21 CFR 882.1540 - Galvanic skin response measurement device.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Galvanic skin response measurement device. 882... Galvanic skin response measurement device. (a) Identification. A galvanic skin response measurement device... electrical resistance of the skin and the tissue path between two electrodes applied to the skin. (b...

21 CFR 882.1540 - Galvanic skin response measurement device.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Galvanic skin response measurement device. 882... Galvanic skin response measurement device. (a) Identification. A galvanic skin response measurement device... electrical resistance of the skin and the tissue path between two electrodes applied to the skin. (b...

21 CFR 882.1540 - Galvanic skin response measurement device.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Galvanic skin response measurement device. 882... Galvanic skin response measurement device. (a) Identification. A galvanic skin response measurement device... electrical resistance of the skin and the tissue path between two electrodes applied to the skin. (b...

21 CFR 882.1540 - Galvanic skin response measurement device.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Galvanic skin response measurement device. 882... Galvanic skin response measurement device. (a) Identification. A galvanic skin response measurement device... electrical resistance of the skin and the tissue path between two electrodes applied to the skin. (b...

Simulation on the steel galvanic corrosion and acoustic emission

NASA Astrophysics Data System (ADS)

Yu, Yang; Shi, Xin; Yang, Ping

2015-12-01

Galvanic corrosion is a very destructive localized corrosion. The research on galvanic corrosion could determine equipment corrosion and prevent the accidents occurrence. Steel corrosion had been studied by COMSOL software with mathematical modeling. The galvanic corrosion of steel-aluminum submerged into 10% sodium chloride solution had been on-line detected by PIC-2 acoustic emission system. The results show that the acoustic emission event counts detected within unit time can qualitative judge galvanic corrosion rate and further erosion trend can be judged by the value changes.

The effect of cell density, proximity, and time on the cytotoxicity of magnesium and galvanically coupled magnesium-titanium particles in vitro.

PubMed

Kim, Jua; Gilbert, Jeremy L

2018-05-01

Magnesium (Mg) and galvanically coupled magnesium-titanium (Mg-Ti) particles in vitro have been reported previously to kill cells in a dosage-dependent manner. Mg-Ti particles kill cells more effectively than Mg alone, due to the galvanic effect of Mg and Ti. This study further investigated the in vitro cytotoxicity of Mg and Mg-Ti in terms of particle concentration, cell density, time, and proximity. Cell density has an effect on cell viability only at low particle concentrations (below 250 µg/mL), where cell viability dropped only for lower cell densities (5000-10,000 cells/cm 2 ) and not for higher cell densities (20,000-30,000 cells/cm 2 ), showing that the particles cannot kill if there are more cells present. Cytotoxicity of Mg and Mg-Ti particles is quick and temporary, where the particles kill cells only during particle corrosion (first 24 h). Depending on the percentage of surviving cells, particle concentrations, and ongoing corrosion activity, the remaining live cells either proliferated and recovered, or just remained viable and quiescent. The particle killing is also proximity-dependent, where cell viability was significantly higher for cells far away from the particles (greater than ∼1 mm) compared to those close to the particles (less than ∼1 mm). Although the increase of pH does affect cell viability negatively, it is not the sole killing factor since cell viability is significantly dependent on particle type and proximity but not pH. Mg and Mg-Ti particles used in this study are large enough to prevent direct cell phagocytosis so that the cell killing effect may be attributed to solely electrochemical reactions. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1428-1439, 2018. © 2018 Wiley Periodicals, Inc.

77 FR 28404 - Galvanized Steel Wire From China and Mexico

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-14

...)] Galvanized Steel Wire From China and Mexico Determinations On the basis of the record \\1\\ developed in the... reason of imports from China of galvanized steel wire, provided for in subheadings 7217.20.30, 7217.20.45... reason of imports from Mexico of galvanized steel wire, provided for in subheadings 7217.20.30, 7217.20...

Galvanic Cell Type Sensor for Soil Moisture Analysis.

PubMed

Gaikwad, Pramod; Devendrachari, Mruthyunjayachari Chattanahalli; Thimmappa, Ravikumar; Paswan, Bhuneshwar; Raja Kottaichamy, Alagar; Makri Nimbegondi Kotresh, Harish; Thotiyl, Musthafa Ottakam

2015-07-21

Here we report the first potentiometric sensor for soil moisture analysis by bringing in the concept of Galvanic cells wherein the redox energies of Al and conducting polyaniline are exploited to design a battery type sensor. The sensor consists of only simple architectural components, and as such they are inexpensive and lightweight, making it suitable for on-site analysis. The sensing mechanism is proved to be identical to a battery type discharge reaction wherein polyaniline redox energy changes from the conducting to the nonconducting state with a resulting voltage shift in the presence of soil moisture. Unlike the state of the art soil moisture sensors, a signal derived from the proposed moisture sensor is probe size independent, as it is potentiometric in nature and, hence, can be fabricated in any shape or size and can provide a consistent output signal under the strong aberration conditions often encountered in soil moisture analysis. The sensor is regenerable by treating with 1 M HCl and can be used for multiple analysis with little read out hysteresis. Further, a portable sensor is fabricated which can provide warning signals to the end user when the moisture levels in the soil go below critically low levels, thereby functioning as a smart device. As the sensor is inexpensive, portable, and potentiometric, it opens up avenues for developing effective and energy efficient irrigation strategies, understanding the heat and water transfer at the atmosphere-land interface, understanding soil mechanics, forecasting the risk of natural calamities, and so on.

40 CFR 465.20 - Applicability; description of the galvanized basis material subcategory.

Code of Federal Regulations, 2010 CFR

2010-07-01

... galvanized basis material subcategory. 465.20 Section 465.20 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS COIL COATING POINT SOURCE CATEGORY Galvanized Basis Material Subcategory § 465.20 Applicability; description of the galvanized basis material...

Galvanic Corrosion Behavior of Microwave Welded and Post-weld Heat-Treated Inconel-718 Joints

NASA Astrophysics Data System (ADS)

Bansal, Amit; Sharma, Apurbba Kumar; Kumar, Pradeep

2017-05-01

In the present study, corrosion behavior of microwave welded Inconel-718 at various conditions was investigated. Welding of Inconel-718 in 980 °C solution-treated condition was performed using microwave hybrid heating technique. The microwave welds were subjected to post-heat treatment for improving its microstructure and mechanical properties by solubilizing the Nb-enriched Laves phase. The microstructural features of the fabricated welds at various conditions were investigated through scanning electron microscopy. The electrochemical testing results revealed that Inconel-718 welds were galvanic corroded when they were anodically polarized in 3.5 wt.% NaCl solution at 28 °C. The difference in the corrosion potentials between the base metal (BM) and fusion zone (FZ) in an Inconel-718 weld was the main factor for galvanic corrosion. The highest corrosion was occurred in the as-welded/aged weldments, followed by 980 °C solution-treated and aged weldments, as-welded specimen, and 1080 °C solution-treated and aged (1080STA) weldments. The least galvanic corrosion was occurred in the 1080STA specimens due to almost uniform microstructure developed in the weldment after the treatment. Thus, it was possible to minimize the galvanic corrosion in the microwave welded Inconel-718 by 1080STA treatment which resulted in reducing the difference in corrosion potentials between the BM and the FZ.

Measurement of adhesion properties between topcoat paint and metallized/galvanized steel with surface energy measurement equipment.

DOT National Transportation Integrated Search

2013-09-01

The objectives of this research project are: (1) Compare the adhesion properties of NEPCOAT-approved topcoat paint over : metallized or galvanized steel. Use surface-energy measuring technique to characterize the wetting properties of the liqui...

A Galvanic Sensor for Monitoring the Corrosion Condition of the Concrete Reinforcing Steel: Relationship Between the Galvanic and the Corrosion Currents

PubMed Central

Pereira, Elsa Vaz; Figueira, Rita Bacelar; Salta, Maria Manuela Lemos; da Fonseca, Inês Teodora Elias

2009-01-01

This work reports a study carried out on the design and performance of galvanic and polarization resistance sensors to be embedded in concrete systems for permanent monitoring of the corrosion condition of reinforcing steel, aiming to establish a correlation between the galvanic currents, Igal, and the corrosion currents, Icorr, estimated from the polarization resistance, Rp. Sensors have been tested in saturated Ca(OH)2 aqueous solutions, under a variety of conditions, simulating the most important parameters that can accelerate the corrosion of concrete reinforcing steel, such as carbonation, ingress of chloride ions, presence or absence of O2. For all the conditions, the influence of temperature (20 to 55 °C) has also been considered. From this study, it could be concluded that the galvanic currents are sensitive to the various parameters following a trend similar to that of the Rp values. A relationship between the galvanic and the corrosion current densities was obtained and the limiting values of the Igal, indicative of the state condition of the reinforcing steel for the designed sensor, were established. PMID:22291514

Galvanic Manufacturing in the Cities of Russia: Potential Source of Ambient Nanoparticles

PubMed Central

Golokhvast, Kirill S.; Shvedova, Anna A.

2014-01-01

Galvanic manufacturing is widely employed and can be found in nearly every average city in Russia. The release and accumulation of different metals (Me), depending on the technology used can be found in the vicinities of galvanic plants. Under the environmental protection act in Russia, the regulations for galvanic manufacturing do not include the regulations and safety standards for ambient ultrafine and nanosized particulate matter (PM). To assess whether Me nanoparticles (NP) are among environmental pollutants caused by galvanic manufacturing, the level of Me NP were tested in urban snow samples collected around galvanic enterprises in two cities. Employing transmission electronic microscopy, energy-dispersive X-ray spectroscopy, and a laser diffraction particle size analyzer, we found that the size distribution of tested Me NP was within 10–120 nm range. This is the first study to report that Me NP of Fe, Cr, Pb, Al, Ni, Cu, and Zn were detected around galvanic shop settings. PMID:25329582

Simulation to coating weight control for galvanizing

NASA Astrophysics Data System (ADS)

Wang, Junsheng; Yan, Zhang; Wu, Kunkui; Song, Lei

2013-05-01

Zinc coating weight control is one of the most critical issues for continuous galvanizing line. The process has the characteristic of variable-time large time delay, nonlinear, multivariable. It can result in seriously coating weight error and non-uniform coating. We develop a control system, which can automatically control the air knives pressure and its position to give a constant and uniform zinc coating, in accordance with customer-order specification through an auto-adaptive empirical model-based feed forward adaptive controller, and two model-free adaptive feedback controllers . The proposed models with controller were applied to continuous galvanizing line (CGL) at Angang Steel Works. By the production results, the precise and stability of the control model reduces over-coating weight and improves coating uniform. The product for this hot dip galvanizing line does not only satisfy the customers' quality requirement but also save the zinc consumption.

7 CFR 1755.370 - RUS specification for seven wire galvanized steel strand.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 11 2011-01-01 2011-01-01 false RUS specification for seven wire galvanized steel..., ACCEPTABLE MATERIALS, AND STANDARD CONTRACT FORMS § 1755.370 RUS specification for seven wire galvanized... Steel Wire Strand, issued May 1978. All seven wire galvanized steel strand purchased after April 1, 1990...

7 CFR 1755.370 - RUS specification for seven wire galvanized steel strand.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 11 2010-01-01 2010-01-01 false RUS specification for seven wire galvanized steel..., ACCEPTABLE MATERIALS, AND STANDARD CONTRACT FORMS § 1755.370 RUS specification for seven wire galvanized... Steel Wire Strand, issued May 1978. All seven wire galvanized steel strand purchased after April 1, 1990...

Polyfibroblast: A Self-Healing and Galvanic Protection Additive

DTIC Science & Technology

2012-09-12

self-healing and galvanic protection capacity to the primer (Figure 1). Polyfibroblast consists of paint-filled microcapsules and zinc powder. It has...significant added cost. Microcapsule Figure 1. Polyfibroblast contains fresh paint encapsulated in polymer shells plus Zn powder. When scratched, resin...from the broken microcapsules fills the crack to form a polymer scar. Zn powder supplies galvanic protection in the event of incomplete healing

Grade 12 Students' Conceptual Understanding and Mental Models of Galvanic Cells before and after Learning by Using Small-Scale Experiments in Conjunction with a Model Kit

ERIC Educational Resources Information Center

Supasorn, Saksri

2015-01-01

This study aimed to develop the small-scale experiments involving electrochemistry and the galvanic cell model kit featuring the sub-microscopic level. The small-scale experiments in conjunction with the model kit were implemented based on the 5E inquiry learning approach to enhance students' conceptual understanding of electrochemistry. The…

Mineralogical Evidence of Galvanic Corrosion in Domestic, Drinking Water Pipes

EPA Science Inventory

Drinking water distribution system (DWDS) piping contains numerous examples of galvanically-coupled metals (e.g., soldered copper pipe joints, copper-lead pipes joined during partial replacements of lead service lines). The possible role of galvanic corrosion in the release of l...

Alexander von Humboldt: galvanism, animal electricity, and self-experimentation part 1: formative years, naturphilosophie, and galvanism.

PubMed

Finger, Stanley; Piccolino, Marco; Stahnisch, Frank W

2013-01-01

During the 1790s, Alexander von Humboldt (1769-1859), who showed an early interest in many facets of natural philosophy and natural history, delved into the controversial subject of galvanism and animal electricity, hoping to shed light on the basic nature of the nerve force. He was motivated by his broad worldview, the experiments of Luigi Galvani, who favored animal electricity in more than a few specialized fishes, and the thinking of Alessandro Volta, who accepted specialized fish electricity but was not willing to generalize to other animals, thinking Galvani's frog experiments flawed by his use of metals. Differing from many German Naturphilosophen, who shunned "violent" experiments, the newest instruments, and detailed measurement, Humboldt conducted thousands of galvanic experiments on animals and animal parts, as well as many on his own body, some of which caused him great pain. He interpreted his results as supporting some but not all of the claims made by both Galvani and Volta. Notably, because of certain negative findings and phenomenological differences, he remained skeptical about the intrinsic animal force being qualitatively identical to true electricity. Hence, he referred to a "galvanic force," not animal electricity, in his letters and publications, a theoretical position he would abandon with Volta's help early in the new century.

76 FR 55031 - Galvanized Steel Wire From the People's Republic of China: Preliminary Affirmative Countervailing...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-06

... DEPARTMENT OF COMMERCE International Trade Administration [C-570-976] Galvanized Steel Wire From... galvanized steel wire (galvanized wire) from the People's Republic of China (PRC). For information on the..., filed in proper form, concerning imports of galvanized wire from the PRC.\\1\\ The Department initiated a...

Effect of Immersion Time and Cooling Mode on the Electrochemical Behavior of Hot-Dip Galvanized Steel in Sulfuric Acid Medium

NASA Astrophysics Data System (ADS)

Lekbir, Choukri; Dahoun, Nessrine; Guetitech, Asma; Hacid, Abdenour; Ziouche, Aicha; Ouaad, Kamel; Djadoun, Amar

2017-04-01

In this work, we investigated the influence of galvanizing immersion time and cooling modes environments on the electrochemical corrosion behavior of hot-dip galvanized steel, in 1 M sulfuric acid electrolyte at room temperature using potentiodynamic polarization technique. In addition, the evolution of thickness, structure and microstructure of zinc coatings for different immersion times and two cooling modes (air and water) is characterized, respectively, by using of Elcometer scan probe, x-ray diffraction and metallography analysis. The analysis of the behavior of steel and galvanized steel, vis-a-vis corrosion, by means of corrosion characteristic parameters as anodic (β a) and cathodic (β c) Tafel slopes, corrosion potential (E corr), corrosion current density (i corr), corrosion rate (CR) and polarization resistance (R p), reveals that the galvanized steel has anticorrosion properties much better than that of steel. More the immersion time increases, more the zinc coatings thickness increases, and more these properties become better. The comparison between the two cooling modes shows that the coatings of zinc produced by hot-dip galvanization and air-cooled provides a much better protection to steel against corrosion than those cooled by quenching in water which exhibit a brittle corrosive behavior due to the presence of cracks.

Performance of Inductors Attached to a Galvanizing Bath

NASA Astrophysics Data System (ADS)

Zhou, Xinping; Yuan, Shuo; Liu, Chi; Yang, Peng; Qian, Chaoqun; Song, Bao

2013-12-01

By taking a galvanizing bath with inductors from an Iron and Steel Co., Ltd as an example, the distributions of Lorentz force and generated heat in the inductor are simulated. As a result, the zinc flow and the temperature distribution driven by the Lorentz force and the generated heat in the inductor of a galvanizing bath are simulated numerically, and their characteristics are analyzed. The relationship of the surface-weighted average velocity at the outlet and the temperature difference between the inlet and the outlet and the effective power for the inductor is studied. Results show that with an increase in effective power for the inductor, the surface-weighted average velocity at the outlet and the temperature difference between the inlet and the outlet increase gradually. We envisage this work to lay a foundation for the study of the performance of the galvanizing bath in future.

Corrosion of galvanized transmission towers near the Colbert Steam Plant: data report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Coleman, J.H.

1980-01-01

This report contains data relating power plant emissions and the thickness of the galvanized layers on 20 electric transmission towers near the Colbert Steam plant after 25 years of ambient exposure. In addition to the thickness of the galvanized layers, total exposure to SO/sub 2/ at each tower was estimated and relevant meteorological data were reported. These data may be useful in relating galvanized corrosion to power plant emissions.

Galvanic corrosion of nitinol under deaerated and aerated conditions.

PubMed

Pound, Bruce G

2016-10-01

Various studies have examined the corrosion rate of nitinol generally under deaerated conditions. Likewise, galvanic corrosion studies have typically involved deaerated solutions. This work addressed the effect of galvanic coupling on the corrosion current of electropolished nitinol in phosphate buffered saline and 0.9% sodium chloride under dearated and aerated conditions for times up to 24 h. Tests were performed on nitinol alone and coupled with MP35N in both the mechanically polished and passivated conditions. Aeration and galvanic coupling were found to have relatively little effect, indicating that the corrosion current is controlled by the anodic reaction. The current can be attributed entirely to Ni(2+) dissolution, which appears to be governed by solid-state mass transport of Ni(2+) through the passive oxide film. Because corrosion of EP nitinol is controlled by the anodic reaction, contact between EP nitinol and MP35N or other biomedical Co-Cr alloys is unlikely to result in significant galvanic effects in vivo. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1322-1327, 2016. © 2015 Wiley Periodicals, Inc.

Effect of hot-dip galvanizing processes on the microstructure and mechanical properties of 600-MPa hot-dip galvanized dual-phase steel

NASA Astrophysics Data System (ADS)

Kuang, Chun-fu; Zheng, Zhi-wang; Wang, Min-li; Xu, Quan; Zhang, Shen-gen

2017-12-01

A C-Mn dual-phase steel was soaked at 800°C for 90 s and then either rapidly cooled to 450°C and held for 30 s (process A) or rapidly cooled to 350°C and then reheated to 450°C (process B) to simulate the hot-dip galvanizing process. The influence of the hot-dip galvanizing process on the microstructure and mechanical properties of 600-MPa hot-dip galvanized dual-phase steel (DP600) was investigated using optical microscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and tensile tests. The results showed that, in the case of process A, the microstructure of DP600 was composed of ferrite, martensite, and a small amount of bainite. The granular bainite was formed in the hot-dip galvanizing stage, and martensite islands were formed in the final cooling stage after hot-dip galvanizing. By contrast, in the case of process B, the microstructure of the DP600 was composed of ferrite, martensite, bainite, and cementite. In addition, compared with the yield strength (YS) of the DP600 annealed by process A, that for the DP600 annealed by process B increased by approximately 50 MPa because of the tempering of the martensite formed during rapid cooling. The work-hardening coefficient ( n value) of the DP600 steel annealed by process B clearly decreased because the increase of the YS affected the computation result for the n value. However, the ultimate tensile strength (UTS) and elongation ( A 80) of the DP600 annealed by process B exhibited less variation compared with those of the DP600 annealed by process A. Therefore, DP600 with excellent comprehensive mechanical properties (YS = 362 MPa, UTS = 638 MPa, A 80 = 24.3%, n = 0.17) was obtained via process A.

The timing of galvanic vestibular stimulation affects responses to platform translation

NASA Technical Reports Server (NTRS)

Hlavacka, F.; Shupert, C. L.; Horak, F. B.; Peterson, B. W. (Principal Investigator)

1999-01-01

We compared the effects of galvanic vestibular stimulation applied at 0, 0.5, 1.5 and 2.5 s prior to a backward platform translation on postural responses. The effect of the galvanic stimulation was largest on the final equilibrium position of the center of pressure (CoP). The largest effects occurred for the 0.5 and 0-s pre-period, when the dynamic CoP pressure changes in response to both the galvanic stimulus and the platform translation coincided. The shift in the final equilibrium position was also larger than the sum of the shifts for the galvanic stimulus and the platform translation alone for the 0.5 and 0-s pre-periods. The initial rate of change of the CoP response to the platform translation was not significantly affected in any condition. Changes in the peak CoP position could be accounted for by local interaction of CoP velocity changes induced by the galvanic and translation responses alone, but the changes in final equilibrium position could only be accounted for by a change in global body orientation. These findings suggest that the contribution of vestibulospinal information is greatest during the dynamic phase of the postural response, and that the vestibular system contributes most to the later components of the postural response, particularly to the final equilibrium position. These findings suggest that a nonlinear interaction between the vestibular signal induced by the galvanic current and the sensory stimuli produced by the platform translation occurs when the two stimuli are presented within 1 s, during the dynamic phase of the postural response to the galvanic stimulus. When presented at greater separations in time, the stimuli appear to be treated as independent events, such that no interaction occurs. Copyright 1999 Elsevier Science B.V.

76 FR 19382 - Galvanized Steel Wire From China and Mexico

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-07

...)] Galvanized Steel Wire From China and Mexico AGENCY: United States International Trade Commission. ACTION... galvanized steel wire, provided for in subheading 7217.20.30 and 7217.20.45 of the Harmonized Tariff Schedule... investigations are being instituted in response to a petition filed on March 31, 2011, by Davis Wire Corp...

76 FR 29266 - Galvanized Steel Wire From China and Mexico

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-20

...)] Galvanized Steel Wire From China and Mexico Determinations On the basis of the record \\1\\ developed in the... reason of imports from China and Mexico of galvanized steel wire, provided for in subheading 7217.20.30... March 31, 2011, a petition was filed with the Commission and Commerce by Davis Wire Corporation...

76 FR 68422 - Galvanized Steel Wire From Mexico: Preliminary Determination of Sales at Less Than Fair Value and...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-04

... DEPARTMENT OF COMMERCE International Trade Administration [A-201-840] Galvanized Steel Wire From... determines that galvanized steel wire (galvanized wire) from Mexico is being, or is likely to be, sold in the... investigation on galvanized wire from Mexico. See Galvanized Steel Wire from the People's Republic of China and...

76 FR 33242 - Galvanized Steel Wire From the People's Republic of China: Postponement of Preliminary...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-08

... DEPARTMENT OF COMMERCE International Trade Administration [C-570-976] Galvanized Steel Wire From... the countervailing duty investigation of galvanized steel wire from the People's Republic of China. See Galvanized Steel Wire From the People's Republic of China: Initiation of Countervailing Duty...

Coating Galvanized Steel

DTIC Science & Technology

1989-06-01

bonding of topcoats to smooth galvanizing have lead to such practices as washing with vinegar , washing with copper sulfate solution, or weathering before...of special treatments other than weathering: "The "home cure" type of treatments such as washing the surface with vinegar , acetic acid, cider, copper... alcohol . The wash primer used was MIL-P-15328 (Formula 117). It is spray- applied to give 0.3- to 0.5-mil dry film thickness and is used on ships to

Fiber laser welding of dual-phase galvanized sheet steel (DP590): traditional analysis and new quality assessment techniques

NASA Astrophysics Data System (ADS)

Miller, Stephanie; Pfeif, Erik; Kazakov, Andrei; Baumann, Esther; Dowell, Marla

2016-03-01

Laser welding has many advantages over traditional joining methods, yet remains underutilized. NIST has undertaken an ambitious initiative to improve predictions of weldability, reliability, and performance of laser welds. This study investigates butt welding of galvanized and ungalvanized dual-phase automotive sheet steels (DP 590) using a 10 kW commercial fiber laser system. Parameter development work, hardness profiles, microstructural characterization, and optical profilometry results are presented. Sound welding was accomplished in a laser power range of 2.0 kW to 4.5 kW and travel speed of 2000 mm/min to 5000 mm/min. Vickers hardness ranged from approximately 2 GPa to 4 GPa across the welds, with limited evidence of heat affected zone softening. Decreased hardness across the heat affected zone directly correlated to the appearance of ferrite. A technique was developed to non-destructively evaluate weld quality based on geometrical criteria. Weld face profilometry data were compared between light optical, metallographic sample, and frequency-modulated continuous-wave laser detection and ranging (FMCW LADAR) methods.

Anticorrosive Behavior and Porosity of Tricationic Phosphate and Zirconium Conversion Coating on Galvanized Steel

NASA Astrophysics Data System (ADS)

Velasquez, Camilo S.; Pimenta, Egnalda P. S.; Lins, Vanessa F. C.

2018-05-01

This work evaluates the corrosion resistance of galvanized steel treated with tricationic phosphate and zirconium conversion coating after painting, by using electrochemical techniques, accelerated and field corrosion tests. A non-uniform and heterogeneous distribution of zirconium on the steel surface was observed due to preferential nucleation of the zirconium on the aluminum-rich sites on the surface of galvanized steel. The long-term anti-corrosion performance in a saline solution was better for the phosphate coating up to 120 days. The coating capacitance registered a higher increase for the zirconium coatings than the phosphate coatings up to 120 days of immersion. This result agrees with the higher porosity of zirconium coating in relation to the phosphate coating. After 3840 h of accelerated corrosion test, and after 1 year of accelerated field test, zirconium-treated samples showed an average scribe delamination length higher than the phosphate-treated samples.

Anticorrosive Behavior and Porosity of Tricationic Phosphate and Zirconium Conversion Coating on Galvanized Steel

NASA Astrophysics Data System (ADS)

Velasquez, Camilo S.; Pimenta, Egnalda P. S.; Lins, Vanessa F. C.

2018-04-01

This work evaluates the corrosion resistance of galvanized steel treated with tricationic phosphate and zirconium conversion coating after painting, by using electrochemical techniques, accelerated and field corrosion tests. A non-uniform and heterogeneous distribution of zirconium on the steel surface was observed due to preferential nucleation of the zirconium on the aluminum-rich sites on the surface of galvanized steel. The long-term anti-corrosion performance in a saline solution was better for the phosphate coating up to 120 days. The coating capacitance registered a higher increase for the zirconium coatings than the phosphate coatings up to 120 days of immersion. This result agrees with the higher porosity of zirconium coating in relation to the phosphate coating. After 3840 h of accelerated corrosion test, and after 1 year of accelerated field test, zirconium-treated samples showed an average scribe delamination length higher than the phosphate-treated samples.

77 FR 17418 - Galvanized Steel Wire From the People's Republic of China: Final Affirmative Countervailing Duty...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-26

... DEPARTMENT OF COMMERCE International Trade Administration [C-570-976] Galvanized Steel Wire From... exporters of galvanized steel wire (galvanized wire) from the People's Republic of China (the PRC). For... investigation are Davis Wire Corporation, Johnstown Wire Technologies, Inc., Mid- South Wire Company, Inc...

76 FR 73589 - Galvanized Steel Wire From the People's Republic of China: Amended Preliminary Determination of...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-29

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-975] Galvanized Steel Wire From... galvanized steel wire from the People's Republic of China (``PRC'').\\1\\ We are amending our Preliminary... Fair Value and Postponement of Final Determination: Galvanized Steel Wire from the People's Republic of...

Galvanic Corrosion of Lead by Iron (Oxyhydr)Oxides: Potential Impacts on Drinking Water Quality.

PubMed

Trueman, Benjamin F; Sweet, Gregory A; Harding, Matthew D; Estabrook, Hayden; Bishop, D Paul; Gagnon, Graham A

2017-06-20

Lead exposure via drinking water remains a significant public health risk; this study explored the potential effects of upstream iron corrosion on lead mobility in water distribution systems. Specifically, galvanic corrosion of lead by iron (oxyhydr)oxides was investigated. Coupling an iron mineral cathode with metallic lead in a galvanic cell increased lead release by 531 μg L -1 on average-a 9-fold increase over uniform corrosion in the absence of iron. Cathodes were composed of spark plasma sintered Fe 3 O 4 or α-Fe 2 O 3 or field-extracted Fe 3 O 4 and α-FeOOH. Orthophosphate immobilized oxidized lead as insoluble hydroxypyromorphite, while humic acid enhanced lead mobility. Addition of a humic isolate increased lead release due to uniform corrosion by 81 μg L -1 and-upon coupling lead to a mineral cathode-release due to galvanic corrosion by 990 μg L -1 . Elevated lead in the presence of humic acid appeared to be driven by complexation, with 208 Pb and UV 254 size-exclusion chromatograms exhibiting strong correlation under these conditions (R 2 average = 0.87). A significant iron corrosion effect was consistent with field data: lead levels after lead service line replacement were greater by factors of 2.3-4.7 at sites supplied by unlined cast iron distribution mains compared with the alternative, lined ductile iron.

Respiratory Symptoms and Pulmonary Function Tests among Galvanized Workers Exposed To Zinc Oxide.

PubMed

Aminian, Omid; Zeinodin, Hamidreza; Sadeghniiat-Haghighi, Khosro; Izadi, Nazanin

2015-01-01

Galvanization is the process of coating steel or cast iron pieces with a thin layer of zinc allowing protection against corrosion. One of the important hazards in this industry is exposure to zinc compounds specially zinc oxide fumes and dusts. In this study, we evaluated chronic effects of zinc oxide on the respiratory tract of galvanizers. Overall, 188 workers were selected from Arak galvanization plant in 2012, 71 galvanizers as exposed group and 117 workers from other departments of plants as control group. Information was collected using American Thoracic Society (ATS) standard questionnaire, physical examination and demographic data sheet. Pulmonary function tests were measured for all subjects. Exposure assessment was done with NIOSH 7030 method. The Personal Breathing Zone (PBZ) air sampling results for zinc ranged from 6.61 to 8.25 mg/m³ above the permissible levels (Time weighted average; TWA:2 mg/m³). The prevalence of the respiratory symptoms such as dyspnea, throat and nose irritation in the exposed group was significantly (P<0.01) more than the control group. Decreasing in average percent in all spirometric parameters were seen in the galvanizers who exposed to zinc oxide fumes and dusts. The prevalence of obstructive respiratory disease was significantly (P=0.034) higher in the exposed group. High workplace zinc levels are associated with an increase in respiratory morbidity in galvanizers. Therefore administrators should evaluate these workers with periodic medical examinations and implement respiratory protection program in the working areas.

7 CFR 1755.370 - RUS specification for seven wire galvanized steel strand.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 11 2012-01-01 2012-01-01 false RUS specification for seven wire galvanized steel... steel strand. (a) RUS incorporates by reference ASTM A475-78, Standard Specification for Zinc-Coated Steel Wire Strand, issued May 1978. All seven wire galvanized steel strand purchased after April 1, 1990...

7 CFR 1755.370 - RUS specification for seven wire galvanized steel strand.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 11 2014-01-01 2014-01-01 false RUS specification for seven wire galvanized steel... steel strand. (a) RUS incorporates by reference ASTM A475-78, Standard Specification for Zinc-Coated Steel Wire Strand, issued May 1978. All seven wire galvanized steel strand purchased after April 1, 1990...

7 CFR 1755.370 - RUS specification for seven wire galvanized steel strand.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 11 2013-01-01 2013-01-01 false RUS specification for seven wire galvanized steel... steel strand. (a) RUS incorporates by reference ASTM A475-78, Standard Specification for Zinc-Coated Steel Wire Strand, issued May 1978. All seven wire galvanized steel strand purchased after April 1, 1990...

77 FR 17427 - Notice of Final Determination of Sales at Less Than Fair Value: Galvanized Steel Wire From Mexico

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-26

... Determination of Sales at Less Than Fair Value: Galvanized Steel Wire From Mexico AGENCY: Import Administration... the investigation of sales at less than fair value of galvanized steel wire (galvanized wire) from Mexico.\\1\\ \\1\\ See Galvanized Steel Wire from Mexico: Preliminary Determination of Sales at Less Than...

Finishes for Metals. Paintability of Galvanized Steel, Corrosion Resistance of Metallized Coatings.

ERIC Educational Resources Information Center

Building Research Inst., Inc., Washington, DC.

Two papers are presented. The first, "Report of the AISI Research Project on the Paintability of Galvanized Steel," was a project aimed at determining optimum procedures for painting bright-spangled galvanized sheet steel products using three classes of trade sales paints--metallic zinc-dust, portland cement-in-oil, and water base emulsion paints.…

[Exposure to metal compounds in occupational galvanic processes].

PubMed

Surgiewicz, Jolanta; Domański, Wojciech

2006-01-01

Occupational galvanic processes are provided in more than 600 small and medium enterprises in Poland. Workers who deal with galvanic coating are exposed to heavy metal compounds: tin, silver, copper and zinc. Some of them are carcinogenic, for example, hexavalent chromium compounds, nickel and cadmium compounds. Research covered several tens of workstations involved in chrome, nickel, zinc, tin, silver, copper and cadmium plating. Compounds of metals present in the air were determined: Cr, Ni, Cd, Sn, Ag--by atomic absorption spectrometry with electrothermal atomization (ET-AAS) and Zn--by atomic absorption spectrometry with flame atomization (F-AAS). The biggest metal concentrations--of silver and copper--were found at workstations of copper, brass, cadmium, nickel and chrome plating, conducted at the same time. Significant concentrations of copper were found at workstations of maintenance bathing and neutralizing of sewage. The concentrations of metals did not exceed Polish MAC values. MAC values were not exceeded for carcinogenic chromium(VI), nickel or cadmium, either. In galvanic processes there was no hazard related to single metals or their compounds, even carcinogenic ones. Combined exposure indicators for metals at each workstation did not exceed 1, either. However, if there are even small quantities of carcinogenic agents, health results should always be taken into consideration.

Wear resistance of WC/Co HVOF-coatings and galvanic Cr coatings modified by diamond nanoparticles

NASA Astrophysics Data System (ADS)

Kandeva, M.; Grozdanova, T.; Karastoyanov, D.; Assenova, E.

