The aim of the present study was to evaluate the in vitro antimicrobial activity of pet-ether, dichloromethane and methanol fractions of Swertia chirata (Family: Gentianaceae) ethanolic extract. Disc diffusion technique and food poison method were used for antibacterial and antifungal activity, respectively. Dichloromethane fraction from both leaf and stem showed significant antimicrobial activities against some Gram-positive and Gram-negative bacteria and mild to moderate activity against some fungi. A large zone of inhibition was observed (19 mm) against Staphylococcus aureus. Test materials at a concentration of 400 microg disc(-1) were used to evaluate the antimicrobial activity while Kanamycin at a concentration of 30 microg disc(-1) was used as positive control in this study. Among different fractions, dichloromethane fraction showed significant antimicrobial activity against Gram-positive, Gram-negative and fungi. The most significant antimicrobial activity was seen against Staphylococcus aureus which reflects it potentiality to be used in skin infections.
Zinc oxide (ZnO) thin films were coated onto Indium Tin Oxide (ITO) glass substrate using spin coating technique as a function of annealing temperature. The thin film preparation was undertaken by utilising zinc acetate dihydrate, ethanol and diethanolamine as the precursors. The films were coated at room temperature prior to being annealed at temperatures ranging from 300 °C to 450 °C. The resulting crystalline structure and surface morphology of the thin films were then examined using X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). UV-visible spectrophotometer was also used to record the optical absorbance in wavelengths ranging from 200 to 800 nm. The findings revealed that the ZnO thin films showed a single phase of wurtzite with n-type semiconductor, with the lowest value of band gap energy of 3.28 eV for ZnO thin films annealed at 350 °C. FESEM results showed that the ZnO nanoparticles were very compact on the surface, whereby the average particle size was equivalent to 108.5, 115.3, 108.2 and 107.8 nm at the temperatures 300 °C, 350 °C, 400 °C, and 450 °C, respectively. Additionally, the highest photoconversion efficiency (0.11%) recorded for the sample was annealed at 350◦C. Thus, annealing temperature was found to significantly affect the optical and electrical properties of ZnO nanoparticle seed layer, as well as its band gap energy and surface morphology.
Bamboo has a very rapid growth rate and has been considered a promising non-wood biomass material that has the potential as a feedstock for charcoal production. This study was carried out to elucidate the physico-chemical and energy characteristic of bamboo charcoal produced from two (2) different species which were Aur Kuning Bamboo and Beting Bamboo. Each bamboo was carbonized at a temperature of 300 to 400oC for a duration of two hours. It was found that the density and volatile matter content of bamboo charcoal have decreased, while the ash content, fixed carbon (FC) content and calorific value (CV) have increased after being converted into charcoal. The results show that Aur Kuning Bamboo has good quality bamboo charcoal in comparison with Beting Bamboo in terms of its FC and CV content. Based on the average value, the FC (82.10%) and CV of Aur Kuning Bamboo (27.23%) were higher than FC (70.42%) and CV (26.05%) of Beting Bamboo with 16.59% (FC) and 4.53% (CV) different. Statistical analysis showed that there was a significant effect for different species of bamboo and a significant correlation between physical and energy properties. In conclusion, Aur Kuning Bamboo harvested from Sarawak wild forest has a higher potential to be a feedstock for charcoal production that will be useful for various applications in the near future.
In this study, the co-precipitation approach was used to make nanostructured nickel oxide (NiO) commencing with sodium hydroxide (NaOH) and nickel (II) chloride hexahydrate (NiCl2[Formula: see text]6H2O). Through the use of X-ray diffraction (XRD), scanning electron microscopes (SEM), UV-visible (UV–Vis) absorption, and Fourier transform infrared (FTIR) imaging, structural and optical studies were investigated. FTIR, photoluminescence (PL), cyclic voltammetry (CV) studies are taken. The synthesized nanoparticles were annealed at 300[Formula: see text]C and 400[Formula: see text]C. The face-centered cubic (FCC) structure of the NiO and highly crystallized nanoparticles were revealed by XRD investigations. Observation of FTIR spectra validated the composition of functional groups. Scanning electron microscopy image shows the average size is 24 nm. NiO optical band gap at 300[Formula: see text]C (3.37 eV) and 400[Formula: see text]C (2.7 eV) is revealed from UV studies. From CV graph, the sample annealing at 300[Formula: see text]C and 400[Formula: see text]C the specific capacitance was 543.6 and 519.8 F/g, respectively. This study signifies the supercapacitor application of nanosized metal oxide.
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