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Advanced Condenser Systems: Abbe CondensersDDT CrystallitesThe images below compare performance of the Intel Play QX3 Computer Microscope with and without the aid of an organized cone of illumination from a simple two-lens Abbe substage condenser containing an aperture diaphragm. These photomicrographs are unretouched and were captured with the QX3 interactive software. This organochlorine insecticide can be considered as the pesticide of the greatest historical significance, due to its effect on the environment, agriculture, and human health. First synthesized by a German graduate student in 1873, it was rediscovered by Dr. Paul Mueller, a Swiss entomologist, in 1939 while searching for a long-lasting insecticide for the clothes moth. DDT subsequently proved to be extremely effective against flies and mosquitoes, ultimately leading to the award of the Nobel Prize in medicine for Dr. Mueller in 1948. Effective January 1, 1973 the Environmental Protection Agency (EPA) officially canceled all uses of DDT, but not before more than 1 billion kilograms of DDT had been introduced into the United States. Like Endosulfan, DDT disrupts the delicate balance of sodium and potassium within neurons. The pesticide is effective against a wide spectrum of insects in the agricultural arena and also mosquitoes that transmit malaria and yellow fever as well as body lice that carry typhus. Birefringent DDT CrystallitesThe images above were recorded using the Intel Play QX3 microscope in transmitted brightfield mode equipped with crossed polarizers and a full-wave retardation plate. On the top is a digital image from a stock QX3 microscope using auxiliary illumination provided by a fiber optic light pipe through a hole drilled into the mixing chamber. The image on the bottom was recorded using the QX3 microscope body and a simple two-lens Abbe low numerical aperture substage condenser. BACK TO ABBE CONDENSER POLARIZED GALLERY Questions or comments? Send us an email.© 1995-2022 by Michael W. Davidson and The Florida State University. All Rights Reserved. No images, graphics, software, scripts, or applets may be reproduced or used in any manner without permission from the copyright holders. Use of this website means you agree to all of the Legal Terms and Conditions set forth by the owners.
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