224 research outputs found
The synthesis and pharmacological evaluation of quisqualic acid and some novel excitatory amino acid mimetics
L-Glutamic acid and L-aspartic acid are believed to be the principal initiators of excitatory synaptic neurotransmission in the mammalian central system. A number of molecules of either natural or synthetic origin have been identified as possessing agonist or antagonist properties at glutamate binding sites. One of the most potent agonist is quisqualic acid (69), and this thesis features two aspects of the synthetic organic chemistry and the pharmacology of quisqualic acid and some of its analogues
Relationship between School Location and Secondary Technical Students’ Acquisition of Knowledge-Based Skills in Cross River and Imo States of Nigeria
This paper investigated the influence of school location on students’ acquisition of knowledge-based skills in selected secondary technical schools in Cross River and Imo States of Nigeria. The objective of the study was to ascertain the influence of location (urban and rural) of secondary technical schools on students’ acquisition of knowledge-based skills (creative thinking, innovation, ICT and entrepreneurship skills) in the two states. A correlation design was adopted for the study. The population constituted 1328 SS II students drawn from 11 secondary technical schools across the two states out of which a stratified random sample of 330 was identified. Two research questions and two corresponding hypotheses were formulated to guide the study. A twelve-item multiple choice Students’ Aptitude Test on Skills Acquisition (SATSA), validated by five experts in instruments construction, and was administered on the sample for data collection. Data were analyzed with One Sample Test and ANOVA to ascertain the relationship between school locations and students’ acquisition of knowledge-based skills in the identified knowledge-based skill subjects. The paper recommended that principals and teachers of secondary technical schools should sustain and improve the performance of students in the two states. It further recommended that further investigations be conducted to ascertain students’ acquisition of knowledge-based skills irrespective of school location
Production and performance evaluation of biodiesel from Elaeis guineensis using natural snail shell-based heterogeneous catalyst: kinetics, modeling and optimisation by artificial neural network
This study presents an approach to produce biodiesel from Elaeis guineensis using natural heterogeneous catalysts derived from raw, calcined, and acid-activated forms of waste snail shells. The catalysts were thoroughly characterized using SEM, and process parameters were systematically evaluated during biodiesel production. Our results demonstrate a remarkable crop oil yield of 58.87%, with kinetic studies confirming second-order kinetics and activation energies of 43.70 kJ mol-1 and 45.70 kJ mol-1 for methylation and ethylation, respectively. SEM analysis identified the calcined catalyst as the most effective, exhibiting remarkable reusability for continuous reactions running up to five times. Moreover, the acid concentration from exhaust fumes yielded a low acid value (B100 0.0012 g dm-3), significantly lower than that of petroleum diesel, while the fuel properties and blends satisfied the ASTM standards. The sample-heavy metals were well within acceptable limits, confirming the quality and safety of the final product. Our modelling and optimization approach produced a remarkably low mean squared error (MSE) and a high coefficient of determination (R), providing strong evidence for the viability of this approach at an industrial scale. Our results represent a significant input in sustainable biodiesel production and underscore the enormous potential of natural heterogeneous catalysts derived from waste snail shells for achieving sustainable and environmentally friendly biodiesel production
A Review of Environmental Implications of Dredging Activities
