Avaliação da argila atapulgita para potencial uso como excipiente farmacêutico em formas sólidas

Clays are natural materials that have great potential for use as excipients for solid dosage forms. Palygorskite is a type of clay that has hydrophilic properties as well as a large surface area, which could contribute to the dissolution of drugs. Thus, the present study aims to evaluate the use of palygorskite clay, from Piaui (Northeast region of Brazil), as a pharmaceutical excipient for solid dosage forms, using rifampicin and isoniazid as the model drugs. The former is a poorly soluble drug often associated with isoniazid for tuberculosis treatment. Palygorskite was characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), particle size, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and specific surface area (BET). The rheological and technological properties of palygorskite were determined and compared to those of talc, magnesium stearate and Aersosil 200. Mixtures between drugs and palygorskite were analyzed by differential scanning calorimetry (DSC), thermogravimetric analysis (TG) combined with thermal analysis (DTA) and Fourier Transform Infrared Spectroscopy (FT-IR), where the results were compared with those of the individual compounds. In addition, dissolution studies of solid dispersions and capsules containing the drugs, mixed with either palygorskite or a mixture of talc and magnesium stearate, were performed. The results showed that palygorskite has small particles with a high surface area. Its rheological characteristics were better than those of others commonly used glidants and lubricants. There was no interaction between palygorskite and the drugs (rifampicin and isoniazid). Among the dispersions studied, the mixture with palygorskite (5%) showed the highest drug dissolution when compared to other excipients. The dissolution of the rifampicin capsules containing palygosrkite was faster in higher concentrations. However, these differences were statistically different only in the first minutes of the dissolution experiment. The dissolution profile of isoniazid was also statistically different on the initial part of the experiment. The formulations prepared with isoniazid and palygorskite showed higher drug dissolution, but it was in descending order of concentration. According to these results, the palygorskite clay used in this study has great potential for application as an excipient for solid dosage forms

Produção, acúmulo e decomposição da serrapilhadeira e repartição da precipitação pluviométrica por espécies da caatinga

This study aimed to establish patterns of dynamics of litter and redistribution of rainfall of Caatinga vegetation. Sampling was done monthly for twenty three months in four areas: degraded, successional primary stage, secondary stage and late stage. We installed 72 collectors of 1.0 mx 1.0 m, with nylon fabric background in three areas. Litter deposited was fractionated into leaves, twigs, reproductive structures and miscellaneous, dried and weighed. To assess the stock of accumulated litter we used metal frame with dimensions of 0.5 mx 0.5 m, thrown randomly and collected monthly, taken to the laboratory for oven drying and weighed. To evaluate the decomposition, 40g of litter were placed in nylon bags (litterbags) mesh 1 mm ², dimensions 20.0 x 20.0 cm, being distributed on the soil surface and removed monthly, cleaned, dried and weighed. To evaluate the contribution of rainfall we used interceptometers installed 1.0 m above the ground surface, distributed under the canopy of six species of the caatinga, which evaluated the stemflow through collecting system installed around the stems of these species. The deposition of litter in the primary stage was 2.631,26 kg ha-1; 3.144,89 kg ha-1 in the secondary stage; 3.144,89 kg ha-1 in the late stage. The fraction of leaves was the largest contributor to the formation of litter in three stages. The degraded area showed greater accumulation of litter and decomposition has been sluggish during the dry period. We conclude that occurred greater litterfall in later stages. The late successional stage showed faster decomposition of litter, the evidence that is a better use of litter in nutrient cycling processes and incorporation of organic matter to the soil. The time required to decompose 50 % of the litter in the later stages of succession was lower indicating greater speed of release and reuse of nutrients by the vegetation. The specie jurema preta with less leaf area and consists of leaflets, showed greater internal precipitation in rain events of greater magnitude. The stemflow was not influenced by DAP and basal area. The water lost by trapping represented the largest proportion of total rainfall in all species studied

Crescimento inicial e morfologia foliar em plantas de Enterolobium contortisiliquum (Vell.) Morong. E Erythrina velutina Mart. ex Benth, sob estresse hídrico

