2,194 results on '"Trevor K"'
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2. Prostate Cancer: A Review of Genetics, Current Biomarkers and Personalised Treatments
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Trevor K. Wilson and Oliver T. Zishiri
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biomarkers ,genes ,personalised treatment ,prostate cancer ,Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,RC254-282 - Abstract
ABSTRACT Background Prostate cancer is the second leading cause of cancer deaths in men, second only to lung cancer. Despite this, diagnosis and prognosis methods remain limited, with effective treatments being few and far between. Traditionally, prostate cancer is initially tested for through a prostate serum antigen (PSA) test and a digital rectum examination (DRE), followed by confirmation through an invasive prostate biopsy. The DRE and biopsy are uncomfortable for the patient, so less invasive, accurate diagnostic tools are needed. Current diagnostic tools, along with genes that hold possible biomarker uses in diagnosis, prognosis and indications for personalised treatment plans, were reviewed in this article. Recent Findings Several genes from multiple families have been identified as possible biomarkers for disease, including those from the MYC and ETS families, as well as several tumour suppressor genes, Androgen Receptor signalling genes and DNA repair genes. There have also been advances in diagnostic tools, including MRI‐targeted and liquid biopsies. Several personalised treatments have been developed over the years, including those that target metabolism‐driven prostate cancer or those that target inflammation‐driven cancer. Conclusion Several advances have been made in prostate cancer diagnosis and treatment, but the disease still grows year by year, leading to more and more deaths annually. This calls for even more research into this disease, allowing for better diagnosis and treatment methods and a better chance of patient survival.
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- 2024
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3. Acute depletion of BRG1 reveals its primary function as an activator of transcription
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Gang Ren, Wai Lim Ku, Guangzhe Ge, Jackson A. Hoffman, Jee Youn Kang, Qingsong Tang, Kairong Cui, Yong He, Yukun Guan, Bin Gao, Chengyu Liu, Trevor K. Archer, and Keji Zhao
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Science - Abstract
Abstract The mammalian SWI/SNF-like BAF complexes play critical roles during animal development and pathological conditions. Previous gene deletion studies and characterization of human gene mutations implicate that the complexes both repress and activate a large number of genes. However, the direct function of the complexes in cells remains largely unclear due to the relatively long-term nature of gene deletion or natural mutation. Here we generate a mouse line by knocking in the auxin-inducible degron tag (AID) to the Smarca4 gene, which encodes BRG1, the essential ATPase subunit of the BAF complexes. We show that the tagged BRG1 can be efficiently depleted by osTIR1 expression and auxin treatment for 6 to 10 h in CD4 + T cells, hepatocytes, and fibroblasts isolated from the knock-in mice. The acute depletion of BRG1 leads to decreases in nascent RNAs and RNA polymerase II binding at a large number of genes, which are positively correlated with the loss of BRG1. Further, these changes are correlated with diminished accessibility at DNase I Hypersensitive Sites (DHSs) and p300 binding. The acute BRG1 depletion results in three major patterns of nucleosome shifts leading to narrower nucleosome spacing surrounding transcription factor motifs and at enhancers and transcription start sites (TSSs), which are correlated with loss of BRG1, decreased chromatin accessibility and decreased nascent RNAs. Acute depletion of BRG1 severely compromises the Trichostatin A (TSA) -induced histone acetylation, suggesting a substantial interplay between the chromatin remodeling activity of BRG1 and histone acetylation. Our data suggest BRG1 mainly plays a direct positive role in chromatin accessibility, RNAPII binding, and nascent RNA production by regulating nucleosome positioning and facilitating transcription factor binding to their target sites.
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- 2024
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4. Molecular detection of multidrug and methicillin resistance in Staphylococcus aureus isolated from wild pigeons (Columba livia) in South Africa
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Trevor K. Wilson, Oliver T. Zishiri, and Mohamed E. El Zowalaty
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Staphylococcus aureus ,Antimicrobial resistance ,Wild pigeons ,Columba domestica livia ,Columba livia ,Houseflies ,Medicine (General) ,R5-920 - Abstract
Staphylococcus aureus is an important human and veterinary pathogen. The present study aimed to determine the prevalence of antibiotic resistance among S. aureus isolated from samples obtained from free-flying wild pigeons and houseflies from different locations surrounding a local hospital in the Greater Durban area in KwaZulu-Natal Province, South Africa. Environmental fecal samples were obtained from wild pigeons that inhabits the grounds of a local public hospital located on the South Beach area, Durban, South Africa. Housefly samples were collected from three different locations (Kenneth Stainbank Nature Reserve, Montclair/Clairwood, and Glenwood/Berea) in the greater Durban area, all within a close proximity to the hospital. Following enrichment, identification, and antimicrobial resistance profiling, S. aureus isolates were subjected to DNA extraction using the boiling method. It was found that 57 out of 252 samples (22.62%) were positive for S. aureus. The Kirby-Bauer disk diffusion method of antibiotic susceptibility testing was performed and revealed that antibiotic resistance rates to penicillin and rifampicin were the most common, with both returning 48 (84.2%) out of the 57 S. aureus isolates being resistant to penicillin and rifampicin. Antibiotic resistance rates to clindamycin, linezolid, erythromycin, tetracycline, cefoxitin, and ciprofloxacin were 82.5%, 78.9%, 73.7%, 63.2%, 33.3%, and 15.8% respectively. Antibiotic resistance genes were detected using primer-specific PCR and it was found that the prevalence rates of tetM, aac(6′)–aph(2″), mecA, tetK, ermc, and blaZ genes were 66.7%, 40.4%, 40.4%, 38.6%, 24.6%, and 3.51% respectively. Statistical analysis revealed significant (p
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- 2024
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5. Molecular detection of virulence genes in Staphylococcus aureus isolated from wild pigeons (Columba domestica livia) in KwaZulu-Natal in South Africa
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Trevor K. Wilson, Oliver T. Zishiri, and Mohamed E. El Zowalaty
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Staphylococcus aureus ,Virulence genes ,Hospital ,LukS/F-PV ,Hla ,Hld ,Medicine (General) ,R5-920 - Abstract
The current study aimed to determine virulence determinants among S. aureus isolated from wild pigeons and houseflies around hospital areas in the Greater Durban area, South Africa. Following enrichment and bacterial growth, DNA extraction using the boiling method was performed. Overall, 57 out of 252 samples (22.6%) were positive for S. aureus. Six known virulence genes were tested, where five known virulence determinants were positive and none of the S. aureus isolates were positive to coagulase (coa) gene. The highest prevalence rates were found in the genes encoding haemolysins, with the hla and hld genes having 8 (14%) and 9 (15.8%) positive isolates respectively. The sea, LukS/F-PV, and spa genes had 5 (8.8%), 4 (7%), and 2 (3.5%) positive isolates respectively. These results demonstrated the detection of pathogenic S. aureus from hospital environment in Durban, South Africa which may account for the emergence staphylococcal infections. The findings of the present study highlights the significant role of wild pigeons and houseflies as potenital infectious disease vectors in a One Health context.
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- 2024
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6. MRGPRX2 antagonist GE1111 attenuated DNFB-induced atopic dermatitis in mice by reducing inflammatory cytokines and restoring skin integrity
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Trevor K. Wong, Ye Gi Choi, Philip H. Li, Billy K. C. Chow, and Mukesh Kumar
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MRGPRX2 ,atopic dermatitis ,eczema ,allergy ,inflammation ,small molecule antagonist ,Immunologic diseases. Allergy ,RC581-607 - Abstract
IntroductionAtopic dermatitis (AD) is a chronic inflammatory skin disorder characterised by itching, erythema, and epidermal barrier dysfunction. The pathogenesis of AD is complex and multifactorial; however,mast cell (MC) activation has been reported to be one of the crucial mechanisms in the pathogenesis of AD. The MC receptor Mas related G protein-coupled receptor-X2 (MRGPRX2) has been identified as a prominent alternative receptor to the IgE receptor in causing MC activation and the subsequent release of inflammatory mediators. The current study aimed to evaluate the therapeutic effect of a novel small molecule MRGPRX2 antagonist GE1111 in AD using in vitro and in vivo approaches. MethodsWe developed an in vitro cell culture disease model by using LAD-2 MC, HaCaT keratinocytes and RAW 264.7 macrophage cell lines. We challenged keratinocytes and macrophage cells with CST-14 treated MC supernatant in the presence and absence of GE1111 and measured the expression of tight junction protein claudin 1, inflammatory cytokines and macrophage phagocytosis activity through immunohistochemistry, western blotting, RT-qPCR and fluorescence imaging techniques. In addition to this, we developed a DFNB-induced AD model in mice and evaluated the protective effect and underlying mechanism of GE1111.Results and DiscussionOur in vitro findings demonstrated a potential therapeutic effect of GE1111, which inhibits the expression of TSLP, IL-13, MCP-1, TNF-a, and IL-1ß in MC and keratinocytes. In addition to this, GE1111 was able to preserve the expression of claudin 1 in keratinocytes and the phagocytotic activity of macrophage cells. The in vivo results demonstrated that GE1111 treatment significantly reduced phenotypic changes associated with AD (skin thickening, scaling, erythema and epidermal thickness). Furthermore, immunohistochemical analysis demonstrated that GE1111 treatment preserved the expression of the tight junction protein Involucrin and reduced the expression of the inflammatory mediator periostin in the mouse model of AD. These findings were supported by gene and protein expression analysis, where GE1111 treatment reduced the expression of TSLP, IL-13, and IL-1ß, as well as downstream signalling pathways of MRGPRX2 in AD skin lesions. In conclusion, our findings provide compelling in vitro and in vivo evidence supporting the contribution of MRGPRX2-MC interaction with keratinocytes and macrophages in the pathogenesis of AD.