2017-02-01

The efforts in the recent 20 years are related to search of ecological solutions in the tribotechnologies for the replacement of galvanic Cr coatings in the contact systems operating under extreme conditions: abrasion, erosion, cavitation, corrosion, shock and vibration loads. One of the solutions is in the composite coatings deposited by high velocity gas-flame process (HVOF). The present paper presents comparative study results for mechanical and tribological characteristics of galvanic Cr coatings without nanoparticles, galvanic Cr coatings modified by diamond nanoparticles NDDS of various concentration 0.6; 10; 15 и 20% obtained under three technological regimes, and composite WC-12Co coating. Comparative results about hardness, wear, wear resistance and friction coefficient are obtained for galvanic Cr-NDDS and WC-12Co coatings operating at equal friction conditions of dry friction on abrasive surface. The WC-12Co coating shows 5.4 to 7 times higher wear resistance compared to the galvanic Cr-NDDS coatings.

Investigation of galvanic corrosion in laser-welded stainless steel sheets

NASA Astrophysics Data System (ADS)

Kwok, Chi-Tat; Fong, Siu Lung; Cheng, Fai Tsun; Man, Hau-Chung

2004-10-01

In the present study, bead-on-plate specimens of 1-mm sheets of austenitic and duplex stainless steels were fabricated by laser penetration welding with a 2.5-kW CW Nd:YAG laser. The galvanic corrosion behavior of laser-weldment (LW) against as-received (AR) specimens with an area rato of 1:1 in 3.5% NaCL solution was studied by means of a zero-resistance ammeter. The free corrosion potentials of as-received specimens were found to be considerably higher than those of laser weldments, indicating that the weldments are more active and always act as anodes. The ranking of galvanic current densities (IG) of the couples in ascending order is: AR S31603-LW S31603 < AR S31803-LW S31803 < AR S32760-LW S32760 < AR S30400-LW S30400. For the galvanic couple between AR S30400 and LW S30400, the IG is the highest (78.6 nA/cm2) because large amount of δ-ferrite in the weld zone acts as active sites. On the other hand, the IG of the galvanic couple between AR S31603 and LW S31603 is the lowest (-26 nA/cm2) because no δ-ferrite is present after laser welding. The recorded IG of all couples revealed constantly low values (in the rnage of nA/cm2) and sometimes stayed negative, which indicated polarity reversal.

Cooper pair tunnelling and quasiparticle poisoning in a galvanically isolated superconducting double dot

NASA Astrophysics Data System (ADS)

Esmail, A. A.; Ferguson, A. J.; Lambert, N. J.

2017-12-01

We increase the isolation of a superconducting double dot from its environment by galvanically isolating it from any electrodes. We probe it using high frequency reflectometry techniques, find 2e-periodic behaviour, and characterise the energy structure of its charge states. By modelling the response of the device, we determine the time averaged probability that the device is poisoned by quasiparticles, and by comparing this with previous work, we conclude that quasiparticle exchange between the dots and the leads is an important relaxation mechanism.

Initial evaluation of a convection counter streaming galvanization technique of sex separation of human spermatozoa.

PubMed

Daniell, J F; Herbert, C M; Repp, J; Torbit, C A; Wentz, A C

1982-08-01

A new method for separating X and Y human spermatozoa called convection counter streaming galvanization was evaluated. The method was independently performed by this semenology laboratory with the use of the special separation equipment and extending media provided by its developer, Dr. Bhairab C. Bhattacharya. The mean number of Y spermatozoa increased from 48% to 77% in the separated fraction predicted to be Y-enriched. The fraction predicted to be X-enriched increased from a mean of 52% to 77%. The one separation process allowed accumulation of both enriched fractions simultaneously. The separated portions of spermatozoa maintained good motility and penetration of cervical mucus but produced a mean recovery concentration in the X- and Y-enriched fractions of only 15% to 16% of the preseparation concentration.

[Contribution of Aleksander Sapieha (1773-1812) into European galvanization therapy].

PubMed

Gorski, P; Goetz, W

1996-01-01

For the development of the therapy using electricity as agent two tracks can be identified. On the one side, the indication for applying this therapy was handled more careful, simultaneously the technical equipment was improved. The Polish noble man Alexander Sapieha (1773-1812), the leading natural scientist of the Granddukedom of Warsaw, cooperated with excellent European scientists in order to improve the galvanic battery technologically. Among these scientists were Alexander Volta (1745-1827), the inventor of the battery, and Johann Bartholomaeus Trommsdorff (1770-1837), who is considered as one of the founders of scientific pharmacy in Europe. A. Sapieha supported the publication of galvanic experiences, e.g. in the case of Alexander of Humboldt (1769-1859) by publishing his paper about electric fishes. Sapiehas connections with the scientific centers in Turin and Bologna, Erfurt, Warszaw and Paris accelerated the exchange of information about galvanism. Later the resulting mini-batteries were employed in diathermie, in defibrillators and pacemakers. Details about these connections are presented in the lecture resp. full paper.

SERS activity studies of Ag/Au bimetallic films prepared by galvanic replacement

NASA Astrophysics Data System (ADS)

Wang, Chaonan; Fang, Jinghuai; Jin, Yonglong

2012-10-01

Ag films on Si substrates were fabricated by immersion plating, which served as sacrificial materials for preparation of Ag/Au bimetallic films by galvanic replacement method. SEM images displayed that the sacrificial Ag films presenting island morphology experienced interesting structural evolution process during galvanic replacement reaction, and nano-scaled holes were formed in the resultant bimetallic films. SERS measurements using crystal violet as an analyte showed that SERS intensities of bimetallic films were enhanced significantly compared with that of pure Ag films and related mechanisms were discussed. Immersion plating experiment carried out on Ag films on PEN substrates fabricated by photoinduced reduction method further confirmed that galvanic replacement is an easy method to fabricate Ag/Au bimetallic and a potential approach to improve the SERS performance of Ag films.

Zinc toxicity among galvanization workers in the iron and steel industry.

PubMed

El Safty, Amal; El Mahgoub, Khalid; Helal, Sawsan; Abdel Maksoud, Neveen

2008-10-01

Galvanization is the process of coating steel or cast iron pieces with zinc, allowing complete protection against corrosion. The ultimate goal of this work was to assess the effect of occupational exposure to zinc in the galvanization process on different metals in the human body and to detect the association between zinc exposure and its effect on the respiratory system. This study was conducted in 111 subjects in one of the major companies in the iron and steel industry. There were 61 subjects (workers) who were involved in the galvanization process. Fifty adult men were chosen as a matched reference group from other departments of the company. All workers were interviewed using a special questionnaire on occupational history and chest diseases. Ventilatory functions and chest X rays were assessed in all examined workers. Also, complete blood counts were performed, and serum zinc, iron, copper, calcium, and magnesium levels were tested. This study illustrated the relation between zinc exposure in the galvanization process and high zinc levels among exposed workers, which was associated with a high prevalence rate of metal fume fever (MFF) and low blood copper and calcium levels. There was no statistically significant difference between the exposed and control groups with regards to the magnesium level. No long-term effect of metals exposure was detected on ventilatory functions or chest X rays among the exposed workers.

Autonomous colloidal crystallization in a galvanic microreactor

NASA Astrophysics Data System (ADS)

Punckt, Christian; Jan, Linda; Jiang, Peng; Frewen, Thomas A.; Saville, Dudley A.; Kevrekidis, Ioannis G.; Aksay, Ilhan A.

2012-10-01

We report on a technique that utilizes an array of galvanic microreactors to guide the assembly of two-dimensional colloidal crystals with spatial and orientational order. Our system is comprised of an array of copper and gold electrodes in a coplanar arrangement, immersed in a dilute hydrochloric acid solution in which colloidal micro-spheres of polystyrene and silica are suspended. Under optimized conditions, two-dimensional colloidal crystals form at the anodic copper with patterns and crystal orientation governed by the electrode geometry. After the aggregation process, the colloidal particles are cemented to the substrate by co-deposition of reaction products. As we vary the electrode geometry, the dissolution rate of the copper electrodes is altered. This way, we control the colloidal motion as well as the degree of reaction product formation. We show that particle motion is governed by a combination of electrokinetic effects acting directly on the colloidal particles and bulk electrolyte flow generated at the copper-gold interface.

In vitro cytotoxicity of galvanically coupled magnesium-titanium particles on human osteosarcoma SAOS2 cells: A potential cancer therapy.

PubMed

Kim, Jua; Gilbert, Jeremy L

2018-04-10

Osteosarcoma is a malignant bone cancer that occurs mostly in children and young adults. This study investigated the cytotoxicity of Mg and Mg-Ti microparticles to human osteosarcoma cells. Osteosarcoma cells were killed in a dosage-dependent manner when cells, with a cell seeding density of 30,000 cells/cm 2 , were cultured with 0 to 2500 µg/mL of Mg or Mg-Ti in cell culture media for 24-72 h. Mg-Ti killed cells more effectively, where 1250 µg/mL of Mg-Ti killed cells completely by 24 h, while 2500 µg/mL of Mg killed nearly all cells, but not all. Killing due to particle corrosion occurred mostly during the first 24 h, and so the percent cell viability between 24 and 72 h showed not much variability. However, the measurement of live and dead cell numbers, over the timeframe of 24-72 h, showed more insight, such as cell recovery. If particle concentrations were low, the number of live cells increased after 24 h, indicating cell proliferation. If particle concentrations were high, the number of live cells either remained steady or decreased, indicating cell quiescence or continued killing, respectively. Increase in the number of dead cells also indicated killing, while plateau meant discontinued killing. In addition, repeated killing of recovered cells exhibited the same dose-dependent killing profile as the initial experiment, implying little development of cell resistance to treatment. These results, together, show that osteosarcoma cells are susceptible to killing by way of exposure to corroding particles, showing highly effective killing using the galvanic couple of Mg-Ti. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2018. © 2018 Wiley Periodicals, Inc.

76 FR 72721 - Galvanized Steel Wire From China and Mexico; Scheduling of the Final Phase of Countervailing Duty...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-25

...)] Galvanized Steel Wire From China and Mexico; Scheduling of the Final Phase of Countervailing Duty and... galvanized steel wire, provided for in subheading 7217.20 of the Harmonized Tariff Schedule of the United... merchandise as galvanized steel wire which is a cold- drawn carbon quality steel product in coils, of solid...

Galvanic corrosion behaviors of Cu connected to Au on a printed circuit board in ammonia solution

NASA Astrophysics Data System (ADS)

Oh, SeKwon; Kim, YoungJun; Jung, KiMin; Park, MiSeok; Shon, MinYoung; Kwon, HyukSang

2018-01-01

During etching treatments of printed circuit board (PCB) with ammnioa solution, galvanic corrosion occurs between electrically connected gold and copper, and resulting in unexpected over-etching problems. Herein, we determine corrosion of galvanic coupled Cu to Au quantitatively in ammonia solutions, and evaluate factors influencing corrosion of galvanic coupled Cu to Au (i.e., area ratio of anode to cathode and stirring speed). The difference of the corrosion rate (Δi = icouple, (Cu-Au)-icorr, Cu) of Cu connected to Au (117 μA/cm2) and of single Cu (86 μA/cm2) infers the amount of over-etching of Cu resulting from galvanic corrosion in ammonia solution (Δi = 0.31 μA/cm2). As the stirring speed increases from 0 to 400 rpm, the corrosion rate of galvanic coupled Cu to Au increases from 36 to 191 μA/cm2. Furthermore, we confirm that an increase in the area ratio (Au/Cu) from 0.5 to 25 results in a higher rate of corrosion of Cu connected to Au. The corrosion rate of galvanic coupled Cu to Au is approximately 20 times higher when the area ratio of Au to Cu is 25 (1360 μA/cm2) than when the ratio is 0.5 (67 μA/cm2).

Inertization of heavy metals present in galvanic sludge by DC thermal plasma.

PubMed

Leal Vieira Cubas, Anelise; de Medeiros Machado, Marília; de Medeiros Machado, Marina; Gross, Frederico; Magnago, Rachel Faverzani; Moecke, Elisa Helena Siegel; Gonçalvez de Souza, Ivan

2014-01-01

Galvanic sludge results from the treatment of effluents generated by the industrial metal surface treatment of industrial material, which consists in the deposition of a metal on a surface or a metal surface attack, for example, electrodeposition of conductors (metals) and non conductive, phosphate, anodizing, oxidation and/or printed circuit. The treatment proposed here is exposure of the galvanic sludge to the high temperatures provided by thermal plasma, a process which aims to vitrify the galvanic sludge and render metals (iron, zinc, and chromium) inert. Two different plasma reactors were assembled: with a DC transferred arc plasma torch and with a DC nontransferred arc plasma torch. In this way it was possible to verify which reactor was more efficient in the inertization of the metals and also to investigate whether the addition of quartzite sand to the sludge influences the vitrification of the material. Quantification of water content and density of the galvanic raw sludge were performed, as well as analyzes of total organic carbon (TOC) and identify the elements that make up the raw sludge through spectroscopy X-ray fluorescence (XRF). The chemical composition and the form of the pyrolyzed and vitrified sludge were analyzed by scanning electron microscopy with energy-dispersive X-ray spectrometer (SEM-EDS) analysis, which it is a analysis that shows the chemical of the sample surface. The inertization of the sludge was verified in leaching tests, where the leachate was analyzed by flame atomic absorption spectroscopy (FAAS). The results of water content and density were 64.35% and 2.994 g.cm(-3), respectively. The TOC analysis determined 1.73% of C in the sample of galvanic raw sludge, and XRF analysis determined the most stable elements in the sample, and showed the highest peaks (higher stability) were Fe, Zn, and Cr. The efficiency of the sludge inertization was 100% for chromium, 99% for zinc, and 100% for iron. The results also showed that the most

Influence of stripping and cooling atmospheres on surface properties and corrosion of zinc galvanizing coatings

NASA Astrophysics Data System (ADS)

Yasakau, K. A.; Giner, I.; Vree, C.; Ozcan, O.; Grothe, R.; Oliveira, A.; Grundmeier, G.; Ferreira, M. G. S.; Zheludkevich, M. L.

2016-12-01

In this work the influence of stripping/cooling atmospheres used after withdrawal of steel sheet from Zn or Zn-alloy melt on surface properties of Zn (Z) and Zn-Al-Mg (ZM) hot-dip galvanizing coatings has been studied. The aim was to understand how the atmosphere (composed by nitrogen (N2) or air) affects adhesion strength to model adhesive and corrosive behaviour of the galvanized substrates. It was shown that the surface chemical composition and Volta potential of the galvanizing coatings prepared under the air or nitrogen atmosphere are strongly influenced by the atmosphere. The surface chemistry Z and ZM surfaces prepared under N2 contained a higher content of metal atoms and a richer hydroxide density than the specimens prepared under air atmosphere as assessed by X-ray photoelectron spectroscopy (XPS). The induced differences on the microstructure of the galvanized coatings played a key role on the local corrosion induced defects as observed by means of in situ Atomic force microscopy (AFM). Peel force tests performed on the substrates coated by model adhesive films indicate a higher adhesive strength to the surfaces prepared under nitrogen atmosphere. The obtained results have been discussed in terms of the microstructure and surface chemical composition of the galvanizing coatings.

Effectiveness of low-cost electromagnetic shielding using nail-together galvanized steel: Test results. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Williams, P.F.; Kennedy, E.L.; McCormack, R.G.

1992-09-01

The sensitivity of modern electronic equipment has increased the need for costly electromagnetic shielding. To reduce this cost, the U.S. Army Construction Engineering Research Laboratories (USACERL) has developed a new concept for shielding design that uses 28-gauge galvanized steel and standard galvanized nails. In this study, an electromagnetically shielded structure using the concept was designed, built, and evaluated for shielding effectiveness. The galvanized material was mounted to the standard USACERL test aperture and nailed to the wooden module frame, and the shielding effectiveness of the new construction design was measured using radio frequency antennas and receivers. Evaluations showed that themore » nail-together structure proved adequate for many shielding applications. However, while the galvanized steel met most shielding application requirements, this process added multiple seams to the structure, which decreased shielding in many instances by as much as 40 dB. Electromagnetic shielding, Electromagnetic pulse C3I Facilities.« less

Galvanic vestibular stimulation speeds visual memory recall.

PubMed

Wilkinson, David; Nicholls, Sophie; Pattenden, Charlotte; Kilduff, Patrick; Milberg, William

2008-08-01

The experiments of Alessandro Volta were amongst the first to indicate that visuo-spatial function can be altered by stimulating the vestibular nerves with galvanic current. Until recently, the beneficial effects of the procedure were masked by the high levels of electrical current applied, which induced nystagmus-related gaze deviation and spatial disorientation. However, several neuropsychological studies have shown that much weaker, imperceptible currents that do not elicit unpleasant side-effects can help overcome visual loss after stroke. Here, we show that visual processing in neurologically healthy individuals can also benefit from galvanic vestibular stimulation. Participants first learnt the names of eight unfamiliar faces and then after a short delay, answered questions from memory about how pairs of these faces differed. Mean correct reaction times were significantly shorter when sub-sensory, noise-enhanced anodal stimulation was administered to the left mastoid, compared to when no stimulation was administered at all. This advantage occurred with no loss in response accuracy, and raises the possibility that the procedure may constitute a more general form of cognitive enhancement.

Corrosion protection of galvanized steels by silane-based treatments

NASA Astrophysics Data System (ADS)

Yuan, Wei

The possibility of using silane coupling agents as replacements for chromate treatments was investigated on galvanized steel substrates. In order to understand the influence of deposition parameters on silane film formation, pure zinc substrates were first used as a model for galvanized steel to study the interaction between silane coupling agents and zinc surfaces. The silane films formed on pure zinc substrates from aqueous solutions were characterized by ellipsometry, contact angle measurements, reflection absorption infrared spectroscopy, x-ray photoelectron spectroscopy, and atomic force microscopy. The deposition parameters studied include solution concentration, solution dipping time and pH value of the applied solution. It appears that silane film formation involved a true equilibrium of hydrolysis and condensation reactions in aqueous solutions. It has been found that the silane film thickness obtained depends primarily on the solution concentration and is almost independent of the solution dipping time. The molecular orientation of applied silane films is determined by the pH value of applied silane solutions and the isoelectric point of metal substrates. The deposition window in terms of pH value for zinc substrates is between 6.0 and 9.0. The total surface energy of the silane-coated pure zinc substrates decreases with film aging time, the decrease rate, however, is determined by the nature of silane coupling agents. Selected silane coupling agents were applied as prepaint or passivation treatments onto galvanized steel substrates. The corrosion protection provided by these silane-based treatments were evaluated by salt spray test, cyclic corrosion test, electrochemical impedance spectroscopy, and stack test. The results showed that silane coupling agents can possibly be used to replace chromates for corrosion control of galvanized steel substrates. Silane coatings provided by these silane treatments serve mainly as physical barriers. Factors that

Galvanic corrosion behavior of orthodontic archwire alloys coupled to bracket alloys.

PubMed

Iijima, Masahiro; Endo, Kazuhiko; Yuasa, Toshihiro; Ohno, Hiroki; Hayashi, Kazuo; Kakizaki, Mitsugi; Mizoguchi, Itaru

2006-07-01

The purpose of this study was to provide a quantitative assessment of galvanic corrosion behavior of orthodontic archwire alloys coupled to orthodontic bracket alloys in 0.9% NaCl solution and to study the effect of surface area ratios. Two common bracket alloys, stainless steels and titanium, and four common wire alloys, nickel-titanium (NiTi) alloy, beta-titanium (beta-Ti) alloy, stainless steel, and cobalt-chromium-nickel alloy, were used. Three different area ratios, 1:1, 1:2.35, and 1:3.64, were used; two of them assumed that the multibracket appliances consists of 14 brackets and 0.016 inch of round archwire or 0.016 x 0.022 inch of rectangular archwire. The galvanic current was measured for 3 successive days using zero-impedance ammeter. When the NiTi alloy was coupled with Ti (1:1, 1:2.35, and 1:3.64 of the surface area ratio) or beta-Ti alloy was coupled with Ti (1:2.35 and 1:3.64 of the surface area ratio), Ti initially was the anode and corroded. However, the polarity reversed in 1 hour, resulting in corrosion of the NiTi or beta-Ti. The NiTi alloy coupled with SUS 304 or Ti exhibited a relatively large galvanic current density even after 72 hours. It is suggested that coupling SUS 304-NiTi and Ti-NiTi may remarkably accelerate the corrosion of NiTi alloy, which serves as the anode. The different anode-cathode area ratios used in this study had little effect on galvanic corrosion behavior.

Galvanic Corrosion In (Graphite/Epoxy)/Alloy Couples

NASA Technical Reports Server (NTRS)

Danford, Merlin D.; Higgins, Ralph H.

1988-01-01

Effects of galvanic coupling between graphite/epoxy composite material, G/E, and D6AC steel, 6061-T6 aluminum, and Inconel(R) 718 nickel alloy in salt water described in report. Introductory section summarizes previous corrosion studies of G/E with other alloys. Details of sample preparation presented along with photographs of samples before and after immersion.

Galvanic interactions of HE15 /MDN138 & HE15 /MDN250 alloys in natural seawater

NASA Astrophysics Data System (ADS)

Parthiban, G. T.; Subramanian, G.; Muthuraman, K.; Ramakrishna Rao, P.

2017-06-01

HE15 is a heat treatable high strength alloy with excellent machinability find wide applications in aerospace and defence industries. In view of their excellent mechanical properties, workability, machinability, heat treatment characteristics and good resistance to general and stress corrosion cracking, MDN138 & MDN250 have been widely used in petrochemical, nuclear and aerospace industries. The galvanic corrosion behaviour of the metal combinations HE15 /MDN138 and HE15 /MDN250, with 1:1 area ratio, has been studied in natural seawater using the open well facility of CECRI's Offshore Platform at Tuticorin for a year. The open circuit potentials of MDN138, MDN250 and HE15 of the individual metal, the galvanic potential and galvanic current of the couples HE15 /MDN138 and HE15 /MDN250 were periodically monitored throughout the study period. The calcareous deposits on MDN138 and MDN250 in galvanic contact with HE15 were analyzed using XRD. The electrochemical behaviors of MDN138, MDN250 and HE15 in seawater have been studied using an electrochemical work station. The surface characteristics of MDN138 and MDN250 in galvanic contact with HE15 have been examined with scanning electron microscope. The results of the study reveal that HE15 offered required amount of protection to MDN138 & MDN250.

76 FR 23564 - Galvanized Steel Wire From the People's Republic of China: Initiation of Countervailing Duty...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-27

... the People's Republic of China: Initiation of Countervailing Duty Investigation AGENCY: Import... a countervailing duty (CVD) petition concerning imports of galvanized steel wire from the People's... Duties on Galvanized Steel Wire from the People's Republic of China'' (CVD Petition). On April 6, 2011...

Electrochemical Behaviour and Galvanic Effects of Titanium Implants Coupled to Metallic Suprastructures in Artificial Saliva

PubMed Central

Mellado-Valero, Ana; Igual Muñoz, Anna; Guiñón Pina, Virginia

2018-01-01

The aim of the present study is to analyze the electrochemical behavior of five different dental alloys: two cobalt-chromium alloys (CoCr and CoCr-c), one nickel-chromium-titanium alloy (NiCrTi), one gold-palladium alloy (Au), and one titanium alloy (Ti6Al4V), and the galvanic effect when they are coupled to titanium implants (TiG2). It was carried out by electrochemical techniques (open circuit measurements, potentiodynamic curves and Zero-Resistance Ammetry) in artificial saliva (AS), with and without fluorides in different acidic conditions. The studied alloys are spontaneously passivated, but NiCrTi alloy has a very narrow passive domain and losses its passivity in presence of fluorides, so is not considered as a good option for implant superstructures. Variations of pH from 6.5 to 3 in artificial saliva do not change the electrochemical behavior of Ti, Ti6Al4V, and CoCr alloys, and couples, but when the pH of the artificial saliva is below 3.5 and the fluoride content is 1000 ppm Ti and Ti6Al4V starts actively dissolving, and CoCr-c superstructures coupled to Ti show acceleration of corrosion due to galvanic effects. Thus, NiCrTi is not recommended for implant superstructures because of risk of Ni ion release to the body, and fluorides should be avoided in acidic media because Ti, Ti6Al4V, and CoCr-c superstructures show galvanic corrosion. The best combinations are Ti/Ti6Al4V and Ti/CoCr as alternative of noble gold alloys. PMID:29361767

Electrochemical Behaviour and Galvanic Effects of Titanium Implants Coupled to Metallic Suprastructures in Artificial Saliva.

PubMed

Mellado-Valero, Ana; Muñoz, Anna Igual; Pina, Virginia Guiñón; Sola-Ruiz, Ma Fernanda

2018-01-22

The aim of the present study is to analyze the electrochemical behavior of five different dental alloys: two cobalt-chromium alloys (CoCr and CoCr-c), one nickel-chromium-titanium alloy (NiCrTi), one gold-palladium alloy (Au), and one titanium alloy (Ti6Al4V), and the galvanic effect when they are coupled to titanium implants (TiG2). It was carried out by electrochemical techniques (open circuit measurements, potentiodynamic curves and Zero-Resistance Ammetry) in artificial saliva (AS), with and without fluorides in different acidic conditions. The studied alloys are spontaneously passivated, but NiCrTi alloy has a very narrow passive domain and losses its passivity in presence of fluorides, so is not considered as a good option for implant superstructures. Variations of pH from 6.5 to 3 in artificial saliva do not change the electrochemical behavior of Ti, Ti6Al4V, and CoCr alloys, and couples, but when the pH of the artificial saliva is below 3.5 and the fluoride content is 1000 ppm Ti and Ti6Al4V starts actively dissolving, and CoCr-c superstructures coupled to Ti show acceleration of corrosion due to galvanic effects. Thus, NiCrTi is not recommended for implant superstructures because of risk of Ni ion release to the body, and fluorides should be avoided in acidic media because Ti, Ti6Al4V, and CoCr-c superstructures show galvanic corrosion. The best combinations are Ti/Ti6Al4V and Ti/CoCr as alternative of noble gold alloys.

Micro Galvanic Cell To Generate PtO and Extend the Triple-Phase Boundary during Self-Assembly of Pt/C and Nafion for Catalyst Layers of PEMFC.

PubMed

Long, Zhi; Gao, Liqin; Li, Yankai; Kang, Baotao; Lee, Jin Yong; Ge, Junjie; Liu, Changpeng; Ma, Shuhua; Jin, Zhao; Ai, Hongqi

2017-11-08

The self-assembly powder (SAP) with varying Nafion content was synthesized and characterized by XRD, XPS, HRTEM, and mapping. It is observed that the oxygen from oxygen functional groups transfers to the surface of Pt and generate PtO during the process of self-assembly with the mechanism of micro galvanic cell, where Pt, carbon black, and Nafion act as the anode, cathode and electrolyte, respectively. The appearance of PtO on the surface of Pt leads to a turnover of Nafion structure, and therefore more hydrophilic sulfonic groups directly contact with Pt, and thus the triple-phase boundary (TPB) has been expanded.

Saccule contribution to immediate early gene induction in the gerbil brainstem with posterior canal galvanic or hypergravity stimulation

NASA Technical Reports Server (NTRS)

Marshburn, T. H.; Kaufman, G. D.; Purcell, I. M.; Perachio, A. A.

1997-01-01

Immunolabeling patterns of the immediate early gene-related protein Fos in the gerbil brainstem were studied following stimulation of the sacculus by both hypergravity and galvanic stimulation. Head-restrained, alert animals were exposed to a prolonged (1 h) inertial vector of 2 G (19.6 m/s2) head acceleration directed in a dorso-ventral head axis to maximally stimulate the sacculus. Fos-defined immunoreactivity was quantified, and the results compared to a control group. The hypergravity stimulus produced Fos immunolabeling in the dorsomedial cell column (dmcc) of the inferior olive independently of other subnuclei. Similar dmcc labeling was induced by a 30 min galvanic stimulus of up to -100 microA applied through a stimulating electrode placed unilaterally on the bony labyrinth overlying the posterior canal (PC). The pattern of vestibular afferent firing activity induced by this galvanic stimulus was quantified in anesthetized gerbils by simultaneously recording from Scarpa's ganglion. Only saccular and PC afferent neurons exhibited increases in average firing rates of 200-300%, suggesting a pattern of current spread involving only PC and saccular afferent neurons at this level of stimulation. These results suggest that alteration in saccular afferent firing rates are sufficient to induce Fos-defined genomic activation of the dmcc, and lend further evidence to the existence of a functional vestibulo-olivary-cerebellar pathway of adaptation to novel gravito-inertial environments.

South approach, looking north. The galvanized piping extends from the ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

South approach, looking north. The galvanized piping extends from the abutments across the length of the arch. - Weaverland Bridge, Quarry Road spanning Conestoga Creek, Terre Hill, Lancaster County, PA

Thunderbolt in biogeochemistry: galvanic effects of lightning as another source for metal remobilization.

PubMed

Schaller, Jörg; Weiske, Arndt; Berger, Frank

2013-11-04

Iron and manganese are relevant constituents of the earth's crust and both show increasing mobility when reduced by free electrons. This reduction is known to be controlled by microbial dissimilation processes. Alternative sources of free electrons in nature are cloud-to-ground lightning events with thermal and galvanic effects. Where thermal effects of lightning events are well described, less is known about the impact of galvanic lightning effects on metal mobilization. Here we show that a significant mobilization of manganese occurs due to galvanic effects of both positive and negative lightning, where iron seems to be unaffected with manganese being abundant in oxic forms in soils/sediments. A mean of 0.025 mmol manganese (negative lightning) or 0.08 mmol manganese (positive lightning) mobilization may occur. We suggest that lightning possibly influences biogeochemical cycles of redox sensitive elements in continental parts of the tropics/subtropics on a regional/local scale.

1. Elkmont vehicle bridge at Elkmont Campground, galvanized corrugated arch. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. Elkmont vehicle bridge at Elkmont Campground, galvanized corrugated arch. - Great Smoky Mountains National Park Roads & Bridges, Elkmont Vehicle Bridge, Spanning Little River at Elkmont Campground, Gatlinburg, Sevier County, TN

Optimization of laser welding thin-gage galvanized steel via response surface methodology

NASA Astrophysics Data System (ADS)

Zhao, Yangyang; Zhang, Yansong; Hu, Wei; Lai, Xinmin

2012-09-01

The increasing demand of light weight and durability makes thin-gage galvanized steels (<0.6 mm) attractive for future automotive applications. Laser welding, well known for its deep penetration, high speed and small heat affected zone, provides a potential solution for welding thin-gage galvanized steels in automotive industry. In this study, the effect of the laser welding parameters (i.e. laser power, welding speed, gap and focal position) on the weld bead geometry (i.e. weld depth, weld width and surface concave) of 0.4 mm-thick galvanized SAE1004 steel in a lap joint configuration has been investigated by experiments. The process windows of the concerned process parameters were therefore determined. Then, response surface methodology (RSM) was used to develop models to predict the relationship between the processing parameters and the laser weld bead profile and identify the correct and optimal combination of the laser welding input variables to obtain superior weld joint. Under the optimal welding parameters, defect-free weld were produced, and the average aspect ratio increased about 30%, from 0.62 to 0.83.

Thunderbolt in biogeochemistry: galvanic effects of lightning as another source for metal remobilization

PubMed Central

Schaller, Jörg; Weiske, Arndt; Berger, Frank

2013-01-01

Iron and manganese are relevant constituents of the earth's crust and both show increasing mobility when reduced by free electrons. This reduction is known to be controlled by microbial dissimilation processes. Alternative sources of free electrons in nature are cloud-to-ground lightning events with thermal and galvanic effects. Where thermal effects of lightning events are well described, less is known about the impact of galvanic lightning effects on metal mobilization. Here we show that a significant mobilization of manganese occurs due to galvanic effects of both positive and negative lightning, where iron seems to be unaffected with manganese being abundant in oxic forms in soils/sediments. A mean of 0.025 mmol manganese (negative lightning) or 0.08 mmol manganese (positive lightning) mobilization may occur. We suggest that lightning possibly influences biogeochemical cycles of redox sensitive elements in continental parts of the tropics/subtropics on a regional/local scale. PMID:24184989

76 FR 68407 - Galvanized Steel Wire From the People's Republic of China: Preliminary Determination of Sales at...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-04

..., shorter strands of galvanized wire are purely for non-industrial, personal use, this galvanized [[Page... Co.; Nantong Long Yang International Trade Co., Ltd.; Shaanxi New Mile International Trade Co. Ltd... per capita gross national income are comparable to the PRC in terms of economic development.\\20\\ On...

Use of ssq rotational invariant of magnetotelluric impedances for estimating informative properties for galvanic distortion

NASA Astrophysics Data System (ADS)

Rung-Arunwan, T.; Siripunvaraporn, W.; Utada, H.

2017-06-01

Several useful properties and parameters—a model of the regional mean one-dimensional (1D) conductivity profile, local and regional distortion indicators, and apparent gains—were defined in our recent paper using two rotational invariants (det: determinant and ssq: sum of squared elements) from a set of magnetotelluric (MT) data obtained by an array of observation sites. In this paper, we demonstrate their characteristics and benefits through synthetic examples using 1D and three-dimensional (3D) models. First, a model of the regional mean 1D conductivity profile is obtained using the average ssq impedance with different levels of galvanic distortion. In contrast to the Berdichevsky average using the average det impedance, the average ssq impedance is shown to yield a reliable estimate of the model of the regional mean 1D conductivity profile, even when severe galvanic distortion is contained in the data. Second, the local and regional distortion indicators were found to indicate the galvanic distortion as expressed by the splitting and shear parameters and to quantify their strengths in individual MT data and in the dataset as a whole. Third, the apparent gain was also shown to be a good approximation of the site gain, which is generally claimed to be undeterminable without external information. The model of the regional mean 1D profile could be used as an initial or a priori model in higher-dimensional inversions. The local and regional distortion indicators and apparent gains could be used to examine the existence and to guess the strength of the galvanic distortion. Although these conclusions were derived from synthetic tests using the Groom-Bailey distortion model, additional tests with different distortion models indicated that these conclusions are not strongly dependent on the choice of distortion model. These galvanic-distortion-related parameters would also assist in judging if a proper treatment is needed for the galvanic distortion when an MT

21 CFR 882.1540 - Galvanic skin response measurement device.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Galvanic skin response measurement device. 882.1540 Section 882.1540 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES NEUROLOGICAL DEVICES Neurological Diagnostic Devices § 882.1540...

