| 1. |
- Andrea, Anders, et al.
(författare)
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A theoretical hypothesis of beverage cooling by reverse heating inconsumer microwave ovens by using fullerenol (polyhydroxylatedfullerenes) dissolved in acetone
- 2018
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Ingår i: International Journal of Applied Physics. - 2367-9034. ; 3
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Tidskriftsartikel (refereegranskat)abstract
- Cooling of beverages is of large interest. Here a theoretical idea of how microwave ovens can be usedfor cooling beverages is presented. The proposed theoretical idea based on heat transfer features a microwavesafe (isoprene rubber) torus shaped rubber ring (MWSR) holding a liquid (L) at room temperature. Fullerenoldissolved in acetone (L) inside MWSR (L) will absorb energy directly from the microwave radiation and therebyincrease its temperature. The liquid to be cooled (B) will also absorb energy from the microwave radiation, butthe net effect is the cooling of B as the heat transfer is faster in L than in B due to L’s lower boiling point andheat of vaporization. The cooling fan of the microwave oven facilitates the heat transfer mechanism. Thebeverage B is theoretically cooled from room temperature (20 °C) to around 4 °C in around 58 seconds. Basedon heat absorption of fullerenol—which could be transformed from liquid phase to vapour phase—a beverageliquid (300 g water) in a glass put inside the microwave oven could be cooled (reversely heated) by the heatgenerated by the microwave oven. The user of the proposed method would be able cool 300 ml of beverage toless than 4 °C in just a minute using consumer microwave ovens.
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| 2. |
- Behzadi, Hadi, et al.
(författare)
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Application of calculated NMR parameters, aromaticity indices and wavefunction properties for evaluation of corrosion inhibition efficiency of pyrazine inhibitors
- 2018
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Ingår i: Journal of Molecular Structure. - : Elsevier. - 0166-1280 .- 0022-2860. ; 1151, s. 34-40
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Tidskriftsartikel (refereegranskat)abstract
- In light of the importance of developing novel corrosion inhibitors, a series of quantum chemical calculations were carried out to evaluate 15N chemical shielding CS tensors as well as aromaticity indexes including NICS, HOMA, FLU, and PDI of three pyrazine derivatives, 2-methylpyrazine (MP), 2-aminopyrazine (AP) and 2-amino-5-bromopyrazine (ABP). The NICS parameters have been shown in previous studies to be paramount to the prediction of anti-corrosion properties, and have been combined here with HOMA, FLU and PDI and detailed wavefunction analysis to determine the effects from bromination and methylation on pyrazine. The results show that the electron density around the nitrogens, represented by CS tensors, can be good indicators of anti-corrosion efficiency. Additionally, the NICS, FLU and PDI, as aromaticity indicators of molecule, are well correlated with experimental corrosion inhibition efficiencies of the studied inhibitors. Bader sampling and detailed wavefunction analysis shows that the major effects from bromination on the pyrazine derivatives affect the Laplacian of the electron density of the ring, delocalizing the aromatic electrons of the carbon atoms into lone pairs and increasing polarization of the Laplacian values. This feature is well agreement with empirical studies, which show that ABP is the most efficient anti-corrosion compound followed by AP and MP, a property which can be attributed and predicted by derivation of the Laplacian of the electron density of the ring nuclei. This study shows the importance of devising DFT methods for development of new corrosion inhibitors, and the strength of electronic and nuclear analysis, and depicts most importantly how corrosion inhibitors composed of aromatic moieties may be modified to increase anti-corrosive properties.
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| 3. |
- Behzadi, Hadi, et al.
(författare)
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Relationship between electronic properties and drug activity of seven quinoxaline compounds : A DFT study
- 2015
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Ingår i: Journal of Molecular Structure. - : Elsevier BV. - 0022-2860 .- 1872-8014. ; 1091, s. 196-202
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Tidskriftsartikel (refereegranskat)abstract
- The quantum chemical calculations at the DFT/B3LYP level of theory were carried out on seven quinoxaline compounds, which have been synthesized as anti-Mycobacterium tuberculosis agents. Three conformers were optimized for each compound and the lowest energy structure was found and used in further calculations. The electronic properties including E-HOMO, E-LUMO and related parameters as well as electron density around oxygen and nitrogen atoms were calculated for each compound. The relationship between the calculated electronic parameters and biological activity of the studied compounds were investigated. Six similar quinoxaline derivatives with possible more drug activity were suggested based on the calculated electronic descriptors. A mechanism was proposed and discussed based on the calculated electronic parameters and bond dissociation energies.
