Browse Articles

The predictive value of the vasoactive inotropic score in the postoperative treatment of patients suffering from infective endocarditis

Abstract The study aimed to analyze the predictive value of the vasoactive inotropic score (VIS) in the postoperative treatment of patients undergoing valve surgery for infective endocarditis (IE). At our institution, 334 patients underwent valve surgery for IE from 01/2016 to 12/2022. Patients with postoperative MCS device were excluded from this study. Data are presented as medians and 25th – 75th percentiles, or absolute numbers and percentages. Non-survivors had a significantly higher EuroSCORE II preoperatively (4.5 (2.3–9.8)% vs. 12.6 (5.7–20.9)%, p  < 0.001). In non-survivors, Staphylococcus (89 (32.1%) vs. 20 (54.1%), p  = 0.01) and Staphylococcus aureus (62 (22.4%) vs. 14(37.8%), p  = 0.064) were significantly more frequently identified as causative pathogens. Non-survivors had significantly higher IL-6 levels at POD 1, 2 and 4 compared to survivors ( p  < 0.021). Non survivor had significantly higher VIS immediately postoperatively as well as 6 h, 12 h, 24 h, 36 h and 48 h after surgery. In addition, VIS at 48 h was identified as an independent variable associated with non-survival at values > 4.1. When comparing the ROC of lactate, ScvO2 and VIS after 48 h, VIS showed the highest AUC. The VIS is particularly suitable for patients with infective endocarditis due to combined assessment of postoperative cardiovascular dysfunction and IE related inflammatory response. We provided suggestive evidence that the amount of cardiovascular support represented as the VIS has a predictive value regarding mortality in patients undergoing valve replacement for IE. In addition, VIS showed superiority compared to conventional scoring systems for predicting outcome in the intensive care of postoperative IE patients.

Implementing advanced trial wave functions in fermion quantum Monte Carlo via stochastic sampling

We introduce an efficient approach to implement correlated many-body trial wave functions in auxiliary-field quantum Monte Carlo (AFQMC). To control the sign/phase problem in AFQMC, a constraint is derived from an exact gauge condition but is typically imposed approximately through a trial wave function or trial density matrix, whose quality can affect the accuracy of the method. Furthermore, the trial wave function can also affect the efficiency through importance sampling. The most natural form of the trial wave function has been single Slater determinants or their linear combinations. More sophisticated forms, for example, with the inclusion of a Jastrow factor or other explicit correlations, have been challenging to use, and their implementation is often assumed to require a quantum computer. In this work, we demonstrate that a large class of correlated wave functions, written in the general form of multi-dimensional integrals over hidden or auxiliary variables times Slater determinants, can be implemented as a trial wave function by coupling the random walkers to a generalized Metropolis sampling. We discuss the fidelity of AFQMC with stochastically sampled trial wave functions, which are relevant to both quantum and classical algorithms. We illustrate the method and show that an efficient implementation can be achieved, which preserves the computational scaling of AFQMC. We test our method in molecules under bond stretching and in transition metal diatomics. Significant improvements are seen in both accuracy and efficiency over typical trial wave functions, and the method yields total ground-state energies systematically within chemical accuracy. The method can be useful for incorporating other advanced wave functions, for example, neural quantum state wave functions optimized from machine learning techniques, or for other forms of fermion quantum Monte Carlo.

A scalable cloud-integrated AI platform for real-time optimization of EV charging and resilient microgrid energy management

Photophysical properties of perylenebisimide derivatives studied by time-resolved transient optical and electron paramagnetic resonance spectroscopy

We studied the intersystem crossing (ISC) of the neutral, monoanionic, and dianionic forms of two perylenebisimide PBI derivatives with twisted π-conjugation framework in the molecular structure: one is substituted with four chloride atoms (PBI-Cl), whereas the other has a fused dimeric molecular structure (DiPBI). PBI-Cl is highly fluorescent, and no ISC was observed. However, the DiPBI shows efficient ISC (triplet state lifetime τT = 3.6 μs), supported by theoretical computation with the Herzberg–Teller effect taken into account. Time-resolved electron paramagnetic resonance spectra of the triplet state of DiPBI show that the zero field splitting (ZFS) D parameter is 778 MHz, indicating that the electron spin density is delocalized, because the ZFS D is much smaller than the triplet state of the unsubstituted PBI (D = 1303 MHz). No ISC was observed for the dianion [DiPBI]2−, whereas for [PBI-Cl]2, ISC was observed. This result infers that twisting of the π-conjugation framework of a molecular structure does not necessarily induce ISC, and excited state energy level matching of S1/Tn states may play the decisive role in ISC. These studies are helpful to fully exploit the super strong reductivity of photoexcited dianions in photocatalytic redox organic reactions due to the enhanced intermolecular electron transfer based on the long-lived triplet excited state of the dianions.

