Aim: Investigate the possible mechanism (s) of the poor bioavailability of a lipophilic compound in rats using the physiologically based pharmacokinetic (PBPK) modeling approach. Methodology: A rat PBPK model was constructed using data from intravenous administration, and verified by comparing predicted tissue concentrations (kidneys, liver and lungs) with experimental data from tissue distribution studies. Using parameter sensitivity analysis, the model was used to investigate the absorption characteristics of the compound and the probable causes of the low absorbed fraction. Results: Sensitivity analysis of absorption parameters was performed to understand the absorption characteristic of the compound in regard to permeability, solubility and intra-gut degradation. Taking in consideration the latter factor, the oral pharmacokinetics of the tested compound was satisfactorily predicted in rats. Conclusion: The PBPK simulation results suggest that chemical or/and bacterial degradation of the compound in the gastrointestinal tract may be a probable cause of the low bioavailability observed.
Based on the statistical thermodynamics and quantum mechanics, a simple mechanism for superconductivity has been proposed. With the method described in this paper, the transition temperatures can be easily determined, as a result, the efficiency in searching new superconductivity material is greatly improved.
Background: High cost of fishmeal (FM) adversely affects growth performance of African catfish fingerlings. There is need for alternative ingredients from affordable and available sources like plant proteins to meet growing feed demands in the larviculture of African catfish. Bambara nut waste meal (BNWM) is a proteinous, cheap and abundant, byproduct usually discarded or used to feed domestic chicken in Africa. Aims: To substitute fishmeal (FM) with bambara nut waste meal (BNWM) in five novel diet of larval African catfish Clarias gariepinus average weight 1.850±0.79 g and examine their growth and nutritional performances. Place and Duration: The experiment was carried out at the Fisheries and Hybrobiology, research unit department of Zoology University of Nigeria Nsukka between Nov.29 and 30 of December. Methodology: We substituted BNWM:FM per diet as follows; feed 1, (F1), 94:0%; feed 2, (F2), 89:5%; feed 3, (F3), 74:20%; feed 4, (F4), 59:35%; and feed 5, (F5), 39:55%. Other ingredients were vitamin premix, vitamin C and palm oil. Catfish larvae of average weight 1.850±0.79, stocked at 15 larvae aquarium-1 were fed with the experimental diets (F1-F5) for 30d. Results: African catfish larvae grew with optimal SGR of 8.2% day-1 for those fed with 39BNWM:55FM, F5 and 7.2% day-1 for those fed with 59BNWM:35FM, F4. The catfish fed with F1 94BNWM:0FM, and F2, 89BNWM:5FM, had lowest but similar SGR 5.0 and 5.3% day-1 respectively. Food conversion ratio (FCR) were similar for larvae fed with F5, F4 and F3 (P>0.05). Similarly FCR were similar for larvae fed with F1 and F2 (P>0.05). The weight gains of the larvae were best and similar for those fed 39BNWM:55FM, F5 (5.0 g) and F4 59BNWM:35FM, (4.5 g), but better than those fed 74BNWM:20FM, F3 (3.5 g). Those fed with F1 had least weight gain of (2.2 g). The protein efficiency ratio (PER) increased with FM inclusion but similar for catfish fed F5 6.78±0.02 and F4 6.33±0.05. The catfish PER was lowest for those fed all plant protein diet F1 94BNWM:0FM, PER, 3.97±0.04..3. Cost of feed increased with FM inclusion and fishmeal ratio (FMR) was highest for F5. Conclusion: The study shows that BNWM can supplement FM up to 59% in diets of African catfish. The lack of significant differences between FCR and SGR of catfish fed 39BNWM:55FM, F5 and F4 59BNWM:35FM is indicative of cost saving and benefits of BNWM. It shows that BNWM which is discarded in mills is a valuable resource that holds profitable potential in aquafeed production.
