Joseph Chaiken | Syracuse University (original) (raw)
Papers by Joseph Chaiken
Optical Biopsy XVI: Toward Real-Time Spectroscopic Imaging and Diagnosis, 2018
We report a small study to test a methodology for real-time probing of chemical and physical chan... more We report a small study to test a methodology for real-time probing of chemical and physical changes in spinal cords in the immediate aftermath of a localized contusive injury. Raman spectroscopy, optical profilimetry and scanning NIR autofluorescence images were obtained simultaneously in vivo, within a 3 x 7 mm field, on spinal cords that had been surgically exposed between T9 and T10. The collected data was used alone and/or combined in a unique algorithm. A total of six rats were studied in two N=3 groups i.e. Injured and Control. A single 830 nm laser (100 μm round spot) was either 1) spatially scanned across the cord or 2) held at a specified location relative to the injury for a longer period of time to improve signal to noise in the Raman spectra. Line scans reveal photobleaching effects and surface profiles possibly allowing identification of the anterior median longitudinal artery. Analysis of the Raman spectra suggest that the tissues were equally hypoxic for both the control and injured animals i.e. a possible artifact of anesthesia and surgery. On the other hand, only injured cords display Raman features possibly indicating that extensive, localized protein phosphorylation occurs in minutes following spinal cord trauma.
Advanced Biomedical and Clinical Diagnostic and Surgical Guidance Systems XVI, 2018
We previously reported a new algorithm “PV[O]H” for continuous, noninvasive, in vivo monitoring o... more We previously reported a new algorithm “PV[O]H” for continuous, noninvasive, in vivo monitoring of hematocrit changes in blood and have since shown its utility for monitoring in humans during 1) hemodialysis, 2) orthostatic perturbations and 3) during blood loss and fluid replacement in a rat model. We now show that the algorithm is sensitive to changes in hemoglobin oxygen saturation. We document the phenomenology of the effect and explain the effect using new results obtained from humans and rat models. The oxygen sensitivity derives from the differential absorption of autofluorescence originating in the static tissues by oxy and deoxy hemoglobin. Using this approach we show how to perform simultaneous, noninvasive, in vivo, continuous monitoring of hematocrit, vascular volume, hemoglobin oxygen saturation, pulse rate and breathing rate in mammals using a single light source. We suspect that monitoring of changes in this suite of vital signs can be provided with improved time response, sensitivity and precision compared to existing methodologies. Initial results also offer a more detailed glimpse into the systemic oxygen transport in the circulatory system of humans.
The Journal of Physical Chemistry A, 2015
The Smoluchowski equations provide a rigorous and efficient means for including multiple kinetic ... more The Smoluchowski equations provide a rigorous and efficient means for including multiple kinetic pathways when modeling coalescence growth systems. Originally written for a constant temperature and volume system, the equations must be modified if temperature and pressure vary during the coalescence time. In this paper, the equations are generalized, and adaptations appropriate to the situation presented by supersonic nozzle beam expansions are described. Given rate constants for all the cluster−cluster reactions, solution of the Smoluchowski equations would yield the abundances of clusters of all sizes at all times. This is unlikely, but we show that if these rate constants scale with the sizes of the reacting partners, the asymptotic (large size and large time) form of the cluster size distribution can be predicted. Experimentally determined distributions for He fit the predicted asymptotic distribution very well. Deviations between predicted and observed distributions allow identification of special cluster sizes that is, magic numbers. Furthermore, fitting an observed distribution to the theoretical form yields the base agglomeration cross section, from which all cluster−cluster rate constants may be obtained by scaling. Comparing the base cross section to measures of size and reactivity gives information about the coalescence process.
Journal of Applied Physics, 1991
Intracavity laser absorption spectroscopy was used to measure the number density of neutral groun... more Intracavity laser absorption spectroscopy was used to measure the number density of neutral ground state barium atoms desorbed from an operating dispenser cathode. The measurement suggests an order of magnitude value of 108 atoms/cm3 at a distance of 5 cm from the emitting surface. This is the first direct state selective measurement of the barium density near to the surface of an operating cathode which can be directly traced to conventional multipass absorption spectroscopy. The value we obtain is consistent with results reported by other workers using less direct methods and allows more detailed statements to be made concerning the chemical state of the Ba at the instant of desorption.
