A method for the automated Raman spectra acquisition.

Raman spectroscopy is a very powerful analytical technique with an increasing acceptance in the scientific community. For theoptimization of the Raman acquisition, two main parameters, the integration time and the number of accumulations, need tobe adjusted to the sample under analysis, as the sample, or even different spots on the same sample, can provide very differentRaman responses one from another. In this paper, we present a suite of algorithms to automate the acquisition parameteradjustment to the sample under analysis, addressing issues such as spectral saturation, fluorescence, cosmic ray detection andremoval, and adjustment of the acquisition parameters to optimize the acquired spectral data. This suite has been developedin the framework of the Raman Laser Spectrometer (RLS) instrument development for the Exomars mission but can be appliedto any Raman spectrometer. This will allow the spectrometer to adapt to the characteristics of the sample that is being analyzed,optimizing the total operative time, while improving the usability and overall efficiency of the system. Copyright © 2017 JohnWiley & Sons, Ltd.MINECO ESP2014-56138-C3-1-

A Rich Morphological Diversity of Biosaline Drying Patterns Is Generated by Different Bacterial Species, Different Salts and Concentrations: Astrobiological Implications

Biosaline formations (BSFs) are complex self-organized biomineral patterns formed by ‘‘hibernating’’ bacteria as the biofilm that contains them dries out. They were initially described in drying biofilms of Escherichia coli cells + NaCl. Due to their intricate 3-D morphology and anhydrobiosis, these biomineralogical structures are of great interest in astrobiology. Here we report experimental data obtained with various alkali halide salts (NaF, NaCl, NaBr, LiCl, KCl, CsCl) on BSF formation with E. coli and Bacillus subtilis bacteria at two saline concentrations: 9 and 18 mg/mL. Our results indicate that, except for LiCl, which is inactive, all the salts assayed are active during BSF formation and capable of promoting the generation of distinctive drying patterns at each salt concentration. Remarkably, the BSFs produced by these two bacterial species produce characteristic architectural hallmarks as the BSF dries. The potential biogenicity of these biosaline drying patterns is studied, and the astrobiological implications of these findings are discusse

Combined vibrational, structural, elemental and Mössbauer spectroscopic analysis of natural phillipsite (zeolite) from historical eruptions in Tenerife, Canary Islands: Implication for Mars

The outcrop of “Las Arenas” volcano in Tenerife, Canary Islands (Spain) has been presented as Terrestrial volcanic analog for ancient Mars, showing a great variety of alteration processes and interesting mineralogy. The current analysis has been done by means of measurement techniques used or proposed on Martian studies. The new analysis of the zeolite has been carried out using Raman spectroscopy, Mössbauer spectroscopy, X-ray diffraction (XRD), Infrared spectroscopy, Laser induced breakdown spectroscopy and Scanning electron microscopy (SEM-EDX). The zeolite has been carefully analyzed using vibrational spectroscopy and it has been identified as Ca-phillipsite. The other techniques support and confirm the results. The measurements and results using the Raman Laser Spectrometer (RLS) simulator system show the capabilities RLS system in the ESA Exo- Mars mission. The chemometrical methods for the vibrational mineral detection show the advantages of Raman spectroscopy to understand the possible geological context. Furthermore, the proposed diagenesis and formation of the zeolites in southern part of Tenerife island have been confirmed by the twin space prototypes used. A new hypothesis about the origin for the special case of “Las Arenas” volcano Ca-phillipsite has been proposed. Finally, a multi-complementary comparison among the different techniques used on the current studie has been done and, also an analogy with the next space mission has been established. These analyses emphasize the strength of the different techniques and the working synergy of the different techniques together for planetary space missions

Amorphous zinc borate as a simple standard for baseline correction in Raman spectra

