Distribution of polycyclic aromatic hydrocarbons in indoor/outdoor window films and the indoor film/air partition of northeastern Chinese college dormitories.

Indoor window films can represent short-term air pollution conditions of indoor environment through rapidly capturing organic contaminants as effective passive air samplers. To investigate the temporal variation, influence factors of polycyclic aromatic hydrocarbons (PAHs) in indoor window films, and the exchange behavior with gas phase in college dormitories, 42 pairs window films of interior and exterior window surfaces and corresponding indoor gas phase and dust samples were collected monthly in six selected dormitories, Harbin, China, from August to December 2019 and September 2020. The average concentration of ∑16PAHs in indoor window films (398 ng/m2) was significantly (p < 0.01) lower than that in outdoors (652 ng/m2). In addition, the median indoor/outdoor ∑16PAHs concentration ratio was close to 0.5, showing that outdoor air acted as a major PAH source to indoor environment. The 5-ring PAHs were mostly dominant in window films whereas the 3-ring PAHs contributed mostly in gas phase. 3-ring PAHs and 4-ring PAHs were both important contributors for dormitory dust. Window films showed stable temporal variation, i.e. PAH concentrations in heating months were higher than those in non-heating months. The atmospheric O3 concentration was the main influence factor of PAHs in indoor window films. PAHs with low molecular weight in indoor window films rapidly reached film/air equilibrium phase within in dozens of hours. The large deviation in the slope of the log KF-A versus log KOA regression line from that in reported equilibrium formula might be the difference between the window film composition and octanol.

Antibiotic resistance of Helicobacter pylori isolated from children in Chongqing, China.

The resistance of Helicobacter pylori (H. pylori) to antibiotics has been increasing worldwide and varies across different geographic areas and times. Limited studies reported the prevalence of antibiotic resistance and its related gene mutations in children in Chongqing, a city located in southwest China. We collected 112 H. pylori strains isolated from gastric biopsies of 156 children at Children's Hospital of Chongqing Medical University and calculated resistance rates of these strains to six antibiotics. The A2143G and A2142G mutations in 23S rRNA gene, which are related to clarithromycin resistance, and Asn87 and Asp91 mutations in gyrA gene, which are related to levofloxacin resistance, were investigated in 102 strains. The resistance rates to clarithromycin, metronidazole, and levofloxacin were 47.3% (53/112), 88.4% (99/112), and 18.8% (21/112), respectively. No resistance to amoxicillin, tetracycline, and furazolidone was observed. Dual and triple resistance percentages were 37.5% (42/112) and 10.7% (12/112), respectively. The detection rate of A2143G mutation in 23S rRNA gene was 83.3% (40/48). The detection rates of mutations of Asn87 and Asp91 in gyrA gene were 52.6% (10/19) and 36.8% (7/19), respectively. Conclusion: The prevalence of H. pylori resistance to clarithromycin, metronidazole, and levofloxacin was high in children in Chongqing, China. The A2143G mutation was detected in most clarithromycin-resistant strains, and Asn87 and Asp91 of gyrA mutation points were common in levofloxacin-resistant strains. In clinical practice, anti-H. pylori therapy should be individualized based on a susceptibility test.  What is Known: • The resistance of H. pylori to antibiotics changes with the geographic areas and that in Asia the resistance rate is high. • Mutation plays a vital role in antibiotics resistance of H. pylori. What is New: • High resistance rates to single and multiple antibiotics in children of Chongqing, a city located in southwest China, were observed. • Molecular assays showed good conformance with susceptibility test results to direct antibiotic resistance of H. pylori.

[Chemical constituents from the root of Ilex cornuta].

OBJECTIVE: To investigate the chemical constituents of the root of Ilex cornuta. METHODS: The constituents were isolated by silica gel, Sephadex LH-20 gel, medium pressure column and semi-preparative liquid chromatography and their structures were elucidated by chemical properties and spectroscopic analyses. RESULTS: Ten compounds were isolated and their structures were identified as: Oleanolic acid (1), Siaresinolic acid (2), 28-O-beta-D-glucopyranosyl pomolic acid (3), Pomolic acid (4), 3beta-O-alpha-L-arabinopyranosyl rotundic acid (5), 3beta-[alpha-L-arabinopyranosyl) oxy]-19alpha-hydroxyolean-12-en-28-oic acid 28-beta-D-glucopyranosyl ester (6), Lup-20(29)-en-3beta,23-diol (7), Chikusetsusaponin IV a butyl ester (8), Oleanolic acid-3-O-( 6'-O-methyl)-beta-D-glucuronopyranoside (9), 3-O-[(alpha-L-arabinopyranosyl)-(1 --> 2)]-beta-D-glucuronopyranosyl-(6'-O-methyl-ester)-olean-12-ene-28-olic acid (10). CONCLUSION: Compounds 7 - 10 are isolated from this genus for the first time, and compounds 2 - 6 are isolated from this plant for the first time.