We extend the Exp-function method to fractional partial differential equations in the sense of modified Riemann-Liouville derivative based on nonlinear fractional complex transformation. For ...illustrating the validity of this method, we apply it to the space-time fractional Fokas equation and the nonlinear fractional Sharma-Tasso-Olver (STO) equation. As a result, some new exact solutions for them are successfully established.
Since both serum uric acid (SUA) and renal artery stenosis (RAS) are associated with atherosclerotic events and renal events, it is interesting to investigate whether SUA could predict long‐term ...outcome in patients with RAS. Patients were enrolled from inpatients from 2010 to 2014, must be ≥40‐year‐old. There were 3269 hypertensive patients enrolled, including 325 RAS patients. Endpoints included all‐cause death and new or worsening nephropathy (NNP). In analysis for all‐cause mortality, associations between SUA and risk of all‐cause mortality were an arising curve in total population, a U‐shape curve in non‐RAS population, and an arising curve in RAS population. When RAS was involved in multivariate analysis, association between SUA and risk of all‐cause mortality was still an arising curve in total population. In analysis for NNP, associations between SUA and risk of NNP were a declining curve in total population, not significant in non‐RAS population, and a U‐shape curve in RAS population. When RAS was involved in multivariate analysis, association between SUA and risk of NNP in total population was no longer significant. Not only association curve of SUA with mortality in non‐RAS patients is different from association curve in RAS patients, but also association curve of SUA with NNP in non‐RAS patients is different from association curve in RAS patients. The authors conclude that mechanisms of uric acid for mortality and NNP in RAS patients are different from non‐RAS patients. In addition to renal vascular obstruction, uric acid is another significant factor for NNP and death in RAS patients.
In this paper, the (G'/G)-expansion method is extended to solve fractional partial differential equations in the sense of modified Riemann-Liouville derivative. Based on a nonlinear fractional ...complex transformation, a certain fractional partial differential equation can be turned into another ordinary differential equation of integer order. For illustrating the validity of this method, we apply it to the space-time fractional generalized Hirota-Satsuma coupled KdV equations and the time-fractional Sfth-order Sawada-Kotera equation. As a result, some new exact solutions for them are successfully established.
Abstract
Delving into the influence of strain on organic reactions in small molecules at the molecular level can unveil valuable insight into developing innovative synthetic strategies and ...structuring molecules with superior properties. Herein, we present a molecular‐strain engineering approach to facilitate the consecutive 1,2‐aryl shift (formal 1,3‐aryl shift) in molecular bows (MBs) that integrate 1,4‐dimethoxy‐2,5‐cyclohexadiene moieties. By introducing ring strain into MBs through tethering the bow limb, we can harness the intrinsic mechanical forces to drive multistep aryl shifts from the
para‐
to the
meta‐
to the
ortho‐
position. Through the use of precise intramolecular strain, the seemingly impractical 1,3‐aryl shift was realized, resulting in the formation of
ortho‐
disubstituted products. The solvent and temperature play a crucial role in the occurrence of the 1,3‐aryl shift. The free energy calculations with inclusion of solvation support a feasible mechanism, which entails multistep carbocation rearrangements, for the formal 1,3‐aryl shift. By exploring the application of molecular strain in synthetic chemistry, this research offers a promising direction for developing new tools and strategies towards precision organic synthesis.
We report here the one‐pot synthesis of benzo1,2‐a : 3,4‐a′ : 5,6‐a′′triazulene (BTA), wherein three azulene units are embedded through a tandem reaction comprising two steps, Suzuki coupling and ...Knoevenagel condensation, between a readily available triborylated truxene precursor and 8‐bromo‐1‐naphthaldehyde. Its nitration leads to a regioselective trinitrated product, namely, BTA‐NO2. Single‐crystal X‐ray crystallography revealed that the superstructure of BTA consists of a dimer stacked by two enantiomeric helicene conformers, while that of BTA‐NO2 consists of an unprecedented π‐tetramer stacked from two enantiomeric dimers, that is, four distinct helicene conformers. Both compounds show excellent stability and fluorescence with large Stokes shifts of up to 5100 cm−1. In addition, BTA‐NO2 exhibits a unique solvatochromic effect in different solvents and hydrogen‐bonding‐induced emission transfer in different ratios of THF/H2O solutions.
A C3‐symmetrical truxene‐based benzotriazulene derivative with three embedded azulene units was concisely synthesized by means of a cascade 4+3 annulation involving a Suzuki coupling followed by Knoevenagel condensation of a readily available triborylated truxene precursor and 8‐bromo‐1‐naphthaldehyde. The regioselectively trinitrated product exhibits a large Stokes shift of up to 5100 cm−1 along with unique solvatochromic effects in different solvents.
A novel 3D metamaterial with tension-torsion coupling effect is designed through connecting neighbor chiral honeycomb layers by inclined rods. Both numerical simulation and experiment analysis show ...the tension-torsion coupling effect of the metamaterial is much better compared to other metamaterials we can find in literatures. With the increase of cells number, the tension-torsion coupling effect of this metamaterial at the strain of 1% increases firstly, reaching the perk value of 11.36°, then decreases slowly, and it remains an appreciable value of 4.44° even when the cells number is 25 × 25 × 25. Analysis shows that size effect in the thickness direction can be neglected when the layers number is more than 5. The stress and deformation of struts within the metamaterial are investigated. For the inclined rods and the square loops, their main deformation is the axial deformation while the main deformation of ligaments is out-of-plane bending deformation. According to the deformation law of inclined rods, it can be concluded that when the compression strain increases, the inclined rods lying in the layer's center enter the instability state first and then instability zone expands outwards, resulting in instability state of the metamaterial.
