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The microstructure of primary Mg 2 Si and the interface of Mg 2 Si / α -Mg modified by Sn and Sb elements in an as-cast Mg-5Sn-2Si-1.5Al-1Zn-0.8Sb (wt.%) alloy were investigated. In the primary Mg 2 Si phase not only the Si atoms but also the Mg atoms could be substituted by Sn and Sb atoms, resulting in the slightly reduced lattice constant a of 0.627 nm. An OR of Mg 2 Si phase and α -Mg in the form of [ 001 ] Mg 2 Si ∥ [ 01 1 ¯ 1 ] α , ( 220 ) Mg 2 Si ∥ ( 0 1 ¯ 12 ) α was discovered. Between primary Mg 2 Si phase and α -Mg matrix two transitional nano-particle layers were formed. In the rim region of primary Mg 2 Si particle, Mg 2 Sn precipitates sizing from 5 nm to 50 nm were observed. Adjacent to the boundary of primary Mg 2 Si particle, luxuriant columnar crystals of primary Mg 2 Sn phase with width of about 25 nm and length of about 100 nm were distributed on the α -Mg matrix. The lattice constant of the Mg 2 Sn precipitate in primary Mg 2 Si particle was about 0.756 nm. Three ORs between Mg 2 Sn and Mg 2 Si were found, in which the Mg 2 Sn precipitates had strong bonding interfaces with Mg 2 Si phase. Three new minor ORs between Mg 2 Sn phase and α -Mg were found. The lattice constant of primary Mg 2 Sn phase was enlarged to 0.813 nm owing to the solution of Sn and Sb atoms. Primary Mg 2 Sn had edge-to-edge interfaces with α -Mg. Therefore, the primary Mg 2 Si particle and α -Mg were united and the interfacial adhesion was improved by the two nano-particles layers of Mg 2 Sn phase.

In aromatic systems with large π-conjugated structures, armchair and zigzag configurations can affect each material’s electronic properties, determining their performance and generating certain quantum effects. Here, we explore the intrinsic effect of armchair and zigzag pathways on charge transport through single hexabenzocoronene molecules. Theoretical calculations and systematic experimental results from static carbon-based single-molecule junctions and dynamic scanning tunneling microscope break junctions show that charge carriers are preferentially transported along the hexabenzocoronene armchair pathway, and thus, the corresponding current through this pathway is approximately one order of magnitude higher than that through the zigzag pathway. In addition, the molecule with the zigzag pathway has a smaller energy gap. In combination with its lower off-state conductance, it shows a better field-effect performance because of its higher on-off ratio in electrical measurements. This study on charge transport pathways offers a useful perspective for understanding the electronic properties of π-conjugated systems and realizing high-performance molecular nanocircuits toward practical applications.

To alleviate the wastage of resources and environmental pollution caused by waste luminous polyester fibers, glycolysis was found rapidly to degrade luminescent polyester fibers and assist in recovering luminescent materials from the fibers. However, the luminescent performance of recycled luminescent materials is poor. To improve the performance of recovered luminescent materials, this study employs the recovery rate of luminescent materials, initial brightness, and recovery rate of Bis (2-hydroxyethyl) terephthalate as performance indexes. The present study aims at optimizing the alcoholysis process by influencing factors such as the amount of catalyst, amount of ethylene glycol added, and reaction temperature to improve the luminous performance, and explores the mechanism of alcoholysis reaction in the recovery process of luminescent materials. The results showed that, when the catalyst content is 0.1 g, the mass ratio of polyethylene terephthalate:ethylene glycol is 1:10, the reaction temperature is 170°C for 4 hours, the Bis (2-hydroxyethyl) terephthalate conversion rate reaches 61.92%, the recovery rate of luminescent materials reaches 92.53%, and the initial brightness is as high as 5.607 cd/m2.

The inherent dipole moment and higher polarizability of azulene lead to ambipolar characteristics and good gate controllability of azulene-based single-molecule transistors.

A mechano-sliding strategy for controllable assembly of nanowires was demonstrated by directly transferring chemical vapor deposition grown silicon nanowires to obtain nanoscale electronic devices.

