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The occurrence of heavy metal ions in food chain is appearing to be a major problem for mankind. The traces of heavy metals, especially Pb(II) ions present in water bodies remains undetected, untreated, and it remains in the food cycle causing serious health hazards for human and livestock. The consumption of Pb(II) ions may lead to serious medical complications including multiple organ failure which can be fatal. The conventional methods of heavy metal detection are costly, time-consuming and require laboratory space. There is an immediate need to develop a cost-effective and portable sensing system which can easily be used by the common man without any technical knowhow. A portable resistive device with miniaturized electronics is developed with microfluidic well and α-MnO 2 /GQD nanocomposites as a sensing material for the sensitive detection of Pb(II). α-MnO 2 /GQD nanocomposites which can be easily integrated with the miniaturized electronics for realtime on-field applications. The proposed sensor exhibited a tremendous potential to be integrated with conventional water purification appliances (household and commercial) to give an indication of safety index for the drinking water. The developed portable sensor required low sample volume (200 µL) and was assessed within the Pb(II) concentration range of 0.001 nM to 1 uM. The Limit of Detection (LoD) and sensitivity was calculated to be 0.81 nM and 1.05 kΩ/nM/mm 2 , and was validated with the commercial impedance analyser. The shelf-life of the portable sensor was found to be ∼45 days.This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Lead (Pb) ions are a major concern to the environment and human health as they are contemplated cumulative poisons. In this study, facile synthesis of magnetic iron oxide-tea waste nanocomposite is reported for adsorptive removal of lead ions from aqueous solutions and easy magnetic separation of the adsorbent afterwards. The samples were characterised by scanning electron microscopy, Fourier transform-infrared spectroscopy, X-ray diffraction, and Braunner-Emmet-Teller nitrogen adsorption study. Adsorptive removal of Pb(II) ions from aqueous solution was followed by ultraviolet-visible (UV-Vis) spectrophotometry. About 95% Pb(II) ion removal is achieved with the magnetic tea waste within 10 min. A coefficient of regression R 2 ≃ 0.99 and adsorption density of 18.83 mg g −1 was found when Pb(II) ions were removed from aqueous solution using magnetic tea waste. The removal of Pb(II) ions follows the pseudo-second-order rate kinetics. External mass transfer principally regulates the rate-limiting phenomena of adsorption of Pb(II) ions on iron oxide-tea waste surface. The results strongly imply that magnetic tea waste has promising potential as an economic and excellent adsorbent for the removal of Pb(II) from water.

Up to a third of ex-preterm infants flying near term exhibit pulse oxygen saturation (SpO 2 ) of less than 85% during air travel. A hypoxia challenge test (HCT) is recommended to evaluate the requirement for in-flight supplemental O 2 . The validity of the HCT in healthy, term infants has not been reported. This study aimed to characterise the in-flight hypoxia response and the accuracy of the HCT to predict this response in healthy, term infants in the first year of life. Infants (n=24: (15 male)) underwent a HCT prior to commercial air travel during which parents monitored SpO 2 . Thirty-two flights were undertaken with six infants completing multiple flights. The median in-flight SpO 2 nadir was 87% and significantly lower than the HCT SpO 2 nadir (92%: p<0.001). Infants on seven flights recorded SpO 2 <85% with one infant recording a HCT with a SpO 2 less than 85%. There was marked variability in the inflight SpO 2 in the six infants who undertook multiple flights, and for three of these infants, the SpO 2 nadir was both above and below 85%. We report that in healthy term infants an in-flight SpO 2 below 85% is common and can vary considerably between flights and that the HCT poorly predicts the risk of in-flight hypoxia (SpO 2 <85%). As it is common for healthy term infants to have SpO 2 less than 85% during air travel further research is needed to clarify whether this is an appropriate cut-off in this age group.Commercial aircrafts are pressurised to a maximum altitude of 2400 m during air travel resulting in a partial oxygen (O 2 ) pressure equivalent to 15-17% compared with 21% at sea level.1 In healthy children and adults pulse oxygen saturation (SpO 2 ) declines to 89-94% during flight.2 There are only limited reports of the in-flight hypoxia response in healthy infants.The hypoxia challenge test (HCT) is used to evaluate the requirement for in-flight supplemental O 2 and involves monitoring SpO 2 while inhaling a fractional inspired O 2 concentration of ∼15%.1 Preterm infants less than 1 year should use in-flight supplemental O 2 if the SpO 2 decreases to <85% during the HCT. 1 We have reported that preterm neonates flying near term exhibit hypoxia and that the HCT is unreliable.3 The validity of the HCT in older infants has not been reported. This study aimed to characterise the in-flight hypoxia response and the accuracy of the HCT in healthy infants in the first year of life.We recruited 24 healthy term infants (15 male) aged 2.3-44.6 weeks. Infants underwent a HCT 3 4 prior to commercial air travel. Parents monitored in-flight SpO 2 (WristOx 3100; Nonin, Minnesota, USA) and activity state. Ethical approval was received (Princess Margaret Hospital for Children Ethics Committee: 1533/EP) and written consent obtained.Thirty-two flights were undertaken with six infants completing multiple flights. Activity was recorded in 26 (81%) flights with 14 infants being asleep and the remainder being awake with no differences in the in-flight SpO 2 nadir in sleeping infants compared with awake infants (...