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•A novel 3D metamaterial with outstanding tension-torsion coupling effect is designed and fabricated.•The torsion angle of metamaterial can maintain an appreciable value even when cells number is large.•The deformation modes and deformation mechanisms of the metamaterial are investigated.•The design concept provides a framework to develop tension-torsion coupling metamaterials.
Infinite Twisted Polycatenanes Liu, Jiali; Wu, Mengqi; Wu, Lin ...
Angewandte Chemie International Edition,
November 13, 2023, Letnik:
62, Številka:
46
Journal Article
Recenzirano
Polyncatenanes have exceptional mechanical bonding properties that give them tremendous potential for use in the development of molecular machines and soft materials. Synthesizing these compounds ...has, however, proven to be a formidable challenge. Herein, we describe a concise method for the construction of twisted polycatenanes. Our approach involves using preorganized double helicates as templates, linked crosswise in a linear fashion by either silver ions or triple bonds. By using this approach, we successfully synthesized twisted polycatenanes with both coordination and covalent bonding employing Ag(I) ions and ethynylene units, respectively, as the linkages and leveraging the same Ag(I)‐templated double helicate in both cases. Synthesis with Ag(I) ions formed a single‐crystalline one‐dimensional (1D) coordination polyncatenane, and synthesis using ethynylene units generated 1D fibers which self‐assembled with solvents to form a gel. Our results confirm the potential of multi‐stranded metallohelicates for creating sophisticated mechanically interlocked molecules and polymers, which could pave the way for exploration in the realms of molecular nanotopology and materials design.
A concise approach was developed to construct figure‐of‐eight polycatenanes using preorganized double helicates as templates and crosslinking them with silver ions or ethynylene units. Employing Ag(I) ions or ethynylene units as linkers resulted in single‐crystalline 1D coordination polyncatenanes and assembling gel fibers, respectively.
By training the deep neural network model, the hidden features in Surface Electromyography(sEMG) signals can be extracted. The motion intention of the human can be predicted by analysis of sEMG. ...However, the models recently proposed by researchers often have a large number of parameters. Therefore, we designed a compact Convolution Neural Network (CNN) model, which not only improves the classification accuracy but also reduces the number of parameters in the model. Our proposed model was validated on the Ninapro DB5 Dataset and the Myo Dataset. The classification accuracy of gesture recognition achieved good results.
SARS-CoV-2 has been spreading around the world for the past year. Recently, several variants such as B.1.1.7 (alpha), B.1.351 (beta), and P.1 (gamma), which share a key mutation N501Y on the ...receptor-binding domain (RBD), appear to be more infectious to humans. To understand the underlying mechanism, we used a cell surface-binding assay, a kinetics study, a single-molecule technique, and a computational method to investigate the interaction between these RBD (mutations) and ACE2. Remarkably, RBD with the N501Y mutation exhibited a considerably stronger interaction, with a faster association rate and a slower dissociation rate. Atomic force microscopy (AFM)-based single-molecule force microscopy (SMFS) consistently quantified the interaction strength of RBD with the mutation as having increased binding probability and requiring increased unbinding force. Molecular dynamics simulations of RBD-ACE2 complexes indicated that the N501Y mutation introduced additional π-π and π-cation interactions that could explain the changes observed by force microscopy. Taken together, these results suggest that the reinforced RBD-ACE2 interaction that results from the N501Y mutation in the RBD should play an essential role in the higher rate of transmission of SARS-CoV-2 variants, and that future mutations in the RBD of the virus should be under surveillance.
Graphite anodes show great potential for potassium storage, however, their capacity fades quickly owing to substantial interlayer expansion/shrinkage (i.e., up to 60%) induced structural degradation. ...Here, Ti3C2Tx MXene nanosheets are used as a fast electron/potassium‐ion dual‐function conductor to construct the framework of all‐integrated graphite nanoflake (GNF)/MXene (GNFM) electrodes. The continuous MXene framework constructs a 3D channel for fast electron/potassium‐ion transfer and endows GNFM electrodes with a high structural stability. Owing to this unique MXene framework, GNFM electrodes exhibit much enhanced potassium storage performances than that of the conventional polymer‐bonded electrodes even at high mass loadings. Moreover, GNFM electrodes also show impressive cyclability in non‐flammable electrolytes and are further used as anodes to assemble novel non‐flammable potassium‐ion capacitors that show an excellent cyclability and high energy/power densities (113.1 Wh kg–1 and 12.2 kW kg–1). New insights into phase transition mechanism in GNFM electrodes are verified by operando XRD. Density functional theory calculations demonstrate that MXene can promote electron transfer and potassium diffusion in the heterointerface between GNF and MXene. Therefore, the results demonstrate that all‐integrated GNFM electrodes designed with MXene as multifunctional frameworks provide a new paradigm for producing efficient potassium storage anodes.
Ti3C2Tx MXene nanosheets are used as a fast electron/potassium‐ion dual‐conductor to construct the framework of all‐integrated graphite nanoflake/MXene (GNFM) electrodes with improved electrochemical performances by exploiting unique MXene properties such as 2D morphology, metallic conductivity, and good flexibility. All‐integrated GNFM electrodes designed with MXene as multifunctional frameworks provide a new paradigm for producing efficient potassium storage anodes.
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