A single-molecule field-effect transistor (FET) is the key building block of future electronic circuits. At the same time, a single-molecule FET is also a unique platform for studying physical mechanisms at the single-molecule level. How to construct single-molecule FETs and how to efficiently control the charge transfer characteristics of the devices are two core issues in the development of single-molecule FETs. In this review, we introduce the research progresses of single-molecule FETs with solid or liquid gates. Strategies to design single-molecule FETs are emphasized, including the design of functional molecules, the construction of gate electrodes and the control of molecule-electrode interface coupling. These single-molecule FETs provide a basis for practical applications and the exploration of physical laws. Specifically, the physical mechanisms of single-molecule FETs, especially those related to interfacial coupling, are explained, such as energy level shift, Coulomb blockade effect, Kondo effect and electron-phonon coupling. The applications of single-molecule FETs are summarized, including the regulation of quantum interference, spin, thermoelectric effect and superconductivity. Finally, the current opportunities and challenges in the field of single-molecule FETs are proposed, aiming to promote the future development of single-molecule electronics.

The degradation process of RNA is decisive in guaranteeing high-fidelity translation of genetic information in living organisms. However, visualizing the single-base degradation process in real time and deciphering the degradation mechanism at the single-enzyme level remain formidable challenges. Here, we present a reliable in-situ single-PNPase-molecule dynamic electrical detector based on silicon nanowire field-effect transistors with ultra-high temporal resolution. These devices are capable of realizing real-time and label-free monitoring of RNA analog degradation with single-base resolution, including RNA analog binding, single-nucleotide hydrolysis, and single-base movement. We discover a binding event of the enzyme (near the active site) with the nucleoside, offering a further understanding of the RNA degradation mechanism. Relying on systematic analyses of independent reads, approximately 80% accuracy in RNA nucleoside sequencing is achieved in a single testing process. This proof-of-concept sets up a Complementary Metal Oxide Semiconductor (CMOS)-compatible playground for the development of high-throughput detection technologies toward mechanistic exploration and single-molecule sequencing.

The study was conducted to investigate the effects of dietary nonfibrous carbohydrate (NFC)/neutral detergent fiber (NDF) ratio on methanogenic archaea and cellulose-degrading bacteria in Karakul sheep by 16S rRNA gene sequencing. Twelve Karakul sheep were randomly divided into four groups, each group with three replicates, and they were fed with four dietary NFC/NDF ratios at 0.54, 0.96, 1.37, and 1.90 as groups 1, 2, 3, and 4, respectively. The experiment lasted for four periods: I (1 to 18 days), II (19 to 36 days), III (37 to 54 days), and IV (55 to 72 days); during each period, rumen contents were collected before morning feeding to investigate on methanogenic archaea and cellulose-degrading bacteria. The results showed that with an increase in dietary NFC/NDF ratio, the number of rumen archaea operational taxonomic units and the diversity of archaea decrease. The most dominant methanogens did not change with dietary NFC/NDF ratio and prolongation of experimental periods.

The hydrogenation of CO2 or CO to single organic product has received widespread attentions. Here we show a highly efficient and selective catalyst, Mo3S4@ions-ZSM-5, with molybdenum sulfide clusters ([Mo3S4]n+) confined in zeolitic cages of ZSM-5 molecular sieve for the reactions. Using continuous fixed bed reactor, for CO2 hydrogenation to methanol, the catalyst Mo3S4@NaZSM-5 shows methanol selectivity larger than 98% at 10.2% of carbon dioxide conversion at 180 °C and maintains the catalytic performance without any degeneration during continuous reaction of 1000 h. For CO hydrogenation, the catalyst Mo3S4@HZSM-5 exhibits a selectivity to C2 and C3 hydrocarbons stably larger than 98% in organics at 260 °C. The structure of the catalysts and the mechanism of COx hydrogenation over the catalysts are fully characterized experimentally and theorectically. Based on the results, we envision that the Mo3S4@ions-ZSM-5 catalysts display the importance of active clusters surrounded by permeable materials as mesocatalysts for discovery of new reactions.

