Nigerian Journal of Science and Environment

Design, synthesis and evaluation of antibacterial and antifungal quinazolinone derivatives bearing Thiazole Schiff Base Moiety

E.C Otutu — 2025-01-21

Various quinazolinone derivatives with thiazole substituent was synthesised in good yields starting from 4-chloroanthranilic acid and ethyl-2-aminothiazole acetate in condensation reactions. The synthesized compounds were characterised using proton and carbon-13 nuclear magnetic resonance (¹H NMR, ¹³C NMR), Fourier Transform Infrared (FT-IR), and mass spectrometry (GCMS) analyses. The antibacterial activity of the compounds against a number of micro-organisms was tested by the Micro broth dilution method. It was found that the synthesised compounds exhibited variable antimicrobial activity against Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) and Gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus) as well as the fungus (Candida pseudotropicalis). It was also found that compounds 6c and 6d among others were the most effective on both Gram-negative and Gram-positive bacteria. The two compounds were also found to be the most effective against the fungus, Candida pseudotropicalis. The results of the antimicrobial activity suggest that compounds 6c and 6d are potent antimicrobial agents.

Translating nested and multiple stochastic integrals in the Wiener functional space through the moment inequalities

V.O. Ojo-Orobosa — 2025-01-21

Various techniques have been adopted in the past, in translating nested and multiple stochastic integrals to the Wiener functional space. However, this paper considers a new method of moving nested and multiple stochastic integrals into the Wiener functional space. Based on the existence of nested integrals and multiple stochastic integrals in moment inequalities, we derived a means of representing and expressing them in the Wiener functional space which is referred to as the moment inequalities formula. Hence, this paper established that the multiple stochastic nested integrals in Moment inequalities are one translating formula onto the Wiener functional space. This result was achieved by showing that the log-Sobolev inequality implies the exponential integrability of the square of the Wiener functional whose derivatives are essentially bounded.

Conjugacy classes in order- preserving transformation semi groups with injective contraction

J.O. Emunefe — 2025-01-21

Enumerating the elements within transformation semigroups poses a significant challenge. Prior knowledge has been more on the injective order-preserving and order-decreasing transformation semigroup, a sub-semigroup of the injective transformation semigroup. This work categorized elements within the injective order-preserving sub-semigroup with contraction, arranging them into conjugacy classes using a path decomposition approach based on circuit and proper paths. Furthermore, these conjugacy classes were organized according to the number of images. A general expression was derived for the number of conjugacy classes in the injective order-preserving contraction transformation semigroup. We found that the number of conjugacy classes in this transformation is precisely given by the sequence A000070 (OEIS). This alignment suggests a profound relationship between the structure of these transformations and the theory of partitions (number theory), opening up new avenues for research and analysis.

Power series variational iteration method for fractional order boundary value integro-differential equations with certain orthogonal polynomials

E.K. Johnson — 2025-01-21

The motivation behind this work is the recent advances in literature for seeking numerical techniques for fractional order boundary value integro-differential equations. The Power Series Approximation Method (PSAM) is a new approach for the numerical solution of generalized Nth-order boundary value problems. The proposed method is structurally simple with well-posed mathematical formulas. It involves transforming the given boundary value problems into a system of Ordinary Differential Equations together with the boundary conditions prescribed. Thereafter, the coefficients of the power series solution are uniquely obtained with a well-posed recurrence relation along the boundary, which leads to the solution. The unknown parameters in the solution are determined at the other boundary. This finally leads to a system of algebraic equations, which, upon solving, yields the required approximate series solution. We hence extend the Power Series Variational Iteration Method through systematic modification for the solution of fractional order boundary value integrodifferential equations with Mamadu-Njoseh polynomials as basis functions. Two examples of the Fredholm type with resulting numerical evidence show that the method is accurate and reliable with an excellent convergence rate for both illustrations considered, with results presented in graphs and tables.

