Solvent Effect on Dative and Ionic Bond Strengths: A Unified Theory from Potential Analysis and Valence-Bond Computations.

Solvent molecules interact with a solute through various intermolecular forces. Here we employed a potential energy surface (PES) analysis to interpret the solvent-induced variations in the strengths of dative (Me3NBH3) and ionic (LiCl) bonds, which possess both ionic and covalent (neutral) characteristics. The change of a bond is driven by the gradient (force) of the solvent-solute interaction energy with respect to the focused bond length. Positive force shortens the bond length and increases the bond force constant, leading to a blue-shift of the bond stretching vibrational frequency upon solvation. Conversely, negative force elongates the bond, resulting in a reduced bond force constant and red-shift of the stretching vibrational frequency. The different responses of Me3NBH3 and LiCl to solvation are studied with valence bond (VB) theory, as Me3NBH3 and LiCl are dominated by the neutral covalent VB structure and the ionic VB structure, respectively. The dipole moment of an ionic VB structure increases along the increasing bond distance, while the dipole moment of a neutral covalent VB structure increases with the decreasing bond distance. The roles of the dominating VB structures are further examined by the geometry optimizations and frequency calculations with the block-localized wavefunction (BLW) method.

Research on molecular dynamics and electrical properties of high heat-resistant epoxy resins.

In order to prepare highly heat-resistant packaging insulation materials, in this paper, bismaleimide/epoxy resin (BMI/EP55) composites with different contents of BMI were prepared by melt blending BMI into amino tetrafunctional and phenolic epoxy resin (at a ratio of 5:5). The microstructures and thermal and electrical properties of the composites were tested. The electrostatic potential distribution, energy level distribution, and molecular orbitals of BMI were calculated using Gaussian. The results showed that the carbonyl group in BMI is highly electronegative, implying that the carbonyl group has a strong electron trapping ability. The thermal decomposition temperature of the composites gradually increased with the increase of BMI content, and the 20% BMI/EP55 composites had the highest heat-resistance index, along with a glass transition temperature (Tg) of >250 °C. At different test temperatures, with increase in the BMI content, the conductivity of epoxy resin composites showed a tendency to first decrease and then increase, the breakdown field strength showed a tendency to first increase and then decrease, and the dielectric constant was gradually decreased. Two trap centers were present simultaneously in the composites, where the shallow trap energy level is the deepest in 20% BMI/EP composites and the deep trap energy level is the deepest in 10% BMI/EP55 composites. Correspondingly, the 10% BMI/EP55 composite had a slower charge decay rate, while the 20% BMI/EP55 had a faster charge decay rate. In summary, the BMI/EP55 composites with high heat resistance and insulating properties were prepared in this study, which provided ideas for preparing high-temperature packaging insulating materials.

Enhanced thermal conductivity of epoxy resin by incorporating three-dimensional boron nitride thermally conductive network.

Packaging insulation materials with high thermal conductivity and excellent dielectric properties are favorable to meet the high demand and rapid development of third generation power semiconductors. In this study, we propose to improve the thermal conductivity of epoxy resin (EP) by incorporating a three-dimensional boron nitride thermally conductive network. Detailedly, polyurethane foam (PU) was used as a supporter, and boron nitride nanosheets (BNNSs) were loaded onto the PU supporter through chemical bonding (BNNS@PU). After immersing BNNS@PU into the EP resin, EP-based thermally conductive composites were prepared by vacuum-assisted impregnation. Fourier transform infrared spectrometer and scanning electron microscope were used to characterize the chemical bonding and morphological structure of BNNS@PU, respectively. The content of BNNS in BNNS@PU/EP composites was quantitatively analyzed by TGA. The results show that the thermal conductivity of the BNNS@PU/EP composites reaches 0.521 W/m K with an enhancement rate η of 30.89 at an ultra-low BNNS filler content (5.93 wt. %). Additionally, the BNNS@PU/EP composites have excellent dielectric properties with the frequency range from 101 to 106 Hz. This paper provides an interesting idea for developing high thermal conductivity insulating materials used for power semiconductor packaging.

