Podcasts about infrared spectroscopy

Question and Response #60 New College-Style Sweatshirt! In this episode of 'Ask a Chemist' on the Chemistry for Your Life podcast, hosts Melissa and Jam tackle a diverse range of fun and fascinating chemistry questions. Topics include the differences between oxygen in water and air, the properties of jello, the mystery behind glitter, and the impact of pasteurization on milk safety. The episode also addresses more complex inquiries such as infrared spectroscopy and the oxidative stability of whole grain flour. 00:00 Introduction to Ask a Chemist 02:39 The Pasteurization Question 08:51 What Makes Jello Jello? 10:06 Oxygen in Water vs. Air 12:40 The Mystery of Glitter 15:46 Infrared Spectroscopy and Northern Lights 18:29 Oxidation in Flour 22:17 Collagen and Muscle Building 26:06 Listener Reviews and Closing Remarks References from this episode: https://www.maastrichtuniversity.nl/l.vanloon We want to give a special thanks to Bri McAllister for illustrating molecules for some episodes! Please go check out Bri's art, follow and support her at entr0pic.artstation.com and @McAllisterBri on twitter!   Thanks to our monthly supporters Autoclave Chelsea M Dorien V Scott B Jessie Reder Ciara Linville J0HNTR0Y Jeannette Napoleon Cullyn R Erica Bee Elizabeth P Sarah Moar Rachel Reina Letila Katrina Barnum-Huckins Suzanne Phillips Venus Rebholz Lyn Stubblefield Jacob Taber Brian Kimball Emerson Woodhall Kristina Gotfredsen Timothy Parker Steven Boyles Chris Skupien Chelsea B Bri McAllister Avishai Barnoy Hunter Reardon ★ Support this podcast on Patreon ★ ★ Buy Podcast Merch and Apparel ★ Check out our website at chemforyourlife.com Watch our episodes on YouTube Find us on Instagram, Twitter, and Facebook @ChemForYourLife

If you work in the medical field, you may be familiar with Functional Near-Infrared Spectroscopy (fNIRS). “Functional near-infrared spectroscopy (fNIRS) is a portable, non-invasive, brain imaging technology that uses low levels of non-ionizing light to record changes in cerebral blood flow in the brain through optical sensors placed on the surface of the scalp,” according […]

Michael Gray is the CEO of Actus Analytical, Inc., which develops spectroscopy solutions for public safety compliance, illicit drug detection, agricultural productivity, and other applications. Michael and his wife Nancy founded The Actus Foundation, a 501(c)(3) charitable organization, in 2018. The Actus Foundation advocates for solutions to treating the entirety of the overdose epidemic problem in America, including the largely forgotten constituency of intermittent users. He founded, with partner Ed Kobilis in 2019, the Fentanyl Awareness Coalition - a coalition of tens of thousands of advocates in the US. Michael is a popular speaker, offering unique analyses and suggestions for creative solutions to a new problem, i.e., an old problem with a recently altered paradigm. Michael walks participants through the murky world of the drug problem clarifying the threat and dispelling myths. The Actus Foundation also advocates for the mentally ill, striving to deliver the message that mental illness is a disease the entire family suffers, and suffers in isolation; there are no well-worn paths to solutions available to those in chronic states of mental illness. For all our success in medical science – diagnostic practices, treatment/care and patient advocacy – our nation has left behavioral science in the stone age. Our practice of psychiatric care – diagnostic practices, treatment/care and patient advocacy – is the ugly stepchild hidden in the attic as the country proudly displays her medical science wonders to the world. In addition to advocacy, Mr. Gray is offering his 35 years of professional expertise in the world of scientific instrumentation as another element of his work on behalf of the victims of overdose. As the Interdict Law and other legislative activity considers nascent technological advances in the ability to detect illicit drugs at the street level, Michael adds his professional expertise to that debate. With experience in the areas of Infrared Spectroscopy and Mass Spectrometry, Michael is participating in the development and deployment of portable testing for narcotics, at the field level, as a means of confirming suspected illegal substances and protecting First Responders. HELP SUPPORT OUR FIGHT AGAINST ADDICTION. DONATE HERE: https://www.patreon.com/theaddictionpodcast   PART OF THE GOOD NEWS PODCAST NETWORK. AUDIO VERSIONS OF ALL OUR EPISODES: https://theaddictionpodcast.com CONTACT US: The Addiction Podcast - Point of No Return theaddictionpodcast@yahoo.com Intro and Outro music by: Decisions by Kevin MacLeod is licensed under a Creative Commons Attribution 4.0 license. https://creativecommons.org/licenses/by/4.0/ Source: http://incompetech.com/music/royalty-free/index.html?isrc=USUAN1100756 Artist: http://incompetech.com/

