Exploring the Aromaticity Differences of Isoelectronic Species of Cyclo[18]carbon (C18), B6C6N6, and B9N9: The Role of Carbon Atoms as Connecting Bridges.

The cyclo[18]carbon (C18) has piqued widespread interest in recent years for its geometrical aesthetic and unique electronic structure. Inspired by it, theoretical investigations of its isoelectronic B9N9 have been published occasionally; however, few studies considered their other companion B6C6N6. In this work, we study the geometric structure, charge distribution, bonding characteristic, aromaticity, and electron delocalization of B6C6N6 and B9N9 for the first time and compare the relevant results with those of C18. Based on the comprehensive analysis of aromaticity indicators such as AV1245, nucleus-independent chemical shifts, anisotropy of the induced current density, magnetically induced current density, iso-chemical shielding surface, and induced magnetic field (Bind), we found that B6C6N6 has definitely a double aromatic character similar to C18 and the aromaticities of the two are very close, while B9N9 is a nonaromatic species. In response to this novel finding, we delved into its nature from an electron delocalization perspective through a localized orbital locator, electron localization function, Fermi hole, and atomic remote delocalization index analyses. The C atom between B and N as an interconnecting bridge strengthens the electron delocalization of the conjugate path, which is the essence of the significant enhancement of the molecular aromaticity from B9N9 to B6C6N6. This work elucidates that within the framework of the isoelectronicity of C18, different methods of atomic doping can achieve molecules with completely different properties.

Molecular assembly with a figure-of-eight nanohoop as a strategy for the collection and stabilization of cyclo[18]carbon.

The recently synthesized novel figure-of-eight nanohoop with two strained oligoparaphenylenes (OPPs) was theoretically designed to collect and stabilize new allotropic carbon cyclo[18]carbon (C18) through molecular assembly. The size adaptability and shape complementarity of C18 to OPP make it possible for them to combine into extraordinary ring-in-ring supramolecules. Thermodynamic analysis of 2C18@OPP showed that the host-guest complex should spontaneously form below 404 K. Molecular dynamics (MD) simulations demonstrated that the assembly of C18 and OPP into host-guest complexes of up to 1 : 2 can occur at ambient temperature. Various real-space function analyses revealed that the nature of the non-covalent interaction between C18 and OPP is the van der Waals (vdW) attraction characterized by π-π stacking. Photoexcitation makes the host-guest complexes less stable in their S1 state by causing the central linker to flatten.

The association of female reproductive factors with risk of metabolic syndrome in women from NHANES 1999-2018.

BACKGROUND: Female reproductive factors such as age at first birth (AFB), age at last birth (ALB), number of pregnancies and live births play an essential role in women's health. However, few epidemiological studies have evaluated the association between female reproductive factors and metabolic syndrome (MetS). We therefore conducted a cross-sectional study to investigate the association between MetS risk and female reproductive factors. METHODS: We investigated the relationship between AFB, ALB, number of pregnancies and live births and the incidence of MetS using publicly available data from the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2018. Weighted multivariable logistic regression analysis, restricted cubic spline (RCS) model, and subgroup analysis were used to evaluate the association between AFB and ALB and the risk of MetS in women. In addition, the relationship between the number of pregnancies, live births and MetS risk was also explored. RESULTS: A total of 15,404 women were included in the study, and 5,983 (38.8%) had MetS. RCS models showed an N-shaped relationship between AFB and MetS risk, whereas ALB, number of pregnancies, and live births were linearly associated with MetS. Weighted multivariable logistic regression analysis showed that the number of live births was associated with MetS risk, with ORs of 1.18 (95% CI: 1.04, 1.35) for women with ≥ 5 deliveries compared to women with ≤ 2 births. CONCLUSIONS: AFB was associated with the risk of MetS in an N-shaped curve in women. In addition, women with high live births have a higher incidence of MetS.

Quantum phases of Rydberg atoms on a frustrated triangular-lattice array.

The neutral atoms coupled to a highly excited Rydberg state on a two-dimensional triangular lattice are investigated by employing the density matrix renormalization group technique in the matrix product state form. The full ground-state phase diagram as a function of blockade radius and the detuning of the exciting laser is determined by the behavior of entanglement entropy. We find several quantum phases including stripe-ordered and symmetry-breaking density-wave-ordered phases featured with regular excitation patterns of different excitation densities ρ = 1/3, 1/4, and 1/7. In addition, a ρ = 2/3 ordered phase and an interesting "order-by-disorder" phase, which has been prepared experimentally, are also observed in this work. Our work provides an exploration of the possible quantum phases that can occur in a triangularly arrayed Rydberg system, and thus could be a faithful theoretical guide for further experimental research.

