222 research outputs found

    The Impact of \u3ci\u3emsaABCR\u3c/i\u3e On \u3ci\u3esarA\u3c/i\u3e-Associated Phenotypes is Different in Divergent Clinical Isolates of \u3ci\u3eStaphylococcus aureus\u3c/i\u3e

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    The staphylococcal accessory regulator (sarA) plays an important role in Staphylococcus aureus infections including osteomyelitis, and the msaABCR operon has been implicated as an important factor in modulating expression of sarA. Thus, we investigated the contribution of msaABCR to sarA-associated phenotypes in the S. aureus clinical isolates LAC and UAMS-1. Mutation of msaABCR resulted in reduced production of SarA and a reduced capacity to form a biofilm in both strains. Biofilm formation was enhanced in a LAC msa mutant by restoring the production of SarA, but this was not true in a UAMS-1 msa mutant. Similarly, extracellular protease production was increased in a LAC msa mutant but not a UAMS-1 msa mutant. This difference was reflected in the accumulation and distribution of secreted virulence factors and in the impact of extracellular proteases on biofilm formation in a LAC msa mutant. Most importantly, it was reflected in the relative impact of mutating msa as assessed in a murine osteomyelitis model, which had a significant impact in LAC but not in UAMS-1. In contrast, mutation of sarA had a greater impact on all of these in vitro and in vivo phenotypes by comparison to mutation of msaABCR, and it did so in both LAC and UAMS-1. These results suggest that, at least in osteomyelitis, it would be therapeutically preferable to target sarA rather than msaABCR to achieve the desired clinical result, particularly in the context of divergent clinical isolates of S. aureus

    Aristolactama y esteróles del tallo de piper chiadoense

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    Del extracto etanólico del tallo de Piper chiadoense Junker (Piperaceae) fueron aislados por métodos cromatográficos la aristolactama identificada como lactama del ácido 10-amino-3,4-dimetoxifenantreno-l carboxílico (cepharanone B); campesterol; estigmasterol y B-sitosterol. Sus estructuras fueron determinadas por métodos espectroscópicos y por comparación con datos reportados en la literatura

    Methane Emissions from Livestock Slurry: Effects of Storage Temperature and Changes in Chemical Composition

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    Livestock production contributes to releasing methane into the atmosphere. Liquid manure management offers significant opportunities to reduce these emissions. A better understanding of the factors controlling methane emissions from manure is necessary to select effective mitigation strategies. Our study aimed to identify the influence of storage temperature and the associated change in chemical composition on methane emissions from dairy and fattening pig manure. Storage temperature affects microbial activity and induces changes in chemical composition that are key influences in methane emissions. Dairy and fattening pig manure samples were stored at five different temperatures (5–25 °C) for 90 days in a laboratory-scale experiment to measure the methane production. The chemical composition of the slurry samples was analyzed, and the biochemical methane potential (BMP) tests were performed before and after storage. For pig manure stored at 25 °C and 20 °C, methane emissions accounted for 69.3% and 50.3% of the BMP, respectively. Maximum methane emissions for dairy slurry were observed at 25 °C but remained at a low level. Analyses of the accumulation of volatile fatty acids (VFAs) during storage are presented in few studies, this work revealed a potential inhibition of methane production, where the accumulation of VFAs was most elevated in samples stored at 20 °C and 25 °C. This partly counteracted the increase in methane emissions expected from the higher temperatures. The degree of VFA and dissociated fatty acids accumulation in dairy cattle slurry should be assessed for more accurate estimations of methane emissions from slurry stores

    Workshop on dynamics of land to lake transfers in the Winam Gulf

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    This report describes a stakeholder engagement workshop carried out by the British Geological Survey (BGS) and research partners from the University of Eldoret and the Kenya Marine and Fisheries Research Institute in December 2023. This workshop was co-funded by a Royal Society International Collaboration Grant (ICA\R1\191077 entitled ‘Dynamics of Environmental Geochemistry and Health in a Lake-wide Basin’) and a NERC NC-International grant (NE/X006255/1, entitled ‘Geoscience to tackle global environmental challenges’). The aim of this workshop was to disseminate our most recent research findings on soil erosion and sediment source apportionment in the Winam Gulf, Kenya. We also built upon previous stakeholder engagement meetings where discussions were held to identify the most effective methods of delivering outputs where they can be used to inform strategies to mitigate soil erosion and sediment transfers in the catchment resulting from poor land management. All the information collected from participants will be used to inform future workshops, planned for June 2024 and final data distribution tools. Furthermore, it was recommended by the workshop participants that the need for greater capacity building could be achieved through the formation of a committee which oversees and plans the coordination of land-lake activities through the communication and sharing of the latest activities, interests and needs of the combined land/lake communities in the Lake Victoria basin. The formation of such a committee could be facilitated through this research project and would be the first step towards creating an impactful management framework. This could provide an exemplar for other land-lake systems

    Quercetina 3-metileter de las hojas de phoebe cinnamomifolia

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    Investigaciones químicas de especies pertenecientes al géntro Phoebe, reportan el aislamiento de alcaloides aporfínicos y oxoaporfínicos (1). Phoebe cinnamomifolia es una especie arbórea de las regiones Andina y Amazónica de Colombia; de su corteza se aislaron e identificaron (-) epicatequina; proantocianidina B2; pVoantocianidina B4 y a-farneseno (2) y de la madera 1,2,3,9,10-entametoxioxoaporfina; 1,2,9,10-tetrametoxioxoaporfina; sitosterol; n-tetracosanol y los ácidos cáprico; oleico; behénico; araquídico y esteárico (1). Del extracto etanólico de las hojas de P. cinnamomifolia, se estudió el residuo insoluble en éter de petróleo-acetato de etilo (9:1) dando como compuesto mayoritario quercetina 3-metil éter 1 y alcaloides oxoaporfínicos no identificados