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- 2024
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7. Defining the biosecurity risk posed by soil found on sea freight
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Mark R. McNeill, Craig B. Phillips, Nicola K. Richards, Lee T. Aalders, Chikako van Koten, Trevor K. James, Sandra D. Young, Nigel L. Bell, and Aurelie Laugraud
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Biology (General) ,QH301-705.5 - Abstract
Soil associated with sea freight (shipping containers, flat racks and used machinery) arriving at New Zealand seaports was sampled for bacteria, fungi, nematodes, macro-invertebrates and plant seeds. Pseudomonads were selectively isolated, as several significant plant pathogens fall within this bacterial group. The mean and median sample weight collected from sea freight was found to be 417.3 and 152.7 g, respectively, with most recovered soil (73%) collected from the underside of shipping containers and flat rack containers. Likewise, for used machinery, most recovered soil (75%) was found under the machinery. Flat rack containers had significantly higher soil contamination compared to shipping containers and used machinery, but generally the counts and incidence of taxa were significantly lower compared to these other freight types. Viable bacteria, fungi, nematodes, seeds and arthropods were associated with the soil, with both counts g-1 and prevalence in samples varying with taxa, freight type, and location on the freight. Various regulated biosecurity organisms were recovered from the samples, including Aphelenchoides besseyi (rice white tip nematode), and seeds from genera such as Brachiaria, Cortaderia, Digitaria, Eragrostis and Sonchus. There were also live arthropod taxa that were not recorded as being present in New Zealand. No known plant pathogenic pseudomonads were identified through sequencing of the 16S ribosomal RNA gene. Shipping containers were found to be an important introduction pathway for exotic species, and therefore require careful monitoring and management. Comparisons of the incidence and mean number of organisms associated with soil on sea freight compared to a previous study with soil on footwear, generally showed that incidence and counts of many taxa were lower on sea freight, indicating that biosecurity risk can vary with pathway. However, prioritising one soil pathway over another according to the risks they present, and differentially allocating resources is problematic because the relative risk is dynamic, dictated by factors such as new pests or diseases entering the respective pathways.
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- 2023
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8. A first survey for herbicide resistant weeds across major maize growing areas in the North Island of New Zealand.
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Zachary Ngow, Trevor K James, Ben Harvey, and Christopher E Buddenhagen
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Medicine ,Science - Abstract
Weeds are increasingly documented with evolved resistance to herbicides globally. Three species have been reported as resistant in maize crops in New Zealand: Chenopodium album to atrazine and dicamba, Persicaria maculosa to atrazine and Digitaria sanguinalis to nicosulfuron. Despite knowledge of these cases, the distribution of these resistant biotypes is unknown. This study aimed to determine the prevalence of known resistant weeds in major maize growing areas in New Zealand, and to pro-actively screen other species for resistance. Weed seeds of broadleaf and grass species were collected from 70 randomly selected maize growing farms in the North Island in 2021-2022. Seeds were grown and treated with herbicides at recommended field rates. Atrazine-resistant C. album were recorded in a third of surveyed farms and nicosulfuron-resistant D. sanguinalis in a sixth. Half of Waikato farms and a quarter of Bay of Plenty farms (no Hawkes Bay or Wellington farms) had atrazine-resistant C. album. Dicamba-resistant C. album were not detected, nor were atrazine-resistant P. maculosa. Nicosulfuron resistant D. sanguinalis was recorded in 19% of Waikato farms, 6% of Bay of Plenty farms and 9% of Hawkes Bay farms (no Wellington farms). Amaranthus spp., Fallopia convolvulus, Persicaria spp., Solanum spp., Echinochloa crus-galli, Panicum spp. and Setaria spp. were not resistant to any of the herbicides tested. Twenty-nine to 52% of maize farms in the North Island are estimated to have herbicide resistant weeds. Resistance is common in maize farms in Waikato and western Bay of Plenty. Resistance is rare in southern regions, with only one instance of nicosulfuron-resistant D. sanguinalis and no resistant C. album. Most annual weeds in maize are not resistant to herbicides; although atrazine resistant C. album is widespread, it is currently controlled with alternative herbicides. Resistant D. sanguinalis appears to be an emerging problem.
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- 2024
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9. The Electric Spatula: Killing Weeds with Pulsed Microshocks from a Flat-Plate Electrode
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Daniel J. Bloomer, Kerry C. Harrington, Hossein Ghanizadeh, and Trevor K. James
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nonchemical weed control ,site-specific weed management ,electric weeding ,robotic weeding ,electric shocks ,applied energy ,Agriculture - Abstract
Seeking an easy-to-deploy, energy-efficient, non-herbicide weed control method, we tested a flat-plate electrode to apply pulsed electric microshocks (PMS) to a grass and four broadleaf weed species. The method can be deployed via a hand-held unit or as part of a fully automated system to control escape weeds in field crops. The effectiveness of the treatments and the relative energy discharges when applying similar electric doses to the plant leaves or to the plant when pressed to the soil with a flat-plate electrode were compared. The method killed only half of the treated Lolium multiflorum “Winter Star” plants, well below our target rate, but significantly reduced growth rates and indicated that effective treatment of −1 for treating five plants m−2 is possible. Polygonum aviculare L., Amaranthus powellii S. Wats., Amaranthus deflexus, and Solanum nitidibaccatum Bitter plants were successfully controlled, with the energy required to kill 100% of seedlings varying from 0.1 to 0.9 MJ ha−1, indicating that broadleaf weeds are more susceptible. This easily met our target effectiveness and efficiency goals. The discharged energy increased when the electrode pressed the plant to a dry soil surface rather than to the leaves only and increased further when the electrode pressed the plant to a wet soil surface.
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- 2023
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10. Chronic stress-driven glucocorticoid receptor activation programs key cell phenotypes and functional epigenomic patterns in human fibroblasts
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Calvin S. Leung, Oksana Kosyk, Emma M. Welter, Nicholas Dietrich, Trevor K. Archer, and Anthony S. Zannas
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Biological sciences ,Endocrinology ,Molecular biology ,Transcriptomics ,Science - Abstract
Summary: Chronic environmental stress can profoundly impact cell and body function. Although the underlying mechanisms are poorly understood, epigenetics has emerged as a key link between environment and health. The genomic effects of stress are thought to be mediated by the action of glucocorticoid stress hormones, primarily cortisol in humans, which act via the glucocorticoid receptor (GR). To dissect how chronic stress-driven GR activation influences epigenetic and cell states, human fibroblasts underwent prolonged exposure to physiological stress levels of cortisol and/or a selective GR antagonist. Cortisol was found to drive robust changes in cell proliferation, migration, and morphology, which were abrogated by concomitant GR blockade. The GR-driven cell phenotypes were accompanied by widespread, yet genomic context-dependent, changes in DNA methylation and mRNA expression, including gene loci with known roles in cell proliferation and migration. These findings provide insights into how chronic stress-driven functional epigenomic patterns become established to shape key cell phenotypes.
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- 2022
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11. Quantitation and Stability of Nicotine in Canadian Vaping Liquids
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Ivana Kosarac, Guru P. Katuri, Cariton Kubwabo, Shabana Siddique, and Trevor K. Mischki
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e-liquids ,e-cigarettes ,nicotine ,GC-MS ,smoking ,tobacco ,Chemical technology ,TP1-1185 - Abstract
Electronic cigarettes (e-cigarettes, vaping products) have become increasingly popular, with recent increases in use associated with closed systems delivering higher concentrations of nicotine. Most vaping products designed as an alternative to combustible cigarettes contain nicotine. A number of published studies have examined the reported concentrations of nicotine in vaping liquids (e-liquids) and found discrepancies between labelled and measured levels. Some discrepancy can also be explained by the lack of stability of nicotine in these types of products. Recently, a chemical analysis method for the quantitative determination of low and high levels of nicotine in vaping liquids was developed. This method uses dilution with acetonitrile prior to analysis with gas chromatograph mass spectrometry (GC-MS) in single ion monitoring mode (SIM). The developed method was validated using a laboratory-prepared vaping liquid as well as commercially available, nicotine-free products fortified with nicotine in the laboratory. The method detection limit (MDL) and the limit of quantitation (LOQ) for nicotine were calculated to be 0.002 mg/mL and 0.006 mg/mL, respectively. The newly developed method was applied to quantify nicotine in commercially available vaping liquids of various flavour profiles and across a wide range of nicotine concentrations, including those with nicotine salts. Furthermore, a subset of vaping liquids were analyzed to elucidate nicotine stability in various product subtypes. After a period of six months of accelerated storage to mimic one year, the overall mean percent of the original nicotine concentration remaining in the salt-based vaping products was 85% (minimum 64%, maximum 99%) while in the free-base nicotine products it was 74% (minimum 31%, maximum 106%). Nicotine stability in vaping liquids was found to be influenced by the nicotine form (pH) of formulation and its chemical composition. Non-targeted, qualitative analysis of chemical composition of vaping products showed that most constituents were identified and found to be remaining in the products following stability trials; however, three new compounds were tentatively identified in some vaping liquids at the end of the stability trials. Stability studies and the accurate quantitation of nicotine in vaping products can help inform product standards related to the safety, quality and utility of vaping products as a smoking cessation tool.
