ghanaopendata/ghanaian-research-english huggingface dataset:
A comparative study of the toxicity of some plant extracts and some xenobiotic pesticides towards selected insect species: laboratory bioassays and field validation.

The toxicity of Turraeanthus africana stem bark and the leaf of Mitragyna stipulosa were investigated for their insecticidal properties and use as alternative pesticides. Phytochemical screening indicated that the petroleum ether (pet ether) extract of the Turraeanthus africana contained mainly terpenoids/ steroids. The methanol extract of Turraeanthus africana contained saponins, steroids/terpenoids, tannins, and alkaloids. The pet ether extract of Mitragyna stipulosa contained steroids/terpenoids and cardeolides (cardiac glycosides) whiles the ethanol extract of M. stipulosa (MSE) contained saponins, steroids/terpenoids, tannins, alkaloids cardeolides and flavonoids. The crude ether extract of T. africana (AVP) was analysed on a glass column constituting 3% OV- 17. Forty-one components were resolved with the major component constituting 21.4% of the crude and having a retention time of 80.58 relative to hexane. Isothermal runs of the column-eluted fractions of (AVP) at an oven temperature of 255 °C indicated a relation between the percentage composition of compound with kovats index of 3600 and their brine shrimps lethality. The second fraction was having the highest lethality of LC50 of 1.21 μg/ml and a percentage composition of 55.23%. AVP crude extract (yield 5.3%) was found to be active against brine shrimps, Oreochromis niloticus and storage pests i.e. Sitophilus zeamais and calusobruchus maculatus with LC50 values of 39.56 μg/ml, 2.75 μg/ml, 292.28 μg/ml, and 229.67 μg/ml respectively. LC50 of pirimiphos methyl on S. zeamais and C. maculatus was 0.002 μg/ml and 7.11 μg/ml respectively. The pet ether extract of M. slipulosa (MSP) was observed to be active to Balanogastris kolae with LC50 of 1225.56 μg/m whiles the lethality to B. kolae by Gammalin 20 had LC50 90.85 μg/ml. The 24hr brine shrimp lethality of MSP was 15.31 μg/ml. Simulation of the laboratory bioassays on field trials revealed that, AVP applied at a concentration of 0.60%, was effective in the control of S. zeamais and C. maculatus over a 2 month and 3 month period respectively. 0.60% concentration of the methanol extract of T. africana deterred oviposition in C. maculatus sufficiently and controlled C. maculatus over a 3 month period but was not effective against S. zeamais.

Source: KNUST
A comparative study of typhidot and widal tests for the detection and diagnosis of typhoid fever in patients

Typhoid fever continues to be a public health issue in most developing countries. In Ghana, Typhoid Fever ranks among the first twenty causes of outpatient illness. Among the numerous challenges in addressing the disease burden of Typhoid is the quest to secure a more reliable and standardized laboratory diagnoses of Salmonella infections to be able to win the surveillance battle on Typhoid fever. The purpose of this study was to compare the specificity and sensitivity of Typhidot and Widal serological tests for the detection of typhoid fever in the Bekwai Municipality. A prospective hospital based longitudinal study was conducted by gathering samples of 292 potential patients who showed features of Typhoid infection. Adopting a purposive sampling technique, patients who met the inclusion criteria were conveniently sampled and enrolled. Blood culture was used as the standard protocol after which sensitivity, specificity and positive predictive values were compared between Typhidot and Widal serological test kits. Data was analyzed using SPSS version 20 to process after which results were presented descriptively. Chi square test of association was performed for categorical variables .The study on 292 individuals recorded sensitivity of widal (95%) and typhidot (85.8%) with the specificity of widal (54.0%) and Typhidot (90.1%). This observation indicates Widal test is much more sensitive than the typhidot in the study area. The study established that both tests could be equally, sensitive and specific in diagnosing typhoid since they both had an equal accuracy (98.0) making them suitable for rapid diagnosis. The study found high detection of S. typhi by blood culture diagnosis, with S. paratyphi and S. typhimurun occurring least. This study has implication for further study to be carried out for confirmatory purposes as well as to determine prevalence of infection and antigenic variants that were not captured in the present study.

