Entrapment Process Research Articles

過剰アルゴン：輸送・捕獲過程

過剰アルゴン：輸送・捕獲過程

Network Modeling of EOR Processes: A Combined Invasion Percolation and Dynamic Model for Mobilization of Trapped Oil

A novel concept for modeling pore-scale phenomena included in several enhanced oil recovery (EOR) methods is presented. The approach combines a quasi-static invasion percolation model with a single-phase dynamic transport model in order to integrate mechanistic chemical oil mobilization methods. A framework is proposed that incorporates mobilization of capillary trapped oil. We show how double displacement of reservoir fluids can contribute to mobilize oil that are capillary trapped after waterflooding. In particular, we elaborate how the physics of colloidal dispersion gels (CDG) or linked polymer solutions (LPS) is implemented. The linked polymer solutions consist of low concentration partially hydrolyzed polyacrylamide polymer crosslinked with aluminum citrate. Laboratory core floods have shown demonstrated increased oil recovery by injection of linked polymer solution systems. LPS consist of roughly spherical particles with sizes in the nanometer range (50–150 nm). The LPS process involve mechanisms such as change in rheological properties effect, adsorption and entrapment processes that can lead to a microscopic diversion and mobilization of waterflood trapped oil. The purpose is to model the physical processes occurring on pore scale during injection of linked polymer solutions. A sensitivity study has also been performed on trapped oil saturation with respect to wettability status to analyze the efficiency of LPS on different wettability conditions. The network modeling results suggest that weakly wet reservoirs are more suitable candidates for performing linked polymer solution injection.

Physicochemical characterisation and biological evaluation of polyvinylpyrrolidone-iodine engineered polyurethane (Tecoflex®)

Bacterial adhesion and encrustation are the known causes for obstruction or blockage of urethral catheters and ureteral stents, which often hinders their effective use within the urinary tract. In this in vitro study, polyvinylpyrrolidone-iodine (PVP-I) complex modified polyurethane (Tecoflex(®)) systems were created by physically entrapping the modifying species during the reversible swelling of the polymer surface region. The presence of the PVP-I molecules on this surfaces were verified by ATR-FTIR, AFM and SEM-EDAX analysis, while wettability of the films was investigated by water contact angle measurements. The modified surfaces were investigated for its suitability as a urinary tract biomaterial by comparing its lubricity and ability to resist bacterial adherence and encrustation with that of base polyurethane. The PVP-I modified polyurethane showed a nanopatterned surface topography and was highly hydrophilic and more lubricious than control polyurethane. Adherence of both the gram positive Staphylococcus aureus (by 86%; **P < 0.01) and gram-negative Pseudomonas aeruginosa (by 80%; *P < 0.05) was significantly reduced on the modified surfaces. The deposition of struvite and hydroxyapatite the major components of urinary tract encrustations were significantly less on PVP-I modified polyurethane as compared to base polyurethane, especially reduction in hydroxyapatite encrustation was particularly marked. These results demonstrated that the PVP-I entrapment process can be applied on polyurethane in order to reduce/lower complications associated with bacterial adhesion and deposition of encrustation on polyurethanes.

Impact of alginate type and bead diameter on mass transfers and the metabolic activities of encapsulated C3A cells in bioartificial liver applications

Liver-assist devices have been developed in the last few decades to support patients with liver failure on the road to recovery or transplantation. Fluidised bed bio-artificial livers--where liver cells are encapsulated within alginate beads--appear to be a valuable alternative to hollow fibre devices for improving mass transfers and enhancing treatment efficacy. This approach nevertheless deserves optimization in terms of bead production. The aim of this study was to investigate the impact of alginate type and of two bead diameters (1000 µm and 600 µm) on mass transfers within beads and on the biological functions of encapsulated C3A cells. After assessing the effect of the encapsulation process on bead quality, we investigated cell viability and metabolic activities (ammonia, albumin, alpha-fetoprotein synthesis and glucose consumption). They were successfully maintained over 48 h within fluidised bed bioreactors, independently of alginate type and bead diameter. Mass transfers were not significantly influenced by the latter parameters. Finally, suggestions are made for improving the entrapment process as a means of enhancing the treatment efficiency of the fluidised bed bioartificial liver.

