Depleted Uranium Research Articles

MSC-EXs inhibits uranium nephrotoxicity by competitively binding key proteins and inhibiting ROS production.

Uranium poisoning, particularly from exposure to Depleted Uranium (DU), occurs when uranyl ions enter the bloodstream and bind primarily to transferrin, osteopontin, and albumin before entering cells via corresponding receptors on renal tubular membranes, leading to cellular damage. Uranium poisoning remains a significant clinical challenge, with no ideal treatment currently available. In this study, we investigate the therapeutic potential of human umbilical cord-derived mesenchymal stem cell exosomes (MSC-EXs) in mice exposed to DU. Our results showed that MSC-EXs could ameliorate renal damage and enhance kidney and bone marrow morphology but also effectively promote uranium excretion while reducing internal retention. Notably, the protective effects of MSC-EXs exceed those of MSCs and are comparable to those of sodium bicarbonate, as confirmed by various analytical techniques. Proteomic studies have shown that MSC-EXs reduce uranyl ion deposition in renal tubule cells through competitive binding with transferrin, osteopontin, and albumin. They also enhance oxidative stress resistance via modulation of glutathione metabolism, Cysteine and Methionine metabolism signaling pathways. This regulation leads to a reduction in mitochondrial ROS production, alleviates lipid peroxidation, and consequently decreases cellular apoptosis and ferroptosis. This study identifies MSC-EXs as a novel therapeutic strategy against depleted uranium poisoning, presenting potential advancements in treatment methodologies.

Mitigation of depleted uranium-induced mitochondrial damage by ethylmalonic encephalopathy 1 protein via modulation of hydrogen sulfide and glutathione pathways.

Depleted uranium (DU) is a byproduct of uranium enrichment, which can cause heavy-metal toxicity and radiation toxicity as well as serious damage to the kidneys. However, the mechanism of renal injury induced by DU is still unclear. This study aimed to explore the role of ethylmalonic encephalopathy 1 (ETHE1) in DU-induced mitochondrial dysfunction and elucidate the underlying mechanisms. Using ETHE1 gene knockout C57BL/6 mice (10mg/kg DU) and renal cell models (500µM DU) exposed to DU, we observed significantly reduced levels of hydrogen sulfide (H2S) and glutathione (GSH), alongside decreased adenosine triphosphate (ATP) content and increased oxidative stress. Our results demonstrated that knocking out or silencing ETHE1 led to a significant reduction in H2S and GSH levels, whereas the opposite occurred when was ETHE1 overexpressed. When the H2S donor sodium hydrosulfide and GSH precursor N-acetylcysteine were used to treat animals or cells, cellular ATP levels were increased, oxidative stress markers were reduced, and kidney damage was mitigated. In addition, H2S and GSH interacted with each other after DU poisoning. These findings suggest that the ETHE1/H2S/GSH pathway plays a critical role in mediating DU-induced mitochondrial dysfunction in renal cells, highlighting potential therapeutic targets for mitigating the harmful effects of DU. Thus, this study expands our understanding of DU-induced renal damage pathways, providing avenues for further research and intervention strategies.

Verification of uranium composite materials using active interrogation techniques for safeguards purposes

Abstract The uranium isotope characterization for nuclear safeguards and security purposes was conducted using both passive and active non-destructive techniques. The interrogated samples were natural uranium (NU), low-enriched uranium (LEU), and depleted uranium (DU) all in the form of uranium dioxide. The obtained spectra using both techniques were accumulated using a high-efficiency HPGe detector. Improving detector efficiency was developed using the neural network (NN) method based on the obtained intrinsic calibration data. The obtained enrichment results of passive measurements showed good agreement with certified samples to within 1.12% in the case of LEU, 1.03% in the case of NU, and 1.04% in the case of DU.
Active interrogation of the samples was done using the neutron spectrum of a 5 Ci 241Am-Be neutron source. Seven short-lived fission products (FPs) (101Tc, 97Nb, 105Ru, 92Y, 91Sr, 92Sr, and 88Kr) were chosen as indicators to provide a complete characterization of isotopic mass determination, uranium content, and enrichment. Isotopic masses of the samples were calculated using thermal and fast interrogations. A comparison of the obtained results of 238U mass was found to agree within 0.2% with certified value based on fast interrogation, and within 0.3% of 235U mass based on thermal interrogation.

