TY - JOUR A1 - Carvalho, Thayslan A1 - Brosinsky, Arlena A1 - Foerster, Saskia A1 - Teixeira, Adunias A1 - Medeiros, Pedro Henrique Augusto T1 - Reservoir sediment characterisation by diffuse reflectance spectroscopy in a semiarid region to support sediment reuse for soil fertilization JF - Journal of soils and sediments : protection, risk assessment and remediation N2 - Purpose: Soil erosion by water yields sediment to surface reservoirs, reducing their storage capacities, changing their geometry, and degrading water quality. Sediment reuse, i.e., fertilization of agricultural soils with the nutrient-enriched sediment from reservoirs, has been proposed as a recovery strategy. However, the sediment needs to meet certain criteria. In this study, we characterize sediments from the densely dammed semiarid Northeast Brazil by VNIR-SWIR spectroscopy and assess the effect of spectral resolution and spatial scale on the accuracy of N, P, K, C, electrical conductivity, and clay prediction models. Methods Sediment was collected in 10 empty reservoirs, and physical and chemical laboratory analyses as well as spectral measurements were performed. The spectra, initially measured at 1 nm spectral resolution, were resampled to 5 and 10 nm, and samples were analysed for both high and low spectral resolution at three spatial scales, namely (1) reservoir, (2) catchment, and (3) regional scale. Results Partial least square regressions performed from good to very good in the prediction of clay and electrical conductivity from reservoir (<40 km(2)) to regional (82,500 km(2)) scales. Models for C and N performed satisfactorily at the reservoir scale, but degraded to unsatisfactory at the other scales. Models for P and K were more unstable and performed from unsatisfactorily to satisfactorily at all scales. Coarsening spectral resolution by up to 10 nm only slightly degrades the models' performance, indicating the potential of characterizing sediment from spectral data captured at lower resolutions, such as by hyperspectral satellite sensors. Conclusion: By reducing the costly and time-consuming laboratory analyses, the method helps to promote the sediment reuse as a practice of soil and water conservation. KW - Sediment characterization KW - Spectroscopy KW - Sediment reuse KW - Surface KW - reservoirs KW - Semiarid KW - Brazil Y1 - 2022 U6 - https://doi.org/10.1007/s11368-022-03281-1 SN - 1439-0108 SN - 1614-7480 VL - 22 SP - 2557 EP - 2577 PB - Springer CY - Heidelberg ER - TY - JOUR A1 - Picconi, David T1 - Nonadiabatic quantum dynamics of the coherent excited state intramolecular proton transfer of 10-hydroxybenzo[h]quinoline JF - Photochemical & photobiological sciences N2 - The photoinduced nonadiabatic dynamics of the enol-keto isomerization of 10-hydroxybenzo[h]quinoline (HBQ) are studied computationally using high-dimensional quantum dynamics. The simulations are based on a diabatic vibronic coupling Hamiltonian, which includes the two lowest pi pi* excited states and a n pi* state, which has high energy in the Franck-Condon zone, but significantly stabilizes upon excited state intramolecular proton transfer. A procedure, applicable to large classes of excited state proton transfer reactions, is presented to parametrize this model using potential energies, forces and force constants, which, in this case, are obtained by time-dependent density functional theory. The wave packet calculations predict a time scale of 10-15 fs for the photoreaction, and reproduce the time constants and the coherent oscillations observed in time- resolved spectroscopic studies performed on HBQ. In contrast to the interpretation given to the most recent experiments, it is found that the reaction initiated by 1 pi pi* <- S-0 photoexcitation proceeds essentially on a single potential energy surface, and the observed coherences bear signatures of Duschinsky mode-mixing along the reaction path. The dynamics after the 2 pi pi* <- S-0 excitation are instead nonadiabatic, and the n pi* state plays a major role in the relaxation process. The simulations suggest a mainly active role of the proton in the isomerization, rather than a passive migration assisted by the vibrations of the benzoquinoline backbone.
[GRAPHICS]