Pseudarthrosis due to galvanic corrosion presenting as subarachnoid hemorrhage.

PubMed

Beavers, Rosemary Noel; Lall, Rishi Rajiv; Barnett, Juan Ortega; Desai, Sohum Kiran

2017-01-01

Two unlike metals near one another can break down as they move toward electrochemical equilibrium resulting in galvanic corrosion. We describe a case of electrochemical corrosion resulting in pseudarthrosis, followed by instrumentation failure leading to subarachnoid hemorrhage. A 53-year-old female with a history of cervical instability and two separate prior cervical fusion surgery with sublaminar cables presented with new onset severe neck pain. Restricted range of motion in her neck and bilateral Hoffman's was noted. X-ray of her cervical spine was negative. A noncontrast CT scan of her head and neck showed subarachnoid hemorrhage in the prepontine and cervicomedullary cisterns. Neurosurgical intervention involved removal of prior stainless steel and titanium cables, repair of cerebrospinal fluid leak, and nonsegmental C1-C3 instrumented fusion. She tolerated the surgery well and followed up without complication. Galvanic corrosion of the Brook's fusion secondary to current flow between dissimilar metal alloys resulted in catastrophic instrumentation failure and subarachnoid hemorrhage.

Microstructure and Mechanical Properties of Plasma Arc Brazed AISI 304L Stainless Steel and Galvanized Steel Plates

NASA Astrophysics Data System (ADS)

Jin, Yajuan; Li, Ruifeng; Yu, Zhishui; Wang, Yu

2016-04-01

Plasma arc brazing is used to join the AISI 304L stainless steel and galvanized steel plate butt joints with the CuSi3Mn1 filler wire. The effect of parameters on weld surface appearance, interfacial microstructure, and composition distribution in the joint was studied. The microhardness and mechanical tests were conducted to determine the mechanical properties of the welded specimens. The results indicated that good appearance, bead shape, and sufficient metallurgical bonding could be obtained when the brazing process was performed with a wire feeding speed of 0.8 m/min, plasma gas flow rate of 3.0 l/min, welding current of 100 A, and welding speed of 27 cm/min. During plasma arc brazing process, the top corner of the stainless steel and galvanized steel plate were heated and melted, and the melted quantity of stainless steel was much more than that of the galvanized steel due to the thermal conductivity coefficient difference between the dissimilar materials. The microhardness test results shows that the microhardness value gradually increased from the side of the galvanized steel to the stainless steel in the joint, and it is good for improving the mechanical properties of joint. The tensile strength was a little higher than that of the brazing filler, and the fracture position of weld joint was at the base metal of galvanized steel plate.

Experimental galvanic anode for cathodic protection of Bridge A12112

DOT National Transportation Integrated Search

2010-11-01

Cathodic Protection (CP) has been used by MoDOT for more than 30 years to stop : corrosion of reinforced concrete bridge decks. These systems require power from local electrical : connections. A galvanic system uses the difference in electrical poten...

76 FR 21914 - Galvanized Steel Wire From China and Mexico

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-19

... INTERNATIONAL TRADE COMMISSION [Investigation Nos. 701-TA-479 and 731-TA-1183-1184 (Preliminary)] Galvanized Steel Wire From China and Mexico AGENCY: United States International Trade Commission. ACTION: Revised schedule for the subject antidumping and countervailing duty investigations. DATES: Effective Date...

A Novel Field-Circuit FEM Modeling and Channel Gain Estimation for Galvanic Coupling Real IBC Measurements.

PubMed

Gao, Yue-Ming; Wu, Zhu-Mei; Pun, Sio-Hang; Mak, Peng-Un; Vai, Mang-I; Du, Min

2016-04-02

Existing research on human channel modeling of galvanic coupling intra-body communication (IBC) is primarily focused on the human body itself. Although galvanic coupling IBC is less disturbed by external influences during signal transmission, there are inevitable factors in real measurement scenarios such as the parasitic impedance of electrodes, impedance matching of the transceiver, etc. which might lead to deviations between the human model and the in vivo measurements. This paper proposes a field-circuit finite element method (FEM) model of galvanic coupling IBC in a real measurement environment to estimate the human channel gain. First an anisotropic concentric cylinder model of the electric field intra-body communication for human limbs was developed based on the galvanic method. Then the electric field model was combined with several impedance elements, which were equivalent in terms of parasitic impedance of the electrodes, input and output impedance of the transceiver, establishing a field-circuit FEM model. The results indicated that a circuit module equivalent to external factors can be added to the field-circuit model, which makes this model more complete, and the estimations based on the proposed field-circuit are in better agreement with the corresponding measurement results.

Influence of the Manufacturing Process on Defects in the Galvanized Coating of High Carbon Steel Wires.

PubMed

Gelfi, Marcello; Solazzi, Luigi; Poli, Sandro

2017-03-06

This study is a detailed failure analysis of galvanized high carbon steel wires, which developed coating cracks during the torsion test performed as a quality control at the end of the manufacturing process. Careful visual inspections showed that the cracks are already present in the coating before the torsion test. In order to explain the origin of these cracks, systematic metallographic investigations were performed by means of optical and scanning electron microscope on both the wires and the rods that have been cold drawn to produce the wire. The chemical composition of the galvanized coatings was evaluated by means of energy dispersive spectroscopy. Micro bidimensional X-ray diffraction experiments were also performed to measure the residual stresses in the galvanized coating. The results showed that the failure is related to two main factors: the relatively high content of silicon in the steel and the unsuitable cooling rate of the rods at the exit from the galvanizing bath. The mechanism proposed to explain the origin of the defects was supported by Finite Elements Methods simulations and verified with in-plant tests. The proper countermeasures were then applied and the problem successfully solved.

Influence of the Manufacturing Process on Defects in the Galvanized Coating of High Carbon Steel Wires

PubMed Central

Gelfi, Marcello; Solazzi, Luigi; Poli, Sandro

2017-01-01

This study is a detailed failure analysis of galvanized high carbon steel wires, which developed coating cracks during the torsion test performed as a quality control at the end of the manufacturing process. Careful visual inspections showed that the cracks are already present in the coating before the torsion test. In order to explain the origin of these cracks, systematic metallographic investigations were performed by means of optical and scanning electron microscope on both the wires and the rods that have been cold drawn to produce the wire. The chemical composition of the galvanized coatings was evaluated by means of energy dispersive spectroscopy. Micro bidimensional X-ray diffraction experiments were also performed to measure the residual stresses in the galvanized coating. The results showed that the failure is related to two main factors: the relatively high content of silicon in the steel and the unsuitable cooling rate of the rods at the exit from the galvanizing bath. The mechanism proposed to explain the origin of the defects was supported by Finite Elements Methods simulations and verified with in-plant tests. The proper countermeasures were then applied and the problem successfully solved. PMID:28772623

Galvanic deposition and characterization of brushite/hydroxyapatite coatings on 316L stainless steel.

PubMed

Blanda, Giuseppe; Brucato, Valerio; Pavia, Francesco Carfì; Greco, Silvia; Piazza, Salvatore; Sunseri, Carmelo; Inguanta, Rosalinda

2016-07-01

In this work, brushite and brushite/hydroxyapatite (BS, CaHPO4·H2O; HA, Ca10(PO4)6(OH)2) coatings were deposited on 316L stainless steel (316LSS) from a solution containing Ca(NO3)2·4H2O and NH4H2PO4 by a displacement reaction based on a galvanic contact, where zinc acts as sacrificial anode. Driving force for the cementation reaction arises from the difference in the electrochemical standard potentials of two different metallic materials (316LSS and Zn) immersed in an electrolyte, so forming a galvanic contact leading to the deposition of BS/HA on nobler metal. We found that temperature and deposition time affect coating features (morphology, structure, and composition). Deposits were characterized by means of several techniques. The morphology was investigated by scanning electron microscopy, the elemental composition was obtained by X-ray energy dispersive spectroscopy, whilst the structure was identified by Raman spectroscopy and X-ray diffraction. BS was deposited at all investigated temperatures covering the 316LSS surface. At low and moderate temperature, BS coatings were compact, uniform and with good crystalline degree. On BS layers, HA crystals were obtained at 50°C for all deposition times, while at 25°C, its presence was revealed only after long deposition time. Electrochemical studies show remarkable improvement in corrosion resistance. Copyright © 2016 Elsevier B.V. All rights reserved.

Effects of heat input on mechanical properties of metal inert gas welded 1.6 mm thick galvanized steel sheet

NASA Astrophysics Data System (ADS)

Rafiqul, M. I.; Ishak, M.; Rahman, M. M.

2012-09-01

It is usually a lot easier and less expensive to galvanize steel before it is welded into useful products. Galvanizing afterwards is almost impossible. In this research work, Galvanized Steel was welded by using the ER 308L stainless steel filler material. This work was done to find out an alternative way of welding and investigate the effects of heat input on the mechanical properties of butt welded joints of Galvanized Steel. A 13.7 kW maximum capacity MIG welding machine was used to join 1.6 mm thick sheet of galvanized steel with V groove and no gap between mm. Heat inputs was gradually increased from 21.06 to 25.07 joules/mm in this study. The result shows almost macro defects free welding and with increasing heat input the ultimate tensile strength and welding efficiency decrease. The Vickers hardness also decreases at HAZ with increasing heat input and for each individual specimen; hardness was lowest in heat affected zone (HAZ), intermediate in base metal and maximum in welded zone. The fracture for all specimens was in the heat affected zone while testing in the universal testing machine.

Novel Galvanic Nanostructures of Ag and Pd for Efficient Laser Desorption/Ionization of Low Molecular Weight Compounds

NASA Astrophysics Data System (ADS)

Silina, Yuliya E.; Meier, Florian; Nebolsin, Valeriy A.; Koch, Marcus; Volmer, Dietrich A.

2014-05-01

A simple approach for synthesis of palladium and silver nanostructures with readily adjustable morphologies was developed using galvanic electrochemical deposition, for application to surface-assisted laser desorption/ionization (SALDI) of small biological molecules. A range of fatty acids, triglycerides, carbohydrates, and antibiotics were investigated to assess the performance of the new materials. Intense analyte cations were generated from the galvanic surfaces upon UV laser irradiation such as potassium adducts for a film thickness <100 nm (originating from impurities of the electrolyte solution) and Pd and Ag cluster ions for films with a thickness >120 nm. Possible laser desorption/ionization mechanisms of these galvanic structures are discussed. The films exhibited self-organizing abilities and adjustable morphologies by changing electrochemical parameters. They did not require any stabilizing agents and were inexpensive and very easy to produce. SALDI analysis showed that the materials were stable under ambient conditions and analytical results with excellent measurement reproducibility and detection sensitivity similar to MALDI were obtained. Finally, we applied the galvanic surfaces to fast screening of natural oils with minimum sample preparation.

Diamondlike carbon coating as a galvanic corrosion barrier between dental implant abutments and nickel-chromium superstructures.

PubMed

Ozkomur, Ahmet; Erbil, Mehmet; Akova, Tolga

2013-01-01

The objectives of this study were to evaluate the galvanic corrosion behavior between titanium and nickel-chromium (Ni-Cr) alloy, to investigate the effect of diamondlike carbon (DLC) coating over titanium on galvanic corrosion behavior between titanium and Ni-Cr alloy, and to evaluate the effect of DLC coating over titanium abutments on the fit and integrity of prosthetic assemblies by scanning electron microcopy (SEM). Five Ni-Cr and 10 titanium disks with a diameter of 5 mm and thickness of 3 mm were prepared. DLC coating was applied to five titanium disks. Electrode samples were prepared, and open circuit potential measurements, galvanic current measurements over platinum electrodes, and potentiodynamic polarization tests were carried out. For the SEM evaluation, 20 Ni-Cr alloy and 10 gold alloy superstructures were cast and prepared over 30 abutments. DLC coating was applied to 10 of the abutments. Following the fixation of prosthetic assemblies, the samples were embedded in acrylic resin and cross sectioned longitudinally. Internal fit evaluations were carried out through examination of the SEM images. Titanium showed more noble and electrochemically stable properties than Ni-Cr alloy. DLC coating over the cathode electrode served as an insulating film layer over the surface and prevented galvanic coupling. Results of the SEM evaluations indicated that the DLC-coated and titanium abutments showed no statistically significant difference in fit. Hence, no adverse effects on the adaptation of prosthetic components were found with the application of DLC coating over abutment surfaces. DLC coating might serve as a galvanic corrosion barrier between titanium abutments and Ni-Cr superstructures.

Corrosion behaviour and biocorrosion of galvanized steel water distribution systems.

PubMed

Delaunois, F; Tosar, F; Vitry, V

2014-06-01

Galvanized steel tubes are a popular mean for water distribution systems but suffer from corrosion despite their zinc or zinc alloy coatings. First, the quality of hot-dip galvanized (HDG) coatings was studied. Their microstructure, defects, and common types of corrosion were observed. It was shown that many manufactured tubes do not reach European standard (NBN EN 10240), which is the cause of several corrosion problems. The average thickness of zinc layer was found at 41μm against 55μm prescribed by the European standard. However, lack of quality, together with the usual corrosion types known for HDG steel tubes was not sufficient to explain the high corrosion rate (reaching 20μm per year versus 10μm/y for common corrosion types). Electrochemical tests were also performed to understand the corrosion behaviours occurring in galvanized steel tubes. Results have shown that the limiting step was oxygen diffusion, favouring the growth of anaerobic bacteria in steel tubes. EDS analysis was carried out on corroded coatings and has shown the presence of sulphur inside deposits, suggesting the likely bacterial activity. Therefore biocorrosion effects have been investigated. Actually sulphate reducing bacteria (SRB) can reduce sulphate contained in water to hydrogen sulphide (H2S), causing the formation of metal sulphides. Although microbial corrosion is well-known in sea water, it is less investigated in supply water. Thus, an experimental water main was kept in operation for 6months. SRB were detected by BART tests in the test water main. Copyright © 2014 Elsevier B.V. All rights reserved.

Highly selective removal of Zn(II) ion from hot-dip galvanizing pickling waste with amino-functionalized Fe3O4@SiO2 magnetic nano-adsorbent.

PubMed

Bao, Shuangyou; Tang, Lihong; Li, Kai; Ning, Ping; Peng, Jinhui; Guo, Huibin; Zhu, Tingting; Liu, Ye

2016-01-15

Amino-functionalized Fe3O4@SiO2 magnetic nano-adsorbent was used as a novel sorbent to highly selective removal of Zn(II) ion from hot-dip galvanizing pickling waste in the presence of Fe(II). These hot-dip galvanizing pickling waste mainly contain ZnCl2 and FeCl2 in aqueous HCl media. The properties of this magnetic adsorbent were examined by transmission electron microscopy (TEM), powder X-ray diffraction (XRD), infrared spectrometer (FT-IR) and BET surface area measurements. Various factors influencing the adsorption of Zn(II) ion such as initial concentration of metal ions, the amount of adsorbent, pH value of the solutions, the concentration of coexisting iron ion were investigated by batch experiments. The results indicated that the adsorption equilibrium data obeyed the Freundlich model with maximum adsorption capacities for Zn(II) to 169.5mg/g. The maximum adsorption occurred at pH 5±0.1 and Fe(II) interferences had no obvious influence. This work provides a potential and unique technique for zinc ion removal from hot-dip galvanizing pickling waste. Copyright © 2015 Elsevier Inc. All rights reserved.

77 FR 17430 - Galvanized Steel Wire From the People's Republic of China: Final Determination of Sales at Less...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-26

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-975] Galvanized Steel Wire From... wire from the People's Republic of China (``PRC'').\\1\\ On November 29, 2011, the Department published... galvanized steel wire from the PRC is being, or is likely to be, sold in the United States at LTFV, as...

Wavelet-Based Artifact Identification and Separation Technique for EEG Signals during Galvanic Vestibular Stimulation

PubMed Central

Adib, Mani; Cretu, Edmond

2013-01-01

We present a new method for removing artifacts in electroencephalography (EEG) records during Galvanic Vestibular Stimulation (GVS). The main challenge in exploiting GVS is to understand how the stimulus acts as an input to brain. We used EEG to monitor the brain and elicit the GVS reflexes. However, GVS current distribution throughout the scalp generates an artifact on EEG signals. We need to eliminate this artifact to be able to analyze the EEG signals during GVS. We propose a novel method to estimate the contribution of the GVS current in the EEG signals at each electrode by combining time-series regression methods with wavelet decomposition methods. We use wavelet transform to project the recorded EEG signal into various frequency bands and then estimate the GVS current distribution in each frequency band. The proposed method was optimized using simulated signals, and its performance was compared to well-accepted artifact removal methods such as ICA-based methods and adaptive filters. The results show that the proposed method has better performance in removing GVS artifacts, compared to the others. Using the proposed method, a higher signal to artifact ratio of −1.625 dB was achieved, which outperformed other methods such as ICA-based methods, regression methods, and adaptive filters. PMID:23956786

Effect of Human Movement on Galvanic Intra-Body Communication during Single Gait Cycle

NASA Astrophysics Data System (ADS)

Ibrahim, I. W.; Razak, A. H. A.; Ahmad, A.; Salleh, M. K. M.

2015-11-01

Intra-body communication (IBC) is a communication system that uses human body as a signal transmission medium. From previous research, two coupling methods of IBC were concluded which are capacitive coupling and galvanic coupling. This paper investigates the effect of human movement on IBC using the galvanic coupling method. Because the human movement is control by the limb joint, the knee flexion angle during gait cycle was used to examine the influence of human movement on galvanic coupling IBC. The gait cycle is a cycle of people walking that start from one foot touch the ground till that foot touch the ground again. Frequency range from 300 kHz to 200MHz was swept in order to investigate the signal transmission loss and the result was focused on operating frequency 70MHz to 90MHz. Results show that the transmission loss varies when the knee flexion angle increased. The highest loss of signal at frequency range between 70MHz to 90 MHz was 69dB when the knee flexion angle is 50° and the minimum loss was 51dB during the flexion angle is 5°.

Nanoscale surface analysis on second generation advanced high strength steel after hot dip galvanizing.

PubMed

Arndt, M; Duchoslav, J; Preis, K; Samek, L; Stifter, D

2013-09-01

Second generation advanced high strength steel is one promising material of choice for modern automotive structural parts because of its outstanding maximal elongation and tensile strength. Nonetheless there is still a lack of corrosion protection for this material due to the fact that cost efficient hot dip galvanizing cannot be applied. The reason for the insufficient coatability with zinc is found in the segregation of manganese to the surface during annealing and the formation of manganese oxides prior coating. This work analyses the structure and chemical composition of the surface oxides on so called nano-TWIP (twinning induced plasticity) steel on the nanoscopic scale after hot dip galvanizing in a simulator with employed analytical methods comprising scanning Auger electron spectroscopy (SAES), energy dispersive X-ray spectroscopy (EDX), and focused ion beam (FIB) for cross section preparation. By the combination of these methods, it was possible to obtain detailed chemical images serving a better understanding which processes exactly occur on the surface of this novel kind of steel and how to promote in the future for this material system galvanic protection.

Comparison of Galvanic Currents Generated Between Different Combinations of Orthodontic Brackets and Archwires Using Potentiostat: An In Vitro Study.

PubMed

Nayak, Rabindra S; Shafiuddin, Bareera; Pasha, Azam; Vinay, K; Narayan, Anjali; Shetty, Smitha V

2015-07-01

Technological advances in wire selection and bracket design have led to improved treatment efficiency and allowed longer time intervals between appliance adjustments. The wires remain in the mouth for a longer duration and are subjected to electrochemical reactions, mechanical forces of mastication and generalized wear. These cause different types of corrosion. This study was done to compare the galvanic currents generated between different combinations of brackets and archwires commonly used in orthodontic practices. The materials used for the study included different commercially available orthodontic archwires and brackets. The galvanic current generated by individual materials and different combinations of these materials was tested and compared. The orthodontic archwires used were 0.019″ × 0.025″ heat-activated nickel-titanium (3M Unitek), 0.019″ × 0.025″ beta-titanium (3M Unitek) and 0.019″ × 0.025″ stainless steel (3M Unitek). The orthodontic brackets used were 0.022″ MBT laser-cut (Victory Series, 3M Unitek) and metal-injection molded (Leone Company) maxillary central incisor brackets respectively. The ligature wire used for ligation was 0.009″ stainless steel ligature (HP Company). The galvanic current for individual archwires, brackets, and the different bracket-archwire-ligature combinations was measured by using a Potentiostat machine. The data were generated using the Linear Sweep Voltammetry and OriginPro 8.5 Graphing and Data Analysis Softwares. The study was conducted in two phases. Phase I comprised of five groups for open circuit potential (OCP) and galvanic current (I), whereas Phase II comprised of six groups for galvanic current alone. Mean, standard deviation and range were computed for the OCP and galvanic current (I) values obtained. Results were subjected to statistical analysis through ANOVA. In Phase I, higher mean OCP was recorded in stainless steel archwire, followed by beta-titanium archwire, heat-activated nickel

Simple Heat Treatment for Production of Hot-Dip Galvanized Dual Phase Steel Using Si-Al Steels

NASA Astrophysics Data System (ADS)

Equihua-Guillén, F.; García-Lara, A. M.; Muñíz-Valdes, C. R.; Ortíz-Cuellar, J. C.; Camporredondo-Saucedo, J. E.

2014-01-01

This work presents relevant metallurgical considerations to produce galvanized dual phase steels from low cost aluminum-silicon steels which are produced by continuous strip processing. Two steels with different contents of Si and Al were austenized in the two-phase field ferrite + austenite (α + γ) in a fast manner to obtain dual phase steels, suitable for hot-dip galvanizing process, under typical parameters of continuous annealing processing line. Tensile dual phase properties were obtained from specimens cooled from temperature below Ar3, held during 3 min, intermediate cooling at temperature above Ar1 and quenching in Zn bath at 465 °C. The results have shown typical microstructure and tensile properties of galvanized dual phase steels. Finally, the synergistic effect of aluminum, silicon, and residual chromium on martensite start temperature ( M s), critical cooling rate ( C R), volume fraction of martensite, and tensile properties has been studied.

Mineralogy of Galvanic Corrosion By-products in Domestic Drinking Water Pipes

EPA Science Inventory

This study presents the results of a visual and mineralogical characterization of scales developed over long time periods at galvanically coupled lead-brass and lead-copper pipe joints from several different drinking water distribution systems. The long-term exposure aspect of t...

Performance evaluation of corrosion inhibitors and galvanized steel in concrete exposure specimens.

DOT National Transportation Integrated Search

1999-01-01

Corrosion inhibitor admixtures (CIA) and galvanized reinforcing steel (GS) are used for the corrosion protection for reinforced concrete bridges. The results of a 3.5-year evaluation of exposure specimens containing CIA from three different manufactu...

A finite-element simulation of galvanic coupling intra-body communication based on the whole human body.

PubMed

Song, Yong; Zhang, Kai; Hao, Qun; Hu, Lanxin; Wang, Jingwen; Shang, Fuzhou

2012-10-09

Simulation based on the finite-element (FE) method plays an important role in the investigation of intra-body communication (IBC). In this paper, a finite-element model of the whole body model used for the IBC simulation is proposed and verified, while the FE simulation of the galvanic coupling IBC with different signal transmission paths has been achieved. Firstly, a novel finite-element method for modeling the whole human body is proposed, and a FE model of the whole human body used for IBC simulation was developed. Secondly, the simulations of the galvanic coupling IBC with the different signal transmission paths were implemented. Finally, the feasibility of the proposed method was verified by using in vivo measurements within the frequency range of 10 kHz-5 MHz, whereby some important conclusions were deduced. Our results indicate that the proposed method will offer significant advantages in the investigation of the galvanic coupling intra-body communication.

A Finite-Element Simulation of Galvanic Coupling Intra-Body Communication Based on the Whole Human Body

PubMed Central

Song, Yong; Zhang, Kai; Hao, Qun; Hu, Lanxin; Wang, Jingwen; Shang, Fuzhou

2012-01-01

Simulation based on the finite-element (FE) method plays an important role in the investigation of intra-body communication (IBC). In this paper, a finite-element model of the whole body model used for the IBC simulation is proposed and verified, while the FE simulation of the galvanic coupling IBC with different signal transmission paths has been achieved. Firstly, a novel finite-element method for modeling the whole human body is proposed, and a FE model of the whole human body used for IBC simulation was developed. Secondly, the simulations of the galvanic coupling IBC with the different signal transmission paths were implemented. Finally, the feasibility of the proposed method was verified by using in vivo measurements within the frequency range of 10 kHz–5 MHz, whereby some important conclusions were deduced. Our results indicate that the proposed method will offer significant advantages in the investigation of the galvanic coupling intra-body communication. PMID:23202010

Galvanic displacement reaction and rapid thermal annealing in size/shape controlling silver nanoparticles on silicon substrate

NASA Astrophysics Data System (ADS)

Ghosh, Tapas; Satpati, Biswarup

2017-05-01

The effect of the thermal annealing on silver nanoparticles deposited on silicon surface has been studied. The silver nanoparticles have been deposited by the galvanic displacement reaction. Rapid thermal annealing (RTA) has been performed on the Si substrate, containing the silver nanoparticles. The scanning transmission electron microscopy (STEM), energy dispersive X-ray (EDX) spectroscopy and scanning electron microscopy (SEM) study show that the galvanic displacement reaction and subsequent rapid thermal annealing could lead to well separated and spherical shaped larger silver nanoparticles on silicon substrate.

The study of electrochemical cell taught by problem-based learning

NASA Astrophysics Data System (ADS)

Srichaitung, Paisan

2018-01-01

According to the teaching activity of Chemistry, researcher found that students were not able to seek self knowledge even applied knowledge to their everyday life. Therefore, the researcher is interested in creating an activity to have students constructed their knowledge, science process skills, and can apply knowledge in their everyday life. The researcher presented form of teaching activity of electrochemical cell by using problem-based learning for Mathayom five students of Thai Christian School. The teaching activity focused on electron transfer in galvanic cell. In this activity, the researcher assigned students to design the electron transfer in galvanic cell using any solution that could light up the bulb. Then students were separated into a group of two, which were total seven groups. Each group of students searched the information about the electron transfer in galvanic cell from books, internet, or other sources of information. After students received concepts, or knowledge they searched for, Students designed and did the experiment. Finally, the students in each groups had twenty minutes to give a presentation in front of the classroom about the electron transfer in galvanic using any solution to light up the bulb with showing the experiment, and five minutes to answer their classmates' questions. Giving the presentation took four periods with total seven groups. After students finished their presentation, the researcher had students discussed and summarized the teaching activity's main idea of electron transfer in galvanic. Then, researcher observed students' behavior in each group found that 85.7 percentages of total students developed science process skills, and transferred their knowledge through presentation completely. When students done the post test, the researcher found that 92.85 percentages of total students were able to explain the concept of galvanic cell, described the preparation and the selection of experimental equipment. Furthermore

Galvanic coupling of steel and gold alloy lingual brackets with orthodontic wires.

PubMed

Polychronis, Georgios; Al Jabbari, Youssef S; Eliades, Theodore; Zinelis, Spiros

2018-03-06

The aim of this research was to assess galvanic behavior of lingual orthodontic brackets coupled with representative types of orthodontic wires. Three types of lingual brackets: Incognito (INC), In-Ovation L (IOV), and STb (STB) were combined with a stainless steel (SS) and a nickel-titanium (NiTi) orthodontic archwire. All materials were initially investigated by scanning electron microscopy / x-ray energy dispersive spectroscopy (SEM/EDX) while wires were also tested by x-ray diffraction spectroscopy (XRD). All bracket-wire combinations were immersed in acidic 0.1M NaCl 0.1M lactic acid and neutral NaF 0.3% (wt) electrolyte, and the potential differences were continuously recorded for 48 hours. The SEM/EDX analysis revealed that INC is a single-unit bracket made of a high gold (Au) alloy while IOV and STB are two-piece appliances in which the base and wing are made of SS alloys. The SS wire demonstrated austenite and martensite iron phase, while NiTi wire illustrated an intense austenite crystallographic structure with limited martensite. All bracket wire combinations showed potential differences below the threshold of galvanic corrosion (200 mV) except for INC and STB coupled with NiTi wire in NaF media. The electrochemical results indicate that all brackets tested demonstrated galvanic compatibility with SS wire, but fluoride treatment should be used cautiously with NiTi wires coupled with Au and SS brackets.

Counteracting Muscle Atrophy using Galvanic Stimulation of the Vestibular System

NASA Technical Reports Server (NTRS)

Fox, Robert A.; Polyakov, Igor

1999-01-01

The unloading of weight bearing from antigravity muscles during space flight produces significant muscle atrophy and is one of the most serious health problems facing the space program. Various exercise regimens have been developed and used either alone or in combination with pharmacological techniques to ameliorate this atrophy, but no effective countermeasure exists for this problem. The research in this project was conducted to evaluate the potential use of vestibular galvanic stimulation (VGS) to prevent muscle atrophy resulting from unloading of weight bearing from antigravity muscles. This approach was developed based on two concepts related to the process of maintaining the status of the anti-gravity neuromuscular system. These two premises are: (1) The "tone," or bias on spinal motorneurons is affected by vestibular projections that contribute importantly to maintaining muscle health and status. (2) VGS can be used to modify the excitability, or 'tone' of motorneuron of antigravity muscles. Thus, the strategy is to use VGS to modify the gain of vestibular projections to antigravity muscles and thereby change the general status of these muscles.

Research on the Microstructures and Mechanical Properties of Ti Micro-Alloyed Cold Rolled Hot-Dip Galvanizing DP980 Steel

NASA Astrophysics Data System (ADS)

Han, Yun; Kuang, Shuang; Qi, Xiumei; Xie, Chunqian; Liu, Guanghui

Effects of galvanizing simulation parameters on microstructures and mechanical properties of Ti-microalloyed cold rolled hot-dip galvanizing DP980 steel were investigated in this study by optical microscopy (OM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS) and tensile test. Moreover, the precipitation behavior of Ti in the experimental steel was also studied. The results show that, as the heating temperature increases, the tensile strength of experimental galvanizing DP980 steel decreases while the yield ratio and elongation of the steel are enhanced. The microstructures of experimental steels exhibit typical dual phase steel character and the volume fractions of MA islands are almost 30%. In addition, lots of nano-sized TiC precipitates can be found in the ferrite grains.

Whole cell entrapment techniques.

PubMed

Trelles, Jorge A; Rivero, Cintia W

2013-01-01

Microbial whole cells are efficient, ecological, and low-cost catalysts that have been successfully applied in the pharmaceutical, environmental, and alimentary industries, among others. Microorganism immobilization is a good way to carry out the bioprocess under preparative conditions. The main advantages of this methodology lie in their high operational stability, easy upstream separation and bioprocess scale-up feasibility. Cell entrapment is the most widely used technique for whole cell immobilization. This technique-in which the cells are included within a rigid network-is porous enough to allow the diffusion of substrates and products, protects the selected microorganism from the reaction medium, and has high immobilization efficiency (100 % in most cases).

Galvanic Protection Of 2219 Al By Al/Li Powder

NASA Technical Reports Server (NTRS)

Daech, Alfred

1995-01-01

Coatings consisting of aluminum/lithium powders incorporated into acrylic resin found to protect panels of 2219 aluminum from corrosion by salt spray better than coating consisting of 2219 aluminum in same acrylic resin. Exact mechanism by which aluminum/lithium coatings protect against corrosion unknown, although galvanic mechanism suspected. These coatings (instead of chromium) applied to fasteners and bars to provide cathodic protection, both with and without impressed electrical current.

Synthesis and Characterization of Chromate Conversion Coatings on GALVALUME and Galvanized Steel Substrates

NASA Astrophysics Data System (ADS)

Domínguez-Crespo, M. A.; Onofre-Bustamante, E.; Torres-Huerta, A. M.; Rodríguez-Gómez, F. J.; Rodil, S. E.; Flores-Vela, A.

2009-07-01

The morphology, composition, and corrosion performance of chromate conversion coatings (CCCs) formed on GALVALUME (Fe-Al-Zn) and galvanized steel (Fe-Zn) samples have been studied, and different immersion times (0, 10, 30, and 60 seconds) have been compared. The coated surfaces were analyzed using light microscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and electrochemical measurements in a NaCl solution (3 wt pct). The electrochemical measurements were carried out using the polarization resistance, Tafel, and ac impedance methods. A nonuniform growth of the CCCs having a porous morphology and cracks that appear extended to the base metal was observed. The XRD patterns show that the coatings mainly consist of CrO3, Cr2O3, and traces of Cr2O{7/-2}. The electrochemical results show that GALVALUME presents a better behavior than that of the galvanized steel alloys at each dipping time. The SEM micrographs show that the galvanized steel treatments resulted in the formation of a more uniform film, but their protection barrier broke down faster than that of the GALVALUME samples in contact with the aggressive media. The samples that underwent the lowest degree of dissolution were those with a dipping time of 30 seconds. The difference in the corrosion protection given by the two substrate types could be attributed to the structural properties, grain size, composition, and roughness, which affect oxygen diffusion.

Microstructural Study Of Zinc Hot Dip Galvanized Coatings with Titanium Additions In The Zinc Melt

NASA Astrophysics Data System (ADS)

Konidaris, S.; Pistofidis, N.; Vourlias, G.; Pavlidou, E.; Stergiou, A.; Stergioudis, G.; Polychroniadis, E. K.

2007-04-01

Zinc hot-dip galvanizing is a method for protecting iron and steel against corrosion. Galvanizing with pure Zn or Zn with additions like Ni, Al, Pb and Bi has been extensively studied, but there is a lack of scientific information about other additions. The present work examines the effect of a 0.5 wt% Ti addition in the Zn melt. The samples were exposed to accelerated corrosion in a salt spray chamber (SSC). The microstructure and chemical composition of the coatings were determined by Optical Microscopy, XRD and SEM associated with an EDS Analyzer. The results indicate that the coatings have a typical morphology, while Zn-Ti phases were also detected.

