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1

Study of electrokinetic effects to quantify groundwater flow  

SciTech Connect

An experimental study of electrokinetic effects (streaming potential) in earth materials was undertaken. The objective was to evaluate the measurement of electrokinetic effects as a method of monitoring and predicting the movement of groundwater, contaminant plumes, and other fluids in the subsurface. The laboratory experiments verified that the electrokinetic effects in earth materials are prominent, repeatable, and can be described well to first order by a pair of coupled differential equations.

Brown, S.R. [Sandia National Lab., Albuquerque, NM (United States); Haupt, R.W. [MIT Lincoln Lab., Lexington, MA (United States)

1997-04-01

2

Electrokinetic Effects with Small Drops and Bubbles  

NASA Astrophysics Data System (ADS)

Electrokinetic effects with drops and bubbles are studied. We first examine the electrophoresis of drops and bubbles, computing the electrophoretic mobility as a function of the zeta-potential and several other parameters. We find drops and bubbles to be electrophoretically distinct from particles; e.g., conducting drops do not always migrate in the direction that would be anticipated from the sign of their surface charge. The analysis shows the sense of the migration is dictated by the net electrochemical stress acting along the interface and the zeta-potential alone is not sufficient to characterize the surface. For similar reasons, large inviscid spheres tend to remain stationary at modest zeta-potentials and, in contrast to rigid particles, their mobility is actually enhanced by polarization of the double layer. Further, we have uncovered conditions for which the mobility of nonconducting drops is insensitive to the interior viscosity. Next we examine the influence of partial dissociation of ionogenic solutes on electrophoresis, with a view toward understanding, how, and under what conditions, dissociation -association alters the electrokinetics. We find generally that mass-action resists polarization of the diffuse ion cloud and, so, is quantitatively important where double layer polarization and relaxation would otherwise prevail. Mass -action can reduce the mobility of a conducting drop by an order of magnitude, and sizeable decreases (50% and more) in drop mobility are even found at zeta -potentials below 50 mV. Rigid particles are affected less dramatically and quantitative effects rarely exceed 10%; particles are indifferent to partial ionization unless the zeta-potential is high (above ca. 100mV) and akappa > 1. Finally the influence of diffuse charge layers on electrically-induced drop deformations is investigated by revisiting the archetypal problem in electrohydrodynamics: the circulation produced in a drop by an electric field. Singular perturbation methods are employed to constuct a coherent physicochemical description of the regions proximal to the drop surface, including the space charge distribution. The electrokinetic model employed yields predictions of drop deformation consistent with the lumped parameter theory known as the 'leaky dielectric.' Previously it had been thought the leaky dielectric failed to account for the effects of diffuse charge layers on electrohydrodynamic flows.

Baygents, James Claude

3

Electrokinetic effects on detection time of nanowire biosensor  

NASA Astrophysics Data System (ADS)

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.

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

2012-04-01

4

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

SciTech Connect

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%.

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

2000-03-15

5

Ion-specific anomalous electrokinetic effects in hydrophobic nanochannels.  

PubMed

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. PMID:17501535

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

2007-04-27

6

Viscoelastic effects on electrokinetic particle focusing in a constricted microchannel.  

PubMed

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

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

2015-01-01

7

Charge-based particle separation in microfluidic devices using combined hydrodynamic and electrokinetic effects.  

PubMed

A new microfluidic approach for charge-based particle separation using combined hydrodynamic and electrokinetic effects is presented. A recirculating flow pattern is employed, generated through application of bi-directional flow in a narrow glass microchannel incorporating diverging or converging segments at both ends. The bi-directional flow in turn is a result of opposing pressure-driven flow and electro-osmotic flow in the device. Trapping and preconcentration of charged particles is observed in the recirculating flow, under conditions where the average net velocity of the particles themselves approaches zero. This phenomenon is termed flow-induced electrokinetic trapping (FIET). Importantly, the electrophoretic mobility (zeta potential) of the particles determines the flow conditions required for trapping. In this paper, we exploit FIET for the first time to perform particle separations. Using a non-uniform channel, one type of particle can be trapped according to its zeta-potential, while particles with higher or lower zeta-potentials are flushed away with the pressure-driven or electro-osmotic components, respectively, of the flow. This was demonstrated using simple mixtures of two polystyrene bead types having approximately the same size (3 microm) but different zeta potentials (differences were in the order of 25 to 40 mV). To gain more insight into the separation mechanism, particle separations in straight, 3 cm-long microchannels with uniform cross-section were also studied under conditions of bi-directional flow without trapping. A thorough theoretical analysis confirmed that trapping occurs when electrokinetic and pressure-driven particle velocities are equal and opposite throughout the diverging segment. This makes it possible to predict the pressure and electric field conditions required to separate particles having defined zeta potentials. PMID:19532967

Jellema, L C; Mey, T; Koster, S; Verpoorte, E

2009-07-01

8

Sub-Grid Modeling of Electrokinetic Effects in Micro Flows  

NASA Technical Reports Server (NTRS)

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.

Chen, C. P.

2005-01-01

9

The Effect of Constituent Metal Ions on the Electrokinetics of Chalcopyrite  

Microsoft Academic Search

Chalcopyrite in contact with water is thermodynamically unstable in the presence of oxygen. Oxidation of chalcopyrite may take place due to various factors, e.g., geological environment, mining\\/comminution, and storage. In this work oxidation of chalcopyrite has been investigated through interfacial electrokinetics. The characteristics of samples obtained from different geological locations as well as the effects of ageing and laboratory oxidation

Kalyan K. Das; Pradip; K. A. Natarajan

1997-01-01

10

Pumping based on transverse electrokinetic effects Irina Gitlin, Abraham D. Stroock, and George M. Whitesidesa)  

E-print Network

Pumping based on transverse electrokinetic effects Irina Gitlin, Abraham D. Stroock, and George M December 2002; accepted 19 June 2003 This work presents a strategy for microfluidic pumping based along the long axis is generated by an electric field applied across the channel. The pump operates

Prentiss, Mara

11

Enhanced remediation of Cr(VI)-contaminated soil by incorporating a calcined-hydrotalcite-based permeable reactive barrier with electrokinetics.  

PubMed

This paper describes the enhanced Cr(VI)-contaminated soil remediation via a combination of electrokinetics (EK) with a calcined-hydrotalcite-based permeable reactive barrier (PRB). First, this combination proved to be feasible, and remarkably facilitated Cr(VI) remediation in a column test. Then, lightly-to-severely (0.16-1.65 mg/g) Cr(VI)-contaminated soil was remediated in a simulated test with the calcined hydrotalcite as the PRB under an voltage of 10-30 V (i.e. an electric field intensity of 0.7-2.0 V/cm). The observations demonstrated that both PRB and EK are critical to efficient remediation and the high de-contamination efficiency is supposedly attributed to the synergistic effect, for which EK concentrates anionic chromate to the anode region and PRB media (calcined hydrotalcite) absorbs and immobilizes it. Thus we have shown that the combined PRB-EK system is highly adaptive and effective in remediation of a larger area contaminated with chromate and various anionic pollutants. PMID:22985820

Zhang, Jia; Xu, Yunfeng; Li, Wentao; Zhou, Jizhi; Zhao, Jun; Qian, Guangren; Xu, Zhi Ping

2012-11-15

12

Effects of soil composition on the removal of chromium by electrokinetics  

Microsoft Academic Search

Electrokinetic experiments were conducted on three different types of soil: glacial till, kaolin and Na-montmorillonite, in order to investigate the effect of soil mineralogy and naturally occurring hematite (Fe2O3) on the removal of chromium from these soils. Batch tests were also performed to characterize Cr(VI) adsorption onto these soils. This study has shown that soils which contain high carbonate buffers,

Krishna R. Reddy; Usha S. Parupudi; Srinivas N. Devulapalli; Charlie Y. Xu

1997-01-01

13

Physicochemical effects on uncontaminated kaolinite due to electrokinetic treatment using inert electrodes.  

PubMed

To determine the consequences of applying electrokinetics to clay soils, in terms of mechanisms acting and resulting effects on the clay, tests were conducted in which an electrical gradient was applied across controlled specimens of English China Clay (ECC) using 'inert' electrodes and a 'Reverse Osmosis' water feed to the electrodes (i.e., to mimic electrokinetic stabilisation without the stabiliser added or electrokinetic remediation without the contaminant being present). The specimens in which electromigration was induced over time periods of 3, 7, 14 and 28 days were subsequently tested for Atterberg Limits, undrained shear strength using a hand shear vane, water content, pH, conductivity and zeta potential. Water flowed through the system from anode to cathode and directly affected the undrained shear strength of the clay. Acid and alkali fronts were created around the anode and cathode, respectively, causing changes in the pH, conductivity and zeta potential of the soil. Variations in zeta potential were linked to flocculation and dispersion of the soil particles, thus raising or depressing the Liquid Limit and Plastic Limit, and influencing the undrained shear strength. Initial weakening around the anode and cathode was replaced by a regain of strength at the anode once acidic conditions had been created, while highly alkaline conditions at the cathode induced a marked improvement in strength. A novel means of indicating strength improvement by chemical means, i.e., free from water content effects, is presented to assist in interpretation of the results. PMID:18569290

Liaki, Christina; Rogers, Christopher D F; Boardman, David I

2008-07-01

14

Synergistic effects of bioremediation and electrokinetics in the remediation of petroleum-contaminated soil.  

PubMed

The present study evaluated the coupling interactions between bioremediation (BIO) and electrokinetics (EK) in the remediation of total petroleum hydrocarbons (TPH) by using bio-electrokinetics (BIO-EK) with a rotatory 2-D electric field. The results demonstrated an obvious positive correlation between the degradation extents of TPH and electric intensity both in the EK and BIO-EK tests. The use of BIO-EK showed a significant improvement in degradation of TPH as compared to BIO or EK alone. The actual degradation curve in BIO-EK tests fitted well with the simulated curve obtained by combining the degradation curves in BIO- and EK-only tests during the first 60 d, indicating a superimposed effect of biological degradation and electrochemical stimulation. The synergistic effect was particularly expressed during the later phase of the experiment, concurrent with changes in the microbial community structure. The community composition changed mainly according to the duration of the electric field, leading to a reduction in diversity. No significant spatial shifts in microbial community composition and bacterial numbers were detected among different sampling positions. Soil pH was uniform during the experimental process, soil temperature showed no variations between the soil chambers with and without an electric field. PMID:24613072

Guo, Shuhai; Fan, Ruijuan; Li, Tingting; Hartog, Niels; Li, Fengmei; Yang, Xuelian

2014-08-01

15

An assessment of the effectiveness and impact of electrokinetic remediation for pyrene-contaminated soil.  

PubMed

The effectiveness of electrokinetic remediation for pyrene-contaminated soil was investigated by an anode-cathode separated system using a salt bridge. The applied constant voltage was 24 V and the electrode gap was 24 cm. Two types of soil (sandy soil and loam soil) were selected because of their different conductive capabilities. The initial concentrations of pyrene in these soil samples were 261.3mg/kg sandy soil and 259.8 mg/kg loam soil. After treatment of the sandy soil and loam soil for seven days, 56.8% and 20.1% of the pyrene had been removed respectively. Under the same power supply voltage, the removal of the pollutant from the sandy soil was greater than that from the loam soil, due to the higher current and lower pH. Further analysis revealed that the effectiveness of electrokinetic remediation was affected by the energy expenditure, and was associated with changes in soil properties. PMID:25458684

Xu, Sujuan; Guo, Shuhai; Wu, Bo; Li, Fengmei; Li, Tingting

2014-11-01

16

Higher-order lattice Boltzmann simulation of energy conversion of electrokinetic nanobatteries  

NASA Astrophysics Data System (ADS)

As a novel green technology to harvest electric power, electrokinetic batteries appeal to more theoretical investigation in order to optimize their physical parameters, and hence to achieve higher energy conversion efficiency at nanoscales as expected. Generally, transport phenomena at nanoscales are out of the scope of continuum fluid mechanics theories. In addition, the electric double layer (EDL) requires a more comprehensive description incorporating image effect and ion size effect. In this study, the higher-order Lattice Boltzmann method (LBM) and the modified Poisson-Boltzmann theory (MPB) are used to investigate electrokinetic phenomena in nanochannels. Energy conversion is studied in terms of ion size, and dielectric properties of liquid and solid. 24.95% mechanical-electrical energy conversion efficiency may be achieved in a 16 nm electrokinetic battery. And hence about 6% mechanical energy can be utilized by the external load of the electrokinetic nanobattery.

Liu, Y.; Yang, J.

2009-04-01

17

Estimation of Joule heating effect on temperature and pressure distribution in electrokinetic-driven microchannel flows.  

PubMed

In this study we present simple analytical models that predict the temperature and pressure variations in electrokinetic-driven microchannel flow under the Joule heating effect. For temperature prediction, a simple model shows that the temperature is related to the Joule heating parameter, autothermal Joule heating parameter, external cooling parameter, Peclet number, and the channel length to channel hydraulic diameter ratio. The simple model overpredicted the thermally developed temperature compared with the full numerical simulation, but in good agreement with the experimental measurements. The factors that affect the external cooling parameters, such as the heat transfer coefficient, channel configuration, and channel material are also examined based on this simple model. Based on the mass conservation, a simple model is developed that predicts the pressure variations, including the temperature effect. An adverse pressure gradient is required to satisfy the mass conservation requirement. The temperature effect on the pressure gradient is via the temperature-dependent fluid viscosity and electroosmotic velocity. PMID:16380954

Chein, Reiyu; Yang, Yeong Chin; Lin, Yushan

2006-02-01

18

Electrokinetic effects in catalytic platinum-insulator Janus swimmers  

NASA Astrophysics Data System (ADS)

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.

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

2014-06-01

19

Electrokinetic Effects in Catalytic Pt-Insulator Janus Swimmers  

E-print Network

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.

Ebbens, S; Dunderdale, G; Howse, J R; Ibrahim, Y; Liverpool, T B; Golestanian, R

2013-01-01

20

Electrokinetic Effects in Catalytic Pt-Insulator Janus Swimmers  

E-print Network

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.

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

2013-12-21

21

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

E-print Network

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.

Rafael Roa; Félix Carrique; Emilio Ruiz-Reina

2012-08-01

22

Electrokinetic effect combined with surface-charge assumption: a possible generation mechanism of coseismic EM signals  

NASA Astrophysics Data System (ADS)

According to field observations, electromagnetic (EM) signals accompanying seismic waves can be recorded. The orders of magnitude of observed coseismic electric and magnetic signals associated with earthquakes are usually around 1 to 101 mV km-1 and 10-2 to 1 nT, respectively. In this paper, we carry out numerical simulation of coseismic EM signals associated with seismic waves due to electrokinetic effect and compare with field observations. The seismic source is represented by a finite fault measuring 15 × 9 km2 with a max slip displacement 1.5 m, corresponding to a Mw 5.9 earthquake. While using the EM surface boundary condition of continuous horizontal EM components, the magnetic signals only accompany the late-arriving S waves at receiver near the ground surface. This is obviously different from field observations. Thus, we adopt another EM surface boundary condition which assumes the ground surface carries surface charge. For the used half-space model, a surface-charge density magnitude |Qsc| in excess of 10-4 C m-2 is sufficient to make horizontal magnetic components clearly show up at the whole time duration of seismic waves. When |Qsc| increases, the contribution of surface-charge density to coseismic EM signals becomes more and more dominant comparing with that of the seismically induced streaming-current. We estimate the Qsc expected at the Earth's surface might be a value between -5 × 10-4 and -0.1 C m-2 by the comparison between numerical results and field observations. The vertical magnetic signals only accompany the late-arriving seismic waves, because they are theoretically only induced by SH wave. The field observation results of vertical magnetic signals may be resulted from the scattering effect or the seismic dynamo effect. We conclude that electrokinetic effect combined with surface-charge assumption is one possible generation mechanism of the observed coseismic EM signals.

Ren, Hengxin; Wen, Jian; Huang, Qinghua; Chen, Xiaofei

2015-02-01

23

Advanced electrokinetic characterization of composite porous membranes  

E-print Network

1 Advanced electrokinetic characterization of composite porous membranes Anthony Szymczyk* , Yonis. * Corresponding author, anthony.szymczyk@univ-rennes1.fr Abstract The effect of the streaming current flowing

Boyer, Edmond

24

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

NASA Astrophysics Data System (ADS)

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.

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

2004-12-01

25

Study of electromigration effects on a pH boundary during the on-line electrokinetic preconcentration by capillary electrophoresis.  

PubMed

A contribution to the description of electrokinetic effects on the pH boundary formed by sodium borate pH 9.5 and sodium phosphate pH 2.5 electrolytes for on-line preconcentration of weak acids is presented in this article. Simulations of electrokinetic injections together with experimental studies using contactless conductivity detection verified that the preconcentration is induced mainly by dissociation changes of analytes on the pH boundary and transient ITP state. Moreover, a study of the addition of organic solvent to the injection electrolyte was performed with impressive results. Subnanomolar LODs of hydroxybenzoic acids were achieved with 80% of methanol in the injection electrolyte which represents more than 70 000-fold preconcentration in comparison with classical CZE method. PMID:20737445

Vítková, Katerina; Petr, Jan; Maier, Vítezslav; Znaleziona, Joanna; Sevcík, Juraj

2010-08-01

26

Electrokinetic Power Generation from Liquid Water Microjets  

SciTech Connect

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%.

Duffin, Andrew M.; Saykally, Richard J.

2008-02-15

27

Depth-resolved detection of electrokinetic effects in cartilage using differential phase sensitive optical coherence tomography  

NASA Astrophysics Data System (ADS)

Osteoarthritis is a heterogeneous disease characterized by progressive loss of cartilage. The earliest biochemical features, which precede gross pathological changes, include non-uniform loss of proteoglycans associated with increase of water content in tissue and finally, fibrillation of the tissue's collagen network. Loss of proteoglycans decreases the ability of cartilage to withstand compressive loading and makes the tissue softer and more susceptible to wear and fibrilation. If the early loss of proteoglycans is detectable by a non-invasive optical technique, progression of the disease may be arrested using, for example, pharmacologic or surgical intervention. When an electric field is applied to cartilage by an electrical stimulator, the current-generated stress gradients are produced and stress deformation occurs. Since differential phase optical coherence tomography is very sensitive to subsurface stress deformation, we propose to stimulate cartilage electrically and detect stress gradients before gross signs of cartilage degeneration appear. Detection of depth-resolved electromechanical stress gradients in cartilage using differential phase optical coherence tomography may be useful to monitor non-invasively cartilage degeneration. Since the streaming potential and other electrokinetic effects in cartilage are directly proportional to proteoglycan density, application of an electric field in cartilage combined with depth-resolved phase sensitive optical measurements may provide a sensitive indicator of cartilage viability on the molecular-level.

Youn, Jong-In; Akkin, Taner; Wong, Brian J. F.; Peavy, George M.; Milner, Thomas E.

2003-06-01

28

ELECTROKINETIC SOIL PROCESSING COMPLICATING FEATURES OF ELECTROKINETIC REMEDIATION OF SOILS AND SLURRIES: SATURATION EFFECTS AND THE ROLE OF THE CATHODE ELECTROLYSIS  

Microsoft Academic Search

Electrokinetic soil processing is an emerging technology for decontamination of certain radionuclides, heavy metals, or organic species from soils or slurries. Tests reveal that the process efficiencies in partially saturated kaolinite samples (without contaminants) are high, since water supplied at the anode eventually flushed across the specimens and saturated the deposits. Consolidation settlements are expected in the vicinity of anodes

A. UGAZ; S. PUPPALA; R. J. GALE; Y. B. ACAR

1994-01-01

29

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

PubMed

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

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

2014-12-01

30

Effect of electrokinetics on the bioaccessibility of polycyclic aromatic hydrocarbons in polluted soils.  

PubMed

Bioaccessibility is one of the most relevant aspects to be considered in the restoration of soils using biological technologies. Polycyclic aromatic hydrocarbons (PAH) usually have residual fractions that are resistant to biodegradation at the end of the biological treatment. In some situations, these residual concentrations could still be above legal standards. Here, we propose that the available knowledge about electroremediation technologies could be applied to enhance bioremediation of soils polluted with PAH. The main objective of this study was to show that a previous electrokinetic treatment could reduce the PAH residual fractions when the soil is subsequently treated by means of a bioremediation process. The approach involved the electrokinetic treatment of PAH-polluted soils at a potential drop of 0.9 to 1.1 V/cm and the subsequent estimations of bioaccessibility of residual PAHs after slurry-phase biodegradation. Bioaccessibility of PAH in two creosote-polluted soils (clay and loamy sand, total PAH content averaging 300 mg/kg) previously treated with an electric field in the presence of nonionic surfactant Brij 35 was often higher than in untreated controls. For example, total PAH content remaining in clay soil after bioremediation was only 62.65 +/- 4.26 mg/kg, whereas a 7-d electrokinetic pretreatment had, under the same conditions, a residual concentration of 29.24 +/- 1.88 mg/kg after bioremediation. Control treatments without surfactant indicated that the electrokinetic treatment increased bioaccessibility of PAHs. A different manner of electric field implementation (continuous current vs. current reversals) did not induce changes in PAH bioaccessibility. We suggest that this hybrid technology may be useful in certain bioremediation scenarios, such as soils rich in clay and black carbon, which show limited success due to bioavailability restrictions, as well as in highly heterogeneous soils. PMID:21284296

Niqui-Arroyo, José-Luis; Ortega-Calvo, José-Julio

2010-01-01

31

Effects of electrokinetics and cationic surfactant cetyltrimethylammonium bromide [CTAB] on the hydrocarbon removal and retention from contaminated soils.  

PubMed

Hydrocarbon contaminated soil and groundwater is considered to be a leading cause for increased health risk and environmental contamination. Therefore, an efficient technique is needed to retard the movement or enhance the removal of the contaminant depending on the remediation objective. The goals of this study were to evaluate the impact of the addition of a cationic surfactant on the movement of hydrocarbons within a contaminated clay soil subjected to electrokinetic treatment. Water-flushing and surfactant-flushing experiments were conducted on one-dimensional soil columns. The model diesel fuel was composed of a mixture of benzene, toluene, ethylbenzene, xylenes [BTEX] and three selected polycyclic hydrocarbons [PAHs]. In the water-flushing experiments, the application of an electrokinetic treatment was found to enhance the removal of PAHs from the clay columns by about 20%. In contrast, the application of an electrokinetic treatment, when coupled with cationic surfactant-flushing, retarded the movement of BTEX and the three selected PAHs in the clay columns. Hydraulic columns with surfactant (CTAB) removed 17% more naphthalene and 11% more 2-methylnaphthalene compared to columns subjected to electrokinetic treatment with CTAB. The flux through the electrokinetic columns during water flushing as well as surfactant flushing was higher than the flux due to hydraulic gradient alone. As the solubility of hydrocarbons increased, they moved farther with electrokinetic treatment without CTAB. However, with CTAB the electrokinetic treatment tends to retard the movement. Use of a cationic surfactant coupled with electrokinetic treatment was found to retard the movement of contaminants. PMID:16894821

Ranjan, R Sri; Qian, Y; Krishnapillai, M

2006-07-01

32

Effect of a low-conductivity zone on field-amplified sample stacking in microchip micellar electrokinetic chromatography.  

PubMed

The effects of a low-conductivity (low-C) zone of an on-line sample preconcentration based on field-amplified sample stacking (FASS) under an acidic condition was investigated in microchip micellar electrokinetic chromatography (MCMEKC). By employing originally fabricated microchips with T- and cross-channel injectors on a single device, partial injection of the low-C zone and large-volume injection of a sample solution were demonstrated. As a typical result, the observed peak intensities of the fluorescent dyes were 1.5 - 2.0-fold enhanced by partial injection of the low-conductivity zone, as compared to those in FASS-MCMEKC without injecting the low-C zone; also, 30 - 40-fold enhancements of the detectability were achieved as compared to the conventional MCMEKC analyses. The resolutions of the hydrophobic analytes were also improved by introducing the low-C zone. The difference in the retention factors of model analytes in the high-C background and low-C zones was also estimated in order to clarify the effect of the low-C zone on the resolution and detectability in FASS-MCMEKC. PMID:23303098

Sueyoshi, Kenji; Kitagawa, Fumihiko; Otsuka, Koji

2013-01-01

33

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

SciTech Connect

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.

Collins, Y.E.

1987-01-01

34

Electrokinetic sample injection for high-sensitivity capillary zone electrophoresis (part 1): Effects of electrode configuration and setting.  

PubMed

Electrokinetic injection (EKI) is usually considered as one of the useful approaches to improve sensitivity of CZE analysis. In the present study, we explored the relationship between electrode position and sample amount injected during EKI process by using 2D computer simulation (CFD-ACE+) and real experiments, aiming to obtain higher detection sensitivity. Two different models of electrode configuration, a capillary inserted in a hollow electrode and a capillary surrounded by a cylindrical electrode on the reservoir wall, were simulated to evaluate the efficiency of EKI. It was found that analytes, occurring only in an effective potential field, could be introduced into the capillary while the other analytes remain outside of the field because of slow diffusion. Consequently, the longer distance between the electrode and the end of capillary, the higher efficiency of EKI was found by the simulation. This finding was verified by the real CZE analysis of dilute rare-earth metal ions in a chloride solution (pH almost neutral). In fact, when the distance of Pt electrode and the capillary end in a CE apparatus (an Otsuka CAPI-3100) was default (ca. 1 mm), LOD of Er was 0.27 microg/L. When the distance was increased to 19.5 mm, the LOD was improved over ten times down to 0.02 microg/L. The LOD achieved is 50-fold better than that of inductively coupled plasma atomic emission spectrometry (1-2 microg/L for Er). PMID:18850648

Hirokawa, Takeshi; Koshimidzu, Eiji; Xu, Zhongqi

2008-09-01

35

Electrokinetic decontamination of concrete  

Microsoft Academic Search

Concrete structures which have been contaminated with uranium and other radioisotopes may be decontaminated using in-situ electrokinetic remediation. By placing an electrode cell on the concrete surface and using the concrete`s rebar, a ground rod, or another surface cell as the counter electrode, the radioisotopes may be migrated from the concrete into this cell. The process is highly dependent upon

H. L. Lomasney; V. Yachmenev

1994-01-01

36

Electrokinetic improvement of offshore foundations  

NASA Astrophysics Data System (ADS)

Offshore and near-shore structures for energy exploration and production, harbour work and other facilities are often situated on very soft marine clay deposits that have shear strengths of a few kilopascals. The design of foundations embedded in these soft deposits often poses a challenge for geotechnical engineers, i.e., to satisfy the bearing capacity requirement, while at the same time minimizing the embedment depth and dimensions of the foundation due to cost considerations. The present study investigates the possibility of using electrokinetics to strengthen the soil adjacent to skirted foundations embedded in soft marine deposits and, thus, to improve the load carrying capacity of the foundations. The innovative feature of this approach as compared to soil improvement methods commonly adopted in practice is that the focus of strengthening is on the interface between the soil and embedded foundation, in terms of enhancement of adhesion and cementation. The thesis presents a summary of the method and results of a series of electrokinetic tests conducted on natural and simulated marine clays in small-scale and large-scale laboratory testing facilities. Steel plates and steel cylinders are used to simulate skirted foundations. A low dc voltage is applied via steel electrodes installed around the foundation models. The effects of electrokinetics are evaluated through changes in the geotechnical properties of the soil and load carrying capacities of the foundation model after treatment. The results demonstrate that the load carrying capacity of the skirted foundation model and the undrained shear strength of the adjacent soil increase by a factor of three after electrokinetic treatment. The clay adheres strongly to the inside and outside walls of the foundation model, indicating bonding occurs between the soil and steel after treatment. The treatment increases the soil undrained modulus and also induces a preconsolidation pressure of the remoulded clay, thereby reducing potential settlement of the foundation. The new technology described in this thesis has potential application in offshore engineering for increasing the load carrying capacity of skirted foundations installed in soft clayey sediments, as well as for rehabilitation of existing offshore structures.

Micic, Silvana

37

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

Microsoft Academic Search

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

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

2009-01-01

38

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

PubMed Central

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

Essa, Mohammed Hussain; Mu'azu, Nuhu Dalhat

2013-01-01

39

Electrokinetic Copper and Iron Migration in Anaerobic Granular Sludge  

Microsoft Academic Search

The application of low-level direct electric current (0.15 mA cm?2) as an electrokinetic technique to treat copper-contaminated mesophilic anaerobic granular sludge was investigated. The sludge was obtained from a full scale UASB reactor treating paper-mill wastewater and was artificially contaminated by Cu(NO3)2 or CuEDTA2? with initial copper concentrations of 1000 mg . kg?1 wet sludge. The effect of different electrokinetic

Jurate Virkutyte; Mika Sillanpää; Piet Lens

2006-01-01

40

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

Microsoft Academic Search

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 Iâ\\/I⁻ 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

Chris D. Cox; Matthew A. Shoesmith; Mriganka M. Ghosh

1996-01-01

41

Electrokinetic migration studies on removal of chromium and uranyl ions from 904-A trench soil  

SciTech Connect

This report describes a laboratory-scale study, in which electrokinetic migration technology was used to remove chromium and uranium, as well as other ions, from soil taken from a bore hole adjacent to the 904-A trench at the Savannah River Technology Center. Imposition of an electric current on humid (not saturated) soil successfully caused cations to migrate through the pore water of the soil to the cathode, where they were captured in an ISOLOCKTm polymer matrix and in a cation exchange resin incorporated in the polymer. Chemicals circulated through the anode/polymer and cathode/polymer were able to control pH excursions in the electrokinetic-cells by reacting with the H{sup +} and OH{sup {minus}} generated at the anode and cathode, respectively. The study indicates that ions adsorbed on the surface of the soil as well as those in the pores of soil particles can be caused to migrate through the soil to an appropriate electrode. After 10 days of operation at 20--25 V and 2 mA, approximately 65% of the chromium was removed from two 3.5 kg soil samples. A 57% removal of uranium was achieved. The study shows that electrokinetic migration, using the ISOLOCK{trademark} polymer will be effective as an in situ treatment method for the removal of metal ion contaminants in soil adjacent to the 904-A trench.

Bibler, J.P.; Meaker, T.F.; O`Steen, A.B.

1992-09-30

42

Hydroelectrical energy conversion in narrow confinements in the presence of transverse magnetic fields with electrokinetic effects  

Microsoft Academic Search

In this work, we investigate the combined influences of externally applied axial pressure gradients and transverse magnetic fields on hydroelectrical energy conversion mechanisms in narrow fluidic confinements. This energy conversion is achieved through an exploitation of the electromagnetohydrodynamic effects as a result of electrical double layer formation and the consequent interfacial phenomena. Although no electrical field is externally applied, a

Farooque Munshi; Suman Chakraborty

2009-01-01

43

Electrokinetics on superhydrophobic surfaces.  

PubMed

On a superhydrophobic surface a liquid is exposed to a large air-water interface. The reduced wall friction is expected to cause a higher electro-osmotic mobility. On the other hand, the low charge density of a superhydrophobic surface reduces the electro-osmotic mobility. Due to a lack of experimental data it has not been clear so far whether the reduced wall friction or the reduced charge density dominate the electrokinetic mobilities. To separate the relative contributions of electrophoresis and electro-osmosis, the mobilities of colloids on a negatively charged hydrophilic, a superhydrophobic (Cassie) and a partially hydrophilized superhydrophobic (Cassie composite) coating were measured. To vary the charge density as well as its sign with respect to those of the colloids the partially hydrophilized surfaces were coated with polyelectrolytes. We analyzed the electrokinetic mobilities of negatively charged polystyrene colloids dispersed in aqueous medium on porous hydrophilic and superhydrophobic surfaces by confocal laser scanning electron microscopy. In all cases, the external electric field was parallel to the surface. The total electrokinetic mobilities on the superhydrophobic (Cassie) and negatively charged partially hydrophilized (Cassie composite) surfaces were similar, showing that electro-osmosis is small compared to electrophoresis. The positively charged Cassie composite surfaces tend to 'trap' the colloids due to attracting electrostatic interactions and rough morphology, reducing the mobility. Thus, either the charge density of the coatings in the Cassie composite state or its slip length is too low to enhance electro-osmosis. PMID:23113983

Papadopoulos, Periklis; Deng, Xu; Vollmer, Doris; Butt, Hans-Jürgen

2012-11-21

44

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

SciTech Connect

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.

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

1997-05-01

45

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

PubMed

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 total organic carbon. The zeta potential of the unmodified and the organically modified clays was measured as a function of pH, and in all cases, became less negative as the total organic carbon was increased and as the length of the attached carbon chain was increased, indicating that the organic cations were more strongly bound within the particle's shear plane as total organic carbon content was increased. Measured zeta potential was also less negative for all clays tested (including unmodified montmorillonite) as pH was decreased. When compared on the basis of total organic carbon content, increasing the length of one carbon chain in the quaternary positions was a more effective method of neutralizing surface charge than was increasing the overall size of the cation (i.e., increasing the chain length in all quaternary positions). PMID:19963225

Bate, B; Burns, S E

2010-03-01

46

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...

47

Electrokinetic investigation of surfactant adsorption.  

PubMed

Fuerstenau [D.W. Fuerstenau, in: M.L. Hair (Ed.), Dekker, New York, 1971, p. 143] has already discussed the role of hydrocarbon chain of surfactants, the effect of alkyl chain length, chain structure and the pH of the solution on the adsorption process of surfactants. Later Kosmulski [M. Kosmulski, Chemical Properties of Material Surfaces, Surfactant Science Series, vol. 102, Dekker, New York, Basel, 2001] included the effect of surfactant concentration, equilibration time, temperature and electrolyte in his approaches. Certainly, the character of the head groups of the surfactant and the properties of the adsorbent surface are the basis for the adsorption process. Different surfactants and adsorbents cause different adsorption mechanisms described firstly by Rosen [M.J. Rosen, Surfactants and Interfacial Phenomena, second ed., Wiley, New York, 1989]. These adsorption mechanisms and their influencing factors were studied by electrokinetic investigations. Here only changes of the charges at the surfaces could be detected. To control the results of electrokinetic investigations they were compared with results from ellipsometric measurements. In the case of surfactant adsorption the chain length was vitally important. It could be shown by the adsorption of alkyl trimethyl ammonium bromides onto polymer films spin coated at wafer surfaces. The influence of the chain length depending on surface properties of the polymer film was studied. Streaming potential measurements were applied for these investigations. The obtained results enabled us to calculate the molar cohesive free energy per mol of CH2-group in the alkaline chain of the surfactant if all other specific adsorption effects were neglected. PMID:17335842

Bellmann, C; Synytska, A; Caspari, A; Drechsler, A; Grundke, K

2007-05-15

48

Competition between Dukhin's and Rubinstein's electrokinetic modes  

NASA Astrophysics Data System (ADS)

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.

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

2012-10-01

49

Electrokinetic transport in microchannels with random roughness  

SciTech Connect

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.

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

2008-01-01

50

Induced-charge electrokinetic phenomena  

E-print Network

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. ...

Bazant, Martin Z.

51

On the capabilities of nano electrokinetic thrusters for space propulsion  

NASA Astrophysics Data System (ADS)

A theoretical analysis considering the capabilities of nano electrokinetic thrusters for space propulsion is presented. The work describes an electro-hydro-dynamic model of the electrokinetic flow in nano-channels and represents the first attempt to exploit the advantages of the electrokinetic effect as the basis for a new class of nano-scale thrusters suitable for space propulsion. Among such advantages are their small volume, fundamental simplicity, overall low mass, and actuation efficiency. Their electrokinetic efficiency is affected by the slip length, surface charge, pH and molarity. These design variables are analyzed and optimized for the highest electrokinetic performance inside nano-channels. The optimization is done for power consumption, thrust and specific impulse resulting in high theoretical efficiency ˜99% with corresponding high thrust-to-power ratios. Performance curves are obtained for the electrokinetic design variables showing that high molarity electrolytes lead to high thrust and specific impulse values, whereas low molarities provide highest thrust-to-power ratios and efficiencies. A theoretically designed 100 nm wide by 1 ?m long emitter optimized using the ideal performance charts developed would deliver thrusts from 5 to 43 ?N, specific impulse from 60 to 210 s, and would have power consumption between 1-15 mW. It should be noted that although this is a detail analytical analysis no prototypes exist and any future experimental work will face challenges that could affect the final performance. By designing an array composed of thousands of these single electrokinetic emitters, it would result in a flexible and scalable propulsion system capable of providing a wide range of thrust control for different mission scenarios and maintaining very high efficiencies and thrust-to-power ratio by varying the number of emitters in use at any one time.

Diez, F. J.; Hernaiz, G.; Miranda, J. J.; Sureda, M.

2013-02-01

52

Electrokinetic remediation prefield test methods  

NASA Technical Reports Server (NTRS)

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.

Hodko, Dalibor (Inventor)

2000-01-01

53

dc electrokinetic transport of cylindrical cells in straight microchannels  

PubMed Central

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

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

2009-01-01

54

EMERGING TECHNOLOGY BULLETIN: ELECTROKINETIC SOIL PROCESSING  

EPA Science Inventory

Electrokinetic Soil Processing (or Electrokinetic Remediation) uses two series of electrodes (anodes and cathodes) positioned inside compartments that allow egress and ingress of pore fluids to the porous media. The compartments are filled with water or other process fluids and ...

55

Laboratory Experiment on Electrokinetic Remediation of Soil  

ERIC Educational Resources Information Center

Electrokinetic remediation is a method of decontaminating soil containing heavy metals and polar organic contaminants by passing a direct current through the soil. An undergraduate chemistry laboratory is described to demonstrate electrokinetic remediation of soil contaminated with copper. A 30 cm electrokinetic cell with an applied voltage of 30…

Elsayed-Ali, Alya H.; Abdel-Fattah, Tarek; Elsayed-Ali, Hani E.

2011-01-01

56

A macroion electrokinetics algorithm  

NASA Astrophysics Data System (ADS)

A numerical algorithm is presented for the standard model of macroion electrokinetics and certain generalizations of it. The macroion consists of a cylindrical section with identical, hemispheroidal endcaps, each piece having arbitrary length. The system of one macroion and adjoining salt solution is subjected to an arbitrary sequence of pulsed electrical fields and pulsed translational and rotational velocities. Numerical solutions are obtained for the time dependent electrostatic and mobile ion concentration fields and the solvent velocity. From these fields the dielectric response, force, and torque are calculated. Generalizations of the standard model include the diffusive motion of macroion surface charges, partial slip of solvent motion at the macroion surface, and a simple model for the reactive exchange of surface charge with solution ions. The primary illustrative application is to recent measurements of electric birefringence versus applied field frequency for poly-(tetrafluorothylene) colloidal particles, but a few results are presented for the dielectric response of DNA fragments and of spherical colloidal particles. The source code and additional details are provided as supplementary documentation.

Fixman, Marshall

2006-06-01

57

Electrokinetic high pressure hydraulic system  

DOEpatents

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.

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

2000-01-01

58

Electrokinetic Transport in Ionic Liquids  

E-print Network

A key difficulty in understanding electrokinetic transport in ionic liquids lies in the construction of an appropriate reference dynamics. The common assumption of modelling ion dynamics as a Langevin process is not warranted for solvent-free ionic liquids. The electrokinetic transport of ionic liquids obtained by coarse graining a simple exclusion process defined on a lattice is considered. The resulting dynamical equations can be written as a gradient flow with a degenerate mobility function. This form of the mobility function gives rise to charging behaviours that are different to the ones known in electrolytic solutions; the predicted behaviours agree qualitatively with the phenomenology observed in simulations.

Lee, Alpha A; Goriely, Alain

2015-01-01

59

Electrokinetic Transport in Ionic Liquids  

E-print Network

A key difficulty in understanding electrokinetic transport in ionic liquids lies in the construction of an appropriate reference dynamics. The common assumption of modelling ion dynamics as a Langevin process is not warranted for solvent-free ionic liquids. The electrokinetic transport of ionic liquids obtained by coarse graining a simple exclusion process defined on a lattice is considered. The resulting dynamical equations can be written as a gradient flow with a degenerate mobility function. This form of the mobility function gives rise to charging behaviours that are different to the ones known in electrolytic solutions; the predicted behaviours agree qualitatively with the phenomenology observed in simulations.

Alpha A. Lee; Dominic Vella; Alain Goriely

2015-02-13

60

Catalytically induced electrokinetics for motors and micropumps.  

PubMed

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

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

2006-11-22

61

Electrokinetically pumped high pressure sprays  

DOEpatents

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.

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

2002-01-01

62

Electrokinetically pumped high pressure sprays  

DOEpatents

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.

