Recent progress in atomically precise Ag/Cu-based hydride clusters

Owing to advantages in synthesis, separation, structure determination, and low cost (compared to noble metal nanoclusters), Ag/Cu hydride clusters (and their alloys) have received increasing research interest in recent decades and have shown great potential in mediating reduction reactions and H2 storage applications. The atomic precision of the Ag/Cu hydride clusters with the combination of single-crystal X-ray diffraction, 1/2H nuclear magnetic resonance, electrospray ionization mass spectrometry, density functional theory, and particularly, single-crystal neutron diffraction, has provided pivotal information regarding its structural characteristics, facilitating a deep understanding of the inherent bonding principles therein. This review summarizes the research progress of atomically precise Ag/Cu hydride clusters (and their alloys) over the past three years (2021–2023), mainly focusing on the synthesis, structure analysis, and catalytic applications of the hydride clusters. We believe that this review can benefit the future design of different types of metal hydride clusters and aid in their application in various redox reactions

Up-regulation of MiR-205 under hypoxia promotes epithelial-mesenchymal transition by targeting ASPP2

The epithelial–mesenchymal transition (EMT) is one of the crucial procedures for cancer invasion and distal metastasis. Despite undergoing intensive studies, the mechanisms underlying EMT remain to be completely elucidated. Here, we identified that apoptosis-stimulating protein of p53-2 (ASPP2) is a novel target of MiR-205 in various cancers. Interestingly, the binding site of MiR-205 at the 3′-untranslated region of ASPP2 was highly conserved among different species. An inverse correlation between MiR-205 and ASPP2 was further observed in vivo in cervical cancers, suggesting MiR-205 may be an important physiological inhibitor of ASPP2. Hypoxia is a hallmark of solid tumor microenvironment and one of such conditions to induce EMT. Notably, MiR-205 was remarkably induced by hypoxia in cervical and lung cancer cells. A marked suppression of ASPP2 was observed simultaneously. Further studies confirmed that hypoxia-induced ASPP2 suppression was mainly attributed to the elevated MiR-205. Interestingly, the alteration of MiR-205/ASPP2 under hypoxia was accompanied with the decreased epithelial marker E-cadherin and increased mesenchymal marker Vimentin, as well as a morphological transition from the typical cobblestone-like appearance to the mesenchymal-like structure. More importantly, MiR-205 mimics or ASPP2 silencing similarly promoted EMT process. By contrast, ASPP2 recovery or MiR-205 inhibitor reversed MiR-205-dependent EMT. Further studies demonstrated that the newly revealed MiR-205/ASPP2 axis promoted cell migration and also increased cell proliferation both in vivo and in vitro. These data together implicated a critical impact of MiR-205/ASPP2 on promoting EMT. MiR-205/ASPP2 may be potential diagnostic and therapeutic biomarkers in cervical and lung cancers

“Adjust Zang and arouse spirit” electroacupuncture ameliorates cognitive impairment by reducing endoplasmic reticulum stress in db/db mice

IntroductionDiabetic cognitive impairment (DCI) is a chronic complication of the central nervous system (CNS) caused by diabetes that affects learning and memory capacities over time. Recently, acupuncture has been shown to improve cognitive impairment in streptozotocin-induced diabetic rats. However, the effects of electroacupuncture on DCI and its underlying mechanism have not yet been elucidated in detail. MethodsIn this study, we used db/db mice as DCI animal models which showed low cognitive, learning and memory functions. Electroacupuncture significantly ameliorated DCI, which is reflected by better spatial learning and memory function using behavioral tests. The db/db mice with cognitive impairment were randomly divided into a model group (Mod) and an electroacupuncture treatment group (Acup), while db/m mice were used as a normal control group (Con). First, the mice were subjected to behavioural tests using the Morris water maze (MWM), and body weight, blood glucose, insulin, triglycerides (TG) and total cholesterol (TC) were observed; HE, Nissl, and TUNEL staining were used to observe the morphological changes and neuronal apoptosis in the mice hippocampus; Finally, Western blot and rt-PCR were applied to detect the essential proteins and mRNA of ERS and insulin signalling pathway, as well as the expression levels of Tau and Aβ.ResultsElectroacupuncture significantly ameliorated DCI, which is reflected by better spatial learning and memory function using behavioral tests. Moreover, electroacupuncture attenuated diabetes-induced morphological structure change, neuronal apoptosis in the hippocampus of db/db mice. Our results revealed that electroacupuncture could regulate the expression levels of Tau and Aβ by improving hippocampal ERS levels in db/db mice, inhibiting JNK activation, attenuating IRS1 serine phosphorylation, and restoring normal transduction of the insulin signaling pathway.DiscussionIn summary, ERS and insulin signaling pathway paly causal roles in DCI development. Electroacupuncture can significantly alleviate the pathogenesis of DCI, improve mice's learning and memory ability, and improve cognitive dysfunction. This study adds to our understanding of the effect of acupuncture on DCI and opens the door to further research on DCI