Aims: To ascertain the suitability for consumption of some selected refined vegetable oils commonly found and sold in most of the markets located in Nigeria. Study Design: Five different brands of vegetable oils commonly sold in Nigeria market, namely; Grand ground nut oil obtained from groundnut seed, turkey refined palm olein oil obtained from palm fruit, gino refined palm olein oil obtained from palm fruit, ideal refined palm kernel oil obtained from palm kernel seed and baron refined palm kernel oil obtained from palm kernel seed were subjected to Chemical analysis via determination of iodine value, acid value, peroxide value, saponification value and ester value of these oils. Place and Duration of Study: The chemical analysis was carried out in the Chemistry laboratory of the National Open University of Nigeria suited on Ahmadu Bello Way, Victoria Island, Lagos State between May – June, 2014. Methodology: The iodine value, acid value, Peroxide value and saponifcation value were determined by standard procedures described by AOAC (1980) while the ester value was determined by baltes, 1964 method. Results: The analysed chemical parameters shows that the iodine value of the oils are in the range of 21.83 g/100g to 79.95 g/100g, while the Saponification values of the oils are in the range of 235.62 mg/kOH/g to 274.19mg. The acid values and peroxide values of the oils are in the range of 0.39 mgKOH/g to 1.54 mgKOHg and 0.26 meq/kg – 1.17 meq/kg respectively while the ester value range from 206.70 mgKOH/g to 272.65 mgKOH/g. Conclusion: The result of the study shows that the oils are non drying oils of low saturation, slow to oxidation and rancidity, will remain liquid for a long time and are suitable for consumption.
This paper presents the results obtained during the development and implementation of two distributing motion control algorithms as part of an X-Y cutting table. One algorithm issues commands to the motor drivers on every sample cycle while the other does it only when a control point is reached. Both algorithms have the same input data set, control points that define the required path for the cutting torch. The analysis included two tests: A Wilcoxon rank sum test to find if the outcomes of the algorithms were different and a sign test to find if algorithms were able meet the design specifications. The analysis included four predefined specifications from the specimens, metal parts. All tests were based on a sample size seven, a .05 significance level and a two-tailed test. We found that algorithms outcomes were different and one of the algorithms was able to meet the design specifications of a part used as the test specimen.
Weight loss and electrochemical (open circuit potential (OCP), linear sweep voltammetry (LSV) and Potentiodynamic polarization (PDP)) techniques were used to assess the effectiveness of Gnetum africana leaves extracts as corrosion inhibitor for mild steel in 1.0 M hydrochloric acid (HCl) solution at 30-45°C. It was found that Gnetum africana leaves extracts retarded the dissolution of mild steel in 1.0 M HCl solution. The inhibition efficiency increased with increase in extract concentration and did reasonably well at increased temperature, which is suggestive of physical and chemical adsorption mechanism. Open circuit potential shows reduction of resistance polarization Rp with the addition of the Gnetum africana extract. Potentiodynamic polarization result suggests that Gnetum africana extracts functioned as mixed-type inhibitor. The adsorption of Gnetum africana extracts onto the mild steel surface followed Langmuir and Temkin adsorption isotherm models. The mechanism of physisorption of the extracts onto the mild steel surface is proposed from the trend of inhibition efficiency with temperature which is corroborated by the values of activation parameters obtained from the experimental data.