Chemical Physics Letters, 1979
... J. Chaiken, Thomas Benson, M. Gurnick and JD McDonald. ... References. Volume 61, number 1 CH... more ... J. Chaiken, Thomas Benson, M. Gurnick and JD McDonald. ... References. Volume 61, number 1 CHEMICAL PHYSICS LETTERS 1 February 1979 QUANTUM BEATS IN SINGLE ROVIBRONIC STATE FLUORESCENCE OF BIACETYL J. CHAIKEN, Thomas BENSON. ...
1999 IEEE Aerospace Conference. Proceedings (Cat. No.99TH8403), 1999
We have constructed and tested a spin stand based demonstration system for a new form of optical ... more We have constructed and tested a spin stand based demonstration system for a new form of optical memory. Based on a new two color storage process which utilizes a form of tungsten oxide as the physical medium, this system offers potential advantages in storage density, write speed, signal to noise, processing flexibility, data robustness, and overall cost. In this paper we describe the system and its performance on prototype disks. Issues regarding choices of wavelengths, write power and speed will be discussed.
The Journal of Chemical Physics, 1982
ABSTRACT Laser induced fluorescence excitation spectra of supersonic nozzle beam cooled methylgly... more ABSTRACT Laser induced fluorescence excitation spectra of supersonic nozzle beam cooled methylglyoxal‐d4 reveal that a deformation occurs during the radiative electronic transition that destroys the planarity of the carbonyls. Consistent with the expectation that deuteration results in an increased number of low frequency vibrations, the number of observed vibronic lines increased and the energy of the breakoff of sharp vibronic structure above the O–O band decreased compared to the protonated molecule. As for the protonated molecule, the observed vibronic structure can be almost completely assigned on the basis of two fundamentals and a repeating pattern of lines that involves the methyl internal rotation and the cis–trans internal rotation of the carbonyls. Systematic anharmonicities involving the pattern and only one of the two fundamentals suggests which molecular motions correspond to the observed fundamentals. Quantum beat and Zeeman effect experiments unambiguously show the triplet states that are responsible for the radiationless dynamics that are known to occur in these molecules. All quantum beat data were analyzable using our previously published perturbation theory method and yield triplet densities which are intermediate compared to methylglyoxal‐h4 and biacetyl‐h6 and in good agreement with an estimate obtained by direct state coupling. The density of effectively coupled triplet states increases with the energy of the initially prepared singlet state and the intramolecular coupling is 2–15 MHz independent of the amount of vibrational‐rotational excitation present. Radiationless transitions in these highly excited molecules are evidently not subject to any overriding selection rules other than spatial symmetry and conservation of total energy, total angular momentum, and nuclear spin. Zeeman experiments indicate extensive coupling of all molecular angular momenta which initially decouple at only ∼10 G. In this low field regime complicated splittings are observed which correspond roughly to g values of about 67% that of a free electron. At larger fields of about 50–60 G, the microsecond fluorescence is nearly completely quenched, and although we cannot completely explain this effect at present, we suspect both intra‐ and intermolecular processes are possible.
Proceedings SPIE, 2020
We recently reported the first noninvasive, label free measurement of pH in a bodily fluid in viv... more We recently reported the first noninvasive, label free measurement of pH in a bodily fluid in vivo using only Raman spectra i.e. in vivo rat model measurements probing the immediate vicinity of a contusive spinal cord injury (SCI) in the first minutes and hours after injury. Calibrated and assigned using Raman spectra of authentic materials, in the rat model we were not able to sample the cerebrospinal fluid (CSF) to allow comparison with an independent measurement of the pH. Swine presents a better model because they allow physical sampling of CSF, although still not ideal for our purposes. We were only able to physically sample CSF from the fourth cerebral ventricle of 2 different animals, before and after all spectral measurements on cords were completed. One measurement each for 2 different animals on physically sampled CSF averaged a pH of 7.001±0.106 (N=2) as per standard laboratory instrumentation. Using a dynamic analysis and the Henderson-Hasselbalch equation, the average o...