Implication of depleted uranium in human carcinogenesis with a glance to implementation of novel and reliable experimental models

The recent acknowledgement of depleted uranium (DU) munitions utilization in the Ukrainian conflict has sparked renewed apprehensions regarding the safety of DU, its toxicological profile, and the health ramifications of exposure. Historical data from conflicts like the Gulf War, Bosnia, and Kosovo have recorded an upsurge in neoplastic ailments among soldiers in close proximity to DU deployment. Nevertheless, establishing a direct causal connection between DU exposure and the development of neoplastic diseases remains elusive, as indicated by meta-analyses and studies on animal models. We posit that the absence of a conclusive causal correlation between DU exposure and neoplastic diseases may be ascribed to the constraints of current study models, which fail to encapsulate the intricate interactions between DU and the human immune system, pathophysiology, particularly in the context of chronic, low-level exposure. Nowadays evidences suggests that DU exposure contributes to a cumulative immunotoxic effect, culminating in a compromised immune surveillance system and an escalated risk of neoplastic diseases over time. To investigate this hypothesis, we advocate for the advancement of pioneering research models, such as human ex-vivo body-on-a-chip systems, which can more accurately replicate the human physiological response to DU exposure and cancer pathophysiology. These models should encompass the examination of immune system modifications along with the potential for DU to interact with diverse organs and tissues, thereby furnishing a more comprehensive understanding of the enduring health impacts of DU.

Mitochondrial-Targeting Mesoporous Polydopamine Nanoparticles for Reducing Kidney Injury Caused by Depleted Uranium.

Depleted uranium (DU), when accidentally released from the nuclear industry, can enter the human body and cause kidney damage, as DU induces oxidative damage and apoptosis through mitochondrial pathways and inflammatory reactions. The existing nanoparticles used to treat DU injury have low bioavailability and poor targeting. In this study, mesoporous polydopamine (MPDA), poly-(ethylene glycol) (PEG), and triphenylphosphonium (TPP) are combined to develop a novel mitochondrion-targeting bifunctional nanoparticle, MPDA-PEG-TPP, and confirm that it can protect the kidneys from DU. This study demonstrates the high selectivity of MPDA-PEG-TPP for uranyl in uranyl chelate assays and its promising efficiency in uranyl sequestration from the kidneys, lungs, and femurs, following immediate or delayed administration of MPDA-PEG-TPP nanoparticles. In vitro assays confirm its efficiency in removing reactive oxygen species and targeting the mitochondria. In addition, in vitro and in vivo assays confirm that MPDA-PEG-TPP can reduce mitochondrial dysfunction and ameliorate kidney injury. These results suggest that MPDA-PEG-TPP is a valuable agent for ameliorating the DU-induced kidney injury.

Health Implications of Depleted Uranium: An Update.

Depleted uranium (DU), as a heavy metal material extensively utilized in the industrial sector, poses potential health risks to humans through various exposure pathways, including inhalation, ingestion, and dermal contact. To comprehensively understand the toxicological hazards of DU, this study conducted a literature search in the Web of Science Core Collection database using "DU" and "toxicity" as keywords, covering the period from January 2000 to December 2023. A total of 65 papers related to human, animal, or cellular studies on DU were included. This review delves into the latest research advancements on the origin and toxicokinetics of DU, as well as its pulmonary toxicity, neurotoxicity, nephrotoxicity, immunotoxicity, hepatotoxicity, reproductive toxicity, cancer, bone toxicity, and hematological toxicity. The aim of this review is to gain a deeper understanding of the health hazards posed by DU, which is of significant importance for formulating corresponding protection strategies and measures.

