scholarly journals RECTANGULAR WAVE BEAM BASED GO/PO METHOD FOR RCS SIMULATION OF COMPLEX TARGET

2017 ◽  
Vol 53 ◽  
pp. 53-65 ◽  
Author(s):  
Wang-Qiang Jiang ◽  
Min Zhang ◽  
Ding Nie ◽  
Yong-Chang Jiao
IEEE Access ◽  
2021 ◽  
pp. 1-1
Author(s):  
Yuqi He ◽  
Sihan Lv ◽  
Luyu Zhao ◽  
Guan-Long Huang ◽  
Xiaoming Chen ◽  
...  

1956 ◽  
Vol 52 (3) ◽  
pp. 553-563 ◽  
Author(s):  
V. M. Papadopoulos

ABSTRACTThe scattering of the dominant transverse electric mode in an infinite perfectly conducting rectangular wave-guide by a semi-infinite resistive strip, centrally placed and parallel to the electric field, is calculated by the use of Laplace transforms. Formulae are derived for the amplitude of the scattered waves, and the numerical results, obtained using a digital computer, are given for various values of the surface resistivity of the strip.


2020 ◽  
Vol 14 (9) ◽  
pp. 980-987 ◽  
Author(s):  
Khaled Al‐Amoodi ◽  
Mohammad Mahdi Honari ◽  
Rashid Mirzavand ◽  
Jordan Melzer ◽  
Duncan G. Elliott ◽  
...  

2017 ◽  
Vol 42 (6) ◽  
pp. 1109 ◽  
Author(s):  
Jian Ning ◽  
Kezhen Han ◽  
Jingliang He ◽  
Yiran Wang ◽  
Hongkun Nie ◽  
...  

2015 ◽  
Vol 197 (18) ◽  
pp. 2908-2919 ◽  
Author(s):  
Anthony O. Gaca ◽  
Pavel Kudrin ◽  
Cristina Colomer-Winter ◽  
Jelena Beljantseva ◽  
Kuanqing Liu ◽  
...  

ABSTRACTThe bacterial stringent response (SR) is a conserved stress tolerance mechanism that orchestrates physiological alterations to enhance cell survival. This response is mediated by the intracellular accumulation of the alarmones pppGpp and ppGpp, collectively called (p)ppGpp. InEnterococcus faecalis, (p)ppGpp metabolism is carried out by the bifunctional synthetase/hydrolaseE. faecalisRel (RelEf) and the small alarmone synthetase (SAS) RelQEf. Although Rel is the main enzyme responsible for SR activation inFirmicutes, there is emerging evidence that SASs can make important contributions to bacterial homeostasis. Here, we showed that RelQEfsynthesizes ppGpp more efficiently than pppGpp without the need for ribosomes, tRNA, or mRNA. In addition to (p)ppGpp synthesis from GDP and GTP, RelQEfalso efficiently utilized GMP to form GMP 3′-diphosphate (pGpp). Based on this observation, we sought to determine if pGpp exerts regulatory effects on cellular processes affected by (p)ppGpp. We found that pGpp, like (p)ppGpp, strongly inhibits the activity ofE. faecalisenzymes involved in GTP biosynthesis and, to a lesser extent, transcription ofrrnBbyEscherichia coliRNA polymerase. Activation ofE. coliRelA synthetase activity was observed in the presence of both pGpp and ppGpp, while RelQEfwas activated only by ppGpp. Furthermore, enzymatic activity of RelQEfis insensitive to relacin, a (p)ppGpp analog developed as an inhibitor of “long” RelA/SpoT homolog (RSH) enzymes. We conclude that pGpp can likely function as a bacterial alarmone with target-specific regulatory effects that are similar to what has been observed for (p)ppGpp.IMPORTANCEAccumulation of the nucleotide second messengers (p)ppGpp in bacteria is an important signal regulating genetic and physiological networks contributing to stress tolerance, antibiotic persistence, and virulence. Understanding the function and regulation of the enzymes involved in (p)ppGpp turnover is therefore critical for designing strategies to eliminate the protective effects of this molecule. While characterizing the (p)ppGpp synthetase RelQ ofEnterococcus faecalis(RelQEf), we found that, in addition to (p)ppGpp, RelQEfis an efficient producer of pGpp (GMP 3′-diphosphate).In vitroanalysis revealed that pGpp exerts complex, target-specific effects on processes known to be modulated by (p)ppGpp. These findings provide a new regulatory feature of RelQEfand suggest that pGpp may represent a new member of the (pp)pGpp family of alarmones.


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