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1

Electrokinetic effects on detection time of nanowire biosensor  

PubMed Central

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. PMID:22550358

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

2012-01-01

2

Joule heating effects on electrokinetic focusing and trapping of particles in constriction microchannels  

E-print Network

Joule heating effects on electrokinetic focusing and trapping of particles in constriction.1088/0960-1317/22/7/075011 Joule heating effects on electrokinetic focusing and trapping of particles in constriction microchannels.iop.org/JMM/22/075011 Abstract Joule heating (JH) is a ubiquitous phenomenon in electrokinetic microfluidic

Xuan, Xiangchun "Schwann"

3

Modeling forced liquid convection in rectangular microchannels with electrokinetic effects  

Microsoft Academic Search

The effects of the electric double layer near the solid–liquid interface and the flow induced electrokinetic field on the pressure-driven flow and heat transfer through a rectangular microchannel are analyzed in this work. The electric double layer field in the cross-section of rectangular microchannels is determined by solving a non-linear, two-dimensional Poisson–Boltzmann equation. A body force caused by the electric

Chun Yang; Dongqing Li; Jacob H. Masliyah

1998-01-01

4

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

E-print Network

Analytical and Numerical Study of Joule Heating Effects on Electrokinetically Pumped Continuous Form: December 8, 2007 Joule heating is an inevitable phenomenon for microfluidic chips involving been established and solved using the Green's function for evaluating Joule heating effects

Le Roy, Robert J.

5

Electrokinetics of suspended charged particles taking into account the excluded volume effect.  

PubMed

In two recent works [López-García et al., J. Colloid Interface Sci. 316 (2007) 196; López-García et al., J. Colloid Interface Sci. 323 (2008) 146] we presented a simple modification of the standard electrokinetic model that takes into account the finite size of ions in the electrolyte solution. In the first we presented numerical results for the equilibrium properties while, in the second, we calculated the effect of the excluded ion volume on the electrophoretic mobility. In the present work we first extend our previous results incorporating a distance of closest approach of the ions to the particle surface. We then calculate the conductivity increment and present a detailed interpretation of the mobility and conductivity increment results, based on the analysis of the equilibrium and field-induced ion concentrations and of the convective fluid flow in the neighborhood of the particle surface. We show that the inclusion of the ion size effect generally improves the predictions of the standard electrokinetic model: both the electrophoretic mobility and the conductivity increment increase. We also show that, largely due to the above-noted extension of considering a minimum approach distance between the ions and the particle surface, the excluded volume effect is not negligible even for weakly charged particles. PMID:19427641

Aranda-Rascón, M J; Grosse, C; López-García, J J; Horno, J

2009-07-15

6

Electrokinetic effects at the edge of silicon supported solid state nanopore membranes  

NASA Astrophysics Data System (ADS)

The core motivation of research toward the use of nanopores as electrochemical transducers for genomic sequencing is the potential for rapid sequencing of minimally and inexpensively prepared nucleic acids of great length. Towards this, solid state nanopore arrays are anticipated to be incorporated in the completed solution because of their ability to parallelize the sequencing process resulting in extremely high throughput. Here we experimentally and numerically analyze the electrokinetic effects at the edge of the commonly used silicon supported solid state free standing membrane as a function of membrane chip's material properties and geometry. Experimentally we show regions of localized flow circulation near the edge of the freestanding membrane under commonly used DNA translocation experimental conditions. We investigate the circulation regions through numerical electrohydrodynamic flow simulation and postulate on its possible effect on long strand DNA experiments.

Mulero, Rafael; Robiul Hossan, Mohammad; Dutta, Prashanta; Kim, Minjun

2010-03-01

7

Electrokinetically controlled real-time polymerase chain reaction in microchannel using Joule heating effect  

Microsoft Academic Search

In this work, a new method to control polymerase chain reaction (PCR) thermal cycling in a microchannel using Joule heating effect was presented. Joule heating was generated internally by the current flow through the buffer solution in an electrokinetically-driven microfluidic chip without external heater component. Numerical simulations were developed and conducted to determine the parameters required to achieve the desired

Guoqing Hu; Qing Xiang; Rachel Fu; Bo Xu; Roberto Venditti; Dongqing Li

2006-01-01

8

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

9

Electrokinetic decontamination of concrete  

SciTech Connect

ELECTROSORB Electrokinetic Extraction Technology, developed by ISOTRON Corp., offers a cost-effective approach to treating contaminated concrete. Heavy metals/radionuclides trapped in concrete can be extracted using this process if they are chemically solubilized; solubilizers used are citric acid alone and a mixture of citric and nitric acids. A DC electric field is applied across the contaminated concrete to electrokinetically transport the solubilized contaminants from the concrete pores to a collector on the concrete surface. The collector is an extraction pad laid on the surface. The pad provides confinement for a planar electrode and solubilizer solution; it is operated under a vacuum to hold the pad against the concrete surface. Operation requires little attendance, reducing the workers` health hazards. The process incorporates a mechanism for recycling the solubilizer solution. A field demonstration of the process took place in Building 21 of DOE`s Mound facility in Miamisburg, OH, over 12 days in June 1996. The thorium species present in this building`s concrete floors included ThO{sub 2} and thorium oxalate. The nitric acid was found to facilitate Th extraction.

Lomasney, H.L.; SenGupta, A.K.; Yachmenev, V.

1996-12-31

10

pH effects on micelle–water partitioning determined by micellar electrokinetic chromatography  

Microsoft Academic Search

In many biological and environmental situations, the pH of aqueous media varies and differences in solute partitioning may result. However, the majority of biopartitioning and hydrophobicity studies conducted have been at pH 7. Using migration factors measured by micellar electrokinetic chromatography, we have determined pH effects on micelle–water partitioning for 19 compounds. We develop an improvement to the migration factor

David J. Bailey; John G. Dorsey

1999-01-01

11

Effect of clay mineralogy on the feasibility of electrokinetic soil decontamination technology  

Microsoft Academic Search

To evaluate the effect of clay mineralogy on the feasibility of electrokinetic soil remediation technology, we contaminated six soils with Cu(II), Zn(II) and Pb(II) and performed electroremediation for 570 h. Cation exchange resin saturated with H+ was placed between soil and cathode to prevent soil alkalinization and trap the migrated heavy metal cations. After the treatment, the heavy metal cations

S Darmawan; S.-I Wada

2002-01-01

12

Effect of electrokinetic transport on the vulnerability of PAH-degrading bacteria in a model aquifer  

Microsoft Academic Search

There has been increasing interest in employing electro-bioremediation, a hybrid technology of bioremediation and electrokinetics,\\u000a to overcome the low bioavailability of hydrophobic organic contaminants (HOC) by homogenizing sorption-retarded HOC and immobilised\\u000a microorganisms. Present electro-remediation approaches mainly aim at macroscale pollutant extraction and tend to neglect possible\\u000a impacts of direct current (DC) on the physiology of microorganisms. The effect of weak

Lei Shi; Susann Müller; Hauke Harms; Lukas Y. Wick

2008-01-01

13

Electrokinetics of charged spherical colloidal particles taking into account the effect of ion size constraints.  

PubMed

The electrokinetic properties of suspended spherical particles are examined using a modified standard electrokinetic model, which takes into account the finite ion size and considers that the minimum approach distance of ions to the particle surface need not be equal to their effective radius in the bulk solution. We calculate the conductivity increment and the electrophoretic mobility and present a detailed interpretation of the obtained results, based on the analysis of the equilibrium and field-induced ion concentrations, as well as the convective fluid flow in the neighborhood of the particle surface. We show that when charge reversal takes place, the sign of the concentration polarization remains unchanged while the sign of the electrophoretic mobility only changes under favorable circumstances. PMID:21281935

López-García, J J; Aranda-Rascón, M J; Grosse, C; Horno, J

2011-04-01

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

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

16

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

PubMed

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. PMID:22958853

Roa, Rafael; Carrique, Félix; Ruiz-Reina, Emilio

2012-12-01

17

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

2012-03-25

18

DC electrokinetics for spherical particles in salt-free concentrated suspensions including ion size effects  

E-print Network

We study the electrophoretic mobility of spherical particles and the electrical conductivity in salt-free concentrated suspensions including finite ion size effects. An ideal salt-free suspension is composed of just charged colloidal particles and the added counterions that counterbalance their surface charge. In a very recent paper [Roa et al., Phys. Chem. Chem. Phys., 2011, 13, 3960- 3968] we presented a model for the equilibrium electric double layer for this kind of suspensions considering the size of the counterions, and now we extend this work to analyze the response of the suspension under a static external electric field. The numerical results show the high importance of such corrections for moderate to high particle charges, especially when a region of closest approach of the counterions to the particle surface is considered. The present work sets the basis for further theoretical models with finite ion size corrections, concerning particularly the ac electrokinetics and rheology of such systems.

Rafael Roa; Félix Carrique; Emilio Ruiz-Reina

2011-10-31

19

Preliminary results from the investigation of thermal effects in electrokinetics soil remediation  

SciTech Connect

Electrokinetics is an emerging soil remediation technology. Contaminants are extracted from the soil as a result of a complex set of phenomena that occur when an electric gradient is imposed across a soil-water system. The primary phenomena include electroosmosis, electromigration, and electrophoresis. Secondary phenomena, such as changes in solubility or speciation of various chemical components, may occur as a result of electrically induced changes in the chemical environment of the system. Numerous factors, such as temperature, may affect each of these phenomena and, consequently, the overall process efficiency. We have begun an investigation of thermal effects in the extraction of potassium dichromate from kaolinite soils under conditions of constant saturation and dewatering. Preliminary results suggest that increasing the soil temperature from 21 to 55{degrees}C may decrease the processing time under saturated conditions. However, increasing the soil temperature under dewatering, conditions causes soil cracking, which reduces the overall process efficiency.

Krause, T.R.; Tarman, B.

1993-10-01

20

Electrokinetic decontamination of millpond sludge  

SciTech Connect

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

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

1995-12-31

21

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

22

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

PubMed

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

Yu, Meijuan; Hang, Dong; Cao, Yuhua

2011-02-01

23

Electromagnetic field generated by a finite fault due to electrokinetic effect  

NASA Astrophysics Data System (ADS)

This work investigates surface electromagnetic wavefields generated by a finite fault due to electrokinetic effect with Pride's theory as the governing equations. A finite fault is discretized into a series of small subfaults, each of which is taken as a point source with different initiation time. The wavefields generated by the whole fault are then synthesized by stacking those generated by all the subfaults. Numerical simulations of a vertical strike-slip fault with a constant rupturing velocity are then conducted on the basis of the derived formalism. Simulation results show that the rupturing fault generates observable permanent ground motions and electromagnetic field disturbances. Two types of electric field characters are observed in simulations: the coseismic oscillatory variation and the postseismic decaying variation. When the fault rupturing stops and the seismic waves pass far away, the magnetic field vanishes while the electric field remains, decaying slowly and lasting for hundreds of seconds. Adjacent to the free surface the vertical electric field is about 100 times larger than the horizontal one. When the receiving depth increases, the amplitudes of the horizontal electric fields in both the oscillatory and decaying components increase while those of the vertical electric fields decrease. It is also shown that there is no horizontal electric field remnant right at the free surface after the seismic perturbations decay away. The near-fault electric fields simulated in this paper hold similar features to some field observations in literature.

Hu, Hengshan; Gao, Yongxin

2011-08-01

24

Electrokinetics of non-Newtonian fluids: a review.  

PubMed

This work presents a comprehensive review of electrokinetics pertaining to non-Newtonian fluids. The topic covers a broad range of non-Newtonian effects in electrokinetics, including electroosmosis of non-Newtonian fluids, electrophoresis of particles in non-Newtonian fluids, streaming potential effect of non-Newtonian fluids and other related non-Newtonian effects in electrokinetics. Generally, the coupling between non-Newtonian hydrodynamics and electrostatics not only complicates the electrokinetics but also causes the fluid/particle velocity to be nonlinearly dependent on the strength of external electric field and/or the zeta potential. Shear-thinning nature of liquids tends to enhance electrokinetic phenomena, while shear-thickening nature of liquids leads to the reduction of electrokinetic effects. In addition, directions for the future studies are suggested and several theoretical issues in non-Newtonian electrokinetics are highlighted. PMID:24148843

Zhao, Cunlu; Yang, Chun

2013-12-01

25

[Movement-adsorption and its mechanism of Cd in soil under combining effects of electrokinetics and a new type of bamboo charcoal].  

PubMed

The characteristics of migration and its influencing factor of cadmium in sandy loam soil by uniform electrokinetics as well as the adsorption property by a new material-bamboo charcoal were investigated through bench-scale experiments, and the feasibility of using electrokinetic technique combined with the newly developed bamboo charcoal for remediation of cadmium contaminated soils was analyzed as well. The results show that the bamboo charcoal is good adsorption material which has comparably strong adsorption effect on Cd, bearing potential in future use, which could be simulated by both Freundlich and Langmuir models (R2 > 0.96). The migration rates of cadmium in sandy loam were high up to 0. 6786 - 0.6875cm/h under an electric gradient of 1.0V/cm, depending upon the concentration of cadmium and the distribution of electric field density. Electrokinetics effectively transported the heavy metal in the soil. In the new electrokinetic tech combining the bamboo charcoal with the same electric gradient above under the polarity reversal period of 48 hours, the cadmium in the soil could be wiped off with high efficiency (removal efficiency 79.6% in 12 days) and the pH together with water content could be well retained. The electric current in the process changed periodically according to the reversal. As a new technique, the electrokinetic movement-bamboo charcoal adsorption holds high potential in future use. PMID:17926419

Ma, Jian-Wei; Wang, Hui; Luo, Qi-Shi

2007-08-01

26

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

Microsoft Academic Search

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

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

2009-01-01

27

Cationic gemini surfactants as pseudostationary phases in micellar electrokinetic chromatography. Part I: effect of head group.  

PubMed

Two cationic gemini surfactants with pyrrolidinium or alkyl ammonium head groups with but-2-yne spacers, but with the same length hydrocarbon chain have been characterized with respect to their aggregation behaviors and separation power as pseudostationary phases (PSPs) for micellar electrokinetic chromatography (MEKC). They were compared with a commonly used PSP, sodium dodecylsulfate (SDS). The results suggest that the head groups of the surfactants have some effect on physicochemical properties such as critical micelle concentration (CMC), C(20), gamma(CMC), partial specific volume, methylene selectivity and mobilities of the surfactants. CMC values of G1, G2 and SDS in pure water were found to be 0.82, 0.71, and 8.08 mM, respectively; they were reduced to 0.21, 0.11, and 3.0 mM when measured in 10 mM phosphate buffer at pH 7.0. G1 (alphaCH2 = 2.74) and G2 (alphaCH2 = 2.48) provided the most and the least hydrophobic environment, respectively. According to their partial specific volumes, geminis were found to have more flexible structures as compared with sodium dodecylsulfate. The effects of the head group structure were also characterized with the linear solvation energy relationship (LSER) model, which was able to evaluate the role of solute size, polarity/polarizability, and hydrogen bonding on retention and selectivity. The cohesiveness, hydrogen bond acidic and basic character of the surfactant systems were found to have the most significant influence on selectivity and MEKC retention of the gemini surfactants. It should be noted that with their large positive coefficient a values, G1 and G2 were found to be stronger HB acceptors than anionic and most of the cationic surfactants studied in the literature. PMID:20598697

Akbay, Cevdet; Hoyos, Yatzka; Hooper, Edward; Arslan, Hakan; Rizvi, Syed A A

2010-08-01

28

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

29

Numerical analysis of the thermal effect on electroosmotic flow and electrokinetic mass transport in microchannels  

Microsoft Academic Search

Joule heating is present in electrokinetically driven flow and mass transport in microfluidic systems. Nowadays, there is a trend of replacing costly glass-based microfluidic systems by the disposable, cheap polymer-based microfluidic systems. Due to poor thermal conductivity of polymer materials, the thermal management of the polymer-based microfluidic systems may become a problem. In this study, numerical analysis is presented for

G. Y Tang; C Yang; C. K Chai; H. Q Gong

2004-01-01

30

Electrokinetics in undeveloped flows.  

PubMed

For the correct interpretation of results of tangential electrokinetic measurements with porous materials, in particular, composite/asymmetric membranes on porous supports, it is necessary to have the data available for various channel heights. In some kinds of equipment, the variation of channel height is technically possible only for a range of relatively large heights. This communication shows that under these conditions, the fluid flow can become undeveloped and the conventional approaches to the interpretation of electrokinetic measurements should be modified accordingly. In particular, the dependence of streaming-current coefficient on the channel height becomes sub-linear. If the experimental data are available only for larger channel heights, this can be mistakenly taken for the manifestation of contribution of porous sub-structure to the streaming current. In this communication, we investigate electrokinetic phenomena in undeveloped flows both numerically and experimentally. We confirm that the aforementioned sub-linearity occurs for nonporous as well as porous substrates. We also demonstrate that the channel heights estimated from the volume flow rate by using numerical simulations of undeveloped flows are in very good agreement with the reference values obtained from the electrical conductance (in contrast to the values estimated by using the conventional approach of Hagen-Poiseuille equation). The numerical fitting of channel-height dependences of streaming-current coefficient enables us to separate the contributions of external surface and porous sub-structure (in case of porous substrates) and obtain quite reasonable values of (effective) zeta-potentials in both cases. Nonetheless, the accuracy of experimental data deteriorates with increasing channel height, so it is generally advisable to vary the heights within a range below 100-150 ?m. PMID:24034221

Yaroshchuk, Andriy; Bernal, Edxon Eduardo Licón; Luxbacher, Thomas

2013-11-15

31

The effect of redox potential on the electrokinetic remediation of mercury contaminated soils  

SciTech Connect

An electrokinetic process for remediation of mercury contaminated soils using an iodine-iodide lixiviant was developed. In this process, reduced forms of insoluble mercury are oxidized by iodine. Iodide then reacts with mercury to form the highly soluble HgI{sub 4}{sup 2-} complex, which in turn migrates toward the anode via electromigration. The objective was to determine the thermodynamic conditions under which mercury could be solubilized and transported from the soil. At the end of the electrokinetic treatment process, pH, pE, iodine, iodide, and soluble and total mercury were measured along the length of the soil. The process was tested on a soil contaminated with HgS (cinnabar) in the laboratory and a contaminated soil obtained from a hazardous waste site. Up to 99% overall removal of mercury could be achieved from the laboratory contaminated soil. Up to 84% of mercury was removed from some sections of the field contaminated soil, but overall removal was only 6%. The presence of iodine in the soil pore water was found to be the most important factor in solubilization of mercury. Residual levels of soluble Hg remaining in soil after treatment were greater than allowed by current regulations and far in excess of the solubility of Hg compounds present in the untreated soil.

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

1996-12-31

32

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

PubMed

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

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

2014-09-15

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

3-dimensional electrokinetic tweezing  

Microsoft Academic Search

We show how to extend electrokinetic tweezing, which can manipulate any visible particles and has more favorable force scaling than optical actuation enabling manipulation of nanoscale objects to nanoscopic precision, from 2-dimensional control to the third dimension (3D). A novel and practical multi- layer device is presented that can create both planar and vertical flow and electric field modes. Feedback

Roland Probst; Benjamin Shapiro

2011-01-01

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

Electrokinetic Microstrirring to Enhance Immunoassays  

NASA Astrophysics Data System (ADS)

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

Feldman, Hope; Sigurdson, Marin; Meinhart, Carl

2006-11-01

38

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

39

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

40

Influence of current density and pH on electrokinetics  

Microsoft Academic Search

Two series of electrokinetic experiments have been conducted on kaolinite to study the effects of current density and influent pH on electrokinetic processing. In the first series, eleven tests were conducted at different current densities ranging from 0.123 mA\\/cm2 (10 mA) to 0.615 mA\\/cm2 (50 mA) using distilled water as the influent. In the second series, ten tests were conducted

Jihad T. Hamed; Ashish Bhadra

1997-01-01

41

Electrokinetic Properties of Perlite  

Microsoft Academic Search

Electrokinetic properties of expanded and unexpanded perlite samples have been investigated using the microelectrophoresis technique. Perlite samples yield practically no isoelectric point in the pH range of 3 to 11. Both of the perlite samples remain negatively charged in the pH range studied. The expanded perlite has a more negatively charged surface than unexpanded perlite. NaCl, KNO3, NaNO3, Na2CO3, and

Mehmet D?g; Mahir Alkan; Ümit Çakir

1997-01-01

42

Journal of Chromatography A, 1064 (2005) 227237 Analytical study of Joule heating effects on electrokinetic  

E-print Network

Journal of Chromatography A, 1064 (2005) 227­237 Analytical study of Joule heating effects Joule heating when electric currents are passing through electrolyte solutions. Joule heating not only an analytical model to study Joule heating effects on the transport of heat, electricity, momentum and mass

Xuan, Xiangchun "Schwann"

43

Analytical study of Joule heating effects on electrokinetic transportation in capillary electrophoresis  

Microsoft Academic Search

Electric fields are often used to transport fluids (by electroosmosis) and separate charged samples (by electrophoresis) in microfluidic devices. However, there exists inevitable Joule heating when electric currents are passing through electrolyte solutions. Joule heating not only increases the fluid temperature, but also produces temperature gradients in cross-stream and axial directions. These temperature effects make fluid properties non-uniform, and hence

Xiangchun Xuan; Dongqing Li

2005-01-01

44

Analysis of electrokinetic effects on the liquid flow in rectangular microchannels  

Microsoft Academic Search

The effects of the electrical double layer near the solid\\/liquid interface on liquid flow through a rectangular microchannel are analyzed in this work. Based on the Debye–Hückel approximation, a linear solution of a two-dimensional Poisson–Boltzmann equation governing the electrical potential distribution in the cross-section of rectangular channels is presented to describe the electrical double-layer field near the solid\\/liquid interface. An

Chun Yang; Dongqing Li

1998-01-01

45

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

46

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

PubMed

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

Mondal, Sourav; De, Sirshendu

2013-03-01

47

Incorporating tillage effects into a soybean model  

Microsoft Academic Search

Crop growth models can be useful tools in evaluating the impacts of different tillage systems on the growth and final yield of crops. A tillage model was incorporated into CROPGRO-Soybean and tested for conditions in Ames, IA, USA. Predictions of changes in surface residue, bulk density, hydraulic conductivity, runoff curve number, and surface albedo were consistent with expected behaviors of

A. A. Andales; W. D. Batchelor; C. E. Anderson; D. E. Farnham; D. K. Whigham

2000-01-01

48

Mathematical model for hydraulically aided electrokinetic remediation of aquifer and removal of nonanionic copper  

Microsoft Academic Search

One of the most cost-effective in situ technologies for soil and groundwater (i.e., aquifer) remediation is electrokinetic remediation. In electrokinetic remediation, electromigration due to electric field is combined with hydromigration due to hydraulic flow by purge water to remove pollutants from aquifers through the pore water. This study aims at investigating theoretically the role of electromigration (as active movement) of

Sadataka Shiba; Yushi Hirata; Tadachika Seno

2005-01-01

49

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

50

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

51

Tensorial Electrokinetics in Articular Cartilage  

PubMed Central

Electrokinetic phenomena contribute to biomechanical functions of articular cartilage and underlie promising methods for early detection of osteoarthritic lesions. Although some transport properties, such as hydraulic permeability, are known to become anisotropic with compression, the direction-dependence of cartilage electrokinetic properties remains unknown. Electroosmosis experiments were therefore performed on adult bovine articular cartilage samples, whereby fluid flows were driven by electric currents in directions parallel and perpendicular to the articular surface of statically compressed explants. Magnitudes of electrokinetic coefficients decreased slightly with compression (from ??7.5 ?L/As in the range of 0–20% compression to ?6.0 ?L/As in the 35–50% range) consistent with predictions of microstructure-based models of cartilage material properties. However, no significant dependence on direction of the electrokinetic coupling coefficient was detected, even for conditions where the hydraulic permeability tensor is known to be anisotropic. This contrast may also be interpreted using microstructure-based models, and provides insights into structure-function relationships in cartilage extracellular matrix and physical mediators of cell responses to tissue compression. Findings support the use of relatively simple isotropic modeling approaches for electrokinetic phenomena in cartilage and related materials, and indicate that measurement of electrokinetic properties may provide particularly robust means for clinical evaluation of cartilage matrix integrity. PMID:16798804

Reynaud, Boris; Quinn, Thomas M.

2006-01-01

52

Numerical simulation of electrokinetically driven micro flows  

E-print Network

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

Hahm, Jungyoon

2005-11-01

53

Electrokinetics over liquid/liquid interfaces  

NASA Astrophysics Data System (ADS)

Since liquid-liquid interfaces flow in response to an applied stress, one might expect electrokinetic flows at liquid-liquid interfaces to be significantly higher than over liquid-solid interfaces. The earliest predictions for the electrophoretic mobility of charged mercury drops -- distinct approaches by Frumkin and Levich (1946), and Booth (1951) -- differed by O(a/?D), where a is the radius of the drop and ?D is the Debye screening length. Seeking to reconcile this rather striking discrepancy, Levine (1973) showed double-layer polarization to be the key ingredient. Without a physical mechanism by which electrokinetic effects are enhanced, however, it is difficult to know how general the enhancement is -- whether it holds only for liquid metal surfaces, or more generally, for all liquid/liquid surfaces. By considering a series of systems in which a planar metal strip is coated with either a liquid metal or liquid dielectric, we show that the central physical mechanism behind the enhancement predicted by Frumkin and Levich (1946) is the presence of an unmatched electrical stress upon the electrolyte-liquid interface, which establishes a Marangoni stress on the droplet surface and drives it into motion. The source of the unbalanced electrokinetic stress on a liquid metal surface is clear -- metals represent equipotential surfaces, so no field exists to drive an equal and opposite force on the surface charge. This might suggest that liquid metals represent a unique system, since dielectric liquids can support finite electric fields, which might be expected to exert an electrical stress on the surface charge that balances the electric stress. We demonstrate, however, that electrical and osmotic stresses on relaxed double-layers internal to dielectric liquids precisely cancel, so that internal electrokinetic stresses generally vanish in closed, ideally polarizable liquids. The enhancement for liquid mercury drops can thus be expected quite generally over clean, ideally polarizable liquid drops. More broadly, the ability to reliably engineer liquid interfaces in microfluidic systems, then, may provide a path to significantly enhanced electrokinetic flows.

Squires, Todd M.

2011-11-01

54

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

PubMed

Neuronal activity loss may be due to toxicity caused by amyloid-beta peptides forming soluble oligomers. Here amyloid-beta peptides (1-42, 1-40, 1-39, 1-38, and 1-37) are characterized through the modeling of their experimental effective electrophoretic mobilities determined by a capillary zone electrophoresis method as reported in the literature. The resulting electrokinetic and hydrodynamic global properties are used to evaluate amyloid-beta peptide propensities to aggregation through pair particles interaction potentials and Brownian aggregation kinetic theories. Two background electrolytes are considered at 25°C, one for pH 9 and ionic strength I = 40 mM (aggregation is inhibited through NH4 OH) the other for pH 10 and I = 100 mM (without NH4 OH). Physical explanations of peptide oligomerization mechanisms are provided. The effect of hydration, electrostatic, and dispersion forces in the amyloidogenic process of amyloid-beta peptides (1-40 and 1-42) are quantitatively presented. The interplay among effective charge number, hydration, and conformation of chains is described. It is shown that amyloid-beta peptides (1-40 and 1-42) at pH 10, I = 100 mM and 25°C, may form soluble oligomers, mainly of order 2 and 4, after an incubation of 48 h, which at higher times evolve and end up in complex structures (protofibrils and fibrils) found in plaques associated with Alzheimer's disease. PMID:24975363

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

2014-09-01

55

Enhancing Clinical Trials by Incorporating Side Effects  

ERIC Educational Resources Information Center

Evidence-based medicine is often seen as a model for evidence-based education, and deservedly so, but evaluators in education have been slow to adopt one of its salient features, attention to side effects. Many education evaluations focus almost exclusively on efficacy, that is on achievement test scores. Regardless of domain, all interventions…

Schrag, Francis

2009-01-01

56

Acoustically and Electrokinetically Driven Transport in Microfluidic Devices  

NASA Astrophysics Data System (ADS)

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

Sayar, Ersin

57

Electrokinetic remediation of unsaturated soils  

SciTech Connect

Heavy-metal contamination of soil and groundwater is a widespread problem in the DOE weapons complex, and for the nation as a whole electrokinetic remediation is one possible technique for in situ removal of such contaminants from unsaturated soils. Large spills and leaks can contaminate both the soil above the water table as well as the aquifer itself. Electrodes are implanted in the soil, and a direct current is imposed between the electrodes. The application of direct current leads to a number of effects: ionic species and charged particles in the soil water will migrate to the oppositely charged electrode (electromigration and electrophoresis), and concomitant with this migration, a bulk flow of water is induced, usually toward the cathode (electroosmosis). The combination of these phenomena leads to a movement of contaminants toward the electrodes. The direction of contaminant movement will be determined by a number of factors, among which are type and concentration of contaminant, soil type and structure, interfacial chemistry of the soil-water system, and the current density in the soil pore water. Contaminants arriving at the electrodes may potentially be removed from the soil by one of several methods, such as electroplating or adsorption onto the electrode, precipitation or co-precipitation at the electrode, pumping of water near the electrode, or complexing with ion-exchange resins. Experimental results are described on the removal of sodium dichromate and food dye from soil.

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

1992-01-01

58

Electrokinetic remediation of unsaturated soils  

SciTech Connect

Heavy-metal contamination of soil and groundwater is a widespread problem in the DOE weapons complex, and for the nation as a whole electrokinetic remediation is one possible technique for in situ removal of such contaminants from unsaturated soils. Large spills and leaks can contaminate both the soil above the water table as well as the aquifer itself. Electrodes are implanted in the soil, and a direct current is imposed between the electrodes. The application of direct current leads to a number of effects: ionic species and charged particles in the soil water will migrate to the oppositely charged electrode (electromigration and electrophoresis), and concomitant with this migration, a bulk flow of water is induced, usually toward the cathode (electroosmosis). The combination of these phenomena leads to a movement of contaminants toward the electrodes. The direction of contaminant movement will be determined by a number of factors, among which are type and concentration of contaminant, soil type and structure, interfacial chemistry of the soil-water system, and the current density in the soil pore water. Contaminants arriving at the electrodes may potentially be removed from the soil by one of several methods, such as electroplating or adsorption onto the electrode, precipitation or co-precipitation at the electrode, pumping of water near the electrode, or complexing with ion-exchange resins. Experimental results are described on the removal of sodium dichromate and food dye from soil.

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

1992-10-01

59

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

60

Nonlinear electrokinetics at large voltages  

E-print Network

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

Bazant, Martin Z.

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

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

PubMed

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

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

2014-07-01

63

Electrokinetic confinement of axonal growth for dynamically configurable neural networks  

PubMed Central

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

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

2013-01-01

64

Electrokinetic ion transport through unsaturated soil:. 2. Application to a heterogeneous field site  

NASA Astrophysics Data System (ADS)

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 content ranged from 4% to 28% (m 3 m -3). Specially designed ceramic-cased electrodes maintained a steady-state moisture content and electric potential field between the electrodes during the field demonstration. Acetate, a byproduct of acetic acid neutralization of the cathode electrolysis reaction, was transported from the cathode to the anode by electromigration. Field demonstration results indicated preferential transport of acetate through soil layers exhibiting higher moisture content/electrical conductivity. These field transport results agree with theoretical predictions that electromigration velocity is proportional to a power function of the effective moisture content. A numerical model using a homogeneous moisture content/electrical conductivity domain did not adequately predict the acetate field results. Numerical model predictions using a three-layer electrical conductivity/moisture content profile agreed qualitatively with the observed acetate distribution. These results suggest that field heterogeneities must be incorporated into electrokinetic models to predict ion transport at the field-scale.