Reverse Designing the Wavelength-Specific Thermally Activation Delayed Fluorescent Molecules Using a Genetic Algorithm Coupled with Cheap QM Methods.

Genetic algorithm (GA) optimization coupled with the semiempirical intermediate neglect of differential overlap (INDO)/CIS method is presented to inversely design the red thermally activation delayed fluorescent (TADF) molecules. According to the predefined donor-acceptor (DA) library to build an ADn-type TADF candidate, we utilized the chemical notation language SMILES code to generate a TADF molecule and apply the RDKit program to produce the initial 3D molecular structure. A combined fitness function is proposed to evaluate the performance of the functional-lead TADF molecule. The fitness function includes three key parameters, i.e., the emission wavelength, the energy gap (ΔEST) between the lowest singlet (S1)- and triplet (T1)-excited states, and the oscillator strengths for electron transition from S0 and S1. A cheap QM method, i.e., INDO/CIS, on the basis of an xTB-optimized molecular geometry is applied to quickly calculate the fitness function. Finally, the GA approach is utilized to globally search for the wavelength-specific TADF molecules under our predefined DA library, and the optimum 630 nm red and 660 nm deep red TADF molecules are inversely designed according to the evolution of molecular fitness functions.

hsa-miR-875-5p inhibits tumorigenesis and suppresses TGF-ß signalling by targeting USF2 in gastric cancer.

BACKGROUND: Gastric cancer (GC) is one of the most common malignancies, and an increasing number of studies have shown that its pathogenesis is regulated by various miRNAs. In this study, we investigated the role of miR-875-5p in GC. METHODS: The expression of miR-875-5p was detected in human GC specimens and cell lines by miRNA qRT-PCR. The effect of miR-875-5p on GC proliferation was determined by Cell Counting Kit-8 (CCK-8) proliferation and 5-ethynyl-2'-deoxyuridine (EdU) assays. Migration and invasion were examined by transwell migration and invasion assays as well as wound healing assays. The interaction between miR-875-5p and its target gene upstream stimulatory factor 2(USF2) was verified by dual luciferase reporter assays. The effects of miR-875-5p in vivo were studied in xenograft nude mouse models. Related proteins were detected by western blot. RESULTS: The results showed that miR-875-5p inhibited the proliferation, migration and invasion of GC cells in vitro and inhibited tumorigenesis in vivo. USF2 was proved to be a direct target of miR-875-5p. Knockdown of USF2 partially counteracted the effects of miR-875-5p inhibitor. Overexpression of miR-875-5p could inhibit proliferation, migration and invasion and suppress the TGF-ß signalling pathway by downregulating USF2. CONCLUSIONS: MiR-875-5p can inhibit the progression of GC by directly targeting USF2. And in the future, miR-875-5p is expected to be a potential target for GC diagnosis and treatment.

Association between 5-hydroxytryptamine gene polymorphism rs140700 and primary insomnia in Chinese population.

