Novel Antimicrobial Peptides Bacterial Cellulose Obtained by Symbioses Culture Between Polyhexanide Biguanide (PHMB) and Green Tea

Bacterial cellulose is a highly hydrated pellicle made up of a random assembly of ribbon shaped fibers less than 5 nm wide. The unique properties provided by the nanometric structure have led to a number of diagnostic biological probes, display devices due to their unique size-dependent medical applications. Bacterial cellulose matrix extracellular is a novel biotechnology and unique medicine indicated for ultimate chronic wound treatment management, drug delivery, tissue engineering, skin cancer and offers an actual and effective solution to a serious medical and social problem and to promote rapid healing in lesions caused by Diabetic burns, ulcers of the lower limbs or any other circumstance in which there's epidermal or dermal loss. In this work, it is reported novel antimicrobial peptides (AMPs) bacterial cellulose/polyhexanide biguanide (PHMB) which are produced by symbioses culture between polyhexanide biguanide and green tea culture medium resulting in the pure 3-D structure consisting of an ultra-fine network of novel biocellulose/PHMB nanofibres matrix (2-8 nm), highly hydrated (99% in weight), and with higher molecular weight, full biocompatibility.

Ag-rich precipitates formation in the Cu-11%Al-10%Mn-3%Ag alloy

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The physicochemical characterization and in vivo response of micro/nanoporous bioactive ceramic particulate bone graft materials

In this study, the physicochemical characteristics of calcium phosphate based bioactive ceramics of different compositions and blends presenting similar micro/nanoporosity and micrometer scale surface texture were characterized and evaluated in an in vivo model. Prior to the animal experiment, the porosity, surface area, particle size distribution, phase quantification, and dissolution of the materials tested were evaluated. The bone regenerative properties of the materials were evaluated using a rabbit calvaria model. After 2, 4, and 8 weeks, the animals were sacrificed and all samples were subjected to histologic observation and histomorphometric analysis. The material characterization showed that all materials tested presented variation in particle size, porosity and composition with different degrees of HA/TCP/lower stoichiometry phase ratios. Histologically, the calvarial defects presented temporal bone filling suggesting that all material groups were biocompatible and osteoconductive. Among the different materials tested, there were significant differences found in the amount of bone formation as a function of time. At 8 weeks, the micro/nanoporous material presenting similar to 55,TCP:45%,HA composition ratio presented higher amounts of new bone regeneration relative to other blends and a decrease in the amount of soft tissue infiltration. (C) 2014 Elsevier B.V. All rights reserved.

Quantum coherence and uncertainty in the anisotropic XY chain

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Evolution of Goldstone mode in binary condensate mixtures

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Temperature-induced spontaneous time-reversal symmetry breaking on the honeycomb lattice

Phase transitions involving spontaneous time-reversal symmetry breaking are studied on the honeycomb lattice at finite hole doping with next-nearest-neighbor repulsion. We derive an exact expression for the mean-field equation of state in closed form, valid at temperatures much less than the Fermi energy. Contrary to standard expectations, we find that thermally induced intraband particle-hole excitations can create and stabilize a uniform metallic phase with broken time-reversal symmetry as the temperature is raised in a region where the ground state is a trivial metal.

Factorization and criticality in the anisotropic XY chain via correlations

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Amorphous ZrF4-a molecular dynamics study

Using an effective two-body interaction potential, a molecular dynamics study of the structural properties of amorphous ZrF4 phase is presented. The effective pair potential includes steric repulsion, Coulomb interaction due to charge transfer, and charge-dipole interaction due to the large electronic polarizability of anions. The results for structural correlations, such as pair distribution functions, coordination numbers, and bond angle distributions are presented. Excellent agreement is obtained by comparing experimental X-ray diffraction and the simulated static X-ray structure factor. © 1993.

A Monte Carlo study of the anisotropic N=3 Ashkin-Teller model

The phase diagram of an asymmetric N = 3 Ashkin-Teller model is obtained by a numerical analysis which combines Monte Carlo renormalization group and reweighting techniques. Present results reveal several differences with those obtained by mean-field calculations and a Hamiltonian approach. In particular, we found Ising critical exponents along a line where Goldschmidt has located the Kosterlitz-Thouless multicritical point. On the other hand, we did find nonuniversal exponents along another transition line. Symmetry breaking in this case is very similar to the N = 2 case, since the symmetries associated to only two of the Ising variables are broken. However, for large values of the coupling constant ratio XW = W/K, when the only broken symmetry is of a hidden variable, we detected first-order phase transitions giving evidence supporting the existence of a multicritical point, as suggested by Goldschmidt, but in a different region of the phase diagram. © 2002 Elsevier Science B.V. All rights reserved.