Lattice Boltzmann study of bubble entrapment during droplet impact

AbstractThe entrapment ofbubbleduring droplet impact on solid surfaces was studied by using a phase‐field lattice Boltzmann model (LBM). Numerous three‐dimensional simulations were performed and several types of entrapment were found under specific impact conditions. Some cases are similar to previous studies, whereas others are reported for the first time. Dissections of the entrapment processes were carried out, and detailed analyses of the flow fields and interface motions were provided at selected moments for certain cases. The effects of the Reynolds number, the Weber number and the surface wettability were analyzed based on the observation. Besides, some computational issues of phase‐field simulations were discussed for the present problem. Finally, the impact condition to prevent entrapment was preliminarily estimated in terms of the Ohnesorge number upon examination of numerous simulations. Copyright © 2009 John Wiley &amp; Sons, Ltd.

Resultados preliminares del estudio zooarqueológico y tafonómico de los restos óseos de roedores del sitio Calera (Sierras Bayas, partido de Olavarría, provincia de Buenos Aires)

The Calera site, located in the Sierras Bayas (Olavarria, Buenos Aires province), consists of a number of features (called pits) with variable dimensions that contained a large quantity of archaeological material. The analysis performed to date indicates a cultural origin of both features and material remains, which may be the product of ritual offerings and/or ceremonial garbage generated during periods of hunter-gatherer band groupings in the Late Holocene (ca. 3400 and 1750 years BP). In this article, the taphonomic and zooarchaeological analysis of the rodent mandibles and skulls from pit No. 2 is presented. The results suggest that these faunistic remains were originated by different processes and agents, both natural and human, and were incorporated into the pit by different mechanisms such as natural entrapment, cultural deposition and secondary processes, such as eolic and/or fluvial transport.

Silver coated vapor-grown-carbon nanofibers for effective reinforcement of polypropylene–polyaniline

This work utilizes a modification of our process of polymer entrapment in silver to deposit silver crystals on carbon nanofibers at different relative concentrations. The experimental procedure and the characteristics of silver coated nanofibers are presented in detail. The resulting nanofibers are then melt-mixed with a polypropylene–polyaniline blend to form a uniform dispersion that is finally extruded to produce continuous monofilament composites of high axial orientation. The reinforcement effect of the silver coated nanofibers, manifested in the mechanical properties of the monofilament composites, is 3–5 folds higher than that of the pristine nanofibers due to the improved stress transfer mechanism of the former. Additional attractive properties of the new system may result from its anisotropic crystalline structure, enhanced thermal stability, potential electrical conductivity and antibacterial behavior.

Entrapment of Heteropolyacids in Metallic Silver Matrices: Unique Heterogenized Acid Catalysts

AbstractThe general method of doping metals with organic, bio‐organic, and polymeric dopants is extended to inorganic dopants. Specifically, the heteropolyacids H3[P(M3O10)4] (PMA; M=Mo, W) were successfully entrapped within a metallic silver matrix. The obtained PMA@Ag composites were fully characterized by PXRD, surface area, SEM, TEM and EDX measurements, showing a homogenous distribution of the catalyst in the support. The new composite materials are successfully applied in the catalytic alkylation of arenes, as demonstrated by the successful adamantylation of toluene or anisole with 1‐bromoadamantane. Furthermore, this reaction is applied with the less reactive 1‐chloroadamantane in both the supported and unsupported case. PMoA, which easily decomposes under the applied reaction conditions, is protected by entrapment and shows increased activity when supported in the silver matrix. In the same reaction, the entrapped PWA shows a drastically increased reaction rate compared to the free acid, which further confirms the positive synergistic effects of the entrapment process. Both heterogenized catalysts are successfully recycled and reused, but the reaction time steadily increases in successive cycles due to agglomeration of the catalyst, which results in a lower accessibility of the dopant. Moreover, the alkylation can be extended to other alkyl chloride substrates, as demonstrated for tert‐butyl chloride.