Dredging is a global anthropogenic excavation activity of removing sediments from water bodies and depositing it elsewhere. It is a mixed blessing as it has both beneficial and adverse impacts. This paper is on a review of environmental implications of dredging. The objective of the paper is to review previous works by researchers on the environmental consequences of dredging. The method used is a review of academic/journal articles, internet materials, conference / workshop papers, textbooks, bulletins and publicly available materials on dredging activities. The results of the study revealed that previous authors whose works were reviewed have a convergent view that apart from the beneficial impacts of dredging (e.g. keeping waterways navigable, flood and storm protection and provision of materials for road construction and building), it has lots of adverse environmental impacts, including environmental pollution, erosion, widespread hydrological changes, reduction in the population of aquatic lives like destruction of fish spawning grounds and benthic organisms and resuspension of particulate matter column that has elevated levels of lead, copper, zinc and nickel in Phytoplankton. Recommendations of the study include: (1) establishment of environmental legislations and regulations for dredging operation; (2) use of green technology in dredging activities to minimize suspension of sediments and contamination/pollution of dredging environments; and (3) creation of awareness among dredging contractors, regulators and marine communities where dredging take place on the economic and ecological values of the marine ecosystems that are usually very sensitive, fragile and productive
Potentiality of Diethylamine as Agent of Deproteination and Deacetylation in the Extraction of Chitosan from Scylla serrata Shell
The potentiality of diethylamine as deproteination and deacetylation agent in the extraction of chitosan from Scylla serrata (giant mud crab) shell was investigated. The aim was to find an alternative agent to inorganic alkalis as possible replacement for use in the production of high quality chitosan with the right stability. Pretreatment of the shell was carried out and followed by demineralization using hydrochloric acid. Diethylamine was used for deproteination and deacetylation by modifying some published protocols. Moisture, ash, fat and protein contents of the extracts were determined using their respective standard methods. Fourier Transform Infrared (FTIR) technique was used for spectroscopic analysis. Scylla serrata shell was composed of 14.25% protein, 32.84% mineral (CaCO3), 31.52% chitin and 21.39% chitosan. Moisture, ash, fat and protein contents of chitin extracted from Scylla serrata shell were 2.35%, 3.03%, 1.79% and 3.85% respectively while those of chitosan were 1.65%, 3.84%, 0.53% and 2.80% respectively. Degree of deacetylation (DDA) and carbon to nitrogen ratio were 69.24% and 5.67 respectively. FTIR spectra of the extracted chitin and chitosan from Scylla serrata showed the presence of some active compounds of carbonyl, amide, amine and hydroxyl groups. However, CH3 waging along chain (952 cm-1), CO stretching at 1026 cm-1 and 1073 cm-1, and amide II band (1563 cm-1) were not found in the extracted chitin while HPO42- and amide III were also not found in the extracted chitosan. These moieties were present in the standard chitin and chitosan respectively. This study has shown that diethylamine (organic base) has great potential as agent of deproteination and deacetylation in the extraction of chitosan from Scylla serrata. Consequently, academic activity in the area of investigation of the stability of the extracted chitosan from Scylla serrata using diethylamine as deproteination and deacetylation agent is strongly recommended. Keywords: Diethylamine, deproteination, deacetylation, chitin and chitosan, Scylla serrata shell. DOI: 10.7176/CMR/12-7-07 Publication date:October 31st  2020
Data on physicochemical properties of borehole water and surface water treated using reverse osmosis [RO] and ultra-violet [UV] radiation water treatment techniques
This article present data on reverse osmosis (RO) and ultra-violet (UV) Radiation Water Treatment Techniques effects on the physiochemical properties of a treated surface wa- ter (SW) and borehole water (BHW). The water treatment study which was carried out in Omoku community in River State, lies with latitude 5 °13 ¹N and 5 °22 ¹N and longitude 6 °33 ¹E and 6 °42 ¹North West of the Niger Delta region of Nigeria, an area with over Nine hundred oil wells with over thirteen active oil fields and playing host to three multina- tional companies, due to these activities the water is highly contaminated and causing serious health challenges to the water consumer. Therefore, this research work focus on RO and UV water techniques by applying the physicochemical characteristics method and total Coliform count, with the mechanism to check the influence of both techniques on the pH, temperature, Turbidity, conductivity, Total suspended solids Total dissolved solids of the water for three different samples within the Omoku community. The experiment shows that RO treatment technique produces potable water with reduced mineral content in comparison to the UV treatment
