scholarly journals Experimental induction of resins as a tool to understand variability in ambers

Fossil Record ◽  
2021 ◽  
Vol 24 (2) ◽  
pp. 321-337
Author(s):  
Leyla J. Seyfullah ◽  
Emily A. Roberts ◽  
Phillip E. Jardine ◽  
Alexander R. Schmidt
Keyword(s):  
Genetic Diversity ◽  
Multivariate Analyses ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Natural Resin ◽  
Experimental Induction ◽  
Chemical Signatures ◽  
Chemical Variability ◽  
Source Plant ◽  
Atr Spectroscopy

Abstract. Amber is chiefly known as a preservational medium of biological inclusions, but it is itself a chemofossil, comprised of fossilised plant resin. The chemistry of today's resins has been long investigated as a means of understanding the botanical sources of ambers. However, little is known about the chemical variability of resins and consequently about that of the ambers that are derived from particular resins. We undertook experimental resin production in Araucariacean plants to clarify how much natural resin variability is present in two species, Agathis australis and Wollemia nobilis, and whether different resin exudation stimuli types can be chemically identified and differentiated. The latter were tested on the plants, and the resin exudates were collected and investigated with Fourier-transform infrared attenuated total reflection (FTIR-ATR) spectroscopy to give an overview of their chemistry for comparisons, including multivariate analyses. The Araucariacean resins tested did not show distinct chemical signatures linked to a particular resin-inducing treatment. Nonetheless, we did detect two separate groupings of the treatments for Agathis, in which the branch removal treatment and mimicked insect-boring treatment-derived resin spectra were more different from the resin spectra derived from other treatments. This appears linked to the lower resin viscosities observed in the branch- and insect-treatment-derived resins. However the resins, no matter the treatment, could be distinguished from both species. The effect of genetic variation was also considered using the same stimuli on both the seed-grown A. australis derived from wild-collected populations and on clonally derived W. nobilis plants with natural minimal genetic diversity. The variability in the resin chemistries collected did reflect the genetic variability of the source plant. We suggest that this natural variability needs to be taken into account when testing resin and amber chemistries in the future.

Innovative Substrate-Integrated Hollow Waveguide Coupled Attenuated Total Reflection Sensors for Quantum Cascade Laser Based Infrared Spectroscopy in Harsh Environments

2021 ◽  
pp. 000370282110643
Author(s):  
Andrea Teuber ◽  
Robert Stach ◽  
Julian Haas ◽  
Boris Mizaikoff
Keyword(s):  
Quantum Cascade Lasers ◽  
Evanescent Field ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Ir Radiation ◽  
Metal Structures ◽  
Quantum Cascade ◽  
Hollow Waveguides ◽  
Optical Alignment ◽  
Atr Spectroscopy

An innovative mid-infrared spectroscopic sensor system based on quantum cascade lasers has been developed. The system combines the versatility of substrate-integrated hollow waveguides (IHWGs) with the robustness of attenuated total reflection (ATR) crystals employed as internal reflection waveguides for evanescent field sensing. IHWGs are highly reflective metal structures that propagate infrared (IR) radiation and were used as light pipes for coupling radiation into the ATR waveguide. The combined IHWG-ATR device has been designed such that the utmost stability and robustness of the optical alignment were ensured. This novel assembly enables evanescent field absorption measurements at yet unprecedently harsh conditions, that is, high pressure and temperature. Combining these advantages, this innovative sensor assembly is perfectly suited for taking ATR spectroscopy into the field where the robustness of the assembly and optical alignment is essential.

On the Nature of the Evanescent Wave

2013 ◽  
Vol 67 (2) ◽  
pp. 126-131 ◽  
Author(s):  
Milan Milosevic
Keyword(s):  
Theoretical Result ◽  
Experimental Method ◽  
Evanescent Wave ◽  
Research Topic ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Entire Field ◽  
Mental Picture ◽  
Basic Understanding ◽  
Atr Spectroscopy

This is an unusual paper in that it does not address a particular research topic or present a novel experimental method or a new theoretical result. This paper addresses our basic understanding of the nature of the evanescent wave, the wave that is the basis of the entire field of Attenuated Total Reflection (ATR) spectroscopy. I recently had the opportunity to reexamine the foundations of ATR spectroscopy and was surprised to have had to change my own mental picture of the evanescent wave that I have built over the last 25 years. Over the years I have had numerous discussions with a large number of workers in the field as well as with my former mentor, and one of the originators and the principal developer of ATR spectroscopy, the late N.J. Harrick. Everything brought up in all these discussions was perfectly consistent with my old mental picture of the evanescent wave. Thus, I believe that the picture of the evanescent wave that I had is virtually universally held by workers in the field. This paper describes the new picture of the evanescent wave that emerged from said reexamination process.

