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Olatunde Sunday Eludoyin,Vitus Chinonso Odimegwu 강원대학교 산림과학연구소 2018 Journal of Forest Science Vol.34 No.4
The study investigated the concentrations of Pb in soil, air and fruit of C. sinensis in selected landuse types in Port Harcourt Metropolis, Rivers State, Nigeria. Five fruits of C. sinensis were collected randomly in residential, commercial, industrial and natural forest (control). The weight, length and width of the C. sinensis fruits were measured. A total of three soil samples were collected around the C. sinensis trees where the fruits were collected into well labeled polythene bags and thereafter taken to laboratory for analysis. Pb concentrations in C. sinensis and soil samples were analysed using atomic absorption spectrophotometer (AAS). The concentration of Pb in the air was measured for 14 days using Aeroquel 500. The significant relationship between Pb concentration in the C. sinensis fruits, soil and air was determined using Spearman’s rank correlation. Findings showed that the mean weight and width of C. sinensis fruits were highest in the residential landuse while the mean length of C. sinensis fruits was highest in the industrial landuse. However, the mean Pb concentration in the C. sinensis fruit was highest in the industrial landuse (0.46±0.15 mg kg-1), commercial landuse (0.33±0.09 mg kg-1) and the least was found in the natural forest (0.25±0.06 mg kg-1). The mean Pb concentration in the soil was highest in the industrial landuse (0.177±0.16 mg kg-1) and commercial landuse (0.121±0.10 mg kg-1). However, the mean Pb concentration in the air was highest in the industrial landuse (0.85±0.09 mg kg-1) and followed by commercial landuse (0.30±0.17 mg kg-1). The correlations between the Pb concentration in the C. sinensis fruit and soil (r=0.768, p<0.05) and air (r=0.642, p<0.05) were significant. The study concluded that the Pb concentration in the C. sinensis fruits was higher than the WHO standard; hence people should be discouraged to consume them, especially those from the industrial and commercial areas.
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Olatunde Sunday Eludoyin,Olawale Oluwamuyiwa Aladesoun 강원대학교 산림과학연구소 2021 Journal of Forest Science Vol.37 No.4
The study examined the influence of climate and soil dynamics on vegetation health across the ecological zones in Rivers State, Nigeria. MODIS imagery was used to assess the vegetation health through NDVI and point grid pattern of meteorological data for total precipitation (TP), air temperature (AT), soil moisture (SM) and soil temperature (ST) of 2000, 2003, 2006, 2009, 2012 and 2015 were used for the study. Descriptive and inferential statistics were used for data analysis. Findings showed that NDVI ranged between 0.420 and 0.612 in the freshwater swamp (FWS) while between 0.465 and 0.611 in the rainforest and the NDVI in the mangrove was generally low. The highest mean AT was experienced in the mangrove ecological zone and the least was experienced in the rainforest. The mean SM was generally highest in the rainforest with highest value in 2000 (774.44 m3/m3). The ST was highest in the mangrove and the least was experienced in the rainforest while the TP was highest in the mangrove. NDVI correlated significantly with SM (r=0.720; p<0.05) and ST (r= -0.493; p<0.05). NDVI, SM, TP and ST significantly varied among the ecological zones. Regression analysis showed that vegetation health was significantly related to the combination of soil temperature and soil moisture (R2=0.641; p=0.000). Thus, monitoring the factors that affect vegetation health in a changing climate and soil environments is highly required.
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Monitoring Process Variability Using Double Moving Average Control Chart
Olatunde A. Adeoti,Abayomi A. Akomolafe,Femi B. Adebola 대한산업공학회 2019 Industrial Engineeering & Management Systems Vol.18 No.2
Enhancing the ability of control charts for detecting shifts of small magnitude in the process parameter is desirable. In this paper, a double moving average control chart based on the sample standard deviation is proposed for detecting shifts in the process variability. The performance of the proposed control chart is investigated in terms of average run length and compared with existing control charts. The results show that the proposed control chart performs better than the existing control charts. A numerical example based on simulated and real-life data is provided to demonstrate the application of the proposed chart.