Novel Galvanic Corrosion Inhibitors: Synthesis, Characterization, Fabrication and Testing

DTIC Science & Technology

2007-09-30

have attempted to develop methods based on chemical structural modification to prevent galvanically-induced composite corrosion. [9, 10-12] These...of the two metallopolymers 11 and 12 show characteristic MLCT (metal-to-ligand charge transfer) absorption band of tris(bipyridyl)Ru(II) unit at k...showed absorption band at 450 nm and emission band at 325 nm of tris(bipyridyl)Ru(II) units in its respective UV-vis and fluorescence spectra. Very

Vertical Soil Profiling Using a Galvanic Contact Resistivity Scanning Approach

PubMed Central

Pan, Luan; Adamchuk, Viacheslav I.; Prasher, Shiv; Gebbers, Robin; Taylor, Richard S.; Dabas, Michel

2014-01-01

Proximal sensing of soil electromagnetic properties is widely used to map spatial land heterogeneity. The mapping instruments use galvanic contact, capacitive coupling or electromagnetic induction. Regardless of the type of instrument, the geometrical configuration between signal transmitting and receiving elements typically defines the shape of the depth response function. To assess vertical soil profiles, many modern instruments use multiple transmitter-receiver pairs. Alternatively, vertical electrical sounding can be used to measure changes in apparent soil electrical conductivity with depth at a specific location. This paper examines the possibility for the assessment of soil profiles using a dynamic surface galvanic contact resistivity scanning approach, with transmitting and receiving electrodes configured in an equatorial dipole-dipole array. An automated scanner system was developed and tested in agricultural fields with different soil profiles. While operating in the field, the distance between current injecting and measuring pairs of rolling electrodes was varied continuously from 40 to 190 cm. The preliminary evaluation included a comparison of scan results from 20 locations to shallow (less than 1.2 m deep) soil profiles and to a two-layer soil profile model defined using an electromagnetic induction instrument. PMID:25057135

Galvanic Liquid Applied Coating System for Protection of Embedded Steel Surfaces from Corrosion

NASA Technical Reports Server (NTRS)

Curran, Joseph; MacDowell, Louis; Voska, N. (Technical Monitor)

2002-01-01

The corrosion of reinforcing steel in concrete is an insidious problem for the Kennedy Space Center, government agencies, and the general public. Existing corrosion protection systems on the market are costly, complex, and time-consuming to install, require continuous maintenance and monitoring, and require specialized skills for installation. NASA's galvanic liquid-applied coating offers companies the ability to conveniently protect embedded steel rebar surfaces from corrosion. Liquid-applied inorganic galvanic coating contains one ore more of the following metallic particles: magnesium, zinc, or indium and may contain moisture attracting compounds that facilitate the protection process. The coating is applied to the outer surface of reinforced concrete so that electrical current is established between metallic particles and surfaces of embedded steel rebar; and electric (ionic) current is responsible for providing the necessary cathodic protection for embedded rebar surfaces.

On the Processing of Martensitic Steels in Continuous Galvanizing Lines: Part 1

NASA Astrophysics Data System (ADS)

Song, Taejin; Kwak, Jaihyun; de Cooman, B. C.

2012-01-01

Whereas low-carbon (<0.2 mass pct) martensitic grades can be produced easily in continuous annealing processing lines equipped with the required cooling capacity, the thermal cycles in continuous galvanizing lines make it difficult to produce hot-dip Zn or Zn-alloy coated high-strength martensitic grades. This is because of the tempering processes occurring during dipping of the strip in the liquid Zn bath and, in the case of galvannealed sheet steel, the short thermal treatment required to achieve the alloying between the Zn and the steel. These short additional thermal treatments last less than 30 seconds but severely degrade the mechanical properties. Using a combination of internal friction, X-ray diffraction, and transmission electron microscopy, it is shown that the ultrafine-grained lath microstructure allows for a rapid dislocation recovery and carbide formation during the galvanizing processes. In addition, the effective dislocation pinning occurring during the galvannealing process results in strain localization and the suppression of strain hardening.

Torsional Eye Movements Evoked by Unilateral Labyrinthine Galvanic Polarizations in the Squirrel Monkey

NASA Technical Reports Server (NTRS)

Minor, Lloyd B.; Tomko, David L.; Paige, Gary D.

1995-01-01

Electrical stimulation of vestibular-nerve afferents innervating the semicircular canals has been used to identify the extraocular muscles receiving activation or inhibition by individual ampullary nerves. This technique was originally developed by Szentagothai (1950) and led to the description of three neuron reflex arcs that connect each semicircular canal through an interneuron traversing in the region of the medial longitudinal fasciculus to one ipsilateral and one contralateral eye muscle. Selective ampullary nerve stimulation was subsequently used by Cohen and colleagues (Cohen and Suzuki, 1963; Cohen et al., 1964; Suzuki et al., 1964; Cohen et al., 1966) to study movements of the eyes and activation of individual extraocular muscles in response to stimulation of combinations of ampullary nerves. This work led to a description of the now familiar relationships between activation of a semicircular canal ampullary nerves and the anticipated movement in each eye. Disconjugacy of eye movements induced by individual vertical canal stimulation and dependence of the pulling direction of vertical recti and oblique muscles on eye position were also defined in these experiments. Subsequent studies have defined the mechanisms by which externally applied galvanic currents result in a change in vestibular-nerve afferent discharge. The currents appear to act at the spike trigger site. Perilymphatic cathodal currents depolarize the trigger site and lead to excitation whereas anodal currents hyperpolarize and result in inhibition. Afferents innervating all five vestibular endorgans appear to be affected equally by the currents (Goldberg et al., 1984). Irregularly discharging afferents are about 5-10 times more sensitive than regularly discharging ones because of the steeper slope of the former's faster postspike recovery of excitability in encoder sensitivity (Smith and Goldberg, 1986). Response adaptation similar to that noted during acceleration steps is apparent for

Galvanic coupling between D6AC steel, 6061-T6 aluminum, Inconel 718 and graphite-epoxy composite material: Corrosion occurrence and prevention

NASA Technical Reports Server (NTRS)

Danford, M. D.; Higgins, R. H.

1983-01-01

The effects of galvanic coupling between D6AC steel, 6061-T6 aluminum, Inconel 718, and graphite-epoxy composite material (G/E) in 3.5% NaCl were studied. Measurements of corrosion potentials, galvanic currents and corrosion rates of the bare metals using weight-loss methods served to establish the need for corrosion protection in cases where D6AC steel and 6061-T6 aluminum are galvanically coupled to G/E in salt water while Inconel 718 was shown to be compatible with G/E. Six tests were made to study corrosion protective methods for eliminating galvanic corrosion in the cases of D6AC steel and 6061-T6 aluminum coupled to G/E. These results indicate that, when the G/E is completely coated with paint or a paint/polyurethane resin combination, satisfactory protection of the D6AC steel is achieved with either a coat of zinc-rich primer or a primer/topcoat combination. Likewise, satisfactory corrosion protection of the aluminum is achieved by coating it with an epoxy coating system.

Effects of temperature and operation parameters on the galvanic corrosion of Cu coupled to Au in organic solderability preservatives process

NASA Astrophysics Data System (ADS)

Oh, SeKwon; Kim, YoungJun; Jung, KiMin; Kim, JongSoo; Shon, MinYoung; Kwon, HyukSang

2017-03-01

In this work, we quantitatively examined the effects of temperature and operation parameters such as anode (Cu) to cathode (Au) area ratio, stirring speed, and Cu ion concentration on the galvanic corrosion kinetics of Cu coupled to Au (icouple ( Cu-Au)) on print circuit board in organic solderability preservative (OSP) soft etching solution. With the increase of temperature, galvanic corrosion rate (icouple ( Cu-Au) was increased; however, the degree of galvanic corrosion rate (icouple ( Cu-Au) - icorr (Cu)) was decreased owing to the lower activation energy of Cu coupled to Au, than that of Cu alone. With the increase of area ratio (cathode/anode), stirring speed of the system, icouple ( Cu-Au) was increased by the increase of cathodic reaction kinetics. And icouple ( Cu-Au) was decreased by the increase of the Cu-ion concentration in the OSP soft etching solution.

Galvanic Liquid Applied Coating Development for Protection of Steel in Concrete

NASA Technical Reports Server (NTRS)

Curran, Joseph John; Curran, Jerry; MacDowell, Louis

2004-01-01

Corrosion of reinforcing steel in concrete is a major problem affecting NASA facilities at Kennedy Space Center (KSC), other government agencies, and the general public. Problems include damage to KSC launch support structures, transportation and marine infrastructures, as well as building structures. A galvanic liquid applied coating was developed at KSC in order to address this problem. The coating is a non-epoxy metal rich ethyl silicate liquid coating. The coating is applied as a liquid from initial stage to final stage. Preliminary data shows that this coating system exceeds the NACE 100 millivolt shift criterion. The remainder of the paper details the development of the coating system through the following phases: Phase I: Development of multiple formulations of the coating to achieve easy application characteristics, predictable galvanic activity, long-term protection, and minimum environmental impact. Phase II: Improvement of the formulations tested in Phase I including optimization of metallic loading as well as incorporation of humectants for continuous activation. Phase III: Application and testing of improved formulations on the test blocks. Phase IV: Incorporation of the final formulation upgrades onto large instrumented structures (slabs).

Theoretical Investigation of the Interfacial Reactions during Hot-Dip Galvanizing of Steel

NASA Astrophysics Data System (ADS)

Mandal, G. K.; Balasubramaniam, R.; Mehrotra, S. P.

2009-03-01

In the modern galvanizing line, as soon as the steel strip enters the aluminum-containing zinc bath, two reactions occur at the strip and the liquid-zinc alloy interface: (1) iron rapidly dissolves from the strip surface, raising the iron concentration in the liquid phase at the strip-liquid interface; and (2) aluminum forms a stable aluminum-iron intermetallic compound layer at the strip-coating interface due to its greater affinity toward iron. The main objective of this study is to develop a simple and realistic mathematical model for better understanding of the kinetics of galvanizing reactions at the strip and the liquid-zinc alloy interface. In the present study, a model is proposed to simulate the effect of various process parameters on iron dissolution in the bath, as well as, aluminum-rich inhibition layer formation at the substrate-coating interface. The transient-temperature profile of the immersed strip is predicted based on conductive and convective heat-transfer mechanisms. The inhibition-layer thickness at the substrate-coating interface is predicted by assuming the cooling path of the immersed strip consists of a series of isothermal holds of infinitesimal time-step. The influence of galvanizing reaction is assessed by considering nucleation and growth mechanisms at each hold time, which is used to estimate the total effect of the immersion time on the formation mechanism of the inhibition layer. The iron- dissolution model is developed based on well established principles of diffusion taking into consideration the area fraction covered by the intermetallic on the strip surface during formation of the inhibition layer. The model can be effectively used to monitor the dross formation in the bath by optimizing the process parameters. Theoretical predictions are compared with the findings of other researchers. Simulated results are in good agreement with the theoretical and experimental observation carried out by other investigators.

Cell-Detection Technique for Automated Patch Clamping

NASA Technical Reports Server (NTRS)

McDowell, Mark; Gray, Elizabeth

2008-01-01

A unique and customizable machinevision and image-data-processing technique has been developed for use in automated identification of cells that are optimal for patch clamping. [Patch clamping (in which patch electrodes are pressed against cell membranes) is an electrophysiological technique widely applied for the study of ion channels, and of membrane proteins that regulate the flow of ions across the membranes. Patch clamping is used in many biological research fields such as neurobiology, pharmacology, and molecular biology.] While there exist several hardware techniques for automated patch clamping of cells, very few of those techniques incorporate machine vision for locating cells that are ideal subjects for patch clamping. In contrast, the present technique is embodied in a machine-vision algorithm that, in practical application, enables the user to identify good and bad cells for patch clamping in an image captured by a charge-coupled-device (CCD) camera attached to a microscope, within a processing time of one second. Hence, the present technique can save time, thereby increasing efficiency and reducing cost. The present technique involves the utilization of cell-feature metrics to accurately make decisions on the degree to which individual cells are "good" or "bad" candidates for patch clamping. These metrics include position coordinates (x,y) in the image plane, major-axis length, minor-axis length, area, elongation, roundness, smoothness, angle of orientation, and degree of inclusion in the field of view. The present technique does not require any special hardware beyond commercially available, off-the-shelf patch-clamping hardware: A standard patchclamping microscope system with an attached CCD camera, a personal computer with an imagedata- processing board, and some experience in utilizing imagedata- processing software are all that are needed. A cell image is first captured by the microscope CCD camera and image-data-processing board, then the image

On the Processing of Martensitic Steels in Continuous Galvanizing Lines: Part II

NASA Astrophysics Data System (ADS)

Song, Taejin; Kwak, Jaihyun; de Cooman, B. C.

2012-01-01

The conventional continuous hot-dip galvanizing (GI) and galvannealing (GA) processes can be applied to untransformed austenite to produce Zn and Zn-alloy coated low-carbon ultra-high-strength martensitic steel provided specific alloying additions are made. The most suitable austenite decomposition behavior results from the combined addition of boron, Cr, and Mo, which results in a pronounced transformation bay during isothermal transformation. The occurrence of this transformation bay implies a considerable retardation of the austenite decomposition in the temperature range below the bay, which is close to the stages in the continuous galvanizing line (CGL) thermal cycle related to the GI and GA processes. After the GI and GA processes, a small amount of granular bainite, which consists of bainitic ferrite and discrete islands of martensite/austenite (M/A) constituents embedded in martensite matrix, is present in the microstructure. The ultimate tensile strength (UTS) of the steel after the GI and GA cycle was over 1300 MPa, and the stress-strain curve was continuous without any yielding phenomena.

Lemon Cells Revisited--The Lemon-Powered Calculator.

ERIC Educational Resources Information Center

Swartling, Daniel J.; Morgan, Charlotte

1998-01-01

Describes a demonstration of the principles of a voltaic cell using lemon cells to power a calculator and other items. A lemon fortified with a penny and a galvanized nail produces a potential of one volt. (PVD)

Effect of the Type of Surface Treatment and Cement on the Chloride Induced Corrosion of Galvanized Reinforcements

NASA Astrophysics Data System (ADS)

Tittarelli, Francesca; Mobili, Alessandra; Vicerè, Anna Maria; Roventi, Gabriella; Bellezze, Tiziano

2017-10-01

The effect of a new passivation treatment, obtained by immersion of the galvanized reinforcements in a trivalent chromium salts based solution, on the chlorides induced corrosion has been investigated. To investigate also the effect of cement alkalinity on corrosion behaviour of reinforcements, concretes manufactured with three different European cements were compared. The obtained results show that the alternative treatment based on hexavalent chromium-free baths forms effective protection layers on the galvanized rebar surfaces. The higher corrosion rates of zinc coating in concrete manufactured with Portland cement compared to those recorded for bars in concrete manufactured with pozzolanic cement depends strongly on the higher chloride content at the steel concrete interface.

Galvanic high energy cells with molten salt electrolytes

NASA Astrophysics Data System (ADS)

Borger, W.; Kappus, W.; Kunze, D.; Laig-Hoerstebrock, H.; Panesar, H.; Sterr, G.

1981-02-01

Engineering scale LiAl/LiCl Kcl/FeS electrochemical storage cells were developed for electric vehicle propulsion and peak current compensation. More than 300 deep cycles and 50 Whr/kg in 100 Ahr cells and up to 100 deep cycles and more than 80 Whr/kg in 200 Ahr cells were demonstrated. Separator development for LiAl/FeS cells was focused on ceramic powders. The aluminum nitride powder separator is promising for LiAl/FeS cells. The further development of these cells includes the enhancement of energy density and lifetime as well as ceramic powder separators.

A gauged finite-element potential formulation for accurate inductive and galvanic modelling of 3-D electromagnetic problems

NASA Astrophysics Data System (ADS)

Ansari, S. M.; Farquharson, C. G.; MacLachlan, S. P.

2017-07-01

In this paper, a new finite-element solution to the potential formulation of the geophysical electromagnetic (EM) problem that explicitly implements the Coulomb gauge, and that accurately computes the potentials and hence inductive and galvanic components, is proposed. The modelling scheme is based on using unstructured tetrahedral meshes for domain subdivision, which enables both realistic Earth models of complex geometries to be considered and efficient spatially variable refinement of the mesh to be done. For the finite-element discretization edge and nodal elements are used for approximating the vector and scalar potentials respectively. The issue of non-unique, incorrect potentials from the numerical solution of the usual incomplete-gauged potential system is demonstrated for a benchmark model from the literature that uses an electric-type EM source, through investigating the interface continuity conditions for both the normal and tangential components of the potential vectors, and by showing inconsistent results obtained from iterative and direct linear equation solvers. By explicitly introducing the Coulomb gauge condition as an extra equation, and by augmenting the Helmholtz equation with the gradient of a Lagrange multiplier, an explicitly gauged system for the potential formulation is formed. The solution to the discretized form of this system is validated for the above-mentioned example and for another classic example that uses a magnetic EM source. In order to stabilize the iterative solution of the gauged system, a block diagonal pre-conditioning scheme that is based upon the Schur complement of the potential system is used. For all examples, both the iterative and direct solvers produce the same responses for the potentials, demonstrating the uniqueness of the numerical solution for the potentials and fixing the problems with the interface conditions between cells observed for the incomplete-gauged system. These solutions of the gauged system also

Laser-based direct-write techniques for cell printing

PubMed Central

Schiele, Nathan R; Corr, David T; Huang, Yong; Raof, Nurazhani Abdul; Xie, Yubing; Chrisey, Douglas B

2016-01-01

Fabrication of cellular constructs with spatial control of cell location (±5 μm) is essential to the advancement of a wide range of applications including tissue engineering, stem cell and cancer research. Precise cell placement, especially of multiple cell types in co- or multi-cultures and in three dimensions, can enable research possibilities otherwise impossible, such as the cell-by-cell assembly of complex cellular constructs. Laser-based direct writing, a printing technique first utilized in electronics applications, has been adapted to transfer living cells and other biological materials (e.g., enzymes, proteins and bioceramics). Many different cell types have been printed using laser-based direct writing, and this technique offers significant improvements when compared to conventional cell patterning techniques. The predominance of work to date has not been in application of the technique, but rather focused on demonstrating the ability of direct writing to pattern living cells, in a spatially precise manner, while maintaining cellular viability. This paper reviews laser-based additive direct-write techniques for cell printing, and the various cell types successfully laser direct-written that have applications in tissue engineering, stem cell and cancer research are highlighted. A particular focus is paid to process dynamics modeling and process-induced cell injury during laser-based cell direct writing. PMID:20814088

Numerical Analysis of Edge Over Coating and Baffle Effect on Hot-Dip Galvanizing

NASA Astrophysics Data System (ADS)

Bao, Chengren; Kang, Yonglin; Li, Yan

2017-06-01

In hot-dip galvanizing process, air jet wiping control is so crucial to determine the coating thickness and uniformity of the zinc layer on the steel strip. A numerical simulation of gas-jet wiping in hot-dip galvanizing was conducted to minimize the occurrence of edge over coating (EOC). The causes of EOC were identified by contrasting and analyzing the airflow fields on the strip edge with and without a baffle. The factors influencing the airflow field on the strip edge during the change in the gap between the baffle and the strip edge were also analyzed. The effect of the distance between the air knife and the strip was evaluated. Technological parameters with on-site guidance role were obtained by combining them with the actual production to elucidate the role of the baffle in restraining the occurrence of EOC. The uniform distribution of pressure and coating thickness on the strip is achieved when the distance of the baffle from the strip edge is about 0.3 times of the jetting distance.

Ionic conductivity measurement in magnesium aluminate spinel and solid state galvanic cell with magnesium aluminate electrolyte

NASA Astrophysics Data System (ADS)

Lee, Myongjai

This thesis work is about the experimental measurement of electronic and ionic conductivities in the MgAl2O4 spinel at 500˜600°C range and exploring the fundamental origin of solid-state galvanic cell behavior in the cell of Al|MgAl2O4|Mg, Al|MgAl2O 4|C, and Mg|MgAl2O4|C, in which at least one metal electrode in common with the composition of the electrolyte. For the electronic conductivity measurement, we have used the ion-blocking Gold and Carbon electrodes which are inert with both Mg and Al ions to suppress the ionic conduction from the total conduction. DC polarization method was used to measure the conduction through Au|MgAl2O4|Au and C|MgAl2O4|C specimens. The measured electrical conductivity using Au|MgAl2O4|Au and C|MgAl2O4|C specimens showed 10-9.3 ˜ 10-8.4 (O·cm) -1 at 600˜720°C range following the Arrhenius-type relation. These conductivity data are in agreement with reported data obtained from Pt and Ag ion-blocking electrodes deposited on MgAl2O4 specimens. For the ionic conductivity measurement, we have used the non-blocking Al and Mg electrodes for Al and Mg ionic conductivities, respectively. Ionic conductivity measurement of Al and Mg in separate manner has not been reported yet. In both Al|MgAl2O4|Al and Mg|MgAl2O 4|Mg specimens, gradual increase of conduction was observed once at the initial period before it reaches the steady state conduction. By DC method on the range of 580˜650°C, steady state Al ionic conductivity was measured from Al|MgAl2O4|Al specimen showing 10 -7.7 ˜ 10-6.8 (O·cm)-1 with the activation energy of 1.9eV in sigma = sigma0 exp-QRT formula. There was no difference in the conductivity by the change of the atmosphere from 5%H2 + 95%N2 mixed gas to pure Ar gas. So it was confirmed that the oxygen defect chemistry did not play a role. For Mg ionic conductivity Mg|MgAl2O4|Mg specimen was used and the measured conductivity shows 10-6.7 ˜ 10-4.4 (O·cm)-1 at 400˜550°C with the activation energy of 1.44eV at Ar gas

Textbook Error: Short Circuiting on Electrochemical Cell

ERIC Educational Resources Information Center

Bonicamp, Judith M.; Clark, Roy W.

2007-01-01

Short circuiting an electrochemical cell is an unreported but persistent error in the electrochemistry textbooks. It is suggested that diagrams depicting a cell delivering usable current to a load be postponed, the theory of open-circuit galvanic cells is explained, the voltages from the tables of standard reduction potentials is calculated and…

EVALUATING THE POTENTIAL EFFICACY OF AN ANTIMICROBIAL-CONTAINING SEALANT ON DUCT LINER AND GALVANIZED STEEL

EPA Science Inventory

The article gives results of an evaluation of the potential efficacy of an antimicrobial-containing sealant on fibrous-glass duct liner (FGDL) and galvanized steel (GS) as used in heating, ventilating, and air-conditioning (HVAC) systems. HVAC systems become dirty to various degr...

Expectancy, False Galvanic Skin Response Feedback, and Systematic Desensitization in the Modification of Phobic Behavior

ERIC Educational Resources Information Center

Lick, John

1975-01-01

This study compared systematic desensitization and two pseudotherapy manipulations with and without false galvanic skin response feedback after every session suggesting improvement in the modification of intense snake and spider fear. The results indicated no consistent differences between the three treatment groups. (Author)

Framing susceptibility in a risky choice game is altered by galvanic vestibular stimulation.

PubMed

Preuss, Nora; Kalla, Roger; Müri, Rene; Mast, Fred W

2017-06-07

Recent research provides evidence that galvanic vestibular stimulation (GVS) has a modulating effect on somatosensory perception and spatial cognition. However, other vestibular stimulation techniques have induced changes in affective control and decision making. The aim of this study was to investigate the effect of GVS on framing susceptibility in a risky-choice game. The participants were to decide between a safe and a risky option. The safe option was framed either positively or negatively. During the task, the participants were exposed to either left anodal/right cathodal GVS, right anodal/left cathodal GVS, or sham stimulation (control condition). While left anodal/right cathodal GVS activated more right-hemispheric vestibular brain areas, right anodal/left cathodal GVS resulted in more bilateral activation. We observed increased framing susceptibility during left anodal/right cathodal GVS, but no change in framing susceptibility during right anodal/left cathodal GVS. We propose that GVS results in increased reliance on the affect heuristic by means of activation of cortical and subcortical vestibular-emotional brain structures and that this effect is modulated by the lateralization of the vestibular cortex.

Controlled growth of gold nanocrystals on biogenic As-S nanotubes by galvanic displacement

NASA Astrophysics Data System (ADS)

Liu, Fang; Chen, Wilfred; Myung, Nosang V.

2018-02-01

Traditional methods for fabricating nanoscale arrays are usually based on lithographic techniques while alternative new approaches rely on the use of nanoscale templates made of synthetic or biological materials. Here, gold (Au) nanocrystals were grown on the surface of the microbiologically formed As-S nanotubes through the process of galvanic displacement. The size and organization of the synthesized Au nanocrystals were affected by the pH dependent speciation of HAuCl4 precursors as well as the initial ratio of As-S/HAuCl4. We found that as pH increased, the Au nanocrystals grown on As-S nanotubes had smaller sizes but were more likely to assemble in one-dimension along the nanotubes. At a proper initial ratio of As-S/HAuCl4, Au nanotubes were formed at pH 6.0. The mechanism of Au nanostructures formation and the synthesis process at different pHs were proposed. The resulting Au nanoparticle/As-S nanotube and Au nanotube/As-S nanotube hetero-structures may provide important properties to be used for novel nano-electronic devices.

Personal reflections on a galvanizing trail.

PubMed

O'Dell, B L

1998-01-01

This article encompasses my perception of, and experience in, an exciting segment of the trace element era in nutrition research: the role of zinc in the nutrition of animals and humans. Zinc has been a major player on the stage of trace element research, and it has left a trail that galvanized the attention of many researchers, including myself. It is ubiquitous in biological systems, and it plays a multitude of physiologic and biochemical functions. A brief historical overview is followed by a discussion of the contributions the work done in my laboratory has made toward understanding the physiological and biochemical functions of zinc. The effort of 40 years has led to the belief that one of zinc's major roles, and perhaps its first limiting role, is to preserve plasma-membrane function as regards ion channels and signal transduction. Although substantial knowledge has been gained relating to the importance of zinc in nutrition, much remains to be discovered.

Media Research with a Galvanic Skin Response Biosensor: Some Kids Work Up a Sweat!

ERIC Educational Resources Information Center

Clariana, Roy B.

This study considers the galvanic skin response (GSR) of sixth-grade students (n=20) using print, video, and microcomputer segments. Subjects received all three media treatments, in randomized order. Data for analysis consisted of standardized test scores and GSR measures; a moderate positive relationship was shown between cumulative GSR and…

Metallurgical characterization, galvanic corrosion, and ionic release of orthodontic brackets coupled with Ni-Ti archwires.

PubMed

Darabara, Myrsini S; Bourithis, Lefteris I; Zinelis, Spiros; Papadimitriou, George D

2007-04-01

In orthodontics, a combination of metallic alloys is placed into the oral cavity during medical treatment and thus the corrosion resistance and ionic release of these appliances is of vital importance. The aim of this study is to investigate the elemental composition, microstructure, hardness, corrosion properties, and ionic release of commercially available orthodontic brackets and Copper Ni-Ti archwires. Following the assessment of the elemental composition of the orthodontic wire (Copper Ni-Ti) and the six different brackets (Micro Loc, Equilibrium, OptiMESH(XRT), Gemini, Orthos2, and Rematitan), cyclic polarization curves were obtained for each material to estimate the susceptibility of each alloy to pitting corrosion in 1M lactic acid. Galvanic corrosion between the orthodontic wire and each bracket took place in 1M lactic acid for 28 days at 37 degrees C and then the ionic concentration of Nickel and Chromium was studied. The orthodontic wire is made up from a Ni-Ti alloy with copper additions, while the orthodontic brackets are manufactured by different stainless steel grades or titanium alloys. All tested wires and brackets with the exception of Gemini are not susceptible to pitting corrosion. In galvanic corrosion, following exposure for 28 days, the lowest potential difference (approximately 250 mV) appears for the orthodontic wire Copper Ni-Ti and the bracket made up from pure titanium (Rematitan) or from the stainless steel AISI 316 grade (Micro Loc). Following completion of the galvanic corrosion experiments, measurable quantities of chromium and nickel ions were found in the residual lactic acid solution. (c) 2006 Wiley Periodicals, Inc.

Part I. Corrosion studies of continuous alumina fiber reinforced aluminum-matrix composites. Part II. Galvanic corrosion between continuous alumina fiber reinforced aluminum-matrix composites and 4340 steel

NASA Astrophysics Data System (ADS)

Zhu, Jun

Part I. The corrosion performance of continuous alumina fiber reinforced aluminum-matrix composites (CF-AMCs) was investigated in both the laboratory and field environments by comparing them with their respective monolithic matrix alloys, i.e., pure Al, A1-2wt%Cu T6, and Al 6061 T6. The corrosion initiation sites were identified by monitoring the changes in the surface morphology. Corrosion current densities and pH profiles at localized corrosion sites were measured using the scanning-vibrating electrode technique and the scanning ion-selective electrode technique, respectively. The corrosion damage of the materials immersed in various electrolytes, as well as those exposed in a humidity chamber and outdoor environments, was evaluated. Potentiodynamic polarization behavior was also studied. The corrosion initiation for the composites in 3.15 wt% NaCl occurred primarily around the Fe-rich intermetallic particles, which preferentially existed around the fiber/matrix interface on the composites. The corrosion initiation sites were also caused by physical damage (e.g., localized deformation) to the composite surface. At localized corrosion sites, the buildup of acidity was enhanced by the formation of micro-crevices resulting from fibers left in relief as the matrix corroded. The composites that were tested in exposure experiments exhibited higher corrosion rates than their monolithic alloys. The composites and their monolithic alloys were subjected to pitting corrosion when anodically polarized in the 3.15 wt% NaCl, while they passivated when anodically polarized in 0.5 M Na2SO4. The experimental results indicated that the composites exhibited inferior corrosion resistance compared to their monolithic matrix alloys. Part II. Galvanic corrosion studies were conducted on CF-AMCs coupled to 4340 steel since CF-AMCs have low density and excellent mechanical properties and are being considered as potential jacketing materials for reinforcing steel gun barrels. Coupled and

Alexander von Humboldt: galvanism, animal electricity, and self-experimentation part 2: the electric eel, animal electricity, and later years.

PubMed

Finger, Stanley; Piccolino, Marco; Stahnisch, Frank W

2013-01-01

After extensive experimentation during the 1790s, Alexander von Humboldt remained skeptical about "animal electricity" (and metallic electricity), writing instead about an ill-defined galvanic force. With his worldview and wishing to learn more, he studied electric eels in South America just as the new century began, again using his body as a scientific instrument in many of his experiments. As had been the case in the past and for many of the same reasons, some of his findings with the electric eel (and soon after, Italian torpedoes) seemed to argue against biological electricity. But he no longer used galvanic terminology when describing his electric fish experiments. The fact that he now wrote about animal electricity rather than a different "galvanic" force owed much to Alessandro Volta, who had come forth with his "pile" (battery) for multipling the physical and perceptable effects of otherwise weak electricity in 1800, while Humboldt was deep in South America. Humboldt probably read about and saw voltaic batteries in the United States in 1804, but the time he spent with Volta in 1805 was probably more significant in his conversion from a galvanic to an electrical framework for understanding nerve and muscle physiology. Although he did not continue his animal electricity research program after this time, Humboldt retained his worldview of a unified nature and continued to believe in intrinsic animal electricity. He also served as a patron to some of the most important figures in the new field of electrophysiology (e.g., Hermann Helmholtz and Emil du Bois-Reymond), helping to take the research that he had participated in to the next level.

Isolation of a sulfide-producing bacterial consortium from cooling-tower water: Evaluation of corrosive effects on galvanized steel.

PubMed

Ilhan-Sungur, Esra; Ozuolmez, Derya; Çotuk, Ayşın; Cansever, Nurhan; Muyzer, Gerard

2017-02-01

Sulfidogenic Clostridia and sulfate reducing bacteria (SRB) often cohabit in nature. The presence of these microorganisms can cause microbially influenced corrosion (MIC) of materials in different ways. To investigate this aspect, bacteria were isolated from cooling tower water and used in corrosion tests of galvanized steel. The identity of the isolates was determined by comparative sequence analysis of PCR-amplified 16S rDNA gene fragments, separated by denaturing gradient gel electrophoresis (DGGE). This analysis showed that, in spite of the isolation process, colonies were not pure and consisted of a mixture of bacteria affiliated with Desulfosporosinus meridiei and Clostridium sp. To evaluate the corrosive effect, galvanized steel coupons were incubated with a mixed culture for 4, 8, 24, 72, 96, 168, 360 and 744 h, along with a control set in sterile culture medium only. The corrosion rate was determined by weight loss, and biofilm formation and corroded surfaces were observed by scanning electron microscopy (SEM). Although the sulfide-producing bacterial consortium led to a slight increase in the corrosion of galvanized steel coupons, when compared to the previous studies it can be said that Clostridium sp. can reduce the corrosive effect of the Desulfosporosinus sp. strain. Copyright © 2016 Elsevier Ltd. All rights reserved.

Aerosol characterization and pulmonary responses in rats after short-term inhalation of fumes generated during resistance spot welding of galvanized steel.

