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BACKGROUND: Changes in sensory afferent interfere with the control of postural stability by the central nervous system. Wearing high-heeled shoes is an example of an external disturbance that changes sensory inputs and results in several postural adjustments to control stability. Thus, our purpose is to investigate the influence of high-heeled shoes and visual absence on maintenance of static balance and on ankle muscle activity among young women. Our hypothesis is that the combination of high-heeled shoes with visual absence lead to an increase of postural sway and of levels of activation of the stabilizing ankle muscles. METHODS: Nine volunteers remained in an unrestrained erect posture on a force platform for collecting of stabilometric and electromyographic parameters in four bipodal conditions: barefoot with open eyes, barefoot with closed eyes, with high heels and open eyes and with high heels and closed eyes. RESULTS: When comparing the experimental condition open and closed eyes with high heels, there were significant differences for all stabilometric variables, except for the confidence ellipse area. Statistical differences were found for the medial gastrocnemius muscle in all comparison pairs with high heels. CONCLUSION: The wearing high-heeled shoes showed to be the most influencing disturbance on static balance. Our findings suggest ankle muscle activity is adapted according to changes of the center of pressure sway and the wearing of high heels changes the muscle activation and postural sway.
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Electromiografía , Músculo Esquelético , Equilibrio Postural , Zapatos , Humanos , Equilibrio Postural/fisiología , Femenino , Músculo Esquelético/fisiología , Adulto , Adulto Joven , Articulación del Tobillo/fisiologíaRESUMEN
INTRODUCTION: The anterior cruciate ligament (ACL) is the most frequently injured ligament of the knee. However, quantitative studies on evaluate the postural control influence resulted from the ACL remnant preservation or not are scarce. The aim of this study is to evaluate the postural control of patients submitted to ACL reconstruction with and without preservation of the injured remnant in pre and postoperative periods. METHODS: Eighteen patients underwent ACL reconstruction and separated into 2 groups according to the preservation or not of the remnant: (I) submitted to ACL reconstruction with preservation of the remnant (10 patients); (II) submitted to ACL reconstruction without preservation of the remnant (8 patients). They were assessed using the Lysholm score and force plate, which evaluated the patient's postural stability for remnant and non-remnant preservation in ACL reconstruction surgery. RESULTS: Group I showed statistically significant subjective and objective improvements, both at 3 and 6 months. Additionally, improvement of the Lysholm test at 6 months in Group II was also statistically significant. Furthermore, the results of the Friedman test for the VCOP and VY variables of Group I, with support of the injured side in the force plate, showed a statistically significant difference both for pre and postoperative period at 3 months, compared to the 6-month postoperative period. The variables EAC and VX were statistically different for Group II, considering the preoperative period, 3 and 6 months postoperatively. CONCLUSION: Preserving the ACL remnant in patients with ACL injuries has a positive impact on postural stability during recovery.
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Lesiones del Ligamento Cruzado Anterior , Reconstrucción del Ligamento Cruzado Anterior , Humanos , Ligamento Cruzado Anterior/cirugía , Articulación de la Rodilla/cirugía , Lesiones del Ligamento Cruzado Anterior/cirugía , Reconstrucción del Ligamento Cruzado Anterior/métodos , Extremidad Inferior/cirugíaRESUMEN
The competitive demand for attention is present in our daily lives, and the identification of neural processes in the EEG signals associated with the demand for specific attention can be useful to the individual's interactions in virtual environments. Since EEG-based devices can be portable, non-invasive, and present high temporal resolution technology for recording neural signal, the interpretations of virtual systems user's attention, fatigue and cognitive load based on parameters extracted from the EEG signal are relevant for several purposes, such as games, rehabilitation, and therapies. However, despite the large amount of studies on this subject, different methodological forms are highlighted and suggested in this work, relating virtual environments, demand of attention, workload and fatigue applications. In our summarization, we discuss controversies, current research gaps and future directions together with the background and final sections.