BACKGROUND: Primary insomnia is a worldwide problem and it has a considerable negative impact on one's physical and mental health. Studies have shown that non-synonymous Single-nucleotide polymorphisms in 5-hydroxytryptamine (serotonin or 5-HT) are related to primary insomnia. Previous studies have shown that 5-HT polymorphism (rs140700) is related to depression, and insomnia is often accompanied by depression and anxiety. The relationship between this site and primary insomnia is unknown. We speculated that this site may be related to primary insomnia, so we investigated the relationship between rs140700 and primary insomnia. AIMS: To explore the relationship between the 5-HT gene polymorphism rs140700 and primary insomnia. METHODS: In this study, we included 57 patients with primary insomnia and 54 age- and gender-matched normal controls. The subjects who belonged to the Chinese population were subjected to polysomnography for three consecutive nights. Their sleep quality was assessed, and the genotypes of the 5-hydroxytryptamine (5-HT) gene polymorphism rs140700 were determined by the flight mass spectrometry. RESULTS: The genotype distributions of the 5-HT gene polymorphism rs140700 were in Hardy-Weinberg equilibrium in both patients and controls (P > 0.05). The allele and genotype distributions of this variant were comparable between the patients and controls in all subjects and between genders (all P > 0.05). The influence of rs140700 on percentage of stage 1 (P = 0.015) change and arousal index (P = 0.028) of primary insomnia was statistically significant. The logistic multi-factor regression analysis results revealed that 5-HT gene polymorphism rs140700 was not a risk factor for primary insomnia in the Chinese population (P = 0.589). CONCLUSIONS: The 5-HT gene polymorphism rs140700 may not be a susceptibility locus for primary insomnia in the Chinese population.

A Triptycene-Based Enantiopure Bis(Diazadibenzoanthracene) by a Chirality-Assisted Synthesis Approach.

By applying a chirality-assisted synthesis (CAS) approach enantiopure diaminodibromotriptycenes were converted to rigid chiral helical diazadibenzoanthracenes, which show besides pronounced Cotton effects in circular dichroism spectra higher photoluminescence quantum yields as comparable carbacyclic analogues. For the enantiopure building blocks, a protocol was developed allowing the large scale synthesis without the necessity of separation via HPLC.

Ruthenium-Catalyzed Reductive Arylation of N-(2-Pyridinyl)amides with Isopropanol and Arylboronate Esters.

A new three-component reductive arylation of amides with stable reactants (iPrOH and arylboronate esters), making use of a 2-pyridinyl (Py) directing group, is described. The N-Py-amide substrates are readily prepared from carboxylic acids and PyNH2 , and the resulting N-Py-1-arylalkanamine reaction products are easily transformed into the corresponding chlorides by substitution of the HN-Py group with HCl. The 1-aryl-1-chloroalkane products allow substitution and cross-coupling reactions. Therefore, a general protocol for the transformation of carboxylic acids into a variety of functionalities is obtained. The Py-NH2 by-product can be recycled.

Palladium-Catalyzed Asymmetric Allylic Allylation of Racemic Morita-Baylis-Hillman Adducts.

A palladium-catalyzed asymmetric allyl-allyl cross-coupling of acetates of racemic Morita-Baylis-Hillman adducts and allylB(pin) has been developed using a spiroketal-based bis(phosphine) as the chiral ligand, thus affording a series of chiral 1,5-dienes bearing a vinylic ester functionality in good yields, high branched regioselectivities, and uniformly excellent enantioselectivities (95-99 % ee). Further synthetic manipulations of the allylation products provided novel ways for rapid access to a range of chiral polycyclic lactones and polycyclic lactams, as well as the antidepressant drug (-)-Paroxetine, in high optical purities.

Spiroketal-based diphosphine ligands in Pd-catalyzed asymmetric allylic amination of Morita-Baylis-Hillman adducts: exceptionally high efficiency and new mechanism.

Exceptionally high activity (with a TON up to 4750) of the palladium complexes of SKP ligand was discovered in the catalysis of asymmetric allylic amination of MBH adducts with aromatic amines. A comprehensive mechanistic study indicates that the unique structural features of the SKP ligand, with a long P···P distance in its solid-state structure, were favorable for allowing two P atoms to play a bifunctional role in the catalysis. Herein, one of the P atom forms a C-P σ-bond with the terminal carbon atom of allyl moiety as a Lewis base, and an alternative P atom coordinates to Pd atom. The cooperative action of organo- and organometallic catalysis discovered in the present catalytic system is most likely responsible for its high activity, as well as excellent regio- and enantioselectivities. The mechanism disclosed in the present catalytic system is distinct from most of the currently recognized mechanisms for Pd-catalyzed allylic substitutions.

