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NpPd2Al3 crystallizes in the hexagonal P6/mmm space group. The structure is three-dimensional. Np is bonded in a distorted hexagonal planar geometry to six equivalent Pd atoms. All Np–Pd bond lengths are 3.16 Å. Pd is bonded in a 9-coordinate geometry to three equivalent Np and six equivalent Al atoms. All Pd–Al bond lengths are 2.62 Å. Al is bonded in a 12-coordinate geometry to four equivalent Pd atoms.
NpTm3 is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Np is bonded to twelve equivalent Tm atoms to form NpTm12 cuboctahedra that share corners with twelve equivalent NpTm12 cuboctahedra, edges with twenty-four equivalent TmTm8Np4 cuboctahedra, faces with six equivalent NpTm12 cuboctahedra, and faces with twelve equivalent TmTm8Np4 cuboctahedra. All Np–Tm bond lengths are 3.45 Å. Tm is bonded to four equivalent Np and eight equivalent Tm atoms to form TmTm8Np4 cuboctahedra that share corners with twelve equivalent TmTm8Np4 cuboctahedra, edges with eight equivalent NpTm12 cuboctahedra, edges with sixteen equivalent TmTm8Np4 cuboctahedra, faces with four equivalent NpTm12 cuboctahedra, and faces with fourteen equivalent TmTm8Np4 cuboctahedra. All Tm–Tm bond lengths are 3.45 Å.
NpNd3 is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Np is bonded to twelve equivalent Nd atoms to form NpNd12 cuboctahedra that share corners with six equivalent NpNd12 cuboctahedra, corners with twelve equivalent NdNd8Np4 cuboctahedra, edges with eighteen equivalent NdNd8Np4 cuboctahedra, faces with eight equivalent NpNd12 cuboctahedra, and faces with twelve equivalent NdNd8Np4 cuboctahedra. There are six shorter (3.63 Å) and six longer (3.67 Å) Np–Nd bond lengths. Nd is bonded to four equivalent Np and eight equivalent Nd atoms to form NdNd8Np4 cuboctahedra that share corners with four equivalent NpNd12 cuboctahedra, corners with fourteen equivalent NdNd8Np4 cuboctahedra, edges with six equivalent NpNd12 cuboctahedra, edges with twelve equivalent NdNd8Np4 cuboctahedra, faces with four equivalent NpNd12 cuboctahedra, and faces with sixteen equivalent NdNd8Np4 cuboctahedra. There are a spread of Nd–Nd bond distances ranging from 3.62–3.73 Å.
NpHo3 is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Np is bonded to twelve equivalent Ho atoms to form NpHo12 cuboctahedra that share corners with six equivalent NpHo12 cuboctahedra, corners with twelve equivalent HoHo8Np4 cuboctahedra, edges with eighteen equivalent HoHo8Np4 cuboctahedra, faces with eight equivalent NpHo12 cuboctahedra, and faces with twelve equivalent HoHo8Np4 cuboctahedra. There are six shorter (3.45 Å) and six longer (3.51 Å) Np–Ho bond lengths. Ho is bonded to four equivalent Np and eight equivalent Ho atoms to form HoHo8Np4 cuboctahedra that share corners with four equivalent NpHo12 cuboctahedra, corners with fourteen equivalent HoHo8Np4 cuboctahedra, edges with six equivalent NpHo12 cuboctahedra, edges with twelve equivalent HoHo8Np4 cuboctahedra, faces with four equivalent NpHo12 cuboctahedra, and faces with sixteen equivalent HoHo8Np4 cuboctahedra. There are a spread of Ho–Ho bond distances ranging from 3.46–3.55 Å.
LiNpRu2 is Heusler structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Li is bonded in a body-centered cubic geometry to eight equivalent Ru atoms. All Li–Ru bond lengths are 2.74 Å. Np is bonded in a body-centered cubic geometry to eight equivalent Ru atoms. All Np–Ru bond lengths are 2.74 Å. Ru is bonded in a body-centered cubic geometry to four equivalent Li and four equivalent Np atoms.
NpScRu2 is Heusler structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Np is bonded in a body-centered cubic geometry to eight equivalent Ru atoms. All Np–Ru bond lengths are 2.84 Å. Sc is bonded in a body-centered cubic geometry to eight equivalent Ru atoms. All Sc–Ru bond lengths are 2.84 Å. Ru is bonded in a body-centered cubic geometry to four equivalent Np and four equivalent Sc atoms.
LiNpRh2 is Heusler structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Li is bonded in a body-centered cubic geometry to eight equivalent Rh atoms. All Li–Rh bond lengths are 2.78 Å. Np is bonded in a body-centered cubic geometry to eight equivalent Rh atoms. All Np–Rh bond lengths are 2.78 Å. Rh is bonded in a body-centered cubic geometry to four equivalent Li and four equivalent Np atoms.
