Transition Rates Research Articles

Non-equilibrium rate theory for polariton relaxation dynamics.

We derive an analytic expression of the non-equilibrium Fermi's golden rule (NE-FGR) expression for a Holstein-Tavis-Cumming Hamiltonian, a universal model for many molecules collectively coupled to the optical cavity. These NE-FGR expressions capture the full-time-dependent behavior of the rate constant for transitions from polariton states to dark states. The rate is shown to be reduced to the well-known frequency domain-based equilibrium Fermi's golden rule (E-FGR) expression in the equilibrium and collective limit and is shown to retain the same scaling with the number of sites in non-equilibrium and non-collective cases. We use these NE-FGR to perform population dynamics with a time-non-local and time-local quantum master equation and obtain accurate population dynamics from the initially occupied upper or lower polariton states. Furthermore, NE-FGR significantly improves the accuracy of the population dynamics when starting from the lower polariton compared to the E-FGR theory, highlighting the importance of the non-Markovian behavior and the short-time transient behavior in the transition rate constant.

Nocturnal Sleep Dynamics Alterations in the Early Stages of Behavioral Variant Frontotemporal Dementia.

Sleep disorders have been recognized as an integral component of the clinical syndrome in several neurodegenerative diseases, including Alzheimer's Disease (AD). However, limited data exists for rarer types of neurodegenerative diseases, such as behavioral variant Frontotemporal Dementia (bvFTD). This study aims to analyze EEG power spectra and sleep stage transitions in bvFTD patients, hypothesizing that bvFTD may show distinctive sleep stage transitions compared to patients with Alzheimer's Disease (AD). Eighteen probable bvFTD patients and eighteen age- and sex-matched probable AD patients underwent overnight polysomnography (PSG) and completed sleep disorders questionnaires. Sleep questionnaires, full-night EEG spectra, and sleep stage transitions indexes were compared between groups. bvFTD patients had higher Insomnia Severity Index (ISI) scores (95%CI: 0, 5) and reported poorer sleep quality than AD patients (p<0.01). Compared to AD, bvFTD patients showed higher N1 percentage (95%CI: 0.1, 6), lower N3 percentage (95%CI: -13.6, -0.6), higher sleep-wake transitions (95%CI: 1.49, 8.86) and N1 sleep-wake transitions (95%CI: 0.32, 6.1). EEG spectral analysis revealed higher spectral power in bvFTD compared to AD patients in faster rhythms, especially sigma rhythm, across all sleep stages. In bvFTD patients, sleep-wake transitions were positively associated with ISI. Patients with bvFTD present higher rates of transitions between wake and sleep than AD patients. The increased frequency of sleep transitions indicates a higher degree of sleep instability in bvFTD, which may reflect an imbalance in sleep-wake promoting systems. Sleep stage transitions analysis may provide novel insights into the sleep alterations of bvFTD patients.

Surface Iodide Defects Control the Kinetics of the CsPbI3 Perovskite Phase Transformation.

Halide perovskites are technologically interesting across a wide range of optoelectronic devices, especially photovoltaics, but material stability has proven to be challenging. One degradation mode of note is the meta stability of the perovskite phase of some material compositions. This was studied by tracking the change of CsPbI3 from its optoelectronically relevant perovskite phase to its thermodynamically stable nonperovskite phase, δ-CsPbI3. We explore kinetics as a function of surface chemistry and observe a quantitatively similar, ∼5-fold, reduction in the phase transition rate between neat films and those treated with CsI and CdI2. Using XPS to explore surface chemistry changes across samples, we link the reduction in the phase transition rate to the surface iodide concentration. When informed by previous theoretical studies, these experiments point to surface iodide vacancies as the nucleation sites for δ-CsPbI3 growth and show that phase nucleation is the rate limiting step in δ-CsPbI3 formation for CsPbI3 perovskite thin films.

