Diffusion Generative Models for Designing Efficient Singlet Fission Dimers.

Diffusion generative models, a class of machine learning techniques, have shown remarkable promise in materials science and chemistry by enabling the precise generation of complex molecular structures. In this article, we propose a novel application of diffusion generative models for stabilizing reactive molecular structures identified through quantum mechanical screening. Specifically, we focus on the design challenge presented by singlet fission (SF), a phenomenon crucial for advancing solar cell efficiency beyond theoretical limits.

Phase Characterization and Bioactivity Evaluation of Nucleic Acid-Encapsulated Biomimetically Mineralized ZIF-8.

Metal-organic frameworks (MOFs) provide diverse applications across a wide range of scientific disciplines, including drug/nucleic acid (NA) delivery. In the subclass of MOFs, zeolitic imidazolate framework-8 (ZIF-8) is well regarded due to its exceptional physicochemical properties. Biomolecules can be encapsulated and released under precise conditions within ZIF, making it an important material for materials science and biomedical applications.

Photoswitch dissociation from a G protein-coupled receptor resolved by time-resolved serial crystallography.

G protein-coupled receptors (GPCRs) are the largest family of cell surface receptors in humans. The binding and dissociation of ligands tunes the inherent conformational flexibility of these important drug targets towards distinct functional states. Here we show how to trigger and resolve protein-ligand interaction dynamics within the human adenosine A receptor.

Nanodots of Transition Metal Sulfides, Carbonates, and Oxides Obtained Through Spontaneous Co-Precipitation with Silica.

The controlled formation and stabilization of nanoparticles is of fundamental relevance for materials science and key to many modern technologies. Common synthetic strategies to arrest growth at small sizes and prevent undesired particle agglomeration often rely on the use of organic additives and require non-aqueous media and/or high temperatures, all of which appear critical with respect to production costs, safety, and sustainability. In the present work, we demonstrate a simple one-pot process in water under ambient conditions that can produce particles of various transition metal carbonates and sulfides with sizes of only a few nanometers embedded in a silica shell, similar to particles derived from more elaborate synthesis routes, like the sol-gel process.

UV Hyperspectral Imaging with Xenon and Deuterium Light Sources: Integrating PCA and Neural Networks for Analysis of Different Raw Cotton Types.

Ultraviolet (UV) hyperspectral imaging shows significant promise for the classification and quality assessment of raw cotton, a key material in the textile industry. This study evaluates the efficacy of UV hyperspectral imaging (225-408 nm) using two different light sources: xenon arc (XBO) and deuterium lamps, in comparison to NIR hyperspectral imaging. The aim is to determine which light source provides better differentiation between cotton types in UV hyperspectral imaging, as each interacts differently with the materials, potentially affecting imaging quality and classification accuracy.

is implicated in central nervous system, orofacial and maxillofacial anomalies.

Background: Previous studies in mouse, and zebrafish embryos show strong expression in progenitor cells of neuronal and neural crest tissues suggesting its involvement in neural crest specification. However, the role of human transcription factor activator protein 2 ( in human embryonic central nervous system (CNS), orofacial and maxillofacial development is unknown.

Methods: Through a collaborative work, exome survey was performed in families with congenital CNS, orofacial and maxillofacial anomalies.

MS -Pushing the Limits for Biomolecular Mass Spectrometry.

Electrospray mass spectrometry has become indispensable in many disciplines including the classic "omics" techniques such as proteomics or lipidomics, as well as other life science applications in molecular, cellular, and structural biology. However, a limiting factor that often arises for the detection of biomolecular analytes is their poor ionization efficiency in the ion source. Here, we present an add-on device for the electrospray source, termed MS (MS Spectral Impurity Eliminator & Value Enhancer), which is placed between the electrospray needle and the cone of the mass spectrometer.

Wavelength-Dependent Dynamic Behavior in Thiol-Ene Networks Based on Disulfide Exchange.

