Nano-zinc oxides(ZnO)demonstrate remarkable antibacterial properties.To further enhance the corrosion resistance and antibacterial efficiency of magnesium alloy micro-arc oxidation(MAO)coatings,this study investigates...Nano-zinc oxides(ZnO)demonstrate remarkable antibacterial properties.To further enhance the corrosion resistance and antibacterial efficiency of magnesium alloy micro-arc oxidation(MAO)coatings,this study investigates the preparation of ZnO-containing micro-arc oxidation coatings with dual functionality by incorporating nano-ZnO into MAO electrolyte.The influence of varying ZnO concentrations on the microstructure,corrosion resistance,and antibacterial properties of the coating was examined through microstructure analysis,immersion tests,electrochemical experiments,and antibacterial assays.The findings revealed that the addition of nano-ZnO significantly enhanced the corrosion resistance of the MAO-coated alloy.Specifically,when the ZnO concentration in the electrolyte was 5 g/L,the corrosion rate was more than ten times lower compared to the MAO coatings without ZnO.Moreover,the antibacterial efficacy of ZnO+MAO coating,prepared with a ZnO concentration of 5 g/L,surpassed 95%after 24 h of co-culturing with Staphylococcus aureus(S.aureus).The nano-ZnO+MAO-coated alloy exhibited exceptional degradation resistance,corrosion resistance,and antibacterial effectiveness.展开更多
In the process of protecting ferrous materials,aluminum coating usually forms a dense oxide film on the surface of the iron-based alloy.However,the capacity of the sacrificial anode is rather insufficient.In order to ...In the process of protecting ferrous materials,aluminum coating usually forms a dense oxide film on the surface of the iron-based alloy.However,the capacity of the sacrificial anode is rather insufficient.In order to solve this problem,the microstructure and electrochemical corrosion properties of Al-8Si-3Fe-xIn alloy under low chlorine conditions were studied.The results show that indium(In)dissolves to form In^(3+)and In^(+)reverse plating on the surface of the bare substrate to form a passivation film defect.When the In content is high,the segregated In forms an activation point in the form of a cathode phase.In activatesτ_(6)phase to form a micro-couple,which improves the non-uniform corrosion.The In-containing corrosion products at the phase boundary hinder the diffusion of Cl−.With an increase of In content,the self-corrosion potential(Ecorr)of the alloy shifts negatively,and the self-corrosion current density(Jcorr)decreases from 6.477μA/cm^(2)to 1.352μA/cm^(2),and then increases gradually.However,when the In content is 0.1%,the Ecorr of the alloy changes from−0.824 V to−0.932 V,and the Jcorr decreases from 6.477μA/cm^(2)to 4.699μA/cm^(2),suggesting that the use of sacrificial anode will give the best effect.展开更多
This study examined how psychological meaningfulness moderates job complexity and work-family conflict in Nigerian secondary school teachers.This study included 1694 teachers from 17 Nigerian secondary schools(female=6...This study examined how psychological meaningfulness moderates job complexity and work-family conflict in Nigerian secondary school teachers.This study included 1694 teachers from 17 Nigerian secondary schools(female=69.54%,mean age=33.19,SD=6.44 years).The participants completed the Work-family Conflict Scale,Job Complexity Scale,and Psychological Meaningfulness Scale.Study design was cross-sectional.Hayes PROCESS macro analysis results indicate a higher work-family conflict with job complexity among the secondary school teachers.While psychological meaningfulness was not associated with work-family conflict,it moderated the link between job complexity and work-family conflict in secondary school teachers such that a meaningful work endorsement is associated with lower employee’s work-life conflict.Thesefindings point to the importance of job functions to quality of family life.The studyfindings also suggest a need for supporting psychological meaningfulness for healthy work related quality of family life based on balancing work and family role demands.展开更多
This study was conducted to investigate the properties of Pr^(3+)-Dy^(3+)doped Zn_(2)Y-type hexaferrite for potential technological applications.X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FTIR)and ...This study was conducted to investigate the properties of Pr^(3+)-Dy^(3+)doped Zn_(2)Y-type hexaferrite for potential technological applications.X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FTIR)and field-emission scanning electron microscopy(FESEM)were used to analyze structural properties.The crystallite size in the synthesized samples varies between 57.54 and 68.57 nm.The vibrational bands at 400 and 600 cm^(-1),common to all hexaferrites,were confirmed through FTIR.The FESEM analysis reveals an agglomeration of magnetic grains and a decrease in the average grain size from 1.24 to1.06μm.The M-H loops show that,with x values of 0.0,0.1,and 0.2,the saturation magnetization is determined to be 34.76,34.23,and 32.52 emu/g,respectively.The corresponding coercivity values are21.24,30.39,and 33.99 Oe.UV-visible spectroscopy using Tauc theory reveals an increase in the optical band gap from 2.32 to 2.50 eV,indicating a tunable energy band structure by incorporating Pr^(3+)-Dy^(3+)ions.The dielectric constant increases,whereas AC conductivity decreases with increased Pr^(3+)-Dy^(3+)concentration.The obtained results suggest the potential suitability of these materials for various technological applications.展开更多
Ti-15 Zr-xCu(3≤x≤7,wt.%) novel antibacterial and antibiofilm alloys with competitive mechanical properties,biological responses and corrosion resistance were designed and fabricated.Annealing heat treatment on Ti-15...Ti-15 Zr-xCu(3≤x≤7,wt.%) novel antibacterial and antibiofilm alloys with competitive mechanical properties,biological responses and corrosion resistance were designed and fabricated.Annealing heat treatment on Ti-15 Zr-7 Cu(TZC-7 A),after holding for 2 h at slightly above their beta transus temperature(BTT) ensured their tensile strength(UTS),yield strength(YS) and hardness(HRV) were improved by31.2%,20% and 12.3% respectively compared to the control without Cu,Ti-15 Zr(T-15 ZA).Although the3 wt.% Cu alloy displayed the highest elongation(26%),the TZC-7 A alloy also possessed a good ductility.Presence of evenly dispersed Ti2 Cu and Zr2 Cu Cu-rich intermetallic phases formed as interwoven and alternating lamellae within the α+β matrix as a result of Cu addition,as revealed by X-ray diffraction(XRD),scanning electron microscopy(SEM) and transmission electron microscopy(TEM).These greatly contributed to their strengthening and bactericidal properties.Over 98% antibacterial effect against E.coli and S.aureus have been imparted,coupled with excellent biofilm inhibition.Potentiodynamic polarization curves showed that the TZC-7 A alloy possessed higher corrosion resistance than commercially pure titanium,cp-Ti;contact angle test revealed enhanced hydrophilicity;while confocal laser scanning microscopy(CLSM) and cell counting kit(CCK-8) assays also displayed drastically lowered bacterial adhesion rate with comparatively no cytotoxicity.Cell attachment on all alloys was similar but the best spread was obtained on TZC-7 A after 24 h.The developed alloy has good potential as an antibacterial implant material with combination of optimized properties.展开更多
