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Negative ion formation from water molecule following absorption of vacuum ultraviolet light
Negative ion formations through ion-pair photodissociation or dissociative photoionization of H2O and D2O have been investigated by using an imaging technique in conjunction with the pulsed synchrotron light in the photon energy range between 17 and 41 eV. Cross sections for the formations of H−/D−, O−, and OH−/OD− were measured as a function of the photon energy. The large isotope effect observed in the previous mass spectroscopic study [Hunniford et al., J. Phys. B: At., Mol. Opt. Phys. 40, 1225 (2007)] were only partially reproduced in the present study. The kinetic energies of O− and H−/D− vary with increasing photon energy, which have been analyzed based on the kinematics. Through the analysis, the mechanisms of the two-body or three-body ion-pair photodissociations have been revealed. It has also been found that the axial recoil approximation breaks in the three-body ion-pair dissociation, forming O−.
Electron scattering from prebiotic ethylene glycol: An R-matrix study
Ethylene glycol is a prebiotically relevant complex organic molecule detected in interstellar and cometary environments, yet quantitative low-energy electron–ethylene glycol scattering data remain limited for astrochemical modeling. This work presents an R-matrix study of low-energy electron collisions with ethylene glycol over a 0–12 eV energy range, using static exchange (SE), static exchange plus polarization (SEP), and configuration interaction (CI) models with 6-311G* and cc-pVTZ basis sets. We compute elastic, excitation, and differential cross-sections within a close-coupling framework. The dataset offers benchmark inputs for astrochemical models, supporting interpretation of ethylene glycol abundances in space and refining constraints on electron-induced prebiotic pathways.
Reduced dynamical maps in finite temperature vibronic coupling models via Choi matrices: Numerical methods and applications
We present a streamlined implementation of a computational framework for constructing and analyzing reduced dynamical maps for complex system–bath models at finite temperature. The methodology is based on three established ingredients of quantum dynamics: the Choi–Jamiołkowski isomorphism for the representation of quantum channels, thermofield (TFD) purification of thermal environments, and tensor-train (TT) propagation of the resulting enlarged pure state. The reduced map is obtained from a single unitary propagation in a thermofield-doubled Hilbert space and represented in matrix form through the Choi–Jamiołkowski isomorphism. The TFD evolution is implemented in the TT representation, enabling efficient propagation of high-dimensional purified thermal states. We illustrate the methodology for exciton transfer in the Fenna–Matthews–Olson complex with site-dependent structured spectral densities represented by discretized bosonic environments. The resulting maps are used to analyze decoherence, relaxation, and finite-memory effects, and to assess the crossover to an effectively time-local description. The proposed approach provides a route to compute reduced propagators and to post-process them into memory kernels, transfer tensors, and effective kinetic rate descriptions for complex molecular systems.
Investigation of Coulomb scattering centers using a substrate bias effect in <i>n</i> -channel metal–oxide–semiconductor field-effect transistors with AlSiO/AlN/ <i>p</i> -type GaN gate structures
Electron scattering factors are analyzed for GaN metal–oxide–semiconductor field-effect transistors (MOSFETs) using gate-biased Hall-effect measurements. The fabricated MOSFETs and Hall devices have AlSiO/AlN/p-type GaN gate structures formed on bottom p+/n+ GaN junctions. Because the capacitance of the bottom p+/n+ junction is much greater than the gate capacitance, the p-type body layer and the substrate electrode are short-circuited. Thus, the body potential is controlled by the substrate bias (Vsub). To investigate Coulomb scattering due to Mg dopants, MOSFETs with Mg-doped and undoped body layers are prepared. Comparing the sheet carrier densities Ns estimated from a capacitance–voltage curve and the Hall effect reveals that almost all electrons contribute to conduction in both channels. In the plot of Hall-effect mobility as a function of Ns, Coulomb scattering components are proportional to Nsγ. If Coulomb scattering is mainly caused by bulk impurities, γ should be unity. However, γ &lt; 1 is obtained, indicating the existence of Coulomb scattering centers other than Mg atoms. The effective electric field perpendicular to the channels is essentially different between both channels, resulting in differences in the scattering magnitudes. Vsub allows control of the effective channel field independent of the gate bias. The effective channel field in the Mg-doped channel at Vsub = 0 V is almost equivalent to that in the undoped channel at −40 V. Then, the Hall-effect mobilities are almost equal. We conclude that Coulomb scattering centers are mainly located near the interface between the gate insulator and the channel.
