James N Demas

Author:

James Demas

ISBN #:

0205123686

Author:

James Demas

ISBN #:

0205125514

US Patent:

7749765, Jul 6, 2010

Filed:

Aug 3, 2006

Appl. No.:

11/997630

Inventors:

James N. Demas - Charlottesville VA, US
Wenying Xu - Charlottesville VA, US

Assignee:

University of Virginia Patent Foundation - Charlottesville VA

International Classification:

G01N 33/20
B01J 13/02

US Classification:

436 77, 436 73, 436164, 436172, 210638, 210639, 2102133

Abstract:

The present invention provides compositions and methods for extracting, isolating, and measuring lead dissolved in aqueous solutions, including water.

US Patent:

50304208, Jul 9, 1991

Filed:

Feb 3, 1986

Appl. No.:

6/825735

Inventors:

John R. Bacon - Sylvan NC
James N. Demas - Charlottesville VA

Assignee:

University of Virginia Alumni Patents Foundation - Charlottesville VA

International Classification:

G01N 2164
G01N 2177

US Classification:

422 8207

Abstract:

Quenching luminescence of the tris(4,7-diphenyl-1,10-phenanthroline)ruthenium(II) perchorate, immobilized in a silicone rubber by oxygen is shown to be an accurate and precise method for measuring oxygen concentration in solutions and in the gas phase. Quenching can be quantitated by either lifetime or intensity quenching measurements. Strong aqueous acids and bases, complexing agents, oxidants, and reductants do not penetrate the hydrophobic polymer and, therefore, do not affect the response. Gaseous interferents, such as H. sub. 2 S, anesthesia gases (e. g. N. sub. 2 O, Halothane), and fluorocarbons do not affect the response. Chlorine and especially SO. sub. 2 cause strong, but reversible interference presumably because of electron transfer quenching. A system with a response time of less

US Patent:

58342044, Nov 10, 1998

Filed:

Dec 12, 1997

Appl. No.:

8/989509

Inventors:

Rhett L. Affleck - Los Alamos NM
W. Patrick Ambrose - Los Alamos NM
James N. Demas - Charlottesville VA
Peter M. Goodwin - Jemez Springs NM
Mitchell E. Johnson - Pittsburgh PA
Richard A. Keller - Los Alamos NM
Jeffrey T. Petty - Los Alamos NM
Jay A. Schecker - Sante Fe NM
Ming Wu - Los Alamos NM

Assignee:

The Regents of the University of California - Los Alamos NM

International Classification:

C12Q 168
C12M 140

US Classification:

435 6

Abstract:

The detectability of luminescent molecules in solution is enhanced by reducing the background luminescence due to impurity species also present in the solution. A light source that illuminates the solution acts to photolyze the impurities so that the impurities do not luminesce in the fluorescence band of the molecule of interest. Molecules of interest may be carried through the photolysis region in the solution or may be introduced into the solution after the photolysis region.

US Patent:

58276637, Oct 27, 1998

Filed:

Oct 4, 1996

Appl. No.:

8/727841

Inventors:

Rhett L. Affleck - Los Alamos NM
W. Patrick Ambrose - Los Alamos NM
James N. Demas - Charlottesville VA
Peter M. Goodwin - Jemez Springs NM
Mitchell E. Johnson - Pittsburgh PA
Richard A. Keller - Los Alamos NM
Jeffrey T. Petty - Los Alamos NM
Jay A. Schecker - Santa Fe NM
Ming Wu - Los Alamos NM

Assignee:

The Regents of the University of California - Los Alamos NM

International Classification:

C12Q 168
C12Q 137
C12N 1500

US Classification:

435 6

Abstract:

The detectability of luminescent molecules in solution is enhanced by reducing the background luminescence due to impurity species also present in the solution. A light source that illuminates the solution acts to photolyze the impurities so that the impurities do not luminesce in the fluorescence band of the molecule of interest. Molecules of interest may be carried through the photolysis region in the solution or may be introduced into the solution after the photolysis region.

US Patent:

57996822, Sep 1, 1998

Filed:

Dec 6, 1996

Appl. No.:

8/758738

Inventors:

Rhett L. Affleck - Lawrenceville NJ
James N. Demas - Charlottesville VA
Peter M. Goodwin - Jemez Springs NM
Richard Keller - Los Alamos NM
Ming Wu - Middle Island NY

Assignee:

The Regents of the University of California - Los Alamos NM

International Classification:

F15C 120

US Classification:

137 14

Abstract:

An analyte fluid stream with first molecules having relatively low molecular weight and a corresponding high coefficient of diffusion has reduced diffusional defocusing out of an analyte fluid stream. The analyte fluid stream of first molecules is associated with second molecules of relatively high molecular weight having a relatively low coefficient of diffusion and a binding constant effective to associate with the first molecules. A focused analyte fluid stream is maintained since the combined molecular weight of the associated first and second molecules is effective to minimize diffusion of the first molecules out of the analyte fluid stream.

US Patent:

48453684, Jul 4, 1989

Filed:

Jun 26, 1987

Appl. No.:

7/068005

Inventors:

James N. Demas - Charlottesville VA
Wesley M. Jones - Los Alamos NM
Richard A. Keller - Los Alamos NM

Assignee:

The United States of America as represented by the United States
Department of Energy - Washington DC

International Classification:

G01T 1204

US Classification:

2504591

Abstract:

Method for reducing quenching effects in analytical luminescence measurements. Two embodiments of the present invention are described which relate to a form of time resolution based on the amplitudes and phase shifts of modulated emission signals. In the first embodiment, the measured modulated emission signal is substantially independent of sample quenching at sufficiently high frequenices. In the second embodiment, the modulated amplitude and the phase shift between the emission signal and the excitation source are simultaneously measured. Using either method, the observed modulated amplitude may reduced to tis unquenched value.

US Patent:

20180355242, Dec 13, 2018

Filed:

Dec 12, 2016

Appl. No.:

16/060761

Inventors:

- Charlottesville VA, US
James N. DEMAS - Charlottesville VA, US
Alexander MATTHEW - Charlottesville VA, US
Christopher DEROSA - Charlottesville VA, US
Scott SEAMAN - Charlottesville VA, US

International Classification:

C09K 11/06
G01N 33/58

Abstract:

Disclosed herein are methods and related imaging systems to measure oxygenation levels on a surface. Methods of monitoring wound healing with dual emissive difluoroboron naphthyl-phenyl β-diketonate polylactide materials are disclosed.