The Caatinga is the predominant vegetation type in semi-arid region of Brazil, where many inhabitants depend on hunting and gathering for survival, obtaining resources for: food and feed, folk medicine, timber production, etc. It‟s the dry ecosystem with highest population density in the world. The early stages of development are the most critical during the life cycle of a flowering plant and they‟re primordial to its establishment in environments exposed to water stress. Information about adjustments to the growth of the species, correlated with their studies of distribution in Seridó oriental potiguar, are an important ecological and economic standpoint, because they provide subsidies for the development of cultivation techniques, to programs of sustainable use and recovery of degraded areas. This thesis aimed to study the initial growth and foliar morphology in plants like Enterolobium contortisiliquum (Vell.) Morong. (tamboril) and Erythrina velutina Mart. ex Benth (mulungu), species of occurrence in the Caatinga, under water stress. After sowing and emergency, the seedlings were exposed to three water regimes: 450 (control), 225 (moderate stress) and 112.5 (severe stress) mm of water slide for 40 days. Seeding occurred in bags of 5 kg and after the establishment of seedlings thinning was carried out leaving a plantlet per bag. At the beginning the waterings occurred daily with distilled water, passing to be on alternate days after thinning. Twenty and forty days after the thinning seedlings collections were held to be done analysis of growth and biomass partition. When compared to the control group, the treatments with water stress showed reduction in the growth of the aerial part, growth of the greater root, number of leaves and leaflets, dry leaf area and total phytomass in both species, but in general, this effect was most marked for E. velutina. Regarding the partition of biomass, there were few changes throughout the experiment. Morphological changes in the leaves as a function of stress were not significant, however, there was a trend, in both species, to produce narrower leaves, that facilitate heat loss to the environment. It has not been possible to establish a positive relationship between inhibition of growth and distribution of species, whereas E. velutina is a species of most common occurrence in Seridó oriental potiguar. In this way, other aspects should be taken into account when studying the adaptation of species the dry environments, such as salinity, presence of heavy metals, wind speed, etc

Desenvolvimento de uma metodologia para caracterização de amostras de sedimento: Rio Jundiaí RN

The study of sediment in water bodies presents great environmental importance, because of its ability to adsorb the pollutants, they may facilitate the understanding of the history of the current quality of the water system. Depending on how it is done the collection, analysis can show both a recent contamination as old. The detailed characterization of the sediment may reveal details that can understand how each type of pollutant interacts with the material given its composition. In this work it has developed a systematic methodology to characterize samples of sediment, with the aim to understand how a series of metal is distributed in different size fractions of the sediment. This study was conducted in five samples of sediment (P1, P2, P3a, P3B and P3c) collected in Jundiaí river, one of the most important tributaries of the river Potengi in the region of Macaíba, RN. The characterization was made with the samples previously sieved into meshes with different granulometries (+8#, -8+16#, -16+65# - 65+100#,-100+200#,-200+250# and -250#), using the following techniques: Analysis of specific surface area by BET method, determining the levels of organic matter (OM%) and humidity through the gravimetry and Analysis Thermogravimetric (TG), Infrared Spectroscopy in a Fourier transform (FTIR ), Analysis of X ray diffraction (XRD), analysis of heavy metals by optical emission spectrometry with the Argon Plasma (ICP-OES). The analyzed elements were Al, Cd, Cr, Cu, Fe, Mn, Ni, Zn and P. In addition to the techniques of characterization above, was also made the rebuilding of the samples P1, P2 and P3B in relation to the levels of organic matter and concentration of heavy metals. Then, the results of the recomposed samples were compared with those obtained in crude samples, showing great consistency. The gravimetry, used in determining the levels of organic matter, was not considered an appropriate method because the clay minerals present in the sediment samples analyzed fall apart in the same range of temperature (550-600 0C) used in roasting (600 0C). The results also showed the trend of organic matter and heavy metals to focus on the thin fractions, although the largest concentrations of metals are in intermediate fractions

Influência espaço-temporal e fisiológica na absorção de nutrientes e elementos tóxicos por Eichhornia crassipes visando o uso adequado da sua biomassa: o caso do Rio Apodi/Mossoró - RN