Bifidobacterium longum subsp. infantis NKU FB3-14 attenuates loperamide-induced constipation through regulation of gut microbiota

Abstract Objectives Constipation is a prevalent gastrointestinal issue, and the efficacy of probiotics in alleviating constipation has been well proved. This study aimed to investigate the impact of Bifidobacterium longum subsp. infantis NKU FB3-14 on loperamide- induced constipation by focusing on improving intestinal barrier function and modulating gut microbiota composition Materials and Methods The constipated model mice induced by loperamide were treated with NKU FB3-14, and the laxative effect was assessed based on the fecal water content, first black stool time and gastrointestinal transit rate. Gastrointestinal regulatory peptides in serum, intestinal neurotransmitter and inflammatory cytokines in colon tissues were measured using ELISA kits. Changes of gut microbiota composition were analyzed through 16S ribosomal DNA sequencing identification. Additionally, HPLC detection was performed to quantify short chain fatty acids levels in feces Results Treatment with NKU FB3-14 led to increase the fecal water content, shorten the first black stool time and improve small intestine transit rate. Motilin and substance-P significantly decreased in the model group, and only motilin increased in FB3-14 group; somatostatin and vasoactive intestinal peptide were decreased in model mice and both increased in FB3-14 group; 5-HT levels in the colon tissue were upregulated following NKU FB3-14 treatment. Histological examination revealed thinner colonic mucosa in the model group along with significant in TNF-α, IL-1β and IL-17 levels form the colon tissues which were all relieved by NKU FB 3-14 treatment. Furthermore, NKU FB3-14 intervention resulted in reduced abundance of Desulfobacterota and Desulfovibrio while increasing the abundance of Ruminococcaceae and Eubacterium; higher level of butyric acid was observed in feces Conclusions In summary, our findings demonstrated that NKU FB3-14 treatment significantly enhanced the intestinal motility, regulated the expression levels of gastrointestinal regulatory peptides, prevented damage to colonic barriers as well as ameliorated gut microbiota imbalance associated with loperamide-induced constipation.

Prevalence and risk of subthreshold anxiety developing into threshold anxiety disorder in the general population

BackgroundSubthreshold anxiety may act as a critical precursor and risk factor for the onset of threshold anxiety. However, accurate prevalence rates of subthreshold anxiety and its role in leading to threshold anxiety require further elucidation. MethodsWe conducted a search on PubMed and Web of Science using predefined criteria and identified 45 articles with a total of 278,971 individuals to estimate the prevalence rates using a random effects model. The incidence risk ratio (IRR) was estimated by comparing the proportion of individuals with subthreshold anxiety who developed threshold anxiety to those without subthreshold anxiety in seven articles involving 18,693 individuals. ResultsOur analysis revealed an overall prevalence of subthreshold anxiety of 6.19%. Specifically, among individuals with subthreshold generalized anxiety disorders, adolescents show the highest prevalence (9.47%), outpacing adults (4.69%) and the elderly (3.49%). Further analysis of seven studies showed an increased risk of developing threshold anxiety in individuals with subthreshold anxiety (IRR = 2.63), with a higher transition rate (9.59%) compared to those without subthreshold anxiety (3.65%). ConclusionsAnxiety disorders may be conceptualized as a spectrum, with subthreshold anxiety serving as a significant prodromal state and risk factor for the development of threshold anxiety. Proactive management of subthreshold anxiety represents an effective approach for the prevention of its progression to threshold anxiety. Future research should investigate the risk of progression from subthreshold to threshold anxiety across various types, and explore how factors, such as social support and personality traits facilitate this progression.

First Achievement of Yellow Laser Operation in Dy3+-Doped Borate Crystals.

Continuous-wave (CW) yellow lasers have been demonstrated successfully by using a GaN laser-diode (LD) pumping in borate crystals for the first time. The Dy3+:GdMgB5O10 (Dy:GMB) crystal with dimensions up to 33 × 19 × 15 mm3 is grown by the top-seeded solution growth method, and the polarized spectroscopic properties are investigated systematically at room temperature. The line strengths, Judd-Ofelt (J-O) intensity, spontaneous transition rates, fluorescence branching ratios, and radiative lifetimes are calculated in detail by the Judd-Ofelt theory. Under direct pumping of 452 nm LD, a compact continuous-wave yellow laser with a maximum output power of 628 mW and laser wavelength of 581 nm is generated based on a Y-cut Dy:GMB crystal. To our knowledge, it is not only the highest output power for yellow laser obtained in Dy3+-doped crystals but also the first yellow laser operation achieved by borate crystals under direct LD pumping. The results reveal that the Dy:GMB crystal is an optical material with important application prospects in yellow laser.

