Tailoring local coordination structure of the Er ions for tuning the up-conversion multicolor luminescence.

The regulation of the local structure around Er ions is an important channel for adjusting the characteristic of up-conversion luminescence. In this paper, the cubic-phased Er:CaF crystals with different Er doping concentrations were fabricated with temperature gradient technique (TGT) method and the effect of the local coordination structure of the Er ions on its luminescence performance was investigated. The local coordination structure of Er ions was simulated by density functional theory.

Antibiotic resistance monitoring in heterotrophic bacteria from anthropogenic-polluted seawater and the intestines of oyster Crassostrea hongkongensis.

A total of 1,050 strains of heterotrophic bacteria isolated from farming seawater and the intestines of oyster species Crassostrea hongkongensis were tested for resistance to 10 antibiotics by the Kirby-Bauer diffusion method. The resistant rates of seawater-derived bacteria to chloramphenicol, enrofloxacin, and ciprofloxacin were low (less than 20%), whereas the bacteria obtained from oysters showed low resistance to chloramphenicol and enrofloxacin. Many strains showed high resistant rates (more than 40%) to furazolidone, penicillin G, and rifampin.