Mattson, Earl D.; Bowman, Robert S.; Lindgren, Eric R.

2002-01-01

65

Electrokinetic ion transport through unsaturated soil: 2. Application to a heterogeneous field site.  

PubMed

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 content ranged from 4% to 28% (m3 m(-3)). Specially designed ceramic-cased electrodes maintained a steady-state moisture content and electric potential field between the electrodes during the field demonstration. Acetate, a byproduct of acetic acid neutralization of the cathode electrolysis reaction, was transported from the cathode to the anode by electromigration. Field demonstration results indicated preferential transport of acetate through soil layers exhibiting higher moisture content/electrical conductivity. These field transport results agree with theoretical predictions that electromigration velocity is proportional to a power function of the effective moisture content. A numerical model using a homogeneous moisture content/electrical conductivity domain did not adequately predict the acetate field results. Numerical model predictions using a three-layer electrical conductivity/moisture content profile agreed qualitatively with the observed acetate distribution. These results suggest that field heterogeneities must be incorporated into electrokinetic models to predict ion transport at the field-scale. PMID:11848264

Mattson, Earl D; Bowman, Robert S; Lindgren, Eric R

2002-01-01

66

Effect of H(2)SO(4) and HCl in the anode purging solution for the electrokinetic-Fenton remediation of soil contaminated with phenanthrene.  

PubMed

The Electrokinetic-Fenton (EK-Fenton) process is a powerful technology to remediate organic-contaminated soil. The behavior of salts and acids introduced for the pH control has significant influence on the H(2)O(2) stabilization and destruction of organic contaminants. In this study, the effects of the type and concentration of acids, which were introduced at the anode, were investigated for the treatment of clayey soil contaminated with phenanthrene. In experiments with H(2)SO(4) as the anode solution, H(2)O(2) concentration in the anode reservoir decreased due to reaction between reduced species of sulfate and H(2)O(2), as time elapsed. By contrast, HCl as an electrolyte in the anode reservoir did not decrease the H(2)O(2) concentration in the anode reservoir. The reaction between the reduced species of sulfate and H(2)O(2) hindered the stabilization of H(2)O(2) in the soil and anode reservoir. In experiments with HCl for pH control, Cl(.), and Cl(2)(. -), which could be generated with mineral catalyzed Fenton-like reaction, did not significantly hinder H(2)O(2) stabilization. H(2)O(2) transportation with electro-osmotic flow and mineral catalyzed Fenton-like reaction on the soil surface resulted in the simultaneous transport and degradation of phenanthrene, which are dependent of the advancement rate of the acid front and electro-osmotic flow toward the cathode according to HCl and H(2)SO(4) concentrations in the anode purging solution. PMID:19847701

Kim, Jung-Hwan; Kim, Jong Yun; Kim, Soo-Sam

2009-09-01

67

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

68

An AC electrokinetics facilitated biosensor cassette for rapid pathogen identification.  

PubMed

To develop a portable point-of-care system based on biosensors for common infectious diseases such as urinary tract infection, the sensing process needs to be implemented within an enclosed fluidic system. On chip sample preparation of clinical samples remains a significant obstacle to achieving robust sensor performance. Herein AC electrokinetics is applied in an electrochemical biosensor cassette to enhance molecular convection and hybridization efficiency through electrokinetics induced fluid motion and Joule heating induced temperature elevation. Using E. coli as an exemplary pathogen, we determined the optimal electrokinetic parameters for detecting bacterial 16S rRNA in the biosensor cassette based on the current output, signal-to-noise ratio, and limit of detection. In addition, a panel of six probe sets targeting common uropathogenic bacteria was demonstrated. The optimized parameters were also validated using patient-derived clinical urine samples. The effectiveness of electrokinetics for on chip sample preparation will facilitate the implementation of point-of-care diagnosis of urinary tract infection in the future. PMID:23626988

Ouyang, Mengxing; Mohan, Ruchika; Lu, Yi; Liu, Tingting; Mach, Kathleen E; Sin, Mandy L Y; McComb, Mason; Joshi, Janhvi; Gau, Vincent; Wong, Pak Kin; Liao, Joseph C

2013-07-01

69

AC Electrokinetics Facilitated Biosensor Cassette for Rapid Pathogen Identification  

PubMed Central

To develop a portable point-of-care system based on biosensors for common infectious diseases such as urinary tract infection, the sensing process needs to be implemented within an enclosed fluidic system. On chip sample preparation of clinical samples remains a significant obstacle to achieve robust sensor performance. Herein AC electrokinetics is applied in an electrochemical biosensor cassette to enhance molecular convection and hybridization efficiency though electrokinetic induced fluid motion and Joule heating induced temperature elevation. Using E. coli as an exemplary pathogen, we determined the optimal electrokinetic parameters for detecting bacterial 16S rRNA in the biosensor cassette based on the current output, signal-to-noise ratio, and limit of detection. In addition, a panel of six probe sets targeting common uropathogenic bacteria was demonstrated. The optimized parameters were also validated using patient-derived clinical urine samples. The effectiveness of electrokinetic for on chip sample preparation will facilitate the implementation of point-of-care diagnosis of urinary tract infection in the future. PMID:23626988

Ouyang, Mengxing; Mohan, Ruchika; Lu, Yi; Liu, Tingting; Mach, Kathleen E.; Sin, Mandy L. Y.; McComb, Mason; Joshi, Janhvi; Gau, Vincent

2013-01-01

70

Electrokinetics of pure clay minerals revisited  

SciTech Connect

Clay minerals have long attracted the attention of colloid scientists. This paper considers, specifically, their important role in the transport of various contaminants from land to sea, e.g., metal ions and organic detrital and man-made material in watercourses. Advance in experimental techniques have enabled precise characterization of clays and then electrokinetic experiments at high electrolyte concentrations, such as in seawater. Three of the most important clay minerals encountered in suspended matter in natural waters, montmorillonite, illite, and chlorite, were prepared in a very pure state. Electrokinetic experiments were done in pure aqueous single and complex electrolyte solutions and in solutions in which natural organic matter was simulated using a humic substance, fulvic acid, of defined provenance and properties, typical of riverine waters. An isoelectric point was found at pH 5.0 {+-} 0.2 for chlorite; none were found for illite and montmorillonite. Only Ca{sup 2+} showed a charging effect on chlorite, indeed a reversal of sign from negative to positive at 1 {times} 10{sup {minus}3} mol dm{sup {minus}3}. Addition of fulvic acid affected only chlorite, illite less, and Na montmorillonite not at all.

Sondi, I.; Biscan, J.; Pravdic, V. [Rudjer Boskovic Inst., Zagreb (Croatia). Center for Marine Research] [Rudjer Boskovic Inst., Zagreb (Croatia). Center for Marine Research

1996-03-25

71

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

72

Effect of pendant chain lengths and backbone functionalities on the chemical selectivity of sulfonated amphiphilic copolymers as pseudo-stationary phases in electrokinetic chromatography  

Microsoft Academic Search

Amphiphilic copolymers of AMPS (2-acrylamido-2-methyl-1-propanesulfonic acid) and hydrophobic monomers with various chemical structures were synthesized, characterized and used as novel electrokinetic chromatography polymeric pseudo-stationary phases, showing significant chemical selectivity differences from that of the conventional monomeric pseudo-stationary phase, sodium lauryl sulphate. Copolymers of AMPS and methacrylates with different pendant chain lengths (C8, C12 and C18) were investigated and no significant

Wei Shi; Dominic S Peterson; Christopher P Palmer

2001-01-01

73

REMOVAL OF RADIONUCLIDES BY ELECTROKINETIC SOIL PROCESSING  

EPA Science Inventory

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

74

Electrokinetic remediation of copper mine tailings  

Microsoft Academic Search

Important process parameters to optimize in electrokinetic soil remediation are those influencing remediation time and power consumption since these directly affect the cost of a remediation action. This work shows how the electrokinetic remediation (EKR) process could be improved by implementing bipolar electrodes in the porous material. The bipolar electrodes in EKR meant two improvements: (1) a shorter migration pathway

Henrik K. Hansen; Adrian Rojo; Lisbeth M. Ottosen

2007-01-01

75

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

76

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

77

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

78

The effects of incorporating dynamic data on estimates of uncertainty  

E-print Network

that incorporating dynamic data in a reservoir model will result in lower estimates of uncertainty than considering only static data. However, incorporation of dynamic data does not guarantee that the forecasted ranges will encompass the true value. Reliability...

Mulla, Shahebaz Hisamuddin

2004-09-30

79

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

80

Cosolvent-enhanced electrokinetic remediation of soils contaminated with phenanthrene  

SciTech Connect

This research was carried out to evaluate feasibility of using an electrokinetic technique to remove hydrophobic organic pollutants from soils, with the assistance of a cosolvent (n-butylamine, tetrahydrofuran, or acetone) added to the conducting fluid. The experiments were carried out on glacial till clay with phenanthrene as the test compound. Desorption equilibrium was investigated by batch tests. The electrokinetic experiments were conducted using a 19.1 cm long x 6.2 cm inside diameter column under controlled voltage. Water or 20% (volume) cosolvent solution was constantly supplied at the anode. The concentration of phenanthrene in the effluent collected at the cathode was monitored. Each experiment lasted for 100 to 145 days. Results showed that the presence of n-butylamine significantly enhanced the desorption and electrokinetic transport of phenanthrene; about 43% of the phenanthrene was removed after 127 days or 9 pore volumes. The effect of acetone was not as significant as butylamine. The effluent flow in the tetrahydrofuran experiments was minimal, and phenanthrene was not detected in the effluent. The use of water as the conducting solution did not cause observable phenanthrene migration.

Li, A.; Cheung, K.A.; Reddy, K.R.

2000-06-01

81

Nonlinear free vibration of piezoelectric nanobeams incorporating surface effects  

NASA Astrophysics Data System (ADS)

In this study, the nonlinear free vibration of piezoelectric nanobeams incorporating surface effects (surface elasticity, surface tension, and surface density) is studied. The governing equation of the piezoelectric nanobeam is derived within the framework of Euler-Bernoulli beam theory with the von Kármán geometric nonlinearity. In order to satisfy the balance conditions between the nanobeam bulk and its surfaces, the component of the bulk stress, ?zz, is assumed to vary linearly through the nanobeam thickness. An exact solution is obtained for the natural frequencies of a simply supported piezoelectric nanobeam in terms of the Jacobi elliptic functions using the free vibration mode shape of the corresponding linear problem. Then, the influences of the surface effects and the piezoelectric field on the nonlinear free vibration of nanobeams made of aluminum and silicon with positive and negative surface elasticity, respectively, have been studied for various properties of the piezoelectric field, various nanobeam sizes and amplitude ratios. It is observed that if the Young’s modulus of a nanobeam is lower, the effect of the piezoelectric field on the frequency ratios (FRs) of the nanobeam will be greater. In addition, it is seen that by increasing the nanobeam length so that the nanobeam cross section is set to be constant, the surface effects and the piezoelectric field with negative voltage values increases the FRs, whereas it is the other way around when the nanobeam cross section is assumed to be dependent on the length of the nanobeam.

Hosseini-Hashemi, Shahrokh; Nahas, Iman; Fakher, Mahmood; Nazemnezhad, Reza

2014-03-01

82

Multiconfigurational nuclear-electronic orbital approach: Incorporation of nuclear quantum effects in electronic structure calculations  

E-print Network

Multiconfigurational nuclear-electronic orbital approach: Incorporation of nuclear quantum effects are that nuclear quantum effects are incorporated during the electronic structure calculation, the Born basis functions. They also enable the location and characterization of geometry stationary points

Hammes-Schiffer, Sharon

83

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

84

Electrokinetic Concentration of DNA Polymers in Nanofluidic Channels  

E-print Network

Electrokinetic Concentration of DNA Polymers in Nanofluidic Channels Derek Stein,, Zeno Deurvorst on this understanding by demonstrating how a nanofluidic device with integrated electrodes can preconcentrate DNA. KEYWORDS Nanofluidic, DNA, electrokinetic, concentration M iniature fluidic devices are having an important

Dekker, Cees

85

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

86

Convective instability of electrokinetic flows in a cross-shaped microchannel  

NASA Astrophysics Data System (ADS)

We present a parametric experimental study of convective electrokinetic instability (EKI) in an isotropically etched, cross-shaped microchannel using quantitative epifluorescence imaging. The base state is a three-inlet, one-outlet electrokinetic focusing flow configuration where the centre sample stream and sheath flows have mismatched ionic conductivities. Electrokinetic flows with conductivity gradients become unstable when the electroviscous stretching and folding of conductivity interfaces grows faster than the dissipative effect of molecular diffusion. Scalar images, critical applied fields required for instability, and temporal and spatial scalar energy are presented for flows with a wide range of applied d.c. electric field and centre-to-sheath conductivity ratios. These parameters impose variations of the electric Rayleigh number across four orders of magnitude. We introduce a scaling for charge density in the bulk fluid as a function of local maximum conductivity gradients in the flow. This scaling shows that the flow becomes unstable at a critical electric Rayleigh number (Ra_{e, ?} {=} 205) and applies to a wide range of applied field and centre-to-sheath conductivity ratios. This work is relevant to on-chip electrokinetic flows with conductivity gradients such as field amplified sample stacking, flow at the intersections of multi-dimensional assays, electrokinetic control and separation of sample streams with poorly specified chemistry, and low-Reynolds number micromixing.

Posner, Jonathan D.; Santiago, Juan G.

2006-05-01

87

Enhanced electrokinetic remediation of lead-contaminated soil by complexing agents and approaching anodes.  

PubMed

Optimizing process parameters that affect the remediation time and power consumption can improve the treatment efficiency of the electrokinetic remediation as well as determine the cost of a remediation action. Lab-scale electrokinetic remediation of Pb-contaminated soils was investigated for the effect of complexant ethylenediaminetetraacetic acid (EDTA) and acetic acid and approaching anode on the removal efficiency of Pb. When EDTA was added to the catholyte, EDTA dissolved insoluble Pb in soils to form soluble Pb-EDTA complexes, increasing Pb mobility and accordingly removal efficiency. The removal efficiency was enhanced from 47.8 to 61.5 % when the EDTA concentration was increased from 0.1 to 0.2 M, showing that EDTA played an important role in remediation. And the migration rate of Pb was increased to 72.3 % when both EDTA and acetic acid were used in the catholyte. The "approaching anode electrokinetic remediation" process in the presence of both EDTA and acetic acid had a higher Pb-removal efficiency with an average efficiency of 83.8 %. The efficiency of electrokinetic remediation was closely related to Pb speciation. Exchangeable and carbonate-bounded Pb were likely the forms which could be removed. All results indicate that the approaching anode method in the presence of EDTA and acetic acid is an advisable choice for electrokinetic remediation of Pb-contaminated soil. PMID:24203258

Zhang, Tao; Zou, Hua; Ji, Minhui; Li, Xiaolin; Li, Liqiao; Tang, Tang

2014-02-01

88

Incorporation of Source Material: The Effect of Instruction  

ERIC Educational Resources Information Center

An important aspect of advanced academic writing is the ability to incorporate source material. Yet this ability often poses considerable challenges for international ESL students. Although a number of scholars have called for the explicit teaching of how to acknowledge and incorporate source materials, research evidence on whether explicit…

Storch, Neomy

2012-01-01

89

ANTIMICROBIAL EFFECTS ON STARCH-BASED FILMS INCORPORATED WITH LYSOZYMES  

Microsoft Academic Search

An antimicrobial (AM) Active Packaging can be made by incorporating and immobilizing suitable AM agents into food packages and applying a bio switch concept. A starch-based film was prepared and incorporated with antimicrobial agents, i.e. lysozyme and EDTA as chelating agent. This film was then inoculated with the bacteria Escherichia coli and Bacillus subtilis to carry out the microbial contamination

Nozieana Khairuddin; Ida Idayu Muhamad

90

Electrokinetics of Polar Liquids in Contact with Non-Polar Surfaces  

E-print Network

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

Lin, Chih-Hsiu; Chaudhury, Manoj K

2014-01-01

91

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

92

Bound soda incorporation during hydrate precipitation -- Effects of caustic, temperature and organics  

SciTech Connect

Soda is incorporated into aluminum tri-hydroxide (hydrate) during the precipitation stage of the Bayer Process. A review of literature shows the predominant effect is alumina supersaturation. This research extends the literature by quantifying the secondary effects of temperature, caustic and organics on soda incorporation beyond the primary effect through alumina supersaturation. This work advances industry knowledge towards better control of soda incorporation in the refinery in the pursuit of higher and more consistent product quality for smelter grade alumina.

Armstrong, L.; Hunter, J.; McCormick, K.; Warren, H. [Queensland Alumina Ltd., Gladstone, Queensland (Australia)

1996-10-01

93

Determination of hesperetin, cinnamic acid and nicotinic acid in propolis with micellar electrokinetic capillary chromatography  

Microsoft Academic Search

Micellar electrokinetic capillary chromatography (MEKC) has been used to determine hesperetin, cinnamic acid and nicotinic acid in propolis. After systematically study the effect of buffer concentration and pH, micellar concentration, organic modifier, applied voltage and injection time, the analytical conditions were optimized. Under the optimized conditions, the three analytes could be well separated in 20 min. A good linearity between

Y Lu; C Wu; Z Yuan

2004-01-01

94

Nonlinear electrokinetic flow about a polarized conducting drop  

NASA Astrophysics Data System (ADS)

In the thin-double-layer limit ?a?1, electrokinetic flows about free surfaces are driven by a combination of an electro-osmotic slip and effective shear-stress jump. An intriguing case is that of a highly conducting liquid drop of radius a, where the inability to balance the viscous shear by Maxwell stresses results in an O(?a) velocity amplification relative to the familiar electro-osmotic scale. To illuminate the inherent nonlinearity we consider uncharged drops, where the induced surface-charge distribution results in a fore-aft symmetric electrokinetic flow profile with no attendant drop translation. This problem is analyzed using a macroscale model, where the double layer is represented by effective boundary conditions. Because of the intense flow, ionic convection within the O(1/?)-wide diffuse-charge layer is manifested by a moderate-zeta-potential surface-conduction effect. The drop deforms to a prolate shape in response to the combination of hydrodynamic forces and the effective electrocapillary reduction of the surface-tension coefficient, both mechanisms being asymptotically comparable. The flow field and the concomitant drop deformation are calculated using both a weak-field approximation and numerical simulations of the nonlinear macroscale model.

Schnitzer, Ory; Yariv, Ehud

2013-04-01

95

Opto-electrokinetic manipulation technique for highperformance  

SciTech Connect

This communication first demonstrates bio-compatibility of a recently developed opto-electrokinetic manipulation technique, using microorganisms. Aggregation, patterning, translation, trapping and size-based separation of microorganisms performed with the technique firmly establishes its usefulness for development of a high-performance on-chip bioassay system.

Kwon, Jae-Sung [Purdue University; Ravindranath, Sandeep [Purdue University; Kumar, Aloke [ORNL; Irudayaraj, Joseph [Purdue University; Wereley, Steven T. [Purdue University

2012-01-01

96

Nonlinear electrokinetic phenomena in microfluidic devices  

NASA Astrophysics Data System (ADS)

This thesis addresses nonlinear electrokinetic mechanisms for transporting fluid and particles in microfluidic devices for potential applications in biomedical chips, microelectronic cooling and micro-fuel cells. Nonlinear electrokinetics have many advantages, such as low voltage, low power, high velocity, and no significant gas formation in the electrolyte. However, they involve new and complex charging and flow mechanisms that are still not fully understood or explored. Linear electrokinetic fingering that occurs when a fluid with a lower electrolyte concentration advances into one with a higher concentration is first analyzed. Unlike earlier miscible fingering theories, the linear stability analysis is carried out in the self-similar coordinates of the diffusing front. This new spectral theory is developed for small-amplitude gravity and viscous miscible fingering phenomena in general and applied to electrokinetic miscible fingering specifically. Transient electrokinetic fingering is shown to be insignificant in sub-millimeter micro-devices. Nonlinear electroosmotic flow around an ion-exchange spherical granule is studied next. When an electric field is applied across a conducting and ion-selective porous granule in an electrolyte solution, a polarized surface layer with excess counter-ions is created. The flux-induced polarization produces a nonlinear slip velocity to produce micro-vortices around this sphere. This polarization layer is reduced by convection at high velocity. Two velocity scalings at low and high electric fields are derived and favorably compared with experimental results. A mixing device based on this mechanism is shown to produce mixing efficiency 10-100 times higher than molecular diffusion. Finally, AC nonlinear electrokinetic flow on planar electrodes is studied. Two double layer charging mechanisms are responsible for the flow---one due to capacitive charging of ions from the bulk electrolyte and one due to Faradaic reactions at the electrode that consume or produce ions in the double layer. Faradaic charging is analyzed for specific reactions. From the theory, particular electrokinetic flows above the electrodes are selected for micropumps and bioparticle trapping by specifying the electrode geometry and the applied voltage and frequency.

Ben, Yuxing

97

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

98

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

99

Improving electrokinetic microdevice stability by controlling electrolysis bubbles.  

PubMed

The voltage-operating window for many electrokinetic microdevices is limited by electrolysis gas bubbles that destabilize microfluidic system causing noise and irreproducible responses above ?3 V DC and less than ?1 kHz AC at 3 Vpp. Surfactant additives, SDS and Triton X-100, and an integrated semipermeable SnakeSkin® membrane were employed to control and assess electrolysis bubbles from platinum electrodes in a 180 by 70 ?m, 10 mm long microchannel. Stabilized current responses at 100 V DC were observed with surfactant additives or SnakeSkin® barriers. Electrolysis bubble behaviors, visualized via video microscopy at the electrode surface and in the microchannels, were found to be influenced by surfactant function and SnakeSkin® barriers. Both SDS and Triton X-100 surfactants promoted smaller bubble diameters and faster bubble detachment from electrode surfaces via increasing gas solubility. In contrast, SnakeSkin® membranes enhanced natural convection and blocked bubbles from entering the microchannels and thus reduced current disturbances in the electric field. This data illustrated that electrode surface behaviors had substantially greater impacts on current stability than microbubbles within microchannels. Thus, physically blocking bubbles from microchannels is less effective than electrode functionalization approaches to stabilize electrokinetic microfluidic systems. PMID:24648277

Lee, Hwi Yong; Barber, Cedrick; Minerick, Adrienne R

2014-07-01

100

Computing the Electrokinetic Response with Simple Models via Eigenvalue Decomposition  

NASA Astrophysics Data System (ADS)

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

Kuhlman, K. L.; Malama, B.

2010-12-01

101

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

102

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

103

Immersed molecular electrokinetic finite element method  

NASA Astrophysics Data System (ADS)

A unique simulation technique has been developed capable of modeling electric field induced detection of biomolecules such as viruses, at room temperatures where thermal fluctuations must be considered. The proposed immersed molecular electrokinetic finite element method couples electrokinetics with fluctuating hydrodynamics to study the motion and deformation of flexible objects immersed in a suspending medium under an applied electric field. The force induced on an arbitrary object due to an electric field is calculated based on the continuum electromechanics and the Maxwell stress tensor. The thermal fluctuations are included in the Navier-Stokes fluid equations via the stochastic stress tensor. Dielectrophoretic and fluctuating forces acting on the particle are coupled through the fluid-structure interaction force calculated within the surrounding environment. This method was used to perform concentration and retention efficacy analysis of nanoscale biosensors using gold particles of various sizes. The analysis was also applied to a human papillomavirus.

Kopacz, Adrian M.; Liu, Wing K.

2013-07-01

104

Incorporating Teacher Effectiveness into Teacher Preparation Program Evaluation  

ERIC Educational Resources Information Center

New federal and state policies require that teacher preparation programs (TPP) be held accountable for the effectiveness of their graduates as measured by test score gains of the students they teach. In this article, the authors review the approaches taken in several states that have already estimated TPP effects and analyze the proposals for…

Henry, Gary T.; Kershaw, David C.; Zulli, Rebecca A.; Smith, Adrienne A.

2012-01-01

105

Incorporating conservation zone effectiveness for protecting biodiversity in marine planning.  

PubMed

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

106

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

107

Electrokinetic molecular separation in nanoscale fluidic channels  

Microsoft Academic Search

This report presents a study of electrokinetic transport in a series of integrated macro- to nano- fluidic chips that allow for controlled injection of molecular mixtures into high-density arrays of nanochannels. The high-aspect-ratio nanochannels were fabricated on a Si wafer using interferometric lithography and standard semiconductor industry processes, and are capped with a transparent Pyrex cover slip to allow for

Anthony L. Garcia; Linnea K. Ista; Dimiter N. Petsev; Michael J. O'Brien; Paul Bisong; Andrea A. Mammoli; Steven R. J. Brueckc; Gabriel P. Lopez

2005-01-01

108

GENERALIZED PARTIALLY LINEAR MIXED-EFFECTS MODELS INCORPORATING MISMEASURED COVARIATES  

PubMed Central

In this article we consider a semiparametric generalized mixed-effects model, and propose combining local linear regression, and penalized quasilikelihood and local quasilikelihood techniques to estimate both population and individual parameters and nonparametric curves. The proposed estimators take into account the local correlation structure of the longitudinal data. We establish normality for the estimators of the parameter and asymptotic expansion for the estimators of the nonparametric part. For practical implementation, we propose an appropriate algorithm. We also consider the measurement error problem in covariates in our model, and suggest a strategy for adjusting the effects of measurement errors. We apply the proposed models and methods to study the relation between virologic and immunologic responses in AIDS clinical trials, in which virologic response is classified into binary variables. A dataset from an AIDS clinical study is analyzed. PMID:20160899

Liang, Hua

2009-01-01

109

Effective Design of E-learning Application Incorporating Multiple Intelligences  

Microsoft Academic Search

\\u000a Electronic learning (e-learning) is currently a common concept, and this is due to an attempt by many educational sectors\\u000a to develop structures and systems that are more adaptable and responsive to changes. The real effectiveness of e-learning\\u000a applications lies in the recognition by the educator and the learner that all people have learning strengths and weaknesses.\\u000a Within the field of

Kemalatha Krishnasamy; Sai Peck Lee; Sellappan Palaniappan

2003-01-01

110

Development of Guidelines for Incorporation of Vertical Ground Motion Effects in Seismic Design of Highway Bridges.  

National Technical Information Service (NTIS)

This study was undertaken with the objective of assessing the current provisions in SDC-2006 for incorporating vertical effects of ground motions in seismic evaluation and design of ordinary highway bridges. A comprehensive series of simulations was carri...

E. Erduran, N. Abrahamson, S. K. Kunnath, Y. H. Chai, Z. Yilmaz

2008-01-01

111

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

Microsoft Academic Search

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

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

2010-01-01

112

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

113

Incorporating plant functional diversity effects in ecosystem service assessments  

PubMed Central

Global environmental change affects the sustained provision of a wide set of ecosystem services. Although the delivery of ecosystem services is strongly affected by abiotic drivers and direct land use effects, it is also modulated by the functional diversity of biological communities (the value, range, and relative abundance of functional traits in a given ecosystem). The focus of this article is on integrating the different possible mechanisms by which functional diversity affects ecosystem properties that are directly relevant to ecosystem services. We propose a systematic way for progressing in understanding how land cover change affects these ecosystem properties through functional diversity modifications. Models on links between ecosystem properties and the local mean, range, and distribution of plant trait values are numerous, but they have been scattered in the literature, with varying degrees of empirical support and varying functional diversity components analyzed. Here we articulate these different components in a single conceptual and methodological framework that allows testing them in combination. We illustrate our approach with examples from the literature and apply the proposed framework to a grassland system in the central French Alps in which functional diversity, by responding to land use change, alters the provision of ecosystem services important to local stakeholders. We claim that our framework contributes to opening a new area of research at the interface of land change science and fundamental ecology. PMID:18093933

Diaz, Sandra; Lavorel, Sandra; de Bello, Francesco; Quetier, Fabien; Grigulis, Karl; Robson, T. Matthew

2007-01-01

114

Enhancement of In Vivo Anticancer Effect of Cisplatin by Incorporation Inside Carbon Nanohorns  

NASA Astrophysics Data System (ADS)

We have been studying potential applications of single-wall carbon nanohorns (SWNHs) to drug delivery systems. SWNHs are multiply functionalized with proteins, magnetites, tumor targeting molecules, and others. Various drugs are easily incorporated, and the incorporated drugs are slowly released. Almost no acute toxicity of SWNHs was found through various animal tests. We show in this report that anticancer effect of cisplatin was enhanced by incorporation inside SWNHs (CDDP@SWNH) as evidenced by in vivo tests: CDDP@SWNH was locally injected to tumors subcutaneously transplanted on mice. CDDP@SWNH inhibited the tumor growth more effectively than CDDP. This anticancer enhancement was achieved by large CDDP-quantity incorporated inside SWNH, slow release of CDDP from SWNH, long-term stay of SWNHs at the tumor sites, and an anticancer effect of SWNH itself [1].[3pt] [1] K. Ajima et al. ACSNano, 10(2008)2057-2064.

Yudasaka, Masako; Ajima, Kumiko; Murakami, Tatsuya; Mizoguchi, Yoshikazu; Tsuchida, Kunihiro; Ichihashi, Toshinari; Iijima, Sumio

2009-03-01

115

ELECTROKINETIC DENSIFICATION OF COAL FINES IN WASTE PONDS  

SciTech Connect

The objective of this research is 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. In this experimental and analytical study the authors elucidate the transport processes that control the rate of concentrated colloidal particle removal, demonstrate the process on a laboratory scale, and develop the scale-up laws needed to design commercial-scale processes. The authors are also addressing the fundamental problems associated with particle-particle interactions (electrical and hydrodynamic), the effects of particle concentration on the applied electric field, the electrochemical reactions that occur at the electrodes, and the prediction of power requirements.

E. James Davis

1998-05-01

116

ELECTROKINETIC DENSIFICATION OF COAL FINES IN WASTE PONDS  

SciTech Connect

The objective of this research is 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. In this experimental and analytical study the authors elucidate the transport processes that control the rate of concentrated colloidal particle removal, demonstrate the process on a laboratory scale, and develop the scale-up laws needed to design commercial-scale processes. They then address the fundamental problems associated with particle-particle interactions (electrical and hydrodynamic), the effects of particle concentration on the applied electric field, the electrochemical reactions that occur at the electrodes, and the prediction of power requirements.

E. James Davis

1997-04-30

117

Temperature dependence of electrokinetic flux in Si nanochannel  

E-print Network

Significant temperature effects on the electrokinetic transport in a nanochannel with a slab geometry are demonstrated using a molecular dynamics (MD) model. A system consisting of Na+ and Cl- ions dissolved in water and confined between fixed crystalline silicon walls with negatively charged inner surfaces in an external electric field was investigated. Lennard-Jones (LJ) force fields and Coulomb electrostatic interactions with Simple Point Charge Extended (SPC/E) model were used to represent the interactions between ions, water molecules, and channel wall atoms. Dependence of the flow of water and ions on the temperature was examined. The magnitude of the water flux and even its direction are shown to be significantly affected by temperature. In particular, the previously reported flow reversal phenomenon does not occur at higher temperature. Temperature dependence of the flux was attributed to the charge redistribution and to the changes in viscosity of water.

