Many Will Enter, Few Will Win: Cost and Sensitivity of Exploratory Dynamics.

A variety of biomolecular systems rely on exploratory dynamics to reach target locations or states within a cell. Without a mechanism to remotely sense and move directly towards a target, the system must sample over many paths, often including resetting transitions back to the origin. We investigate how exploratory dynamics can confer an important functional benefit: the ability to respond to small changes in parameters with large shifts in the steady-state behavior.

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.

A critical affinity window for IgSF proteins DIP-α and Dpr10 is required for proper motor neuron arborization.

For neurons to establish the correct connections in animal nervous systems, interactions between cell adhesion molecules (CAMs), expressed presynaptically and postsynaptically, are thought to guide neurons to their targets. Here, we assess the role that affinity between two cognate CAMs-DIP-α and Dpr10-plays in establishing the leg neuromuscular system in If affinity decreases or, surprisingly, increases past certain thresholds, motor neuron (MN) terminal branches fail to be maintained. Live imaging during development shows that when affinities are aberrant, MN filopodia are unable to productively engage their muscle targets.

Rigidity Criteria for Chainmail Consisting of Tessellations of Torus Knots.

Interlocked and polycatenated material systems, consisting of discrete, nonconvex particles linked to their nearest neighbors, such as chainmail fabrics, have been shown to undergo a jamming transition that increases their rigidity under boundary compression. This rigidity transition is associated with an increase in contact number between particles. In architected materials, rigidity is described by theories such as the Maxwell criterion.

The weak land carbon sink hypothesis.

Over the past three decades, assessments of the contemporary global carbon budget consistently report a strong net land carbon sink. Here, we review evidence supporting this paradigm and quantify the differences in global and Northern Hemisphere estimates of the net land sink derived from atmospheric inversion and satellite-derived vegetation biomass time series. Our analysis, combined with additional synthesis, supports a hypothesis that the net land sink is substantially weaker than commonly reported.

Evidence for Similar Collectivity of High Transverse-Momentum Particles in p-Pb and Pb-Pb Collisions.

Charged hadron elliptic anisotropies (v_{2}) are presented over a wide transverse momentum (p_{T}) range for proton-lead (pPb) and lead-lead (PbPb) collisions at nucleon-nucleon center-of-mass energies of 8.16 and 5.02 TeV, respectively.

Rapid Parameter Estimation for Pulsar-Timing-Array Datasets with Variational Inference and Normalizing Flows.

In the gravitational-wave analysis of pulsar-timing-array datasets, parameter estimation is usually performed using Markov chain Monte Carlo methods to explore posterior probability densities. We introduce an alternative procedure that instead relies on stochastic gradient-descent Bayesian variational inference, whereby we obtain the weights of a neural-network-based approximation of the posterior by minimizing the Kullback-Leibler divergence of the approximation from the exact posterior. This technique is distinct from simulation-based inference with normalizing flows since we train the network for a single dataset, rather than the population of all possible datasets, and we require the computation of the data likelihood and its gradient.

Prolonging All-Optical Molecular Electron Spin Coherence in the Tissue Transparency Window.

Coherent electron spin states within paramagnetic molecules hold significant potential for microscopic quantum sensing. However, all-optical coherence measurements amenable to high spatial and temporal resolution under ambient conditions remain a significant challenge. Here we conduct room-temperature, picosecond time-resolved Faraday ellipticity/rotation (TRFE/R) measurements of the electron spin decoherence time in [IrBr].

A view of the sustainable computing landscape.

This article presents a holistic research agenda to address the significant environmental impact of information and communication technology (ICT), which accounts for 2.1%-3.9% of global greenhouse gas emissions.

Structure, function and assembly of nuclear pore complexes.

The defining property of eukaryotic cells is the storage of heritable genetic material in a nuclear compartment. For eukaryotic cells to carry out the myriad biochemical processes necessary for their function, macromolecules must be efficiently exchanged between the nucleus and cytoplasm. The nuclear pore complex (NPC) - which is a massive assembly of ~35 different proteins present in multiple copies totalling ~1,000 protein subunits and architecturally conserved across eukaryotes - establishes a size-selective channel for regulated bidirectional transport of folded macromolecules and macromolecular assemblies across the nuclear envelope.

