169 research outputs found
A Model for Determining the Effect of Irregular Power Supply on Machining Foundry Products in a Developing Economy
In this paper, profit is maximized (or production cost is minimized) by developing an Integer programming (IP) model to determine, at a given respective unit cost, optimal numbers of outputs obtainable per production cycle (time) using public electricity generated from national grids and alternate electricity from generators subject to production output capacity or demand constraint. The results obtained showed that production cycle time has a great impact on the determination of optimal outputs for the respective conditions. Also, increase in cost of public electricity per unit product has an upper limit beyond which it has negative effect on the profitability. The results served as determinant factors for production industry in establishing the level of outputs that sustained the profitability by providing optimal cost of public electricity to operate without having any effect on the profit, at a given cycle time. Keywords— Constraint, cycle time, integer programming, optimal number, mode
Proximate Composition and Metabolizable Energy of Some Commercial Poultry Feeds Available in Abuja, Nigeria
Poultry feeds are prepared to contain all the nutrients in their right proportions necessary for good health, proper growth and egg production of the chicken. This study was undertaken to determine the proximate composition and variations of nutrient in some commercial poultry feeds sold in Abuja, Nigeria. Seven poultry feed brands in their various ratios were subjected to proximate analysis using standard methods. The results of the analysis revealed that the poultry feeds had proximate composition ranging from 6.58 ± 0.02 - 10.88 ± 0.19 % moisture content, 6.03 ± 0.16 - 14.78 ± 0.73 % ash content, 9.98 ± 0.81 - 20.05 ± 0.08 % crude lipid, 3.57 ± 0.11 - 14.77 ± 0.14 % crude fiber, 16.55 ± 0.07 % - 34.01 ± 0.09 % crude protein, 26.28 ± 1.80 % - 48.21 ± 2.07 % carbohydrate and 2971.48 ± 65.44 - 3686.18 ± 29.08 Kcal/kg metabolizable energy. Generally, there were differences in the proximate composition of the poultry feed brands analyzed, however, the poultry feeds have optimum nutrients in their feeds which meet most of the requirements recommended by SON and NRC. The moisture contents in all the feeds were within the recommended value of not more than 12 % while the mean values obtained in crude lipid were all higher than the maximum recommended requirements in poultry feeds
MODELLING AND OPTIMIZATION OF COEFFICIENT OF PERFORMANCE OF LOWER TEMPERATURE CYCLE OF TWO-STEP REFRIGERATION SYSTEMS
The coefficient of performance (COP) of a single-stage refrigeration system is low, thus there is a need for two-step refrigeration systems when there is a desire to have an evaporator temperature that is below -25 oC. The COP of the lower temperature cycle of the two-step refrigeration systems is a function of the COP of the refrigeration systems.This research aimed at optimizing COP of the lower temperature cycle of two-step refrigeration systems using eco-friendly refrigerants.Thermodynamic analysis of these refrigeration systems was performed by varying seven operating parameters. R-134a was used in the high-temperature cycle (HTC) and R-23 was used in the low-temperature cycle (LTC). The coefficient of performance of the lower temperature cycle (COP.REF[LTC]) of the refrigeration systems was optimized using Half Factorial Design of Design-Expert 12.0.1. The influence of the condensing temperature (TC,HTC),evaporating temperature (TE,HTC), cascade temperature difference (∆TCAS,DIFF), evaporating temperature (TE,LTC), superheating temperature (TSUP,LTC), sub-cooling temperature (TSUB,LTC), and refrigerant mass Flow rate (ṁHTC)was investigated on the values of COP.REF[LTC] of the refrigeration systems. The highest value of COP.REF[LTC] (18.1) was obtained under optimum conditions of the 30 TC,HTCoC , -40 TE,HTCoC, 0 ∆TCAS,DIFFoC, -50 TE,LTCoC, 0 TSUP,LTCoC, 20 TSUB,LTCoC and 0.01 ṁHTC kg/s.The study revealed that all the factors having interaction with TC[HTC] and TE[HTC] have a great influence on the value of COP.REF[LTC
Spatial analysis of tuberculosis and risk factors at the lowest administrative level in Nigeria
BACKGROUNDFew studies have utilized modern techniques of spatial data analysis to understand the distribution of tuberculosis (TB) and its possible predictors. In 2013, an estimated 9 million new TB cases and 1.5 million deaths occurred worldwide, out of which 360,000 deaths were HIV related.