Mapping NK cell diversity in response to COVID-19 and mRNA vaccination

Structural evolution and superionic state of MnOOH under high-pressure and high-temperature

Hydrous minerals are essential for elucidating the mechanisms and forms of water storage in the Earth’s deep interior. Using crystal structure prediction and first-principles calculations, we identify a previously unreported Pbca-MnOOH phase that is both thermodynamically and dynamically stable in the 34–75 GPa pressure range. This structure consists of edge-sharing MnO6 octahedra, further linked via corner-sharing to form a three-dimensional framework. Electronic structure analysis indicates the coexistence of O–H covalent bonding and Mn–O ionic interactions, with the phase remaining semiconducting throughout the stability range. Ab initio molecular dynamics simulations reveal that Pbca-MnOOH enters a superionic state under high-pressure and high-temperature conditions relevant to the Earth’s geotherm. These results not only point to a possible mechanism for deep-Earth water transport but also provide critical insights into the pressure-induced structural and transport properties of Mn-bearing hydrous phases.

Octocoral dynamics over a decade on Florida’s coral reef

Abstract In recent decades, studies have documented increased octocoral cover and density on western Atlantic reefs, suggesting their potential to thrive in areas once dominated by scleractinians. On Florida’s Coral Reef (FCR), octocorals are among the most abundant benthic taxa, and octocoral cover has demonstrated resilience, despite frequent acute disturbances that have decimated scleractinian populations. While octocoral cover is an important metric, particularly when assessing broad patterns, it overlooks key demographic processes, such as recruitment and survival, that underpin resilience. This study explored the spatiotemporal trends in arborescent octocorals across FCR using three metrics: percent cover, density, and the recruit density of target species. Using a long-term dataset across FCR from 2013 to 2023, generalized mixed-effects models revealed that temporal variations occurred predominantly at regional habitat scales. Octocoral cover declined slightly in most habitats from 2013 to 2023 (1.67% overall), but density increased overall by 33.7%, indicating a shift in the community composition due to several disturbances during the study period. Recruit density surged in the latter half of the study, leading to an increase in density in some habitats that surpassed pre-disturbance levels. Even though octocoral density was quickly restored by abundant recruitment after these disturbances, successive years of growth and survival were still needed to attain a percent cover equal to pre-disturbance values. Marine heatwaves in 2014 and 2015 had minimal impacts on octocoral cover or density, whereas Hurricane Irma (2017) caused significant region-wide declines in both metrics. The combined effects of Hurricane Ian (2022) and the onset of the 2023 marine heatwave likely drove significant declines in cover and density of octocorals in the Florida Keys and Dry Tortugas at the end of the study period. These findings suggest that some species of octocorals demonstrate a remarkable resilience, with populations recovering rapidly through recruitment following acute disturbances across FCR habitats. This multi-metric approach provides a comprehensive framework for understanding octocoral dynamics and their responses to environmental stressors on FCR.

From DFT to compact non-local model: Accurate and efficient Hückel-based simulation of molecular electronic devices

The implementation of simple models similar to those used in semiconductor chip design can accelerate progress in molecular electronics. To elaborate a model of such type, we perform ab initio calculations of electron transport through polyene and polyphenylene molecular conductors under both zero and finite bias conditions, using various anchor groups (thiomethyl, pyridine, and benzo[b]thiophene) attached in both symmetric and asymmetric configurations. Based on the resulting transmission spectra, we propose a phenomenological Hückel Hamiltonian fitting model that is both accurate and relatively simple. This model remains consistent, as parameters extracted from symmetric anchor configurations at zero bias can be applied to asymmetric cases under both zero and finite bias conditions. We find that parameters related to the molecule–electrode interface (tunneling coupling and energy shift) are predominantly anchor-specific and show only weak dependence on the molecular conductor’s internal structure. In contrast, parameters describing the redistribution of charges along the molecule are of a non-local nature and demonstrate a strong dependence on intramolecular conduction. The proposed model, as well as the obtained numerical values of the parameters for common anchor groups, enables straightforward yet realistic studies of molecular electronic devices at the Hückel Hamiltonian level.

