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DOE OSTI2020

Materials Data on Ba10Ca5Cu10Hg5O31 by Materials Project

Ba10Ca5Cu10Hg5O31 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are five inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Ba–O bond distances ranging from 2.69–2.92 Å. In the second Ba2+ site, Ba2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ba–O bond distances ranging from 2.78–2.87 Å. In the third Ba2+ site, Ba2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ba–O bond distances ranging from 2.77–2.87 Å. In the fourth Ba2+ site, Ba2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ba–O bond distances ranging from 2.77–2.87 Å. In the fifth Ba2+ site, Ba2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ba–O bond distances ranging from 2.78–2.87 Å. There are three inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.48–2.51 Å. In the second Ca2+ site, Ca2+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are two shorter (2.47 Å) and six longer (2.49 Å) Ca–O bond lengths. In the third Ca2+ site, Ca2+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.47–2.49 Å. There are five inequivalent Cu+2.20+ sites. In the first Cu+2.20+ site, Cu+2.20+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There are a spread of Cu–O bond distances ranging from 1.92–1.94 Å. In the second Cu+2.20+ site, Cu+2.20+ is bonded in a square co-planar geometry to four O2- atoms. There are a spread of Cu–O bond distances ranging from 1.92–1.94 Å. In the third Cu+2.20+ site, Cu+2.20+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There are a spread of Cu–O bond distances ranging from 1.92–1.94 Å. In the fourth Cu+2.20+ site, Cu+2.20+ is bonded in a square co-planar geometry to four O2- atoms. There are a spread of Cu–O bond distances ranging from 1.92–1.94 Å. In the fifth Cu+2.20+ site, Cu+2.20+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. All Cu–O bond lengths are 1.93 Å. There are two inequivalent Hg2+ sites. In the first Hg2+ site, Hg2+ is bonded in a T-shaped geometry to three O2- atoms. There are two shorter (2.04 Å) and one longer (2.64 Å) Hg–O bond lengths. In the second Hg2+ site, Hg2+ is bonded in a linear geometry to two equivalent O2- atoms. Both Hg–O bond lengths are 2.00 Å. There are sixteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a 5-coordinate geometry to four Ba2+ and one Hg2+ atom. The O–Hg bond length is 2.04 Å. In the second O2- site, O2- is bonded in a 5-coordinate geometry to four Ba2+ and one Hg2+ atom. In the third O2- site, O2- is bonded in a 5-coordinate geometry to four Ba2+ and one Hg2+ atom. In the fourth O2- site, O2- is bonded in a 5-coordinate geometry to four Ba2+ and one Hg2+ atom. The O–Hg bond length is 2.04 Å. In the fifth O2- site, O2- is bonded in a 1-coordinate geometry to four Ba2+ and one Hg2+ atom. In the sixth O2- site, O2- is bonded in a 6-coordinate geometry to two Ba2+, two Ca2+, and two Cu+2.20+ atoms. In the seventh O2- site, O2- is bonded in a 6-coordinate geometry to two Ba2+, two Ca2+, and two Cu+2.20+ atoms. In the eighth O2- site, O2- is bonded to two Ba2+, two Ca2+, and two Cu+2.20+ atoms to form a mixture of distorted corner, edge, and face-sharing OBa2Ca2Cu2 octahedra. The corner-sharing octahedra tilt angles range from 0–66°. In the ninth O2- site, O2- is bonded to two Ba2+, two equivalent Ca2+, and two Cu+2.20+ atoms to form a mixture of distorted corner, edge, and face-sharing OBa2Ca2Cu2 octahedra. The corner-sharing octahedra tilt angles range from 0–67°. In the tenth O2- site, O2- is bonded to two Ba2+, two Ca2+, and two Cu+2.20+ atoms to form a mixture of distorted corner, edge, and face-sharing OBa2Ca2Cu2 octahedra. The corner-sharing octahedra tilt angles range from 0–66°. In the eleventh O2- site, O2- is bonded in a 6-coordinate geometry to two Ba2+, two equivalent Ca2+, and two Cu+2.20+ atoms. In the twelfth O2- site, O2- is bonded to two Ba2+, two Ca2+, and two Cu+2.20+ atoms to form a mixture of distorted corner, edge, and face-sharing OBa2Ca2Cu2 octahedra. The corner-sharing octahedra tilt angles range from 0–66°. In the thirteenth O2- site, O2- is bonded in a 6-coordinate geometry to two Ba2+, two Ca2+, and two Cu+2.20+ atoms. In the fourteenth O2- site, O2- is bonded to two Ba2+, two Ca2+, and two Cu+2.20+ atoms to form a mixture of distorted corner, edge, and face-sharing OBa2Ca2Cu2 octahedra. The corner-sharing octahedra tilt angles range from 0–66°. In the fifteenth O2- site, O2- is bonded to two Ba2+, two Ca2+, and two Cu+2.20+ atoms to form a mixture of distorted corner, edge, and face-sharing OBa2Ca2Cu2 octahedra. The corner-sharing octahedra tilt angles range from 0–67°. In the sixteenth O2- site, O2- is bonded in an octahedral geometry to two equivalent Ba2+ and four equivalent Hg2+ atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on ZnHg4Te5 by Materials Project

