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Chronological feed of everything captured from roon.

paper / tszzl / Jun 7

CISS Effect Asymmetry Between Enantiomers May Explain Why Life Chose D-RNA Over L-RNA

The chirality-induced spin selectivity (CISS) effect has previously been proposed to explain how life achieved homochirality via enantioselective interactions with magnetic substrates like magnetite. This work extends that model by demonstrating that spin-dependent processes are not merely enantioselective but produce quantitatively different outcomes in the two enantiomers of a chiral molecule — resolving the deeper mystery of *which* handedness was selected, not just *that* one was. The mechanism hinges on the total angular momentum vector J aligning differently relative to the molecular frame in each enantiomer, despite having the same magnitude, leading to differential efficiency in spin-related phenomena such as magnetic surface interactions. Measurements, theory, and ab initio calculations are all reported in support of the findings, published in Science Advances.

chiralityspin-selectivitychemical-physicshomochiralityorigin-of-lifequantum-chemistrymolecular-physics
“The total angular momentum vector J aligns differently relative to the molecular frame in the two enantiomers of a chiral molecule, despite having the same magnitude.”
paper / tszzl / Jun 7

Spin-Polarized Charge Injection as a Mechanism for Allosteric Protein Control

Researchers demonstrate that photoinduced charge redistribution within a protein directly modulates its functional behavior, establishing electrical polarization as a legitimate allosteric signal. Using a ruthenium photosensitizer site-specifically attached to phosphoglycerate kinase (PGK), they show that charge injection can increase antibody binding 2-fold and suppress enzymatic activity by up to 3-fold. Critically, only left circularly polarized light elicits these effects, implicating spin-polarized electron transport mediated by the chiral structure of the protein — a direct in-protein demonstration of the CISS (Chirality-Induced Spin Selectivity) effect.

protein-functionbioelectricityspin-polarizationphotochemistryallosteric-regulationbiophysicschiral-structures
“Photoinduced charge redistribution in PGK increases antibody binding affinity by approximately 2-fold under illumination.”
paper / tszzl / Jun 7

Sharper Amenability Bounds for Local Coordination Games via Shapley-Weighted Mutual Information

Peretz and Kraizberg improve quantitative bounds connecting low-disagreement local coordination games on finite social networks to graph amenability. Prior work by Hutchcroft, Rospuskova, and Tamuz established that low inefficiency implies amenability but with a square-root loss in the amenability parameter. By deploying Shapley values of a mutual-information game over players' local outputs, the authors tighten this to an O(ε log(1/ε)) bound in the binary unbiased case, nearly closing the gap to linear. This yields a sharper converse: near-perfect local coordination is a near-necessary condition for graph amenability.

game-theorygraph-theorycoordination-gamesinformation-theoryshapley-valuessocial-networkscombinatorics
“If average disagreement in a binary unbiased local coordination game is at most ε, then the underlying graph is (O(ε log(1/ε)), r)-amenable.”
paper / tszzl / Jun 7

Bacterial Extracellular Electron Conduits Exhibit Spin-Selective Transport via CISS Effect

Multiheme cytochromes (MtrF and OmcA) on the surface of Shewanella oneidensis MR-1 — which enable long-distance (>10 nm) extracellular electron transfer to solid minerals and electrodes — have been demonstrated to exhibit spin-selective electron transport. Using magnetic conductive probe AFM, Hall voltage measurements, and spin-dependent electrochemistry, the authors link this selectivity to the chirality-induced spin selectivity (CISS) effect. This finding extends CISS, previously studied in isolated biomolecules, to functional bacterial electron conduits operating at biotic-abiotic interfaces. The results suggest that magnetic fields and spin-dependent interactions may be exploitable levers for controlling microbial electrochemistry in both natural geochemical and biotechnological contexts.

spin-selectivityelectron-transportcytochromeextracellular-electron-transferbiophysicschemical-physicsmicrobiology
“Electron transport through decaheme cytochromes MtrF and OmcA is spin-selective.”
paper / tszzl / Jun 7

Robust Bone Angle Estimation in Medical Imaging Outperforms Landmark Methods Using RANSAC and Hough Transforms

This paper presents a learning-based pipeline for automated bone pose estimation in X-ray and ultrasound images, combining point candidate proposals with robust line-fitting techniques (RANSAC, Hough transforms) to extract bone axis angles. The approach directly addresses the sensitivity of conventional least-squares fitting to outliers through false-positive reduction strategies. Evaluated on three pediatric clinical tasks — fracture fragment assessment in radiographs and ultrasound, and Graf-method hip dysplasia evaluation — the method achieves mean angular errors between 4.1° and 5.51°, staying within clinical observer variability and significantly outperforming landmark-based baselines.

medical-imagingpose-estimationcomputer-visiondeep-learningx-ray-ultrasoundrobust-fittingpediatric-diagnostics
“The proposed method achieves mean angular errors of 4.1°, 5.4°, and 5.51° on three pediatric clinical bone angle estimation tasks.”