This study aims to determine the amount of nutrients and toxic elements in aquatic macrophytes of species Eichhornia crassipes present in River Apodi/Mossoró - RN and check some of the possibilities of using the biomass produced, based on the influence of space - temporal and physiological absorption of nutrients by plants. For this, was determined: Leaf area, Leaf wet mass, Leaf dry mass, Real humidity, Apparent humidity, Ash, Total nitrogen, Crude protein, Calcium, Magnesium, Potassium, Total phosphorus, Sodium, Iron, Copper, Manganese, Zinc, Nickel, Cobalt, Aluminum, Cadmium, Lead and Total chromium at different times, 2 sampling points and 2 parts of plants (leaves and roots). The results show that the levels of nutrients, protein and toxic elements present in plant tissue of Eichhornia crassipes are influenced by spatial, temporal and physiological variability. In general, because the maximum values in the dry matter for total nitrogen (4.4088 g/100g), crude protein (27.5549 g/100g), total phosphorus (0.642 g/100 g), calcium (1.444 g/100g), magnesium (0.732 g/100 g), potassium (7.51 g/100 g), copper (4.4279 mg/100g), manganese (322.668 mg/100g), sodium (1.39 g/100g), iron (194.169 mg/100g) and zinc (3.5836 mg/100g), there was the possibility of using biomass of Eichhornia crassipes for various purposes such as in food animal, products production for human consumption, organic fertilizers, fabrication of brick low cost, and crafts. For all these applications requires a control of the levels of substances in plant tissue. Based on the levels of nutrients and crude protein, the younger plants (0 Month) would be best to have their biomass used. Moreover, one factor that contributes to the use of larger plants (6 Months), the levels of toxic elements which have significantly small or below the detection limit. Therefore, further studies quantifying the biomass produced/m2 at 0 and 6 months are needed for a more correct choice for the best time of harvest

Síntese e caracterização da peneira molecular MCM-41 contendo terras raras na dessulfurização, utilizando tiofeno como molécula sonda

Mesoporous molecular sieves of MCM-41 type are considered as promising support for metal in the refining processes of petroleum-based materials as catalysts and adsorbents for environmental protection. In this work, mesoporous molecular sieves MCM-41 were modified with different rare earth ions (La, Eu e Yb) for the obtaining nanostrutured materials with catalytic properties. The catalysts were synthesized by the hydrothermal method at 100oC for 120 h, presenting, all the samples, in the gel of synthesis molar ratio Si/Ln = 50. The obtained materials after calcination at 500oC for 2 h were characterized by XRD, surface area BET, TG/DTG, FTIR, and hydrothermal stability at 700ºC. The XRD analysis of the catalysts indicated that the materials containing rare earth presented characteristic hexagonal structure of the mesoporous materials of the type MCM-41. The TG curves showed that the decomposition of the structural template occurs in the materials at temperatures lower than 500oC. The samples presented variations as the specific superficial area, average diameter of pores and thickness of the silica wall, as a function of the nature of the rare earth impregnated in the mesoporous material. Hydrotermal stability was evaluated through the exposition of the materials to water vapour at 700°C. The thiophene adsorptions reach a maximum at 80% of conversion and incorporation of the rare earths showed influence in the process. Adsorption capacity followed the sequence: Yb-MCM-41 < La-MCM-41 < Eu-MCM-41 < MCM-41

Estudo de titanatos nanoestruturados obtidos por tratamento hidrotérmico de óxido de titânio em meio alcalino