B. Jelinek; S. D. Felicelli; P. F. Mlakar; J. F. Peters

2009-10-30

118

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

119

Multiphase electrodes for microbead control applications: integration of DEP and electrokinetics for bio-particle positioning.  

PubMed

Advances in microfabrication have introduced new possibilities for automated, high-throughput biomedical investigations and analysis. Physical effects such as dielectrophoresis (DEP) and AC electrokinetics can be used to manipulate particles in solution to coordinate a sequence of bioanalytical processing steps. DEP is accomplished with non-uniform electric fields that can polarize particles (microbeads, cells, viruses, DNA, proteins, etc.) in suspension causing translational or rotational movement. AC electrokinetics is another phenomena involved with movement of particles in suspension with electric fields and is comprised of both electro-thermal and electro-osmotic effects. This paper investigates single layer electrodes that are effective for particle localization and clustering based on DEP and AC electrokinetic effects. We demonstrate a novel multi-electrode setup capable of clustering particles into an array of discrete bands using activated and electrically floating electrodes. These bands shift to adjacent regions on the electrode surface by altering the electrode activation scheme. The predictability of particle placement to specific locations provides new opportunities for integration and coordination with raster scanning lasers or a charge coupled device (CCD) for advanced biomedical diagnostic devices, and more sophisticated optical interrogation techniques. PMID:17112718

Yantzi, J D; Yeow, J T W; Abdallah, S S

2007-05-15

120

Simultaneous determination of fat- and water-soluble vitamins by microemulsion electrokinetic chromatography  

Microsoft Academic Search

A new procedure was developed for the simultaneous determination of water- and fat-soluble vitamins by microemulsion electrokinetic\\u000a chromatography. Using microemulsions based on sodium dodecyl sulfate, Brij 35, 1-butanol, and heptane, 10 vitamins were separated\\u000a (4 water-soluble and 6 fat-soluble) within 35 min. The efficiency of the separation was 800000 theoretical plates (effective\\u000a capillary length, 40 cm). To enhance the selectivity,

E. P. Svidritskii; E. B. Pashkova; A. V. Pirogov; O. A. Shpigun

2010-01-01

121

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

122

Stability-indicating micellar electrokinetic chromatography method for the analysis of sumatriptan succinate in pharmaceutical formulations  

Microsoft Academic Search

A micellar electrokinetic chromatography method for the determination of sumatriptan succinate in pharmaceutical formulations was developed. The effects of several factors such as pH, surfactant and buffer concentration, applied voltage, capillary temperature, and injection time were investigated. Separation took about 5min using phenobarbital as internal standard. The separation was carried out in reversed polarity mode at 20°C, 26kV and using

Khaldun M. Al Azzam; Bahruddin Saad; Chai Yuan Tat; Ishak Mat; Hassan Y. Aboul-Enein

2011-01-01

123

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.

124

Electrokinetic Transport and Manipulation of Particles in Microfluidic Reservoirs  

NASA Astrophysics Data System (ADS)

Electrically controlled microfluidic devices have been proven to be very useful in manipulating both synthetic and biological particles in terms of efficiency, sensitivity, and simplicity. The success of these devices depends on a comprehensive understanding of electrokinetic particle transport in every part of their microchannels and reservoirs. In this talk we present an experimental and numerical study of the electrokinetic transport of spherical polystyrene beads in microfluidic reservoirs. We also demonstrate that polystyrene beads can be continuously focused, trapped, concentrated, and separated in microfluidic reservoirs. This diverse electrical control of particle transport in reservoirs is envisioned to open new possibilities for handling bioparticles in electrokinetic microfluidic systems.

Zhu, Junjie; Xuan, Xiangchun

2010-11-01

125

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

126

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

PubMed Central

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

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

2014-01-01

127

Sharing a World of Resources: Incorporating Science Content in Effective Interpretation  

Microsoft Academic Search

Incorporating science content into the presentation of resource issues to the public is essential for effective interpretation. Science professionals are eager to share their work; interpreters are equally eager to learn about relevant science. Yet, interpreting science and resource issues remains a challenge. Professional development for interpreters is critical to effectively address this challenge. Here, we describe a proven model

Anita Davis; Ruth Paglierani

128

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

E-print Network

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

Nowack, Robert L.

129

Designing an Optimal DC Electrokinetic Pump  

NASA Astrophysics Data System (ADS)

A sol-gel process is used to fabricate a medium for DC electrokinetic pumps such that its micron-sized through pore is comparable in dimension to the surface double layer thickness of weak electrolytes and organic solvents. Under such conditions, the opposite double layers within the channel do not overlap to reduce the total polarization, as in nanoporous materials, and yet the hydrodynamic shear stress spans the entire channel to relieve the large viscous dissipation associated with electrokinetic flows. The silica matrix is wettable by most solvents and possesses a large surface charge density both necessary features for a good DC pump medium. As there is almost no electro-neutral fluid within the medium, we observed a curios phenomenon associated with this matrix--the DC current through it is due almost entirely to advection current. AS such, the pump can function as a flow sensor and a constant flow rate can be maintained against a varying load by controlling the current. The maximum flow rate and maximum pressure generated by the pump housed in a 100-micron capillary are 2 microL/min and 0.4 MPa , respectively, at 6 kV. We have measured the pressure curves of this pump for a variety of solvents and ion concentrations to verify the optimality of the pump and the dominance of advection current.

Wang, Ping; Chen, Zilin; Chang, Hsueh-Chia

2004-11-01

130

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...

131

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 ...

132

Robust and high-resolution simulations of nonlinear electrokinetic processes in variable cross-section channels.  

PubMed

We present a model and an associated numerical scheme to simulate complex electrokinetic processes in channels with nonuniform cross-sectional area. We develop a quasi-1D model based on local cross-sectional area averaging of the equations describing unsteady, multispecies, electromigration-diffusion transport. Our approach uses techniques of lubrication theory to approximate electrokinetic flows in channels with arbitrary variations in cross-section; and we include chemical equilibrium calculations for weak electrolytes, Taylor-Aris type dispersion due of nonuniform bulk flow, and the effects of ionic strength on species mobility and on acid-base equilibrium constants. To solve the quasi-1D governing equations, we provide a dissipative finite volume scheme that adds numerical dissipation at selective locations to ensure both unconditional stability and high accuracy. We couple the numerical scheme with a novel adaptive grid refinement algorithm that further improves the accuracy of simulations by minimizing numerical dissipation. We benchmark our numerical scheme with existing numerical schemes by simulating nonlinear electrokinetic problems, including ITP and electromigration dispersion in CZE. Simulation results show that our approach yields fast, stable, and high-resolution solutions using an order of magnitude less grid points compared to the existing dissipative schemes. To highlight our model's capabilities, we demonstrate simulations that predict increase in detection sensitivity of ITP in converging cross-sectional area channels. We also show that our simulations of ITP in variable cross-sectional area channels have very good quantitative agreement with published experimental data. PMID:22996734

Bahga, Supreet S; Bercovici, Moran; Santiago, Juan G

2012-10-01

133

Dual-asymmetry electrokinetic flow focusing for pre-concentration and analysis of catecholamines in CE electrochemical nanochannels.  

PubMed

In this research, a technique incorporating dual-asymmetry electrokinetic flow (DAEKF) was applied to a nanoCE electrochemical device for the pre-concentration and detection of catecholamines. The DAEKF was constructed by first generating a zeta-potential difference between the top and bottom walls, which had been pre-treated with O2 and H2O surface plasma, respectively, yielding a 2-D gradient shear flow across the channel depth. The shear flow was then exposed to a varying zeta-potential along the downstream direction by control of the field-effect in order to cause downward rotational flow in the channel. By this mechanism, almost all of the samples were effectively brought down to the electrode surface for analysis. Simulations were carried out to reveal the mechanism of concentration caused by the DAEKF, and the results reasonably describe our experiment findings. This DAEKF technique was applied to a glass/glass CE electrochemical nanochip for the analysis of catecholamines. The optimum detection limit was determined to be 1.25 and 3.3 nM of dopamine and catechol, respectively. A detection limit at the zeptomole level for dopamine can be obtained in this device, which is close to the level released by a single neuron cell in vitro. PMID:19639573

Wu, Ren-Guei; Yang, Chung-Shi; Lian, Cheng-Kuang; Cheing, Ching-Chang; Tseng, Fan-Gang

2009-07-01

134

Electrokinetic sample injection for high-sensitivity CZE (part 2): improving the quantitative repeatability and application of electrokinetic supercharging-CZE to the detection of atmospheric electrolytes.  

PubMed

Electrokinetic supercharging (EKS) is defined as a technique that combines electrokinetic sample injection with transient ITP. Quantitative repeatability of EKS-CZE and the other CE methods using electrokinetic sample injection process is usually inferior in comparison with the CE methods using hydrodynamic or hydrostatic injection. This is due to some effects, such as the temperature change and the convection of the sample solution in the reservoir, as well as the change of the distance between an electrode and a capillary end (D(ec)). In particular, we have found that the D(ec) change might most seriously affect the repeatability, especially when the electrode is a thin Pt wire that could be unintentionally bent during sampling. By using a Teflon spacer to fix D(ec) to 1.1 mm, the RSD of peak area (n=5) was decreased from 20 to 3.4% in EKS-CZE for several metal cations. This D(ec) dependence of the sample amount injected was supported by computer simulation using CFD-ACE+ software. The improved repeatability (down to 5.1% at n=5, averaged RSD for Co(2+), Li(+), Ni(2+), Zn(2+) and Pb(2+)) was also experimentally attained by increasing the D(ec) to ca. 20 mm, which was also effective to obtain high sensitivity. Since the temperature and the convection effects on the repeatability are comparatively small in a proper laboratory environment, these effects were estimated from the EKS-CZE experiments using conditions such as warming and agitating the sample solution during EKS process. Finally, EKS-CZE was applied to the detection of ions from atmospheric electrolytes in high-purity water exposed to ambient air for 2 h. The microgram per liter levels of anions (chloride, sulfate, nitrate, formate, acetate and lactate) and cations (ammonium, calcium, sodium and magnesium) could be detected using conventional UV detector. PMID:19862736

Xu, Zhongqi; Koshimidzu, Eiji; Hirokawa, Takeshi

2009-10-01

135

An analytical model for laser drilling incorporating effects of exothermic reaction, pulse width and hole geometry  

Microsoft Academic Search

An analytical model is presented which incorporates the effects of using O2 as assist gas. The contribution of the enthalpy of oxidation used in the model was determined experimentally by capturing the ejected melt and measuring the volume percentage of oxidation. The formulation of recoil pressure used in the model takes into account hole diameter and depth, and the associated

G. K. L. Ng; P. L. Crouse; L. Li

2006-01-01

136

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

137

Selenium incorporation into calcite and its effect on crystal growth: An atomic force microscopy study  

E-print Network

Selenium incorporation into calcite and its effect on crystal growth: An atomic force microscopy Crystal growth Selenium The atomic processes leading to calcite growth are still debated. The presence of foreign impurities in solution is known to change the rate of step propagation during growth as well

Montes-Hernandez, German

138

Author's personal copy Selenium incorporation into calcite and its effect on crystal growth: An atomic force  

E-print Network

Author's personal copy Selenium incorporation into calcite and its effect on crystal growth Atomic force microscopy Crystal growth Selenium The atomic processes leading to calcite growth are still during growth as well as the growth mechanism. Among trace elements, selenium, in the form of oxyanions

139

Reactions in glass ionomer cements: V. Effect of incorporating tartaric acid in the cement liquid.  

PubMed

A description is give of the effect on the ASPA cement reaction of tartaric acid incorporated in the cement liquid. Tartaric acid acts as an accelerator that aids in the extraction of ions from the aluminosilicate glass and facilitates their binding to the polyanion chains. Postgelation hardening is significantly increased. Working time is unaffected possibly because cations are initially present as complexes. PMID:187629

Crisp, S; Wilson, A D

1976-01-01

140

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

141

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"

142

Effect of baking on dietary fibre and phenolics of muffins incorporated with apple skin powder  

Microsoft Academic Search

Apple fruit skin, a rich source of dietary fibre and phenolics, is a by-product of apple processing. The effect of baking on the dietary fibre, phenolics, and total antioxidant capacity was investigated using a model system of muffins incorporated with dried apple skin powder (ASP) as a value-added food ingredient. The blanched, dehydrated, and ground ASP contained approximately 41% total

H. P. Vasantha Rupasinghe; Laixin Wang; Gwendolyn M. Huber; Nancy L. Pitts

2008-01-01

143

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

144

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

E-print Network

difference; estrogen; RPL17; RPL37; brain development INTRODUCTION Sexually dimorphic neural systems provideEffects of Estradiol on Incorporation of New Cells in the Developing Zebra Finch Song System17 and RPL37; sex-linked genes) that exhibit greater expression in song control nuclei in juvenile

Wade, Juli

145

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

PubMed

Surface application of broiler litter to no-till cotton could lead to degradation of water quality. Incorporation of broiler litter into the top surface soil (0.05 m) could alleviate this risk. A 2-yr field study was conducted on a silt loam upland soil to determine the effect of incorporation of broiler litter into the soil surface on nutrient and bacterial transport in runoff. The experimental design was a randomized complete block with four treatments and three replications. Treatments were (i) unfertilized control; (ii) surface-appliedbroiler litter at 7.8 Mg ha(-1) without incorporation; (iii) surface-applied broiler litter at 7.8 Mg ha(-1) with immediate incorporation; and (iv) inorganic fertilizer N (urea ammonium nitrate, 32% N) and inorganic fertilizer P (triple superphosphate) at the recommended rate. Phosphorus was surface appliedat 25 kg ha(-1) and N was injected at 101 kg ha(-1) into the soil using a commercial liquid fertilizer applicator. Runoff was collected from small runoff plots (2.4 m by 1.6 m) established at the bottom side of main plots (13.7 m by 6.0 m). Incorporation of broiler litter reduced total N (TN), NO3-N, water soluble P (WSP), and total P (TP) concentrations in runoffby 35, 25, 61, and 64%, respectively, and litter-associated bacteria by two to three orders of magnitude compared with unincorporated treatment. No significant difference in total suspended solids (TSS) in runoffwas obtained between incorporated and unincorporated treatments. Incorporation of broiler litter into the surface soil in the no-till system immediately after application minimized the potential risk for surface nutrient losses and bacteria transport in runoff. PMID:21520764

Adeli, A; Shankle, M W; Tewolde, H; Brooks, J P; Sistani, K R; McLaughlin, M R; Rowe, D E

2011-01-01

146

Electrokinetic phenomena in wavy channels.  

PubMed

Electroosmotic flows are studied in wavy channels by expanding the solution into a double series in terms of the dimensionless amplitudes and of the dimensionless zeta potential for a binary dilute electrolyte. The expansion technique by means of formal calculations is described. Some examples are illustrated and discussed for two- and three-dimensional channels. The importance of the varicose or sinuous character of the channels as well as the role of high frequency roughness are demonstrated. These features may be used for practical purposes in order to amplify or diminish coupling effects in an algebraic way. PMID:20163797

Malevich, Alexander E; Mityushev, Vladimir V; Adler, Pierre M

2010-05-01

147

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

E-print Network

INCORPORATION OF ANALGESICS INTO RODENT EMBRYO TRANSFER PROTOCOLS: ASSESSING THE EFFECTS ON REPRODUCTIVE OUTCOMES A Thesis by HEATHER ANN BURCKHARDT Submitted to the Office of Graduate Studies of Texas A&M University... PROTOCOLS: ASSESSING THE EFFECTS ON REPRODUCTIVE OUTCOMES A Thesis by HEATHER ANN BURCKHARDT Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE...

Burckhardt, Heather Ann

2009-05-15

148

Finite Strain Micromechanical Analysis of Rubber-like Matrix Composites incorporating the Mullins Damage Effect  

Microsoft Academic Search

A model for hyperelastic rubber-like materials that includes the Mullins damage effect has been incorporated with a finite strain micromechanical analysis for composites with periodic microstructures. As a result, it is possible to predict the response of fiber-reinforced rubber-like matrix composites, including the Mullins effect, from the knowledge of the character and properties of the constituents and their volume ratios.

Jacob Aboudi

2009-01-01

149

An improved transmission line laser model for multimode laser diodes incorporating thermal effects  

Microsoft Academic Search

An improved transmission line model to study the thermal effects in semiconductor laser diodes is reported in this paper.\\u000a The temperature effects in the laser characteristics are obtained by incorporating temperature dependent gain and carrier\\u000a density equations for the laser cavity. These primary factors are introduced in the regular transmission line laser model\\u000a to estimate the static and dynamic characteristics

M. Ganesh Madhan; R. Neelakandan

2008-01-01

150

DOES USE-OF-FORCE SIMULATION TRAINING IN CANADIAN POLICE AGENCIES INCORPORATE PRINCIPLES OF EFFECTIVE TRAINING?  

Microsoft Academic Search

Numerous police agencies in Canada incorporate use-of-force simulation training into their overall instructional regime. A prominent theory of learning, known as cognitive load theory, suggests that in order for this training to be effective, instructional methods must facilitate the acquisition and automation of task-relevant schemas without overwhelming the limited processing capacity of the learner. In this article, several instructional effects,

Craig Bennell; Natalie J. Jones; Shevaun Corey

2007-01-01

151

Effects of methionine supplement on methionine incorporation in rat embryos cultured in vitro.  

PubMed

The effect of supplementary L-methionine (Met) on the incorporation of methionine was evaluated in 9.5-day rat conceptuses cultured in vitro. Parallel experiments with L-leucine (Leu) were performed for comparison. Conceptuses were cultured for 24 hr in the presence of 3H-labeled Met or Leu, and the incorporation of radiolabel into the embryo and visceral yolk sac was measured. Supplementary Met proportionately increased the incorporation of Met, but supplementary Leu did not have as great an effect on the incorporation of Leu. A hypothesis is presented to explain these findings. It is proposed that Met, but not Leu, is a rate-limiting nutrient for organogenesis-stage rat embryos cultured in rat serum. The results are also discussed with reference to the established efficacy of supplementary folic acid in decreasing the incidence of neural tube defects in human populations and to claims that Met reverses certain teratogenic phenomena, both in vitro and in vivo. PMID:10413332

Pugarelli, J E; Brent, R L; Lloyd, J B

1999-07-01

152

Electrokinetic flow and electric current in a fibrous porous medium.  

PubMed

An analytical study is presented for the steady electrokinetic flow of electrolyte solutions in the fibrous medium constructed by an ordered array of identical, parallel, charged, circular cylinders. The electric field and/or pressure gradient are applied uniformly in the direction along the axes of the cylinders. The dielectric cylinders may have either a constant surface potential or a constant surface charge density of an arbitrary value. The electric double layer surrounding each cylinder may have an arbitrary thickness relative to the radius of the cylinder. A unit cell model, which allows for the overlap of the double layers of adjacent cylinders, is employed to account for the effect of fiber interactions. The electrostatic potential distribution in the fluid phase is determined by solving the Poisson-Boltzmann equation, and the fluid velocity profile is obtained as the analytical solution of a modified Navier-Stokes equation. Explicit formulas for the flow rate, electroosmotic velocity, electric current, effective electric conductivity, and streaming potential are derived as functions of the porosity of the fiber matrix and other characteristics of the system. The effect of interactions among the cylinders on the fluid velocity and effective conductivity is interesting and can be significant under appropriate conditions. PMID:22369485

Wu, Yi Y; Keh, Huan J

2012-03-22

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

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

155

Research Article Electrokinetic stringency control in self-assembled monolayer-based  

E-print Network

Research Article Electrokinetic stringency control in self-assembled monolayer-based biosensors electrokinetic stringency control approach for a self-assembled monolayer-based electrochemical biosensor toward that electrokinetic stringency control can significantly improve the signal-to-noise ratio of the biosensor

Wong, Pak Kin

156

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

157

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

158

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

PubMed

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

Sant, Vinayak P; Nagarsenker, Mangal S

2011-12-01

159

Effect of isocarbacyclin methyl ester incorporated in lipid microspheres on experimental models of peripheral obstructive disease.  

PubMed

The effect of TTC-909 (isocarbacyclin methyl ester (CAS 88931-51-5, TEI-9090) incorporated into lipid microspheres) on obstruction of the peripheral artery was studied in two different animal models. The first was a peripheral occlusion model induced by intra-arterial injection of sodium laurate in rats. The second was a tail gangrene model induced by subcutaneous injection of both ergotamine and epinephrine in rats. Intravenous bolus-administered TTC-909 at 1.0 microgram/kg resulted in the inhibition of both progression of lesions induced by sodium laurate and the extension of tail gangrene by ergotamine and epinephrine. Moreover, the inhibitory effect of TTC-909 was more potent than that of PGE1 (LM) (prostaglandin E1 incorporated into lipid microspheres). These findings suggested that TTC-909 may be clinically useful for the therapy of peripheral vascular disorders such as thromboangiitis obliterans (TAO) and atherosclerosis obliterans (ASO). PMID:7488320

Murakami, T; Sawada, K; Taneda, K; Hayashi, M; Katsuura, Y; Tanabe, H; Kiyoki, M; Araki, H

1995-09-01

160

Effects of ozone inhalation on polyamine metabolism and tritiated thymidine incorporation into DNA of rat lungs  

Microsoft Academic Search

We examined the effects of low-level ozone (O3) inhalation on polyamine metabolism and tritiated thymidine (3H-TdR) incorporation into DNA in rat lungs. We have also compared the activities of ornithine decarboxylase (ODC), the rate-limiting enzyme of polyamine biosynthesis, and glucose-6-phosphate dehydrogenase (G6PD), the key enzyme of the pentose phosphate cycle and a typical marker of oxidant injury, to assess whether

N. M. Elsayed; A. S. Ellingson; D. F. Tierney; M. G. Mustafa

1990-01-01

161

Modulation of virion incorporation of Ebolavirus glycoprotein: effects on attachment, cellular entry and neutralization.  

PubMed

The filoviruses Ebolavirus (EBOV) and Marburgvirus (MARV) cause severe hemorrhagic fever in humans and are potential agents of biological warfare. The envelope glycoprotein (GP) of filoviruses mediates viral entry into cells and is an attractive target for therapeutic intervention and vaccine design. Here, we asked if the efficiency of virion incorporation of EBOV-GP impacts attachment and entry into target cells and modulates susceptibility to neutralizing antibodies. In order to control the level of EBOV-GP expression, we generated cell lines expressing the GPs of the four known EBOV subspecies in an inducible fashion. Regulated expression of GP on the cell surface allowed production of reporter viruses harboring different amounts of GP. A pronounced reduction of virion incorporation of EBOV-GP had relatively little effect on virion infectivity, suggesting that only a few copies of GP might be sufficient for efficient engagement of cellular receptors. In contrast, optimal interactions with cellular attachment factors like the DC-SIGN protein required incorporation of high amounts of GP. Antibody-mediated neutralization of virions bearing high amounts of GP was slightly more efficient than neutralization of virions harboring low amounts of GP, suggesting that the efficiency of GP incorporation into virions might modulate susceptibility to neutralizing antibodies. Finally, regulated expression of GP in permissive 293 cells did not reduce EBOV-GP-driven infection but diminished vesicular stomatitis virus GP (VSV-G) and amphotropic murine leukemia virus (A-MLV) GP mediated entry in a dose-dependent manner. Therefore, intracellular GP does not seem to downmodulate expression of its receptor(s) but might alter expression and/or function of molecules involved in VSV-G and A-MLV-GP-dependent entry. Our results suggest that the efficiency of virion incorporation of GP could impact EBOV attachment to target cells and might modulate control of viral spread by the humoral immune response. PMID:16777170

Marzi, Andrea; Wegele, Anja; Pöhlmann, Stefan

2006-09-01

162

Analysis of microfluidic flow driven by electrokinetic and pressure forces  

NASA Astrophysics Data System (ADS)

This work presents an analysis of microfluidic flow introduced by mixed electrokinetic force and pressure gradient. Analytical solutions are presented for the case of constant surface heat flux, taking the Joule heating effect into account. The present problem is governed by two scale ratios and the dimensionless source term. The two important ratios are the length scale ratio e (the ratio of Debye length to the tube radius R) and the velocity scale ratio ? (the ratio of the pressuredriven velocity scale for Poiseuille flow to Helmholtz-Smoluchowski velocity for electroosmotic flow). For mixed electroosmotic and pressure-driven flow, the resulting velocity profile is the superimposed effect of both electroosmotic and Poiseuille flow phenomena. It is found that the velocity profile decreases as e increases and the normalized temperature profiles across the tube increases monotonously form the core to the wall. The maximum dimensionless temperature is observed at the wall and the wall temperature increases with increasing Joule heating. Also, the temperature is increased with increasing the value of ? . The fully developed Nusselt number takes the maximum value at the limiting case of ? --> 0 , and then decreases with increasing ? . Moreover, the Nusselt number decreases with ? and then goes asymptotically to the limit of Poiseuille flow as ? --> ? , where the flow is dominated by the pressure force.

Chen, Chien-Hsin

2011-12-01

163

Injection of nutrients and TEAs in clayey soils using electrokinetics  

SciTech Connect

Bioremediation is a cost-effective and attractive technique for cleanup of organic contaminants in high-permeable soils. Difficulties in providing sufficient nutrients and terminal electron acceptors (TEAs) (e.g., nitrate and sulfate) to subsurface contaminant locations preclude its use for in situ biodegradation of organic contaminants in clayey soils. Electrokinetics is shown to be an effective means to inject necessary ionic nutrients and TEAs in clayey soils. Theoretical analysis and experimental results show that electromigration is a significant factor compared with advective transport rate of ions by electroosmosis. Negatively charged nutrients and TEAs could be injected via introducing them at the cathode and vice versa for positively charged ions. Results also indicate that the concentration achievable in the soil depends on the conductivity of the soil and the inlet concentration of the ion to be injected. The higher the soil conductivity and the inlet concentration the higher is the concentration of ionic nutrients and TEAs achievable in the soil. The pH conditions in the soil could be maintained within the range of approximately 6--9 by placing a calcium carbonate layer in the vicinity of the anode.

Thevanayagam, S. [State Univ. of New York, Buffalo, NY (United States). Dept. of Civil, Structural, and Environmental Engineering; Rishindran, T. [Terraprobe, Brampton, Ontario (Canada)

1998-04-01

164

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

165

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

NASA Astrophysics Data System (ADS)

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.; Vinod Kumar, R.; Sudheer, S. K.; Reddy, V. R.; Ganesan, V.; Mahadevan Pillai, V. P.

2012-12-01

166

Determination of food colorants by microemulsion electrokinetic chromatography.  

PubMed

A microemulsion electrokinetic chromatography (MEEKC) method was developed to analyze and detect eight food colorants (tartrazine, fast green FCF, brilliant blue FCF, allura red AC, indigo carmine, sunset yellow FCF, new coccine, and carminic acid), which are commonly used as food additives in various food products. The effects of sodium dodecyl sulfate (SDS) surfactant, organic modifier, cosurfactant, and oil were examined in order to optimize the separation. The amount of organic modifier (acetonitrile) and SDS surfactant were determined as apparent influences on the separation resolution while the type of oil and cosurfactant rarely affected the separation selectivity of the eight colorants. A highly efficient MEEKC separation method, where the eight colorants were separated with baseline resolution within 14 min, was achieved by using a microemulsion solution of pH 2.0 containing 3.31% SDS, 0.81% octane, 6.61% 1-butanol, and 10% acetonitrile. This optimal MEEKC method has a higher separation efficiency and similar detection limit when compared to conventional capillary electrophoresis (CE) method. Furthermore, a sample pretreatment is rarely needed when this MEEKC technique is used to analyze colorants in food products, whereas a suitable sample pretreatment (for example solid-phase extraction) has to be employed prior to CE separation in order to eliminate matrix interferences resulting from the constituents of the food sample. PMID:15669007

Huang, Hsi-Ya; Chuang, Chia-Ling; Chiu, Chen-Wen; Chung, Ming-Che

2005-02-01

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

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

169

ELECTROKINETIC DENSIFICATION OF COAL FINES IN WASTE PONDS  

SciTech Connect

The objective of this research is to apply electrokinetics to remove colloidal coal and mineral particles from coal washing ponds without the addition of chemical additives. Colloidal particles do not settle gravitationally, but because their surfaces are charged one can produce settling by applying an external electric field. Of specific interest is a lake near Centralia, Washington used to wash coal prior to combustion in an electrical power generation facility. Laboratory experiments have demonstrated that electrokinetic treatment is feasible, so this project is examining how to scale up laboratory results to an industrial level. Electrode configurations, power requirements, and system properties are being studied.

E. James Davis

1996-04-01

170

Simulation of electrokinetics at the nanoscale: inversion of selectivity in a bio-nanochannel  

NASA Astrophysics Data System (ADS)

Here we show, combining a simulation and theoretical study, that electrostatic correlations typical of multivalent ions can reverse the selectivity of a biological nanochannel. Our results provide a physical mechanism for a new, experimentally observed phenomenon, namely the inversion of the selectivity of a bacterial porin (the E. Coli OmpF) in presence of divalent and trivalent cations. Also, the differences and similarities between the driving force for this phenomenon and other similar nano and micro-escale electrokinetic effects (e.g. inversion of streaming current in silica nanochannels) are explored.

Aguilella-Arzo, Marcel; Calero, Carles; Faraudo, Jordi

171

Simple procedure for incorporating off-energy-shell effects into energy sudden scaling relations  

SciTech Connect

In this paper, a new approach for incorporating off-energy-shell effects into energy sudden (ES) scaling relations is described. The framework for the new approach is provided by the first order Born approximation which allows for the relating in an approximate fashion of off-energy-shell and on-energy-shell T-matrix elements. The relationship between this approach and a former procedure is discussed. Application of the off-shell corrected ES relation is made to the vibrational-rotational scattering of He--H/sub 2/.

Eno, L.

1984-05-01

172

A Detailed Circuit Model for Semiconductor Optical Amplifier Incorporating Thermal Effects  

NASA Astrophysics Data System (ADS)

A detailed circuit model for semiconductor optical amplifier, which incorporates thermal and spectral behavior, is reported. The rate equations of semiconductor optical amplifier form the basis for the equivalent circuit development. The circuit is simulated for static and dynamic conditions and its performance as amplifier, modulator and detector are evaluated. Further, thermal effects on the characteristics of SOA are determined. The SOA performance is studied in the temperature range of 283-343 K and the results are found to agree well with the literature.

