AbstractPlutonium was discovered and first synthesized in the early 1940's. Several isotopes of plutonium are used in nuclear technologies, 238Pu for heat generation and 239Pu for energy production and weapons. Both isotopes emit alpha particles, which pose a significant radiation hazard when incorporated into the body. Alpha particles emitted during 239Pu decay deposit energy along a very short path in biological tissues (≈45 μm in soft tissues). Thus, defining the anatomical locations of these deposits is essential to identify the cells at risk of radiation damage and potential malignant transformation. Bone is a primary site for plutonium deposition and retention. Plutonium exposures are associated with increases in osteogenic cancers. Plutonium is preferentially deposited on endosteal and endocortical bone surfaces, particularly those surrounded by red versus yellow bone marrow. Red marrow is more vascularized with a sinusoid network, while yellow marrow is largely a closed capillary system. Cancellous bone in red marrow sites has greater bone turnover rates and relatively more plutonium‐related bone cancers than in yellow marrow sites. The relationships of plutonium deposits in bone and potential alpha particle exposures to cells that include osteoclasts, reversal cells, canopy cells, osteoblasts, bone lining cells, and osteogenic progenitors of the basic multicellular unit during bone modeling and remodeling are reviewed. Differences in distributions of 239Pu versus naturally occurring tumors in humans and experimental animals are noted. This review emphasizes the importance of the anatomical locations of plutonium deposition and retention in the skeleton and the potential relative radiation risks from alpha particles to bone cells and their progenitors.

• Book : ()
• Pub. Date : 2025
• Page :
• Keyword :

Serial crystallography (SX) enables the determination of biologically relevant structures at room temperature while minimizing radiation damage. During SX experiments, the beam center on diffraction images can shift due to X-ray beam movements or detector displacement. Consequently, the geometry file for the beam center is optimized; however, the effects of deviations from the optimal position on data processing efficiency remain unclear. This study examines how changes in the beam center influence data quality by analyzing the indexing efficiency and structure refinement of lysozyme and glucose isomerase datasets, considering shifts in the beam center parameter. The results revealed that as the beam center deviated farther from its optimal position, the indexing efficiency declined, with the extent of the effect varying significantly across indexing algorithms. XDS and MOSFLM algorithms maintained high indexing efficiencies (>90%) for shifts of ≤4 pixels (688 μm) and ≤2 pixels (344 μm), respectively, compared to data processed at the optimized beam center. Conversely, the DirAx and XGANDALF algorithms exhibited indexing efficiencies below 90% for a two-pixel shift in the beam center. These findings enhance our understanding of how beam center shifts affect SX data processing and provide valuable insights for developing effective data processing strategies.

• Book : 15(2)
• Pub. Date : 2025
• Page : pp.185-185
• Keyword :

Abstract A new, simple and robust design for a gas proportional scintillation counter (GPSC) is studied. One sole electrode, the anode, is used to define the electric field in the drift and scintillation regions of the detector volume. The anode has an annular shape aligned with the photosensor axis. Such design allows to keep constant the solid angle subtended by the photosensor relative to the different positions of the scintillation region. Having an oblong anode with a 10 cm inner diameter and a 5 cm photomultiplier tube placed 5 cm below the anode, an energy resolution of 12.0 % FWHM has been achieved for a 10 kV anode bias, the maximum voltage that could be applied to the anode in the present prototype. According to simulations, energy resolutions of ~10 % can be achieved for anode voltages of ~13 kV, a value comparable to the 9–10 % achieved in GPSC using solid angle variation compensation. Independently of having a constant solid angle, the absolute value of the solid angle must be considered, a lower number of EL photons detected at the photosensor due to a reduced solid angle may contribute to the GPSC energy resolution degradation. In addition, non-uniformities present in the photosensor or in the GPSC must be taken into account, since they will contribute to a dependence of the pulse amplitude on the radiation interaction position despite the constant solid angle subtended by the photosensor relative to the scintillation region.

• Book : 20(02)
• Pub. Date : 2025
• Page : pp.C02021-C02021
• Keyword :

New higher-count-rate, integrating, large-area X-ray detectors with framing rates as high as 17400 images per second are beginning to be available. These will soon be used for specialized macromolecular crystallography experiments but will require optimal lossy compression algorithms to enable systems to keep up with data throughput. Some information may be lost. Can we minimize this loss with acceptable impact on structural information? To explore this question, we have considered several approaches: summing short sequences of images, binning to create the effect of larger pixels, use of JPEG-2000 lossy wavelet-based compression, and use of Hcompress, which is a Haar-wavelet-based lossy compression borrowed from astronomy. We also explore the effect of the combination of summing, binning, and Hcompress or JPEG-2000. In each of these last two methods one can specify approximately how much one wants the result to be compressed from the starting file size. These provide particularly effective lossy compressions that retain essential information for structure solution from Bragg reflections.

