Direct flipping dynamics and quantized enrichment of chirality at single-molecule resolution.

Chirality is an important aspect of nature, and numerous macroscopic methods have been developed to understand and control chirality. For the chiral tertiary amines, their flexible flipping process makes it possible to achieve high chiral controllability without bond formation and breaking. Here, we present a type of stable chiral single-molecule devices formed by tertiary amines, using graphene-molecule-graphene single-molecule junctions. These single-molecule devices allow real-time, in situ, and long-time measurements of the flipping process of an individual chiral nitrogen center with high temporal resolution. Temperature- and bias voltage-dependent experiments, along with theoretical investigations, revealed diverse chiral intermediates, indicating the regulation of the flipping dynamics by energy-related factors. Angle-dependent measurements further demonstrated efficient enrichment of chiral states using linearly polarized light by a symmetry-related factor. This approach offers a reliable means for understanding the chirality's origin, elucidating microscopic chirality regulation mechanisms, and aiding in the design of effective drugs.

Real-Time Direct Monitoring of Chirality Fixation and Recognition at the Single-Molecule Level.

Chirality, a fundamental attribute of nature, significantly influences a wide range of phenomena related to physical properties, chemical reactions, biological pharmacology, and so on. As a pivotal aspect of chirality research, chirality recognition contributes to the synthesis of complex chiral products from simple chiral compounds and exhibits intricate interplay between chiral materials. However, macroscopic detection technologies cannot unveil the dynamic process and intrinsic mechanisms of single-molecule chirality recognition. Herein, we present a single-molecule detection platform based on graphene-molecule-graphene single-molecule junctions to measure the chirality recognition involving interactions between amines and chiral alcohols. This approach leads to the realization of in situ and real-time direct observation of chirality recognition at the single-molecule level, demonstrating that chiral alcohols exhibit compelling potential to induce the formation of the corresponding chiral configuration of molecules. The amalgamation of theoretical analyses with experimental findings reveals a synergistic action between electrostatic interactions and steric hindrance effects in the chirality recognition process, thus substantiating the microscopic mechanism governing the chiral structure-activity relationship. These studies open up a pathway for exploring novel chiral phenomena from the fundamental limits of chemistry, such as chiral origin and chiral amplification, and offer important insights into the precise synthesis of chiral materials.

Br, O-Modified Cu(111) Interface Promotes CO2 Reduction to Multicarbon Products.

Electrochemical reduction of CO2 to multicarbon (C2+) products with added value represents a promising strategy for achieving a carbon-neutral economy. Precise manipulation of the catalytic interface is imperative to control the catalytic selectivity, particularly toward C2+ products. In this study, a unique Cu/UIO-Br interface is designed, wherein the Cu(111) plane is co-modified simultaneously by Br and O from UIO-66-Br support. Such Cu/UIO-Br catalytic interface demonstrates a superior Faradaic efficiency of ≈53% for C2+ products (ethanol/ethylene) and the C2+ partial current density reached 24.3 mA cm-2 in an H-cell electrolyzer. The kinetic isotopic effect test, in situ attenuated total reflection Fourier transform infrared spectroscopy and density functional theory calculations have been conducted to elucidate the catalytic mechanism. The Br, O co-modification on the Cu(111) interface enhanced the adsorption of CO2 species. The hydrogen-bond effect from the doped Br atom regulated the kinetic processes of *H species in CO2RR and promoted the formation of *COH intermediate. The formed *COH facilitates the *CO-*COH coupling and promotes the C2+ selectivity finally. This comprehensive investigation not only provides an in-depth study and understanding of the catalytic process but also offers a promising strategy for designing efficient Cu-based catalysts with exceptional C2+ products.

Extracellular vesicles derived from mesenchymal stem cells mediate extracellular matrix remodeling in osteoarthritis through the transport of microRNA-29a.

