Publications by authors named "Stewart Katherine"

A key challenge in the development of organic mixed ionic-electronic conducting materials (OMIEC) for high performance electrochemical transistors is their stable performance in ambient. When operating in aqueous electrolyte, potential reactions of the electrochemically injected electrons with air and water could hinder their persistence, leading to a reduction in charge transport. Here, the impact of deepening the LUMO energy level of a series of electron-transporting semiconducting polymers is evaluated, and subsequently rendering the most common oxidation processes of electron polarons thermodynamically unfavorable, on organic electrochemical transistors (OECTs) performance.

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Billions of cells are eliminated daily from our bodies. Although macrophages and dendritic cells are dedicated to migrating and engulfing dying cells and debris, many epithelial and mesenchymal tissue cells can digest nearby apoptotic corpses. How these non-motile, non-professional phagocytes sense and eliminate dying cells while maintaining their normal tissue functions is unclear.

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Glycol sidechains are often used to enhance the performance of organic photoconversion and electrochemical devices. Herein, we study their effects on electronic states and electronic properties. We find that polymer glycolation not only induces more disordered packing, but also results in a higher reorganisation energy due to more localised π-electron density.

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Article Synopsis
  • When skin gets hurt, special cells called hair follicle stem cells (HFSCs) move to help heal the wound but face tough inflammation.
  • These HFSCs activate certain proteins that help protect them and support healing, like CD80.
  • If HFSCs can’t use CD80, healing gets worse because they can’t call for help from other immune cells, which makes it harder for the skin to get better.
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Lineage plasticity-a state of dual fate expression-is required to release stem cells from their niche constraints and redirect them to tissue compartments where they are most needed. In this work, we found that without resolving lineage plasticity, skin stem cells cannot effectively generate each lineage in vitro nor regrow hair and repair wounded epidermis in vivo. A small-molecule screen unearthed retinoic acid as a critical regulator.

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Polyaniline (PANI) and two copolymers, poly(aniline---toluidine) (PoTOL-50) and poly(aniline---anisidine) (PoANI-50) were synthesized with equal input ratios (1:1) to enhance PANI as sensing material for the sensing of various heavy metal analytes in aqueous solutions. The polymers were evaluated for both their sensitivity and selectivity toward four heavy metals (Ba, Cd, Cu, and Ni) and two common matrix interferents (Ca and Mg) at 10 and 40 ppm. The effect of pH and ionic strength of the aqueous solutions on the sensitivity and selectivity was also evaluated.

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Polarons exist when charges are injected into organic semiconductors due to their strong coupling with the lattice phonons, significantly affecting electronic charge-transport properties. Understanding the formation and (de)localization of polarons is therefore critical for further developing organic semiconductors as a future electronics platform. However, there are very few studies reported in this area.

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Macrophages and dendritic cells have long been appreciated for their ability to migrate to and engulf dying cells and debris, including some of the billions of cells that are naturally eliminated from our body daily. However, a substantial number of these dying cells are cleared by 'non-professional phagocytes', local epithelial cells that are critical to organismal fitness. How non-professional phagocytes sense and digest nearby apoptotic corpses while still performing their normal tissue functions is unclear.

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Soil invertebrates are an integral part of Arctic ecosystems through their roles in the breakdown of litter, soil formation, and nutrient cycling. However, studies examining soil invertebrates in the Arctic are limited and our understanding of the abiotic and biotic drivers of these invertebrate communities remains understudied. We examined differences in soil invertebrate taxa (mites, collembolans, enchytraeids) among several undisturbed upland tundra heath sites in Nunavut Canada and identified the drivers (vegetation and substrate cover, soil nutrients and pH) of the soil invertebrate community across these sites.

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Edge effects resulting from adjacent land uses are poorly understood in agroecosystems yet understanding above and belowground edge effects is crucial for maintaining ecosystem function. The aim of our study was to examine impacts of land management on aboveground and belowground edge effects, measured by changes in plant community, soil properties, and soil microbial communities across agroecosystem edges. We measured plant composition and biomass, soil properties (total carbon, total nitrogen, pH, nitrate, and ammonium), and soil fungal and bacterial community composition across perennial grassland-annual cropland edges.

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As a growing number of states legalize the use of cannabinoids for medical and non-medical purposes, there continues to be large gaps in the understanding of appropriate dosing, impact on health, and the state's role in regulation of products. Here, we present a summary of 2022 cannabis regulations by state to evaluate for the presence of THC:CBD ratios, maximum THC concentration or content within products, specific caps for cannabis possession, and requirements for testing for cannabinoid content and/or contaminants such as pesticides and heavy metals. These results are presented in Map 1 and Table 1 and demonstrate substantial variation among product THC content, purchasing limits, and quality measurements across the country.

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Background: Occupational science and occupational therapy typically perceive occupations as promoting health and well-being. However, this perspective overlooks the many occupations that are viewed as illegal, unhealthy, or risky, such as drug use. Due to its negative association with health, drug use is perceived as not holding significance or meaning in people's lives.

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Squamous cell carcinomas are triggered by marked elevation of RAS-MAPK signalling and progression from benign papilloma to invasive malignancy. At tumour-stromal interfaces, a subset of tumour-initiating progenitors, the cancer stem cells, obtain increased resistance to chemotherapy and immunotherapy along this pathway. The distribution and changes in cancer stem cells during progression from a benign state to invasive squamous cell carcinoma remain unclear.