Closing the nuclear fuel cycle: Strategic approaches for NuScale-like reactor

The present study proposes the potential implementation of eight different closed fuel cycle strategies for a NuScale-like reactor core using its own spent fuel as a reusable source of fissile material for energy production. For that, the spent fuel composition after three burnup cycles of approximately 12 MWd/kgU of NuScale-like initial core and five years of cooling in a spent fuel pool was theoretically reprocessed by GANEX or UREX+ methods. After reprocessing, these two new fuel compositions were spiked in a mixture of thorium (Th) or depleted uranium (DpU), and afterwards inserted into specific batch positions of the core. Therefore, the proposed NuScale-like core configurations contain fuel assemblies loaded with conventional uranium-based fuel and others loaded with reprocessed fuel, resulting in the following combinations: UO2 and GANEX spiked with Th, UO2 and GANEX spiked with DpU, UO2 and UREX+ spiked with Th, UO2 and UREX+ spiked with DpU. The main idea is to comprehend the advantages of adopting the closed nuclear fuel cycle for a NuScale-like reactor by comparing the reference case and the cases containing reprocessed fuel. The results exhibited that all instances in which the core was simulated with reprocessed fuel improved the feedback coefficient, maximum excess of reactivity varying the boron concentration in the coolant, and power peak factor (PPF). Furthermore, the closed nuclear fuel strategies also demonstrated savings of about 17.50% in terms of separating work units (SWU) due to plutonium and uranium recycling, and a potential burnup extension of approximately 43%. The Serpent code version 2.1.32 developed by VTT and ENDF/B-VII.0 nuclear data library has been used to perform the simulations.

High-yield implosion modeling using the Frustraum: Assessing and controlling the formation of polar jets and enhancing implosion performance with applied magnetization

Frustraums have a higher laser-to-capsule x-ray radiation coupling efficiency and can accommodate a large capsule, thus potentially generating a higher yield with less laser energy than cylindrical Hohlraums for a given Hohlraum volume [Amendt et al., Phys. Plasmas 26, 082707 (2019]. Frustraums are expected to have less m = 4 azimuthal asymmetries arising from the intrinsic inner-laser-beam geometry on the National Ignition Facility. An experimental campaign at Lawrence Livermore National Laboratory to demonstrate the high-coupling efficiency and radiation symmetry tuning of the Frustraum has been under way since 2021. Simulations benchmarked against experimental data show that implosions using Frustraums can achieve more yield with higher ignition margins than cylindrical Hohlraums using the same laser energy. Hydrodynamic jets in capsules along the Hohlraum axis, driven by radiation-flux asymmetries in a Hohlraum with a gold liner on a depleted uranium (DU) wall, are present around stagnation, and these “polar” jets can cause severe yield degradation. The early-time Legendre mode P4<0 radiation-flux asymmetry is a leading cause of these jets, which can be reduced by using an unlined DU Hohlraum because the shape of the shell is predicted to be more prolate. Magnetization can increase the implosion robustness and reduce the required hotspot ρR for ignition; therefore, magnetizing the Frustraum can maintain the same yield while reducing the required laser energy or increase the yield using the same laser energy—all under the constraint that the ignition margin is preserved. Reducing polar jets is particularly important for magnetized implosions because of the intrinsic toroidal hotspot ion temperature topology.

Migration of depleted uranium from a corroded penetrator in soil vadose zone in Bosnia and Herzegovina

Depleted uranium (DU) from corroded armor penetrators can migrate through the soil vadose zone and cause environmental problems, yet studies on such migration at former theatres of war are scarce. Here, we investigated vertical DU migration in a soil profile due to a penetrator (3–8 cm beneath the soil surface) corroded over 7 years in Bosnia and Herzegovina. The highest concentration of DU was ∼45,300 mg/kg at 6–10 cm, with the concentration decreasing markedly with increasing depth. The majority of the DU accumulated within the top 20 cm and the DU front reached ∼42 cm beneath the penetrator. In addition, particles with varying U concentrations (3–65 wt%) were observed at 0–15 cm, with U primarily co-located with O, Si, Al, maghemite, and hematite. Particularly, metaschoepite was identified at 6–10 cm. Finally, X-ray absorption spectroscopy analysis found U was hexavalent in the soil profile. These findings suggest that the downward migration of DU was likely present as a soluble form adsorbed on clay minerals and Fe oxides. Overall, we show that the rate of DU migration within the vadose zone is comparatively slow, although if the penetrator is left in the soil for decades, it could pose a serious long-term risk. Environmental ImplicationsOver 90 % of the depleted uranium (DU) penetrators fired in previous conflicts missed their armored targets and were left in the soil to corrode. The corroded penetrators can not only contaminate soil but also pose a risk to groundwater. The present study examined the migration of DU in a soil profile that included a DU penetrator that had been corroding for over 7 years. Studying the dynamics of DU migration is essential to develop effective remediation strategies to mitigate long-term environmental risks and safeguard ecosystems and human health from DU contamination.

Release of Radioactive Particles to the Environment.