Np2Te3 crystallizes in the tetragonal I-42d space group. The structure is three-dimensional. there are three inequivalent Np3+ sites. In the first Np3+ site, Np3+ is bonded to eight Te2- atoms to form a mixture of distorted face, edge, and corner-sharing NpTe8 hexagonal bipyramids. There are a spread of Np–Te bond distances ranging from 3.12–3.31 Å. In the second Np3+ site, Np3+ is bonded to eight Te2- atoms to form a mixture of distorted face, edge, and corner-sharing NpTe8 hexagonal bipyramids. There are a spread of Np–Te bond distances ranging from 3.13–3.33 Å. In the third Np3+ site, Np3+ is bonded to eight Te2- atoms to form a mixture of distorted face, edge, and corner-sharing NpTe8 hexagonal bipyramids. There are a spread of Np–Te bond distances ranging from 3.13–3.32 Å. There are three inequivalent Te2- sites. In the first Te2- site, Te2- is bonded in a 6-coordinate geometry to six Np3+ atoms. In the second Te2- site, Te2- is bonded to five Np3+ atoms to form a mixture of distorted face, edge, and corner-sharing TeNp5 square pyramids. In the third Te2- site, Te2- is bonded to five Np3+ atoms to form a mixture of distorted face, edge, and corner-sharing TeNp5 square pyramids.
A MS Excel tool was created to help track Pu-238 production, Np-237 feedstock use, estimate production scenarios, and coordinate planning for shipments. As-run estimates were used as a basis for beginning and end of life isotopic concentrations. Multiple target types were created to demonstrate a proof of concept while actual results were not yet available The initial goals of this production tool were: • Track unirradiated, currently irradiated, and irradiated targets at the Advanced Test Reactor (ATR) • Estimate production yields from irradiated targets in various positions for each cycle • Provide past, current, and future year quantities of Np-237 and Pu-238 at ATR, amounts shipped to ATR and amounts shipped from ATR • Estimate production from current and future target designs based on data from numerical modeling (values will be provided by Idaho National Laboratory (INL)) • After proof of principle, additional work is planned that will further enhance the tool with: o Incorporate the High Flux Isotope Reactor (HFIR) reactor at Oak Ridge National Laboratory (ORNL) for irradiation o Incorporate irradiations and target shipments from ORNL to INL and back to track Np-237 transfers across the Department of Energy (DOE) Complex
Abstract Nanoparticle (NP) sintering is a major cause of the deactivation of supported catalysts. Raspberry‐colloid‐templated (RCT) catalysts are an emerging class of materials that show an unprecedented level of sinter‐resistance and exhibit high catalytic activity. Here a comprehensive study of the origin of NP stability and accessibility in RCT catalysts using theoretical modeling, 3D electron microscopy, and epitaxial overgrowth is reported. The approach is showcased for silica‐based RCT catalysts containing dilute Pd‐in‐Au NPs previously used in hydrogenation and oxidation catalysis. Modeling of the contact line of the silica precursor infiltrating into the assembled raspberry colloids suggests that a large part of the particles must be embedded into silica, which is confirmed by quantitative visualization of >200 individual NPs by dual‐axis electron tomography. The RCT catalysts have a unique structure in which all NPs reside at the pore wall but have >50% of their surface embedded in the matrix, giving rise to the strongly enhanced thermal and mechanical stability. Importantly, epitaxial overgrowth of Ag on the supported NPs reveals that not only the NP surface exposed to the pore but the embedded interface as well remained chemically accessible. This mechanistic understanding provides valuable guidance in the design of stable catalytic materials.
Abstract Understanding the chemistry of the inert actinide oxo bond in actinyl ions AnO 2 2+ is important for controlling actinide behavior in the environment, during separations, and in nuclear waste (An=U, Np, Pu). The thioether calixarene TC4A (4‐ tert ‐butyltetrathiacalix[4]arene) binds equatorially to the actinyl cation forming a conical pocket that differentiates the two trans‐ oxo groups. The ‘ate’ complexes, [A] 2 [UO 2 (TC4A)] (A=[Li(DME) 2 ], HNEt 3 ) and [HNEt 3 ] 2 [AnO 2 (TC4A)] (An=U, Np, Pu), enable selective oxo chemistry. Silylation of the U VI oxo groups by bis(trimethylsilyl)pyrazine occurs first at only the unencapsulated exo oxo and only one silylation is needed to enable migration of the endo oxo out of the cone, whereupon a second silylation affords the stable U IV cis‐ bis(siloxide) [A] 2 [U(OSiMe 3 ) 2 (TC4A)]. Calculations confirm that only one silylation event is needed to initiate oxo rearrangement, and that the putative cis dioxo isomer of [UO 2 (TC4A)] 2− would be stable if it could be accessed synthetically, at only 23 kcal.mol −1 in energy above the classical trans dioxo. Calculations for the transuranic cis [AnO 2 (TC4A)] 2− (An=Np, Pu) are at higher energies, 30–35 kcal.mol −1 , retaining the U complexes as the more obvious target for a cis ‐dioxo actinyl ion. The aryloxide (OAr) groups of the macrocycle are essential in stabilizing this as‐yet unseen uranyl geometry as further bonding in the TC4A U‐O Ar groups stabilizes the U=O ‘yl’ bonds, explaining the stability of the putative cis [UO 2 (TC4A)] 2− in this ligand framework.
