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In the approximate valence bond (VB) description of molecular electronic structures, the resonating VB effect might be incorporated in an efficient manner by mixing the triplet component into conventional singlet geminals. We developed a variational optimization scheme for this generalized pairing type wave function in the framework of the spin Hamiltonian model. With numerical verifications, we found the resonance stabilization is partially described through the contamination of higher spin states for molecules such as non-Kekulé hydrocarbons.

Theoretical and computational methods have proven powerful in capturing both the local and the global pictures of molecular self-assembly processes.

We evaluated the difficulty score of laparoscopic cholecystectomy (LC) for acute cholecystitis (AC) proposed in the Tokyo guidelines 2018 (TG18) and analyzed the most appropriate scoring method.We reviewed 127 patients who underwent LC for AC from January 2018 to March 2022. According to TG18, surgical difficulty was scored for five categories consisting of 25 intraoperative findings. The median, highest, and mean score of the five categories were analyzed for their association with surgical outcomes.The difficulty score distribution (0/1/2/3/4/5/6) was as follows: median (8/34/43/30/12/0/0), highest (1/1/32/42/36/15/0) and mean (19/49/49/10/0/0/0). In all three scoring methods, higher difficulty scores were significantly correlated with longer operative time, more blood loss, and higher occurrence of subtotal cholecystectomy in trend tests. The areas under the curve (AUCs) for prediction of prolonged operative time minutes and increased blood loss were similar in all three scoring methods. For conversion to subtotal cholecystectomy, the AUC was significantly better for the highest than median and mean score (p = .015 and p = .002, respectively).The difficulty score in TG18 appropriately reflects the surgical difficulty of LC for AC. The median, highest, and mean scores of the five categories are all available, and the highest scores are simple and versatile.

The human calcium-sensing receptor (CaSR) is a G protein-coupled receptor that maintains extracellular Ca

The NMR chemical shifts of hydride and fluoride ions in the solution phase are evaluated from the first principle. The cluster structure in the first solvation shell is calculated by density functional theory and MP2 theory, and the solvent effect around the cluster is considered by PCM and RISM-SCF-SEDD methods. The obtained shifts are analyzed in terms of electronic structure and solvent effects and are compared with available experimental data. The fluoride ion is deshielded in the presence of solvent molecules compared to the isolated state due to a larger paramagnetic contribution from the 2p orbital. On the other hand, there is no such change for the hydride ion. The paramagnetic and diamagnetic contributions are slightly changed due to the solvation, but they are canceled out. As a result, the chemical shift of the hydride ion is less affected by the solvent than that of the fluoride ion. The increased diamagnetic contribution of hydride ion dissolved in the solvent is attributed to the change in electron density coupled with microscopic solvation.

Curtin-Hammett principle works in a reaction sequence where slow irreversible reactions are connected to a fast reversible reaction and determines the product distribution depending only on the relative energy barriers of the two irreversible reactions, resulting in kinetic pathway selection. A basic question is whether Curtin-Hammett principle is applicable to reaction networks composed of reversible elementary reactions, though reversible reactions are generally governed by the laws of thermodynamics. Numerical simulations of model systems where reversible elementary reactions are connected linearly to an initial reversible reaction demonstrate that a metastable state far from equilibrium is transiently produced and that its lifetime is prolonged with increasing the number of connected reversible reactions. Pathway selection based on this extended concept of Curtin-Hammett principle was observed in molecular self-assembly of a Pd6L4 truncated tetrahedron, which supports the idea that the extended Curtin-Hammett principle is a key general concept underlining kinetic control in reversible reaction networks.

Supramolecular polymer networks were constructed via in situ polymerization using host-guest-mediated homoternary system in water. Photo- and temperature-responsive properties can exhibit tailored viscoelasticity.

PDMS thimble was the key to combining incompatible reactions to achieve deracemization of 1-phenylethanols in high yield with high optical yield.

QASAP and NASAP reveal that the macrocyclization faster than the bridging reaction in the intermediate leads to the Pd6L3 coordination prisms, while kinetically trapped species are produced when the bridging reaction takes place faster.

We investigated the mechanism of photoisomerization of stilbene via triplet state with para-benzoquinone sensitizer using the density functional theory and proposed a photocatalyst behavior of para-benzoquinone.

