75 research outputs found

    A Machine Learning Approach to Network Intrusion Detection System Using K Nearest Neighbor and Random Forest

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    The evolving area of cybersecurity presents a dynamic battlefield for cyber criminals and security experts. Intrusions have now become a major concern in the cyberspace. Different methods are employed in tackling these threats, but there has been a need now more than ever to updating the traditional methods from rudimentary approaches such as manually updated blacklists and whitelists. Another method involves manually creating rules, this is usually one of the most common methods to date. A lot of similar research that involves incorporating machine learning and artificial intelligence into both host and network-based intrusion systems recently. Doing this originally presented problems of low accuracy, but the growth in the area of machine learning over the last decade has led to vast improvements in machine learning algorithms and their requirements. This research applies k nearest neighbours with 10-fold cross validation and random forest machine learning algorithms to a network-based intrusion detection system in order to improve the accuracy of the intrusion detection system. This project focused on specific feature selection improve the increase the detection accuracy using the K-fold cross validation algorithm on the random forest algorithm on approximately 126,000 samples of the NSL-KDD dataset

    Antioxidant potential of African medicinal plants

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    Cellular damage or oxidative injury arising from free radicals or reactive oxygen species (ROS) now appears the fundamental mechanism underlying a number of human neurodegenerative disorders, diabetes, inflammation, viral infections, autoimmune pathologies and digestive system disorders. Free radical are generated through normal metabolism of drugs, environmental chemicals and other xenobiotics as well as endogenous chemicals, especially stress hormones (adrenalin and noradrenalin). Accumulated evidence suggests that ROS can be scavenged through chemoprevention utilizing natural antioxidant compounds present in foods and medicinal plants. Africa is blessed with enormous biodiversity resources, but plagued with several diseases, including those with ROS as the etiological factor. In this review, research on the antioxidant potential of medicinal plants of African origin between 1965 and September, 2004 is considered.African Journal of Biotechnology Vol. 4 (2), pp. 128-133, 200

    Bacterial reduction of N-oxides of tobacco- specific nitrosamines (TSNA)

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    1 Contrary to established metabolic pattern, a recent investigation of NNK metabolism produced in rat urine higher levels of 4-(methylnitrosamino)-1-(3-pyridyl)-1- butanone (NNK) and 4-(methylnitrosamino)-1-(3-pyri dyl)-1-butanol (NNAL) than their N-oxides, suggesting that reconversion of N-oxides could occur after urine formation. 2 To verify the possible role of bacteria in the reduction of NNK-N-oxide and NNAL-N-oxide to their respective parent compounds, NNK and NNAL, in smokers with urinary tract infection (UTI), the N-oxides were isolated from the urine of rats treated with 5-3HNNK and individually incubated at 37°C with ten bacterial species in sterile human urine under different pH regimens. After incubation with the bacteria, aliquots of culture media were analyzed by high pressure liquid chromatography (HPLC) with radiochemical detection. 3 Escherichia coli, Enterobacter cloacae, Klebsiella pneumoniae and Proteus mirabilis possessed varying capacity to regenerate NNK and NNAL from their N- oxides while others showed no detectable reductive capability within 24 h. 4 This result constitutes the first experimental evidence that in tobacco users with concomitant UTI, bacterial regeneration of the procarcinogenic NNK and NNAL from their N-oxides could occur in the bladder leading to increased carcinogen burden in these individuals

    Pharmacokinetics of biliary excretion of N-nitrosodiphenylamine (NDPA) in animals of different species

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    Pharmacokinetic investigations into the biliary excretion of N-nitrosodiphenylarnine given as an i.p. dose of 50 mg/kg were conducted and results compared in three animal species; rat, guinea pig and rabbit following bile duct (Simulation and collection of bile in vitro. The guinea pig excreted NDPA into bile fastest while the rabbit, which excreted it slowest, eliminated it fastest Both appearance and disappearance of the nitrosamine were comparatively slow in the rat NDPA elimination half-life values in the animal species were 510, 240 and 95 min respectively, while cumulative excretions amounted to 12, 3 and 0.3 percent. The toxicological implications of these species differences are highlighte

    In vitro trypanocidal effect of methanolic extract of some Nigerian savannah plants