Source: KNUST
A comparative study of Typhidot and Widal tests for the detection and diagnosis of Typhoid fever in patients.

Typhoid fever continues to be a public health issue in most developing countries. In Ghana, Typhoid Fever ranks among the first twenty causes of outpatient illness. Among the numerous challenges in addressing the disease burden of Typhoid is the quest to secure a more reliable and standardized laboratory diagnoses of Salmonella infections to be able to win the surveillance battle on Typhoid fever. The purpose of this study was to compare the specificity and sensitivity of Typhidot and Widal serological tests for the detection of typhoid fever in the Bekwai Municipality. A prospective hospital based longitudinal study was conducted by gathering samples of 292 potential patients who showed features of Typhoid infection. Adopting a purposive sampling technique, patients who met the inclusion criteria were conveniently sampled and enrolled. Blood culture was used as the standard protocol after which sensitivity, specificity and positive predictive values were compared between Typhidot and Widal serological test kits. Data was analyzed using SPSS version 20 to process after which results were presented descriptively. Chi square test of association was performed for categorical variables .The study on 292 individuals recorded sensitivity of widal (95%) and typhidot (85.8%) with the specificity of widal (54.0%) and Typhidot (90.1%). This observation indicates Widal test is much more sensitive than the typhidot in the study area. The study established that both tests could be equally, sensitive and specific in diagnosing typhoid since they both had an equal accuracy (98.0) making them suitable for rapid diagnosis. The study found high detection of S. typhi by blood culture diagnosis, with S. paratyphi and S. typhimurun occurring least. This study has implication for further study to be carried out for confirmatory purposes as well as to determine prevalence of infection and antigenic variants that were not captured in the present study.

Source: KNUST
A comparative studyof the interactionof nickel, titanium,palladium, andgold metalswith single-walled carbonnanotubes:A DFT approach

Interactions between transition metal atoms, nickel, titanium, palladium and gold and (3,3), (4,2), (6,0) and(5,1) carbon nanotubes were studied using first principles calculations. The Fermi energy levels of the carbonnanotubesstudiedwerefoundtoincreaseduringinteractionswiththetransitionmetalatoms.Amongstthefourmetals, gold atom was found to have an enhanced interaction with the nanotubes transforming from semi-conductingtoaconductingtube.Titaniumwasalsofoundtoshowsimilarcharacteristicstogoldonlywhentheatomwasplacedinthemiddleofthecarbonnanotubes.Nickelandpalladiumatomsinteractionsdidnotaffectmuchtheelectronicpropertiesofthecarbonnanotubes,withsomeslightchangesintheelectronicpropertiesatsomespecificsitesofthenanotubes.Itisproposedfromthisstudythat,thecarbonnanotube-metalinteractionscould be used as a guide to shed light on the electronic properties of such materials which could become pro-mising engineering materialsand revolutionizethe electronic industry.

Source: KNUST
A Comparative Study on the Antimicrobial Activity of Natural and Artificial (Adulterated) Honey Produced in Some Localities in Ghana

The study measured and compared quality parameters such as pH, moisture content, ash content and hydrogen peroxide concentration of three types of honey from different localities in Ghana. Using the agar well diffusion, antimicrobial potential of natural honey from two different sources as well as an adulterated honey were determined against Staphylococcus aureus (ATCC 25923), Escherichia coli(ATCC 35218)and Klebsiella pneumonia (ATCC 27736). The results of the physico-chemical properties showed the following range of values; pH of (3.68– 4.49), moisture content (17.20 – 22.42%) and ash content (0.09 – 0.48%). The moisture content of the adulterated samples at 25% and 50% concentration in all cases exceeded the recommended 21%of good quality honey. The findings also indicated that, natural honey (Koforidua and Berekum) has a higher antimicrobial activity against all the bacteria compared to the adulterated honey. The susceptibility of Escherichia coli, to the honey treatment, was significantly different (p=0.0383) from S. aureus and K. pneumoniae. However, when the susceptibility of S. aureus and K. pneumoniae, when compared was insignificant (p=0.6292).The adulteration of the honey could have caused some of the antibacterial factors in the honey to be lost or reduced to non-lethal amounts, hence losing it antimicrobial properties.