Background In the field of neuroscience, neural modules and circuits that control biological functions have been found throughout entire neural networks. Correlations in neural activity can be used to identify such neural modules. Recent technological advances enable us to measure whole-brain neural activity with single-cell resolution in several species including Caenorhabditis elegans. Because current neural activity data in C. elegans contain many missing data points, it is necessary to merge results from as many animals as possible to obtain more reliable functional modules. Results In this work, we developed a new time-series clustering method, WormTensor, to identify functional modules using whole-brain activity data from C. elegans. WormTensor uses a distance measure, modified shape-based distance to account for the time delay and the mutual inhibition of cell-cell interactions and applies the tensor decomposition algorithm multi-view clustering based on matrix integration using the higher orthogonal iteration of tensors (HOOI) algorithm (MC-MI-HOOI), which can estimate both the weight to account for the reliability of data from each animal and the clusters that are common across animals. Conclusions We applied the method to 24 individual C. elegans and successfully found some known functional modules. Compared with a widely used consensus clustering method to aggregate multiple clustering results, WormTensor showed higher silhouette coefficients. Our simulation also showed that WormTensor is robust to contamination from noisy data. WormTensor is freely available as an R/CRAN package https://cran.r-project.org/web/packages/WormTensor.

Recent development of large-scale activity imaging of neuronal ensembles provides opportunities for understanding how activity patterns are generated in the brain and how information is transmitted between neurons or neuronal ensembles. However, methodologies for extracting the component properties that generate overall dynamics are still limited. In this study, the results of time-lapse 3D imaging (4D imaging) of head neurons of the nematodeC. eleganswere analyzed by hitherto unemployed methodologies.By combining time-delay embedding with independent component analysis, the whole-brain activities were decomposed to a small number of component dynamics. Results from multiple samples, where different subsets of neurons were observed, were further combined by matrix factorization, revealing common dynamics from neuronal activities that are apparently divergent across sampled animals. By this analysis, we could identify components that show common relationships across different samples and those that show relationships distinct between individual samples.We also constructed a network model building on time-lagged prediction models of synaptic communications. This was achieved by dimension reduction of 4D imaging data using the general framework gKDR (gradient kernel dimension reduction). The model is able to decompose basal dynamics of the network. We further extended the model by incorporating probabilistic distribution, resulting in models that we call gKDR-GMM and gKDR-GP. The models capture the overall relationships of neural activities and reproduce the stochastic but coordinated dynamics in the neural network simulation. By virtual manipulation of individual neurons and synaptic contacts in this model, information flow could be estimated from whole-brain imaging results.

Urinary retention (UR) is a frequent complication following laparoscopic colorectal surgery. The aim of the present study was to investigate the risk factors for acute UR after laparoscopic surgery for colorectal cancer in patients receiving epidural analgesia. A retrospective study was conducted of 201 patients who underwent laparoscopic surgery for colorectal cancer among those receiving epidural analgesia. Univariate and multivariate analyses were performed to determine the clinicopathological factors associated with acute UR. Acute UR was defined as Clavien-Dindo classification grade ≥ 1. The overall incidence of acute UR was 17.9% (36/201). The univariate analysis showed that male gender (P = 0.043), a history of chronic heart failure (P = 0.009), an increased level of serum creatinine (P = 0.028), an increased intraoperative fluid volume (P = 0.016), and an early postoperative date of urinary catheter removal (P = 0.003) were both associated with acute UR. The multivariate logistic regression analysis revealed an increased intraoperative fluid volume (100-ml increments; odds ratio [OR]: 1.085, 95% confidence interval [CI]: 1.034–1.138, P

A precise understanding of the interfacial structure and dynamics is essential for the optimal design of various electrochemical devices. Herein, we propose a method for classical molecular dynamics simulations to deal with electrochemical interfaces with polarizable electrodes under the open circuit condition. Less attention has been given to electrochemical circuit conditions in computation despite being often essential for a proper assessment, especially comparison between different models. The present method is based on the chemical potential equalization principle, as is a method developed previously to deal with systems under the closed circuit condition. These two methods can be interconverted through the Legendre transformation so that the difference in the circuit conditions can be compared on the same footing. Furthermore, the electrode polarization effect can be correctly studied by comparing the present method with conventional simulations with the electrodes represented by fixed charges, since both of the methods describe systems under the open circuit condition. The method is applied to a parallel-plate capacitor composed of platinum electrodes and an aqueous electrolyte solution. The electrode polarization effects have an impact on the interfacial structure of the electrolyte solution. We found that the difference in circuit conditions significantly affects the dynamics of the electrolyte solution. The electric field at the charged electrode surface is poorly screened by the nonequilibrium solution structure in the open circuit condition, which accelerates the motion of the electrolyte solution.