This study investigates the volatility in daily stock returns for Total Nigeria Plc using nine variants of GARCH models:sGARCH,girGARCH,eGARCH,iGARCH,aGARCH,TGARCH,NGARCH,NAGARCH,and AVGARCH along with value at risk e...This study investigates the volatility in daily stock returns for Total Nigeria Plc using nine variants of GARCH models:sGARCH,girGARCH,eGARCH,iGARCH,aGARCH,TGARCH,NGARCH,NAGARCH,and AVGARCH along with value at risk estimation and backtesting.We use daily data for Total Nigeria Plc returns for the period January 2,2001 to May 8,2017,and conclude that eGARCH and sGARCH perform better for normal innovations while NGARCH performs better for student t innovations.This investigation of the volatility,VaR,and backtesting of the daily stock price of Total Nigeria Plc is important as most previous studies covering the Nigerian stock market have not paid much attention to the application of backtesting as a primary approach.We found from the results of the estimations that the persistence of the GARCH models are stable except for few cases for which iGARCH and eGARCH were unstable.Additionally,for student t innovation,the sGARCH and girGARCH models failed to converge;the mean reverting number of days for returns differed from model to model.From the analysis of VaR and its backtesting,this study recommends shareholders and investors continue their business with Total Nigeria Plc because possible losses may be overcome in the future by improvements in stock prices.Furthermore,risk was reflected by significant up and down movement in the stock price at a 99%confidence level,suggesting that high risk brings a high return.展开更多
<span style="font-family:Verdana;">Globally dental diseases are mainly caused by</span><i><span style="font-family:Verdana;"> Streptococcus mutans</span></i><...<span style="font-family:Verdana;">Globally dental diseases are mainly caused by</span><i><span style="font-family:Verdana;"> Streptococcus mutans</span></i><span style="font-family:""><span style="font-family:Verdana;">, it is one of the leading causative agents of dental caries worldwide, because of its resistance to </span><span><span style="font-family:Verdana;">conventional antibacterial agents, alternative therapies are used to control resistance of oral pathogens. This research was done to determine the antibacterial activities of </span><i><span style="font-family:Verdana;">Psidium guajava</span></i><span style="font-family:Verdana;"> (guava) and </span><i><span style="font-family:Verdana;">Velvet tamarin</span></i><span style="font-family:Verdana;"> (Icheku) chewing sticks on </span><i><span style="font-family:Verdana;">Streptococcus mutans</span></i><span style="font-family:Verdana;"> isolated from the oral cavity. The study was conducted in Owerri Imo State Nigeria during November-December</span></span><span style="font-family:Verdana;"> period. Phytochemical analysis of the plant extracts was done using appropriate techniques. The procedure used for antimicrobial susceptibility test was disk diffusion method. Serial dilutions of</span><i><span style="font-family:Verdana;"> Psidium guajava</span></i><span style="font-family:Verdana;"> (guava) and </span><i><span style="font-family:Verdana;">Velvet tamarind</span></i><span style="font-family:Verdana;"> (Icheku) extracts were prepared, Muller-Hinton media was used to put together the extract of serial dilutions of </span><i><span style="font-family:Verdana;">Psidium guajava</span></i><span style="font-family:Verdana;"> (guava) and </span><i><span style="font-family:Verdana;">Velvet tamarin</span></i><span style="font-family:Verdana;"> (Icheku) and </span></span><span style="font-family:Verdana;">a </span><span style="font-family:Verdana;">microbiological procedure w</span><span style="font-family:Verdana;">ere</span><span style="font-family:Verdana;"> used for visually determining the minimum inhibitory concentration as well as minimum bactericidal concentration. Phytochemical evaluation of the plants</span><span style="font-family:Verdana;">’</span><span style="font-family:""><span style="font-family:Verdana;"> extracts revealed that it contains saponins, tannins, alkaloid, steriods, glycosides and phenol. The results obtained from the antibacterial susceptibility testing of the extracts against </span><i><span style="font-family:Verdana;">Streptococcus mutans</span></i><span style="font-family:Verdana;"> showed that the zones of inhibition recorded ranged from 18</span></span><span style="font-family:""> </span><span style="font-family:Verdana;">mm to 27</span><span style="font-family:""> </span><span style="font-family:""><span style="font-family:Verdana;">mm. Ethanol (Soxhlet) extract of I</span><span style="font-family:Verdana;">cheku twig showed no zone of inhibition on the isolated organism. The</span><span style="font-family:Verdana;"> ethanol (soxhlet) extract of the individual </span><i><span style="font-family:Verdana;">Psidium guajava</span></i><span style="font-family:Verdana;"> (guava) and </span><i><span style="font-family:Verdana;">Velvet tamarin</span></i><span style="font-family:Verdana;"> (Icheku) has a better antibacterial effect when compared to their aqueous extracts and combined forms. </span><i><span style="font-family:Verdana;">Psidium guajava</span></i><span style="font-family:Verdana;"> (Guava) and </span><i><span style="font-family:Verdana;">Velvet tamarin</span></i><span style="font-family:Verdana;"> (Icheku) twigs are made up of composite that </span></span><span style="font-family:Verdana;">is</span><span style="font-family:""><span style="font-family:Verdana;"> active against </span><i><span style="font-family:Verdana;">S. mutans</span></i><span style="font-family:Verdana;"> and can be used in oral hygiene. There is </span></span><span style="font-family:Verdana;">a </span><span style="font-family:Verdana;">need for further investigation on the plant extracts as the rural poor make use of it because it is cheap, readily available and the rich also use it once they are in the village mostly in Eastern Nigeria. Similarly chewing sticks has been reported to be practiced by 90 of rural population in Nigeria</span><span style="font-family:Verdana;">.展开更多
Welding as a fabrication process is one of the vital production routes for most manufacturing industries. Several factors are involved in the choice of welding process for specific applications;notable among these are...Welding as a fabrication process is one of the vital production routes for most manufacturing industries. Several factors are involved in the choice of welding process for specific applications;notable among these are compositional range of the material to be welded, the thickness of the base materials and type of current. Most metals oxidize rapidly in their molten state, and therefore, the weld area needs to be protected from atmospheric contamination;this is achieved in gas tungsten arc welding GTAW by a shielding gas (argon, helium, nitrogen). GTAW technique is one of the major processes for joining austenitic stainless steels (ASS) and ferritic stainless steel (FSS) fabrication. However, the microstructural change that occurs during welding and at weld joint is still a major challenge today as it affects both the corrosion resistance and the mechanical properties. Therefore, this present paper reviews past research findings on GTA welding of ASS and FSS. Results of the findings have confirmed that, depending on the amount of heat input, which can be controlled by welding parameters (welding speed, voltage and current), welded joints particularly, heat affected zones (HAZs) of both grades of steels can undergo mechanical failure and can be susceptible to corrosion attack if the joints are produced with a less ideal combination of welding parameters.展开更多
The non-Newtonian blood flow, together with magnetic particles in a stenosed artery, is studied using a magneto-hydrodynamic approach. The wall slip condition is also considered. Approximate solutions are obtained in ...The non-Newtonian blood flow, together with magnetic particles in a stenosed artery, is studied using a magneto-hydrodynamic approach. The wall slip condition is also considered. Approximate solutions are obtained in series forms under the assumption that the Womersley frequency parameter has small values. Using an integral transform method, analytical solutions for any values of the Womersley parameter are obtained.Numerical simulations are performed using MATHCAD to study the influence of stenosis and magnetic field on the flow parameters. When entering the stenosed area, blood velocity increases slightly, but increases considerably and reaches its maximum value in the stenosis throat. It is concluded that the magnitude of axial velocity varies considerably when the applied magnetic field is strong. The magnitude of maximum fluid velocity is high in the case of weak magnetic fields. This is due to the Lorentz's force that opposes motion of an electrically conducting fluid. The effect of externally transverse magnetic field is to decelerate the flow of blood. The shear stress consistently decreases in the presence of a magnetic field with increasing intensity.展开更多