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

2005-11-01

63

Electrokinetic treatment of contaminated soils, sludges, and lagoons. Final report  

SciTech Connect

The electrokinetic process is an emerging technology for in-situ soil decontamination, in which chemical species, both ionic and nonionic are transported to an electrode site in soil. These products are subsequently removed from the ground via collection systems engineered for each specific application. Electrokinetics refer to movement of water, ions and charged particles relative to one another under the action of an applied direct current electric field. In a porous compact matrix of surface charged particles such as soil, the ion containing pore fluid may be made to flow to collection sites under the applied field. This report describes the effort undertaken to investigate electrokinetically enhanced transport of soil contaminants in synthetic systems. These systems consisted of clay or clay-sand mixtures containing known concentration of a selected heavy metal salt solution or an organic compound. Metals, surrogate radio nuclides and organic compounds evaluated in the program were representatives of those found at a majority of DOE sites. Degree of removal of these metals from soil by the electrokinetic treatment process was assessed through the metal concentration profiles generated across the soil between the electrodes. The best removals, from about 85 to 95% were achieved at the anode side of the soil specimens. Transient pH change had an effect on the metal movement via transient creation of different metal species with different ionic mobilities, as well as changing of the surface characteristics of the soil medium.

Wittle, J.K. [Electro-Petroleum, Inc., Wayne, PA (United States); Pamukcu, S. [Lehigh Univ., Bethlehem, PA (United States). Dept. of Civil Engineering

1993-04-01

64

Atomistic simulations of nanoscale electrokinetic transport  

NASA Astrophysics Data System (ADS)

An efficient and accurate algorithm for atomistic simulations of nanoscale electrokinetic transport will be described. The long-range interactions between charged molecules are treated using the Particle-Particle Particle-Mesh method and the Poisson equation for the electric potential is solved using an efficient multi-grid method in physical space. Using this method, we investigate two important applications in electrokinetic transport: electroosmotic flow in rough channels and electowetting on dielectric (EWOD). Simulations of electroosmotic and pressure driven flow in exactly the same geometries show that surface roughness has a much more pronounced effect on electroosmotic flow. Analysis of local quantities shows that this is because the driving force in electroosmotic flow is localized near the wall where the charge density is high. In atomistic simulations of EWOD, we find the contact angle follows the continuum theory at low voltages and always saturates at high voltages. Based on our results, a new mechanism for saturation is identified and possible techniques for controlling saturation are proposed.

Liu, Jin; Wang, Moran; Chen, Shiyi; Robbins, Mark

2011-11-01

65

Electrokinetic high pressure hydraulic system  

DOEpatents

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.

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

66

Electrokinetic high pressure hydraulic system  

DOEpatents

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.

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

2003-06-03

67

Electrokinetic decontamination of concrete. Final report, August 3, 1993--September 15, 1996  

SciTech Connect

The ELECTROSORB{reg_sign} {open_quotes}C{close_quotes} process is an electrokinetic process for decontaminating concrete. ELECTROSORB{reg_sign} {open_quotes}C{close_quotes} uses a carpet-like extraction pad which is placed on the contaminated concrete surface. An electrolyte solution is circulated from a supporting module. This module keeps the electrolyte solution clean. The work is advancing through the engineering development stage with steady progress toward a full scale demonstration unit which will be ready for incorporation in the DOE Large Scale Demonstration Program by Summer 1997. A demonstration was carried out at the Mound Facility in Miamisburg, Ohio, in June 1996. Third party verification by EG&G verified the effectiveness of the process. Results of this work and the development work that proceeded are described herein.

NONE

1998-12-31

68

The Multi-Porosity Multi-Permeability and Electrokinetic Natures of Shales and Their Effects in Hydraulic Fracturing of Unconventional Shale Reservoirs  

NASA Astrophysics Data System (ADS)

Imaging studies of unconventional shale reservoir rocks have recently revealed the multi-porosity multi-permeability nature of these intricate formations. In particular, the porosity spectrum of shale reservoir rocks often comprises of the nano-porosity in the organic matters, the inter-particle micro-porosity, and the macroscopic porosity of the natural fracture network. Shale is also well-known for its chemically active behaviors, especially shrinking and swelling when exposed to aqueous solutions, as the results of pore fluid exchange with external environment due to the difference in electro-chemical potentials. In this work, the effects of natural fractures and electrokinetic nature of shale on the formation responses during hydraulic fracturing are examined using the dual-poro-chemo-electro-elasticity approach which is a generalization of the classical Biot's poroelastic formulation. The analyses show that the presence of natural fractures can substantially increase the leak-off rate of fracturing fluid into the formation and create a larger region of high pore pressure near the fracture face as shown in Fig.1a. Due to the additional fluid invasion, the naturally fractured shale swells up more and the fracture aperture closes faster compared to an intrinsically low permeability non-fractured shale formation as shown in Fig.1b. Since naturally fractured zones are commonly targeted as pay zones, it is important to account for the faster fracture closing rate in fractured shales in hydraulic fracturing design. Our results also show that the presence of negative fixed charges on the surface of clay minerals creates an osmotic pressure at the interface of the shale and the external fluid as shown in Fig.1c. This additional Donnan-induced pore pressure can result in significant tensile effective stresses and tensile damage in the shale as shown in Fig.1d. The induced tensile damage can exacerbate the problem of proppant embedment resulting in more fracture closure and reduction of fracture length and productivity. The results also suggest that a fracturing fluid with appropriately designed salinity can minimize the chemically induced tensile damage and, thus, maximize the productivity from the created hydraulic fractures.

Liu, C.; Hoang, S. K.; Tran, M. H.; Abousleiman, Y. N.

2013-12-01

69

Electrokinetic dewatering of a phosphate clay  

Microsoft Academic Search

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

J. Q. Shang; K. Y. Lo

1997-01-01

70

Effect of thin oxide layers incorporated in spin valve structures  

NASA Astrophysics Data System (ADS)

The enhancement of the magnetoresistance effect, induced by incorporating nano-oxide layers (NOLs) in a bottom-type spin valve, was studied for various preparation conditions. The effect of a NOL in the Co90Fe10 pinned layer was found to depend critically on the oxygen pressure applied to form the thin oxide film. Pressures over 10-3 Torr O2 yield oxides thicker than about 0.7 nm, which apparently deteriorate the biasing field which exists over the oxide. The magnetoresistance values can further be raised by forming a specular reflecting oxide on top of the sense layer. Promising results were obtained with an Al2O3 capping layer formed in a solid-state oxidation reaction that occurs spontaneously when a thin Al layer is deposited on the oxidized surface of the Co90Fe10 sense layer.

Gillies, M. F.; Kuiper, A. E. T.; Leibbrandt, G. W. R.

2001-06-01

71

Removal of Mercury from Clayey Soils Using Electrokinetics  

Microsoft Academic Search

Numerous sites have been polluted with mercury as a result of accidental spills and improper disposal practices, and these mercury-contaminated sites may have adverse effects on human health and the environment. Innovative and cost-effective remediation techniques are urgently needed, and this study was performed to investigate the use of electrokinetics for mercury-contaminated soils. Initially, batch tests were performed on two

Krishna R. Reddy; Carlos Chaparro; Richard E. Saichek

2003-01-01

72

Electrokinetic Separation of Heavy Metals from Wastewater Treatment Sludge  

Microsoft Academic Search

In the study, a preliminary experiment on the removal of heavy metals from industrial wastewater sludge was carried out to evaluate the feasibility of electrokinetic separation. Four different types of processing fluid—tap water, ethylenediaminetetraacetic acid (EDTA), citric acid (CA), and 0.1 M nitric acid—were tested. EDTA was found to be the most effective agent within the set of chemicals tested for

Seon-Young Park; Geun-Yong Park; Do-Hyung Kim; Jung-Seok Yang; Kitae Baek

2010-01-01

73

Incorporating post-Newtonian effects in N-body dynamics  

NASA Astrophysics Data System (ADS)

The increasing role of general relativity in the dynamics of stellar systems with central massive black holes, in the generation of extreme mass-ratio inspirals and tidal disruption events, and in the evolution of hierarchical triple systems inspires a close examination of how post-Newtonian effects are incorporated into N-body dynamics. The majority of approaches incorporate relativity by adding to the Newtonian N-body equations the standard two-body post-Newtonian terms for a given star around the black hole or for the close binary in a triple system. We argue that, for calculating the evolution of such systems over time scales comparable to the relativistic pericenter advance time scale, it is essential to include "cross terms" in the equations of motion. These are post-Newtonian terms in the equation of motion of a given body that represent a coupling between the potential of the central black hole and the potential due to other stars in the system. For hierarchical triple systems, these are couplings between the potential of the inner binary and that of the distant third body. Over pericenter precession time scales, the effects of such terms can actually be "boosted" to amplitudes of Newtonian order. We write down the post-Newtonian N-body equations of motion including a central black hole in a truncated form that includes all the relevant cross terms, in a format ready to use for numerical implementation. We do the same for hierarchical triple systems, and illustrate explicitly the effects of cross terms on the orbit-averaged equations of evolution for the orbit elements of the inner binary for the special case where the third body is on a circular orbit. We also describe in detail the inspiration for this investigation: the seemingly trivial problem of the motion of a test body about a central body with a Newtonian quadrupole moment, including the relativistic pericenter advance, whose correct solution for the conserved total Newtonian energy requires including post-Newtonian cross terms between the mass monopole potential and the quadrupole potential.

Will, Clifford M.

2014-02-01

74

Effect of thin oxide layers incorporated in spin valve structures  

SciTech Connect

The enhancement of the magnetoresistance effect, induced by incorporating nano-oxide layers (NOLs) in a bottom-type spin valve, was studied for various preparation conditions. The effect of a NOL in the Co{sub 90}Fe{sub 10} pinned layer was found to depend critically on the oxygen pressure applied to form the thin oxide film. Pressures over 10{sup {minus}3}Torr O{sub 2} yield oxides thicker than about 0.7 nm, which apparently deteriorate the biasing field which exists over the oxide. The magnetoresistance values can further be raised by forming a specular reflecting oxide on top of the sense layer. Promising results were obtained with an Al{sub 2}O{sub 3} capping layer formed in a solid-state oxidation reaction that occurs spontaneously when a thin Al layer is deposited on the oxidized surface of the Co{sub 90}Fe{sub 10} sense layer. {copyright} 2001 American Institute of Physics.

Gillies, M. F.; Kuiper, A. E. T.; Leibbrandt, G. W. R.

2001-06-01

75

The effect of temperature, irradiance and animal size on incorporation rates of Simocephalus vetulus  

Microsoft Academic Search

Carbon incorporation rates of Simocephalus vetulus were measured to study the effects of the physical state of the animals, size of the animal, varying temperature and light conditions. Physical state of the animal showed little effect on incorporation rates after the first hour. Incorporation rates increased in proportion to the third power of animal size. Experimental animals collected at temperatures

L. Bevan; D. G. Wallen; J. M. Winner

1980-01-01

76

Enhancing the Efficiency of Electrokinetic Remediation through Technology Integration  

NASA Astrophysics Data System (ADS)

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.

Zhang, M.; Komai, T.

2009-12-01

77

Coupling bioleaching and electrokinetics to remediate heavy metal contaminated soils.  

PubMed

In this study, bioleaching was coupled with electrokinetics (BE) to remove heavy metals (Cu, Zn, Cr and Pb) from contaminated soil. For comparison, bioleaching (BL), electrokinetics (EK), and the chemical extraction method were also applied alone to remove the metals. The results showed that the BE method removed more heavy metals from the contaminated soil than the BL method or the EK method alone. The BE method was able to achieve metal solubilization rates of more than 70 % for Cu, Zn and Cr and of more than 40 % for Pb. Within the range of low current densities (<1 mA cm(-2)), higher current density led to more metal removal. However, the metal solubilization rates did not increase with increasing current density when the current density was higher than 1 mA cm(-2). Therefore, it is suggested that bioleaching coupled with electrokinetics can effectively remediate heavy metal-contaminated soils and that preliminary tests should be conducted before field operation to detect the lowest current density for the greatest metal removal. PMID:25680933

Huang, Qingyun; Yu, Zhen; Pang, Ya; Wang, Yueqiang; Cai, Zhihong

2015-04-01

78

Analysis of effects of impurities intentionally incorporated into silicon  

NASA Technical Reports Server (NTRS)

A methodology was developed and implemented to allow silicon samples containing intentionally incorporated impurities to be fabricated into finished solar cells under carefully controlled conditions. The electrical and spectral properties were then measured for each group processed.

Uno, F.

1977-01-01

79

Electrokinetics as a Propellantless Propulsion Source  

NASA Astrophysics Data System (ADS)

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.

Valone, Thomas

80

Electrokinetic properties of polymer colloids  

NASA Technical Reports Server (NTRS)

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.

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

1986-01-01

81

Electrokinetic focusing and filtration of cells in a serpentine microchannel  

E-print Network

Electrokinetic focusing and filtration of cells in a serpentine microchannel Christopher Church,1. This work presents a sheathless electrokinetic focusing of yeast cells in a planar serpentine microchannel via their differential electrokinetic focusing in a serpentine microchannel. © 2009 American Institute

Xuan, Xiangchun "Schwann"

82

Electrokinetic acceleration of DNA hybridization in microsystems.  

PubMed

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 350µm 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

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

2015-06-01

83

Incorporating long-term effects in determining the effectiveness of different types of online advertising  

Microsoft Academic Search

Although online advertising has become a full member of the marketing mix and is still growing in importance, studies of long-term,\\u000a or lagged, advertising effects have generally either neglected online advertising channels or have treated online advertising\\u000a as one homogeneous block. We analyze the short- and long-term effectiveness of different types of online advertising channels\\u000a by incorporating separate time lags

Ralph Breuer; Malte Brettel; Andreas Engelen

2011-01-01

84

Induced-Charge Electrokinetic Phenomena: Theory and Microfluidic Applications  

Microsoft Academic Search

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

Martin Z. Bazant; Todd M. Squires

2004-01-01

85

Rapid analysis of caffeine in ``smart drugs'' and ``energy drinks'' by microemulsion electrokinetic chromatography (MEEKC)  

E-print Network

Rapid analysis of caffeine in ``smart drugs'' and ``energy drinks'' by microemulsion electrokinetic 1. Introduction Caffeine is the most ancient and widely consumed psychoactive drug, being naturally in many cultures. The main effects of caffeine include physical endurance, reduction of fatigue

Miksik, Ivan

86

Quantitative determination of amygdalin epimers by cyclodextrin-modified micellar electrokinetic chromatography  

Microsoft Academic Search

A new capillary electrophoresis method was developed for the quantitative determination of the amygdalin epimers, amygdalin and neoamygdalin, which are biologically significant constituents in the crude drugs, namely Persicae Semen and Armeniacae Semen. The effects of surfactants, additives and other analytical parameters were studied. As a result, the resolution of two epimers was performed by cyclodextrin-modified micellar electrokinetic chromatography with

Takafumi Isozaki; Yutaka Matano; Keiichi Yamamoto; Noboru Kosaka; Tadato Tani

2001-01-01

87

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

ERIC Educational Resources Information Center

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…

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

2011-01-01

88

Incorporating Conservation Zone Effectiveness for Protecting Biodiversity in Marine Planning  

PubMed Central

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

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

2013-01-01

89

Ph.D. Thesis Electrokinetics and catalysis  

E-print Network

of the flow direction has been detected. No existing electrokinetic models published in the liter- ature are able to account quantitatively for this observation. The impedance spectra of these pumps have of topology optimization on ICEO systems. This numerical op- timization method has been implemented

90

Electrokinetic ion transport through unsaturated soil  

Microsoft Academic Search

Results of a field demonstration of electrokinetic transport of acetate through an unsaturated heterogeneous soil are compared to numerical modeling predictions. The numerical model was based on the groundwater flow and transport codes MODFLOW and MT3D modified to account for electrically induced ion transport. The 6-month field demonstration was conducted in an unsaturated layered soil profile where the soil moisture

Earl D Mattson; Robert S Bowman; Eric R Lindgren

2002-01-01

91

Electrokinetics for control of on-chip chemical reactions.  

NASA Astrophysics Data System (ADS)

It is well known that electrokinetics affords precise control over flow and species transport in microfluidic systems through simple manipulation of externally applied electric potentials. In this work it is demonstrated how electrokinetic effects can be extended to provide simultaneous control over on-chip chemical reactions through manipulation of the local thermal (ohmic/joule heating), shear (electroosmosis) and electrical (electrophoresis) energies at the reaction site. The coupling of the electrical, flow and ``whole-chip'' thermal effects in both the fluidic and substrate domains are investigated through extensive finite element simulations and experimentally validated using microscale fluorescence thermometry. The simulations reveal changes in viscosity and local conductivity on the order of 50% induced by changes in the fluidic geometry. General chip design guidelines for maximizing or minimizing these effects will also be discussed. The degree of precision available and clinical utility of the technique is demonstrated through the detection of a single base pair mutation (single nucleotide polymorphism) in a DNA microarray integrated into a PDMS/glass microfluidic chip.

Erickson, David; Venditti, Roberto

2005-03-01

92

Electrokinetic migration studies on removal of chromium and uranyl ions from 904-A trench soil  

SciTech Connect

This report describes a laboratory-scale study, in which electrokinetic migration technology was used to remove chromium and uranium, as well as other ions, from soil taken from a bore hole adjacent to the 904-A trench at the Savannah River Technology Center. Imposition of an electric current on humid (not saturated) soil successfully caused cations to migrate through the pore water of the soil to the cathode, where they were captured in an ISOLOCKTm polymer matrix and in a cation exchange resin incorporated in the polymer. Chemicals circulated through the anode/polymer and cathode/polymer were able to control pH excursions in the electrokinetic-cells by reacting with the H[sup +] and OH[sup [minus

Bibler, J.P.; Meaker, T.F.; O'Steen, A.B.

1992-09-30

93

Microsystem for field-amplified electrokinetic trapping preconcentration of DNA at poly(ethylene terephthalate) membranes.  

PubMed

In electrokinetic trapping (EKT), the electroosmotic velocity of a buffer solution in one area of a microfluidic device opposes the electrophoretic velocity of the analyte in a second area, resulting in transport of DNA to a location where the electrophoretic and electroosmotic velocities are equal and opposite and DNA concentrates at charged nanochannels. The method does not require an optical plug localization, a considerable advantage as compared to preconcentration techniques previously presented. In the work reported here, the trapping process is preceded by a field-amplification in the sample reservoir to reduce trapping time, as field-amplified EKT is shown to be an effective technique to preconcentrate samples from larger volumes. A theoretical model explaining the principle of field-amplified EKT considers different ionic strengths and cross-sectional areas in the microchip segments. The model is supported by experimental data using nucleic acids and fluorescein as sample analytes. An incorporated poly(ethylene terephthalate) (PET) membrane provides anion exclusion due to a negatively charged surface. A fluidic counter flow supports the trapping process in 100 nm pores due to anion exclusion. An analysis of Joule heating gives evidence that temperature gradient focusing effects are negligible and charge exclusion is responsible for trapping. The theoretical model developed and experimentally demonstrated can be exploited for the preconcentration of cell free fetal DNA circulating in maternal plasma and other rare nucleic acid species present in large sample volumes. PMID:19296594

Hahn, Thomas; O'Sullivan, Ciara K; Drese, Klaus S

2009-04-15

94

Pore network model of electrokinetic transport through charged porous media.  

PubMed

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

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

2014-04-01

95

The transport behavior of As, Cu, Pb, and Zn during electrokinetic remediation of a contaminated soil using electrolyte conditioning.  

PubMed

Electrokinetic remediation (also known as electrokinetics) is a promising technology for removing metals from fine-grained soils. However, few studies have been conducted regarding the transport behavior of multi-metals during electrokinetics. We investigated the transport of As, Cu, Pb, and Zn from soils during electrokinetics, the metal fractionation before and after electrokinetics, the relationships between metal transport and fractionation, and the effects of electrolyte conditioning. The main transport mechanisms of the metals were electroosmosis and electromigration during the first two weeks and electromigration during the following weeks. The direction of electroosmotic flow was from the anode to the cathode, and the metals in the dissolved and reducible-oxides fractions were transported to the anode or cathode by electromigration according to the chemical speciation of the metal ions in the pore water. Moreover, a portion of the metals that were initially in the residual fraction transitioned to the reducible and soluble fractions during electrokinetic treatment. However, this alteration was slow and resulted in decreasing metal removal rates as the electrokinetic treatment progressed. In addition, the use of NaOH, H3PO4, and Na2SO4 as electrolytes resulted in conditions that favored the precipitation of metal hydroxides, phosphates, and sulfates in the soil. These results demonstrated that metal removal was affected by the initial metal fractionation, metal speciation in the pore solution, and the physical-chemical parameters of the electrolytes, such as pH and electrolyte composition. Therefore, the treatment time, use of chemicals, and energy consumption could be reduced by optimizing pretreatment and by choosing appropriate electrolytes for the target metals. PMID:24972074

Yang, Jung-Seok; Kwon, Man Jae; Choi, Jaeyoung; Baek, Kitae; O'Loughlin, Edward J

2014-12-01

96

Heavy metal removal from shooting range soil by hybrid electrokinetics with bacteria and enhancing agents.  

PubMed

This study presents a method for heavy metal removal from a shooting range soil by a newly suggested hybrid technology. Active bioaugmentation was performed using Acidithiobacillus thiooxidans in the bioleaching step, and each test was sequentially combined with acid-enhanced and EDTA-enhanced electrokinetics. The results of the bioleaching processes indicated that S-oxidizing bacteria enhanced the mobility of heavy metals in the soil, based on their chemical forms. This process improved the final removal efficiencies of Cu and Zn in the hybrid electrokinetics. In the case of Pb, however, anglesite (PbSO(4)) has been easily formed in the bioleaching step from sulfate, a byproduct of S oxidation. Despite the potential negative effect on combining acid-enhanced electrokinetics, this problem was overcome by the application of an electrokinetic EDTA injection. Moreover, this method showed enhanced removal efficiency for Pb (92.7%) that was superior to that of an abiotic process. This hybrid method of EDTA-enhanced bioelectrokinetics demonstrated an adequate removal efficiency of heavy metals, especially Pb, with lower power consumption and eco-friendly soil conditions. PMID:21090604

Lee, Keun-Young; Kim, Kyoung-Woong

2010-12-15

97

Effectively incorporating selected multimedia content into medical publications  

PubMed Central

Until fairly recently, medical publications have been handicapped by being restricted to non-electronic formats, effectively preventing the dissemination of complex audiovisual and three-dimensional data. However, authors and readers could significantly profit from advances in electronic publishing that permit the inclusion of multimedia content directly into an article. For the first time, the de facto gold standard for scientific publishing, the portable document format (PDF), is used here as a platform to embed a video and an audio sequence of patient data into a publication. Fully interactive three-dimensional models of a face and a schematic representation of a human brain are also part of this publication. We discuss the potential of this approach and its impact on the communication of scientific medical data, particularly with regard to electronic and open access publications. Finally, we emphasise how medical teaching can benefit from this new tool and comment on the future of medical publishing. PMID:21329532

2011-01-01

98

Sensitive enantioseparation by transient trapping-cyclodextrin electrokinetic chromatography.  

PubMed

An on-line sample preconcentration based on transient trapping was applied to cyclodextrin electrokinetic chromatography (CDEKC) to realize a highly sensitive chiral analysis in capillary electrophoresis. The partial introduction of a micellar solution before the electrokinetic injection of a sample solution provided the effective preconcentration and enantioseparation of chiral compounds, resulting in the up to 240-fold enhancements of peak intensity and 100-fold improvements of limit of detection of (R),(S)-1-aminoindan as the model analyte. The demonstrated method could be applied to the other pharmaceutical compounds, which allowed five chiral analytes to be resolved with 40- to 160-fold sensitivity enhancements at once. The enantioseparation efficiency of the proposed method was slightly lower as compared to the conventional CDEKC, while the acceptable baseline separations of enantiomers were obtained in transient trapping-CDEKC relative to the undesirable resolution in the CDEKC with other preconcentration techniques. Additionally, it was clarified that transient trapping-CDEKC was also applicable to the analysis of enantiomeric excess, providing the sensitive detection of 43ppb of (R)-chlorpheniramine in 5ppm (S)-chlorpheniramine solution commercially available. PMID:22959845

Sueyoshi, Kenji; Koino, Hiroshi; Kitagawa, Fumihiko; Otsuka, Koji

2012-12-21

99

The effect of dopant incorporation on the elastic properties of Ti metal  

NASA Astrophysics Data System (ADS)

The effect of dopant atoms on the structural and elastic properties of ? titanium is examined through the use of density functional theory. The effect of 66 dopant atoms, from H through the third row transition metal elements, were considered in this study. In all cases the dopant concentration was approximately 3 at%, with substitutional incorporation investigated for all atoms considered and interstitial incorporation investigated for a smaller subset of elements. Interstitial incorporation was calculated to be more energetically favourable for the elements H, B to F, S and Cl with these dopants coordinating octahedrally with the surrounding Ti atoms, while substitutional incorporation was found to be more stable for the other elements. The five independent single crystal elastic constants are calculated, along with the bulk and shear moduli. The energetics and mechanically stability associated with the alloying of various dopants is also discussed.

Wilson, N. C.; McGregor, K.; Gibson, M. A.; Russo, S. P.

2015-01-01

100

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

NASA Astrophysics Data System (ADS)

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.

Masi, Matteo; Pazzi, Veronica; Losito, Gabriella

2013-04-01

101

Short-term effects of cover crop incorporation on soil carbon pools and nitrogen availability  

Microsoft Academic Search

Winter cover crops are increasingly used to maintain water quality and\\u000a agoecosystem productivity. Cover crop incorporation influences transient\\u000a soil microbial dynamics and nutrient availability at an early growth\\u000a stage of subsequent crops. Short-term (less than or equal to 35 d)\\u000a effects of cover crop incorporation on soil C pools and N availability\\u000a were evaluated using sandy loam soils from organically

S Hu; NJ Grunwald; AHC vanBruggen; GR Gamble; LE Drinkwater; C Shennan; MW Demment

1997-01-01

102

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

NASA Astrophysics Data System (ADS)

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.

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

2015-05-01

103

Electrokinetic properties of the mammalian tectorial membrane  

PubMed Central

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

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

2013-01-01

104

In situ soil remediation using electrokinetics  

SciTech Connect

Electrokinetics is emerging as a promising technology for in situ soil remediation. This technique is especially attractive for Superfund sites and government operations which contain large volumes of contaminated soil. The approach uses an applied electric field to induce transport of both radioactive and hazardous waste ions in soil. The transport mechanisms include electroosmosis, electromigration, and electrophoresis. The feasibility of using electrokinetics to move radioactive {sup 137}Cs and {sup 60}Co at the Hanford Site in Richland, Washington, is discussed. A closed cell is used to provide in situ measurements of {sup 137}Cs and {sup 60}Co movement in Hanford soil. Preliminary results of ionic movement, along with the corresponding current response, are presented.

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

1994-11-01

105

Manipulating bacteria with opto-electrokinetic methods  

NASA Astrophysics Data System (ADS)

Recently we developed an opto-electrokinetic method for manipulating particles and cells called Rapid Electrokinetic Patterning (REP). REP is a very fast method for manipulating thousands of particles simultaneously and controllably owing to the creation of an electrothermal vortex that transports particles rapidly and in parallel to a site determined by the focal point of a laser beam. Whether particles are trapped at the center of the vortex or not is determined by their electrical properties (conductivity and permittivity). In this talk we demonstrate that REP can be used to manipulate the bacterium Shewanella oneidensis MR-1. The bacteria are assembled into large planar arrays of organisms. The dependence of this assembly process on voltage and frequency is quantified. REP can even be used to selectively manipulate and collect live or dead bacteria.

Wereley, Steve; Kwon, Jae-Sung; Ravindranath, Sandeep; Irudayaraj, Joseph

2010-11-01

106

Quartz Channel Fabrication for Electrokinetically Driven Separations  

SciTech Connect

For well resolved electrokinetic separation, we L tilize crystalline quartz to micromachine a uniformly packe Q&iKLmnel. Packing features are posts 5 Vm on a side with:} pm spacing and etched 42 Vm deep. In addition to anisotropic wet etch characteristics for micromachining, quartz propmties are compatible with chemical soiutioits, ekctrokinetic high voltage operation, and stationary phase film depositions. To seal these channels, we employ a room temperature silicon-oxynhride deposition to forma membrane, that is subsequently coated for mechanical stability. Using this technique, particulate issues and global warp, that make large area wafer bon ding methods difficult, are avoided, and a room temperature process, in contrast to high temperature bonding techniques, accommodate preprocessing of metal films for electrical interconnect. After sealing channels, a number of macro-assembly steps are required to attach a micro-optical detection system and fluid interconnects. Keywords: microcharmel, integrated channel, micromachined channel, packed channel, electrokinetic channel, eleetrophoretic channel

Arnold, D.W.; Ashby, C.I.H.; Bailey, C.G.; Kravitz, S.H., Warren, M.E.; Matzke, C.M.

1998-12-01

107

Electrokinetic and Thermodynamic Analysis of the Dyeing Process of Polyamide Fabric with Mordant Black 17.  

PubMed

An electrokinetic and thermodynamic analysis of the dyeing process of polyamide 6.6 (nylon 6.6) by the dye Palatine chrome black (PCB) is described in the present work. The electrokinetic study was performed by means of electrophoretic mobility measurements on bare and dyed fiber. The most significant result is the increase in electrokinetic potential, zeta, toward more negative values as the dye concentration in the dispersion medium is raised. Given the molecular structure of PCB, which contains a sulfonate group per molecule, it is feasible that such increase in |zeta| is due to the adsorption of the negatively charged, dissociated dye entities. The uptake of PCB by the fiber is experimentally determined at two temperatures: the strong increase in the amount of dye incorporated into the fiber as the initial concentration of PCB is larger, and also the fact that higher temperatures favor the dyeing process is an indication of the existence of strong interactions between both interfaces. From a different point of view, the efficient coverage of Nylon by PCB is also demonstrated by the changes experienced by the surface free energy of Nylon upon treatment with PCB. Copyright 2001 Academic Press. PMID:11350132

Espinosa-Jiménez, M.; Perea-Carpio, R.; Padilla-Weigand, R.; Ontiveros, A.

2001-06-01

108

Electrokinetic Phenomena in Homogeneous Cylindrical Pores  

Microsoft Academic Search

The electrokinetic phenomena occurring in homogeneous cylindrical pores containing symmetric electrolytes are studied. The local relations for flow in the pores (Nernst–Planck and Navier–Stokes equations) are developed. The analysis includes a numerical solution of the nonlinear Poisson–Boltzmann equation. The integral expressions of the phenomenological coefficients coupling the solvent flow and the electrical current with the hydrostatic pressure and the electrical

Anthony Szymczyk; Boujemaa Aoubiza; Patrick Fievet; Jacques Pagetti

1999-01-01

109

Ion Irradiation Effects in Synthetic Garnets Incorporating Actinides Satoshi Utsunomiya1  

E-print Network

Ion Irradiation Effects in Synthetic Garnets Incorporating Actinides Satoshi Utsunomiya1 , Lu the long term radiation effects due to radioactive decay can be simulated in short term with heavy ion-irradiation[3], many irradiation experiments using heavy ions have been completed in the potential ceramics

Utsunomiya, Satoshi

110

Properties and electrokinetic behavior of non-dilute colloidal suspensions  

Microsoft Academic Search

This paper is a critical review of how the fluid properties (e.g., density, viscosity, conductivity, and permittivity) and behaviors (e.g., electrophoretic motion, electrokinetic aggregation, chaining, and instabilities) depend on colloid volume fraction. The review focuses on electrokinetic flows in aqueous solutions with suspensions on the order of a few percent that are not considered concentrated, yet may exhibit several behaviors

Jonathan D. Posner

2009-01-01

111

FEASIBILITY OF ELECTROKINETIC SOIL REMEDIATION IN HORIZONTAL LASAGNA CELLS  

EPA Science Inventory

An integrated soil remediation technology called Lasagna has been developed that combines electrokinetics with treatment zones for use in low permeability soils where the rates of hydraulic and electrokinetic transport are too low to be useful for remediation of contaminants. The...

112

Field Implementation of Electrokinetic-ISCO Remediation  

NASA Astrophysics Data System (ADS)

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.

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

2010-12-01

113

Ring stains in the presence of electrokinetic interactions  

NASA Astrophysics Data System (ADS)

In this paper, we delineate the consequences of electrokinetic interactions on the “coffee stain” effect, induced by the deposition of particles during drop evaporation. We consider evaporation of an electrolytic drop in contact with a charged substrate and probe the effects of electrical double layer formation at the drop-substrate interface on the dynamics of particles suspended inside the drop. We show that the simultaneous considerations of streaming potential and flow-actuation-mechanism-independent description of the evaporation flux and the depth average velocities result in an enhanced induced radial pressure gradient. As a result, the deposition speed of the particles in the disordered packing regime, occurring at the end of the lifetime of the drop [Marin , Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.107.085502 107, 085502 (2011)], is greatly enhanced. This, in turn, is likely to signify an augmented degree of disordering in the evaporation-induced particle deposition.

Das, Siddhartha; Chakraborty, Suman; Mitra, Sushanta K.

2012-04-01

114

Electrokinetic Hydrogen Generation from Liquid WaterMicrojets  

SciTech Connect

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.

Duffin, Andrew M.; Saykally, Richard J.

2007-05-31

115

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

E-print Network

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

Oakley, Jeremy

116

Effects of Estradiol on Incorporation of New Cells in the Developing Zebra Finch Song System: Potential  

E-print Network

Effects of Estradiol on Incorporation of New Cells in the Developing Zebra Finch Song System masculiniza- tion of the zebra finch song system are unclear; both es- tradiol and sex-specific genes may males than females. Four studies on zebra finches were conducted using bromo- deoxyuridine (Brd

Wade, Juli

117

The effectiveness of incorporating a real-time oculometer system in a commercial flight training program  

NASA Technical Reports Server (NTRS)

The effectiveness on pilot and trainee performance and scanning behavior of incorporating a real time oculometer system in a commerical flight training program was assessed. Trainees received simulator training in pairs requiring the trainees to alternate the order of training within a session. The 'third day phenomenon' of performance decrement was investigated, including the role of order of training on performance.

Jones, D. H.; Coates, G. D.; Kirby, R. H.

1982-01-01

118

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 ...

119

Effects of arsenic incorporation on jarosite dissolution rates and reaction products  

E-print Network

Effects of arsenic incorporation on jarosite dissolution rates and reaction products Matthew R to hematite with time in ultra-pure water, but increasing arsenic concentrations slow this transition. At pH >3.5, arsenic from the dissolution of arsenojarosite adsorbs onto newly formed reaction products

Hu, Qinhong "Max"

120

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

PubMed Central

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

2014-01-01

121

Incorporation of electronically nonadiabatic effects into bimolecular reactive systems. I. Theory  

Microsoft Academic Search

Electronic nonadiabatic interactions are smoothly incorporated into existing exact quantum mechanical methods for treating reactive (or nonreactive) bimolecular systems. A known method for treating reactive systems on a single surface is first given, and then it is shown how to proceed to include electronically nonadiabatic effects. The unexpected result is that the final equations are very similar to those of

Zvi H. Top; Michael Baer

1977-01-01

122

The Effect of Incorporating Cooperative Learning Principles in Pair Programming for Student Teachers  

ERIC Educational Resources Information Center

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…

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

2008-01-01

123

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

ERIC Educational Resources Information Center

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…

Hodge, David R.

2011-01-01

124

Geostatistical Mapping of Mountain Precipitation Incorporating Autosearched Effects of Terrain and Climatic Characteristics  

E-print Network

Geostatistical Mapping of Mountain Precipitation Incorporating Autosearched Effects of Terrain are sensitive to the temporal and spatial distri- bution of precipitation. In this study a geostatistical model mountain precipitation using only precipi- tation gauge data. The ASOADeK model considers both

Texas at San Antonio, University of

125

Simultaneous determination of paracetamol and chlorpheniramine maleate by micellar electrokinetic chromatography  

Microsoft Academic Search

A micellar electrokinetic chromatography (MEKC) method was established for determination of paracetamol (PARA) and chlorpheniramine maleate (CPM) in cold tablets. Separation of both drugs, as well as other seven cold remedy ingredients, was achieved in 25.5 min using a sodium dihydrogenphosphate–sodium tetraborate buffer (10 mM, pH 9.0) containing sodium dodecyl sulfate (SDS) (50 mM) and acetonitrile (26% v\\/v). The effective

Leena Suntornsuk; Ongart Pipitharome; Prapin Wilairat

2003-01-01

126

Determination of piribedil in pharmaceutical formulations by micellar electrokinetic capillary chromatography  

Microsoft Academic Search

A fast and simple micellar electrokinetic capillary chromatographic method was developed for the analysis of piribedil in pharmaceutical formulations. The effects of buffer concentration, buffer pH, sodium dodecyl sulphate (SDS) concentration, organic modifier, applied voltage and injection time were investigated. Optimum results were obtained with a 50 mM borate buffer at pH 8.0 containing 50 mM SDS by using a fused silica capillary

Ceren Yard?mc?; ?ncilay Süslü; Nuran Özalt?n

2004-01-01

127

Incorporation of QCD effects in basic corrections of the electroweak theory  

Microsoft Academic Search

We study the incorporation of QCD effects in the basic electroweak corrections Deltar^, Deltar^W, and Deltar. They include perturbative O(alphaalphas) contributions and tt¯ threshold effects. The latter are studied in the resonance and Green-function approaches, in the framework of dispersion relations that automatically satisfy relevant Ward identities. Refinements in the treatment of the electroweak corrections, in both the modified minimal

Sergio Fanchiotti; Bernd Kniehl; Alberto Sirlin

1993-01-01

128

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

E-print Network

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

Bazant, Martin Z.

129

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

PubMed

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

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

2004-10-01

130

Numerical study of dc-biased ac-electrokinetic flow over symmetrical electrodes  

PubMed Central

This paper presents a numerical study of DC-biased AC-electrokinetic (DC-biased ACEK) flow over a pair of symmetrical electrodes. The flow mechanism is based on a transverse conductivity gradient created through incipient Faradaic reactions occurring at the electrodes when a DC-bias is applied. The DC biased AC electric field acting on this gradient generates a fluid flow in the form of vortexes. To understand more in depth the DC-biased ACEK flow mechanism, a phenomenological model is developed to study the effects of voltage, conductivity ratio, channel width, depth, and aspect ratio on the induced flow characteristics. It was found that flow velocity on the order of mm/s can be produced at higher voltage and conductivity ratio. Such rapid flow velocity is one of the highest reported in microsystems technology using electrokinetics. PMID:22662084

Yang Ng, Wee; Ramos, Antonio; Cheong Lam, Yee; Rodriguez, Isabel

2012-01-01

131

A method of producing electrokinetic power through forward osmosis  

NASA Astrophysics Data System (ADS)

A power generation method for harvesting renewable energy from salinity gradient is proposed. The principle of the proposed method encompasses forward osmosis (FO) and electrokinetic phenomena. With the salinity difference between draw and feed solutions, FO allows spontaneous water flow across a semi-permeable membrane. The flow of water is then directed through a porous medium where the electric power is generated from the electrokinetic streaming potential. With a glass porous medium and a commercial flat sheet FO membrane in a batch mode configuration, our lab scale experimental system has demonstrated the produced electrokinetic voltages of about several hundreds of milli-volts.

Cherng Hon, Kar; Zhao, Cunlu; Yang, Chun; Chay Low, Seow

2012-10-01

132

Development of microtitre plates for electrokinetic assays  

NASA Astrophysics Data System (ADS)

Electrokinetic processes have wide ranging applications in microsystems technology. Their optimum performance at micro and nano dimensions allows their use both as characterization and diagnostic tools and as a means of general particle manipulation. Within analytical studies, measurement of the electrokinesis of biological cells has the sensitivity and selectivity to distinguish subtle differences between cell types and cells undergoing changes and is gaining acceptance as a diagnostic tool in high throughput screening for drug discovery applications. In this work the development and manufacture of an electrokinetic-based microtitre plate is described. The plate is intended to be compatible with automated sample loading and handling systems. Manufacturing of the microtitre plate, which employs indium tin oxide microelectrodes, has been entirely undertaken using excimer and ultra-fast pulsed laser micromachining due to its flexibility in materials processing and accuracy in microstructuring. Laser micromachining has the ability to rapidly realize iterations in device prototype design while also having the capability to be scaled up for large scale manufacture. Device verification is achieved by the measurement of the electrorotation and dielectrophoretic properties of yeast cells while the flexibility of the developed microtitre plate is demonstrated by the selective separation of live yeast from polystyrene microbeads.

Burt, J. P. H.; Goater, A. D.; Menachery, A.; Pethig, R.; Rizvi, N. H.

2007-02-01

133

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

USGS Publications Warehouse

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.

Thorn, Kevin A.; Cox, Larry G.

2012-01-01

134

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

Microsoft Academic Search

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

Graham H. Smith; Dalma Novak; Zaheer Ahmed

1997-01-01

135

The effect of incorporation of steatite wastes on the mechanical properties of cementitious composites  

Microsoft Academic Search

The recycling of mineral wastes is considered today an activity of utmost importance, contributing in the diversification\\u000a of products, reduction of final costs, besides promoting alternative raw materials for some industrial sectors. This work\\u000a focuses on the incorporation of steatite wastes in cementitious composites. A full design of experiment was carried out in\\u000a order to investigate the effect of the

K. Strecker; T. H. Panzera; A. L. R. Sabariz; J. S. Miranda

2010-01-01

136

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...