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- 2023
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12. Expression of UDP Glucuronosyltransferases 2B15 and 2B17 is associated with methylation status in prostate cancer cells
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Farideh Shafiee-Kermani, Skyla T. Carney, Dereje Jima, Utibe C. Utin, LaNeisha B. Farrar, Melvin O. Oputa, Marcono R. Hines, H. Karimi Kinyamu, Kevin W. Trotter, Trevor K. Archer, Cathrine Hoyo, Beverly H. Koller, Stephen J. Freedland, and Delores J. Grant
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human udp-glucuronosyltransferases 2b ,prostate cancer ,methylation ,dna methyltransferases ,epigenetic regulation ,Genetics ,QH426-470 - Abstract
Studies have suggested that abrogated expression of detoxification enzymes, UGT2B15 and UGT2B17, are associated with prostate tumour risk and progression. We investigated the role of EGF on the expression of these enzymes since it interacts with signalling pathways to also affect prostate tumour progression and is additionally associated with decreased DNA methylation. The expression of UGT2B15, UGT2B17, de novo methyltransferases, DNMT3A and DNMT3B was assessed in prostate cancer cells (LNCaP) treated with EGF, an EGFR inhibitor PD16893, and the methyltransferase inhibitor, 5-azacytidine, respectively. The results showed that EGF treatment decreased levels of expression of all four genes and that their expression was reversed by PD16893. Treatment with 5-azacytidine, markedly decreased expression of UGT2B15 and UGT2B17 over 85% as well as significantly decreased expression of DNMT3B, but not the expression of DNMT3A. DNMT3B siRNA treated LNCaP cells had decreased expression of UGT2B15 and UGT2B17, while DNMT3A siRNA treated cells had only moderately decreased UGT2B15 expression. Treatment with DNMT methyltransferase inhibitor, RG108, significantly decreased UGT2B17 expression. Additionally, methylation differences between prostate cancer samples and benign prostate samples from an Illumina 450K Methylation Array study were assessed. The results taken together suggest that hypomethylation of the UGT2B15 and UGT2B17 genes contributes to increased risk of prostate cancer and may provide a putative biomarker or epigenetic target for chemotherapeutics. Mechanistic studies are warranted to determine the role of the methylation marks in prostate cancer.
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- 2021
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13. Degradation of atrazine and bromacil in two forestry waste products
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Trevor K. James, Hossein Ghanizadeh, Kerry C. Harrington, and Nanthi S. Bolan
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Medicine ,Science - Abstract
Abstract The persistence and degradation of two common herbicides, atrazine and bromacil in two organic media, wood pulp and sawdust were compared with two soils. The hypothesis tested was that herbicide degradation will be faster in high organic matter media compared to soil. Degradation of two herbicides was carried out in four different temperature regimes and in sterilised media. The degradation half-life (t½) was determined under above-mentioned conditions then compared to degradation in soil. The degradation as quantified by t½ of the herbicides was generally longer in both organic media. Although microbial degradation was an important factor in the mineralisation of these herbicides, overall, the pH of the media had a more profound effect on the desorption and subsequent degradation rate than the organic carbon content. The results of this study revealed that the hypothesis was only partially correct as organic matter content per se did not strongly relate to degradation rates which were mainly governed by pH and microbial activity.
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- 2021
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14. Behaviour of Abutilon theophrasti in Different Climatic Niches: A New Zealand Case Study
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Hossein Ghanizadeh and Trevor K. James
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CLIMEX-model ,growth degree days ,invasive specie ,site-specific climate condition ,colonisation ,Plant culture ,SB1-1110 - Abstract
Abutilon theophrasti Medik. was initially introduced into New Zealand in the 1940s. Despite its introduction approximately 70 years ago, A. theophrasti infestation in New Zealand has been naturalized to one region only, although climate-based simulation models predicted that A. theophrasti establishment could almost occur in all New Zealand agricultural lands. One possible reason for this discrepancy is that the likelihood of establishment of A. theophrasti may vary across various localities as the climate in New Zealand is complex and varies from warm subtropical in the far north to cool temperate climates in the far south. The objective of this research was to assess and compare the likelihood of A. theophrasti establishment across various localities in New Zealand. For this, experiments were laid out across different regions in New Zealand to assess vegetative and reproductive characteristics in naturalized and casual populations of A. theophrasti. The results showed that the growth and development of both populations varied across different regions, possibly due to variable climatic and geographical conditions such as local temperatures and daily solar radiation. It appears that A. theophrasti is, however, able to grow in many regions in New Zealand, but this species is unlikely to establish and become problematic in the lower half of South Island, where the temperature is lower than optimal temperatures required by this species. A casual population was found to grow better at the early stage of growth compared to a naturalized one. However, both populations reproduced similar amounts of seed in all regions. Overall, the variable vegetative and reproductive responses recorded for A. theophrasti in different locations may suggest that the invasion dynamic of this weed species is unlikely to be similar across different climatic niches in New Zealand.
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- 2022
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15. Vitamin E Acetate Determination in Vaping Liquids and Non-targeted Analysis of Vaping Emissions of Diluents of Concern, Vitamin E Acetate and Medium-Chain Triglycerides Oil
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Ivana Kosarac, Cariton Kubwabo, Guru Prasad Katuri, Dora Petraccone, and Trevor K. Mischki
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vaping ,vitamin E acetate ,medium chain triglycerides ,aerosol ,nicotine ,gc ms ,Chemistry ,QD1-999 - Abstract
During the summer of 2019, cases of lung injury associated with vaping emerged in North America, including among individuals who reported exclusive use of nicotine vaping liquids. Once vitamin E acetate was identified as a potential causative agent a quantitative method based on a simple sample dilution, separation by gas chromatography and analysis by triple quadrupole mass spectrometry (GC MSMS) was developed. Method detection limit (MDL) and limit of quantification (LOQ) were determined at 0.159 µg/mL and 0.505 µg/mL, respectively. The analysis was performed on a subset of 203 commercially sourced nicotine containing vaping liquids of various flavour profile and nicotine range (nicotine free-59 mg/mL) from an internal inventory. The target analyte, Vitamin E Acetate, was not detected in any samples analyzed, as expected, given the reported detection in literature and high association of the chemical with cannabis and not nicotine containing vaping products.
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- 2021
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16. Open Characterization of Vaping Liquids in Canada: Chemical Profiles and Trends
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Ivana Kosarac, Cariton Kubwabo, Xinghua Fan, Shabana Siddique, Dora Petraccone, Wei He, Jun Man, Matthew Gagne, Kelly R. Thickett, and Trevor K. Mischki
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vaping ,nicotine ,non-targeted analysis ,E-cigarettes ,gc ms ,flavours ,Chemistry ,QD1-999 - Abstract
Currently, there is a lack of comprehensive data on the diversity of chemicals present in vaping liquids. To address this gap, a non-targeted analysis of 825 vaping liquids collected between 2017 and 2019 from Canadian retailers was conducted. Prior to mass spectrometry analysis, samples were diluted 1:500 v/v with methanol or acetonitrile. Chemical compound separation and analysis was carried out using gas chromatography and triple quadrupole mass spectrometry (GC-MS/MS) systems operated in the full scan mode and mass range of 35–450 m/z. Mass spectrum for each sample was obtained in electron ionization at 70 eV and processed. Non-targeted identification workflow included use of automated mass spectral deconvolution and identification system (AMDIS), where required, as well as a number of commercially available spectral libraries. In order to validate identities, an in-house database of expected compounds previously detected in vaping liquids was used along with genuine analytical standards for compounds of interest. This resulted in a dataset of over 1,500 unique detected chemicals. Approximately half of these chemical compounds were detected only once in a single product and not in multiple products analyzed. For any sample analyzed, on average, 40% of the chemical constituents appeared to have flavouring properties. The remainder were nicotine and related alkaloids, processing, degradation or indirect additives, natural extractives and compounds with unknown roles. Data published here from the project on the Open Characterization of vaping liquids is unique as it offers a detailed understanding of products’ flavour chemical profiles, the presence and frequency of chemicals of potential health concern, as well as trends and changes in products’ chemical complexity over a three-year period. Non-targeted chemical surveillance such as this present valuable tools to public health officials and researchers in responding to emergent issues such as vaping associated lung injury or informing chemical based strategies which may be aimed at addressing product safety or appeal.