While latent catalysts have become a well-established strategy for locally and temporally controlling bond exchange reactions in dynamic polymer networks, there is a lack of inherently tailorable systems. Herein, we introduce a thiol-ene network based on disulfide exchange that alters its dynamic properties as a function of the color of light used during the curing reaction. For this purpose, selected allyl-bearing disulfides are synthesized, which are transparent at 450 nm but undergo disulfide scission upon 365 nm light irradiation, as confirmed by UV-vis and EPR measurements.

Continuous Tuning of Intersystem Crossing Times in Rose Bengal Water/Methanol Solutions.

We use femtosecond transient broadband absorption spectroscopy (TAS) to characterize Rose Bengal in water/methanol solutions and reveal a continuous tunability of intersystem crossing (ISC) times by changing the mole fraction of the solvents. We find that the transients of excited state absorptions (ESAs) in Rose Bengal at ∼430 nm can be attributed to transitions from the singlet state S, with decay times of 74 ps via ISC in pure water and up to 405 ps in pure methanol. TA measurements at near-infrared wavelengths, on the other hand, reveal the rise of an ESA at ∼1080 nm from the triplet state T with time constants of 68 and 491 ps in pure water and methanol, respectively, strongly supporting the associated UV-vis TAS data.

Magnetically Responsive Enzyme and Hydrogen-Bonded Organic Framework Biocomposites for Biosensing.

The one-pot synthesis of multicomponent hydrogen-bonded organic framework (HOF) biocomposites is reported. The co-immoblization of enzymes and magnetic nanoparticles (MNPs) into the HOF crystals yielded biocatalysts (MNPs-enzyme@BioHOF-1) with dynamic localization properties. Using a permanent magnet, it is possible to separate the MNPs-enzyme@BioHOF-1 particles from a solution.

Modeling early phenotypes of Parkinson's disease by age-induced midbrain-striatum assembloids.

Parkinson's disease, an aging-associated neurodegenerative disorder, is characterised by nigrostriatal pathway dysfunction caused by the gradual loss of dopaminergic neurons in the substantia nigra pars compacta of the midbrain. Human in vitro models are enabling the study of the dopaminergic neurons' loss, but not the dysregulation within the dopaminergic network in the nigrostriatal pathway. Additionally, these models do not incorporate aging characteristics which potentially contribute to the development of Parkinson's disease.

Sub-millielectronvolt Line Widths in Polarized Low-Temperature Photoluminescence of 2D PbS Nanoplatelets.

Colloidal semiconductor nanocrystals are promising materials for classical and quantum light sources due to their efficient photoluminescence (PL) and versatile chemistry. While visible emitters are well-established, excellent (near-infrared) sources are still being pursued. We present the first comprehensive analysis of low-temperature PL from two-dimensional (2D) PbS nanoplatelets (NPLs).

What is the Exchange Repulsion Energy? Insight by Partitioning into Physically Meaningful Contributions.

It is shown that the exchange repulsion energy, E, can be rationalized by partitioning the respective energy expression for two systems with Hartree-Fock orbitals into physically meaningful contributions. A division of E into a positive kinetic and a negative potential part is possible, but these contributions correlate only poorly with the actual exchange repulsion energy. A more meaningful partitioning is derived, where all kinetic energy contributions are collected in a term that vanishes for exact Hartree-Fock orbitals due to their stationarity conditions.

Protein-Ligand Interaction Energies from Quantum-Chemical Fragmentation Methods: Upgrading the MFCC-Scheme with Many-Body Contributions.

Quantum-chemical fragmentation methods offer an attractive approach for the accurate calculation of protein-ligand interaction energies. While the molecular fractionation with conjugate caps (MFCC) scheme offers a rather straightforward approach for this purpose, its accuracy is often not sufficient. Here, we upgrade the MFCC scheme for the calculation of protein-ligand interactions by including many-body contributions.

Long-Term Single-Molecule Tracking in Living Cells using Weak-Affinity Protein Labeling.