When environmental impact and risks associated with radioactive contamination of ecosystems are assessed, the source term and deposition must be linked to ecosystem transfer, biological uptake and effects in exposed organisms. Thus, a well-defined source term is the starting point for transport, dose, impact and risk models. After the Chornobyl accident, 3-4 tons of spent nuclear fuel were released and radioactive particles were important ingrediencies of the actual source term. As Chornobyl particles were observed in many European countries, some scientists suggested that radioactive particles were "a peculiarity of the Chornobyl accident." In contrast, research over the years has shown that a major fraction of refractory elements such as uranium (U) and plutonium (Pu) released to the environment has been released as particles following a series of past events such as nuclear weapons tests, non-criticality accidents involving nuclear weapons, military use of depleted uranium ammunition, and nuclear reactor accidents. Radioactive particles and colloids have also been observed in discharges from nuclear installations to rivers or to regional seas and are associated with nuclear waste dumped at sea. Furthermore, radioactive particles have been identified at uranium mining and tailing sites as well as at other NORM sites such as phosphate or oil and gas industrial facilities. Research has also demonstrated that particle characteristics such as elemental composition depend on the emitting source, while characteristics such as size distribution, structure, and oxidation state influencing ecosystem transfer will also depend on the release scenarios. Thus, access to advanced particle characteristic techniques is essential within radioecology. After deposition, localized heterogeneities such as particles will be unevenly distributed in the environment. Thus, inventories can be underestimated, and impact and risk assessments of particle contaminated areas may suffer from unacceptable large uncertainties if radioactive particles are ignored. The present paper will focus on key sources contributing to the release of radioactive particles to the environments, as well as linking particle characteristics to ecosystem behavior and potential biological effects.

Hedgehog pathway negatively regulated depleted uranium-induced nephrotoxicity.

Depleted uranium (DU) retains the radiological toxicities, which accumulates preferentially in the kidneys. Hedgehog (Hh) pathway plays a critical role in tissue injury. However, the role of Hh in DU-induced nephrotoxicity was still unclear. This study was carried out to investigate the effect of Gli2, which was an important transcription effector of Hh signaling, on DU induced nephrotoxicity. To clarify it, CK19 positive tubular epithelial cells specific Gli2 conditional knockout (KO) mice model was exposed to DU, and then histopathological damage and Hh signaling pathway activation was analyzed. Moreover, HEK-293 T cells were exposed to DU with Gant61 or Gli2 overexpression, and cytotoxicity of DU as analyzed. Results showed that DU caused nephrotoxicity accompanied by activation of Hh signaling pathway. Meanwhile, genetic KO of Gli2 reduced DU-induced nephrotoxicity by normalizing biochemical indicators and reducing Hh pathway activation. Pharmacologic inhibition of Gli1/2 by Gant61 reduced DU induced cytotoxicity by inhibiting apoptosis, ROS formation and Hh pathway activation. However, overexpression of Gli2 aggravated DU-induced cytotoxicity by increasing the levels of apoptosis and ROS formation. Taken together, these results revealed that Hh signaling negatively regulated DU-inducted nephrotoxicity, and that inhibition of Gli2 might serve as a promising nephroprotective target for DU-induced kidney injury.

A European manufacturing line for monolithic U–Mo bare foil production

The nuclear research reactor Forschungs-Neutronenquelle Heinz Maier-Leibnitz (FRM II), operated by the Technical University of Munich (TUM) in Germany, provides intense thermal neutron beams for the international scientific community. The uranium fuel currently used for the compact core is an assembly of fuel plates composed of dispersed U3Si2 powder with an enrichment up to 93%, dispersed in aluminium (Al) powder and cladded with an Al alloy. Within the international efforts to minimise the usage of HEU (Highly Enriched Uranium), the FRM II aims to convert its compact core to LEU (Low Enriched Uranium), i.e., a fuel with an enrichment in 235U lower than 20%. The most promising candidate is the metallic monolithic uranium–molybdenum alloy (U–Mo) with zirconium (Zr) coating and Al-based cladding. Here, we show the first European pilot line for U–Mo bare foil manufacturing, implemented in collaboration with the European fuel manufacturer Framatome-CERCATM in Romans-sur-Isère, France. This line involves innovative manufacturing processes, including casting, laser welding, hot rolling, and laser cutting. An overview of the bare foil development with the first results is presented, including visual inspections of foils produced from the hot rolling, the laser cutting and the manufacturing tools used. These first depleted uranium (DU) bare foils are analysed to extract the best manufacturing parameters for future industrialisation. This European manufacturing process gives an alternative solution to the US development for U–Mo monolithic bare foil manufacturing. It represents the first step for European monolithic fuel manufacturing, which could push other European research reactors to use the monolithic U–Mo for their conversion.

