Time-dependent Method Research Articles

Estimating real-time reproduction number for HPV infection in Xinjiang, China

Objective: This study aimed to investigate the prevalence of human papillomavirus (HPV) infection in Xinjiang, estimate the real-time reproduction number (Rt) of HPV infection, evaluate the effectiveness of local prevention and control policies, and provide a theoretical basis for cervical cancer (CC) control strategies in the region. Methods: Using the R0 package, the R software was employed to estimate the dynamic changes in the real-time reproduction number (Rt) of HPV infection in Xinjiang from January 2015 to December 2019. Four methods—Maximum Likelihood Estimation (ML), Exponential Growth (EG), Sequential Bayesian (SB), and Time-Dependent (TD)—were used to calculate the Rt values. The study compared the results from these methods to determine the most reliable approach for estimating HPV transmission. Results: Among the four methods, the TD method provided the best fit for observed and predicted cases. The estimated overall Rt was 1.1381 (95% CI: 1.0762–1.1972). For the periods 2015–2017 and 2017–2019, the Rt values were 1.2827 and 1.0544, respectively. Notably, the Rt value showed a downward trend after 2017 but remained above 1, indicating continued transmission of HPV. Conclusion: Although HPV infection rates in Xinjiang appear to be decreasing, the persistent Rt values suggest that HPV transmission has not been fully controlled. This highlights the urgent need for strengthened prevention and control measures to reduce HPV-related cervical cancer risk in the region.

Theoretical study by DFT and TD-DFT of NLO-active push-pull molecules composed of conjugated bridges based on cyclic rings: Titanol, Ferrol, Nickelol and Zinkol.

This research is based on the theoretical study of seven push-pull molecules composed of conjugated bridges based on two different organometallic rings, these bridges are linked at their ends by acceptor groups (-NO2) and donor groups (-N(CH3)2) on the α position of the rings mentioned above. The location of the donor and acceptor groups revealed that the addition of the acceptor groups near the rings (Titanol, Ferrol and Nickelol) improves the NLO response in comparison with the grafting of these groups on the Zinkol ring and also influences the positioning of the π electrons at the level of the chromophores studied. The molecule 2B gave the highest values ​​of static first hyperpolarisabilitiy (βtot) and static second hyperpolarisabilitiy (γav), knowing that: βtot (2B) = 135.79 * 10-30 esu and γav (2B) = 135.79 * 10-35 esu. The highest values ​​of dynamic first and second hyperpolarisabilities are assigned to the molecule 1C with the following values: =1,218,310.00 * 10-30 esu and =1,324,520,000 * 10-35 esu. The metal Zn is considered as an acceptor group and the remaining metals (Ti, Fe and Ni) are considered as donor groups. The specific solvents for the seven molecules are water, ethanol and acetonitrile. The maximum wavelengths recorded for all molecules in combination with all solvents are in the range of 421.39 to 765.28nm. λ METHOD: The calculations were performed using Gaussian 16 software to perform DFT calculations with B3LYP functional. The LanL2DZ basis-set was used for transition metals, while the 6-31 + + G(d,p) basis-set was used for nonmetal atoms. The functionals used are: CAM-B3LYP, LC-wPBE, LC-BLYP, M11, wB97X, M08-HX, M06-2X, MN12SX, MN15, and M06HF. The basis-sets used are: 6-31G(d,p), 6-31 + + G(d,p), cc-pVDZ, aug-cc-pVDZ, 6-311G(d,p), 6-311 + + G(d,p), cc-pVTZ, and aug-cc-pVTZ. The Natural Bond Orbital (NBO) calculations are performed by the NBO program incorporated by default in the Gaussian 16 program. The solvation models studied are the CPCM model (conductor polarizable continuum model) and the SMD model (Solvation Model Density). Excited states calculations are calculated by the time-dependent DFT method (TD-DFT).

Bay-Aminated Octaazaperopyrenedioxides (OAPPDOs) as Precursors for Diazepine and Diazepinone Derivatives.

