Olukayode Adeyemo, Sunday O. Adewale, A. Oladipo, M. A. Omoloye
Asthma is a condition in which your airways narrow and swell and may produce extra mucus. In this study, an improved mathematical model of asthma which includes infected class not detected, infected detected class and recovered (relieved) class was formulated. The model exhibits two equilibrium, namely disease free equilibrium and endemic equilibrium. The analysis of positivity and boundedness of solutions showed that the model is epidemiologically well pose d. Simulation results showed that when pollutants are discharged into the environment at a constant rate, the asthma disease cases also increase in the population due to the fact that the interaction rate of both susceptible and infected undetected with pollutants in creases.Finally, asthma can be control by restricting the smokers from the population and the rate of release of pollutants into the environment.
{"title":"Analysis of mathematical model for asthma caused by the effects of environmental pollution","authors":"Olukayode Adeyemo, Sunday O. Adewale, A. Oladipo, M. A. Omoloye","doi":"10.4314/swj.v19i1.6","DOIUrl":"https://doi.org/10.4314/swj.v19i1.6","url":null,"abstract":"Asthma is a condition in which your airways narrow and swell and may produce extra mucus. In this study, an improved mathematical model of asthma which includes infected class not detected, infected detected class and recovered (relieved) class was formulated. The model exhibits two equilibrium, namely disease free equilibrium and endemic equilibrium. The analysis of positivity and boundedness of solutions showed that the model is epidemiologically well pose d. Simulation results showed that when pollutants are discharged into the environment at a constant rate, the asthma disease cases also increase in the population due to the fact that the interaction rate of both susceptible and infected undetected with pollutants in creases.Finally, asthma can be control by restricting the smokers from the population and the rate of release of pollutants into the environment.","PeriodicalId":21583,"journal":{"name":"Science World Journal","volume":"11 15","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141021255","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A.R. Uba, H. U. Jamo, U. I. Ismail, F.U. Musa, S.H. Gwadabe
The high energy demand with the negative environmental impacts of using fossil fuel for energy generations raised question on over dependability on it for sustainable economic growth. Biodiesel tend to be one of the renewable alternative solutions towards the above problems. Biodiesel can be produced through various methods such as transesterification, micro emulsion and pyrolysis The heterogeneous catalytic performance of Palm Oil Fuel Ash (POFA) in the production of biodiesel via transesterification of jatropha oil was investigated. The morphological and chemical properties of POFA were studied using Scanning Electron Microscopy (SEM) and X-ray Fluoroscopy (XRF) respectively. The crude Jatropha oil was transesterified and 0.1 wt%, 0.2 wt%, 0.3wt%, 0.4wt% and 0.5wt% of POFA were used as heterogeneous catalyst. Fourier Transform Infrared (FTIR) has been used to determine the functional group of the samples. SEM indicates the presence porous structure, texture and irregular shape on POFA while XRF shows that it comprises mainly of SiO2 (79.45 %). The maximum percentage of biodiesel yield was 92.30% at the application of 0.2wt% POFA. This shows that POFA can be used as a heterogeneous catalyst in the production of biodiesel.
{"title":"The determination of heterogeneous catalytic performance of Palm Oil Fuel Ash (POFA) in the production of biodiesel via transesterification of Jatropha oil","authors":"A.R. Uba, H. U. Jamo, U. I. Ismail, F.U. Musa, S.H. Gwadabe","doi":"10.4314/swj.v19i1.3","DOIUrl":"https://doi.org/10.4314/swj.v19i1.3","url":null,"abstract":"The high energy demand with the negative environmental impacts of using fossil fuel for energy generations raised question on over dependability on it for sustainable economic growth. Biodiesel tend to be one of the renewable alternative solutions towards the above problems. Biodiesel can be produced through various methods such as transesterification, micro emulsion and pyrolysis The heterogeneous catalytic performance of Palm Oil Fuel Ash (POFA) in the production of biodiesel via transesterification of jatropha oil was investigated. The morphological and chemical properties of POFA were studied using Scanning Electron Microscopy (SEM) and X-ray Fluoroscopy (XRF) respectively. The crude Jatropha oil was transesterified and 0.1 wt%, 0.2 wt%, 0.3wt%, 0.4wt% and 0.5wt% of POFA were used as heterogeneous catalyst. Fourier Transform Infrared (FTIR) has been used to determine the functional group of the samples. SEM indicates the presence porous structure, texture and irregular shape on POFA while XRF shows that it comprises mainly of SiO2 (79.45 %). The maximum percentage of biodiesel yield was 92.30% at the application of 0.2wt% POFA. This shows that POFA can be used as a heterogeneous catalyst in the production of biodiesel.","PeriodicalId":21583,"journal":{"name":"Science World Journal","volume":"11 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141021266","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Biosurfactants