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This article outlines the career of Dr. J. Douglas McDonald, professor of psychology at the University of North Dakota (UND) and the director of the UND Indians into Psychology Doctoral Education Program. During graduate school, McDonald grew determined to develop a program that would assist American Indian students with entering the field of psychology in order to serve native populations across the United States and build cross-cultural competency and allyship within the psychological community. Upon graduating with a PhD in clinical psychology from the University of South Dakota, he created the flagship Indians into Psychology Doctoral Education program at UND, which meets these objectives, and has directed it ever since. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Lithium-ion batteries (LiBs) are used globally as a key component of clean and sustainable energy infrastructure, and emerging LiB technologies have incorporated a class of per- and polyfluoroalkyl substances (PFAS) known as bis-perfluoroalkyl sulfonimides (bis-FASIs). PFAS are recognized internationally as recalcitrant contaminants, a subset of which are known to be mobile and toxic, but little is known about environmental impacts of bis-FASIs released during LiB manufacture, use, and disposal. Here we demonstrate that environmental concentrations proximal to manufacturers, ecotoxicity, and treatability of bis-FASIs are comparable to PFAS such as perfluorooctanoic acid that are now prohibited and highly regulated worldwide, and we confirm the clean energy sector as an unrecognized and potentially growing source of international PFAS release. Results underscore that environmental impacts of clean energy infrastructure merit scrutiny to ensure that reduced CO 2 emissions are not achieved at the expense of increasing global releases of persistent organic pollutants., (© 2024. The Author(s).)

The development and production of engineered 2D nanomaterials are expanding exponentially, increasing the risk of their release into the aquatic environment. A recent study showed 2D MnO 2 nanosheets, under development for energy and biomedical applications, dissolve upon interaction with biological reducing agents, resulting in depletion of intracellular glutathione levels within fish gill cells. However, little is known concerning their toxicity and interactions with subcellular organelles. To address this gap, we examined cellular uptake, cytotoxicity and mitochondrial effects of 2D MnO 2 nanosheets using an in vitro fish gill cell line to represent a target tissue of rainbow trout, a freshwater indicator species. The data demonstrate cellular uptake of MnO 2 nanosheets into lysosomes and potential mechanisms of dissolution within the lysosomal compartment. MnO 2 nanosheets induced severe mitochondrial dysfunction at sub-cytotoxic doses. Quantitative, single cell fluorescent imaging revealed mitochondrial fission and impaired mitochondrial membrane potential following MnO 2 nanosheet exposure. Seahorse analyses for cellular respiration revealed that MnO 2 nanosheets inhibited basal respiration, maximal respiration and the spare respiratory capacity of gill cells, indicating mitochondrial dysfunction and reduced cellular respiratory activity. MnO 2 nanosheet exposure also inhibited ATP production, further supporting the suppression of mitochondrial function and cellular respiration. Together, these observations indicate that 2D MnO 2 nanosheets impair the ability of gill cells to respond to energy demands or prolonged stress. Finally, our data demonstrate significant differences in the toxicity of the 2D MnO 2 nanosheets and their microparticle counterparts. This exemplifies the importance of considering the unique physical characteristics of 2D nanomaterials when conducting safety assessments.

