382 research outputs found
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The Physio-Chemical Properties for the Interior of Enceladus
We have reviewed the current physical and chemical conditions of the Enceladus sub-surface environment, including the composition, temperature, pH and pressure. Here we have defined some of these parameters and, through the aid of modelling, will define and refine the remaining parameters needed for our experimental work. Simulations of the chemical reactions occurring within Enceladus can then be carried
out to advance our understanding of the internal environment of Enceladus and help evaluate its potential habitability. Once a better understanding of the chemical reactions occurring at the rock-water interface has been carried out, then potential analogues on Earth can be evaluated and known microbial life can be tested to see if it could survive the conditions of Enceladus
Angiomatous meningiomas have a distinct genetic profile with multiple chromosomal polysomies including polysomy of chromosome 5
Meningiomas are a diverse group of tumors with a broad spectrum of histologic features. There are over 12 variants of meningioma, whose genetic features are just beginning to be described. Angiomatous meningioma is a World Health Organization (WHO) meningioma variant with a predominance of blood vessels. They are uncommon and confirming the histopathologic classification can be challenging. Given a lack of biomarkers that define the angiomatous subtype and limited understanding of the genetic changes underlying its tumorigenesis, we compared the genomic characteristics of angiomatous meningioma to more common meningioma subtypes. While typical grade I meningiomas demonstrate monosomy of chromosome 22 or lack copy number aberrations, 13 of 14 cases of angiomatous meningioma demonstrated a distinct copy number profile – polysomies of at least one chromosome, but often of many, especially in chromosomes 5, 13, and 20. WHO grade II atypical meningiomas with angiomatous features have both polysomies and genetic aberrations characteristic of other atypical meningiomas. Sequencing of over 560 cancer-relevant genes in 16 cases of angiomatous meningioma showed that these tumors lack common mutations found in other variants of meningioma. Our study demonstrates that angiomatous meningiomas have distinct genomic features that may be clinically useful for their diagnosis
Integrated top-down and bottom-up mass spectrometry characterization of Escherichia coli ribosomal protein heterogeneity: identification of protein isoforms and post-translational modifications
The bacterial genome exhibits notable plasticity but is relatively static when compared to the proteome. Protein expression can vary significantly depending on environmental factors, growth stage or stochastic processes within cells. This highly variable character, coupled with the large dynamic range of protein expression levels and the complexity achieved through processes such as post-translational modification (PTM), necessitate accurate, sensitive and high-throughput methods of analysis. The primary aim of this research was to develop an integrated experimental and analysis workflow that combines the analytical power of top-down and bottom-up mass spectrometry towards protein isoform and PTM characterization. We apply this approach to a comprehensive characterization of Escherichia coli ribosomal protein isoform heterogeneity. Our findings uncovered a significant level of heterogeneity in the post-translational modification of a number of ribosomal proteins, revealing a possible mechanism for the regulation of ribosomal protein function both within and beyond the ribosome
Customer engagement in tourism and hospitality research
Customer engagement (CE), defined as a customer's resource investment in his/her brand or firm interactions, has evolved into an important tourism and hospitality marketing metric in the last decade. However, despite existing insight in this area, dynamic CE remains in flux, requiring further investigation. In this chapter, we discuss CE's key theoretical foundation/underpinnings, perspectives, operationalization(s)/measurement, antecedents, consequences, mediators, moderators, approaches and methods, thus offering a foundation upon which the remainder of this book is built.info:eu-repo/semantics/acceptedVersio
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Characterising the Transfer of Biomarkers within the Phobos-Mars System
Procedural and analytical developments required for impact and heat investigation into the detection of biomarkers transported from Mars to Phobos
MicroRNAs hsa-miR-99b, hsa-miR-330, hsa-miR-126 and hsa-miR-30c: Potential Diagnostic Biomarkers in Natural Killer (NK) Cells of Patients with Chronic Fatigue Syndrome (CFS)/ Myalgic Encephalomyelitis (ME)
Chronic Fatigue Syndrome (CFS/ME) is a complex multisystem disease of unknown aetiology which causes debilitating symptoms in up to 1% of the global population. Although a large cohort of genes have been shown to exhibit altered expression in CFS/ME patients, it is currently unknown whether microRNA (miRNA) molecules which regulate gene translation contribute to disease pathogenesis. We hypothesized that changes in microRNA expression in patient leukocytes contribute to CFS/ME pathology, and may therefore represent useful diagnostic biomarkers that can be detected in the peripheral blood of CFS/ME patients.miRNA expression in peripheral blood mononuclear cells (PBMC) from CFS/ME patients and healthy controls was analysed using the Ambion Bioarray V1. miRNA demonstrating differential expression were validated by qRT-PCR and then replicated in fractionated blood leukocyte subsets from an independent patient cohort. The CFS/ME associated miRNA identified by these experiments were then transfected into primary NK cells and gene expression analyses conducted to identify their gene targets.Microarray analysis identified differential expression of 34 miRNA, all of which were up-regulated. Four of the 34 miRNA had confirmed expression changes by qRT-PCR. Fractionating PBMC samples by cell type from an independent patient cohort identified changes in miRNA expression in NK-cells, B-cells and monocytes with the most significant abnormalities occurring in NK cells. Transfecting primary NK cells with hsa-miR-99b or hsa-miR-330-3p, resulted in gene expression changes consistent with NK cell activation but diminished cytotoxicity, suggesting that defective NK cell function contributes to CFS/ME pathology.This study demonstrates altered microRNA expression in the peripheral blood mononuclear cells of CFS/ME patients, which are potential diagnostic biomarkers. The greatest degree of miRNA deregulation was identified in NK cells with targets consistent with cellular activation and altered effector function