Nitration of benzene is a representative aromatic substitution reaction related to the σ-complex (arenium ion or “Wheland” intermediate) concept. This reaction is typically carried out in a mixed acid solution to generate nitronium ions, and how solvent molecules play roles in the reaction has been of great interest. Here we will shed new light on the reaction, namely the electronic structure and the microscopic insights of the solvation, which have been rarely discussed so far. We studied this process using the reference interaction site model-self consistent field with constrained spatial electron density distribution (RISM-SCF-cSED) method, considering sulfuric acid or water molecules as a solvent. In this method, the electronic structure of the solute and the solvation structure are self-consistently determined based on quantum chemistry and statistical mechanics of molecular liquids. The solvation free energy surfaces in solution and solvation structures were verified. In the bond formation process of benzene and nitronium ions, the solvation structure by sulfuric acid molecules drastically changes and the solvation effect on the free energy is quite large. We revealed largely contributing resonance structures in the π-electron system of the σ-complex in gas and solution phases by analysing the valence electronic structures.

Memory-related neuronal responses are often elicited by sensory stimuli that recapitulate previous experience. Despite the importance of this sensory input processing, its underlying mechanisms remain poorly understood. Caenorhabditis elegans chemotax towards salt concentrations experienced in the presence of food. The amphid sensory neurons ASE-left and ASE-right respond to increases and decreases of ambient salt concentration in opposite manners. AIA, AIB and AIY interneurons are post-synaptic to the ASE pair and are thought to be involved in the processing of salt information transmitted from ASE. However, it remains elusive how the responses of these interneurons are regulated by stimulus patterns. Here we show that AIY interneurons display an experience-dependent response to gradual salt concentration changes but not to abrupt stepwise concentration changes. Animals with AIY intact (but AIA and AIB ablated) chemotax towards low salt concentrations similarly to wild-type animals after cultivation with low salt. ASE neurons transmit salt information about the environment through glutamatergic signaling, directing the activity of the interneurons AIY that promote movement towards favorable conditions.

Evaluation of electrochemical properties of cathodes of alkali-ion batteries in good agreement with experimental measurements, while avoiding empirical fitting is a highly desirable goal in materia...

Chemical reaction dynamics in solution are closely related to solvation dynamics, and understanding solvent responses remains a crucial issue in chemistry and chemical biology. In this study, we experimentally and computationally investigated the solvation dynamics along different solvation coordinates of the same molecule: the electronically excited state and ground state of the p-aminophenylthiyl radical generated by the photodissociation of bis(p-aminophenyl)disulfide. Time profiles of the peak shifts from the transient absorption and emission spectra after photodissociation were extracted to discuss the solvent reorganization process in various ionic liquids (ILs) with different viscosities. The absorption peak position of the radical followed common solvation dynamics, shifting to a lower energy with time due to reorganization of the surrounding solvent molecules in response to the charge redistribution and molecular volume change caused by photodissociation. On the other hand, the emission band of the radical did not show a meaningful spectral shift with time. It was also found that the solvation time in the ground state was not strongly dependent on the solvent viscosity. These experimental results deviate from the conventional dynamic Stokes shift theory. To discuss the experimental results, non-equilibrium molecular dynamics simulations were conducted. The spectral shift obtained by MD simulations indicated the existence of a large solvation energy change and solvation dynamics around the radical after the photodissociation. On the other hand, the electronic excitation of the radical brought about a relatively smaller solvation energy change, especially at the long delay time after the photodissociation. These differences might be one of the reasons for the unique experimentally observed solvation dynamics.

Herein, we present a systematic computational model to study the electronic states and free energies of a self-assembled multi-metal complex series. By combining the previously developed model Hamiltonian approach for transition-metal complexes and the generalized Born model, the thermodynamics, optimized geometries, and electronic states of the [Pd12L24]24+ nanocage are revealed, together with [PdnLm]2n+ complex series. The effective model Hamiltonian is a theoretical method to obtain the d-electron wavefunction and potential energy including interaction energy between the transition-metal and ligands. In the present improvement, the electronic state on each transition-metal center is focused as a building unit and solved under the whole electronic field of the assembling system. We realize a reliable and systematic treatment of multi-transition-metal complexes with different sizes and charges. Consequently, our model could reproduce binding energies of the [PdnLm]2n+ complex series quantitatively as compared to density functional theory (DFT). Regarding free energy, we revealed that the assembling solute becomes unstable due to the electrostatic interaction, and effects of the solvent and counter anions mainly compensated it. Optimized geometries were also analysed. The local square-planar coordination structures around the palladium centres were characterized in the complex series. The relationships between the entire symmetrical geometries and the local coordination structures are also discussed. Finally, electronic structures of the [Pd12L24]24+ nanocage were well characterized as a single-determinant, where only dx2-y2 is unoccupied due to the ligand-field effect. We also found that the solvent polarized the electronic states of the Pd ions, whereas the counter anion suppressed the polarization. The present method realizes size-independent reliable and rapid computations, and therefore can be expected to further application studies on self-assembly dynamics.