Unified description of thermal and nonthermal laser-induced ultrafast structural changes in materials.

The ultrafast ionic dynamics in solids induced by intense femtosecond laser excitation are controlled by two fundamentally different yet interrelated phenomena. First, the substantial generation of hot electron-hole pairs by the laser pulse modifies the interatomic bonding strength and characteristics, inducing nonthermal ionic motion. Second, incoherent electron-ion collisions facilitate thermal equilibration between electrons and ions, achieving a uniform temperature on a picosecond timescale.

Magnetic colloidal single particles and dumbbells on a tilted washboard moiré pattern in a precessing external field.

We measure the dynamical behavior of colloidal singlets and dumbbells on an inclined magnetic moiré pattern, subject to a precessing external homogeneous magnetic field. At low external field strength single colloidal particles and dumbbells move everywhere on the pattern: at stronger external field strengths colloidal singlets and dumbbells are localized in generic locations. There are however nongeneric locations of flat channels that cross the moiré Wigner Seitz cell.

Casimir Effect in MEMS: Materials, Geometries, and Metrologies-A Review.

Casimir force densities, i.e., force per area, become very large if two solid material surfaces come closer together to each other than 10 nm.

Biological Rhythms Generated by a Single Activator-Repressor Loop with Inhomogeneity and Diffusion.

Common models of circadian rhythms are typically constructed as compartmental reactions of well-mixed biochemicals, incorporating a negative-feedback loop consisting of several intermediate reaction steps essentially required to produce oscillations. Spatial transport of each reactant is often represented as an extra compartmental reaction step. Contrary to this traditional understanding, in this Letter we demonstrate that a single activation-repression biochemical reaction pair is sufficient to generate sustained oscillations if the sites of both reactions are spatially separated and molecular transport is mediated by diffusion.

Topologically controlled synthesis of active colloidal bipeds.

Topological growth control allows to produce a narrow distribution of outgrown colloidal rods with defined and adjustable length. We use an external magnetic field to assemble paramagnetic colloidal spheres into colloidal rods of a chosen length. The rods reside above a metamorphic hexagonal magnetic pattern.

Optimal photoelectron circular dichroism of a model chiral system.

We optimize the internuclear geometry and electronic structure of a model chiral system to achieve a maximal photoelectron circular dichroism (PECD) in its one-photon ionization by circularly polarized light. The electronic structure calculations are performed by the single center method, while the optimization is done using quantum alchemy employing a Taylor series expansion. Thereby, the effect of bond lengths and uncompensated charge distributions on the chiral response of the model is investigated theoretically in some detail.

X-ray radiation damage cycle of solvated inorganic ions.

X-ray-induced damage is one of the key topics in radiation chemistry. Substantial damage is attributed to low-energy electrons and radicals emerging from direct inner-shell photoionization or produced by subsequent processes. We apply multi-electron coincidence spectroscopy to X-ray-irradiated aqueous solutions of inorganic ions to investigate the production of low-energy electrons (LEEs) in a predicted cascade of intermolecular charge- and energy-transfer processes, namely electron-transfer-mediated decay (ETMD) and interatomic/intermolecular Coulombic decay (ICD).

Transferability of atomic energies from alchemical decomposition.

We study alchemical atomic energy partitioning as a method to estimate atomization energies from atomic contributions, which are defined in physically rigorous and general ways through the use of the uniform electron gas as a joint reference. We analyze quantitatively the relation between atomic energies and their local environment using a dataset of 1325 organic molecules. The atomic energies are transferable across various molecules, enabling the prediction of atomization energies with a mean absolute error of 23 kcal/mol, comparable to simple statistical estimates but potentially more robust given their grounding in the physics-based decomposition scheme.

Polarized and Bright Telecom C-Band Single-Photon Source from InP-Based Quantum Dots Coupled to Elliptical Bragg Gratings.

Bright, polarized, and high-purity single-photon sources in telecom wavelengths are crucial components in long-distance quantum communication, optical quantum computation, and quantum networks. Semiconductor InAs/InP quantum dots (QDs) combined with photonic cavities provide a competitive path, leading to optimal single-photon sources in this range. Here, we demonstrate a bright and polarized single-photon source operating in the telecom C-band based on an elliptical Bragg grating (EBG) cavity.

