667 research outputs found

    Phenotypic screening of cowpea (Vigna unguiculata (L.) Walp) genotypes for resistance to cowpea viral diseases

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    Viruses are a major constraint to cowpea production in sub-Saharan Africa. Host plant resistance is the most effective and reliable method of managing viral diseases. In order to identify the source of resistance or tolerance, 38 cowpea genotypes were screened for virus infection under field conditions during the 2016 wet and dry seasons. The experiment was laid out in a randomized complete block design with four replications in both seasons. Disease severity was assessed fortnightly based on disease symptom using 1-5 visual scale (1=symptomless, and 5= very severe symptom). The cowpea genotypes exhibited varying reactions to viral infections with mean disease incidence ranging from 17.7% in the fourth week to 29.2% in the eighth week for the wet season and from 34.4% to 53.1% for the fourth and eighth week, respectively in the dry season. Symptoms observed were leaf mosaic (86.7%), leaf mottling (86.7%), chlorotic spots (34.2%), vein clearing (28.9%), leaf curl (26.3%), necrotic lesions (15.8%) and stunting (10.5%). Symptom severity in the rainy season ranged from symptomless (severity score of 1) in IT10K-819-4 and IT07K-297-13 to moderate symptom (severity score of 2.9) in Apagbaala. However, in the dry season, the symptom severity score ranged from 1.11 (mild symptom) in Marfo Tuya to a score of 2.4 (moderate symptom) in IT07K-298-9, thus demonstrating a significant genotype x season interaction effect. Incidence and severity were significantly higher in the dry season than in the rainy season. There was a strong positive correlation between the disease incidence and disease severity as well as AUDPC and no correlation between the cowpea incidence and the seed yield and plant height in the wet season. There was a negative correlation between the incidence and plant height in the dry season. Six genotypes (IT07-210-1-1, IT07K-297-13, IT08K-193- 14, IT09-456, IT10K-817-3 and IT10K-819-4) exhibited mild symptoms and gave high yields in both seasons, thus demonstrating a stable G x E interaction effect. These disease resistant genotypes could be evaluated further before release to farmers.Keywords: Area Under Disease Progress Curve, Host resistance, Vigna unguiculata, Viral disease

    The Use of Bauxite as an Arsenic Filter

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    AbstractArsenic (As) has the potential to negatively affect soils and groundwater quality, and cause several public health challenges. It is usually concentrated and released during metal mining of ores that contains arsenic-bearing minerals. Remediation strategies are in place to avoid pollution. In this study, bauxite from Awaso, Ghana, was characterised, and its ability to sequester As was tested under varying conditions of temperature, Eh and pH. The study showed that the best particle size in the range utilised was 80% passing 2 mm as it allowed easy percolation, and As removal was about 95%. The reaction is a favourable pseudo-second order reaction that is spontaneous and thermodynamically stable and compares well with the Langmuir Sorption Isotherm. About 80% sorption was achieved within 20 minutes of contact with low desorption rate of less than 1.8%. The study thus concludes that bauxite is a good filter for arsenic. Keywords: Arsenic, Bauxite, Filter, Sorption, Isother

    Urinary Lysosomal Enzyme Activities and Albuminuria in Ghanaian Patients with Type 2 Diabetes Mellitus.

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    Renal tubular lysosomal enzyme activities like alanine aminopeptidase (AAP) and N-acetyl-β-D-glucosaminidase (NAG) have been shown to increase in patients developing diabetic nephropathy and nephrosclerosis. This study aimed to determine the activities of N-acetyl-β-D-glucosaminidase and alanine aminopeptidase and albumin concentration in urine samples of patients with type 2 diabetes. One hundred and thirty (65 type 2 diabetic and 65 nondiabetic) subjects participated in this study. Blood samples were drawn for measurements of fasting blood glucose, albumin (Alb), lipids, and creatinine (Cr). Early morning spot urine samples were also collected for activities of alanine aminopeptidase (AAP), N-acetyl-β-D-glucosaminidase (NAG), and concentration of albumin (U-Alb) and creatinine (U-Cr). Both NAG/Cr and AAP/Cr were significantly increased in diabetic subjects compared to controls (p < 0.001). There was positive correlation between NAG/Cr and Alb/Cr (r = 0.49, p < 0.001) and between NAG/Cr and serum creatinine (r = 0.441, p < 0.001). A negative correlation was found between NAG/Cr and eGFR (r = -0.432, p < 0.05). 9.3% and 12% of diabetics with normoalbuminuria had elevated levels of AAP/Cr and NAG/Cr, respectively. We conclude that measuring the urinary enzymes activities (NAG/Cr and AAP/Cr) could be useful as a biomarker of early renal involvement in diabetic complications

    Callus induction and plant regeneration via leaf segments of three accessions of African rice (Oryza glaberrimaStued.)