Hg4ZnTe5 is Lavarevi\'{c}ite-like structured and crystallizes in the trigonal R3m space group. The structure is three-dimensional. there are four inequivalent Hg2+ sites. In the first Hg2+ site, Hg2+ is bonded to four Te2- atoms to form HgTe4 tetrahedra that share corners with three equivalent ZnTe4 tetrahedra and corners with nine HgTe4 tetrahedra. There are one shorter (2.87 Å) and three longer (2.88 Å) Hg–Te bond lengths. In the second Hg2+ site, Hg2+ is bonded to four Te2- atoms to form corner-sharing HgTe4 tetrahedra. There are one shorter (2.85 Å) and three longer (2.87 Å) Hg–Te bond lengths. In the third Hg2+ site, Hg2+ is bonded to four Te2- atoms to form corner-sharing HgTe4 tetrahedra. All Hg–Te bond lengths are 2.86 Å. In the fourth Hg2+ site, Hg2+ is bonded to four Te2- atoms to form HgTe4 tetrahedra that share corners with three equivalent ZnTe4 tetrahedra and corners with nine HgTe4 tetrahedra. There are three shorter (2.88 Å) and one longer (2.89 Å) Hg–Te bond lengths. Zn2+ is bonded to four Te2- atoms to form ZnTe4 tetrahedra that share corners with six HgTe4 tetrahedra and corners with six equivalent ZnTe4 tetrahedra. There are one shorter (2.70 Å) and three longer (2.80 Å) Zn–Te bond lengths. There are five inequivalent Te2- sites. In the first Te2- site, Te2- is bonded to four Hg2+ atoms to form corner-sharing TeHg4 tetrahedra. In the second Te2- site, Te2- is bonded to four Hg2+ atoms to form corner-sharing TeHg4 tetrahedra. In the third Te2- site, Te2- is bonded to four Hg2+ atoms to form corner-sharing TeHg4 tetrahedra. In the fourth Te2- site, Te2- is bonded to one Hg2+ and three equivalent Zn2+ atoms to form corner-sharing TeZn3Hg tetrahedra. In the fifth Te2- site, Te2- is bonded to three equivalent Hg2+ and one Zn2+ atom to form corner-sharing TeZnHg3 tetrahedra.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on TlHg6Se4Br5 by Materials Project