Entropy production of the contact model

Abstract We propose an expression for the production of entropy for a system described by a stochastic dynamics which is appropriate for the case where the reverse transition rate vanishes but the forward transition is nonzero. The expression is positive definite and based on the inequality x ln ⁡ x − ( x − 1 ) ⩾ 0 . The corresponding entropy flux is linear in the probability distribution allowing its calculation as an average. The expression is applied to the one-dimensional contact process at the stationary state. We found that the rate of entropy production per site is finite with a singularity at the critical point with diverging slope.

Random Telegraphic Signals with Fractal-like Probability Transition Rates

Many physical processes feature random telegraph signals, e.g., a time signal c(t) that randomly switches between two values over time. The present study focuses on the class of telegraphic processes for which the transition rates are formulated by using fractal-like expressions. By considering various restrictive hypotheses regarding the statistics of the waiting times, the present analysis provides the corresponding expressions of the unconditional and conditional probabilities, the mean waiting times, the mean phase duration, the autocorrelation function and the associated integral time scale, the spectral density, and the mean switching frequency. To assess the relevance of the various hypotheses, synthetically generated signals were constructed and used as references to evaluate the predictive quality of the theoretically derived expressions. The best predictions were obtained by considering that the waiting times probability density functions were Dirac peaks centered on the corresponding mean values.

Ab Initio Manganese Kα and Kβ Energy Eigenvalues, Shake-Off Probabilities, Auger Rates, with Convergence Tests.

This work presents ab initio calculations for the Kα spectrum of manganese (Z = 25, [Ar]3d54s2), a highly complex system due to the five open orbitals in the 3d shell. The spectrum is composed of the canonical diagram line [1s]→[2p] and shake-off satellite lines [1snl]→[2pnl] (nl∈{2s,2p,3s,3p,3d,4s}), where square brackets denote a hole state. The multiconfiguration Dirac-Hartree-Fock method with the active set approach provides the initial and final atomic wavefunctions. Results are presented as energy eigenvalue spectra for the diagram and satellite transitions. The calculated wavefunctions include over one hundred million configuration state functions and over 280,000 independent transition energies for the seven sets of spectra considered. Shake-off probabilities and Auger transition rates determine satellite intensities. The number of configuration state functions ensures highly-converged wavefunctions. Several measures of convergence demonstrate convergence in the calculated parameters. We obtain convergence of the transition energies in all eight transitions to within 0.06 eV and shake-off probabilities to within 4.5%.

Linear response theory for light dark matter-electron scattering in materials

We combine the nonrelativistic effective theory of dark matter (DM)-electron interactions with linear response theory to obtain a formalism that fully accounts for screening and collective excitations in DM-induced electronic transition rate calculations for general DM-electron interactions. In the same way that the response of a dielectric material to an external electric field in electrodynamics is described by the dielectric function, so in our formalism the response of a detector material to a DM perturbation is described by a set of which can be directly related to densities and currents arising from the nonrelativistic expansion of the Dirac Hamiltonian. We apply our formalism to assess the sensitivity of non-spin-polarized detectors, and find that in-medium effects significantly affect the experimental sensitivity if DM couples to the detector's electron density, while being decoupled from other densities and currents. Our formalism can be straightforwardly extended to the case of spin-polarized materials. Published by the American Physical Society 2024

Thermally Activated Delayed Fluorescence and Beyond. Photophysics and Material Design Strategies.