Performance evaluation and characterization of fabricated silver nitrate doped DSSC sensitized with dye extracted from Corchorus olitorius L

S.O. Malumi — 2025-01-21

This study concentrates on the conventional dye sensitized solar cell (DSSC). This type of solar cell is generally made from components such as photo anode support, photo sensitizer (dye), electrolyte and counter electrode. This research investigates the properties of the photosensitizer which was locally sourced from our environment, was analyzed. The effect of the dopant on the absorbance spectrum of the chlorophyll based dye was also studied. The optical properties of the natural dyes showed that the dye-sensitized material exhibits an intense absorption broad band of 620-720 nm in the visible light region indicating the absorption of red light from the photons with a more prominent peak 659 nm. The structural characterization of the film was investigated using scanning electron microscopy (SEM), energy dispersive x-ray (EDX) and x-ray diffraction (XRD). The solar cells were finally prepared by sandwiching the TiO₂ photoanode with the counter electrode. The electrical properties of the fabricated solar call was analyzed by the use of a solar simulator which resulted to an efficiency of 0.05 %.This was calculated from the experimental values of short circuit current (I_sc), open circuit current voltage (V_oc), fill factor (ff) as 0.389 V, 0.242 mAcm^-2 and 0.48 respectively.

Analyzing the structural, optoelectronic, and optical properties of ZrS nanostructured material by adding silver (Ag) dopant to its lattice.

O.S Shaka — 2025-01-21

In this study, a range of (0.01-0.03) mol was used to synthesize silver doped ZrS through electrodeposition. A three-electrode system was employed in the synthesis. Platinum is used for the anode, silver and silver chloride (Ag/AgCl) are used for the reference electrode, and FTO (fluorine-doped tin oxide) is used for the cathode. The ZrS and Ag/ZrS XRD patterns showed the materials are polycrystalline with distinct phase orientation planes. An intense peak, indexed at (111) and showing values between 23.59^o and 62.62^o , displays a heavily dampened peak plane at (111). The micrograph of the ZrS material shows a presence of hexagonal structure material along with precipitate. The presence of various silver concentrations results in particle clumping and a uniformly coated substrate surface. In the visible region, the Ag/ZrS material displays a distinct absorption band, which is attributed to the silver surface plasmon resonance. The wavelength of the surface plasmon resonance band is determined by the size, shape, and dielectric properties of the silver material and the surrounding ZrS material. The energy band structure of ZrS increases from 2.32 to 2.51 eV with increasing silver molarity due to silver incorporation within the ZrS lattice.

Evaluation of the concentration and distribution of selected air pollutants in some towns in Ukwuani LGA of Delta State, Nigeria.

G.E. Reuben — 2025-01-21

Abstract The research investigated the spatial distribution and concentrations of air pollutants, across six locations in Delta State, Nigeria which include two roadsides (Utagba-Unor junction, Obiaruku, and Umutu junction along Agbor-Abraka Road), two residential areas (Ebedei-Umueziogoli Quarters and Ebedei-Adonishaka), Ebedei-Unor near gas plant and a control site near the Ethiope River at Adonishaka. The ambient air quality of the locations were measured with Aeroqual Gas Monitoring Kit (ASTM D3249-95, 2011) with sampling done in the morning, afternoon, and evening period over seven consecutive days during the core of dry and wet seasons. The measured concentrations ranged obtained were CO (0.5 ± 0.07–3.29 ± 0.31 µg/m³), CO₂ (2.00 ± 0.04–7.39 ± 0.18 µg/m³), H₂S (0.00 ± 0.00–0.77 ± 0.12 µg/m³), NO (0.00 ± 0.00– 0.83 ± 0.06 µg/m³), NO₂ (0.14 ± 0.05–4.04 ± 0.35 µg/m³), and CH₄ (0.40 ± 0.06–4.33 ± 0.35 µg/m³). CO was observed to have the highest concentrations at Ebedei-Adonishaka, while Ebedei-Unor recorded the highest concentration of CO₂, H₂S, NO, NO₂, and CH₄. Seasonal variations was observed with more pollutant during the dry season compared to wet season.