Design, Synthesis and Fungicidal Activity of N-(thiophen-2-yl) Nicotinamide Derivatives.

Based on the modification of natural products and the active substructure splicing method, a series of new N-(thiophen-2-yl) nicotinamide derivatives were designed and synthesized by splicing the nitrogen-containing heterocycle natural molecule nicotinic acid and the sulfur-containing heterocycle thiophene. The structures of the target compounds were identified through 1H NMR, 13C NMR and HRMS spectra. The in vivo bioassay results of all the compounds against cucumber downy mildew (CDM, Pseudoperonospora cubensis (Berk.et Curt.) Rostov.) in a greenhouse indicated that compounds 4a (EC50 = 4.69 mg/L) and 4f (EC50 = 1.96 mg/L) exhibited excellent fungicidal activities which were higher than both diflumetorim (EC50 = 21.44 mg/L) and flumorph (EC50 = 7.55 mg/L). The bioassay results of the field trial against CDM demonstrated that the 10% EC formulation of compound 4f displayed excellent efficacies (70% and 79% control efficacies, respectively, each at 100 mg/L and 200 mg/L) which were superior to those of the two commercial fungicides flumorph (56% control efficacy at 200 mg/L) and mancozeb (76% control efficacy at 1000 mg/L). N-(thiophen-2-yl) nicotinamide derivatives are significant lead compounds that can be used for further structural optimization, and compound 4f is also a promising fungicide candidate against CDM that can be used for further development.

Multipartite entanglement and quantum criticality of Rydberg atoms trapped in a two-dimensional optical lattice.

We investigate the multipartite entanglement and quantum criticality of neutral atoms on a two-dimensional square lattice, interacting via laser excitation to atom Rydberg states. It is found that the first derivative of residual entanglement with respect to detuning has peaks near the critical point, and corresponding critical behaviors are shown to obey conventional finite-sized scaling, from which we numerically determine the quantum critical point and the critical exponent of the associated correlation length. We also show that there is a sharp peak in the fidelity susceptibility near the critical point, and the critical exponent of the associated correlation length is obtained based on the finite size analysis.

Lactobacillus plantarum C88 protects against aflatoxin B1-induced liver injury in mice via inhibition of NF-κB-mediated inflammatory responses and excessive apoptosis.

BACKGROUND: Probiotics play an important role in the human and animal defense against liver damage. However, the protective mechanism of Lactobacillus plantarum C88 on chronic liver injury induced by mycotoxin remains unclear. RESULTS: In this study, the addition of L. plantarum C88 obviously ameliorated the increased contents of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), total cholesterol and triglyceride, the diminish contents of total protein and albumin in serum of mice challenged with AFB1. Simultaneously, L. plantarum C88 attenuated the inflammatory response via significantly reducing the levels of pro-inflammatory factors, including interleukin-1ß (IL-1ß), IL-6, IL-8, interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α) in serum. Furthermore, L. plantarum C88 remarkably down-regulated the nuclear factor kappa B (NF-κB) signaling pathways by weakening the expression of toll-like receptor 2 (TLR2) and TLR4, and inhibited NF-κB nuclear translocation through enhancing the expression of NF-κB inhibitor (IκB). Neutralization experiments confirmed that L. plantarum C88 decreased the levels of some pro-inflammatory factors due to the suppression of the NF-κB signaling pathways. Besides, L. plantarum C88 decreased the levels of Bax and Caspase-3, elevated the level of Bcl-2, and reduced mRNA expressions of Fatty acid synthetase receptor (Fas), FAS-associated death domain (FADD), TNF receptor associated death domain (TRADD) and Caspase-8 in the liver. CONCLUSIONS: Probiotic L. plantarum C88 prevented AFB1-induced secretion of pro-inflammatory cytokines by modulating TLR2/NF-κB and TLR4/NF-κB pathways. The molecular mechanisms of L. plantarum C88 in ameliorating AFB1-induced excessive apoptosis included regulating the mitochondrial pathway and cell death receptor pathways.

