Efficacy of inactivation of human enteroviruses by dual-wavelength germicidal ultraviolet (UV-C) light emitting diodes (LEDs)

The efficacy of germicidal ultraviolet (UV-C) light emitting diodes (LEDs) was evaluated for inactivating human enteroviruses included on the United States Environmental Protection Agency (EPA)'s Contaminant Candidate List (CCL). A UV-C LED device, emitting at peaks of 260 nm and 280 nm and the combination of 260∣280 nm together, was used to measure and compare potential synergistic effects of dual wavelengths for disinfecting viral organisms. The 260 nm LED proved to be the most effective at inactivating the CCL enteroviruses tested. To obtain 2-log₁₀ inactivation credit for the 260 nm LED, the fluences (UV doses) required are approximately 8 mJ/cm² for coxsackievirus A10 and poliovirus 1, 10 mJ/cm² for enterovirus 70, and 13 mJ/cm² for echovirus 30. No synergistic effect was detected when evaluating the log inactivation of enteroviruses irradiated by the dual-wavelength UV-C LEDs.

Effects of Telfairia Occidentalis Leaf Extract on Plasma Lactate and Liver Glycogen in Rats

Telfairia occidentalis is a green vegetable popularly consumed among the native of Africa and it is generallybelieved to be of medicinal and nutritional value. Studies have reported its hypoglycaemic and hyperglycaemic effects inrats. In addition to these conflicting reports, the mechanisms for its effects on blood glucose remain inconclusive. Theobjective of this study was to investigate the mechanism involved in the increased blood glucose following treatment withT. occidentalis. Twenty five (25) male albino rats (200-250g) were randomly divided into 5 groups (n=5/group). Rats in thecontrol group received normal saline while rats in other groups were orally treated with 100 or 200 mg/kg body weight ofthe extract for either 1 or 2 weeks. At the end of the treatment, the rats were anaesthetized and blood samples were collectedfor the estimation of some biochemical parameters. The results showed significant decreases in plasma glucose after 1 weekof treatment with 100 mg/kg and 200 mg/kg. However, after 2 weeks of treatment with both doses, plasma glucose levelsincreased significantly and were higher than those of the control and the rats treated for 1 week with both doses. There werealso dose- and duration-dependent decreases in glycogen concentration in the treated rats, especially those treated for twoweeks. Glucose-6-phosphatase activity and liver glycogen concentration were lower in rats treated for 2 weeks whencompared with those treated for 1 week with both doses. Moreover, plasma lactate concentration was lower in the treatedgroups when compared with control. The results suggest that Telfairia occidentalis-induced lowering of plasma glucose afterone week of treatment probably favoured lactate oxidation/gluconeogenesis and elicited breakdown of liver glycogen whichresulted in increased plasma glucose after two weeks of treatment.

Evaluating UV-C LED disinfection performance and investigating potential dual-wavelength synergy

A dual-wavelength UV-C LED unit, emitting at peaks of 260 nm, 280 nm, and the combination of 260|280 nm together was evaluated for its inactivation efficacy and energy efficiency at disinfecting Escherichia coli, MS2 coliphage, human adenovirus type 2 (HAdV2), and Bacillus pumilus spores, compared to conventional low-pressure and medium-pressure UV mercury vapor lamps. The dual-wavelength unit was also used to measure potential synergistic effects of multiple wavelengths on bacterial and viral inactivation and DNA and RNA damage. All five UV sources demonstrated similar inactivation of E. coli. For MS2, the 260 nm LED was most effective. For HAdV2 and B. pumilus, the MP UV lamp was most effective. When measuring electrical energy per order of reduction, the LP UV lamp was most efficient for inactivating E. coli and MS2; the LP UV and MP UV mercury lamps were equally efficient for HAdV2 and B. pumilus spores. Among the UV-C LEDs, there was no statistical difference in electrical efficiency for inactivating MS2, HAdV2, and B. pumilus spores. The 260 nm and 260|280 nm LEDs had a statistical energy advantage for E. coli inactivation. For UV-C LEDs to match the electrical efficiency per order of log reduction of conventional LP UV sources, they must reach efficiencies of 25-39% or be improved on by smart reactor design. No dual wavelength synergies were detected for bacterial and viral inactivation nor for DNA and RNA damage.