Sample records for incorporating electrokinetic effects

  1. Electrokinetic effects in power transformers

    Microsoft Academic Search

    J. K. Nelson; M. J. Lee; S. J. Salon

    1992-01-01

    Electrokinetic effects such as static electrification can cause catastrophic failures in large forced-oil-cooled power transformers. Experimental and analytical studies confirm that surface charges can significantly impact dielectric integrity. The project team used a closed-loop oil circulation system and full-scale models of power transformer cooling duct structures to conduct controlled experiments. They measured charge density in the oil-resulting from flow through

  2. Electrokinetic effects near a membrane

    NASA Astrophysics Data System (ADS)

    Lacoste, David

    2009-03-01

    We discuss the electrostatic and electrokinetic contribution to the elastic moduli of a cell or artificial membrane placed in an electrolyte and driven by a DC electric field. The field drives ion currents across the membrane, through specific channels, pumps or natural pores. In steady state, charges accumulate in the Debye layers close to the membrane, modifying the membrane elastic moduli. We first study a model of a membrane of zero thickness, later generalizing this treatment to allow for a finite thickness and finite dielectric constant. Our results clarify and extend the results presented in [D. Lacoste, M. Cosentino Lagomarsino, and J. F. Joanny, Europhys. Lett., 77, 18006 (2007)], by providing a physical explanation for a destabilizing term proportional to kps^3 in the fluctuation spectrum, which we relate to a nonlinear (E^2) electro-kinetic effect called induced-charge electro-osmosis (ICEO). Recent studies of ICEO have focused on electrodes and polarizable particles, where an applied bulk field is perturbed by capacitive charging of the double layer and drives flow along the field axis toward surface protrusions; we predict similar ICEO flows around driven membranes, due to curvature-induced tangential fields within a non-equilibrium double layer, which hydrodynamically enhance protrusions.

  3. Unsteady electrokinetic microfluidics with hydrodynamic slippage effect

    NASA Astrophysics Data System (ADS)

    Chun, Myung-Suk; Yang, Yoona; Complex Fluids Team

    2014-03-01

    The nature of low Reynolds number flows and confined spaces inherent in microscale or extended nanoscale channels imply the significant influence of solid wall boundaries. We investigate the unsteady pulsatile electrokinetic flows by extending our previous simulations concerning electrokinetic microfluidics. The body force originated from between the nonlinear Poisson-Boltzmann field and the flow-induced electric field is employed in Navier-Stokes equation, and Nernst-Planck equation in connection with the net current conservation is further coupled. Our explicit model allows one to quantify the effects of time delay, oscillating frequency, and conductance of the Stern layer, considering the fluid slippage at hydrophobic surfaces and the electric double layer interaction. This presentation reports new results regarding the implication of pressure pulsations toward realizing mechanical to electrical energy transfer with high conversion efficiency. A combined role of the fluid slippage and conductance of channel wall is examined to obtain possible enhancements of streamwise velocity and streaming potential, with taking advantage of pulsating pressure field. Note that our framework can serve as a useful basis for micro/nanofluidics design.

  4. Electrokinetic effects on detection time of nanowire biosensor

    NASA Astrophysics Data System (ADS)

    Liu, Yaling; Guo, Qingjiang; Wang, Shunqiang; Hu, Walter

    2012-04-01

    We develop a multiphysics model to study the contribution of electrokinetics on the biomolecular detection process and provide a physical explanation of the two to three orders of magnitude difference in detection time between experimental results and theoretical predications at ultralow concentration. The electrokinetic effects, including electrophoretic force and electroosmotic flow, have been systematically studied under various sensor design and test conditions. In a typical single nanowire-based sensor, it is found that electrokinetic effects could result in a reduction of detection time over 90 times, compared with that induced by pure biomolecular diffusion. The detection time difference is further enhanced by increasing the applied gate voltage or the number of nanowires. It is proposed that accelerated biomolecular detection at ultralow concentration could be achieved by appropriate combinations of electrokinetic effects and nanowire sensor design.

  5. An integrated method incorporating sulfur-oxidizing bacteria and electrokinetics to enhance removal of copper from contaminated soil

    SciTech Connect

    Maini, G.; Sharman, A.K.; Sunderland, G.; Knowles, C.J.; Jackman, S.A.

    2000-03-15

    The combination of bioleaching and electrokinetics for the remediation of metal contaminated land has been investigated. In bioleaching, bacteria convert reduced sulfur compounds to sulfuric acid, acidifying soil and mobilizing metal ions. In electrokinetics, DC current acidifies soil, and mobilized metals are transported to the cathode by electromigration. When bioleaching was applied to silt soil artificially contaminated with seven metals and amended with sulfur, bacterial activity was partially inhibited and limited acidification occurred. Electrokinetic treatment of silt soil contaminated solely with 1000 mg/kg copper nitrate showed 89% removal of copper from the soil within 15 days. To combine bioleaching and electrokinetics sequentially, preliminary partial acidification was performed by amending copper-contaminated soil with sulfur (to 5% w/w) and incubating at constant moisture (30% w/w) and temperature (20 C) for 90 days. Indigenous sulfur oxidizing bacteria partially acidified the soil from pH 8.1 to 5.4. This soil was then treated by electrokinetics yielding 86% copper removal in 16 days. In the combined process, electrokinetics stimulated sulfur oxidation, by removing inhibitory factors, yielding a 5.1-fold increase in soil sulfate concentration. Preacidification by sulfur-oxidizing bacteria increased the cost-effectiveness of the electrokinetic treatment by reducing the power requirement by 66%.

  6. Ion-Specific Anomalous Electrokinetic Effects in Hydrophobic Nanochannels

    NASA Astrophysics Data System (ADS)

    Huang, David M.; Cottin-Bizonne, Cécile; Ybert, Christophe; Bocquet, Lydéric

    2007-04-01

    We show with computer simulations that anomalous electrokinetic effects, such as ion specificity and nonzero zeta potentials for uncharged surfaces, are generic features of electro-osmotic flow in hydrophobic channels. This behavior is due to the stronger attraction of larger ions to the “vapor-liquidlike” interface induced by a hydrophobic surface. We propose an analytical model involving a modified Poisson-Boltzmann description for the ion density distributions that quantitatively predicts the anomalous flow profiles. This description includes as a crucial component an ion-size-dependent hydrophobic solvation energy. These results provide an effective framework for predicting ion-specific effects, with potentially important implications for biological modeling.

  7. ac electrokinetic micropumps: The effect of geometrical confinement, Faradaic current injection, and nonlinear surface capacitance

    E-print Network

    ac electrokinetic micropumps: The effect of geometrical confinement, Faradaic current injection demonstrated that ac electrokinetic micropumps permit integrable, local, and fast pumping velocities mm-on-a-chip systems require micropumps and valves to manipulate small volumes of a liquid sample 1 . Often large

  8. Analytical and Numerical Study of Joule Heating Effects on Electrokinetically Pumped Continuous Flow PCR Chips

    E-print Network

    Le Roy, Robert J.

    Analytical and Numerical Study of Joule Heating Effects on Electrokinetically Pumped Continuous, and the potential for integration.1-3 Joule heating is inevitable when electrokinetic pumping is used Form: December 8, 2007 Joule heating is an inevitable phenomenon for microfluidic chips involving

  9. Viscoelastic effects on electrokinetic particle focusing in a constricted microchannel.

    PubMed

    Lu, Xinyu; DuBose, John; Joo, Sang Woo; Qian, Shizhi; Xuan, Xiangchun

    2015-01-01

    Focusing suspended particles in a fluid into a single file is often necessary prior to continuous-flow detection, analysis, and separation. Electrokinetic particle focusing has been demonstrated in constricted microchannels by the use of the constriction-induced dielectrophoresis. However, previous studies on this subject have been limited to Newtonian fluids only. We report in this paper an experimental investigation of the viscoelastic effects on electrokinetic particle focusing in non-Newtonian polyethylene oxide solutions through a constricted microchannel. The width of the focused particle stream is found NOT to decrease with the increase in DC electric field, which is different from that in Newtonian fluids. Moreover, particle aggregations are observed at relatively high electric fields to first form inside the constriction. They can then either move forward and exit the constriction in an explosive mode or roll back to the constriction entrance for further accumulations. These unexpected phenomena are distinct from the findings in our earlier paper [Lu et al., Biomicrofluidics 8, 021802 (2014)], where particles are observed to oscillate inside the constriction and not to pass through until a chain of sufficient length is formed. They are speculated to be a consequence of the fluid viscoelasticity effects. PMID:25713690

  10. Grain-size to effective pore-size transformation derived from electrokinetic theory

    Microsoft Academic Search

    P. W. J. Glover; E. Walker

    2009-01-01

    Mostpermeabilitymodelsuseeffectivegrainsizeoreffec- tiveporesizeasaninputparameter.Untilnow,anefficacious way of converting between the two has not been available. We propose a simple conversion method for effective grain diameter and effective pore radius using a relationship de- rived by comparing two independent equations for perme- ability, based on the electrokinetic properties of porous me- dia. The relationship, which we call the theta function, is not dependent upon

  11. Sub-Grid Modeling of Electrokinetic Effects in Micro Flows

    NASA Technical Reports Server (NTRS)

    Chen, C. P.

    2005-01-01

    Advances in micro-fabrication processes have generated tremendous interests in miniaturizing chemical and biomedical analyses into integrated microsystems (Lab-on-Chip devices). To successfully design and operate the micro fluidics system, it is essential to understand the fundamental fluid flow phenomena when channel sizes are shrink to micron or even nano dimensions. One important phenomenon is the electro kinetic effect in micro/nano channels due to the existence of the electrical double layer (EDL) near a solid-liquid interface. Not only EDL is responsible for electro-osmosis pumping when an electric field parallel to the surface is imposed, EDL also causes extra flow resistance (the electro-viscous effect) and flow anomaly (such as early transition from laminar to turbulent flow) observed in pressure-driven microchannel flows. Modeling and simulation of electro-kinetic effects on micro flows poses significant numerical challenge due to the fact that the sizes of the double layer (10 nm up to microns) are very thin compared to channel width (can be up to 100 s of m). Since the typical thickness of the double layer is extremely small compared to the channel width, it would be computationally very costly to capture the velocity profile inside the double layer by placing sufficient number of grid cells in the layer to resolve the velocity changes, especially in complex, 3-d geometries. Existing approaches using "slip" wall velocity and augmented double layer are difficult to use when the flow geometry is complicated, e.g. flow in a T-junction, X-junction, etc. In order to overcome the difficulties arising from those two approaches, we have developed a sub-grid integration method to properly account for the physics of the double layer. The integration approach can be used on simple or complicated flow geometries. Resolution of the double layer is not needed in this approach, and the effects of the double layer can be accounted for at the same time. With this approach, the numeric grid size can be much larger than the thickness of double layer. Presented in this report are a description of the approach, methodology for implementation and several validation simulations for micro flows.

  12. ac electrokinetic micropumps: The effect of geometrical confinement, Faradaic current injection, and nonlinear surface capacitance

    Microsoft Academic Search

    Laurits Højgaard Olesen; Henrik Bruus; Armand Ajdari

    2006-01-01

    Recent experiments have demonstrated that ac electrokinetic micropumps permit integrable, local, and fast pumping (velocities ˜mm\\/s ) with low driving voltage of a few volts only. However, they also displayed many quantitative and qualitative discrepancies with existing theories. We therefore extend the latter theories to account for three experimentally relevant effects: (i) vertical confinement of the pumping channel, (ii) Faradaic

  13. Numerical electrokinetics.

    PubMed

    Schmitz, R; Dünweg, B

    2012-11-21

    A new lattice method is presented in order to efficiently solve the electrokinetic equations, which describe the structure and dynamics of the charge cloud and the flow field surrounding a single charged colloidal sphere, or a fixed array of such objects. We focus on calculating the electrophoretic mobility in the limit of small driving field, and systematically linearize the equations with respect to the latter. This gives rise to several subproblems, each of which is solved by a specialized numerical algorithm. For the total problem we combine these solvers in an iterative procedure. Applying this method, we study the effect of the screening mechanism (salt screening versus counterion screening) on the electrophoretic mobility, and find a weak non-trivial dependence, as expected from scaling theory. Furthermore, we find that the orientation of the charge cloud (i.e. its dipole moment) depends on the value of the colloid charge, as a result of a competition between electrostatic and hydrodynamic effects. PMID:23113993

  14. Effects of surface roughness and electrokinetic heterogeneity on electroosmotic flow in microchannel

    NASA Astrophysics Data System (ADS)

    Masilamani, Kannan; Ganguly, Suvankar; Feichtinger, Christian; Bartuschat, Dominik; Rüde, Ulrich

    2015-06-01

    In this paper, a hybrid lattice-Boltzmann and finite-difference (LB-FD) model is applied to simulate the effects of three-dimensional surface roughness and electrokinetic heterogeneity on electroosmotic flow (EOF) in a microchannel. The lattice-Boltzmann (LB) method has been employed to obtain the flow field and a finite-difference (FD) method is used to solve the Poisson-Boltzmann (PB) equation for the electrostatic potential distribution. Numerical simulation of flow through a square cross-section microchannel with designed roughness is conducted and the results are critically analysed. The effects of surface heterogeneity on the electroosmotic transport are investigated for different roughness height, width, roughness interval spacing, and roughness surface potential. Numerical simulations reveal that the presence of surface roughness changes the nature of electroosmotic transport through the microchannel. It is found that the electroosmotic velocity decreases with the increase in roughness height and the velocity profile becomes asymmetric. For the same height of the roughness elements, the EOF velocity rises with the increase in roughness width. For the heterogeneously charged rough channel, the velocity profile shows a distinct deviation from the conventional plug-like flow pattern. The simulation results also indicate locally induced flow vortices which can be utilized to enhance the flow and mixing within the microchannel. The present study has important implications towards electrokinetic flow control in the microchannel, and can provide an efficient way to design a microfluidic system of practical interest.

  15. Electrokinetic effects in catalytic platinum-insulator Janus swimmers

    NASA Astrophysics Data System (ADS)

    Ebbens, S.; Gregory, D. A.; Dunderdale, G.; Howse, J. R.; Ibrahim, Y.; Liverpool, T. B.; Golestanian, R.

    2014-06-01

    The effect of added salt on the propulsion of Janus platinum-polystyrene colloids in hydrogen peroxide solution is studied experimentally. It is found that micromolar quantities of potassium and silver nitrate salts reduce the swimming velocity by similar amounts, while leading to significantly different effects on the overall rate of catalytic breakdown of hydrogen peroxide. It is argued that the seemingly paradoxical experimental observations could be theoretically explained by using a generalised reaction scheme that involves charged intermediates and has the topology of two nested loops.

  16. Ion size effects on the electrokinetics of salt-free concentrated suspensions in ac fields

    E-print Network

    Rafael Roa; Félix Carrique; Emilio Ruiz-Reina

    2012-08-01

    We analyze the influence of finite ion size effects in the response of a salt-free concentrated suspension of spherical particles to an oscillating electric field. Salt-free suspensions are just composed of charged colloidal particles and the added counterions released by the particles to the solution, that counterbalance their surface charge. In the frequency domain, we study the dynamic electrophoretic mobility of the particles and the dielectric response of the suspension. We find that the Maxwell-Wagner-O'Konski process associated with the counterions condensation layer, is enhanced for moderate to high particle charges, yielding an increment of the mobility for such frequencies. We also find that the increment of the mobility grows with ion size and particle charge. All these facts show the importance of including ion size effects in any extension attempting to improve standard electrokinetic models.

  17. Lattice Boltzmann simulations of electrokinetic coupling : effects of rugosity and local conductivity

    NASA Astrophysics Data System (ADS)

    Fiorentino, Eve-Agnès; Toussaint, Renaud; Jouniaux, Laurence

    2015-04-01

    Streaming-potentials are produced by electrokinetic effects in relation to fluid flow, and are used for geophysical prospecting. The electrokinetic coupling is induced by the coupling between the fluid flow and the electrical flow, which results from the presence of an electrical double layer at the rock/pore water interface. When fluid flows through a porous medium, it gives rise to an electric streaming current, counterbalanced by a conduction current, leading to a resulting measurable electrical voltage. Streaming current generation is well understood in water-saturated porous media, but the streaming potential coefficient at very-low and very-high salinities can show a non-linear behaviour. The aim of this study is to model the streaming potential coefficient using Lattice Boltzmann simulations and to quantify the effect of parameters such as fluid conductivity and rugosity. The lattice Boltzmann method is computational fluid dynamics technique that allows to solve advection and diffusion phenomena. We implement a coupled lattice Boltzmann algorithm that solves both the flow in a rock channel and the electrical diffusion to calculate the streaming potential coefficient (ratio between the created potential difference and the applied pressure gradient) in various situations. In this study, we aim at quantifying the change that is brought by taking into account the dependence of the local fluid conductivity on the local concentration. We also observe the influence of a rough surface on the behaviour of this coefficient with the fluid salinity. We try to generate non-linearities regarding the theoretical prediction of the streaming potential coefficient with a view to explaining existing experimental measurements.

  18. Electrokinetic behavior of two touching inhomogeneous biological cells and colloidal particles: Effects of multipolar interactions

    E-print Network

    Huang, Ji-Ping

    Electrokinetic behavior of two touching inhomogeneous biological cells and colloidal particles inhomogeneous colloidal particles and biological cells. These inhomogeneous particles are treated as graded ones Identification and analysis of cell populations and (micro) biological particles are essential in many practical

  19. Electrokinetic pump

    DOEpatents

    Patel, Kamlesh D. (Dublin, CA)

    2007-11-20

    A method for altering the surface properties of a particle bed. In application, the method pertains particularly to an electrokinetic pump configuration where nanoparticles are bonded to the surface of the stationary phase to alter the surface properties of the stationary phase including the surface area and/or the zeta potential and thus improve the efficiency and operating range of these pumps. By functionalizing the nanoparticles to change the zeta potential the electrokinetic pump is rendered capable of operating with working fluids having pH values that can range from 2-10 generally and acidic working fluids in particular. For applications in which the pump is intended to handle highly acidic solutions latex nanoparticles that are quaternary amine functionalized can be used.

  20. Electrokinetic decontamination of millpond sludge

    SciTech Connect

    Khan, L.I.; Rahman, M. [Cleveland State Univ., OH (United States)

    1995-12-31

    Electrokinetic decontamination of high clay containing soils is a developing technology. EPA has recently designated electrokinetic method as a viable insitu process and interested parties are attempting to apply this method at contaminated sites which have inherently low permeability soils and otherwise difficult to remediate. Electrokinetic process induces a high water flow rate in clayey soils by the mechanism known as electro-osmosis and is primarily suitable for heavy metal removal. However, chemical reactions and sorption of metal ions within the soil matrix may adversely effect the decontamination process. Presence of a significant amount of heavy molecular weight organic matter within the soil pores may reduce the mobility of the heavy metals due to the formation of insoluble organometallic compounds. There has been some research in removing heavy metals and low concentration organic matter from soil by the electrokinetic method. The effects of soil organic matter on heavy metal removal by electrokinetic method has not been adequately investigated and several unanswered questions remain about the efficiency of the process under such circumstances. This paper is a partial result of an electrokinetic decontamination investigation for Zn, Ph and Mn removal from a soil with high organic matter content. A foundry millpond sludge from North East Ohio was chosen as a high organic matter containing matrix.

  1. Electrokinetic Power Generation from Liquid Water Microjets

    SciTech Connect

    Duffin, Andrew M.; Saykally, Richard J.

    2008-02-15

    Although electrokinetic effects are not new, only recently have they been investigated for possible use in energy conversion devices. We have recently reported the electrokinetic generation of molecular hydrogen from rapidly flowing liquid water microjets [Duffin et al. JPCC 2007, 111, 12031]. Here, we describe the use of liquid water microjets for direct conversion of electrokinetic energy to electrical power. Previous studies of electrokinetic power production have reported low efficiencies ({approx}3%), limited by back conduction of ions at the surface and in the bulk liquid. Liquid microjets eliminate energy dissipation due to back conduction and, measuring only at the jet target, yield conversion efficiencies exceeding 10%.

  2. Electric Potential Variations on a Poplar: Beyond Electrokinetic Effects Associated With Sap Flow

    NASA Astrophysics Data System (ADS)

    Gibert, D.; Le Mouël, J.; Lambs, L.; Nicollin, F.; Conil, F.; Perrier, F.

    2004-12-01

    Electric potential has been monitored since December 2003 in the roots and at two circumferences and one vertical profile in a standing poplar (Populus incognitus). Electric potential is sampled using 5 mm diameter stainless steel rods, inserted 5 mm deep in the cambium, and is referenced to an unpolarizable Petiau electrode installed 80 cm deep in the soil. Various types of signals are observed. Transient signals with long relaxation times affecting some electrodes simultaneously, may be contact potentials triggered by condensation and evaporation. Diurnal variations are observed which present a seasonal variation. During winter, diurnal variations depend on the measurement point, with variable amplitudes and sometimes anticorrelations between electrodes. By contrast, a stable and coherent organization is established in the spring, with larger amplitudes, and lasts during summer. Such signals have been reported previously (Koppan et al., 2000; Morat et al., 1994; Fensom, 1963), have been interpreted as electrokinetic effects associated with sap flow. However, a comparison of the electrical signals with a measurement of the sap flow by a heat flow method, shows that the electrical variation, although clearly correlated to sap flow, is not simply proportional to it. In a living system, electrokinetic effects, in addition to thermoelectrical effects, are probably modified significantly by additional electrochemical effects, such as membrane diffusion potentials, ion active transport by proteins, and action potentials. Such effects have been evidenced in laboratory experiments with plants (e.g., Fromm and Hei, 1998). Electric potential variations in trees may thus reveal mechanisms not accessible by other methods, and maybe reveal new aspects of the physics of living systems. A better understanding of the electrical response of trees to meteorological, chemical or biological forcing may improve the knowledge of transfer processes between the soil and the atmosphere. This is important for the modeling of water and carbon balance in relation to climate change, as well as of the contribution of trees to the migration, retention and dispersion of contaminants. Fensom, D. S., The bioelectric potentials of plants and their functional significance : V. Some daily and seasonal changes in the electrical potential and resistance of living trees, Canadian J. Botany, 41, 831-851, 1963. Fromm, J., and H. Fei, Electrical signaling and gas exchange in maize plants of drying soil, Plant Science, 132, 203-213, 1998. Koppan, A., L. Szarka, and V. Wesztergom, Annual fluctuation in amplitudes of daily variations of electrical signals measured in the trunk of a standing tree, C. R. Acad. Sci. Paris, 323, 559-563, 2000. Morat, P., J.-L. Le Mouël, and A. Granier, Electrical potential on a tree. A measurement of the sap flow ?, C. R. Acad. Sci. Paris, 317, 98-101, 1994.

  3. [Effects of ionic liquids on micellar microstructures and separation performance in micellar electrokinetic chromatography].

    PubMed

    Yu, Meijuan; Hang, Dong; Cao, Yuhua

    2011-02-01

    The effects of ionic liquids on micellar microstructures and separation performance in micellar electrokinetic chromatography (MEKC) were investigated. The experimental results showed that the addition of ionic liquids into micellar system would result in a decreased micellar surface charge density, an enlarged size of micelle and a slight enhancement of the polarity in the inner core of micelle. Prednisone, hydrocortisone and prednisolone were analyzed with MEKC to evaluate the separation performance. Hydrocortisone and prednisolone could not be separated in sodium lauryl sulfate (SDS) micellar system. However, the three analytes could be baseline separated in the mixed system of ionic liquids and SDS (20 mmol/L SDS-10 mmol/L 1-butyl-3-methyl imidazolium tetrafluoroborate-50 mmol/L borax, pH 8.4) within 17 min. Notably, the linearities of the three analytes ranged from 2 to 100 mg/L and the detection limits based on the ratio of signal to noise of 3 were 1.0, 1.1 and 1.0 mg/L for prednisone, hydrocortisone and prednisolone, respectively. The method has been used in the analysis of corticosteroids in cosmetic samples. The recoveries for the three analytes were between 95. 1% and 117%. This method has the advantages of simple pretreatment, high accuracy, good reproducibility, and can be applied to the quality control of cosmetics. PMID:21598512

  4. Electrokinetic behavior of two touching inhomogeneous biological cells and colloidal particles: effects of multipolar interactions.

    PubMed

    Huang, J P; Karttunen, Mikko; Yu, K W; Dong, L; Gu, G Q

    2004-05-01

    We present a theory to investigate electrokinetic behavior, namely, electrorotation and dielectrophoresis under alternating current (ac) applied fields for a pair of touching inhomogeneous colloidal particles and biological cells. These inhomogeneous particles are treated as graded ones with physically motivated model dielectric and conductivity profiles. The mutual polarization interaction between the particles yields a change in their respective dipole moments, and hence in the ac electrokinetic spectra. The multipolar interactions between polarized particles are accurately captured by the multiple images method. In the point-dipole limit, our theory reproduces the known results. We find that the multipolar interactions as well as the spatial fluctuations inside the particles can affect the ac electrokinetic spectra significantly. PMID:15244819

  5. Effects of electrokinetic treatment of a heavy metal contaminated soil on soil enzyme activities

    Microsoft Academic Search

    Long Cang; Dong-Mei Zhou; Quan-Ying Wang; Dan-Ya Wu

    2009-01-01

    There is a growing concern on the potential application of a direct current (DC) electric field to soil for removing contaminants, but little is known about its impact on soil enzyme activities. This study investigated the change of enzyme activities of a heavy metal contaminated soil before and after electrokinetic (EK) treatments at lab-scale and the mechanisms of EK treatment

  6. Electrokinetic delivery of persulfate to remediate PCBs polluted soils: effect of injection spot.

    PubMed

    Fan, Guangping; Cang, Long; Fang, Guodong; Qin, Wenxiu; Ge, Liqiang; Zhou, Dongmei

    2014-12-01

    Persulfate-based in situ chemical oxidation (ISCO) is a promising technique for the remediation of organic compounds contaminated soils. Electrokinetics (EK) provides an alternative method to deliver oxidants into the target zones especially in low permeable-soil. In this study, the flexibility of delivering persulfate by EK to remediate polychlorinated biphenyls (PCBs) polluted soil was investigated. 20% (w/w) of persulfate was injected at the anode, cathode and both electrodes to examine its transport behaviors under electrical field, and the effect of field inversion process was also evaluated. The results showed that high dosage of persulfate could be delivered into S4 section (near cathode) by electroosmosis when persulfate was injected from anode, 30.8% of PCBs was removed from the soil, and the formed hydroxyl precipitation near the cathode during EK process impeded the transportation of persulfate. In contrast, only 18.9% of PCBs was removed with the injection of persulfate from cathode, although the breakthrough of persulfate into the anode reservoir was observed. These results indicated that the electroosmotic flow is more effective for the transportation of persulfate into soil. The addition of persulfate from both electrodes did not significantly facilitate the PCBs oxidation as well as the treatment of electrical field reversion, the reinforced negative depolarization function occurring in the cathode at high current consumed most of the oxidant. Furthermore, it was found that strong acid condition near the anode favored the oxidation of PCBs by persulfate and the degradation of PCBs was in consistent with the oxidation of Soil TOC in EK/persulfate system. PMID:25193794

  7. Microemulsion electrokinetic chromatography of corticosteroids. Effect of surfactants and cyclodextrins on the separation selectivity.

    PubMed

    Pomponio, Romeo; Gotti, Roberto; Fiori, Jessica; Cavrini, Vanni

    2005-07-15

    The separation of neutral hydrophobic corticosteroids (cortisone, cortisone acetate, hydrocortisone, hydrocortisone acetate, prednisolone and prednisolone acetate) by microemulsion electrokinetic chromatography (MEEKC) was studied. In the preparation of microemulsion, heptane was the solvent, n-butanol the co-surfactant and, as anionic surfactants, sodium dodecyl sulfate (SDS) or taurodeoxycholic acid sodium salt (STDC) were employed. Using an acidic running buffer, (phosphate pH 2.5) a strong suppression of the electroosmotic flow (EOF) was observed; this resulted in a fast anodic migration of the analytes partitioned into the negatively charged microemulsion droplets. Under these conditions, STDC showed better separation of corticosteroids than the conventional SDS; however, the use of a single anionic surfactant did not provide the required selectivity. The addition of the neutral surfactant polyoxyethylene glycol octadecyl ether (Brij 76) significantly altered the migration of each analytes allowing a better tuning of separation; however, in order to obtain adequate resolution between couples of adjacent critical peaks, the addition of neutral cyclodextrins (CDs) was found to be essential. This apparently complex system (CD-MEEKC), was optimized by studying the effect of the most important parameters affecting separation: STDC concentration, Brij 76 concentration, nature and concentration of cyclodextrins. Following a rational step-by-step approach, the optimised conditions providing the complete separation of the analytes were found to be: 4.0% STDC, 2.5% Brij 76, 6.6% n-butanol, 1.36% heptane and 85.54% of a solution 5 mM beta-CD in 50 mM phosphate buffer (pH 2.5). The optimized system was preliminary applied to the detection of corticosteroids related substances at impurity level and it could be considered a useful orthogonal alternative to HPLC methods. PMID:16013593

  8. Electrokinetic motion of heterogeneous particles Electrophoresis, induced-charge electrophoresis, transverse electrophoresis.

    E-print Network

    Bazant, Martin Z.

    Electrokinetic motion of heterogeneous particles Synonyms Electrophoresis, induced-charge electrophoresis, transverse electrophoresis. Definition The electrokinetic motion of heterogeneous particles due to the combined effects of electrophoresis, induced-charge electrophoresis, and dielectrophoresis

  9. Effect of low concentration sodium dodecyl sulfate on the electromigration of palonosetron hydrochloride stereoisomers in micellar electrokinetic chromatography.

    PubMed

    Hu, Shao-Qiang; Wang, Gui-Xia; Guo, Wen-Bo; Guo, Xu-Ming; Zhao, Min

    2014-05-16

    The effect of low concentrations of sodium dodecyl sulfate (SDS) on the separation of palonosetron hydrochloride (PALO) stereoisomers by micellar electrokinetic chromatography (MEKC) has been investigated. It was found that the addition of SDS prolongs the migration time and the migration order of four stereoisomers changes regularly with the SDS concentration. Good separations for all the four stereoisomers were achieved at appropriate SDS concentration. The effect of SDS on the electromigration (mobilities) of PALO stereoisomers has been studied, in order to explain its effect on the separation by MEKC. It was found that low concentrations of SDS added into the separation media forms negatively charged complexes with PALO stereoisomers and hence reverses their electromigration direction. Furthermore, the migration order between two enantiomeric pairs is also reversed because the enantiomeric pair with a bigger positive mobility than that of another pair turns to have a bigger negative mobility when bound with SDS. Based on these results, the effect of SDS on the MEKC separation of PALO stereoisomers was elucidated reasonably. The performance of the developed chiral MEKC method was validated by the analysis of a real sample. PMID:24709591

  10. Effect of electrokinetics on biodesulfurization of the model oil by Rhodococcus erythropolis PTCC1767 and Bacillus subtilis DSMZ 3256.

    PubMed

    Boshagh, Fatemeh; Mokhtarani, Babak; Mortaheb, Hamid Reza

    2014-09-15

    Biodesulfurization of the model oil using Rhodococcus erythropolis PTCC1767 (R. erythropolis) and Bacillus subtilis DSMZ 3256 (B. subtilis) strains assisted by applying electrokinetic was investigated as a novel method for desulfurization. The yield of biodesulfurization is low because it takes long time to be completed. Electrokinetic reduces the process time and accelerates degradation of the sulfur compounds. A mixture of normal hexadecane with 10mM dibenzotiophene (DBT) was employed as the model oil. The biodesulfurization experiments were initially performed. The results represented 34% and 62% DBT conversions after 1 and 6 days by R. erythropolis and the biodesulfurization yields were 11% and 36%, respectively. However, the DBT conversions for B. subtilis strain after 1 and 6 days were 31% and 55% and the biodesulfurization yields were 9% and 31%, respectively. The electrokinetic biodesulfurization experiments were studied at different current densities and the optimum current density was selected. According to the results, DBT conversion and biodesulfurization yield for R. erythropolis after 3 days were 76% and 39%, respectively, at the current density of 7.5 mA/cm(2). At the same conditions, the DBT conversion and biodesulfurization yield for B. subtilis were 71% and 37%, respectively. The experimental results indicate that the electrokinetic significantly reduces the biodesulfurization time. The combination of electrokinetic and biodesulfurization has the potential to obtain 'zero sulfur' products. PMID:25244073

  11. Effects of heavy metals on the electrokinetic properties of bacteria, yeast, and clay minerals

    SciTech Connect

    Collins, Y.E.

    1987-01-01

    The electrokinetic patterns of four bacteria (Bacillus subtilis, Bacillus megaterium, Pseudomonas aeruginosa, Agrobacterium radiobacter), two yeasts (Saccharomyces cerevisiae, Canida albicans), and two clay minerals (montmorillonite, kaolinite) in the presence of the chloride salts of heavy metals (Cd, Cr, Cu, Hg, Ni, Pb, Zn) and of Na and Mg were determined by microelectrophoresis. The cells and clays were net negatively charged at pH values above their isoelectric point (pI) in solutions of Na, Mg, Hg, and Pb with an ionic strength (..mu..) of 3 x 10/sup -4/. However, at pH values above pH 5.0, the charge of some bacteria, S. cerevisiae, and kaolinite changed to a net positive charge (charge reversal) in the presence of Cd, Cr, Cu, Ni, and Zn. The charge of the bacteria and S. cerevisiae also reversed in solution of Ni and Cu with a ..mu.. > 3 x 10/sup -4/, whereas there was no reversal in solutions with a ..mu.. < 3 x 10/sup -4/. The clays became net positively charged when the ..mu.. of Cu was > 3 x 10/sup -4/ and that of Ni was > 1.5 x 10/sup -4/. The charge of the cells and clays also reversed in solutions containing both Mg and Ni or both Cu and Ni (except montmorillonite) but not in solutions containing both Mg and Cu (except kaolinite) (..mu.. = 3 x 10/sup -4/). The pI of the cells in the presence of some heavy metals, especially Ni and Cr, was at higher pH values than in the presence of Na and Mg.

  12. [Effectiveness of incorporating a quality management system].

    PubMed

    Seki, Akira; Hankins, Raleigh W; Miya, Tetsumasa

    2010-01-01

    In 2003, the ISO 15189 international standardization program on the quality and competence of the clinical reference laboratory was introduced. To date, 46 facilities have committed themselves to providing a higher level of medical service by incorporating a quality management system (QMS) and acquiring accreditation. QMS is defined as "setting up a policy and goals pertaining to quality, and adopting an appropriate system," and is a scheme that includes all managerial and technical factors that can affect test results. Regarding the Health Sciences Research Institute Group, 4 facilities have previously received the accreditation described above, but in the process of implementing the QMS, a number of problems have been identified. Here, we report on the effectiveness of adopting such a QMS based on the results of employee questionnaires, internal audits, customer complaint analyses, and external audits by the Japan Accreditation Board for Conformity Assessment (JAB), the official inspection body for accreditation. PMID:20169949

  13. Experimental and numerical investigation into the joule heating effect for electrokinetically driven microfluidic chips utilizing total internal reflection fluorescence microscopy

    Microsoft Academic Search

    Lung-Ming Fu; Jing-Hui Wang; Wen-Bo Luo; Che-Hsin Lin

    2009-01-01

    This paper presents a detection scheme for analyzing the temperature distribution nearby the channel wall in a microfluidic\\u000a chip utilizing a temperature-dependent fluorescence dye. An advanced optical microscope system—total internal reflection fluorescence\\u000a microscope (TIRFM) is used for measuring the temperature distribution on the channel wall at the point of electroosmotic flow\\u000a in an electrokinetically driven microfluidic chip. In order to

  14. Electrokinetic Microstrirring to Enhance Immunoassays

    NASA Astrophysics Data System (ADS)

    Feldman, Hope; Sigurdson, Marin; Meinhart, Carl

    2006-11-01

    Electrokinetic microstirring is used to improve the sensitivity of microfluidic heterogeneous immuno-sensors by enhancing the transport in diffusion-limited reactions. The AC electrokinetic force, Electrothermal Flow, is exploited to create a circular stirring fluid motion, thereby providing more binding opportunities between suspended and wall-immobilized molecules. This process can significantly reduce test times, important for both field-portable biosensors and for lab-based assays. A 2-D numerical simulation model is used to predict the effect of electrothermal flow on a heterogeneous immunoassay resulting from an AC potential applied to two parallel electrodes. The binding is increased by a factor of 7 for an applied voltage of 10 Vrms. The effect was investigated experimentally using a high affinity biotin-streptavidin reaction. Microstirred reaction rates were compared with passive reactions. The measurements show on average an order of magnitude increase in binding between immobilized biotin and fluorescently-labeled streptavidin after 5 minutes. Therefore, this technique shows significant promise for reducing incubation time and enhancing the sensitivity of immunoassays.

  15. Integrated Electrokinetics-Adsorption Remediation of Saline-Sodic Soils: Effects of Voltage Gradient and Contaminant Concentration on Soil Electrical Conductivity

    PubMed Central

    Essa, Mohammed Hussain; Mu'azu, Nuhu Dalhat

    2013-01-01

    In this study, an integrated in situ remediation technique which couples electrokinetics with adsorption, using locally produced granular activated carbon from date palm pits in the treatment zones that are installed directly to bracket the contaminated soils at bench-scale, is investigated. Natural saline-sodic clay soil, spiked with contaminant mixture (kerosene, phenol, Cr, Cd, Cu, Zn, Pb, and Hg), was used in this study to investigate the effects of voltage gradient, initial contaminant concentration, and polarity reversal rate on the soil electrical conductivity. Box-Behnken Design (BBD) was used for the experimental design and response surface methodology (RSM) was employed to model, optimize, and interpret the results obtained using Design-Expert version 8 platform. The total number of experiments conducted was 15 with voltage gradient, polarity reversal rate, and initial contaminant concentration as variables. The main target response discussed in this paper is the soil electrical conductivity due to its importance in electrokinetic remediation process. Responses obtained were fitted to quadratic models whose R2 ranges from 84.66% to 99.19% with insignificant lack of fit in each case. Among the investigated factors, voltage gradient and initial contaminant concentration were found to be the most significant influential factors. PMID:24459439

  16. Electrokinetic transport of a fine cylindrical particle through a pore

    SciTech Connect

    Papadopoulos, K.D.; SenGupta, A.K. [Tulane Univ., New Orleans, LA (United States). Dept. of Chemical Engineering

    1994-12-31

    An analytical expression is developed for the electrokinetic velocity of a cylindrical particle in a host pore. In deriving this electrokinetic transport model, it is assumed that both the particle and the pore wall bear surface charges, and that the ionic strength of the suspending electrolyte is small. As a result, the particle velocity in the pore is not only influenced by the hydrodynamic effect arising from close proximity of the pre wall and the particle, but may also be affected by the electrical double layer interaction between the two surfaces. The effect of particle-pre double layer interaction on electrokinetic particle transport is examined under conditions of either constant surface potentials or constant surface charges. The results of this study may provide useful information in the design of processes such as electrokinetic deposition of particles in porous substrates, electrofiltration, electrochemical soil remediation etc.

  17. Electrokinetic mixing in microfluidic systems

    Microsoft Academic Search

    Chih-Chang Chang; Ruey-Jen Yang

    2007-01-01

    The applications of electrokinetics in the development of microfluidic devices have been widely attractive in the past decade. Electrokinetic devices generally\\u000a require no external mechanical moving parts and can be made portable by replacing the power supply by small battery. Therefore,\\u000a electrokinetic-based microfluidic systems can serve as a viable tool in creating a lab-on-a-chip (LOC) or micro-total analysis\\u000a system (?TAS)

  18. Effect of total organic carbon content and structure on the electrokinetic behavior of organoclay suspensions

    Microsoft Academic Search

    B. Bate; S. E. Burns

    2010-01-01

    This experimental investigation measured the zeta potential of the clay mineral, montmorillonite, which was modified with six different quaternary ammonium cations. The organic cations were chosen to quantify the effect of cation functional groups, including chain length and cation size, on the resulting zeta potential; each of the six cations were exchanged onto the clay surface at three levels of

  19. Electrode kinetic and electro-kinetic effects in electroosmotic dewatering of clay suspensions

    SciTech Connect

    Vijh, A.K. [Inst. de Recherche d`Hydro-Quebec, Varennes, Quebec (Canada)

    1997-05-01

    Lockhart`s remarks on the author`s previous interpretation of the electrochemical aspects of the electroosmotic dewatering (EOD) of clay suspensions are analyzed to provide some further clarification. Based on Lockhart`s excellent work, the authors put forward here novel electrochemical interpretations of some features of the following experimental observations: (1) Galvani dewatering; (2) the dewatering efficiency; and (3) high voltage needed for dewatering Al-kaolinite and aluminum electrode effect.

  20. Colloidal particle deposition from electrokinetic flow in a microfluidic channel.

    PubMed

    Unni, Harikrishnan Narayanan; Yang, Chun

    2009-03-01

    This study reports a theoretical and experimental study on the irreversible deposition of colloidal particles from electrokinetic microfluidic flow. The electrokinetic particle transport model presented in this study is based on the stochastic Langevin equation, incorporating the electrical, hydrodynamic, Derjaguin-Landau-Verwey-Overbeek colloidal interactions and random Brownian motion of colloidal particles. Brownian dynamics simulation is used to compute the particle deposition in terms of the surface coverage. Direct videomicroscopic observation using the parallel-plate flow cell technique is employed to determine the deposition kinetics of polystyrene latex particles in NaCl electrolytes. The theoretical predictions are compared with experimental results, and a reasonable agreement is found. PMID:19260008

  1. Electrokinetic geosynthetics in hydraulic applications

    Microsoft Academic Search

    Colin J. F. P. Jones; John Lamont-Black; Stephanie Glendinning

    2011-01-01

    In use most geosynthetics play a passive role. New applications for geosynthetics have been identified if they can provide an active role, initiating biological, chemical or physical change to the matrix in which it is installed as well as providing the established functions. This can be achieved by combining the electrokinetic phenomena of electro-osmosis, electrophoresis and associated electrokinetic functions such

  2. ELECTROKINETICS, INC. INSITU BIO REMEDIATION BY ELECTROKINETIC INJECTION EMERGING TECHNOLOGY SUMMARY

    EPA Science Inventory

    Electrokinetics, Inc. through a cooperative agreement with USEPA's NRMRL conducted a laboratory evaluation of electrokinetic transport as a means to enhance in-situ bioremediation of trichloroethene (TCE). Four critical aspects of enhancing bioremediation by electrokinetic inject...

  3. Mass transport in a porous microchannel for non-Newtonian fluid with electrokinetic effects.

    PubMed

    Mondal, Sourav; De, Sirshendu

    2013-03-01

    Quantification of mass transfer in porous microchannel is of paramount importance in several applications. Transport of neutral solute in presence of convective-diffusive EOF having non-Newtonian rheology, in a porous microchannel was presented in this article. The governing mass transfer equation coupled with velocity field was solved along with associated boundary conditions using a similarity solution method. An analytical solution of mass transfer coefficient and hence, Sherwood number were derived from first principles. The corresponding effects of assisting and opposing pressure-driven flow and EOF were also analyzed. The influence of wall permeation, double-layer thickness, rheology, etc. on the mass transfer was also investigated. Permeation at the wall enhanced the mass transfer coefficient more than five times compared to impervious conduit in case of pressure-driven flow assisting the EOF at higher values of ?h. Shear thinning fluid exhibited more enhancement of Sherwood number in presence of permeation compared to shear thickening one. The phenomenon of stagnation was observed at a particular ?h (?2.5) in case of EOF opposing the pressure-driven flow. This study provided a direct quantification of transport of a neutral solute in case of transdermal drug delivery, transport of drugs from blood to target region, etc. PMID:23192435

  4. Band-broadening suppressed effect in long turned geometry channel and high-sensitive analysis of DNA sample by using floating electrokinetic supercharging on a microchip

    PubMed Central

    Xu, Zhongqi; Murata, Kenji; Arai, Akihiro; Hirokawa, Takeshi

    2010-01-01

    A featured microchip owning three big reservoirs and long turned geometry channel was designed to improve the detection limit of DNA fragments by using floating electrokinetic supercharging (FEKS) method. The novel design matches the FEKS preconcentration needs of a large sample volume introduction with electrokinetic injection (EKI), as well as long duration of isotachophoresis (ITP) process to enrich low concentration sample. In the curved channel [?45.6 mm long between port 1 (P1) and the intersection point of two channels], EKI and ITP were performed while the side port 3 (P3) was electrically floated. The turn-induced band broadening with or without ITP process was investigated by a computer simulation (using CFD-ACE+ software) when the analytes traveling through the U-shaped geometry. It was found that the channel curvature determined the extent of band broadening, however, which could be effectively eliminated by the way of ITP. After the ITP-stacked zones passed the intersection point from P1, they were rapidly destacked for separation and detection from ITP to zone electrophoresis by using leading ions from P3. The FEKS carried on the novel chip successfully contributed to higher sensitivities of DNA fragments in comparison with our previous results realized on either a single channel or a cross microchip. The analysis of low concentration 50 bp DNA step ladders (0.23 ?g?ml after 1500-fold diluted) was achieved with normal UV detection at 260 nm. The obtained limit of detections (LODs) were on average 100 times better than using conventional pinched injection, down to several ng?ml for individual DNA fragment. PMID:20644677

  5. Competition between Dukhin's and Rubinstein's electrokinetic modes

    NASA Astrophysics Data System (ADS)

    Chang, H.-C.; Demekhin, E. A.; Shelistov, V. S.

    2012-10-01

    The combined effect of two modes of electroconvection, i.e., (a) the electro-osmotic flow of the second kind induced by a curved membrane surface and (b) electrokinetic instability, is studied numerically. Both physical mechanisms are responsible for electric current enhancement to the surface, and these modes are strongly nonlinearly coupled. For the limiting regimes, their resonant interaction near the threshold of instability with a corresponding resonantly amplified current enhancement is found. For the overlimiting regimes, inside the unstable region, their interaction becomes more complex with negative “sideband” and positive “subharmonic” resonant interactions. Wall corrugation can still be in resonance with the unstable modes. At some wave numbers of corrugation, these two mechanisms compete and electrokinetic instability can even be completely suppressed by the wall corrugation.

  6. Electrokinetic extraction of chromate from unsaturated soils

    SciTech Connect

    Mattson, E.D. [SAT-UNSAT, Inc., Albuquerque, NM (United States); Lindgren, E.R. [Sandia National Labs., Albuquerque, NM (United States)

    1993-11-01

    Heavy-metal contamination of soil and groundwater is a widespread problem in industrial nations. Remediation by excavation of such sites may not be cost effective or politically acceptable. Electrokinetic remediation is one possible remediation technique for in situ removal of such contaminants from unsaturated soils. Previous papers discussing the work performed by researchers at Sandia National Laboratories (SNL) and Sat-Unsat, Inc. (SUI) (Lindgren et al., 1991, 1992, 1993) focused on the transport of contaminants and dyes by electrokinetics in unsaturated soils. These experiments were conducted with graphite electrodes with no extraction system. As the contaminants migrated through the soil, they increased in concentration at the electrode creating a diffusion flux in the opposite direction. This paper discusses a technique to remove the contaminants from unsaturated soils once they have reached an electrode.

  7. Incorporating Allee effects into reintroduction strategies

    Microsoft Academic Search

    Doug P. Armstrong; Heiko U. Wittmer

    Allee effects, the reduction of vital rates at low population densities, can occur through several mechanisms, all of which\\u000a potentially apply to reintroduced populations. Reintroduced populations are initially at low densities, hence Allee effects\\u000a can potentially lead to reintroduction failure despite habitat quality being sufficient to allow long-term persistence if\\u000a the population survived the establishment phase. The probability of such

  8. Electrokinetic transport in microchannels with random roughness

    SciTech Connect

    Wang, Moran [Los Alamos National Laboratory; Kang, Qinjun [Los Alamos National Laboratory

    2008-01-01

    We present a numerical framework to model the electrokinetic transport in microchannels with random roughness. The three-dimensional microstructure of the rough channel is generated by a random generation-growth method with three statistical parameters to control the number density, the total volume fraction, and the anisotropy characteristics of roughness elements. The governing equations for the electrokinetic transport are solved by a high-efficiency lattice Poisson?Boltzmann method in complex geometries. The effects from the geometric characteristics of roughness on the electrokinetic transport in microchannels are therefore modeled and analyzed. For a given total roughness volume fraction, a higher number density leads to a lower fluctuation because of the random factors. The electroosmotic flow rate increases with the roughness number density nearly logarithmically for a given volume fraction of roughness but decreases with the volume fraction for a given roughness number density. When both the volume fraction and the number density of roughness are given, the electroosmotic flow rate is enhanced by the increase of the characteristic length along the external electric field direction but is reduced by that in the direction across the channel. For a given microstructure of the rough microchannel, the electroosmotic flow rate decreases with the Debye length. It is found that the shape resistance of roughness is responsible for the flow rate reduction in the rough channel compared to the smooth channel even for very thin double layers, and hence plays an important role in microchannel electroosmotic flows.

  9. Antibacterial effect of composite incorporating Triclosan against Streptococcus mutans.

    PubMed

    Imazato, S; Torii, M; Tsuchitani, Y

    1995-12-01

    It has been shown that composite incorporating the antibacterial agent Triclosan (Irgasan DP 300, which is sparingly soluble in water, inhibited in vitro plaque formation by Streptococcus mutans, although the release of the agent was much less than the minimum inhibitory concentration for the bacterium. In this study, the inhibitory effect of the composite incorporating 1% Triclosan against growth and adherence of S. mutans was investigated. S. mutans was inoculated on the surface of a specimen made of control or Triclosan-incorporated composite and the number of bacteria was compared after 3, 6, 12 and 24 hr of incubation. The adherence of S. mutans to the control and experimental composite, with or without saliva treatment, was also examined by scanning electron microscopy. The composite incorporating Triclosan demonstrated significant inhibition of growth of S. mutans after 6, 12 and 24 hr of incubation. Adherence of S. mutans to the Triclosan-incorporated composite was less compared with control for both non-treated and saliva-treated specimens. It is concluded that the antiplaque effect of composite incorporating Triclosan depends upon its ability to inhibit bacterial growth and adherence, and Triclosan-incorporated composite is able to exhibit the antibacterial activity even after being treated with saliva. PMID:9206462

  10. Induced-charge electrokinetic phenomena

    E-print Network

    Bazant, Martin Z.

    We give a general, physical description of “induced-charge electro-osmosis” (ICEO), the nonlinear electrokinetic slip at a polarizable surface, in the context of some new techniques for microfluidic pumping and mixing. ...

  11. Simulation of mixing depths incorporating the urban heat island effect

    Microsoft Academic Search

    Suhail M. Khan; Rod W. Simpson

    2001-01-01

    The main objective of this paper was to establish the effect of anthropogenic heat flux on the formation of mixing depth specially in urban areas. In this study an energy balance mixing depth model was developed for the simulation of mixing depth incorporating the heat island effect. To demonstrate the effect of heat island, mixing depths were simulated under two

  12. Electrokinetic remediation prefield test methods

    NASA Technical Reports Server (NTRS)

    Hodko, Dalibor (Inventor)

    2000-01-01

    Methods for determining the parameters critical in designing an electrokinetic soil remediation process including electrode well spacing, operating current/voltage, electroosmotic flow rate, electrode well wall design, and amount of buffering or neutralizing solution needed in the electrode wells at operating conditions are disclosed These methods are preferably performed prior to initiating a full scale electrokinetic remediation process in order to obtain efficient remediation of the contaminants.

  13. dc electrokinetic transport of cylindrical cells in straight microchannels

    PubMed Central

    Ai, Ye; Beskok, Ali; Gauthier, David T.; Joo, Sang W.; Qian, Shizhi

    2009-01-01

    Electrokinetic transport of cylindrical cells under dc electric fields in a straight microfluidic channel is experimentally and numerically investigated with emphasis on the dielectrophoretic (DEP) effect on their orientation variations. A two-dimensional multiphysics model, composed of the Navier–Stokes equations for the fluid flow and the Laplace equation for the electric potential defined in an arbitrary Lagrangian–Eulerian framework, is employed to capture the transient electrokinetic motion of cylindrical cells. The numerical predictions of the particle transport are in quantitative agreement with the obtained experimental results, suggesting that the DEP effect should be taken into account to study the electrokinetic transport of cylindrical particles even in a straight microchannel with uniform cross-sectional area. A comprehensive parametric study indicates that cylindrical particles would experience an oscillatory motion under low electric fields. However, they are aligned with their longest axis parallel to the imposed electric field under high electric fields due to the induced DEP effect. PMID:20216972

  14. Numerical simulation of electrokinetically driven micro flows 

    E-print Network

    Hahm, Jungyoon

    2005-11-01

    Spectral element based numerical solvers are developed to simulate electrokinetically driven flows for micro-fluidic applications. Based on these numerical solvers, basic phenomena and devices for electrokinetic applications in micro and nano flows...

  15. Numerical simulation of electrokinetically driven micro flows

    E-print Network

    Hahm, Jungyoon

    2005-11-01

    Spectral element based numerical solvers are developed to simulate electrokinetically driven flows for micro-fluidic applications. Based on these numerical solvers, basic phenomena and devices for electrokinetic applications in micro and nano flows...

  16. Estimation of electrokinetic and hydrodynamic global properties of relevant amyloid-beta peptides through the modeling of their effective electrophoretic mobilities and analysis of their propensities to aggregation.

    PubMed

    Deiber, Julio A; Piaggio, Maria V; Peirotti, Marta B

    2014-09-01

    Neuronal activity loss may be due to toxicity caused by amyloid-beta peptides forming soluble oligomers. Here amyloid-beta peptides (1-42, 1-40, 1-39, 1-38, and 1-37) are characterized through the modeling of their experimental effective electrophoretic mobilities determined by a capillary zone electrophoresis method as reported in the literature. The resulting electrokinetic and hydrodynamic global properties are used to evaluate amyloid-beta peptide propensities to aggregation through pair particles interaction potentials and Brownian aggregation kinetic theories. Two background electrolytes are considered at 25°C, one for pH 9 and ionic strength I = 40 mM (aggregation is inhibited through NH4OH) the other for pH 10 and I = 100 mM (without NH4OH). Physical explanations of peptide oligomerization mechanisms are provided. The effect of hydration, electrostatic, and dispersion forces in the amyloidogenic process of amyloid-beta peptides (1-40 and 1-42) are quantitatively presented. The interplay among effective charge number, hydration, and conformation of chains is described. It is shown that amyloid-beta peptides (1-40 and 1-42) at pH 10, I = 100 mM and 25°C, may form soluble oligomers, mainly of order 2 and 4, after an incubation of 48 h, which at higher times evolve and end up in complex structures (protofibrils and fibrils) found in plaques associated with Alzheimer's disease. PMID:24975363

  17. Photovoltaic Powered Electrokinetic Restoration of Saline Soil

    Microsoft Academic Search

    Do-Hyung Kim; Ji-Min Jung; Sung-Ung Jo; Woo-Seung Kim; Kitae Baek

    2012-01-01

    Electrokinetic techniques are currently being explored as a means of extracting or removing contaminants from soils, sediments, and sludge. However, energy costs account for 25% of total operation costs. In this study, we investigated the efficiency of conventional electrokinetic and photovoltaic powered electrokinetic systems for the removal of salts from saline agricultural soils. We tested four different potentiostatic systems: a

  18. Acoustically and Electrokinetically Driven Transport in Microfluidic Devices

    NASA Astrophysics Data System (ADS)

    Sayar, Ersin

    Electrokinetically driven flows are widely employed as a primary method for liquid pumping in micro-electromechanical systems. Mixing of analytes and reagents is limited in microfluidic devices due to the low Reynolds number of the flows. Acoustic excitations have recently been suggested to promote mixing in the microscale flow systems. Electrokinetic flows through straight microchannels were investigated using the Poisson-Boltzmann and Nernst-Planck models. The acoustic wave/fluid flow interactions in a microchannel were investigated via the development of two and three-dimensional dynamic predictive models for flows with field couplings of the electrical, mechanical and fluid flow quantities. The effectiveness and applicability of electrokinetic augmentation in flexural plate wave micropumps for enhanced capabilities were explored. The proposed concept can be exploited to integrate micropumps into complex microfluidic chips improving the portability of micro-total-analysis systems along with the capabilities of actively controlling acoustics and electrokinetics for micro-mixer applications. Acoustically excited flows in microchannels consisting of flexural plate wave devices and thin film resonators were considered. Compressible flow fields were considered to accommodate the acoustic excitations produced by a vibrating wall. The velocity and pressure profiles for different parameters including frequency, channel height, wave amplitude and length were investigated. Coupled electrokinetics and acoustics cases were investigated while the electric field intensity of the electrokinetic body forces and actuation frequency of acoustic excitations were varied. Multifield analysis of a piezoelectrically actuated valveless micropump was also presented. The effect of voltage and frequency on membrane deflection and flow rate were investigated. Detailed fluid/solid deformation coupled simulations of piezoelectric valveless micropump have been conducted to predict the generated time averaged flow rates. Developed coupled solid and fluid mechanics models can be utilized to integrate flow-through sensors with microfluidic chips.

  19. Friction models incorporating thermal effects in highly precision actuators

    NASA Astrophysics Data System (ADS)

    Li, J. W.; Chen, X. B.; An, Q.; Tu, S. D.; Zhang, W. J.

    2009-04-01

    This paper presents two models based on the LuGre model for friction with consideration of thermal effects. In Model I, parameters in the LuGre model are considered as temperature dependent. In Model II, parameters in the LuGre model are considered as temperature independent; while a temperature-dependent function is added to the temperature-independent LuGre model. Both models are experimentally evaluated, which shows that both can effectively incorporate thermal effects but Model II has better accuracy. Since these models are developed in the context of the motion system, they should be readily incorporated in motion control algorithms for effective control of motion systems with friction if temperature rise is significant in these systems.

  20. Electrokinetic high pressure hydraulic system

    DOEpatents

    Paul, Phillip H. (Livermore, CA); Rakestraw, David J. (Fremont, CA)

    2000-01-01

    A compact high pressure hydraulic pump having no moving mechanical parts for converting electric potential to hydraulic force. The electrokinetic pump, which can generate hydraulic pressures greater than 2500 psi, can be employed to compress a fluid, either liquid or gas, and manipulate fluid flow. The pump is particularly useful for capillary-base systems. By combining the electrokinetic pump with a housing having chambers separated by a flexible member, fluid flow, including high pressure fluids, is controlled by the application of an electric potential, that can vary with time.

  1. Electrokinetic-enhanced bioremediation of organic contaminants: a review of processes and environmental applications.

    PubMed

    Gill, R T; Harbottle, M J; Smith, J W N; Thornton, S F

    2014-07-01

    There is current interest in finding sustainable remediation technologies for the removal of contaminants from soil and groundwater. This review focuses on the combination of electrokinetics, the use of an electric potential to move organic and inorganic compounds, or charged particles/organisms in the subsurface independent of hydraulic conductivity; and bioremediation, the destruction of organic contaminants or attenuation of inorganic compounds by the activity of microorganisms in situ or ex situ. The objective of the review is to examine the state of knowledge on electrokinetic bioremediation and critically evaluate factors which affect the up-scaling of laboratory and bench-scale research to field-scale application. It discusses the mechanisms of electrokinetic bioremediation in the subsurface environment at different micro and macroscales, the influence of environmental processes on electrokinetic phenomena and the design options available for application to the field scale. The review also presents results from a modelling exercise to illustrate the effectiveness of electrokinetics on the supply electron acceptors to a plume scale scenario where these are limiting. Current research needs include analysis of electrokinetic bioremediation in more representative environmental settings, such as those in physically heterogeneous systems in order to gain a greater understanding of the controlling mechanisms on both electrokinetics and bioremediation in those scenarios. PMID:24875868

  2. Catalytically induced electrokinetics for motors and micropumps.

    PubMed

    Paxton, Walter F; Baker, Paul T; Kline, Timothy R; Wang, Yang; Mallouk, Thomas E; Sen, Ayusman

    2006-11-22

    We have explored the role of electrokinetics in the spontaneous motion of platinum-gold nanorods suspended in hydrogen peroxide (H2O2) solutions that may arise from the bimetallic electrochemical decomposition of H2O2. The electrochemical decomposition pathway was confirmed by measuring the steady-state short-circuit current between platinum and gold interdigitated microelectrodes (IMEs) in the presence of H2O2. The resulting ion flux from platinum to gold implies an electric field in the surrounding solution that can be estimated from Ohm's Law. This catalytically generated electric field could in principle bring about electrokinetic effects that scale with the Helmholtz-Smoluchowski equation. Accordingly, we observed a linear relationship between bimetallic rod speed and the resistivity of the bulk solution. Previous observations relating a decrease in speed to an increase in ethanol concentration can be explained in terms of a decrease in current density caused by the presence of ethanol. Furthermore, we found that the catalytically generated electric field in the solution near a Pt/Au IME in the presence of H2O2 is capable of inducing electroosmotic fluid flow that can be switched on and off externally. We demonstrate that the velocity of the fluid flow in the plane of the IME is a function of the electric field, whether catalytically generated or applied from an external current source. Our findings indicate that the motion of PtAu nanorods in H2O2 is primarily due to a catalytically induced electrokinetic phenomenon and that other mechanisms, such as those related to interfacial tension gradients, play at best a minor role. PMID:17105298

  3. Catalytically Induced Electrokinetics for Motors and Walter F. Paxton, Paul T. Baker, Timothy R. Kline, Yang Wang,

    E-print Network

    Catalytically Induced Electrokinetics for Motors and Micropumps Walter F. Paxton, Paul T. Baker microelectrodes (IMEs) in the presence of H2O2. The resulting ion flux from platinum to gold implies an electric electric field could in principle bring about electrokinetic effects that scale with the Helmholtz

  4. Nonlinear electrokinetics at large voltages

    E-print Network

    Bazant, Martin Z.

    The classical theory of electrokinetic phenomena assumes a dilute solution of point-like ions in chemical equilibrium with a surface whose double-layer voltage is of order the thermal voltage, kBT/e=25 mV. In nonlinear ...

  5. Electrokinetically pumped high pressure sprays

    DOEpatents

    Schoeniger, Joseph S. (Oakland, CA); Paul, Phillip H. (Livermore, CA); Schoeniger, Luke (Pittsford, NY)

    2005-11-01

    An electrokinetic pump capable of producing high pressure is combined with a nozzle having a submicron orifice to provide a high pressure spray device. Because of its small size, the device can be contained within medical devices such as an endoscope for delivering biological materials such as DNA, chemo therapeutic agents, or vaccines to tissues and cells.

  6. Electrokinetically pumped high pressure sprays

    DOEpatents

    Schoeniger, Joseph S. (Oakland, CA); Paul, Phillip H. (Livermore, CA); Schoeniger, Luke (Pittsford, NY)

    2002-01-01

    An electrokinetic pump capable of producing high pressure is combined with a nozzle having a submicron orifice to provide a high pressure spray device. Because of its small size, the device can be contained within medical devices such as an endoscope for delivering biological materials such as DNA, chemo therapeutic agents, or vaccines to tissues and cells.

  7. Immersed electrokinetic finite element method

    Microsoft Academic Search

    Yaling Liu; Ted Belytschko; Neelesh Patankar; Albert C. To; Adrian Kopacz; Jae-Hyun Chung

    2007-01-01

    SUMMARY A new method is proposed for modelling the electrokinetic-induced mechanical motion of particles in a fluid domain under an applied electric field. In this method, independent solid meshes move in a fixed background field mesh that models the fluid and the electric field. This simple strategy removes the need for expensive mesh updates. Furthermore, the reproducing kernel particle functions

  8. Electrokinetic confinement of axonal growth for dynamically configurable neural networks

    PubMed Central

    Honegger, Thibault; Scott, Mark A.; Yanik, Mehmet F.; Voldman, Joel

    2013-01-01

    Axons in the developing nervous system are directed via guidance cues, whose expression varies both spatially and temporally, to create functional neural circuits. Existing methods to create patterns of neural connectivity in vitro use only static geometries, and are unable to dynamically alter the guidance cues imparted on the cells. We introduce the use of AC electrokinetics to dynamically control axonal growth in cultured rat hippocampal neurons. We find that the application of modest voltages at frequencies on the order of 105 Hz can cause developing axons to be stopped adjacent to the electrodes while axons away from the electric fields exhibit uninhibited growth. By switching electrodes on or off, we can reversibly inhibit or permit axon passage across the electrodes. Our models suggest that dielectrophoresis is the causative AC electrokinetic effect. We make use of our dynamic control over axon elongation to create an axon-diode via an axon-lock system that consists of a pair of electrode `gates' that either permit or prevent axons from passing through. Finally, we developed a neural circuit consisting of three populations of neurons, separated by three axon-locks to demonstrate the assembly of a functional, engineered neural network. Action potential recordings demonstrate that the AC electrokinetic effect does not harm axons, and Ca2+ imaging demonstrated the unidirectional nature of the synaptic connections. AC electrokinetic confinement of axonal growth has potential for creating configurable, directional neural networks. PMID:23314575

  9. Electrokinetic confinement of axonal growth for dynamically configurable neural networks.

    PubMed

    Honegger, Thibault; Scott, Mark A; Yanik, Mehmet F; Voldman, Joel

    2013-02-21

    Axons in the developing nervous system are directed via guidance cues, whose expression varies both spatially and temporally, to create functional neural circuits. Existing methods to create patterns of neural connectivity in vitro use only static geometries, and are unable to dynamically alter the guidance cues imparted on the cells. We introduce the use of AC electrokinetics to dynamically control axonal growth in cultured rat hippocampal neurons. We find that the application of modest voltages at frequencies on the order of 10(5) Hz can cause developing axons to be stopped adjacent to the electrodes while axons away from the electric fields exhibit uninhibited growth. By switching electrodes on or off, we can reversibly inhibit or permit axon passage across the electrodes. Our models suggest that dielectrophoresis is the causative AC electrokinetic effect. We make use of our dynamic control over axon elongation to create an axon-diode via an axon-lock system that consists of a pair of electrode 'gates' that either permit or prevent axons from passing through. Finally, we developed a neural circuit consisting of three populations of neurons, separated by three axon-locks to demonstrate the assembly of a functional, engineered neural network. Action potential recordings demonstrate that the AC electrokinetic effect does not harm axons, and Ca(2+) imaging demonstrated the unidirectional nature of the synaptic connections. AC electrokinetic confinement of axonal growth has potential for creating configurable, directional neural networks. PMID:23314575

  10. Electrokinetics of Correlated Electrolytes and Ionic Liquids

    NASA Astrophysics Data System (ADS)

    Storey, Brian; Bazant, Martin

    2011-11-01

    Perhaps the most basic assumption of classical electrokinetic theory is the mean-field approximation, where the each ion feels only the electric field produced by the mean charge density (via Poisson's equation) rather than the fluctuating Coulomb forces with individual neighbors. Here, we present a simple continuum model for electrostatic correlations between finite-sized ions, which leads to a 4th order modified Poisson equation, convenient for the analysis of electrokinetic phenomena. When the mean-field approximation breaks down, e.g. due to large ion concentrations, large ion valences, and/or nanoscale confinement, the zeta potential loses its significance, and the model predicts that electro-osmotic flows are typically reduced - or even reversed - by correlation effects, compared to the prediction of the Helmholtz-Smoluchowski formula. This may help to explain the over-prediction of induced-charge electro-osmotic flows by classical models. An interesting limit of the model describes electro-osmosis in solvent-free ionic liquids and molten salts, which may be important in energy storage and electroactuation applications.

