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Bacteriological safety of plastic-bagged sachet drinking water sold in Amassoma,Nigeria

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Asian Pacific Journal of Tropical Medicine 2010年第7期3卷 555-559页

作者： yakubu B Ngwai Adebukola A Sounyo Siyeofori M Fiabema Geoffrey A Agadah Tamunobelema o Ibeakuzie Microbiology Unit Nasarawa State UniversityP.M.B.1022KeffiNasarawa StateNigeria Department of Pharmaceutical Microbiology and Biotechnology Faculty of PharmacyNiger Delta UniversityWilberforce IslandP.M.B.071 YenagoaNigeria

objective:To evaluate the bacteriological safety of sachet water sold in Amassoma,a rural community in Bayelsa State,***:Six samples of each of the different sachet drinking water brands were bought at random from shop shelves,markets and street vendors and were studies for microbial indicators of safety and *** counts Were analyzed by one-way Analysis of Variance（ANoVA） and significance of differences was tested at 5% ***:Minimum and *** with regard to the sachet water samples investigated were（4.3±1.1）×106 CFU mL-1 and（8.2±1.0）×106 CFU mL-1 for heterotrophic plate counts;（0.9±0.3）×106 CFU mL-1 and（1.2±0.4）×106 CFU mL-1 for aerobic spore-former counts; （1.3±0.5）×103 CFU mL-1 and（2.5±0.8）×103 CFU mL-1 for total coliforms;（1.6±0.9）×103 CFU mL-1 and（9.5±11.2）×103 CFU mL-1 for thermotolerant *** spp but not Escherichia coli was present in all samples of the brands;non-coliform bacteria detected in some samples were Staphylococcus,Pseudomonas and Bacillus ***:The brands of sachet water sold（at the time of this study） in Amassoma did not meet the minimum acceptable standard for microbiologically safe drinking water as recommended by the World Health organization.

关键词： Water Sachet Safety Quality Bacteriological

Modeling, Steady-State Analysis of a SEPIC dc-dc Converter Based on Switching Function and Harmonic Balance Technique

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Journal of Power and Energy Engineering 2014年第4期2卷 704-711页

作者： Ajayi Samuel taiwo Joseph yakubu oricha Electrical and Computer Engineering Department Ahmadu Bello University Zaria Nigeria

The paper presents modeling approach of a Single Ended Primary Inductance Converter (SEPIC) system. The complete model derivation of the SEPIC converter system has been presented in different modes of operation. Steady state and small signal analysis was carried out on the converter dynamic equations using the method of Harmonic balance Technique. The steady state variables and their respective ripple quantities obtained were plotted against duty ratio D. The results obtained for a supply input voltage of 60 volts to the converter at a duty ratio of D = 0.8 , compares well with simulation results.

关键词： SEPIC Converter Switching Function Harmonic Balance Technique

Morphological and microsatellite DNA diversity of Nigerian indigenous sheep

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Journal of Animal Science and Biotechnology 2013年第1期4卷 18-33页

作者： Brilliant o Agaviezor Sunday o Peters Mufliat A Adefenwa Abdulmojeed yakubu olufunmilayo A Adebambo Michael o ozoje Christian oN Ikeobi Matthew Wheto oyeyemi o Ajayi Samuel A Amusan oludotun J Ekundayo Timothy M Sanni Moses okpeku Gbolabo o onasanya Marcos De Donato Babatunde M Ilori Kadir Kizilkaya Ikhide G Imumorin Department of Animal Breeding and Genetics University of Agriculture Department of Animal Science and Fisheries University of Port Harcourt Dept of Animal Science Cornell University Dept of Animal Science Berry College Department of Cell Biology and Genetics University of Lagos Department of Animal Science Nasarawa State University Dept of Livestock Production Niger Delta University Department of Animal Science Adnan Menderes University

