1. Department of ChemistryFederal University of Maranhão 65080-805 São Luís, MA Brazil
2. Department of BiologyLaboratory of Genetics and Molecular BiologyFederal University of Maranhão-UFMA 65080-805 São Luís, MA Brazil
3. Department of Electrical EngineeringFederal University of Maranhão CEP 65080–805 São Luis, MA Brazil
4. Department of PhysicsFederal University of Maranhão CEP 65080–805 São Luis, MA Brazil