  11. Experiments on Nonlinear Electrokinetic Pumps in Microfluidics

    NASA Astrophysics Data System (ADS)

    Urbanski, John Paul; Thorsen, Todd; Levitan, Jeremy A.; Bazant, Martin Z.

    2006-03-01

    Nonlinear electrokinetic pumps are attractive in the development of portable and flexible microfluidic analysis systems, since they operate without moving parts using low (battery powered) alternating potentials. Since the discovery of AC electro-osmosis (ACEO) in the late 1990s, there has been much work in designing and building two-dimensional, periodic micro-electrode geometries, which exploit broken symmetry to rectify AC forcing and produce steaming flow over a surface. Building on this work, we exploit more general principles of induced-charge electro-osmosis (ICEO) in three-dimensional electrode geometries to enhance pumping in microfluidic devices. Our fabrication efforts are guided by theoretical analysis and simulations using the standard low-voltage theory, which, in some cases, predict flow rates faster than existing planar ACEO pumps by an order of magnitude (for the same voltage and feature size). We test various microfabricated pump geometries in a microfluidic loop following the methodology of Studer et al (2004). We are also measuring the strong effect of solution chemistry (e.g. ion valence and concentration) on ICEO flow to guide further developments in the theory of nonlinear electrokinetics.

  12. Effect of aliphatic alcohols as mobile phase modifiers on separation of phenylurea and phenoxyalkyl acid herbicides by micellar electrokinetic capillary chromatography

    Microsoft Academic Search

    Adriana Farran; Santiago Ruiz

    1995-01-01

    The rapid and single separation of a mixture of neutral and ionic herbicides, five phenylurea (diuron, fenuron, linuron, monolinuron and monuron) and four phenoxyalkyl acids (dichlorprop, 2,4-D, 2,4,5-T and 2,4-DB) was achieved by micellar electrokinetic capillary chromatography (MECC) after different aliphatic alcohols (1-heptanol, 1-hexanol, 1-pentanol, 1-butanol and methanol) were added to a phosphate buffer (0.02 M) containing 0.05 M sodium

  13. Nonlinear electrokinetics and "superfast" electrophoresis.

    PubMed

    Ben, Yuxing; Demekhin, Eugene A; Chang, Hsueh-Chia

    2004-08-15

    Nonlinear and nonequilibrium electrophoresis of spherical particles of radius a is shown to be possible when the solid surface allows field or current penetration. At low particle Peclet numbers, transient capacitative charging occurs until the surface polarization completely screens the external field. For a DC applied field [see text], the resulting electrokinetic velocity reaches Dukhin's maximum value of [formula: see text], where [see text] and mu are the liquid permittivity and viscosity. At high Peclet numbers, electroosmotic convection of the electroneutral bulk stops the transient charging before complete field-line exclusion. For an ion-selective and conducting spherical granule, the polarization is then determined by the steady-state Ohmic current driven by the penetrated external field. The high-Peclet electrokinetic velocity is lower, diffusivity-dependent and scales as [see text]. PMID:15271577

  14. Electrokinetic high pressure hydraulic system

    DOEpatents

    Paul, Phillip H.; Rakestraw, David J.; Arnold, Don W.; Hencken, Kenneth R.; Schoeniger, Joseph S.; Neyer, David W.

    2003-06-03

    An electrokinetic high pressure hydraulic pump for manipulating fluids in capillary-based system. The pump uses electro-osmotic flow to provide a high pressure hydraulic system, having no moving mechanical parts, for pumping and/or compressing fluids, for providing valve means and means for opening and closing valves, for controlling fluid flow rate, and manipulating fluid flow generally and in capillary-based systems (microsystems), in particular. The compact nature of the inventive high pressure hydraulic pump provides the ability to construct a micro-scale or capillary-based HPLC system that fulfills the desire for small sample quantity, low solvent consumption, improved efficiency, the ability to run samples in parallel, and field portability. Control of pressure and solvent flow rate is achieved by controlling the voltage applied to an electrokinetic pump.

  15. Electrokinetic high pressure hydraulic system

    DOEpatents

    Paul, Phillip H. (Livermore, CA); Rakestraw, David J. (Fremont, CA); Arnold, Don W. (Livermore, CA); Hencken, Kenneth R. (Pleasanton, CA); Schoeniger, Joseph S. (Oakland, CA); Neyer, David W. (Castro Valley, CA)

    2001-01-01

    An electrokinetic high pressure hydraulic pump for manipulating fluids in capillary-based systems. The pump uses electro-osmotic flow to provide a high pressure hydraulic system, having no moving mechanical parts, for pumping and/or compressing fluids, for providing valve means and means for opening and closing valves, for controlling fluid flow rate, and manipulating fluid flow generally and in capillary-based systems (Microsystems), in particular. The compact nature of the inventive high pressure hydraulic pump provides the ability to construct a micro-scale or capillary-based HPLC system that fulfills the desire for small sample quantity, low solvent consumption, improved efficiency, the ability to run samples in parallel, and field portability. Control of pressure and solvent flow rate is achieved by controlling the voltage applied to an electrokinetic pump.

  16. `Designer' porous channels for electrokinetic injection and microfluidic manipulation

    NASA Astrophysics Data System (ADS)

    Squires, Todd; Narovlyansky, Max

    2005-03-01

    Microfabrication techniques allow effective `porous' media in microchannels to be designed with specified properties. In this talk, we present a general and intuitive framework for such systems. For electrokinetic phenomena, specifying the `pore' geometry is akin to effectively determining the dielectric constant. Pressure-driven systems, on the other hand, are even richer, since an effective permeability and volume fraction can be independently controlled. Furthermore, anisotropy can be deliberately designed into the channel properties, opening a range of possibilities for microfluidic applications. We present simple, intuitive examples to highlight the basic effect, and demonstrate how such ideas can be used for applications of practical interest, such as using electrokinetic injection to form sharp sample plugs for high-resolution separations. Both theoretical and experimental results will be presented.

  17. Electrokinetic dewatering of a phosphate clay

    Microsoft Academic Search

    J. Q. Shang; K. Y. Lo

    1997-01-01

    The principles of electrokinetic dewatering are: (1) electrophoresis, the movement of colloidal particles in a direct current electric field; (2) dielectrophoresis, the movement of colloidal particles in a non-uniform electric field; and (3) electro-osmosis, the water flow in porous media in a direct current electric field. Electrokinetic dewatering of a phosphate clay was investigated in an experimental program. The results

  18. REMOVAL OF RADIONUCLIDES BY ELECTROKINETIC SOIL PROCESSING

    EPA Science Inventory

    Electrokinetics promises to be an innovative treatment process for in-situ treatment of soils and groundwater contaminated with heavy metals and radionuclides. Electrokinetics refers to the movement of ionic liquids and charged particles relative to one another under the action ...

  19. Determination of allantoin in biofluids using micellar electrokinetic capillary chromatography

    Microsoft Academic Search

    Luwiza N Alfazema; Sian Howells; David Perrett

    1998-01-01

    A micellar electrokinetic chromatographic method is described for the determination and quantitation of allantoin, an end-product of purine metabolism in mammals that is applicable to biofluids of different mammal species and man. The method was optimised following a study on the effect of pH and sample preparation procedure. Final conditions were 30 mM sodium tetraborate, pH 9.5, 75 mM sodium

  20. Thermal analysis of electrokinetic remediation

    SciTech Connect

    Shapiro, A.P. [General Electric Corporate Research and Development, Schenectady, NY (United States); Schultz, D.S. [Dupont Central Research and Development, Newark, DE (United States)

    1995-12-31

    A mathematical model which predicts the thermal behavior of electrokinetic remediation is described. Three model simulations are summarized and compared to pilottest measurements. The model shows that constant applied current should lead to a relatively constant flow rate and decreasing power consumption, whereas constant voltage will lead to increasing electroosmotic flow and increasing power consumption. While steady-state thermal conditions were not reached in the 100-day pilot test, the constant current case simulations approach steady-state temperature distribution much sooner than constant voltage cases. Commonly used electric fields in laboratory experiments of about 100 V/m appear to cause excessive heating in field scale applications.

  1. Dielectrophoretic concentration of particles under electrokinetic flow

    DOEpatents

    Miles, Robin R.; Bettencourt, Kerry A.; Fuller, Christopher K.

    2004-09-07

    The use of dielectrophoresis to collect particles under the conditions of electrokinetically-driven flow. Dielectrophortic concentration of particles under electrokinetic flow is accomplished by interdigitated electrodes patterned on an inner surface of a microfluid channel, a DC voltage is applied across the ends to the channel, and an AC voltage is applied across the electrodes, and particles swept down the channel electrokinetically are trapped within the field established by the electrodes. The particles can be released when the voltage to the electrodes is released.

  2. Electro-kinetically triggered capillary switches

    NASA Astrophysics Data System (ADS)

    Vogel, Michael J.; Steen, Paul H.; Ehrhard, Peter

    2004-11-01

    A bistable system of liquid/gas interfaces is a potential capillary switch. On the sub-millimeter scale, where shape is determined primarily by surface tension, two coupled droplets (common pressure) provide a simple example of an energy landscape with two wells. For such a bistable system to become a switch, a trigger is needed to toggle back and forth between the two stable shapes. In this talk, we show that triggering can occur electro-kinetically by imposing a small voltage difference across an electro-osmotic pump placed between the droplets. The concept, design and construction of the electo-kinetic droplet switch (EKDS) will be described and its functionality will be demonstrated. The design is based on a model that accounts for both electro-osmosis and for the flow driven by capillary pressure differences between the droplet surfaces. Switching times for the EKDS predicted by the model are compared to observation. Fundamentally, the EKDS is an electro-mechanical transducer that can act as actuator or sensor. Applications that incorporate efficient actuation into lab-on-chip and other micro-fluidic platforms are envisioned.

  3. Electrokinetics of scalable, electric-field-assisted fabrication of vertically aligned carbon-nanotube/polymer composites

    NASA Astrophysics Data System (ADS)

    Castellano, Richard J.; Akin, Cevat; Giraldo, Gabriel; Kim, Sangil; Fornasiero, Francesco; Shan, Jerry W.

    2015-06-01

    Composite thin films incorporating vertically aligned carbon nanotubes (VACNTs) offer promise for a variety of applications where the vertical alignment of the CNTs is critical to meet performance requirements, e.g., highly permeable membranes, thermal interfaces, dry adhesives, and films with anisotropic electrical conductivity. However, current VACNT fabrication techniques are complex and difficult to scale up. Here, we describe a solution-based, electric-field-assisted approach as a cost-effective and scalable method to produce large-area VACNT composites. Multiwall-carbon nanotubes are dispersed in a polymeric matrix, aligned with an alternating-current (AC) electric field, and electrophoretically concentrated to one side of the thin film with a direct-current (DC) component to the electric field. This approach enables the fabrication of highly concentrated, individually aligned nanotube composites from suspensions of very dilute ( ? = 4 × 10 - 4 ) volume fraction. We experimentally investigate the basic electrokinetics of nanotube alignment under AC electric fields, and show that simple models can adequately predict the rate and degree of nanotube alignment using classical expressions for the induced dipole moment, hydrodynamic drag, and the effects of Brownian motion. The composite AC + DC field also introduces complex fluid motion associated with AC electro-osmosis and the electrochemistry of the fluid/electrode interface. We experimentally probe the electric-field parameters behind these electrokinetic phenomena, and demonstrate, with suitable choices of processing parameters, the ability to scalably produce large-area composites containing VACNTs at number densities up to 1010 nanotubes/cm2. This VACNT number density exceeds that of previous electric-field-fabricated composites by an order of magnitude, and the surface-area coverage of the 40 nm VACNTs is comparable to that of chemical-vapor-deposition-grown arrays of smaller-diameter nanotubes.

  4. Nonlinear electrokinetics at large voltages

    NASA Astrophysics Data System (ADS)

    Bazant, Martin Z.; Sabri Kilic, Mustafa; Storey, Brian D.; Ajdari, Armand

    2009-07-01

    The classical theory of electrokinetic phenomena assumes a dilute solution of point-like ions in chemical equilibrium with a surface whose double-layer voltage is of order the thermal voltage, kBT/e=25 mV. In nonlinear 'induced-charge' electrokinetic phenomena, such as ac electro-osmosis, several volts ?100kBT/e are applied to the double layer, and the theory breaks down and cannot explain many observed features. We argue that, under such a large voltage, counterions 'condense' near the surface, even for dilute bulk solutions. Based on simple models, we predict that the double-layer capacitance decreases and the electro-osmotic mobility saturates at large voltages, due to steric repulsion and increased viscosity of the condensed layer, respectively. The former suffices to explain observed high-frequency flow reversal in ac electro-osmosis; the latter leads to a salt concentration dependence of induced-charge flows comparable to experiments, although a complete theory is still lacking.

  5. Enhancing the Efficiency of Electrokinetic Remediation through Technology Integration

    NASA Astrophysics Data System (ADS)

    Zhang, M.; Komai, T.

    2009-12-01

    Remediation or cleanup of soils and groundwater polluted by heavy metals remains a challenge in the field of geo-environmental engineering. Many sites, like ore dressing plants, electroplating plants and battery factories may be polluted by heavy metals. In addition, some natural factors like metal deposits or abundant metal mines, hot springs and volcanic eruptions may also cause heavy metal pollutions. Unlike organic pollutants, heavy metals do not decay naturally, and active approaches to remediation are generally necessary. Although electrokinetic method is considered to be the only technique that is highly-perspective for in situ remediation of heavy metals, and numerous bench-scale studies as well as a few pilot scale experiments illustrated its applicability, this technique has not yet been widely used in practice due to the low efficiencies and/or unacceptable long remediation periods. To enhance the total efficiency of electrokinetic remediation, a systematic approach by integrating different technologies is proposed. This systematic approach includes 1) on-site quick mapping for screening out localized pollution areas, characterizing chemical composition of polluted soils, and for examining the progress of in situ remediation; 2) electrical resistivity tomography(ERT) or electrical resistivity imaging(ERI) for predicting geological structure and hydrogeological boundaries conditions of a polluted site, and for optimizing parameters like voltage and current density for an effective remediation; 3) the use of solar energy to increase flexibility in and applicability of electrokinetic technique; 4) combination with large scale modeling tests for a pertinent evaluation of the feasibility related to electrokinetic remediation for a given soil type taken from a specific polluted site; 5) combination with risk-assessment method to determine feasible cleanup levels; and 6) recovery of heavy metals deposited on electrode plates for possible use as resources. Feasibilities of the proposed systematic approach are illustrated through practical examinations.

  6. Experimental verification of Faradaic charging in ac electrokinetics.

    PubMed

    Ng, Wee Yang; Lam, Yee Cheong; Rodríguez, Isabel

    2009-01-01

    This paper investigates the phenomenon of Faradaic charging in ac electrokinetics. Faradaic reactions were suggested as a key effect responsible for the reversal of pumping direction in ac micropumps. However, this hypothesis has yet to be proven convincingly and directly. Here we present an ion detection strategy to determine the production of ions through Faradaic hydrolytic reactions originating from direct application of voltage to electrolytic solutions during ac electrokinetics. Experiments were performed with symmetrical planar electrodes aligned along a microfluidic channel. Fluorescein, a pH-dependent dye, was employed as the pH indicator for the detection of ion production. Images were captured for analysis at various voltage levels. From analyzing the fluorescence intensity and its distribution, it can be concluded that the production of ions from hydrolytic reactions takes place and increases with the ac voltage. The coefficient of deviation indicates a significant enhancement at ac voltage above 11 V(pp). Lastly, we demonstrate a strategy using dc-biased ac electrokinetics to achieve controllability in direction and magnitude of the net fluid flow in pumping application. PMID:19693340

  7. Incorporation of Landau-Pomeranchuk-Migdal effect and dielectric suppression effect in EGS5 code

    NASA Astrophysics Data System (ADS)

    Kirihara, Y.; Namito, Y.; Hirayama, H.

    2010-08-01

    We incorporated the Landau-Pomeranchuk-Migdal (LPM) effect and the dielectric suppression effect for bremsstrahlung and the LPM effect for pair production in the EGS5 code. To verify the validity of the EGS5 code with the LPM plus dielectric cross section for bremsstrahlung, we compared the bremsstrahlung spectrum calculated using this code with that obtained considering the LPM effect. The values calculated using the EGS5 code reproduced the experimental value of the LPM effect well.

  8. Electrokinetics as a Propellantless Propulsion Source

    NASA Astrophysics Data System (ADS)

    Valone, Thomas

    This is a review of the worthwhile, innovative theories and concepts in electrogravitics and electrokinetics that could yield tremendous technological and economic dividends in both investment dollars and potential applications for future generations. Electrogravitics is most commonly associated with the 1918 work by Professor Nipher followed by the 1928 British patent #300,311 of T. Townsend Brown, the 1952 Special Inquiry File #24-185 of the Office of Naval Research into the "Electro-Gravity Device of Townsend Brown" and two widely circulated 1956 Aviation Studies Ltd. Reports on "Electrogravitics Systems" and "The Gravitics Situation." By definition, electrogravitics historically has had a purported relationship to gravity or the object's mass, as well as the applied voltage. An analysis of the 90-year old science of electrogravitics (or electrogravity) necessarily includes an analysis of electrokinetics. Electrokinetics, on the other hand, is more commonly associated with many patents of T. Townsend Brown as well as Agnew Bahnson, starting with the 1960 US patent #2,949,550 entitled, "Electrokinetic Apparatus." Electrokinetics, which often involves a capacitor and dielectric, has virtually no relationship that can be connected with mass or gravity. The Army Research Lab has recently issued a report on electrokinetics, analyzing the force on an asymmetric capacitor, while NASA has received three patents on the same design topic. To successfully describe and predict the purported motion in the direction of the positive terminal of the capacitor, it is desirable to use the classical electrokinetic field and force equations for the specific geometry involved. This initial review also suggests directions for further confirming measurements. This paper also reviews the published electrokinetic experiments by the Army Research Lab by Bahder and Fazi, California State University at Fullerton work by Woodward and Mahood, Erwin Saxl, and others.

  9. Effective Incorporation of Biomarkers into Phase II Trials

    Microsoft Academic Search

    Lisa M. McShane; Sally Hunsberger; Alex A. Adjei; CCR FOCUS

    2009-01-01

    The incorporation of biomarkers into the drug development process will improve understanding of how new therapeutics workand allow for more accurate identification of patients who will benefit from those therapies. Strategically planned biomarker evaluations in phase II studies may allow for the design of more efficient phase III trials and better screening of therapeutics for entry into phase III development,

  10. Electrokinetic focusing and filtration of cells in a serpentine microchannel

    E-print Network

    Xuan, Xiangchun "Schwann"

    Electrokinetic focusing and filtration of cells in a serpentine microchannel Christopher Church,1 and numerically. A continuous electrokinetic filtration of E. coli cells from yeast cells was also demonstrated

  11. Electrokinetic properties of polymer colloids

    NASA Technical Reports Server (NTRS)

    Micale, F. J.; Fuenmayor, D. Y.

    1986-01-01

    The surface of polymer colloids, especially polystyrene latexes, were modified for the purpose of controlling the electrokinetic properties of the resulting colloids. Achievement required a knowledge of electrical double layer charging mechanism, as a function of the electrolyte conditions, at the polymer/water interface. The experimental approach is to control the recipe formulation in the emulsion polymerization process so as to systematically vary the strong acid group concentration on the surface of the polymer particles. The electrophoretic mobility of these model particles will then be measured as a function of surface group concentration and as a function of electrolyte concentration and type. An effort was also made to evaluate the electrophoretic mobility of polystyrene latexes made in space and to compare the results with latexes made on the ground.

  12. Electrokinetics of Polar Liquids in Contact with Non-Polar Surfaces

    E-print Network

    Lin, Chih-Hsiu; Chaudhury, Manoj K

    2014-01-01

    Zeta potentials of several polar protic (water, ethylene glycol, formamide) as well as polar aprotic (dimethyl sulfoxide) liquids were measured in contact with three non-polar surfaces using closed-cell electro-osmosis. The test surfaces were chemisorbed monolayers of alkyl siloxanes, fluoroalkyl siloxanes and polydimethylsiloxanes (PDMS) grafted on glass slides. All these liquids exhibited substantial electrokinetics in contact with the non-polar surfaces with these observations: the electrokinetic effect on the fluorocarbon-coated surface is the strongest; and on a PDMS grafted surface, the effect is the weakest. Even though these hygroscopic liquids contain small amounts of water, the current models of charging based on the adsorption of hydroxide ions at the interface or the dissociation of preexisting functionalities (e.g., silanol groups) appear to be insufficient to account for the various facets of the experimental observations. The results illustrate how ubiquitous the phenomenon of electro-kinetics ...

  13. Electrokinetic Focusing and Separation of Mammalian Cells in Conductive Biological Fluids

    PubMed Central

    Gao, Jian Gao; Riahi, Reza; Sin, Mandy L. Y.; Zhang, Shufeng; Wong, Pak Kin

    2014-01-01

    Active manipulation of cells, such as trapping, focusing, and isolation, is essential for various bioanalytical applications. Herein, we report a hybrid electrokinetic technique for manipulating mammalian cells in physiological fluids. This technique applies a combination of negative dielectrophoretic force and hydrodynamic drag force induced by electrohydrodynamics, which is effective in conductive biological fluids. With a three-electrode configuration, the stable equilibrium positions of cells can be adjusted for separation and focusing applications. Cancer cells and white blood cells can be positioned and isolated into specific locations in the microchannel under both static and dynamic flow conditions. To investigate the sensitivity of the hybrid electrokinetic process, AC voltage, frequency, and bias dependences of the cell velocity were studied systematically. The applicability of the hybrid electrokinetic technique for manipulating cells in physiological samples is demonstrated by continuous focusing human breast adenocarcinoma spiked in urine, buffy coats, and processed blood samples with 98% capture efficiency. PMID:22937529

  14. Electrokinetic acceleration of DNA hybridization in microsystems.

    PubMed

    Lei, Kin Fong; Wang, Yun-Hsiang; Chen, Huai-Yi; Sun, Jia-Hong; Cheng, Ji-Yen

    2015-06-01

    In this work, electrokinetic acceleration of DNA hybridization was investigated by different combinations of frequencies and amplitudes of actuating electric signals. Because the frequencies from low to high can induce different kinds of electrokinetic forces, i.e., electroosmotic to electrothermal forces, this work provides an in-depth investigation of electrokinetic enhanced hybridization. Concentric circular Cr/Au microelectrodes of 350 µm in diameter were fabricated on a glass substrate and probe DNA was immobilized on the electrode surface. Target DNA labeled with fluorescent dyes suspending in solution was then applied to the electrode. Different electrokinetic forces were induced by the application of different electric signals to the circular microelectrodes. Local microfluidic vortexes were generated to increase the collision efficiency between the target DNA suspending in solution and probe DNA immobilized on the electrode surface. DNA hybridization on the electrode surface could be accelerated by the electrokinetic forces. The level of hybridization was represented by the fluorescent signal intensity ratio. Results revealed that such 5-min dynamic hybridization increased 4.5 fold of signal intensity ratio as compared to a 1-h static hybridization. Moreover, dynamic hybridization was found to have better differentiation ability between specific and non-specific target DNA. This study provides a strategy to accelerate DNA hybridization in microsystems. PMID:25863384

  15. Induced-Charge Electrokinetic Phenomena: Theory and Microfluidic Applications

    Microsoft Academic Search

    Martin Z. Bazant; Todd M. Squires

    2004-01-01

    We give a general, physical description of ``induced-charge electro-osmosis''\\u000a(ICEO), the nonlinear electrokinetic slip at a polarizable surface, in the\\u000acontext of some new techniques for microfluidic pumping and mixing. ICEO\\u000ageneralizes ``AC electro-osmosis'' at micro-electrode arrays to various\\u000adielectric and conducting structures in weak DC or AC electric fields. The\\u000abasic effect produces micro-vortices to enhance mixing in microfluidic

  16. Effect of Incorporating Adaptive Functioning Scores on the Prevalence of Intellectual Disability

    ERIC Educational Resources Information Center

    Obi, Obianuju; Braun, Kim Van Naarden; Baio, Jon; Drews-Botsch, Carolyn; Devine, Owen; Yeargin-Allsopp, Marshalyn

    2011-01-01

    Surveillance and epidemiologic research on intellectual disability often do not incorporate adaptive functioning (AF) data. Exclusion of AF data leads to overestimation of the prevalence of intellectual disability, the extent of which is not known. In this study, the authors evaluated the effect of incorporating AF data on overall intellectual…

  17. Electrokinetic treatment of hazardous wastes in soil and groundwater

    SciTech Connect

    Loo, W.W. [Environment & Technology Services, San Francisco, CA (United States)

    1995-09-01

    Electrokinetic (EK) treatment processes are recognized by the US department of Defense, US Department of Energy, and the US EPA as the most potentially cost effective treatment of hazardous wastes. Recently, EK has attracted the attention of Dupont, General Electric, and Monsanto for various aspects of hazardous waste treatment. Electrolysis and electro-osmosis are known electrokinetic processes. Electrolysis is one of the principal industrial process used in the production of aluminum, chlorine, metal plating, welding, corrosion protection, etc. Electro-osmosis is a very well established process used to dewater and stabilize the clayey foundations of buildings and structures. These processes are very effective in the treatment of hazardous metals and organic compounds in soil, sludge, and water. Electrolysis can be applied in both permeable and impermeable media. It can be used as a neutralization process for pH control. It can also be used for the isolation or capture of metallic ions, or positively charged ions, at and near the cathode electrode. and negatively charged ions at and near the anode electrode. Electrolyis will also oxidize petroleum hydrocarbons and benzene-based organic chemicals such as PCBs, pesticides, and PAHs. Electro-osmosis can be used in the treatment of hazardous chemicals in silty and clayey material. The electro-osmotic process causes and imbalance of charge bonds in clayey material that results in clay compaction and chemical desorption. The compaction and desorption processes will reduce the cleanup time and are particularly successful in the desorption of organic chemicals and metals from clayey materials. This accelerates and improves the performance of typically inefficient pump and treat projects. Electrokinetic processes can be applied both above ground (ex situ) or in the subsurface (in situ).

  18. Enantioseparation of palonosetron hydrochloride by micellar electrokinetic chromatography with sodium cholate as chiral selector

    Microsoft Academic Search

    Kan Tian; Hongli Chen; Jianghong Tang; Xingguo Chen; Zhide Hu

    2006-01-01

    The enantioseparation of four stereoisomers of palonosetron hydrochloride by micellar electrokinetic chromatography using sodium cholate as chiral surfactant was described. Sodium cholate was shown to be effective in separating palonosetron hydrochloride stereoisomers. For method optimization, several parameters such as sodium cholate concentration, buffer pH and concentration, the types and concentration of organic modifiers and applied voltage, on the enantioseparation were

  19. [Effects of straw incorporation on rice carbon sequestration characteristics and grain yield formation].

    PubMed

    Pei, Peng-Gang; Zhang, Jun-Hua; Zhu, Lian-Feng; Yu, Sheng-Miao; Hu, Zhi-Hua

    2014-10-01

    A field experiment was conducted to study the effects of straw incorporation on rice dry matter accumulation and transportation, rice carbon sequestration and grain yield formation. The experiment included four levels of straw incorporation: 0 (control), 4000, 6000 and 8000 kg · hm(-2). Hybrid rice cultivar Zhongzheyou 1 was used in this experiment. The results showed that the average rice dry matter accumulation amount of the three straw incorporation treatments was increased by 63.03 g · m(-2) compared with the control, and that of straw incorporation of 6000 kg · hm(-2) showed the most favorable result, which was 154.40 g · m(-2) higher than the control. Effects of straw incorporation on rice dry matter accumulation showed the best performance from the maximum tillering stage to the full heading stage, and the dry matter accumulation at this stage was 71.25 g · m(-2) higher than the control. Compared with the control, the average dry matter exportation rate and apparent transformation rate from rice stem and leaf in the straw incorporation treatments were increased by 4.2% and 3.7%, respectively. The highest dry matter exportation rate and apparent transformation rate from rice stem and leaf were observed in the straw incorporation treatment of 6000 kg · hm(-2), which were increased by 12.8% and 11.1% compared to the control, respectively. The average rice carbon sequestration from the straw incorporation treatments was increased by 55.38 g · m(-2) compared with the control, and straw incorporation of 6000 kg · hm(-2) performed best with an increase of 17.8% compared with the control. Straw incorporation played a positive role in regulating the carbon sequestration of stem and leaf at the early growth stage and carbon sequestration of spike at the late growth stage. The average grain yield from the straw incorporation treatments was increased by 794.59 kg · hm(-2) (9.5% higher) compared with the control. Rice grain yields from the straw incorporation treatments of 6000 and 4000 kg · hm(-2) were significantly higher than the control, while rice grain yield from the straw incorporation treatment of 8000 kg · hm(-2) did not show a significant increase compared to the control. The rice grain yield was closely related to the yield components, and the increase of effective panicles may be the main reason for the higher grain yields in the straw incorporation treatments. Effective panicles in the straw incorporation treatments was averagely 8.41 spikes · m(-2) more than the control. PMID:25796896

  20. Spectral and Temporal Variability Incorporating General Relativistic Effects

    E-print Network

    Wiita, Paul J.

    and in the spectrum, as do motions of the power­law source. Here general relativistic effects are completely included the central engine (Guilbert & Rees 1988; Lightman & White 1988). If clouds (or disk regions) are dense enough of the spectrum arising directly from the accre­ tion disk, (e.g., Hollywood & Melia 1995). GR effects have

  1. Incorporating Conservation Zone Effectiveness for Protecting Biodiversity in Marine Planning

    PubMed Central

    Makino, Azusa; Klein, Carissa J.; Beger, Maria; Jupiter, Stacy D.; Possingham, Hugh P.

    2013-01-01

    Establishing different types of conservation zones is becoming commonplace. However, spatial prioritization methods that can accommodate multiple zones are poorly understood in theory and application. It is typically assumed that management regulations across zones have differential levels of effectiveness (“zone effectiveness”) for biodiversity protection, but the influence of zone effectiveness on achieving conservation targets has not yet been explored. Here, we consider the zone effectiveness of three zones: permanent closure, partial protection, and open, for planning for the protection of five different marine habitats in the Vatu-i-Ra Seascape, Fiji. We explore the impact of differential zone effectiveness on the location and costs of conservation priorities. We assume that permanent closure zones are fully effective at protecting all habitats, open zones do not contribute towards the conservation targets and partial protection zones lie between these two extremes. We use four different estimates for zone effectiveness and three different estimates for zone cost of the partial protection zone. To enhance the practical utility of the approach, we also explore how much of each traditional fishing ground can remain open for fishing while still achieving conservation targets. Our results show that all of the high priority areas for permanent closure zones would not be a high priority when the zone effectiveness of the partial protection zone is equal to that of permanent closure zones. When differential zone effectiveness and costs are considered, the resulting marine protected area network consequently increases in size, with more area allocated to permanent closure zones to meet conservation targets. By distributing the loss of fishing opportunity equitably among local communities, we find that 84–88% of each traditional fishing ground can be left open while still meeting conservation targets. Finally, we summarize the steps for developing marine zoning that accounts for zone effectiveness. PMID:24223870

  2. Fabrication and Characterization of Jute Fiber-Reinforced PET Composite: Effect of LLDPE Incorporation

    Microsoft Academic Search

    Tanzina Huq; Avik Khan; Nazia Noor; M. Saha; Ruhul A. Khan; Mubarak A. Khan; M. Mushfequr Rahman; K. Mustafizur Tahman

    2010-01-01

    The aim of the research was to study the effect of LLDPE incorporation in the jute fiber-reinforced PET composites (50% fiber by wt). The effect of LLDPE incorporation into PET was investigated by measuring the mechanical properties of the LLDPE blended jute fiber-reinforced PET composites. LLDPE was blended (20-80% by wt) with PET and the thin films were made by

  3. Electrostatic and electrokinetic contributions to the elastic moduli of a driven membrane

    NASA Astrophysics Data System (ADS)

    Lacoste, D.; Menon, G. I.; Bazant, M. Z.; Joanny, J. F.

    2009-03-01

    We discuss the electrostatic contribution to the elastic moduli of a cell or artificial membrane placed in an electrolyte and driven by a DC electric field. The field drives ion currents across the membrane, through specific channels, pumps or natural pores. In steady state, charges accumulate in the Debye layers close to the membrane, modifying the membrane elastic moduli. We first study a model of a membrane of zero thickness, later generalizing this treatment to allow for a finite thickness and finite dielectric constant. Our results clarify and extend the results presented by D. Lacoste, M. Cosentino Lagomarsino, and J.F. Joanny (EPL 77, 18006 (2007)), by providing a physical explanation for a destabilizing term proportional to k ? 3 in the fluctuation spectrum, which we relate to a nonlinear (E2) electrokinetic effect called induced-charge electro-osmosis (ICEO). Recent studies of ICEO have focused on electrodes and polarizable particles, where an applied bulk field is perturbed by capacitive charging of the double layer and drives the flow along the field axis toward surface protrusions; in contrast, we predict “reverse” ICEO flows around driven membranes, due to curvature-induced tangential fields within a nonequilibrium double layer, which hydrodynamically enhance protrusions. We also consider the effect of incorporating the dynamics of a spatially dependent concentration field for the ion channels.

  4. Electrostatic and electrokinetic contributions to the elastic moduli of a driven membrane.

    PubMed

    Lacoste, D; Menon, G I; Bazant, M Z; Joanny, J F

    2009-03-01

    We discuss the electrostatic contribution to the elastic moduli of a cell or artificial membrane placed in an electrolyte and driven by a DC electric field. The field drives ion currents across the membrane, through specific channels, pumps or natural pores. In steady state, charges accumulate in the Debye layers close to the membrane, modifying the membrane elastic moduli. We first study a model of a membrane of zero thickness, later generalizing this treatment to allow for a finite thickness and finite dielectric constant. Our results clarify and extend the results presented by D. Lacoste, M. Cosentino Lagomarsino, and J.F. Joanny (EPL 77, 18006 (2007)), by providing a physical explanation for a destabilizing term proportional to [see formula in text] in the fluctuation spectrum, which we relate to a nonlinear (E(2)) electrokinetic effect called induced-charge electro-osmosis (ICEO). Recent studies of ICEO have focused on electrodes and polarizable particles, where an applied bulk field is perturbed by capacitive charging of the double layer and drives the flow along the field axis toward surface protrusions; in contrast, we predict "reverse" ICEO flows around driven membranes, due to curvature-induced tangential fields within a nonequilibrium double layer, which hydrodynamically enhance protrusions. We also consider the effect of incorporating the dynamics of a spatially dependent concentration field for the ion channels. PMID:19184149

  5. Antitumor effect of cisplatin incorporated into polylactic acid microcapsules.

    PubMed

    Araki, H; Tani, T; Kodama, M

    1999-02-01

    Cisplatin containing microcapsules (CDDP-MC) were prepared by encapsulating cisplatin suspended in a dispersing agent in a copolymer (lactic acid) matrix using an in water drying method. Cisplatin release from the microcapsules was controlled by the addition of albumin. The CDDP-MC were relatively stable in storage, and there was only minimal initial release of the cisplatin from the microcapsules. The antitumor effects of this sustained release dosage form of cisplatin were evaluated in vitro and in vivo in mice. Mice were given an intraperitoneal (i.p.) injection of CDDP-MC 24 h after inoculation with tumor cells. The CDDP-MC were effective against Ehrlich ascites tumors and showed reduced acute toxicity compared with standard cisplatin solution. Due to the small initial release of the cisplatin from the microcapsules, however, the antitumor effect of the CDDP-MC was weaker than that of cisplatin solution. Conventional sustained release preparations have been reported to have large particle sizes and demonstrate large releases of cisplatin from microcapsules. They have been considered more effective than cisplatin solution because of the large initial release of cisplatin from the microcapsules and the maintenance of drug levels. The antitumor effect of our slow-release formulation of cisplatin was evaluated by administration of CDDP-MC 1, 4, and 7 days before i.p. implantation of tumor cells. The survival time of the tumor-bearing mice was prolonged in the CDDP-MC group, but not in the group treated with cisplatin solution. By using this modified formulation of cisplatin, the toxicity of the drug can be reduced, and effective concentrations of the drug can be maintained locally for prolonged periods of time. PMID:10027886

  6. Modeling the electrokinetic decontamination of concrete

    SciTech Connect

    Harris, M.T.; DePaoli, D.W.; Ally, M.R. [Oak Ridge National Lab., TN (United States)

    1997-01-01

    The decontamination of concrete is a major concern in many Department of (DOE) facilities. Numerous techniques (abrasive methods, manual methods, ultrasonics, concrete surface layer removal, chemical extraction methods, etc.) have been used to remove radioactive contamination from the surface of concrete. Recently, processes that are based on electrokinetic phenomena have been developed to decontaminate concrete. Electrokinetic decontamination has been shown to remove from 70 to over 90% of the surface radioactivity. To evaluate and improve the electrokinetic processes, a model has been developed to simulate the transport of ionic radionuclei constituents through the pores of concrete and into the anolyte and catholyte. The model takes into account the adsorption and desorption kinetics of the radionuclei from the pore walls, and ion transport by electro-osmosis, electromigration, and diffusion. A numerical technique, orthogonal collocation, is used to simultaneously solve the governing convective diffusion equations for a porous concrete slab and the current density equation. This paper presents the theoretical framework of the model and the results from the computation of the dynamics of ion transport during electrokinetic treatment of concrete. The simulation results are in good agreement with experimental data.

  7. CMOS inverter current and delay model incorporating interconnect effects

    Microsoft Academic Search

    M. Hafed; N. Rumin

    1998-01-01

    We present a new model for predicting the switching current and delay in a CMOS inverter with an RC load. The model exploits the ability of an inverter model to predict accurately the current peak time, tm, as a function of inverter size, input slope and capacitive load. An iterative procedure computes the effective capacitance presented by the RC load,

  8. Incorporating Neighborhood Effects in Customer Relationship Management Models

    Microsoft Academic Search

    Philippe Baecke; Dirk Van den Poel

    \\u000a Traditional customer relationship management (CRM) models often ignore the correlation that could exist in the purchase behavior\\u000a of neighboring customers. Instead of treating this correlation as nuisance in the error term, a generalized linear autologistic\\u000a regression can be used to take these neighborhood effects into account and improve the predictive performance of a customer\\u000a identification model for a Japanese automobile

  9. Pore network model of electrokinetic transport through charged porous media.

    PubMed

    Obliger, Amaël; Jardat, Marie; Coelho, Daniel; Bekri, Samir; Rotenberg, Benjamin

    2014-04-01

    We introduce a method for the numerical determination of the steady-state response of complex charged porous media to pressure, salt concentration, and electric potential gradients. The macroscopic fluxes of solvent, salt, and charge are computed within the framework of the Pore Network Model (PNM), which describes the pore structure of the samples as networks of pores connected to each other by channels. The PNM approach is used to capture the couplings between solvent and ionic flows which arise from the charge of the solid surfaces. For the microscopic transport coefficients on the channel scale, we take a simple analytical form obtained previously by solving the Poisson-Nernst-Planck and Stokes equations in a cylindrical channel. These transport coefficients are upscaled for a given network by imposing conservation laws for each pores, in the presence of macroscopic gradients across the sample. The complex pore structure of the material is captured by the distribution of channel diameters. We investigate the combined effects of this complex geometry, the surface charge, and the salt concentration on the macroscopic transport coefficients. The upscaled numerical model preserves the Onsager relations between the latter, as expected. The calculated macroscopic coefficients behave qualitatively as their microscopic counterparts, except for the permeability and the electro-osmotic coupling coefficient when the electrokinetic effects are strong. Quantitatively, the electrokinetic couplings increase the difference between the macroscopic coefficients and the corresponding ones for a single channel of average diameter. PMID:24827338

  10. Ultra-Strong Optomechanics Incorporating the Dynamical Casimir Effect

    E-print Network

    P. D. Nation; J. Suh; M. P. Blencowe

    2015-07-01

    We propose a superconducting circuit comprising a dc-SQUID with mechanically compliant arm embedded in a coplanar microwave cavity that realizes an optomechanical system with a degenerate or non-degenerate parametric interaction generated via the dynamical Casimir effect. For experimentally feasible parameters, this setup is capable of reaching the single-photon, ultra-strong coupling regime, while simultaneously possessing a parametric coupling strength approaching the renormalized cavity frequency. This opens up the possibility of observing the interplay between these two fundamental nonlinearities at the single-photon level.

  11. AC Electrokinetics of Physiological Fluids for Biomedical Applications.

    PubMed

    Lu, Yi; Liu, Tingting; Lamanda, Ariana C; Sin, Mandy L Y; Gau, Vincent; Liao, Joseph C; Wong, Pak Kin

    2014-12-01

    Alternating current (AC) electrokinetics is a collection of processes for manipulating bulk fluid mass and embedded objects with AC electric fields. The ability of AC electrokinetics to implement the major microfluidic operations, such as pumping, mixing, concentration, and separation, makes it possible to develop integrated systems for clinical diagnostics in nontraditional health care settings. The high conductivity of physiological fluids presents new challenges and opportunities for AC electrokinetics-based diagnostic systems. In this review, AC electrokinetic phenomena in conductive physiological fluids are described followed by a review of the basic microfluidic operations and the recent biomedical applications of AC electrokinetics. The future prospects of AC electrokinetics for clinical diagnostics are presented. PMID:25487557

  12. The Influence of Dielectric Decrement on Electrokinetics

    PubMed Central

    Zhao, Hui; Zhai, Shengjie

    2013-01-01

    We treat the dielectric decrement induced by excess ion polarization as a source of ion specificity and explore its impact on electrokinetics. We employ a modified Poisson-Nernst-Planck (PNP) equations accounting for the dielectric decrement. The dielectric decrement is determined by the excess ion polarization parameter ? and when ? = 0 the standard PNP model is recovered. Our model shows that ions saturate at large zeta potentials (?). Because of ion saturation, a condensed counterion layer forms adjacent to the charged surface, introducing a new length scale, the thickness of the condensed layer (lc). For the electro-osmotic mobility, the dielectric decrement weakens the electro-osmotic flow owing to the decrease of the dielectric permittivity. At large ?, when ? ? 0, the electro-osmotic mobility is found to be proportional to ?/2, in contrast to ? predicted by the standard PNP model. This is attributed to ion saturation at large ?. In terms of the electrophoretic mobility Me, we carry out both an asymptotic analysis in the thin-double-layer limit and solve the full modified PNP model to compute Me. Our analysis reveals that the impact of the dielectric decrement is intriguing. At small and moderate ?, the dielectric decrement decreases Me with an increasing ?. At large ?, it is well known that the surface conduction becomes significant and plays an important role in determining Me. It is observed that the dielectric decrement effectively reduces the surface conduction. Hence in stark contrast, Me increases as ? increases. Our predictions of the contrast dependence of the mobility on ? at different zeta potentials qualitatively agree with experimental results on the dependence of the mobility among ions and provide a possible explanation for such ion specificity. Finally, the comparisons between the thin-double-layer asymptotic analysis and the full simulations of the modified PNP model suggest that at large ? the validity of the thin-double-layer approximation is determined by lc rather than the traditional Debye length. PMID:24910471

  13. Electrokinetic remediation of mercury-contaminated soils using iodine/iodide lixiviant

    SciTech Connect

    Cox, C.D.; Shoesmith, M.A.; Ghosh, M.M. [Univ. of Tennessee, Knoxville, TN (United States)] [Univ. of Tennessee, Knoxville, TN (United States)

    1996-06-01

    In-situ remediation of mercury-contaminated soils, by electrokinetic or other means, is difficult because of the low solubility of mercury and its compounds. In this research, enhanced electrokinetic remediation of HgS-contaminated soils using I{sub 2}/I{sup -} lixiviant was investigated using bench-scale electrokinetic cells. The thermodynamic conditions under which the lixiviant could be effective were determined by constructing a pE-pH diagram for the Hg-S-I system. Introduced near the cathode, the lixiviant migrated through the soil to the anode by electromigration. Mercury, released by the oxidation of HgS compounds by I{sub 2}, was complexed as HgI{sub 4}{sup 2-}. The negative complex continued to electromigrate toward the anode. Up to 99% of the Hg present in laboratory-contaminated soils could be removed. Electrokinetic treatment of a field-contaminated soil, containing more organic matter than the laboratory-contaminated soil, occurred much slower. The critical issues in determining the efficacy of the process are the oxidation of reduced Hg by I{sub 2} and I{sub 3}{sup -} and the transport of the resultant HgI{sub 4}{sup 2-} complex. 17 refs., 7 figs., 2 tabs.

  14. Computing the Electrokinetic Response with Simple Models via Eigenvalue Decomposition

    NASA Astrophysics Data System (ADS)

    Kuhlman, K. L.; Malama, B.

    2010-12-01

    The efficient solution of coupled hydrogeophysical problems both numerically and analytically is important to their use in parameter estimation. We present a general approach for decoupling the governing equations for groundwater flow and the associated electrokinetic problem. The approach can use either a symbolic or numerical eigenvector decomposition of the matrix that arises when writing the two equations in vector form. The two coupled problems, once uncoupled, can then be solved using any existing approaches for the simple non-coupled component problems. Solutions can be either analytic or numerical in nature with the effective parameters being computed in the decomposition. The final solution, in terms of the physical potentials of interest, is computed through a simple matrix multiplication. We solve the fully coupled electrokinetic problem (water flow driving electrical flow and electrical flow driving water flow) for a single layer using the Theis solution, and for multilayer problems using MODFLOW. The approach is quite general, with the main limitation being a required symmetry between the coupled processes in their differential equation (e.g., both processes must be governed by the diffusion equation). The solution obtained with this approach is shown to agree with that obtained by Malama et al. (2009). Sandia National Laboratories is a multi-program laboratory operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000

  15. Laboratory scale electrokinetic remediation and geophysical monitoring of metal-contaminated marine sediments

    NASA Astrophysics Data System (ADS)

    Masi, Matteo; Pazzi, Veronica; Losito, Gabriella

    2013-04-01

    Electrokinetic remediation is an emerging technology that can be used to remove contaminants from soils and sediments. This technique relies on the application of a low-intensity electric field to extract heavy metals, radionuclides and some organic compounds. When the electric field is applied three main transport processes occur in the porous medium: electromigration, electroosmosis and electrophoresis. Monitoring of electrokinetic processes in laboratory and field is usually conducted by means of point measurements and by collecting samples from discrete locations. Geophysical methods can be very effective in obtaining high spatial and temporal resolution mapping for an adequate control of the electrokinetic processes. This study investigates the suitability of electrokinetic remediation for extracting heavy metals from dredged marine sediments and the possibility of using geophysical methods to monitor the remediation process. Among the geophysical methods, the spectral induced polarization technique was selected because of its capability to provide valuable information about the physico-chemical characteristics of the porous medium. Electrokinetic remediation experiments in laboratory scale were made under different operating conditions, obtained by varying the strength of the applied electric field and the type of conditioning agent used at the electrode compartments in each experiment. Tap water, 0.1M citric acid and 0.1M ethylenediamine tetraacetic acid (EDTA) solutions were used respectively as processing fluids. Metal removal was relevant when EDTA was used as conditioning agent and the electric potential was increased, as these two factors promoted the electroosmotic flow which is considered to be the key transport mechanism. The removal efficiencies ranged from 9.5% to 27% depending on the contaminant concerned. These percentages are likely to be raised by a further increase of the applied electric field. Furthermore, spectral induced polarization measurements were performed on the sediments before and after the treatment in order to correlate the measured electrical parameters with the geochemical processes occurring during electrokinetic remediation. A linear relationship was found between chargeability and pH. This result opens the door to the use of spectral induced polarization method to monitor electrokinetic processes in the field.

  16. Electrokinetic Stringency Control in Self-Assembled Monolayer-based Biosensors for Multiplex Urinary Tract Infection Diagnosis

    PubMed Central

    Liu, Tingting; Sin, Mandy L. Y.; Pyne, Jeff D.; Gau, Vincent; Liao, Joseph C.; Wong, Pak Kin

    2013-01-01

    Rapid detection of bacterial pathogens is critical toward judicious management of infectious diseases. Herein, we demonstrate an in situ electrokinetic stringency control approach for a self-assembled monolayer-based electrochemical biosensor toward urinary tract infection diagnosis. The in situ electrokinetic stringency control technique generates Joule heating induced temperature rise and electrothermal fluid motion directly on the sensor to improve its performance for detecting bacterial 16S rRNA, a phylogenetic biomarker. The dependence of the hybridization efficiency reveals that in situ electrokinetic stringency control is capable of discriminating single-base mismatches. With electrokinetic stringency control, the background noise due to the matrix effects of clinical urine samples can be reduced by 60%. The applicability of the system is demonstrated by multiplex detection of three uropathogenic clinical isolates with similar 16S rRNA sequences. The results demonstrate that electrokinetic stringency control can significantly improve the signal-to-noise ratio of the biosensor for multiplex urinary tract infection diagnosis. PMID:23891989

  17. Electrokinetic experimental study on saturated rock samples: zeta potential and surface conductance

    NASA Astrophysics Data System (ADS)

    Wang, Jun; Hu, Hengshan; Guan, Wei; Li, Hui

    2015-05-01

    It is important to know the electrokinetic properties of crustal rocks for interpreting the conductivity mechanisms and seismoelectric phenomena during earthquakes and seismoelectric well logging. In this study, electrokinetic experiments are conducted using a special core-holder by employing an AC lock-in technique. A series of experiments are conducted on 10 sandstone samples to measure the streaming potentials and streaming currents, and the experiments on each sample are done at six different salinities. The streaming potential coefficient and streaming current coefficient are calculated from the measured streaming potentials and streaming currents. The experimental results show that streaming potential coefficient and streaming current coefficient decrease as the salinity increases. The dependence of these two coefficients on permeability and pore radius are analysed and compared with previous works. At low salinities, the streaming potential coefficient and streaming current coefficient increase with the increasing permeability and pore radius. At high salinities, the streaming potential coefficient (streaming current coefficient) almost share a same value for 10 different samples. This conclusion indicates that the differences of rock parameters can only be well recognized at lower salinities, and the electrokinetic signals are invalid at high salinities, which offers a restrictive condition for using the amplitude of electrokinetic signals to estimate rock parameters. The zeta-potential have also been estimated through combined measurements of streaming potential and streaming current. The surface conductivity and its contribution to electrokinetic effects are determined from a comparison of zeta-potentials by two different methods, and then the validation of the Helmholz-Smoluchowski equation for a capillary tube is tested in rocks. We also compare our date with theoretical and experimental works, and set up an expression about the relationship between zeta potential and salinity, which fits the experimental data well.

  18. Probabilistic Seismic Hazard Estimates Incorporating Site Effects--An Example from Indiana, U.S.A.

    E-print Network

    Nowack, Robert L.

    Probabilistic Seismic Hazard Estimates Incorporating Site Effects--An Example from Indiana, U Stadium Mall Drive, West Lafayette, IN 47907-2051 JOHN R. HILL Indiana Geological Survey, 611 North Walnut and surrounding parts of central Indiana. This effect is primarily due to the relatively thick sequence

  19. Electrokinetic properties of the mammalian tectorial membrane

    PubMed Central

    Ghaffari, Roozbeh; Page, Scott L.; Farrahi, Shirin; Sellon, Jonathan B.; Freeman, Dennis M.

    2013-01-01

    The tectorial membrane (TM) clearly plays a mechanical role in stimulating cochlear sensory receptors, but the presence of fixed charge in TM constituents suggests that electromechanical properties also may be important. Here, we measure the fixed charge density of the TM and show that this density of fixed charge is sufficient to affect mechanical properties and to generate electrokinetic motions. In particular, alternating currents applied to the middle and marginal zones of isolated TM segments evoke motions at audio frequencies (1–1,000 Hz). Electrically evoked motions are nanometer scaled (?5–900 nm), decrease with increasing stimulus frequency, and scale linearly over a broad range of electric field amplitudes (0.05–20 kV/m). These findings show that the mammalian TM is highly charged and suggest the importance of a unique TM electrokinetic mechanism. PMID:23440188

  20. Liquid friction on charged surfaces: from hydrodynamic slippage to electrokinetics

    E-print Network

    Laurent Joly; Christophe Ybert; Emmanuel Trizac; Lyderic Bocquet

    2006-07-19

    Hydrodynamic behavior at the vicinity of a confining wall is closely related to the friction properties of the liquid/solid interface. Here we consider, using Molecular Dynamics simulations, the electric contribution to friction for charged surfaces, and the induced modification of the hydrodynamic boundary condition at the confining boundary. The consequences of liquid slippage for electrokinetic phenomena, through the coupling between hydrodynamics and electrostatics within the electric double layer, are explored. Strong amplification of electro-osmotic effects is revealed, and the non-trivial effect of surface charge is discussed. This work allows to reconsider existing experimental data, concerning Zeta potentials of hydrophobic surfaces and suggest the possibility to generate ``giant'' electro-osmotic and electrophoretic effects, with direct applications in microfluidics.

  1. A novel microfluidic driver via AC electrokinetics.

    PubMed

    Kuo, Ching-Te; Liu, Cheng-Hsien

    2008-05-01

    A novel ac electrokinetic microfluidic driver based on alternating current electro-osmosis flow induced by asymmetrically capacitance/chemistry-modulated microelectrode arrays has been successfully developed and demonstrated. Asymmetric capacitance modulation (ACM) is made of comb electrode arrays and parts of individual electrode surfaces are modulated/deposited with a SiO(2) dielectric layer. This proposed design can be utilized to shift the optimal operation frequency of maximum velocity to a higher frequency to minimize electrolytic bubble generation and enhance micropumping performance. The pumping velocity, described in this paper, is measured via the tracing of microbeads and is a function of applied potential, signal frequency, buffer concentration, and dielectric layer thickness. A maximum pumping velocity up to 290 microm s(-1) in 5 mM buffer solution with the applied potential of 10 Vpp is observed in our prototype device, and the estimated maximum flow rate is up to 26.1 microl h(-1). This is the first successful demonstration regarding bubble-free ac electrokinetic micropumping via such asymmetrically capacitance-modulated electrode arrays. Design, simulation, microfabrication, experimental result, and theoretical model are described in this paper to characterize and exhibit the performance of the proposed novel bubble-free ac electrokinetic microfluidic driver. PMID:18432342

  2. Cosolvent-enhanced electrokinetic remediation of soils contaminated with phenanthrene

    Microsoft Academic Search

    An Li; Kent A. Cheung; Krishna R. Reddy

    2000-01-01

    This research was carried out to evaluate feasibility of using an electrokinetic technique to remove hydrophobic organic pollutants from soils, with the assistance of a cosolvent (n-butylamine, tetrahydrofuran, or acetone) added to the conducting fluid. The experiments were carried out on glacial till clay with phenanthrene as the test compound. Desorption equilibrium was investigated by batch tests. The electrokinetic experiments

  3. The Utilization of Electrokinetics in Geotechnical and Environmental Engineering

    Microsoft Academic Search

    Rafig Azzam; Wolfgang Oey

    2001-01-01

    Electrokinetics can be utilized to solve many problems in geotechnical and environmental engineering. The processes which occur in association with electrokinetics are complicated and difficult to control. The success of the application depends on certain conditions which are controlled by many parameters. It is therefore important to understand these processes so that methods and procedures can be optimized. In this

  4. Modelling of Decontamination Rate in an Electrokinetic Soil Processing

    Microsoft Academic Search

    F. Baraud; M. C. Fourcade; S. Tellier; M. Astruc

    1997-01-01

    Modelling of the soil decontamination rate is developed for the case of an electrokinetic remediation run under controlled pH conditions. This model is based on a simple expression of the electrokinetic velocity of ionic species, including some parameters depending on the soil and pollutant species. Laboratory experiments run on kaolinite, using some cations as contaminant models fit well the theoretical

  5. A Laboratory-Scale Study of Applied Voltage on the Electrokinetic Separation of Lead from Soils

    Microsoft Academic Search

    Roger C. Viadero Jr; Brian E. Reed; Mitchell Berg; Joel Ramsey

    1998-01-01

    The application of electrokinetic (EK) soil-flushing technology to the separation of lead from a nonsynthetic, fine-grained, low permeability soil was examined. In these laboratory-scale experiments the effects of applied voltage (30 and 60 V DC) on cumulative electroosmotic (EO) flow, charge-input, and lead removal were investigated. To develop a more generalized cause-effect relationship, these parameters were studied using three anode\\/cathode

  6. Field Implementation of Electrokinetic-ISCO Remediation

    NASA Astrophysics Data System (ADS)

    Wu, M. Z.; Reynolds, D. A.; Fourie, A.; Thomas, D.; Prommer, H.

    2010-12-01

    Challenges remain in the remediation of low-permeability porous media (e.g. clays, silts) contaminated with dissolved and sorbed organic contaminants. Current remediation technologies, such as in-situ chemical oxidation (ISCO), are often ineffective and the treatment region is limited by very slow rates of groundwater flow (advection) or molecular diffusion. Several studies (e.g. Reynolds et al. 2008) have highlighted the potential at a laboratory scale for utilising electrokinetic transport, through the application of an electric field, to deliver a remediation compound (e.g. permanganate, persulfate) within heterogeneous and low-permeability sediments for ISCO (termed EK-ISCO) or other treatments. A numerical modelling approach is highly beneficial to optimise the efficacy of EK-ISCO remediation. A numerical model was developed that simulates groundwater flow and multi-species reactive transport under hydraulic and electric gradients (Wu et al. 2010). Coupled into the existing, previously verified reactive transport model PHT3D (Prommer, Barry and Zheng 2003), the model was verified against analytical and experimental studies. This study, through numerical modelling, investigated the feasibility of various factors, such as electrode configurations, applied voltage and oxidant loading, for EK-ISCO treatment at several field sites. Successful in situ oxidation is dependent upon the electrokinetic transport and dispersal of oxidant through the contaminated region, however this is limited by modelled conditions such as natural oxidant demand and contaminant phase. Electrode configurations investigated included one-dimensional or two-dimensional configurations, unidirectional, bidirectional or rotational operations, and position of oxidant injection. References Prommer, H, Barry, DA and Zheng, C 2003, 'MODFLOW/MT3DMS-Based Reactive Multicomponent Transport Modeling', Ground Water, vol. 41, no. 2, pp. 247-257. Reynolds, DA, Jones, EH, Gillen, M, Yusoff, I and Thomas, DG 2008, 'Electrokinetic migration of permanganate through low permeability porous media', Ground Water, vol. 46, no. 4, pp. 629-637. Wu, MZ, Reynolds, D, Prommer, H, Fourie, A, Thomas, D, Robertson, TJ and Hodges, D 2010, 'A Coupled Electrokinetic Transport and Geochemical Reaction Model', in Proceedings of The 9th Symposium on Electrokinetic Remediation (EREM 2010), ed. GCC Yang, National Sun-Yet Sen University, Kaohsiung, pp. 67-68.

  7. Incorporation and effect of arachidonic acid on the growth of human myeloma cell lines.

    PubMed Central

    Desplat, V; Dulery, C; Praloran, V; Denizot, Y

    1999-01-01

    The objectives of this work are to investigate the incorporation of arachidonic acid (AA) in the human myeloma cell lines OPM2, U266 and IM9, and to assess the effect of AA and lipoxygenase products of AA on their growth. The kinetics of acylation of [3H]AA indicates that myeloma cells incorporate AA into their membrane phospholipids and triglycerides. PLA2-treatment and base hydrolysis experiments confirm that [3H]AA is incorporated unmodified in U266, IM9 and OPM2 phospholipids, and is linked by an ester bond. Prelabeling-chase experiments indicate no trafficking of labeled AA among the various phospholipid species. Addition of AA and lipoxygenase products of AA (leukotriene B4 and C4, lipoxin A4 and B4, 12- and 15-hydroxyeicosatetraenoic acid) have no effect on U266, IM9 and OPM2 proliferation assessed by [3H]thymidine incorporation into DNA. In conclusion, while human myeloma cells readily incorporate AA in their membrane phospholipids and triglycerides, AA and lipoxygenase products are not important modulators of their proliferation. PMID:10704149

  8. The effect of incorporating cooperative learning principles in pair programming for student teachers

    Microsoft Academic Search

    E. Mentz; J. L. van der Walt; L. Goosen

    2008-01-01

    Based on their quantitative and qualitative investigations, the authors conclude that pair programming as a strategy for teaching student teachers could be made more effective through the incorporation of principles associated with cooperative learning. They substantiate this claim by referring to a literature study about the advantages and disadvantages of pair programming as a teaching-learning strategy, by then discussing five

  9. TWO STREAM MODEL FOR DOPANT DIFFUSION IN POLYSILICON INCORPORATING EFFECTS OF GRAIN

    E-print Network

    Dunham, Scott

    TWO STREAM MODEL FOR DOPANT DIFFUSION IN POLYSILICON INCORPORATING EFFECTS OF GRAIN GROWTH Soumya, Boston, MA 02215 Abstract We have developed a two stream model for dopant diffusion in polysilicon which kinetics and grain boundary segregation, as well as the interactions between these processes. TWO STREAM

  10. Low dose effect of ionizing radiation on incorporation of iododeoxyuridine into bone marrow cells.

    PubMed

    Zamboglou, N; Porschen, W; Mühlensiepen, H; Booz, J; Feinendegen, L E

    1981-01-01

    The reduction of the incorporation of IUdR in bone marrow cells depends on the time after irradiation and on te microenvironment of the cells. The strongest effect is observed 4 hours after irradiation. For absorbed doses above 40 rad, whole-body irradiated mice were more sensitive with respect to depression of IUdR incorporation in bone marrow cells, when the bone marrow cells were labelled in vivo, and less sensitive for in vitro labelling. The converse was observed for very small doses of 1 rad and below. Such small doses resulted in a significant depression of IUdR incorporation after in vivo irradiation and in vitro labelling and showed no effect at all after in vivo irradiation and in vivo labelling. The least effect of radiation was observed after both irradiation and labelling in vitro. Although the mechanisms are not fully understood, the biological results and microdosimetric considerations indicate that at the smallest doses the effect is due to functional changes of cellular organelles which control intracellular mechanisms. A working hypothesis is proposed for the reduction of IUdR incorporation at low doses as being due to functional changes of the cellular membranes. PMID:6971822

  11. Effect of direct incorporation of poultry litter on phosphorus leaching from coastal plain soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Management of poultry litter on the Delmarva Peninsula is critical to reducing phosphorus loads to the Chesapeake Bay. New poultry litter incorporation technologies have shown promise at reducing phosphorus losses, but their effectiveness has not been tested in this environmentally-sensitive region...

  12. Incorporating external evidence in trial-based cost-effectiveness analyses: the use of resampling methods

    PubMed Central

    2014-01-01

    Background Cost-effectiveness analyses (CEAs) that use patient-specific data from a randomized controlled trial (RCT) are popular, yet such CEAs are criticized because they neglect to incorporate evidence external to the trial. A popular method for quantifying uncertainty in a RCT-based CEA is the bootstrap. The objective of the present study was to further expand the bootstrap method of RCT-based CEA for the incorporation of external evidence. Methods We utilize the Bayesian interpretation of the bootstrap and derive the distribution for the cost and effectiveness outcomes after observing the current RCT data and the external evidence. We propose simple modifications of the bootstrap for sampling from such posterior distributions. Results In a proof-of-concept case study, we use data from a clinical trial and incorporate external evidence on the effect size of treatments to illustrate the method in action. Compared to the parametric models of evidence synthesis, the proposed approach requires fewer distributional assumptions, does not require explicit modeling of the relation between external evidence and outcomes of interest, and is generally easier to implement. A drawback of this approach is potential computational inefficiency compared to the parametric Bayesian methods. Conclusions The bootstrap method of RCT-based CEA can be extended to incorporate external evidence, while preserving its appealing features such as no requirement for parametric modeling of cost and effectiveness outcomes. PMID:24888356

  13. INCORPORATED SOURCE CARBON AND NITROGEN FERTILIZATION EFFECTS ON CARBON STORAGE AND SOLUBLE SILICA IN A HAPLOXEROLL

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Long-term field experiments with repeat additions of incorporated carbon sources are ideal to examine soil organic carbon (SOC) storage and its interaction with soil constituents. The objectives were to: i) determine the effect of crop residue management, N fertilizer, and organic amendments on SOC ...

  14. Incorporating psychosocial characteristics in cost-effectiveness modelling of Type 1 diabetes

    E-print Network

    Oakley, Jeremy

    Incorporating psychosocial characteristics in cost-effectiveness modelling of Type 1 diabetes Unit of Diabetes, Endocrinology and Metabolism, School of Medicine and Biomedical Sciences, University education programme that aims to teach individuals with Type 1 diabetes to change their self-care behaviours

  15. Alcohol Treatment and Cognitive-Behavioral Therapy: Enhancing Effectiveness by Incorporating Spirituality and Religion

    ERIC Educational Resources Information Center

    Hodge, David R.

    2011-01-01

    Cognitive-behavioral therapy (CBT) is an effective modality for the treatment of alcoholism. Given widespread interest in incorporating spirituality into professional treatment, this article orients practitioners to spiritually modified CBT, an approach that may enhance outcomes with some spiritually motivated clients. More specifically, by…

  16. Electrokinetic Hydrogen Generation from Liquid WaterMicrojets

    SciTech Connect

    Duffin, Andrew M.; Saykally, Richard J.

    2007-05-31

    We describe a method for generating molecular hydrogen directly from the charge separation effected via rapid flow of liquid water through a metal orifice, wherein the input energy is the hydrostatic pressure times the volume flow rate. Both electrokinetic currents and hydrogen production rates are shown to follow simple equations derived from the overlap of the fluid velocity gradient and the anisotropic charge distribution resulting from selective adsorption of hydroxide ions to the nozzle surface. Pressure-driven fluid flow shears away the charge balancing hydronium ions from the diffuse double layer and carries them out of the aperture. Downstream neutralization of the excess protons at a grounded target electrode produces gaseous hydrogen molecules. The hydrogen production efficiency is currently very low (ca. 10-6) for a single cylindrical jet, but can be improved with design changes.

  17. Desorption characteristics of kaolin clay contaminated with zinc from electrokinetic soil processing.

    PubMed

    Lee, Myung Ho; Kamon, Masashi; Kim, Soo Sam; Lee, Jai-Young; Chung, Ha Ik

    2007-08-01

    A number of bench scale laboratory column tests were carried out using a newly designed and developed electrokinetic cell to investigate the fundamental behavior of zinc-spiked kaolin clay subjected to an electric field. Laboratory investigations focused on (i) zinc migration by the combined effects of electromigration and electro-osmosis and (ii) the electrically induced desorption characteristics of zinc-contaminated kaolin that occurred during processing. The correlations of the applied voltage gradient, electro-osmotic flow rate, and the development of a pH gradient were examined and evaluated. The results showed that the removal efficiency was high during the early stage of processing due to rapid desorption by electrokinetic effects in the cathode region. However, the majority of zinc migrating from the anode was precipitated due to the high pH environment in the cathode region. PMID:17530420

  18. High Order WENO Simulation of Electrokinetic Instability in a Cross-Shaped Microchannel

    NASA Astrophysics Data System (ADS)

    Li, Qian; Delorme, Yann; Frankel, Steven

    2013-11-01

    Electroosmotic flow with electrokinetic effects is the primary method of fluid handling in micro-total analysis systems. Knowledge of electrokinetic instabilities (EKI) is required to trigger instabilities in applications like low Reynolds number micromixing or to suppress them in applications such as sample injection, separation and controlled diffusion-limited reaction processes where the minimum sample dispersion is needed. A novel multiblock high order in-house solver based on WENO scheme is applied to simulate the EKI for multiple electrolyte solutions with different electric conductivities in a cross-shaped microchannel. 3D simulations are performed to explore the effects of variations of applied electric field, electric field ratio, and conductivity ratios on the EKI phenomena, and to determine the critical value of electric field required for instabilities. The validity of the numerical study is assessed by comparing the numerical results with the experimental data.

