Multianalytical characterization of Lanzarote basalts as a regolith simulant and lunar habitability resource

La búsqueda de análogos terrestres es crucial para el desarrollo de futuras bases lunares permanentes o semipermanentes. Los aná-logos terrestres son regiones donde es posible probar no solo instru-mental científico, sino también las capacidades de los astronautas en un entorno que, por su contexto geológico, geomorfológico, mi-neralógico, geoquímico, etc es similar al que podemos encontrar en Marte, la Luna e incluso asteroides. Este trabajo se ha centrado en la realización de una caracterización multianalítica de tres regiones de Lanzarote (Maciot, Tao y Lavas de Timanfaya) a través del empleo de diferentes técnicas geoquímicas y petrofísicas. Los resultados han sido comparados con los datos aportados por otros autores sobre muestras traídas de las misiones Apolo. Esto ha permitido determi-nar la analogía existente entre las regiones de estudio y la región de alunizaje del Apolo 14 conocida como Fra-Mauro. Además, se ha podido concluir qué recursos son potencialmente extraíbles del regolito lunar y su función en una futura base semipermanente. Por último, se propone la posibilidad de elaborar el primer simulante re-golítico lunar usando basalto de LanzaroteThe search for Terrestrial Analogues is essential for the deve-lopment of future permanent or semi-permanent lunar bases. Te-rrestrial Analogues are zones where it is possible to probe not only scientific instruments but also to other astronaut capabilities in an environment that is similar to the geological context, geomorpho-logy, mineralogical, geochemistry, etc that we can find on Mars, the Moon and even asteroids. This work has focused on a multi-analyti-cal characterization of three Lanzarote regions (Maciot, Tao y Lavas de Timanfaya), with different geochemical and petrophysical test. These results have been compared with data provided by other au-thors on samples brought from the Apollo missions. This has allowed to determine the analogy between the study regions and the Apollo 14 moon landing site known as Fra-Mauro formation. In addition, it is concluded which resources are potentially extractable from the Moon regolith and its function in a future semipermanent lunar base. Finally, it is proposed the possibility of developing the first Spa-nish lunar soil simulant through one of the Lanzarote basalt

Coordination between cell proliferation and apoptosis after DNA damage in Drosophila

Exposure to genotoxic stress promotes cell cycle arrest and DNA repair or apoptosis. These “life” or “death” cell fate decisions often rely on the activity of the tumor suppressor gene p53. Therefore, the precise regulation of p53 is essential to maintain tissue homeostasis and to prevent cancer development. However, how cell cycle progression has an impact on p53 cell fate decision-making is mostly unknown. In this work, we demonstrate that Drosophila p53 proapoptotic activity can be impacted by the G2/M kinase Cdk1. We find that cell cycle arrested or endocycle-induced cells are refractory to ionizing radiation-induced apoptosis. We show that p53 binding to the regulatory elements of the proapoptotic genes and its ability to activate their expression is compromised in experimentally arrested cells. Our results indicate that p53 genetically and physically interacts with Cdk1 and that p53 proapoptotic role is regulated by the cell cycle status of the cell. We propose a model in which cell cycle progression and p53 proapoptotic activity are molecularly connected to coordinate the appropriate response after DNA damag

Analysis of the ordinary chondrite of Dalgety Downs (L4): Mineralogy, geochemistry and Raman spectroscopy

El meteorito de Dalgety Downs, hallado en el Desierto de Australia Occidental, es una condrita ordinaria muy poco estudiada, que sin embargo contiene una valiosa información acerca de la evolución de la materia primitiva del Sistema Solar y los procesos que le afectan. Este ejemplar presenta unas características texturales, mineralógicas y geoquímicas en la matriz y cóndrulos que revelan procesos metamórficos de temperaturas intermedias y eventos de impacto moderados, además de una intensa alteración desarrollada durante su entrada en la atmósfera terrestre y su posterior exposición al clima, en lo que se define como la costra de fusión. Entre los métodos empleados en este estudio destaca la espectroscopía Raman como herramienta de identificación mineralógica, técnica que ha demostrado una gran precisión en materiales geológicos y que será empleada en próximas misiones espacialesThe Dalgety Downs meteorite, found in the Western Australian Desert, is a poorly studied ordinary chondrite, that however contains valuable information about the Solar System primitive matter evolution and the processes that affect it. This specimen exhibits textural, mineralogical and geochemical characteristics in matrix and chondrules that reveal metamorphic processes of intermediate temperatures and moderate impact events, in addition to an intense alteration developed during its entry into the terrestrial atmosphere and later exposure to climate, in what is defined as the fusion crust. Among the methods employed in this study, Raman spectroscopy highlights as a mineralogical identification tool, a technique of high precision in the analysis of geological materials and that is expected to be used in upcoming space mission

