An Adaptive Rank Aggregation-Based Ensemble Multi-Filter Feature Selection Method in Software Defect Prediction.

Feature selection is known to be an applicable solution to address the problem of high dimensionality in software defect prediction (SDP). However, choosing an appropriate filter feature selection (FFS) method that will generate and guarantee optimal features in SDP is an open research issue, known as the filter rank selection problem. As a solution, the combination of multiple filter methods can alleviate the filter rank selection problem. In this study, a novel adaptive rank aggregation-based ensemble multi-filter feature selection (AREMFFS) method is proposed to resolve high dimensionality and filter rank selection problems in SDP. Specifically, the proposed AREMFFS method is based on assessing and combining the strengths of individual FFS methods by aggregating multiple rank lists in the generation and subsequent selection of top-ranked features to be used in the SDP process. The efficacy of the proposed AREMFFS method is evaluated with decision tree (DT) and naïve Bayes (NB) models on defect datasets from different repositories with diverse defect granularities. Findings from the experimental results indicated the superiority of AREMFFS over other baseline FFS methods that were evaluated, existing rank aggregation based multi-filter FS methods, and variants of AREMFFS as developed in this study. That is, the proposed AREMFFS method not only had a superior effect on prediction performances of SDP models but also outperformed baseline FS methods and existing rank aggregation based multi-filter FS methods. Therefore, this study recommends the combination of multiple FFS methods to utilize the strength of respective FFS methods and take advantage of filter-filter relationships in selecting optimal features for SDP processes.

Toxicological study of aqueous-methanol solvent fraction of methanol extract of Dacryodes edulis leaves.

Dacryodes edulis (G. Don) H.J. Lam) is the most popular species under the genus Dacryodes. It is well known for its nutritional and ethno-medicinal uses in South-eastern and South-western Nigeria. This study was aimed to evaluate the toxicity of the aqueous-methanol fraction of crude methanol extract of Dacryodes edulis leaves (AMDE). The test rats were randomized to groups of single oral treatment of AMDE (10-5000 mg/kgbw) for the acute toxicity study. They were monitored for obvious signs of behavioural change and mortality. For the subacute toxicity study, the rats were randomized to three daily treatment groups (of 200, 400 and 600 mg/kgbw of AMDE) for 28 days. The fourth group (control) received 2.5 %v/v DMSO. At the end of the experiment, blood samples were collected for hematology and clinical chemistry evaluation. The histopathology of the livers and kidneys were assessed using the excised organs. The cytotoxicity and genotoxicity of AMDE were also evaluated using Allium cepa model. The result showed that acute administration of AMDE, up to a dose of 5000 mg/kgbw did not result in mortality of the test rats. The observed median lethal dose (LD50) was greater than 5000 mg/kgbw. The subacute oral administration of AMDE for 28 days showed no significant (p > 0.05) effect on liver function, kidney function indices, organ - body weight ratio, but significantly (p < 0.05) decreased erythrocytic indices: red blood cells, haematocrit, and haemoglobin at 600 mg/kgbw. The Allium cepa assay revealed a non-significant reduction in mitotic index and low chromosomal aberrations of the treated groups. In conclusion, the aqueous-methanol solvent fraction of methanol extract of Dacryodes edulis leaves, AMDE is relatively safe. However, there are strong indications that it may contain compounds that are cytotoxic and reduces erythrocytic indices including red blood cells at high doses. Thus, adequate care should be taken in dosing and administering the extract to avert anaemic condition.

Insecticide Resistance Profile of Anopheles gambiae Mosquitoes: A Study of a Residential and Industrial Breeding Sites in Kano Metropolis, Nigeria.