  19. Role of the electrokinetic properties on the stability of mebendazole suspensions for veterinary applications.

    PubMed

    Cózar-Bernal, Ma José; Gallardo, Visitación; Sáez-Fernández, Eva; Holgado, Ma Angeles; Alvarez-Fuentes, Josefa; Fernández-Arévalo, Mercedes; Arias, José L

    2010-06-30

    This work is focused on the analysis of the effect of basic physicochemical aspects (surface thermodynamic and electrokinetic characteristics) on the stability and redispersibility properties of mebendazole aqueous suspensions. To our knowledge, previous investigations on the formulation of mebendazole suspensions have been not devoted to the elucidation of the colloidal behavior of this benzimidazole carbamate. A deep thermodynamic and electrokinetic characterization, considering the effect of both pH and ionic strength, was carried out with that purpose. It was found that the hydrophobicity and, the surface charge and electrical double layer thickness of the drug play a significant role in the stability of the colloid. Mebendazole aqueous suspensions display a controllable "delayed" or "hindered" sedimentation and a very easy redispersion which may contribute to the formulation of veterinary liquid dosage forms. PMID:20435113

  20. Electrokinetic microslit experiments to analyse the charge formation at solid\\/liquid interfaces

    Microsoft Academic Search

    Ralf Zimmermann; Toshihisa Osaki; Rüdiger Schweiß; Carsten Werner

    2006-01-01

    Electrokinetic effects play an important role in microfluidics and nanofluidics. Although the related phenomena are often utilized to control fluid flow and sample transport in lab-on-a-chip devices, their dependency on the surface charges on the channel walls often remain enigmatic. This is mainly due to the lack of adequate experimental methods to analyse the electrical charging of solid\\/liquid interfaces of

  1. Incorporating cost-effectiveness data in a fair process for priority setting efforts

    PubMed Central

    Youngkong, Sitaporn

    2015-01-01

    Cost-effectiveness data is useful for use in priority setting decisions in order to improve the efficiency of resources used. This paper thereby responds to Eckard et al. which addressed the use of cost-effectiveness data in the actual prioritization decisions in the Swedish national clinical guidelines for heart diseases. Based on a set of experiences on the use of economic evaluation in priority setting processes, this paper emphasizes the potential approach to incorporating cost-effectiveness data in the prioritization process to enhance transparency of the decisions, and highlights the importance of designing a fair decision-making process that can enforce the sustained implementation of cost-effectiveness data.

  2. Nonlinear electrokinetic phenomena Induced-charge electro-osmosis (ICEO), induced-charge electrophoresis (ICEP), AC electro-

    E-print Network

    Bazant, Martin Z.

    Nonlinear electrokinetic phenomena Synonyms Induced-charge electro-osmosis (ICEO), induced-charge electrophoresis (ICEP), AC electro- osmosis (ACEO), electro-osmosis of the second kind, electrophoresis a capacitor skin on the surface. Electro-osmosis produces an effective slip of the liquid outside the double

  3. Analysis of insecticidal proteins from Bacillus thuringiensis and recombinant Escherichia coli by capillary electrokinetic chromatography.

    PubMed

    Luong, John H T; Male, Keith B; Mazza, Alberto; Masson, Luke; Brousseau, Roland

    2004-10-01

    Bacillus thuringiensis and recombinant Escherichia coli proteinaceous protoxins were subject to proteolysis and analyzed by capillary electrokinetic chromatography. Three resulting toxins (65 kDa) were baseline-resolved within 22 min using a 10 mM borate, pH 11 separation buffer consisting of 25 mM sodium dodecyl sulfate (SDS) and 30 mM phytic acid. The toxins displayed differential interactions with the SDS and phytic acid phases to effect their separation. The ion-pairing interaction between the analyte and phytic acid was also useful in preventing adsorption to the capillary walls and thus enhanced separation resolution and efficiency. The use of electrokinetic chromatography allows achievement of the separation in a significantly shorter time than conventional high-performance liquid chromatography (HPLC) using a diethylaminoethyl (DEAE) weak-anion exchanger. PMID:15472953

  4. Polymeric and polymer-supported pseudostationary phases in micellar electrokinetic chromatography: performance and selectivity.

    PubMed

    Palmer, C P

    2000-12-01

    Several types of synthetic ionic polymers have been employed as pseudostationary phases in electrokinetic chromatography. The polymers have been shown to have some significant advantages and different chemical selectivity relative to conventional surfactant micelles. Polymeric phases are effective for the separation and analysis of hydrophobic and chiral compounds, and may be useful for the application of mass spectrometric detection. Additionally, the polymeric phases often demonstrate unique selectivity relative to micellar phases, and can be designed and synthesized to provide desired selectivity. This review covers efforts to develop and characterize the performance, characteristics, and selectivity of synthetic polymeric pseudostationary phases since their introduction in 1992. Some ideas for the future development of polymeric pseudostationary phases and the role they may play in electrokinetic separations are presented. PMID:11192124

  5. Label-free attomolar detection of proteins using integrated nanoelectronic and electrokinetic devices.

    PubMed

    Gong, Jian-Ru

    2010-04-23

    High-sensitivity screening of biomarkers is critical to areas ranging from early disease detection and diagnosis to bioterrorism surveillance. Here the development of integrated nanoelectronic and electrokinetic devices for label-free attomolar detection of proteins is reported. Electrically addressable silicon nanowire field-effect transistors and electrodes for electrokinetic transport are integrated onto a common sensor chip platform, and the nanowire devices are subsequently functionalized with receptors for selective biomarker detection. Nanowire devices modified with monoclonal antibody for prostate specific antigen exhibit close to a 10(4) increase in sensitivity due to streaming dielectrophoresis and corresponding electrostatic contribution to the binding affinity after application of an AC electric field. The devices are also modified with receptors for cholera toxin subunit B and achieve a similar enhancement. These results show general applicability of this method, and could open up opportunities in early stage disease detection and the analysis of proteins from single cells. PMID:20209654

  6. In Situ Electrokinetic Enhancement for Self-Assembled-Monolayer-Based Electrochemical Biosensing

    PubMed Central

    Sin, Mandy L. Y.; Liu, Tingting; Pyne, Jeffrey D.; Gau, Vincent; Liao, Joseph C.; Kin Wong, Pak

    2014-01-01

    This study reports a multifunctional electrode approach which directly implements electrokinetic enhancement on a self-assembled-monolayer-based electro-chemical sensor for point-of-care diagnostics. Using urinary tract infections as a model system, we demonstrate that electrokinetic enhancement, which involves in situ stirring and heating, can enhance the sensitivity of the strain specific 16S rRNA hybridization assay for 1 order of magnitude and accelerate the time-limiting incubation step with a 6-fold reduction in the incubation time. Since the same electrode platform is used for both electrochemical signal enhancement and electrochemical sensing, the multifunctional electrode approach provides a highly effective strategy toward fully integrated lab-on-a-chip systems for various biomedical applications. PMID:22397486

  7. Ultraviolet irradiation effects incorporation of nitrate and nitrite nitrogen into aquatic natural organic matter

    USGS Publications Warehouse

    Thorn, Kevin A.; Cox, Larry G.

    2012-01-01

    One of the concerns regarding the safety and efficacy of ultraviolet radiation for treatment of drinking water and wastewater is the fate of nitrate, particularly its photolysis to nitrite. In this study, 15N NMR was used to establish for the first time that UV irradiation effects the incorporation of nitrate and nitrite nitrogen into aquatic natural organic matter (NOM). Irradiation of 15N-labeled nitrate in aqueous solution with an unfiltered medium pressure mercury lamp resulted in the incorporation of nitrogen into Suwannee River NOM (SRNOM) via nitrosation and other reactions over a range of pH from approximately 3.2 to 8.0, both in the presence and absence of bicarbonate, confirming photonitrosation of the NOM. The major forms of the incorporated label include nitrosophenol, oxime/nitro, pyridine, nitrile, and amide nitrogens. Natural organic matter also catalyzed the reduction of nitrate to ammonia on irradiation. The nitrosophenol and oxime/nitro nitrogens were found to be susceptible to photodegradation on further irradiation when nitrate was removed from the system. At pH 7.5, unfiltered irradiation resulted in the incorporation of 15N-labeled nitrite into SRNOM in the form of amide, nitrile, and pyridine nitrogen. In the presence of bicarbonate at pH 7.4, Pyrex filtered (cutoff below 290–300 nm) irradiation also effected incorporation of nitrite into SRNOM as amide nitrogen. We speculate that nitrosation of NOM from the UV irradiation of nitrate also leads to production of nitrogen gas and nitrous oxide, a process that may be termed photo-chemodenitrification. Irradiation of SRNOM alone resulted in transformation or loss of naturally abundant heterocyclic nitrogens.

  8. Effect of incorporation of carbon nanotubes on the mechanical properties of epoxy-amine composites

    NASA Astrophysics Data System (ADS)

    Raimondo, Marialuigia; Guadagno, Liberata

    2012-07-01

    In this work, the effect of incorporation of multi-wall carbon nanotubes (MWCNTs) on the dynamic mechanical properties of epoxy-amine composites for structural applications was investigated. The composites were prepared by dispersing MWCNTs into an epoxy resin based on TetraGlycidyl-MethyleneDiAniline (TGMDA) and both epoxy precursor and composite were cured with 4,4'-diamino diphenyl sulfone (DDS). Morphological investigation by atomic force microscopy (AFM) indicates efficient dispersion of MWCNTs in the thermosetting matrix. The dynamic mechanical properties show very high values in the storage modulus and glass transition temperature. The incorporation of MWCNTs induces an increase in the storage modulus and a change in the curve profile of tg ? suggesting a small fraction with lower mobility due to a different degree of crosslinking. A more effective curing cycle allows to compensate this drawback due to the inclusion of nanofiller inside epoxy matrix.

  9. Synthesis of monomethoxypolyethyleneglycol-cholesteryl ester and effect of its incorporation in liposomes.

    PubMed

    Sant, Vinayak P; Nagarsenker, Mangal S

    2011-12-01

    The objective of the present study was to synthesize monomethoxypolyethyleneglycol-5000 cholesteryl ester [PEG-CH] as a cost-effective substitute for polyethyleneglycol-phosphatidylethanolamine and to evaluate the influence of its incorporation in liposomal bilayers for surface modification. PEG-CH was synthesized and characterized by infrared (IR), proton nuclear magnetic resonance spectroscopy ((1)H NMR), and differential scanning calorimetry (DSC) studies. Influence of incorporation of PEG-CH in liposomes was evaluated on various parameters such as zeta potential, DSC, and encapsulation efficiency of a hydrophilic drug pentoxyfylline. Conventional and PEG-CH containing pentoxyfylline liposomes were formulated and their stability was evaluated at 4°C for 3 months. PEG-CH could be successfully synthesized with good yields and the structure was confirmed by IR, DSC, and (1)H NMR. The incorporation of PEG-CH in liposomes resulted in reduction of the zeta potential and broadening of the DSC endotherm. Furthermore, incorporation of PEG-CH in liposomes decreased the encapsulation efficiency of pentoxifylline in liposomes when compared to conventional liposomes. Conventional and PEG-CH containing pentoxyfylline liposomes did not show any signs of pentoxyfylline degradation when stored at 4°C for 3 months. PMID:21853369

  10. Effect of silver nanoparticles incorporation on viscoelastic properties of acrylic resin denture base material

    PubMed Central

    Mahross, Hamada Zaki; Baroudi, Kusai

    2015-01-01

    Objective: The objective was to investigate the effect of silver nanoparticles (AgNPs) incorporation on viscoelastic properties of acrylic resin denture base material. Materials and Methods: A total of 20 specimens (60 × 10 × 2 mm) of heat cured acrylic resin were constructed and divided into four groups (five for each), according to the concentration of AgNPs (1%, 2%, and 5% vol.) which incorporated into the liquid of acrylic resin material and one group without additives (control group). The dynamic viscoelastic test for the test specimens was performed using the computerized material testing system. The resulting deflection curves were analyzed by material testing software NEXYGEN MT. Results: The 5% nanoparticles of silver (NAg) had significantly highest mean storage modulus E’ and loss tangent Tan ? values followed by 2% NAg (P < 0.05). For 1% nanosilver incorporation (group B), there were no statistically significant differences in storage modulus E’, lost modulus E” or loss tangent Tan ? with other groups (P > 0.05). Conclusion: The AgNPs incorporation within the acrylic denture base material can improve its viscoelastic properties.

  11. Towards an understanding of induced-charge electrokinetics at large applied voltages in concentrated solutions.

    PubMed

    Bazant, Martin Z; Kilic, Mustafa Sabri; Storey, Brian D; Ajdari, Armand

    2009-11-30

    The venerable theory of electrokinetic phenomena rests on the hypothesis of a dilute solution of point-like ions in quasi-equilibrium with a weakly charged surface, whose potential relative to the bulk is of order the thermal voltage (kT/e approximately 25 mV at room temperature). In nonlinear electrokinetic phenomena, such as AC or induced-charge electro-osmosis (ACEO, ICEO) and induced-charge electrophoresis (ICEP), several V approximately 100 kT/e are applied to polarizable surfaces in microscopic geometries, and the resulting electric fields and induced surface charges are large enough to violate the assumptions of the classical theory. In this article, we review the experimental and theoretical literatures, highlight discrepancies between theory and experiment, introduce possible modifications of the theory, and analyze their consequences. We argue that, in response to a large applied voltage, the "compact layer" and "shear plane" effectively advance into the liquid, due to the crowding of counterions. Using simple continuum models, we predict two general trends at large voltages: (i) ionic crowding against a blocking surface expands the diffuse double layer and thus decreases its differential capacitance, and (ii) a charge-induced viscosity increase near the surface reduces the electro-osmotic mobility; each trend is enhanced by dielectric saturation. The first effect is able to predict high-frequency flow reversal in ACEO pumps, while the second may explain the decay of ICEO flow with increasing salt concentration. Through several colloidal examples, such as ICEP of an uncharged metal sphere in an asymmetric electrolyte, we show that nonlinear electrokinetic phenomena are generally ion-specific. Similar theoretical issues arise in nanofluidics (due to confinement) and ionic liquids (due to the lack of solvent), so the paper concludes with a general framework of modified electrokinetic equations for finite-sized ions. PMID:19879552

  12. Incorporating many-body effects into modeling of semiconductor lasers and amplifiers

    SciTech Connect

    Ning, C.Z.; Moloney, J.V.; Indik, R.A. [Univ. of Arizona, Tucson, AZ (United States)] [and others

    1997-06-01

    Major many-body effects that are important for semiconductor laser modeling are summarized. The authors adopt a bottom-up approach to incorporate these many-body effects into a model for semiconductor lasers and amplifiers. The optical susceptibility function ({Chi}) computed from the semiconductor Bloch equations (SBEs) is approximated by a single Lorentzian, or a superposition of a few Lorentzians in the frequency domain. Their approach leads to a set of effective Bloch equations (EBEs). The authors compare this approach with the full microscopic SBEs for the case of pulse propagation. Good agreement between the two is obtained for pulse widths longer than tens of picoseconds.

  13. Bone marrow ribonucleic acid polymerase. Effect of testosterone on nucleotide incorporation into nuclear RNA.

    PubMed Central

    Valladares, L E; Cañas, P E; Minguell, J J

    1976-01-01

    The incorporation of 3H-UTP into RNA by isolated rat bone marrow nuclei is stimulated by testosterone. This effect is hormone and tissue specific. Using alpha-amanitine and different ionic strength conditions it was found that testosterone enhances preferentially RNA polymerase I activity. The sedimentation pattern of RNA isolated from bone marrow nuclei shows that the synthesis of RNA species within the 14-30 S range is mainly stimulated by the hormone. PMID:1005113

  14. EFFECTS OF PT INCORPORATION ON THE ISOTHERMAL OXIDATION BEHAVIOR OF CVD ALUMINIDE COATINGS

    Microsoft Academic Search

    Y. Zhang; J. A. Haynes; W. Y. Lee; I. G. Wright; B. A. Pint; K. M. Cooley

    The effects of Pt incorporation on the isothermal oxidation and diffusion behavior of low-sulfur aluminide bond coatings were investigated. Aluminide (NiAl) coatings and Pt- modified aluminide (Ni,Pt)Al coatings were synthesized on a low-sulfur, yttrium-free single- crystal Ni-based superalloy by a high-purity, low-activity chemical vapor deposition (CVD) aluminizing procedure. The isothermal oxidation kinetics and scale adhesion behavior of CVD NiAl and

  15. Overcoming chromatic-dispersion effects in fiber-wireless systems incorporating external modulators

    Microsoft Academic Search

    Graham H. Smith; Dalma Novak; Zaheer Ahmed

    1997-01-01

    We demonstrate two techniques to reduce the effects of fiber chromatic dispersion in fiber-wireless systems incorporating external modulators. We theoretically and experimentally show that the achievable link distance can be increased by varying the chirp parameter of the modulator to give large negative chirp using a dual-electrode Mach-Zehnder modulator (MZM) biased at quadrature. In addition, we show that dispersion can

  16. Electrokinetic trapping at the one nanometer limit

    PubMed Central

    Fields, Alexander P.; Cohen, Adam E.

    2011-01-01

    Anti-Brownian electrokinetic traps have been used to trap and study the free-solution dynamics of large protein complexes and long chains of DNA. Small molecules in solution have thus far proved too mobile to trap by any means. Here we explore the ultimate limits on trapping single molecules. We developed a feedback-based anti-Brownian electrokinetic trap in which classical thermal noise is compensated to the maximal extent allowed by quantum measurement noise. We trapped single fluorophores with a molecular weight of < 1 kDa and a hydrodynamic radius of 6.7 ? for longer than one second, in aqueous buffer at room temperature. This achievement represents an 800-fold decrease in the mass of objects trapped in solution, and opens the possibility to trap and manipulate any soluble molecule that can be fluorescently labeled. To illustrate the use of this trap, we studied the binding of unlabeled RecA to fluorescently labeled single-stranded DNA. Binding of RecA induced changes in the DNA diffusion coefficient, electrophoretic mobility, and brightness, all of which were measured simultaneously and on a molecule-by-molecule basis. This device greatly extends the size range of molecules that can be studied by room temperature feedback trapping, and opens the door to further studies of the binding of unmodified proteins to DNA in free solution. PMID:21562206

  17. Treatment of sewage sludge using electrokinetic geosynthetics.

    PubMed

    Glendinning, Stephanie; Lamont-Black, John; Jones, Colin J F P

    2007-01-31

    The treatment and disposal of sewage sludge is one of the most problematical issues affecting wastewater treatment in the developed world. The traditional outlets for sewage sludge are to spread it on agricultural land, or to form a cake for deposit to landfill or incineration. In order to create a sludge cake, water must be removed. Existing dewatering technology based on pressure can only remove a very limited amount of this water because of the way in which water is bound to the sludge particles or flocs. Several researchers have shown that electrokinetic dewatering of sludge is more efficient than conventional hydraulically driven methods. This involves the application of a dc voltage across the sludge, driving water under an electrical gradient from positive (anode) electrode to negative (cathode) electrode. However, there have been several reasons why this technique has not been adopted in practice, not least because the, normally metallic, anode rapidly dissolves due to the acidic environment created by the electrolysis of water. This paper will describe experimentation using electrokinetic geosynthetics (EKG): polymer-based materials containing conducting elements. These have been used to minimise the problem of electrode corrosion and create a sludge treatment system that can produce dry solids contents in excess of 30%. It will suggest different options for the treatment of sludges both in situ in sludge lagoons and windrows, and ex situ as a treatment process. PMID:16635546

  18. The effect of osteoimmunomodulation on the osteogenic effects of cobalt incorporated ?-tricalcium phosphate.

    PubMed

    Chen, Zetao; Yuen, Jones; Crawford, Ross; Chang, Jiang; Wu, Chengtie; Xiao, Yin

    2015-08-01

    Osteoblast lineage cells are direct effectors of osteogenesis and are, therefore, commonly used to evaluate the in vitro osteogenic capacity of bone substitute materials. This method has served its purposes when testing novel bone biomaterials; however, inconsistent results between in vitro and in vivo studies suggest the mechanisms that govern a material's capacity to mediate osteogenesis are not well understood. The emerging field of osteoimmunology and immunomodulation has informed a paradigm shift in our view of bone biomaterials-from one of an inert to an osteoimmunomodulatory material-highlighting the importance of immune cells in materials-mediated osteogenesis. Neglecting the importance of the immune response during this process is a major shortcoming of the current evaluation protocol. In this study we evaluated a potential angiogenic bone substitute material cobalt incorporated with ?-tricalcium phosphate (CCP), comparing the traditional "one cell type" approach with a "multiple cell types" approach to assess osteogenesis, the latter including the use of immune cells. We found that CCP extract by itself was sufficient to enhance osteogenic differentiation of bone marrow stem cells (BMSCs), whereas this effect was cancelled out when macrophages were involved. In response to CCP, the macrophage phenotype switched to the M1 extreme, releasing pro-inflammatory cytokines and bone catabolic factors. When the CCP materials were implanted into a rat femur condyle defect model, there was a significant increase of inflammatory markers and bone destruction, coupled with fibrous encapsulation rather than new bone formation. These findings demonstrated that the inclusion of immune cells (macrophages) in the in vitro assessment matched the in vivo tissue response, and that this method provides a more accurate indication of the essential role of immune cells when assessing materials-stimulated osteogenesis in vitro. PMID:26001077

  19. Application of sequential extraction analysis to electrokinetic remediation of cadmium, nickel and zinc from contaminated soils.

    PubMed

    Giannis, Apostolos; Pentari, Despina; Wang, Jing-Yuan; Gidarakos, Evangelos

    2010-12-15

    An enhanced electrokinetic process for the removal of cadmium (Cd), nickel (Ni) and zinc (Zn) from contaminated soils was performed. The efficiency of the chelate agents nitrilotriacetic acid (NTA), diethylenetriaminepentaacetic acid (DTPA) and diaminocycloexanetetraacetic acid (DCyTA) was examined under constant potential gradient (1.23 V/cm). The results showed that chelates were effective in desorbing metals at a high pH, with metal-chelate anion complexes migrating towards the anode. At low pH, metals existing as dissolved cations migrated towards the cathode. In such conflicting directions, the metals accumulated in the middle of the cell. Speciation of the metals during the electrokinetic experiments was performed to provide an understanding of the distribution of the Cd, Ni and Zn. The results of sequential extraction analysis revealed that the forms of the metals could be altered from one fraction to another due to the variation of physico-chemical conditions throughout the cell, such as pH, redox potential and the chemistry of the electrolyte solution during the electrokinetic treatment. It was found that binding forms of metals were changed from the difficult type to easier extraction type. PMID:20833468

  20. Effect of cobalt incorporation and lithium enrichment in lithium nickel manganese oxides.

    SciTech Connect

    Deng, H.; Belharouak, I.; Wu, H.; Dambournet, D.; Amine, K. (Chemical Sciences and Engineering Division)

    2010-05-10

    Candidate cathode materials of cobalt-incorporated and lithium-enriched Li{sub (1+x)}Ni{sub 0.25}Co{sub 0.15}Mn{sub 0.6}O{sub (2.175+x/2)} (x=0.225-0.65) have been prepared by a coprecipitation method and a solid-state reaction. We systematically investigated the effect of both cobalt presence and lithium concentration on the structure, physical properties, and electrochemical behavior of the studied samples. The electrochemical performance of the cobalt-containing compounds showed much less dependence on the variation in the lithium amounts compared to the cobalt-free counterpart. The study demonstrated that even with cobalt incorporation, proper lithium content is the key to desirable cathode materials with nanostructured primary particles that are indispensable to achieve high capacity and high rate capability and, therefore, both improved energy and power densities for lithium-ion batteries.

  1. Induced Charge Electrokinetic Phenomena in Tapered Conducting Nanochannels

    E-print Network

    Zhao, Cunlu

    2010-01-01

    We conducted a fundamental study of electrokinetics in conducting (ideally polarizable) tapered nanochannels. Based on the theory of induced charge electrokinetics, the external driving electric fields polarize the uncharged conducting walls of nanochannels and consequently induce surface charges on these walls which also can play the roles of physiochemical bond charges in conventional electrokinetics. Due to complex coupling involved in the problem, the complete model including the Poisson equation for electric potential, the Nernst-Planck equation for ions transport and the Navier-stokes equation for liquid transport are adopted to numerically investigate the electrokinetic phenomena inside the tapered nanofluidic nanochannel with conducting walls. The results reveal that, the flow inside the tapered conducting nanochannel exhibit so-called full wave flow rectification that the electrolyte solution always flows from the narrow end of a nanochannel to the wide end for either a forward bias (electric field f...

  2. DEMONSTRATION BULLETIN: IN SITU ELECTROKINETIC EXTRACTION SYSTEM - SANDIA NATIONAL LABORATORIES

    EPA Science Inventory

    Sandia National Laboratories (SNL) has developed an in situ soil remediation system that uses electrokinetic principles to remediate hexavalent chromium-contaminated unsaturated or partially saturated soils. The technology involves the in situ application of direct current to the...

  3. Effect of silver incorporation in phase formation and band gap tuning of tungsten oxide thin films

    SciTech Connect

    Jolly Bose, R.; Kumar, R. Vinod; Sudheer, S. K.; Mahadevan Pillai, V. P. [Department of Optoelectronics, University of Kerala, Kariyavattom, Thiruvananthapuram, Kerala 695581 (India); Reddy, V. R.; Ganesan, V. [UGC - DAE Consortium for Scientific Research, Khandwa Road, Indore 452017, Madhyapradesh (India)

    2012-12-01

    Silver incorporated tungsten oxide thin films are prepared by RF magnetron sputtering technique. The effect of silver incorporation in micro structure evolution, phase enhancement, band gap tuning and other optical properties are investigated using techniques such as x-ray diffraction, micro-Raman spectroscopy, atomic force microscopy, scanning electron microscopy, energy dispersive x-ray spectroscopy, and UV-Visible spectroscopy. Effect of silver addition in phase formation and band gap tuning of tungsten oxide thin films are investigated. It is found that the texturing and phase formation improves with enhancement in silver content. It is also found that as the silver incorporation enhances the thickness of the films increases at the same time the strain in the film decreases. Even without annealing the desired phase can be achieved by doping with silver. A broad band centered at the wavelength 437 nm is observed in the absorption spectra of tungsten oxide films of higher silver incorporation and this can be attributed to surface plasmon resonance of silver atoms present in the tungsten oxide matrix. The transmittance of the films is decreased with increase in silver content which can be due to increase in film thickness, enhancement of scattering, and absorption of light caused by the increase of grain size, surface roughness and porosity of films and enhanced absorption due to surface plasmon resonance of silver. It is found that silver can act as the seed for the growth of tungsten oxide grains and found that the grain size increases with silver content which in turn decreases the band gap of tungsten oxide from 3.14 eV to 2.70 eV.

  4. A microfluidic chip for heterogeneous immunoassay using electrokinetical control

    Microsoft Academic Search

    Guoqing Hu; Yali Gao; Philip M. Sherman; Dongqing Li

    2005-01-01

    This article presents the development of a novel, automated, electrokinetically controlled heterogeneous immunoassay on a poly(dimethylsiloxane) (PDMS) microfluidic chip. A numerical method has been developed to simulate the electrokinetically driven, time-dependent delivery processes of reagents and washing solutions within the complex microchannel network. Based on the parameters determined from the numerical simulations, fully automated on-chip experiments to detect Helicobacter pylori

  5. Improvement of reproducibility and sensitivity by reducing matrix effect in micellar electrokinetic chromatography for determination of amino acids in turtle jelly.

    PubMed

    Li, Lin-Qiu; Cai, Yue; Yang, Mei; Shen, Qing; Yu, Ka-Ming; Cheung, Hon-Yeung

    2015-05-01

    Matrix effect (ME) is commonly seen in electrophoretic separation, but this phenomenon lacks any systematic study. Our work aimed to find out the relationship between separation efficiency and current, and then figure out an effective, simple, and economic solution to overcome the negative impact of ME. This present study showed that small amount of NaCl (?0.005 mg/mL) in the sample had no impact on the separation but enhanced the sensitivity. However, when concentration of NaCl increased above 0.005 mg/mL, it alleviated the separation efficiency, sensitivity, and migration time. Besides, increasing NaCl concentration resulted in increasing turning point. The study of relationship of current and NaCl concentration indicated that when the TP of a sample is higher than 62.36 ?A, desalination is necessary. Since the reported desalination methods are either expensive or complicated, we developed a simple and economic method by simply adding 12 times (volume) of chloroform/methanol (2:1, v/v) into the sample. When applied this method to turtle jelly, the number of theoretical plate (N) of 20 amino acids got up to threefold enhancement. PMID:25781419

  6. Interindividual variability and ontogenetic effects on Mg and Sr incorporation in the planktonic foraminifer Globigerinoides sacculifer

    NASA Astrophysics Data System (ADS)

    Dueñas-Bohórquez, Adriana; da Rocha, Régine Elisabeth; Kuroyanagi, Azumi; de Nooijer, Lennart J.; Bijma, Jelle; Reichart, Gert-Jan

    2011-01-01

    In order to investigate the interindividual and ontogenetic effects on Mg and Sr incorporation, magnesium/calcium (Mg/Ca) and strontium/calcium (Sr/Ca) ratios of cultured planktonic foraminifera have been determined. Specimens of Globigerinoides sacculifer were grown under controlled physical and chemical seawater conditions in the laboratory. By using this approach, we minimised the effect of potential environmental variability on Mg/Ca and Sr/Ca ratios. Whereas temperature is the overriding control of Mg/Ca ratios, the interindividual variability observed in the Mg/Ca values contributes 2-3 °C to the apparent temperature variance. Interindividual variability in Sr/Ca ratios is much smaller than that observed in Mg/Ca values. The variability due to ontogeny corresponds to -0.43 mmol/mol of Mg/Ca ratio per chamber added. This translates into an apparent decrease of ˜1 °C in Mg/Ca-based temperature per ontogenetic (chamber) stage. No significant ontogenetic effect is observed on Sr incorporation. We conclude that the presence of a significant ontogenetic effect on Mg incorporation can potentially offset Mg/Ca-based temperature reconstructions. We propose two new empirical Mg/Ca-temperature equation based on Mg/Ca measurements of the last four ontogenetic (chamber) stages and whole foraminiferal test: Mg/Ca = (0.55(±0.03) - 0.0002(±4 × 10 -5) MSD) e 0.089T and, Mg/Ca = (0.55(±0.03) - 0.0001(±2 × 10 -5) MSD) e 0.089T, respectively, where MSD corresponds to the maximum shell diameter of the individual.

  7. Improving the Power Conversion Efficiency of Ultrathin Organic Solar Cells by Incorporating Plasmonic Effects of Spheroidal Metallic Nanoparticles

    E-print Network

    Park, Namkyoo

    Improving the Power Conversion Efficiency of Ultrathin Organic Solar Cells by Incorporating be exploited to achieve efficient harvesting of solar energy. Notably, the incorporation of plasmonic effects can allow the light harvesting capability of a solar cell to be maintained even as the thickness

  8. Effects of Pt incorporation on the isothermal oxidation behavior of chemical vapor deposition aluminide coatings

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Haynes, J. A.; Wright, G.; Pint, B. A.; Cooley, K. M.; Lee, W. Y.; Liaw, P. K.

    2001-07-01

    The effects of Pt incorporation on the isothermal oxidation and diffusion behavior of low-sulfur aluminide bond coatings were investigated. Aluminide (NiAl) coatings and Pt-modified aluminide (Ni,Pt)Al coatings were synthesized on a low-sulfur, yttrium-free single-crystal Ni-based superalloy by a high-purity, low-activity chemical vapor deposition (CVD) aluminizing procedure. The isothermal oxidation kinetics and scale adhesion behavior of CVD NiAl and (Ni,Pt)Al coatings before and after isothermal oxidation were determined by electron microprobe analysis. Platinum did not reduce oxide-scale growth kinetics. No significant differences in bulk refractory metal (W, Ta, Re, and Mo) distributions were observed as a result of Pt incorporation. Spallation of the alumina scale and the formation of large voids along the oxide-metal interface were commonly observed over the NiAl coating grain boundaries after 100 hours at 1150 °C. In contrast, no spallation of Al2O3 scales occurred on (Ni,Pt)Al coating surfaces or grain boundaries, although the sulfur content in the CVD (Ni,Pt)Al coatings was higher than that of the CVD NiAl coatings. Most significantly, no voids were observed at the oxide-metal interface on (Ni,Pt)Al coating surfaces or cross sections after 200 hours at 1150 °C. It was concluded that a major beneficial effect of Pt incorporation on an aluminide coatings oxidation resistance is the elimination of void growth at the oxide-metal interface, likely by mitigation of detrimental sulfur effects.

  9. A Model for Nonlinear Electrokinetics in Electric Field Guided Assembly of Colloids 

    E-print Network

    Steuber, James G.

    2011-02-22

    to characterize accurately forces and fluxes with linearized electrokinetic theory. The research presented in this dissertation describes an application of the finite element method to the nonlinear electrokinetic equations. The finite element model thus developed...

  10. Effect of cobalt incorporation and lithium enrichment in lithium nickel manganese oxides

    Microsoft Academic Search

    H. Deng; I. Belharouak; H. Wu; D. Dambournet; K. Amine

    2010-01-01

    Candidate cathode materials of cobalt-incorporated and lithium-enriched Li{sub (1+x)}Ni{sub 0.25}Co{sub 0.15}Mn{sub 0.6}O{sub (2.175+x\\/2)} (x=0.225-0.65) have been prepared by a coprecipitation method and a solid-state reaction. We systematically investigated the effect of both cobalt presence and lithium concentration on the structure, physical properties, and electrochemical behavior of the studied samples. The electrochemical performance of the cobalt-containing compounds showed much less dependence

  11. Effects of Pt incorporation on the isothermal oxidation behavior of chemical vapor deposition aluminide coatings

    Microsoft Academic Search

    Y. Zhang; J. A. Haynes; G. Wright; B. A. Pint; K. M. Cooley; W. Y. Lee; P. K. Liaw

    2001-01-01

    The effects of Pt incorporation on the isothermal oxidation and diffusion behavior of low-sulfur aluminide bond coatings were\\u000a investigated. Aluminide (NiAl) coatings and Pt-modified aluminide (Ni,Pt)Al coatings were synthesized on a low-sulfur, yttrium-free\\u000a single-crystal Ni-based superalloy by a high-purity, low-activity chemical vapor deposition (CVD) aluminizing procedure. The\\u000a isothermal oxidation kinetics and scale adhesion behavior of CVD NiAl and (Ni,Pt)Al coatings

  12. Effects of Pt incorporation on the isothermal oxidation behavior of chemical vapor deposition aluminide coatings

    Microsoft Academic Search

    Y. Zhang; J. A. Haynes; G. Wright; B. A. Pint; K. M. Cooley; W. Y. Lee; P. K. Liaw

    2001-01-01

    The effects of Pt incorporation on the isothermal oxidation and diffusion behavior of low-sulfur aluminide bond coatings were investigated. Aluminide (NiAl) coatings and Pt-modified aluminide (Ni,Pt)Al coatings were synthesized on a low-sulfur, yttrium-free single-crystal Ni-based superalloy by a high-purity, low-activity chemical vapor deposition (CVD) aluminizing procedure. The isothermal oxidation kinetics and scale adhesion behavior of CVD NiAl and (Ni,Pt)Al coatings

  13. Implementation of Electrokinetic-ISCO Remediation

    NASA Astrophysics Data System (ADS)

    Wu, M. Z.; Reynolds, D.; Fourie, A.; Prommer, H.; Thomas, D.

    2011-12-01

    Significant challenges remain in the remediation of low-permeability porous media (e.g. clays, silts) contaminated with dissolved and sorbed organic contaminants. Current remediation technologies, such as in-situ chemical oxidation (ISCO), are often ineffective and the treatment region is limited by very slow rates of groundwater flow (advection) or molecular diffusion. At the laboratory-scale several studies (e.g. Reynolds et al. 2008) have highlighted the potential for utilising electrokinetic transport, as induced by the application of an electric field, to deliver a remediation compound (e.g. permanganate, persulfate) within heterogeneous and low-permeability sediments for ISCO (termed EK-ISCO) or other treatments. Process-based numerical modelling of the coupled flow, transport and reaction processes can provide important insights into the prevailing controls and feedback mechanisms and therefore guide the optimisation of EK-ISCO remediation efficacy. In this study, a numerical model was developed that simulates groundwater flow and multi-species reactive transport under both hydraulic and electric gradients (Wu et al. 2010). Coupled into the existing, previously verified reactive transport model PHT3D (Prommer et al. 2003), the model was verified against analytical solutions and data from experimental studies. Using the newly developed model, the sensitivity of electrokinetic, hydraulic and engineering parameters as well as alternative configurations of the EK-ISCO treatment process were investigated. The duration and energy required for remediation was most dependent upon the applied voltage gradient and the natural oxidant demand and all investigated parameters affected the remediation process to some extent. Investigated variants of treatment configurations included several alternative locations for oxidant injection and a series of one-dimensional and two-dimensional electrode configurations.

  14. Electrokinetic Stretching of Tethered DNA

    PubMed Central

    Ferree, Sean; Blanch, Harvey W.

    2003-01-01

    During electrophoretic separations of DNA in a sieving medium, DNA molecules stretch from a compact coil into elongated conformations when encountering an obstacle and relax back to a coil upon release from the obstacle. These stretching dynamics are thought to play an important role in the separation mechanism. In this article we describe a silicon microfabricated device to measure the stretching of tethered DNA in electric fields. Upon application of an electric field, electro-osmosis generates bulk fluid flow in the device, and a protocol for eliminating this flow by attaching a polymer brush to all silicon oxide surfaces is shown to be effective. Data on the steady stretching of DNA in constant electric fields is presented. The data corroborate the approximate theory of hydrodynamic equivalence, indicating that DNA is not free-draining in the presence of both electric and nonelectric forces. Finally, these data provide the first quantitative test of a Stigter and Bustamante's detailed theory of electrophoretic stretching of DNA without adjustable parameters. The agreement between theory and experiment is good. PMID:14507716

  15. Behavior and anti-glioma effect of lapatinib-incorporated lipoprotein-like nanoparticles

    NASA Astrophysics Data System (ADS)

    Gao, Huile; Yang, Zhi; Cao, Shijie; Xi, Zhangjie; Zhang, Shuang; Pang, Zhiqing; Jiang, Xinguo

    2012-11-01

    The purpose of the investigation was to prepare a new type of nanoparticle, namely lapatinib-incorporated lipoprotein-like nanoparticles (LTNPs), and to evaluate the behavior and anti-glioma effect of LTNPs. LTNPs were prepared and characterized using the Cyro-transmission electron microscope (Cryo-TEM) and Raman scan methods. Cellular uptake and subcellular localization studies were performed to evaluate the in vitro behavior of LTNPs. An in vivo imaging technique was used for the evaluation of the targeting of LTNPs. To study the anti-glioma effect, glioma xenografts were used. The particle size of LTNPs was 92.6 nm, and the zeta potential was 28.40 mV. LTNPs contained a surface layer that was obviously different from the core, according to the Cryo-TEM analysis. A Raman scan analysis demonstrated the incorporation of lapatinib in LTNPs, and it also revealed a structure different from free lapatinib. The uptake of LTNP by U87 cells occurred in a concentration- and time-dependent manner. According to the subcellular study, the uptake of LTNPs was endosome mediated. LTNPs could distribute and accumulate in the tumor site by an enhanced permeation and retention effect. Both LTNPs (10 mg kg-1) and LTNPs (30 mg kg-1) could significantly inhibit the growth of U87 xenografts. For a similar antitumor effect, the required cumulative dose of LTNPs was only 5% compared to that of Tykerb (the commercial formulation of lapatinib). This study demonstrated the effective uptake of LTNPs by U87 cells, the passive targeting of LTNPs at tumors and the better antitumor effect of LTNPs.

  16. Electrokinetic Remediation. II. Amphoteric Metals and Enhancement with a Weak Acid

    Microsoft Academic Search

    David J. Wilson; José Miguel Rodríguez-Maroto; César Gómez-Lahoz

    1995-01-01

    A One-Dimensional Modl Is Developed For The Electrokinetic Treatment Of Aquifers Contaminated With An Ionic Salt. Electrokinetic Removal Of Amphoteric Metals Such As Zinc And Lead Is Simulated. The Use Of A Weak Acid (Acetic Acid) To Neutralize A Portion Of The Oh Generated Electrolytically In The Cathode Compartment Is Explored In Connection With The Electrokinetic Removal Of Nonamphoteric Metals

  17. Incorporation of quercetin in lipid microparticles: effect on photo- and chemical-stability.

    PubMed

    Scalia, Santo; Mezzena, Matteo

    2009-01-15

    Lipid microparticles loaded with the flavonoid, quercetin were developed in order to enhance its stability in topical formulations. The microparticles were produced using tristearin as the lipid material and phosphatidylcholine as the emulsifier. The obtained lipoparticles were characterized by release studies, scanning electron microscopy and powder X-ray diffractometry. The quercetin loading was 12.1% (w/w). Free or microencapsulated quercetin was introduced in a model cream formulation (oil-in-water emulsion) and irradiated with a solar simulator. The extent of photodegradation was measured by high-performance liquid chromatography. The light-induced decomposition of quercetin in the cream vehicle was markedly decreased by incorporation into the lipid microparticles (the extent of degradation was 23.1+/-3.6% for non-encapsulated quercetin compared to 11.9+/-2.5% for the quercetin-loaded microparticles) and this photostabilization effect was maintained over time. Moreover, the chemical instability of quercetin, during 3-month storage of the formulations at room temperature and in the dark, was almost completely suppressed by the lipid microparticle system. Therefore incorporation of quercetin in lipoparticles represents an effective strategy to enhance its stability in dermatological products. PMID:19042102

  18. Effect of Low-Level Laser Therapy on Incorporation of Block Allografts

    PubMed Central

    Valiati, Renato; Paes, Jefferson Viapiana; de Moraes, Aury Nunes; Gava, Aldo; Agostini, Michelle; Masiero, Anelise Viapiana; de Oliveira, Marilia Gerhardt; Pagnoncelli, Rogério Miranda

    2012-01-01

    Objective To assess the effect of low-level laser therapy (LLLT) on the incorporation of deep-frozen block allografts in a rabbit model. Background Data Studies have shown that LLLT has beneficial effects on tissue repair and new bone formation. Methods Bone tissue was harvested from two rabbits, processed by deep-freezing and grafted into the calvaria of 12 animals, which were then randomly allocated into two groups: experimental (L) and control (C). Rabbits in group L were irradiated with an aluminum gallium arsenide diode laser (AlGaAs; wavelength 830 nm, 4 J/cm2), applied to four sites on the calvaria, for a total dose of 16 J/cm2 per session. The total treatment dose after eight sessions was 128 J/cm2. Animals were euthanized at 35 (n = 6) or 70 days (n = 6) postoperatively. Results Deep-freeze-processed block allografts followed by LLLT showed incorporation at the graft-host interface, moderate bone remodeling, partial filling of osteocyte lacunae, less inflammatory infiltrate in the early postoperative period, and higher collagen deposition than the control group. Conclusion Optical microscopy and scanning electron microscopy showed that allograft bone processed by deep-freezing plus LLLT is suitable as an alternative for the treatment of bone defects. Use of the deep-freezing method for processing of bone grafts preserves the structural and osteoconductive characteristics of bone tissue. PMID:23155359

  19. Phosphorus incorporation during Si,,001...:P gas-source molecular beam epitaxy: Effects on growth kinetics and surface morphology

    E-print Network

    Spila, Timothy P.

    Phosphorus incorporation during Si,,001...:P gas-source molecular beam epitaxy: Effects on growth of Physics. DOI: 10.1063/1.2925798 I. INTRODUCTION Phosphorus is a common n-type dopant in Si-based mi

  20. Local reduced density matrix functional theory: incorporating static correlation effects in the Kohn-Sham equations

    E-print Network

    Lathiotakis, Nektarios N; Rubio, Angel; Gidopoulos, Nikitas I

    2014-01-01

    We propose a novel scheme to bring reduced density matrix functional theory (RDMFT) into the realm of density functional theory (DFT) that preserves the accurate density functional description at equilibrium, while incorporating accurately static and left-right correlation effects in molecules and keeping the good computational performance of DFT-based schemes. The key ingredient is to relax the requirement that the local potential is the functional derivative of the energy with respect to the density. Instead, we propose to restrict the search for the approximate natural orbitals within a domain where these orbitals are eigenfunctions of a single-particle hamiltonian with a local effective potential. In this way, fractional natural occupation numbers are accommodated into Kohn-Sham equations allowing for the description of molecular dissociation without breaking spin symmetry. Additionally, our scheme provides a natural way to connect an energy eigenvalue spectrum to the approximate natural orbitals and this...

  1. Removal of Cr(VI) from contaminated soil by electrokinetic remediation.

    PubMed

    Sawada, Akira; Mori, Ko-ichi; Tanaka, Shunitz; Fukushima, Masami; Tatsumi, Kenji

    2004-01-01

    A new process for the removal of hexavalent chromium [Cr(VI)] contaminated soil is described. The process provides for an efficient removal of anionic chemicals from contaminated soils. Chromate anions were removed from the soil to the anodic reservoir by the moving force of electromigration. In this process, the chromate anions that accumulate in the anodic reservoir are simultaneously eliminated by using a column packed adsorbent. The adsorbent (immobilized tannin) used was chemically incorporated into cellulose. Cr(VI) was found to be adsorbed to this adsorbent efficiently. In the electrokinetic process, the pH of the aqueous solution in the anodic reservoir was decreased by the electrolysis of water. In the present study, the pH of the solution in the anodic reservoir is maintained at pH 6 by the addition of an aqueous alkaline solution during the electrokinetic process. The advantage of pH control is that it promotes the release of Cr(VI) from the soil by electromigration, thus permitting the maximum adsorption of Cr(VI) on the immobilized tannin. Simultaneous collection of Cr(VI) from the anodic reservoir leads to the protection from secondary contamination with Cr(VI). PMID:15120432

  2. Probabilistic seismic hazard estimates incorporating site effects - An example from Indiana, U.S.A

    USGS Publications Warehouse

    Hasse, J.S.; Park, C.H.; Nowack, R.L.; Hill, J.R.

    2010-01-01

    The U.S. Geological Survey (USGS) has published probabilistic earthquake hazard maps for the United States based on current knowledge of past earthquake activity and geological constraints on earthquake potential. These maps for the central and eastern United States assume standard site conditions with Swave velocities of 760 m/s in the top 30 m. For urban and infrastructure planning and long-term budgeting, the public is interested in similar probabilistic seismic hazard maps that take into account near-surface geological materials. We have implemented a probabilistic method for incorporating site effects into the USGS seismic hazard analysis that takes into account the first-order effects of the surface geologic conditions. The thicknesses of sediments, which play a large role in amplification, were derived from a P-wave refraction database with over 13, 000 profiles, and a preliminary geology-based velocity model was constructed from available information on S-wave velocities. An interesting feature of the preliminary hazard maps incorporating site effects is the approximate factor of two increases in the 1-Hz spectral acceleration with 2 percent probability of exceedance in 50 years for parts of the greater Indianapolis metropolitan region and surrounding parts of central Indiana. This effect is primarily due to the relatively thick sequence of sediments infilling ancient bedrock topography that has been deposited since the Pleistocene Epoch. As expected, the Late Pleistocene and Holocene depositional systems of the Wabash and Ohio Rivers produce additional amplification in the southwestern part of Indiana. Ground motions decrease, as would be expected, toward the bedrock units in south-central Indiana, where motions are significantly lower than the values on the USGS maps.

  3. Reionization on Large Scales. IV. Predictions for the 21 cm Signal Incorporating the Light Cone Effect

    NASA Astrophysics Data System (ADS)

    La Plante, P.; Battaglia, N.; Natarajan, A.; Peterson, J. B.; Trac, H.; Cen, R.; Loeb, A.

    2014-07-01

    We present predictions for the 21 cm brightness temperature power spectrum during the Epoch of Reionization (EoR). We discuss the implications of the "light cone" effect, which incorporates evolution of the neutral hydrogen fraction and 21 cm brightness temperature along the line of sight. Using a novel method calibrated against radiation-hydrodynamic simulations, we model the neutral hydrogen density field and 21 cm signal in large volumes (L = 2 Gpc h -1). The inclusion of the light cone effect leads to a relative decrease of about 50% in the 21 cm power spectrum on all scales. We also find that the effect is more prominent at the midpoint of reionization and later. The light cone effect can also introduce an anisotropy along the line of sight. By decomposing the 3D power spectrum into components perpendicular to and along the line of sight, we find that in our fiducial reionization model, there is no significant anisotropy. However, parallel modes can contribute up to 40% more power for shorter reionization scenarios. The scales on which the light cone effect is relevant are comparable to scales where one measures the baryon acoustic oscillation. We argue that due to its large comoving scale and introduction of anisotropy, the light cone effect is important when considering redshift space distortions and future application to the Alcock-Paczy?ski test for the determination of cosmological parameters.

  4. Separation of hydrophobic polymer additives by microemulsion electrokinetic chromatography.

    PubMed

    Hilder, E F; Klampfl, C W; Buchberger, W; Haddad, P R

    2001-07-13

    Microemulsion electrokinetic chromatography (MEEKC) has been applied to the separation of some phenolic antioxidants [Irganox 1024, Irganox 1035, Irganox 1076, Irganox 1010, Irganox 1330, Irgafos 138, Irganox 168 and 2,6-di-tert.-butyl-4-methylphenol (BHT)]. Due to the extremely hydrophobic nature of these analytes, they could not be separated using standard MEEKC conditions and two alternative approaches were investigated. Using an acidic buffer (phosphate, pH 2.5) to effectively suppress the electroosmotic flow, the addition of 2-propanol to the aqueous phase of the microemulsion buffer to improve partitioning of the analytes, and a negative separation voltage, separation of five of the analytes in under 10 min was possible. The second approach, using a basic buffer (borate, pH 9.2) and a positive separation voltage resulted in complete resolution of all eight analytes. A mixed surfactant system comprising the anionic sodium dodecyl sulfate (SDS) and neutral Brij 35 was used to reduce the overall charge and with it the mobility of the droplets, and hence the separation time. Using an optimised MEEKC buffer consisting of 2.25% (w/w) SDS, 0.75% (w/w) Brij 35, 0.8% (w/w) n-octane, 6.6% (w/w) 1-butanol, 25% (w/w) 2-propanol and 64.6% (w/w) 10 mM borate buffer (pH 9.2) the eight target analytes were baseline separated in under 25 min. For these analytes, MEEKC was found to be superior to micellar electrokinetic chromatography in every respect. Specifically, the solubility of the analytes was better, the selectivity was more favourable, the analysis time was shorter and the separation efficiency was up to 72% higher when using the MEEKC method. Detection limits from 5.4 to 26 microg/ml were obtained and the calibration plot was linear over more than one order of magnitude. The optimised method could be applied to the determination of Irganox 1330 and Irganox 1010 in polypropylene. PMID:11486875

  5. Effect of incorporation of fermented bamboo shoot on physicochemical and microbial quality of pork pickle.

    PubMed

    Chavhan, D M; Hazarika, M; Brahma, M L; Hazarika, R A; Rahman, Z

    2015-02-01

    Replacement of commercial chemical preservative (Vinegar) by incorporating fermented bamboo shoot (FBS) products partially or completely and their effect on physicochemical, microbial and shelf life qualities on pork pickle products was studied. Different FBS products such as FBS extract, paste and powder were incorporated in the pork pickle products at the level of 50 to 100 % with or without vinegar and stored at room temperature for 90 days. Highest pH values and lowest titrable acidity was recorded in products with 50 and 100 % FBS powder. No significant differences were observed with respect to proximate composition i.e. percent moisture, protein, fat and ash contents among the products except the product with 100 % FBS powder which had significantly (p?

  6. A new Bernoulli-Euler beam model incorporating microstructure and surface energy effects

    NASA Astrophysics Data System (ADS)

    Gao, X.-L.; Mahmoud, F. F.

    2014-04-01

    A new Bernoulli-Euler beam model is developed using a modified couple stress theory and a surface elasticity theory. A variational formulation based on the principle of minimum total potential energy is employed, which leads to the simultaneous determination of the equilibrium equation and complete boundary conditions for a Bernoulli-Euler beam. The new model contains a material length scale parameter accounting for the microstructure effect in the bulk of the beam and three surface elasticity constants describing the mechanical behavior of the beam surface layer. The inclusion of these additional material constants enables the new model to capture the microstructure- and surface energy-dependent size effect. In addition, Poisson's effect is incorporated in the current model, unlike existing beam models. The new beam model includes the models considering only the microstructure dependence or the surface energy effect as special cases. The current model reduces to the classical Bernoulli-Euler beam model when the microstructure dependence, surface energy, and Poisson's effect are all suppressed. To demonstrate the new model, a cantilever beam problem is solved by directly applying the general formulas derived. Numerical results reveal that the beam deflection predicted by the new model is smaller than that by the classical beam model. Also, it is found that the difference between the deflections predicted by the two models is very significant when the beam thickness is small but is diminishing with the increase of the beam thickness.

  7. General electrokinetic model for concentrated suspensions in aqueous electrolyte solutions: Electrophoretic mobility and electrical conductivity in static electric fields.

    PubMed

    Carrique, Félix; Ruiz-Reina, Emilio; Roa, Rafael; Arroyo, Francisco J; Delgado, Ángel V

    2015-10-01

    In recent years different electrokinetic cell models for concentrated colloidal suspensions in aqueous electrolyte solutions have been developed. They share some of its premises with the standard electrokinetic model for dilute colloidal suspensions, in particular, neglecting both the specific role of the so-called added counterions (i.e., those released by the particles to the solution as they get charged), and the realistic chemistry of the aqueous solution on such electrokinetic phenomena as electrophoresis and electrical conductivity. These assumptions, while having been accepted for dilute conditions (volume fractions of solids well below 1%, say), are now questioned when dealing with concentrated suspensions. In this work, we present a general electrokinetic cell model for such kind of systems, including the mentioned effects, and we also carry out a comparative study with the standard treatment (the standard solution only contains the ions that one purposely adds, without ionic contributions from particle charging or water chemistry). We also consider an intermediate model that neglects the realistic aqueous chemistry of the solution but accounts for the correct contribution of the added counterions. The results show the limits of applicability of the classical assumptions and allow one to better understand the relative role of the added counterions and ions stemming from the electrolyte in a realistic aqueous solution, on electrokinetic properties. For example, at low salt concentrations the realistic effects of the aqueous solution are the dominant ones, while as salt concentration is increased, it is this that progressively takes the control of the electrokinetic response for low to moderate volume fractions. As expected, if the solids concentration is high enough the added counterions will play the dominant role (more important the higher the particle surface charge), no matter the salt concentration if it is not too high. We hope this work can help in setting up the real limits of applicability of the standard cell model for concentrated suspensions by a quantitative analysis of the different effects that have been classically disregarded, showing that in many cases they can be determinant to get rigorous predictions. PMID:26051031

  8. Micellar electrokinetic chromatography of organic and peroxide-based explosives.

    PubMed

    Johns, Cameron; Hutchinson, Joseph P; Guijt, Rosanne M; Hilder, Emily F; Haddad, Paul R; Macka, Mirek; Nesterenko, Pavel N; Gaudry, Adam J; Dicinoski, Greg W; Breadmore, Michael C

    2015-05-30

    CE methods have been developed for the analysis of organic and peroxide-based explosives. These methods have been developed for deployment on portable, in-field instrumentation for rapid screening. Both classes of compounds are neutral and were separated using micellar electrokinetic chromatography (MEKC). The effects of sample composition, separation temperature, and background electrolyte composition were investigated. The optimised separation conditions (25mM sodium tetraborate, 75mM sodium dodecyl sulfate at 25°C, detection at 200nm) were applied to the separation of 25 organic explosives in 17min, with very high efficiency (typically greater than 300,000 platesm(-1)) and high sensitivity (LOD typically less than 0.5mgL(-1); around 1-1.5?M). A MEKC method was also developed for peroxide-based explosives (10mM sodium tetraborate, 100mM sodium dodecyl sulfate at 25°C, detection at 200nm). UV detection provided LODs between 5.5 and 45.0mgL(-1) (or 31.2-304?M), which is comparable to results achieved using liquid chromatography. Importantly, no sample pre-treatment or post-column reaction was necessary and the peroxide-based explosives were not decomposed to hydrogen peroxide. Both MEKC methods have been applied to pre-blast analysis and for the detection of post-blast residues recovered from controlled, small scale detonations of organic and peroxide-based explosive devices. PMID:25998463

  9. Electrokinetic particle-electrode interactions at high frequencies

    NASA Astrophysics Data System (ADS)

    Yariv, Ehud; Schnitzer, Ory

    2013-01-01

    We provide a macroscale description of electrokinetic particle-electrode interactions at high frequencies, where chemical reactions at the electrodes are negligible. Using a thin-double-layer approximation, our starting point is the set of macroscale equations governing the “bounded” configuration comprising of a particle suspended between two electrodes, wherein the electrodes are governed by a capacitive charging condition and the imposed voltage is expressed as an integral constraint. In the large-cell limit the bounded model is transformed into an effectively equivalent “unbounded” model describing the interaction between the particle and a single electrode, where the imposed-voltage condition is manifested in a uniform field at infinity together with a Robin-type condition applying at the electrode. This condition, together with the standard no-flux condition applying at the particle surface, leads to a linear problem governing the electric potential in the fluid domain in which the dimensionless frequency ? of the applied voltage appears as a governing parameter. In the high-frequency limit ??1 the flow is dominated by electro-osmotic slip at the particle surface, the contribution of electrode electro-osmosis being O(?-2) small. That simplification allows for a convenient analytical investigation of the prevailing case where the clearance between the particle and the adjacent electrode is small. Use of tangent-sphere coordinates allows to calculate the electric and flows fields as integral Hankel transforms. At large distances from the particle, along the electrode, both fields decay with the fourth power of distance.

  10. ELECTROKINETIC MEMBRANE PROCESSES IN RELATION TO PROPERTIES OF EXCITABLE TISSUES

    PubMed Central

    Teorell, Torsten

    1959-01-01

    A quantitative theory is presented for the behavior of a membrane-electrolyte system subject to an electric current flow (the "membrane oscillator"). If the membrane is porous, carries "fixed charges," and separates electrolyte solutions of different conductances, it can be the site of repetitive oscillatory changes in the membrane potential, the membrane resistance, and the hydrostatic pressure difference across the membrane. These events are accompanied by a pulsating transport of bulk solutions. The theory assumes the superposition of electrochemical and hydrostatic gradients and centers round the kinetics of resistance changes within the membrane, as caused by effects from diffusion and electro-osmotic fluid streaming. The results are laid down in a set of five simple, basic expressions, which can be transformed into a pair of non-linear differential equations yielding oscillatory solutions. A graphical integration method is also outlined (Appendix II). The agreement between the theory and previous experimental observations is satisfactory. The applied electrokinetic concepts may have importance in relation to analyses of the behavior of living excitable cells or tissues. PMID:13631208

  11. Incorporating Latest Technologies in a Cost-Effective Design of Rainfall Catchment and Filtration Systems for Coastal Rhode Island Communities

    E-print Network

    Rhode Island, University of

    Incorporating Latest Technologies in a Cost-Effective Design of Rainfall Catchment and Filtration Latest Technologies in a Cost-Effective Design of Rainfall Catchment and Filtration Systems for Coastal household water usage requirements. The system must be cost-effective, easy to install and maintain

  12. Incorporating Complex Sample Design Effects When Only Final Survey Weights are Available

    PubMed Central

    West, Brady T.; McCabe, Sean Esteban

    2012-01-01

    This article considers the situation that arises when a survey data producer has collected data from a sample with a complex design (possibly featuring stratification of the population, cluster sampling, and / or unequal probabilities of selection), and for various reasons only provides secondary analysts of those survey data with a final survey weight for each respondent and “average” design effects for survey estimates computed from the data. In general, these “average” design effects, presumably computed by the data producer in a way that fully accounts for all of the complex sampling features, already incorporate possible increases in sampling variance due to the use of the survey weights in estimation. The secondary analyst of the survey data who then 1) uses the provided information to compute weighted estimates, 2) computes design-based standard errors reflecting variance in the weights (using Taylor Series Linearization, for example), and 3) inflates the estimated variances using the “average” design effects provided is applying a “double” adjustment to the standard errors for the effect of weighting on the variance estimates, leading to overly conservative inferences. We propose a simple method for preventing this problem, and provide a Stata program for applying appropriate adjustments to variance estimates in this situation. We illustrate two applications of the method to survey data from the Monitoring the Future (MTF) study, and conclude with suggested directions for future research in this area. PMID:24596541

  13. Evaluation of electrode configuration and mode of DC power for improvement of electrokinetic soil remediation

    NASA Astrophysics Data System (ADS)

    Kim, Soon-Oh; Lee, Woo Chun; Lee, Sang Woo; Lee, Byung-Tae

    2014-05-01

    Electrokinetic soil remediation is also called electrokinetic soil processing, electroreclamation, and electrochemical decontamination. The electrokinetic technique needs a low-level direct current of the order of mA/cm2 between electrodes to remove contaminants. The electrokinetic technique is one of the most promising remediation processes, and offers high efficiency and time effectiveness in the decontamination of low-permeability soils contaminated with heavy metals, radionuclides, or organic compounds. The significance of this technique is attributed to its low operational cost and potential applicability to a wide range of contaminant types, and these benefits have resulted in the initiation of numerous studies into its use for waste remediation. Electrode configuration is crucial for cost-effectiveness and overall efficacy of the elelectrokinetic processing, particularly in its field implementation. We investigated the effectiveness of various electrode arrays which can be grouped into one-dimensional (1-D) and two-dimensional (2-D) ones. Normally, the DC electricity of full wave has been used to remove contaminants from soils using elelectrokinetic processing. However, application of half-wave DC power can be also taken into account to improve efficacy of the processing, because it generates pulse power and accelerates the migration of contaminants within soils. We empirically evaluated the effect of type of DC electricity on the overall performance of the electrokinetic soil processing. The 1-D configuration with 5 electrode pairs showed the least total electric power, but that consumed in only the soil cell was less in the 2-D arrays than in 1-D ones. Particularly, most of the electric power is likely to be consumed in the electrode compartments, and the electric resistance in the electrode parts should be reduced to save the electric energy cost in the whole processing. In terms of removal efficiencies of 5 heavy metal contaminants, overall efficiency was higher in the 2-D arrays than in the 1-D ones, and it is caused by the fact that the migration of heavy metals is enhanced towards cathode in the 2-D configuration because the current density increases in that direction due to nonlinear electric fields. Comparing removal efficiencies between Cu and Pb, the half-wave DC seems to be more effective in removing Pb, whereas Cu was more efficiently removed by the full-wave DC than by the half-wave DC power. This difference is likely to be caused by the two coupled reasons: difference in chemical fractionations of two heavy metals and difference in features between two kinds of DC electricity. The results suggest that the types of DC electric power as well as combination between them should be evaluated to improve overall efficacy and economy of whole electrokinetic processing for soil remediation.

  14. Method for eliminating gas blocking in electrokinetic pumping systems

    DOEpatents

    Arnold, Don W. (Livermore, CA); Paul, Phillip H. (Livermore, CA); Schoeniger, Joseph S. (Oakland, CA)

    2001-09-11

    A method for eliminating gas bubble blockage of current flow during operation of an electrokinetic pump. By making use of the ability to modify the surface charge on the porous dielectric medium used in electrokinetic pumps, it becomes possible to place electrodes away from the pressurized region of the electrokinetic pump. While gas is still generated at the electrodes they are situated such that the generated gas can escape into a larger buffer reservoir and not into the high pressure region of the pump where the gas bubbles can interrupt current flow. Various combinations of porous dielectric materials and ionic conductors can be used to create pumps that have desirable electrical, material handling, and flow attributes.

  15. Transport of radioactive ions in soil by electrokinetics

    SciTech Connect

    Buehler, M.F.; Surma, J.E.; Virden, J.W.

    1994-10-01

    An electrokinetic approach is being evaluated for in situ soil remediation at the Hanford Site in Richland, Washington. This approach uses an applied electric field to induce transport of both radioactive and hazardous waste ions in soil. The work discussed in this paper involves the development of a new method to monitor the movement of the radioactive ions within the soil during the electrokinetic process. A closed cell and a gamma counter were used to provide iii situ measurements of {sup 137}Cs and {sup 60}Co movement in Hanford soil. Preliminary results show that for an applied potential of 200 V over approximately 200 hr, {sup 137}Cs and {sup 60}60 were transported a distance of 4 to 5 in. The monitoring technique demonstrated the feasibility of using electrokinetics for soil separation applications.

  16. Bile salt surfactants in micellar electrokinetic capillary chromatography: Application to hydrophobic molecule separations

    SciTech Connect

    Cole, R.O.; Sepaniak, M.J. (Tennessee Univ., Knoxville, TN (USA). Dept. of Chemistry); Hinze, W.L. (Wake Forest Univ., Winston-Salem, NC (USA). Dept. of Chemistry); Gorse, J.; Oldiges, K. (Baldwin-Wallace Coll., Berea, OH (USA). Dept. of Chemistry)

    1990-01-01

    Bile Salt surfactants are used in the micellar electrokinetic capillary chromatography (MECC) separation of various hydrophobic compounds. The use of methanol in the mobile phase allows the separation of previously intractable compounds including polyaromatic hydrocarbons. The effects of methanol on critical micelle concentration is investigated for sodium dodecyl sulfate (SDS) and the bile salt sodium cholate. It is determined that the unique structure of the bile salt micelle is much more tolerant to the addition of organic solvents than SDS, thereby increasing the scope of applications of MECC to include hydrophobic compounds. 30 refs., 9 figs.

  17. Fast Myoglobin Detection Using Nanofluidic Electrokinetic Trapping Technique

    NASA Astrophysics Data System (ADS)

    Chun, DongWon; Kim, Sang Hui; Song, Hyungwan; Kwak, Seungmin; Kim, YooChan; Seok, HyunGwang; Lee, Sang-Myung; Lee, Jeong Hoon

    2013-01-01

    We report on the preconcentration-enhanced fast collection of myoglobin protein for the rapid detection of myocardial infarction. We use a one-dimensional micro/nanofluidic chip for electrokinetic preconcentration and demonstrate that the preconcentration factor of 1 ng/ml Alexa Fluor 488-labeled myoglobin is ˜1000 within 200 s, where the protein had a weak negative charge, thereby making it hard to perform electrokinetic trapping for neutral-like proteins. The potential feasibility with new assay strategies for use in a rapid immunoassay screening test for myocardial infarction is discussed.

  18. [Effect of the mode of incorporation of lucerne serum on digestibility and microbial activity in the rumen].