    Estudio químico de piper steerni1

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    Del extracto clorofórmico de las hojas de Piper steerni se aislaron por métodos cromatográficos 5,7-dihidroxyflavanona, 5-hidroxi-7-metoxinavona y P-sitosterol; cl extracto en acetato de etilo del tallo del mismo vegetal presentó iguales constituyentes que las hojas junto con bases nitrogenadas de las cuales se identificó N-(4-hidroxifcniletilen) cinamamida como un nuevo compuesto en la familia Piperaceae. Los metabolitos secundarios mayoritarios del aceite esencial de las hojas de P. steerni fueron caracterizados como benzaldehido, alcohol bencílico y benzoato de etilo. Las estructuras de los compuestos fueron establecidas por métodos quimicos y espectroscópicos y por correlaciones con substancias conocidas

    Precipitation mediates sap flux sensitivity to evaporative demand in the neotropics

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    Transpiration in humid tropical forests modulates the global water cycle and is a key driver of climate regulation. Yet, our understanding of how tropical trees regulate sap flux in response to climate variability remains elusive. With a progressively warming climate, atmospheric evaporative demand [i.e., vapor pressure deficit (VPD)] will be increasingly important for plant functioning, becoming the major control of plant water use in the twenty-first century. Using measurements in 34 tree species at seven sites across a precipitation gradient in the neotropics, we determined how the maximum sap flux velocity (vmax) and the VPD threshold at which vmax is reached (VPDmax) vary with precipitation regime [mean annual precipitation (MAP); seasonal drought intensity (PDRY)] and two functional traits related to foliar and wood economics spectra [leaf mass per area (LMA); wood specific gravity (WSG)]. We show that, even though vmax is highly variable within sites, it follows a negative trend in response to increasing MAP and PDRY across sites. LMA and WSG exerted little effect on vmax and VPDmax, suggesting that these widely used functional traits provide limited explanatory power of dynamic plant responses to environmental variation within hyper-diverse forests. This study demonstrates that long-term precipitation plays an important role in the sap flux response of humid tropical forests to VPD. Our findings suggest that under higher evaporative demand, trees growing in wetter environments in humid tropical regions may be subjected to reduced water exchange with the atmosphere relative to trees growing in drier climates

    The legislative backgrounds of workplace health promotion in three European countries : A comparative analysis

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    Publisher Copyright: © 2015 Šidagytė et al.; licensee BioMed Central.Background: This article investigates the legal database and theoretical basis of workplace health promotion (WHP) in three European countries: Finland, Latvia and Lithuania, and aims to find insights into effective WHP implementation. Methods: In November 2013, a stakeholders' survey was carried out. The questionnaire included questions about legal documents and non-legislative measures relevant to WHP, institutions and other bodies/organizations working in the field, WHP conception/definition, and implementation of WHP activities according to the enterprises' size. Results: Only Finland has adopted a specific law on occupational health care (separate from occupational safety). ILO conventions No. 161 (Occupational Health Services Convention) and No. 187 (Promotional Framework for Occupational Safety and Health Convention) are ratified only in Finland. In Finland, the Ministry of Social Affairs and Health acts as one ministry, while two Baltic countries have two separate ministries (one for health and another for social affairs). None of the countries has legally approved a definition of WHP. Latvia and Lithuania tend to separate WHP from other activities, whereas Finland integrates WHP into other occupational health and safety elements. Conclusions: Finland has a more extensive legislative and organizational background to WHP than Latvia and Lithuania. In defining WHP, all the countries refer to the Luxembourg Declaration on Workplace Health Promotion in the European Union. Finland's practice of integrating WHP into other occupational health and safety elements is important.publishersversionPeer reviewe

    Feature Fusion of Raman Chemical Imaging and Digital Histopathology using Machine Learning for Prostate Cancer Detection

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    The diagnosis of prostate cancer is challenging due to the heterogeneity of its presentations, leading to the over diagnosis and treatment of non-clinically important disease. Accurate diagnosis can directly benefit a patient’s quality of life and prognosis. Towards addressing this issue, we present a learning model for the automatic identification of prostate cancer. While many prostate cancer studies have adopted Raman spectroscopy approaches, none have utilised the combination of Raman Chemical Imaging (RCI) and other imaging modalities. This study uses multimodal images formed from stained Digital Histopathology (DP) and unstained RCI. The approach was developed and tested on a set of 178 clinical samples from 32 patients, containing a range of non-cancerous, Gleason grade 3 (G3) and grade 4 (G4) tissue microarray samples. For each histological sample, there is a pathologist labelled DP - RCI image pair. The hypothesis tested was whether multimodal image models can outperform single modality baseline models in terms of diagnostic accuracy. Binary non-cancer/cancer models and the more challenging G3/G4 differentiation were investigated. Regarding G3/G4 classification, the multimodal approach achieved a sensitivity of 73.8% and specificity of 88.1% while the baseline DP model showed a sensitivity and specificity of 54.1% and 84.7% respectively. The multimodal approach demonstrated a statistically significant 12.7% AUC advantage over the baseline with a value of 85.8% compared to 73.1%, also outperforming models based solely on RCI and median Raman spectra. Feature fusion of DP and RCI does not improve the more trivial task of tumour identification but does deliver an observed advantage in G3/G4 discrimination. Building on these promising findings, future work could include the acquisition of larger datasets for enhanced model generalization
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