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035 a| (OCoLC)1449649582;

090 a| QP101;

049 a| EREE;

100 1 a| Jones, Zachary D.,e| author;

245 10 a| Spectrophotometric study of turbid samples and artery phantoms for modeling of photoplethysmography process /c| by Zachary D. Jones.;

264 1 a| [Greenville, N.C.] :b| [East Carolina University],c| 2024.;

300 a| 1 online resource (181 pages) :b| illustrations (some color);

336 a| textb| txt2| rdacontent;

337 a| computerb| c2| rdamedia;

338 a| online resourceb| cr2| rdacarrier;

347 a| text fileb| application/pdfc| 9.89 MB2| rda;

538 a| System requirements: Adobe Reader.;

538 a| Mode of access: World Wide Web.;

502 b| Ph.D.c| East Carolina Universityd| 2024.;

500 a| Presented to the Faculty of the Department of Physics;

500 a| Advisor: Xin-Hua Hu;

500 a| Title from PDF t.p. (viewed May 21, 2025).;

520 3 a| Photoplethysmography (PPG) has long been explored and applied as a useful modality to measure numerous physiologically relevant parameters within cardiologic and home-health applications. Despite these successes, the fundamental process of light-tissue interaction underlying PPG signals remains poorly understood. This dissertation research develops the tools needed for experimental and numerical investigations of the underlying light-matter interaction of PPG signals within the framework of radiative transfer theory (RT) to improve the understanding of physiological factors attributing to their formation. We have developed and validated a multiparameter spectrophotometry (MPS) system and a novel collection of algorithms for recovery of bulk optical parameters of turbid media samples from measured signals of diffuse reflectance, diffuse transmittance, and forward transmittance from 460 to 1000 nm without integrating spheres. A particle swarm optimization (PSO) based inverse solver has been combined with GPU-executed Monte Carlo (MC) simulations to rapidly retrieve optical parameters defined by the RT theory. Extensive validation results of our MPS system are presented that include determination of RT parameters of Intralipid and bovine milk samples as functions of wavelength. Additionally, we demonstrate the ability of our novel MPS approach to measure a competitive threshold concentration of detectable bacteria in milk. The MPS system and the inverse solver were then applied in a PPG modeling study. Multiple polydimethylsiloxane (PDMS)-human blood phantoms were constructed to simulate up to eight blood vessels embedded in a tissue phantom. Scattered light was measured as PPG signals under various values of blood pressure at multiple wavelengths and quantitatively compared to those obtained by MC simulations. Our results demonstrate the potential of our phantom model to advance the understanding of factors that give rise to the photoplethysmogram. Future improvements of our phantom study may provide additional insight on extraction of useful biomarkers from PPG measurement to monitor cardiovascular health in clinics.;

504 a| Includes bibliographical references.;

650 0 a| Plethysmography.;

650 0 a| Spectrophotometry.;

650 0 a| Cardiovascular systemx| Diseases.;

650 7 a| spectrophotometry.2| aat0| (CStmoGRI)aat300223828;

653 a| Photoplethysmography;

653 a| bulk optical parameters;

653 a| turbid media;

700 1 a| Hu, Xin-Hua,e| degree supervisor.;

710 2 a| East Carolina University.b| Department of Physics.;

856 40 z| Access via ScholarShipu| http://hdl.handle.net/10342/13394;

994 a| C0b| ERE;

596 a| 1 4;

998 a| 6462634;

999 a| CLICK ON WEB ADDRESSw| ASISc| 1i| 6462634-1001l| JNETm| JOYNERr| Ys| Yt| JNE3ETDu| 7/24/2024x| ETDz| JERESOURCE;

999 a| CLICK ON WEB ADDRESSw| ASISc| 1i| 6462634-2001l| HSLELECm| HSLr| Ys| Yt| HEETDu| 7/24/2024x| ETDz| HERESOURCE;

Spectrophotometric study of turbid samples and artery phantoms for modeling of photoplethysmography process / by Zachary D. Jones.

Author/creator	Jones, Zachary D. author
Other author	Hu, Xin-Hua, degree supervisor.
Other author	East Carolina University. Department of Physics.
Format	Theses and dissertations
Publication	[Greenville, N.C.] : [East Carolina University], 2024.
Description	1 online resource (181 pages) : illustrations (some color)
Supplemental Content	Access via ScholarShip
Subjects	Plethysmography. Spectrophotometry. Cardiovascular system--Diseases.

Summary	Photoplethysmography (PPG) has long been explored and applied as a useful modality to measure numerous physiologically relevant parameters within cardiologic and home-health applications. Despite these successes, the fundamental process of light-tissue interaction underlying PPG signals remains poorly understood. This dissertation research develops the tools needed for experimental and numerical investigations of the underlying light-matter interaction of PPG signals within the framework of radiative transfer theory (RT) to improve the understanding of physiological factors attributing to their formation. We have developed and validated a multiparameter spectrophotometry (MPS) system and a novel collection of algorithms for recovery of bulk optical parameters of turbid media samples from measured signals of diffuse reflectance, diffuse transmittance, and forward transmittance from 460 to 1000 nm without integrating spheres. A particle swarm optimization (PSO) based inverse solver has been combined with GPU-executed Monte Carlo (MC) simulations to rapidly retrieve optical parameters defined by the RT theory. Extensive validation results of our MPS system are presented that include determination of RT parameters of Intralipid and bovine milk samples as functions of wavelength. Additionally, we demonstrate the ability of our novel MPS approach to measure a competitive threshold concentration of detectable bacteria in milk. The MPS system and the inverse solver were then applied in a PPG modeling study. Multiple polydimethylsiloxane (PDMS)-human blood phantoms were constructed to simulate up to eight blood vessels embedded in a tissue phantom. Scattered light was measured as PPG signals under various values of blood pressure at multiple wavelengths and quantitatively compared to those obtained by MC simulations. Our results demonstrate the potential of our phantom model to advance the understanding of factors that give rise to the photoplethysmogram. Future improvements of our phantom study may provide additional insight on extraction of useful biomarkers from PPG measurement to monitor cardiovascular health in clinics.
General note	Presented to the Faculty of the Department of Physics
General note	Advisor: Xin-Hua Hu
General note	Title from PDF t.p. (viewed May 21, 2025).
Dissertation note	Ph.D. East Carolina University 2024.
Bibliography note	Includes bibliographical references.
Technical details	System requirements: Adobe Reader.
Technical details	Mode of access: World Wide Web.

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Spectrophotometric study of turbid samples and artery phantoms for modeling of photoplethysmography process / by Zachary D. Jones.

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