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The first-principles quantum chemical computations often scale as Nk (N = basis sets; k = 1–4 for linear scaling, Hartree–Fock or density functional theory methods), which makes the development of accurate pseudopotentials and efficient basis sets necessary ingredients in modeling of heavy elements such as lanthanides and actinides. Recently, we have developed 4f-in-core norm-conserving pseudopotentials and associated basis sets for the trivalent lanthanides [Lu et al., J. Chem. Theory Comput. 19, 82–96 (2023)]. In the present paper, we present a unified approach to optimize high-quality Gaussian basis sets for modeling and simulations of condensed-phase systems. The newly generated basis sets not only capture the low total energy and fairly reasonable condition number of overlap matrix of lanthanide-containing systems, but also exhibit good transferability and reproducibility. These advantages ensure the accuracy of the basis sets while avoiding linear dependency concern of atom-centered basis sets. The performance of the basis sets is further illustrated in lanthanide molecular and condensed-phase systems by using Gaussian-plane wave density functional approach of CP2K. These new basis sets can be of particular interest to model structurally complicated lanthanide molecules, clusters, solutions, and solid systems. [ABSTRACT FROM AUTHOR]

While main group elements have four valence orbitals accessible for bonding, quadruple bonding to main group elements is extremely rare. Here we report that main group element boron is able to form quadruple bonding interactions with iron in the BFe(CO)3- anion complex, which has been revealed by quantum chemical investigation and identified by mass-selected infrared photodissociation spectroscopy in the gas phase. The complex is characterized to have a B-Fe(CO)3- structure of C3v symmetry and features a B-Fe bond distance that is much shorter than that expected for a triple bond. Various chemical bonding analyses indicate that the complex involves unprecedented B≣Fe quadruple bonding interactions. Besides the common one electron-sharing σ bond and two Fe→B dative π bonds, there is an additional weak B→Fe dative σ bonding interaction. This finding of the new quadruple bonding indicates that there might exist a wide range of boron-metal complexes that contain such high multiplicity of chemical bonds.

Solution chemistry of actinide ions is critical to understanding the solvation behaviors and hydrolysis process. Using tetravalent thorium ion Th4+ as a representative example, we investigate the local structures and dynamic behaviors of hydrated Th4+ ions by ab initio molecular dynamics (AIMD) simulations using the recently developed norm-conserving pseudopotentials and basis sets optimized for actinides (J.-B. Lu et al., J. Chem. Theory Comput. 2021, 17, 3360–3371). AIMD simulations reveal two distinct solvation shells, with the first shell comprising 9 water molecules at approximately rTh–O = 2.50 Å and exhibiting a tricapped trigonal prism geometry. These conclusions are confirmed through metadynamics simulations and further structural analysis. AIMD simulations also show the slight effect of temperature and counterions on the structure of the solution. The structured solvation shells of the highly charged Th4+ ion with the specific geometry, distinct from the structure of liquid water, lead to corresponding structural changes in the hydrogen bond network in water. Additionally, beyond the solvent-shared ion pair (SIP) state observed in the unbiased AIMD simulations, the metadynamics simulations reconstruct a two-dimensional free energy surface that clearly indicates the potential stability of the contact ion pair (CIP) state in the system with Cl− as a counterion. The findings in this work provide insights into the solution chemistry of actinides and serve as a reference for studying other actinide solution systems. [ABSTRACT FROM AUTHOR]

Problem: Pregnancy complications such as spontaneous abortion, preeclampsia, and preterm birth persist, despite current interventions aimed at their prevention and treatment largely proving unsuccessful. Interleukin‐27 (IL‐27), composed of p28 and EBI3 subunits, binds to IL‐27R, which consists of gp130 and IL‐27Rα (also known as WSX‐1 or TCCR), and plays a pivotal role in tumor development and inflammation regulation. At the maternal‐fetal interface, IL‐27 expression has been detected in trophoblasts, endometrial stromal cells, and decidual cells. Abnormal levels of IL‐27/IL‐27R have been linked to adverse pregnancy outcomes, including spontaneous miscarriage, preeclampsia, and preterm birth. This review aims to explore the expression of IL‐27 at the maternal‐fetal interface and its signaling pathway, uncovering the complex role of IL‐27 in pregnancy complications. Method of Study: A comprehensive literature review was conducted using PubMed/Medline, Scopus, and Embase databases, analyzing studies on IL‐27 expression and its signaling pathways at the maternal‐fetal interface. The review focused on identifying the presence of IL‐27 in various cell types and linking abnormal IL‐27/IL‐27R expression to pregnancy complications such as spontaneous miscarriage, preeclampsia, and preterm birth. Discussion and Conclusion: IL‐27 plays a complex role at the maternal‐fetal interface, with abnormal expression linked to several pregnancy complications. These findings highlight the need for further research to elucidate IL‐27's mechanisms and develop targeted interventions. Future studies should aim to develop targeted interventions and improve therapeutic strategies for managing pregnancy complications. [ABSTRACT FROM AUTHOR]