Many layered crystal phases can be exfoliated or assembled into ultrathin 2D nanosheets with novel properties not achievable by particulate or fibrous nanoforms. Among these 2D materials are manganese dioxide (MnO 2 ) nanosheets, which have applications in batteries, catalysts, and biomedical probes. A novel feature of MnO 2 is its sensitivity to chemical reduction leading to dissolution and Mn 2+ release. Biodissolution is critical for nanosafety assessment of 2D materials, but the timing and location of MnO 2 biodissolution in environmental or occupational exposure scenarios are poorly understood. This work investigates the chemical and colloidal dynamics of MnO 2 nanosheets in biological media for environmental and human health risk assessment. MnO 2 nanosheets are insoluble in most aqueous phases, but react with strong and weak reducing agents in biological fluid environments. In vitro, reductive dissolution can be slow enough in cell culture media for MnO 2 internalization by cells in the form of intact nanosheets, which localize in vacuoles, react to deplete intracellular glutathione, and induce cytotoxicity that is likely mediated by intracellular Mn 2+ release. The results are used to classify MnO 2 nanosheets within a new hazard screening framework for 2D materials, and the implications of MnO 2 transformations for nanotoxicity testing and nanosafety assessment are discussed., (© 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Two-dimensional (2D) materials are a broad class of synthetic ultra-thin sheet-like solids whose rapid pace of development motivates systematic study of their biological effects and safe design. A challenge for this effort is the large number of new materials and their chemical diversity. Recent work suggests that many 2D materials will be thermodynamically unstable and thus non-persistent in biological environments. Such information could inform and accelerate safety assessment, but experimental data to confirm the thermodynamic predictions is lacking. Here we propose a framework for early hazard screening of nanosheet materials based on biodissolution studies in reactive media, specially chosen for each material to match chemically feasible degradation pathways. Simple dissolution and in vitro tests allow grouping of nanosheet materials into four classes: A, potentially biopersistent; B: slowly degradable (>24-48 hours); C, biosoluble with potentially hazardous degradation products; and D, biosoluble with low-hazard degradation products. The proposed framework is demonstrated through an experimental case study on MoO 3 nanoribbons, which have a dual 2D / 1D morphology and have been reported to be stable in aqueous stock solutions. The nanoribbons are shown to undergo rapid dissolution in biological simulant fluids and in cell culture, where they elicit no adverse responses up to 100μg ml -1 dose. These results place MoO 3 nanoribbons in Class D, and assigns them a low priority for further nanotoxicology testing. We anticipate use of this framework could accelerate the risk assessment for the large set of new powdered 2D nanosheet materials, and promote their safe design and commercialization.

The increasing use of silver nanoparticles (AgNPs) in consumer products raises concerns regarding the environmental exposure and impact of AgNPs on natural aquatic environments. Here, we investigated the effects of environmentally relevant AgNP concentrations on the natural plankton communities using in situ enclosures. Using twelve lake enclosures, we tested the hypotheses that AgNP concentration, dosing regimen, and capping agent (poly-vinyl pyrrolidone (PVP) vs. citrate) exhibit differential effects on plankton communities. Each of the following six treatments was replicated twice: control (no AgNPs added), low, medium, and high chronic PVP treatments (PVP-capped AgNPs added continuously, with target nominal concentrations of 4, 16, and 64 μg/L, respectively), citrate treatment (citrate-capped AgNPs added continuously, target nominal concentrations of 64 μg/L), and pulse treatment (64 μg/L PVP-AgNPs added as a single dose). Although Ag accumulated in the phytoplankton, no statistically significant treatment effect was found on phytoplankton community structure or biomass. In contrast, as AgNP exposure rate increased, zooplankton abundance generally increased while biomass and species richness declined. We also observed a shift in the size structure of zooplankton communities in the chronic AgNP treatments. In the pulse treatments, zooplankton abundance and biomass were reduced suggesting short periods of high AgNP concentrations affect zooplankton communities differently than chronic exposures. We found no evidence that capping agent affected AgNP toxicity on either community. Overall, our study demonstrates variable AgNP toxicity between trophic levels with stronger AgNP effects on zooplankton. Such effects on zooplankton are troubling and indicate that AgNP contamination could affect aquatic food webs.