The effects of brines relevant to Mars and the ocean worlds on bacterial growth reflect salt-specific responses across water activity.

Freezing point depression due to high salt concentration is crucial for liquid water to exist on cold worlds, expanding special regions where habitats are plausible. Determination of the growth tolerances of terrestrial microbes in analog systems impacts planetary protection protocols aimed at preventing interference with life detection missions or potential native ecosystems on celestial bodies. We measured the salinity tolerances of 18 salinotolerant bacteria (Bacillus, Halomonas, Marinococcus, Nesterenkonia, Planococcus, Salibacillus, and Terribacillus).

In Vivo Whole-cell Patch-clamp Recording of Hypothalamic Peptidergic Neurons in Larval Zebrafish.

The hypothalamus is an ancient brain region that regulates diverse aspects of physiology and behavior, including sleep and wakefulness, appetite, energy homeostasis, anxiety, depression, and social interaction. Specific neuronal populations in the hypothalamus exert their effects via the release of neurotransmitters and neuropeptides. Whole-cell patch-clamp recording is an indispensable approach for studying the roles of these factors in synaptic transmission and brain function.

Grain boundary tuning determines iodide and lithium-ion migration in a solid adiponitrile-LiI molecular crystal electrolyte.

This work presents the synthesis of a molecular crystal of adiponitrile (Adpn) and LiI a simple melting method. The molecular crystal has both Li and I channels and can be either a Li or an I conductor. In the stoichiometric crystal (Adpn)LiI, the Li ions interact only with four CN groups of Adpn, while the I ions are uncoordinated.

Assessment of Myocardial Injury Size Metrics Using Carotid Pressure Waveform: Proof-of-Concept in Coronary Occlusion/Reperfusion Rat Model.

Myocardial infarction (MI) is a leading cause of death worldwide and the most common precursor to heart failure, even after initial treatment. Precise evaluation of myocardial injury is crucial for assessing interventions and improving outcomes. Extensive evidence from both preclinical models and clinical studies demonstrates that the extent and severity of myocardial injury (i.

Acute isolation is associated with increased reward seeking and reward learning in human adolescents.

Social connection, a basic human need, is vital during adolescence. How a lack of connection impacts adolescent behaviour is unclear. To address this question, we employed experimental short-term isolation with and without access to virtual social interactions (iso total; iso with media; order counterbalanced, both compared to a separate baseline session).

Tracking subtle seasonal shifts in pigment composition with hyperspectral reflectance in a temperate evergreen forest.

Pigment dynamics in temperate evergreen forests remain poorly characterized, despite their year-round photosynthetic activity and importance for carbon cycling. Developing rapid, nondestructive methods to estimate pigment composition enables high-throughput assessment of plant acclimation states. In this study, we investigate the seasonality of eight chlorophyll and carotenoid pigments and hyperspectral reflectance data collected at both the needle (400-2400 nm) and canopy (420-850 nm) scales in Pinus palustris (longleaf pine) at the Ordway Swisher Biological Station in north-central Florida, USA.

Distinct microbial communities within and on seep carbonates support long-term anaerobic oxidation of methane and divergent pMMO diversity.

At methane seeps worldwide, syntrophic anaerobic methane-oxidizing archaea and sulfate-reducing bacteria promote carbonate precipitation and rock formation, acting as methane and carbon sinks. Although maintenance of anaerobic oxidation of methane (AOM) within seep carbonates has been documented, its reactivation upon methane exposure remains uncertain. Surface-associated microbes may metabolize sulfide from AOM, maintain carbonate anoxia, contribute to carbonate dissolution, and support higher trophic levels; however, these communities are poorly described.

EPR and P ENDOR Characterization of Pseudo-Jahn-Teller Dynamics and N Activation in Functional Nitrogenase Models, PM(N) (M = Fe, Co; E = Si, B, C).