Aims: This work aims at finding out the effectiveness of a commercial micro-switch as the base component for building bump sensor for a design of a robotic fish. Methodology: A pair of micro switch (the type commonly used in computer mouse and similar devices) were assembled between the robot fish tip (actually a cone with the Mackerel fish profile) and the body, such that when the robot collides with a hard object, the switches will be depressed thus sending signal to its controller. The void between the switches were filled with collapsed polyurethane foam. The switches contact are continuously poled and the side that closes first is the side the robot is steered away from. False signals due to mechanical contact bounce was suppressed via software switch debounce algorithm. Test was focused on the debounce algorithm and the load to activate the switches. Furthermore, a modified IFD (compressive tests) on 1cm3 foam sample was perfomed. Results: A spectrum analyzer sampling of the undebouncce switches signal indicates the natural frequency of the vibration to be approximately 8.5kHz. Thus the controller will be sampling the switches contact at about 941.18 per second when operating at the design 8MIP (million instruction per second). The activation load test indicates that the minimum load to activate the left switch (3.42N) is less than that of the right (5.50N). The modified IFD test indicates that the force to compress the collapsed polyurethane foam by 50% is between 0.32N to 0.41N. A field test on the robot shows the robot respond well to the switch input as designed. Conclusion: The bump sensor as used in this research performed as expected despite the problems associated with mechanical switches. The limiting factor to this design as implemented is the minimum speed to activate the switches. The hydrodynamic drag force (0.00128N) is much less than the 5.86N force required to activate the sensor at the calculated minimum speed of 0.096 m/s. The force required to activate the switches is high due to the water proof coating used for them. The idea of the minimum speed to activate the bump switch is to ensure a fail safe operation when deployed. This design can be used for dark cave and also for cloudy water and where so much debris exists. It can also be used to augment other navigational techniques.
The animal skins and hides (wet salted/fresh goat skins, sheep skins and cow hides) were tanned using a rotating drum after it was aged for four days by enclosing it in an air tight environment using polyethylene bags. The properties of goat skins, sheep skins and cow hides studied were based on moisture absorption, thickness, breaking and tearing strength. The results of the analysis indicate that a thick strong leather material was obtained from the cow hides compared to goat and sheep skins. Softer leather was obtained from the sheep compared to goat. Therefore, goat and sheep gave best leather for shoe upper and upholstery while the cow hides gave best leather for sandals and other heavy leather products.
Aim: The aim of this study is to investigate Anopheles gambiae larval tolerance, density- as a function of survivorship- and the response of their detoxification enzymes to levels of various physico-chemical environmental factors present in their breeding sites. Study Design: Mosquito breeding sites were grouped into three different study zones A, B & C on the basis of human related activities (intensive agriculture, petrochemical industries and domestic activities, respectively) taking place within and/or around the breeding sites, followed by sampling of An. gambiae larvae and determination of larval density from all the breeding sites across the designated study zones. Some of the sampled larvae were reared into pupae and adult. Levels of 7 physical (pH, temperature, conductivity, transparency, total dissolved solids, dissolved oxygen and biological oxygen demand) and 6 chemical (sulphates, phosphates, nitrites, nitrates, carbon content and oil and grease) environmental factors were determined from mosquito breeding sites across the three study zones. Activities of the 3 major detoxification enzymes (P450, GST and α & β-esterases) were assayed on the sampled larvae and the emerged pupae and adult. Results: Our results showed high degree of tolerance of An. gambiae larvae to higher levels of these environmental factors. Also, the activities of the detoxification enzymes were higher in study zones A & C (which also recorded higher levels of the environmental factors) and were highly associated with most of the physico-chemical environmental factors. A deduced statistical model established the chemical composition in combination with some of the physical environmental parameters as influencing factors for larval density and producing an inductive effect on the three detoxification enzymes across the three life stages. Conclusion: These observations could have a significant impact on the environmental management and insecticide-based approach to vector control in Nigeria.
This study investigated the coag-flocculation performance of alum, pulverized snail shell coagulant (PSSC), and their blends under varying pH and coagulant dosage in removing turbidity from quarry effluent (QE) at room temperature. A laboratory bench-scale jar test was employed for the experiments. Coag-flocculation parameters such as coagulation rate constant, K11, coagulation half-time,τ_(1/2) etc were determined. The optimum pH was observed at 6.0, while the blend of 200.0 mg/L alum and 800.0mg/L PSSC achieved the optimum turbidity removal. Turbidity removal efficiency was recorded between 87.9% and 98.5% for various dosages and pH studied. The coagulation rate half-time, τ_(1/2) range from 13.8s to 972.45s for various dosages and pH studied. The use of PSSC blended with alum showed high level of potential, for the treatment of quarry effluent.