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De Faria A.J.,Federal University of Alfenas
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2016

An optical procedure in the context of continuous variables to verify bipartite entanglement without destroying both systems and their entanglement is proposed. To perform the nondestructive verification of entanglement, the method relies on beam-splitter and quantum nondemolition (QND) interactions of the signal modes with two ancillary probe modes. The probe modes are measured by homodyne detections, and the obtained information is used to feed forward modulation of signal modes, concluding the procedure. Characterizing the method by figures of merit used in QND processes, we can establish the conditions for an effectively quantum scheme. Based on such conditions, it is shown that the classical information acquired from the homodyne detections of probe modes is sufficient to verify the entanglement of the output signal modes. The processing impact due to added noise on the output entanglement is assessed in the case of Gaussian modes. © 2016 American Physical Society. Source

Ribeiro-Junior N.V.,Federal University of Alfenas
The International journal of periodontics & restorative dentistry | Year: 2013

Excessive gingival display during smiling ("gummy smile") is an esthetic issue that affects a considerable part of the population. The hyperactivity of the elevator muscle of the upper lip is one of the main causes of a gummy smile, and several techniques have been proposed for its treatment. The aim of this report is to describe a modification of the lip repositioning technique to achieve stable and significant outcomes through a more conservative procedure. Two patients complaining about a gummy smile were treated with the proposed technique and presented, after a 6-month follow-up, significant improvement in the amount of gingival exposure and esthetic satisfaction. Source

Morbec J.M.,Federal University of Alfenas | Rahman G.,Quaid-i-Azam University
Physical Review B - Condensed Matter and Materials Physics | Year: 2013

Using ab initio calculations based on density functional theory, we investigate the effects of vacancies on the electronic and magnetic properties of zigzag SiC nanoribbons (Z-SiCNR). Single (VC and VSi) and double (VSiVSi and VSiVC) vacancies are observed to induce magnetism in Z-SiCNRs. The presence of a single VSi does not affect the half-metallic behavior of pristine Z-SiCNRs; however, a single VC leads to a transition from half-metallic to metallic behavior in Z-SiCNRs due to the edge Si p orbitals and the atoms surrounding the vacancy. The interactions of vacancies with foreign impurity atoms (B and N) are also investigated, and it is observed that V SiNC not only suppresses the oscillatory type magnetism of VSiVC but also retains the half-metallic character of the pristine Z-SiCNRs. The defect formation energies of vacancies can be reduced by substitutional B and N atoms. We believe that ferromagnetism is expected if Z-SiCNRs are grown under suitable conditions. © 2013 American Physical Society. Source

Dias K.S.T.,Federal University of Alfenas | Viegas C.,Federal University of Alfenas
Current Neuropharmacology | Year: 2014

Alzheimer’s disease (AD) is a complex neurodegenerative disorder with a multi-faceted pathogenesis. So far, the therapeutic paradigm “one-compound-one-target” has failed and despite enormous efforts to elucidate the pathophysiology of AD, the disease is still incurable. The multiple factors involved in AD include amyloid aggregation to form insoluble neurotoxic plaques of Aβ, hyperphosphorylation of tau protein, oxidative stress, calcium imbalance, mitochondrial dysfunction and deterioration of synaptic transmission. These factors together, accentuate changes in the CNS homeostasis, starting a complex process of interconnected physiological damage, leading to cognitive and memory impairment and neuronal death. A recent approach for the rational design of new drug candidates, also called multitarget-directed ligand (MTDL) approach, has gained increasing attention by many research groups, which have developed a variety of hybrid compounds acting simultaneously on diverse biological targets. This review aims to show some recent advances and examples of the exploitation of MTDL approach in the rational design of novel drug candidate prototypes for the treatment of AD. © 2014 Bentham Science Publishers. Source

Damas G.B.,Federal University of Alfenas | Dias A.B.A.,Federal University of Alfenas | Costa L.T.,Federal University of Fluminense
Journal of Physical Chemistry B | Year: 2014

In recent years, the global climate change is in evidence and it is almost a consensus that it is caused by the greenhouse gases emissions. An alternative to reduce these emissions is carbon capture and storage (CCS), which employs solvents based on amine compounds. In this scene, ionic liquids (IL) have been investigated to a greater extent for this application. In this work, we make an evaluation of interactions between gases (CO2, SO2, and H2S) and anion/cation from IL, as well as cation-anion interactions. For this, quantum calculations under vacuum were performed at the B3LYP/6-311+G-* level of theory and using the M06-2X functional, where dispersion effects are considered. Among the well-studied systems based on imidazolium cations and fluorinated anions, we also studied the tetraalkylammonium, tetraalkylphosphonium, ether-functionalized imidazolium based systems, and tetrahexylammonium bis(trifluoromethanesulfonyl)imide, [THA][Tf2N], as a potential prototype. The ion pairs evaluated include [Tf2N]--based IL, with alkyl chain varying from [C1mim]+ to [C8mim]+ and [C 1mim]+-based IL. We found that the anion becomes more available to interact with gas with the weakening of the cation-anion interaction. [THA][Tf2N] has a binding energy of -274.89 kJ/mol at the B3LYP/6-311+G** level of theory, which is considered energetically interesting to gas capture applications. © 2014 American Chemical Society. Source

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