Unraveling iron oxides as abiotic catalysts of organic phosphorus recycling in soil and sediment matrices.

In biogeochemical phosphorus cycling, iron oxide minerals are acknowledged as strong adsorbents of inorganic and organic phosphorus. Dephosphorylation of organic phosphorus is attributed only to biological processes, but iron oxides could also catalyze this reaction. Evidence of this abiotic catalysis has relied on monitoring products in solution, thereby ignoring iron oxides as both catalysts and adsorbents. Here we apply high-resolution mass spectrometry and X-ray absorption spectroscopy to characterize dissolved and particulate phosphorus species, respectively. In soil and sediment samples reacted with ribonucleotides, we uncover the abiotic production of particulate inorganic phosphate associated specifically with iron oxides. Reactions of various organic phosphorus compounds with the different minerals identified in the environmental samples reveal up to ten-fold greater catalytic reactivities with iron oxides than with silicate and aluminosilicate minerals. Importantly, accounting for inorganic phosphate both in solution and mineral-bound, the dephosphorylarion rates of iron oxides were within reported enzymatic rates in soils. Our findings thus imply a missing abiotic axiom for organic phosphorus mineralization in phosphorus cycling.

"Let's talk about it": Black youths' perceptions on the development of a school-based social media campaign.

The increase in social media mental health (MH) campaigns provides an opportunity to improve awareness and attitudes toward MH. However, racial disparities remain in these social media campaigns. Black youth who participated in MH social media campaigns reported lower levels of improvement in stigma and help-seeking than their White peers. We employed a youth participatory action research (YPAR) process to expand on a previous community-wide MH social media campaign (A. Thompson et al., 2021), focusing on a Central Midwest community. We studied Black adolescents' perceptions of MH stigma and help-seeking to determine essential features of a culturally responsive MH social media campaign for Black youth. With a lead youth-research collaborator, the research team designed the following two-staged study. The first stage consisted of four semistructured focus group interviews (FGIs) (N = 20), analyzed by using a rapid analysis strategy to obtain results for the development of the campaign. In the second stage, using YPAR's iterative and action-based process, five youth researchers collaborated with the research team on the campaign's design. Following the two stages, the researcher's thematic analysis resulted in three themes: (a) broadening horizons for campaign designers and MH professionals; (b) considering mistrust of schools and school personnel; and (c) diverse experiences, sustainability, and accessibility in a campaign. Findings indicated that while culturally responsive social media campaigns to promote MH can be designed, mistrust of adults in schools is likely to hinder the impact of such campaigns. Implications for school psychology practice and research are discussed. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Scaling of soil organic carbon in space and time in the Southern Coastal Plain, USA.

Soil organic carbon (SOC) is a dynamic soil property (DSP) that represents the largest portion of terrestrial carbon. Its relevance to carbon sequestration and the potential effects of land use on SOC storage, make it imperative to map across both space and time. Most regional-scale studies mapping SOC give static estimates and train different models for different periods with varying accuracies. We developed a flexible modeling approach called DSP-Scale to map SOC in both space and time. DSP-Scale uses ecological concepts and empirical data to predict DSP dynamics using inherent soil properties (static factors) and land cover changes (dynamic factors). We compiled SOC data for the 0-20 cm depth (SOC20) from 1441 points spanning a 25 million ha study area in the southeastern U.S. Coastal Plain, incorporating data from the Rapid Carbon Assessment, National Cooperative Soil Survey Soil Characterization database, and other regional studies. We developed a random forest model using climate, topography, soil survey, and land cover changes to predict SOC20 dynamics for five-year periods between 2001 and 2019. Our model explained 66 % and 59 % of the variation for the training and test data, respectively. Top predictors included mean annual precipitation, slope, and soil erosion class. Land cover 10 years before measurements of SOC20 was more important than current land cover for estimating SOC20. We estimated total SOC stocks of 207.1 and 208.3 Tg for 2001 and 2019, respectively. Highest gains of total SOC stock (0.9 Tg from 2001 to 2019) were associated with land cover change from mixed to evergreen forest. The greatest loss of total SOC stock (0.2 Tg) in the same period was associated with land cover change from pasture/hay to evergreen forest. We concluded that the DSP-Scale approach provides a flexible way to use dynamic and static factors affecting SOC stocks to predict changes in space and time at regional scales.