Modulation of delayed fluorescence pathways via rational molecular engineering
One of the key challenges in developing efficient organic light-emitting diodes (OLEDs) is overcoming the loss channel of triplet excitons. A common approach to mitigate these losses to enhance the external quantum efficiency of OLEDs is employing emitter molecules optimized for thermally activated delayed fluorescence (TADF) or triplet-triplet annihilation (TTA). However, achieving both in the solid state from the same organic chromophore poses a formidable challenge due to energetic and structural requirements needing to be met simultaneously. Here, we demonstrate TADF and TTA in donor-acceptor phthalimide derivatives by employing triphenylamine (TPA) or phenyl carbazole (PhCz) as a donor. Thin films of the TPA-substituted phthalimides doped in the poly(methyl methacrylate) matrix exhibit TADF emission from the singlet charge-transfer (CT) state. On the contrary, PhCz-substituted emitters display dominant TTA-induced delayed fluorescence in the neat film due to long-range molecular ordering that facilitates efficient triplet diffusion. The present study provides insight into how dual TADF-TTA delayed fluorescence can be realized in thin films of molecular semiconductors via rational molecular design
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Colour Peak:An analogue environment for the waters of late Noachian Mars
The surface of Mars cannot sustain liquid water today, but there is evidence water was present during the Noachian era. The transition of the martian climate from the wet Noachian to the dry Hesperian would have resulted in saline and sulfur rich surface waters . Terrestrial analogue environments that possess a chemistry like these proposed waters can be used to develop an understanding of organisms that could have persisted under such conditions. Here we present the chemistry and microbiome of the analogue environment Colour Peak, a sulfidic and saline spring system located within the Canadian High Arctic.
In this study, molecular and geochemical techniques were used to investigate the sediment of the Colour Peak springs. Nucleic acids were extracted from the microbes in the sediments and the microbiome was characterised by the amplification and sequencing of 16S rRNA gene amplicons. The elemental composition of the fluids and sediment was determined by ICP-OES and compared with brines determined from the chemistry of the “Rocknest” sand sample at Yellowknife Bay, Gale Crater (Mars) by thermochemical modelling. Gibbs energy values were calculated from this fluid chemistry to identify potentially viable metabolisms.
Analysis of the chemistries of the Colour Peak fluids confirmed a chemical composition like the thermochemically modelled fluid, with this justifying the classification of Colour Peak as an appropriate analogue environment to investigate the habitability of former martian aqueous environments. 16S rRNA gene profiling of the Colour Peak microbial community revealed it was dominated by bacteria associated with oxidation of reduced sulfur species and carbon dioxide fixation. Gibbs energy values calculated using the chemistry of the modelled martian fluid demonstrated that the oxidation of reduced sulfur species was also viable in this chemical environment under aerobic and anaerobic conditions. These results demonstrate that microbial sulfide oxidation is thermodynamically viable using both modelled and environmental proxies for former martian aqueous environments.
This study highlights that metabolisms utilising the oxidation of reduced sulfur species could have been thermodynamically viable in ancient martian aqueous environments. Further work is needed to assess this proposed viability and the potential for unambiguous biosignature formation
Characterisation of dust emissions from machined engineered stones to understand the hazard for accelerated silicosis
Engineered stones are novel construction materials associated with a recent upsurge in silicosis cases among workers in the stonemason industry. In order to understand the hazard for the short latency of lung disease among stonemasons, we simulated real-time dust exposure scenario by dry-machining engineered stones in controlled conditions, capturing and analysing the respirable dust generated for physical and chemical characteristics. Natural granite and marble were included for comparison. Cutting engineered stones generated high concentrations of very fine particles ( 80% respirable crystalline silica content, in the form of quartz and cristobalite. Engineered stones also contained 8–20% resin and 1–8% by weight metal elements. In comparison, natural stones had far lower respirable crystalline silica (4- 30%) and much higher metal content, 29–37%. Natural stone dust emissions also had a smaller surface area than engineered stone, as well as lower surface charge. This study highlighted the physical and chemical variability within engineered stone types as well as between engineered and natural stones. This information will ultimately help understand the unique hazard posed by engineered stone fabrication work and help guide the development of specific engineering control measures targeting lower exposure to respirable crystalline silica.Chandnee Ramkissoon, Sharyn Gaskin, Leigh Thredgold, Tony Hall, Shelley Rowett, Richard Gu
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The identification of sulfide oxidation as a potential metabolism driving primary production on late Noachian Mars
The transition of the martian climate from the wet Noachian era to the dry Hesperian (4.1–3.0 Gya) likely resulted in saline surface waters that were rich in sulfur species. Terrestrial analogue environments that possess a similar chemistry to these proposed waters can be used to develop an understanding of the diversity of microorganisms that could have persisted on Mars under such conditions. Here, we report on the chemistry and microbial community of the highly reducing sediment of Colour Peak springs, a sulfidic and saline spring system located within the Canadian High Arctic. DNA and cDNA 16S rRNA gene profiling demonstrated that the microbial community was dominated by sulfur oxidising bacteria, suggesting that primary production in the sediment was driven by chemolithoautotrophic sulfur oxidation. It is possible that the sulfur oxidising bacteria also supported the persistence of the additional taxa. Gibbs energy values calculated for the brines, based on the chemistry of Gale crater, suggested that the oxidation of reduced sulfur species was an energetically viable metabolism for life on early Mar
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