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Iodinated disinfection by-products (I-DBPs) are of growing concern due to their elevated toxicity compared to their chlorinated counterparts, with links to adverse health effects such as bladder cancer and miscarriages. Medical imaging agents like iohexol, commonly used in healthcare facilities, introduce iodine into wastewater systems. This study investigates the photodegradation of iohexol and the subsequent formation of products, including I-DBPs, during simulated final wastewater treatment under chlorination and sunlight exposure. Experiments were conducted with solutions containing 30 μM iohexol, 3 mg L−1 humic acids, and 5.5 mg L−1 hypochlorite. Samples were irradiated at λ ≥ 295 nm and subject to ion chromatography monitoring of I−, IO3−, Cl−, and ClO3−, providing mechanistic insight into the fate of iodide released from iohexol. UV-visible spectroscopy was employed to monitor the degradation profile of iohexol and the concurrent release of iodide. Electrospray ionization mass spectrometry (ESI-MS) identified a range of anionic products based on their mass-to-charge ratios (m/z), including low molecular weight carboxylic acids, their carcinogenic haloacetic derivatives (chloroacetic acid (m/z 93), iodoacetic acid (IAA, m/z 185), and hydroxyiodoacetic acid (m/z 201)) as well as phenolic halides. Notably, IAA was present at a concentration of 0.16 μM at the conclusion of the reaction. These findings elucidate photodeiodination-coupled radical attack, photooxidative cleavage, and halogenation transformation pathways of iodinated compounds during disinfection and underscore the potential risks associated with their presence in wastewater. The results provide valuable insights for medical facilities and wastewater treatment plants aiming to mitigate the formation of hazardous I-DBPs. 

Not AvailableTwo-dimensional halide perovskites (2D-HPs) are of significant interest for their applications in optoelectronic devices. Part of this increased interest in 2D-HPs stems from their increased stability relative to their 3D counterparts. Here, the origin of higher stability in 2D-HPs is mainly attributed to the bulky ammonium cation layers, which can act as a blocking layer against moisture and oxygen ingression and ion diffusion. While 2D-HPs have demonstrated increased stability, it is not clear how the structure of the ammonium ion impacts the material stability. Herein, we investigate how the structure of ammonium cations, including three n-alkyl ammoniums, phenethylammonium (PEA) and five PEA derivatives, anilinium (An), benzylammonium (BzA), and cyclohexylmethyl ammonium (CHMA), affects the crystal structure and air, water, and oxygen stability of 2D tin halide perovskites (2D-SnHPs). We find that stability is influenced by several factors, including the molecular packing and intermolecular interactions in the organic layer, steric effects around the ammonium group, the orientation distribution of the 2D sheets, and the hydrophobicity of the perovskite film surface. With superior hydrophobicity, strong interactions between organic layers, and a high extent of parallel oriented inorganic sheets, the 2-(4-trifluoromethyl-phenyl)-ethylammonium (4-TFMPEA) ion forms the most stable 2D-SnHP among the 12 ammonium cations investigated. 

Abstract The use of γ‐Al₂O₃‐supported Ni catalysts promoted with either Cu or Fe was investigated for the reductive catalytic fractionation (RCF) of hybrid poplar in methanol at 200 and 250 °C. The effectiveness of lignin depolymerization was quantified in terms of the lignin oil production, the quantity and distribution of identifiable monomers present in the lignin oil, and the yield of residual solids. All of the Ni‐based catalysts tested provided improved yields of lignin oil and monomers, along with reduced char formation, relative to blank (sans catalyst) runs. The highest monomer yield of 51 % was obtained at 250 °C over a 20 wt.% Ni‐5 wt.% Cu/Al₂O₃catalyst, the improved performance obtained through Cu promotion being attributed to the ability of Cu to facilitate NiO reduction, resulting in an increased amount of Ni⁰on the catalyst surface and, consequently, improved hydrogenation activity. The main monomers formed were propanol‐, propyl‐ and propenyl‐substituted guaiacol and syringol, the S/G ratio of the products corresponding closely to that in the native lignin. 

