ASSESSMENT OF PERIODS OF SAND PRIMING AND HYDRO-PRIMING ON THE GERMINATION OF AFRICAN EBONY (Diospyros mespiliformis Hochst)

Diospyros mespiliformis (Hochst) is a multipurpose, agro-forestry tree species with diverse environmental and ecological significances. However, low percentage germination associated with its seeds has limited its domestication. To overcome this challenge, there is need to adopt cheap, fast, safe, natural and adoptable physiological techniques such as sand priming and hydro-priming. There is paucity of quantified information on natural and safe methods of relieving dormancy as sand priming and hydro-priming. Most of methods of breaking dormancy as use of acid are not simple, safe and adoptable by farmers who practices agro-forestry. In the light of this, these experiments were conducted to assess the periods of sand priming (0, 2, 4, 6 and 8 weeks) and hydro-priming (0, 2, 4, 6 and 8 weeks) on the germination of D. mespiliformis. Both experiments were laid down in completely randomized design with four replicates. Mean germination times were calculated, and result revealed that a significant increase in percentage germination was recorded with increasing periods of exposing seeds to sand priming up to four weeks. The percentage germination ranged between 28%-93.25% for control (0) and four weeks sand priming respectively. Least value of 8.92 day was recorded for mean germination time of control (0 sand priming). A significant increase in percentage germination was recorded with increasing hours of hydro-priming up to 24 hours. The percentage germination was ranged between 25% - 100% for control (0) hour to 24 hours. Highest germination percentages were recorded in seeds subjected to sand priming for 4weeks (93.25%) and those hydro-primed for 24hours (100%). These results are recommended for mass production of D. mespiliformis in agro-forestry nurseries. &nbsp

Assessment of Reliability and Availability of Series-Parallel Sub-Systems

The paper presents the explicit expressions for measuring reliability parameter  of systems, Graphs were plotted to highlight important results. Results have shown that measures of system effectiveness such MTSF, system availability and profit increases with repair rates and decreases with failure rates.The developed model helps in determining the optimal maintenance strategies which ensure the maximum overall availability of the system. The optimum values of failure and repair rates for each subsystem were given. It is observed that the first subsystem is having the maximum availability with (97%). The optimum values of failure and repair rates for maximum availability level for each subsystem is also shown. Keywords: Mean time to system failure, Availability, Reliability, Maintenance and Subsystem

Fuzzy-PID Controller for Azimuth Position Control of Deep Space Antenna

The Deep Space Antennas are essential in achieving communication over very large distances. However, the pointing accuracy of this antenna needs to be as precise as possible to enable effective communication with the satellite. Therefore, this work addressed the pointing accuracy for a Deep Space Antenna using Fuzzy-PID control technique by improving the performance objectives (settling time, percentage overshoot rise time and mainly steady-state error) of the system. In this work, the PID controller for the system was first of all designed and simulated after which, a fuzzy controller was also designed and simulated using MATLAB and Simulink respectively for the sake of comparison with the fuzzy-PID controller. Then, the fuzzy-PID controller for the system was also designed and simulated using MATLAB and Simulink and it gives a better performance objective (rise time of 1.0057s, settling time of 1.6019s, percentage overshoot of 1.8013, and steady-state error of 2.195e-6) over the PID and fuzzy controllers respectively. Therefore, the steady state error shows improved pointing accuracy of 2.195e-6

Anti-nociceptive and anti-inflammatory activities of methanol root extract of Andropogon gayanus Kunth (Poaceae) in rodents

Background: Andropogon gayanus is widely used in traditional medicine for various ailments such as postpartum pain, bronchitis and oedema. Objective: This study evaluated the anti-nociceptive and anti-inflammatory activities of methanol root extract of A. gayanus in experimental rodents. Methods: Phytochemical screening tests and acute toxicity studies were carried out. Analgesic activity using acetic acid-induced writhing response and hot plate test in mice, formalin-induced pain and carrageenan-induced paw oedema in rats were evaluated at doses of 250, 500 and 1000 mg/kg of the extract. Results: Oral median lethal dose was >5000 mg/kg in both mice and rats. The extract significantly (p<0.01) decreased the number of writhing movements at all tested doses. It also significantly (p<0.05) increased the mean reaction times. A significant (p<0.05) decrease in mean pain scores was also observed in both phases of the formalin test at 1000 mg/kg. The extract at 1000 mg/kg significantly (p<0.05) reduced the oedema at the 1st hour, while at the 5th hour, all doses tested significantly reduced the oedema. Conclusion: The methanol root extract of Andropogon gayanus possesses antinociceptive and anti-inflammatory activities. Keywords: Andropogon gayanus, Analgesic, Anti-inflammatory, Pai

Structural and dielectric properties of Ba(Ti0.96Sn0.01Zr0.03)O3 perovskite nanoparticles fabricated by mechanochemical synthesis route

