Transition Rates Research Articles

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.

The evolution of accreting population III stars at 10−6–103 M⊙ yr−1

Context. The first stars formed over five orders of magnitude in mass by accretion in primordial dark matter halos. Aims. We study the evolution of massive, very massive and supermassive primordial (Pop III) stars over nine orders of magnitude in accretion rate. Methods. We use the stellar evolution code GENEC to evolve accreting Pop III stars from 10−6–103 M⊙ yr−1 and study how these rates determine final masses. The stars are evolved until either the end central Si burning or they encounter the general relativistic instability (GRI). We also examine how metallicity affects the evolution of the star at one accretion rate. Results. At rates below ∼2.5 × 10−5 M⊙ yr−1 the final mass of the star falls below that required for pair-instability supernovae. The minimum rate required to produce black holes with masses above 250 M⊙ is ∼5 × 10−5 M⊙ yr−1, well within the range of infall rates found in numerical simulations of halos that cool via H2, ≲10−3 M⊙ yr−1. At rates of 5 × 10−5 M⊙ yr−1 to 4 × 10−2 M⊙ yr−1, like those expected for halos cooling by both H2 and Lyα, the star collapses after Si burning. At higher accretion rates the GRI triggers the collapse of the star during central H burning. Stars that grow at above these rates are cool red hypergiants with effective temperatures log(Teff) = 3.8 and luminosities that can reach 1010.5 L⊙. At accretion rates of 100–1000 M⊙ yr−1 the gas encounters the general relativistic instability prior to the onset of central hydrogen burning and collapses to a black hole with a mass of ∼106 M⊙ without ever having become a star. Conclusions. Our models corroborate previous studies of Pop III stellar evolution with and without hydrodynamics over separate, smaller ranges in accretion rate. They also reveal for the first time the critical transition rate in accretion above which catastrophic baryon collapse, like that which can occur during galaxy collisions in the high-redshift Universe, produces supermassive black holes via dark collapse.

Wage employment, unemployment and self-employment across countries

Poor countries have low wage employment and high self-employment. This paper shows that they also have high unemployment relative to wage employment, and that self-employment increases with this ratio. To understand the sources of these patterns, I build a search and matching model with choice between job search and self-employment and with learning about matches, and calibrate it to match all transition rates between wage employment, unemployment and self-employment as well as separation hazards by job duration, separately for all 37 countries with available data. Quantitative analysis of the model shows that labor market frictions affect self-employment as much as unemployment. Labor market frictions also reduce aggregate output, not only by raising unemployment, but also by worsening the average quality of both wage employment matches and active self-employment projects.

Theoretical comparison of transition rate B(E2) and deformation parameter with experimental data for calcium (20Ca) isotopes using shell model theory

A theoretical comparison has been made for some calcium isotopes ([Formula: see text]Ca) which are even–even nuclei and have the atomic mass (Z = 20) with its previous experimental data. Theoretical calculations of some [Formula: see text]Ca isotopes (A = 42, 44, 46, 48, 50, 52) adopted by the shell model theory were performed to calculate the transition rate B(E2), theoretical intrinsic quadruple moments ([Formula: see text] and theoretical deformation parameters ([Formula: see text], [Formula: see text] were calculated by two methods by using different effective interactions for each isotope such as, su3fp, fpbm, fprkb, fpd6, kb3. Through code NuShellX@MSU, the single-body density matrix was calculated. The effects of the core polarization were neglected by adopting various effective charges that were employed, effective charges of conventional (Con-E), effective charges of standard (St-E) and effective charges of Bohr and Mottelson (B-M-E) which were calculated. The theoretical values of the B(E2)Th, the [Formula: see text] and the ([Formula: see text], [Formula: see text] were then compared with the previous experimental data where values of the transition rate B(E2)Th, theoretical intrinsic quadrupole moments [Formula: see text] and theoretical deformation parameter ([Formula: see text], [Formula: see text], using the fpbm, the fpd6 and the kb3 interactions were the best.

Topological equivalence and phase transition rate in holographic thermodynamics of regularized Maxwell theory

Utilizing the holographic dictionary from the proposal that treats Newton’s constant as a thermodynamic variable, we establish a thermodynamic topological equivalence between the AdS black holes in the bulk and the thermal states in the dual CFT. The findings further reveal that the thermodynamic topological characteristics of the RegMax AdS black holes are strongly influenced by the characteristic parameter of the regularized Maxwell theory. Additionally, we investigate the phase transition between low and high entropy thermal states within a canonical ensemble in the dual CFT. Our observations indicate that the phase transition behavior of the thermal states mirrors that of the black holes. By modeling the phase transition process as a stochastic process, we are able to calculate the rates of phase transition between the thermal states. This result enhances our understanding of the dominant processes involved in the phase transition of the thermal states in the dual CFT.