137

SITE TECHNOLOGY CAPSULE; IN SITU ELECTROKINETIC EXTRACTION SYSTEM  

EPA Science Inventory

As a part of the Superfund Innovative Technology Evaluation (SITE) Program, the U.S. Environmental Protection Agency evaluated the In-Situ Electrokinetic Extraction (ISEE) system at Sandia National Laboratories, Albuquerque, New Mexico. The SITE demonstration results show ...

138

Utilization of sweet kalina lupin seed by the weaned piglet Effect of the incorporation level and the physical form  

E-print Network

Utilization of sweet kalina lupin seed by the weaned piglet Effect of the incorporation level, containing 0, 3, 6 and 9 p. 100 lupin and offered as pellets. In a second trial concerning 400 crossbred piglets we tested the effect of incorporation of 10 p. 100 lupin in diets offered either as flour

Paris-Sud XI, Université de

139

Preliminary results of a UV-B effect incorporated GOSSYM model  

NASA Astrophysics Data System (ADS)

Field experiments and laboratory tests have shown multiple effects of enhanced ultraviolet-B (UV-B) radiation on cotton growth, development, and yield. Adverse effects include development of chlorotic and necrotic patches on leaves, reductions in total leaf area, plant height, photosynthesis, and yield. However, little work has been carried out to incorporate these experimental results into a simulation model and to estimate the effects of UV-B radiation under field conditions with varied environments and management practices. This study incorporates experimental results of UV-B effects on cotton crop into a cotton simulation model, GOSSYM, which is being used widely in various applications. In this work, first modules were modified to incorporate the effects of UV-B radiation on canopy photosynthesis, leaf area expansion, and stem and branch elongation. Then, the modified model was used to test the validity of model assumptions and algorithms on independent experimental data sets. Finally, preliminary studies were performed to simulate the effects of UV-B radiation in the field conditions at Stoneville, Mississippi using 30-year (1964-1993) climate data. Simulation results agreed well with experimental measurements, proving the validation of the model. Our results suggest that cotton lint yield declined with increased UV-B radiation. The reductions were 20% when UV-B irradiance was 12 kJ m -2 under irrigated conditions. Similar reductions in yield were predicted at lower UV-B radiation (11 kJ m -2) under rain-fed conditions. The modified model will be useful to simulate the impacts of UV-B radiation on cotton growth and yield under current and future climatic conditions and to suggest management options to mitigate the adverse effects.

Wang, Xinli; Gao, Wei; Reddy, K. Raja; Slusser, James; Xu, Min

2006-08-01

140

Electrokinetics of pH-regulated zwitterionic polyelectrolyte nanoparticles  

NASA Astrophysics Data System (ADS)

The electrokinetic behavior of pH-regulated, zwitterionic polyelectrolyte (PE) nanoparticles (NPs) in a general electrolyte solution containing multiple ionic species is investigated for the first time. The NPs considered are capable of simulating entities such as proteins, biomolecules, and synthetic polymers. The applicability of the model proposed is verified by the experimental data of succinoglycan nanoparticles available in the literature. We show that, in addition to their effective charge density, counterion condensation, double-layer polarization, and electro-osmotic flow of unbalanced counterions inside the double layer all significantly affect the electrophoretic behaviors of NPs. Our model successfully predicts many interesting electrophoretic behaviors, which qualitatively agree with experimental observations available in the literature. In contrast, because the effects of double-layer polarization and charge regulation are neglected, the existing theoretical models fail to explain the experimental results. The results gathered provide necessary information for the interpretation of relevant electrophoresis data in practice, and for nanofluidic applications such as biomimetic ion channels and nanopore-based sensing of single biomolecules.The electrokinetic behavior of pH-regulated, zwitterionic polyelectrolyte (PE) nanoparticles (NPs) in a general electrolyte solution containing multiple ionic species is investigated for the first time. The NPs considered are capable of simulating entities such as proteins, biomolecules, and synthetic polymers. The applicability of the model proposed is verified by the experimental data of succinoglycan nanoparticles available in the literature. We show that, in addition to their effective charge density, counterion condensation, double-layer polarization, and electro-osmotic flow of unbalanced counterions inside the double layer all significantly affect the electrophoretic behaviors of NPs. Our model successfully predicts many interesting electrophoretic behaviors, which qualitatively agree with experimental observations available in the literature. In contrast, because the effects of double-layer polarization and charge regulation are neglected, the existing theoretical models fail to explain the experimental results. The results gathered provide necessary information for the interpretation of relevant electrophoresis data in practice, and for nanofluidic applications such as biomimetic ion channels and nanopore-based sensing of single biomolecules. Electronic supplementary information (ESI) available: Detailed description of the effects of counterion condensation (CC) and double-layer polarization (DLP), the illustrated transformation of the perturbed flow and pressure fields in sub-problem two due to a CC effect, and the influence of the softness parameter of a PE NP on the scaled forces acting on it for the case of Fig. 10. See DOI: 10.1039/c2nr32277c

Yeh, Li-Hsien; Tai, Yi-Hsuan; Wang, Nan; Hsu, Jyh-Ping; Qian, Shizhi

2012-11-01

141

Enhancement of anti-inflammatory effects of biphenylylacetic acid by its incorporation into lipid microspheres.  

PubMed

Using lipid microspheres (LM), average diameter 0.2 micron, and containing methyl and ethyl esters of biphenylylacetic acid (BPAA) in the carrageenan paw oedema tests in rats, it was found that their anti-inflammatory activities were enhanced 3 to 8 times over that of free BPAA. By electron microscopy, LM were seen to be taken up into the endothelial cells of the blood vessels and macrophages at the inflamed sites. In a study using dogs, after an intravenous injection of BPAA-methyl ester incorporated into LM (lipo-BPAA-Me), lipo-BPAA-Me rapidly disappeared from the blood and the BPAA serum level was gradually elevated. These results, together with previous findings, suggest that part of lipo-BPAA-Me was immediately transferred to the inflamed site and taken up by prostaglandin (PG)-producing cells as macrophages. It is considered that the anti-inflammatory effects of BPAA are enhanced by incorporating it into LM. PMID:2870154

Shoji, Y; Mizushima, Y; Yanagawa, A; Shiba, T; Takei, H; Fujii, M; Amino, M

1986-02-01

142

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

SciTech Connect

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.

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

143

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

E-print Network

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 be captured, rather than cause flooding, overload to sewer sys

Rhode Island, University of

144

Inhibitory Effect of Solar Radiation on Thymidine and Leucine Incorporation by Freshwater and Marine Bacterioplankton  

PubMed Central

We studied the effect of solar radiation on the incorporation of [(sup3)H]thymidine ([(sup3)H]TdR) and [(sup14)C]leucine ([(sup14)C]Leu) by bacterioplankton in a high mountain lake and the northern Adriatic Sea. After short-term exposure (3 to 4 h) of natural bacterial assemblages to sunlight just beneath the surface, the rates of incorporation of [(sup3)H]TdR and [(sup14)C]Leu were reduced at both sites by up to (symbl)70% compared to those for the dark control. Within the solar UV radiation (290 to 400 nm), the inhibition was caused exclusively by UV-A radiation (320 to 400 nm). However, photosynthetically active radiation (PAR) (400 to 700 nm) contributed almost equally to this effect. Experiments with samples from the high mountain lake showed that at a depth of 2.5 m, the inhibition was caused almost exclusively by UV-A radiation. At a depth of 8.5 m, where chlorophyll a concentrations were higher than those in the upper water column, the rates of incorporation of [(sup3)H]TdR were higher in those samples exposed to full sunlight or to UV-A plus PAR than in the dark control. In laboratory experiments with artificial UV light, the incorporation of [(sup3)H]TdR and [(sup14)C]Leu by mixed bacterial lake cultures was also inhibited mainly by UV-A. In contrast, in the presence of the green alga Chlamydomonas geitleri at a chlorophyll a concentration of 2.5 (mu)g liter(sup-1), inhibition by UV radiation was significantly reduced. These results suggest that there may be complex interactions among UV radiation, heterotrophic bacteria, and phytoplankton and their release of extracellular organic carbon. Our findings indicate that the wavelengths which caused the strongest inhibition of TdR and Leu incorporation by bacterioplankton in the water column were in the UV-A range. However, it may be premature to extrapolate this effect to estimates of bacterial production before more precise information on how solar radiation affects the transport of TdR and Leu into the cell is obtained. PMID:16535724

Sommaruga, R.; Obernosterer, I.; Herndl, G. J.; Psenner, R.

1997-01-01

145

Method and apparatus for electrokinetic transport  

NASA Technical Reports Server (NTRS)

Controlled electrokinetic transport of constituents of liquid media can be achieved by connecting at least two volumes containing liquid media with at least one dielectric medium with opposing dielectric surfaces in direct contact with said liquid media, and establishing at least one conduit across said dielectric medium, with a conduit inner surface surrounding a conduit volume and at least a first opening and a second opening opposite to the first opening. The conduit is arranged to connect two volumes containing liquid media and includes a set of at least three electrodes positioned in proximity of the inner conduit surface. A power supply is arranged to deliver energy to the electrodes such that time-varying potentials inside the conduit volume are established, where the superposition of said potentials represents at least one controllable traveling potential well that can travel between the opposing conduit openings.

James, Patrick Ismail (Inventor); Stejic, George (Inventor)

2012-01-01

146

Electrokinetic coupling in hydraulic fracture propagation  

NASA Astrophysics Data System (ADS)

Electrokinetic coupling is the most popular mechanism proposed to explain observed electromagnetic signals associated with the hydraulic fracturing of rocks. Measurements in both controlled laboratory and in situ conditions show clear evidence of the phenomenon. However there have been no reports on the description of the source mechanism, its relationship to a propagating crack, nor the electromagnetic field distribution due to such a source advancing through an electrically conductive medium. In this work it is shown that a surface electric current density arising on the walls of a fluid driven propagating crack can explain the measurements of electric streaming potential recorded during hydraulic fracturing experiments. The properties of the streaming current source are studied at the microscopic scale in light of the electrokinetic coupling expected at the outermost grains of the crack's surface. Expressions are derived for the average macroscopic transport equations describing the coupled fluid, and electrical current flow, at the interface between a fluid continuum and a homogeneous porous medium, where a Darcy flow regime (porous medium) competes with a rather Poiseuille type (fracture channels). The properties of the electrokinetic boundary sources are analyzed in light of the average electrical current density arising on the interface, as the fluid electrolyte flows in both the porous media and the adjacent fluid continuum. It is found that two coupling coefficients are required to describe the streaming current density. Indeed the flow is driven by both, a tangential pressure gradient, as well as by forward momentum transfer across the permeable boundary. The coupling coefficients are obtained from the spatial average of the tangential stress exerted on the pore surfaces, and they are found to be position dependent, as the tangential stress transitions from that on the porous conduits, to that on the surface of the outer most grains. Furthermore each coefficient gives rise to both a volumetric current density, due to the flow along the pore conduits, as well as a surface current density, due to the flow along the outer most surface. The latter contribution is found to dominate, as the tangential stress scales with the macroscopic characteristic length of the system. From a macroscopic stand point a source space-time function is established for the average current density prescribed by the pressure profile expected at the walls of a crack, which propagates under mobile equilibrium, in the context of linear elasticity theory. Expressions for the electromagnetic fields due to such a source are derived for a crack propagating with a constant velocity, in a homogeneous isotropic conducting medium. It is found that the spatial and temporal behavior of the fields reasonably agree with measurements performed under controlled laboratory experiments. In situ measurements are only studied qualitatively. Nevertheless, despite the obvious fact that a homogeneous whole-space medium does not appropriately describe a realistic earth model, the magnitude of the fields and the temporal behavior of the signals can be well reproduced using typical parameters of a hydraulic fracturing procedure. Electrokinetic coupling has also been proposed in the context of earthquake precursory signals, due to dilatant crack growth at depth. Several ideas have been discussed in the literature in order to justify experimental measurements of electromagnetic field which presumably appear before the onset of an earthquake. The source mechanism described in the present report, occurring at depth ranges of earthquake slip zones, yields electromagnetic signal levels which are 3 orders of magnitude smaller than the noise floor of currently available commercial instrumentation. This suggests that observing this type of phenomenon as an earthquake precursor would then be very challenging.

Cuevas, Nestor Herman

2009-12-01

147

Implementation of Electrokinetic-ISCO Remediation  

NASA Astrophysics Data System (ADS)

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.

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

2011-12-01

148

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

E-print Network

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

Park, Namkyoo

149

Effects of incorporation of Na in spray pyrolysed CuInS 2 thin films  

NASA Astrophysics Data System (ADS)

We investigated the effect of intentional incorporation of sodium on the structural, optical and electrical properties of Cu-poor CuInS 2 thin films. Samples having a low concentration of Na exhibit better crystallinity and a remarkable increase in electrical conductivity as well as photosensitivity, compared to the undoped films. Doping of Na results in an increase of the oxygen concentration, as judged by X-ray Photoelectron Spectroscopy. However, a larger concentration of sodium (greater than 0.3%) is found to deteriorate the film properties, but the sample is still better than the undoped sample.

Theresa John, Teny; Sebastian, Tina; Sudha Kartha, C.; Vijayakumar, K. P.; Abe, T.; Kashiwaba, Y.

2007-01-01

150

Dehalorespiration model that incorporates the self-inhibition and biomass inactivation effects of high tetrachloroethene concentrations.  

PubMed

In the vicinity of dense nonaqueous phase liquid (DNAPL) contaminant source zones, aqueous concentrations of tetrachloroethene (PCE) in groundwater may approach saturation levels. In this study, the ability of two PCE-respiring strains (Desulfuromonas michiganensis and Desulfitobacterium strain PCE1) to dechlorinate high concentrations of PCE was experimentally evaluated and depended on the initial biomass concentration. This suggests high PCE concentrations permanently inactivated a fraction of biomass, which, if sufficiently large, prevented dechlorination from proceeding. The toxic effects of PCE were incorporated into a model of dehalorespirer growth by adapting the transformation capacity concept previously applied to describe biomass inactivation by products of cometabolic TCE oxidation. The inactivation growth model was coupled to the Andrews substrate utilization model, which accounts for the self-inhibitory effects of PCE on dechlorination rates, and fit to the experimental data. The importance of incorporating biomass inactivation and self-inhibition effects when modeling reductive dechlorination of high PCE concentrations was demonstrated by comparing the goodness-of-fit of the Andrews biomass inactivation and three alternate models that do capture these factors. The new dehalorespiration model should improve our ability to predict contaminant removal in DNAPL source zones and determine the inoculum size needed to successfully implement bioaugmentation of DNAPL source zones. PMID:21182287

Huang, Deyang; Becker, Jennifer G

2011-02-01

151

Determination of itraconazole and hydroxyitraconazole in human serum and plasma by micellar electrokinetic chromatography  

Microsoft Academic Search

The electrokinetic separation of the hydrophobic antimycotic drug itraconazole (ITC) and its major metabolite, hydroxyitraconazole (HITC), by a binary aqueous–organic solvent medium containing sodium dodecylsulfate, by microemulsion electrokinetic chromatography (MEEKC) and by micellar electrokinetic chromatography (MEKC) was studied. The results suggest that the first approach is difficult to apply and that there is no substantial difference between separations performed using

Michael C Breadmore; Andrea Procházková; Regula Theurillat; Wolfgang Thormann

2003-01-01

152

Journal of Chromatography A, 807 (1998) 111119 Microemulsion electrokinetic chromatography of fatty acids as  

E-print Network

Journal of Chromatography A, 807 (1998) 111­119 Microemulsion electrokinetic chromatography by microemulsion electrokinetic chromatography. Separations were done by using an untreated fused-silica capillary/w) and n-butanol (6.55%, w/w), pH 10.2. Separation by microemulsion electrokinetic chromatography

Miksik, Ivan

1998-01-01

153

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

Microsoft Academic Search

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

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

1995-01-01

154

Electrokinetic demonstration at the unlined chromic acid pit  

SciTech Connect

Heavy-metal contaminated soils are a common problem at Department of Energy (DOE)-operated sites and privately owned facilities throughout the nation. One emerging technology which can remove heavy metals from soil in situ is electrokinetics. To conduct electrokinetic (EK) remediation, electrodes are implanted into the ground, and a direct current is imposed between the electrodes. Metal ions dissolved in the soil pore water migrate towards an electrode where they can be removed. The electrokinetic program at Sandia National Laboratories (SNL) has been focusing on electrokinetic remediation for unsaturated soils. A patent was awarded for an electrokinetic electrode system designed at SNL for applications to unsaturated soils. Current research described in this report details an electrokinetic remediation field demonstration of a chromium plume that resides in unsaturated soil beneath the SNL Chemical Waste Landfill (CWL). This report describes the processes, site investigation, operation and monitoring equipment, testing procedures, and extraction results of the electrokinetic demonstration. This demonstration successfully removed chromium contamination in the form of chromium(VI) from unsaturated soil at the field scale. After 2700 hours of operation, 600 grams of Cr(VI) was extracted from the soil beneath the SNL CWL in a series of thirteen tests. The contaminant was removed from soil which has moisture contents ranging from 2 to 12 weight percent. This demonstration was the first EK field trial to successfully remove contaminant ions from and soil at the field scale. Although the new patented electrode system was successful in removing an anionic contaminant (i.e., chromate) from unsaturated sandy soil, the electrode system was a prototype and has not been specifically engineered for commercialization. A redesign of the electrode system as indicated by the results of this research is suggested for future EK field trials.

Lindgren, E.R.; Hankins, M.G. [Sandia National Labs., Albuquerque, NM (United States); Mattson, E.D. [Salt-Unsat, Inc., Albuquerque, NM (United States); Duda, P.M. [Ktech Corp., Albuquerque, NM (United States)

1998-01-01

155

Pneumatic v electrokinetic lithotripsy in treatment of ureteral stones.  

PubMed

Recently, a new device (Combilith) for electrokinetic lithotripsy (EKL) has become available which is very similar to the well-known device for pneumatic (ballistic) lithotripsy (Swiss Lithoclast). The Lithoclast uses air pressure to push a projectile within the handpiece against the end of a metal probe, which is thereby accelerated and thrown like a jackhammer against the stone. In principle, the same stroking movement of a small metal probe is provided by EKL; the difference is that instead of a projectile, a magnetic core within the handpiece is accelerated by the electromagnetic principle. This paper compares the clinical efficacy and the features of the two devices. Testing the devices on a stone model, taking into account stone propulsion, the systems turned out to equally effective regarding stone disintegration. However, stone displacement was more pronounced with the Lithoclast applied on easily breaking stones. In a second experiment, an optoelectronic movement-measuring apparatus (Zimmer camera) was employed to measure the range and velocity of the movement of the probe tip without any contact. The linear acceleration velocity ranged from 5 to a maximum of 12.5 m/sec with both systems, but the maximum height of the stroke was 2.5 mm with the Lithoclast and 1 mm with EKL. After the initial break-up of soft stones, further impact of the probe tip against the stone resulted merely in propulsion; thus, the greater probe stroke height is the cause of the stone displacement. In a clinical trial, 22 ureteral stones were treated with the Lithoclast and 35 with the EKL. The two devices were equally effective in terms of stone disintegration and safety margin. Fixation using a Dormia basket was necessary in 12 cases (8 Lithoclast, 4 EKL). Although a difference in probe stroke height was noted when comparing pneumatic and electrokinetic lithotripsy, there were no clinically significant differences in the efficacy of stone fragmentation or stone-free rates. At the current time, EKL is less costly. PMID:9658292

Vorreuther, R; Klotz, T; Heidenreich, A; Nayal, W; Engelmann, U

1998-06-01

156

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

NASA Astrophysics Data System (ADS)

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.

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

2012-11-01

157

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

PubMed

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. PMID:23060604

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

2012-11-01

158

Elementary framework for cold field emission: Incorporation of quantum-confinement effects  

SciTech Connect

Although the Fowler-Nordheim (FN) equation serves as the foundation of cold field emission theory, it may not be suitable for predicting the emitted current density (ECD) from emitters with a quantum-confined electron supply. This work presents an analytical framework for treating cold field emission from metals that includes the effects of a quantum-confined electron supply. Within the framework, quantum confinement in emitters is classified into transverse and normal quantum confinement based on the orientation of the confinement relative to the emission direction. The framework is used to generate equations predicting the ECD from rectangular and cylindrical emitter geometries comprised of electron supplies of reduced dimensionality. Transverse quantum confinement of the electron supply leads to a reduction in the total ECD as transverse emitter dimensions decrease and normal quantum confinement results in an oscillatory ECD as a function of the normal quantum well width. Incorporating a geometry-dependent field enhancement factor into the model reveals an optimal transverse well width for which quantum confinement of the electron supply and field enhancement equally affect the ECD and a maximum total ECD for the emitter geometry at a given applied field is obtained. As a result, the FN equation over-predicts the ECD from emitters with transverse dimensions under approximately 5?nm, and in those cases, geometry-specific ECD equations incorporating quantum-confinement effects should be employed instead.

Patterson, A. A., E-mail: apatters@mit.edu; Akinwande, A. I. [Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Microsystems Technology Laboratories, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

2013-12-21

159

Separation of hydrophobic polymer additives by microemulsion electrokinetic chromatography.  

PubMed

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

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

2001-07-13

160

Characterization of a silver-incorporated calcium phosphate film by RBS and its antimicrobial effects  

NASA Astrophysics Data System (ADS)

A thin calcium phosphate film was synthesized on both commercially pure Ti and Si wafers by electron beam evaporation of hydroxyapatite as an evaporant with simultaneous Ar ion beam bombardments. Silver was introduced into an ion-beam-assisted deposition of a calcium phosphate thin film for antimicrobial effect. The amount of incorporated silver ions was controlled by immersing calcium-phosphate-coated samples in different AgNO3 concentrations, and Rutherford backscattering spectrometry (RBS) was employed to measure the amounts of substituted silver. The higher concentration of silver in the calcium phosphate film was more effective in reducing the bacteria of Escherichia coli ATCC 8739 and Streptococcus mutans OMZ 65 on contact with respect to controls.

Han, I.-H.; Lee, I.-S.; Song, J.-H.; Lee, M.-H.; Park, J.-C.; Lee, G.-H.; Sun, X.-D.; Chung, S.-M.

2007-09-01

161

Determining the Effectiveness of Incorporating Geographic Information Into Vehicle Performance Algorithms  

SciTech Connect

This thesis presents a research study using one year of driving data obtained from plug-in hybrid electric vehicles (PHEV) located in Sacramento and San Francisco, California to determine the effectiveness of incorporating geographic information into vehicle performance algorithms. Sacramento and San Francisco were chosen because of the availability of high resolution (1/9 arc second) digital elevation data. First, I present a method for obtaining instantaneous road slope, given a latitude and longitude, and introduce its use into common driving intensity algorithms. I show that for trips characterized by >40m of net elevation change (from key on to key off), the use of instantaneous road slope significantly changes the results of driving intensity calculations. For trips exhibiting elevation loss, algorithms ignoring road slope overestimated driving intensity by as much as 211 Wh/mile, while for trips exhibiting elevation gain these algorithms underestimated driving intensity by as much as 333 Wh/mile. Second, I describe and test an algorithm that incorporates vehicle route type into computations of city and highway fuel economy. Route type was determined by intersecting trip GPS points with ESRI StreetMap road types and assigning each trip as either city or highway route type according to whichever road type comprised the largest distance traveled. The fuel economy results produced by the geographic classification were compared to the fuel economy results produced by algorithms that assign route type based on average speed or driving style. Most results were within 1 mile per gallon ({approx}3%) of one another; the largest difference was 1.4 miles per gallon for charge depleting highway trips. The methods for acquiring and using geographic data introduced in this thesis will enable other vehicle technology researchers to incorporate geographic data into their research problems.

Sera White

2012-04-01

162

Manifestation of second-order nonlinear optical effects in KTP and RTP nanocrystallites incorporated into polymer matrices  

Microsoft Academic Search

Strong second-order optical effects in KTiOPO4 (KTP) nanocrystallites incorporated into polymethylmethacrylate (PMMA) matrices have been found. The maximally achieved value of the effective second-order susceptibility was equal to about 2.2pm\\/V at laser wavelength 1320nm and at liquid helium temperature (LHeT). It corresponds to concentration of the nanocrystallites of about 5.6% in weighting units. Incorporation of Rb ions and finally conversion

O. Faugeroux; A. Majchrowski; J. Rutkowski; S. Klosowicz; M. Caussanel; S. Tkaczyk

2008-01-01

163

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

NASA Astrophysics Data System (ADS)

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.

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

2014-07-01

164

On incorporating post-Newtonian effects in N-body dynamics  

E-print Network

The increasing role of general relativity in the dynamics of stellar systems with central massive black holes and in the evolution of hierarchical triple systems inspires a close examination of how post-Newtonian effects are incorporated into N-body dynamics. The majority of approaches incorporate relativity by adding to the Newtonian N-body equations the standard two-body post-Newtonian terms for a given star around the black hole or for the close binary in a triple system. We argue that, for calculating the evolution of such systems over timescales comparable to the relativistic pericenter advance timescale, it is essential to include "cross terms" in the equations of motion. These are post-Newtonian terms that represent a coupling between the potential of the central black hole and the potential due to other stars in the system. For hierarchical triple systems, these are couplings between the potential of the inner binary and that of the distant third body. Over pericenter precession timescales, the effects of such terms can actually be "boosted" to amplitudes of Newtonian order. We write down the post-Newtonian N-body equations of motion including a central black hole in a truncated form that includes all the relevant cross terms, in a format ready to use for numerical implementation. We do the same for hierarchical triple systems, and illustrate explicitly the effects of cross terms on the orbit-averaged equations of evolution for the orbit elements of the inner binary for the special case where the third body is on a circular orbit. We also describe the inspiration for this investigation: the motion of a test body about a central body with a Newtonian quadrupole moment, including the relativistic pericenter advance, whose correct solution for the conserved total Newtonian energy requires including PN cross terms between the mass monopole and quadrupole potentials.

Clifford M. Will

2014-04-10

165

Microchip separations of neutral species via micellar electrokinetic capillary chromatography  

SciTech Connect

Micellar electrokinetic capillary chromatography (MECC) of three neutral coumarin dyes was performed on glass microchips. Manifolds of channels for analyte injection and separation were machined into one surface of the glass substrates using standard photolithographic, etching, and deposition techniques. Cover plates were then directly bonded over these channels to form capillary networks, with fluid flow in these networks controlled by varying the applied high-voltage potentials at the outlets. The separation capillary was 16.5 cm long for a serpentine channel chip and 1.3 cm long for a straight channel chip. Detection of analyte zones was accomplished by laser-induced fluorescence using the UV lines (nearly 350 nm) of an argon ion laser. At low applied electric field strengths, MECC analyses with on-chip injections gave high reproducibilities in peak areas and migration times (<1% for two of the three coumarins) and near constant separation efficiencies throughout the analysis. At high fields (>400 V/cm), analysis times were shorter, but separation efficiency decreased at later migration times. These peaks showed significant broadening, consistent with mass transfer effects. 14 refs., 6 figs., 2 tabs.

Moore, A.W. Jr.; Jacobson, S.C.; Ramsey, J.M. [Oak Ridge National Lab., TN (United States)

1995-11-15

166

ELECTROKINETIC MEMBRANE PROCESSES IN RELATION TO PROPERTIES OF EXCITABLE TISSUES  

PubMed Central

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

Teorell, Torsten

1959-01-01

167

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

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

168

Method for eliminating gas blocking in electrokinetic pumping systems  

DOEpatents

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.

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

2001-09-11

169

Transport of radioactive ions in soil by electrokinetics  

SciTech Connect

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.

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

1994-10-01

170

Effects of Toxic Substances on Natural Bacterial Assemblages Determined by Means of [3H]Thymidine Incorporation  

PubMed Central

The effects of 3,5-dichlorophenol, 2,4-dinitrophenol, and potassium dichromate on natural bacterial assemblages were examined by means of [3H]thymidine incorporation into trichloroacetic acid-insoluble material. Results from a large number of coastal marine and freshwater samples suggest the following. (i) The effects of the three toxicants included reductions in the bacterial cell number as well as changes in rates of [3H]thymidine incorporation and in [3H]thymidine incorporation per cell. The concentrations that inhibited [3H]thymidine incorporation by 50% ranged from 3 to 11 mg liter?1 for 3,5-dichlorophenol, 6 to 10 mg liter?1 for 2,4-dinitrophenol, and 21 to 123 mg liter?1 for potassium dichromate, with a tendency to higher values in bacterial assemblages from more eutrophic environments. (ii) The effects of 3,5-dichlorophenol and potassium dichromate determined by [3H]leucine incorporation into bacterial protein were similar or larger than those obtained from [3H]thymidine incorporation. (iii) Two to four hours of exposure to the toxicants was necessary before stable maximum effects were found in [3H]thymidine incorporation. (iv) Storage of natural environmental samples should be avoided, since tests with water stored for 1 to 3 days sometimes produced results different from results obtained from in situ tests. (v) The effects of 3,5-dichlorophenol, 2,4-dinitrophenol, and potassium dichromate on natural bacterial assemblages were relatively constant during periods with different growth rates in the assemblages, during various periods of the year, and between samples from freshwater and marine localities. With some precautions, [3H]thymidine incorporation can be used as a quick and sensitive method for determining the effects of toxicants on aquatic bacterial assemblages from natural environmental samples. PMID:16348108

Riemann, Bo; Lindgaard-Jørgensen, Palle

1990-01-01

171

Electrolysis-reducing electrodes for electrokinetic devices.  

PubMed

Direct current electrokinetic systems generally require Faradaic reactions to occur at a pair of electrodes to maintain an electric field in an electrolyte connecting them. The vast majority of such systems, e.g. electrophoretic separations (capillary electrophoresis) or electroosmotic pumps (EOPs), employ electrolysis of the solvent in these reactions. In many cases, the electrolytic products, such as H+ and OH? in the case of water, can negatively influence the chemical or biological species being transported or separated, and gaseous products such as O? and H? can break the electrochemical circuit in microfluidic devices. This article presents an EOP that employs the oxidation/reduction of the conjugated polymer poly(3,4-ethylenedioxythiophene), rather than electrolysis of a solvent, to drive flow in a capillary. Devices made with poly(3,4-ethylenedioxythiophene) electrodes are compared with devices made with Pt electrodes in terms of flow and local pH change at the electrodes. Furthermore, we demonstrate that flow is driven for applied potentials under 2?V, and the electrodes are stable for potentials of at least 100?V. Electrochemically active electrodes like those presented here minimize the disadvantage of integrated EOP in, e.g. lab-on-a-chip applications, and may open new possibilities, especially for battery-powered disposable point-of-care devices. PMID:21425174

Erlandsson, Per G; Robinson, Nathaniel D

2011-03-01

172

Ca2+-induced effect on mechanical properties of sulfatide-incorporated vesicles.  

PubMed

The Ca(2+)-induced effect on the nanomechanical properties of vesicles prepared at a different ratio of dipalmitoylphosphatidylcholine (DPPC)/sulfatide was studied using atomic force microscope (AFM) on a mica surface. Vesicles were prepared by extrusion and adsorbed on the mica surface. The forces, measured between an AFM tip and the vesicle, showed that the breakthrough of the tip into the vesicles occurred two times. Force data prior to the first breakthrough were fitted well with the Hertzian model to estimate Young's modulus and bending modulus of the vesicles. Sulfatide incorporation led to a decrease of around 90% in Young's modulus and bending modulus of the vesicles due to the hydration of the headgroups, while the addition of Ca(2+) induced dehydration to recover the properties. The change of the physical properties seems to be attributed to the headgroup packing order of the vesicles, which is determined by the interference with the hydration shell. PMID:21088830

Park, Jin-Won

2010-12-01

173

Effects of n-3 PUFAs on breast cancer cells through their incorporation in plasma membrane  

PubMed Central

Background PUFAs are important molecules for membrane order and function; they can modify inflammation-inducible cytokines production, eicosanoid production, plasma triacylglycerol synthesis and gene expression. Recent studies suggest that n-3 PUFAs can be cancer chemopreventive, chemosuppressive and auxiliary agents for cancer therapy. N-3 PUFAs could alter cancer growth influencing cell replication, cell cycle, and cell death. The question that remains to be answered is how n-3 PUFAs can affect so many physiological processes. We hypothesize that n-3 PUFAs alter membrane stability, modifying cellular signalling in breast cancer cells. Methods Two lines of human breast cancer cells characterized by different expression of ER and EGFR receptors were treated with AA, EPA or DHA. We have used the MTT viability test and expression of apoptotic markers to evaluate the effect of PUFAs on cancer growth. Phospholipids were analysed by HPLC/GC, to assess n-3 incorporation into the cell membrane. Results We have observed that EPA and DHA induce cell apoptosis, a reduction of cell viability and the expression of Bcl2 and procaspase-8. Moreover, DHA slightly reduces the concentration of EGFR but EPA has no effect. Both EPA and DHA reduce the activation of EGFR. N-3 fatty acids are partially metabolized in both cell lines; AA is integrated without being further metabolized. We have analysed the fatty acid pattern in membrane phospholipids where they are incorporated with different degrees of specificity. N-3 PUFAs influence the n-6 content and vice versa. Conclusions Our results indicate that n-3 PUFA feeding might induce modifications of breast cancer membrane structure that increases the degree of fatty acid unsaturation. This paper underlines the importance of nutritional factors on health maintenance and on disease prevention. PMID:21569413

2011-01-01

174

Effect on chlorine incorporation as Mg is alloyed into ZnSe  

NASA Astrophysics Data System (ADS)

We have investigated chlorine incorporation in ZnSe and ZnxMg1-xSe through both modeling and experiment. Solubility issues, native defects and chlorine-impurity-related defects have been studied using the ab initio full potential linear muffin-tin-orbital method. Our calculations indicate that the addition of Mg reduces the formation energy for chlorine on the Se site, thereby predicting increased solubility. Subsequent chlorine doping experiments in ZnxMg1-xSe using molecular beam epitaxy indicated significantly higher chlorine incorporation in the presence of magnesium, directly supporting the prediction of the calculations. Calculations support the strong tendency for the formation of a defect complex between a chlorine impurity at the Se site and a vacancy at the neighboring Zn site for heavy n-type doping. The formation of this defect serves to compensate, i.e., negate, the chlorine as an n-type dopant. Experimental observations indicated that significant compensation occurs for heavy Cl doping. There are competing mechanisms that contribute to the effect of magnesium on chlorine when used as an n-type dopant in ZnSe. First, the formation energies for chlorine substituting for selenium decrease in the presence of magnesium. Second, the formation energies of the ClSe-VZn complex also decrease. Finally, the band gap increases in the presence of magnesium, decreasing the net electron concentration at room temperature. Thus, the net effect of adding magnesium is to decrease the maximum achievable carrier concentration through the use of chlorine as an n-type dopant.

Yang, Yaxiang; Vanmil, Brenda; Muratov, Leonid; Cooper, Bernard R.; Myers, Thomas H.; Wills, John M.

2002-10-01

175

Quantitative determination of decitabine incorporation into DNA and its effect on mutation rates in human cancer cells.  

PubMed

Decitabine (5-aza-2'-deoxycytidine) is a DNA methyltransferase inhibitor and an archetypal epigenetic drug for the therapy of myeloid leukemias. The mode of action of decitabine strictly depends on the incorporation of the drug into DNA. However, DNA incorporation and ensuing genotoxic effects of decitabine have not yet been investigated in human cancer cell lines or in models related to the approved indication of the drug. Here we describe a robust assay for the quantitative determination of decitabine incorporation rates into DNA from human cancer cells. Using a panel of human myeloid leukemia cell lines we show appreciable amounts of decitabine incorporation that closely correlated with cellular drug uptake. Decitabine incorporation was also detectable in primary cells from myeloid leukemia patients, indicating that the assay is suitable for biomarker analyses to predict drug responses in patients. Finally, we also used next-generation sequencing to comprehensively analyze the effects of decitabine incorporation on the DNA sequence level. Interestingly, this approach failed to reveal significant changes in the rates of point mutations and genome rearrangements in myeloid leukemia cell lines. These results indicate that standard rates of decitabine incorporation are not genotoxic in myeloid leukemia cells. PMID:25159616

Öz, Simin; Raddatz, Günter; Rius, Maria; Blagitko-Dorfs, Nadja; Lübbert, Michael; Maercker, Christian; Lyko, Frank

2014-10-29

176

Injection by hydrostatic pressure in conjunction with electrokinetic force on a microfluidic chip.  

PubMed

A simple method was developed for injecting a sample on a cross-form microfluidic chip by means of hydrostatic pressure combined with electrokinetic forces. The hydrostatic pressure was generated simply by adjusting the liquid level in different reservoirs without any additional driven equipment such as a pump. Two dispensing strategies using a floating injection and a gated injection, coupled with hydrostatic pressure loading, were tested. The fluorescence observation verified the feasibility of hydrostatic pressure loading in the separation of a mixture of fluorescein sodium salt and fluorescein isothiocyanate. This method was proved to be effective in leading cells to a separation channel for single cell analysis. PMID:15213989

Gai, Hongwei; Yu, Linfen; Dai, Zhongpeng; Ma, Yinfa; Lin, Bingcheng

2004-06-01

177

Fast Myoglobin Detection Using Nanofluidic Electrokinetic Trapping Technique  

NASA Astrophysics Data System (ADS)

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.

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

2013-01-01

178

Comparison of two electrokinetic methods – electroosmosis and streaming potential – to determine the zeta-potential of plane ceramic membranes  

Microsoft Academic Search

Electroosmotic flow rate and streaming potential measurements are used to characterise electrokinetic properties of plane ceramic membranes. The study is carried out at different pH, ionic strengths and electrolytes. Effects of pH and ionic strength are studied for both techniques which lead to very close values of isoelectric points. The specific adsorption of Ca2+ cations is observed with the two

A Szymczyk; P Fievet; M Mullet; J. C Reggiani; J Pagetti

1998-01-01

179

Cost-effective bioregeneration of nitrate-laden ion exchange brine through deliberate bicarbonate incorporation.  

PubMed

Bioregeneration of nitrate-laden ion exchange brine is desired to minimize its environmental impacts, but faces common challenges, i.e., enriching sufficient salt-tolerant denitrifying bacteria and stabilizing brine salinity and alkalinity for stable brine biotreatment and economically removing undesired organics derived in biotreatment. Incorporation of 0.25 M bicarbonate in 0.5 M chloride brine little affected resin regeneration but created a benign alkaline condition to favor bio-based brine regeneration. The first-quarter sulfate-mainly enriched spent brine (SB) was acidified with carbon source acetic acid for using CaCl2 at an efficiency >80% to remove sulfate. Residual Ca(2+) was limited below 2 mM by re-mixing the first-quarter and remained SB to favor denitrification. Under [Formula: see text] system buffered pH condition (8.3-8.8), nitrate was removed at 0.90 gN/L/d by hematite-enriched well-settled activated sludge (SVI 8.5 ml/g) and the biogenic alkalinity was retained as bicarbonate. The biogenic alkalinity met the need of alkalinity in removing residual Ca(2+) after sulfate removal and in CaCl2-induced CaCO3 flocculation to remove 63% of soluble organic carbon (SOC) in biotreated brine. Carbon-limited denitrification was also operated after activated sludge acclimation with sulfide to cut SOC formation during denitrification. Overall, this bicarbonate-incorporation approach, stabilizing the brine salinity and alkalinity for stable denitrification and economical removal of undesired SOC, suits long-term cost-effective brine bioregeneration. PMID:25746960

Li, Qi; Huang, Bin; Chen, Xin; Shi, Yi

2015-05-15

180

Incorporating translational research with clinical research to increase effectiveness in healthcare for better health  

PubMed Central

Background The transfer of new scientific discoveries into healthcare interventions requires that basic and clinical researchers work together with health care providers to generate team science. These innovative models require translational teams, and need to extend beyond the academic environment. The future of translational science requires partnerships with the healthcare community as well as the broader, general community. This new integrated model of effective translational teams holds promise for addressing thorny and persistent health disparities, is consistent with the nation’s strategic priority of eliminating health disparities, and bodes well for increasing healthcare effectiveness aimed at better health for all. Discussion As part of the 13th Research Centers in Minority Institutions (RCMI) International Symposium on Health Disparities, several senior academic leaders joined efforts to hold a workshop to discuss a model that considers the incorporation of two translational research strategies in research career development programs: Comparative effectiveness research (CER) and community-based participatory research (CBPR) for increasing healthcare effectiveness and eliminating healthcare disparities. Discussion included what issues may be most germane to the concept of a unified model for research workforce development through formal training and career development leading to increased effectiveness in healthcare for better health. Summary We believe that there is a gap in knowledge and skills in formal research career development programs that will enable physicians, other clinicians, and basic scientists to actively participate in these two translational research strategies. The purpose of this paper is to share the outcomes of these discussions, and encourage further discussion and possible innovation in the formulation of a new model for translational research workforce development. PMID:25024819

2014-01-01

181

Micromolded polymer electrokinetic separation systems with variable volume sampling and integrated optical and conductivity detection  

NASA Astrophysics Data System (ADS)

The micromoulding of polymers has provided an ideal fabrication route for the construction of single-use integrated devices for electrokinetic microseparations. Our designs have incorporated injector geometry that allows variable injection volumes in microchannels controlled by a combination of programmed hydrodynamics and electrophoresis. The utility of the injection scheme is demonstrated for isotachophoresis separations. Further developments have lead to the incorporation of parallel opposed conductivity detection electrodes in two ways. Firstly, by the injection of conducting polymer into a pre-molded channel system and secondly through the molding of the polymer microchannels around electrodes pre-molded in conducting polymer. This has provided a potential rapid manufacturing route for low cost polymer separation devices. As well as integrated conductivity detection electrodes, simple optical elements have been incorporated into injection molded ITP devices to permit detection of the separated bands by optical means. A simple spherical lens was incorporated into the top section of the device which included the sample and buffer reservoirs. The lens was positioned directly above the conductivity detection electrodes, to permit simultaneous electrochemical and optical detection. The lens was used to perform visible absorption spectroscopy using an Ocean Optics spectrography and tungsten-halogen fiber-optic white light source.

