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Search Results: 1 - 10 of 463877 matches for " Williams J. C. Macêdo "
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Evaluation of Quantum Chemical Methods and Basis Sets Applied in the Molecular Modeling of Artemisinin  [PDF]
Cleydson B. R. dos Santos, Cleison C. Lobato, Josinete B. Vieira, Davi S. B. Brasil, Alaan U. Brito, Williams J. C. Macêdo, José Carlos T. Carvalho, José C. Pinheiro
Computational Molecular Bioscience (CMB) , 2013, DOI: 10.4236/cmb.2013.33009
Abstract: In this paper, we evaluate semiempirical methods (AM1, PM3, and ZINDO), HF and DFT (B3LYP) in different basis sets to determine which method best describes the sign and magnitude of the geometrical parameters of artemisinin in the region of the endoperoxide ring compared to crystallographic data. We also classify these methods using statistical analysis. The results of PCA were based on three main components, explaining 98.0539% of the total variance, for the geometrical parameters C3O13, O1O2C3, O13C12C12a, and O2C3O13C12. The DFT method (B3LYP) corresponded well with the experimental data in the hierarchical cluster analysis (HCA). The experimental and theoretical angles were analyzed by simple linear regression, and statistical parameters (correlation coefficients, significance, and predictability) were evaluated to determine the accuracy of the calculations. The statistical analysis exhibited a good correlation and high predictive power for the DFT (B3LYP) method in the 6-31G** basis set.
Application of Hartree-Fock Method for Modeling of Bioactive Molecules Using SAR and QSPR  [PDF]
Cleydson B. R. Santos, Cleison C. Lobato, Francinaldo S. Braga, Sílvia S. S. Morais, Cesar F. Santos, Caio P. Fernandes, Davi S. B. Brasil, Lorane I. S. Hage-Melim, Williams J. C. Macêdo, José C. T. Carvalho
Computational Molecular Bioscience (CMB) , 2014, DOI: 10.4236/cmb.2014.41001
Abstract:
The central importance of quantum chemistry is to obtain solutions of the Schr?dinger equation for the accurate determination of the properties of atomic and molecular systems that occurred from the calculation of wave functions accurate for many diatomic and polyatomic molecules, using Self Consistent Field method (SCF). The application of quantum chemical methods in the study and planning of bioactive compounds has become a common practice nowadays. From the point of view of planning it is important to note, when it comes to the use of molecular modeling, a collective term that refers to methods and theoretical modeling and computational techniques to mimic the behavior of molecules, not intend to reach a bioactive molecule simply through the use of computer programs. The choice of method for energy minimization depends on factors related to the size of the molecule, parameters of availability, stored data and computational resources. Molecular models generated by the computer are the result of mathematical equations that estimate the positions and properties of the electrons and nuclei, the calculations exploit experimentally, the characteristics of a structure, providing a new perspective on the molecule. In this work we show that studies of Highest Occupied Molecular Orbital Energy (HOMO), Low Unoccupied Molecular Orbital Energy (LUMO) and Map of molecular electrostatic potential (MEP) using Hatree-Fock method with different basis sets (HF/3-21G*, HF/3-21G**, HF/6-31G, HF/6-31G*, HF/6-31G** and HF/6-311G), that are of great importance in modern chemistry, biochemistry, molecular biology, and other fields of knowledge of health sciences. In order to obtain a significant correlation, it is essential that the descriptors are used appropriately. Thus, the quantum chemical calculations are an attractive source of new molecular descriptors that can, in principle, express all the geometrical and electronic properties of molecules and their interactions with biological receptor.
A SAR and QSAR Study of New Artemisinin Compounds with Antimalarial Activity
Cleydson Breno R. Santos,Josinete B. Vieira,Cleison C. Lobato,Lorane I. S. Hage-Melim,Raimundo N. P. Souto,Clarissa S. Lima,Elizabeth V. M. Costa,Davi S. B. Brasil,Williams Jorge C. Macêdo,José Carlos T. Carvalho
Molecules , 2014, DOI: 10.3390/molecules19010367
Abstract: The Hartree-Fock method and the 6-31G** basis set were employed to calculate the molecular properties of artemisinin and 20 derivatives with antimalarial activity. Maps of molecular electrostatic potential (MEPs) and molecular docking were used to investigate the interaction between ligands and the receptor (heme). Principal component analysis and hierarchical cluster analysis were employed to select the most important descriptors related to activity. The correlation between biological activity and molecular properties was obtained using the partial least squares and principal component regression methods. The regression PLS and PCR models built in this study were also used to predict the antimalarial activity of 30 new artemisinin compounds with unknown activity. The models obtained showed not only statistical significance but also predictive ability. The significant molecular descriptors related to the compounds with antimalarial activity were the hydration energy (HE), the charge on the O11 oxygen atom (QO11), the torsion angle O1-O2-Fe-N2 (D2) and the maximum rate of R/Sanderson Electronegativity (RTe +). These variables led to a physical and structural explanation of the molecular properties that should be selected for when designing new ligands to be used as antimalarial agents.