Surveying of radioactivity concentration of U-238, Th-232 and K- 40 and evaluation of radiological health parameters on Nigeria Coastal Line

I.K. Ogungbemi — 2025-01-21

Activities around the Atlantic Ocean coastline region have greatly increased of resent due to industrial and commercial establishments. This study quantified the natural radionuclide contents in the waters along the Atlantic Ocean in West Africa, with special interest in the Nigerian coastline region. The study then evaluated the health risks associated with these natural radionuclides for each population living along the coastline. Several water samples were collected offshore and onshore from five different locations from south-west to south-south in clean plastic bottles and kept in the laboratory for 30 days. In preparation for the use of the HPG detector used, which is of serial number 9744, model GC8023 has a relative efficiency of 80% and a resolution of 2.3 keV full width at half maximum (FWHM) at 1.33 MeV. The results show variation in concentration levels in U238, Th232, and K40 across the coastline. The absorbed dose increases from the south-west down to the south-south of the coastline, ranging from 14.73 and 28.78 nGyhr^-1 in the south-west, while in the south-south it is 18.75 and 26.18 nGyhr^-1 . The indoor effective dose is in the range 0.072 to 0.141 mSv/y and the outdoor effective dose ranges from 0.018 - 0.035 mSv/y. The increase in absorbed dose is due to K-40 from the agricultural activities in the region and also the crude oil exploration use of radionuclides in oil fields. The excess lifetime cancer risk within the region is slightly comparable to the tolerable values set by regulatory bodies.

Assessment of bio–concentrated heavy metals in commonly consumed fish in Sapele Delta State

O.H. Erhenhi — 2025-01-21

Heavy metal contamination in aquatic environments poses significant risks to both ecosystems and human health. Fish, as a major protein source, can accumulate toxic metals, making it essential to monitor their safety for consumption. This study assesses the concentration of six heavy metals, lead (Pb), chromium (Cr), nickel (Ni), cadmium (Cd), mercury (Hg), and barium (Ba) in the liver, kidney, and tissue of three selected fish species (Oreochromis niloticus, Puntius brevis, and Electrophorus electricus) from Sapele Markets, Delta State, Nigeria. The analyses focused on six heavy metals: lead (Pb), chromium (Cr), nickel (Ni), cadmium (Cd), mercury (Hg), and barium (Ba) in the liver, kidney, and tissue of the fish..For all the sampled fish species ,most metals were below WHO limits, except for cadmium, which has already reached a level of great concern. Barium, chromium, and mercury were negligible across all species. Additionally, the length-weight relationship indicated negative allometric growth pattern in the three fish species, with condition factors (k) less than 1, suggesting the fish were in poor health. Stomach content analyses revealed that O. niloticus is herbivorous, P. brevis is carnivorous, and E. electricus is a bottom feeder. These findings suggest that while most heavy metal concentrations are within safe limits, the slightly elevated cadmium levels in O. niloticus tissue pose a potential health risk, emphasizing the need for regular monitoring and intervention to safeguard public health.

Microorganisms in deteriorating Nigerian melon (Colocynthis citrullus L.) soup (egusi): Heat susceptibility profile and nutrient degradation potential

C.S. Odibe — 2025-01-21

Egusi is a popular melon (Colocynthis citrullus L.) soup in Nigeria that deteriorates within 24 hours. The study aimed to identify microorganisms associated with spoilage of egusi soup, determine their heat susceptibility profile and nutrient degradation capabilities. Nutrient and Potato Dextrose agar were used to isolate microorganisms from egusi soup obtained from 5 restaurants and kept on the shelf for three consecutive days. The isolates were identified by standard procedure involving microscopy and biochemical tests. Egusi spoilage capabilities of the isolates were tested using losses of nutrients (lipid, carbohydrate, protein) and changes in turbidity and pH as indicators after 24 h. The isolates were also tested for survival at varying temperatures (30-80⁰C). The bacteria isolated were, Bacillus sp., Enterococcus sp., Streptococcus sp., Staphylococcus sp., Escherichia coli and Klebsiella sp. while the fungi were Aspergillus niger, Penicillium sp., Microspora sp. and Aphanoascus sp. Changes in pH and turbidity of egusi were minimal (pH, 6.0-6.2; turbidity reduction, 1.0-1.2%) without interspecies differences (P>0.05) while nutrient losses were 5.5-43.2% with inter-species differences for protein and lipid (P<0.05). Most isolates tolerated a temperature range of 30-50⁰C with only Bacillus sp surviving at 80⁰C. Fungal isolates were less tolerant of heat (≤40⁰C). In conclusion, the isolates depleted egusi nutrients and tended to be thermophilic, thereby indicating the need for additional measures to complement 50-60⁰C treatment for preservation. The findings present an insight into the strategy to be adopted to ensure microbial and shelf stability of egusi