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| 4. |
- Ghisi, Rossella, et al.
(författare)
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Accumulation of perfluorinated alkyl substances (PFAS) in agricultural plants : A review
- 2019
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Ingår i: Environmental Research. - : Elsevier BV. - 0013-9351 .- 1096-0953. ; 169, s. 326-341
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Forskningsöversikt (refereegranskat)abstract
- PFASs are a class of compounds that include perfluoroalkyl and polyfluoroalkyl substances, some of the most persistent pollutants still allowed - or only partially restricted - in several product fabrications and industrial applications worldwide. PFASs have been shown to interact with blood proteins and are suspected of causing a number of pathological responses, including cancer. Given this threat to living organisms, we carried out a broad review of possible sources of PFASs and their potential accumulation in agricultural plants, from where they can transfer to humans through the food chain. Analysis of the literature indicates a direct correlation between PFAS concentrations in soil and bioaccumulation in plants. Furthermore, plant uptake largely changes with chain length, functional group, plant species and organ. Low accumulations of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) have been found in peeled potatoes and cereal seeds, while short-chain compounds can accumulate at high levels in leafy vegetables and fruits. Significant variations in PFAS buildup in plants according to soil amendment are also found, suggesting a particular interaction with soil organic matter. Here, we identify a series of challenges that PFASs pose to the development of a safe agriculture for future generations.
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| 5. |
- Kamerlin, Natasha, et al.
(författare)
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Toward a Computational Ecotoxicity Assay
- 2020
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Ingår i: Journal of Chemical Information and Modeling. - : American Chemical Society (ACS). - 1549-9596 .- 1549-960X. ; 60:8, s. 3792-3803
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Tidskriftsartikel (refereegranskat)abstract
- Thousands of anthropogenic chemicals are released into the environment each year, posing potential hazards to human and environmental health. Toxic chemicals may cause a variety of adverse health effects, triggering immediate symptoms or delayed effects over longer periods of time. It is thus crucial to develop methods that can rapidly screen and predict the toxicity of chemicals to limit the potential harmful impacts of chemical pollutants. Computational methods are being increasingly used in toxicity predictions. Here, the method of molecular docking is assessed for screening potential toxicity of a variety of xenobiotic compounds, including pesticides, pharmaceuticals, pollutants, and toxins derived from the chemical industry. The method predicts the binding energy of pollutants to a set of carefully selected receptors under the assumption that toxicity in many cases is related to interference with biochemical pathways. The strength of the applied method lies in its rapid generation of interaction maps between potential toxins and the targeted enzymes, which could quickly yield molecular-level information and insight into potential perturbation pathways, aiding in the prioritization of chemicals for further tests. Two scoring functions are compared: Autodock Vina and the machine-learning scoring function RF-Score-VS. The results are promising, although hampered by the accuracy of the scoring functions. The strengths and weaknesses of the docking protocol are discussed, as well as future directions for improving the accuracy for the purpose of toxicity predictions.
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| 6. |
- Lu, Tian, et al.