Hg6TlSe4Br5 crystallizes in the tetragonal I4/m space group. The structure is three-dimensional. there are two inequivalent Hg2+ sites. In the first Hg2+ site, Hg2+ is bonded to two equivalent Se2- and four Br1- atoms to form a mixture of distorted edge, face, and corner-sharing HgSe2Br4 octahedra. The corner-sharing octahedra tilt angles range from 0–67°. There are one shorter (2.56 Å) and one longer (2.57 Å) Hg–Se bond lengths. There are a spread of Hg–Br bond distances ranging from 3.16–3.60 Å. In the second Hg2+ site, Hg2+ is bonded in a 4-coordinate geometry to two equivalent Se2- and two Br1- atoms. Both Hg–Se bond lengths are 2.57 Å. There are one shorter (2.88 Å) and one longer (3.22 Å) Hg–Br bond lengths. Tl1+ is bonded in a body-centered cubic geometry to eight Br1- atoms. There are four shorter (3.55 Å) and four longer (3.74 Å) Tl–Br bond lengths. Se2- is bonded in a 3-coordinate geometry to three Hg2+ atoms. There are four inequivalent Br1- sites. In the first Br1- site, Br1- is bonded in a body-centered cubic geometry to eight equivalent Hg2+ atoms. In the second Br1- site, Br1- is bonded in a body-centered cubic geometry to eight equivalent Hg2+ atoms. In the third Br1- site, Br1- is bonded in a 5-coordinate geometry to three Hg2+ and two equivalent Tl1+ atoms. In the fourth Br1- site, Br1- is bonded in a 5-coordinate geometry to three Hg2+ and two equivalent Tl1+ atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Hg3Bi2(SCl4)2 by Materials Project

Hg3Bi2(SCl4)2 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are two inequivalent Hg2+ sites. In the first Hg2+ site, Hg2+ is bonded to two equivalent S2- and four Cl1- atoms to form edge-sharing HgS2Cl4 octahedra. Both Hg–S bond lengths are 2.45 Å. There are two shorter (3.06 Å) and two longer (3.17 Å) Hg–Cl bond lengths. In the second Hg2+ site, Hg2+ is bonded to two equivalent S2- and four equivalent Cl1- atoms to form distorted edge-sharing HgS2Cl4 octahedra. Both Hg–S bond lengths are 2.43 Å. All Hg–Cl bond lengths are 3.32 Å. Bi3+ is bonded in a 7-coordinate geometry to seven Cl1- atoms. There are a spread of Bi–Cl bond distances ranging from 2.63–3.23 Å. S2- is bonded in a distorted trigonal non-coplanar geometry to three Hg2+ atoms. There are three inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a distorted water-like geometry to two equivalent Bi3+ atoms. In the second Cl1- site, Cl1- is bonded in a 4-coordinate geometry to two Hg2+ and two equivalent Bi3+ atoms. In the third Cl1- site, Cl1- is bonded in a 3-coordinate geometry to two equivalent Hg2+ and one Bi3+ atom.

36 MATERIALS SCIENCE↗

DOE OSTI2022

Mercury and Radiocesium Accumulation and Associations With Sublethal Endpoints in the Florida Green Watersnake ( Nerodia floridana )

Mercury (Hg) and radiocesium ( 137 Cs) are well-known environmental contaminants with the potential to impact the health of humans and wildlife. Snakes have several characteristics conducive to studying environmental contamination but have rarely been included in the monitoring of polluted sites. We investigated the bioaccumulation of Hg and 137 Cs and associations with sublethal effects (standard metabolic rate [SMR] and hemoparasite infections) in Florida green watersnakes (Nerodia floridana). We captured 78 snakes from three former nuclear cooling reservoirs on the US Department of Energy's Savannah River Site in South Carolina (USA). For captured snakes, we (1) determined whole-body 137 Cs, (2) quantified total Hg (THg) using snake tail clips, (3) conducted hemoparasite counts, and (4) measured the SMR. We used multiple regression models to determine associations among snake body size, capture location, sex, tail THg, whole-body 137 Cs, Hepatozoon spp. prevalence and parasitemia, and SMR. Average whole-body 137 Cs (0.23 ± 0.08 Becquerels [Bq]/g; range: 0.00–1.02 Bq/g) was correlated with snake body size and differed significantly by capture site (Pond B: 0.67 ± 0.05 Bq/g; Par Pond: 0.10 ± 0.02 Bq/g; Pond 2: 0.03 ± 0.02 Bq/g). Tail THg (0.33 ± 0.03 mg/kg dry wt; range: 0.16–2.10 mg/kg) was significantly correlated with snake body size but did not differ by capture site. We found no clear relationship between SMR and contaminant burdens. However, models indicated that the prevalence of Hepatozoon spp. in snakes was inversely related to increasing whole-body 137 Cs burdens. Our results indicate the bioaccumulation of Hg and 137 Cs in N. floridana and further demonstrate the utility of aquatic snakes as bioindicators. Furthermore, our results also suggest a decrease in Hepatozoon spp. prevalence related to increased burdens of 137 Cs. Although the results are intriguing, further research is needed to understand the dynamics between 137 Cs and Hepatozoon spp. infections in semiaquatic snakes.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2022

