A laser can operate in regular but also in nuclear ionizing radiation environments. This paper presents the results of a real time measuring method used to detect the laser induced damage threshold ...(LIDT) in the optical surfaces/volumes of TEMPAX borosilicate glasses operating in high gamma rays fields. The laser damage quantification technique is applied by using of an automated station intended to measure the damage threshold of optical components, according to the International Standard ISO 21254. Single and multiple pulses laser damage thresholds were determined. For an optical material, life time when it is subjected to multiple pulses of high power laser radiation can be predicted. A few ns pulses shooting laser, operating in regular conditions, inflects damage to a target by its intense electrical component but also in a lower manner by local absorption of its transported thermal energy. When the beam is passing thru optical glass elements affected by ionizing radiation fields, the thermal component is starting to have a more important role, because of the increased thermal absorption in the material's volume caused by the radiation induced color centers. LIDT results on TEMPAX optical glass windows, with the contribution due to the gamma radiation effects (ionization mainly by Compton effect in this case), are presented. This contribution was highlighted and quantified. Energetic, temporal and spatial beam characterizations (according to ISO 11554 standards) and LIDT tests were performed using a high power Nd: YAG laser (1064nm), before passing the beam through each irradiated glass sample (0kGy, 1.3kGy and 21.2kGy).
•The paper presents LIDT test results on gamma irradiated glasses.•The ISO 11554 and ISO 21254 Standards were used.•LIDT dependence to the exposure to strong nuclear fields was shown and quantified.
•The damage induced by gamma rays to optical materials was highlighted and quantified, using laser techniques.•Polarized light and the particularities of the laser light (monochromaticity, ...directionality and coherence) were used.•The correlation between the damage and the gamma rays absorbed dose was made.•The comparison between different types of optical materials and their dose related calibrations were made.•The uncertainty associated to the technique was determined.
Nuclear radiation induce some changes to the structure of exposed materials. The main effect of ionizing radiation when interacting with optical materials is the occurrence of color centers, which are quantitatively proportional to the up-taken doses. In this paper, a relation between browning effect magnitude and dose values was found. Using this relation, the estimation of a gamma radiation dose can be done. By using two types of laser wavelengths (532nm and 633nm), the optical powers transmitted thru glass samples irradiated to different doses between 0 and 59.1kGy, were measured and the associated optical browning densities were determined. The use of laser light gives the opportunity of using its particularities: monochromaticity, directionality and coherence. Polarized light was also used for enhancing measurements quality. These preliminary results bring the opportunity of using glasses as detectors for the estimation of the dose in a certain point in space and for certain energy, especially in particles accelerators experiments, where the occurred nuclear reactions are involving the presence of high gamma rays fields.
Almost all optical diagnostic systems associated with classical particle accelerators or with new state-of-the-art particle accelerators, such as those developed within the European Collaboration ...ELI-NP (Extreme Light Infrastructure-Nuclear Physics) (involving extreme power laser beams), contain in their infrastructure high quality laser mirrors, used for their reflectivity and/or their partial transmittance. These high quality mirrors facilitate the extraction and handling of optical signals. When optical mirrors are exposed to high energy ionizing radiation fields, their optical and structural properties will change over time and their functionality will be affected, meaning that they will provide imprecise information. In some experiments, being exposed to mixed laser and accelerated particle beams, the deterioration of laser mirrors is even more acute, since the destruction mechanisms of both types of beams are cumulated. The main task of the work described in this paper was to find a novel specific method to analyse and highlight such degradation processes. By using complex fractal techniques integrated in a MATLAB code, the effects induced by alpha radiation to laser mirrors were studied. The fractal analysis technique represents an alternative approach to the classical Euclidean one. It can be applied for the characterization of the defects occurred in mirrors structure due to their exposure to high energy alpha particle beams. The proposed method may be further integrated into mirrors manufacturing process, as a testing instrument, to obtain better quality mirrors (enhanced resistance to high energy ionizing beams) by using different types of reflective coating materials and different deposition techniques. Moreover, the effect of high energy alpha ionizing particles on the optical properties of the exposed laser mirrors was studied by using spectrophotometric techniques.
