Redox-driven mineral and organic associations in Jezero Crater, Mars.

The Perseverance rover has explored and sampled igneous and sedimentary rocks within Jezero Crater to characterize early Martian geological processes and habitability and search for potential biosignatures. Upon entering Neretva Vallis, on Jezero Crater's western edge, Perseverance investigated distinctive mudstone and conglomerate outcrops of the Bright Angel formation. Here we report a detailed geological, petrographic and geochemical survey of these rocks and show that organic-carbon-bearing mudstones in the Bright Angel formation contain submillimetre-scale nodules and millimetre-scale reaction fronts enriched in ferrous iron phosphate and sulfide minerals, likely vivianite and greigite, respectively.

Unveiling the Origin of Morphological Instability in Topologically Complex Electrocatalytic Nanostructures.

Coarsening and degradation phenomena in metals have largely focused on thermally driven processes, such as bulk and surface diffusion. However, dramatic coarsening has been reported in high-surface-area, nanometer-sized Pt-based catalysts during potential cycling in an electrolyte at room temperature─a temperature too low for the process to be explained purely by surface mobility values measured in both vacuum and electrolytes (∼10 and ∼10 cm/s, respectively). This morphological evolution must be due to a different mechanism for mass transport that is sensitive to electrochemical conditions (e.

Inverse Relationship Between Halophilic Growth and Cell Integrity Under Extremely Chaotropic Conditions.

Concentrated magnesium chloride brines are extreme environments that are inhospitable to life on Earth. The ionic strength of these brines significantly depresses water activity and concomitantly exerts significant chaotropic stress. Although these brines are largely considered sterile, the well-known preservative effects of magnesium chloride on certain biomolecules, such as DNA, confound life detection approaches and efforts to constrain precisely the habitable window of life on Earth.

The Psyche Gamma-Ray and Neutron Spectrometer.

A Gamma-Ray and Neutron Spectrometer (GRNS) instrument has been developed as part of the science payload for NASA's Discovery Program Psyche mission to the M-class asteroid (16) Psyche. The GRNS instrument is designed to measure the elemental composition of Psyche with the goal to understand the origin of this mysterious, potentially metal-rich planetary body. The GRNS will measure the near-surface abundances for the elements Ni, Fe, Si, K, S, Al, and Ca, as well as the spatial distribution of Psyche's metal-to-silicate fraction (or metal fraction).

Non-equilibrium critical scaling and universality in a quantum simulator.

Universality and scaling laws are hallmarks of equilibrium phase transitions and critical phenomena. However, extending these concepts to non-equilibrium systems is an outstanding challenge. Despite recent progress in the study of dynamical phases, the universality classes and scaling laws for non-equilibrium phenomena are far less understood than those in equilibrium.

A slot region in the magnetosphere of Jupiter.

Understanding the balance between charged particle acceleration and loss is central to radiation belt research. Jupiter's Galilean moons orbit within its intense radiation environment and can act both as sources and sinks of energetic particles. Using observations from the Juno spacecraft, we identify large-scale depletions of energetic electrons along Europa's orbit.

Human neural organoid microphysiological systems show the building blocks necessary for basic learning and memory.

Brain Microphysiological Systems, including neural organoids derived from human induced pluripotent stem cells, offer a unique lens to study the intricate workings of the human brain. This paper investigates the foundational elements of learning and memory in neural organoids by quantifying immediate early gene expression in response to chemical modulation, input-specific short- and long-term synaptic plasticity, neuronal network dynamics, connectivity, and criticality to demonstrate the utility of these organoids in basic science research. Neural organoids showed synapse formation, glutamatergic and GABAergic receptor expression, immediate early gene expression basally and evoked, functional connectivity, criticality, and synaptic plasticity in response to theta-burst stimulation.

The Lucky Engine: Probabilistic Emergence and Persistence of Near-Maximum Dissipation States.

