Direct measurement of hydrogen bonding in DNA nucleotide bases by atomic force microscopy.

We have used self-assembled purines and pyrimidines on planar gold surfaces and on gold-coated atomic force microscope (AFM) tips to directly probe intermolecular hydrogen bonds. Electron spectroscopy for chemical analysis (ESCA) and thermal programmed desorption (TPD) measurements of the molecular layers suggested monolayer coverage and a desorption energy of about 25 kcal/mol. Experiments were performed under water, with all four DNA bases immobilized on AFM tips and flat surfaces. Directional hydrogen-bonding interaction between the tip molecules and the surface molecules could be measured only when opposite base-pair coatings were used. The directional interactions were inhibited by excess nucleotide base in solution. Nondirectional van der Waals forces were present in all other cases. Forces as low as two interacting base pairs have been measured. With coated AFM tips, surface chemistry-sensitive recognition atomic force microscopy can be performed.

The entomologist's useful compendium; or, An introduction to the knowledge of British insects, comprising the best means of obtaining and preserving them, and a description of the apparatus generally used; together with the genera of Linné, and the modern method of arranging the classes...according to the views of Dr. Leach...with instructions for collecting and fitting up objects for the microscope.

1821

Evenings at the microscope : or, Researches among the minuter organs and forms of animal life /

Originally published in London, 1859.

The romance of the microscope; an interesting description of its uses in all branches of science, industry, agriculture, and in the detection of crime, with a short account of its origin, history & development.

Mode of access: Internet.

The microscope made easy : or, I. The nature, uses and magnifying powers of the best kinds of microscopes described ... II. An account of what surprizing discoveries have been already made by the microscope ... /

Mode of access: Internet.

The Microscope.

Later published in Trenton, N.J.

Sept objets regardés au microscope. Exposé de quelques principes de la microscopie.

T-p. and parrallel text in Dutch.

New approaches in correlative studies of biological ultrastructure by high-resolution electron microscopy.

Paper presented at Royal Microscopical Society's celebration of the "Tercentenary of the Microscope in Living Biology," April 9, 1963, Bethesda, Maryland.

Investigation of solid surfaces by field emission microscopy and mass spectrometry; final report.

"Contract no. AF 49 (638)-748. Division file 30-4. AFOSR-2273."

Optic projection : principles, installation, and use of the magic lantern, projection microscope, reflection lantern moving picture machine, fully illustrated with plates and with over 400 text-figures /

Bibliography: p. 693-703.

Employment for the microscope. /

Mode of access: Internet.

The microscope : an introduction to microscopic methods and to histology /

"This edition is practically unchanged from the 10th ed., pub. in 1908."