Extreme ultraviolet induced reactions of tin–oxo cage photoresists

The performance of photoresists is a major challenge in extreme ultraviolet (EUV) lithography and needs to be improved for the future technology nodes that require higher resolution, patterning fidelity, and sensitivity. Hybrid inorganic/organic materials are considered for this crucial function, but the chemical mechanisms underlying their solubility switching are not well understood, which hampers the rational improvement of EUV photoresists. Here we study n-butyltin–oxo cages, a readily accessible "open source" representative negative tone resist. Upon exposure to EUV radiation (wavelength 13.5 nm), butane, butene and octane are the main volatile reaction products. Tin is fully retained in the films even after prolonged EUV exposure. It is found that the loss of only ∼18% of the butyl groups suffices to render the resist film insoluble. The initial quantum efficiency of Sn–C bond cleavage is Φ ≈ 5 per absorbed EUV photon, but this decreases rapidly with conversion of the material. After the primary Sn–C bond cleavage in a tin–oxo cage, induced by photoionization or capture of a (secondary) photoelectron, facile thermal reaction steps may occur that lead to additional Sn–C bond breaking. Although many questions remain, our work sheds new light on the reaction mechanisms at play and provides input for simulations of the lithographic process

Subscale stress-managed asymmetric common coil design

In the context of the high-field magnet program, the Swiss Accelerator Research and Technology initiative is dedicated to researching and developing robust, high-field accelerator magnets for the future circular collider. As part of this initiative, the PSI team successfully designed, prototyped, and tested the first subscale stress-managed Nb3Sn common coil dipole magnet with enhanced training behavior. Following this accomplishment, a proposal was made for a stress-managed asymmetric common coil design for improved field quality, compatible with the requirements of accelerator magnets. This work follows the conceptual methodology proposed by PSI and details the electromagnetic and thermal design of a subscale asymmetric common coil magnet, equipped with a ferromagnetic yoke. The influence of the iron yoke on the magnet's field quality is analyzed and optimized according to the specified nominal current. A cooling strategy is proposed that involves cooling the windings using pipes carrying a fluid under forced flow, with the pipes in contact with the conductor. An alternative option, where the yoke is cooled to a higher temperature using a second fluid, is also considered. The magnet protection is analyzed considering an energy extraction system

Structural insights into copper and zinc binding to tau protein and the impact of metal binding on amyloid aggregation

Tau protein is a microtubule-associated protein central to the pathogenesis of Alzheimer's disease (AD) and other tauopathies. While metal ion homeostasis is disrupted in AD, the presence of copper and zinc in neurofibrillary tangles suggests a pathological role for metal–tau interactions. In this study, the metal binding properties of Tau441 were probed using a wide range of spectroscopic tools. Specifically, electron paramagnetic resonance, circular dichroism, nuclear magnetic resonance (NMR) and X-ray absorption spectroscopy (XAS) results point to a single high-affinity Cu2+ binding site within the microtubule-binding domain (MTBD), coordinated by the bis-His motif in R3 (His329/His330), possibly His299 and an oxygen-based ligand. This complex can be reduced resulting in a trigonal Cu+–Tau441 complex involving Cys322, His299 and a third ligand (likely Cys291 or His329/330), as characterized by XAS and NMR. NMR and XAS results indicate the presence of three Zn2+ binding sites: one high-affinity site in the MTBD involving His299, His330, Cys322 and Asp295, and two lower-affinity sites in the N-terminal region, coordinated predominantly by carboxylate and His residues. Moreover, the impact of Cu2+ and Zn2+ ions on the amyloid aggregation of full length Tau441 was evaluated using thioflavin T fluorescence, electrophoresis and transmission electron microscopy. Both metal ions significantly accelerate aggregation, promoting the formation of amyloid fibrils with distinct morphologies. Our study provides valuable structural insights into the copper and zinc binding sites in Tau441 that provide a rational basis to understand the impact of metal ions on amyloid fibril aggregation and morphology. The current study expands the bioinorganic facet of AD and other tauopathies, and it underscores the importance of metal–tau interactions as potential therapeutic targets in these neurodegenerative diseases