AIMTo assist in planning key interventions for the control of TB at a sub-national level, the studysought to explore the spatial distribution of TB and associated risk factors at the lowest administrative level in Nigeria.
METHODOLOGYThis was an ecological study carried out using number of notified TB cases for the 774 Local Government Areas (LGAs) in 2013. Bayesian spatial regression analysis was conducted to identify high-risk clusters of the disease and to assess associated factors .
RESULTSAnalysis revealed that TB was significantly clustered in 138 (17%) LGAs. Significant associations were found with household size, urban residence, access to transportation, population density, number of TB diagnostic services. Other predictors, including a composite index of socioeconomic status, living in a single room, number of TB treatment centres, and total health facilities in the LGA were not significantly associated with TB incidence.
CONCLUSIONThe study identified LGAs with elevated risk as well as significant factors associated with TB. This information can assist policymakers in rationally planning targeted specific interventions with the potential to effectively control TB in the country
How Effective is the Treatment of Locally Advanced and Metastatic Breast Cancer in Developing Centres?: A Retrospective Review
BACKGROUND: The use of chemotherapy in advanced metastatic breast cancer remains a subject of controversy. The thought of MicKinnon et al (early 1950s) that the course of breast cancer was unaffected by chemotherapy has been refuted by results of treatment in the developed countries. The poor result of treatment in developing centres still compares with prechemotherapy era. Consequently, The McKinnon’s thought may still lurk. We compared the survival of chemotherapy treated with chemotherapy untreated cancer of breast patients.METHOD: Records of breast cancer patients who presented and died between January 2010 and May 2014 were reviewed. The primary outcome was overall survival. Records of patients that received chemotherapy with or without other tumor directed specific therapy were compared with records of patients who did not receive any tumor directed therapy.RESULT: Thirty-one patients received chemotherapy while 25 patients did not. All were females, more than 90% were of the patients had advanced or metastatic disease. Treatments were not biologically directed and treatment plans were largely compromised and suboptimal. The overall mean survival was 19.2 ±9.2 months, and the median duration was 17.5 months(range 6-44months). The overall survival was not statistically different between the two groups (p= 0.230, unequal variance assumed). The objective of using neoadjuvant chemotherapy for fungating lesions was not achieved.CONCLUSION: In advanced and metastatic breast cancer, outcomes of patients who receive suboptimal regimen of cytotoxic chemotherapy do not differ from chemotherapy untreated patients.KEYWORDS: breast cancer, suboptimal treatment, untreated, chemotherap
Genetic diversity assessment of sorghum (Sorghum bicolor (L.) Moench) accessions using single nucleotide polymorphism markers
Sorghum (Sorghum bicolor (L.) Moench) is an important resource to the national economy and it is essential to assess the genetic diversity in existing sorghum germplasm for better conservation, utilization and crop improvement. The aim of this study was to evaluate the level of genetic diversity within and among sorghum germplasms collected from diverse institutes in Nigeria and Mali using Single Nucleotide Polymorphic markers. Genetic diversity among the germplasm was low with an average polymorphism information content value of 0.24. Analysis of Molecular Variation revealed 6%variation amonggermplasmand 94%withingermplasms.Dendrogramrevealed threegroupsof clusteringwhich indicatevariationswithinthegermplasms. Privatealleles identified inthesorghum accessions from National Center for Genetic Resources and Biotechnology, Ibadan, Nigeria and International Crop Research Institute for the Semi-Arid Tropics, Kano, Nigeria shows their prospect for sorghum improvement and discovery of new agronomic traits. The presence of private alleles and genetic variation within the germplasms indicates that the accessions are valuable resources for future breeding programs
Exploring computational approaches to design mRNA Vaccine against vaccinia and Mpox viruses