Single-particle tracking (SPT) has become a powerful tool to monitor the dynamics of membrane proteins in living cells. However, permanent labeling strategies for SPT suffer from photobleaching as a major limitation, restricting observation times, and obstructing the study of long-term cellular processes within single living cells. Here, we use exchangeable HaloTag Ligands (xHTLs) as an easy-to-apply labeling approach for live-cell SPT and demonstrate extended observation times of individual living cells of up to 30 minutes.

Threshold photoelectron spectroscopy of organosulfur radicals.

We report vibrationally resolved threshold photoelectron spectra of several sulfur-containing reactive intermediates. This includes the organosulfur radicals CHS, CHS, CHSH, CHS, and SH, which are relevant in atmospheric chemistry and in astrochemical settings. Due to the high reactivity, the radicals were prepared pyrolysis of (CH)S.

Kinetic Basis for the Design of Azobenzene-Based Photoswitchable A Adenosine Receptor Ligands.

Photoisomerization of ligands is a key process in the field of photopharmacology. Thus, the kinetics and efficiency of this initial photoreaction are of great importance but can be influenced by the molecular environment of the binding pocket and the resulting confinement of the reaction pathway. In this study, we investigated the photoisomerization of an azobenzene derivative of the anti-Parkinson's drug istradefylline.

A Detailed View on the (Re)isomerization Dynamics in Microbial Rhodopsins Using Complementary Near-UV and IR Readouts.

Isomerization is a key process in many (bio)chemical systems. In microbial rhodopsins, the photoinduced isomerization of the all-trans retinal to the 13-cis isomer initiates a cascade of structural changes of the protein. The interplay between these changes and the thermal relaxation of the isomerized retinal is one of the crucial determinants for rhodopsin functionality.

Three-Dimensional (3D) Surface-Enhanced Raman Spectroscopy (SERS) Substrates for Sensing Low-Concentration Molecules in Solution.

The use of surface-enhanced Raman spectroscopy (SERS) in liquid solutions has always been challenging due to signal fluctuations, inconsistent data, and difficulties in obtaining reliable results, especially at very low analyte concentrations. In our study, we introduce a new method using a three-dimensional (3D) SERS substrate made of silica microparticles (SMPs) with attached plasmonic nanoparticles (NPs). These SMPs were placed in low-concentration analyte solutions for SERS analysis.

Impurities in Arylboronic Esters Induce Persistent Afterglow.

Several recent reports suggest that arylboronic esters can exhibit room temperature phosphorescence (RTP), an optical property that is desirable for applications in security printing, oxygen sensing, and bioimaging. These findings challenged the fundamental notion that heavy elements or changes in orbital symmetry were required for intersystem crossing to occur in organic compounds. As we had not observed long afterglow in the many arylboronic esters we had synthesized over many years, we suspected that the RTP observed in these systems had a simpler explanation: the materials reported were impure.

Bismuth Bound to Transition Metals: Visible-Light-Induced Olefin Coordination, Reductive Elimination, and Oxidative Addition.

A series of dibenzobismepinyl (CHBi) substituted transition metal complexes of the type [(CHBi)M(CO)(L)] (M=Mn, Co, Fe) was prepared in salt elimination reactions from a halobismepine and sodium metallates. Irradiation of these complexes with visible light has been investigated, aiming at the elimination of one carbonyl ligand and the concomitant coordination of the bismepine's olefin moiety to the transition metal center. The resulting complexes of the type [{κC,κBi-(CH)Bi}M(CO)(L)] (M=Co, Fe) have been isolated and fully characterized.

Single-molecule imaging and molecular dynamics simulations reveal early activation of the MET receptor in cells.

Embedding of cell-surface receptors into a membrane defines their dynamics but also complicates experimental characterization of their signaling complexes. The hepatocyte growth factor receptor MET is a receptor tyrosine kinase involved in cellular processes such as proliferation, migration, and survival. It is also targeted by the pathogen Listeria monocytogenes, whose invasion protein, internalin B (InlB), binds to MET, forming a signaling dimer that triggers pathogen internalization.