Unphysical solutions in coupled-cluster-based random phase approximation and how to avoid them

The direct ring coupled-cluster doubles (drCCD)-based random phase approximation (RPA) has provided an attractive framework for the development and application of RPA-related methods. However, a potential unphysical solution issue recently reported by Rekkedal et al., J. Chem. Phys. 139, 081101, (2013) has raised significant concerns regarding the general applicability of coupled-cluster-based RPA, particularly in small-gap systems where RPA is anticipated to outperform commonly employed second-order perturbation theory. In this work, we elucidate the underlying origin of the multi-solution issue in drCCD and develop both a practical criterion for validating drCCD solutions and improved preconditioners based on level shifting and regularized MP2 methods for stabilizing the iterative solution of the drCCD equation. We demonstrate the robustness and effectiveness of our approach through representative systems—including molecules with stretched bonds, large conjugated systems, and metallic clusters—where standard drCCD iteration encounters convergence difficulties. Furthermore, we extend our approach to various recently developed reduced-scaling drCCD-based RPA methods, thereby establishing a foundation for their stable application to large-scale problems. The extension of our approach to RPA with exchange, quasiparticle RPA, and particle–particle RPA is also discussed.

Correlations between ionic conductivity and co-solvent modulated water structure and dynamics in aqueous Zn-ion battery electrolytes

The addition of a co-solvent with a higher donor number than water in aqueous zinc ion (Zn2+) battery (AZIB) electrolyte systems is a promising approach to prevent Zn-dendrite formation and metal anode corrosion. We have investigated here how a co-solvent in an aqueous mixture affects both the structure and dynamics of water molecules that are engaged in solvating Zn2+ ions and whether the solution ionic conductivity constructs any correlation to the altered structure and dynamics of these solvating water molecules. For this purpose, we have considered an experimental AZIB system with tetramethylurea (TMU) as a co-solvent at several compositions. Molecular dynamics simulations have been performed to extract ionic conductivity using the Onsager transport coefficients, tetrahedral H-bond network, intermittent H-bond lifetimes, and residence times of water molecules surrounding Zn2+ ions. We have found that the water–water H-bond network and orientational structure are significantly perturbed due to the presence of Zn2+. Moreover, both the residence time and H-bond lifetime of the solvating water molecules increase in the presence of TMU. The average number of water–water H-bonds is found to be positively correlated to the simulated conductivity, while H-bond lifetimes and water residence times depict anti-correlation. These data suggest that water–water H-bonds surrounding Zn2+ ions critically determine the Zn2+ transport, whereas the increase in water–water H-bond lifetimes and water residence times reinforces the idea of vehicular transport for Zn2+ ions. This microscopic structural and dynamical information explains the role of TMU in this AZIB system and provides a microscopic explanation for the observed mundane viscosity dependence of ionic conductivity.

Coupling all-electron full-potential density functional theory with grid-based continuum embeddings

Recent advances in continuum embedding models have enabled the incorporation of solvent and electrolyte effects into density functional theory (DFT) simulations of material surfaces, significantly benefiting electrochemistry, catalysis, and other applications. To extend the simulation of diverse systems and properties, the implementation of continuum embedding models into the Environ library adopts a modular programming paradigm, offering a flexible interface for communication with various DFT programs. The speed and scalability of the current implementation rely on a smooth definition of the key physical properties of the atomistic system, in particular, of its electronic density. This has hindered the coupling of Environ with all-electron simulation packages, as the sharp electron density peaks near atomic nuclei are difficult to represent on regular grids. In this work, we introduce a novel smoothing scheme that transforms atom-centered electron densities into a regular grid representation while preserving the accuracy of electrostatic calculations. This approach enables a minimal and generic interface, facilitating seamless interoperability between Environ and all-electron DFT programs. We demonstrate this development through the coupling of Environ with the FHI-aims package and present benchmark simulations that validate the proposed method.

