Unveiling Local Aging Patterns Following Accelerated Stress Testing of High-Performance Polymer Electrolyte Fuel Cells.

This study presents an in-depth analysis of heterogeneous aging patterns in membrane electrode assemblies (MEAs) subjected to diverse accelerated stress test (AST) conditions, simulating carbon corrosion (CC AST) and Pt particle size growth in fully humidified (Pt AST-Wet) and underhumidified (Pt AST-Dry) H2/N2 atmospheres. Multimodal characterization techniques are used to focus on heterogeneous aging patterns, primarily examining the variations in current distributions and Pt particle size maps. The findings reveal distinct characteristics of current distributions for all the AST cases, with substantial changes and strong current gradients in the CC AST case, indicative of severe performance degradation. Notably, despite significant differences in Pt particle size growth at the end-of-life (EOL), the Pt AST-Wet and Pt AST-Dry cases show minor changes in spatial current distributions. Moreover, a preferential growth of Pt particles under serpentine flow field bends in the Pt AST-Wet case is observed for the first time. This study provides crucial insights into the role of mass transport properties in shaping fuel cell performance, and highlights the need to consider factors beyond electrochemically-active surface area (ECSA) when assessing fuel cell durability.

Predictors of Responsivity to Interdisciplinary Pain Management.

Objective: This study investigated for whom interdisciplinary pain management (IPM) is most effective. Identification of predictors of treatment responsivity would facilitate development of patient-treatment matching algorithms to optimize outcomes. Design: Repeated measures prospective study of consecutive admissions to a two-week IPM program. Setting: Brisbane Pain Rehabilitation Service in Brisbane, Australia. Subjects: A total of 163 adults referred for chronic pain management. Methods: Self-report questionnaires and measures of physical performance were obtained at program entry and completion. Group-level analyses were performed using standard parametric statistics. Individual-level change was assessed using recommended criteria. Multivariate analysis of variance and logistic regression were used to examine outcomes and predictors of response. Results: Significant improvements were observed across psychological, social, and physical outcome domains. Up to 50% of participants had clinically meaningful improvements, while less than 10% deteriorated. Higher baseline depression, anxiety, stress, and pain catastrophizing scores predicted better group-level outcomes (Ps < 0.05). Participants with higher baseline depression scores were most likely to show significant individual-level improvement on at least one outcome (Ps < 0.05). Participants with nociceptive pain were more than four times more likely than those with neuropathic pain to show clinically meaningful improvement on multiple outcomes, while those participants who were older were more likely to be multidomain responders. Conclusions: Physical, psychological, and social outcomes all improved in a significant proportion of participants following the IPM. High baseline depression was a clinically reliable predictor of individual-level improvement. Individuals with nociceptive pain and those who were older, respectively, showed the largest response across multiple outcomes and domains.

Promotion of myofibroblast differentiation through repeated treatment of fibroblasts to low concentrations of PM2.5.

Exposure to particulate matter ≤ 2.5 µm (PM2.5) is a risk factor for many lung diseases. Although the toxicologic effects of PM2.5 on airway epithelium are well-described, the effects of PM2.5 on fibroblasts in the lung are less studied. Here, we sought to examine the effects of PM2.5 on the differentiation of fibroblasts into myofibroblasts. Although a single treatment of fibroblasts did not result in a change in collagen or the myofibroblast marker α-SMA, exposing fibroblasts to sequential treatments with PM2.5 at low concentrations caused a robust increase in these proteins. Treatment of fibroblasts with IMD0354, an inhibitor to nuclear factor κB, but not with an antagonist to aryl hydrocarbon receptor, abolished the ability of PM2.5 to induce myofibroblast differentiation. These data demonstrate that potential impact of PM2.5 to fibroblast activation and fibrosis and support the importance of utilizing low concentrations and varying exposure protocols to toxicologic studies.

Early evidence for complex social structure in Proboscidea from a late Miocene trackway site in the United Arab Emirates.

