Next-Generation Raman tomography Instrument for Non-Invasive In Vivo Bone Imaging

Combining diffuse optical tomography methods with Raman spectroscopy of tissue provides the ability for in vivo measurements of chemical and molecular characteristics, which have the potential for being useful in diagnostic imaging. In this study a system for Raman tomography was developed and tested. A third generation microCT coupled system was developed to combine 10 detection fibers and 5 excitation fibers with laser line filtering and a Cytop reference signal. Phantom measurements of hydroxyapatite concentrations from 50 to 300 mg/ml had a linear response. Fiber placement and experiment design was optimized using cadaver animals with live animal measurements acquired to validate the systems capabilities. Promising results from the initial animal experiments presented here, pave the way for a study of longitudinal measurements during fracture healing and the scaling of the Raman tomography system towards human measurements

Raman Spectroscopy Detection of Molecular Changes Associated with Osteoarthritis.

Vibrational spectroscopic methods are minimally invasive, and are appropriate for use in clinical contexts. Methods were developed in this dissertation for evaluating joint damage and disease using Raman spectroscopy. Subtle changes in the molecular structure of joint tissue and synovial fluid precede morphological changes in the joint. The goal of this research is to develop Raman spectroscopic methods for the examination of joint tissue and biological fluids, for monitoring and detecting molecular alterations associated with osteoarthritis. We identified Raman spectroscopic markers of altered molecular structure in subchondral bone and relevant biological fluids. Using Raman spectroscopy the molecular structure of joint tissues was measured, and the results were compared to the results from micro computed tomographic and histopathologic analysis. Raman spectra of subchondral bone collected from Del1 (+/-) transgenic mice, a mouse model for early-onset osteoarthritis, indicated lower bone mineralization in transgenic mice (5.73 ± 0.28 vs. 6.87 ± 0.225 in wild-type mice, p=0.003). A fiber-optic Raman probe for arthroscopic measurements was developed to demonstrate the feasibility of measuring the molecular structure of joint tissue with clinically-relevant instrumentation. The carbonate-to-phosphate ratio, a Raman spectroscopic measurement of bone mineral composition, was measured from subchondral bone under an intact layer of cartilage. Our initial work on a human proximal radius specimen indicated that an arthroscope configuration is capable of providing similar carbonate-to-phosphate values as spectra collected on a Raman microscope (0.25 vs. 0.24). In addition to cartilage and subchondral bone, the chemical structure of synovial fluid molecules is a key factor in maintaining healthy joint function. Synovial fluid from normal and diseased joints was examined using a novel drop deposition/Raman spectroscopic method. Raman spectra of synovial fluid from patients with radiographic evidence of osteoarthritis showed evidence of altered protein structure, as shown by increased Raman band intensity ratios at 1080 cm-1/1002 cm-1 (0.054 ± 0.07 vs. 0.038 ± 0.003, p<0.01) and 1670 cm-1/1655 cm-1 (0.68 ± 0.06 vs. 0.51 ± 0.05, p<0.01). These studies show that Raman spectroscopic measurements of joint tissue and synovial fluid correlate with established techniques for osteoarthritis detection and Raman spectroscopy may potentially provide early detection of joint damage.Ph.D.Biomedical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/64589/1/kareshni_1.pd

Design of automatic milking system for use in pasture-based systems

End of Project ReportA commercial vision system was successful in identifying target artificial teats in various and demanding scenarios, but the system is very prone to making false identifications. A robotic manipulator capable of the simultaneous handling of four milking cups has been designed. The end-effector profile is sufficiently compact to allow access between the rear legs of the cow while enabling full access to all four teats for application of milking cups. The positioning response of the end-effecter is satisfactory for accommodating small changes in teat position during milking cup application