AgsA response to cadmium and copper effects at different temperatures in Escherichia coli.

Small heat shock proteins (sHsps), present from prokaryotes to eukaryotes, are a highly conserved molecular chaperone family. They play a crucial role in protecting organisms against cellular insults from single or multiple environmental stressors including heavy metal exposure, heat or cold shock, oxidative stress, desiccation, etc. Here, the toxicity of cadmium and copper, and their ability to modify the cellular growth rate at different temperatures in Escherichia coli cells were tested. Also, the response mechanism of the sHSP aggregation-suppressing protein (AgsA) in such multiple stress conditions was investigated. The results showed that the half effect concentration (EC50 ) of cadmium in AgsA-transformed E. coli cells at 37°C, 42°C, and 50°C were 11.106, 29.50, and 4.35 mg/L, respectively, and that of the control cells lacking AgsA were 5.05, 0.93, and 0.18 mg/L, respectively, while the half effect concentration (EC50 ) of copper in AgsA-transformed E. coli cells at 37°C, 42°C, and 50°C were 27.3, 3.40, and 1.28 mg/L, respectively, and that of the control cells lacking AgsA were 27.7, 5.93, and 0.134 mg/L, respectively. The toxicities of cadmium and copper at different temperatures as observed by their modification of the cellular growth rate and inhibitory effects were in a dose-dependent manner. Additionally, biochemical characterization of AgsA protein in cells subjected to cadmium and copper stresses at different temperatures implicated suppressed aggregation of cellular proteins in AgsA-transformed E. coli cells. Altogether, our data implicate the AgsA protein as a sensitive protein-based biomarker for metal-induced toxicity monitoring.

The response of larvae Brachymystax lenok during continuous and single pulses exposure to copper, zinc, lead and cadmium.

The continuous and single pulses exposure of Cu, Zn, Pb and Cd on larvae Brachymystax lenok were tested in this study. The first-order kinetics was employed to obtain better comprehension on the time-toxicity relationship of tested heavy metals in continuous exposure test. For difference in time-varying exposure or recovery, 50% lethal time-averaged concentration (TAC) was used to assess the pulsed toxicity, which took both time and concentration into consideration in exposure and post-exposure period. TAC assessment to the single pulses and the regression analysis of first-order kinetic to continuous exposures demonstrated that Cu and Zn showed greater toxicity than Pb and Cd, indicating a slower uptake and/or depuration effect for zinc or copper. Furthermore, the results showed that recovery effect of larvae to all four metals was found in 24 h exposure followed by 72 h in fresh water, while for 72 h exposure and 24 h non-exposure the delayed lethal phenomenon occurred.

Heterologous expression of AgsA enhances Escherichia coli tolerance to the combined effect of elevated temperature and Zinc toxicity.

Small heat shock proteins (sHSPs) are ubiquitous stress proteins that are able to protect the cells against cellular insults from temperature, heavy metal etc. However, the molecular chaperone roles of sHSPs in enhancing growth and adaptation under combined temperature and metal stresses in Escherichia coli cells have been poorly understood. Here, we analyze the function of recombinant AgsA, a small heat shock protein from Salmonella enterica serovar Typhimurium under combined temperature and zinc stress in E. coli. Our results show that the heterologous expression of AgsA significantly increases the tolerance of E. coli cells to the combined effect of temperature stress and zinc toxicity by maintaining the stability of soluble proteins. Furthermore, there was remarkable and significant difference in the half effect concentration (EC50) of zinc at all temperatures treatments in both test cells. The EC50s of zinc at 37 °C, 42 °C and 50 °C were 15.24 mg/L, 29.30 mg/L, and 5.98 mg/L respectively in the AgsA-transformed E. coli cells, and 3.03 mg/L, 2.38 mg/L, and 0.373 mg/L, respectively in the control cells lacking AgsA. Together, our data indicate a good concentration-response relationship between all three temperatures treatment and zinc toxicity in E. coli, and establish for the first time the combined effects of temperature and zinc toxicity on E. coli cells. Also, the AgsA protein response to combined thermal and metal stress could serve as a molecular biomarker for the assessment of interactive stress damage to the cells.

Determination of the neuropharmacological drug nodakenin in rat plasma and brain tissues by liquid chromatography tandem mass spectrometry: Application to pharmacokinetic studies.