Cation/anion and monovalent/divalent selectivity in negatively charged nanopores: The effect of modeling the charged surface groups
The anomalous mole fraction effect (AMFE) is widely regarded as a hallmark of calcium vs monovalent ion selectivity in negatively charged pores. While AMFE is well understood in highly cation-selective narrow ion channels, its microscopic origin in wide synthetic nanopores, where anions may also contribute to transport, remains less clear. Here, we use a reduced Nernst–Planck + Local Equilibrium Monte Carlo framework to study ionic transport in a negatively charged polyethylene terephthalate nanopore, with particular emphasis on how the modeling of surface carboxyl (COO−) groups influences charge inversion, ionic currents, and AMFE. We systematically compare fixed point-charge models and explicit-particle representations of surface oxygens and identify two controlling parameters: the distance of closest approach (DCA) between ionic charges and pore charges and grid spacing that modulates localization (while keeping average surface charge constant). By fitting pore diffusion coefficients to three experimental conductance points, we reproduce the entire experimental AMFE curve as well as anion leakage in CaCl2 seen in experiments and molecular dynamics simulations. Remarkably, vastly different microscopic models of the surface groups yield indistinguishable device-level conductance curves when the DCA and grid spacing are matched, despite substantial differences in local Ca2+ concentration profiles. Our results demonstrate that AMFE in wide nanopores is governed by the strong adsorption of divalent cations to pore charges compared to monovalent cations, the resulting changes in ionic mobilities, and increased anion leakage with increasing calcium mole fraction. In wide pores, therefore, selectivity between monovalent and divalent cations is modulated by cation vs anion selectivity.
Halide-dependent photoelectrical response and charge transport in EVA-embedded Cs2TiClxBr6−x perovskite thin films
Lead-free titanium halide perovskites with the formula Cs2TiClxBr6−x were integrated into an ethylene–vinyl acetate (EVA) matrix to form hybrid perovskite thin films with tunable optoelectronic properties. Importantly, this work goes beyond compositional tuning by demonstrating that the polymer–perovskite hybrid architecture actively governs interfacial charge transport and polarization phenomena. Structural and optical characterization confirmed the formation of vacancy-ordered double perovskites with visible-light absorption and photoluminescence features associated with defect-mediated electronic relaxation. The electrical and photoinduced responses of the composites were investigated using electrochemical impedance spectroscopy with symmetric fluorine-doped tin oxide (FTO)│EVA│FTO configurations. Upon illumination, the films exhibited a marked decrease in impedance, revealing the halide-dependent modulation of charge transport, interfacial polarization, and pseudocapacitive behavior. Mixed-halide compositions displayed improved electrical uniformity and reduced transport resistance compared to pristine EVA, indicating enhanced photoinduced charge dynamics. Hirshfeld surface analysis was employed as a structural descriptor to quantify halide surface exposure, thereby linking composition-dependent electronic localization to the observed photoelectrical response. As a functional demonstration of these charge dynamics, the hybrid films were also evaluated under photocatalytic conditions, where light-driven formate and hydrogen generation corroborated the effective charge separation inferred from impedance measurements.