Effects of Process Parameters on Vibration Frequency in Turning Operations of Perspex Material
Effects of process parameters on vibration frequency of Perspex round plastic bars was investigated experimentally under clamped - free (C - F) boundary condition during turning operation. Mathematical models were developed using Taguchi L9 orthogonal array design. Spindle speed (V), feed rate (f), and depth of cut (d) were selected as input variables in order to predict the effects of vibration frequency on the work-piece. Nine samples were run in a CNC lathe machine, and each of the experimental result was measured using DTO 32105 frequency analyser and a MXC-1600 digital frequency counter. A minimum vibration frequency of 104.8 Hz was obtained at a cutting speed of 320 m/min, feed rate 0.05 min/rev and at a depth of cut of 0.5 mm. The mathematical model developed shows the accuracy of predicting the vibration frequency to be 99.5% and the various combinations of parameters that results in the minimum vibration frequency were determined. Obtained optimum input parameters for vibration frequency indicated that production operations of Perspex round plastic bars could be enhanc
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Factors Associated With Pulmonary Tuberculosis-HIV Co-Infection in Treatment-Naive Adults in Jos, North Central Nigeria
Background: Co-infection with tuberculosis and human immunodeficiency virus (TB-HIV) remains a major global health problem, with about 1.1 million new cases of TB in HIV-positive persons reported in 2011; 79% of the reported cases were amongst patients living in Africa. Advanced immune suppression remains the most important risk factor for tuberculosis in those with HIV, but epidemiological and clinical factors have also been identified. We sought to determine the prevalence and factors associated with pulmonary tuberculosis (PTB) in antiretroviral therapy (ART)- naive HIV-infected patients seeking HIV care services at a tertiary health facility in North Central Nigeria. Methods: We compared clinical and laboratory data for 218 HIV-1 positive adults with and without a diagnosis of pulmonary tuberculosis. Results from univariate analyses informed the selection of predictors to conduct multivariate analysis to determine which factors were associated with presence of PTB-HIV co-infection. Results: The prevalence of PTB-HIV co-infection in the evaluated cohort was 9.6%. Lower CD4+ cell count and the presence of oropharyngeal candidiasis were independently associated with PTB-HIV co-infection. CD4+ cell count was strongly associated with PTB-HIV co-infection (p=0.002) with the odds of co-infection reduced by 85% in those with a CD4+ cell count >100 cells/mm3 compared to those with <100 cells/ mm3. There was a strong association between oropharyngeal candidiasis and PTB-HIV co-infection, where the odds of co-infection are about 4.5 times higher in those with oropharyngeal candidiasis than those without candidiasis (p=0.008). Conclusion: PTB was prevalent among HIV patients seeking care in our setting. Severe immune suppression and oropharyngeal candidiasis were associated with PTB-HIV co-infection in our patients at presentation. Potential implications for severe immune suppression and advanced HIV disease are a poor clinical outcome and further spread of PTB. Strategies to encourage the early diagnosis of both HIV and TB should be considere
Early management of adult traumatic spinal cord injury in patients with polytrauma: a consensus and clinical recommendations jointly developed by the World Society of Emergency Surgery (WSES) & the European Association of Neurosurgical Societies (EANS)
Background: The early management of polytrauma patients with traumatic spinal cord injury (tSCI) is a major challenge. Sparse data is available to provide optimal care in this scenario and worldwide variability in clinical practice has been documented in recent studies. Methods: A multidisciplinary consensus panel of physicians selected for their established clinical and scientific expertise in the acute management of tSCI polytrauma patients with different specializations was established. The World Society of Emergency Surgery (WSES) and the European Association of Neurosurgical Societies (EANS) endorsed the consensus, and a modified Delphi approach was adopted. Results: A total of 17 statements were proposed and discussed. A consensus was reached generating 17 recommendations (16 strong and 1 weak). Conclusions: This consensus provides practical recommendations to support a clinician’s decision making in the management of tSCI polytrauma patients
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