A rapid and sensitive liquid chromatography tandem mass spectrometry detection using selected reaction monitoring in positive ionization mode was developed and validated for the quantification of nodakenin in rat plasma and brain. Pareruptorin A was used as internal standard. A single step liquid-liquid extraction was used for plasma and brain sample preparation. The method was validated with respect to selectivity, precision, accuracy, linearity, limit of quantification, recovery, matrix effect and stability. Lower limit of quantification of nodakenin was 2.0 ng/mL in plasma and brain tissue homogenates. Linear calibration curves were obtained over concentration ranges of 2.0-1000 ng/mL in plasma and brain tissue homogenates for nodakenin. Intra-day and inter-day precisions (relative standard deviation, RSD) were <15% in both biological media. This assay was successfully applied to plasma and brain pharmacokinetic studies of nodakenin in rats after intravenous administration.

The induction of metallothioneins during pulsed cadmium exposure to Daphnia magna: Recovery and trans-generational effect.

Although the importance of pulse exposure has gained ground in recent years, there were few studies on recovery and trans-generational effect of it. Two successive generations Daphnia magna were exposed to cadmium (Cd) pulses for 6h at the concentrations from 40 to 100 µg/l. The changes of tolerance and induction of MTs in exposed D. magna and their offspring were measured. The reduced tolerance of exposed D. magna was returned to levels similar to control after about 9 days in a generation. The level of MT still increased up to 3 days after exposure. In the experimental range, exposure duration played a decisive role in MT induction. The tolerance of F1 was lower than F0 and decreased with increasing pulsed concentrations of F0. Exposed to the same pulse, the MT levels of F1 were higher than the MT levels of F0, but the more obvious detoxification of MT in F1 had not been found. Our results suggest that pulsed cadmium exposure had impact on offspring of exposed organism and the risk assessment should take trans-generational effect into account.

The trans-generation effect during pulsed cadmium exposure: tolerance and induction of hsp70.

Although the importance of pulse exposure has gained ground in recent years, it still needs to be better evaluated and understood. Two successive generations of Daphnia magna were exposed to four concentrations (40, 60, 80 and100µgCdl(-1)) of 6h cadmium (Cd) pulses. The increase of pulsed concentration of parent generation (F0) led to the decrease of EC50 and an increase of 21-day cumulative mortality of the first generation of offspring (F1). The mortality of F1 has a significantly higher level than F0 when they experienced the same pulse. Hsp70 can be induced by Cd pulse and gradually recover to the normal level after exposure. But the sensitivity of hsp70 of F1 was lower than F0 and the response seemingly was not under the control of heredity. Compared to growth, reproduction was more sensitive. The complete risk assessment of pulse exposure should take the response of offspring into account, especially in an ecological or field context.

Quantum phase transition in fiber-coupled quantum networks.

We explore the quantum criticality in a one-dimensional quantum network, where adjacent nodes are connected by a fiber and each node consists of a cavity doped with N two-level atoms. We investigate the phase diagrams for cases of different atom numbers on resonance by making use of the mean-field approximation and find that both the fidelity and entanglement entropy for the ground state have dramatic changes near the critical points. Finally, the photon population imbalance of adjacent cavities is analytically explored via the two-node quantum network as the forerunner of phase transition.

In vivo T-cell depletion with antithymocyte globulins improves overall survival after myeloablative allogeneic stem cell transplantation in patients with hematologic disorders.

To assess the effect of prophylactic treatment with antithymocyte globulin (ATG) on graft-versus-host disease (GvHD) in myeloablative transplant patients, we performed a meta-analysis of randomized and cohort studies. Medline, Embase, the Cochrane Controlled Trial Register and the Science Citation Index were searched for studies on ATG treatment in patients with hematologic disorders undergoing myeloablative transplantation. Four randomized controlled trials, six retrospective and one prospective cohort study were included, covering 1,549 patients. The summary hazard ratios (HRs) for overall survival were 0.84.

Precarious Employment and Subjective Career Success During the School-to-Work Transition.