Escitalopram promotes recovery from hand paresis in cortical sensori-motor stroke: a randomized, double-blind, placebo-controlled longitudinal study

Background: Selective serotonin reuptake inhibitors (SSRIs) have been proposed to support post-stroke motor recovery, but evidence for domain-specific behavioral effects and associated neural mechanisms remains limited. This study examined whether early escitalopram administration influences recovery of within-hand motor dexterity following first-ever sensorimotor stroke affecting the pre- or postcentral gyrus. Methods: In a double-blind, placebo-controlled trial, participants were randomized to receive escitalopram or placebo during the first three months post-stroke. Motor dexterity was assessed behaviorally and with fMRI using an imitation-based task requiring observation and execution of grasp–regrasp movements. Measurements were acquired at baseline, three months, and nine months. Behavioral effects were analyzed using nonparametric statistics and a complementary permutation framework to assess robustness under small-sample conditions. Results: The escitalopram group showed greater improvement in Jebsen–Taylor Test subtest 1 from baseline to three months and in finger gaiting from three to nine months, with both effects supported by permutation testing. fMRI revealed increased activation in a left-hemispheric premotor–opercular–striatal network (OP6, BA44, anterior insula, posterior putamen) and in right premotor subarea 6v3 during motor execution in the escitalopram group. The placebo group, by contrast, exhibited increased activity in the left mediodorsal thalamus at nine months, consistent with compensatory recruitment. Conclusion: Although based on a small, highly specific cohort, the findings suggest that early escitalopram administration may facilitate recovery of fine motor control by supporting normalization of task-relevant cortical and subcortical networks. The placebo group’s delayed recovery pattern, characterized by thalamic overactivation, is compatible with compensatory executive engagement. Larger studies are needed to confirm these preliminary but mechanistically informative results

In situ diffuse reflectance infrared fourier-transform spectroscopy investigation of 1-methylcyclopropene adsorption in cobalt–formate metal–organic framework

Metal–organic frameworks (MOFs) find numerous applications due to their tunable adsorption/desorption properties. This work is focused on the spectroscopic investigation of the adsorption and release of ethylene (C2H4) and 1-methylcyclopropene (1-MCP)—natural plant growth hormone and its synthetic inhibitor—in the pores of Co3(HCOO)6 (Co-FA) MOF. Using in situ diffuse reflectance infrared Fourier-transform spectroscopy (DRIFTS), we have identified the molecular-level interactions between the adsorbed molecules and Co-FA pores, as evidenced by the characteristic shifts of the vibrational modes. The significant confinement of 1-MCP in Co-FA at room temperature was demonstrated, while moderate heating enabled its temperature-controlled release. In comparison, weaker but visible ethylene adsorption of C2H4 was also demonstrated, with significant desorption readily occurring at room temperature. Validation tests on bananas confirmed the superior performance of Co-FA over alternative MOFs, providing a link between molecular-level structure and practical applications

Reactors for fluid-solid reactions: fluidized bed reactors

The chapter on fluidized bed reactors describes the phenomena that occur when solid particles are fluidized in rising gas streams, and how these phenomena depend on the gas velocity, operating conditions and particle properties. The advantages and disadvantages of fluidized bed reactors and important applications of circulating and bubbling fluidized beds are presented. Other topics include the scaling up and modeling of fluidized bed reactors and some typical correlations for the mathematical description of the phenomena that occur. Finally, the peculiarities of using heat exchanger tubes in bubbling fluidized beds for exo- and endothermic reactions are discussed

When correlation matters: a practical guide to dealing with uncertainty in the case of data disaggregation

Correctly modeling the relationships between correlated, uncertain input data is crucial for producing accurate uncertainty estimates of model results. This requires both an uncertainty analysis that accounts for correlations and the appropriate communication of the results, so that other analysts can correctly interpret the reported uncertainties. However, neither is common practice in industrial ecology modeling. A typical case for correlated results is the disaggregation of a total value into uncertain shares, for which we present a practical yet robust approach to model the uncertainty. Our approach is based on two standard and two generalized Dirichlet distributions, and it uses the maximum entropy principle to choose minimally biased distribution parameters in the absence of specific known values. We discuss how correlation should be communicated to preserve accurate uncertainty information and provide examples to quantify the difference it makes to the results when the correlation is simplified or completely neglected. The proposed procedure will improve the accuracy of uncertainty quantification in Material Flow Analysis (e.g. where allocation coefficients split flows to sectors), Input Output Analysis (e.g. where aggregated environmental impact data has to be disaggregated to detailed economic sectors), and some instances in Life Cycle Assessment (e.g. where market shares are uncertain). Last but not least, to lower the technical barrier to applying these approaches, we provide easy-to-use Python and R packages which automate the approach