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E. Olatunde Farombi 한국환경성돌연변이발암원학회 2005 한국환경성돌연변이·발암원학회지 Vol.25 No.3
The genotoxic effect of antimalarial drugs amodiaquine (AQ), mefloquine (MQ) and<br/> halofantrine (HF) was investigated in rat liver cells using the alkaline comet assay. AQ, MQ and HF at concentrations between 0-1000 μmol/L significantly increased DNA strand breaks of rat liver cells dosedependently. The order of induction of strand breaks was AQ > MQ > HF. The rat liver cells exposed to AQ and HF (200 and 400 μmol/L) and treated with (Fpg) the bacterial DNA repair enzyme that recognizes oxidized purine showed greater DNA damage than those not treated with the enzyme, providing evidence that AQ and HF induced oxidation of purines. Such an effect was not observed when MQ was treated with the enzyme. Treatment of cells with catalase, an enzyme inactivating hydrogen peroxide, decreased significantly the extent of DNA damage induced by AQ, and HF but not the one induced by MQ. Similarly quercetin, an antioxidant flavonoid at 50 μmol/L attenuated the extent of the formation of DNA strand breaks by both AQ and HF. Quercetin, however, did not modify the effects of MQ. These results indicate the genotoxicity of AQ, MQ and HF in rat liver cells. In addition, the results suggest that reactive oxygen species may be involved in the formation of DNA lesions induced by AQ and HF and that, free radical scavengers may elicit protective effects against genotoxicity of these antimalarial drugs.
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Eludoyin, Olatunde Sunday,Odimegwu, Vitus Chinonso Institute of Forest Science 2018 Journal of Forest Science Vol.34 No.4
The study investigated the concentrations of Pb in soil, air and fruit of C. sinensis in selected landuse types in Port Harcourt Metropolis, Rivers State, Nigeria. Five fruits of C. sinensis were collected randomly in residential, commercial, industrial and natural forest (control). The weight, length and width of the C. sinensis fruits were measured. A total of three soil samples were collected around the C. sinensis trees where the fruits were collected into well labeled polythene bags and thereafter taken to laboratory for analysis. Pb concentrations in C. sinensis and soil samples were analysed using atomic absorption spectrophotometer (AAS). The concentration of Pb in the air was measured for 14 days using Aeroquel 500. The significant relationship between Pb concentration in the C. sinensis fruits, soil and air was determined using Spearman's rank correlation. Findings showed that the mean weight and width of C. sinensis fruits were highest in the residential landuse while the mean length of C. sinensis fruits was highest in the industrial landuse. However, the mean Pb concentration in the C. sinensis fruit was highest in the industrial landuse ($0.46{\pm}0.15mg\;kg^{-1}$), commercial landuse ($0.33{\pm}0.09mg\;kg^{-1}$) and the least was found in the natural forest ($0.25{\pm}0.06mg\;kg^{-1}$). The mean Pb concentration in the soil was highest in the industrial landuse ($0.177{\pm}0.16mg\;kg^{-1}$) and commercial landuse ($0.121{\pm}0.10mg\;kg^{-1}$). However, the mean Pb concentration in the air was highest in the industrial landuse ($0.85{\pm}0.09mg\;kg^{-1}$) and followed by commercial landuse ($0.30{\pm}0.17mg\;kg^{-1}$). The correlations between the Pb concentration in the C. sinensis fruit and soil (r=0.768, p<0.05) and air (r=0.642, p<0.05) were significant. The study concluded that the Pb concentration in the C. sinensis fruits was higher than the WHO standard; hence people should be discouraged to consume them, especially those from the industrial and commercial areas.
