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DOE OSTI2025

Discovery and Development of a Small-Molecule Inhibitor Targeting the GAS41 YEATS Domain in Nonsmall Cell Lung Cancer

Abstract GAS41 is frequently overexpressed in Non-Small Cell Lung Cancer (NSCLC). GAS41 contains a YEATS domain, which recognizes acetylated lysine residues on histones to recruit protein complexes and facilitate transcription. Suppression of GAS41 in NSCLC models inhibits cellular proliferation and markedly reduces tumor growth in mouse xenografts, justifying the development of small-molecule inhibitors. We have employed structure-based design and medicinal chemistry optimization to discover DLG-41, a submicromolar inhibitor binding to the GAS41 YEATS domain. DLG-41 potently disrupts the association of GAS41 YEATS with chromatin in mammalian cells and inhibits the proliferation of NSCLC cell lines with submicromolar potency without significantly affecting normal lung fibroblasts. DLG-41 induces more effective growth inhibition in A549 versus GAS41-knockout cells, demonstrating on-target activity. DLG-41 treatment upregulates the CDKN1A gene and downregulates pathways associated with lung cancer cell identity, tumor migration, and invasion. DLG-41 is a promising chemical probe for targeting GAS41 protein in NSCLC models and has potential for future development.

Listunov, Dymytrii [University of Michigan , , , ,↗

NASA NTRS1994

Observational constraints on black hole accretion disks

We review the empirical constraints on accretion disk models of stellar-mass black holes based on recent multiwavelength observational results. In addition to time-averaged emission spectra, the time evolutions of the intensity and spectrum provide critical information about the structure, stability, and dynamics of the disk. Using the basic thermal Keplerian disk paradigm, we consider in particular generalizations of the standard optically thin disk models needed to accommodate the extremely rich variety of dynamical phenomena exhibited by black hole candidates ranging from flares of electron-positron annihilations and quasiperiodic oscillations in the X-ray intensity to X-ray novae activity. These in turn provide probes of the disk structure and global geometry. The goal is to construct a single unified framework to interpret a large variety of black hole phenomena. This paper will concentrate on the interface between basic theory and observational data modeling.

Liang, Edison P.↗

DOE OSTI2026

Neutron measurement from neutrino interactions in NOvA

The NuMI Off-Axis Appearance (NOvA) experiment is a long-baseline neutrino oscillation experiment based at Fermilab, consisting of two functionally identical liquid-scintillator detectors positioned slightly off-axis from the NuMI beam. It aims to probe CP violation in the lepton sector and determine the neutrino mass ordering by comparing the oscillation rates between the detectors. Given the energy dependence of oscillations, energy reconstruction is key--and a key limitation in the precision and accuracy of this kinematic variable is an understanding of primary neutron-related uncertainties since many may go undetected. While recent improvements have reduced discrepancies, NOvA's simulation still overpredicts neutron-linked activity by about 20\%, particularly for neutrons between 5–200 MeV. We present ongoing progress toward a measurement of neutron multiplicity in the NOvA Near Detector using spatially displaced and delayed energy deposits associated with neutron interactions, aiming to constrain neutron-related systematics and improve neutrino energy reconstruction in future oscillation analyses.

Kufatty, G. [Florida State U.]↗

NASA NTRS1996

Atomic and Molecular Data for Interstellar Studies: A Status Report

Most interstellar species have a large fraction of their electronic transitions at far ultraviolet wavelengths. Observations at these wavelengths reveal spectra rich in absorption lines seen against the continuum of a background source, such as a hot star in our Galaxy, a supernova in a nearby galaxy, or even a bright nucleus in an active galaxy. Most of the observations continue to be made with space-borne instruments, but recent work includes measurements of extragalactic material at large redshifts obtained at high resolution with large ground-based telescopes (e.g., the Keck Telescope). The combination of precise experimental oscillator strengths, large-scale computations, and astronomical spectra with high signal-to-noise ratios are yielding a set of self-consistent-values that span a range in strength in excess of 100 for more and more species. The large range is important for studies involving the different environments probed by the various background sources. This review highlights recent work on the atomic species. Si II, S I, and Fe II, and on the molecules, CO and C2.

