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Photochromic radionuclide-based “claw machines” characterizedviaa combination of isothermal titration calorimetry and spectroscopic analysis unlock a pathway for on demand radionuclide capture and release. 

Transformers have revolutionized machine learning, yet their inner workings remain opaque to many. We present TRANSFORMER EXPLAINER, an interactive visualization tool designed for non-experts to learn about Transformers through the GPT-2 model. Our tool helps users understand complex Transformer concepts by integrating a model overview and smooth transitions across abstraction levels of math operations and model structures. It runs a live GPT-2 model locally in the user’s browser, empowering users to experiment with their own input and observe in real-time how the internal components and parameters of the Transformer work together to predict the next tokens. 125,000 users have used our open-source tool at https://poloclub.github.io/ transformer-explainer/. 

Autistic and neurotypical children do not handle audiovisual speech in the same manner. Current evidence suggests that this difference occurs at the level of cue combination. Here, we test whether differences in autistic and neurotypical audiovisual speech perception can be explained by a neural theory of sensory perception in autism, which proposes that heightened levels of neural excitation can account for sensory differences in autism. Through a linking hypothesis that integrates a standard probabilistic cognitive model of cue integration with representations of neural activity, we derive a model that can simulate audio-visual speech perception at a neural population level. Simulations of an audiovisual lexical identification task demonstrate that heightened levels of neural excitation at the level of cue combination cannot account for the observed differences in autistic and neurotypical children's audiovisual speech perception. 

Regulation of ion channel expression on the plasma membrane is a major determinant of neuronal excitability, and identifying the underlying mechanisms of this expression is critical to our understanding of neurons. Here, we present two orthogonal strategies to label extracellular sites of the ion channel TRPV1 that minimally perturb its function. We use the amber codon suppression technique to introduce a non-canonical amino acid (ncAA) with tetrazine click chemistry, compatible with a trans-cyclooctene coupled fluorescent dye. Additionally, by inserting the circularly permutated HaloTag (cpHaloTag) in an extracellular loop of TRPV1, we can incorporate a fluorescent dye of our choosing. Optimization of ncAA insertion sites was accomplished by screening residue positions between the S1 and S2 transmembrane domains with elevated missense variants in the human population. We identified T468 as a rapid labeling site (∼5 min) based on functional and biochemical assays in HEK293T/17 cells. Through adapting linker lengths and backbone placement of cpHaloTag on the extracellular side of TRPV1, we generated a fully functional channel construct, TRPV1exCellHalo, with intact wild-type gating properties. We used TRPV1exCellHalo in a single molecule experiment to track TRPV1 on the cell surface and validate studies that show decreased mobility of the channel upon activation. The application of these extracellular label TRPV1 (exCellTRPV1) constructs to track surface localization of the channel will shed significant light on the mechanisms regulating its expression and provide a general scheme to introduce similar modifications to other cell surface receptors. 

Abstract Conjugated polymer brush (CPB) films are more robust and exhibit more vertically aligned polymer chains than their spun‐cast analogs. We prepare CPB films of poly(3‐hexylthiophene) (P3HT) by coupling an amine‐terminated surface (ATS) formed from (3‐aminopropyl)triethoxysilane (APTES) on Si/SiO₂to 4‐bromobenzoic acid using standard, inexpensive peptide coupling reagents. The resulting terminal bromobenzene is reacted with Pd(PtBu₃)₂and immersed in the monomer solution. X‐ray photoelectron spectroscopy, spectroscopic ellipsometry and static water contact angle measurements confirm the surface chemistry at each stage of P3HT CPB preparation. Atomic force microscopy(AFM) and UV–vis spectrophotometry indicate that the CPB films prepared by this method exhibit similar morphology and optical properties to those produced from other methods of poly(3‐alkylthiophene) CPB film preparation. Variations of the standard approach, such as using a pre‐synthesized silane counterpart or with (11‐aminoundecyl)triethoxysilane, show comparable film morphologies by AFM. This method is used to produce the first CPB film of poly(3‐dodecylthiophene), showing its utility for exploring CPB films of more sterically demanding polymers. Peptide coupling is used to prepare an analogous functionalized thiol for initiating P3HT CPB film growth from Au surfaces, and microcontact printing with this thiol allows preparation of the first patterned CPB film of P3HT. 

Bridging the current gap between the precision and efficiency demonstrated by natural systems and synthetic materials requires interfacing and independently controlling multiple stimuli-responsive building blocks in a single platform. The mentioned orthogonal control over material properties (i.e., the ability to selectively activate one stimuli-responsive moiety without affecting another) could pave the way for a multitude of applications, including logic-gated optoelectronics, on-demand drug delivery platforms, and molecular shuttles, for example. In this Review, we highlight the recent successful strategies to achieve orthogonal control over material properties using a combination of stimuli-responsive building blocks and multiple independent stimuli. We begin by surveying the fundamental studies of multi-stimuli-responsive systems, which utilize a variety of stimuli to activate a single stimuli-responsive moiety (e.g., spiropyran, diarylethene, or dihydroazulene derivatives), because these studies lay the foundation for the design of systems containing more than one independently controlled fragment. As a next step, we overview the emerging field focusing on systems which are composed of more than one unique stimuli-responsive unit that can respond to independent stimuli, including distinct excitation wavelengths, or a combination of light, heat, pH, potential, or ionic strength. Recent advances clearly demonstrate how strategic coupling of orthogonally controlled stimuli-responsive units can allow for selective modulation of a range of material properties, such as conductivity, catalytic performance, and biological activity. Thus, the highlighted studies foreshadow the emerging role of materials with orthogonally controlled properties to impact the next generation of photopharmacology, nanotechnology, optoelectronics, and biomimetics.