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.03.05.531176v1?rss=1 Authors: Walczak, E. J. Abstract: Speech-Induced Suppression (SIS) is a suppression of brain activity by speech. It is believed to be caused by the internal predictions of the consequences of speech movements which lead to attenuation of related neural activity. Previous research showed that SIS of the EEG signal can be observed in some speaking tasks but the results were not consistent. This study found that fNIRS can be used to test neural activity related to speech production. Grand averaged signals showed that conditions involving vocalisation actually elicited higher activity than those without vocalisation. When statistical models were fitted to the obtained data, and controlled for participant-related variation, these results did not hold. No statistically significant differences between conditions were found. Even though haemoglobin concentration changes are slower than ERPs, they capture the neural activity underlying speech-production processes. The current results suggest that fNIRS can be used to study speech production. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

Near-Infrared Spectroscopy of Ultracompact ion H 2 regions in W51A with NIFS ALTAIR by Cassio L. Barbosa et al. on Monday 28 November W51A is the most active star formation region of the Giant ion{H}{2} region W51. It harbors the two massive proto-clusters W51e and W51,IRS2, which are very rare in the Galaxy. We aim to identify the new born massive stars and UCHII regions to derive its distance and age. We performed IFU observations with NIFS+ALTAIR of nine targets in the W51A sub-region. The distance modulus was obtained using the spectral classification in the $K$-band and a reddening law appropriate to the inner Galactic plane. We derived the distance and the spectral types for five of them, ranging from O8 to O9.5, similar to those derived from radio continuum data, except for two sources that we assigned somewhat a later spectral type. We included another seven objects with precise spectral classification from other works, which allowed us to better constrain the distance estimate. Our spectrophotometric distance d=4.80,$pm$,1.27,kpc is in good agreement with those derived from the Galactic rotation model and trigonometric parallaxes, placing the region near the tangent point of the Sagittarius arm. We conclude that the stars studied in this work have an age spread of 1.5-4 Myr, substantially older than thought to date. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.13841v1

Near-Infrared Spectroscopy of Ultracompact ion H 2 regions in W51A with NIFS ALTAIR by Cassio L. Barbosa et al. on Sunday 27 November W51A is the most active star formation region of the Giant ion{H}{2} region W51. It harbors the two massive proto-clusters W51e and W51,IRS2, which are very rare in the Galaxy. We aim to identify the new born massive stars and UCHII regions to derive its distance and age. We performed IFU observations with NIFS+ALTAIR of nine targets in the W51A sub-region. The distance modulus was obtained using the spectral classification in the $K$-band and a reddening law appropriate to the inner Galactic plane. We derived the distance and the spectral types for five of them, ranging from O8 to O9.5, similar to those derived from radio continuum data, except for two sources that we assigned somewhat a later spectral type. We included another seven objects with precise spectral classification from other works, which allowed us to better constrain the distance estimate. Our spectrophotometric distance d=4.80,$pm$,1.27,kpc is in good agreement with those derived from the Galactic rotation model and trigonometric parallaxes, placing the region near the tangent point of the Sagittarius arm. We conclude that the stars studied in this work have an age spread of 1.5-4 Myr, substantially older than thought to date. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.13841v1

Michael Gray is the CEO of Actus Analytical, Inc., which develops spectroscopy solutions for public safety compliance, illicit drug detection, agricultural productivity, and other applications. Michael and his wife Nancy founded The Actus Foundation, a 501(c)(3) charitable organization, in 2018. The Actus Foundation advocates for solutions to treating the entirety of the overdose epidemic problem in America, including the largely forgotten constituency of intermittent users. He founded, with partner Ed Kobilis in 2019, the Fentanyl Awareness Coalition - a coalition of tens of thousands of advocates in the US.  Michael is a popular speaker, offering unique analyses and suggestions for creative solutions to a new problem, i.e., an old problem with a recently altered paradigm. Michael walks participants through the murky world of the drug problem clarifying the threat and dispelling myths.    The Actus Foundation also advocates for the mentally ill, striving to deliver the message that mental illness is a disease the entire family suffers, and suffers in isolation; there are no well-worn paths to solutions available to those in chronic states of mental illness. For all our success in medical science – diagnostic practices, treatment/care and patient advocacy – our nation has left behavioral science in the stone age. Our practice of psychiatric care – diagnostic practices, treatment/care and patient advocacy – is the ugly stepchild hidden in the attic as the country proudly displays her medical science wonders to the world.   In addition to advocacy, Mr. Gray is offering his 35 years of professional expertise in the world of scientific instrumentation as another element of his work on behalf of the victims of overdose. As the Interdict Law and other legislative activity considers nascent technological advances in the ability to detect illicit drugs at the street level, Michael adds his professional expertise to that debate. With experience in the areas of Infrared Spectroscopy and Mass Spectrometry, Michael is participating in the development and deployment of portable testing for narcotics, at the field level, as a means of confirming suspected illegal substances and protecting First Responders.

