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This theoretical study shows the mechanism of MD reaction on Pt1/CeO2(110), Pt7/CeO2(110), and Pt1/Ce1−xO2(110) surfaces and demonstrates that adjusting the loading position of Pt single atoms can effectively improve the catalytic activity.

Inductively coupled plasma-mass spectrometry (ICP-MS) is one of the most powerful techniques for multiplex nucleotide assay owing to the virtue of the high resolution of multiple-elements' mass to charge ratio, in a mass spectrum. Here, a small sized (less than 20 nm) noble-metal nanoparticle labelled ICP-MS (NP-ICP-MS) is proposed for high-throughput microRNA (miRNA) determination. Three miRNA targets - miR-486-5p, miR-221, and miR-21 - in serum, were distinguished by single-stranded DNA (ssDNA) probes labelled with a small sized noble-metal nanoparticle - silver nanoparticles (AgNPs), platinum nanoparticles (PtNPs), and gold nanoparticles (AuNPs). The counting isotopes ion intensity per second (CPS) of the noble-metal label versus internal standard isotope intensity of 115In and 209Bi, exhibited good linearity in the range 0.25 pM to 100 pM with correlation coefficients (R2) of 0.9680, 0.9305, and 0.9418. The specific sandwich-type miRNA assay using the sensitive NP-ICP-MS readout pushed the detection limits down to 0.18 pM for miR-221, 0.23 pM for miR-486-5p, and 0.22 pM for miR-21. And the relative standard deviations (RSDs) for 10 pM target miRNA were less than 3.7%. This work promises a potential ultrasensitive ICP-MS bioassay of multiplex miRNA biomarkers for clinical serum diagnosis.

Density functional theory (DFT) calculations are carried out to investigate the effect of point defects on acetylene hydrogenation reaction over Ni(111) surface with three different defect concentrations (DC = 0.0500, 0.0625, and 0.0833), compared with the perfect Ni(111) surface. The adsorptions of C2 species and H atoms and the mechanism of acetylene hydrogenation via the ethylene pathway are systematically analyzed. The results indicate that the existence of defects will make C2 species and H atoms more inclined to adsorb near the defects. Introducing an appropriate amount of point defect concentration can enhance the catalytic activity and ethylene selectivity of Ni. In this work, DC = 0.0625 Ni(111) surface has the highest catalytic activity and selectivity of ethylene. This work provides useful theoretical information on the effect of defects on acetylene hydrogenation and is helpful for the design of Ni and related metal catalysts with defects.

The ion exchange reaction has been extensively used in the field of synthesis of functionalized supramolecular materials such as layered double hydroxides (LDHs), ion-embedded batteries, sewage disposal and so on. In this work, the factors influencing the anion exchange behavior in the LDH gallery, such as the exchange domain, the exchange order, the driving force, and the diffusion of the anions, are investigated systematically using molecular dynamics (MD) simulations and density functional theory (DFT) methods in view of both thermodynamics and dynamics. 159 models of MIIRAl-A-LDHs (MII = Mg, Ni, Zn; R = 1.4-8, A = OH-, Cl-, Br-, NO3-, HCOO-, C6H5SO3-, CO32-, SO42-, and PO43-, respectively) are calculated. The results reveal that the anion exchange domain (interlayer distance) in LDHs is determined not only by the size and their arrangement modes of the guest anions, but also by the charges the anions carry. The relative binding energies of different anions and the Gibbs free energy changes of the anion exchange reactions in LDHs decrease in the order of PO43- > CO32- > SO42- > OH- > Cl- > Br- > HCOO- > NO3- > C6H5SO3-, which is in accordance with the experimental anion exchange order. The stronger the hydrogen bonding between the anion and the host, the larger the charge transfer, and the smaller the electronegativity of the anion, the more difficult it is for the anion to be exchanged out from LDH interlayer. In addition, for the anions with the same charges, the relative binding energy is linearly well correlated with the interlayer spacing. By analyzing the contribution of each energetic item comprising the total potential energy, it is found that the major driving force of anion exchange is the electrostatic force. The diffusion coefficient (D) along the c direction is nearly equal to zero, suggesting that the diffusion of anions occurs mainly in the ab plane of the LDH cell. It also can be inferred that when the cell parameter c 24.0 A, both the thermodynamic and the dynamic factors cast the same effect on the anion exchange behavior. This work provides an in-depth understanding of the anion exchange behavior, and is helpful guidance for the design and synthesis of functionalized guest anion intercalated LDHs and related materials using the anion-exchange method.