This review focuses on thermally activated delayed fluorescence (TADF). Photophysical properties of Cu(I) complexes and unique organic molecules are addressed. Investigations, based on temperature‐dependent emission studies, micro‐ to femto‐second time‐resolved spectroscopy investigations, quantum mechanical considerations, state‐of‐art calculations, and organic light‐emitting diodes (OLED) device studies, address exciton harvesting mechanisms and photophysical impact of the energy gap ΔE(S1–T1) and spin‐orbit coupling (SOC). We disclose relationship between (i) ΔE(S1–T1) and transition rate k(S1–S0); (ii) SOC, phosphorescence, and intersystem crossing (ISC); (iii) internal/external rigidity, luminescence quantum yield, excitation self‐trapping, and concentration quenching; (iv) environment polarity and state energy tuning, as well as (v) SOC and combined ambient‐temperature TADF/phosphorescence, zero‐field splitting, and spin‐lattice relaxation (at T = 1.2 K). These studies guide us to milestone Cu(I) complexes. Moreover, we demonstrate that fast ISC in organic molecules requires state mixing with an additional, energetically close triplet state. Thus, a guide structure for unique organic TADF molecules with ultra‐fast ISC and reverse‐ISC rates (&gt;109 s−1) combined with ΔE(S1–T1)&lt;10 cm−1 (&lt;1 meV) is presented allowing for ultra‐fast singlet‐triplet equilibrated fluorescence with sub‐microsecond decay. First OLEDs fabricated show high external quantum efficiency of ≈19%. Based on this breakthrough material class, a new exciton harvesting mechanism, the direct singlet harvesting (DSH), is presented.

Toward the design of highly waterproof‐breathable electrospun nanofiber membrane based on π–π interactions

AbstractWaterproof and breathable nanofiber membranes are highly desirable for protective textiles; however, the practical application of nanofiber membranes is limited by fluorine‐containing material addition or complicated post‐treatment. Herein, we reported unique fluorine‐free polyurethane (PU)/poly(styrene‐b‐s‐b‐styrene) (SBS) nanofiber membranes by a facile direct electrospinning. Owing to the addition of SBS, the hydrophobicity, waterproofness, and mechanical properties of PU nanofiber membranes were dramatically enhanced. Furthermore, the highly interconnective channels were constructed after the introduction of SBS into the PU nanofiber membrane, which resulted in enhanced breathability. The enhancement in the comprehensive performance of the PU/SBS composite nanofiber membrane might be attributed to the π–π interactions between SBS and PU. By adjusting the concentration of the PU/SBS, fluorine‐free PU/SBS nanofiber membranes were optimized systematically, exhibiting satisfactory waterproofness (hydrostatic pressure, 47.4 kPa), acceptable breathability (water vapor transition rate, 5.6 kg m−2 d−1), and outstanding mechanical properties (breaking strength, 5.7 MPa; breaking elongation, 387.9%). The PU/SBS‐14 nanofiber membrane is ideal for wearable textiles, especially for outdoor protective clothing, wound dressings, and medical gowns.

Pricing a Defaultable Zero-Coupon Bond under Imperfect Information and Regime Switching

We propose a pricing formula for a defaultable zero-coupon bond with imperfect information under a regime switching model using a structural form of credit risk modelling. This paper provides explicit representations of risky debt under regime switching with a constant interest rate and risky debt under regime switching with a regime switching interest rate. While the value of the firm’s equity is observed continuously, we assume that the total value of the firm is only observed at discrete times, such as the dates of the release of the firm’s annual reports, or quarterly reports. This uncertainty about the true value of the firm results in credit spreads that do not approach zero as the debt approaches maturity, which is a problem with many structural models. The firm’s value is typically decomposed into its equity and debt; however, we consider the asset–to–equity ratio, an accounting ratio used to examine a firm’s financial well-being. The parameters in our model are regime switching, where the regime can be thought of as the state of the economy. A Markov chain with a constant transition rate matrix produces the regime switching.

The Resurgence of Exogenous Psychosis: A Phenomenological Examination of Substance-Induced Psychopathology.