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2022.10.02.510532v1?rss=1 Authors: Takahashi, S., Grove, P. M. Abstract: A growing body of literature demonstrates that a single bout of exercise benefits executive function. While the acute effect of simple exercises like walking, running, and cycling has been well investigated, it is less clear how complex exercise, which requires open skills and various motions, impacts executive function and brain activation. Therefore, we compared the acute effects of a complex exercise on inhibitory control and brain activation with those of a simple exercise using functional near-infrared spectroscopy (fNIRS). Twenty-four young right-hand dominant adults (9 women) completed three interventions: badminton, running, and a seated rest control condition for 10 min each. During each intervention, oxygen uptake and heart rate were monitored. A Stroop task composed of neutral and incongruent conditions was administrated before and after each intervention. An fNIRS system recorded hemodynamics in the prefrontal cortex to evaluate brain activation during the Stroop task. The intensities of badminton and running were comparable. Performance on the Stroop task was significantly improved after badminton, specifically in the incongruent condition relative to in the neutral condition. On the other hand, neither running nor seated rest affected performance in the Stroop task. The fNIRS measures indicated that badminton and running had no significant influence on brain activation. These results show that a single bout of complex exercise enhances inhibitory control without increasing brain activation compared to simple exercise, suggesting that an acute complex exercise induces neural efficiency. Copy rights belong to original authors. Visit the link for more info Podcast created by PaperPlayer

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2022.09.30.510216v1?rss=1 Authors: Shoaib, Z., Chang, W. K., Lee, J., Lee, S. H., Phillips, Z., Lee, S. H., Paik, N.-J., Hwang, H.-J., Kim, W.-S. Abstract: Background: Cerebellar brain inhibition (CBI), a neural connection between the cerebellum and primary motor cortex (M1), has been researched as a target pathway for neuromodulation to improve clinical outcomes in various neurological diseases. However, conflicting results of anodal cerebellar transcranial direct current stimulation (acb-tDCS) on M1 excitability indicate that additional investigation is required to examine its precise effect. Objective/Hypothesis: This study aimed to gather evidence of the neuromodulatory effect of acb-tDCS on the M1 using functional near-infrared spectroscopy (fNIRS). Methods: Sixteen healthy participants were included in this cross-over study. Participants received real and sham acb-tDCS in a random order, with a minimum one-week washout period between them. The anode and cathode were placed on the right cerebellum and the right buccinator muscle, respectively. Stimulation lasted 20 min at an intensity of 2 mA, and fNIRS data were recorded for 42 min (including a 4 min baseline before stimulation and an 18 min post-stimulation duration) using eight channels attached bilaterally on the M1. Results: acb-tDCS induced a significant decrease in oxyhemoglobin (HbO) concentration (inhibitory effect) in the left (contralateral) M1, whereas it induced a significant increase in HbO concentration (excitatory effect) in the right (ipsilateral) M1 compared to sham tDCS during (p less than 0.05) and after stimulation (p less than 0.01) in a group level analysis. At the individual level, variations in the response to acb-tDCS were observed. Conclusion: Our findings demonstrate the neuromodulatory effects of acb-tDCS on the bilateral M1 in terms of neuronal hemodynamics. Copy rights belong to original authors. Visit the link for more info Podcast created by PaperPlayer