Observation and modeling of bound–bound and bound-free transitions in Cu₂

Laser-induced transitions from the perturbed (Formula presented) system to the (Formula presented) ground state of dicopper have been investigated experimentally and theoretically. Upon excitation of specific rotational levels, long progressions to vibrational levels are observed. Strong emissions are observed at low vibrational levels. Notably, spectra show significant line strength near and above the asymptotic atom dissociation limit. The latter feature is due to the Condon internal diffraction of bound-free transitions to the continuum region of the ground state. Based on the Rydberg–Klein–Rees potentials for the (Formula presented) states, eigenvalues and wave functions are obtained by solving the radial Schrödinger equation. Hence, frequencies of rovibrational transitions, Franck–Condon factors, and Einstein coefficients for spontaneous emissions are determined. The required transition dipole moment functions are obtained from high-level electronic structure calculations at the multi-reference configuration-interaction level of theory. Simulated line positions and relative intensities for transitions near and above the dissociation limit are in good agreement with the experiment. Furthermore, the feasibility of photoassociation experiments involving ultracold copper atoms is estimated by calculating the coupling rate between the colliding cold atoms and the excited (Formula presented) state

Structures of variants of Escherichia coli flavodiiron-type nitric oxide reductase reveal changes in the di-iron site

Flavodiiron proteins (FDPs) are NO and/or O2 reductases which contain a di-iron catalytic center. Interestingly, they exhibit different selectivities towards each one of these substrates, despite having the same ligands of the iron ions. Escherichia coli FDP is a selective NO reductase that protects this bacterium against nitric oxide by catalyzing two-electron reduction to the nontoxic N2O. Previously, based on kinetic studies, we explored the possible role of two amino acids located in the di-iron second coordination sphere, Lys53 and Tyr271, in modulation of the substrate selectivity of Entamoeba histolytica FDP, a selective O2 reductase. In this work, we replaced the structurally equivalent residues in E. coli FDP, Asp52 and Ser262, by those present in the O2-selective FDP and determined their crystal structures in both oxidized and reduced states. Furthermore, the molecular-substrate tunnels were experimentally identified using krypton pressurization of the crystals. The data obtained corroborated previous molecular-dynamics calculations on this FDP. The side chains of residues in both positions 52 and 262 of E. coli FDP variants and wild type are in the vicinity of the shorter intramolecular tunnel, which is suggested to be the exit route for the reaction products N2O and H2O. The E. coli FDP S262Y variant shows photoreduction of the di-iron center and partial loss of electron density in some of its coordinating ligands after X-ray exposure, and these effects are consistent with increased radiation sensitivity. The kinetic properties of the variants towards NO and O2 were not significantly different from the wild type, contrary to what was observed previously for E. histolytica FDP

Depolymerization-induced morphological transformation

Depolymerization offers a powerful route for the chemical recycling of vinyl polymers. However, current strategies focus almost exclusively on monomer recovery, which overlooks broader applications and opportunities. Herein, depolymerization-induced morphological transformation (DIMT) is introduced as a modular methodology to control the shape of sterically stabilized diblock copolymer nanoparticles and gain mechanistic insight into morphological transformations that occur during selective degradation of the methacrylic core-forming block. Notably, DIMT results in a sequential evolution in copolymer morphology from vesicles to worms to spheres. Transmission electron microscopy (TEM) and small-angle X-ray scattering (SAXS) studies enabled the construction of a predictive (pseudo)phase diagram. Furthermore, this new approach was also applied to the irreversible degelation of diblock copolymer worm gels, highlighting new opportunities to regulate material properties through depolymerization