The psychopathological manifestations associated with substance use, including induced psychotic experiences, are increasingly relevant but not well-understood within the medical community. Novel psychoactive substances and potentiated old compounds like cannabis and cocaine have emerged as a global concern, especially among adolescents and young adults. Transition rates from substance-induced psychosis (SIP) to persistent psychosis are significant, particularly in cases of cannabis-induced psychosis. Scientific inquiry into induced psychotic phenomena has revealed differences between SIP and primary psychotic disorders, highlighting the risk factors associated with each. The concept of exogenous psychosis, including its toxic variant known as lysergic psychoma, provides valuable insights into the role of external factors in psychosis development. A phenomenological approach characterizes this disruption in perception as a shift in temporal and spatial dimensions, leading to auditory and visual hallucinations. The "twilight state" of consciousness plays a crucial role in the transition from substance use to psychosis, with implications for spatiality, intersubjectivity, and temporality. This complex path to psychosis challenges traditional diagnostic models and underscores the need for a more nuanced understanding of substance-induced psychopathological experiences.

A Markovian description of the multi-level source function and its application to the Lyman series in the Sun

Aims. We introduce a new method to calculate and interpret indirect transition rates populating atomic levels using Markov chain theory. Indirect transition rates are essential to evaluate interlocking in a multi-level source function, which quantifies all the processes that add and remove photons from a spectral line. A better understanding of the multi-level source function is central to interpret optically thick spectral line formation in stellar atmospheres, especially outside local thermodynamical equilibrium (LTE). Methods. We compute the level populations from a hydrogen model atom in statistical equilibrium, using the solar FALC model, a 1D static atmosphere. From the transition rates, we reconstruct the multi-level source function using our new method and compare it with existing methods to build the source function. We focus on the Lyman series lines and analyze the different contributions to the source functions and synthetic spectra. Results. Absorbing Markov chains can represent the level-ratio solution of the statistical equilibrium equation and can therefore be used to calculate the indirect transition rates between the upper and lower levels of an atomic transition. Our description of the multi-level source function allows a more physical interpretation of its individual terms, particularly a quantitative view of interlocking. For the Lyman lines in the FALC atmosphere, we find that interlocking becomes increasingly important with order in the series, with Ly-α showing very little, but Ly-β nearly 50% and Ly-γ about 60% contribution coming from interlocking. In some cases, this view seems opposed to the conventional wisdom that these lines are mostly scattering, and we discuss the reasons why. Conclusions. Our formalism to describe the multi-level source function is general and can provide more physical insight into the processes that set the line source function in a multi-level atom. The effects of interlocking for lines formed in the solar chromosphere can be more important than previously thought, and our method provides the basis for further exploration.

383. LOSS OF PERISTALTIC RESERVE DETERMINED BY MULTIPLE RAPID SWALLOWS CORRELATES WITH DYSPHAGIA AND POOR BOLUS TRANSIT IN INEFFECTIVE ESOPHAGEAL MOTILITY

Abstract Introduction Ineffective esophageal motility (IEM) is a common finding on high resolution esophageal manometry (HRM) and is often of unclear clinical significance as its impact on dysphagia and bolus transit is variable. Multiple rapid swallow (MRS) testing is a provocative maneuver performed during HRM that assesses peristaltic reserve, documented by the presence of contractile augmentation (defined by contractile vigor after MRS greater than that seen with single swallows). Lack of augmentation after MRS is associated with dysphagia after anti-reflux surgery. To date, no studies have evaluated the impact of peristaltic reserve on dysphagia and bolus transit in IEM patients. Methods Retrospective review of 159 patients with Chicago classification 4.0 IEM. 52 patients were excluded due to prior esophageal surgery, technically inadequate MRS, or concomitant esophagogastric junction outflow obstruction. Demographics and brief esophageal dysphagia questionnaire (BEDQ) results were obtained from a prospectively maintained database. MRS and bolus transit data were analyzed using a commercially available software. Impedance analysis documented complete versus incomplete bolus transit. Augmentation was defined as the ratio of post-MRS DCI to mean single swallow DCI &amp;gt; 1. Fisher's exact test for continuous data and linear model ANOVA were used to assess for statistical significance. Results 107 IEM patients were included, 46 of them had loss of peristaltic reserve (no augmentation on MRS). Compared to IEM patients with augmentation, those without augmentation had more severe dysphagia documented by higher mean BEDQ score (6.8 versus 4.8, p= 0.045), and increased rates of impaired bolus transit (73% versus 55%, p-= 0.013). Discussion IEM patients without augmentation on MRS have more severe dysphagia and more frequent incomplete bolus clearance. These findings support adding MRS response to the diagnosis of IEM or using it to describe a subset of patients with more severe disease.