. KW - Excited state proton transfer KW - Quantum dynamics KW - Nonadiabatic effects KW - Spectroscopy KW - Coherences Y1 - 2021 U6 - https://doi.org/10.1007/s43630-021-00112-z SN - 1474-905X SN - 1474-9092 VL - 20 IS - 11 SP - 1455 EP - 1473 PB - Springer CY - Heidelberg ER - TY - JOUR A1 - Rousseau, Batiste A1 - Erard, Stéphane A1 - Beck, P. A1 - Quirico, Eric A1 - Schmitt, B. A1 - Brissaud, O. A1 - Montes-Hernandez, G. A1 - Capaccioni, F. A1 - Filacchione, Gianrico A1 - Bockelee-Morvan, Dominique A1 - Leyrat, C. A1 - Ciarniello, M. A1 - Raponi, Andrea A1 - Kappel, David A1 - Arnold, G. A1 - Moroz, L. V. A1 - Palomba, Ernesto A1 - Tosi, Federico T1 - Laboratory simulations of the Vis-NIR spectra of comet 67P using sub-mu m sized cosmochemical analogues JF - Icarus : international journal of solar system studies N2 - Laboratory spectral measurements of relevant analogue materials were performed in the framework of the Rosetta mission in order to explain the surface spectral properties of comet 67P. Fine powders of coal, iron sulphides, silicates and their mixtures were prepared and their spectra measured in the Vis-IR range. These spectra are compared to a reference spectrum of 67P nucleus obtained with the VIRTIS/Rosetta instrument up to 2.7 mu m, excluding the organics band centred at 3.2 mu m. The species used are known to be chemical analogues for cometary materials which could be present at the surface of 67P. Grain sizes of the powders range from tens of nanometres to hundreds of micrometres. Some of the mixtures studied here actually reach the very low reflectance level observed by VIRTIS on 67P. The best match is provided by a mixture of sub-micron coal, pyrrhotite, and silicates. Grain sizes are in agreement with the sizes of the dust particles detected by the GIADA, MIDAS and COSIMA instruments on board Rosetta. The coal used in the experiment is responsible for the spectral slope in the visible and infrared ranges. Pyrrhotite, which is strongly absorbing, is responsible for the low albedo observed in the NIR. The darkest components dominate the spectra, especially within intimate mixtures. Depending on sample preparation, pyrrhotite can coat the coal and silicate aggregates. Such coating effects can affect the spectra as much as particle size. In contrast, silicates seem to play a minor role. (c) 2017 Elsevier Inc. All rights reserved. KW - Comets KW - Comets nucleus KW - Comets composition KW - Spectroscopy KW - Experimental techniques Y1 - 2018 U6 - https://doi.org/10.1016/j.icarus.2017.10.015 SN - 0019-1035 SN - 1090-2643 VL - 306 SP - 306 EP - 318 PB - Elsevier CY - San Diego ER - TY - JOUR A1 - Zehbe, Rolf A1 - Zehbe, Kerstin T1 - Strontium doped poly-epsilon-caprolactone composite scaffolds made by reactive foaming JF - The European journal of the history of economic thought N2 - In the reconstruction and regeneration of bone tissue, a primary goal is to initiate bone growth and to stabilize the surrounding bone. In this regard, a potentially useful component in biomaterials for bone tissue engineering is strontium, which acts as cationic active agent, triggering certain intracellular pathways and acting as so called dual action bone agent which inhibits bone resorption while stimulating bone regeneration. In this study we established a novel processing for the foaming of a polymer (poly-epsilon-caprolactone) and simultaneous chemical reaction of a mixture of calcium and strontium hydroxides to the respective carbonates using supercritical carbon dioxide. The resultant porous composite scaffold was optimized in composition and strontium content and was characterized via different spectroscopic (infrared and Raman spectroscopy, energy dispersive X-ray spectroscopy), imaging (SEM, mu CT), mechanical testing and in vitro methods (fluorescence vital staining, MTT-assay). As a result, the composite scaffold showed good in vitro biocompatibility with partly open pore structure and the expected chemistry. First mechanical testing results indicate sufficient mechanical stability to support future in vivo applications. (C) 2016 Elsevier B.V. All rights reserved. KW - Strontium KW - Poly-epsilon-caprolactone KW - Porous scaffold KW - CAL-72 osteoblasts KW - L-929 fibroblasts KW - Reactive foaming KW - mu CT imaging KW - Spectroscopy Y1 - 2016 U6 - https://doi.org/10.1016/j.msec.2016.05.045 SN - 0928-4931 SN - 1873-0191 VL - 67 SP - 259 EP - 266 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Brosinsky, Arlena A1 - Förster, Saskia A1 - Segl, Karl A1 - Lopez-Tarazon, José Andrés A1 - Pique, Gemma A1 - Bronstert, Axel T1 - Spectral fingerprinting: characterizing suspended sediment sources by the use of VNIR-SWIR spectral information JF - Journal of soils and sediments : protection, risk assessment and remediation N2 - Knowledge of sediment sources is a prerequisite for sustainable management practices and may furthermore improve our understanding of water and sediment fluxes. Investigations have shown that a number of characteristic soil properties can be used as "fingerprints" to trace back the sources of river sediments. Spectral properties have recently been successfully used as such characteristics in fingerprinting studies. Despite being less labour-intensive than geochemical analyses, for example, spectroscopy allows measurements of small amounts of sediment material (> 60 mg), thus enabling inexpensive analyses even of intra-event variability. The focus of this study is on the examination of spectral properties of fluvial sediment samples to detect changes in source contributions, both between and within individual flood events. Sediment samples from the following three different origins were collected in the Isabena catchment (445 km(2)) in the central Spanish Pyrenees: (1) soil samples from the main potential source areas, (2) stored fine sediment from the channel bed once each season in 2011 and (3) suspended sediment samples during four flood events in autumn 2011 and spring 2012 at the catchment outlet as well as at several subcatchment outlets. All samples were dried and measured for spectral properties in the laboratory using an ASD spectroradiometer. Colour parameters and physically based features (e.g. organic carbon, iron oxide and clay content) were calculated from the spectra. Principal component analyses (PCA) were applied to all three types of samples to determine natural clustering of samples, and a mixing model was applied to determine source contributions. We found that fine sediment stored in the river bed seems to be mainly influenced by grain size and seasonal variability, while sampling location-and thus the effect of individual tributaries or subcatchments-seem to be of minor importance. Suspended sediment sources were found to vary between, as well as within, flood events; although badlands were always the major source. Forests and grasslands contributed little (< 10 %), and other sources (not further determinable) contributed up to 40 %. The analyses further suggested that sediment sources differ among the subcatchments and that subcatchments comprising relatively large proportions of badlands contributed most to the four flood events analyzed. Spectral fingerprints provide a rapid and cost-efficient alternative to conventional fingerprint properties. However, a combination of spectral and conventional fingerprint properties could potentially permit discrimination of a larger number of source types. KW - Isabena river KW - Mixing models KW - Northeast Spain KW - Sediment fingerprinting KW - Spectroscopy KW - Suspended sediment Y1 - 2014 U6 - https://doi.org/10.1007/s11368-014-0927-z SN - 1439-0108 SN - 1614-7480 VL - 14 IS - 12 SP - 1965 EP - 1981 PB - Springer CY - Heidelberg ER - TY - JOUR A1 - Brosinsky, Arlena A1 - Förster, Saskia A1 - Segl, Karl A1 - Kaufmann, Hermann T1 - Spectral fingerprinting: sediment source discrimination and contribution modelling of artificial mixtures based on VNIR-SWIR spectral properties JF - Journal of soils and sediments : protection, risk assessment and remediation N2 - Knowledge of the origin of suspended sediment is important for improving our understanding of sediment dynamics and thereupon support of sustainable watershed management. An direct approach to trace the origin of sediments is the fingerprinting technique. It is based on the assumption that potential sediment sources can be discriminated and that the contribution of these sources to the sediment can be determined on the basis of distinctive characteristics (fingerprints). Recent studies indicate that visible-near-infrared (VNIR) and shortwave-infrared (SWIR) reflectance characteristics of soil may be a rapid, inexpensive alternative to traditional fingerprint properties (e.g. geochemistry or mineral magnetism). To further explore the applicability of VNIR-SWIR spectral data for sediment tracing purposes, source samples were collected in the Isabena