Source: KNUST
Comparative Study on the Properties of Yam (Dioscorea Rotundata) Varieties in Ghana: A Case Study in Asante Mampong

Four local varieties of Dioscorea rotundata namely Pona, Labreko, Asobayere and Muchumudu were compared by analyzing for their organoleptic, physicochemical and functional properties to ascertain whether these varieties have unique characteristics for particular food products. A survey was initially conducted in Asante Mampong (a yam farming community) and results revealed a high preference for Labreko in terms of eating quality (mealiness, taste and softness). This was confirmed in a sensory analysis test which revealed high scores for mealiness and taste for Labreko; hence Labreko may be promoted for export and local consumption. Significant differences existed in moisture, ash and carbohydrates. Muchumudu had the highest moisture content (74.43%) and may be used for mashed products such as yam pottage. Asobayere had the lowest moisture content (58.91%) and may be exploited for export because of its potential high keeping quality. Carbohydrate contents ranged from 34.24% (Asobayere) to 14.78% (Muchumudu). Mineral analysis showed that Pona was relatively high in iron (4.45 mg/100 g). High calcium (91.60 mg/100 g) and phosphorus (114.50 mg/100 g) contents were recorded in Muchumudu, which is reflective of its high ash content (3.46%). Thus, Muchumudu may be a good source of calcium and phosphorus for growing children. Asobayere had the highest starch yield (20.89%) and may be exploited for starch production. Flours and starches from the yam varieties showed similar trends in amylose contents, swelling power, water binding capacity and some pasting properties. For the starches, amylose content ranged from 27.48 to 31.55%; swelling power ranged from 10.57 to 12.48; solubility index ranged from 8.52 to 9.32% and water binding capacity ranged from 175.25 to 182.69%. There were significant differences (P<0.05) in the pasting properties of the starch samples. The pasting temperature ranged from 75.10 (Asobayere) to 77.30°C (Muchumudu). Labreko and Asobayere may also be used for foods that require shorter processing time such as instant foods because of their low pasting temperatures. The peak viscosity ranged from 614 (Pona) to 726 BU (Asobayere). Asobayere may thus be used for foods that require thick and cohesive paste, gel strength and elasticity. The final viscosity ranged from 385 (Pona) to 817 BU (Muchumudu). The breakdown viscosity ranged from 25 (Muchumudu) to 385 BU (Asobayere). Muchumudu may be used in products that require low viscosity and paste stability at low temperatures. Pasting properties of the flours also followed a similar trend. The results of the study show that Labreko, Asobayere and Muchumudu have unique characteristics which can be used as a basis for their promotion to increase the range of options for consumers on the local and export markets.

Source: KNUST
Comparative Total Phenolics and Antioxidant Activities of Xanthosoma colocasia, Solanum torvum and Allium ascalonicum L.

Fruits and vegetables are known to have free radical scavenging abilities due to the antioxidants in them and this gives them the ability to prevent diseases and sicknesses. This study was carried out to investigate the total phenolic content and free radical scavenging abilities of some selected vegetables and to determine their minimum inhibitory concentration (IC50). These vegetables include Solanum torvum, Xanthosoma colocasia, and Allium ascalonicum Linn. The total antioxidant capacity (TAC), total phenol content (TPC), ferric reducing antioxidant power (FRAP) and the DPPH scavenging assays of the methanolic extracts of samples were determined. The results for the total antioxidant capacity of the measured concentration (0.1-0.3 mg/mL) were 0.146 ± 0.00004, 0.102 ± 0.00006, and 0.085±0.00003 mg AAE/g respectively for Solanum torvum, Allium ascalonicum Linn and Xanthosoma colocasia. Total phenolic content values were 0.180±0.00015, 0.124±0.00008, and 0.102±0.00003 mg TAE/g for Solanum torvum, Allium ascalonicum Linn and Xanthosoma colocasia respectively. There was a perfect correlation between total antioxidant capacity (TAC) and total phenolic content (TPC) of the extracts with r2 =1 and p<0.001. Solanum torvum exhibited the highest ferric reducing antioxidant power with values ranging from 0.013919 to 0.1464 mg GAE/DW for the concentration range of 0.1–3 mg/mL. Solanum torvum, Allium ascalonicum and Xanthosoma colocasia had IC50 values of 1.0676, 1.5978, and 1.6753 mg GAE/DW respectively. Percentage scavenging ability were 78.60, 63.41 and 58.95 respectively for Solanum torvum, Allium ascalonicum L., and Xanthosoma colocasia at 3 mg/mL concentration. The results indicate that all the vegetables exhibit antioxidant capacities and Solanum torvum is a significant source of antioxidants.