BACKGROUND: Knee osteoarthritis (KOA) is a common orthopedic condition with an uncertain etiology, possibly involving genetics and biomechanics. Factors like changes in chondrocyte microenvironment, oxidative stress, inflammation, and immune responses affect KOA development. Early-stage treatment options primarily target symptom relief. Mesenchymal stem cells (MSCs) show promise for treatment, despite challenges. Recent research highlights microRNAs (miRNAs) within MSC-released extracellular vesicles that can potentially promote cartilage regeneration and hinder KOA progression. This suggests exosomes (Exos) as a promising avenue for future treatment. While these findings emphasize the need for effective KOA progression management, further safety and efficacy validation for Exos is essential. AIM: To explore miR-29a's role in KOA, we'll create miR-29a-loaded vesicles, testing for early treatment in rat models. METHODS: Extraction of bone marrow MSC-derived extracellular vesicles, preparation of engineered vesicles loaded with miR-29a using ultrasonication, and identification using quantitative reverse transcription polymerase chain reaction; after establishing a rat model of KOA, rats were randomly divided into three groups: Blank control group injected with saline, normal extracellular vesicle group injected with normal extracellular vesicle suspension, and engineered extracellular vesicle group injected with engineered extracellular vesicle suspension. The three groups were subjected to general behavioral observation analysis, imaging evaluation, gross histological observation evaluation, histological detection, and immunohistochemical detection to compare and evaluate the progress of various forms of arthritis. RESULTS: General behavioral observation results showed that the extracellular vesicle group and engineered extracellular vesicle group had better performance in all four indicators of pain, gait, joint mobility, and swelling compared to the blank control group. Additionally, the engineered extracellular vesicle group had better pain relief at 4 wk and better knee joint mobility at 8 wk compared to the normal extracellular vesicle group. Imaging examination results showed that the blank control group had the fastest progression of arthritis, the normal extracellular vesicle group had a relatively slower progression, and the engineered extracellular vesicle group had the slowest progression. Gross histological observation results showed that the blank control group had the most obvious signs of arthritis, the normal extracellular vesicle group showed signs of arthritis, and the engineered extracellular vesicle group showed no significant signs of arthritis. Using the Pelletier gross score evaluation, the engineered extracellular vesicle group had the slowest progression of arthritis. Results from two types of staining showed that the articular cartilage of rats in the normal extracellular vesicle and engineered extracellular vesicle groups was significantly better than that of the blank control group, and the engineered extracellular vesicle group had the best cartilage cell and joint surface condition. Immunohistochemical detection of type II collagen and proteoglycan showed that the extracellular matrix of cartilage cells in the normal extracellular vesicle and engineered extracellular vesicle groups was better than that of the blank control group. Compared to the normal extracellular vesicle group, the engineered extracellular vesicle group had a better regulatory effect on the extracellular matrix of cartilage cells. CONCLUSION: Engineered Exos loaded with miR-29a can exert anti-inflammatory effects and maintain extracellular matrix stability, thereby protecting articular cartilage, and slowing the progression of KOA.

Ferritinophagy: A new idea for liver diseases regulated by ferroptosis.

BACKGROUND: The discovery of regulatory cell death has led to a breakthrough in the therapeutic field. Various forms of cell death, such as necrosis, apoptosis, pyroptosis, autophagy, and ferroptosis, play an important role in the development of liver diseases. In general, more than one form of cell death pathways is responsible for the disease state. Therefore, it is particularly important to study the regulation and interaction of various cell death forms in liver diseases. DATA SOURCES: We performed a PubMed search up to November 2022 with the following keywords: ferritinophagy, ferroptosis, and liver disease. We also used terms such as signal path, inducer, and inhibitor to supplement the query results. RESULTS: This review summarized the basic characteristics of ferritinophagy and ferroptosis and the regulation of ferroptosis by ferritinophagy and reviewed the key targets and treatment strategies of ferroptosis in different liver diseases. CONCLUSIONS: Ferritinophagy is a potential therapeutic target in ferroptosis-related liver diseases.

Steering CO2 Electroreduction Selectivity U-Turn to Ethylene by Cu-Si Bonded Interface.

