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Manami Iizuka, Yuto Nakagawa, Kyohei Ohmura, Eiichi Satou, Atsuhiro Fujimori
The formation of a nanofiber morphology at the mesoscopic scale and the molecular-level packing of a gemini-type amphiphilic diamide derivative with two hydrocarbons were investigated from two perspectives. First, it was confirmed that a diamide derivative with two hydrocarbons forms crystalline nanofibers even in a monomolecular layer. The height, thickness, and lattice spacing of the two-dimensional orthorhombic system of this crystalline nanofiber in the monolayer of a diamide derivative with two hydrocarbons are 5, 30, and 0...
March 4, 2017: Journal of Colloid and Interface Science
Yangmei Chen, Hua Y Geng, Xiaozhen Yan, Yi Sun, Qiang Wu, Xiangrong Chen
Hydrogen-rich compounds are important for understanding the dissociation of dense molecular hydrogen, as well as searching for room temperature Bardeen-Cooper-Schrieffer (BCS) superconductors. A recent high pressure experiment reported the successful synthesis of novel insulating lithium polyhydrides above 130 GPa. However, the results are in sharp contrast to a previous theoretical prediction by the PBE functional that around this pressure range all lithium polyhydrides (LiHn (n = 2-8)) should be metallic...
March 20, 2017: Inorganic Chemistry
Yuanxin Tian, Yonghuan Yu, Yudong Shen, Hua Wan, Shan Chang, Tingting Zhang, Shanhe Wan, Jiajie Zhang
ROS1 and ALK are promising targets of anti-cancer drugs for non small cell lung cancer. Since they have 49% amide acid sequence homology in the kinases domain and 77% identity at the ATP binding area, some ALK inhibitors also showed some significant responses for ROS1 in the clinical trial, such as the type-I binding inhibitor crizotinib and PF-06463922. As a newly therapeutic target, selective ROS1 inhibitor is relative rarely. Moreover, the molecular basis for the selectivity of ROS1 versus ALK still remains unclear...
March 20, 2017: Journal of Chemical Information and Modeling
Seho Yi, Jin-Ho Choi, Hyun-Jung Kim, Chul Hong Park, Jun-Hyung Cho
Chemical modification of graphene with adatoms is of importance for nanoelectronics applications. Based on first-principles density-functional theory calculations including van der Waals interactions, we present a comparative study of the diffusion characteristics of oxygen (O) and fluorine (F) atoms both on graphene and between the layers of bilayer graphene. We find that the calculated diffusion barrier for the O atom increases slightly from 0.81 eV on graphene to 0.85 eV within bilayer graphene, while that for the F atom largely decreases from 0...
March 20, 2017: Physical Chemistry Chemical Physics: PCCP
Wanshun Xia, Liping Dai, Peng Yu, Xin Tong, Wenping Song, Guojun Zhang, Zhiming Wang
Following the development of many novel two-dimensional (2D) materials, investigations of van der Waals heterojunctions (vdWHs) have attracted significant attention due to their excellent properties such as smooth heterointerface, highly gate-tunable bandgap, and ultrafast carrier transport. Benefits from the atom-scale thickness, physical and chemical properties and ease of manipulation of the heterojunctions formulated by weak vdW forces were demonstrated to indicate their outstanding potential in electronic and optoelectronic applications, including photodetection and energy harvesting, and the possibility of integrating them with the existing semiconductor technology for the next-generation electronic and sensing devices...
March 20, 2017: Nanoscale
Mudar Ahmed Abdulsattar
In the present work, we applied density functional theory and temperature-dependent Gibbs free energy calculations to wurtzoid structures to explain the sensitivity of ZnO nanocrystals towards chlorine molecules. In agreement with experimental findings, our results revealed that chlorine sensing under ambient conditions is feasible. Higher temperatures increased the sensitivity of ZnO nanocrystals towards chlorine gas molecules. Peak calculated sensitivities were in the temperature ranges (167-220 °C), (447-578 °C) and (952-1159 °C), which is in good agreement with experimentally determined temperatures...
April 2017: Journal of Molecular Modeling
Sai Murali R S, Sai Siddhardha R S, Rajesh Babu D, Venketesh S, Basavaraju R, Nageswara Rao G
The present study brings out the interaction between vasicine, an alkaloid and Adhatoda vasica Nees with double stranded DNA. The physico-chemical interaction between small molecules and nucleic acids is a major area of focus in screening drugs against various cancers. Molecular probing in our study using Molecular Operating Environment (MOE) has revealed interaction of vasicine with DNA double helix. Here we report the interaction of vasicine with Calf thymus DNA. We present for the first time the results obtained from UV-visible, fluorescence spectroscopic and differential scanning calorimetric techniques that suggest a moderate to strong electrostatic, hydrophobic and van der Waals interactions mediating the DNA binding properties of vasicine, leading to disruption of DNA secondary structure...