Source: KNUST
Comparative study on face recognition techniques: Principal Component Analysis and Linear Discriminant Analysis

Face Recognition System employs a variety of feature extraction (projection) techniques which are grouped into Appearance-Based and Feature-Based. In a vast majority of the studies undertaken in the field of Face Recognition special attention is given to the Appearance-Based Methods which represent the dominant and most popular feature extraction technique used. Even though a number of comparative studies exist, researchers have not reached consensus within the scientific community regarding the relative ranking of the efficiency of the appearance-based methods (LDA, PCA etc) for face recognition task. This paper studied two appearance-based methods (LDA, PCA) separately with three (3) distance metrics (similarity measures) such as Euclidean distance, City Block & Cosine to ascertain which projection-metric combination was relatively more efficient in terms of time it takes to recognise a face. The study considered the effect of varying the image data size in a training database on all the projection-metric methods implemented. LDA-Cosine Distance Metric was consequently ascertained to be the most efficient when tested with two separate standard databases (AT & T Face Database and Indian Face Database). It was also concluded that LDA outperformed PCA.

Source: KNUST
Comparing Krasnoselskij and Mann Iterative Methods for Lipschitzian Generalized Pseudo-Contractive Operators in Hilbert Spaces

We introduce certain iterative methods (Krasnoselskij, Mann and Ishikawa) that ensure convergence to a fixed point for certain classes of operators that satisfy weak contractive type conditions, for which the Picard iteration guarantees no convergence. Some convergence theorems are stated and proved for these classes of operators. We finally compare the convergence rate of Krasnoselskij and Mann iterative methods known to converge to a fixed point of Lipschitzian generalized pseudo-contractive operators in Hilbert spaces.

Source: KNUST
Comparing the Effectiveness of Garlic (Allium sativum L.) and Hot Pepper (Capsicum frutescens L.) in the Management of the Major Pests of Cabbage Brassica oleracea (L.)

The use of chemical insecticides in crop production has resulted in increased food production in Africa, but their use has resulted in the destruction of beneficial organisms and development of resistance by some insects to the insecticides. The effectiveness of garlic Allium sativum and hot pepper, Capsicum frutescens in controlling the pests of cabbage, Brassica oleracea was evaluated. These botanicals were compared with a standard chemical insecticide Attack® (Emamectin benzoate). The experiment was conducted in a randomized complete block design, with 3 treatments and a control, each of which was replicated 3 times. Plutella xylostella, Brevicoryne brassicae, Hellula undalis and Trichoplusia ni were found on cabbage plants. Significantly fewer of them were found on the treated plants than the control plants. The use of the plant extracts resulted in a reduction in mortality ranging from 10.76% to 55.94%. Fewer natural enemies of B. brassicae were sampled on the insecticide-sprayed plots than the garlic and pepper-sprayed plots. The cost of protecting cabbage plants from insect infestation using Attack was higher than the botanicals. Garlic-treated plots recorded the highest cost: benefit ratio of 1:16 while Attack®-treated plots recorded the least of 1: 9.2. The control effects of the botanicals compared favourably with that of the chemical insecticides. Thus these botanicals can be used as substitutes to chemical insecticides.

Source: KNUST
Comparison of a Standardized Antimicrobial Susceptibility Disc Diffusion Method with Komfo Anokye Teaching Hospital’s Locally Adapted Method.

