Compatibility and complementarity of indigenous and scientific knowledge of wild plants in the highlands of southwest Saudi Arabia

This study presents a survey of wild plants commonly used by local inhabitants in the highlands of southwest Saudi Arabia. Based upon literature review, direct observation of local inhabitants, and questionnaire interviews, 36 plant species were assessed and given scores according to their use. The gaps between scientific and indigenous knowl- edge on the use of plants were estimated using a ＂compatibility ratio＂. The score values were estimated based on seven different use categories of ecosystem services, including food, forage, medicine, wood, beekeeping, research, and education. Additional structural categories include source of materials, shade, hedges, ornamental plantings, and soil stabilization. There are discrepancies between indigenous knowledge （IK） and scien- tific knowledge （SK） but in most cases, SK of the species supports the IK and plant users preference. The results also provide information that challenges assumptions about the consistency of IK with SK. Our study highlights the importance of understanding the cultural context and uses of wild plants. Biodiversity-based knowledge holds promise for contributing to sustainable use of wild plant resources and related traditions. The success of such endeavours depends on the compatibility and complementarity of indigenous and scientific knowledge.

Sensitive and fast response ethanol chemical sensor based on as-grown Gd_2O_3 nanostructures

Well crystalline gadolinium oxide（Gd2O3） nanostructures were grown by annealing the hydrothermally as-prepared nanostructures without using any template. Microscopic studies of Gd2O3 nanostructures were recorded along the [111] direction due to the clearly resolved interplanar distance d（222）-0.31 nm of the cubic crystal structure Gd2O3. Sensing mechanism of Gd2O3 as efficient electron mediator for the detection of ethanol was explored. As-fabricated sensor demonstrated the high-sensitivity of -0.266 μAm/M/cm2 with low detection limit（-52.2 μmol/L） and correlation coefficient（r^2, 0.618）. To the best of our knowledge, this was the first report for the detection of ethanol using as-grown（at 1000 oC） Gd2O3 nanostructures by simple and reliable Ⅰ-Ⅴ technique and rapid assessment of the reaction kinetics（in the order of seconds）. The low cost of the starting reagents and the simplicity of the synthetic route made it a promising chemical sensor for the detection of various toxic analytes, which are not environmentally safe.

Mesoporous WO_3-graphene photocatalyst for photocatalytic degradation of Methylene Blue dye under visible light illumination

Advanced oxidation technologies are a friendly environmental approach for the remediation of industrial wastewaters. Here, one pot synthesis of mesoporous WO3 and WO3-graphene oxide（GO） nanocomposites has been performed through the sol–gel method. Then, platinum（Pt） nanoparticles were deposited onto the WO3 and WO3-GO nanocomposite through photochemical reduction to produce mesoporous Pt/WO3 and Pt/WO3-GO nanocomposites. X-ray diffraction（XRD） findings exhibit a formation of monoclinic and triclinic WO3 phases. Transmission Electron Microscope（TEM） images of Pt/WO3-GO nanocomposites exhibited that WO3 nanoparticles are obviously agglomerated and the particle sizes of Pt and WO3 are ~ 10 nm and 20–50 nm, respectively. The mesoporous Pt/WO3 and Pt/WO3-GO nanocomposites were assessed for photocatalytic degradation of Methylene Blue（MB） as a probe molecule under visible light illumination.The findings showed that mesoporous Pt/WO3, WO3-GO and Pt/WO3-GO nanocomposites exhibited much higher photocatalytic efficiencies than the pure WO3. The photodegradation rates by mesoporous Pt/WO3-GO nanocomposites are 3, 2 and 1.15 times greater than those by mesoporous WO3, WO3-GO, and Pt/WO3, respectively. The key factors of the enhanced photocatalytic performance of Pt/WO3-GO nanocomposites could be explained by the highly freedom electron transfer through the synergetic effect between WO3 and GO sheets, in addition to the Pt nanoparticles that act as active sites for O2 reduction, which suppresses the electron hole pair recombination in the Pt/WO3-GO nanocomposites.