In the 1- (4-fluorophenyl) -2,3-dihydro-1 H-naphto- [1 and 2-e] [1 and 3] oxazine-3-n, there are 4 rings, respectively, rings from the side attached to the halogen They are named C, B, A, and D. Calculations and studies show that the amount of aromatics in the halogen-ring A in all cases has the highest number. In the B loop, the predicted aromatism level is zero, and in the ring C and D, relat...

a module $m$ is said to be coretractable if there exists a nonzero homomorphism of every nonzero factor of $m$ into $m$. we prove that all right (left) modules over a ring are coretractable if and only if the ring is morita equivalent to a finite product of local right and left perfect rings.

congenital anomalies of the great thoracic vessels have been reported in 20% of dogs and cats. in some cases, the vascular ring anomalies remain unrecognized throughout the lifetime of an animal. this report describes a case with an unusual vascular ring anomaly (vra) that was detected during dissection on a cadaver of an approximately two-year-old male native mixed breed dog. no history of the...

acanthamoeba keratitis is a vision- threatening infection and the most important risk factors are contact lenses characteristic symptoms include disproportionately severe ocular pain, epithelial ulcer, ring stromal infiltrate and resistance to antimicrobial treatment. the aim is to report the first cases of acanthamoeba keratitis in yazd in a retrospective study confirmed on histopathological a...

ring cleavage occurred when 1,2,4-triazino-1,2,4-triazines (3), (4) and (5) were treated with concentrated hydrochloric acid to yield n-substituted triazines (7) and (8). these confirm the given configuration assigned to the isomeric triazinotriazines. 6-methyl-2-phenyl-7h-oxazolo [3,2-b][1,2,4]-triazin-7-one (9) underwent ring cleavage on treatment with sodium alkoxide to afford 3-alkoxy-1,2,4...

in this paper, we construct two fuzzy sets using the notions of level subsets and strong level subsets of a given fuzzy set in a ring r. these fuzzy sets turn out to be identical and provide a universal construction of a fuzzy ideal generated by a given fuzzy set in a ring. using this construction and employing the technique of strong level subsets, we provide the shortest and direct fuzzy set ...

Nitro-containing heteroaromatic derivatives structurally related to nitroimidazole (Metronidazole) are being extensively evaluated against Helicobacter pylori isolates. On the other hand, 1,3,4-thiadiazole derivatives have also demonstrated promising antibacterial potential. In present study, we evaluated anti-H. pylori activity of novel hybrid molecules bearing nitroaryl and 1,3,4-thiadiazole ...

let $r$ be an associative ring with identity and $z^*(r)$ be its set of non-zero zero divisors.  the zero-divisor graph of $r$, denoted by $gamma(r)$, is the graph whose vertices are the non-zero  zero-divisors of  $r$, and two distinct vertices $r$ and $s$ are adjacent if and only if $rs=0$ or $sr=0$.  in this paper, we bring some results about undirected zero-divisor graph of a monoid ring ov...

We compared near-infrared observations of the recently discovered outer rings of Uranus with Hubble Space Telescope results. We find that the inner ring, R/2003 U 2, is red, whereas the outer ring, R/2003 U 1, is very blue. Blue is an unusual color for rings; Saturn's enigmatic E ring is the only other known example. By analogy to the E ring, R/2003 U 1 is probably produced by impacts into the ...