Changes in neighborhood disadvantage over the course of 22 years among community-living older persons.

Among older persons, neighborhood disadvantage is a granular and increasingly used social determinant of health and functional well-being. The frequency of transitions into or out of a disadvantaged neighborhood over time is not known. These transitions may occur when a person moves from one location to another or when the Neighborhood Atlas, the data source for the area deprivation index (ADI) that is used to identify disadvantaged neighborhoods at the census-block level, is updated. From a prospective longitudinal study of community-living persons, aged 70 years or older in South Central Connecticut, neighborhood disadvantage was ascertained every 18 months for 22 years (from March 1998 to March 2020). ADI scores higher than the 80th state percentile were used to distinguish neighborhoods that were disadvantaged (81-100) from those that were not (1-80). At baseline, 205 (29.3%) of the 699 participants were living in a disadvantaged neighborhood. Changes in neighborhood disadvantage during 14 consecutive 18-month intervals were relatively uncommon, ranging from 1.5% to 11.8%. Nearly 80% of participants had no change in neighborhood disadvantage and less than 4% had more than one change over a median follow-up of more than 9 years. Overall, the rate of transitions into or out of neighborhood disadvantage was only 2.7 per 100 person-years. These transitions were most common when the Neighborhood Atlas was updated (2013, 2015, 2018, and 2020). Comparable results were observed when decile changes in ADI scores during the 18-month intervals were evaluated. In longitudinal studies of older persons with extended follow-up, it may not be necessary to update information on disadvantaged neighborhoods in circumstances when it is possible, and the degree of misclassification of neighborhood disadvantage should be relatively low in circumstances when updated information cannot be obtained.

Golden Flower Tibetan Tea Polysaccharides Alleviate Constipation in Mice by Regulating Aquaporins-Mediated Water Transport System and Gut Microbiota.

Constipation, a widespread gastrointestinal disorder, often leads to the exploration of natural remedies. This study examines the efficacy of Golden Flower Tibetan Tea Polysaccharides (GFTTPs) in alleviating constipation in mice. Chemical analyses reveal that GFTTPs possess O-H, carboxyl, carboxylic acid (-COOH), and C-O-C groups, alongside a porous crystal structure with thermal stability. In animal experiments, GFTTPs significantly upregulated aquaporin 3 (AQP3) and aquaporin 8 (AQP8) expressions in the colon, enhancing water absorption and reducing fecal water content. At a 400 mg/kg dosage, GFTTPs notably improved colonic tissue alterations and serum levels of excitatory neurotransmitters caused by loperamide hydrochloride. They also beneficially altered gut microbiota, increasing Coprococcus, Lactobacillus, and Pediococcus populations. These changes correlated with improved stool frequency, consistency, and weight in constipated mice. Importantly, GFTTPs at 200 and 400 mg/kg doses exhibited comparable effects to the normal control group in key parameters, such as gastrointestinal transit rate and fecal moisture. These findings suggest that GFTTPs may serve as a potent natural remedy for constipation, offering significant therapeutic potential within the context of gut health and with promising implications for human applications.

Finite‐time H∞ filtering for Markov jump systems with partially unknown transition rates

SummaryThe thesis studies a stochastic finite‐time bounded (SFTB) filter design method for time‐varying delay Markov jump systems (MJSs) with partially unknown transition rates. First, a Lyapunov–Krasovskii functional with triple integral is built, the free weight matrix is added for lowering the conservatism. And the condition of SFTB of the error system is analyzed. Then, according to linear matrix inequalities (LMIs), a new filter design method is presented. Moreover, the dimension of the filter obtained is free, and the filter ensures that the error system is SFTB. Finally, the validity and effectiveness of the conclusion of this paper are demonstrated by simulation examples.

