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The Geo-accumulation Index of Some Heavy Metals in the Roadsides Soils of Onitsha South Local Government Area Anambra State, Nigeria
Ochiagha K. E.,
Okoye P. A. C.,
Eboagu N. C.
Issue:
Volume 8, Issue 3, June 2020
Pages:
42-47
Received:
11 February 2020
Accepted:
1 April 2020
Published:
15 May 2020
Abstract: Heavy metals have a great ecological significance due to their toxicity and accumulative behaviour. Monitoring of their concentrations in the soils of our environment is very important. The geo-accumulation index (Igeo) in 11 stations in Onitsha South Local Government Area, (i.e Modeebelu Avenue, Ozomagana, Zik Avenue, Port Harcourt Road, Oguta Road, Iweka Road, Venn Road, Niger Street, Creek /Okwaraji Moore Street and Bida Road) were analysed. The soil pollution status of the area was investigated by analyzing the concentration of eight heavy metals (Mn, Ni, Zn, Cd, Cr, Fe, Cu and Pb) using Atomic Absorption spectroscopy (AAS). From the geo-accumulation index (Igeo) results obtained were; Mn values were mainly in class 5 for wet season and class 4 in dry season, Ni fell within the range of classes 2-3 in both seasons, Zn was in the range of classes 1-2 while Cr fell within the ranges of class 4-5 for both seasons. Cu was mainly within the range of class 2-3 in both seasons, while Pb fell within class 0 (with the exception of few locations). The Fe geo-accumulation for all locations was within the class of 0. These results revealed that Fe, Cd and Pb did not pollute the area but were polluted by Mn, Cr, Zn and Ni at various levels in both seasons.
Abstract: Heavy metals have a great ecological significance due to their toxicity and accumulative behaviour. Monitoring of their concentrations in the soils of our environment is very important. The geo-accumulation index (Igeo) in 11 stations in Onitsha South Local Government Area, (i.e Modeebelu Avenue, Ozomagana, Zik Avenue, Port Harcourt Road, Oguta Roa...
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Antisalmonellal Activities of Extracts, Fractions, Compounds and Semi-synthetic Flavonoid Derivatives from Tristemma hirtum P. Beauv (Melastomataceae)
Joseph Nandjou Kenfack,
David Tsafack Ngoudjou,
Beaudelaire Kemvoufo Ponou,
Jonas Kühlborn,
Borice Tapondjou Tsafack,
Rémy Bertrand Teponno,
Till Opatz,
Luciano Barboni,
Donatien Gatsing,
Léon Azefack Tapondjou
Issue:
Volume 8, Issue 3, June 2020
Pages:
48-58
Received:
31 March 2020
Accepted:
24 April 2020
Published:
27 May 2020
Abstract: The development and spread of resistance to currently available antibiotics is a major drawback in the treatment of microbial infections. Salmonellosis for example remains among the most common cause of morbidity and mortality in developing countries. This study aimed to evaluate the antisalmonellal potential of extracts, fractions, isolated compounds and semi-synthetic flavonoids from Tristemma hirtum P. Beauv. Bioguided fractionation by column chromatography of the EtOAc and n -BuOH fractions led to the isolation of eleven compounds including two new esterified glucuronide flavonoids namely: luteolin-3′-O-β-D-glucuronopyranosylbutyl ester (1), a mixture of compound 1 and quercetin-3-O-β-D-glucuronopyranosylbutyl ester (2). Chemical transformation mainly based on the prenylation of 6-hydroxyapigenin-7-O-β-D-glucopyranoside (5) afforded four new semi-synthetic flavonoid derivatives namely: 6, 4'-O-diprenylapigenin-7-O-β-D-glucopyranoside (5a), 8-C-prenyl-6, 4'-O-diprenylapigenin-7-O-β-D-glucopyranoside (5b), 8-C-prenyl-4'-O-prenylapigenin-7-O-β-D-glucopyranoside (5c), 4'-O-prenylapigenin-7-O-β-D-glucopyranoside (5d). The chemical structures of these compounds were assigned using NMR techniques, mass spectrometry and by comparison of their data with reported ones. The antisalmonellal activity was assessed by determining the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) using serial microdilution methods. The results showed that the MeOH extract and EtOAc fraction were active against all the bacteria tested with MICs ranging from 24 to 1536 µg/mL. Seven isolated compounds and three semi-synthetic compounds tested showed MIC values ranging from 16 to 256 µg/mL. Compounds 1, 3, 5a, 5c and 11 displayed the most potent antisalmonellal properties but were generally less potent than those of reference drugs. The activity of extracts and isolated compounds could be used as the starting point for the development of alternative phytodrugs against salmonellosis.