Ventilatory response of peripheral chemoreceptors to hypercapnia during exercise above the respiratory compensation point.

Peripheral hypercapnic chemosensitivity (PHC) is assessed as the change in ventilation in response to a rapid change in carbon dioxide pressures (Pco2). The increase in chemoresponse from rest to subrespiratory compensation point (RCP) exercise intensities is well-defined but less clear at intensities above the RCP when changes in known ventilatory stimulants occur. Twenty healthy subjects (n = 10 females) completed a maximal exercise test on 1 day, and on a subsequent day, transient hypercapnia was used to test PHC at multiple exercise stages. The transient hypercapnia involved two breaths of 10% CO2 repeated five times during each of the following: sitting at rest on the cycle ergometer, cycling at 40% wmax, cycling at 85% Wmax, at rest on the cycle ergometer immediately following the 85% stage, and cycling at 40% Wmax again following the postexercise rest. The PHC was not different across exercise intensities (0.98 ± 0.37 vs. 0.91 ± 0.39 vs. 0.92 ± 0.42 L·min-1·mmHg-1 for first 40% wmax, 85% wmax and second 40% Wmax, respectively (P = 0.45). There were no differences in PHC between presupra-RCP exercise rest and postsupra-RCP exercise rest (0.52 ± 0.23 vs. 0.53 ± 0.24 L·min-1·mmHg-1, P = 0.8003). Using a repeated-measures correlation to account for within-participant changes, there was a significant relationship between the end-tidal Pco2 and PHC for the 85% intensity (r = 0.5, P < 0.0001) when end-tidal Pco2 was dynamic between the trials. We conclude that the physiological changes (e.g., metabolic milieu and temperature) produced with supra-RCP exercise do not further augment PHC, and that the prestimulus end-tidal Pco2 modulates the PHC.NEW & NOTEWORTHY Exercise at intensities above the respiratory compensation point did not further augment peripheral hypercapnic chemosensitivity (PHC). Moreover, the PHC was not different during a preexercise resting state compared with rest immediately after intense exercise. The lack of differences across both comparisons suggests that exercise itself appears to sensitize the PHC.

Structure-Based Optimization of Selective and Brain Penetrant CK1δ Inhibitors for the Treatment of Circadian Disruptions.

Neuropsychiatric disorders such as major depressive disorders and schizophrenia are often associated with disruptions to the normal 24 h sleep wake cycle. Casein kinase 1 (CK1δ) is an integral part of the molecular machinery that regulates circadian rhythms. Starting from a cluster of bicyclic pyrazoles identified from a virtual screening effort, we utilized structure-based drug design to identify and reinforce a unique "hinge-flip" binding mode that provides a high degree of selectivity for CK1δ versus the kinome. Pharmacokinetics, brain exposure, and target engagement as measured by ex vivo autoradiography are described for advanced analogs.

A Critical Look at Colloid Generation, Stability, and Transport in Redox-Dynamic Environments: Challenges and Perspectives.

Colloid generation, stability, and transport are important processes that can significantly influence the fate and transport of nutrients and contaminants in environmental systems. Here, we critically review the existing literature on colloids in redox-dynamic environments and summarize the current state of knowledge regarding the mechanisms of colloid generation and the chemical controls over colloidal behavior in such environments. We also identify critical gaps, such as the lack of universally accepted cross-discipline definition and modeling infrastructure that hamper an in-depth understanding of colloid generation, behavior, and transport potential. We propose to go beyond a size-based operational definition of colloids and consider the functional differences between colloids and dissolved species. We argue that to predict colloidal transport in redox-dynamic environments, more empirical data are needed to parametrize and validate models. We propose that colloids are critical components of element budgets in redox-dynamic systems and must urgently be considered in field as well as lab experiments and reactive transport models. We intend to bring further clarity and openness in reporting colloidal measurements and fate to improve consistency. Additionally, we suggest a methodological toolbox for examining impacts of redox dynamics on colloids in field and lab experiments.

Understanding the Unmet Accommodation Needs of People Working with Mental or Cognitive Conditions: The Importance of Gender, Gendered Work, and Employment Factors.