Abstract BackgroundUndergraduate engineering students experiencing distress are less likely than peers to ask for professional help. A population‐specific instrument to facilitate the identification of factors that influence mental healthcare utilization could guide development and testing of interventions to increase help seeking. PurposeWe used mixed methods guided by the Integrated Behavioral Model (IBM) to develop and evaluate the Undergraduate Engineering Mental Health Help‐Seeking Instrument (UE‐MH‐HSI). MethodFirst, we adapted existing measures of mental health help‐seeking intention and mechanisms (i.e., attitudes, perceived norm: injunctive, perceived norm: descriptive, personal agency: autonomy, personal agency: capacity). Second, we coded qualitative interviews (N = 33) to create population‐specific mental health help‐seeking belief measures (i.e., outcome beliefs, experiential beliefs, beliefs about others' expectations, beliefs about others' behavior, beliefs about barriers and facilitators). Third, we tested the psychometric properties using data from 596 undergraduate engineering students at a historically White, research‐focused institution in southern United States. ResultsPsychometric analyses indicated that (1) help‐seeking mechanism and intention measures demonstrated unidimensionality, internal consistency, construct replicability, and sufficient variability; (2) mechanism measures demonstrated criterion evidence of validity; and (3) most items within the belief measures demonstrated sufficient variability and convergent evidence of validity. ConclusionsThe UE‐MH‐HSI is an evidence‐based tool for investigating mental health help‐seeking factors and their relationship to help‐seeking behavior, well‐being, academic success, and engineering identity formation. Guidelines for use are provided. 

The estrous cycle regulates rhythms of locomotor activity, body temperature, and circadian gene expression. In female mice, activity increases on the night of proestrus, when elevated estrogens cause ovulation. Exogenous estradiol regulates eating behavior rhythms in female mice fed a high-fat diet, but it is unknown whether endogenous estrogens regulate eating rhythms. In this study, we investigated whether diurnal and circadian eating behavior rhythms change systematically across the estrous cycle. We first studied diurnal eating behavior rhythms in female C57BL/6J mice in 12L:12D. Estrous cycle stages were determined by vaginal cytology while eating behavior and wheel revolutions were continuously measured. The mice had regular 4- to 5-day estrous cycles. Consistent with prior studies, the greatest number of wheel revolutions occurred on the night of proestrus into estrus when systemic levels of estrogens peak. The amplitude, or robustness, of the eating behavior rhythm also fluctuated with 4- to 5-day cycles and peaked primarily during proestrus or estrus. The phases of eating behavior rhythms fluctuated, but not at 4- or 5-day intervals, and phases did not correlate with estrous cycle stages. After ovariectomy, the eating behavior rhythm amplitude fluctuated at irregular intervals. In constant darkness, the amplitude of the circadian eating behavior rhythm peaked every 4 or 5 days and coincided with the circadian day that had the greatest number of wheel revolutions, a marker of proestrus. These data suggest that fluctuations of ovarian hormones across the estrous cycle temporally organize the robustness of circadian eating behavior rhythms so that it peaks during ovulation and sexual receptivity. 

Abstract In both chemical and electrochemical doping of organic semiconductors (OSCs), a counterion, either from the electrolyte or ionized dopant, balances the charge introduced to the OSC. Despite the large influence of this counterion on OSC optical and electronic response, there remains substantial debate on how a fundamental parameter, ion size, impacts these properties. This work resolves much of this debate by accounting for two doping regimes. In the low‐doping regime, the Coulomb binding energies between charge carriers on the OSC and the counterions are significant, and larger counterions lead to decreased Coulomb interactions, more delocalized charge carriers, and higher electrical conductivities. In the high‐doping regime, the Coulomb binding energies become negligible due to the increased dielectric constant of the films and a smoothing of the energy landscape; thereby, the electrical conductivities depend primarily on the extent of morphological disorder in the OSC. Moreover, in regioregular poly(3‐hexylthiophene), rr‐P3HT, smaller counterions lead to greater bipolaron concentrations in the low‐doping regime due to the increased Coulomb interactions. Emphasizing the impact of the counterion size, it is shown that larger counterions can lead to increased thermoelectric power factors for rr‐P3HT. 

