Massachusetts Institute of Technology

Polyglycine Strands Within a Collagen Triple Helix

ABSTRACT The collagen triple helix is the most abundant protein structural motif in animals. It tolerates any amino acid in its Xaa and Yaa positions but demands glycine (Gly) at every third position, where the residue packs into the sterically forbidding core of the triple helix...

Efficient and accurate steering of large language models through attention-guided feature learning

Activation steering, or direct manipulation of internal activations to guide large language model (LLM) responses toward specific semantic concepts, is emerging as a promising avenue for both understanding how semantic concepts are stored within LLMs and advancing LLM capabilitie...

Perverse sheaves and $t$-structures on the thin and thick affine flag varieties

We study the categories \mathrm{Perv}_{\mathrm{thin}} , \mathrm{Perv}_{\mathrm{thick}} of Iwahori-equivariant perverse sheaves on the thin and thick affine flag varieties associated to a split reductive group G . An earlier work of the first author describes \mathrm{Perv}_{\mathr...

Modeling of vibrational non-equilibrium in detonation with global kinetics

One-, two-, and three-step global kinetic models that include thermal non-equilibrium were developed for detonation simulations using the open-source software Cantera and the Shock and Detonation Toolbox (SDToolbox). The rate coefficients and thermodynamic parameters of these mod...

On Distributionally Robust Multistage Convex Optimization: New Algorithms and Complexity Analysis

Abstract. This paper presents an algorithmic study and complexity analysis for solving distributionally robust multistage convex optimization (DR-MCO) problems. Our main contribution is a novel nonconsecutive dual dynamic programming (NDDP) algorithm which explores different stag...

Embedded Morgan Fingerprints for More Efficient Molecular Property Predictions With Machine Learning

High‐dimensional molecular fingerprints have become a quiet bottleneck for chemical machine learning, where bit collisions in large, chemically diverse datasets and escalating computational costs constrain model discovery. This work introduces the embedded Morgan Fingerprint (eMF...

The Evolution of Low-ionization Electron Densities in Galaxies across Cosmic Epochs

Abstract We investigate the low-ionization electron density in the interstellar medium (ISM) of galaxies across 0 < z < 8, derived with the [O ii ] λλ 3727, 3730 and [S ii ] λλ 6718, 6733 doublets, using both deep JWST/NIRCam/grism and NIRSpec/MSA spectroscopy. Along with ancilla...

Long‐Term Increase in Equatorial Rayleigh‐Taylor Instability: Synergistic Effects of Greenhouse Gas Cooling and Geomagnetic Field Secular Variation

Abstract Equatorial plasma bubbles (EPBs) are ionospheric irregularities generated by Rayleigh–Taylor instability (RTI) that disrupt satellite communications. We quantify secular change of RTI growth rates and isolate underlying drivers using WACCM‐X simulations. Results reveal a...

Computation-through-Dynamics Toolkit: Simulated datasets and quality metrics for dynamical models of neural activity

A primary goal of systems neuroscience is to discover how ensembles of neurons transform inputs into goal-directed behavior, a process known as neural computation. A powerful framework for understanding neural computation uses neural dynamics – the rules that govern how neural ac...

Cohesin Mutations in Cancer and Development

Cohesin is a ring-shaped protein complex that wraps around DNA and is crucial for sister chromatid cohesion, chromatin organization, gene regulation, replication, and DNA damage repair. In somatic cells, it consists of the core ring subunits SMC1A, SMC3, and RAD21 and one of two...

Gene-rich fungus gnat germline-restricted chromosomes are largely transcriptionally quiescent

Germline-restricted chromosomes (GRCs) constitute a unique class of chromosomes confined to germ cells. Arising in multiple evolutionarily distant lineages, GRCs have been identified in three insect families (non-biting midges, gall midges, and fungus gnats), each within the orde...

Impact of Backbone Fluorination on Self-Assembly and Mixed Conduction of Isoindigo-Based Polymers

Abstract Fluorination is a common method to induce backbone planarity in semiconducting polymers via noncovalent interactions that effectively lock the rotation of single bonds along the backbone. Often explored in dry-state devices, fluorination of isoindigo polymer backbones in...

Laboratory Measurements of Energy Partitioning and Anomalous Electron Heating in Magnetized, Perpendicular Collisionless Shocks

Abstract We present laboratory results on energy partitioning from supercritical, magnetized collisionless shock experiments ( M A ∼ 8, M ms ∼ 4). We report the first observation of fully developed laboratory shocks that evolve for more than seven upstream ion gyroperiods and hav...

Non‐Perturbative Bacterial Identification Directly From Solid Agar Plates Using Raman Micro‐Spectroscopy and Machine Learning

ABSTRACT Raman spectroscopy is a promising tool for microbial identification, yet its implementation in microbiology and clinical workflow is still restricted due to the accompanying additional preparation required to focus on microbial signals. Here, we demonstrate Raman‐based b...

System design of the Ultra Mobility Vehicle: A driving, balancing, and jumping bicycle robot

Trials cyclists and mountain bike riders can hop, jump, balance, and drive on one or both wheels. This versatility allows them to achieve speed and energy efficiency on smooth terrain and agility over rough terrain. Inspired by these athletes, we present the design and control of...

Enerzyme: An Efficient Reactive Neural Network Potential Training Framework for Enzyme Cluster Models with Application to Methyltransferases

Abstract Quantum mechanical (QM) cluster models provide an effective framework for mechanistic studies of enzymatic reactions but QM calculations remain computationally demanding. Neural network potentials (NNPs) offer a promising route to reduce their cost, but enzymes introduce...

Machine Learning on Heterogeneous, Edge, and Quantum Hardware for Particle Physics

The next generation of particle physics experiments will face an era of challenges in data acquisition, due to unprecedented data rates and volumes along with extreme environments and operational constraints. Harnessing these data for scientific discovery demands real-time infere...

Subvarieties of low degree on general hypersurfaces

Abstract The purpose of this note is to show that the subvarieties of small degree inside a general hypersurface of large degree come from intersecting with linear spaces or other varieties. This partially generalizes a theorem of Wu.

Improving neuropathological reconstruction fidelity via AI slice imputation

Neuropathological analyses benefit from spatially precise volumetric reconstructions that enhance anatomical delineation and improve morphometric accuracy. Prior work has shown the feasibility of reconstructing 3D brain volumes from 2D dissection photographs. However, these outpu...

An analytical model for rotors in confined flow across operating regimes

Rotors operating in confined flows, or blockage, are commonly encountered in wind and water tunnels, as well as in shallow or dense deployments of hydrokinetic turbines. Confinement induces a streamwise pressure gradient in the channel, modifying the rotor induction, thrust and p...