Reprocessable and Recyclable Materials for 3D Printing via Reversible Thia-Michael Reactions.

The development of chemically recyclable polymers for sustainable 3D printing is crucial to reducing plastic waste and advancing towards a circular polymer economy. Here, we introduce a new class of polythioenones (PCTE) synthesized via Michael addition-elimination ring-opening polymerization (MAEROP) of cyclic thioenone (CTE) monomers. The designed monomers are straightforward to synthesize, scalable and highly modular, and the resulting polymers display mechanical performance superior to commodity polyolefins such as polyethylene and polypropylene.

pyVPT2: Interoperable software for anharmonic vibrational frequency calculations.

We present pyVPT2, a program to perform second-order vibrational perturbation theory (VPT2) computations to obtain anharmonic vibrational frequencies. This program is written in Python and can utilize any of the several quantum chemistry programs that have been interfaced to the QCEngine project of the Molecular Sciences Software Institute (MolSSI). The requisite single point energy, gradient, or Hessian computations can be automatically performed in a distributed-parallel fashion by optionally using the MolSSI's QCFractal software.

Transformation-Guided Genome Mining Provides Access to Brominated Lanthipeptides.

Natural product biosynthesis is nature's tinkering ground for developing new enzymes that can achieve chemical transformations that are outside the purview of traditional chemical catalysis. Herein we describe a genome mining approach that leads to the discovery of a halogenase that regioselectively brominates a tryptophan side chain indole for a macrocyclic peptide substrate, enabling downstream chemical arylation by Suzuki-Miyaura coupling. The halogenase was found to prefer a macrocyclic peptide substrate over a linear peptide.

Mg-dependent mechanism of environmental versatility in a multidrug efflux pump.

Tripartite resistance nodulation and cell division multidrug efflux pumps span the periplasm and are major drivers of multidrug resistance among gram-negative bacteria. Cations, such as Mg, become concentrated within the periplasm and, in contrast to the cytoplasm, its pH is sensitive to conditions outside the cell. Here, we reveal an interplay between Mg and pH in modulating the structural dynamics of the periplasmic adapter protein, AcrA, and its function within the prototypical AcrAB-TolC multidrug pump from Escherichia coli.

Spaceflight alters protein levels and gene expression associated with stress response and metabolic characteristics in human cardiac spheroids.

Cardiomyocytes derived from human induced pluripotent stem cells (hiPSC-CMs) possess tremendous advantage for cardiac regeneration. However, cell survival is challenging upon cell transplantation. Since microgravity can profoundly affect cellular properties, we investigated the effect of spaceflight on hiPSC-CMs.

Discovery of Peptidic Siderophore Degradation by Screening Natural Product Profiles in Marine-Derived Bacterial Mono- and Cocultures.

Coral reefs are hotspots of marine biodiversity, which results in the synthesis of a wide variety of compounds with unique molecular scaffolds, and bioactivities, rendering reefs an ecosystem of interest. The chemodiversity stems from the intricate relationships between inhabitants of the reef, as the chemistry produced partakes in intra- and interspecies communication, settlement, nutrient acquisition, and defense. However, the coral reefs are declining at an unprecedented rate due to climate change, pollution, and increased incidence of pathogenic diseases.

Amplicon Sequencing Reveals Diversity in Spatially Separated Microbial Communities in the Icelandic Mars Analog Environment Mælifellssandur.

Exploration missions to Mars rely on landers or rovers to perform multiple analyses over geographically small sampling regions, while landing site selection is done using large-scale but low-resolution remote-sensing data. Utilizing Earth analog environments to estimate small-scale spatial and temporal variation in key geochemical signatures and biosignatures will help mission designers ensure future sampling strategies meet mission science goals. Icelandic lava fields can serve as Mars analog sites due to conditions that include low nutrient availability, temperature extremes, desiccation, and isolation from anthropogenic contamination.

Substructure-Specific Antibodies Against Fentanyl Derivatives.

Structural variants of the synthetic opioid fentanyl are a major threat to public health. Following an investigation showing that many derivatives are poorly detected by commercial lateral flow and related assays, we created hapten conjugate vaccines using an immunogenic virus-like particle carrier and eight synthetic fentanyl derivatives designed to mimic the structural features of several of the more dangerous analogues. Immunization of mice elicited strong antihapten humoral responses, allowing the screening of hundreds of hapten-specific hybridomas for binding strength and specificity.