Effect of ensemble averaging on Green–Kubo estimation of short-time stress relaxation modulus in all-atom molecular dynamics simulations of an unentangled polymer melt
Response to “Comment on ‘Determining angle of arrival of radio frequency fields using subwavelength, amplitude-only measurements of standing waves in a Rydberg atom sensor”’ [J. Appl. Phys. 138, 114402 (2025)]
Analysis of factors influencing self-Q-switching of erbium-doped fiber
Self-Q-switched erbium-doped fiber (EDF) lasers combine a high damage threshold, a compact, miniaturizable structure, and the ability to generate stable Q-switched pulses. However, in communication systems, the self-Q-switching behavior of gain fibers can cause optical damage. To investigate these issues, we investigated high-gain erbium-doped fiber used as a saturable absorber (EDF-SA). Experiments show that, within a specific length range, increasing the EDF-SA length significantly enhances Q-switching performance: It increases the maximum single-pulse energy and reduces pulse width—improvements that are important for high-performance all-fiber Q-switched lasers. We attribute this improvement to the greater pump-light absorption efficiency of longer absorbers. Further experiments show that, for a fixed EDF length, peak power and single-pulse energy increase with pump power up to a point and then decline. This reversal results from amplified spontaneous emission at high pump powers, which depletes stored energy before Q-switching occurs. Moreover, inserting a non-Q-switched EDF segment effectively suppresses self-Q-switching in high-gain EDFs, providing a practical means to protect communication devices from optical damage. We attribute the ability of EDFs to produce Q-switched pulses primarily to ion-pair interactions and fast carrier recovery dynamics rather than to the saturable-absorption curve alone. Finally, based on measured data, we hypothesize that the observed self-pulsing originates from relaxation oscillations, and it was observed that stronger reabsorption leads to a lower relaxation oscillation frequency, while higher pump power results in a higher relaxation oscillation frequency. These results deepen the understanding of the physical mechanisms underlying self-pulsing in gain fibers.
Numerical and experimental study on forming characteristics of jet from nylon–water composite liner and its penetration performance on steel targets
Compared to traditional metal jets, shaped charge water jets offer the advantage of low-collateral-damage when destroying explosives. To investigate the forming characteristics and penetration performance of Nylon–Water Composite Jet (NWCJ), this study designed a 3D-printed Nylon–Water Composite Liner. Combining numerical simulation with experimental validation, the formation and penetration characteristics of polymer–liquid composite jets were studied. First, numerical simulations analyzed the forming characteristics and penetration performance of the nylon–water jet. Subsequently, the shaped charge was fabricated using selective laser sintering powder printing technology, overcoming the key technical challenge of solid–liquid coupling. Finally, static armor penetration tests validated the reliability of numerical simulations. Results indicate that compared to the Single Nylon Liner, the NWCJ exhibits significantly greater head expansion and higher velocity during the formation process. By regulating the water layer thickness, the NWCJ can effectively control penetration depth while maintaining hole-enlarging capability. The differing kinetic energy decay sequences of nylon and water reveal the penetration mechanism of polymer–liquid composites. This study provides guidance for designing polymer–liquid composite liner structures and enhances understanding of the formation and penetration of polymer–liquid composite jets under explosive loading.
Comment on “Determining angle of arrival of radio-frequency fields using subwavelength, amplitude-only measurements of standing waves in a Rydberg atom sensor” [J. Appl. Phys. 138, 114402 (2025)]
Impact of field stress pattern on the performance of HfO2-based ferroelectric tunnel junctions
In this study, we examine the performance of the Hf0.5Zr0.5O2/Y2O3 bilayer ferroelectric tunnel junction under both unipolar and bipolar stress conditions. The introduction of a delay time between consecutive pulses clarified the role of charge traps and defect formation in modulating the tunneling current of the device. In the context of unipolar stress pulses, the dynamics of electron trapping and detrapping are essential for the accumulation of charges at the ferroelectric/dielectric interfaces. In addition to the inherent polarity of these trapped charges, the duration between consecutive pulses plays a crucial role in determining the extent of trap filling at these interfaces. This, in turn, critically influences the On to Off ratio, either by diminishing or enhancing it. When the device was subjected to alternating positive and negative switching pulses, defect formation occurred within the device stack. This results in a significant enhancement of the On and Off currents, increasing by more than two orders of magnitude. By appropriately engineering the delay interval between the alternating pulses, we observed an On to Off ratio exceeding 100, indicating that the contribution of trapped charges is the primary cause of current modulation over field cycles.
