Robert A Peura

7003337, Feb 21, 2006

Apr 26, 2002

10/134310

Hannu Harjunmaa - Holden MA, US
Stevan Kun - Worcester MA, US
Robert A. Peura - Princeton MA, US
John A. Rolls - Armonk NY, US

VivaScan Corporation - West Boylston MA

A61B 5/00

600316, 600322, 600310

An improved method for non-invasively measuring a concentration of a target analyte dissolved in a fluid flowing through a sample is presented. It includes directing a probe beam of electromagnetic radiation, consisting of time multiplexed components of different wavelengths, through the sample and measuring the difference of the absorption of the radiation at at least one wavelength pair at different sample states. During sample state changes, the amount of fluid containing the target analyte within the sample is changing, which varies the total amount of target analyte in the sample, as well as the absorption properties of the sample. The sample states are produced, for instance, by compressing and uncompressing the tissue sample. The accuracy of the presented method is enhanced by including continuous estimation of the amount of the fluid containing the target analyte within the sample, and measurement of the variations of the absorption at a wavelength at which the target analyte absorbs significantly. The method is particularly useful in measuring the concentration of a target analyte, such as glucose, in tissue containing blood.

58072721, Sep 15, 1998

Oct 30, 1996

8/739162

Steven Kun - Worcester MA
Robert A. Peura - Princeton MA
Borislav Ristic - Worcester MA

Worcester Polytechnic Institute - Worcester MA

A61B 504

600547

An impedance spectroscopy tissue status monitoring and measurement system is disclosed. The system uses a synthesizer to generates electrical signals of selected frequencies. An electrical current source is responsive to the synthesizer and generates electrical currents for transmission through tissue. Electrodes or inductive coils of the system apply the electrical current to the tissue and sense voltages generated in the tissue in response to the electrical current. A controller determines the spectral response of the tissue by detecting magnitude and phase information of the electrical energy transmitted through the tissue. The information is then used to determine volumes of compartments within the tissue and ionic concentrations of compartmental fluids. Capacitive effects derived from the phase information are used to determine cell membrane functionality within the tissue. From this analysis, status, specifically, ischemia, may be determined on an absolute basis.

51370239, Aug 11, 1992

Apr 19, 1990

7/511229

Yitzhak Mendelson - Worcester MA
Robert A. Peura - Princeton MA
Hannu Harjunmaa - Vessy, CH

Worcester Polytechnic Institute - Worcester MA

A61B 500

128633

A non-invasive system for measuring the concentration of an analyte, such as glucose, in an absorbing matrix is described. The system directs beams of light at the matrix using an analyte sensitive wavelength and an analyte insensitive wavelength. The principles of photoplethysmography are applied to measure the change in light intensity caused by matrix absorption before and after the blood volume change caused by the systolic phase of the cardiac cycle. The change in light intensity is converted to an electrical signal which is used to adjust the light intensity and as a measure of analyte concentration.

51121247, May 12, 1992

Apr 19, 1990

7/511341

Hannu Harjunmaa - Vessy, CH
Robert A. Peura - Princeton MA
Yitzhak Mendelson - Worcester MA

Worcester Polytechnic Institute - Worcester MA

G01N 2159
G01N 3349

356 39

A non-invasive system for measuring the concentration of an analyte in an absorbing matrix is described. The system directs a beam of radiation at the matrix. The beam consists of a series of successive alternate pulses of electro-magnetic radiation, one of which is highly absorbed by the analyte and the other of which is non-absorbed. The transmitted or reflected beam is optically detected and an electrical signal proportional to beam intensity is used to adjust the beam intensity and as a measure of analyte concentration.

51580837, Oct 27, 1992

Oct 23, 1989

7/425490

Emilio Sacristan - Worcester MA
Albert Shahnarian - Princeton MA
Robert A. Peura - Princeton MA

Mountpelier Investments, S.A. - Vaduz

A61B 500

128635

The pCO. sub. 2 probe has a miniaturized glass bulb pH sensor concentrically arranged in a flexible, noncollapsible hollow tube. A silicone end cap is expanded in a freon solvent and placed over the end of the tube while the freon evaporates, returning the end cap to its normal contracted size where it forms a tight elastic fit. The pH sensor includes an internal electrode and an outer electrode is concentrically wrapped about the glass bulb so the electrodes are in close proximity. The glass bulb and the chamber defined by the tube walls and silicone membrane are both filled with suitable electrolytes of sufficient volume to minimize air bubbles. Without air bubbles, the electrodes remain emersed in the respective electrolytes regardless of the physical orientation of the probe.

57664323, Jun 16, 1998

Apr 17, 1996

8/632330

Raymond M. Dunn - Shrewsbury MA
Robert Harrington - Westboro MA
Robert Peura - Princeton MA
Stevan Kun - Worcester MA

University of Massachusetts - Boston MA
Worcester Polytechnic Institute - Worcester MA

G01N 2726

204412

A pH-measuring method and device for monitoring and then correcting for electrode drift is provided. The device includes a pH-measuring electrode and more than one reference electrode. During operation, the pH-measuring device is place in contact with a sample. The pH value measured at each electrode pair is due to the electrical potential difference between the pH electrode and the reference electrode. The maximum and minimum pH values are determined, and then the remaining pH values are averaged together to generate an overall average pH. The maximum and minimum pH values are subtracted from the average pH to generate a difference which is then compared to a user-defined drift level to determine if a particular electrode is deficient. The pH values from deficient electrodes are not considered when the overall pH of the sample is determined.