Activity

Locally extracted 4D SPECT patches (three spatial plus one energy dimension) were used as input for the CNN which was trained to predict the attenuation coefficient of the corresponding central voxel of the patch. Results show that Attenuation Correction using the Ground Truth [Formula see text] maps (GT-AC) or using the CNN estimated [Formula see text] maps (CNN-AC) achieve comparable accuracy. This was confirmed by a visual assessment as well as a quantitative comparison; the mean deviation from the GT-AC when using the CNN-AC is within 1.8% for the standardized uptake values in all brain regions. Therefore, our results indicate that a CNN-based method can be an automatic and accurate tool for SPECT attenuation correction that is independent of attenuation data from other imaging modalities or human interpretations about head contours.This work investigates the possible integration of an energy harvester in a bioinspired fish-like aquatic unmanned vehicle. The defined fish-like system utilizes a reduced complexity prescribed motion as the representation for energy harvester to be subjected to. Nonlinear electromechanical modeling is performed by considering the geometric and piezoelectric nonlinearities. A convergence analysis is carried out in order to determine the required modes in the Galerkin discretization due to the presence of nonlinear interactions between the prescribed and relative motions. The utilization of higher-order modeling for the strain and material leads to the identification of impactful prescribed motions terms that can activate the nonlinearities in the system, results in more harmonics to consider, and leads to the presence parametric excitation terms. Considering a reduced-complex model by decreasing the value of the quadratic constraint envelope that the fish-like system would be forced with, the soft-robotic system behaves more with a base excitation characteristic. Small damping would allow this prescribed motion with reduced quadratic envelope forcing still induces a hardening behavior, but the other harmonics and parametric resonance seen are greatly reduced. Considering this reduced complexity system, the interaction between the prescribed and base excitations is also investigated to demonstrate that when the two excitations are of similar nature constructive and destructive build of the response waveform can occur when looking at near the first natural resonance. It is shown that the quenching phenomenon can take place which may result in a destructive response of the piezoelectric energy harvester. The results show that the robustness of the fish-like robot is directly dependent on the design parameters including the damping of the structure, importance of the undulatory motion, and activation of the resonances.The response of Al2O3C optically stimulated luminescence detectors (OSLDs) was investigated in a 250 MeV pencil proton beam. The OSLD response was mapped for a wide range of average dose rates up to 9000 Gy s-1, corresponding to a ∼150 kGy s-1instantaneous dose rate in each pulse. Two setups for ultra-high dose rate (FLASH) experiments are presented, which enable OSLDs or biological samples to be irradiated in either water-filled vials or cylinders. The OSLDs were found to be dose rate independent for all dose rates, with an average deviation less then 1% relative to the nominal dose for average dose rates of (1-1000) Gy s-1when irradiated in the two setups. A third setup for irradiations in a 9000 Gy s-1pencil beam is presented, where OSLDs are distributed in a 3 × 4 grid. Calculations of the signal averaging of the beam over the OSLDs were in agreement with the measured response at 9000 Gy s-1. Furthermore, a new method was presented to extract the beam spot size of narrow pencil beams, which is in agreement within a standard deviation with results derived from radiochromic films. The Al2O3C OSLDs were found applicable to support radiobiological experiments in proton beams at ultra-high dose rates.The International Commission on Radiological Protection has recently published a report (ICRP Publication 147;Ann. ICRP50, 2021) on the use of dose quantities in radiological protection, under the same authorship as this Memorandum. Here, we present a brief summary of the main elements of the report. ICRP Publication 147 consolidates and clarifies the explanations provided in the 2007 ICRP Recommendations (Publication 103) but reaches conclusions that go beyond those presented in Publication 103. Further guidance is provided on the scientific basis for the control of radiation risks using dose quantities in occupational, public and medical applications. It is emphasised that best estimates of risk to individuals will use organ/tissue absorbed doses, appropriate relative biological effectiveness factors and dose-risk models for specific health effects. However, bearing in mind uncertainties including those associated with risk projection to low doses or low dose rates, it is concluded that in the context of radiological protection, effective dose may be considered as an approximate indicator of possible risk of stochastic health effects following low-level exposure to ionising radiation. TH5427 mouse In this respect, it should also be recognised that lifetime cancer risks vary with age at exposure, sex and population group. The ICRP report also concludes that equivalent dose is not needed as a protection quantity. Dose limits for the avoidance of tissue reactions for the skin, hands and feet, and lens of the eye will be more appropriately set in terms of absorbed dose rather than equivalent dose.Severe skin injuries, including burns, represent a real concern for the global health-care system and therefore, there is an increased interest in developing wound dressings, in order to stimulate and enhance skin tissue repair. The aim of this study was to design novel hybrid materials, biomimetic to skin extracellular matrix and enriched with silver nanoparticles (nAg), in order to provide both dermal tissue regeneration and antimicrobial activity. Two material variants (variant A and variant B) consisting of type I collagen (COL), chondroitin sulfate (CS) and k-elastin peptides (EL) enriched with positively-charged nAg, were conditioned as membranes. UV exposure ensured both sterilisation and cross-linking of the materials. Physico-chemical characterization of the hybrid biomaterials showed values of density and swelling degree higher than those of COL membrane, while the process of in vitro degradation followed a similar pattern. Infrared spectroscopy and X-ray diffraction indicated alterations of the characteristic structural features and crystallinity of COL after blending with CS and EL and nAg embedding.