INTEGRAL TRANSFORM METHOD FOR LAMINAR HEAT TRANSFER CONVECTION OF HERSCHEL-BULKLEY FLUIDS WITHIN CONCENTRIC ANNULAR DUCTS
Viana, M.J.G.;Nascimento, U.C.S.;Quaresma, J.N.N.;Macêdo, E.N.;
Brazilian Journal of Chemical Engineering , 2001, DOI: 10.1590/S0104-66322001000400001
Abstract: related momentum and energy equations describing the heat and fluid flow of herschel-bulkley fluids within concentric annular ducts are analytically solved using the classical integral transform technique, which permits accurate determination of parameters of practical interest in engineering such as friction factors and nusselt numbers for the duct length. in analyzing the problem, thermally developing flow is assumed and the duct walls are subjected to boundary conditions of first kind. results are computed for the velocity and temperature fields as well as for the parameters cited above with different power-law indices, yield numbers and aspect ratios. comparisons are also made with previous work available in the literature, providing direct validation of the results and showing that they are consistent.
INTEGRAL TRANSFORM METHOD FOR LAMINAR HEAT TRANSFER CONVECTION OF HERSCHEL-BULKLEY FLUIDS WITHIN CONCENTRIC ANNULAR DUCTS
Viana M.J.G.,Nascimento U.C.S.,Quaresma J.N.N.,Macêdo E.N.
Brazilian Journal of Chemical Engineering , 2001,
Abstract: Related momentum and energy equations describing the heat and fluid flow of Herschel-Bulkley fluids within concentric annular ducts are analytically solved using the classical integral transform technique, which permits accurate determination of parameters of practical interest in engineering such as friction factors and Nusselt numbers for the duct length. In analyzing the problem, thermally developing flow is assumed and the duct walls are subjected to boundary conditions of first kind. Results are computed for the velocity and temperature fields as well as for the parameters cited above with different power-law indices, yield numbers and aspect ratios. Comparisons are also made with previous work available in the literature, providing direct validation of the results and showing that they are consistent.
Differential Midgut Attachment of Leishmania (Viannia) braziliensis in the Sand Flies Lutzomyia (Nyssomyia) whitmani and Lutzomyia (Nyssomyia) intermedia
Rodrigo P. Soares,Carina Margonari,Nágila C. Secundino,Maria E. Macêdo,Simone M. da Costa,Elizabeth F. Rangel,Paulo F. Pimenta,Salvatore J. Turco
Journal of Biomedicine and Biotechnology , 2010, DOI: 10.1155/2010/439174
Abstract: The interaction between Leishmania and sand flies has been demonstrated in many Old and New World species. Besides the morphological differentiation from procyclic to infective metacyclic promastigotes, the parasite undergoes biochemical transformations in its major surface lipophosphoglycan (LPG). An upregulation of -glucose residues was previously shown in the LPG repeat units from procyclic to metacyclic phase in Leishmania (Viannia) braziliensis, which has not been reported in any Leishmania species. LPG has been implicated as an adhesion molecule that mediates the interaction with the midgut epithelium of the sand fly in the Subgenus Leishmania. These adaptations were explored for the first time in a species from the Subgenus Viannia, L. (V.) braziliensis with its natural vectors Lutzomyia (Nyssomyia) intermedia and Lutzomyia (Nyssomyia) whitmani. Using two in vitro binding techniques, phosphoglycans (PGs) derived from procyclic and metacyclic parasites were able to bind to the insect midgut and inhibit L. braziliensis attachment. Interestingly, L. braziliensis procyclic parasite attachment was ~11-fold greater in the midgut of L. whitmani than in L. intermedia. The epidemiological relevance of L. whitmani as a vector of American Cutaneous Leishmaniasis (ACL) in Brazil is discussed.
Características agron?micas e químicas das variedades de cana-de-a?úcar RB83-5486 e RB86-7515 sob irriga??o e sequeiro
Macêdo, Geraldo A. R.;Costa, édio L. da;Viana, Maria C. M.;Ferreira, José J.;Pires, Jamile F.;Freire, Francisco M.;
Revista Brasileira de Engenharia Agrícola e Ambiental , 2012, DOI: 10.1590/S1415-43662012000600002
Abstract: the study aimed to evaluate the agronomic characteristics and chemical composition of sugarcane varieties, harvested at the end of the dry season, under irrigated and rainfed conditions. the experimental design was in a completely randomized blocks with six replications. two varieties (rb83-5486 and rb86-7515) under irrigated and rainfed conditions were studied. the stalk and dry matter yield were improved by irrigation, especially in case of rb86-7515. higher contents of crude protein, acid detergent fiber, cellulose and lower contents of dry matter, brix, non-fiber carbohydrates (nfc) and in vitro dry matter digestibility (ivdmd) were obtained in the varieties under irrigation. the neutral detergent fiber (ndf) and ndf/brix were higher in irrigated conditions, variety rb86-7515 showing higher values. the lignin content was higher in the rb86-7515 under irrigated conditions. the rb83-5486 presented a better content of brix, nfc and ivdmd than the rb86-7515. high productive potential was expressed under irrigated conditions, with emphasis on the rb86-7515. irrigation influenced the chemical composition, negatively affecting the nutritional value of varieties. the rb83-5486 showed a better nutritional profile to be used as forage.