PURPOSE: Workplace support needs for women and men living with mental health conditions are not well understood. This study examined workplace accommodation and support needs among women and men with and without mental health or cognitive conditions and individual and workplace factors associated with having unmet needs. METHODS: A cross-sectional survey of 3068 Canadian workers collected information on disability, gender, gendered occupations, job conditions, work contexts, and workplace accommodations. Multivariable logistic regression analyses examined gender- and disability-based differences in unmet needs for workplace flexibility, work modifications, and health benefits, and the association of work context (i.e., work schedule, job sector) and job conditions (i.e., precarious work) on the likelihood of unmet accommodation needs. The additive (i.e., super- or sub-additive) and multiplicative effects of disability, gender, and occupational gender distribution on the probability of unmet accommodation needs were also assessed. RESULTS: The most common unmet workplace accommodation was work modifications reported by 35.9% of respondents with mental/cognitive disability and workplace flexibility reported by 19.6% of individuals without a mental/cognitive disability. Women, employees in female dominant occupations, and participants with mental/cognitive disabilities were more likely to report unmet needs compared with men, employees in non-female dominant occupations, and participants without disabilities but these findings were largely explained by differences in job conditions and work contexts. No interacting effects on the likelihood of reporting unmet needs for workplace accommodations were observed. CONCLUSIONS: To support employee mental health, attention is needed to address work contexts and job conditions, especially for people working with mental/cognitive disabilities, women, and workers in female-dominated occupations where unmet accommodation needs are greatest.

The primacy of temporal dynamics in driving spatial self-organization of soil iron redox patterns.

This study investigates mechanisms that generate regularly spaced iron-rich bands in upland soils. These striking features appear in soils worldwide, but beyond a generalized association with changing redox, their genesis is yet to be explained. Upland soils exhibit significant redox fluctuations driven by rainfall, groundwater changes, or irrigation. Pattern formation in such systems provides an opportunity to investigate the temporal aspects of spatial self-organization, which have been heretofore understudied. By comparing multiple alternative mechanisms, we found that regular iron banding in upland soils is explained by coupling two sets of scale-dependent feedbacks, the general principle of Turing morphogenesis. First, clay dispersion and coagulation in iron redox fluctuations amplify soil Fe(III) aggregation and crystal growth to a level that negatively affects root growth. Second, the activation of this negative root response to highly crystalline Fe(III) leads to the formation of rhythmic iron bands. In forming iron bands, environmental variability plays a critical role. It creates alternating anoxic and oxic conditions for required pattern-forming processes to occur in distinctly separated times and determines durations of anoxic and oxic episodes, thereby controlling relative rates of processes accompanying oxidation and reduction reactions. As Turing morphogenesis requires ratios of certain process rates to be within a specific range, environmental variability thus modifies the likelihood that pattern formation will occur. Projected changes of climatic regime could significantly alter many spatially self-organized systems, as well as the ecological functioning associated with the striking patterns they present. This temporal dimension of pattern formation merits close attention in the future.

Development of small molecule inhibitors of natural killer group 2D receptor (NKG2D).

Natural killer group 2D (NKG2D) is a homodimeric activating immunoreceptor whose function is to detect and eliminate compromised cells upon binding to the NKG2D ligands (NKG2DL) major histocompatibility complex (MHC) molecules class I-related chain A (MICA) and B (MICB) and UL16 binding proteins (ULBP1-6). While typically present at low levels in healthy cells and tissue, NKG2DL expression can be induced by viral infection, cellular stress or transformation. Aberrant activity along the NKG2D/NKG2DL axis has been associated with autoimmune diseases due to the increased expression of NKG2D ligands in human disease tissue, making NKG2D inhibitors an attractive target for immunomodulation. Herein we describe the discovery and optimization of small molecule PPI (protein-protein interaction) inhibitors of NKG2D/NKG2DL. Rapid SAR was guided by structure-based drug design and accomplished by iterative singleton and parallel medicinal chemistry synthesis. These efforts resulted in the identification of several potent analogs (14, 21, 30, 45) with functional activity and improved LLE.

Electron Transfer, Atom Exchange, and Transformation of Iron Minerals in Soils: The Influence of Soil Organic Matter.

