Adsorption kinetics of cadmium and lead by chitosan

An evaluation of the kinetics and capacity of chitosan to trap lead and cadmium ions in aqueous solution was carried out at 25oC using concentration and contact time as parameters. The experimentswere done as batch process. Our results show that the adsorption process is concentration-driven with high capacity of chitosan for the adsorption of these metal ions. The Infra red spectroscopic study on the chitosan and the metal-chitosan complexes reveal a metal coordination based on the observed characteristic band changes. At initial lead concentrations of 1000, 500, 400, 250 and 100 mg/L, the adsorbed lead ion concentrations are 557, 265, 218, 132 and 65 mg/L, respectively. However, for the cadmium, the adsorbed concentrations are 263, 165, 152, 78 and 45 mg/L, respectively at the same initial concentrations. The lead and cadmium adsorption kinetic behavior could not be described using the Langmuir isotherm over the whole concentration range but Freundlich isotherm conforms to the experimental data

Mandibular reconstruction: a new defect classification system

This paper presents a new mandibular segmental defect classification system (La-Co-CE) with a view to highlight the complexity and difficulty of the reconstruction with free autogenous bone grafts which the most frequently used method for surgeons practicing in developing countries. We submit that defect classification systems will continue to remain relevant if surgeons are to is pre-operatively classify the envisaged operative difficulty and objectively compare the outcome postoperatively. Key words: Mandibular reconstruction, defect, classification

The use of methemoglobin complex in estimating cyanogen potential of cassava and cassava products

An improved method of analysis of cyanide in cassava and cassava products using methemoglobin complex is described. The cyanogen content of cassava mash, pre-fufu mash, fufu and Gari wasdetermined spectrophotometrically. Optimal conditions were determined to be 24 h at 370C in phosphate buffer (0.05 M; pH 5.6). The average cyanogen content obtained were 14.68 ± 0.66, 13.49 ± 0.02, 11.94 ±0.02 and 9.87 ± 0.64 mg/kg for cassava mash, pre-fufu, fufu and gari, respectively. The values estimated for cassava mash and pre-fufu are greater than the values obtained for the processed fufu and gari, andalso greater than the WHO safe value for cassava flour (10 mg/kg). The fact that the results of this work gave lower values of cyanide in processed cassava products compared with the value of unprocessed cassava suggests the validity of this method

Clinical options for mandibular reconstruction: A review

This paper reviewed the different clinical options for reconstruction of segmental defects of the mandible. The options reviewed included no reconstruction; the use of prosthetic implants (alloplasts); autogenous bone grafts; combination of allopplasts with autografts; free pedicled compound grafts;combination of homografts and autografts; distraction osteogenesis; and tissue engineering. The goal, objectives, criteria for success of autogenous and alloplastic reconstructions were highlighted as well as the factors that may influence the choice of a particular method