Analysis of the Rolling Interface Contact Characteristics in Mixed Lubrication Based on Gaussian Distribution Theory.

To reveal the influence of surface morphology characteristics in mixed lubrication on the contact characteristics of the rolling interface, a random three-dimensional rough surface model based on Gaussian distribution theory was established. The model utilizes the finite element method (FEM) to simulate the regular contact and tangential sliding behavior of micro-asperities at the rolling interface in mixed lubrication conditions. The connection bearing capacity of models with varied roughness in mixed lubrication was studied. Furthermore, the effect of various sliding and normal indentation amounts on the normal and friction stress was investigated. The simulation result reveals that the roughness of the surface influences the distribution of the lubricating oil film. The lubricating oil layer between the interfaces with a lower roughness has a higher bearing capacity due to its more uniform distribution of peaks and valleys. An increase in the normal indentation amount raises the friction stress and normal stress. In contrast, an increase in sliding lowers the normal pressure, substantially impacting the fluctuation of the friction coefficient dramatically. Finally, the random three-dimensional rough surface model is verified by comparing it with the experimental data in the related literature.

Temperature-Responsive Nanoporous Membranes from Self-Assembly of Poly(N-isopropylacrylamide) Hairy Nanoparticles.

Nanoporous membranes play a critical role in numerous separations on laboratory and industrial scales, ranging from water treatment to biotechnology. However, few strategies exist that allow for the preparation of mechanically robust nanoporous membranes whose separation properties can be easily tuned. Here, we introduce a new family of tunable nanoporous membranes based on nanoparticles decorated with temperature-responsive polymer brushes. We prepared mechanically robust membranes from hairy nanoparticles (HNPs) carrying PNIPAM polymer brushes. We assembled the HNPs into thin films through pressure-driven deposition of nanoparticle suspensions and measured the permeability and filtration cutoff of these membranes at different temperatures. The membrane pore diameter at room temperature varied between 10 and 30 nm depending on the polymer length. The water permeability of these membranes could be controlled by temperature, with the effective pore diameter increasing by a factor of 3-6 (up to 100 nm) when the temperature was increased to 60 °C. The size selectivity of these membranes in the filtration of nanoparticles could also be attenuated by temperature. Molecular dynamics computer simulations of a coarse-grained HNP model show that temperature-sensitive pores sizes are consistent with our experimental results and reveal the polymer configurations responsible for the observed filtration membrane permeability. We expect that these membranes will be useful for separations and in the preparation of responsive microfluidic devices.

A Directly Moldable, Highly Compact, and Easy-for-Integration 3D Micromixer with Extraordinary Mixing Performance.

Micromixers are a critical component in microfluidics. However, most 2D passive micromixers produce optimal mixing at a high flow rate range and 3D micromixers require mm-scale channels or a complex assembly that is unsuitable for microfluidic applications. Here, we reported a 3D PDMS micromixer based on the splitting-stretching-recombination (SSR) of streams to facilitate molecular diffusion, which can effectively and rapidly mix solutions with low Reynolds numbers (0.01-10). The fabrication of our micromixer is convenient with only two steps─two-photon polymerization (2PP) 3D printing and soft lithography, with high resolution, reproducibility, and ease for integration. We investigated the mixing performance of the micromixer by CFD simulations and experimental studies under a confocal microscope; the results confirmed its better performance and higher chip miniaturization than others. It can achieve a mixing efficiency above 0.90 (which is generally regarded as complete mixing) for low-Re solutions (flow rates ≤60 µL/min) with a mixing volume smaller than 20 nL. The time for complete mixing is in the range of milliseconds (e.g., 21 ms for Re = 10, 194 ms for Re = 0.88). The device shows negligible degradation in mixing performance for highly viscous solutions (∼50 times more viscous than water), macromolecule solutions, and colloidal solutions of nanoparticles.

