Field-Based Raman Spectroscopic Analyses of an Ordovician Stromatolite

Astrobiology ◽  
2013 ◽  
Vol 13 (9) ◽  
pp. 814-820 ◽  
Author(s):  
Alison Olcott Marshall ◽  
Craig P. Marshall
Keyword(s):  
Raman Spectroscopic ◽  
Spectroscopic Analyses

Raman spectroscopic study of the photoprotection of extremophilic microbes against ultraviolet radiation

2006 ◽  
Vol 5 (4) ◽  
pp. 313-318 ◽  
Author(s):  
H.G.M. Edwards ◽  
R. Moeller ◽  
S.E. Jorge Villar ◽  
G. Horneck ◽  
E. Stackebrandt
Keyword(s):  
Deinococcus Radiodurans ◽  
Survival Strategies ◽  
Raman Spectroscopic ◽  
Spectroscopic Analyses ◽  
Terrestrial Habitats ◽  
Life Context ◽  
Wavelength Radiation ◽  
Spectroscopic Instrumentation ◽  
Natronomonas Pharaonis ◽  
Uva Radiation

Extremophiles use a range of pigments for protection against low-wavelength radiation in exposed terrestrial habitats and photoaccessory materials are synthesized for the effective harnessing of photosynthetically active radiation. Raman spectroscopy has been demonstrated to be a useful probe for information on the survival strategies employed by extremophilic bacteria through the identification of key biomolecular signatures of the suite of protective chemicals synthesized by the organisms in stressed environments. Raman spectroscopic analyses of Bacillus spp. spores, Bacillus atrophaeus (DSM 675: deep red) and Bacillus subtilis (DSM 5611: light grey and DSM 7264: dark grey), Deinococcus radiodurans (pink) and Natronomonas pharaonis (red), of visually different pigmentation showed the presence of different carotenoids and other protectant biomolecules, which assist microorganisms against UVA radiation. The implications for the survival of extremophilic microbes in extraterrestrial habitats and for the detection of the protectant biomolecules by remote, robotic Raman spectroscopic instrumentation in an astrobiological search for life context are discussed.

scholarly journals Characterization of Two Historical Postage Stamps Made from Cotton Fibers and Their Restoration Trials Based on the Experimental Studies

2021 ◽  
Vol 2021 ◽  
pp. 1-21
Author(s):  
Maisa M.A. Mansour ◽  
Yassin E. Zidan ◽  
Abou El Fettouh A Abd El Hakim ◽  
Mohamed Mahmoud Allam ◽  
Hayssam M. Ali ◽  
...  
Keyword(s):  
Color Change ◽  
Linseed Oil ◽  
Experimental Studies ◽  
Gum Arabic ◽  
Oxidation Reactions ◽  
Raman Spectroscopic ◽  
Ultramarine Blue ◽  
Spectroscopic Analyses ◽  
Postage Stamps ◽  
Printing Inks

Ancient stamps are suffering from the destructive effects of different kinds of inks that were prepared from different ingredients. Two Egyptian historical postage stamps printed in blue and red printing inks were evaluated and examined for their composition using a light microscope, SEM-EDS, FTIR, and Raman spectroscopic analyses. Mechanical, chemical, and deacidification treatments were done for the two stamps. Model stamps were made from the cotton pulp in the book house to simulate historical stamp paper with an average thickness of 11 microns. The unprinted and printed paper samples with printing inks that aged and unaged were treated with 0.7% Klucel G, 0.2% TiO2 NP, or a mixture of 0.7% Klucel G + 0.2% TiO2 NP, and the color change was measured and compared with the blank samples. The two stamps are suffering from high pH, where the margin color of the stamps changed to yellow-brown with weakness of the stamp paper. By SEM examination, stamps have suffered from fibers’ weakness and dryness resulting from the self-oxidation reactions. EDS elemental composition of the red stamp showed the presence of C, O, Na, Al, Si, Mg, S, Ca, Ba, and Fe, while in the blue stamp, it was C, O, Na, Al, Si, P, S, Cl, and Ca. Raman spectrometer wavelengths turn out that the blueprinting ink of the stamp was characterized with spectra of ultramarine blue (lazurite), while hematite was characterized by the red stamp. FTIR analysis for the printing inks identified that gum Arabic sample and linseed oil were the binding and color medium, respectively. From the model trials, it was observed that the treatment of a mixture of Klucel G and TiO2 NP had the best properties for the consolidation of stamps. The two historical stamps were documented through different spectroscopic analyses, and from the restoration trials, it was observed that the mixture of 7% Klucel G + 0.2% TiO2 NP appeared to be a new and effective method for recovering the historical postage stamps.

Continuing Etching of an All-in-One Adhesive in Wet Dentin Tubules

2005 ◽  
Vol 84 (4) ◽  
pp. 350-354 ◽  
Author(s):  
Y. Wang ◽  
P. Spencer
Keyword(s):  
Spectroscopic Analysis ◽  
Monomer Conversion ◽  
Third Molars ◽  
Electron Microscopic ◽  
Raman Spectroscopic ◽  
Spectroscopic Analyses ◽  
Adhesive Penetration ◽  
Scanning Electron Microscopic ◽  
Self Etch ◽  
Raman Spectroscopic Analysis

Self-etch adhesives that etch and prime simultaneously are becoming more acidic. We hypothesized that the degree of acidic monomer conversion at the interface and within the tubules was high enough that the acidic reaction would be very self-limiting. Dentin surfaces prepared from extracted, unerupted human third molars were treated with Prompt L-Pop (3M ESPE). The prepared teeth were stored in normal saline, and specimens retrieved at intervals ≤ 4 wks were randomly selected for light, scanning electron microscopic and micro-Raman spectroscopic analysis. Morphologic and spectroscopic analyses indicated dentin demineralization and adhesive penetration throughout the demineralized layer and tubules. Increased dentin demineralization and loss of adhesive integrity were noted after aqueous storage. The degree of monomer conversion at the interface was consistently greater than conversion within the tubules. Fluid within the tubules may inhibit monomer conversion. The acidic characteristics of this adhesive may be retained and, thus, continue to affect/demineralize the surrounding dentin.

Structural study of amorphous WO3 thin films prepared by the ion exchange method

1991 ◽  
Vol 6 (6) ◽  
pp. 1324-1333 ◽  
Author(s):  
Tokuro Nanba ◽  
Yoshio Nishiyama ◽  
Itaru Yasui
Keyword(s):  
Ion Exchange ◽  
Sodium Tungstate ◽  
Exchange Method ◽  
Raman Spectroscopic ◽  
Spectroscopic Analyses ◽  
Edge Sharing Octahedra ◽  
Ir And Raman ◽  
Wo3 Thin Films ◽  
Low Symmetry ◽  
Xrd Method

The structure of amorphous tungsten trioxide films was investigated with IR and Raman spectroscopic analyses and an XRD method. The films were prepared by ion exchange from sodium tungstate as a starting material. Films consisted of microclusters of 10–30 Å diameter, in which the networks are formed with WO6 octahedra sharing their corners and edges. The networks in the as-prepared samples consisted of WO6 units with low symmetry, in which termination by W=O and W—OH2 groups was common. As the post-annealed temperature became higher, the symmetry of WO6 was improved and the edge-sharing octahedra disappeared.

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