This study evaluated the allergen impermeability against airborne allergens of dust mite droppings through all parts of commercial bed covers, including surface seams and zippers. Specimens were taken from places with...This study evaluated the allergen impermeability against airborne allergens of dust mite droppings through all parts of commercial bed covers, including surface seams and zippers. Specimens were taken from places with and without seams and zipper. A novel penetration cell was developed to expose the specimens to an inoculum of purified mite droppings that was assessed for its allergen content Der p1 prior to the penetration tests. Using covers of different construction and material, the penetration level increased significantly in the presence of seams and zippers and could reach up to 6% depending on the seam’s/zipper’s characteristics and quality. Therefore, zippers and seams have to be considered as access points for the penetration of mite droppings. As for the penetration of airborne mite particles through the zipper, the penetration level was greatly attenuated by the presence of a cover strip. Depending on the respective quality and the construction type, the mite allergen Der p1 penetrated most likely through the zipper and seams of the specimens, already after a single laundry cycle. Hence, laundry may compromise the barrier performance and proves to be an important quality feature. In all samples, the textile surface showed sufficient allergen impermeability. Our conclusions provide recommendations to both manufacturers and users.展开更多
We introduce voltage-contrast scanning electron microscopy(VC-SEM)for visual characterization of the electronic properties of single-walled carbon nanotubes.VC-SEM involves tuning the electronic band structure and ima...We introduce voltage-contrast scanning electron microscopy(VC-SEM)for visual characterization of the electronic properties of single-walled carbon nanotubes.VC-SEM involves tuning the electronic band structure and imaging the potential profi le along the length of the nanotube.The resultant secondary electron contrast allows to distinguish between metallic and semiconducting carbon nanotubes and to follow the switching of semiconducting nanotube devices,as confi rmed by in situ electrical transport measurements.We demonstrate that high-density arrays of individual nanotube devices can be rapidly and simultaneously characterized.A leakage current model in combination with fi nite element simulations of the device electrostatics is presented in order to explain the observed contrast evolution of the nanotube and surface electrodes.This work serves to fi ll a void in electronic characterization of molecular device architectures.展开更多
文摘This study evaluated the allergen impermeability against airborne allergens of dust mite droppings through all parts of commercial bed covers, including surface seams and zippers. Specimens were taken from places with and without seams and zipper. A novel penetration cell was developed to expose the specimens to an inoculum of purified mite droppings that was assessed for its allergen content Der p1 prior to the penetration tests. Using covers of different construction and material, the penetration level increased significantly in the presence of seams and zippers and could reach up to 6% depending on the seam’s/zipper’s characteristics and quality. Therefore, zippers and seams have to be considered as access points for the penetration of mite droppings. As for the penetration of airborne mite particles through the zipper, the penetration level was greatly attenuated by the presence of a cover strip. Depending on the respective quality and the construction type, the mite allergen Der p1 penetrated most likely through the zipper and seams of the specimens, already after a single laundry cycle. Hence, laundry may compromise the barrier performance and proves to be an important quality feature. In all samples, the textile surface showed sufficient allergen impermeability. Our conclusions provide recommendations to both manufacturers and users.
基金The research was funded by the Initiative and Networking Fund of the Helmholtz Gemeinschaft Deutscher Forschungszentren and equipment grant from Agilent Technologies.
文摘We introduce voltage-contrast scanning electron microscopy(VC-SEM)for visual characterization of the electronic properties of single-walled carbon nanotubes.VC-SEM involves tuning the electronic band structure and imaging the potential profi le along the length of the nanotube.The resultant secondary electron contrast allows to distinguish between metallic and semiconducting carbon nanotubes and to follow the switching of semiconducting nanotube devices,as confi rmed by in situ electrical transport measurements.We demonstrate that high-density arrays of individual nanotube devices can be rapidly and simultaneously characterized.A leakage current model in combination with fi nite element simulations of the device electrostatics is presented in order to explain the observed contrast evolution of the nanotube and surface electrodes.This work serves to fi ll a void in electronic characterization of molecular device architectures.
