FT-IR spectra of 90 K films of simple, mixed, and double clathrate hydrates of trimethylene oxide, methyl chloride, carbon dioxide, tetrahydrofuran, and ethylene oxide containing decoupled water-d2

1988 ◽  
Vol 92 (3) ◽  
pp. 631-635 ◽  
Author(s):  
Fouad Fleyfel ◽  
J. Paul Devlin
Keyword(s):  
Carbon Dioxide ◽  
Ethylene Oxide ◽  
Ir Spectra ◽  
Methyl Chloride ◽  
Clathrate Hydrates ◽  
Trimethylene Oxide ◽  
Ft Ir

FT‐IR spectra of vacuum deposited clathrate hydrates of oxirane H2S, THF, and ethane

1985 ◽  
Vol 83 (9) ◽  
pp. 4387-4394 ◽  
Author(s):  
Hugh H. Richardson ◽  
Paul J. Wooldridge ◽  
J. Paul Devlin
Keyword(s):  
Ir Spectra ◽  
Clathrate Hydrates ◽  
Ft Ir

FT-IR spectra of carbon dioxide clusters

1989 ◽  
Vol 93 (21) ◽  
pp. 7292-7294 ◽  
Author(s):  
Fouad Fleyfel ◽  
J. Paul Devlin
Keyword(s):  
Carbon Dioxide ◽  
Ir Spectra ◽  
Ft Ir ◽  
Carbon Dioxide Clusters

FT-IR SPECTRA OF VACUUM DEPOSITED CLATHRATE HYDRATES OF OXIRANE, H2S, THF, ETHANE AND CYCLOPROPANE

1987 ◽  
Vol 48 (C1) ◽  
pp. C1-685-C1-685
Author(s):  
H. H. RICHARDSON ◽  
P. J. WOOLDRIDGE ◽  
J . P . DEVLIN
Keyword(s):  
Ir Spectra ◽  
Clathrate Hydrates ◽  
Ft Ir

Far infrared absorption and rotational vibrations of the guest molecules in structure I clathrate hydrates between 4.3 and 100 K

1977 ◽  
Vol 55 (10) ◽  
pp. 1777-1785 ◽  
Author(s):  
John E. Bertie ◽  
Stephen M. Jacobs
Keyword(s):  
Ethylene Oxide ◽  
Guest Molecule ◽  
Signal To Noise Ratio ◽  
Michelson Interferometer ◽  
Far Infrared ◽  
Force Constants ◽  
Clathrate Hydrates ◽  
High Signal ◽  
Guest Molecules ◽  
Trimethylene Oxide

The infrared spectra between 330 and 15 cm−1 of the structure I clathrate hydrates of ethylene oxide, cyclopropane, and trimethylene oxide, at 4.3 K are presented. The spectra have an unusually high signal-to-noise ratio made possible by a Michelson interferometer and a silicon bolometer detector which operates at 1.2 K. Rotational vibrations of the guest molecules were observed at 65.0 and 35.6 cm−1 for ethylene oxide and at 69 and 50 cm−1 for trimethylene oxide. Inter-guest coupling of rotational vibrations is small and the two frequencies are assigned to vibrations about different inertial axes. The resulting force constants are 487 and 264 ferg rad−2 for ethylene oxide and 1190 and 1130 ferg rad−2 for trimethylene oxide and are discussed in relation to the barriers to reorientation of the guest molecule. The bands due to these vibrations are fairly sharp at 4.3 K, but are broad and poorly defined at 100 K. The guest and water vibrations interact predominantly through their transition dipoles, although the main contribution to the force constants of the rotational vibrations is from steric forces. The absorption by the water vibrations above 100 cm−1 is very similar for ethylene oxide and cyclopropane hydrates but significantly different for trimethylene oxide hydrate. Strong objections exist to the obvious interpretations of this difference which remains unexplained.