Stream sediment geochemistry remains a versatile tool in exploration especially in regions where knowledge of the primary mineralization is lacking and the exploration activities are still at reconnaissance stage. In ...Stream sediment geochemistry remains a versatile tool in exploration especially in regions where knowledge of the primary mineralization is lacking and the exploration activities are still at reconnaissance stage. In this study, we investigate the concentrations of gold and associated elements in stream sediment samples from the Vaimba-Lidi drainage system in northern Cameroon;a relatively remote area where alluvial gold is worked locally, and exploration activities are at early stage. The main river and its principal first and second order tributaries were sampled, panned for gold grain recovery and the 100 μm size fraction analyzed for Au by fire assay with Ni finish. A suite of other elements were analyzed for by inductively coupled plasma mass spectrometry (ICP-MS). Gold grades estimated by the panning and weighing technique rarely exceed1 g/t while the Au concentrations from chemical analysis range from 3.0 to 354.0 ppm. The spatial distribution of gold and all the other elements are presented as point symbol maps and the data analyzed using multivariate statistics. From the principal component analysis (PCA), the As-Mo-W-Ag as well as the Au-Zn factors point to the presence of primary hydrothermal gold-sulphide mineralization in the area and this can be further investigated. These results highlight the importance of multielement analysis and multivariate statistical interpretation of sediment geochemical data in inferring the nature of the underlying primary mineralization in any region.展开更多
The effects of different aging conditions on the microstructure,strength,corrosion resistance,cytotoxicity and antibacterial ability of Ti-15Zr-xCu(3≤x≤7,wt%)(TZC)alloys were systematically investigated.Microstructu...The effects of different aging conditions on the microstructure,strength,corrosion resistance,cytotoxicity and antibacterial ability of Ti-15Zr-xCu(3≤x≤7,wt%)(TZC)alloys were systematically investigated.Microstructural evolution and behavior were analyzed by X-ray diffraction(XRD)patterns and scanning electron microscopy with energy-dispersive spectroscopy(SEM-EDS),while potentiodynamic polarization technique was employed to characterize the corrosion response of the alloys after solution-treatment and aging(STA).High-temperature aging at 660℃ for 4 h(660-4)gave the best combination of properties by enabling significant precipitation of the Cu-rich Ti_(2)Cu and Zr_(2)Cu compounds,and mild formation of the Zr_(7)Cu_(10) secondary phase.The high kinetics at this condition was beneficial to the complete precipitation and more homogeneous distribution of the intermetallic particles.These led to the inhibition of dislocation movements and allowed for significantly improved mechanical strengths with added ductility,availability of more Cu ions for the desired oligodynamic activity without evoking cytotoxicity,better corrosion resistance and very high antibacterial ability(over 99.5%),thus improving the overall properties of the TZC alloys for biomedical applications.展开更多
This study presents the problem of a steady, two-dimensional, heat and mass transfer of an incompressible, electrically conducting micropolar fluid flow past a stretching surface with velocity and thermal slip conditi...This study presents the problem of a steady, two-dimensional, heat and mass transfer of an incompressible, electrically conducting micropolar fluid flow past a stretching surface with velocity and thermal slip conditions. Also, the influences of temperature dependent viscosity, thermal radiation and non-uniform heat generation/absorption and chemical reaction of a general order are examined on the fluid flow. The governing system of partial differential equations of the fluid flow are transformed into non-linear ordinary differential equations by an appropriate similarity variables and the resulting equations are solved by shooting method coupled with fourth order Runge-Kutta integration scheme. The effects of the controlling parameters on the velocity, temperature, microrotation and concentration profiles as well as on the skin friction, Nusselt number, Sherwood and wall couple stress are investigated through tables and graphs. Comparison of the present results with the existing results in the literature in some limiting cases shows an excellent agreement.展开更多
Numan is an urban center in Adamawa State North-Eastern Nigeria. Its waste characteristics are similar to other places in sub-Saharan Africa. In this paper, the physico-chemical characterization of municipal solid was...Numan is an urban center in Adamawa State North-Eastern Nigeria. Its waste characteristics are similar to other places in sub-Saharan Africa. In this paper, the physico-chemical characterization of municipal solid waste generated in Numan Town was carried out to estimate the electrical power to be generated from it. The solid waste types were observed to comprise of polythene (27%), organic waste (24.1%), plastic (10.2%), textile (13.2%), paper (9.8%), glass (9.3%) and metals (6.4%). The moisture content as discarded and daily average solid waste generation rate are 16.49% and 0.583 kg/sec respectively. The chemical formula with and without water was determined as C923.28H1632.60O258.28N12.89S and C923.28H2099.70O494.16N12.89S respectively. The suitability of the municipal solid waste as a possible source of electrical power was also considered. The energy content of the solid waste on ash free dry-basis was determined as 20861.48 kJ/kg. The estimated power generation per day using incinerating plant at an assumed efficiency of 25% was 3031.5 kW.展开更多
This paper focuses on time series forecasting of monthly occurrence of fatal road accidents in Ondo State of Nigeria. Its aim, however, is to use time series analysis to analyze the data obtained from Federal Road Saf...This paper focuses on time series forecasting of monthly occurrence of fatal road accidents in Ondo State of Nigeria. Its aim, however, is to use time series analysis to analyze the data obtained from Federal Road Safety Corps （FRSC）, Ondo State Command; which was considered in two cases： the total cases reported （TCR） and the number of deaths resulted from accidents （NOD）. Various smoothing models for time series were used to analyze the two cases. Based on the models, predictions were made and the results show a steady increase as a result of long-term effects on road accidents for the two cases. It was found also that simple exponential smoothing model is the appropriate model for both TCR and NOD.展开更多
In this paper, a deterministic mathematical model for Chikungunya virus (Chikv) transmission and control is developed and analyzed to underscore the effect of vaccinating a proportion of the susceptible human, and ver...In this paper, a deterministic mathematical model for Chikungunya virus (Chikv) transmission and control is developed and analyzed to underscore the effect of vaccinating a proportion of the susceptible human, and vertical transmission in mosquito population. The disease free, and endemic equilibrium states were obtained and the conditions for the local and global stability or otherwise were given. Sensitivity analysis of the effective reproductive number,?Rc?(the number of secondary infections resulting from the introduction of a single infected individual into a population where a proportion is fairly protected) shows that the recruitment rate of susceptible mosquito (ΛM) and the proportion of infectious new births from infected mosquito (β)?are the most sensitive parameters. Bifurcation analysis of the model using center manifold theory reveals that the model undergoes backward bifurcation (coexistence of disease free and endemic equilibrium when Rc?< 1 ). Numerical simulation of the model shows that vaccination of susceptible human population with imperfect vaccine will have a positive impact and that vertical transmission in mosquito population has a negligible effect. To the best of our knowledge, our model is the first to incorporate vaccinated human compartment and vertical transmission in (Chikv) model.展开更多