PubMed

Antonini, James M; Afshari, Aliakbar; Meighan, Terence G; McKinney, Walter; Jackson, Mark; Schwegler-Berry, Diane; Burns, Dru A; LeBouf, Ryan F; Chen, Bean T; Shoeb, Mohammad; Zeidler-Erdely, Patti C

2017-01-01

Resistance spot welding is a common process to join metals in the automotive industry. Adhesives are often used as sealers to seams of metals that are joined. Anti-spatter compounds sometimes are sprayed onto metals to be welded to improve the weldability. Spot welding produces complex aerosols composed of metal and volatile compounds (VOCs) which can cause lung disease in workers. Male Sprague-Dawley rats (n = 12/treatment group) were exposed by inhalation to 25 mg/m 3 of aerosol for 4 h/day × 8 days during spot welding of galvanized zinc (Zn)-coated steel in the presence or absence of a glue or anti-spatter spray. Controls were exposed to filtered air. Particle size distribution and chemical composition of the generated aerosol were determined. At 1 and 7 days after exposure, bronchoalveolar lavage (BAL) was performed to assess lung toxicity. The generated particles mostly were in the submicron size range with a significant number of nanometer-sized particles formed. The primary metals present in the fumes were Fe (72.5%) and Zn (26.3%). The addition of the anti-spatter spray and glue did affect particle size distribution when spot welding galvanized steel, whereas they had no effect on metal composition. Multiple VOCs (e.g., methyl methacrylate, acetaldehyde, ethanol, acetone, benzene, xylene) were identified when spot welding using either the glue or the anti-spatter spray that were not present when welding alone. Markers of lung injury (BAL lactate dehydrogenase) and inflammation (total BAL cells/neutrophils and cytokines/chemokines) were significantly elevated compared to controls 1 day after exposure to the spot welding fumes. The elevated pulmonary response was transient as lung toxicity mostly returned to control values by 7 days. The VOCs or the concentrations that they were generated during the animal exposures had no measurable effect on the pulmonary responses. Inhalation of galvanized spot welding fumes caused acute lung toxicity most

Morphology and antimony segregation of spangles on batch hot-dip galvanized coatings

NASA Astrophysics Data System (ADS)

Peng, Shu; Lu, Jintang; Che, Chunshan; Kong, Gang; Xu, Qiaoyu

2010-06-01

Spangles produced by batch hot-dip galvanizing process have a rougher surface and a greater surface segregation of alloying element compared with those in continuous hot-dip galvanizing line (CGL), owing to the cooling rate of the former is much smaller than that of the later. Therefore, typical spangles on a batch hot-dipped Zn-0.05Al-0.2Sb alloy coating were investigated. The chemical, morphological characterization and identification of the phases on the spangles were examined by scanning electron microscopy (SEM), backscattered electron imaging (BSE), atomic force microscopy (AFM), energy dispersive spectroscopy (EDS) and X-ray diffraction analysis (XRD). The results showed that the coating surface usually exhibited three kinds of spangles: shiny, feathery and dull spangle, of which extensively antimony surface segregation was detected. The nature of precipitate on the coating surface was identified as β-Sb 3Zn 4, The precipitated β-Sb 3Zn 4 particles distributed randomly on the shiny spangle surface, both β-Sb 3Zn 4 particles and dentritic segregation of antimony dispersed in the dendritic secondary arm spacings of the feathery spangle and on the whole dull spangle surface. The dentritic segregation of antimony and precipitation of Sb 3Zn 4 compound are discussed by a proposed model.

Effect of Process Parameters on the Structure and Properties of Galvanized Sheets

NASA Astrophysics Data System (ADS)

Shukla, S. K.; Saha, B. B.; Triathi, B. D.; Avtar, Ram

2010-07-01

The effect of galvanizing parameters on the structure (spangle size and coating microstructure) and properties (formability and corrosion resistance) of galvanized sheets was studied in a hot dip process simulator (HDPS) in a conventional Pb bearing (0.08-0.10%) zinc bath by varying zinc bath Al level (0.10-0.28%), bath temperature (718-743 K), dipping time (1.5-3.5 s), wiping gas flow rate (200-450 lpm), nozzle distance (15-17 mm) and wiping delay time (0.1-2.1 s). Al level in the range of 0.18-0.24% in combination with dipping time of 1.5-2.5 s and bath temperature of 718-733 K results in superior formability ( E cv: ~9.3 mm) of the composite (thickness: 0.8 mm). High post-dip cooling rates (~25 K/s) suppress spangle growth (spangle size: ~2 mm). The spangle size of the GI sheet strongly influences the corrosion rate which increases from 5.8 to 9.2 mpy with a decrease in spangle size from 17.5 to 3 mm. By controlling the Al level (0.20%) in zinc bath and bath temperature (733 K), the corrosion rate of mini-spangle GI sheet can be controlled to a level of 5.5 mpy.

Comparison of galvanic corrosion potential of metal injection molded brackets to that of conventional metal brackets with nickel-titanium and copper nickel-titanium archwire combinations.

PubMed

Varma, D Praveen Kumar; Chidambaram, S; Reddy, K Baburam; Vijay, M; Ravindranath, D; Prasad, M Rajendra

2013-05-01

The aim of the study is to investigate the galvanic corrosion potential of metal injection molding (MIM) brackets to that of conventional brackets under similar in vitro conditions with nickel-titanium and copper nickel-titanium archwires. Twenty-five maxillary premolar MIM stainless steel brackets and 25 conventional stainless steel brackets and archwires, 0.16 inch, each 10 mm length, 25 nickeltitanium wires, 25 copper nickel-titanium wires were used. They were divided into four groups which had five samples each. Combination of MIM bracket with copper nickel-titanium wire, MIM bracket with nickel-titanium wire and conventional stainless steel brackets with copper nickel-titanium wire and conventional stainless steel brackets with nickel-titanium wires which later were suspended in 350 ml of 1 M lactic acid solution media. Galvanic corrosion potential of four groups were analyzed under similar in vitro conditions. Precorrosion and postcorrosion elemental composition of MIM and conventional stainless steel bracket by scanning electron microscope (SEM) with energy dispersive spectroscope (EDS) was done. MIM bracket showed decreased corrosion susceptibility than conventional bracket with copper nickeltitanium wire. Both MIM and conventional bracket showed similar corrosion resistance potential in association with nickel-titanium archwires. It seems that both brackets are more compatible with copper nickel-titanium archwires regarding the decrease in the consequences of galvanic reaction. The EDS analysis showed that the MIM brackets with copper nickel-titanium wires released less metal ions than conventional bracket with copper nickeltitanium wires. MIM brackets showed decreased corrosion susceptibility, copper nickel-titanium archwires are compatible with both the brackets than nickel-titanium archwires. Clinically MIM and conventional brackets behaved more or less similarly in terms of corrosion resistance. In order to decrease the corrosion potential of MIM

Performance of Flow and Heat Transfer in a Hot-Dip Round Coreless Galvanizing Bath

NASA Astrophysics Data System (ADS)

Yue, Qiang; Zhang, Chengbo; Xu, Yong; Zhou, Li; Kong, Hui; Wang, Jia

2017-04-01

Flow field in a coreless hot-dip galvanizing pot was investigated through a water modeling experiment. The corresponding velocity vector was measured using an acoustic Doppler velocimeter. The flow field of molten zinc in the bath was also analyzed. Steel strip velocities from 1.7 to 2.7 m/s were adopted to determine the effect of steel strip velocity on the molten zinc flow in the bath. A large vortex filled the space at the right side of the sink roll, under linear speed from 1.0 to 2.7 m/s and width from 1.0 to 1.3 m of the steel strip, because of the effects of wall and shear stress. The results of the water modeling experiment were compared with those of numerical simulations. In the simulation, Maxwell equations were solved using finite element method to obtain magnetic flux density, electromagnetic force, and Joule heating. The Joule heating rate reached the maximum and minimum values near the side wall and at the core of the bath, respectively, because of the effect of skin and proximity. In an industrial-sized model, the molten zinc flow and temperature fields driven by electromagnetic force and Joule heating in the inductor of a coreless galvanizing bath were numerically simulated. The results indicated that the direction of electromagnetic force concentrated at the center of the galvanizing pot horizontal planes and exerted a pinch effect on molten zinc. Consequently, molten zinc in the pot was stirred by electromagnetic force. Under molten zinc flow and electromagnetic force stirring, the temperature of the molten zinc became homogeneous throughout the bath. This study provides a basis for optimizing electromagnetic fields in coreless induction pot and fine-tuning the design of steel strip parameters.

Physicochemistry, morphology and leachability of selected metals from post-galvanized sewage sludge from screw factory in Łańcut, SE Poland

NASA Astrophysics Data System (ADS)

Galas, Dagmara; Kalembkiewicz, Jan; Sitarz-Palczak, Elżbieta

2016-12-01

Morphology, physicochemical properties, chemical composition of post-galvanized sewage sludge from Screw Factory in Łańcut, leachability and mobility of metals has been analyzed. The analyses with the use of scanning electron microscope with an adapter to perform chemical analysis of microsites (EDS) showed that the material is characterized by a high fragmentation and a predominant number of irregularly shaped grains. The sewage sludge is alkaline with a large loss of ignition (34.6%) and small bulk density (< 1 g/cm3). The EDS analyses evidenced presence of oxygen, silicon, calcium, chromium, iron and zinc in all examined areas, and presence of manganese and copper in selected areas indicating a non-uniform distribution of metals in the sewage sludge. Within one-stage mineralization and FAAS technique a predominant share of calcium, zinc and iron in terms of dry matter was recorded in the sewage sludge. The contents of Co, Cr, Cu, K, Mn, Ni and Pb in sewage sludge are below 1%. Evaluation of mobility and leaching of metals in sewage sludge was carried out by means of two parameters: accumulation coefficient of mobile fractions and leaching level related to the mass solubility of sewage sludge. The results indicate that the short-term or long-term storage of not inactivated post-galvanized sewage sludge can result in release of metals.

CFD study of ejector flow behavior in a blast furnace gas galvanizing plant

NASA Astrophysics Data System (ADS)

Besagni, Giorgio; Mereu, Riccardo; Inzoli, Fabio

2015-02-01

In recent years, there has been a growing interest toward Blast Furnace Gas (BFG) as a low-grade energy source for industrial furnaces. This paper considers the revamping of a galvanic plant furnace converted to BFG from natural gas. In the design of the new system, the ejector on the exhaust line is a critical component. This paper studies the flow behavior of the ejector using a Computational Fluid Dynamics (CFD) analysis. The CFD model is based on a 3D representation of the ejector, using air and exhaust gases as working fluids. This paper is divided in three parts. In the first part, the galvanic plant used as case study is presented and discussed, in the second part the CFD approach is outlined, and in the third part the CFD approach is validated using experimental data and the numerical results are presented and discussed. Different Reynolds-Averaged Navier-Stokes (RANS) turbulence models ( k-ω SST and k-ɛ Realizable) are evaluated in terms of convergence capability and accuracy in predicting the pressure drop along the ejector. Suggestions for future optimization of the system are also provided.

Branched tellurium hollow nanofibers by galvanic displacement reaction and their sensing performance toward nitrogen dioxide.

PubMed

Park, Hosik; Jung, Hyunsung; Zhang, Miluo; Chang, Chong Hyun; Ndifor-Angwafor, N George; Choa, Yongho; Myung, Nosang V

2013-04-07

Electrospinning and galvanic displacement reaction were combined to synthesize ultra-long hollow tellurium (Te) nanofibers with controlled dimensions, morphology and crystallinity by simply tailoring the electrolyte concentration applied. Within different morphologies of nanofibers, the branched Te nanostructure shows the greatest sensing performance towards NO2 at room temperature.

Substrate decomposition in galvanic displacement reaction: Contrast between gold and silver nanoparticle formation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ghosh, Tapas; Satpati, Biswarup, E-mail: biswarup.satpati@saha.ac.in; Kabiraj, D.

We have investigated substrate decomposition during formation of silver and gold nanoparticles in galvanic displacement reaction on germanium surfaces. Silver and gold nanoparticles were synthesized by electroless deposition on sputter coated germanium thin film (∼ 200 nm) grown initially on silicon substrate. The nanoparticles formation and the substrate corrosion were studied using scanning transmission electron microscopy (STEM) and the energy dispersive X-ray (EDX) spectroscopy.

Spherically-clustered porous Au-Ag alloy nanoparticle prepared by partial inhibition of galvanic replacement and its application for efficient multimodal therapy.

PubMed

Jang, Hongje; Min, Dal-Hee

2015-03-24

The polyvinylpyrrolidone (PVP)-coated spherically clustered porous gold-silver alloy nanoparticle (PVP-SPAN) was prepared by low temperature mediated, partially inhibited galvanic replacement reaction followed by silver etching process. The prepared porous nanostructures exhibited excellent photothermal conversion efficiency under irradiation of near-infrared light (NIR) and allowed a high payload of both doxorubicin (Dox) and thiolated dye-labeled oligonucleotide, DNAzyme (FDz). Especially, PVP-SPAN provided 10 times higher loading capacity for oligonucleotide than conventional hollow nanoshells due to increased pore diameter and surface-to-volume ratio. We demonstrated highly efficient chemo-thermo-gene multitherapy based on codelivery of Dox and FDz with NIR-mediated photothermal therapeutic effect using a model system of hepatitis C virus infected human liver cells (Huh7 human hepatocarcinoma cell line containing hepatitis C virus NS3 gene replicon) compared to conventional hollow nanoshells.

Stainless and Galvanized Steel, Hydrophobic Admixture and Flexible Polymer-Cement Coating Compared in Increasing Durability of Reinforced Concrete Structures

NASA Astrophysics Data System (ADS)

Tittarelli, Francesca; Giosuè, Chiara; Mobili, Alessandra

2017-08-01

The use of stainless or galvanized steel reinforcements, a hydrophobic admixture or a flexible polymer-cement coating were compared as methods to improve the corrosion resistance of sound or cracked reinforced concrete specimens exposed to chloride rich solutions. The results show that in full immersion condition, negligible corrosion rates were detected in all cracked specimens, except those treated with the flexible polymer-cement mortar as preventive method against corrosion and the hydrophobic concrete specimens. High corrosion rates were measured in all cracked specimens exposed to wet-dry cycles, except for those reinforced with stainless steel, those treated with the flexible polymer-cement coating as restorative method against reinforcement corrosion and for hydrophobic concrete specimens reinforced with galvanized steel reinforcements.

Robust Platinum-Based Electrocatalysts for Fuel Cell Applications

NASA Astrophysics Data System (ADS)

Coleman, Eric James

Polymer electrolyte fuel cells (PEMFCs) are energy conversion devices that exploit the energetics of the reaction between hydrogen fuel and O 2 to generate electricity with water as the only byproduct. PEMFCs have attracted substantial attention due to their high conversion efficiency, high energy density, and low carbon footprint. However, PEMFC performance is hindered by the high activation barrier and slow reaction rates at the cathode where O2 undergoes an overall 4-electron reduction to water. The most efficient oxygen reduction reaction (ORR) catalyst materials to date are Pt group metals due to their high catalytic activity and stability in a wide range of operating conditions. Before fuel cells can become economically viable, efforts must be taken to decrease Pt content while maintaining a high level of ORR activity. This work describes the design and synthesis of a Pt-Cu electrocatalyst with ORR activity exceeding that of polycrystalline Pt. Production of this novel catalyst is quite simple and begins with synthesis of a porous Cu substrate, formed by etching Al from a Cu-Al alloy. The porous Cu substrate is then coated with a Pt layer via a spontaneous electrochemical process known as galvanic replacement. The Pt layer enhances the ORR activity (as measured by a rotating ring-disk electrode (RRDE)) and acts as a barrier towards corrosion of the Cu understructure. Growth of the Pt layer can be manipulated by time, temperature, concentration of Pt precursor, and convection rate during galvanic replacement. Data from analytical and electrochemical techniques confirm multiple Pt loadings have been achieved via the galvanic replacement process. The boost in ORR activity for the PtCu catalyst was determined to be a result of its lower affinity towards (site-blocking) OH adsorption. A unique catalyst degradation study explains the mechanism of initial catalyst ORR deactivation for both monometallic and bimetallic Pt-based catalysts. Finally, a rigorous and

Electric and magnetic galvanic distortion decomposition of tensor CSAMT data. Application to data from the Buchans Mine (Newfoundland, Canada)

NASA Astrophysics Data System (ADS)

Garcia, Xavier; Boerner, David; Pedersen, Laust B.

2003-09-01

We have developed a Marquardt-Levenberg inversion algorithm incorporating the effects of near-surface galvanic distortion into the electromagnetic (EM) response of a layered earth model. Different tests on synthetic model responses suggest that for the grounded source method, the magnetic distortion does not vanish for low frequencies. Including this effect is important, although to date it has been neglected. We have inverted 10 stations of controlled-source audio-magnetotellurics (CSAMT) data recorded near the Buchans Mine, Newfoundland, Canada. The Buchans Mine was one of the richest massive sulphide deposits in the world, and is situated in a highly resistive volcanogenic environment, substantially modified by thrust faulting. Preliminary work in the area demonstrated that the EM fields observed at adjacent stations show large differences due to the existence of mineralized fracture zones and variable overburden thickness. Our inversion results suggest a three-layered model that is appropriate for the Buchans Mine. The resistivity model correlates with the seismic reflection interpretation that documents the existence of two thrust packages. The distortion parameters obtained from the inversion concur with the synthetic studies that galvanic magnetic distortion is required to interpret the Buchans data since the magnetic component of the galvanic distortion does not vanish at low frequency.

Synthesis of Hollow Gold-Silver Alloyed Nanoparticles: A "Galvanic Replacement" Experiment for Chemistry and Engineering Students

ERIC Educational Resources Information Center

Jenkins, Samir V.; Gohman, Taylor D.; Miller, Emily K.; Chen, Jingyi

2015-01-01

The rapid academic and industrial development of nanotechnology has led to its implementation in laboratory teaching for undergraduate-level chemistry and engineering students. This laboratory experiment introduces the galvanic replacement reaction for synthesis of hollow metal nanoparticles and investigates the optical properties of these…

Charging system with galvanic isolation and multiple operating modes

DOEpatents

Kajouke, Lateef A.; Perisic, Milun; Ransom, Ray M.

2013-01-08

Systems and methods are provided for operating a charging system with galvanic isolation adapted for multiple operating modes. A vehicle charging system comprises a DC interface, an AC interface, a first conversion module coupled to the DC interface, and a second conversion module coupled to the AC interface. An isolation module is coupled between the first conversion module and the second conversion module. The isolation module comprises a transformer and a switching element coupled between the transformer and the second conversion module. The transformer and the switching element are cooperatively configured for a plurality of operating modes, wherein each operating mode of the plurality of operating modes corresponds to a respective turns ratio of the transformer.

Liquid Galvanic Coatings for Protection of Imbedded Metals

NASA Technical Reports Server (NTRS)

MacDowell, Louis G. (Inventor); Curran, Joseph J. (Inventor)

2003-01-01

Coating compositions and methods of their use are described herein for the reduction of corrosion in imbedded metal structures. The coatings are applied as liquids to an external surface of a substrate in which the metal structures are imbedded. The coatings are subsequently allowed to dry. The liquid applied coatings provide galvanic protection to the imbedded metal structures. Continued protection can be maintained with periodic reapplication of the coating compositions, as necessary, to maintain electrical continuity. Because the coatings may be applied using methods similar to standard paints, and because the coatings are applied to external surfaces of the substrates in which the metal structures are imbedded, the corresponding corrosion protection may be easily maintained. The coating compositions are particularly useful in the protection of metal-reinforced concrete.

Effect of 1,2,4-triazole on galvanic corrosion between cobalt and copper in CMP based alkaline slurry

NASA Astrophysics Data System (ADS)

Fu, Lei; Liu, Yuling; Wang, Chenwei; Han, Linan

2018-04-01

Cobalt has become a new type of barrier material with its unique advantages since the copper-interconnects in the great-large scale integrated circuits (GLSI) into 10 nm and below technical nodes, but cobalt and copper have severe galvanic corrosion during chemical–mechanical flattening. The effect of 1,2,4-triazole on Co/Cu galvanic corrosion in alkaline slurry and the control of rate selectivity of copper and cobalt were investigated in this work. The results of electrochemical experiments and polishing experiments had indicated that a certain concentration of 1,2,4-triazole could form a layer of insoluble and dense passive film on the surface of cobalt and copper, which reduced the corrosion potential difference between cobalt and copper. Meantime, the removal rate of cobalt and copper could be effectively controlled according to demand during the CMP process. When the study optimized slurry was composed of 0.5 wt% colloidal silica, 0.1 %vol. hydrogen peroxide, 0.05 wt% FA/O, 345 ppm 1,2,4-triazole, cobalt had higher corrosion potential than copper and the galvanic corrosion could be reduced effectively when the corrosion potential difference between them decreased to 1 mV and the galvanic corrosion current density reached 0.02 nA/cm2. Meanwhile, the removal rate of Co was 62.396 nm/min, the removal rate of Cu was 47.328 nm/min, so that the removal rate ratio of cobalt and copper was 1.32 : 1, which was a good amendment to the dishing pits. The contact potential corrosion of Co/Cu was very weak, which could be better for meeting the requirements of the barrier CMP. Project supported by the Major National Science and Technology Special Projects (No. 2016ZX02301003-004-007), the Natural Science Foundation of Hebei Province, China (No. F2015202267), and the Outstanding Young Science and Technology Innovation Fund of Hebei University of Technology (No. 2015007).

Mammalian Cell Tissue Culture Techniques.

PubMed

Phelan, Katy; May, Kristin M

2016-06-01

Cultured tissues and cells are used extensively in physiological and pharmacological studies. In vitro cultures provide a means of examining cells and tissues without the complex interactions that would be present if the whole organism were studied. A number of special skills are required in order to preserve the structure, function, behavior, and biology of cells in culture. This unit describes the basic skills required to maintain and preserve cell cultures: maintaining aseptic technique, preparing media with the appropriate characteristics, passaging, freezing and storage, recovering frozen stocks, and counting viable cells. © 2016 by John Wiley & Sons, Inc. Copyright © 2016 John Wiley & Sons, Inc.

Clay and DOPA containing polyelectrolyte multilayer film for imparting anticorrosion properties to galvanized steel.

PubMed

Faure, Emilie; Halusiak, Emilie; Farina, Fabrice; Giamblanco, Nicoletta; Motte, Cécile; Poelman, Mireille; Archambeau, Catherine; Van de Weerdt, Cécile; Martial, Joseph; Jérôme, Christine; Duwez, Anne-Sophie; Detrembleur, Christophe

2012-02-07

A facile and green approach is developed to impart remarkable protection against corrosion to galvanized steel. A protecting multilayer film is formed by alternating the deposition of a polycation bearing catechol groups, used as corrosion inhibitors, with clay that induces barrier properties. This coating does not affect the esthetical aspect of the surface and does not release any toxic molecules in the environment.

Serially connected solid oxide fuel cells having monolithic cores

DOEpatents

Herceg, Joseph E.

1987-01-01

A solid oxide fuel cell for electrochemically combining fuel and oxidant for generating galvanic output, wherein the cell core has an array of cell segments electrically serially connected in the flow direction, each segment consisting of electrolyte walls and interconnect that are substantially devoid of any composite inert materials for support. Instead, the core is monolithic, where each electrolyte wall consists of thin layers of cathode and anode materials sandwiching a thin layer of electrolyte material therebetween. Means direct the fuel to the anode-exposed core passageways and means direct the oxidant to the cathode-exposed core passageways; and means also direct the galvanic output to an exterior circuit. Each layer of the electrolyte composite materials is of the order of 0.002-0.01 cm thick; and each layer of the cathode and anode materials is of the order of 0.002-0.05 cm thick. Between 2 and 50 cell segments may be connected in series.

Serially connected solid oxide fuel cells having monolithic cores

DOEpatents

Herceg, J.E.

1985-05-20

Disclosed is a solid oxide fuel cell for electrochemically combining fuel and oxidant for generating galvanic output. The cell core has an array of cell segments electrically serially connected in the flow direction, each segment consisting of electrolyte walls and interconnect that are substantially devoid of any composite inert materials for support. Instead, the core is monolithic, where each electrolyte wall consists of thin layers of cathode and anode materials sandwiching a thin layer of electrolyte material therebetween. Means direct the fuel to the anode-exposed core passageways and means direct the oxidant to the cathode-exposed core passageways; and means also direct the galvanic output to an exterior circuit. Each layer of the electrolyte composite materials is of the order of 0.002 to 0.01 cm thick; and each layer of the cathode and anode materials is of the order of 0.002 to 0.05 cm thick. Between 2 and 50 cell segments may be connected in series.

Effect of Annealing Temperature on Microstructure and Mechanical Properties of Hot-Dip Galvanizing DP600 Steel

NASA Astrophysics Data System (ADS)

Hai-yan, Sun; Zhi-li, Liu; Yang, Xu; Jian-qiang, Shi; Lian-xuan, Wang

Hot-dip galvanizing dual phase steel DP600 steel grade with low Si was produced by steel plant and experiments by simulating galvanizing thermal history. The microstructure was observed and analyzed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The effect of different annealing temperatures on the microstructure and mechanical properties of dual-phase steel was also discussed. The experimental results show that the dual-phase steel possesses excellent strength and elongation that match EN10346 600MPa standards. The microstructure is ferrite and martensite. TEM micrograph shows that white ferrite with black martensite islands inlay with a diameter of around 1um and the content of 14 18%. The volume will expand and phase changing take the form of shear transformation when ferrite converted to martensite. So there are high density dislocations in ferrite crystalline grain near martensite. The martensite content growing will be obvious along with annealing temperature going up. But the tendency will be weak when temperature high.

Galvanic corrosion behaviour of HE 20 / MDN 138 & HE 20 / MDN 250 alloys in natural seawater

NASA Astrophysics Data System (ADS)

Subramanian, G.; Parthiban, G. T.; Muthuraman, K.; Ramakrishna rao, P.

2016-09-01

In view of their excellent mechanical properties, workability and heat treatment characteristics, MDN 138 & MDN 250 have been widely used in missile, rocket and aerospace industries. With light weight and high performance characteristics HE 20 aluminium alloy acts as an important material in defence and aerospace applications. The galvanic corrosion behaviour of the metal combinations HE 20 / MDN 138 and HE 20 / MDN 250, with 1:1 area ratio, has been studied in natural seawater using the open well facility of CECRI's Offshore Platform at Tuticorin for a year. The open circuit potentials of MDN 138, MDN 250 and HE 20 of the individual metal, the mixed potential and galvanic current of the couples HE 20 / MDN 138 and HE 20 / MDN 250 were periodically monitored throughout the study period. The calcareous deposits on MDN 138 and MDN 250 were analysed using XRD. The results of the study reveal that that HE 20 has offered required amount of protection to MDN 138 & MDN 250.

Single-cell epigenomics: techniques and emerging applications.

PubMed

Schwartzman, Omer; Tanay, Amos

2015-12-01

Epigenomics is the study of the physical modifications, associations and conformations of genomic DNA sequences, with the aim of linking these with epigenetic memory, cellular identity and tissue-specific functions. While current techniques in the field are characterizing the average epigenomic features across large cell ensembles, the increasing interest in the epigenetics within complex and heterogeneous tissues is driving the development of single-cell epigenomics. We review emerging single-cell methods for capturing DNA methylation, chromatin accessibility, histone modifications, chromosome conformation and replication dynamics. Together, these techniques are rapidly becoming a powerful tool in studies of cellular plasticity and diversity, as seen in stem cells and cancer.

Introducing Mammalian Cell Culture and Cell Viability Techniques in the Undergraduate Biology Laboratory.

PubMed

Bowey-Dellinger, Kristen; Dixon, Luke; Ackerman, Kristin; Vigueira, Cynthia; Suh, Yewseok K; Lyda, Todd; Sapp, Kelli; Grider, Michael; Crater, Dinene; Russell, Travis; Elias, Michael; Coffield, V McNeil; Segarra, Verónica A

2017-01-01

Undergraduate students learn about mammalian cell culture applications in introductory biology courses. However, laboratory modules are rarely designed to provide hands-on experience with mammalian cells or teach cell culture techniques, such as trypsinization and cell counting. Students are more likely to learn about cell culture using bacteria or yeast, as they are typically easier to grow, culture, and manipulate given the equipment, tools, and environment of most undergraduate biology laboratories. In contrast, the utilization of mammalian cells requires a dedicated biological safety cabinet and rigorous antiseptic techniques. For this reason, we have devised a laboratory module and method herein that familiarizes students with common cell culture procedures, without the use of a sterile hood or large cell culture facility. Students design and perform a time-efficient inquiry-based cell viability experiment using HeLa cells and tools that are readily available in an undergraduate biology laboratory. Students will become familiar with common techniques such as trypsinizing cells, cell counting with a hemocytometer, performing serial dilutions, and determining cell viability using trypan blue dye. Additionally, students will work with graphing software to analyze their data and think critically about the mechanism of death on a cellular level. Two different adaptations of this inquiry-based lab are presented-one for non-biology majors and one for biology majors. Overall, these laboratories aim to expose students to mammalian cell culture and basic techniques and help them to conceptualize their application in scientific research.

Battery Cell Voltage Sensing and Balancing Using Addressable Transformers

NASA Technical Reports Server (NTRS)

Davies, Francis

2009-01-01

A document discusses the use of saturating transformers in a matrix arrangement to address individual cells in a high voltage battery. This arrangement is able to monitor and charge individual cells while limiting the complexity of circuitry in the battery. The arrangement has inherent galvanic isolation, low cell leakage currents, and allows a single bad cell in a battery of several hundred cells to be easily spotted.

Cross-Beam Laser Joining of AA 6111 to Galvanized Steel in a Coach Peel Configuration

NASA Astrophysics Data System (ADS)

Yang, Guang; Mohammadpour, Masoud; Yazdian, Nima; Ma, Junjie; Carlson, Blair; Wang, Hui-Ping; Kovacevic, Radovan

2017-06-01

Cross-beam laser joining of aluminum alloy 6111 to hot-dip galvanized steel in the coach-peel configuration was investigated with the addition of AA 4047 filler wire. The filler material was not only brazed onto the galvanized steel but also partially fusion-welded with the aluminum panel. Through adjusting the laser power to 3.4 kW, a desirable wetting and spreading of filler wire on both panel surfaces could be achieved, and the thickness of intermetallic layer in the middle section of the interface between the weld bead and steel was less than 2 μm. To better understand the solid/liquid interfacial reaction at the brazing interface, two rotary Gaussian heat source models were introduced to simulate the temperature distribution in the molten pool by using the finite element method. Joint properties were examined in terms of microstructure and mechanical properties. During the tensile test, the fracture of coupons took place at the aluminum side rather than along the interface between the intermetallic layer and steel panel. No failure occurred during the three-point bending test.

Defect detection and classification of galvanized stamping parts based on fully convolution neural network

NASA Astrophysics Data System (ADS)

Xiao, Zhitao; Leng, Yanyi; Geng, Lei; Xi, Jiangtao

2018-04-01

In this paper, a new convolution neural network method is proposed for the inspection and classification of galvanized stamping parts. Firstly, all workpieces are divided into normal and defective by image processing, and then the defective workpieces extracted from the region of interest (ROI) area are input to the trained fully convolutional networks (FCN). The network utilizes an end-to-end and pixel-to-pixel training convolution network that is currently the most advanced technology in semantic segmentation, predicts result of each pixel. Secondly, we mark the different pixel values of the workpiece, defect and background for the training image, and use the pixel value and the number of pixels to realize the recognition of the defects of the output picture. Finally, the defect area's threshold depended on the needs of the project is set to achieve the specific classification of the workpiece. The experiment results show that the proposed method can successfully achieve defect detection and classification of galvanized stamping parts under ordinary camera and illumination conditions, and its accuracy can reach 99.6%. Moreover, it overcomes the problem of complex image preprocessing and difficult feature extraction and performs better adaptability.

Solar Cell Calibration and Measurement Techniques

NASA Technical Reports Server (NTRS)

Bailey, Sheila; Brinker, Dave; Curtis, Henry; Jenkins, Phillip; Scheiman, Dave

1997-01-01

The increasing complexity of space solar cells and the increasing international markets for both cells and arrays has resulted in workshops jointly sponsored by NASDA, ESA and NASA. These workshops are designed to obtain international agreement on standardized values for the AMO spectrum and constant, recommend laboratory measurement practices and establish a set of protocols for international comparison of laboratory measurements. A working draft of an ISO standard, WDI 5387, 'Requirements for Measurement and Calibration Procedures for Space Solar Cells' was discussed with a focus on the scope of the document, a definition of primary standard cell, and required error analysis for all measurement techniques. Working groups addressed the issues of Air Mass Zero (AMO) solar constant and spectrum, laboratory measurement techniques, and the international round robin methodology. A summary is presented of the current state of each area and the formulation of the ISO document.

Solar Cell Calibration and Measurement Techniques

NASA Technical Reports Server (NTRS)

Bailey, Sheila; Brinker, Dave; Curtis, Henry; Jenkins, Phillip; Scheiman, Dave

2004-01-01

The increasing complexity of space solar cells and the increasing international markets for both cells and arrays has resulted in workshops jointly sponsored by NASDA, ESA and NASA. These workshops are designed to obtain international agreement on standardized values for the AMO spectrum and constant, recommend laboratory measurement practices and establish a set of protocols for international comparison of laboratory measurements. A working draft of an ISO standard, WD15387, "Requirements for Measurement and Calibration Procedures for Space Solar Cells" was discussed with a focus on the scope of the document, a definition of primary standard cell, and required error analysis for all measurement techniques. Working groups addressed the issues of Air Mass Zero (AMO) solar constant and spectrum, laboratory measurement techniques, and te international round robin methodology. A summary is presented of the current state of each area and the formulation of the ISO document.

Vestibular Evoked Myogenic Potential (VEMP) Triggered by Galvanic Vestibular Stimulation (GVS): A Promising Tool to Assess Spinal Cord Function in Schistosomal Myeloradiculopathy.

PubMed

Caporali, Júlia Fonseca de Morais; Utsch Gonçalves, Denise; Labanca, Ludimila; Dornas de Oliveira, Leonardo; Vaz de Melo Trindade, Guilherme; de Almeida Pereira, Thiago; Diniz Cunha, Pedro Henrique; Santos Falci Mourão, Marina; Lambertucci, José Roberto

2016-04-01

Schistosomal myeloradiculopathy (SMR), the most severe and disabling ectopic form of Schistosoma mansoni infection, is caused by embolized ova eliciting local inflammation in the spinal cord and nerve roots. The treatment involves the use of praziquantel and long-term corticotherapy. The assessment of therapeutic response relies on neurological examination. Supplementary electrophysiological exams may improve prediction and monitoring of functional outcome. Vestibular evoked myogenic potential (VEMP) triggered by galvanic vestibular stimulation (GVS) is a simple, safe, low-cost and noninvasive electrophysiological technique that has been used to test the vestibulospinal tract in motor myelopathies. This paper reports the results of VEMP with GVS in patients with SMR. A cross-sectional comparative study enrolled 22 patients with definite SMR and 22 healthy controls that were submitted to clinical, neurological examination and GVS. Galvanic stimulus was applied in the mastoid bones in a transcranial configuration for testing VEMP, which was recorded by electromyography (EMG) in the gastrocnemii muscles. The VEMP variables of interest were blindly measured by two independent examiners. They were the short-latency (SL) and the medium-latency (ML) components of the biphasic EMG wave. VEMP showed the components SL (p = 0.001) and ML (p<0.001) delayed in SMR compared to controls. The delay of SL (p = 0.010) and of ML (p = 0.020) was associated with gait dysfunction. VEMP triggered by GVS identified alterations in patients with SMR and provided additional functional information that justifies its use as a supplementary test in motor myelopathies.