Federman, Steven R.↗

DOE OSTI2024

Beyond the Bridge: Contention-Based Covert and Side Channel Attacks on Multi-GPU Interconnect

Recently, high-speed interconnects like NVLink have become a standard integration in modern multi-GPU systems, serving as a crucial bridge between CPUs and GPUs. This study highlights the vulnerability of multi-GPU systems to covert and side-channel attacks arising from congestion on these interconnects. An adversary, operating without special permissions, can extract private information about a victim's activities by monitoring NVLink congestion. Specifically, we leverage this insight to develop a covert channel attack across two GPUs, achieving a respectable bandwidth of 33 Kbps. Additionally, we introduce a side-channel attack that allows attackers to fingerprint applications on a remote GPU by probing the shared NVLink interconnect. We underscore the urgent nature of the threats posed by these attacks and advocate for heightened awareness within both industry and academia to implement multi-GPU interconnects with enhanced security measures.

Zhang, Yicheng↗

NASA NTRS1959

Project Mercury: Man-In-Space Program of the National Aeronautics and Space Administration

The purpose of this staff study, made at the request of the chairman, is to serve members of the Committee on Aeronautical and Space Sciences as a source of basic information on Project Mercury, the man-in-space program of the National Aeronautics and Space Administration. The study is largely derived from unclassified information released by the National Aeronautics and Space Administration and testimony concerning Project Mercury given during hearings before this committee. The program descriptions are based upon current program planning. Since this is a highly advanced research and development program, the project is obviously subject to changes that may result from future developments and accomplishments characteristic of such research activities. Certain information with respect to revised schedules, obtained on a classified basis by the committee during inspection trips, is necessarily omitted. The appendixes to the study include information that may prove helpful on various aspects of space flight and exploration. Included are unofficial comments and observations relating to Russia's manned space flight activities and also a complete chronology of all satellites, lunar probes, and space probes up to the present.

Source record↗

DOE OSTI2025

Luminosity and Stellar Mass Functions of Faint Photometric Satellites around Spectroscopic Central Galaxies from DESI Year-1 Bright Galaxy Survey

We measure the luminosity functions (LFs) and stellar mass functions (SMFs) of photometric satellite galaxies around spectroscopically identified isolated central galaxies (ICGs). The photometric satellites are from the DESI Legacy Imaging Surveys (DR9), while the spectroscopic ICGs are selected from the DESI Year-1 BGS sample. We can measure satellite LFs down to r-band absolute magnitudes of M r,sat ∼ −7, around ICGs as small as 7.1 < log 10 M *,ICG /M ⊙ < 7.8, with the stellar mass of ICGs measured by the DESI Fastspecfit pipeline. The satellite SMF can be measured down to log 10 M *,sat /M ⊙ ~ 5.5. Interestingly, we discover that the faint/low-mass end slopes of satellite LFs/SMFs become steeper with the decrease in the stellar masses of host ICGs, with smaller and nearby host ICGs capable of being used to probe their fainter satellites. The steepest slopes can be −2.298 ± 0.656 and −2.888 ± 0.916 for satellite LF and SMF, respectively. Detailed comparisons are performed between the satellite LFs around ICGs selected from DESI BGS or from the SDSS NYU-VAGC spectroscopic Main galaxies over 7.1 < log 10 M *,ICG /M ⊙ < 11.7, showing reasonable agreement, but we show that differences between DESI and SDSS stellar masses for ICGs play a role to affect the results. We also compare measurements based on DESI Fastspecfit and Cigale stellar masses used to bin ICGs, with the latter including the modeling of active galactic nuclei based on Wide-field Infrared Survey Explorer photometry, and we find good agreements in the measured satellite LFs by using either of the DESI stellar mass catalogs.

79 ASTRONOMY AND ASTROPHYSICS↗

NASA NTRS2007

Triaxial Probe Magnetic Data Analysis

The Triaxial Magnetic Moment Analysis software uses measured magnetic field test data to compute dipole and quadrupole moment information from a hardware element. It is used to support JPL projects needing magnetic control and an understanding of the spacecraft-generated magnetic fields. Evaluation of the magnetic moment of an object consists of three steps: acquisition, conditioning, and analysis. This version of existing software was extensively rewritten for easier data acquisition, data analysis, and report presentation, including immediate feedback to the test operator during data acquisition. While prior JPL computer codes provided the same data content, this program has a better graphic display including original data overlaid with reconstructed results to show goodness of fit accuracy and better appearance of the report graphic page. Data are acquired using three magnetometers and two rotations of the device under test. A clean acquisition user interface presents required numeric data and graphic summaries, and the analysis module yields the best fit (least squares) for the magnetic dipole and/or quadrupole moment of a device. The acquisition module allows the user to record multiple data sets, selecting the best data to analyze, and is repeated three times for each of the z-axial and y-axial rotations. In this update, the y-axial rotation starting position has been changed to an option, allowing either the x- or z-axis to point towards the magnetometer. The code has been rewritten to use three simultaneous axes of magnetic data (three probes), now using two "rotations" of the device under test rather than the previous three rotations, thus reducing handling activities on the device under test. The present version of the software gathers data in one-degree increments, which permits much better accuracy of the fit ted data than the coarser data acquisition of the prior software. The data-conditioning module provides a clean data set for the analysis module. For multiple measurements at a given degree, the first measurement is used. For omitted measurements, the missing field is estimated by linear interpolation between the two nearest measurements. The analysis module was rewritten for the dual rotation, triaxial probe measurement process and now has better moment estimation accuracy, based on the finer one degree of data acquisition resolution. The magnetic moments thus computed are used as an input to summarize the total spacecraft field.