March 8, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Sergio A Hassan
Nanoparticle (NP) aggregation can lead to prolonged retention in tissues or embolism, among other adverse effects. Successful use in biomedicine thus requires the capability to make NPs with limited aggregative potential. Rational design is presently a challenge due to incomplete knowledge of their interactions in biofluids. Recently, ultrasmall gold NPs passivated with endogenous antioxidant glutathione have shown promise for use in vivo. Computer simulations are here conducted to identify the forces underlying aggregation (or lack thereof) of these NPs in a cell culture...
March 17, 2017: ACS Nano
Abin Varghese, Chithra H Sharma, Madhu Thalakulam
A generic and universal layer engineering strategy for van der Waals (vW) materials, scalable and compatible with the current semiconductor technology, is of paramount importance in realizing all-two-dimensional logic circuits and to move beyond the silicon scaling limit. In this letter, we demonstrate a scalable and highly controllable microwave plasma based layer engineering strategy for MoS2 and other vW materials. Using this technique we etch MoS2 flakes layer-by-layer starting from an arbitrary thickness and area down to the mono- or the few-layer limit...
March 17, 2017: Nanoscale
Ruoqi Ai, Xun Guan, Jia Li, Kangkang Yao, Peng Chen, Zhengwei Zhang, Xidong Duan, Xiangfeng Duan
Two-dimensional layered materials (2DLMs) have attracted considerable recent interest for their layer-number-dependent physical and chemical properties, as well as potential technological opportunities. Here we report the synthesis of two-dimensional layered cadmium iodide (CdI2) nanoplates using a vapor transport and deposition approach. Optical microscopy and scanning electron microscopy studies show that the resulting CdI2 nanoplates predominantly adopt hexagonal and triangular morphologies with a lateral dimension of ∼2-10 μm...
March 17, 2017: ACS Nano
Shuai Wang, Iker Agirrezabal-Telleria, Aditya Bhan, Dante Simonetti, Kazuhiro Takanabe, Enrique Iglesia
This account illustrates concepts in chemical kinetics underpinned by the formalism of transition state theory using catalytic processes that enable the synthesis of molecules suitable as fuels from C1 and oxygenate reactants. Such feedstocks provide an essential bridge towards a carbon-free energy future, but their volatility and low energy density require the formation of new C-C bonds and the removal of oxygen. These transformations are described here through recent advances in our understanding of the mechanisms and site requirements in catalysis by surfaces, with emphasis on enabling concepts that tackle ubiquitous reactivity and selectivity challenges...
March 16, 2017: Faraday Discussions
Michael P Ziemkiewicz, Christian Pluetzer, Michael Wojcik, Jérôme Loreau, Ad van der Avoird, David J Nesbitt
Vibrationally state selective overtone spectroscopy and dynamics of weakly bound Ne-H2O complexes (D0((para)) = 31.67 cm(-1), D0((ortho)) = 34.66 cm(-1)) are reported for the first time, based on near infrared excitation of van der Waals cluster bands correlating with vOH = 2 ← 0 overtone transitions (|02(-)⟩←|00(+)⟩ and |02(+)⟩←|00(+)⟩) out of the ortho (101) and para (000) internal rotor states of the H2O moiety. Quantum theoretical calculations for nuclear motion on a high level ab initio potential energy surface (CCSD(T)/VnZ-f12 (n = 3,4), corrected for basis set superposition error and extrapolated to the complete basis set limit) are employed for assignment of Σ←Σ,Π←Σ, and Σ←Π infrared bands in the overtone spectra, where Σ(K = 0) and Π (K = 1) represent approximate projections (K) of the body angular momentum along the Ne-H2O internuclear axis...
March 14, 2017: Journal of Chemical Physics
Moupriya Das, Anthony B Costa, Jason R Green
According to the van der Waals picture, attractive and repulsive forces play distinct roles in the structure of simple fluids. Here, we examine their roles in dynamics; specifically, in the degree of deterministic chaos using the Kolmogorov-Sinai (KS) entropy rate and the spectra of Lyapunov exponents. With computer simulations of three-dimensional Lennard-Jones and Weeks-Chandler-Andersen fluids, we find repulsive forces dictate these dynamical properties, with attractive forces reducing the KS entropy at a given thermodynamic state...