Background： Sheep is important in the socio-economic lives of people around the world. It is estimated that more than half of our once common livestock breeds are now endangered. Since genetic characterization of Nigerian sheep is still lacking, we analyzed ten morphological traits on 402 animals and 15 microsatellite DNA markers in 384 animals of the 4 Nigerian sheep breeds to better understand genetic diversity for breeding management and germplasm conservation. Results： Morphological traits of Uda and Balami were significantly （P 〈 0.05） higher than Yankasa, which were both higher than West African Dwarf （WAD） sheep. Stepwise discriminant analysis showed tail length, rump height, chest girth, ear length and chest depth as the most discriminating variables for classification. Mahalanobis distances show the least differentiation between Uda and Balami and the largest between WAD and Balami sheep. While 93.3% of WAD sheep were correctly assigned to their source genetic group, 63.9% of Yankasa, 61.2% of Balami and 45.2% of Uda were classified correctly by nearest neighbour discriminant analysis. The overall high Polymorphism Information Content （PIC） of all microsatellite markers ranged from 0.751 to 0.927 supporting their use in genetic characterization. Expected heterozygosity was high for all loci （0.783 to 0.93）. Mean heterozygote deficiency across all populations （0.17] to 0.534） possibly indicate significant inbreeding （P 〈 0.05）. Mean values for FST, FIT and F^s statistics across all loci were 0.088, 0.394 and 0.336 respectively. Yankasa and Balami are the most closely related breeds （DA = 0.184） while WAD and Balami are the farthest apart breeds （DA-- 0.665）, which is coincident with distance based on morphological analysis and population structure assessed by STRUCTURE. Conclusions： These results suggest that within-breed genetic variation in Nigerian sheep is higher than between-breeds and may be a valuable tool for genetic improvement and conservation. The

关键词： Discriminant analysis Genetic distance Microsatellite DNA Morphological traits Nigerian sheep

Differential modulation of bradykinin-induced relaxation of endothelin-1 and phenylephrine contractions of rat aorta by antioxidants

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Acta Pharmacologica Sinica 2007年第10期28卷 1566-1572页

作者： ogechukwu ANoZIE Richonda RoSS Adebayo o oYEKAN Momoh A yakubu Vascular Biology UnitCenter for Cardiovascular Diseases College of Pharmacy and Health Sciences Texas Southern University Houston Texas 77004 USA

Aim:We tested the hypothesis that bradykinin （BK）-induced relaxation of phe-nylephrine （PE） and endothelin-1 （ET-1） contractions can be differentially modu-lated by reactive oxygen species （RoS）.Methods:Aortic rings isolated fromSprague-Dawley rats were used for the *** contribution of RoS to PE(1×10-9-1×10-5mol/L)-and ET-1 (1×10-10-1×10-8mol/L)-induced contractions andthe influence of RoS in BK (1×10-9-1×10-5mol/L) relaxation of PE (1×10-7mol/L) orET-1 (1×10-9mol/L)-induced tension was evaluated in the aorta in the presence orabsence of the following antioxidants:catalase （CAT,300 U/mL）,superoxidedismutase （SoD,300 U/mL）,and vitamin C (1×10-4mol/L).Results:Tension gen-erated by ET-1 (1×10-9mol/L) or PE (1×10-7mol/L) was differentially relaxed by BK(1×10-5mol/L),producing a maximal relaxation of 75%±5% and 35±4%,*** BK (1×10-5mol/L)-induced relaxation of PE (1×10-7mol/L) tension was signifi-cantly enhanced from 35%±4% （control） to 56%±9%,60%±5%,and 49%±6% bySoD,CAT,and vitamin C,respectively （Powever,the relaxation ofET-1 (1×10-9mol/L) tension was significantly attenuated from 75%±5% （control）to 37%±9%,63%±4%,and 39%±7% by SoD,CAT,and vitamin C,respectively（Pon the other hand,CAT had no effect on PE-induced tension,whileSoD enhanced PE-induced tension （36%,Pon induced by *** contrast,SoD or vitamin C hadno effect,but CAT attenuated （44%,Pon induced by ***:We have demonstrated that o2-and H2o2differentially modulate BKrelaxation in an agonist-specific manner.o2-attenuates BK-induced relaxation ofPE contraction,but contributes to the relaxation of ET-1 contraction.o2-seems toinhibit PE contraction,while H2o2contributes to ET-1-induced ***,RoS differentially modulate vascular tone depending on the vasoactive agentthat is used to generate the tone.