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2022.08.30.505941v1?rss=1 Authors: Wong, A., Bhuiyan, M. I. H., Rothman, J., Drew, K., Pourrezaei, K., Sun, D., Barati, Z. Abstract: Timely and sensitive in vivo estimation of ischemic stroke-induced brain infarction are necessary to guide diagnosis and evaluation of treatments efficacy. The gold standard for estimation of the cerebral infarction volume is magnetic resonance imaging (MRI), which is expensive and not readily accessible. Measuring regional cerebral blood flow (rCBF) with Laser Doppler flowmetry (LDF) is the status quo for confirming reduced blood flow in experimental ischemic stroke models. However, rCBF reduction following cerebral artery occlusion often does not correlate with subsequent infarct volume. In the present study, we employed the continuous-wave near infrared spectroscopy (NIRS) technique to monitor cerebral oxygenation during 90 min of the intraluminal middle cerebral artery occlusion (MCAO) in Sprague-Dawley rats (n=8, male). The NIRS device consisted of a controller module and an optical sensor with two LED light sources and two photodiodes making up two parallel channels for monitoring left and right cerebral hemispheres. Optical intensity measurements were converted to deoxyhemoglobin (Hb) and oxyhemoglobin (HbO2) changes relative to a 2-min window prior to MCAO. Area under the curve (auc) for Hb and HbO2 was calculated for the 90-min occlusion period for each hemisphere (ipsilateral and contralateral). To obtain a measure of total ischemia, auc of the contralateral side was subtracted from the ipsilateral side resulting in {Delta}Hb and {Delta}HbO2 parameters. Infarct volume (IV) was calculated by triphenyl tetrazolium chloride (TTC) staining at 24h reperfusion. Results showed a significant negative correlation (r = -0.81, p = 0.03) between {Delta}Hb and infarct volume. In conclusion, our results show feasibility of using a noninvasive optical imaging instrument, namely NIRS, in monitoring cerebral ischemia in a rodent stroke model. This cost-effective, non-invasive technique may improve the rigor of experimental models of ischemic stroke by enabling in vivo longitudinal assessment of cerebral oxygenation and ischemic injury. Copy rights belong to original authors. Visit the link for more info Podcast created by PaperPlayer

In this podcast, we discuss the article 'Functional near-infrared spectroscopy to assess pain in neonatal circumcisions'. We hope you enjoy.

Near infrared spectroscopy (NIRS) ... 'a variation of pulse oximetry; it transmits red and infrared light into tissue' measures information from arterial venous and capillary blood simultaneously to deduce tissue saturation; an aggregate estimate of arteriovenous capillary blood and whatever tissue you're shining the light into. 'So typically, we're using it in on the brain at least in the cardiac and vascular space, but people also in other areas like the surgical ICU, can use it to measure muscle oxygenation as well'. Learn how this technique could enhance your practice, what its potential for advancement is and where its limits lie. This piece is likely to be of critical interest to most cardiac surgeons and those who work alongside them. This piece was generously supported and brought to you by Medtronic. Presented by Desiree Chappell and Monty Mythen with their guests Robert Thiele, Cardiac Anesthesiologist and Intensivist at the University of Virginia, Carol Ann Rosenberg Associate Director of Perfusion and ECMO, Kenan Yount, Cardiac Surgeon and Director of the Valve center and Director of the Aortic Center at the University of Virginia.

Near infrared spectroscopy (NIRS) ... 'a variation of pulse oximetry; it transmits red and infrared light into tissue' measures information from arterial venous and capillary blood simultaneously to deduce tissue saturation; an aggregate estimate of arteriovenous capillary blood and whatever tissue you're shining the light into. 'So typically, we're using it in on the brain at least in the cardiac and vascular space, but people also in other areas like the surgical ICU, can use it to measure muscle oxygenation as well'. Learn how this technique could enhance your practice, what its potential for advancement is and where its limits lie. This piece is likely to be of critical interest to most cardiac surgeons and those who work alongside them. This piece was generously supported and brought to you by Medtronic. Presented by Desiree Chappell and Monty Mythen with their guests Robert Thiele, Cardiac Anesthesiologist and Intensivist at the University of Virginia, Carol Ann Rosenberg, Associate Director of Perfusion and ECMO, Kenan Yount, Cardiac Surgeon and Director of the Valve center and Director of the Aortic Center at the University of Virginia.