    PubMed

    Fassih, A; Cordelet, C; Faurie, F; Tisserand, J L

    1988-01-01

    The extraction of protein from lucerne produces some liquid residue (called lucerne serum), the effects of which were studied on rumen microbial activity in 6 adult fistulated wethers. The introduction of the serum directly into the rumen stimulated cellulolytic activity whereas its incorporation into the lucerne solid residue before dehydration seemed to have no effect. PMID:3254603

  19. A Risk Prediction Algorithm for Ovarian Cancer Incorporating BRCA1, BRCA2, Common Alleles and Other Familial Effects

    E-print Network

    Jervis, Sarah; Song, Honglin; Lee, Andrew; Dicks, Ed; Harrington, Patricia; Baynes, Caroline; Manchanda, Ranjit; Easton, Douglas F.; Jacobs, Ian; Pharoah, Paul P. D.; Antoniou, Antonis C.

    2015-05-29

    factors in Cancer Heredity (SEARCH), and segregation analysis methods to develop genetic models for OvC that incorporate the effects of BRCA1 and BRCA2 muta- tions and model the residual familial aggregation to OvC. The explicit effects of 17 common Ov...

  20. Effect of prehydrogenation on hydroconversion of Maya residuum: Part 2, Hydrogen incorporation

    SciTech Connect

    Beret, S.; Reynolds, J.G.

    1988-01-19

    Maya 650/sup 0/F residuum (Maya AR) was prehydrogenated over a standard hydroprocessing catalyst. The 650/sup 0/F residuum of this product (HMaya AR) and Maya AR were then separately hydroprocessed further at selected conditions. The products were examined by elemental, /sup 1/H, and /sup 13/C NMR analyses. For all processing steps, hydrogen was incorporated in capping fragments formed during cracking reactions, as well as in hydrogenation reactions, heteroatom removal, and hydrocarbon gas formation, but the distribution of the hydrogen was dependent upon the type and severity of the process. For the direct hydroconversion of Maya AR, 25 to 30% of the total hydrogen was incorporated for heteroatom removal and hydrocarbon gas formation. The remaining hydrogen was incorporated in hydrogenation and cracking reactions. For the two-step hydroconversion process, 30 to 40% of the total hydrogen was incorporated for heteroatom removal and hydrocarbon gas formation. The remaining was primarily incorporated in hydrogenation reactions. Some was incorporated into cracking reactions in the moderate severity case, but none was seen in the low severity case. The hydrogen incorporation during each specific processing step is discussed, along with an evaluation of the prehydrogenation step as a residuum conversion process option. These results will be also compared to previously reported hydrogen incorporation measurements on other feeds and processing methods. 8 figs., 8 tabs.

  1. Influence of scale on electrostatic forces and torques in AC particulate electrokinetics.

    PubMed

    Jones, T B

    2003-11-01

    Dielectrophoretic forces and torques move and manipulate biological cells, typically of the order of 10 mum ( approximately 10(-5) m) in diameter and ordinarily suspended in aqueous liquids, using electrodes with dimensions around 100 mum ( approximately 10(-4) m). The ability to exploit these same electromechanical effects for particles below 1 mum, that is, <10(-6) m, creates opportunities for remote manipulation and handling of subcellular components, biological macromolecules, and DNA. In this paper, Trimmer's bracket notation is adapted for systematic examination of the scaling laws governing electrokinetic behaviour. The purpose is to shed light on how critical performance measures relevant to the laboratory on a chip are affected by reducing particle sizes and electrode dimensions into the nanometre range. The scaling methodology facilitates consideration of the effect of electrode structure and particle size reduction on voltage, electric field, heating, and response time. Particles with induced moments, dipolar and quadrupolar, as well as permanent dipoles are examined. Separate consideration is given to electrical torque and its application in electrorotation and particle alignment. An eventual goal of these scaling studies is to identify the lower limit on the size of particles that can be manipulated effectively using electrokinetic phenomena. PMID:16468929

  2. PROOF COPY 072415JAP Electrokinetic micropump and micromixer design based

    E-print Network

    Chang, Hsueh-Chia

    PROOF COPY 072415JAP PROOF COPY 072415JAP Electrokinetic micropump and micromixer design based.1063/1.1767286] I. INTRODUCTION Because mechanical micropumps with moving parts are prone to frictional wear be nonuniform such that vortices are created. Hence, both dc micropumps and dc micromixers can be fabricated

  3. PhD thesis, s971820 AC Electrokinetic micropumps

    E-print Network

    PhD thesis, s971820 AC Electrokinetic micropumps Laurits Højgaard Olesen ++++++++ V0 cos(t) Fluid- ular, we focus on a theoretical description of AC electroosmotic micropumps with asymmetric electrode for experimental micropump geometries and display contributions to the net pumping velocity from the different flow

  4. Influence of Surface Heterogeneity on Electrokinetically Driven Microfluidic Mixing

    E-print Network

    Erickson, David

    mixing in electroosmotic flow systems is inherently diffusion dominated, requiring both a long mixingInfluence of Surface Heterogeneity on Electrokinetically Driven Microfluidic Mixing David Erickson Electroosmotic flow in microfluidic systems is limited to the low Reynolds number regime. As a result species

  5. Physicochemical soil-contaminant interactions during electrokinetic extraction

    Microsoft Academic Search

    Albert T. Yeung; Cheng-non Hsu; Rajendra M. Menon

    1997-01-01

    The feasibility of using electrokinetics to extract contaminants from soils has been established by bench-scale laboratory experiments and small-scale field tests. However, the physics and chemistry associated with the innovative remediation technology are not yet fully understood. Many physicochemical reactions occur simultaneously during the process. These reactions may enhance or reduce the cleanup efficiency of the process. They are particularly

  6. Capillary electrokinetic separations: Influence of mobile phase composition on performance

    SciTech Connect

    Sepaniak, M.J.; Swaile, D.F.; Powell, A.C.; Cole, R.O.

    1990-01-01

    The composition of the mobile phase employed in capillary zone electrophoresis and the related technique, micellar electrokinetic capillary chromatography, is an important factor in determining separation performance. The influences of ionic salt, surfactant, and organic solvent mobile phase additives on separation efficiency, retention, and elution range are discussed and demonstrated. 23 refs., 2 figs., 2 tabs.

  7. Effect of polymer microsphere incorporation on impact performance of STF cotton fabric composite

    NASA Astrophysics Data System (ADS)

    Suhaimi, M. S.; Mohamed, R.; Faiza, M. A.

    2010-05-01

    Liquid body armor system is recently being used compared to conventional body armor due to its lightweight, highly flexibility and reduced layered fabric. Shear thickening fluid (STF) system comprising of Polymer Microsphere (PMS) and solvent media are exploited in this study. Polymer Microsphere (eg: PMS) in solvent media varies with viscosity upon different PMS composition with and without surfactant. Fabrication of STF fabric system using Cotton laminate were performed using hand lay up with fixed areal density of 40% PMS content. Impact performance was evaluated using knife pendulum impact tester. Impact strength was found to increase with incorporation of STF system. STF addition significantly improves stab resistance of fabric. There were improvements of impact energy absorption for cotton fabric at different volume of STF used with 3 layers. For the three layer systems, impact performance showed improvement of 27.62% using 4ml of STF compared to use of 8ml of STF (12.44% impact improvement). For Cotton STF fabric composite, the effectiveness of the penetration was raised upon higher fabric layers. Overall, the STF-Cotton fabric composite are totally failure during testing, because of the cotton fabric is a fabric, which has very low strength. The addition of STF onto the cotton fabric system will not make the fabric becomes highly impact resistance.

  8. Effect of incorporating sugar beet pulp in the finisher diet on performance of geese.

    PubMed

    Arroyo, J; Brachet, M; Dubois, J P; Lavigne, F; Molette, C; Bannelier, C; Fortun-Lamothe, L

    2015-04-01

    The aim of this work was to study the effects of incorporating sugar beet pulp (SBP) into the diet on the development of the crop and performance of geese. A total of 480 1-day-old ganders were divided into three groups differing in the composition and mode of distribution of the diet offered from day 56 to 89. The following two diets were used: a standard diet (nitrogen-corrected apparent metabolizable energy, AMEn 11.44 MJ/kg; 160 g/kg CP) or a diet containing 10% of SBP (SBP diet; AMEn 11.47 MJ/kg; 160 g/kg CP). The swelling capacity (SC) hydration was higher for SBP than for the standard diet (3.62 v. 2.72 ml of H2O/g of dry matter at 60 min; P<0.05). In the Control group, birds were fed with a controlled time of access to a standard diet. Other birds were fed the SBP diet with a controlled time of access (SBPt group) or a controlled quantity offered (SBPq). From day 90 to 104, 88 birds/group were overfed with a mixture containing mainly corn. Body traits including volume of the crop were measured at day 89. Fatty liver weight and commercial grading were measured at d 104. Feed intake from day 56 to 89 was higher in the Control group than in the SBPt group (8097 v. 7545 g; P<0.05), feed intake in the SBPq group being intermediate (7801 g); however, live weights (LW) of the birds were similar in the three groups measured at day 89 (5746 g; P>0.05). At day 89, the volume of the crop tended to be higher in the SBPt compared with the Control group (52.8 v. 48.8 ml/kg of LW; P=0.101). After overfeeding, feed intake (12 922 g), weight gain (2412 g), LW (8170 g), fatty liver weight (875 g) and commercial grading of the fatty liver were similar (P>0.1) for all the three groups. Therefore, SBP could help adapt the digestive tract of waterfowl to high feed intake through an increase in the crop volume, but its method of use - that is, level of incorporation and mode of distribution - should continue to be investigated. PMID:25434525

  9. Effect of Chitosan Incorporation and Scaffold Geometry on Chondrocyte Function in Dense Collagen Type I Hydrogels

    PubMed Central

    Chicatun, Florencia; Pedraza, Claudio E.; Muja, Naser; Ghezzi, Chiara E.; McKee, Marc D.

    2013-01-01

    Tissue engineering approaches for articular cartilage (AC) repair using collagen type I (Coll)-based hydrogels are limited by their low collagen fibril density (CFD; <0.5?wt%) and their poor capacity to support chondrocyte differentiation. Chitosan (CTS) is a well-characterized polysaccharide that mimics the glycosaminoglycans (GAGs) present in native AC extracellular matrix and exhibits chondroprotective properties. Here dense Coll/CTS hydrogel discs (16?mm diameter, 140–250??m thickness) with CFD (?6?wt%) approaching that of AC were developed to investigate the effect of CTS content on the growth and differentiation of three-dimensionally seeded RCJ3.1C5.18 chondroprogenitor cells. Compared to dense Coll alone, cells seeded within Coll/CTS showed increased viability and metabolic activity, as well as a decrease in cell-mediated gel contraction. Immunohistochemistry for collagen type II, in combination with Safranin O staining and GAG quantification, indicated greater chondroprogenitor differentiation within Coll/CTS, compared to cells seeded within Coll alone. The complex interplay between scaffold geometry, microstructure, composition, mechanical properties and cell function was further evaluated by rolling dense planar sheets to prepare cylindrically shaped constructs having clinically relevant diameters (3–5?mm diameter, 9?mm height). The compressive modulus of the cylindrically shaped constructs decreased significantly after 7 days in culture, and remained unchanged up to 21 days for each scaffold composition. Unlike Coll, cells seeded within Coll/CTS showed greater viability along the entire radial extent of the cylindrical rolls and increased GAG production at each time point. While GAG content decreased over time and reduced cell viability was observed within the core region of all cylindrical rolls, the incorporation of CTS diminished both these effects. In summary, these findings provide insight into the challenges involved when scaling up scaffolds designed and optimised in vitro for tissue repair. PMID:23859275

  10. Effect of chitosan incorporation and scaffold geometry on chondrocyte function in dense collagen type I hydrogels.

    PubMed

    Chicatun, Florencia; Pedraza, Claudio E; Muja, Naser; Ghezzi, Chiara E; McKee, Marc D; Nazhat, Showan N

    2013-12-01

    Tissue engineering approaches for articular cartilage (AC) repair using collagen type I (Coll)-based hydrogels are limited by their low collagen fibril density (CFD; <0.5?wt%) and their poor capacity to support chondrocyte differentiation. Chitosan (CTS) is a well-characterized polysaccharide that mimics the glycosaminoglycans (GAGs) present in native AC extracellular matrix and exhibits chondroprotective properties. Here dense Coll/CTS hydrogel discs (16?mm diameter, 140-250??m thickness) with CFD (?6?wt%) approaching that of AC were developed to investigate the effect of CTS content on the growth and differentiation of three-dimensionally seeded RCJ3.1C5.18 chondroprogenitor cells. Compared to dense Coll alone, cells seeded within Coll/CTS showed increased viability and metabolic activity, as well as a decrease in cell-mediated gel contraction. Immunohistochemistry for collagen type II, in combination with Safranin O staining and GAG quantification, indicated greater chondroprogenitor differentiation within Coll/CTS, compared to cells seeded within Coll alone. The complex interplay between scaffold geometry, microstructure, composition, mechanical properties and cell function was further evaluated by rolling dense planar sheets to prepare cylindrically shaped constructs having clinically relevant diameters (3-5?mm diameter, 9?mm height). The compressive modulus of the cylindrically shaped constructs decreased significantly after 7 days in culture, and remained unchanged up to 21 days for each scaffold composition. Unlike Coll, cells seeded within Coll/CTS showed greater viability along the entire radial extent of the cylindrical rolls and increased GAG production at each time point. While GAG content decreased over time and reduced cell viability was observed within the core region of all cylindrical rolls, the incorporation of CTS diminished both these effects. In summary, these findings provide insight into the challenges involved when scaling up scaffolds designed and optimised in vitro for tissue repair. PMID:23859275

  11. Effects of oxygen incorporation in GeSbTe films on electrical properties and thermal stability

    NASA Astrophysics Data System (ADS)

    Jang, Moon Hyung; Park, Seung Jong; Lim, Dong Hyeok; Park, Sung Jin; Cho, Mann-Ho; Cho, Seong Jin; Cho, Yoon Ho; Lee, Jong-Heun

    2010-03-01

    Oxygen incorporated Ge2Sb2Te5 (GST) films were prepared by an ion beam sputtering deposition method. I-V curves of the oxygen incorporated GST active layer showed that the threshold voltage (Vth) varied, depending on the level of incorporated oxygen. In the case of a GST film with an elevated oxygen content of 30.8%, the GST layer melted at 9.02 V due to the instability conferred by the high oxygen content. The formation of Ge-deficient hexagonal phases such as GeSb2Te4 and Sb2Te3 appear to be responsible for the Vth variation. Impedance analyses indicated that the resistance in GST films with oxygen contents of 16.7% and 21.7% had different origins. Thermal desorption spectroscopy data indicate that moisture and hydrocarbons were more readily desorbed at higher oxygen content because the oxygen incorporated GST films are more hydrophilic than undoped GST films.

  12. Effect of prehydrogenation on hydroconversion of Maya residuum; Part II: Hydrogen incorporation

    SciTech Connect

    Beret, S. (Chevron Research Co., Richmond, CA (USA))

    1990-04-01

    Maya 650{sup 0}F residuum (Maya AR) was prehydrogenated over a standard hydroprocessing catalyst. The 650{sup 0}F residuum of this product (HMaya AR) and Maya AR were then separately hydroprocessed further at selected conditions. The products were examined by elemental, {sup 1}H and {sup 13}C NMR analyses to determine the how hydrogen was incorporated during processing. For all processing steps, hydrogen was incorporated in capping fragments formed during cracking reactions, as well as in hydrogenation reactions, heteroatom removal, and hydrocarbon gas formation, but the distribution of the hydrogen was dependent upon the type and severity of the process. For the direct hydroconversion of Maya AR, 25 to 30% of the total hydrogen was incorporated for heteroatom removal and hydrocarbon gas formation. The remaining hydrogen was incorporated in hydrogenation and cracking reactions. The hydrogen incorporation during each specific processing step is discussed, along with an evaluation of the prehydrogenation step as a residuum conversion process option. These results are compared to previously reported hydrogen incorporation measurements on other feeds and processing methods.

  13. Incorporating the Effects of 3D Radiative Transfer in the Presence of Clouds into Two-Stream Multilayer Radiation Schemes

    E-print Network

    Hogan, Robin

    al. 2007). Numerous studies have high- lighted the radiative flux bias in climate models resulting and radiation in climate models is transport of radiation through cloud sides. In current climate modelsIncorporating the Effects of 3D Radiative Transfer in the Presence of Clouds into Two

  14. Use of multiincidence angle RADARSAT-1 SAR data to incorporate the effect of surface roughness in soil moisture estimation

    Microsoft Academic Search

    Hari Shanker Srivastava; Parul Patel; M. L. Manchanda; S. Adiga

    2003-01-01

    The proposed study offers an approach to incorporate the effect of surface roughness in the estimation of soil moisture from space without actually measuring surface roughness conditions on ground. It is required to acquire synthetic aperture radar data at low and high incidence angles, such that the soil moisture changes are negligible between the two acquisitions.

  15. Effect of nickel incorporation on the acidity and stability of HZSM-5 zeolite in the MTO process

    Microsoft Academic Search

    B. Valle; A. Alonso; A. Atutxa; A. G. Gayubo; J. Bilbao

    2005-01-01

    A study has been carried on the effect of Ni incorporation on the acidity (acid strength distribution and total acidity), on the hydrothermal stability of a HZSM-5 zeolite and on the kinetic performance of this catalyst in the MTO process at high temperature (up to 500°C, in order to increase selectivity to olefins) and when there is a high water

  16. Electrokinetic remediation of six emerging organic contaminants from soil.

    PubMed

    Guedes, Paula; Mateus, Eduardo P; Couto, Nazaré; Rodríguez, Yadira; Ribeiro, Alexandra B

    2014-12-01

    Some organic contaminants can accumulate in organisms and cause irreversible damages in biological systems through direct or indirect toxic effects. In this study the feasibility of the electrokinetic (EK) process for the remediation of 17?-oestradiol (E2), 17?-ethinyloestradiol (EE2), bisphenol A (BPA), nonylphenol (NP), octylphenol (OP) and triclosan (TCS) in soils was studied in a stationary laboratory cell. The experiments were conducted using a silty loam soil (S2) at 0, 10 and 20mA and a sandy soil (S3) at 0 and 10 mA. A pH control in the anolyte reservoir (pH>13) at 10 mA was carried out using S2, too. Photo and electrodegradation experiments were also fulfilled. Results showed that EK is a viable method for the remediation of these contaminants, both through mobilization by electroosmotic flow (EOF) and electrodegradation. As EOF is very sensible to soil pH, the control in the anolyte increased EOF rate, consequently enhancing contaminants mobilization towards the cathode end. The extent of the mobilization towards the electrode end was mainly dependent on compounds solubility and octanol-water partition coefficient. In the last 24h of experiments, BPA presented the highest mobilization rate (ca. 4 ?g min(-1)) with NP not being detected in the catholyte. At the end of all experiments the percentage of contaminants that remained in the soil ranged between 17 and 50 for S2, and between 27 and 48 for S3, with no statistical differences between treatments. The mass balance performed showed that the amount of contaminant not detected in the cell is similar to the quantity that potentially may suffer photo and electrodegradation. PMID:24997283

  17. Electrokinetic particle-electrode interactions at high frequencies.

    PubMed

    Yariv, Ehud; Schnitzer, Ory

    2013-01-01

    We provide a macroscale description of electrokinetic particle-electrode interactions at high frequencies, where chemical reactions at the electrodes are negligible. Using a thin-double-layer approximation, our starting point is the set of macroscale equations governing the "bounded" configuration comprising of a particle suspended between two electrodes, wherein the electrodes are governed by a capacitive charging condition and the imposed voltage is expressed as an integral constraint. In the large-cell limit the bounded model is transformed into an effectively equivalent "unbounded" model describing the interaction between the particle and a single electrode, where the imposed-voltage condition is manifested in a uniform field at infinity together with a Robin-type condition applying at the electrode. This condition, together with the standard no-flux condition applying at the particle surface, leads to a linear problem governing the electric potential in the fluid domain in which the dimensionless frequency ? of the applied voltage appears as a governing parameter. In the high-frequency limit ?>1 the flow is dominated by electro-osmotic slip at the particle surface, the contribution of electrode electro-osmosis being O(?(-2)) small. That simplification allows for a convenient analytical investigation of the prevailing case where the clearance between the particle and the adjacent electrode is small. Use of tangent-sphere coordinates allows to calculate the electric and flows fields as integral Hankel transforms. At large distances from the particle, along the electrode, both fields decay with the fourth power of distance. PMID:23410334

  18. Manure composition and incorporation effects on phosphorus in runoff following corn biomass removal.

    PubMed

    Yagüe, María R; Andraski, Todd W; Laboski, Carrie A M

    2011-01-01

    Greater demand for corn ( L.) stover for bioenergy use may lead to increased corn production acreage with minimal surface residue cover, resulting in greater risk for soil erosion and phosphorus (P) losses in runoff. A rainfall simulation study was conducted to determine the effects of spring-applied dairy cow () manure (none, in-barn composted, and exterior walled-enclosure pit) with >200 g kg organic solids content following fall corn biomass removal with and without incorporation (chisel plow [CP] and no-till [NT]) on sediment and P in runoff. Runoff was collected from a 0.83-m area for 60 min following the onset of rainfall simulation (76 mm h), once in spring and once in fall. Runoff dissolved reactive P (DRP) and dissolved organic P (DOP) concentrations were positively correlated with manure P rate and were higher in NT compared with CP. Conversely, sediment and particulate P (PP) concentrations in runoff were inversely correlated with manure P rate (and manure solids) and were higher in CP compared with NT. Runoff volume where no manure was applied was higher in NT than in CP in spring but similar in fall. The addition of manure reduced runoff volumes by an average of 82% in NT and 42% in CP over spring and fall. Results from this study indicate that surface application of dairy manure with relatively high solids content may reduce sediment and PP losses in runoff without increasing the risk of increased DRP and DOP losses in the year of application where corn biomass is harvested. PMID:22031580

  19. Effect of silicate modulus and metakaolin incorporation on the carbonation of alkali silicate-activated slags

    SciTech Connect

    Bernal, Susan A., E-mail: susana.bernal@gmail.co [Materials Engineering Department, Composite Materials Group, CENM, Universidad del Valle, Cali (Colombia); Mejia de Gutierrez, Ruby [Materials Engineering Department, Composite Materials Group, CENM, Universidad del Valle, Cali (Colombia); Provis, John L., E-mail: jprovis@unimelb.edu.a [Department of Chemical and Biomolecular Engineering, University of Melbourne, Victoria 3010 (Australia); Rose, Volker [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

    2010-06-15

    Accelerated carbonation is induced in pastes and mortars produced from alkali silicate-activated granulated blast furnace slag (GBFS)-metakaolin (MK) blends, by exposure to CO{sub 2}-rich gas atmospheres. Uncarbonated specimens show compressive strengths of up to 63 MPa after 28 days of curing when GBFS is used as the sole binder, and this decreases by 40-50% upon complete carbonation. The final strength of carbonated samples is largely independent of the extent of metakaolin incorporation up to 20%. Increasing the metakaolin content of the binder leads to a reduction in mechanical strength, more rapid carbonation, and an increase in capillary sorptivity. A higher susceptibility to carbonation is identified when activation is carried out with a lower solution modulus (SiO{sub 2}/Na{sub 2}O ratio) in metakaolin-free samples, but this trend is reversed when metakaolin is added due to the formation of secondary aluminosilicate phases. High-energy synchrotron X-ray diffractometry of uncarbonated paste samples shows that the main reaction products in alkali-activated GBFS/MK blends are C-S-H gels, and aluminosilicates with a zeolitic (gismondine) structure. The main crystalline carbonation products are calcite in all samples and trona only in samples containing no metakaolin, with carbonation taking place in the C-S-H gels of all samples, and involving the free Na{sup +} present in the pore solution of the metakaolin-free samples. Samples containing metakaolin do not appear to have the same availability of Na{sup +} for carbonation, indicating that this is more effectively bound in the presence of a secondary aluminosilicate gel phase. It is clear that claims of exceptional carbonation resistance in alkali-activated binders are not universally true, but by developing a fuller mechanistic understanding of this process, it will certainly be possible to improve performance in this area.

  20. Electrokinetic remediation. II. Amphoteric metals and enhancement with a weak acid

    SciTech Connect

    Wilson, D.J. [Vanderbilt Univ., Nashville, TN (United States); Rodriguez-Maroto, J.M.; Gomez-Lahoz, C. [Universidad de Malaga (Spain)

    1995-09-01

    A one-dimensional model is developed for the electrokinetic treatment of aquifers contaminated with an ionic salt. Electrokinetic removal of amphoteric metals such as zinc and lead is simulated. The use of a weak acid (acetic acid) to neutralize a portion of the OH{sup {minus}} generated electrolytically in the cathode compartment is explored in connection with the electrokinetic removal of nonamphoteric metals such as copper and cadmium.

  1. On-chip Micro- and Nanofluidic Electrokinetic Injection and Separation for PEGylation Analysis

    NASA Astrophysics Data System (ADS)

    Shelton, Elijah; Baum, Mary; Morse, Dan; Pennathur, Sumita; Pennathur Nanofluidics Laboratory Collaboration; Morse Laboratory Collaboration

    2012-11-01

    We present an experimental study of micro- and nanofluidic electrokinetic injection and separation in borosilcate channels as a method for characterizing size and zeta potential of biomolecules-specifically polyethlylene glycol (PEG), keyhole limpet hemocyanine (KLH), and pegylated KLH. While pegylation (the conjugation of proteins with PEG) is an established technique for enhancing a protein's therapeutic properties, reliable characterization of these conjugations by traditional analysis techniques (i.e. gel-electrophoresis, zetasizer) remains a challenge. Using a three-step electrokinetic sequence (load, gate, and inject), FITC labeled species and a fluorescein tracer dye are injected into a channel where they separate according to differences in electrophoretic mobility. We find the average absolute mobility of pegylated subunit KLH in 1 micron channels to be 56% that of unpegylated subunit KLH. In a 250 nm channel, we measure a 33% shift in the average absolute mobility of PEG dendrimers as compared to measurements in a 1 micron channel. These results begin to demonstrate how a micro- and nanofluidic-based approach might address the demand for effective and accessible nanoparticle characterization platforms. Supported by the Institute for Collaborative Biotechnologies.

  2. Rapid antimicrobial susceptibility testing with electrokinetics enhanced biosensors for diagnosis of acute bacterial infections.

    PubMed

    Liu, Tingting; Lu, Yi; Gau, Vincent; Liao, Joseph C; Wong, Pak Kin

    2014-11-01

    Rapid pathogen detection and antimicrobial susceptibility testing (AST) are required in diagnosis of acute bacterial infections to determine the appropriate antibiotic treatment. Molecular approaches for AST are often based on the detection of known antibiotic resistance genes. Phenotypic culture analysis requires several days from sample collection to result reporting. Toward rapid diagnosis of bacterial infection in non-traditional healthcare settings, we have developed a rapid AST approach that combines phenotypic culture of bacterial pathogens in physiological samples and electrochemical sensing of bacterial 16S rRNA. The assay determines the susceptibility of pathogens by detecting bacterial growth under various antibiotic conditions. AC electrokinetic fluid motion and Joule heating induced temperature elevation are optimized to enhance the sensor signal and minimize the matrix effect, which improve the overall sensitivity of the assay. The electrokinetics enhanced biosensor directly detects the bacterial pathogens in blood culture without prior purification. Rapid determination of the antibiotic resistance profile of Escherichia coli clinical isolates is demonstrated. PMID:24889716

  3. Capillary electrokinetic separations with optical detection. Technical progress report, February 1, 1993--January 31, 1994

    SciTech Connect

    Sepaniak, M.J.

    1993-10-01

    This program seeks the development of capillary electrokinetic separation techniques and associated optical methods of detection. Fundamental studies of pertinent separation and band broadening mechanisms are being conducted, with the emphasis on understanding systems that include highly-ordered assemblies as running buffer additives. The additives include cyclodextrins, affinity reagents, and soluble (entangled) polymers and are employed with capillary electrophoresis, CE and/or micellar electrokinetic capillary chromatography, MECC modes of separation. The utility of molecular modeling techniques for predicting the effects of highly ordered assemblies on the retention behavior of isomeric compounds is under investigation. The feasibility of performing separations using a non-aqueous solvent/fullerene electrochromatographic system is being explored. The analytical methodologies associated with these capillary separation techniques are being advanced through the development of retention programming instumentation/techniques and new strategies for performing optical detection. The advantages of laser fluorimetry are extended through the inclusion of fluorogenic, reagents in the running buffer. These reagents include oligonucleotide intercalation reagents for detecting DNA fragments. Chemiluminescence detection using post-capillary reactors/flow cells is also in progress. Successful development of these separation and detection systems will fill current voids in the capabilities of capillary separation techniques.

  4. Behavior of thin-walled beams made of advanced composite materials and incorporating non-classical effects

    Microsoft Academic Search

    Liviu Librescu; Ohseop Song

    1991-01-01

    Several results concerning the refined theory of thin-walled beams of arbitrary closed cross-section incorporating nonclassical effects are presented. These effects are related both with the exotic properties characterizing the advanced composite material structures and the nonuniform torsional model. A special case of the general equations is used to study several problems of cantilevered thin-walled beams and to assess the influence

  5. The Perceived Effect of the Sociocultural Context on HIV/AIDS Identity Incorporation

    ERIC Educational Resources Information Center

    Baumgartner, Lisa M.

    2012-01-01

    Contexts influence the experience of disease. In this study, I examined how the sociocultural context (e.g., race, class, gender, and sexual orientation) affected the experience of living with HIV/AIDS and the incorporation of the HIV/AIDS identity into the self. I interviewed 36 individuals living with HIV/AIDS. Findings indicate that race,…

  6. The Perceived Effect of Time on HIV/AIDS Identity Incorporation

    ERIC Educational Resources Information Center

    Baumgartner, Lisa M.

    2012-01-01

    Individuals experience disease in a variety of contexts. In this study, I examined how the temporal context (e.g., historical time, social time, chronological age and the passage of time) affected the incorporation of the HIV/AIDS identity into the self. I used semi structured interviews to collect data from 36 individuals living with HIV/AIDS.…

  7. Effects of oxygen incorporation in GeSbTe films on electrical properties and thermal stability

    SciTech Connect

    Jang, Moon Hyung; Park, Seung Jong; Lim, Dong Hyeok; Park, Sung Jin; Cho, Mann-Ho [Institute of Physics and Applied Physics, Yonsei University, Seoul 120-749 (Korea, Republic of); Cho, Seong Jin [Department of Physics, Kyungseong University, Pusan 608-736 (Korea, Republic of); Cho, Yoon Ho; Lee, Jong-Heun [Division of Materials Science and Engineering, Korea University, Seoul 136-701 (Korea, Republic of)

    2010-03-01

    Oxygen incorporated Ge{sub 2}Sb{sub 2}Te{sub 5} (GST) films were prepared by an ion beam sputtering deposition method. I-V curves of the oxygen incorporated GST active layer showed that the threshold voltage (V{sub th}) varied, depending on the level of incorporated oxygen. In the case of a GST film with an elevated oxygen content of 30.8%, the GST layer melted at 9.02 V due to the instability conferred by the high oxygen content. The formation of Ge-deficient hexagonal phases such as GeSb{sub 2}Te{sub 4} and Sb{sub 2}Te{sub 3} appear to be responsible for the V{sub th} variation. Impedance analyses indicated that the resistance in GST films with oxygen contents of 16.7% and 21.7% had different origins. Thermal desorption spectroscopy data indicate that moisture and hydrocarbons were more readily desorbed at higher oxygen content because the oxygen incorporated GST films are more hydrophilic than undoped GST films.

  8. Effect of incorporation of distillers' dried grain with solubles (DDGS) on quality of cornbread

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Recent increase in biofuel production creates a sizable stockpile of its co-product in the form of Distiller’s Dried Grain with Solubles (DDGS) that needs to be utilized beyond animal feeds. We evaluated cornbreads, which were formulated incorporating 0, 5, 10, 15, 20, 25, and 30% corn DDGS into co...

  9. Saline or plant-incorporated methylmercury effects on distribution, demethylation, and blood parameters in rats

    Microsoft Academic Search

    M. Czuba; E. Komsta-Szumska; D. C. Mortimer; C. Champagne

    1987-01-01

    The influence of diet is recognized as a significant factor in the expression of toxicity. This applies particularly to toxins like methylmercury (MeHg) which are metabolically incorporated into growing food plants and biotransformed within the plant before ingestion. Methylmercury in this form may influence the early physiological and biochemical events which lead to development of toxicity. In a previous study,

  10. EFFECTS OF ROCK FRAGMENTS INCORPORATED IN THE SOIL MATRIX ON CONCENTRATED FLOW HYDRAULICS AND EROSION 1836

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rock fragments can act as a controlling factor for erosional rates and patterns in the landscape. Thus, the objective of this study is to better understand the role that rock fragments incorporated into the soil matrix have on concentrated flow hydraulics and erosion . Laboratory flume experiments...

  11. WATER-QUALITY EFFECTS OF INCORPORATING POULTRY LITTER INTO PERENNIAL GRASSLAND SOILS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Poultry litter provides a rich source of nutrients for perennial forages, but the usual practice of surface-applying litter to pastures can degrade water quality by allowing nutrients to be transported from fields in surface runoff, while much of the NH4-N volatilizes. Incorporating litter into the...

  12. Incorporating the effects of habitat edges into landscape models: Effective area models for cross-boundary management.

    SciTech Connect

    T.D. Sisk; N.M. Haddad

    2002-01-01

    Sisk, T.D., and N.M. Haddad. 2002. Incorporating the effects of habitat edges into landscape models: Effective area models for cross-boundary management. Chapter 8, Pp. 208-240 in J. Liu and W.W. Taylor, Integrating landscape ecology into natural resource management, Cambridge University Press, Cambridge, UK. Abstract: Natural resource managers are increasingly charged with meeting multiple, often conflicting goals in landscapes undergoing significant change due to shifts in land use. Conservation from native to anthropogenic habitats typically fragments the landscape, reducing the size and increasing the isolation of the resulting patches, with profound ecological impacts. These impacts occur both within and adjacent to areas under active management, creating extensive edges between habitat types. Boundaries established between management areas, for example, between timber harvest units or between reserves and adjacent agricultural fields, inevitably lead to differences in the quality of habitats on either side of the boundary, and a habitat edge results. Although edges are common components of undisturbed landscapes, the amount of edge proliferates rapidly as landscapes are fragmented. Insightful analysis of the complex issues associated with cross-boundary management necessitates an explicit focus on habitat quality in the boundary regions.

  13. Hydrodynamics and electrokinetics of spherical liposomes with coatings of terminally anchored poly(ethylene glycol): numerically exact electrokinetics with self-consistent mean-field polymer.

    PubMed

    Hill, Reghan J

    2004-11-01

    A detailed theoretical model is presented to interpret electrokinetic experiments performed on colloids with uncharged polymer layers. The methodology removes many of the degrees of freedom that otherwise have to be accounted for by adopting multiple empirical fitting parameters. Furthermore, the level of detail provides a firm basis for future studies examining liposome surface chemistry and charge, surface-charge mobility, and the dynamics of adsorbed polymer on fluidlike membranes. The model predictions are compared with experimental measurements of the electrophoretic mobility of stealth liposomes with molecular weights of terminally anchored poly(ethylene glycol) (PEG) in the range 0.35-10 kg mol(-1) [J.A. Cohen and V.A. Khorosheva, Colloids Surf. A 195, 113 (2001)]. The experimental data are interpreted by drawing upon self-consistent mean-field calculations of the polymer segment density distributions and numerically exact solutions of the governing transport equations [R.J. Hill, D.A. Saville, and W.B. Russel, J. Colloid Interface Sci. 258, 56 (2003)]. The approach leads to excellent agreement between theory and experiment with one adjustable parameter--the hydrodynamic size (Stokes radius) a(s) approximately equal to 0.175 A of the statistical PEG segments with (Kuhn) length l=7.1 A . The remarkably small Stokes radius is demonstrated to be consistent with other applications of the well-known Debye-Brinkman model and, consequently, this work reveals important limitations of the mean-field hydrodynamic model. Despite such limitations, the "full" electrokinetic model is robust in its predictive capacity. The molecular weights of the terminally anchored PEG span the range where the coatings undergo a transition from mushroomlike to brushlike conformations, and the hydrodynamic size and electrophoretic mobility of the liposomes are demonstrated to be sensitive to the PEG chain length and the effects of double-layer polarization. PMID:15600617

  14. Hydrodynamics and electrokinetics of spherical liposomes with coatings of terminally anchored poly(ethylene glycol): Numerically exact electrokinetics with self-consistent mean-field polymer

    NASA Astrophysics Data System (ADS)

    Hill, Reghan J.

    2004-11-01

    A detailed theoretical model is presented to interpret electrokinetic experiments performed on colloids with uncharged polymer layers. The methodology removes many of the degrees of freedom that otherwise have to be accounted for by adopting multiple empirical fitting parameters. Furthermore, the level of detail provides a firm basis for future studies examining liposome surface chemistry and charge, surface-charge mobility, and the dynamics of adsorbed polymer on fluidlike membranes. The model predictions are compared with experimental measurements of the electrophoretic mobility of stealth liposomes with molecular weights of terminally anchored poly(ethylene glycol) (PEG) in the range 0.35-10kgmol-1 [J. A. Cohen and V. A. Khorosheva, Colloids Surf. A 195, 113 (2001)]. The experimental data are interpreted by drawing upon self-consistent mean-field calculations of the polymer segment density distributions and numerically exact solutions of the governing transport equations [R. J. Hill, D. A. Saville, and W. B. Russel, J. Colloid Interface Sci. 258, 56 (2003)]. The approach leads to excellent agreement between theory and experiment with one adjustable parameter—the hydrodynamic size (Stokes radius) as?0.175Å of the statistical PEG segments with (Kuhn) length l=7.1Å . The remarkably small Stokes radius is demonstrated to be consistent with other applications of the well-known Debye-Brinkman model and, consequently, this work reveals important limitations of the mean-field hydrodynamic model. Despite such limitations, the “full” electrokinetic model is robust in its predictive capacity. The molecular weights of the terminally anchored PEG span the range where the coatings undergo a transition from mushroomlike to brushlike conformations, and the hydrodynamic size and electrophoretic mobility of the liposomes are demonstrated to be sensitive to the PEG chain length and the effects of double-layer polarization.

  15. Electrokinetic Concentration of Charged Macromolecules In Nanoporous Media

    NASA Astrophysics Data System (ADS)

    Kirby, Brian J.; Throckmorton, Daniel J.

    2005-03-01

    We present a technique for concentrating proteins and other charged macromolecules in microfabricated systems through the manipulation of molecular electromigration at the interface between bulk flow in microchannels and flow through micro/nanoporous material with a bimodal pore distribution. The presence of a bimodal pore structure allows for the creation of metastable electrokinetic regions in areas of double layer overlap without the attendant electrokinetic pressure generation required for continuity in transitions between open microchannels and unimodal nanoporous structures. Directed experiments on the dependence of the observed phenomena on pH, macromolecule charge state, chemi- and electrosorption are supportive of a relatively simple model that defines the criteria that must be satisfied to observe macromolecule concentration. This technique has been applied to concentrate proteins by 2-3 orders of magnitude before pressure elution for analysis, and has been implemented with both polymeric and silicate materials in capillaries and in microfabricated glass microfluidic devices.

  16. Testing and evaluation of electrokinetic decontamination of concrete

    SciTech Connect

    DePaoli, D.W.; Harris, M.T.; Ally, M.R. [Oak Ridge National Lab., TN (United States). Chemical Technology Div.] [and others

    1996-10-01

    The goals and objectives of the technical task plan (TTP) are to (1) describe the nature and extent of concrete contamination within the Department of Energy (DOE) complex and emerging and commercial technologies applicable to these problems; (2) to match technologies to the concrete problems and recommend up to four demonstrations; (3) to initiate recommended demonstrations; and (4) to continue investigation and evaluation of the application of electrokinetic decontamination processes to concrete. This document presents findings of experimental and theoretical studies of the electrokinetic decontamination (EK) process and their implications for field demonstrations. This effort is an extension of the work performed under TTP 142005, ``Electroosmotic Concrete Decontamination. The goals of this task were to determine the applicability of EK for treating contaminated concrete and, if warranted, to evaluate EK as a potential technology for demonstration. 62 refs.

  17. Electrokinetic settling and sedimentation behavior of cohesive soils in dilute suspension.

    PubMed

    Kim, Soo Sam; Lee, Myungho; Kim, Dae-Ho

    2008-07-01

    In this study, the electrokinetic (EK) effects on settling behavior of clayey soils under different electrolyte solution, electric field strength, and moisture content were evaluated using kaolin and natural marine clay. A number of laboratory-scale column experiment were carried out in order to examine the effects of electrophoresis and electro-osmosis during settling processes. The settling velocity under different electrolyte solution was found to become faster resulting from the formation of floc due to the contraction of electrical double layer. The electrically induced surface settlement was faster in settling rate and greater in magnitude by comparison with that under the conventional gravitational sedimentation. The effects of electrophoresis on settling behavior become significant from the beginning of hindered settling stage due to the influence of electrochemical interactions between the charged clay particles. PMID:18569311

  18. Micellar electrokinetic chromatography of scopolamine-related anticholinergics

    Microsoft Academic Search

    Hsin-Lung Wu; Chiu-Hui Huang; Su-Hwei Chen; Shou-Mei Wu

    1998-01-01

    A simple micellar electrokinetic chromatography (MEKC) method is described for the separation of scopolamine N-oxide hydrobromide (SO), scopolamine hydrobromide (SH), scopolamine N-methylbromide (SM) and scopolamine N-butylbromide (SB), and for the quantitation of SH, SM and SB (using SO as an internal standard). The analysis of these drugs was performed in a phosphate buffer (30 mM; pH 7.00) with sodium dodecyl

  19. Analysis of post-harvest fungicides by micellar electrokinetic chromatography

    Microsoft Academic Search

    R. Rodr??guez; Y. Picó; J. Mañes

    2001-01-01

    A method based on solid-phase extraction (SPE) and micellar electrokinetic chromatography (MEKC) was developed for the simultaneous determination of carbendazim, imazalil, methylthiophanate, O-phenylphenol, prochloraz, procimidone, thiabendazole and triadimefon residues in grape, lettuce, orange and tomato. Selectivity and resolution were studied changing the pH and the concentration of the buffer, the type and concentration of surfactant and the methanol content in

  20. Electrokinetically Pumped Liquid Propellant Microthrusters for Orbital Station Keeping

    Microsoft Academic Search

    Michael S. Bartsch; M. H. McCrink; R. W. Crocker; B. P. Mosier; K. A. Peterson; K. Wally; K. D. Patel

    2007-01-01

    For most orbital maneuvers, small satellites in the sub-10 kg range require thrusters capable of spanning the micro-Newton to milli-Newton force range. At this scale, electrokinetic (EK) pumping offers precise metering of monergolic or hypergolic liquid propellants under purely electrical control at pressures and flow rates well-suited to microthruster applications. We have demonstrated direct and indirect EK pumping for delivery

  1. Phytolith assaying using a micron-scale electrokinetic sorting ring

    Microsoft Academic Search

    Kevin G. Stanley; Elizabeth Cornelia Robertson; Rene d’Entremont; Ted Hubbard; Marek Kujath

    A particularly useful indicator of past vegetation are phytoliths, glassy products of plant metabolism which have distinctive\\u000a size and morphology based on the plant taxa which produced them; however, their analysis is a time-consuming task. Building\\u000a on investigations into mobilizing and sorting of synthetic polystyrene microspheres using a closed loop rectangular microelectromechanical\\u000a systems (MEMS) electrokinetic array, we investigate these devices’

  2. Separation of hydrophobic polymer additives by microemulsion electrokinetic chromatography

    Microsoft Academic Search

    Emily F Hilder; Christian W Klampfl; Wolfgang Buchberger; Paul R Haddad

    2001-01-01

    Microemulsion electrokinetic chromatography (MEEKC) has been applied to the separation of some phenolic anti-oxidants [Irganox 1024, Irganox 1035, Irganox 1076, Irganox 1010, Irganox 1330, Irgafos 138, Irganox 168 and 2,6-di-tert.-butyl-4-methylphenol (BHT)]. Due to the extremely hydrophobic nature of these analytes, they could not be separated using standard MEEKC conditions and two alternative approaches were investigated. Using an acidic buffer (phosphate,

  3. Incorporating Multi-Nucleon Effects in T2K's Neutrino Interaction Simulation Software.

    NASA Astrophysics Data System (ADS)

    Schwehr, Jaclyn

    2013-04-01

    The interaction of neutrinos with heavy nuclei is a field of study that has grown rapidly as more experiments are built with heavier targets. Neutrinos interacting with these targets are thought to interact with not just single nucleons, but also with correlated groups of nucleons. A number of different theories exist that describe these multi-nucleon interactions, but to be able to compare these theories with one another or to data requires a way to work them into the neutrino interaction simulation software. The T2K experiment uses NEUT (the neutrino interaction simulation program at Super-K) in the study of neutrino cross sections. In the interest of simulating neutrino interactions more accurately, new interaction models need to be incorporated into this simulation package. This talk will discuss the discrepancies between measurements done with neutrinos interacting on light verses heavy nuclei, a few of the models describing these discrepancies, and finally how these models are being incorporated into NEUT.?

  4. Effect of nickel incorporation on the optical properties of diamond-like carbon (DLC) matrix

    NASA Astrophysics Data System (ADS)

    Pandey, B.; Hussain, S.

    2011-10-01

    The present study investigates the optical behavior of composite nanostructured DLC based films and functional coatings. Diamond-like carbon (DLC) thin films were synthesized by electrodeposition method onto SnO 2 -coated glass substrates using an electrolyte of a mixture of acetic acid and water. Nanoparticles of nickel were then introduced into the DLC matrix. Morphology of the metal incorporated thin films and distribution of nanoparticles were studied by SEM; continuous homogeneous distribution of the particles was observed. Raman spectroscopy showed additional peaks in addition to the peaks due to DLC matrix. FTIR spectra revealed new peaks in the lower wave number region due to metal inclusion. UV-vis transmittance studies were performed to calculate the band gap of the samples. The estimated band gap from the Tauc relation was found to vary from 2.63 eV for the virgin DLC to 1.48 eV for the metal incorporated DLC.

  5. Effect of Tin Incorporation on Thermo-Mechanical Properties of Glassy Se80Te20 Alloy

    NASA Astrophysics Data System (ADS)

    H., Kumar; Sharma, A.; N., Mehta

    2014-03-01

    We report an analysis on the hardness behavior of glassy Se80-xTe20Snx alloy. The crucial thermo-mechanical parameters (micro-hardness, volume and formation energy of micro-voids and the modulus of elasticity) are examined. The results indicate that the thermo-mechanical parameters are changed significantly after incorporation of Sn in glassy Se80Te20 alloy.

  6. Saline or plant-incorporated methylmercury effects on distribution, demethylation, and blood parameters in rats

    SciTech Connect

    Czuba, M.; Komsta-Szumska, E.; Mortimer, D.C.; Champagne, C.

    1987-03-01

    The influence of diet is recognized as a significant factor in the expression of toxicity. This applies particularly to toxins like methylmercury (MeHg) which are metabolically incorporated into growing food plants and biotransformed within the plant before ingestion. Methylmercury in this form may influence the early physiological and biochemical events which lead to development of toxicity. In a previous study, a single dose of plant-incorporated methylmercury (MeHg) had a different route of distribution and accumulation in rat organs after 48 h than an equivalent dose of saline MeHg with the greatest accumulation being in red blood cells. Creatine, an important storage form of high energy phosphate in muscles is a primary indicator of erythropoietic dynamics under hypoxia, a sensitive indicator of hemolytic disease, red blood cell aging and impaired marrow efficiency. Since changes in creatine levels occur sooner than changes in other blood parameters, itself being neither synthesized nor metabolized by red blood cells, it can be used as a sensitive indicator of toxicity. The present work investigates the difference in a longer term, multiple-dose regime of saline or bean-incorporated MeHg ingestion with special attention being given to various blood parameters.

  7. Principles of micellar electrokinetic capillary chromatography applied in pharmaceutical analysis.

    PubMed

    Hancu, Gabriel; Simon, Brigitta; Rusu, Aura; Mircia, Eleonora; Gyéresi, Arpád

    2013-01-01

    Since its introduction capillary electrophoresis has shown great potential in areas where electrophoretic techniques have rarely been used before, including here the analysis of pharmaceutical substances. The large majority of pharmaceutical substances are neutral from electrophoretic point of view, consequently separations by the classic capillary zone electrophoresis; where separation is based on the differences between the own electrophoretic mobilities of the analytes; are hard to achieve. Micellar electrokinetic capillary chromatography, a hybrid method that combines chromatographic and electrophoretic separation principles, extends the applicability of capillary electrophoretic methods to neutral analytes. In micellar electrokinetic capillary chromatography, surfactants are added to the buffer solution in concentration above their critical micellar concentrations, consequently micelles are formed; micelles that undergo electrophoretic migration like any other charged particle. The separation is based on the differential partitioning of an analyte between the two-phase system: the mobile aqueous phase and micellar pseudostationary phase. The present paper aims to summarize the basic aspects regarding separation principles and practical applications of micellar electrokinetic capillary chromatography, with particular attention to those relevant in pharmaceutical analysis. PMID:24312804

  8. Principles of Micellar Electrokinetic Capillary Chromatography Applied in Pharmaceutical Analysis

    PubMed Central

    Hancu, Gabriel; Simon, Brigitta; Rusu, Aura; Mircia, Eleonora; Gyéresi, Árpád

    2013-01-01

    Since its introduction capillary electrophoresis has shown great potential in areas where electrophoretic techniques have rarely been used before, including here the analysis of pharmaceutical substances. The large majority of pharmaceutical substances are neutral from electrophoretic point of view, consequently separations by the classic capillary zone electrophoresis; where separation is based on the differences between the own electrophoretic mobilities of the analytes; are hard to achieve. Micellar electrokinetic capillary chromatography, a hybrid method that combines chromatographic and electrophoretic separation principles, extends the applicability of capillary electrophoretic methods to neutral analytes. In micellar electrokinetic capillary chromatography, surfactants are added to the buffer solution in concentration above their critical micellar concentrations, consequently micelles are formed; micelles that undergo electrophoretic migration like any other charged particle. The separation is based on the differential partitioning of an analyte between the two-phase system: the mobile aqueous phase and micellar pseudostationary phase. The present paper aims to summarize the basic aspects regarding separation principles and practical applications of micellar electrokinetic capillary chromatography, with particular attention to those relevant in pharmaceutical analysis. PMID:24312804

  9. Effect of Incorporation of Various Food By-products on Some Nutritional Properties of Rice-based Extruded Foods

    Microsoft Academic Search

    S. Ya?c?; F. Gö?ü?

    2009-01-01

    Various food by-products were incorporated into rice grits and submitted to extrusion cooking to produce fortified extruded food products. The blends of various formulations of durum clear flour (8—20%), partially defatted hazelnut flour (PDHF) (5—15%), fruit waste blend (3—7%) and rice grits were extruded using single screw extruder. Response surface methodology was used to evaluate the effects of process variables,

  10. [Effect of salvin on the incorporation of labeled precursors into macromolecular compounds of Staphylococcus aureus 209P].

    PubMed

    Pavlenko, L V; Mashkovski?, N N; Smirnov, V V

    1989-08-01

    Salvin is a preparation of Salvia officinalis L. Its effect on synthesis of macromolecules in cells of Staphylococcus aureus 209P was studied with labeled precursors in a system used for investigation of peptidoglycan synthesis. At a concentration of 10 micrograms/ml salvin inhibited incorporation of 14C-lysine into the cell wall polymer and protein fraction by 42.9 and 8.9 per cent respectively and stimulated incorporation of 3H-thymidine and 3H-uridine into the nucleic acid fraction. In the presence of salvin in a quantity of 120 micrograms/ml there was observed inhibition of 3H-uridine incorporation into the nucleic acid fraction by 53.3 per cent and 14C-lysine into the protein fraction by 74.5 per cent along with inhibition of peptidoglycan synthesis by 95.5 per cent. The results conformed to the findings of electron microscopic investigation of the solving effect on ultrastructure of S. aureus 209P. They confirmed the previous assumption that salvin had the primary effect on the processes directly associated with synthesis of the cell wall polymer. PMID:2480082

  11. Electrokinetic transport of diesel-degrading microorganisms through soils of different textures using electric fields

    Microsoft Academic Search

    Esperanza Mena; Patricia Rubio; Pablo Cañizares; José Villaseñor; Manuel A. Rodrigo

    2012-01-01

    The mobilisation of diesel-degrading microorganisms in soils of three different textures (sandy, clay and silty) using electrokinetic techniques was studied. The mobilisation tests were performed using a laboratory-scale electrokinetic cell in which a synthetic soil column was inserted between the cathode and anode compartments. Microorganisms were located at the anode compartment at the beginning of each assay. A constant cell

  12. Stability and electrokinetic potential of silicon carbide suspensions in aqueous organic media

    NASA Technical Reports Server (NTRS)

    Yeremenko, B. V.; Lyubchenko, I. N.; Skobets, I. Y.

    1984-01-01

    The method of electroosmosis was used to study the dependence of the electrokinetic potential of silicon carbide suspensions in mixtures of water -n. alcohol. The reasons for the dependence of the electrokinetic potential on the composition of the intermicellar liquid are discussed.

  13. A soft-lithographed chaotic electrokinetic micromixer for efficient chemical reactions in lab-on-chips

    E-print Network

    M. Campisi; D. Accoto; F. Damiani; P. Dario

    2007-05-08

    Mixing is one of the basic functions which automated lab-on-chips require for the effective management of liquid samples. In this paper we report on the working principle, design, fabrication and experimental characterization of a soft-lithographed micromixer for microfluidic applications. The device effectively mixes two liquids by means of chaotic advection obtained as an implementation of a Linked Twisted Map (LTM). In this sense it is chaotic. The liquids are electrokinetically displaced by generating rolls through AC electroosmosis on co-planar electrodes. The device performance has been tested on dyed DI-water for several voltages, frequencies and flow-rates, displaying good mixing properties in the range of $10 \\div 100$kHz, at low peak-to-peak voltages ($\\sim15 \\div 20$ volts). Low voltage supply, small dimensions and possibility of fabrication via standard lithographic techniques make the device highly integrable in lab-on-a-chip platforms.

  14. Quantitative Determination of Lattice Fluoride Effects on the Solubility and Crystallinity of Carbonated Apatites with Incorporated Fluoride

    PubMed Central

    Yan, Guang; Moribe, Kunikazu; Otsuka, Makoto; Papangkorn, Kongnara; Higuchi, William I.

    2013-01-01

    The purpose of this study was to evaluate quantitatively the effects of fluoride on the solubility and crystallinity of carbonated apatites (CAPs) after its incorporation into the crystal lattice using the metastable equilibrium solubility (MES) distribution method. Fluoride incorporated CAPs (F-CAPs) of two different carbonate levels (3% and 5%) and fluoride contents from 0 to 20,000 ?g/g were synthesized. X-ray diffraction experiments and Rietveld analysis were conducted to obtain crystallite microstrain and unit cell parameters. Acetate buffer MES solution media were prepared at two solution fluoride concentrations (0.2 mg/L and 2.0 mg/L) and at two pHs (5.0 and 5.7). The unit cell a-axis values of the F-CAPs were found to decrease as the fluoride content increased; consistent with the fluoride being incorporated into the crystal lattice. The fluoride concentrations in the MES solution media were high enough to provide a “swamping” effect such that the fluoride released from the F-CAPs during dissolution was minimal in changing the solution fluoride concentration. Employing the MES distribution superposition method, it was shown that the surface complex possessing the fluorapatite (FAP) stoichiometry (Ca10(PO4)6F2) accounted for the MES distribution behavior of all experiments. In addition, the mean pIFAP [the value of ?log(aca 10PO46aF2) calculated from ionic activity product based on FAP stoichiometry of the MES dissolution media in which 50% of the F-CAP had dissolved] correlated well with the crystallite microstrain parameters of the F-CAPs. The incorporated fluoride in the F-CAPs showed only modest effects on F-CAP crystallinity and solubility. PMID:23235353

  15. Effect of Length of Time before Incorporation on Survival of Pathogenic Bacteria Present in Livestock Wastes Applied to Agricultural Soil

    PubMed Central

    Hutchison, M. L.; Walters, L. D.; Moore, A.; Crookes, K. M.; Avery, S. M.

    2004-01-01

    In response to reports that the contamination of food can occur during the on-farm primary phase of food production, we report data that describes a possible cost-effective intervention measure. The effect of time before soil incorporation of livestock wastes spread to land on the rate of decline of zoonotic agents present in the waste was investigated. Fresh livestock wastes were inoculated with laboratory-cultured Salmonella, Listeria, and Campylobacter spp. and Escherichia coli O157 before they were spead onto soil. Incorporation of the spread wastes was either immediate, delayed for 1 week, or did not occur at all. Bacterial decline was monitored over time and found to be significantly more rapid for all waste types when they were left on the soil surface. There were no significant differences in initial bacterial decline rates when wastes were spread in summer or winter. Our results indicate that not incorporating contaminated livestock wastes into soil is a potential intervention measure that may help to limit the spread of zoonotic agents further up the food chain. The implications of these findings are discussed in relation to current advice for livestock waste disposal. PMID:15345389

  16. Design and development of an effective optical-variable-device-based security system incorporating additional synergistic security technologies

    NASA Astrophysics Data System (ADS)

    Wolpert, Gary R.

    2000-04-01

    Optically variable devices (OVDs) are becoming ever more popular as tools to provide security for documents and products subject to counterfeiting, forgery, and/or diversion. Issues faced during the design and implementation of OVDs for a specific security application include matching the proper security feature for its intended function, determining the method of the security features authenticity, and incorporating effective anti- counterfeiting protection for the OVD itself. Combining additional synergistic security technologies can be an effective approach to meeting the desired objectives in designing and implementing a security feature.

  17. On-line micellar electrokinetic chromatography-electrospray ionization mass spectrometry using anodically migrating micelles

    SciTech Connect

    Yang, L.; Harrata, A.K.; Lee, C.S. [Ames Lab., IA (United States)] [Ames Lab., IA (United States); [Iowa State Univ., Ames, IA (United States)

    1997-05-15

    On-line micellar electrokinetic chromatography (MEKC)-electrospray ionization mass spectrometry (ESIMS) is demonstrated for the analysis of chlorotriazine herbicides and barbiturates. In this study, the micellar velocity is directly manipulated by the adjustment of electroosmosis rather than the electrophoretic velocity of the micelle. The electroosmotic flow is adjusted against the electrophoretic velocity of the micelle by changing the solution pH in MEKC. The elimination of MEKC surfactant introduction into ESIMS is achieved with an anodically migrating micelle, moving away from the electrospray interface. The effects of moving surfactant boundary in the MEKC capillary on separation efficiency and resolution of triazine herbicides and barbiturates are investigated. The mass detection of herbicides and barbiturates sequentially eluted from the MEKC capillary is acquired using the positive and negative electrospray modes, respectively. 30 refs., 8 figs., 3 tabs.

  18. Continuous Signal Enhancement for Sensitive Aptamer Affinity Probe Electrophoresis Assay Using Electrokinetic Concentration

    PubMed Central

    Cheow, Lih Feng; Han, Jongyoon

    2011-01-01

    We describe an electrokinetic concentration-enhanced aptamer affinity probe electrophoresis assay to achieve highly sensitive and quantitative detection of protein targets in a microfluidic device. The key weaknesses of aptamer as a binding agent (weak binding strength/fast target dissociation) were counteracted by continuous injection of fresh sample while band-broadening phenomena were minimized due to self-focusing effects. With 30 minutes of continuous signal enhancement, we can detect 4.4 pM of human immunoglobulin E (IgE) and 9 pM of human immunodifficiency virus 1 reverse transcriptase (HIV-1 RT), which is among the lowest limit of detection (LOD) reported. IgE was detected in serum sample with LOD of 39 pM due to nonspecific interactions between aptamers and serum proteins. The method presented in this paper also has broad applicability to improve sensitivities of various other mobility shift assays. PMID:21809885

  19. Polyphenolic extracts of edible flowers incorporated onto atelocollagen matrices and their effect on cell viability.

    PubMed

    López-García, Jorge; Kuceková, Zdenka; Humpolí?ek, Petr; Ml?ek, Ji?i; Sáha, Petr

    2013-01-01

    The phenolic extract of chives flowers (Allium schoenoprasum, Liliaceae), introduced Sage (Salvia pratensis, Lamiaceae), European elderberry (Sambucus nigra, Caprifoliaceae) and common dandelion (Taraxacum officinale, Asteraceae) were characterised by High Performance Liquid Chromatography and incorporated in different concentrations onto atelocollagen thin films. In order to assess the biological impact of these phenolic compounds on cell viability, human immortalised non-tumorigenic keratinocyte cell line was seeded on the thin films and cell proliferation was determined by using an MTT assay. In addition, their antimicrobial activity was estimated by using an agar diffusion test. Data indicated the concomitance between cell viability and concentration of polyphenols. These findings suggest that these phenolic-endowed atelocollagen films might be suitable for tissue engineering applications, on account of the combined activity of polyphenols and collagen. PMID:24177700

  20. Prioritizing urban sustainability solutions: coordinated approaches must incorporate scale-dependent built environment induced effects

    NASA Astrophysics Data System (ADS)

    Georgescu, M.; Chow, W. T. L.; Wang, Z. H.; Brazel, A.; Trapido-Lurie, B.; Roth, M.; Benson-Lira, V.

    2015-06-01

    Because of a projected surge of several billion urban inhabitants by mid-century, a rising urgency exists to advance local and strategically deployed measures intended to ameliorate negative consequences on urban climate (e.g., heat stress, poor air quality, energy/water availability). Here we highlight the importance of incorporating scale-dependent built environment induced solutions within the broader umbrella of urban sustainability outcomes, thereby accounting for fundamental physical principles. Contemporary and future design of settlements demands cooperative participation between planners, architects, and relevant stakeholders, with the urban and global climate community, which recognizes the complexity of the physical systems involved and is ideally fit to quantitatively examine the viability of proposed solutions. Such participatory efforts can aid the development of locally sensible approaches by integrating across the socioeconomic and climatic continuum, therefore providing opportunities facilitating comprehensive solutions that maximize benefits and limit unintended consequences.

  1. A new electrophoretic technique for determining catecholamines and their metabolites under the conditions of micellar electrokinetic chromatography format

    Microsoft Academic Search

    L. A. Kartsova; O. V. Ganzha

    2009-01-01

    It is shown that reversed-flow micellar electrokinetic chromatography in buffer electrolyte solutions with pH < 2.5 can be\\u000a used to determine catecholamines and their metabolites. The effect of ion-pair (sodium octane sulfonate) and complexing agent\\u000a (18-crown-6 and 4,13-diaza-18-crown-6) concentrations on the efficiency and selectivity of the separation of biological amines\\u000a is studied. Complex formation in the macrocycle-analyte system is quantitatively

  2. Separation of polynuclear aromatic hydrocarbons by micellar electrokinetic capillary chromatography using sodium taurodeoxycholate modified with organic solvents.

    PubMed

    Dabek-Zlotorzynska, E; Lai, E P

    1996-01-01

    The usefulness of a bile acid salt, sodium taurodeoxycholate (STDC), as a surfactant and organic solvents as organic modifiers for the separation of 16 polynuclear aromatic hydrocarbons (PAHs) on the U.S. EPA priority pollutant list by micellar electrokinetic capillary chromatography (MEKC) was investigated. The best resolution of analytes was obtained with a phosphate-borate buffer containing 50 mM STDC and 30% acetone. Short capillaries effected rapid (< 6 min) partial PAH separation, an approach that has potential use in screening studies. The capability of the developed separation system was demonstrated in the analysis of ambient air extracts. PMID:9384762

  3. Different effects of BrdU and 3H-Thymidine incorporation into DNA on cell proliferation, position and fate

    PubMed Central

    Duque, Alvaro; Rakic, Pasko

    2011-01-01

    As markers of DNA synthesis, 3H-Thymidine (3H-dT), and the later developed analog, Bromodeoxyuridine (BrdU) have revolutionized our ability to identify dividing cells and follow their fate in various tissues, including the nervous system. However, the effect of the incorporation of these molecules into DNA on cell proliferation, migration, differentiation and function is not fully understood. Here, we compare the number and distribution of labeled cells in the cerebral cortex of postnatal macaque monkeys exposed to either 3H-dT or BrdU as embryos. The large size and prolonged brain development in this species allows higher resolution of cellular events and more accurate discrimination between the two methods. Our analysis revealed substantial differences in the number and distribution of labeled cells. The data indicate that random incorporation of the thymidine analogue BrdU into the genes of dividing cells makes the fate of postmitotic neurons more prone to unpredictable errors than the incorporation of the more natural DNA constituent nucleotide 3H-dT. These findings have implications for the interpretation of results obtained by BrdU as an index of the number of neurons produced, their migration, placement, subsequent connectivity, function and survival. PMID:22016554

  4. Effect of Vanadium Incorporation on Electrochemical Performance of LiFePO(4) for Lithium-Ion Batteries

    SciTech Connect

    L Zhang; G Liang; A Ignatov; M Croft; X Xiong; I Hung; Y Huang; X Hu; W Zhang; Y Peng

    2011-12-31

    A series of LiFe{sub 1-x}V{sub x}PO{sub 4}/C samples have been successfully prepared using a two-step solid-state reaction route. The effect of vanadium incorporation on the performance of LiFePO{sub 4} has systematically been investigated with X-ray diffraction, Raman spectroscopy, charge/discharge measurements, and cyclic voltammetry tests. It is found that V incorporation significantly enhances the electrochemical performance of LiFePO{sub 4}. Particularly, the LiFePO{sub 4}/C sample with 5 at. % vanadium doping exhibits the best performance with a specific discharge capacity of 129 mAh g{sup -1} at 5.0 C after 50 cycles; the capacity retention ratio is higher than 97.5% at all C rates from 0.1 to 5.0 C. X-ray absorption spectroscopy results show that the valence of V in LiFe{sub 0.95}V{sub 0.05}PO{sub 4}/C is between +3 and +4. It is confirmed that the samples with x {le} 0.03 are in single phase, whereas the samples with 0.05 {le} x < 1.00 contain two impurity phases: Li{sub 3}V{sub 2}(PO{sub 4}){sub 3} and LiVOPO{sub 4}. A clear feature of vanadium incorporation in LiFePO{sub 4} has been specified.

  5. Effect of nickel incorporation on microstructural and optical properties of electrodeposited diamond like carbon (DLC) thin films

    NASA Astrophysics Data System (ADS)

    Pandey, B.; Pal, P. P.; Bera, S.; Ray, S. K.; Kar, A. K.

    2012-11-01

    A simple electrodeposition technique was used to synthesize diamond like carbon (DLC) and nickel incorporated diamond like carbon (Ni-DLC) thin films on ITO coated glass substrates. Initial concentration of nickel in the electrolyte was kept fixed at 4.76 × 10-4 M for all depositions of Ni-DLC films. Growth process of the films was studied by synthesizing films with variation of deposition time. With nickel addition to DLC the band gap and the Urbach energy varied from 2.67 eV to 2.48 eV and 1.0803 eV to 1.452 eV, respectively as estimated from UV-vis-NIR spectrophotometry of DLC and Ni-DLC. Results indicated that the metal incorporation effectively increased the graphitization of DLC films. Microstructural studies by SEM and AFM revealed that the particles in the Ni-DLC films were evenly distributed and the packing density of particles increased with increased time of deposition. XRD pattern exhibited the presence of Ni crystallites in an amorphous carbon network along with the phases of diamond and graphite in the Ni-DLC film. The FTIR spectrum showed peaks accountable for both CH3 and CH2 bonding. It was also apparent that nickel incorporation significantly modulated the FTIR spectrum of DLC film, as several new peaks appeared only in the case of Ni-DLC film at ˜776 cm-1, 745 cm-1 and 668 cm-1.