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In this work, we report a theoretical study of the structural, electronic, and optical properties of palmitic acid crystal in its C form under DFT calculations level. Palmitic acid is a fatty acid that constitutes the large majority of vegetable oils with recognized potential applications in medicine, pharmaceuticals, cosmetics technology, foods, and fuel. As a main result, we have found that the electronic bandstructure reveals an indirect gap given by 3.713 eV (EâB andEâΓ), as a main bandgap, while the secondary bandgaps found were 4.175 eV (γ1âΓ) and 4.172 eV (γ2âB). It behaves like a wide bandgap semiconductor, which points to potential applications in optoelectronic devices.
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Nowadays, boron nitride has attracted a great deal of attention due to its physical (chemical) properties, facile synthesis, and experimental characterization, indicating great potential for industrial application. Based on this, we develop here a theoretical study on boron nitride nanoflakes built-up from hexagonal boron nitride nanosheets exhibiting hexagonal, rectangular, and triangular shapes. In order to investigate geometry effects such as those due to the presence of armchair and zigzag edges and distinct shapes, we analyzed their properties from both classical and quantum viewpoints. Using classical molecular dynamics calculations, we show that the nanosheets preserve their structural stability at high temperatures, while DFT calculations demonstrate HOMO-LUMO energy gap variation within the theoretical energy gaps of h-BN in bulk and 2D crystals. Besides that, we have also found that boron nitride nanoflakes structures have spatially symmetrical spin densities.
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Rose Bengal@α-cyclodextrin (RB@α-CD) microparticles (µPs) were prepared and the RB inclusion in α-CD was experimentally demonstrated through infrared, UV-VIS absorption spectroscopy and cyclic voltammetry. The RB inclusion in α-CD was theoretically investigated using classical molecular mechanics calculations, the simulation results showing that RB can be included in both the narrow and wide apertures of the α-cyclodextrin ring with configurations exhibiting average binding energies of about 27 kcal mol-1. The prepared RB@α-CD microparticles were characterized through Scanning Electron Microscopy (SEM) and it was demonstrated that they are highly efficient in the photodynamic therapy against a Streptococcus mutans (the main bacteria of cariogenic dental plaque) suspension, as a concentration of RB@α-CD µPs 10 times smaller than the usual concentration of pure RB is still capable to produce significant antibacterial activity.
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Fotoquimioterapia/métodos , Fármacos Fotosensibilizantes/farmacología , Rosa Bengala/farmacología , Streptococcus mutans/efectos de los fármacos , alfa-Ciclodextrinas/química , Biopelículas , Microscopía Electrónica de Rastreo , Tamaño de la Partícula , Fármacos Fotosensibilizantes/administración & dosificación , Rosa Bengala/administración & dosificación , Espectrofotometría InfrarrojaRESUMEN
A combined study of vibrational and thermodynamic properties of metaboric acid (BOH)3O3 crystal polymorphs α, ß, and γ were obtained through density functional theory (DFT) calculations in an attempt to resolve the conflicting assignments that currently exist in the literature for them. A complete correlation between the normal-mode assignment and vibrational signatures to distinguish particular features of each metaboric acid polymorph, in particular, those related to motions of the planar layers in α-(BOH)3O3, with a level of detail surpassing essays based on previous published experimental works has been achieved. Besides, no DFT-based research work was published early on the (BOH)3O3 polymorph vibrational properties, and our DFT-simulated infrared and Raman spectra for all metaboric acid polymorphs agree very well with experiment. Comparison of the previously published experimental IR and Raman spectroscopic results with predictions from higher levels DFT calculations allows identification of the in-plane and out-of-plane B-O bending modes. For example, the strongest measured (DFT-calculated) Raman modes of α-(BOH)3O3 at 591 and 797 cm-1 (599 and 810 cm-1) are identified as vibrational signatures of breathing B3O3/Ag in-plane modes, while the shoulder in the lattice modes region at 135 (143) cm-1 is the vibrational signature of the bending B3O3/B1g out-of-plane mode. Phonon-dispersion bands and their respective phonon densities of states were also evaluated for each system, as well as temperature-dependent curves for entropy, enthalpy, free energy, heat capacity, and Debye temperature. Phonon dispersion curves are singular for each (BOH)3O3 species, and a consistent gap decrease between the lowest and highest frequency vibrational bands was observed. The DFT-based calculations also revealed that the noncovalent interactions prevalent in the α and ß crystals lead to significant differences with respect to the thermodynamic properties in comparison with the γ phase.