Rekha, E.; Madhan, M. Ganesh

2014-09-01

173

Assessment of anecic behavior in selected earthworm species: Effects on wheat seed burial, seedling establishment, wheat growth and litter incorporation  

Microsoft Academic Search

Anecic earthworm species function as ecosystem engineers by structuring the soil environment, incorporating large amounts of litter and seeds into soil and, thereby influence the composition of plant communities. The aim of the present greenhouse experiment was to investigate the effects of three apparently anecic earthworm species on wheat seed burial, seedling establishment, wheat growth and litter incorporation. The three

Nico Eisenhauer; Sven Marhan; Stefan Scheu

2008-01-01

174

The effect of incorporation of a Brazilian water treatment plant sludge on the properties of ceramic materials  

Microsoft Academic Search

We evaluated the feasibility of incorporating sludge from decantation ponds of a water treatment plant (WTP) into a ceramic body used in ceramic brick manufacturing. The sludge grain-size distribution (silt, sand and clay) and the effects of its incorporation on the properties of the ceramic body were studied. Samples were collected during a period of ten months. The chemical and

S. R. Teixeira; G. T. A. Santos; A. E. Souza; P. Alessio; S. A. Souza; N. R. Souza

2011-01-01

175

Experimental and theoretical basis of electrokinetic phenomena in rock-water systems and its applications to geophysics  

Microsoft Academic Search

The z potentials and the streaming potential coefficients of silicate mineral-water and rock-water systems were measured for purposes of estimating the magnitude of electrokinetic effects induced by water diffusion in the earth's interior. In rock-water systems the adsorption reaction of H+ at a solid surface is proved to be a main factor determining the z potential. For typical crustal rocks

Tsuneo Ishido; Hitoshi Mizutani

1981-01-01

176

Emission Frequency Modulation by Confinement Effect: Rhodamine-B Incorporated Within a Dendritic Structure  

NASA Astrophysics Data System (ADS)

Dendrimers are nanometric-size macromolecules with a regular tree-dimensional like array of branch units. Within this macromolecular structure it is possible to encapsulate a variety of guest molecules. In this paper we show that the photophysical properties of Rhodamine-B encapsulated into the dendritic box can be easily modulated by the innovative quantum confinement effect. The emission frequencies of this organic dye incorporated within the dendritic structure can effectively be red shifted with respect to their emission in solution and contrary to other confined spaces of considerable hardness, the magnitude of this shifting can be regulated under appropriate experimental conditions. This effect could have unprecedented applications in the development of supramolecular devices relating to the frequency tuning of organic laser dyes.

Márquez, Francisco; José Sabater, María

2005-01-01

177

Contrasting effects of arachidonic acid and docosahexaenoic acid membrane incorporation into cardiomyocytes on free cholesterol turnover.  

PubMed

The preservation of a constant pool of free cholesterol (FC) is critical to ensure several functions of cardiomyocytes. We investigated the impact of the membrane incorporation of arachidonic acid (C20:4 ?6, AA) or docosahexaenoic acid (C22:6 ?3, DHA) as ?6 or ?3 polyunsaturated fatty acids (PUFAs) on cholesterol homeostasis in primary cultures of neonatal rat cardiac myocytes. We measured significant alterations to the phospholipid FA profiles, which had markedly different ?6/?3 ratios between the AA and DHA cells (13 vs. 1). The AA cells showed a 2.7-fold lower cholesterol biosynthesis than the DHA cells. Overall, the AA cells showed 2-fold lower FC masses and 2-fold higher cholesteryl ester masses than the DHA cells. The AA cells had a lower FC to phospholipid ratio and higher triglyceride levels than the DHA cells. Moreover, the AA cells showed a 40% decrease in ATP binding cassette transporter A1 (ABCA1)-mediated and a 19% decrease in ABCG1-mediated cholesterol efflux than the DHA cells. The differences in cholesterol efflux pathways induced by AA or DHA incorporation were not caused by variations in ABCs transporter expression and were reduced when ABC transporters were overexpressed by exposure to LXR/RXR agonists. These results show that AA incorporation into cardiomyocyte membranes decreased the FC turnover by markedly decreasing the endogenous cholesterol synthesis and by decreasing the ABCA1- and ABCG1-cholesterol efflux pathways, whereas DHA had the opposite effects. We propose that these observations may partially contribute to the beneficial effects on the heart of a diet containing a high ?3/?6 PUFA ratio. PMID:25019598

Doublet, Aline; Robert, Véronique; Vedie, Benoît; Rousseau-Ralliard, Delphine; Reboulleau, Anne; Grynberg, Alain; Paul, Jean-Louis; Fournier, Natalie

2014-10-01

178

Effects of ozone inhalation on polyamine metabolism and tritiated thymidine incorporation into DNA of rat lungs  

SciTech Connect

We examined the effects of low-level ozone (O3) inhalation on polyamine metabolism and tritiated thymidine (3H-TdR) incorporation into DNA in rat lungs. We have also compared the activities of ornithine decarboxylase (ODC), the rate-limiting enzyme of polyamine biosynthesis, and glucose-6-phosphate dehydrogenase (G6PD), the key enzyme of the pentose phosphate cycle and a typical marker of oxidant injury, to assess whether ODC can serve as a sensitive marker of O3 effects on the lung. We exposed 90-day-old male specific-pathogen-free Sprague-Dawley rats to either 0.45 +/- 0.05 ppm (882 +/- 98 micrograms/m3) O3 or filtered room air continuously for 3 days. After exposure, the rats were terminated and the lungs examined for enzyme activities, polyamine contents, DNA content, and 3H-TdR incorporation. We found that in exposed rats, the enzyme activities were significantly increased (p less than 0.05) relative to air controls. G6PD, 25%, ODC, 147%, and S-adenosylmethionine decarboxylase (AdoMet DC), 86%. Polyamine contents were also affected by O3; putrescine increased 80%, p less than 0.05, spermidine did not change, and spermine decreased 23%, p less than 0.05. 3H-TdR incorporation into DNA was significantly elevated, 155%, p less than 0.001, after O3 exposure while total lung DNA content remained unchanged. The concomitant and large increase in ODC activity (reflecting polyamine metabolism) and DNA labeling (reflecting DNA synthesis and/or repair), indicates a strong correlation between the two and suggests that polyamine metabolism may play an important role in the accelerated cell proliferation associated with O3 injury. Moreover, the greater increase in lung ODC activity compared to other enzymes offers a sensitive marker of the lung response to inhaled O3.

Elsayed, N.M.; Ellingson, A.S.; Tierney, D.F.; Mustafa, M.G. (Univ. of California, Los Angeles (USA))

1990-01-01

179

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

180

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

PubMed Central

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

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

2012-01-01

181

Electro-kinetics of charged-sphere suspensions explored by integral low-angle super-heterodyne laser Doppler velocimetry  

NASA Astrophysics Data System (ADS)

We investigated the flow behaviour of colloidal charged-sphere suspensions using a newly designed integral low-angle super-heterodyne laser Doppler velocimetry instrument, which combines the advantages of several previous approaches. Sample conditions ranged from strong electrostatic interactions with pronounced short-range order to individual particles with no spatial correlations. The obtained power spectra correspond to diffusion broadened velocity distributions across the complete sample cross section. The excellent performance of the instrument is highlighted in detail by the example of electro-kinetic flow of suspensions in a closed cell of a rectangular cross section. We demonstrate the excellent performance of our approach with the example of electro-phoretic-electro-osmotic experiments, showing that a comprehensive flow characterization becomes possible by analysing the measured electro-kinetic mobilities, the flow-profile, an effective diffusion coefficient and the integrated scattering density. We briefly discuss present limitations, possible extensions and interesting applications in other fields.

Palberg, Thomas; Köller, Tetyana; Sieber, Bastian; Schweinfurth, Holger; Reiber, Holger; Nägele, Gerhard

2012-11-01

182

Micellar electrokinetic capillary chromatography analysis of water-soluble vitamins  

Microsoft Academic Search

This paper describes the development of an electrophoretic method used to analyse seven water-soluble vitamins, and its use in the analysis of pharmaceutical formulations. Thiamine, nicotinamide, nicotinic acid, pyridoxine, ascorbic acid, folic acid and riboflavin were separated from one another in 7min by micellar electrokinetic capillary chromatography using a carrier containing sodium dodecyl sulphate as surfactant, and were subsequently detected

Domingo Blanco Gomis; Luis Laviana González; Dolores Gutiérrez Álvarez

1999-01-01

183

Progress in Electrogravitics and Electrokinetics for Aviation and Space Travel  

Microsoft Academic Search

An analysis of the 87-year old science of electrogravitics (or electrogravity) necessarily includes an analysis of electrokinetics. Electrogravitics is most commonly associated with 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 \\

Thomas F. Valone

184

ELECTROKINETIC DENSIFICATION OF COAL FINES IN WASTE PONDS  

Microsoft Academic Search

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

E. James Davis

1999-01-01

185

Electrokinetic densification of coal fines in waste ponds.  

National Technical Information Service (NTIS)

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 spe...

E. J. Davis

1999-01-01

186

Binary electrokinetic separation of target DNA from background DNA primers  

Microsoft Academic Search

This report contains the summary of LDRD project 91312, titled ''Binary Electrokinetic Separation of Target DNA from Background DNA Primers''. This work is the first product of a collaboration with Columbia University and the Northeast BioDefense Center of Excellence. In conjunction with Ian Lipkin's lab, we are developing a technique to reduce false positive events, due to the detection of

Conrad D. James; Mark Steven Derzon

2005-01-01

187

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...

188

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

189

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

E-print Network

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

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

2014-01-01

190

Simple form of multimode laser diode rate equations incorporating the band filling effect.  

PubMed

To derive a simple form of the multimode laser diode rate equations incorporating the band filling effect, the laser diode gain in the direct bandgap model is introduced into the conventional multimode laser diode rate equations. By numerically examining each modal gain under the gain-switching condition, it is found that both the differential gain coefficient and the carrier density at transparency show an approximately linear dependency on the oscillation frequency. As a result, it is possible to derive a simple form of the multimode laser diode rate equations with linearized gain, which can be used to simulate the behaviors of a gain-switched laser diode characterized by the band filling effect, in both the multimode and single-mode oscillation cases. PMID:21369126

Wada, Kenji; Yoshioka, Hiroyuki; Zhu, Jiaxun; Matsuyama, Tetsuya; Horinaka, Hiromichi

2011-02-14

191

Electrokinetic remediation of heavy metal-contaminated soils under reducing environments  

SciTech Connect

This paper describes the migration of hexavalent chromium, Cr(VI), nickel, Ni(II), and cadmium, Cd(II), in clayey soils that contain different reducing agents under an induced electric potential. Bench-scale electrokinetic experiments were conducted using two different clays, kaolin and glacial till, both with and without a reducing agent. The reducing agent used was either humic acid, ferrous iron, or sulfide, in a concentration of 1000 mg/kg. These soils were then spiked with Cr(VI), Ni(II), and Cd(II) in concentrations of 1000, 500 and 250 mg/kg, respectively, and tested under an induced electric potential of 1 VDC/cm for a duration of over 200 h. The reduction of chromium from Cr(VI) to Cr(III) occurred prior to electrokinetic treatment. The extent of this Cr(VI) reduction was found to be dependent on the type and amount of reducing agents present in the soil. The maximum reduction occurred in the presence of sulfides, while the minimum reduction occurred in the presence of humic acid. The concentration profiles in both soils following electrokinetic treatment showed that Cr(VI) migration was retarded significantly in the presence of sulfides due both to the reduction of Cr(VI) to Cr(III) as well as an increase in soil pH. This low migration of chromium is attributed to: (1) migration of Cr(VI) and the reduced Cr(III) fraction in opposite directions, (2) low Cr(III) migration due to adsorption and precipitation in high pH regions near the cathode in kaolin and throughout the glacial till, and (3) low Cr(VI) migration due to adsorption in the pH regions near the anode in both soils. Ni(II) and Cd(II) migrated towards the cathode in kaolin; however, the migration was significantly retarded in the presence of sulfides due to increased pH through most of the soil. Initial high pH conditions within the glacial till resulted in Ni(II) and Cd(II) precipitation, so the effects of reducing agents were inconsequential. Overall, this study demonstrated that the reducing agents, particularly sulfides, in soils may affect redox chemistry and soil pH, ultimately affecting the electrokinetic remediation process.

Reddy, K.R.; Chinthamreddy, S. (Univ. of Illinois, Chicago, IL (United States). Dept. of Civil and Materials Engineering)

1999-01-01

192

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

193

Enhancement of in vivo anticancer effects of cisplatin by incorporation inside single-wall carbon nanohorns.  

PubMed

Cisplatin (CDDP) was incorporated inside single-wall carbon nanohorns with holes opened (SWNHox) by a nanoprecipitation method that involved dispersion of CDDP and SWNHox in a solvent followed by the solvent evaporation. The incorporated CDDP quantity increased from the previously reported value of 15 to 46%, and the total released quantity of CDDP also increased from 60 to 100% by changing the solvent from dimethylformamide to water. Concurrently, in vitro anticancer efficiency of CDDP@SWNHox increased to 4-6 times greater than that of the intact CDDP. In vivo, CDDP@SWNHox intratumorally injected to transplanted tumors of mice suppressed the tumor growth more than the intact CDDP. We observed that CDDP@SWNHox adhered to the cell surfaces in vitro and stayed within the tumor tissues in vivo. Therefore, we think that the CDDP released from SWNHox realized high concentrations locally at the cells in vitro and in the tissues in vivo and could efficiently attack the tumor cells. We also found that SWNHox itself had an in vivo anticancer effect, which might increase the anticancer activities of CDDP@SWNHox. PMID:19206452

Ajima, Kumiko; Murakami, Tatsuya; Mizoguchi, Yoshikazu; Tsuchida, Kunihiro; Ichihashi, Toshinari; Iijima, Sumio; Yudasaka, Masako

2008-10-28

194

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

195

Electrokinetic remediation of six emerging organic contaminants from soil.  

PubMed

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

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

2014-12-01

196

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

PubMed

Low-density polyethylene (LDPE)/polypropylene (PP) blend films in various blending ratios containing 3000?mg??kg?¹ of tocopherol were manufactured by an extrusion process. Tocopherol release properties were characterised and correlated with antioxidant effectiveness in retarding the oxidation of linoleic acid contacting the films at 40°C. The conditions without tocopherol (control) and with instant tocopherol addition corresponding to the amount included in the films were also prepared and compared with the film-contacting solutions. The effect of tocopherol inclusion and the blending ratio on their physical properties was also examined. A wide range of tocopherol diffusivity in 6.6?×?10?¹?-4.6?×?10?¹?m²?s?¹ were obtained by blend films. As PP content increases, the diffusivity decreased sharply at the beginning and levelled off later. The slower release of tocopherol in LDPE/PP blend films corresponding to lower tocopherol diffusivity retained the higher tocopherol concentration in the linoleic acid system providing better antioxidant effectiveness of the extended induction period in oxidation. The tocopherol inclusion reduced tensile strength and transparency significantly in an affordable range with higher tensile strength given by a higher PP ratio. LDPE/PP blending can be a useful tool to modulate the release profile of tocopherol and thus the antioxidant effectiveness of the tocopherol-incorporated antioxidant packaging film. PMID:22257167

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

2012-01-01

197

Incorporation of 3D Shortwave Radiative Effects within the Weather Research and Forecasting Model  

SciTech Connect

A principal goal of the Atmospheric Radiation Measurement (ARM) Program is to understand the 3D cloud-radiation problem from scales ranging from the local to the size of global climate model (GCM) grid squares. For climate models using typical cloud overlap schemes, 3D radiative effects are minimal for all but the most complicated cloud fields. However, with the introduction of ''superparameterization'' methods, where sub-grid cloud processes are accounted for by embedding high resolution 2D cloud system resolving models within a GCM grid cell, the impact of 3D radiative effects on the local scale becomes increasingly relevant (Randall et al. 2003). In a recent study, we examined this issue by comparing the heating rates produced from a 3D and 1D shortwave radiative transfer model for a variety of radar derived cloud fields (O'Hirok and Gautier 2005). As demonstrated in Figure 1, the heating rate differences for a large convective field can be significant where 3D effects produce areas o f intense local heating. This finding, however, does not address the more important question of whether 3D radiative effects can alter the dynamics and structure of a cloud field. To investigate that issue we have incorporated a 3D radiative transfer algorithm into the Weather Research and Forecasting (WRF) model. Here, we present very preliminary findings of a comparison between cloud fields generated from a high resolution non-hydrostatic mesoscale numerical weather model using 1D and 3D radiative transfer codes.

O'Hirok, W.; Ricchiazzi, P.; Gautier, C.

2005-03-18

198

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

199

Electrokinetic remediation of organochlorines in soil: enhancement techniques and integration with other remediation technologies.  

PubMed

Electrokinetic remediation has been increasingly used in soils and other matrices for numerous contaminants such as inorganic, organic, radionuclides, explosives and their mixtures. Several strategies were tested to improve this technology effectiveness, namely techniques to solubilize contaminants, control soil pH and also couple electrokinetics with other remediation technologies. This review focus in the experimental work carried out in organochlorines soil electroremediation, aiming to systemize useful information to researchers in this field. It is not possible to clearly state what technique is the best, since experimental approaches and targeted contaminants are different. Further research is needed in the application of some of the reviewed techniques. Also a number of technical and environmental issues will require evaluation for full-scale application. Removal efficiencies reported in real contaminated soils are much lower than the ones obtained with spiked kaolinite, showing the influence of other factors like aging of the contamination and adsorption to soil particles, resulting in important challenges when transferring technologies into the field. PMID:22386462

Gomes, Helena I; Dias-Ferreira, Celia; Ribeiro, Alexandra B

2012-06-01

200

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

PubMed

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

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

2014-11-01

201

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

SciTech Connect

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

Sepaniak, M.J.

1993-10-01

202

Methods for incorporating effects of LWR coolant environment into ASME code fatigue evaluations.  

SciTech Connect

The ASME Boiler and Pressure Vessel Code provides rules for the construction of nuclear power plant components. Appendix I to Section HI of the Code specifies design fatigue curves for structural materials. However, the effects of light water reactor (LWR) coolant environments are not explicitly addressed by the Code design curves. Recent test data illustrate potentially significant effects of LWR environments on the fatigue resistance of carbon and low-alloy steels and austenitic stainless steels (SSs). Under certain loading and environmental conditions, fatigue lives of carbon and low-alloy steels can be a factor of {approx}70 lower in an LWR environment than in air. These results raise the issue of whether the design fatigue curves in Section III are appropriate for the intended purpose. This paper presents the two methods that have been proposed for incorporating the effects of LWR coolant environments into the ASME Code fatigue evaluations. The mechanisms of fatigue crack initiation in carbon and low-alloy steels and austenitic SSs in LWR environments are discussed.

Chopra, O. K.

1999-04-15

203

Effect of growth pressure on indium incorporation during the growth of InGaN by MOCVD  

Microsoft Academic Search

The effect of the growth pressure on the In incorporation in InGaN thin films, grown by metalorganic chemical vapor deposition\\u000a (MOCVD) have been investigated. The InGaN thin films were grown by varying the growth pressures, while maintaining all other\\u000a growth parameters constant. Photoluminescence and high resolution x-ray diffraction (XRD) measurements showed that the In\\u000a incorporation in the InGaN thin film

Dong-Joon Kim; Yong-Tae Moon; Keun-Man Song; In-Hwan Lee; Seong-Ju Park

2001-01-01

204

Local reduced-density-matrix-functional theory: Incorporating static correlation effects in Kohn-Sham equations  

NASA Astrophysics Data System (ADS)

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

Lathiotakis, Nektarios N.; Helbig, Nicole; Rubio, Angel; Gidopoulos, Nikitas I.

2014-09-01

205

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

206

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

207

Effects of toxic substances on natural bacterial assemblages determined by means of ( sup 3 H)thymidine incorporation  

SciTech Connect

The effects of 3,5-dichlorophenol, 2,4-dinitrophenol, and potassium dichromate on natural bacterial assemblages were examined by means of ({sup 3}H)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 ({sup 3}H)thymidine incorporation and in ({sup 3}H)thymidine incorporation per cell. The concentrations that inhibited ({sup 3}H)thymidine incorporation by 50% ranged from 3 to 11 mg liter{sup {minus}1} for 3,5-dichlorophenol, 5 to 10 mg liter{sup {minus}1} for 2,4-dinitrophenol, and 21 to 123 mg liter{sup {minus}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 ({sup 3}H) leucine incorporation into bacterial protein were similar or larger than those obtained from ({sup 3}H) thymidine incorporation. (III) Two to four hours of exposure to the toxicants was necessary before stable maximum effects were found in ({sup 3}H)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.

Riemann, B., Lindgaard-Jorgensen, P. (The Water Quality Institute, Horsholm (Denmark))

1990-01-01

208

Numerical simulation of electrokinetic potentials associated with subsurface fluid flow  

SciTech Connect

A postprocessor has been developed to calculate space/time distributions of electrokinetic potentials resulting from histories of underground conditions (pressure, temperature, flowrate, etc.) computed by multi-phase multicomponent unsteady multidimensional geothermal reservoir simulations. Electrokinetic coupling coefficients are computed by the postprocessor using formulations based on experimental work reported by Ishido and Mzutani (1981). The purpose of the present study is to examine whether or not self-potential anomalies actually observed in real geothermal fields are consistent with quantitative mathematical reservoir models constructed using conventional reservoir engineering data. The most practical application of the postprocessor appears to be modeling self-potential changes induced by field-wide geothermal fluid production. Repeat self-potential surveying appears to be promising as a geophysical monitoring technique to provide constraints on mathematical reservoir models, in a similar fashion to the use of repeat microgravity surveys.

Ishido, Tsuneo; Pritchett, John W.

1996-01-24

209

ELECTROKINETIC WAVE PHENOMENA IN FLUID-SATURATED GRANULAR MEDIA  

SciTech Connect

Electrokinetic (EK) phenomena in sediments arise from relative fluid motion in the pore space, which perturbs the electrostatic equilibrium of the double layer at the grain surface. We have developed EK techniques in the laboratory to monitor acoustic wave propagation in electrolyte-saturated, unconsolidated sediments. Our experimental results indicate that as an acoustic wave travels through electrolyte-saturated sand, it can generate electric potentials greater than 1 mV. A careful study of these potentials was performed using medium-grain sand and loose glass microspheres for a range of pore fluid salinities and ultrasonic frequencies. Experimental results are also shown to compare well with numerical and analytical modeling based on the coupled electrokinetic-Biot theory developed by Pride (1994).

Block, G

2005-03-29

210

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

211

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

212

Impurity profiling of atropine sulfate by microemulsion electrokinetic chromatography  

Microsoft Academic Search

An oil-in-water microemulsion electrokinetic chromatography (MEEKC) method has been developed and validated for the determination of atropine, its major degradation products (tropic acid, apoatropine and atropic acid) and related substances from plants material (noratropine, 6-hydroxyhyoscyamine, 7-hydroxyhyoscyamine, hyoscine and littorine).Separation of atropine and all impurities was optimized by varying the voltage, the nature of the oil droplet and the buffer, as

Yaser Bitar; Ulrike Holzgrabe

2007-01-01

213

Electrokinetic dewatering of Turkish glass sand plant tailings  

Microsoft Academic Search

In this study, the dewatering of glass sand plant tailings from Mersin, Turkey was investigated using an electrokinetic technique. The particle size (d80) of the solid waste material tested was less than 0.020mm and consisted mainly of silica, orthoclase, alumina, potassium and iron oxides. In current plant practice, Larox high-pressure filters are used to produce a filter cake containing 22–25%

O. Bayat; O. Kilic; B. Bayat; M. Anil; H. Akarsu; C. Poole

2006-01-01

214

Electrokinetic pumping of liquid propellants for small satellite microthruster applications  

Microsoft Academic Search

For most orbital maneuvers, small satellites weighing less than 10kg require propulsion systems capable of producing thrust in the micro-Newton to milli-Newton force range. At this scale, electrokinetic (EK) pumping offers a method to precisely meter liquid propellants under purely electrical control at pressures and flow rates well-suited for microthruster applications. After exploring a variety of materials and surface treatments

Kamlesh D. Patel; Michael S. Bartsch; Matthew H. McCrink; Jennifer S. Olsen; Bruce P. Mosier; Robert W. Crocker

2008-01-01

215

Electrokinetically Pumped Liquid Propellant Microthrusters for Orbital Station Keeping  

Microsoft Academic Search

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

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

2007-01-01

216

A simple method to incorporate the effects of an RF shield into RF resonator analysis for MRI applications  

Microsoft Academic Search

A simple but effective method is proposed to incorporate the effects of a radiofrequency (RF) shield into the analysis of RF resonators for magnetic resonance imaging (MRI) applications. It Is shown that the method can predict the resonant frequencies of RF resonators within 5% of the measured values.

Jianming Jin; Richard L. Magin; Gary Shen; Thomas Perkins

1995-01-01

217

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

218

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

219

Effect of flaxseed flour incorporation on the physical properties and consumer acceptability of cereal bars.  

PubMed

Extensive research has revealed numerous nutritional and health benefits of flaxseed due primarily to its nutrients content. The objective of this study was to evaluate the effect of flaxseed flour addition on the physical and sensory characteristics of cereal bars. Four formulations of the flaxseed cereal bars were prepared by partially replacing oats with flaxseed flour added at levels of 0 (control), 6%, 12% and 18%. There were no significant differences (p?>?0.05) in water activity, moisture and firmness values between the flaxseed bars and control. Flaxseed addition significantly (p??0.05) between the 12% flax cereal bars and the control with respect to sensory attributes and overall acceptability. The overall acceptability for both 12% flax bars and the control was in between 'like moderately' and 'like slightly' on the 9-point hedonic scale. The overall acceptability was most highly correlated with flavor acceptability for both control (r?=?0.80) and 12% flax (r?=?0.82) cereal bars. Flaxseed bars provided 12% dietary fiber of the daily recommended value. These results indicated that flaxseed flour incorporation up to 12% substantially enhanced the nutritional qualities of the cereal bars without affecting their sensory and quality properties. PMID:23733813

Khouryieh, H; Aramouni, F

2013-12-01

220

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

221

Effects of nisin-incorporated films on the microbiological and physicochemical quality of minimally processed mangoes.  

PubMed

The aim of this study is to examine the effects of nisin-incorporated cellulose films on the physicochemical and microbiological qualities of minimally processed mangoes. The use of antimicrobial films did not affect the physicochemical characteristics of mangoes and showed antimicrobial activity against Staphylococcus aureus, Listeria monocytogenes, Alicyclobacillus acidoterrestris and Bacillus cereus. The mango slices were inoculated with S. aureus and L. monocytogenes (10(7)CFU/g), and the viable cell numbers remained at 10(5) and 10(6)CFU/g, respectively, after 12days. In samples packed with antimicrobial films, the viable number of L. monocytogenes cells was reduced below the detection level after 4days. After 6days, a reduction of six log units was observed for S. aureus. In conclusion, nisin showed antimicrobial activity in mangoes without interfering with the organoleptic characteristics of the fruit. This result suggests that nisin could potentially be used in active packing to improve the safety of minimally processed mangoes. PMID:23673058

Barbosa, Ana Andréa Teixeira; Silva de Araújo, Hyrla Grazielle; Matos, Patrícia Nogueira; Carnelossi, Marcelo Augusto Guitierrez; Almeida de Castro, Alessandra

2013-06-17

222

Theoretical implications of incorporating relative biological effectiveness into radiobiological equivalence relationships  

PubMed Central

Objective: Earlier radiobiological equivalence relationships as derived for low-linear energy transfer (LET) radiations are revisited in the light of newer radiobiological models that incorporate an allowance for relative biological effectiveness (RBE). Methods: Linear-quadratic (LQ) radiobiological equations for calculating biologically effective dose at both low- and high-LET radiations are used to derive new conditions of equivalence between a variety of radiation delivery techniques. The theoretical implications are discussed. Results: The original (pre-LQ) concept of equivalence between fractionated and continuous radiotherapy schedules, in which the same physical dose is delivered in each schedule, inherently assumed that low-LET radiation would be used in both schedules. LQ-based equivalence relationships that allow for RBE and are derived assuming equal total physical dose between schedules are shown to be valid only in limited circumstances. Removing the constraint of equality of total physical dose allows the identification of more general (and more practical) relationships. Conclusion: If the respective schedules under consideration for equivalence both involve radiations of identical LET, then the original equivalence relationships remain valid. However, if the compared schedules involve radiations of differing LET, then new (and more restrictive) equivalence relationships are found to apply. Advances in knowledge: Theoretically derived equivalence relationships based on the LQ model provide a framework for the design and intercomparison of a wide range of clinical techniques including those involving high- and/or low-LET radiations. They also provide a means of testing for the validity of variously assumed tissue repair kinetics. PMID:23385996

Dale, R G

2013-01-01

223

The effects of music therapy incorporated with applied behavior analysis verbal behavior approach for children with autism spectrum disorders.  

PubMed

This study compared a common form of Applied Behavior Analysis Verbal Behavior (ABA VB) approach and music incorporated with ABA VB method as part of developmental speech-language training in the speech production of children with Autism Spectrum Disorders (ASD). This study explored how the perception of musical patterns incorporated in ABA VB operants impacted the production of speech in children with ASD. Participants were 22 children with ASD, age range 3 to 5 years, who were verbal or pre verbal with presence of immediate echolalia. They were randomly assigned a set of target words for each of the 3 training conditions: (a) music incorporated ABA VB, (b) speech (ABA VB) and (c) no-training. Results showed both music and speech trainings were effective for production of the four ABA verbal operants; however, the difference between music and speech training was not statistically different. Results also indicated that music incorporated ABA VB training was most effective in echoic production, and speech training was most effective in tact production. Music can be incorporated into the ABA VB training method, and musical stimuli can be used as successfully as ABA VB speech training to enhance the functional verbal production in children with ASD. PMID:22506303

Lim, Hayoung A; Draper, Ellary

2011-01-01

224

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

NASA Technical Reports Server (NTRS)

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

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

1984-01-01

225

The Effect of Zr Incorporation Caused by Ball Abrasion in a Milled Fe-Y2O3 Model Alloy  

NASA Astrophysics Data System (ADS)

Y-O nanoparticles which are homogeneously distributed in the matrix can improve the thermal properties of steels. Several studies of mechanically alloyed steels showed that especially Y-Ti-O particles can cause a further improvement of the mechanical properties at elevated temperatures. It is also assumed that an addition of Zr instead of Ti may have a similar or even stronger effect. This study presents a new way of producing nanostructured ferritic alloys as Zr is incorporated by attrition of yttrium-stabilized zirconia balls during milling. Additionally, the effect of Zr incorporation is demonstrated as well as the particle size distribution of the Y-Zr-O nanoparticles analyzed by transmission electron microscopy. This is compared to a specimen milled with common steel balls. Atom probe tomography and transmission electron microscopy show that the incorporated zirconia lowers the minimum particle size and causes a finer particle distribution. This particle refinement causes a higher hardness after hipping.