In this paper there are described three different algorithms of Minimum Detectable Activity (MDA) calculus, and its use in high resolution gamma spectrometry. In the first part, few introductive ...theoretical aspects related to the MDA are presented. Further, the theory was applied to real gamma rays spectrometry measurements and the results were compared with the activities reference values. Two different gamma spectrometry systems, both of them using High Purity Germanium (HPGe) detectors, but having different efficiencies, were used. Samples having different geometries and radionuclides content were measured. The measured samples were made by dissolving of some acids containing anthropogenic radionuclides in water, obtaining a density of 1g/cm3. Choosing this type of matrix was done because of its high homogeneity.
•Three different MDA algorithms were applied to gamma spectrometry measurements.•The measurements were performed using two HPGe detectors.•MDA performances of the two spectrometric systems were compared.•The measured samples had different geometries and contained a mixture of radionuclides.•MDA was studied also as a function of measuring time.
Obesity is a risk factor for the development of osteoarthritis (OA) in hands and knees. Adipose tissue can secrete different adipokines with powerful immunomodulatory effects. The infrapatellar fat ...pad (IFP) is an intra-articular organ in the vicinity of the synovium and cartilage. It is hypothesised that IFP-derived soluble factors could contribute to pathological processes in the knee joint. A study was therefore undertaken to compare the release of inflammatory mediators in the IFP and subcutaneous adipose tissue (ScAT) and to characterise the adipocytes and immune cell infiltrate in these tissues.
Paired IFP and ScAT samples were obtained from 27 patients with primary OA. The stromal vascular cell fraction (SVF) was isolated and characterised by fluorescence activated cell sorting. Cytokine and adipokine release in fat- and adipocyte-conditioned media was measured by luminex.
IFP secreted higher levels of inflammatory mediators such as interleukin 6 (IL-6), adipsin, adiponectin and visfatin than ScAT. This could be due to differences in the phenotype of adipocytes and/or in the composition and phenotype of the SVF cells. IFP adipocyte-conditioned media showed a trend towards more IL-6 and adipsin than ScAT. Moreover, the SVF fraction of IFP contained more cells/g tissue, a lower percentage of T cells and a higher percentage of mast cells than ScAT. In addition, T cells had a predominantly pro-inflammatory phenotype while macrophages had a mixed pro- and anti-inflammatory phenotype in the IFP.
There are profound differences in secreted inflammatory factors and immune cell composition between the IFP and ScAT. These data indicate that IFP-derived soluble mediators could contribute to pathophysiological processes in the OA knee joint.
Summary Objective To investigate the presence of mast cells in the osteoarthritic (OA) synovium and their association with clinical parameters in comparison with rheumatoid arthritis (RA) samples. ...Method Synovial tissues of 56 symptomatic OA and 49 RA patients were obtained. Two to three paraffin slides were used to quantify inflammation using haematoxylin and eosin (H&E) staining (synovitis score 0–9), and numbers of mast cells (per 10 high-power fields) using double immunofluorescence for CD117 and tryptase. Average scores per patient were used for analysis. Knee radiographs of OA patients were scored according to the Kellgren and Lawrence (KL) system and pain was determined in OA patients at baseline by visual analogue scale (VAS). Results Median (range) of mast cells was significantly higher in OA samples 45 (1–168) compared to RA samples 4 (1–47) ( P -value < 0.001), despite a lower median (range) synovitis score in OA (2.5 (0–6.0)) compared to 4.6 (0–8.0) in RA samples. The synovitis score was significantly correlated with the number of mast cells (in OA Spearman's rho ( P -value) 0.3 (0.023) and RA 0.5 ( P -value < 0.001)). Interestingly, we observed a trend towards an association between the number of mast cells and an increased KL-grade ( P -value 0.05) in OA patients, independently of synovitis. No associations were found with self-reported pain. Conclusion Prevalence of mast cells in OA synovial tissue is relatively high and associates with structural damage in OA patients, suggesting a role of mast cells in this disease.
