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Exploring “Fano resonance”-assisted trapping of core–shell hybrid nanoparticles under femtosecond pulsed excitation using the generalized Lorenz–Mie theory
The core–shell type structure of metal-dielectric nanoparticles has great applications in the fields of nanophotonics and biomedical sciences due to the plasmonic properties of metals and field enhancements at metal-dielectric interfaces. The present study reveals critical insights into the influence of these properties on the optical trapping of core–shell nanoparticles, investigated using generalized Lorenz-Mie theory. Specifically, the presence of Fano resonance is discussed based on the size contribution of the core and shell and its influence on the directionality of the scattering force. Furthermore, the effects of optical nonlinearity on the appearance of Fano resonance and trapping efficiency are explored under femtosecond pulsed excitation.
Photoelectron spectroscopy and formation mechanism of Ta2N3−: Activation of N2 by Ta2N−
This work investigated the reaction mechanism of N2 on Ta2N− via the photoelectron spectroscopy study of Ta2N3−, focusing on the activation of nitrogen molecules (N2) by Ta2N−. The vertical detachment energy of Ta2N3− was determined to be 2.22 eV from the experimental photoelectron spectrum. Charge and bond order analyses reveal significant electron transfer from Ta to N and strong Ta–N bonding, supporting the relative stability and reactivity of the cluster. Energy decomposition analysis and natural orbitals for chemical valence analysis show that orbital interactions, especially π- and σ-donations from Ta2N− to N2, dominate the activation process of N2. Substantial charge transfer occurs from the Ta2N− fragment to the N2 fragment, accompanied by noticeable polarization, which facilitates the breaking of the N≡N bond. The results highlight the importance of Ta–N bond coordination in stabilizing dissociated nitrogen atoms, making Ta2N− a potentially efficient species for N2 activation.
Investigating reactive oxygen species triggered damage to cell teichoic acid via molecular dynamics
In this study, we investigated the mechanisms by which reactive oxygen species (ROS) cause oxidative damage to wall teichoic acid (WTA) and lipoteichoic acid (LTA) in two bacterial species: Staphylococcus aureus and Streptococcus pneumoniae. Using molecular dynamics simulations, we found that ROS primarily induce structural damage through dehydrogenation reactions and the cleavage of C–C and C–O bonds. Notably, the teichoic acid (TA) from S. aureus was found to be more susceptible to damage compared to that of S. pneumoniae, which exhibited stronger antioxidant properties due to its ring structure and chemical modifications. The efficiency of damage increased with ROS concentration, following the order, O > O3 > OH, with a maximum of 22.22% C–C bond cleavage observed at the highest concentration. In addition, the patterns of damage in the TA of these two bacterial species were significantly different. In S. aureus, WTA damage was predominantly characterized by C–C and C–O bond cleavage in the repeating units, whereas LTA damage was primarily due to the cleavage of C–C bonds in the ring structure. In S. pneumoniae, damage to both WTA and LTA mainly occurred at the N-acetylglucosamine (GlcNAc) ring structure and the poly (RboP) site. This study offers new insights into the sterilizing effects of plasma.
Generalized spin in the variational determination of two-electron reduced density matrices within the doubly occupied configuration interaction framework
This work extends the variational determination of two-electron reduced density matrices to the generalized spin formulation within the doubly occupied configuration interaction treatment. We describe electronic states of N-electron systems by means of variational evaluation of the corresponding two-electron reduced density matrix elements, subject to determined N-representability conditions, arising from the restricted, unrestricted, and generalized spin approaches. The results are compared with those predicted by the counterpart treatments involving wave functions. We report potential energy curves for a series of hydrogen atom clusters with different geometries in the presence of an external uniform magnetic field. These results allow us to analyze and discuss crossings between potential energy curves involving transitions between electronic states of different spin multiplicities. The predictions provided by these methods have been contrasted with the results arising from the full configuration interaction procedure, confirming changes of ⟨Ŝ2⟩ and ⟨Ŝz⟩ expectation values.