Many lung cancer risk prediction models have been published but there has been no systematic review or comprehensive assessment of these models to assess how they could be used in screening. We performed a systematic review of lung cancer prediction models and identified 31 articles that related to 25 distinct models, of which 11 considered epidemiological factors only and did not require a clinical input. Another 11 articles focused on models that required a clinical assessment such as a blood test or scan, and 8 articles considered the 2-stage clonal expansion model. More of the epidemiological models had been externally validated than the more recent clinical assessment models. There was varying discrimination, the ability of a model to distinguish between cases and controls, with an area under the curve between 0.57 and 0.879 and calibration, the model's ability to assign an accurate probability to an individual. In our review we found that further validation studies need to be considered; especially for the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial 2012 Model Version (PLCOM2012) and Hoggart models, which recorded the best overall performance. Future studies will need to focus on prediction rules, such as optimal risk thresholds, for models for selective screening trials. Only 3 validation studies considered prediction rules when validating the models and overall the models were validated using varied tests in distinct populations, which made direct comparisons difficult. To improve this, multiple models need to be tested on the same data set with considerations for sensitivity, specificity, model accuracy, and positive predictive values at the optimal risk thresholds., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Expanded use of engineered nanoparticles (ENPs) in consumer products increases the potential for environmental release and unintended biological exposures. As a result, measurement techniques are needed to accurately quantify ENP size, mass, and particle number distributions in biological matrices. This work combines single particle inductively coupled plasma mass spectrometry (spICPMS) with tissue extraction to quantify and characterize metallic ENPs in environmentally relevant biological tissues for the first time. ENPs were extracted from tissues via alkaline digestion using tetramethylammonium hydroxide (TMAH). Method development was performed using ground beef and was verified in Daphnia magna and Lumbriculus variegatus . ENPs investigated include 100 and 60 nm Au and Ag stabilized by polyvynylpyrrolidone (PVP). Mass- and number-based recovery of spiked Au and Ag ENPs was high (83-121%) from all tissues tested. Additional experiments suggested ENP mixtures (60 and 100 nm Ag ENPs) could be extracted and quantitatively analyzed. Biological exposures were also conducted to verify the applicability of the method for aquatic organisms. Size distributions and particle number concentrations were determined for ENPs extracted from D. magna exposed to 98 μg/L 100 nm Au and 4.8 μg/L 100 nm Ag ENPs. The D. magna nanoparticulate body burden for Au ENP uptake was 613 ± 230 μg/kgww, while the measured nanoparticulate body burden for D. magna exposed to Ag ENPs was 59 ± 52 μg/kgww. Notably, the particle size distributions determined from D. magna tissues suggested minimal shifts in the size distributions of ENPs accumulated, as compared to the exposure media.

As the production and applications of silver nanoparticles (AgNPs) increase, it is essential to characterize fate and effects in environmental systems. Nanosilver materials may settle from suspension; therefore, the authors' objective was to utilize environmentally relevant bioassays and study the impact, bioaccumulation, tissue distribution, uptake, and depuration of AgNPs on a sediment-dwelling invertebrate, Lumbriculus variegatus. Hydrodynamic diameters of uncoated 30-nm, 80-nm, and 1500-nm AgNP powders and a polyvinyl pyrrolidone (PVP) AgNP suspension were measured utilizing dynamic light scattering in freshwater media (0-280 µS/cm). Aggregation for 30 nm, 80 nm, and 1500 nm silver increased with conductivity but was minimal for PVP silver. Lumbriculus variegatus were exposed to AgNPs or silver nitrate (AgNO3 ) spiked into sediment (nominally 100 mg/kg) and water (PVP 30 nm and 70 nm Ag, nominally 5 mg/L). Uptake was assessed through inductively coupled plasma mass spectroscopy (ICP-MS) and hyperspectral imaging. Particle sizes were examined through field flow fractionation-ICP-MS (FFF-ICP-MS) and ICP-MS in single particle mode (SP-ICP-MS). Lumbriculus variegatus were also depurated for 6 h, 8 h, 24 h, and 48 h to determine gut clearance. Bioaccumulation factors of sediment-exposed L. variegatus were similar regardless of particle size or coatings. The FFF-ICP-MS and SP-ICP-MS detected AgNPs for up to 48 h post depuration. The present study provides information on bioaccumulation and interactions of AgNPs within biological systems., (Copyright © 2013 SETAC.)