Inter-comparison of commercial continuous radon monitors responses Radulescu, I.; Calin, M.R.; Luca, A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
01/2022, Letnik:
1021
Journal Article
Recenzirano
Odprti dostop
Indoor and outdoor (atmospheric) radon activity concentrations need to be measured as accurate as possible for radiation protection and for climate applications. Particularly radon concentrations ...below 100 Bq m −3, useful for the retrieval of radon prone areas and for atmospheric studies, still need a robust metrological chain to ensure their quality. Ones of the most common used commercial continuous radon monitors were compared here under slightly different environmental conditions. The measured data set were divided into two groups (< 100 Bq m −3 and ≥ 100 Bq m −3) to assess the monitors responses and their associated uncertainties. Nevertheless, these results should also to point out if commercial monitors are suitable for monitoring low atmospheric radon concentrations with an associated uncertainty of 10% (k=1). This work, carried out within the EMPIR 19ENV01 traceRadon project, aims to offer a starting point for the development of a future radon monitor as transfer standard to increase the metrological capabilities of atmospheric radon monitoring.
Summary Objective Although osteoarthritis (OA) is considered a non-inflammatory condition, it is widely accepted that synovial inflammation is a feature of OA. However, the role of immune cells and ...their cytokines in OA is largely unknown. This narrative systematic review summarizes the knowledge of inflammatory properties, immune cells and their cytokines in synovial tissues (STs) of OA patients. Design Broad literature search in different databases was performed which resulted in 100 articles. Results Of 100 articles 33 solely investigated inflammation in OA ST with or without comparison with normal samples; the remaining primarily focussed on rheumatoid arthritis (RA) ST. Studies investigating different severity stages or cellular source of cytokines were sparse. OA ST displayed mild/moderate grade inflammation when investigated by means of haematoxylin and eosin (H&E) staining. Most frequently found cells types were macrophages, T cells and mast cells (MCs). Overall the number of cells was lower than in RA, although the number of MCs was as high as or sometimes even higher than in RA ST. Cytokines related to T cell or macrophage function were found in OA ST. Their expression was overall higher than in normal ST, but lower than in RA ST. Their cellular source remains largely unknown in OA ST. Conclusion Inflammation is common in OA ST and characterized by immune cell infiltration and cytokine secretion. This inflammation seems quantitatively and qualitatively different from inflammation in RA. Further research is needed to clarify the role of inflammation, immune cells and their cytokines in the pathogenesis of OA.
Summary Objective To investigate the presence of inflammation and resolution pathways in osteoarthritis (OA). Design Tissues were obtained from knee OA patients and control rheumatoid arthritis (RA) ...patients. Cells in synovial fluid (SF) were visualized by flow cytometry. Cytokines and chemokines were measured by multiplex assay. Lipid mediators (LMs) were determined by targeted lipidomics using liquid-chromatography mass spectrometry. Results SF of OA patients contained less cells, especially neutrophils, less cytokines and comparable levels of chemokines compared to RA controls. Thirty-seven lipids were detected in the soluble fraction of SF, including polyunsaturated fatty acids (PUFAs) and their pro-inflammatory and pro-resolving lipoxygenase (LOX) and cyclooxygenase (COX) pathway markers in both OA and RA patients. Among these, pro-inflammatory LM such as prostaglandin E2 (PGE2 ) and thromboxane B2 , as well as precursors and pathway markers of resolution such as 17-HDHA and 18-HEPE were detected. Interestingly, the pro-resolving lipid RvD2 could also be detected, but only in the insoluble fraction (cells and undigested matrix). Ratios of metabolites to their precursors indicated a lower activity of 5-LOX and 15-LOX in OA compared to RA, with no apparent differences in COX-derived products. Interestingly, synovial tissue and SF cells could produce 5-LOX and 15-LOX metabolites, indicating these cells as possible source of LM. Conclusions By using a state-of-the-art technique, we show for the first time that resolution pathways are present in OA patients. A better understanding of these pathways could guide us to more effective therapeutic approaches to inhibit inflammation and further structural damage in OA and RA.
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