Phytochemical s creening and a ntibacterial a ctivities of Tectona grandis L. f. (Teak) l eaves on m icroorganisms i solated from d ecayed f ood s amples

Bacteria were isolated from decayed food samples (tomatoes, cooked beans and rice) collected from Afe Babalola University, Ado Ekiti (ABUAD) cafeteria and characterized. Some of these isolated microorganisms could pose serious har m to humans including animals and they are normally treated with commercial antibiotics. However, the majority of bacteria are resistant to many antibiotics therefore, the use of plant extracts with therapeutic potential against resistant bacteria is neces sary. In this investigation, eight bacteria were isolated from decayed food samples. The bacterial isolates were identified as Bacillus cereus and B. siamensis from rice sample; Klebsiella oxytoxa , Salimicrobium halophilium and Norcardia brasiliensis from beans sample; Bacillus subtilis , Enterobacter taylore , and Brevibacillus agri from tomatoes. The leaf samples of Tectona grandis were screened qualitatively and quantitatively for the phytochemicals while the crude methanol and chloroform extracts were used as antimicrobial agents against the isolated microorganisms. Alkaloids, carotenoids and tannins were present in large amount. T he bacterial isolates were more susceptible to commercial antibiotics than that of methanol extracts of T. grandis . The methanol extracts of T. grandis have a higher antimicrobial activity than the chloroform ext ract

Fundamental design strategies for advancing the development of high entropy alloys for thermo-mechanical application: A critical review

Nearly three decades since the discovery of high entropy alloys (HEAs), it has greeted a broad interest in the field of materials research as a better alternative to conventional alloy materials due to the exceptional combinatorial properties they offer in terms of lightweight, high-specific strength in elevated temperatures, excellent oxidation and corrosion resistance properties (among others). Leveraging on the “four core effects”: high-entropy effect, sluggish/hysteretic diffusion effect, severe-lattice-distortion effect and cocktail effect which define the special features responsible for their outstanding properties, HEAs have been successfully employed for high-temperature applications in automobile and in the aerospace. An emerging sub-field of HEAs is the incorporation of a secondary strengthening phase that can be provided by the precipitation of intermetallic (IM) compounds to enhance the microstructure which will concomitantly affect the properties of a material (thermal, chemical and mechanical properties) for broader engineering applications. In this article, design concepts brewed from thermo-physical parameters calculation and computational thermodynamics using a CALPHAD-based tool were reviewed as fundamental design strategies in the development of IM-containing HEAs