Characterization of nanomaterials must include analysis of both size and chemical composition. Many analytical techniques, such as dynamic light scattering (DLS), are capable of measuring the size of suspended nanometer-sized particles, yet provide no information on the composition of the particle. While field flow fractionation (FFF) is a powerful nanoparticle sizing technique, common detectors used in conjunction with the size separation, including UV, light-scattering, and fluorescence spectroscopy, do not provide the needed particle compositional information. Further, these detectors do not respond directly to the mass concentration of nanoparticles. The present work describes the advantages achieved when interfacing sensitive and elemental specific detectors, such as inductively coupled plasma atomic emission spectroscopy and mass spectrometry, to FFF separation analysis to provide high resolution nanoparticle sizing and compositional analysis at the μg/L concentration level, a detection at least 10-100-fold lower than DLS or FFF-UV techniques. The full benefits are only achieved by utilization of all detector capabilities, such as dynamic reaction cell (DRC) ICP-MS. Such low-level detection and characterization capability is critical to nanomaterial investigations at biologically and environmentally relevant concentrations. The techniques have been modified and applied to characterization of all four elemental constituents of cadmium selenide-zinc sulfide core-shell quantum dots, and silver nanoparticles with gold seed cores. Additionally, sulfide coatings on silver nanoparticles can be detected as a potential means to determine environmental aging of nanoparticles., (Published by Elsevier B.V.)

Sizing engineered nanoparticles in simple, laboratory systems is now a robust field of science; however, application of available techniques to more complex, natural systems is hindered by numerous challenges including low nanoparticle number concentrations, polydispersity from aggregation and/or dissolution, and interference from other incidental particulates. A new emerging technique, single particle inductively coupled plasma-mass spectrometry (spICPMS), has the potential to address many of these analytical challenges when sizing inorganic nanoparticles in environmental matrices. However, to date, there is little beyond the initial feasibility studies that investigates the performance characteristics and validation of spICPMS as a nanoparticle sizing technique. This study compares sizing of four silver nanoparticle dispersions (nominal diameters of 40, 60, 80, and 100 nm) by spICPMS to four established sizing techniques: dynamic light scattering, differential centrifugal sedimentation, nanoparticle tracking analysis, and TEM. Results show that spICPMS is able to size silver nanoparticles, across different sizes and particle number concentrations, with accuracy similar to the other commercially available techniques. Furthermore, a novel approach to evaluating particle coincidence is presented. In addition, spICPMS size measurements were successfully performed on nanoparticles suspended in algal growth media at low concentrations. Overall, while further development of the technique is needed, spICPMS yields important advantages over other techniques when sizing nanoparticles in environmentally relevant media.

Deficits in temporal processing are implicated in Attention Deficit Hyperactivity Disorder (ADHD) for which the most common rodent model is the Spontaneously Hypertensive Rat (SHR). To assess strain differences in temporal processing, males and females of the SHR, Wistar-Kyoto (WKY), and Sprague-Dawley (SD) strains were compared on two timing tasks: one requiring maintenance of a lever press for 10-14 s (TRD, temporal response differentiation) and the other requiring withholding of a lever press for 10-14 s (DRL, differential reinforcement of low rates). Performance of the progressive ratio (PR) task more directly assessed food-motivated behavior. Strains did not differ in task acquisition; however, steady state TRD and DRL performance of the SHR and WKY strains was less accurate which was related to increased burst (non-timing related) responses in those strains relative to the SD. PR performance demonstrated that the SHR and WKY strains exhibited higher response rates and breakpoints than the SD. Subsequently, methylphenidate (1, 3.25, 4.50, 7.50, and 12.0 mg/kg) and d-amphetamine (0.1, 0.25, 0.65, 1.0, and 2.0 mg/kg) were administered intraperitoneally pre-testing. Both drugs disrupted TRD and DRL performances by increasing burst response frequency; however, the strains were not differentially sensitive to either drug. Strain differences were generally maintained throughout the drug and extinction portions of the study. These results indicate increased similarity between the SHR and WKY strains relative to the SD in performance of timing and motivation tasks. Further, the current results do not support continued use of the SHR as a model for ADHD.