Background: Messenger RNA (mRNA) vaccines emerged as a powerful tool in the fight against infections. Unlike traditional vaccines, this unique type of vaccine elicits robust and persistent innate and humoral immune response with a unique host cell‐mediated pathogen gene expression and antigen presentation. Methods: This offers a novel approach to combat poxviridae infections. From the genome of vaccinia and Mpox viruses, three key genes (E8L, E7R, and H3L) responsible for virus attachment and virulence were selected and employed for designing the candidate mRNA vaccine against vaccinia and Mpox viral infection. Various bioinformatics tools were employed to generate (B cell, CTL, and HTL) epitopes, of which 28 antigenic and immunogenic epitopes were selected and are linked to form the mRNA vaccine construct. Additional components, including a 5′ cap, 5′ UTR, adjuvant, 3′ UTR, and poly(A) tail, were incorporated to enhance stability and effectiveness. Safety measures such as testing for human homology and in silico immune simulations were implemented to avoid autoimmunity and to mimics the immune response of human host to the designed mRNA vaccine, respectively. The mRNA vaccine's binding affinity was evaluated by docking it with TLR‐2, TLR‐3, TLR‐4, and TLR‐9 receptors which are subsequently followed by molecular dynamics simulations for the highest binding one to predict the stability of the binding complex. Results: With a 73% population coverage, the mRNA vaccine looks promising, boasting a molecular weight of 198 kDa and a molecular formula of C8901H13609N2431O2611S48 and it is said to be antigenic, nontoxic and nonallergic, making it safe and effective in preventing infections with Mpox and vaccinia viruses, in comparison with other insilico‐designed vaccine for vaccinia and Mpox viruses. Conclusions: However, further validation through in vivo and in vitro techniques is underway to fully assess its potential
Determination of cross-sectional void fraction in a two-phase water flow through a PVC pipe
Gamma ray transmission method for void faction measurement studies is in rare use
in Nigeria, especially in industries and research.The study used this method to determine the
cross-sectional void fraction of two-phase water flow through a Polyvinyl chloride (PVC)
pipechannel.The gamma-ray counts transmitted through the water pipe were recorded and used
to calculate the void fraction using a semi-empirical approach. Void ratio values varying from
0.171 – 0.036 were obtained for water flow rates ranging between 0.5gal/min - 4.0gal/min at
estimated constant air flow rate. Conclusively, the experimental results compared well with
Chisholm theoretical model predictions of void ratio applicable to horizontal flow.The use of
two or more theoretical model predictions is recommended for further comparative study with
experimental process. Also, more use of gamma ray transmission method should be
encouraged
Astrovirus replication in human intestinal enteroids reveals multi-cellular tropism and an intricate host innate immune landscape.
Human astroviruses (HAstV) are understudied positive-strand RNA viruses that cause gastroenteritis mostly in children and the elderly. Three clades of astroviruses, classic, MLB-type and VA-type have been reported in humans. One limitation towards a better understanding of these viruses has been the lack of a physiologically relevant cell culture model that supports growth of all clades of HAstV. Herein, we demonstrate infection of HAstV strains belonging to all three clades in epithelium-only human intestinal enteroids (HIE) isolated from biopsy-derived intestinal crypts. A detailed investigation of infection of VA1, a member of the non-canonical HAstV-VA/HMO clade, showed robust replication in HIE derived from different patients and from different intestinal regions independent of the cellular differentiation status. Flow cytometry and immunofluorescence analysis revealed that VA1 infects several cell types, including intestinal progenitor cells and mature enterocytes, in HIE cultures. RNA profiling of VA1-infected HIE uncovered that the host response to infection is dominated by interferon (IFN)-mediated innate immune responses. A comparison of the antiviral host response in non-transformed HIE and transformed human colon carcinoma Caco-2 cells highlighted significant differences between these cells, including an increased magnitude of the response in HIE. Additional studies confirmed the sensitivity of VA1 to exogenous IFNs, and indicated that the endogenous IFN response of HIE to curtail the growth of strains from all three clades. Genotypic variation in the permissiveness of different HIE lines to HAstV could be overcome by pharmacologic inhibition of JAK/STAT signaling. Collectively, our data identify HIE as a universal infection model for HAstV and an improved model of the intestinal epithelium to investigate enteric virus-host interactions
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