ACS Symposium Series, 1993
Laser Applications to Chemical Dynamics, 1987
ABSTRACT We have measured one color multiphoton dissociation/ionization (MPD/MPI) spectra for a s... more ABSTRACT We have measured one color multiphoton dissociation/ionization (MPD/MPI) spectra for a series of arene molybdenum tricarbonyls. These experiments measure the relative timescales of multiphoton excitation, intramolecular energy redistribution (IER) and unimolecular dissociation under collision free conditions. The results indicate that IER is accelerated by the presence of low frequency vibrations and by molecular structures and bonding which enable a molecule to remain intact longer during the course of multiphoton excitation. The results for the organomolybdenum molecules are consistent with our earlier results obtained in a similar study of organochromium molecules.
NTIS it will be releasable to the general public, including foreign nations. RL-TR-94-189 has bee... more NTIS it will be releasable to the general public, including foreign nations. RL-TR-94-189 has been reviewed and is approved for publication.
L'invention concerne un dispositif de modulation tissulaire (100) qui s'utilise pour real... more L'invention concerne un dispositif de modulation tissulaire (100) qui s'utilise pour realiser une spectroscopie tissulaire chez un sujet. Dans une forme de realisation, le dispositif comprend une gaine interieure (220), une gaine exterieure (210) et une ouverture (140) menagee a travers les gaines interieure (220) et exterieure (210), lesquelles sont constituees d'un materiau suffisamment souple pour permettre de fixer le dispositif sur une partie d'un tissu a sonder par spectroscopie. Les gaines interieure (220) et exterieure (210) sont aboutees de sorte qu'au moins un element de regulation de la temperature (110) puisse etre dispose entre elles. L'ouverture (140) est suffisamment transparente pour qu'un rayonnement electromagnetique puisse etre achemine vers ou recueilli d'un tissu sous-jacent a travers les gaines interieure (220) et exterieure (210). L'invention concerne en outre un procede pour moduler chez un sujet la temperature d'un tis...
Biophotonics: Photonic Solutions for Better Health Care V, 2016
A new device incorporating a new algorithm and measurement process allows simultaneous noninvasiv... more A new device incorporating a new algorithm and measurement process allows simultaneous noninvasive in vivo monitoring of intravascular plasma volume and red blood cell volume. The purely optical technique involves probing fingertip skin with near infrared laser light and collecting the wavelength shifted light, that is, the inelastic emission (IE) which includes the unresolved Raman and fluorescence, and the un-shifted emission, that is, the elastic emission (EE) which includes both the Rayleigh and Mie scattered light. Our excitation and detection geometry is designed so that from these two simultaneous measurements we can calculate two parameters within the single scattering regime using radiation transfer theory, the intravascular plasma volume fraction and the red blood cell volume fraction. Previously calibrated against a gold standard FDA approved device, 2 hour monitoring sessions on three separate occasions over a three week span for a specific, motionless, and mostly sleeping individual produced 3 records containing a total of 5706 paired measurements of hematocrit and plasma volume. The average over the three runs, relative to the initial plasma volume taken as 100%, of the plasma volume±1σ was 97.56±0.55 or 0.56%.For the same three runs, the average relative hematocrit (Hct), referenced to an assumed initial value of 28.35 was 29.37±0.12 or stable to ±0.4%.We observe local deterministic circulation effects apparently associated with the pressure applied by the finger probe as well as longer timescale behavior due to normal ebb and flow of internal fluids due to posture changes and tilt table induced gravity gradients.
Advanced Biomedical and Clinical Diagnostic and Surgical Guidance Systems XVII
Thermoregulation is a mammalian physiological function fulfilled in large part by autonomic contr... more Thermoregulation is a mammalian physiological function fulfilled in large part by autonomic control of blood flow. We demonstrate the variation in hematocrit (Hct) and intravascular volume (VV) in the peripheral circulation when the external means of maintaining the initial thermal disequilibrium is removed using a PV[O]H device capable of noninvasively measuring both Hct and VV with unprecedented sensitivity, accuracy and precision on a 3 second timescale. Calibrated using an FDA approved device now in standard use for monitoring Hct during dialysis, the PV[O]H detection limit for measuring Hct variation is ±0.03 where 45% is normal. Observing the return to thermal equilibrium at 2 separate anatomic locations, we observe the return to normal homeostasis in a matter of a few minutes. Heat induced vasodilation results in an antecedent increase in plasma volume in greater proportion than for red blood cells into the dilated capillaries. At equilibrium homeostasis i.e. when there is no externally maintained thermal gradient we observe periodic fluctuations in the peripheral Hct and VV on a roughly 15 second to 1.5 minute timescale.