A paradigm, wherein a nonequilibrium system has multiple modes of transport that can act in combination, permits the resolution of several difficulties with the notion of maximum entropy production (MaxEP or MEP). First, physical constraints, such as the density of the atmosphere or the planetary rotation rate, merely define the portfolio of modes that can be engaged by the system: physically impossible states cannot be selected. Second, with minimal sensitivity to how the system evolves, it is seen that there are simply more numerous quasi-steady microstates (combinations of modes) that are near the maximum of work output (or dissipation rate or EP) than there are far from it, and so it is more probable that the system will be observed to be near that maximum.

Estimating military working dog core temperature change with machine learning: A simulation study.

Military working dogs play a critical role in supporting the United States Military across various missions. Many missions occur in hot environments and predispose military working dogs to hyperthermia, a leading cause of their death. A previous effort created a physics-based model to estimate military working dog core temperature change based on dog attributes, metabolic activity, and environmental conditions.

High-gamma electrocorticography activity represents perceived vibration intensity in human somatosensory cortex.

Haptic feedback can play a useful role in rehabilitation and brain-computer interface applications by providing users with information about their system or performance. One challenge delivering tactile stimulation is not knowing how the haptic sensation is actually perceived, irrespective of the stimulation amplitude, during real-world use and beyond controlled psychophysical experiments. In a participant with chronically implanted electrocorticography arrays, we observed that perceived intensity of haptic vibration on the fingertips was represented in the high-gamma (HG) frequency band (70-170 Hz) in the somatosensory cortex.

Advancing next-generation brain organoid platforms for investigating traumatic brain injury from repeated blast exposures.

Service members and law enforcement personnel are frequently exposed to blast overpressure during training and combat due to the use of heavy weaponry such as large-caliber rifles, explosives, and ordnance. The cumulative effects of these repeated low-level (<4 psi) blast exposures can lead to physical and cognitive deficits that are poorly understood. Brain organoids-human stem cell-derived three-dimensional culture systems that self-organize to recapitulate the environment of the human brain-are a promising alternative biological model to traditional cellular cultures and animal models, offering a unique opportunity for studying the mechanisms of mild blast-induced traumatic brain injury (mbTBI) resulting from repeated exposure.

Identifying Areas with Low Access to the COVID-19 Vaccine: A New Objective Framework Incorporating Mobility Data.

Background: The disparities observed in COVID-19 vaccine access at the early stages of vaccine distribution highlight the need for vaccine distribution plans that consider equitable access. Strategies to identify areas with low access to vaccines that use a single pre-specified distance or time as a threshold to define accessibility may not represent reality. We propose a novel mobility data-driven (MDD) definition to identify areas that have low access to the COVID-19 vaccine.

Brain morphological characteristics predicting clinical response to selective serotonin reuptake inhibitors or cholinesterase inhibitors: A study of electronic medical records in patients with cognitive disorders.

Objectives: Current treatments for cognitive and neuropsychiatric symptoms in Alzheimer's disease and related dementias (ADRD), such as cholinesterase inhibitors (CEIs) and selective serotonin reuptake inhibitors (SSRIs), show inconsistent effectiveness, necessitating a personalized therapy approach. We aimed to develop predictive models using MRI-derived brain neuroanatomical features and clinical data to forecast responses to CEIs and SSRIs in ADRD patients.

Design And Setting: This was a retrospective observational analysis of electronic health records (EHRs) and MRI data conducted within Johns Hopkins Medical Systems.

Ternary materials discovery using human-in-the-loop generative machine learning.

Machine learning (ML) approaches to materials discovery are limited by data curation, availability, and bias. These issues can be addressed through the generation of new data points representing novel material compositions and/or structures. We demonstrate the implementation of this process to produce and subsequently determine the stability of novel materials using a generative ML model.

Nano-engineered thin-film thermoelectric materials enable practical solid-state refrigeration.

Refrigeration needs are increasing worldwide with a demand for alternates to bulky poorly scalable vapor compression systems. Here, we demonstrate the first proof of practical solid-state refrigeration, using nano-engineered controlled hierarchically engineered superlattice thin-film thermoelectric materials. With 100%-better thermoelectric materials figure of merit, ZT, than the conventional bulk materials near 300 K, we demonstrate (i) module-level ZT greater than 75% and (ii) a system-level refrigeration ZT 70% better than that of bulk devices.

Neurosymbolic AI as an antithesis to scaling laws.