Monitoring and understanding the trend and dynamics of insecticide resistance is very key to devising efficient control strategies. This study was carried out to characterize the mosquito population, its insecticide resistance profile, and the physicochemical properties of their breeding sites in Sharada and Wailari of Kano State, Nigeria. Six breeding sites from the 2 study areas were sampled and their physicochemical parameters determined. Mosquito larvae were sampled from the sites and reared to adult. The emergent adults were morphologically and molecularly identified to species level. The World Health Organization (WHO) susceptibility assay was carried out on the adult mosquitoes using different classes of insecticides in WHO discriminating concentrations. kdr-mutation was detected by polymerase chain reaction (PCR)-based method using the permethrin (pyrethroid) resistant and susceptible adult mosquitoes. Most of the determined physicochemical parameters were significantly higher in the industrial area, Sharada. Morphologically, the mosquitoes from the 2 sites were identified as Anopheles gambiae and 100% of the randomly sampled population were found to be Anopheles coluzzii by PCR-based molecular technique. The WHO susceptible assay revealed a graded level of resistance to bendiocarb, dichlorodiphenyltrichloroethane (DDT), and permethrin with mortalities of 78.36%, 75.74%; 43.44%, 56.96%; and 37.50%, 37.50% in both Sharada and Wailari, respectively. Pre-exposure to piperonyl butoxide (PBO) resulted in a significant but minor recovery of susceptibility to permethrin. The kdr mutation frequency was higher in Sharada (45.71%) relative to Wailari (31.43%). Higher kdr mutation frequency was also observed in the resistant population (48.56%) relative to the susceptible (28.54%). The kdr mutation frequency was weakly associated with the resistance status (odds ratio [OR]: 5.9, χ2:3.58, P = .058) and the breeding sites (OR: 3.46, χ2:2.90, P = .088). In conclusion, the study revealed a highly pyrethroid-resistant A coluzzii population with low PBO recovery rate. Furthermore, the data suggested the involvement of kdr mutation, detoxification enzyme, and possibly abiotic factors of the breeding sites.

In vitro and in vivo anti-diabetic and anti-oxidant activities of methanolic leaf extracts of Ocimum canum.

BACKGROUND: Diabetes is a metabolic disorder with a highly complex, multifaceted and intricate etiologies and thus may require management options that proffers multimodal mechanism of action. This present study evaluated the antidiabetic and antioxidant potential of the methanolic extract/fractions of leaves of Ocimum canum. METHODS: The antidiabetic potential was evaluated and using STZ-induced diabetic Wistar rat model (in vivo) and inhibition of α-amylase and α-glucosidase activity (in vitro). Antioxidant activity was assessed in vitro by free radical scavenging and reducing power assays and in vivo via monitoring SOD and CAT activities; GSH and MDA levels. RESULTS: The total phenolic content (221.0±3.0 mg catechol/g of sample) and tannins (146.0±4.0 mg tannic acid/g of sample) of the crude extract; and flavonoid of the aqueous-methanol fraction (216.0.0±1.0 mg of rutin/g of sample) were found to be significantly higher relative to others. The crude extract and the aqueous-methanol fraction exhibited a significantly (p<0.05) higher percentage reduction in fasting blood glucose and a concomitant increase in serum insulin level relative to the diabetic control group. The highest radical scavenging activity and reducing power were observed in the aqueous-methanol fraction. The aqueous-methanol solvent fraction also significantly reversed the alterations in oxidative stress markers occasioned by the diabetic condition. CONCLUSION: In conclusion, the result of the present study has demonstrated evidently that extracts of Ocimum canum leaves ameliorates hyperglycemia and the associated oxidative stress in STZ-induced rats.

Methanol-Extract/Fractions of Dacryodes edulis Leaves Ameliorate Hyperglycemia and Associated Oxidative Stress in Streptozotocin-Induced Diabetic Wistar Rats.

The present study evaluated the antidiabetic and antioxidant potential of the methanolic extract/solvent fractions of the leaves of Dacryodes edulis using a streptozotocin (STZ)-induced diabetic Albino Wistar rat model. The fasting blood glucose/insulin levels and inhibition of α-amylase and α-glucosidase were determined. Antioxidant activity was assessed in vitro by 2,2-diphenyl-1-picrylhydrazyl, hydroxyl, superoxide scavenging, reducing power, and total antioxidant capacity assays and in vivo by monitoring catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) activities and reduced glutathione (GSH) and malondialdehyde (MDA) levels. The aqueous-methanol fraction exhibited the highest and significant ( P < .05) reduction in fasting blood glucose (FBG; 54.03%) with a concomitant inhibition of α-amylase and α-glucosidase activities. The ethyl acetate fraction also exhibited a significant ( P < .05) reduction in FBG and an increase in insulin levels in the treated diabetic Wistar rats. A significantly ( P < .05) higher reducing power and radical scavenging activity was observed in the aqueous-methanol and ethyl acetate fractions. The aqueous-methanol and ethyl acetate fractions also significantly ( P < .05) reversed the alterations in oxidative stress markers (GSH, MDA, CAT, and SOD) observed in the diabetic control group. In conclusion, the study demonstrated that the methanol extract of Dacryodes edulis ameliorates hyperglycemia and the associated oxidative stress in STZ-induced diabetic Wistar rats. These observed activities are largely due to the compounds that partitions into the aqueous-methanol (55:45) solvent fraction. This provides scientific evidence for the use of this plant extract in folk medicine and also a baseline data for its further characterization. Further work should be carried out to characterize the aqueous-methanol solvent fractions for the active compounds.