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Boric acid (H3BO3) is being used effectively nowadays in traps/baits for the management of Aedes aegypti L. and Aedes albopictus Skuse species of mosquitoes, which are the main spreading vectors worldwide for diseases such as malaria, dengue, and zika. Previously, we published results on the structural, electronic, and optical properties of its molecular triclinic H3BO3-2A and trigonal H3BO3-3T polymorphs within the framework of density functional theory (DFT). Because of the renewed importance of these materials, the focus of this work is on the vibrational properties of the bulk boric acid 2A and 3T polymorphs. We measured the infrared and Raman spectra of the former, which was accompanied and interpreted through state-of-the-art DFT calculations, supplemented by computations regarding the H3BO3 molecule and two-dimensional layers based on the bulk structures. We identify/assign their normal modes and find vibrational signatures for each polymorph as well as in- and out-of-plane motions and molecular vibrations, unveiling a nice agreement between the DFT level of theory employed and our improved spectroscopic measurements in the wavenumber ranges of 400-2000 cm-1 (infrared) and 0-1500 cm-1 (Raman). We show that a dispersion-corrected DFT functional within the generalized gradient approximation (GGA) can be very accurate in describing the vibrational properties of the boric acid polymorphs. Besides, several issues left open/not clearly resolved in previously published works on the vibrational mode assignments of the bulk and 2D sheets of boric acid are explained satisfactorily. Finally, phonon dispersions and associated densities of states were also evaluated for each polymorph along with their temperature-dependent DFT-calculated entropy, enthalpy, free energy, heat capacity, and Debye temperature. In particular, our DFT calculations suggest a possible way to differentiate the 2A and 3T boric acid polymorphs through Raman spectroscopy and heat capacity measurements.
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AIMS: This study aimed to evaluate the in vitro activity of miltefosine and levamisole against strains of Coccidioides posadasii in the filamentous phase and strains of Histoplasma capsulatum in filamentous and yeast phases. METHODS AND RESULTS: Strains of C. posadasii in the filamentous phase (n = 22) and strains of H. capsulatum in filamentous (n = 40) and yeast phases (n = 13) were, respectively, submitted to broth macrodilution and broth microdilution methods, as described by the Clinical and Laboratory Standards Institute, to determine the minimum inhibitory concentration (MIC) and the minimum fungicidal concentration (MFC) of miltefosine and levamisole. The effect of the drugs on cell membrane permeability under osmotic stress conditions and total ergosterol production were also assessed, along with quantification of extravasated molecules. The results show the inhibitory effect of levamisole and miltefosine against C. posadasii and H. capsulatum and the effect of these drugs on ergosterol synthesis and the permeability of the plasma membrane using subinhibitory concentrations against strains subjected to osmotic stress. Levamisole was also able to cause the release of nucleic acids. CONCLUSIONS: Miltefosine and levamisole are capable of inhibiting the in vitro growth of C. posadasii and H. capsulatum, probably by altering the permeability of the cellular membrane. SIGNIFICANCE AND IMPACT OF THE STUDY: This work presents alternatives for the treatment of histoplasmosis and coccidioidomycosis, raising the possibility of the use of miltefosine and levamisole as adjuvants in antifungal therapy, providing perspectives for the design of in vivo studies.