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    Methanol extracts from twenty three plants harvested from the Savannah vegetation belt of Nigeria were analyzed in vitro for trypanocidal activity against Trypanosoma brucei brucei and Trypanosoma congolense at concentrations of 4 mg/ml, 0.4 mg/ml and 0.04 mg/ml. Extracts of Khaya senegalensis, Piliostigma reticulatum, Securidaca longepedunculata and Terminalia avicennoides were strongly trypanocidal to both organisms while extracts of Anchomanes difformis, Cassytha spp, Lannea kerstingii, Parkia clappertioniana, Striga spp, Adansonia digitata and Prosopis africana were trypanocidal to either T. brucei brucei or T. congolense. These findings provide evidence of the effects of some plants in the traditional management of trypanosomiasis. Key words: Savannah, medicinal plants, trypanocidal effects, trypanosomiasis, trypanosome, in vitro model. African Journal of Biotechnology Vol.2(9) 2003: 317-32

    HYPOGLYCAEMIC ACTIVITY OF NAUCLEA LATIFOLIA SM. (RUBIACEAE) IN EXPERIMENTAL ANIMALS.

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    Aqueous, ethanolic and hexane extracts of the leaves of Nauclea latifolia (Rubiaceae) were assessed for their fasting blood glucose lowering effect in normoglycaemic and streptozotocin – diabetic rats. Wistar strain albino rats were given different doses of the extracts after 18 hrs fast and their blood glucose measured at 0,1,2,4 and 6 hours after treatment. The aqueous and ethanolic extracts significantly lowered the fasting blood glucose levels of the STZ–diabetic rats in a dose–dependent manner. The highest dose administered (400mg/kg) lowered the fasting blood glucose of the diabetic rats by 31.7% (aqueous) and 36.1% (ethanolic) extracts. The aqueous extract did not significantly lower the glucose levels of normoglycaemic rats (maximum 6.6%), nor was any significant decrease seen in the rats administered with the hexane (maximum of 4.0% for normoglycaemic and 2.4% for diabetics) extract. The hypoglycaemic and antihyperglycaemic potentials of the aqueous and ethanolic extracts were comparable to that of glibenclamide (1mg/kg).These results further support the traditional use of the plant in the treatment of diabetes mellitus

    Potential of endogenous formation of volatile nitrosamines from Nigerian vegetables and spices

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    Nitrosatability of dried Nigerian vegetables and spices was investigated under simulated gastric conditions. N-Nitroso-dimethylamine (NDMA) was the only volatile nitrosamine found above the preformed level except in ugwu where N-nitroso-piperidine (2.3 ppb) was also detected. The lowest NDMA value of 0.4 ppb was found in bitterleaf while onions had the highest level (14.7 ppb) of nitrosation. The results suggest that, under endogenous conditions, nitrosation of these foodstuffs could be an important contributory factor in cancer aetiolog

    A cocrystal of 3α-hy­droxy­tirucalla-8,24-dien-21-oic acid and 3β-fluoro­tirucalla-7,24-dien-21-oic acid (0.897:0.103)

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    The title compound, 0.897C30H48O3.0.103C30H47O2F is a co-crystal of two triterpenes isolated from the resin of Canarium schweinfurthiiand Engl. Both triterpenes consists of four trans-fused rings having chair/half-chair/half-chair and envelope conformations. The mol­ecular conformations are stabilized by intra­molecular C—H⋯O hydrogen bonds, forming rings of S(7) graph-set motif. In the crystal, mol­ecules are linked by inter­molecular O—H⋯O and C—H⋯O inter­actions, forming sheets parallel to (001). All atoms. excepting the axially-oriented hydroxyl group in the major component and the equatorially-oriented fluorine atom in the minor component, are overlapping

    3α-Hy­droxy­tirucalla-8,24-dien-21-oic acid

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    The title compound, C30H48O3, a triterpene isolated from the resin of canarium schweinfurthiiand, is an isomer of the previously reported triterpene 3α-hy­droxy­tirucalla-7,24-dien-21-oic acid [Mora et al. (2001 ▶). Acta Cryst. C57, 638–640], which crystallizes in the same trigonal space group. The title mol­ecule consists of four fused rings having chair, half-chair, half-chair and envelope conformations for rings A, B, C and D, respectively (steroid labelling). An intra­molecular C—H⋯O hydrogen bond generates an S(7) ring. In the crystal, mol­ecules are linked by O—H⋯O and C—H⋯O inter­actions, forming (001) sheets

    Preformed volatile nitrosamines in some Nigerian foodstuffs

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    Some common Nigerian foodstuffs were assessed for their content of preformed volatile nitrosamine by chemiluminescence detection following gas chromatographic separation. Nitrosodimethylamine levels of between 0.4 and 4.6 ppb were detected in 75% of the samples analysed. The highest value was found in Brassica oleraceae, while Vernonia amygdalina contained the lowest detectable level. These data suggest that Nigerians may be exposed to chronic but very low levels of carcinogenic nitrosamines in their food
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