Despite substantial experimental evidence of electron transfer, atom exchange, and mineralogical transformation during the reaction of Fe(II)aq with synthetic Fe(III) minerals, these processes are rarely investigated in natural soils. Here, we used an enriched Fe isotope approach and Mössbauer spectroscopy to evaluate how soil organic matter (OM) influences Fe(II)/Fe(III) electron transfer and atom exchange in surface soils collected from Luquillo and Calhoun Experimental Forests and how this reaction might affect Fe mineral composition. Following the reaction of 57Fe-enriched Fe(II)aq with soils for 33 days, Mössbauer spectra demonstrated marked electron transfer between sorbed Fe(II) and the underlying Fe(III) oxides in soils. Comparing the untreated and OM-removed soils indicates that soil OM largely attenuated Fe(II)/Fe(III) electron transfer in goethite, whereas electron transfer to ferrihydrite was unaffected. Soil OM also reduced the extent of Fe atom exchange. Following reaction with Fe(II)aq for 33 days, no measurable mineralogical changes were found for the Calhoun soils enriched with high-crystallinity goethite, while Fe(II) did drive an increase in Fe oxide crystallinity in OM-removed LCZO soils having low-crystallinity ferrihydrite and goethite. However, the presence of soil OM largely inhibited Fe(II)-catalyzed increases in Fe mineral crystallinity in the LCZO soil. Fe atom exchange appears to be commonplace in soils exposed to anoxic conditions, but its resulting Fe(II)-induced recrystallization and mineral transformation depend strongly on soil OM content and the existing soil Fe phases.

Laboratory evaluation of open source and commercial electrical conductivity sensor precision and accuracy: How do they compare?

Variation in the electrical conductivity (EC) of water can reveal environmental disturbance and natural dynamics, including factors such as anthropogenic salinization. Broader application of open source (OS) EC sensors could provide an inexpensive method to measure water quality. While studies show that other water quality parameters can be robustly measured with sensors, a similar effort is needed to evaluate the performance of OS EC sensors. To address this need, we evaluated the accuracy (mean error, %) and precision (sample standard deviation) of OS EC sensors in the laboratory via comparison to EC calibration standards using three different OS and OS/commercial-hybrid (OS/C) EC sensors and data logger configurations and two commercial (C) EC sensors and data logger configurations. We also evaluated the effect of cable length (7.5 m and 30 m) and sensor calibration on OS sensor accuracy and precision. We found a significant difference between OS sensor mean accuracy (3.08%) and all other sensors combined (9.23%). Our study also found that EC sensor precision decreased across all sensor configurations with increasing calibration standard EC. There was also a significant difference between OS sensor mean precision (2.85 µS/cm) and the mean precision of all other sensors combined (9.12 µS/cm). Cable length did not affect OS sensor precision. Furthermore, our results suggest that future research should include evaluating how performance is impacted by combining OS sensors with commercial data loggers as this study found significantly decreased performance in OS/commercial-hybrid sensor configurations. To increase confidence in the reliability of OS sensor data, more studies such as ours are needed to further quantify OS sensor performance in terms of accuracy and precision across different settings and OS sensor and data collection platform configurations.

A 3D printable alloy designed for extreme environments.

Multiprincipal-element alloys are an enabling class of materials owing to their impressive mechanical and oxidation-resistant properties, especially in extreme environments1,2. Here we develop a new oxide-dispersion-strengthened NiCoCr-based alloy using a model-driven alloy design approach and laser-based additive manufacturing. This oxide-dispersion-strengthened alloy, called GRX-810, uses laser powder bed fusion to disperse nanoscale Y2O3 particles throughout the microstructure without the use of resource-intensive processing steps such as mechanical or in situ alloying3,4. We show the successful incorporation and dispersion of nanoscale oxides throughout the GRX-810 build volume via high-resolution characterization of its microstructure. The mechanical results of GRX-810 show a twofold improvement in strength, over 1,000-fold better creep performance and twofold improvement in oxidation resistance compared with the traditional polycrystalline wrought Ni-based alloys used extensively in additive manufacturing at 1,093 °C5,6. The success of this alloy highlights how model-driven alloy designs can provide superior compositions using far fewer resources compared with the 'trial-and-error' methods of the past. These results showcase how future alloy development that leverages dispersion strengthening combined with additive manufacturing processing can accelerate the discovery of revolutionary materials.