The electrical detecion data and analyized data have been included in this file.

The choice of axial ligands is of great importance for the construction of high-performance Dy-based single-molecule magnets (SMMs). Here, combining axial ligands Ph

With aging, iron will accumulate in the brain, catalyzing oxidative radicals that damage brain neurons and induceAlzheimer's disease. In this experiment, we observed that in the brains of senile mice, the iron-exporting protein ferriportin was decreased. Further investigation indicated that H3K27 of the slc40a1 gene was methylated and that the methyltransferase Ezh2 was activated. To discharge the excessive iron in the brains of senile mice, we developed the YP peptide, and with it, we demethylated H3K27me of Slc40a1 by phosphorylation, activating the demethylase Kdm6a and inhibiting methyltransferase Ezh2. Consequently, the transcription of Slc40a1 was enhanced,and ferriportin was resumed. Thesenile brain reacquired the function of iron excretion, and as a result, the radicals in the brain weredecreased,and neuron damage was reduced, which finally restored the intelligence of dementia senile mice. Thus, YP could be a potential drug in the prevention of Alzheimer's disease

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.

Conventional analytic techniques that measure ensemble averages and static disorder provide essential knowledge of the reaction mechanisms of organic and organometallic reactions. However, single-molecule junctions enable the in situ, label-free and non-destructive sensing of molecular reaction processes at the single-event level with an excellent temporal resolution. Here we deciphered the mechanism of Pd-catalysed Suzuki-Miyaura coupling by means of a high-resolution single-molecule platform. Through molecular engineering, we covalently integrated a single molecule Pd catalyst into nanogapped graphene point electrodes. We detected sequential electrical signals that originated from oxidative addition/ligand exchange, pretransmetallation, transmetallation and reductive elimination in a periodic pattern. Our analysis shows that the transmetallation is the rate-determining step of the catalytic cycle and clarifies the controversial transmetallation mechanism. Furthermore, we determined the kinetic and thermodynamic constants of each elementary step and the overall catalytic timescale of this Suzuki-Miyaura coupling. Our work establishes the single-molecule platform as a detection technology for catalytic organochemistry that can monitor transition-metal-catalysed reactions in real time.

The completely selective oxidation of toluene to benzaldehyde with dioxygen, without the need to use H2O2, halogens, or any radical initiators, is a reaction long desired but never previously successful. Here, we demonstrate the enzyme-like mechanism of the reaction over hexadecylphosphate acid (HDPA)-bonded nano-oxides, which appear to interact with toluene through specific recognition. The active sites of the catalyst are related to the ability of HDPA to change its bonding to the oxides between monodentate and bidentate during the reaction cycle. This greatly enhances the mobility of the crystal oxygen or the reactivity of the catalyst, specifically in toluene transformations. The catalytic cycle of the catalyst is similar to that of methane monooxygenase. In the presence of catalyst and through O2 oxidation, the conversion of toluene to benzaldehyde is initiated at 70 dC. We envision that this novel mechanism reveals alternatives for an attractive route to design high-performance catalysts with bioinspired structures.

Summary Conventional mechanistic studies based on detection of species concentration reveal the basic laws of matter conversion, but inherently display ensemble averages. Single-molecule detection provides a solution and direct visualization of reaction pathway rather than only detection of species. Here, we establish an in situ label-free electrical detection platform and report universal single-molecule electrical spectroscopy (SMES) of organocatalysis to decipher the intrinsic mechanism of a benzoin reaction. This SMES is capable of monitoring each event in a simple (homo-condensation) or complex (cross-condensation) system. Both experimental and theoretical results consistently revealed accuracy of the spectroscopic attribution and proved its reliability. Furthermore, the correlation of adjacent events in the spectroscopy indicated the local repeated interaction between a catalyst and a substrate. Through a new thermodynamic and kinetic model, the inventory of substrates around the single-molecule catalyst can be reversely deduced, which enables quantitative analysis of the target single molecule.