Verification of the resonance properties of the electromagnetic dipole-hybrid mode and magnetic toroidal dipole mode of the metasurface and its clothing fabric sensing performance
Here, a metasurface design strategy with high-quality factors and figure of merit (FOM) value is proposed and verified in the 4.0–20.0 THz range. By introducing symmetry breaking, the disk array is transformed into a tetramer cluster structure. The electromagnetic dipole-hybrid (ED–MD) mode and the magnetic toroidal dipole (MTD) mode are excited by the proposed metasurface. The ED–MD mode and MTD mode show high quality factors and extremely narrow bandwidth, which are beneficial for clothing fabric sensing applications. The amplitude and resonance positions can be modulated by using asymmetric parameters. The ED–MD mode exhibits a measured refractive index sensitivity of 921.25 GHz/RIU, and the corresponding FOM value is 3.56 × 104 in the clothing fabric sensing. This proposed metasurface verifies the asymmetric resonance characteristics and the clothing fabric sensing applications.
Exchange bias effects in Co3C/CoFe2O4 FM/FiM nanocomposites
The exchange bias effects in hard/soft magnetic nanocomposites are of significant interest for spintronic and high-density data storage applications. However, to get stable exchange bias through interfacial coupling remains main challenge. Here, Co3C/CoFe2O4 FM/FiM nanocomposite is successfully synthesized via the polyol reduction method to investigate the role of interfacial exchange interactions between ferromagnetic Co3C and ferrimagnetic CoFe2O4 phases. The structural characterization confirmed the coexistence of both phases with nanoscale crystallinity, while magnetic measurements revealed strong temperature-dependent hysteresis behavior. A large coercivity of ∼7899 Oe at 50 K and ∼655 Oe at 300 K was observed, along with a clear exchange bias field of 6–169 Oe at 300–50 K, showing enhanced interfacial spin coupling. The zero-field-cooled and field-cooled magnetization curves showed a blocking temperature above 400 K, indicating strong magnetocrystalline anisotropy and significant interfacial exchange coupling in the nanocomposite. The observed exchange bias is attributed to exchange coupling between the hard CoFe2O4 phase and the ferromagnetic Co3C phase at their interfaces. The maximum energy density (BH)max of the nanocomposite ranges from 3 to 97 MGOe, and the magnetic anisotropy constant ranges from 0.1005 to 1.3879 × 105 Jm−3 at 300–50 K. This work is considered a first study of exchange coupling between a ferromagnetic metal carbide (Co3C) and a ferrimagnetic oxide (CoFe2O4), establishing how carbon at the magnetic interface modifies exchange anisotropy and reversal mechanisms in a rare-earth-free hard/hard bi-magnetic system. These findings open a route for a novel composite and its potential for spintronics and rare-earth-free magnets.
