RESUMEN
Harnessing the key intermediates in metal-catalyzed reactions is one of the most essential strategies in the development of selective organic transformations. The nitrogen group transfer reactivity of metal-nitrenoids to ubiquitous C-H bonds allows for diverse C-N bond formation to furnish synthetically valuable aminated products. In this study, we present an unprecedented reactivity of iridium and ruthenium nitrenoids to generate remote carbocation intermediates, which subsequently undergo nucleophile incorporation, thus developing a formal γ-C-H functionalization of carboxylic acids. Mechanistic investigations elucidated a unique singlet metal-nitrenoid reactivity to initiate an abstraction of γ-hydride to form the carbocation intermediate that eventually reacts with a broad range of carbon, nitrogen, and oxygen nucleophiles, as well as biorelevant molecules. Alternatively, the same intermediate can lead to deprotonation to afford ß,γ-unsaturated amides in a less nucleophilic solvent.
RESUMEN
The latest advances in mobile platforms, such as robots, have enabled the automatic acquisition of full coverage point cloud data from large areas with terrestrial laser scanning. Despite this progress, the crucial post-processing step of registration, which aligns raw point cloud data from separate local coordinate systems into a unified coordinate system, still relies on manual intervention. To address this practical issue, this study presents an automated point cloud registration approach optimized for a stop-and-go scanning system based on a quadruped walking robot. The proposed approach comprises three main phases: perpendicular constrained wall-plane extraction; coarse registration with plane matching using point-to-point displacement calculation; and fine registration with horizontality constrained iterative closest point (ICP). Experimental results indicate that the proposed method successfully achieved automated registration with an accuracy of 0.044 m and a successful scan rate (SSR) of 100% within a time frame of 424.2 s with 18 sets of scan data acquired from the stop-and-go scanning system in a real-world indoor environment. Furthermore, it surpasses conventional approaches, ensuring reliable registration for point cloud pairs with low overlap in specific indoor environmental conditions.
RESUMEN
The profile of virulence genes and repetitive element sequence-based PCR (rep-PCR) genomic fingerprinting were determined on Escherichia coli strains isolated from patients with urinary tract infection to investigate genetic relatedness and its identification. Thirty nine strains of E. coli were examined genotypically by using the multiplex polymerase chain reaction for the presence of five urovirulence genes; pyelonephritis-associated pili (pap), S. fimbriae (sfa), afimbrial adhesin (afa), cytotoxic necrotizing factor (cnf ), and a-hemolysin (hly). As a result, genotype pap+sfa-afa-cnf -hly- was the most dominant (14 strains: 36%). But no urovirulence-genes were detected in 12 strains (31%). On the basis of rep-PCR, the dendrograms generated from REP-PCR and ERIC-PCR revealed that uropathogenic E. coli strains were clustered into non-uropathogenic E. coli ATCC 43894 O157:H7 with the degree of similarity 37% and 44%, respectively. On the contrary, BOX-PCR results showed that uropathogenic E. coli strains differed from non-uropathogenic E. coli ATCC 43894 O157:H7 with the degree of similarity 37%. According to these findings, REP-PCR and ERIC-PCR were unable to discriminate reliably uropathogenic E. coli from non-uropathogenic E. coli. However, BOX-PCR provided an effective mean of differentiating E. coli strains between uropathogenic and non-uropathogenic.