Rational design, fabrication, characterization and in vitro testing of biodegradable microparticles that generate targeted and sustained transgene expression in HepG2 liver cells

Poly(lactide-co-glycolide) (PLGA) microparticles have significant potential for sustained delivery of plasmid DNA (pDNA). However, unmodified PLGA microparticles have poor transfection efficiencies. In this study, we use several approaches to enhance the transfection efficiencies of PLGA microparticles in a HepG2 liver cell line. Polyethylenimine (PEI) is used to condense the pDNA prior to loading into the PLGA microparticles. This provides enhanced loading efficiencies and greater protection to the pDNA during the entrapment process. In addition, the pDNA used (ApoE) incorporates a hybrid liver-specific murine albumin enhancer/α1 antitrypsin promoter (AlbE/hAAT) to enhance transgene expression in human liver (HepG2) cells. The percentage of surfactant used in the preparation of the microparticles, the polymer composition of the PLGA, the ratio of the PEI to pDNA (N/P), the structure of the PEI and the potential utility of a galactose targeting ligand were then investigated to further optimize the efficacy of the cationic microparticle non-viral delivery system in transfecting HepG2 cells. For each PLGA PEI-pDNA microparticle formulation prepared, we evaluated particle size, ζ-potential, loading of pDNA, cytotoxicity, and transgene expression in HepG2 cells and control human embryonic kidney (HEK293) and monkey African green kidney fibroblast-like (COS7) cells. Loading PLGA particles with PEI-ApoE pDNA complexes resulted in a significant reduction in particle size when compared to PLGA microparticles loaded with ApoE pDNA alone. Scanning electron microscopy images showed that all the particle formulations were smooth and spherical in appearance. Incorporation of the cationic PEI in the PLGA particles changed the ζ-potential from negative to positive. Complexing PEI with ApoE pDNA increased the loading efficiency of the ApoE pDNA into the PLGA microparticles. The cytotoxicity of PLGA particles loaded with PEI-ApoE pDNA complexes was similar to PLGA particles loaded with ApoE pDNA alone. The transfection efficiency of all particle formulations prepared with ApoE pDNA was significantly higher in HepG2 cells when compared to HEK293 and COS7 cell lines. The release of PEI-pDNA complexes from particles prepared with different PLGA polymer compositions including PLGA 50–50, PLGA 75–25, and PLGA 85–15 was sustained in all cases but the release profile was dependent on the polymer composition. Transmission electron microscopy images showed that PEI-pDNA complexes remained structurally intact after release. The optimum formulation for PLGA particles loaded with PEI-ApoE pDNA complexes was prepared using 2% polyvinyl alcohol, 50–50 PLGA compositions and N/P ratios of 5–10. Strong sustained transgene expression in HepG2 cells was generated by PLGA PEI-ApoE pDNA particles up to the full 13 days tested.

Migration and entrapment of mercury in porous media

Elemental mercury is an immiscible liquid with high density and high interfacial tension with water. Its movement in the saturated subsurface region is therefore considered as a case of two phase flow involving mercury and water and is expected to be governed by gravity, viscous, hydrodynamic and capillary forces. This paper investigates the migration and capillary entrapment of mercury in the subsurface based on controlled laboratory capillary pressure–saturation experiments. In the first place, entrapment of mercury was observed in homogeneous porous media. Residual mercury saturation and van Genuchten's parameters for mercury entrapment were generated. These data will provide vital inputs for mercury migration and entrapment models. Secondly, the dependency of residual saturation on fluid properties was brought out in this work by comparing the experimental results of mercury–water system and DNAPL–water systems. Capillary forces were large enough in mercury–water systems to counteract the high gravity forces and caused the entrapment of mercury. Large density differences between mercury and water lead to a high Bond number and thus a low residual mercury saturation was obtained which corroborates with existing DNAPL theories. However, the inverse relationship between residual saturation and capillary number established for NAPL–water systems cannot be compared with mercury–water systems. Moreover, the critical capillary numbers and Bond numbers to mobilize DNAPLs may not be applicable to mercury since mercury has a low capillary number and high Bond number. This work has enabled the understanding of the process of migration and entrapment of mercury and provided useful inputs for two phase flow models specific to mercury–water systems. It has also highlighted the influence of fluid properties on entrapment and mobilization particularly for highly dense, viscous fluid which also possesses high interfacial tension with water.

