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• Pub. Date : 2025
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A small modular reactor (SMR) has been considered a potential alternative for achieving carbon neutrality, and therefore, an increasing number of countries are performing extensive research and development. However, this is still in the development stage, and there are several technological or economical challenges that need to be overcome. Minimizing manual operations may be considered a wise approach to reduce the number of operators.Reactor core startup, which is a manual operation, is considered as an example. A method to automate the reactor core startup via the reinforcement learning (RL) algorithm is proposed in this paper. Further, an efficient SMR dynamic simulation model that performs simulations considering the action of the RL agent to achieve states and reward is developed. The suggested SMR dynamic simulation model is validated by the data available in the existing literature. The proposed method can perform automatic reactor core startup. The proposed framework that incorporates the SMR simulator to the RL algorithm is expected to be applied to various cases for reducing manual operations and contributing to realizing a higher level of SMR automation

• Book : 57(3)
• Pub. Date : 2025
• Page : pp.1-15
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AbstractProtein domains of low sequence complexity are unable to fold into stable, three-dimensional structures. In test tube studies, these unusual polypeptide regions can self-associate in a manner causing phase separation from aqueous solution. This form of protein:protein interaction has been implicated in numerous examples of dynamic morphological organization within eukaryotic cells. In several cases, the basis for low complexity domain (LCD) self-association and phase separation has been traced to the formation of labile cross-β structures. The primary energetic force favoring formation of these transient and reversible structures is enabled by polypeptide backbone interactions. Short, contiguous networks of peptide backbone amino groups and carbonyl oxygens are zippered together intermolecularly by hydrogen bonding as described by Linus Pauling seven decades ago. Here we describe a simple, molecular biological method useful for the identification of localized, self-associating regions within larger protein domains of low sequence complexity.SignificanceThis study describes a molecular biological method for analyzing protein domains of low sequence complexity in search of segments that mediate self-association and consequent phase separation bothin vitroandin vivo. Small regions allowing for self-association correspond to sequences that specify the formation of labile cross-β structural order. When juxtaposed to the C-terminus of GFP, cross-β prone regions suppress fluorescence. A tiled scan of overlapping fragments of the low complexity domain (LCD) of the TDP-43 RNA binding protein pinpointed an evolutionarily conserved sequence of twenty amino acids essential for self-association, phase separation and the formation of nuclear speckles. The screening method described herein should be useful for the analysis of any LCD believed to function via homotypic self-association.

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• Pub. Date : 2025
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Introduction. A significant shortage of high-quality donor organs remains one of the most pressing challenges, especially when it comes to extended criteria donors or asystolic donors. The solution to this problem arises at the intersection of surgical skill, advanced biomedical technologies and a deep understanding of the mechanisms of ischemia-reperfusion injury (IRI). Objective. This study was carried out to substantiate and refine the technique of extracorporeal ex-vivo perfusion of a liver graft on an animal model using the Ex-Stream perfusion apparatus for extracorporeal oxygenation according to TU 32.50.21-002-75538036-2020 (RU holder Transbiotek LLC, St. Petersburg, Russia, manufacturer Biosoft-M LLC, Moscow, Russia). Materials and methods. The study was conducted on male pigs weighing 15–30 kg (n = 5). The study is based on the analysis of the results of hypothermic oxygenated perfusion of the liver transplant in a vivarium using a cardiopulmonary bypass apparatus. The study was conducted according to the following protocol: the donor liver was removed from the animal with the formation of a temporary venovenous bypass, pharmaco-cold preservation of the organ using the Ex-Stream apparatus and its subsequent replantation. Results. The following results were obtained in a series of 5 observations. Tissue damage markers (AST, ALT, LDH, GGTP) showed a gradual increase in their level in the perfusate over the course of ischemia. The average values of AST and ALT increased by 2-3 times, LDH - by 1.5-2 times, and GGTP - by 1.2-1.5 times compared to the initial values. The level of malondialdehyde, reflecting oxidative stress, increased by an average of 30–40% by the end of the experiment, while the level of glutathione decreased by 20–25%. Concentrations of proinflammatory cytokines (TNF-α, IL-6, IL-1β) in the perfusate increased 2–4 times compared to baseline values, indicating the development of an inflammatory response. Microscopic examination with hematoxylin and eosin staining revealed signs of ischemic damage to hepatocytes, such as cytoplasmic vacuolization, nuclear pyknosis, and disruption of the beam structure. The degree of damage increased with increasing ischemia time. Mason staining showed a moderate increase in connective tissue in the portal tracts and pericentral zones, indicating initial fibrotic changes. Ultramicroscopic examination (transmission electron microscopy) revealed swelling of mitochondria, disruption of the integrity of their cristae, expansion of the endoplasmic reticulum and formation of autophagosomes in hepatocytes. Oxygen consumption by liver tissue gradually decreased during the experiment, reaching 60-70% of the initial level by the end of the observation. Carbon dioxide production also decreased, but to a lesser extent, amounting to 75-85% of the baseline values. Analysis of the perfusate using a potentiostat-galvanostat IPS showed a gradual decrease in the oxidation-reduction potential, indicating an increase in hypoxia and depletion of antioxidant reserves. The activity of superoxide dismutase and catalase, key antioxidant enzymes, decreased by 30-40% and 20- 30%, respectively, compared with the initial values, indicating a weakening of the antioxidant defense. Conclusion. The obtained results indicate that the developed model using the Ex-Stream device is reproducible and allows for effective study of the state of ischemia-reperfusion injury. This opens up opportunities for conducting a larger and more comprehensive series of experiments, the results of which will be the subject of our further research.