aid in bioremediation by improving the bioavailability of hydrocarbon contaminants. The objective of this work was to isolate, enumerate and identify bacteria and fungi for their biosurfactant production potential in the atmosphere of five petroleum stations at Tanke, Ilorin, Kwara State, Nigeria using appropriate, standard microbiological methods (haemolysis test, emulsification index test, drop collapse test and oil displacement test). Fourteen bacteria and ten fungi were isolated in this study. The bacterial isolates belong to the genus Bacillus, Corynebacterium, Micrococcus, Staphylococcus, Listeria, Clostridium. The fungal isolates are of the genus Neurospora, Curvularia, Aspergillus, Fusarium, Rhizopus, Cladosporium, Colletotrichum, Sclerotinia. The mean number of bacteria counted during the sampling ranged from 3.48±1.15*102 CFU to 4.82 ±1.69*102 CFU, with petrol station 4 having the highest bacteria count (2.41*102 CFU) and petrol station 3 having the lowest bacteria count (1.74*102 CFU). The mean fungal count ranged from 7±3.7 CFU to 8.6±4.7 *102 CFU, with petrol station 4 having the highest fungal count (4.3 *10 CFU) and petrol station 3 having the lowest fungal count (3.4*10 CFU). Bacillus species showed promise of biosurfactant production after screening. Aspergillus fumigatus was the most prevalent fungus isolated (24%) while Staphylococcus epidermidis was the most prevalent bacterium isolated (11%). Some of these organisms are known opportunistic pathogens therefore, improved ventilation and sanitation of the petrol stations should be carried out to reduce the microbial load in the air. Also, bacteria that produce biosurfactant can be isolated from air of gas stations.
{"title":"Biosurfactant production potentials of microorganisms isolated from atmosphere of five petroleum stations at Tanke, Ilorin, Kwara State, Nigeria","authors":"D. Adetitun, P.K. Oni, R. Tomilayo","doi":"10.4314/swj.v19i1.14","DOIUrl":"https://doi.org/10.4314/swj.v19i1.14","url":null,"abstract":"Biosurfactants aid in bioremediation by improving the bioavailability of hydrocarbon contaminants. The objective of this work was to isolate, enumerate and identify bacteria and fungi for their biosurfactant production potential in the atmosphere of five petroleum stations at Tanke, Ilorin, Kwara State, Nigeria using appropriate, standard microbiological methods (haemolysis test, emulsification index test, drop collapse test and oil displacement test). Fourteen bacteria and ten fungi were isolated in this study. The bacterial isolates belong to the genus Bacillus, Corynebacterium, Micrococcus, Staphylococcus, Listeria, Clostridium. The fungal isolates are of the genus Neurospora, Curvularia, Aspergillus, Fusarium, Rhizopus, Cladosporium, Colletotrichum, Sclerotinia. The mean number of bacteria counted during the sampling ranged from 3.48±1.15*102 CFU to 4.82 ±1.69*102 CFU, with petrol station 4 having the highest bacteria count (2.41*102 CFU) and petrol station 3 having the lowest bacteria count (1.74*102 CFU). The mean fungal count ranged from 7±3.7 CFU to 8.6±4.7 *102 CFU, with petrol station 4 having the highest fungal count (4.3 *10 CFU) and petrol station 3 having the lowest fungal count (3.4*10 CFU). Bacillus species showed promise of biosurfactant production after screening. Aspergillus fumigatus was the most prevalent fungus isolated (24%) while Staphylococcus epidermidis was the most prevalent bacterium isolated (11%). Some of these organisms are known opportunistic pathogens therefore, improved ventilation and sanitation of the petrol stations should be carried out to reduce the microbial load in the air. Also, bacteria that produce biosurfactant can be isolated from air of gas stations.","PeriodicalId":21583,"journal":{"name":"Science World Journal","volume":"42 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141018262","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Invasion of urinary tract by pathogens can lead to urinary tract infections (UTIs). Asymptomatic UTI is characterized by bacteriuria that is not accompanied by typical urinary tract symptoms, which often goes unnoticed until it has become serious. Early detection, accurate diagnosis and appropriate selection of antibiotics can improve prognosis, prevent chonic progression of renal disease and increase treatment success. Students in tertiary institutions may become at risk of UTIs due to overcrowding, poor hygiene practices and sexual activities. This study was focused on assessing the prevalence and antibiograms of uropathogens causing asymptomatic bacteriuria among university students. Mid-stream urine samples of early morning were obtained from 201 students of Ahmadu Bello University, Zaria, Nigeria. Structured questionnaires were administered to the students to collect their socio-demographic information and exposure to certain risk factors. The samples were inoculated onto sterile Xylose Lysine Deoxycholate agar and Centrimide agar plates, incubated at 37°C for 24 h. The pure isolates were identified by cultural morphology, Gram staining and biochemical characterization, and were further challenged with selected antibiotics. Bacterial uropathogens identified were Citrobacter spp and Pseudomonas aeruginosa with prevalence of 10(5.0%) and 5(2.5%) respectively. The females were more