Copper (Cu), with the advantage of producing a deep reduction product, is a unique catalyst for the electrochemical reduction of CO2 (CO2RR). Designing a Cu-based catalyst to trigger CO2RR to a multicarbon product and understanding the accurate structure-activity relationship for elucidating reaction mechanisms still remain a challenge. Herein, we demonstrate a rational design of a core-shell structured silica-copper catalyst (p-Cu@m-SiO2) through Cu-Si direct bonding for efficient and selective CO2RR. The Cu-Si interface fulfills the inversion in CO2RR product selectivity. The product ratio of C2H4/CH4 changes from 0.6 to 14.4 after silica modification, and the current density reaches a high of up to 450 mA cm-2. The kinetic isotopic effect, in situ attenuated total reflection Fourier-transform infrared spectra, and density functional theory were applied to elucidate the reaction mechanism. The SiO2 shell stabilizes the *H intermediate by forming Si-O-H and inhibits the hydrogen evolution reaction effectively. Moreover, the direct-bonded Cu-Si interface makes bare Cu sites with larger charge density. Such bare Cu sites and Si-O-H sites stabilized the *CHO and activated the *CO, promoting the coupling of *CHO and *CO intermediates to form C2H4. This work provides a promising strategy for designing Cu-based catalysts with high C2H4 catalytic activity.

Exploring Electronic Characteristics of Acceptor-Donor-Acceptor-Type Molecules by Single-Molecule Charge Transport.

The electronic characteristics of organic optoelectronic materials determine the performance of corresponding devices. Clarifying the relationship between molecular structure and electronic characteristics at the single-molecule level can help to achieve high performance for organic optoelectronic materials and devices, especially for organic photovoltaics. In this work, a typical acceptor-donor-acceptor (A-D-A)-type molecule is explored by combining theoretical and experimental studies to reveal the intrinsic electronic characteristics at the single-molecule level. Specifically, the A-D-A-type molecule with 1,1-dicyano methylene-3-indanone (INCN) acceptor units exhibits an enhanced conductance in single-molecule junctions when compared with the control donor molecule, because the acceptor units of the A-D-A-type molecule contribute additional transport channels. In addition, through opening the S∙∙∙O noncovalent conformational lock by protonation to expose the -S anchoring sites, the charge transport of the D central part is detected, proving that the conductive orbitals contributed by the INCN acceptor groups can penetrate the whole A-D-A molecule. These results provide important insights into the development of high-performance organic optoelectronic materials and devices toward practical applications.

Vibration-Assisted Charge Transport through Positively Charged Dimer Junctions.

Intermolecular charge transport plays a vital role in the fields of electronics, as well as biochemical systems. Here, we design supramolecular dimer junctions and investigate the effects of charge state and energy level alignment on charge transport under nanoconfinement. Incoherent tunneling caused by thermally-induced vibrations is enhanced in positively charged systems. The transition between coherent and incoherent tunneling is associated with specific molecular vibration modes. Positively charged systems with smaller torsional barriers and vibrational frequencies result in lower transition temperatures. Multiple thermal effects have a great impact on the conductance in the off-resonant tunneling, while thermally-induced vibron-assisted tunneling contributes more to the transport in the resonant tunneling. These investigations offer a deep mechanism understanding of intermolecular charge transport and facilitate the development of practical functional molecular devices.

Associations between Mobile Internet Use and Self-Rated and Mental Health of the Chinese Population: Evidence from China Family Panel Studies 2020.

With societal and technological developments, mobile Internet has become the most popular and widespread means to use the Internet in China. Thus, exploring the relationship between mobile Internet use and the self-rated health and mental health of the Chinese population is of great importance. This study empirically examined the impact of mobile Internet use on residents' health using data from the China Family Panel Studies 2020 and conducted a heterogeneity analysis. The results revealed a significant negative association between mobile Internet use and the self-rated health of the population, but a significant positive association was found relative to their mental health. The results of this analysis passed a robustness test. The results of the heterogeneity analysis showed that mobile Internet use had a more significant association with the health of residents with secondary school education and university education compared to those with primary school education or below and graduate education. Furthermore, this study addresses the endogeneity problem using the propensity-score matching model, which is shown to be better at eliminating sample selectivity bias. If endogeneity is not addressed, the negative association with mobile Internet use on residents' self-rated health will be underestimated and its positive association with their mental health will be overestimated. The Chinese government should issue guidelines on the duration of Internet use, strictly regulate exaggerated and harmful content on mobile network platforms, and strengthen people's online skills through training to improve their digital literacy, especially for rural populations.

