On the possibility of superluminal energy propagation in a hyperbolic metamaterial of metal-dielectric layers

The energy propagation of electromagnetic fields in the effective medium of a one-dimensional photonic crystal consisting of dielectric and metallic layers is investigated. We show that the medium behaves like Drude and Lorentz medium, respectively, when the electric field is parallel and perpendicular to the layers. For arbitrary time-varying electromagnetic fields in this medium, the energy density formula is derived. We prove rigorously that the group velocity of any propagating mode obeying the hyperbolic dispersion must be slower than the speed of light in vacuum, taking into account the frequency dependence of the permittivity tensor. That is, it is not possible to have superluminal propagation in this dispersive hyperbolic medium consisting of real dielectric and metallic material layers. The propagation velocity of a wave packet is also studied numerically. This packet velocity is very close to the velocity of the propagating mode having the central frequency and central wave vector of the wave packet. When the frequency spread of the wave packet is not narrow enough, small discrepancy between these two velocities manifests, which is caused by the non-penetration effect of the evanescent modes. This work reveals that no superluminal phenomenon can happen in a dispersive anisotropic metamaterial medium made of real materials.Comment: 17 pages, 7 figure

Real-Time MIMO receiver for mode-division multiplexing over coupled-mode optical fibers

Today’s demand for increasing information transmission capacity has led us to develop new technologies to beat the theoretical capacity limit. Among these, advances in digital fiber-optic communication have been a especially promising approach to achieve such target because of the high speed of light and its multiple physical dimensions to take advantage of. This project aims to apply and expand our knowledge acquired in the first introductory course in signal theory to understand how real world digital communication systems work. In particular, we will focus on the multiple-input multiple-output (MIMO) digital signal processing (DSP) part of the digital fiber-optic communicatio

Effect of Bacteria on Airway Submucosal Glands Liquid Secretion in Swine

Cystic fibrosis (CF) is a genetic disorder caused by mutations in the gene encoding for the cystic fibrosis transmembrane conductance regulator (CFTR) anion channel. Currently, more than 4,100 Canadians have CF. The major cause of CF morbidity and mortality is airway disease, for which there is no cure. The events leading from CFTR gene mutation to CF airway disease are not fully understood, and there is controversy regarding the primary defect responsible for CF airway disease pathogenesis. Newborn CFTRΔF508/ΔF508 and CFTR-/- swine show no sign of infection and inflammation in the lung but suffer from defective bacteria eradication caused by abnormal innate immune system. The cornerstone of the airway’s innate immune defense is mucociliary clearance, which relies on the normal regulation of airway surface liquid (ASL), which covers the airway epithelium. It has been hypothesized that abnormal ASL is the primary defect that leads to the failure of the airway innate immune defense in CF. Evidence show that the airway submucosal gland functions abnormally in both CF patients and in animal models of CF. This is not surprising since airway submucosal glands normally express CFTR. However, the function of the gland in health and disease is not fully understood. The response of airway submucosal gland to inhaled bacteria has never been tested and its ion transport properties have not been fully described. Our objective is to investigate the effect of inhaled bacteria on airway submucosal gland secretion, and to study and compare the function of different segments of airway submucosal gland in wild-type and CF airway. Knowledge generated by this thesis would help better understand CF airway pathophysiology and may contribute to improving treatment methods

Diastereoselective three-component synthesis of beta-amino carbonyl compounds using diazo compounds, boranes, and acyl imines under catalyst-free conditions

Diazo compounds, boranes, and acyl imines undergo a three-component Mannich condensation reaction under catalyst-free conditions to give the anti β-amino carbonyl compounds in high diastereoselectivity. The reaction tolerates a variety of functional groups, and an asymmetric variant was achieved using the (−)-phenylmenthol as chiral auxiliary in good yield and selectivity. These β-amino carbonyl compounds are valuable intermediates, which can be transformed to many potential bioactive molecules.We gratefully acknowledge Philip N. Moquist for editorial review of the manuscript. Preliminary experiments were performed by Y.L. at Boston University. Completion of the work was accomplished under the direction of G.W. at the University of Science and Technology Beijing, China. S.E.S. and Y.L. gratefully acknowledge the NIH for support (NIGMS R01 GM078240). Y.L., J.Y., and G.W. thank the Innovative Foundation from China National Petroleum Corporation (Grant No. 2012D-5006-0504) for financial support. Y.L. also thanks the Beijing Natural Science Foundation (Grant No. 2144052) and China Postdoctoral Science Foundation (2013M540859) for financial support. (NIGMS R01 GM078240 - NIH; 2012D-5006-0504 - Innovative Foundation from China National Petroleum Corporation; 2144052 - Beijing Natural Science Foundation; 2013M540859 - China Postdoctoral Science Foundation)Published versio

Effect of Earth's rotation on the trajectories of free-fall bodies in Equivalence Principle Experiment

Owing to Earth's rotation a free-fall body would move in an elliptical orbit rather than along a straight line forward to the center of the Earth. In this paper on the basis of the theory for spin-spin coupling between macroscopic rotating bodies we study violation of the equivalence principle from long-distance free-fall experiments by means of a rotating ball and a non-rotating sell. For the free-fall time of 40 seconds, the difference between the orbits of the two free-fall bodies is of the order of 10^{-9}cm which could be detected by a SQUID magnetometer owing to such a magnetometer can be used to measure displacements as small as 10^{-13} centimeters.Comment: 6 pages, 4 figure

Calcineurin B-Like Proteins CBL4 and CBL10 Mediate Two Independent Salt Tolerance Pathways in Arabidopsis.

In Arabidopsis, the salt overly sensitive (SOS) pathway, consisting of calcineurin B-like protein 4 (CBL4/SOS3), CBL-interacting protein kinase 24 (CIPK24/SOS2) and SOS1, has been well defined as a crucial mechanism to control cellular ion homoeostasis by extruding Na+ to the extracellular space, thus conferring salt tolerance in plants. CBL10 also plays a critical role in salt tolerance possibly by the activation of Na+ compartmentation into the vacuole. However, the functional relationship of the SOS and CBL10-regulated processes remains unclear. Here, we analyzed the genetic interaction between CBL4 and CBL10 and found that the cbl4 cbl10 double mutant was dramatically more sensitive to salt as compared to the cbl4 and cbl10 single mutants, suggesting that CBL4 and CBL10 each directs a different salt-tolerance pathway. Furthermore, the cbl4 cbl10 and cipk24 cbl10 double mutants were more sensitive than the cipk24 single mutant, suggesting that CBL10 directs a process involving CIPK24 and other partners different from the SOS pathway. Although the cbl4 cbl10, cipk24 cbl10, and sos1 cbl10 double mutants showed comparable salt-sensitive phenotype to sos1 at the whole plant level, they all accumulated much lower Na+ as compared to sos1 under high salt conditions, suggesting that CBL10 regulates additional unknown transport processes that play distinct roles from the SOS1 in Na+ homeostasis