watershed, a 445 km(2) dryland catchment in the central Spanish Pyrenees. Grab samples of the upper soil layer were collected from the main potential sediment source types along with in situ reflectance spectra. Samples were dried and sieved, and artificial mixtures of known proportions were produced for algorithm validation. Then, spectral readings of potential source and artificial mixture samples were taken in the laboratory. Colour coefficients and physically based parameters were calculated from in situ and laboratory-measured spectra. All parameters passing a number of prerequisite tests were subsequently applied in discriminant function analysis for source discrimination and mixing model analyses for source contribution assessment. The three source types (i.e. badlands, forest/grassland and an aggregation of other sources, including agricultural land, shrubland, unpaved roads and open slopes) could be reliably identified based on spectral parameters. Laboratory-measured spectral fingerprints permitted the quantification of source contribution to artificial mixtures, and introduction of source heterogeneity into the mixing model decreased accuracies for some source types. Aggregation of source types that could not be discriminated did not improve mixing model results. Despite providing similar discrimination accuracies as laboratory source parameters, in situ derived source information was found to be insufficient for contribution modelling. The laboratory mixture experiment provides valuable insights into the capabilities and limitations of spectral fingerprint properties. From this study, we conclude that combinations of spectral properties can be used for mixing model analyses of a restricted number of source groups, whereas more straightforward in situ measured source parameters do not seem suitable. However, modelling results based on laboratory parameters also need to be interpreted with care and should not rely on the estimates of mean values only but should consider uncertainty intervals as well. KW - Artificial mixture KW - Mixing model KW - Sediment fingerprinting KW - Spectroscopy Y1 - 2014 U6 - https://doi.org/10.1007/s11368-014-0925-1 SN - 1439-0108 SN - 1614-7480 VL - 14 IS - 12 SP - 1949 EP - 1964 PB - Springer CY - Heidelberg ER - TY - JOUR A1 - Zude, Manuela A1 - Pflanz, Michael A1 - Spinelli, Lorenzo A1 - Dosche, Carsten A1 - Torricelli, Alessandro T1 - Non-destructive analysis of anthocyanins in cherries by means of Lambert-Beer and multivariate regression based on spectroscopy and scatter correction using time-resolved analysis JF - Journal of food engineering N2 - In high-value sweet cherry (Prunus avium), the red coloration - determined by the anthocyanins content - is correlated with the fruit ripeness stage and market value. Non-destructive spectroscopy has been introduced in practice and may be utilized as a tool to assess the fruit pigments in the supply chain processes. From the fruit spectrum in the visible (Vis) wavelength range, the pigment contents are analyzed separately at their specific absorbance wavelengths. A drawback of the method is the need for re-calibration due to varying optical properties of the fruit tissue. In order to correct for the scattering differences, most often the spectral intensity in the visible spectrum is normalized by wavelengths in the near infrared (NIR) range, or pre-processing methods are applied in multivariate calibrations. In the present study, the influence of the fruit scattering properties on the Vis/NIR fruit spectrum were corrected by the effective pathlength in the fruit tissue obtained from time-resolved readings of the distribution of time-of-flight (DTOF). Pigment analysis was carried out according to Lambert-Beer law, considering fruit spectral intensities, effective pathlength, and refractive index. Results were compared to commonly applied linear color and multivariate partial least squares (PLS) regression analysis. The approaches were validated on fruits at different ripeness stages, providing variation in the scattering coefficient and refractive index exceeding the calibration sample set. In the validation, the measuring uncertainty of non-destructively analyzing fruits with Vis/NIR spectra by means of PLS or Lambert-Beer in comparison with combined application of Vis/NIR spectroscopy and DTOF measurements showed a dramatic bias