  6. The effect of direct PAG incorporation into the polymer main chain on reactive ion etch resistance of 193 nm and EUV chemically amplified resists

    Microsoft Academic Search

    Cheng-Tsung Lee; Clifford L. Henderson; Mingxing Wang; Kenneth E. Gonsalves; Wang Yueh; Jeanette M. Roberts

    2008-01-01

    The incorporation of photoacid generator (PAG) functional groups directly into the resist resin polymer backbone has shown improved lithographic performance in achieving high resolution, high sensitivity, and low line edge roughness (LER) simultaneously in chemically amplified resists. However, the effect of direct PAG incorporation into the resist polymer on the reactive ion etch (RIE) performance in such materials was not

  7. Effect of Bi incorporation on the carrier mobility in the dilute bismide alloy, GaAsBi

    NASA Astrophysics Data System (ADS)

    Kini, Rajeev; Ptak, Aaron; France, Ryan; Mascarenhas, Angelo

    2010-03-01

    Results from our study of carrier mobilities in doped GaAs1-xBix epilayers will be presented and compared with the dilute nitride alloy, GaAsN. We observed no significant degradation in the electron mobility with Bi incorporation in GaAs, up to a concentration of 1.2%. At higher Bi concentration (>=1.6%) some degradation of the electron mobility was observed, although there is no apparent trend. Temperature dependant Hall measurements of the electron mobility suggest neutral impurity scattering to be the dominant scattering mechanism. We will also present data on the effect of Bi alloying on the hole mobility.

  8. Effects of retroviral envelope-protein cleavage upon trafficking, incorporation, and membrane fusion

    SciTech Connect

    Apte, Swapna, E-mail: apte@purdue.ed [Department of Biological Sciences, Purdue University, West Lafayette, IN 47907-1392 (United States); Sanders, David Avram, E-mail: retrovir@purdue.ed [Department of Biological Sciences, Purdue University, West Lafayette, IN 47907-1392 (United States)

    2010-09-15

    Retroviral envelope glycoproteins undergo proteolytic processing by cellular subtilisin-like proprotein convertases at a polybasic amino-acid site in order to produce the two functional subunits, SU and TM. Most previous studies have indicated that envelope-protein cleavage is required for rendering the protein competent for promoting membrane fusion and for virus infectivity. We have investigated the role of proteolytic processing of the Moloney murine leukemia virus envelope-protein through site-directed mutagenesis of the residues near the SU-TM cleavage site and have established that uncleaved glycoprotein is unable either to be incorporated into virus particles efficiently or to induce membrane fusion. Additionally, the results suggest that cleavage of the envelope protein plays an important role in intracellular trafficking of protein via the cellular secretory pathway. Based on our results it was concluded that a positively charged residue located at either P2 or P4 along with the arginine at P1 is essential for cleavage.

  9. Electrokinetic concentration of DNA polymers in nanofluidic channels.

    PubMed

    Stein, Derek; Deurvorst, Zeno; van der Heyden, Frank H J; Koopmans, Wiepke J A; Gabel, Alan; Dekker, Cees

    2010-03-10

    DNA molecules can be concentrated in a narrow region of a nanochannel when driven electrokinetically in submillimolar salt solutions. Transport experiments and theoretical modeling reveal the interplay of electrophoresis, electro-osmosis, and the unique statistical properties of confined polymers that lead to DNA aggregation. A finite conductance through the bulk of the device also plays a crucial role by influencing the electric fields in the nanochannel. We build on this understanding by demonstrating how a nanofluidic device with integrated electrodes can preconcentrate DNA at selected locations and at physiological salt concentrations that are relevant to lab-on-a-chip applications. PMID:20151696

  10. Electrokinetic instability near charge-selective hydrophobic surfaces

    NASA Astrophysics Data System (ADS)

    Shelistov, V. S.; Demekhin, E. A.; Ganchenko, G. S.

    2014-07-01

    The influence of the texture of a hydrophobic surface on the electro-osmotic slip of the second kind and the electrokinetic instability near charge selective surfaces (permselective membranes, electrodes, or systems of microchannels and nanochannels) is investigated theoretically using a simple model based on the Rubinstein-Zaltzman approach. A simple formula is derived to evaluate the decrease in the instability threshold due to hydrophobicity. The study is complemented by numerical investigations both of linear and nonlinear instabilities near a hydrophobic membrane surface. Theory predicts a significant enhancement of the ion flux to the surface and shows a good qualitative agreement with the available experimental data.

  11. Determination of ginsenosides from Panax ginseng using micellar electrokinetic chromatography.

    PubMed

    Glöckl, Ingmar; Veit, Markus; Blaschke, Gottfried

    2002-02-01

    A method for determination of ginsenosides in herbal medicinal products (HMPs) was developed using micellar electrokinetic chromatography (MEKC). Within 22 minutes 7 major ginsenosides were well separated. In order to demonstrate the accuracy, precision and robustness for the main target analyte the method was exemplarily validated for the determination of Rb1 according to ICH guidelines. Compared to chromatographic analysis, several benefits of capillary electrophoresis (CE) could be demonstrated such as high separation efficiency in an aqueous buffer without any organic solvent and shorter run time per assay. PMID:11859468

  12. Field Testing of High Current Electrokinetic Nanoparticle Treatment for Corrosion Mitigation in Reinforced Concrete

    NASA Technical Reports Server (NTRS)

    Cardenas, Henry; Alexander, Joshua; Kupwade-Patil, Kunal; Calle, Luz marina

    2010-01-01

    Electrokinetic Nanoparticle (EN) treatment was used as a rapid repair measure to mitigate chloride induced corrosion of reinforced concrete in the field. EN treatment uses an electric field to transport positively charged nanoparticles to the reinforcement through the concrete capillary pores. Cylindrical reinforced concrete specimens were batched with 4.5 wt % salt content (based on cement mass). Three distinct electrokinetic treatments were conducted using high current density (up to 5 A/m2) to form a chloride penetration barrier that was established in 5 days, as opposed to the traditional 6-8 weeks, generally required for electrochemical chloride extraction (ECE). These treatments included basic EN treatment, EN with additional calcium treatment, and basic ECE treatment. Field exposures were conducted at the NASA Beachside Corrosion Test Site, Kennedy Space Center, Florida, USA. The specimens were subjected to sea water immersion at the test site as a posttreatment exposure. Following a 30-day post-treatment exposure period, the specimens were subjected to indirect tensile testing to evaluate treatment impact. The EN treated specimens exhibited 60% and 30% increases in tensile strength as compared to the untreated controls and ECE treated specimens respectively. The surfaces of the reinforcement bars of the control specimens were 67% covered by corrosion products. In contrast, the EN treated specimens exhibited corrosion coverage of only 4%. Scanning electron microscopy (SEM) revealed a dense concrete microstructure adjacent to the bars of the treated specimens as compared to the control and ECE specimens. Energy dispersive spectroscopic (EDS) analysis of the polished EN treated specimens showed a reduction in chloride content by a factor of 20 adjacent to the bars. This study demonstrated that EN treatment was successful in forming a chloride penetration barrier rapidly. This work also showed that the chloride barrier was effective when samples were exposed to field conditions at one of the most severely corrosive environments in North America.

  13. Effect of ambient storage on the quality characteristics of aerobically packaged fish curls incorporated with different flours.

    PubMed

    Raja, Waseem Hussain; Kumar, Sunil; Bhat, Zuhaib Fayaz; Kumar, Pavan

    2014-01-01

    The present study was conducted to evaluate the effect of ambient storage on the quality attributes of aerobically packaged fish curls incorporated with optimum levels of different flours. The curls were developed by extrusion technology using fish meat (Catla catla). The fish curls containing optimum levels of different flours viz. 20 percent corn flour, 10 percent black gram flour and 10 percent peanut flour were compared with the control snacks containing 30 percent rice flour and assessed for storage quality and shelf life at ambient temperature. The curls were aerobically packaged in LDPE (low density polyethylene) pouches and evaluated for various physicochemical, microbiological and sensory parameters. Mean values of pH of all the curls showed significantly (p?incorporated samples, 6.36?±?0.01 on day 0 and 6.14?±?0.01 on day 28 for black gram flour incorporated samples, 6.57?±?0.007 on day 0 and 6.34?±?0.01 on day 28 for peanut flour incorporated samples). TBARS (mg malonaldehyde/kg), total plate count (log cfu/g) and yeast and mould count (log cfu/g) for the control as well as treatment samples showed significantly (p?incorporated with optimum level of different flours were acceptable up to 21 days of ambient storage within the LDPE pouches. PMID:24624316

  14. Bacterial surface appendages strongly impact nanomechanical and electrokinetic properties of Escherichia coli cells subjected to osmotic stress.

    PubMed

    Francius, Grégory; Polyakov, Pavel; Merlin, Jenny; Abe, Yumiko; Ghigo, Jean-Marc; Merlin, Christophe; Beloin, Christophe; Duval, Jérôme F L

    2011-01-01

    The physicochemical properties and dynamics of bacterial envelope, play a major role in bacterial activity. In this study, the morphological, nanomechanical and electrohydrodynamic properties of Escherichia coli K-12 mutant cells were thoroughly investigated as a function of bulk medium ionic strength using atomic force microscopy (AFM) and electrokinetics (electrophoresis). Bacteria were differing according to genetic alterations controlling the production of different surface appendages (short and rigid Ag43 adhesins, longer and more flexible type 1 fimbriae and F pilus). From the analysis of the spatially resolved force curves, it is shown that cells elasticity and turgor pressure are not only depending on bulk salt concentration but also on the presence/absence and nature of surface appendage. In 1 mM KNO(3), cells without appendages or cells surrounded by Ag43 exhibit large Young moduli and turgor pressures (?700-900 kPa and ?100-300 kPa respectively). Under similar ionic strength condition, a dramatic ?50% to ?70% decrease of these nanomechanical parameters was evidenced for cells with appendages. Qualitatively, such dependence of nanomechanical behavior on surface organization remains when increasing medium salt content to 100 mM, even though, quantitatively, differences are marked to a much smaller extent. Additionally, for a given surface appendage, the magnitude of the nanomechanical parameters decreases significantly when increasing bulk salt concentration. This effect is ascribed to a bacterial exoosmotic water loss resulting in a combined contraction of bacterial cytoplasm together with an electrostatically-driven shrinkage of the surface appendages. The former process is demonstrated upon AFM analysis, while the latter, inaccessible upon AFM imaging, is inferred from electrophoretic data interpreted according to advanced soft particle electrokinetic theory. Altogether, AFM and electrokinetic results clearly demonstrate the intimate relationship between structure/flexibility and charge of bacterial envelope and propensity of bacterium and surface appendages to contract under hypertonic conditions. PMID:21655293

  15. Rapid and Label-Free Separation of Burkitt's Lymphoma Cells from Red Blood Cells by Optically-Induced Electrokinetics

    PubMed Central

    Liang, Wenfeng; Zhao, Yuliang; Liu, Lianqing; Wang, Yuechao; Dong, Zaili; Li, Wen Jung; Lee, Gwo-Bin; Xiao, Xiubin; Zhang, Weijing

    2014-01-01

    Early stage detection of lymphoma cells is invaluable for providing reliable prognosis to patients. However, the purity of lymphoma cells in extracted samples from human patients' marrow is typically low. To address this issue, we report here our work on using optically-induced dielectrophoresis (ODEP) force to rapidly purify Raji cells' (a type of Burkitt's lymphoma cell) sample from red blood cells (RBCs) with a label-free process. This method utilizes dynamically moving virtual electrodes to induce negative ODEP force of varying magnitudes on the Raji cells and RBCs in an optically-induced electrokinetics (OEK) chip. Polarization models for the two types of cells that reflect their discriminate electrical properties were established. Then, the cells' differential velocities caused by a specific ODEP force field were obtained by a finite element simulation model, thereby established the theoretical basis that the two types of cells could be separated using an ODEP force field. To ensure that the ODEP force dominated the separation process, a comparison of the ODEP force with other significant electrokinetics forces was conducted using numerical results. Furthermore, the performance of the ODEP-based approach for separating Raji cells from RBCs was experimentally investigated. The results showed that these two types of cells, with different concentration ratios, could be separated rapidly using externally-applied electrical field at a driven frequency of 50 kHz at 20 Vpp. In addition, we have found that in order to facilitate ODEP-based cell separation, Raji cells' adhesion to the OEK chip's substrate should be minimized. This paper also presents our experimental results of finding the appropriate bovine serum albumin concentration in an isotonic solution to reduce cell adhesion, while maintaining suitable medium conductivity for electrokinetics-based cell separation. In short, we have demonstrated that OEK technology could be a promising tool for efficient and effective purification of Raji cells from RBCs. PMID:24608811

  16. Effects of straw incorporation along with microbial inoculant on methane and nitrous oxide emissions from rice fields.

    PubMed

    Liu, Gang; Yu, Haiyang; Ma, Jing; Xu, Hua; Wu, Qinyan; Yang, Jinghui; Zhuang, Yiqing

    2015-06-15

    Incorporation of straw together with microbial inoculant (a microorganism agent, accelerating straw decomposition) is being increasingly adopted in rice cultivation, thus its effect on greenhouse gas (GHG) emissions merits serious attention. A 3-year field experiment was conducted from 2010 to 2012 to investigate combined effect of straw and microbial inoculant on methane (CH4) and nitrous oxide (N2O) emissions, global warming potential (GWP) and greenhouse gas intensity (GHGI) in a rice field in Jurong, Jiangsu Province, China. The experiment was designed to have treatment NPK (N, P and K fertilizers only), treatment NPKS (NPK plus wheat straw), treatment NPKSR (NPKS plus Ruilaite microbial inoculant) and treatment NPKSJ (NPKS plus Jinkuizi microbial inoculant). Results show that compared to NPK, NPKS increased seasonal CH4 emission by 280-1370%, while decreasing N2O emission by 7-13%. When compared with NPKS, NPKSR and NPKSJ increased seasonal CH4 emission by 7-13% and 6-12%, respectively, whereas reduced N2O emission by 10-27% and 9-24%, respectively. The higher CH4 emission could be attributed to the higher soil CH4 production potential triggered by the combined application of straw and microbial inoculant, and the lower N2O emission to the decreased inorganic N content. As a whole, the benefit of lower N2O emission was completely offset by increased CH4 emission, resulting in a higher GWP for NPKSR (5-12%) and NPKSJ (5-11%) relative to NPKS. Due to NPKSR and NPKSJ increased rice grain yield by 3-6% and 2-4% compared to NPKS, the GHGI values for NPKS, NPKSR and NPKSJ were comparable. These findings suggest that incorporating straw together with microbial inoculant would not influence the radiative forcing of rice production in the terms of per unit of rice grain yield relative to the incorporation of straw alone. PMID:25756676

  17. A chemical mechanical polishing model incorporating both the chemical and mechanical effects

    Microsoft Academic Search

    Kuide Qin; Brij Moudgil; Chang-Won Park

    2004-01-01

    A comprehensive model for the material removal in a chemical mechanical polishing (CMP) process is presented in which both chemical and mechanical effects are taken into consideration. The chemical effects come into play through the formation of chemically modified surface layer on the wafer surface that, in turn, is removed mechanically by the plastic deformation induced by slurry particles. This

  18. Incorporating dose-rate effects in Markov radiation cell survival models.

    PubMed

    Sachs, R K; Hlatky, L; Hahnfeldt, P; Chen, P L

    1990-11-01

    Markov models for the survival of cells subjected to ionizing radiation take stochastic fluctuations into account more systematically than do non-Markov counterparts. Albright's Markov RMR (repair-misrepair) model (Radiat. Res. 118, 1-20, 1989) and Curtis's Markov LPL (lethal-potentially lethal) model [in Quantitative Mathematical Models in Radiation Biology (J. Kiefer, Ed.), pp. 127-146. Springer, New York, 1989], which assume acute irradiation, are here generalized to finite dose rates. Instead of treating irradiation as an instantaneous event we introduce an irradiation period T and analyze processes during the interval T as well as afterward. Albright's RMR transition matrix is used throughout for computing the time development of repair and misrepair. During irradiation an additional matrix is added to describe the evolving radiation damage. Albright's and Curtis's Markov models are recovered as limiting cases by taking T----0 with total dose fixed; the opposite limit, of low dose rates, is also analyzed. Deviations from Poisson behavior in the statistical distributions of lesions are calculated. Other continuous-time Markov chain models ("compartmental models") are discussed briefly, for example, models which incorporate cell proliferation and saturable repair models. It is found that for low dose rates the Markov RMR and LPL models give lower survivals compared to the original non-Markov versions. For acute irradiation and high doses, the Markov models predict higher survivals. In general, theoretical extrapolations which neglect some random fluctuations have a systematic bias toward overoptimism when damage to irradiated tumors is compared with damage to surrounding tissues. PMID:2247602

  19. Antibacterial effect of a resin incorporating a novel polymerizable quaternary ammonium salt MAE-DB against Streptococcus mutans.

    PubMed

    Huang, Li; Sun, Xiang; Xiao, Yu-Hong; Dong, Yan; Tong, Zhong-Chun; Xing, Xiao-Dong; Li, Fang; Chai, Zhi-Guo; Chen, Ji-Hua

    2012-07-01

    The antibacterial properties of resins incorporating MAE-DB and the underlying mechanisms of action were evaluated. Antibacterial effects against Streptococcus mutans were tested using the film contact method, with accumulation and membrane integrity observed by scanning electron microscopy and confocal laser scanning microscopy, respectively. Quantitative PCR was used to determine expression of the S. mutans glucosyltransferase B (gtfB) gene on the surface of resins containing 10% MAE-DB. Bacterial growth was inhibited on resin containing 10% MAE-DB as compared with the control at 1 day, 7 days, 30 days, or 180 days (p < 0.05). For the 10%-MAE-DB resin, no significant differences in bacterial viability were found regardless of the time of incubation (p > 0.05). The number of bacteria attached to resin containing 10% MAE-DB was considerably lower than the control. The proportion of bacteria with damaged cell membranes was increased in the experimental resin over controls. Expression of gtfB was reduced by 10% MAE-DB compared with the control (p < 0.05). These findings demonstrate that MAE-DB can be incorporated into resin materials at sufficient concentrations for long-term antibacterial effects against S. mutans after polymerization by attenuating gtfB expression and impairing membrane integrity. PMID:22566399

  20. Incorporation of analgesics into rodent embryo transfer protocols: assessing the effects on reproductive outcomes 

    E-print Network

    Burckhardt, Heather Ann

    2009-05-15

    Surgical embryo transfer in rodents is a common procedure in today’s research laboratory, although little is known of the effect analgesics may have on not only the recipient female but also the embryos. Two perioperative analgesics, ketoprofen...

  1. A METHOD TO INCORPORATE ECOLOGY INTO RESIDENCE TIME OF CHEMICALS IN EMBAYMENTS: LOCAL EFFECT TIME

    EPA Science Inventory

    Residence times are classically defined by the physical and chemical aspects of water bodies rather than by their ecological implications. Therefore, a more clear and direct connection between the residence times and ecological effects is necessary to quantitatively relate these ...

  2. An analytical framework for field electron emission, incorporating quantum- confinement effects

    E-print Network

    Patterson. Alex A. (Alex Andrew)

    2013-01-01

    As field electron emitters shrink to nanoscale dimensions, the effects of quantum confinement of the electron supply and electric field enhancement at the emitter tip play a significant role in determining the emitted ...

  3. Incorporating LASSO effects into a mixed model for quantitative trait loci detection

    Microsoft Academic Search

    Scott D. Foster; Ar?nas P. Verbyla; Wayne S. Pitchford

    2007-01-01

    The identification of quantitative trait loci (QTL) can be viewed as a subset selection problem. In a simulation study the\\u000a least absolute selection and shrinkage operator (LASSO) is shown to be a useful and powerful tool for QTL identification.\\u000a LASSO effects are embedded into a mixed model allowing simultaneous modeling of genetic and experimental effects. This provides\\u000a the flexibility to

  4. Incorporation of Competitive Effects in Forest Tree or Animal Breeding Programs

    PubMed Central

    Muir, William M.

    2005-01-01

    Competition among domesticated plants or animals can have a dramatic negative impact on yield of a stand or farm. The usual quantitative genetic model ignores these competitive interactions and could result in seriously incorrect breeding decisions and acerbate animal well-being. A general solution to this problem is given, for either forest tree breeding or penned animals, with mixed-model methodology (BLUP) utilized to separate effects on the phenotype due to the individuals' own genes (direct effects) and those from competing individuals (associative effects) and thereby to allow an optimum index selection on those effects. Biological verification was based on two lines of Japanese quail selected for 6-week weight; one line was selected only for direct effects (D-BLUP) while the other was selected on an optimal index for both direct and associative effects (C-BLUP). Results over 23 cycles of selection showed that C-BLUP produced a significant positive response to selection (b = 0.52 ± 0.25 g/hatch) whereas D-BLUP resulted in a nonsignificant negative response (b = ?0.10 ± 0.25 g/hatch). The regression of percentage of mortality on hatch number was significantly different between methods, decreasing with C-BLUP (b = ?0.06 ± 0.15 deaths/hatch) and increasing with D-BLUP (b = 0.32 ± 0.15 deaths/hatch). These results demonstrate that the traditional D-BLUP approach without associative effects not only is detrimental to response to selection but also compromises the well-being of animals. The differences in response show that competitive effects can be included in breeding programs, without measuring new traits, so that costs of the breeding program need not increase. PMID:15911590

  5. Importance of Electrokinetic Phenomena in Contamination Control during Semiconductor Wet Processing.

    NASA Astrophysics Data System (ADS)

    Jan, Der-E.

    The adsorption of metanil yellow (3- {{4-(phenylamino) phenyl }azo} benzene sulfonate) and colloidal silica on a commercially available, positively charge-modified nylon 66 membrane (N66 Posidyne) with an isoelectric point (IEP) of 7.6 was investigated. Challenge testing of N66 Posidyne with a 2.3 ppm colloidal silica dispersion has shown that the membrane adsorbed 0.015 mug of colloidal silica per cm ^2. At a pH of 5.1, the adsorption of metanil yellow was found to increase with its solution concentration and reached a saturation value of 2.2 times 10^{14} ions/cm ^2 at a solution concentration of 1.49 times 10^{ -5}M. A technique to incorporate positively charged groups onto the surface of microporous polypropylene and polyvinylidene fluoride membrane filters for the filtration of liquids used in the semiconductor industry has been developed using gamma-irradiation. The electrical characteristics of prepared membranes were measured by streaming potential and dye challenge tests. The compatibility of these charge-modified membranes with ultrapure water was investigated. Results show that these charge-modified membranes are characterized by a positive zeta potential in the pH range from 4 to 9.3. From the dye challenge tests at a pH of 5.0, the density of positively charged sites on charge-modified membranes was calculated to be approximately five times larger than that of unmodified membranes. The modified membranes released less than 1 ppb of total organic carbon (TOC) into ultrapure water and thus appear to have potential for use in DI water system. The electrokinetic characteristics of silicon, silicon dioxide and silicon nitride wafers subjected to different cleaning procedures were measured using a streaming potential technique. A streaming potential cell for handling 5^{''} wafers was designed and fabricated to make these measurements. The isoelectric point of silicon, silicon dioxide and silicon nitride was dependent on the cleaning method. Polystyrene latex (PSL) and aminopropyl/silica particle deposition from aqueous solutions onto silicon nitride was investigated and correlated with the electrokinetic potential data.

  6. Effects of high frequency ultrasound irradiation on incorporation of SiO2 particles within polypyrrole films.

    PubMed

    Grari, O; Dhouibi, L; Lallemand, F; Buron, C C; Et Taouil, A; Hihn, J Y

    2015-01-01

    This paper deals with the effect of ultrasound on polypyrrole/SiO2 composite film elaboration through various steps (particle dispersion, electrosynthesis). Experiments were carried out on stainless steel in phosphoric acid solution. An efficient method for dispersion of SiO2 particles prior to electropolymerization, based on low frequency irradiation (20kHz), was proposed. It was shown that mechanical effects of high frequency ultrasound (i.e. mass transfer improvement) led to enhancement of electropolymerization kinetics. Scanning electron microscopy imaging and glow discharge optical emission spectroscopy revealed localization of SiO2 particles in the outer region of the films as well as better incorporation of particles under high frequency ultrasound irradiation. Finally, anticorrosion behavior of formed films was investigated in sodium chloride solution by Open Circuit Potential and anodic polarization methods. The results showed that polypyrrole/SiO2 films elaborated under ultrasound irradiation exhibit the best protective performances. PMID:24835022

  7. Electrokinetic preconcentration of particles and cells in microfluidic reservoirs.

    PubMed

    Harrison, Herbert; Lu, Xinyu; Patel, Saurin; Thomas, Cory; Todd, Andrew; Johnson, Mark; Raval, Yash; Tzeng, Tzuen-Rong; Song, Yongxin; Wang, Junsheng; Li, Dongqing; Xuan, Xiangchun

    2015-04-21

    Preconcentrating samples of dilute particles or cells to a detectable level is required in many chemical, environmental and biomedical applications. A variety of force fields have thus far been demonstrated to capture and accumulate particles and cells in microfluidic devices, which, however, all take place within the region of microchannels and may potentially cause channel clogging. This work presents a new method for the electrokinetic preconcentration of 1 ?m-diameter polystyrene particles and E. coli cells in a very-low-conductivity medium inside a microfluidic reservoir. The entire microchannel can hence be saved for a post-concentration analysis. This method exploits the strong recirculating flows of induced-charge electroosmosis to concentrate particles and cells near the corners of the reservoir-microchannel interface. Positive dielectrophoresis is found to also play a role when small microchannels are used at high electric fields. Such an in-reservoir electrokinetic preconcentration method can be easily implemented in a parallel mode to increase the flow throughput, which may potentially be used to preconcentrate bacterial pathogens in water. PMID:25742630

  8. Monolayers of poly-l-lysine on mica - Electrokinetic characteristics.

    PubMed

    Morga, Maria; Adamczyk, Zbigniew; Gödrich, Sebastian; O?wieja, Magdalena; Papastavrou, Georg

    2015-10-15

    Physicochemical properties of poly-l-lysine and its monolayers on mica were thoroughly investigated by dynamic light scattering, electrokinetic methods and atomic force microscopy. The hydrodynamic diameter of PLL was equal to 25.5nm within a wide range of pH and ionic strength. The electrophoretic measurements revealed that the molecules are positively charged for pH<10.5. By exploiting the electrophoretic mobility data, theelectrokinetic charge on the PLL molecules and their zeta potential were calculated. PLL monolayers of controlled coverage were deposited on mica under diffusion-controlled conditions by varying PLL bulk concentration and adsorption time. The electrokinetic characteristics of the monolayers were acquired in situ via streaming potential measurements. These studies allowed to uniquely determine the zeta potential of the monolayers as a function of pH and ionic strength. In this way the isoelectric point of the monolayers can be determined in a more convenient way compared to bulk measurements disturbed by the PLL molecule interactions. The stability of the monolayers under flow conditions was quantitatively evaluated via streaming potential measurements. The adsorption constant and the binding energy depth of PLL molecules were determined for different ionic strengths. These parameters indicate that the PLL monolayers remain stable over prolonged times. PMID:26115031

  9. An improved analytical model of 4H-SiC MESFET incorporating bulk and interface trapping effects

    NASA Astrophysics Data System (ADS)

    Hema Lata Rao, M.; Narasimha Murty, N. V. L.

    2015-01-01

    An improved analytical model for the current—voltage (I–V) characteristics of the 4H-SiC metal semiconductor field effect transistor (MESFET) on a high purity semi-insulating (HPSI) substrate with trapping and thermal effects is presented. The 4H-SiC MESFET structure includes a stack of HPSI substrates and a uniformly doped channel layer. The trapping effects include both the effect of multiple deep-level traps in the substrate and surface traps between the gate to source/drain. The self-heating effects are also incorporated to obtain the accurate and realistic nature of the analytical model. The importance of the proposed model is emphasised through the inclusion of the recent and exact nature of the traps in the 4H-SiC HPSI substrate responsible for substrate compensation. The analytical model is used to exhibit DC I–V characteristics of the device with and without trapping and thermal effects. From the results, the current degradation is observed due to the surface and substrate trapping effects and the negative conductance introduced by the self-heating effect at a high drain voltage. The calculated results are compared with reported experimental and two-dimensional simulations (Silvaco®-TCAD). The proposed model also illustrates the effectiveness of the gate—source distance scaling effect compared to the gate—drain scaling effect in optimizing 4H-SiC MESFET performance. Results demonstrate that the proposed I–V model of 4H-SiC MESFET is suitable for realizing SiC based monolithic circuits (MMICs) on HPSI substrates.

  10. Ramp-rate limits in unit commitment and economic dispatch incorporating rotor fatigue effect

    Microsoft Academic Search

    C. Wang; S. M. Shahidehpour

    1994-01-01

    In this study, a rigorous mathematical method is proposed for dealing with the ramp-rate limits in unit commitment and the rotor fatigue effect in economic dispatch. An iterative procedure is employed to coordinate the unit commitment and the power dispatch for obtaining an economical solution within a reasonable time. The Lagrangian relaxation method is used to generate the unit commitment

  11. Illuminating reform evaluation studies through incorporating teacher effectiveness research: A case study in mathematics

    Microsoft Academic Search

    L. Kyriakides; C. Charalambous; G. Philippou; R. J. Campbell

    2006-01-01

    The goal of the present study was twofold: first to examine teachers' and students' reactions toward a mathematics reform introduced in Cypriot primary schools, and second to investigate the factors influencing the effectiveness of the reform. Using both quantitative and qualitative data we found that students' progress was determined by a number of factors related to teachers' and students' personal

  12. An effective method of Cu incorporation in CdTe solar cells for improved stability

    Microsoft Academic Search

    S. Erra; C. Shivakumar; H. Zhao; K. Barri; D. L. Morel; C. S. Ferekides

    2007-01-01

    Thin film CdTe solar cells of the superstrate configuration have been fabricated in order to study the effect of Cu on device stability. The study focused on two distinct sets of solar cells: in one set of devices Cu was introduced during the formation of the back contact, by sputtering a small thickness of Cu onto the CdTe surface prior

  13. Considerations for Incorporating Bioavailability in Effect-Directed Analysis and Toxicity Identification Evaluation.

    EPA Science Inventory

    In order to avoid a bias toward highly toxic but poorly bioavailable compounds in the effect-directed analysis (EDA) of soils and sediments, approaches are discussed to consider bioavailability in EDA procedures. In parallel, complimentary approaches for making toxicity identific...

  14. The effect of flooding and residue incorporation on soil chemistry, germination and seedling growth

    Microsoft Academic Search

    Irene M. Unger; Rose-Marie Muzika; Peter P. Motavalli

    2010-01-01

    Anaerobic soil conditions created during flood events may alter soil chemistry. Increased concentrations of phenolic compounds and decreased soil inorganic nitrogen may occur, with subsequent negative effects on seed germination and seedling growth. We investigated these relationships under greenhouse conditions using simulated floods with stagnant, flowing or intermittent flood waters. These flood experiments were followed by germination tests using Virginia

  15. Antioxidant Effects of Berry Phenolics Incorporated in Oil-in-Water Emulsions with Continuous Phase ?-Lactoglobulin

    Microsoft Academic Search

    Hanna Salminen; Marina Heinonen; Eric A. Decker

    2010-01-01

    The purpose of this study was to evaluate the effects of berry phenolics, in this case, black currant (Ribes nigrum) anthocyanins and raspberry (Rubus idaeus) ellagitannins, in the presence of continuous phase ?-lactoglobulin (?-Lg), on the oxidative stability of Brij 35-stabilized\\u000a corn oil-in-water emulsions. The extent of lipid oxidation in emulsions was measured by determining the formation of lipid\\u000a hydroperoxides

  16. A cost effective technique for incorporating distributed control system concepts into the undergraduate curriculum

    Microsoft Academic Search

    A. E. Leybourne; K. S. Ali

    1996-01-01

    The electronics and computer engineering programs at the University of Southern Mississippi offer two process control courses. One is based on classical continuous domain techniques while the other utilizes the domain. Historically, Distributed Process (DPC) tasks have required main-frame or mini-computers, usually with proprietary software. Our experience with an LC-4 Controller (micro-computer) which has been effectively utilized in the discrete

  17. Release property and antioxidant effectiveness of tocopherol-incorporated LDPE\\/PP blend films

    Microsoft Academic Search

    X. Zhu; D. S. Lee; K. L. Yam

    2012-01-01

    Low-density polyethylene (LDPE)\\/polypropylene (PP) blend films in various blending ratios containing 3000?mg?kg of tocopherol were manufactured by an extrusion process. Tocopherol release properties were characterised and correlated with antioxidant effectiveness in retarding the oxidation of linoleic acid contacting the films at 40°C. The conditions without tocopherol (control) and with instant tocopherol addition corresponding to the amount included in the films

  18. Development of an integrated, in-situ remediation technology: Task 2--4, electrokinetic modeling. Topical report, September 26--May 25, 1996

    SciTech Connect

    NONE

    1997-05-01

    This report summarizes the work conducted in Tasks 2-4, which together make up the Electrokinetic Modeling carried out in this project. The modeling was divided into three main sections: thermal analysis, chemical species transport, and electrode geometry and soil heterogeneity issues. The thermal modeling consisted of development of the governing equations to incorporate Joule heating associated with electro-osmosis, heat conduction and convection, and temperature dependencies of electrical conductivity and electro-osmotic permeability. To model the transport of chemical species in the Lasagna{sup TM} process, a one-dimensional model was developed. This model is based on previous models, but includes additional mechanism to account for charge transfer in the double layer, pH buffering of the soil, and zeta potential dependency on pH and ionic strength. The results of this model and the corroboration by experimental measurement support some key assumptions made in the thermal model. An analysis was also conducted to compare the use of cylindrical electrodes to the plate geometry used in Phase I. In summary, cylindrical electrodes may be appropriate for anodes, because the do not intercept the flow. If used as cathodes, a planar treatment zone in their vicinity would probably be required. The cylindrical electrodes can operate at reasonable current densities without boiling water. Because the hottest region is at the electrode, cooling schemes could be used to operate at higher current densities. If iron anodes are used, they will have to be quite massive, and may not be economical compared to planar models. An example of soil heterogeneity was investigated when it was discovered that a steel pt was buried in the vicinity of the pilot test. There is some distortion of the field near the pit, but its effects on the test zone between the electrodes are minimal.

  19. Effects of Straw Incorporation on Soil Organic Matter and Soil Water-Stable Aggregates Content in Semiarid Regions of Northwest China

    PubMed Central

    Jia, Zhikuan; Han, Qingfang; Ren, Xiaolong; Li, Yongping

    2014-01-01

    The soil degradation caused by conventional tillage in rain-fed areas of northwest China is known to reduce the water–use efficiency and crop yield because of reduced soil porosity and the decreased availability of soil water and nutrients. Thus, we investigated the effects of straw incorporation on soil aggregates with different straw incorporation rates in semiarid areas of southern Ningxia for a three-year period (2008–2010). Four treatments were tested: (i) no straw incorporation (CK); (ii) incorporation of maize straw at a low rate of 4 500 kg ha?1 (L); (iii) incorporation of maize straw at a medium rate of 9000 kg ha?1 (M); (iv) incorporation of maize straw at a high rate of 13 500 kg ha?1 (H). The results in the final year of treatments (2010) showed that the mean soil organic carbon storage of the 0–60 cm soil layers were significantly (P<0.05) increased with H, M, and L, by 21.40%, 20.38% and 8.21% compared with CK, respectively. Straw incorporation increased >0.25 mm water-stable macroaggregates level, geometric mean diameter, mean weight diameter and the aggregate stability, which were ranked in order of increasing straw incorporation rates: H/M > L > CK. Straw incorporation significantly (P<0.05) reduced the fractal dimension in the 0–40 cm soil layers compared with CK. Our results suggest that straw incorporation is an effective practice for improving the soil aggregate structure and stability. PMID:24663096

  20. Investigation of Microflow Reversal by AC Electrokinetics in Orthogonal Electrodes for Micropump Design

    E-print Network

    Wu, Jayne

    1 Investigation of Microflow Reversal by AC Electrokinetics in Orthogonal Electrodes for Micropump microflows when excited by AC signals, showing potential for micropumping applications. This paper investigates the microflow reversal phenomena in such orthogonal electrode micropumps. Three types of microflow

  1. Towards an understanding of induced-charge electrokinetics at large applied voltages in concentrated solutions

    E-print Network

    Bazant, Martin Z.

    The venerable theory of electrokinetic phenomena rests on the hypothesis of a dilute solution of point-like ions in quasi-equilibrium with a weakly charged surface, whose potential relative to the bulk is of order the ...

  2. Increasing the Sensitivity of Enzyme-Linked Immunosorbent Assay Using Multiplexed Electrokinetic Concentrator

    E-print Network

    Cheow, Lih Feng

    We developed a novel method to increase the sensitivity of standard enzyme-linked immunosorbent assay (ELISA) using a multiplexed electrokinetic concentration chip. The poly(dimethylsiloxane) (PDMS) molecular concentrator(1) ...

  3. Effect of incorporating rape seed oil on quality of ice cream

    Microsoft Academic Search

    M. Nadeem; M. Abdullah; M. Y. Ellahi

    2010-01-01

    A study was carried out to determine the effects of use of rape seed oil in the production of ice cream. The basic ice cream,\\u000a i.e., control (C) had 4.5% milk fat, 11.75% MSNF, 1.25% whey protein concentrate-70 (WPC-70), 15% sucrose, 0.2% sodium alginate,\\u000a and 0.2% glycerol monostearate with a total solids content of 32.9%, vanilla flavored ice cream was

  4. Ramp-rate limits in unit commitment and economic dispatch incorporating rotor fatigue effect

    SciTech Connect

    Wang, C.; Shahidehpour, S.M. (Illinois Inst. of Tech., Chicago, IL (United States). Dept. of Electrical and Computer Engineering)

    1994-08-01

    In this study, a rigorous mathematical method is proposed for dealing with the ramp-rate limits in unit commitment and the rotor fatigue effect in economic dispatch. An iterative procedure is employed to coordinate the unit commitment and the power dispatch for obtaining an economical solution within a reasonable time. The Lagrangian relaxation method is within a reasonable time. The Lagrangian relaxation method is used to generate the unit commitment schedule with relaxed power balance constraints. A network model is adopted to represent the dynamic process of operating a unit over the entire study time span, as the required unit commitment schedule can be achieved by searching for the shortest path in the network. In order to find the global optimal solution for the economic dispatch problem within personal computer resources, a piecewise linear model is used for thermal units. Furthermore, linear programming is used in optimizing the benefits of ramping the units with low operating cost against the cost of shortening the service life of the turbine rotor. In this regard, linear programming is used to dispatch the power generation along committed units by considering a ramping penalty for the fatigue effect in rotor shafts, while preserving the operational constraints of the system as well as the generating units.

  5. Effects of incorporation of organically modified montmorillonite on the reaction mechanism of epoxy/amine cure.

    PubMed

    Alzina, Camille; Mija, Alice; Vincent, Luc; Sbirrazzuoli, Nicolas

    2012-05-17

    The aim of this study is to understand the effect of nonmodified or different organically modified montmorillonites on the reaction mechanism of epoxy/amine cure. The reference material consists of diglycidyl ether of bisphenol A (DGEBA) and 1,3-phenylene diamine (mPDA) in stoichiometric proportions. The reaction with various organically modified montmorillonites (I28E, I34TCN, and MMTm) is compared to highlight the catalytic effect of MMT water content and of the alkylammonium cations on the epoxy/amine reaction mechanism. In the absence of mPDA curing agent, DGEBA develops homopolymerization reactions with I28E, I34TCN, and MMTm. Chemorheological kinetics and advanced isoconversional analysis of epoxy cure are studied by rheometrical measurements and differential scanning calorimetry (DSC). Molecular mobility of the system under curing is modified in the presence of montmorillonites. Finally, the study underlines the role of montmorillonites and the influence of the change in reaction mechanisms on glass transition of the nanocomposites. PMID:22540520

  6. Physicochemical phenomena of electro-kinetic extraction of inorganic contaminants from kaolinite 

    E-print Network

    Scott, Travis Brooks

    1994-01-01

    Helmholtz ? Smoluchowski Model for Electro-osmosis Figure III. I Section of Consolidation Apparatus Figure III. 2 Section of Electrokinetic Cell Figure III. 3 Schematic of Electrokinetic Soil Testing Apparatus Figure III. 4 Schematic of Fluid and Gas... and correct laboratory format. Several samples contaminated with a single, uniform contaminant were prepared at one of the two different contaminant concentrations. Each sample was placed under a voltage gradient, allowing electro-osmosis and ionic...

  7. Characterization of electrokinetic mobility of microparticles in order to improve dielectrophoretic concentration

    Microsoft Academic Search

    José I. Martínez-López; Héctor Moncada-Hernández; Javier L. Baylon-Cardiel; Sergio O. Martínez-Chapa; Marco Rito-Palomares; Blanca H. Lapizco-Encinas

    2009-01-01

    Insulator-based dielectrophoresis (iDEP), an efficient technique with great potential for miniaturization, has been successfully\\u000a applied for the manipulation of a wide variety of bioparticles. When iDEP is applied employing direct current (DC) electric\\u000a fields, other electrokinetic transport mechanisms are present: electrophoresis and electroosmotic flow. In order to concentrate\\u000a particles, iDEP has to overcome electrokinetics. This study presents the characterization of

  8. Incorporating Cache Management Behavior into Seed Dispersal: The Effect of Pericarp Removal on Acorn Germination

    PubMed Central

    Yi, Xianfeng; Zhang, Mingming; Bartlow, Andrew W.; Dong, Zhong

    2014-01-01

    Selecting seeds for long-term storage is a key factor for food hoarding animals. Siberian chipmunks (Tamias sibiricus) remove the pericarp and scatter hoard sound acorns of Quercus mongolica over those that are insect-infested to maximize returns from caches. We have no knowledge of whether these chipmunks remove the pericarp from acorns of other species of oaks and if this behavior benefits seedling establishment. In this study, we tested whether Siberian chipmunks engage in this behavior with acorns of three other Chinese oak species, Q. variabilis, Q. aliena and Q. serrata var. brevipetiolata, and how the dispersal and germination of these acorns are affected. Our results show that when chipmunks were provided with sound and infested acorns of Quercus variabilis, Q. aliena and Q. serrata var. brevipetiolata, the two types were equally harvested and dispersed. This preference suggests that Siberian chipmunks are incapable of distinguishing between sound and insect-infested acorns. However, Siberian chipmunks removed the pericarp from acorns of these three oak species prior to dispersing and caching them. Consequently, significantly more sound acorns were scatter hoarded and more infested acorns were immediately consumed. Additionally, indoor germination experiments showed that pericarp removal by chipmunks promoted acorn germination while artificial removal showed no significant effect. Our results show that pericarp removal allows Siberian chipmunks to effectively discriminate against insect-infested acorns and may represent an adaptive behavior for cache management. Because of the germination patterns of pericarp-removed acorns, we argue that the foraging behavior of Siberian chipmunks could have potential impacts on the dispersal and germination of acorns from various oak species. PMID:24647670

  9. The effects of iron oxide incorporation on the chondrogenic potential of three human cell types

    PubMed Central

    Saha, Sushmita; Yang, Xuebin B; Tanner, Steven; Curran, Stephen; Wood, David; Kirkham, Jennifer

    2013-01-01

    Non-invasive monitoring of living cells in vivo provides an important tool in the development of cell-based therapies in cartilage tissue engineering. High-resolution magnetic resonance imaging (MRI) has been used to monitor target cell populations in vivo. However, the side-effects on cell function of the labelling reagents, such as superparamagnetic iron oxide (SPIO), are still unclear. This study investigated the effect of SPIO particles on the chondrogenic differentiation of human bone marrow stromal cells (HBMSCs), neonatal and adult chondrocytes in vitro. Cells were labelled with SPIO for 24 h and chondrogenesis induced in serum-free medium including TGF?3. For labelled/unlabelled cells, viability, morphology and proliferation were determined using CellTracker™ Green and PicoGreen dsDNA assays. The expression of SOX9, COL2A1 and ACAN was investigated using qRT–PCR after 2, 7 and 14 days. The results showed that viability was unaffected in all of the cells but cell morphology changed towards a 'stretched' phenotype following SPIO uptake. Cell proliferation was reduced only for labelled neonatal chondrocytes. SOX9 and COL2A1 expression decreased at day 2 but not at days 7 and 14 for labelled HBMSCs and adult chondrocytes; ACAN expression was unaffected. In contrast, SOX9 and COL2A1 expression were unaffected in labelled neonatal chondrocytes but a decrease in ACAN expression was seen at day 14. The results suggest that downregulation of chondrogenic genes associated with SPIO labelling is temporary and target cell-dependent. Resovist® can be used to label HBMSCs or mature chondrocytes for MR imaging of cells for cartilage tissue engineering. Copyright © 2012 John Wiley & Sons, Ltd. PMID:22396122

  10. Effect of chitosan film incorporated with tea polyphenol on quality and shelf life of pork meat patties.

    PubMed

    Qin, Yu-Yue; Yang, Ji-Yi; Lu, Hong-Bo; Wang, Sha-Sha; Yang, Jing; Yang, Xing-Chao; Chai, Man; Li, Lin; Cao, Jian-Xin

    2013-10-01

    The objective of this study was to investigate the effect of chitosan (CH) film incorporated with tea polyphenol (TP) on quality and shelf life of pork meat patties stored at 4±1 °C for 12 days. The microbiological, physicochemical (pH, thiobarbituric acid-reactive substances (TBARS) values, and metmyoglobin (MetMb)), and sensory qualities were measured on all the samples. A microbiological shelf-life extension of 6 days was achieved for CH and CH-TP treatment groups when compared to the control group. Wrapping with CH-TP composite film tended to retard the increases in TBARS values and MetMb content. CH-TP composite film maintained acceptable sensory quality of pork meat patties throughout the storage. The results indicated that CH-TP composite film could be a promising material as a packaging film for extending the shelf life of pork meat patties. PMID:23916647

  11. Effectiveness of phototherapy incorporated into an exercise program for osteoarthritis of the knee: study protocol for a randomized controlled trial

    PubMed Central

    2014-01-01

    Background Osteoarthritis is a chronic disease with a multifactor etiology involving changes in bone alignment, cartilage, and other structures necessary to joint stability. There is a need to investigate therapeutic resources that combine different wavelengths as well as different light sources (low-level laser therapy and light-emitting diode therapy) in the same apparatus for the treatment of osteoarthritis. The aim of the proposed study is to analyze the effect of the incorporation of phototherapy into a therapeutic exercise program for individuals with osteoarthritis of the knee. Methods/Design A double-blind, controlled, randomized clinical trial will be conducted involving patients with osteoarthritis of the knee. Evaluations will be performed using functional questionnaires before and after the treatment protocols, in a reserved room with only the evaluator and participant present, and no time constraints placed on the answers or evaluations. The following functional tests will also be performed: stabilometry (balance assessment), dynamometry (muscle strength of gluteus medius and quadriceps), algometry (pain threshold), fleximeter (range of motion), timed up-and-go test (functional mobility), and the functional reach test. The participants will then be allocated to three groups through a randomization process using opaque envelopes: exercise program, exercise program?+?phototherapy, or exercise program?+?placebo phototherapy, all of which will last for eight weeks. Discussion The purpose of this randomized clinical trial is to analyze the effect of the incorporation of phototherapy into a therapeutic exercise program for osteoarthritis of the knee. The study will support the practice based on evidence to the use of phototherapy in individuals with a diagnosis of osteoarthritis of the knee. Data will be published after the study is completed. Trial registration The protocol for this study has been submitted to Clinical Trials, registration number NCT02102347, on 29 March 2014. PMID:24919587

  12. Incorporation of Mean Stress Effects into the Micromechanical Analysis of the High Strain Rate Response of Polymer Matrix Composites

    NASA Technical Reports Server (NTRS)

    Goldberg, Robert K.; Roberts, Gary D.; Gilat, Amos

    2002-01-01

    The results presented here are part of an ongoing research program, to develop strain rate dependent deformation and failure models for the analysis of polymer matrix composites subject to high strain rate impact loads. A micromechanics approach is employed in this work, in which state variable constitutive equations originally developed for metals have been modified to model the deformation of the polymer matrix, and a strength of materials based micromechanics method is used to predict the effective response of the composite. In the analysis of the inelastic deformation of the polymer matrix, the definitions of the effective stress and effective inelastic strain have been modified in order to account for the effect of hydrostatic stresses, which are significant in polymers. Two representative polymers, a toughened epoxy and a brittle epoxy, are characterized through the use of data from tensile and shear tests across a variety of strain rates. Results computed by using the developed constitutive equations correlate well with data generated via experiments. The procedure used to incorporate the constitutive equations within a micromechanics method is presented, and sample calculations of the deformation response of a composite for various fiber orientations and strain rates are discussed.

  13. Effect of testosterone incorporation on cell proliferation and differentiation for polymer-bioceramic composites.

    PubMed

    da Costa, Kelen Jorge Rodrigues; Passos, Joel J; Gomes, Alinne D M; Sinisterra, Rubén D; Lanza, Célia R M; Cortés, Maria Esperanza

    2012-11-01

    In the current study, we characterized the polycaprolactone (PCL), poly(lactic acid-co-glycolic acid) (PLGA), and biphasic calcium phosphate (BCP) composites coated with testosterone propionate (T) using Fourier transform infrared spectroscopy (FTIR) and powder X-ray diffraction (XRD). Osteoblastic cells were seeded with PCL/BCP, PCL/BCP/T, PLGA/PCL/BCP and PLGA/PCL/BCP/T scaffolds, and cell viability, proliferation, differentiation and adhesion were analyzed. The results of physic-chemical experiments showed no displacements or suppression of bands in the FTIR spectra of scaffolds. The XRD patterns of the scaffolds showed an amorphous profile. The osteoblastic cells viability and proliferation increased in the presence of composites with testosterone over 72 h, and were significantly greater when PLGA/PCL/BCP/T scaffold was tested against PCL/BCP/T. Furthermore alkaline phosphatase production was significantly greater in the same group. In conclusion, the PLGA/PCL/BCP scaffold with testosterone could be a promising option for bone tissue applications due to its biocompatibility and its stimulatory effect on cell proliferation. PMID:22886580

  14. Incorporating cumulative effects into environmental assessments of mariculture: Limitations and failures of current siting methods

    SciTech Connect

    King, Sarah C. [Greenpeace Canada, 1726 Commercial Drive, Vancouver, B.C., V5N 4A3 (Canada)], E-mail: scoldwellking@hotmail.com; Pushchak, Ronald [School of Urban and Regional Planning, Ryerson University, 350 Victoria Street, Toronto, Ontario, M5B 2K3 (Canada)], E-mail: pushchak@ryerson.ca

    2008-11-15

    Assessing and evaluating the cumulative impacts of multiple marine aquaculture facilities has proved difficult in environmental assessment. A retrospective review of 23 existing mariculture farms in southwestern New Brunswick was conducted to determine whether cumulative interactions would have justified site approvals. Based on current scientific evidence of cumulative effects, six new criteria were added to a set of far-field impacts and other existing criteria were expanded to include regional and cumulative environmental impacts in Hargrave's [Hargrave BT. A traffic light decision system for marine finfish aquaculture siting. Ocean Coast Manag 2002; 45:215-35.] Traffic Light Decision Support System (DSS) presently used in Canadian aquaculture environmental assessments. Before mitigation, 19 of the 23 sites failed the amended set of criteria and after considering mitigation, 8 sites failed. Site and ecosystem indices yielded varying site acceptability scores; however, many sites would not have been approved if siting decisions had been made within a regional management framework and cumulative impact criteria were considered in the site evaluation process.

  15. Micellar electrokinetic chromatographic determination of rosuvastatin in rabbit plasma and evaluation of its pharmacokinetics and interaction with niacin.

    PubMed

    El-Kommos, Michael E; Mohamed, Niveen A; Ali, Hassan R H; Abdel Hakiem, Ahmed F

    2014-12-01

    A specific, accurate, precise and reproducible micellar electrokinetic chromatographic method was developed for in vitro and in vivo estimation of rosuvastatin, a synthetic and potent HMG-CoA inhibitor, in rabbit plasma. Further, its pharmacokinetics in the presence of niacin, which could be co-administered for monitoring of severe hypercholestremia, was investigated. The assay procedures involved simple liquid-liquid extraction of rosuvastatin and internal standard, atorvastatin, from a small plasma volume directly into acetonitrile. The organic layer was separated and evaporated under a gentle stream of nitrogen. The residue was reconstituted in the mobile phase and injected electrokinetically into electropherosis system. The background electrolyte consisted of borate buffer (25.0?mm, pH?9.5), 10.0% organic modifier (5.0% methanol?+?5.0% acetonitrile) and 25.0?mm sodium dodecyl sulfate at 20.0?kV applied voltage and 215.0?nm detection wavelength for the effective separation of rosuvastatin, niacin and atorvastatin. PMID:24828212

  16. Evaluation of a dual-cyclodextrin phase variant of capillary electrokinetic chromatography for separations of nonionizable solutes

    SciTech Connect

    Sepaniak, M.J.; Copper, C.L.; Whitaker, K.W.; Anigbogu, V.C. [Univ. of Tennessee, Knoxville, TN (United States)

    1995-07-01

    A capillary electrokinetic chromatography technique is described that employs neutral cyclodextrins (CDs) as a primary phase, transported with electroosmotic flow, and charged CDs as an electrophoretically mediated secondary phase. Neutral, hydrophobic solutes are separated on the basis of their differential distribution between these CD phases. The technique resembles micellar electrokinetic capillary chromatography (MECC) with regard to instrumentation and the fundamental relationships for resolution and capacity factor, which are influenced by the existence of a finite elution window. Conversely, the CD technique offers unique and beneficial characteristics when compared to MECC. Efficiency, selectivity, and system retention are evaluated on the basis of separations of polyaromatic hydrocarbons (PAHs). Efficiency is comparable to that of MECC (> 10{sup 5} plates/m). The specificity associated with solute-CD inclusion complexation provides elution orders for PAHs that do not follow the hydrophobicity trends of MECC. Moreover, since the CD phases are largely noninteractive, complex CD systems can be used to enhance selectivity. Capacity factors can be altered in a convenient and predictable fashion simply by changing the CD phase ratio. The technique is rather robust with regard to the use of running buffers containing organic solvents; the effects or organic modifier and pH on system retention are demonstrated. 19 refs., 4 figs., 1 tab.

  17. Electrokinetic Flow and Dispersion in Capillary Electrophoresis

    NASA Astrophysics Data System (ADS)

    Ghosal, Sandip

    2006-01-01

    Electrophoretic separation of a mixture of chemical species is a fundamental technique of great usefulness in biology, health care, and forensics. In capillary electrophoresis (which has evolved from its predecessor, slab-gel electrophoresis), the sample migrates through a single microcapillary instead of through the network of pores in a gel. A fundamental design problem is to minimize dispersion in the separation direction. Molecular diffusion is inevitable and sets a theoretical limit on the best separation that can be achieved. But in practice, there are a number of effects arising out of the interplay between fluid flow, chemistry, thermal effects, and electric fields that result in enhanced dispersion. This paper reviews the subject of fluid flow in such capillary microchannels and examines the various causes of enhanced dispersion that limit the efficiency of separation.

  18. Electrokinetic In Situ Treatment of Metal-Contaminated Soil

    NASA Technical Reports Server (NTRS)

    Quinn, Jacqueline; Clausen, Christian A., III; Geiger, Cherie; Reinhart, Debra

    2004-01-01

    An electrokinetic technique has been developed as a means of in situ remediation of soils, sludges, and sediments that are contaminated with heavy metals. Examples of common metal contaminants that can be removed by this technique include cadmium, chromium, zinc, lead, mercury, and radionuclides. Some organic contaminants can also be removed by this technique. In the electrokinetic technique, a low-intensity direct current is applied between electrodes that have been implanted in the ground on each side of a contaminated soil mass. The electric current causes electro-osmosis and migration of ions, thereby moving aqueous-phase subsurface contaminants from one electrode to the other. The half reaction at the anode yields H+, thereby generating an acid front that travels from the anode toward the cathode. As this acid front passes through a given location, the local increase in acidity increases the solubility of cations that were previously adsorbed on soil particles. Ions are transported towards one electrode or the other which one depending on their respective electric charges. Upon arrival at the electrodes, the ionic contaminants can be allowed to become deposited on the electrodes or can be extracted to a recovery system. Surfactants and other reagents can be introduced at the electrodes to enhance rates of removal of contaminants. Placements of electrodes and concentrations and rates of pumping of reagents can be adjusted to maximize efficiency. The basic concept of electrokinetic treatment of soil is not new. What is new here are some of the details of application and the utilization of this technique as an alternative to other techniques (e.g., flushing or bioremediation) that are not suitable for treating soils of low hydraulic conductivity. Another novel aspect is the use of this technique as a less expensive alternative to excavation: The cost advantage over excavation is especially large in settings in which contaminated soil lies near and/or under industrial buildings and therefore excavation would be made even more expensive by the need to prevent damage to numerous underground pipes and cables.

  19. Effect of phosphorus incorporation on morphology and optical properties of ZnO nanorods

    SciTech Connect

    Fan, Donghua, E-mail: donghua_fan@126.com [School of Applied Physics and Materials, Wuyi University, Jiangmen 529020 (China)] [School of Applied Physics and Materials, Wuyi University, Jiangmen 529020 (China); Zhang, Rong [Department of Physics, Shanghai Maritime University, 1550 Pudong Avenue, Shanghai 200135 (China)] [Department of Physics, Shanghai Maritime University, 1550 Pudong Avenue, Shanghai 200135 (China); Wang, Xianghu [Shanghai Dianji University, Shanghai 200240 (China)] [Shanghai Dianji University, Shanghai 200240 (China)

    2011-04-15

    Graphical abstract: XPS spectra of the P-doped ZnO nanorods: (a) Zn 2p, (b) O 1s, and (c) P 2p spectra. The red curve in c is the Gauss-fitting curve. (d) Raman spectra of P-doped (curve 1) and pure (curve 2) ZnO nanorods. Research highlights: {yields} P-doped ZnO nanorods have been prepared on Si substrates without any catalyst. {yields} The introduction of phosphorus leads to the growth of tapered tip in the nanorods. {yields} The formation of tapered tip is attributed to the relaxation of the lattice strain along the radial direction. {yields} The strong ultraviolet peak is connected with the phosphorus acceptor-related emissions. -- Abstract: Phosphorus-doped ZnO nanorods have been prepared on Si substrates by thermal evaporation process without any catalyst. X-ray photoelectron spectroscopy and Raman spectra indicate that phosphorus entering into ZnO nanorods mainly occupies Zn site rather than O one. The introduction of phosphorus leads to the morphological changes of nanorods from hexagonal tip to tapered one, which should be attributed to the relaxation of the lattice strain caused by phosphorus occupying Zn site along the radial direction. Transmission electron microscopy shows that phosphorus-doped ZnO nanorods still are single crystal and grow along [0 0 0 1] direction. The effect of phosphorous dopant on optical properties of ZnO nanorods also is studied by the temperature-dependent photoluminescence spectra, which indicates that the strong ultraviolet emission is connected with the phosphorus acceptor-related emissions.

  20. G5-PEG PAMAM dendrimer incorporating nanostructured lipid carriers enhance oral bioavailability and plasma lipid-lowering effect of probucol.

    PubMed

    Qi, Rong; Li, Yan-Zhi; Chen, Cong; Cao, Yi-Ni; Yu, Mao-Mao; Xu, Lu; He, Bing; Jie, Xu; Shen, Wen-Wen; Wang, Yu-Nan; van Dongen, Mallory A; Liu, Guo-Qing; Banaszak Holl, Mark M; Zhang, Qiang; Ke, Xue

    2015-07-28

    This work aimed to improve the oral bioavailability and plasma lipid-lowering effect of probucol (PB) by constructing a combined drug delivery system (CDDS) composed of nanostructured lipid carrier (NLC) and PEGylated poly(amidoamine) dendrimer (PEG-PAMAM). PEG-PAMAM with dendrimer generations of 5 (G5-PEG) or 7 (G7-PEG) were incorporated in PB-NLCs to form PB-CDDSs, PB-NLCs/G5-PEG and PB-NLCs/G7-PEG. The resultant two kinds of PB-CDDSs were characterized by particle size, zeta potential, drug encapsulation efficacy, PB release rates, and physical stability. Formulation effects of NLC and CDDS on the cellular uptake of hydrophobic drug were explored in Caco-2 cells by fluorescent Cy5 dye as a hydrophobic drug model. Furthermore, in vivo pharmacokinetics of the PB-CDDS composed of G5-PEG and PB-NLCs were investigated in a low density lipoprotein receptor knockout (LDLr-/-) mouse model, including plateau plasma PB concentrations after oral administration of multiple doses, and bioavailability after oral administration of a single dose of different PB formulations. In addition, lipid-lowering effect of PB-NLCs/G5-PEG was studied. The results indicate that both G5-PEG and G7-PEG significantly improved aqueous solubility of PB. The two PB-CDDSs exhibited similar particle size (around 150nm) as PB-NLCs, but slower PB burst release rate, higher total PB release amount, and better particle morphology and storage stability than PB-NLCs. In comparison with traditional NLC, CDDS dramatically enhanced cellular uptake of Cy5 into Caco-2 cells. In vivo results demonstrate that PB-NLCs/G5-PEG had the highest plateau plasma PB concentration and oral bioavailability, and the greatest cholesterol-lowering effect in comparison with PB suspensions and PB-NLCs. Therefore, G5-PEG incorporating NLC can be exploited as a promising drug delivery system to improve oral bioavailability and lipid-lowering effect of PB. PMID:26003044

  1. Effect of intentional Na-incorporation on the structural, optical and electrical properties of CuInS 2:Na thin films for solar energy conversion

    Microsoft Academic Search

    Morched Zribi; Mounir Kanzari

    2011-01-01

    Na-doped CuInS2 material is obtained by the incorporation of the sodium of an atomic percentage in amounts of 0, 0.1, 0.5, 1, 2 and 3% with a stoechiometric mixture of the elements copper, indium and sulfur taken in the stoechiometric proportions. We have investigated in this work the effect of intentional Na-incorporation on the structural, optical and electrical properties of

  2. Effects of omega-3 fatty acids on vascular smooth muscle cells: Reduction in arachidonic acid incorporation into inositol phospholipids

    Microsoft Academic Search

    Nagender R. Yerram; Arthur A. Spector

    1989-01-01

    A rapid increase in arachidonic acid incorporation into phosphatidylinositol (PI) occurred following exposure of cultured\\u000a porcine pulmonary artery smooth muscle cells to calcium ionophore A23187. This response was specific for PI and phosphatidic\\u000a acid; none of the other phosphoglycerides showed any increase in arachidonic acid incorporation. The incorporation of [3H]inositol also was increased, indicating that complete synthesis of PI rather

  3. Studies on the effect of pilocarpine incorporation into a submicron emulsion on the stability of the drug and the vehicle.

    PubMed

    Zurowska-Pryczkowska, K; Sznitowska, M; Janicki, S

    1999-05-01

    In order to obtain a novel ocular formulation with a potential for prolonging pilocarpine activity, the drug (2.0%) was incorporated into a submicron emulsion containing soya-bean oil and lecithin as emulgator. The effect of drug incorporation into the emulsion on its physical stability and on the other hand, the potential of the vehicle to reduce drug degradation at pH higher than 5.0 was studied. The pH was adjusted to 6.5 or 5.0 and the physicochemical stability of the formulations was observed. The mean diameter of oily particles in the resulting emulsions measured by a laser diffractometer was 0.6-0.7 micron and this was larger than in a drug-free emulsion where a 0.33 micron value was measured. The formulations were physically stable for 6 months at 4 degrees C, but progressing chemical degradation of pilocarpine was noted at pH 6.5. At that pH nearly 8% of pilocarpine was degraded to isopilocarpine and pilocarpic acid, both in the emulsion and in the solution. Thus, it may be concluded that pilocarpine in submicron emulsion is not protected against degradation. The presence of pilocarpine changes the physical stability of the vehicle since the formulation was easily destabilized during autoclaving or at room temperature. In the presence of higher concentration of lecithin (2.4%) or co-emulgators (poloxamer 2.0% or Tween 80 0.5%) the mean droplet size in the emulsions was the same as in a drug-free system. However the emulsions containing poloxamer were not stable during storage. Viscosity of pilocarpine emulsions can be increased by addition of methylcellulose or sodium carmellose (1.0%), but an intensive creaming occurs in these systems. Pilocarpine base is less suitable for emulsion preparation than hydrochloride salt, and emulsions prepared at pH 5.0 show the most satisfying stability. PMID:10382109

  4. Mechanistic studies of partial-filing micellar electrokinetic chromatography

    SciTech Connect

    Nelson, W.M.; Lee, C.S. [Ames National Lab., IA (United States)] [Ames National Lab., IA (United States); [Iowa State Univ., Ames, IA (United States)

    1996-09-15

    The need for coupling micellar electrokinetic chromatography (MEKC) with electrospray mass spectrometry initiates the development of partial-filling MEKC. In comparison with conventional MEKC, only a small portion of the capillary is filled with a micellar solution for performing the separation in partial-filling MEKC. Analytes first migrate into the micellar plug, where the separation occurs, and then into the leading electrophoresis buffer, which is free of surfactants. A theoretical model is proposed for predicting the separation behavior of triazine herbicides in partial-filling MEKC. The comparisons between conventional and partial-filling MEKC in terms of separation efficiency and resolution of triazine herbicides are presented and discussed. The optimization techniques, possible applications, and advantages of partial-filling MEKC are similarly addressed. 11 refs., 6 figs., 5 tabs.

  5. Electrokinetic treatment of firing ranges containing tungsten-contaminated soils.

    PubMed

    Braida, Washington; Christodoulatos, Christos; Ogundipe, Adebayo; Dermatas, Dimitris; O'Connor, Gregory

    2007-11-19

    Tungsten-based alloys and composites are being used and new formulations are being considered for use in the manufacturing of different types of ammunition. The use of tungsten heavy alloys (WHA) in new munitions systems and tungsten composites in small caliber ammunition could potentially release substantial amounts of this element into the environment. Although tungsten is widely used in industrial and military applications, tungsten's potential environmental and health impacts have not been thoroughly addressed. This necessitates the research and development of remedial technologies to contain and/or remove tungsten from soils that may serve as a source for water contamination. The current work investigates the feasibility of using electrokinetics for the remediation of tungsten-contaminated soils in the presence of other heavy metals of concern such as Cu and Pb with aim to removing W from the soil while stabilizing in situ, Pb and Cu. PMID:17686582

  6. Micellar electrokinetic chromatography of scopolamine-related anticholinergics.

    PubMed

    Wu, H L; Huang, C H; Chen, S H; Wu, S M

    1998-04-01

    A simple micellar electrokinetic chromatography (MEKC) method is described for the separation of scopolamine N-oxide hydrobromide (SO), scopolamine hydrobromide (SH), scopolamine N-methylbromide (SM) and scopolamine N-butylbromide (SB), and for the quantitation of SH, SM and SB (using SO as an internal standard). The analysis of these drugs was performed in a phosphate buffer (30 mM; pH 7.00) with sodium dodecyl sulfate (SDS) (30 mM) as an anionic surfactant. Several parameters affecting the separation of the drugs were studied, including the concentrations of the buffer and SDS. The stability of the drugs in the phosphate buffer (pH 7.00) was also examined. Partial application of the method to the determination of scopolamine N-butylbromide in tablets proved to be feasible. PMID:9588013

  7. Entropic Electrokinetics: Recirculation, Particle Separation, and Negative Mobility

    NASA Astrophysics Data System (ADS)

    Malgaretti, Paolo; Pagonabarraga, Ignacio; Rubi, J. Miguel

    2014-09-01

    We show that when particles are suspended in an electrolyte confined between corrugated charged surfaces, electrokinetic flows lead to a new set of phenomena such as particle separation, mixing for low-Reynolds micro- and nanometric devices, and negative mobility. Our analysis shows that such phenomena arise, for incompressible fluids, due to the interplay between the electrostatic double layer and the corrugated geometrical confinement and that they are magnified when the width of the channel is comparable to the Debye length. Our characterization allows us to understand the physical origin of such phenomena, therefore, shedding light on their possible relevance in a wide variety of situations ranging from nano- and microfluidic devices to biological systems.