TiTanate NanoTubes (TTNT) were synthesized by hydrothermal alkali treatment of TiO2 anatase followed by repeated washings with distinct degrees of proton exchange. TTNT samples with different sodium contents were characterized, as synthesized and after heattreatment (200-800ºC), by X-ray diffraction, scanning and transmission electron microscopy, electron diffraction, thermal analysis, nitrogen adsorption and spectroscopic techniques like FTIR and UV-Vis diffuse reflectance. It was demonstrated that TTNTs consist of trititanate structure with general formula NaxH2−xTi3O7·nH2O, retaining interlayer water in its multiwalled structure. The removal of sodium reduces the amount of water and contracts the interlayer space leading, combined with other factors, to increased specific surface area and mesopore volume. TTNTs are mesoporous materials with two main contributions: pores smaller than 10 nm due to the inner volume of nanotubes and larger pores within 5-60 nm attributed to the interparticles space. Chemical composition and crystal structure of TTNTs do not depend on the average crystal size of the precursor TiO2-anatase, but this parameter affects significantly the morphology and textural properties of the nanostructured product. Such dependence has been rationalized using a dissolution-recrystallization mechanism, which takes into account the dissolution rate of the starting anatase and its influence on the relative rates of growth and curving of intermediate nanosheets. The thermal stability of TTNT is defined by the sodium content and in a lower extent by the crystallinity of the starting anatase. It has been demonstrated that after losing interlayer water within the range 100-200ºC, TTNT transforms, at least partially, into an intermediate hexatitanate NaxH2−xTi6O13 still retaining the nanotubular morphology. Further thermal transformation of the nanostructured tri- and hexatitanates occurs at higher or lower temperature and follows different routes depending on the sodium content in the structure. At high sodium load (water washed samples) they sinter and grow towards bigger crystals of Na2Ti3O7 and Na2Ti6O13 in the form of rods and ribbons. In contrast, protonated TTNTs evolve to nanotubes of TiO2(B), which easily convert to anatase nanorods above 400ºC. Besides hydroxyls and Lewis acidity typical of titanium oxides, TTNTs show a small contribution of protonic acidity capable of coordinating with pyridine at 150ºC, which is lost after calcination and conversion into anatase. The isoeletric point of TTNTs was measured within the range 2.5-4.0, indicating behavior of a weak acid. Despite displaying semiconductor characteristics exhibiting typical absorption in the UV-Vis spectrum with estimated bandgap energy slightly higher than that of its TiO2 precursor, TTNTs showed very low performance in the photocatalytic degradation of cationic and anionic dyes. It was concluded that the basic reason resides in its layered titanate structure, which in comparison with the TiO2 form would be more prone to the so undesired electron-hole pair recombination, thus inhibiting the photooxidation reactions. After calcination of the protonated TTNT into anatase nanorods, the photocatalytic activity improved but not to the same level as that exhibited by its precursor anatase

Síntese e caracterização de membranas zeolíticas tipo mfi e aplicação em separação de aromáticos

The synthesis of MFI-type zeolite membranes was carried by the process in situ or hydrothermal crystallization. We studied the homogenization time of the room temperature and gel filtration just before the crystallization step performed out in an oven, thus obtaining a more uniform zeolite film. The powder synthesized zeolite (structure type MFI, Silicalite) was characterized by several complementary techniques such as Xray diffraction (XRD), scanning electron microscopy (SEM), thermal analysis, temperature programmed desorption (TPD), Fourier Transform infrared spectroscopy (FTIR) and textural analysis by nitrogen adsorption (specific surface area). For the purpose of evaluating the quality of the layer supported on the ceramic support, N2 permeation tests were carried starting from room temperature to 600 °C, where values were observed values more appropriate permeation from 200 °C. With the data obtained, it was made into a graph of temperature versus permeation function, the curve of surface diffusion was found. For scanning electron microscopy, we observed the formation of homogeneous crystals and the zeolite film showed no fissures or cracks, indicating that the process of synthesis and subsequent treatments not damaged the zeolite layer on the support. Carried permeation studies were found values ranging from 3.64x10-6 to 3.78x10-6, 4.71x10-6 to 5.02x10-6, to pressures 20 and 25 psi, respectively. And the mixture xylenes/N2 values were between 5.39x10-6 to 5.67x10-6 and 8.13x10-6 to 8.36x10-6, also for pressures of 20 and 25 psi. The values found for the separation factor were 15.22 at 400 °C in the first experiment and 1.64 for the second experiment at a temperature of 150 °C. It is concluded that the Silicalite membrane was successfully synthesized and that it is effective in the separation of binary mixtures of xylenes

Estudo do desempenho de catalisadores tipo Ni/CexM1-xO2 (M = Zr ou Mn) na reação de oxidação parcial do metano