Research progress on lncRNAs in Alzheimer's disease.

Alzheimer's disease (AD) is the common neurodegenerative disease in the center never system and the typical dementia in old people. The major pathological changes of AD are the accumulation of amyloid-ß (Aß) plaques, neurofibrillary tangles, loss of cholinergic neurons, inflammation and metabolism dysfunction. However, the molecular mechanism leading to AD pathogenesis is not clear. More and more studies reported that long non-coding RNAs (lncRNAs) play important roles in AD. In this review, we briefly introduce the recent research progress on lncRNAs in AD, including their regulation of clearance of the Aß plaques, synaptic function, inflammation reaction and mitochondrial function, and thus providing the references for that lncRNAs can serve as a potential diagnostic biomarker and therapeutic target in AD.

Chiral derivatives of covalent organic framework TpBD (NH2 )2 used as stationary phases in gas chromatography.

Chiral covalent organic framework materials have many excellent properties, which have received much attention in the field of separation. Synthesized the covalent organic framework COF-TpBD (NH2 )2 modified, respectively, by L-valine trifluoroacetyl derivative, L-hydroxyproline, and (1S)-(+)-10-camphorsulfonyl chloride, three capillary columns of chiral covalent organic framework materials were obtained for gas chromatography. Those columns are able to separate some chiral compounds, positional isomers, n-alkanes, n-alcohols, aromatic hydrocarbon mixture, and Grob's reagents. They are complementary to other chiral capillary columns and are possible for potential applications.

Simultaneous toughening and strengthening of chitin-based composites via tensile-induced orientation and hydrogen bond reconstruction.

Chitin, an abundant, biodegradable, and biocompatible polysaccharide, is one of the most ideal eco-friendly alternatives to petroleum-based plastics. However, the applications of chitin-based materials are hindered by their low processability and brittleness induced by strong hydrogen bonds. Herein, a tensile-induced orientation and hydrogen bond reconstruction strategy was developed to fabricate a chitin nanowhiskers/poly(vinyl alcohol) composite film with high strength and toughness. After stretching and hydrogen bond reconstruction, the tensile strength and elongation at break of the composite film increased from 38.6 to 115.2 MPa and 9.37% to 40.7%, respectively. Furthermore, strengthening and toughening mechanisms were also studied, which were attributed to the effects of the intra-layer orientation and interlayer sliding, respectively.

Preparation of Furfural From Xylose Catalyzed by Diimidazole Hexafluorophosphate in Microwave.

In this work, functionalized alkyl imidazolium hexafluorophosphate ILs were synthesized and characterized; then, they were applied in the conversion of xylose to furfural under the microwave method. The results showed that when CnMF was used as a catalyst, an acidic environment was provided to promote the formation of furfural. In addition, the heating method, the solvent, and the different structures of cations in the ionic liquid influenced their catalytic activity. In an aqueous solution, the yield of furfural obtained using the microwave method was better than that of the conventional heating method, and the catalytic activity of diimidazole hexafluorophosphate was better than that of monoimidazole. Meanwhile, for the diimidazole hexafluorophosphate, the change of the carbon chain length between the imidazole rings also slightly influenced the yield. Finally, the optimal yield of 49.76% was obtained at 205°C for 8 min using 3,3'-methylenebis(1-methyl-1H-imidazol-3-ium), C1MF, as a catalyst. Mechanistic studies suggested that the catalytic activity of C1MF was mainly due to the combined effect of POFn (OH)3-n and imidazole ring. Without a doubt, the catalytic activity of C1MF was still available after five cycles, which not only showed its excellent catalytic activity in catalyzing the xylose to prepare the biomass platform compound furfural but also could promote the application of functionalized ionic liquids.