Níveis críticos e tóxicos de boro em solos de Pernambuco determinados em casa de vegeta??o
Lima, Júlio César Patrício de Souza;Nascimento, Clístenes Williams Araújo do;Lima, Júlio Guilherme da Costa;Lira Junior, Mário de Andrade;
Revista Brasileira de Ciência do Solo , 2007, DOI: 10.1590/S0100-06832007000100008
Abstract: research on b availability in soils is essential to assess the crops response to different concentrations of available b in soils. a greenhouse experiment was carried out aiming at studying the corn plant (zea mays) response to b doses (0, 2, 4, 6, and 12 mg dm-3) applied to ten soils from the state of pernambuco, brazil. available b was assessed by three extractants: hot water, hcl 0.05 mol l-1, and mehlich-1. the critical and toxic levels were determined in soils and plants. additionally, b toxicity symptoms in corn plants were recorded. results showed that the critical and toxic b levels in soils ranged from 0.4 to 2.3 mg kg-1 and from 1.8 to 8.3 mg kg-1, respectively. for corn plants, the critical levels varied from 13.8 to 129.6 mg kg-1 and the toxic levels from 43.3 to 372.2 mg kg-1. hcl 0.05 mol l-1 was the extractant that best correlated with the b plant content, followed by mehlich-1 and hot water. both available b assessed by hcl and b plant contents were inversely related to clay and organic matter concentrations in soils. soils on which plants with highest b contents grew presented the most acute b toxicity symptoms. this was associated with sandy and low organic matter soils.
Defeitos congênitos em bovinos da Regi?o Central do Rio Grande do Sul
Macêdo, J.T.S.A.;Lucena, R.B.;Giaretta, P.R.;Kommers, G.D.;Fighera, R.A.;Irigoyen, L.F.;Barros, C.S.L.;
Pesquisa Veterinária Brasileira , 2011, DOI: 10.1590/S0100-736X2011000400005
Abstract: cases of congenital defects (cds) in cattle diagnosed at the laboratory of veterinary pathology of the federal university of santa maria from 1964 to 2010 were reviewed. during the studied period tissues collected from the necropsy of 7,132 cattle were examined and 31 calves (0.4%) with cds were found. these cds were classified into 34 different types and ascribed to the body system primarily affected. cds were solitary (19 [61.3%]) or multiple (12 [38.7%]) and found with similar frequency in calves of both sexes. as several calves displayed multiple defects, a total of 53 cds were computed. out of the 53types of cds diagnosed 15 (28.3%) affected the central nervous system (cranioschisis [4], cerebellar abiotrophy [2], spongy degeneration [2], hydrocephalus [2], meningocele [2], spina bifida [1], cerebellar hypoplasia [1], and hypomyelinogenesis [1]); nine (17.0%) affected the urogenital system (testicular agenesis [1], vaginal agenesia [1], penile hypoplasia [1], cloacal formation [1], freemartinism [1], ovarian vascular hamartoma [1], renal hypoplasia [1], renal cysts [1], and persistent urachus [1]); eight cds (15,1%) were primary to the musculoskeletal system (arthrogryposis [4], scoliosis [1], plagiocephaly [1] schistosomus reflexus [1], and diprosopus [1]) and another eight (15,1%) were in the digestive system (palatoschisis [3], anal atresia [1], anorectal atresia [1], ano-colonic atresia [1], recto-vaginal fistula [1], and recto-urethral fistula [1]); in five instances (9.4%) the cd affected the cardiovascular system (persistent ductus arteriosus [2], persistence of foramen ovale [2], and ventricular septal defect [1]); four (7.5%) affected the lymphatic system and consisted of inherited hypoplasia or aplasia of lymphatic vessels and lymph nodes associated with lymphedema. two cases (3.0%), of hypotrichosis were observed affecting the integument; one case (1.9%) of tracheal stenosis was found in the respiratory system and one case of goiter (1.9%) involved t
Enfermagem e a promo??o da saúde mental na família: uma reflex?o teóric
Macêdo, Virgílio César Dourado de;Monteiro, Ana Ruth Macêdo;
Texto & Contexto - Enfermagem , 2004, DOI: 10.1590/S0104-07072004000400011
Abstract: the family is considered indispensable for the guarantee of the survival and protection of its members, providing the affection and material support necessary for development and well-being, being in its interior absolved ethical values deepened bows, and solidarity. the family needs to be qualified to supply those needs, being indispensable the maintenance of its mental health. the article provokes reflection on family relationships, vital cycles and values in the family and on the family's nursing, searching to promote the discussion about possibilities to offer support in mental health in the families, furthering an improvement in the quality of interaction among its members.
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