Supplemental material, ASP872754 Supplemental Material for Coupled Turbidity and Spectroscopy Pro... more Supplemental material, ASP872754 Supplemental Material for Coupled Turbidity and Spectroscopy Problems: A Simple Algorithm for Volumetric Analysis of Optically Thin or Dilute, In Vitro Bacterial Cultures in Various Media by Steven Ortiz, Richard T. McDonough, Paul Dent, Jerry Goodisman and Joseph Chaiken in Applied Spectroscopy
Biophotonics Congress: Biomedical Optics 2020 (Translational, Microscopy, OCT, OTS, BRAIN)
Biomedical applications of Raman spectroscopy must separate fluorescence/phosphorescence from the... more Biomedical applications of Raman spectroscopy must separate fluorescence/phosphorescence from the Raman emission. Two “baseline correction” approaches appear in the literature with success. A recent study [1] suggests that one may be advantageous over the other.
Biophotonics Congress: Optics in the Life Sciences Congress 2019 (BODA,BRAIN,NTM,OMA,OMP)
PV[O]H involves simultaneously measuring elastic scattering and inelastic emission as a near infr... more PV[O]H involves simultaneously measuring elastic scattering and inelastic emission as a near infrared laser is scanned across tissue. Contrast for imaging derives from correlated variations in local turbidity and Raman/fluorescence emission.
The initial biological response to spinal cord injury is initiated by intra- and extracellular ch... more The initial biological response to spinal cord injury is initiated by intra- and extracellular chemical signals. We compare Raman spectra of injured spinal cord obtained minutes after injury to those of uninjured spinal cord to obtain chemical information that precedes the biological response. We studied 29 rats including both Injured and Control using Raman spectra of spinal cords in vivo. Principal Component Analysis (PCA) indicates that <99% of the variation of these spectra across both Injured and Control groups is accounted for with 3 components. The first component does not vary significantly representing structural materials. The second and third components reflect the variation in the chemistry of the cerebrospinal fluid. We demonstrate the first noninvasive in vivo measurement of pH in the CSF using only Raman spectra. We hypothesize that the earliest inflammatory response to mild contusive injury reflects the chemistry of inorganic phosphate present at abnormally high c...
Optical Biopsy XVI: Toward Real-Time Spectroscopic Imaging and Diagnosis, 2018
We report a small study to test a methodology for real-time probing of chemical and physical chan... more We report a small study to test a methodology for real-time probing of chemical and physical changes in spinal cords in the immediate aftermath of a localized contusive injury. Raman spectroscopy, optical profilimetry and scanning NIR autofluorescence images were obtained simultaneously in vivo, within a 3 x 7 mm field, on spinal cords that had been surgically exposed between T9 and T10. The collected data was used alone and/or combined in a unique algorithm. A total of six rats were studied in two N=3 groups i.e. Injured and Control. A single 830 nm laser (100 μm round spot) was either 1) spatially scanned across the cord or 2) held at a specified location relative to the injury for a longer period of time to improve signal to noise in the Raman spectra. Line scans reveal photobleaching effects and surface profiles possibly allowing identification of the anterior median longitudinal artery. Analysis of the Raman spectra suggest that the tissues were equally hypoxic for both the control and injured animals i.e. a possible artifact of anesthesia and surgery. On the other hand, only injured cords display Raman features possibly indicating that extensive, localized protein phosphorylation occurs in minutes following spinal cord trauma.
Advanced Biomedical and Clinical Diagnostic and Surgical Guidance Systems XVI, 2018
We previously reported a new algorithm “PV[O]H” for continuous, noninvasive, in vivo monitoring o... more We previously reported a new algorithm “PV[O]H” for continuous, noninvasive, in vivo monitoring of hematocrit changes in blood and have since shown its utility for monitoring in humans during 1) hemodialysis, 2) orthostatic perturbations and 3) during blood loss and fluid replacement in a rat model. We now show that the algorithm is sensitive to changes in hemoglobin oxygen saturation. We document the phenomenology of the effect and explain the effect using new results obtained from humans and rat models. The oxygen sensitivity derives from the differential absorption of autofluorescence originating in the static tissues by oxy and deoxy hemoglobin. Using this approach we show how to perform simultaneous, noninvasive, in vivo, continuous monitoring of hematocrit, vascular volume, hemoglobin oxygen saturation, pulse rate and breathing rate in mammals using a single light source. We suspect that monitoring of changes in this suite of vital signs can be provided with improved time response, sensitivity and precision compared to existing methodologies. Initial results also offer a more detailed glimpse into the systemic oxygen transport in the circulatory system of humans.
