Biosorptive removal of cobalt (II) ions from aqueous solution by Amaranthus hydridus L. stalk wastes

The objective of this study was to investigate the possibility of using Amaranthus hybridus L. stalk as an alternative to high cost commercial adsorbent materials for the removal of Co (II) from aqueous solution. The experiment was carried out by batch method at 33°C. The influence of pH, contact time and initial metal ion concentration were evaluated. It was observed that pH had marked effect on the Co (II) uptake. The optimum contact time between the adsorbent and the adsorbate was found to be 90 min. Maximum adsorption was obtained at pH 5. Freundlich models were used to correlate equilibrium data on sorption of Co (II) ion at 33°C and pH 5, and different coefficients were calculated. The data generated, fitted well with Freundlich adsorption model. The biomass was successfully used for removal of cobalt (II) ion from synthetic aqueous solution and the technique appears industrially applicable and viable.Key words: Biosorption, cobalt, aqueous solution, Amaranthus hydrides

Comparative Analysis of Direct Labour and Contracting System of Project Procurement

This study examines the performance of two project procurement methods commonly used in project construction, the direct labour and contracting system. Using cost, time and quality as assessment criteria, the work seek to determine possible advantage of one method over the other. Quasi-experimental design and questionnaire were combined to carry this study. Respondents was mainly officers and building contractors, key players in project procurement. Results obtained in this work showed that there was no significant difference between the two methods in terms of cost overrun, though overall cost was higher for the direct labour method. It also revealed a significant difference between time overrun for the two methods as direct method took longer time. The study concluded by emphasising the need for training, openness and empowerment. It also recommended the need for all establishments to adopt participatory project management through direct labour. Key Words: Direct Labour, Contract, Procurement, Time, Cost, Cost overrun, Time overrun DOI: 10.7176/CER/11-8-07 Publication date:September 30th 201

Cellulase and Pectinase Production Potentials of Aspergillus Niger Isolated from Corn Cob

Production of pectinase and cellulase by Aspergillus niger from corn cob was examined. The organism was screened for enzymatic activity using Carboxyl Methyl Cellulose (CMC) and Pectin as substrate. The result revealed a clear zone of inhibition in the agar plates. The organism was subjected to different optimum conditions which include pH, temperature, biomass yield and enzymatic activity. The highest cellulose activity was obtained on the 4th day (1.9×10-4μg/ml/sec) while the highest pectinase activity (1.5×10-4μg/ml/sec) was obtained on the 4th and 5th day. The optimum pH for cellulase production was pH 4 with an activity of 2.70×10-4μg/ml/sec while the optimum pH for pectinase activity was pH 6 with an activity of 1.5×10-4 μg/ml/sec. The optimum temperature was at 50oC with an enzyme activity of 1.3x10-4μg/ml/sec for cellulase production while the optimum temperature of 60oC gave the highest pectinase activity of 1.6x10-4 μg/ml/sec. This study revealed that Aspergillus niger from corn cob has the ability to produce cellulase and pectinase, hence it may be considered as a source for the production of industrial cellulase and pectinase

Sustainable conversion of agro-wastes into useful adsorbents

Preparation and characterization of raw andactivated carbon derived from three different selectedagricultural wastes: kola nut pod raw and activated (KNPRand KNPA), bean husk raw and activated (BHR and BHA)and coconut husk raw and activated (CHR and CHA) wereinvestigated, respectively. Influences of carbonization andacid activation on the activated carbon were investigatedusing SEM, FTIR, EDX, pHpzcand Boehm titration tech-niques, respectively. Carbonization was done at 350°C for2 h followed by activation with 0.3 M H3PO4(ortho-phosphoric acid). Results obtained from SEM, FTIR, andEDX revealed that, carbonization followed by acid acti-vation had a significant influence on morphology and ele-mental composition of the samples. SEM showed well-developed pores on the surface of the precursors after acidtreatment, FTIR spectra revealed reduction, broadening,disappearance or appearance of new peaks after acid acti-vation. EDX results showed highest percentage of carbonby atom respectively in the order BHA[KNPA[CHArespectively. The pHpzcwas found to be 5.32, 4.57 and 3.69for KNPA, BHA and CHA, respectively. Boehm titrationresult compliments that of pHpzc, indicating that the sur-faces of the prepared adsorbents are predominantly acidic.This study promotes a sustainable innovative use of agro-wastes in the production of cheap and readily availableactivated carbons, thereby ensuring more affordable waterand effluent treatment adsorbents

Global overview of the management of acute cholecystitis during the COVID-19 pandemic (CHOLECOVID study)

Background: This study provides a global overview of the management of patients with acute cholecystitis during the initial phase of the COVID-19 pandemic. Methods: CHOLECOVID is an international, multicentre, observational comparative study of patients admitted to hospital with acute cholecystitis during the COVID-19 pandemic. Data on management were collected for a 2-month study interval coincident with the WHO declaration of the SARS-CoV-2 pandemic and compared with an equivalent pre-pandemic time interval. Mediation analysis examined the influence of SARS-COV-2 infection on 30-day mortality. Results: This study collected data on 9783 patients with acute cholecystitis admitted to 247 hospitals across the world. The pandemic was associated with reduced availability of surgical workforce and operating facilities globally, a significant shift to worse severity of disease, and increased use of conservative management. There was a reduction (both absolute and proportionate) in the number of patients undergoing cholecystectomy from 3095 patients (56.2 per cent) pre-pandemic to 1998 patients (46.2 per cent) during the pandemic but there was no difference in 30-day all-cause mortality after cholecystectomy comparing the pre-pandemic interval with the pandemic (13 patients (0.4 per cent) pre-pandemic to 13 patients (0.6 per cent) pandemic; P = 0.355). In mediation analysis, an admission with acute cholecystitis during the pandemic was associated with a non-significant increased risk of death (OR 1.29, 95 per cent c.i. 0.93 to 1.79, P = 0.121). Conclusion: CHOLECOVID provides a unique overview of the treatment of patients with cholecystitis across the globe during the first months of the SARS-CoV-2 pandemic. The study highlights the need for system resilience in retention of elective surgical activity. Cholecystectomy was associated with a low risk of mortality and deferral of treatment results in an increase in avoidable morbidity that represents the non-COVID cost of this pandemic

Antibacterial activity of Ficus capensis

The leaves and stem bark of Ficus capensis were investigated for antibacterial activity against some selected organisms at a concentration of 2000 ìg/ml using agar diffusion method. The crude leaf extract inhibited the growth of Escherichia  coli and Shigella sp. but no activity against Salmonella typhi. The stem bark extracts also had activity against E. coli and Shigella sp. but no activity against S. typhi. The phytochemical screening of the extracts reveals the presence of alkaloids, balsams, taninins, carbohydrates, resins, flavonoids, Sterols and terpenes. Glycosides were absent in the leaf extract while the stem bark extract had glycosides. Both extracts did not posses free arthraquinones and saponins. The Minimum inhibitory concentration (MIC) of the extracts range from 500-2000 ìg/ml. The fractions obtained from the thin layer chromatography had no activity on the test organisms. The results from the activity of the crude extracts suggest that F. capensis could be used in treatment of diseases caused by these bacteria except S. typhi