Abstract: The method is for quantitative measurement of particle content using hydrated state imaging such as CryoTEM. A sample of virus-like particles (VLPs) or virus particles is provided. Preferably, the sample is rapidly frozen into a cryogenic liquid at a cryogenic temperature. While at the cryogenic temperature, the particle content of each VLP in the frozen sample is observed in the CryoTEM. An amount of the particle content of the VLPs is determined to assess whether the VLPs are empty or not.

Abstract: The method is for quantitative measurement of particle content using hydrated state imaging such as CryoTEM. A sample of virus-like particles (VLPs) or virus particles is provided. Preferably, the sample is rapidly frozen into a cryogenic liquid at a cryogenic temperature. While at the cryogenic temperature, the particle content of each VLP in the frozen sample is observed in the CryoTEM. An amount of the particle content of the VLPs is determined to assess whether the VLPs are empty or not.

Abstract: The method is for quantification of sub-visible particles. A filter membrane is provided that has a plurality of pores defined therethrough. The pores are sealed with a sealant such as glycine or poly-vinyl alcohol (PVA). A sample droplet, containing liquid and sub-visible particles, is applied onto the filter membrane. The liquid dissolves the sealant in pores disposed directly below the sample droplet. The liquid flows through the pores in which the sealant has been dissolved and the sub-visible particles remain on top of the filter membrane. The particles are enumerated in an electron microscope.

Abstract: The method is for quantitative measurement of particle content using hydrated state imaging such as CryoTEM. A sample of virus-like particles (VLPs) or virus particles is provided. Preferably, the sample is rapidly frozen into a cryogenic liquid at a cryogenic temperature. While at the cryogenic temperature, the particle content of each VLP in the frozen sample is observed in the CryoTEM. An amount of the particle content of the VLPs is determined to assess whether the VLPs are empty or not.

Abstract: The method is for quantification of sub-visible particles. A filter membrane is provided that has a plurality of pores defined therethrough. The pores are sealed with a sealant such as glycine or poly-vinyl alcohol (PVA). A sample droplet, containing liquid and sub-visible particles, is applied onto the filter membrane. The liquid dissolves the sealant in pores disposed directly below the sample droplet. The liquid flows through the pores in which the sealant has been dissolved and the sub-visible particles remain on top of the filter membrane. The particles are enumerated in an electron microscope.

Abstract: The method is for quantification of sub-visible particles. A filter membrane is provided that has a plurality of pores defined therethrough. The filter membrane is in operational engagement with a vacuum chamber. The pores are sealed with a sealant. A sample droplet, containing a liquid and sub-visible particles, is applied onto the filter membrane. The liquid dissolves the sealant in pores disposed directly below the sample droplet. The liquid flows through the pores in which the sealant has been dissolved and the sub-visible particles remain on top of the filter membrane. The particles are enumerated in an electron microscope.

Abstract: The method is for quantification of sub-visible particles. A filter membrane is provided that has a plurality of pores defined therethrough. The filter membrane is in operational engagement with a vacuum chamber. The pores are sealed with a sealant. A sample droplet, containing a liquid and sub-visible particles, is applied onto the filter membrane. The liquid dissolves the sealant in pores disposed directly below the sample droplet. The liquid flows through the pores in which the sealant has been dissolved and the sub-visible particles remain on top of the filter membrane. The particles are enumerated in an electron microscope.

Abstract: The method is for quantification of sub-visible particles. A filter membrane is provided that has a plurality of pores defined therethrough. The filter membrane is in operational engagement with a vacuum chamber. The pores are sealed with a sealant. A sample droplet, containing a liquid and sub-visible particles, is applied onto the filter membrane. The liquid dissolves the sealant in pores disposed directly below the sample droplet. The liquid flows through the pores in which the sealant has been dissolved and the sub-visible particles remain on top of the filter membrane. The particles are enumerated in an electron microscopy.

Abstract: The method is for quantification of sub-visible particles. A filter membrane is provided that has a plurality of pores defined therethrough. The filter membrane is in operational engagement with a vacuum chamber. The pores are sealed with a sealant. A sample droplet, containing a liquid and sub-visible particles, is applied onto the filter membrane. The liquid dissolves the sealant in pores disposed directly below the sample droplet. The liquid flows through the pores in which the sealant has been dissolved and the sub-visible particles remain on top of the filter membrane. The particles are enumerated in an electron microscopy.

Abstract: The method is for automatic astigmatism correction of a lens system. A first image of a first frequency spectrum in a microscope is provided. The first image of a view is not in focus. The first image is then imaged. A first roundness measure of a distribution and directions of intensities in the first image is determined. The lens is changed to a second stigmator setting to provide a second image of a second frequency spectrum. The second image of the view is not in focus. The second image is the same view as the first image of the view at the first stigmator setting. A second roundness measure of a distribution and directions of intensities in the second image is determined. The first roundness measure is compared with the second roundness measure. The image with the roundness measure indicating the roundest distribution is selected.

Abstract: The method is for automatic astigmatism correction of a lens system. A first image of a first frequency spectrum in a microscope is provided. The first image of a view is not in focus. The first image is then imaged. A first roundness measure of a distribution and directions of intensities in the first image is determined. The lens is changed to a second stigmator setting to provide a second image of a second frequency spectrum. The second image of the view is not in focus. The second image is the same view as the first image of the view at the first stigmator setting. A second roundness measure of a distribution and directions of intensities in the second image is determined. The first roundness measure is compared with the second roundness measure. The image with the roundness measure indicating the roundest distribution is selected.

Abstract: The method is for automatic astigmatism correction of a lens system. A first image is provided that is not in focus at a first stigmator setting of a set of lenses. A calculating device calculates a corresponding first Fourier spectrum image. A distribution and direction of pixels of the Fourier spectrum image are determined by calculating a first vector and a second vector. The first vector is compared with the second vector. The lens system is changed from a first stigmator setting to a second stigmator setting to provide a second image. A corresponding Fourier spectrum image is calculated. The distribution and direction of pixels of the second Fourier spectrum image is determined by calculating a third vector and a fourth vector. The third vector is compared to the fourth vector. The image that has the lowest vector ratio is selected.

Abstract: The method is for automatic astigmatism correction of a lens system. A first image is provided that is not in focus at a first stigmator setting of a set of lenses. A calculating device calculates a corresponding first Fourier spectrum image. A distribution and direction of pixels of the Fourier spectrum image are determined by calculating a first vector and a second vector. The first vector is compared with the second vector. The lens system is changed from a first stigmator setting to a second stigmator setting to provide a second image. A corresponding Fourier spectrum image is calculated. The distribution and direction of pixels of the second Fourier spectrum image is determined by calculating a third vector and a fourth vector. The third vector is compared to the fourth vector. The image that has the lowest vector ratio is selected.