In order to explore the drag reduction characteristics of different jet parameters in the bulb through pump, the bionic design was carried out for the shark gills, and the model of the bulb through the pump with a jet port at the front end of the bulb body was established, and the influence mechanism of the placement position, jet velocity and number of jet ports on the flow field of the bulb through the pump was studied by CFX. The results show that the near-wall main stream collides with the jet, and the axial momentum transmitted by the main stream to the jet weakens the axial velocity of the near-wall main stream. The radial momentum of the jet to the main stream increases the radial velocity of the near-wall mainstream, and lifts the near-wall high-velocity zone away from the bulb body, so that the near-wall medium and low velocity bands are widened, the high-velocity zone is contracted, and the wall shear stress is reduced. The calculation predicts that the drag reduction effect is up to 23.069%, the head is increased by 0.083 m, and the efficiency is increased by 1.729%, which can provide guidance for the optimal design and efficient operation of the bulb through-flow pump. [ABSTRACT FROM AUTHOR]

Precipitation is an important component in the climate system and plays a key role in water resources protection, drought and flood prevention. Innovation Trend Analysis (ITA) method, R/S method, maximum entropy spectrum analysis and wavelet analysis were used to study the evolution characteristics of the Yellow River Delta annual precipitation from 1954 to 2014. The results suggest that the precipitation series changed significantly and showed an overall downward trend, and may show an upward trend in the future, which is relatively strong. There are three-time scales of annual precipitation variation: 20-32a, 8-18a, and 3-6a. The quasi-27 year was the main oscillation period of the average annual precipitation in the Yellow River Delta, the secondary major period was 13 years, and the small-scale oscillation period was 5 years. Precipitation changed suddenly in 1980 and 2003. In contrast, there was no significant mutation point in 2002-2014.

Structural characterization of neutral water clusters is crucial to understanding the structures and properties of water, but it has been proven to be a challenging experimental target due to the difficulty in size selection. Here, we report the size-specific infrared spectra of confinement-free neutral water nonamer (H2O)9 based on threshold photoionization, using a tunable vacuum ultraviolet free-electron laser. Distinct OH stretch vibrational fundamentals in the 3200–3350 cm−1 region are observed, providing unique spectral signatures for the formation of an unprecedented (H2O)9 structure evolved by adding a ninth water molecule onto a hydrogen bond-unbroken edge of the (H2O)8 octamer with D2d symmetry. This nonamer structure coexists with the five previously identified structures that can be viewed as derived by inserting a ninth water molecule into a hydrogen bond-broken edge of the D2d/S4 octamer. These findings provide key microscopic information for systematic understanding of the formation and growth mechanism of dynamical hydrogen-bonding networks that are responsible for the structure and properties of condensed-phase water. [ABSTRACT FROM AUTHOR]

Structural characterization of neutral water clusters is crucial to understanding the structures and properties of water, but it has been proven to be a challenging experimental target due to the difficulty in size selection. Here, we report the size-specific infrared spectra of confinement-free neutral water nonamer (H2O)9 based on threshold photoionization, using a tunable vacuum ultraviolet free-electron laser. Distinct OH stretch vibrational fundamentals in the 3200–3350 cm−1 region are observed, providing unique spectral signatures for the formation of an unprecedented (H2O)9 structure evolved by adding a ninth water molecule onto a hydrogen bond-unbroken edge of the (H2O)8 octamer with D2d symmetry. This nonamer structure coexists with the five previously identified structures that can be viewed as derived by inserting a ninth water molecule into a hydrogen bond-broken edge of the D2d/S4 octamer. These findings provide key microscopic information for systematic understanding of the formation and growth mechanism of dynamical hydrogen-bonding networks that are responsible for the structure and properties of condensed-phase water. [ABSTRACT FROM AUTHOR]