Understanding the chemistry of the inert actinide oxo bond in actinyl ions AnO2 2+ is important for controlling actinide behavior in the environment, during separations, and in nuclear waste (An=U, Np, Pu). The thioether calixarene TC4A (4-tert-butyltetrathiacalix[4]arene) binds equatorially to the actinyl cation forming a conical pocket that differentiates the two trans-oxo groups. The 'ate' complexes, [A]2[UO2(TC4A)] (A=[Li(DME)2], HNEt3) and [HNEt3]2[AnO2(TC4A)] (An=U, Np, Pu), enable selective oxo chemistry. Silylation of the UVI oxo groups by bis(trimethylsilyl)pyrazine occurs first at only the unencapsulated exo oxo and only one silylation is needed to enable migration of the endo oxo out of the cone, whereupon a second silylation affords the stable UIV cis-bis(siloxide) [A]2[U(OSiMe3)2(TC4A)]. Calculations confirm that only one silylation event is needed to initiate oxo rearrangement, and that the putative cis dioxo isomer of [UO2(TC4A)]2- would be stable if it could be accessed synthetically, at only 23 kcal.mol-1 in energy above the classical trans dioxo. Calculations for the transuranic cis[AnO2(TC4A)]2- (An=Np, Pu) are at higher energies, 30-35 kcal.mol-1, retaining the U complexes as the more obvious target for a cis-dioxo actinyl ion. The aryloxide (OAr) groups of the macrocycle are essential in stabilizing this as-yet unseen uranyl geometry as further bonding in the TC4A U-OAr groups stabilizes the U=O 'yl' bonds, explaining the stability of the putative cis[UO2(TC4A)]2- in this ligand framework.
Abstract The emergence of drug‐resistant pathogens necessitates the development of new countermeasures. In this regard, the introduction of probiotics to directly attack or competitively exclude pathogens presents a useful strategy. Application of this approach requires an understanding of how a probiotic and its target pathogen interact. A key means of probiotic‐pathogen interaction involves the production of small molecules called natural products (NPs). Here, we report the use of whole‐cell matrix‐assisted laser desorption/ionization time‐of‐flight (MALDI‐ToF) mass spectrometry to characterize NP production by candidate probiotics (mouse airway microbiome isolates) when co‐cultured with the respiratory pathogen Burkholderia . We found that a Bacillus velezensis strain inhibits growth of and elicits NP production by Burkholderia thailandensis . Dereplication of known NPs detected in the metabolome of this B. velezensis strain suggests that a previously unannotated bioactive compound is involved. Thus, we present the use of whole‐cell MALDI as a broadly applicable method for screening the NP composition of microbial co‐cultures; this can be combined with other ‐omics methods to characterize probiotic‐pathogen and other microbe‐microbe interactions.
We report two Np(III) halides, NpI 3 (THF) 4 and NpBr 3 (THF) 4 , have been prepared and isolated in high yields as described in this work. Starting with neptunia (NpO 2 ), NpCl 4 (DME) 2 was first generated in an updated, higher yielding synthesis than what was previously reported by using HCl/HF. This material was then reduced with KC 8 , followed by subsequent ligand exchange, to generate NpBr 3 (THF) 4 and NpI 3 -(THF) 4 . Full characterization by single-crystal X-ray crystallography, 1 H NMR spectroscopy and electronic absorption spectroscopy confirmed the molecular formulas and oxidation states. These trivalent materials are straightforward to synthesize and can be used as starting materials for non-aqueous Np(III) chemistry, obviating the need for rare and restricted Np metal and elemental halogens.
The non-enzymatic electrochemical sensing of hydrogen peroxide (H 2 O 2 ) is described. This study utilized a 3D bicontinuous nanoporous platinum-gold alloy-based sensor (NP-Pt(Au) electrode), which has a morphology that resembles a molecular sieve. SEM and CV were used to evaluate the morphological and electrochemical characteristics of the NP-Pt(Au) electrodes. The cathodic voltammetric response of H 2 O 2 was enhanced at the NP-Pt(Au) as compared to planar Pt electrodes. Further, the nanoporous electrode was able to maintain the H 2 O 2 voltammetric profile even in the presence of the biofouling agent, serum albumin. Its application as a non-enzymatic sensor for the amperometric measurement of H 2 O 2 was explored.