[Improvement of natural product production in Streptomyces by manipulating pathway-specific regulators].

Streptomyces are major sources of bioactive natural products. Genome sequencing reveals that Streptomyces have great biosynthetic potential, with an average of 20-40 biosynthetic gene clusters each strain. However, most natural products from Streptomyces are produced in low yields under regular laboratory cultivation conditions, which hamper their further study and drug development. The production of natural products in Streptomyces is controlled by the intricate regulation mechanisms. Manipulation of the regulatory systems that govern secondary metabolite production will strongly facilitate the discovery and development of natural products of Streptomyces origin. In this review, we summarize progresses in pathway-specific regulators from Streptomyces in the last five years and highlight their role in improving the yields of corresponding natural products.

[Effect of nuciferine on gut microbiota and inflammatory response in obese model mice].

The aim of this study was to elucidate the mechanism of nuciferine on alleviating obesity based on modulating gut microbiota, ameliorating chronic inflammation, and improving gut permeability. In this study, the obese model mice were induced by high-fat diet and then randomly divided into model group, and nuciferine group; some other mice of the same week age were fed with normal diet as normal group. In the modeling process, the mice were administered intragastrically(ig) for 12 weeks. In the course of both modeling and treatment, the body weight and food intake of mice in each group were measured weekly. After modeling and treatment, the Lee's index, weight percentage of inguinal subcutaneous fat, and the level of blood lipid in each group were measured. The pathological changes of adipocytes were observed by HE staining to evaluate the efficacy of nuciferine treatment in obese model mice. 16 S rRNA sequencing analysis was conducted to study the changes in diversity and abundance of gut microbiota after nuciferine treatment. Enzyme-linked immunosorbent assay(ELISA) and quantitative Real-time polymerase chain reaction(qPCR) were used to detect the levels of inflammatory factors interleukin-6(IL-6), interleukin-1ß(IL-1ß), tumor necrosis factor-α(TNF-α) and the expression of related genes in adipose tissue of mice in each group, so as to evaluate the effect of nuciferine on chronic inflammation of mice in obese model group. qPCR was used to detect the expression of occludin and tight junction protein 1(ZO-1)gene in colon tissure, so as to evaluate the effect of nuciferine on intestinal permeability of mice in obese group. Nuciferine decreased the body weight of obese mice, Lee's index, weight percentage of inguinal subcutaneous fat(P<0.05), and reduced the volume of adipocytes, decreased the level of total cholesterol(TC), triglyceride(TG), and low density lipoprotein cholesterol(LDL-C)(P<0.05) in serum, improved dysbacteriosis, increased the relative abundance of Alloprevotella, Turicibacter, and Lactobacillus, lowered the relative abundance of Helicobac-ter, decreased the expression of inflammatory cytokines IL-6, IL-1ß, and TNF-α genes in adipose tissue(P<0.01), decreased the levels of inflammatory cytokines IL-6, IL-1ß, and TNF-α in serum(P<0.05), and increased the expression of occludin and ZO-1 genes related to tight junction in colon tissue(P<0.01). Nuciferine could treat obesity through modulating gut microbiota, decreasing gut permeability and ameliorating inflammation.

miR-135a-5p mediates memory and synaptic impairments via the Rock2/Adducin1 signaling pathway in a mouse model of Alzheimer's disease.

Aberrant regulation of microRNAs (miRNAs) has been implicated in the pathogenesis of Alzheimer's disease (AD), but most abnormally expressed miRNAs found in AD are not regulated by synaptic activity. Here we report that dysfunction of miR-135a-5p/Rock2/Add1 results in memory/synaptic disorder in a mouse model of AD. miR-135a-5p levels are significantly reduced in excitatory hippocampal neurons of AD model mice. This decrease is tau dependent and mediated by Foxd3. Inhibition of miR-135a-5p leads to synaptic disorder and memory impairments. Furthermore, excess Rock2 levels caused by loss of miR-135a-5p plays an important role in the synaptic disorder of AD via phosphorylation of Ser726 on adducin 1 (Add1). Blocking the phosphorylation of Ser726 on Add1 with a membrane-permeable peptide effectively rescues the memory impairments in AD mice. Taken together, these findings demonstrate that synaptic-related miR-135a-5p mediates synaptic/memory deficits in AD via the Rock2/Add1 signaling pathway, illuminating a potential therapeutic strategy for AD.