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Antifúngicos/farmacología , Coccidioides/efectos de los fármacos , Ergosterol/biosíntesis , Histoplasma/crecimiento & desarrollo , Levamisol/farmacología , Fosforilcolina/análogos & derivados , Permeabilidad de la Membrana Celular/efectos de los fármacos , Coccidioides/crecimiento & desarrollo , Coccidioides/metabolismo , Histoplasma/efectos de los fármacos , Histoplasma/metabolismo , Pruebas de Sensibilidad Microbiana , Fosforilcolina/farmacologíaRESUMEN
Results of optical absorption measurements are presented together with calculated structural, electronic, and optical properties for the anhydrous monoclinic L-asparagine crystal. Density functional theory (DFT) within the generalized gradient approximation (GGA) including dispersion effects (TS, Grimme) was employed to perform the calculations. The optical absorption measurements revealed that the anhydrous monoclinic L-asparagine crystal is a wide band gap material with 4.95 eV main gap energy. DFT-GGA+TS simulations, on the other hand, produced structural parameters in very good agreement with X-ray data. The lattice parameter differences Δa, Δb, Δc between theory and experiment were as small as 0.020, 0.051, and 0.022 Å, respectively. The calculated band gap energy is smaller than the experimental data by about 15%, with a 4.23 eV indirect band gap corresponding to Z â Γ and Z â ß transitions. Three other indirect band gaps of 4.30 eV, 4.32 eV, and 4.36 eV are assigned to α3 â Γ, α1 â Γ, and α2 â Γ transitions, respectively. Δ-sol computations, on the other hand, predict a main band gap of 5.00 eV, just 50 meV above the experimental value. Electronic wavefunctions mainly originating from O 2p-carboxyl, C 2p-side chain, and C 2p-carboxyl orbitals contribute most significantly to the highest valence and lowest conduction energy bands, respectively. By varying the lattice parameters from their converged equilibrium values, we show that the unit cell is less stiff along the b direction than for the a and c directions. Effective mass calculations suggest that hole transport behavior is more anisotropic than electron transport, but the mass values allow for some charge mobility except along a direction perpendicular to the molecular layers of L-asparagine which form the crystal, so anhydrous monoclinic L-asparagine crystals could behave as wide gap semiconductors. Finally, the calculations point to a high degree of optical anisotropy for the absorption and complex dielectric function, with more structured curves for incident light polarized along the 100 and 101 directions.
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Asparagina/química , Teoría Cuántica , Cristalización , Fenómenos Ópticos , SemiconductoresRESUMEN
This study assessed the clinical effects and the mechanical antinociceptive potential of intravenous (IV) tramadol in horses.A blinded and randomized study was designed with 7 horses treated with 1 (Tr1), 2 (Tr2) or 3 (Tr3) mg kg-1 of tramadol IV. The heart rate, respiratory rate (fR), arterial pressure, degree of sedation, gastrointestinal motility (GI), behavior changes and the mechanical nociceptive threshold (MNT) were evaluated. The MNT was determined with von Frey device method.Tr3 had a significant increase in their fR and more pronounced behavioral changes than other treatments.The Tr1 showed a significant increase in arterial pressure. The GI reduced significantly, mainly in Tr2. The tramadol did not change the MNT of the horses.The clinical alterations observed with the different treatments were considered mild and transitory, being most evident in Tr2. However the tramadol did not have any analgesic effect with any of the doses evaluated.
Avaliaram-se os efeitos clínicos e o potencial antinociceptivo mecânico de diferentes doses de tramadol administradas por via intravenosa (IV) em equinos. Sete animais foram tratados com 1 (Tr1), 2 (Tr2) ou 3 (Tr3) mg kg-1de tramadol IV em um estudo cruzado do tipo cego e randomizado. Foram avaliados frequência cardíaca, frequência respiratória, temperatura retal, pressão arterial, nível de sedação, motilidade gastrointestinal, alterações comportamentais e limiar antinociceptivo mecânico (Von Frey). As principais alterações evidenciadas pela administração do tramadol concentram-se no aumento na frequência respiratória em Tr3, aumento significativo da pressão arterial em Tr1 e redução da motilidade gastrointestinal, mais pronunciada em Tr2. O tramadol não promoveu alteração significativa no limiar nociceptivo mecânico. As alterações clínicas observadas nos diferentes tratamentos foram consideradas leves e transitórias. Diante dos resultados, pode-se concluir que o tramadol não apresentou efeito antinociceptivo passível de ser avaliado pelo método empregado no presente estudo, em nenhum dos tratamentos.
