Evaluation of combined heat treatment techniques of testing hardness and tensile strength of mild carbon steel commonly used in Nigeria

This study investigated effect of combined heat treatment on the hardness and tensile strength of 0.25 - 0.35 grade of medium carbon steel. Heat treatment at 900 °C for four hours was done and six specimens of each were then quenched in water. Results showed that the hardness and tensile strength ranged from 113.7 to 184.4 HB and from 383.84 to 621.2 N/mm2, respectively, for hardening temperature from 700 to 950 °C; and were from 180.2 to 125.5 HB and 594.7 to 4143 N/mm2, respectively, when the steel was quenched from 900 °C for tempering temperatures from 250 to 600 °C. The result of tempering (from 250 to 600 °C) when previously quenched (from 850 °C) steel showed decreasing values of hardness (from 400 to 248 HB) and of tensile strength (from 1320 to 819 N/mm2). The microstructure of the normalized sample was observed to be finer and more homogenized than the one observed in the as-rolled condition of the sample. This invariably led to the higher hardness and tensile strength values recorded.Keywords: Hardness, Tensile strength, quenching, microstructure, ferrit

Techno-Economic and Life Cycle Analysis of Energy Generation Using Concentrated Solar Power (CSP) Technology in Sokoto State. Nigeria

: In this work a predictive performance simulation of Solar Tower, Linear Fresnel and Parabolic Trough Concentrating Solar Power (CSP) plants was undertaken for Sokoto State in Northwestern Nigeria. The State was selected based on its high Direct Normal Irradiation (DNI) values and long hours of sunshine per day relative to other places in Nigeria. The simulation was done using System Advisor Model (SAM) Software. In the study, 50 MW, 75 MW and 100 MW for each of the three CSP technologies were considered and their Techno-economic and Life Cycle analyses were carried out. The results showed that Solar Tower plant is more favored to be adopted for use in the studied site because it has the highest annual electrical energy generation, higher capacity factor and lowest Levelised cost of Electricity. The Net Present Values of the CSP plants at the site are (with the exception of the 50 MW Linear Fresnel CSP using hybrid cooling) positive implying that the project is economically viable. The study also showed that at solar multiple of 2, the Levelised costs of Electricity for both Solar Towers and Parabolic Troughs were the lowest, irrespective of the cooling system (wet or dry cooling). Solar multiple has no effect on the water usage irrespective of the CSP plant. Dry cooling system reduces the water usage by 86% and 95% for Solar Tower and Parabolic Trough plants, respectively. Dry cooling system reduces the annual electrical energy generation in the range of 7.3 to 7.5 percent for Solar Tower plant and 8 to 9 percent for Parabolic Trough plant. The largest environmental impact was human toxicity at 25,400 g 1,4-DB eq. and the least is marine ecotoxicity at 1.33 × 10-4 g 1,4-DB eq.Keywords: Annual Generation; Debt Fraction; Human toxicity; Freshwater Eutrophicatio

Leukocyte changes in pregnant Yankasa ewes experimentally infected with Trypanosoma evansi

Pregnancy and trypanosomosis are associated with leukocyte changes. The leukocyte response of pregnant Yankasa ewes during experimental Trypanosoma evansi infection was determined using twenty pregnant ewes. They ewes were divided into 3 groups with 6 ewes in group A, while groups B and C were made up of 7 ewes each. The ewes in group A served as control, whereas those in group B and C were infected with approximately 1.0 x106 parasite/mL of T. evansi (Sokoto isolate) per ewe through the jugular vein on days 59 and 110 of pregnancy, respectively. Blood from each ewe was collected weekly and used to monitor leukocyte changes from the time of parasitaemia till the end of the study. There was significant (p<0.05) leukopenia in group B at week 1 pi, followed by significant (p<0.05) leukocytosis at week 4 pi and leukopenia at week 7 pi compared with the control. The leukopenic animals were characterized by neutropenia and monocytosis, while the leukocytosis was due to eosinophilia, neutrophilia and monocytosis that were observed with peak parasitaemia. Ewes in group C had significant (p<0.05) leukopenia at week 3 compared to the control and this preceded peak parasitaemia but characterized by lymphocytopenia and eosinopenia. In conclusion, the study shows that T. evansi (Sokoto isolate) causes leukocyte changes in pregnant ewes infected at second trimester different from ewes infected at third trimester, suggesting that trimester of pregnancy affects leukocyte response in T. evansi infection.Keywords: Ewe, Leucocytosis, Leucopenia, Monocytosis, Pregnancy, Trypanosoma evans