Inductively coupled plasma-mass spectrometry (ICP-MS) is one of the most powerful techniques for multiplex nucleotide assay owing to the virtue of the high resolution of multiple-elements' mass to charge ratio, in a mass spectrum. Here, a small sized (less than 20 nm) noble-metal nanoparticle labelled ICP-MS (NP-ICP-MS) is proposed for high-throughput microRNA (miRNA) determination. Three miRNA targets - miR-486-5p, miR-221, and miR-21 - in serum, were distinguished by single-stranded DNA (ssDNA) probes labelled with a small sized noble-metal nanoparticle - silver nanoparticles (AgNPs), platinum nanoparticles (PtNPs), and gold nanoparticles (AuNPs). The counting isotopes ion intensity per second (CPS) of the noble-metal label versus internal standard isotope intensity of

The ion exchange reaction has been extensively used in the field of synthesis of functionalized supramolecular materials such as layered double hydroxides (LDHs), ion-embedded batteries, sewage disposal and so on. In this work, the factors influencing the anion exchange behavior in the LDH gallery, such as the exchange domain, the exchange order, the driving force, and the diffusion of the anions, are investigated systematically using molecular dynamics (MD) simulations and density functional theory (DFT) methods in view of both thermodynamics and dynamics. 159 models of MIIRAl-A-LDHs (MII = Mg, Ni, Zn; R = 1.4-8, A = OH-, Cl-, Br-, NO3-, HCOO-, C6H5SO3-, CO32-, SO42-, and PO43-, respectively) are calculated. The results reveal that the anion exchange domain (interlayer distance) in LDHs is determined not only by the size and their arrangement modes of the guest anions, but also by the charges the anions carry. The relative binding energies of different anions and the Gibbs free energy changes of the anion exchange reactions in LDHs decrease in the order of PO43-CO32-SO42-OH-Cl-Br-HCOO-NO3-C6H5SO3-, which is in accordance with the experimental anion exchange order. The stronger the hydrogen bonding between the anion and the host, the larger the charge transfer, and the smaller the electronegativity of the anion, the more difficult it is for the anion to be exchanged out from LDH interlayer. In addition, for the anions with the same charges, the relative binding energy is linearly well correlated with the interlayer spacing. By analyzing the contribution of each energetic item comprising the total potential energy, it is found that the major driving force of anion exchange is the electrostatic force. The diffusion coefficient (D) along the c direction is nearly equal to zero, suggesting that the diffusion of anions occurs mainly in the ab plane of the LDH cell. It also can be inferred that when the cell parameter c24.0 Å, the anion exchange order is mainly determined by the thermodynamic factors, whereas when c24.0 Å, both the thermodynamic and the dynamic factors cast the same effect on the anion exchange behavior. This work provides an in-depth understanding of the anion exchange behavior, and is helpful guidance for the design and synthesis of functionalized guest anion intercalated LDHs and related materials using the anion-exchange method.

Summary Maternal nicotine exposure causes alteration of gene expression and cardiovascular programming. The discovery of nicotine-medicated regulation in cardiogenesis is of major importance for the study of cardiac defects. The present study investigated the effect of nicotine on cardiac gene expression and epigenetic regulation during myocardial differentiation. Persistent nicotine exposure selectively inhibited expression of two cardiac genes, Tbx5 and Gata4, by promoter DNA hypermethylation. The nicotine-induced suppression on cardiac differentiation was restored by general nicotinic acetylcholine receptor inhibition. Consistent results of Tbx5 and Gata4 gene suppression and cardiac function impairment with decreased left ventricular ejection fraction were obtained from in vivo studies in offspring. Our results present a direct repressive effect of nicotine on myocardial differentiation by regulating cardiac gene suppression via promoter DNA hypermethylation, contributing to the etiology of smoking-associated cardiac defects., Highlights • Nicotine downregulates Tbx5 and Gata4 during in vitro and in vivo cardiogenesis • Nicotine causes diminished cardiac differentiation and impaired cardiac function • Nicotine causes Tbx5 and Gata4 gene suppression via promoter DNA hypermethylation • nAChR antagonist restores nicotine-induced gene suppression and DNA methylation, In this article, Yu, Geng, and colleagues reveal a direct repressive effect of nicotine on myocardial differentiation by regulating suppression of two cardiac genes (Gata4 and Tbx5) via promoter DNA hypermethylation, contributing to the etiology of smoking-associated cardiac defects.

