Mechanisms of polygalasaponin F against brain ischemia-reperfusion injury by targeting NKCC1.

Stroke is a serious threat to human health and current clinical therapies remain unsatisfactory. Elevated expression of Na-K-2Cl cotransporter 1 (NKCC1) following stroke can disrupt the blood-brain barrier (BBB) and result in brain edema, indicating that NKCC1 may be a potential therapeutic target for improving stroke outcomes. Polygalasaponin F (PGSF) is a triterpenoid saponin isolated from Polygala japonica Houtt, which has showed neuroprotective effects in previous studies.

On the nature of Co clusters reacting with water and oxygen.

Bulk cobalt does not react with water at room temperature, but cobalt nanometals could yield corrosion at ambient conditions. Insights into the cobalt cluster reactions with water and oxygen enable us to better understand the interface reactivity of such nanometals. Here we report a comprehensive study on the gas-phase reactions of Co clusters with water and oxygen.

Structures and bonding characteristics of KCl(H2O)n clusters with n = 1-10 based on density functional theory.

Aqueous inorganic salt solutions play a prominent role in both physiological and chemical experiments, and significant attention has been directed toward understanding the mechanisms underlying salt dissolution. In our effort to elucidate the hydration process of potassium chloride, we employed a comprehensive genetic algorithm to explore the structures of KCl(H2O)n (n = 1-10). A series of stable structures were identified by high-level ab initio optimization and single-point energy calculations with a zero-point energy correction.

Modulating the Oxygen Reduction Reaction Performance via Precisely Tuned Reactive Sites in Porphyrin-Based Covalent Organic Frameworks.

Covalent organic frameworks (COFs) have emerged as promising electrocatalysts due to their controllable architectures, highly exposed molecular active sites, and ordered structures. In this study, a series of porphyrin-based COFs (TAPP-x-COF) with various transition metals (Co, Ni, Fe) were synthesized via a facile post-metallization strategy under solvothermal synthesis. The resulting porphyrin-based COFs showed oxygen reduction reaction (ORR) activity with a trend in Co > Fe > Ni.

Structural and photoelectron spectroscopic study on the heterotrinuclear nickel-titanium dioxide carbonyl complexes NiTiO(CO) ( = 2-4).

Herein, the configurations and intrinsic electronic properties of heteronuclear transition metal dioxide carbonyl anions NiTiO(CO) ( = 2-4) in the gas phase were investigated using mass spectrometry coupled anionic photoelectron spectroscopy, calculations, and simulated density-of-state (DOS) spectra. The results clearly show that the binding of electrons is enhanced by the addition of CO. The ground state structures of NiTiO(CO) ( = 2-4) are characterized to show that three transition metal atoms (one Ti atom and two Ni atoms) forming a quasi-line is favored.

Ground-State Structures of Hydrated Calcium Ion Clusters From Comprehensive Genetic Algorithm Search.

We searched the lowest-energy structures of hydrated calcium ion clusters Ca(HO) ( = 10-18) in the whole potential energy surface by the comprehensive genetic algorithm (CGA). The lowest-energy structures of Ca(HO) clusters show that Ca is always surrounded by six HO molecules in the first shell. The number of first-shell water molecules changes from six to eight at = 12.

Inhibition of hypoxia inducible factor 1 by YC-1 attenuates tissue plasminogen activator induced hemorrhagic transformation by suppressing HMGB1/TLR4/NF-κB mediated neutrophil infiltration in thromboembolic stroke rats.

Hemorrhagic transformation (HT) is a frequent complication of ischemic stroke after thrombolytic therapy and seriously affects the prognosis of stroke. Due to the limited therapeutic window and hemorrhagic complications, tissue plasminogen activator (t-PA) is underutilized in acute ischemic stroke. Currently, there are no clinically effective drugs to decrease the incidence of t-PA-induced HT.

Spectroscopic Identification of Transition-Metal M[η-(O,O)C] Species for Highly-Efficient CO Activation.

The CO activation by transition metals is important in CO utilization but has proven to be challenging for experimental targets. Here we report first synthesis and spectroscopic characterization of transition-metal M[η-(O,O)C] species with bidentate double oxygen metal-CO coordination in the [ZrO(CO)] complexes. The Zr[η-(O,O)C] species yields a CO radical ligand, showing a high efficiency in CO activation.