Abstract: The development and spread of resistance to currently available antibiotics is a major drawback in the treatment of microbial infections. Salmonellosis for example remains among the most common cause of morbidity and mortality in developing countries. This study aimed to evaluate the antisalmonellal potential of extracts, fractions, isolated compou...
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Synthesis and Characterization of Bioactive Cadmium (II) Complexes Derived from 4-Benzyloxybenzoylhydrazine with Different Aromatic Aldehydes
Rezaul Haque Ansary,
Jaber Al Mamun,
Md. Belayet Hossain Howlader
Issue:
Volume 8, Issue 3, June 2020
Pages:
59-65
Received:
6 May 2020
Accepted:
28 May 2020
Published:
17 June 2020
Abstract: The reactions of the ligand precursor 4-benzyloxybenzoylhydrazine (2) with cinnamaldehyde, salicylaldehyde, 2,4-dimethoxybenzaldehyde, 4-N,N dimethylaminobenzaldehyde, 4-methoxybenzaldehyde formed the ligands C6H5CH2OC6H4CONHN=CHR, where R=C6H5CH=CH, (3); C6H4(OH), (4); C6H3(OCH3)2, (5); C6H4N(CH3)2, (6); C6H4(OCH3), (7), respectively. The ligand precursor 4-benzyloxybenzoylhydrazine (2) was synthesized by the condensation reaction of ethyl-4-benzyloxybenzoate (1) with hydrazine hydrate. Ethyl-4-benzyloxybenzoate (1) was synthesized by the reaction of ethyl-4-hydroxybenzoate and benzyl bromide dissolved in acetone in presence of anhydrous potassium carbonate. By the reactions of the synthesized ligands with cadmium(II) acetate, a series of complexes [(C6H5CH2OC6H4CONHN=CHR)2Cd] were obtained, where R=C6H5CH=CH, (8); C6H4(OH), (9); C6H3(OCH3)2, (10); C6H4N(CH3)2, (11); C6H4(OCH3), (12). The complexes cannot be obtained via a template method. The compounds have been characterized by elemental analysis, conductivity measurements, UV-visible, FT-IR, 1H NMR spectral studies. The conductivity measurement data revealed that the complexes are non-electrolytic in nature. The UV-visible data of the complexes suggested the tetrahedral geometry of Cd(II) ion. The antibacterial results of the ligands (3-7) exhibited very low or no activity against pathogenic bacteria viz. gram positive (Bacillus anthracis, Staphylococcus aureus, Bacillus megaterium) and gram negative (Shigella flexneri, Escherichia coli, Shigella shiga), whereas their corresponding complexes (8-12) exhibited activity against the aforementioned bacteria but less than the standard drug, kanamycine. This implies that the activity showed by the complexes is solely responsible for the presence of Cadmium (II) ion.
Abstract: The reactions of the ligand precursor 4-benzyloxybenzoylhydrazine (2) with cinnamaldehyde, salicylaldehyde, 2,4-dimethoxybenzaldehyde, 4-N,N dimethylaminobenzaldehyde, 4-methoxybenzaldehyde formed the ligands C6H5CH2OC6H4CONHN=CHR, where R=C6H5CH=CH, (3); C6H4(OH), (4); C6H3(OCH3)2, (5); C6H4N(CH3)2, (6); C6H4(OCH3), (7), respectively. The ligand p...
