Christopher C Bull

US Patent:

55830471, Dec 10, 1996

Filed:

Apr 22, 1994

Appl. No.:

8/231411

Inventors:

Thomas A. Blinka - Columbia MD
Christopher Bull - Bethesda MD
Charles R. Barmore - Moore SC
Drew V. Speer - Columbia MD

Assignee:

W. R. Grace & Co.-Conn. - New York NY

International Classification:

G01N 3100

US Classification:

436 5

Abstract:

A method of detecting the permeability of an article to oxygen is disclosed. A fluorescent redox indicator, preferably riboflavin, is dispersed in a carrier and placed on an impermeable substrate. The article to be measured is placed adjacent to the carrier. Residual oxygen is removed, the redox indicator is photoreduced, the article and carrier are exposed to oxygen, and the indicator is exposed to UV light.

US Patent:

51027925, Apr 7, 1992

Filed:

Aug 13, 1987

Appl. No.:

7/084782

Inventors:

James F. Walter - Ashton MD
Christopher Bull - Bethesda MD

Assignee:

W. R. Grace & Co.-Conn. - New York NY

International Classification:

C12P 1306

US Classification:

435116

Abstract:

L-Serine derivatives produced by the enzyme catalyzed aldol condensation of glycine and an aldehyde in aqueous solution are recovered in high yield by extracting the aqueous product solution containing said serine derivatives with an organic phase comprising (i) an aldehyde, or (ii) mixtures of an aldehyde and a water immiscible organic solvent, followed by re-extracting the organic phase with an aqueous phase having a pH of less than about 7. The L-erythro isomers of L-serine derivatives such as L-phenylserine may be preferentially prepared by the use of this extraction/re-extraction procedure in combination with bioreactor reaction conditions which include a pH of from about 7. 5 to 10, an aldehyde concentration of from about 1 to about 90 grams/liter, a glycine concentration of from about 10 to about 300 grams/liter, and a molar ratio of glycine to aldehyde of from about 4:1 to about 100:1.