The recent progress in machine learning has shifted the trends in artificial intelligence (AI) toward an overreliance on increasing amounts of data, computing power, and model parameters. These trends have resulted in success, but have also created a monolithic perspective for AI, increased the barriers to entry outside of large tech companies, and raised concerns about computational sustainability. Neurosymbolic AI is a growing area that promotes methodological heterogeneity and aims to push the frontiers of AI through affordable data and computing power.

Complete genome sequences of two shipworm endosymbiont strains, SR01903 and SR02026.

We present the complete genome sequences of two strains of , SR01903 and SR02026, shipworm endosymbionts isolated from the gills of and , respectively, and derived from Oxford Nanopore sequencing. These sequences will aid in the comparative genomics of shipworm endosymbionts and symbiosis model development.

The estrous cycle modulates hippocampal spine dynamics, dendritic processing, and spatial coding.

Histological evidence suggests that the estrous cycle exerts a powerful influence on CA1 neurons in the mammalian hippocampus. Decades have passed since this landmark observation, yet how the estrous cycle shapes dendritic spine dynamics and hippocampal spatial coding in vivo remains a mystery. Here, we used a custom hippocampal microperiscope and two-photon calcium imaging to track CA1 pyramidal neurons in female mice across multiple cycles.

Fluorescent Biomolecules Detectable in Near-Surface Ice on Europa.

Europa, Jupiter's second Galilean moon, is believed to host a subsurface ocean in contact with a rocky mantle, where hydrothermal activity may drive the synthesis of organic molecules. Among these possible organic molecules, abiotic synthesis of aromatic amino acids is unlikely, so their detection on planetary surfaces such as Europa suggests that they could be considered a potential biosignature. Fluorescence from aromatic amino acids, with characteristic emissions in the 200-400 nm wavelength range, can be induced by a laser and may be detectable where ocean material has been relatively recently emplaced on Europa's surface, as indicated by geologically young terrain and surface features.

Draft genome assemblies of ciprofloxacin-resistant derivatives of strain ATCC14579.

Ciprofloxacin resistance in involves diverse and understudied mechanisms. Here, we present draft genome assemblies of 95 experimentally evolved strains that exhibit increased growth in the presence of ciprofloxacin, many containing novel mutations not previously described for this phenotype.

Subthreshold intracortical microstimulation of human somatosensory cortex enhances tactile sensitivity.

Background: Intracortical microstimulation (ICMS) of the somatosensory cortex activates neurons around the stimulating electrodes and can elicit tactile sensations.

Objective: It is not clear how the direct activation of cortical neurons influences their ability to process additional tactile inputs originating from the skin.

Methods: In a human implanted with chronic microelectrode arrays in both left and right somatosensory cortices, we presented mechanical vibration to the skin while simultaneously delivering ICMS and quantified the effects of combined mechanical and electrical stimulation on tactile perception.

NEURD offers automated proofreading and feature extraction for connectomics.

We are in the era of millimetre-scale electron microscopy volumes collected at nanometre resolution. Dense reconstruction of cellular compartments in these electron microscopy volumes has been enabled by recent advances in machine learning. Automated segmentation methods produce exceptionally accurate reconstructions of cells, but post hoc proofreading is still required to generate large connectomes that are free of merge and split errors.

CAVE: Connectome Annotation Versioning Engine.

Advances in electron microscopy, image segmentation and computational infrastructure have given rise to large-scale and richly annotated connectomic datasets, which are increasingly shared across communities. To enable collaboration, users need to be able to concurrently create annotations and correct errors in the automated segmentation by proofreading. In large datasets, every proofreading edit relabels cell identities of millions of voxels and thousands of annotations like synapses.

New and revised gene ontology biological process terms describe multiorganism interactions critical for understanding microbial pathogenesis and sequences of concern.

Background: There is a new framework from the United States government for screening synthetic nucleic acids. Beginning in October of 2026, it calls for the screening of sequences 50 nucleotides or greater in length that are known to contribute to pathogenicity or toxicity for humans, regardless of the taxa from which it originates. Distinguishing sequences that encode pathogenic and toxic functions from those that lack them is not simple.