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Metal-impacted sites often need aggressive ecorestoration strategies to restore a functional plant-soil system. The use of biological soil crusts for soil stabilization, moisture retention and C and N input in disturbed and contaminated soils is becoming a more common ecorestoration practice. Biological soil crusts comprise cyanobacteria, fungi, lichens, and bryophytes (mostly moss).

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Aim: Myocardial infarction remains the leading cause of heart failure. The adult human heart lacks the capacity to undergo endogenous regeneration. New blood vessel growth is integral to regenerative medicine necessitating a comprehensive understanding of the pathways that regulate vascular regeneration.

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The indirect effects of herbicides on habitat quality in boreal ecoregions remain poorly understood. Herbicides are commonly applied on boreal rights-of-way to control vegetation below power lines, where they can indirectly enter the soil ecosystem after leaf abscission. Key soil processes such as litter decomposition and soil nutrient cycling can be influenced by altering litter chemistry and/or impacting decomposer species.

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Purpose Of Review: Sentinel lymph node (SLN) mapping has been adopted as an acceptable method of lymph node evaluation in the surgical staging for low-grade endometrial cancer. In this review, we analyze the literature on the utility of SLN mapping in high-grade endometrial cancer.

Recent Findings: SLN mapping in high-grade endometrial cancer demonstrates similar high detection rates and diagnostic accuracy as seen in low-grade endometrial cancers.

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Semiconducting polymers with oligoethylene glycol (OEG) sidechains have attracted strong research interest for organic electrochemical transistor (OECT) applications. However, key molecular design rules for high-performance OECTs via efficient mixed electronic/ionic charge transport are still unclear. In this work, new glycolated copolymers (gDPP-TTT and gDPP-TTVTT) with diketopyrrolopyrrole (DPP) acceptor and thiophene (T) and vinylene (V) thiophene-based donor units are synthesized and characterized for accumulation mode OECTs, where a long-alkyl-group (C ) attached to the DPP unit acts as a spacer distancing the OEG groups from the polymer backbone.

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Aims: Endothelial cell (EC) dysfunction drives the initiation and pathogenesis of pulmonary arterial hypertension (PAH). We aimed to characterize EC dynamics in PAH at single-cell resolution.

Methods And Results: We carried out single-cell RNA sequencing (scRNA-seq) of lung ECs isolated from an EC lineage-tracing mouse model in Control and SU5416/hypoxia-induced PAH conditions.

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Objective: A sentinel lymph node biopsy is widely accepted as the standard of care for surgical staging in low-grade endometrial cancer, but its value in high-grade endometrial cancer remains controversial. The aim of this systematic review and meta-analysis was to evaluate the performance characteristics of sentinel lymph node biopsy in patients with endometrial cancer with high-grade histology (registered in the International Prospective Register of Systematic Reviews with identifying number CRD42020160280).

Data Sources: We systematically searched the MEDLINE, Epub Ahead of Print, MEDLINE In-Process & Other Non-Indexed Citations, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and Embase databases all through the OvidSP platform.

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Objectives: To evaluate the ability of pathology modules to promote learning of pathology-related course content in a preclinical medical education curriculum.

Methods: Pathology modules were created for the "Hematology/Oncology" and "Women's Health" (WH) courses. Students were recruited over 2 consecutive academic years; cohorts 1 and 2 refer to 2 separate groups of students in years 1 and 2, respectively, of the study.

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Indigenous nations worldwide are working with and lobbying private and public resource developers to ensure meaningful engagement in decisions tied to resource development in their territories. The diversity of approaches for engagement can be framed along a continuum, with voluntary practices at one end and legal responsibilities at the other. Given this continuum, the roles and responsibilities of various actors involved have become blurred, which leads to poor practice.

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Herbicide use on boreal transmission line rights-of-way has been relatively limited compared to more temperate regions and therefore challenges exist in estimating and communicating the associated risks. Herbicides directly enter the ecosystem through deposition on vegetation and soils and can be a vector of contamination to browsing herbivores. Triclopyr drift and foliage concentrations were quantified following basal bark (Garlon RTU) and low-volume foliar (Garlon XRT) field treatments to aspen (Populus tremuloides) saplings and willow (Salix bebbiana) shrubs, respectively.

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Through recurrent bouts synchronous with the hair cycle, quiescent melanocyte stem cells (McSCs) become activated to generate proliferative progeny that differentiate into pigment-producing melanocytes. The signaling factors orchestrating these events remain incompletely understood. Here, we use single-cell RNA sequencing with comparative gene expression analysis to elucidate the transcriptional dynamics of McSCs through quiescence, activation, and melanocyte maturation.

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Fertility-sparing management of early-stage gynecologic cancers is becoming more prevalent as increasing evidence demonstrates acceptable oncologic and reproductive outcomes in appropriately selected patients. However, in the absence of randomized controlled trials, most of the commonly used treatment algorithms are based only on observational studies. As women are increasingly postponing childbearing, the need for evidence-based guidance on the optimal selection of appropriate candidates for fertility-sparing therapies is paramount.

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