O-Abstraction Reactions of Nitrous Oxide with Cp2Ti(II) and Other Middle Transition Metal Complexes

DFT calculations have been carried out to study the detailed mechanisms of the O-abstraction reaction of N2O with Cp2Ti(II). The reaction is initiated by coordination of N2O to Cp2Ti via the N-end to form a linear N2O-coordinated species Cp2Ti(N2O), from which the metal center transfers one of its metal d electrons to one pi{*} orbital of the N2O ligand and gives a bent N2O-coordinated intermediate CP2Ti\_N-<-=N-O. The intermediate then reacts barrierlessly with another molecule Of Cp2Ti to form an N2O-bridged intermediate Cp2Ti\_N-<-=N-O-TiCp2, from which the singly oxo-bridged product (Cp2Ti)(2)O is formed with a release of N-2. Reactions of N2O with other middle transition metal complexes have also been calculated and discussed. General mechanisms for O-abstraction reactions of N2O with early and middle transition metal complexes have been provided

DFT studies on the mechanism of reactions between N2O and CP2M(eta(2)-alkyne) (M = Ti, Zr)

DFT calculations have been carried out to study the activation of N2O by the transition-metal alkyne complexes CP2M(eta(2)-alkyne) (M = Ti, Zr). The mechanism for the formation of the five-membered metallacyclic complexes CP2M(RC=CR'NN(O)), which were obtained directly from the reactions of N2O with the metal alkyne complexes, and the conversion of the five-membered metallacyclic complexes CP2M(RC=CR'NN(O)) via N-2 loss to the oxametallacyclobutene complexes CP2M(RC=CR'O) have been investigated in detail. An effort has been made to understand how the kinetically inert N2O can be activated. We concluded that N2O is best activated by metal fragments that possess high capability of :pi-back-bonding interactions with the pi{*} orbitals of N2O

Theoretical Investigations on Mechanisms of pd(OAC)(2)-Catalyzed Intramolecular Diaminations in the Presence of Bases and Oxidants

DFT Calculations have been carried out to study the mechanisms of Pd(OAc)(2)-catalyzed intramolecular diamination reactions in the presence of bases and oxidants. Oil the basis of the Calculation results, a mechanism involving an anti-aminopaladation/syn-C-sp3-N bond formation was proposed

Mechanism of Photocatalytic Cyclization of Bromoalkenes with a Dimeric Gold Complex

In recent years, dimeric gold complexes have been extensively used in photoredox reactions and have successfully mediated a series of traditionally challenging organic reactions. However, little is known about the function of the dimeric gold complexes in these reactions. In this study, we systematically studied the mechanism of the photocatalytic cyclization of bromoalkenes with the dimeric gold complex [Au₂(dppm)₂]²⁺ (dppm denotes bis­(diphenylphosphino)­methane). It is found that the dimeric gold complex acts as the radical initiator and terminator in this radical chain reaction. In the radical initiation step, the gold complex first promotes the electron transfer from amine to the bromoalkene substrate (via a reductive quenching mode) and then accepts the released bromide (from bromoalkene) to stabilize the reaction system. In the radical termination step, the dimeric gold complex mainly works as an unsynchronized bromine and electron donor. In the photocatalytic cyclization of bromoalkenes, the radical propagation step operates between the alkyl radical and the dehydrogenated amine radical. This study sheds light on the function of the dimeric gold complex in photoredox reactions and will hopefully benefit the future understanding of similar synthetic reactions

Two-population Asymmetric Evolutionary Game Dynamics-based Decision-making Behavior Analysis for A Supply-side Electric Power Bidding Market

This paper systematically discusses two-population asymmetric evolutionary games (2PAEGs) from the perspective of decision-making behavior characteristics, and applies these game models to a two-population supply-side electric power bidding market. First, a 2PAEG model is established. Then, complete evolutionary equilibrium rules of this model are revealed during decision-making processes. Discussion shows that final evolutionary game equilibria achieved in the 2PAEG model are only determined by some payoff parameters, which are defined as relative net payoff (RNP) parameters in this paper. Finally, a case study of supply-side bidding simulation for two generator populations is conducted, which can effectively verify the universality and effectiveness of the evolutionary dynamics results obtained in the established general 2PAEG model. Moreover, it shows that reasonable policies made by the government can guide more appropriate power bidding for onto-grid electricity