  8. Electrokinetic Characteristics of Calcined Kaolinite in Aqueous Electrolytic Solutions

    NASA Astrophysics Data System (ADS)

    Chen, Tianxing; Zhao, Yunliang; Li, Hongliang; Liu, Jia; Song, Shaoxian

    2015-03-01

    In this work, the electrokinetic characteristics of calcined kaolinite in aqueous solutions has been studied in the presence of the electrolytes of NaCl, KCl, NH4Cl, NaNO3, MgCl2, CaCl2 and AlCl3, through electrophoretic measurement. The experimental results have shown that the zeta potential was closely dependent on the valence and concentration of the electrolytic cations, but not on the type of the cations. The higher the valence and the concentration were, the stronger the impact to the zeta potential was. Al3+ could reverse the potential sign from negative to positive. In addition, it was found that the monovalent anions of Cl- and NO3- made a big difference to the zeta potential at the same dosage.

  9. Multiplexed electrokinetic sample fractionation, preconcentration and elution for proteomics.

    PubMed

    Hua, Yujuan; Jemere, Abebaw B; Dragoljic, Jelena; Harrison, D Jed

    2013-07-01

    Both 6 and 8-channel integrated microfluidic sample pretreatment devices capable of performing "in space" sample fractionation, collection, preconcentration and elution of captured analytes via sheath flow assisted electrokinetic pumping are described. Coatings and monolithic polymer beds were developed for the glass devices to provide cationic surface charge and anodal electroosmotic flow for delivery to an electrospray emitter tip. A mixed cationic ([2-(methacryloyloxy)ethyl] trimethylammonium chloride) (META) and hydrophobic butyl methacrylate-based monolithic porous polymer, photopolymerized in the 6- or 8-fractionation channels, was used to capture and preconcentrate samples. A 0.45 wt% META loaded bed generated comparable anodic electroosmotic flow to the cationic polymer PolyE-323 coated channel segments in the device. The balanced electroosmotic flow allowed stable electrokinetic sheath flow to prevent cross contamination of separated protein fractions, while reducing protein/peptide adsorption on the channel walls. Sequential elution of analytes trapped in the SPE beds revealed that the monolithic columns could be efficiently used to provide sheath flow during elution of analytes, as demonstrated for neutral carboxy SNARF (residual signal, 0.08% RSD, n = 40) and charged fluorescein (residual signal, 2.5% n = 40). Elution from monolithic columns showed reproducible performance with peak area reproducibility of ~8% (n = 6 columns) in a single sequential elution and the run-to-run reproducibility was 2.4-6.7% RSD (n = 4) for elution from the same bed. The demonstrated ability of this device design and operation to elute from multiple fractionation beds into a single exit channel for sample analysis by fluorescence or electrospray mass spectrometry is a crucial component of an integrated fractionation and assay system for proteomics. PMID:23712291

  10. Effect of incorporation of Brassica napus L. residues in soils on mycorrhizal fungus colonisation of roots and phosphorus uptake by maize ( Zea mays L.)

    Microsoft Academic Search

    Sylvain Pellerin; Alain Mollier; Christian Morel; Christian Plenchette

    2007-01-01

    Plants in the Brassicaceae family are known to contain thioglucoside compounds that produce isothiocyanates when tissues are disrupted. These chemicals have a negative effect on soil-borne fungal pathogens, and possibly on vesicular–arbuscular mycorrhizal (AM) fungi. We investigated the effect of incorporation of Brassica napus L. residues in a soil on mycorrhizal colonisation of roots, P uptake and growth of following

  11. Probing Into The Learning Effectiveness of Situated Learning Incorporated into a Specific Web-Assisted Instruction in Nutritional Chemistry Taken by Learners with Learning-Style Differences

    Microsoft Academic Search

    Zang-Yuan Own; Ding-Uei Chen

    In this study, the effect of situated learning theory, incorporated into a specific web-assisted instructional environment in nutritional chemistry, on learning achievements and learning satisfactions of randomly selected college students was investigated, and under such a method of instruction, its effect on learning achievements by learners with different learning styles was analyzed in depth. The study results showed: 1. The

  12. The effect of ethanol and/or acetaldehyde on the incorporation of U/sup 14/C-glucose into human umbilical artery lipids

    SciTech Connect

    Dupont, J.; Nelson, A.W.; Clow, D.J.

    1982-01-01

    The effect of ethanol, acetaldehyde and a combination of ethanol and acetaldehyde added in vitro was determined on their abilities to alter conversion of glucose to lipid. When human umbilical arteries were perfused with acetaldehyde at a 0.5% concentration, a significant reduction (p less than 0.05) of /sup 14/C incorporation into lipid was observed. This reduction was found to be the result of depressed incorporation of glucose into phospholipid (PL) and triacylglycerides (TG). Acetaldehyde at a concentration of 0.25% appeared to depress incorporation; however, this was not significant. Acetaldehyde plus ethanol at final equal concentrations of 0.25%, 0.5% and 1.0% had no effect on incorporation of U/sup 14/ C-glucose into lipid. Ethanol at concentrations of 0.5%, 0.25% and 0.125% had no effect on the incorporation of U/sup 14/ C-glucose into lipid. The study suggests that acetaldehyde can depress the conversion of glucose into umbilical artery lipids. However, acetaldehyde in the presence of equal concentrations of ethanol does not exhibit this ability to depress conversion of glucose to lipids suggesting some cellular counter effect of these two agents.

  13. Hydrodynamics and electrokinetics of spherical liposomes with coatings of terminally anchored poly(ethylene glycol): Numerically exact electrokinetics with self-consistent mean-field polymer

    Microsoft Academic Search

    Reghan J. Hill

    2004-01-01

    A detailed theoretical model is presented to interpret electrokinetic experiments performed on colloids with uncharged polymer layers. The methodology removes many of the degrees of freedom that otherwise have to be accounted for by adopting multiple empirical fitting parameters. Furthermore, the level of detail provides a firm basis for future studies examining liposome surface chemistry and charge, surface-charge mobility, and

  14. Incorporation of chitosan in acrylic bone cement: effect on antibiotic release, bacterial biofilm formation and mechanical properties.

    PubMed

    Tunney, M M; Brady, A J; Buchanan, F; Newe, C; Dunne, N J

    2008-04-01

    Bacterial infection remains a significant problem following total joint replacement. Efforts to prevent recurrent implant infection, including the use of antibiotic-loaded bone cement for implant fixation at the time of revision surgery, are not always successful. In this in vitro study, we investigated whether the addition of chitosan to gentamicin-loaded Palacos R bone cement increased antibiotic release and prevented bacterial adherence and biofilm formation by Staphylococcus spp. clinical isolates. Furthermore, mechanical tests were performed as a function of time post-polymerisation in pseudo-physiological conditions. The addition of chitosan to gentamicin-loaded Palacos R bone cement significantly decreased gentamicin release and did not increase the efficacy of the bone cement at preventing bacterial colonisation and biofilm formation. Moreover, the mechanical performance of cement containing chitosan was significantly reduced after 28 days of saline degradation with the compressive and bending strengths not in compliance with the minimum requirements as stipulated by the ISO standard for PMMA bone cement. Therefore, incorporating chitosan into gentamicin-loaded Palacos R bone cement for use in revision surgery has no clinical antimicrobial benefit and the detrimental effect on mechanical properties could adversely affect the longevity of the prosthetic joint. PMID:18266082

  15. Effects of germanium incorporation on optical performances of silicon germanium passive devices for group-IV photonic integrated circuits

    NASA Astrophysics Data System (ADS)

    Cho, Seongjae; Park, Joonsuk; Kim, Hyungjin; Sinclair, Robert; Park, Byung-Gook; Harris, James S.

    2014-02-01

    Optical interconnect in integrated optoelectronic circuits is one of the promising next-generation technologies for replacing metalized interconnect. Efforts have been made to use silicon (Si)-compatible materials such as germanium (Ge) and Ge-buffered III-V compound semiconductors, along with Si, as optical sources for Si and group-IV integrated optoelectronic systems. This opens the possibility that higher fraction of Ge with its high refractive index (n) can be incorporated in Si waveguide for optical interconnect and the graftability between Si and group-IV or III-V materials would be improved in silicon photonics. In this work, advantageous features of nano-structured silicon germanium (Si1-xGex) optical waveguide with different Ge fraction (x) were evaluated by both optical simulations and theoretical calculations, which are mainly found in the enhanced optical confinement and better interfacing capability. Along with the SiGe waveguide, performance of Si1-xGex microring resonator under material loss in the effect of extinction coefficient (k) has been investigated to suggest the necessity of optimizing the Ge content in Si1-xGex passive devices. While carrying out the establish design criteria, n and k have been modelled in closed-form functions of Ge fraction at 1550 nm. Furthermore, by examining high-resolution transmission electron microscopy (HR-TEM) images, process compatibility of Ge with either group-IV alloys or III-V compound semiconductors is confirmed for the monolithically integrated photonic circuits.

  16. Effect of Sb incorporation on structure and magnetic properties of quaternary ferromagnetic semiconductor (Ga, Mn)(As, Sb) thin films

    SciTech Connect

    Deng, J. J.; Che, J. T.; Chen, J.; Wang, W. J.; Hu, B. [Mathematics and Physics Department, North China Electric Power University, Beijing 102206 (China)] [Mathematics and Physics Department, North China Electric Power University, Beijing 102206 (China); Wang, H. L.; Zhao, J. H. [Institute of Semiconductors, State Key Laboratory of Superlattices and Microstructures, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083 (China)] [Institute of Semiconductors, State Key Laboratory of Superlattices and Microstructures, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083 (China)

    2013-12-28

    GaAs-based quaternary ferromagnetic semiconductor (Ga, Mn)(As, Sb) has been successfully prepared by molecular-beam epitaxy. High-resolution x-ray diffraction measurements indicate that the lattice constant has a notable alteration with changing Sb content. Magnetic measurements demonstrate the same evolution of the Curie temperature T{sub C} and the effective Mn content x{sub eff} with increasing Sb content. The incorporation of low Sb content is of benefit to increasing x{sub eff}, thus, increasing T{sub C}. However, higher Sb content degrades the crystal quality, resulting in a decrease of x{sub eff}. Experimental results show that T{sub C} is proportional to the product of x{sub eff} and p{sup 1/3}, which is consistent with the Zener Model. The exchange energy N{sub 0}? is calculated to be ?1.09 eV, which is similar to that of (Ga, Mn)As.

  17. Electrokinetic desalination using honeycomb carbon nanotubes (HC-CNTs): a conceptual study by molecular simulation.

    PubMed

    Chen, Qile; Kong, Xian; Li, Jipeng; Lu, Diannan; Liu, Zheng

    2014-09-21

    A new concept of electrokinetic desalination using a CNT honeycomb is presented through molecular dynamics simulation. The preferential translocation of ions towards the outlets near two electrodes was realized by applying an electric field perpendicular to bulk fluid flow in a CNT network, which, in the meantime, generated deionized water flux discharged from the central outlets. The effects of the major factors such as electric field strength, numbers of separation units, diameter of CNT, and ion concentration on the desalination were examined. It was shown that over 95% salt rejection and around 50% fresh water recovery were achieved by the presented module by applying an electric field of 0.8 V nm(-1). CNT diameter, which is critical to ion rejection without the electric field, had a marginal effect on the desalination of this new module when a strong electric field was applied. The desalination was also not sensitive to ion concentration, indicating its excellent workability for a wide range of water salinity, e.g. from brackish water to seawater. A potential of mean force profile revealed a free energy barrier as large as 2.0-6.0 kcal mol(-1) for ions to move opposite to the implemented electrical force. The simulation confirmed the high potential of the CNT honeycomb in water desalination. PMID:25092215

  18. Can neutral analytes be concentrated by transient isotachophoresis in micellar electrokinetic chromatography and how much?

    PubMed

    Matczuk, Magdalena; Foteeva, Lidia S; Jarosz, Maciej; Galanski, Markus; Keppler, Bernhard K; Hirokawa, Takeshi; Timerbaev, Andrei R

    2014-06-01

    Transient isotachophoresis (tITP) is a versatile sample preconcentration technique that uses ITP to focus electrically charged analytes at the initial stage of CE analysis. However, according to the ruling principle of tITP, uncharged analytes are beyond its capacity while being separated and detected by micellar electrokinetic chromatography (MEKC). On the other hand, when these are charged micelles that undergo the tITP focusing, one can anticipate the concentration effect, resulting from the formation of transient micellar stack at moving sample/background electrolyte (BGE) boundary, which increasingly accumulates the analytes. This work expands the enrichment potential of tITP for MEKC by demonstrating the quantitative analysis of uncharged metal-based drugs from highly saline samples and introducing to the BGE solution anionic surfactants and buffer (terminating) co-ions of different mobility and concentration to optimize performance. Metallodrugs of assorted lipophilicity were chosen so as to explore whether their varying affinity toward micelles plays the role. In addition to altering the sample and BGE composition, optimization of the detection capability was achieved due to fine-tuning operational variables such as sample volume, separation voltage and pressure, etc. The results of optimization trials shed light on the mechanism of micellar tITP and render effective determination of selected drugs in human urine, with practical limits of detection using conventional UV detector. PMID:24797392

  19. Enhanced-electrokinetic extraction of heavy metals from dredged harbor sediment.

    PubMed

    Yoo, Jong-Chan; Yang, Jung-Seok; Jeon, Eun-Ki; Baek, Kitae

    2015-07-01

    In this study, the feasibility of an ex situ electrokinetic (EK) process combined with pre-oxidation using hydrogen peroxide (H2O2) and pre-washing using ethylenediaminetetraacetic acid (EDTA) was investigated in enhancing the extraction of Cu, Pb, and Zn from actual dredged harbor sediment. H2O2 pre-oxidation led to a change in the fractionation of Cu bound to organic matter and the sulfide fraction in the Fe-Mn oxides to the exchangeable fraction, but was not effective at removing metals. In contrast, EDTA pre-washing changed the Fe-Mn oxide-bound fractions of Cu and Pb into easily extractable fractions; 20.1, 27.5, and 32.8 % of Cu, Pb, and Zn were removed, respectively. During EK treatment, metals were transported toward the anode by electromigration of negatively charged complexes such as metal-EDTA and metal-citrate. However, EK treatment did not significantly enhance the removal of metals because metals accumulated near the anodic region with an increase in the exchangeable fraction due to the short EK operating duration and low voltage gradient. Therefore, it is necessary to extend the EK operating duration and/or increase the voltage gradient for effective transportation and removal of metals from sediment. PMID:25655751

  20. Micro and nanoscale electrochemical systems for reagent generation, coupled electrokinetic transport and enhanced detection

    NASA Astrophysics Data System (ADS)

    Contento, Nicholas M.

    Chemical analysis is being performed in devices operated at ever decreasing length scales in order to harness the fundamental benefits of micro and nanoscale phenomena while minimizing operating footprint and sample size. The advantages of moving traditional sample or chemical processing steps (e.g. separation, detection, and reaction) into micro- and nanofluidic devices have been demonstrated, and they arise from the relatively rapid rates of heat and mass transport at small length scales. The use of electrochemical methods in micro/nanoscale systems to control and improve these processes holds great promise. Unfortunately, much is still not understood about the coupling of multiple electrode driven processes in a confined environment nor about the fundamental changes in device performance that occur as geometries approach the nanoscale regime. At the nanoscale a significant fraction of the sample volume is in close contact with the device surface, i.e. most of the sample is contained within electronic or diffusion layers associated with surface charge or surface reactions, respectively. The work presented in this thesis aims to understand some fundamental different behaviors observed in micro/nanofluidic structures, particularly those containing one or more embedded, metallic electrode structures. First, a quantitative method is devised to describe the impact of electric fields on electrochemistry in multi-electrode micro/nanofluidic systems. Next the chemical manipulation of small volumes (? 10-13 L) in micro/nanofluidic structures is explored by creating regions of high pH and high dissolved gas (H 2) concentration through the electrolysis of H2O. Massively parallel arrays of nanochannel electrodes, or embedded annular nanoband electrodes (EANEs), are then studied with a focus on achieving enhanced signals due to coupled electrokinetic and electrochemical effects. In EANE devices, electroosmotic flow results from the electric field generated between the closely spaced working and counter electrode, causing beneficial convective transport to the electrode surface. Finally, redox cycling of electroactive species at recessed ring-disk nanoelectrode arrays is described with a focus on the use of finite element calculations to predict electrode performance as a function of electrode geometry. The improved understanding of electrochemistry, electrokinetics and mass transport in micrometer and nanometer scale structures presented in this thesis should guide the development of next-generation devices for combinatorial processing involving electrochemical analysis, reagent generation and heterogeneous reaction.

  1. Effect of soy protein isolate incorporation on quality characteristics and shelf-life of buffalo meat emulsion sausage.

    PubMed

    Ahmad, S; Rizawi, J A; Srivastava, P K

    2010-06-01

    Incorporation of soy protein isolate (SPI) at 0, 15, and 25% levels in buffalo meat was investigated for production, quality and shelf life evaluation of emulsion sausage (ES). Quality of ES was evaluated by pH, moisture content, thiobarbituric acid (TBA) number, total plate count (TPC), and Yeast and mold count, sensory, characteristics and instrumental colour and texture measurements. It was found that pH and moisture content were slightly affected, TBA number remained unaffected. TPC of ES fresh sample was found in the range 3.7-4.3 log cfu/g. ES was acceptable to the panelists and incorporation of SPI did not affect the acceptability. SPI incorporation increased Hunter L and b values but decreased a value and instrumental hardness. During storage (0°C), L, a, b values fl uctuated irregularly. It was concluded that incorporation of SPI slightly improved texture, juiciness and colour of emulsion sausage. PMID:23572639

  2. Simulation-based design of a strained graphene field effect transistor incorporating the pseudo magnetic field effect

    SciTech Connect

    Souma, Satofumi, E-mail: ssouma@harbor.kobe-u.ac.jp; Ueyama, Masayuki; Ogawa, Matsuto [Department of Electrical and Electronic Engineering, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501 (Japan)

    2014-05-26

    We present a numerical study on the performance of strained graphene-based field-effect transistors. A local strain less than 10% is applied over a central channel region of the graphene to induce the shift of the Dirac point in the channel region along the transverse momentum direction. The left and the right unstrained graphene regions are doped to be either n-type or p-type. By using the atomistic tight-binding model and a Green's function method, we predict that the gate voltage applied to the central strained graphene region can switch the drain current on and off with an on/off ratio of more than six orders of magnitude at room temperature. This is in spite of the absence of a bandgap in the strained channel region. Steeper subthreshold slopes below 60?mV/decade are also predicted at room temperature because of a mechanism similar to the band-to-band tunneling field-effect transistors.

  3. Effect of iodide on glucose oxidation and /sup 32/P incorporation into phospholipids stimulated by different agents in dog thyroid slices

    SciTech Connect

    Tseng, F.Y.; Rani, C.S.; Field, J.B.

    1989-03-01

    Since iodide (I-) inhibits TSH stimulation of cAMP formation, which mediates most of the effects of the hormone, it has been assumed that this accounts for the inhibitory action of iodide on the thyroid. However, TSH stimulation of 32P incorporation into phospholipids and stimulation of thyroid metabolism by other agonists, such as carbachol, phorbol esters, and ionophore A23187, is not cAMP mediated. The present studies examined the effect of iodide on stimulation of glucose oxidation and 32P incorporation into phospholipids by TSH and other agonists to determine if the inhibition of cAMP formation was responsible for the action of iodide. Preincubation of dog thyroid slices for 1 h with iodide (10(-4) M) inhibited TSH-, (Bu)2cAMP-, carbachol-, methylene blue-, 12-O-tetradecanoyl phorbol-13-acetate-, ionophore A23187-, prostaglandin E1-, and cholera toxin-stimulated glucose oxidation. I- also inhibited the stimulation by TSH, 12-O-tetradecanoyl phorbol-13-acetate, carbachol, and ionophore A23187 of 32P incorporation into phospholipids. The inhibition was similar whether iodide was added 2 h before or simultaneously with the agonist. I- itself sometimes stimulated basal glucose oxidation, but had no effect on basal 32P incorporation into phospholipids. The effects of iodide on basal and agonist-stimulated thyroid metabolism were blocked by methimazole (10(-3) M). When dog thyroid slices were preloaded with 32PO4 or (1-14C)glucose, the iodide inhibition of agonist stimulation disappeared, suggesting that the effect of iodide involves the transport process. In conclusion, I- inhibited stimulation of glucose oxidation and 32P incorporation into phospholipids by all agonists, indicating that the effect is independent of the cAMP system and that iodide autoregulation does not only involve this system. Oxidation and organification of iodide are necessary for the inhibition.

  4. The effect of the method of incorporation of Trifolium resupinatum L. and Vicia villosa Roth. Residues in the Soil on the Performance of a Succeeding Cereal Crop

    Microsoft Academic Search

    R. T. Poutala; A. Hannukkala

    1995-01-01

    In this study, roots, shoots and whole crop stand of persian clover and hairy vetch grown as green fallow were incorporated in the soil either in a conventional manner (autumn ploughing) or following conservation tillage methods (stubble cultivation, minimum tillage). The after-effect on cereal crop performance was followed for two successive years. The impact on grain yield, grain characteristics and

  5. In vitro effect of liposome-incorporated valinomycin on growth and macromolecular synthesis of normal and ras -transformed 3T3 cells

    Microsoft Academic Search

    Sayed S. Daoud; R. L. Juliano

    1989-01-01

    Summary Valinomycin is a depsipeptide antibiotic that selectively translocates potassium ion across biologic membranes. This drug has been reported to display antitumor effects, but its use has been limited by its extreme toxicity. However, its incorporation into lipid vesicles (liposomes) has resulted in a reduction in toxicity and in the enhancement of the drug's therapeutic index [4]. As a preliminary

  6. The effects of incorporating a virtual agent in a computer-aided test designed for stress management education: The mediating role of enjoyment

    Microsoft Academic Search

    Seung-A. Annie Jin

    2010-01-01

    Drawing upon the Entertainment–Education paradigm, this study evaluated the effectiveness of a computer-aided interactive test designed for stress management education targeting college students. The presence (vs. absence) of a virtual agent incorporated into the interactive test was proposed as the key factor that induces enjoyment and educational outcomes. The interactive test consisted of scenarios describing stressful situations that could occur

  7. Simultaneous determination of eleven preservatives in cosmetics by micellar electrokinetic chromatography.

    PubMed

    Wang, Ping; Ding, Xiaojing; Li, Yun; Yang, Yuanyuan

    2012-01-01

    A new method for the simultaneous quantitation of 11 preservatives-imidazolidinyl urea, benzyl alcohol, dehydroacetic acid, sorbic acid, phenoxyethanol, benzoic acid, salicylic acid, and four parabens (methyl, ethyl, propyl, and butyl)-in cosmetics by micellar electrokinetic capillary chromatography was established and validated. The separation was performed using an uncoated fused-silica capillary (50 pm id x 60.2 cm, effective length 50 cm) with a running buffer consisting of 15 mmol/L sodium tetraborate, 60 mmol/L boric acid, and 100 mmol/L sodium dodecyl sulfate. A 1:10 dilution of the running buffer was used as the sample buffer to extract the cosmetic samples. The key factors, such as the concentration and pH of the running and sample buffers, which influence quantitative analysis of the above 11 preservatives in cosmetic samples, were investigated in detail. The linear ranges of the calibration curves for imidazolidinyl urea and the other 10 preservatives were 50-1000 and 10-200 mg/L, respectively. The correlation coefficients of the standard curves were all higher than 0.999. The recoveries at the concentrations studied ranged from 93.0 to 102.7%. RSDs were all less than 5%. The new method with simple sample pretreatment met the needs for routine analysis of the 11 preservatives in cosmetics. PMID:22970574

  8. Electrokinetic and hydrodynamic properties of charged-particles systems: From small electrolyte ions to large colloids

    E-print Network

    G. Nägele; M. Heinen; A. J. Banchio; C. Contreras-Aburto

    2013-09-13

    Dynamic processes in dispersions of charged spherical particles are of importance both in fundamental science, and in technical and bio-medical applications. There exists a large variety of charged-particles systems, ranging from nanometer-sized electrolyte ions to micron-sized charge-stabilized colloids. We review recent advances in theoretical methods for the calculation of linear transport coefficients in concentrated particulate systems, with the focus on hydrodynamic interactions and electrokinetic effects. Considered transport properties are the dispersion viscosity, self- and collective diffusion coefficients, sedimentation coefficients, and electrophoretic mobilities and conductivities of ionic particle species in an external electric field. Advances by our group are also discussed, including a novel mode-coupling-theory method for conduction-diffusion and viscoelastic properties of strong electrolyte solutions. Furthermore, results are presented for dispersions of solvent-permeable particles, and particles with non-zero hydrodynamic surface slip. The concentration-dependent swelling of ionic microgels is discussed, as well as a far-reaching dynamic scaling behavior relating colloidal long- to short-time dynamics.

  9. Copper and trace element fractionation in electrokinetically treated methanogenic anaerobic granular sludge.

    PubMed

    Virkutyte, Jurate; van Hullebusch, Eric; Sillanpää, Mika; Lens, Piet

    2005-12-01

    The effect of electrokinetic treatment (0.15 mA cm(-2)) on the metal fractionation in anaerobic granular sludge artificially contaminated with copper (initial copper concentration 1000 mg kg(-1) wet sludge) was studied. Acidification of the sludge (final pH 4.2 in the sludge bed) with the intention to desorb the copper species bound to the organic/sulfides and residual fractions did not result in an increased mobility, despite the fact that a higher quantity of copper was measured in the more mobile (i.e. exchangeable/carbonate) fractions at final pH 4.2 compared to circum-neutral pH conditions. Also addition of the chelating agent EDTA (Cu2+:EDTA4- ratio 1.2:1) did not enhance the mobility of copper from the organic/sulfides and residual fractions, despite the fact that it induced a reduction of the total copper content of the sludge. The presence of sulfide precipitates likely influences the copper mobilisation from these less mobile fractions, and thus makes EDTA addition ineffective to solubilise copper from the granules. PMID:15990208

  10. Simultaneous determination of flavonoids in Ixeridium gracile by micellar electrokinetic chromatography.

    PubMed

    Zhang, Yu; Chen, Juan; Ma, Xue-Mei; Shi, Yan-Ping

    2007-12-21

    A micellar electrokinetic chromatography (MEKC) method has been developed for the quantitative analysis of five flavonoids: luteolin 7-O-glucoside (LG), 2',4'-dihydroxy-dihydrochalcone (DD), 2',4'-dihydroxy-chalcone (DC), 7-hydroxy-flavanone (HF) and quercetin 3-O-galactoside (QG) in Ixeridium gracile with UV detection at 275 nm. The applied voltage was 25 kV and the capillary temperature was kept constant at 25 degrees C. The effects of buffer pH, the concentration of electrolyte and organic modifier on migration behavior were studied. Optimum separation condition was achieved with 15 mM borate, 30 mM sodium dodecyl sulfate (SDS) and 10% (v/v) ethanol at pH 10.5. Regression equations showed good linear relationships (correlation coefficients: 0.9984, 0.9991, 0.9994, 0.9995 and 0.9997) between the peak area of each compound and their concentrations. The relative standard deviations (R.S.D.) of the migration time and peak area were less 1.67 and 3.53% (intra-day), and 1.82 and 3.73% (inter-day), respectively, under the optimum separation conditions. The contents of the five active compounds in I. gracile were determined with satisfactory repeatability and recovery. PMID:17889478

  11. Enantioseparation of isoxanthohumol in beer by hydroxypropyl-gamma-cyclodextrin-modified micellar electrokinetic chromatography.

    PubMed

    Kodama, Shuji; Yamamoto, Atsushi; Sato, Atsushi; Suzuki, Kentaro; Yamashita, Tomohisa; Kemmei, Tomoko; Taga, Atsushi; Hayakawa, Kazuichi

    2007-08-01

    Chiral resolution of isoxanthohumol (IX) in beer samples was performed by hydroxypropyl-gamma-cyclodextrin-modified micellar electrokinetic chromatography. The optimum running conditions were found to be 20 mM phosphate buffer (pH 7.0) containing 45 mM hydroxypropyl-gamma-cyclodextrin and 100 mM sodium dodecyl sulfate with an effective voltage of +20 kV at 20 degrees C using direct detection at 210, 295, and 370 nm. IX was detected in 12 beer samples and the total levels of (+)- and (-)-IX ranged from 0.15 to 1.4 mg/L. But the amount of xanthohumol (XN) was below the detection limit (0.017 mg/L). Each level of (-)-IX was almost the same as that of (+)-IX, suggesting that IX was a racemic mixture in these beer samples. The racemization of IX in beer could be attributed to the production of a racemic mixture from XN during boiling and to the fact that IX enantiomers were easily interconverted. PMID:17629302

  12. Self-consistent description of electrokinetic phenomena in particle-based simulations

    E-print Network

    Juan P. Hernandez-Ortiz; Juan J. de Pablo

    2015-04-12

    A new computational method is presented for study suspensions of charged soft particles undergoing fluctuating hydrodynamic and electrostatic interactions. The proposed model is appropriate for polymers, proteins and porous particles embedded in a continuum electrolyte. A self-consistent Langevin description of the particles is adopted in which hydrodynamic and electrostatic interactions are included through a Green's function formalism. An Ewald-like split is adopted in order to satisfy arbitrary boundary conditions for the Stokeslet and Poisson Green functions, thereby providing a formalism that is applicable to any geometry and that can be extended to deformable objects. The convection-diffusion equation for the continuum ions is solved simultaneously considering Nernst-Planck diffusion. The method can be applied to systems at equilibrium and far from equilibrium. Its applicability is demonstrated in the context of electrokinetic motion, where it is shown that the ionic clouds associated with individual particles can be severely altered by the flow and concentration, leading to intriguing cooperative effects.

  13. Simultaneous determination of lovastatin and citrinin in red yeast rice supplements by micellar electrokinetic capillary chromatography.

    PubMed

    Nigovi?, Biljana; Serti?, Miranda; Mornar, Ana

    2013-05-01

    Lovastatin is a main component of Monascus purpureus fermented red rice contributing to the lipid-lowering effect. Citrinin is a toxic fermentation by-product which can be found as a contaminant. An accurate, simple and rapid micellar electrokinetic capillary chromatographic method was developed for the first time for simultaneous determination of lovastatin present in lactone and hydroxy acid forms and citrinin in red rice products provided by different manufacturers and formulated in various dosage forms. Separation was achieved within only 2 min using 20 mM of phosphate buffer at pH 7.0 and 30 mM of sodium dodecyl sulphate at an applied voltage of 25 kV. Sensitivity crucial for detecting citrinin was enhanced by using an extended light path capillary. The results showed that the content of lovastatin and its acid form in dietary supplements were considerably different indicating the need for improved standardization in order to ensure efficiency and safety of these products. PMID:23265521

  14. Self-consistent description of electrokinetic phenomena in particle-based simulations.

    PubMed

    Hernández-Ortiz, Juan P; de Pablo, Juan J

    2015-07-01

    A new computational method is presented for study suspensions of charged particles undergoing fluctuating hydrodynamic and electrostatic interactions. The proposed model is appropriate for polymers, proteins, and porous particles embedded in a continuum electrolyte. A self-consistent Langevin description of the particles is adopted in which hydrodynamic and electrostatic interactions are included through a Green's function formalism. An Ewald-like split is adopted in order to satisfy arbitrary boundary conditions for the Stokeslet and Poisson Green functions, thereby providing a formalism that is applicable to any geometry and that can be extended to deformable objects. The convection-diffusion equation for the continuum ions is solved simultaneously considering Nernst-Planck diffusion. The method can be applied to systems at equilibrium and far from equilibrium. Its applicability is demonstrated in the context of electrokinetic motion, where it is shown that the ionic clouds associated with individual particles can be severely altered by the flow and concentration, leading to intriguing cooperative effects. PMID:26156466

  15. [Determination of five coumarins in radix glehniae by micellar electrokinetic capillary chromatography].

    PubMed

    Liu, Man; Kong, Dezhi; Yang, Wei; Wang, Qiao; Zhang, Lantong

    2010-07-01

    A micellar electrokinetic capillary chromatography method with ultraviolet detection was developed for the simultaneous determination of psoralen, xanthotoxin, isoimpinellin, bergapten and scopoletin in Radix Glehniae. The separation was performed on an uncoated fused silica capillary column (50.2 cm x 75 microm x 40 cm) with 20 mmol x L(-1) borax solution (pH 9.6) containing 16 mmol x L(-1) sodium dodecylsulfate (SDS) and 15% acetonitrile as running buffer at applied voltage of 22 kV. The detection wavelength was 214 nm. The effects of concentrations of borax solution, sodium dodecylsulfate (SDS), and organic modifier, voltage, temperature on the separation and sensitivity were investigated. The five active constituents were completely separated within 7 min. The linear ranges of psoralen, xanthotoxin, isoimpinellin, bergapten and scopoletin were 9.91-82.6, 37.2-162, 2.23-18.6, 2.73-22.3 and 2.89-20.1 mg x L(-1), respectively. And the average recoveries were 98.9%, 98.4%, 101.3%, 99.1% and 98.0%, respectively. This simple and rapid method provided a new basis for assessment on quality of Radix Glehniae. PMID:20939281

  16. Simultaneous determination of five phytohormones in mungbean sprouts of China by micellar electrokinetic chromatography.

    PubMed

    Sun, Yue-Na; Qin, Xin-Ying; Lv, Yun-Kai; Li, Shan-Ze; Wei, Chen

    2014-08-01

    A simple and rapid micellar electrokinetic chromatography method was developed for simultaneous determination of indole-3-acetic acid, indole-3-butyric acid, gibberellic acid, abscisic acid and naphthylacetic acid in mungbean sprouts for monitoring plant growth and development. The effects of several parameters related to the separation and determination were investigated in detail. The analysis was carried out using 10 mM borax, 10 mM sodium dihydrogen phosphate, 90 mM sodium dodecyl sulfate and 5% acetonitrile as running buffer (pH 9.0). Under optimum conditions, the method demonstrated good performance concerning linearity (r, 0.9954-0.9991), precision (0.77-4.97%), the method limit of detection (LOD) and the method limit of quantitation (LOQ) (LOD, 0.011-0.177 mg/kg; LOQ, 0.035-0.590 mg/kg) and accuracy (83.62-102.56%). The results confirmed that the method is rapid, convenient and of low cost for the determination of the phytohormones. PMID:23845886

  17. Enhanced antitumor effect of anti-tissue factor antibody-conjugated epirubicin-incorporating micelles in xenograft models.

    PubMed

    Yamamoto, Yoshiyuki; Hyodo, Ichinosuke; Koga, Yoshikatsu; Tsumura, Ryo; Sato, Ryuta; Obonai, Toshihumi; Fuchigami, Hirobumi; Furuya, Fumiaki; Yasunaga, Masahiro; Harada, Mitsunori; Kato, Yasuki; Ohtsu, Atsushi; Matsumura, Yasuhiro

    2015-05-01

    For the creation of a successful antibody-drug conjugate (ADC), both scientific and clinical evidence has indicated that highly toxic anticancer agents (ACA) should be conjugated to a monoclonal antibody (mAb) to administer a reasonable amount of ADC to patients without compromising the affinity of the mAb. For ordinary ACA, the conjugation of a mAb to ACA-loaded micellar nanoparticles is clinically applicable. Tissue factor (TF) is often overexpressed in various cancer cells and tumor vascular endothelium. Accordingly, anti-TF-NC-6300, consisting of epirubicin-incorporating micelles (NC-6300) conjugated with the F(ab')2 of anti-TF mAb was developed. The in vitro and in vivo efficacy and pharmacokinetics of anti-TF-NC-6300 were compared to NC-6300 using two human pancreatic cancer cell lines, BxPC3 (high TF expression) and SUIT2 (low TF expression), and a gastric cancer cell line, 44As3 (high TF expression). The intracellular uptake of epirubicin was faster and greater in BxPC3 cells treated with anti-TF-NC-6300, compared with NC-6300. Anti-TF-NC-6300 showed a superior antitumor activity in BxPC3 and 44As3 xenografts, compared with NC-6300, while the activities of both micelles were similar in the SUIT2 xenograft. A higher tumor accumulation of anti-TF-NC-6300 compared to NC-6300 was seen, regardless of the TF expression levels. However, anti-TF-NC-6300 appeared to be localized to the tumor cells with high TF expression. These results indicated that the enhanced antitumor effect of anti-TF-NC6300 may be independent of the tumor accumulation but may depend on the selective intratumor localization and the preferential internalization of anti-TF-NC-6300 into high TF tumor cells. PMID:25711681

  18. Dose and time dependent effects of morphine on the incorporation of (3H)valine into soluble brain and liver proteins

    SciTech Connect

    Roennbaeck, L.; Hansson, E.; Cupello, A.

    1983-03-01

    Morphine (10(-6)-10(-5) M) causes an increase in incorporation of (/sup 3/H)valine into soluble proteins during 4 hr in rat brain cortical slices, liver slices and cultivated astroglial cells. The effects are dose-dependent. They are neither cell specific nor strictly related to classical opiate receptors. Pulse-labeling with (/sup 3/H)valine for 60 min after incubation in 10(-6)-10(-5) M morphine, resolves time-dependent changes in incorporation, with both increases and decreases in protein metabolism.

  19. Effect of hypoxia on the incorporation of (2-3H) glycerol and (1-14C(-palmitate into lipids of various brain regions

    SciTech Connect

    Alberghina, M.; Giuffrida, A.M.

    1981-01-01

    The lipid metabolism in guinea pig brain after intermittent hypoxia, prolonged for 80 hrs, was markedly impaired. The in vivo incorporation of (2-3H) glycerol and (1-14C) palmitate into lipids of microsomes, mitochondria, myelin, and synaptosomes, purified form cerebral hemispheres, was significantly lower in the hypoxic animals than in the controls. The same effect was observed on the incorporation of labeled precursors into lipids of mitochondria purified from cerebellum and brainstem. In particular, the labeling of th major phospholipids present - ie, phosphatidylcholine (PC) and phosphatidylethanolamine (PE) - in the mitochondria of the three brain regions examined decreased after hypoxic treatment.

  20. Using electrokinetic phenomena and electrical resistance tomography to characterize the movement of subsurface fluids

    DOEpatents

    Ramirez, A.L.; Cooper, J.F.; Daily, W.D.

    1996-02-27

    This invention relates generally to the remote detections of subsurface liquid contaminants using in combination a geophysical technique known as ERT and an EKS. Electrokinetic transport is used to enhance the ability of electrical resistance tomography (ERT) to detect position and movement of subsurface contaminant liquids, particles or ions. ERT images alone are difficult to interpret because of natural inhomogeneities in soil composition and electrical properties. By subtracting two or more ERT images obtained before and after field induced movement, a high contrast image of a plume of distinct electrokinetic properties can be seen. The invention is applicable to important subsurface characterization problems including, as examples, (1) detection of liquid-saturated plumes of contaminants such as those associated with leaks from underground storage tanks containing hazardous concentrated electrolytes, (2) detection and characterization of soils contaminated with organic pollutants such as droplets of gasoline; and (3) monitoring the progress of electrokinetic containment or clean up of underground contamination. 1 fig.

  1. Using electrokinetic phenomena and electrical resistance tomography to characterize the movement of subsurface fluids

    DOEpatents

    Ramirez, Abelardo L. (Pleasanton, CA); Cooper, John F. (Oakland, CA); Daily, William D. (Livermore, CA)

    1996-01-01

    This invention relates generally to the remote detections of subsurface liquid contaminants using in combination a geophysical technique known as ERT and an EKS. Electrokinetic transport is used to enhance the ability of electrical resistance tomography (ERT) to detect position and movement of subsurface contaminant liquids, particles or ions. ERT images alone are difficult to interpret because of natural inhomogeneities in soil composition and electrical properties. By subtracting two or more ERT images obtained before and after field induced movement, a high contrast image of a plume of distinct electrokinetic properties can be seen. The invention is applicable to important subsurface characterization problems including, as examples, (1) detection of liquid-saturated plumes of contaminants such as those associated with leaks from underground storage tanks containing hazardous concentrated electrolytes, (2) detection and characterization of soils contaminated with organic pollutants such as droplets of gasoline; and (3) monitoring the progress of electrokinetic containment or clean up of underground contamination.

  2. Soft particle analysis of electrokinetics of biological cells and their model systems

    NASA Astrophysics Data System (ADS)

    Makino, Kimiko; Ohshima, Hiroyuki

    2011-03-01

    In this article, we review the applications of a novel theory (Ohshima 2009 Sci. Technol. Adv. Mater. 10 063001) to the analysis of electrokinetic data for various soft particles, that is, particles covered with an ion-permeable surface layer of polyelectrolytes. Soft particles discussed in this review include various biological cells and hydrogel-coated particles as a model of biological cells. Cellular transformations increase the concentration of sialic acid of glycoproteins and are associated with blocked biosynthesis of glycolipids and aberrant expression of the developmentally programmed biosynthetic pathway. The change in shape or biological function of cells may affect their surface properties and can be detected by electrokinetic measurements. The experimental results were analyzed with Ohshima's electrokinetic formula for soft particles and soft surfaces. As a model system, hydrogel surfaces that mimic biological surfaces were also prepared and their surface properties were studied.

  3. Optimization and validation of a micellar electrokinetic chromatographic method for the analysis of several angiotensin-II-receptor antagonists.

    PubMed

    Hillaert, S; De Beer, T R M; De Beer, J O; Van den Bossche, W

    2003-01-10

    We have optimized a micellar electrokinetic capillary chromatographic method for the separation of six angiotensin-II-receptor antagonists (ARA-IIs): candesartan, eprosartan mesylate, irbesartan, losartan potassium, telmisartan, and valsartan. A face-centred central composite design was applied to study the effect of the pH, the molarity of the running buffer, and the concentration of the micelle-forming agent on the separation properties. A combination of the studied parameters permitted the separation of the six ARA-IIs, which was best carried out using a 55-mM sodium phosphate buffer solution (pH 6.5) containing 15 mM of sodium dodecyl sulfate. The same system can also be applied for the quantitative determination of these compounds, but only for the more stable ARA-IIs (candesartan, eprosartan mesylate, losartan potassium, and valsartan). Some system parameters (linearity, precision, and accuracy) were validated. PMID:12564683

  4. Enhanced transport of materials into enamel nanopores via electrokinetic flow.

    PubMed

    Gan, H Y; Sousa, F B; Carlo, H L; Maciel, P P; Macena, M S; Han, J

    2015-04-01

    The ability to infiltrate various molecules and resins into dental enamel is highly desirable in dentistry, yet transporting materials into dental enamel is limited by the nanometric scale of their pores. Materials that cannot be infiltrated into enamel by diffusion/capillarity are often considered molecules with sizes above a critical threshold, which are often considered to be larger than the pores of enamel. We challenge this notion by reporting the use of electrokinetic flow to transport solutions with molecules with sizes above a critical threshold-namely, an aqueous solution with a high refractive index (Thoulet's solution) and a curable fluid resin infiltrant (without acid etching)-deep into the normal enamel layer. Volume infiltration by Thoulet's solution is increased by 5- to 6-fold, and resin infiltration depths as large as 600 to 2,000 µm were achieved, in contrast to ~10 µm resulting from diffusion/capillarity. Incubation with demineralization solution for 192 h resulted in significant demineralization at noninfiltrated histologic points but not at resin infiltrated. These results open new avenues for the transport of materials in dental enamel. PMID:25691072

  5. Chiral Recognition and Enantioseparation Mechanisms in Capillary Electrokinetic Chromatography

    NASA Astrophysics Data System (ADS)

    Chankvetadze, Bezhan

    This chapter deals with the basic theory of enantiomeric separations in electrokinetic chromatography (EKC) in general and with the relationships between the recognition and the separation of enantiomers in EKC, in particular. It is important to note that the dependence between recognition and separation is not as straightforward in EKC as it is in chromatographic separation techniques. Therefore, a clear understanding of these dependences is very important for the explanation of experimentally observed results, as well as for a design of new powerful separation systems, technologies, and materials. Cyclodextrins (CDs) are mainly discussed as chiral selectors not only because the author has a long-term experience of working with these multifunctional macrocycles but also because CDs belong to the most widely used chiral selectors in EKC. In addition, these materials are quite well-characterized molecules of medium size. In addition, CDs are used for separation of enantiomers almost in all analytical separation techniques, as well as for determination of the enantiomeric excess in nonseparation techniques such as nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry. This chapter does not address applications of chiral EKC in chemistry, pharmaceutical and biomedical, environmental, and food analyses.

  6. Separation of some chiral flavanones by micellar electrokinetic chromatography.

    PubMed

    Asztemborska, Monika; Mi?kiewicz, Magdalena; Sybilska, Danuta

    2003-08-01

    Micellar electrokinetic chromatography (MEKC) was applied for enantioseparation of selected flavanones, including naringin, hesperidin, neohesperidin, naringenin, hesperetin, pinostrobin, isosakuranetin, eriodictyol, and homoeriodictyol. gamma-Cyclodextrin (gamma-CD) and sodium cholate (SCh) were used as chiral modifiers inducing enantioselectivity to the background electrolyte. From among many investigated selectors only these two appeared to possess the best enantioselective properties in respect to studied flavanones. The mechanisms of their action are a little different; SCh used above critical micelle point concentration forms chiral micelles itself while gamma-CD is deprived of this property and requires addition of surfactants as, e.g., sodium dodecyl sulfate. It was found that SCh enables separation of flavanone glycosides diastereomers while separation of enantiomers of flavanone aglycones may be achieved with gamma-CD. Consideration of structural relation led to the suggestion that interaction of sugar moiety of glycosides with SCh micelles give rise to chiral recognition. MEKC appeared to be a suitable and efficient analytical tool to follow enantiomeric composition of flavanones. PMID:12900864

  7. Multi-vortical flow inducing electrokinetic instability in ion concentration polarization layer

    NASA Astrophysics Data System (ADS)

    Kim, Sung Jae; Ko, Sung Hee; Kwak, Rhokyun; Posner, Jonathan D.; Kang, Kwan Hyoung; Han, Jongyoon

    2012-11-01

    In this work, we investigated multiple vortical flows inside the ion concentration polarization (ICP) layer that forms due to a coupling of applied electric fields and the semipermeable nanoporous junction between microchannels. While only a primary vortex near perm-selective membrane is traditionally known to lead to electrokinetic instability, multiple vortexes induced by the primary vortex were found to play a major role in the electrokinetic instability. The existence of multiple vortexes was directly confirmed by experiments using particle tracers and interdigitated electrodes were used to measure the local concentration profile inside the ICP layer. At larger applied electric fields, we observed aperiodic fluid motion due to electrokinetic instabilities which develop from a coupling of applied electric fields and electrical conductivity gradients induced by the ICP. The electrokinetic instability at micro-nanofluidic interfaces is important in the development of various electro-chemical-mechanical applications such as fuel cells, bio-analytical preconcentration methods, water purification/desalination and the fundamental study of ion electromigration through nanochannels and nonporous perm-selective membranes.In this work, we investigated multiple vortical flows inside the ion concentration polarization (ICP) layer that forms due to a coupling of applied electric fields and the semipermeable nanoporous junction between microchannels. While only a primary vortex near perm-selective membrane is traditionally known to lead to electrokinetic instability, multiple vortexes induced by the primary vortex were found to play a major role in the electrokinetic instability. The existence of multiple vortexes was directly confirmed by experiments using particle tracers and interdigitated electrodes were used to measure the local concentration profile inside the ICP layer. At larger applied electric fields, we observed aperiodic fluid motion due to electrokinetic instabilities which develop from a coupling of applied electric fields and electrical conductivity gradients induced by the ICP. The electrokinetic instability at micro-nanofluidic interfaces is important in the development of various electro-chemical-mechanical applications such as fuel cells, bio-analytical preconcentration methods, water purification/desalination and the fundamental study of ion electromigration through nanochannels and nonporous perm-selective membranes. Electronic supplementary information (ESI) available. See DOI: 10.1039/c2nr32467a

  8. Effect of liquid swine manure rate, incorporation, and timing of rainfall on phosphorus loss with surface runoff

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Excessive manure P application increases risk of P loss from fields. This study assessed total (TPR), bioavailable (BAP), and dissolved reactive (DRP) P concentrations and loads in surface runoff following liquid swine (Sus scrofa domesticus) manure application with or without incorporation into soi...

  9. The Effects of Incorporation into the World-System on Ethnic Persistence: The American Conquest of the Southwest.

    ERIC Educational Resources Information Center

    Hall, Thomas D.

    The varying results of incorporation on the survival of groups such as bands, tribes, chiefdoms and mercantile states can be explained by applying the historical process to the American conquest of the Southwest. The American Southwest (the region covered by Arizona, New Mexico, parts of Texas, California, Utah, Nevada, and Colorado) was occupied…

  10. On the effects of circulation, sediment resuspension and biological incorporation by diatoms in an ocean model of aluminium*

    NASA Astrophysics Data System (ADS)

    van Hulten, M. M. P.; Sterl, A.; Middag, R.; de Baar, H. J. W.; Gehlen, M.; Dutay, J.-C.; Tagliabue, A.

    2014-07-01

    The distribution of dissolved aluminium in the West Atlantic Ocean shows a mirror image with that of dissolved silicic acid, hinting at intricate interactions between the ocean cycling of Al and Si. The marine biogeochemistry of Al is of interest because of its potential impact on diatom opal remineralisation, hence Si availability. Furthermore, the dissolved Al concentration at the surface ocean has been used as a tracer for dust input, dust being the most important source of the bio-essential trace element iron to the ocean. Previously, the dissolved concentration of Al was simulated reasonably well with only a dust source, and scavenging by adsorption on settling biogenic debris as the only removal process. Here we explore the impacts of (i) a sediment source of Al in the Northern Hemisphere (especially north of 40degree N), (ii) the imposed velocity field, and (iii) biological incorporation of Al on the modelled Al distribution in the ocean. The sediment source clearly improves the model results, and using a different velocity field shows the importance of advection on the simulated Al distribution. Biological incorporation appears to be a potentially important removal process. However, conclusive independent data to constrain the Al / Si incorporation ratio by growing diatoms are missing. Therefore, this study does not provide a definitive answer to the question of the relative importance of Al removal by incorporation compared to removal by adsorptive scavenging.

  11. Incorporation of fatty acids by concanavalin A-stimulated lymphocytes and the effect on fatty acid composition and membrane fluidity.

    PubMed Central

    Calder, P C; Yaqoob, P; Harvey, D J; Watts, A; Newsholme, E A

    1994-01-01

    The fatty acid compositions of the neutral lipid and phospholipid fractions of rat lymph node lymphocytes were characterized. Stimulation of rat lymphocytes with the T-cell mitogen concanavalin A resulted in significant changes in the fatty acid composition of both neutral lipids and phospholipids (a decrease in the proportions of stearic, linoleic and arachidonic acids and an increase in the proportion of oleic acid). Membrane fluidity was measured using nitroxide spin-label e.s.r., and increased during culture with concanavalin A. Culturing the lymphocytes in the absence of mitogen did not affect fatty acid composition or membrane fluidity. The uptake and fate of palmitic, oleic, linoleic and arachidonic acids were studied in detail; there was a time-dependent incorporation of each fatty acid into all lipid classes but each fatty acid had a characteristic fate. Palmitic and arachidonic acids were incorporated principally into phospholipids whereas oleic and linoleic acids were incorporated in similar proportions into phospholipids and triacylglycerols. Oleic acid was incorporated mainly into phosphatidylcholine, palmitic and linoleic acids were incorporated equally into phosphatidylcholine and phosphatidylethanolamine, and arachidonic acid was incorporated mainly into phosphatidylethanolamine. Supplementation of the culture medium with particular fatty acids (myristic, palmitic, stearic, oleic, linoleic, alpha-linolenic, arachidonic, eicosapentaenoic or docosahexaenoic acid) led to enrichment of that fatty acid in both neutral lipids and phospholipids. This generated lymphocytes with phospholipids differing in saturated/unsaturated fatty acid ratio, degree of polyunsaturation, index of unsaturation and n - 6/n - 3 ratio. This method allowed the introduction into lymphocyte phospholipids of fatty acids not normally present (e.g. alpha-linolenic) or usually present in low proportions (eicosapentaenoic and docosahexaenoic). These three n - 3 polyunsaturated fatty acids replaced arachidonic acid in lymphocyte phospholipids. Fatty acid incorporation led to an alteration in lymphocyte membrane fluidity: palmitic and stearic acids decreased fluidity whereas the unsaturated fatty acids increased fluidity. It is proposed that the changes in lymphocyte phospholipid fatty acid composition and membrane fluidity brought about by culture in the presence of polyunsaturated fatty acids are responsible for the inhibition of lymphocyte functions caused by these fatty acids. PMID:8002957

  12. A three-scale model for ionic solute transport in swelling clays incorporating ion-ion correlation effects

    NASA Astrophysics Data System (ADS)

    Le, Tien Dung; Moyne, Christian; Murad, Marcio A.

    2015-01-01

    A new three-scale model is proposed to describe the movement of ionic species of different valences in swelling clays characterized by three separate length scales (nano, micro, and macro) and two levels of porosity (nano- and micropores). At the finest (nano) scale the medium is treated as charged clay particles saturated by aqueous electrolyte solution containing monovalent and divalent ions forming the electrical double layer. A new constitutive law is constructed for the disjoining pressure based on the numerical resolution of non-local problem at the nanoscale which, in contrast to the Poisson-Boltzmann theory for point charge ions, is capable of capturing the short-range interactions between the ions due to their finite size. At the intermediate scale (microscale), the two-phase homogenized particle/electrolyte solution system is represented by swollen clay clusters (or aggregates) with the nanoscale disjoining pressure incorporated in a modified form of Terzaghi's effective principle. At the macroscale, the electro-chemical-mechanical couplings within clay clusters is homogenized with the ion transport in the bulk fluid lying in the micro pores. The resultant macroscopic picture is governed by a three-scale model wherein ion transport takes place in the bulk solution strongly coupled with the mechanics of the clay clusters which play the role of sources/sinks of mass to the bulk fluid associated with ion adsorption/desorption in the electrical double layer at the nanoscale. Within the context of the quasi-steady version of the multiscale model, wherein the electrolyte solution in the nanopores is assumed at instantaneous thermodynamic equilibrium with the bulk fluid in the micropores, we build-up numerically the ion-adsorption isotherms along with the constitutive law of the retardation coefficients of monovalent and divalent ions. In addition, the constitutive law for the macroscopic swelling pressure is reconstructed numerically showing patterns of attractive forces between particles for bivalent ions for particular ranges of bulk concentrations. The three-scale model is applied to numerically simulate ion diffusion in a compacted clay liner underneath a sanitary landfill. Owing to the distinct constitutive behavior of the swelling pressure and partition coefficient for each ionic species, different compaction regimes and diffusion/adsorption patterns, with totally different characteristic time scales, are observed for sodium and calcium migration in the clay liner.

  13. The effect of increasing nucleotide-sugar concentrations on the incorporation of sugars into glycoconjugates in rat hepatocytes.

    PubMed Central

    Pels Rijcken, W R; Overdijk, B; Van den Eijnden, D H; Ferwerda, W

    1995-01-01

    Treatment of rat hepatocytes with 0.5 mM concentrations of uridine and cytidine results in increased cellular concentrations of UTP, UDP-sugars and CTP, whereas that of CMP-N-acetylneuraminate remained unchanged [Pels Rijcken, Overdijk, Van den Eijnden and Ferwerda (1993) Biochem. J. 293, 207-213]. The incorporation of radioactivity from 3H-labelled sugars into the cell-associated and secreted glycoconjugate fraction was influenced by these altered cellular concentrations of the nucleotides. For [3H]glucosamine, pretreatment with uridine resulted in a reduction of the glycosylation in both fractions. Increases in the secreted fractions were observed for fucose with both uridine and cytidine and for N-acetylglucosamine with uridine only. With [3H]N-acetylglucosamine, similar specific radioactivities for UDP-N-acetylhexosamine and CMP-N-acetylneuraminate were found, regardless of the pretreatment conditions. With [3H]N-acetylmannosamine, the specific radioactivity of CMP-N-acetylneuraminate showed an almost 2-fold increase on pretreatment. The latter increase did not result in an increased incorporation of radioactivity into the glycoconjugates. It was estimated that, in untreated cells, the ratio of radioactivity incorporated from [3H]glucosamine into glycoconjugate-bound N-acetylhexosamine and N-acetylneuraminate amounted to 2:3. In pretreated cells this ratio changed to approx. 2:1. Overall, the data show that pretreatment resulted in an increased incorporation of N-acetylhexosamine into cell-associated and secreted glycoconjugates, accompanied by a reduction in sialylation. It was concluded that an increased availability of UDP-N-acetylhexosamine caused the increased incorporation of N-acetylhexosamine. The elevated cytosolic level of UDP-N-acetylhexosamine (and of compounds like CMP) is suggested to impair the transport of CMP-acetylneuraminate to the Golgi, resulting in reduced sialylation. This study demonstrates that protein glycosylation can be regulated at the level of the availability of the various nucleotide-sugars in the Golgi lumen. PMID:7848287

  14. Application of iron electrode corrosion enhanced electrokinetic-Fenton oxidation to remediate diesel contaminated soils: A laboratory feasibility study

    NASA Astrophysics Data System (ADS)

    Tsai, Tzai-Tang; Sah, Jygau; Kao, Chih-Ming

    2010-01-01

    SummaryDiesel soil contamination on gas stations or refinery plants is a worldwide environmental problem. The main objectives of this study were to (1) evaluate the efficiency of electrokinetic (EK) by using different electrode materials (graphite and iron rods) and electrolytes (tap water, 0.01 M NaCl, and 0.1 M NaCl) on the remediation of diesel contaminated soils, and (2) evaluate the feasibility of total petroleum hydrocarbon-diesel (TPH-D) reducing in soils via EK-Fenton oxidation enhanced by corroded iron electrode. The EK and EK-Fenton experiments were conducted in batch and sand box experiments, respectively. Batch experiments reveal that the most appropriate electrolyte was 0.1 M NaCl when iron electrode was used in the EK system. Sand box experiments indicate that the TPH-D concentration dropped from 10,000 to 300 mg kg -1 when amorphous iron/total iron (Fe o/Fe t) ratio increased from 0.1 to 0.33, with the addition of 8% of H 2O 2 and 0.1 M NaCl after 60 days of EK-Fenton operation. Electrokinetically enhanced oxidation with the presence of both H 2O 2 and Fe 3O 4 (iron electrode corrosion) resulted in higher TPH-D removal efficiency (97%) compared to the efficiencies observed from EK (55%) or Fenton oxidation (27%) alone. This demonstrates that EK-Fenton oxidation catalyzed by iron electrode corrosion is a valuable direction to efficiently and effectively remediate diesel contaminated soils.

  15. Effects of Cholesterol Incorporation on the Physicochemical, Colloidal, and Biological Characteristics of pH-sensitive AB2 Miktoarm Polymer-Based Polymersomes

    PubMed Central

    Yin, Haiqing; Kang, Han Chang; Huh, Kang Moo; Bae, You Han

    2014-01-01

    In our previous study, a histidine-based AB2 miktoarm polymer, methoxy poly(ethylene glycol)-b-poly(l-histidine)2 (mPEG-b-(PolyHis)2), was designed to construct pH-sensitive polymersomes that transform in acidic pH; the polymer self-assembles into a structure that mimics phospholipids. In this study, the polymersomes further imitated liposomes due to the incorporation of cholesterol (CL). The hydrodynamic radii of the polymersomes increased with increasing CL wt% (e.g., 70 nm for 0 wt% vs. 91 nm for 1 wt%), resulting in an increased capacity for encapsulating hydrophilic drugs (e.g., 0.92 µL/mg for 0 wt% vs. 1.42 µL/mg for 1 wt%). The CL incorporation enhanced the colloidal stability of the polymersomes in the presence of serum protein and retarded their payload release. However, CL-incorporating polymersomes still demonstrated accelerated release of a hydrophilic dye (e.g., 5(6)-carboxyfluorescein (CF)) below pH 6.8 without losing their desirable pH sensitivity. CF-loaded CL-incorporating polymersomes showed better cellular internalization than the hydrophilic CF, whereas doxorubicin (DOX)-loaded CL-incorporating polymersomes presented similar or somewhat lower anti-tumor effects than free hydrophobic DOX. The findings suggest that CL-incorporating mPEG-b-(PolyHis)2-based polymersomes may have potential for intracellular drug delivery of chemical drugs due to their improved colloidal stability, lower drug loss during circulation, acidic pH-induced drug release, and endosomal disruption. PMID:24463148

  16. Effects of cholesterol incorporation on the physicochemical, colloidal, and biological characteristics of pH-sensitive AB? miktoarm polymer-based polymersomes.

    PubMed

    Yin, Haiqing; Kang, Han Chang; Huh, Kang Moo; Bae, You Han

    2014-04-01

    In our previous study, a histidine-based AB2 miktoarm polymer, methoxy poly(ethylene glycol)-b-poly(l-histidine)2 (mPEG-b-(PolyHis)2), was designed to construct pH-sensitive polymersomes that transform in acidic pH; the polymer self-assembles into a structure that mimics phospholipids. In this study, the polymersomes further imitated liposomes due to the incorporation of cholesterol (CL). The hydrodynamic radii of the polymersomes increased with increasing CLwt% (e.g., 70 nm for 0 wt% vs. 91 nm for 1 wt%), resulting in an increased capacity for encapsulating hydrophilic drugs (e.g., 0.92 ?L/mg for 0 wt% vs. 1.42 ?L/mg for 1 wt%). The CL incorporation enhanced the colloidal stability of the polymersomes in the presence of serum protein and retarded their payload release. However, CL-incorporating polymersomes still demonstrated accelerated release of a hydrophilic dye (e.g., 5(6)-carboxyfluorescein (CF)) below pH 6.8 without losing their desirable pH sensitivity. CF-loaded CL-incorporating polymersomes showed better cellular internalization than the hydrophilic CF, whereas doxorubicin (DOX)-loaded CL-incorporating polymersomes presented similar or somewhat lower anti-tumor effects than free hydrophobic DOX. The findings suggest that CL-incorporating mPEG-b-(PolyHis)2-based polymersomes may have potential for intracellular drug delivery of chemical drugs due to their improved colloidal stability, lower drug loss during circulation, acidic pH-induced drug release, and endosomal disruption. PMID:24463148

  17. Binary electrokinetic separation of target DNA from background DNA primers.

    SciTech Connect

    James, Conrad D.; Derzon, Mark Steven

    2005-10-01

    This report contains the summary of LDRD project 91312, titled ''Binary Electrokinetic Separation of Target DNA from Background DNA Primers''. This work is the first product of a collaboration with Columbia University and the Northeast BioDefense Center of Excellence. In conjunction with Ian Lipkin's lab, we are developing a technique to reduce false positive events, due to the detection of unhybridized reporter molecules, in a sensitive and multiplexed detection scheme for nucleic acids developed by the Lipkin lab. This is the most significant problem in the operation of their capability. As they are developing the tools for rapidly detecting the entire panel of hemorrhagic fevers this technology will immediately serve an important national need. The goal of this work was to attempt to separate nucleic acid from a preprocessed sample. We demonstrated the preconcentration of kilobase-pair length double-stranded DNA targets, and observed little preconcentration of 60 base-pair length single-stranded DNA probes. These objectives were accomplished in microdevice formats that are compatible with larger detection systems for sample pre-processing. Combined with Columbia's expertise, this technology would enable a unique, fast, and potentially compact method for detecting/identifying genetically-modified organisms and multiplexed rapid nucleic acid identification. Another competing approach is the DARPA funded IRIS Pharmaceutical TIGER platform which requires many hours for operation, and an 800k$ piece of equipment that fills a room. The Columbia/SNL system could provide a result in 30 minutes, at the cost of a few thousand dollars for the platform, and would be the size of a shoebox or smaller.

  18. Effect of liquid swine manure rate, incorporation, and timing of rainfall on phosphorus loss with surface runoff.

    PubMed

    Allen, Brett L; Mallarino, Antonio P

    2008-01-01

    Excessive manure phosphorus (P) application increases risk of P loss from fields. This study assessed total runoff P (TPR), bioavailable P (BAP), and dissolved reactive P (DRP) concentrations and loads in surface runoff after liquid swine (Sus scrofa domesticus) manure application with or without incorporation into soil and different timing of rainfall. Four replicated manure P treatments were applied in 2002 and in 2003 to two Iowa soils testing low in P managed with corn (Zea mays L.)-soybean [Glycine max (L.) Merr.] rotations. Total P applied each time was 0 to 80 kg P ha(-1) at one site and 0 to 108 kg P ha(-1) at the other. Simulated rainfall was applied within 24 h of P application or after 10 to 16 d and 5 to 6 mo. Nonincorporated manure P increased DRP, BAP, and TPR concentrations and loads linearly or exponentially for 24-h and 10- to 16-d runoff events. On average for the 24-h events, DRP, BAP, and TPR concentrations were 5.4, 4.7, and 2.2 times higher, respectively, for nonincorporated manure than for incorporated manure; P loads were 3.8, 7.7, and 3.6 times higher; and DRP and BAP concentrations were 54% of TPR for nonincorporated manure and 22 to 25% for incorporated manure. A 10- to 16-d rainfall delay resulted in DRP, BAP, and TPR concentrations that were 3.1, 2.7, and 1.1 times lower, respectively, than for 24-h events across all nonincorporated P rates, sites, and years, whereas runoff P loads were 3.8, 3.6, and 1.6 times lower, respectively. A 5- to 6-mo simulated rainfall delay reduced runoff P to levels similar to control plots. Incorporating swine manure when the probability of immediate rainfall is high reduces the risk of P loss in surface runoff; however, this benefit sharply decreases with time. PMID:18178885

  19. Study on Effect of Incorporation of Gelatin Fiber in Jute Fabrics-Reinforced Linear Low Density Polyethylene Composite

    Microsoft Academic Search

    Bapi Sarker; Ruhul A. Khan

    2011-01-01

    Jute fabrics (50%)-reinforced linear low density polyethylene (LLDPE) composite was prepared by compression molding and mechanical properties were studied. Gelatin fiber (2%–10%) was incorporated into the jute fabrics-based composites and their mechanical properties were investigated and compared with the control composite. It was found that with the increased of gelatin fiber content in the jute fabrics-based composites, the mechanical properties

  20. HIV1 Vpr-chloramphenicol acetyltransferase fusion proteins: sequence requirement for virion incorporation and analysis of antiviral effect

    Microsoft Academic Search

    X-J Yao; G P Kobinger; S Dandache; N Rougeau; E A Cohen

    1999-01-01

    The human immunodeficiency virus type 1 Vpr is a virion-associated protein that is incorporated in trans into viral particles, presumably via an interaction with the p6 domain of the Gag polyprotein precursor. Recently, several studies demonstrated that Vpr fusion proteins could be used as intravirion inactivating agents. In this study, we compared different Vpr-chloramphenicol acetyltransferase (CAT) fusion proteins for their

  1. Effect of interface incorporation of cadmium nanocrystallites on the photovoltaic performance of solar cells based on CdS/Si multi-interface nanoheterojunction

    NASA Astrophysics Data System (ADS)

    Li, Yong; Wang, Xiao Bo; Tian, Yong Tao; Li, Xin Jian

    2014-11-01

    A non-planar and multi-interface CdS/Si nanoheterojunction was prepared by growing CdS nanocrystallites (nc-CdS) onto silicon nanoporous pillar array (Si-NPA) using a chemical bath deposition (CBD) method. Utilizing the surface reducibility of Si-NPA, small quantities of Cd nanocrystallites (nc-Cd) were incorporated naturally into the CdS-Si interface during the CBD process. Solar cells with a device construction of ITO/CdS/Si-NPA/Al were prepared based on CdS/Si-NPA and their photovoltaic performances, including open circuit voltage, short circuit current density, external quantum efficiency and energy conversion efficiency, were measured under simulated AM 1.5 G illumination. Compared with CdS/Si-NPA cells without nc-Cd incorporation, an energy conversion efficiency promotion by two orders of magnitude was achieved, which was ascribed to the reduction of the series resistance resulted from the nc-Cd incorporation at the interface. Our results show that the incorporation of nc-Cd at CdS-Si interface might be an effective path for obtaining high-efficiency solar cells based on CdS/Si multi-interface nanoheterojunctions.