One of the main applications of methane is in the production of syngas, a mixture of hydrogen and carbon monoxide. Procedures used in this process are steam reforming, CO2 reforming, partial oxidation and autothermal reforming. The present study evaluated and compared the behavior of nickel catalysts supported on mixed oxides of cerium and manganese in the partial oxidation of methane with that of nickel catalysts supported on mixed oxides of cerium and zirconium. Mixed oxides of cerium and zirconium or cerium and manganese were synthesized using two different preparation methods, the polymeric precursor based on Pechini method and combustion reaction using a microwave. This was followed by impregnation with nickel content of 15 %. Samples were calcined at 300, 800 and 900 °C and characterized by specific surface area (SSA), X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM), temperature programmed reduction (TPR) and the reaction of partial oxidation of methane. The specific areas of samples decrease with the rise in calcination temperature and after nickel impregnation. Metal-cerium solid solution was formed and the presence of other manganese species outside the solid solution structure was confirmed in the compound with the highest amounts of manganese oxides showed. With regard to scanning electron microscopy, supports based on cerium and zirconium prepared by Pechini method exhibited agglomerated particles without uniform geometry or visible pores on the surface. However, compounds containing manganese presented empty spaces in its structure. Through synthesis by combustion reaction, morphology acquired independently of the proposed composition demonstrated greater porosity in relation to Pechini synthesis. Although catalysts were prepared using different synthesis methods, the insertion of nickel showed very similar reduction profiles (TPR). In relation to nickel catalysts supported on mixed oxide of cerium and zirconium, there is an initial reduction of NiO species that present certain interaction with the support. This is followed by the reduction of Ce4+ in Ce3+ surface, with subsequent bulk reduction. For catalysts containing manganese, a reduction of nickel oxide species occurs, followed by two stages of reduction for species Mn2O3 in Mn3O4 and Mn3O4 in MnO, with subsequent reduction of bulk. With respect to partial oxidation reactions, the nickel catalyst supported on mixed oxide of cerium and zirconium, prepared using the Pechini method, exhibited CH4 conversion of approximately 80 %, with conversion of 81 % when prepared by combustion. This behavior continued for 10 hours of reaction. Manganese content was also found to directly influence catalytic activity of materials; the greater the manganese oxide content, the faster deactivation and destabilization occurred in the catalyst. In both synthesis methods, the nickel catalyst supported on mixed oxide of cerium and zirconium maintained an H2/CO ratio very close to 2 during the 10 hours of partial oxidation reaction. Samples containing manganese displayed smaller H2/CO ratios and lower performance in partial oxidation.

Síntese e caracterização de ferritas de níquel dopadas com cobalto e efeito da substituição nas suas propriedades magnéticas

The ferrite composition Ni1 - xCoxFe2O4 (0 ≤ x ≤ 0.75) were obtained by the method of microwave assisted synthesis and had their structural and magnetic properties evaluated due to the effect of the substitution of Ni by Co. The compounds were prepared: according to the concept of chemical propellants and heated in the microwave oven with power 7000kw. The synthesized material was characterized by absorption spectroscopy in the infrared (FTIR), Xray diffraction (XRD) using the Rietveld refinement, specific surface area (BET) , scanning electron microscopy (SEM) with aid of energy dispersive analysis (EDS) and magnetic measurements (MAV). The results obtained from these techniques confirmed the feasibility of the method of synthesis employed to obtain the desired spinel structure, the ferrite, nickel ferrite as for nickel doped with cobalt. The results from XRD refinement ally showed the formation of secondary phases concerning stages α - Fe2O3, FeO, (FeCo)O e Ni0. On the other hand, there is an increase in crystallite size with the increase of cobalt in systems, resulting in an increased crystallinity. The results showed that the BET systems showed a reduction in specific surface area with the increase of cobalt and from the SEM, the formation of irregular porous blocks and that the concentration of cobalt decreased the agglomerative state of the system. The magnetic ferrites studied showed different characteristics according to the amount of dopant used, ranging from a very soft magnetic material (easy magnetization and demagnetization ) - for the system without cobalt - a magnetic material with a little stiffer behavior - for systems containing cobalt. The values of the coercive field increased with the increasing growth of cobalt, and the values of saturation magnetization and remanence increased up to x = 0,25 and then reduced. The different magnetic characteristics presented by the systems according to the amount of dopant used, allows the use of these materials as intermediates magnetic