February 2017: Physical Review. E
Wahib Aggoune, Caterina Cocchi, Dmitrii Nabok, Karim Rezouali, Mohamed Akli Belkhir, Claudia Draxl
By investigating the optoelectronic properties of prototypical graphene/hexagonal boron nitride (h-BN) heterostructures, we demonstrate how a nanostructured combination of these materials can lead to a dramatic enhancement of light-matter interaction and give rise to unique excitations. In the framework of ab initio many-body perturbation theory, we show that such heterostructures absorb light over a broad frequency range, from the near-infrared to the ultraviolet (UV), and that each spectral region is characterized by a specific type of excitations...
March 20, 2017: Journal of Physical Chemistry Letters
Mark S Miller, Wesley Kayser Lay, Shuxiang Li, William Charles Hacker, Jiadi An, Jianlan Ren, Adrian Hamilton Elcock
There is a small, but growing, body of literature describing the use of osmotic coefficient measurements to validate and reparameterize simulation force fields. Here we have investigated the ability of five very commonly used force field and water model combinations to reproduce the osmotic coefficients of seven neutral amino acids and five small molecules. The force fields tested include AMBER ff99SB-ILDN, CHARMM36, GROMOS54a7, and OPLS-AA, with the first of these tested in conjunction with the TIP3P and TIP4P-Ew water models...
March 15, 2017: Journal of Chemical Theory and Computation
Hui Zhu, Qingxiao Wang, Chenxi Zhang, Rafik Addou, Kyeongjae Cho, Robert M Wallace, Moon J Kim
A novel phase transition, from multilayered 2H-MoTe2 to a parallel bundle of sub-nanometer-diameter metallic Mo6 Te6 nanowires (NWs) driven by catalyzer-free thermal-activation (400-500 °C) under vacuum, is demonstrated. The NWs form along the 〈11-20〉 2H-MoTe2 crystallographic directions with lengths in the micrometer range. The metallic NWs can act as an efficient hole injection layer on top of 2H-MoTe2 due to favorable band-alignment. In particular, an atomically sharp MoTe2 /Mo6 Te6 interface and van der Waals gap with the 2H layers are preserved...
March 10, 2017: Advanced Materials
Yuwei Wang, Rui Han, Huimin Zhang, Hongli Liu, Jiazhong Li, Huanxiang Liu, Paola Gramatica
The antiandrogens, such as bicalutamide, targeting the androgen receptor (AR), are the main endocrine therapies for prostate cancer (PCa). But as drug resistance to antiandrogens emerges in advanced PCa, there presents a high medical need for exploitation of novel AR antagonists. In this work, the relationships between the molecular structures and antiandrogenic activities of a series of 7α-substituted dihydrotestosterone derivatives were investigated. The proposed MLR model obtained high predictive ability...
2017: BioMed Research International
C G de Waal, G J Hutten, J V Kraaijenga, F H de Jongh, A H van Kaam
OBJECTIVE: To determine if the electrical activity of the diaphragm, as measure of neural respiratory drive and breathing effort, changes over time in preterm infants transitioned from nasal continuous positive airway pressure (nCPAP) to high flow nasal cannula (HFNC). DESIGN: Prospective observational study. SETTING: Neonatal intensive care unit. PATIENTS: Stable preterm infants transitioned from nCPAP to HFNC using a 1:1 pressure to flow ratio...
March 14, 2017: Archives of Disease in Childhood. Fetal and Neonatal Edition
Manh-Ha Doan, Youngjo Jin, Subash Adhikari, Sanghyub Lee, Jiong Zhao, Seong Chu Lim, Young Hee Lee
Despite numerous studies on two-dimensional van der Waals heterostructures, a full understanding of the charge transport and photoinduced current mechanisms in these structures, in particular, associated with charge depletion/inversion layers at the interface remains elusive. Here, we investigate transport properties of a prototype multilayer MoS2/WSe2 heterojunction via a tunable charge inversion/depletion layer. A charge inversion layer was constructed at the surface of WSe2 due to its relatively low doping concentration compared to that of MoS2, which can be tuned by the back-gate bias...
March 20, 2017: ACS Nano
Junfeng Gao, Gang Zhang, Yong-Wei Zhang
Currently, a major hurdle preventing phosphorene from various electronic applications is its rapid oxidation under ambient conditions. Thus how to enhance its chemical stability by suppressing oxidation becomes an urgent task. Here, we reveal a highly effective procedure to suppress the oxidation of phosphorene by employing a suitable van der Waals (vdW) substrate and a vertical electric field. Our first-principles study shows that the phosphorene-MoSe2 vdW heterostructure is able to reverse the stability of physisorption and chemisorption of molecular O2 on phosphorene...
March 14, 2017: Nanoscale
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