Bioaccumulation of Mercury and Radiocesium in Waterfowl Introduced to a Site with Legacy Contamination

Despite the propensity of waterfowl species to readily accumulate anthropogenic contaminants within polluted environments, few studies have examined bioaccumulation rates over time when entering such a contaminated site. We examined mercury (Hg) and radiocesium ( 137 Cs) bioaccumulation over time in two waterfowl species released into a wetland system containing legacy contamination on the US Department of Energy's Savannah River Site in South Carolina. Released birds were collected at select time intervals over an exposure period of 94 days. We quantified total Hg concentrations in blood, muscle, and liver tissues, and 137 Cs activity in whole-body and muscle tissues. The relationship between the contaminant burdens of different body tissue types was examined over time. Likely a result of microhabitat selection, mallards in our study readily accumulated both Hg and 137 Cs at consistent rates over time within our study system, while ring-neck ducks did not. The findings demonstrated that whole blood can be used as a robust, nondestructive sampling alternative to estimate Hg burdens within muscle and liver, and whole-body 137 Cs activity is a good predictor of muscle burdens. Understanding such bioaccumulation information in waterfowl is useful for the assessment of the potential health risk in wildlife, as well as being important for human risk assessment toward the consumption of popular game species. Environ Toxicol Chem 2022;41:2479–2487. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2025

Template‐Directed Growth of Palladium Nanoparticles in Holey Single‐Layer Graphene for High‐Performance Room‐Temperature Hydrogen Sensing

Holey graphene (HG), formed by introducing nanoscale perforations into graphene sheets, combines the structural advantages of continuous sp 2 conjugation with the beneficial effects of high surface area and enhanced chemical reactivity associated with nanoscopic holes. Conventional HG fabrication methods often rely on harsh oxidative treatments that compromise graphene's intrinsic electronic properties by disrupting its sp 2 conjugation. A new approach is introduced to fabricate HG directly from single-layer graphene (SLG), using two-dimensional covalent organic frameworks (COFs) as a template followed by controlled oxygen plasma etching. This method preserves the integrity of the SLG's sp 2 network while producing well-defined holes with an average diameter of 2.7 nm. These hole edges act as reactive sites that facilitate the confined, autoreductive growth of palladium nanoparticles (PdNPs) without external reducing agents. The confined hole geometry prevents NP agglomeration and ensures a uniform size distribution. The resulting Pd@HG hybrid exhibits exceptional chemiresistive hydrogen sensing characteristics, including ultrahigh sensitivity, low detection limits, rapid response and recovery, and long-term stability under both dry and humid conditions. Mechanistic investigations reveal a two-step sensing process involving surface redox interactions and hydrogen absorption into the PdNP lattices. This strategy presents a scalable platform for integrating metal NPs within conductive carbon frameworks for advanced sensing applications.

chemical vapor deposition↗

DOE OSTI2024

The Impact of Sorbent Amendments for Mercury Remediation on the Viability of Soil Microorganisms