Raman Spectroscopy and Regenerative Medicine: A Review

The field of regenerative medicine spans a wide area of the biomedical landscape—from single cell culture in laboratories to human whole-organ transplantation. To ensure that research is transferrable from bench to bedside, it is critical that we are able to assess regenerative processes in cells, tissues, organs and patients at a biochemical level. Regeneration relies on a large number of biological factors, which can be perturbed using conventional bioanalytical techniques. A versatile, non-invasive, non-destructive technique for biochemical analysis would be invaluable for the study of regeneration; and Raman spectroscopy is a potential solution. Raman spectroscopy is an analytical method by which chemical data are obtained through the inelastic scattering of light. Since its discovery in the 1920s, physicists and chemists have used Raman scattering to investigate the chemical composition of a vast range of both liquid and solid materials. However, only in the last two decades has this form of spectroscopy been employed in biomedical research. Particularly relevant to regenerative medicine are recent studies illustrating its ability to characterise and discriminate between healthy and disease states in cells, tissue biopsies and in patients. This review will briefly outline the principles behind Raman spectroscopy and its variants, describe key examples of its applications to biomedicine, and consider areas of regenerative medicine that would benefit from this non-invasive bioanalytical tool

Chloroquine and Hydroxychloroquine for COVID-19: Demonstrating the Importance of the Scientific Process

Although chloroquine and hydroxychloroquine have been touted in the media as “miracle drugs” in the fight against COVID-19, the research backing this claim is controversial. Some studies have shown impressive results – like one study that reported a 100% cure rate – while numerous other studies have reported inefficacy. However, the evidence presented in many of these studies has been laden with glaring flaws – from low sample sizes to a lack of control group – and many had been pre-printed without peer review. No matter how contentious the evidence for efficacy may be, studies have shown an undeniable association with serious adverse events, most notably heart arrythmias. In this article, we will discuss where the hype originated, the current state of evidence, and where the future of these in drugs is headed in the current climate of COVID-19

Robust spectroscopic quantification in turbid media

This thesis explores four methods for improving quantitative diffuse reflectance spectroscopy in light scattering media. In the introduction theories of light propagation in scattering media, relevant instrumentation for measuring light scattering properties, spectral data processing methods, and spectroscopically active bioanalytes are outlined. Next, two novel instruments for practical scattering measurements, and two novel data processing techniques are presented. Finally, directions for future research into diffuse reflectance spectroscopy are suggested. A novel photon time-of-flight instrument is used to measure scattering coefficients in tandem with a portable diode spectrometer. Measured scattering coefficients are used to correct co-measured near infrared spectra for scattering and for improving quantification. Reduced scattering coefficients were measured with coefficients of variation of 11.6% at 850 nm and 14.1% at 905 nm. This allows practical correction of light scattering in point-spectra. Using scattering-correction, estimates of dye concentration were improved by 35%. A novel device imaging annular patterns is presented. This imaging instrument is used to measure reduced scattering coefficients and absorption coefficients. Reduced scattering coefficients were measured with a coefficient of variation of 12.6%, and absorption coefficients were measured with a coefficient of variation 50% lower than using traditional imaging methods. A novel method for using parsimony in the development of data processing methods using genetic algorithms is presented. Genetic algorithms have been used to identify spectroscopic data processing methods for complex samples. ACette thèse explore quatre méthodes pour l'amélioration de la spectroscopie de réflectance diffuse quantitative dans des milieux qui diffusent la lumière. En introduction, une description des théories de la propagation de la lumière dans des médias qui diffusent celle-ci, des instruments pour mesurer les propriétés de diffusion, des méthodes de traitement des données spectrales, et des bioanalytes avec activité optique est donné. Un nouvel appareil à «temps de vol de photon» est présenté. Cet instrument portatif est utilisé pour mesurer le coefficient de dispersion en tandem avec un spectromètre à diode portable. Les coefficients de diffusion mesurés sont ensuite utilisés pour corriger la dispersion dans les spectres infrarouges co-mesurée, ainsi que l'amélioration de la quantification. Les coefficients de dispersion ont été mesurés avec une variation de 11,6% à 850 nm et 14,1% à 905 nm. En prenant en compte la dispersion, les estimations de la concentration de teinture ont été améliorées de 35%. Un nouvel appareil utilisant les modes d'imagerie annulaire pour mesurer les coefficients de dispersion et d'absorption est présenté. Les coefficients de dispersion ont été mesurés avec un coefficient de variation de 12,6%, et les coefficients d'absorption ont été mesurés avec un coefficient de variation amélioré de 50% par rapport aux méthodes d'imagerie traditionnelle. Une nouvelle méthode pour améliorer l'utilisation des mesures de simplicité dans le développement de méthodes de traitement des données via des algorithmes génétiques est présentée. Les algorithmes génétiques ont été utilisés pour identifier les mé