Revealing microstructure and the associated corrosion mechanism of Al/amorphous Al2O3/Al tri-layer coating deposited on depleted uranium by magnetron sputtering

As important energy materials, uranium and its alloys have been widely used in the fields of material sciences and nuclear industrial applications. Applying metal and/or ceramic surface protective coatings can effectively retard easy corrosion of uranium with extremely high chemical activity. In principle, ideal surface protective coatings should possess (1) lowered density of elongated diffusion pathways (i.e. grain boundaries and growth defects) and (2) improved interfacial bonding to substrate by preventing corrosion medium from reacting with uranium. In this work, we have demonstrated that by magnetron-sputtering amorphous Al2O3 (a-Al2O3) interlayers within Al coatings on depleted uranium (DU), the corrosion resistance is significantly improved as indicated by corrosion potential datum DU substrate (−645 mV), DU with mono-layer Al coating (−610 mV) and DU with Al/a-Al2O3/Al tri-layer coating (−550 mV). Diffusion pathways are elongated with misalignment of columnar grain boundaries in Al coatings around a-Al2O3 interlayers. Meanwhile, density of diffusion pathways is lowered since a-Al2O3 does not contain conventional crystal defects, and can suppress accumulation and facilitate outgassing of Ar bubbles as major growth defects. The effect of coating/substrate interfacial bonding on corrosion behavior is investigated by introduction of intermixing layers between Al- and UO2-rich interfacial regions. A strategy to improve anti-corrosion stability of Al/a-Al2O3/Al tri-layer coating by optimizing degree of intermixing is proposed. The present findings may shed lights on compositional and microstructural design of anti-corrosion coatings on uranium and its alloys.

A toxicokinetic–toxicodynamic model with a transgenerational damage to explain toxicity changes over generations (in Daphnia magna exposed to depleted uranium).

We used a toxicokinetic–toxicodynamic (TKTD) model to analyze chronic effects, in Daphnia magna exposed to waterborne depleted uranium (DU) for two or three successive generations (F0, F1 and F2). Our aim was to understand how DU toxicity for growth and reproduction increased across generations. For the first time in a TKTD model, we introduced a novel transgenerational damage compartment, whose level was transmitted from parents to progeny upon egg deposition. Various exposure regimes took account of differences in exposure among generations. We used a simplified dynamic energy budget applied to toxicology (DEBtox) including two independent physiological modes of action (pMoA). The first pMoA, a reduction in assimilation linked to internal concentration, was previously confirmed by complementary analyses (direct measurements of carbon assimilation, histological observations of gut epithelium alterations). The second pMoA, an increase in costs for growth and maturation linked to transgenerational damage, was the most likely among three possible pMoA affecting both growth and reproduction. Modelling results showed that internal concentration and transgenerational damage followed strongly different kinetics across generations, suggesting that the two pMoA played very contrasting roles in long-term DU toxicity for D. magna. Internal concentration only increased between generations F0 and F1, showing no further difference between generations F1 and F2. Our model was able to correctly describe and predict DU toxicity data, in all tested generations and concentrations, and provided a mechanistic explanation for the increase in DU toxicity across generations.

Performance of Impulse Oscillometry in Identifying Restrictive Lung Defects in a Veteran Cohort.

Impulse oscillometry (IOs) is a technique used to evaluate lung function that uses sound waves imposed over tidal breathing to characterize the airways and lung parenchyma. IOs has been particularly useful in the identification of obstructive lung defects. The present analysis seeks to explore the use of IOs in the identification of restrictive lung physiology among a group of Gulf War I veterans exposed to depleted uranium (DU). A total of 36 out of a dynamic 85-veteran cohort attended in-person surveillance visits in 2019 and completed both IOs and PFTs. Performance on IOs was evaluated in a cross-sectional analysis of the group overall and in those identified as having restrictive lung defects defined by either spirometry (FEV1/FVC ≥ LLN and FVC < LLN) or lung volumes (TLC < LLN). A total of 6 individuals were identified as having restriction (4 based on spirometry alone and an additional 2 by lung volumes). When restriction was present, IOs values of both resistance and reactance were significantly more abnormal. In the assessment of lung function, IOs may be advantageous over PFTs because it is faster to perform and effort-independent. Although little is known about the utility of IOs in identifying restrictive lung physiology, our results support its use.