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.09.27.315390v1?rss=1 Authors: Benitez-Andonegui, A., Luhrs, M., Nagels-Coune, L., Ivanov, D., Goebel, R., Sorger, B. Abstract: Designing optode layouts is an essential step for functional near-infrared spectroscopy (fNIRS) experiments as the quality of the measured signal and the sensitivity to cortical regions-of-interest depend on how optodes are arranged on the scalp. This becomes particularly relevant for fNIRS-based brain-computer interfaces (BCIs), where developing robust systems with few optodes is crucial for clinical applications. Available resources often dictate the approach researchers use for optode-layout design. Here we compared four approaches that incrementally incorporated subject-specific magnetic resonance imaging (MRI) information while participants performed mental-calculation, mental-rotation and inner-speech tasks. The literature-based approach (LIT) used a literature review to guide the optode layout design. The probabilistic approach (PROB), employed individual anatomical data and probabilistic maps of functional MRI (fMRI)-activation from an independent dataset. The individual fMRI (iFMRI) approach used individual anatomical and fMRI data, and the fourth approach used individual anatomical, functional and vascular information of the same subject (fVASC). The four approaches resulted in different optode layouts and the more informed approaches outperformed the minimally informed approach (LIT) in terms of signal quality and sensitivity. Further, PROB, iFMRI and fVASC approaches resulted in a similar outcome. We conclude that additional individual MRI data leads to a better outcome, but that not all the modalities tested here are required to achieve a robust setup. Finally, we give preliminary advice to efficiently using resources for developing robust optode layouts for BCI and neurofeedback applications. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.07.23.217760v1?rss=1 Authors: Debracque, C., Gruber, T., Lacoste, R., Grandjean, D., Meguerditchian, A. Abstract: Hemispheric asymmetries have long been seen as characterizing the human brain; yet, an increasing number of reports suggest the presence of such brain asymmetries in our closest primate relatives. However, most available data in non-human primates have so far been acquired as part of neurostructural approaches such as MRI, while comparative data in humans are often dynamically acquired as part of neurofunctional studies. In the present exploratory study in baboons (Papio Anubis), we tested whether brain lateralization could be recorded non-invasively using a functional Near-Infrared Spectroscopy (fNIRS) device in two contexts: motor and auditory passive stimulations. Under light propofol anaesthesia monitoring, three adult female baboons were exposed to a series of (1) left- versus right-arm passive movement stimulations; and (2) left- versus right-ear versus stereo auditory stimulations while recording fNIRS signals in the related brain areas (i.e., motor central sulcus and superior temporal cortices respectively). For the motor condition our results show that left-arm versus right-arm stimulations induced typical contralateral difference in hemispheric activation asymmetries in the three subjects for all three channels. For the auditory condition, we also revealed typical human-like patterns of hemispheric asymmetries in one subject for all three channels, namely (1) typical contralateral differences in hemispheric asymmetry between left-ear versus right-ear stimulations, and (2) a rightward asymmetry for stereo stimulations. Overall, our findings support the use of fNIRS to investigate brain processing in non-human primates from a functional perspective, opening the way for the development of non-invasive procedures in non-human primate brain research. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.06.04.129205v1?rss=1 Authors: Steinmetzger, K., Shen, Z., Riedel, H., Rupp, A. Abstract: To validate the use of functional near-infrared spectroscopy (fNIRS) in auditory perception experiments, combined fNIRS and electroencephalography (EEG) data were obtained from normal-hearing subjects passively listening to speech-like stimuli without linguistic content. The fNIRS oxy-haemoglobin (HbO) results were found to be inconsistent with the deoxy-haemoglobin (HbR) and EEG data, as they were dominated by pronounced cerebral blood stealing in anterior-to-posterior direction. This large-scale bilateral gradient in the HbO data masked the right-lateralised neural activity in the auditory cortex that was clearly evident in the HbR data and EEG source reconstructions. When the subjects were subsequently split into subgroups with more positive or more negative HbO responses in the right auditory cortex, the former group surprisingly showed smaller event-related potentials, less activity in frontal cortex, and increased EEG alpha power, all indicating reduced attention and vigilance. These findings thus suggest that positive HbO responses in the auditory cortex may not necessarily be a favourable result when investigating auditory perception using fNIRS. More generally, the results show that the interpretation of fNIRS HbO signals can be misleading and demonstrate the benefits of combined fNIRS-EEG analyses in resolving this issue. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.05.24.113928v1?rss=1 Authors: Rezaee, Z., Ranjan, S., Solanki, D., Bhattacharya, M., Srivastava, M. P., Lahiri, U., Dutta, A. Abstract: Cerebellar transcranial direct current stimulation (ctDCS) can facilitate motor learning; however, ctDCS effects have not been investigated using portable neuroimaging vis-a-vis lobular electric field strength. This is important since the subject-specific residual architecture for cerebellar interconnections with the cerebral cortex, including the prefrontal cortex (PFC) and the sensorimotor cortex (SMC), can influence the ctDCS effects on the cerebral functional activation. In this study, we investigated functional near-infrared spectroscopy (fNIRS) in conjunction with electroencephalography (EEG) to measure the changes in the brain activation at the PFC and the SMC following virtual reality (VR)-based Balance Training (VBaT), before and after ctDCS treatment in 12 hemiparetic chronic stroke survivors. Furthermore, we performed general linear modeling (GLM) that can putatively associate the lobular electric field strength due to ctDCS priming with the changes in the fNIRS-EEG measures in the chronic stroke survivors. Here, fNIRS-EEG based measures were investigated in their latent space found using canonical correlation analysis (CCA) that is postulated to capture neurovascular coupling. We found that the ctDCS electrode montage, as well as the state (pre-intervention, during intervention, post-intervention), had a significant (p