Mercury (Hg) remediation across contaminated environments in the United States is an ongoing project. As part of the Hg cleanup strategy at East Fork Poplar Creek (EFPC), located in Oak Ridge, TN, the deployment of sorbents is considered. However, the impact of sorbents on soil microorganisms is poorly understood. In this study, we investigated the effect of sorbents on soil microorganism viability and biofilm formation to assess soil health during sorbent application for Hg remediation. We specifically investigated the effect of two engineered sorbents, Organoclay PM-199 and Organoclay MRM (which are manufactured from clay minerals formulated for various remediation applications), on two gram-negative organisms ( Serratia marcescens and Burkholderia thailandensis ) isolated from the Hg-contaminated EFPC bank soil. Pure cultures of S. marcescens or B. thailandensis were amended with 5% (w/v) and 25% (w/v) PM-199 and MRM, respectively, for 9 days. The samples were harvested, and bacterial cell viability was determined using a BacLight staining kit. Results showed that the growth of sorbent-amended S. marcescens was inhibited in contrast to that of unamended control. Furthermore, biochemical assays were used to analyze bacterial biofilm formation and integral biofilm components. Our results suggest that biofilm formation by sorbent-amended S. marcescens was negatively affected. In contrast, B. thailandensis amended with low concentrations of MRM showed enhanced growth and notable differences in biofilm morphology. These results suggest that the use of organoclay PM-199 and MRM at higher concentrations in field studies may hinder the growth of specific soil microorganisms.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2022

Unravelling biogeochemical drivers of methylmercury production in an Arctic fen soil and a bog soil

Arctic tundra soils store a globally significant amount of mercury (Hg), which could be transformed to the neurotoxic methylmercury (MeHg) upon warming and thus poses serious threats to the Arctic ecosystem. However, our knowledge of the biogeochemical drivers of MeHg production is limited in these soils. Using substrate addition (acetate and sulfate) and selective microbial inhibition approaches, we investigated the geochemical drivers and dominant microbial methylators in 60-day microcosm incubations with two tundra soils: a circumneutral fen soil and an acidic bog soil, collected near Nome, Alaska, United States. Results showed that increasing acetate concentration had negligible influences on MeHg production in both soils. However, inhibition of sulfate-reducing bacteria (SRB) completely stalled MeHg production in the fen soil in the first 15 days, whereas addition of sulfate in the low-sulfate bog soil increased MeHg production by 5-fold, suggesting prominent roles of SRB in Hg(II) methylation. Without the addition of sulfate in the bog soil or when sulfate was depleted in the fen soil (after 15 days), both SRB and methanogens contributed to MeHg production. Analysis of microbial community composition confirmed the presence of several phyla known to harbor microorganisms associated with Hg(II) methylation in the soils. Lastly, the observations suggest that SRB and methanogens were mainly responsible for Hg(II) methylation in these tundra soils, although their relative contributions depended on the availability of sulfate and possibly syntrophic metabolisms between SRB and methanogens.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2024

Sorption kinetics and stability of conventional adsorbents for mercury remediation

In-situ remediation of mercury at numerous contaminated sites worldwide is a challenging and costly endeavor due to the persistency of this contaminant. In this study, we evaluated eight commercially available sorbent media ranging from carbon-, clays- and silica-based materials (PBC– Biochar, eSorb – Sorbster, nsPAC – Powdered Activated Carbon, fsPAC – Powdered Activated Carbon with Mackinawite, F300 – Filtrasorb 300, Si-SH – Silica Thiol, eBind – RemBind, Q-Clay – Organoclay PM-199), for their effectiveness in sorbing mercury (Hg 2+ ) and mercury complexed with dissolved organic matter (Hg-DOM). Under the chosen experimental conditions of this study, results showed that in the absence of DOM, the kinetic rates of Hg 2+ sorption onto the evaluated sorbents were in the order of 0.31 min-1 (Si-SH) to 2.98 min -1 (nsPAC), whereas in the presence of DOM, the rates varied from 0.16 min-1 (F300) to 0.95 min -1 (nsPAC). The measured sorption capacity for Hg 2+ in the absence of DOM varied from 3.02 mg/g (Q-Clay) to 35.15 mg/g (Si-SH), whereas in the presence of DOM, calculated partition coefficient (KD) ranged from 69.7 mL/g (Q-Clay) to 41,510 mL/g (Si-SH). Furthermore, kinetic data suggest liquid film diffusion was the rate-limiting steps governing mercury sorption onto the studied media. Overall, the obtained study parameters (kinetics/isotherm) are particularly important in informing robust engineering designs for deployment of the vast majority of evaluated sorbents. Thus, sorbent-based strategies offer viable solutions for cost-effective cleanup of mercury at industrially contaminated sites.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2021

