Physicochemical Characterization of Limestone Deposits at Ewekoro, Ogun State, South-West of Nigeria and the Environment Impact

Limestone is the primary constituent raw material for cement manufacture. While most limestone deposits are suitable for cement making, there are some characteristics of limestone which need to be defined in order to establish a usable raw material supply.  These relate to compositional requirements and also the consistency of the deposit in chemical and physical terms. Limestone makes up about 10% of the total volume of all sedimentary rocks. The solubility of limestone in water and weak acid solutions leads to karst landscapes, in which water erodes the limestone over thousands to millions of years. The density and porosity of samples from the various locations vary from 2.61g/cm3 to 2.72g/cm3 and 2.70% to 3.80%. The Schmidt hammer rebound number of samples from Ewekoro quarry varies from 32.1 to 33.6. The uniaxial compressive strength of samples from Ewekoro quarry varies from 60.5 MPa to 63.5 MPa thereby classifying the rock as moderate to high strength. The point load strength index is obtained from the LAFARGE laboratory results and varies from 1.239 MPa to 2.185 MPa. The strength classifications fall within the range of moderate to high strength class. Also, the tensile strength, obtained from point load strength ranges from 1.862 MPa to 3.086 MPa. The staining process induces a reaction on the surface of a particular mineral species which results in coloured precipitate characteristic of that mineral. Alizarin red S in NaOH stained the samples purple indicating the presence of magnesium in the carbonate while Alizarin red S in HCL stained the samples red. Physical observation of Ewekoro limestone deposit reveal the rock is highly fossiliferous with the identified fossils indicating deposition in an open shelf environment. Moreover, the limestone deposit was equally observed to be principally mud supported which is indicative of rocks deposited in quiet water and a low energy environment. Keywords: Limestone, Solubility, Ewekoro, Physical and Chemical

Advances in Perovskite-Based Solar Cells

The increase in energy demand due to increase in population and reduction of fossil fuels has led to the search of alternative energy sources. Solar energy, which is an alternative source of energy, has been in the fore front of this research. Various methods of converting solar energy into electricity has been attained by silicon solar cells, thin film solar cells, dye sensitized solar cells and perovskite solar cells. Unlike dye sensitized solar cells, perovskite solar cells based on lead halide perovskite or organic-inorganic halide perovskite have had a significant impact on photovoltaic devices. A power conversion efficiency of approximately 20.1% has been attained by perovskite solar cells compared to organic solar cells. Also, several fabrication techniques, hole and electron transport materials have been developed for high performance. Although, some issues need to be addressed before commercialization is possible. Issues like stability of the cells under moisture and temperature. In this review, fundamental aspects of the perovskite device and recent breakthroughs are illustrate

A Geochemical Analytical Scheme for the Appraisal of Partitioning and Mobility of Major elements in Weathered Dry Disposed Coal Fly Ash

South Africa is endowed with significant deposits of coal which is utilized in electricity generation to meet the nation’s energy demand. A large volume of waste solid residue from the combustion of pulverized feed coal in power stations is dry disposed in stock piles or dumps. Chemical interactions of dry disposed fly ash with ingressed CO2 from the atmosphere and infiltrating rain water would cause dissolution of the soluble components in the fly ash matrix. Chemical partitioning and mobility of major elements in samples from cores drilled into serially stacked weathered dry disposed fly ash were investigated using a modified five steps sequential extraction scheme. A total acid digestion was carried out on the original ash core samples prior to extraction to validate the extraction procedure. The geochemical distribution of the investigated major elements in 59 drilled core samples was determined by x-ray fluorescence and inductively coupled plasma mass spectrometry. The relationship between SiO2 and chemical index of alteration (CIA) showed 8 year and 20-year-old core samples have a moderate to high degree of weathering. Conversely, 1-year-old cores samples showed characteristics between low and moderate-high degrees of weathering. A cluster and discriminant analysis of the major elements was also able to reveal the subtle chemical alteration differences of the core samples. Functional analysis revealed the disparities in the dissolution patterns of major soluble components in the matrix of the drilled core samples. Modified sequential extractions revealed high concentration of the major species in the leachates for every mineralogical fraction; although the bulk of the major elements are locked up in the insoluble phase of the core samples (i.e. residual fraction) which would not be released under normal environmental conditions. It is noteworthy that the concentration of major elements in the labile fractions (water soluble + exchangeable + carbonate) was high and this has implications for the long-term durability of residual mineral phases. Relative enrichment and depletion trends of major elements are promoted by heterogeneity in the ash dump (i.e. moisture content), gradual reduction of pore water pH and continuous brine and water irrigation.Key words: Coal fly ash; Weathering; Sequential extraction scheme; Cluster analysis; Factor Analysis