Fielden, Peter R.; Baldock, Sara J.; Goddard, Nick J.; Morrison, Lee; Prest, Jeff E.; Treves Brown, Bernard J.; Zgraggen, Michele

2002-06-01

182

The effectiveness of incorporating a real-time oculometer system in a commercial flight training program  

NASA Technical Reports Server (NTRS)

The effectiveness of incroporating a real-time oculometer system into a Boeing 737 commercial flight training program was studied. The study combined a specialized oculometer system with sophisticated video equipment that would allow instructor pilots (IPs) to monitor pilot and copilot trainees' instrument scan behavior in real-time, and provide each trainee with video tapes of his/her instrument scanning behavior for each training session. The IPs' performance ratings and trainees' self-ratings were compared to the performance ratings by IPs and trainees in a control group. The results indicate no difference in IP ratings or trainees' self-ratings for the control and experimental groups. The results indicated that the major beneficial role of a real-time oculometer system for pilots and copilots having a significant amount of flight experience would be for problem solving or refinement of instrument scanning behavior rather than a general instructional scheme. It is suggested that this line of research be continued with the incorporation of objective data (e.g., state of the aircraft data), measures of cost effectiveness and with trainees having less flight experience.

Jones, D. H.; Coates, G. D.; Kirby, R. H.

1983-01-01

183

Incorporating haptic effects into three-dimensional virtual environments to train the hemiparetic upper extremity  

PubMed Central

Current neuroscience has identified several constructs to increase the effectiveness of upper extremity rehabilitation. One is the use of progressive, skill acquisition-oriented training. Another approach emphasizes the use of bilateral activities. Building on these principles, this paper describes the design and feasibility testing of a robotic / virtual environment system designed to train the arm of persons who have had strokes. The system provides a variety of assistance modes, scalable workspaces and hand-robot interfaces allowing persons with strokes to train multiple joints in three dimensions. The simulations utilize assistance algorithms that adjust task difficulty both online and offline in relation to subject performance. Several distinctive haptic effects have been incorporated into the simulations. An adaptive master-slave relationship between the unimpaired and impaired arm encourages active movement of the subject's hemiparetic arm during a bimanual task. Adaptive anti-gravity support and damping stabilize the arm during virtual reaching and placement tasks. An adaptive virtual spring provides assistance to complete the movement if the subject is unable to complete the task in time. Finally, haptically rendered virtual objects help to shape the movement trajectory during a virtual placement task. A proof of concept study demonstrated this system to be safe, feasible and worthy of further study. PMID:19666345

Adamovich, Sergei; Fluet, Gerard G.; Merians, Alma S.; Mathai, Abraham; Qiu, Qinyin

2010-01-01

184

Economic impacts of noxious facilities: Incorporating the effects of risk aversion  

SciTech Connect

Developing new sites for noxious facilities has become a complex process with many potential pitfalls. In addition to the need to negotiate conditions acceptable to the host community, siting success may depend on the facility proposer`s ability to identify a candidate site that not only meets technical requirements, but that is located in a community or region whose population is not highly averse to the risks associated with the type of facility being proposed. Success may also depend on the proposer accurately assessing potential impacts of the facility and offering an equitable compensation package to the people affected by it. Facility impact assessments, as typically performed, include only the effects of changes in population, employment and economic activity associated with facility construction and operation. Because of their scope, such assessments usually show a short-run, net economic benefit for the host region, making the intensely negative public reaction to some types and locations of facilities seem unreasonable. The impact component excluded from these assessments is the long-run economic effect of public perceptions of facility risk and nuisance characteristics. Recent developments in psychological and economic measurement techniques have opened the possibility of correcting this flaw by incorporating public perceptions in projections of economic impacts from noxious facilities.

Nieves, L.A.

1993-09-01

185

Effects of incorporation of hydroxyapatite and fluoroapatite nanobioceramics into conventional glass ionomer cements (GIC).  

PubMed

Hydroxyapatite (HA) has excellent biological behavior, and its composition and crystal structure are similar to the apatite in the human dental structure and skeletal system; a number of researchers have attempted to evaluate the effect of the addition of HA powders to restorative dental materials. In this study, nanohydroxy and fluoroapatite were synthesized using an ethanol based sol-gel technique. The synthesized nanoceramic particles were incorporated into commercial glass ionomer powder (Fuji II GC) and were characterized using Fourier transform infrared and Raman spectroscopy, X-ray diffraction and scanning electron microscopy. Compressive, diametral tensile and biaxial flexural strengths of the modified glass ionomer cements were evaluated. The effect of nanohydroxyapatite and fluoroapatite on the bond strength of glass ionomer cement to dentin was also investigated. Results showed that after 1 and 7 days of setting, the nanohydroxyapatite/fluoroapatite added cements exhibited higher compressive strength (177-179MPa), higher diametral tensile strength (19-20MPa) and higher biaxial flexural strength (26-28MPa) as compared with the control group (160MPa in CS, 14MPa in DTS and 18MPa in biaxial flexural strength). The experimental cements also exhibited higher bond strength to dentin after 7 and 30 days of storage in distilled water. It was concluded that glass ionomer cements containing nanobioceramics are promising restorative dental materials with both improved mechanical properties and improved bond strength to dentin. PMID:17921077

Moshaverinia, Alireza; Ansari, Sahar; Moshaverinia, Maryam; Roohpour, Nima; Darr, Jawwad A; Rehman, Ihtesham

2008-03-01

186

A non-classical Kirchhoff plate model incorporating microstructure, surface energy and foundation effects  

NASA Astrophysics Data System (ADS)

A new non-classical Kirchhoff plate model is developed using a modified couple stress theory, a surface elasticity theory and a two-parameter elastic foundation model. A variational formulation based on Hamilton's principle is employed, which leads to the simultaneous determination of the equations of motion and the complete boundary conditions and provides a unified treatment of the microstructure, surface energy and foundation effects. The new plate model contains a material length scale parameter to account for the microstructure effect, three surface elastic constants to describe the surface energy effect, and two foundation moduli to represent the foundation effect. The current non-classical plate model reduces to its classical elasticity-based counterpart when the microstructure, surface energy and foundation effects are all suppressed. In addition, the newly developed plate model includes the models considering the microstructure dependence or the surface energy effect or the foundation influence alone as special cases and recovers the Bernoulli-Euler beam model incorporating the microstructure, surface energy and foundation effects. To illustrate the new model, the static bending and free vibration problems of a simply supported rectangular plate are analytically solved by directly applying the general formulas derived. For the static bending problem, the numerical results reveal that the deflection of the simply supported plate with or without the elastic foundation predicted by the current model is smaller than that predicted by the classical model. Also, it is observed that the difference in the deflection predicted by the new and classical plate models is very large when the plate thickness is sufficiently small, but it is diminishing with the increase of the plate thickness. For the free vibration problem, it is found that the natural frequency predicted by the new plate model with or without the elastic foundation is higher than that predicted by the classical plate model, and the difference is significant for very thin plates. These predicted trends of the size effect at the micron scale agree with those observed experimentally. In addition, it is shown both analytically and numerically that the presence of the elastic foundation reduces the plate deflection and increases the plate natural frequency, as expected.

Gao, X.-L.; Zhang, G. Y.

2015-02-01

187

in the future. Nelson [13] makes a coherent and eloquent plea for incorporating more effective (and interesting)  

E-print Network

in the future. Nelson [13] makes a coherent and eloquent plea for incorporating more effective (and, Nelson [13] has done pioneering work on the advantages of active (versus passive) instructional methods thinking to understanding life on Earth. References 1 Nelson, C.E. (2007) Teaching evolution effectively

Zhang, Jianzhi

188

Oxygen incorporation in AllnP, and its effect on P-type doping with magnesium  

NASA Astrophysics Data System (ADS)

Oxygen incorporation in AlyIn1-yP (y ˜ 0.5) grown by metalorganic chemical vapor deposition (MOCVD) has been studied as a function of PH3 flow, growth temperature, and alloy composition. Both O2 and diethylaluminum ethoxide (DEAlO) were employed as sources of oxygen. The incorporation of oxygen was found to be a superlinear function of O2 or DEAlO flow. When multiple sources of oxygen are present, a surface interaction leads to enhanced oxygen incorporation. Oxygen incorporation cannot be adequately described by a simple dependence on growth temperature or V/III ratio due to strong interactions between these variables. In Mg-doped AlInP co-doped with oxygen, the incorporation of both Mg and O is strongly affected by an interaction between the two species, and roughly 10% of the oxygen atoms act as compensating donors.

Stockman, S. A.; Huang, J.-W.; Osentowski, T. D.; Chui, H. C.; Peanasky, M. J.; Maranowski, S. A.; Grillot, P. N.; Moll, A. J.; Chen, C. H.; Kuo, C. P.; Liang, B. W.

1999-07-01

189

Capillary electrokinetic separations: Influence of mobile phase composition on performance  

SciTech Connect

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.

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

1990-01-01

190

MICELLAR ELECTROKINETIC CHROMATOGRAPHY-MASS SPECTROMETRY (R823292)  

EPA Science Inventory

The combination of micellar electrokinetic chromatography (MEKC) with mass spectrometry (MS) is very attractive for the direct identification of analyte molecules, for the possibility of selectivity enhancement, and for the structure confirmation and analysis in a MS-MS mode. The...

191

Spatially controlled microfluidics using low-voltage electrokinetics  

Microsoft Academic Search

Most electrokinetic microfluidic devices currently require high voltages (>50 V) to generate sustained electric fields. However, two long-standing limitations remain, namely: (i) the resulting electrolysis of water produces bubbles, forcing electrodes to be placed in reservoirs outside the channels, and (ii) direct integration with low-voltage microelectronics cannot be achieved. A further limitation is the lack of spatial control within the

Katherine A. Dunphy Guzmán; Rohit N. Karnik; John S. Newman; Arun Majumdar

2006-01-01

192

Enhanced electrokinetic remediation of contaminated manufactured gas plant soil  

Microsoft Academic Search

This paper evaluates different flushing agents to enhance the efficiency of electrokinetic remediation of a manufactured gas plant (MGP) soil contaminated with polycyclic aromatic hydrocarbons (PAHs) and heavy metals. Because of high concentrations, PAHs were of environmental concern and required to be removed to acceptable levels. Four flushing agents, which included two surfactants (3% Tween 80, and 5% Igepal CA-720),

Krishna R. Reddy; Prasanth R. Ala; Saurabh Sharma; Surendra N. Kumar

2006-01-01

193

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

NASA Astrophysics Data System (ADS)

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.

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

2010-05-01

194

Effects of fission product incorporation on the microstructure of cubic zirconia  

NASA Astrophysics Data System (ADS)

Cesium, iodine and strontium ions have been implanted into yttria-stabilized cubic zirconia (YSZ) to determine the effects of fission product incorporation in YSZ that is considered as an inert nuclear fuel matrix. The ion implantation was conducted at room temperature to 1×10 21 ions/m 2 for each ion with ion energies ranging from 70 to 400 keV. The peak displacement damage level and the peak ion concentration in YSZ reached 205-330 displacement per atoms (dpa) and 11-26 at.%, respectively. The microstructure of the implanted YSZ was studied by in situ and cross-sectional transmission electron microscopy (TEM). In the iodine and strontium implanted samples, a damaged layer with a high density of defect clusters was observed, while in the cesium implanted specimen, most of the damaged layer is amorphous.Nanocrystalline precipitates were observed in the strontium implanted specimen after annealing at 1273 K. The results are discussed in terms of the ionic size, mobility and the solubility of the implanted species in YSZ.

Wang, L. M.; Wang, S. X.; Zhu, S.; Ewing, R. C.

2001-02-01

195

Powerful tests for association on quantitative trait loci incorporating imprinting effects.  

PubMed

Genomic imprinting is an important epigenetic factor in complex traits study, and there has recently been considerable interest in association study for quantitative traits by incorporating imprinting. However, these methods need the assumptions of Hardy-Weinberg equilibrium or only use information from families with one child. In this paper, by taking imprinting into account and making no assumption about the distribution of the quantitative traits, we propose two novel classes of Q-C-TDTI(c) and Q-C-MAX(c) family-based association tests for quantitative traits. The tests flexibly accommodate family data with missing parental genotype and with multiple siblings. Q-C-TDTI(c) is derived from a two-stage analysis, where in the first stage Q-C-PAT(c) is applied to test for imprinting effects and in the second stage we select the most appropriate statistic among three transmission disequilibrium tests for association according to the finding from Q-C-PAT(c). Another proposed Q-C-MAX(c) approach takes the maximum of the three statistics. Compared with the existing alternative methods, the simulation results demonstrate that the two proposed tests are robust to population stratification and have better performance for testing association under various scenarios. Further, the powerful and versatile Q-C-TDTI(c) test is applied to analyze Framingham Heart Study data. PMID:23552672

Xia, Fan; Zhou, Ji-Yuan; Fung, Wing Kam

2013-06-01

196

The effect of nitrogen incorporation in DLC films deposited by ECR Microwave Plasma CVD  

NASA Astrophysics Data System (ADS)

Diamond like carbon (DLC) and nitrogenated diamond like carbon (DLC:N) films have been deposited by electron cyclotron resonance microwave plasma chemical vapor deposition (ECR-MP CVD) on Si (1 1 0), steel and glass substrates, using CH4 and N2 as plasma source. The effect of nitrogen doping on the optical, electrical, structural and mechanical properties of films was investigated. X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR) and Raman spectroscopy results showed that sp2 bonded carbon phases increased while the sp3 bonded carbon phases decreased by nitrogen doping. Microhardness measurements showed a decrease in hardness (from 75 to 69 GPa) according to nitrogen incorporation. Average transmittance of all the films was over 90% and band gap energy (Eg) of the films decreased due to increasing nitrogen flow rate. The film morphology was studied using the atomic force microscopy (AFM). Electrical properties were characterized by Hall measurement. Undoped DLC was p-type with a conductivity of 9.81 × 10-6 (? cm)-1. DLC films became n-type by nitrogen doping. The best conductivity value for the nitrogen doped DLC films was found 2.77 × 10-5 (? cm)-1. PL spectra of DLC and DLC:N films showed three peaks at 405 nm (3.06 eV), 533 nm (2.32 eV) and 671 nm (1.84 eV).

Seker, Z.; Ozdamar, H.; Esen, M.; Esen, R.; Kavak, H.

2014-09-01

197

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

PubMed

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

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

2015-04-01

198

Electrokinetic-enhanced bioaugmentation for remediation of chlorinated solvents contaminated clay  

PubMed Central

Successful bioremediation of contaminated soils is controlled by the ability to deliver bioremediation additives, such as bacteria and/or nutrients, to the contaminated zone. Because hydraulic advection is not practical for delivery in clays, electrokinetic (EK) injection is an alternative for efficient and uniform delivery of bioremediation additive into low-permeability soil and heterogeneous deposits. EK–enhanced bioaugmentation for remediation of clays contaminated with chlorinated solvents is evaluated. Dehalococcoides (Dhc) bacterial strain and lactate ions are uniformly injected in contaminated clay and complete dechlorination of chlorinated ethene is observed in laboratory experiments. The injected bacteria can survive, grow, and promote effective dechlorination under EK conditions and after EK application. The distribution of Dhc within the clay suggests that electrokinetic transport of Dhc is primarily driven by electroosmosis. In addition to biodegradation due to bioaugmentation of Dhc, an EK-driven transport of chlorinated ethenes is observed in the clay, which accelerates cleanup of chlorinated ethenes from the anode side. Compared with conventional advection-based delivery, EK injection is significantly more effective forestablis hingmicrobial reductive dechlorination capacity in low-permeability soils. PMID:22365139

Mao, Xuhui; Wang, James; Ciblak, Ali; Cox, Evan E.; Riis, Charlotte; Terkelsen, Mads; Gent, David B.; Alshawabkeh, Akram N.

2012-01-01

199

Effects of vestibular nerve transection on the calcium incorporation of fish otoliths  

NASA Astrophysics Data System (ADS)

Previous investigations revealed that the growth of fish inner ear otoliths (otolith size and calcium-incorporation) depends on the amplitude and the direction of gravity, suggesting the existence of a (negative) feedback mechanism. In search for the regulating unit, the vestibular nerve was transected unilaterally in neonate swordtail fish ( Xiphophorus helleri) which were subsequently incubated in the calcium-tracer alizarin-complexone. Calcium incorporation ceased on the transected head sides, indicating that calcium uptake is neurally regulated.

Anken, Ralf H.; Edelmann, Elke; Rahmann, Hinrich

2001-08-01

200

Inhibitory Effect of Solar Radiation on Thymidine and Leucine Incorporation by Freshwater and Marine Bacterioplankton  

Microsoft Academic Search

a concentrations were higher than those in the upper water column, the rates of incorporation of (3H)TdR were higher in those samples exposed to full sunlight or to UV-A plus PAR than in the dark control. In laboratory experiments with artificial UV light, the incorporation of (3H)TdR and (14C)Leu by mixed bacterial lake cultures was also inhibited mainly by UV-A.

RUBEN SOMMARUGA; INGRID OBERNOSTERER; GERHARD J. HERNDL

1997-01-01

201

On-line preconcentration of sodium dodecyl sulfate-protein complexes using electrokinetic supercharging method with a prefilled water plug in capillary sieving electrophoresis.  

PubMed

An electrokinetic supercharging (EKS) method with a prefilled water plug at the head column of capillary was developed for on-line preconcentration of sodium dodecyl sulfate (SDS)-protein complexes in capillary sieving electrophoresis (CSE). Conventional EKS is a combination of electrokinetic injection with transient isotachophoresis (tr-ITP). The capillary is first filled with background electrolyte, then an appropriate amount of a leading electrolyte is filled and electro-injection is carried out for certain duration. After that, terminating electrolyte is filled, and tr-ITP is subsequently initiated, followed by capillary electrophoresis (CE) separation. In this work, the performance of EKS was evaluated by integrating multiple sub-methods step by step, and a water plug containing polymer was introduced before electrokinetic injection in order to further improve the concentration effect. The positive effects of the sub-methods were verified, including molecular sieving effect of polymer, field enhanced sample injection (FESI) with and without a water plug, and transient isotachophoretic electrophoresis-based FESI. It was observed that analyte discrimination usually encountered in conventional electrokinetic injection was eliminated due to the similar charge to mass ratios of SDS-protein complexes. Based on these results, a hybrid on-line preconcentration method, EKS with injecting a water plug containing polymer before sample electrokinetic injection, was proposed and used to indiscriminately preconcentrate SDS-protein complexes, which provided a sensitivity enhancement factor of more than 1000. It was very suitable for the analysis of low-abundance proteins, providing the information of their molecular mass. PMID:22233073

Liu, Jing; Kang, Mingchao; Liu, Zhen

2011-09-01

202

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

SciTech Connect

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.

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

1995-09-01

203

Fluorapatite surface composition in aqueous solution deduced from potentiometric, electrokinetic, and solubility measurements, and spectroscopic observations  

NASA Astrophysics Data System (ADS)

The surface chemistry of fluorapatite in aqueous solution was investigated using electrokinetic techniques, potentiometric titrations, solubility measurements, and attenuated total reflection infrared spectroscopy. All methods indicate the formation of Ca/F depleted, P enriched altered layer via exchange reactions between H + and Ca 2+, and OH - and F - at the fluorapatite (FAP) surface. Observations suggest that this leached layer has a di-calcium phosphate (CaHPO 4) composition and that it controls the apparent solubility of FAP. Electrokinetic measurements yield an iso-electric point value of 1 ± 0.5 consistent with a negatively charged FAP surface at pH > 1. In contrast, surface titrations give an apparent pH of point of zero charge of ˜7.7, consistent with a positively charged surface at pH < 7.7. These differences are shown to stem from proton consumption by both proton exchange and dissolution reactions at the FAP surface. After taking account for these effects, FAP surface charge is shown to be negative to at least pH 4 by surface titration analysis.

Chaïrat, Claire; Oelkers, Eric H.; Schott, Jacques; Lartigue, Jean-Eric

2007-12-01

204

Application of electrokinetics for stimulating microbial clean-up of contaminated soils  

NASA Astrophysics Data System (ADS)

Given sufficient time there are few synthetic compounds that can resist microbial degradation, a fact exploited in environmental clean-up. Despite this the performance of micro-organisms in remedial technologies is often sub-optimal. There are many reasons for the failure of indigenous microbial communities to reduce contaminant concentrations, including issues of bioavailability and the inability of the contaminants to switch on genes (catabolic) responsible for contaminant degradation. Even if the presence of the required catabolic genes is confirmed, there continues to be a significant need to develop procedures to stimulate their activity. We have investigated the potential of soil electrokinetics (3-4 A m-2) to stimulate microbial degradation of organic pollutants and move the soil contaminants relative to the degradative microorganisms, so increasing contact between the two components. Using soils contaminated with pentachlorophenol as our model laboratory system, we have demonstrated that the technique is effective at causing gross and controlled movement of PCP through soils at the laboratory-scale. It can also stimulate rates (up to 25% over that of the control) by which introduced bacteria degrade the contaminant. The additional potential benefits of electrokinetics in regard to stimulating microbial activity and soil clean-up will be discussed.

Thompson, I.; Lear, G.

2006-05-01

205

The Effect of Incorporation of HNO(sub 3) Into Liquid Sulfuric Acid on Heterogeneous Reaction Probabilities  

NASA Technical Reports Server (NTRS)

Using a fast-flow reactor coupled to a quadrupole mass spectrometer, the heterogeneous reactions of C1ONO2 + HCl and HOCl + HCl as well as hydrolysis of N2O5 and C1ONO2 were investigated on liquid sulfuric acid, with particular emphasis on the effect of incorporation of HNO3 on the reaction probabilities.

Zhang, R.; Leu, M-T.; Keyser, L.

1994-01-01

206

Effects of Ingredient Incorporation into Sausage Meat on the Micellarisation and uptake of ?-tocopherol by Caco-2 Human Intestinal Cells  

Microsoft Academic Search

Ingredients are incorporated into meat and meat products to produce a ``healthier'' product. However, the effect of ingredient addition on availability of nutrients endogenous to foods is generally not considered. This study investigated the availability and cellular uptake of ?-tocopherol from supplemented sausages with the aid of an in vitro digestion procedure coupled with a Caco-2 cell model. Sausages were

O. Kenny; Y. OCallaghan; N. M. OBrien

2008-01-01

207

The Effect of an Instructional Unit Incorporating Live Animals on Knowledge of Nutrition for Different Age Levels.  

ERIC Educational Resources Information Center

A nutrition education unit, Rat Pak, developed by Dairy Council, Inc., is an attempt to influence students to make wise food choices. It consists of eleven lessons in an instructional sequence which incorporates the use of white rats as a means of illustrating the effect of improper diet while teaching proper diet. The purpose of this…

Roth, Anne I.; Wunderlich, Kenneth W.

208

Synergistic effects of dimethyloxalylglycine and butyrate incorporated into ?-calcium sulfate on bone regeneration.  

PubMed

Osteogenesis is closely related to angiogenesis, and the combined delivery of angiogenic and osteogenic factors has been suggested to enhance bone regeneration. Small molecules have been explored as alternatives to growth factors for tissue regeneration applications. In this study, we examined the effects of the combined application of angiogenic and osteogenic small molecules on bone regeneration using a prolyl hydroxylase, dimethyloxalylglycine (DMOG), and a histone deacetylase inhibitor, butyrate. In a critical size bone defect model in rats, DMOG and butyrate, which were incorporated into ? calcium sulfate (?CS), resulted in synergistic enhancements in bone and blood vessel formation, eventually leading to bone healing, as confirmed by micro-CT and histological analyses. In MC4 pre-osteoblast cultures, DMOG and butyrate enhanced the pro-angiogenic responses and osteoblast differentiation, respectively, which were evaluated based on the levels of hypoxia inducible factor (HIF)-1? protein and the expression of pro-angiogenic molecules (VEGF, home oxidase-1, glucose transporter-1) and by alkaline phosphatase (ALP) activity and the expression of osteoblast phenotype marker molecules (ALP, ?1(I)col, osteocalcin, and bone sialoprotein). DMOG combined with butyrate synergistically improved osteoblast differentiation and pro-angiogenic responses, the levels of which were drastically increased in the cultures on ?CS disks. Furthermore, it was demonstrated that ?CS increased the level of HIF-1? and as a consequence VEGF expression, and supported osteoblast differentiation through the release of calcium ions from the ?CS. Altogether, the results of this study provide evidence that a combination treatment with the small molecules DMOG and butyrate can expedite the process of bone regeneration and that ?CS can be an efficient delivery vehicle for the small molecules for bone regeneration. PMID:25477166

Woo, Kyung Mi; Jung, Hong-Moon; Oh, Joung-Hwan; Rahman, Saeed Ur; Kim, Soung Min; Baek, Jeong-Hwa; Ryoo, Hyun-Mo

2015-01-01

209

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

SciTech Connect

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.

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

210

Effects of Wheat Straw Incorporation on the Availability of Soil Nutrients and Enzyme Activities in Semiarid Areas  

PubMed Central

Soil infertility is the main barrier to dryland agricultural production in China. To provide a basis for the establishment of a soil amelioration technical system for rainfed fields in the semiarid area of northwest China, we conducted a four—year (2007–2011) field experiment to determine the effects of wheat straw incorporation on the arid soil nutrient levels of cropland cultivated with winter wheat after different straw incorporation levels. Three wheat straw incorporation levels were tested (H: 9000 kg hm-2, M: 6000 kg hm-2, and L: 3000 kg hm-2) and no straw incorporation was used as the control (CK). The levels of soil nutrients, soil organic carbon (SOC), soil labile organic carbon (LOC), and enzyme activities were analyzed each year after the wheat harvest. After straw incorporation for four years, the results showed that variable straw amounts had different effects on the soil fertility indices, where treatment H had the greatest effect. Compared with CK, the average soil available N, available P, available K, SOC, and LOC levels were higher in the 0–40 cm soil layers after straw incorporation treatments, i.e., 9.1–30.5%, 9.8–69.5%, 10.3–27.3%, 0.7–23.4%, and 44.4–49.4% higher, respectively. On average, the urease, phosphatase, and invertase levels in the 0–40 cm soil layers were 24.4–31.3%, 9.9–36.4%, and 42.9–65.3% higher, respectively. Higher yields coupled with higher nutrient contents were achieved with H, M and L compared with CK, where these treatments increased the crop yields by 26.75%, 21.51%, and 7.15%, respectively. PMID:25880452

Wei, Ting; Zhang, Peng; Wang, Ke; Ding, Ruixia; Yang, Baoping; Nie, Junfeng; Jia, Zhikuan; Han, Qingfang

2015-01-01

211

Effects of vascular bundle implantation on autograft, fresh-frozen allograft, and xenograft incorporation in a rabbit model.  

PubMed

This study examined the effects of vascular bundle implantation into a bone graft. Vascularized and nonvascularized autografts, allografts, and xenografts were placed inside defects in the proximal tibia in rabbits. Evaluation using radiographs, magnetic resonance imaging, bone scintigraphy, and microscopy showed autografts fused more rapidly than allografts and xenografts, and the majority of the vascularized grafts were incorporated completely. Autografts emerged as the gold standard. These findings indicate vessel implantation enhances and accelerates vascularization, new bone formation, and incorporation in autografts, allografts, and xenografts. PMID:19292207

Ozyurek, Ayhan; Leblebicioglu, Gursel; Bilgili, Hasan; Kurum, Baris; Gedikoglu, Gokhan; Atasever, Tamer; Tacal, Tugra; Doral, Mahmut Nedim

2008-02-01

212

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...

213

In vitro Study of the Effect of Clotrimazole Incorporation into Silicone Soft Liner on Fungal Colonization  

Microsoft Academic Search

Statement of Problem: Candidal colonization on soft liners is important in the development of pathogenesis, such as denture stomatitis. It has heen reported that combining anti-fungal agents into soft liners might be used in treatment and prevention of denture stomatitis. Purpose: The aim of this in-vitro study was to determine whether incorporating clotrimazole (C) into the silicone soft liner (S),

214

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...

215

The Perceived Effect of Time on HIV/AIDS Identity Incorporation  

ERIC Educational Resources Information Center

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.…

Baumgartner, Lisa M.

2012-01-01

216

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

ERIC Educational Resources Information Center

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,…

Baumgartner, Lisa M.

2012-01-01

217

Effect of coenzyme Q(10) incorporation on the characteristics of nanoliposomes.  

PubMed

Coenzyme Q(10) (CoQ(10)) is incorporated in nanoliposomes composed of egg yolk phospholipid, cholesterol, and Tween 80. Atomic force microscopy, performed to characterize vesicle surface topology, shows some visible influence of CoQ(10) on the nanoliposomal structure. CoQ(10) incorporation can suppress the increase of the z-average diameter of nanoliposomes during storage for 8 months at 4 degrees C. The liposomal lipid peroxidation caused by Fe(III)/ascorbate is also significantly inhibited. Perturbation of acyl chain motion of lipids due to the presence of CoQ(10) in the bilayer is examined by fluorescence probe diphenyl-hexatriene and Raman spectroscopy. Fluorescence probe studies indicate that CoQ(10) incorporation results in the microviscosity increase of nanoliposomes. The steric structure of nanoliposomes reflected by Raman spectroscopy changes obviously and shows CoQ(10) content dependency. The order parameters for the lateral interaction between chains increase. The trans conformation decrease and the gauche conformation increase as the weight contents of CoQ(10) incorporation are at 1%, 5%, 10%, and 32.5%. However, the order parameters for the longitudinal interaction in chains was higher than that of pure nanoliposomes as the weight content of CoQ(10) is at 25%. Results suggest that CoQ(10)might intercalate between lipid molecules and perturb the bilayer structure. PMID:17288474

Xia, Shuqin; Xu, Shiying; Zhang, Xiaoming; Zhong, Fang

2007-03-01

218

Effect of surface incorporation of broiler litter applied to no-till cotton on runoff quality  

Technology Transfer Automated Retrieval System (TEKTRAN)

A 2-yr field study was conducted on an Atwood silt loam (fine-silty, mixed, thermic Typic Paleudalfs) marginal upland soil to evaluate if incorporation of broiler litter into the soil surface in a no-till cotton affect runoff nutrient concentrations. The treatments consisted of 7.8 Mg ha-1 broiler l...

219

Testing and evaluation of electrokinetic decontamination of concrete  

SciTech Connect

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.

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

1996-10-01

220

Modeling Electrokinetic Flows by the Smoothed Profile Method  

PubMed Central

We propose an efficient modeling method for electrokinetic flows based on the Smoothed Profile Method (SPM) [1–4] and spectral element discretizations. The new method allows for arbitrary differences in the electrical conductivities between the charged surfaces and the the surrounding electrolyte solution. The electrokinetic forces are included into the flow equations so that the Poisson-Boltzmann and electric charge continuity equations are cast into forms suitable for SPM. The method is validated by benchmark problems of electroosmotic flow in straight channels and electrophoresis of charged cylinders. We also present simulation results of electrophoresis of charged microtubules, and show that the simulated electrophoretic mobility and anisotropy agree with the experimental values. PMID:20352076

Luo, Xian; Beskok, Ali; Karniadakis, George Em

2010-01-01

221

Feasibility of electrokinetic soil remediation in horizontal Lasagna cells.  

PubMed

An integrated soil remediation technology called Lasagna has been developed that combines electrokinetics with treatment zones for use in low permeability soils where the rates of hydraulic and electrokinetic transport are too low to be useful for remediation of contaminants. The technology was developed by two groups, one involving industrial partners and the DOE and another involving US EPA and the University of Cincinnati, who pursued different electrode geometries. The Industry/DOE group has demonstrated the technology using electrodes and treatment zones installed vertically from the soil surface. We have demonstrated the feasibility of installing horizontal electrodes and treatment zones in subsurface soils by hydraulic fracturing, a process that we adapted from petroleum industry practices. When horizontal electrodes were connected to a dc power supply, uniform electrical potential gradients of 10-40 V/m were created in soil between the electrodes, inducing electroosmotic flow that facilitated movement of water and contaminants into treatment zones between the electrodes. PMID:10946126

Roulier, M; Kemper, M; Al-Abed, S; Murdoch, L; Cluxton, P; Chen, J; Davis-Hoover, W

2000-10-01

222

Effect of crop residue incorporation on soil organic carbon (SOC) and greenhouse gas (GHG) emissions in European agricultural soils  

NASA Astrophysics Data System (ADS)

Soil organic matter (SOM) improves soil physical (e.g. increased aggregate stability), chemical (e.g. cation exchange capacity) and biological (e.g. biodiversity, earthworms) properties. The sequestration of soil organic carbon (SOC) may mitigate climate change. However, as much as 25-75% of the initial SOC in world agricultural soils may have been lost due to intensive agriculture (Lal, 2013). The European Commission has described the decline of organic matter (OM) as one of the major threats to soils (COM(2006) 231). Incorporation of crop residues may be a sustainable and cost-efficient management practice to maintain the SOC levels and to increase soil fertility in European agricultural soils. Especially Mediterranean soils that have low initial SOC concentrations, and areas where stockless croplands predominate may be suitable for crop residue incorporation. In this study, we aim to quantify the effects of crop residue incorporation on SOC and GHG emissions (CO2 and N2O) in different environmental zones (ENZs, Metzger et al., 2005) in Europe. Response ratios for SOC and GHG emissions were calculated from pairwise comparisons between crop residue incorporation and removal. Specifically, we investigated whether ENZs, clay content and experiment duration influence the response ratios. In addition, we studied how response ratios of SOM and crop yields were correlated. A total of 718 response ratios (RR) were derived from a total of 39 publications, representing 50 experiments (46 field and 4 laboratory) and 15 countries. The SOC concentrations and stocks increased by approximately 10% following crop residue incorporation. In contrast, CO2 emissions were approximately six times and N2O emissions 12 times higher following crop residue incorporation. The effect of ENZ on the response ratios was not significant. For SOC concentration, the >35% clay content had significantly approximately 8% higher response ratios compared to 18-35% clay content. As the duration of the experiment rose, RR for SOC concentration and stock increased. For N2O emissions, RR was significantly higher in <5 years experiment duration compared to 11-15 years experiment duration. For GHG emissions, the RRs were significantly higher when vegetable crop residues were incorporated instead of cereal crop residues. No significant correlations were found between RR for SOC concentration and yields, but differences between sites could be detected. We conclude that crop residue incorporation is an important management practice for maintaining SOC concentrations and stocks. Its influence in increasing GHG emissions should not be overlooked as the data availability from field experiments on GHG emissions is still scarce.

Lehtinen, Taru; Schlatter, Norman; Baumgarten, Andreas; Bechini, Luca; Krüger, Janine; Grignani, Carlo; Zavattaro, Laura; Costamagna, Chiara; Spiegel, Heide

2014-05-01

223

Electrokinetic removal of Cu and Zn in anaerobic digestate: Interrelation between metal speciation and electrokinetic treatments.  

PubMed

In recent years, a potential controversy has arisen that whether the metal speciation in solid matrix determined its electrokinetic (EK) removal efficiency or by contrast. In present study, Cu and Zn in anaerobic digestate were selected as candidates to investigate the relation between the species of metal and EK treatment. The obtained results show that the removal efficiency for each fraction decreased in the order as follows: exchangeable?bound to carbonates>bound to Fe-Mn oxides>bound to organic matters>residual. For both Cu and Zn, their total removal performance was dependent on their dominant fraction in the digestate. A constant pH maintenance around the digestate via circulation of acid electrolyte is an optional operation because a strong acid atmosphere (pH<2) around the digestate can be formed automatically as EK time elapses. Despite that many reactions occurred during EK process, the species distribution of Cu and Zn in the digestate determined their total EK removal efficiency essentially. PMID:25562809

Zhu, Neng-Min; Chen, Mengjun; Guo, Xu-Jing; Hu, Guo-Quan; Yu-Deng

2015-04-01

224

Evaluation of Electrokinetic Remediation of Arsenic-contaminated Soils  

Microsoft Academic Search

The potential of electrokinetic (EK) remediation technology has been successfully demonstrated for the remediation of heavy\\u000a metal-contaminated fine-grained soils through laboratory scale and field application studies. Arsenic contamination in soil\\u000a is a serious problem affecting both site use and groundwater quality. The EK technology was evaluated for the removal of arsenic\\u000a from two soil samples; a kaolinite soil artificially contaminated

Soon-Oh Kim; Won-Seok Kim; Kyoung-Woong Kim

2005-01-01

225

Electrokinetic shape changes of cochlear outer hair cells  

Microsoft Academic Search

Rapid mechanical changes have been associated with electrical activity in a variety of non-muscle excitable cells1-5. Recently, mechanical changes have been reported in cochlear hair cells6-8. Here we describe electrically evoked mechanical changes in isolated cochlear outer hair cells (OHCs) with characteristics which suggest that direct electrokinetic phenomena are implicated in the response. OHCs make up one of two mechanosensitive

Bechara Kachar; William E. Brownell; Richard Altschuler; Jörgen Fex

1986-01-01

226

Separation of hydrophobic polymer additives by microemulsion electrokinetic chromatography  

Microsoft Academic Search

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,

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

2001-01-01

227

Evaluation of Electrokinetic Technique for Industrial Waste Decontamination  

Microsoft Academic Search

Several industrial activities produce large amounts of metal-polluted sludge, disposal of which could pose serious environmental and ecological problems because of the usual high content of mobile metals. In this work, an electrokinetic technique was used to reduce the high metal content of two industrial wastes: sludges from mining (SM) and from the iron-steel (SIS) industry. Initially, a physical-chemical characterization

M. Pazos; M. T. Alcántara; C. Cameselle; M. A. Sanromán

2009-01-01

228

Electrokinetic chromatography with micellar solution and open-tubular capillary  

Microsoft Academic Search

Fundamental characteristics of a new type of chromatography with micellar solutions of ionic surfactants were examined. Electrokinetic phenomena in open-tubular capillaries move two phases, aqueous and micellar, with different velocities and micellar solubilization operates as the distribution process of solutes. Sodium dodecyl sulfate (SDS) solutions and a 0.05 mm i.d. x 650 mm fused silica tube were employed and high

Shigeru. Terabe; Koji. Otsuka; Teiichi. Ando

1985-01-01

229

Effect of trestatin, an amylase inhibitor, incorporated into bread, on glycemic responses in normal and diabetic patients.  

PubMed

The effect of incorporating the pancreatic alpha-amylase inhibitor trestatin into bread on postprandial plasma glucose and insulin excursions was tested in healthy volunteers and non-insulin-dependent diabetic patients. At both dose levels of trestatin (3 and 6 mg/75 g starch) the peak values of plasma glucose and insulin were reduced markedly (compared with placebo) after the ingestion of 75 g starch in the form of bread. In healthy control subjects as well as in diabetic patients, trestatin produced significantly lower insulin excretions but also significant reductions in incremental plasma glucose areas in a dose-dependent fashion. It is concluded that it is technologically feasible to incorporate trestatin into starchy foods without loss of activity or impairment of taste. Furthermore, the positive effect of trestatin on glycemic and insulinemic responses in diabetics and the lack of serious side effects offer a great potential in the dietary treatment of diabetic patients. PMID:1701612

Golay, A; Schneider, H; Temler, E; Felber, J P

1991-01-01

230

Principles of Micellar Electrokinetic Capillary Chromatography Applied in Pharmaceutical Analysis  

PubMed Central

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

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

2013-01-01

231

Optimization of an electrokinetic mixer for microfluidic applications  

PubMed Central

This work is concerned with the investigation of the concentration fields in an electrokinetic micromixer and its optimization in order to achieve high mixing rates. The mixing concept is based on the combination of an alternating electrical excitation applied to a pressure-driven base flow in a meandering microchannel geometry. The electrical excitation induces a secondary electrokinetic velocity component, which results in a complex flow field within the meander bends. A mathematical model describing the physicochemical phenomena present within the micromixer is implemented in an in-house finite-element-method code. We first perform simulations comparable to experiments concerned with the investigation of the flow field in the bends. The comparison of the complex flow topology found in simulation and experiment reveals excellent agreement. Hence, the validated model and numerical schemes are employed for a numerical optimization of the micromixer performance. In detail, we optimize the secondary electrokinetic flow by finding the best electrical excitation parameters, i.e., frequency and amplitude, for a given waveform. Two optimized electrical excitations featuring a discrete and a continuous waveform are discussed with respect to characteristic time scales of our mixing problem. The results demonstrate that the micromixer is able to achieve high mixing degrees very rapidly. PMID:22712034

Bockelmann, Hendryk; Heuveline, Vincent; Barz, Dominik P. J.

