Design and Synthesis of a Novel PLK1 Inhibitor Scaffold Using a Hybridized 3D-QSAR Model

Polo-like kinase 1 (PLK1) plays an important role in cell cycle progression and proliferation in cancer cells. PLK1 also contributes to anticancer drug resistance and is a valuable target in anticancer therapeutics. To identify additional effective PLK1 inhibitors, we performed QSAR studies of two series of known PLK1 inhibitors and proposed a new structure based on a hybridized 3D-QSAR model. Given the hybridized 3D-QSAR models, we designed and synthesized 4-benzyloxy-1-(2-arylaminopyridin-4-yl)-1H-pyrazole-3-carboxamides, and we inspected its inhibitory activities to identify novel PLK1 inhibitors with decent potency and selectivity.     

Sensitivities of input parameters for predicting stability of soil slope

Bulletin of Engineering Geology and the Environment - The infinite slope stability model is the basis for predicting the slope stability; however, the fundamental theory requires various input...     

A Novel Lattice Reduction Precoding Method

In this work, a novel lattice reduction (LR) precoding method is proposed. The technique combines conventional LR precoding with a method of reducing the singular value coefficients of the LR-reduced basis matrix. The performance of the new technique was comparable to that of sphere encoding, while its complexity was lower than that of other sub-optimal methods.     

Micromechanical fracture modeling of asphalt concrete using a single-edge notched beam test

Cracks in asphalt pavements create irreversible structural and functional deficiencies that increase maintenance costs and decrease lifespan. Therefore, it is important to understand the fracture behavior of asphalt mixtures, which consist of irregularly shaped and randomly oriented aggregate particles and mastic. A two-dimensional clustered discrete element modeling (DEM) approach is implemented to simulate the complex crack behavior observed during asphalt concrete fracture tests. A cohesive softening model (CSM) is adapted as an intrinsic constitutive law governing material separation in asphalt concrete. A homogenous model is employed to investigate the mode I fracture behavior of asphalt concrete using a single-edge notched beam (SE(B)) test. Heterogeneous morphological features are added to numerical SE(B) specimens to investigate complex fracture mechanisms in the process zone. Energy decomposition analyses are performed to gain insight towards the forms of energy dissipation present in fracture testing of asphalt concrete. Finally, a heterogeneous model is used to simulate mixed-mode crack propagation.     

Ultra‐Adaptable and Wearable Photonic Skin Based on a Shape‐Memory,Responsive Cellulose Derivative

Photonic skins enable a direct and intuitive visualization of various physical and mechanical stimuli with eye‐readable colorations by intimately laminating to target substrates. Their development is still at infancy compared to that of electronic skins. Here, an ultra‐adaptable, large‐area (10 × 10 cm²), multipixel (14 × 14) photonic skin based on a naturally abundant and sustainable biopolymer of a shape‐memory, responsive multiphase cellulose derivative is presented. The wearable, multipixel photonic skin mainly consists of a photonic sensor made of mesophase cholesteric hydroxypropyl cellulose and an ultra‐adaptable adhesive layer made of amorphous hydroxypropyl cellulose. It is demonstrated that with multilayered flexible architectures, the multiphase cellulose derivative–based integrated photonic skin can not only strongly couple to a wide range of biological and engineered surfaces, with a maximum of ≈180 times higher adhesion strengths compared to those of the polydimethylsiloxane adhesive, but also directly convert spatiotemporal stimuli into visible color alterations in the large‐area, multipixel array. These colorations can be simply converted into 3D strain mapping data with digital camera imaging.     

Charge transport of alkanethiol self-assembled monolayers in micro-via hole devices

In this paper we fabricated 13440 microscale via hole structure devices using different length of alkanethiol self-assembled monolayers and characterized their electronic transport properties. Statistically averaged transport parameters such as current density, transport barrier height, effective electron mass, and transport decay coefficient were obtained from the great number of these devices. The yield of working microdevices was found as 1.5%. Temperature variable current-voltage characteristics for alkanethiol micro-via hole devices showed typical tunneling behavior when properly fabricated.     