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- 2021
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17. Impacts of Vegetation Removal on Urban Mediterranean Stream Hydrology and Hydraulics
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Trevor K. Eckermann, Danielle S. Hunt, and Alicia M. Kinoshita
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urban streams ,vegetation restoration ,HEC-RAS ,canopy loss ,invasive vegetation ,riparian ,Science - Abstract
Given the widespread presence of non-native vegetation in urban and Mediterranean watersheds, it is important to evaluate how these sensitive ecosystems will respond to activities to manage and restore native vegetation conditions. This research focuses on Del Cerro, a tributary of the San Diego River in California, where non-native vegetation dominates the riparian zone, creating flooding and fire hazards. Field data were collected in 2018 to 2021 and consisted of water depth, streamflow, and stream temperature. Our data set also captured baseline conditions in the floodplain before and after the removal of burned non-native vegetation in November 2020. Observed changes in hydrologic and geomorphic conditions were used to parameterize and calibrate a two-dimensional hydraulic model to simulate urban floodplain hydraulics after vegetation removal. We utilized the U.S. Army Corps of Engineers’ Hydrologic Engineering Center River Assessment System (HEC-RAS) model to simulate the influence of canopy loss and vegetation disturbance and to assess the impacts of vegetation removal on stream restoration. We simulated streamflow, water depth, and flood extent for two scenarios: (1) 2019; pre-restoration where non-native vegetation dominated the riparian area, and (2) 2021; post-restoration following the removal of non-native vegetation and canopy. Flooding after restoration in 2021 was more frequent compared to 2019. We also observed similar flood extents and peak streamflow for storm events that accumulated half the amount of precipitation as pre-restoration conditions. Our results provide insight into the responses of small urban stream reaches to the removal of invasive vegetation and canopy cover.
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- 2022
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18. Micro Electric Shocks Control Broadleaved and Grass Weeds
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Daniel J. Bloomer, Kerry C. Harrington, Hossein Ghanizadeh, and Trevor K. James
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nonchemical weed-control ,site-specific weed management ,electric weeding ,robotic weeding ,electric shocks ,applied energy ,Agriculture - Abstract
A search for energy efficient, non-herbicide weed control methods led to development of a novel electrical weeding technology. This study focuses on weed control efficiency and energy as elements of a system that would include machine vision and robotics to control escape weeds in field crops. Two pulse generation systems, one single and one multiple, were developed and evaluated at different delivered voltages and energies. Greenhouse trials using specially designed and built application and recording technology showed the application of precisely applied micro-shocks with precisely controlled direct current (DC) voltage, pulse number, pulse length and period (hereafter PMS) can kill small Lolium multiflorum Lam., Chenopodium album L., Amaranthus powellii S. Wats. and Solanum nigrum L. plants with minimal energy. Plants took as much as two weeks to die. Increasing applied energy increased effectiveness as determined by plant biomass reduction and death rate. Grasses appear difficult to control once tillering has commenced, and high voltages may destroy leaf blades but not growing points. Broadleaved plants took several days to show evidence of chlorosis which preceded senescence and death. Our results showed that 5 J is sufficient energy to bring about death or severe growth limitation in many seedlings up to 15 cm height. This is as little as 1% of the energy of, and more effective than, ultra-low energy treatments reported in other recent research. To control five herbicide resistant weeds m−2, the required energy would be about 0.25 MJ ha−1 plus transport and actuation energy for weed destruction, as compared to an optimum target of about 20–40 MJ ha−1 including transport suggested in the literature. PMS can effectively control broadleaved weed seedlings and small non-tillering grasses at a fraction of the energy required by commercially available systems. This indicates PMS has potential as a viable technology for hand-held electric weeders or as part of a site-specific robotic weeding system.
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- 2022
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19. Image-guided EBUS bronchoscopy system for lung-cancer staging
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Xiaonan Zang, Ronnarit Cheirsilp, Patrick D. Byrnes, Trevor K. Kuhlengel, Catherine Abendroth, Thomas Allen, Rickhesvar Mahraj, Jennifer Toth, Rebecca Bascom, and William E. Higgins
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Bronchoscopy ,Lung cancer staging ,Endobronchial ultrasound ,Image-guided surgery systems ,Multimodal imaging ,Lymph nodes ,Computer applications to medicine. Medical informatics ,R858-859.7 - Abstract
The staging of the central-chest lymph nodes is a major step in the management of lung-cancer patients. For this purpose, the physician uses a device that integrates videobronchoscopy and an endobronchial ultrasound (EBUS) probe. To biopsy a lymph node, the physician first uses videobronchoscopy to navigate through the airways and then invokes EBUS to localize and biopsy the node. Unfortunately, this process proves difficult for many physicians, with the choice of biopsy site found by trial and error. We present a complete image-guided EBUS bronchoscopy system tailored to lymph-node staging. The system accepts a patient’s 3D chest CT scan, an optional PET scan, and the EBUS bronchoscope’s video sources as inputs. System workflow follows two phases: (1) procedure planning and (2) image-guided EBUS bronchoscopy. Procedure planning derives airway guidance routes that facilitate optimal EBUS scanning and nodal biopsy. During the live procedure, the system’s graphical display suggests a series of device maneuvers to perform and provides multimodal visual cues for locating suitable biopsy sites. To this end, the system exploits data fusion to drive a multimodal virtual bronchoscope and other visualization tools that lead the physician through the process of device navigation and localization. A retrospective lung-cancer patient study and follow-on prospective patient study, performed within the standard clinical workflow, demonstrate the system’s feasibility and functionality. For the prospective study, 60/60 selected lymph nodes (100%) were correctly localized using the system, and 30/33 biopsied nodes (91%) gave adequate tissue samples. Also, the mean procedure time including all user interactions was 6 min 43 s All of these measures improve upon benchmarks reported for other state-of-the-art systems and current practice. Overall, the system enabled safe, efficient EBUS-based localization and biopsy of lymph nodes.
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- 2021
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20. Resistance to post-emergent herbicides is becoming common for grass weeds on New Zealand wheat and barley farms.
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Christopher E Buddenhagen, Trevor K James, Zachary Ngow, Deborah L Hackell, M Phil Rolston, Richard J Chynoweth, Matilda Gunnarsson, Fengshuo Li, Kerry C Harrington, and Hossein Ghanizadeh
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Medicine ,Science - Abstract
To estimate the prevalence of herbicide-resistant weeds, 87 wheat and barley farms were randomly surveyed in the Canterbury region of New Zealand. Over 600 weed seed samples from up to 10 mother plants per taxon depending on abundance, were collected immediately prior to harvest (two fields per farm). Some samples provided by agronomists were tested on an ad-hoc basis. Over 40,000 seedlings were grown to the 2-4 leaf stage in glasshouse conditions and sprayed with high priority herbicides for grasses from the three modes-of-action acetyl-CoA carboxylase (ACCase)-inhibitors haloxyfop, fenoxaprop, clodinafop, pinoxaden, clethodim, acetolactate synthase (ALS)-inhibitors iodosulfuron, pyroxsulam, nicosulfuron, and the 5-enolpyruvyl shikimate 3-phosphate synthase (EPSPS)-inhibitor glyphosate. The highest manufacturer recommended label rates were applied for the products registered for use in New Zealand, often higher than the discriminatory rates used in studies elsewhere. Published studies of resistance were rare in New Zealand but we found weeds survived herbicide applications on 42 of the 87 (48%) randomly surveyed farms, while susceptible reference populations died. Resistance was found for ALS-inhibitors on 35 farms (40%) and to ACCase-inhibitors on 20 (23%) farms. The number of farms with resistant weeds (denominator is 87 farms) are reported for ACCase-inhibitors, ALS-inhibitors, and glyphosate respectively as: Avena fatua (9%, 1%, 0% of farms), Bromus catharticus (0%, 2%, 0%), Lolium spp. (17%, 28%, 0%), Phalaris minor (1%, 6%, 0%), and Vulpia bromoides (0%, not tested, 0%). Not all farms had the weeds present, five had no obvious weeds prior to harvest. This survey revealed New Zealand's first documented cases of resistance in P. minor (fenoxaprop, clodinafop, iodosulfuron) and B. catharticus (pyroxsulam). Twelve of the 87 randomly sampled farms (14%) had ALS-inhibitor chlorsulfuron-resistant sow thistles, mostly Sonchus asper but also S. oleraceus. Resistance was confirmed in industry-supplied samples of the grasses Digitaria sanguinalis (nicosulfuron, two maize farms), P. minor (iodosulfuron, one farm), and Lolium spp. (cases included glyphosate, haloxyfop, pinoxaden, iodosulfuron, and pyroxsulam, 9 farms). Industry also supplied Stellaria media samples that were resistant to chlorsulfuron and flumetsulam (ALS-inhibitors) sourced from clover and ryegrass fields from the North and South Island.