Quercetin modulates mast cell activation and the IL-33/ST2/NF-κB axis in allergic rhinitis
Abstract Allergic rhinitis (AR) is driven by immunoglobulin E (IgE)-mediated mast cell (MC) activation, leading to degranulation and type 2 cytokine release. Quercetin has shown anti-allergic effects, but its precise mechanism in AR remains incompletely understood. Quercetin’s impact on interleukin-33 (IL-33)-stimulated rat basophilic leukemia-2H3 (RBL-2H3) cells was assessed using both direct IL-33 exposure and IgE-mediated activation via anti-dinitrophenyl (DNP)-IgE sensitization and DNP- conjugated human serum albumin (HSA) challenge. Cytokine secretion, degranulation, apoptosis, and expression of IL-33 /suppression of tumorigenicity 2 (ST2)/nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathway components were assessed using enzyme-linked immunosorbent assay (ELISA), Western blotting, and reverse transcription quantitative polymerase chain reaction (RT-qPCR). A mouse model of AR induced by ovalbumin (OVA) was employed to assess in vivo efficacy. Symptom scores, inflammatory cytokine levels, nasal mucosal histology, and key signaling molecule expression were analyzed to confirm quercetin’s protection. Quercetin significantly suppressed IL-33-induced cytokine production, degranulation, and apoptosis in vitro; these effects were partially reversed by ST2 overexpression. In vivo, quercetin alleviated AR symptoms, reduced serum T helper 2 (Th2) cytokines, OVA-specific IgE (OVA-sIgE), and IL-33 levels, improved histopathology, and downregulated IL-33/ST2/NF-κB pathway proteins in nasal tissues. Our findings demonstrate quercetin’s anti-allergic effects against AR, which are likely mediated through suppression of mast cell activation and inhibition of the IL-33/ST2/NF-κB signaling cascade.
Energy-controlled supercapacitors based on polybenzidine-oxidant-GO hybrid electrodes with vanadate and dichromate redox chemistry
Physical therapy using digital therapeutics in infants with congenital muscular torticollis: a pilot study
Abstract Congenital muscular torticollis (CMT) is a common musculoskeletal problem associated with unilateral sternocleidomastoid muscle stiffness. We evaluated the feasibility of the newly developed digital therapeutics (DTx) ACESO-APP, a personalized exercise app with real-time feedback, using skeleton-based motion analysis and artificial intelligence-driven body reconstruction models. Fourteen participants were randomized to undergo either weekly PT with standard home program education (SE group) or weekly PT with digital therapeutics lead home program (DTx group). A 12-week home exercise program (HEP) comprising stretching exercises was encouraged in both groups with weekly in-hospital PT. Clinical changes were assessed using the torticollis overall assessment at 4, 8, and 12 weeks, and participants’ HEP adherence over 1 week was assessed using a questionnaire. Recruitment and completion rates, adherence rate, System Usability Scale scores, and adverse events were summarized using descriptive statistics. Eight participants (4 in each group) completed the study. The overall recruitment rate was approximately 5.2 participants per month, and the completion rate was 57.1% for both groups. The DTx group demonstrated higher adherence, with no reported adverse events. ACESO-APP demonstrated feasibility but achieved a suboptimal completion rate. These preliminary findings support large-scale trials and further optimization of HEP using the ACESO-APP in children with CMT.
Obesity, food habits and socio-demographic factors among university students in Germany: a cross-sectional study
Abstract Obesity represents a growing public health challenge globally, with rising prevalence among university students. Its causes extend beyond diet and exercise, encompassing socioeconomic background, and family education and migration history. This study examined obesity among German university students using data from the 2016 Studitemps survey, which included over 9,960 participants and mirrors key characteristics of national statistics and the largest social study of German students “Sozialerhebung 2016”. Logistic regression results indicate that with each additional year, the associated chance of obesity increases. Students whose parents hold university degrees had significantly lower associated chances of obesity—nearly half—compared to those whose parents had not attained any university entry-level qualification (OR = 0.536). Furthermore, living alone or with a partner, as opposed to in shared accommodation, was associated with higher odds of obesity (OR = 1.878), as was frequent use of food delivery services (OR = 1.498). Student income showed no association with obesity in either the regression or descriptive analyses; however, students with obesity appeared more reliant on student loans. Public and university initiatives should focus on at-risk groups by improving access to shared accommodations, promoting healthier food choices to reduce reliance on delivery services, and addressing cultural challenges faced by students from lower-education households. In conclusion, this study highlights the complex interplay of socio-demographic and lifestyle factors in obesity among university students.