reduction as well as enhanced coefficients of determination when using both, the spectral intensities and apparent information on the scattering influence by means of DTOF readings. Corrections for the refractive index did not render improved results. KW - Cherry KW - DTOF KW - Effective pathlength KW - Fruit maturity KW - Lambert-Beer KW - NIR KW - Non-invasive KW - Pigments KW - PLS KW - Ripeness KW - Sensor fusion KW - Spectroscopy KW - Time-resolved spectroscopy KW - TIRF KW - Vis KW - Scattering Y1 - 2011 U6 - https://doi.org/10.1016/j.jfoodeng.2010.09.021 SN - 0260-8774 VL - 103 IS - 1 SP - 68 EP - 75 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - de Vera, Jean-Pierre Paul A1 - Böttger, Ute A1 - de la Torre Nötzel, Rosa A1 - Sanchez, Francisco J. A1 - Grunow, Dana A1 - Schmitz, Nicole A1 - Lange, Caroline A1 - Hübers, Heinz-Wilhelm A1 - Billi, Daniela A1 - Baque, Mickael A1 - Rettberg, Petra A1 - Rabbow, Elke A1 - Reitz, Günther A1 - Berger, Thomas A1 - Möller, Ralf A1 - Bohmeier, Maria A1 - Horneck, Gerda A1 - Westall, Frances A1 - Jänchen, Jochen A1 - Fritz, Jörg A1 - Meyer, Cornelia A1 - Onofri, Silvano A1 - Selbmann, Laura A1 - Zucconi, Laura A1 - Kozyrovska, Natalia A1 - Leya, Thomas A1 - Foing, Bernard A1 - Demets, Rene A1 - Cockell, Charles S. A1 - Bryce, Casey A1 - Wagner, Dirk A1 - Serrano, Paloma A1 - Edwards, Howell G. M. A1 - Joshi, Jasmin Radha A1 - Huwe, Björn A1 - Ehrenfreund, Pascale A1 - Elsaesser, Andreas A1 - Ott, Sieglinde A1 - Meessen, Joachim A1 - Feyh, Nina A1 - Szewzyk, Ulrich A1 - Jaumann, Ralf A1 - Spohn, Tilman T1 - Supporting Mars exploration BIOMEX in Low Earth Orbit and further astrobiological studies on the Moon using Raman and PanCam technology JF - Planetary and space science N2 - The Low Earth Orbit (LEO) experiment Biology and Mars Experiment (BIOMEX) is an interdisciplinary and international space research project selected by ESA. The experiment will be accommodated on the space exposure facility EXPOSE-R2 on the International Space Station (ISS) and is foreseen to be launched in 2013. The prime objective of BIOMEX is to measure to what extent biomolecules, such as pigments and cellular components, are resistant to and able to maintain their stability under space and Mars-like conditions. The results of BIOMEX will be relevant for space proven biosignature definition and for building a biosignature data base (e.g. the proposed creation of an international Raman library). The library will be highly relevant for future space missions such as the search for life on Mars. The secondary scientific objective is to analyze to what extent terrestrial extremophiles are able to survive in space and to determine which interactions between biological samples and selected minerals (including terrestrial, Moon- and Mars analogs) can be observed under space and Mars-like conditions. In this context, the Moon will be an additional platform for performing similar experiments with negligible magnetic shielding and higher solar and galactic irradiation compared to LEO. Using the Moon as an additional astrobiological exposure platform to complement ongoing astrobiological LEO investigations could thus enhance the chances of detecting organic traces of life on Mars. We present a lunar lander mission with two related objectives: a lunar lander equipped with Raman and PanCam instruments which can analyze the lunar surface and survey an astrobiological exposure platform. This dual use of testing mission technology together with geo- and astrobiological analyses will significantly increase the science return, and support the human preparation objectives. It will provide knowledge about the Moon's surface itself and, in addition, monitor the stability of life-markers, such as cells, cell components and pigments, in an extraterrestrial environment with much closer radiation properties to the surface of Mars. The combination of a Raman data base of these data together with data from LEO and space simulation experiments, will lead to further progress on the analysis and interpretation of data that we will obtain from future Moon and Mars exploration missions. KW - Moon KW - Mars KW - Low Earth Orbit KW - Astrobiology KW - Instrumentation KW - Spectroscopy KW - Biosignature Y1 - 2012 U6 - https://doi.org/10.1016/j.pss.2012.06.010 SN - 0032-0633 VL - 74 IS - 1 SP - 103 EP - 110 PB - Elsevier CY - Oxford ER -