Thermodynamic properties of 2,5-bis(4-dimethylaminophenyl)-1,3,4-oxadiazole as corrosion inhibitor of carbon steel in hydrochloric acid pickling environment

The corrosion inhibition of carbon steel in 1 M HCl by 2,5-bis(4-dimethylaminophenyl)-1,3,4-oxadiazole (DAPO) was investigated using weight loss method in the temperature range of 303–333 K. It was found that the inhibition efficiency increases with an increase in DAPO concentration but decreases with an increase in temperature. It has been determined that the adsorption for the studied inhibitor on carbon steel complies with the Langmuir adsorption isotherm at all studied temperatures. Both kinetic parameters (activation energy, pre-exponential factor, enthalpy of activation and entropy of activation) and thermodynamics of adsorption (enthalpy of adsorption, entropy of adsorption and Gibbs free energy) were calculated and discussed

Grain yield response of Fonio (Digitaria exilis) varieties to fertilizer and cost- effectiveness under two different production systems in the Gambia

Fonio is an easy crop to grow because it grows well even on poor sandy soils, as well as in areas with low rainfall. The crop can withstand long dry  spells during the production season which are becoming a common occurrence in the West African subregion. In The Gambia, the common name  for the crop is “Findi”. It is commonly grown in fields that were previously cultivated with groundnut. Fonio is one of the oldest cereal crops grown in  the country; however, its cultivation has drastically declined to the extent that it is currently considered a minor crop in the country. Fonio is a very  fast-growing crop and matures earlier than most cereals. Its ability to withstand dry spells and its high nutritive value makes it an ideal climate-  smart crop. For this reason, there is renewed momentum in promoting the crop in the country. Despite these renewed efforts in its promotion,  there still exists a huge gap in terms of information on improved production practices that could help uplift the existing low yields. Appropriate  agronomic practices that can boost fonio productivity are not well documented at national level. To gather information on the input requirements  and utilizations, adaptability and productivity of fonio in The Gambia, experiments were conducted in 2018 and 2019 with the aim of generating  important production information that could guide efficient production and enhance productivity. Results obtained showed that fonio responded  positively to application of fertilizer. Application of 100 kg ha -1 comprising half NPK (15-15-15) and half urea was sufficient to produce financially  beneficial yields. Results also indicated that “Findiba”, which is a landrace may not be suitable for cultivation anymore due to its long growth period  amidst the short and erratic nature of the rainfall. The Momo and the Momosato varieties which are of shorter durations and high-yielding are more  suitable in the existing climatic conditions of the country

Towards a biomedical engineering quality system: Writing documentation to support clinical & laboratory accreditation at MRC unit in the Gambia

5 Halama

Enhancement of corrosion protection efficiency of mild steel by 3,5-di(4-tolyl)-4-amino-1,2,4-triazole in hydrochloric acid medium

New 3,5-disubstituted-4-amino-1,2,4-triazole derivative, namely 3,5-di(4-tolyl)-4-amino-1,2,4-triazole (4-DTAT) was synthesised and its inhibitive action against the corrosion of mild steel in 1 M HCl solution was investigated at 308 K. The detailed study of 4-DTAT was been performed using gravimetric measurements and polarisation curves method. Results show that 4-DTAT is a good inhibitor and its inhibition efficiency reaches 95 % at·10−4 M. Tafel polarisation study revealed that 4-DTAT acts as a mixed type inhibitor. The adsorption of 4-DTAT on steel surface obeyed Langmuir’s adsorption isotherm. The inhibitor adsorption process in mild steel/4-DTAT/hydrochloric acid system was studied at different temperatures (308-323 K) by means of weight loss measurements

Diameter controlled growth of SWCNTs using Ru as catalyst precursors coupled with atomic hydrogen treatment

In this work, we present a practical approach for controlling single walled carbon nanotubes (SWCNTs) diameter distribution through thin film Ru catalyst, coupled with hydrogen pre-treatment. Uniform and stable Ru nanoclusters were obtained after dewetting the Ru thin films under atomic hydrogen pre-treatment. SWCNTs were synthetized by double hot filament chemical vapor deposition (d-HFCVD) on SiO2/Si substrates at different temperatures. We found that the temperature is an important synthesis parameter that in fluences the diameter distribution of the final SWCNTs. Statistical analysis of the Raman radial breathing modes evidences the growth of highly enriched semi-conducting SWCNTs (about 90%) with narrow diameter distribution that correlates directly with the catalyst particle size distribution. Electrical measurement results on as-grown SWCNTs show good thin-film transistor characteristics

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

Maternal and neonatal outcomes after caesarean delivery in the African Surgical Outcomes Study: a 7-day prospective observational cohort study.

BACKGROUND: Maternal and neonatal mortality is high in Africa, but few large, prospective studies have been done to investigate the risk factors associated with these poor maternal and neonatal outcomes. METHODS: A 7-day, international, prospective, observational cohort study was done in patients having caesarean delivery in 183 hospitals across 22 countries in Africa. The inclusion criteria were all consecutive patients (aged ≥18 years) admitted to participating centres having elective and non-elective caesarean delivery during the 7-day study cohort period. To ensure a representative sample, each hospital had to provide data for 90% of the eligible patients during the recruitment week. The primary outcome was in-hospital maternal mortality and complications, which were assessed by local investigators. The study was registered on the South African National Health Research Database, number KZ_2015RP7_22, and on ClinicalTrials.gov, number NCT03044899. FINDINGS: Between February, 2016, and May, 2016, 3792 patients were recruited from hospitals across Africa. 3685 were included in the postoperative complications analysis (107 missing data) and 3684 were included in the maternal mortality analysis (108 missing data). These hospitals had a combined number of specialist surgeons, obstetricians, and anaesthetists totalling 0·7 per 100 000 population (IQR 0·2-2·0). Maternal mortality was 20 (0·5%) of 3684 patients (95% CI 0·3-0·8). Complications occurred in 633 (17·4%) of 3636 mothers (16·2-18·6), which were predominantly severe intraoperative and postoperative bleeding (136 [3·8%] of 3612 mothers). Maternal mortality was independently associated with a preoperative presentation of placenta praevia, placental abruption, ruptured uterus, antepartum haemorrhage (odds ratio 4·47 [95% CI 1·46-13·65]), and perioperative severe obstetric haemorrhage (5·87 [1·99-17·34]) or anaesthesia complications (11·47 (1·20-109·20]). Neonatal mortality was 153 (4·4%) of 3506 infants (95% CI 3·7-5·0). INTERPRETATION: Maternal mortality after caesarean delivery in Africa is 50 times higher than that of high-income countries and is driven by peripartum haemorrhage and anaesthesia complications. Neonatal mortality is double the global average. Early identification and appropriate management of mothers at risk of peripartum haemorrhage might improve maternal and neonatal outcomes in Africa. FUNDING: Medical Research Council of South Africa.Medical Research Council of South Africa