infected than the males. The oldest students of 25-27 years and 28-30 years old had the highest occurrences of Citrobacter spp and Pseudomonas aeruginosa respectively. All the cases of Citrobacter spp were found among single students, but higher occurrence of Pseudomonas aeruginosa was found among the married subjects. Students who have spent the longest time (i.e. in their 6th year) in school had the highest infection with the uropathogens. Students that stayed off-campus, share public latrines, drink sachet water and claimed to have one sex partner each were found with higher occurrences of asymptomatic infections. The antibiotic susceptibility test showed that all the isolates were most susceptible to Ciprofloxacin, Ofloxacin, and Pefloxacin, and resistant to Septrin. However, isolates of Pseudomonas aeruginosa were resistant to Streptomycin. Students should be well-informed about the risks associated with poor hygiene, over-crowding and unhealthy sexual habits. Routine checkups will help to prevent asymptomatic UTIs from developing into severe infections or complications.
{"title":"Uropathogens and their antibiograms in asymptomatic bacteriuria among university students in Zaria, Nigeria","authors":"Elizabeth Opawoye, Victor Markus, H. Bishop","doi":"10.4314/swj.v19i1.21","DOIUrl":"https://doi.org/10.4314/swj.v19i1.21","url":null,"abstract":"Invasion of urinary tract by pathogens can lead to urinary tract infections (UTIs). Asymptomatic UTI is characterized by bacteriuria that is not accompanied by typical urinary tract symptoms, which often goes unnoticed until it has become serious. Early detection, accurate diagnosis and appropriate selection of antibiotics can improve prognosis, prevent chonic progression of renal disease and increase treatment success. Students in tertiary institutions may become at risk of UTIs due to overcrowding, poor hygiene practices and sexual activities. This study was focused on assessing the prevalence and antibiograms of uropathogens causing asymptomatic bacteriuria among university students. Mid-stream urine samples of early morning were obtained from 201 students of Ahmadu Bello University, Zaria, Nigeria. Structured questionnaires were administered to the students to collect their socio-demographic information and exposure to certain risk factors. The samples were inoculated onto sterile Xylose Lysine Deoxycholate agar and Centrimide agar plates, incubated at 37°C for 24 h. The pure isolates were identified by cultural morphology, Gram staining and biochemical characterization, and were further challenged with selected antibiotics. Bacterial uropathogens identified were Citrobacter spp and Pseudomonas aeruginosa with prevalence of 10(5.0%) and 5(2.5%) respectively. The females were more infected than the males. The oldest students of 25-27 years and 28-30 years old had the highest occurrences of Citrobacter spp and Pseudomonas aeruginosa respectively. All the cases of Citrobacter spp were found among single students, but higher occurrence of Pseudomonas aeruginosa was found among the married subjects. Students who have spent the longest time (i.e. in their 6th year) in school had the highest infection with the uropathogens. Students that stayed off-campus, share public latrines, drink sachet water and claimed to have one sex partner each were found with higher occurrences of asymptomatic infections. The antibiotic susceptibility test showed that all the isolates were most susceptible to Ciprofloxacin, Ofloxacin, and Pefloxacin, and resistant to Septrin. However, isolates of Pseudomonas aeruginosa were resistant to Streptomycin. Students should be well-informed about the risks associated with poor hygiene, over-crowding and unhealthy sexual habits. Routine checkups will help to prevent asymptomatic UTIs from developing into severe infections or complications.","PeriodicalId":21583,"journal":{"name":"Science World Journal","volume":"7 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141021823","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The potential of using microorganisms as biological sources of industrially economic enzymes has stimulated interest in the exploitation of extracellular enzymatic activity in several microorganisms. The aim of this research is to assess the cellulose degrading potentials of two microorganisms, Aspergillus oryzae and Streptomyces griseus using cellulose Congo red agar media. Soil sample collected from waste dump was serially diluted and inoculated in starch casein agar and SDA to isolate S. griseus and A. oryzae respectively. To assess their potentials to utilize cellulose, each of the two microorganisms was inoculated on cellulose Congo-red media and incubated at 30 ºC for 7days. A zone of clearing around the colonies after incubation confirms the secretion of extracellular cellulase, and was used as an indication for cellulose utilization. The zone of clearing was measured with a meter rule. In the results obtained, both microorganisms demonstrated cellulose utilization ability with Aspergillus oryzae showing a zone of clearing of 30.50 ± 0.50 mm while Streptomyces griseus showed a wider zone of clearing of 60.00 ± 1.00 mm. The results indicate that both microorganisms can be potent producers of the enzyme cellulase, with Streptomyces griseus having a higher cellulase-producing ability.