Introduction: A study on the current status of parasitic intestinal helminthes and the efficacy of anthelmintic drug was carried out among primary school pupils at Community Primary School Ogurugu, Uzo-Uwani Local Gov...Introduction: A study on the current status of parasitic intestinal helminthes and the efficacy of anthelmintic drug was carried out among primary school pupils at Community Primary School Ogurugu, Uzo-Uwani Local Government Area, Enugu State. Objectives: The research was conducted in order to determine the prevalence of human intestinal helminthes among primary school pupils, and also to determine the prevalence in relation to age and sex, and to check the efficacy of anthelmintic drug (Levamisole) on the worms, in Ogurugu Uzo-Uwani Local Government Area, Enugu State, Nigeria. Methods: A total of 242 faecal samples were collected randomly from the school children and analyzed using standard parasitological procedures. Results: Data obtained showed an overall prevalence of 143 (59.1%) out of 242 samples and that the efficacy of anthelmintic drug Ergamisole? (Levamisole R12564;Unicure Pvt.ltd India) 50 mg in reducing the worm burden was 99 (82.5%) in 120 samples treated. Age related prevalence and efficacy of anthelmintic varied across the sample groups. There was no significant difference in sex related infections in the sample group (P > 0.5). The efficacy of the drug reduces with the increase in age. Also the efficacy of Levamisole drug in reducing the worm burden were hookworm 59 (89.5%), Ascaris 24 (85.7%), Trichuris 26 (78.6%) while Taenia and Strongyloides showed drug resistance. This indicates that a single dose of the medication is not enough for total elimination of these endo parasites. Conclusion: The study revealed that poor hygienic practices as well as unsanitary conditions were responsible for high prevalence recorded in the area, and advocated health education through primary health care and mass deworming of primary school children as control measures.展开更多
Background: Viruses of the Herpes viridae family infect 90% of the Earth’s population. Humans are the hosts of at least nine unique herpes viruses. Aim: This study is aimed at evaluating the seroprevalence of type sp...Background: Viruses of the Herpes viridae family infect 90% of the Earth’s population. Humans are the hosts of at least nine unique herpes viruses. Aim: This study is aimed at evaluating the seroprevalence of type specific herpes simplex virus infection and the associated risk factors in a cross-section of asymptomatic healthy women of childbearing age in Kogi state, Nigeria. Methodology: A total of 330 females of child bearing age (15 - 49 years) participated in this study. They were recruited from various local government areas of three Senatorial districts of Kogi state. Blood samples were collected from participants and analyzed for HSV-1 and HSV-2 antibodies (IgG) quantitatively with ELISA kit. Results: The overall prevalence of HSV was 76.7%. Data further show that majority (96.4%) of the population studied had HSV-1, while 77% had HSV-2 infections. Results also showed that the young adults indicated prevalence of 95.7% for HSV-1 and 74.7% for HSV-2, while in the middle aged, the prevalence were 98.6% for HSV-1, and 84.9% for HSV-2. 99.2% of the married women were positive for HSV-1, while 86.9% were positive for HSV-2. 94.5% of the unmarried women were positive for HSV-1, while 70.5% were positive for HSV-2. The risk of HVS-1 or VS-2 infections was not associated with age, age of first sexual exposure and number sex partners before marriage. Married women were at greater risk for HSV-1 (p = 0.03) and HSV-2 (p ≤ 0.001) infections compared to the unmarried women. Conclusion: The prevalence of the HSV-1 and HSV-2 infections was high among asymptomatic healthy women of childbearing age in Kogi state, Nigeria. Efforts should be made to increase the awareness of HSV infection among the child bearing populace.展开更多
The problem of accessibility of health institution, with respect to the available facility to serve the entire population leaving in an area, can be solved using GIS. This paper presents an analysis on accessibility o...The problem of accessibility of health institution, with respect to the available facility to serve the entire population leaving in an area, can be solved using GIS. This paper presents an analysis on accessibility of healthcare facilities in Enugu urban area in a GIS environment. This was achieved through acquisition of a base map of Enugu State showing geographic extent of Enugu Urban, determining the geometric positions of health institutions in Enugu urban using handheld GPS, Creation of a spatial database of existing healthcare facilities and demonstrating through various analyses the potentials of GIS in measurement of accessibility to healthcare facilities in Enugu urban Area. The analysis includes network analysis, used to determine the closeness of a facility and shortest route to these healthcare facilities. ARCGIS 9.3 was the main software used. This was supported by Geocal for coordinate conversion and Microsoft office packages. The result of the study showed the spatial distribution of health institutions, closest facilities in case of emergency and route to those health institutions within Enugu urban Area. It was noticed that most of the healthcare facilities were located within Enugu North local government area (LGA). Other settlements and LGAs had fewer healthcare facilities. Areas deprived of healthcare facility were also identified. Routes and closest facilities to those deprived areas were identified in the settlements/area. The analysis showed the efficacy of GIS in determining accessibility of healthcare institutions in Enugu urban area. The study is thus, recommended as a spatial decision support system for decisions regarding spatial accessibility of healthcare facilities in an urban area.展开更多
This paper presents the solution to the combined heat and power economic dispatch problem using a direct solution algorithm for constrained optimization problems. With the potential of Combined Heat and Power (CHP) pr...This paper presents the solution to the combined heat and power economic dispatch problem using a direct solution algorithm for constrained optimization problems. With the potential of Combined Heat and Power (CHP) production to increase the efficiency of power and heat generation simultaneously having been researched and established, the increasing penetration of CHP systems, and determination of economic dispatch of power and heat assumes higher relevance. The Combined Heat and Power Economic Dispatch (CHPED) problem is a demanding optimization problem as both constraints and objective functions can be non-linear and non-convex. This paper presents an explicit formula developed for computing the system-wide incremental costs corresponding with optimal dispatch. The circumvention of the use of iterative search schemes for this crucial step is the innovation inherent in the proposed dispatch procedure. The feasible operating region of the CHP unit three is taken into account in the proposed CHPED problem model, whereas the optimal dispatch of power/heat outputs of CHP unit is determined using the direct Lagrange multiplier solution algorithm. The proposed algorithm is applied to a test system with four units and results are provided.展开更多
基金supported by the National Natural Science Foundation of China(No.52001034)the China Postdoctoral Science Foundation(No.2023M731677)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.KYCX23_3032).