Photometric sensing of heavy metal ions using a naphthoquinodimethyl- bis -thioamide dye: Selectivity & photophysics of the metal organic complexes

As Mother Nature is experiencing catastrophic environmental pollutions from both natural sources and anthropogenic activities, many scientists have been working around the clock to develop environmentally benign and cost-effective, yet sensitive, detection techniques for pollutants, especially heavy metal species (e.g. lead, cadmium, mercury, among others) that are deleterious to human health. Herein, we report a novel sulfur-containing small organic dye/sensor naphthoquinodimethyl-bis-thioamide (QDM), which was found to be particularly selective toward mercury ion (Hg 2+ ). Using a combination of UV-vis absorption, photoluminescence, and time-resolved pump-probe techniques, we established that QDM and Hg 2+ can form stable complex(es) due to the strong affinity of sulfur toward mercury. In this investigation, while a higher ratio of QDM:Hg 2+ was necessary to fully quench the fluorescence emission of QDM, only 1 equiv of the Hg 2+ ion was necessary to observe the sensing effect on the excited state photo-behavior(s) of QDM. Furthermore, the present results highlight a synergy between molecular sensors' selectivity/sensitivity and sensor-analytes dynamics.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2021

FOXM1-activated SIRT4 inhibits NF-κB signaling and NLRP3 inflammasome to alleviate kidney injury and podocyte pyroptosis in diabetic nephropathy

Highlights: • FOXM1 is downregulated in kidney tissues of patients with DN. • Overexpression of FOXM1 alleviates kidney injury in DN modeled mice. • Overexpression of FOXM1 reduces pyroptosis of HG-treated podocytes. • FOXM1 activates SIRT4 to inhibit the NFκB pathway and the NLRP3 inflammasome. • Downregulation of SIRT4 blocks the protective roles of FOXM1 in podocytes and mice. Forkhead box M1 (FOXM1) has been reported to play a protective role against acute kidney injury by driving tubular regeneration. This study aims to probe the function of FOXM1 in diabetic nephropathy (DN) and the molecules involved. FOXM1 was poorly expressed in DN-diseased kidney tissues. A murine model of DN was established, and podocytes cells (MPC5) were treated with high-glucose (HG) for in vitro studies. FOXM1 overexpression improved kidney function and reduced pathological changes in mice, and it increased the expression of the podocyte marker Nephrin in kidney tissues. In vitro, FOXM1 increased viability and reduced pyroptosis of the HG-treated MPC5 cells, and it elevated the expression of the podocyte marker Nephrin whereas reduced the expression of pyroptosis-related NLRP3 inflammasome and cleaved caspase 1. FOXM1 bound to the promoter of sirtuin 4 (SIRT4) to induce transcriptional activation. Downregulation of SIRT4 blocked the protective roles of FOXM1 both in vivo and in vitro. Phosphorylation of nuclear factor-kappa B (NF-κB) in HG-treated cells was suppressed by FOXM1 but restored after SIRT4 inhibition. In conclusion, this study suggested that FOXM1 transcriptionally activates SIRT4 and inhibits NF-κB signaling and the NLRP3 inflammasome to alleviate kidney injury and podocyte pyroptosis in DN.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2024

Thiol-Functionalized Adsorbents through Atomic Layer Deposition and Vapor-Phase Silanization for Heavy Metal Ion Removal