{"title":"Cellulolytic potentials of aspergillus oryzae and streptomyces griseus isolated from waste dump soil in Nile University Of Nigeria, Abuja","authors":"G.G. Ezeagu, M. Fadayomi, U.S. Rikiji","doi":"10.4314/swj.v19i1.25","DOIUrl":"https://doi.org/10.4314/swj.v19i1.25","url":null,"abstract":"The potential of using microorganisms as biological sources of industrially economic enzymes has stimulated interest in the exploitation of extracellular enzymatic activity in several microorganisms. The aim of this research is to assess the cellulose degrading potentials of two microorganisms, Aspergillus oryzae and Streptomyces griseus using cellulose Congo red agar media. Soil sample collected from waste dump was serially diluted and inoculated in starch casein agar and SDA to isolate S. griseus and A. oryzae respectively. To assess their potentials to utilize cellulose, each of the two microorganisms was inoculated on cellulose Congo-red media and incubated at 30 ºC for 7days. A zone of clearing around the colonies after incubation confirms the secretion of extracellular cellulase, and was used as an indication for cellulose utilization. The zone of clearing was measured with a meter rule. In the results obtained, both microorganisms demonstrated cellulose utilization ability with Aspergillus oryzae showing a zone of clearing of 30.50 ± 0.50 mm while Streptomyces griseus showed a wider zone of clearing of 60.00 ± 1.00 mm. The results indicate that both microorganisms can be potent producers of the enzyme cellulase, with Streptomyces griseus having a higher cellulase-producing ability.","PeriodicalId":21583,"journal":{"name":"Science World Journal","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141018636","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
CdTe based solar cells have proved to be the most successful thin film PV solar cells with their full industrial production. However, the needed improvement in output efficiency of these cells is constrained by major issues such the poor understanding of the ternary CdSxTe1-x interlayer, formed at the CdS-CdTe interface. While it is believed to have both beneficial and negative effects on the cell performance, its exact mechanism and extent are not fully explored. In this work, the AMPS-1D software was used to model this interlayer, using several of its variables such as thickness, bandgap as well as the thickness of the bounding CdS layer. Results show that the interlayer thickness reduces cell performance, through Jsc, Voc, FF and J-V curves, with best efficiencies of 17.892% (Jsc=27.043mA/cm3, Voc=0.871V, FF=0.8) obtained at zero thickness, falling down by nearly 20% at CdSxT1-x thickness of 100nm. As the bandgap is varied, maximum cell performance of 17.85% (Jsc=27.76, Voc=0.91V and FF=0.81) was found at 1.7eV. Similarly, increasing CdS thickness also reduced cell performance, by reducing the quantum efficiency. The results indicate that if the CdSxTe1-x layer has a thickness of up to 100nm, and a bandgap of around 1.7eV, then cell efficiencies of around 18% were feasible even for ultra-thin CdTe layers of 1μm.