BART-D2 subtype of EBV encoded BART miRNA cluster 1 region is strongly associated with endemic nasopharyngeal carcinoma.

Epstein-Barr virus (EBV)-encoded BamHI A rightward transcript (BART) microRNAs (miRNAs) play important roles in viral infection and tumorigenesis. The association of sequence variations in the BART miRNA cluster 1 region with diseases remains unclear. Herein, 6 types and 11 subtypes of BART cluster 1 were identified in 354 tumors and healthy donors (HDs) from nasopharyngeal carcinoma (NPC)-endemic and nonendemic China (genotyped data), and 905 EBV genomes retrieved from GenBank from diseased and normal people from around the world (archived data). The distributions of BART cluster 1 types/subtypes between NPC-endemic and nonendemic China; between Asian regions and Africa/Europe & Australia & United States; and among Asian regions (NPC-endemic China, NPC-nonendemic East Asia and Southeast Asia) were significantly different (p < 0.001). The subtype BART-D2 was not found outside Asia and was only common in NPC-endemic China. More importantly, BART-D2 had a higher frequency in NPCs than in HDs in NPC-endemic China (genotyped data, 78.0% vs. 44.1%, p < 0.001; achieved data, 89.3% vs. 43.7%, p < 0.001), and was also more frequent in NPCs than in HDs, gastric carcinomas, and lymphomas in NPC-nonendemic China (genotyped data, 27.9% vs. 1.9%, 2.4%, and 0.0%, p < 0.001). BART-D2 was preferentially linked with the high-risk subtypes for NPC previously reported, 162476C or 163364T, in the BALF2 gene, and was associated with NPC risk (p < 0.01). In vitro experiments showed that BART-D2 affected the expression of some mature BART miRNAs. These findings demonstrate geographically restricted variations of BART cluster 1 and identify distinct subtype that is confined to NPC-endemic China and is associated with NPC.

LncRNA FGD5-AS1 reduces cardiomyocyte apoptosis and inflammation by modulating Akt and miR-223-3p expression.

OBJECTIVES: Long non-coding RNAs (lncRNAs) are known to be involved in heart development and function. In this study, we aimed to explore the effect of the lncRNA FGD5 antisense RNA 1 (FGD5-AS1) on acute myocardial infarction (AMI) by targeting miR-223-3p. METHODS: An AMI model was established both in vivo and in vitro. The levels of FGD5-AS1, miR-223-3p and inflammatory factors were detected by real-time quantitative reverse transcription PCR. Cardiomyocyte apoptosis was assessed using TdT-mediated dUTP nick-end labeling assay. The protein levels of cleaved caspase-3, Bcl-2 and Bax were examined using Western blot. Cardiac function was evaluated using hemodynamic analysis and hematoxylin-eosin and Masson's trichrome staining. In addition, an underlying competitive endogenous RNA mechanism was revealed by bioinformatics analysis, dual-luciferase reporter assay and rescue experiments. RESULTS: We found decreased expression of FGD5-AS1 in AMI. Furthermore, FGD5-AS1 expression significantly decreased the infarct size, improved cardiac performance and attenuated cardiac fibrosis by reducing myocardial apoptosis and inflammation. miR-223-3p was a direct target of FGD5-AS1. Moreover, miRNA-223-3p directly downregulated the expression of phosphorylated Akt in primary neonatal rat cardiomyocytes. Further experiments demonstrated that FGD5-AS1 modulated Akt activity to reduce myocardial injury through miR-223-3p. CONCLUSION: The FGD5-AS1/miR-223-3p/Akt pathway is involved in AMI, suggesting that FGD5-AS1 may act as a potential biomarker and therapeutic target for AMI.

Preparation of High Thermo-Stability and Compactness Microencapsulated Phase Change Materials with Polyurea/Polyurethane/Polyamine Three-Composition Shells through Interfacial Polymerization.