Infrared attenuated total reflection (IR-ATR) spectroscopy for detecting drugs in human saliva

2011 ◽  
Vol 4 (6) ◽  
pp. 420-429 ◽  
Author(s):  
Kerstin M.-C. Hans ◽  
Susanne Müller ◽  
Markus W. Sigrist
Keyword(s):  
Human Saliva ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Atr Spectroscopy

scholarly journals The structural stability of protein antigens adsorbed by aluminium hydroxide in comparison to the antigens in solutions

2007 ◽  
Vol 21 (5-6) ◽  
pp. 257-268 ◽  
Author(s):  
Yiwu Zheng ◽  
Xuxin Lai ◽  
Henrik Ipsen ◽  
Jørgen Nedergaard Larsen ◽  
Henning Løwenstein ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Structural Stability ◽  
Aluminium Hydroxide ◽  
Storage Temperature ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Protein Antigens ◽  
Adsorbed Protein ◽  
Vaccine Immunogenicity ◽  
Atr Spectroscopy

It is believed that antigens should be adsorbed onto adjuvants in vaccines. The adsorption-modified structure of antigens is important to understand the mechanism of adjuvants and vaccine immunogenicity. The structural stability of antigens is of major importance. The changes in structure can be induced by degradation and/or increase of storage temperature. In this study the structural stability of two model antigens, bovine serum albumin (BSA) andβ-lactoglobulin (BLG) were compared when they were adsorbed onto aluminium hydroxide and when they were in solutions using Fourier transform infrared – attenuated total reflection (FTIR-ATR) spectroscopy. The structural stability of these two proteins was studied at different temperature and during storages. The present results showed that the structure of antigens can be stabilized by adsorption onto aluminium hydroxide. Non-adsorbed protein antigens present in vaccines may facilitate the degradation of the vaccine.

scholarly journals Attenuated Total Reflection for Terahertz Modulation, Sensing, Spectroscopy and Imaging Applications: A Review

2020 ◽  
Vol 10 (14) ◽  
pp. 4688 ◽  
Author(s):  
Yuxin Huang ◽  
Ranjan Singh ◽  
Lijuan Xie ◽  
Yibin Ying
Keyword(s):  
Surface Plasmon ◽  
Analytical Methods ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Thz Spectroscopy ◽  
Wave Modulation ◽  
Thz Wave ◽  
Recent Advances ◽  
Atr Spectroscopy

Terahertz (THz) technique has become one of the most promising analytical methods and has been applied in many fields. Attenuated total reflection (ATR) technique applied in THz spectroscopy and imaging has been proven to be superior in functionalities such as modulation, sensing, analyzing, and imaging. Here, we first provide a concise introduction to the principle of ATR, discuss the factors that impact the ATR system, and demonstrate recent advances on THz wave modulation and THz surface plasmon sensing based on the THz-ATR system. Then, applications on THz-ATR spectroscopy and imaging are reviewed. Towards the later part, the advantages and limitations of THz-ATR are summarized, and prospects of modulation, surface plasmon sensing, spectroscopy and imaging are discussed.

Quantitative Determination of Prednisone in Tablets by Infrared Attenuated Total Reflection and Raman Spectroscopy

2012 ◽  
Vol 95 (3) ◽  
pp. 744-750 ◽  
Author(s):  
Sylwester Mazurek ◽  
Roman Szostak
Keyword(s):  
Predictive Ability ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Relative Standard Error ◽  
Data Sets ◽  
Spectroscopic Techniques ◽  
Validation Data ◽  
Relative Standard ◽  
Atr Spectroscopy ◽  
Ft Raman

Abstract The quantification of prednisone in tablets was performed using partial least squares (PLS) models based on FTIR-attenuated total reflection (ATR) and FT-Raman spectra. To compare the predictive ability of these models, the relative standard error of prediction (RSEP) values were calculated. In the case of prednisone determination from the FT-Raman data, RSEP values of 3.1 and 3.2% for the calibration and validation data sets were obtained. For FTIR-ATR models, which were constructed using five spectra for each sample, these errors amounted to 2.6 and 2.9%, respectively. Four commercial products containing 1, 5, 10, and 20 mg prednisone/tablet were quantified. Concentrations derived from the elaborated models correlated strongly with the results of reference analyses and with the declared values (in parentheses). The analyses gave recoveries of 100.0–101.6% (100.1–103.0%) and 98.1–103.2% (100.4–102.9%) for FTIR-ATR and FT-Raman data, respectively. A successful quantification of prednisolone in tablets containing 5 mg active ingredient/tablet was also performed using the PLS model, which was based on FTIR-ATR spectra, with a recovery of 99.8 (98.8%). Both reported spectroscopic techniques can be used as fast and convenient alternatives to the standard pharmacopeial methods of prednisone and prednisolone quantification in solid dosage forms. However, in the case of FTIR-ATR spectroscopy, it is necessary to repeat measurements several times to obtain sufficiently low quantification errors.

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