The Journal of Physical Chemistry A, 2015
The Smoluchowski equations provide a rigorous and efficient means for including multiple kinetic ... more The Smoluchowski equations provide a rigorous and efficient means for including multiple kinetic pathways when modeling coalescence growth systems. Originally written for a constant temperature and volume system, the equations must be modified if temperature and pressure vary during the coalescence time. In this paper, the equations are generalized, and adaptations appropriate to the situation presented by supersonic nozzle beam expansions are described. Given rate constants for all the cluster−cluster reactions, solution of the Smoluchowski equations would yield the abundances of clusters of all sizes at all times. This is unlikely, but we show that if these rate constants scale with the sizes of the reacting partners, the asymptotic (large size and large time) form of the cluster size distribution can be predicted. Experimentally determined distributions for He fit the predicted asymptotic distribution very well. Deviations between predicted and observed distributions allow identification of special cluster sizes that is, magic numbers. Furthermore, fitting an observed distribution to the theoretical form yields the base agglomeration cross section, from which all cluster−cluster rate constants may be obtained by scaling. Comparing the base cross section to measures of size and reactivity gives information about the coalescence process.
Journal of Applied Physics, 1991
Intracavity laser absorption spectroscopy was used to measure the number density of neutral groun... more Intracavity laser absorption spectroscopy was used to measure the number density of neutral ground state barium atoms desorbed from an operating dispenser cathode. The measurement suggests an order of magnitude value of 108 atoms/cm3 at a distance of 5 cm from the emitting surface. This is the first direct state selective measurement of the barium density near to the surface of an operating cathode which can be directly traced to conventional multipass absorption spectroscopy. The value we obtain is consistent with results reported by other workers using less direct methods and allows more detailed statements to be made concerning the chemical state of the Ba at the instant of desorption.
Chemical Physics Letters, 1979
... J. Chaiken, Thomas Benson, M. Gurnick and JD McDonald. ... References. Volume 61, number 1 CH... more ... J. Chaiken, Thomas Benson, M. Gurnick and JD McDonald. ... References. Volume 61, number 1 CHEMICAL PHYSICS LETTERS 1 February 1979 QUANTUM BEATS IN SINGLE ROVIBRONIC STATE FLUORESCENCE OF BIACETYL J. CHAIKEN, Thomas BENSON. ...
1999 IEEE Aerospace Conference. Proceedings (Cat. No.99TH8403), 1999
We have constructed and tested a spin stand based demonstration system for a new form of optical ... more We have constructed and tested a spin stand based demonstration system for a new form of optical memory. Based on a new two color storage process which utilizes a form of tungsten oxide as the physical medium, this system offers potential advantages in storage density, write speed, signal to noise, processing flexibility, data robustness, and overall cost. In this paper we describe the system and its performance on prototype disks. Issues regarding choices of wavelengths, write power and speed will be discussed.
The Journal of Chemical Physics, 1982
ABSTRACT Laser induced fluorescence excitation spectra of supersonic nozzle beam cooled methylgly... more ABSTRACT Laser induced fluorescence excitation spectra of supersonic nozzle beam cooled methylglyoxal‐d4 reveal that a deformation occurs during the radiative electronic transition that destroys the planarity of the carbonyls. Consistent with the expectation that deuteration results in an increased number of low frequency vibrations, the number of observed vibronic lines increased and the energy of the breakoff of sharp vibronic structure above the O–O band decreased compared to the protonated molecule. As for the protonated molecule, the observed vibronic structure can be almost completely assigned on the basis of two fundamentals and a repeating pattern of lines that involves the methyl internal rotation and the cis–trans internal rotation of the carbonyls. Systematic anharmonicities involving the pattern and only one of the two fundamentals suggests which molecular motions correspond to the observed fundamentals. Quantum beat and Zeeman effect experiments unambiguously show the triplet states that are responsible for the radiationless dynamics that are known to occur in these molecules. All quantum beat data were analyzable using our previously published perturbation theory method and yield triplet densities which are intermediate compared to methylglyoxal‐h4 and biacetyl‐h6 and in good agreement with an estimate obtained by direct state coupling. The density of effectively coupled triplet states increases with the energy of the initially prepared singlet state and the intramolecular coupling is 2–15 MHz independent of the amount of vibrational‐rotational excitation present. Radiationless transitions in these highly excited molecules are evidently not subject to any overriding selection rules other than spatial symmetry and conservation of total energy, total angular momentum, and nuclear spin. Zeeman experiments indicate extensive coupling of all molecular angular momenta which initially decouple at only ∼10 G. In this low field regime complicated splittings are observed which correspond roughly to g values of about 67% that of a free electron. At larger fields of about 50–60 G, the microsecond fluorescence is nearly completely quenched, and although we cannot completely explain this effect at present, we suspect both intra‐ and intermolecular processes are possible.