关键词： bradykinin endothelin-1 phenylephrine reactive oxygen species superoxide hydrogen peroxide relaxation contraction antioxidants

Blockchain-based DDoS attack mitigation protocol for device-to-device interaction in smart home

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Digital Communications and Networks 2023年第2期9卷 383-392页

作者： Bello Musa yakubu Majid Iqbal Khan Abid Khan Farhana Jabeen Gwanggil Jeon Department of Mathematics and Computer Science Chulalongkorn UniversityBangkok10330Thailand Department of Computer Science COMSATS University Islamabad(CUI)Islamabad45550Pakistan College of Science and Engineering University of DerbyDerbyDE221GBUnited Kingdom Department of Embedded Systems Engineering Incheon National UniversityIncheon22012South Korea

Smart home devices are vulnerable to a variety of *** matter gets more complicated when a number of devices collaborate to launch a colluding attack(e.g.,Distributed-Denial-of-Service(DDoS))in a network(e.g.,Smart home).To handle these attacks,most studies have hitherto proposed authentication protocols that cannot necessarily be implemented in devices,especially during Device-to-Device(D2D)*** into the potential of Ethereum blockchain and smart contracts,this work proposes a lightweight authentication mechanism that enables safe D2D interactions in a smart *** Ethereum blockchain enables the implementation of a decentralized prototype as well as a peer-to-peer distributed ledger *** work also uses a single server queuing system model and the authentication mechanism to curtail DDoS attacks by controlling the number of service requests in the *** simulation was conducted twenty times,each with varying number of devices chosen at random(ranging from 1 to 30).Each requester device sends an arbitrary request with a unique resource requirement at a *** is done to measure the system's consistency across a variety of device *** experimental results show that the proposed protocol not only prevents colluding attacks,but also outperforms the benchmark protocols in terms of computational cost,message processing,and response times.

关键词： DDoS attack Device-to-device Smart homes Blockchain Authentication Ethereum smartcontract

Multivariate Statistical Analysis of Dominating Groundwater Mineralization and Hydrochemical Evolution in Gao,Northern Mali

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Journal of Earth Science 2024年第5期35卷 1692-1703页

作者： Adiaratou Traore Xumei Mao Alhousseyni Traore Yahaya yakubu Aboubacar Modibo Sidibe School of Environmental Studies China University of GeosciencesWuhan 430074China College of Construction Engineering Jilin UniversityChangchun 130012China

Population growth and expanding urbanization have caused persistent shortages and contamination of groundwater resources in Mali,*** increase in groundwater salinity makes it more difficult for residents to obtain drinking water,it is necessary to clarify the causes and control factors of groundwater mineralization in Gao region,northern *** on the analysis of the hydrochemical composition of groundwater in 24 boreholes,Piper and Sch?eller diagrams,principal component analysis(PCA)and hierarchical cluster analysis(HCA)are used to carry out multivariate statistical analysis on the main *** results show that the groundwater samples are weakly alkaline,with pH values ranging from 5.83 to 8.40,and the average values of boreholes are 7.50,*** average electrical conductivity(EC)value is 354.4(μS/cm),and the extreme value is between 124.0 and 1247(μS/cm).Water is usually mineralized and presents nine types of water *** three principal components explain 84.42%of the total variance for 13 *** factor F1(58.85%),the factor F2(16.88%)and the factor F3(8.69%)present for the majority of the total data *** addition,multivariate statistical analysis confirmed the genetic relationship among aquifers and identified three main *** related to groundwater mineralization(F1),clustering related to oxide reduction and iron enrichment(F2),and clustering of groundwater pollution caused by nitrate and magnesium(F3).We found that agriculture,weathering activities and dissolution of geological materials promote the mineralization of *** quality in the Gao region is becoming less and less potable because of increasing salinity.

关键词： hydrochemical composition multivariate statistical analysis mineralization hydro-chemical evolution Gao northern Mali hydrogeology

A review of earthquake occurrences and observations in Nigeria

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Earthquake Science 2010年第3期23卷 289-294页

作者： ofonime Umo Akpan Tahir Abubakar yakubu Centre for Geodesy and Geodynamics

Although Nigeria is not located within the major seismic zones of the world; over the years,several minor earthquakes have been experienced in some parts of the *** first widely reported occurrence of an Earth tremor in Nigeria was in *** events were reported in 1939,1964,1984,1990,1994,1997,2000 and *** intensities of these events ranged from III to VI based on the Modified Mercalli Intensity *** these events,only the 1984,1990,1994 and 2000 events were instrumentally *** had body wave magnitudes ranging from 4.3 to 4.5,local magnitudes between 3.7 and 4.2,and surface wave magnitudes of 3.7 to *** these events occurred,there were no functional seismological observatories in ***,that has now changed with the establishment of a seismographic network managed by the Centre for Geodesy and Geodynamics（CGG）,Toro,***,the network has four operational stations equipped with 24-bit 4-channel recorders and broadband 30-second *** are being made to establish more stations and migrate to real-time collection of seismic data using the general packet radio service（GPRS） technology as well as automatic location of *** sensing,geological and geophysical studies have revealed the presence of a NNE-SSW trending Ifewara-Zungeru fault zone which has been shown to be linked with the Atlantic fracture *** dynamics of the Atlantic fracture zones have been suggested to be responsible for the seismic activities experienced in the areas.