(författare)
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Wavefunction and reactivity study of benzo[a]pyrene diol epoxide and its enantiomeric forms
- 2014
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Ingår i: Structural Chemistry. - : Springer Science and Business Media LLC. - 1040-0400 .- 1572-9001. ; 25:5, s. 1521-1533
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Tidskriftsartikel (refereegranskat)abstract
- Benzo[a]pyrene is a known carcinogen, which derives from fossil fuel combustion, cigarette smoke, and generic biomass combustion including traffic emissions. This potent carcinogen has a well-known mechanism of action, leading to the formation of adducts with the DNA, primarily at guanosine positions. The reactivity and chemistry of this notorious compound are, however, dependent on the electronic configuration of the biologically activated metabolite, the benzo[a]pyrene diol epoxide. The activated metabolite exists mainly as four isomers, which have particular chemical reactivities toward guanosine sites on the DNA. These isomers exert also a different carcinogenicity compared to one another, which is a feature that is conventionally attributed to their geometry. However, the reactivity and properties of the isomers are not fully defined, and a determination of these properties by wavefunction behavior is required. This study reports the electronic properties of the benzo[a]pyrene diol epoxide enantiomers, along with a detailed analysis of the energy landscape, geometry, and electronic configuration of the epoxide ring. The results show that the epoxide ring, the core of the reactivity, bears different properties at the level of wavefunction for each isomer. Each of the isomers has a distinct profile on the epoxide ring, in terms of hydrogen bonds and in terms of the non-covalent interaction between the diol groups and the epoxide. These profiles generate differential reactivities of epoxide group, which can be attributed to its local bond lengths, the electron localization function, and polarized bonds. Most interestingly, the quantum chemical calculations showed also that the epoxide ring is inclined more perpendicularly toward the angular ring plane for the more carcinogenic isomers, a feature which suggests a potential geometrical relationship between the inclination of the epoxide group and its interaction with the guanosine group upon adduct formation. Our results introduce novel and crucial information, which assist in understanding the mechanism of toxic potential of this known molecule, and display the strength and level of detail of applying quantum chemical methods to reveal the reactivity, energy properties, and electronic properties of a mutagen.
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| 7. |
- Manzetti, Sergio, et al.
(författare)
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A Korteweg-DeVries type model for helical soliton solutions for quantum and continuum phenomena
- 2021
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Ingår i: International Journal of Modern Physics C. - : World Scientific. - 0129-1831. ; 32:03
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Tidskriftsartikel (refereegranskat)abstract
- Quantum mechanical states are normally described by the Schrödinger equation, which generates real eigenvalues and quantizable solutions which form a basis for the estimation of quantum mechanical observables, such as momentum and kinetic energy. Studying transition in the realm of quantum physics and continuum physics is however more difficult and requires different models. We present here a new equation which bears similarities to the Korteweg–DeVries (KdV) equation and we generate a description of transitions in physics. We describe here the two- and three-dimensional form of the KdV like model dependent on the Plank constant ℏ and generate soliton solutions. The results suggest that transitions are represented by soliton solutions which arrange in a spiral-fashion. By helicity, we propose a conserved pattern of transition at all levels of physics, from quantum physics to macroscopic continuum physics.
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| 8. |
- Manzetti, Sergio, et al.
(författare)
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A molecular dynamics study of nanoparticle-formation from bioethanol-gasoline blend emissions
- 2016
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Ingår i: Fuel. - : Elsevier BV. - 0016-2361 .- 1873-7153. ; 183, s. 55-63
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Tidskriftsartikel (refereegranskat)abstract
- Aerosol components and nanoparticles deriving from fuel combustion represent a class of exhaust emissions with critical relevance to environmental studies. In particular, the formation of nanoparticles is an important theme for environmental assessments of new fuel blends. Here, a set of computer simulations is carried out to study the behaviour of acetaldehyde-phenanthrene nanoparticles in relation to the influences to the three major atmospheric components CO2, O-2, N-2. The results show that phenanthrene and acetaldehyde quickly generate nanoparticles with dimensions of 2-5 nm in vacuum. The formed particles are stable in atmospheric conditions and interestingly absorb CO2 from the atmosphere-gas simulations but not O-2 and N-2. The probability of absorption of CO2 in the formed nanoparticles results as 10-20-fold compared to N-2 and O-2. Furthermore, acetaldehyde appears to localize on the surface of the formed nanoparticles, and seemingly acts with the planar geometry of phenanthrene as a facilitator for CO2 absorption. The results provided show also the properties of formed nanoparticle with higher concentrations of acetaldehyde and lower of phenanthrene, where phenanthrene forms the core of the nanoparticle, while acetaldehyde interacts with the surface and subsurface area in making their chemistry hydrophilic with a dense aromatic core. The study is important for further assessing bioethanol and fuel blends, and also introduces a methodology for studying interactions of gases and particles at the molecular level, with macroscopic significance. The study reports on growth of nanoparticles by CO2 absorption, introduces a new issue for blending fuels, with implications towards pollution profiles.
