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S. cerevisiae cells imaged by DIC microscopy A quantitative phase-contrast microscopy image of cells in culture. The height and color of an image point correspond to the optical thickness, which only depends on the object's thickness and the relative refractive index. The volume of an object can thus be determined when the difference in ...
A scanning transmission electron microscope (STEM) is a type of transmission electron microscope (TEM). Pronunciation is [stɛm] or [ɛsti:i:ɛm]. As with a conventional transmission electron microscope (CTEM), images are formed by electrons passing through a sufficiently thin specimen. However, unlike CTEM, in STEM the electron beam is focused ...
Step-by-step video and audio instructions on how to prepare a wet mount specimen of eukaryotic animal cells; specifically Human epithelial cells from the inside of the cheek. Video by Tami (Guy) Port, Chief Executive Nerd at ScienceProfOnline.com.
A scanning electron microscope (SEM) is a type of electron microscope that produces images of a sample by scanning the surface with a focused beam of electrons. The electrons interact with atoms in the sample, producing various signals that contain information about the surface topography and composition of the sample.
Antonie van Leeuwenhoek (1632–1723). The field of microscopy (optical microscopy) dates back to at least the 17th-century.Earlier microscopes, single lens magnifying glasses with limited magnification, date at least as far back as the wide spread use of lenses in eyeglasses in the 13th century [2] but more advanced compound microscopes first appeared in Europe around 1620 [3] [4] The ...
A visualization of negative staining (a) and positive staining (b) of samples in transmission electron microscopy. The top row is a side profile of the sample, the bottom row shows the resulting image from the microscope. A section of a cell of Bacillus subtilis, taken with a Tecnai T-12 TEM. The scale bar is 200 nm.
Above the sample, the wave of an electron can be approximated as a plane wave incident on the sample surface. As it penetrates the sample, it is attracted by the positive atomic potentials of the atom cores, and channels along the atom columns of the crystallographic lattice (s-state model [4]).
Keratinization is the differentiation of keratinocytes in the stratum granulosum into nonvital surface cells or squames to form the stratum corneum. The cells terminally differentiate as they migrate to the surface from the stratum basale where the progenitor cells are located to the superficial surface.