Abstract: An apparatus is provided for automatically constructing a polypeptide of high purity, up to 50 amino acids in length, using only single couplings. The apparatus includes an activation system for receiving protected amino acids, one kind at a time, having a common vessel (an activator vessel) in which to activate each of the amino acids. Also included is a reaction vessel for containing a resin used in solid-phase peptide synthesis for attaching a peptide chain thereto. A transfer system is also provided, which operates under control of a computer, to transfer the activated species from the activation system to the reaction vessel and to transfer amino acids, reagents, gases, and solvents from one part of the apparatus to another.

Abstract: A device is provided for measuring the concentration of oxygen in a sample utilizing the differential absorption by oxygen (O.sub.2) of two closely spaced ultraviolet (UV) radiation lines. The two UV lines are preferably isotope-shifted Hg lines in the vicinity of the Hg atomic transistion line at 1849.5A.

Abstract: A gas analyzer is provided which is particularly suited for making transcutaneous measurement of the CO.sub.2 concentration in the blood.In accordance with one embodiment of the invention, sample gases from the body are circulated in a cavity of the device. A rotating wheel in the cavity includes two reference cells and a sample cell which are sequentially rotated into the optical path between a source and a detector. Three signals are thereby provided which may be combined to give an output indication of the CO.sub.2 concentration in the body fluids. In a preferred embodiment, the sample cell is an "inverted cell" being in open communication with the sample gas circulating in the device so that the gas in the sample cell is a portion of the circulating gas which also surrounds the two reference cells. An output indication is thereby obtained which is insensitive to contaminants in the sample.

Abstract: A gas analyzer is provided which is particularly suited for making transcutaneous measurement of the CO.sub.2 concentration in the blood.In accordance with one embodiment of the invention, sample gases from the body are circulated in a cavity of the device. A rotating wheel in the cavity includes two reference cells and a sample cell which are sequentially rotated into the optical path between a source and a detector. Three signals are thereby provided which may be combined to give an output indication of the CO.sub.2 concentration in the body fluids. In a preferred embodiment, the sample cell is an "inverted cell" being in open communication with the sample gas circulating in the device so that the gas in the sample cell is a portion of the circulating gas which also surrounds the two reference cells. An output indication is thereby obtained which is insensitive to contaminants in the sample.