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- 2021
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21. Pre-frontal Cortex Oxygenation Changes During Aerobic Exercise in Elite Athletes Experiencing Sport-Related Concussion
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J. Patrick Neary, Carolynn M. Dudé, Jyotpal Singh, Trevor K. Len, and Yagesh N. Bhambhani
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concussion ,exercise testing ,near-infrared spectroscopy ,pre-frontal cortex oxygenation ,physiology ,athletes ,Neurosciences. Biological psychiatry. Neuropsychiatry ,RC321-571 - Abstract
Aims: Recent research suggests that aerobic exercise can be performed safely within the first week following a concussion injury and that early initiation of exercise may speed recovery. To better understand the physiological changes during a concussion, we tested the hypothesis that mild-to-intense exercise testing can be performed within days immediately following injury, and can be used to discern differences between the concussed and normal healthy state. Thus, the purpose was to observe the cerebral hemodynamic responses to incremental exercise testing performed acutely post-concussion in high-performance athletes.Methods: This study was a within- and between-experimental design, with seven male university ice hockey teams participating. A subgroup of five players acted as control subjects (CON) and was tested at the same time as the 14 concussed (mTBI) players on Day 2, 4, and 7 post-concussion. A 5-min resting baseline and 5-min exercise bouts of mild (EX1), moderate (EX2), and high (EX3) intensity exercise were performed on a cycle ergometer. Near-infrared spectroscopy was used to monitor pre-frontal cortex oxy-haemoglobin (HbO2), deoxy-haemoglobin (HHb), and total blood volume (tHb) changes.Results: ANOVA compared differences between testing days and groups, and although large percentage changes in HbO2 (20–30%), HHb (30–40%), and tHb (30–40%) were recorded, no significant (p ≤ 0.05) differences in cerebral hemodynamics occurred between mTBI vs. CON during aerobic exercise testing on any day post-injury. Furthermore, there was a linear relationship between exercise intensity vs. cerebral hemodynamics during testing for each day (r2 = 0.83–0.99).Conclusion: These results demonstrate two novel findings: (1) mild-to-intense aerobic exercise testing can be performed safely as early as Day 2 post-concussion injury in a controlled laboratory environment; and (2) evidence-based objective measures such as cerebral hemodynamics can easily be collected using near-infrared spectroscopy (NIRS) to monitor physiological changes during the first-week post-injury. This research has important implications for monitoring physiological recovery post-injury and establishing new rehabilitation guidelines.
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- 2020
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22. Estimating the burden of United States workers exposed to infection or disease: A key factor in containing risk of COVID-19 infection.
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Marissa G Baker, Trevor K Peckham, and Noah S Seixas
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Medicine ,Science - Abstract
IntroductionWith the global spread of COVID-19, there is a compelling public health interest in quantifying who is at increased risk of contracting disease. Occupational characteristics, such as interfacing with the public and being in close quarters with other workers, not only put workers at high risk for disease, but also make them a nexus of disease transmission to the community. This can further be exacerbated through presenteeism, the term used to describe the act of coming to work despite being symptomatic for disease. Quantifying the number of workers who are frequently exposed to infection and disease in the workplace, and understanding which occupational groups they represent, can help to prompt public health risk response and management for COVID-19 in the workplace, and subsequent infectious disease outbreaks.MethodsTo estimate the number of United States workers frequently exposed to infection and disease in the workplace, national employment data (by Standard Occupational Classification) maintained by the Bureau of Labor Statistics (BLS) was merged with a BLS O*NET survey measure reporting how frequently workers in each occupation are exposed to infection or disease at work. This allowed us to estimate the number of United States workers, across all occupations, exposed to disease or infection at work more than once a month.ResultsBased on our analyses, approximately 10% (14.4 M) of United States workers are employed in occupations where exposure to disease or infection occurs at least once per week. Approximately 18.4% (26.7 M) of all United States workers are employed in occupations where exposure to disease or infection occurs at least once per month. While the majority of exposed workers are employed in healthcare sectors, other occupational sectors also have high proportions of exposed workers. These include protective service occupations (e.g. police officers, correctional officers, firefighters), office and administrative support occupations (e.g. couriers and messengers, patient service representatives), education occupations (e.g. preschool and daycare teachers), community and social services occupations (community health workers, social workers, counselors), and even construction and extraction occupations (e.g. plumbers, septic tank installers, elevator repair).ConclusionsThe large number of persons employed in occupations with frequent exposure to infection and disease underscore the importance of all workplaces developing risk response plans for COVID-19. Given the proportion of the United States workforce exposed to disease or infection at work, this analysis also serves as an important reminder that the workplace is a key locus for public health interventions, which could protect both workers and the communities they serve.
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- 2020
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23. Radioprotective agents to prevent cellular damage due to ionizing radiation
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Tyler A. Smith, Daniel R. Kirkpatrick, Sean Smith, Trevor K. Smith, Tate Pearson, Aparna Kailasam, Kortney Z. Herrmann, Johanna Schubert, and Devendra K. Agrawal
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Antioxidant ,Computed tomography ,Ionizing radiation ,Medical imaging ,Radioprotectant ,Mitigators ,Medicine - Abstract
Abstract Medical imaging has become a central component of patient care to ensure early and accurate diagnosis. Unfortunately, many imaging modalities use ionizing radiation to generate images. Ionizing radiation even in low doses can cause direct DNA damage and generate reactive oxygen species and free radicals, leading to DNA, protein, and lipid membrane damage. This cell damage can lead to apoptosis, necrosis, teratogenesis, or carcinogenesis. As many as 2% of cancers (and an associated 15,000 deaths annually) can be linked to computed tomography exposure alone. Radioprotective agents have been investigated using various models including cells, animals, and recently humans. The data suggest that radioprotective agents working through a variety of mechanisms have the potential to decrease free radical damage produced by ionizing radiation. Radioprotective agents may be useful as an adjunct to medical imaging to reduced patient morbidity and mortality due to ionizing radiation exposure. Some radioprotective agents can be found in high quantities in antioxidant rich foods, suggesting that a specific diet recommendation could be beneficial in radioprotection.
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- 2017
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24. Tumor suppressor SMARCB1 suppresses super-enhancers to govern hESC lineage determination
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Lee F Langer, James M Ward, and Trevor K Archer
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SMARCB1 ,chromatin ,super-enhancer ,pluripotency ,accessibility ,transcription ,Medicine ,Science ,Biology (General) ,QH301-705.5 - Abstract
The SWI/SNF complex is a critical regulator of pluripotency in human embryonic stem cells (hESCs), and individual subunits have varied and specific roles during development and in diseases. The core subunit SMARCB1 is required for early embryonic survival, and mutations can give rise to atypical teratoid/rhabdoid tumors (AT/RTs) in the pediatric central nervous system. We report that in contrast to other studied systems, SMARCB1 represses bivalent genes in hESCs and antagonizes chromatin accessibility at super-enhancers. Moreover, and consistent with its established role as a CNS tumor suppressor, we find that SMARCB1 is essential for neural induction but dispensable for mesodermal or endodermal differentiation. Mechanistically, we demonstrate that SMARCB1 is essential for hESC super-enhancer silencing in neural differentiation conditions. This genomic assessment of hESC chromatin regulation by SMARCB1 reveals a novel positive regulatory function at super-enhancers and a unique lineage-specific role in regulating hESC differentiation.
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- 2019
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25. Acute depletion of BRG1 reveals its primary function as an activator of transcription
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Ren, Gang, Ku, Wai Lim, Ge, Guangzhe, Hoffman, Jackson A., Kang, Jee Youn, Tang, Qingsong, Cui, Kairong, He, Yong, Guan, Yukun, Gao, Bin, Liu, Chengyu, Archer, Trevor K., and Zhao, Keji
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- 2024
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26. Ash Presence and Abundance Derived from Composite Landsat and Sentinel-2 Time Series and Lidar Surface Models in Minnesota, USA
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Trevor K. Host, Matthew B. Russell, Marcella A. Windmuller-Campione, Robert A. Slesak, and Joseph F. Knight
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Google Earth Engine ,Landsat ,lidar ,Fraxinus ,forest health ,Science - Abstract
Ash trees (Fraxinus spp.) are a prominent species in Minnesota forests, with an estimated 1.1 billion trees in the state, totaling approximately 8% of all trees. Ash trees are threatened by the invasive emerald ash borer (Agrilus planipennis Fairmaire), which typically results in close to 100% tree mortality within one to five years of infestation. A detailed, wall-to-wall map of ash presence is highly desirable for forest management and monitoring applications. We used Google Earth Engine to compile Landsat time series analysis, which provided unique information on phenologic patterns across the landscape to identify ash species. Topographic position information derived from lidar was added to improve spatial maps of ash abundance. These input data were combined to produce a classification map and identify the abundance of ash forests that exist in the state of Minnesota. Overall, 12,524 km2 of forestland was predicted to have greater than 10% probability of ash species present. The overall accuracy of the composite ash presence/absence map was 64% for all ash species and 72% for black ash, and classification accuracy increased with the length of the time series. Average height derived from lidar was the best model predictor for ash basal area (R2 = 0.40), which, on average, was estimated as 16.1 m2 ha−1. Information produced from this map will be useful for natural resource managers and planners in developing forest management strategies which account for the spatial distribution of ash on the landscape. The approach used in this analysis is easily transferable and broadly scalable to other regions threatened with forest health problems such as invasive insects.