Ressel, Gerald; Primig, Sophie; Leitner, Harald

2013-10-01

226

Effect of fO2 on the incorporation and diffusivity of Li in olivine  

NASA Astrophysics Data System (ADS)

Over the last decade the geochemical behaviour of Li has become of special interest since it was speculated that Li stable isotopes could be a promising tracer for subduction zone processes. However, there have been many studies of natural samples but our experimental and theoretical basis for interpreting these data is still lacking. Two diffusion mechanisms were identified for Li in olivine [1]. Their contribution to the net flux of Li in olivine depends on the vacancy concentration on the metal sites, which is sensitive to the fO2. Therefore we have studied the effect of fO2 on Li solubility and diffusion in olivine. Experimental approach: thin plates of crushed, natural olivine single crystals were embedded into two different kind of powders, ground plagioclase with about 2.5 ppm Li or a pre-annealed powder mixture of San Carlos olivine and isotopically enriched Li. All runs were performed in a gas-mixing furnace with fO2 controlled by flowing CO/CO2 mixture. In each run we simultaneously annealed about 100 micrometer-sized samples of Pakistan olivine and San Carlos olivine. In addition we have added to each run a mm sized crystallographically oriented parallelepiped of San Carlos olivine. For each powder reservoir we have performed a set of three anneals at 1200 C and different fO2. Cross sections of the run products were polished and analyzed with LA-ICP-MS. Results: In all cases the Li isotopes and concentrations were homogeneous in the 100 micrometer sized grains with one exception, the experiment at 1.e-10 bar with the highly enriched Li reservoir. The final Li concentration was slightly lower in the Pakistan than San Carlos olivine and was much lower in general if buffered by the plagioclase powder. Most importantly, the Li concentration increased systematically with increasing oxygen fugacity, indicating that the incorporation of Li in olivine is fO2 dependent. The mm-sized, oriented crystal was in most cases zoned and the extent of zoning depends on the diffusion direction. In addition the profiles became systematically longer with decreasing fugacity and at the most reducing conditions the crystal was almost homogenous. However, the isotopes were in all cases completely homogenized and equilibrated with the isotopically enriched reservoir. Thermodynamic model: We extended the quantitative point defect model for olivine [2] and reproduced the effect of fO2 on the solubility of Li when we assume it is mainly on the metal site and charge balanced by the formation of Fe3+ on the metal site. Conclusions: Our results strongly indicate that incorporation of Li is dependent on the fO2, less dependent on the trace element content. Diffusion of Li in olivine is anisotropic and dependent on fO2. Our quantitative point defect model for olivine underpins the experimental results. This will allow us to develop a multi-component diffusion model considering relevant point defects, e.g. Fe3+ and metal vacancies. Such a model will hopefully help us to simulate diffusion of Li at various natural circumstances including fO2 as a critical parameter. References: [1] Dohmen et al. (2010) Geochim Cosmochim Acta 74, 274-292; [2] Dohmen and Chakraborty (2007), Phys Chem Minerals 34, 597- 598.

Dohmen, R.; Coogan, L. A.

2012-12-01

227

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

PubMed

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

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

2011-01-01

228

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.

229

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

Microsoft Academic Search

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

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

2003-01-01

230

Effects of low intensity pulsed ultrasound with and without increased cortical porosity on structural bone allograft incorporation  

Microsoft Academic Search

BACKGROUND: Though used for over a century, structural bone allografts suffer from a high rate of mechanical failure due to limited graft revitalization even after extended periods in vivo. Novel strategies that aim to improve graft incorporation are lacking but necessary to improve the long-term clinical outcome of patients receiving bone allografts. The current study evaluated the effect of low-intensity

Brandon G Santoni; Nicole Ehrhart; A Simon Turner; Donna L Wheeler

2008-01-01

231

Effects of nitrogen-incorporated interface layer on the transient characteristics of hafnium oxide n-metal-oxide-semiconductor field-effect transistors  

NASA Astrophysics Data System (ADS)

In this letter, we present the effects of the nitrogen-incorporated interface on threshold voltage shift (?Vth), which was induced by charge trapping and detrapping in hafnium oxide (HfO2) n-metal-oxide-semiconductor field-effect transistors. Under the various gate voltage conditions, the nitrogen-incorporated interface showed a smaller ratio of interface charge density to total charge density (Nit/Ntotal) due to its thinner interface thickness and lower energy band offset. In addition, the degradations of the interface quality and the mobility under the stress condition were less severe for the nitrogen-incorporated interface devices.

Kang, Chang Yong; Rhee, Se Jong; Choi, Chang Hwan; Kang, Chang Seok; Choi, Rino; Akbar, Mohammad S.; Zhang, Manhong; Krishnan, Siddarth A.; Lee, Jack C.

2005-03-01

232

Metabolic changes in deafferented central neurons of an insect, Acheta domesticus. I. Effects upon amino acid uptake and incorporation  

SciTech Connect

Chronic cercal deafferentation of the terminal ganglion in developing crickets (Acheta domesticus), which is known to suppress normal development of giant interneuron dendritic arborizations is shown here to reduce (/sup 3/H)leucine uptake and incorporation into ganglion proteins. Short term deafferentation of adult crickets, in contrast, does not depress amino acid uptake and incorporation significantly. Following unilateral long term deafferentation of the terminal ganglion, a comparison was made of the (/sup 3/H)leucine incorporation into primary dendritic processes and somata of deafferented and normally innervated medial giant interneurons (MGIs) within the same ganglion by means of quantitative autoradiography. Grain densities within dendrites of deafferented MGIs were significantly lower than in paired control MGIs' grain densities within somata of deafferented MGIs also were reduced, although the effects of deafferentation were less pronounced in somata than in target dendrites. These results imply a specific influence of afferent innervation on protein metabolism during growth and development of target postsynaptic elements.

Meyer, M.R.; Edwards, J.S.

1982-11-01

233

AFM characterization of nanobubble formation and slip condition in oxygenated and electrokinetically altered fluids.  

PubMed

Nanobubbles are gas-filled features that spontaneously form at the interface of hydrophobic surfaces and aqueous solutions. In this study, an atomic force microscope (AFM) was used to characterize the morphology of nanobubbles formed on hydrophobic polystyrene (PS) and octadecyltrichlorosilane (OTS) films immersed in DI water, saline, saline with oxygen and an electrokinetically altered saline solution produced with Taylor-Couette-Poiseuille flow under elevated oxygen pressure. AFM force spectroscopy was used to evaluate hydrodynamic and electrostatic forces and boundary slip condition in various fluids. The effect of solution, electric field and surface charge on shape, size and density of nanobubbles as well as slip length was quantified and the results and underlying mechanisms are presented in this paper. PMID:23123096

Bhushan, Bharat; Pan, Yunlu; Daniels, Stephanie

2013-02-15

234

Microemulsion electrokinetic chromatographic determination of bufadienolides in toad venom and in traditional Chinese medicine.  

PubMed

A microemulsion electrokinetic chromatographic (MEEKC) method has been developed and validated for determination of resibufogenin and cinobufagin in toad venom and in traditional Chinese medicine prepared from the venom. The MEEKC method involved use of sodium dodecyl sulfate (SDS) as surfactant, heptane as organic solvent, and butan-1-ol as co-solvent. To improve the separation, the effect of temperature and running buffer pH were evaluated. The optimized conditions (heptane 0.81% (w/w), SDS 3.31% (w/w), butan-1-ol 6.61% (w/w), and 10 mmol L(-1) sodium tetraborate buffer, pH 9.2, and 298 nm as the detection wavelength) enabled useful and repeatable separation of the analytes. PMID:16477424

Xingping, Luo; Zongde, Zhai; Yanfang, Zhao; Liren, Chen; Yongmin, Li

2006-03-01

235

Continuous signal enhancement for sensitive aptamer affinity probe electrophoresis assay using electrokinetic concentration.  

PubMed

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

Cheow, Lih Feng; Han, Jongyoon

2011-09-15

236

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

237

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

238

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

239

Progress report for mutagenic effect of radionuclides incorporated into DNA of Drosophilia melangaster  

SciTech Connect

One objective is to determine the proportion of tritium incorporated into different macromolecules of Drosophila germ cells. The other objective is to determine the nature of mutagenic lesions induced by tritium decay. A specific locus detection system for point mutations that can be analyzed at the molecular level was developed. (ACR)

Lee, W.R.

1981-01-01

240

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

SciTech Connect

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

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

2010-03-01

241

Effective potentials for 1:1 electrolyte solutions incorporating dielectric saturation and repulsive hydration  

E-print Network

and the solvation free energy if the first two or three solvent layers are incorporated explicitly into the model-range corrections were added to the system to account for the water solvent. The first is due to dielectric activity coefficient and is able to capture structural features of contact ion pairs and solvent separated

242

SOIL INCORPORATION OF COVERCROP BIOMASS: EFFECTS ON SOIL MICROORGANISMS AND NITROGEN LEVELS  

Microsoft Academic Search

Summary Biomass production, release of the usable nitrogen ions, ammonium and nitrate, and soil bacterial and fungal populations were measured for four covercrops after harvesting and soil incorporation. Two leguminous crops, Sunn hemp and pigeon pea, were studied as well as sorghum and marigold. As expected, the legumes provided the greatest amounts of soil nitrogen. Sorghum produced by far the

S. Schenck

2003-01-01

243

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

Microsoft Academic Search

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

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

1987-01-01

244

THREE-DIMENSIONAL LONGWAVE INFRARED (LWIR) SYNTHETIC IMAGE GENERATION INCORPORATING ANGULAR EMJSSWITY EFFECTS USING RAY-  

E-print Network

with rotation, translation, and scaling parameters. Each facet is assigned a material index and temperature to geometrically match an actual acquired scene so that radiometric comparisons can be made. INTRODUCTION The last LWIR phenomena using 2-D image templates. It is the goal of this effort to incorporate this radiometric

Salvaggio, Carl

245

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

246

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

247

A glass capillary ultramicroelectrode with an electrokinetic sampling ability.  

PubMed

A glass capillary ultramicroelectrode (tip diameter approximately 1.2 microm) having an electrokinetic sampling ability is described. It is composed of a pulled glass capillary filled with an inner solution and three internal electrodes (Pt working and counter electrodes and an Ag/AgCl reference electrode). The voltammetric response of the capillary electrode is based on electrokinetic transport of analyte ions from the sample solution into the inner solution across the conical tip. It was found that the electrophoretic migration of analytes at the conical tip is faster than electroosmotic flow, enabling electrokinetic transport of analyte ions into the inner solution of the electrode. By using [Fe(CN)6]4- and (ferrocenylmethyl)trimethylammonium (FcTMA+) ions as model analytes, differential pulse voltammetric responses of the capillary electrode were investigated in terms of tip diameter of the capillary, sampling voltage, sampling time, detection limit and selectivity. The magnitude of the response depends on the size and charge of analyte ions. With a capillary electrode having a approximately 1.2-microm tip diameter, which minimizes non-selective diffusional entry of analytes, the response after 1 h sampling at +1.7 V is linearly related to [Fe(CN)6]4- concentration in the range of 0.50-5.0 mM with the detection limit of 30 microM. Application of a potential of the same sign as that of the analyte ion forces the analyte to move out from the electrode to the solution, enabling reuse of the same capillary electrode. The charge-selective detection of analytes with the capillary electrode is demonstrated for [Fe(CN)6]4- in the presence of FcTMA+. PMID:11993675

Hirano, A; Kanai, M; Nara, T; Sugawara, M

2001-01-01

248

Electrokinetic instability near charge-selective hydrophobic surfaces.  

PubMed

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. PMID:25122363

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

2014-07-01

249

Electrokinetic Instability near Charge-Selective Hydrophobic Surfaces  

E-print Network

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 micro- 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; Ganchenko, G S

2014-01-01

250

Effect of fluoride ion incorporation on the structural aspects of barium–sodium borosilicate glasses  

Microsoft Academic Search

Barium–sodium borosilicate glasses containing upto 6wt% fluoride ions were prepared by conventional melt quench method and characterized by 19F, 29Si and 11B nuclear magnetic resonance (NMR) techniques.19F NMR studies have confirmed the presence of mainly linkages like F–Si(n) or F–B(n) along with F–Ba(n). Their relative concentrations are unaffected by F? content in the glass. Incorporation of fluoride ions in the

R. K. Mishra; V. Sudarsan; C. P. Kaushik; Kanwar Raj; R. K. Vatsa; M. Body; A. K. Tyagi

2009-01-01

251

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

NASA Astrophysics Data System (ADS)

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

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

2014-03-01

252

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

253

Effect of polymer nature on the structure and properties of gel composites with incorporated bentonite particles  

Microsoft Academic Search

Composite gels based on polyacrylamide and poly(N-isopropyl acrylamide) with incorporated sodium bentonite particles are synthesized.\\u000a It is shown that the presence of hydrophobic isopropyl groups in a polymer molecule promotes the subsequent formation of highly\\u000a ordered aggregates of clay and cetylpyridinium chloride in a gel composite. An increase in temperature results in the collapse\\u000a of composite gels based on poly(N-isopropyl

E. K. Lavrent’eva; S. G. Starodubtsev; A. R. Khokhlov; V. V. Volkov; K. A. Dembo

2008-01-01

254

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

SciTech Connect

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

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

1987-03-01

255

Dispersion of solute by electrokinetic flow through post arrays and wavy-walled channels.  

PubMed

In this work, we simulate electrokinetically driven transport of unretained solute bands in a variety of two-dimensional spatially periodic geometries (post arrays as well as sinuous/varicose channels), in the thin Debye layer limit. Potential flow fields are calculated using either an inverse method or a Schwarz-Christoffel transform, and transport is modeled using a Monte Carlo method in the transformed plane. In this way, spurious "numerical diffusion" transverse to streamlines is completely eliminated, and streamwise numerical diffusion is reduced to arbitrary precision. Late-time longitudinal dispersion coefficients are calculated for Peclet numbers from 0.1 to 3162. In most geometries, a Taylor-Aris-like scaling law for the dispersion coefficient D(L)/D(L0) = 1 + Pe2/alpha underpredicts dispersion when Pe approximately O(alpha1/2) (here D(L0) is the effective axial diffusion coefficient in the periodic geometry). A two-parameter correlation widely used in the porous media literature, D(L)/D(L0) = 1 + Pe(n)/alpha, agrees slightly better, but much better agreement can be obtained using a new quadratic form: D(L)/D(L0) = 1 + Pe/alpha1 + Pe2/alpha2. A quasi-universal relationship for stream-wise dispersion is offered that predicts 96% of the simulation data to within a factor of 2 in all geometries studied. Comparison with previous work shows that in circular post arrays, the dispersion coefficient for electrokinetic flow is a factor of 3-10 less (depending on Pe and relative post size) than for pressure-driven flow. PMID:15858997

Kirchner, J J; Hasselbrink, E F

2005-02-15

256

Antifungal effectiveness of potassium sorbate incorporated in edible coatings against spoilage molds of apples, cucumbers, and tomatoes during refrigerated storage.  

PubMed

Predominant spoilage molds of fresh apples, cucumbers, and tomatoes stored at 4 °C were isolated and examined for resistance to potassium sorbate (PS) incorporated in polysaccharide edible coatings. The isolated molds were?Penicillium expansum, Cladosporium herbarum, and?Aspergillus niger?from apples.?P. oxalicum?and?C. cucumerinum?were isolated from cucumbers and?P. expansium?and?C. fulvum?from tomatoes. Guar gum edible coating incorporated with PS was the most effective mold inhibitor, significantly (P<0.05) reducing the isolated spoilage molds for 20, 15, and 20 d of storage at 4 °C on apples, cucumbers, and tomatoes, respectively. PS incorporated into pea starch edible coating was less effective and selectively inhibited the isolated mold species, causing significant (P<0.05) reduction in mold on apples, cucumbers, and tomatoes counts for 20, 10 to 15, and 15 to 20 d of storage at 4 °C, respectively. The isolated mold species exhibited different resistances to PS incorporated in the edible coatings. The greatest inhibition (2.9 log CFU/g) was obtained with?C. herbarum?on apples and the smallest (1.1 log CFU/g) was with?P.?oxalicum?on cucumbers and the other isolated mold species exhibited intermediate resistance. The coatings tested, in general, inhibited molds more effectively on apples than on tomatoes and cucumbers. Addition of PS to pea starch and guar gum, edible coatings improved the antifungal activity of PS against isolated spoilage molds on apples, cucumbers, and tomatoes. PS inhibition was most effective against?C. herbarum?on apples and least effective against?P.?oxalicum?on cucumbers. PMID:21535846

Mehyar, Ghadeer F; Al-Qadiri, Hamzah M; Abu-Blan, Hifzi A; Swanson, Barry G

2011-04-01

257

Rapid and label-free separation of Burkitt's lymphoma cells from red blood cells by optically-induced electrokinetics.  

PubMed

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

258

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

259

Effects of arsenic incorporation on jarosite dissolution rates and reaction products  

NASA Astrophysics Data System (ADS)

Batch dissolution experiments were undertaken on synthetic arsenojarosites at pH 2, pH 8, and in ultra-pure water to better understand the influence of As incorporation on the kinetics and reaction products of jarosite dissolution. Incongruent jarosite dissolution was observed in all experiments. Arsenojarosite lacks the pH dependency observed in K-jarosite dissolution, likely the result of surface arsenate-iron complexes preventing protonation at low pH and repelling hydroxyls at high pH. The stronger bonding of arsenate to iron, compared to sulfate to iron, leads to an enrichment of surface layer arsenate-iron complex sites, inhibiting the dissolution of jarosite with time. The secondary reaction products formed during the dissolution of arsenojarosite include maghemite, goethite, and hematite in ultra-pure water, and ferrihydrite in pH 8 Tris buffered solution. Maghemite initially forms and transitions 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. Arsenic also inhibits the formation of goethite and reduces the crystallinity of the observed maghemite reaction products. The coprecipitation of iron oxides with increasing amounts of arsenic results in a change from spherical to "worm-like" aggregate morphology and provides a sink for arsenic released during arsenojarosite dissolution. This study shows that in open systems with a flush of fresh solution, arsenic incorporation in jarosite results in an increase in dissolution rates. In closed systems, however, increasing surface arsenate-iron complexes inhibit further dissolution of the underlying bulk material, causing a reduction in dissolution rates as arsenic incorporation increases.

Kendall, Matthew R.; Madden, Andrew S.; Elwood Madden, Megan E.; Hu, Qinhong

2013-07-01

260

Mitigation of methane emissions from rice fields: Possible adverse effects of incorporated rice straw  

NASA Astrophysics Data System (ADS)

Increased world demand for rice production may lead to an increase in methane emission to the atmosphere and future global warming. One suggested way to reduce methane emission is to discourage the practice of incorporating previous crop residue prior to planting rice, since the residue may enhance methane emission from flooded rice fields. This concept is supported by data from a 2-year study of flooded rice fields on two different soil types in Texas. In 1990, rice stubble from 1989 was incorporated into both soils. Seasonal methane emission from a Lake Charles clay field increased from 15.9 g m-2 in 1989 to 31.0 g m-2 in 1990. In the Beaumont clay field, seasonal methane emission increased from 4.5 to 11.4 g m-2. While methane emission increased between 1989 and 1990, grain yield dropped by 2100 and 840 kg ha-1 in the Lake Charles and Beaumont fields, respectively. Visual inspection at harvest indicated that the 1990 rice yield decrease resulted from grain abortion, presumably caused by the rice cultivar's sensitivity to soil anaerobiosis. The calculated amount of organic carbon not translocated to grain was comparable to the estimated amount of organic carbon required for the increased methane emission. We hypothesize that labile carbon in straighthead susceptible rice cultivars can "leak" from roots damaged by excessively anaerobic soil and be metabolized to its equivalent in methane. These data suggest that minimizing incorporation of crop residue prior to planting can decrease methane emission from flooded rice and reduce the potential for yield loss, particularly with some cultivars and in soils with low rates of seepage and percolation.

Sass, R. L.; Fisher, F. M.; Harcombe, P. A.; Turner, F. T.

1991-09-01

261

Incorporation of solvent effects into ab initio molecular orbital calculations by the generalized Born formula. Formulation, parameterization, and applications  

Microsoft Academic Search

A recently developed method for incorporation of solvent effects into ab initio SCF calculations using the generalized Born formula was modified by 1.(i) introducing a steric factor which accounts for the exclusion of the solvent shell of an atom in a molecule by the other atoms, and2.(ii) re-determination of the parameters used to evaluate the atomic radii which are expressed

Ohgi Takahashi; Hiroyuki Sawahata; Yasushi Ogawa; Osamu Kikuchi

1997-01-01

262

Effect of nitrogen incorporation to electrical and optical properties of amorphous carbon thin film prepared by thermal CVD  

Microsoft Academic Search

Nitrogen-doped amorphous carbon thin films have been prepared by thermal chemical vapor deposition (CVD) technique at different temperature. The preparation involved argon, camphor and nitrogen as carrier gas, carbon source and dopant respectively. The effects of nitrogen incorporation in the amorphous carbon thin film on electrical and optical properties was characterized by using Advantest R6243 DC Voltage Current Source\\/Monitor and

F. Mohamad; A. Yusof; U. M. Noor; M. Rusop

2011-01-01

263

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

264

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 1.0Vcm(-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 9mgL(-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 1.4mgO2L(-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

265

Electrokinetic remediation of soils contaminated with electroplating wastes  

SciTech Connect

Electrokinetic remediation of soils simulated with electroplating waste contamination was investigated in two soils, kaolin and glacial till. Soil samples were contaminated with nickel, cadmium and hexavalent chromium and subjected to an external electric field for four days. Results of these experiments revealed that the soil composition plays an important role in electrokinetic remediation. Due to induced electric potential, a distinct pH gradient was developed in kaolin; however, in glacial till alkaline conditions existed throughout the soil because of its high carbonate buffering capacity. The movement of cationic metallic contaminants, Ni(II) and Cd(II), from the anode to the cathode was significant in kaolin as compared to glacial till. Because of high pH conditions near the cathode, Ni(II) and Cd(II) were precipitated in kaolin. In glacial till, however, because of alkaline conditions throughout the soil, most of Ni(II) and Cd(II) precipitated without migration. Overall, this study demonstrates that anion exchange, cation exchange and precipitation were the significant fixation mechanisms of nickel, cadmium and chromium in soils.

Reddy, K.R.; Parupudi, U.S. [Univ. of Illinois, Chicago, IL (United States). Dept. of Civil and Materials Engineering; Devulapalli, S. [Patterson Associates Inc., Chicago, IL (United States)

1996-10-01

266

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

267

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

268

Effects of titanium surface anodization with CaP incorporation on human osteoblastic response.  

PubMed

In this study we investigated whether anodization with calcium phosphate (CaP) incorporation (Vulcano®) enhances growth factors' secretion, osteoblast-specific gene expression, and cell viability, when compared to acid etched surfaces (Porous®) and machined surfaces (Screw®) after 3 and 7days. Results showed significant cell viability for Porous and Vulcano at day 7, when compared with Screw (p=0.005). At the same time point, significant differences regarding runt-related transcription factor 2 (Runx2), alkaline phosphatase (ALP) and bone sialoprotein (BSP) expression were found for all surfaces (p<0.05), but with greater fold induction for Porous and Vulcano. The secretion of transforming growth factor ?1 (TGF-?1) and bone morphogenetic protein 2 (BMP-2) was not significantly affected by surface treatment in any experimental time (p>0.05). Although no significant correlation was found for growth factors' secretion and Runx2 expression, a significant positive correlation between this gene and ALP/BSP expression showed that their strong association is independent on the type of surface. The incorporation of CaP affected the biological parameters evaluated similar to surfaces just acid etched. The results presented here support the observations that roughness also may play an important role in determining cell response. PMID:23498218

Oliveira, Natássia Cristina Martins; Moura, Camilla Christian Gomes; Zanetta-Barbosa, Darceny; Mendonça, Daniela Baccelli Silveira; Cooper, Lyndon; Mendonça, Gustavo; Dechichi, Paula

2013-05-01

269

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

270

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.

271

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

272

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

273

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 ...

274

Effects of nucleoside analog incorporation on DNA binding to the DNA binding domain of the GATA-1 erythroid transcription factor.  

PubMed

We investigate here the effects of the incorporation of the nucleoside analogs araC (1-beta-D-arabinofuranosylcytosine) and ganciclovir (9-[(1,3-dihydroxy-2-propoxy)methyl] guanine) into the DNA binding recognition sequence for the GATA-1 erythroid transcription factor. A 10-fold decrease in binding affinity was observed for the ganciclovir-substituted DNA complex in comparison to an unmodified DNA of the same sequence composition. AraC substitution did not result in any changes in binding affinity. 1H-15N HSQC and NOESY NMR experiments revealed a number of chemical shift changes in both DNA and protein in the ganciclovir-modified DNA-protein complex when compared to the unmodified DNA-protein complex. These changes in chemical shift and binding affinity suggest a change in the binding mode of the complex when ganciclovir is incorporated into the GATA DNA binding site. PMID:10037146

Foti, M; Omichinski, J G; Stahl, S; Maloney, D; West, J; Schweitzer, B I

1999-02-01

275

Effect of hydrogen on the indium incorporation in InGaN epitaxial films  

NASA Astrophysics Data System (ADS)

The InN percent in metalorganic chemical vapor deposition (MOCVD) and atomic layer epitaxy (ALE) grown InGaN was found to be significantly influenced by the amount of hydrogen flowing into the reactor. The temperature ranges for this study are 710-780 °C for MOCVD, and 650-700 °C for ALE. For a given set of growth conditions, an increase of up to 25% InN in InGaN, as determined by x-ray diffraction, can be achieved by reducing the hydrogen flow from 100 to 0 sccm. Additionally, the hydrogen produced from the decomposition of ammonia does not seem to change the InN percent in the films, indicating that the ammonia decomposition rate is less than 0.1%. The phenomenon of having hydrogen control the indium incorporation was not reported in the growth of any other III-V compound previously studied.

Piner, E. L.; Behbehani, M. K.; El-Masry, N. A.; McIntosh, F. G.; Roberts, J. C.; Boutros, K. S.; Bedair, S. M.

1997-01-01

276

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

277

Remediating ethylbenzene-contaminated clayey soil by a surfactant-aided electrokinetic (SAEK) process  

Microsoft Academic Search

The objectives of this research are to investigate the remediation efficiency and electrokinetic behavior of ethylbenzene-contaminated clay by a surfactant-aided electrokinetic (SAEK) process under a potential gradient of 2 Vcm?1. Experimental results indicated that the type of processing fluids played a key role in determining the removal performance of ethylbenzene from clay in the SAEK process. A mixed surfactant system

Ching Yuan; Chih-Huang Weng

2004-01-01

278

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

279

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

280

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

281

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

PubMed

A specific, accurate, precise and reproducible micellar electrokinetic chromatographic method was developed for in vitro and in vivo estimation of rosuvastatin, a synthetic and potent HMG-CoA inhibitor, in rabbit plasma. Further, its pharmacokinetics in the presence of niacin, which could be co-administered for monitoring of severe hypercholestremia, was investigated. The assay procedures involved simple liquid-liquid extraction of rosuvastatin and internal standard, atorvastatin, from a small plasma volume directly into acetonitrile. The organic layer was separated and evaporated under a gentle stream of nitrogen. The residue was reconstituted in the mobile phase and injected electrokinetically into electropherosis system. The background electrolyte consisted of borate buffer (25.0?mm, pH?9.5), 10.0% organic modifier (5.0% methanol?+?5.0% acetonitrile) and 25.0?mm sodium dodecyl sulfate at 20.0?kV applied voltage and 215.0?nm detection wavelength for the effective separation of rosuvastatin, niacin and atorvastatin. Copyright © 2014 John Wiley & Sons, Ltd. PMID:24828212

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

2014-12-01

282

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

283

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

2014-09-15

284

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.

Malgaretti, Paolo; Rubi, J Miguel

2014-01-01

285

Cyclodextrin-mediated enantioseparation in microemulsion electrokinetic chromatography.  

PubMed

Chiral separation by means of cyclodextrins has a long-standing tradition in capillary electrophoresis techniques. Here we present a chiral method utilizing the recently introduced microemulsion electrokinetic chromatography. The microemulsion consisting of 1.0% SDS, 4.0% 1-butanol, 3.0% 2-propanol, 0.5% ethylacetate, and 91.5% 20 mM phosphate buffer pH 2.5 serves as a pseudostationary phase which is complemented by sulfated cyclodextrin as a second phase. The analytes partition between the aqueous running buffer and both pseudostationary phases, the oil droplets and the cyclodextrins. Enantiomers are separated due to the formation of transient diastereomeric complexes with the cyclodextrins. For the racemates of ephedrine derivatives studied here sulfated ?-cyclodextrin was successfully applied. The method is appropriate to resolve an entire series of chiral phenethylamines and can be used for separation of the racemates and impurity profiling, e.g., the determination of the enantiomeric excess. PMID:23283790

Borst, Claudia; Holzgrabe, Ulrike

2013-01-01

286

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

287

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

288

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

289

Effects of incorporation of fluorocarbon and hydrocarbon surfactants into perfluorosulfonic acid (Nafion) membranes  

SciTech Connect

Perfluorinated ionomer membranes such as Nafion have numerous uses in both industrial chemical practice and in chemical research. Applications include the chloralkali process, H[sub 2]/O[sub 2] fuel cells, biomedical sensing, and other types of chemical sensors based on modified electrodes. Significant permeability improvements can be made to perfluorinated ionomer films by incorporating sulfonated surfactants of suitable size into the membrane microstructure. A variety of 20-[mu]m composite Nafion/surfactant membranes were prepared from DMF casting solutions containing Nafion and the sodium salts of perfluoro-1-butanesulfonic acid (perf-ButSO[sub 3]Na), perfluoro-1-octanesulfonic acid (perf-OctSO[sub 3]Na) and 1-octanesulfonic acid (OctSO[sub 3]Na). The time required for 50% extraction of the surfactants from the membranes into water was 1 min for OctSO[sub 3]Na, 5 min for perf-ButSO[sub 3]Na, and approximately 3 days for perf-OctSO[sub 3]Na. Extraction of perf-OctSO[sub 3]Na into isooctane contacting solutions was not observable over periods of days. For membranes containing surfactants and exchanged with silver(I) ion, 3-fold permeability improvements can be obtained for the separation of 1,5-hexadiene from 1-hexene and n-hexane without any decreases in separation factors. Observed flux improvements are larger than the increase in ion-exchange site density and are attributed to increased mobility of olefins between carrier sites due to the presence of specific surfactants. Results indicate that movement of olefins in Nafion occurs primarily through an interfacial region of the film structure. The ability of a surfactant to improve transport performance is dependent on its ability to partition into the interfacial region. 27 refs., 3 figs., 2 tabs.

Rabago, R.; Noble, R.D.; Koval, C.A. (Univ. of Colorado, Boulder, CO (United States))

1994-07-01

290

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

291

THE LOCAL EFFECT TIME (LET) AND HOW IT INCORPORATES ECOLOGY INTO RESIDENCE TIME  

EPA Science Inventory

A clear and direct connection between constituent/water residence times and ecological effects is necessary to quantitatively relate these time scales to ecology. The concept of "local effect time" (LET) is proposed here as a time scale with adequate spatial resolution to relate ...

292

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

293

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 ...

294

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

295

Effect of ciprofloxacin incorporation in PVA and PVA bioactive glass composite scaffolds  

E-print Network

agents for a prolonged time at the infection site and with low level of side effects may improve osteomyelitis treatment protocol combines both surgical removing of dead bone tissue and prolonged parenteral

Paris-Sud XI, Université de

296

An Investigation into a Methodology to Incorporate Skill Level Effects into the Logistics Composite Model.  

National Technical Information Service (NTIS)

The Logistics Composite Model (LCOM), a major part of the USAF maintenance manpower determination process, should be capable of providing information on the relationship between the workcenter's performance and skill level effects. This thesis investigate...