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This episode covers the physics behind pulse oximetry. It goes over how we can use the different absorption spectra of oxygenated and deoxygenated haemoglobin to determine their relative concentrations and therefore a saturation. We then talk about the common issues that we encounter when using pulse oximetry in clinical practice. A good episode to listen to before this one is Infrared Spectroscopy and Capnography. It covers the principle of infrared absorption in more detail. If you have any questions or comments, please leave them on the website planaprimary.co.uk or email me at questions@planaprimary.co.uk. This podcast is completely free, so please share it with anyone who you think might find it useful.

This episode we're covering Infrared Spectroscopy and Capnography. We'll go over why certain molecules absorb infrared light, the Beer-Lambert Law and some of the key values for the main gases that we measure in anaesthetics. We'll then cover Capnography equipment and the differences between main stream and side stream analysers. If you have any questions, comments or requests, please contact me at questions@planaprimary.co.uk

University of Tübingen postdoc, Ujwal Chaudhary, and I talk about some of his techniques to unlock patients who are locked in. Those who are paralyzed and cannot move their hands or eyes can have a small non-invasive Near Infrared device placed on their head to be able to decipher binary yes and no answers. The technique measures the level of blood oxygenation in the brain which can signify what a patient might be thinking. With this technology, they are able to be correct about 70% of the time. The technology is essentially an fMRI which is much more portable and less costly.

Commentary by Dr. Valentin Fuster

Presented by Adré du Plessis, MB ChB

Presented by Istvan Seri, MD, PhD

Presented by Michael D. Wider, PhD

Presented by Adré du Plessis, MB ChB

Presented by Adnan Bhutta, MD

Presented by Michael Wider, PhD

This video is part of a 28-lecture graduate-level course titled "Organic Spectroscopy" taught at UC Irvine by Professor James S. Nowick. The course covers infrared (IR) spectroscopy, mass spectrometry, and nuclear magnetic resonance (NMR) spectroscopy, the latter of which is the main focus. Topics covered in the NMR spectroscopy part of the course include chemical shifts, spin-spin coupling, dynamic effects in NMR spectroscopy, and 2D NMR spectroscopy (COSY, HMQC, HMBC, TOCSY, NOESY, ROESY). Any questions or concerns regarding this class, please e-mail: jsnowick at uci.edu. Copyright © 2011 The Regents of the University of California All Rights Reserved Filmed by the Teaching, Learning, and Technology Center CC-BY-SA

MS theory; interpretation of mass spectra; IR theory, interpretation of IR spectra

Preparing samples for infra-red spectroscopy

Transcript -- Preparing samples for infra-red spectroscopy

Preparing samples for infra-red spectroscopy

Transcript -- Preparing samples for infra-red spectroscopy

Fourier-transform infrared difference spectra between the red-absorbing and far-red-absorbing forms of oat phytochrome have been measured in H2O and 2H2O. The difference spectra are compared with infrared spectra of model compounds, i.e. the (5Z,10Z,15Z)- and (5Z,10Z,15E)-isomers of 2,3,7,8,12,13,17,18-octaethyl-bilindion (Et8-bilindion), 2,3-dihydro-2,3,7,8,12,13,17,18-octaethyl-bilindion (H2Et8-bilindion), and protonated H2Et8-bilindion in various solvents. The spectra of the model compounds show that only for the protonated forms can clear differences between the two isomers be detected. Since considerable differences are present between the spectra of Et8-bilindion and H2Et8-bilindion, it is concluded that only the latter compound can serve as a model system of phytochrome. The 2H2O effect on the difference spectrum of phytochrome supports the view that the chromophore in red-absorbing phytochrome is protonated and suggests, in addition, that it is also protonated in far-red-absorbing phytochrome. The spectra show that protonated carboxyl groups are influenced. The small amplitudes in the difference spectra exclude major changes of protein secondary structure.