Stability and NMR Chemical Shift of Amorphous Precursors of Methane Hydrate: Insights from Dispersion-Corrected Density Functional Theory Calculations Combined with Machine Learning.

Clathrate hydrates of natural gases are important backup energy sources. It is thus of great significance to explore the nucleation process of hydrates. Hydrate clusters are building blocks of crystalline hydrates and represent the initial stage of hydrate nucleation.

[Advances in molecular mechanisms of meiotic arrest and luteinizing hormone-induced meiotic resumption in oocytes].

Mammalian oocytes within Graafian follicles are arrested at prophase I of meiosis. C-type natriuretic peptide (NPPC), secreted by mural granulosa cells (MGCs), maintains oocyte meiotic arrest via binding to its cognate receptor natriuretic peptide receptor 2 (NPR2) and producing cyclic guanosine monophosphate (cGMP). NPR2 is most concentrated in the cumulus cells.

Distinguishing between halogenated alkanes containing the same halogen based on the reaction kinetic parameter using negative ion mobility spectrometry at atmospheric pressure.

Electron adsorption ionization ion mobility spectrometry can be used to detect halogen-containing volatile organic compounds with high sensitivity. However, this traditional electron attachment detection method cannot distinguish between volatile organic compounds containing the same halogen. For different organic compounds containing the same halogen, the product ions formed by the dissociation electron attachment process are the same.

Polygalasaponin F inhibits neuronal apoptosis induced by oxygen-glucose deprivation and reoxygenation through the PI3K/Akt pathway.

Cerebral ischaemia is a common cerebrovascular disease and often induces neuronal apoptosis, leading to brain damage. Polygalasaponin F (PGSF) is one of the components in Polygala japonica Houtt, and it is a triterpenoid saponin monomer. This research focused on anti-apoptotic effect of PGSF during oxygen-glucose deprivation and reoxygenation (OGD/R) injury in rat adrenal pheochromocytoma cells (PC12) and primary rat cortical neurons.

Hydrated Sodium Ion Clusters [Na(HO) ( = 1-6)]: An Study on Structures and Non-covalent Interaction.

Structural, thermodynamic, and vibrational characteristics of water clusters up to six water molecules incorporating a single sodium ion [Na(HO) ( = 1-6)] are calculated using a comprehensive genetic algorithm combined with density functional theory on global search, followed by high-level calculation. For ≥ 4, the coordinated water molecules number for the global minimum of clusters is 4 and the outer water molecules connecting with coordinated water molecules by hydrogen bonds. The charge analysis reveals the electron transfer between sodium ions and water molecules, providing an insight into the variations of properties of O-H bonds in clusters.

5-Aza-2'-deoxycytidine increases hypoxia tolerance-dependent autophagy in mouse neuronal cells by initiating the TSC1/mTOR pathway.

Background: Our previous study found that 5-Aza-2'-deoxycytidine (5-Aza-CdR) can repress the expression and activity of protein serine/threonine phosphatase-1γ (PP1γ) in mouse hippocampus. It is well known that PP1γ regulates cell metabolism, which is related to hypoxia/ischaemia tolerance. It has been reported that it can also induce autophagy in cancer cells.

Evolution of atomic structures of Sn, Sn , and SnCl clusters (N = 4-20): Insight from ab initio calculations.

An unbiased global search was employed to explore the low-energy structures of Sn, Sn , and SnCl clusters with N = 4-20 atoms based on the genetic algorithm combined with density functional theory calculations. Some unprecedented low-energy isomers are reported for Sn and SnCl clusters. The theoretical electronic properties such as binding energy per atom, ionization potential, adiabatic detachment energy, and vertical detachment energy compare well with the experimental data.

Cage fusion from bi-cages to tri-cages during nucleation of methane hydrate: a DFT-D simulation.

Water-cage clusters encapsulating guest molecules are the basic components of hydrate crystal structures. Herein, we investigated the fusion process from bi-cages to tri-cages to probe the nucleation mechanism at the initial stage of CH4 hydrate formation by employing dispersion-corrected density functional theory. We found that tri-cages possess high stability by sharing three, rather than two, polygonal faces.

Revisit the landscape of protonated water clusters H(HO) with n = 10-17: An ab initio global search.