In the preparation of microencapsulated phase change materials (MicroPCMs) with a three-composition shell through interfacial polymerization, the particle size, phase change behaviors, core contents, encapsulation efficiency morphology, thermal stability and chemical structure were investigated. The compactness of the MicroPCMs was analyzed through high-temperature drying and weighing. The effect of the core/shell ratio and stirring rate of the system was studied. The results indicated that the microcapsules thus-obtained possessed a spherical shape and high thermal stability and the surfaces were intact and compact. Furthermore, in the emulsification stage, the stirring speed had a significant influence on the microcapsules' particle size, and smaller particles could be obtained under the higher stirring speed, and the distributions were more uniform in these cases. When the core/shell ratio was lower than 4, both the core content and the encapsulation efficiency was high. Additionally, when the core/shell ratio was higher than 4, the encapsulation efficiency was decreased significantly. The three-composition shell greatly increased the compactness of microcapsules, and when the core/shell ratio was adjusted to 3, the mass loss of the MicroPCMs was lower than 6% after drying at 120 °C for 1 h. After the microencapsulation, double exothermic peaks appeared on the crystallization curve of the MicroPCMs, the crystallization mechanism was changed from the heterogeneous nucleation to the homogeneous nucleation and the super cooling degree was enhanced.

Scattering of Magnetoacoustic Waves and Dynamic Stress Concentration around Double Openings in Piezomagnetic Composites.

Based on the magnetoacoustic coupled dynamics theory, the wave function expansion method is used to solve the problem of acoustic wave scattering and dynamic stress concentration around the two openings in e-type piezomagnetic composites. To deal with the multiple scattering between openings, the local coordinate method is introduced. The general analytical solution to the problem and the expression of the dynamic stress concentration are derived. As an example, the numerical results of the dynamic stress distribution around two openings with equal diameters are given. The effects of the parameters, such as the incident wave number and the spacing between the openings, on the dynamic stress concentration factor are analyzed.

In situ synthesis of silver or selenium nanoparticles on cationized cellulose fabrics for antimicrobial application.

In this study, we developed a method to prepare inorganic nanoparticles in situ on the surface of cationized cellulose using a rapid microwave-assisted synthesis. Selenium nanoparticles (SeNPs) were employed as a novel type of antimicrobial agent and, using the same method, silver nanoparticles (AgNPs) were also prepared. The results demonstrated that both SeNPs and AgNPs of about 100 nm in size were generated on the cationized cellulose fabrics. The antibacterial tests revealed that the presence of SeNPs clearly improved the antibacterial performance of cationized cellulose in a similar way as AgNPs. The functionalised fabrics demonstrated strong antibacterial activity when assessed using the challenge test method, even after repeated washing. Microscopic investigations revealed that the bacterial cells were visually damaged through contact with the functionalised fabrics. Furthermore, the functionalised fabrics showed low cytotoxicity towards human cells when tested in vitro using an indirect contact method. In conclusion, this study provides a new approach to prepare cationic cellulose fabrics functionalised with Se or Ag nanoparticles, which exhibit excellent antimicrobial performance, low cytotoxicity and good laundry durability. We have demonstrated that SeNPs can be a good alternative to AgNPs and the functionalised fabrics have great potential to serve as an anti-infective material.

Effects of miR-22-3p targeted regulation of Socs3 on the hepatic insulin resistance in mice with gestational diabetes mellitus.