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    A study conducted with the aim of developing a protocol for callus induction and plantlet regeneration in vitro from leaf segments of three accessions of African rice (O. glaberrimaSteud.) indigenous to Ghana. Leaf segments of the accessions namely, Guame, N/4 and SARI 1 were assessed for callus induction and plantlet regeneration ability on different concentrations of plant growth regulators, incorporated into Murashige and Skoog, (1962) (MS) basal medium. Frequency of callus induction which was achieved on MS medium supplemented with (0-10) mg/l 2,4-D differed significantly (p≤0.05) among the accessions, as well as among the levels of 2,4-dichlorophenoxyacetic acid (2,4-D) tested. Highest callus induction frequency was exhibited at a concentration of 6 mg/l 2,4-D for all three accessions.Sub-culturing of callus on regeneration medium, which consisted of MS supplemented with (1:0-5) mg/l NAA:BAP resulted in no plantlet regeneration in all tested accessions. Instead, prolific root formation was observed

    Mineral composition and assessment of human ingestion risk of twelve accessions of Moringa oleifera Lam

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    Increasing consumption of moringa leaf powder in Ghana is boosted by popular claims that the plant contains a rich array of minerals, vitamins and other protective substances. However, the safe doses of this product among gender classes and vulnerable groups are unknown. This knowledge gap demands an analysis of the mineral composition of the product and estimation of the risk (hazard) potential associated with the ingestion of dried leaf samples of the moringa plant. Mineral composition (Na, Mg, P, K, Ca, Mn, Cr, Fe, Cu and Zn) of dried leaf samples of twelve accessions of Moringa oleifera Lam. was determined using the Atomic Absorption Spectrometry aided by a fast sequential Atomic Absorption Spectrometer. Results of the study indicate that the samples showed variation with respect to macro and micro minerals content and that dried leaf powder of moringa can serve as an excellent source of minerals. Additionally, an estimation of hazard exposure calculated as hazard index presented overall indices of 0.0866 and 0.0443 for males and females respectively. Even though the values (0.076-0.097; 0.038-0.051) obtained from the samples are within safe limits, it is essential that consumption of moringa leaf powder is done on sound advice from a nutritionist since crucial factors such as gender, age, health status and exposure time contribute to individual dose needs and influence mineral toxicity

    A predictive integrated framework based on the radial basis function for the modelling of the flow of pharmaceutical powders

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    This study presents a modelling framework to predict the flowability of various commonly used pharmaceutical powders and their blends. The flowability models were trained and validated on 86 samples including single components and binary mixtures. Two modelling paradigms based on artificial intelligence (AI) namely, a radial basis function (RBF) and an integrated network were employed to model the flowability represented by the flow function coefficient (FFC) and the bulk density (RHOB). Both approaches were utilized to map the input parameters (i.e. particle size, shape descriptors and material type) to the flow properties. The input parameters of the blends were determined from the particle size, shape and material type properties of the single components. The results clearly indicated that the integrated network outperformed the single RBF network in terms of the predictive performance and the generalization capabilities. For the integrated network, the coefficient of determination of the testing data set (not used for training the model) for FFC was R2=0.93, reflecting an acceptable predictive power of this model. Since the flowability of the blends can be predicted from single component size and shape descriptors, the integrated network can assist formulators in selecting excipients and their blend concentrations to improve flowability with minimal experimental effort and material resulting in the (i) minimization of the time required, (ii) exploration and examination of the design space, and (iii) minimization of material waste

    Sphingolipid serum profiling in vitamin D deficient and dyslipidemic obese dimorphic adults

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    Recent studies on Saudi Arabians indicate a prevalence of dyslipidemia and vitamin D deficiency (25(OH)D) in both normal weight and obese subjects. In the present study the sphingolipid pattern was investigated in 23 normolipidemic normal weight (NW), 46 vitamin D deficient dyslipidemic normal weight (-vitDNW) and 60 vitamin D deficient dyslipidemic obese (-vitDO) men and women by HPTLC-primuline profiling and LC-MS analyses. Results indicate higher levels of total ceramide (Cer) and dihydroceramide (dhCers C18\u201322) and lower levels of total sphingomyelins (SMs) and dihydrosphingomyelin (dhSM) not only in -vitDO subjects compared to NW, but also in \u2013vitDNW individuals. A dependency on body mass index (BMI) was observed analyzing specific Cer acyl chains levels. Lower levels of C20 and 24 were observed in men and C24.2 in women, respectively. Furthermore, LC-MS analyses display dimorphic changes in NW, -vitDNW and \u2013vitDO subjects. In conclusion, LC-MS data identify the independency of the axis high Cers, dhCers and SMs from obesity per se. Furthermore, it indicates that long chains Cers levels are specific target of weight gain and that circulating Cer and SM levels are linked to sexual dimorphism status and can contribute to predict obese related co-morbidities in men and women