{"title":"Assessing the effects and impacts of the CdSTe interlayer in the performance of the CdTe-CdS thin film solar cells through simulations","authors":"M. Aliyu","doi":"10.4314/swj.v19i1.31","DOIUrl":"https://doi.org/10.4314/swj.v19i1.31","url":null,"abstract":"CdTe based solar cells have proved to be the most successful thin film PV solar cells with their full industrial production. However, the needed improvement in output efficiency of these cells is constrained by major issues such the poor understanding of the ternary CdSxTe1-x interlayer, formed at the CdS-CdTe interface. While it is believed to have both beneficial and negative effects on the cell performance, its exact mechanism and extent are not fully explored. In this work, the AMPS-1D software was used to model this interlayer, using several of its variables such as thickness, bandgap as well as the thickness of the bounding CdS layer. Results show that the interlayer thickness reduces cell performance, through Jsc, Voc, FF and J-V curves, with best efficiencies of 17.892% (Jsc=27.043mA/cm3, Voc=0.871V, FF=0.8) obtained at zero thickness, falling down by nearly 20% at CdSxT1-x thickness of 100nm. As the bandgap is varied, maximum cell performance of 17.85% (Jsc=27.76, Voc=0.91V and FF=0.81) was found at 1.7eV. Similarly, increasing CdS thickness also reduced cell performance, by reducing the quantum efficiency. The results indicate that if the CdSxTe1-x layer has a thickness of up to 100nm, and a bandgap of around 1.7eV, then cell efficiencies of around 18% were feasible even for ultra-thin CdTe layers of 1μm.","PeriodicalId":21583,"journal":{"name":"Science World Journal","volume":"76 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141019442","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
F. Anslem, R.B. Oloyede, A.A. Kassim, A. Bashir, Z.S. Yahaya
Stability assessments are crucial in determining the shelf-life and quality of compounded pharmaceutical products. Folic acid, an essential B-vitamin, is widely used to prevent and treat folate deficiency-related conditions. However, because of patient-specific demands or customised dose requirements, compounded folic acid syrups are frequently used in pediatric patients. This study aims to examine the stability of compounded folic acid mixtures prepared with some commercially available vitamin syrups. Three commercially available vitamin syrups were utilized as compounding vehicles for folic acid tablets, ensuring a representative sample of products commonly used in compounding practices in hospitals when conventional compounding vehicles are not available. The compounded folic acid mixtures were stored under ambient (21- 25 ºC) and refrigerated conditions (2-8 ºC), to simulate real-life scenarios, and tested using parameters such as, organoleptic characteristics, sedimentation rate, pH, microbial growth and drug content determination at day 7, 14 and 30. The extemporaneous preparations of the compounded folic acid in vitamin syrups generally maintained their physical characteristics over the 30-day study period. However, there was either decrease in folic acid concentration or microbial contamination of the preparations at day 7. Therefore, folic acid compounded in vitamin syrups are generally stable for less than seven days. The data obtained will aid healthcare professionals and compounding pharmacies in decision making concerning the choice of vehicle, compounding practices and strategies to ensure the preparation of wholesome extemporaneous products.
{"title":"Insights into folic acid mixtures compounded with commercially available vitamin syrups","authors":"F. Anslem, R.B. Oloyede, A.A. Kassim, A. Bashir, Z.S. Yahaya","doi":"10.4314/swj.v19i1.5","DOIUrl":"https://doi.org/10.4314/swj.v19i1.5","url":null,"abstract":"Stability assessments are crucial in determining the shelf-life and quality of compounded pharmaceutical products. Folic acid, an essential B-vitamin, is widely used to prevent and treat folate deficiency-related conditions. However, because of patient-specific demands or customised dose requirements, compounded folic acid syrups are frequently used in pediatric patients. This study aims to examine the stability of compounded folic acid mixtures prepared with some commercially available vitamin syrups. Three commercially available vitamin syrups were utilized as compounding vehicles for folic acid tablets, ensuring a representative sample of products commonly used in compounding practices in hospitals when conventional compounding vehicles are not available. The compounded folic acid mixtures were stored under ambient (21- 25 ºC) and refrigerated conditions (2-8 ºC), to simulate real-life scenarios, and tested using parameters such as, organoleptic characteristics, sedimentation rate, pH, microbial growth and drug content determination