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This study assessed the clinical effects and the mechanical antinociceptive potential of intravenous (IV) tramadol in horses.A blinded and randomized study was designed with 7 horses treated with 1 (Tr1), 2 (Tr2) or 3 (Tr3) mg kg-1 of tramadol IV. The heart rate, respiratory rate (fR), arterial pressure, degree of sedation, gastrointestinal motility (GI), behavior changes and the mechanical nociceptive threshold (MNT) were evaluated. The MNT was determined with von Frey device method.Tr3 had a significant increase in their fR and more pronounced behavioral changes than other treatments.The Tr1 showed a significant increase in arterial pressure. The GI reduced significantly, mainly in Tr2. The tramadol did not change the MNT of the horses.The clinical alterations observed with the different treatments were considered mild and transitory, being most evident in Tr2. However the tramadol did not have any analgesic effect with any of the doses evaluated.(AU)
Avaliaram-se os efeitos clínicos e o potencial antinociceptivo mecânico de diferentes doses de tramadol administradas por via intravenosa (IV) em equinos. Sete animais foram tratados com 1 (Tr1), 2 (Tr2) ou 3 (Tr3) mg kg-1de tramadol IV em um estudo cruzado do tipo cego e randomizado. Foram avaliados frequência cardíaca, frequência respiratória, temperatura retal, pressão arterial, nível de sedação, motilidade gastrointestinal, alterações comportamentais e limiar antinociceptivo mecânico (Von Frey). As principais alterações evidenciadas pela administração do tramadol concentram-se no aumento na frequência respiratória em Tr3, aumento significativo da pressão arterial em Tr1 e redução da motilidade gastrointestinal, mais pronunciada em Tr2. O tramadol não promoveu alteração significativa no limiar nociceptivo mecânico. As alterações clínicas observadas nos diferentes tratamentos foram consideradas leves e transitórias. Diante dos resultados, pode-se concluir que o tramadol não apresentou efeito antinociceptivo passível de ser avaliado pelo método empregado no presente estudo, em nenhum dos tratamentos.(AU)
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Animales , Tramadol/uso terapéutico , Tramadol/administración & dosificación , Enfermedades de los Caballos , Analgesia/veterinariaRESUMEN
This study aimed at evaluating the in vitro antifungal susceptibility of Candida albicans isolates obtained during necropsy of a wild Brazilian porcupine and the mechanism of azole resistance. Initially, we investigated the in vitro susceptibility of the three isolates to amphotericin B, caspofungin, fluconazole, itraconazole, ketoconazole and voriconazole. Afterwards, three sub-inhibitory concentrations (47, 21 and 12 mg/l) of promethazine, an efflux pump inhibitor, were tested in combination with the antifungal drugs in order to evaluate the role of these pumps in the development of antifungal resistance. In addition, the three isolates were submitted to RAPD-PCR and M13-fingerprinting analyses. The minimum inhibitory concentrations (MICs) obtained with the isolates were 1, 0.03125, 250, 125, 8 and 250 mg/l for amphotericin B, caspofungin, fluconazole, itraconazole, ketoconazole and voriconazole, respectively, and the isolates were found to be resistant to all tested azoles. The addition of the three subinhibitory concentrations of promethazine resulted in statistically significant (P < 0.05) reductions in the MICs for all tested drugs, with decreases to azoles being statistically greater than those for amphotericin B and caspofungin (P < 0.05). The molecular analyses showed a genetic similarity among the three tested isolates, suggesting the occurrence of candidemia in the studied animal. These findings highlight the importance of monitoring antifungal susceptibility of Candida spp. from veterinary sources, especially as they may indicate the occurrence of primary azole resistance even in wild animals.
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Antifúngicos/farmacología , Azoles/farmacología , Candida albicans/efectos de los fármacos , Candida albicans/aislamiento & purificación , Farmacorresistencia Fúngica , Puercoespines/microbiología , Animales , Brasil , Candida albicans/clasificación , Candida albicans/genética , Pruebas de Sensibilidad Microbiana , Tipificación Molecular , Técnicas de Tipificación Micológica , Técnica del ADN Polimorfo Amplificado AleatorioRESUMEN
This study evaluated the in vitro interaction between ciprofloxacin (CIP) and classical antifungals against Histoplasma capsulatum var. capsulatum in mycelial (n = 16) and yeast-like forms (n = 9) and Coccidioides posadasii in mycelial form (n = 16). This research was conducted through broth microdilution and macrodilution, according to Clinical Laboratory Standards Institute. Inocula were prepared to obtain from 0.5 × 10(3) to 2.5 × 10(4) cfu ml(-1) for H. capsulatum and from 10(3) to 5 × 10(3) cfu ml(-1) for C. posadasii. Initially, minimum inhibitory concentration (MIC) for each drug alone was determined. Then, these MICs were used as the highest concentration for each drug during combination assays. The procedures were performed in duplicate. For all combination assays, MICs were defined as the lowest concentration capable of inhibiting 80% of visible fungal growth, when compared to the drug-free control. Drug interaction was evaluated by paired sample t-Student test. The obtained data showed a significant MIC reduction for most tested combinations of CIP with antifungals, except for that of CIP and voriconazole against yeast-like H. capsulatum. This study brings potential alternatives for the treatment of histoplasmosis and coccidioidomycosis, raising the possibility of using CIP as an adjuvant antifungal therapy, providing perspectives to delineate in vivo studies.