Purpose: The transition from school to work is an important stage in the career development of university students, and precarious employment during this period can significantly impact their early career success. In today's unstable employment environment, this study examines how employment instability during the transition from school to work directly and indirectly affects college students' subjective career success. This contributes to a thorough understanding of this transitional period and provides university students with the necessary resources to cope with a smooth transition from school to work. Patients and Methods: We recruited senior students at five universities in Harbin, China, from May to July 2022. After obtaining participants' consent, questionnaires were distributed via social media, resulting in 967 valid questionnaires. Based on this sample, we examined the chain mediating effect of financial stress and occupational self-efficacy in the association between precarious employment and career success and the moderating effect of employability. Results: The study found that precarious employment hurts career success and can also affect career success by increasing financial stress and decreasing occupational self-efficacy among college students. At the same time, financial stress can also decrease students' self-efficacy. Finally, employability can reduce the adverse effects of precarious employment on career success and occupational self-efficacy. Conclusion: The link between employment instability and subjective career success during the transition from school to work has been demonstrated for university students. Employment instability not only increases college students' financial stress but also reduces career self-efficacy, which in turn affects college students' perceptions of early subjective career success. Importantly, employability plays a positive role in the smooth school-to-work transition and subjective career success of university students.

Effect of Final Thermomechanical Treatment on the Mechanical Properties and Microstructure of T Phase Hardened Al-5.8Mg-4.5Zn-0.5Cu Alloy.

The effect of final thermomechanical treatment (FTMT) on the mechanical properties and microstructure of a T-Mg32(Al Zn)49 phase precipitation hardened Al-5.8Mg-4.5Zn-0.5Cu alloy was studied. The as-cold rolled aluminum alloy samples were subjected sequentially to solid solution treatment, pre-deformation, and two-stage aging treatment. Vickers hardness was measured during the aging process under various parameters. Tensile tests were conducted on the representative samples based on the hardness results. Microstructural characteristics were analyzed via transmission electron microscopy and high-resolution transmission electron microscopy. The conventional T6 process was also carried out for comparison. The hardness and tensile strength are increased evidently by the FTMT process for the Al-Mg-Zn-Cu alloy, while the ductility is adversely affected to a small extent. The precipitation at the T6 state consists of a coherent Guinier-Preston zone and T″ phase in the form of intragranular, fine, and spherical particles, while a semi-coherent T' phase appears after the FTMT process as a new constituent. The distribution of dislocation tangles and isolated dislocations is another feature of FTMT samples. Enhanced precipitation hardening and dislocation strengthening account for the improved mechanical performance of FTMT samples.

Theoretical design of a dual-motor nanorotator composed of all-carboatomic cyclo[18]carbon and a figure-of-eight carbon hoop.

A novel supramolecular complex (2C18@OPP) constructed from two kinds of unique nanorings, all-carboatomic cyclo[18]carbon (C18) and figure-of-eight carbon hoop (OPP), has been studied theoretically from the perspective of an extraordinary dual-motor nanorotator. The rotational barrier of C18 in OPP is extremely small at ambient temperature, implying the possibility of the host-guest complex as an ultrafast nanorotator. The rotational characteristics and thermodynamic stability of the nanorotator at different temperatures were then explored. The rotational behaviors of the two C18 rings in OPP are basically independent of each other. The supramolecule investigated in this work is the first example of a dual-motor nanorotator that promises to be an important building block for constructing complicated molecular machines.

Two nucleotide sugar transporters are important for cell wall integrity and full virulence of Magnaporthe oryzae.

Cell wall polysaccharides play key roles in fungal development, virulence, and resistance to the plant immune system, and are synthesized from many nucleotide sugars in the endoplasmic reticulum (ER)-Golgi secretory system. Nucleotide sugar transporters (NSTs) are responsible for transporting cytosolic-derived nucleotide sugars to the ER lumen for processing, but their roles in plant-pathogenic fungi remain to be revealed. Here, we identified two important NSTs, NST1 and NST2, in the rice blast fungus Magnaporthe oryzae. Both NSTs were localized in the ER, which was consistent with a function in transporting nucleotide sugar for processing in the ER. Sugar transport property analysis suggested that NST1 is involved in transportation of mannose and glucose, while NST2 is only responsible for mannose transportation. Accordingly, deletion of NSTs resulted in a significant decrease in corresponding soluble saccharides abundance and defect in sugar utilization. Moreover, both NSTs played important roles in cell wall integrity, were involved in asexual development, and were required for full virulence. The NST mutants exhibited decreasing external glycoproteins and exposure of inner chitin, which resulted in activation of the host defence response. Altogether, our results revealed that two sugar transporters are required for fungal cell wall polysaccharides accumulation and full virulence of M. oryzae.