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Kết quả tìm kiếm
In this paper, we extend our investigation of the validity of the cosmic no-hair conjecture within non-canonical anisotropic inflation. As a result, we are able to figure out an exact Bianchi type I solution to a power-law {\it k}-inflation model in the presence of unusual coupling between scalar and electromagnetic fields as −f2(ϕ)FμνFμν/4. Furthermore, stability analysis based on the dynamical system method indicates that the obtained solution does admit stable and attractive hairs during an inflationary phase and therefore violates the cosmic no-hair conjecture. |
Multistability is a critical property of nonlinear dynamical systems, where a variety of phenomena such as coexisting attractors can appear for the same parameters but with different initial conditions. The flexibility in the system’s performance can be achieved without changing parameters. Complex dynamics have been observed in multistable systems, and we have witnessed systems with multistability in numerous fields ranging across physics, biology, chemistry, electronics, and mechanics, as well as reported applications in oscillators and secure communications. It is now well established from a variety of studies that multistable systems are very sensitive to both random noise and perturbations. Numerous studies such as open-loop control, feedback control, adaptive control, intellig... |
Ten active principles (compounds 1-10) have been isolated following protein tyrosine phosphatase 1B (PTP1B) assay-guided fractionation of the methanol extract of the root of Polygonum cuspidatum. The chemical structures of the compounds were characterized mainly by nuclear magnetic resonance (NMR) spectroscopic and physicochemical data. This is the first time that 9,10-anthraquinones (compounds 5-6) have been isolated from P. cuspidatum, and this is the first record of compound 9 from the genus Polygonum. Except for compound 4, all the isolates showed potential inhibitory activity against PTP1B with half-maximal inhibitory concentration IC50 values ranging from 6.3 to 28.9 µM. Furthermore, a kinetic study indicated mixed-competitive inhibition with PTP1B for compounds 2 and 9 and no... |
We theoretically investigate the plasmonic properties of mid-infrared graphene-based metamaterials and apply deep learning of a neural network for the inverse design. These artificial structures have square periodic arrays of graphene plasmonic resonators deposited on dielectric thin films. Optical spectra vary significantly with changes in structural parameters. To validate our theoretical approach, we carry out finite difference time domain simulations and compare computational results with theoretical calculations. Quantitatively good agreements among theoretical predictions, simulations, and previous experiments allow us to employ this proposed theoretical model to generate reliable data for training and testing deep neural networks. By merging the pre-trained neural network wit... |
Compressive sampling (CS) has been commonly employed in the field of magnetic
resonance imaging (MRI) to accurately reconstruct sparse and compressive signals. In a MR image,
a large amount of encoded information focuses on the origin of the k-space. For the 2D Cartesian
K-space MRI, under-sampling the frequency-encoding (kx) dimension does not affect to the
acquisition time, thus, only the phase-encoding (ky) dimension can be exploited. In the traditional
random under-sampling approach, it acquired Gaussian random measurements along the phaseencoding (ky) in the k-space. In this paper, we proposed a hybrid under-sampling approach; the
number of measurements in (ky) is divided into two portions: 70% of the measurements are for
random under-sampling and 30% are for definite un... |
Compression effects on alpha and beta relaxation process of amorphous drugs are theoretically investigated by developing the elastically collective nonlinear Langevin equation theory. We describe the structural relaxation as a coupling between local and nonlocal activated process. Meanwhile, the secondary beta process is mainly governed by the nearest-neighbor interactions of a molecule. This assumption implies the beta relaxation acts as a precursor of the alpha relaxation. When external pressure is applied, a small displacement of a molecule is additionally exerted by a pressure-induced mechanical work in the dynamic free energy, which quantifies interactions between a molecule with its nearest neighbors. The local dynamics has more restriction and it induces stronger effects of c... |
The detection of volatile organic compounds (VOCs) is very important in practical application in breath analysis. Thus, gas sensors based on metal oxide have been fabricated, but they lacked selectivity. One approach to resolve this task is to use array of highly sensitive and selective sensors as an electronic nose. Here we present a gas sensor array of Tin oxide nano-structure use of temperature modulation techniques. A Platinum micro-heater is accompanied with the array gas sensor. The gas sensor array was composing of five single sensors and that single sensor is located at different site from the micro heater and work at different temperatures. The gas sensing properties of the gas array sensors was investigated with VOC gases such as Ethanol, Methanol, Iso-propanol, and Aceton... |
Polyproline II helix (PPII) is one of the secondary structures in proteins that play an important role in various biological processes. In this study, we have developed a new macrocyclization strategy that efficiently reinforces a model tetrapeptide into a PPII structure. We also elucidated some relationships between structural features and PPII stability in this model. This new macrocyclic stapling strategy can serve as a useful chemical tool to manipulate the PPII structure for various applications. |
Bacterial exopolysaccharides (EPSs) are an essential group of compounds secreted by bacteria. These versatile EPSs are utilized individually or in combination with different materials for a broad range of biomedical field functions. The various applications can be explained by the vast number of derivatives with useful properties that can be controlled. This review offers insight on the current research trend of nine commonly used EPSs, their biosynthesis pathways, their characteristics, and the biomedical applications of these relevant bioproducts. |
In recent decades, drastic changes in global social-economic situations have led to significant shifts in the financial market for entrepreneurial firms, thus resulting in changes in entrepreneurial finance discipline. The current body of literature, despite its significant growth, has not provided an overview landscape of this research area. Consequently, this study aims to fill this gap by employing the bibliometric analysis of 6902 articles from 1970 to 2019 extracted from the Web of Science database. By doing so, this paper attempts to provide an overview of the discipline's research output, social and conceptual structure, and offer strategies facilitating the scientific development within the field. The findings indicate that entrepreneurial finance is a young and growing fiel... |
