GNAnyasor, Ajayi EIO, Saliu JA, Ajagbonna O, Olorunsogo OO. Artesunate opens mitochondrial membrane permeability transition pore. Ann. Trop. Med. Public Health [Internet]. 2009;2(2):39-41. Publisher's VersionAbstract
The incidence of malaria is dramatically increasing, especially because parasites responsible for the majority of fatal malaria infections have now become resistant to commonly used antimalarial drugs such as chloroquine, mefloquine, and quinine. To combat this menace, the World Health Organization (WHO) introduced a new antimalarial drug called artesunate; a hemi-succinate derivative of artemisinin. The in vivo effects of artesunate on rat liver mitochondrial membrane permeability transition (MMPT) pore were investigated in Wister strain albino rats exposed to various doses of artesunate (1.5, 2.0, 3.0 and 5.0 mg per kg body weight per day) for five days. Membrane permeability transition was estimated under energized and de energized spectrophotometric method of Lapidus and Sokolove. The results revealed that artesunate tested at the various doses induced mitochondrial pore opening, induction being minimal (68%) at 5 mg/kg and maximal (240%) at 1.5 mg/kg. In vitro, artesunate at 30, 50 and 70 mg/ml also had an inductive effect in a concentration-dependent manner with minimum induction (18.1%) at 30 mg/ml and maximum induction (32.7%) at 70 mg/ml. Further, preincubation of mitochondria with artesunate for five minutes caused an induction of pore opening in a concentration-dependent manner, with minimum induction (7.9%) at 10 mg/ml and maximum induction (48.6%) at 70 mg/ml. In conclusion, these findings indicate that artesunate could be cytotoxic, opening mitochondrial membrane permeability transition pore, causing the release of cytochrome c and eventually apoptosis.
Alamu OJ, Waheed MA, Jekayinfa SO. Biodiesel production from Nigerian palm kernel oil: effect of KOH concentration on yield. Energy for Sustainable Development (Elsevier). 2007;XI(3):77-82.Abstract
The fears recently expressed by the Energy Commission of Nigeria that the sun will slowly but certainly set on the country’s fossil-fuel-led economy coupled with the worldwide depletion of non- renewable energy sources and its attendant negative environmental impact have resulted in the need to consider alternative renewable fuel sources from the country’s abundant agricultural feedstock. One such crop is oil palm, from which palm kernel oil (PKO) is derived. Transesterification of PKO with ethanol to obtain PKO biodiesel was carried out using potassium hydroxide (KOH) catalyst. ASTM standard fuel tests performed on the PKO biodiesel gave promising results as alternative biodiesel fuel. Concentrations of catalysts have been widely reported as an important process parameter upon which biodiesel yield depends. Further in this work therefore, the effect of KOH concentration on PKO biodiesel yield is studied, with a view to identifying the catalyst concentration corresponding to optimal process yield. Three replicated transesterification experimental runs were carried out for each of the KOH concentrations 0.5 %, 0.75 %, 1.0 %, 1.25 %, 1.5 %, 1.75 % and 2.0 % (by mass of PKO) under identical typical transesterification reaction conditions of 60oC temperature, 120 minutes duration and 20 % ethanol (by mass of PKO). Results of the average PKO biodiesel yield for the respective catalyst concentrations are 90.5 %, 95.0 %, 95.8 %, 85.2 %, 73.3 %, 71.1 % and 71.3 %. The KOH concentration 1.0 % resulting in maximum PKO biodiesel yield (95.8 %) is therefore recommended as optimum, within the constraint of the typical transesterification process parameters used. These findings, agreeing well with earlier works, will find useful applications in the energy sector of the Nigerian economy.
Jekayinfa SO, Alamu OJ, Adigun OJ. Simulation of energy requirement for in-store drying of cereal grains in Nigeria. Journal of Applied Science and Technology, University of Ibadan. 2003;3(1):19-24.Abstract
Meterological data were collected from Ilorin and Ikeja on the monthly mean maximum and minimum dry-bulb temperatures, as well as the average dry-bulb temperature during the coolest 15, 25 and 50 percent of the time, and during the warmest 50 percent of the time.  The absolute humidities of the ambient air during these times were estimated from data collected on relative humidities and dew point.  All these data were further used in calculating the energy requirements for the drying of grain. Also calculated are the power required to pump air through the grain and the periods required for drying. It is found, from a typical case study, that the energy requirement for drying one tonne of grain with moisture content of 22% down to 12.6 percent (wet basis) is 54.0219kWh. The time required by the fan to carry out this drying process is 43.919 hours. The simulated data was compared with an experimental result and there was a reasonable agreement between the two thereby validating the simulation program.