  2. Sample Collection, Preparation, and Quantitation in the Micellar Electrokinetic Capillary Electrophoresis of Gunshot Residues

    Microsoft Academic Search

    David M. Northrop; William A. Mac Crehan

    1992-01-01

    Application of micellar electrokinetic capillary electrophoresis (MECE) to gunshot residue (GSR) analysis was accomplished by developing appropriate sample collection and handling techniques. Masking adhesive-tape particle collection was used to minimize analyte losses and coextraction of sample matrix interferences associated with solvent swabbing collection methods. In addition, ethylene glycol (EG) was added to the extraction solvent to prevent analyte loss during

  3. Electrokinetics of colloidal particles in nonpolar media containing charged inverse micelles

    Microsoft Academic Search

    Filip Strubbe; Filip Beunis; Matthias Marescaux; Bart Verboven; Kristiaan Neyts

    2008-01-01

    We have compared optical tracking and electric current measurements to study the electrokinetics of colloidal particles in nonpolar media containing charged inverse micelles. Particle trajectories are measured in response to a voltage step, revealing spatial and temporal variations of the electric field when space-charge layers are created by charged inverse micelles. The particle trajectories and current measurements are in good

  4. Multi-vortical flow inducing electrokinetic instability in ion concentration polarization layer.

    PubMed

    Kim, Sung Jae; Ko, Sung Hee; Kwak, Rhokyun; Posner, Jonathan D; Kang, Kwan Hyoung; Han, Jongyoon

    2012-12-01

    In this work, we investigated multiple vortical flows inside the ion concentration polarization (ICP) layer that forms due to a coupling of applied electric fields and the semipermeable nanoporous junction between microchannels. While only a primary vortex near perm-selective membrane is traditionally known to lead to electrokinetic instability, multiple vortexes induced by the primary vortex were found to play a major role in the electrokinetic instability. The existence of multiple vortexes was directly confirmed by experiments using particle tracers and interdigitated electrodes were used to measure the local concentration profile inside the ICP layer. At larger applied electric fields, we observed aperiodic fluid motion due to electrokinetic instabilities which develop from a coupling of applied electric fields and electrical conductivity gradients induced by the ICP. The electrokinetic instability at micro-nanofluidic interfaces is important in the development of various electro-chemical-mechanical applications such as fuel cells, bio-analytical preconcentration methods, water purification/desalination and the fundamental study of ion electromigration through nanochannels and nonporous perm-selective membranes. PMID:23085964

  5. Pore network model of electrokinetic transport through charged porous media Amael Obliger,1, 2, 3

    E-print Network

    Paris-Sud XI, Université de

    in the acceler- ation of the whole fluid under an applied electric field (electro-osmosis) and in the transportPore network model of electrokinetic transport through charged porous media Ama¨el Obliger,1, 2, 3 are computed within the framework of a Pore Network Model (PNM), which describes the pore structure

  6. AC Electrokinetic separation and detection of nanoparticles and DNA nanoparticulates under high conductance conditions

    E-print Network

    Krishnan, Rajaram

    2010-01-01

    blood and plasma. These include centrifugation, gel filtration, affinity binding, magnetic bead separation,blood and plasma was also tested and proven to work. Once this was accomplished, Separationblood and plasma. AC electrokinetic techniques xix  such as dielectrophoresis (DEP) offer a particularly attractive mechanism for the separation

  7. Hydrodynamic and Electrokinetic Properties of Decane Droplets in Aqueous Sodium Dodecyl Sulfate Solutions

    E-print Network

    Chan, Derek Y C

    Hydrodynamic and Electrokinetic Properties of Decane Droplets in Aqueous Sodium Dodecyl Sulfate, 2001 Electrophoretic mobilities of sodium dodecyl sulfate (SDS)-stabilized decane droplets of solid particles in terms of particle surface charge, surface potential, and double-layer thickness has

  8. Electrokinetic motion of polarizable particles Dielectrophoresis, induced-charge electrophoresis, electrophoresis of the second kind.

    E-print Network

    Bazant, Martin Z.

    -charge electrophoresis, electrophoresis of the second kind. Definition The electrokinetic motion of polarizable particles results from electro-osmotic flow (induced- charge electrophoresis) of the first of second kind, in addition to electrostatic forces (dielectrophoresis). Overview The classical theory of electrophoresis

  9. Quantitative determination of glucoraphanin in Brassica vegetables by micellar electrokinetic capillary chromatography

    Microsoft Academic Search

    Iris Lee; Mary C. Boyce; Michael C. Breadmore

    2010-01-01

    Glucoraphanin, a glucosinolate, is found naturally in plants and is present in relatively high concentrations in broccoli. Glucosinolates have received much attention as studies have indicated that a diet rich in them may provide some protection from certain cancers. A micellar electrokinetic chromatography (MEKC) method using sodium cholate as the micellar phase has been developed to quantify for glucoraphanin in

  10. Determination of ferulic acid and adenosine in Angelicae Radix by micellar electrokinetic chromatography

    Microsoft Academic Search

    Tao Guo; Yi Sun; Yin Sui; Famei Li

    2003-01-01

    A micellar electrokinetic chromatography for determining ferulic acid and adenosine in Angelicae Radix was developed. A buffer solution composed of 50 mmol Lу borax, 10 mmol Lу sodium deoxycholate, and 2% methanol was found to be the most suitable electrolyte for the separation. The contents of ferulic acid and adenosine in Angelicae Radix were determined within 20 min. Good linearity

  11. Quantitative analysis of flavonoids and phenolic acids in Arnica montana L. by micellar electrokinetic capillary chromatography

    Microsoft Academic Search

    Markus Ganzera; Christoph Egger; Christian Zidorn; Hermann Stuppner

    2008-01-01

    Arnica montana preparations have been used in Europe for centuries to treat skin disorders. Among the biologically active ingredients in the flower heads of the plant are sequiterpenes, flavonoids and phenolic acids. For the simultaneous determination of compounds belonging to the latter two groups a micellar electrokinetic capillary chromatography (MEKC) method was developed and validated. By using an electrolyte solution

  12. Systematic optimization of exhaustive electrokinetic injection combined with micellar sweeping in capillary electrophoresis

    E-print Network

    Chen, David D.Y.

    -amplified sample injection. At optimal conditions, we were able to analyze three amine drugs (amphetamine molecules at different locations of the capillary.5 Online concentration techniques have been increasingly with sweeping in micellar electrokinetic chromatography (MEKC), online concentration can achieve even greater

  13. The effect of dietary lecithin and lipase, as a function of age, on n-9 fatty acid incorporation in the tissue lipids of Sparus aurata larvae

    Microsoft Academic Search

    W. M. Koven; S. Kolkovski; A. Tandler; G. Wm. Kissil; D. Sklan

    1993-01-01

    The present study tested the effect of dietary lecithin and exogenous lipase on the incorporation of oleic acid in the tissue lipids of gilthead seabream larvae (Sparus aurata). Two of four microdiets were prepared by the addition of [14C]oleic acid as free fatty acid (FFA) to diets containing either 5% cuttlefish liver oil (CLO) or 5% soybean lecithin. Glycerol tri[1-14C]oleate

  14. Characterization of electrokinetic mobility of microparticles in order to improve dielectrophoretic concentration.

    PubMed

    Martínez-López, José I; Moncada-Hernández, Héctor; Baylon-Cardiel, Javier L; Martínez-Chapa, Sergio O; Rito-Palomares, Marco; Lapizco-Encinas, Blanca H

    2009-05-01

    Insulator-based dielectrophoresis (iDEP), an efficient technique with great potential for miniaturization, has been successfully applied for the manipulation of a wide variety of bioparticles. When iDEP is applied employing direct current (DC) electric fields, other electrokinetic transport mechanisms are present: electrophoresis and electroosmotic flow. In order to concentrate particles, iDEP has to overcome electrokinetics. This study presents the characterization of electrokinetic flow under the operating conditions employed with iDEP; in order to identify the optimal conditions for particle concentration employing DC-iDEP, microparticle image velocimetry (microPIV) was employed to measure the velocity of 1-microm-diameter inert polystyrene particles suspended inside a microchannel made from glass. Experiments were carried out by varying the properties of the suspending medium (conductivity from 25 to 100 microS/cm and pH from 6 to 9) and the strength of the applied electric field (50-300 V/cm); the velocities values obtained ranged from 100 to 700 microm/s. These showed that higher conductivity and lower pH values for the suspending medium produced the lowest electrokinetic flow, improving iDEP concentration of particles, which decreases voltage requirements. These ideal conditions for iDEP trapping (pH = 6 and sigma(m) = 100 microS/cm) were tested experimentally and with the aid of mathematical modeling. The microPIV measurements allowed obtaining values for the electrokinetic mobilities of the particles and the zeta potential of the glass surface; these values were used with a mathematical model built with COMSOL Multiphysics software in order to predict the dielectrophoretic and electrokinetic forces exerted on the particles; the modeling results confirmed the microPIV findings. Experiments with iDEP were carried out employing the same microparticles and a glass microchannel that contained an array of cylindrical insulating structures. By applying DC electric fields across the insulating structures array, it was seen that the dielectrophoretic trapping was improved when the electrokinetic force was the lowest; as predicted by microPIV measurements and the mathematical model. The results of this study provide guidelines for the selection of optimal operating conditions for improving insulator-based dielectrophoretic separations and have the potential to be extended to bioparticle applications. PMID:19190896

  15. Electrokinetically enhanced flow and dewatering characteristics of concentrated black coal-water suspensions in pipes

    SciTech Connect

    Rozakeas, P.K.; Snow, R.J. [Royal Melbourne Inst. of Technology, Victoria (Australia)

    1997-07-01

    The transportability and dewatering of coal-water mixtures flowing in a pipe may be enhanced by the application of electrokinetic techniques. Previous experimental work by other workers shows a significant reduction in the wall shear stress, and consequently a decrease in pumping energy requirements for the flow of coal-water mixtures in pipes combined with electrodewatering. In this process the pipe wall acts as the cathode and a centrally aligned tube as the anode. The effects of {open_quote}In-pipe electrodewatering{close_quote} on the flow properties and stability of concentrated coal-water mixtures flowing in various alternative anode-cathode arrangements are presented in this paper. The application of an electrical energy flux at the electrode surface (< 6.1 kW/m{sup 2}) in a dewatering section of pipe (L{sub e}=1m) effectively reduces the pumping energy requirements by as much as one order of magnitude. The stability of flow conditions is investigated in a concentric anode-cathode pipe arrangement consisting of a dewatering and a non-dewatering section (L{sub o}). In this system (L{sub o}/L{sub e}) < 4.0. A microscopic study of dilute coal-water suspensions in the presence of a DC electric field revealed the migration of coal particles towards the anode and the structural formation of coal particle chains. The electrorheological behaviour of concentrated coal-water suspensions is examined with the use of a modified coaxial rheometer. The coal fines (d{sub 50}=17.7{mu}m) used in all experiments were produced by milling a low rank bituminous black coal which was followed by a sieving process that eliminated coal particles that were greater than 75{mu}m in size.

  16. Relative influences of solution composition and presence of intracrystalline proteins on magnesium incorporation in calcium carbonate minerals: Insight into vital effects

    NASA Astrophysics Data System (ADS)

    Hermans, Julie; André, Luc; Navez, Jacques; Pernet, Philippe; Dubois, Philippe

    2011-03-01

    Biogenic calcites may contain considerable magnesium concentrations, significantly higher than those observed in inorganic calcites. Control of ion concentrations in the calcifying space by transport systems and properties of the organic matrix of mineralization are probably involved in the incorporation of high magnesium quantities in biogenic calcites, but their relative effects have never been quantified. In vitro precipitation experiments performed at different Mg/Ca ratios in the solution and in the presence of soluble organic matrix macromolecules (SOM) extracted from sea urchin tests and spines showed that, at a constant temperature, magnesium incorporation in the precipitated minerals was mainly dependent on the Mg/Ca ratio of the solution. However, a significant increase in magnesium incorporation was observed in the presence of SOM compared with control experiments. Furthermore, this effect was more pronounced with SOM extracted from the test, which was richer in magnesium than the spines. According to SEM observations, amorphous calcium carbonate was precipitated at high Mg/Casolution. The observed predominant effect of Mg/Casolution, probably mediated in vivo by ion transport to and from the calcifying space, was suggested to induce and stabilize a transient magnesium-rich amorphous phase essential to the formation of high magnesium calcites. Aspartic acid rich proteins, shown to be more abundant in the test than in the spine matrix, further stabilize this amorphous phase. The involvement of the organic matrix in this process can explain the observation that sympatric organisms or even different skeletal elements of the same individual present different skeletal magnesium concentrations.

  17. Remarkable electrokinetic features of charge-stratified soft nanoparticles: mobility reversal in monovalent aqueous electrolyte.

    PubMed

    Moussa, Mariam; Caillet, Céline; Town, Raewyn M; Duval, Jérôme F L

    2015-05-26

    The electrokinetic behavior of G6.5 carboxylate-terminated poly(amidoamine) (PAMAM) starburst dendrimers (8 ± 1 nm diameter) is investigated over a broad range of pH values (3-9) and NaNO3 concentrations (c(? )= 2-200 mM). The dependence of nanodendrimer electrophoretic mobility ? on pH and c(?) is marked by an unconventional decrease of the point of zero mobility (PZM) from 5.4 to 5.5 to 3.8 upon increase in salt concentration, with PZM defined as the pH value at which a reversal of the mobility sign is reached. The existence of a common intersection point is further evidenced for series of mobility versus pH curves measured at different NaNO3 concentrations. Using soft particle electrokinetic theory, this remarkable behavior is shown to originate from the zwitterionic functionality of the PAMAM-COOH particles. The dependence of PZM on c(?) results from the coupling between electroosmotic flow and dendrimeric interphase defined by a nonuniform distribution of amine and carboxylic functional groups. In turn, ? reflects the sign and distribution of particle charges located within an electrokinetically active region, the dimension of which is determined by the Debye length, varied here in the range 0.7-6.8 nm. In agreement with theory, the electrokinetics of smaller G4.5 PAMAM-COOH nanoparticles (5 ± 0.5 nm diameter) further confirms that the PZM is shifted to higher pH with decreasing dendrimer size. Depending on pH, a mobility extremum is obtained under conditions where the Debye length and the particle radius are comparable. This results from changes in particle structure compactness following salt- and pH-mediated modulations of intraparticle Coulombic interactions. The findings solidly evidence the possible occurrence of particle mobility reversal in monovalent salt solution suggested by recent molecular dynamic simulations and anticipated from earlier mean-field electrokinetic theory. PMID:25939023

  18. Effects of Ta incorporation in La{sub 2}O{sub 3} gate dielectric of InGaZnO thin-film transistor

    SciTech Connect

    Qian, L. X.; Lai, P. T., E-mail: laip@eee.hku.hk [Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam Road (Hong Kong); Tang, W. M. [Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong)

    2014-03-24

    The effects of Ta incorporation in La{sub 2}O{sub 3} gate dielectric of amorphous InGaZnO thin-film transistor are investigated. Since the Ta incorporation is found to effectively enhance the moisture resistance of the La{sub 2}O{sub 3} film and thus suppress the formation of La(OH){sub 3}, both the dielectric roughness and trap density at/near the InGaZnO/dielectric interface can be reduced, resulting in a significant improvement in the electrical characteristics of transistor. Among the samples with different Ta contents, the one with a Ta/(Ta?+?La) atomic ratio of 21.7% exhibits the best performance, including high saturation carrier mobility of 23.4?cm{sup 2}/V·s, small subthreshold swing of 0.177?V/dec, and negligible hysteresis. Nevertheless, excessive incorporation of Ta can degrade the device characteristics due to newly generated Ta-related traps.

  19. [Effects of biochar and nitrification inhibitor incorporation on global warming potential of a vegetable field in Nanjing, China].

    PubMed

    Li, Bo; Li, Qiao-Ling; Fan, Chang-Hua; Sun, Li-Ying; Xiong, Zheng-Qin

    2014-09-01

    The influences of biochar and nitrification inhibitor incorporation on global warming potential (GWP) of a vegetable field were studied using the static chamber and gas chromatography method. Compared with the treatments without biochar addition, the annual GWP of N2O and CH4 and vegetable yield were increased by 8.7%-12.4% and 16.1%-52.5%, respectively, whereas the greenhouse gas intensity (GHGI) were decreased by 5.4%-28.7% following biochar amendment. Nitrification inhibitor significantly reduced the N2O emission while had little influence on CH4 emission, decreased GWP by 17.5%-20.6%, increased vegetable yield by 21.2%-40.1%, and decreased the GHGI significantly. The combined application of biochar and nitrification inhibitor significantly increased both vegetable yield and GWP, but to a greater extent for vegetable yield. Therefore, nitrification inhibitor incorporation could be served as an appropriate practice for increasing vegetable yield and mitigating GHG emissions in vegetable field. PMID:25757318

  20. Effects of Ti incorporation on the interface properties and band alignment of HfTaOx thin films on sulfur passivated GaAs

    NASA Astrophysics Data System (ADS)

    Das, T.; Mahata, C.; Maiti, C. K.; Miranda, E.; Sutradhar, G.; Bose, P. K.

    2011-01-01

    Thin HfTaOx and HfTaTiOx gate dielectrics (˜7-8 nm) have been rf sputter-deposited on sulfur passivated GaAs. Our experimental results suggest that the formation of Ga-O at GaAs surface and As diffusion in dielectric may be effectively controlled by Ti incorporation. Possibility of tailoring of band alignment via Ti incorporation is shown. Valence band offsets of 2.6±0.05 and 2.68±0.05 eV and conduction-band offsets of 1.43±0.05 and 1.05±0.05 eV were found for HfTaOx (Eg˜5.45 eV) and HfTaTiOx (Eg˜5.15 eV), respectively.

  1. Incorporation effect of nanosized perovskite LaFe?.?Co?.?O? on the electrochemical activity of Pt nanoparticles-multi walled carbon nanotube composite toward methanol oxidation

    SciTech Connect

    Noroozifar, Meissam, E-mail: mnoroozifar@chem.usb.ac.ir [Department of Chemistry, University of Sistan and Baluchestan, PO Box 98155-147, Zahedan (Iran, Islamic Republic of); Khorasani-Motlagh, Mozhgan; Khaleghian-Moghadam, Roghayeh; Ekrami-Kakhki, Mehri-Saddat; Shahraki, Mohammad [Department of Chemistry, University of Sistan and Baluchestan, PO Box 98155-147, Zahedan (Iran, Islamic Republic of)

    2013-05-01

    Nanosized perovskite LaFe?.?Co?.?O? (LFCO) is synthesized through conventional co-precipitation method and characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) techniques. The incorporation effect of the mentioned perovskite to catalytic activity of the PtNPs-MWCNTs-nafion (or -chitosan) catalyst toward methanol oxidation has been studied by cyclic voltammetry. Based on the electrochemical studies, all MWCNTs-PtNPs-nafion (or chitosan) and MWCNTs-PtNPs-LFCO-nafion (or chitosan) catalysts show a considerable activity for methanol oxidation. However, a synergistic effect is observed when LFCO is added to the catalyst by decreasing the poisoning rate of the Pt catalyst. - Graphical abstract: Nanosized perovskite LaFe?.?Co?.?O? is synthesized and characterized. The incorporation effect of the mentioned perovskite to catalytic activity of the PtNPS-MWCNTs-nafion (or -chitosan) catalyst toward methanol oxidation is studied. Highlights: • Nanocrystalline LaFe?.?Co?.?O? (LFCO) is prepared by a new simple co-precipitation method. • Effect of LFCO to catalytic activity of PtNPS for methanol oxidation is studied. • A synergistic effect is observed when LFCO is added to the Pt catalyst. • Oxygen of LFCO could be considered as active oxygen to remove CO intermediates.

  2. Structural effects on the electrochemical behavior of redox couples incorporated in electrode coatings prepared from copolymers and composites

    SciTech Connect

    Inoue, T.; Anson, F.C.

    1987-01-01

    Five new random vinyl copolymers were prepared and tested as coating materials for binding redox active ions to electrode surfaces. Three of the copolymers were polycationic because of quaternary nitrogen sites. Two uncharged copolymers were used to prepare polycationic coatings by mixing with selected homopolymers, poly(4-vinylpyridine); poly(N-vinyl-2-methylimidazole); poly(4-vinylbenzyldiethylamine), that became polycationic by protonation at the pH where they were employed (4.5). Coatings with the most attractive properties for incorporating and retaining Fe(CN)6(4-) anions were prepared from mixtures of the polycationic copolymers with poly(4-vinylpyridine). The presence of alkyl benzyl either groups in the copolymers was shown to enhance their desirable properties as electrode coatings. Transmission-electron micrographs of coatings revealed some correlation between their internal morphologies and their electrochemical behavior.

  3. Effect of Sn atoms on incorporation of vacancies in epitaxial Ge1-xSnx film grown at low temperature

    NASA Astrophysics Data System (ADS)

    Kamiyama, Eiji; Nakagawa, Satoko; Sueoka, Koji; Ohmura, Takuma; Asano, Takanori; Nakatsuka, Osamu; Taoka, Noriyuki; Zaima, Shigeaki; Izunome, Koji; Kashima, Kazuhiko

    2014-02-01

    The anomalous increase and decrease in the S-parameters of Doppler broadening spectroscopy in positron annihilation spectroscopy in a narrow range of Sn atom content were detected in a Ge1-xSnx thin film grown by MBE at low temperatures. The increase can be explained in terms of vacancies when the target content of 1.7% Sn atoms is incorporated in a Ge matrix, owing to the binding nature between them. However, the S-parameters were markedly decreased when the target content of Sn atoms in the film grown at the same temperature was 0.1%. These changes in the S-parameters correspond to the carrier concentrations obtained by Hall measurements.

  4. Effects of plasma species on the N incorporation of GaAsSbN grown by plasma-assisted gas-source molecular-beam epitaxy

    NASA Astrophysics Data System (ADS)

    Ma, Ta-Chun; Lin, Yan-Ting; Lin, Hao-Hsiung

    2011-03-01

    We report the effects of plasma species on the N incorporation of GaAsSbN. Optical emission spectroscopy and quadruple mass spectroscopy were used to characterize the plasma source. We found a simple correlation between the atomic N species and meta-stable molecular N2* species that is independent of plasma power and N2 flow rate. In order to achieve atomic-N-rich growth conditions, we place a PBN shutter in front of our plasma source, rich in meta-stable N2* molecules, to facilitate the relaxation of N2* and turn the growth condition into an atomic-N-dominant one. When an atomic-N-rich condition is used, N incorporation rate decreases when Sb flux increases and increases as growth temperature increases. This behavior is well explained by a surface kinetics model. When a N2*-rich condition is used, the N incorporation in GaAsSbN is enhanced by increase in Sb flux and growth temperature.

  5. The effects of atmospheric [CO2] on carbon isotope fractionation and magnesium incorporation into biogenic marine calcite

    NASA Technical Reports Server (NTRS)

    Vieira, Veronica

    1997-01-01

    The influences of atmospheric carbon dioxide on the fractionation of carbon isotopes and the magnesium incorporation into biogenic marine calcite were investigated using samples of the calcareous alga Amphiroa and benthic foraminifer Sorites grown in the Biosphere 2 Ocean system under variable atmospheric CO2 concentrations (approximately 500 to 1200 ppm). Carbon isotope fractionation was studied in both the organic matter and the skeletal carbonate. Magnesium analysis was to be performed on the carbonate removed during decalcification. These data have not been collected due to technical problems. Carbon isotope data from Amphiroa yields a linear relation between [CO2] and Delta(sup 13)C(sub Corg)values suggesting that the fractionation of carbon isotopes during photosynthesis is positively correlated with atmospheric [CO2]. [CO2] and Delta(sup 13)C(sub Corg) values for Sorites produce a relation that is best described by a hyperbolic function where Delta(sup 13)C(sub Corg) values increase between 300 and 700 ppm and decrease from 700 to 1200 ppm. Further investigation of this relation and Sorites physiology is needed.

  6. HidSecSOFTSUSY: Incorporating effects from hidden sectors in the numerical computation of the MSSM spectrum

    NASA Astrophysics Data System (ADS)

    Keren-Zur, Boaz

    2011-02-01

    SOFTSUSY is a software designed to solve the RG equations of the MSSM and compute its low energy spectrum. HidSecSOFTSUSY is an extension of the SOFTSUSY package which modifies the beta functions to include contributions from light dynamic fields in the hidden sector. Program summaryProgram title: HidSecSOFTSUSY Catalogue identifier: AEHP_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEHP_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 4167 No. of bytes in distributed program, including test data, etc.: 141 411 Distribution format: tar.gz Programming language: C++, Fortran Computer: Personal computer Operating system: Tested on GNU/Linux Word size: 32 bits Classification: 11.6 External routines: Requires an installed version of SOFTSUSY ( http://projects.hepforge.org/softsusy/) Nature of problem: Calculating supersymmetric particle spectrum and mixing parameters while incorporating dynamic modes from the hidden sector into the renormalization group equations. The solution to the equations must be consistent with a high-scale boundary condition on supersymmetry breaking parameters, as well as a weak-scale boundary condition on gauge couplings, Yukawa couplings and the Higgs potential parameters. Solution method: Nested iterative algorithm. Running time: A few seconds per parameter point.

  7. Palmitoylation of the feline immunodeficiency virus envelope glycoprotein and its effect on fusion activity and envelope incorporation into virions

    SciTech Connect

    Gonzalez, Silvia A.; Paladino, Monica G. [Laboratorio de Virologia, CONICET-Universidad de Belgrano (UB), Villanueva 1324 (C1426BMJ), Buenos Aires (Argentina)] [Laboratorio de Virologia, CONICET-Universidad de Belgrano (UB), Villanueva 1324 (C1426BMJ), Buenos Aires (Argentina); Affranchino, Jose L., E-mail: jose.affranchino@comunidad.ub.edu.ar [Laboratorio de Virologia, CONICET-Universidad de Belgrano (UB), Villanueva 1324 (C1426BMJ), Buenos Aires (Argentina)

    2012-06-20

    The feline immunodeficiency virus (FIV) envelope glycoprotein (Env) possesses a short cytoplasmic domain of 53 amino acids containing four highly conserved cysteines at Env positions 804, 811, 815 and 848. Since palmitoylation of transmembrane proteins occurs at or near the membrane anchor, we investigated whether cysteines 804, 811 and 815 are acylated and analyzed the relevance of these residues for Env functions. Replacement of cysteines 804, 811 and 815 individually or in combination by serine residues resulted in Env glycoproteins that were efficiently expressed and processed. However, mutations C804S and C811S reduced Env fusogenicity by 93% and 84%, respectively, compared with wild-type Env. By contrast, mutant C815S exhibited a fusogenic capacity representing 50% of the wild-type value. Remarkably, the double mutation C804S/C811S abrogated both Env fusion activity and Env incorporation into virions. Finally, by means of Click chemistry assays we demonstrated that the four FIV Env cytoplasmic cysteines are palmitoylated.

  8. A comparative analysis of XV-15 tiltrotor hover test data and WOPWOP predictions incorporating the fountain effect

    NASA Technical Reports Server (NTRS)

    Rutledge, Charles K.; Coffen, Charles D.; George, Albert R.

    1991-01-01

    Acoustic measurements from a hovering full scale XV-15 tilt rotor with the advanced technology blades are presented which show the directionality of fountain effect noise. Predicted acoustic directivity results are also presented which show agreement with the measured data. The aeroacoustic code, WOPWOP, was used in conjunction with a mathematical model which simulated the fountain recirculation aerodynamic effect on the rotor blade surface pressures. The predictions were used to identify the spike character in the measured data as fountain effect associated noise. The directivity of the fountain effect noise was observed to be dominant at the rear of the aircraft with increased intensities 45 degrees below the rotor disk planes.

  9. The capture and destruction of chlorinated solvents via electrokinetic pumping: The LASAGNA{trademark} process

    SciTech Connect

    Salvo, J.J. [GE Corporate Research and Development, Schenectady, NY (United States); Ho, S.V. [Monsanto Company, St. Louis, MO (United States); Shoemaker, S.H. [DuPont Engineering, Houston, TX (United States)

    1995-12-31

    Remediating soils and groundwater that have been contaminated with chlorinated solvents is a significant challenge for current environmental technology. Soils with a high proportion of fine silts and clays have been especially recalcitrant due to their low permeability. Recently, electrokinetics has shown great promise in gaining access to these contaminated zones that fail to yield with traditional pumping methods. An integrated approach using electrokinetics combined with in situ capture and destruction zones (LASAGNA{sup trademark}) is being developed and field tested by Monsanto, DuPont and GE under the auspices of the EPA`s Remediation Technology Development Forum and with financial support from the Department of Energy. To speed implementation and encourage partnering, royalty-free cross-licensing of the developed technology is available to consortium members for use on their sites.

  10. Field Testing of Rapid Electrokinetic Nanoparticle Treatment for Corrosion Control of Steel in Concrete

    NASA Technical Reports Server (NTRS)

    Cardenas, Henry E.; Alexander, Joshua B.; Kupwade-Patil,Kunal; Calle, Luz Marina

    2009-01-01

    This work field tested the use of electrokinetics for delivery of concrete sealing nanoparticles concurrent with the extraction of chlorides. Several cylinders of concrete were batched and placed in immersion at the Kennedy Space Center Beach Corrosion Test Site. The specimens were batched with steel reinforcement and a 4.5 wt.% (weight percent) content of sodium chloride. Upon arrival at Kennedy Space Center, the specimens were placed in the saltwater immersion pool at the Beach Corrosion Test Site. Following 30 days of saltwater exposure, the specimens were subjected to rapid chloride extraction concurrent with electrokinetic nanoparticle treatment. The treatments were operated at up to eight times the typical current density in order to complete the treatment in 7 days. The findings indicated that the short-term corrosion resistance of the concrete specimens was significantly enhanced as was the strength of the concrete.

  11. Electrokinetic remediation of inorganic and organic pollutants in textile effluent contaminated agricultural soil.

    PubMed

    Annamalai, Sivasankar; Santhanam, Manikandan; Sundaram, Maruthamuthu; Curras, Marta Pazos

    2014-12-01

    The discharge from the dyeing industries constitutes unfixed dyes, inorganic salts, heavy metal complexes etc., which spoil the surrounding areas of industrial sites. The present article reports the use of direct current electrokinetic technique for the treatment of textile contaminated soil. Impressed direct current voltage of 20 V facilitates the dye/metal ions movement in the naturally available dye contaminated soil towards the opposite electrode by electromigration. IrO2–RuO2–TiO2/Ti was used as anode and Ti used as cathode. UV–Visible spectrum reveals that higher dye intensity was nearer to the anode. Ni, Cr and Pb migration towards the cathode and migration of Cu, SO42? and Cl? towards anode were noticed. Chemical oxygen demand in soil significantly decreased upon employing electrokinetic. This technology may be exploited for faster and eco-friendly removal of dye in soil environment. PMID:25461934

  12. Capillary electrokinetic separations with optical detection. Technical progress report, February 1, 1993--January 31, 1996

    SciTech Connect

    Sepaniak, M.J.

    1998-02-01

    The seminal work of Jorgenson in 1981 ushered in the modern era of capillary electrophoresis (CE). Since that time, research activities involving capillary electrokinetic methods of separation have grown exponentially. Numerous conferences, symposia, monographs, and dedicated journals attest to the maturing of these techniques. While many of the obvious approaches have been explored, and instrumentation is reasonably well-developed, the full potential of CE has clearly not yet been reached. Moreover, CE techniques are not universally accepted as desirable alternatives to traditional chromatographic and electrophoretic methods of separation. Thus, it is likely that research into various aspects of capillary electrokinetic separations will continue at a torrid pace for at least the remainder of this decade.

  13. Ripple structure-generated hybrid electrokinetics for on-chip mixing and separating of functionalized beads.

    PubMed

    Cheng, I-Fang; Chiang, Sheng-Chuan; Chung, Cheng-Che; Yeh, Trai-Ming; Chang, Hsien-Chang

    2014-11-01

    We present an electrokinetics-based microfluidic platform that is capable of on-chip manipulating, mixing, and separating microparticles through adjusting the interrelated magnitudes of dielectrophoresis and AC electroosmosis. Hybrid electrokinetic phenomenon is generated from an electric field-induced micro-ripple structure made of ultraviolet-curable glue. Size-dependent particle separation and selective removal over the ripple structure is demonstrated successfully. Varying the waveform from sine-wave to square-wave allows generating a fluid convection at specific positions to mix the antibody-functionalized beads and antigen. Potential application in the bead-based immunoassay was also demonstrated for immuno-reaction and subsequently separating the bead-bead aggregate and non-binding beads on-chip. PMID:25610512

  14. Research and experimental testing of a new kind electrokinetic logging tool

    NASA Astrophysics Data System (ADS)

    Li, Feng-Bo; Ju, Xiao-Dong; Qiao, Wen-Xiao; Lu, Jun-Qiang; Men, Bai-Rong

    2014-12-01

    We designed a new downhole electrokinetic logging tool based on numerical simulations and petrophysical experiments. Acoustic and electric receivers cannot be arranged at the same depth, and the proposed composite electrokinetic logging tool offers a solution to this problem. The sound field characteristics of the detectors were tested in a water tank in the laboratory. Then, we calculated the sound pressure of the radiated acoustic field and the transmitting voltage response of the transmitting transducers; in addition, we analyzed the directivity and application of the acoustic transmitting probe based on linear phased array. The results suggest that the sound pressure generated at 1500 mm spacing reaches up to 47.2 kPa and decreases with increasing acoustic source frequency. When the excitation signals delay time of adjacent acoustic transmitting subarrays increases, the radiation beam of the main lobe is deflected and its energy gradually increases, which presumably enhances the acoustoelectric conversion efficiency.

  15. A modeling and simulation framework for electrokinetic nanoparticle treatment

    NASA Astrophysics Data System (ADS)

    Phillips, James

    2011-12-01

    The focus of this research is to model and provide a simulation framework for the packing of differently sized spheres within a hard boundary. The novel contributions of this dissertation are the cylinders of influence (COI) method and sectoring method implementations. The impetus for this research stems from modeling electrokinetic nanoparticle (EN) treatment, which packs concrete pores with differently sized nanoparticles. We show an improved speed of the simulation compared to previously published results of EN treatment simulation while obtaining similar porosity reduction results. We mainly focused on readily, commercially available particle sizes of 2 nm and 20 nm particles, but have the capability to model other sizes. Our simulation has graphical capabilities and can provide additional data unobtainable from physical experimentation. The data collected has a median of 0.5750 and a mean of 0.5504. The standard error is 0.0054 at alpha = 0.05 for a 95% confidence interval of 0.5504 +/- 0.0054. The simulation has produced maximum packing densities of 65% and minimum packing densities of 34%. Simulation data are analyzed using linear regression via the R statistical language to obtain two equations: one that describes porosity reduction based on all cylinder and particle characteristics, and another that focuses on describing porosity reduction based on cylinder diameter for 2 and 20 nm particles into pores of 100 nm height. Simulation results are similar to most physical results obtained from MIP and WLR. Some MIP results do not fall within the simulation limits; however, this is expected as MIP has been documented to be an inaccurate measure of pore distribution and porosity of concrete. Despite the disagreement between WLR and MIP, there is a trend that porosity reduction is higher two inches from the rebar as compared to the rebar-concrete interface. The simulation also detects a higher porosity reduction further from the rebar. This may be due to particles aggregating before reaching the rebar that can easily be seen in the graphical representation of the simulation cylinders. The dissertation author has created a web based framework to allow an interdisciplinary team to work in concert with access to the simulation and the results generated. The results are stored into a MySQL database. The database currently holds 271 simulation runs. Simulation requests can be entered into a web interface and will automatically be processed in the order entered and the results stored into the database. Results can also be retrieved from the database and filtered based on any simulation parameter. Statistical analysis can be completed on the data points stored in the database by using version of Rweb modified by the dissertation author. The result is a collaborative framework that can be extended to address future investigations into pore packing and chloride blocking.

  16. Incorporating the effects of topographic amplification in the analysis of earthquake-induced landslide hazards using logistic regression

    Microsoft Academic Search

    S. T. Lee; T. T. Yu; W. F. Peng; C. L. Wang

    2010-01-01

    Seismic-induced landslide hazards are studied using seismic shaking intensity based on the topographic amplification effect. The estimation of the topographic effect includes the theoretical topographic amplification factors and the corresponding amplified ground motion. Digital elevation models (DEM) with a 5-m grid space are used. The logistic regression model and the geographic information system (GIS) are used to perform the seismic

  17. Electrokinetic phosphorus recovery from packed beds of sewage sludge ash: yield and energy demand

    Microsoft Academic Search

    Georg Sturm; Harald Weigand; Clemens Marb; Wilfried Weiß; Bernd Huwe

    2010-01-01

    The static lifetime of primary phosphate stocks is estimated as one century. Thus, the exploitation of secondary phosphorus\\u000a sources becomes increasingly important. This study focussed on the feasibility of an electrokinetic phosphorus recovery from\\u000a sewage sludge ash (P-content ~5 wt%). Packed bed experiments were conducted under varied electric conditions with and without\\u000a acid pre-treatment and employing porous and ion exchange materials

  18. Polymer depressants at the talc–water interface: adsorption isotherm, microflotation and electrokinetic studies

    Microsoft Academic Search

    Gayle E Morris; Daniel Fornasiero; John Ralston

    2002-01-01

    The behaviour of polymer depressants at the talc–water interface was investigated as a function of ionic strength and pH. Adsorption isotherms, microflotation and electrokinetic studies were used to examine the surface interactions involved. The polymers examined were carboxymethyl cellulose (CMC) and two synthetic polyacrylamides (PAM-A and PAM-N).The adsorption of the two anionic polymers, CMC and PAM-A, on talc, and hence,

  19. Permeability prediction from MICP and NMR data using an electrokinetic approach

    Microsoft Academic Search

    P. W. J. Glover; I. I. Zadjali; K. A. Frew

    2006-01-01

    Theaccuratemodelingofoil,gas,andwaterreservoirsde- pendsfundamentallyuponaccesstoreliablerockpermeabil- itiesthatcannotbeobtaineddirectlyfromdownholelogs.In- stead, a range of empirical models are usually employed.We propose a new model that has been derived analytically from electrokinetic theory and is equally valid for all lithologies. The predictions of the new model and four other common models Kozeny-Carman, Berg, Swanson, and van Baaren have been compared using measurements carried out on fusedandunfusedglassbeadpacksaswellason91rocksam- ples representing 11

  20. Removal of lead from a silt loam soil by electrokinetic remediation

    Microsoft Academic Search

    Gordon C. C Yang; Shuen-Long Lin

    1998-01-01

    In this study, a silt loam soil spiked with lead (ca. 1000 mg\\/kg) was treated by electrokinetics using an electric gradient of 1 V\\/cm. In all tests, 0.1 M acetic acid was used as the cathode reservoir fluid. However, anode reservoir fluids used were 0.1 M of acetic acid, citric acid, ethylenediaminetetraacetic acid (EDTA), respectively. Experimental results have shown that

  1. Chemical conditioning of electrode reservoirs during electrokinetic soil flushing of Pb-contaminated silt loam

    Microsoft Academic Search

    Brian E. Reed; Mitchell T. Berg; J. H. Hatfield; J. C. Thompson

    1995-01-01

    The in-situ remediation of a lead-contaminated soil (silt loam, K{sub H} = 5 à 10⁻⁸ cm\\/s, soil Pb = 1,000 mg\\/kg) by electrokinetic (EK) soil flushing [60 V (DC)] was studied. Research focused on the chemical conditioning of the electrode reservoirs with either 500 μS\\/cm (as NaNOâ, baseline behavior), acetic acid (HAc), HCl, or EDTA. For baseline tests there were

  2. Composable Behavioral Models and Schematic-Based Simulation of Electrokinetic Lab-on-a-Chip Systems

    Microsoft Academic Search

    Yi Wang; Qiao Lin; Tamal Mukherjee

    2006-01-01

    This paper presents composable behavioral models and a schematic-based simulation methodology to enable top-down design of electrokinetic (EK) lab-on-a-chip (LoC). Complex EK LoCs are shown to be decomposable into a system of elements with simple geometry and specific function. Parameterized and analytical models are developed to describe the electric and biofluidic behavior within each element. Electric and biofluidic pins at

  3. Numerical analysis of electrokinetic transport in micro-nanofluidic interconnect preconcentrator in hydrodynamic flow

    Microsoft Academic Search

    Yi Wang; Kapil Pant; Zhijian Chen; Guiren Wang; William F. Diffey; Paul Ashley; Shivshankar Sundaram

    2009-01-01

    The phenomenon of enrichment of charged analytes due to the presence of an electric field barrier at the micro-nanofluidic\\u000a interconnect can be harnessed to enhance sensitivity and limit-of-detection in sensor instruments. We present a numerical\\u000a analysis framework to investigate two critical electrokinetic phenomena underlying the experimental observation in Plecis\\u000a et al. (Micro Total Analysis Systems, pp 1038–1041, 2005b): (1) ion

  4. Simultaneous determination of ingredients in a cold medicine by cyclodextrin-modified microemulsion electrokinetic chromatography

    Microsoft Academic Search

    Hitoshi Okamoto; Toshiaki Nakajima; Yuji Ito; Takao Aketo; Kenji Shimada; Susumu Yamato

    2005-01-01

    Cyclodextrin-modified microemulsion electrokinetic chromatography (CD-MEEKC) was used to simultaneously determine 14 active ingredients (thiamine nitrate, anhydrous caffeine, acetaminophen, riboflavin, guaifenesin, pseudoephedrine hydrochloride, ascorbic acid, ethenzamide, DL-methylephedrine hydrochloride, dihydrocodeine phosphate, ibuprofen, noscapine, carbinoxamine maleate, and bromhexine hydrochloride) in a cold medicine. Separation of the ingredients was optimized by changing the SDS concentration and oil type and the addition of 2-propanol and

  5. Interactions between local anesthetics and lipid dispersions studied with liposome electrokinetic capillary chromatography

    Microsoft Academic Search

    Jaana Muhonen; Juha M. Holopainen; Susanne K. Wiedmer

    2009-01-01

    In the case of local anesthetic intoxication, intravenous administration of lipid-based Intralipid dispersion (Fresenius Kabi) can be used for the entrapment of hydrophobic drugs. Our long-term aim is to develop a sensitive, efficient, and non-harmful lipid-based formulation to specifically trap harmful substances. In this study liposome electrokinetic capillary chromatography (LEKC) was used to study the interactions between local anesthetics and

  6. Forsterite surface composition in aqueous solutions: a combined potentiometric, electrokinetic, and spectroscopic approach

    Microsoft Academic Search

    Oleg S. Pokrovsky; Jacques Schott

    2000-01-01

    Surfaces of natural and synthetic forsterite (Fo91 and Fo100) in aqueous solutions at 25°C were investigated using surface titrations in batch and limited residence time reactors, column filtration experiments, electrokinetic measurements (streaming potential and electrophoresis techniques), Diffuse Reflectance Infrared Spectroscopy (DRIFT), and X-ray Photoelectron Spectroscopy (XPS). At pH < 9, a Mg-depleted, Si-rich layer (<20 Å thick) is formed on

  7. Determination of Flavonoids from Paulownia tomentosa (Thunb) Steud by Micellar Electrokinetic Capillary Electrophoresis

    Microsoft Academic Search

    Ting-Fu Jiang; Xin Du; Yan-Ping Shi

    2004-01-01

    A micellar electrokinetic capillary electrophoresis (MEKC) method was developed for the determination of three flavonoids: diplacone (DI), mimulone (MI) and apigenin (AP) in the flowers of Paulownia tomentosa(Thunb) Steud. A buffer solution (pH 10.00) of 20 mM sodium borate, 10 mM sodium dodecyl sulfate (SDS) and 5% methanol was found to be the most suitable electrolyte for this separation. Regression

  8. Determination of hydrocortisone, polymyxin B and Zn-bacitracin in pharmaceutical preparations by micellar electrokinetic chromatography

    Microsoft Academic Search

    J. M. Lemus Gallego; J. Pérez Arroyo

    2003-01-01

    A new, simple and accurate micellar electrokinetic chromatography (MEKC) method is established for quantification of hydrocortisone, polymyxin B and Zn-bacitracin in local pharmaceutical preparations. The separation was carried out at 25 °C and 25 kV, using a 15 mmol Lу phosphate-15 mmol Lу borate buffer (pH 8.2), 60 mmol Lу sodium dodecylsulfate (SDS), and 10% methanol-water (v\\/v) as background electrolyte.

  9. Structural selectivity provided by starburst dendrimers as pseudostationary phase in electrokinetic chromatography

    Microsoft Academic Search

    Nobuo Tanaka; Takeshi Fukutome; Tetsuya Tanigawa; Ken Hosoya; Kazuhiro Kimata; Takeo Araki; Klaus K. Unger

    1995-01-01

    Starburst dendrimers (SBDs) were used as a pseudostationary phase in electrokinetic chromatography (EKC) of hydrophobic compounds. The selectivity of SBD-mediated EKC (SBD-EKC) was different from those in micellar EKC (MEKC) systems, in spite of the apparent structural resemblance between micelles and SBDs. The SBDs provided similar selectivity as polymer gel packing materials in reversed-phase liquid chromatography (RPLC), showing little selectivity

  10. Liposome electrokinetic chromatography based in vitro model for early screening of the drug-induced phospholipidosis risk.

    PubMed

    Wang, Tingting; Feng, Ying; Jin, Xiaohan; Fan, Xuxin; Crommen, Jacques; Jiang, Zhengjin

    2014-08-01

    Drug-induced phospholipidosis (PLD) is a storage disorder of lysosomes characterized by the excessive accumulation of phospholipids as a result of improper medical treatments. Although few evidences have supported that PLD can induce significant pathological consequences, this potential toxicity indeed can put off the drug discovery process. In this research, a high-throughput liposome electrokinetic chromatography (LEKC) method was validated to evaluate the PLD risk of drug candidates by screening drug-phospholipid interaction, which correlates to the phospholipidosis inducing risk. A statistical analysis based on the Spearman's correlation test showed that the retention factors (log k) of the tested drugs in the LEKC system and the literature reported in vivo and in vitro PLD data were highly correlated. In order to investigate the predictability of LEKC, the effect of liposome composition such as the molar ratio of phospholipids and the addition of cholesterol were also discussed in this study. The results indicated that the LEKC method could offer a fast, reliable and cost-effective screening tool for early prediction of the PLD inducing potential of drug candidates. PMID:24814828

  11. Influence of soluble copper on the electrokinetic properties and transport of copper oxychloride-based fungicide particles

    NASA Astrophysics Data System (ADS)

    Paradelo, Marcos; Letzner, Adrian; Arias-Estévez, Manuel; Garrido-Rodríguez, Beatriz; López-Periago, J. Eugenio

    2011-09-01

    This article describes the influence of dissolved copper on the electrokinetic properties and transport of a copper oxychloride-based fungicide (COF) in porous media. The Zeta potential (?) of COF particles increases (viz. becomes less negative) with increasing concentration of Cu 2+ in the bulk solution. ? decreases for COF when the electrolyte (NaNO 3) concentration is raised from 1 to 10 mM. This can be ascribed to ion correlation of Cu 2+ in the electrical double layer (EDL). COF transport tests in quartz sand columns showed the addition of Cu 2+ to the bulk solution to result in increased retention of the metal. Modelling particle deposition dynamics provided results consistent with kinetic attachment. Based on the effect of soluble Cu on colloid mobility, the transport of particulate and soluble forms of copper is coupled via the chemistry of pore water and colloid interactions. Mutual effects between cations and colloids should thus be considered when determining the environmental fate of particulate and soluble forms of copper in soil and groundwater (especially at copper-contaminated sites).

  12. IMMUNOSTIMULATING COMPLEXES INCORPORATING E. TENELLA ANTIGENS AND PLANT SAPONINS AS AN EFFECTIVE DELIVERY SYSTEM FOR COCCIDIA VACCINE IMMUNIZATION.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Immunostimulating complexes (ISCOMs) are a unique, multimolecular structure formed by encapsulating antigens, lipids and triterpene saponins of plant origin and are an effective delivery system for various kinds of antigens. The uses of ISCOMs formulated with saponins from plants native to Kazakhs...

  13. A Magnetic Circuit Model for an IPM Synchronous Machine Incorporating Moving Airgap and Cross-Coupled Saturation Effects

    Microsoft Academic Search

    Seok-Hee Han; T. M. Jahns; W. L. Soong

    2007-01-01

    A new magnetic circuit model is presented for an interior permanent magnet (IPM) synchronous machine, using a machine with three-phase distributed stator windings and three layers of flux barriers in the rotor as an example topology. The model accounts for: i) the effects of cross-coupled magnetic saturation caused by the salient rotor; ii) variation of magnetic saturation levels in the

  14. The effect of aromatase inhibitor letrozole incorporated in gonadotrophin-releasing hormone antagonist multiple dose protocol in poor responders undergoing in vitro fertilization

    PubMed Central

    Lee, Kyung-Hee; Suk, Hye-Jin; Lee, You-Jeong; Kwon, Su-Kyung; Kim, Sung-Hoon; Chae, Hee-Dong; Kang, Byung-Moon

    2014-01-01

    Objective To evaluate whether letrozole incorporated in a gonadotrophin-releasing hormone (GnRH) antagonist multiple dose protocol (MDP) improved controlled ovarian stimulation (COS) and in vitro fertilization (IVF) results in poor responders who underwent IVF treatment. Methods In this retrospective cohort study, a total of 103 consecutive IVF cycles that were performed during either the letrozole/GnRH antagonist MDP cycles (letrozole group, n=46) or the standard GnRH antagonist MDP cycles (control group, n=57) were included in 103 poor responders. COS results and IVF outcomes were compared between the two groups. Results Total dose and days of recombinant human follicle stimulating hormone (rhFSH) administered were significantly fewer in the letrozole group than in the control group. Duration of GnRH antagonist administered was also shorter in the letrozole group. The number of oocytes retrieved was significantly higher in the letrozole group. However, clinical pregnancy rate per cycle initiated, clinical pregnancy rate per embryo transfer, embryo implantation rate and miscarriage rate were similar in the two groups. Conclusion The letrozole incorporated in GnRH antagonist MDP may be more effective because it results comparable pregnancy outcomes with shorter duration and smaller dose of rhFSH, when compared with the standard GnRH antagonist MDP. PMID:24883293

  15. The effects of curing medium on flexural strength and water permeability of concrete incorporating TiO 2 nanoparticles

    Microsoft Academic Search

    Ali Nazari

    2011-01-01

    The effect of limewater on flexural strength and water permeability of TiO2 nanoparticles binary blended concrete has been investigated. TiO2 nanoparticles with partial replacement of cement by 0.5, 1.0, 1.5 and 2.0 weight percent have been used as reinforcement.\\u000a Curing of the specimens has been carried out in water and saturated limewater for 7, 28 and 90 days after casting. The

  16. Structure of Multiresponsive Brush-Decorated Nanoparticles: A Combined Electrokinetic, DLS, and SANS Study.

    PubMed

    Martin, Jennifer R S; Bihannic, Isabelle; Santos, Catarina; Farinha, José Paulo S; Demé, Bruno; Leermakers, Frans A M; Pinheiro, José P; Rotureau, Elise; Duval, Jérôme F L

    2015-04-28

    Particles consisting of a glassy poly(methyl methacrylate) core (ca. 40 nm in radius) decorated with a poly(N-isopropylacrylamide) anionic corona are synthesized using either methacrylic acid (MA) or acrylic acid (AA) as reactive comonomers in the shell. The different reactivity ratios of MA and AA toward N-isopropylacrylamide originates p(MA-N) and p(N-AA) particles with carboxylate charges supposedly located, preferentially, in the close vicinity of the core and at the shell periphery, respectively. The corresponding swelling features of these nanoparticles are addressed over a broad range of pH values (4 to 7.5), NaNO3 concentrations (3 to 200 mM), and temperatures (15 to 45 °C) by dynamic light scattering (DLS) and small angle neutron scattering (SANS). DLS shows that the swelling of the particle shells increases their thickness from ?10 to 90 nm with decreasing temperature, ionic strength, or increasing pH, with the effect being more pronounced for p(N-AA) whose lower critical solution temperature is shifted to higher values compared to that of p(MA-N). Potentiometric titration and electrokinetic results further reflect the easier dissociation of carboxyl groups in p(N-AA) and a marked heterogeneous interfacial swelling of the latter with decreasing solution salt content. The DLS response of both particles is attributed to the multiresponsive nature of a peripheral dilute shell, while SANS only probes the presence of a quasi-solvent-free dense polymer layer, condensed on the core surface. The thickness of that layer slightly increases from ?6 to 9.5 nm with increasing temperature from 15 to 45 °C (at 15 mM NaNO3 and pH 5) due to the collapse of the outer dilute shell layer. Overall, results evidence a nonideal brush behavior of p(MA-N) and p(N-AA) and their microphase segregated shell structure, which supports some of the conclusions recently formulated from approximate self-consistent mean-field computations. PMID:25840116

  17. Incorporating the productivity benefits into the assessment of cost effective energy savings potential using conservation supply curves

    SciTech Connect

    Laitner, John A.; Ruth, Michael; Worrell, Ernst

    2001-07-24

    We review the relationship between energy efficiency improvement measures and productivity in industry. We propose a method to include productivity benefits in the economic assessment of the potential for energy efficiency improvement. The paper explores the implications of how this change in perspective might affect the evaluation of energy-efficient technologies for a study of the iron and steel industry in the U.S. It is found that including productivity benefits explicitly in the modeling parameters would double the cost-effective potential for energy efficiency improvement, compared to an analysis excluding those benefits. We provide suggestions for future research for this important area.

  18. Green methodology based on dispersive liquid-liquid microextraction and micellar electrokinetic chromatography for 5-nitroimidazole analysis in water samples.

    PubMed

    Hernández-Mesa, Maykel; Cruces-Blanco, Carmen; García-Campaña, Ana M

    2013-09-01

    Dispersive liquid-liquid microextraction has been proposed as an extraction technique combined with micellar electrokinetic chromatography (MEKC) for the analysis of eight 5-nitroimidazole compounds, including some metabolites, in water samples. Determination has been carried out using a diode array detector, employing 20 mM sodium phosphate and 150 mM SDS as separation buffer. Separation has taken place under a voltage of 25 kV and a temperature of 20°C. Samples were prepared in a buffer without micelles and they were hydrodynamically injected at 50 mbar for 25 s, producing a sweeping effect on the analytes for increasing sensitivity. Different factors involved in the dispersive liquid-liquid microextraction procedure were optimized, such as sample pH, nature, and volume of extraction and dispersive solvents in the mixture, percentage of NaCl added to sample and shaking time after the injection of the extraction and dispersive solvents. The method was characterized for water samples, achieving detection limits lower than 2.4 ?g/L. Trueness was checked in river, tap, and bottled water. Dispersive liquid-liquid microextraction combined with MEKC constitutes an easy, cheap, and green alternative for 5-nitroimidazole analysis in environmental water samples. PMID:23857677

  19. Stability-indicating micellar electrokinetic chromatography technique for simultaneous measurement of delapril and manidipine from a combination drug formulation.

    PubMed

    Todeschini, Vítor; Sangoi, Maximiliano da Silva; Meira, Alianise da Silva; Miron, Diogo; Lange, Alini Dall Cortivo; Volpato, Nadia Maria

    2014-01-01

    A stability-indicating micellar electrokinetic chromatography (MEKC) method was developed and validated for simultaneous analysis of delapril (DEL) and manidipine (MAN) using salicylic acid as an internal standard. The MEKC method was performed using a fused-silica capillary (effective length of 72 cm) with 50 mM of borate buffer and 5 mM of anionic surfactant sodium dodecylsulfate at pH 9.0 as the background electrolyte. The separation was achieved at 25 kV applied voltage and 35 degrees C. The injection was performed at 50 mbar for 5 s, with detection at 208 nm. The method was linear in the range of 15-150 microg/mL (r2 = 0.9966) for DEL and 5-50 microg/mL (r2 = 0.9985) for MAN with adequate results for the precision (< or = 1.87%) and accuracy (98.94% for DEL and 100.65% for MAN). The specificity of the method and its stability-indicating capability was demonstrated through forced degradation studies, which showed that there was no interference from the excipients. The Plackett-Burman experimental design was used for robustness evaluation, giving results within the acceptable range. The method was successfully applied for analysis of the drugs, and the results were compared to an LC method, resulting in nonsignificant differences (P = 0.78 and 0.84 for DEL and MAN, respectively). PMID:24672867

  20. Biological permeable reactive barriers coupled with electrokinetic soil flushing for the treatment of diesel-polluted clay soil.

    PubMed

    Mena, Esperanza; Ruiz, Clara; Villaseñor, José; Rodrigo, Manuel A; Cañizares, Pablo

    2015-02-11

    Removal of diesel from spiked kaolin has been studied in the laboratory using coupled electrokinetic soil flushing (EKSF) and bioremediation through an innovative biological permeable reactive barriers (Bio-PRBs) positioned between electrode wells. The results show that this technology is efficient in the removal of pollutants and allows the soil to maintain the appropriate conditions for microorganism growth in terms of pH, temperature, and nutrients. At the same time, EKSF was demonstrated to be a very interesting technology for transporting pollutants, microorganisms and nutrients, although results indicate that careful management is necessary to avoid the depletion of nutrients, which are effectively transported by electro-migration. After two weeks of operation, 30% of pollutants are removed and energy consumption is under 70 kWh m(-3). Main fluxes (electroosmosis and evaporation) and changes in the most relevant parameters (nutrients, diesel, microorganisms, surfactants, moisture conductivity and pH) during treatment and in a complete post-study analysis are studied to give a comprehensive description of the most relevant processes occurring in the soil (pollutant transport and biodegradation). PMID:25262485

  1. Cyclodextrin-modified micellar electrokinetic capillary chromatography separations of benzopyrene isomers. Correlation with computationally derived host-guest energies

    SciTech Connect

    Copper, C.L.; Sepaniak, M.J. (Univ. of Tennessee, Knoxville, TN (United States))

    1994-01-01

    General adjustment of system retention is often inadequate to resolve structurally similar compounds in micellar electrokinetic capillary chromatography (MECC). The use of cyclodextrins (CDs) as mobile-phase additives is described for separations of structural isomers. CDs are shown to provide dramatic and selective effects on the retention of benzopyrene isomers. Efficient separations of six methyl-substituted and three 1-position-substituted benzopyrene isomers are presented. Derivatized [gamma]-CD discriminates between substitutional isomers less than native [gamma]-CD. A comparison of sodium dodecylsulfate (SDS) and sodium cholate (NaC) surfactant systems indicates that SDS-CD mobile phases are more favorable for separation of benzopyrene isomers. Possible separation mechanisms are discussed and evaluated based on results of these studies. The computational procedures of a commercial molecular modeling system are modified and used to determine interaction energies for various host-guest (i.e., [gamma]-CD-benzopyrene) combinations. By use of the average of the five best energy values from interaction energy matrices, correct elution order is predicted for the 1-position-substituted and most of the methyl-substituted benzopyrene isomers. Consideration of different possible CD-benzopyrene orientations must be made to correctly predict elution order. Inspection of the interaction energy matrices revealed no obvious energy barriers that would inhibit inclusion complex formation. 28 refs., 4 figs., 2 tabs.

  2. Microemulsion electrokinetic chromatography: an application for the simultaneous determination of suspected fragrance allergens in rinse-off products.

    PubMed

    Furlanetto, Sandra; Orlandini, Serena; Giannini, Iacopo; Pasquini, Benedetta; Pinzauti, Sergio

    2010-11-15

    A mixture of 18 neutral UV-active compounds with different characteristics of polarity was determined by capillary electrophoresis using a pseudostationary phase constituted by a microemulsion. The test analytes were volatile fragrance compounds, included in a list of 24 chemicals classified as suspected allergens according to Directive 2003/15/CE. The considered compounds were detected at 195 nm and p-anisaldehyde was chosen as internal standard. The background electrolyte consisted of a standard microemulsion made of 90.95% 10mM borax buffer, pH 9.2, 1.05% n-heptane, 8.00% SDS/n-butanol in 1:2 ratio, to which 40 mM methyl-?-cyclodextrin was added. Temperature and voltage were set at 20 °C and 25 kV, respectively. These experimental conditions allowed separation of the compounds to be obtained in about 20 min. The method was applied to real samples made up of rinse-off scented products. The results obtained using the standard microemulsion as pseudostationary phase showed its high resolution power, capable of effectively separating a complex mixture of analytes. Microemulsion electrokinetic chromatography was confirmed to have a great potential for different analytical challenges, holding up the possibility of using this technique as a good and complementary alternative to HPLC methods for routine analysis. PMID:21035646

  3. Polymer/clay/wood nanocomposites: The effect of incorporation of nanoclay into the wood/polymer composites

    NASA Astrophysics Data System (ADS)

    Hetzer, Max E.

    Thermoplastic composites play an important role in our society. The uses of these composites range from cookware to components for the space shuttle. In recent years, researchers at Toyota developed numerous methods of preparation for composites made from olefins and inorganic fillers such as clay and calcium carbonate. Wood fibers have been used as reinforcing filler in polymer matrices for the past several decades. The advantages of using wood fibers as reinforcing fillers are: the low cost of the fibers (or flour), low density, and resistance to breakage. The disadvantage of using wood as a filler is the thermal instability of wood above 200 °C. The majority of thermoplastics exhibit melting points between 160 and 220 °C, which is in the range of thermal decomposition of wood. Nanoclay was first successfully used as a filler in polyolefin materials by the Toyota research team in early 90s. It was found that the addition of a small amount (< 5 wt.%) of nanoclay increased the mechanical properties of a Nylon-6 matrix dramatically. Since Nylon-6 is a hydrophilic material no compatibilizer was necessary to exfoliate the nanoclay. The use of compatibilizers such as maleic modified polyethylenes (MAPEs) is necessary upon addition of nanoclay to a hydrophobic polyolefin systems such polyethylene (PE) or polypropylene (PP). Few researchers have attempted to reinforce the polymer matrix via the use of the nanoclay for use as a matrix in wood/polymer composites. High molecular weight and low molecular weight MAPEs have been used to enhance the bonding between the nanoclay and the polymer matrix as well as between the wood flour and the polymer matrix. The effects of combinations of the high and low molecular weight MAPEs on the mechanical and thermal properties of polymer/clay nanocomposites (PCNs) and of wood/polymer/clay composites (WPCs) were investigated. The effects of adding nanoclay to wood/polymer systems on the mechanical and thermal properties of the composites were also investigated. A model based on the Halpin-Tsai model was developed that predicts the (Young's) modulus-temperature relationship of the composites based on discontinuous fillers. It was found that the molecular weight of the compatibilizer significantly affects the exfoliation/dispersion of the nanoclay within the polymer matrix. A compatibilizer containing a high Mw fraction based on high density polyethylene (HDPE) and a low Mw fraction based on linear low density polyethylene (LLDPE) was found to be the most effective at enhancing the thermal and mechanical properties of PCNs and WPCs. A compatibilizer containing greater than 60 wt.% high Mw fraction resulted in a 30% increase of the modulus and a 15°C increase of the heat deflection temperature (HDT). The addition of the nanoclay had a detrimental effect on the moduli of PCNs and WPCs when a low Mw compatibilizer based on LLDPE was used. The moduli of these composites increased with increasing high Mw content of the compatibilizer and increasing nanoclay content. The addition of the nanoclay to wood/polymer composites resulted in an increased modulus of elasticity and HDT of these composites. The developed model quantitatively predicts the modulus-temperature relationship of the fiber containing composites. It was found that the modulus of the composites varies linearly with temperature and was highly dependent on the exfoliation of the nanoclay within the polymer matrix.