Síntese e caracterização de redes metalorgânicas baseadas em zinco e ácidos benzenodicarboxílicos

Metal Organic Frameworks (MOFs) are supramolecular structures consisted of ions or metal clusters coordinated to organic ligands which are repeated in two or three dimensions. These structures have atracted much attention due to their properties such as low density, high specific surface area and large volume of pores. In this work, MOFs consisted of zinc clusters connected by ditopic ligands, terephthalic acid (1,4- H2BDC) or isophthalic acid (1,3-H2BDC) were synthesized. To obtain the proposed materials, different routes and synthetic parameters were tested, such as the molar ratio of the precursors, the addition of template molecules, the type of solvente, the addition of organic base or the type of a counter-ion of Zn salt. It was found that the variation of these parameters led to the formation of different metalorganic structures. The solids obtained were characterized by XRD, SEM and IR. For the samples identified as MOF- 5, it was verified that the structure was composed of both interpenetrated and non interpenetrated structures. These samples showed a low stability, becoming totally transformed into another structure within less than 72 hours. The addition of the nickel and/or cobalt was found to be a promissing method for increasing the stability of MOF- 5, which in this case, still remained unconverted to another structure even after 15 days of exposure to air. The samples prepared from 1,3-H2BDC were probably new, still unknown Metal Organic Frameworks

Desenvolvimento de catalisadores bifuncionais de óxido de zircônio modificado por óxidos de tungstênio e molibdênio contendo platina para a reação de isomerização de n-parafinas

Bifunctional catalysts based on zircon oxide modified by tungsten (W = 10, 15 and 20 %) and by molybdenum oxide (Mo= 10, 15 e 20 %) containg platinum (Pt = 1%) were prepared by the polymeric precursor method. For comparison, catalysts the tungsten base was also prepared by the impregnation method. After calcinations at 600, 700 and 800 ºC, the catalysts were characterized by X-ray diffraction, fourier-transform infrared spectroscopy, thermogravimetric and differential thermal analysis, nitrogen adsorption and scanning electron microscopy. The profile of metals reduction was determined by temperature programmed reduction. The synthesized catalysts were tested in n-heptane isomerization. X-ray diffractogram of the Pt/WOx-ZrO2 and Pt/MoOx-ZrO2 catalysts revealed the presence of tetragonal ZrO2 and platinum metallic phases in all calcined samples. Diffraction peaks due WO3 and ZrO2 monoclinic also were observed in some samples of the Pt/WOx-ZrO2 catalysts. In the Pt/MoOx-ZrO2 catalysts also were observed diffraction peaks due ZrO2 monoclinic and Zr(MoO4)2 oxide. These phases contained on Pt/WOx-ZrO2 and Pt/MoOx-ZrO2 catalysts varied in accordance with the W or Mo loading and in accordance with the calcination temperature. The infrared spectra showed absorption bands due O-W-O and W=O bonds in the Pt/WOx-ZrO2 catalysts and due O-Mo-O, Mo=O and Mo-O bonds in the Pt/MoOx-ZrO2 catalysts. Specific surface area for Pt/WOx-ZrO2 catalysts varied from 30-160 m2 g-1 and for the Pt/MoOx-ZrO2 catalysts varied from 10-120 m2 g-1. The metals loading (W or Mo) and the calcination temperature influence directly in the specific surface area of the samples. The reduction profile of Pt/WOx-ZrO2 catalysts showed two peaks at lower temperatures, which are attributed to platinum reduction. The reduction of WOx species was evidenced by two reduction peak at high temperatures. In the case of Pt/MoOx-ZrO2 catalysts, the reduction profile showed three reduction events, which are attributed to reduction of MoOx species deposited on the support and in some samples one of the peak is related to the reduction of Zr(MoO4)2 oxide. Pt/WOx-ZrO2 catalysts were active in the n-heptane isomerization with high selectivity to 3-methyl-hexane, 2,3- dimethyl-pentane, 2-methyl-hexane among other branched hydrocarbons. The Pt/MoOx-ZrO2 catalysts practically didn't present activity for the n-heptane isomerization, generating mainly products originating from the catalytic cracking

