Estudo da influência da morfologia de nanopartículas de sílica mesoporosa na liberação do anticancerígeno indol-3-carbinol

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Ceilândia, Programa de Pós-graduação em Ciências e Tecnologias em Saúde, 2015.

Bioprospecção de polissacarídeos sulfatados de macroalgas marinhas do litoral do Rio Grande do Norte: caracterização de uma heterofucana extraída da alga marron Sargassum filipendula que induz apoptose em células HeLa

The coast of Rio Grande do Norte has more than 100 species of seaweed, mostly unexplored regarding their pharmacological potential. The sulfated polysaccharides (PS) are by far the more seaweed compounds studied, these present a range of biological properties, such as anticoagulant activity, anti-inflammatory, antitumor and antioxidant properties. In this study, we extract sulfated polysaccharide rich-extracts of eleven algae from the coast of Rio Grande do Norte (Dictyota cervicornis; Dictiopterys delicatula; Dictyota menstruallis; Dictyota mertensis; Sargassum filipendula; Spatoglossum schröederi; Gracilaria caudata; Caulerpa cupresoides; Caulerpa prolifera; Caulerpa sertularioides e Codim isthmocladum), and these were evaluated for the potential anticoagulant, antioxidant and antiproliferative. All polysaccharide extracts showed activity for anticoagulant, antioxidant and/or antiproliferative activity, especially D. delicatula and S. filipendula, which showed the most prominent pharmacological potential, thereby being chosen to have their sulfated polysaccharides extracted. By fractionating method were obtained six fractions rich in sulfated polysaccharides to the algae D. delicatula (DD-0,5V, DD-0, 7V, DD-1,0v, DD-1,3v, DD-1,5v and DD-2,0) and five fractions to the alga S. filipendula (SF-0,5V, SF-0,7V, SF-1,0v, SF-1,5v and SF-2,0v). For the anticoagulant assay only the fractions of D. delicatula showed activity, with emphasis on DD-1, 5v that presented the most prominent activity, with APTT ratio similar to clexane® at 0.1 mg/mL. When evaluated the antioxidant potential, all fractions showed potential in all tests (total antioxidant capacity, hydroxyl and superoxide radicals scavenging, ferrous chelation and reducing power), however, the ability to chelate iron ions appears as the main mechanism antioxidant of sulfated polysaccharides from seaweed. In antiproliferative assay, all heterofucanas showed dose-dependent activity for the inhibition of cell proliferation of HeLa, however, with the exception of SF-0,7V, SF- 1,0v and SF-1,5v, all fractions showed antiproliferative activity against MC3T3, a normal cell line. The heterofucana SF-1,5V had its antiproliferative mechanism of action evaluated. This heterofucan induces apoptosis in HeLa cells by a pathway caspase independent, promoting the release of apoptosis Inducing Factor (AIF) in the cytosol, which in turn induces chromatin condensation and DNA fragmentation into 50Kb fragments. These results are significant in that they provide a mechanistic framework for further exploring the use of SF-1.5v as a novel chemotherapeutics against human cervical cancer.

Purificação, caracterização e efeitos imunomodulatório e antiproliferativo de uma lectina do fungo Clavaria cristata (Holmsk.) Pers

A 140,0 kDa lectin was purified and characterized from the mushroom Clavaria cristata. The purification procedures from the crude extract of the mushroom comprised gel filtration chromatography on Sephacryl s200 and ion exchange on Resource Q column. The purified lectin agglutinated all types of human erythrocytes with preference for trypsinized type O erythrocytes. The haemagglutinating activity is dependent of Ca 2+ ions and was strongly inhibited by the glycoprotein bovine submaxillary mucin (BSM) up to the concentration of 0, 125 mg/mL. The C. cristata lectin (CcL) was stable in the pH range of 2,5-11,5 and termostable up to 80 °C. CcL molecular mass determined by gel filtration on a Superose 6 10 300 column was approximately 140,3 kDa. SDS polyacrilamide gel electrophoresis revealed a single band with a molecular mass of approximately 14,5 kDa, when the lectin was heated at 100 ⁰C in the presence or absence of β-mercaptoethanol. CcL induced activation of murine peritoneal macrophages in vitro resulting in the release of nitric oxide (NO), reaching the maximum production at 24 h. In experimental paw oedema model in mice, CcL showed proinflammatory activity being able to induce oedema formation. Cell viability of HepG2, MDA 435 e 3T3 cell lines was examined after 72 h of incubation with CcL in different concentrations (0,5-50 μg/mL). CcL inhibited HepG2 cells growth with an IC50 value of 50 μg/mL. In the present work, the observed immunomodulatory and antiproliferative effects indicate CcL as a possible immunomodulator compound, interfering in the macrophages immune response, taking possible anti-parasitic, anti-tumoral effects or diagnostic and/or therapeutic

Interaction of ions, electrons, and laser pulses with surfaces

133 p.