at day 7, 14 and 30. The extemporaneous preparations of the compounded folic acid in vitamin syrups generally maintained their physical characteristics over the 30-day study period. However, there was either decrease in folic acid concentration or microbial contamination of the preparations at day 7. Therefore, folic acid compounded in vitamin syrups are generally stable for less than seven days. The data obtained will aid healthcare professionals and compounding pharmacies in decision making concerning the choice of vehicle, compounding practices and strategies to ensure the preparation of wholesome extemporaneous products.","PeriodicalId":21583,"journal":{"name":"Science World Journal","volume":"33 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141018135","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Ochigbo, Alfred Obukohwo Obar, M.A.T. Suleiman, A.S. Kovo
Graphene oxide (GO) was synthesized from graphite via a modified Hummer's method, followed by thermal and chemical reductions to produce reduced graphene oxide (RGO) samples at various temperatures. A suite of characterization techniques including Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDS), UV-Visible Spectroscopy, thermogravimetric analysis (TGA), X-ray diffraction (XRD), and Hall effect measurements were employed to assess the structural, morphological, optical, and electrical properties of the samples. FTIR analysis confirmed the successful functionalization of graphite to GO and subsequent reduction to reduced graphene oxide, with peak intensities decreasing as the reduction temperature increased. UV-visible spectroscopy of GO showed a maximum absorption at 235 nm which confirmed the synthesis of GO while the reduction revealed a notable red shift in absorption peaks with increasing annealing temperature, and that signified a reduction in bandgap. XRD analyses demonstrated the removal of oxygen functional groups. The X-ray diffraction (XRD) analysis of GO showed diffraction at 2θ = 10.74° which revealed a fully oxidized graphene oxide with oxygen-containing functional groups, and hence an increase in interlayer spacing (d002) from 3.341 Å (graphite) to 8.228 Å (GO). Upon reduction, there is a gradual decrease in d002 from 8.228 Å (GO) to 3.387 Å (HRGO300), suggesting the gradual removal of intercalated oxygen molecules, and hence the gradual restoration of sp2 hybridisation in graphene. The EDS analysis revealed an increase in the carbon-to-oxygen (C/O) ratio from 1.78 in GO to 2.75 in HRGO300 as the annealing temperature for the reduction process increased which further confirmed the removal of oxygen functional groups. The Hall effect data showed hole mobility of 4.634 x101 (GO), 4.831 x101 (HRGO200), and 5.462 x100 (HRGO300) with conductivities of 8.985 x10-5 (GO), 1.087 x100 (HRGO200) and 1.791 x101 1/Ω cm, suggesting an increase in conductivity as the annealing temperature increased as revealed in the EDS. Out of the three samples identified as hole transport materials, the sample HRGO300 with the highest C/O ratio of 2.75 has the highest conductivity, and hence most suitable for application as hole transport material in perovskite solar cell.
{"title":"Facile synthesis and optimization of graphene oxide reduction by annealing in hydrazine vapour in ambient air for potential application in perovskite solar cells","authors":"S. Ochigbo, Alfred Obukohwo Obar, M.A.T. Suleiman, A.S. Kovo","doi":"10.4314/swj.v19i1.26","DOIUrl":"https://doi.org/10.4314/swj.v19i1.26","url":null,"abstract":"Graphene oxide (GO) was synthesized from graphite via a modified Hummer's method, followed by thermal and chemical reductions to produce reduced graphene oxide (RGO) samples at various temperatures. A suite of characterization techniques including Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDS), UV-Visible Spectroscopy, thermogravimetric analysis (TGA), X-ray diffraction (XRD), and Hall effect measurements were employed to assess the structural, morphological, optical, and electrical properties of the samples. FTIR analysis confirmed the successful functionalization of graphite to GO and subsequent reduction to reduced graphene oxide, with peak intensities decreasing as the reduction temperature increased. UV-visible spectroscopy of GO showed a maximum absorption at 235 nm which confirmed the synthesis of GO while the reduction revealed a notable red shift in absorption peaks with increasing annealing temperature, and that signified a reduction in bandgap. XRD analyses demonstrated the removal of oxygen functional groups. The X-ray diffraction (XRD) analysis of GO showed diffraction at 2θ = 10.74° which revealed a fully oxidized graphene oxide with oxygen-containing functional groups, and hence an increase in interlayer spacing (d002) from 3.341 Å (graphite) to 8.228 Å (GO). Upon reduction, there