Surface uplift and time-dependent seismic hazard due to fluid injection in eastern Texas

Observations that unequivocally link seismicity and wastewater injection are scarce. Here we show that wastewater injection in eastern Texas causes uplift, detectable in radar interferometric data up to >8 kilometers from the wells. Using measurements of uplift, reported injection data, and a poroelastic model, we computed the crustal strain and pore pressure. We infer that an increase of >1 megapascal in pore pressure in rocks with low compressibility triggers earthquakes, including the 4.8–moment magnitude event that occurred on 17 May 2012, the largest earthquake recorded in eastern Texas. Seismic activity increased even while injection rates declined, owing to diffusion of pore pressure from earlier periods with higher injection rates. Induced seismicity potential is suppressed where tight confining formations prevent pore pressure from propagating into crystalline basement rocks.

Shirzaei, M.; Ellsworth, W. L.; Tiampo, K. F.; Gonzalez, P. J.; Manga, M.

Science 353 (6306): 1416-1419 (2016)
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High‐resolution digital elevation model from tri‐stereo Pleiades‐1 satellite imagery for lava flow volume estimates at Fogo Volcano

Resolving changes in topography through time using accurate high‐resolution digital elevation models (DEMs) is key to understanding active volcanic processes. For the first time in a volcanic environment, we utilize very high‐resolution tri‐stereo optical imagery acquired by the Pleiades‐1 satellite constellation and generate a 1 m resolution DEM of Fogo Volcano, Cape Verde—the most active volcano in the Eastern Atlantic region. Point cloud density is increased by a factor of 6.5 compared to conventional stereo imagery, and the number of 1 m2 pixels with no height measurements is reduced by 43%. We use the DEM to quantify topographic changes associated with the 2014–2015 eruption at Fogo. Height differences between the posteruptive Pleiades‐1 DEM and the preeruptive topography from TanDEM‐X give a lava flow volume of 45.83 ± 0.02 × 106 m3, emplaced over an area of 4.8 km2 at a mean rate of 6.8 m3 s−1.

Bagnardi, Marco; González, Pablo J.; Hooper, Andrew

Geophysical Research Letters 43(12): 6267-627 (2016)
DOI

Application of isothermal titration calorimetry as a tool to study natural product interactions

Over the past twenty-five years, isothermal titration calorimetry (ITC) has become a potent tool for the study a great variety of molecular interactions. This technique is able to provide a complete thermodynamic profile of an interaction process in a single experiment, with a series of advantages in comparison to other comparable techniques, such as less amount of sample or no need of chemical modification or labelling. It is thus not surprising that ITC has been applied to study the manifold types of interactions of natural products to get new insights into the molecular key factors implied in the complexation process of this type of compounds. This review provides an overview over the applications of ITC as a potent tool to investigate interactions of natural products with proteins, nucleic acids, oligosaccharides, and other types of receptors. The examples have been selected depending on the impact that this technique had during the investigation and revision of the interactions involved in the bioactivity of a compound, lead optimization or technical applications.

Callies, Oliver; Hernández Daranas, Antonio

 

 

Natural Product Reports 33(7): 881-904 (2016)
DOIDigital.CSIC

Sesquiterpenoids isolated from two species of the Asteriscus Alliance

Investigation of the aerial parts of two Spanish members of the Asteriscus alliance, Asteriscus graveolens subsp. stenophyllus and Asteriscus schultzii, afforded four new sesquiterpene lactones containing a humulene skeleton (1–4) and one new sesquiterpene lactone of the asteriscanolide type (5). Their chemical structures were determined on the basis of the HRMS and from 1D and 2D NMR spectroscopic studies. Both species showed different profiles of sesquiterpenoid constituents. A. schultzii did not show humulene or asteriscane sesquiterpenes, suggesting a resemblance to the genus Pallenis, another member of the Asteriscus alliance. A literature review on chemical isolates from the Asteriscus alliance supported the placement of A. schultzii in the genus Pallenis. The isolated components (1–5) were assessed for cytotoxicity against the HL-60 and MOLT-3 leukemia cell lines, with compound 1 showing activity in both biological assays (IC50 value range 4.1–5.4 μM).

