Seeing the Unseen: Experimental Observation of Magnetic Anapole State Inside a High-Index Dielectric Particle

The existence of non-radiating electromagnetic sources attracts much attention in photonic community and gives rise to extensive discussions of various applications in lasing, medical imaging, sensing, and nonlinear optics. In this article, the existence of magnetic anapole states (or magnetic-type non-radiating sources) characterized by a suppressed magnetic dipole radiation in a dielectric cylindrical particle is theoretically predicted and experimentally demonstrated. The specific features of the magnetic anapole state under ideal conditions are identified, followed by a demonstration of how their existence can be detected in practical structures. The concept is valid in various frequency bands from visible range for nanoparticles to microwave range for millimeter size objects. The experimental study is performed in microwave frequency range which allows not only to measure the far-field (scattered field) characteristics, but also to probe the peculiar field profile directly inside the dielectric particle. The experimental results agree well with the analytical ones and pave the way to detect and identify nontrivial different-type anapole states.     

Investigation of MHD effect on nanofluid heat transfer in microchannels

Journal of Thermal Analysis and Calorimetry - An incompressible preconditioned lattice Boltzmann method (IPLBM) is proposed to investigate the fluid flow and heat transfer characteristics of...     

Synthesis of Novel 3-(5-(Alkyl/arylthio)-1,3,4-Oxadiazol-2-yl)-8-Phenylquinolin-4(1H)-One Derivatives as Anti-HIV Agents

Novel quinolone derivatives featuring an 1,3,4-oxadiazole ring as a metal-chelating component and a benzyl group base on HIV-1 integrase inhibitors pharmacophore were designed and synthesized. An antiviral assay revealed that most analogues inhibited HIV-1 replication in the cell culture. Our results showed that compounds bearing small alkyl groups as R group were inactive in anti-HIV-1 assay, whereas compounds possessing benzyl or substituted benzyl at the same position showed good anti-HIV activity with the range of 20–57% at 100 μM concentration. Among them, 3-(5-((2-fluorobenzyl)thio)-1,3,4-oxadiazol-2-yl)-8-phenylquinolin-4-(1H)-one (compound 13) showed reasonable cell-based antiviral activity (EC₅₀ = 50 μM) with no considerable cytotoxicity (CC₅₀ > 100 μM) in the cell viability assay, suggesting that it may be amenable to further development for identifying new anti-HIV-1 agents. Docking studies using the later crystallographic data available for PFV integrase corroborate favorable binding to the active site of HIV integrase, providing a basis for the design of more potent analogues.     

Dynamic glottal pressures in an excised hemilarynx model

During phonation, air pressures act upon the vocal folds to help maintain their oscillation. The air pressures vary dynamically along the medial surface of the vocal folds, although no live human or excised studies have shown how those pressure profiles vary in time. The purpose of this study was to examine time-dependent glottal pressure profiles using a canine hemilarynx approach. The larynx tissue was cut in the midsaggital plane from the top to about 5 mm below the vocal folds. The right half was replaced with a Plexiglas pane with imbedded pressure taps. Simultaneous recordings were made of glottal pressure signals, subglottal pressure, particle velocity, and average airflow at various levels of adduction. The data indicate that the pressures in the glottis (on the Plexiglas) vary both vertically and longitudinally throughout the phonatory cycle. Pressures vary most widely near the location of maximum vibratory amplitude, and can include negative pressures during a portion of the cycle. Pressures anterior and posterior to the maximum amplitude location may have less variation and may remain positive throughout the cycle, giving rise to a new concept called dynamic bidirectional pressure gradients in the glottis. This is an important concept that may relate strongly to tissue health as well as basic oscillatory mechanics.     

Swampland dS conjecture in mimetic f(R,T) gravity

In this paper, we study a theory of gravity called mimetic f(R, T) in the presence of swampland dS conjecture. For this purpose, we introduce several inflation solutions of the Hubble parameter H(N) from f(R, T) = R + δT gravity model, in which R is Ricci scalar, and T denotes the trace of the energy–momentum tensor. Also, δ and N are the free parameter and a number of e-fold, respectively. Then we calculate quantities such as potential, Lagrange multiplier, slow-roll, and some cosmological parameters such as n_s and r. Then we challenge the mentioned inflationary model from the swampland dS conjecture. We discuss the stability of the model and investigate the compatibility or incompatibility of this inflationary scenario with the latest Planck observable data.     

