820 research outputs found
Spectral-Domain Computation of Fields Radiated by Sources in Non-Birefringent Anisotropic Media
We derive the key expressions to robustly address the eigenfunction
expansion-based analysis of electromagnetic (EM) fields produced by current
sources within planar non-birefringent anisotropic medium (NBAM) layers. In
NBAM, the highly symmetric permeability and permittivity tensors can induce
directionally-dependent, but polarization independent, propagation properties
supporting "degenerate" characteristic polarizations, i.e. four
linearly-independent eigenvectors associated with only two (rather than four)
unique, non-defective eigenvalues. We first explain problems that can arise
when the source(s) specifically reside within NBAM planar layers when using
canonical field expressions. To remedy these problems, we exhibit alternative
spectral-domain field expressions, immune to such problems, that form the
foundation for a robust eigenfunction expansion-based analysis of time-harmonic
EM radiation and scattering within such type of planar-layered media. Numerical
results demonstrate the high accuracy and stability achievable using this
algorithm.Comment: The official (preliminary) published version of this manuscript,
along with copyright information, can be found using the provided DOI. IEEE
Antennas Wireless Propag. Lett., 201
Decrease in gyrase A protein expression in _E. coli_ cells inhibited by antisense ribozymes
RNase P complexed with external guide sequence (EGS) represents a novel nucleic-acid-based gene interference approach to modulate gene expression. Nucleic acid-based gene interference technologies represent promising strategies for specific inhibition of mRNA sequences of choice. Recently, small interfering RNAs have been implicated in inducing endogenous RNase of the RNA-induced silencing complex in the RNA interference pathway to inhibit gene expression and growth of several human viruses. We report down regulation of protein expression of _E. coli_ gyrase A, an essential gene for DNA supercoiling and antibiotic susceptibility in BL21 (DE3) strain of _E. coli_, using Ribonuclease P based external guide sequence (EGS) technique. EGS directed against gyrase A gene that was cloned into pUC vector, which contains the ampicillin (Amp) resistance gene. The recombinant plasmid pT7EGyrA was transformed into BL21 (DE3) and inductions were performed using IPTG. Western blot was done to investigate the downregulation of gyrase A protein. The results showed a significant decrease of gyrase A suggesting the utility of EGS RNAs in gene therapy applications, by inhibiting the expression of essential proteins
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