Diffusion barriers imposed by tissue topology shape Hedgehog morphogen gradients

Animals use a small number of morphogens to pattern tissues, but it is unclear how evolution modulates morphogen signaling range to match tissues of varying sizes. Here, we used single-molecule imaging in reconstituted morphogen gradients and in tissue explants to determine that Hedgehog diffused extracellularly as a monomer, and rapidly transitioned between membrane-confined and -unconfined states. Unexpectedly, the vertebrate-specific protein SCUBE1 expanded Hedgehog gradients by accelerating the transition rates between states without affecting the relative abundance of molecules in each state. This observation could not be explained under existing models of morphogen diffusion. Instead, we developed a topology-limited diffusion model in which cell-cell gaps create diffusion barriers, which morphogens can only overcome by passing through a membrane-unconfined state. Under this model, SCUBE1 promoted Hedgehog secretion and diffusion by allowing it to transiently overcome diffusion barriers. This multiscale understanding of morphogen gradient formation unified prior models and identified knobs that nature can use to tune morphogen gradient sizes across tissues and organisms.

Z boson emission by an electron and the decays of Z boson into fermions in a de Sitter universe

In this paper we develop a method to obtain the rates for the decay of a Z boson into fermions in de Sitter geometry. Our general results obtained in de Sitter space-time allow us to obtain the Minkowski limits for the transition rates when the expansion parameter vanishes. Another important result reported in the present study is related to the emission of Z bosons by electrons and positrons. All the processes were studied by implementing perturbative methods that allow us to define the transition amplitudes in the first order of perturbation theory. The variation of probabilities and rates in terms of expansion parameter and particles masses is also given, pointing out that the processes that generate particle production are possible only in the early universe. For computing the transition rates and probabilities we use the dimensional regularization method and the minimal substraction method.

Advantages of Ultrathin AlN/GaN/AlN Quantum Wells for Excitonic Population Distribution and Transition Features Studied by Phononic–Excitonic–Radiative Model

Excitons are expected to be a high‐efficiency emission source in UV light‐emitting devices. However, the damping of the excitonic laser oscillation has been reported under conditions where the excitonic states are expected to be populated in the conventional theory. In order to understand the exciton dynamics under the thermal nonequilibrium state, a theoretical model including various energy species in semiconductors such as electrons, phonons, and photons is required. Herein, a 2D phononic–excitonic–radiative model is constructed to analyze the exciton dynamics in a 2D system. 2D excitons with four principal quantum number states and the continuum in the lowest energy level of the AlN/GaN/AlN quantum wells are considered. It is found that the 2D phonon significantly augments the excitation transition rate. When the high recombination rate corresponding to stimulated emission is considered, the exciton binding energy of 108 meV is not enough to reduce the population in the high‐order discreet states and the continuum states, while the binding energy of 215 meV corresponding to the one monolayer GaN has an advantage of reducing these populations. The analysis of population flux has an advantage in discussing the increase in the kinetic energy transfer to the 1S exciton.

Relaxation dynamics in the self-propelled Voronoi model for epithelial monolayers

Cell monolayers and epithelial tissues display slow relaxation dynamics during the reversible transition between mesenchymal and epithelial cells, a phenomenon directly relevant to embryogenesis, tumor metastases, and wound healing. In active cells, persistent motion induces collective dynamics that significantly influence relaxation behavior. To better understand the role of persistence in cell relaxations, we perform extensive simulations and employ cage-relative measures to address the previously overlooked system size effects in model active cells. We identify the glass transition at various persistence values, demonstrating conventional near-equilibrium supercooled dynamics at low persistence. However, highly persistent cells exhibit distinctive intermittent dynamics associated with intermittent local T1 transitions, where cell velocity correlates over space with a characteristic length ξ. More significantly, we formulate a universal relationship predicting the global relaxation time based on the T1 transition and the spatial velocity correlation across a wide range of persistence values. Specifically, the relaxation time demonstrates a power-law dependence on the irreversible T1 transition rate, multiplied by exp(ξ). Here, ξ vanishes at small persistence in nearly equilibrated cells, and the irreversible T1 transition rate diminishes towards the mode-coupling glass transition point. Published by the American Physical Society 2024

Effect of present state bias on minimal important change estimates: a simulation study.