2012-01-01

232

Effect of incorporation of uncertainty in PCB bioaccumulation factors on modeled receptor doses  

SciTech Connect

Bioaccumulation factors (BAFs) are regularly employed in ecological risk assessments to model contaminant transfer through ecological food chains. The authors compiled data on bioaccumulation of PCBs in plants, invertebrates, birds, and mammals from published literature and used these data to develop regression equations relating soil or food concentrations to bioaccumulation. They then used Latin Hypercube simulation techniques and simple food chain models to incorporate uncertainty in the BAF regressions into the derivation of exposure dose estimates for selected wildlife receptors. The authors present their preliminary results in this paper. Dose estimates ranged over several orders of magnitude for herbivorous, insectivorous, and carnivorous receptors. These results suggest incorporating the uncertainty in BAF values into food chain exposure models could provide risk assessors and risk managers with information on the probability of a given outcome that can be used in interpreting the potential risks at hazardous waste sites.

Welsh, C.; Duncan, J.; Purucker, S. [Oak Ridge National Lab., TN (United States). Center for Risk Management; Richardson, N. [ABB Environmental Services, Inc., Wakefield, MA (United States); Redfearn, A. [Automated Sciences Group, Inc., Oak Ridge, TN (United States)

1995-12-31

233

Low-disturbance manure incorporation effects on ammonia and nitrate loss.  

PubMed

Low-disturbance manure application methods can provide the benefits of manure incorporation, including reducing ammonia (NH3) emissions, in production systems where tillage is not possible. However, incorporation can exacerbate nitrate (NO3?) leaching. We sought to assess the trade-offs in NH3 and NO3? losses caused by alternative manure application methods. Dairy slurry (2006-2007) and liquid swine manure (2008-2009) were applied to no-till corn by (i) shallow (<10 cm) disk injection, (ii) surface banding with soil aeration, (iii) broadcasting, and (iv) broadcasting with tillage incorporation. Ammonia emissions were monitored for 72 h after application using ventilated chambers and passive diffusion samplers, and NO3? leaching to 80 cm was monitored with buried column lysimeters. The greatest NH3 emissions occurred with broadcasting (35-63 kg NH3-N ha?), and the lowest emissions were from unamended soil (<1 kg NH-N ha?¹). Injection decreased NH-N emissions by 91 to 99% compared with broadcasting and resulted in lower emissions than tillage incorporation 1 h after broadcasting. Ammonia-nitrogen emissions from banding manure with aeration were inconsistent between years, averaging 0 to 71% that of broadcasting. Annual NO3? leaching losses were small (<25 kg NO3-N ha?¹) and similar between treatments, except for the first winter when NO3? leaching was fivefold greater with injection. Because NO3? leaching with injection was substantially lower over subsequent seasons, we hypothesize that the elevated losses during the first winter were through preferential flow paths inadvertently created during lysimeter installation. Overall, shallow disk injection yielded the lowest NH3 emissions without consistently increasing NO3? leaching, whereas manure banding with soil aeration conserved inconsistent amounts of N. PMID:22565274

Dell, Curtis J; Kleinman, Peter J A; Schmidt, John P; Beegle, Douglas B

2012-01-01

234

Removal of chromium, nickel and cadmium from clays by in?situ electrokinetic remediation  

Microsoft Academic Search

This article presents the results of a research study that investigated the use of the in situ electrokinetic process for removing chromium, nickel, and cadmium from contaminated clays. For this study, electrokinetic experiments were conducted on two types of clays: kaolin, a commercial?grade soil consisting mainly of kaolinite clay mineral, and glacial till, a fíeld derived clay that possesses a

Krishna R. Reddy; Usha S. Parupudi

1997-01-01

235

A New Tangential Streaming Potential Setup for the Electrokinetic Characterization of Tubular Membranes  

Microsoft Academic Search

A new electrokinetic setup was developed for assessing the active layer ??potential of tubular membranes based on tangential streaming potential and electrical resistance measurements. Although the flow was not wholly laminar (because of the large hydraulic diameter of channels), the electrokinetics theory could be used to convert the streaming potential data into ??potentials because the electrical double layer lay within

P. Fievet; M. Sbaï; A. Szymczyk; C. Magnenet; C. Labbez; A. Vidonne

2004-01-01

236

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

E-print Network

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.

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

2007-05-08

237

High electrokinetic energy conversion efficiency in charged nanoporous nitrocellulose/sulfonated polystyrene membranes.  

PubMed

The synthesis, characterization, and electrokinetic energy conversion performance have been investigated experimentally in a charged polymeric membrane based on a blend of nitrocellulose and sulfonated polystyrene. The membrane is characterized by a moderate ion exchange capacity and a relatively porous structure with average pore diameter of 11 nm. With electrokinetic energy conversion, pressure can be converted directly into electric energy and vice versa. From the electrokinetic transport properties, a remarkably large intrinsic maximum efficiency of 46% is found. It is anticipated that the results are an experimental verification of theoretical models that predict high electrokinetic energy conversion efficiency in pores with high permselectivity and hydrodynamic slip flow. Furthermore, the result is a promising step for obtaining efficient low-cost electrokinetic generators and pumps for small or microscale applications. PMID:25555128

Haldrup, Sofie; Catalano, Jacopo; Hansen, Michael Ryan; Wagner, Manfred; Jensen, Grethe Vestergaard; Pedersen, Jan Skov; Bentien, Anders

2015-02-11

238

Tissue lead distribution and hematologic effects in American kestrels (Falco sparverius L.) fed biologically incorporated lead.  

PubMed

American kestrels were fed a diet containing 0.5, 120, 212, and 448 ppm (dry wt) biologically incorporated lead (Pb) for 60 days. The diet consisted of homogenized 4-wk-old cockerels raised on feed mixed with and without lead. No kestrels died and weights did not differ among treatment groups. The control group (0.5 ppm Pb) had the lowest mean concentration of lead and the high dietary group had the highest for the following tissues: Kidney, liver, femur, brain, and blood. Concentrations of lead were significantly correlated among tissues. There were no differences among treatment groups for packed cell volume, hemoglobin concentration, or erythrocyte count. PMID:6716559

Custer, T W; Franson, J C; Pattee, O H

1984-01-01

239

Tissue lead distribution and hematologic effects in american kestrels Falco sparverius fed biologically incorporated lead  

USGS Publications Warehouse

American kestrels were fed a diet containing 0.5, 120, 212 and 448 ppm (dry wt) biologically incorporated Pb for 60 days. The diet consisted of homogenized 4-wk-old cockerels raised on feed mixed with and without Pb. No kestrels died and weights did not differ among treatment groups. The control group (0.5 ppm Pb) had the lowest mean concentration of Pb and the high dietary group had the highest for the following tissues: kidney, liver, femur, brain and blood. Concentrations of Pb were significantly correlated among tissues. Treatment groups did not differ in packed cell volume, Hb concentration or erythrocyte count.

Custer, T.W.; Franson, J.C.; Pattee, O.H.

1984-01-01

240

Tissue lead distribution and hematologic effects in American kestrels (Falco sparverius) fed biologically incorporated lead  

USGS Publications Warehouse

American kestrels were fed a diet containing 0.5, 120, 212, and 448 ppm (dry wt) biologically incorporated lead (Pb) for 60 days. The diet consisted of homogenized 4-wk-old cockerels raised on feed mixed with and without lead. No kestrels died and weights did not differ among treatment groups. The control group (0.5 ppm Pb) had the lowest mean concentration of lead and the high dietary group had the highest for the following tissues: Kidney, liver, femur, brain, and blood. Concentrations of lead were significantly correlated among tissues. There were no differences among treatment groups for packed cell volume, hemoglobin concentration, or erythrocyte count.

Custer, T.W.; Franson, J.C.; Pattee, O.H.

1984-01-01

241

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

PubMed Central

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

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

2013-01-01

242

Functional properties and in vitro antioxidant and antibacterial effectiveness of pigskin gelatin films incorporated with hydrolysable chestnut tannin.  

PubMed

The impact of the incorporation of 10%?w/w of hydrolyzable chestnut tannin into pigskin gelatin (G) films plasticized with glycerol (Gly) on the physicochemical properties as well as the in vitro antioxidant and antibacterial effectiveness against food-borne pathogens such as Escherichia coli and Streptococcus aureus was investigated. A higher tendency to both redness (a*) and yellowness (b*) coloration characterized gelatin films incorporated with chestnut tannin. The reduced lightness (L) and transparency of gelatin-chestnut tannin films plasticized with 30%?w/w Gly might be associated with certain degree of phase separation which provoked the migration of the plasticizer to the film surface. The incorporation of chestnut tannin and glycerol affected the chemical structure of the resultant films due to the establishment of hydrogen interactions between components as revealed by Fourier transform infrared spectroscopy. These interactions reduced gelatin crystallinity and seemed to be involved in the substantial decrease of the water uptake of films with tannin, irrespective of the glycerol level. Such interactions had minor effect on tensile properties being similar to those of the control films (without chestnut tannin) at the same glycerol level. Films modified with 10%?w/w chestnut tannin showed significant (P?incorporated with 10%?w/w chestnut tannin against the selected bacteria evidenced by disk diffusion method probably resulted from the interactions within the film restricting the diffusion of the active agent into the agar medium. The more modest protective effect observed against a Gram-positive bacterium (S. aureus) was also discussed. PMID:24831641

Peña-Rodriguez, Cristina; Martucci, Josefa F; Neira, Laura M; Arbelaiz, Aitor; Eceiza, Arantxa; Ruseckaite, Roxana A

2015-04-01

243

A liposomal formulation able to incorporate a high content of Paclitaxel and exert promising anticancer effect.  

PubMed

A liposome formulation for paclitaxel was developed in this study. The liposomes, composed of naturally unsaturated and hydrogenated phosphatidylcholines, with significant phase transition temperature difference, were prepared and characterized. The liposomes exhibited a high content of paclitaxel, which was incorporated within the segregated microdomains coexisting on phospholipid bilayer of liposomes. As much as 15% paclitaxel to phospholipid molar ratio were attained without precipitates observed during preparation. In addition, the liposomes remained stable in liquid form at 4°C for at least 6 months. The special composition of liposomal membrane which could reduce paclitaxel aggregation could account for such a capacity and stability. The cytotoxicity of prepared paclitaxel liposomes on the colon cancer C-26 cell culture was comparable to Taxol. Acute toxicity test revealed that LD(50) for intravenous bolus injection in mice exceeded by 40?mg/kg. In antitumor efficacy study, the prepared liposomal paclitaxel demonstrated the increase in the efficacy against human cancer in animal model. Taken together, the novel formulated liposomes can incorporate high content of paclitaxel, remaining stable for long-term storage. These animal data also demonstrate that the liposomal paclitaxel is promising for further clinical use. PMID:21490755

Kan, Pei; Tsao, Chih-Wan; Wang, Ae-June; Su, Wu-Chou; Liang, Hsiang-Fa

2011-01-01

244

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

PubMed Central

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

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

2004-01-01

245

Effect of incorporation of pumpkin (Cucurbita moshchata) powder and guar gum on the rheological properties of wheat flour.  

PubMed

The present study was carried out to study the effect of incorporation of fibre rich pumpkin powder and guar gum on the farinographic characteristics of wheat flour. The flour and pumpkin powder were assessed for proximate composition, total dietary fibre, minerals and ?-carotene. Pumpkin powder contained appreciable amount of fibre, minerals and ?-carotene. The effects of incorporation of different levels of pumpkin powder and guar gum along with pumpkin powder on farinographic characteristics were studied. Dough development time, dough stability, time to break down and farinograph quality number increased whereas mixing tolerance index decreased with incorporation of pumpkin powder (> 5 %) and guar gum (1.0 and 1.5 %) along with pumpkin powder in the flour. Resistance to extension as well as extensibility of dough prepared increased significantly by adding pumpkin powder (5-15 %) whereas increase in resistance to extension only was noticed with inclusion of guar gum (0.5-1.5 %) to flour containing 5 % pumpkin powder. Results indicated that pumpkin can be processed to powder that can be utilized with guar gum for value addition. PMID:25328201

Kundu, Himani; Grewal, Raj Bala; Goyal, Ankit; Upadhyay, Neelam; Prakash, Saurabh

2014-10-01

246

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

SciTech Connect

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.

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

247

Electrokinetic electrode system for extraction of soil contaminants from unsaturated soils  

DOEpatents

An electrokinetic electrode assembly is described for use in extraction of soil contaminants from unsaturated soil in situ. The assembly includes a housing for retaining a liquid comprising an electrolyte solution, pure water, and soil water, the housing being in part of porous material capable of holding a vacuum. An electrode is mounted in the housing. The housing is provided with a vacuum orifice for effecting a vacuum within the housing selectively to control flow of soil water through the housing into the chamber and to control outflow of the liquid from the chamber. The assembly further includes conduit means for removing the liquid from the housing and returning the electrolyte solution to the housing, and a conduit for admitting pure water to the housing. An electrode system and method are also revealed for extraction of soil contaminants. The system and method utilize at least two electrode assemblies as described above. 5 figs.

Lindgren, E.R.; Mattson, E.D.

1995-07-25

248

Electrokinetic electrode system for extraction of soil contaminants from unsaturated soils  

DOEpatents

There is presented an electrokinetic electrode assembly for use in extraction of soil contaminants from unsaturated soil in situ. The assembly includes a housing for retaining a liquid comprising an electrolyte solution, pure water, and soil water, the housing being in part of porous material capable of holding a vacuum. An electrode is mounted in the housing. The housing is provided with a vacuum orifice for effecting a vacuum within the housing selectively to control flow of soil water through the housing into the chamber and to control outflow of the liquid from the chamber. The assembly further includes conduit means for removing the liquid from the housing and returning the electrolyte solution to the housing, and a conduit for admitting pure water to the housing. There is further presented an electrode system and method for extraction of soil contaminants, the system and method utilizing at least two electrode assemblies as described above.

Lindgren, Eric R. (Albuquerque, NM); Mattson, Earl D. (Albuquerque, NM)

1995-01-01

249

Effect of incorporating prebiotics in coating materials for the microencapsulation of Saccharomyces boulardii.  

PubMed

The objective of this study was to microencapsulate Saccharomyces boulardii using the emulsion technique. To microencapsulate the yeast, alginate sodium blended with inulin and mucilage from Opuntiaficus-indica was used as a coating material. The textural properties of the gels formed by the encapsulating materials and the in vitro viability of the yeast strain in the simulated conditions were studied. Textural profile analyses of the gels revealed differences (p < 0.05) in hardness because alginate produced stronger gels, whereas the incorporation of other hydrocolloids with alginate decreased gel strength and resulted in a more uniform, cohesive gel matrix. When alginate was blended with mucilage and inulin, encapsulated yeast presented higher counts and more viable cells, as compared to free yeast following 30 days of storage at 4 °C. Encapsulated and free yeast had 76.1% and 63.3%, respectively, of cell viability after 35 days of storage. PMID:22594787

Zamora-Vega, Rafael; Montañez-Soto, José Luis; Martínez-Flores, Héctor Eduardo; Flores-Magallón, Rebeca; Muñoz-Ruiz, Carlos Víctor; Venegas-González, José; Ariza Ortega, Teresita De Jesús

2012-12-01

250

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

PubMed

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

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

2013-01-01

251

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

SciTech Connect

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.

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

2011-12-31

252

Effect of In incorporated into SbTe on phase change characteristics resulting from changes in electronic structure  

NASA Astrophysics Data System (ADS)

The effects of the In content of InSbTe films with various stoichiometries (Sb2Te2.7, In0.5Sb2Te2.9, and In2.6Sb2Te2.9) on phase change characteristics were investigated. With increasing incorporation of In atoms into Sb2Te3, various crystalline phases, i.e., In2Te3, Sb, and In3SbTe2, were observed due to the bond energy between the constituent atoms, while only Sb2Te3 and the Sb2Te2 phases were observed in the case of Sb2Te2.7 and In0.5Sb2Te2.9 films. In addition, the shifts in binding energy of the Sb 3d and In 3d peaks in x-ray photoelectron spectra after the annealing treatment were directly related to the amount of incorporated In. The observed changes in electronic structure suggest that the changes in electrical conductivity and crystalline phase are directly related to the extent of In incorporation.

Jang, Moon Hyung; Park, Seung Jong; Lim, Dong Heok; Park, Sung Jin; Cho, Mann-Ho; Ko, Dae-Hong; Heo, M. Y.; Sohn, Hyun Chul; Kim, Sang-Ok

2010-02-01

253

Elastic, electrostatic and electrokinetic forces influencing membrane curvature.  

PubMed

Many cellular and intracellular processes critically depend on membrane shape, but the shape generating mechanisms are still to be fully understood. In this study we evaluate how electrostatic/electrokinetic forces contribute to membrane curvature. Membrane bilayer had finite thickness and was either elastically anisotropic or anisotropic overall, but isotropic per sections (heads and tails). The physics of the situation was evaluated using a coupled system of elastic and electrostatic/electrokinetic (Poisson-Nernst-Planck) equations. The fixed charges present only on the upper membrane surface lead to the accumulation of counter-ions and depletion of co-ions that decay spatially very rapidly (Debye length<1nm), as does the potential and electric field. Spatially uneven electric field and the permittivity mismatch also induce charges at the membrane-solution interface, which are not fixed but influence the electrostatics nevertheless. Membrane bends due to - Coulomb force (caused by fixed membrane charges in the electric field) and the dielectric force (due to the non-uniform electric field and the permittivity mismatch between the membrane and the solution). Both act as membrane surface forces, and both depend supra-linearly on the fixed charge density. Regardless of sign of the fixed charges, the membrane bends toward the charged (upper) surface owing to the action of the Coulomb force, but this is opposed by the smaller dielectric force. The spontaneous membrane curvature becomes very pronounced at high fixed charge densities, leading to very small spontaneous radii (<50nm). In conclusion the electrostatic/electrokinetic forces contribute significantly to the membrane curvature. PMID:22051020

Tajparast, M; Glavinovi?, M I

2012-03-01

254

Effect of Zn incorporation into CuInS2 solar cell absorbers on microstructural and electrical properties  

NASA Astrophysics Data System (ADS)

Zn incorporation into CuInS2 absorbers is found to increase the open-circuit voltage but decrease the short-circuit current of the corresponding thin-film solar cells. In this article, we study the effect of Zn incorporation into CuInS2 absorbers with a focus on the mechanisms leading to the measured changes in the electrical properties of the solar cells. Solar cells with varying Zn concentrations in their absorbers are characterized via the application of transmission electron microscopy, quantum efficiency, and current-voltage measurements, as well as admittance, x-ray photoelectron and photoluminescence spectroscopy. A Zn accumulation on the absorber side of the CuInS2-CdS interface and a higher structural defect density within the absorber are found after Zn incorporation. Capacitance, quantum efficiency, and current-voltage measurements in combination with device simulations suggest that Zn incorporation induces or enhances a shallow donor at the CuInS2-CdS interface. The interface defect pins the Fermi level close to the CdS conduction band, leading to an inversion at the heterointerface and thus reducing the recombination at interface defects and increasing the open-circuit voltage. A shallow bulk acceptor about 0.15 eV above the valence band edge is observed to increase with increasing Zn concentration in the CuInS2 absorbers and is responsible for a gradual decrease in the short-circuit current and the gain in the open-circuit voltage as the Zn concentration increases.

Schmidt, S. S.; Abou-Ras, D.; Unold, T.; Eisenbarth, T.; Wilhelm, H.; Grimm, A.; Klaer, J.; Schock, H.-W.

2011-09-01

255

Effect of formulation factors on incorporation of the hydrophilic peptide dalargin into PLGA and mPEG-PLGA nanoparticles.  

PubMed

The objective of this study was to examine formulation factors that influence the incorporation of the hydrophilic peptide dalargin into poly(D, L-lactic-co-glycolic acid) (PLGA) and methoxy-polyethylene glycol (mPEG)-PLGA nanoparticles. In particular, the effect of ionic additives and nanoparticle method of preparation on the incorporation of dalargin and resultant nanoparticle properties was investigated. Biodegradable nanoparticles were prepared from mPEG-PLGA and PLGA by both solvent evaporation and solvent diffusion methods with inclusion of ionic additives of dextran sulphate (DS), sulfobutyl ether-beta-cyclodextrin (SB-CD), or sodium dodecyl sulfate (SDS). The resultant nanoparticles were analyzed for their mean particle size and size distribution, zeta-potential, peptide loading, yield, and morphology. The inclusion of ionic additives in the nanoparticle formulation significantly influenced dalargin entrapment efficiency (EE). For example, with the PLGA/SDS formulation EE increased from 13.3% to 91.2% and from 4.1% to 68.6% with the solvent diffusion and evaporation methods, respectively. The inclusion of ionic surfactant SDS has also lead to the formation of smaller size of nanoparticles. Isothermal titration microcalorimetry revealed a strong interaction between dalargin and DS, medium level interaction with SDS, and weak interaction with SB-CD. The results of this study suggest that a strong ionic interaction between peptides and additives may lead to enhanced peptide incorporation but also increased particle size. Intermediate ionic interaction, especially when it is associated with the formation of reversed micelles in a hydrophobic polymer solution, could be used to enhance the incorporation of hydrophilic peptides in PLGA and mPEG-PLGA nanoparticles. PMID:18459172

Chen, Y; Wang, F; Benson, H A E

2008-01-01

256

Non-equilibrium electrokinetic micromixer with 3D nanochannel networks.  

PubMed

We report an active micromixer which utilizes vortex generation due to non-equilibrium electrokinetics near the interface between a microchannnel and a nanochannel networks membrane (NCNM), constructed from geometrically controlled in situ self-assembled nanoparticles. A large interfacing area where it is possible to generate vortices can be realized, because nano-interstices between the assembled nanoparticles are intrinsically collective three-dimensional nanochannel networks, which may be compared to typical silicon-based 2D nanochannels. The proposed mixer shows a 2-fold shorter mixing time (~0.78 ms) and a 34-fold shorter mixing length (~7.86 ?m) compared to conventional 2D nanochannels. PMID:25710479

Choi, Eunpyo; Kwon, Kilsung; Lee, Seung Jun; Kim, Daejoong; Park, Jungyul

2015-03-31

257

Electrokinetic instability near charge-selective hydrophobic surfaces  

NASA Astrophysics Data System (ADS)

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.

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

2014-07-01

258

ELECTROKINETIC DENSIFICATION OF COAL FINES IN WASTE PONDS  

SciTech Connect

The objective of this research was to demonstrate that electrokinetics can be used to remove colloidal coal and mineral particles from coal-washing ponds and lakes without the addition of chemical additives such as salts and polymeric flocculants. The specific objectives were: Design and develop a scaleable electrophoresis apparatus to clarify suspensions of colloidal coal and clay particles; Demonstrate the separation process using polluted waste water from the coal-washing facilities at the coal-fired power plants in Centralia, WA; Develop a mathematical model of the process to predict the rate of clarification and the suspension electrical properties needed for scale up.

E. James Davis

1999-12-18

259

Incorporating Effects of Process, Voltage, and Temperature Variation in BTI Model for Circuit  

E-print Network

Temperature Instability (BTI) is a major reliability issue in Nano-scale CMOS circuits. BTI effect results) dependence of BTI effect, and the significant amount of PVT variations in Nano-scale CMOS, we propose. Keywords- Aging effects; Nano-scale CMOS; Process variations; Voltage variations; Temperature variations I

Mahmoodi, Hamid

260

Thermodynamic and hydration effects for the incorporation of a cationic 3-aminopropyl chain into DNA.  

PubMed

The introduction of cationic 5-(omega-aminoalkyl)-2'-deoxypyrimidines into duplex DNA has been shown to induce DNA bending. In order to understand the energetic and hydration contributions for the incorporation of a cationic side chain in DNA a combination of spectroscopy, calorimetry and density techniques were used. Specifically, the temperature unfolding and isothermal formation was studied for a pair of duplexes with sequence d(CGTAGUCG TGC)/d(GCACGACTACG), where U represents 2'-deoxyuridine ('control') or 5-(3-aminopropyl)-2'-deoxyuridine ('modified'). Continuous variation experiments confirmed 1:1 stoichiometries for each duplex and the circular dichroism spectra show that both duplexes adopted the B conformation. UV and differential scanning calorimetry melting experiments reveal that each duplex unfolds in two-state transitions. In low salt buffer, the 'modified' duplex is more stable and unfolds with a lower endothermic heat and lower release of counterion and water. This electrostatic stabilization is entropy driven and disappears at higher salt concentrations. Complete thermodynamic profiles at 15 degrees C show that the favorable formation of each duplex results from the compensation of a favorable exothermic heat with an unfavorable entropy contribution. However, the isothermal profiles yielded a differential enthalpy of 8.8 kcal/mol, which is 4.3 kcal/mol higher than the differential enthalpy observed in the unfolding profiles. This indicates that the presence of the aminopropyl chain induces an increase in base stacking interactions in the modified single strand and a decrease in base stacking interactions in the modified duplex. Furthermore, the formation of the 'control' duplex releases water while the 'modified' duplex takes up water. Relative to the control duplex, formation of the modified duplex at 15 degrees C yielded a marginal differential DeltaG degrees term, positive DeltaDeltaH(ITC)-Delta(TDeltaS) compensation, negative DeltaDeltaV and a net release of counterions. The opposite signs of the differential enthalpy-entropy compensation and differential volume change terms show a net uptake of structural water around polar and non-polar groups. This indicates that incorporation of the aminopropyl chain induces a higher exposure of aromatic bases to the solvent, which may be consistent with a small and local bend in the 'modified' duplex. PMID:12136099

Soto, Ana Maria; Kankia, Besik I; Dande, Prasad; Gold, Barry; Marky, Luis A

2002-07-15

261

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

NASA Technical Reports Server (NTRS)

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.

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

2010-01-01

262

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

SciTech Connect

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.

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

263

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

PubMed Central

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

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

2014-01-01

264

Large sensitivity enhancement in semiconducting organic field effect transistor sensors through incorporation of ultra-fine platinum nanoparticles  

SciTech Connect

We report remarkable improvement in sensitivity of pentacene-based field effect transistor devices towards trace nitro-aromatic explosive vapors through the incorporation of high density, sub-2?nm platinum nanoparticles (NPs) within these structures. Exploiting the unique electronic properties of these NPs, we have demonstrated a detection limit of 56.6 parts per billion of 2,4-dinitrotoluene (DNT) vapor while control samples without any embedded NPs showed no observable sensitivity to DNT vapor. We attribute this remarkable enhancement in sensitivity to the ability of these NPs to function as discrete nodes, participating in the charge transfer with adsorbed nitro-aromatic molecules.

Zheng, Haisheng; Ramalingam, Balavinayagam; Korampally, Venumadhav; Gangopadhyay, Shubhra, E-mail: gangopadhyays@missouri.edu [Department of Electrical and Computer Engineering, University of Missouri, Columbia, Missouri 65201 (United States)] [Department of Electrical and Computer Engineering, University of Missouri, Columbia, Missouri 65201 (United States)

2013-11-04

265

Simple gain form of 1.5 µm multimode laser diode incorporating band filling and intrinsic gain saturation effects  

NASA Astrophysics Data System (ADS)

The gain form of a 1.5 µm multimode laser diode was derived by phenomenologically adding an intrinsic gain saturation term to the linearized gain form described in our previous report. Although the proposed gain form was simple, it almost perfectly matched the complex laser diode gain in a direct transition model implicitly incorporating both band filling and intrinsic gain saturation effects. Using laser diode rate equations including the proposed gain form, the characteristic power spectrum of a gain-switched pulse from a 1.5 µm multimode laser diode was successfully simulated.

Wada, Kenji; Matsuyama, Tetsuya; Horinaka, Hiromichi

2015-03-01

266

Characterization of chitosan nanofiber fabric by electrospray deposition: electrokinetic and adsorption behavior.  

PubMed

Cationic biopolymer nanofiber fabrics were prepared from a chitosan/poly(ethylene oxide) blend solution by electrospray deposition. Their electrokinetic properties and DNA adsorption behavior were analyzed as a function of pH. The zeta potential was determined from streaming potential/streaming current measurements. The adsorption of DNA onto the fabrics was investigated by spectrophotoscopy. The adsorption behavior of DNA correlated well with the electrokinetic properties of the fabrics. This revealed that the electrokinetic approach was a useful option for characterization of novel nanofiber assemblies made by the electrostatic spray process. In addition, these results provided fundamental information about chitosan nanofiber fabrics for both biomedical and analytical applications. PMID:17359992

Matsumoto, Hidetoshi; Yako, Hiroshi; Minagawa, Mie; Tanioka, Akihiko

2007-06-15

267

Effect of silver nanoparticles incorporated with samarium-doped magnesium tellurite glasses  

NASA Astrophysics Data System (ADS)

Silver nanoparticles (Ag NPs) are incorporated in samarium doped tellurite glass of a composition (89-x)TeO2-10MgO-1Sm2O3-xAgCl, where 0.0?x?0.6 mol%, by a melt quenching technique. It is found that all the glasses are amorphous in nature, and the existence of Ag NPs with an average size of 16.94 nm is confirmed by Transmission Electron Microscopy. Meanwhile, their physical properties such as glass density, molar volume and ionic packing density are computed utilizing the normal method. The density and ionic packing density are observed to decrease with increasing Ag NPs, but increase when the Ag NPs are beyond 0.2 mol%. On the other hand, the molar volume behaves exactly opposite to the increase in Ag NPs content. It decreases when the Ag NPs content value is more than 0.2 mol%. The optical energy band gap and Urbach energy are evaluated from the absorption spectra in the range of 200-900 nm at room temperature. It is also observed that the direct and indirect optical energy band gaps reduce with Ag NPs content, but enhance when the Ag NPs are beyond 0.2 mol%. Meanwhile, the Urbach energy is found to increase as the Ag NPs content is increased but decreases when Ag NPs is 0.2 mol%. The refractive index is deduced from indirect optical energy band gap. Meanwhile, molar refraction and electronic polarizability have been calculated from the Lorentz-Lorentz relation. Refractive index and electronic polarizability are also observed to raise with Ag NPs content, but drop off when Ag NPs content is more than 0.2 mol%. In this paper, all properties are discussed with respect to the Ag NPs concentration.

Yusoff, N. M.; Sahar, M. R.

2015-01-01

268

The effect of nitrogen incorporation on the bonding structure of hydrogenated carbon nitride films  

SciTech Connect

This work describes the composition and bonding structure of hydrogenated carbon nitride (a-CN{sub x}:H) films synthesized by electron cyclotron resonance chemical vapor deposition using as precursor gases argon, methane, and nitrogen. The composition of the films was derived from Rutherford backscattering and elastic recoil detection analysis and the bonding structure was examined by infrared (IR) spectroscopy and x-ray absorption near edge spectroscopy (XANES). By varying the nitrogen to methane ratio in the applied gas mixture, polymeric a-CN{sub x}:H films with N/C contents varying from 0.06 to 0.49 were obtained. Remarkably, the H content of the films ({approx}40 at. %) was rather unaffected by the nitrogenation process. The different bonding states as detected in the measured XANES C(1s) and N(1s) spectra have been correlated with those of a large number of reference samples. The XANES and IR spectroscopy results indicate that N atoms are efficiently incorporated into the amorphous carbon network and can be found in different bonding environments, such as pyridinelike, graphitelike, nitrilelike, and amino groups. The nitrogenation of the films results in the formation of N-H bonding environments at the cost of C-H structures. Also, the insertion of N induces a higher fraction of double bonds in the structure at the expense of the linear polymerlike chains, hence resulting in a more cross-linked solid. The formation of double bonds takes place through complex C=N structures and not by formation of graphitic aromatic rings. Also, the mechanical and tribological properties (hardness, friction, and wear) of the films have been studied as a function of the nitrogen content. Despite the major modifications in the bonding structure with nitrogen uptake, no significant changes in these properties are observed.

Camero, M.; Buijnsters, J. G.; Gomez-Aleixandre, C.; Gago, R.; Caretti, I.; Jimenez, I. [Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), C/ Sor Juana Ines de la Cruz 3, Cantoblanco, 28049 Madrid (Spain); Centro de Micro-Analisis de Materiales (CMAM) and Departamento de Fisica Aplicada, Universidad Autonoma de Madrid, C/ Faraday 3, Cantoblanco, 28049 Madrid (Spain); Department of Physics, University of Antwerp, Campus Drie Eiken, Universiteitsplein 1, 2610 Wilrijk (Belgium); Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), C/ Sor Juana Ines de la Cruz 3, Cantoblanco, 28049 Madrid (Spain); Instituto de Ciencia y Tecnologia de Polimeros (ICTP-CSIC), Juan de la Cierva 3, 28006 Madrid (Spain)

2007-03-15

269

Development of improved Li-ion battery model incorporating thermal and rate factor effects  

Microsoft Academic Search

This paper presents development of an improved electrical circuit based Li-ion battery model using AMESim. This model considers charge extraction due to current, battery capacity, and effect of internal resistance and extends the thermal aspects which represent temperature rise in the core and crust. The thermal aspects that characterize the temperature rise in core and crust and its effects on

Sachin Bhide; Taehyun Shim

2009-01-01

270

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

PubMed

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

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

2015-06-15

271

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

NASA Astrophysics Data System (ADS)

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.

Jan, Der-E.

272

Electrokinetic particle separation in a single-spiral microchannel  

NASA Astrophysics Data System (ADS)

The efficient separation of discrete particle species is a topic of interest in numerous research fields for its practical application to problems encountered in both academia and industry. We have recently developed an electrokinetic technique that exploits the curvature-induced dielectrophoresis (C-iDEP) to continuously sort particles by inherent properties in asymmetric double-spiral microchannels. Herein we demonstrate that a single-spiral microchannel is also sufficient for a continuous-flow sheathless electrokinetic particle separation. This method relies on C-iDEP to focus particles to a tight stream and the wall-induced electric lift to manipulate the aligned particles to size-dependent equilibrium positions, both of which happen simultaneously inside the spiral. A theoretical model is developed to understand this size-based separation, which has been implemented for both a binary mixture and a ternary mixture of colloidal particles. The obtained analytical formulae predict with a close agreement both the experimentally measured particle center–wall distance and the necessary electric field for a complete particle focusing in the spiral.

DuBose, John; Zhu, Junjie; Patel, Saurin; Lu, Xinyu; Tupper, Nathaniel; Stonaker, John M.; Xuan, Xiangchun

2014-11-01

273

Feasibility of electrokinetic oxygen supply for soil bioremediation purposes.  

PubMed

This paper studies the possibility of providing oxygen to a soil by an electrokinetic technique, so that the method could be used in future aerobic polluted soil bioremediation treatments. The oxygen was generated from the anodic reaction of water electrolysis and transported to the soil in a laboratory-scale electrokinetic cell. Two variables were tested: the soil texture and the voltage gradient. The technique was tested in two artificial soils (clay and sand) and later in a real silty soil, and three voltage gradients were used: 0.0 (control), 0.5, and 1.0 V cm(-1). It was observed that these two variables strongly influenced the results. Oxygen transport into the soil was only available in the silty and sandy soils by oxygen diffusion, obtaining high dissolved oxygen concentrations, between 4 and 9 mg L(-1), useful for possible aerobic biodegradation processes, while transport was not possible in fine-grained soils such as clay. Electro-osmotic flow did not contribute to the transport of oxygen, and an increase in voltage gradients produced higher oxygen transfer rates. However, only a minimum fraction of the electrolytically generated oxygen was efficiently used, and the maximum oxygen transport rate observed, approximately 1.4 mgO2 L(-1)d(-1), was rather low, so this technique could be only tested in slow in-situ biostimulation processes for organics removal from polluted soils. PMID:25173714

Mena Ramírez, E; Villaseñor Camacho, J; Rodrigo Rodrigo, M A; Cañizares Cañizares, P

2014-12-01

274

Electrokinetics Enhanced Delivery of Nano-scale Zero Valent Iron  

NASA Astrophysics Data System (ADS)

Nano-scale zero valent iron (NZVI) has shown promising results for remediation of a wide range of chlorinated hydrocarbons in the subsurface. Although rapid aggregation and subsequent sedimentation limit bare NZVI migration in subsurface systems, surface modifications have improved the colloidal stability of NZVI, enhancing NZVI migration through porous media in lab-scale experiments. However, delivery of NZVI through low permeability soil is still an unresolved challenge. Electrokinetics (EK) has been used extensively in low permeability porous media for the remediation of a variety of hazardous wastes and in particular heavy metals. Since NZVI has a net negative surface charge electrokinetics has been proposed to enhance NZVI transport in the subsurface. However, increased dissolved oxygen and lower pH, due to electrolysis of water at the anode, oxidizes Fe0 particles to Fe2+/Fe3+ and thus affects the remediation potential. This study focuses on minimization of NZVI oxidation and quantification of NZVI migration enhancement due to the EK application. Application of 50 and 100 mA currents delivered 6.0 and 4.8 times more NZVI through coarse sand, respectively, when compared to no EK application. This ratio increased to 21 and 31 at 50 and 100 mA currents when finer sand was used. In addition, a numerical model based on traditional colloidal filtration theory (CFT) fit the experimental results well.

Chowdhury, A. I.; O'Carroll, D. M.; Xu, Y.; Sleep, B. E.

2010-12-01

275

Electrokinetic removal of uranium from contaminated, unsaturated soils  

SciTech Connect

Electrokinetic remediation of uranium-contaminated soil was studied in a series of laboratory-scale experiments in test cells with identical geometry using quartz sand at approximately 10 percent moisture content. Uranium, when present in the soil system as an anionic complex, could be migrated through unsaturated soil using electrokinetics. The distance that the uranium migrated in the test cell was dependent upon the initial molar ratio of citrate to uranium used. Over 50 percent of the uranium was recovered from the test cells using the citrate and carbonate complexing agents over of period of 15 days. Soil analyses showed that the uranium remaining in the test cells had been mobilized and ultimately would have been extracted. Uranium extraction exceeded 90 percent in an experiment that was operated for 37 days. Over 70 percent of the uranium was removed from a Hanford waste sample over a 55 day operating period. Citrate and carbonate ligand utilization ratios required for removing 50 percent of the uranium from the uranium-contaminated sand systems were approximately 230 moles ligand per mole uranium and 1320 moles ligand per mole uranium for the waste. Modifying the operating conditions to increasing the residence time of the complexants is expected to improved the utilization efficiency of the complexing agent.

Booher, W.F. [IT Corp., Albuquerque, NM (United States); Lindgren, E.R.; Brady, P.V. [Sandia National Laboratories, Albuquerque, NM (United States)

1997-01-01

276

Evaluation of electrokinetic removal of heavy metals from sewage sludge.  

PubMed

The presence of heavy metals is one of the main obstacles for agricultural use of million tonnes of dewatered sewage sludge produced in wastewater treatment plants. Electrokinetic (EK) treatment can be applied to remove heavy metals from sludge. The aim of this study was to increase the efficiency of electrokinetic removal of heavy metals from dewatered sewage sludge. EK experiments were carried out with and without pH adjustment in cathode chamber of acidified sewage sludge. The selective sequential extraction (SSE) was used to determine the fractionation of heavy metals in sewage sludge. The mobility of heavy metals in sludge significantly increased after its acidification at pH 2.7 and followed the order: Ni, Zn, Cu, As, Cr, Pb. Removal efficiencies of heavy metals in the experiment with acidified sewage sludge and pH adjustment at cathode chamber at 2.0 were: 95% for Zn, 96% for Cu, 90% for Ni, 68% for Cr, 31% for As and 19% for Pb. The concentrations of Zn, Cu, Ni, Cr and Pb after EK treatment were below the United States Environmental Protection Agency limits for biosolids applied to agricultural land, forest, public contact sites or reclamation sites. PMID:15994006

Wang, Jing-Yuan; Zhang, Di-Song; Stabnikova, Olena; Tay, Joo-Hwa

2005-09-30

277

Numerical simulation of electrokinetic potentials associated with subsurface fluid flow  

NASA Astrophysics Data System (ADS)

A postprocessor has been developed to calculate space/time distributions of electrokinetic potentials resulting from histories of underground conditions (pressure, temperature, vapor saturation, concentrations of dissolved species, flow rate, etc.) computed by unsteady multidimensional geothermal reservoir simulations. Electrokinetic coupling coefficients are computed by the postprocessor using formulations based on experimental work reported by Ishido and Mizutani [1981]. The postprocessor was applied to both numerical modeling of natural self-potential (SP) anomalies in geothermal fields and production-induced SP changes. The essential features of the SP anomalies and SP changes which have actually been observed in real geothermal fields are reproduced reasonably well in these calculations for both single-phase (liquid) and two-phase (vapor/liquid) geothermal reservoirs. The postprocessor was also applied to predicting the magnitude of electrical earthquake precursory signals caused by dilatant strains taking place within a narrow vertical fault zone. If the rate of porosity increase is high enough to induce substantial pore pressure decrease, two-phase flow develops in the fault zone and produces observable signals at the ground surface if a high conductivity channel connects the near-surface region and the deep fault zone.