    Impact of irrigation scheduling practices on pesticide leaching at a regional level

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    A modelling approach was used to evaluate the scheduling practices of local farmers and two other irrigation scheduling practices for their potential impact on groundwater pollution in Doña Ana County, New Mexico, USA. The irrigation scheduling practices were: tensiometer-based with the tensiometers placed at 50 or 75% of the root-zone depth and irrigations started when tensiometer readings reached 6 kPa for sandy soils, 23 kPa for sandy loam soils, 44 kPa for loamy soils, and 74 kPa for clay loam soils; and at 50% plant available water depletion (PAWD) level regardless of soil type. The objective was to use irrigation scheduling model IRRSCHM, a volume balance, mixing-cell, type irrigation scheduling and pesticide transport model, to assess and compare the impact of different irrigation scheduling practices on cyanazine and metolachlor concentrations at 180 cm below the soil surface during a 30-year cropping sequence. The region was divided into different soil textural classes to facilitate rapid estimation of soil parameters needed for the model. Very low pesticide concentrations were predicted at 180 cm below the soil surface. However, the predicted pesticide concentrations increased as soil sand fractions increased, regardless of the irrigation scheduling practice. The tensiometer based irrigation scheduling resulted in the highest pesticide concentrations. The lowest concentrations were predicted under the farmer's practices due to deficit irrigation. Dual concentrations at 180 cm depth of the sandy soil class were ~20 times less than the Health Advisory Level under the tensiometer-based irrigation scheduling practices, while the farmer's practices resulted in metolachlor concentrations ~625 times less than the Health Advisory Level. Similarly, the predicted cyanazine concentration in sandy soil class was 3125 times less than the Health Advisory Level under the tensiometer-based irrigation scheduling and ~416 000 times less than the Health Advisory Level under farmer's practices. Simulation results suggested that current farmer's practices do not pose a threat to the area's groundwater quality and result in a 15-40% leaching fraction depending on soil type. Tensiometer-based irrigation scheduling was similar to scheduling irrigations at 50% plant available water depletion and resulted in a 35-50% leaching fraction depending on soil type as long as the tensiometer was placed in the proper root zone depth. The model's calculated leaching fractions using farmer's practices were similar to measured leaching fractions in Doña Ana County, giving credibility to the use of simulation models for assessing and comparing the potential impact of different irrigation scheduling practices on environmental quality at a regional level

    A STUDY ON THE SHORELINE CHANGES AND LAND USE/LAND COVER ALONG THE KETA COASTAL ZONE

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    The Keta Municipality has undergone a rapid increase in population due to economic and commercial activities. This led to the municipal’s coastal and shoreline zone being faced with severe environmental challenges throughout the years. The goal of the study was to evaluate Keta’s shoreline changes and the coastal Land Use Land Cover (LULC) using multi-temporal remote sensing datasets. These datasets were subjected to the following image processing techniques such as image enhancement, image classification and, shoreline extraction. The Digital Shoreline Analysis System (DSAS), a plugin tool in ArcGIS was utilized to assess the rate of shoreline changes (i.e., erosion or accretion) from 2000 to 2020. These were achieved based on the following statistical methods used; Linear Regression Rate (LRR), Net Shoreline Movement (NSM), and End Point Rate (EPR). The LULC analysis indicated that built-up areas and water bodies have increased rapidly from 14.71–18.43%, and 47.68–50.46% respectively from 2000 to 2021. In terms of the shoreline changes, LRR showed a mean of −0.95m/year with 68.22% faced with erosion and accretion of 31.78%. The EPR and NSM revealed a mean shoreline change of −1.19m/year and −26.3/period respectively from 2000 to 2021. The EPR and NSM results both revealed that 69.24% experienced erosion and 30.76% accretion, indicating the prevalence of erosion at the shoreline. This research is to contribute to both the development of Keta’s shoreline protection and management measures as well as sustainable land use planning. Also, aids in achieving most of the Sustainable Development Goals in the municipal
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