The corrosion behaviour of galvanized steel in cooling tower water containing a biocide and a corrosion inhibitor.

PubMed

Minnoş, Bihter; Ilhan-Sungur, Esra; Çotuk, Ayşın; Güngör, Nihal Doğruöz; Cansever, Nurhan

2013-01-01

The corrosion behaviour of galvanized steel in cooling tower water containing a biocide and a corrosion inhibitor was investigated over a 10-month period in a hotel. Planktonic and sessile numbers of sulphate reducing bacteria (SRB) and heterotrophic bacteria were monitored. The corrosion rate was determined by the weight loss method. The corrosion products were analyzed by energy dispersive X-ray spectroscopy and X-ray diffraction. A mineralized, heterogeneous biofilm was observed on the coupons. Although a biocide and a corrosion inhibitor were regularly added to the cooling water, the results showed that microorganisms, such as SRB in the mixed species biofilm, caused corrosion of galvanized steel. It was observed that Zn layers on the test coupons were completely depleted after 3 months. The Fe concentrations in the biofilm showed significant correlations with the weight loss and carbohydrate concentration (respectively, p < 0.01 and p < 0.01).

Theory of the Spin Galvanic Effect at Oxide Interfaces

NASA Astrophysics Data System (ADS)

Seibold, Götz; Caprara, Sergio; Grilli, Marco; Raimondi, Roberto

2017-12-01

The spin galvanic effect (SGE) describes the conversion of a nonequilibrium spin polarization into a transverse charge current. Recent experiments have demonstrated a large conversion efficiency for the two-dimensional electron gas formed at the interface between two insulating oxides, LaAlO3 and SrTiO3 . Here, we analyze the SGE for oxide interfaces within a three-band model for the Ti t2 g orbitals which displays an interesting variety of effective spin-orbit couplings in the individual bands that contribute differently to the spin-charge conversion. Our analytical approach is supplemented by a numerical treatment where we also investigate the influence of disorder and temperature, which turns out to be crucial to providing an appropriate description of the experimental data.

The Effect of Galvanic Vestibular Stimulation on Postural Response of Down Syndrome Individuals on the Seesaw

ERIC Educational Resources Information Center

Carvalho, R. L.; Almeida, G. L.

2011-01-01

In order to better understand the role of the vestibular system in postural adjustments on unstable surfaces, we analyzed the effects of galvanic vestibular stimulation (GVS) on the pattern of muscle activity and joint displacements (ankle knee and hip) of eight intellectually normal participants (control group--CG) and eight control group…

Magnetic Material Assessment of a Novel Ultra-High Step-Up Converter with Single Semiconductor Switch and Galvanic Isolation for Fuel-Cell Power System.

PubMed

Shen, Chih-Lung; Liou, Heng

2017-11-15

In this paper, a novel step-up converter is proposed, which has the particular features of single semiconductor switch, ultra-high conversion ratio, galvanic isolation, and easy control. Therefore, the proposed converter is suitable for the applications of fuel-cell power system. Coupled inductors and switched capacitors are incorporated in the converter to obtain an ultra-high voltage ratio that is much higher than that of a conventional high step-up converter. Even if the turns ratio of coupled inductor and duty ratio are only to be 1 and 0.5, respectively, the converter can readily achieve a voltage gain of up to 18. Owing to this outstanding performance, it can also be applied to any other low voltage source for voltage boosting. In the power stage, only one active switch is used to handle the converter operation. In addition, the leakage energy of the two couple inductors can be totally recycled without any snubber, which simplifies the control mechanism and improves the conversion efficiency. Magnetic material dominates the conversion performance of the converter. Different types of iron cores are discussed for the possibility to serve as a coupled inductor. A 200 W prototype with 400 V output voltage is built to validate the proposed converter. In measurement, it indicates that the highest efficiency can be up to 94%.

Magnetic Material Assessment of a Novel Ultra-High Step-Up Converter with Single Semiconductor Switch and Galvanic Isolation for Fuel-Cell Power System

PubMed Central

Shen, Chih-Lung; Liou, Heng

2017-01-01

In this paper, a novel step-up converter is proposed, which has the particular features of single semiconductor switch, ultra-high conversion ratio, galvanic isolation, and easy control. Therefore, the proposed converter is suitable for the applications of fuel-cell power system. Coupled inductors and switched capacitors are incorporated in the converter to obtain an ultra-high voltage ratio that is much higher than that of a conventional high step-up converter. Even if the turns ratio of coupled inductor and duty ratio are only to be 1 and 0.5, respectively, the converter can readily achieve a voltage gain of up to 18. Owing to this outstanding performance, it can also be applied to any other low voltage source for voltage boosting. In the power stage, only one active switch is used to handle the converter operation. In addition, the leakage energy of the two couple inductors can be totally recycled without any snubber, which simplifies the control mechanism and improves the conversion efficiency. Magnetic material dominates the conversion performance of the converter. Different types of iron cores are discussed for the possibility to serve as a coupled inductor. A 200 W prototype with 400 V output voltage is built to validate the proposed converter. In measurement, it indicates that the highest efficiency can be up to 94%. PMID:29140282

76 FR 23548 - Galvanized Steel Wire From the People's Republic of China and Mexico: Initiation of Antidumping...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-27

... Wire From the People's Republic of China and Mexico: Initiation of Antidumping Duty Investigations...'') received petitions concerning imports of galvanized steel wire from the PRC and Mexico filed in proper form on behalf of Davis Wire Corporation (``Davis Wire''), Johnstown Wire Technologies, Inc., Mid-South...

The effect of immersion time to low carbon steel hardness and microstructure with hot dip galvanizing coating method

NASA Astrophysics Data System (ADS)

Hakim, A. A.; Rajagukguk, T. O.; Sumardi, S.

2018-01-01

Along with developing necessities of metal materials, these rise demands of quality improvements and material protections especially the mechanical properties of the material. This research used hot dip galvanizing coating method. The objectives of this research were to find out Rockwell hardness (HRb), layer thickness, micro structure and observation with Scanning Electron Microscope (SEM) from result of coating by using Hot Dip Galvanizing coating method with immersion time of 3, 6, 9, and 12 minutes at 460°C. The result shows that Highest Rockwell hardness test (HRb) was at 3 minutes immersion time with 76.012 HRb. Highest thickness result was 217.3 μm at 12 minutes immersion. Microstructure test result showed that coating was formed at eta, zeta, delta and gamma phases, while Scanning Electron Microscope (SEM) showed Fe, Zn, Mn, Si and S elements at the specimens after coating.

An Introductory Undergraduate Course Covering Animal Cell Culture Techniques

ERIC Educational Resources Information Center

Mozdziak, Paul E.; Petitte, James N.; Carson, Susan D.

2004-01-01

Animal cell culture is a core laboratory technique in many molecular biology, developmental biology, and biotechnology laboratories. Cell culture is a relatively old technique that has been sparingly taught at the undergraduate level. The traditional methodology for acquiring cell culture training has been through trial and error, instruction when…

Effect of Steel Galvanization on the Microstructure and Mechanical Performances of Planar Magnetic Pulse Welds of Aluminum and Steel

NASA Astrophysics Data System (ADS)

Avettand-Fènoël, M.-N.; Khalil, C.; Taillard, R.; Racineux, G.

2018-07-01

For the first time, planar joints between pure aluminum and galvanized or uncoated DP450 steel joints have been developed via magnetic pulse welding. Both present a wavy interface. The microstructure of the interfacial zone differs according to the joint. With uncoated steel, the interface is composed of discrete 2.5- µm-thick FeAl3 intermetallic compounds and Fe penetration lamellae, whereas the interface of the pure Al-galvanized steel joint is bilayered and composed of a 10-nm-thick (Al)Zn solid solution and a few micrometers thick aggregate of Al- and Zn-based grains, arranged from the Al side to the Zn coating. Even if the nature of the interfacial zone differs with or without the steel coating, both welds present rather similar maximum tensile forces and ductility in shear lap testing.

Effect of Steel Galvanization on the Microstructure and Mechanical Performances of Planar Magnetic Pulse Welds of Aluminum and Steel

NASA Astrophysics Data System (ADS)

Avettand-Fènoël, M.-N.; Khalil, C.; Taillard, R.; Racineux, G.

2018-05-01

For the first time, planar joints between pure aluminum and galvanized or uncoated DP450 steel joints have been developed via magnetic pulse welding. Both present a wavy interface. The microstructure of the interfacial zone differs according to the joint. With uncoated steel, the interface is composed of discrete 2.5-µm-thick FeAl3 intermetallic compounds and Fe penetration lamellae, whereas the interface of the pure Al-galvanized steel joint is bilayered and composed of a 10-nm-thick (Al)Zn solid solution and a few micrometers thick aggregate of Al- and Zn-based grains, arranged from the Al side to the Zn coating. Even if the nature of the interfacial zone differs with or without the steel coating, both welds present rather similar maximum tensile forces and ductility in shear lap testing.

76 FR 47150 - Galvanized Steel Wire From the People's Republic of China and Mexico: Postponement of Preliminary...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-04

... Wire From the People's Republic of China and Mexico: Postponement of Preliminary Determinations of... wire from the People's Republic of China (PRC) and Mexico. The period of investigation (POI) for the... is January 1, 2010, through December 31, 2010. See Galvanized Steel Wire From the People's Republic...

New experimental techniques for solar cells

NASA Technical Reports Server (NTRS)

Lenk, R.

1993-01-01

Solar cell capacitance has special importance for an array controlled by shunting. Experimental measurements of solar cell capacitance in the past have shown disagreements of orders of magnitude. Correct measurement technique depends on maintaining the excitation voltage less than the thermal voltage. Two different experimental methods are shown to match theory well, and two effective capacitances are defined for quantifying the effect of the solar cell capacitance on the shunting system.

Patterning of colloidal particles in the galvanic microreactor

NASA Astrophysics Data System (ADS)

Jan, Linda

A Cu-Au galvanic microreactor is used to demonstrate the autonomous patterning of two-dimensional colloidal crystals with spatial and orientational order which are adherent to the electrode substrate. The microreactor is comprised of a patterned array of copper and gold microelectrodes in a coplanar arrangement that is immersed in a dilute hydrochloric acid solution in which colloidal polystyrene microspheres are suspended. During the electrochemical dissolution of copper, polystyrene colloids are transported to the copper electrodes. The spatial arrangement of the electrodes determines whether the colloids initiate aggregation at the edges or centers of the copper electrodes. Depending on the microreactor parameters, two-dimensional colloidal crystals can form and adhere to the electrode. This thesis investigates the mechanisms governing the autonomous particle motion, the directed particle trajectory (inner- versus edge-aggregation) as affected by the spatial patterning of the electrodes, and the adherence of the colloidal particles onto the substrate. Using in situ current density measurements, particle velocimetry, and order-of-magnitude arguments, it is shown that particle motion is governed by bulk fluid motion and electrophoresis induced by the electrochemical reactions. Bulk electrolyte flow is most likely driven by electrochemical potential gradients of reaction products formed during the inhomogeneous copper dissolution, particularly due to localized high current density at the electrode junction. Preferential aggregation of the colloidal particles resulting in inner- and edge-aggregation is influenced by changes to the flow pattern in response to difference in current density profiles as affected by the spatial patterning of the electrode. Finally, by determining the onset of particle cementation through particle tracking analysis, and by monitoring the deposition of reaction products through the observation of color changes of the galvanic electrodes in

Tribology and Tool Wear of Hot Dip Galvanized Zinc Magnesium Alloys on Cold Rolled Steel Sheets

NASA Astrophysics Data System (ADS)

Raab, A. E.; Berger, E.; Freudenthaler, J.; Leomann, F.; Walch, C.

2011-05-01

Recently zinc based coatings on cold rolled steel with improved functionality in terms of forming and/or corrosion behaviour have been intensively investigated in the steel industry1,2,3. One of the most promising products are zinc magnesium alloys produced in hot dip galvanizing process. These coatings were already introduced in construction industry a few years ago1. With some modifications the improved properties of the coating are also interesting for automotive industry. In the present work the tribological potential of hot dip galvanized zinc magnesium coatings (HDG/ZM) produced at an industrial line under regular production, was studied in terms of sliding properties, adhesive and abrasive tool wear. First a short introduction into surface morphology of HDG/ZM will be given. For the tribological characterization of the material, which is the main topic of the contribution, different tests were performed on hot dip galvanised zinc magnesium material and results were compared with classic hot dip galvanized zinc coating (HDG/Z). The investigations are mainly based on the strip draw test which allows the determination of the friction coefficient directly by using a constant contact pressure. Deep drawing property was tested by forming model cups. The abrasive tool wear was tested using a standard test for material used in automotive industry. The adhesive tool wear was investigated by characterizing the coating material transferred to the tool in the strip draw test. All performed tests show an improved drawability of HDG/ZM compared to classical HDG/Z reference material. However the most promising difference between HDG/ZM and HDG/Z is that galling was found to be less for HDG/ZM than for HDG/Z. Therefore HDG/ZM is an interesting system not only with respect to corrosion protection but also in terms of tribology and provides clear advantages in formability.

Tribology and Tool Wear of Hot Dip Galvanized Zinc Magnesium Alloys on Cold Rolled Steel Sheets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raab, A. E.; Berger, E.; Freudenthaler, J.

Recently zinc based coatings on cold rolled steel with improved functionality in terms of forming and/or corrosion behaviour have been intensively investigated in the steel industry. One of the most promising products are zinc magnesium alloys produced in hot dip galvanizing process. These coatings were already introduced in construction industry a few years ago. With some modifications the improved properties of the coating are also interesting for automotive industry. In the present work the tribological potential of hot dip galvanized zinc magnesium coatings (HDG/ZM) produced at an industrial line under regular production, was studied in terms of sliding properties, adhesivemore » and abrasive tool wear.First a short introduction into surface morphology of HDG/ZM will be given. For the tribological characterization of the material, which is the main topic of the contribution, different tests were performed on hot dip galvanised zinc magnesium material and results were compared with classic hot dip galvanized zinc coating (HDG/Z). The investigations are mainly based on the strip draw test which allows the determination of the friction coefficient directly by using a constant contact pressure. Deep drawing property was tested by forming model cups. The abrasive tool wear was tested using a standard test for material used in automotive industry. The adhesive tool wear was investigated by characterizing the coating material transferred to the tool in the strip draw test.All performed tests show an improved drawability of HDG/ZM compared to classical HDG/Z reference material. However the most promising difference between HDG/ZM and HDG/Z is that galling was found to be less for HDG/ZM than for HDG/Z. Therefore HDG/ZM is an interesting system not only with respect to corrosion protection but also in terms of tribology and provides clear advantages in formability.« less

Cell culture techniques in honey bee research

USDA-ARS?s Scientific Manuscript database

Cell culture techniques are indispensable in most if not all life science disciplines to date. Wherever cell culture models are lacking scientific development is hampered. Unfortunately this has been and still is the case in honey bee research because permanent honey bee cell lines have not yet been...

Introducing Mammalian Cell Culture and Cell Viability Techniques in the Undergraduate Biology Laboratory †

PubMed Central

Bowey-Dellinger, Kristen; Dixon, Luke; Ackerman, Kristin; Vigueira, Cynthia; Suh, Yewseok K.; Lyda, Todd; Sapp, Kelli; Grider, Michael; Crater, Dinene; Russell, Travis; Elias, Michael; Coffield, V. McNeil; Segarra, Verónica A.

2017-01-01

Undergraduate students learn about mammalian cell culture applications in introductory biology courses. However, laboratory modules are rarely designed to provide hands-on experience with mammalian cells or teach cell culture techniques, such as trypsinization and cell counting. Students are more likely to learn about cell culture using bacteria or yeast, as they are typically easier to grow, culture, and manipulate given the equipment, tools, and environment of most undergraduate biology laboratories. In contrast, the utilization of mammalian cells requires a dedicated biological safety cabinet and rigorous antiseptic techniques. For this reason, we have devised a laboratory module and method herein that familiarizes students with common cell culture procedures, without the use of a sterile hood or large cell culture facility. Students design and perform a time-efficient inquiry-based cell viability experiment using HeLa cells and tools that are readily available in an undergraduate biology laboratory. Students will become familiar with common techniques such as trypsinizing cells, cell counting with a hemocytometer, performing serial dilutions, and determining cell viability using trypan blue dye. Additionally, students will work with graphing software to analyze their data and think critically about the mechanism of death on a cellular level. Two different adaptations of this inquiry-based lab are presented—one for non-biology majors and one for biology majors. Overall, these laboratories aim to expose students to mammalian cell culture and basic techniques and help them to conceptualize their application in scientific research. PMID:28861134

Reducing Agent-Assisted Excessive Galvanic Replacement Mediated Seed-Mediated Synthesis of Porous Gold Nanoplates and Highly Efficient Gene-Thermo Cancer Therapy.

PubMed

Kang, Seounghun; Kang, Kyunglee; Huh, Hyun; Kim, Hyungjun; Chang, Sung-Jin; Park, Tae Jung; Chang, Ki Soo; Min, Dal-Hee; Jang, Hongje

2017-10-11

Porous Au nanoplates (pAuNPs) were manufactured by a reducing agent-assisted galvanic replacement reaction on Ag nanoplates using a seed-mediated synthetic approach. Two core additives, poly(vinylpyrrolidone) and l-ascorbic acid, prevented fragmentation and proceeded secondary growth. By controlling the concentration of the additives and the amount of replacing ion AuCl 4 - , various nanostructures including nanoplates with holes, nanoframes, porous nanoplates, and bumpy nanoparticles with unity and homogeneity were synthesized. The present synthetic method is advantageous, because it can be used to manufacture pAuNPs with ease, robustness, and convenience. The prepared pAuNPs exhibited a highly efficient photothermal conversion effect and cargo loading capacity on exposed surfaces by Au-thiol linkage. By using dual cargo mixed loading of the hepatitis C virus (HCV) targeting gene drug DNAzyme and cell-penetrating peptide TAT onto the surface of the pAuNPs and photothermal conversion-mediated hyperthermic treatment, successful gene-thermo therapy against HCV genomic human hepatocarcinoma cells were demonstrated.

Real-time monitoring of laser welding of galvanized high strength steel in lap joint configuration

NASA Astrophysics Data System (ADS)

Kong, Fanrong; Ma, Junjie; Carlson, Blair; Kovacevic, Radovan

2012-10-01

Two different cases regarding the zinc coating at the lap joint faying surface are selected for studying the influence of zinc vapor on the keyhole dynamics of the weld pool and the final welding quality. One case has the zinc coating fully removed at the faying surface; while the other case retains the zinc coating on the faying surface. It is found that removal of the zinc coating at the faying surface produces a significantly better weld quality as exemplified by a lack of spatters whereas intense spatters are present when the zinc coating is present at the faying surface. Spectroscopy is used to detect the optical spectra emitted from a laser generated plasma plume during the laser welding of galvanized high strength DP980 steel in a lap-joint configuration. A correlation between the electron temperature and defects within the weld bead is identified by using the Boltzmann plot method. The laser weld pool keyhole dynamic behavior affected by a high-pressure zinc vapor generated at the faying surface of galvanized steel lap-joint is monitored in real-time by a high speed charge-coupled device (CCD) camera assisted with a green laser as an illumination source.

Correlation analysis of the variation of weld seam and tensile strength in laser welding of galvanized steel

NASA Astrophysics Data System (ADS)

Sinha, Amit Kumar; Kim, Duck Young; Ceglarek, Darek

2013-10-01

Many advantages of laser welding technology such as high speed and non-contact welding make the use of the technology more attractive in the automotive industry. Many studies have been conducted to search the optimal welding condition experimentally that ensure the joining quality of laser welding that relies both on welding system configuration and welding parameter specification. Both non-destructive and destructive techniques, for example, ultrasonic inspection and tensile test are widely used in practice for estimating the joining quality. Non-destructive techniques are attractive as a rapid quality testing method despite relatively low accuracy. In this paper, we examine the relationship between the variation of weld seam and tensile shear strength in the laser welding of galvanized steel in a lap joint configuration in order to investigate the potential of the variation of weld seam as a joining quality estimator. From the experimental analysis, we identify a trend in between maximum tensile shear strength and the variation of weld seam that clearly supports the fact that laser welded parts having larger variation in the weld seam usually have lower tensile strength. The discovered relationship leads us to conclude that the variation of weld seam can be used as an indirect non-destructive testing method for estimating the tensile strength of the welded parts.

Passive Resonant Bidirectional Converter with Galvanic Barrier

NASA Technical Reports Server (NTRS)

Rosenblad, Nathan S. (Inventor)

2014-01-01

A passive resonant bidirectional converter system that transports energy across a galvanic barrier includes a converter using at least first and second converter sections, each section including a pair of transfer terminals, a center tapped winding; a chopper circuit interconnected between the center tapped winding and one of the transfer terminals; an inductance feed winding interconnected between the other of the transfer terminals and the center tap and a resonant tank circuit including at least the inductance of the center tap winding and the parasitic capacitance of the chopper circuit for operating the converter section at resonance; the center tapped windings of the first and second converter sections being disposed on a first common winding core and the inductance feed windings of the first and second converter sections being disposed on a second common winding core for automatically synchronizing the resonant oscillation of the first and second converter sections and transferring energy between the converter sections until the voltage across the pairs of transfer terminals achieves the turns ratio of the center tapped windings.

Design of PdAg Hollow Nanoflowers through Galvanic Replacement and Their Application for Ethanol Electrooxidation.

PubMed

Bin, Duan; Yang, Beibei; Zhang, Ke; Wang, Caiqin; Wang, Jin; Zhong, Jiatai; Feng, Yue; Guo, Jun; Du, Yukou

2016-11-07

In this study, galvanic replacement provides a simple route for the synthesis of PdAg hollow nanoflower structures by using the Ag-seeds as sacrificial templates in the presence of l-ascorbic acid (reductant) and CTAC (capping agent). Transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and EDS mapping were used to characterize the as-prepared PdAg hollow nanoflower catalysts, where they were alloyed nanoflower structures with hollow interiors. By maneuvering the Pd/Ag ratio, we found that the as-prepared Pd 1 Ag 3 hollow nanoflower catalysts had the optimized performance for catalytic activity toward ethanol oxidation reaction. Moreover, these as-prepared PdAg hollow nanoflower catalysts exhibited noticeably higher electrocatalytic activity as compared to pure Pd and commercial Pd/C catalysts due to the alloyed Ag-Pd composition as well as the hollow nanoflower structures. It is anticipated that this work provides a rational design of other architecturally controlled bimetallic nanocrystals for application in fuel cells. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Larsen, G.

Research conducted in FY17 used photo-electrochemical methods to investigate the potential for radiationenhanced galvanic coupling in tritium-producing burnable absorber rod (TPBAR) materials. Specifically, a laboratory electrochemical cell was coupled with UV light in order to perform electrochemical opencircuit voltage and galvanic current measurements, techniques that have been used successfully in previous studies to replicate galvanic processes in reactor settings. UV irradiation can mimic reactor-like behavior because, similar to both directly and indirectly ionizing radiation, UV photons with energy greater than the band gap of the material will generate free charge carriers (electrons and holes) and can substantially alter the passivatingmore » effect of metal oxides.« less

Tolerance to extended galvanic vestibular stimulation: optimal exposure for astronaut training.

PubMed

Dilda, Valentina; MacDougall, Hamish G; Moore, Steven T

2011-08-01

We have developed an analogue of postflight sensorimotor dysfunction in astronauts using pseudorandom galvanic vestibular stimulation (GVS). To date there has been no study of the effects of extended GVS on human subjects and our aim was to determine optimal exposure for astronaut training based on tolerance to intermittent and continuous galvanic stimulation. There were 60 subjects who were exposed to a total of 10.5 min of intermittent GVS at a peak current of 3.5 mA or 5 mA. A subset of 24 subjects who tolerated the intermittent stimulus were subsequently exposed to 20-min continuous stimulation at 3.5 mA or 5 mA. During intermittent GVS the large majority of subjects (78.3%) reported no or at most mild motion sickness symptoms, 13.3% reported moderate symptoms, and 8.3% experienced severe nausea and requested termination of the stimulus. During 20-min continuous exposure, 83.3% of subjects reported no or at most mild motion sickness symptoms and 16.7% (all in the 5-mA group) experienced severe nausea. Based on these results, we propose two basic modes of GVS application to minimize the incidence of motion sickness: intermittent high (5 mA) amplitude, suited to simulation of intensive operator tasks requiring a high-fidelity analogue of postflight sensorimotor dysfunction such as landing or docking maneuvers; and continuous low (3.5 mA) amplitude stimulation, for longer simulation scenarios such as extra vehicular activity. Our results suggest that neither mode of stimulation would induce motion sickness in the large majority of subjects for up to 20 min exposure.

Basic techniques in mammalian cell tissue culture.

PubMed

Phelan, Katy; May, Kristin M

2015-03-02

Cultured mammalian cells are used extensively in cell biology studies. It requires a number of special skills in order to be able to preserve the structure, function, behavior, and biology of the cells in culture. This unit describes the basic skills required to maintain and preserve cell cultures: maintaining aseptic technique, preparing media with the appropriate characteristics, passaging, freezing and storage, recovering frozen stocks, and counting viable cells. Copyright © 2015 John Wiley & Sons, Inc.

Vestibular Evoked Myogenic Potential (VEMP) Triggered by Galvanic Vestibular Stimulation (GVS): A Promising Tool to Assess Spinal Cord Function in Schistosomal Myeloradiculopathy

PubMed Central

Labanca, Ludimila; Dornas de Oliveira, Leonardo; Vaz de Melo Trindade, Guilherme; de Almeida Pereira, Thiago; Diniz Cunha, Pedro Henrique; Santos Falci Mourão, Marina; Lambertucci, José Roberto

2016-01-01

Background Schistosomal myeloradiculopathy (SMR), the most severe and disabling ectopic form of Schistosoma mansoni infection, is caused by embolized ova eliciting local inflammation in the spinal cord and nerve roots. The treatment involves the use of praziquantel and long-term corticotherapy. The assessment of therapeutic response relies on neurological examination. Supplementary electrophysiological exams may improve prediction and monitoring of functional outcome. Vestibular evoked myogenic potential (VEMP) triggered by galvanic vestibular stimulation (GVS) is a simple, safe, low-cost and noninvasive electrophysiological technique that has been used to test the vestibulospinal tract in motor myelopathies. This paper reports the results of VEMP with GVS in patients with SMR. Methods A cross-sectional comparative study enrolled 22 patients with definite SMR and 22 healthy controls that were submitted to clinical, neurological examination and GVS. Galvanic stimulus was applied in the mastoid bones in a transcranial configuration for testing VEMP, which was recorded by electromyography (EMG) in the gastrocnemii muscles. The VEMP variables of interest were blindly measured by two independent examiners. They were the short-latency (SL) and the medium-latency (ML) components of the biphasic EMG wave. Results VEMP showed the components SL (p = 0.001) and ML (p<0.001) delayed in SMR compared to controls. The delay of SL (p = 0.010) and of ML (p = 0.020) was associated with gait dysfunction. Conclusion VEMP triggered by GVS identified alterations in patients with SMR and provided additional functional information that justifies its use as a supplementary test in motor myelopathies. PMID:27128806

Verticality perception during and after galvanic vestibular stimulation.

PubMed

Volkening, Katharina; Bergmann, Jeannine; Keller, Ingo; Wuehr, Max; Müller, Friedemann; Jahn, Klaus

2014-10-03

The human brain constructs verticality perception by integrating vestibular, somatosensory, and visual information. Here we investigated whether galvanic vestibular stimulation (GVS) has an effect on verticality perception both during and after application, by assessing the subjective verticals (visual, haptic and postural) in healthy subjects at those times. During stimulation the subjective visual vertical and the subjective haptic vertical shifted towards the anode, whereas this shift was reversed towards the cathode in all modalities once stimulation was turned off. Overall, the effects were strongest for the haptic modality. Additional investigation of the time course of GVS-induced changes in the haptic vertical revealed that anodal shifts persisted for the entire 20-min stimulation interval in the majority of subjects. Aftereffects exhibited different types of decay, with a preponderance for an exponential decay. The existence of such reverse effects after stimulation could have implications for GVS-based therapy. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

A Cellular Automaton / Finite Element model for predicting grain texture development in galvanized coatings

NASA Astrophysics Data System (ADS)

Guillemot, G.; Avettand-Fènoël, M.-N.; Iosta, A.; Foct, J.

2011-01-01

Hot-dipping galvanizing process is a widely used and efficient way to protect steel from corrosion. We propose to master the microstructure of zinc grains by investigating the relevant process parameters. In order to improve the texture of this coating, we model grain nucleation and growth processes and simulate the zinc solid phase development. A coupling scheme model has been applied with this aim. This model improves a previous two-dimensional model of the solidification process. It couples a cellular automaton (CA) approach and a finite element (FE) method. CA grid and FE mesh are superimposed on the same domain. The grain development is simulated at the micro-scale based on the CA grid. A nucleation law is defined using a Gaussian probability and a random set of nucleating cells. A crystallographic orientation is defined for each one with a choice of Euler's angle (Ψ,θ,φ). A small growing shape is then associated to each cell in the mushy domain and a dendrite tip kinetics is defined using the model of Kurz [2]. The six directions of basal plane and the two perpendicular directions develop in each mushy cell. During each time step, cell temperature and solid fraction are then determined at micro-scale using the enthalpy conservation relation and variations are reassigned at macro-scale. This coupling scheme model enables to simulate the three-dimensional growing kinetics of the zinc grain in a two-dimensional approach. Grain structure evolutions for various cooling times have been simulated. Final grain structure has been compared to EBSD measurements. We show that the preferentially growth of dendrite arms in the basal plane of zinc grains is correctly predicted. The described coupling scheme model could be applied for simulated other product or manufacturing processes. It constitutes an approach gathering both micro and macro scale models.

Basic Techniques in Mammalian Cell Tissue Culture.

PubMed

Phelan, Katy; May, Kristin M

2016-11-01

Cultured mammalian cells are used extensively in cell biology studies. It requires a number of special skills in order to be able to preserve the structure, function, behavior, and biology of the cells in culture. This unit describes the basic skills required to maintain and preserve cell cultures: maintaining aseptic technique, preparing media with the appropriate characteristics, passaging, freezing and storage, recovering frozen stocks, and counting viable cells. © 2016 by John Wiley & Sons, Inc. Copyright © 2016 John Wiley & Sons, Inc.

Measurement and analysis of channel attenuation characteristics for an implantable galvanic coupling human-body communication.

PubMed

Zhang, Shuang; Pun, Sio Hang; Mak, Peng Un; Qin, Yu-Ping; Liu, Yi-He; Vai, Mang I

2016-11-14

In this study, an experiment was designed to verify the low power consumption of galvanic coupling human-body communication. A silver electrode (silver content: 99%) is placed in a pig leg and a sine wave signal with the power of 0 dBm is input. Compared with radio frequency communication and antenna transmission communication, attenuation is reduced by approximately 10 to 15 dB, so channel characteristics are highly improved.

Microscopic analysis and simulation of check-mark stain on the galvanized steel strip

NASA Astrophysics Data System (ADS)

So, Hongyun; Yoon, Hyun Gi; Chung, Myung Kyoon

2010-11-01

When galvanized steel strip is produced through a continuous hot-dip galvanizing process, the thickness of adhered zinc film is controlled by plane impinging air gas jet referred to as "air-knife system". In such a gas-jet wiping process, stain of check-mark or sag line shape frequently appears. The check-mark defect is caused by non-uniform zinc coating and the oblique patterns such as "W", "V" or "X" on the coated surface. The present paper presents a cause and analysis of the check-mark formation and a numerical simulation of sag lines by using the numerical data produced by Large Eddy Simulation (LES) of the three-dimensional compressible turbulent flow field around the air-knife system. It was found that there is alternating plane-wise vortices near the impinging stagnation region and such alternating vortices move almost periodically to the right and to the left sides on the stagnation line due to the jet flow instability. Meanwhile, in order to simulate the check-mark formation, a novel perturbation model has been developed to predict the variation of coating thickness along the transverse direction. Finally, the three-dimensional zinc coating surface was obtained by the present perturbation model. It was found that the sag line formation is determined by the combination of the instantaneous coating thickness distribution along the transverse direction near the stagnation line and the feed speed of the steel strip.

Selective Oxidation and Reactive Wetting during Galvanizing of a CMnAl TRIP-Assisted Steel

NASA Astrophysics Data System (ADS)

Bellhouse, E. M.; McDermid, J. R.

2011-09-01

A transformation induced plasticity (TRIP)-assisted steel with 0.2 pct C, 1.5 pct Mn, and 1.5 pct Al was successfully galvanized using a thermal cycle previously shown to produce an excellent combination of strength and ductility. The steel surface chemistry and oxide morphology were determined as a function of process atmosphere oxygen partial pressure. For the 220 K (-53 °C) dew point (dp) + 20 pct H2 atmosphere, the oxide morphology was a mixture of films and nodules. For the 243 K (-30 °C) dp + 5 pct H2 atmosphere, nodules of MnO were found primarily at grain boundaries. For the 278 K (+5 °C) dp + 5 pct H2 atmosphere, nodules of metallic Fe were found on the surface as a result of alloy element internal oxidation. The steel surface chemistry and oxide morphology were then related to the reactive wetting behavior during continuous hot dip galvanizing. Good wetting was obtained using the two lower oxygen partial pressure process atmospheres [220 K dp and 243 K dp (-53 °C dp and -30 °C dp)]. An increase in the number of bare spots was observed when using the higher oxygen partial pressure process atmosphere (+5 °C dp) due to the increased thickness of localized oxide films.

The role of surface nonuniformity in controlling the initiation of a galvanic replacement reaction.