9 MV LINAC Photoneutron Interrogation of Uranium With Advanced Acoustically Tensioned Metastable Fluid Detectors

Abstract Active special nuclear material (SNM) photoneutron interrogation research with acoustically tensioned metastable fluid detector (ATMFD) sensor technology is discussed, which provides evidence for enabling real-time detection of SNM even when deployed under extreme 15,000 R h−1 (9 MeV endpoint) X-ray beams. Experiments to detect 3.2 kg depleted uranium (DU) are described with the use of two designs of the economical acoustically tensioned metastable fluid detector (E-ATMFD), viz., E-ATMFD.Ver.0 and E-ATMFD.Ver.1, respectively, at standoffs ranging from 0.1 m to 10 m—including with the E-ATMFD directly within the interrogating beam. Under similar conditions and with 100% photon rejection (i.e., 0 cpm with beam on, and without SNM), the E-ATMFD.Ver.1 design operating at ∼0.9 W of drive power was shown capable of ∼6× (600%) higher gain over E-ATMFD.Ver.0 operating at ∼7 W (with beam on and with SNM). The sensitivity gain rises to ∼27× (i.e., 2700%) with the E-ATMFD.Ver.1 operating at 0.99 W and a background count rate of ∼1 cpm. The E-ATMFD.Ver.1 demonstrated 100% photon blindness (0 cpm) while operating at ∼0.56 W drive power and placed directly within the beam under 15,000 R/h; including the SNM target led to a count rate of up to 50 cpm—revealing the E-ATMFD.Ver.1 is potential field capable of detecting U-based SNMs within seconds from photofission neutron signals, even when deployed directly within the intense (15,000 R/h) high energy (9 MeV endpoint X-Ray) interrogating photon beam.

Armor Piercing Projectiles Based on Depleted Uranium and the Consequences of Their Use for the Environment and People

The intention of the collective West to supply the armed forces of Ukraine with armor-piercing shells with cores (penetrators) made of depleted uranium (DU), is changing the situation in the zone of special military operation (SVO). A new damaging factor is introduced into combat operations – uranium-238 (238U), one of the longest-lived natural radioactive isotopes of uranium. The purpose of the review is to identify the signs and consequences of the use of armor-piercing projectiles based on depleted uranium. Materials and research methods. The sources available through the PubMed, Google Scholar and Russian Electronic Library databases were analyzed. Research results. NATO uses DU in 20-, 25-, 30-, 105-, 120- and 140-mm caliber projectiles. The cores are made from recycled DU, which is a waste from the production of nuclear weapons. Due to man-made isotopes, it is more radioactive than DU from natural uranium. When such a projectile hits an armored object, a large amount of respirable radioactive and toxic dust of black uranium oxides, small fragments and fragments of the penetrator, remaining in the armored vehicles and around it, is formed. One 120 mm projectile produces approximately 950 g of black dust. Almost 99 % of the internal dose received by the military will come from alpha particles, the most dangerous to health. Projectiles that miss their targets sink deep into the soil, their penetrators corrode for decades, releasing soluble uranium compounds into underground water sources. In areas where DU shells were used, mass diseases of «unexplained etiology» are observed among military personnel and civilians, reducing their life expectancy and fertility. Discussion of results and conclusions. The first signs of the use of shells with DU, which can be installed on the battlefield: round holes in the armor of tanks and the presence of solid black dust around them and in the tank itself. In case of fires in the warehouses of such shells, due to other oxidation conditions, crumbling yellow dust is formed. When examining it, it is necessary to pay attention to the presence of elevated concentrations of 236U. The fact that a soldier was hit by DU can be confirmed by the presence of uranium in his urine. The use of DU shells on the territory of the Russian Federation, in terms of its consequences for people and nature, is the use of radiological weapons, a disguised form of nuclear warfare. And it must be treated accordingly.

Characterization of Uranyl (UO22+) Ion Binding to Amyloid Beta (Aβ) Peptides: Effects on Aβ Structure and Aggregation.