Surface Engineering of Polycaprolactone by Biomacromolecules and their Blood Compatibility

Improving blood compatibility of biodegradable polymers is an area of intensive research in blood contacting devices. In this study, curdlan sulphate and heparin-modified poly (caprolactone) (PCL) hybrids were developed by physically entrapping these molecules on the PCL surface. This modification technique was performed by reversible gelation of the PCL surface region following exposure to a solvent and nonsolvent mixture. The presence of these biomacromolecules on the PCL surface was verified by atomic force microscopy (AFM) and scanning electron microscopy and energy dispersive X-ray analysis (SEM-EDAX) analysis, while wettability of the films was investigated by dynamic contact angle measurements. The blood compatibilities of the surface-modified films were examined using in vitro platelet and leukocyte adhesion and thrombus formation. Mouse RAW 264.7 macrophage cells were used to assess the cell adhesion and inflammatory response to the modified surface by quantifying mRNA expression levels of proinflammatory cytokines namely TNF-α and IL-1β using real-time polymerase chain reaction (RT-PCR). A lower platelet and leukocyte adhesion and activation was observed on the modified films incubated with whole human blood for 2 h. The thrombus formation on the PCL was significantly decreased upon immobilization of both curdlan sulphate (39%, *p<0.05) and heparin (28%, *p<0.01) when compared to bare PCL (80%). All of these results revealed that improved blood compatibility was obtained by surface entrapment of both curdlan sulphate (CURS) and heparin (HEP) onto PCL films. Both PCL-CURS and PCL-HEP films reduced RAW 264.7 macrophage cell adhesion (*p<0.05) with respect to the base unmodified PCL. The cellular inflammatory response was suppressed on the modified substrates. The mRNA expression levels of proinflammmatory cytokines (TNF-α and IL-1β) were upregulated on bare PCL, while it was significantly lower on PCL-CURS and PCL-HEP substrates (**p<0.001). Thus, this biomacromolecule entrapment process can be applied on PCL in order to achieve improved blood compatibility and reduced inflammatory host response for its future blood contacting applications.

Differential Hydrocarbon Migration and Entrapment in the Karstified Carbonate Reservoir: A Case Study of the Well TZ83 Block of the Central Tarim Uplift Zone

The hydrocarbon migration and entrapment mechanism in the lower overlapped basins, occurring in the complex carbonate pore-fissure-fracture reservoirs, is one of the key problems that have to be solved for effective hydrocarbon exploration. The production, gas/oil ratio, and the composition of crude oils and natural gas in the TZ83 Well block are high at the intersection point of the NE and NW-strike faults and decrease gradually along the ridge of the structure. A basic model of the pore-fissure-fracture system is built according to the achievements in the research on carbonate karstification. Processes of hydrocarbon migration and entrapment in this system are analyzed, which indicate that an understanding of the complexness of differential hydrocarbon migration is the key to interpreting this phenomenon. The hydrocarbon must charge the nearest compartment before migrating further away to charge other compartments in its pathway in the complex pore-fissure-fracture system. As a result, the following two phenomena appear: (1) Gas is enriched near the hydrocarbon injection point and drives away the oil, which is enriched in the compartments farther from the injection point. (2) The complex gas–oil–water relationship is controlled by the lateral connecting networks. Based on this, this article shows that the fault intersection point is the injection point of the oil and gas, and the main pathway system is distributed along the ridge of the structure. The theory of deferential hydrocarbon migration in the pore-fissure-fracture system can be presented from two aspects: (1) In hydrocarbon exploration, the structure of the fissure-fracture system should be described first, and then the special distribution of gas–oil–water can be predicted according to the main charging point and the main pathway system. (2) Exploration should be confined to the hydrocarbon charging point and the main pathway systems. An explored area should not be abandoned merely due to failures in some wells.

