Instituto Superior Of Tecnologias Y Ciencias Aplicadas Instec

Havana, Cuba

Instituto Superior Of Tecnologias Y Ciencias Aplicadas Instec

Havana, Cuba
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Ferreira D.M.,University of Sao Paulo | Saga Y.Y.,University of Sao Paulo | Aluicio-Sarduy E.,Instituto Superior Of Tecnologias Y Ciencias Aplicadas Instec | Tedesco A.C.,University of Sao Paulo
Current Medicinal Chemistry | Year: 2013

For some time Photodynamic Therapy and electrochemotherapy have been used as alternative therapies against skin cancer. The primary aim of this work was to develop, characterize, and evaluate the in vitro cytotoxic activity of new drug delivery systems based on chitosan nanoparticles containing aminolevulinic acid derivatives such as prodrug (5-ALA and its ester derivative 8-ALA). The second goal of this study was to evaluate the synergistic effect of a combination of classical Photodynamic Therapy and electrochemotherapy, which is routinely utilized to modulate and enhance the permeation of photosensitizers, prodrugs, and other active compounds through the skin, improving the efficiency of PDT in the treatment of cutaneous neoplasms. © 2013 Bentham Science Publishers.


Rodriguez-Donis I.,Instituto Superior Of Tecnologias Y Ciencias Aplicadas Instec | Gerbaud V.,National Polytechnic Institute of Toulouse | Gerbaud V.,French National Center for Scientific Research | Joulia X.,National Polytechnic Institute of Toulouse | Joulia X.,French National Center for Scientific Research
Industrial and Engineering Chemistry Research | Year: 2012

This paper shows how knowledge of the univolatility and unidistribution line location and residue curve analysis help to assess the feasibility of batch extractive rectifying or stripping distillation of azeotropic mixtures by using an intermediate boiling entrainer. We consider five minimum boiling (minT) azeotropic mixtures AB with entrainer E, namely, acetone-heptane with benzene, methanol-toluene with triethylamine, methyl acetate-cyclohexane with carbon tetrachloride, dichloromethane-ethanol with acetone, and ethyl acetate-heptane with benzene; and one maximum boiling (maxT) azeotropic mixture, namely, chloroform-ethyl acetate with either 2-chlorobutane, isobutylchloride, bromopropane, or bromochloromethane. All ternary diagrams A-B-E belong to the 1.0-1b class, for which all three possible univolatility, α AB, α BE, and α AE, and unidistribution lines, K A, K B, and K E can exist. With application of the general feasibility criterion of Rodriguez-Donis et al. (Ind. Eng. Chem. Res. 2009, 48 (7), 3544-3559), both azeotropic components, A and B, accomplish the criterion, and they can be recovered, A in an extractive rectifier and B in an extractive stripper. The process efficiency of each alternative depends strongly on the location of the α AB univolatility line interception with the triangle edge, and also depends on the α BE (α AE) in the minT (maxT) case and of the unidistribution line K E closeness to the (E-B) (A-E) edge. Besides, choice of the rectification of A instead of the stripping of B is set by the ratio of α AE/α BE, the ratio of relative volatility variation of the binary mixtures between A or B and E. © 2012 American Chemical Society.


Rodriguez-Donis I.,Instituto Superior Of Tecnologias Y Ciencias Aplicadas Instec | Gerbaud V.,National Polytechnic Institute of Toulouse | Gerbaud V.,French National Center for Scientific Research | Joulia X.,National Polytechnic Institute of Toulouse | Joulia X.,French National Center for Scientific Research
Industrial and Engineering Chemistry Research | Year: 2012

This article shows how knowledge of the location of univolatility lines and residue curve analysis helps in assessing the feasibility of extractive distillation of minimum-boiling (minT) or maximum-boiling (maxT) azeotropic mixtures or low-relative-volatility (low-α) mixtures (A-B) by using a light-boiling entrainer (E), in accordance with the general feasibility criterion of Rodriguez-Donis et al. [ Ind. Eng. Chem. Res. 2009, 48 (7), 3544-3559 ]. Considering all possible locations of the univolatility line α AB, three minT azeotropic mixtures with a light entrainer (1.0-2 class), namely, ethanol-water with methanol, ethanol-toluene with acetone, and methyl ethyl ketone-benzene with acetone; three maxT azeotropic mixtures with a light entrainer (1.0-1a class), namely, water-ethylenediamine with methanol, acetone-chloroform with dichlomethane, and propanoic acid-dimethyl formamide with methyl isobutyl ketone; and one low-α mixture with a light entrainer (0.0-1 class), namely, ethyl acetate-benzene with acetone, were studied in a stripping extractive column. For the 1.0-2 class, both A and B can be recovered as the bottom product, depending on the location of α AB = 1, which sets limiting values for the entrainer feed flow rate F E/L T for one of the product. In addition, the feasible region of the extractive distillation process is larger than for the azeotropic distillation process. For the 1.0-1a class, the product is either A or B, depending on the location of α AB = 1, which sets a minimum value of (F E/L T) min for one of the product. For the 0.0-1 class, feasibility depends on the existence α AB = 1. When it does not exist, B is the unique possible product. When it does, both A and B are products, with B below a maximum value of (F E/L T) max,B and A above a minimum value (F E/L T) min,A. © 2011 American Chemical Society.