AND-gated protease-activated nanosensors for programmable detection of anti-tumour immunity.

The forward design of biosensors that implement Boolean logic to improve detection precision primarily relies on programming genetic components to control transcriptional responses. However, cell- and gene-free nanomaterials programmed with logical functions may present lower barriers for clinical translation. Here we report the design of activity-based nanosensors that implement AND-gate logic without genetic parts via bi-labile cyclic peptides.

Nanoscale characterization of space weathering in lunar samples.

Nanoscale Fourier transform infrared (Nano-FTIR) imaging and spectroscopy correlated with photoluminescence measurements of lunar Apollo samples with different surface radiation exposure histories reveal distinct physical and chemical differences associated with space weathering effects. Analysis of two sample fragments: an ilmenite basalt (12016) and an impact melt breccia (15445) show evidence of intrinsic or delivered Nd and an amorphous silica glass component on exterior surfaces, whereas intrinsic Cr and/or trapped electron states are limited to interior surfaces. Spatially localized 1050 cm/935 cm band ratios in Nano-FTIR hyperspectral maps may further reflect impact-induced shock nanostructures, while shifts in silicate band positions indicate accumulated radiation damage at the nanoscale from prolonged space weathering due to micrometeorites, solar wind, energetic x-rays and cosmic ray bombardment.

Rational Fabrication of Functionally-Graded Surfaces for Biological and Biomedical Applications.

As a ubiquitous feature of the biological world, gradation, in either composition or structure, is essential to many functions and processes. Taking protein gradation as an example, it plays a pivotal role in the development and evolution of human bodies, including stimulation and direction of the outgrowth of peripheral nerves in a developing fetus. It is also critically involved in wound healing by attracting and guiding immune cells to the site of injury or infection.

Frustrated Magnetism and Spin Anisotropy in a Buckled Square Net YbTaO.

The interplay between quantum effects from magnetic frustration, low-dimensionality, spin-orbit coupling, and crystal electric field in rare-earth materials leads to nontrivial ground states with unusual magnetic excitations. Here, we investigate YbTaO, which hosts a buckled square net of Yb ions with = 1/2 moments. The observed Curie-Weiss temperature is about -1 K, implying an antiferromagnetic coupling between the Yb moments.

Thermally Stable Anthracene-Based 2D/3D Heterostructures for Perovskite Solar Cells.

Bulky organic cations are used in perovskite solar cells as a protective barrier against moisture, oxygen, and ion diffusion. However, bulky cations can introduce thermal instabilities by reacting with the near-surface of the 3D perovskite forming low-dimensional phases, including 2D perovskites, and by diffusing away from the surface into the film. This study explores the thermal stability of CsFAPbI 3D perovskite surfaces treated with two anthracene salts─anthracen-1-ylmethylammonium iodide (AMAI) and 2-(anthracen-1-yl)ethylammonium iodide (AEAI)─and compares them with the widely used phenethylammonium iodide (PEAI).

Continuous-Flow and Scalable Synthesis of Pd@Pt Core-Shell Nanocrystals with Enhanced Activity toward Oxygen Reduction.

We report a scalable method based on continuous-flow reactors for conformally coating the surfaces of facet-controlled Pd nanocrystals with uniform, ultrathin shells made of Pt. The key to the success of such an approach is the identification of a proper polyol to generate the Pt atoms at a relatively slow rate to ensure adequate surface diffusion and thus the formation of uniform shells in a layer-by-layer fashion. We first demonstrate the concept using the production of Pd@Pt (n = 2-5) core-shell icosahedral nanocrystals and then have the strategy successfully extended to the syntheses of Pd@Pt cubic and octahedral nanocrystals.

Equipping a Wyatt multiangle, multidetector instrument for real-time particle and polymer sizing by simultaneous multiple-angle dynamic and static light scattering.

Well-constructed instruments may continue to perform beyond their manufacturer-supported service lifetime, which is typically limited by computer operating system compatibility or the availability of spare parts. Often, such equipment is condemned to surplus and destroyed. End-of-life plans that retain some of the material and energy used to create scientific instruments are of interest, just as in other manufacturing sectors.

Fast and Facile Synthesis of Cobalt-Doped ZIF-8 and FeO/MCC/Cobalt-Doped ZIF-8 for the Photodegradation of Organic Dyes under Visible Light.