Rapid Estimation of fwhm for OLED Emission Spectra Using Bond-Length and Bond-Order Alterations.

Color purity is crucial for achieving a high-quality organic light-emitting diode. An essential property for evaluating color purity is the full width at half-maximum (fwhm) of emission spectra. Theoretically estimating fwhm requires the detailed knowledge of vibronic coupling constants for all vibrational modes, which is time-consuming to obtain via quantum mechanical calculations, particularly for optimizing the geometry of the lowest singlet excited state. These calculations pose a bottleneck for high-throughput screening of narrowband emitters. To address this challenge, we propose a simple model to assess the reorganization energy based on the relationship between bond-length alteration (ΔBL) and vertical bond-order alteration (ΔBO) in optimized ground-state structures. Additionally, a one-mode model is employed to rapidly and effectively estimate fwhm. Our new model yields results comparable to experimental data and more accurate theoretical approaches based on vibronic coupling constants of all vibrational modes but with significantly lower computational costs. This model holds promise for the virtual screening of narrowband emitter candidates.

A novel multi-scale network intrusion detection model with transformer.

Network is an essential tool today, and the Intrusion Detection System (IDS) can ensure the safe operation. However, with the explosive growth of data, current methods are increasingly struggling as they often detect based on a single scale, leading to the oversight of potential features in the extensive traffic data, which may result in degraded performance. In this work, we propose a novel detection model utilizing multi-scale transformer namely IDS-MTran. In essence, the collaboration of multi-scale traffic features broads the pattern coverage of intrusion detection. Firstly, we employ convolution operators with various kernels to generate multi-scale features. Secondly, to enhance the representation of features and the interaction between branches, we propose Patching with Pooling (PwP) to serve as a bridge. Next, we design multi-scale transformer-based backbone to model the features at diverse scales, extracting potential intrusion trails. Finally, to fully capitalize these multi-scale branches, we propose the Cross Feature Enrichment (CFE) to integrate and enrich features, and then output the results. Sufficient experiments show that compared with other models, the proposed method can distinguish different attack types more effectively. Specifically, the accuracy on three common datasets NSL-KDD, CIC-DDoS 2019 and UNSW-NB15 has all exceeded 99%, which is more accurate and stable.

Multicolor Emission in o-Carborane Derivatives Induced by Conformation Diversity through C-C Double Bond Substitution.

Rationally designed molecules with versatile conformations are ideal candidates for creating challenging single component-based multicolor emissive materials. Herein, a new strategy is presented by introducing a C-C double bond in an o-carborane derivative. Compared to a linear connection using a C-C triple bond (CbPyY), a C-C double bond connection (CbPyE) exhibited a zigzag structure and unique fluorescence behavior. Yellow, yellowish orange, and red crystals or films of CbPyE can be obtained, while only orange ones of CbPyY were achieved under the same condition. Single crystal XRD and theoretical calculation studies revealed the zigzag structure brings asymmetry to one arm of CbPyE, which causes conformation diversity and leads to the multicolor emission. Interestingly, different emissions showed different responses to acetone vapor; the yellow one showed much higher sensitivity and faster response than the other two. It is believed that the prepared materials and the proposed strategy would contribute to future advances in single-fluorophore-based multicolor emissive materials.

Exhaustive Exploitation of Nature-Inspired Computation for Cancer Screening in an Ensemble Manner.

Accurate screening of cancer types is crucial for effective cancer detection and precise treatment selection. However, the association between gene expression profiles and tumors is often limited to a small number of biomarker genes. While computational methods using nature-inspired algorithms have shown promise in selecting predictive genes, existing techniques are limited by inefficient search and poor generalization across diverse datasets. This study presents a framework termed Evolutionary Optimized Diverse Ensemble Learning (EODE) to improve ensemble learning for cancer classification from gene expression data. The EODE methodology combines an intelligent grey wolf optimization algorithm for selective feature space reduction, guided random injection modeling for ensemble diversity enhancement, and subset model optimization for synergistic classifier combinations. Extensive experiments were conducted across 35 gene expression benchmark datasets encompassing varied cancer types. Results demonstrated that EODE obtained significantly improved screening accuracy over individual and conventionally aggregated models. The integrated optimization of advanced feature selection, directed specialized modeling, and cooperative classifier ensembles helps address key challenges in current nature-inspired approaches. This provides an effective framework for robust and generalized ensemble learning with gene expression biomarkers.