R. Garcia, J. P. Racher

1981-01-01

297

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

Microsoft Academic Search

Hydrologic and ecologic studies in mountainous terrain are sensitive to the temporal and spatial distri- bution of precipitation. In this study a geostatistical model, Auto-Searched Orographic and Atmospheric Effects Detrended Kriging (ASOADeK), is introduced to map mountain precipitation using only precipi- tation gauge data. The ASOADeK model considers both precipitation spatial covariance and orographic and atmospheric effects in estimating precipitation

Huade Guan; John L. Wilson; Oleg Makhnin

2005-01-01

298

Effect of substituents on the thermochromism of stilbazolium merocyanines incorporated in epoxy resin  

NASA Astrophysics Data System (ADS)

The thermochromic effect (in the range 283-333 K) on the spectroscopic properties of stilbazolium merocyanine derivatives are substituted by groups of different donor-acceptor qualities (-H, -C(CH3)3, -NO2 and -OCH3) located in the ortho position to the carbonyl group of the quinonoid ring was examined. The samples were embedded in a polymer matrix from the epoxy resin. Results show that the size of thermochromic effect of stilbazolium merocyanines can be influenced by attaching substituents of different donor-acceptor nature. The smallest value of this effect was recorded for dye substituted by large tert-butyl groups, and the largest for derivative with -NO2 group substituent. The thermosensitvity investigated dyes was dependent on: (1) an equilibrium between quinonoid form and benzenoid form (zwitterion), (2) the polarization of molecules that facilitate the formation of H-type aggregates.

Cegielski, Roman; Niedbalska, Ma?gorzata

2013-02-01

299

An improved jet noise scaling law which incorporates phase differences due to flight effects  

NASA Astrophysics Data System (ADS)

The influence of flight velocity on the noise generation of a single stream shock free circular jet is studied. A previous scaling law is modified to improve the scaling of acoustical interference effects. In addition, it is shown that the Lighthill approach does consider the refraction processes known to occur in high speed jets.

Michel, U.

1983-04-01

300

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

301

Creating a Ripple Effect: Incorporating Multimedia-Assisted Project-Based Learning in Teacher Education  

ERIC Educational Resources Information Center

This article explores the effects of multimedia-assisted, project-based learning in teacher education. We conducted pre- and post-surveys to investigate how the experience of developing multimedia projects influenced preservice teachers' knowledge and self-efficacy in (a) technology, (b) subject matter, and (c) teaching. Forty-two preservice…

Seo, Kay Kyeongju; Templeton, Rosalyn; Pellegrino, Debra

2008-01-01

302

Effect of Control-released Basic Fibroblast Growth Factor Incorporated in ?-Tricalcium Phosphate for Murine Cranial Model  

PubMed Central

Background: ?-Tricalcium phosphate (?-TCP) is used clinically as a bone substitute, but complete osteoinduction is slow. Basic fibroblast growth factor (bFGF) is important in bone regeneration, but the biological effects are very limited because of the short half-life of the free form. Incorporation in gelatin allows slow release of growth factors during degradation. The present study evaluated whether control-released bFGF incorporated in ?-TCP can promote bone regeneration in a murine cranial defect model. Methods: Bilateral cranial defects of 4?mm in diameter were made in 10-week-old male Sprague-Dawley rats treated as follows: group 1, 20 ?l saline as control; group 2, ?-TCP disk in 20 ?l saline; group 3, ?-TCP disk in 50 ?g bFGF solution; and group 4, ?-TCP disk in 50 ?g bFGF-containing gelatin hydrogel (n = 6 each). Histological and imaging analyses were performed at 1, 2, and 4 weeks after surgery. Results: The computed tomography value was lower in groups 3 and 4, whereas the rate of osteogenesis was higher histologically in group 4 than in the other groups. The appearance of tartrate-resistant acid phosphate–positive cells and osteocalcin-positive cells and disappearance of osteopontin-positive cells occurred earlier in group 4 than in the other groups. Conclusions: These findings suggest that control-released bFGF incorporated in ?-TCP can accelerate bone regeneration in the murine cranial defect model and may be promising for the clinical treatment of cranial defects. PMID:25289319

Shimizu, Azusa; Tajima, Satoshi; Tobita, Morikuni; Tanaka, Rica; Tabata, Yasuhiko

2014-01-01

303

Effects of cytotoxic agents on TdR incorporation and growth delay in human colonic tumour xenografts.  

PubMed Central

The relationship between the utilization of 3H-thymidine in situ ([3H]-TdR fractional incorporation or TFI) and tumour growth delay after treatment with various cytotoxic agents has been examined. It is shown that (a) it is not possible to predict tumour growth delay, or to select the most effective agent, from changes in TFI 1 day after treatment; (b) there is a good correlation between tumour growth delay and the time for recovery of TFI to the pretreatment level; (c) there is a relationship within a tumour line between the depression of TFI 4 days after treatment and growth dealy induced by the same treatment. This relationship appears to be independent of the mechanism by which the agent exerts its cytotoxic effect. PMID:911658

Houghton, P. J.; Houghton, J. A.; Taylor, D. M.

1977-01-01

304

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

305

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

306

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

Microsoft Academic Search

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

Hanna Salminen; Marina Heinonen; Eric A. Decker

2010-01-01

307

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

308

DNET: a model for incorporating feedback effects in salt dissolution processes  

SciTech Connect

For nuclear waste isolation in deep, geologic formations, transport in groundwater appears to be one of the more likely means for radioactive waste to migrate from the depository to the biosphere. With respect to a depository in bedded salt, transport in groundwater would, for most breachment scenarios, have to be preceded by dissolution of all or portions of the salt layers surrounding the depository. The Dynamic Network (DNET) model provides a capability for investigating the rate of salt dissolution associated with a variety of disruptive events and processes and also provides a capability for investigating the effects of feedback mechanisms such as thermal expansion, subsidence, fracture formation and salt creep.

Cranwell, R.M.; Campbell, J.E.

1981-01-01

309

The surface cracking behavior in air plasma sprayed thermal barrier coating system incorporating interface roughness effect  

NASA Astrophysics Data System (ADS)

The objective of this work is to understand the effect of interface roughness on the strain energy release rate and surface cracking behavior in air plasma sprayed thermal barrier coating system. This is achieved by a parameter investigation of the interfacial shapes, in which the extended finite element method (XFEM) and periodic boundary condition are used. Predictions for the stress field and driving force of multiple surface cracks in the film/substrate system are presented. It is seen that the interface roughness has significant effects on the strain energy release rate, the interfacial stress distribution, and the crack propagation patterns. One can see the completely different distributions of stress and strain energy release rate in the regions of convex and concave asperities of the substrate. Variation of the interface asperity is responsible for the oscillatory characteristics of strain energy release rate, which can cause the local arrest of surface cracks. It is concluded that artificially created rough interface can enhance the durability of film/substrate system with multiple cracks.

Zhang, W. X.; Fan, X. L.; Wang, T. J.

2011-11-01

310

Effect of excipients on PLGA film degradation and the stability of an incorporated peptide.  

PubMed

The effect of pH modifying excipients on the chemical stability of a model peptide (VYPNGA) and the degradation of poly(dl-lactide-co-glycolide)(PLGA) was studied in PLGA films under accelerated storage conditions. pH modifiers included a basic amine (proton sponge), a basic salt (magnesium hydroxide) and two pH buffers (ammonium acetate and magnesium acetate). Changes in film pH were monitored using (13)C NMR, peptide degradation products were quantified by LC/MS/MS and PLGA degradation was analyzed by TGA, DSC and SEC. Inclusion of pH modifiers had little impact on PLGA degradation. The proton sponge affected an initial decrease in pH but reduced peptide deamidation and chain cleavage relative to an unbuffered control. Magnesium hydroxide produced an initial increase in pH but also showed increased peptide deamidation. Ammonium acetate decreased pH and increased peptide chain cleavage, presumably due to increased PLGA hydrolysis. Magnesium acetate buffer increased the initial pH but resulted in increased peptide loss. The extent of peptide acylation increased in all formulations, most notably in the proton sponge modified films. The effectiveness of pH modifiers in PLGA formulations under storage conditions is dependant on both the mechanism of pH alteration and the peptide degradation reaction of interest. PMID:17207882

Houchin, M L; Neuenswander, S A; Topp, E M

2007-02-26

311

Effect of Excipients on PLGA Film Degradation and the Stability of an Incorporated Peptide  

PubMed Central

The effect of pH modifying excipients on the chemical stability of a model peptide (VYPNGA) and the degradation of poly(DL-lactide-co-glycolide)(PLGA) was studied in PLGA films under accelerated storage conditions. pH modifiers included a basic amine (proton sponge), a basic salt (magnesium hydroxide) and two pH buffers (ammonium acetate and magnesium acetate). Changes in film pH were monitored using 13C NMR, peptide degradation products were quantified by LC/MS/MS and PLGA degradation was analyzed by TGA, DSC and SEC. Inclusion of pH modifiers had little impact on PLGA degradation. The proton sponge affected an initial decrease in pH but reduced peptide deamidation and chain cleavage relative to an unbuffered control. Magnesium hydroxide produced an initial increase in pH but also showed increased peptide deamidation. Ammonium acetate decreased pH and increased peptide chain cleavage, presumably due to increased PLGA hydrolysis. Magnesium acetate buffer increased the initial pH but resulted in increased peptide loss. The extent of peptide acylation increased in all formulations, most notably in the proton sponge modified films. The effectiveness of pH modifiers in PLGA formulations under storage conditions is dependant on both the mechanism of pH alteration and the peptide degradation reaction of interest. PMID:17207882

Houchin, M.L.; Neuenswander, S.A.; Topp, E.M.

2007-01-01

312

Simultaneous removal of organic compounds and heavy metals from soils by electrokinetic remediation with a modified cyclodextrin  

Microsoft Academic Search

Thousands of sites are contaminated with both heavy metals and organic compounds and these sites pose a major threat to public health and the environment. Previous studies have shown that electrokinetic remediation has potential to remove heavy metals and organic compounds when they exist individually in low permeability soils. This paper presents the feasibility of using cyclodextrins in electrokinetic remediation

Kranti Maturi; Krishna R. Reddy

2006-01-01

313

Incorporation of adhesive liners in amalgam: effect on compressive strength and creep.  

PubMed

This study evaluated the effects of two adhesive resin liners (Panavia EX and Amalgambond) on the compressive strength and creep rate of a single composition high-copper amalgam alloy (Tytin). Cylindrical specimens were prepared by dead-loading or hand-condensing amalgam in a Teflon mold which was unlined, lined with Panavia EX, or lined with Amalgambond. Compressive strength specimens were tested at 1 hour, 24 hours, and 7 days after preparation. Creep specimens were tested at 7 days. The adhesive resin liners did not significantly affect the strength of the Tytin specimens prepared by dead-loading (P greater than 0.05). The Panavia EX significantly reduced the strength of the Tytin specimens prepared by hand-condensing (P less than 0.05). The creep rate was not significantly affected by either resin liner. PMID:1930843

Charlton, D G; Murchison, D F; Moore, B K

1991-08-01

314

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

315

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.

316

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

317

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

318

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

PubMed

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

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

2014-06-01

319

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

320

Inhibitory effects on selected oral bacteria of antibacterial agents incorporated in a glass ionomer cement.  

PubMed

The objectives of the study were to investigate the antimicrobial efficacy, over time, of combining antibacterial agents with a glass ionomer cement (GIC). This was assessed using an agar diffusion test. Chlorhexidine hydrochloride, cetylpyridinium chloride, cetrimide and benzalkonium chloride were added to Fuji IX GIC at 0, 1, 2 and 4% w/w. Antibacterial-GIC specimens were placed onto agar plates inoculated with one of six bacterial species (Streptococcis, Lactobacillus, and Actinomyces, two each) and the area of inhibition calculated after 24 h incubation. The experiment was repeated weekly and at week 11 the surface of the specimen was abraded prior to replacing on inoculated agar plates. Control specimens of the GIC produced no bacterial inhibition. The antibacterial-GIC combination specimens showed significant inhibition which decreased at different rates over the test period. Resurfacing of the specimens showed a dramatic increase of antibacterial action similar to levels produced on week 1. CT-GIC showed the greatest (p < 0.005) inhibitory effect throughout the experimental period for 4 out of 6 test bacteria. The addition of antibacterial agents to Fuji IX creates a GIC material with significant antimicrobial action in vitro which is dependent on concentration and type of antibacterial agent, and appears to be associated primarily with a release of the antibacterial from the surface layer of the specimen. PMID:12652048

Botelho, Michael G

2003-01-01

321

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

322

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

323

Effect of glass fiber incorporation on flexural properties of experimental composites.  

PubMed

This study evaluated the effect of fiber addiction in flexural properties of 30?wt% silica filled BisGMA resin (FR) or unfilled Bis-GMA (UR). Ten groups were created (N = 10) varying the resin (FR or UR) and quantity of glass fibers (wt%: 0, 10, 15, 20, and 30). Samples (10?×?2?×?1?mm) were submitted to flexural strength test following SEM examination. Data were analyzed by two-way ANOVA, Tukey, and Student t-test (? = 0.05). Results for flexural strength (MPa) were FR-groups: 0% (442.7 ± 140.6)(C), 10% (772.8 ± 446.3)(ABC), 15% (854.7 ± 297.3)(AB), 20% (863.4 ± 418.0)(A), 30% (459.5 ± 140.5)(BC); UR-groups: 0% (187.7 ± 120.3)(B), 10% (795.4 ± 688.1)(B), 15% (1999.9 ± 1258.6)(A), 20% (1911.5 ± 596.8)(A), and 30% (2090.6 ± 656.7)(A), and for flexural modulus (GPa) FR-groups: 0% (2065.63 ± 882.15)(B), 10% (4479.06 ± 3019.82)(AB), 15% (5694.89 ± 2790.3)(A), 20% (6042.11 ± 3392.13)(A), and 30% (2495.67 ± 1345.86)(B); UR-groups: 0% (1090.08 ± 708.81)(C), 10% (7032.13 ± 7864.53)(BC), 15% (19331.57 ± 16759.12)(AB), 20% (15726.03 ± 8035.09)(AB), and 30% (29364.37 ± 13928.96)(A). Fiber addiction in BisGMA resin increases flexural properties, and the interaction between resin and fibers seems better in the absence of inorganic fillers increasing flexural properties. PMID:25136595

Fonseca, Rodrigo Borges; Marques, Aline Silva; Bernades, Karina de Oliveira; Carlo, Hugo Lemes; Naves, Lucas Zago

2014-01-01

324

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

PubMed Central

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

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

2014-01-01

325

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

NASA Astrophysics Data System (ADS)

GaAs-based quaternary ferromagnetic semiconductor (Ga, Mn)(As, Sb) has been successfully prepared by molecular-beam epitaxy. High-resolution x-ray diffraction measurements indicate that the lattice constant has a notable alteration with changing Sb content. Magnetic measurements demonstrate the same evolution of the Curie temperature TC and the effective Mn content xeff with increasing Sb content. The incorporation of low Sb content is of benefit to increasing xeff, thus, increasing TC. However, higher Sb content degrades the crystal quality, resulting in a decrease of xeff. Experimental results show that TC is proportional to the product of xeff and p1/3, which is consistent with the Zener Model. The exchange energy N0? is calculated to be -1.09 eV, which is similar to that of (Ga, Mn)As.

Deng, J. J.; Che, J. T.; Chen, J.; Wang, W. J.; Hu, B.; Wang, H. L.; Zhao, J. H.

2013-12-01

326

Effectiveness of strategies incorporating training and support of traditional birth attendants on perinatal and maternal mortality: meta-analysis  

PubMed Central

Objective To assess the effectiveness of strategies incorporating training and support of traditional birth attendants on the outcomes of perinatal, neonatal, and maternal death in developing countries. Design Systematic review with meta-analysis. Data sources Medline, Embase, the Allied and Complementary Medicine database, British Nursing Index, Cochrane Library, Cumulative Index to Nursing and Allied Health Literature, BioMed Central, PsycINFO, Latin American and Caribbean Health Sciences Literature database, African Index Medicus, Web of Science, Reproductive Health Library, and Science Citation Index (from inception to April 2011), without language restrictions. Search terms were “birth attend*”, “traditional midwife”, “lay birth attendant”, “dais”, and “comadronas”. Review methods We selected randomised and non-randomised controlled studies with outcomes of perinatal, neonatal, and maternal mortality. Two independent reviewers undertook data extraction. We pooled relative risks separately for the randomised and non-randomised controlled studies, using a random effects model. Results We identified six cluster randomised controlled trials (n=138?549) and seven non-randomised controlled studies (n=72?225) that investigated strategies incorporating training and support of traditional birth attendants. All six randomised controlled trials found a reduction in adverse perinatal outcomes; our meta-analysis showed significant reductions in perinatal death (relative risk 0.76, 95% confidence interval 0.64 to 0.88, P<0.001; number needed to treat 35, 24 to 70) and neonatal death (0.79, 0.69 to 0.88, P<0.001; 98, 66 to 170). Meta-analysis of the non-randomised studies also showed a significant reduction in perinatal mortality (0.70, 0.57 to 0.84, p<0.001; 48, 32 to 96) and neonatal mortality (0.61, 0.48 to 0.75, P<0.001; 96, 65 to 168). Six studies reported on maternal mortality and our meta-analysis showed a non-significant reduction (three randomised trials, relative risk 0.79, 0.53 to 1.05, P=0.12; three non-randomised studies, 0.80, 0.44 to 1.15, P=0.26). Conclusion Perinatal and neonatal deaths are significantly reduced with strategies incorporating training and support of traditional birth attendants. PMID:22134967

2011-01-01

327

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

328

Experimental test of new theoretical models for the electrokinetic properties of biological membranes. The effect of UO/sup 2 + +/ and tetracaine on the electrophoretic mobility of bilayer membranes and human erythrocytes  

SciTech Connect

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 UO/sup 2 + +/ on the electrophoretic mobility of model membranes and human erythrocytes in 0.15 M NaCl at pH 5. We used UO/sup 2 + +/ 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, UO/sup 2 + +/ adsorbs strongly to egg phosphatidylcholine (PC) vesicles: 0.1 mM UO/sup 2 + +/ 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 UO/sup 2 + +/ changes the zeta potential of PC/PS vesicles (10 mol % PS) from -13 to +37 mV. In contrast, UO/sup 2 + +/ 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 UO/sup 2 + +/ 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.

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

1986-12-01

329

A two-scale non-local model of swelling porous media incorporating ion size correlation effects  

NASA Astrophysics Data System (ADS)

A new two-scale model is proposed for derivation of the macroscopic modified effective stress principle for swelling porous media saturated by an electrolyte solution containing finite size ions. A non-local pore-scale model is developed within the framework of Statistical Mechanics in conjunction with the thermodynamic approach based on Density Functional Theory leading to a nonlinear integral Fredholm equation of second kind for the ion/nanopore correlation function coupled with Poisson problem for the electric double layer potential. When combined with the fluid equilibrium condition such non-local electrochemical problem gives rise to a constitutive law for the fluid stress tensor in terms of the disjoining pressure which is decomposed into several components of different nature. The homogenization procedure based on formal asymptotic expansions is applied to up-scale the model to the macroscale leading to a two-scale constitutive law for the swelling pressure appearing in the modified effective stress principle with improved accuracy incorporating the deviations from the Gouy-Chapman Poisson-Boltzmann-based theory due to the finite size short-range ion-ion correlation effects. The integro-differential problem posed in a periodic cell is discretized by collocation schemes. Numerical results are obtained for a stratified arrangement of parallel macromolecules showing that the effects of ion-ion correlation forces give rise to anomalous attraction patterns between the particles for divalent ions.

Le, T. D.; Moyne, C.; Murad, M. A.; Lima, S. A.

2013-12-01

330

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

331

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

332

Enhanced electrokinetic treatment of different marine sediments contaminated by heavy metals.  

PubMed

In the present work, the application of an assisted electrokinetic process for the removal of heavy metals from real contaminated sediments was investigated. The process made use of both chemical and physical methods, including addition of chelating and acid agents, as well as application of a hydraulic gradient. Lab-scale electrokinetic runs were applied on two different dredged sediments varying the applied voltage gradient and the treatment duration. The use of EDTA significantly improved the overall performance of the electrokinetic treatment for sediment V (more than 60% mobilized for each metal), while only aggressive acid conditioning with nitric acid was able to remove significant amounts of heavy metals (up to 40.5% for Pb) from sediment S due to the strong buffering capacity of this material. This clearly assesses that the specific characteristics of the materials under concern and the reactions occurring at the electrodes must be carefully evaluated when applying an electroremediation process. PMID:18569295

De Gioannis, Giorgia; Muntoni, Aldo; Polettini, Alessandra; Pomi, Raffaella

2008-07-01

333

Separation and determination of nitrofuran antibiotics in turbot fish by microemulsion electrokinetic chromatography.  

PubMed

A microemulsion electrokinetic chromatography (MEEKC) method has been developed for the determination of four nitrofuran antibiotics (furazolidone (FZD), furaltadone (FTD), nitrofurazone (NFZ) and nitrofurantoin (NFT)) in turbot fish. The effect of buffer the pH, the concentration of SDS and the concentrations of octane and butan-1-ol were studied systematically. With the optimized experimental conditions (octane, 0.82% (w/w); SDS, 3.48% (w/w); butan-1-ol, 6.48% (w/w); and 10 mM sodium tetraborate buffer (pH 9.70), with 30 kV as the applied voltage) all four analytes were baseline-separated within 8 min. Regression equations revealed a good linear relationship between the peak area of each compound and its concentration. The correlation coefficients of the four analytes were from 0.9945 to 0.9999. The relative standard deviations of the migration times and the peak areas were <1.84 and 5.16% (intra-day). The obtained recovery ranged between 97 and 104%. Moreover, the method was successfully validated and applied to the determination of nitrofuran antibiotics in contaminated fish. PMID:19609023

Jiang, Ting-Fu; Lv, Zhi-Hua; Wang, Yuan-Hong; Yue, Mei-E; Lian, Shuai

2009-07-01

334

[Determination of five coumarins in radix glehniae by micellar electrokinetic capillary chromatography].  

PubMed

A micellar electrokinetic capillary chromatography method with ultraviolet detection was developed for the simultaneous determination of psoralen, xanthotoxin, isoimpinellin, bergapten and scopoletin in Radix Glehniae. The separation was performed on an uncoated fused silica capillary column (50.2 cm x 75 microm x 40 cm) with 20 mmol x L(-1) borax solution (pH 9.6) containing 16 mmol x L(-1) sodium dodecylsulfate (SDS) and 15% acetonitrile as running buffer at applied voltage of 22 kV. The detection wavelength was 214 nm. The effects of concentrations of borax solution, sodium dodecylsulfate (SDS), and organic modifier, voltage, temperature on the separation and sensitivity were investigated. The five active constituents were completely separated within 7 min. The linear ranges of psoralen, xanthotoxin, isoimpinellin, bergapten and scopoletin were 9.91-82.6, 37.2-162, 2.23-18.6, 2.73-22.3 and 2.89-20.1 mg x L(-1), respectively. And the average recoveries were 98.9%, 98.4%, 101.3%, 99.1% and 98.0%, respectively. This simple and rapid method provided a new basis for assessment on quality of Radix Glehniae. PMID:20939281

Liu, Man; Kong, Dezhi; Yang, Wei; Wang, Qiao; Zhang, Lantong

2010-07-01

335

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

336

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

337

Structure selective complexation of cyclodextrins with five polyphenols investigated by capillary electrokinetic chromatography.  

PubMed

The complexation of five polyphenols, namely trans-resveratrol, astilbin, taxifolin, ferulic acid, and syringic acid (guest molecules) with ?-, ?-, and ?-cyclodextrin (host molecules), was investigated by capillary electrokinetic chromatography. The binding constants were calculated based on the effective electrophoretic mobility change of guests with the addition of cyclodextrins into the background electrolyte. Because of cavity size, cyclodextrins showed structure-selective complexation property to different guest. The stability of the trans-resveratrol complexes was in the order of ?- > ?- > ?-cyclodextrin. The cavity size of ?-cyclodextrin was too small for astilbin and taxifolin molecules, and thus they could not form complexes. The molecular size of syringic acid was too big for all cyclodextrins cavity, and no cyclodextrin could form complexes with it. Temperature studies showed that the binding constants decreased with the rise of temperature. Enthalpy and entropy values were calculated and the negative values of these parameters indicated that the complexation process was enthalpy-controlled. Van der Waals force and release of high-enthalpy water molecules from the cyclodextrins cavity played important roles in the process. PMID:23184372

Zhang, Qing-Feng; Cheung, Hon-Yeung; Shangguan, Xinchen; Zheng, Guodong

2012-12-01

338

Mixing of non-Newtonian fluids in wavy serpentine microchannel using electrokinetically driven flow.  

PubMed

A numerical investigation is performed into the mixing performance of electrokinetically driven non-Newtonian fluids in a wavy serpentine microchannel. The flow behavior of the non-Newtonian fluids is described using a power-law model. The simulations examine the effects of the flow behavior index, the wave amplitude, the wavy-wall section length, and the applied electric field strength on the mixing performance. The results show that the volumetric flow rate of shear-thinning fluids is higher than that of shear-thickening fluids, and therefore results in a poorer mixing performance. It is shown that for both types of fluid, the mixing performance can be enhanced by increasing the wave amplitude, extending the length of the wavy-wall section, and reducing the strength of the electric field. Thus, although the mixing efficiency of shear-thinning fluids is lower than that of shear-thickening fluids, the mixing performance can be improved through an appropriate specification of the flow and geometry parameters. For example, given a shear-thinning fluid with a flow behavior index of 0.8, a mixing efficiency of 87% can be obtained by specifying the wave amplitude as 0.7, the wavy-wall section length as five times the characteristic length, the nondimensional Debye-Huckel parameter as 100, and the applied electric field strength as 43.5 V/cm. PMID:22522530

Cho, Ching-Chang; Chen, Chieh-Li; Chen, Cha'o-Kuang

2012-03-01

339

Analysis of post-harvest fungicides by micellar electrokinetic chromatography.  

PubMed

A method based on solid-phase extraction (SPE) and micellar electrokinetic chromatography (MEKC) was developed for the simultaneous determination of carbendazim, imazalil, methylthiophanate, O-phenylphenol, prochloraz, procimidone, thiabendazole and triadimefon residues in grape, lettuce, orange and tomato. Selectivity and resolution were studied changing the pH and the concentration of the buffer, the type and concentration of surfactant and the methanol content in the mobile phase. A buffer consisting of 4 mM borate with 75 mM sodium cholate (pH 9.2) gave the best results. The recoveries of the fungicides in spiked fruit and vegetable samples ranged from 30 to 105%, and the limits of detection were between 0.1 and 1 mg kg(-1). The reproducibility and repeatability of the combination of SPE pretreatment and MEKC were good for all the compounds, except for imazalil and O-phenylphenol in oranges, due to some matrix compounds interfering with the separation. The method was applied to post harvest treated samples, and the fungicides were sometimes detected at concentration levels lower than maximum residue limits (MRLs). PMID:11521888

Rodríguez, R; Picó, Y; Font, G; Mañes, J

2001-07-27

340

Copper cation removal in an electrokinetic cell containing zeolite.  

PubMed

Zeolites are used in environmental remediation of soil or water to immobilize or remove toxic materials by cation exchange. An experiment was conducted to test the use a low electric field to direct the toxic cations towards the zeolite. An electrokinetic cell was constructed using carbon electrodes. Synthetic Linde Type A (LTA) zeolite was placed in the cell. Copper(II) chloride dissolved in water was used as a contaminant. The Cu(2+) concentration was measured for ten hours with and without an applied electric field. The removal of the Cu(2+) ions was accelerated by the applied field in the first two hours. For longer time, the electric field did not improve the removal rate of the Cu(2+) ions. The presence of zeolite and applied electric field complicates the chemistry near the cathode and causes precipitation of Cu(2+) ions as copper oxide on the surface of the zeolite. With increased electric field the zeolite farther away from the cathode had little cation exchange due to the higher drift velocity of the Cu(2+) ions. The results also show that, in the LTA Zeolite A pellets, the cation exchange of Cu is limited to a shell of several tens of micrometers. PMID:21109348

Elsayed-Ali, Omar H; Abdel-Fattah, Tarek; Elsayed-Ali, Hani E

2011-01-30

341

Simultaneous determination of andrographolide and dehydroandrographolide in Andrographis paniculata and Chinese medicinal preparations by microemulsion electrokinetic chromatography.  

PubMed

The present paper describes the development of a microemulsion electrokinetic chromatographic (MEEKC) method for simultaneous determination of andrographolide and dehydroandrographolide in traditional Chinese medicines and Chinese medicinal preparations. The MEEKC method involved the use of sodium dodecyl sulfate (SDS) as surfactant, heptane as organic solvent and butan-1-ol as co-solvent. The effect of temperature and pH of running buffers on separation were examined. The optimized conditions (heptane 0.81% (w/w), SDS 3.31% (w/w), butan-1-ol 6.61% (w/w) and 10mM sodium tetraborate buffer, pH 9.2) allowed a useful and good reproducible separation of the studied analytes to be achieved. PMID:15894448

Yanfang, Zhao; Xingping, Luo; Zongde, Zhai; Liren, Chen; Yongmin, Li

2006-01-23

342

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

343

Electrokinetic separation of biomolecules through multiple nano-pores on membrane  

NASA Astrophysics Data System (ADS)

We demonstrate a nanoporous membrane device integrated with an on-chip microfluidic platform for the electrokinetic separation of biomolecules. This platform offers a thin (500 nm) film of anodized aluminum oxide directly fabricated and suspended onto a silicon substrate, assembled into a compact microfluidic device. We successfully showed the electrokinetic transport of ssDNA through the nano-porous membrane under various conditions. Size exclusive biomolecular separation driven by electric field was verified with the complex of thrombin and thrombin aptamer. This architecture enables an on-chip device for binary separation and size exclusive filtration targeted to various applications such as molecular detection and purification.

Kim, Yunho; Cha, Misun; Choi, Yosep; Joo, Hyunsang; Lee, Junghoon

2013-03-01

344

Antifungal effect of zeolite-incorporated tissue conditioner against Candida albicans growth and/or acid production.  

PubMed

A new antimicrobial material, Ag-zeolite (Zeomic), was combined with a commercial tissue conditioner (GC-Soft Liner (GC); 1-5%) and, through monitoring the pH of the growth medium, examined for effects on the in vitro growth and/or acid production of Candida albicans on protein-free and saliva-coated specimens. The effect of incorporation of this agent on the physical property of the lining material was also examined according to the ISO penetration test. Comparison studies were carried out using GC, Coe Comfort (CC) or undecylenate combined GC (1-5%) specimens. Although the pH changes in the media varied depending upon the materials on which the Candida was grown, reverse sigmoidal pH curves were observed with most samples. As compared with GC, the soft lining materials showed, to some extent, an inhibitory effect on the acid production and/or the growth of C. albicans. These inhibitory effects consisted of a delay in the onset of rapid pH decline, decreases in the rate of pH change and increases in minimum pH. In most cases, the inhibitory effects of test specimens were dose-dependent, and zeolite specimens showed a significantly higher antifungal effect, followed by CC and undecylenate-combined GC; GC showed the least antifungal effect. The inhibitory effects of these materials on fungal growth were decreased by the presence of a saliva-coat, particularly with zeolite specimens and CC. However, four of eight 5%-Zeomic specimens still exhibited perfect growth inhibition in the presence of the salivary pellicle. Furthermore, test specimens containing 2-5% Zeomic showed a significantly greater effect on the delay in rapid decline of pH, as compared with the other specimens examined. In addition, the significantly higher minimum pH was observed where the yeasts were grown on 4%- and 5%-Zeomic specimens. The physical properties of all the test specimens conformed with the ISO standard as examined by penetration test. These results taken together suggest that an antimicrobial zeolite-combined tissue conditioner would be a potential aid in denture plaque control. PMID:9183028

Nikawa, H; Yamamoto, T; Hamada, T; Rahardjo, M B; Murata, H; Nakanoda, S

1997-05-01

345

Simultaneous removal of 2,4-dichlorophenol and Cd from soils by electrokinetic remediation combined with activated bamboo charcoal.  