文摘Nano-zinc oxides(ZnO)demonstrate remarkable antibacterial properties.To further enhance the corrosion resistance and antibacterial efficiency of magnesium alloy micro-arc oxidation(MAO)coatings,this study investigates the preparation of ZnO-containing micro-arc oxidation coatings with dual functionality by incorporating nano-ZnO into MAO electrolyte.The influence of varying ZnO concentrations on the microstructure,corrosion resistance,and antibacterial properties of the coating was examined through microstructure analysis,immersion tests,electrochemical experiments,and antibacterial assays.The findings revealed that the addition of nano-ZnO significantly enhanced the corrosion resistance of the MAO-coated alloy.Specifically,when the ZnO concentration in the electrolyte was 5 g/L,the corrosion rate was more than ten times lower compared to the MAO coatings without ZnO.Moreover,the antibacterial efficacy of ZnO+MAO coating,prepared with a ZnO concentration of 5 g/L,surpassed 95%after 24 h of co-culturing with Staphylococcus aureus(S.aureus).The nano-ZnO+MAO-coated alloy exhibited exceptional degradation resistance,corrosion resistance,and antibacterial effectiveness.
基金Projects(52171003,52271005)supported by the National Science and Technology Major Project of ChinaProject(KYCX23_3032)supported by the Postgraduate Research&Practice Innovation Program of Jiangsu Province,China。
文摘In the process of protecting ferrous materials,aluminum coating usually forms a dense oxide film on the surface of the iron-based alloy.However,the capacity of the sacrificial anode is rather insufficient.In order to solve this problem,the microstructure and electrochemical corrosion properties of Al-8Si-3Fe-xIn alloy under low chlorine conditions were studied.The results show that indium(In)dissolves to form In^(3+)and In^(+)reverse plating on the surface of the bare substrate to form a passivation film defect.When the In content is high,the segregated In forms an activation point in the form of a cathode phase.In activatesτ_(6)phase to form a micro-couple,which improves the non-uniform corrosion.The In-containing corrosion products at the phase boundary hinder the diffusion of Cl−.With an increase of In content,the self-corrosion potential(Ecorr)of the alloy shifts negatively,and the self-corrosion current density(Jcorr)decreases from 6.477μA/cm^(2)to 1.352μA/cm^(2),and then increases gradually.However,when the In content is 0.1%,the Ecorr of the alloy changes from−0.824 V to−0.932 V,and the Jcorr decreases from 6.477μA/cm^(2)to 4.699μA/cm^(2),suggesting that the use of sacrificial anode will give the best effect.
文摘This study examined how psychological meaningfulness moderates job complexity and work-family conflict in Nigerian secondary school teachers.This study included 1694 teachers from 17 Nigerian secondary schools(female=69.54%,mean age=33.19,SD=6.44 years).The participants completed the Work-family Conflict Scale,Job Complexity Scale,and Psychological Meaningfulness Scale.Study design was cross-sectional.Hayes PROCESS macro analysis results indicate a higher work-family conflict with job complexity among the secondary school teachers.While psychological meaningfulness was not associated with work-family conflict,it moderated the link between job complexity and work-family conflict in secondary school teachers such that a meaningful work endorsement is associated with lower employee’s work-life conflict.Thesefindings point to the importance of job functions to quality of family life.The studyfindings also suggest a need for supporting psychological meaningfulness for healthy work related quality of family life based on balancing work and family role demands.
基金the Deanship of Scientific Research at King Khalid University for funding this work through large group Research Project under grant number RGP2/226/44。
文摘This study was conducted to investigate the properties of Pr^(3+)-Dy^(3+)doped Zn_(2)Y-type hexaferrite for potential technological applications.X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FTIR)and field-emission scanning electron microscopy(FESEM)were used to analyze structural properties.The crystallite size in the synthesized samples varies between 57.54 and 68.57 nm.The vibrational bands at 400 and 600 cm^(-1),common to all hexaferrites,were confirmed through FTIR.The FESEM analysis reveals an agglomeration of magnetic grains and a decrease in the average grain size from 1.24 to1.06μm.The M-H loops show that,with x values of 0.0,0.1,and 0.2,the saturation magnetization is determined to be 34.76,34.23,and 32.52 emu/g,respectively.The corresponding coercivity values are21.24,30.39,and 33.99 Oe.UV-visible spectroscopy using Tauc theory reveals an increase in the optical band gap from 2.32 to 2.50 eV,indicating a tunable energy band structure by incorporating Pr^(3+)-Dy^(3+)ions.The dielectric constant increases,whereas AC conductivity decreases with increased Pr^(3+)-Dy^(3+)concentration.The obtained results suggest the potential suitability of these materials for various technological applications.