Decoupling the air sensitivity of Na-layered oxides.

Air sensitivity remains a substantial barrier to the commercialization of sodium (Na)-layered oxides (NLOs). This problem has puzzled the community for decades because of the complexity of interactions between air components and their impact on both bulk and surfaces of NLOs. We show here that water vapor plays a pivotal role in initiating destructive acid and oxidative degradations of NLOs only when coupled with carbon dioxide or oxygen, respectively. Quantification analysis revealed that reducing the defined cation competition coefficient (η), which integrates the effects of ionic potential and sodium content, and increasing the particle size can enhance the resistance to acid attack, whereas using high-potential redox couples can eliminate oxidative degradation. These findings elucidate the underlying air deterioration mechanisms and rationalize the design of air-stable NLOs.

A novel series colorimetric and off-on fluorescent chemosensors for Fe3+ based on rhodamine B derivative.

A novel series colorimetric and off-on fluorescent chemosensors (2a, 2b, 2c) were designed and synthesized, which showed reversible and highly selective and sensitive recognition toward Fe(3+) over other examined metal ions. Upon addition of Fe(3+), sensors (2a, 2b) exhibit remarkably and 2c exhibits moderate enhanced absorbance intensity and color change from colorless to pink in CH(3)OH-H(2)O(1:1, v/v). The three compounds (2a, 2b, 2c) may therefore be applicable as rhodamine-based turn-on type fluorescent chemosensors.

Perfect absorption based on a ceramic anapole metamaterial.

Metamaterials, from concept to application level, is currently a high-trending topic. Due to the strict requirements of the simultaneous reasonable structural design and stability of materials, the construction of a high-performance metamaterial for extreme environments is still difficult. Here, combining metamaterial design with materials optimization, we propose a completely different strategy and synthesize a type of monomeric ceramic meta-atom to construct metamaterials. Based on a geometric design with multiple degrees of freedom and dielectric properties, hybrid anapole modes with impedance matching can be produced, experimentally inducing nearly perfect absorption with high temperature stability (high tolerable temperature of approximately 1300 °C, with almost zero temperature drift) in microwave/millimeter-wave bands. We surpass the oxidation temperature limitation of 800 °C in conventional plasmonic absorbers, and provide an unprecedented direction for the further development of integrated high-performance metamaterial wireless sensors responding to extreme environmental scenarios, which will also lead to a new direction of specific ceramic research toward device physics.

scEFSC: Accurate single-cell RNA-seq data analysis via ensemble consensus clustering based on multiple feature selections.

With the development of next-generation sequencing technologies, single-cell RNA sequencing (scRNA-seq) has become one indispensable tool to reveal the wide heterogeneity between cells. Clustering is a fundamental task in this analysis to disclose the transcriptomic profiles of single cells and is one of the key computational problems that has received widespread attention. Recently, many clustering algorithms have been developed for the scRNA-seq data. Nevertheless, the computational models often suffer from realistic restrictions such as numerical instability, high dimensionality and computational scalability. Moreover, the accumulating cell numbers and high dropout rates bring a huge computational challenge to the analysis. To address these limitations, we first provide a systematic and extensive performance evaluation of four feature selection methods and nine scRNA-seq clustering algorithms on fourteen real single-cell RNA-seq datasets. Based on this, we then propose an accurate single-cell data analysis via Ensemble Feature Selection based Clustering, called scEFSC. Indeed, the algorithm employs several unsupervised feature selections to remove genes that do not contribute significantly to the scRNA-seq data. After that, different single-cell RNA-seq clustering algorithms are proposed to cluster the data filtered by multiple unsupervised feature selections, and then the clustering results are combined using weighted-based meta-clustering. We applied scEFSC to the fourteen real single-cell RNA-seq datasets and the experimental results demonstrated that our proposed scEFSC outperformed the other scRNA-seq clustering algorithms with several evaluation metrics. In addition, we established the biological interpretability of scEFSC by carrying out differential gene expression analysis, gene ontology enrichment and KEGG analysis. scEFSC is available at https://github.com/Conan-Bian/scEFSC.