Proceedings SPIE, 2020
We recently reported the first noninvasive, label free measurement of pH in a bodily fluid in viv... more We recently reported the first noninvasive, label free measurement of pH in a bodily fluid in vivo using only Raman spectra i.e. in vivo rat model measurements probing the immediate vicinity of a contusive spinal cord injury (SCI) in the first minutes and hours after injury. Calibrated and assigned using Raman spectra of authentic materials, in the rat model we were not able to sample the cerebrospinal fluid (CSF) to allow comparison with an independent measurement of the pH. Swine presents a better model because they allow physical sampling of CSF, although still not ideal for our purposes. We were only able to physically sample CSF from the fourth cerebral ventricle of 2 different animals, before and after all spectral measurements on cords were completed. One measurement each for 2 different animals on physically sampled CSF averaged a pH of 7.001±0.106 (N=2) as per standard laboratory instrumentation. Using a dynamic analysis and the Henderson-Hasselbalch equation, the average o...
ACS Symposium Series, 1993
Laser Applications to Chemical Dynamics, 1987
ABSTRACT We have measured one color multiphoton dissociation/ionization (MPD/MPI) spectra for a s... more ABSTRACT We have measured one color multiphoton dissociation/ionization (MPD/MPI) spectra for a series of arene molybdenum tricarbonyls. These experiments measure the relative timescales of multiphoton excitation, intramolecular energy redistribution (IER) and unimolecular dissociation under collision free conditions. The results indicate that IER is accelerated by the presence of low frequency vibrations and by molecular structures and bonding which enable a molecule to remain intact longer during the course of multiphoton excitation. The results for the organomolybdenum molecules are consistent with our earlier results obtained in a similar study of organochromium molecules.
NTIS it will be releasable to the general public, including foreign nations. RL-TR-94-189 has bee... more NTIS it will be releasable to the general public, including foreign nations. RL-TR-94-189 has been reviewed and is approved for publication.
L'invention concerne un dispositif de modulation tissulaire (100) qui s'utilise pour real... more L'invention concerne un dispositif de modulation tissulaire (100) qui s'utilise pour realiser une spectroscopie tissulaire chez un sujet. Dans une forme de realisation, le dispositif comprend une gaine interieure (220), une gaine exterieure (210) et une ouverture (140) menagee a travers les gaines interieure (220) et exterieure (210), lesquelles sont constituees d'un materiau suffisamment souple pour permettre de fixer le dispositif sur une partie d'un tissu a sonder par spectroscopie. Les gaines interieure (220) et exterieure (210) sont aboutees de sorte qu'au moins un element de regulation de la temperature (110) puisse etre dispose entre elles. L'ouverture (140) est suffisamment transparente pour qu'un rayonnement electromagnetique puisse etre achemine vers ou recueilli d'un tissu sous-jacent a travers les gaines interieure (220) et exterieure (210). L'invention concerne en outre un procede pour moduler chez un sujet la temperature d'un tis...