Usability and social consequences of the early identification system as a universal screener for social, emotional, and behavioral risks.

The Early Identification System (EIS) was developed to overcome many of the usability challenges of school-based behavior screeners. Several prior studies have documented the technical adequacy of the EIS. The present study expanded this work by examining the use, relevance, values implications, and social consequence of EIS implementation in a sample of 54 K-12 schools and 23,104 students in the Midwestern United States. We found that nearly all schools, teachers, and students completed the EIS as planned. Schools used the data to provide universal, selective, and indicated services to a high percentage of students identified with risks as well as to plan professional development for educators based on the screening data. Seventy-nine percent of schools implemented the EIS system with high fidelity, and fidelity was unrelated to student demographic composition within schools. These findings suggest that the EIS may overcome many of the usability barriers that plague common behavior screeners. Limitations and implications for advancing the science of social consequence evaluation are discussed. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Identification of small-molecule protein-protein interaction inhibitors for NKG2D.

NKG2D (natural-killer group 2, member D) is a homodimeric transmembrane receptor that plays an important role in NK, γδ+, and CD8+ T cell-mediated immune responses to environmental stressors such as viral or bacterial infections and oxidative stress. However, aberrant NKG2D signaling has also been associated with chronic inflammatory and autoimmune diseases, and as such NKG2D is thought to be an attractive target for immune intervention. Here, we describe a comprehensive small-molecule hit identification strategy and two distinct series of protein-protein interaction inhibitors of NKG2D. Although the hits are chemically distinct, they share a unique allosteric mechanism of disrupting ligand binding by accessing a cryptic pocket and causing the two monomers of the NKG2D dimer to open apart and twist relative to one another. Leveraging a suite of biochemical and cell-based assays coupled with structure-based drug design, we established tractable structure-activity relationships with one of the chemical series and successfully improved both the potency and physicochemical properties. Together, we demonstrate that it is possible, albeit challenging, to disrupt the interaction between NKG2D and multiple protein ligands with a single molecule through allosteric modulation of the NKG2D receptor dimer/ligand interface.

A Sensibility Assessment of the Job Demands and Accommodation Planning Tool (JDAPT): A Tool to Help Workers with an Episodic Disability Plan Workplace Support.

Purpose Sensibility refers to a tool's comprehensiveness, understandability, relevance, feasibility, and length. It is used in the early development phase to begin assessing a new tool or intervention. This study examined the sensibility of the job demands and accommodation planning tool (JDAPT). The JDAPT identifies job demands related to physical, cognitive, interpersonal, and working conditions to better target strategies for workplace supports and accommodations aimed at assisting individuals with chronic health conditions. Methods Workers with a chronic health condition and workplace representatives were recruited from health charities, workplaces, and newsletters using convenience sampling. Cognitive interviews assessed the JDAPT's sensibility. A 70% endorsement rate was the minimum level of acceptability for sensibility concepts. A short screening tool also was administered, and answers compared to the complete JDAPT. Results Participants were 46 workers and 23 organizational representatives (n = 69). Endorsements highly exceeded the 70% cut-off for understandability, relevance, and length. Congruence between screening questions and the complete JDAPT suggested both workers and organizational representatives overlooked job demands when completing the screener. Participants provided additional examples and three new items to improve comprehensiveness. The JDAPT was rated highly relevant and useful, although not always easy to complete for someone with an episodic condition. Conclusions This study highlights the need for tools that facilitate accommodations for workers with episodic disabilities and provides early evidence for the sensibility of the JDAPT.

Bringing soil chemistry to environmental health science to tackle soil contaminants.

With an estimated five million sites worldwide, soil contamination is a global-scale threat to environmental and human health. Humans continuously interact with soil, both directly and indirectly, making soils potentially significant sources of exposure to contaminants. Soil chemists are thus a potentially dynamic part of a collaborative cohort attacking environmental health science problems, yet collaborations between soil chemists and environmental heath scientists remain infrequent. In this commentary, we discuss the unique properties of soils that influence contaminants, as well as ways that soil chemists can contribute to environmental health research. Additionally, we describe barriers to, and needs for, the integration of soil chemistry expertise in environmental health science research with a focus on the future.

Redox Properties of Solid Phase Electron Acceptors Affect Anaerobic Microbial Respiration under Oxygen-Limited Conditions in Floodplain Soils.

