Computational Studies of Fullerene Derivatives as Pesticide Captors

The use of pesticides in tropical countries such as Brazil has grown resulting in alarming health damage statistics, deaths and environmental pollution. Considering its potential risk and the difficulty on detecting their residues instantaneously in field, six fullerene derivatives were planned using semiempirical calculations and molecular docking to understand its potential as adsorbents and captors of agricultural organophosphate (Ops) pesticides. As Ops were selected acephate, cadusafos, chlorpyrifos, dimethoate, fenitrothion, phenthoate, malaoxon, malathion, methyl-parathion and terbufos. The proposal 4 had the best results and between the Ops, fenitrothion presented the best results, followed by malathion, malaoxon, phentoate and methyl-parathion. DOI: http://dx.doi.org/10.17807/orbital.v11i1.121

News Aspects Theoric and Experimental to Paraffins Compounds

The paraffinic compounds are important to new investigation on the properties physics and its correlation with theoric dates, because in literature no is completely clarified. However, there are some studies on the formalism for developing asymptotic behavior correlation for homologous series paraffin compounds. In this work is show that the effect of parameters theoric obtained by molecular modeling can be correlated with experimental dates. To paraffins as pure, for example, n-hexane, C6H14, MW 158 g/mol, is composed of two groups CH3 and four groups CH2 and its can depending of structure molecular ramification to predict what your dependency with thermodynamics data. Therefore, the molecular modeling of paraffinic compounds uses a methodology that looks for data correlated with the structure of the molecule complemented with experimental data. The objective this study is correlated this molecular data with some thermodynamics data as enthalpy of formation and other parameters

Computational Studies of Fullerene Derivatives as Pesticide Captors

The use of pesticides in tropical countries such as Brazil has grown resulting in alarming health damage statistics, deaths and environmental pollution. Considering its potential risk and the difficulty on detecting their residues instantaneously in field, six fullerene derivatives were planned using semiempirical calculations and molecular docking to understand its potential as adsorbents and captors of agricultural organophosphate (Ops) pesticides. As Ops were selected acephate, cadusafos, chlorpyrifos, dimethoate, fenitrothion, phenthoate, malaoxon, malathion, methyl-parathion and terbufos. The proposal 4 had the best results and between the Ops, fenitrothion presented the best results, followed by malathion, malaoxon, phentoate and methyl-parathion. DOI: http://dx.doi.org/10.17807/orbital.v11i1.121

FPolymer: A Program for 3D Structure Generation and OPLS Topology of Polymers with High Molecular Mass

The need to study polymeric systems with high molecular masses by techniques such as molecular dynamics using free-use software, coupled with the difficulty of parameterizing such systems, led to the creation of the FPolymer program. This program was built in C++ language using the QT-creator framework and has a simple and intuitive interface. The main function of the program is to use previously parameterized trimers of any polymer to generate a structure with the number of repeating units indicated by the user. As output of the program, the user receives a file <file>.pdb containing the structure of the polymer and a file <file>.top with the topology prepared to perform youngest molecular dynamics in the GROMAS program. DOI: http://dx.doi.org/10.17807/orbital.v14i1.1698 &nbsp

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Human exposure to ultraviolet (UV) radiation leads photochemical excitation processes in the skin, causing problems to human health. The use of photoprotectors helps to minimize these intrinsic hazards. Benzophenone molecules stand out for the absorption of energy in the UVA and UVB range and structural changes in these, it is an area of ​​interest to obtain safer and more effective molecules. This work applied the full factorial design methodology 24 in an investigation by molecular modeling using semi-empirical method PM7, in order to evaluate the impact generated on the decrease of the energy GAP with the insertion of OH (level +) and H (level –-). The results showed unfavorable and favorable contributions between interactions and in the main effect, and the compounds disubstituted in ortho and para position for the same aromatic ring showed a better percentage of contribution, indicating that these conditions are relevant for greater reactivity compared to the others. Thus, we conclude that the use of the experimental planning methodology is an ally in obtaining information for planning new protective filtersmore stable and safe

FPolymer: A Program for 3D Structure Generation and OPLS Topology of Polymers with High Molecular Mass

The need to study polymeric systems with high molecular masses by techniques such as molecular dynamics using free-use software, coupled with the difficulty of parameterizing such systems, led to the creation of the FPolymer program. This program was built in C++ language using the QT-creator framework and has a simple and intuitive interface. The main function of the program is to use previously parameterized trimers of any polymer to generate a structure with the number of repeating units indicated by the user. As output of the program, the user receives a file .pdb containing the structure of the polymer and a file .top with the topology prepared to perform youngest molecular dynamics in the GROMAS program. DOI: http://dx.doi.org/10.17807/orbital.v14i1.1698

Comparative evaluation of five hydrological models in a large-scale and tropical river basin

Hydrological modeling is an important tool for water resources management, providing a feasible solution to represent the main hydrological processes and predict future streamflow regimes. The literature presents a set of hydrological models commonly used to represent the rainfallrunoff process in watersheds with different meteorological and geomorphological characteristics. The response of such models could differ significantly for a single precipitation event, given the uncertainties associated with the input data, parameters, and model structure. In this way, a correct hydrological representation of a watershed should include the evaluation of different hydrological models. This study explores the use and performance of five hydrological models to represent daily streamflow regimes at six hydropower plants located in the Tocantins river basin (Brazil). The adopted models include the GR4J, HYMOD, HBV, SMAP, and MGB-IPH. The evaluation of each model was elaborated considering the calibration (2014–2019) and validation period (2005–2010) using observed data of precipitation and climatological variables. Deterministic metrics and statistical tests were used to measure the performance of each model. For the calibration stage, results show that all models achieved a satisfactory performance with NSE values greater than 0.6. For the validation stage, only the MGB-IPH model present a good performance with NSE values greater than 0.7. A bias correction procedure were applied to correct the simulated data of conceptual models. However, the statistical tests exposed that only the MGB-IPH model could preserve the main statistical properties of the observed data. Thus, this study discusses and presents some limitations of the lumped model to represent daily streamflows in large-scale river basins (>50,000 km²)