 Triana, Jorge; Eiroa, José L.; Morales, Manuel; Pérez, Francisco Javier; Brouard, Ignacio; Quintana, José; Ruiz-Estévez, Mercedes; Estévez, Francisco; León, Francisco 

Journal of Natural Products 79(5): 1292-1297 (2016)
DOIDigital.CSIC

Propargyl Vinyl Ethers and Tertiary Skipped Diynes: Two Pluripotent Molecular Platforms for Diversity-Oriented Synthesis

During the last years, we have been involved in the development of a diversity-oriented synthetic strategy aimed at transforming simple, linear, and densely functionalized molecular platforms into collections of topologically diverse scaffolds incorporating biologically relevant structural motifs such as N- and O- heterocycles, multifunctionalized aromatic rings, fused macrocycles, etc. The strategy merges the concepts of pluripotency (the property of an array of chemical functionalities to express different chemical outcomes under different chemical environments) and domino chemistry (chemistry based on processes involving two or more bond-forming transformations that take place while the initial reaction conditions are maintained, with the subsequent reaction resulting as a consequence of the functionality installed in the previous one) to transform common multifunctional substrates into complex and diverse molecular frameworks. This design concept constitutes the ethos of the so-called branching cascade strategy, a branch of diversity-oriented synthesis focused on scaffold diversity generation. Two pluripotent molecular platforms have been extensively studied under this merging (branching) paradigm: C4–O–C3 propargyl vinyl ethers (PVEs) and C7 tertiary skipped diynes (TSDs). These are conveniently constructed from simple and commercially available raw materials (alkyl propiolates, ketones, aldehydes, acid chlorides) through multicomponent manifolds (ABB′ three-component reaction for PVEs; A2BB′ four-component reaction for TSDs) or a simple two-step procedure (for PVEs). Their modular origin facilitates their structural/functional diversification without increasing the number of synthetic steps for their assembly. These two pluripotent molecular platforms accommodate a well-defined and dense array of through-bond/through-space interrelated functionalities on their structures, which defines their primary reactivity principles and establishes the reactivity profile. The PVEs are defined by the presence of an alkyne (alkynoate) function and a conjugated enol moiety and their mutual through-bond/through-space connectivity. This functional array accommodates a number of domino reactions launched either by a Michael addition on the alkynoate moiety (conjugated alkynes) or by a [3,3]-propargyl Claisen rearrangement (conjugated and nonconjugated alkynes). The reactivity profile of the TSDs is defined by the two connected alkynoate moieties (Michael addition) and the bispropargylic ester group ([3,3]-sigmatropic rearrangement). Using these first reactivity principles, each platform selectively delivers one unique and different skeleton (topology) from each domino transformation. Thus, through the use of 11 instrumentally simple and scalable domino reactions, we have transformed these two linear (rod-symmetric) pluripotent molecular platforms into 16 different scaffolds incorporating important structural motifs and multifunctional decorative patterns. The generated scaffolds entail carbocycles, heterocycles, aromatics, β,γ-unsaturated esters and acids, and fused polycycles. They can be transformed into more elaborated molecular skeletons by the use of chemical handles generated in their own domino reactions or by appending different functionalities to the pluripotent molecular platform (secondary reactivity principles).

Tejedor, David; López-Tosco, Sara ; Méndez-Abt, Gabriela; Cotos, Leandro; García-Tellado, Fernando

Accounts of Chemical Research 49(4): 703–713 (2016)
DOIDigital.CSIC

Oxysterols from an octocoral of the genus Gorgonia from the eastern Pacific of Panama

Eighteen new oxysterols have been isolated from a previously undescribed octocoral collected from the eastern Pacific of Panama. Their structures were determined based on spectroscopic evidence. The absolute configuration was established by derivatization with (R)- and (S)-MPA. Antimicrobial and antileishmanial effects were evaluated.

Cardoso-Martínez, F.; Rosa, José M. de la ; Díaz-Marrero, Ana R.; Darias, José; D'Croz, Luis; Jiménez-Antón, M. Dolores; Corral, María Jesús; García, Rocío; Alunda Rodríguez, Jose María; Cueto, Mercedes

RSC Advances 6: 38579-38591 (2016)
DOIDigital.CSIC

Sustainable oxidations with air mediated by gallic acid: potential applicability in the reutilization of grape pomace

Gallic acid converts atmospheric oxygen into hydrogen peroxide, which is able to oxidize arylboronic acids as a proof of concept of sustainable oxidations. Moreover, tannic acid and grape pomace extract are also able to perform oxidations with air. Therefore this work unleashes an alternative method for reutilization and valorization of bio-wastes rich in tannins.