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Heme Oxygenase-1 as a Potential Therapeutic Target for Hepatoprotection
Farombi, Ebenezer Olatunde,Surh, Young-Joon Korean Society for Biochemistry and Molecular Biol 2006 Journal of biochemistry and molecular biology Vol.39 No.5
Heme oxygenase (HO), the rate limiting enzyme in the breakdown of heme into carbon monoxide (CO), iron and bilirubin, has recently received overwhelming research attention. To date three mammalian HO isozymes have been identified, and the only inducible form is HO-1 while HO-2 and HO-3 are constitutively expressed. Advances in unveiling signal transduction network indicate that a battery of redox-sensitive transcription factors, such as activator protein-1 (AP-1), nuclear factor-kappa B (NF-${\kappa}B$) and nuclear factor E2-related factor-2 (Nrf2), and their upstream kinases including mitogen-activated protein kinases play an important regulatory role in HO-1 gene induction. The products of the HO-catalyzed reaction, particularly CO and biliverdin/bilirubin have been shown to exert protective effects in several organs against oxidative and other noxious stimuli. In this context, it is interesting to note that induction of HO-1 expression contributes to protection against liver damage induced by several chemical compounds such as acetaminophen, carbon tetrachloride and heavy metals, suggesting HO-1 induction as an important cellular endeavor for hepatoprotection. The focus of this review is on the significance of targeted induction of HO-1 as a potential therapeutic strategy to protect against chemically-induced liver injury as well as hepatocarcinogenesis.
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Farombi E. Olatunde Korean Environmental Mutagen Society 2005 한국환경성돌연변이·발암원학회지 Vol.25 No.3
The genotoxic effect of antimalarial drugs amodiaquine (AQ), mefloquine (MQ) and halofantrine (HF) was investigated in.at liver cells using the alkaline comet assay. AQ, MQ and HF at concentrations between $0-1000{\mu}mol/L$ significantly increased DNA strand breaks of rat liver cells dose-dependently. The order of induction of strand breaks was AQ>MQ>HF. The rat liver cells exposed to AQ and HF (200 and 400 ${\mu}mol/L$) and treated with (Fpg) the bacterial DNA repair enzyme that recognizes oxidized purine showed greater DNA damage than those not treated with the enzyme, providing evidence that AQ and HF induced oxidation of purines. Such an effect was not observed when MQ was treated with the enzyme. Treatment of cells with catalase, an enzyme inactivating hydrogen peroxide, decreased significantly the extent of DNA damage induced by AQ, and HF but not the one induced by MQ. Similarly quercetin, an antioxidant flavonoid at $50{\mu}mol/L$ attenuated the extent of the formation of DNA strand breaks by both AQ and HE. Quercetin, however, did not modify the effects of MQ. These results indicate the genotoxicity of AQ, MQ and HF in rat liver cells. In addition, the results suggest that reactive oxygen species may be involved in the formation of DNA lesions induced by AQ and HF and that, free radical scavengers may elicit protective effects against genotoxicity of these antimalarial drugs.
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Erjun Wu,Olawale Olatunde Ayinde,Guangdong Zhou 대한토목학회 2022 KSCE Journal of Civil Engineering Vol.26 No.6
A major condition for the quality performance of connected-concrete layers is enough shear strength at the interface. Research shows that the interface shear behaviour is highly dependent on the texture of its interface. Although, several research on the effect of surface roughness on the interface shear behaviour of concrete to concrete connection using different interface patterns exists; however, there is scant literature on studies using quantitatively controlled interface texture, especially studies considering the roughness tooth geometrical parameters. In this study, seven different interface roughness geometries were designed and utilised as the study parameters for the interface shear behaviour, as well as the initial confining pressure. The double-sided shear test was used to determine the shear behaviour, failure mode, shear transfer mechanism, alongside the friction and cohesion values for all the studied interface types. The test results showed that both the interface roughness geometry and the magnitude of the confining pressure have a significant effect on the interfacial shear behaviour. Using different formations of the interface geometry provided a 15.4% difference in interfacial shear strength. For most of the interface geometries, interface cracking load increases linearly with the increase of initial confining pressure, while for the shear strength, the increase in confining pressure is more effective at lower pressure values. The friction and cohesion coefficients are influenced by the roughness tooth angle and tooth distribution.
KCI
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