Charge analysis in (RE)CrO4 scheelites by combined Raman spectroscopy and computer simulations

The quest for structure-property relationships in scheelite-type (RE)CrO4 compounds (where RE is a rare earth element) is a difficult task due to the number of exceptions found in RE empirical trends and the uncommon Cr(V) oxidation state. In this work, we experimentally and computationally analyse how the stretching vibrational frequencies ν1(Ag) and ν3(Eg) associated with the [CrO4] tetrahedral units evolve in the (RE)CrO4 crystal family (RE ¼ Nd, Gd, Dy, Ho, and Lu). Since previously reported Cr–O distances and volume changes along with the RE series are not sufficiently accurate to explain the monotonic decrease observed for the ν1(Ag) and ν3(Eg) frequencies, a deeper analysis was performed involving the well-known fact that the bond strength (force constant) decreases as the interatomic distance increases. Our results demonstrates that structural and spectroscopic parameters can be reconciled with classical solid state chemistry ideas when charge effects are considered. This analysis provides a new method for predicting chromium oxidation states from Raman spectroscopy that can be generalised to the study of other crystal families

Highs and Lows of Bond Lengths: Is There Any Limit?

Two distinct points on the potential energy curve (PEC) of a pairwise interaction, the zero-energy crossing point and the point where the stretching force constant vanishes, allow us to anticipate the range of possible distances between two atoms in diatomic, molecular moieties and crystalline systems. We show that these bond-stability boundaries are unambiguously defined and correlate with topological descriptors of electron-density-based scalar fields, and can be calculated using generic PECs. Chemical databases and quantum-mechanical calculations are used to analyze a full set of diatomic bonds of atoms from the s-p main block. Emphasis is placed on the effect of substituents in C-C covalent bonds, concluding that distances shorter than 1.14 Å or longer than 2.0 Å are unlikely to be achieved, in agreement with ultra-high-pressure data and transition-state distances, respectively. Presumed exceptions are used to place our model in the correct framework and to formulate a conjecture for chained interactions, which offers an explanation for the multimodal histogram of O-H distances reported for hundreds of chemical systems

Pressure-Driven Metallization in Hafnium Diselenide

The quest for new transition metal dichalcogenides (TMDs) with outstanding electronic properties operating at ambient conditions draws us to investigate the 1T-HfSe2 polytype under hydrostatic pressure. Diamond anvil cell (DAC) devices coupled to in- situ synchrotron X-ray, Raman and optical (VIS-NIR) absorption experiments along with density functional theory (DFT) based calculations prove that: (i) bulk 1T-HfSe2 exhibits strong structural and vibrational anisotropies, being the interlayer direction especially sensitive to pressure changes, (ii) the indirect gap of 1T-HfSe2 trend to vanish by a -0.1 eV/GPa pressure rate, slightly faster than MoS2 or WS2, (iii) the onset of the metallic behavior appears at Pmet ~10 GPa, which is to date the lowest pressure among common TMDs, and finally (iv) the electronic transition is explained by the bulk modulus B0-Pmet correlation, along with the pressure coefficient of the band gap, in terms of the electronic overlap between chalcogenide p-type and metal d-type orbitals

Determinación de curvas para la estimación del contenido de humedad de diez maderas de frondosas mediante medidas de resistencia eléctrica