The clinical microbiology laboratory of the Komfo Anokye Teaching Hospital employs a locally adapted method for antimicrobial susceptibility testing. This method is a variant of the British Society for Antimicrobial Chemotherapy (BSAC) standardized disc diffusion method. Antimicrobial susceptibility testing of bacteria isolated at the Komfo Anokye Teaching Hospital (KATH) was performed using the BSAC method. A total of 200 bacterial isolates were cultured from nine different types of specimens. The sites of origin were urine 33%, blood 32%, sputum, pus, wound, ear and aspirated specimens 31.5%, urethral smear 1.5% and cerebrospinal fluid 1.0%. Gram-negative bacteria accounted for 183 (91.5%) isolates; the main species were Escherichia coli (34.5%), Klebsiella pneumoniae (18.5%), Pseudomonas aeruginosa (9.0%), Proteus mirabilis (3.5%), Salmonella typhi (7.0%) and coliforms (19.0%). Gram-positive bacteria contributed 17 (8.5%) of isolates with Staphylococcus aureus 6.5% being the most predominant followed by Streptococcus pneumoniae 2.0%. Escherichia coli showed 100% and 92% resistance to ampicillin and cefuroxime respectively with 36% being susceptible to cefotaxime. Amikacin resistance in Gram-negative bacilli was 18.7%. Staphylococcus aureus strains showed 36% resistance to oxacillin. Streptococcus pneumoniae isolates showed 100% resistance to oxacillin and also to ceftriaxone. Comparison of susceptibility results of both methods showed 49.1% and 35.8% agreement in susceptible and resistant results respectively. As much as 29.9%, 2.8% and 5.1% of susceptibility results of the locally adapted method were reported as very major, major and minor errors respectively against the BSAC. The study recommends that the locally adapted method be revised in relation to current standard practices.

Source: KNUST
Comparison of an UV-Spectrophotometric method and HPLC method for the assay of Co-trimoxazole preparations

Bacterial infections are prevalent in the country. Co-trimoxazole an antibacterial agent is effective against a large number of bacteria. This agent due to the low cost appears on the local market from various countries. It is important that a rapid, simple, reproducible and accurate method is designed for its analysis. Modem trends in drug analysis prefer the use of fast, reproducible, simple and convenient methods. An HPLC method for the quantification of cotrirnoxazole is described. The method involved dissolution of an amount of the powdered drug sample equivalent to 100mg sulphai.nethoxazole and 20mg trimethoprim in l00ml of ethanol and further dilution of the solution such that the final concentration of suiphainethoxazole and trimethoprirn was .40μg/ml and 8μg/ml respectively. Chromatographic separation was achieved on a Hypersil C-18 reversed phased column. Column cluate was monitored at 254nm using a UV detector. The isocratic form of elution was employed at a flow rate of 0.8mllminute and the column eluate monitored at a wavelength of 254nna and 0.5 AUFS. Chromatography was carried out at ambient temperature. Total chromatography time was approximately 7 minutes. Quantification was achieved using the method of internal calibration with procaine hydrochloride serving as internal standard. The method was used to analyze some brands of cotrirnoxazole on the local market and the results obtained compared statistically to an existing UV method. it was generally observed that the selected brands conformed to the BP specified quantities of active principle

Source: KNUST
Comparison of Change Detection Techniques in the Ejisu-Juaben District

Land cover/use change information has become important in the life of every nation due to its negative and positive effects. To be able to account for change a technique, which is convenient for the landscape in question has to be used to do the change analysis. The main objective of this study was to compare various change detection techniques for two dates and find out the optimum one suitable for the chosen study area, which is the Ejisu - Juaben district of the Ashanti region. The methods compared were image differencing, tasseled cap, principal component analysis (PCA), change vector analysis, normalized difference vegetative index (NDVI) and post classification. 1986 TM and 2007 ETM+ images were used for the analysis. The images underwent geometric and radiometric corrections before the data were processed to reveal change using the various techniques. The various techniques each showed its ability to depict change over the chosen duration. After assessing their accuracies using the error matrix NDVI came out to be the best with a Kappa of 0.5139. A land cover/use projection for 2020 was also attempted using Markov chain and cellular automata. This produced a land cover/use map showing the changes that might occur in the year 2020 if things continue the way they are without any monitoring and management of the various land covers. Keywords: Change detection, Land covers/use, post classification, Markov chain.

Source: KNUST