PubMed

An in situ electrokinetic remediation technique was designed by combining the uniform electrokinetic technology with a new-type of bamboo charcoal as adsorbent. A bench-scale experiment was conducted to investigate the application of this technique for simultaneous removal of 2,4-dichlorophenol (2,4-DCP) and Cd from a sandy loam at different periodic polarity-reversals. The contaminated soil was artificially spiked with 100 mg/kg 2,4-DCP and 500 mg/kg Cd. Two modes of polarity-reversal intervals of 12 and 24 h were included. After 10.5 d of operation, about 75.97% of Cd and 54.92% of 2,4-DCP were removed from soil at intervals of 24 h, whilst only 40.13% of Cd and 24.98% of 2,4-DCP were removed at intervals of 12 h. Soil water contents under two operation modes both significantly decreased, but evenly distributed spatially. Soil pH values under two operation modes were all maintained in the range from 7.2 to 7.4, close to the initial value. The electricity consumption per day was 12.24 and 11.61 kWh/m(3)/d, respectively at polarity-reversal intervals of 12 and 24 h. In conclusion, at polarity-reversal interval of 24 h, electroremediation combined with activated bamboo charcoal was effective in simultaneous removal of 2,4-DCP and Cd from soil. Our results indicate a promising potential in in situ electroremediation of soils co-contaminated with organics and heavy metals. PMID:20006426

Ma, Jian Wei; Wang, Fa Yuan; Huang, Zheng Hong; Wang, Hui

2010-04-15

346

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

347

Experimental and numerical evidences of the observation of the Biot slow wave thanks to its electrokinetic conversion  

NASA Astrophysics Data System (ADS)

As originally described by Biot in 1956, seismic propagation in fluid-filled porous media should include two longitudinal contributions: the fast and slow P waves, the latest being commonly referred to as the ';Biot slow wave'. This seismic wave has been seldom observed in natural rocks at laboratory frequencies due to its low amplitude properties and has never been recognized at seismic frequencies due to its diffusive properties. In porous media, a part of seismic energy may also be converted into electromagnetic fields by a coupling phenomenon of electrokinetic nature: the so-called seismoelectric effect. Most seismoelectric studies focus on the observation of co-seismic or depth-converted electric fields generated by the propagation of fast P-waves, mainly to detect or to image new physico-chemical contrasts. Based on Pride's theory (1994), numerical modeling of seismo-electromagnetic wave propagation suggests that the observation of the Biot slow wave could be boosted by its electrokinetic conversion, i.e. that it would be easier to record the electric fields accompanying Biot slow waves generated by a mechanical source rather than the seismic fields. In order to confirm these numerical predictions, we designed a specific laboratory experiment involving a silica sand tank excited by using a homemade pneumatic seismic source. The investigated frequency range [0.5-5kHz] contains the Biot (transition) frequency separating the diffusive from the propagation regimes of the slow wave. Numerical seismoelectromagnetic experiments were also performed at this scale to compute the seismoelectric response in homogeneous and partially saturated sand with this acquisition configuration. The comparison of these experimental data to numerical results provides new perspectives for the detection, study and potential use of the Biot slow wave.

Bordes, C.; Garambois, S.; Brito, D.; Dietrich, M.; Holzhauer, J.

2013-12-01

348

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

349

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

SciTech Connect

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

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

2013-12-28

350

Incorporation of quantum effects for selected degrees of freedom into the trajectory-based dynamics using spatial domains.  

PubMed

The approach of defining quantum corrections on nuclear dynamics of molecular systems incorporated approximately into selected degrees of freedom, is described. The approach is based on the Madelung-de-Broglie-Bohm formulation of time-dependent quantum mechanics which represents a wavefunction in terms of an ensemble of trajectories. The trajectories follow classical laws of motion except that the quantum potential, dependent on the wavefunction amplitude and its derivatives, is added to the external, classical potential. In this framework the quantum potential, determined approximately for practical reasons, is included only into the "quantum" degrees of freedom describing light particles such as protons, while neglecting with the quantum force for the heavy, nearly classical nuclei. The entire system comprised of light and heavy particles is described by a single wavefunction of full dimensionality. The coordinate space of heavy particles is divided into spatial domains or subspaces. The quantum force acting on the light particles is determined for each domain of similar configurations of the heavy nuclei. This approach effectively introduces parametric dependence of the reduced dimensionality quantum force, on classical degrees of freedom. This strategy improves accuracy of the quantum force and does not restrict interaction between the domains. The concept is illustrated for two-dimensional scattering systems, where the quantum force is required to reproduce vibrational energy of the quantum degree of freedom. PMID:22920111

Garashchuk, Sophya; Volkov, Mikhail V

2012-08-21

351

[Effect of organic material incorporation in rice season on N2O emissions from following winter wheat growing season].  

PubMed

In a field experiment, five fertilizer treatments including chemical fertilizer (CF), rapeseed cake + chemical fertilizer (RC + CF), wheat straw + chemical fertilizer (WS + CF), cow manure + chemical fertilizer (CM + CF), and pig manure + chemical fertilizer (PM + CF), were dedicated to examine the effect of organic materials incorporation in the rice season on N2O emissions from the following winter wheat season and to assess the climatic impacts from CH4 and N2O emissions in a rice-wheat rotation. Organic material was incorporated at the same rate (225 g x m(-2)) for organic treatments at the depth of 10 cm in the soil as the basal fertilizer just before rice transplanting. An identical synthetic nitrogen fertilizer was adopted for all treatments. Results show that the seasonal amount of N20 emissions from the following wheat season differed with organic material applied in rice season. No pronounced difference in N20 emissions was found between the CF and RC + CF treatments. In contrast with the CF treatment, however, N2O emission was decreased by 15% for the WS + CF treatment, but increased by 29% and 16% for the CM + CF and PM + CF treatments, respectively. Over the entire annual rotation cycle, N2O amount was increased by 17% for the CM + CF treatment, 7% for the PM + CF treatment, and 6% for the RC + CF treatment, but decreased by 16% for the WS + CF treatment in comparison with the CF treatment. Based on total emissions of CH4 in rice season and N2O over the entire rotation cycle, the estimation of combined Global Warming Potentials (GWPs) for CH4 and N20 shows that over a 20 years horizon or a 500 years horizon, the value of annual total GWPs was ranked in the order of RC + CF > WS + CF > CM + CF > PM + CF > CF or RC + CF > CM + CF > PM + CF > WS + CF > CF. The highest, middle and the lowest value of the GWPs per unit crop grain yield occurred for the crop residue, farmyard manure and pure synthetic fertilizer treatments, respectively. Compared to the chemical fertilizer treatment, accordingly, organic material combined with chemical fertilizer application in rice season increased climatic impacts from CH4 and N20 emissions in a rice-winter wheat rotation system. PMID:16881292

Zou, Jian-wen; Huang, Yao; Zong, Liang-gang; Zheng, Xun-hua; Wang, Yue-si

2006-07-01

352

Opto-electrokinetic manipulation for high-performance on-chip bioassays.  

PubMed

This communication first demonstrates bio-compatibility of a recently developed opto-electrokinetic manipulation technique, using microorganisms. Aggregation, patterning, translation, trapping and size-based separation of microorganisms performed with the technique firmly establishes its usefulness for development of a high-performance on-chip bioassay system. PMID:23099738

Kwon, Jae-Sung; Ravindranath, Sandeep P; Kumar, Aloke; Irudayaraj, Joseph; Wereley, Steven T

2012-12-01

353

Evaluation on the Feasibility of Microbially Enhanced Electrokinetic Removal of Multiple Heavy Metals from Tailing Soil  

Microsoft Academic Search

Lab-scale experiments were conducted to evaluate the efficacy of the enhanced electrokinetics combined with anaerobic and aerobic bioleaching processes for remediation of tailing soil. The tailing soil contained multiple heavy metals, such as As, Cd, Co, Cu, Cr, Fe, Mn, Ni, Pb, and Zn. To begin with, the applicability of both anaerobic and aerobic bioleaching was investigated as a pretreatment

Keun-Young Lee; Ki-Rak Kim; Byung-Tae Lee; Ju-Yong Kim; Kyoung-Woong Kim; Soon-Oh Kim

2009-01-01

354

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

355

Electrokinetic microfluidic devices for rapid, low power drug delivery in autonomous microsystems{  

E-print Network

, intravenous, pulmonary and transdermal methods represent the traditional and often preferred routes for drugElectrokinetic microfluidic devices for rapid, low power drug delivery in autonomous microsystems, a low power and robust electroactive microwell-based implantable drug delivery system, intended for use

Erickson, David

356

Isolation of aucubin and catalpol from Melitaea cinxia larvae and quantification by micellar electrokinetic capillary chromatography  

Microsoft Academic Search

Two iridoid glycosides, aucubin and catalpol, were extracted from Melitaea cinxia larvae with hot, dilute aqueous SDS solution and then separated and quantified by micellar electrokinetic capillary chromatography. Solutions of pure aucubin and catalpol were used to optimise the separation. The extraction method was developed for a mixture of 80 larvae and single larvae were then analysed with the optimised

Johanna Suomi; Heli Sirén; Susanne K Wiedmer; Marja-Liisa Riekkola

2001-01-01

357

Concentration Polarization and Nonlinear Electrokinetic Flow near a Nanofluidic Channel Sung Jae Kim,1  

E-print Network

Concentration Polarization and Nonlinear Electrokinetic Flow near a Nanofluidic Channel Sung Jae within nanofluidic channels, with critical dimensions of 10­100 nm, have drawn a lot of attention,3], nanofluidic channels can be an ideal, well-controlled experimental platform to study nanoscale molecular

358

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...

359

A mechanistic study of arsenate removal from artificially contaminated clay soils by electrokinetic remediation.  

PubMed

Batch desorption experiments and bench-scale electrokinetic experiments were performed to elucidate the electrokinetic remediation mechanisms of arsenate from artificially contaminated kaolinite. The electrokinetic experiments in which a constant voltage was applied demonstrated that high soil pH favored arsenate remediation with respect to both the remediation time and electricity consumption. It was also demonstrated that applying a pulse voltage (1 h ON, 1 h OFF) significantly improved the electricity consumption efficiency when the soil pH was maintained at the initial value during the experiments; this trend was not observed when the soil pH was gradually increased from the cathode side. These electrokinetic experimental results, with the support of arsenate desorption data obtained from batch experiments, indicate that the remediation rate-limiting step varied with soil pH. When the soil pH was maintained at the initial value of 7.2 during the experiments, arsenate desorption was the remediation rate-limiting step rather than the migration of dissolved arsenate toward the anode. Conversely, when the cathode pH was not controlled and the soil pH was correspondingly increased gradually from the cathode side, the migration of hydroxyl and desorbed arsenate ions toward the anode played a more important role in the control of the overall remediation efficiency. PMID:23643955

Suzuki, Tasuma; Moribe, Mai; Okabe, Yohhei; Niinae, Masakazu

2013-06-15

360

ELECTROOSMOTIC FLOWS AND ELECTROMIGRATIONS DURING ELECTROKINETIC PROCESSING OF TROPICAL RESIDUAL SOIL  

Microsoft Academic Search

Saturated soft soils can be strengthened by several methods such as dewatering or adding suitable chemicals. Introduction of chemicals through electrokinetic (EK) process to strengthen a residual soil was investigated. The results of chemical tests on an elecrokinetically- treated tropical residual soil are presented. The chemical substances used as electrolytes in the experiments were aluminum chloride (Al), calcium chloride (Ca)

Kamarudin Ahmad; Khairul Anuar Kassim

361

Effect of nitrogen incorporation on improvement of leakage properties in high-k HfO{sub 2} capacitors treated by N{sub 2}-plasma  

SciTech Connect

The nitrogen incorporation into the HfO{sub 2} films with an EOT (equivalent oxide thickness) of 9 A was performed by N{sub 2}-plasma to improve the electrical properties. The dielectric properties and a leakage current characteristics of the capacitors were investigated as a function of plasma power and plasma treatment temperature. The dielectric constant of the capacitors is not influenced by nitrogen incorporation. The N{sub 2}-plasma treatment at 300 deg. C and 70 W exhibits the most effective influence on improvement of the leakage current characteristics. Leakage current density of the capacitors treated at 300 deg. C and 70 W exhibits a half order of magnitude lower than that without plasma treatment. Nitrogen incorporated into the HfO{sub 2} films possesses the intrinsic effect that drastically reduce the electron leakage current through HfO{sub 2} dielectrics by deactivating the V{sub O} (oxygen vacancy) related gap states.

Seong, Nak-Jin; Yoon, Soon-Gil; Yeom, Seung-Jin; Woo, Hyun-Kyung; Kil, Deok-Sin; Roh, Jae-Sung; Sohn, Hyun-Chul [Department of Materials Science and Engineering, Chungnam National University, Daeduk Science Town, 305-764, Daejon (Korea, Republic of); Hynix Semiconductor Inc., San 136-1 Ami-ri Bubal-eub Icheon-si Kyoungki-do, 467-701 (Korea, Republic of)

2005-09-26

362

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

363

Biosynthetic incorporation of tryptophan analogues into staphylococcal nuclease: effect of 5-hydroxytryptophan and 7-azatryptophan on structure and stability.  

PubMed Central

5-Hydroxytryptophan (5HW) and 7-azatryptophan (7AW) are analogue of tryptophan that potentially can be incorporated biosynthetically into proteins and used as spectroscopic probes for studying protein-DNA and protein-protein complexes. The utility of these probes will depend on the extent to which they can be incorporated and the demonstration that they cause minimal perturbation of a protein's structure and stability. To investigate these factors in a model protein, we have incorporated 5HW and 7AW biosynthetically into staphylococcal nuclease A, using a trp auxotroph Escherichia coli expression system containing the temperature-sensitive lambda cI repressor, Both tryptophan analogues are incorporated into the protein with good efficiency. From analysis of absorption spectra, we estimate approximately 95% incorporation of 5HW into position 140 of nuclease, and we estimate approximately 98% incorporation of 7AW, CD spectra of the nuclease variants are similar to that of the tryptophan-containing protein, indicating that the degree of secondary structure is not changed by the tryptophan analogues. Steady-state fluorescence data show emission maxima of 338 nm for 5HW-containing nuclease and 355 nm for 7AW-containing nuclease. Time-resolved fluorescence intensity and anisotropy measurements indicate that the incorporated 5HW residue, like tryptophan at position 140, has a dominant rotational correlation time that is approximately the value expected for global rotation of the protein. Guanidine-hydrochloride-induced unfolding studies show the unfolding transition to be two-state for 5HW-containing protein, with a free energy change for unfolding that is equal to that of the tryptophan-containing protein. In contrast, the guanidine-hydrochloride-induced unfolding of 7AW-containing nuclease appears to show a non-two-state transition, with the apparent stability of the protein being less than that of the tryptophan form. PMID:9070451

Wong, C. Y.; Eftink, M. R.

1997-01-01

364

Effects of magnetic nanoparticle-incorporated human bone marrow-derived mesenchymal stem cells exposed to pulsed electromagnetic fields on injured rat spinal cord.  

PubMed

Transplanting mesenchymal stem cells into injured lesions is currently under study as a therapeutic approach for spinal cord injury. In this study, the effects of a pulsed electromagnetic field (PEMF) on injured rat spinal cord were investigated in magnetic nanoparticle (MNP)-incorporated human bone marrow-derived mesenchymal stem cells (hBM-MSCs). A histological analysis revealed significant differences in MNP-incorporated cell distribution near the injured site under the PEMF in comparison with that in the control group. We confirmed that MNP-incorporated cells were widely distributed in the lesions under PEMF. The results suggest that MNP-incorporated hBM-MSCs were guided by the PEMF near the injured site, and that PEMF exposure for 8 H per day over 4 weeks promoted behavioral recovery in spinal cord injured rats. The results show that rats with MNP-incorporated hBM-MSCs under a PEMF were more effective on the Basso, Beattie, and Bresnahan behavioral test and suggest that the PEMF enhanced the action of transplanted cells for recovery of the injured lesion. PMID:24033637

Cho, Hyunjin; Choi, Yun-Kyong; Lee, Dong Heon; Park, Hee Jung; Seo, Young-Kwon; Jung, Hyun; Kim, Soo-Chan; Kim, Sung-Min; Park, Jung-Keug

2013-01-01

365

[Integrated effect of incorporation with different organic manures on CH4 and N2O emissions from rice paddy].  

PubMed

Field experiment was conducted in 2001 rice growing season to understand the effect of organic manure application on CH4 and N2O emissions. Five treatments of fertilizer including urea and NH4HCO3 used as chemical fertilizer (CF), chemical fertilizer + pig manure (CF + PM), chemical fertilizer + cow manure (CF + CM), chemical fertilizer + rapeseed cake (CF + RC) and chemical fertilizer + wheat straw (CF + WS) were dedicated to this experiment. Results from the field observations indicated that application of the organic manure did not change the seasonal pattern of CH4 and N2O emissions but significantly affected the seasonal amounts. Seasonal amount of CH4 emission from the treatments of CF + CM, CF + RC and CF + WS was respectively 45%, 252% and 250% higher than that from the treatment of CF, but the application of pig manure (CF + PM) did not significantly influence the CH4 emission. The N2O emissions, on the other hand, were reduced by 18%, 21% and 18% for the treatments of CF + PM, CF + CM and CF + WS, respectively. Incorporation of rapeseed cake enhanced the N2O emission, yielding an increment of 22%. On a time scale of 20-year period, the integrated global warming potential (GWP) of CH4 + N2O released during the rice growing season for the treatments of CF + RC, CF + WS and CF + CM was respectively 154%, 136% and 17% higher than that for the CF treatment, while a reduction of 10% was obtained for the CF + PM treatment. The calculation of the GWP per unit rice grain yield suggested that the application of pig manure took the slight advantages not only in reducing the GWP but also in improving the grain yield. PMID:14551949

Zou, Jianwen; Huang, Yao; Zong, Lianggang; Wang, Yuesi; Sass, Ronald L

2003-07-01

366

The effects of functional magnetic nanotubes with incorporated nerve growth factor in neuronal differentiation of PC12 cells  

NASA Astrophysics Data System (ADS)

In this in vitro study the efficiency of magnetic nanotubes to bind with nerve growth factor (NGF) and the ability of NGF-incorporated magnetic nanotubes to release the bound NGF are investigated using rat pheochromocytoma cells (PC12 cells). It is found that functional magnetic nanotubes with NGF incorporation enabled the differentiation of PC12 cells into neurons exhibiting growth cones and neurite outgrowth. Microscope observations show that filopodia extending from neuron growth cones were in close proximity to the NGF-incorporated magnetic nanotubes, at times appearing to extend towards or into them. These results show that magnetic nanotubes can be used as a delivery vehicle for NGF and thus may be exploited in attempts to treat neurodegenerative disorders such as Parkinson's disease with neurotrophins. Further neurite outgrowth can be controlled by manipulating magnetic nanotubes with external magnetic fields, thus helping in directed regeneration.

Xie, Jining; Chen, Linfeng; Varadan, Vijay K.; Yancey, Justin; Srivatsan, Malathi

2008-03-01

367

Effect of edible coating ingredients incorporated into predusting mix on moisture content, fat content and consumer acceptability of fried breaded product  

Microsoft Academic Search

The effect of edible coatings and their concentrations on moisture and fat contents of fried breaded potato were investigated. Hydroxypropyl methylcellulose (HPMC), methylcellulose (MC) or wheat gluten (WG) were incorporate into predusting mix to achieve coating material concentration of 3-12% (w\\/w). Blanched potatoes were first coated with predust- ing mix and followed sequentially by battering, breading and deep frying at

Worapong Usawakesmanee; Manjeet S. Chinnan; Phaisan Wuttijumnong; Anuvat Jangchud

368

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

369

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

370

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

371

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

372

Simultaneous removal of 2,4-dichlorophenol and Cd from soils by electrokinetic remediation combined with activated bamboo charcoal  

Microsoft Academic Search

An in situ electrokinetic remediation technique was designed by combining the uniform electrokinetic technology with a new-type of bamboo charcoal as adsorbent. A bench-scale experiment was conducted to investigate the application of this technique for simultaneous removal of 2,4-dichlorophenol (2,4-DCP) and Cd from a sandy loam at different periodic polarity-reversals. The contaminated soil was artificially spiked with 100mg\\/kg 2,4-DCP and

Jian Wei Ma; Fa Yuan Wang; Zheng Hong Huang; Hui Wang

2010-01-01

373

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

374

Cosolvent-enhanced Desorption and Transport of Heavy Metals and Organic Contaminants in Soils during Electrokinetic Remediation  

Microsoft Academic Search

Numerous sites are contaminated with both heavy metals and polycyclic aromatic hydrocarbons (PAHs) and the technologies to\\u000a treat such mixed contaminants are very limited. Electrokinetic remediation has the potential to remediate mixed contaminants\\u000a in soils, including low permeability soils; however, the efficiency of this technology depends on the extracting solution\\u000a employed. Previous studies on electrokinetic remediation have focused on the

Kranti Maturi; Krishna R. Reddy

2008-01-01

375

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

376

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

377

Oral consumption of electrokinetically modified water attenuates muscle damage and improves postexercise recovery.  

PubMed

The purpose of this study was to assess the effects of consuming electrokinetically modified water (EMW) on attenuating muscle damage and improving functional recovery following a single bout of isokinetic resistance exercise. Subjects were randomly assigned to an EMW (n = 20) or a placebo control (n = 20) group. Subjects consumed EMW or placebo water daily for 23 days. On day 19 subjects completed an exercise protocol for the biceps brachii to induce muscle damage. The protocol consisted of three sets of 20 repetitions using concentric and eccentric contractions of the elbow flexors. Blood draw and clinical measurements were performed preexercise as well as 24, 48, and 96 h postexercise. Clinical measures included maximal isometric strength, muscle soreness, pain with elbow extension, relaxed elbow angle (RANG), and self-report arm disability. Plasma samples were analyzed to determine concentrations of creatine kinase (CK) and high-sensitivity C-reactive protein (hsCRP). Pain with elbow extension and self-report arm disability were significantly higher in the placebo group compared with the EMW group at 48 h (P < 0.01) and 96 h (P < 0.01) after exercise, while RANG was significantly higher in the EMW group compared with placebo at 48 h (P < 0.01) and 96 h (P < 0.01) after exercise. Similarly, plasma concentrations for hsCRP and CK were significantly lower in the EMW group compared with placebo at 48 h (P < 0.05) and 96 h (P < 0.01) after exercise. Oral consumption of EMW significantly reduced exercise-induced muscle damage and inflammation and improved functional recovery. PMID:23580602

Borsa, Paul A; Kaiser, Kelly L; Martin, Jeffrey S

2013-06-15

378

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

379

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

380

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

381

PRELIMINARY STUDY OF ANTIMICROBIAL (AM) EFFECTS OF STARCH-BASED FILM INCORPORATED WITH NISIN, LYSOZYMES AND LAURIC ACID  

Microsoft Academic Search

Active Packaging (AP) concept is a current trend in food packaging industries. An antimicrobial (AM) Active Packaging can be made by incorporating and immobilizing suitable AM agents into food packages and applying a bio switch concept. By that, the mechanism of antimicrobial release between the developed bio-switch particles and the stimulus of a microbial contamination can be studied. A starch-based

Nozieana Khairuddin; Ida Idayu Muhamad

382

Wang S. Zhou W. and Cui S. Simultaneous Determination Catecholamines Micellar Electrokinetic Chromatography Laser-Induced Fluorescence Detection International Conference Chemistry Chemical Engineering  

EPA Pesticide Factsheets

Search instead for Wang S. Zhou W. and Cui S. Simultaneous Determination Catecholamines Micellar Electrokinetic Chromatography Laser-Induced Fluorescence Detection International Conference Chemistry Chemical Engineering ?

383

The Effects of Incorporating Web-assisted Learning with Team Teaching in Seventh-grade Science Classes  

Microsoft Academic Search

Due to the implementation of a 9-year integrated curriculum scheme in Taiwan, research on team teaching and web-based technology appears to be urgent. The purpose of this study was incorporated web-assisted learning with team teaching in seventh-grade science classes. The specific research question concerned student performance and attitudes about the teaching method. Two certified science teachers and four classes of

2006-01-01

384

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

385

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

Microsoft Academic Search

Incorporation of soy protein isolate (SPI) at 0, 15, and 25% levels in buffalo meat was investigated for production, quality\\u000a and shelf life evaluation of emulsion sausage (ES). Quality of ES was evaluated by pH, moisture content, thiobarbituric acid\\u000a (TBA) number, total plate count (TPC), and Yeast and mold count, sensory, characteristics and instrumental colour and texture\\u000a measurements. It was

S. Ahmad; J. A. Rizawi; P. K. Srivastava

2010-01-01

386

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

387

Effect of Incorporating Project-Based Learning into the Development of an English Short Play for Children  

Microsoft Academic Search

The purpose of the study was mainly to incorporate project-based learning into the development of an English short play as a teaching material to promote children¡¦s (second language learners) English learning attitude and interests. The subjects of this study were five senior English-majored students as a team and 30 4th grade elementary school students. After the English short play was

Ru-Chu Shih; Charles Papa; Mei-Mei Chang; Tien-Hsin Hsin

2012-01-01

388

Effect on days of lactation and methionine hydroxy analog on incorporation of plasma fatty acids into plasma triglycerides  

Microsoft Academic Search

Methionine hydroxy analog has been proposed to stimulate hepatic lipoprotein synthesis and incorporation of plasma fatty acids into plasma triglyceride. Seven cows were fed diets containing 0 to 30 g analog\\/d starting 14 d prepartum. At approximately 30 and 60 d postpartum, cows were continuously infused intravenously with 1-(¹⁴C)palmitic acid for 160 min to achieve steady-state labeling of plasma fatty

David L. Pullen; R. S. Emergy; D. L. Palmquist

1989-01-01

389

Pseudo-electrokinetic packing of high efficiency columns for capillary electrochromatography.  

PubMed

An improved and easy electrokinetic packing procedure is presented for the production of stable capillary columns suitable for capillary electrochromatography (CEC). In pseudo-electrokinetic packing a high electric field is used in conjunction with a hydrodynamic flow. The packing of silica-based reversed-phase columns can be achieved with basic, commercially available capillary electrophoresis (CE) equipment in approximately 15 min. The procedure is robust and a high success rate is achieved. No steps which might damage the stationary phase are involved and only a minimum amount of packing material is required. Columns packed according to the developed procedure are operated at high electric field strengths during the CEC separation, without the application of a stabilising pressure. Columns are stable for at least hundred runs and were tested using mixtures of polycyclic aromatic hydrocarbons and positively charged drugs. Separations were performed in a relatively high conducting ammonium acetate buffer, with efficiencies of up to 283000 plates/m. PMID:10757307

Stol, R; Mazereeuw, M; Tjaden, U R; van der Greef, J

2000-03-24

390

Capillary electrokinetic separations with optical detection. Technical progress report, February 1, 1993--January 31, 1996  

SciTech Connect

The seminal work of Jorgenson in 1981 ushered in the modern era of capillary electrophoresis (CE). Since that time, research activities involving capillary electrokinetic methods of separation have grown exponentially. Numerous conferences, symposia, monographs, and dedicated journals attest to the maturing of these techniques. While many of the obvious approaches have been explored, and instrumentation is reasonably well-developed, the full potential of CE has clearly not yet been reached. Moreover, CE techniques are not universally accepted as desirable alternatives to traditional chromatographic and electrophoretic methods of separation. Thus, it is likely that research into various aspects of capillary electrokinetic separations will continue at a torrid pace for at least the remainder of this decade.

Sepaniak, M.J.

1998-02-01

391

DETERMINATION OF ANTI-INFLAMMATORY DRUGS IN RIVER WATER BY SWEEPING-MICELLAR ELECTROKINETIC CAPILLARY CHROMATOGRAPHY  

Microsoft Academic Search

This paper describes a simple and sensitive sweeping-micellar electrokinetic chromatography (sweeping-MEKC) method for the preconcentration and separation of five non-steroidal anti-inflamatory drugs (NSAIDs): ibuprofen, fenoprofen, naproxen, diclofenac sodium, and ketoprofen. We have optimized the sweeping conditions, including the composition of the sample matrix and the sample injection time. With this sweeping method, about 900- and 5380- fold improvements in peak

Irene Maijó; Francesc Borrull; Marta Calull; Carme Aguilar

2012-01-01

392

Electrokinetics as an alternative to neutron reflectivity for evaluation of segment density distribution in PEO brushes.  

