2,395 research outputs found

    Cytochrome P4501-inhibiting chemicals amplify aryl hydrocarbon receptor activation and IL-22 production in T helper 17 cells

    Get PDF
    The aryl hydrocarbon receptor (AHR)controls interleukin 22 production by T helper 17 cells (Th17). IL-22contributes to intestinalhomeostasis but has also been implicated inchronic inflammatory disorders and colorectal cancer, highlighting the need for appropriate regulation of IL-22 production. Upon activation, the AHR induces expression of cytochrome P4501 (CYP1) enzymes that in turn play an important feedback role that curtails the duration of AHR signaling by metabolizingAHRligands. Recently we described how agents that inhibit CYP1 function potentiate AHR signalingby disruptingmetabolic clearance of the endogenous ligand 6-formylindolo[3,2-b]carbazole (FICZ). In the present study, we investigated the immune-modulating effects of environmental pollutants such as polycyclic aromatic hydrocarbons on Th17 differentiation and IL-22 production. Using Th17 cells deficient in CYP1 enzymes (Cyp1a1/1a2/1b1-/-)we show that these chemicals potentiate AHR activation through inhibition of CYP1 enzymes which leads to increases in intracellular AHR agonists. Our findings demonstrate that IL-22 production by Th17 cellsis profoundly enhanced by impaired CYP1-function and strongly suggest that chemicals able to modify CYP1 function or expression may disrupt AHR-mediated immune regulation by altering the levels of endogenous AHR agonist(s)

    Creating space for biodiversity by planning swath patterns and field marging using accurate geometry

    Get PDF
    Potential benefits of field margins or boundary strips include promotion of biodiversity and farm wildlife, maintaining landscape diversity, exploiting pest predators and parasites and enhancing crop pollinator populations. In this paper we propose and demonstrate a method to relocate areas of sub-efficient machine manoeuvring to boundary strips so as to optimise the use of available space. Accordingly, the boundary strips will have variable rather than fixed widths. The method is being tested in co-operation with seven farmers in the Hoeksche Waard within the province of Zuid Holland, The Netherlands. In a preliminary stage of the project, tests were performed to determine the required accuracy of field geometry. The results confirmed that additional data acquisition using accurate measuring devices is required. In response, a local contracting firm equipped a small all-terrain vehicle (quad) with an RTK-GPS receiver and set up a service for field measurement. Protocols were developed for requesting a field measurement and for the measurement procedure itself. Co-ordinate transformation to a metric system and brute force optimization of swath patterns are achieved using an open source geospatial library (osgeo.ogr) and Python scripting. The optimizer basically tests all orientations and relevant intermediate angles of input field boundaries and tries incremental positional shifts until the most efficient swath pattern is found. Inefficient swaths intersecting boundary areas are deleted to create space for field margins. The optimised pattern can be forwarded to an agricultural navigation system. At the time of the conference, the approach will have been tested on several farm fields

    Towards a predictive understanding of direct ink writing of graphene-based inks

    Get PDF
    Direct ink writing (DIW) presents a flexible and resource-efficient approach towards the prototyping of functional materials and devices with complex shapes. Printed functional materials for electronic devices depend on conductive fillers such as graphene nanoplatelets (GNPs), which are increasingly popular in printed electronics and energy materials thanks to their low cost, non-toxicity and high specific surface area. However, non-spherical colloids with large filler-to-nozzle size ratios like GNPs present a challenge for high-resolution DIW due to risk of nozzle clogging. As DIW of platelet-based inks is gaining traction in several fields, the feasibility of high-resolution DIW of platelet-based inks is demonstrated here on the example of GNPs (&lt; 50 μm). A workflow for the combined optimization of ink rheology and printing process parameters was developed to gain a predictive understanding of filament quality and morphology. Using two inks and two nozzle diameters per ink, filaments ranging from &lt;100 – 1200 μm in width and 30 – 300 μm in height were produced, with conductivities suitable for application in sensors or electrodes. The derived predictive models were successfully deployed to predict filament dimensions and to achieve excellent print quality even for fine sub-nozzle size structures with very high filler-to-nozzle size ratios within only one iteration of the workflow. With this study, we advocate for the integrated development of materials for processes and processes for materials. This study will benefit high-resolution rapid prototyping of a large class of functional materials for wearable electronics, sensors, RF passives, energy materials and tissue engineering.</p
    corecore