is a gradual decrease in d002 from 8.228 Å (GO) to 3.387 Å (HRGO300), suggesting the gradual removal of intercalated oxygen molecules, and hence the gradual restoration of sp2 hybridisation in graphene. The EDS analysis revealed an increase in the carbon-to-oxygen (C/O) ratio from 1.78 in GO to 2.75 in HRGO300 as the annealing temperature for the reduction process increased which further confirmed the removal of oxygen functional groups. The Hall effect data showed hole mobility of 4.634 x101 (GO), 4.831 x101 (HRGO200), and 5.462 x100 (HRGO300) with conductivities of 8.985 x10-5 (GO), 1.087 x100 (HRGO200) and 1.791 x101 1/Ω cm, suggesting an increase in conductivity as the annealing temperature increased as revealed in the EDS. Out of the three samples identified as hole transport materials, the sample HRGO300 with the highest C/O ratio of 2.75 has the highest conductivity, and hence most suitable for application as hole transport material in perovskite solar cell.","PeriodicalId":21583,"journal":{"name":"Science World Journal","volume":"23 21","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141019952","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yeasts are widely distributed in nature and can be isolated from nutrient rich substrates such as fruit and vegetable, fermented foods and beverages. Yeasts have been employed for millions of years in biotechnological applications in the production of bread, beer and wine. Saccharomyces cerevisiae is most important species when it comes to practical application in industries. Many developing countries including Nigeria spent billions of dollars annually on importation of active dry yeasts used in their baking and brewery industries. In order to reverse this trend, an attempt was made at improving the leavening capacity of S. cerevisiae isolated from locally made traditional alcoholic beverages by mutation induced by N-methyl-N-Nitro-N-Nitrosoguanidine (NTG). The yeast isolates were identified by their morphological properties and biochemical tests using standard methods. The viable counts of yeast isolated from the five alcoholic beverages employed in this study ranged between 1.4x107 and 2.4x108 CFU/mL. The yeast with the lowest percentage of occurrence (1.67%) are Geotricum candidum, Schizosaccharomyces japanicus, Sch. pombe, Candida intermedia etc. while S. cerevisiae had highest percentage of occurrence of 26.67%. S. cerevisiae PWII exhibited the highest dough rising ability among the parent strains, but S. cerevisiae M3 had the best dough rising power among the mutants. Physical examinations of the baked revealed that the bread samples produced with mutant strains compared favorably well with ones produced with commercial yeasts in terms of height, weight and volume. On the other hand bread samples produced using parent strains (PT 14 and PWII) had longer shelf life than bread from mutant and commercial strains. Sensory evaluation by taste panelists showed that the ranges of scores obtained are appearance (5.6-7.9), texture (6.3-8.1), taste (5.5-7.0), crumb (6.0-7.1) and overall acceptability (6.2-7.2). It could be concluded from this study that the leavening ability of S. cerevisiae could be enhanced by chemical mutagens and therefore could by employed in bread baking.
{"title":"Characterization and improvement of the leavening capacity of Saccharomyces cerevisiae isolated from Nigerian indigenous alcoholic beverages using a chemical mutagen","authors":"Aladeloye Kayode Adedayo, I. A. Adesokan","doi":"10.4314/swj.v19i1.28","DOIUrl":"https://doi.org/10.4314/swj.v19i1.28","url":null,"abstract":"Yeasts are widely distributed in nature and can be isolated from nutrient rich substrates such as fruit and vegetable, fermented foods and beverages. Yeasts have been employed for millions of years in biotechnological applications in the production of bread, beer and wine. Saccharomyces cerevisiae is most important species when it comes to practical application in industries. Many developing countries including Nigeria spent billions of dollars annually on importation of active dry yeasts used in their baking and brewery industries. In order to reverse this trend, an attempt was made at improving the leavening capacity of S. cerevisiae isolated from locally made traditional alcoholic beverages by mutation induced by N-methyl-N-Nitro-N-Nitrosoguanidine (NTG). The yeast isolates were identified by their morphological properties and biochemical tests using standard methods. The viable counts of yeast isolated from the five alcoholic beverages employed in this study ranged between 1.4x107 and 2.4x108 CFU/mL. The yeast with the lowest percentage of occurrence (1.67%) are Geotricum candidum, Schizosaccharomyces japanicus, Sch. pombe, Candida intermedia etc. while S. cerevisiae had highest percentage of occurrence of 