PubMed

Cobley, Claire M; Zhang, Qiang; Song, Wilbur; Xia, Younan

2011-06-06

The use of silver nanocrystals--asymmetrically truncated octahedrons and nanobars--characterized by a nonuniform surface as substrates for a galvanic replacement reaction was investigated. As the surfaces of these nanocrystals contain facets with a variety of different areas, shapes, and atomic arrangements, we were able to examine the roles of these parameters in different stages of the galvanic replacement reaction with HAuCl(4) (e.g., pitting, hollowing, pit closing, and pore formation), and thus obtain a deeper understanding of the reaction mechanism than is possible with silver nanocubes. We found that the most important of these parameters was the atomic arrangement, that is, whether the surface was capped by a {100} or {111} facet, and that the area and shape of the facet had essentially no effect on the initiation of the reaction. Interestingly, through the reaction with asymmetrically truncated octahedrons, we were also able to demonstrate that even when pitting occurred over a large area, this region would be sealed through a combination of atomic diffusion and deposition during the intermediate stages of the reaction. Consequently, even if pitting occurred across a large percentage of the nanocrystal surface, it was still possible to maintain the morphology of the template throughout the reaction. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Galvanizing and Galvannealing Behavior of CMnSiCr Dual-Phase Steels

NASA Astrophysics Data System (ADS)

Lin, Ko-Chun; Chu, Peng-Wei; Lin, Chao-Sung; Chen, Hon-Bor

2013-06-01

Alloying elements, such as Mn, Mo, Si, and Cr, are commonly used to enhance the strength of advanced high-strength steels. Those elements also play an important role in the hot-dip galvanizing (GI) and galvannealing (GA) process. In this study, two kinds of CMnSiCr dual-phase steels were galvanized and galvannealed using a hot-dip simulator to investigate the effect of the alloying elements on the microstructure of the GI and GA coatings. The results showed that the dual-phase steels had good galvanizability because no bare spots were observed and the Fe-Zn phases were readily formed at the interface. However, the alloying reaction during the GA process was significantly hindered. XPS analysis showed that external oxidation occurred under an extremely low dew point [213 K to 203 K (-60 °C to -70 °C)] atmosphere during the annealing prior to hot dipping. However, most of the oxides were reduced during the GI process. After the GI process, the Al was present as solid solutes in the Fe-Zn phase, suggesting that the Fe-Zn phase was formed from the transformation of the Fe-Al inhibition alloy. Meanwhile, the solubility of Si in the ζ phase was extremely low. With continued GA reaction, the ζ phase transformed into the δ phase, which contained approximately 1.0 at.pct Si. The Si also diffused into the Zn layer during the GA reaction. Hence, the ζ phase did not homogeneously nucleate at the steel substrate/Zn coating interface, but was found at the area away from the interface. Therefore, the Fe-Zn phases on the CMnSiCr dual-phase steels were relatively non-uniform compared to those on interstitial-free steel.

Corrosion Potential Monitoring for Polymer Composite Wrapping and Galvanic CP System for Reinforced Concrete Marine Piles

DTIC Science & Technology

2010-02-01

deteriorated – Rebar corrosion – Spalling concrete Repair Options • Patching • Polymeric composite wraps • Pre-fabricated composite shell with CP Objective... Corrosion Potential Monitoring for Polymer Composite Wrapping and Galvanic CP System for Reinforced Concrete Marine Piles David Bailey, Richard...Command DoD Corrosion Problem • Piers and wharves – Critical facilities – $14.5M maintenance costs – Reinforced concrete piles • Aged and

How Many Atomic Layers of Zinc Are in a Galvanized Iron Coating? An Experiment for General Chemistry Laboratory

ERIC Educational Resources Information Center

Yang, Shui-Ping

2007-01-01

This article describes an experiment using a novel gasometric assembly to determine the thickness and number of atomic layers of zinc coating on galvanized iron substrates. Students solved this problem through three stages. In the first stage, students were encouraged to find a suitable acidic concentration through the guided-inquiry approach. In…

An Automated Classification Technique for Detecting Defects in Battery Cells

NASA Technical Reports Server (NTRS)

McDowell, Mark; Gray, Elizabeth

2006-01-01

Battery cell defect classification is primarily done manually by a human conducting a visual inspection to determine if the battery cell is acceptable for a particular use or device. Human visual inspection is a time consuming task when compared to an inspection process conducted by a machine vision system. Human inspection is also subject to human error and fatigue over time. We present a machine vision technique that can be used to automatically identify defective sections of battery cells via a morphological feature-based classifier using an adaptive two-dimensional fast Fourier transformation technique. The initial area of interest is automatically classified as either an anode or cathode cell view as well as classified as an acceptable or a defective battery cell. Each battery cell is labeled and cataloged for comparison and analysis. The result is the implementation of an automated machine vision technique that provides a highly repeatable and reproducible method of identifying and quantifying defects in battery cells.

Modeling and Characterization of cMUT-based Devices Applied to Galvanic Isolation

NASA Astrophysics Data System (ADS)

Heller, Jacques; Boulmé, Audren; Alquier, Daniel; Ngo, Sophie; Perroteau, Marie; Certon, Domnique

This paper describes a new way of using cMUT technology: galvanic isolation for power electronics. These devices work like acoustic transformers, except that piezoelectricity is replaced by cMUT technology. Primary and secondary circuits are two cMUT-based transducers respectively layered on each side of a silicon substrate, through which the ultrasonic triggering signal is transmitted. A specific model based on a commercial finite element code was implemented to simulate these devices. A particular attention was paid on the modeling of the cMUT/substrate coupling which is a key feature for the intended application. First experimental results performed for model validation are presented here and discussed.

A High-Temperature Combinatorial Technique for the Thermal Analysis of Materials

DTIC Science & Technology

2008-07-14

the calorimetric cell. The power dissipated in the thermistor is determined experimentally from the current supplied to the thermistor and the...electronics unit operates as a power supply for the PnSC sensors and as a data acquisition (DAQ) system for the input/output signals from each sensor. Both...the power supply and DAQ operations are galvanically isolated to ensure a maximum signal to noise ratio for the acquired signals. The control

Galvanic corrosion of ferritic stainless steels used for dental magnetic attachments in contact with an iron-platinum magnet.

PubMed

Nakamura, Keisuke; Takada, Yukyo; Yoda, Masanobu; Kimura, Kohei; Okuno, Osamu

2008-03-01

This study was an examination of the galvanic corrosion of ferritic stainless steels, namely SUS 444, SUS XM27, and SUS 447J1, in contact with a Fe-Pt magnet. The surface area ratio of each stainless steel to the Fe-Pt magnet was set at 1/1 or 1/10. Galvanic corrosion between the stainless steels and the magnet was evaluated by the amount of released ions and the electrochemical properties in 0.9% NaCl solution. Although each stainless steel showed sufficient corrosion resistance for clinical use, the amount of ions released from each tended to increase when the stainless steel was in contact with the magnet. When the surface area ratio was reduced to 1/10, the amount of Fe ions released from the stainless steels increased significantly more than when there was no contact. Since contact with the magnet which possessed an extremely noble potential created a very corrosive environment for the stainless steels, 447J1 was thus the recommended choice against a corrosion exposure as such.

Review of Thermal Spray Coating Applications in the Steel Industry: Part 2—Zinc Pot Hardware in the Continuous Galvanizing Line

NASA Astrophysics Data System (ADS)

Matthews, S.; James, B.

2010-12-01

This two-part article series reviews the application of thermal spray coating technology in the production of steel and steel sheet products. Part 2 of this article series is dedicated to coating solutions in the continuous galvanizing line. The corrosion mechanisms of Fe- and Co-based bulk materials are briefly reviewed as a basis for the development of thermal spray coating solutions. WC-Co thermal spray coatings are commonly applied to low Al-content galvanizing hardware due to their superior corrosion resistance compared to Fe and Co alloys. The effect of phase degradation, carbon content, and WC grain size are discussed. At high Al concentrations, the properties of WC-Co coatings degrade significantly, leading to the application of oxide-based coatings and corrosion-resistant boride containing coatings. The latest results of testing are summarized, highlighting the critical coating parameters.

Application of wire beam electrode technique to investigate initiation and propagation of rebar corrosion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shi, Wei; Dong, Ze Hua, E-mail: zehua.dong@gmail.com; Kong, De Jie

Multi-electrode technique named as wire beam electrode (WBE) was used to study pitting corrosion of rebar under concrete cover. When WBE embedded mortar sample was immersed in NaCl solution, uneven distributions of galvanic current and open circuit potential (OCP) on the WBE were observed due to the initiation of pitting corrosion. The following oxygen depletion in mortar facilitated the negative shift of the OCP and the smoothing of the current and potential distributions. Wetting–drying cycle experiments showed that corrosion products instead of oxygen in wet mortar specimen sustained the propagation of pitting corrosion due to Fe (III) taking part inmore » cathodic depolarization during oxygen-deficient wet period, which was confirmed by micro-Raman spectroscopy. In addition, new pitting corrosion occurred mainly near the corrosion products, leading to preferentially horizontal propagation of rust layer on the WBE. A localized corrosion factor was further presented to quantify the localised corrosion based on galvanic current maps.« less

An experimental analysis to monitor and manage stress among engineering students using Galvanic Skin Response meter.

PubMed

Joshi, Anurag; Kiran, Ravi; Sah, Ash Narayan

2017-01-01

This paper studies the impact of musical religious songs (hymns) for managing stress of Indian Engineering students through Galvanic Skin Response (GSR). The objective of the paper is to find out, whether listening to hymns is able to reduce the value of GSR. Sample students were selected through initial screening and the students who reported high mental stress during the interview were selected for the main drills. All the readings were taken using a GSR meter. Statistical t-test was used for the purpose of hypothesis testing. The study examines the relation between GSR and stress. The results indicated that listening to hymns had a significant effect on the value of GSR. The results highlight that GSR decreased at t = 300 seconds for the experimental group, who listened to hymns, as compared to control group (not exposed to the same). It is recommended that, this amazingly effortless and yet highly efficient traditional technique of listening to hymns be made a part of student's routine curriculum. The paper aims at spreading awareness of listening to hymns as one of the modes of Stress Management amongst Indian Engineering Students.

Plant cell wall characterization using scanning probe microscopy techniques

PubMed Central

Yarbrough, John M; Himmel, Michael E; Ding, Shi-You

2009-01-01

Lignocellulosic biomass is today considered a promising renewable resource for bioenergy production. A combined chemical and biological process is currently under consideration for the conversion of polysaccharides from plant cell wall materials, mainly cellulose and hemicelluloses, to simple sugars that can be fermented to biofuels. Native plant cellulose forms nanometer-scale microfibrils that are embedded in a polymeric network of hemicelluloses, pectins, and lignins; this explains, in part, the recalcitrance of biomass to deconstruction. The chemical and structural characteristics of these plant cell wall constituents remain largely unknown today. Scanning probe microscopy techniques, particularly atomic force microscopy and its application in characterizing plant cell wall structure, are reviewed here. We also further discuss future developments based on scanning probe microscopy techniques that combine linear and nonlinear optical techniques to characterize plant cell wall nanometer-scale structures, specifically apertureless near-field scanning optical microscopy and coherent anti-Stokes Raman scattering microscopy. PMID:19703302

Label-free SERS study of galvanic replacement reaction on silver nanorod surface and its application to detect trace mercury ion

PubMed Central

Wang, Yaohui; Wen, Guiqing; Ye, Lingling; Liang, Aihui; Jiang, Zhiliang

2016-01-01

It is significant to explore a rapid and highly sensitive galvanic replacement reaction (GRR) surface enhanced Raman scattering (SERS) method for detection of trace mercury ions. This article was reported a new GRR SERS analytical platform for detecting Hg(II) with label-free molecular probe Victoria blue B (VBB). In HAc-NaCl-silver nanorod (AgNR) substrate, the molecular probe VBB exhibited a strong SERS peak at 1609 cm−1. Upon addition of Hg(II), the GRR occurred between the AgNR and Hg(II), and formed a weak SERS activity of Hg2Cl2 that deposited on the AgNR surfaces to decrease the SERS intensity at 1609 cm−1. The decreased SERS intensity was linear to Hg(II) concentration in the range of 1.25–125 nmol/L, with a detection limit of 0.2 nmol/L. The GRR was studied by SERS, transmission electron microscopy and other techniques, and the GRR mechanism was discussed. PMID:26792071

Photothermal technique in cell microscopy studies

NASA Astrophysics Data System (ADS)

Lapotko, Dmitry; Chebot'ko, Igor; Kutchinsky, Georgy; Cherenkevitch, Sergey

1995-01-01

Photothermal (PT) method is applied for a cell imaging and quantitative studies. The techniques for cell monitoring, imaging and cell viability test are developed. The method and experimental set up for optical and PT-image acquisition and analysis is described. Dual- pulsed laser set up combined with phase contrast illumination of a sample provides visualization of temperature field or absorption structure of a sample with spatial resolution 0.5 micrometers . The experimental optics, hardware and software are designed using the modular principle, so the whole set up can be adjusted for various experiments: PT-response monitoring or photothermal spectroscopy studies. Sensitivity of PT-method provides the imaging of the structural elements of live (non-stained) white blood cells. The results of experiments with normal and subnormal blood cells (red blood cells, lymphocytes, neutrophyles and lymphoblasts) are reported. Obtained PT-images are different from optical analogs and deliver additional information about cell structure. The quantitative analysis of images was used for cell population comparative diagnostic. The viability test for red blood cell differentiation is described. During the study of neutrophyles in norma and sarcoidosis disease the differences in PT-images of cells were found.

Cementation of colloidal particles on electrodes in a galvanic microreactor.

PubMed

Jan, Linda; Punckt, Christian; Aksay, Ilhan A

2013-07-10

We have studied the processes leading to the cementation of colloidal particles during their autonomous assembly on corroding copper electrodes within a Cu-Au galvanic microreactor. We determined the onset of particle immobilization through particle tracking, monitored the dissolution of copper as well as the deposition of insoluble products of the corrosion reactions in situ, and showed that particle immobilization initiated after reaction products (RPs) began to deposit on the electrode substrate. We further demonstrated that the time and the extent of RP precipitation and thus the strength of the particle-substrate bond could be tuned by varying the amount of copper in the system and the microreactor pH. The ability to cement colloidal particles at locations undergoing corrosion illustrates that the studied colloidal assembly approach holds potential for applications in dynamic material property adaptation.

Use of Galvanic Skin Responses, Salivary Biomarkers, and Self-reports to Assess Undergraduate Student Performance During a Laboratory Exam Activity

PubMed Central

Villanueva, Idalis; Valladares, Maria; Goodridge, Wade

2016-01-01

Typically, self-reports are used in educational research to assess student response and performance to a classroom activity. Yet, addition of biological and physiological measures such as salivary biomarkers and galvanic skin responses are rarely included, limiting the wealth of information that can be obtained to better understand student performance. A laboratory protocol to study undergraduate students' responses to classroom events (e.g., exams) is presented. Participants were asked to complete a representative exam for their degree. Before and after the laboratory exam session, students completed an academic achievement emotions self-report and an interview that paralleled these questions when participants wore a galvanic skin sensor and salivary biomarkers were collected. Data collected from the three methods resulted in greater depth of information about students' performance when compared to the self-report. The work can expand educational research capabilities through more comprehensive methods for obtaining nearer to real-time student responses to an examination activity. PMID:26891278

Repetitively Coupled Chemical Reduction and Galvanic Exchange as a Synthesis Strategy for Expanding Applicable Number of Pt Atoms in Dendrimer-Encapsulated Pt Nanoparticles.

PubMed

Cho, Taehoon; Yoon, Chang Won; Kim, Joohoon

2018-06-13

In this study, we report the controllable synthesis of dendrimer-encapsulated Pt nanoparticles (Pt DENs) utilizing repetitively coupled chemical reduction and galvanic exchange reactions. The synthesis strategy allows the expansion of the applicable number of Pt atoms encapsulated inside dendrimers to more than 1000 without being limited by the fixed number of complexation sites for Pt 2+ precursor ions in the dendrimers. The synthesis of Pt DENs is achieved in a short period of time (i.e., ∼10 min) simply by the coaddition of appropriate amounts of Cu 2+ and Pt 2+ precursors into aqueous dendrimer solution and subsequent addition of reducing agents such as BH 4 - , resulting in fast and selective complexation of Cu 2+ with the dendrimers and subsequent chemical reduction of the complexed Cu 2+ while uncomplexed Pt 2+ precursors remain oxidized. Interestingly, the chemical reduction of Cu 2+ , leading to the formation of Cu nanoparticles encapsulated inside the dendrimers, is coupled with the galvanic exchange of the Cu nanoparticles with the nearby Pt 2+ . This coupling repetitively proceeds until all of the added Pt 2+ ions form into Pt nanoparticles encapsulated inside the dendrimers. In contrast to the conventional method utilizing direct chemical reduction, this repetitively coupled chemical reduction and galvanic exchange enables a substantial increase in the applicable number of Pt atoms up to 1320 in Pt DENs while maintaining the unique features of DENs.

Characterization of Coatings on Steel Self-Piercing Rivets for Use with Magnesium Alloys

NASA Astrophysics Data System (ADS)

McCune, Robert C.; Forsmark, Joy H.; Upadhyay, Vinod; Battocchi, Dante

Incorporation of magnesium alloys in self-pierce rivet (SPR) joints poses several unique challenges among which are the creation of spurious galvanic cells and aggravated corrosion of adjacent magnesium when coated steel rivets are employed. This work firstly reviews efforts on development of coatings to steel fasteners for the diminution of galvanic corrosion when used with magnesium alloys. Secondly, approaches, based on several electrochemical methods, for the measurement of the galvanic-limiting effect of a number of commercially-available coatings to hardened 10B37 steel self-piercing rivets inserted into alloy couples incorporating several grades of magnesium are reported. Electrochemical impedance spectroscopy (EIS), zero-resistance ammeter (ZRA), corrosion potential and potential-mapping visualization methods (e.g. scanning vibrating electrode technique — SVET) are illustrated for the several rivet coatings considered.

Dye-sensitized solar cells using laser processing techniques

NASA Astrophysics Data System (ADS)

Kim, Heungsoo; Pique, Alberto; Kushto, Gary P.; Auyeung, Raymond C. Y.; Lee, S. H.; Arnold, Craig B.; Kafafi, Zakia H.

2004-07-01

Laser processing techniques, such as laser direct-write (LDW) and laser sintering, have been used to deposit mesoporous nanocrystalline TiO2 (nc-TiO2) films for use in dye-sensitized solar cells. LDW enables the fabrication of conformal structures containing metals, ceramics, polymers and composites on rigid and flexible substrates without the use of masks or additional patterning techniques. The transferred material maintains a porous, high surface area structure that is ideally suited for dye-sensitized solar cells. In this experiment, a pulsed UV laser (355nm) is used to forward transfer a paste of commercial TiO2 nanopowder (P25) onto transparent conducting electrodes on flexible polyethyleneterephthalate (PET) and rigid glass substrates. For the cells based on flexible PET substrates, the transferred TiO2 layers were sintered using an in-situ laser to improve electron paths without damaging PET substrates. In this paper, we demonstrate the use of laser processing techniques to produce nc-TiO2 films (~10 μm thickness) on glass for use in dye-sensitized solar cells (Voc = 690 mV, Jsc = 8.7 mA/cm2, ff = 0.67, η = 4.0 % at 100 mW/cm2). This work was supported by the Office of Naval Research.

Research on Forming Mechanisms and Controlling Measurements for Surface Light Spot Defects of Galvanizing Steel Coils for Automobile Use

NASA Astrophysics Data System (ADS)

Guangmin, Wei; Haiyan, Sun; Jianqiang, Shi; Lianxuan, Wang; Haihong, Wu

When producing high surface quality galvanizing steel coils for automobile use, there are always many light spots on the surface since Hansteel CGL No.1 has been put into operation. The defect samples were analyzed by SEM and EDS. The result shows that cause for light spot is not only one. There are more Mn and P in high strength auto sheet, which can result in difficulty to be cleaned off the oxide on the hot rolled coils, so the defects coming. This is why the defects come with high strength auto sheet. When coils galvanized, the defects can't be covered up. To the contrary, the defects will be more obvious when zinc growing on the surface. And sometimes zinc or residue can adhere to work rolls when strips passing through SPM. The deposits then press normal coating. So the light spots come more. When the defect comes from pressing, there is no defect on steel base. The causation is found and measures were taken including high pressure cleaning equipments adopted. Result shows that the defects disappeared.

Dissolution-Induced Nanowire Synthesis on Hot-Dip Galvanized Surface in Supercritical Carbon Dioxide.

PubMed

Kaleva, Aaretti; Saarimaa, Ville; Heinonen, Saara; Nikkanen, Juha-Pekka; Markkula, Antti; Väisänen, Pasi; Levänen, Erkki

2017-07-11

In this study, we demonstrate a rapid treatment method for producing a needle-like nanowire structure on a hot-dip galvanized sheet at a temperature of 50 °C. The processing method involved only supercritical carbon dioxide and water to induce a reaction on the zinc surface, which resulted in growth of zinc hydroxycarbonate nanowires into flower-like shapes. This artificial patina nanostructure predicts high surface area and offers interesting opportunities for its use in industrial high-end applications. The nanowires can significantly improve paint adhesion and promote electrochemical stability for organic coatings, or be converted to ZnO nanostructures by calcining to be used in various semiconductor applications.

Dissolution-Induced Nanowire Synthesis on Hot-Dip Galvanized Surface in Supercritical Carbon Dioxide

PubMed Central

Saarimaa, Ville; Heinonen, Saara; Nikkanen, Juha-Pekka; Markkula, Antti; Väisänen, Pasi; Levänen, Erkki

2017-01-01

In this study, we demonstrate a rapid treatment method for producing a needle-like nanowire structure on a hot-dip galvanized sheet at a temperature of 50 °C. The processing method involved only supercritical carbon dioxide and water to induce a reaction on the zinc surface, which resulted in growth of zinc hydroxycarbonate nanowires into flower-like shapes. This artificial patina nanostructure predicts high surface area and offers interesting opportunities for its use in industrial high-end applications. The nanowires can significantly improve paint adhesion and promote electrochemical stability for organic coatings, or be converted to ZnO nanostructures by calcining to be used in various semiconductor applications. PMID:28696374

Modulation of Memory by Vestibular Lesions and Galvanic Vestibular Stimulation

PubMed Central

Smith, Paul F.; Geddes, Lisa H.; Baek, Jean-Ha; Darlington, Cynthia L.; Zheng, Yiwen

2010-01-01

For decades it has been speculated that there is a close association between the vestibular system and spatial memories constructed by areas of the brain such as the hippocampus. While many animal studies have been conducted which support this relationship, only in the last 10 years have detailed quantitative studies been carried out in patients with vestibular disorders. The majority of these studies suggest that complete bilateral vestibular loss results in spatial memory deficits that are not simply due to vestibular reflex dysfunction, while the effects of unilateral vestibular damage are more complex and subtle. Very recently, reports have emerged that sub-threshold, noisy galvanic vestibular stimulation can enhance memory in humans, although this has not been investigated for spatial memory as yet. These studies add to the increasing evidence that suggests a connection between vestibular sensory information and memory in humans. PMID:21173897

Performance Evaluation of CMUT-Based Ultrasonic Transformers for Galvanic Isolation.

PubMed

Heller, Jacques; Boulme, Audren; Alquier, Daniel; Ngo, Sophie; Certon, Dominique

2018-04-01

This paper presents the development of a novel acoustic transformer with high galvanic isolation dedicated to power switch triggering. The transformer is based on two capacitive micromachined ultrasonic transducers layered on each side of a silicon substrate; one is the primary circuit, and the other is the secondary circuit. The thickness mode resonance of the substrate is leveraged to transmit the triggering signal. The fabrication and characterization of an initial prototype is presented in this paper. All experimental results are discussed, from the electrical impedance measurements to the power efficiency measurements, for different electrical load conditions. A comparison with a specifically developed finite-element method model is done. Simulations are finally used to identify the optimization rules of this initial prototype. It is shown that the power efficiency can be increased from 35% to 60%, and the transmitted power can be increased from 1.6 to 45 mW/Volt.

Ion Release and Galvanic Corrosion of Different Orthodontic Brackets and Wires in Artificial Saliva.

PubMed

Tahmasbi, Soodeh; Sheikh, Tahereh; Hemmati, Yasamin B

2017-03-01

To investigate the galvanic corrosion of brackets manufactured by four different companies coupled with stainless steel (SS) or nickel-titanium (NiTi) wires in an artificial saliva solution. A total of 24 mandibular central incisor Roth brackets of four different manufacturers (American Orthodontics, Dentaurum, Shinye, ORJ) were used in this experimental study. These brackets were immersed in artificial saliva along with SS or NiTi orthodontic wires (0.016'', round) for 28 days. The electric potential difference of each bracket/ wire coupled with a saturated calomel reference electrode was measured via a voltmeter and recorded constantly. Corrosion rate (CR) was calculated, and release of ions was measured with an atomic absorption spectrometer. Stereomicroscope was used to evaluate all samples. Then, samples with corrosion were further assessed by scanning electron microscope and energy-dispersive X-ray spectroscopy. Two-way analysis of variance was used to analyze data. Among ions evaluated, release of nickel ions from Shinye brackets was significantly higher than that of other brackets. The mean potential difference was significantly lower in specimens containing a couple of Shinye brackets and SS wire compared with other specimens. No significant difference was observed in the mean CR of various groups (p > 0.05). Microscopic evaluation showed corrosion in two samples only: Shinye bracket coupled with SS wire and American Orthodontics bracket coupled with NiTi wire. Shinye brackets coupled with SS wire showed more susceptibility to galvanic corrosion. There were no significant differences among specimens in terms of the CR or released ions except the release of Ni ions, which was higher in Shinye brackets.

Lens-free shadow image based high-throughput continuous cell monitoring technique.

PubMed

Jin, Geonsoo; Yoo, In-Hwa; Pack, Seung Pil; Yang, Ji-Woon; Ha, Un-Hwan; Paek, Se-Hwan; Seo, Sungkyu

2012-01-01

A high-throughput continuous cell monitoring technique which does not require any labeling reagents or destruction of the specimen is demonstrated. More than 6000 human alveolar epithelial A549 cells are monitored for up to 72 h simultaneously and continuously with a single digital image within a cost and space effective lens-free shadow imaging platform. In an experiment performed within a custom built incubator integrated with the lens-free shadow imaging platform, the cell nucleus division process could be successfully characterized by calculating the signal-to-noise ratios (SNRs) and the shadow diameters (SDs) of the cell shadow patterns. The versatile nature of this platform also enabled a single cell viability test followed by live cell counting. This study firstly shows that the lens-free shadow imaging technique can provide a continuous cell monitoring without any staining/labeling reagent and destruction of the specimen. This high-throughput continuous cell monitoring technique based on lens-free shadow imaging may be widely utilized as a compact, low-cost, and high-throughput cell monitoring tool in the fields of drug and food screening or cell proliferation and viability testing. Copyright © 2012 Elsevier B.V. All rights reserved.

Filter paper-assisted cell transfer (FaCT) technique: A novel cell-sampling technique for intraoperative diagnosis of central nervous system tumors.

PubMed

Kawamura, Jumpei; Kamoshida, Shingo; Shimakata, Takaaki; Hayashi, Yurie; Sakamaki, Kuniko; Denda, Tamami; Kawai, Kenji; Kuwao, Sadahito

2017-04-01

Intraoperative diagnosis of central nervous system (CNS) tumors provides critical guidance to surgeons in the determination of surgical resection margins and treatment. The techniques and preparations used for the intraoperative diagnosis of CNS tumors include frozen sectioning and cytologic methods (squash smear and touch imprint). Cytologic specimens, which do not have freezing artifacts, are important as an adjuvant tool to frozen sections. However, if the amount of submitted tissue samples is limited, then it is difficult to prepare both frozen sections and squash smears or touch imprint specimens from a single sample at the same time. Therefore, the objective of this study was to derive cells directly from filter paper on which tumor samples are placed. The authors established the filter paper-assisted cell transfer (FaCT) smear technique, in which tumor cells are transferred onto a glass slide directly from the filter paper sample spot after the biopsy is removed. Cell yields and diagnostic accuracy of the FaCT smears were assessed in 40 CNS tumors. FaCT smears had ample cell numbers and well preserved cell morphology sufficient for cytologic diagnosis, even if the submitted tissues were minimal. The overall diagnostic concordance rates between frozen sections and FaCT smears were 90% and 87.5%, respectively (no significant differences). When combining FaCT smears with frozen sections, the diagnostic concordance rate rose to 92.5%. The current results suggest that the FaCT smear technique is a simple and effective processing method that has significant value for intraoperative diagnosis of CNS tumors. Cancer Cytopathol 2017;125:277-282. © 2016 American Cancer Society. © 2017 American Cancer Society.

Thermodynamic Activity Measurements with Knudsen Cell Mass Spectrometry

NASA Technical Reports Server (NTRS)

Copland, Evan H.; Jacobson, Nathan S.

2001-01-01

Coupling the Knudsen effusion method with mass spectrometry has proven to be one of the most useful experimental techniques for studying the equilibrium between condensed phases and complex vapors. The Knudsen effusion method involves placing a condensed sample in a Knudsen cell, a small "enclosure", that is uniformly heated and held until equilibrium is attained between the condensed and vapor phases. The vapor is continuously sampled by effusion through a small orifice in the cell. A molecular beam is formed from the effusing vapor and directed into a mass spectrometer for identification and pressure measurement of the species in the vapor phase. Knudsen cell mass spectrometry (KCMS) has been used for nearly fifty years now and continues to be a leading technique for obtaining thermodynamic data. Indeed, much of the well-established vapor specie data in the JANAF tables has been obtained from this technique. This is due to the extreme versatility of the technique. All classes of materials can be studied and all constituents of the vapor phase can be measured over a wide range of pressures (approximately 10(exp -4) to 10(exp -11) bar) and temperatures (500-2800 K). The ability to selectively measure different vapor species makes KCMS a very powerful tool for the measurement of component activities in metallic and ceramic solutions. Today several groups are applying KCMS to measure thermodynamic functions in multicomponent metallic and ceramic systems. Thermodynamic functions, especially component activities, are extremely important in the development of CALPHAD (Calculation of Phase Diagrams) type thermodynamic descriptions. These descriptions, in turn, are useful for modeling materials processing and predicting reactions such as oxide formation and fiber/matrix interactions. The leading experimental methods for measuring activities are the Galvanic cell or electro-motive force (EMF) technique and the KCMS technique. Each has specific advantages, depending on

Anodized titanium and stainless steel in contact with CFRP: an electrochemical approach considering galvanic corrosion.

PubMed

Mueller, Yves; Tognini, Roger; Mayer, Joerg; Virtanen, Sannakaisa

2007-09-15

The combination of different materials in an implant gives the opportunity to better fulfill the requirements that are needed to improve the healing process. However, using different materials increases the risk of galvanic coupling corrosion. In this study, coupling effects of gold-anodized titanium, stainless steel for biomedical applications, carbon fiber reinforced polyetheretherketone (CFRP), and CFRP containing tantalum fibers are investigated electrochemically and by long-term immersion experiments in simulated body fluid (SBF). Potentiodynamic polarization experiments (i/E curves) and electrochemical impedance spectroscopy (EIS) of the separated materials showed a passive behavior of the metallic samples. Anodized titanium showed no corrosion attacks, whereas stainless steel is highly susceptibility for localized corrosion. On the other side, an active dissolution behavior of both of the CFRPs in the given environment could be determined, leading to delaminating of the carbon fibers from the matrix. Long-term immersion experiments were carried out using a set-up especially developed to simulate coupling conditions of a point contact fixator system (PC-Fix) in a biological environment. Electrochemical data were acquired in situ during the whole immersion time. The results of the immersion experiments correlate with the findings of the electrochemical investigation. Localized corrosion attacks were found on stainless steel, whereas anodized titanium showed no corrosion attacks. No significant differences between the two CFRP types could be found. Galvanic coupling corrosion in combination with crevice conditions and possible corrosion mechanisms are discussed. Copyright 2007 Wiley Periodicals, Inc.

The recovery of zinc from hot galvanizing slag in an anion-exchange membrane electrolysis reactor.

PubMed

Ren, Xiulian; Wei, Qifeng; Hu, Surong; Wei, Sijie

2010-09-15

This paper reports the optimization of the process parameters for recovery of zinc from hot galvanizing slag in an anion-exchange membrane electrolysis reactor. The experiments were carried out in an ammoniacal ammonium chloride system. The influence of composition of electrolytes, pH, stirring rate, current density and temperature, on cathodic current efficiency, specific power consumption and anodic dissolution of Zn were investigated. The results indicate that the cathode current efficiency increases and the hydrogen evolution decreased with increasing the cathode current density. The partial current for electrodeposition of Zn has liner relationship with omega(1/2) (omega: rotation rate). The highest current efficiency for dissolving zinc was obtained when NH(4)Cl concentration was 53.46 g L(-1) and the anodic dissolution of zinc was determined by mass transfer rate at stirring rate 0-300 r min(-1). Increase in temperature benefits to improve CE and dissolution of Zn, and reduce cell voltage. Initial pH of electrolytes plays an important role in the deposition and anodic dissolution of Zn. The results of single factor experiment show that about 50% energy consumption was saved for electrodeposition of Zn in the anion-exchange membrane electrolysis reactor. Copyright 2010 Elsevier B.V. All rights reserved.

Thermodynamic Study of the Nickel Addition in Zinc Hot-Dip Galvanizing Baths

NASA Astrophysics Data System (ADS)

Pistofidis, N.; Vourlias, G.

2010-01-01

A usual practice during zinc hot-dip galvanizing is the addition of nickel in the liquid zinc which is used to inhibit the Sandelin effect. Its action is due to the fact that the ζ (zeta) phase of the Fe-Zn system is replaced by the Τ (tau) phase of the Fe-Zn-Ni system. In the present work an attempt is made to explain the formation of the Τ phase with thermodynamics. For this reason the Gibbs free energy changes for Τ and ζ phases were calculated. The excess free energy for the system was calculated with the Redlich-Kister polyonyme. From this calculation it was deduced that the Gibbs energy change for the tau phase is negative. As a result its formation is spontaneous.

A photoacoustic technique to measure the properties of single cells

NASA Astrophysics Data System (ADS)

Strohm, Eric M.; Berndl, Elizabeth S. L.; Kolios, Michael C.