In this paper, our research group proposes a simple solution to a usual problem that appears in the Raman analysis of some substances, which is the presence of weak Raman signals, probably in combination with a high‐intensity luminescence background, affected by the presence of distortions in the baseline. Under this condition, the spectroscopist has to face spectra hard to edit and correct and thus hard to study. There are already some standard solutions that allow the correction of spectra from relative intensity to absolute intensity that also solves this problem and also allow quantitative analyses. But these solutions imply expensive standards or devices that could not be a worthy option when not working in absolute intensity or the Raman analyses stay at qualitative level and a quantitative study is not needed. The alternative Do It Yourself solution proposed in this paper is based on the use of amorphous zinc borate, an easy‐to‐find substance, which after a simple processing allows us to correct the baseline of Raman spectra qualitatively, offering a useful and economic reference when an absolute intensity correction is not needed. In order to evaluate the effectiveness of this procedure, some spectra were corrected using amorphous zinc borate and then compared the signal‐to‐noise ratio of some Raman signals before and after this correction. Copyright © 2017 John Wiley & Sons, Ltd.MINECO ESP2014-56138-C3-1-

In situ Raman characterization of minerals and degradation processes in a variety of cultural and geological heritage sites

Wetest the capabilities of in situ Raman spectroscopy for non-destructive analysis of degradation processes in invaluable masterpieces, as well as for the characterization of minerals and prehistoric rock-art in caves. To this end, we have studied the mechanism of decay suffered by the 15th-century limestone sculptures that decorate the retro-choir of Burgos Cathedral (N Spain). In situ Raman probe detected hydrated sulfate and nitrateminerals on the sculptures, which are responsible for the decay of the original limestone. In addition, in situ Raman analyses were performed on unique speleothems in El Soplao Cave (Cantabria, N Spain) and in the Gruta de las Maravillas (Aracena, SWSpain). Unusual cavemineralswere detected in El Soplao Cave, such as hydromagnesite (Mg5(CO3)4(OH)2·4H2O), as well as ferromanganese oxides in the black biogenic speleothems recently discovered in this cavern. In the Gruta de las Maravillas, gypsum (CaSO4·2H2O) was identified for the first time, as part of the oldest cave materials, so providing additional evidence of hypogenic mechanisms that occurred in this cave during earlier stages of its formation. Finally, we present preliminary analyses of several cave paintings in the renowned “Polychrome Hall” of Altamira Cave (Cantabria, N. Spain). Hematite (Fe2O3) is the most abundant mineral phase, which provides the characteristic ochre-reddish color to the Altamira bison and deer paintings. Thus, portable Raman spectroscopy is demonstrated to be an analytical technique compatible with preserving our cultural and natural heritage, since the analysis does not require physical contact between the Raman head and the analyzed items

Surface and microstructural failures of PET-Coated ECCS plates by salmon-polymer interaction

Producción CientíficaThe new types of knowledge-intensive, multilayer containers consist of steel plates protected against corrosion by nanometric electrolytic chromium (Cr0) and chromium oxide (Cr2O3) layers chemically bonded to polyethylene terephthalate (PET) polymer coating to preserve food. It was observed that after emptying the cans, the salmon adhered to the polymer coating, changing its color, and that this adhesion increased with longer storage times. This work was aimed at determining the product-container interactions and their characterization by X-ray diffraction (XRD), confocal Raman and micro-Raman imaging and scanning electron microscopy (SEM) analysis. The zones of adhesion showed surface changes, variations in crystallinity and microstructural degradation of the PET coating. In addition, localized damages altering the functional properties of the multilayer system were observed as microcracking in the chromium layers that protect the steel. The degradation undergone was evaluated and characterized at a surface and microstructural level to establish the failure mechanisms, which were mainly associated with the activity of the adhered muscle and its biochemical components. Finally, a recommendation is done to preserve the useful life and functionality of cans for the preservation and efficient use of resources with an impact on recycling and environmental conservancy.The authors gratefully acknowledge the Fondecyt Program of Conicyt Chile for the financial support through Grant No. 1130634 and the special contribution of University Austral of Chile

Survival of Moss Reproductive Structures under Simulated Martian Environmental Conditions and Extreme Thermal Stress: Vibrational Spectroscopic Study and Astrobiological Implications