Fully bay-aminated octaazaperopyrenedioxide (OAPPDO) derivatives have been accessible via Buchwald-Hartwig amination of the bay-chlorinated starting material. They were isolated as semiquinoidal species with a bent polycyclic core and characterized as nonfluorescent charge-transfer dyes. The corresponding secondary amines were synthesized by reduction and displayed typical absorption and emission behavior for perylene derivatives. One of the reduced amines served as a precursor for conversion of the secondary amino groups to 1,3-diazepine and -diazepinone units spanning the bay-area - seven-membered ring motifs hitherto unknown in perylene chemistry. The photophysical and electrochemical properties of the azaperylene dyes were investigated by absorption and emission spectroscopy supported by time-dependent density functional theory methods and cyclic voltammetry as well as differential pulse voltammetry.

Dynamics studies of H atom collision with KH molecule

Using the non-adiabatic potential energy surfaces (PESs) reported by Li et al. (Phys. Chem. Chem. Phys. 22 (2020) 16203), an in-depth examination of the abstraction and exchange reaction processes involving H colliding with KH was performed via the time-dependent wave packet method. The dynamics information is reported at state-to-state level of theory. Our findings suggest that the K(4p2P) + H2 product channel emerges through a non-adiabatic transition process. Given its similarity to the K(4s2S) + H2 product channel, this channel cannot be disregarded, particularly when J values are minimal. Additionally, our analysis revealed that among the three product channels of the H + KH reaction, the K(4s2S) + H2 channel consistently holds a dominant position. Scattering information from differential cross sections indicate that the forward abstraction reaction mechanism is predominant for the abstraction reaction, while the insertion reaction mechanism prevails for the exchange reaction.

An update on active and passive surveillance for African swine fever in the Dominican Republic

African swine fever (ASF) is a viral, hemorrhagic disease of swine that is reportable to the World Organisation for Animal Health. Since 2007, ASF has been expanding globally and causing severe disruption to the global swine industry. In 2021, ASF was detected in the Dominican Republic, prompting an emergency response from local and international officials. Three years later, ASF is still present in the country despite control efforts. This study used data from January 2023 to March 2024 from government-mandated sampling of commercial farms, a newly initiated active surveillance program of backyard farms, and passive reports to provide a comprehensive descriptive assessment of ASF in the Dominican Republic. The cumulative incidence for each region was calculated, and the reproductive ratio (R0) was estimated using doubling time and time-dependent methods. ASF continues to be distributed throughout the Dominican Republic with lower cumulative incidence in central regions and R0 around 1. These results suggest that ASF in the country is reaching a stable state that does not resemble an epidemic situation. This may suggest the need to change from an approach of emergency response to one of sustained and progressive control, ultimately for the long-term goal of ASF eradication in the Dominican Republic.

A computational study on the effect of structural isomerism on the excited state lifetime and redox energetics of archetype iridium photoredox catalyst platforms [Ir(ppy)2(bpy)]+ and Ir(ppy)3.

This study investigates the impact of structural isomerism on the excited state lifetime and redox energetics of heteroleptic [Ir(ppy)2(bpy)]+ and homoleptic Ir(ppy)3 photoredox catalysts using ground-state and time-dependent density functional theory methods. While the ground- and excited-state reduction potentials differ only slightly among the isomers of these complexes, our findings reveal significant variations in the radiative and non-radiative decay rates of the reactivity-controlling triplet 3MLCT states of these closely related species. The observed differences in radiative decay rates could be traced back to variations in the transition dipole moment, vertical energy gaps, and spin-orbit coupling of the isomers. In [Ir(ppy)2(bpy)]+, transition dipole moment differences play a significant role in controlling the relative lifetime of the triplet states, which we rationalized by a vectorial analysis of permanent dipole moments of the ground and excited states. Regarding the two isomers of Ir(ppy)3, changes in radiative decay rates were primarily attributed to variations in vertical energy gaps and intensity borrowing from other singlet-singlet transitions driven by spin-orbit coupling. Non-radiative decay variations were assessed in terms of differences in reorganization energies, adiabatic energy gap, and spin-orbit coupling. For both complexes, reorganization energies associated with low-energy molecular vibrations and metal-ligand bond length changes following the de-excitation process were major contributors. These insights provide a deeper understanding of how molecular design can be leveraged to optimize the performance of iridium-based photoredox catalysts, potentially guiding the development of more efficient catalytic systems for future applications.