  4. Dynamics of a New Strain of the H1N1 Influenza A Virus Incorporating the Effects of Repetitive Contacts

    PubMed Central

    Pongsumpun, Puntani; Tang, I-Ming

    2014-01-01

    The respiratory disease caused by the Influenza A Virus is occurring worldwide. The transmission for new strain of the H1N1 Influenza A virus is studied by formulating a SEIQR (susceptible, exposed, infected, quarantine, and recovered) model to describe its spread. In the present model, we have assumed that a fraction of the infected population will die from the disease. This changes the mathematical equations governing the transmission. The effect of repetitive contact is also included in the model. Analysis of the model by using standard dynamical modeling method is given. Conditions for the stability of equilibrium state are given. Numerical solutions are presented for different values of parameters. It is found that increasing the amount of repetitive contacts leads to a decrease in the peak numbers of exposed and infectious humans. A stability analysis shows that the solutions are robust. PMID:24744816

  5. Effect of incorporation of silane in the bonding agent on the repair potential of machinable esthetic blocks

    PubMed Central

    Zaghloul, Hanaa; Elkassas, Dina Wafik; Haridy, Mohamed Fouad

    2014-01-01

    Objective: To investigate the repair potential of CAD/CAM (computer-aided design/computer-aided manufacturing) ceramic and composite blocks using a silane-containing bonding agent with different repair protocols. Materials and Methods: Twenty-four discs were constructed from CAD/CAM ceramic and composite blocks. The discs were divided into six groups according to surface pre-treatment employed; GI: Diamond stone roughening (SR), GII: SR+ silanization (SR+S), GIII: Hydrofluoric acid etching (HF), GIV: HF+ silanization (HF+S), GV: Silica coating (SC), GVI: SC+ silanization (SC+S). Silane-containing bonding agent (Single Bond Universal adhesive, 3M ESPE) was applied to the pre-treated discs. Prior to light curing, irises were cut from tygon tubes (internal diameter = 0.8 mm and height = 0.5 mm) and mounted on each treated surface. Nanofilled resin composite (Filtek Z350XT, 3M ESPE) was packed into the cylinder lumen and light-cured (n = 10). The specimens were subjected to microshear bond strength testing (?-SBS) using universal testing machine. Failure modes of the fractured specimens were analyzed using field emission scanning electron microscope (FESEM). Eight representative discs were prepared to analyze the effect of surface treatments on surface topography using FESEM. ?-SBS results were analyzed using ANOVA and Tukeys post-hoc test. Results: Three-way ANOVA results showed that the materials, surface pre-treatment protocols, and silanization step had a statistically significant effect on the mean ?-SBS values at P ? 0.001. For ceramic discs, the groups were ranked; GIV (24.45 ± 7.35)> GVI ((20.18 ± 2.84)> GV (7.14 ± 14)= GII (6.72 ± 1.91)=GI (6.34 ± 2.21)=GIII (5.72 ± 2.18). For composite discs, groups were ranked; GI (24.98 ± 7.69)=GVI (24.84 ± 7.00) >GII (15.85 ± 5.29) =GV (14.65 ± 4.5)= GIV (14.24 ± 2.95)? GIII ((9.37 ± 2.78). Conclusion: The additional silanization step cannot be omitted if the repair protocol comprises of either hydrofluoric acid etching or silica coating for both CAD/CAM esthetic restorative materials. However, this step can be suppressed by using silane-containing adhesive with diamond stone roughened repair protocol. PMID:24966745

  6. Effect of photoperiod on the rate of 3H-thymidine incorporation of epididymal principal cells in adult Syrian hamsters

    SciTech Connect

    Johnson, L.; Bartke, A. (Texas A M University, College Station (USA))

    1991-04-01

    Photoperiod-induced cycles of gonadal regression and recrudescence in the Syrian hamster were used to determine if epididymal growth in adults involves mitotic activity of principal cells. In Experiment 1, the following groups of adult hamsters were examined: induced recrudescing (5L:19D (5 hr light and 19 hr dark) for 13 wk followed by 14L:10D for at least 3 wk), spontaneous recrudescing (5L:19D for 25 wk), and active gonadal state (14:10D). In Experiment 2, adult hamsters were divided into the following groups: induced recrudescing, active, and regressed (5L:19D for 16 wk). Hamsters received subcutaneous injections of 0.5 microCi 3H-thymidine/g body weight three times/wk for 3 wk. The epididymis was fixed in a glutaraldehyde followed by osmium, embedded in Epon 812, and sectioned at 1 micron. Slides were dipped in Kodak NTB-3 emulsion, exposed for 2 or 3 months, developed, and evaluated for isotopic labeling of principal and basal cell nuclei by scoring 500 to 1,000 nuclei. In Experiment 1, the percentages of labeled principal cell nuclei for the induced recrudescing, spontaneous recrudescing, and active groups were 26 {plus minus} 2%, 23 {plus minus} 5%, and 9 {plus minus} 1%, respectively. Considering the intermittent availability of 3H-thymidine during 21 days, this represents daily recruitment of 6.3%, 5.6%, and 2.2%, respectively. In Experiment 2, the percentages of labeled principal cell nuclei for induced recrudescing, active, and regressed groups were 12 {plus minus} 4%, 3 {plus minus} 1%, and 4 {plus minus} 1%, respectively. There was no effect of photoperiod on labeling pattern of basal cells (1.5 {plus minus} 0.6%, 1.2 {plus minus} 0.1%, 0.4 {plus minus} 0.1% for the three photoperiod groups, respectively).

  7. Analysis of the photodynamic therapy effects by using chloroaluminum phthalocyanine incorporated into liposomes and fractionation energy in colon tumors of rats

    NASA Astrophysics Data System (ADS)

    Duarte, Janaina; Hage, Raduan; Tedesco, Antonio C.; Pazos, Marcelo; Martin, Airton A.; Plapler, Helio

    2006-02-01

    Photodynamic therapy (PDT) has been widely studied in the last decades and it is becoming a promising tool in the treatment of tumors of many kinds. PDT is based on photoactivation of a sensitized drug that is restrained in the tumor cells, producing highly reactive species that can destroy tumoral cells with minimum collateral effect. This study aimed to evaluate the effect of the PDT in induced neoplasias of the colon by 1,2-dimetilhidrazine in rats, using as photosensitizing drug the chloroaluminum phthalocyanine incorporated to the liposomes and to compare the methods of irradiation using continuous or fractionated energy in PDT. Ten Wistar rats were distributed randomly in 3 groups (G1, G2 and C), anaesthetized and submitted to PDT with of fractionated (G1) or continuum (G2) irradiation energy using as a source of excitement an InGaAl laser. After 3 hours of the laser irradiation, 2 animals of the G1 group, 2 animals of the G2 group and 1 animal of C group were sacrificed and samples of tumoral tissue were collected for histological analysis; the same procedure was carried through 24 hours after irradiation. There were no significant differences between the extensions of the induced areas of necrosis for PDT in the groups under fractionated or continuous irradiation for the parameters used in this study. New studies must be carried through, using different parameters and intervals of laser irradiation, aiming to maximize the effect of the PDT for the treatment of colon tumors.

  8. Kinetic Effects on B/Ca in Synthetic Calcite: Implications for B(OH)4- and B(OH)3 Incorporation.

    NASA Astrophysics Data System (ADS)

    Uchikawa, J.; Penman, D. E.; Zachos, J. C.; Zeebe, R. E.

    2014-12-01

    In this experimental study, we investigated the influence of solution chemistry on the boron abundance in synthetic calcite using a pH-stat system. We systematically varied solution pH as well as the concentration of total dissolved boron (BT), inorganic carbon (DIC) and calcium ion. We found robust positive correlations between boron abundance in calcite (measured as the boron to calcium ratio, B/Ca) and solution pH, [BT], [DIC] as well as [Ca2+], when a given parameter was solely manipulated while keeping the others constant. Except for [BT], raising these parameters also caused simultaneous increase in calcite saturation and precipitation rate. We found that much of the B/Ca variability as a results of the chemical manipulations tested here can be essentially explained by just precipitation rate and the [BT]/[DIC] ratio in the solution, which was particularly the case for relatively rapidly precipitated calcite samples. On the contrary, for relatively slowly precipitated samples, the [B(OH)4-]/[DIC] and [BT]/[DIC] ratios are equally effective in explaining the B/Ca variability (along with precipitation rate). This observation suggests the possibility of a hitherto unrecognized and apparently kinetically-controlled mechanism that promotes B(OH)3 incorporation for rapidly forming calcite. In recent years both the abundance and isotopic composition of boron in marine biogenic CaCO3 (B/Ca and ?11B, respectively) has been increasingly utilized to constrain past ocean carbonate chemistry. But these boron-based proxies crucially rely on the first order assumption that B(OH)4- is predominantly incorporated. Thus, the possibility of kinetically-controlled B(OH)3 incorporation presented here raises a concern for the reliability of the B/Ca and ?11B proxy. If it is similarly applicable to foraminifers, shell B/Ca and ?11B may be prone to significant uncertainties due to long-term changes in seawater chemistry. Our results further suggest that future calibrations of these proxies clearly need to take calcification rates into consideration.

  9. The Effect of the Progression of Vitamin A Deficiency on Glucose, Galactose and Mannose Incorporation into Sugar Phosphates and Sugar Nucleotides in Hamster

    Microsoft Academic Search

    Liver SHARADA SHANKAR; LUIGI M. DE LUCA

    The incorporation of (2-3H)mannose into dolichyl phosphate mannose and glycoproteins is markedly reduced in livers of vitamin A-deficient ham sters. To determine whether vitamin A deficiency se lectively alters the level of mannose incorporation into sugar phosphates and sugar nucleotides, we studied the in vivo incorporation of (2-3H)mannose, (5-3H)glu- cose, and (4,5-3H)galactose into sugar phosphates and sugar nucleotides. Male hamsters

  10. Optimal power flow incorporating voltage collapse constraints

    Microsoft Academic Search

    William Rosehart; C. Canizares; Victor Quintana

    1999-01-01

    The paper presents applications of optimization techniques to voltage collapse studies. First a “maximum distance to voltage collapse” algorithm that incorporates constraints on the current operating conditions is presented. Second, an optimal power flow formulation that incorporates voltage-stability criteria is proposed. The algorithms are tested on a 30-bus system using a standard power flow model, where the effect of limits

  11. Pilot-scale ex situ electrokinetic restoration of saline greenhouse soil

    Microsoft Academic Search

    Do-Hyung Kim; Jung-Min Cho; Kitae Baek

    Purpose  This study was conducted to investigate the feasibility of using an ex situ electrokinetic system for the restoration of saline\\u000a greenhouse soil.\\u000a \\u000a \\u000a \\u000a \\u000a Materials and methods  An experiment was conducted in a pilot-scale reactor (1?×?1?×?0.25 m) during 14 days.\\u000a \\u000a \\u000a \\u000a Results and discussion  Chloride accumulated in the top layer through pore-water evaporation. There was no removal of the nitrate in the top layer\\u000a because of the

  12. Electrokinetic Assembly of One-Dimensional Nanoparticle Chains with Cucurbit[7]uril Controlled Subnanometer Junctions

    PubMed Central

    2013-01-01

    One-dimensional (1D) nanoparticle chains with defined nanojunctions are of strong interest due to their plasmonic and electronic properties. A strategy is presented for the assembly of 1D gold-nanoparticle chains with fixed and rigid cucurbit[n]uril-nanojunctions of 9 Å. The process is electrokinetically accomplished using a nanoporous polycarbonate membrane and controlled by the applied voltage, the nanoparticle/CB[n] concentration ratio, time and temperature. The spatial structure and time-resolved analysis of chain plasmonics confirm a growth mechanism at the membrane nanopores. PMID:24180422

  13. Separation of carbamazepine and five metabolites, and analysis in human plasma by micellar electrokinetic capillary chromatography

    Microsoft Academic Search

    Maria Augusta Raggi; Vincenzo Pucci; Alessandra Maurizio; Jan Muzikar; Ernst Kenndler

    2002-01-01

    A rapid and feasible method was developed for the analysis of carbamazepine and its five metabolites (10,11-dihydro-10,11-epoxycarbamazepine, 10,11-dihydro-10,11-dihydroxycarbamazepine, 10,11-dihydro-10-hydroxycarbamazepine, 2-hydroxycarbamazepine and 3-hydroxycarbamazepine) in human plasma. Separation of the analytes is based on micellar electrokinetic chromatography, in untreated fused-silica capillary (48.5\\/40.0 cm length, 50 ?m I.D.) with phosphate buffer (30 mM, pH 8.00) as background electrolyte, containing 50 mM sodium dodecylsulfate,

  14. Studies on the incorporation of velvet bean (Mucuna pruriens var. utilis) as an alternative protein source in poultry feed and its effect on growth performance of broiler chickens.

    PubMed

    Vadivel, Vellingiri; Pugalenthi, Muthiah

    2010-10-01

    The effect of replacement of soybean meal by the velvet bean meal as an alternative protein ingredient on the growth performance of broiler chickens was investigated. The raw seeds of velvet bean [Mucuna pruriens (L.) DC. var. utilis (Wall. ex Wight) Baker ex Burck], an under-utilized food legume collected from South India, was found to contain appreciable levels of crude protein (273.2 g/kg DM), lipid (60.61 g/kg DM), neutral detergent fiber (84.3 g/kg DM), and ash content (56.04 g/kg DM). Soaking in 0.2% sodium bicarbonate solution + autoclaving treatment caused a substantial reduction on the levels of various antinutritional compounds such as tannins (84%), L: -Dopa (79%), phytic acid (87%), raffinose (93%), stachyose (83%), verbascose (73%), haemagglutinating activity (84%), trypsin inhibitor activity (77%), and alpha-amylase inhibitor activity (78%) without affecting the nutritional quality of velvet bean seeds. The processed velvet bean meal was incorporated as an alternative protein source by replacing soybean meal protein at 0, 20%, 40%, 60%, 80%, and 100% levels in the broiler diets. Replacement of soybean meal protein up to 40% level, which corresponds to the inclusion of velvet bean meal up to 15.7% and 11% in the starter and finisher phase poultry feeds, respectively, exhibited better growth performance of broiler birds without any adverse effects. PMID:20509048

  15. Flexible Workflow Incorporated with RBAC

    Microsoft Academic Search

    Yuqing Sun; Xiangxu Meng; Shijun Liu; Peng Pan

    2005-01-01

    \\u000a In this paper, we propose a new model to incorporate RBAC into a flexible workflow system. Without compromising the flexibility\\u000a of workflow, this model can effectively enhance the security control of the user access to the workflow system. Specifically,\\u000a it provides the corresponding mechanism to maintain the constraint consistency in dynamic management of workflow. We present\\u000a the basic design and

  16. Incorporation of high levels of extruded lupin in diets for rainbow trout ( Oncorhynchus mykiss): nutritional value and effect on thyroid status

    Microsoft Academic Search

    Christine Burel; Thierry Boujard; Geneviève Corraze; Sadasivam J Kaushik; Gilles Boeuf; Koen A Mol; Serge Van Der Geyten; Eduard R Kühn

    1998-01-01

    Three experiments and a digestibility trial were conducted in order to assess the incorporation of extruded lupin (Lupinus albus) in diets for juvenile rainbow trout. Digestibility of protein and phosphorus were higher in lupin than in fish meal, but digestibility of dry matter and energy were lower. The first trial was designed to determine the maximum level of incorporation of

  17. Bacterial Surface Appendages Strongly Impact Nanomechanical and Electrokinetic Properties of Escherichia coli Cells Subjected to Osmotic Stress

    Microsoft Academic Search

    Grégory Francius; Pavel Polyakov; Jenny Merlin; Yumiko Abe; Jean-Marc Ghigo; Christophe Merlin; Christophe Beloin; Jérôme F. L. Duval; Igor Sokolov

    2011-01-01

    The physicochemical properties and dynamics of bacterial envelope, play a major role in bacterial activity. In this study, the morphological, nanomechanical and electrohydrodynamic properties of Escherichia coli K-12 mutant cells were thoroughly investigated as a function of bulk medium ionic strength using atomic force microscopy (AFM) and electrokinetics (electrophoresis). Bacteria were differing according to genetic alterations controlling the production of

  18. Microemulsion electrokinetic chromatography of drugs varying in charge and hydrophobicity Part II: Strategies for optimization of separation

    Microsoft Academic Search

    Valérie Harang; Sven P. Jacobsson; Douglas Westerlund

    2004-01-01

    The separation of anionic, cationic, and neutral drugs in microemulsion electrokinetic chromatography (MEEKC) was studied. The concentration of sodium dodecyl sulfate (SDS; surfactant) and 2-propanol (organic solvent) was varied in a three-level full factorial design. 29 different model substances were chosen with different hydropho- bicities and charges (neutral, positive, and negative). The models were calculated by means of multiple linear

  19. Electrokinetic probes for single-step screening of polyol stereoisomers: the virtues of ternary boronate ester complex formation.

    PubMed

    Kaiser, Claire; Segui-Lines, Giselle; D'Amaral, Jason C; Ptolemy, Adam S; Britz-McKibbin, Philip

    2008-01-21

    Electrokinetic probes based on the differential migration of ternary boronate ester complexes permit the selective analysis of micromolar levels of UV-transparent polyol stereoisomers in urine samples via dynamic complexation-capillary electrophoresis that is applicable to single-step screening of in-born errors of sugar metabolism, such as galactosemia. PMID:18399200

  20. The determination of glucoraphanin in broccoli seeds and florets by solid phase extraction and micellar electrokinetic capillary chromatography

    Microsoft Academic Search

    V. Craige Trenerry; Domenico Caridi; Aaron Elkins; Osaana Donkor; Rod Jones

    2006-01-01

    A robust method for the determination of glucoraphanin in broccoli (brassica oleracea ssp. italica ‘Marathon’) seeds and florets has been developed using solid phase extraction (SPE) and micellar electrokinetic capillary chromatography (MECC) as the determinative step. Glucosinolates were extracted from the broccoli seeds and florets with hot water. Unwanted impurities were removed by passing the extracts through C18 and protonated

  1. Theory of ac electrokinetic behavior of spheroidal cell suspensions with an intrinsic dispersion Lei Gao,1,2

    E-print Network

    Huang, Ji-Ping

    shape, the dispersion strength, and the intrinsic frequency on the dielectric dispersion, DEP, and ER dielectric dispersion. Actually, such an intrinsic dielectric dispersion often occurs due to the surfaceTheory of ac electrokinetic behavior of spheroidal cell suspensions with an intrinsic dispersion

  2. Removal of contaminants from fine-grained soils using electrokinetic flushing. Semiannual report, July 1 through December 31, 1992

    Microsoft Academic Search

    B. E. Reed; M. T. Berg

    1993-01-01

    This report details the status of work conducted on the use of electrokinetics (EK) to remediate a fine grained soil contaminated with lead. The experimental work entails soil collection and characterization, soil adsorption and desorption of lead, and experimental setup construction and testing. Test soil was collected from Northern Erie County, New York and underwent standard preparation and physical\\/chemical characterization.

  3. Nepal CRS project incorporates.

    PubMed

    1983-01-01

    The Nepal Contraceptive Retail Sales (CRS) Project, 5 years after lauching product sales in June 1978, incorporated as a private, nonprofit company under Nepalese management. The transition was finalized in August 1983. The Company will work through a cooperative agreement with USAID/Kathmandu to complement the national family planning goals as the program continues to provide comtraceptives through retail channels at subsidized prices. Company objectives include: increase contraceptive sales by at least 15% per year; make CRS cost effective and move towards self sufficiency; and explore the possibility of marketing noncontraceptive health products to improve primary health care. After only5 years the program can point to some impressive successes. The number of retial shops selling family planning products increased from 100 in 1978 to over 8000, extending CRS product availability to 66 of the country's 75 districts. Retail sales have climbed dramatically in the 5-year period, from Rs 46,817 in 1978 to Rs 271,039 in 1982. Sales in terms of couple year protection CYP) have grown to 24,451 CYP(1982), a 36% increase over 1980 CYP. Since the beginning of the CRS marketing program, total distribution of contraceptives--through both CRS and the Family Planning Maternal and Child Haelth (FP/MCH) Project--has been increasing. While the FP/MCH program remains the largest distributor,contribution of CRS Products is increasing, indicating that CRS is creating new product acceptors. CRS market share in 1982 was 43% for condoms and 16% for oral contraceptives (OCs). CRS markets 5 products which are subsidized in order to be affordable to consumers as well as attractive to sellers. The initial products launched in June 1978 were Gulaf standard dose OCs and Dhaal lubricated colored condoms. A less expensive lubricates, plain Suki-Dhaal condom was introduced in June 1980 in an attempt to reach poorer rural populations, but rural distribution costs are excessive and Suki-Dhaal sales have never been high. In 1982 2 additional products were introduced--Nilocan (Norminest) low does OCs and Kamal Neo Sampoon foaming tablets. The CRS program recruited and trained its own sales representatives who work shop to shop, promoting products and educating retailers and consumers. An important part of the communication starategy includes consumer and retailer education. Advertising messages were developed to increase brand awareness, create demand, educate consumers about side effects of OCs, and to identify contraceptives as a means of adequately space children. PMID:12312964

  4. Integrated electrokinetic sample fractionation and solid-phase extraction in microfluidic devices.

    PubMed

    Wang, Zhen; Jemere, Abebaw B; Harrison, D Jed

    2012-11-01

    A microfluidic device that performs "in space" sample fractionation, collection, and preconcentration for proteomics is described. Effluents from a 2.75 mm long fractionation channel, focused via sheath flow, were sequentially delivered into an array of 36-collection channels containing monolithic polymer beds for SPE. Optimum conditions for the device design, and simultaneous photolytic fabrication of 36 monolithic columns in the 36 channels, as well as for their proper performance in electrokinetic sample fractionation and collection are described. A hydrophobic butyl methacrylate-based monolithic porous polymer was copolymerized with an ionizable monomer, acryloamido-methyl-propane sulfonate, to form a polymer monolith for SPE that also sustains cathodic electroosmotic flow. The SPE bed was made deep enough to greatly reduce the linear flow rate within the bed, in order to compensate for the lower electroosmotic mobility of the cationically charged SPE bed relative to the glass walled device. Under these conditions, electrokinetic fractionation of a protein sample resulted in tightly focused sample zones delivered into each of the 36-channel polymer beds with no observed crosscontamination. Monolithic columns showed reproducible performance with preconcentration factor of 30 for 2 min loading time. The ability to fractionate, collect, and preconcentrate samples on a microfluidic platform will be especially useful for automated or continuous operation of these devices in proteomics research. PMID:22949294

  5. Laboratory pre-assays for soil remediation by electro synthesis of oxidants and their electrokinetic distribution.

    PubMed

    Mikkola, Heidi; Schmale, Julia Y; Wesner, Wolfgang; Petkovska, Slagjana

    2008-07-01

    The feasibility of an innovative electrokinetic soil remediation technique for an in situ application against fuel-contaminated soil has been studied in this work. This technique combines the anodic production of oxidizing agents on boron-doped diamond (BDD) electrode surfaces with their electrokinetic distribution in soil. In this study, the production of oxidizing agents, i.e., hydroxyl radicals (OH degrees ) and peroxodisulfate (S(2)O(8)(2 -)), from a 0.85 M sodium sulfate electrolyte with mechanically implanted BDD anodes at room temperature has been investigated. It was found that about 12 mmol/L of oxidants could be produced after 10 Ah/L with a current density of 200 mA/cm(2). For investigating the transport velocity of peroxodisulfate in soil a vertical column system has been created. Experimental results show linear velocity behaviour for the oxidants' migration in 100% sand soil reaching up to 2 cm/h at an electrical gradient of 4 V/cm. As for different soil textures which have been tested, the assays stated that the highest velocity can be achieved in a 100% silt soil with 3.3 cm/h. PMID:18569302

  6. Pore-scale dispersion in electrokinetic flow through a random sphere packing.

    PubMed

    Hlushkou, Dzmitry; Khirevich, Siarhei; Apanasovich, Vladimir; Seidel-Morgenstern, Andreas; Tallarek, Ulrich

    2007-01-01

    The three-dimensional velocity field and corresponding hydrodynamic dispersion in electrokinetic flow through a random bulk packing of impermeable, nonconducting spheres are studied by quantitative numerical analysis. First, a fixed bed with interparticle porosity of 0.38 is generated using a parallel collective-rearrangement algorithm. Then, the interparticle velocity field is calculated using the lattice-Boltzmann (LB) method, and a random-walk particle-tracking method is finally employed to model advection-diffusion of an inert tracer in the LB velocity field. We demonstrate that the pore-scale velocity profile for electroosmotic flow (EOF) is nonuniform even under most ideal conditions, including a negligible thickness of the electrical double layer compared to the mean pore size, a uniform distribution of the electrokinetic potential at the solid-liquid interface, and the absence of applied pressure gradients. This EOF dynamics is caused by a nonuniform distribution of the local electrical field strength in the sphere packing and engenders significant hydrodynamic dispersion compared to pluglike EOF through a single straight channel. Both transient and asymptotic dispersion behaviors are analyzed for EOF in the context of packing microstructure and are compared to pressure-driven flow in dependence of the average velocity through the bed. A better hydrodynamic performance of EOF originates in a still much smaller amplitude of velocity fluctuations on a mesoscopic scale (covering several particle diameters), as well as on the microscopic scale of an individual pore. PMID:17194128

  7. Selecting enhancing solutions for electrokinetic remediation of dredged sediments polluted with fuel.

    PubMed

    Rozas, F; Castellote, M

    2015-03-15

    In this paper a procedure for selecting the enhancing solutions in electrokinetic remediation experiments is proposed. For this purpose, dredged marine sediment was contaminated with fuel, and a total of 22 different experimental conditions were tested, analysing the influence of different enhancing solutions by using three commercial non-ionic surfactants, one bio-surfactant, one chelating agent, and one weak acid. Characterisation, microelectrophoretic and electrokinetic remediation trials were carried out. The results are explained on the basis of the interactions between the fuel, the enhancing electrolytes and the matrix. For one specific system, the electrophoretic zeta potential, (?), of the contaminated matrix in the solution was found to be related to the electroosmotic averaged ? in the experiment and not to the efficiency in the extraction. This later was correlated to a parameter accounting for both contributions, the contaminant and the enhancing solution, calculated on the basis of differences in the electrophoretic ? in different conditions which has allowed to propose a methodology for selection of enhancing solutions. PMID:25559497

  8. Effect of ultraviolet radiation exposure on room-temperature hydrogen sensitivity of nanocrystalline doped tin oxide sensor incorporated into microelectromechanical systems device

    SciTech Connect

    Shukla, Satyajit; Agrawal, Rajnikant; Cho, Hyoung J.; Seal, Sudipta; Ludwig, Lawrence; Parish, Clyde [Advanced Materials Processing and Analysis Center (AMPAC) and Mechanical Materials Aerospace Engineering (MMAE) Department, Engineering 381, University of Central Florida, 4000 Central Florida Boulevard, Orlando, Florida 32816 (United States); National Aeronautics and Space Administration (NASA), John F. Kennedy Space Center, Kennedy Space Center (KSC), Florida 32899 (United States)

    2005-03-01

    The effect of ultraviolet (UV) radiation exposure on the room-temperature hydrogen (H{sub 2}) sensitivity of nanocrystalline indium oxide (In{sub 2}O{sub 3})-doped tin oxide (SnO{sub 2}) thin-film gas sensor is investigated in this article. The present sensor is incorporated into microelectromechanical systems device using sol-gel dip-coating technique. The present sensor exhibits a very high sensitivity, as high as 65 000-110 000, at room temperature, for 900 ppm of H{sub 2} under the dynamic test condition without UV exposure. The H{sub 2} sensitivity is, however, observed to reduce to 200 under UV radiation, which is contrary to the literature data, where an enhanced room-temperature gas sensitivity has been reported under UV radiation. The observed phenomenon is attributed to the reduced surface coverage by the chemisorbed oxygen ions under UV radiation, which is in consonance with the prediction of the constitutive equation, proposed recently by the authors, for the gas sensitivity of nanocrystalline semiconductor oxide thin-film sensors.

  9. [A specific effect of blue light on the incorporation of photosynthetically assimilated (14)C into the protein of fern sporelings [dryopteris filix-mas (L.) Schott

    PubMed

    Payer, H D; Mohr, H

    1969-09-01

    Morphogenesis and metabolism of the early gametophytes (=sporelings) of the common male fern are controlled by light. The "normal" two-dimensional development of the gametophytes takes place only in white or blue light; in red light alone, on the other hand, the sporelings remain filamentous even under conditions of equal photosynthetic rate.The problem has been whether blue light exerts its morphogenic influence through differential gene activation. In other words: does blue light mediate the synthesis of "morphogenic enzymes" which are required for "normal" morphogenesis. In an earlier paper (DRUMM and MOHR, 1967) we have shown that blue light increases the rate of RNA synthesis within an hour whereas the first indication of a morphogenic change due to blue light is only discernible about 3 hours after the onset of blue light (Figs. 1,2). Furthermore we have shown (MOHR, 1965) that Actinomycin D specifically inhibits the blue light mediated morphogenic alterations, and BERGFELD (1967) has shown that blue light will rapidly lead to changes in nuclei and nucleoli in the fern sporelings. In the present paper it has been shown that blue light does increase the rate of protein synthesis about an hour after the transfer of the sporelings from the red into the blue light of equal quantum flux density (350 pE·cm(-2)·s(-1)).The rate of protein synthesis was measured in shortterm experiments (40min) using (14)CO2. The photosynthetic rate was the same in red and blue; it was not influenced by the transfer(Fig. 3). Likewise the rate of (14)C incorporation into the pool of free amino acids was not significantly different in red and blue light (Fig.4). On the other hand, the rate of incorporation of (14)C into the protein increased rapidly after the transfer of the sporelings from the red into the blue light (Fig. 5). The same phenomenon (no influence of blue light on the specific activity of the free amino acid; a strong promotive influence on the specific activity of the protein-bound amino acid) was observed in the case of alanine which was investigated in detail (Figs. 6, 7). Since the increase of the protein content of the sporelings is not significant during the first six hours after transfer to blue light (Fig. 8) the protein induced by blue light and directly related to morphogenesis can only be a very small fraction of the total protein of the sporeling.The data strongly support the hypothesis (OHLENROTH and MOHR, 1964), that the morphogenic effect of blue light on the fern sporelings is due to the induction of "morphogenic enzymes" by blue light. PMID:24515827

  10. Bearings Incorporating Deadband Rollers

    NASA Technical Reports Server (NTRS)

    Gualtieri, Guy V.

    1996-01-01

    Bearings in high-pressure turbopump redesigned to incorporate rollers allowing limited axial motion within small deadband. Does not permit radial deadband motion. Axial deadband motion used for rotor-thrust-balance control. Design eliminates some nonlinearities in dynamics of pump rotor and assists in suppressing vibrations at harmonics of frequency of rotation.

  11. Antimicrobial assays of natural extracts and their inhibitory effect against Listeria innocua and fish spoilage bacteria, after incorporation into biopolymer edible films.

    PubMed

    Iturriaga, L; Olabarrieta, I; de Marañón, I Martínez

    2012-08-01

    The antimicrobial activity of twelve natural extracts was tested against two fish spoilage bacteria (Pseudomonas fluorescens and Aeromonas hydrophila/caviae) and Listeria innocua, in order to assess their potential utilization in the preservation and safety of minimally processed fish products. After a screening of the active extracts by agar diffusion and vapour diffusion methods, oregano and thyme essential oils and citrus extract were selected. The minimum inhibitory concentration (MIC) of the selected extracts was determined by disc diffusion method against target bacteria and at two temperatures: bacteria's optimal growth temperature (30 °C or 37 °C) and refrigeration temperature (4 °C). Due to its better solubility, lack of odour and greater inhibitory effect obtained against L. innocua at refrigerated temperature, citrus extract was selected and incorporated at 1% (v/v) into different biopolymer film forming solutions (gelatin, methyl cellulose and their blend 50:50 w/w). The antimicrobial activity of the developed films was then evaluated, just after preparation of the films and after one month of storage at 43±3% relative humidity and 24±3 °C. Regardless of the biopolymer matrix, all the developed films showed antimicrobial activity against the target bacteria. The most sensitive bacterium towards active films was L. innocua while P. fluorescens appeared as the most resistant one, in accordance with the previously performed antimicrobial tests for pure extracts. The differences in activity of the films between the tested two temperatures were not significant except for L. innocua, for which three times higher inhibition diameters were observed at refrigerated temperature. The inhibitory effectiveness of the films against the tested strains was maintained regardless of the biopolymer matrix for at least one month. Therefore, these edible films show potential for their future use in fresh fish fillets preservation. PMID:22824340

  12. Electrokinetic and acoustic manipulations of colloidal and biological particles 

    E-print Network

    Park, Seungkyung

    2009-05-15

    Recent advances in microfluidic technologies have enabled integration of the functional units for biological and chemical analysis onto miniaturized chips, called Labon- a-Chip (LOC). However, the effective manipulation and control of colloidal...

  13. Effect of polyunsaturated fatty acids and phospholipids on ( sup 3 H)-vitamin E incorporation into pulmonary artery endothelial cell membranes

    SciTech Connect

    Sekharam, K.M.; Patel, J.M.; Block, E.R. (Univ. of Florida College of Medicine, Gainesville (USA))

    1990-12-01

    Vitamin E, a dietary antioxidant, is presumed to be incorporated into the lipid bilayer of biological membranes to an extent proportional to the amount of polyunsaturated fatty acids or phospholipids in the membrane. In the present study we evaluated the distribution of incorporated polyunsaturated fatty acids (PUFA) and phosphatidylethanolamine (PE) in various membranes of pulmonary artery endothelial cells. We also studied whether incorporation of PUFA or PE is responsible for increased incorporation of (3H)-vitamin E into the membranes of these cells. Following a 24-hr incubation with linoleic acid (18:2), 18:2 was increased by 6.9-, 9.2-, and 13.2-fold in plasma, mitochondrial, and microsomal membranes, respectively. Incorporation of 18:2 caused significant increases in the unsaturation indexes of mitochondrial and microsomal polyunsaturated fatty acyl chains (P less than .01 versus control in both membranes). Incubation with arachidonic acid (20:4) for 24 hr resulted in 1.5-, 2.3-, and 2.4-fold increases in 20:4 in plasma, mitochondrial, and microsomal membranes, respectively. The unsaturation indexes of polyunsaturated fatty acyl chains of mitochondrial and microsomal membranes also increased (P less than .01 versus control in both membranes). Although incubations with 18:2 or 20:4 resulted in several-fold increases in membrane 18:2 or 20:4 fatty acids, incorporation of (3H)-vitamin E into these membranes was similar to that in controls. Following a 24-hr incubation with PE, membrane PE content was significantly increased, and (3H)-vitamin E incorporation was also increased to a comparable degree, i.e., plasma membrane greater than mitochondria greater than microsomes. Endogenous vitamin E content of the cells was not altered because of increased incorporation of PE and (3H)-vitamin E.

  14. Determination of the chiral and achiral related substances of methotrexate by cyclodextrin-modified micellar electrokinetic chromatography.

    PubMed

    Gotti, Roberto; El-Hady, Deia Abd; Andrisano, Vincenza; Bertucci, Carlo; El-Maali, Nagwa Abo; Cavrini, Vanni

    2004-08-01

    A cyclodextrin-modified micellar electrokinetic chromatographic (CD-MEKC) method for the determination of the most important potential impurities of methotrexate (MTX): 2,4-diamino-6-(hydroxymethyl)pteridine, aminopterine hydrate, 4-[N-(2-amino-4-hydroxy-6-pteridinylmethyl)-N-methylamino] benzoic acid, 4-[N-(2,4-diamino-6-pteridinylmethyl)-N-methylamino] benzoic acid, and the distomer D-MTX is presented. The MEKC separation of these compounds was optimized by applying a step-by-step approach. The addition of beta-CD to a conventional MEKC system, based on sodium dodecyl sulfate (SDS) as surfactant, showed to be essential for the enantioresolution of racemic MTX as well as for the separation of the achiral impurities. To achieve high-resolution factor between the peaks adjacent to the main component (L-MTX), as required in the analysis of related impurities, the separation conditions were stressed; in particular, the addition of methanol to the CD-MEKC system resulted in a very effective choice. Under the optimized final conditions (100 mM SDS and 45 mM beta-CD in a mixture of 50 mM borate buffer, pH 9.30-methanol (75:25 v/v)), the method was validated showing a general adequate accuracy (93-106% recovery) in the determination of L-MTX related substances at the impurity level of 0.12% w/w with a relative standard deviation (RSD)% lower than 8% (n = 4). The method was successfully applied to the analysis of pharmaceuticals (tablets and injections) which showed to contain the distomer D-MTX as major impurity and aminopterine hydrate as a further related substance in the commercial tablets. PMID:15352016

  15. Hexafluoroisopropanol-modified cetyltrimethylammonium bromide/sodium dodecyl sulfate vesicles as a pseudostationary phase in electrokinetic chromatography.

    PubMed

    Tian, Yu; Li, Yunfang; Mei, Jie; Deng, Bin; Xiao, Yuxiu

    2015-07-24

    A novel catanionic surfactant vesicle system, formulated from hexafluoroisopropanol (HFIP), cetyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS), was developed as pseudostationary phase (PSP) in electrokinetic chromatography (EKC). HFIP, as an organic modifier with the prominent properties of ionization, hydrogen bond donor and hydrophobicity, was used to effectively promote the spontaneous vesicle formation from CTAB/SDS mixed aqueous solutions, where precipitates are easy to occur due to long carbon chains, and adjust the performance of CTAB/SDS vesicles. The physical features (size and viscosity) and electrophoretic parameters (electroosmotic mobility, electrophoretic mobility and elution range) of HFIP-modified CTAB/SDS vesicles were characterized as HFIP volume content (0-4%, v/v), CTAB/SDS molar ratio (2:8-7:3mol/mol) and total surfactant concentration (10-50mM) varying, respectively. The 3% v/v HFIP-modified CTAB/SDS (3:7mol/mol, 50mM) vesicle system proves to have the largest mean diameter (288.20nm) and the widest elution range (12.41), which is also much wider than that of the corresponding other four PSP systems including trifluoroethanol (TFE)-modified CTAB/SDS vesicles (5.69), isopropanol-modified CTAB/SDS micelles (2.03), HFIP-modified SDS micelles (4.86) and unmodified SDS micelles (3.12). The chromatographic performance of the HFIP-modified vesicle system was evaluated by separating eight polycyclic aromatic hydrocarbons, nitrotoluene positional isomers, five positively charged and five negatively charged/neutral drugs, respectively. Baseline or near-baseline separation was achieved for each series of solutes. Compared with the TFE-modified vesicle system, as well as the HFIP-modified and unmodified SDS micelle systems, the HFIP-modified vesicle system shows the best separation selectivity, the highest or comparable efficiency, and the lowest retention. PMID:26044380

  16. Electrokinetic Delivery of Single Fluorescent Biomolecules in Fluidic Nanochannels

    E-print Network

    Davis, Lloyd M.

    of the nanochannels by electrophoresis and/or electro-osmosis until they pass into a two-focus laser irradiation zone, or the photobleaching of the prior molecule. We have used computer simulations that include photophysical effects of the molecules along the channels [4,5]. In addition, nanochannels can simulate the crowded molecular environment

  17. Thermophysical and electrokinetic properties of nanofluids – A critical review

    Microsoft Academic Search

    S. M. S. Murshed; K. C. Leong; C. Yang

    2008-01-01

    In the past decade, nanofluids have attracted much interest because of their reported superior thermal performance and many potential applications. However, there are many inconsistencies in reported experimental results of the thermophysical properties such as the effective thermal conductivity of nanofluids and controversies in the underlying enhanced mechanisms. In this paper, various aspects of nanofluids including synthesis, potential applications, experimental

  18. Further studies of the metabolic incorporation and covalent binding of inhaled (/sup 3/H)- and (/sup 14/C)formaldehyde in Fischer-344 rats: effects of glutathione depletion

    SciTech Connect

    Casanova, M.; Heck Hd'

    1987-06-15

    Glutathione (GSH) is required for the oxidation of formaldehyde (HCHO) to formate catalyzed by formaldehyde dehydrogenase (FDH). The effects of GSH depletion on the mechanisms of labeling of macromolecules in the rat nasal mucosa and bone marrow by /sup 3/HCHO and H/sup 14/CHO were investigated. Male rats were exposed for 3 hr to atmospheres containing /sup 3/HCHO and H/sup 14/CHO at concentrations of 0.9, 2, 4, 6, or 10 ppm, 1 day after a single 3-hr preexposure to the same concentration of unlabeled HCHO. Two hours prior to the second exposure, the animals were injected either with phorone (300 mg/kg, ip) or with corn oil. The concentration of nonprotein sulfhydryls in the nasal respiratory mucosa of phorone-injected rats was decreased to 10% of that of corn oil-injected rats. The metabolic incorporation of /sup 3/HCHO and H/sup 14/CHO into DNA, RNA, and proteins in the respiratory and olfactory mucosa and bone marrow (femur) was significantly decreased, and DNA-protein crosslinking was significantly increased in the respiratory mucosa of phorone-injected relative to corn oil-injected rats at all HCHO concentrations. DNA-protein crosslinks were not detected in the respiratory mucosa of corn oil-injected rats at 0.9 ppm. Evidence was obtained for the formation of adducts of HCHO with the RNA from the nasal respiratory mucosa of phorone-injected rats at concentrations above 0.9 ppm. Covalent binding of HCHO to macromolecules in the bone marrow was not detected. These results indicate that the GSH-dependent oxidation of HCHO catalyzed by FDH is an important defense mechanism against the covalent reactions of HCHO with nucleic acids in the respiratory mucosa.

  19. Pinus taeda clones and soil nutrient availability: effects of soil organic matter incorporation and fertilization on biomass partitioning and leaf physiology.

    PubMed

    Tyree, Michael C; Seiler, John R; Maier, Chris A; Johnsen, Kurt H

    2009-09-01

    The combined effects of intensive management and planting of improved seedlings have led to large increases in productivity on intensively managed pine forests in the southeastern United States. To best match clones to particular site conditions, an understanding of how specific clones respond to changes in nutrition in terms of biomass partitioning, leaf physiology and biochemistry will be necessary. This study measured the response of biomass partitioning, light-saturated net photosynthesis (A(Sat)) and photosynthetic capacity to a range in soil fertility and fertilization between two contrasting Pinus taeda L. clone ideotypes: a 'narrow crown' clone (NC) that allocates more resources to stem growth and a 'broad crown' clone (BC) that allocates more resources to leaf area (LA). Under field conditions, we found consistent clone by environment (i.e., varying nutrient regimes) interactions in biomass as well as leaf physiology. Nutrient limitations induced by logging residue incorporation resulted in a 25% loss in stem growth in BC, while NC showed no response. We postulated that the decrease in BC was due to the differences in canopy architecture leading to a reduced canopy CO(2) assimilation, as well as to increased belowground maintenance costs associated with fine-root production. In contrast, N and P additions resulted in a 21% greater increase in stem volume in NC relative to BC. Fertilization increased A(Sat) temporarily in both clones, but A(Sat) eventually decreased below control levels by the end of the study. Although we found a clone by fertilization interaction in leaf physiology, the greatest genotype by environment interaction was found in the LA that appeared to have a greater influence than A(Sat) on growth. This research demonstrates the potential importance of selecting appropriate clonal material and silvicultural prescription when implementing site-specific silviculture to maximize productivity in intensively managed southern pine forests. PMID:19608598

  20. Boron incorporation into mullite

    NASA Astrophysics Data System (ADS)

    Griesser, K. J.; Beran, A.; Voll, D.; Schneider, H.

    2008-03-01

    Boron-doped mullites were synthesized using aluminium nitrate-nonahydrate, tetraethoxysilane and boric acid in a sol gel process with subsequent annealing at 950 and 1300 °C for five hours. Two different bulk compositions with constant Al2O3 contents (60 and 70 mol%, respectively) and varying SiO2 plus B2O3 contents were investigated. X-ray powder diffraction analyses yielded a linear decrease of the lattice parameters with increasing bulk B2O3 content, which was interpreted as to be due to boron incorporation. Related to the increasing boron content, corresponding infrared spectra revealed a slight and continuous shift for most of the absorption bands. These data show that mullite is able to incorporate large amounts of boron into its structure (up to about 20 mol% B2O3 depending on the bulk composition of the starting materials). Infrared analyses suggest that boron is incorporated into the mullite structure in form of planar three-fold coordinated BO3 groups.

  1. Electrokinetic Properties of Lipid and Sarcoplasmic Reticulum Membranes in Aqueous Electrolyte and in the Presence of Lipophilic Ions

    NASA Astrophysics Data System (ADS)

    Satterfield, Laura Elizabeth

    The purpose of this study is the characterization of the membrane-water interfaces of both sarcoplasmic reticulum membrane (SR) and charged lipid bilayers under varied properties of the surrounding aqueous solution. In this work we studied the electrokinetic properties of liposomes and SR vesicles as well as the interaction of lipophilic ions with these membranes. The study of electrokinetic properties is based on the measurements of electrophoretic mobility of SR membrane vesicles and PC/PG liposomes. Electrophoretic mobility of SR vesicles was measured as a function of ionic strength for six pH values (pH 4.0, 4.7, 5.0, 6.0, 7.5, and 9.0). Electrophoretic mobility of single-layered and multi-layered PC/PG liposomes was measured at neutral pH as a function of ionic strength. For interpretation of electrophoretic mobility studies, SR vesicles (at pH 4, 7, and 9) and multi-layered and single-layered liposome sizes were determined using photoelectron microscopy. The study of the interaction of lipophilic ions with these membranes is based on (1) measurements of their partition coefficients described in terms of an ion partition model based on the Langmuir adsorption model and (2) electrophoretic mobility measurements of SR vesicles and PC liposomes in suspension with varied concentration of lipophilic ions. SR-water and PC-water partition coefficients were measured as a function of concentration for two anions tetraphenylborate (TePB--) and pentabromophenol (PBP--) and two cations (Imipramine +, and Clomipramine+). The anions belong to a class of pesticides and the cations are drugs once prescribed as anti-depressants. Partition into the SR membrane was shown to be significantly greater for all lipophilic ions except TePB--, which only showed this effect at the higher lipophilic ion range of the data. The PC-water partition coefficient was also measured for TePP+. Since the lipid bilayer of SR is not significantly different than that of PC liposomes, we believe the differences in partition are due to excess lipophilic ions being absorbed to the proteins of SR. The electrokinetics of charged PCPG liposomes, and PC liposomes with absorbed lipophilic ions could be understood in terms of the charge being located below their surface and screened by counter-ions inside the polar head-group region. We call this model the "permeable surface model". The assumptions of this model are that (1) the charge exists on a plane at a depth, d, below the surface of the liposome within the lipid head-group region and (2) small ions (Na+, K+, Cl --) are able to penetrate the lipid head-group region with a molar membrane-water partition coefficient of 0.4. Using this model we were able to obtain the depth of sorption of lipophilic ions in PC liposomes. We found values of 0.13 nm for TePB--, 0.5 nm for PBP--, 0.12 nm for Imipramine+, 0.17 nm for Clomipramine and 0.25 nm for TePP+. The depth of lipophilic ions in PC is a valuable quantity for the study of the effect of lipophilic ions on membrane function. For PCPG mobility we found the charged plane due to PG lipids was 0.2 nm for single-layered liposomes and 0.1 nm for multi-layered liposomes. This is consistent with the relative size of PC and PG head groups The dependence of SR mobility on pH was found to be directly correlated with the total charge of the A, P, and N domains of the Ca2+-ATPase as determined by the amino acid residues and their corresponding pKa values in water. We found that detached charged plane model, a new model developed in our group, could be fit to the mobility of SR as a function of ionic strength while other soft particle models failed. The assumptions of this model are that (1) the friction caused by protruding proteins on the surface of SR can be represented by a homogeneous retardation layer of thickness D and softness parameter lambdaRL, and (2) the charge of the APN domain can be represented as a plane of charge embedded in the retardation layer at a distance s from the membrane surface. The best-fit values for lambda RL and s were not consistent for

  2. Origins of unintentional incorporation of gallium in InAlN layers during epitaxial growth, part II: Effects of underlying layers and growth chamber conditions

    NASA Astrophysics Data System (ADS)

    Kim, Jeomoh; Lochner, Zachary; Ji, Mi-Hee; Choi, Suk; Kim, Hee Jin; Kim, Jin Soo; Dupuis, Russell D.; Fischer, Alec M.; Juday, Reid; Huang, Yu; Li, Ti; Huang, Jingyi Y.; Ponce, Fernando A.; Ryou, Jae-Hyun

    2014-02-01

    We systematically study the origins and mechanisms for unintentional incorporation of gallium (Ga) during epitaxial growth of ternary InAlN thin-film layers. The origins of auto-incorporation of Ga have been investigated by using different underlying layers, regrown layers, and growth chamber conditions. It is shown that Ga-containing deposition on a wafer susceptor/carrier and on surrounding surfaces of uncooled parts in a growth chamber can be responsible for Ga in the InAl(Ga)N layers, while a GaN underlying layer below an InAl(Ga)N layer does not contribute to the auto-incorporation of Ga in the InAl(Ga)N layers. Especially, the Ga-containing deposition on the surfaces inside the chamber is believed to be the dominant source of auto-incorporated Ga, possibly due to the high vapor pressure of a liquid phase as a result of eutectic system formation between indium (In) and Ga. The pressure of liquid-phase Ga, pGa=~3.67×10-4 Torr, can be significant as compared to precursor partial pressures with pTMAl=3.7×10-4 Torr and pTMIn=2.4×10-5 Torr. In addition, magnesium (Mg) or magnesium precursor (Cp2Mg) in the growth chamber is shown to promote the auto-incorporation of Ga in the InAl(Ga)N layers.

  3. Efficient delivery to human lung fibroblasts (WI-38) of pirfenidone incorporated into liposomes modified with truncated basic fibroblast growth factor and its inhibitory effect on collagen synthesis in idiopathic pulmonary fibrosis.

    PubMed

    Togami, Kohei; Miyao, Aki; Miyakoshi, Kei; Kanehira, Yukimune; Tada, Hitoshi; Chono, Sumio

    2015-01-01

    In the present in vitro study, we assessed the delivery of pirfenidone incorporated into liposomes modified with truncated basic fibroblast growth factor (tbFGF) to lung fibroblasts and investigated the anti-fibrotic effect of the drug. The tbFGF peptide, KRTGQYKLC, was used to modify the surface of liposomes (tbFGF-liposomes). We used the thin-layer evaporation method, followed by sonication, to prepare tbFGF-liposomes containing pirfenidone. The cellular accumulation of tbFGF-liposomes was 1.7-fold greater than that of non-modified liposomes in WI-38 cells used as a model of lung fibroblasts. Confocal laser scanning microscopy showed that tbFGF-liposomes were widely localized in WI-38 cells. The inhibitory effects of pirfenidone incorporated into tbFGF-liposomes on transforming growth factor-?1 (TGF-?1)-induced collagen synthesis in WI-38 cells were evaluated by measuring the level of intracellular hydroxyproline, a major component of the protein collagen. Pirfenidone incorporated into tbFGF-liposomes at concentrations of 10, 30, and 100 µM significantly decreased the TGF-?1-induced hydroxyproline content in WI-38 cells. The anti-fibrotic effect of pirfenidone incorporated into tbFGF-liposomes was enhanced compared with that of pirfenidone solution. These results indicate that tbFGF-liposomes are a useful drug delivery system of anti-fibrotic drugs to lung fibroblasts for the treatment of idiopathic pulmonary fibrosis. PMID:25747986

  4. The electrokinetic behavior of calcium oxalate monohydrate in macromolecular solutions

    NASA Technical Reports Server (NTRS)

    Curreri, P. A.; Onoda, G. Y., Jr.; Finlayson, B.

    1988-01-01

    Electrophoretic mobilities were measured for calcium oxalate monohydrate (COM) in solutions containing macromolecules. Two mucopolysaccharides (sodium heparin and chrondroitin sulfate) and two proteins (positively charged lysozyme and negatively charged bovine serum albumin) were studied as adsorbates. The effects of pH, calcium oxalate surface charge (varied by calcium or oxalate ion activity), and citrate concentration were investigated. All four macromolecules showed evidence for chemical adsorption. The macromolecule concentrations needed for reversing the surface charge indicated that the mucopopolysacchrides have greater affinity for the COM surface than the proteins. The amount of proteins that can chemically adsorb appears to be limited to approximately one monomolecular layer. When the surface charge is high, an insufficient number of proteins can chemically adsorb to neutralize or reverse the surface charge. The remaining surface charge is balanced by proteins held near the surface by longer range electrostatic forces only. Citrate ions at high concentrations appear to compete effectively with the negative protein for surface sites but show no evidence for competing with the positively charged protein.

  5. Alternating current electrokinetic properties of gold-coated microspheres.

    PubMed

    García-Sánchez, Pablo; Ren, Yukun; Arcenegui, Juan J; Morgan, Hywel; Ramos, Antonio

    2012-10-01

    We present dielectrophoresis (DEP) and electrorotation (ROT) measurements of gold-coated polystyrene microspheres as a function of frequency and for several electrolyte conductivities. Particle rotation was counterfield with a maximum rotation rate observed at a single characteristic frequency. Negative DEP was observed for frequencies lower than this characteristic frequency and positive DEP for signal frequencies higher than this. These experimental observations are in agreement with predictions for the force and torque on the induced dipole of a perfectly polarizable metal sphere. We present a theoretical model for this case, and good agreement is found for both ROT and DEP measurements if we take into account the viscous friction for a spherical particle near a wall. From the characteristic frequency for rotation, we obtain the capacitance of the electrical double layer at the electrolyte-particle interface. Remarkably, no effect of induced charge electroosmosis around the particles can be inferred from DEP measurements. PMID:22931290

  6. Colloids in external electric and magnetic fields: Colloidal crystals, pinning, chain formation, and electrokinetics

    NASA Astrophysics Data System (ADS)

    Zhao, J.; Papadopoulos, P.; Roth, M.; Dobbrow, C.; Roeben, E.; Schmidt, A.; But, H.-J. t.; Auernhammer, G. K.; Vollmer, D.

    2013-11-01

    The motion of dilute and concentrated dispersions of colloids by external electric or magnetic fields is discussed. Electrokinetics is studied for colloids in confinement, where the confining walls can be flat or rough. As an example for a rough wall superhydrophobic surfaces are chosen. It is shown that the reduced friction at the water-air interface is insufficient to enhance electro-osmosis. Magnetic particles are pulled through a crystalline matrix formed by nonmagnetic colloids to investigate local melting and recrystallization of a crystalline matrix. The average strain field is calculated and the reorganization processes are compared to those induced by shear fields. Using single domain, magnetically blocked particles of different shape and surface characteristics, the interplay between particles, their environment and an external field is investigated.

  7. Boundary element modeling of electrokinetically driven fluid flow in two-dimensional microchannels.

    PubMed

    Hoyt, J J; Wolfer, W G

    1998-10-01

    In recent years there has been considerable interest in fabricating electrophoretic separation systems on microchips. In this study the boundary element method is used to numerically model both the electrical charge density and the electrokinetically driven fluid flow velocity field in two-dimensional microchannels containing an arbitrary configuration of circular flow obstacles. An estimate of both the average velocity and the resolution has been determined for various obstacle configurations, obstacle sizes, area fractions, surface line lengths per unit area and for different values of the thickness of the electrical double layer. Based on the results, an optimal microchannel design is suggested. In addition, the recently observed phenomenon of recirculated flow in an open region of an otherwise packed electrochromatography column has been confirmed with the numerical model. PMID:9820963

  8. Anti-Brownian ELectrokinetic (ABEL) Trapping of Single High Density Lipoprotein (HDL) Particles

    NASA Astrophysics Data System (ADS)

    Bockenhauer, Samuel; Furstenberg, Alexandre; Wang, Quan; Devree, Brian; Jie Yao, Xiao; Bokoch, Michael; Kobilka, Brian; Sunahara, Roger; Moerner, W. E.

    2010-03-01

    The ABEL trap is a novel device for trapping single biomolecules in solution for extended observation. The trap estimates the position of a fluorescently-labeled object as small as ˜10 nm in solution and then applies a feedback electrokinetic drift every 20 us to trap the object by canceling its Brownian motion. We use the ABEL trap to study HDL particles at the single-copy level. HDL particles, essential in regulation of ``good'' cholesterol in humans, comprise a small (˜10 nm) lipid bilayer disc bounded by a belt of apolipoproteins. By engineering HDL particles with single fluorescent donor/acceptor probes and varying lipid compositions, we are working to study lipid diffusion on small length scales. We also use HDL particles as hosts for single transmembrane receptors, which should enable study of receptor conformational dynamics on long timescales.

  9. Electrokinetic lab-on-a-biochip for multi-ligand/multi-analyte biosensing.

    PubMed

    Krishnamoorthy, Ganeshram; Carlen, Edwin T; deBoer, Hans L; van den Berg, Albert; Schasfoort, Richard B M

    2010-05-15

    We present a simple electrokinetic lab-on-a-biochip (EKLB) with four microchannels integrated with a surface plasmon resonance imaging (iSPR) label-free biosensor that is operated using a single electrical voltage for the simultaneous transport of reagents in all microchannels without conventional fluidic plumbing. We demonstrate the utility of the simple approach with various biosensing experiments, including single injection kinetics (multiple varied ligand densities and single analyte concentration), one shot kinetics (single ligand densities and multiple varied analyte concentrations), and multi-ligand/multianalyte detection. In all cases, the binding kinetics and affinity were extracted using a conventional 1:1 interaction model. Since the reagent transport is done with a single electrical voltage source, scaling up to hundreds to thousands of simultaneous experiments is straightforward. PMID:20402468

  10. Chiral separation of vinpocetine using cyclodextrin-modified micellar electrokinetic chromatography.

    PubMed

    Wan Ibrahim, Wan Aini; Abd Wahib, Siti Munirah; Hermawan, Dadan; Sanagi, Mohd Marsin; Aboul-Enein, Hassan Y

    2012-03-01

    A cyclodextrin-modified micellar electrokinetic chromatography (CD-MEKC) technique has been developed for enantioseparation of vinpocetine using an inexpensive 2-hydroxypropyl-?-CD (HP-?-CD) as the chiral selector (CS). The best chiral separation was achieved using 40 mM HP-?-CD as the CS in 50 mM phosphate buffer (pH 7.0) consisting of 40 mM sodium dodecyl sulfate (SDS) at a separation temperature and separation voltage of 25°C and 25 kV, respectively. To the author's best knowledge, this is the first CD-MEKC study able to successfully separate the four stereoisomer of vinpocetine in separation time of 9.5 min and resolution of 1.04-3.87. PMID:22271616

  11. Direct multicomponent analysis of beer samples constituents using micellar electrokinetic capillary chromatography.

    PubMed

    Cortacero-Ramírez, Sonia; Segura-Carretero, Antonio; Cruces-Blanco, Carmen; Hernáinz-Bermúdez de Castro, Miguel; Fernández-Gutiérrez, Alberto

    2004-06-01

    A capillary electrophoretic method was developed using micellar electrokinetic capillary chromatography (MEKC) with diode-array detection to analyze simultaneously 26 beer constituents in a single procedure, including alcohols, iso-alpha-acids, amino acids, flavonoids, isoflavonoids, a vitamin, purine and pyrimidine bases. After filtration, sample components were separated with an uncoated capillary and a 25 mM sodium borate and 110 mM SDS buffer at pH 10.5. Analyses were run at 14 kV and 8 s of hydrodynamic injection with UV detection at 210 nm and 270 nm. The proposed method was successfully applied to the direct determination of beer constituents without any sample cleanup procedures. PMID:15213986

  12. Numerical modeling of surface reaction kinetics in electrokinetically actuated microfluidic devices.

    PubMed

    Sadeghi, Arman; Amini, Younes; Saidi, Mohammad Hassan; Chakraborty, Suman

    2014-08-01

    We outline a comprehensive numerical procedure for modeling of species transport and surface reaction kinetics in electrokinetically actuated microfluidic devices of rectangular cross section. Our results confirm the findings of previous simplified approaches that a concentration wave is created for sufficiently long microreactors. An analytical solution, developed for the wave propagation speed, shows that, when normalizing with the fluid mean velocity, it becomes a function of three parameters comprising the channel aspect ratio, the relative adsorption capacity, and the kinetic equilibrium constant. Our studies also reveal that the reactor geometry idealized as a slit, instead of a rectangular shape, gives rise to the underestimation of the saturation time. The extent of this underestimation increases by increasing the Damkohler number or decreasing the dimensionless Debye-Hückel parameter. Moreover, increasing the values of the Damkohler number, the dimensionless Debye-Hückel parameter, the relative adsorption capacity, and the velocity scale ratio results in lower saturation times. PMID:25064245

  13. Improved lead recovery and sulphate removal from used lead acid battery through electrokinetic technique.

    PubMed

    Soundarrajan, C; Sivasankar, A; Maruthamuthu, S; Veluchamy, A

    2012-05-30

    This paper presents improvement in lead (Pb) recovery and sulphate removal from used Pb acid battery (ULAB) through Electrokinetic technique, a process aimed to eliminate environmental pollution that arises due to emission of gases and metal particles from the existing high temperature pyrometallurgical process. Two different cell configurations, (1) one with Nafion membrane placed between anode and middle compartments and Agar membrane between cathode and middle compartments and (2) another with only Agar membrane placed between both sides of the middle compartments were designed for the Pb and sulphate separation from ULAB. This paper concludes that the cell with only Agar membranes performed better than the cell with Nafion and Agar membranes in combinations and also explains the mechanism underlying the chemical and electrochemical processes in the cell. PMID:22483596

  14. Electrokinetic Energy Conversion in Nanofluidic Channels: Addressing the Loose Ends in Nanodevice Efficiency

    E-print Network

    Bakli, Chirodeep

    2014-01-01

    We bring out a non-trivial coupling of the intrinsic wettability, surface charge and electrokinetic energy conversion characteristics of nanofluidic devices. Our analyses demonstrate that nanofluidic energy conversion efficiencies may get amplified with increase in surface charge density, not perpetually, but only over a narrow regime of low surface charges, and may get significantly arrested to reach a plateau beyond a threshold surface charging condition, as attributed to a complex interplay between fluid structuration and ionic transport within a charged interfacial layer. We explain the corresponding findings from our molecular dynamics simulations with the aid of a simple modified continuum based theory. We attribute our findings to hitherto-unexplored four-way integration of surface charge, interfacial slip, ionic transport, and the water molecule structuration. The consequent complex non-linear nature of the energy transfer characteristics may bear far-ranging scientific and technological implications ...

  15. Electrokinetic Size and Mobility Traps for On-site Therapeutic Drug Monitoring.

    PubMed

    Shallan, Aliaa I; Guijt, Rosanne M; Breadmore, Michael C

    2015-06-15

    The extraction of target analytes from biological samples is a bottleneck in analysis. A microfluidic device featuring an electrokinetic size and mobility trap was formed by two nanojunctions of different pore size to extract and concentrate analytical targets from complex samples. The trap was seamlessly coupled with electrophoretic separation for quantitative analysis. The device was applied to the analysis of ampicillin levels in blood within 5?min and a linear response over the range of 2.5-20??g?mL(-1) . This covers the recommended levels for treating sepsis, a critical condition with 30 to 50?% mortality and unpredicted drug levels. The device provides a new opportunity for on-site therapeutic drug monitoring, which should enable quick and accurate dosing and may save lives in such critical conditions. PMID:25939633

  16. Capillary electrokinetic separations with optical detection. Technical progress report, February 1, 1994--January 31, 1995

    SciTech Connect

    Sepaniak, M.J.

    1995-05-01

    This multifarious research program is dedicated to the development of capillary electrokinetic separation techniques and associated optical methods of detection. Currently, research is directed at three general objectives. First, fundamental studies of pertinent separation and band broadening mechanisms are being conducted, with the emphasis on achieving rapid separations and understanding separation systems that include highly-ordered assemblies as running buffer additives. Second, instrumentation and methodologies associated with these capillary separation techniques are being advanced. Third, applications of these separation and detection systems should fill current voids in the capabilities of capillary separation techniques. In particular, it should be possible to perform rapid, highly efficient, and selective separations of hydrophobic compounds (e.g., higher MW polycyclic aromatic hydrocarbons (PAHs) and fullerenes), certain optical isomers, DNA fragments, and various pollutants including certain heavy metals.

  17. Determination of catechins in matcha green tea by micellar electrokinetic chromatography.

    PubMed

    Weiss, David J; Anderton, Christopher R

    2003-09-01

    Catechins in green tea are known to have many beneficial health properties. Recently, it has been suggested that matcha has greater potential health benefits than other green teas. Matcha is a special powdered green tea used in the Japanese tea ceremony. However, there has been no investigation to quantitate the catechin intake from matcha compared to common green teas. We have developed a rapid method of analysis of five catechins and caffeine in matcha using micellar electrokinetic chromatography. Results are presented for water and methanol extractions of matcha compared with water extraction of a popular green tea. Using a mg catechin/g of dry leaf comparison, results indicate that the concentration of epigallocatechin gallate (EGCG) available from drinking matcha is 137 times greater than the amount of EGCG available from China Green Tips green tea, and at least three times higher than the largest literature value for other green teas. PMID:14518774

  18. Electrophoretic concentration and sweeping-micellar electrokinetic chromatography analysis of cationic drugs in water samples.

    PubMed

    Wuethrich, Alain; Haddad, Paul R; Quirino, Joselito P

    2015-07-01

    Sample preparation by electrophoretic concentration, followed by analysis using sweeping-micellar electrokinetic chromatography, was studied as a green and simple analytical strategy for the trace analysis of cationic drugs in water samples. Electrophoretic concentration was conducted using 50mmol/L ammonium acetate at pH 5 as acceptor electrolyte. Electrophoretic concentration was performed at 1.0kV for 50min and 0.5kV and 15min for purified and 10-fold diluted waste water samples, respectively. Sweeping-micellar electrokinetic chromatography was with 100mmol/L sodium phosphate at pH 2, 100mmol/L sodium dodecyl sulfate and 27.5%-v/v acetonitrile as separation electrolyte. The separation voltage was -20kV, UV-detection was at 200nm, and the acidified concentrate was injected for 36s at 1bar (or 72% of the total capillary length, 60cm). Both purified water and 10-fold diluted waste water exhibited a linear range of two orders of concentration magnitude. The coefficient of determination, and intra- and interday repeatability were 0.991-0.997, 2.5-6.2, and 4.4-9.7%RSD (n=6), respectively, for purified water. The values were 0.991-0.997, 3.4-7.1, and 8.7-9.8%RSD (n=6), correspondingly, for 10-fold diluted waste water. The method detection limit was in the range from 0.04-0.09 to 1.20-6.97ng/mL for purified and undiluted waste water, respectively. PMID:26008596

  19. Are electro-kinetic methods useful in the development of tight gas and shale gas resources?

    NASA Astrophysics Data System (ADS)

    Glover, Paul W. J.

    2013-04-01

    The development of unconventional reservoirs provides new challenges to the petrophysicist; challenges that might be overcome with new techniques and approaches. The application of electro-kinetics to hydrocarbon reservoirs is relatively recent. In fact, up until 2012 there was no theoretical model that was capable of predicting the streaming potential coefficient of a rock with given petrophysical properties (Glover et al., 2012). Here, we use that model to ask the question whether the measurement of electro-kinetic properties of tight gas sands and gas shales could be useful in the development of these resources. We have calculated the streaming potential coefficient for gas shales with typical values of porosity, cementation exponent and grain size as a function of pore fluid salinity (10-5 to 2 mol/dm3) and pH (pH 5-9) at the temperatures and pressures encountered in shale gas reservoirs. For typical gas shales such as the Barnett shale (grain diameter 0.1 ? m, porosity 2.5 % and 5 ? D, respectively) the streaming potential coefficient is less than 2×10-10 V/Pa for all the modelled salinities and pHs. This is extremely small, and would only result in a streaming potential of the order of millivolts even during hydraulic fracturing at 10 kpsi, while deep monitoring of fluid flow would be impossible. Similar modelling of typical tight gas sands (grain diameter 3 ? m, porosity 5 %, permeability 0.1 mD) provides a higher streaming potential coefficients, reaching 10-7 V/Pa at low salinities (

  20. Electrokinetic delivery of single fluorescent biomolecules in fluidic nanochannels

    NASA Astrophysics Data System (ADS)

    Davis, Lloyd M.; Canfield, Brian K.; Li, Xiaoxuan; Hofmeister, William H.; Shen, Guoqing; Lescano-Mendoza, Isaac P.; Bomar, Bruce W.; Wikswo, John P.; Markov, Dmitry A.; Samson, Philip C.; Daniel, Claus; Sikorski, Zbigniew; Robinson, William N.

    2008-08-01

    We describe the fabrication of sub-100-nanometer-sized channels in a fused silica lab-on-a-chip device and experiments that demonstrate detection of single fluorescently labeled proteins in buffer solution within the device with high signal and low background. The fluorescent biomolecules are transported along the length of the nanochannels by electrophoresis and/or electro-osmosis until they pass into a two-focus laser irradiation zone. Pulse-interleaved excitation and time-resolved single-photon detection with maximum-likelihood analysis enables the location of the biomolecule to be determined. Diffusional transport of the molecules is found to be slowed within the nanochannel, and this facilitates fluidic trapping and/or prolonged measurements on individual biomolecules. Our goal is to actively control the fluidic transport to achieve rapid delivery of each new biomolecule to the sensing zone, following the completion of measurements, or the photobleaching of the prior molecule. We have used computer simulations that include photophysical effects such as triplet crossing and photobleaching of the labels to design control algorithms, which are being implemented in a custom field-programmable-gate-array circuit for the active fluidic control.