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Antifúngicos/farmacología , Ciprofloxacina/farmacología , Coccidioides/efectos de los fármacos , Histoplasma/efectos de los fármacos , Caspofungina , Coccidioides/crecimiento & desarrollo , Evaluación Preclínica de Medicamentos , Sinergismo Farmacológico , Equinocandinas/farmacología , Histoplasma/crecimiento & desarrollo , Lipopéptidos , Pruebas de Sensibilidad Microbiana , Micelio/efectos de los fármacos , Pirimidinas/farmacología , Triazoles/farmacología , VoriconazolRESUMEN
We present the structural, electronic, and optical properties of anhydrous crystals of DNA nucleobases (guanine, adenine, cytosine, and thymine) found after DFT (Density Functional Theory) calculations within the local density approximation, as well as experimental measurements of optical absorption for powders of these crystals. Guanine and cytosine (adenine and thymine) anhydrous crystals are predicted from the DFT simulations to be direct (indirect) band gap semiconductors, with values 2.68 eV and 3.30 eV (2.83 eV and 3.22 eV), respectively, while the experimentally estimated band gaps we have measured are 3.83 eV and 3.84 eV (3.89 eV and 4.07 eV), in the same order. The electronic effective masses we have obtained at band extremes show that, at low temperatures, these crystals behave like wide gap semiconductors for electrons moving along the nucleobases stacking direction, while the hole transport are somewhat limited. Lastly, the calculated electronic dielectric functions of DNA nucleobases crystals in the parallel and perpendicular directions to the stacking planes exhibit a high degree of anisotropy (except cytosine), in agreement with published experimental results.
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Adenina/química , Citosina/química , Guanina/química , Semiconductores , Timina/química , Cristalización , ADN/química , Modelos Moleculares , Agua/químicaRESUMEN
CdSnO(3) ilmenite and perovskite crystals were investigated using both the local density and generalized gradient approximations, LDA and GGA, respectively, of the density functional theory (DFT). The electronic band structures, densities of states, dielectric functions, optical absorption and reflectivity spectra related to electronic transitions were obtained, as well as the infrared absorption spectra after computing the vibrational modes of the crystals at q = 0. Dielectric optical permittivities and polarizabilities at ω = 0 and ∞ were also calculated. The results show that GGA-optimized geometries are more accurate than LDA ones, and the Kohn-Sham band structures obtained for the CdSnO(3) polymorphs confirm that ilmenite has an indirect band gap, while perovskite has a direct band gap, both being semiconductors. Effective masses for both crystals are obtained for the first time, being highly isotropic for electrons and anisotropic for holes. The optical properties reveal a very small degree of anisotropy of both crystals with respect to different polarization planes of incident light. The phonon calculation at q = 0 for perovskite CdSnO(3) does not show any imaginary frequencies, in contrast to a previous report suggesting the existence of a more stable crystal of perovskite CdSnO(3) with ferroelectric properties.
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Compuestos de Cadmio/química , Compuestos de Calcio/química , Electrones , Hierro/química , Fenómenos Ópticos , Óxidos/química , Teoría Cuántica , Compuestos de Estaño/química , Titanio/química , Absorción , Impedancia Eléctrica , Modelos Moleculares , Conformación Molecular , Espectrofotometría InfrarrojaRESUMEN
AIMS: To investigate the presence of fungi during three human decomposition stages: bloated, putrefaction and skeletonization. METHODS AND RESULTS: The samples were gathered in the city of Fortaleza, Ceará, Brazil, from the public morgue and cemeteries. The material was submitted to conventional mycological procedures by direct examination and macro/micro morphological and biochemical analyses. The main fungi isolated were Aspergillus spp., Penicillium spp. and Candida spp. in the bloated stage (n = 34 cadavers) and in the putrefaction stage (n = 6 cadavers), while in the skeletonization stage (n = 20 cadavers), the main fungi were Aspergillus spp., Penicillium spp. and Mucor sp. CONCLUSIONS: Aspergillus, Penicillium and Candida species were associated with decomposed human cadavers. SIGNIFICANCE AND IMPACT OF THE STUDY: These findings enable tracing out the profile of fungal communities of human cadavers for the first time. However, much more research will be necessary to develop this new segment of mycology and to enable its routine use in forensic science.