The biocompatibility of sulfobetaine engineered polymethylmethacrylate by surface entrapment technique

Sulfobetaine-modified polymethylmethacrylate (PMMA) systems were created by physically entrapping the zwitterionic species on the PMMA surface. The presence of the sulfobetaine molecules on these surfaces were verified by ATR-FTIR and SEM-EDAX analysis, while wettability of the films was investigated by dynamic contact angle measurements. The short-term (4 h) adhesion of two bacterial species (gram-positive Staphylococcus aureus and gram-negative Pseudomonas aeruginosa) on these surfaces were studied. Mouse RAW 264.7 macrophage cells were used to assess the cell adhesion and inflammatory response by quantifying the expression levels of proinflammatory cytokines namely TNFalpha and IL1beta by measuring their mRNA profiles in the cells using real-time polymerase chain reaction (RT-PCR) normalized to the house keeping gene GAPDH. Whilst mouse L-929 fibroblast cells were used to assess the propensity for the materials to support fibroblast cell adhesion. A decrease in the adhesion of S. aureus by 63% and P. aeruginosa by 49% was observed on sulfobetaine modified PMMA films after 4 h. In all the cases, sulfobetaine modified PMMA films reduced cellular adhesion events (*P < 0.05) with respect to the base materials, which could be linked to the reduced protein adsorption observed on these surfaces. The cellular inflammatory response was suppressed on sulfobetaine modified substrates as expression levels of pro-inflammatory cytokines (TNFalpha and IL1beta) was found to be up regulated on bare PMMA, while it was significantly lower on sulfobetaine modified PMMA (**P < 0.001). Thus the sulfobetaine entrapment process can be applied on polymethylmethacrylate in order to achieve low biointeractions and reduced inflammatory host responses for various biomedical and biotechnological applications.

Predicting Dross Formation in Aluminium Melt Transfer Operations

Aluminium melt transfer operations can lead to significant amounts of dross formation as a result of chemical oxidation and physical entrapment processes. It has been suggested that these activities may contribute up to 50% of the total metal loss of ~1% in a typical primary aluminium smelter (i.e. 2,500 tonne/annum (tpa) in a smelter of 500,000tpa output). This is a large financial loss to any company, and also, in the new CO2-conscious era, it also represents a significant carbon footprint to ameliorate. A significant proportion of this metal loss may be prevented by adopting more efficient melt transfer strategies that reduce splashing and turbulence thereby resulting in reduced oxide and therefore dross formation. Optimisation of such systems is normally achieved by trial-and-error approaches, however a clear opportunity exists for rapid optimisation by employing computational modelling to explore the effects of changed equipment design and process conditions, such as tilt speed, spout height, spout geometry, etc. In the present paper, the Smoothed Particle Hydrodynamics (SPH) modeling method is used to predict the amount of oxide generated during molten metal transfers from a 500kg capacity tilting crucible furnace into a heated sow mould. Various conditions were tested. An oxidation model based on skimming trials performed in a laboratory-scale (8kg) oxidation rig is employed in the simulation. The predicted oxide from the simulations is compared against those of the experimental pours. It is anticipated that the validated model will be used for modifying the design and optimizing the operation of various melt transfer operations occurring in the aluminium industry.