OBJECTIVE: Gestational diabetes mellitus (GDM) is one of the common complications of pregnant women, with serious threatening to pregnant women and newborns. The pathogenesis of GDM remains unclear now. This study aims to explore the effects of miR-22-3p targeted regulation of suppressors of cytokine signaling 3 (Socs3) on the hepatic insulin resistance (HIR) in mice with GDM. METHODS: Healthy SPF C57BL/6J mice were selected to establish GDM model and divided into 7 groups: Normal group, Model group, NC-(negative control) mimic group, miR-22-3p mimic group, NC-pcDNA3.0 group, pcDNA3.0-Socs3 group, and miR-22-3p mimic + pcDNA3.0-Socs3 group. The islet morphology, and the expressions of miR-22-3p, Socs3 mRNA and Socs3 protein in the islet tissues were detected by HE staining, qRT-PCR and Western blot. Fasting blood glucose (FBG), triglyceride (TG), total cholesterol (TC), and high-density lipoprotein cholesterol (HDL-C) were measured. Oral glucose tolerance test (OGTT) was performed to detect FBG and fasting insulin (FINS) contents, and insulin resistance (HOMA-IR) was calculated. RESULTS: Compared with the Normal group, the model group had decreased levels of miR-22-3p and HDL-C, while increased levels of Socs3 mRNA and protein expressions, OGTT, FBG, FINS, and HOMA-IR, TG and TC (all P < 0.05). Compared with the Model group, the above indicators (OGTT, FBG, FINS, HOMA-IR, TG, TC and HDL-C) were improved in the miR-22-3p mimic group, but worsened in the pcDNA3.0-Socs3 group (all P < 0.05). CONCLUSION: miR-22-3p can down-regulate the expression of Socs3, thereby inhibiting HIR in GDM mice.

Responsive Nanoporous Membranes with Size Selectivity and Charge Rejection from Self-Assembly of Polyelectrolyte "Hairy" Nanoparticles.

We report the preparation and characterization of charged nanoporous membranes by self-assembly of "hairy" silica nanoparticles (HNPs) functionalized with polyelectrolyte copolymer brushes. We show that HNP membranes possess high water flux, have well-defined pore sizes, and rejection up to 80% of charged species in solution. The properties of these membranes can be tuned by controlling the length and composition of polymer brushes and the electrolyte concentration in solution. We demonstrate that membrane pore sizes undergo changes of up to 40% in response to changes in the ionic strength of the salt solution. Using MD computer simulations of a coarse-grained model, we link these tunable properties to the conformations of polymer chains in the spaces between randomly packed HNPs. As polymer length increases, the polymers fill the interparticle gaps, and the pore size decreases markedly. On the basis of their straightforward fabrication and tunable properties, HNP membranes may find applications in size- and charge-selective separations, water desalination, and responsive devices.

Zirconium/Nickel-Mediated One-Pot Ketone Synthesis.

A zirconium/nickel-mediated one-pot synthesis of ketones is reported. In the presence of Zn or Mn, Cp2 ZrCl2 was found to dramatically accelerate the coupling and suppress side product formation via an I→SPy displacement at the same time. Unlike Zn/Pd- and Fe/Cu-mediated one-pot ketone syntheses, the new method is effective for nucleophiles bearing OR or equivalent functional groups at the α-position. A mechanism comprising a nickel catalytic cycle, a zirconium catalytic cycle, and Zr→Ni transmetalation is proposed, and Cp2 ZrCl2 and/or low-valent Zr species are suggested to play crucial dual roles.

Regioselective Amine-Borane Cyclization: Towards the Synthesis of 1,2-BN-3-Cyclohexene by Copper-Assisted Triazole/Gold Catalysis.

The combination of triazole/gold (TA-Au) and Cu(OTf)2 is identified as the optimal catalytic system for promoting intramolecular hydroboration for the synthesis of a six-membered cyclic amine-borane. Excellent yields (up to 95 %) and regioselectivities (5-exo vs. 6-endo) were achieved through catalyst control and sequential dilution. Good functional-group tolerance was attained, thus allowing the preparation of highly functionalized cyclic amine-borane substrates, which could not be achieved using other methods. Deuterium-labeling studies support the involvement of a hydride addition to a gold-activated alkyne with subsequent C-B bond formation.

Graphene plasmons isolator based on non-reciprocal coupling.