ABSTRACT Past work has shown that group formation in foraging animals aids in resource acquisition and reduces the number of interactions with predators. However, group formation can also increase competition for resources among group members. Here, we model how the individual costs and benefits of group formation drive group size. Our model predicts that when competition for resources occurs within and between groups, forager group size will exhibit a one‐third power‐law relationship with population abundance. However, if groups form due to intragroup competition and predation, we predict either a one‐half power‐law relationship with population abundance or a constant group size depending on the coupling between predator and prey. Using empirical data on group foraging birds and ungulates, we found a scaling relationship consistent with the one‐third power‐law, suggesting that hierarchical competition drives the average group size. Our results support work highlighting the importance of density‐dependent group formation in maintaining population stability. 

Summary White oak (Quercus alba) is an abundant forest tree species across eastern North America that is ecologically, culturally, and economically important.We report the first haplotype‐resolved chromosome‐scale genome assembly ofQ. albaand conduct comparative analyses of genome structure and gene content against other published Fagaceae genomes. We investigate the genetic diversity of this widespread species and the phylogenetic relationships among oaks using whole genome data.Despite strongly conserved chromosome synteny and genome size acrossQuercus, certain gene families have undergone rapid changes in size, including defense genes. Unbiased annotation of resistance (R) genes across oaks revealed that the overall number of R genes is similar across species – as are the chromosomal locations of R gene clusters – but, gene number within clusters is more labile. We found thatQ. albahas high genetic diversity, much of which predates its divergence from other oaks and likely impacts divergence time estimations. Our phylogenetic results highlight widespread phylogenetic discordance across the genus.The white oak genome represents a major new resource for studying genome diversity and evolution inQuercus. Additionally, we show that unbiased gene annotation is key to accurately assessing R gene evolution inQuercus. 

Abstract Hippodamia convergens—the convergent lady beetle, has been used extensively in augmentative biological control of aphids, thrips, and whiteflies across its native range in North America, and was introduced into South America in the 1950s. OverwinteringH. convergenspopulations from its native western range in the United States are commercially collected and released across its current range in the eastern USA, with little knowledge of the effectiveness of its augmentative biological control. Here we use a novel ddRADseq‐based SNP/haplotype discovery approach to estimate its range‐wide population diversity, differentiation, and recent evolutionary history. Our results indicate (1) significant population differentiation among eastern USA, western USA, and South American populations ofH. convergens, with (2) little to no detectable recent admixture between them, despite repeated population augmentation, and (3) continued recent population size expansion across its range. These results contradict previous findings using microsatellite markers. In light of these new findings, the implications for the effectiveness of augmentative biological control usingH. convergensare discussed. Additionally, because quantifying the non‐target effects of augmentative biological control is a difficult problem in migratory beetles, our results could serve as a cornerstone in improving and predicting the efficacy of future releases ofH. convergensacross its range. 

Abstract The spectacular variation in species forms and richness across space and time can be explored using sophisticated and powerful tools recently developed by evolutionary modellers. In this contribution, we ask if the classic ‘Simpsonian’ view of tachytelic (fast), horotelic (standard) and bradytelic (slow) diversification rates can be distinguished with currently available tools and data. A neglected topic here is the role that the uncertainty of diversification rate estimates plays, where the lack of in‐depth uncertainty measures could hinder our ability to confidently suggest differences in speciation or extinction rates in any given comparison.We propose quantifying the relative uncertainty of diversification estimates, to better compare diversification tempo across phylogenies of different sizes and ages. We present three case studies, using the most popular models for diversification rate estimation, with or without fossils, to investigate claims of bradytely or tachytely. Using summary statistics and linear models, we ask if point estimates of diversification rates are comparable across clades. More specifically, we fit a linear model to understand which phylogenetic tree properties (including size and age) may affect the uncertainty of diversification estimates.We found the ‘Goldilocks of uncertainty’: Phylogenies that are young with insufficient tips or that are old increase the uncertainty of diversification estimates. The choice of diversification modelling approach is independent of the pattern of diversification rates decaying exponentially with clade age.In practice, we still cannot confidently compare diversification rates or their variation, due to uncertainties stemming from clade age, sample size and biased sampling. We emphasize the need for researchers to focus on estimating and presenting uncertainty in their estimates. Such uncertainty estimates are currently absent from many publications, limiting our ability to compare the tempo of diversifications across the tree of life. We conclude by proposing solutions and guidelines to encourage new studies for measure uncertainty.