Carbon Dioxide Clathrates: An IR Spectroscopic Marker for Arthritis?

1993 ◽  
Vol 47 (9) ◽  
pp. 1519-1521 ◽  
Author(s):  
Hans H. Eysel ◽  
Michael Jackson ◽  
Henry H. Mantsch ◽  
Glen T. D. Thomson
Keyword(s):  
Carbon Dioxide ◽  
Synovial Fluid ◽  
Ir Spectra ◽  
Clinical Diagnosis ◽  
The State ◽  
Clathrate Hydrates ◽  
State Of Health ◽  
Biological Media ◽  
Ir Spectroscopic ◽  
Arthritic Joints

The IR spectra of dry films of synovial fluid from normal and arthritic joints are presented. The spectra suggest the existence of CO2 clathrates in these fluids which are of remarkable stability in comparison to well-known CO2 clathrate hydrates. To our knowledge, this is the first demonstration of the formation of CO2 clathrates in biological media. The proportion of CO2 clathrates found in synovial fluid appears to vary with the state of health of joints and thus may be of use in the clinical diagnosis of arthritis.

Light- or Dark-Colored, L-DOPA-Based Melanins

2018 ◽  
Author(s):  
Koen Vercruysse ◽  
Margaret M. Whalen
Keyword(s):  
Human Physiology ◽  
Ir Spectra ◽  
Immune Cells ◽  
Chemical Properties ◽  
Chemical Signature ◽  
Ft Ir

<p>This report is a continuation of previous research on the H<sub>2</sub>O<sub>2</sub>-mediated synthesis of melanin-like pigments. We synthesized and characterized L-DOPA-based pigments using air- or H<sub>2</sub>O<sub>2</sub>-mediated<sub> </sub>oxidation. We compared their physic-chemical properties and evaluated their capacity to affect the interleukin release from immune cells. The use of higher concentrations of H<sub>2</sub>O<sub>2</sub> resulted in melanin-like materials with a distinct chemical signature in their FT-IR spectra and a lighter color. All pigments enhanced the interleukin release from immune cells. The possibility that lighter-colored melanins can be generated is discussed in the context of the importance of melanin-based pigmentation in human physiology.</p>

scholarly journals Spectroscopy as a useful tool for the identification of changes with time in post-mortem vitreous humor for forensic toxicology purposes

2021 ◽  
Author(s):  
Anna Wójtowicz ◽  
Agata Mitura ◽  
Renata Wietecha-Posłuszny ◽  
Rafał Kurczab ◽  
Marcin Zawadzki
Keyword(s):  
Ir Spectra ◽  
Forensic Toxicology ◽  
Principal Component ◽  
Hierarchical Cluster ◽  
Vitreous Humor ◽  
Attenuated Total Reflection ◽  
Glass Slides ◽  
Added Benefit ◽  
Ft Ir ◽  
Non Destructive

AbstractVitreous humor (VH) is an alternative biological matrix with a great advantage of longer availability for analysis due to the lack of many enzymes. The use of VH in forensic toxicology may have an added benefit, however, this application requires rapid, simple, non-destructive, and relatively portable analytical analysis methods. These requirements may be met by Fourier transform infrared spectroscopy technique (FT-IR) equipped with attenuated total reflection accessory (ATR). FT-IR spectra of vitreous humor samples, deposited on glass slides, were collected and subsequent chemometric data analysis by means of Hierarchical Cluster Analysis and Principal Component Analysis was conducted. Differences between animal and human VH samples and human VH samples stored for diverse periods of time were detected. A kinetic study of changes in the VH composition up to 2 weeks showed the distinction of FT-IR spectra collected on the 1st and 14th day of storage. In addition, data obtained for the most recent human vitreous humor samples—collected 3 and 2 years before the study, presented successful discrimination of all time points studied. The method introduced was unable to detect mephedrone addition to VH in the concentration of 10 µg/cm3. Graphic abstract

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