Nanopartículas de alginato como sistema de liberação para o herbicida clomazone

In this paper, we describe the preparation of alginate nanoparticles as a delivery system for the herbicide clomazone. Two different methods were investigated and characterized by size distribution, zeta potencial, pH and in vitro release. The alginate/AOT nanoparticles had higher rates of association of the herbicide clomazone than alginate/chitosan nanoparticles. Clomazone release profile, showed a significant difference in release behavior of pure herbicide in solution when compared with herbicide loaded in both alginate nanoparticles. This study is important to construct a biodegradable release system using herbicide for later release into more specific targets, avoiding contamination of environmental matrices.

Sequestering of Fe and Pb ions from Wastewater by Canarium schweinfurthii after carbonization and chemical treatment: Isothermal and Kinetic Modeling

In this paper agricultural waste; Canarium schweinfurthii was explored for the sequestering of Fe and Pb ions from wastewater solution after carbonization and chemical treatment at 400oC. Optimum time of 30 and 150 min with percentage removal of 95 and 98% at optimum pH of 2 and 6 was obtained for Fe and Pb ions. Kinetics model followed pseudofirst order as sum of absolute error (EABS) between Qe and Qc greater than that of pseudo second order. Parameters evaluated from isothermal equation (Freundlich and Langmuir) showed that KL and QO for Fe > Pb and R2 for Langmuir> Freundlich. The study reveals the suitability of the adsorbent for sequestering of Fe and Pb ions from industrial wastewater.

Equilibrium Sorption Studies of Hg (II) Ions from Aqueous Solution using Powdered Swamp Arum ( Lasimorpha senegalensis ) Seeds.

The potential of swamp arum ( Lasimorpha senegalensis ) seeds as a low-cost adsorbent for the removal of Hg (II) ions from aqueous solution was investigated in this study. The influence of initial metal concentration on the percent adsorption of Hg (II) ions onto powdered swamp arum seeds was studied in a batch system and the filtrate was analyzed using Atomic Absorption Spectrometry (AAS). The percent adsorbed for 10, 20, 40, 60 and 80 mg/L of the aqueous solution were 97.7, 98.9, 99.3, 99.7, and 96.5% respectively. Three isotherms; Langmuir, Freundlich, and BET were used to model the equilibrium sorption of Hg (II) ions onto powdered swamp arum seeds, with a correlation coefficient of 0.998, 0.784 and0.842 respectively. The Langmuir model fitted the equilibrium data best, with a correlation coefficient of 0.998 and a maximum adsorption capacity qm, of 5.917 mg/g. Thus, indicating monolayer coverage on the adsorbent. The results showed that swamp arum seed have the potential to be applied as alternative lowcost biosorbent in the remediation of heavy metal contamination in waste water.

A Staggered Decameric Assembly of Human C-Reactive Protein Stabilized by Zinc Ions Revealed by X-ray Crystallography

International audience

Engineering a Quantum Many-body Hamiltonian with Trapped Ions

While fault-tolerant quantum computation might still be years away, analog quantum simulators offer a way to leverage current quantum technologies to study classically intractable quantum systems. Cutting edge quantum simulators such as those utilizing ultracold atoms are beginning to study physics which surpass what is classically tractable. As the system sizes of these quantum simulators increase, there are also concurrent gains in the complexity and types of Hamiltonians which can be simulated. In this work, I describe advances toward the realization of an adaptable, tunable quantum simulator capable of surpassing classical computation. We simulate long-ranged Ising and XY spin models which can have global arbitrary transverse and longitudinal fields in addition to individual transverse fields using a linear chain of up to 24 Yb+ 171 ions confined in a linear rf Paul trap. Each qubit is encoded in the ground state hyperfine levels of an ion. Spin-spin interactions are engineered by the application of spin-dependent forces from laser fields, coupling spin to motion. Each spin can be read independently using state-dependent fluorescence. The results here add yet more tools to an ever growing quantum simulation toolbox. One of many challenges has been the coherent manipulation of individual qubits. By using a surprisingly large fourth-order Stark shifts in a clock-state qubit, we demonstrate an ability to individually manipulate spins and apply independent Hamiltonian terms, greatly increasing the range of quantum simulations which can be implemented. As quantum systems grow beyond the capability of classical numerics, a constant question is how to verify a quantum simulation. Here, I present measurements which may provide useful metrics for large system sizes and demonstrate them in a system of up to 24 ions during a classically intractable simulation. The observed values are consistent with extremely large entangled states, as much as ~95% of the system entangled. Finally, we use many of these techniques in order to generate a spin Hamiltonian which fails to thermalize during experimental time scales due to a meta-stable state which is often called prethermal. The observed prethermal state is a new form of prethermalization which arises due to long-range interactions and open boundary conditions, even in the thermodynamic limit. This prethermalization is observed in a system of up to 22 spins. We expect that system sizes can be extended up to 30 spins with only minor upgrades to the current apparatus. These results emphasize that as the technology improves, the techniques and tools developed here can potentially be used to perform simulations which will surpass the capability of even the most sophisticated classical techniques, enabling the study of a whole new regime of quantum many-body physics.