Optimal control on open quantum systems and application to non-Condon photoinduced electron transfer dynamics

In this work, we develop an optimal control theory on open quantum systems and their environments and exemplify the method with the application to the non-Condon photoinduced electron transfer in the condensed phase. This method utilizes the dissipaton theory, proposed by Yan in 2014 for open quantum systems, which provides an exact description of the dissipative system while also enabling rigorous characterization and control of environmental modes, fully taking into account the non-perturbative and non-Markovian effects. Leveraging the advantage of the dissipaton phase-space algebra, we present in this communication the theoretical strategy for optimal control of both system and environment simultaneously. The control protocol is successfully demonstrated on photoinduced electron transfer for the environment-targeted control facilitated transfer dynamics. This work sheds light on manipulating open systems dynamics via polarized environments.

Structure, dynamics, and electrochemistry of choline chloride/ethylene glycol eutectic solvents at an electrode surface explored by molecular dynamics simulations

Choline chloride and ethylene glycol mixtures with 1:2, 1:4, and 1:6 molar ratios on the surfaces of graphite and gold electrodes were studied using classical molecular dynamics simulations. Both neutral and charged electrodes were considered. The liquid composition, solvation structure, molecular orientation, and dynamics at the electrode surface are significantly different from those of the bulk liquid. These properties strongly depend on the electrode material and charge density, whereas they are less sensitive to the overall solvent composition. The effect of the electrode on the composition, structure, and orientation of the liquid fades beyond ∼10 Å from the surface of the electrode. This distance corresponds to about two layers of the structured solvent, despite the fact that the layered structure extends to at least five layers or about 25 Å. However, the electrode influences solvent dynamics over a longer distance. The electrochemical properties of the eutectic solvent at both electrode surfaces were also studied. The simulations captured the experimental differential capacitance shapes for both electrode systems, although the magnitudes and exact shapes differ. The simulations further revealed that the solvent in the first solvation layer can both overscreen and underscreen the electrode charges depending on the electrode material and electrode potential.

Learning the bulk and interfacial physics of liquid–liquid phase separation with neural density functionals

We use simulation-based supervised machine learning and classical density functional theory to investigate bulk and interfacial phenomena associated with phase coexistence in binary mixtures. For a prototypical symmetrical Lennard-Jones mixture, our trained neural density functional yields accurate liquid–liquid and liquid–vapor binodals together with predictions for the variation of the associated interfacial tensions across the entire fluid phase diagram. From the latter, we determine the contact angles at fluid–fluid interfaces along the line of triple-phase coexistence and confirm that there can be no wetting transition in this symmetrical mixture.

Regularized fluctuating lattice Boltzmann model

We introduce a regularized fluctuating lattice Boltzmann model (Reg-FLBM) for the D3Q27 lattice, which incorporates thermal fluctuations through Hermite-based projections to ensure compliance with the fluctuation–dissipation theorem. By leveraging the recursive regularization framework, the model achieves thermodynamic consistency for both hydrodynamic and ghost modes. Compared to the conventional single-relaxation-time BGK-FLBM, the Reg-FLBM provides improved stability and a more accurate description of thermal fluctuations. The implementation is optimized for large-scale parallel simulations on graphics processing unit-accelerated architectures, enabling systematic investigation of fluctuation-driven phenomena in mesoscale and nanoscale fluid systems.

Interplay of water film dewetting and hydrogen evolution on Pt(111): Insights from a machine-generated interatomic potential

The processes that determine the kinetics of hydrogen evolution reaction (HER) on metal surfaces remain a topic of discussion despite their long-standing importance in improving the efficiency of hydrogen generation. A major cause of this uncertainty is the extreme heterogeneity of the environment at the water–metal interface, which complicates the construction of simple models. To make progress, computationally efficient modeling methods need to be developed to handle the intricate nature of the water interface. In this paper, we use an implicit electrolyte approach suitable for ab initio dynamics, which allows the surface chemistry to be explicitly modeled with density functional theory while approximating the electrolyte with a continuum method. This approach incorporates ionic screening in the electrolyte via a Poisson–Boltzmann model, enabling the modeling of charged electrochemical interfaces in a dynamic, fluctuating environment. Our results qualitatively reveal a new factor that is likely important in understanding the HER: the location and structure of the interface where hydrogen is generated differ from where protons are exchanged between the water and metal. In particular, hydrogen is generated in regions where the water density is low (i.e., where the water film has dewetted from the substrate), while the adatom–water exchange reaction occurs in regions of high water density. Thus, the diffusion of hydrogen between these regions needs to be considered in the overall kinetics and may be a rate-limiting step.