The minimal important change (MIC) in a patient-reported outcome measure is often estimated using patient-reported transition ratings as anchor. However, transition ratings are often more heavily weighted by the follow-up state than by the baseline state, a phenomenon known as "present state bias" (PSB). It is unknown if and how PSB affects the estimation of MICs using various methods. We simulated 3240 samples in which the true MIC was simulated as the mean of individual MICs, and PSB was created by basing transition ratings on a "weighted change", differentially weighting baseline and follow-up states. In each sample we estimated MICs based on the following methods: mean change (MC), receiver operating characteristic (ROC) analysis, predictive modeling (PM), adjusted predictive modeling (APM), longitudinal item response theory (LIRT), and longitudinal confirmatory factor analysis (LCFA). The latter two MICs were estimated with and without constraints on the transition item slope parameters (LIRT) or factor loadings (LCFA). PSB did not affect MIC estimates based on MC, ROC, and PM but these methods were biased by other factors. PSB caused imprecision in the MIC estimates based on APM, LIRT and LCFA with constraints, if the degree of PSB was substantial. However, the unconstrained LIRT- and LCFA-based MICs recovered the true MIC without bias and with high precision, independent of the degree of PSB. We recommend the unconstrained LIRT- and LCFA-based MIC methods to estimate anchor-based MICs, irrespective of the degree of PSB. The APM-method is a feasible alternative if PSB is limited.

Laboratory Transition-rate Measurement of the Coronal Intercombination Line of Ar xv by Time-resolved Laser Spectroscopy

The extreme-ultraviolet emission line (424 Å) of the intercombination 1s 22s 2 1 S 0–1s 22s2p 3 P 1 transition of Ar xv can potentially characterize the electron temperature of astrophysical plasma. Various theoretical studies have investigated the intercombination transition rate, which is essential for the plasma diagnostics; however, experimental difficulties have prevented its measurement. We present here measurement of the lifetime of the 3 P 1 excited state of Ar xv, providing the experimental value of the intercombination transition rate. Employing time-resolved plasma-assisted laser spectroscopy, a method we recently demonstrated, enables us to measure this submicrosecond lifetime. The experimental result exhibits a 25%–43% higher transition rate than theoretical predictions.

Concurrent Care and Use of Advanced Cardiac Therapies for Hospitalized Veterans With Heart Failure

ContextConcurrent care allows patients to receive hospice while continuing disease-directed therapies. This treatment model is available in the Veterans Administration (VA) medical system, but its use in Veterans with heart failure (HF) is unexplored. ObjectiveTo compare use of advanced HF therapies 30 days posthospitalization in Veterans on hospice versus not on hospice following admission for HF exacerbation. MethodsWe evaluated Veterans admitted for HF exacerbation to VA hospitals between Jan 2011 and June 2019 who received advanced HF therapies, hospice services, or both postdischarge. Concurrent care was defined as receiving both hospice services and advanced HF therapies. Demographics, comorbidities, and prior healthcare utilization were compared. Secondary outcomes included burdensome transitions and mortality. ResultsAmong 317,967 HF Veterans, 18,350 (5.8%) chose hospice posthospitalization. Only 58 hospice-enrolled Veterans (0.3%) received advanced HF therapies (i.e. concurrent care) within 30 days postdischarge. Of 299,617 Veterans not on hospice, 6,083 (2.0%) received advanced HF therapies (0.3% vs. 2.0%; P < 0.001). Veterans receiving concurrent care had higher six-month mortality than those receiving advanced HF therapies alone (77.6% vs. 14.9%, SMD 1.61). Hazard of burdensome transitions was similar (adjusted HR 1.44, 95% CI 0.95–2.17). ConclusionVeterans with HF receiving concurrent care were few and experienced higher mortality. Rate of burdensome transitions was similar between Veterans receiving concurrent care and those not on hospice. Further research may explore why Veterans infrequently utilize concurrent care at the end of life.

Changing patterns of cigarette and ENDS transitions in the USA: a multistate transition analysis of adults in the PATH Study in 2017–2019 vs 2019–2021

IntroductionThe use of cigarettes and electronic nicotine delivery system (ENDS) has likely changed since 2019 with the rise of pods and disposables, the lung injuries outbreak, flavour bans, Tobacco 21...

Mathematical modeling and quantitative analysis of phenotypic plasticity during tumor evolution based on single-cell data.

Tumor is a complex and aggressive type of disease that poses significant health challenges. Understanding the cellular mechanisms underlying its progression is crucial for developing effective treatments. In this study, we develop a novel mathematical framework to investigate the role of cellular plasticity and heterogeneity in tumor progression. By leveraging temporal single-cell data, we propose a reaction-convection-diffusion model that effectively captures the spatiotemporal dynamics of tumor cells and macrophages within the tumor microenvironment. Through theoretical analysis, we obtain the estimate of the pulse wave speed and analyze the stability of the homogeneous steady state solutions. Notably, we employe the AddModuleScore function to quantify cellular plasticity. One of the highlights of our approach is the introduction of pulse wave speed as a quantitative measure to precisely gauge the rate of cell phenotype transitions, as well as the novel implementation of the high-plasticity cell state/low-plasticity cell state ratio as an indicator of tumor malignancy. Furthermore, the bifurcation analysis reveals the complex dynamics of tumor cell populations. Our extensive analysis demonstrates that an increased rate of phenotype transition is associated with heightened malignancy, attributable to the tumor's ability to explore a wider phenotypic space. The study also investigates how the proliferation rate and the death rate of tumor cells, phenotypic convection velocity, and the midpoint of the phenotype transition stage affect the speed of tumor cell phenotype transitions and the progression to adenocarcinoma. These insights and quantitative measures can help guide the development of targeted therapeutic strategies to regulate cellular plasticity and control tumor progression effectively.

