Petro Chemistry of Major and Trace Elements Concentrations in the Stream Sediments of Awo Area and its Environs, Southwestern Nigeria.

Stream sediments are believed to record the environmental impact on fluvial system overtime and are often study to determine the overall pollution of an environment. This research work is aimed at mineralogical appraisal of various rock types through petro logical study, also to estimate the degree of enrichment of the element in the stream sediments and to determine if such enrichment has led to any form of pollution and also to produce a baseline geochemical data base for further geochemical investigation of the area under investigation. Ten soil samples were collected randomly within the study area and were analyzed for major and trace elements concentration using the Inductively Coupled Plasma Mass Spectrometry (ICP-MS) instrumentation techniques, while five rock types were selected for petro graphic studies. Thin section study shows that muscovite, biotite, microcline, and quartz are the main mineral assemblages present in the rocks of the study area. The result of the geochemical analysis were thereafter subjected to multivariate statistical analysis, the statistical plot from the result of major elements shows that Iron oxide (Fe2O3)  range from 9.30% - 1.60 %, with a mean value of 4.6865%. Aluminum oxide (Al2O3) range from 2.63% - 0.55% with a mean value of 1.6802%, Fe2O3 and Al2O3 are dominant major oxides within the study area and they show moderate enrichment in the environment under investigation.  From the result of the trace elements, Manganese [ Mn] with mean value of 3996.00 ppm, Zinc [Zn] with mean value of 272.40 ppm,  Copper [Cu]  with mean value of 628.10 ppm, Lead [Pb] with a mean value of 61.22 ppm, Nickel [Ni] with a mean value of 109.40 ppm and Cobalt [Co] with  mean value of  89.0 ppm have high concentration within the area of study, with Copper [Cu] having the highest degree of contamination factor 33%. The enrichment of Lead [ Pb] in the study area has been linked to anthropogenic  input of exhaust from motor bikes that ply the area, very strong positive correlation exist between V and Cr  (0.737), Co and Ni (0.648) while a positive strong correlation exist between Co and Cr (0.550), Mo and Ga  (0.535) indicating that they are from the same source. The conclusion drawn from the box plot study show that V, Cr, Co, Ni, Zn, Mn, As,  Rb,  Pb, Mo, Ga and Cd have values that are greater than zero, while Sr and  Zr have values that are less than zero. Copper [Cu] is the highest contaminating element within the study area, the presence of high amount of cupper in the study area may be probably due to geogenic factor, and in addition the  weathering of the associated rocks and precipitation of same within the environment and it can also be attributed to the mining operations going on in the study area; from this it can therefore  be deduced  that the study area range in the category of practically contaminated to moderately contaminated. Keywords: Sediment, Biotite, Enrichment, weathering, Geogeni

Tropical climate, ecology and hydrology during the Paleocene-Eocene Thermal Maximum

The Paleocene-Eocene Thermal Maximum (PETM) plays a key role in the paleoclimate research, as it represents an imperfect analogue to future warming. The PETM was a geologically brief (~170 kyr) episode of extreme global warming. A pronounced negative carbon isotope excursion (CIE) in sedimentary components and deep sea carbonate dissolution reflect massive and rapid carbon input at that time. Documentation of this period is extensive for the high and mid latitudes, but the tropics remain virtually untouched. However, for the full understanding of PETM climates the tropical end member needs to be quantified in terms of temperature and hydrology. We have studied an Upper Paleocene – Lower Eocene shelf section from Nigeria deposited at equatorial latitudes. Carbon isotope analysis and palynological analysis in the form of dinoflagellate cyst assemblages have been conducted and biomarker analysis has been started. Carbon isotope analysis on total organic carbon (TOC) revealed an excursion of ~ -6‰. Dinoflagellate cyst biostratigraphy confirms that this CIE represents the PETM. Shifts in species composition in the preliminary dinocyst assemblage data set are interpreted in terms of temperature, salinity, sea level, eutrophication and stratification. Representatives of the dinocyst genus Apectodinium are present throughout the section and abundant before the CIE. However, during the CIE this genus is surprisingly absent, while it dominates all other PETM assemblages studied so far. Its absence may be due to extreme fresh water input or extreme tropical temperatures. Finally, we will present preliminary organic biomarker analysis, including TEX86 paleothermometr

Novel laccase from Xylaria polymorpha and its efficiency in the biotransformation of pharmaceuticals:Optimization of operational conditions, comparative effect of redox-mediators and toxicity studies

The promising potentials of biocatalytic treatment processes in the removal of micropollutants whilst eliminating health and environmental hazards have attracted great attention in recent years. This current work investigated the biotransformation efficiency of a novel laccase from Xylaria polymorpha (XPL) in comparison with commercial laccases from Trametes versicolor (TVL) and Aspergillus sp. (ASL). XPL exhibited better oxidation performance (95.7%) on AMX than TVL (92.8%) and ASL (90.5%). Optimization of operational conditions revealed that AMX was best oxidized at pH 5, temperature (30 °C), and concentration (1.0 mg L −1). The investigation carried out to determine the effect of redox mediators revealed violuric acid (VLA) as the best redox mediator. The laccase stability experiments elucidated that the oxidation of AMX is time and mediator concentration dependent with ABTS exhibiting highest deactivation of XPL active sites. Two metabolic products; amoxicillin penilloic acid and 5-hydroxy-6-(4-hydroxyphenyl)− 3-(1,3-thiazolidin-2-yl)piperazin-2-one of AMX were obtained through Liquid Chromatography-Mass Spectrometry (LC-MS) analyses. The toxicity assessments carried out after oxidation of AMX by XPL showed 94% and 97% reduced toxicity on Artemia salina and Aliivibrio fischeri respectively. The study further underscored the efficiency of biocatalytic-mediator technology in the transformation of complex micropollutants into less toxic substances in an eco-friendly way

The ASOS Surgical Risk Calculator: development and validation of a tool for identifying African surgical patients at risk of severe postoperative complications

Background: The African Surgical Outcomes Study (ASOS) showed that surgical patients in Africa have a mortality twice the global average. Existing risk assessment tools are not valid for use in this population because the pattern of risk for poor outcomes differs from high-income countries. The objective of this study was to derive and validate a simple, preoperative risk stratification tool to identify African surgical patients at risk for in-hospital postoperative mortality and severe complications. Methods: ASOS was a 7-day prospective cohort study of adult patients undergoing surgery in Africa. The ASOS Surgical Risk Calculator was constructed with a multivariable logistic regression model for the outcome of in-hospital mortality and severe postoperative complications. The following preoperative risk factors were entered into the model; age, sex, smoking status, ASA physical status, preoperative chronic comorbid conditions, indication for surgery, urgency, severity, and type of surgery. Results: The model was derived from 8799 patients from 168 African hospitals. The composite outcome of severe postoperative complications and death occurred in 423/8799 (4.8%) patients. The ASOS Surgical Risk Calculator includes the following risk factors: age, ASA physical status, indication for surgery, urgency, severity, and type of surgery. The model showed good discrimination with an area under the receiver operating characteristic curve of 0.805 and good calibration with c-statistic corrected for optimism of 0.784. Conclusions: This simple preoperative risk calculator could be used to identify high-risk surgical patients in African hospitals and facilitate increased postoperative surveillance. © 2018 British Journal of Anaesthesia. Published by Elsevier Ltd. All rights reserved.Medical Research Council of South Africa gran