MANIPULATION OF IONS, ELECTRONS, AND PHOTONS IN 2D MATERIALS BY ION INTERCALATION

2D materials have attracted tremendous attention due to their unique physical and chemical properties since the discovery of graphene. Despite these intrinsic properties, various modification methods have been applied to 2D materials that yield even more exciting results. Among all modification methods, the intercalation of 2D materials provides the highest possible doping and/or phase change to the pristine 2D materials. This doping effect highly modifies 2D materials, with extraordinary electrical transport as well as optical, thermal, magnetic, and catalytic properties, which are advantageous for optoelectronics, superconductors, thermoelectronics, catalysis and energy storage applications. To study the property changes of 2D materials, we designed and built a planar nanobattery that allows electrochemical ion intercalation in 2D materials. More importantly, this planar nanobattery enables characterization of electrical, optical and structural properties of 2D materials in situ and real time upon ion intercalation. With this device, we successfully intercalated Li-ions into few layer graphene (FLG) and ultrathin graphite, heavily dopes the graphene to 0.6 x 10^15 /cm2, which simultaneously increased its conductivity and transmittance in the visible range. The intercalated LiC6 single crystallite achieved extraordinary optoelectronic properties, in which an eight-layered Li intercalated FLG achieved transmittance of 91.7% (at 550 nm) and sheet resistance of 3 ohm/sq. We extend the research to obtain scalable, printable graphene based transparent conductors with ion intercalation. Surfactant free, printed reduced graphene oxide transparent conductor thin film with Na-ion intercalation is obtained with transmittance of 79% and sheet resistance of 300 ohm/sq (at 550 nm). The figure of merit is calculated as the best pure rGO based transparent conductors. We further improved the tunability of the reduced graphene oxide film by using two layers of CNT films to sandwich it. The tunable range of rGO film is demonstrated from 0.9 um to 10 um in wavelength. Other ions such as K-ion is also studied of its intercalation chemistry and optical properties in graphitic materials. We also used the in situ characterization tools to understand the fundamental properties and improve the performance of battery electrode materials. We investigated the Na-ion interaction with rGO by in situ Transmission electron microscopy (TEM). For the first time, we observed reversible Na metal cluster (with diameter larger than 10 nm) deposition on rGO surface, which we evidenced with atom-resolved HRTEM image of Na metal and electron diffraction pattern. This discovery leads to a porous reduced graphene oxide sodium ion battery anode with record high reversible specific capacity around 450 mAh/g at 25mA/g, a high rate performance of 200 mAh/g at 250 mA/g, and stable cycling performance up to 750 cycles. In addition, direct observation of irreversible formation of Na2O on rGO unveils the origin of commonly observed low 1st Columbic Efficiency of rGO containing electrodes. Another example for in situ characterization for battery electrode is using the planar nanobattery for 2D MoS2 crystallite. Planar nanobattery allows the intrinsic electrical conductivity measurement with single crystalline 2D battery electrode upon ion intercalation and deintercalation process, which is lacking in conventional battery characterization techniques. We discovered that with a “rapid-charging” process at the first cycle, the lithiated MoS2 undergoes a drastic resistance decrease, which in a regular lithiation process, the resistance always increases after lithiation at its final stage. This discovery leads to a 2- fold increase in specific capacity with with rapid first lithiated MoS2 composite electrode material, compare with the regular first lithiated MoS2 composite electrode material, at current density of 250 mA/g.