Time-dependent nonlinear gravity–capillary surface waves with viscous dissipation and wind forcing

We develop a time-dependent conformal method to study the effect of viscosity on steep surface waves. When the effect of surface tension is included, numerical solutions are found that contain highly oscillatory parasitic capillary ripples. These small-amplitude ripples are associated with the high curvature at the crest of the underlying viscous-gravity wave, and display asymmetry about the wave crest. Previous inviscid studies of steep surface waves have calculated intricate bifurcation structures that appear for small surface tension. We show numerically that viscosity suppresses these. While the discrete solution branches still appear, they collapse to form a single smooth branch in the limit of small surface tension. These solutions are shown to be temporally stable, both to small superharmonic perturbations in a linear stability analysis, and to some larger amplitude perturbations in different initial-value problems. Our work provides a convenient method for the numerical computation and analysis of water waves with viscosity, without evaluating the free-boundary problem for the full Navier–Stokes equations, which becomes increasingly challenging at larger Reynolds numbers.

Finite-Element-Based Time-Dependent Service Life Prediction for Carbonated Reinforced Concrete Aqueducts

This study proposes a time-dependent reliability analysis method for aqueduct structures based on concrete carbonation and finite element analysis. The primary goal of this study is to improve the reliability assessment of reinforced concrete aqueducts by incorporating environmental factors such as carbonation over time. First, a three-dimensional finite element model of a reinforced concrete aqueduct is established using the Midas 2022 Civil software, incorporating a time-varying function derived from a predictive model of concrete carbonation depth. Point estimation is then integrated with structural finite element analysis to calculate the first four moments of random variables as functions of concrete carbonation. Additionally, the original performance function is transformed into a normal distribution using dual power transformation and the Jarque–Bera test. The high-order unscented transformation (HUT) is subsequently employed to estimate the first four moments of the transformed performance function, facilitating the calculation of time-varying reliability indices for the carbonated concrete aqueduct. Based on the time-varying reliability index data, a reliability function corresponding to different time points is fitted and applied to service life prediction. The results demonstrate that the proposed method effectively reduces large errors associated with the fourth-moment method in calculating large reliability indices. Furthermore, the comparison with Monte Carlo simulation (MCS) results validates the high efficiency and accuracy of the proposed method, offering a valuable tool for addressing the reliability challenges of aqueducts exposed to carbonation and other environmental factors over time.

Unraveling the effect of reagent vibrational excitation on the scattering mechanism of the benchmark H + H2 → H2 + H hydrogen exchange reaction in the coupled 12E' ground electronic manifold.

The hydrogen exchange reaction, H + H2 → H2 + H, along with its isotopic variants, has been the cornerstone for the development of new and novel dynamical mechanisms of gas-phase bimolecular reactions since the 1930s. The dynamics of this reaction are theoretically investigated in this work to elucidate the effect of reagent vibrational excitation on differential cross sections (DCSs) in a nonadiabatic situation. The dynamical calculations are carried out using a time-dependent quantum mechanical method, both on the lower adiabatic potential energy surface and employing a two-state coupled diabatic theoretical model to explicitly include all the nonadiabatic couplings present in the 12E' ground electronic manifold of the H3 system. Towards this effort, the Boothroyd-Keogh-Martin-Peterson (BKMP2) surface of the lower adiabatic component is coupled with the double many-body expansion (DMBE) surface of the upper one. The smooth variation of energy along the D3h seam of the conical intersections is explicitly confirmed. The coupled two-state calculations are performed only for H2 (v = 3-4, j = 0), as the minimum of the conical intersections becomes energetically accessible for these vibrational levels in the considered energy range. Initial state-selected total and state-to-state DCSs are calculated to elucidate various mechanistic aspects of reagent vibrational excitation. The latter enhances the forward scattering and makes the backward scattering less prominent. Important roles of collision energy in the vibrational energy disposal of both forward- and backward-scattered products are examined. Analysis of the state-to-state DCSs of the vibrationally excited reagents reveals an important correlation among scattering angle, and the product rotational angular momentum and its helicity state. Such an analysis establishes a novel mechanism for the forward scattering of the reaction.

Vibronic Interactions in the Photoelectron Spectra of CAl3Ge-: A Theoretical Study.