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| 9. |
- Manzetti, Sergio, 1975-, et al.
(författare)
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Addendum: Solvation Energies of Butylparaben, Benzo[a]pyrene diol epoxide, Perfluorooctanesulfonic acid, and DEHP in Complex with DNA Bases
- 2018
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Ingår i: Chemical Research in Toxicology. - : American Chemical Society (ACS). - 0893-228X .- 1520-5010. ; 31:8, s. 639-640
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The bonding mechanisms between DEHP, PFOS, butylparaben and benzo[a]pyrene with the DNA were recently published [1] and showed intriguing mechanisms of complex formation between these priority pollutants and the gene core fragment of the p53 suppressor which were analyzed at the electronic level. The study supplied also important bonding data, including solvent model by molecular dynamics simulation and quantum chemical energies of electronic interaction between the pollutants and the DNA. It was however not included in this study the effect of the solvent on the electronic landscape of the molecules, which is the ultimate description of whether an interaction is truly favored by the ubiquitous solvent phase of water which participates in all cellular and biomolecular mechanisms and reactions and governs the structures of all biomolecules [2]. It is for this reason that we wish to submit this addendum which finally defines the true energies of interaction of the published complexes [1] which includes the SMD solvation model [3]. The calculations show that all complexes form under favorable energies when the SMD quantum chemical solvent model is included, and hence the necessary confirmation of the favorable effects of solvent on the potential energy landscape is confirmed for these geometries. Table 1 shows the bonding energies of the published complexes [1], which are here derived using the procedure using Gaussian16 A.03 package [4], where the geometries of complexes were optimized at B3LYP-D3(BJ)/6-311G* [5] level under SMD solvation model and a single point energy was derived to generate the energies.
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| 10. |
- Manzetti, Sergio, et al.
(författare)
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Alternant conjugated oligomers with tunable and narrow HOMO-LUMO gaps as sustainable nanowires
- 2013
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Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 3:48, s. 25881-25890
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Tidskriftsartikel (refereegranskat)abstract
- Novel nanowire technologies encompass the use of metals and crystals with a high electric transport potential and superior charge-collection properties. However, nanowires built on metals such as cadmium, gallium-arsenide and similar alloys present serious environmental and health risks. The use of carbon is a far more environmentally friendly solution than heavy-metal based nanowires, and if arranged in a particular manner, it can provide excellent conductive properties that are applicable in nanowire technologies. Herein, we report an investigation into the particular carbon-based 4n/4n + 2 alternant resonance, which has the potential of becoming a key component for the design of novel and conductive nanomaterials, suitable for application in optoelectronics, nanoelectronics and microelectronics. A set of nine 4n/4n + 2 oligomers comprising in the range of 15-20 cyclic units (similar to 5 nm) were analyzed quantum mechanically. The results show that the number and type (4n or 4n + 2) of carbon-rings (cyclobutadiene, benzene and naphthalene) that constitute the oligomers, govern the HOMO-LUMO gaps with a statistical relevance of R-2 = 0.919. Interestingly, we found that the sequence of the units played a central role in shaping the conductance of the 4n/4n + 2 oligomers, and that the sequencing of units in conductive carbon-based oligomers can be a potential future approach in tailoring the gaps of carbon-based conductive components for application in molecular electronics devices. An interesting relationship was also found between the symmetry and the homo-and heteromorphism of the LUMO elements with the HOMO-LUMO gaps, suggesting a pattern of continuity and wavefunction-symmetry across the LUMO orbitals of the 4n/4n + 2 systems to be a key-element determining the narrow gaps in the conductive carbon oligomers. In addition, population and electrostatic potential analysis showed that pi-electron distribution over the oligomers is quite non-uniform. The electron delocalization behavior over the 4n and 4n + 2 rings was characterized by electron localization function, six-center bond order, and a striking linear relationship was found between the pi-delocalization index of the C-C bonds and the HOMO-LUMO gaps (R-2 = 0.988). The results presented herein introduce valuable approaches and data for the engineering of conductive materials to be applied in the field of nanoelectronics and microelectronics, and to relieve the development of nanowires from its dependence on expensive and rare metals.
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