The principal goal of astrobiology is the search for extraterrestrial life forms. A key aspect is the study of the ability of different kinds of terrestrial organisms to support simulated extraterrestrial environmental conditions. Mosses are multicellular green plants, poorly studied from an astrobiological perspective. In this paper, we report experimental results obtained using two species of moss, which demonstrate that both the spores of the moss Funaria hygrometrica as well as the desiccated vegetative gametophyte shoots of the moss Tortella squarrosa (=Pleurochaete squarrosa) were capable of resisting Simulated Martian Environmental Conditions (SMEC): Mars simulated atmospheric composition 99.9% CO2, and 0.6% H2O with a pressure of 7 mbars, -73 ºC and UV irradiation of 30 mW cm-2 in a wavelength range of 200-400 nm under a limited short time of exposition of 2 hours. After being exposed to SMEC and then transferred to an appropriate growth medium, the F. hygrometrica spores germinated, producing typical gametophyte protonemal cells and leafy shoots. Likewise, detached leaves from SMEC-exposed gametophyte shoots of T. squarrosa retained the ability to produce new protonemata and shoots under suitable growth conditions. Furthermore, we studied the tolerance of these moss structures to a thermal stress of 100 °C for 1 h; in both cases the spores and shoots were capable of resisting this heat treatment. Our study using FT-Raman and FT-IR vibrational spectroscopy demonstrated that neither spores nor shoots apparently suffered significant damage in their biomolecular makeup after being subject to these stress treatments. The implications of these findings for the search of life on Mars are discussed

Nd3+-doped TeO2–PbF2–AlF3 glasses for laser applications

A study of the optical properties of Nd3+ ion in TeO2–PbF2–AlF3 glasses has been carried out for different Nd3+ concentrations. Based on the Judd–Ofelt theory, intensity parameters and radiative properties were determined from the absorption spectra. Focusing on the suitability of this host for laser applications, the spectroscopic quality factor v was obtained with a value of 1.07, a value of the order of other compositions proposed as laser hosts. For the most intense emission corresponding with the 4F3/2?4I11/2 transition (1.06 lm), the absorption and emission and have been calculated with values of 1.20 10 20 cm2, 2.08 10 20 cm2. A positive value for the gain cross-sections has been found for a population inversion factor c of 0.4 in the spectral range from 1060 to 1110 nm. All these results suggest the potentially use of this system as a laser host

Estudio de basaltos mediante espectroscopía de plasma inducido por láser (LIBS) para la fabricación de bloques de lapilli

Se analizaron mediante espectroscopía de plasma inducido por láser (LIBS), espectroscopía Raman y difracción de rayos x (XRD) muestras seleccionadas de diversas zonas de Tenerife, con el objetivo de identificar su composición química elemental y mineralógica. Los resultados mostraron los elementos mayoritarios siguientes: O, F, Na, K, Mg, Al, Si, Ca, Ti y Fe. La identificación de las muestras, mediante espectroscopía Raman y XRD, mostró una mineralogía de tipo basáltica coincidente con los resultados de composición elemental LIBS. Los resultados de los análisis con instrumentación portátil demuestran la aplicabilidad de la espectroscopía LIBS y, en especial, en combinación con la espectroscopía Raman, para su utilización en la detección mineralógica-química en las zonas de extracción de basaltos y picón para la construcción en Tenerife

Habitability on Early Mars and the Search for Biosignatures with the ExoMars Rover

The second ExoMars mission will be launched in 2020 to target an ancient location interpreted to have strong potential for past habitability and for preserving physical and chemical biosignatures (as well as abiotic/prebiotic organics). The mission will deliver a lander with instruments for atmospheric and geophysical investigations and a rover tasked with searching for signs of extinct life. The ExoMars rover will be equipped with a drill to collect material from outcrops and at depth down to 2 m. This subsurface sampling capability will provide the best chance yet to gain access to chemical biosignatures. Using the powerful Pasteur payload instruments, the ExoMars science team will conduct a holistic search for traces of life and seek corroborating geological context information. Key Words: Biosignatures—ExoMars—Landing sites—Mars rover—Search for life. Astrobiology 17, 471–510