The nominally trigonal, pseudo-Jahn-Teller (PJT)-active, = 1/2 N-bound complexes, , M = Fe, Co, with three in-plane phosphine ligands and axial donors, E = Si, B, C, include functional nitrogenase models that catalyze the reduction of N to NH. We applied EPR, P ENDOR spectroscopy, and DFT computations to characterize the PJT-induced distortions of four selected , revealing how the metal ion and axial ligand E together tune both PJT dynamics, as revealed by P ENDOR and N activation, as indicated by a decrease in N≡N stretching frequency, ν(N≡N). , and each exhibit a single P isotropic hyperfine coupling, revealing dynamic pseudorotation of the PJT distortion, producing averaged symmetry with equivalent phosphine ligands.

Targeting YES1 enhances the efficacy of chemotherapy, targeted therapy and onco-immunotherapy.

YES1 (Yamaguchi sarcoma virus homolog 1), a non-receptor tyrosine kinase of the SRC family (SFK), has been abnormally amplified or mutated in several types of solid tumors. The alteration of YES1 impacted multiple biological processes, including promoting tumor progression and metastasis, especially, producing cancer therapy resistance via bypass pathways. Thus, YES1 can serve as a druggable target to overcome drug resistance and suppress tumor growth.

Improving cosmological reach of a gravitational wave observatory using Deep Loop Shaping.

Improved low-frequency sensitivity of gravitational wave observatories would unlock study of intermediate-mass black hole mergers and binary black hole eccentricity and provide early warnings for multimessenger observations of binary neutron star mergers. Today's mirror stabilization control injects harmful noise, constituting a major obstacle to sensitivity improvements. We eliminated this noise through Deep Loop Shaping, a reinforcement learning method using frequency domain rewards.

Mutant alleles enable a D-glutamate auxotroph to grow with lower requirements for exogenous D-glutamate.

D-glu is a key component of peptidoglycan (PG) and is essential for growth in most bacteria. To assess constraints on PG evolution and bacterial requirements for D-glu, we sought to artificially evolve PG biosynthesis, leading to either replacement of D-glu in the PG peptide or alternative pathways to D-glu incorporation. We previously found that suppression of D-glu auxotrophy in a mutant of grown on lysogeny broth salts (LBS) medium was rare but could be accomplished by mutation of , with restoration of wild-type PG structure.

33 Unresolved Questions in Nanoscience and Nanotechnology.

Significant advances in science and engineering often emerge at the intersections of disciplines. Nanoscience and nanotechnology are inherently interdisciplinary, uniting researchers from chemistry, physics, biology, medicine, materials science, and engineering. This convergence has fostered novel ways of thinking and enabled the development of materials, tools, and technologies that have transformed both basic and applied research, as well as how we address critical societal challenges.

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).

Targeted genomic analysis of a predominant uncultured marine pelagiphage-host model via microfluidics and semipermeable capsule technology.

Microbes and their viruses drive central biogeochemical cycles on a global scale. Understanding the biology and ecology of virus-host interactions and their impact on ecosystems depends on our ability to develop tools that enable high-throughput screening of ecologically relevant, uncultured virus-host pairs. Viruses infecting Pelagibacterales, the predominant bacteria in surface oceans, have been studied through computational analyses and cultivation efforts.

Blue light stimulated-autofluorescence green flash of lysosome-related organelles in the intestinal cells of nematodes.

The lysosome-related organelles ("gut granules") in the intestinal cells of many nematodes, including Caenorhabditis elegans, play an important role in metabolic and signaling processes, but they have not been fully characterized. We report here a previously undescribed phenomenon in which the autofluorescence of these granules displays a "flash" phenomenon in which fluorescence decreases are preceded by sharp increases in fluorescence intensity that expand into the surrounding area when the granules are stimulated with blue light. Autofluorescent granules are present in the intestinal cells of all six nematode species examined, with differences in morphology and distribution pattern.