关键词： Nigeria seismic activity seismological observatories Ifewara-Zungeru fault zone

Mathematical modeling of contact tracing and stability analysis to inform its impact on disease outbreaks;an application to CoVID-19

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Infectious Disease Modelling 2024年第2期9卷 329-353页

作者： Mohamed Ladib Aziz ouhinou Abdul-Aziz yakubu University of Sultan Moulay Slimane Faculty of Sciences and TechniquesTeam of Mathematics and InteractionsBéni-MellalMorocco Howard University Dept MathWashingtonDC20059USA

We develop a mathematical model to investigate the effect of contact tracing on containing epidemic outbreaks and slowing down the spread of transmissible *** propose a discrete-time epidemic model structured by disease-age which includes general features of contact *** model is fitted to data reported for the early spread of CoVID-19 in South Korea,Brazil,and *** calibrated values for the contact tracing parameters reflect the order pattern observed in its performance intensity within the three *** the fitted values,we estimate the effective reproduction number R_(e)and investigate its responses to varied control scenarios of contact *** the positivity of solutions,and a stability analysis of the disease-free equilibrium are provided.

关键词： Mathematical modeling Infectious diseases Discrete systems Disease-age structured populations Contact tracing Effective reproduction number CoVID-19

Antifertility effects of 60-day oral gavage of ethanol extract of Spondias mombin leaves in guinea pigs: A biochemical, reproductive and histological study

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Asian pacific Journal of Reproduction 2021年第2期10卷 56-67页

作者： olalekan Bukunmi ogunro Musa Toyin yakubu Phytomedicine ToxicologyReproductive and Developmental Biochemistry Research LaboratoryDepartment of BiochemistryUniversity of IlorinIlorinNigeria Department of Biological Sciences KolaDaisi UniversityIbadanOyo StateNigeria

objective:To investigate the impact of ethanol extract of Spondias(S.)mombin leaves on the biochemical parameters of testicular function,hormonal profile,sperm profile and reproductive outcomes of guinea ***:Sexually matured male[(1000.40±8.12)g]and female[(810.00±7.09)g]guinea pigs were *** testicular function study,a total of 24 male guinea pigs were randomised into 4 groups of 6 guinea pigs *** A(control)was orally administered 1 mL of physiological saline,once daily for 60 days while groups B,C and D were treated like the control group except that they were orally administered 100,250 and 500 mg/kg body weight of ethanol extract of *** *** the fertility study,the same animal groupings and treatments in the testicular function study were *** male guinea pigs were paired with the females(1:1)and afterwards examined for pregnancy ***:The ethanol extract of *** leaves contained saponins,alkaloids,flavonoids,tannins,steroids,phenolics,phlobatannins,cardiac glycosides,cardenolides and dienolides with saponins(4.80 mg/mL)occurring the most whilst cardenolides and dienolides(0.08 mg/mL)were the *** ethanol extract of *** leaves significantly and dose dependently reduced the activities of alkaline phosphatase,glutamate dehydrogenase,3-hydroxy-3-methylglutaryl coenzyme A reductase,malic enzyme,17-β-hydroxysteroid dehydrogenase,lactate dehydrogenase,catalase and superoxide dismutase as well as levels of testosterone,glycogen,total protein and ascorbic acid in the testes when compared with the control group(Poses of ethanol extract of *** leaves also reduced the levels of sorbitol dehydrogenase,3-β-hydroxysteroid dehydrogenase,glucose-6-phosphate dehydrogenase and sialic acid whereas the levels of testicular acid phosphatase,gamma glutamyl transferase and cholesterol increased dose dependently(Pormone,testosterone and estradiol were reduced after the admin

关键词： Anacardiaceae Spondias mombin Guinea pig Testicular dysfunction Anti-spermatogenic Antifertility