• Book : 14(6)
• Pub. Date : 2025
• Page : pp.159-170
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• Pub. Date : 2025
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AbstractIn this paper, the effect of gamma‐ray irradiation on the electrical conductivity of polypropylene (PP) composites has been studied. The samples are prepared using PP and styrene–ethylene–butylene–styrene elastomer with contents ranging from 0 wt% to 50 wt%, and exposed to Cobalt‐60 gamma irradiation, with a dose from 0 to 250 kGy. Electrical conductivities at different temperatures and trap distributions are measured to observe the deterioration of insulation performance. The microstructure of the sample is estimated using differential scanning calorimetry, X‐ray diffraction, thermogravimetric analysis and a scanning electron microscope. The obtained results demonstrate a correlation between the increase in electrical conductivity and the elevation in both total dose and temperature. At 250 kGy, the trap distribution tends to become shallower, accompanied by a decrease in crystallinity, melting and decomposition temperatures of the sample. The PP composite exhibits better stability against irradiation and thermal effects, primarily due to the cross‐linked structures formed by irradiation.

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• Pub. Date : 2025
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Abstract Background Accurately predicting the malignant risk of ground-glass nodules (GGOs) is crucial for precise treatment planning. This study aims to utilize convolutional neural networks based on dual-time-point 18F-FDG PET/CT to predict the malignant risk of GGOs. Methods Retrospectively analyzing 311 patients with 397 GGOs, this study identified 118 low-risk GGOs and 279 high-risk GGOs through pathology and follow-up according to the new WHO classification. The dataset was randomly divided into a training set comprising 239 patients (318 lesions) and a testing set comprising 72 patients (79 lesions), we employed a self-configuring 3D nnU-net convolutional neural network with majority voting method to segment GGOs and predict malignant risk of GGOs. Three independent segmentation prediction models were developed based on thin-section lung CT, early-phase 18F-FDG PET/CT, and dual-time-point 18F-FDG PET/CT, respectively. Simultaneously, the results of the dual-time-point 18F-FDG PET/CT model on the testing set were compared with the diagnostic of nuclear medicine physicians. Results The dual-time-point 18F-FDG PET/CT model achieving a Dice coefficient of 0.84 ± 0.02 for GGOs segmentation and demonstrating high accuracy (84.81%), specificity (84.62%), sensitivity (84.91%), and AUC (0.85) in predicting malignant risk. The accuracy of the thin-section CT model is 73.42%, and the accuracy of the early-phase 18F-FDG PET/CT model is 78.48%, both of which are lower than the accuracy of the dual-time-point 18F-FDG PET/CT model. The diagnostic accuracy for resident, junior and expert physicians were 67.09%, 74.68%, and 78.48%, respectively. The accuracy (84.81%) of the dual-time-point 18F-FDG PET/CT model was significantly higher than that of nuclear medicine physicians. Conclusions Based on dual-time-point 18F-FDG PET/CT images, the 3D nnU-net with a majority voting method, demonstrates excellent performance in predicting the malignant risk of GGOs. This methodology serves as a valuable adjunct for physicians in the risk prediction and assessment of GGOs.

• Book : 25(1)
• Pub. Date : 2025
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• Pub. Date : 2025
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