Ishido, Tsuneo; Pritchett, John W.

1999-07-01

278

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

E-print Network

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 ...

Patterson. Alex A. (Alex Andrew)

2013-01-01

279

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 ...

280

46 CFR 162.017-1 - Preemptive effect; incorporation by reference.  

Code of Federal Regulations, 2012 CFR

...ENGINEERING EQUIPMENT General Provisions; Valves, Pressure-Vacuum Relief, for Tank Vessels § 162.017-1 Preemptive effect... (1) ISO 15364, Ships and Marine Technology—Pressure/Vacuum Valves for Cargo Tanks, First Edition (Sep. 1,...

2012-10-01

281

Effects of Incorporating Nanosized Calcium Phosphate Particles on Properties of Whisker-Reinforced Dental Composites  

PubMed Central

Clinical data indicate that secondary caries and restoration fracture are the most common problems facing tooth restorations. Our ultimate goal was to develop mechanically-strong and caries-inhibiting dental composites. The specific goal of this pilot study was to understand the relationships between composite properties and the ratio of reinforcement filler/releasing filler. Nanoparticles of monocalcium phosphate monohydrate (MCPM) were synthesized and incorporated into a dental resin for the first time. Silicon carbide whiskers were fused with silica nanoparticles and mixed with the MCPM particles at MCPM/whisker mass ratios of 1:0, 2:1, 1:1, 1:2, and 0:1. The composites were immersed for 1–56 days to measure Ca and PO4 release. When the MCPM/whisker ratio was changed from 0:1 to 1:2, the composite flexural strength (mean ± SD; n = 5) decreased from 174 ± 26 MPa to 138 ± 9 MPa (p < 0.05). A commercial nonreleasing composite had a strength of 112 ± 14 MPa. When the MCPM/whisker ratio was changed from 1:2 to 1:1, the Ca concentration at 56 days increased from 0.77 ± 0.04 mmol/L to 1.74 ± 0.06 mmol/L (p < 0.05). The corresponding PO4 concentration increased from 3.88 ± 0.21 mmol/L to 9.95 ± 0.69 mmol/L (p < 0.05). Relationships were established between the amount of release and the MCPM volume fraction vMCPM in the resin: [Ca]= 42.9 vMCPM2.7, and [PO4] = 48.7 vMCPM1.4. In summary, the method of combining nanosized releasing fillers with reinforcing fillers yielded Ca- and PO4-releasing composites with mechanical properties matching or exceeding a commercial stress-bearing, nonreleasing composite. This method may be applicable to the use of other Ca–PO4 fillers in developing composites with high stress-bearing and caries-preventing capabilities, a combination not yet available in any dental materials. PMID:16924611

Xu, Hockin H. K.; Sun, Limin; Weir, Mike D.; Takagi, Shozo; Chow, Laurence C.; Hockey, Bernard

2009-01-01

282

Sensitive enantioanalysis of ?-blockers via field-amplified sample injection combined with water removal in microemulsion electrokinetic chromatography.  

PubMed

In this study, an on-line sample preconcentration technique, field-amplified sample injection combined with water removal by electroosmotic flow (EOF) pump, was applied to realize a highly sensitive chiral analysis of ?-blocker enantiomers by MEEKC. The introduction of a water plug in capillary before the electrokinetic injection provided the effective preconcentration of chiral compounds. And then the water was moving out of the column from the injection end under the effect of the EOF, which avoided dilution of the stacked ?-blocker enantiomers concentration suffering from the presence of water in separation buffer. Moreover, the addition of H3 PO4 and methanol in the sample solution greatly improved the enhancement efficiency further. Under optimized conditions, more than 2700-fold enhancement in sensitivity was obtained for each enantiomer of bupranolol (BU), alprenolol (AL), and propranolol (PRO) via electrokinetic injection. LODs were 0.10, 0.10, 0.12, 0.11, 0.02, and 0.02 ng/mL for S-BU, R-BU, S-AL, R-AL, S-PRO, and R-PRO, respectively. Eventually, the proposed method was successfully applied to the determination of BU, AL, and PRO in serum samples with good recoveries ranging from 93.4 to 98.2%. PMID:24798241

Ma, Yanhua; Zhang, Huige; Rahman, Zia Ur; Wang, Weifeng; Li, Xi; Chen, Hongli; Chen, Xingguo

2014-10-01

283

A Measure of the Effectiveness of Incorporating 3D Human Anatomy into an Online Undergraduate Laboratory  

ERIC Educational Resources Information Center

Results of a study designed to determine the effectiveness of implementing three-dimensional (3D) stereo images of a human skull in an undergraduate human anatomy online laboratory were gathered and analysed. Mental model theory and its applications to 3D relationships are discussed along with the research results. Quantitative results on 62 pairs…

Hilbelink, Amy J.

2009-01-01

284

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...

285

Trauma management incorporating focused assessment with computed tomography in trauma (FACTT) - potential effect on survival  

Microsoft Academic Search

BACKGROUND: Immediate recognition of life-threatening conditions and injuries is the key to trauma management. To date, the impact of focused assessment with computed tomography in trauma (FACTT) has not been formally assessed. We aimed to find out whether the concept of using FACTT during primary trauma survey has a negative or positive effect on survival. METHODS: In a retrospective, multicentre

Karl-Georg Kanz; April O Paul; Rolf Lefering; Michael V Kay; Uwe Kreimeier; Ulrich Linsenmaier; Wolf Mutschler; Stefan Huber-Wagner

2010-01-01

286

Promotion and computation of inhibitory effect on tyrosinase activity of herbal cream by incorporating indigenous medicinal plants.  

PubMed

Herbal cream imparts a chief role in regulating melanin production of skin. The phytoconstituents present in herbal cream impact biological functions of skin and contribute nutrients required for the healthy skin. In the present study, it was envisaged to prepare three batches of herbal cream (HC1, HC2 and HC3) containing ethanol extracts of Emblica officinalis (fruits), Daucus carota (root), Mangifera indica (leaves), Mentha arvensis (leaves), Terminalia arjuna (bark) and Cucumis sativus (fruits) and investigated the prepared cream for inhibitory effect on tyrosinase activity. The herbal cream was formulated by incorporating different ratio of extracts, by using cream base. Each formulation HC1, HC2 and HC3 were segregated into three different formulations (HC1.1, HC1.2, HC1.3, HC2.1, HC2.2, HC2.3, HC3.1, HC3.2 and HC3.3) by incorporating increasing ratio of extract in formulation. The HC3.2 cream produces highest tyrosinase inhibitory effect 65.23 +/- 0.07%, while the HC2.1 exhibited minimum tyrosinase inhibitory effect 26.19 +/- 0.08% compared to other prepared cream. Comparison of the inhibitory activity of the formulations demonstrated that the rank order was HC3.2 > HC3.3 > HC1.2 > HC1.3 > HC3.1 > HC1.1 > HC2.3 > HC2.2 > HC2.1. It has been observed from the result that the formulations of antityrosinase activity were not concentrate dependent. This finding suggests that decrease in antityrosinase activity of HC1 and HC3 might be considering that the incompatibility of the higher extract content with the base of cream. The HC3 produce the maximum inhibitory effects on tyrosinase activity might be due to higher level of polyphenol and flavonoids present in extracts. PMID:24783796

Sahu, Ram Kumar; Roy, Amit; Dwivedi, Jaya; Jha, Arvind Kumar

2014-01-01

287

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

NASA Astrophysics Data System (ADS)

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.

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

2015-01-01

288

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

E-print Network

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) ...

Cheow, Lih Feng

289

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

E-print Network

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 ...

Cheow, Lih Feng

290

MICELLAR ELECTROKINETIC CHROMATOGRAPHY: A NEW TOOL FOR FIELD SCREENING OF SEMIVOLATILES  

EPA Science Inventory

Capillary electrophoresis (CE) and the related techniques of micellar electrokinetic chromatography (MEKC) are relatively new to environmental analysis. E is better known in the biomedical and pharmaceutical fields where it is employed for protein and drug separations, respective...

291

Space-time resolved electrokinetics in cylindrical and semi-cylindrical microchannels  

E-print Network

It is shown show how to employ Bessel-Fourier series in order to obtain a complete space-time resolved description of electrokinetic phenomena in cylindrical and semi-cylindrical microfluidic channels.

Michele Campisi

2007-05-03

292

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

E-print Network

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 ...

Bazant, Martin Z.

293

SANDIA NATIONAL LABORATORIES IN SITU ELECTROKINETIC EXTRACTION TECHNOLOGY; INNOVATIVE TECHNOLOGY EVALUATION REPORT  

EPA Science Inventory

As a part of the Superfund Innovative Technology Evaluation (SITE) Program, the U.S. Environmental Protection Agency evaluated the In-Situ Electrokinetic Extraction (ISEE) system at Sandia National Laboratories, Albuquerque, New Mexico. The SITE demonstration results show ...

294

Effect of combined treatment with the epirubicin-incorporating micelles (NC-6300) and 1,2-diaminocyclohexane platinum (II)-incorporating micelles (NC-4016) on a human gastric cancer model.  

PubMed

Anticancer agent-incorporating polymeric micelles accumulate effectively in tumors via the enhanced permeability and retention effect to exert potent antitumor effects. However, combined use of such micelles has not been elucidated. We compared the effect of combining the epirubicin-incorporating micelle NC-6300 and 1,2-diaminocyclohexane platinum (II) (oxaliplatin parent complex)-incorporating micelle NC-4016 (NCs) with that of epirubicin and oxaliplatin (E/O) in 44As3Luc cells using the combination index method. The in vivo antitumor activities of NCs and E/O were evaluated in mice bearing 44As3Luc xenografts. Pharmacokinetic analysis was performed by high-performance liquid chromatography and mass spectrometry. Cardiotoxicity of NC-6300 and epirubicin was assessed by echocardiography. Neurotoxicity of NC-4016 and oxaliplatin was evaluated by examining the paw withdrawal response to noxious mechanical stimuli. NCs showed a highly synergistic activity equivalent to E/O. In vivo, NCs exhibited higher antitumor activity in the subcutaneous tumor model and longer overall survival in the orthotopic tumor model than E/O (p?

Yamamoto, Yoshiyuki; Hyodo, Ichinosuke; Takigahira, Misato; Koga, Yoshikatsu; Yasunaga, Masahiro; Harada, Mitsunori; Hayashi, Tatsuyuki; Kato, Yasuki; Matsumura, Yasuhiro

2014-07-01

295

Development of a set of equations for incorporating disk flexibility effects in rotordynamical analyses  

NASA Technical Reports Server (NTRS)

Rotordynamical equations that account for disk flexibility are developed. These equations employ free-free rotor modes to model the rotor system. Only transverse vibrations of the disks are considered, with the shaft/disk system considered to be torsionally rigid. Second order elastic foreshortening effects that couple with the rotor speed to produce first order terms in the equations of motion are included. The approach developed in this study is readily adaptable for usage in many of the codes that are current used in rotordynamical simulations. The equations are similar to those used in standard rigid disk analyses but with additional terms that include the effects of disk flexibility. An example case is presented to demonstrate the use of the equations and to show the influence of disk flexibility on the rotordynamical behavior of a sample system.

Flowers, George T.; Ryan, Stephen G.

1991-01-01

296

Methods for incorporating the effects of LWR coolant environments in pressure vessel and piping fatigue evaluations  

Microsoft Academic Search

This paper summarizes the work performed at Argonne National Laboratory on the fatigue of piping and pressure vessel steels in the coolant environments of light water reactors. The existing fatigue strain vs. life ({var_epsilon}-N) data were evaluated to establish the effects of various material and loading variables, such as steel type, strain range, strain rate, temperature, and dissolved-oxygen level in

O. K. Chopra; W. J. Shack

2002-01-01

297

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

Microsoft Academic Search

\\u000a In order to avoid a bias toward highly toxic but poorly bioavailable compounds in the effect-directed analysis (EDA) of soils\\u000a and sediments, approaches are discussed to consider bioavailability in EDA procedures. In parallel, complimentary approaches\\u000a for making toxicity identification evaluations (TIEs) more capable of performing high resolution fractionation, toxicant isolation\\u000a and identification are described. These approaches focus on three processes

Werner Brack; Robert M. Burgess

298

Incorporating ecologically relevant measures of pesticide effect for estimating the compatibility of pesticides and biocontrol agents.  

PubMed

The compatibility of biological control agents with pesticides is a central concern in integrated pest management programs. The most common assessments of compatibility consist of simple comparisons of acute toxicity among pest species and select biocontrol agents. A more sophisticated approach, developed by the International Organisation of Biological Control (IOBC), is based on a tiered hierarchy made up of threshold values for mortality and sublethal effects that is used to determine the compatibility of pesticides and biological control agents. However, this method is unable to capture longer term population dynamics, which is often critical to the success of biological control and pest suppression. In this article, we used the delay in population growth index, a measure of population recovery, to investigate the potential impacts that the threshold values for levels of lethal and sublethal effects developed by the IOBC had on three biocontrol agents: sevenspotted lady beetle, Coccinella septempunctata L.; the aphid parasitoid Diaeretiella rapae (M'Intosh), and Fopius arisanus (Sonan), a parasitoid of tephritid flies. Based on life histories of these economically important natural enemies, we established a delay of 1-generation time interval as sufficient to disrupt biological control success. We found that delays equivalent to 1-generation time interval were caused by mortality as low as 50% or reductions of offspring as low as 58%, both values in line with thresholds developed by the IOBC. However, combinations of mortality and reduction of offspring lower than these values (from 32 to 43% each) over a simulated 4-mo period caused significant population delays. Furthermore, the species used in these simulations reacted differently to the same levels of effect. The parasitoid D. rapae was the most susceptible species, followed by F. arisanus and C. septempunctata. Our results indicate that it is not possible to generalize about potential long-term impacts of pesticides on biocontrol agents because susceptibility is influenced by differences in life history variables. Additionally, populations of biocontrol agents may undergo significant damage when mortality approaches 50% or when there is mortality of -30% and a 30% reduction in offspring caused by a sublethal effect. Our results suggest that more ecologically relevant measures of effect such as delays in population growth may advance our knowledge of pesticide impacts on populations of beneficial species. PMID:17849847

Stark, John D; Vargas, Roger; Banks, John E

2007-08-01

299

Electrokinetic injection of ammonium and sulfate ions into sand and kaolinite beds  

Microsoft Academic Search

Electrokinetic remediation is an emerging in-situ remediation technique that employs a low-level direct current (DC) across an electrode system inserted in soil to extract inorganic\\/organic species. The efficiency of electrokinetic injection of a cation (ammonium) from the anode and an anion (sulfate) from the cathode into a fine-grained sand bed and a kaolinite bed is investigated. Electrodes are placed in

Yalcin B. Acar; M. Fazle Rabbi; Elif E. Ozsu

1997-01-01

300

Stability of emulsions of water in oil. I. The correlation between electrokinetic potential and stability  

Microsoft Academic Search

Experiments on W\\/O emulsions of moderate concentration, stabilized with oil-soluble, ionizing stabilizers, show that in these emulsions no correlation exists between stability against flocculation and electrokinetic potential. Although, according to theoretical calculations, energy barriers of over 15 kT are present, if the radius of the dispersed globules is about 1 ? and the electrokinetic potential exceeds 25 mv., they apparently

W. Albers; J. Th. G. Overbeek

1959-01-01

301

Electrokinetic characterization of mixed alumina-titania-silica MF membranes by streaming potential measurements  

Microsoft Academic Search

The electrokinetic properties of ceramic microfiltration membranes are studied under various conditions of pH, ionic strength and ionic species in solution. The modification of the surface acid-basic equilibria is analyzed from the streaming potential measurements. The presence of silica impurities leads to a modification of the membrane electrokinetic behavior: its isoelectric point moves from pH 6.5±0.1 to 4.5±0.1. Zeta potential

A. Szymczyk; P. Fievet; J. C. Reggiani; J. Pagetti

1998-01-01

302

Vasodilating effect and tissue accumulation of prostaglandin E1 incorporated in lipid microspheres on the rat ductus arteriosus.  

PubMed

Prostaglandin E1 incorporated in lipid microspheres (lipo PGE1) was administered to the umbilical vein of neonatal rats. Morphological measurement and quantitative autoradioluminography assessed the relationship between the vasodilating effect and tissue accumulation of lipo PGE1 in the ductus arteriosus. In the morphological measurement under microscopy, the inner diameter ratio of the ductus arteriosus to the main pulmonary artery after infusion of 3H-labeled lipo PGE1 (3H-lipo PGE1) continued to remain significantly higher than that of free 3H-PGE1. Autoradioluminography of the frozen frontal section of neonates after intravenous infusion of 3H-lipo PGE1 for 2 h revealed that the ductus levels of radioactivity were higher than those of free 3H-PGE1 in saline solution, although the blood levels were almost equal. Localization of lipo PGE1 labeled with a lipophilic fluorescent probe, 1,1'-dioctadecyl-3,3,3',3-tetramethyl-indocarbocyanine perchlorate (diI), in the endothelial cells of the ductus arteriosus was confirmed by confocal laser scanning microscopy. These findings suggest that the incorporation of lipid microspheres by the endothelial cells is one of the mechanisms that enables lipo PGE1 to accumulate to higher levels in the ductus tissue and to act more efficiently than free PGE1 in neonatal rats. PMID:10580378

Chino, Y; Minagawa, T; Kohno, Y; Fukushima, K; Momma, K

1999-09-01

303

Electrokinetic Bioprocessor for Concentrating Cells and Molecules  

E-print Network

forces can be applied in microfluidic devices.7 Electrophoresis is the movement of charged particles processor, a global flow field generated by ac electroosmosis transports the embedded particles- cesses in biochemical analysis. For highly dilute samples, an effective collection procedure of targets

Wong, Pak Kin

304

Effects of radiation and fission product incorporation in a yttria-stabilized zirconia based inert matrix fuel  

NASA Astrophysics Data System (ADS)

This work has investigated the irradiation and incorporation effects of fission products in a yttria-stabilized zirconia (YSZ) based inert matrix fuel (IMF). The concept of inert matrix fuel is based on a new strategy for disposition of plutonium generated from the reprocessing of commercial nuclear fuel and the dismantling of nuclear weapons, i.e. using uranium-free oxides to "burn" plutonium and other actinides (Np, Cm, and Am) in reactors. This approach allows direct disposal, without reprocessing, after once-through burn-up. YSZ and MgAl2O4-YSZ composites are among the potential ceramics for IMF due to their high chemical durability and radiation resistance. The research involved investigating the production, nature, and accumulation of irradiation-induced defects, the behavior of the fission products in the ceramics, the structural stability and amorphization resistance of the YSZ during implantation. Ion implantations were conducted with 200--400 keV Cs+, Sr+, I+, Xe+ and Ti+ up to fluences of 1 x 1017/cm 2 at both room temperature and temperatures of 600--700°C. Thermal annealing was subsequently completed after room temperature ion implantations. In situ and ex situ transmission electron microscopy (TEM), optical absorption spectroscopy, photo-luminescence spectroscopy, and electron paramagnetic resonance (EPR) spectroscopy were employed to characterize the irradiation induced defect evolution and analyze the defect structures. Various irradiation effects were observed and determined in the experiments, such as point defects (F type and V type color centers), defect clusters (dislocation loops), cavities (voids and bubbles), the crystalline-to-amorphous transition, and the phase transformation from fluorite to pyrochlore structure. The ion irradiation-induced amorphization mechanism, the retention ability of the fission products, and structural stability of YSZ are discussed in terms of ion incorporation effects, implanted ion radii, and the solubility limits of the ions in the matrix.

Zhu, Sha

305

Effect of nitrogen incorporation on electrical properties of Ti/Au/GaAsN Schottky diodes  

NASA Astrophysics Data System (ADS)

Electrical I-V and C-V-F measurements have used to investigate the behaviour of Ti/Au/GaAsN Schottky diodes, deposited by Molecular Beam Epitaxy, with various nitrogen percent contents. Ideality factor and series resistance were found to increase with increasing N% dilution in GaAs. This was accompanied by a decrease in Schottky barrier height (I-V). The discrepancy found between Schottky barrier heights estimated from I-V and C-V measurements is attributed to a difference in measurements methods and inhomogeneities in barrier height. The peak capacitance behaviour and its dependence on frequency for Schottky diodes with 0.8% N and 1.2% N content was attributed to annihilation of trap levels below midgap. These traps levels associated with those above midgap are responsible for the nondependence of peak capacitance on frequency for Schottky diodes with 0.2% N content. A compensation effect between traps below and above midgap is believed to be taking place. The dependency reappears for Schottky diodes without nitrogen content and is attributed to trap levels below midgap. Capacitance and conductance at high frequency were corrected to eliminate series resistance effect. Interface states density significantly increased when we increased dilute nitride concentration and may play an important role in Ti/Au/GaAsN Schottky diodes at low frequency.

Bachir Bouiadjra, Wadi; Saidane, Abdelkader; Mostefa, Abdelkader; Henini, Mohamed; Shafi, M.

2014-07-01

306

Self-Consistent Approach to Global Charge Neutrality in Electrokinetics: A Surface Potential Trap Model  

NASA Astrophysics Data System (ADS)

In this work, we treat the Poisson-Nernst-Planck (PNP) equations as the basis for a consistent framework of the electrokinetic effects. The static limit of the PNP equations is shown to be the charge-conserving Poisson-Boltzmann (CCPB) equation, with guaranteed charge neutrality within the computational domain. We propose a surface potential trap model that attributes an energy cost to the interfacial charge dissociation. In conjunction with the CCPB, the surface potential trap can cause a surface-specific adsorbed charge layer ?. By defining a chemical potential ? that arises from the charge neutrality constraint, a reformulated CCPB can be reduced to the form of the Poisson-Boltzmann equation, whose prediction of the Debye screening layer profile is in excellent agreement with that of the Poisson-Boltzmann equation when the channel width is much larger than the Debye length. However, important differences emerge when the channel width is small, so the Debye screening layers from the opposite sides of the channel overlap with each other. In particular, the theory automatically yields a variation of ? that is generally known as the "charge regulation" behavior, attendant with predictions of force variation as a function of nanoscale separation between two charged surfaces that are in good agreement with the experiments, with no adjustable or additional parameters. We give a generalized definition of the ? potential that reflects the strength of the electrokinetic effect; its variations with the concentration of surface-specific and surface-nonspecific salt ions are shown to be in good agreement with the experiments. To delineate the behavior of the electro-osmotic (EO) effect, the coupled PNP and Navier-Stokes equations are solved numerically under an applied electric field tangential to the fluid-solid interface. The EO effect is shown to exhibit an intrinsic time dependence that is noninertial in its origin. Under a step-function applied electric field, a pulse of fluid flow is followed by relaxation to a new ion distribution, owing to the diffusive counter current. We have numerically evaluated the Onsager coefficients associated with the EO effect, L21, and its reverse streaming potential effect, L12, and show that L12=L21 in accordance with the Onsager relation. We conclude by noting some of the challenges ahead.

Wan, Li; Xu, Shixin; Liao, Maijia; Liu, Chun; Sheng, Ping

2014-01-01

307

Transport of nanoparticles and reacting biomolecules in micro- and nanofluidic electrokinetic systems  

NASA Astrophysics Data System (ADS)

Micro and nanofluidic systems are ideal platforms for breakthrough bioanalytical tools. In particular, transport in nanoscale channels has been shown to be different than microscale systems because of unique coupled physics associated with wall interactions, electrokinetic surface phenomena and hydrodynamic confinement. Furthermore, understanding the effects of reaction kinetics during capillary electrophoresis is necessary for reliable bioanalytical tools with reacting species. We present experimental data and numerical simulation to elucidate the dominant physics at these lengths scales toward enabling nanofluidic bioanalytical devices. First, we present an experimental study to measure the effect channel height and ionic strength on the electrophoretic mobility of spherical nanoparticles and short single strand (ss) and double strand (ds) DNA with channel depths ranging from 20 microns to 100 nm. We find increased hydrodynamic drag in confinement, nanoparticle rotation effects for spherical analytes in sheer flows, non-uniform electro-osmotic velocity profiles, and electrostatic repulsion of thick electric double layers to be important effects on transport. Second, we present an experimental study of electrokinetic separations of short, complementary ss and dsDNA in microchannels. We find different phenomena are significant for the three different DNA lengths in the study (10nt, 20nt, and 50nt). Reaction kinetic effects are significant for the shortest length DNA, where the melting temperature is comparable to room temperature. For longer 20 and 50nt DNA, the melting temperatures are sufficiently high and reaction kinetic effects are constant. In addition, the 50 nt ssDNA contour length is greater than the persistence length and we find changes in electrophoretic mobility with ionic strength resulting from changes in conformation. Finally, we present numerical simulations of the previous study on separations of reacting DNA. Reaction kinetics can affect the equilibrium ratio of ss to dsDNA which influences transport by shifting the observed electrophoretic mobility of the dsDNA peak away from the true electrophoretic mobility. We perform parametric simulations of relevant parameters and find the initial plug width, analyte concentration and kinetic rate constants are the important parameters on the observed dsDNA peak. In addition, we use our model to determine reaction kinetic parameters (ie KD) of experimental data.

Wynne, Thomas Mikio

308

Electrokinetic In Situ Treatment of Metal-Contaminated Soil  

NASA Technical Reports Server (NTRS)

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.

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

2004-01-01

309

On incorporating damping and gravity effects in models of structural dynamics of the SCOLE configuration  

NASA Technical Reports Server (NTRS)

The damping for structural dynamic models of flexible spacecraft is usually ignored and then added after modal frequencies and mode shapes are calculated. It is common practice to assume the same damping ratio for all modes, although it is known that damping due to bending and that due to torsion are sometimes ignored. Two methods of including damping in the modeling process from its onset are examined. First, the partial derivative equations of motion are analyzed for a pinned-pinned beam with damping. The end conditions are altered to handle bodies with mass and inertia for the Spacecraft Control Laboratory Experiment (SCOLE) configuration. Second, a massless beam approximation is used for the modes with low frequencies, and a clamped-clamped system is used to approximate the modes for arbitrarily high frequency. The model is then modified to include gravity effects and is compared with experimental results.

Taylor, Larry; Leary, Terry; Stewart, Eric

1987-01-01

310

Incorporating cache management behavior into seed dispersal: the effect of pericarp removal on acorn germination.  

PubMed

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

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

2014-01-01

311

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

PubMed Central

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

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

2014-01-01

312

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

SciTech Connect

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.

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

1995-07-01

313

A combination of electrokinetics and Pd/Fe PRB for the remediation of pentachlorophenol-contaminated soil.  

PubMed

Electrokinetic (EK) remediation of pentachlorophenol (PCP)-contaminated soil is difficult because PCP dissociates at different pH values along soil column and shows different transport behaviors near anode and cathode. In the present study, a permeable reactive barrier (PRB) filled with reactive Pd/Fe particles was installed between anode and cathode to reach the dechlorination of PCP during its EK movement. When PRB was installed at the position of 0.3 (normalized distance from anode), PCP in the section from anode to PRB could transport through PRB, while PCP in the section from cathode to PRB was accumulated near PRB. PCP was hardly dechlorinated by PRB wherein high pH was reached. When PRB was installed at the position of 0.5 and the pH in the PRB was decreased by periodical injection of HAc, 49% of PCP was removed, and 22.9% was recovered as phenol which was mostly collected in catholyte. The mechanism of PCP removal was proposed as the EK movement of PCP into the PRB compartment, the complete dechlorination of PCP to phenol by Pd/Fe in the PRB compartment, and the subsequent removal of phenol by electroosmosis. This study proved that the combination of electrokinetics and Pd/Fe PRB was effective for the remediation of PCP-contaminated soil. PMID:21470711

Li, Zhirong; Yuan, Songhu; Wan, Jinzhong; Long, Huayun; Tong, Man

2011-06-01

314

A combination of electrokinetics and Pd/Fe PRB for the remediation of pentachlorophenol-contaminated soil  

NASA Astrophysics Data System (ADS)

Electrokinetic (EK) remediation of pentachlorophenol (PCP)-contaminated soil is difficult because PCP dissociates at different pH values along soil column and shows different transport behaviors near anode and cathode. In the present study, a permeable reactive barrier (PRB) filled with reactive Pd/Fe particles was installed between anode and cathode to reach the dechlorination of PCP during its EK movement. When PRB was installed at the position of 0.3 (normalized distance from anode), PCP in the section from anode to PRB could transport through PRB, while PCP in the section from cathode to PRB was accumulated near PRB. PCP was hardly dechlorinated by PRB wherein high pH was reached. When PRB was installed at the position of 0.5 and the pH in the PRB was decreased by periodical injection of HAc, 49% of PCP was removed, and 22.9% was recovered as phenol which was mostly collected in catholyte. The mechanism of PCP removal was proposed as the EK movement of PCP into the PRB compartment, the complete dechlorination of PCP to phenol by Pd/Fe in the PRB compartment, and the subsequent removal of phenol by electroosmosis. This study proved that the combination of electrokinetics and Pd/Fe PRB was effective for the remediation of PCP-contaminated soil.

Li, Zhirong; Yuan, Songhu; Wan, Jinzhong; Long, Huayun; Tong, Man

2011-06-01

315

Effect of incorporating carbon nanotubes into electrolyte on surface morphology of micro arc oxidized Cp-Ti  

NASA Astrophysics Data System (ADS)

In the present study, effect of carbon nanotubes (CNTs), as electrolyte additives in the micro arc oxidation (MAO) process, on surface morphology of commercially pure titanium (Cp-Ti) was investigated. MAO process was carried out under constant bipolar voltage pulses using two different positive and negative voltage combinations. Results showed that CNTs were successfully incorporated into the coating surface especially within the pores generated by the discharge channels during the MAO process as confirmed by SEM examinations. As the applied voltage and CNTs concentration in the electrolyte were increased, size of micro pores on the surface also increased and their numbers decreased. Higher amount of CNTs addition in the electrolyte resulted in a corresponding decrement in the coating thickness after the MAO process.

Yaz?c?, Selim Kaan; Muhaffel, Faiz; Baydogan, Murat

2014-11-01

316

Incorporating an audience response system into veterinary dermatology lectures: effect on student knowledge retention and satisfaction.  

PubMed

Veterinary educators are charged with delivering large amounts of information to adult students, who benefit from a more interactive learning environment than is often achieved through didactic lectures. Audience response systems (ARS) with wireless keypad technology facilitate interactive learning and have been used successfully in the education of health professionals. The objectives of this pilot study were to determine the effect of an ARS on the knowledge retention of veterinary dermatology students and to survey student attitudes concerning its use. A cohort-controlled trial was conducted to evaluate the potential benefits of ARS for short-term and long-term knowledge retention. Students also participated in four hours of student-directed case simulations using ARS technology. Students were surveyed regarding opinions on the use of the ARS. The mean short-term knowledge-retention test scores of groups A (ARS+) and B (ARS-) were 81% and 78%, respectively. The mean long-term knowledge-retention test scores of groups A and B were 54% and 55%, respectively. The differences between groups were not significant for either time period (p = 0.32, p = 0.77). Although benefits to short-term and long-term knowledge retention were not detected in this pilot study, all students responding to the survey perceived a benefit and supported the use of ARS in the clinical veterinary curriculum. ARS technology provides a tool for lecturers to create an interactive learning environment well suited for teaching veterinary dermatology. PMID:18326780

Plant, Jon D

2007-01-01

317

Effect of annealing on graphene incorporated poly-(3-hexylthiophene):CuInS2 photovoltaic device  

NASA Astrophysics Data System (ADS)

The effect of thermal annealing on the power conversion efficiency (PCE) of poly(3-hexylthiophene) (P3HT):CuInS2 quantum dot:graphene photovoltaic device has been studied by analyzing optical characteristics of composite films and electrical characteristics of the device with structure indium tin oxide/poly[ethylene dioxythiophene]:poly[styrene sulfonate] (ITO/PEDOT:PSS)/P3HT:CIS:graphene/LiF/aluminum. It was observed that after annealing at 120°C for 15 min a typical device containing 0.005 % w/w of graphene shows the best performance with a PCE of 1.3%, an open-circuit voltage of 0.44V, a short-circuit current density of 7.6 mA/cm2, and a fill factor of 0.39. It is observed that the thermal annealing considerably enhances the efficiency of solar cells. However, an annealing at higher temperature such as at 140°C results in a decrease in the device efficiency.

Kumari, Anita; Singh, Inderpreet; Dixit, Shiv Kumar

2014-10-01

318

Effect of transglutaminase on properties of tilapia scale gelatin films incorporated with soy protein isolate.  

PubMed

The effect of transglutaminase (TGase) on the properties of tilapia scale gelatin films in the presence of soy protein isolate (SPI) was investigated. When 3% TGase was added into gelatin films, the total soluble matter and protein solubility of films were decreased from 89.36% and 92.78% to 35.83% and 40.05%, respectively, and the decline was promoted by adding 5% SPI. The strength of the films was increased by adding 1% TGase irrespective of SPI addition, but decreased when the TGase concentration was further raised. No obvious colour change was observed in the films with or without TGase and SPI. Based on the results of SDS-PAGE, DSC and SEM, it was revealed that the movement of low molecular weight hydrophilic protein was depressed by the cross-linking network structure induced by TGase and SPI during film drying, indicating that adding SPI is essential to improve the thermal stability and water resistance properties of TGase-induced gelatin films. PMID:25236224

Weng, Wuyin; Zheng, Huibin

2015-02-15

319

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

SciTech Connect

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.

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

320

Optical spacing effect in organic photovoltaic cells incorporating a dilute acceptor layer  

SciTech Connect

The addition of spacing layers in organic photovoltaic cells (OPVs) can enhance light absorption by optimizing the spatial distribution of the incident optical field in the multilayer structure. We explore the optical spacing effect in OPVs achieved using a diluted electron acceptor layer of C{sub 60}. While optical spacing is often realized by optimizing buffer layer thickness, we find that optical spacing via dilution leads to cells with similar or enhanced photocurrent. This is observed despite a smaller quantity of absorbing molecules, suggesting a more efficient use of absorbed photons. In fact, dilution is found to concentrate optical absorption near the electron donor-acceptor interface, resulting in a marked increase in the exciton diffusion efficiency. Contrasting the use of changes in thickness to engineer optical absorption, the use of dilution does not significantly alter the overall thickness of the OPV. Optical spacing via dilution is shown to be a viable alternative to more traditional optical spacing techniques and may be especially useful in the continued optimization of next-generation, tandem OPVs where it is important to minimize competition for optical absorption between individual sub-cells.

Menke, S. Matthew; Lindsay, Christopher D.; Holmes, Russell J. [Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455 (United States)

2014-06-16

321

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

PubMed Central

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

2014-01-01

322

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

NASA Technical Reports Server (NTRS)

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.

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

2002-01-01

323

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

SciTech Connect

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.

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

324

Effect of Broccoli (Brassica oleracea) Tissue, Incorporated at Different Depths in a Soil Column, on Meloidogyne incognita  

PubMed Central

Brassicas have been used frequently for biofumigation, a pest-management strategy based on the release of biocidal volatiles during decomposition of soil-incorporated tissue. However, the role of such volatiles in control of plant-parasitic nematodes is unclear. The goal of this study was to determine the direct localized and indirect volatile effects of amending soil with broccoli tissue on root-knot nematode populations. Meloidogyne incognita-infested soil in 50-cm-long tubes was amended with broccoli tissue, which was mixed throughout the tube or concentrated in a 10-cm layer. After three weeks at 28°C, M. incognita populations in the amended tubes were 57 to 80% smaller than in non-amended tubes. Mixing broccoli throughout the tubes reduced M. incognita more than concentrating broccoli in a 10-cm layer. Amending a 10-cm layer reduced M. incognita in the non-amended layers of those tubes by 31 to 71%, probably due to a nematicidal effect of released volatiles. However, the localized direct effect was much stronger than the indirect effect of volatiles. The strong direct effect may have resulted from the release of non-volatile nematicidal compounds. Therefore, when using biofumigation with broccoli to control M. incognita, the tissue should be thoroughly and evenly mixed through the soil layer(s) where the target nematodes occur. Effects on saprophytic nematodes were the reverse. Amended soil layers had much greater numbers of saprophytic nematodes than non-amended layers, and there was no indirect effect of amendments on saprophytic nematodes in adjacent non-amended layers. PMID:19259479

Roubtsova, Tatiana; López-Pé?ez, Jose-Antonio; Edwards, Scott; Ploeg, Antoon

2007-01-01

325

Entropic Electrokinetics: Recirculation, Particle Separation, and Negative Mobility  

NASA Astrophysics Data System (ADS)

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.

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

2014-09-01

326

Mechanistic studies of partial-filing micellar electrokinetic chromatography  

SciTech Connect

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.

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

327

Electrokinetic treatment of firing ranges containing tungsten-contaminated soils.  

PubMed

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

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

2007-11-19

328

Surface Charge Development on Transition Metal Sulfides: An Electrokinetic Study  

Microsoft Academic Search

The isoelectric points, pHi.e.p., of ZnS, PbS, CuFeS2, FeS, FeS2, NiS2, CoS2, and MnS2 in NaCl supported electrolyte solutions are estimated to be between pH 3.3 and 0.6, with most of the isoelectric points below pH 2. The first electrokinetic measurements on NiS2, CoS2, and MnS2 are reported here. Below pHi.e.p. the metal-sulfide surfaces are positively charged, above pHi.e.p. the

Joakim Bebie; Martin A. A. Schoonen; Mark Fuhrmann; Daniel R. Strongin

1998-01-01

329

Entropic electrokinetics: recirculation, particle separation, and negative mobility.  

PubMed

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. PMID:25279646

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

2014-09-19

330

Entropic electrokinetics: recirculation, particle separation and negative mobility  

E-print Network

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 nano-metric 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 shading light on their possible relevance in a wide variety of situations, ranging from nano- and micro-fluidic devices to biological systems.

Paolo Malgaretti; Ignacio Pagonabarraga; J. Miguel Rubi

2014-09-23

331

Neutron irradiation and post-irradiation annealing of rutile (TiO 2? x ): effect on hydrogen incorporation and optical absorption  

Microsoft Academic Search

Neutron irradiation and post-irradiation annealing under oxidising and reducing conditions have been used to investigate H incorporation in, and the optical properties of, reduced (TiO2?x\\u000a ) rutile. Optical absorption in rutile is mainly due to a Ti3+ Ti4+ intervalence charge transfer effect. The main mechanism for H incorporation in rutile involves interstitial H not coupled to other defects, which has

Geoffrey David Bromiley; Andrei A. Shiryaev

2006-01-01

332

NC-6300, an epirubicin-incorporating micelle, extends the antitumor effect and reduces the cardiotoxicity of epirubicin.  