Sex and age related variations in somatotype of ethnic Hausa adolescents' from Zaria, north-west Nigeria

No Abstract

Detection of Multidrug-Resistant Acinetobacter baumannii among Gram-Negative Bacteria Isolated from Clinical Samples

Acinetobacter baumannii is an aerobic, Gram -negative cocco-bacilli, non-fermentative, non-motile, and non-fastidious organism belonging to the genus Acinetobacter. The A. baumannii has emerged as a worldwide nosocomial pathogen causing about 80%25 of nosocomial infections comprising ventilator-acquired pneumonia, bacteremia, meningitis, urinary tract infections, skin and soft tissues infections associated with high mortality rate of approximately 63.3%25. Although literature shows sufficient information about the drug resistant A. baumannii, there has been inadequate reports on the antibiotic resistance level of this bacterium in the study area. The aim of this research was to detect Multidrug-resistant A. baumannii isolates among Gram-negative bacteria isolated from Federal Teaching Hospital, Gombe, Nigeria. A total of 1008 clinical samples were collected and cultured on MacConkey agar and Blood agar plates at 37o C for 18-24 hours. Following the incubation period, discrete colonies obtained were subjected to Gram staining. The Gram-negative isolates were identified based on conventional biochemical tests with further use of VITEK 2 COMPACT (BioMérieux, France) for confirmation of A. baumannii amongst the Gram-negative organisms. The results obtained showed that 263 Gram-negative organisms were isolated. A. baumannii accounted for 8.5%25 prevalence. Most of the A. baumannii isolated were from the male patients (75%25) within the age range of 33-48 years. Antibiotic susceptibility test using Kirby Bauer method in accordance with CLSI guidelines was done on 20 A. baumannii isolates. The isolates were more sensitive to levofloxacin (60%25), followed by Gentamicin (55%25), then Ciprofloxacin and Tetracycline (50%25) respectively. High level of resistance to Ceftriaxone (80%25), Cefepime (75%25), Ceftazidime (65%25), Piperacillin-Tazobactam (55%25), Ampicillin%252FSulbactam (60%25), Tigecycline (60%25), Meropenem (55%25) and Amikacin (60%25). This study revealed that 15 (75%25) of the A. baumannii were found to be multidrug-resistant. Therefore, antibiotic stewardship is necessary to combat further dissemination of this organism

Mathematical Modelling of Dynamics of HIV Transmission Depicting the Importance of Counseling and Treatment

Human immunodeficiency virus is an incurable disease which attacks and destroys the human immunesystem thereby making the body susceptible to all kinds of illnesses. If left unattended to, it can lead to the damaging ofbody organs such as the brain, kidney and the heart which can result to death. Unfortunately this disease has no knowncure till date but through counseling and administering of antiretroviral drugs, the likelihood of dying from it becomesminimal. This study presents the deterministic HIV transmission model. The model has a unique endemic equilibrium point which is locally asymptotically stable if R0  > 1 , DFE of the model was obtained and is shown to be Localasymptotically stable when the associated basic reproduction number was R > 1. We established the numerical simulation of the model which shows that the effective use of condom, counseling or the use of anti-retrovirus drug can lead to effective reduction on HIV transmission. Finally, we discussed that the ART treatment rate will reduce the basic reproduction number R0 hence, leading to the extinction of HIV/AIDS

Growth and yield components of some groundnut (Arachis hypogaea L.) cultivars infected with blackeye cowpea mosaic virus

Blackeye cowpea mosaic virus (BlCMV) is a major virus, infecting legumes with attendant huge losses. Cultivation of resistant varieties is the most effective and sustainable control strategy. Therefore, some groundnut (Arachis hypogaea) cultivars were evaluated against BlCMV in Minna, Southern Guinea savanna zone of Nigeria. The experiment was conducted at the Teaching and Research Farm, Federal University of Technology, Minna. It was arranged as infected and uninfected using Randomised Complete Block Design (RCBD) with three replications. Groundnut seeds were sowed in the second week of August, 2015. Seedlings were inoculated by sap transmission at 10 days after sowing. Disease incidence, severity, growth and yield attributes were recorded. Data were subjected to analysis of variance (ANOVA) and means separated at p≤0.05 probability level. Disease incidence varied significantly p<0.05 from 28.3 to 60.3 % at one week after inoculation (WAI) and 44.7 to 100 % at 2 WAI. ICGV 91317 which expressed mild infection (symptom score = 2) at 9 WAI also exhibited the lowest leaf diameter reduction (3.6 %) at that growth stage. FDRF7-82 which had the lowest reduction in number of leaves per plant at 3 and 6WAI (10.7 and 9.6 %, respectively) also exhibited the lowest reduction in fresh haulm weight per plant (42.2 %). None of the cultivars exhibited consistent reactions, FDRF7-82 and ICGV 91317 had an appreciable combination of growth and yield attributes under BlCMV infection. However, these cultivars could be improved upon either through conventional or molecular breeding by coding with desirable genes. The cultivars which were adversely affected by BlCMV disease could so be improved genetically through appropriate gene introgression from the resistant cultivars.Keywords: Blackeye cowpea mosaic virus; disease incidence and severity; growth and yield; groundnu