Development of high-performance and cost-effective catalysts for electrocatalytic hydrogen evolution reaction (HER) play crucial role in the growing hydrogen economy. Recently, the atomically dispersed metal catalysts have attracted increasing attention due to their ultimate atom utilization and great potential for highly cost-effective and high-efficiency HER electrocatalyst. Herein, we propose a high-temperature treatment strategy to furtherly improve the HER performance of atomically dispersed Pt-based catalyst. Interestingly, after appropriate high-temperature treatment on the atomically dispersed Pt0.8@CN, the Pt species on the designed N-doped porous carbon substrate with rich defect sites can be re-dispersed to single atom state with new coordination environment. The obtained Pt0.8@CN-1000 shows superior HER performance with overpotential of 13 mV at 10 mA cm−2 and mass activity of 11,284 mA/mgPt at −0.1 V, much higher than that of the pristine Pt0.8@CN and commercial Pt/C catalyst. The experimental and theoretical investigations indicate that the high-temperature treatment induces the restructuring of coordination environment and then the optimized Pt electronic state leads to the enhanced HER performances. This work affords new strategy and insights to develop the atomically dispersed high-efficiency catalysts.

The essential role of drunkenness on the healthy development of Chinese Baijiu was studied in this research. This study revealed the effects of Baijiu on the behaviors of mice and evaluated the degree of drunkenness of soy sauce-, strong-, light-, and light and soy sauce-flavored Baijiu. The parameters obtained from the open field test were transformed into the behavioral drunkenness index by mathematical statistical analysis and the drunkenness-associated key compounds of Baijiu were analyzed. The results showed that strong- and light-flavored Baijiu presented higher levels of drunkenness and sobriety than soy sauce-flavored Baijiu. Interestingly, light and soy sauce-flavored Baijiu showed low drunkenness but a high sobriety degree. Specifically, the degree of drunkenness was positively correlated with fusel alcohol and aldehydes but negatively correlated with esters and acids. This study will enrich references for Baijiu behavior studies and lay a foundation for the research and development of healthy Baijiu.

Background Anastomotic leakage remains one of the most common serious complications after rectal cancer surgery. How to predict its occurrence and prevent it remains largely elusive. Objective This study aimed to identify the risk factors of anastomotic leakage and construct a nomogram for predicting postoperative anastomotic leakage in patients with rectal cancer. Methods The data of 406 patients with rectal cancer after gastrointestinal surgery in the Third Affiliated Hospital of Sun Yat-sen University from January 2011 to May 2020 were collected (243 in the training set and 163 in the testing set). Logistic regression was applied to determine the risk factors of postoperative anastomotic leakage of rectal cancer, and a nomogram prediction model was thus established. Predictive performance of the nomogram was evaluated by C-index and area under the receiver-operating characteristic (ROC) curve. Results Logistic regression analysis showed that preoperative bowel obstruction (odds ratio [OR] = 12.846, 95% confidence interval CI [1.441–114.54], p = 0.022) and early first defecation after surgery (OR = 0.501, 95% CI [0.31–0.812], p = 0.005) were independent risk factors, which could be used to develop a nomogram to predict the occurrence of anastomotic leakage accurately. The evaluation of the prediction model shows that the C-index value of the model was 0.955, the area under the ROC curve (AUC) of the training set was 0.820, and the testing set was 0.747, whereas the optimal cut-off point based on the nomogram score was 174.6. Conclusion This nomogram had a good prediction ability for postoperative anastomotic leakage in patients with rectal cancer. It can provide a reference for perioperative treatment and the selection of surgical methods to promote individualized and accurate treatment.