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Ecosistema , Ciencias Forenses , Hongos Mitospóricos/fisiología , Cambios Post Mortem , Aspergillus/aislamiento & purificación , Aspergillus/fisiología , Biodiversidad , Brasil , Candida/aislamiento & purificación , Candida/fisiología , Humanos , Hongos Mitospóricos/aislamiento & purificación , Penicillium/aislamiento & purificación , Penicillium/fisiologíaRESUMEN
C(60)-derived nanobaskets, with chemical formulae (symmetry point group) C(40)H(10) (C(5v)), C(39)H(12) (C(3v)), C(46)H(12) (C(2v)), were investigated. Molecular dynamic simulations (MDSs) indicate that the molecules preserve their bonding frame for temperatures up to 300 K (simulation time 100 ps), and maintain atomic cohesion for at least 4 ps at temperatures up to 3500 K. The infrared spectra of the C(60)-derived nanobaskets were simulated through density functional theory (DFT) calculations, allowing for the attribution of infrared signatures specific to each carbon nanobasket. The possibility of using C(60)-derived nanobaskets as molecular containers is demonstrated by performing a DFT study of their bonding to hydrogen, water, and L-alanine. The carbon nanostructures presented here show a higher bonding energy (approximately 1.0 eV), suggesting that a family of nanostructures, C(n)-derived (n = 60,70,76,80, etc) nanobaskets, could work as molecular containers, paving the way for future developments such as tunable traps for complex molecular systems.
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We present some computational simulations of graphene-based nanoribbons with a number of half-twists varying from 0 to 4 and two types of defects obtained by removing a single carbon atom from two different sites. Optimized geometries are found by using a mix of classical quantum semiempirical computations. According with the simulations results, the local curvature of the nanoribbons increases at the defect sites, especially for a higher number of half-twists. The HOMO-LUMO energy gap of the nanostructures has significant variation when the number of half-twists increases for the defective nanoribbons. At the quantum semiempirical level, the first optically active transitions and oscillator strengths are calculated using the full configuration interaction (CI) framework, and the optical absorption in the UV/vis range (electronic transitions) and in the infrared (vibrational transitions) are achieved. Distinct nanoribbons show unique spectral signatures in the UV/vis range, with the first absorption peaks in wavelengths ranging from the orange to the violet. Strong absorption is observed in the ultraviolet region, although differences in their infrared spectra are hardly discernible.
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Adsorption of ascorbic acid (AsA) on C60 is investigated using classical molecular mechanics and density functional theory (DFT). Classical annealing was performed to explore the space of molecular configurations of ascorbic acid adsorbed on C60, searching for optimal geometries. From the structure with the smallest total energy, 10 initial configurations were prepared by applying rotations of 90 degrees about three orthogonal axes. Each one of these configurations was optimized using DFT (for both LDA and GGA exchange-correlation functionals), and an estimate of their total and adsorption energies was found. Different configurations have minimal adsorption energies (defined here as the total energy of the adsorbate minus the total energy of the separate molecules) from -0.54 to -0.10 eV, with distinct optimal distances between the AsA and C60 centers of mass. According to a Hirshfeld population analysis, AsA is, in general, an acceptor of electrons from C60. Our results demonstrate the feasibility of noncovalent functionalization of C60 with AsA and provide minimal energy values for the several different configurations investigated. These results should be considered in reactions as a possible way to prevent against the oxidative damage and toxicity of C60. The beneficial effects of using AsA-C60 includes its action when administered together with levodopa, against the neurotoxicity generated by levodopa isolated, which opens new strategies for the Parkinson's disease treatment.