Barreto A.A.,Instituto Superior Of Tecnologias Y Ciencias Aplicadas Instec | Rodriguez-Donis I.,Instituto Superior Of Tecnologias Y Ciencias Aplicadas Instec | Gerbaud V.,National Polytechnic Institute of Toulouse | Gerbaud V.,French National Center for Scientific Research | And 2 more authors.
Industrial and Engineering Chemistry Research | Year: 2011

Heterogeneous extractive batch distillation of the chloroform-methanol minimum-boiling-temperature azeotropic mixture is studied with water as a heterogeneous entrainer. The continuous feeding of water allows recovery of 99 mol % chloroform after condensation of the saddle binary heteroazeotrope water-chloroform. Unlike a homogeneous process, the reflux composition is different from the heteroazeotrope water-chloroform in the vapor overhead. Besides, the distillate recovery is improved by refluxing a portion α of the chloroform-rich distillate phase along with the water-rich entrainer phase. A genetic algorithm is coupled to a constant molar overflow model to study seven operation policies. Optimization parameters are the entrainer flow rate F E/V, the portion αT3 of the distillate-rich phase refluxed to the column during chloroform distillation, and the reflux policy RT5 during methanol distillation. The optimization maximizes a profit function, penalized with recovery yield constraints, whereas purity targets are used as task ending events. All optimized solutions achieve higher than 90 mol % recovery yields and 99 mol % purity for both products chloroform and methanol. The results are confirmed by rigorous simulation showing the good performance of coupling a simplified model and a genetic algorithm as a first approach. The two-piece-wise parameter value operation policies for all three parameters increase profit by 41.8% and reduce total time by 43.8% compared to the single value parameter policy. The parameter influence study ranks RT5 first, αT3 second, and FE/V last. Keeping F E/V constant and using the two-piece-wise αT3 and RT5 value operation is recommended to increase profit. © 2011 American Chemical Society.


Acosta Avalo J.L.,Instituto Superior Of Tecnologias Y Ciencias Aplicadas Instec | Perez Rojas H.,Institute Cibernetica
Nuclear Physics B | Year: 2016

We report the generation of a pseudovector electric current having imbalanced chirality in an electron-positron strongly magnetized gas in QED. It propagates along the external applied magnetic field B as a chiral magnetic effect in QED. It is triggered by a perturbative electric field parallel to B, associated to a pseudovector longitudinal mode propagating along B. An electromagnetic chemical potential was introduced, but our results remain valid even when it vanishes. A nonzero fermion mass was assumed, which is usually considered vanishing in the literature. In the quantum field theory formalism at finite temperature and density, an anomaly relation for the axial current was found for a medium of massive fermions. It bears some analogy to the Adler-Bell-Jackiw anomaly. From the expression for the chiral current in terms of the photon self-energy tensor in a medium, it is obtained that electrons and positrons scattered by longitudinal photons (inside the light cone) contribute to the chiral current, as well as the to pair creation due to longitudinal photons (out of light cone). In the static limit, an electric pseudovector current is obtained in the lowest Landau level. © 2016 The Authors.