This study probes the vibronic interactions in the photoelectron spectra of CAl3Ge-, exploring its six excited electronic states through an approach that combines the ab initio electronic structure calculations and the quantum nuclear dynamics. Central to this investigation is utilizing a model diabatic Hamiltonian, which allows for the exact evaluation of Hamiltonian parameters and fitting potential energy cuts (PECs). Notably, the analysis of these PECs uncovers pronounced nonadiabatic effects within the photoelectron spectra, emphasized by the presence of multiple conical intersections. The investigation of nuclear dynamics, with and without the same spatial symmetry coupling, is achieved by employing time-dependent (TD) and time-independent (TI) quantum mechanical methods. These nuclear dynamical studies effectively simulated all the photoelectron spectral bands. Eventually, the theoretical findings conformed well with available experimental observations, highlighting the nonadiabatic effects among the closely situated spectral bands.

Computational Design of (B)Chl Models: Structural and Chemical Modifications toward Enriched Properties.

The functional units of natural photosynthetic systems control the process of converting sunlight into chemical energy. In this article, we explore a series of chemically and structurally modified bacteriochlorophyll and chlorophyll pigments through computational chemistry to evaluate their electronic spectroscopy properties. More specifically, we use multiconfigurational and time-dependent density functional theory methods, along with molecular dynamics simulations, to compute the models' energetics both in an implicit and explicit solvent environment. Structural modifications aimed at reducing the planarity of the macrocycle through alkyl-bridge anchoring reveal the significant role of the curvature in fine-tuning spectral properties, which mimics protein scaffold effects on naturally occurring pigments. Furthermore, chemical substitutions with a carbonyl group show potential for expanding absorption spectra toward the blue region, while incorporating an additional double bond decreases absorption efficiency. These insights lay the groundwork to design novel synthetic pigments, with potential applications in artificial light-harvesting systems and more efficient photovoltaic devices.

Optimal vibration control with considering non-probabilistic time-dependent reliability for hypersonic vehicles

Hypersonic vehicles have complex structures with multiple sources of uncertainties, and the presence of uncertainties may lead to the vehicles’ structural failure. Aiming to ensure the flight safety and structural reliability of a hypersonic vehicle, this study proposes a vibration optimization control method based on non-probabilistic time-dependent reliability. Due to the complex structure of the vehicle, its forebody and aftbody are modeled as two cantilever beams with the center of mass of the vehicle as the fixed fulcrum, respectively, and a vibration control model of cantilever is derived. Considering that the uncertainties in practical engineering are not easy to be counted, the uncertain parameters are quantified by using interval variables, and the dynamic response and time-dependent reliability of the uncertain system are analyzed based on the subinterval method and the non-probabilistic time-dependent reliability analysis method (NTRAM) designed in this paper. Further, to ensure the high reliability of the vehicle, an optimal robust linear quadratic regulator (ORLQR) method with the constraint of time-dependent reliability is proposed. The analysis of the numerical examples shows that the parameter uncertainty has a certain effect on the reliability of the vehicle, and verifies that the proposed ORLQR method can effectively control the vibration and slow down the reliability decline.

Many-Body Effects in a Composite Bosonic Josephson Junction

In standard bosonic Josephson junctions (BJJs), particles tunnel between two single-well potentials linked by a finite barrier. The dynamics of standard BJJs have been extensively studied, both at the many-body and mean-field levels of theory. In the present work, we introduce the concept of a composite BJJ. In a composite BJJ, particles tunnel between two double-well potentials linked by a finite potential barrier between them. We focused on the many-body facets of quantum dynamics and investigate how the complex structure of the junction influences the tunneling. Employing the multiconfigurational time-dependent Hartree method for bosons, highly accurate many-boson wavefunctions were obtained, from which properties were computed. We analyzed the dynamics using the survival probability, the degree of fragmentation of the junction, and the fluctuations of the observables, and discuss how the many-boson tunneling behaved, and how it may be controlled, using the composite nature of the junction. A central result of this work relates to the degree of fragmentation of composite BJJs with different numbers of bosons. We provide strong evidence that a universal degree of fragmentation into multiple time-dependent modes takes place. Further applications are briefly discussed.