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- 2020
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27. Comparative Seasonal Respiratory Virus Epidemic Timing in Utah
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Zayne Y. Callahan, Trevor K. Smith, Celeste Ingersoll, Rebecca Gardner, E. Kent Korgenski, and Chantel D. Sloan
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influenza ,viral interference ,wavelet ,Microbiology ,QR1-502 - Abstract
Previous studies have found evidence of viral interference between seasonal respiratory viruses. Using laboratory-confirmed data from a Utah-based healthcare provider, Intermountain Health Care, we analyzed the time-specific patterns of respiratory syncytial virus (RSV), influenza A, influenza B, human metapneumovirus, rhinovirus, and enterovirus circulation from 2004 to 2018, using descriptive methods and wavelet analysis (n = 89,462) on a local level. The results showed that RSV virus dynamics in Utah were the most consistent of any of the viruses studied, and that the other seasonal viruses were generally in synchrony with RSV, except for enterovirus (which mostly occurs late summer to early fall) and influenza A and B during pandemic years.
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- 2020
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28. BRG1 governs glucocorticoid receptor interactions with chromatin and pioneer factors across the genome
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Jackson A Hoffman, Kevin W Trotter, James M Ward, and Trevor K Archer
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chromatin ,transcription factors ,brg1 ,glucocorticoid receptor ,pioneer factors ,histone modifications ,Medicine ,Science ,Biology (General) ,QH301-705.5 - Abstract
The Glucocorticoid Receptor (GR) alters transcriptional activity in response to hormones by interacting with chromatin at GR binding sites (GBSs) throughout the genome. Our work in human breast cancer cells identifies three classes of GBSs with distinct epigenetic characteristics and reveals that BRG1 interacts with GBSs prior to hormone exposure. The GBSs pre-occupied by BRG1 are more accessible and transcriptionally active than other GBSs. BRG1 is required for a proper and robust transcriptional hormone response and knockdown of BRG1 blocks recruitment of the pioneer factors FOXA1 and GATA3 to GBSs. Finally, GR interaction with FOXA1 and GATA3 binding sites was restricted to sites pre-bound by BRG1. These findings demonstrate that BRG1 establishes specialized chromatin environments that define multiple classes of GBS. This in turn predicts that GR and other transcriptional activators function via multiple distinct chromatin-based mechanisms to modulate the transcriptional response.
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- 2018
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29. RPE vs. Percentage 1RM Loading in Periodized Programs Matched for Sets and Repetitions
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Eric R. Helms, Ryan K. Byrnes, Daniel M. Cooke, Michael H. Haischer, Joseph P. Carzoli, Trevor K. Johnson, Matthew R. Cross, John B. Cronin, Adam G. Storey, and Michael C. Zourdos
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perceived exertion ,resistance training ,strength ,autoregulation ,powerlifting ,Physiology ,QP1-981 - Abstract
Purpose: To investigate differences between rating of perceived exertion (RPE) and percentage one-repetition maximum (1RM) load assignment in resistance-trained males (19–35 years) performing protocols with matched sets and repetitions differentiated by load-assignment.Methods: Participants performed squats then bench press 3x/weeks in a daily undulating format over 8-weeks. Participants were counterbalanced by pre-test 1RM then assigned to percentage 1RM (1RMG, n = 11); load-assignment via percentage 1RMs, or RPE groups (RPEG, n = 10); participant-selected loads to reach target RPE ranges. Ultrasonography determined pre and post-test pectoralis (PMT), and vastus lateralis muscle thickness at 50 (VLMT50) and 70% (VLMT70) femur-length.Results: Bench press (1RMG +9.64 ± 5.36; RPEG + 10.70 ± 3.30 kg), squat (1RMG + 13.91 ± 5.89; RPEG + 17.05 ± 5.44 kg) and their combined-total 1RMs (1RMG + 23.55 ± 10.38; RPEG + 27.75 ± 7.94 kg) increased (p < 0.05) in both groups as did PMT (1RMG + 1.59 ± 1.33; RPEG +1.90 ± 1.91 mm), VLMT50 (1RMG +2.13 ± 1.95; RPEG + 1.85 ± 1.97 mm) and VLMT70 (1RMG + 2.40 ± 2.22; RPEG + 2.31 ± 2.27 mm). Between-group differences were non-significant (p > 0.05). Magnitude-based inferences revealed 79, 57, and 72% chances of mean small effect size (ES) advantages for squat; ES 90% confidence limits (CL) = 0.50 ± 0.63, bench press; ES 90% CL = 0.28 ± 0.73, and combined-total; ES 90% CL = 0.48 ± 0.68 respectively, in RPEG. There were 4, 14, and 6% chances 1RMG had a strength advantage of the same magnitude, and 18, 29, and 22% chances, respectively of trivial differences between groups.Conclusions: Both loading-types are effective. However, RPE-based loading may provide a small 1RM strength advantage in a majority of individuals.
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- 2018
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30. Phase-based metamorphosis of diffusion lesion in relation to perfusion values in acute ischemic stroke
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Islem Rekik, Stéphanie Allassonnière, Marie Luby, Trevor K. Carpenter, and Joanna M. Wardlaw
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Metamorphosis ,Ischemic stroke ,Lesion evolution ,Diffusion imaging ,Perfusion imaging ,Magnetic resonance imaging ,Computer applications to medicine. Medical informatics ,R858-859.7 ,Neurology. Diseases of the nervous system ,RC346-429 - Abstract
Examining the dynamics of stroke ischemia is limited by the standard use of 2D-volume or voxel-based analysis techniques. Recently developed spatiotemporal models such as the 4D metamorphosis model showed promise for capturing ischemia dynamics. We used a 4D metamorphosis model to evaluate acute ischemic stroke lesion morphology from the acute diffusion-weighted imaging (DWI) to final T2-weighted imaging (T2-w). In 20 representative patients, we metamorphosed the acute lesion to subacute lesion to final infarct. From the DWI lesion deformation maps we identified dynamic lesion areas and examined their association with perfusion values inside and around the lesion edges, blinded to reperfusion status. We then tested the model in ten independent patients from the STroke Imaging Repository (STIR). Perfusion values varied widely between and within patients, and were similar in contracting and expanding DWI areas in many patients in both datasets. In 25% of patients, the perfusion values were higher in DWI-contracting than DWI-expanding areas. A similar wide range of perfusion values and ongoing expansion and contraction of the DWI lesion were seen subacutely. There was more DWI contraction and less expansion in patients who received thrombolysis, although with widely ranging perfusion values that did not differ. 4D metamorphosis modeling shows promise as a method to improve use of multimodal imaging to understand the evolution of acute ischemic tissue towards its fate.
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- 2015
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31. 3D fatigue crack path deflection and residual stresses in 17-4PH stainless steel rod
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Shoemaker, Trevor K, Harris, Zachary D, Smudde, Christine M, Hill, Michael R, and Burns, James T
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Engineering ,Materials Engineering ,17-4PH ,Residual stress ,Crack path ,Closure ,Material product form ,Civil Engineering ,Mechanical Engineering ,Mechanical Engineering & Transports ,Civil engineering ,Materials engineering ,Mechanical engineering - Abstract
Damage tolerant structures require accurate fatigue crack growth rate models for life prediction. Central to these models are fracture mechanics similitude and empirically gathered growth rates. In this work, standard test methods failed to achieve similitude for 17-4PH stainless steel round-rod but succeeded for plate. Material product form differences are interrogated through constant ΔK tests, crack path analysis, residual stress (RS) characterization, and growth rate simulation. Analyses revealed that quench-induced RS in the round-rod promoted a non-planar, 3D crack path with closure effects. Strategies to mitigate the RS/path effects are evaluated by controlling constraint, closure, environment, and heat treatment.
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- 2023
32. Machine learning-based morphological quantification of replicative senescence in human fibroblasts
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Welter, Emma M., Benavides, Sofia, Archer, Trevor K., Kosyk, Oksana, and Zannas, Anthony S.
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- 2024
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33. Running Neuroimaging Applications on Amazon Web Services: How, When, and at What Cost?