Background Previous study has shown that chemokine-like factor (CKLF)-like MARVEL transmembrane domain-containing family member 4 (CMTM4) can bind and maintain programmed cell death ligand 1 (PD-L1) expression to promote tumor progression by alleviating the suppression of tumor-specific T cell activity, suggesting its potential role in tumor immunotherapy. However, the role of CMTM4 in tumor immunity has not been well clarified, especially in hepatocellular carcinoma (HCC). Methods The protein expression of CMTM4/PD-L1/CD4/CD8 was detected by immunohistochemistry (IHC) detection in 90 cases of HCC tissues. The mRNA expression profiles and related prognosis data were obtained from The Cancer Genome Atlas-Liver Hepatocellular Carcinoma (TCGA-LIHC). Two immune therapy cohorts were from Imvigor210 and GSE176307. Results Though the single protein expression of CMTM4, PD-L1, CD4 or CD8 in HCC tissues by IHC detection didn’t show a significant relationship with the prognosis of HCC patients, we found that high co-expression of CMTM4/PD-L1/CD4 showed a good prognosis of HCC patients. Further Timer 2.0 analysis identified that HCC patients with high expression of CMTM4/PD-L1 and high infiltration of CD4+ T cells had a better overall survival than those with low infiltration of CD4+ T cells. Moreover, a series of bioinformatics analyses revealed that CMTM4-related genes posed important effects on prognosis and immunity in HCC patients, and CMTM4 had a positive correlation with infiltration of CD4+ and CD8+ T cells in HCC. At last, we used two immunotherapy cohorts to verify that the combination of CMTM4 with PD-L1 could improve the prognosis of tumor patients underwent immunotherapy. Conclusions CMTM4 and PD-L1 co-expression with T cell infiltration shows prognostic significance in HCC, suggesting combined effect from multiple proteins should be considered in HCC treatment.

Stacking interactions are of significant importance in the fields of chemistry, biology, and material optoelectronics because they determine the efficiency of charge transfer between molecules and their quantum states. Previous studies have proven that when two monomers are π-stacked in series to form a dimer, the electrical conductance of the dimer is significantly lower than that of the monomer. Here, we present a strong opposite case that when two anthanthrene monomers are π-stacked to form a dimer in a scanning tunneling microscopic break junction, the conductance increases by as much as 25 in comparison with a monomer, which originates from a room-temperature quantum interference. Remarkably, both theory and experiment consistently reveal that this effect can be reversed by changing the connectivity of external electrodes to the monomer core. These results demonstrate that synthetic control of connectivity to molecular cores can be combined with stacking interactions between their π systems to modify and optimize charge transfer between molecules, opening up a wide variety of potential applications ranging from organic optoelectronics and photovoltaics to nanoelectronics and single-molecule electronics.

Precise tuning of chemical reactions with predictable and controllable manners, an ultimate goal chemists desire to achieve, is valuable in the scientific community. This tunability is necessary to understand and regulate chemical transformations at both macroscopic and single-molecule levels to meet demands in potential application scenarios. Herein, we realise accurate tuning of a single-molecule Mizoroki-Heck reaction via applying gate voltages as well as complete deciphering of its detailed intrinsic mechanism by employing an in-situ electrical single-molecule detection, which possesses the capability of single-event tracking. The Mizoroki-Heck reaction can be regulated in different dimensions with a constant catalyst molecule, including the molecular orbital gating of Pd(0) catalyst, the on/off switching of the Mizoroki-Heck reaction, the promotion of its turnover frequency, and the regulation of each elementary reaction within the Mizoroki-Heck catalytic cycle. These results extend the tuning scope of chemical reactions from the macroscopic view to the single-molecule approach, inspiring new insights into designing different strategies or devices to unveil reaction mechanisms and discover novel phenomena.

In recent years, natural polymer-based electrospun fibers (EFs) with huge specific surface area, good biocompatibility, and biological activity obtained from electrospinning process exhibit tremendous vitality in the field of biomedical areas. Herein, the parameters of electrospinning from two perspectives, polymer solution such as solvent, polymeric relative molecular mass, concentration, viscosity, and conductivity of the solution, and electrospinning process such as spinning voltage, spinning flow rate, needle tip to collector distance, temperature, and humidity are first detailed. Next, the raw materials consisting of polysaccharides such as cellulose, hyaluronic acid, alginate, and chitosan as well as proteins such as collagen, gelatin, silk fibroin, and keratin are summarized. The preparation method and related characteristics of EFs with multistage structures such as porous, core-shell, Janus, bamboo-like and other structures are introduced. The biomedical applications of these natural polymer-based EFs mainly including tissue engineering, drug sustained release, wound dressings, and biomedical sensors are systematically recapitulated. Finally, the outlook on natural EFs is further proposed.