Harnessing multi-mode optical structure for chemical reactivity

The prospect of controlling chemical reactivity using frequency-tunable optical microcavities has materialized over the past decade, evolving into a fascinating yet challenging new field of polaritonic chemistry, a multidisciplinary domain at the intersection of quantum optics, chemical dynamics, and non-equilibrium many-body physics. While most theoretical efforts to date have focused on single-mode cavities, practical implementations in polaritonic chemistry typically involve planar optical cavities that support a series of equally spaced photon modes, determined by the cavity geometry. In this work, we present a numerically exact, fully quantum-mechanical study of chemical reactions in few-mode cavities, revealing two key scenarios by which multi-mode effects can enhance cavity-modified reactivity. The first scenario emerges when the free spectral range is comparable to the single-mode Rabi splitting. In such cases, hybridization between a rate-decisive molecular vibration and a central resonant cavity mode reshapes the resonance landscape, enabling additional reaction pathways mediated by adjacent cavity modes. The second scenario exploits the intrinsic anharmonicity of molecular vibrations, which gives rise to multiple dipole-allowed transitions with distinct energies. Under multi-mode strong coupling, where different cavity modes individually resonate with these distinct transitions, multi-photon processes involving sequential absorption across multiple modes become accessible. This leads to a nontrivial and non-additive rate enhancement via a cascade-like vibrational ladder climbing process. Together, these findings offer new strategies for tailoring chemical reactivity by harnessing the structural richness of multi-mode structure, offering valuable insights for optimal experimental designs in polaritonic catalysis.

Improved terminal sliding mode control based on MPC for LIM applied to linear metro

Abstract To improve the dynamic response of the linear induction machine (LIM) over its complete speed range, this paper introduces a finite state-model predictive voltage control (FS-MPVC) based on terminal sliding mode control (TSMC). First, the TSMC for the speed loop is designed to attain high tracking capability and faster transient response. Second, in terms of the intricate balancing coefficient tuning difficulty and several computation steps of the conventional finite state-model predictive thrust control method, the control objectives are transformed to the primary voltage based on the FS-MPVC method. Furthermore, the TSMC-MPVC is fully studied in detail, covering its design and implementation steps. Ultimately, a 3 kW LIM has undergone comprehensive simulation evaluations by the presented TSMC-MPVC through comparing with the conventional methods at various speeds and loads to verify the effectiveness and viability of the proposed method.

A phylogeny for genus Capra based on extensive sampling of wild populations

Among the most economically and ecologically important taxa are those with wild and domestic counterparts, such as the true goats (genus Capra ), that are distributed and used by humans world-wide. Such taxa often played roles in the spread of pastoralism, farming, and modern societies. To advance understanding of the Capra , a relatively recent radiation across Eurasia, we generated one of the most complete taxonomic datasets for this genus to date. It includes 4603 bp of DNA sequence data for 11 nuclear loci from a broad geographic distribution of Capra , including 52 wild and 10 domestic individuals from nine species and 21 countries. All wild species were sampled in the wild (not in captivity). Results support the monophyly of recognized IUCN (International Union for Conservation of Nature) taxa, C. ibex , C. nubiana , C. pyrenaica , and C . sibirica while offering little support for the monophyly of C. aegagrus , C . falconeri , C. hircus , C. caucasica , or C. cylindricornis . We confirm wild goats ( C. aegagrus ) are the likely sole ancestor of domestic goats. This study bolsters and confirms prior studies, demonstrating the usefulness of multiple independent nuclear genes and widespread sampling of wild and domestic individuals for studies of taxa important to humans.

Equivalence of the FCSRT and RAVLT to detect medial Temporal lobe atrophy and tauopathy