Characterization, stabilization and activity of uricase loaded in lipid vesicles

Uricase-containing lipid vesicles (UOXLVs) were prepared by reverse-phase evaporation method with high efficiency and the characteristics of UOXLVs were described. The average size and zeta potential of UOXLVs obtained by the optimized formulation were 205.47 nm and −37.33 mV, respectively. Uricase was encapsulated in the alkaline aqueous phase of the lipid vesicle and the stability of its tetrameric structure was thus improved and its activity preserved. The storage stability of uricase in lipid vesicles was significantly increased compared to that of free uricase at 4 °C in borate buffer of pH 8.5. At 55 °C, free uricase was deactivated much more quickly especially at lower concentration predominantly due to enhanced dissociation of uricase into subunits. An intrinsic tryptophan of uricase recovered from the lipid vesicle thermally treated at 55 °C revealed that a partially denatured uricase molecule was stabilized through its hydrophobic interaction with lipid vesicle membrane. This interaction was depressed mainly by dissociation of uricase into subunits. At the physiological pH, significant increase of enzyme activity was found for the uricase entrapped in the lipid vesicles (1.8 times that of free uricase) at their respective optimum pH. The shift of optimum pH and increased uricolytic activity suggested the conformation change of the uricase during the entrapment process. The stability to proteolytic digestion was increased obviously by entrapping the uricase in the lipid vesicles. UOXLVs also showed relatively slower loss in activity compared with free uricase when treated with some chemical reagents. Lastly, in vitro study explicitly indicated that the uricase entrapped by UOXLVs possessed higher uricolytic activity than that of native uricase solution.

Synthesis of block copolymers for surface functionalization with stimuli-responsive macromolecules

Abstract Using block copolymers with poly(n-butyl acrylate) (PBA) as anchor block being capable to tether the temperature-responsive block poly(N-isopropylacrylamide) (PNIPAAm) to the surface, polysulfone (PSf) films were functionalized applying an adsorption/surface entrapment process. Homo and block copolymer synthesis was investigated applying atom transfer radical polymerization (ATRP) using tris(2-(dimethylamino)ethyl)amine (Me6TREN), CuCl and N,N-dimethylformamide (DMF). On basis of the determined critical micelle concentration of the block copolymers, surface functionalization of PSf was performed from an aqueous solution containing 25 vol% dimethylacetamide. These functionalized surfaces exhibit reversible temperature dependent properties due to the lower critical solution temperature (LCST) of PNIPAAm as can be proven by contact angle measurement. Furthermore, the beneficial effect of the PBA block with adjusted molecular weight on the stability of these coatings was proven. This surface functionalization method has various potential applications and the resulting surfaces are anticipated to exhibit actively triggerable ‘chaotic’ properties as basis of an efficient anti-biofouling strategy.

The Biocompatibility of Sulfobetaine Engineered Poly (Ethylene Terephthalate) by Surface Entrapment Technique

Sulfobetaine-modified poly(ethylene terephthalate) (PET) systems were created by physically entrapping the zwitterionic species on the PET surface. The presence of the sulfobetiane molecules on these surfaces were verified by ATR-FTIR and SEM-EDAX analysis, while wettability of the films was investigated by water contact angle measurements. The blood compatibility of the modified films was evaluated by platelet adhesion in human platelet-rich plasma (PRP). The adhesion and inflammatory response of Mouse RAW 264.7 macrophage cells were studied. The surface induced cellular inflammatory response was determined by quantifying the expression levels of proinflammatory cytokines namely TNF-alpha and IL-1beta by measuring their mRNA profiles in the cells using real time polymerase chain reaction normalized to the housekeeping gene GAPDH. L-929 fibroblast cells were used to assess the propensity of the materials to support the fibroblast cell adhesion. A lower platelet adhesion and activation were observed on the sulfobetaine-modified PET film incubated in PRP after 2h when compared to control. The modified film reduced cellular adhesion events ( p<0.05) with respect to the base material, which could be linked to the reduced protein adsorption observed on this surface. The cellular inflammatory response was suppressed on sulfobetaine-modified substrate. Expression levels of pro-inflammmatory cytokines (TNF-alpha and IL-1beta) was found to be upregulated on bare PET, while it was significantly lower on modified PET ( p<0.001). Thus the sulfobetaine entrapment process can be applied on PET in order to achieve low biointeractions and reduced inflammatory host response for various biomedical and biotechnological applications.