Evolutionary Monte Carlo of QM Properties in Chemical Space: Electrolyte Design.

Optimizing a target function over the space of organic molecules is an important problem appearing in many fields of applied science but also a very difficult one due to the vast number of possible molecular systems. We propose an evolutionary Monte Carlo algorithm for solving such problems which is capable of straightforwardly tuning both exploration and exploitation characteristics of an optimization procedure while retaining favorable properties of genetic algorithms. The method, dubbed MOSAiCS (etropolis ptimization by ampling daptively n hemical pace), is tested on problems related to optimizing components of battery electrolytes, namely, minimizing solvation energy in water or maximizing dipole moment while enforcing a lower bound on the HOMO-LUMO gap; optimization was carried out over sets of molecular graphs inspired by QM9 and Electrolyte Genome Project (EGP) data sets.

Simultaneous and independent topological control of identical microparticles in non-periodic energy landscapes.

Topological protection ensures stability of information and particle transport against perturbations. We explore experimentally and computationally the topologically protected transport of magnetic colloids above spatially inhomogeneous magnetic patterns, revealing that transport complexity can be encoded in both the driving loop and the pattern. Complex patterns support intricate transport modes when the microparticles are subjected to simple time-periodic loops of a uniform magnetic field.

Combined Funnel, Concentrator, and Particle Valve Functional Element for Magnetophoretic Bead Transport Based on Engineered Magnetic Domain Patterns.

Controlled actuation of superparamagnetic beads (SPBs) within a microfluidic environment using tailored dynamic magnetic field landscapes (MFLs) is a potent approach for the realization of point-of-care diagnostics within Lab-on-a-chip (LOC) systems. Making use of an engineered magnetic domain pattern as the MFL source, a functional LOC-element with combined magnetophoretic "funnel", concentrator, and "valve" functions for micron-sized SPBs is presented. A parallel-stripe domain pattern design with periodically decreasing/increasing stripe lengths is fabricated in a topographically flat continuous exchange biased (EB) thin film system by ion bombardment induced magnetic patterning (IBMP).

The central role of density functional theory in the AI age.

Density functional theory (DFT) plays a pivotal role in chemical and materials science because of its relatively high predictive power, applicability, versatility, and computational efficiency. We review recent progress in machine learning (ML) model developments, which have relied heavily on DFT for synthetic data generation and for the design of model architectures. The general relevance of these developments is placed in a broader context for chemical and materials sciences.

Reduction Behavior of Anisyl-substituted P-Ferrocenyl Phospholes.

P-Ferrocenylphospholes with differing substituents in α-position have been synthesized and their identity and purity was confirmed using multinuclear NMR spectroscopy, MS, elemental analysis and single crystal X-ray diffraction. Furthermore, the redox properties have been explored with electrochemical measurements. Transferring the reduction to a preparative scale using lithium leads to reductive P-C bond cleavage furnishing the corresponding phospholide which has been transformed to P-tert-butyl substituted phosphole.

Electrochemistry and Stability of 1,1'-Ferrocene-Bisphosphonates.

Here, we investigate the electrochemical properties and stability of 1,1'-ferrocene-bisphosphonates in aqueous solutions. P NMR spectroscopy enables to track decomposition at extreme pH conditions revealing partial disintegration of the ferrocene core in air and under an argon atmosphere. ESI-MS indicates the decomposition pathways to be different in aqueous HPO, phosphate buffer, or NaOH solutions.

Influence of Chitosan and Grape Seed Extract on Thermal and Mechanical Properties of PLA Blends.

Blends based on polylactic acid (PLA), chitosan, and grape seed extract (GE) were prepared by extrusion and injection molding. The effect of chitosan (5% and 15% on PLA basis) and natural extract (1% on PLA basis) incorporated into the PLA host matrix was explored regarding the thermal and mechanical properties. GE showed antioxidant activity, as determined by the DPPH assay method.

Observation of a Long-lived Electronic Coherence Modulated by Vibrational Dynamics in Molecular Nd -Complexes at Room Temperature.