Síntese e caracterização do poli(ácido láctico) para potencial uso em sistemas de liberação controlada de fármacos

With the advances in medicine, life expectancy of the world population has grown considerably in recent decades. Studies have been performed in order to maintain the quality of life through the development of new drugs and new surgical procedures. Biomaterials is an example of the researches to improve quality of life, and its use goes from the reconstruction of tissues and organs affected by diseases or other types of failure, to use in drug delivery system able to prolong the drug in the body and increase its bioavailability. Biopolymers are a class of biomaterials widely targeted by researchers since they have ideal properties for biomedical applications, such as high biocompatibility and biodegradability. Poly (lactic acid) (PLA) is a biopolymer used as a biomaterial and its monomer, lactic acid, is eliminated by the Krebs Cycle (citric acid cycle). It is possible to synthesize PLA through various synthesis routes, however, the direct polycondensation is cheaper due the use of few steps of polymerization. In this work we used experimental design (DOE) to produce PLAs with different molecular weight from the direct polycondensation of lactic acid, with characteristics suitable for use in drug delivery system (DDS). Through the experimental design it was noted that the time of esterification, in the direct polycondensation, is the most important stage to obtain a higher molecular weight. The Fourier Transform Infrared (FTIR) spectrograms obtained were equivalent to the PLAs available in the literature. Results of Differential Scanning Calorimetry (DSC) showed that all PLAs produced are semicrystalline with glass transition temperatures (Tgs) ranging between 36 - 48 °C, and melting temperatures (Tm) ranging from 117 to 130 °C. The PLAs molecular weight characterized from Size Exclusion Chromatography (SEC), varied from 1000 to 11,000 g/mol. PLAs obtained showed a fibrous morphology characterized by Scanning Electron Microscopy (SEM)

Copper ions binding in cu‐alginate gelation

Alginate polysaccharide forms viscous aqueous dispersions and has the ability to form gels in the presence of divalent cations such as calcium and copper. In this work, we have studied cooper ions binding during Cu‐alginate gelation, obtaining quantitative information about the amount and kinetics of cation binding. Our results indicate that copper binding during gelation occurs until a Langmuir‐type equilibrium is reached between bound and free ions in the gel‐contacting solution. The kinetics of metal ions binding can be modeled using Ritchie equation–derived models, allowing the prediction of ionic binding and gel formation temporal evolution. The ratio between cationic and polysaccharide quantities in the gelation system determines the kinetics of gelation and the characteristics of the gel formed. The experimental results and models applied in the work give more insights on alginate gelation and contribute to a reliable design and control of production methods for alginate gel structures.

Decomposição e liberação de nutrientes por espécies de leguminosas utilizadas como adubo verde no agropólo Jaguaribe-Apodi, CE.

2016

Decomposição e liberação de nutrientes de resíduos culturais em áreas de plantio de soja (Glycine max) sob plantio direto no Cerrado Goiano.

A avaliação da decomposição dos resíduos vegetais adicionados ao solo pelas plantas de cobertura permite uma melhor compreensão do fornecimento de nutrientes para as culturas de interesse comercial. O objetivo do trabalho foi avaliar a taxas de decomposição e a dinâmica da liberação de N de resíduos culturais na entre safra da Soja sob plantio direto. Os resíduos utilizados foram a braquiária (Brachiaria sp.) e sorgo (Sorghum bicolor L. Moench). A produção média de biomassa de braquiária foi de 6,1 Mg ha-1 e de 3,8 Mg ha-1 no tratamento com sorgo. A decomposição da matéria seca e a liberação de nutrientes foram monitoradas por meio de coletas dos resíduos contidos em sacolas de decomposição, realizadas 15, 30, 60, 90, 120 dias após a adição das sacolas de decomposição nas áreas de estudo. Os T1/2 da massa seca remanescente diferiram estatisticamente entre os sistemas avaliados. A braquiária apresentou menores valores de meia vida quando comparados ao sorgo. Este comportamento pode ser atribuído provavelmente, às grandes quantidades de biomassa acumulada pela braquiária, favorecendo maiores teores de umidade no solo, e uma menor relação C/N da braquiária quando comparada ao sorgo.

Effect of residual vanadyl ions on the spectroscopic analysis of humic acids: a multivariate approach.

In a study of the vanadyl (VO2þ)-humic acids system, the residual vanadyl ion suppressed fluorescence and specific electron paramagnetic resonance (EPR) and NMR signals. In the case of NMR, the proton rotating frame relaxation times (T1qH) indicate that this suppression is due to an inefficient H-C cross polarization, which is a consequence of a shortening of T1qH. Principal components analysis (PCA) facilitated the isolation of the effect of the VO2þ ion and indicated that the organic free radical signal was due to at least two paramagnetic centres and that the VO2þ ion preferentially suppressed the species whose electronic density is delocalized over O atoms (greater g-factor). additionally, the newly obtained variables (principal components ? PC) indicated that, as the result of the more intense tillage a relative increase occurred in the accumulation of: (i) recalcitrant structures; (ii) lignin and long-chain alkyl structures; and (iii) organic free radicals with smaller g-factors.