• Book : 32(2)
• Pub. Date : 2025
• Page :
• Keyword :

• Book : ()
• Pub. Date : 2025
• Page :
• Keyword :

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
• Keyword :

As small modular reactors continue to advance, heat pipe reactors (HPRs) are being developed by multiple organizations.Designing heat pipes with optimal heat transfer capability is crucial for the effective performance of HPRs. Based on NSGA-III genetic algorithm, this paper presented the design method of a high-temperature heat pipe featuring a composite wick. The study examined the influence of heat pipe structure parameters on performance parameters and heat transfer limits. Based on the analysis, we built multi-objective modeling of heat pipe and obtained the optimal structural parameters by NSGA-III. Verification confirmed that the heat pipe met the Mach number and effective capillary radius requirements. This study provided valuable insights for improving heat pipe manufacturing techniques and reactor miniaturization.

• Book : 57(3)
• Pub. Date : 2025
• Page : pp.1-11
• Keyword :

Plasmopara viticola causes grape downy mildew, one of the most notorious diseases of cultivated grapes that damage vineyards worldwide. The pathogen secretes various effector molecules to infect and modulate the host biological processes. In this study, we aimed to evaluate the roles of KPvRxLR27, an arginine–any amino acid–leucine–arginine (RxLR) effector isolated from P. viticola JN-9 from Jeonju (South Korea) with respect to the reported Bcl-2-associated X and inverted formin1in inducing cell death in non-host Nicotiana benthamiana and resistant grape host cultivars via Agrobacterium-mediated transient transformation. We found that, KPvRxLR27 induced programmed cell death in N. benthamiana and rapid hypersensitive response in resistant grape cultivars. Agroinfiltration assay revealed that putative N-glycosylation at the N¹⁸⁶ amino acid sequence and nuclear localization signal motifs at the C-terminus were critical for the effector’s cell death-inducing activity of KPvRxLR27. Overexpression assay revealed that KPvRxLR27 was abundantly expressed in the plasma membrane and nuclear regions and activated the accumulation of reactive oxygen species in N. benthamiana. Moreover, KPvRxLR27 expression was significantly delayed in the resistant cultivar than in the susceptible cultivar. Our results suggest KPvRxLR27 as a potential avirulence gene recognized by the host receptors to activate the host immune response-associated genes, providing valuable insights to enhance the pathogen resistance of commercial cultivars.

• Book : 41(1)
• Pub. Date : 2025
• Page : pp.28-37
• Keyword :

Abstract The Reissner–Weyl–Nordström (RWN) spacetime of a point nucleus features a naked singularity for the empirically known nuclear charges Ze and masses $$M = A(Z,N)m_{\textrm{p}}$$ M = A ( Z , N ) m p , where $$m_{\textrm{p}}$$ m p is the proton mass and $$A(Z,N)\approx Z+N$$ A ( Z , N ) ≈ Z + N the atomic mass number, with Z the number of protons and N the number of neutrons in the nucleus. The Dirac Hamiltonian for a test electron with mass $$m_{\textrm{e}}$$ m e , charge $$-\,e$$ - e , and anomalous magnetic moment $$\mu _a (\approx -\, \frac{1}{4\pi }\frac{e^3}{m_{\textrm{e}}c^2})$$ μ a ( ≈ - 1 4 π e 3 m e c 2 ) in the electrostatic RWN spacetime of such a “naked point nucleus” is known to be essentially self-adjoint, with a spectrum that consists of the union of the essential spectrum $$(-\,\infty ,-\,m_{\textrm{e}}c^2]\cup [m_{\textrm{e}}c^2, \infty )$$ ( - ∞ , - m e c 2 ] ∪ [ m e c 2 , ∞ ) and a discrete spectrum of infinitely many eigenvalues in the gap $$(-\,m_{\textrm{e}}c^2,m_{\textrm{e}}c^2)$$ ( - m e c 2 , m e c 2 ) , having $$m_{\textrm{e}}c^2$$ m e c 2 as accumulation point. In this paper, the discrete spectrum is characterized in detail for the first time, for all $$Z\le 45$$ Z ≤ 45 and A that cover all known isotopes. The eigenvalues are mapped one-to-one to those of the traditional Dirac hydrogen spectrum. Numerical evaluations that go beyond $$Z=45$$ Z = 45 into the realm of not-yet-produced hydrogenic ions are presented, too. A list of challenging open problems concludes this publication.

• Book : ()
• Pub. Date : 2025
• Page :
• Keyword :

• Book : ()
• Pub. Date : 2025
• Page :
• Keyword :