Structure and adsorption properties of Cu–Au nanoparticles in harsh reactive environments
The reactivity of nanoparticles is governed by their surface composition, which tends to vary significantly under reactive conditions. In this study, the impacts of temperature and the presence of a CO or O2 atmosphere on the structures of Au79, Cu19Au60, Cu39Au40, Cu60Au19, and Cu79 nanoparticles were investigated using a combination of global optimization, machine learning interatomic potentials, and density functional theory. We find that increasing gold content weakens CO and O adsorption and limits oxygen-induced structural changes, while copper-rich particles undergo pronounced oxidation and reconstruction. Bader charge analysis shows that, in bare nanoalloys, Au withdraws electron density from Cu due to their electronegativity difference. In oxidized Cu–Au nanoalloys, the charge on Cu atoms depends on the number of O neighbors and can reach values typical of Cu2O (0.6 e) and CuO (1.1 e). On average, the Cu atoms exhibit positive effective Bader charges of ∼0.9 e in these nanoalloys. Our results indicate that models of Cu–Au catalysts under oxidizing conditions must incorporate the full ensemble of metallic and oxidized configurations rather than a single most probable structure to predict true catalytic activity.
Ion selectivity in uncharged tapered nanoslits through heterogeneous water polarization
We employ molecular dynamics simulations to investigate ion and water transport driven by an electric field through quasi-two-dimensional nanoslits with a tapered geometry. Despite the absence of surface charge on the (non-polarizable) channel walls and the associated electric double layer, we do observe robust ion selectivity. This selectivity favors the transport of cations from base to tip when the electric field is directed from base to tip, and anions from base to tip when the field direction is reversed. In addition, we observe a corresponding electro-osmotic water flow from base to tip, regardless of the electric field direction. Intriguingly, ion selectivity and electro-osmotic flow are conventionally associated with surface charge and electric double layers. Here, however, we uncover a novel mechanism for these phenomena in uncharged tapered nanoslits, where ion selectivity arises from the divergence of the heterogeneous water polarization.
Dynamic correlations in a polar fluid: Confronting stochastic density functional theory to simulations
Understanding the dynamic behavior of polar fluids is essential for modeling complex systems such as electrolytes and biological media. In this work, we develop and apply a stochastic density functional theory (SDFT) framework to describe the polarization dynamics in the Stockmayer fluid, a prototypical model of dipolar liquids consisting of Lennard-Jones particles with embedded point dipoles. Starting from the overdamped Langevin dynamics of dipolar particles, we derive analytical expressions for the intermediate scattering functions and dynamic structure factors of the longitudinal and transverse components of the polarization field, within linearized SDFT. To assess the theory’s validity, we compare its predictions with results from Brownian Dynamics simulations of the Stockmayer fluid. We find that SDFT captures the longitudinal polarization fluctuations accurately, while transverse fluctuations are underestimated due to the neglect of dipolar correlations. By incorporating the Kirkwood factor into a modified SDFT, we recover quantitative agreement for both components across a range of dipole strengths. This study highlights the utility of SDFT as a coarse-grained description of polar fluid dynamics and provides insights into the role of collective effects in polarization relaxation.