The removal of toxic heavy metal ions from water resources is crucial for environmental protection and public health. In this study, we address this challenge by developing a surface functionalization technique for the selective adsorption of these contaminants. Our approach involves atomic layer deposition (ALD) followed by vapor-phase silanization of porous substrates. We utilized porous silica gel powder (similar to 100 mu m particles, 89 m 2 /g surface area, similar to 30 nm pores) as an initial substrate. This powder was first coated with similar to 0.5 nm ALD Al 2 O 3 , followed by vapor-phase grafting of a thiol-functional silane. The modified powder, particularly in acidic conditions (pH = 4), showed high selectivity in adsorbing Cd(II), As(V), Pb(II), Hg(II), and Cu(II) heavy metal ions in mixed ion solutions over common benign ions (e.g., Na, K, Ca, and Mg). Langmuir adsorption isotherms and breakthrough adsorption studies were conducted to assess heavy metal binding affinity and revealed the order of Cd(II) < Pb(II) < Cu(II) < As(V) < Hg(II), with a significantly higher affinity for As(V) and Hg(II) ions. Time-dependent uptake studies demonstrated rapid removal of heavy metal ions from aqueous environments, with Hg(II) exhibiting the fastest adsorption kinetics on thiol-modified surfaces. Finally, these findings highlight the potential of ALD and vapor-phase silanization to create effective adsorbents for the targeted removal of hazardous contaminants from water.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2023

The Marginal Ice Zone as a dominant source region of atmospheric mercury during central Arctic summertime

Atmospheric gaseous elemental mercury (GEM) concentrations in the Arctic exhibit a clear summertime maximum, while the origin of this peak is still a matter of debate in the community. Based on summertime observations during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition and a modeling approach, we further investigate the sources of atmospheric Hg in the central Arctic. Simulations with a generalized additive model (GAM) show that long-range transport of anthropogenic and terrestrial Hg from lower latitudes is a minor contribution (~2%), and more than 50% of the explained GEM variability is caused by oceanic evasion. A potential source contribution function (PSCF) analysis further shows that oceanic evasion is not significant throughout the ice-covered central Arctic Ocean but mainly occurs in the Marginal Ice Zone (MIZ) due to the specific environmental conditions in that region. Our results suggest that this regional process could be the leading contributor to the observed summertime GEM maximum. In the context of rapid Arctic warming and the observed increase in width of the MIZ, oceanic Hg evasion may become more significant and strengthen the role of the central Arctic Ocean as a summertime source of atmospheric Hg.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2022

Dynamics of pectic homogalacturonan in cellular morphogenesis and adhesion, wall integrity sensing and plant development

Homogalacturonan (HG) is the most abundant pectin subtype in plant cell walls. Although it is a linear homopolymer, its modification states allow for complex molecular encoding. HG metabolism affects its structure, chemical properties, mobility and binding capacity, allowing it to interact dynamically with other polymers during wall assembly and remodelling and to facilitate anisotropic cell growth, cell adhesion and separation, and organ morphogenesis. HGs have also recently been found to function as signalling molecules that transmit information about wall integrity to the cell. Here we highlight recent advances in our understanding of the dual functions of HG as a dynamic structural component of the cell wall and an initiator of intrinsic and environmental signalling. Here, we also predict how HG might interconnect the cell wall, plasma membrane and intracellular components with transcriptional networks to regulate plant growth and development.

59 BASIC BIOLOGICAL SCIENCES↗

DOE OSTI2024

S-adenosyl-L-methionine is the unexpected methyl donor for the methylation of mercury by the membrane-associated HgcAB complex

Mercury (Hg) is a heavy metal that exhibits high biological toxicity. Monomethylmercury and dimethylmercury are neurotoxins and a significant environmental concern as they bioaccumulate and biomagnify within the aquatic food web. Microbial Hg methylation involves two proteins, HgcA and HgcB. Here, we show that HgcA and HgcB can be heterologously coexpressed, and the HgcAB complex can be purified. We demonstrated that HgcA is a membrane-associated cobalamin-dependent methyltransferase and HgcB is a ferredoxin-like protein containing two [4Fe-4S] clusters. Further, spectroscopic and kinetic results demonstrate that S-adenosyl-L-methionine (SAM) donates the methyl group to Hg in a two-step reaction involving a methylcob(III)alamin intermediate including Co-thiolate ligation from a conserved Cys residue. Our findings uncover a biological role for SAM in microbial Hg methylation.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2022