With the development of the Internet economy, live streaming sales have become a new marketing method, which is popular among users. This paper explores quality attributes of live streaming sales based on the experience of their users. In this study, 56 factors, including the original and abstract reasons for and the specific item of user experience of live streaming sales, were first obtained with the evaluation grid method according to the semi-structured interview of highly involved people. Then, 5 experts formed a focus group for discussion and determined 11 key factors influencing user experience as analysis factors of the ISM theoretical model. Results are obtained through the statistical analysis of the ISM theoretical model, and four major dimensions are defined, namely the first-level demand dimension, the second-level interaction dimension, the third-level good quality dimension and the fourth-level extension dimension. Finally, the relationship between attractive quality attributes in different dimensions and the Kano two-dimensional quality classification and user satisfaction is analyzed based on the Kano two-dimensional quality questionnaire. A satisfaction coefficient matrix diagram is drawn to analyze the key quality attributes. Research conclusions and suggestions are made according to the results of data analysis so as to provide reference value for subsequent improvement of related designs and help designers improve user experience.

This paper explores the starting point of VR (virtual reality) game experience by 5 “W” of care (What, Why, Who, Where and When), uses STEEP method to analyze the problems in different aspects of the user experience, and invites two senior people to evaluate 11 important factors. Then, the factor relationship hierarchy analysis graph is obtained with the ISM theoretical operation, and the VR game users’ problems and goals that urgently need to change are obtained. The main issue in the research is that the quality of the game story determines the experience of the users, and the side issues are the sound effect, art effect, and special effect.

By reviewing literature on short video apps and interviewing experts, this study determined three major aspects of Tik Tok user experience, emotionality, interactivity and usability, and identified nine key factors to construct the hierarchical structure of analytic hierarchy process (AHP). Based on questionnaires from experts, the Analytic Hierarchy Process (AHP) was used to determine each dimension and factor weight. Considering the defects of AHP, we introduced the fuzzy theory and fuzzy analytic hierarchy process (FAHP) to solve related problems. Finally, through the FAHP software developed by MATLAB 2015a GUI, the fuzzy weight of charm factors involved in the Tik Tok user experience is concluded as follows: emotional factors account for 48.77%, interactive factors for 31.23%, and usability factors for 20.00%. This study provides certain reference for design and update of short video apps.

Limited studies have reported the association between dietary patterns and the risk of Helicobacter pylori (H pylori) infection. The purpose of this study was to evaluate the relationship between dietary patterns and H pylori infection in a Chinese population ages from 45 to 59 years. We per

In the context of a growing pandemic of myocardial infarction (MI), the current standard therapies cannot provide an ideal outcome for the patients. Hence, novel approaches are being explored to identify curative treatment. In recent years, stem cell has been regarded as a critical source for cardiac regeneration, and several types of stem cells have been demonstrated with cardiogenic capacity. To date, thousands of patients with MI have received autologous stem cells therapy, but the benefits were modest. In this review, we summarize the recent findings of stem cells therapy in cardiac repair and regeneration, and propose the key unsolved hurdles in this field.

Alpha-amylase is a very important enzyme in the starch conversion process. Most of the α-amylases are calcium-dependent and exhibit poor performance in the simultaneous saccharification and fermentation process of industrial bioethanol production that uses starch as feedstock. In this study, an extracellular amylolytic enzyme was purified from the culture broth of newly isolated Talaromyces pinophilus strain 1-95. The purified amylolytic enzyme, with an apparent molecular weight of 58 kDa on SDS-PAGE, hydrolyzed maltopentaose, maltohexaose, and maltoheptaose into mainly maltose and maltotriose and minor amount of glucose, confirming the endo-acting mode of the enzyme, and hence, was named Talaromyces pinophilus α-amylase (TpAA). TpAA was most active at pH 4.0-5.0 (with the temperature held at 37°C) and 55°C (at pH 5.0), and stable within the pH range of 5.0-9.5 (at 4°C) and below 45°C (at pH 5.0). Interestingly, the Ca2+ did not improve its enzymatic activity, optimal temperature, or thermostability of the enzyme, indicating that the TpAA was Ca2+-independent. TpAA displayed higher enzyme activity toward malto-oligosaccharides and dextrin than other previously reported α-amylases. This highly active Ca2+-independent α-amylase may have potential applications in starch-to-ethanol conversion process.

There are lots of reasons to restrict a low-permeability oil layer to enhance the recovery factor. Based on the research results of non-Darcy flow, microflow of water drive and micro-acting force in low permeability porous media are studied by establishing the expression of fluid viscosity factor. Numerical calculation shows that under the condition of L/S interaction, the radial velocity distribution near the solid wall changes obviously, and the curve form changes from convex to concave. The tinier the capillary radius is, the stronger the L/S interaction is. The larger the n value is, more obviously the flowing velocity decreases. The results will help people to deal with improving recovery factor of low permeability reservoir, and understanding the fluid flow behavior in blood capillary.