PubMed

Epirubicin is widely used to treat various human tumors. However, it is difficult to achieve a sufficient antitumor effect because of dosage limitation to prevent cardiotoxicity. We hypothesized that epirubicin-incorporating micelle would reduce cardiotoxicity and improve the antitumor effect. NC-6300 comprises epirubicin covalently bound to PEG polyaspartate block copolymer through an acid-labile hydrazone bond. The conjugate forms a micellar structure of 40-80 nm in diameter in an aqueous milieu. NC-6300 (10, 15 mg/kg) and epirubicin (10 mg/kg) were given i.v. three times to mice bearing s.c. or liver xenograft of human hepatocellular carcinoma Hep3B cells. Cardiotoxicity was evaluated by echocardiography in C57BL/6 mice that were given NC-6300 (10 mg/kg) or epirubicin (10 mg/kg) in nine doses over 12 weeks. NC-6300 showed a significantly potent antitumor effect against Hep3B s.c. tumors compared with epirubicin. Moreover, NC-6300 also produced a significantly longer survival rate than epirubicin against the liver orthotopic tumor of Hep3B. With respect to cardiotoxicity, epirubicin-treated mice showed significant deteriorations in fractional shortening and ejection fraction. In contrast, cardiac functions of NC-6300 treated mice were no less well maintained than in control mice. This study warrants a clinical evaluation of NC-6300 in patients with hepatocellular carcinoma or other cancers. PMID:23495762

Takahashi, Amane; Yamamoto, Yoshiyuki; Yasunaga, Masahiro; Koga, Yoshikatsu; Kuroda, Jun-ichiro; Takigahira, Misato; Harada, Mitsunori; Saito, Hiroyuki; Hayashi, Tatsuyuki; Kato, Yasuki; Kinoshita, Taira; Ohkohchi, Nobuhiro; Hyodo, Ichinosuke; Matsumura, Yasuhiro

2013-07-01

333

Effects of elemental composition on the incorporation of dietary nitrogen and carbon isotopic signatures in an omnivorous songbird  

SciTech Connect

Pearson, S.F., D.J. Levey, C.H. Greenberg, and C.M. del Rio. 2003. Effects of elemental composition on the incorporation of dietary nitrogen and carbon isotopic signatures in an omnivorous songbird. Oecologia. 135:516-523. The use of stable isotopes to infer diet requires quantifying the relationship between diet and tissues and, in particular, knowing of how quickly isotopes turnover in different tissues and how isotopic concentrations of different food components change (discriminate) when incorporated into consumer tissues. We used feeding trials with wild-caught yellow-rumped warblers (Dendroica coronata) to determine d15N and d13C turnover rates for blood, d15N and d13C diet-tissue discrimination factors, and diet-tissue relationships for blood and feathers. After 3 weeks on a common diet, 36 warblers were assigned to one of four diets differing in the relative proportion of fruit and insects. Plasma half-life estimates ranged from 0.4 to 0.7 days for d13C and from 0.5 to 1.7 days for d15N. Half-life did not differ among diets. Whole blood half-life for d13C ranged from 3.9 to 6.1 days. Yellow-rumped warbler tissues were enriched relative to diet by 1.7.3.6% for nitrogen isotopes and by 1.2 to 4.3% for carbon isotopes, depending on tissue and diet. Consistent with previous studies, feathers were the most enriched and whole blood and plasma were the least enriched or, in the case of carbon, slightly depleted relative to diet. In general, tissues were more enriched relative to diet for birds with high percentages of insects. For all tissues, carbon and nitrogen isotope discrimination factors increased with carbon and nitrogen concentrations of diets. The isotopic signature of plasma increased linearly with the sum of the isotopic signature of the diet and the discrimination factor. Because the isotopic signature of tissues depends on both elemental concentration and isotopic signature of the diet, attempts to reconstruct diet from stable isotope signatures require mixing models that incorporate elemental concentration.

Pearson, Scott, F.; Levey, Douglas, J.; Greenberg, Catheryn, H.; Martinez del Rio, Carlos

2003-02-28

334

Micellar electrokinetic chromatography systems for the separation of mixtures of charged and uncharged compounds.  

PubMed

In this study, the migration behavior of charged and uncharged analytes was investigated under different conditions. Effective mobilities - electrophoretic mobilities under the influence of micelles - of cations, anions, and neutrals were measured at neutral, basic, and acidic pH (7.5, 11, and 2.2) using background electrolytes containing different sodium dodecyl sulfate (SDS) concentrations (0-90 mM) and acetonitrile (ACN) proportions (0-75%). SDS concentration and ACN proportion were found to have a tremendous effect on the effective mobilities and migration order of the model compounds. Although the SDS micelles preferably interact with neutrals and cations, hydrophobic bonds can also occur with anions. Cations, anions, and neutrals having rather different migration behaviors, it is possible to considerably enhance the selectivity of the method by adjusting properly the SDS concentration and the ACN proportion. These observations confirm the interest of using micellar electrokinetic chromatography not only for the separation of neutral substances but also to analyze charged compounds. PMID:22623499

Lamalle, Caroline; Servais, Anne-Catherine; Fradi, Ines; Crommen, Jacques; Fillet, Marianne

2012-08-01

335

Effects of 12-O-tetradecanoylphorbol-13-acetate and retinoids on intercellular junctional communication measured with a citrulline incorporation assay.  

PubMed

Inhibition of intercellular junctional communication by 12-O-tetradecanoylphorbol-13-acetate (TPA) and retinoids was investigated using a citrulline incorporation assay. This new assay uses metabolic co-operation between argininosuccinate lyase-deficient human fibroblasts and arginosuccinate synthetase-deficient cells as a measure of junctional communication. Short-term exposure to TPA resulted in virtually complete inhibition of metabolic co-operation when V79 cells were used as the synthetase-deficient type. When synthetase-deficient human fibroblasts were used, inhibition by TPA was only partial. Exposure to high concentrations of TPA for prolonged periods resulted in partial reversal of communication inhibition and a refractory state in which cells were unresponsive to TPA. Retinoic acid and other retinoids also inhibited metabolic co-operation, but did not cause desensitisation of the type seen with TPA after prolonged exposure. Cultures which had been made refractory to TPA remained sensitive to inhibition by retinoic acid and 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane, indicating that these latter compounds inhibit junctional communication by a mechanism different from TPA. Simultaneous exposure of cultures to TPA and retinoic acid showed that the inhibitory effects on metabolic co-operation of these compounds were additive. Fluocinolone acetonide did not antagonise the effect of TPA. These results suggest that retinoic acid and fluocinolone acetonide exert their anti-tumor-promoting action by mechanisms which are not mediated by intercellular junctional communication. PMID:3986968

Davidson, J S; Baumgarten, I M; Harley, E H

1985-04-01

336

An experimental test of new theoretical models for the electrokinetic properties of biological membranes. The effect of UO2++ and tetracaine on the electrophoretic mobility of bilayer membranes and human erythrocytes.  

PubMed

For a large smooth particle with charges at the surface, the electrophoretic mobility is proportional to the zeta potential, which is related to the charge density by the Gouy-Chapman theory of the diffuse double layer. This classical model adequately describes the dependence of the electrophoretic mobility of phospholipid vesicles on charge density and salt concentration, but it is not applicable to most biological cells, for which new theoretical models have been developed. We tested these new models experimentally by measuring the effect of UO2++ on the electrophoretic mobility of model membranes and human erythrocytes in 0.15 M NaCl at pH 5. We used UO2++ for these studies because it should adsorb specifically to the bilayer surface of the erythrocyte and should not change the density of fixed charges in the glycocalyx. Our experiments demonstrate that it forms high-affinity complexes with the phosphate groups of several phospholipids in a bilayer but does not bind significantly to sialic acid residues. As observed previously, UO2++ adsorbs strongly to egg phosphatidylcholine (PC) vesicles: 0.1 mM UO2++ changes the zeta potential of PC vesicles from 0 to +40 mV. It also has a large effect on the electrophoretic mobility of vesicles formed from mixtures of PC and the negative phospholipid phosphatidylserine (PS): 0.1 mM UO2++ changes the zeta potential of PC/PS vesicles (10 mol % PS) from -13 to +37 mV. In contrast, UO2++ has only a small effect on the electrophoretic mobility of either vesicles formed from mixtures of PC and the negative ganglioside GM1 or erythrocytes: 0.1 mM UO2++ changes the apparent zeta potential of PC/GM1 vesicles (17 mol % GM1) from -11 to +5 mV and the apparent zeta potential of erythrocytes from -12 to -4 mV. The new theoretical models suggest why UO2++ has a small effect on PC/GM1 vesicles and erythrocytes. First, large groups (e.g., sugar moieties) protruding from the surface of the PC/GM1 vesicles and erythrocytes exert hydrodynamic drag. Second, charges at the surface of a particle (e.g., adsorbed UO2++) exert a smaller effect on the mobility than charges located some distance from the surface (e.g., sialic acid residues). PMID:3794637

Pasquale, L; Winiski, A; Oliva, C; Vaio, G; McLaughlin, S

1986-12-01

337

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

SciTech Connect

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.

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

1982-01-01

338

Advances in Modeling Streambank Stability by Incorporating the Mechanical and Hydrologic Effects of Woody and Herbaceous Riparian Vegetation  

NASA Astrophysics Data System (ADS)

Sediment is one of the principle pollutants of surface waters of the United States. Sediment derived from streambanks by mass failure is a significant contributor to water-quality and land management problems. Accurately modeling streambank stability and potential mitigation strategies using riparian vegetation involves quantifying the hydrologic and mechanical factors that control the driving and resisting forces imposed by bank material, ground and surface water and the vegetation. Stabilization of streambanks using riparian vegetation offers numerous potential benefits and some potential problems that are related to mechanical and hydrological effects that are rarely quantified. In this study mechanical reinforcement of various woody and herbaceous riparian species is quantified with in situ, field measurements of root tensile strength, root sizes and root distribution that are used to calculate increases in soil cohesion. Hydrological effects of vegetation are monitored at the Goodwin Creek Experimental Watershed, Mississippi using interception plots and tensiometers under three vegetative covers: cropped grass `control' cover, clumps of eastern gamma grass, and a deciduous woody-vegetation stand. The ARS Bank-Stability Model which accounts for complex bank geometries, up to five soil layers, positive and negative pore-water pressures and confining pressure due to streamflow is used to evaluate the effectiveness of various vegetative treatments based on the field data. The model is used to evaluate the individual and combined effects of vegetation on streambank stability. On April 4 th 2000 prolonged rainfall at the field site caused bank failure at the control cover plot, providing useful validation data for the analysis. The resulting factor of safety (Fs) values (incorporating both hydrological and mechanical effects) were 1.04, 1.64 and 2.18, respectively. Results show that the main contribution of the woody-vegetation to bank stability during the study period was hydrological rather than mechanical, and that the build up of matric suction at depth during the summer months persisted throughout the winter and spring. This effect was due to transpiration rather than canopy interception losses, which were only 2% of rainfall during the study period. The beneficial hydrologic effect of woody vegetation may not be the case during wetter winters; more rapid loss of matric suction beneath woody-vegetation suggests that this bank may become less stable than the control or clump grass treatments due to enhanced infiltration of rainfall.

Simon, A.; Collison, A. J.

2001-12-01

339

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

NASA Astrophysics Data System (ADS)

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.

Contento, Nicholas M.

340

Transient electrokinetic transport in micro/nanofluidic systems with sudden expansion and contraction cross sections  

NASA Astrophysics Data System (ADS)

This study numerically investigates electrokinetic transport in a micro/nanofluidic system by solving the transient Poisson, Nernst-Planck, and Navier-Stokes equations simultaneously. The considered system is a nanochannel connected to two micro channels at its ends. Under various applied electric potential biases, the concentration polarization effect on the fluid flow, induced pressure, and electric current is examined. By comparing with the Donnan equilibrium condition and electroosmotic flow in the microscale dimension, electric body force due to non-zero charge density is the mechanism for producing vortex flow and inducing a positive pressure gradient on the anodic side of the system. The diffusive boundary layer thickness is reduced due to stirring by the generated vortex flow, resulting in over-limiting current when the applied electric potential bias is high. The steady-state current voltage curve indicates that in the Ohmic regime, higher current can be obtained when the surface charge density is large due to higher fluid velocity. In the limiting and over-limiting current regimes, higher electric current can be obtained when the nanochannel is larger with smaller surface density because more ions are available for carrying the current. The nanochannel size effect on the limiting and over-limiting current magnitudes is insignificant when the surface charge density is large.

Chein, Reiyu; Liao, Yuchung

2013-03-01

341

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

PubMed

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

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

2014-09-21

342

Determination of piribedil in pharmaceutical formulations by micellar electrokinetic capillary chromatography.  

PubMed

A fast and simple micellar electrokinetic capillary chromatographic method was developed for the analysis of piribedil in pharmaceutical formulations. The effects of buffer concentration, buffer pH, sodium dodecyl sulphate (SDS) concentration, organic modifier, applied voltage and injection time were investigated. Optimum results were obtained with a 50 mM borate buffer at pH 8.0 containing 50 mM SDS by using a fused silica capillary (50 microm internal diameter, 72 cm effective length). The sample was injected hydrodynamically for 4 s at 50 mbar pressure and the applied voltage was +30 kV. The detection wavelength was set at 205 nm. Diflunisal was used as an internal standard. The analysis was performed at 25 degrees C and the total run time was 14 min. The method was suitably validated with respect to linearity range, limit of detection and quantification, precision, accuracy, specificity and robustness. The linear calibration range was 5-100 microg mL(-1) and the limit of detection was determined as 1 microg mL(-1). The method developed was successfully applied to the determination of piribedil in pharmaceutical formulations. The results were compared with a spectrophotometric method reported in the literature and no significant difference was found statistically. PMID:14985904

Yardimci, Ceren; Süslü, Incilay; Ozaltin, Nuran

2004-05-01

343

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

NASA Astrophysics Data System (ADS)

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.

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

2014-02-01

344

Inhibitory effects of benomyl and carbendazim on the [3H]thymidine incorporation in various organs of the mouse--evidence for a more pronounced action of benomyl.  

PubMed

The benzimidazole fungicides benomyl and carbendazim were compared with regard to effects on [3H]thymidine incorporation in various organs of male mice given the compounds orally at various time intervals before sacrifice. Since carbendazim is a major metabolite of benomyl, it is generally assumed that the fungicidal action and toxicity of these compounds are due to the action of carbendazim. However, whereas benomyl inhibited the [3H]thymidine incorporation into thymus, spleen, liver, kidney and testis, an equimolar amount (3.4 mmol/kg body wt) of carbendazim induced a similar effect only in testis. PMID:2321244

Hellman, B; Laryea, D

1990-04-17

345

Micellar nanotubes dispersed electrokinetic chromatography for the simultaneous determination of antibiotics in bovine milk.  

PubMed

A method to determine four antibiotics for veterinary use (ciprofloxacin, enrofloxacin, florfenicol, and chloramphenicol) of different families (fluoroquinolones and amphenicols) in bovine milk was developed. The determination of the analytes was carried out using micellar electrokinetic capillary chromatography (MEKC) with a common sodium borate-SDS buffer solution containing single-walled carbon nanotubes (SWCNTs). In this way, a great improvement in the electrophoretic resolution and the separation efficiency was achieved compared to MEKC. An online reverse electrode polarity-stacking mode (REPSM) was carried out to enhance sensitivity. This step was performed in only 2 min and it allowed a stacked percentage of 103. That means that all the amount of injected analytes is effectively stacked. When this stacking procedure was combined with an off-line preconcentration step, based on SPE, analytes could be detected in lower concentration than the established maximum residue limits (MRLs). The LODs for the four compounds were between 6.8 and 13.8 ?g L(-1) and the RSD values were between 1.1% and 6.6%. The whole method was applied to spiked real samples with acceptable precision and satisfactory recoveries. PMID:22806472

Springer, Valeria H; Lista, Adriana G

2012-07-01

346

Thrombin Production and Human Neutrophil Elastase Sequestration by Modified Cellulosic Dressings and Their Electrokinetic Analysis  

PubMed Central

Wound healing is a complex series of biochemical and cellular events. Optimally, functional material design addresses the overlapping acute and inflammatory stages of wound healing based on molecular, cellular, and bio-compatibility issues. In this paper the issues addressed are uncontrolled hemostasis and inflammation which can interfere with the orderly flow of wound healing. In this regard, we review the serine proteases thrombin and elastase relative to dressing functionality that improves wound healing and examine the effects of charge in cotton/cellulosic dressing design on thrombin production and elastase sequestration (uptake by the wound dressing). Thrombin is central to the initiation and propagation of coagulation, and elastase is released from neutrophils that can function detrimentally in a stalled inflammatory phase characteristic of chronic wounds. Electrokinetic fiber surface properties of the biomaterials of this study were determined to correlate material charge and polarity with function relative to thrombin production and elastase sequestration. Human neutrophil elastase sequestration was assessed with an assay representative of chronic wound concentration with cotton gauze cross-linked with three types of polycarboxylic acids and one phosphorylation finish; thrombin production, which was assessed in a plasma-based assay via a fluorogenic peptide substrate, was determined for cotton, cotton-grafted chitosan, chitosan, rayon/polyester, and two kaolin-treated materials including a commercial hemorrhage control dressing (QuickClot Combat Gauze). A correlation in thrombin production to zeta potential was found. Two polycarboxylic acid cross linked and a phosphorylated cotton dressing gave high elastase sequestration. PMID:24956451

Edwards, Judson Vincent; Prevost, Nicolette

2011-01-01

347

A Novel Micellar Electrokinetic Chromatographic Method for Separation of Metal-DDTC Complexes  

PubMed Central

Micellar electrokinetic chromatography (MEKC) was examined for the separation and determination of Mo(VI), Cr(VI), Ni(II), Pd(II), and Co(III) as diethyl dithiocarbamate (DDTC) chelates. The separation was achieved from fused silica capillary (52?cm?×?75??m?id) with effective length 40?cm, background electrolyte (BGE) borate buffer pH?9.1 (25?mM), CTAB 30% (100?mM), and 1% butanol in methanol (70?:?30?:?5?v/v/v) with applied voltage of ?10?kV using reverse polarity. The photodiode array detection was achieved at 225?nm. The linear calibration for each of the element was obtained within 0.16–10??g/mL with a limit of detection (LOD) 0.005–0.0167??g/mL. The separation and determination was repeatable with relative standard deviation (RSD) within 2.4–3.3% (n = 4) in terms of migration time and peak height/peak area. The method was applied for the determination of Mo(VI) from potatoes and almond, Ni(II) from hydrogenated vegetable oil, and Co(III) from pharmaceutical preparations with RSD within 3.9%. The results obtained were checked by standard addition and rechecked by atomic absorption spectrometry. PMID:22649320

Mallah, Arfana; Memon, Saima Q.; Solangi, Amber R.; Memon, Najma; Abbassi, Kulsoom; Khuhawar, Muhammad Yar

2012-01-01

348

Thrombin production and human neutrophil elastase sequestration by modified cellulosic dressings and their electrokinetic analysis.  

PubMed

Wound healing is a complex series of biochemical and cellular events. Optimally, functional material design addresses the overlapping acute and inflammatory stages of wound healing based on molecular, cellular, and bio-compatibility issues. In this paper the issues addressed are uncontrolled hemostasis and inflammation which can interfere with the orderly flow of wound healing. In this regard, we review the serine proteases thrombin and elastase relative to dressing functionality that improves wound healing and examine the effects of charge in cotton/cellulosic dressing design on thrombin production and elastase sequestration (uptake by the wound dressing). Thrombin is central to the initiation and propagation of coagulation, and elastase is released from neutrophils that can function detrimentally in a stalled inflammatory phase characteristic of chronic wounds. Electrokinetic fiber surface properties of the biomaterials of this study were determined to correlate material charge and polarity with function relative to thrombin production and elastase sequestration. Human neutrophil elastase sequestration was assessed with an assay representative of chronic wound concentration with cotton gauze cross-linked with three types of polycarboxylic acids and one phosphorylation finish; thrombin production, which was assessed in a plasma-based assay via a fluorogenic peptide substrate, was determined for cotton, cotton-grafted chitosan, chitosan, rayon/polyester, and two kaolin-treated materials including a commercial hemorrhage control dressing (QuickClot Combat Gauze). A correlation in thrombin production to zeta potential was found. Two polycarboxylic acid cross linked and a phosphorylated cotton dressing gave high elastase sequestration. PMID:24956451

Edwards, Judson Vincent; Prevost, Nicolette

2011-01-01

349

Dispersion stability and electrokinetic properties of intrinsic plutonium colloids: implications for subsurface transport.  

PubMed

Subsurface transport of plutonium (Pu) may be facilitated by the formation of intrinsic Pu colloids. While this colloid-facilitated transport is largely governed by the electrokinetic properties and dispersion stability (resistance to aggregation) of the colloids, reported experimental data is scarce. Here, we quantify the dependence of ?-potential of intrinsic Pu(IV) colloids on pH and their aggregation rate on ionic strength. Results indicate an isoelectric point of pH 8.6 and a critical coagulation concentration of 0.1 M of 1:1 electrolyte at pH 11.4. The ?-potential/pH dependence of the Pu(IV) colloids is similar to that of goethite and hematite colloids. Colloid interaction energy calculations using these values reveal an effective Hamaker constant of the intrinsic Pu(IV) colloids in water of 1.85 × 10(-19) J, corresponding to a relative permittivity of 6.21 and refractive index of 2.33, in agreement with first principles calculations. This relatively high Hamaker constant combined with the positive charge of Pu(IV) colloids under typical groundwater aquifer conditions led to two contradicting hypotheses: (a) the Pu(IV) colloids will exhibit significant aggregation and deposition, leading to a negligible subsurface transport or (b) the Pu(IV) colloids will associate with the relatively stable native groundwater colloids, leading to a considerable subsurface transport. Packed column transport experiments supported the second hypothesis. PMID:23675849

Abdel-Fattah, Amr I; Zhou, Dongxu; Boukhalfa, Hakim; Tarimala, Sowmitri; Ware, S Doug; Keller, Arturo A

2013-06-01

350

3D numerical simulation of a Coulter counter array with analysis of electrokinetic forces.  

PubMed

Coulter counters have played an important role in biological cell assays since their introduction decades ago. Several types of high throughput micro-Coulter counters based on lab-on-chip devices have been commercialized recently. In this paper, we propose a highly integrated micro-Coulter counter array working under low DC voltage. The real-time electrical current change, including the pulse amplitude and width, of the micro-Coulter counter with novel structure is systematically investigated numerically. The major types of forces exerted on the particle in the micro-Coulter counter, including hydrodynamic force and electrokinetic force are quantitatively analyzed. The simulation in this study shows the pulse profile, such as width and amplitude, is affected by both particle size and the flow condition. The special cases of multiple particle aggregation and cross-talk between neighboring channels are also considered for their effects on the electric current pulses. This simulation provides critical insight and guidance for developing next new generations of micro-Coulter counter. PMID:23161097

Guo, Jinhong; Pui, Tze Sian; Rahman, Abdur Rub Abdur; Kang, Yuejun

2013-02-01

351

Comparison of monolithic capillary electrochromatography and micellar electrokinetic chromatography for the separation of polycyclic aromatic hydrocarbons.  

PubMed

Atmospheric pollution of anthropic origin is recognized as a major risk factor for health, in particular for respiratory and cardio-vascular systems. Among these pollutants, polycyclic aromatic hydrocarbons (PAHs) are placed on the list of US Environmental Protection Agency (EPA) as 'priority' pollutants and four of them are assigned as potential carcinogens by The International Agency for Research on Cancer (IARC). In the present work two capillary techniques-micellar electrokinetic chromatography (MEKC) and monolithic capillary electrochromatography (CEC)-were compared for the separation of eleven PAHs. Both techniques compared in the present work are fully compatible with every standard apparatus of capillary electrophoresis. For MEKC, enhancement of selectivity and decrease of the separation window of eleven PAHs were obtained with methanol:borate 25 mM (20/80, v/v) running buffer containing 10 mM of hydroxypropylated ?-cyclodextrins with low SDS content (25 mM). In case of CEC, two acrylate-based monolithic stationary phases (MSPs) were evaluated for their application in the separation of eleven PAHs. The best MSP based on butyl acrylate was compared with MEKC in terms of sample capacity, PAHs elution order, LOQ, efficiency and effect of pH. Influence of the hydrophobicity of mobile phase on the PAHs elution order was also studied. PMID:24720981

Salwi?ski, Aleksander; Delépée, Raphaël

2014-05-01

352

Imaging the electro-kinetic response of biological tissues with optical coherence tomography.  

PubMed

We demonstrate the feasibility of using optical coherence tomography (OCT) to detect and image an electro-kinetic response: electric-field induced optical changes (EIOC) in soft biological tissues. A low-frequency electric field was applied to ex vivo samples of porcine heart tissues, while OCT signals were acquired continuously. Experimental results show that the amplitude of the OCT signal change is proportional to the amplitude and inversely proportional to the frequency of the applied electric field. We show that the nonconductive component of the sample was eliminated in the normalized EIOC image. To the best our knowledge, this is the first time a two-dimensional image related to the electro-kinetic response of soft tissues is obtained with depth resolution. Since electro-kinetic properties can change during cancerogenesis, EIOC imaging can potentially be used for cancer detection. PMID:23939115

Wawrzyn, K; Demidov, V; Vuong, B; Harduar, M K; Sun, C; Yang, V X D; Doganay, O; Toronov, V; Xu, Y

2013-07-15

353

Using electrokinetic phenomena and electrical resistance tomography to characterize the movement of subsurface fluids  

DOEpatents

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.

Ramirez, A.L.; Cooper, J.F.; Daily, W.D.

1996-02-27

354

Soft particle analysis of electrokinetics of biological cells and their model systems  

NASA Astrophysics Data System (ADS)

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.

Makino, Kimiko; Ohshima, Hiroyuki

2011-03-01

355

Using electrokinetic phenomena and electrical resistance tomography to characterize the movement of subsurface fluids  

DOEpatents

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.

Ramirez, Abelardo L. (Pleasanton, CA); Cooper, John F. (Oakland, CA); Daily, William D. (Livermore, CA)

1996-01-01

356

Simulation-based design of a strained graphene field effect transistor incorporating the pseudo magnetic field effect  

SciTech Connect

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.

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

357

Recent developments in electrokinetically driven analysis on microfabricated devices.  

PubMed

This review is devoted to the rapid developments in the field of microfluidic separation devices in which the flow is electrokinetically driven, and where the separation element forms the heart of the system, in order to give an overview of the trends of the last three years. Examples of microchip layouts that were designed for various application areas are given. Optimization of mixing and injection strategies, designs for the handling of multiple samples, and capillary array systems show the enormous progress made since the first proof-of-concept papers about lab-on-a-chip devices. Examples of functional elements for on-chip preconcentration, filtering, DNA amplification and on-chip detection indicate that the real integration of various analytical tasks on a single microchip is coming into reach. The use of materials other than glass, such as poly(dimethylsiloxane) and polymethylmethacrylate, for chip fabrication and detection methods other than laser-induced fluorescence (LIF) detection, such as mass spectrometry and electrochemical detection, are described. Furthermore, it can be observed that the separation modes known from capillary electrophoresis (CE) in fused-silica capillaries can be easily transferred to the microchip platform. The review concludes with an overview of applications of microchip CE and with a brief outlook. PMID:11192117

Bruin, G J

2000-12-01

358

Physicochemical and electrokinetic properties of silica/lignin biocomposites.  

PubMed

A new method of synthesis of novel composites obtained from silica and Kraft lignin has been proposed. Silica used in the study was obtained by three methods (hydrolysis and condensation of tetraethoxysilane, precipitation in a nonpolar and polar medium with the use of sodium silicate). To extend the possible range of applications, the silica was preliminary modified with N-2-(aminoethyl)-3-aminopropyltrimethoxsysilane, and finally it was modified with Kraft lignin earlier oxidised with sodium periodate (lignin bonded to SiO2 by covalent interactions). The products physicochemical and electrokinetic properties were thoroughly analysed. The dispersive properties and surface morphology were evaluated on the basis of particle size distributions and SEM images. The stability of dispersion in inorganic-organic systems were characterised on the basis of the zeta potential, whose value also permitted concluding on the interactions between colloidal molecules dispersed in water solutions. The products were subjected to elemental analysis to get percentage contents of N, C, H, S elements and were also characterised by XPS and FT-IR spectroscopy. Results of the study are of practical importance in prospective applications of SiO2/lignin biocomposites. PMID:23544548

Klapiszewski, ?ukasz; Nowacka, Magdalena; Milczarek, Grzegorz; Jesionowski, Teofil

2013-04-15

359

Micellar electrokinetic capillary chromatography of benzodiazepines in human urine.  

PubMed

The determination of the major urinary compounds of eight common benzodiazepines, flunitrazepam, diazepam, midazolam, clonazepam, bromazepam, temazepam, oxazepam, and lorazepam, by micellar electrokinetic capillary chromatography (MECC) is shown to be a simple and attractive approach for confirmation testing of these drugs in human urine. After enzymatic hydrolysis and extraction using mixed-mode solid-phase cartridges and a two-step elution protocol, fractions were analyzed in a phosphate/borate buffer (pH 9.3) containing 75 mM sodium dodecyl sulfate and small amounts of isopropanol, methanol and/or acetonitrile using an instrument with on- column multi-wavelength detection. The presence of these compounds could unambiguously be confirmed in patient urines which tested positive for benzodiazepines using a commercial enzyme multiplied immunoassay screening technique (EMIT). The sensitivity of the MECC assay is demonstrated to be better than that of EMIT. MECC analysis of one patient urine which tested negatively employing EMIT revealed the presence of lorazepam, this demonstrating that false-negative results from the initial immunological screening process can be recognized using MECC. For one example, 7-aminoflunitrazepam, the MECC data are shown to agree well with those obtained by gas chromatography/mass spectrometry. PMID:8143683

Schafroth, M; Thormann, W; Allemann, D

1994-01-01

360

Enhanced Transport of Materials into Enamel Nanopores via Electrokinetic Flow.  

PubMed

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

Gan, H Y; Sousa, F B; Carlo, H L; Maciel, P P; Macena, M S; Han, J

2015-04-01

361

AC electrokinetic manipulation of selenium nanoparticles for potential nanosensor applications  

SciTech Connect

Highlights: ? Se nanoparticles were synthesized using a reverse-microemulsion process. ? AC osmotic fluid flow repulses the particles from electrode edges. ? Dielectrophoretic force attracts the particles to electrode edges. ? Dielectrophoresis electrode showed non-ohmic behavior. ? The device can potentially be used as a nanosensor. - Abstract: We report the AC electrokinetic behavior of selenium (Se) nanoparticles for electrical characterization and possible application as micro/nano devices. selenium Se nanoparticles were successfully synthesized using a reverse-microemulsion process and investigated structurally using X-ray diffraction and transmission electron microscope. Interdigitated castellated ITO and non-castellated platinum electrodes were employed for manipulation of suspended materials in the fluid. Using ITO electrodes at low frequency limits resulted in deposition of Se particles on electrode surface. When Se particles exposed to platinum electrodes in the 10 Hz–1 kHz range and V {sub p?p}> 8, AC osmotic fluid flow repulses the particles from electrode edges. However, in 10 kHz–10 MHz range and V {sub p?p}> 5, dielectrophoretic force attracts the particles to electrode edges. As the Se particle concentration increased, the trapped Se particles were aligned along the electric field line and bridged the electrode gap. The device was characterized and can potentially be useful in making micro/nano electronic devices.

Mahmoodi, Seyed Reza [School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Bayati, Marzieh, E-mail: m-bayati@tums.ac.ir [School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Hosseinirad, Somayeh [School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Foroumadi, Alireza [Department of Medicinal Chemistry, Faculty of Pharmacy and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Gilani, Kambiz [Department of Pharmaceutics, School of Pharmacy, Tehran University of Medical Science, Tehran (Iran, Islamic Republic of); Rezayat, Seyed Mahdi [School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of)

2013-03-15

362

Electrokinetic properties of soil minerals and soils modified with polyelectrolytes  

NASA Astrophysics Data System (ADS)

The formation features of nanoadsorption polyelectrolyte (PE) layers with the formation of a mineral-organic matrix on the surface of clay minerals and soils (kaolinite, montmorillonite, quartz sand, gray forest soil, and chernozemic soil) have been elucidated by direct adsorption measurements. It has been found that the experimental values for the limit adsorption of polyacrylamide (PAM) and polyacrylic acid (PAA) on all the minerals are significantly higher than the calculated values for the formation of a monolayer. This indicates adsorption on the surface of not only separate macromolecules but also secondary PE structures as packets or fibrils determining the cluster-matrix structure of the modified surface. The study of the electro-surface properties (electrophoretic mobility, electrokinetic potential, pH, and electroconductivity) of mineral and soil particles adsorption-modified with PEs has confirmed the differences in the adsorption mechanisms (from physical sorption to chemisorption) with the formation of surface compounds depending on the different polar groups of PEs and the mineral type.

Kurochkina, G. N.; Pinskii, D. L.; Haynos, M.; Sokolowska, Z.; Tsesla, I.

2014-07-01

363

42 CFR 137.48 - What is the effect of incorporating a Title I provision into a compact or funding agreement?  

Code of Federal Regulations, 2012 CFR

...incorporating a Title I provision into a compact or funding agreement? 137.48 Section 137.48 Public...AND HUMAN SERVICES TRIBAL SELF-GOVERNANCE Funding Agreements Terms in A Funding Agreement § 137.48 What is the effect...

2012-10-01

364

42 CFR 137.48 - What is the effect of incorporating a Title I provision into a compact or funding agreement?  

Code of Federal Regulations, 2013 CFR

...incorporating a Title I provision into a compact or funding agreement? 137.48 Section 137.48 Public...AND HUMAN SERVICES TRIBAL SELF-GOVERNANCE Funding Agreements Terms in A Funding Agreement § 137.48 What is the effect...

2013-10-01

365

42 CFR 137.48 - What is the effect of incorporating a Title I provision into a compact or funding agreement?  

Code of Federal Regulations, 2010 CFR

...incorporating a Title I provision into a compact or funding agreement? 137.48 Section 137.48 Public...AND HUMAN SERVICES TRIBAL SELF-GOVERNANCE Funding Agreements Terms in A Funding Agreement § 137.48 What is the effect...

2010-10-01

366

42 CFR 137.48 - What is the effect of incorporating a Title I provision into a compact or funding agreement?  

Code of Federal Regulations, 2011 CFR

...incorporating a Title I provision into a compact or funding agreement? 137.48 Section 137.48 Public...AND HUMAN SERVICES TRIBAL SELF-GOVERNANCE Funding Agreements Terms in A Funding Agreement § 137.48 What is the effect...

2011-10-01

367

42 CFR 137.48 - What is the effect of incorporating a Title I provision into a compact or funding agreement?  

Code of Federal Regulations, 2014 CFR

...incorporating a Title I provision into a compact or funding agreement? 137.48 Section 137.48 Public...AND HUMAN SERVICES TRIBAL SELF-GOVERNANCE Funding Agreements Terms in A Funding Agreement § 137.48 What is the effect...

2014-10-01

368

Effect of surfactant Sb on In incorporation and thin film morphology of InGaN layers grown by organometallic vapor phase epitaxy  

E-print Network

Effect of surfactant Sb on In incorporation and thin film morphology of InGaN layers grown. Biefeld Available online 11 April 2013 Keywords: A3. Organometallic vapor phase epitaxy A3. Surfactant of the surfactant Sb on InGaN grown by organometallic vapor phase epitaxy (OMVPE) were studied. Eight samples of In

Simons, Jack

369

Seismic Hazard Maps for Seattle, Washington, Incorporating 3D Sedimentary Basin Effects, Nonlinear Site Response, and Rupture Directivity  

USGS Publications Warehouse

This report presents probabilistic seismic hazard maps for Seattle, Washington, based on over 500 3D simulations of ground motions from scenario earthquakes. These maps include 3D sedimentary basin effects and rupture directivity. Nonlinear site response for soft-soil sites of fill and alluvium was also applied in the maps. The report describes the methodology for incorporating source and site dependent amplification factors into a probabilistic seismic hazard calculation. 3D simulations were conducted for the various earthquake sources that can affect Seattle: Seattle fault zone, Cascadia subduction zone, South Whidbey Island fault, and background shallow and deep earthquakes. The maps presented in this document used essentially the same set of faults and distributed-earthquake sources as in the 2002 national seismic hazard maps. The 3D velocity model utilized in the simulations was validated by modeling the amplitudes and waveforms of observed seismograms from five earthquakes in the region, including the 2001 M6.8 Nisqually earthquake. The probabilistic seismic hazard maps presented here depict 1 Hz response spectral accelerations with 10%, 5%, and 2% probabilities of exceedance in 50 years. The maps are based on determinations of seismic hazard for 7236 sites with a spacing of 280 m. The maps show that the most hazardous locations for this frequency band (around 1 Hz) are soft-soil sites (fill and alluvium) within the Seattle basin and along the inferred trace of the frontal fault of the Seattle fault zone. The next highest hazard is typically found for soft-soil sites in the Duwamish Valley south of the Seattle basin. In general, stiff-soil sites in the Seattle basin exhibit higher hazard than stiff-soil sites outside the basin. Sites with shallow bedrock outside the Seattle basin have the lowest estimated hazard for this frequency band.

Frankel, Arthur D.; Stephenson, William J.; Carver, David L.; Williams, Robert A.; Odum, Jack K.; Rhea, Susan

2007-01-01

370

Multi-vortical flow inducing electrokinetic instability in ion concentration polarization layer  

NASA Astrophysics Data System (ADS)

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

Kim, Sung Jae; Ko, Sung Hee; Kwak, Rhokyun; Posner, Jonathan D.; Kang, Kwan Hyoung; Han, Jongyoon

2012-11-01

371

Effect of Hyaluronic Acid Incorporation Method on the Stability and Biological Properties of Polyurethane-Hyaluronic Acid Biomaterials  

PubMed Central

The high failure rate of small diameter vascular grafts continues to drive the development of new materials and modification strategies that address this clinical problem, with biomolecule incorporation typically achieved via surface-based modification of various biomaterials. In this work, we examined whether the method of biomolecule incorporation (i.e., bulk vs. surface modification) into a polyurethane (PU) polymer impacted biomaterial performance in the context of vascular applications. Specifically, hyaluronic acid (HA) was incorporated into a poly(ether urethane) via bulk copolymerization or covalent surface tethering, and the resulting PU-HA materials characterized with respect to both physical and biological properties. Modification of PU with HA by either surface or bulk methods yielded materials that, when tested under static conditions, possessed no significant differences in their ability to resist protein adsorption, platelet adhesion, and bacterial adhesion, while supporting endothelial cell culture. However, only bulk-modified PU-HA materials were able to fully retain these characteristics following material exposure to flow, demonstrating a superior ability to retain the incorporated HA and minimize enzymatic degradation, protein adsorption, platelet adhesion, and bacterial adhesion. Thus, despite bulk methods rarely being implemented in the context of biomolecule attachment, these results demonstrate improved performance of PU-HA upon bulk, rather than surface, incorporation of HA. Although explored only in the context of PU-HA, the findings revealed by these experiments have broader implications for the design and evaluation of vascular graft modification strategies. PMID:24276670

Ruiz, Amaliris; Rathnam, Kashmila R.; Masters, Kristyn S.

2014-01-01

372

Dose and time dependent effects of morphine on the incorporation of (3H)valine into soluble brain and liver proteins  

SciTech Connect

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.

Roennbaeck, L.; Hansson, E.; Cupello, A.

1983-03-01

373

Effect of Ca incorporation on the dielectric nonlinear behavior of (Ba, Ca)TiO3 multi layer ceramic capacitors  

NASA Astrophysics Data System (ADS)

The difference in the dielectric nonlinearity was investigated by contrasting BaTiO3 and (Ba0.925Ca0.075)TiO3 multilayer ceramic capacitors utilizing the first order reversal curve (FORC) distribution based on the Preisach model. Ca incorporation caused a decrease of the dielectric constants in the low field but little differences in the high field region resulting in a steep ac field dependence, which became more significant with the decrease of temperature. Such behavior can be correlated with a decrease of the reversible and an increase of the irreversible FORC distribution near origin by Ca incorporation. These results suggest that Ca incorporation, which is known to cause the asymmetric off-center displacement at Ba-site, has the role of weakly pinning centers that increase the portion of irreversible domain walls that are immobile at low field but can contribute to polarization beyond a threshold field.

Yoon, Seok-Hyun; Park, Yunjung; Kim, Chang-Hoon; Kim, Doo-Young

2014-12-01

374

Incorporating Climate Change Effects into Next-Generation Coastal Inundation Decision Support Systems: An Integrated and Community-Based Approach  

NASA Astrophysics Data System (ADS)

75% of the world population lives within 100 km from the coastline. Coastal communities are subject to increasing coastal inundation risk due to the combined effects of hurricane-induced storm surge, tsunami, climate change, and sea level rise. This study is developing the next generation decision support systems (DSS) for storm surge and coastal inundation by incorporating the climate change impacts on hurricanes and sea level rise (SLR) along the Florida and North Carolina coast. Using a new methodology (instead of the "bath tub" approach) enhanced by the Institute for Sustainable Coastal Environment and Infrastructure (InSCEI) at University of Florida (UF), highly accurate and efficient coastal inundation maps (Base Flood Elevations and Surge Atlas) are being produced for current climate conditions. Atmospheric and climate scientists at Florida State University (FSU) and North Carolina State University (NCSU) are using global (FSU/COAPS) and regional (WRF) atmospheric models to estimate the range in hurricane activities during 2020-2040 and 2080-2100, using projected SSTs from the IPCC CMIP5 climate scenarios as lower boundary conditions. SLR experts at NCSU and FSU are analyzing historical sea level data and conducting numerical modeling to estimate the SLR at the coastal boundaries for the same IPCC scenarios. UF and NCSU are using the hurricane ensembles and the SLR scenarios provided by FSU and NCSU as input to storm surge and inundation models (CH3D-SSMS and CMAEPS, respectively) to produce high resolution inundation maps which include climate change effects. These future-climate coastal inundation maps will be much more accurate than the current ones and greatly improve the stakeholders' ability to mitigate coastal inundation risk throughout the U.S. and the world. These inundation maps for current and future climates will be communicated to a wide spectrum of stakeholders for feedback and further improvement. A national workshop will be held in January 2013 to engage stakeholders, researchers, and managers (federal, state, and local) of coastal inundation to develop strategies to improve communications among the various entities and to gather inputs on the development of the next -generation coastal inundation decision support system.