J. Scoccia, M. D. Perretti, D. M. Monzón, F. P. Crisóstomo, V. S. Martín, R. Carrillo

Green Chemistry, 2016,18, 2647-2650
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Phytotoxic and Nematicidal Components of Lavandula luisieri

Several preparations were obtained from the aerial parts of predomesticated Lavandula luisieri, including the essential oil and ethanolic, hexane, and ethyl acetate extractives. Additionally, pilot plant vapor pressure extraction was carried out at a Several preparations were obtained from the aerial parts of predomesticated Lavandula luisieri, including the essential oil and ethanolic, hexane, and ethyl acetate extractives. Additionally, pilot plant vapor pressure extraction was carried out at a pressure range of 0.5–1.0 bar to give a vapor pressure oil and an aqueous residue. A chemical study of the hexane extract led to the isolation of six necrodane derivatives (1, 2, and 4–7), with four of these (1, 2, 5, and 7) being new, as well as camphor, a cadinane sesquiterpene (9), tormentic acid, and ursolic acid. The EtOAc and EtOH extracts contained a mixture of phenolic compounds with rosmarinic acid being the major component. Workup of the aqueous residue resulted in the isolation of the necrodane 3 and (1R*,2S*,4R*)-p-menth-5-ene-1,2,8-triol (8), both new natural compounds. The structures of the new compounds were established based on their spectroscopic data. The phytotoxic and nematicidal activities of these compounds were evaluated.

Julio, Luis F.; Barrero, Alejandro F.; Herrador del Pino, María del Mar; Arteaga, Jesús F.; Burillo Alquézar, Jesús; Andrés, Mª Fé; Díaz, Carmen E.; González-Coloma, Azucena.

Journal of Natural Products 79(2): 261-266 (2016)
DOIDigital.CSIC

Radical C-H arylations of (hetero)arenes catalysed by gallic acid

Gallic acid efficiently catalyses radical arylations in water–acetone at room temperature. This methodology proved to be versatile and scalable. Therefore, it constitutes a greener alternative to arylation. Moreover, considering that gallic acid is an abundant vegetable tannin, this work also unleashes an alternative method for the reutilisation of bio-wastes.

M. D. Perretti, D. M. Monzón, F. P. Crisóstomo, V. S. Martín, R. Carrillo

Chemical Communications, 2016,52, 9036-9039
DOI

Himalayan megathrust geometry and relation to topography revealed by the Gorkha earthquake

The Himalayan mountain range has been the locus of some of the largest continental earthquakes, including the 2015 magnitude 7.8 Gorkha earthquake. Competing hypotheses suggest that Himalayan topography is sustained and plate convergence is accommodated either predominantly on the main plate boundary fault, or more broadly across multiple smaller thrust faults. Here we use geodetic measurements of surface displacement to show that the Gorkha earthquake ruptured the Main Himalayan Thrust fault. The earthquake generated about 1 m of uplift in the Kathmandu Basin, yet caused the high Himalaya farther north to subside by about 0.6 m. We use the geodetic data, combined with geologic, geomorphological and geophysical analyses, to constrain the geometry of the Main Himalayan Thrust in the Kathmandu area. Structural analyses together with interseismic and coseismic displacements are best explained by a steep, shallow thrust fault flattening at depth between 5 and 15 km and connecting to a mid-crustal, steeper thrust. We suggest that present-day convergence across the Himalaya is mostly accommodated by this fault—no significant motion on smaller thrust faults is required. Furthermore, given that the Gorkha earthquake caused the high Himalayan mountains to subside and that our fault geometry explains measured interseismic displacements, we propose that growth of Himalayan topography may largely occur during the ongoing post-seismic phase.

Elliott, J. R.; Jolivet, R.; González, P. J.; Avouac, J.-P.; Hollingsworth, J.; Searle, M. P.; Stevens, V. L. 

Nature Geoscience 9: 174–180 (2016)
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