State-to-State Time-Dependent Quantum Dynamics Studies of the Si(3P) + OH(X 2Π) → OSi(X 1Σg+) + H(2S) Reaction Based on a New HOSi(X2A') Potential Energy Surface.

Quantum and quasi-classical dynamics calculations were conducted for the reaction of Si with OH on the latest potential energy surface (PES), which is obtained by fitting tens of thousands of ab initio energy points by using the many-body expansion formula. To obtain an accurate PES, all energy points calculated with aug-cc-pVQZ and aug-cc-pV5Z basis sets were extrapolated to the complete basis set limit. The accuracy of our new PES was verified by comparing the topographic characteristics and contour maps of potential energy with other works. In addition, the anharmonic vibrational frequencies of HOSi and HSiO based on the present ab initio and PES by means of quantum dynamics methods were calculated. Dynamics information such as reaction probability, integral cross sections (ICS), product distribution, and rate constants was obtained on the new HOSi(X2A') PES. The dynamic information calculated using the quasi-classical trajectory method and time-dependent wave packet method is generally in good agreement, except for the vibrational state-resolved ICSs of product. The calculated differential cross section and capture time reveal that the reaction is primarily governed by the complex formation mechanism.

Enhancing optical absorbance and accelerating rotational speed in molecular motors through oriented external electric fields

Accelerating the rotational speed of light-driven molecular motors is among the foremost concerns in molecular machine research, as this speed directly influences the performance of a motor. Controlling the motor’s rotation is crucial for practical applications, and using an oriented external electric field (OEEF) represents a feasible method to achieve this objective. We have investigated the impact of an OEEF on the optical and kinetic properties of a novel π-donor/acceptor di-substituted molecular motor, R2,3-(NH2, CHO). We employed density functional theory (DFT) and time-dependent DFT methods to analyze the electronic excitation and thermal isomerization behavior. Our results demonstrate that the absorption wavelength, absorption efficiency of the motor, and rate constant of the thermal isomerization reaction can be adjusted by applying OEEFs, which are predictable based on the dipole moment and polarizability of the molecules under consideration. In particular, we observed a shift in the absorption wavelength toward longer ranges, an enhancement in light absorption intensity, and an acceleration in the rotation rate when applying a weak positive directional external electric field to the R2,3-(NH2, CHO) motor. In summary, this theoretical study highlights the potential of OEEFs for improving the performance of molecular motors.

A quantum investigation of kinetic isotope effects in the Ne + HD[formula omitted](v=0) [formula omitted] NeH[formula omitted]/NeD[formula omitted] + D/H reaction

The exact quantum scattering calculations for the Ne + HD+(v = 0, j = 0) reaction on its electronic ground state have been performed using the time-dependent wave packet method at the state-to-state level. The reaction mechanisms and intramolecular isotope effects have been investigated and analyzed in terms of integral reaction cross section, product internal state distributions and differential cross sections in the 0.4–1.2 eV collision energy interval. Results from the present calculations show that the products NeH+ and NeD+ are associated to different values of the total angular momentum, J. Competing reaction mechanisms that correlate with low and high J values show different preferences for products.

Vibrational ladder climbing dissociation of LiH molecules excited by non-chirped pulses

Vibrational ladder climbing (VLC) is one of the advanced methods for achieving molecular dissociation, usually requires the use of chirped laser pulses to adapt to the change of energy difference between molecular vibrational levels. In this work, a scheme is proposed for using non-chirped pulses to couple the vibrational rotational levels of excited state to realize VLC dissociation of LiH molecules in the excited state. The first pulse induces population excitation to the excited state A1Σ+, while the second pulse is used to drive the excited state vibrational levels population up step by step until dissociation occurs. The non-chirped pulse VLC dissociation dynamics is investigated using the time-dependent quantum wave packet theory method. The “”climb steps” process for excited state molecules at low full width at half maximum (FWHM) of the second laser pulse is demonstrated. The frequency has an obvious influence on the distribution of excited state vibrational rotational levels and further affects the relaxation process of the undissociated part and the angular distribution of dissociation products. It is also explained that the anomalous decrease of dissociation probability is caused by vibrational levels oscillation.

