled with the AutoCapt module. The laboratories were requested to perform triage scoring, conventional scoring, and dose estimation. The dose estimation was carried out using either their laboratory calibration curve or a common calibration curve. A comparative statistical analysis was conducted using a weighted robust Hampel algorithm and z score to compensate for uneven expertise in dicentric analysis and dose assessment among all laboratories. Results Out of twelve laboratories, one had unsatisfactory estimated doses at 0 Gy, and two had unsatisfactory estimated doses at 1.5 Gy when using their own calibration curve and triage scoring mode. However, all doses were satisfactory at 4 Gy. Six laboratories had estimated doses within 95% uncertainty limits at 0 Gy, seven at 1.5 Gy, and four at 4 Gy. While the mean dose for sample C was significantly biased using robust algorithms, applying weights to compensate for the laboratory’s analysis expertise reduced the bias by half. The bias from delivered doses was only notable for sample C. Using the common calibration curve for dose estimation reduced the standard deviation (s*) estimated by robust methods for all three samples. Conclusions The results underscore the significance of performing interlaboratory comparison exercises that involve digitized and electronically transmitted images, even when analyzing non-irradiated samples. In situations where the participating laboratories possess different levels of proficiency, it may prove essential to employ weighted robust algorithms to achieve precise outcomes.

Experimental study on activating bismuth active centers in bismuth/erbium co-doped optical fiber by ionizing radiations

Post-treatments by ionizing radiations have been proposed previously for regulating the properties of bismuth/erbium co-doped optical fiber (BEDF). In this work, the effects of common ionizing radiations (i.e. gamma ray, electron beam and mixed γ/neutron) on Bismuth Active Centers (BACs) in BEDF have systematically been investigated. Our experimental results show obvious BAC activation by ionizing radiation – evident from the increase in saturable absorption at 830 nm that is closely associated with the BAC responsible for the desirable near infrared (NIR) emissions. This radiation induced BAC activation has been confirmed from the emission of BAC associate with silica (BAC-Si). The saturation pump power of the BAC-Si emission in all irradiated samples is found higher than that in pristine (or non-irradiated) samples. In addition, the effect on emission by different radiation is found in the order of gamma ray > mixed gamma/neutron > electron beam. On the other side, we have also observed significant radiation induced unsaturable loss that can affect the pumping efficiency and Figure of Merit (FOM).