Accuracy in moisture content measurement is of great importance in the assurance of wood product quality and isnecessary to meet administrative and normative requirements. Improving the accuracy of resistance-type moisture meters,and meeting the normative demands of their annual calibration, requires the use of optimised curves relating electricalresistance to moisture content for the most commercially important wood types. The Samuelsson model, adjusted bylinear regression techniques, was used to describe the relationship between the electrical resistance and moisture contentof seven boreal and three tropical hardwoods available on the Spanish market. The curves produced can be used to predictthe moisture contents of these hardwoods via the measurement of their electrical resistance with an error of just ± 1.0%.These curves should also prove of great use in the calibration of wood resistance-type moisture meters.La precisión en la medida del contenido de humedad juega un papel fundamental no solo en el aseguramiento de lacalidad de los productos de la madera sino, también, en el cumplimiento de las exigencias normativas y administrativasque gravitan sobre los productos. Para ser capaces de mejorar la precisión de la medida tomada por los xilohigrómetrosde resistencia y cumplir con las exigencias normativas de calibración anual de los equipos, es necesario obtener curvasoptimizadas que relacionen la resistencia eléctrica con la humedad en las maderas de mayor importancia comercial.El modelo de Samuelsson, Log[Log(R) + 1] = a.h + b, ajustado mediante técnicas de regresión lineal, fue usado paradescribir la relación existente entre la resistencia eléctrica de la madera (R) y el contenido de humedad (h) de sietemaderas de frondosas boreales y tres de frondosas tropicales comercialmente disponibles en el mercado español. Lascurvas obtenidas pueden ser usadas para la predicción del contenido de humedad de dichas maderas, con un errormáximo de ± 1.0%, mediante la medición de su resistencia eléctrica. Estas curvas serían también de interés para lacalibración de medidores de humedad de madera por resistencia eléctrica

The Glial Regenerative Response to Central Nervous System Injury Is Enabled by Pros-Notch and Pros-NFκB Feedback

Organisms are structurally robust, as cells accommodate changes preserving structural integrity and function. The molecular mechanisms underlying structural robustness and plasticity are poorly understood, but can be investigated by probing how cells respond to injury. Injury to the CNS induces proliferation of enwrapping glia, leading to axonal re-enwrapment and partial functional recovery. This glial regenerative response is found across species, and may reflect a common underlying genetic mechanism. Here, we show that injury to the Drosophila larval CNS induces glial proliferation, and we uncover a gene network controlling this response. It consists of the mutual maintenance between the cell cycle inhibitor Prospero (Pros) and the cell cycle activators Notch and NFκB. Together they maintain glia in the brink of dividing, they enable glial proliferation following injury, and subsequently they exert negative feedback on cell division restoring cell cycle arrest. Pros also promotes glial differentiation, resolving vacuolization, enabling debris clearance and axonal enwrapment. Disruption of this gene network prevents repair and induces tumourigenesis. Using wound area measurements across genotypes and time-lapse recordings we show that when glial proliferation and glial differentiation are abolished, both the size of the glial wound and neuropile vacuolization increase. When glial proliferation and differentiation are enabled, glial wound size decreases and injury-induced apoptosis and vacuolization are prevented. The uncovered gene network promotes regeneration of the glial lesion and neuropile repair. In the unharmed animal, it is most likely a homeostatic mechanism for structural robustness. This gene network may be of relevance to mammalian glia to promote repair upon CNS injury or disease

Identification of Retinal Transformation Hot Spots in Developing Drosophila Epithelia

Background: The retinal determination (RD) network is an evolutionarily conserved regulatory circuit that governs early events in the development of eyes throughout the animal kingdom. Ectopic expression of many members of this network leads to the transformation of non-retinal epithelia into eye tissue. An often-overlooked observation is that only particular cell-populations within a handful of tissues are capable of having their primary developmental instructions superseded and overruled. Methodology/Preliminary Findings: Here we confirm that indeed, only a discrete number of cell populations within the imaginal discs that give rise to the head, antenna, legs, wings and halteres have the cellular plasticity to have their developmental fates altered. In contrast to previous reports, we find that all transformable cell populations do not lie within the TGFb or Hedgehog signaling domains. Additionally neither signaling cascade alone is sufficient for non-retinal cell types to be converted into retinal tissue. The transformation ‘‘hot spots’ ’ that we have identified appear to coincide with several previously defined transdetermination ‘‘weak spots’’, suggesting that ectopic eye formation is less the result of one network overriding the orders of another, as previously thought, but rather is the physical manifestation of redirecting cell populations of enormous cellular plasticity. We also demonstrate that the initiation of eye formation in non-retinal tissues occurs asynchronously compared to that of the normal eye suggesting that retinal development is not under the control o