In this paper we propose a graphene plasmons isolator based on non-reciprocal coupling within double graphene layer waveguide structure on a magneto-optical substrate. The difference in modal indices of graphene plasmons in opposite directions enables non-reciprocal coupling, which is theoretically investigated via coupled mode theory (CMT) and shows good agreement with numerical finite elements methods (FEM). The non-reciprocal coupling endows such system functionalities as magnetically controlled "plasmons circulator" or "plasmons isolator". For the latter case, systematical investigations of the insertion losses and isolation ratios with respect to the structural parameters, material properties, environmental parameters, fabrication errors as well as dielectric damping are presented. Theoretical investigation has shown an isolation ratio as 42 dB. The proposed plasmons circulator and isolator may serve as potential building blocks in graphene plasmons circuits.

Ambient synthesis of dienals via triazole-gold and amine catalysis relay.

A highly efficient synthesis of substituted conjugated dienals was developed through a triazole-gold (TA-Au)-catalyzed propargyl vinyl ether rearrangement followed by an amine catalyzed allene-aldehyde tautomerization. Various substituted vinylogous aldehydes were prepared in one pot with good to excellent yields (up to 95%) under mild conditions with high atom economy.

Synthesis of cyclic amine boranes through triazole-gold(I)-catalyzed alkyne hydroboration.

The first catalytic alkyne hydroboration of propargyl amine boranecarbonitriles is accomplished with triazole-Au(I) complexes. While the typical [L-Au](+) species decomposes within minutes upon addition of amine boranecarbonitriles, the triazole-modified gold catalysts (TA-Au) remained active, and allowed the synthesis of 1,2-BN-cyclopentenes in one step with good to excellent yields. With good substrate tolerability and mild reaction conditions (open-flask), this new method provides an alternative route to reach the interesting cyclic amine borane with high efficiency.

Gold-catalyzed intermolecular C-S bond formation: efficient synthesis of α-substituted vinyl sulfones.

A general method for the synthesis of α-substituted vinyl sulfones makes use of a combination of a triazole gold complex and gallium triflate. This efficient CS bond formation between simple terminal alkynes and sulfinic acids provides access to various α-substituted vinyl sulfones.

Quantitative kinetic investigation of triazole-gold(I) complex catalyzed [3,3]-rearrangement of propargyl ester.

The triazole-gold(I) complex catalyzed [3,3]-rearrangement of propargyl ester has been quantitatively investigated through in situ IR. First order dependence of the initial rates on [Au] and [propargyl ester] suggested that the turnover-limiting step is the associative ligand substitution. The activation enthalpy was also determined to be 7.8 kcal mol(-1). TA-Au catalysts with different triazole derivatives were also tested, giving a linear free energy relationship with a ρ value of 0.74.

1,2,3-triazoles: gas phase properties.

1,2,3-Triazoles have come to the forefront as compounds of import in a vast number of applications. The fundamental properties of these species, however, remain largely unknown. Herein, the gas phase properties of 4-phenyl-1,2,3-triazole, benzotriazole, and a series of 1-phenylbenzotriazoles are described. Proton affinity and acidity values are computed and measured. Furthermore, ion-molecule reactions and H/D exchange studies are used to ascertain tautomer prevalence for the 4-phenyl species.

Stereoselective synthesis of N-heterocycles through amine addition to nitroalkenes.

An efficient route for the preparation of substituted N-heterocycles was developed through the amine addition to nitroalkenes. The reaction tolerates a large substrate scope with good to excellent yields (up to 95%) and excellent stereoselectivities (up to 99 : 1 dr).

Ambient Schmittel cyclization promoted by chemoselective triazole-gold catalyst.

The Schmittel cyclization was achieved at room temperature through triazole-gold (TA-Au) catalyzed propargyl vinyl ether rearrangement. Other tested [L-Au](+) catalysts gave complex reaction mixtures under identical conditions with no desired products observed. Importantly, because of the employment of mild conditions, sterically hindered groups (such as t-Bu) on allene termini were no longer required, which allowed successful synthesis of previously challenging substrates.