[Anti-inflammatory effect, plasma effective components and therapeutic targets of Huanglian Jiedu Decoction on ulcerative colitis mice].

This paper was to investigate the effect of Huanglian Jiedu Decoction(HLJD) on ulcerative colitis(UC) in mice, and determine the effective components in plasma, and virtually screen its therapeutic target, and predict its mechanism. Sixty Balb/c mice were randomly divided into blank group, model group, mesalazine treatment group(0.3 g·kg~(-1)), and HLJD treatment groups(24.66, 12.33, 6.17 g·kg~(-1)). Excepted for the blank group, all the mice in HLJD and mesalazine treatment groups were gavage administration. All mice freely drank 2.5% DSS solution for seven days to induce UC. The disease activity index(DAI) was detected each day. At the end of the experiment, HE staining was used to observe the pathological changes in colon. The content of IL-1ß, IL-6 and TNF-α in colon were determined by ELISA. The effective components in plasma were determined by UPLC-Q-TOF-MS. The reverse docking in PharmMapper was used to screen the component targets. The disease targets of UC were collected by searching TTD, OMIM and GeneCards databases. The intersection of the component targets and disease targets was selected as the therapeutic targets. Then the therapeutic targets were imported into the STRING for GO and KEGG enrichment analysis. Discovery Studio was used to simulate the docking between the components and the targets. RESULTS:: showed that the DAI in the model group increased significantly(P<0.05), and the number of inflammatory cells and infiltration degree increased significantly compared with the blank group. The DAI in HLJD treatment group was significantly reduced(P<0.05), and the number and infiltration degree of inflammatory cells were reduced compared with the model group. The ELISA results showed that the levels of IL-1ß, IL-6 and TNF-α were increased significantly in the model group(P<0.01) compared with the blank group, and significantly down regulated in the HLJD treatment group(P<0.05) compared with the model group. After UPLC-Q-TOF-MS analyse, ten components were identified. The network pharmacology analysis showed that the action targets were significantly enriched in 129 of biological processes, such as response to organic substance, chemical and oxygen-containing compound, etc., as well as 16 of signal pathways, such as IL-17, TNF and hepatitis B signal pathways, were enriched too. The results of molecular docking showed that limonin, palmatine and berberine could bind to CASP3 and MMP9 by hydrogen bond. In conclusion, HLJD could alleviate the colonic mucosal inflammatory infiltration and mucosal damage in UC mice. The mechanism may be related to the anti-inflammatory effect on UC mice by reducing the levels of IL-1ß, IL-6 and TNF-α in colon through limonin, palmatine and berberine regulating IL-17 signal pathway and TNF signal pathway via CASP3 and MMP9 meditated.

The thermodynamics and electronic structure analysis of P-doped spinel Co3O4.

The thermodynamics of phosphorus (P) doping to spinel Co3O4, for both bulk cases and (100) and (110) surface cases, is studied using first principles calculations. The doping energies of the P atom at different doping sites are carefully calculated and compared. It is shown that P doping at Co sites, at either tetrahedral or octahedral sites, is energetically favorable, while P doping and replacing O atoms are energetically unfavorable. The doping energy difference is large enough to conclude that P doping has a very strong preference to take the Co sites, rather than the O sites in spinel Co3O4. Even when O-vacancy is available, P doping and taking the O-vacancy site is thermodynamically unfavorable. The physical/chemical mechanism behind this phenomenon is carefully analyzed. Electronic structure analysis shows that P doping and replacing the Co atom brings excess electrons to the Co3O4 system, which is beneficial to enhance the electrochemical and catalytic performance of the spinel Co3O4. Our results clarified the misleading results of P doping and replacing O atoms in spinel Co3O4 reported in the literature.