Mountain floodplain soils often show spatiotemporal variations in redox conditions that arise due to changing hydrology and resulting biogeochemistry. Under oxygen-depleted conditions, solid phase terminal electron acceptors (TEAs) can be used in anaerobic respiration. However, it remains unclear to what degree the redox properties of solid phases limit respiration rates and hence organic matter degradation. Here, we assess such limitations in soils collected across a gradient in native redox states from the Slate River floodplain (Colorado, U.S.A.). We incubated soils under anoxic conditions and quantified CO2 production and microbial Fe(III) reduction, the main microbial metabolic pathway, as well as the reactivity of whole-soil solid phase TEAs toward mediated electrochemical reduction. Fe(III) reduction occurred together with CO2 production in native oxic soils, while neither Fe(II) nor CO2 production was observed in native anoxic soils. Initial CO2 production rates increased with increasing TEA redox reactivity toward mediated electrochemical reduction across all soil depths. Low TEA redox reactivity appears to be caused by elevated Fe(II) concentrations rather than crystallinity of Fe(III) phases. Our findings illustrate that the buildup of Fe(II) in systems with long residence times limits the thermodynamic viability of dissimilatory Fe(III) reduction and thereby limits the mineralization of organic carbon.

Biological Oxidation of Fe(II)-Bearing Smectite by Microaerophilic Iron Oxidizer Sideroxydans lithotrophicus Using Dual Mto and Cyc2 Iron Oxidation Pathways.

Fe(II) clays are common across many environments, making them a potentially significant microbial substrate, yet clays are not well established as an electron donor. Therefore, we explored whether Fe(II)-smectite supports the growth of Sideroxydans lithotrophicus ES-1, a microaerophilic Fe(II)-oxidizing bacterium (FeOB), using synthesized trioctahedral Fe(II)-smectite and 2% oxygen. S. lithotrophicus grew substantially and can oxidize Fe(II)-smectite to a higher extent than abiotic oxidation, based on X-ray near-edge spectroscopy (XANES). Sequential extraction showed that edge-Fe(II) is oxidized before interior-Fe(II) in both biotic and abiotic experiments. The resulting Fe(III) remains in smectite, as secondary minerals were not detected in biotic and abiotic oxidation products by XANES and Mössbauer spectroscopy. To determine the genes involved, we compared S. lithotrophicus grown on smectite versus Fe(II)-citrate using reverse-transcription quantitative PCR and found that cyc2 genes were highly expressed on both substrates, while mtoA was upregulated on smectite. Proteomics confirmed that Mto proteins were only expressed on smectite, indicating that ES-1 uses the Mto pathway to access solid Fe(II). We integrate our results into a biochemical and mineralogical model of microbial smectite oxidation. This work increases the known substrates for FeOB growth and expands the mechanisms of Fe(II)-smectite alteration in the environment.

Secondary Mineral Formation and Carbon Dynamics during FeS Oxidation in the Presence of Dissolved Organic Matter.

Iron (Fe) minerals constitute a major control on organic carbon (OC) storage in soils and sediments. While previous research has mainly targeted Fe (oxyhydr)oxides, the impact of Fe sulfides and their subsequent oxidation on OC dynamics remains unresolved in redox-fluctuating environments. Here, we investigated the impact of dissolved organic matter (DOM) on FeS oxidation and how FeS and its oxidation may alter the retention and nature of DOM. After the anoxic reaction of DOM with FeS, FeS preferentially removed high-molecular-weight and nitrogen-rich compounds and promoted the formation of aqueous sulfurized organic molecules, according to Fourier transform-ion cyclotron resonance-mass spectrometry (FT-ICR-MS) analysis. When exposed to O2, FeS oxidized to nanocrystalline lepidocrocite and additional aqueous sulfurized organic compounds were generated. The presence of DOM decreased the particle size of the resulting nano-lepidocrocite based on Mössbauer spectroscopy. Following FeS oxidation, most solid-phase OC remained associated with the newly formed lepidocrocite via a monodentate chelating mechanism (based on FTIR analysis), and FeS oxidation caused only a slight increase in the solubilization of solid-phase OC. Collectively, this work highlights the under-appreciated role of Fe sulfides and their oxidation in driving OC transformation and preservation.