Determination of some heavy metals in soil and edible vegetables grown in two different farms in Damaturu Metropolis, Yobe State, Nigeria

Vegetables comprise an important part of our daily foods that contribute some minerals and other nutrients to human body. Consumption of contaminated vegetables by heavy metals results in bioaccumulation of these harmful elements in the body. Therefore, this study is designed to examine the amount of heavy metal concentrations (Nickel, Copper, Cadmium and Zinc) in soil and edible parts of four vegetables namely Amaranthus hybridus (spinach), Hibiscus sabdariffa (roselle), Urena lobata (caesar weed) and Ceratotheca sesamoides (false sesame) grown in two farms. Transfer factor of heavy metals from soil to the plants was also evaluated. Samples were prepared and analysed using Atomic Absorption Spectrophotometry (AAS). The mean concentrations of all the vegetables in the both farms for Ni, Cu, Cd and Zn were obtained as 0.215, 2.341, 0.023 and 2.251 mg/Kg respectively. Whereas, the mean concentrations in the soils were 0.317, 7.560, 0.071 and 9.910 mg/Kg for Ni, Cu, Cd and Zn respectively. The levels of the above heavy metals in almost all the samples from those farms were below the maximum allowable limits recommended by WHO/FAO and therefore, they had acceptable conditions for human consumption. The exception was Ni which was slightly above the (0.1 mg/Kg) WHO/FAO permissible limit in the samples of both farms excluding Urena lobata of Custom Farm. In Bin Bukar, the trend of the transfer factor was in rank of Ni > Cd > Cu > Zn, whereas, in Custom Farm the transfer factor was sort as Cu > Ni > Cd. The highest Transfer Factor (TF) value was 1.464 found in Ceratotheca sesamoides for Ni in Bin Bukar Farm and 0.627 in Urena lobata for Cu in Custom Farm. The Transfer Factor values for Cd, Cu and Zn for the range of vegetables were not substantially high, except for Ni which the ratio was greater than one indicating that the plants have accumulated elements

Mapping child growth failure across low- and middle-income countries

Childhood malnutrition is associated with high morbidity and mortality globally1. Undernourished children are more likely to experience cognitive, physical, and metabolic developmental impairments that can lead to later cardiovascular disease, reduced intellectual ability and school attainment, and reduced economic productivity in adulthood2. Child growth failure (CGF), expressed as stunting, wasting, and underweight in children under five years of age (0�59 months), is a specific subset of undernutrition characterized by insufficient height or weight against age-specific growth reference standards3�5. The prevalence of stunting, wasting, or underweight in children under five is the proportion of children with a height-for-age, weight-for-height, or weight-for-age z-score, respectively, that is more than two standard deviations below the World Health Organization�s median growth reference standards for a healthy population6. Subnational estimates of CGF report substantial heterogeneity within countries, but are available primarily at the first administrative level (for example, states or provinces)7; the uneven geographical distribution of CGF has motivated further calls for assessments that can match the local scale of many public health programmes8. Building from our previous work mapping CGF in Africa9, here we provide the first, to our knowledge, mapped high-spatial-resolution estimates of CGF indicators from 2000 to 2017 across 105 low- and middle-income countries (LMICs), where 99 of affected children live1, aggregated to policy-relevant first and second (for example, districts or counties) administrative-level units and national levels. Despite remarkable declines over the study period, many LMICs remain far from the ambitious World Health Organization Global Nutrition Targets to reduce stunting by 40 and wasting to less than 5 by 2025. Large disparities in prevalence and progress exist across and within countries; our maps identify high-prevalence areas even within nations otherwise succeeding in reducing overall CGF prevalence. By highlighting where the highest-need populations reside, these geospatial estimates can support policy-makers in planning interventions that are adapted locally and in efficiently directing resources towards reducing CGF and its health implications. © 2020, The Author(s)