SDSS-IV MaNGA: Identification and multiwavelength properties of Type-1 AGN in the DR15 sample

ABSTRACT We present a method to identify type-1 active galactic nuclei (AGNs) in the central 3 arcsec integrated spectra of galaxies in the MaNGA DR15 sample. It is based on flux ratios estimates in spectral bands flanking the expected h α broad component h αBC. The high signal-to-noise ratio obtained (mean S/N = 84) permits the identification of h αBC without prior subtraction of the host galaxy (HG) stellar component. A final sample of 47 type-1 AGN is reported out of 4700 galaxies at z < 0.15. The results were compared with those from other methods based on the SDSS DR7 and MaNGA data. Detection of type-1 AGN in those works compared to our method goes from 26 per cent to 81 per cent. Spectral indexes were used to classify the type-1 AGN spectra according to different levels of AGN-HG contribution, finding 9 AGN-dominated, 14 intermediate, and 24 HG-dominated objects. Complementary data in NIR-MIR allowed us to identify type I AGN-dominated objects as blue and HG-dominated as red in the WISE colours. From NVSS and FIRST radio continuum data, we identify 5 HERGs (high-excitation radio galaxies) and 4 LERGs (low-excitation radio galaxies), three showing evidence of radio-jets in the FIRST maps. Additional X-ray data from ROSAT allowed us to build [O iii] and h αBC versus X-ray, NIR-MIR, and radio continuum diagrams, showing that L(h αBC) and L([O iii]) provide good correlations. The range in h αBC luminosity is wide 38 < logL(h αBC) < 44, with log FWHM(h αBC) ∼ 3–4, covering a range of Eddington ratios of −5.15 < log Lbol/LEdd < 0.70. Finally, we also identify and report ten possible changing-look AGN candidates.

Cortes-Suárez, Edgar↗

DOE OSTI2023

Superiority of compensatory reserve measurement compared with the Shock index for early and accurate detection of reduced central blood volume status

Shock index (SI) equals the ratio of heart rate (HR) to systolic blood pressure (SBP) with clinical evidence that it is more sensitive for trauma patient status assessment and prediction of outcome compared with either HR or SBP alone. We used lower body negative pressure (LBNP) as a human model of central hypovolemia and compensatory reserve measurement (CRM) validated for accurate tracking of reduced central blood volume to test the hypotheses that SI: (1) presents a late signal of central blood volume status; (2) displays poor sensitivity and specificity for predicting the onset of hemodynamic decompensation; and (3) cannot identify individuals at greatest risk for the onset of circulatory shock. We measured HR, SBP, and CRM in 172 human subjects (19–55 years) during progressive LBNP designed to determine tolerance to central hypovolemia as a model of hemorrhage. Subjects were subsequently divided into those with high tolerance (HT) (n = 118) and low tolerance (LT) (n = 54) based on completion of 60 mm Hg LBNP. The time course relationship between SI and CRM was determined and receiver operating characteristic (ROC) area under the curve (AUC) was calculated for sensitivity and specificity of CRM and SI to predict hemodynamic decompensation using clinically defined thresholds of 40% for CRM and 0.9 for SI. The time and level of LBNP required to reach a SI = 0.9 (~60 mm Hg LBNP) was significantly greater (p < 0.001) compared with CRM that reached 40% at ~40 mm Hg LBNP. Shock index did not differ between HT and LT subjects at 45 mm Hg LBNP levels. ROC AUC for CRM was 0.95 (95% CI = 0.94–0.97) compared with 0.91 (0.89–0.94) for SI (p = 0.0002). Despite high sensitivity and specificity, SI delays time to detect reductions in central blood volume with failure to distinguish individuals with varying tolerances to central hypovolemia.

60 APPLIED LIFE SCIENCES↗