STEPS TOWARD OPTIMIZING HPGe DETECTOR EFFICIENCY IN THE CONTEXT OF LOW-LEVEL RADIOACTIVITY DETECTION

Different empirical and theoretical methods are used to precisely determine radionuclide activity concentrations. This study used Monte Carlo simulation MCNP5 code and EFFTRAN software (Efficiency Transfer) to determine the HPGe detector Full-Energy Peak (FEP) efficiency. A set of point sources (133Ba,152Eu,137Cs,60Co, and22Na) fixed on the top of the standard geometry plastic container were measured in order to obtain the calibration curve. Because of the importance of chemical composition parameters, the detector behavior due to different matrices was investigated. Experimental verification of the calibration was obtained using IAEA-TEL-2021-03 quality control water sample spiked with152Eu and133Ba, and the results were compared with reported results. A set of Certified Standard Reference samples were used for method validation. The obtained results were compared with the experimental results. The comparison clarified the advantages and disadvantages of both methods and their precision to demonstrate and suitable method for matrix types. © 2023, Publishing House of the Romanian Academy. All rights reserved

Increased endothelin-1 and diminished nitric oxide levels in blister fluids of patients with intermediate cold type complex regional pain syndrome type 1

BACKGROUND: In complex regional pain syndrome type 1 (CRPS1) pro-inflammatory mediators and vascular changes play an important role in the sustained development and outcome of the disease. The aim of this study was to determine the involvement of vasoactive substances endothelin-1 (ET-1) and nitric oxide (NO) during early chronic CRPS1. METHODS: Included were 29 patients with CRPS 1 who were diagnosed during the acute stage of their disease and observed during follow-up visits. Disease activity and impairment were determined and artificial suction blisters were made on the CRPS1 and the contralateral extremities for measurements of IL-6, TNF-α, ET-1 and nitrate/nitrite (NOx). RESULTS: The levels of IL-6, TNF-α and ET-1 in blister fluid in the CRPS1 extremity versus the contralateral extremity were significantly increased and correlated with each other, whereas NOx levels were decreased. CONCLUSION: The NOx/ET-1 ratio appears to be disturbed in the intermediate stage of CRPS, resulting in vasoconstriction and consequently in a diminished tissue blood distribution

Regulation of peripheral blood flow in Complex Regional Pain Syndrome: clinical implication for symptomatic relief and pain management

Background. During the chronic stage of Complex Regional Pain Syndrome (CRPS), impaired microcirculation is related to increased vasoconstriction, tissue hypoxia, and metabolic tissue acidosis in the affected limb. Several mechanisms may be responsible for the ischemia and pain in chronic cold CPRS. Discussion. The diminished blood flow may be caused by either sympathetic dysfunction, hypersensitivity to circulating catecholamines, or endothelial dysfunction. The pain may be of neuropathic, inflammatory, nociceptive, or functional nature, or of mixed origin. Summary. The origin of the pain should be the basis of the symptomatic therapy. Since the difference in temperature between both hands fluctuates over time in cold CRPS, when in doubt, the clinician should prioritize the patient's report of a persistent cold extremity over clinical tests that show no difference. Future research should focus on developing easily applied methods for clinical use to differentiate between central and peripheral blood flow regulation disorders in individual patients

Reactive single-step hot-pressing and magnetocaloric performance of polycrystalline Fe2Al1.15−xB2GexGax (x = 0, 0.05) MAB phases

Reactive single-step hot-pressing at 1473 K and 35 MPa for 4 h produces dense, bulk, near single-phase, low-cost, and low-criticality Fe2Al1.15B2 and Fe2Al1.1B2Ge0.05Ga0.05 MAB samples, showing second-order magnetic phase transition with favorable magnetocaloric properties around room temperature. The magnetic as well as the magnetocaloric properties can be tailored upon Ge and Ga doping, leading to an increase in the Curie temperature TC and the spontaneous magnetization mS. The maximum isothermal entropy change ΔsT, max of hot-pressed Fe2Al1.15B2 in magnetic field changes of 2 and 5 T amounts to 2.5 and 5 J(kgK)−1 at 287.5 K and increases by Ge and Ga addition to 3.1 and 6.2 J(kgK)−1 at 306.5 K, respectively. The directly measured maximum adiabatic temperature change ΔTad, max is improved by composition modification from 0.9 to 1.1 K in magnetic field changes of 1.93 T. Overall, we demonstrate that hot-pressing provides a much faster, more scalable, and processing costs reducing alternative compared to conventional synthesis routes to produce heat exchangers for magnetic cooling devices. Therefore, our criticality assessment shows that hot-pressed Fe-based MAB phases provide a promising compromise of material and processing costs, criticality, and magnetocaloric performance, demonstrating the potential for low-cost and low-criticality magnetocaloric applications around room temperature