Global age-sex-specific fertility, mortality, healthy life expectancy (HALE), and population estimates in 204 countries and territories, 1950–2019: a comprehensive demographic analysis for the Global Burden of Disease Study 2019

Background: Accurate and up-to-date assessment of demographic metrics is crucial for understanding a wide range of social, economic, and public health issues that affect populations worldwide. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 produced updated and comprehensive demographic assessments of the key indicators of fertility, mortality, migration, and population for 204 countries and territories and selected subnational locations from 1950 to 2019. Methods: 8078 country-years of vital registration and sample registration data, 938 surveys, 349 censuses, and 238 other sources were identified and used to estimate age-specific fertility. Spatiotemporal Gaussian process regression (ST-GPR) was used to generate age-specific fertility rates for 5-year age groups between ages 15 and 49 years. With extensions to age groups 10–14 and 50–54 years, the total fertility rate (TFR) was then aggregated using the estimated age-specific fertility between ages 10 and 54 years. 7417 sources were used for under-5 mortality estimation and 7355 for adult mortality. ST-GPR was used to synthesise data sources after correction for known biases. Adult mortality was measured as the probability of death between ages 15 and 60 years based on vital registration, sample registration, and sibling histories, and was also estimated using ST-GPR. HIV-free life tables were then estimated using estimates of under-5 and adult mortality rates using a relational model life table system created for GBD, which closely tracks observed age-specific mortality rates from complete vital registration when available. Independent estimates of HIV-specific mortality generated by an epidemiological analysis of HIV prevalence surveys and antenatal clinic serosurveillance and other sources were incorporated into the estimates in countries with large epidemics. Annual and single-year age estimates of net migration and population for each country and territory were generated using a Bayesian hierarchical cohort component model that analysed estimated age-specific fertility and mortality rates along with 1250 censuses and 747 population registry years. We classified location-years into seven categories on the basis of the natural rate of increase in population (calculated by subtracting the crude death rate from the crude birth rate) and the net migration rate. We computed healthy life expectancy (HALE) using years lived with disability (YLDs) per capita, life tables, and standard demographic methods. Uncertainty was propagated throughout the demographic estimation process, including fertility, mortality, and population, with 1000 draw-level estimates produced for each metric. Findings: The global TFR decreased from 2•72 (95% uncertainty interval [UI] 2•66–2•79) in 2000 to 2•31 (2•17–2•46) in 2019. Global annual livebirths increased from 134•5 million (131•5–137•8) in 2000 to a peak of 139•6 million (133•0–146•9) in 2016. Global livebirths then declined to 135•3 million (127•2–144•1) in 2019. Of the 204 countries and territories included in this study, in 2019, 102 had a TFR lower than 2•1, which is considered a good approximation of replacement-level fertility. All countries in sub-Saharan Africa had TFRs above replacement level in 2019 and accounted for 27•1% (95% UI 26•4–27•8) of global livebirths. Global life expectancy at birth increased from 67•2 years (95% UI 66•8–67•6) in 2000 to 73•5 years (72•8–74•3) in 2019. The total number of deaths increased from 50•7 million (49•5–51•9) in 2000 to 56•5 million (53•7–59•2) in 2019. Under-5 deaths declined from 9•6 million (9•1–10•3) in 2000 to 5•0 million (4•3–6•0) in 2019. Global population increased by 25•7%, from 6•2 billion (6•0–6•3) in 2000 to 7•7 billion (7•5–8•0) in 2019. In 2019, 34 countries had negative natural rates of increase; in 17 of these, the population declined because immigration was not sufficient to counteract the negative rate of decline. Globally, HALE increased from 58•6 years (56•1–60•8) in 2000 to 63•5 years (60•8–66•1) in 2019. HALE increased in 202 of 204 countries and territories between 2000 and 2019. Interpretation: Over the past 20 years, fertility rates have been dropping steadily and life expectancy has been increasing, with few exceptions. Much of this change follows historical patterns linking social and economic determinants, such as those captured by the GBD Socio-demographic Index, with demographic outcomes. More recently, several countries have experienced a combination of low fertility and stagnating improvement in mortality rates, pushing more populations into the late stages of the demographic transition. Tracking demographic change and the emergence of new patterns will be essential for global health monitoring. Funding: Bill & Melinda Gates Foundation. © 2020 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 licens