基金supported financially by the National Key Research and Development Program of China (Nos. 2018YFC1106601 and 2016YFC1100600)National Natural Science Foundation (No. 51631009)+2 种基金Youth Innovation Promotion Association, CAS (No. 2014168)Promoting Liaoning Province Talents Program-Top Young Talents (XLYC1807069)the support of CAS-TWAS President Fellowship。
文摘Ti-15 Zr-xCu(3≤x≤7,wt.%) novel antibacterial and antibiofilm alloys with competitive mechanical properties,biological responses and corrosion resistance were designed and fabricated.Annealing heat treatment on Ti-15 Zr-7 Cu(TZC-7 A),after holding for 2 h at slightly above their beta transus temperature(BTT) ensured their tensile strength(UTS),yield strength(YS) and hardness(HRV) were improved by31.2%,20% and 12.3% respectively compared to the control without Cu,Ti-15 Zr(T-15 ZA).Although the3 wt.% Cu alloy displayed the highest elongation(26%),the TZC-7 A alloy also possessed a good ductility.Presence of evenly dispersed Ti2 Cu and Zr2 Cu Cu-rich intermetallic phases formed as interwoven and alternating lamellae within the α+β matrix as a result of Cu addition,as revealed by X-ray diffraction(XRD),scanning electron microscopy(SEM) and transmission electron microscopy(TEM).These greatly contributed to their strengthening and bactericidal properties.Over 98% antibacterial effect against E.coli and S.aureus have been imparted,coupled with excellent biofilm inhibition.Potentiodynamic polarization curves showed that the TZC-7 A alloy possessed higher corrosion resistance than commercially pure titanium,cp-Ti;contact angle test revealed enhanced hydrophilicity;while confocal laser scanning microscopy(CLSM) and cell counting kit(CCK-8) assays also displayed drastically lowered bacterial adhesion rate with comparatively no cytotoxicity.Cell attachment on all alloys was similar but the best spread was obtained on TZC-7 A after 24 h.The developed alloy has good potential as an antibacterial implant material with combination of optimized properties.
文摘This study investigates the volatility in daily stock returns for Total Nigeria Plc using nine variants of GARCH models:sGARCH,girGARCH,eGARCH,iGARCH,aGARCH,TGARCH,NGARCH,NAGARCH,and AVGARCH along with value at risk estimation and backtesting.We use daily data for Total Nigeria Plc returns for the period January 2,2001 to May 8,2017,and conclude that eGARCH and sGARCH perform better for normal innovations while NGARCH performs better for student t innovations.This investigation of the volatility,VaR,and backtesting of the daily stock price of Total Nigeria Plc is important as most previous studies covering the Nigerian stock market have not paid much attention to the application of backtesting as a primary approach.We found from the results of the estimations that the persistence of the GARCH models are stable except for few cases for which iGARCH and eGARCH were unstable.Additionally,for student t innovation,the sGARCH and girGARCH models failed to converge;the mean reverting number of days for returns differed from model to model.From the analysis of VaR and its backtesting,this study recommends shareholders and investors continue their business with Total Nigeria Plc because possible losses may be overcome in the future by improvements in stock prices.Furthermore,risk was reflected by significant up and down movement in the stock price at a 99%confidence level,suggesting that high risk brings a high return.
文摘<span style="font-family:Verdana;">Globally dental diseases are mainly caused by</span><i><span style="font-family:Verdana;"> Streptococcus mutans</span></i><span style="font-family:""><span style="font-family:Verdana;">, it is one of the leading causative agents of dental caries worldwide, because of its resistance to </span><span><span style="font-family:Verdana;">conventional antibacterial agents, alternative therapies are used to control resistance of oral pathogens. This research was done to determine the antibacterial activities of </span><i><span style="font-family:Verdana;">Psidium guajava</span></i><span style="font-family:Verdana;"> (guava) and </span><i><span style="font-family:Verdana;">Velvet tamarin</span></i><span style="font-family:Verdana;"> (Icheku) chewing sticks on </span><i><span style="font-family:Verdana;">Streptococcus mutans</span></i><span style="font-family:Verdana;"> isolated from the oral cavity. The study was conducted in Owerri Imo State Nigeria during November-December</span></span><span style="font-family:Verdana;"> period. Phytochemical analysis of the plant extracts was done using appropriate techniques. The procedure used for antimicrobial susceptibility test was disk diffusion method. Serial dilutions of</span><i><span style="font-family:Verdana;"> Psidium guajava</span></i><span style="font-family:Verdana;"> (guava) and </span><i><span style="font-family:Verdana;">Velvet tamarind</span></i><span style="font-family:Verdana;"> (Icheku) extracts were prepared, Muller-Hinton media was used to put together the extract of serial dilutions of </span><i><span style="font-family:Verdana;">Psidium guajava</span></i><span style="font-family:Verdana;"> (guava) and </span><i><span style="font-family:Verdana;">Velvet tamarin</span></i><span style="font-family:Verdana;"> (Icheku) and </span></span><span style="font-family:Verdana;">a </span><span style="font-family:Verdana;">microbiological procedure w</span><span style="font-family:Verdana;">ere</span><span style="font-family:Verdana;"> used for visually determining the minimum inhibitory concentration as well as minimum bactericidal concentration. Phytochemical evaluation of the plants</span><span style="font-family:Verdana;">’</span><span style="font-family:""><span style="font-family:Verdana;"> extracts revealed that it contains saponins, tannins, alkaloid, steriods, glycosides and phenol. The results obtained from the antibacterial susceptibility testing of the extracts against </span><i><span style="font-family:Verdana;">Streptococcus mutans</span></i><span style="font-family:Verdana;"> showed that the zones of inhibition recorded ranged from 18</span></span><span style="font-family:""> </span><span style="font-family:Verdana;">mm to 27</span><span style="font-family:""> </span><span style="font-family:""><span style="font-family:Verdana;">mm. Ethanol (Soxhlet) extract of I</span><span style="font-family:Verdana;">cheku twig showed no zone of inhibition on the isolated organism. The</span><span style="font-family:Verdana;"> ethanol (soxhlet) extract of the individual </span><i><span style="font-family:Verdana;">Psidium guajava</span></i><span style="font-family:Verdana;"> (guava) and </span><i><span style="font-family:Verdana;">Velvet tamarin</span></i><span style="font-family:Verdana;"> (Icheku) has a better antibacterial effect when compared to their aqueous extracts and combined forms. </span><i><span style="font-family:Verdana;">Psidium guajava</span></i><span style="font-family:Verdana;"> (Guava) and </span><i><span style="font-family:Verdana;">Velvet tamarin</span></i><span style="font-family:Verdana;"> (Icheku) twigs are made up of composite that </span></span><span style="font-family:Verdana;">is</span><span style="font-family:""><span style="font-family:Verdana;"> active against </span><i><span style="font-family:Verdana;">S. mutans</span></i><span style="font-family:Verdana;"> and can be used in oral hygiene. There is </span></span><span style="font-family:Verdana;">a </span><span style="font-family:Verdana;">need for further investigation on the plant extracts as the rural poor make use of it because it is cheap, readily available and the rich also use it once they are in the village mostly in Eastern Nigeria. Similarly chewing sticks has been reported to be practiced by 90 of rural population in Nigeria</span><span style="font-family:Verdana;">.