Uranium (U) is naturally present in ambient air, water, and soil, and depleted uranium (DU) is released into the environment via industrial and military activities. While the radiological damage from U is rather well understood, less is known about the chemical damage mechanisms, which dominate in DU. Heavy metal exposure is associated with numerous health conditions, including Alzheimer's disease (AD), the most prevalent age-related cause of dementia. The pathological hallmark of AD is the deposition of amyloid plaques, consisting mainly of amyloid-β (Aβ) peptides aggregated into amyloid fibrils in the brain. However, the toxic species in AD are likely oligomeric Aβ aggregates. Exposure to heavy metals such as Cd, Hg, Mn, and Pb is known to increase Aβ production, and these metals bind to Aβ peptides and modulate their aggregation. The possible effects of U in AD pathology have been sparsely studied. Here, we use biophysical techniques to study in vitro interactions between Aβ peptides and uranyl ions, UO22+, of DU. We show for the first time that uranyl ions bind to Aβ peptides with affinities in the micromolar range, induce structural changes in Aβ monomers and oligomers, and inhibit Aβ fibrillization. This suggests a possible link between AD and U exposure, which could be further explored by cell, animal, and epidemiological studies. General toxic mechanisms of uranyl ions could be modulation of protein folding, misfolding, and aggregation.

A thermal natural uranium breeder reactor for large and small applications with passive safeguard designs

This research explored a novel reactor design capable of hyper-breeding, potentially greater than any design previously evaluated (fast or thermal). Reactor breeding estimates at power were predicted to exceed 1.55 (Hayes, 2006) using only natural uranium making it of substantial interest for obtaining a high burnup fuel cycle. It has also been shown capable of starting with only natural uranium (NU) fuel making it highly attractive from a non-proliferation or small modular reactor (SMR)/microreactor perspective. The breeding capability also allows for partial refuelling with depleted uranium (DU) with a new core burnup capability >3 GW yr (Hayes, 2007, 2008). Previous scoping calculations demonstrated great promise having only evaluated metallic, unclad slab fuel geometries without considerations for material performance after irradiation or the thermal hydraulics of such a system. This work reviews the technical basis for such a neutron economy where reactor physics considerations demonstrate how such a heterogenous configuration enables apparently drastic changes in reactor performance. These changes subsequently create the potential for application in SMR/microreactor technology such that high enriched low assay uranium (HALEU), and its associated inherent limitations, may not be necessary. In addition, novel non-proliferation technology is also considered which could further mitigate closed fuel cycle models for this reactor concept by providing passive monitoring capabilities such that the design incorporates multiple layers of safety and security. Overall, the technology here argues for a novel set of technologies making for passively non-proliferation safe nuclear reactors.

Depleted uranium induces thyroid damage through activation of ER stress via the thrombospondin 1-PERK pathway

Depleted uranium (DU) can cause damage to the body, but its effects on the thyroid are unclear. The purpose of this study was to investigate the DU-induced thyroid damage and its potential mechanism in order to find new targets for detoxification after DU poisoning. A model of acute exposure to DU was constructed in rats. It was observed that DU accumulated in the thyroid, induced thyroid structure disorder and cell apoptosis, and decreased the serum T4 and FT4 levels. Gene screening showed that thrombospondin 1 (TSP-1) was a sensitive gene of DU, and the expression of TSP-1 decreased with the increase of DU exposure dose and time. TSP-1 knockout mice exposed to DU had more severe thyroid damage and lower serum FT4 and T4 levels than wild-type mice. Inhibiting the expression of TSP-1 in FRTL-5 cells aggravated DU-induced apoptosis, while exogenous TSP-1 protein alleviated the decreased viability in FRTL-5 cells caused by DU. It was suggested that DU may caused thyroid damage by down-regulating TSP-1. It was also found that DU increased the expressions of PERK, CHOP, and Caspase-3, and 4-Phenylbutyric (4-PBA) alleviated the DU-induced FRTL-5 cell viability decline and the decrease levels of rat serum FT4 and T4 caused by DU. After DU exposure, the PERK expression was further up-regulated in TSP-1 knockout mice, and the increased expression of PERK was alleviated in TSP-1 over-expressed cells, as well as the increased expression of CHOP and Caspase-3. Further verification showed that inhibition of PERK expression could reduce the DU-induced increased expression of CHOP and Caspase-3. These findings shed light on the mechanism that DU may activate ER stress via the TSP 1-PERK pathway, thereby leading to thyroid damage, and suggest that TSP-1 may be a potential therapeutic target for DU-induced thyroid damage.