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Synthesis and Characterization of Vinyl Acetate Grafted onto Industrial Cellulose
Chiagozie Michael Ekwunife,
Vincent Ishmael Egbulefu Ajiwe,
Collins Chibuzor Odidika,
Uchenna Emmanuel Amalu
Issue:
Volume 8, Issue 3, June 2020
Pages:
66-71
Received:
21 May 2020
Accepted:
8 June 2020
Published:
23 June 2020
Abstract: This study was aimed at investigating the synthesis and characterization of vinyl acetate grafted on Industrial Cellulose. Vinyl acetate monomer was grafted onto Industrial cellulose using benzoyl peroxide as initiator at varied temperatures. The Industrial cellulose-g-poly(vinyl acetate) was orange in colour. The effect of initiator concentration, monomer concentration and temperature on percentage grafting and grafting efficiency of the product was determined. Both percentage grafting and grafting efficiency increased with initiator concentration and monomer concentration for the industrial cellulose-g-poly(vinyl acetate). The percentage grafting and grafting efficiency increased with temperature from 60°C – 70°C then decreased after 70°C for the sample. The graft copolymer was analyzed and characterized using various tests, which included Fourier transformed infrared spectrophotometer, physico-mechanical tests which were, hardness test with durometer shore hardness tester, density with Monsanto Densitron 2000, softening point tester with HDT/Vicat Test Station. Moreover, adsorption studies of bromothymol blue onto the sample was done with Ultraviolet-visible spectrophotometer. The results of the FTIR confirmed the presence of O-H of alcohol (3404 cm-1), C=O of esters (1645 cm-1), N-H of protein (2272 cm-1), C-H of methyl and methylene (2933 cm-1), and C-O of esters (1122 cm-1) in the Industrial cellulose-g-poly(vinyl acetate). The result of the hardness showed that the Industrial cellulose-g-poly(vinyl acetate) was 87D, the density was 0.95mg/m3, and the softening point was 115°C - 135°C. The percentage of bromothymol blue removed from aqueous solution was 72.4% for industrial cellulose-g-poly(vinyl acetate). The rate constants for the Industrial graft copolymer was determined using pseudo first order kinetics and it gave 3.59 x 10-2 min-1. The research showed that Industrial cellulose-g-poly(Vinyl acetate) could be used in the adsorption of bromothymol blue (dye) in aqueous solution.
Abstract: This study was aimed at investigating the synthesis and characterization of vinyl acetate grafted on Industrial Cellulose. Vinyl acetate monomer was grafted onto Industrial cellulose using benzoyl peroxide as initiator at varied temperatures. The Industrial cellulose-g-poly(vinyl acetate) was orange in colour. The effect of initiator concentration,...
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Study of Ellipsometry of Swelling of Styrene-acrylic Bentonite-containing Copolymer Composites
Ganiyev Bakhtiyor Shukurullayevich
Issue:
Volume 8, Issue 3, June 2020
Pages:
72-76
Received:
25 March 2020
Accepted:
10 June 2020
Published:
28 June 2020
Abstract: In this work, the study of copolymer acrylic films was carried out on a laser photoelectric ellipsometer LEF-ZM-1. In this work, we consider a chemical sensor based on an integrated optical sensing element, propose structural schemes of IOCS, as well as conduct studies on a simulation model and assess the potential for detecting changes in the concentration of various substances. For this, in the course of the work, we studied the change in the refractive indices of polymer films with a Navbahor bentonite content of 5 wt.%, Depending on the time of their swelling in aqueous solutions containing Cr ions. The most important characteristics for acrylic copolymers are mechanical strength and sorption, since it is the values of these parameters that impose significant restrictions on the field of their application. Therefore, in this article, in addition to ellipsometry, the effect of the initiator concentration on the absorption properties of polymer composites and the influence of the synthesis temperature on the absorption properties of copolymer composites containing Navbahor bentonite are also studied. During the study, it was clarified that acrylic mineral-containing composites obtained at 42°C have the maximum sorption ability.
Abstract: In this work, the study of copolymer acrylic films was carried out on a laser photoelectric ellipsometer LEF-ZM-1. In this work, we consider a chemical sensor based on an integrated optical sensing element, propose structural schemes of IOCS, as well as conduct studies on a simulation model and assess the potential for detecting changes in the conc...
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