Shultz, Kimberly↗

NASA NTRSDate not supplied

Spectrally Resolving High Redshift Dual AGNs with the Line Emission Mapper

The Line Emission Mapper (LEM) is an X-ray Probe-class Mission concept which combines 1-2 eV spectral resolution in the soft X-ray band (0.2-2 keV) with an effective area of ~2600 cm^2 at 1 keV, and 10’’ HPD over a large 30'x30' field of view. The mission will directly address the Astro2020 Decadal Report’s Priority Area of Unveiling the Drivers of Galaxy Growth through the study of merging galaxies, which offer one of the most dramatic channels for galaxy growth and evolution and can potentially trigger both star formation and supermassive black hole (SMBH) growth. Dual and binary AGNs in late-stage mergers are predicted to be a critical stage of merger-induced SMBH growth and coincide with the most transformative period for the host galaxies. Thus, dual and binary AGNs represent ideal laboratories for studying examples of SMBH-galaxy co-evolution. Recent discoveries of dual AGNs at redshifts of z~>2 have been made via optical observations, but such dual AGNs are inaccessible to current X-ray observatories due to a lack of instrumental capabilities, including sensitivity, spectral and spatial resolution. LEM will be uniquely suited to study AGNs at z > 3, where the intrinsic X-ray power law continuum and Iron K alpha emission line - a nearly ubiquitous signpost for AGN accretion – are redshifted into the LEM bandpass. In this poster, we present a simulation-based study on LEM’s ability to discern dual, binary, and/or clustered AGNs at high redshift. We demonstrate the unique capabilities of LEM to spectrally resolve Iron K-alpha lines emitted by distinct AGNs with sufficient line-of-sight velocity differences, even in cases of convolved point sources. Using a suite of simulations probing a range of velocity differences, line strengths, and column densities, we demonstrate LEM’s ability to constrain the spectral properties of dual AGNs at z>3 for a variety of physically realistic pairings. LEM will uniquely provide crucial constraints on dual AGN environments and activity as a function of redshift and will complement optical and infrared observations from upcoming Extremely Large Telescopes.

Ryan W Pfeifle↗

DOE OSTI2024

Observation of a Picosecond Light-Induced Spin Transition in Polymeric Nanorods

Spin transition (ST) materials are attractive for developing photoswitchable devices, but their slow material transformations limit device applications. Size reduction could enable faster switching, but the photoinduced dynamics at the nanoscale remains poorly understood. Here, we report a femtosecond optical pump multimodal X-ray probe study of polymeric nanorods. Simultaneously tracking the ST order parameter with X-ray emission spectroscopy and structure with X-ray diffraction, we observe photodoping of the low-spin–lattice within ~150 fs. Above a ~16% photodoping threshold, the transition to the high-spin phase occurs following an incubation period assigned to vibrational energy redistribution within the nanorods activating the molecular spin switching. Above ~60% photodoping, the incubation period disappears, and the transition completes within ~50 ps, preceded by the elastic nanorod expansion in response to the photodoping. These results support the feasibility of ST material-based GHz optical switching applications.

36 MATERIALS SCIENCE↗

DOE OSTI2026

A compact, low-power epithermal neutron counter for lunar water detection

The detection and characterization of lunar water are critical for enabling sustainable human and robotic exploration of the Moon. Orbital neutron spectrometers, such as instruments on Lunar Prospector and the Lunar Reconnaissance Orbiter, have revealed hydrogen-rich regions near the poles but are limited by coarse spatial resolution and low counting efficiency. We present a compact, lightweight, and low-power epithermal neutron detector based on boron-coated silicon imagers, designed to probe subsurface hydrogen at decimeter scales from mobile platforms such as lunar rovers. This instrument leverages the high neutron capture cross-section of 10 B to convert epithermal neutrons into detectable α and 7 Li ions in a fully-depleted silicon imager, providing a unique event topology to identify neutrons while suppressing backgrounds. Monte Carlo simulations demonstrate that a 3 μm boron layer achieves optimal neutron detection efficiency, further enhanced with polyethylene moderation to improve sensitivity to the 0.4 eV–500 keV epithermal energy range. For a 10 cm 2 active area, the detector achieves sensitivity to H 2 O weight fractions as low as 0.01 wt% in a 15 minute measurement. This scalable, portable, low-mass design is well-suited for integration into upcoming Artemis and commercial lunar rovers, providing a transformative capability for in-situ resource prospecting and ground-truth validation of orbital measurements.