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Tara M. Madhyastha, Natalie Koh, Trevor K. M. Day, Moises Hernández-Fernández, Austin Kelley, Daniel J. Peterson, Sabreena Rajan, Karl A. Woelfer, Jonathan Wolf, and Thomas J. Grabowski
- Subjects
cloud computing ,neuroimaging pipelines ,workflow ,reproducibility ,Neurosciences. Biological psychiatry. Neuropsychiatry ,RC321-571 - Abstract
The contribution of this paper is to identify and describe current best practices for using Amazon Web Services (AWS) to execute neuroimaging workflows “in the cloud.” Neuroimaging offers a vast set of techniques by which to interrogate the structure and function of the living brain. However, many of the scientists for whom neuroimaging is an extremely important tool have limited training in parallel computation. At the same time, the field is experiencing a surge in computational demands, driven by a combination of data-sharing efforts, improvements in scanner technology that allow acquisition of images with higher image resolution, and by the desire to use statistical techniques that stress processing requirements. Most neuroimaging workflows can be executed as independent parallel jobs and are therefore excellent candidates for running on AWS, but the overhead of learning to do so and determining whether it is worth the cost can be prohibitive. In this paper we describe how to identify neuroimaging workloads that are appropriate for running on AWS, how to benchmark execution time, and how to estimate cost of running on AWS. By benchmarking common neuroimaging applications, we show that cloud computing can be a viable alternative to on-premises hardware. We present guidelines that neuroimaging labs can use to provide a cluster-on-demand type of service that should be familiar to users, and scripts to estimate cost and create such a cluster.
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- 2017
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34. Transcriptional Repression by the BRG1-SWI/SNF Complex Affects the Pluripotency of Human Embryonic Stem Cells
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Xiaoli Zhang, Bing Li, Wenguo Li, Lijuan Ma, Dongyan Zheng, Leping Li, Weijing Yang, Min Chu, Wei Chen, Richard B. Mailman, Jun Zhu, Guoping Fan, Trevor K. Archer, and Yuan Wang
- Subjects
Medicine (General) ,R5-920 ,Biology (General) ,QH301-705.5 - Abstract
The SWI/SNF complex plays an important role in mouse embryonic stem cells (mESCs), but it remains to be determined whether this complex is required for the pluripotency of human ESCs (hESCs). Using RNAi, we demonstrated that depletion of BRG1, the catalytic subunit of the SWI/SNF complex, led to impaired self-renewing ability and dysregulated lineage specification of hESCs. A unique composition of the BRG1-SWI/SNF complex in hESCs was further defined by the presence of BRG1, BAF250A, BAF170, BAF155, BAF53A, and BAF47. Genome-wide expression analyses revealed that BRG1 participated in a broad range of biological processes in hESCs through pathways different from those in mESCs. In addition, chromatin immunoprecipitation sequencing (ChIP-seq) demonstrated that BRG1 played a repressive role in transcriptional regulation by modulating the acetylation levels of H3K27 at the enhancers of lineage-specific genes. Our data thus provide valuable insights into molecular mechanisms by which transcriptional repression affects the self-renewal and differentiation of hESCs.
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- 2014
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35. Using longitudinal metamorphosis to examine ischemic stroke lesion dynamics on perfusion-weighted images and in relation to final outcome on T2-w images
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Islem Rekik, Stéphanie Allassonnière, Trevor K. Carpenter, and Joanna M. Wardlaw
- Subjects
Longitudinal metamorphosis ,Acute/subacute ischemic stroke ,Dynamic evolution ,Perfusion ,Computer applications to medicine. Medical informatics ,R858-859.7 ,Neurology. Diseases of the nervous system ,RC346-429 - Abstract
We extend the image-to-image metamorphosis into constrained longitudinal metamorphosis. We apply it to estimate an evolution scenario, in patients with acute ischemic stroke, of both scattered and solitary ischemic lesions visible on serial MR perfusion weighted imaging from acute to subacute stages. We then estimate a patient-specific residual map that enables us to capture the most relevant shape and intensity changes, continuously, as the lesion evolves from acute through subacute to chronic timepoints until merging into the final image. We detect areas with high residuals (i.e., high dynamics) and identify areas that became part of the final T2-w lesion obtained at ≥1 month after stroke. This allows the investigation of the dynamic influence of perfusion values on the final lesion outcome as seen on T2-w imaging. The model provides detailed insights into stroke lesion dynamic evolution in space and time that will help identify factors that determine final outcome and identify targets for interventions to improve outcome.
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- 2014
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36. An Evidence-Based Objective Study Protocol for Evaluating Cardiovascular and Cerebrovascular Indices Following Concussion: The Neary Protocol
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J. Patrick Neary, Jyotpal Singh, Scott A. Bishop, Ryan T. Dech, Matthew J. A. Butz, and Trevor K. Len
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concussion ,physiological ,heart rate variability ,cerebral blood flow ,oxygenation ,Biology (General) ,QH301-705.5 - Abstract
Introduction: The prevalence and incidence of sport-related concussion have continued to increase over the past decade, and researchers from various backgrounds strive for evidenced-based clinical assessment and management. When diagnosing and managing a concussion, a battery of tests from several domains (e.g., symptom reporting, neurocognitive, physiology) must be used. In this study, we propose and develop an objective, evidence-based protocol to assess the pathophysiology of the brain by using non-invasive methods. Methods: Contact sport athletes (n = 300) will be assessed at the beginning of the season in a healthy state to establish baseline values, and then prospectively followed if a mild traumatic brain injury (mTBI) occurs on approximately days 1–2, 3–5, 7–10, 21, 30, and subsequently thereafter, depending on the severity of injury. The protocol includes spontaneous measurements at rest, during head postural change, controlled breathing maneuvers for cerebrovascular reactivity, a neurovascular coupling stimuli, and a baroreflex/autoregulation maneuver. Physiological data collection will include cerebral blood flow velocity, cerebral oxygenation, respiratory gases for end-tidal oxygen and carbon dioxide, finger photoplethysmography for blood pressure, seismocardiography for cardiac mechanics, and electrocardiography. Conclusion, Limitations, and Ethics: The protocol will provide an objective, physiological evidence-based approach in an attempt to better diagnose concussion to aid in return-to-play or -learn. Ethics approval has been granted by the University Research Ethics Board.
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- 2019
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37. Downstream Antisense Transcription Predicts Genomic Features That Define the Specific Chromatin Environment at Mammalian Promoters.
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Christopher A Lavender, Kimberly R Cannady, Jackson A Hoffman, Kevin W Trotter, Daniel A Gilchrist, Brian D Bennett, Adam B Burkholder, Craig J Burd, David C Fargo, and Trevor K Archer
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Genetics ,QH426-470 - Abstract
Antisense transcription is a prevalent feature at mammalian promoters. Previous studies have primarily focused on antisense transcription initiating upstream of genes. Here, we characterize promoter-proximal antisense transcription downstream of gene transcription starts sites in human breast cancer cells, investigating the genomic context of downstream antisense transcription. We find extensive correlations between antisense transcription and features associated with the chromatin environment at gene promoters. Antisense transcription downstream of promoters is widespread, with antisense transcription initiation observed within 2 kb of 28% of gene transcription start sites. Antisense transcription initiates between nucleosomes regularly positioned downstream of these promoters. The nucleosomes between gene and downstream antisense transcription start sites carry histone modifications associated with active promoters, such as H3K4me3 and H3K27ac. This region is bound by chromatin remodeling and histone modifying complexes including SWI/SNF subunits and HDACs, suggesting that antisense transcription or resulting RNA transcripts contribute to the creation and maintenance of a promoter-associated chromatin environment. Downstream antisense transcription overlays additional regulatory features, such as transcription factor binding, DNA accessibility, and the downstream edge of promoter-associated CpG islands. These features suggest an important role for antisense transcription in the regulation of gene expression and the maintenance of a promoter-associated chromatin environment.
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- 2016
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38. Using Make for Reproducible and Parallel Neuroimaging Workflow and Quality Assurance
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Mary K. Askren, Trevor K McAllister-Day, Natalie eKoh, Zoe eMestre, Jennifer N Dines, Benjamin A Korman, Susan J Melhorn, Daniel J Peterson, Matthew ePeverill, Xiaoyan eQin, Swati D Rane, Melissa A Reilly, Maya A Reiter, Kelly A Sambrook, Karl A Woelfer, Thomas J Grabowski, and Tara M Madhyastha
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Neuroimaging methods ,Quality Assurance ,reproducibility ,workflow ,neuroimaging pipelines ,Neurosciences. Biological psychiatry. Neuropsychiatry ,RC321-571 - Abstract
The contribution of this paper is to describe how we can program neuroimaging workflow using Make, a software development tool designed for describing how to build executables from source files. We show that we can achieve many of the features of more sophisticated neuroimaging pipeline systems, including reproducibility, parallelization, fault tolerance, and quality assurance reports. We suggest that Make represents a large step towards these features with only a modest increase in programming demands over shell scripts. This approach reduces the technical skill and time required to write, debug, and maintain neuroimaging workflows in a dynamic environment, where pipelines are often modified to accommodate new best practices or to study the effect of alternative preprocessing steps, and where the underlying packages change frequently. This paper has a comprehensive accompanying manual with lab practicals and examples (see Supplemental Materials) and all data, scripts and makefiles necessary to run the practicals and examples are available in the makepipelines project at NITRC.
