Pierre-Gilles de Gennes Institute

Landscape level observations of streams on the island of Hawai’i indicate that runoff ratios are essentially zero on the young active volcanic surfaces of windward Mauna Loa and Kilauea volcanoes and increase with age on the older Mauna Kea and Kohala surfaces. Recent work on both permanent and ephemeral stream flows shows that the changes in runoff are associated with decreases in saturated hydraulic conductivity (kh) and aquifer thickness (D) that change with surface age (Perez-Fodich et al. 2024). The processes that control k in soils are plausibly related to weathering but the mechanisms are complex. Chemical weathering causes mass loss and most weathering reactions have negative ∆V so intuitively weathering should increase porosity (f) and likely kh. Dry bulk density rs of weathered soils initially does decrease with weathering mass losses. However trends in rs reverse with further age, and calculated soil strain becomes negative. A model of poro-plastic deformation where the medium comprises an incompressible matrix with a finite yield stress and a void fraction f that is deformable but has zero yield stress (e.g. Gurson (1977)) can represent the evolution of soil strain if is a function of weathering mass loss. In this model the overall plastic yield limit is a function of both and f. The constitutive relation between chemical alteration and strength of the residual soil matrix is not known in detail. I hypothesize that the yield stress of the residual matrix is a function of the loss of network-forming components such as SiO2, and that the change in yield stress can be described with a power law function of an alteration and mass loss index such as enrichment in an immobile element Nb/Nb0. The resulting change in soil hydraulic properties diminishes vertical infiltration and promotes lateral flow toward incipient streams. The resulting incision leads to marked landscape level changes in hydrology and geomorphology, enhanced by incising stream capture of groundwater in shallow aquifers.

Liquid biopsy, in particular circulating tumor DNA (ctDNA) analysis, has paved the way for a new noninvasive approach to cancer diagnosis, treatment selection and follow-up. As a crucial step in the analysis, the extraction of the genetic material from a complex matrix needs to meet specific requirements such as high specificity and low loss of target. Here, we developed a new generation of microfluidic fluidized beds (FBs) that enable the efficient extraction and preconcentration of specific ctDNA sequences from human serum with flow rates up to 15 µL/min. We first demonstrated that implementation of a vibration system inducing flow rate fluctuations combined with a mixture of different bead sizes significantly enhanced bead homogeneity, thereby increasing capture efficiency. Taking advantage of this new generation of high-throughput magnetic FBs, we then developed a new method to selectively capture a double-stranded (dsDNA) BRAF mutated DNA sequence in complex matrices such as patient serum. Finally, as proof of concept, ligation chain reaction (LCR) assays were performed to specifically amplify a mutated BRAF sequence, allowing the detection of concentrations as low as 6 × 104 copies/µL of the mutated DNA sequence in serum.

Here we present a method to reduce the photobleaching of fluorescent proteins and the associated phototoxicity. It exploits a photophysical process known as reverse intersystem crossing, which we induce by near-infrared co-illumination during fluorophore excitation. This dual illumination method reduces photobleaching effects 1.5–9.2-fold, can be easily implemented on commercial microscopes and is effective in eukaryotic and prokaryotic cells with a wide range of fluorescent proteins.

L'éruption explosive du volcan Hunga Tonga - Hunga Ha’apai (HTHH), le 15 janvier 2022, a<br> produit la plus puissante explosion enregistrée depuis les explosions du Krakatau et du Tambora dans<br> les années 1800, libérant une énergie équivalente à 110 mégatonnes de TNT. Les ondes générées se<br> sont propagées dans le sol, et dans l’atmosphère jusqu’à l’ionosphère. L'onde atmosphérique la plus<br> énergétique observée sur les baromètres correspond au mode de Lamb. De période supérieure à 2000<br> s, son amplitude est comparable à celle observée lors de l’éruption du Krakatau en 1883. L’empreinte<br> des perturbations atmosphériques a été caractérisée à l’échelle planétaire par des réseaux de mesures<br> au sol, à bord de satellites ou de plateformes aéroportées. L’analyse combinée de ces observations a<br> permis d’évaluer les conséquences à court terme de l'éruption du HTHH. Les méthodes d'investigation<br> géophysiques présentées dans cette note montrent l’apport d’analyses interdisciplinaires pour<br> caractériser la réponse impulsionnelle des enveloppes fluides planétaires (atmosphère, océans et<br> mers) à une éruption d’une intensité exceptionnelle.