The phenomenon of bubble entrapment during capsule formation

Polymer capsules are formed following the impact of viscous poly-anion drops onto a deep pool of water-like poly-cation solution. During impact, an air bubble is often trapped on the drop/capsule surface, affecting the membrane quality locally. This entrapment has been experimentally examined for a typical anion–cation pair through detailed imaging of the impact crater. Experiments show that the bubble entrapment is caused by the collapse of the impact crater above the top surface of the submerged-and-reacting drop. Locally, the bubble pinch-off can be viewed as the continuous thinning of a gas filament driven by the rebounding bulk flow. In the low impact Weber number ( We) regime, the data suggests that both surface tension and inertia govern the entrapment process, whereas, for higher Weber numbers the process is inertia-dominated. The transition condition is found to be coincident with the observation of the critical cone angle for the impact crater, seen in inviscid non-reacting drop impact.

TecoflexTM functionalization by curdlan and its effect on protein adsorption and bacterial and tissue cell adhesion

Curdlan modified polyurethane was created by physically entrapping the former on TecoflexTM surface. ATR-FT-IR, SEM-EDAX and AFM analysis revealed the formation of stable thin curdlan layer on the film. Contact-angle measurements showed that the modified film was highly hydrophilic. Confocal laser scanning microscopy showed the existence of entrapped layer of approximately 20-25 microm in depth. Surface entrapment of curdlan minimized both protein adsorption and mouse L929 fibroblast cell adhesion relative to the control. Surface induced cellular inflammatory response was determined from the expression levels of proinflammatory cytokine TNF-alpha, by measuring their mRNA profiles in the cells using real time polymerase chain reaction (RT-PCR) normalized to the housekeeping gene GAPDH. The inflammatory response was suppressed on the modified substrate as expression of TNF-alpha mRNA was found to be up regulated on TecoflexTM, while it was significantly lower on curdlan substrate. The adhesion of S. aureus decreased by 62% on curdlan modified surface. Using such simple surface entrapment process, it will be possible to develop well-defined surface modifications that promote specific cell interactions and perhaps better performance in the long-term as implant.

Deformação neógena e suas implicações na estruturação dos campos de petróleo na região de Icapuí-Ponta Grossa (CE), Bacia Potiguar emersa

In coastal cliffs at the western portion of the Potiguar Basin (so-called Aracati Platform), the Barreiras Formation, of miocene age, displays structures pointing to high strain deformation. Detailed mapping of faults and folds geometry in the Barreiras Formation leds to recognition of extensional structures (at Ponta Grossa village) and contractional oblique structures (Vila Nova, next to Icapui town), both of them related to a transcurrent system bearing NE (at these locations) and NW trends (Afonso Bezerra Fault, in the central portion of the basin). These data point to a neogene stress field which generated faults, folds and hydroplastics structures, including SL fabrics and shear zones, as well as reactivated older structures in the underlying neocretaceus sedimentary section. Reinterpretation of seismic sections from this region and other geological data at several places in the Potiguar Basin outline structures which are correlated (in style and kinematic regime) throughout the siliciclastic rocks of the Acu Formation, limestones of the Jandaira Formation and younger basalts of the Macau Formation, whose age straddles the Oligocene-Miocene boundary. This structural framework recognized at the surface has to be compatible with subsurface deformation as observed in seismic sections, which includes pulses/events of older, Neocretaceus to Paleogene age. This model has important implications as regards the structure (geometry, kinematics, age op traps) of oil reservoirs (especially the sandstones of the Acu Formation, in the Fazenda Belem Oil Field) and the processes of migration and hydrocarbon entrapment at this region of the Potiguar Basin.