Delgado-Magnero K.H.,University of Habana | Valiente P.A.,University of Habana | Ruiz-Pena M.,Instituto Superior Of Tecnologias Y Ciencias Aplicadas Instec | Perez-Gramatges A.,Pontifical Catholic University of Rio de Janeiro | Pons T.,Spanish National Cancer Research Center
Colloids and Surfaces B: Biointerfaces | Year: 2014

To gain a better understanding of the interactions governing the binding mechanism of proteins with non-ionic surfactants, the association processes of Tween 20 and Tween 80 with the bovine serum albumin (BSA) protein were investigated using molecular dynamics (MD) simulations. Protein:surfactant molar ratios were chosen according to the critical micelle concentration (CMC) of each surfactant in the presence of BSA. It was found that both the hydrophilic and the hydrophobic groups of the BSA equally contribute to the surface area of interaction with the non-ionic surfactants. A novel theoretical model for the interactions between BSA and these surfactants at the atomic level is proposed, where both surfactants bind to non-specific domains of the BSA three-dimensional structure mainly through their polyoxyethylene groups, by hydrogen bonds and van der Waals interactions. This is well supported by the strong electrostatic and van der Waals interaction energies obtained in the calculations involving surfactant polyoxyethylene groups and different protein regions. The results obtained from the MD simulations suggest that the formation of surfactant clusters over the BSA structure, due to further cooperative self-assembly of Tween molecules, could increase the protein conformational stability. These results extend the current knowledge on molecular interactions between globular proteins and non-ionic surfactants, and contribute to the fine-tuning design of protein formulations using polysorbates as excipients for minimizing the undesirable effects of protein adsorption and aggregation. © 2013 Elsevier B.V.


Uranga-Pina L.,University of Habana | Meier C.,University Paul Sabatier | Rubayo-Soneira J.,Instituto Superior Of Tecnologias Y Ciencias Aplicadas Instec
Chemical Physics Letters | Year: 2012

Photoexcitation of NO embedded in rare gas matrices triggers a shock-wave like radial perturbation of the surrounding rare gas atoms. In this Letter, we present quantum dynamical studies of this process, based on a radial shell model. The high-dimensional quantum dynamics is preformed with the multi-configuration time dependent Hartree (MCTDH) method. By comparison with time-dependent Hartree (TDH) results, we study the effects of dynamical correlations. Their inclusion modifies the high-dimensional wavefunction, however, mean values are well described within the TDH ansatz. Finally, pump-probe signals are simulated and shown to lead to small but measurable effects when including the correlations. © 2012 Elsevier B.V. All rights reserved.


Batista-Leyva A.J.,Instituto Superior Of Tecnologias Y Ciencias Aplicadas Instec | Ruiz-Suarez J.C.,CINVESTAV
European Physical Journal E | Year: 2016

Abstract.: We study how a magnetic bead bounces onto a horizontal diamagnetic conducting plane. The bead, falling down by gravity from a certain height, produces an Eddy current that creates a repelling force. For low velocities the bead is trapped by the surface, for intermediate ones it escapes. In such a case the induced current changes its sign, and so does the force. The balance between diamagnetic and viscoelastic interactions determines the bouncing dynamics. We find experimentally the restitution coefficient as a function of the impact speed of the bead and develop, taking into account simple energetic considerations, a model able to reproduce our findings. Graphical abstract: [Figure not available: see fulltext.] © 2016, EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg.


Augier A.G.,Instituto Superior Of Tecnologias Y Ciencias Aplicadas Instec | Sanchez R.B.,Instituto Superior Of Tecnologias Y Ciencias Aplicadas Instec
Optics Communications | Year: 2011

We presented "hologravure" as the generalization of a scratch hologram, generated by computer from a three-dimensional (3D) model by using an appropriate software, and laser-drawing with a conventional engraver-laser system. For making this type of computer-generated hologram, neither diffractive optics, nor mask pattern or photo-reduction of a transparency onto a high resolution film plate is needed. The shape of a 3D virtual object is encoded in a two-dimensional (2D) multiple circular-scratch drawing. A computer program was created for generating the holograms. Hologravures representing several 3D models are engraved on different materials, and the quality of the lines traced by the CO2 laser is considered. Sheets of acrylic, polycarbonate, glass and thermo-resistant pieces of acetate were tested. Reconstructed images of all this computer-generated and laser engraved holograms and also of computer assisted and hand-drawn scratch holograms, synthesized by means of the same software are shown. © 2010 Elsevier B.V. All rights reserved.


Acosta Avalo J.L.,Instituto Superior Of Tecnologias Y Ciencias Aplicadas Instec | Perez Rojas H.,Institute Cibernetica Matem atica y Fisica ICIMAF
Astronomische Nachrichten | Year: 2015

We demonstrate the existence of a chiral magnetic effect in an electron-positron magnetized gas in QED. A vector current is induced by the electric field related to the pseudo-vector longitudinal Debye massive photon mode propagating along the external magnetic field B and separating opposite charges of the same helicity. A equation associated to the nonconservation of the axial current is obtained in a medium of massive and magnetized charged fermions. The effect is interesting in connection to the QCD chiral magnetic case reported in current literature. (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim). Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

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