By improving the delivery and tumor retention of chemotherapeutics, nanomedicines hold potential for cancer treatment. The usefulness of nanoparticle (NP)-encapsulated analgesics for the cancer pain treatment is comparatively unexplored. We investigated whether NPs encapsulating olcegepant (OCP), an antagonist of the calcitonin receptor-like receptor (CLR) for the calcitonin gene-related peptide (CGRP), effectively relieved oral cancer pain in mice. Because persistent endosomal CLR signaling in Schwann cells mediates craniofacial pain, we reasoned that the predisposition of NPs to accumulate in endosomes could be leveraged to effectively relieve oral cancer pain. By expressing biosensors for activated CLR, Gα proteins and β-arrestins in HEK293T and Schwann cells, we found that CGRP activates CLR signaling first at the plasma membrane and then in early, late and recycling endosomes and the cis- and trans-Golgi apparatus. We synthesized biocompatible NPs encapsulating OCP and fluorophores by integrating hydrophobic ion pairing nanoformulation with Flash NanoPrecipitation. NPs slowly released OCP and accumulated in early endosomes, leading to sustained inhibition of endosomal CLR signaling in HEK293T and Schwann cells. Oral cancers were established in mice, which led to heightened pain-like responses. After intra-tumoral injection, NPs were retained in tumors for at least one week. OCP-loaded NPs almost completely reversed allodynia and hyperalgesia for a prolonged period, whereas unencapsulated OCP had small and transient effects. The NP accumulation in endosomal sites of pain signaling, the sustained release of antagonist, and the retention of NPs in tumors explain their beneficial actions. Thus, NP-encapsulation holds promise for the relief of painful cancers that are inadequately treated by opioids.
The study of gradient nanoglasses (GNGs) has gained attention due to their unique mechanical properties and potential applications in advanced materials. This study employs molecular dynamics simulations to synthesize a GNG using Cu-Zr metallic glass nanoparticles (NPs) sized from 3 to 15 nm. The NPs were produced by melting and quenching metallic clusters at a relatively slow quench rate of 10 9 K/s. The synthesis of GNG is elucidated along with the characterization of its heterogeneous metallic glass nanostructure. A seamless GNG structure is formed through cold compression of Cu 64 Zr 36 amorphous NPs of varying sizes. The influence of NP size on the GNG structure is investigated, utilizing deeply relaxed NPs, which exhibit a characteristic Cu segregation pattern on their surfaces. The results highlight an increase in structural heterogeneity due to heterogeneous mass transport and the development of local composition and density variations caused by Cu segregation at glass-glass interfaces (GGIs). A reduction in NP size is correlated with decreased Cu atomic displacements and local density at GGIs, suggesting that larger NPs may produce stronger GGIs. This research presents a novel methodology for synthesizing heterogeneous metallic glasses, demonstrating the capacity to control and customize nanostructure heterogeneity through the manipulation of NP sizes and cooling rates. Furthermore, these findings enhance our understanding of structural evolution during nanoglass synthesis and lay the foundation for further exploration in nanomaterial synthesis and characterization.
The three-dimensional grain-averaged response of solid bar samples under non-proportional (NP) elastoplastic axial-torsional loading was investigated using in situ high energy diffraction microscopy (HEDM) and companion crystal plasticity finite element (CPFE) modeling. Important stress metrics including applied shear (σ θZ ) and axial (σ ZZ ) stress tensor components, stress and stress deviator tensor invariants (I 1 , J 2 , and J 3 ), von Mises equivalent stress (σ$^{grain}_{VM}$), maximum resolved shear stress (mRSS), stress triaxiality (η), and lode angle parameter ($\barθ$) values were tracked for ~300 grains under two different loading conditions: (1) Torsion-dominated loading (low NP) and (2) Tension-torsion loading (high NP) in equiatomic NiCoCr, a representative multicomponent face-centered cubic (FCC) superalloy. Overall, significant stress localizations existed within both samples as evidenced by the radial dependence of grain-resolved σ θZ , σ$^{grain}_{VM}$, and J 2 ; by comparison, I 1 , J 3 , η, and $\barθ$ metrics did not show discernible trends within the volume. These stress localizations reveal a complex interplay between axial and shear stress components (e.g., stress coupling) resulting in grain yielding near the sample surface largely driven by shear stress, whereas internal grain yielding was largely accommodated by axial stress. Grain-resolved stress localization trends were described well by the CPFE model, although some discrepancies in magnitude occurred, particularly for volumetric stress metrics (I 1 and η) due to initial type II residual stress distributions. The superposition of initial residual stress states onto CPFE grain-resolved data significantly improved model accuracy for η. This suggests that residual stresses more strongly influence the simulation of volumetric rather than deviatoric (yield) stress metrics.