Modeling gonorrhea and HIV coinfection with predictive analytics for disability and mortality risks
Optimizing toe joint stiffness to improve human-like walking
The cholinergic drug galantamine ameliorates acute and subacute peripheral and brain manifestations of acute respiratory distress syndrome in mice
Exact extraction of stress intensity factors via enriched numerical manifold method with composite patches
Gene cloning of S100β and NGF and localization of their expression in the small intestine of broilers of various ages
Genetic susceptibility to oral and atherosclerotic cardiovascular diseases based on dental and heart SCORE studies
Abstract Periodontal disease and dental caries are two oral conditions that have been associated with atherosclerotic cardiovascular disease (ASCVD). However, it is unclear if one of the key mechanisms involved in this association could be a shared genetic susceptibility. The goal of this study was to explore whether there is an intersection of genetic loci among individuals with comprehensive oral examinations and subclinical ASCVD screenings. We leveraged data from oral and medical examinations obtained from the Dental and Heart Strategies Concentrating on Risk Evaluation (Dental/Heart SCORE) projects. Genome-wide association studies (GWASs) were performed independently in 552 participants (aged 45–75 years). The decayed, missing, or filled teeth index (DMFT) and periodontal disease indices were used to reflect oral conditions; coronary artery calcium scores (CAC) and carotid intima media thickness (CIMT) were analyzed as subclinical ASCVD traits. Single nucleotide variant (SNV) associations with oral and ASCVD traits were found; however, there were only a few regions of suggestive genetic loci overlap between these conditions. The most robust associations found for each phenotype are as follows: DMFT with rs79198416 (near CDC73/KCNT2; p = 7.57E-07), periodontal disease with rs73870587 (DIPK2A, p = 7.38E-08); CIMT with rs113152669 (LRP1B p = 4.07E-07), and CAC with rs76676138 (CNTNAP2; p = 2.47E-19). Although genetic associations were identified for each of the phenotypes of interest in the GWASs, there were no regions of shared genetic loci that significantly intersected across phenotypes. Thus, our results suggest that incorporation of environmental, behavioral, microbiome-related factors, and larger sample sizes, are warranted in future studies between oral and cardiovascular health.
Metal pattern-based planar sub-THz filter in coplanar waveguide on optically transparent substrate
Abstract The sub-terahertz and terahertz frequency bands (0.1–10 THz) hold immense potential for revolutionizing diverse fields, ranging from advanced telecommunications to biomedical diagnostics and structural biology. Despite the rapidly growing interest in these frequencies, there is a significant gap in the development of compact, high-performance sub-terahertz devices on optically transparent substrates. Such substrates are crucial for integration with optical microscopy and spectroscopy techniques, enabling applications in biophysics and material sciences. To address this technology gap, this paper presents the design, fabrication, and measurement of a compact band-stop filter unit operating in the sub-terahertz F-band (90–140 GHz) on an optically transparent substrate. The unit utilizes a $$\lambda$$ /4 open-end folded stub resonator structure integrated within a coplanar waveguide. Different coupling variants between the stub and coplanar waveguide were analyzed using frequency domain simulations. The device is compatible with advanced optical microscopy techniques since it is implemented on an optically transparent quartz glass substrate. This feature enables future applications in spectroscopy or biophysics thanks to straightforward integrability with microfluidics. The unit can be cascaded into a higher-order filter to enhance its performance.
The impacts of nonnegative doctor portrayals on public evaluations and professional attractiveness in medicine
Abstract This study explores the impacts of four common nonnegative media portrayals of doctors (i.e., science experts, angels in white, white-coated warriors, and vulnerable groups) on public evaluations (i.e.,stereotype content, emotional responses, and trust) and professional attractiveness (i.e.,willingness to marry or encourage child to become a doctor). Study 1 (N = 216) featured a between-participants design, revealing that the warrior and angel portrayals both led to more favourable ratings for warmth, competence, morality, admiration, reduced contempt, and trust than were observed in the control group. The warrior portrayal consistently received the highest scores in most dimensions, including professional attractiveness. The expert portrayal notably enhanced competence evaluations and reduced contempt, whereas the vulnerable portrayal elicited higher levels of sympathy but was associated with the lowest scores in most other dimensions. Study 2 (N = 320) featured a 3 (portrayal type; within-participants) × 6 (sequence; between-participants) mixed design, revealing that presentation order moderated the effects of such portrayals. The most effective sequence, angel–expert–vulnerable, elicited the highest overall evaluations, whereas the angel–vulnerable–expert sequence was least effective. These findings suggest that not only content but also sequence of portrayals can shape public attitudes towards doctors, thus highlighting relevant implications for health communication and media strategies.