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- 2016
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39. Vegetation and channel recovery ten years following the Waldo Canyon Fire of Colorado
- Author
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Chin, Anne, primary, Burton, Jonathan W., additional, Humphreys, Kevin M., additional, Florsheim, Joan L., additional, Kinoshita, Alicia M., additional, Andreano, Emily C., additional, and Eckermann, Trevor K., additional
- Published
- 2024
- Full Text
- View/download PDF
40. Factors That Determine Wider Solidarity Responses After a Major Incident or Disaster
- Author
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James, Trevor K, primary, Tekin, Selin, additional, and Zagefka, Hanna, additional
- Published
- 2024
- Full Text
- View/download PDF
41. Demonstrating the Elusive Outcomes of Decision-Making, Information-Seeking, and Adaptability: A Market Simulation Game for Engineering Students
- Author
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Morelock, John R., Salado, Alejandro, Lakeh, Arash Baghaei, and Richards, Trevor K.
- Abstract
In undergraduate engineering education, students are often overexposed to problem-solving methods that are unrepresentative of how engineers solve problems in practice. For decision-making problems, in particular, students are commonly taught to compare alternative solutions using known and provided information. However, many real-world decision-making problems require a broader range of problem-solving strategies, including information seeking, extrapolation of a decision's consequences, and compromise between parties with competing objectives. To advance engineering educators' capacity to address this need, we developed a simulation game activity designed to offer industrial engineering seniors experience in solving realistic decision-making problems. The simulation game involved students working in teams that role-played as different types of companies in a global smartphone market, where teams needed to negotiate with one another to establish profitable contracts within the game's ruleset. Using a qualitative assessment instrument we developed through prior research, we evaluated how well success in the game aligned with learning outcome achievement in constrained decision-making, information-seeking, and adaptability. Though the game has opportunities for improvement, student success in the game was aligned with excellence in constrained decision-making, and occasionally aligned with excellence in adaptability, and effort to seek information that could guide team decisions. Additionally, student actions during the game have potential to initiate student discourse on the role of engineering ethics in managerial decision-making, which may be of interest to many engineering programs. Finally, we comment on how our new assessment instrument affected student learning and related implications for assessment in engineering education more broadly. Our market simulation game was an effective instructional tool to allow students to demonstrate our intended learning outcomes, and other instructors with similar intended outcomes may find it a valuable tool for their courses as well.
- Published
- 2021
42. Scaled experiment design for transient coupled CFD-reactor physics model for HENRI
- Author
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Warren, Austin M., Mignot, Guillaume P., Howard, Trevor K., and Marcum, Wade R.
- Published
- 2024
- Full Text
- View/download PDF
43. 21-(4-Methylphenylsulfonyl)-4,7,13,16-tetraoxa-1,10,21-triazabicyclo[8.8.5]tricosane-19,23-dione: an N-tosylated macrobicyclic dilactam
- Author
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Trevor K. Ellis, Stephen M. Clayton Jr, Douglas R. Powell, and Richard W. Taylor
- Subjects
Crystallography ,QD901-999 - Abstract
The macrobicyclic title compound, C23H35N3O8S, contains two tertiary amide bridgehead N atoms and a toluenesulfonamide N atom in the center of the five-atom bridging strand. The molecule has a central cavity that is defined by the 18-membered ring identified by the N2O4 donor atom set and two 15-membered rings with N3O2 donor atom sets. The toluenesulfonamide N atom adopts an exo orientation with respect to the central cavity, and the tosyl group is oriented on one side of the aza-bridging strand that connects the bridgehead N atoms.
- Published
- 2011
- Full Text
- View/download PDF
44. Multiple distinct stimuli increase measured nucleosome occupancy around human promoters.
- Author
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Chuong D Pham, Hillel I Sims, Trevor K Archer, and Gavin R Schnitzler
- Subjects
Medicine ,Science - Abstract
Nucleosomes can block access to transcription factors. Thus the precise localization of nucleosomes relative to transcription start sites and other factor binding sites is expected to be a critical component of transcriptional regulation. Recently developed microarray approaches have allowed the rapid mapping of nucleosome positions over hundreds of kilobases (kb) of human genomic DNA, although these approaches have not yet been widely used to measure chromatin changes associated with changes in transcription. Here, we use custom tiling microarrays to reveal changes in nucleosome positions and abundance that occur when hormone-bound glucocorticoid receptor (GR) binds to sites near target gene promoters in human osteosarcoma cells. The most striking change is an increase in measured nucleosome occupancy at sites spanning ∼1 kb upstream and downstream of transcription start sites, which occurs one hour after addition of hormone, but is lost at 4 hours. Unexpectedly, this increase was seen both on GR-regulated and GR-non-regulated genes. In addition, the human SWI/SNF chromatin remodeling factor (a GR co-activator) was found to be important for increased occupancy upon hormone treatment and also for low nucleosome occupancy without hormone. Most surprisingly, similar increases in nucleosome occupancy were also seen on both regulated and non-regulated promoters during differentiation of human myeloid leukemia cells and upon activation of human CD4+ T-cells. These results indicate that dramatic changes in chromatin structure over ∼2 kb of human promoters may occur genomewide and in response to a variety of stimuli, and suggest novel models for transcriptional regulation.
- Published
- 2011
- Full Text
- View/download PDF
45. The Rho-Rock-Myosin signaling axis determines cell-cell integrity of self-renewing pluripotent stem cells.
- Author
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Nicole Harb, Trevor K Archer, and Noboru Sato
- Subjects
Medicine ,Science - Abstract
BackgroundEmbryonic stem (ES) cells self-renew as coherent colonies in which cells maintain tight cell-cell contact. Although intercellular communications are essential to establish the basis of cell-specific identity, molecular mechanisms underlying intrinsic cell-cell interactions in ES cells at the signaling level remain underexplored.Methodology/principal findingsHere we show that endogenous Rho signaling is required for the maintenance of cell-cell contacts in ES cells. siRNA-mediated loss of function experiments demonstrated that Rock, a major effector kinase downstream of Rho, played a key role in the formation of cell-cell junctional assemblies through regulation of myosin II by controlling a myosin light chain phosphatase. Chemical engineering of this signaling axis by a Rock-specific inhibitor revealed that cell-cell adhesion was reversibly controllable and dispensable for self-renewal of mouse ES cells as confirmed by chimera assay. Furthermore, a novel culture system combining a single synthetic matrix, defined medium, and the Rock inhibitor fully warranted human ES cell self-renewal independent of animal-derived matrices, tight cell contacts, or fibroblastic niche-forming cells as determined by teratoma formation assay.Conclusions/significanceThese findings demonstrate an essential role of the Rho-Rock-Myosin signaling axis for the regulation of basic cell-cell communications in both mouse and human ES cells, and would contribute to advance in medically compatible xeno-free environments for human pluripotent stem cells.
- Published
- 2008
- Full Text
- View/download PDF
46. Molecular detection of multidrug and methicillin resistance in Staphylococcus aureus isolated from wild pigeons (Columba livia) in South Africa
- Author
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Wilson, Trevor K., Zishiri, Oliver T., and El Zowalaty, Mohamed E.
- Published
- 2024
- Full Text
- View/download PDF
47. Molecular detection of virulence genes in Staphylococcus aureus isolated from wild pigeons (Columba domestica livia) in KwaZulu-Natal in South Africa
- Author
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Wilson, Trevor K., Zishiri, Oliver T., and El Zowalaty, Mohamed E.
- Published
- 2024
- Full Text
- View/download PDF
48. Nanometer-scale porosity evolution and mechanical properties of additively manufactured 17-4PH stainless steel
- Author
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Shoemaker, Trevor K., Harris, Zachary D., and Burns, James T.
- Published
- 2024
- Full Text
- View/download PDF
49. A Broadened Estimate of Syntactic and Lexical Ability from the MB-CDI
- Author
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Day, Trevor K. M. and Elison, Jed T.
- Abstract
A critical question in the study of language development is to understand lexical and syntactic acquisition, which play different roles in speech to the extent it would be natural to surmise they are acquired differently. As measured through the comprehension and production of closed-class words, syntactic ability emerges at roughly the 400-word mark. However, a significant proportion of the developmental work uses a coarse combination of function and content words on the MacArthur-Bates Communicative Development Inventory (MB-CDI). Using the MB-CDI Wordbank database, we implemented a factor analytic approach to distinguish between lexical and syntactic development from the Words and Sentences (WS) form that involves both function words and the explicit categorizations. Although the Words and Gestures (WG) form did not share the factor structure, common WG/WS elements recapitulate the expected age-related changes. This parsing of the MB-CDI may prove simple, yet fruitful in subsequent investigation.
- Published
- 2022
- Full Text
- View/download PDF
50. Profitable management of a finite herbicide resource
- Author
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Doole, Graeme J. and James, Trevor K.
- Published
- 2023
- Full Text
- View/download PDF
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