Background: There is a renewed global interest in plant-based medicine in the last few decades as a result of affordability and efficacy of the form of medicine. However, the safety of many medicinal plants and plant preparations has not been determined. To this end, this study determined the safety of the methanol extracts of the leaves of Guiera senegalensis, Cassia occidentalis, and Ziziphus mauritiana, which are plants commonly used in plant medicine in Africa. Results: Phytochemistry of the plants' extracts showed alkaloids were the most abundant phytochemical in the extracts, followed by tannins, saponins, flavonoids, and glycosides, respectively. All the rats behaved normally at doses up to 2000 mg kg −1 , while at 3000 mg kg −1 , rats in C. occidentalis group developed breathing problems. At 5000 mg kg −1 , C. occidentalis group showed convulsion, whereas Z. mauritiana and G. senegalensis rats displayed temporary weakness. After 60-day dosing, significant differences (p < 0.05) were observed in the liver enzymes (ALP, AST, ALT, TP, and ALB) of most of the test rats compared with the control. Kidney function test showed the Na + , K + , Cl − , urea, and creatinine of the test rats were reduced compared with the control, but only significant (p < 0.05) in a few of the parameters. Fatty metamorphosis, lymphocytic infiltration, and karyorrhexis were observed in the liver tissues of the treated rats, but not in the control. Conclusion: These results show the plants are nontoxic at moderate doses, but could be injurious at high doses or if taken repeatedly for an extended period.
A new circuit topology is designed for a DC-DC converter. The proposed converter employs a single power switch which integrates a conventional boost with a single-ended primary inductor converter (SEPIC) for photovoltaic (PV) panels. A prototype is developed and implemented for 105 V DC output from 9 V DC input. The performance of the proposed topology was validated using theoretical and practical verification. The results indicated a higher voltage gain of 11.67, low duty-cycle of 0.82 and reduced voltage stress across the components of about 54 V. The circuit can be used for PV panels and other renewable energy resources that require a DC-DC voltage step-up conversion ratio.
Environmental natural background ionizing radiation contamination and degradation is a global concern because of its negative effect on public health. Public health risk continues to be one of the environmental and public concerns in Nigeria. The emission of natural background ionizing radiation from the outer space, crust of the earth, food, and water and construction materials contributed a lot to the public environmental exposure. The populations’ exposure to background radiation emanated from terrestrial, cosmic, and internal radiation account for 82% which are out of control. Present work was aimed to carry out an investigational study of the natural background ionizing radiation levels, identify locations with high or low BIR and assess the health effect within Nigeria’s communities based on the available data extracted from the literatures and establish a baseline data of exposure rate, absorbed dose rate, annual effective dose equivalent, and excess life cancer risk from outdoor and indoor background radiation. This dosimetric study of natural background radiation in Nigeria is important to monitor the levels of radiation to which people are exposed directly or indirectly. Recently, several studies have been done in Nigeria and different values were reported based on indoor and outdoor background radiation doses. In this paper, a review and literature survey of natural background ionizing radiation was carried out. The data extracted based on indoor and outdoor revealed that Plateau, Oyo, River, Delta and Ondo, Sokoto, Kano and Niger have the highest value of dose rate compared to the world average value. The order of magnitude of the dose rate were Plateau > Oyo > Rive > Delta > Ondo and River > Plateau > Sokoto > Kano > Oyo > Ondo > Delta > Niger for Indoor and outdoor respectively. The highest outdoor & indoor annual effective doses were observed in OYO, Sokoto, Ondo, Delta, Akwanga, Plateau, and River. The results were comparatively greater than the world acceptable limit of 1.0 mSv/y. The order of magnitude of annual effective are OYO > Sokoto > Ondo > Niger Delta and Akwanga > Plateau > Delta > River for outdoor and indoor respectively. The regions with highest excess life cancer risks in Nigeria were observed in Oyo, Akwanga, Ondo, Plateau, River, Kaduna, Anambra, Port court, Abuja, Delta, Ibadan and Kano. Radiation cancer induction values obtained were remarkably high compared to world average value of 0.29×10-3. The amount of radiation absorbed by individual organs exposed to high natural background radiation areas were observed to be highest in tests organ, the order of magnitude were Tests > Bone marrow > Whole body > Lung > Ovaries > Kidney > Liver. But all the estimated mean values of organs doses were remarkably lower than that of world average value. Since the mean absorbed dose rate and annual effective dose in several areas is higher than 0.084µSv/h and 1.0 mSv/year for general public in many locations, long term exposure of the public to these radiations may lead to radiation induced health hazard such as erythema, skin cancer, genetic mutation and sterility.
Background The demands for clean energy is growing rapidly and the fossil fuel we use in our everyday live is ushered in CO2 and other greenhouse effects, resulting in natural disasters and other climate threats. To continue on this route, the world is challenged to prepare for the unknown disasters. Hence, the search for a clean, alternative energy resource, which could bring resilience back to our cities is in incredibly rapid velocity. Solar energy is a clean and alternative energy that can be use but PV panels tend to generate low energy in nature which is why a lot of panels have to be employed in order to go off-grid. A simple DC-DC converter can be used to boost the energy generated by PV panels. Provided herein is an extended DC-DC single ended primary inductor converter (SEPIC) for micro-grid based photovoltaic (PV) applications. The new topology was designed with an addition of some components to the conventional SEPIC. Results The extended SEPIC topology utilizes a single power switch with high voltage gain, low duty-cycle, reduced voltage stress across the power switch, low density and cheap. The new topology was designed with an addition of some components to the conventional SEPIC. A 125 V DC output was generated from a 12 V DC input through MATLAB/SIMULINK. The new SEPIC converter revealed the best value voltage gain as 10.42, duty-cycle value of 0.8 and voltage stress of 62.5 V compared to the conventional SEPIC or SEPIC integrated with other converters. Conclusions the results of voltage gain, duty-cycle and voltage stress obtained validate the credibility of the new converter and show the potentiality of the converter for the adoption in power step-up applications.
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