The direct effect of interfacial nanolayers on thermal conductivity of nanofluids

One of the most important features of nanofluids is their thermal conductivity. In this article, a new model for thermal conductivity is proposed based on the combination of a statistical model and thermal convection caused by Brownian motion of nanoparticles with considering the effect of interfacial nanolayers among nanoparticles and base fluids. This model is compared with Al₂O₃ in deionized water and CuO in deionized water (based nanofluids of spherical particles) using a number of theoretical and experimental thermal conductivity models, after that the experimental results have been made available in the open literature. In this model, an interfacial nanolayer is influenced directly on both parts of static and dynamic effective thermal conductivity. The present model shows good agreement with the experimental result of nanofluids and gives better predictions compared to models used for nanofluids in this article. This model is purely theoretical and in order to achieve it, experimental results have no effect.     

Microwave‐assisted synthesis of 1‐hydrazinophosphonates via the reaction of aldazines with dialkyl phosphite

A simple, efficient, and novel method has been developed for the synthesis of 1‐hydrazinophosphonic acids from aldazines. As described below, treatment of aldazines with diethyl phosphite gives the corresponding 1‐hydrazinophosphonic acids in good yields. The reaction proceeds under microwave irradiation at 110°C and neutral condition without any additives such as base, acid, or catalyst. This method is easy, rapid, and gives good yields for the 1‐hydrazinophosphonic acids. © 2012 Wiley Periodicals, Inc. Heteroatom Chem 23:304–308, 2012; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.21019     

Analysis of Microscopic Displacement Mechanisms of a MIOR Process in Porous Media with Different Wettability

Transport in Porous Media - The wettability of the reservoir rock has an important effect on the displacement of fluids on a microscopic scale in all EOR processes, especially in the microbial...     

Palladium-catalyzed domino protodecarboxylation/oxidative Heck reaction: regioselective arylation of coumarin-3-carboxylic acids

A protocol for straightforward and step-economical synthesis of neoflavones from coumarin-3-carboxylic acids is developed. This approach enables controlled protodecarboxylation/regioselective C–H arylation of coumain-3-carboxylic acids in one-pot using a monometallic catalytic system. A wide variety of electron-donating and -withdrawing substituents on both coumarins and arylboronic acid are tolerated under the reaction conditions and 4-aryl coumarins are constructed in high yields.     

Anionic behavior and single-molecule crystal in fullerene confinements: A contribution from DFT energy decomposition and cooperativity analyses

The recently proposed systems of various anions (A) confined inside C₆₀ , A⁻ @ C₆₀ , which in turn behave as large and stable anions, (A @ C₆₀)⁻ , can find potential applications in various fields. On the other hand, it has earlier been shown that from the dihalogens (X₂ ) encapsulated C₆₀ , X₂ @ C₆₀ , only F₂ @ C₆₀ can be introduced as a system in which the cage acts as a cation C₆₀⁺ and interacts with an endohedral anion, F₂⁻ , forming the F₂⁻ @ C₆₀⁺ as a single-molecule crystal compound. In this work, two density functional theory energy decomposition analysis (EDA) schemes, where in one of them the noninteracting kinetic, electrostatic, and exchange-correlation energies come into play while another scheme, called as EDA-SBL, includes the steric, electrostatic, and quantum effects as essential ingredients (S. Liu, J. Chem. Phys. 2007 , 126, 244103), are utilized to find out what energetic components govern the unique characteristics of the (A @ C₆₀)⁻ and X₂ @ C₆₀ confinements. It is shown that the noninteracting kinetic energy and steric energies have important contributions to the total interaction energies for the considered systems. However, there are other confinements for which the electrostatic and exchange-correlation contributions play also imperative roles. Furthermore, we find reasonable correlations between interaction energies and their components as well as the energetic components themselves, leading to an alternative EDA scheme including the noninteracting kinetic, steric, and electrostatic energies for investigations on other endohedral fullerenes. Extending our analyses to large size confinements, Cl⁻ @ C_n with n up to 90 as illustrative examples, the quantitative cooperativity concept is also explored, where the positive and negative cooperativity profiles unveil a specific size of the anionic confinements to form the most stable large anion.