In the version of this article initially published, the third sentence of the abstract, now reading "This is a key question because single whole-genome duplication events such as cytokinesis failure can promote tumorigenesis 9 and DNA double-strand breaks 10 " was truncated and did not mention double-strand breaks or cite ref. 10 (Pedersen, R. S. et al. Profiling DNA damage response following mitotic perturbations. Nat. Commun.

Earth and Space Science Open Archive This preprint has been submitted to and is under consideration at Journal of Geophysical Research - Atmospheres. ESSOAr is a venue for early communication or feedback before peer review. Data may be preliminary.Learn more about preprints preprintOpen AccessYou are viewing the latest version by default [v1]Atmospheric deposition over the Caribbean region: sea salt and Saharan dust are sources of essential elements on the island of GuadeloupeAuthorsYangjunjieXUiDCelineDessertRémiLosnoiDSee all authors Yangjunjie XUiDCorresponding Author• Submitting AuthorUniversité Paris Cité, Institut de Physisque du Globe de ParisiDhttps://orcid.org/0000-0002-3543-2239view email addressThe email was not providedcopy email addressCeline DessertUniv. Paris Diderot - Sorbonne Paris Cite- IPGPview email addressThe email was not providedcopy email addressRémi LosnoiDUniversite de Paris - IPGPiDhttps://orcid.org/0000-0003-0246-862Xview email addressThe email was not providedcopy email address

&amp;lt;p&amp;gt;NASA&amp;amp;#8217;s InSight mission deployed the Seismic Experiment for Interior Structure (SEIS) instrument on Mars, with the goal of detecting, discriminating, characterizing and locating the seismicity of Mars and study its internal structure, composition and dynamics. 44 years since the first attempt by the Viking missions, SEIS has revealed that Mars is seismically active. So far, the Marsquake Service (MQS) has identified 365 events that cannot be explained by local atmospheric or lander-induced vibrations, and are interpreted as marsquakes. We identify two families of marsquakes: (i) 35 events of magnitude MW=3-4, dominantly long period in nature, located below the crust and with waves traveling inside the mantle, and (ii) 330 high-frequency events of smaller magnitude and of closer distance, with waves trapped in the crust, exciting an ambient resonance at 2.4Hz. Two long period events with larger SNR and excellent P and S waves occurred on Sol 173 and 235, visible both on the VBB and the SP channels; the location of these events has been determined at distances of 26&amp;amp;#176;-30&amp;amp;#176; towards the East, close to the Cerberus Fossae tectonic system. Over ten additional long period events show consistent body-wave phases interpreted as P and S phases and can be aligned with distance using models of P and S propagation. Marsquakes have spectral characteristics similar to seismicity observed on the Earth and Moon. From the spectral characteristics of the recorded seismicity and the event distance, we constrain attenuation in the crust and mantle, and find indications of a potential low S-wave-velocity layer in the upper mantle. In contrast, the high-frequency events provide important constraints on the elastic and anelastic properties of the crust. The first seismic observations on Mars deliver key new knowledge on the internal structure, composition and dynamics of the red planet, opening a new era for planetary seismology. Here we review the seismicity detected so far on Mars, including location, distance, magnitude, magnitude-frequency distribution, tectonic context and possible seismic sources.&amp;lt;/p&amp;gt;

This activity introduces droplet-based millifluidics and the usage of aqueous droplets as independent chemical microreactors for reaction-kinetics studies. Students build their own droplet generators from common macroscopic glassware and connecting parts to create trains of millimeter-sized droplets in which a redox reaction takes place. The activity allows students to work on reaction kinetics, hydrodynamics at low Reynolds numbers, and image analysis at the macroscopic scale.