PubMed

Unravelling details of charge, structure and molecular interactions of functional polymer coatings defines an important analytical challenge that requires the extension of current methodologies. In this article we demonstrate how streaming current measurements interpreted with combined self consistent field (SCF) and soft surface electrokinetic theories allow the evaluation of the segment distribution within poly(ethylene oxide) (PEO) brushes beyond the resolution limits of neutron reflectivity technique. PMID:25144904

Zimmermann, Ralf; Romeis, Dirk; Bihannic, Isabelle; Cohen Stuart, Martien; Sommer, Jens-Uwe; Werner, Carsten; Duval, Jérôme F L

2014-10-21

393

Wetting behaviour, moisture up-take and electrokinetic properties of lignocellulosic fibres  

Microsoft Academic Search

The wetting and moisture up-take behaviour, as well as the electrokinetic properties of various lignocellulosic fibres were\\u000a characterised. Knowledge of surface and water uptake properties of this kind of materials will help to tailor their potential\\u000a use in different end user applications. The surface tension of the fibres was determined from wetting measurements using the\\u000a capillary rise technique. The wetting

Alexis Baltazar-y-Jimenez; Alexander Bismarck

2007-01-01

394

Factors influencing the electrokinetic dispersion of PAH-degrading bacteria in a laboratory model aquifer  

Microsoft Academic Search

Despite growing interest in the electro-bioremediation of contaminated soil it is still largely unknown to which degree weak\\u000a electric fields influence the fate of contaminant-degrading microorganisms in the sub-surface. Here we evaluate the factors\\u000a influencing the electrokinetic transport and deposition of fluorene-degrading Sphingomonas sp. LB126 in a laboratory model aquifer exposed to a direct current (DC) electric field (1 V cm?1)

L. Shi; S. Müller; H. Harms; L. Y. Wick

2008-01-01

395

INFLUENCE OF ELECTROKINETIC PROCESSING OF A TROPICAL SOIL ON THE PHS OF THE ELECTROLYTES  

Microsoft Academic Search

The pH values of different anolytes and catholytes during electrokinetic (EK) processing of a tropical residual soil were investigated in laboratory. Four opened-anode and opened-cathode systems with different types of catholytes and anolytes were examined. Aluminium chloride, calcium chloride and phosphoric acid were used as electrolytes besides distilled water. Compressed soil samples, up to 90% of the maximum dry density

Kamarudin Ahmad; Khairul Anuar Kassim; Mohd Raihan Taha; Bangi Selangor

2005-01-01

396

Using sweeping-micellar electrokinetic chromatography to determine melamine in food  

Microsoft Academic Search

This study developed a sweeping-micellar electrokinetic chromatography (sweeping-MEKC) method for fast screening of melamine in food. In order to optimise parameters with multiple responses in parallel, face-centred cube central composite design (FCD) was employed to search for the optimum conditions of the sweeping-MEKC. The optimum background electrolyte was composed of 45mM phosphoric acid and 175mM sodium dodecyl-sulfate with the addition

Wen-Chi Wu; I-Lin Tsai; Shao-Wen Sun; Ching-Hua Kuo

2011-01-01

397

Method development for sensitive determination of nisin in food products by micellar electrokinetic chromatography  

Microsoft Academic Search

A rapid and sensitive micellar electrokinetic chromatography (MEKC) method has been developed for the identification and quantification of nisin in food products. Factors such as micelle concentration, pH, and concentration of the buffer were investigated in order to determine the optimum conditions for the analysis. Using optimised conditions of a background electrolyte containing 50mM sodium phosphate, 80mM sodium dodecyl sulphate

Laiel C. Soliman; Kingsley K. Donkor

2010-01-01

398

Effect of Substrate Orientation on the Growth Rate, Surface Morphology and Silicon Incorporation on GaSb Grown by Metal-Organic Vapor Phase Epitaxy  

SciTech Connect

The growth and dopant incorporation during metal-organic vapor phase epitaxy (MOVPE) strongly depends on the orientation of the starting substrates. MOVPE of Si-doped GaSb layers on (100), (111)B and (111)A substrates were used to investigate the effect of orientation on the growth rate, the surface morphology and the silicon incorporation. orientation dependence of growth rates was studied as a function of temperature and V/III ratio. As the V/III ratios increases, the growth rate on the (111)B oriented substrate decreases, whereas that on the (111)A oriented substrate increases. The surface morphology on different substrates was studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Flat-top hexagonal hillocks were observed on (111)B surface, and the growth was by step-flow on these facets. A surface kinetic growth model has been proposed to describe the growth features observed on (111)B surfaces. Finally, the orientation dependence of silicon incorporation was studied by secondary ion mass spectrometry (SIMS) and Hall measurements. It was found that the silicon incorporation rate was four times higher on (100) oriented surface than on (111)B oriented substrates. Although no conduction type switch was found on (111)B oriented substrate, throughout the Si doping range studied, a Ga slightly rich growth condition might be one of the factors accounting for the discrepancy between theoretical prediction and experimental results.

Jian Yu; Ishwara B. Bhat

2004-01-12

399

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

400

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

401

In situ electrokinetic control of moisture and nutrients in unsaturated soils  

SciTech Connect

Many DOE facilities have unsaturated soils contaminated with metals and organic solvents. Because of the large volumes, in situ remediation is often the most economically attractive remediation technique. The success of many in situ treatment technologies depends critically on the degree to which the movement of water and desired ions can be engineered in the vadose zone. Bioremediation efforts in the vadose zone are limited by the ability to provide moisture and nutrients to contaminant-metabolizing microorganisms. An in situ electrokinetic remediation process has been developed at Sandia National Laboratories (SNL) for use in unsaturated soils, and is presently undergoing field demonstration. The electrokinetic process is not limited by low soil permeabilities and, therefore, provides a level of control not achievable by hydraulic means. Moisture is added to the subsurface in a controlled fashion such that the field capacity is never exceeded, preventing the unwanted mobilization of dissolved contaminants by saturated wetting fronts. The Sandia electrokinetic process can potentially transport both water and nutrients for bioremediation efforts and is compatible with vapor phase in situ techniques such as bioventing. The approach should as bioventing. The approach should lend itself to the directed transport of biodegradable chelating agents and complexed metals from contaminated soils.

Lindgren, E.R.; Brady, P.V.

1994-12-31

402

Rigid-cage effects on the optical properties of the dye 3,3'-diethyloxadicarbocyanine incorporated in silica-gel glasses  

Microsoft Academic Search

We investigated the optical properties of the saturable absorber 3,3?-diethyloxadicarbocyanine iodide incorporated in a matrix of silica-gel glass by the sol-gel technique. Absorption, emission, and fluorescence lifetime were studied as functions of the densification procedures. With respect to the liquid solutions, we observed a strong quenching of the P-isomer luminescence and an increase of the N-isomer fluorescence lifetime. These effects

M. Casalboni; R. Senesi; P. Prosposito; F. de Matteis; R. Pizzoferrato

1997-01-01

403

Effect of nickel incorporation on structural, nanomechanical and biocompatible properties of amorphous hydrogenated carbon thin films prepared by low energy biased target ion beam deposition  

Microsoft Academic Search

Nickel incorporated amorphous hydrogenated carbon (Ni\\/a:C–H) thin films were deposited onto the Si substrates via biased target ion beam sputtering of nickel combined with reactive ion beam deposition of a:C–H using CH4\\/Ar gas mixture. The effects of Ni doping and target bias voltage on the microstructure and mechanical properties of the as-deposited films were investigated by means of X-ray photoelectron

P. Vijaibharathy; Yin-Yu Chang; D. Nataraj; Q. Yang; Sheng-Min Yang; D. Mangalaraj; Lei Yang; Thomas J. Webster

2010-01-01

404

Relative influences of solution composition and presence of intracrystalline proteins on magnesium incorporation in calcium carbonate minerals: Insight into vital effects  

NASA Astrophysics Data System (ADS)

Biogenic calcites may contain considerable magnesium concentrations, significantly higher than those observed in inorganic calcites. Control of ion concentrations in the calcifying space by transport systems and properties of the organic matrix of mineralization are probably involved in the incorporation of high magnesium quantities in biogenic calcites, but their relative effects have never been quantified. In vitro precipitation experiments performed at different Mg/Ca ratios in the solution and in the presence of soluble organic matrix macromolecules (SOM) extracted from sea urchin tests and spines showed that, at a constant temperature, magnesium incorporation in the precipitated minerals was mainly dependent on the Mg/Ca ratio of the solution. However, a significant increase in magnesium incorporation was observed in the presence of SOM compared with control experiments. Furthermore, this effect was more pronounced with SOM extracted from the test, which was richer in magnesium than the spines. According to SEM observations, amorphous calcium carbonate was precipitated at high Mg/Casolution. The observed predominant effect of Mg/Casolution, probably mediated in vivo by ion transport to and from the calcifying space, was suggested to induce and stabilize a transient magnesium-rich amorphous phase essential to the formation of high magnesium calcites. Aspartic acid rich proteins, shown to be more abundant in the test than in the spine matrix, further stabilize this amorphous phase. The involvement of the organic matrix in this process can explain the observation that sympatric organisms or even different skeletal elements of the same individual present different skeletal magnesium concentrations.

Hermans, Julie; André, Luc; Navez, Jacques; Pernet, Philippe; Dubois, Philippe

2011-03-01

405

Evaluation of sintering effects on SiC-incorporated UO2 kernels under Ar and Ar-4%H2 environments  

NASA Astrophysics Data System (ADS)

Silicon carbide (SiC) is suggested as an oxygen getter in UO2 kernels used for tristructural isotropic (TRISO) particle fuels and to prevent kernel migration during irradiation. Scanning electron microscopy and X-ray diffractometry analyses performed on sintered kernels verified that an internal gelation process can be used to incorporate SiC in UO2 fuel kernels. Even though the presence of UC in either argon (Ar) or Ar-4%H2 sintered samples suggested a lowering of the SiC up to 3.5-1.4 mol%, respectively, the presence of other silicon-related chemical phases indicates the preservation of silicon in the kernels during sintering process. UC formation was presumed to occur by two reactions. The first was by the reaction of SiC 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. A slightly higher density and UC content were observed in the sample sintered in Ar-4%H2, but both atmospheres produced kernels with ˜95% of theoretical density. It is suggested that incorporating CO in the sintering gas could prevent UC formation and preserve the initial SiC content.

Silva, Chinthaka M.; Lindemer, Terrence B.; Hunt, Rodney D.; Collins, Jack L.; Terrani, Kurt A.; Snead, Lance L.

2013-11-01

406

Effect of a smartphone application incorporating personalized health-related imagery on adherence to antiretroviral therapy: a randomized clinical trial.  

PubMed

Abstract 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

407

Coupled lattice Boltzmann method for simulating electrokinetic flows: A localized scheme for the Nernst-Plank model  

NASA Astrophysics Data System (ADS)

We present a coupled lattice Boltzmann method (LBM) to solve a set of model equations for electrokinetic flows in micro-/nano-channels. The model consists of the Poisson equation for the electrical potential, the Nernst-Planck equation for the ion concentration, and the Navier-Stokes equation for the flows of the electrolyte solution. In the proposed LBM, the electrochemical migration and the convection of the electrolyte solution contributing to the ion flux are incorporated into the collision operator, which maintains the locality of the algorithm inherent to the original LBM. Furthermore, the Neumann-type boundary condition at the solid/liquid interface is then correctly imposed. In order to validate the present LBM, we consider an electro-osmotic flow in a slit between two charged infinite parallel plates, and the results of LBM computation are compared to the analytical solutions. Good agreement is obtained in the parameter range considered herein, including the case in which the nonlinearity of the Poisson equation due to the large potential variation manifests itself. We also apply the method to a two-dimensional problem of a finite-length microchannel with an entry and an exit. The steady state, as well as the transient behavior, of the electro-osmotic flow induced in the microchannel is investigated. It is shown that, although no external pressure difference is imposed, the presence of the entry and exit results in the occurrence of the local pressure gradient that causes a flow resistance reducing the magnitude of the electro-osmotic flow.

Yoshida, Hiroaki; Kinjo, Tomoyuki; Washizu, Hitoshi

2014-10-01

408

Liposome electrokinetic chromatography based in vitro model for early screening of the drug-induced phospholipidosis risk.  

PubMed

Drug-induced phospholipidosis (PLD) is a storage disorder of lysosomes characterized by the excessive accumulation of phospholipids as a result of improper medical treatments. Although few evidences have supported that PLD can induce significant pathological consequences, this potential toxicity indeed can put off the drug discovery process. In this research, a high-throughput liposome electrokinetic chromatography (LEKC) method was validated to evaluate the PLD risk of drug candidates by screening drug-phospholipid interaction, which correlates to the phospholipidosis inducing risk. A statistical analysis based on the Spearman's correlation test showed that the retention factors (log k) of the tested drugs in the LEKC system and the literature reported in vivo and in vitro PLD data were highly correlated. In order to investigate the predictability of LEKC, the effect of liposome composition such as the molar ratio of phospholipids and the addition of cholesterol were also discussed in this study. The results indicated that the LEKC method could offer a fast, reliable and cost-effective screening tool for early prediction of the PLD inducing potential of drug candidates. PMID:24814828

Wang, Tingting; Feng, Ying; Jin, Xiaohan; Fan, Xuxin; Crommen, Jacques; Jiang, Zhengjin

2014-08-01

409

High Mg effective incorporation in Al-rich AlxGa1 - xN by periodic repetition of ultimate V/III ratio conditions.  

PubMed

According to first-principles calculations, the solubility of Mg as a substitute for Ga or Al in AlxGa1 - xN bulk is limited by large, positive formation enthalpies. In contrast to the bulk case, the formation enthalpies become negative on AlxGa1 - xN surface. In addition, the N-rich growth atmosphere can also be favorable to Mg incorporation on the surface by changing the chemical potentials. On the basis of these special features, we proposed a modified surface engineering technique that applies periodical interruptions under an ultimate V/III ratio condition (extremely N-rich), to enhance Mg effective incorporation. By optimizing the interruption conditions (2 nm interruption interval with 2 s interruption time), the enhancement ratio can be up to about 5 in the Al0.99Ga0.01N epilayer. PMID:24444104

Zheng, Tongchang; Lin, Wei; Cai, Duanjun; Yang, Weihuang; Jiang, Wei; Chen, Hangyang; Li, Jinchai; Li, Shuping; Kang, Junyong

2014-01-01

410

High Mg effective incorporation in Al-rich Al x Ga1 - x N by periodic repetition of ultimate V/III ratio conditions  

PubMed Central

According to first-principles calculations, the solubility of Mg as a substitute for Ga or Al in Al x Ga1 – x N bulk is limited by large, positive formation enthalpies. In contrast to the bulk case, the formation enthalpies become negative on Al x Ga1 – x N surface. In addition, the N-rich growth atmosphere can also be favorable to Mg incorporation on the surface by changing the chemical potentials. On the basis of these special features, we proposed a modified surface engineering technique that applies periodical interruptions under an ultimate V/III ratio condition (extremely N-rich), to enhance Mg effective incorporation. By optimizing the interruption conditions (2 nm interruption interval with 2 s interruption time), the enhancement ratio can be up to about 5 in the Al0.99Ga0.01N epilayer. PMID:24444104

2014-01-01

411

Effect of oxygen incorporation in a-plane GaN on p-type ohmic contact property  

NASA Astrophysics Data System (ADS)

We report on the origin of the non-ohmic behavior of Ni/Au-based p-type contacts on a nonpolar a-plane GaN layer. The contact properties of Ga-polar c-plane GaN and nonpolar a-plane GaN are compared. While the Ga-polar c-plane shows ohmic-contact properties in the Ni/Au contact after heat treatment, the nonpolar a-plane shows rectifying characteristics both before and after heat treatment. We determined the reasons why the two planes show substantial differences in contact properties using various tools. We conclude that the differences originated from the oxygen incorporation preference resulting in gallium oxide formation at the interface of nonpolar a-plane GaN.

Jung, Ki-Chang; Lee, Inwoo; Park, Jaehyoung; Bae, Hyojung; Kim, Chung Yi; Shin, Hui-Youn; Kim, Hyung-Gu; Jeon, Jina; Jung, S.; Choi, Yoon-Ho; Lee, Jung-Soo; Ha, Jun-Seok

2014-09-01

412

Effects of dicyclohexylamine on polyamine biosynthesis and incorporation into turnip yellow mosaic virus in Chinese cabbage protoplasts infected in vitro  

SciTech Connect

The authors have reported that protoplasts from plants infected with turnip yellow mosaic virus (TYMV) continue to produce virus in culture and that newly formed virus particles contained predominantly newly synthesized spermidine and spermine. They now report similar results with healthy protoplasts infected in vitro, in which essentially all of the virus is newly formed. Again, newly synthesized spermidine and spermine were preferentially incorporated into virus. DCHA inhibited spermidine synthesis by 85%, leading in 20 hr to a 60% depletion of the cellular spermidine and a 30% reduction in the amount of spermidine per virion. Spermine synthesis increased, however, producing a 40% increase in cellular spermine and 50-100% increase in the amount of spermine per virion. Thus, in spite of spermidine depletion, the total positive charge contributed by polyamines to the virus was essentially conserved.

Balint, R.; Cohen, S.S.

1985-07-15

413

Effect of incorporation of mushroom (Pleurotus sajor-caju) powder on quality characteristics of Papad (Indian snack food).  

PubMed

Papad is familiarly known as an Indian food adjunct or snack food. In this study, attempts have been made to increase the protein, minerals and crude fibre content of the papad with incorporation of Pleurotus sajor-caju powder to develop a novel snack food. Mushroom powder was added in different proportions with other ingredients of the papad and the prepared papad was subjected to physicochemical and sensorial analyses. Mushrooms pretreated with 1% potassium metabisulphite followed by whey treatment had better colour and reduced drying time. Drying at 50°C produced more amount of mushroom powder (350 ?) and had higher acceptability of rehydrated samples. The papad enriched with 20% mushroom powder showed increased values of protein (15.8%), minerals (38.87%) and crude fibre (218.18%) content and had maximum sensory score. Therefore, papad supplemented with oyster mushroom powder may help to reduce protein malnutrition, constipation and mineral deficiency disorders. PMID:22574961

Parab, D N; Dhalagade, J R; Sahoo, A K; Ranveer, R C

2012-11-01

414

Effect of Sn atoms on incorporation of vacancies in epitaxial Ge1-xSnx film grown at low temperature  

NASA Astrophysics Data System (ADS)

The anomalous increase and decrease in the S-parameters of Doppler broadening spectroscopy in positron annihilation spectroscopy in a narrow range of Sn atom content were detected in a Ge1-xSnx thin film grown by MBE at low temperatures. The increase can be explained in terms of vacancies when the target content of 1.7% Sn atoms is incorporated in a Ge matrix, owing to the binding nature between them. However, the S-parameters were markedly decreased when the target content of Sn atoms in the film grown at the same temperature was 0.1%. These changes in the S-parameters correspond to the carrier concentrations obtained by Hall measurements.

Kamiyama, Eiji; Nakagawa, Satoko; Sueoka, Koji; Ohmura, Takuma; Asano, Takanori; Nakatsuka, Osamu; Taoka, Noriyuki; Zaima, Shigeaki; Izunome, Koji; Kashima, Kazuhiko

2014-02-01

415

Microemulsion electrokinetic chromatography: an application for the simultaneous determination of suspected fragrance allergens in rinse-off products.  

PubMed

A mixture of 18 neutral UV-active compounds with different characteristics of polarity was determined by capillary electrophoresis using a pseudostationary phase constituted by a microemulsion. The test analytes were volatile fragrance compounds, included in a list of 24 chemicals classified as suspected allergens according to Directive 2003/15/CE. The considered compounds were detected at 195 nm and p-anisaldehyde was chosen as internal standard. The background electrolyte consisted of a standard microemulsion made of 90.95% 10mM borax buffer, pH 9.2, 1.05% n-heptane, 8.00% SDS/n-butanol in 1:2 ratio, to which 40 mM methyl-?-cyclodextrin was added. Temperature and voltage were set at 20 °C and 25 kV, respectively. These experimental conditions allowed separation of the compounds to be obtained in about 20 min. The method was applied to real samples made up of rinse-off scented products. The results obtained using the standard microemulsion as pseudostationary phase showed its high resolution power, capable of effectively separating a complex mixture of analytes. Microemulsion electrokinetic chromatography was confirmed to have a great potential for different analytical challenges, holding up the possibility of using this technique as a good and complementary alternative to HPLC methods for routine analysis. PMID:21035646

Furlanetto, Sandra; Orlandini, Serena; Giannini, Iacopo; Pasquini, Benedetta; Pinzauti, Sergio

2010-11-15

416

Intracellular delivery method based on a combination of electrokinetic forces and vibration-assisted cell membrane perforation  

NASA Astrophysics Data System (ADS)

The introduction of biological macromolecules such as DNA, RNA, and proteins into living cells plays a crucial role in the fundamental analysis of cellular functions and mechanisms in living systems. Therefore, we have been developing an effective platform for the in vitro manipulation and analysis of biological cells at the single-cells. In this paper, we successfully demonstrated a novel intracellular delivery method of DNA into living HeLa cells via a glass micropipette based on DC-biased AC electrokinetically driven forces. We also proposed a vibration-assisted insertion method for penetrating a cell membrane to reduce cell damage. Preliminary insertion tests on homemade SICM system and FEM simulations revealed that the application of the mechanical oscillation can reduce the deformation of cells probably due to an increase in their viscous resistance. Moreover, we also found that a change in the ion current during the insertion process allows us to detect the instant when the micropipette tip penetrates the cell membrane.

Shibata, Takayuki; Ito, Yasuharu; Ozawa, Tatsuya; Nagai, Moeto; Kawashima, Takahiro

2014-02-01

417

Separation and determination of toxic pyrrolizidine alkaloids in traditional Chinese herbal medicines by micellar electrokinetic chromatography with organic modifier.  

PubMed

A simple and rapid micellar electrokinetic chromatography (MEKC) method was developed for the separation and determination of four toxic pyrrolizidine alkaloids (PAs) (senkirkine, senecionine, retrorsine, and seneciphylline) in two traditional Chinese herbal medicines (Qian liguang and Kuan donghua). Separation was performed in the running buffer consisting of 20 mM borate, 30 mM SDS, and 20% methanol at pH 9.1. With the optimized separation conditions, four PAs were separated in 17 min by a single run. The calibration curves showed good linearity with correlation efficiencies (R(2)) between 0.9940 and 0.9988. RSDs in migration time and peak area were 0.31, 0.40, 0.39, 0.48% and 3.28, 3.48, 4.16, 3.42% for senkirkine, senecionine, retrorsine, and seneciphylline, respectively. Limits of detection (S/N = 3) varied from 1.19 to 2.70 microg/mL. The proposed method was applied to determine the PAs extracted from Chinese herbal medicines (Qian liguang and Kuan donghua). PA of senkirkine in Kuan donghua was detected and the amount was found to be 79.1 microg/g. The results obtained indicate that the proposed MEKC method could potentially become an effective alternative tool for qualification control and quantitative analysis of herbal medicines in pharmaceutical industry. PMID:16080213

Yu, Lijun; Xu, Yan; Feng, Huatao; Li, Sam Fong Yau

2005-09-01

418

Evaluation of the enantioseparation capability of the novel chiral selector clindamycin phosphate towards basic drugs by micellar electrokinetic chromatography.  

PubMed

To date, a series of chiral selectors have been utilized successfully in capillary electrophoresis (CE). Among these various chiral selectors, macrocyclic antibiotics have been demonstrated to represent powerful enantioselectivity towards many chiral compounds. Differing from macrocyclic antibiotics, the use of lincosamide antibiotics as chiral selectors has not been reported previously. In our recent work, clindamycin phosphate belonging to the group of lincosamides has been first used as a chiral selector in capillary zone electrophoresis (CZE). In this paper, a micellar electrokinetic chromatography (MEKC) method has been developed for the evaluation of enantioseparation capability of this novel chiral selector towards several racemic basic drugs. As observed during the course of this work, clindamycin phosphate allowed excellent separation of the enantiomers of nefopam, citalopram, tryptophan, chlorphenamine, propranolol and metoprolol, as well as partial enantioresolution of tryptophan methyl ester and cetirizine. In this MEKC chiral separation system, different types of anionic surfactants, organic additives and background electrolytes were tested, and satisfactory enantioseparations of basic drugs above-mentioned were achieved using sodium dodecyl sulfate (SDS) as the surfactant, isopropanol as the organic additive, and phosphate as the background electrolyte. Furthermore, both migration times and enantioseparation of the analytes were influenced by several experimental parameters such as pH of the BGE, clindamycin phosphate and SDS concentrations, phosphate and isopropanol concentrations, and applied voltage. Consequently, the effects of these factors on enantioseparations of the studied basic drugs were systematically investigated in order to evaluate the stereoselectivity of clindamycin phosphate in MEKC. PMID:20132938

Chen, Bin; Du, Yingxiang

2010-03-12

419

Determination of nitrogen fixation effectiveness in selected Medicago truncatula isolates by measuring nitrogen isotope incorporation into pheophytin  

Microsoft Academic Search

Effectiveness is a term used to describe the input that a bacterial nitrogen-fixing symbiosis makes to plant nitrogen metabolism. In legumes, effectiveness is considered a polymorphic trait where specific interactions between the plant and symbiotic rhizobia contribute to the success of the interaction. Evaluation of effectiveness using model legumes like Medicago truncatula may open new avenues for genetic studies. In

Adriana Parra-Colmenares; Michael L. Kahn

2005-01-01

420

Incorporation of network in synthesis of zircon-imprinted polymer and its effect on zircon ion extraction  

NASA Astrophysics Data System (ADS)

The material polymer functionalized on SPE have been developed by ion- imprinted polymer. The ion-polymer with zircon ion as imprint ions were synthesized via bulk polymerization methods by forming binary complex Zr-Xylenol orange in 2-methoxy ethanol and copolymerizing in the presence of styrene as a monomer functional, divinyl benzene as a monomer cross-linker, and peroxide as an initiator. The zircon-imprinted polymer produced the porous polymer. It was indicated that zircon ion imprints were released under conditioning. The polymer particles both prior to and after leaching have been characterized by IR, SEM-EDS, TEM, and pore size. Incorporation of network polymer using divinyl benzene as the cross-linker were performances tested on zircon ion extraction, and the optimum of the mole ratio of styrene/DVB was observed about 1. The decrease of percent extraction of zircon ion when the mole ration of styrene/divinyl benzene < 1, due to the pores as binding sites of polymers were covered, and it was evidenced by the decrease in total pore volume.

Aladin, S.; Amran, M. B.; Buchari, B.; Arcana, I. M.

2014-03-01

421

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

E-print Network

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 ~40{\\deg}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 usin...

van Hulten, Marco; Middag, Rob; de Baar, Hein; Gehlen, Marion; Dutay, Jean-Claude; Tagliabue, Alessandro

2014-01-01

422

Palmitoylation of the feline immunodeficiency virus envelope glycoprotein and its effect on fusion activity and envelope incorporation into virions  

SciTech Connect

The feline immunodeficiency virus (FIV) envelope glycoprotein (Env) possesses a short cytoplasmic domain of 53 amino acids containing four highly conserved cysteines at Env positions 804, 811, 815 and 848. Since palmitoylation of transmembrane proteins occurs at or near the membrane anchor, we investigated whether cysteines 804, 811 and 815 are acylated and analyzed the relevance of these residues for Env functions. Replacement of cysteines 804, 811 and 815 individually or in combination by serine residues resulted in Env glycoproteins that were efficiently expressed and processed. However, mutations C804S and C811S reduced Env fusogenicity by 93% and 84%, respectively, compared with wild-type Env. By contrast, mutant C815S exhibited a fusogenic capacity representing 50% of the wild-type value. Remarkably, the double mutation C804S/C811S abrogated both Env fusion activity and Env incorporation into virions. Finally, by means of Click chemistry assays we demonstrated that the four FIV Env cytoplasmic cysteines are palmitoylated.

Gonzalez, Silvia A.; Paladino, Monica G. [Laboratorio de Virologia, CONICET-Universidad de Belgrano (UB), Villanueva 1324 (C1426BMJ), Buenos Aires (Argentina)] [Laboratorio de Virologia, CONICET-Universidad de Belgrano (UB), Villanueva 1324 (C1426BMJ), Buenos Aires (Argentina); Affranchino, Jose L., E-mail: jose.affranchino@comunidad.ub.edu.ar [Laboratorio de Virologia, CONICET-Universidad de Belgrano (UB), Villanueva 1324 (C1426BMJ), Buenos Aires (Argentina)

2012-06-20

423

Effect of beta-decay of radionuclides incorporated into influenza virus RNA and proteins on the infectivity of the virus and antigenicity of its nucleoprotein.  

PubMed

The effect of beta-decay of radionuclides incorporated into influenza virus on the properties of the two closely adjacent structures--RNA and nucleoprotein (NP)--was studied. The long-term storage of 3H-uridine labelled influenza virus was shown to lead to the loss of infectivity. This effect may be explained by lethal intra-molecular modifications of viral RNA, caused by beta-decay of 3H incorporated into the molecule. There was an accompanying decrease of monoclonal antibody (MAB) binding activity, this also being a plausible result of beta-decay. The different rates of inactivation of MAB binding activity of different epitopes of NP of the 3H-labelled virus shown in our studies suggest that there are different types of structural organization or different location of these epitopes in the NP. The effect of 3H-decay on the intracellular RNA of reproducing virus lead to a decrease in virus yield; this may be due to radiation- and transmutation-induced damage of messenger and progeny RNA populations synthesized during the infection. The storage of influenza virus labelled with 14C-aminoacids lead to a decrease in MAB binding activity of the NP that was unaccompanied by a decrease in infectivity. Furthermore, 14C-decay in proteins of reproducing virus had no adverse effect. PMID:3426399

Prokudina, E N; Semyonova, N P; Yamnikova, S S; Zhdanov, V M

1987-01-01

424

Simultaneous determination of gaseous and particulate carbonyls in air by coupling micellar electrokinetic capillary chromatography with molecular imprinting solid-phase extraction.  

PubMed

A novel method coupling molecular imprinting solid-phase extraction (MISPE) and micellar electrokinetic capillary chromatography (MEKC) was developed to enable the hourly determination of low level of ambient carbonyls, and study their partition between gaseous phase and particulate phase. With 2,4-dinitroaniline (DNAN) as dummy imprinting template, the unreacted 2,4-Dinitrophenylhydrazine (DNPH) in sampling solution could be removed effectively using MISPE, and an average recovery of 97±5.3% (n=5) for the carbonyl-DNPH derivatives was achieved. Owing to the high enrichment due to sample clean-up, and the improvement of MEKC separation efficiency, many low abundant carbonyls could be detected by hourly in the field study. PMID:25069741

Sun, Hui; Lai, Jia-Ping; Fung, Ying Sing

2014-09-01

425

Effects of methylprednisolone on concanavalin A-induced human lymphocyte blastogenesis: a comparative analysis by flow cytometry, volume determination and /sup 3/H-thymidine incorporation  

SciTech Connect

The inhibition of concanavalin A-induced human peripheral blood lymphocyte blastogenesis by methylprednisolone (MP) was studied by using flow cytometry and tritiated thymidine (/sup 3/H-TdR) incorporation. Flow cytometric determinations of volume, low angle forward light scatter, and nucleic acid showed MP to be a potent inhibitor of blastogenesis. The effects were concentration-dependent and correlated with /sup 3/H-TdR uptake. By using the single cell analytic capability of flow cytometry, the target stages of the cell cycle where MP affects lymphocyte activation were determined. Evidence is presented that steroids can block both early and late phases of this process.

Marder, P.; Schmidtke, J.R.

1983-08-01

426

Mobilization of phenol and dichlorophenol in unsaturated soils by non-uniform electrokinetics.  

PubMed

The poor mobility of organic pollutants in contaminated sites frequently results in slow remediation processes. Organics, especially hydrophobic compounds, are generally retained strongly in soil matrix as a result of sorption, sequestration, or even formation into non-aqueous-phase liquids and their mobility is thus greatly reduced. The objective of this study was to evaluate the feasibility of using non-uniform electrokinetic transport processes to enhance the mobility of organic pollutants in unsaturated soils with no injection reagents. Phenol and 2,4-dichlorophenol (2,4-DCP), and kaolin and a natural sandy loam soil were selected as model organics and soils, respectively. The results showed that non-uniform electrokinetics can accelerate the desorption and movement of phenol and 2,4-DCP in unsaturated soils. Electromigration and electroosmotic flow were the main driving forces, and their role in the mobilization of phenol and 2,4-DCP varied with soil pH. The movement of 2,4-DCP in the sandy loam towards the anode (about 1.0 cmd(-1)V(-1)) was 1.0-1.5 cmd(-1)V(-1) slower than that in the kaolin soil, but about 0.5 cmd(-1)V(-1) greater than that of phenol in the sandy loam. When the sandy loam was adjusted to pH 9.3, the movement of phenol and 2,4-DCP towards the anode was about twice and five times faster than that at pH 7.7, respectively. The results also demonstrated that the movement of phenol and 2,4-DCP in soils can be easily controlled by regulating the operational mode of electric field. It is believed that non-uniform electrokinetics has the potential for practical application to in situ remediation of organics-contaminated sites. PMID:15857640

Luo, Qishi; Zhang, Xihui; Wang, Hui; Qian, Yi

2005-06-