Transitions of care for adolescents with disorders of gut-brain interaction.

Little is known about the experience of adolescents and young adults (AYA) with disorders of gut-brain interaction (DGBI) who transition from pediatric to adult gastroenterology care. In this two-part study, we used quantitative and qualitative methods to: (1) assess incidence of optimal versus suboptimal transitions of care for AYA with DGBI, (2) characterize health and quality of life effects of the transition, and (3) identify barriers and facilitators for optimal transition of care. In Part 1, we conducted a retrospective review of AYA referrals to our adult neurogastroenterology clinic who had transitioned from pediatric gastroenterology care (N = 109, 17-23 years, 72% female). We collected demographic, psychosocial, and healthcare utilization data to determine rate and risk factors for suboptimal transitions. In Part 2, we recruited 24 AYA and parents (n = 19 AYA, n = 5 parents) for completion of a survey and semistructured interview, which was analyzed using validated rapid qualitative analysis method. In Part 1, 20% (22/109) of AYA met the criteria for suboptimal transition of care, which was associated with treatment adherence concern and functional impairment. In Part 2, we identified two principal themes: (1) AYA's health and quality of life are impacted during the transition, and (2) parental involvement and collaboration with pediatric gastrointestinal (GI) are facilitators to successful transitions, whereas access to care and practice style change are barriers. AYA with DGBI have high rates of suboptimal care transitions, affecting their health and quality of life. Our study highlights the need for a comprehensive approach that incorporates parents and pediatric providers.

Linearly Arranged Multi‐π‐Stacked Structure for Efficient Through‐Space Charge‐Transfer Emitters

AbstractNoncovalent spatial interaction has become an intriguing and important tool for constructing optoelectronic molecules. In this study, we linearly attached three conjugated units in a multi π‐stacked manner by using just one trident bridge based on indeno[2,1‐b]fluorene. To achieve this structure, we improved the synthetic approach through double C−H activation, significantly simplifying the preparation process. Due to the proximity of the C10, C11, and C12 sites in indeno[2,1‐b]fluorene, we derived two novel donor|acceptor|donor (D|A|D) type molecules, 2DMB and 2DMFB, which exhibited closely packed intramolecular stacking, enabling efficient through‐space charge transfer. This molecular construction is particularly suitable for developing high‐performance thermally activated delayed fluorescence materials. With donor(s) and acceptor(s) constrained and separated within this spatially rigid structure, elevated radiative transition rates, and high photoluminescence quantum yields were achieved. Organic light‐emitting diodes incorporating 2DMB and 2DMFB demonstrated superior efficiency, achieving maximum external quantum efficiencies of 28.6 % and 16.2 %, respectively.

Linearly Arranged Multi-π-Stacked Structure for Efficient Through-Space Charge-Transfer Emitters.

Noncovalent spatial interaction has become an intriguing and important tool for constructing optoelectronic molecules. In this study, we linearly attached three conjugated units in a multi π-stacked manner by using just one trident bridge based on indeno[2,1-b]fluorene. To achieve this structure, we improved the synthetic approach through double C-H activation, significantly simplifying the preparation process. Due to the proximity of the C10, C11, and C12 sites in indeno[2,1-b]fluorene, we derived two novel donor|acceptor|donor (D|A|D) type molecules, 2DMB and 2DMFB, which exhibited closely packed intramolecular stacking, enabling efficient through-space charge transfer. This molecular construction is particularly suitable for developing high-performance thermally activated delayed fluorescence materials. With donor(s) and acceptor(s) constrained and separated within this spatially rigid structure, elevated radiative transition rates, and high photoluminescence quantum yields were achieved. Organic light-emitting diodes incorporating 2DMB and 2DMFB demonstrated superior efficiency, achieving maximum external quantum efficiencies of 28.6 % and 16.2 %, respectively.