Using a genetic algorithm incorporated with density functional theory, we explore the ground state structures of protonated water clusters H(HO) with n = 10-17. Then we re-optimize the isomers at B97-D/aug-cc-pVDZ level of theory. The extra proton connects with a HO molecule to form a HO ion in all H(HO) clusters.

Structures and Spectroscopic Properties of F(HO) with n = 1-10 Clusters from a Global Search Based On Density Functional Theory.

Using a genetic algorithm incorporated in density functional theory, we explore the ground state structures of fluoride anion-water clusters F(HO) with n = 1-10. The F(HO) clusters prefer structures in which the F anion remains at the surface of the structure and coordinates with four water molecules, as the F(HO) clusters have strong F-HO interactions as well as strong hydrogen bonds between HO molecules. The strong interaction between the F anion and adjacent HO molecule leads to a longer O-H distance in the adjacent molecule than in an individual water molecule.

Expression level of 12-amino acid triggering receptor on myeloid cells-like transcript 1 derived peptide alleviates lipopolysaccharide-induced acute lung injury in mice.

Acute lung injury (ALI) is a critical illness with a high morbidity and mortality rate due to severe inflammation in the lungs. The effects and underlying mechanism of the triggering receptor expressed on myeloid cells‑1 (TREM‑1)‑like transcript‑1‑derived peptide (LR12) on ALI remain unclear. The aim of the present study was to determine whether LR12 attenuates lipopolysaccharide (LPS)‑induced ALI and elucidate the mechanism underlying it.

Remote Limb Ischaemic Postconditioning Protects Against Myocardial Ischaemia/Reperfusion Injury in Mice: Activation of JAK/STAT3-Mediated Nrf2-Antioxidant Signalling.

Background: This study aimed to evaluate the protective effect and mechanisms of remote limb ischaemic postconditioning (RIPostC) against myocardial ischaemia/reperfusion (IR) injury.

Methods: Male mice underwent 45 min of coronary artery occlusion followed by 2 h of reperfusion. RIPostC was achieved by three cycles of 5 min of ischaemia and 5 min of reperfusion in the left hind limb at the start of the reperfusion period.

Which Density Functional Should Be Used to Describe Protonated Water Clusters?

Protonated water cluster is one of the most important hydrogen-bond network systems. Finding an appropriate DFT method to study the properties of protonated water clusters can substantially improve the economy in computational resources without sacrificing the accuracy compared to high-level methods. Using high-level MP2 and CCSD(T) methods as well as experimental results as benchmark, we systematically examined the effect of seven exchange-correlation GGA functionals (with BLYP, B3LYP, X3LYP, PBE0, PBE1W, M05-2X, and B97-D parametrizations) in describing the geometric parameters, interaction energies, dipole moments, and vibrational properties of protonated water clusters H(HO).

Diabetes blocks the cardioprotective effects of sevoflurane postconditioning by impairing Nrf2/Brg1/HO-1 signaling.

Sevofluane postconditioning (SPostC) protects heart against ischemia/reperfusion injury. However, SPostC cardioprotection is lost in diabetes whose cardiac heme oxygenase-1 (HO-1) is reduced. Brahma-related gene 1 (Brg1) facilitates nuclear factor-erythroid-2-related factor-2 (Nrf2) to activate HO-1 to increase myocardial antioxidant capacity in response to oxidative stress.

Structures, Stabilities, and Spectra Properties of Fused CH4 Endohedral Water Cage (CH4)m(H2O)n Clusters from DFT-D Methods.

In order to understand the cage fusion behavior during the nucleation processes of methane hydrate (MH), methane-encapsulated double-cage clusters (CH4)2(H2O)n (n = 30-43) and several multicage structures with three or more cages were studied employing DFT-D methods. We find that almost all the lowest-energy double-cage structures can be constructed by merging the most stable structures of the monocage clusters CH4(H2O)n (n = 18-24). Double-cage structures can achieve higher stability through sharing a hexagon than a pentagon, which may be applicable to larger fused cage clusters.

B28: the smallest all-boron cage from an ab initio global search.

Our ab initio global searches reveal the lowest-energy cage for B28, which is built from two B12 units and prevails over the competing structural isomers such as planar, bowl, and tube. This smallest boron cage extends the scope of all-boron fullerene and provides a new structural motif of boron clusters and nanostructures.