Detector modelling and simulations I (interaction ↗

NASA NTRS2013

THEMIS Observations of the Magnetopause Electron Diffusion Region: Large Amplitude Waves and Heated Electrons

We present the first observations of large amplitude waves in a well-defined electron diffusion region based on the criteria described by Scudder et al at the subsolar magnetopause using data from one Time History of Events and Macroscale Interactions during Substorms (THEMIS) satellite. These waves identified as whistler mode waves, electrostatic solitary waves, lower hybrid waves, and electrostatic electron cyclotron waves, are observed in the same 12 s waveform capture and in association with signatures of active magnetic reconnection. The large amplitude waves in the electron diffusion region are coincident with abrupt increases in electron parallel temperature suggesting strong wave heating. The whistler mode waves, which are at the electron scale and which enable us to probe electron dynamics in the diffusion region were analyzed in detail. The energetic electrons (approx. 30 keV) within the electron diffusion region have anisotropic distributions with T(sub e(right angle))/T(sub e(parallel)) > 1 that may provide the free energy for the whistler mode waves. The energetic anisotropic electrons may be produced during the reconnection process. The whistler mode waves propagate away from the center of the "X-line" along magnetic field lines, suggesting that the electron diffusion region is a possible source region of the whistler mode waves.

magnetopause and boundary layers↗

NASA NTRS1994

New Computer Simulations of Macular Neural Functioning

We use high performance graphics workstations and supercomputers to study the functional significance of the three-dimensional (3-D) organization of gravity sensors. These sensors have a prototypic architecture foreshadowing more complex systems. Scaled-down simulations run on a Silicon Graphics workstation and scaled-up, 3-D versions run on a Cray Y-MP supercomputer. A semi-automated method of reconstruction of neural tissue from serial sections studied in a transmission electron microscope has been developed to eliminate tedious conventional photography. The reconstructions use a mesh as a step in generating a neural surface for visualization. Two meshes are required to model calyx surfaces. The meshes are connected and the resulting prisms represent the cytoplasm and the bounding membranes. A finite volume analysis method is employed to simulate voltage changes along the calyx in response to synapse activation on the calyx or on calyceal processes. The finite volume method insures that charge is conserved at the calyx-process junction. These and other models indicate that efferent processes act as voltage followers, and that the morphology of some afferent processes affects their functioning. In a final application, morphological information is symbolically represented in three dimensions in a computer. The possible functioning of the connectivities is tested using mathematical interpretations of physiological parameters taken from the literature. Symbolic, 3-D simulations are in progress to probe the functional significance of the connectivities. This research is expected to advance computer-based studies of macular functioning and of synaptic plasticity.

Ross, Muriel D.↗

DOE OSTI2024

Ultrapotent influenza hemagglutinin fusion inhibitors developed through SuFEx-enabled high-throughput medicinal chemistry

Seasonal and pandemic-associated influenza strains cause highly contagious viral respiratory infections that can lead to severe illness and excess mortality. Here, we report on the optimization of our small-molecule inhibitor F0045(S) targeting the influenza hemagglutinin (HA) stem with our Sulfur-Fluoride Exchange (SuFEx) click chemistry–based high-throughput medicinal chemistry (HTMC) strategy. A combination of SuFEx- and amide-based lead molecule diversification and structure-guided design led to identification and validation of ultrapotent influenza fusion inhibitors with subnanomolar EC 50 cellular antiviral activity against several influenza A group 1 strains. X-ray structures of six of these compounds with HA indicate that the appended moieties occupy additional pockets on the HA surface and increase the binding interaction, where the accumulation of several polar interactions also contributes to the improved affinity. The compounds here represent the most potent HA small-molecule inhibitors to date. Our divergent HTMC platform is therefore a powerful, rapid, and cost-effective approach to develop bioactive chemical probes and drug-like candidates against viral targets.