26.67%. S. cerevisiae PWII exhibited the highest dough rising ability among the parent strains, but S. cerevisiae M3 had the best dough rising power among the mutants. Physical examinations of the baked revealed that the bread samples produced with mutant strains compared favorably well with ones produced with commercial yeasts in terms of height, weight and volume. On the other hand bread samples produced using parent strains (PT 14 and PWII) had longer shelf life than bread from mutant and commercial strains. Sensory evaluation by taste panelists showed that the ranges of scores obtained are appearance (5.6-7.9), texture (6.3-8.1), taste (5.5-7.0), crumb (6.0-7.1) and overall acceptability (6.2-7.2). It could be concluded from this study that the leavening ability of S. cerevisiae could be enhanced by chemical mutagens and therefore could by employed in bread baking.","PeriodicalId":21583,"journal":{"name":"Science World Journal","volume":"20 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141022135","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Thin film CdTe solar cells have been recognized as reliable alternative for the manufacture of cheap photovoltaic solar cells of the future, due to its excellent absorber characteristics and simple, low-cost manufacturability. However, for the attainment of higher cell performances, additional studies are needed to increase cell efficiency through further development of better quality films and new fabrication processes. In the substrate-structured CdTe thin film solar cells, the CdTe absorber layer is deposited directly onto the substrate or through a back contact layer. But the quality of deposited film is believed to depend on the type and smoothness of the substrate. In this work CdTe was deposited on different substrates by RF sputtering and the effects on the deposited films were studied in terms of their structural and morphological forms. The substrates used were: pure molybdenum sheets (Mo), molybdenum-sputtered on molybdenum (Mo/Mo), molybdenum-sputtered polyimide (PI/Mo) and molybdenum-sputtered glass (glass/Mo). The characterization tools used included XRD, SEM and AFM. The results showed that all surfaces produced uniform, compact and pinhole-free films; however, those on smoother surfaces produced larger as-deposited grain sizes of up to1.7μm as against 1.3 for rougher surfaces. Non-uniformities such as overgrowth and voids were observed, but only films on PI showed evidence of cracking and peel-offs.
碲化镉薄膜太阳能电池因其优异的吸收特性和简单、低成本的可制造性，已被公认为未来制造廉价光伏太阳能电池的可靠替代品。然而，为了实现更高的电池性能，还需要进行更多的研究，通过进一步开发质量更好的薄膜和新的制造工艺来提高电池效率。在基底结构碲化镉薄膜太阳能电池中，碲化镉吸收层直接沉积在基底上或通过背接触层沉积。但沉积薄膜的质量被认为取决于衬底的类型和光滑度。在这项研究中，碲化镉通过射频溅射沉积在不同的基底上，并研究了沉积薄膜的结构和形态对其产生的影响。使用的基底包括：纯钼片（Mo）、钼上溅射钼（Mo/Mo）、溅射钼聚酰亚胺（PI/Mo）和溅射钼玻璃（glass/Mo）。所用的表征工具包括 XRD、SEM 和 AFM。结果表明，所有表面都能产生均匀、致密和无针孔的薄膜；然而，在较光滑的表面上产生的沉积晶粒尺寸较大，可达 1.7 微米，而在较粗糙的表面上仅为 1.3 微米。观察到了不均匀现象，如过度生长和空洞，但只有 PI 表面的薄膜出现了开裂和剥离。
{"title":"Towards the fabrication of flexible thin film CdTe solar cells: The significance of substrate surfaces","authors":"M. Aliyu","doi":"10.4314/swj.v19i1.32","DOIUrl":"https://doi.org/10.4314/swj.v19i1.32","url":null,"abstract":"Thin film CdTe solar cells have been recognized as reliable alternative for the manufacture of cheap photovoltaic solar cells of the future, due to its excellent absorber characteristics and simple, low-cost manufacturability. However, for the attainment of higher cell performances, additional studies are needed to increase cell efficiency through further development of better quality films and new fabrication processes. In the substrate-structured CdTe thin film solar cells, the CdTe absorber layer is deposited directly onto the substrate or through a back contact layer. But the quality of deposited film is believed to depend on the type and smoothness of the substrate. In this work CdTe was deposited on different substrates by RF sputtering and the effects on the deposited films were studied in terms of their structural and morphological forms. The substrates used were: pure molybdenum sheets (Mo), molybdenum-sputtered on molybdenum (Mo/Mo), molybdenum-sputtered polyimide (PI/Mo) and molybdenum-sputtered glass (glass/Mo). The characterization tools used included XRD, SEM and AFM. The results showed that all surfaces produced uniform, compact and pinhole-free films; however, those on smoother surfaces produced larger as-deposited grain sizes of up to1.7μm as against 1.3 for rougher surfaces. Non-uniformities such as overgrowth and voids were observed, but only films on PI showed evidence of cracking and peel-offs.","PeriodicalId":21583,"journal":{"name":"Science World Journal","volume":"17 41","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141020223","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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