EU Nature Restoration Law; EGU Response

The EGU Biodiversity Task Force welcomes the ambitious targets outlined in the Nature Restoration Law that was presented by the European Commission on 22 June 2022. To ensure the Nature Restoration Law is successful, the EGU Biodiversity Task Force is recommending seven key points to be added, amended, or strengthened throughout the document

Cost of Corrosion of Metallic Products in Federal University of Agriculture, Abeokuta

The cost of corrosion has been increasing drastically due to the degradation of the metallic materials. This study was carried out to estimate the “Cost of Corrosion of Metallic Products in Federal University of Agriculture, Abeokuta (FUNAAB)”. Questionnaires were administered and interviews were also conducted to gather necessary information. The cost of corrosion from 2013-2015 was estimated and analysed with the aid of engineering economy method and statistical analysis method. For the cost of corrosion prevention methods, cleaning gave the highest cost contribution (69%), followed by the use of oil (30%), use of grease (1%), and painting gave zero percent of the total cost. While on the cost of corrosion maintenance methods, repair gave the highest cost contributions (66%), and prevention gave (34%) of the total cost. The overall cost of corrosion from (2013-2015) gave an upward trend, but a downward trend in future value and the annualized value. While the forecast cost from (2013-2016) at (95%) confidence level and (5%) significance level gave an upward trend. The present value, future value, and annualized value from (2013-2016) increased by (66%, 43%, and 75%) respectively. The total cost and the total annualized value of corrosion from (2013-2015) were estimated to be N 166,955,641 and N 93,791,024, and with the forecast (2013-2016) were found to be N 277,650,388 and N 163,672,460 respectively. Under the corrosion prevention methods and corrosion maintenance methods, cleaning and repair gave highest cost contribution respectively. Corrosion prevention methods need to be added to bring down the repair cost of those facilities for saving cost

Progress on Organic Solar Cells: A Short Review

Thin film organic solar cells have emerged as a replacement to inorganic solar cells based on silicon. Organic solar cells offer several advantages compared to silicon-based devices. In the last 10 years, concentrated research attempts towards accomplishing the mandatory power conversion efficiency of 10 % and environmental stability of the device still remain a main challenge. In order to influence the efficiency, polymers are frequently utilized to fabricate the absorber and buffer layers. Also, binary and tenary polymer blends have been devised to influence the performance in micro/nanostructures. In addition, the advantages of organic solar cells for realistic application, and potential solutions are also considered

Neuronal Alterations and Antioxidant Status of Lipopolysaccharide Induced Neuronal damage in Mice: Eff icacy of Three Medicinal Plants

Background: Several factors including neuroinflammation and oxidative stress formation contribute to the progression and development of cognitive impairment. Lipopolysaccharide (LPS) injection has been used as non - transgenic mouse models for Alzheimer’s diseases (AD). Plant medicine has been proposed to be the prospect in treatment/ management of neurodegenerative disease. Aim: The present study sought to evaluate the effect of three medicinal plants ( Bacopa floribunda (R.Br)Wettst , Scoparia dulcis L and Cordia millenii Bak . ) locally used for memory enhancement on neuronal histology and antioxidant status against L ipopolysaccharide induced neuronal damage in mice . Methods: Forty - nine (49) BALB/c male mice were randomly grouped into seven (7) groups of 7 mice each. All animals except in group I control (vehicle), were injected intraperitoneally (I.P.) with LPS (250 μg/kg) once, after oral pre - treatment with plant extracts an d control drugs for 7 days. Group II (untreated) received LPS only (250 μg/kg) , group III received LPS + Sulindac Sulfide (SS, 4 mg/kg), group IV received LPS + Donepezil (DPZ, 1 mg/kg) group V, VI, and VII received LPS + 200 mg/kg of plant extracts [ Sco paria dulcis (SD), Bacopa floribunda (BF), and Cordia millenii (CM)] respectively. After the experiment, histological analysis of the hippocampus from the whole brain was carried out while the other brain tissue s comprising frontal cortex and cerebellum we re used for determination of biomarkers of antioxidant status such as catalase (CAT); superoxide dismutase (SOD); malondialdehyde (MDA) and reduced glutathione (GSH). Results: Oral administration of LPS induced neuronal damage through cell death as eviden ced by the histological analysis and altered brain antioxidant status in mice. However, the plant extracts were able to prevent such neuronal alterations and restored the antioxidant status when compared to the LPS induced neuronal damage in mice. Conclusi on: LPS induced neuroinflammation was prevented by the extracts of; B. floribunda, S. dulcis and C. millenni. Neural damage was also prevented by the extracts. This activity could be attributed to their antioxidant potential as evidenced from their inhibit ory effect on MDA and increased CAT activity and GSH. Nevertheless, other possible mechanisms of action against neuronal damage need to be assessed to further justify their use traditionally in the treatment/management of neurodegenerative disease

