UNPs as HEDP simulators

Bacterial infections continue to drive the need for more effective and rapid methods for bacterial analysis. To address this, magnetic nanoparticles (MNPs) have emerged as promising tools, especially when their surfaces are modified with bacteria binders. The bis-zinc–dipicolylamine (Zn–DPA) complex is known for its broad affinity to bacteria. We have synthesized MNPs via a thermal decomposition method, encapsulated them in silica, modified their surface with Zn–DPA, and tested their ability to remove bacteria. The MNPs retain their superparamagnetic properties and crystallite structure after being encapsulated. The MNPs coated with silica and Zn–DPA effectively bind and remove both Gram-positive and Gram-negative bacteria from bacterial suspensions in both PBS buffer and red blood cell suspension. The capture efficiency (CE) of bacteria is high, >0.95 for both concentrated (1 × 108 CFU) and dilute (1 × 103 CFU) suspensions of Gram-positive and Gram-negative bacteria in PBS. The bacterial capture efficiency in red blood cell suspension with 50% hematocrit ranges is high (CE > 0.95) for both concentrated and dilute suspensions of S. aureus but lower for concentrated (CE = 0.30) and dilute (CE = 0.15) suspensions of E. coli. The Zn–DPA coated MNPs have promising binding efficiencies for a broad-spectrum of bacteria within a short period of time, potentially leading to applications in diagnostic devices for both medical and industrial uses.

We present ground-based multiband light curves of the AGN Mrk 509, NGC 4151, and NGC 4593 obtained contemporaneously with Swift monitoring. We measure cross-correlation lags relative to Swift UVW2 (1928 Å) and test the standard prediction for disc reprocessing, which assumes a geometrically thin optically thick accretion disc where continuum interband delays follow the relation ⁠. For Mrk 509 the 273-d Swift campaign gives well-defined lags that increase with wavelength as ⁠, steeper than the thin-disc prediction, and the optical lags are a factor of  longer than expected for a simple disc-reprocessing model. This ‘disc-size discrepancy’ as well as excess lags in the u and r bands (which include the Balmer continuum and H ⁠, respectively) suggest a mix of short lags from the disc and longer lags from nebular continuum originating in the broad-line region. The shorter Swift campaigns, 69 d on NGC 4151 and 22 d on NGC 4593, yield less well-defined shorter lags  d. The NGC 4593 lags are consistent with  but with uncertainties too large for a strong test. For NGC 4151 the Swift lags match ⁠, with a small U-band excess, but the ground-based lags in the r, i, and z bands are significantly shorter than the B and g lags, and also shorter than expected from the thin-disc prediction. The interpretation of this unusual lag spectrum is unclear. Overall these results indicate significant diversity in the  relation across the optical/UV/NIR, which differs from the more homogeneous behaviour seen in the Swift bands.

Computational enzyme design remains a powerful yet imperfect tool for optimizing biocatalysts, especially when targeting non-natural substrates. Using design tools we investigated Pseudomonas aeruginosa LipA, a lipase with a flexible lid domain crucial for substrate binding and turnover, aiming to enhance its hydrolysis of the industrially relevant substrate Roche ester. We generated an initial set of single-point mutations based on structural proximity to the active site and evaluated their effects using a computational pipeline integrating molecular dynamics (MD) simulations, density functional theory (DFT) calculations, and ensemble-based energy scoring. While we identified several active variants, attempts to rank them by activity using structural features, such as hydrogen bond formation or residue flexibility, failed. Deep learning models, applied post hoc for structural analysis via AlphaFold3, produced nearly identical active site geometries across variants, irrespective of activity. Reaction pathway analysis revealed energy barriers varying by 5–15 kcal/mol depending on substrate conformation, with the nucleophile addition step consistently rate-limiting. However, these small energetic shifts, likely critical for incremental activity changes, were indistinguishable by current computational or deep learning methods. Our results highlight the limitations of existing approaches in resolving subtle functional differences and underscore the need for improved benchmarks, reactive force fields, and more sensitive ranking metrics. Advancing these areas will be essential for designing enzymes with gradual, evolution-like activity improvements and for bridging the gap between structural prediction and catalytic function.

We provide experimental evidence for the absence of a magnetic moment in bulk RuO₂, a candidate altermagnetic material, by using a combination of Mössbauer spectroscopy, nuclear forward scattering, inelastic X-ray and neutron scattering, and density functional theory calculations. Using complementary Mössbauer and nuclear forward scattering, we determine the Ru magnetic hyperfine splitting to be negligible. Inelastic X-ray and neutron scattering-derived lattice dynamics of RuO₂ are compared to density functional theory calculations of varying flavors. Comparisons among theory with experiments indicate that electronic correlations, rather than magnetic order, are key in describing the lattice dynamics.

The glockenspiel is a bright, resonant percussion instrument with a series of simple bars mounted next to each other in a frame. Its acoustic radiation remains underexplored, particularly in its full instrument configuration. This study investigates the acoustic radiation and vibrational behavior of a glockenspiel bar in different mounting conditions. Directivity measurements and the scanning laser Doppler vibrometer were used to compare a single bar in free-free, baffled, and full-instrument configurations. The results show that the mounting significantly alters radiation patterns of the bar, particularly at higher modes. Torsional modes exhibited greater deviation from free-free predictions than bending modes, especially in the full-instrument case. The findings highlight the importance of considering frame and structural interactions in modeling glockenspiel vibration and radiation.

Modern superconducting radio frequency (SRF) applications demand precise control over material properties across multiple length scales—from microscopic composition, to mesoscopic defect structures, to macroscopic cavity geometry. We present a time-dependent Ginzburg-Landau (TDGL) framework that incorporates spatially varying parameters derived from experimental measurements and ab initio calculations, enabling realistic, sample-specific simulations. As a demonstration, we model Sn-deficient islands in Nb₃Sn and calculate the field at which vortex nucleation first occurs for various defect configurations. These thresholds serve as a predictive tool for identifying defects likely to degrade SRF cavity performance. We then simulate the resulting dissipation and show how aggregate contributions from multiple small defects can reproduce trends consistent with high-field 𝑄-slope behavior observed experimentally. Our results offer a pathway for connecting microscopic defect properties to macroscopic SRF performance using a computationally efficient mesoscopic model.