The importance of boundary evolution for solar-wind modelling

The solar wind is a continual outflow of plasma and magnetic field from the Sun’s upper atmosphere—the corona—that expands to fills the solar system. Variability in the near-Earth solar-wind conditions can produce adverse space weather that impacts ground- and space-based technologies. Consequently, numerical fluid models of the solar wind are used to forecast conditions a few days ahead. The solar-wind inner-boundary conditions are supplied by models of the corona that are, in turn, constrained by observations of the photospheric magnetic field. While solar eruptions—coronal mass ejections (CMEs)—are treated as time-dependent structures, a single coronal “snapshot” is typically used to determine the ambient solar-wind for a complete model run. Thus, all available time-history information from previous coronal-model solutions is discarded and the solar wind is treated as a steady-state flow, unchanging in the rotating frame of the Sun. In this study, we use 1 year of daily-updated coronal-model solutions to comprehensively compare steady-state solar-wind modelling with a time-dependent method. We demonstrate, for the first time, how the SS approach can fundamentally misrepresent the accuracy of coronal models. We also attribute three key problems with current space-weather forecasting directly to the steady-state approach: (1) the seemingly paradoxical result that forecasts based on observations from 3-days previous are more accurate than forecasts based on the most recent observations; (2) high inconsistency, with forecasts for a given day jumping significantly as new observations become available, changing CME propagation times by up to 17 h; and (3) insufficient variability in the heliospheric magnetic field, which controls solar energetic particle propagation to Earth. The time-dependent approach is shown to alleviate all three issues. It provides a consistent, physical solution which more accurately represents the information present in the coronal models. By incorporating the time history in the solar wind along the Sun-Earth line, the time-dependent approach will provide improvements to forecasting CME propagation to Earth.

Detection of a Planar Tetracoordinate Hydrogen within the Indium Framework by Quantum Dynamics Theory.

In this work, we consider the question how to detect the planar tetracoordination hydrogen geometry which was recently proposed by electronic structure calculations on the In4H+ system (Angew. Chem. Int. Ed. 2024, 63, e202317312; e202400927; e202403214). Keeping the C4v symmetry, a two-dimensional model of In4H+ is designed to build the nonadiabatic Hamiltonian operator with the lowest-lying singlet and triplet states coupled with spin-orbit coupling. The electronic energies in fitting the potential energy matrix are computed at either the MRCI or CCSD (T) level. Having constructed Hamiltonian, the multiconfigurational time-dependent Hartree product method predicts vibrational eigenstates for spectrum and recrossing probability of the proton. These quantum dynamics calculations predict a period of ∼60 fs for the proton recrossing the In4 moiety and further indicate that experimental observation of the D4h geometry for the triplet state is highly probable at room temperature even though the present MRCI and previous CASPT2 calculations (Angew. Chem. Int. Ed. 2024, 63, e202400927) both predict the C4v symmetry. To measure the C4v geometry, a low temperature of ≲30 K could be adopted. Despite the low temperature, the experiment might still miss the C4v geometry due to the nonzero recrossing probability of H at the low kinetic energy region. Further, a new type of hydrogen bonding in the D4h geometry is proposed to explain the interaction between the C4v geometries.

A Time-Dependent Inclusion-Based Method for Continuous Collision Detection between Parametric Surfaces

Continuous collision detection (CCD) between parametric surfaces is typically formulated as a five-dimensional constrained optimization problem. In the field of CAD and computer graphics, common approaches to solving this problem rely on linearization or sampling strategies. Alternatively, inclusion-based techniques detect collisions by employing 5D inclusion functions, which are typically designed to represent the swept volumes of parametric surfaces over a given time span, and narrowing down the earliest collision moment through subdivision in both spatial and temporal dimensions. However, when high detection accuracy is required, all these approaches significantly increases computational consumption due to the high-dimensional searching space. In this work, we develop a new time-dependent inclusion-based CCD framework that eliminates the need for temporal subdivision and can speedup conventional methods by a factor ranging from 36 to 138. To achieve this, we propose a novel time-dependent inclusion function that provides a continuous representation of a moving surface, along with a corresponding intersection detection algorithm that quickly identifies the time intervals when collisions are likely to occur. We validate our method across various primitive types, demonstrate its efficacy within the simulation pipeline and show that it significantly improves CCD efficiency while maintaining accuracy.