Study on the Adsorption and Reactions of FCH₂CH₂OH and ClCH₂CH₂OH on Ni(111): Effects of Halogen and Preadsorbed Oxygen

Temperature-programmed reaction/desorption (TPR/D), reflection–absorption infrared spectroscopy (RAIRS), and X-ray photoelectron spectroscopy (XPS) have been employed to investigate the reactions of FCH₂CH₂OH and ClCH₂CH₂OH on Ni(111) and oxygen-precovered Ni(111) (O/Ni(111)). In the chemical process of FCH₂CH₂OH on Ni(111), only FCH₂CH₂O- is found to be the stable reaction intermediate, which starts to appear at ∼190 K. At low coverages, this intermediate decomposes into H₂ and CO. Additional C₂H₄ (219 K) is generated at higher exposures. On Ni(111) at 200 K, ClCH₂CH₂OH mainly dissociates to form ClCH₂CH₂O- and -CH₂CH₂O- at lower exposures, with H₂ and CO as the final products, while ClCH₂CH₂O- becomes predominant at higher exposures and is responsible for the extra C₂H₄ channel of 218 K. C₂H₄ is also generated at 161 and 174 K as the exposure is increased to render multilayer adsorption. Due to the competition in the scission of the carbon–halogen and carbon–hydrogen bonds, ClCH₂CH₂OH has better reactivity toward C₂H₄ formation than FCH₂CH₂OH. No -CH₂CH₂OH is found in the decomposition of FCH₂CH₂OH and ClCH₂CH₂OH on Ni(111), which is the intermediate in the reaction of ICH₂CH₂OH on Ni(100) and Pd(111). The presence of preadsorbed oxygen can enhance the ethylene formation at low coverages of FCH₂CH₂OH and ClCH₂CH₂OH. At higher coverages, additional acetaldehyde is formed in the reaction of FCH₂CH₂OH, in contrast to the ethylene oxide from ClCH₂CH₂OH

Study on the Adsorption and Reactions of FCH₂CH₂OH and ClCH₂CH₂OH on Ni(111): Effects of Halogen and Preadsorbed Oxygen

Temperature-programmed reaction/desorption (TPR/D), reflection–absorption infrared spectroscopy (RAIRS), and X-ray photoelectron spectroscopy (XPS) have been employed to investigate the reactions of FCH₂CH₂OH and ClCH₂CH₂OH on Ni(111) and oxygen-precovered Ni(111) (O/Ni(111)). In the chemical process of FCH₂CH₂OH on Ni(111), only FCH₂CH₂O- is found to be the stable reaction intermediate, which starts to appear at ∼190 K. At low coverages, this intermediate decomposes into H₂ and CO. Additional C₂H₄ (219 K) is generated at higher exposures. On Ni(111) at 200 K, ClCH₂CH₂OH mainly dissociates to form ClCH₂CH₂O- and -CH₂CH₂O- at lower exposures, with H₂ and CO as the final products, while ClCH₂CH₂O- becomes predominant at higher exposures and is responsible for the extra C₂H₄ channel of 218 K. C₂H₄ is also generated at 161 and 174 K as the exposure is increased to render multilayer adsorption. Due to the competition in the scission of the carbon–halogen and carbon–hydrogen bonds, ClCH₂CH₂OH has better reactivity toward C₂H₄ formation than FCH₂CH₂OH. No -CH₂CH₂OH is found in the decomposition of FCH₂CH₂OH and ClCH₂CH₂OH on Ni(111), which is the intermediate in the reaction of ICH₂CH₂OH on Ni(100) and Pd(111). The presence of preadsorbed oxygen can enhance the ethylene formation at low coverages of FCH₂CH₂OH and ClCH₂CH₂OH. At higher coverages, additional acetaldehyde is formed in the reaction of FCH₂CH₂OH, in contrast to the ethylene oxide from ClCH₂CH₂OH

Chromosome-Borne CTX-M-65 Extended-Spectrum β-Lactamase–Producing Salmonella enterica Serovar Infantis, Taiwan

A CTX-M-65‒producing Salmonella enterica serovar Infantis clone, probably originating in Latin America and initially reported in the United States, has emerged in Taiwan. Chicken meat is the most likely primary carrier. Four of the 9 drug resistance genes have integrated into the chromosome: blaCTX-M-65, tet(A), sul1, and aadA1

Epidemiological trends and antimicrobial resistance in Salmonella enterica serovar Typhimurium clones in Taiwan between 2004 and 2019

ABSTRACT: Objectives: We investigated the temporal trends of Salmonella enterica serovar Typhimurium (S. Typhimurium) clones in Taiwan from 2004 to 2019, focusing on antimicrobial resistance (AMR), resistance genetic determinants, and plasmid types. Methods: Salmonella isolates were characterized using pulsed-field gel electrophoresis (PFGE), whole-genome sequencing, and antimicrobial susceptibility testing. Clones were defined using PFGE clustering and the hierarchical cgMLST clustering (HierCC) assignments. Results: Seven major S. Typhimurium clones, HC100_2, 13, 41, 305, 310, 501, and 46261, accounted for 97.6% (8079/8275) of human isolates in Taiwan. Each clone displayed a unique AMR profile, resistance genetic determinants, and plasmid types. Four highly resistant clones (HC100_2, 41, 305, and 310) exhibited multiple resistance in 86.5% to 96.1% of isolates. HC100_305 and HC100_2 were pandemic multidrug-resistant clones, characterized by resistance to ampicillin, chloramphenicol, streptomycin, sulfonamides, and tetracycline (ACSSuT) and ASSuT, respectively. The prevalence of the ACSSuT clone decreased from 68.7% of S. Typhimurium isolates in 2004 to 1.7% in 2019, while the ASSuT clone emerged in 2007 and became the largest clone after 2010. Several plasmids, including IncHI2-IncHI2A, IncC, IncFIB(K), and IncI1–1(α), carried multiple resistance genes or were associated with the carriage of mph(A), blaCMY-2, and blaDHA-1. Conclusions: Between 2004 and 2019, Taiwan experienced the emergence, prevalence, and subsequent decline of several highly resistant S. Typhimurium clones. The clones defined using the HierCC approach have global comparability. The increasing resistance to third-generation cephalosporins, cephamycins, ciprofloxacin, and azithromycin in recent years poses a significant medical concern