Sheng, Y.; Davis, J. R.; Paramygin, V. A.; LaRow, T.; Chassignet, E.; Stefanova, L. B.; Lu, J.; Xie, L.; Montalvo, S.; Liu, J.; Liu, B.

2012-12-01

375

An approximation of herd effect due to vaccinating children against seasonal influenza – a potential solution to the incorporation of indirect effects into static models  

PubMed Central

Background Indirect herd effect from vaccination of children offers potential for improving the effectiveness of influenza prevention in the remaining unvaccinated population. Static models used in cost-effectiveness analyses cannot dynamically capture herd effects. The objective of this study was to develop a methodology to allow herd effect associated with vaccinating children against seasonal influenza to be incorporated into static models evaluating the cost-effectiveness of influenza vaccination. Methods Two previously published linear equations for approximation of herd effects in general were compared with the results of a structured literature review undertaken using PubMed searches to identify data on herd effects specific to influenza vaccination. A linear function was fitted to point estimates from the literature using the sum of squared residuals. Results The literature review identified 21 publications on 20 studies for inclusion. Six studies provided data on a mathematical relationship between effective vaccine coverage in subgroups and reduction of influenza infection in a larger unvaccinated population. These supported a linear relationship when effective vaccine coverage in a subgroup population was between 20% and 80%. Three studies evaluating herd effect at a community level, specifically induced by vaccinating children, provided point estimates for fitting linear equations. The fitted linear equation for herd protection in the target population for vaccination (children) was slightly less conservative than a previously published equation for herd effects in general. The fitted linear equation for herd protection in the non-target population was considerably less conservative than the previously published equation. Conclusions This method of approximating herd effect requires simple adjustments to the annual baseline risk of influenza in static models: (1) for the age group targeted by the childhood vaccination strategy (i.e. children); and (2) for other age groups not targeted (e.g. adults and/or elderly). Two approximations provide a linear relationship between effective coverage and reduction in the risk of infection. The first is a conservative approximation, recommended as a base-case for cost-effectiveness evaluations. The second, fitted to data extracted from a structured literature review, provides a less conservative estimate of herd effect, recommended for sensitivity analyses. PMID:23339290

2013-01-01

376

Removal of contaminants from fine grained soils using electrokinetic (EK) flushing. Final report, September 30, 1987--June 30, 1993  

SciTech Connect

Recently, attention has focused on developing cost effective techniques to remove inorganic contaminants from soils in-situ. For most in-situ techniques hydraulic pressure is used to disperse the chemical additives and collect the contaminated groundwater. In-situ treatment technologies have had success at sites containing sandy soils but have not shown much promise for soils with large amounts of clay and silt. This is due primarily to difficulty in transporting groundwater, contaminants, and chemical additives through the subsurface. Unfortunately, soils high in clay and silt are known to sequester large quantities of inorganic and organic contaminants. Thus, soils having low hydraulic conductivity`s are generally efficient in sequestering pollutants but are resistant to standard in-situ remediation techniques because of the difficulty in transporting groundwater and contaminants. A candidate technology for the in-situ remediation of low permeability soils is electrokinetic (EK) soil flushing. In EK soil flushing, groundwater and contaminants are transported under an a plied voltage. The transport of groundwater electroosmotically does not depend directly on the soil`s hydraulic conductivity. Thus, soils that would otherwise require excavation and treatment can be remediated in-situ if electrokinetics is used as the driving force for liquid and contaminant transport. This report details the results from work conducted on the use of EK soil flushing to remediate a fine grained soil contaminated with lead. The first portion of the experimental work entailed soil collection and characterization, soil adsorption and desorption of lead, and EK reactor construction and testing. The second phase of the research consisted of investigating the efficacy of using EK soil flushing on an actual soil using bench-scale EK reactors. For the second phase of the research the affect of initial conditions on the efficiency of EK soil flushing was studied.

Reed, B.E.; Berg, M.T.

1993-10-01

377

Application of iron electrode corrosion enhanced electrokinetic-Fenton oxidation to remediate diesel contaminated soils: A laboratory feasibility study  

NASA Astrophysics Data System (ADS)

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.

Tsai, Tzai-Tang; Sah, Jygau; Kao, Chih-Ming

2010-01-01

378

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...

379

On the effects of circulation, sediment resuspension and biological incorporation by diatoms in an ocean model of aluminium*  

NASA Astrophysics Data System (ADS)

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.

van Hulten, M. M. P.; Sterl, A.; Middag, R.; de Baar, H. J. W.; Gehlen, M.; Dutay, J.-C.; Tagliabue, A.

2014-07-01

380

Mutagenic effect of radionuclides incorporated into DNA of Drosophila melanogaster. Progress report, December 15, 1982-July 15, 1983  

SciTech Connect

The molecular changes in DNA of mutations induced at the well-defined locus alcohol dehydrogenase (Adh) in Drosophila melanogaster were compared between null mutants induced by x-rays, the alkylating agent N-ethyl-N-nitrosourea (ENU) and decay of tritium incorporated into specific sites of DNA. (ACR)

Lee, W.R.

1983-01-01

381

A three-scale model for ionic solute transport in swelling clays incorporating ion-ion correlation effects  

NASA Astrophysics Data System (ADS)

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.

Le, Tien Dung; Moyne, Christian; Murad, Marcio A.

2015-01-01

382

[Effect of actinomycin D and sibiromycin on 3H-thymidine incorporation into the early developmental stages of Nereis virens Sars].  

PubMed

The Nereis virens embryos at the stages of 2, 8, 16 and 32 blastomeres end of cleavage and beginning of rotation were placed in the actinomycin D or sibiromycin solutions and the effect of antibiotics on 3H-thymidine incorporation during cleavage, at the beginning of rotation and in trochophore was determined by means of autoradiography after careful washing the embryos off. Under the effect of actinomycin D the intensity of 3H-thymidine incorporation during cleavage decreased insignificantly, at the gastrula stage somewhat exceeded that in the control, and at the stages of trochophore formation decreased twice. At the later stages it approached the normal level. In the experiments with sibiromycin which proved to have more distinct inhibitory effect, the stage of trochophore formation was also found to be the most sensitive to the antibiotic. PMID:578569

Donua, A K; Fedorova, Zh E

1977-01-01

383

Effects of Cholesterol Incorporation on the Physicochemical, Colloidal, and Biological Characteristics of pH-sensitive AB2 Miktoarm Polymer-Based Polymersomes  

PubMed Central

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

Yin, Haiqing; Kang, Han Chang; Huh, Kang Moo; Bae, You Han

2014-01-01

384

Incorporation and effects of dietary eicosapentaenoate (20:5(n-3)) on plasma and erythrocyte lipids of the marmoset following dietary supplementation with differing levels of linoleic acid.  

PubMed

The effect of dietary eicosapentaenoic acid (EPA, 20:5(n-3), as the ethyl ester) on plasma lipid levels and the incorporation of EPA into erythrocyte and plasma lipids were investigated in the marmoset monkey. Marmosets were fed high mixed-fat diets (14.5% total fat) supplemented with or without 0.8% EPA for 30 weeks. Markedly elevated plasma cholesterol (16.4 mmol/l) was induced by an atherogenic-type diet but with EPA supplementation, plasma cholesterol increased to only 6.6 mmol/l. Plasma triacylglycerol levels were not elevated with an atherogenic type diet. Substantial EPA incorporation was evident for plasma phospholipid, triacylglycerol and cholesterol ester fractions. The proportion of docosapentaenoic acid (22:5(n-3)) but not docosahexaenoic acid (22:6(n-3)) was also elevated in these plasma lipid fractions. Greatest incorporation of EPA occurred when it was administered with an atherogenic type diet having a P:M:S (polyunsaturated:monounsaturated:saturated) fatty acid ratio of about 0.2:0.6:1.0 in comparison to the control diet of 1.0:1.0:1.0. Incorporation of EPA and 22:5(n-3)) into erythrocyte phospholipids was also apparent and this was at the expense of linoleic acid (18:2(n-6)). These results in the marmoset highlight both the cholesterol-lowering properties of EPA and the extent of its incorporation into plasma lipids and erythrocyte membrane phospholipids with far greater incorporation occurring when the level of dietary linoleic acid was reduced. PMID:2378908

McMurchie, E J; Rinaldi, J A; Burnard, S L; Patten, G S; Neumann, M; McIntosh, G H; Abbey, M; Gibson, R A

1990-07-16

385

Numeric Simulation of Heat Transfer and Electrokinetic Flow in an Electroosmosis-Based  

E-print Network

Numeric Simulation of Heat Transfer and Electrokinetic Flow in an Electroosmosis-Based Continuous is dedicated to under- standing the fluid flow and heat transfer mechanisms occurring in continuous flow PCR are discussed in detail. The importance of each heat transfer mechanism for different situations is also

Le Roy, Robert J.

386

PROOF COPY 022212PHF Nonlinear electrokinetic ejection and entrainment due to polarization  

E-print Network

PROOF COPY 022212PHF PROOF COPY 022212PHF Nonlinear electrokinetic ejection and entrainment due from dielectric materials whose permittivity is small but finite compared to that of the electrolyte electro-osmotically and electrophoretically in water through the micro-channel junc- tion in Fig. 1

Chang, Hsueh-Chia

387

ON A PHASE-FIELD MODEL FOR ELECTROWETTING AND OTHER ELECTROKINETIC PHENOMENA  

E-print Network

electrowetting with electrolytes. The model is thermody- namically consistent. It combines Navier-Stokes and Cahn and are called electrolytes. In response to applied electric fields, they begin to move and induce fluid flow. This is one reason for the importance of electrokinetic phenomena in microfluidics where they are used

Gruen, Guenther

388

Measuring the DC electrokinetic coupling coefficient of porous rock samples in the laboratory : A new apparatus  

Microsoft Academic Search

Electro-kinetic properties of rocks allow the generation of an electric potential by the flow of an aqueous fluid through a porous media. The electrical potential is called the streaming potential, and the streaming potential coupling coefficient is the ratio of the generated electric potential to the pressure difference that causes the fluid flow. The streaming potential coupling coefficient for rocks

Emilie Walker; Eric Tardif; Paul Glover; Jean Ruel; Guillaume Lalande; John Hadjigeorgiou

2010-01-01

389

Measuring the DC electrokinetic coupling coefficient of porous rock samples in the laboratory : a new apparatus  

Microsoft Academic Search

Electro-kinetic properties of rocks allow the generation of an electric potential by the flow of an aqueous fluid through a porous media. The electrical potential is called the streaming potential, and the streaming potential coupling coefficient Cs is the ratio of the generated electric potential to the pressure difference that causes the fluid flow. The streaming potential coupling coefficient for

E. Walker; E. Tardif; P. W. Glover; J. Ruel; J. Hadjigeorgiou

2009-01-01

390

Combination of Electrokinetic Separation and Electrochemical Oxidation for Acid Dye Removal from Soil  

Microsoft Academic Search

The remediation of kaolin soil contaminated with Acid Blue 25 was performed by a combination of electrokinetic separation and electrochemical degradation. The anionic dye was removed from the soil mainly by electroosmosis towards the cathode, with up to 89% removal being achieved at 30 mA for 7 days. The dye solution was completely mineralized in a separate electrochemical oxidation process using

You-Jin Lee; Hyoyeol Han; Seong-Hye Kim; Ji-Won Yang

2009-01-01

391

Numerical Simulation of Electrokinetic Flow and Heat Transfer in Microchannels with a Finite-Volume Method  

Microsoft Academic Search

In this article, electrokinetic flow in rectangular microchannels is studied numerically with a finite-volume method. An externally applied electric field generates varying electromagnetic forces on the fluid, which can be manipulated to control heat exchange and fluid acceleration within the microchannel. Convective heat transfer is predicted on a staggered grid with a finite-volume formulation. The electromagnetic force is modeled as

P. S. Glockner; G. F. Naterer

2006-01-01

392

Electrokinetic methods for arthroscopic detection of cartilage degeneration in synovial joints  

Microsoft Academic Search

This study focuses on two approaches for the nondestructive measurement of certain electrokinetic properties of articular cartilage that provide a sensitive measure of tissue degradation in degenerative joint diseases such as osteoarthritis. The first method involves measurement of current generated stress (electrical to mechanical transduction) using a newly developed surface probe to apply a standing wave of electric current to

S. I. Berkenblit; E. H. Frank; L. J. Bonassar; D. L. Bombard; N. J. Duffin; A. J. Grodzinsky

1994-01-01

393

Selective and quantitative analysis of 4-hydroxybenzoate preservatives by microemulsion electrokinetic chromatography  

Microsoft Academic Search

A microemulsion electrokinetic chromatography (MEEKC) method has been developed and validated for the determination of 4-hydroxybenzoates and their impurities. These materials are commonly known as parabens and are widely used as preservatives in foods, cosmetics and pharmaceuticals. The method was shown to be selective and quantitative for the methyl, ethyl, propyl and butyl esters of 4-hydroxybenzoic acid. An internal standard,

P.-E. Mahuzier; K. D. Altria; B. J. Clark

2001-01-01

394

Pulsed Electrokinetic Decontamination of Agricultural Lands around Abandoned Mines Contaminated with Heavy Metals  

Microsoft Academic Search

The feasibility of pulsed electrokinetic remediation under laboratory conditions was investigated using soil samples from contaminated agricultural land around an abandoned area. The major contaminants of the soil were zinc and cadmium. Sequential extraction showed that most heavy metals existed as strongly bound residual fractions, meaning that they were very difficult to remove. Based upon the overall removal of the

Byung-Gon Ryu; Sung-Woo Park; Kitae Baek; Jung-Seok Yang

2009-01-01

395

SITE TECHNOLOGY CAPSULE; IN SITU ELECTROKINETIC EXTRACTION SYSTEM (EPA/540/R-97/509A)  

EPA Science Inventory

As a part of the Superfund Innovative Technology Evaluation (SITE) Program, the U.S. Environmental Protection Agency evaluated the In-Situ Electrokinetic Extraction (ISEE) system at Sandia National Laboratories, Albuquerque, New Mexico. The SITE demonstration results show that t...

396

Residence time distribution for electrokinetic flow through a microchannel comprising a bundle of cylinders  

Microsoft Academic Search

The electrokinetic flow of an electrolyte solution through a microchannel that comprises a bundle of cylinders is investigated for the case of constant surface potential. The system under consideration is simulated by a unit cell model, and analytical expressions for the flow field and the corresponding residence time distribution under various conditions are derived. These results are readily applicable to

Jyh-Ping Hsu; Chung-Chieh Ting; Duu-Jong Lee; Shiojenn Tseng; Chur-Jen Chen; Ay Su

2007-01-01

397

Effects of sodium incorporation in Co-evaporated Cu2ZnSnSe4 thin-film solar cells  

NASA Astrophysics Data System (ADS)

Sodium incorporation into Cu2ZnSnSe4 (CZTSe) substantially improves the device efficiency by enhancing the open-circuit voltage (VOC) and fill factor. Sodium increases hole density, makes the acceptor shallower, shifts the Fermi level lower, and leads to higher built-in voltage and, consequently, higher VOC. Sodium reduces the concentration of certain deep recombination centers, which further benefits VOC. The increase of hole density and mobility enhances the CZTSe conductivity leading to higher fill factor. Sodium causes smaller depletion width, hence, lower short-circuit current. The minority-carrier lifetime decreases slightly after sodium is incorporated via the Mo-coated soda-lime glass, although adding NaF provides some amelioration.

Li, Jian V.; Kuciauskas, Darius; Young, Matthew R.; Repins, Ingrid L.

2013-04-01

398

Study on Effect of Incorporation of Gelatin Fiber in Jute Fabrics-Reinforced Linear Low Density Polyethylene Composite  

Microsoft Academic Search

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

Bapi Sarker; Ruhul A. Khan

2011-01-01

399

Analysis of trap effect on reliability using the charge pumping technology in La-incorporated high-k dielectrics  

Microsoft Academic Search

In this paper, reliability characteristics of nMOSFETs with La-incorporated HfSiON and HfON and metal gate have been studied. HfLaSiON shows greater device degradation by hot carrier (HC) stress than by positive bias temperature (PBT) stress, while HfLaON exhibits similar degradation during HC stress and PBT stress. To evaluate the contribution of bulk trap during PBT stress, a novel charge pumping

Hyuk-Min Kwon; Won-Ho Choi; In-Shik Han; Sang-Uk Park; Byoung-Seok Park; Ying-Ying Zhang; Chang-Yong Kang; Byoung-Hun Lee; Raj Jammy; Hi-Deok Lee

2010-01-01

400

Effects of elemental composition on the incorporation of dietary nitrogen and carbon isotopic signatures in an omnivorous songbird  

Microsoft Academic Search

The use of stable isotopes to infer diet requires quantifying the relationship between diet and tissues and, in particular, knowing of how quickly isotopes turnover in different tissues and how isotopic concentrations of different food components change (discriminate) when incorporated into consumer tissues. We used feeding trials with wild-caught yellow-rumped warblers (Dendroica coronata) to determine ⤓N and ⤑C turnover rates

Scott F. Pearson; Douglas J. Levey; Cathryn H. Greenberg; Carlos Martínez del Rio; Greenberg; H. Catheryn

2003-01-01

401

Control-Volume Model for Simulation of Water Injection in Fractured Media: Incorporating Matrix Heterogeneity and Reservoir Wettability Effects  

Microsoft Academic Search

Summary The control-volume discrete-fracture (CVDF) model is extended to incorporate heterogeneity in rock and in rock-fluid properties. A novel algorithm is proposed to model strong water-wetting with zero capillary pressure in the fractures. The extended method is used to simulate: (1) oil production in a layered faulted reservoir, (2) laboratory displacement tests in a stack of matrix blocks with a

Jorge Monteagudo; Abbas Firoozabadi

2007-01-01

402

Effect of incorporation of 2-tert-butylaminoethyl methacrylate on flexural strength of a denture base acrylic resin  

PubMed Central

Polymethyl methacrylate (PMMA) resins have commonly been used as a denture base material. However, denture bases may act as a reservoir for microorganisms and contribute to oral diseases in denture wearers. It is hypothesized that the 2-tertbutylaminoethyl methacrylate (TBAEMA) incorporated to acrylic resins should have antimicrobial activity related to the presence of amino groups on acrylic resin surface. Objectives The objectives of this study were to evaluate the presence of amino groups on acrylic resin surface and the influence on flexural strength after incorporation of TBAEMA. Material and Methods Six groups were divided according to the concentration of TBAEMA incorporated to acrylic resin (Lucitone 550): 0, 0.5, 1.0, 1.5, 1.75 and 2%. Specimens surface were evaluated by electron Spectroscopy for Chemical Analysis (ESCA) to detect the presence of amino groups, represented by nitrogen ratios. Flexural strength of the specimens was tested and results were analyzed by ANOVA and Tukey's test (?=0.05). Results Different nitrogen ratios were observed on specimen surfaces: 0, 0.13, 0.74, 0.66, 0.92 and 0.33% for groups 0, 0.5, 1.0, 1.5, 1.75, and 2%, respectively. Significant differences were found for flexural strength (p<0.001). The mean flexural strength values were 98.3±3.9, 93.3±3.2, 83.9±2.1, 82.8±5.2, 71.2±5.1 and 17.3±3.2 MPa for groups 0, 0.5, 1.0, 1.5, 1.75, and 2%, respectively. Conclusion Within the limitations of this study, the incorporation of TBAEMA results in the presence of the potentially antimicrobial amino groups on specimen surfaces, but affect the flexural strength, depending on the concentration of TBAEMA. PMID:21625732

PALEARI, André Gustavo; MARRA, Juliê; PERO, Ana Carolina; RODRIGUEZ, Larissa Santana; RUVOLO-FILHO, Adhemar; COMPAGNONI, Marco Antonio

2011-01-01

403

Electrokinetically enhanced flow and dewatering characteristics of concentrated black coal-water suspensions in pipes  

SciTech Connect

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.

Rozakeas, P.K.; Snow, R.J. [Royal Melbourne Inst. of Technology, Victoria (Australia)

1997-07-01

404

Water oxidation catalysis: effects of nickel incorporation on the structural and chemical properties of the ?-Fe?O?(0001) surface.  

PubMed

Photoelectrochemical solar fuel synthesis devices based on photoactive hematite (?-Fe2O3) anodes have been extensively investigated, yet a fundamental understanding regarding its associated water oxidation surface reaction mechanism is still lacking. To help elucidate detailed reaction mechanisms, we studied water chemisorption and reaction as well as structural changes induced by Ni incorporation into the ?-Fe2O3(0001) surface. Investigation by scanning probe and electron diffraction techniques show that vapor deposition of Ni and subsequent annealing to 700 K leads to the interdiffusion and incorporation of Ni into the near-surface region of hematite and changes the structure of the (0001) surface by the formation of FeO-like domains on the topmost layer. These results are discussed in the context of a proposed water oxidation mechanism on this surface in which Ni doping facilitates water oxidation by increasing O hole concentrations and forms less negatively charged O anions (*O) and *O···OH species [ Liao, P. L.; Keith, J. A.; Carter, E. A. J. Am. Chem. Soc. 2012 , 134 , 13296 - 13309 . ]. Consistent with predictions from this theory, electrochemical measurements using cyclic voltammetry carried out on the ultrahigh vacuum-prepared surfaces demonstrated that Ni incorporation leads to higher current density and lower onset potential than the unmodified ?-Fe2O3 surface. Our work utilizing a surface science approach helps to connect such theoretical predictions of reaction thermodynamics on well-defined structures and the performance of modified hematite model electrocatalysts for water oxidation. PMID:25423044

Zhao, Peng; Koel, Bruce E

2014-12-24

405

[Effect of various xenobiotics on the in vivo incorporation of 14C-acetate into cholesterol and other lipids in the rat].  

PubMed

Effects of some xenobiotics on the incorporation in vivo of [14C]-acetate into cholesterol and other lipids of the rat DDT, HCH, polychlorinated biphenyl, chlorcholine chloride, ethylenthiourea and mixtures of these substances were given to rats with the feed for 7 days. After that the incorporation of [14C]-acetate into phospholipids, triglycerides and cholesterol was studied in liver, serum, heart and brain. The influence of the xenobiotics on the synthesis, transport and accumulation differed among the various organs and lipids. Outstanding was an increase of 14C-phospholipids, -triglycerides and -cholesterol in the heart after administration of polychlorinated biphenyl. The effects in the peripheral organs were generally more distinct than on the liver. PMID:6173977

Seidler, H; Härtig, M; Koslowski, C; Ackermann, H

1981-01-01

406

Randomized Controlled Trial Examining the Effects of Fish Oil and Multivitamin Supplementation on the Incorporation of n-3 and n-6 Fatty Acids into Red Blood Cells  

PubMed Central

The present randomized, placebo-controlled, double-blind, parallel-groups clinical trial examined the effects of fish oil and multivitamin supplementation on the incorporation of n-3 and n-6 fatty acids into red blood cells. Healthy adult humans (n = 160) were randomized to receive 6 g of fish oil, 6 g of fish oil plus a multivitamin, 3 g of fish oil plus a multivitamin or a placebo daily for 16 weeks. Treatment with 6 g of fish oil, with or without a daily multivitamin, led to higher eicosapentaenoic acid (EPA) composition at endpoint. Docosahexaenoic acid (DHA) composition was unchanged following treatment. The long chain LC n-3 PUFA index was only higher, compared to placebo, in the group receiving the combination of 6 g of fish oil and the multivitamin. Analysis by gender revealed that all treatments increased EPA incorporation in females while, in males, EPA was only significantly increased by the 6 g fish oil multivitamin combination. There was considerable individual variability in the red blood cell incorporation of EPA and DHA at endpoint. Gender contributed to a large proportion of this variability with females generally showing higher LC n-3 PUFA composition at endpoint. In conclusion, the incorporation of LC n-3 PUFA into red blood cells was influenced by dosage, the concurrent intake of vitamin/minerals and gender. PMID:24830830

Pipingas, Andrew; Cockerell, Robyn; Grima, Natalie; Sinclair, Andrew; Stough, Con; Scholey, Andrew; Myers, Stephen; Croft, Kevin; Sali, Avni; Pase, Matthew P.

2014-01-01

407

Effects of incorporated alkali metal ions on the chemical bonding states and optical properties in Sr2SiO4:Sm3+ phosphors  

NASA Astrophysics Data System (ADS)

The effects of incorporated alkali metal ions on the chemical bonding states and optical properties in samarium-doped strontium orthosilicate phosphors are studied. Sr2- x M x SiO4:Sm3+ (M = Li, Na, and K) phosphors are synthesized by using tje solid-state reaction method to vary the incorporated amount of the alkali metal ions. The structures, surface morphology, and chemical bonding states of the powders are analyzed. Optical properties for varying amounts of incorporated alkali metal ions are examined by measuring absorption, excitation, and emission spectra. A red-orange emission due to the transition of Sm3+ is observed in all samples, and powders with alkali metal ions incorporated exhibit enhanced emission intensities by a factor of 1.24 to 2.16 compared with that of z pure Sr2SiO4:Sm3+ powder with the same amount of Sm3+. We have shown that Sr2- x M x SiO4:Sm3+ ceramics exhibit a red-orange emission with enhanced intensity for operation with near ultra-violet excitation.

Ha, Myoung Gyu; Han, Kyoung-Rim; Kim, Ju Sung; Bae, Yu Ri; Kim, Jong Pil; Bae, Jong Seong; Hong, K. S.; Yang, Ho-Soon

2014-02-01

408

Randomized controlled trial examining the effects of fish oil and multivitamin supplementation on the incorporation of n-3 and n-6 fatty acids into red blood cells.  

PubMed

The present randomized, placebo-controlled, double-blind, parallel-groups clinical trial examined the effects of fish oil and multivitamin supplementation on the incorporation of n-3 and n-6 fatty acids into red blood cells. Healthy adult humans (n = 160) were randomized to receive 6 g of fish oil, 6 g of fish oil plus a multivitamin, 3 g of fish oil plus a multivitamin or a placebo daily for 16 weeks. Treatment with 6 g of fish oil, with or without a daily multivitamin, led to higher eicosapentaenoic acid (EPA) composition at endpoint. Docosahexaenoic acid (DHA) composition was unchanged following treatment. The long chain LC n-3 PUFA index was only higher, compared to placebo, in the group receiving the combination of 6 g of fish oil and the multivitamin. Analysis by gender revealed that all treatments increased EPA incorporation in females while, in males, EPA was only significantly increased by the 6 g fish oil multivitamin combination. There was considerable individual variability in the red blood cell incorporation of EPA and DHA at endpoint. Gender contributed to a large proportion of this variability with females generally showing higher LC n-3 PUFA composition at endpoint. In conclusion, the incorporation of LC n-3 PUFA into red blood cells was influenced by dosage, the concurrent intake of vitamin/minerals and gender. PMID:24830830

Pipingas, Andrew; Cockerell, Robyn; Grima, Natalie; Sinclair, Andrew; Stough, Con; Scholey, Andrew; Myers, Stephen; Croft, Kevin; Sali, Avni; Pase, Matthew P

2014-05-01

409

Effects of cysteamine administration on the in vivo incorporation of (/sup 35/S)cysteine into somatostatin-14, somatostatin-28, arginine vasopressin, and oxytocin in rat hypothalamus  

SciTech Connect

The effect of cysteamine injection on the in vivo incorporation of (/sup 35/S)cysteine into somatostatin-14 (SRIF-14), SRIF-28, arginine vasopressin (AVP), and oxytocin (OXT) in rat hypothalamus was studied. (/sup 35/S)Cysteine was injected into the third ventricle 1 h, 4 h, or 1 week after cysteamine (300 mg/kg, sc) injection; animals were killed 4 h later. The drug was found to substantially reduce immunoreactive SRIF levels, but not OXT or AVP, 4 h after its injection. Cysteamine also caused large reductions in label incorporation into SRIF-14, SRIF-28, and OXT 1 and 4 h after drug injection. However, (/sup 35/S)cysteine incorporation into AVP was increased substantially at these time points, while that into acid-precipitable protein was normal. One week after cysteamine injection, label incorporation into all hypothalamic peptides was normal. Cysteine specific activity was also measured after (/sup 35/S)cysteine injection and was found to be similar in treatment and control groups. The results suggest that cysteamine inhibits the syntheses of SRIF-14, SRIF-28, and OXT and stimulates that of AVP.

Cameron, J.L.; Fernstrom, J.D.

1986-09-01

410

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)

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.

Li, Yong; Wang, Xiao Bo; Tian, Yong Tao; Li, Xin Jian

2014-11-01

411

Effect of ultraviolet radiation exposure on room-temperature hydrogen sensitivity of nanocrystalline doped tin oxide sensor incorporated into microelectromechanical systems device  

Microsoft Academic Search

The effect of ultraviolet (UV) radiation exposure on the room-temperature hydrogen (H2) sensitivity of nanocrystalline indium oxide (In2O3)-doped tin oxide (SnO2) 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

Satyajit Shukla; Rajnikant Agrawal; Hyoung J. Cho; Sudipta Seal; Lawrence Ludwig; Clyde Parish

2005-01-01

412

Unusual synergistic effects upon incorporation of Fe and/or Ni into mesoporous Co3O4 for enhanced oxygen evolution.  

PubMed

Fe and Ni doped mesoporous Co3O4 (mCo3O4) catalysts were prepared and investigated for electrochemical oxygen evolution. The incorporation of Fe into mCo3O4 (Fe-mCo3O4) results in unusual synergistic effects via destruction of the bulk mesoporous structure and formation of slit-like pores. The Fe-mCo3O4 composite displayed a significantly enhanced catalytic activity for oxygen evolution. PMID:25050969

Xiao, Changlong; Lu, Xunyu; Zhao, Chuan

2014-09-11

413

Correlation of the Capacity Factor in Vesicular Electrokinetic Chromatography with the Octanol: Water Partition Coefficient for Charged and Neutral Analytes  

Microsoft Academic Search

Purpose. The aim of this study was to develop a method based upon electrokinetic chromatography (EKC) using oppositely charged surfactant vesicles as a buffer modifier to estimate hydrophobicity (log P) for a range of neutral and charged compounds.

J. L. Razak; B. J. Cutak; C. K. Larive; C. E. Lunte

2001-01-01

414

Evaluation of newly synthesized and commercially available charged cyclomaltooligosaccharides (cyclodextrins) for capillary electrokinetic chromatography.  

PubMed

A highly new charged cyclodextrin (CD) derivatives, (6-O-carboxymethyl-2,3-di-O-methyl)cyclomaltoheptaoses (CDM-beta-CDs), was synthesized and characterized as anionic reagents for capillary electrophoresis (CE) in an electrokinetic chromatography mode of separation. Substitution with dimethyl groups at the secondary hydroxyl sites of the CD is aimed at influencing the magnitude and selectivity of analyte-CD interactions, while substitution by carboxymethyl groups at the primary hydroxyl sites provides for high charge and electrophoretic mobility. Full regioselective methylation at the secondary hydroxyl sites was achieved in this work, while substitution at the primary hydroxyl sites generated a mixture of multiply charged products. The separation performance of CDM-beta-CD was evaluated using a variety of analyte mixtures. The results obtained from commercially available negatively charged cyclodextrins, heptakis(2,3-di-O-methyl-6-O-sulfo)cyclomaltoheptaose (HDMS-beta-CD) and O-(carboxymethyl)cyclomaltoheptaose (CM-beta-CD) with an average degree of substitution one (DS 1), were compared to CDM-beta-CD using a sample composed of eight positional isomers of dihydroxynaphthalene. Four hydroxylated polychlorobiphenyl derivatives, a group of chiral and isomeric catchecins, and chiral binaphthyl compounds were also separated with CDM-beta-CD. The effect of adding neutral beta-cyclodextrin (beta-CD) into the running buffer containing charged cyclodextrins was investigated and provided evidence of significant inter-CD interactions. Under certain running buffer conditions, the charged cyclodextrins also appear to adsorb to the capillary walls to various degrees. PMID:14698882

Culha, Mustafa; Schell, Fred M; Fox, Shannon; Green, Thomas; Betts, Thomas; Sepaniak, Michael J

2004-01-22

415

AC electrokinetics-enhanced capacitive immunosensor for point-of-care serodiagnosis of infectious diseases.  

PubMed

The current serological diagnostic method can be time consuming and labor intensive, which is not practical for on-site diagnosis and screening of infectious diseases. Capacitive bioaffinity detection using microelectrodes is considered as a promising label-free method for point-of-care diagnosis, though with challenges in sensitivity and the time "from sample to result." With recent development in AC electrokinetics (ACEK), especially in dielectrophoresis (DEP), we are able to develop an ACEK enhanced capacitive bioaffinity sensing method to realize simple, fast and sensitive diagnosis from serum samples. The capacitive immunosensor presented here employs elevated AC potentials at a fixed frequency for impedimetric interrogation of the microelectrodes. According to prior work, such an AC signal is capable of inducing dielectrophoresis and other ACEK effects, so as to realize in-situ enrichment of macromolecules at microelectrodes and hence accelerated detection. Experimental study of the ACEK-enhanced capacitive sensing method was conducted, and the results corroborate our hypothesis. The capacitive sensing responses showed clear frequency dependence and voltage-level dependency, which supports the hypothesis that ACEK aids the antigen-antibody binding, and these dependencies were used to optimize our detection protocol. Our capacitive sensing method was shown to work with bovine sera to differentiate disease-positive samples from negative samples within 2 min, while conventional immunoassay would require multiple processing steps and take hours to complete. The results showed high accuracy and sensitivity. The detection limit is found to reach 10 ng/ml in 2 min. The ACEK-enhanced capacitive immunosensor is a platform technology, and can be employed to detect any combination of probe (e.g. antigen) and analyte (e.g. serum antibody) in a small volume of bodily fluids. PMID:24007749

Li, Shanshan; Cui, Haochen; Yuan, Quan; Wu, Jie; Wadhwa, Ashutosh; Eda, Shigetoshi; Jiang, Hongyuan

2014-01-15

416

Silver(I)-mediated separations by capillary zone electrophoresis and micellar electrokinetic chromatography: argentation electrophoresis.  

PubMed

The addition of Ag(I) to the run buffer in capillary zone electrophoresis (CZE) and micellar electrokinetic chromatography (MEKC), containing sodium dodecyl sulfate, applies the principles of argentation chromatography to electrophoretic separations and is termed "argentation electrophoresis". This technique is shown to provide a complementary method to CZE and MEKC for the separation of specific types of solutes that selectively complex with Ag(I). Baseline resolution in the CZE separation of nine sulfonamides is achieved by the addition of 50 mM silver nitrate to the run buffer. Retention mechanisms in MEKC separations can also be manipulated by the addition of Ag(I) to the micellar solution. Only slight resolution of a pair of sulfonamides was achieved under normal MEKC conditions. Upon the addition of Ag(I) to the mobile phase containing SDS micelles, baseline resolution of the compounds is shown. The retention order and resolution of five sulfonamides changed significantly when 25 mM Ag(I) was added to the SDS-containing buffer. The use of Ag(I) addition in MEKC is also applied to the separation of various other compounds that show selectivity toward Ag(I) complexation, including S-containing heterocycles and vitamin D compounds. The effect of the addition of Ag(I) on the elution range in MEKC is also investigated. A steady increase in the elution range is seen upon increasing the concentration of Ag(I). With a constant percentage of organic modifier (15%), the addition of higher concentrations of silver nitrate (25-50 mM) results in elution ranges greater than 12. The results using Ag(I) as buffer additives in MEKC are also compared to studies utilizing a mixed counterion surfactant of sodium/silver dodecyl sulfate. PMID:8712354

Wright, P B; Dorsey, J G

1996-02-01

417

Determination of 5-nitroimidazoles and metabolites in environmental samples by micellar electrokinetic chromatography.  

PubMed

A method based on micellar electrokinetic chromatography (MEKC) with UV detection has been developed for the determination of nine 5-nitroimidazoles (5-NDZs), including metabolites in river water samples. Due to the relative insensitivity of UV detection in MEKC, a solid-phase extraction (SPE) method has been proposed that preconcentrates water samples fiftyfold and cleans them up off-line. An on-line preconcentration approach based on sweeping and the use of an extended light path fused-silica capillary (64.5 cm?×?50 ?m i.d., 56 cm effective length) was also found to improve the sensitivity of the method. Separation was carried out in <21 min using 20 mM phosphate buffer (pH 6.5) and 150 mM SDS as the background electrolyte (BGE). The temperature of the capillary was kept constant at 20°C, a voltage of 25 kV was applied (normal mode), and a detected wavelength of 320 nm was utilized. Hydrodynamic injection (50 mbar for 15 s) of the samples, which were dissolved in 20 mM phosphate (pH 6.5), was employed. The limits of detection were lower than 1.1 ?g L(-1). Recoveries of >80% from spiked river water samples were obtained for most of the analytes at three different concentration levels with acceptable precision. This method could provide an efficient and economical alternative to the use of chromatographic methods to monitor nitroimidazole residues, thus supplementing the relatively few methods available for the analysis of these compounds in environmental samples. PMID:22434275

Hernández-Mesa, Maykel; Cruces-Blanco, Carmen; García-Campaña, Ana M

2012-08-01

418

Electrokinetic Studies on Emulsions Stabilized by Ionic Surfactants: The Electroacoustophoretic Behavior and Estimation of Davies’ HLB Increments  

Microsoft Academic Search

Model oil-in-water emulsions were made. To stabilize these emulsions ionic surfactants were added. Their electrokinetic behavior was studied applying the electroacoustophoresis technique. The so-called electrokinetic sonic amplitude (ESA) was determined as a function of ionic strength, pH, and concentration and type of surfactant at ambient temperature and pressure. More than 30 different types of surfactant, mainly cationics, were included. Ionic

O Boen Ho

1998-01-01

419

Effect of a smartphone application incorporating personalized health-related imagery on adherence to antiretroviral therapy: a randomized clinical trial.  

PubMed

Poor adherence to combination antiretroviral therapy (ART) is a major global challenge. In this study we examined the efficacy of a smartphone application incorporating personalized health-related visual imagery that provided real-time information about the level of medication and the patient's level of immunoprotection, in order to improve adherence to ART. We randomized 28 people on ART to either a standard or augmented version of the smartphone application. The augmented version contained components that illustrated participants' current estimated plasma concentrations of antiretroviral drugs and the immune protection provided by ART. Adherence to ART was assessed at baseline and at 3 months using self-reported adherence, pharmacy dispensing records, and HIV viral load. Information was also collected on illness and medication beliefs and use of the application. Participants who received the augmented application showed a significantly higher level of self-reported adherence to ART at 3 months (p=0.03) and decreased viral load (p=0.023) as compared to individuals using the standard version. Greater usage of the extra components of the augmented application was associated with greater perceived understanding of HIV infection and increased perceived necessity for ART. Smartphone applications that incorporate personalized health-related visual imagery may have potential to improve adherence to ART. PMID:25290556

Perera, Anna I; Thomas, Mark G; Moore, John O; Faasse, Kate; Petrie, Keith J

2014-11-01

420

Evaluation of sintering effects on SiC incorporated UO2 kernels under Ar and Ar-4%H2 environments  

SciTech Connect

Silicon carbide (SiC) is suggested as an oxygen getter in UO2 kernels used for TRISO particle fuels to lower oxygen potential and prevent kernel migration during irradiation. Scanning electron microscopy and X-ray diffractometry analyses performed on sintered kernels verified that internal gelation process can be used to incorporate SiC in urania fuel kernels. Sintering in either Ar or Ar-4%H2 at 1500 C lowered the SiC content in the UO2 kernels to some extent. Formation of UC was observed as the major chemical phase in the process, while other minor phases such as U3Si2C2, USi2, U3Si2, and UC2 were also identified. UC formation was presumed to be occurred by two reactions. The first was the SiC reaction with its protective SiO2 oxide layer on SiC grains to produce volatile SiO and free carbon that subsequently reacted with UO2 to form UC. The second process was direct UO2 reaction with SiC grains to form SiO, CO, and UC, especially in Ar-4%H2. A slightly higher density and UC content was observed in the sample sintered in Ar-4%H2, but the use of both atmospheres produced kernels with ~95% of theoretical density. It is suggested that incorporating CO in the sintering gas would prevent UC formation and preserve the initial SiC content.

Silva, Chinthaka M [ORNL] [ORNL; Lindemer, Terrence [Harbach Engineering and Solutions] [Harbach Engineering and Solutions; Hunt, Rodney Dale [ORNL] [ORNL; Collins, Jack Lee [ORNL] [ORNL; Terrani, Kurt A [ORNL] [ORNL; Snead, Lance Lewis [ORNL] [ORNL

2013-01-01