Role of transcribed ultraconserved regions in gastric cancer and therapeutic perspectives.

Gastric cancer (GC) is the fourth leading cause of cancer-related death. The occurrence and development of GC is a complex process involving multiple biological mechanisms. Although traditional regulation modulates molecular functions related to the occurrence and development of GC, the comprehensive mechanisms remain unclear. Ultraconserved region (UCR) refers to a genome sequence that is completely conserved in the homologous regions of the human, rat and mouse genomes, with 100% identity, without any insertions or deletions, and often located in fragile sites and tumour-related genes. The transcribed UCR (T-UCR) is transcribed from the UCR and is a new type of long noncoding RNA. Recent studies have found that the expression level of T-UCRs changes during the occurrence and development of GC, revealing a new mechanism underlying GC. Therefore, this article aims to review the relevant research on T-UCRs in GC, as well as the function of T-UCRs and their regulatory role in the occurrence and development of GC, to provide new strategies for GC diagnosis and treatment.

[Analysis of related factors in secondary erythrocytosis of obstructive sleep apnea hypopnea syndrome in Gansu province].

Objective:To analyze the related factors of secondary erythrocytosis of obstructive sleep apnea（OSA） in Gansu province. Methods:Polysomnography recording and analysis from January 2013 to January 2021, A total of 448 OSA patients of long-resident Han nationality in Gansu province. Hemoglobin（Hb） values were divided into group A（Hb 120-160 g/L） 41 cases, B（Hb 161-179 g/L） 142 cases, C（Hb 180-199 g/L） 152 cases, D（Hb 200-219 g/L） 79 cases, and E（Hb ≥220 g/L） 30 cases. General clinical data, altitude of residence, disease course, apnea hypopnea index （AHI）, and Lowest oxyhemoglobin（LSpO2） were compared among these groups. Multivariate regression and ROC curves were used to analyze the influencing factors of OSA secondary erythrocytosis. Results:There were no significant differences in age, sex, and course of disease among groups A, B, C, D, and E （P>0.05）.The altitude of group E was higher than that of groups A, B, C, and D （P<0.05）, but there was no significant difference between groups A, B, C and D （P>0.05）.AHI was significantly different among groups A, B, C, D, and E （P<0.05）, groups C, D, and E were significantly higher than A; group D was significantly higher than B, C.LSpO2 was significantly different among groups A, B, C, D, and E （P <0.05）, groups B, C, D, and E was significantly lower than A; group D, E was significantly lower than B, C.MSpO2 was significantly different among groups A, B, C, D, and E （P<0.05）, groups B, C, D, and E was significantly lower A; groups D, E was significantly lower than B , C.Multivariate regression showed that the higher the altitude, the lower the MSpO2, the more serious the secondary hyperhemoglobinemia.Age, course of the disease, AHI, and LSpO2 were not the influencing factors of OSA secondary hemoglobin increase.The areas under the ROC curve for MSpO2 and altitude to predict Hb≥180 g/L were 0.694（P<0.001） and 0.570（P=0.009）, with statistically significant differences（Z=3.205, P=0.001）. Conclusion:Altitude and MSpO2 were independent risk factors for OSA secondary erythrocytosis; MSpO2 predicted that Hb≥180 g/L in OSA patients was better than altitude.