Lead free Nanocrystalline BaTiO3 doped with Sn and Zr is prepared by a combination of solid-state reaction and high energy ball milling (HBM) technique in a temperature range 30–150 °C, over a frequency range 40 Hz – 1 MHz. A single-phase nanocrystalline sample with ABO3 type of perovskite structure with cubic symmetry was confirms by XRD diffraction. The crystallite and grain size determined from Scherrer equation and intercept method are 38.2 nm and 46.13 nm respectively. FE-SEM images show samples are dense and have different microstructures with certain amount of porosity. A grain size of 46.13 nm is obtained by using linear intercept method. Room temperature (RT) variation of ′and tan as a function of frequency of the modified BT system has also been studied. Variation of dielectric properties with frequency shows the usual behaviour of dielectric materials i.e decrease of the value of ′ with the increase of frequency. A dielectric anomalies is observed corresponding to phase transitions viz tetragonal to cubic (− ) at 70oC. These effect can guide to design the nanostructure for various practical applications of MLCC

Ameliorative Effect of Vitamin C on Alterations in Thyroid Hormones Concentrations Induced by Subchronic Coadministration of Chlorpyrifos and Lead in Wistar Rats

The present study evaluated the ameliorative effect of vitamin C on alteration in thyroid hormones induced by low-dose subchronic coadministration of chlorpyrifos (CPF) and lead (Pb). Forty Wistar rats were divided into 4 groups of 10 animals each. Groups I and II were administered soya oil (2 mL/kg) and vitamin C (100 mg/kg), respectively. Group III was coadministered CPF (4.25 mg/kg ~1/20th LD50) and Pb (250 mg/kg ~1/20th LD50), respectively. Group IV was pretreated with vitamin C (100 mg/kg) and then coadministered with CPF (4.25 mg/kg) and Pb (250 mg/kg), 30 min later. The regimens were administered by gavage for a period of 9 weeks. The marginal decrease in serum triiodothyronine and thyroxine and the significant increase in the concentrations of thyroid stimulating hormone and malonaldehyde in the group coadministered with CPF and Pb were ameliorated by vitamin C partly due to its antioxidant properties

Effects of rice husk ash on durability of self-compacting concrete made with cassava peel ash

Self-compacting concrete (SCC) is a highly flowable concrete with improved strength and surface smoothness. The preparation of SCC requires high amount of cement. This utilizes tremendous amount of energy and releases carbon dioxide into the atmosphere. It is critical to reduce CO2 emissions during Portland cement (PC) manufacture by partially replacing cement in the SCC. This study evaluates the durability characteristics of SCC produced using cassava peel ash (CPA) combined with rice husk ash (RHA) at 5, 10, 15, 20, and 25 percent cement replacement levels respectively. The effects of water absorption, H2SO4 attack, MgSO4 attack, and high heat on SCC made with CPA and RHA blends were examined. The results show that, as CPA and RHA proportions rise by approximately 5% CPA and 10% CPA+RHA substitution, SCC compressive strength equates to design strength (grade 35). It was also discovered that CPA and RHA both enhance resistance to H2SO4 and MgSO4 degradation, but perform poorly when exposed to elevated temperatures when compared to the control specimen. However, when CPA is utilized with RHA in SCC, the rate of water absorption is reduced to a minimum due to an enhanced pore structure of the CPA-SCC specimen. Generally, a 5% CPA content is considered as the optimum replacement of cement for self-compacting concrete with grade 35

Multidrug resistance by microorganisms: a review

Multiple drug resistance (MDR) is the ability of some microorganisms to resist the actions of multiple antimicrobial agents. MDR include those resistant to multiple antibacterial, antifungal, antiviral, and anti-parasitic drugs. Similar activities of some microorganisms to certain chemical (drug) that would normally kill them or limit their growth is called antimicrobial resistance (AMR). Multi drug resistance can be classified as primary resistance, secondary resistance, intrinsic resistance, extensive resistance and clinical resistance. The classes of antibiotics that fall victim of resistance include beta-lactams, glycopeptide, aminoglycosides, sulphonamides, cephalosporins etc. The mode of action of antimicrobial drug includes cell wall synthesis inhibitors, protein synthesis inhibitor, blockage of key metabolic pathways, nucleic acid synthesis inhibitors etc. Bacteria often become resistant and this could be through one of several biochemical mechanisms such as mutation, destruction or inactivation and efflux or genetic transfer of materials between bacteria by several means such as conjugation, transformation and transduction. The mode of action of MDR protozoa occurs through decrease of drug uptake, the export of drugs from the parasite by P-glycoproteins and other traffic ATPases etc. The mode of action of MDR helminths occurs through genetic changes in the drug target, changes in drug transport, drug metabolism etc. The mode of action of antiviral drugs usually target viral DNA polymerase having the reverse transcriptase activity to inhibit the viral replication. The mode of action of MDR fungi occurs as they have learnt to modify the antifungal drug targets or most commonly increase the efflux of the incoming drugs There are various ways to reverse this resistance such as washing hands after seeing each patient, the public should wash raw fruit and vegetables thoroughly to clear off both resistant bacteria and possible antibiotic residues, avoid the misuse of antibiotics, etc