MicroLab

Function Immersion Oil contributes to two characteristics of the image viewed through the microscope: finer resolution and brightness. These characteristics are most critical under high magnification; so it is only the higher power, short focus, objectives that are usually designed for oil immersion.

Bright field microscopy is the simplest of all the optical microscopy illumination techniques. Sample illumination is transmitted (i.e., illuminated from below and observed from above) white light. The most common use of the microscope involves the use of an organism mounted to a glass microscope slide.

Phase contrast microscopy is an optical microscopy illumination technique in which small phase shifts in the light passing through a transparent specimen are converted into amplitude or contrast changes in the image.

A phase contrast microscope does not require staining to view the slide. This type of microscope made it possible to study the cell cycle.

Classical interference microscopy (also referred to as quantitative interference microscopy) uses two separate light beams with much greater lateral separation than that used in phase contrast microscopy or in differential interference microscopy (DIC).

Dark field microscopy (dark ground microscopy) describes microscopy methods, in both light and electron microscopy, which exclude the unscattered beam from the image. As a result, the field around the specimen (i.e. where there is no specimen to scatter the beam) is generally dark.

Interference microscopy

(Science: procedure) Although all image formation depends on interference, the term is generally restricted to systems in which contrast comes from the recombination of a reference beam with light that has been retarded by passing through the object. Because the phase retardation is a consequence of the difference in refractive index between specimen and medium and because the the refractive increment is almost the same for all biological molecules, it is possible to measure the amount of dry Mass per unit area of the specimen by measuring the phase retardation. Quantification of the phase retardation is usually done by using a compensator to reduce the bright object to darkness (see Senarmont and Ehrlinghaus compensators). Two major optical systems have been used the Jamin Lebedeff system and the mach zehnder system. These instruments are often referred to as interferometers, since they are designed for measuring phase retardation. Although their use has passed out of fashion, it may be that they will be employed more frequently in future in conjunction with image analysing systems.

An electron microscope is a type of microscope that uses a particle beam of electrons to illuminate a specimen and create a highly-magnified image. The electron microscope uses electrostatic and electromagnetic lenses in forming the image by controlling the electron beam to focus it at a specific plane relative to the specimen.

Y?Methyl violet is the main ingredient in Gram's stain used to ID bacteria. Gram-positive bacteria have a thick mesh-like cell wall made of peptidoglycan (90 % of cell wall), which stain purple and Gram-negative bacteria have a thinner layer (10% of cell wall), which stain pink

Staining affinity?A modified Papanicolaou staining procedure using diluted Harris' hematoxylin with potassium alum is described. Nucleolar staining varies from blue to bright red. This technique has been applied to mammary tumor cell lines in vitro under several conditions of hormonal stimulation known to induce protein synthesis and cell differentiation. Blue nucleoli are observed in control resting cells, while bright red nucleoli are seen after hormonal stimulation.