Temporally delayed, phase-locked coherent pairs of near IR femtosecond laser pulses were employed to study electronic coherences in molecular Nd -complexes at room temperature. Dissolved and solid complexes were studied under a confocal microscope set-up with fluorescence detection. The observed electronic coherence on a few hundred femtoseconds time scale is modulated by additional coherent wave packet dynamics, which we attribute mainly to be vibrational in nature.

Luminescent Properties of Phosphonate Ester-Supported Neodymium(III) Nitrate and Chloride Complexes.

This study examines the synthesis of two geminal bisphosphonate ester-supported Ln complexes [Ln()(NO)] (Ln = Nd (), La ()) and optical properties of the neodymium(III) complex. These results are compared to known mono-phosphonate ester-based Nd complexes [Nd(/)X] (X = NO, n = 1; Cl, n = 2) (-). The optical properties of Nd compounds are determined by micro-photoluminescence (µ-PL) spectroscopy which reveals three characteristic metal-centered emission bands in the NIR region related to transitions from F excited state.

Magnetic patterning of Co/Ni layered systems by plasma oxidation.

We studied the structural, chemical, and magnetic properties of Ti/Au/Co/Ni layered systems subjected to plasma oxidation. The process results in the formation of NiO at the expense of metallic Ni, as clearly evidenced by X-ray photoelectron spectroscopy, while not affecting the surface roughness and grain size of the Co/Ni bilayers. Since the decrease of the thickness of the Ni layer and the formation of NiO increase the perpendicular magnetic anisotropy, oxidation may be locally applied for magnetic patterning.

Three-dimensional close-to-substrate trajectories of magnetic microparticles in dynamically changing magnetic field landscapes.

The transport of magnetic particles (MPs) by dynamic magnetic field landscapes (MFLs) using magnetically patterned substrates is promising for the development of Lab-on-a-chip (LOC) systems. The inherent close-to-substrate MP motion is sensitive to changing particle-substrate interactions. Thus, the detection of a modified particle-substrate separation distance caused by surface binding of an analyte is expected to be a promising probe in analytics and diagnostics.

Effects of Mangosteen Peel Phenolic Compounds on Tilapia Skin Collagen-Based Mineralized Scaffold Properties.

A proper valorization of biological waste sources for an effective conversion into composites for tissue engineering is discussed in this study. Hence, the collagen and the phenolic compound applied in this investigation were extracted from waste sources, respectively, fish industry rejects and the peels of the mangosteen fruit. Porous scaffolds were prepared by combining both components at different compositions and mineralized at different temperatures to evaluate the modifications in the biomimetic formation of apatite.

Influence of blend ratio and mangosteen extract in chitosan/collagen gels and scaffolds: Rheological and release studies.

This study proposes the incorporation of mangosteen peel extract in chitosan and collagen gels and scaffolds, at different ratios, for fabricating materials with potential wound dressing applications. The extract addition increases the thermal stability of the collagen while decreasing to about one-fifth the swelling capability of its scaffolds. Oppositely, it enables chitosan and its blends to withstand high swelling percentages.

Asymmetrically Substituted Phospholes as Ligands for Coinage Metal Complexes.

A series of coinage metal complexes asymmetrically substituted 2,5-diaryl phosphole ligands is reported. Structure, identity, and purity of all obtained complexes were corroborated with state-of-the-art techniques (multinuclear NMR, mass spectrometry, elemental analysis, X-ray diffraction) in solution and solid state. All complexes obtained feature luminescence in solution as well as in the solid state.

Optical and Spin Properties of NV Center Ensembles in Diamond Nano-Pillars.

Nitrogen-vacancy (NV) color centers in diamond are excellent quantum sensors possessing high sensitivity and nano-scale spatial resolution. Their integration in photonic structures is often desired, since it leads to an increased photon emission and also allows the realization of solid-state quantum technology architectures. Here, we report the fabrication of diamond nano-pillars with diameters up to 1000 nm by electron beam lithography and inductively coupled plasma reactive ion etching in nitrogen-rich diamonds (type Ib) with [100] and [111] crystal orientations.