Biophotonics: Photonic Solutions for Better Health Care V, 2016
A new device incorporating a new algorithm and measurement process allows simultaneous noninvasiv... more A new device incorporating a new algorithm and measurement process allows simultaneous noninvasive in vivo monitoring of intravascular plasma volume and red blood cell volume. The purely optical technique involves probing fingertip skin with near infrared laser light and collecting the wavelength shifted light, that is, the inelastic emission (IE) which includes the unresolved Raman and fluorescence, and the un-shifted emission, that is, the elastic emission (EE) which includes both the Rayleigh and Mie scattered light. Our excitation and detection geometry is designed so that from these two simultaneous measurements we can calculate two parameters within the single scattering regime using radiation transfer theory, the intravascular plasma volume fraction and the red blood cell volume fraction. Previously calibrated against a gold standard FDA approved device, 2 hour monitoring sessions on three separate occasions over a three week span for a specific, motionless, and mostly sleeping individual produced 3 records containing a total of 5706 paired measurements of hematocrit and plasma volume. The average over the three runs, relative to the initial plasma volume taken as 100%, of the plasma volume±1σ was 97.56±0.55 or 0.56%.For the same three runs, the average relative hematocrit (Hct), referenced to an assumed initial value of 28.35 was 29.37±0.12 or stable to ±0.4%.We observe local deterministic circulation effects apparently associated with the pressure applied by the finger probe as well as longer timescale behavior due to normal ebb and flow of internal fluids due to posture changes and tilt table induced gravity gradients.
Advanced Biomedical and Clinical Diagnostic and Surgical Guidance Systems XVII
Thermoregulation is a mammalian physiological function fulfilled in large part by autonomic contr... more Thermoregulation is a mammalian physiological function fulfilled in large part by autonomic control of blood flow. We demonstrate the variation in hematocrit (Hct) and intravascular volume (VV) in the peripheral circulation when the external means of maintaining the initial thermal disequilibrium is removed using a PV[O]H device capable of noninvasively measuring both Hct and VV with unprecedented sensitivity, accuracy and precision on a 3 second timescale. Calibrated using an FDA approved device now in standard use for monitoring Hct during dialysis, the PV[O]H detection limit for measuring Hct variation is ±0.03 where 45% is normal. Observing the return to thermal equilibrium at 2 separate anatomic locations, we observe the return to normal homeostasis in a matter of a few minutes. Heat induced vasodilation results in an antecedent increase in plasma volume in greater proportion than for red blood cells into the dilated capillaries. At equilibrium homeostasis i.e. when there is no externally maintained thermal gradient we observe periodic fluctuations in the peripheral Hct and VV on a roughly 15 second to 1.5 minute timescale.
Supplemental material, ASP872754 Supplemental Material for Coupled Turbidity and Spectroscopy Pro... more Supplemental material, ASP872754 Supplemental Material for Coupled Turbidity and Spectroscopy Problems: A Simple Algorithm for Volumetric Analysis of Optically Thin or Dilute, In Vitro Bacterial Cultures in Various Media by Steven Ortiz, Richard T. McDonough, Paul Dent, Jerry Goodisman and Joseph Chaiken in Applied Spectroscopy
Biophotonics Congress: Biomedical Optics 2020 (Translational, Microscopy, OCT, OTS, BRAIN)
Biomedical applications of Raman spectroscopy must separate fluorescence/phosphorescence from the... more Biomedical applications of Raman spectroscopy must separate fluorescence/phosphorescence from the Raman emission. Two “baseline correction” approaches appear in the literature with success. A recent study [1] suggests that one may be advantageous over the other.
Biophotonics Congress: Optics in the Life Sciences Congress 2019 (BODA,BRAIN,NTM,OMA,OMP)
PV[O]H involves simultaneously measuring elastic scattering and inelastic emission as a near infr... more PV[O]H involves simultaneously measuring elastic scattering and inelastic emission as a near infrared laser is scanned across tissue. Contrast for imaging derives from correlated variations in local turbidity and Raman/fluorescence emission.
The initial biological response to spinal cord injury is initiated by intra- and extracellular ch... more The initial biological response to spinal cord injury is initiated by intra- and extracellular chemical signals. We compare Raman spectra of injured spinal cord obtained minutes after injury to those of uninjured spinal cord to obtain chemical information that precedes the biological response. We studied 29 rats including both Injured and Control using Raman spectra of spinal cords in vivo. Principal Component Analysis (PCA) indicates that <99% of the variation of these spectra across both Injured and Control groups is accounted for with 3 components. The first component does not vary significantly representing structural materials. The second and third components reflect the variation in the chemistry of the cerebrospinal fluid. We demonstrate the first noninvasive in vivo measurement of pH in the CSF using only Raman spectra. We hypothesize that the earliest inflammatory response to mild contusive injury reflects the chemistry of inorganic phosphate present at abnormally high c...