Co-doped ZIF-8 as a water-stable visible light photocatalyst was prepared by using a one-pot, fast, cost-effective, and environmentally friendly method. The band structure of ZIF-8 was tuned through the incorporation of different percentages of cobalt to attain an optimal band gap ( ) that enables the activation of ZIF-8 under visible light and minimizes the recombination of photogenerated charge carriers. A magnetic composite of Co-doped ZIF-8 was also synthesized to facilitate catalyst recycling and reusability through the application of an external magnetic field.

Salts of 2-amino-5-iodo-pyridinium.

Reaction of 2-amino-5-iodo-pyridine (5IAP) with concentrated HBr at room temperature yielded 2-amino-5-iodo-pyridinium bromide, CHIN ·Br or (5IAPH)Br. The complex formed pale-yellow crystals, which exhibit significant hydrogen bonding between the amino and pyridinium N-H donors and bromide ion acceptors. Halogen bonding is also observed.

Consensus Recommendations for Studies of Outflow Facility and Intraocular Pressure Regulation Using Ex Vivo Perfusion Approaches.

Intraocular pressure (IOP) elevation is the primary risk factor and currently the main treatable factor for progression of glaucomatous optic neuropathy. In addition to direct clinical and living animal in vivo studies, ex vivo perfusion of anterior segments and whole eyes is a key technique for studying conventional outflow function as it is responsible for IOP regulation. We present well-tested experimental details, protocols, considerations, advantages, and limitations of several ex vivo model systems for studying IOP regulation.

Early Technology Readiness Level (TRL) Development of the Microfluidic Inorganic Conductivity Detector for Europa and the Solenoid-Based Actuator Assembly for Impact Penetrators.

This study introduces an innovative in situ lander/impact-penetrator design tailored for Discovery-class missions to Europa, specifically focused on conducting astrobiological analyses. The platform integrates a microfluidic capacitively coupled contactless conductivity detector (C4D), optimized for the detection of low-concentration salts potentially indicative of biological activity. Our microfluidic system allows for automated sample routing and precise conductivity-based detection, making it suitable for the harsh environmental and logistical demands of Europa's icy surface.

Elucidation of the Active Agents in a West African Ground Herbal Medicine Formulation That Elicit Antimalarial Activities in In Vitro and In Vivo Models.

Agunmu (ground herbal medicine) is a form of West African traditional medicine consisting of a cocktail of herbs. The goal of this study is to evaluate a formulation of Agunmu made from , , , , and , sold in the open market and commonly used for the treatment of malaria by the locals, for its antimalarial effects and to determine the active principles that may contribute to the antimalarial effect. The ethanolic extract obtained from this formulation (Ag-Iba) was analyzed, using TLC, LC-MS, and Tandem-MS techniques, to determine its phytochemical properties.

Manipulating Backbone Planarity of Ester Functionalized Conjugated Polymer Constitutional Isomer Derivatives Blended with Molecular Acceptors for Controlling Photovoltaic Properties.

Exploring both electron donor and acceptor phase components in bulk heterojunction structures has contributed to the advancement of organic photovoltaics (OPV) realizing power conversion efficiencies reaching 20%. Being able to control backbone planarity of the donor polymer, while understanding its effects on the polymer conformation and photophysical properties, fosters the groundwork for further achievements in this realm. In this report, three isomeric PM7 derivatives are designed and synthesized where the benzodithiophene-4,8-dione structure is replaced by a quaterthiophene bridge carrying two ester moieties.

Targeting MarA N-terminal domain dynamics to prevent DNA binding.

Efflux is one of the mechanisms employed by Gram-negative bacteria to become resistant to routinely used antibiotics. The inhibition of efflux by targeting their regulators is a promising strategy to re-sensitize bacterial pathogens to antibiotics. AcrAB-TolC is the main resistance-nodulation-division efflux pump in Enterobacteriaceae.

Live cell imaging of lipid droplets: fluorescent chalcones as probes for lipophagy and lipid-mitochondria interactions.

Lipid droplets are crucial organelles involved in cellular energy storage and metabolism, which is key in maintaining energy homeostasis through lipophagy. In this work, we successfully synthesized donor-acceptor chalcone derivatives (M1-M3) with improved photophysical characteristics, such as significant Stokes shifts and strong emission features. DFT and TDDFT calculations have been employed to evaluate the structure-property relationship of the chalcone derivatives.