Changing patterns of cigarette and ENDS transitions in the USA: a multistate transition analysis of youth and adults in the PATH Study in 2015–2017 vs 2017–2019

IntroductionIt is unknown how recent changes in the tobacco product marketplace have impacted transitions in cigarette and electronic nicotine delivery system (ENDS) use.MethodsA multistate transition model was applied to 24...

Refractive power profiles of commercially available soft multifocal contact lenses for myopia control.

Lens power profiles can provide valuable insights on the imposed optical defocus and visual experience of contact lens wearers, especially in the context of myopia control. This study measured the refractive power profiles of multifocal soft contact lenses (MFCLs) currently used or that have the potential for use in myopia control using high spatial resolution aberrometry. The instrument's repeatability for determining MFCLs power profiles was also assessed. The power profiles of 10 MFCLs of various designs (centre-distance, centre-near and extended depth of focus) were measured using the Lambda-X NIMOEVO, a phase shifting Schlieren-based device. Power profiles were graphically expressed as measured power at each chord position and the maximum add power was calculated. The repeatability of the NIMOEVO was expressed as the within-subject standard deviation at each chord position for a subset of five MFCLs. The measured distance powers differed from nominal powers for more than half of the MFCLs with a definable distance zone. There were variations in the chord position of the distance and near correction zones, rate of power transitions and calculated maximum add between the MFCLs which did not depend on lens design. For half of the MFCLs, the power profile shape was inconsistent between different nominal back vertex powers of the same design. The repeatability of the NIMOEVO was dependent on the lens design, with designs featuring faster rates of power change exhibiting worse repeatability. Significant differences in MFCL power profiles were found which were not adequately represented in labelling. This is likely due to the small number of parameters used to define lens power characteristics. Eye health care practitioners should be aware of potential differences in power profiles between different MFCLs, which will impact the retinal defocus introduced during lens wear and the wearer's visual experience.

Patterns of poly tobacco use among adults in the Population Assessment of Tobacco and Health (PATH) study, 2013–2017: a multistate Markov transition analysis

BackgroundA better understanding of sociodemographic transition patterns between single, dual and poly tobacco product use may help improve tobacco control policy interventions.MethodsHRs of transition between never, non-current (no past 30-day...

Antibacterial nanofibrous wound dressing mats made from blended chitosan-copper complexes and polyvinyl alcohol (PVA) using electrospinning

Chitosan is promising for wound care solutions owing to its high biocompatibility, biodegradability, hemostasis, antimicrobial activity, and promotion of tissue regeneration. However, its antibacterial property is insufficient for some infected wounds and local conditions. Given the high antibacterial activity of copper, this work focused on synthesizing chitosan-copper complexes with 1, 3, 6, 12, 24, and 48 % copper to chitosan's amine groups, followed by electrospinning them with polyvinyl alcohol. The mats exhibited promising vapor transition rates ranging from 2800 ± 33 to 3201 ± 48 g/m2.day and a dual-phase release of copper, with an initial burst followed by a sustained release over 7 days. Superior fibroblast cell cytocompatibility was observed up to 12 % copper, with accelerated re-epithelialization and cell migration to 6 % copper. Antibacterial efficacy against both gram-positive Staphylococcus aureus)S. aureus(and gram-negative Escherichia coli (E. coli) bacteria was effective beyond 3 % copper. Typically, the optimal concentration of copper was identified at 6 %, exhibiting a balance of antibacterial activity and biocompatibility, with the ability to cover 98.0 ± 0.8 % of the wound area in only 24 h and increase cell proliferation by 189 ± 11 % within 5 days.