Dinâmica da paisagem na Microbacia do Riacho Cajazeiras no semiárido potiguar

The semi-arid Northeast region are coming through changes since its formation causing changes in the landscape and increased degradation. The economic dynamics which was established at the Potiguar semiarid had for a long time settled in livestock, subsistence agriculture and cotton, however, these economies decline from the year 1970. Thus, the Potiguar spaces are undergoing by a process of space reordering marked by the growth of agricultural activities and the process of urbanization. In the Potiguar western region these changes weaken significantly transform the landscape. In these areas, the process of urbanization and agricultural activities have caused changes in the hinterland landscape changing the natural dynamics of the caatinga biome that has been subject to negative interference with the indiscriminate removal of vegetation. In this case, the specific study area of the watershed of Cajazeiras Creek located in the cities of Pau dos Ferros, Água Nova, Encanto and Rafael Fernandes, changes in the landscape has led to degradation and environmental fragility. From this perspective, the research objective is to assess the dynamics of the landscape of the watershed of Cajazeiras Creek, semiarid region of the state of Rio Grande do Norte, identifying the degrading factors, the most degraded areas and/or susceptible to degradation and environmental fragility. The research investigated the phenomena of light geosystems theory that emphasizes the integration of elements in shaping the landscape. During this reporting period, it was carried out exploratory and bibliographical research, and geoprocessing techniques to assess the social and environmental conditions of the researched area and its environmental fragility. To do so, first, it was made an multitemporal analisis on the basis of the years 1984, 1996 and 2009 demonstrating that the dynamics of use and land cover in the watershed of Cajazeiras Creek showed a significant change in the landscape, especially in the caatinga vegetation. This has been recovering in various areas of the watershed, especially in its upper course in the mountains of Bom Sera, in Encanto city. The analysis showed the need to develop policies and programs for the maintenance, restoration and preservation of the caatinga vegetation of the river network and of water bodies. In addition, it was identified the most degraded areas of the watershed, environmental fragility and potential emerging that take into account the landscape components such as climate, topography, geology, pedology, geomorphology and the use and occupation of the soil in an integrated manner. The results show that the landscape of the watershed has medium and high environmental fragility throughout its area, especially on the banks of the river network provided by the use and occupation of the soil in an inadequate way with the environmental conditions of the watershed

Desenvolvimento de sistema magnético polimérico contendo antimicrobianos para tratamento de infecções por Helicobacter pylori

Helicobacter pylori is the main cause of gastritis, gastroduodenal ulcer disease and gastric cancer. The most recommended treatment for eradication of this bacteria often leads to side effects and patient poor compliance, which induce treatment failure. Magnetic drug targeting is a very efficient method that overcomes these drawbacks through association of the drug with a magnetic compound. Such approach may allow such systems to be placed slowed down to a specific target area by an external magnetic field. This work reports a study of the synthesis and characterization of polymeric magnetic particles loaded with the currently used antimicrobial agents for the treatment of Helicobacter pylori infections, aiming the production of magnetic drug delivery system by oral route. Optical microscopy, scanning electron microscopy, transmission electron microscopy, x-ray powder diffraction, nitrogen adsorption/desorption isotherms and vibrating sample magnetometry revealed that the magnetite particles, produced by the co-precipitation method, consisted of a large number of aggregated nanometer-size crystallites (about 6 nm), creating superparamagnetic micrometer with high magnetic susceptibility particles with an average diameter of 6.8 ± 0.2 μm. Also, the polymeric magnetic particles produced by spray drying had a core-shell structure based on magnetite microparticles, amoxicillin and clarithromycin and coated with Eudragit® S100. The system presented an average diameter of 14.2 ± 0.2 μm. The amount of magnetite present in the system may be tailored by suitably controlling the suspension used to feed the spray dryer. In the present work it was 2.9% (w/w). The magnetic system produced may prove to be very promising for eradication of Helicobacter pylori infections