An amphiphilic C60 penta-addition derivative as a new U-type molecular rectifier

Unimolecular rectification behavior of a known amphiphilic fullerene derivative, 1,4,11,15,30-pentakis(4-hydroxyphenyl)-2H-1,2,4,11,15,30-hexahydro-[60]fullerene, (4-HOC₆H₄)₅HC₆₀ (referred to here as the fullerene pentapod), is reported. The HOMO and LUMO energy levels of the pentapod were determined by density functional theory calculations (B3LYP/6-31G⁷). It was found that the HOMO of the donor moiety and the LUMO of the acceptor are in the same fullerene cage, quite unlike the fullerene derivatives so far reported as molecular rectifiers. The molecule formed a stable Langmuir-Blodgett film at the air–water interface. Characterization of the film indicated that it constitutes mostly a monolayer of molecules with the hydrophobic C₆₀ moiety pointing upwards. The LB film was transferred over Au(1 1 1) substrate and electrical conductivity of the film was measured by conducting atomic force microscopy. An asymmetric electrical rectification behavior was observed in the voltage range of ±1.0 V to ±2.0 V. Beyond a bias voltage of ±2.0 V, rectification ratio decreased steadily, until at ±2.5 V the current–voltage curve became symmetric. The observed electrical rectification behavior was ascribed to resonant electron tunneling between the Fermi level of the electrode and the molecular orbital levels of the fullerene pentapod. Charge transport in the preferred direction under a suitable applied bias was facilitated due to efficient electronic interactions of the molecular orbitals through a combined effect of homo- and peri-conjugation. This constitutes a new class of donor–acceptor system and a step forward in the field of molecular electronics.     

User Selection Method Adopting Cross-Entropy Method for a Downlink Multiuser MIMO System

This letter presents a novel method of user selection in a downlink multi-user multiple input multiple output (MU-MIMO) system employing the precoding procedures of zero forcing or block diagonalization (BD). The proposed technique utilizes the cross-entropy method (CEM) in order to maintain a performance level comparable to that of the full search (FS) method with reasonable complexity. With the CEM, the proposed system can select multiple users at once instead of selecting a single user at each step. From various computer simulations, it has been verified that the proposed method exhibits nearly 98 % of the sum-rate compared to the FS method, which implies that the proposed method far outperforms conventional methods such as semi-orthogonal user selection (SUS) or the capacity-based suboptimal user selection (CBSUS) algorithm. Compared to CBSUS, the proposed technique enhances the sum-rate by approximately 1.1 bps/Hz with about half the complexity when each user is equipped with two receiving antennas. In the case where each user is equipped with a single antenna, the proposed method outperforms the method of SUS by about 0.3 bps/Hz, at the expense of a complexity increase of $O(2M)$ times.     

Redox‐Induced Asymmetric Electrical Characteristics of Ferrocene‐Alkanethiolate Molecular Devices on Rigid and Flexible Substrates

The electrical properties of ferrocene‐alkanethiolate self‐assembled monolayers (SAMs) on a high yield solid‐state device structure are investigated. The devices are fabricated using a conductive polymer interlayer between the top electrode and the SAM on both silicon‐based rigid substrates and plastic‐based flexible substrates. Asymmetric electrical transport characteristics that originate from the ferrocene moieties are observed. In particular, a distinctive temperature dependence of the current (i.e., a decrease in current density as temperature increases) at a large reverse bias, which is associated with the redox reaction of ferrocene groups in the molecular junction, is found. It is further demonstrated that the molecular devices can function on flexible substrates under various mechanical stress configurations with consistent electrical characteristics. This study enhances the understanding of asymmetric molecules and may lead to the development of functional molecular electronic devices on both rigid and flexible substrates.