文摘Welding as a fabrication process is one of the vital production routes for most manufacturing industries. Several factors are involved in the choice of welding process for specific applications;notable among these are compositional range of the material to be welded, the thickness of the base materials and type of current. Most metals oxidize rapidly in their molten state, and therefore, the weld area needs to be protected from atmospheric contamination;this is achieved in gas tungsten arc welding GTAW by a shielding gas (argon, helium, nitrogen). GTAW technique is one of the major processes for joining austenitic stainless steels (ASS) and ferritic stainless steel (FSS) fabrication. However, the microstructural change that occurs during welding and at weld joint is still a major challenge today as it affects both the corrosion resistance and the mechanical properties. Therefore, this present paper reviews past research findings on GTA welding of ASS and FSS. Results of the findings have confirmed that, depending on the amount of heat input, which can be controlled by welding parameters (welding speed, voltage and current), welded joints particularly, heat affected zones (HAZs) of both grades of steels can undergo mechanical failure and can be susceptible to corrosion attack if the joints are produced with a less ideal combination of welding parameters.
基金Project supported by the Tertiary Education Trust Fund of Nigeria(TETFund)(No.FPTB-2016)
文摘The non-Newtonian blood flow, together with magnetic particles in a stenosed artery, is studied using a magneto-hydrodynamic approach. The wall slip condition is also considered. Approximate solutions are obtained in series forms under the assumption that the Womersley frequency parameter has small values. Using an integral transform method, analytical solutions for any values of the Womersley parameter are obtained.Numerical simulations are performed using MATHCAD to study the influence of stenosis and magnetic field on the flow parameters. When entering the stenosed area, blood velocity increases slightly, but increases considerably and reaches its maximum value in the stenosis throat. It is concluded that the magnitude of axial velocity varies considerably when the applied magnetic field is strong. The magnitude of maximum fluid velocity is high in the case of weak magnetic fields. This is due to the Lorentz's force that opposes motion of an electrically conducting fluid. The effect of externally transverse magnetic field is to decelerate the flow of blood. The shear stress consistently decreases in the presence of a magnetic field with increasing intensity.
文摘Stream sediment geochemistry remains a versatile tool in exploration especially in regions where knowledge of the primary mineralization is lacking and the exploration activities are still at reconnaissance stage. In this study, we investigate the concentrations of gold and associated elements in stream sediment samples from the Vaimba-Lidi drainage system in northern Cameroon;a relatively remote area where alluvial gold is worked locally, and exploration activities are at early stage. The main river and its principal first and second order tributaries were sampled, panned for gold grain recovery and the 100 μm size fraction analyzed for Au by fire assay with Ni finish. A suite of other elements were analyzed for by inductively coupled plasma mass spectrometry (ICP-MS). Gold grades estimated by the panning and weighing technique rarely exceed1 g/t while the Au concentrations from chemical analysis range from 3.0 to 354.0 ppm. The spatial distribution of gold and all the other elements are presented as point symbol maps and the data analyzed using multivariate statistics. From the principal component analysis (PCA), the As-Mo-W-Ag as well as the Au-Zn factors point to the presence of primary hydrothermal gold-sulphide mineralization in the area and this can be further investigated. These results highlight the importance of multielement analysis and multivariate statistical interpretation of sediment geochemical data in inferring the nature of the underlying primary mineralization in any region.
基金financially supported by the National Natural Science Foundation of China(Nos.51631009 and 31870954).S.K.Kolawole graciously appreciates CAS-TWAS President Fellowship for the scholarship aid。
文摘The effects of different aging conditions on the microstructure,strength,corrosion resistance,cytotoxicity and antibacterial ability of Ti-15Zr-xCu(3≤x≤7,wt%)(TZC)alloys were systematically investigated.Microstructural evolution and behavior were analyzed by X-ray diffraction(XRD)patterns and scanning electron microscopy with energy-dispersive spectroscopy(SEM-EDS),while potentiodynamic polarization technique was employed to characterize the corrosion response of the alloys after solution-treatment and aging(STA).High-temperature aging at 660℃ for 4 h(660-4)gave the best combination of properties by enabling significant precipitation of the Cu-rich Ti_(2)Cu and Zr_(2)Cu compounds,and mild formation of the Zr_(7)Cu_(10) secondary phase.The high kinetics at this condition was beneficial to the complete precipitation and more homogeneous distribution of the intermetallic particles.These led to the inhibition of dislocation movements and allowed for significantly improved mechanical strengths with added ductility,availability of more Cu ions for the desired oligodynamic activity without evoking cytotoxicity,better corrosion resistance and very high antibacterial ability(over 99.5%),thus improving the overall properties of the TZC alloys for biomedical applications.
文摘This study presents the problem of a steady, two-dimensional, heat and mass transfer of an incompressible, electrically conducting micropolar fluid flow past a stretching surface with velocity and thermal slip conditions. Also, the influences of temperature dependent viscosity, thermal radiation and non-uniform heat generation/absorption and chemical reaction of a general order are examined on the fluid flow. The governing system of partial differential equations of the fluid flow are transformed into non-linear ordinary differential equations by an appropriate similarity variables and the resulting equations are solved by shooting method coupled with fourth order Runge-Kutta integration scheme. The effects of the controlling parameters on the velocity, temperature, microrotation and concentration profiles as well as on the skin friction, Nusselt number, Sherwood and wall couple stress are investigated through tables and graphs. Comparison of the present results with the existing results in the literature in some limiting cases shows an excellent agreement.
文摘Numan is an urban center in Adamawa State North-Eastern Nigeria. Its waste characteristics are similar to other places in sub-Saharan Africa. In this paper, the physico-chemical characterization of municipal solid waste generated in Numan Town was carried out to estimate the electrical power to be generated from it. The solid waste types were observed to comprise of polythene (27%), organic waste (24.1%), plastic (10.2%), textile (13.2%), paper (9.8%), glass (9.3%) and metals (6.4%). The moisture content as discarded and daily average solid waste generation rate are 16.49% and 0.583 kg/sec respectively. The chemical formula with and without water was determined as C923.28H1632.60O258.28N12.89S and C923.28H2099.70O494.16N12.89S respectively. The suitability of the municipal solid waste as a possible source of electrical power was also considered. The energy content of the solid waste on ash free dry-basis was determined as 20861.48 kJ/kg. The estimated power generation per day using incinerating plant at an assumed efficiency of 25% was 3031.5 kW.
文摘This paper focuses on time series forecasting of monthly occurrence of fatal road accidents in Ondo State of Nigeria. Its aim, however, is to use time series analysis to analyze the data obtained from Federal Road Safety Corps （FRSC）, Ondo State Command; which was considered in two cases： the total cases reported （TCR） and the number of deaths resulted from accidents （NOD）. Various smoothing models for time series were used to analyze the two cases. Based on the models, predictions were made and the results show a steady increase as a result of long-term effects on road accidents for the two cases. It was found also that simple exponential smoothing model is the appropriate model for both TCR and NOD.