Biological sample donation and informed consent for neurobiobanking: Evidence from a community survey in Ghana and Nigeria

Copyright: \ua9 2022 Singh et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Introduction Genomic research and neurobiobanking are expanding globally. Empirical evidence on the level of awareness and willingness to donate/share biological samples towards the expansion of neurobiobanking in sub-Saharan Africa is lacking. Aims To ascertain the awareness, perspectives and predictors regarding biological sample donation, sharing and informed consent preferences among community members in Ghana and Nigeria. Methods A questionnaire cross-sectional survey was conducted among randomly selected community members from seven communities in Ghana and Nigeria. Results Of the 1015 respondents with mean age 39.3 years (SD 19.5), about a third had heard of blood donation (37.2%, M: 42.4%, F: 32.0%, p = 0.001) and a quarter were aware of blood sample storage for research (24.5%; M: 29.7%, F: 19.4%, p = 0.151). Two out of ten were willing to donate brain after death (18.8%, M: 22.6%, F: 15.0%, p<0.001). Main reasons for unwillingness to donate brain were; to go back to God complete (46.6%) and lack of knowledge related to brain donation (32.7%). Only a third of the participants were aware of informed consent (31.7%; M: 35.9%, F: 27.5%, p<0.001). Predictors of positive attitude towards biobanking and informed consent were being married, tertiary level education, student status, and belonging to select ethnic groups. Conclusion There is a greater need for research attention in the area of brain banking and informed consent. Improved context-sensitive public education on neurobiobanking and informed consent, in line with the sociocultural diversities, is recommended within the African sub region

Geochemical fractionation of hazardous elements in fresh and drilled weathered South African coal fly ashes

The chemical reactions of dry-disposed ash dump, ingressed oxygen, carbon dioxide, and infiltrating rainwater affect mineralogical transformation, redistribution, and migration of chemical species. Composite samples of weathered coal fly ash taken at various depths and fresh coal fly ash were examined using organic petrographic, X-ray diffraction, X-ray fluorescence techniques, and successive extraction procedures. Results obtained show relative enrichment of glass, Al–Fe-oxides, calcite, and tridymite in the weathered CFA, but the fresh CFA is enriched in mullite, inertinite, maghemite, and ettringite. The enrichment of the weathered CFA in amorphous glass suggests higher reactivity when compared to fresh CFA. The evident depletion of soluble oxides in the weathered CFA is attributed to flushing of the soluble salts by percolating rainwater. Comparative enrichment of examined elements in water-soluble, exchangeable, reducible, and residual fractions of the weathered CFA is partly due to the slow release of adsorbed chemical species from the alumina-silicate matrix and diffusion from the deeper sections of the particles of coal fly ash. Sodium and potassium show enrichment in the oxidisable fraction of fresh CFA. The estimated mobility factor indicates mobility for Ca, Mg, Na, Se, Mo, and Sb and K, Sr, V, Cu, Cr, Se, and B in fresh and weathered CFAs, respectively

Blood pressure–associated polymorphism controls ARHGAP42 expression via serum response factor DNA binding

We recently demonstrated that selective expression of the Rho GTPase-activating protein ARHGAP42 in smooth muscle cells (SMCs) controls blood pressure by inhibiting RhoA-dependent contractility, providing a mechanism for the blood pressure–associated locus within the ARHGAP42 gene. The goals of the current study were to identify polymorphisms that affect ARHGAP42 expression and to better assess ARHGAP42’s role in the development of hypertension. Using DNase I hypersensitivity methods and ENCODE data, we have identified a regulatory element encompassing the ARHGAP42 SNP rs604723 that exhibits strong SMC-selective, allele-specific activity. Importantly, CRISPR/Cas9–mediated deletion of this element in cultured human SMCs markedly reduced endogenous ARHGAP42 expression. DNA binding and transcription assays demonstrated that the minor T allele variation at rs604723 increased the activity of this fragment by promoting serum response transcription factor binding to a cryptic cis-element. ARHGAP42 expression was increased by cell stretch and sphingosine 1-phosphate in a RhoA-dependent manner, and deletion of ARHGAP42 enhanced the progression of hypertension in mice treated with DOCA-salt. Our analysis of a well-characterized cohort of untreated borderline hypertensive patients suggested that ARHGAP42 genotype has important implications in regard to hypertension risk. Taken together, our data add insight into the genetic mechanisms that control blood pressure and provide a potential target for individualized antihypertensive therapies