Science & Technology - Other Topics↗

DOE OSTI2025

Laminarin stimulates single cell rates of sulfate reduction whereas oxygen inhibits transcriptomic activity in coastal marine sediment

Abstract The chemical cycles carried out by bacteria and archaea living in coastal sediments are vital aspects of benthic ecology. These ecosystems are subject to physical disruption, which may allow for increased respiration and complex carbon consumption—impacting chemical cycling in this environment often thought to be a terminal place of deposition. We use the redox-enzyme sensitive probe RedoxSensor Green to measure rates of electron transfer physiology in individual sulfate reducer cells residing in anoxic sediment, subjected to transient exposure of oxygen and laminarin. We use index fluorescence activated cell sorting and single cell genomics sequencing to link those measurements to genomes of respiring cells. We measure per-cell sulfate reduction rates in marine sediments (0.01–4.7 fmol SO42− cell−1 h−1) and determine that cells within the Chloroflexota phylum are the most active in respiration. Chloroflexota respiration activity is also stimulated with the addition of laminarin, even in marine sediments already rich in organic matter. Evaluating metatranscriptomic data alongside this respiration-based technique, Chloroflexota genomes encode laminarinases indicating a likely ability to degrade laminarin. We also provide evidence that abundant Patescibacteria cells do not use electron transport pathways for energy, and instead likely carry out fermentation of polysaccharides. There is a decoupling of respiration-related activity rates from transcription, as respiration rates increase while transcription decreases with oxygen exposure. Overall, we reveal an active community of respiring Chloroflexota that cycles sulfate at potential rates of 23–40 nmol h−1 per cm3 sediment in incubation settings, and non-respiratory Patescibacteria that can cycle complex polysaccharides.

Lindsay, Melody R.↗

NASA NTRS1987

The frequency of enhanced star formation in interacting and isolated galaxies

To probe the sensitivity of the star formation rate and extent in galaxies to gravitational encounters, ground based near and mid-infrared and IRAS far-infrared measurements of complete samples of isolated and interacting pairs of galaxies were obtained. The observed infrared properties of the isolated galaxies are used to gauge the magnitude of star formation in galaxies free from external influences, and to define the relationships between morphological type and infrared luminosity. These properties were contrasted with those of the interacting sample to examine the extent to which interactions can enhance or alter the nature of star formation. The mechanisms by which interactions influence activity such as star formation are investigated through correlations of the infrared characteristics with radio and optical measurements, and with morphological and physical parameters such as galaxy types, separations, encounter velocities and interaction types. Limits to the physical extent of the star formation are obtained by comparing the large aperture measurements of IRAS with the small aperture ground based photometry.

Cutri, Roc M.↗

NASA NTRS1982

The lunar regolith - Chemistry, mineralogy, and petrology

The data base on the lunar regolith is surveyed to form a synthesis of the lunar regolith chemistry, mineralogy, and petrology. The data were derived from samples collected by the Apollo missions 11-17 and the Luna 16, 20, and 24 probes. The missions were sent to sample formations and areas which typified the common observed features of the lunar surface. Drive tubes were used to extract samples from beneath the surface in order to study the relationship between the regolith and the bedrock, as well as to identify the processes that formed the regolith, which is regarded as the prime source of raw materials for early lunar industrial activities. Regolith origins are now understood to be destructive processes of comminution and constructional processes of agglutinate formation. Mixing occurs on the local scale, although lateral transport is inefficient on the moon. The usual contents of the fraction of regolith less than 10 microns in diameter are Al2O3, CaO, Na2O, K2O, light REE, and Th.

Papike, J. J.↗

NASA NTRS2002

Study of the Imaging Capabilities of SPIRIT/SPECS Concept Interferometers

Several new space science mission concepts under development at NASA-GSFC for astronomy are intended to carry out synthetic imaging using Michelson interferometers or direct (Fizeau) imaging with sparse apertures. Examples of these mission concepts include the Stellar Imager (SI), the Space Infrared Interferometric Telescope (SPIRIT), the Submillimeter Probe of the Evolution of Cosmic Structure (SPECS), and the Fourier-Kelvin Stellar Interferometer (FKSI). We have been developing computer-based simulators for these missions. These simulators are aimed at providing a quantitative evaluation of the imaging capabilities of the mission by modeling the performance on different realistic targets in terms of sensitivity, angular resolution, and dynamic range. Both Fizeau and Michelson modes of operation can be considered. Our work is based on adapting a computer simulator called imSIM which was initially written for the Space Interferometer Mission in order to simulate the imaging mode of new missions such as those listed. This report covers the activities we have undertaken to provide a preliminary version of a simulator for the SPIRIT mission concept.

Allen, Ronald J.↗