文摘In this paper, a deterministic mathematical model for Chikungunya virus (Chikv) transmission and control is developed and analyzed to underscore the effect of vaccinating a proportion of the susceptible human, and vertical transmission in mosquito population. The disease free, and endemic equilibrium states were obtained and the conditions for the local and global stability or otherwise were given. Sensitivity analysis of the effective reproductive number,?Rc?(the number of secondary infections resulting from the introduction of a single infected individual into a population where a proportion is fairly protected) shows that the recruitment rate of susceptible mosquito (ΛM) and the proportion of infectious new births from infected mosquito (β)?are the most sensitive parameters. Bifurcation analysis of the model using center manifold theory reveals that the model undergoes backward bifurcation (coexistence of disease free and endemic equilibrium when Rc?< 1 ). Numerical simulation of the model shows that vaccination of susceptible human population with imperfect vaccine will have a positive impact and that vertical transmission in mosquito population has a negligible effect. To the best of our knowledge, our model is the first to incorporate vaccinated human compartment and vertical transmission in (Chikv) model.
文摘Introduction: A study on the current status of parasitic intestinal helminthes and the efficacy of anthelmintic drug was carried out among primary school pupils at Community Primary School Ogurugu, Uzo-Uwani Local Government Area, Enugu State. Objectives: The research was conducted in order to determine the prevalence of human intestinal helminthes among primary school pupils, and also to determine the prevalence in relation to age and sex, and to check the efficacy of anthelmintic drug (Levamisole) on the worms, in Ogurugu Uzo-Uwani Local Government Area, Enugu State, Nigeria. Methods: A total of 242 faecal samples were collected randomly from the school children and analyzed using standard parasitological procedures. Results: Data obtained showed an overall prevalence of 143 (59.1%) out of 242 samples and that the efficacy of anthelmintic drug Ergamisole? (Levamisole R12564;Unicure Pvt.ltd India) 50 mg in reducing the worm burden was 99 (82.5%) in 120 samples treated. Age related prevalence and efficacy of anthelmintic varied across the sample groups. There was no significant difference in sex related infections in the sample group (P > 0.5). The efficacy of the drug reduces with the increase in age. Also the efficacy of Levamisole drug in reducing the worm burden were hookworm 59 (89.5%), Ascaris 24 (85.7%), Trichuris 26 (78.6%) while Taenia and Strongyloides showed drug resistance. This indicates that a single dose of the medication is not enough for total elimination of these endo parasites. Conclusion: The study revealed that poor hygienic practices as well as unsanitary conditions were responsible for high prevalence recorded in the area, and advocated health education through primary health care and mass deworming of primary school children as control measures.
文摘Background: Viruses of the Herpes viridae family infect 90% of the Earth’s population. Humans are the hosts of at least nine unique herpes viruses. Aim: This study is aimed at evaluating the seroprevalence of type specific herpes simplex virus infection and the associated risk factors in a cross-section of asymptomatic healthy women of childbearing age in Kogi state, Nigeria. Methodology: A total of 330 females of child bearing age (15 - 49 years) participated in this study. They were recruited from various local government areas of three Senatorial districts of Kogi state. Blood samples were collected from participants and analyzed for HSV-1 and HSV-2 antibodies (IgG) quantitatively with ELISA kit. Results: The overall prevalence of HSV was 76.7%. Data further show that majority (96.4%) of the population studied had HSV-1, while 77% had HSV-2 infections. Results also showed that the young adults indicated prevalence of 95.7% for HSV-1 and 74.7% for HSV-2, while in the middle aged, the prevalence were 98.6% for HSV-1, and 84.9% for HSV-2. 99.2% of the married women were positive for HSV-1, while 86.9% were positive for HSV-2. 94.5% of the unmarried women were positive for HSV-1, while 70.5% were positive for HSV-2. The risk of HVS-1 or VS-2 infections was not associated with age, age of first sexual exposure and number sex partners before marriage. Married women were at greater risk for HSV-1 (p = 0.03) and HSV-2 (p ≤ 0.001) infections compared to the unmarried women. Conclusion: The prevalence of the HSV-1 and HSV-2 infections was high among asymptomatic healthy women of childbearing age in Kogi state, Nigeria. Efforts should be made to increase the awareness of HSV infection among the child bearing populace.
文摘The problem of accessibility of health institution, with respect to the available facility to serve the entire population leaving in an area, can be solved using GIS. This paper presents an analysis on accessibility of healthcare facilities in Enugu urban area in a GIS environment. This was achieved through acquisition of a base map of Enugu State showing geographic extent of Enugu Urban, determining the geometric positions of health institutions in Enugu urban using handheld GPS, Creation of a spatial database of existing healthcare facilities and demonstrating through various analyses the potentials of GIS in measurement of accessibility to healthcare facilities in Enugu urban Area. The analysis includes network analysis, used to determine the closeness of a facility and shortest route to these healthcare facilities. ARCGIS 9.3 was the main software used. This was supported by Geocal for coordinate conversion and Microsoft office packages. The result of the study showed the spatial distribution of health institutions, closest facilities in case of emergency and route to those health institutions within Enugu urban Area. It was noticed that most of the healthcare facilities were located within Enugu North local government area (LGA). Other settlements and LGAs had fewer healthcare facilities. Areas deprived of healthcare facility were also identified. Routes and closest facilities to those deprived areas were identified in the settlements/area. The analysis showed the efficacy of GIS in determining accessibility of healthcare institutions in Enugu urban area. The study is thus, recommended as a spatial decision support system for decisions regarding spatial accessibility of healthcare facilities in an urban area.
文摘This paper presents the solution to the combined heat and power economic dispatch problem using a direct solution algorithm for constrained optimization problems. With the potential of Combined Heat and Power (CHP) production to increase the efficiency of power and heat generation simultaneously having been researched and established, the increasing penetration of CHP systems, and determination of economic dispatch of power and heat assumes higher relevance. The Combined Heat and Power Economic Dispatch (CHPED) problem is a demanding optimization problem as both constraints and objective functions can be non-linear and non-convex. This paper presents an explicit formula developed for computing the system-wide incremental costs corresponding with optimal dispatch. The circumvention of the use of iterative search schemes for this crucial step is the innovation inherent in the proposed dispatch procedure. The feasible operating region of the CHP unit three is taken into account in the proposed CHPED problem model, whereas the optimal dispatch of power/heat outputs of CHP unit is determined using the direct Lagrange multiplier solution algorithm. The proposed algorithm is applied to a test system with four units and results are provided.