Male and female spontaneously hypertensive (SHR), Wistar-Kyoto (WKY), and Sprague-Dawley (SD) rats were assessed at one of two ages (postnatal day 74 or 346) for open field locomotor activity and anxiety-related behavior in the elevated plus maze (EPM). In general, the SHR displayed the least anxiety-related behavior, an effect that was magnified with age. At 11 months of age, the SHR more frequently entered and remained longer in the open arms than either the SD or the WKY strains. EPM behavior of the WKY strain was much less affected by age than that of the SD strain which displayed increased anxiety-related behavior with age. At the younger age, the typical sex effects were apparent; specifically, females exhibited a shorter duration in the closed arms. While the SHR were the most active strain in the EPM at both ages, they were more active in the open field only at the older age. In general, age-related changes in open field activity mirrored those of the EPM. These results provide a more comprehensive illustration of aging-related behavioral changes in male and female SHR, WKY and SD rats.

The spontaneously hypertensive rat (SHR) is often used as a model for childhood attention-deficit/hyperactivity disorder (ADHD). To investigate behavioral maturation in SHR, body weight, age at eye opening, and performance in several behavioral tasks in male and female SHR, Wistar-Kyoto (WKY), and Sprague-Dawley rats were compared. SHRs were slower in performing the righting reflex on PND 4 and negative geotaxis compared with WKY and Sprague-Dawley. Both SHR and WKY were delayed relative to Sprague-Dawley in eye opening and beam walking. Rotarod performance was comparable in the 3 strains. Males were faster to right themselves than females, but there were no other significant sex differences nor Sex X Strain interactions. Delayed development in SHR may be related to a maturational delay observed in children with ADHD. Research assessing early behaviors in SHR, WKY, and other strains will help determine the most appropriate model for childhood ADHD and may help predict later behavioral dysfunction.

The cerebellum is critically involved in temporal processes in the millisecond range and may be involved in longer time estimations (i.e. in the seconds range). Estimates in the millisecond range are impaired after developmentally induced cerebellar alterations, however, little is known about the effects of similar alterations on longer timing performance. Appropriately timed DFMO treatment reliably causes cerebellar stunting in rats, however, its effects on temporal estimation performance are unknown. Here, male and female Sprague-Dawley rats were treated with subcutaneous injections of 500 mg/kg DFMO on postnatal days 5-12, causing a 10% cerebellar weight reduction at adulthood. As adults, subjects were tested under one of two paradigms - a differential reinforcement of low response rate (DRL) task requiring that subjects withhold a lever press response for 10-14 s or a temporal response differentiation (TRD) task requiring that subjects maintain a lever press response for 10-14 s. Training and steady-state performance of the DRL and TRD tasks were not significantly altered by DFMO treatment. Performance after acute challenges with two dopaminergic agonists (2.00-7.50 mg/kg methylphenidate and 0.10-1.00 mg/kg d-amphetamine) was measured after which all subjects underwent behavioral extinction. Generally, performance after methylphenidate and d-amphetamine was similar in control and DFMO-treated rats and DFMO treatment had no differential effects on performance during extinction. These results support findings from an earlier study [Ferguson SA, Paule MG, Holson RR. Neonatal dexamethasoneon day 7 in rats causes behavioral alterations reflective of hippocampal, but not cerebellar, deficits. Neurotoxicol Teratol, 2001; 23:57-69] indicating that developmental cerebellar stunting has few effects on time estimation within the range of seconds.

Postnatal treatment with alpha-difluoromethylornithine (DFMO), a potent inhibitor of ornithine decarboxylase, reduces polyamine levels in rats. Because polyamines are critically involved in growth and development, body and/or brain weights are often decreased by DFMO treatment. Here, rats were injected subcutaneously with 0, 250, 500, or 750 mg/kg of DFMO on postnatal days (PNDs) 5-10. Behavioral assessments included righting reflex, negative geotaxis, forelimb hanging, open field activity, and rotarod performance. Additionally, day of eye opening was recorded and on PND 28, whole and regional brain weights were measured. Cerebellar/whole-brain ratio was decreased in a dose-dependent manner whereas frontal cortex/whole-brain ratio was increased. Eye opening was delayed to a similar extent in all treated groups whereas body weight was unaffected. alpha-difluoromethylornithine treatment had no significant effects on the assessed behaviors. These results indicate that 6 days of DFMO treatment can substantially impact cerebellar development, but this appears to have few effects on these early assessed behaviors. However, potential behavioral alterations may not be apparent until adulthood. Published by Elsevier Science Inc.