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SettingThe impact of the genetic characteristics of Mycobacterium tuberculosis on the clustering of multidrug-resistant tuberculosis (MDR-TB) has not been analyzed together with clinical and demographic characteristics.ObjectiveTo determine factors associated with genotypic clustering of MDR-TB in a community-based study.DesignWe measured the proportion of clustered cases among MDR-TB patients and determined the impact of clinical and demographic characteristics and that of three M. tuberculosis genetic characteristics: lineage, drug resistance-associated mutations, and rpoA and rpoC compensatory mutations.ResultsOf 174 patients from California and Texas included in the study, the number infected by East-Asian, Euro-American, Indo-Oceanic and East-African-Indian M. tuberculosis lineages were respectively 70 (40.2%), 69 (39.7%), 33 (19.0%) and 2 (1.1%). The most common mutations associated with isoniazid and rifampin resistance were respectively katG S315T and rpoB S531L. Potential compensatory mutations in rpoA and rpoC were found in 35 isolates (20.1%). Hispanic ethnicity (OR 26.50, 95%CI 3.73-386.80), infection with an East-Asian M. tuberculosis lineage (OR 30.00, 95%CI 4.20-462.40) and rpoB mutation S531L (OR 4.03, 95%CI 1.05-23.10) were independent factors associated with genotypic clustering.ConclusionAmong the bacterial factors studied, East-Asian lineage and rpoB S531L mutation were independently associated with genotypic clustering, suggesting that bacterial factors have an impact on the ability of M. tuberculosis to cause secondary cases.

Antioxidant compounds and their antioxidant activity in 4 different colored (green, yellow, orange, and red) sweet bell peppers (Capsicum annuum L.) are examined. All 4 colored peppers showed substantial abilities in preventing the oxidation of cholesterol or docosahexaenoic acid (DHA) (C22:6) during heating, but they did not shown any difference in their abilities in preventing cholesterol oxidation.

The reactivity of W(NPh)(o-Me(sub 3)SiN)(sub 2)C(sub 6)H(sub 4)(pyridine)(sub 2) and W(NPh)(o-Me(sub 3)SiN)(sub 2)C(sub 6)H(sub 4)(picoline)(sub 2) with unsaturated substrate is investigated. The addition of some aldehyde, net substrate insertion into the ortho C-H bond of pyridine to form tungsten azaoxymetallacycle complexes is observed with both alphatic and aromatic aldehyde participating in the reaction.

The pursuit of a cost-effective and green synthetic approach to chemical sensors and their application in the sensing of toxic and harmful substances is a never-ending exercise for scientists and researchers. Preparation of fluorescent carbon dots (C-dots) from biomass using water as a solvent and a hydrothermal autoclave to provide the required synthesis temperature offers a cheap and environmentally friendly synthetic approach. Herein, we report a faster, less costly and ecofriendly hydrothermal synthetic approach of carbon dots from Citrullus vulgaris peels as a precursor. The as-prepared carbon dots exhibited hydroxyl, carbonyl and amide functional groups on the surface and an amorphous structure with a particle size distribution of 1.7–3.0 nm. Moreover, the carbon dots displayed intense blue emission fluorescence at 470 nm after excitation at 400 nm. The as-prepared carbon dots demonstrated effective application without further modification towards the selective and sensitive optical recognition of 2-nitrophenol used in the manufacture of explosives. A limit of detection of 2.28×10−7 M was achieved, and no fluorescence quenching was observed in the presence of other nitroaromatic and benzene derivatives indicating excellent selectivity towards 2-nitrophenol. Finally, further studies are required to investigate the potential for the as-prepared carbon dots to monitor nitroaromatic pollutants in real environmental systems. Significance: • Terrorism is an ever-increasing problem, and law enforcement agencies are continuously searching for and detecting explosives hidden in travel luggage, mail packages, vehicles and aircrafts using sophisticated equipment which are not available in developing countries such as Botswana. • This work unveils a facile and environmentally friendly approach towards the detection of 2-nitrophenol used in the manufacture of explosives by employing highly luminescent C-dots obtained from locally available agricultural waste. • The utilisation of agricultural waste can help advance a sustainable waste management programme and promote a circular economy.