Many living vertebrates exhibit complex social structures, evidence for the antiquity of which is limited to rare and exceptional fossil finds. Living elephants possess a characteristic social structure that is sex-segregated and multi-tiered, centred around a matriarchal family and solitary or loosely associated groups of adult males. Although the fossil record of Proboscidea is extensive, the origin and evolution of social structure in this clade is virtually unknown. Here, we present imagery and analyses of an extensive late Miocene fossil trackway site from the United Arab Emirates. The site of Mleisa 1 preserves exceptionally long trackways of a herd of at least 13 individuals of varying size transected by that of a single large individual, indicating the presence of both herding and solitary social modes. Trackway stride lengths and resulting body mass estimates indicate that the solitary individual was also the largest and therefore most likely a male. Sexual determination for the herd is equivocal, but the body size profile and number of individuals are commensurate with those of a modern elephant family unit. The Mleisa 1 trackways provide direct evidence for the antiquity of characteristic and complex social structure in Proboscidea.

Four-thousand-year-old gold artifacts from the Lake Titicaca basin, southern Peru.

Artifacts of cold-hammered native gold have been discovered in a secure and undisturbed Terminal Archaic burial context at Jiskairumoko, a multicomponent Late Archaic-Early Formative period site in the southwestern Lake Titicaca basin, Peru. The burial dates to 3776 to 3690 carbon-14 years before the present (2155 to 1936 calendar years B.C.), making this the earliest worked gold recovered to date not only from the Andes, but from the Americas as well. This discovery lends support to the hypothesis that the earliest metalworking in the Andes was experimentation with native gold. The presence of gold in a society of low-level food producers undergoing social and economic transformations coincident with the onset of sedentary life is an indicator of possible early social inequality and aggrandizing behavior and further shows that hereditary elites and a societal capacity to create significant agricultural surpluses are not requisite for the emergence of metalworking traditions.

Effect of concentration and duration of particulate matter exposure on the transcriptome and DNA methylome of bronchial epithelial cells.

Exposure to particulate matter (PM) from ambient air pollution is a well-known risk factor for many lung diseases, but the mechanism(s) for this is not completely understood. Bronchial epithelial cells, which line the airway of the respiratory tract, undergo genome-wide level changes in gene expression and DNA methylation particularly when exposed to fine (<2.5 µm) PM (PM2.5). Although some of these changes have been reported in other studies, a comparison of how different concentrations and duration of exposure affect both the gene transcriptome and DNA methylome has not been done. Here, we exposed BEAS-2B, a bronchial epithelial cell line, to different concentrations of PM2.5, and compared how single or repeated doses of PM2.5 affect both the transcriptome and methylome of cells. Widespread changes in gene expression occurred after cells were exposed to a single treatment of high-concentration (30 µg/cm2) PM2.5 for 24 h. These genes were enriched in pathways regulating cytokine-cytokine interactions, Mitogen-Activated Protein Kinase (MAPK) signaling, PI3K-Akt signaling, IL6, and P53. DNA methylomic analysis showed that nearly half of the differentially expressed genes were found to also have DNA methylation changes, with just a slightly greater trend toward overall hypomethylation across the genome. Cells exposed to a lower concentration (1 µg/cm2) of PM2.5 demonstrated a comparable, but more attenuated change in gene expression compared to cells exposed to higher concentrations. There were also many genes affected by lower concentrations of PM2.5, but not higher concentrations. Additionally, repeated exposure to PM2.5 (1 µg/cm2) for seven days resulted in transcriptomic and DNA methylomic changes that were distinct from cells treated with PM2.5 for only one day. Compared to single exposure, repeated exposure to PM2.5 caused a more notable degree of hypomethylation across the genome, though certain genes and regions demonstrated increased DNA methylation. The overall increase in hypomethylation, especially with repeated exposure to PM2.5, was associated with an increase in expression of ten-eleven translocation enzymes. These data demonstrate how variations in concentration and duration of PM2.5 exposure induce distinct differences in the transcriptomic and DNA methylomic profile of bronchial epithelial cells, which may have important implications in the development of both acute and chronic lung disease.