Dielectric properties of Sr0.75Ba0.25Nb 2O6 thin films: Bias field, frequency and temperature dependence

Ferroelectric strontium barium niobate solid solutions had received great attention due to their excellent pyroelectric, electrooptic and photorefractive properties. Furthermore, they usually also present very interesting phase transition characteristics. In this work, polycrystalline single phase Sr 0.75 Ba 0.25 Nb 2 O 6 thin films were prepared by a hybrid chemical method and deposited on Pt/Ti/SiO 2 /Si substrates. The temperature dependence of dielectric constant was measured at different frequencies and bias field levels. The presence of two dielectric dispersion regions with relaxor characteristics was observed at distinct temperature ranges, corresponding to the ferro-paraelectric and to a structural phase transition at low temperatures, respectively. A specific dielectric dispersion region, associated with an incommensurate superstructure frequently observed in bulk samples, was not observed in this films probably due to their small grain sizes. © 2002 Taylor & Francis.

Dilatometria de sólidos com resolução subatômica

The main goal of this bachelor work is the study of the physical properties of solids by thermal expansion coefficient measurements, which allows the exploration of various aspects of phase transitions. In this study, some theoretical aspects were focused, for example the first and second order phase transitions, Landau theory for phase transition and the volumetric thermal expansion coefficient. Furthermore, on the origin of the thermal expansion from the Lennard-Jones potential, that contains the anharmonic terms, which give rise to the phononic thermal expansion in solids

Investigação das propriedades de transporte da fase ferroelétrica de Mott-Hubbard em condutores moleculares

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

A New Cryptographic Scheme for Securing Dynamic Conferences in Data Networks

Dynamic conferencing refers to a scenario wherein any subset of users in a universe of users form a conference for sharing confidential information among themselves. The key distribution (KD) problem in dynamic conferencing is to compute a shared secret key for such a dynamically formed conference. In literature, the KD schemes for dynamic conferencing either are computationally unscalable or require communication among users, which is undesirable. The extended symmetric polynomial based dynamic conferencing scheme (ESPDCS) is one such KD scheme which has a high computational complexity that is universe size dependent. In this paper we present an enhancement to the ESPDCS scheme to develop a KD scheme called universe-independent SPDCS (UI-SPDCS) such that its complexity is independent of the universe size. However, the UI-SPDCS scheme does not scale with the conference size. We propose a relatively scalable KD scheme termed as DH-SPDCS that uses the UI-SPDCS scheme and the tree-based group Diffie- Hellman (TGDH) key exchange protocol. The proposed DH-SPDCS scheme provides a configurable trade-off between computation and communication complexity of the scheme.

Red Mud from Brazil: Thermal Behavior and Physical Properties

The main constituents of red mud produced in Aluminio city (S.P., Brazil) are iron, aluminum, and silicon oxides. It has been determined that the average particle diameter for this red mud is between 0.05 and 0.002 mm. It is observed that a decrease in the percentage of smaller particles occurs at temperatures greater than 400 degrees C. This observation corresponds with the thermal analysis and X-ray diffraction (XRD) data, which illustrate the phase transition of goethite to hematite. A 10% mass loss is observed in the thermal analysis patterns due to the hydroxide-oxide phase transitions of iron (primary phase transition) and aluminum (to a lesser extent). The disappearance and appearance of the different phases of iron and aluminum confirms the decomposition reactions proposed by the thermal analysis data. This Brazilian red mud has been classified as mesoporous at all temperatures except between 400 and 500 degrees C where the classification changes to micro/mesoporous.

Bose-Einstein Condensation of Magnons in NiCl2-4SC(NH2)(2)

A Bose-Einstein condensation (BEC) has been observed in magnetic insulators in the last decade. The condensed bosons are magnons associated with an ordered magnetic phase induced by a magnetic field. We review the experiments in the spin-gap compound NiCl2-4SC(NH2)(2), in which the formation of BEC occurs by applying a magnetic field at low temperatures. This is a contribution to the celebration of the 50th anniversary of the Solid State and Low Temperature Laboratory of the University of So Paulo, where this compound was first magnetically characterized.