2013-03-01

We demonstrate a new technique to non-invasively determine the diameter and sound speed of single cells using a combined ultrasonic and photoacoustic technique. Two cell lines, B16-F1 melanoma cells and MCF7 breast cancer cells were examined using this technique. Using a 200 MHz transducer, the ultrasound backscatter from a single cell in suspension was recorded. Immediately following, the cell was irradiated with a 532 nm laser and the resulting photoacoustic wave recorded by the same transducer. The melanoma cells contain optically absorbing melanin particles, which facilitated photoacoustic wave generation. MCF7 cells have negligible optical absorption at 532 nm; the cells were permeabilized and stained with trypan blue prior to measurements. The measured ultrasound and photoacoustic power spectra were compared to theoretical equations with the cell diameter and sound speed as variables (Anderson scattering model for ultrasound, and a thermoelastic expansion model for photoacoustics). The diameter and sound speed were extracted from the models where the spectral shape matched the measured signals. However the photoacoustic spectrum for the melanoma cell did not match theory, which is likely because melanin particles are located around the cytoplasm, and not within the nucleus. Therefore a photoacoustic finite element model of a cell was developed where the central region was not used to generate a photoacoustic wave. The resulting power spectrum was in better agreement with the measured signal than the thermoelastic expansion model. The MCF7 cell diameter obtained using the spectral matching method was 17.5 μm, similar to the optical measurement of 16 μm, while the melanoma cell diameter obtained was 22 μm, similar to the optical measurement of 21 μm. The sound speed measured from the MCF7 and melanoma cell was 1573 and 1560 m/s, respectively, which is within acceptable values that have been published in literature.

Trend of Mathematical Models in Microbial Fuel Cell for Environmental Energy Refinery from Waste/Water

NASA Astrophysics Data System (ADS)

Oh, Sung Taek

A microbial fuel cell (MFC) is a device to use for bio electrochemical energy production. Electrophilic bacteria produce electrons in their metabolic pathway and the electrons can be extracted and concentrated on electrode by the electric potential difference (i.e. Galvanic cell). The bio-electrode may provide new opportunities for the renewable energy in waste water/swage treatment plants.

Ion exchange treatment of rinse water generated in the galvanizing process.

PubMed

Marañón, Elena; Fernández, Yolanda; Castrillón, Leonor

2005-01-01

A study was conducted of the viability of using the cationic exchange resins Amberlite IR-120 and Lewatit SP-112 to treat rinse water generated in the galvanizing process as well as acidic wastewater containing zinc (Zn) and iron (Fe). Solutions containing either 100 mg/L of Zn at pH 5.6 (rinse water) or Fe and Zn at concentrations of 320 and 200 mg/L at pH 1.5 (acidic water), respectively, were percolated through packed beds until the resins were exhausted. Breakthrough capacities obtained ranged between 1.1 and 1.5 meq metal/mL resin. The elution of metal and the regeneration of resins were performed with hydrochloric acid. The influence of the flowrate used during the loading stage was also studied, with 0.5 bed volumes/min (3.2 cm/min) found to be the optimum flowrate.

Get to Understand More from Single-Cells: Current Studies of Microfluidic-Based Techniques for Single-Cell Analysis.

PubMed

Lo, Shih-Jie; Yao, Da-Jeng

2015-07-23

This review describes the microfluidic techniques developed for the analysis of a single cell. The characteristics of microfluidic (e.g., little sample amount required, high-throughput performance) make this tool suitable to answer and to solve biological questions of interest about a single cell. This review aims to introduce microfluidic related techniques for the isolation, trapping and manipulation of a single cell. The major approaches for detection in single-cell analysis are introduced; the applications of single-cell analysis are then summarized. The review concludes with discussions of the future directions and opportunities of microfluidic systems applied in analysis of a single cell.

Theory of the inverse spin galvanic effect in quantum wells

NASA Astrophysics Data System (ADS)

Maleki Sheikhabadi, Amin; Miatka, Iryna; Sherman, E. Ya.; Raimondi, Roberto

2018-06-01

The understanding of the fundamentals of spin and charge densities and currents interconversion by spin-orbit coupling can enable efficient applications beyond the possibilities offered by conventional electronics. For this purpose we consider various forms of the frequency-dependent inverse spin galvanic effect in semiconductor quantum wells and epilayers taking into account the cubic in the electron momentum spin-orbit coupling in the Rashba and Dresselhaus forms, concentrating on the current-induced spin polarization (CISP). We find that including the cubic terms qualitatively explains recent findings of the CISP in InGaAs epilayers being the strongest if the internal spin-orbit coupling field is the smallest and vice versa [Norman et al., Phys. Rev. Lett. 112, 056601 (2014), 10.1103/PhysRevLett.112.056601; Luengo-Kovac et al., Phys. Rev. B 96, 195206 (2017), 10.1103/PhysRevB.96.195206], in contrast to the common understanding. Our results provide a promising framework for the control of spin transport in future spintronics devices.

Development of a Cell Sheet Transportation Technique for Regenerative Medicine

PubMed Central

Oie, Yoshinori; Nozaki, Takayuki; Takayanagi, Hiroshi; Hara, Susumu; Hayashi, Ryuhei; Takeda, Shizu; Mori, Keisuke; Moriya, Noboru; Soma, Takeshi; Tsujikawa, Motokazu; Saito, Kazuo

2014-01-01

Purpose: A transportation technique for cell sheets is necessary to standardize regenerative medicine. The aim of this article is to develop and evaluate a new transportation technique for cell sheets. Material and Methods: We developed a transportation container with three basic functions: the maintenance of interior temperature, air pressure, and sterility. The interior temperature and air pressure were monitored by a recorder. Human oral mucosal epithelial cells obtained from two healthy volunteers were cultured on temperature-responsive culture dishes. The epithelial cell sheets were transported via an airplane between the Osaka University and Tohoku University using the developed cell transportation container. Histological and immunohistochemical analyses and flow cytometric analyses for cell viability and cell purity were performed for the cell sheets before and 12 h after transportation to assess the influence of transportation on the cell sheets. Sterility tests and screening for endotoxin and mycoplasma in the cell sheets were performed before and after transportation. Results: During transportation via an airplane, the temperature inside the container was maintained above 32°C, and the changes in air pressure remained within 10 hPa. The cell sheets were well stratified and successfully harvested before and after transportation. The expression patterns of keratin 3/76, p63, and MUC16 were equivalent before and after transportation. However, the expression of ZO-1 in the cell sheet after transportation was slightly weaker than that before transportation. The cell viability was 72.0% before transportation and 77.3% after transportation. The epithelial purity was 94.6% before transportation and 87.9% after transportation. Sterility tests and screening for endotoxin and mycoplasma were negative for all cell sheets. Conclusion: The newly developed transportation technique for air travel is essential technology for regenerative medicine and promotes the

Development of a cell sheet transportation technique for regenerative medicine.

PubMed

Oie, Yoshinori; Nozaki, Takayuki; Takayanagi, Hiroshi; Hara, Susumu; Hayashi, Ryuhei; Takeda, Shizu; Mori, Keisuke; Moriya, Noboru; Soma, Takeshi; Tsujikawa, Motokazu; Saito, Kazuo; Nishida, Kohji

2014-05-01

A transportation technique for cell sheets is necessary to standardize regenerative medicine. The aim of this article is to develop and evaluate a new transportation technique for cell sheets. We developed a transportation container with three basic functions: the maintenance of interior temperature, air pressure, and sterility. The interior temperature and air pressure were monitored by a recorder. Human oral mucosal epithelial cells obtained from two healthy volunteers were cultured on temperature-responsive culture dishes. The epithelial cell sheets were transported via an airplane between the Osaka University and Tohoku University using the developed cell transportation container. Histological and immunohistochemical analyses and flow cytometric analyses for cell viability and cell purity were performed for the cell sheets before and 12 h after transportation to assess the influence of transportation on the cell sheets. Sterility tests and screening for endotoxin and mycoplasma in the cell sheets were performed before and after transportation. During transportation via an airplane, the temperature inside the container was maintained above 32°C, and the changes in air pressure remained within 10 hPa. The cell sheets were well stratified and successfully harvested before and after transportation. The expression patterns of keratin 3/76, p63, and MUC16 were equivalent before and after transportation. However, the expression of ZO-1 in the cell sheet after transportation was slightly weaker than that before transportation. The cell viability was 72.0% before transportation and 77.3% after transportation. The epithelial purity was 94.6% before transportation and 87.9% after transportation. Sterility tests and screening for endotoxin and mycoplasma were negative for all cell sheets. The newly developed transportation technique for air travel is essential technology for regenerative medicine and promotes the standardization and spread of regenerative therapies.

Solid oxide fuel cell having monolithic core

DOEpatents

Ackerman, John P.; Young, John E.

1984-01-01

A solid oxide fuel cell for electrochemically combining fuel and oxidant for generating galvanic output, wherein the cell core has an array of electrolyte and interconnect walls that are substantially devoid of any composite inert materials for support. Instead, the core is monolithic, where each electrolyte wall consists of thin layers of cathode and anode materials sandwiching a thin layer of electrolyte material therebetween, and each interconnect wall consists of thin layers of the cathode and anode materials sandwiching a thin layer of interconnect material therebetween. The electrolyte walls are arranged and backfolded between adjacent interconnect walls operable to define a plurality of core passageways alternately arranged where the inside faces thereof have only the anode material or only the cathode material exposed. Means direct the fuel to the anode-exposed core passageways and means direct the oxidant to the cathode-exposed core passageway; and means also direct the galvanic output to an exterior circuit. Each layer of the electrolyte and interconnect materials is of the order of 0.002-0.01 cm thick; and each layer of the cathode and anode materials is of the order of 0.002-0.05 cm thick.

Solid oxide fuel cell having monolithic core

DOEpatents

Ackerman, J.P.; Young, J.E.

1983-10-12

A solid oxide fuel cell is described for electrochemically combining fuel and oxidant for generating galvanic output, wherein the cell core has an array of electrolyte and interconnect walls that are substantially devoid of any composite inert materials for support. Instead, the core is monolithic, where each electrolyte wall consists of thin layers of cathode and anode materials sandwiching a thin layer of electrolyte material therebetween. The electrolyte walls are arranged and backfolded between adjacent interconnect walls operable to define a plurality of core passageways alternately arranged where the inside faces thereof have only the anode material or only the cathode material exposed. Means direct the fuel to the anode-exposed core passageways and means direct the oxidant to the anode-exposed core passageways and means direct the oxidant to the cathode-exposed core passageway; and means also direct the galvanic output to an exterior circuit. Each layer of the electrolyte and interconnect materials is of the order of 0.002 to 0.01 cm thick; and each layer of the cathode and anode materials is of the order of 0.002 to 0.05 cm thick.

Cell-material interactions revealed via material techniques of surface patterning.

PubMed

Yao, Xiang; Peng, Rong; Ding, Jiandong

2013-10-04

Cell-material interactions constitute a key fundamental topic in biomaterials study. Various cell cues and matrix cues as well as soluble factors regulate cell behaviors on materials. These factors are coupled with each other as usual, and thus it is very difficult to unambiguously elucidate the role of each regulator. The recently developed material techniques of surface patterning afford unique ways to reveal the underlying science. This paper reviews the pertinent material techniques to fabricate patterns of microscale and nanoscale resolutions, and corresponding cell studies. Some issues are emphasized, such as cell localization on patterned surfaces of chemical contrast, and effects of cell shape, cell size, cell-cell contact, and seeding density on differentiation of stem cells. Material cues to regulate cell adhesion, cell differentiation and other cell events are further summed up. Effects of some physical properties, such as surface topography and matrix stiffness, on cell behaviors are also discussed; nanoscaled features of substrate surfaces to regulate cell fate are summarized as well. The pertinent work sheds new insight into the cell-material interactions, and is stimulating for biomaterial design in regenerative medicine, tissue engineering, and high-throughput detection, diagnosis, and drug screening. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Influence of laser beam incidence angle on laser lap welding quality of galvanized steels

NASA Astrophysics Data System (ADS)

Mei, Lifang; Yan, Dongbing; Chen, Genyu; Wang, Zhenhui; Chen, Shuixuan

2017-11-01

Based on the characteristics of laser welded structural parts of auto bodies, the influence of variation in laser beam incidence angle on the lap welding performance of galvanized auto-body sheets was studied. Lap welding tests were carried out on the galvanized sheets for auto-body application at different laser beam incidence angles by using the optimal welding parameters obtained through orthogonal experiment. The effects of incidence angle variation on seam appearance, cross-sectional shape, joint mechanical properties and microstructure of weldments were analyzed. In addition, the main factors influencing the value of incidence angle were investigated. According to the results, the weld seams had a good appearance as well as a fine, and uniform microstructure when the laser beam incidence angle was smaller than the critical incidence angle, and thus they could withstand great tensile and shear loads. Moreover, all tensile-shear specimens were fractured in the base material zone. When the laser beam incidence angle was larger than the critical incidence angle, defects like shrinkage and collapse tended to emerge, thereby resulting in the deteriorated weldability of specimens. Meanwhile, factors like the type and thickness of sheet, weld width as well as inter-sheet gap all had a certain effect on the value of laser beam incidence angle. When the sheet thickness was small and the weld width was narrow, the laser beam incidence angle could be increased appropriately. At the same time, small changes in the inter-sheet gap could greatly impact the value of incidence angle. When the inter-sheet gap was small, the laser beam incidence angle should not be too large.

Urinary nickel as bioindicator of workers' Ni exposure in a galvanizing plant in Brazil.

PubMed

Oliveira, J P; de Siqueira, M E; da Silva, C S

2000-01-01

We measured urinary nickel (U-Ni) in ten workers (97 samples) from a galvanizing plant that uses nickel sulfate, and in ten control subjects (55 samples) to examine the association between occupational exposure to airborne Ni and Ni absorption. Samples from the exposed group were taken before and after the work shift on 5 successive workdays. At the same time airborne Ni (A-Ni) was measured using personal samplers. Ni levels in biological material and in the airborne were determined by a graphite furnace atomic absorption spectrometry validated method. In the control group the urine samples were collected twice a day, in the before and after the work shift, on 3 successive days. Ni exposure low to moderate was detected in all the examined places in the plant, the airborne levels varying between 2.8 and 116.7 micrograms/m3 and the urine levels, from samples taken postshift, between 4.5 and 43.2 micrograms/g creatinine (mean 14.7 micrograms/g creatinine). Significant differences in U-Ni creatinine were seen between the exposed and control groups (Student's t test, P < or = 0.01). A significant correlation between U-Ni and A-Ni (r = 0.96; P < or = 0.001) was detected. No statistical difference was observed in U-Ni collected from exposed workers in the 5 successive days, but significant difference was observed between pre- and postshift samples. Urinary nickel may be used as a reliable internal dose bioindicator in biological monitoring of workers exposed to Ni sulfate in galvanizing plants regardless of the day of the workweek on which the samples are collected.

Solid oxide fuel cell simulation and design optimization with numerical adjoint techniques

NASA Astrophysics Data System (ADS)

Elliott, Louie C.

This dissertation reports on the application of numerical optimization techniques as applied to fuel cell simulation and design. Due to the "multi-physics" inherent in a fuel cell, which results in a highly coupled and non-linear behavior, an experimental program to analyze and improve the performance of fuel cells is extremely difficult. This program applies new optimization techniques with computational methods from the field of aerospace engineering to the fuel cell design problem. After an overview of fuel cell history, importance, and classification, a mathematical model of solid oxide fuel cells (SOFC) is presented. The governing equations are discretized and solved with computational fluid dynamics (CFD) techniques including unstructured meshes, non-linear solution methods, numerical derivatives with complex variables, and sensitivity analysis with adjoint methods. Following the validation of the fuel cell model in 2-D and 3-D, the results of the sensitivity analysis are presented. The sensitivity derivative for a cost function with respect to a design variable is found with three increasingly sophisticated techniques: finite difference, direct differentiation, and adjoint. A design cycle is performed using a simple optimization method to improve the value of the implemented cost function. The results from this program could improve fuel cell performance and lessen the world's dependence on fossil fuels.

A novel cell culture technique for electron microscopy.

PubMed

Wang, F; Ledford, L B; Head, J F; Elliott, R L

1993-12-15

A simplified technique for the monolayer growth of cultured cells and their in situ embedment on the inner surface of the pyramidal portion of the Beem capsule for electron microscopy has been developed. The results demonstrated that the cell monolayers grew well on the surface of the Beem capsule and could be embedded in situ. Electron micrographs showed cells in their natural state of contact with one another. The plasma membrane and intracellular organelles were well preserved. This method minimizes many difficult steps and eliminates the disruption of cells by scraping, pelleting, or enzymatic reaction to remove them.

Get to Understand More from Single-Cells: Current Studies of Microfluidic-Based Techniques for Single-Cell Analysis

PubMed Central

Lo, Shih-Jie; Yao, Da-Jeng

2015-01-01

This review describes the microfluidic techniques developed for the analysis of a single cell. The characteristics of microfluidic (e.g., little sample amount required, high-throughput performance) make this tool suitable to answer and to solve biological questions of interest about a single cell. This review aims to introduce microfluidic related techniques for the isolation, trapping and manipulation of a single cell. The major approaches for detection in single-cell analysis are introduced; the applications of single-cell analysis are then summarized. The review concludes with discussions of the future directions and opportunities of microfluidic systems applied in analysis of a single cell. PMID:26213918

A detailed study of gold-nanoparticle loaded cells using X-ray based techniques for cell-tracking applications with single-cell sensitivity

NASA Astrophysics Data System (ADS)

Astolfo, Alberto; Arfelli, Fulvia; Schültke, Elisabeth; James, Simon; Mancini, Lucia; Menk, Ralf-Hendrik

2013-03-01

In the present study complementary high-resolution imaging techniques on different length scales are applied to elucidate a cellular loading protocol of gold nanoparticles and subsequently its impact on long term and high-resolution cell-tracking utilizing X-ray technology. Although demonstrated for malignant cell lines the results can be applied to non-malignant cell lines as well. In particular the accumulation of the gold marker per cell has been assessed quantitatively by virtue of electron microscopy, two-dimensional X-ray fluorescence imaging techniques and X-ray CT with micrometric and sub-micrometric resolution. Moreover, utilizing these techniques the three dimensional distribution of the incorporated nanoparticles, which are sequestered in lysosomes as a permanent marker, could be determined. The latter allowed elucidation of the gold partition during mitosis and the cell size, which subsequently enabled us to define the optimal instrument settings of a compact microCT system to visualize gold loaded cells. The results obtained demonstrate the feasibility of cell-tracking using X-ray CT with compact sources.

Application of thermodynamics and Wagner model on two problems in continuous hot-dip galvanizing

NASA Astrophysics Data System (ADS)

Liu, Huachu; He, Yanlin; Li, Lin

2009-12-01

Firstly in this paper, the influence of H 2 and water vapor content on selective oxidation occurred in continuous hot-dip galvanizing has been studied by thermodynamics and Wagner model, then, the Gibbs energy of each possible aluminothermic reducing reaction in zinc bath was calculated in order to judge the possibility of these reactions. It was found that oxides' amounts and oxidation type were greatly related to the H 2 and water content in the annealing atmosphere. And from the view of thermodynamics, surface oxides (MnO, Cr 2O 3, SiO 2 etc.) can be reduced by the effective Al in Zn bath.

Characterization of hydrogen responsive nanoporous palladium films synthesized via a spontaneous galvanic displacement reaction.

PubMed

Patton, J F; Lavrik, N V; Joy, D C; Hunter, S R; Datskos, P G; Smith, D B; Sepaniak, M J

2012-11-23

A model is presented regarding the mechanistic properties associated with the interaction of hydrogen with nanoporous palladium (np-Pd) films prepared using a spontaneous galvanic displacement reaction (SGDR), which involves PdCl(2) reduction by atomic Ag. Characterization of these films shows both chemical and morphological factors, which influence the performance characteristics of np-Pd microcantilever (MC) nanomechanical sensing devices. Raman spectroscopy, uniquely complemented with MC response profiles, is used to explore the chemical influence of palladium oxide (PdO). These combined techniques support a reaction mechanism that provides for rapid response to H(2) and recovery in the presence of O(2). Post-SGDR processing via reduction of PdCl(2)(s) in a H(2) environment results in a segregated nanoparticle three-dimensional matrix dispersed in a silver layer. The porous nature of the reduced material is shown by high resolution scanning electron microscopy. Extended grain boundaries, typical of these materials, result in a greater surface area conducive to fast sorption/desorption of hydrogen, encouraged by the presence of PdO. X-ray diffraction and inductively coupled plasma-optical emission spectroscopy are employed to study changes in morphology and chemistry occurring in these nanoporous films under different processing conditions. The unique nature of chemical/morphological effects, as demonstrated by the above characterization methods, provides evidence in support of observed nanomechanical response/recovery profiles offering insight for catalysis, H(2) storage and improved sensing applications.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rakshit, S.K.; Naik, Y.P.; Parida, S.C.

Three ternary oxides LiAl{sub 5}O{sub 8}(s), LiAlO{sub 2}(s) and Li{sub 5}AlO{sub 4}(s) in the system Li-Al-O were prepared by solid-state reaction route and characterized by X-ray powder diffraction method. Equilibrium partial pressure of CO{sub 2}(g) over the three-phase mixtures {l_brace}LiAl{sub 5}O{sub 8}(s)+Li{sub 2}CO{sub 3}(s)+5Al{sub 2}O{sub 3}(s){r_brace}, {l_brace}LiAl{sub 5}O{sub 8}(s)+5LiAlO{sub 2}(s)+2Li{sub 2}CO{sub 3}(s){r_brace} and {l_brace}LiAlO{sub 2}(s)+Li{sub 5}AlO{sub 4}(s)+2Li{sub 2}CO{sub 3}(s){r_brace} were measured using Knudsen effusion quadrupole mass spectrometry (KEQMS). Solid-state galvanic cell technique based on calcium fluoride electrolyte was used to determine the standard molar Gibbs energies of formations of these aluminates. The standard molar Gibbs energies of formation of thesemore » three aluminates calculated from KEQMS and galvanic cell measurements were in good agreement. Heat capacities of individual ternary oxides were measured from 127 to 868 K using differential scanning calorimetry. Thermodynamic tables representing the values of {delta}{sub f}H{sup 0}(298.15 K), S{sup 0}(298.15 K) S{sup 0}(T), C{sub p}{sup 0}(T), H{sup 0}(T), {l_brace}H{sup 0}(T)-H{sup 0}(298.15 K){r_brace}, G{sup 0}(T), {delta}{sub f}H{sup 0}(T), {delta}{sub f}G{sup 0}(T) and free energy function (fef) were constructed using second law analysis and FACTSAGE thermo-chemical database software. - Graphical abstract: Comparison of {delta}{sub f}G{sub m}{sup 0} of ternary oxides determined from KEQMS and solid-state galvanic cell techniques. (O) KEQMS, (9632;) solid-state galvanic cell and solid line: combined fit of both the experimental data.« less

Cold laser technique for cell surgery

NASA Astrophysics Data System (ADS)

Palanker, Daniel V.; Ohad, Shoshanit; Lewis, Aaron; Laufer, Neri

1992-08-01

A new cell surgery technique has been developed to produce well-defined alterations in cells and tissues without detectable heating and/or other structural damage in the surroundings. The technique involves the use of a 193 nm argon fluoride excimer laser which is guided through a glass pipette filled with a positive air pressure. To demonstrate the method holes were drilled in the zona pellucida of mouse oocytes. The diameter of the drilled hole was determined by the pipette tip size, and its depth by an energy emitted per pulse and number of pulses. Scanning electron microscopy of the drilled mouse oocytes showed uniform, round, well circumscribed holes with sharp edges. Oocytes that had their zona pellucida drilled with this new method fertilized in vitro and developed to the blastocyst stage in a rate similar to that of control group. These results demonstrate the non-perturbing nature of this cold laser microsurgical procedure. In addition to the extension of our results for clinical in vitro fertilization purposes, such as enhancement of fertilization and embryo biopsy, there are wide ranging possible uses of our method in fundamental and applied investigations that require sub-micron accuracy in cellular alteration.

Electron tomography of whole cultured cells using novel transmission electron imaging technique.

PubMed

Okumura, Taiga; Shoji, Minami; Hisada, Akiko; Ominami, Yusuke; Ito, Sukehiro; Ushiki, Tatsuo; Nakajima, Masato; Ohshima, Takashi

2018-01-01

Since a three-dimensional (3D) cellular ultrastructure is significant for biological functions, it has been investigated using various electron microscopic techniques. Although transmission electron microscopy (TEM)-based techniques are traditionally used, cells must be embedded in resin and sliced into ultrathin sections in sample preparation processes. Block-face observation using a scanning electron microscope (SEM) has also been recently applied to 3D observation of cellular components, but this is a destructive inspection and does not allow re-examination. Therefore, we developed electron tomography using a transmission electron imaging technique called Plate-TEM. With Plate-TEM, the cells cultured directly on a scintillator plate are inserted into a conventional SEM equipped with a Plate-TEM observation system, and their internal structures are observed by detecting scintillation light produced by electrons passing through the cells. This technology has the following four advantages. First, the cells cultured on the plate can be observed at electron-microscopic resolution since they remain on the plate. Second, both surface and internal information can be obtained simultaneously by using electron- and photo-detectors, respectively, because a Plate-TEM detector is installed in an SEM. Third, the cells on the scintillator plate can also be inspected using light microscopy because the plate has transparent features. Finally, correlative observation with other techniques, such as conventional TEM, is possible after Plate-TEM observation because Plate-TEM is a non-destructive analysis technique. We also designed a sample stage to tilt the samples for tomography with Plate-TEM, by which 3D organization of cellular structures can be visualized as a whole cell. In the present study, Mm2T cells were investigated using our tomography system, resulting in 3D visualization of cell organelles such as mitochondria, lipid droplets, and microvilli. Correlative observations

A Novel Technique for Performing PID Susceptibility Screening during the Solar Cell Fabrication Process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oh, Jaewon; Dahal, Som; Dauksher, Bill

2016-11-21

Various characterization techniques have historically been developed in order to screen potential induced degradation (PID)-susceptible cells, but those techniques require final solar cells. We present a new characterization technique for screening PID-susceptible cells during the cell fabrication process. Illuminated Lock-In Thermography (ILIT) was used to image PID shunting of the cell without metallization and clearly showed PID-affected areas. PID-susceptible cells can be screened by ILIT, and the sample structure can advantageously be simplified as long as the sample has the silicon nitride antireflection coating and an aluminum back surface field.

Mapping the Galvanic Corrosion of Three Metals Coupled with a Wire Beam Electrode: The Influence of Temperature and Relative Geometrical Position.

PubMed

Ju, Hong; Yang, Yuan-Feng; Liu, Yun-Fei; Liu, Shu-Fa; Duan, Jin-Zhuo; Li, Yan

2018-02-28

The local electrochemical properties of galvanic corrosion for three coupled metals in a desalination plant were investigated with three wire-beam electrodes as wire sensors: aluminum brass (HAl77-2), titanium (TA2), and 316L stainless steel (316L SS). These electrodes were used with artificial seawater at different temperatures. The potential and current-density distributions of the three-metal coupled system are inhomogeneous. The HAl77-2 wire anodes were corroded in the three-metal coupled system. The TA2 wires acted as cathodes and were protected; the 316L SS wires acted as secondary cathodes. The temperature and electrode arrangement have important effects on the galvanic corrosion of the three-metal coupled system. The corrosion current of the HAl77-2 increased with temperature indicating enhanced anode corrosion at higher temperature. In addition, the corrosion of HAl77-2 was more significant when the HAl77-2 wires were located in the middle of the coupled system than with the other two metal arrangement styles.

Mapping the Galvanic Corrosion of Three Metals Coupled with a Wire Beam Electrode: The Influence of Temperature and Relative Geometrical Position

PubMed Central

Liu, Yun-Fei; Liu, Shu-Fa; Duan, Jin-Zhuo

2018-01-01

The local electrochemical properties of galvanic corrosion for three coupled metals in a desalination plant were investigated with three wire-beam electrodes as wire sensors: aluminum brass (HAl77-2), titanium (TA2), and 316L stainless steel (316L SS). These electrodes were used with artificial seawater at different temperatures. The potential and current–density distributions of the three-metal coupled system are inhomogeneous. The HAl77-2 wire anodes were corroded in the three-metal coupled system. The TA2 wires acted as cathodes and were protected; the 316L SS wires acted as secondary cathodes. The temperature and electrode arrangement have important effects on the galvanic corrosion of the three-metal coupled system. The corrosion current of the HAl77-2 increased with temperature indicating enhanced anode corrosion at higher temperature. In addition, the corrosion of HAl77-2 was more significant when the HAl77-2 wires were located in the middle of the coupled system than with the other two metal arrangement styles. PMID:29495617

[Use of magnetic therapy combined with galvanization and tissue electrophoresis in the treatment of trophic ulcers].

PubMed

Alekseenko, A V; Gusak, V V; Stoliar, V F; Iftodiĭ, A G; Tarabanchuk, V V; Shcherban, N G; Naumets, A A

1993-01-01

The results of treatment of 86 patients with the use of magnetotherapy in combination with galvanization and intratissue electrophoresis are presented. To create an electric field, the "Potok-1" apparatus with a density of current equal to 0.05-0.1 mA/cm2 was employed. Simultaneously, the "MAG-30" apparatus for low-frequency magnetotherapy with induction of 30 mT and area of exposure of 20 cm2 was applied to a trophic ulcer site. The use of magnetogalvanotherapy in the complex of treatment of trophic ulcers of the lower extremities is recommended.

Thermal analysis of the exothermic reaction between galvanic porous silicon and sodium perchlorate.

PubMed

Becker, Collin R; Currano, Luke J; Churaman, Wayne A; Stoldt, Conrad R

2010-11-01

Porous silicon (PS) films up to ∼150 μm thick with specific surface area similar to 700 m(2)/g and pore diameters similar to 3 nm are fabricated using a galvanic corrosion etching mechanism that does not require a power supply. After fabrication, the pores are impregnated with the strong oxidizer sodium perchlorate (NaClO(4)) to create a composite that constitutes a highly energetic system capable of explosion. Using bomb calorimetry, the heat of reaction is determined to be 9.9 ± 1.8 and 27.3 ± 3.2 kJ/g of PS when ignited under N(2) and O(2), respectively. Differential scanning calorimetry (DSC) reveals that the energy output is dependent on the hydrogen termination of the PS.

Cell culture-based biosensing techniques for detecting toxicity in water.

PubMed

Tan, Lu; Schirmer, Kristin

2017-06-01

The significant increase of contaminants entering fresh water bodies calls for the development of rapid and reliable methods to monitor the aquatic environment and to detect water toxicity. Cell culture-based biosensing techniques utilise the overall cytotoxic response to external stimuli, mediated by a transduced signal, to specify the toxicity of aqueous samples. These biosensing techniques can effectively indicate water toxicity for human safety and aquatic organism health. In this review we account for the recent developments of the mainstream cell culture-based biosensing techniques for water quality evaluation, discuss their key features, potentials and limitations, and outline the future prospects of their development. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

A cell culture technique for human epiretinal membranes to describe cell behavior and membrane contraction in vitro.

PubMed

Wertheimer, Christian; Eibl-Lindner, Kirsten H; Compera, Denise; Kueres, Alexander; Wolf, Armin; Docheva, Denitsa; Priglinger, Siegfried G; Priglinger, Claudia; Schumann, Ricarda G

2017-11-01

To introduce a human cell culture technique for investigating in-vitro behavior of primary epiretinal cells and membrane contraction of fibrocellular tissue surgically removed from eyes with idiopathic macular pucker. Human epiretinal membranes were harvested from ten eyes with idiopathic macular pucker during standard vitrectomy. Specimens were fixed on cell culture plastic using small entomological pins to apply horizontal stress to the tissue, and then transferred to standard cell culture conditions. Cell behavior of 400 epiretinal cells from 10 epiretinal membranes was observed in time-lapse microscopy and analyzed in terms of cell migration, cell velocity, and membrane contraction. Immunocytochemistry was performed for cell type-specific antigens. Cell specific differences in migration behavior were observed comprising two phenotypes: (PT1) epiretinal cells moving fast, less directly, with small round phenotype and (PT2) epiretinal cells moving slowly, directly, with elongated large phenotype. No mitosis, no outgrowth and no migration onto the plastic were seen. Horizontal contraction measurements showed variation between specimens. Masses of epiretinal cells with a myofibroblast-like phenotype expressed cytoplasmatic α-SMA stress fibers and correlated with cell behavior characteristics (PT2). Fast moving epiretinal cells (PT1) were identified as microglia by immunostaining. This in-vitro technique using traction application allows for culturing surgically removed epiretinal membranes from eyes with idiopathic macular pucker, demonstrating cell behavior and membrane contraction of primary human epiretinal cells. Our findings emphasize the abundance of myofibroblasts, the presence of microglia and specific differences of cell behavior in these membranes. This technique has the potential to improve the understanding of pathologies at the vitreomacular interface and might be helpful in establishing anti-fibrotic treatment strategies.

Ex vivo hyperpolarized MR spectroscopy on isolated renal tubular cells: A novel technique for cell energy phenotyping.

PubMed

Juul, Troels; Palm, Fredrik; Nielsen, Per Mose; Bertelsen, Lotte Bonde; Laustsen, Christoffer

2017-08-01

It has been demonstrated that hyperpolarized 13 C MR is a useful tool to study cultured cells. However, cells in culture can alter phenotype, which raises concerns regarding the in vivo significance of such findings. Here we investigate if metabolic phenotyping using hyperpolarized 13 C MR is suitable for cells isolated from kidney tissue, without prior cell culture. Isolation of tubular cells from freshly excised kidney tissue and treatment with either ouabain or antimycin A was investigated with hyperpolarized MR spectroscopy on a 9.4 Tesla preclinical imaging system. Isolation of tubular cells from less than 2 g of kidney tissue generally resulted in more than 10 million live tubular cells. This amount of cells was enough to yield robust signals from the conversion of 13 C-pyruvate to lactate, bicarbonate and alanine, demonstrating that metabolic flux by means of both anaerobic and aerobic pathways can be quantified using this technique. Ex vivo metabolic phenotyping using hyperpolarized 13 C MR in a preclinical system is a useful technique to study energy metabolism in freshly isolated renal tubular cells. This technique has the potential to advance our understanding of both normal cell physiology as well as pathological processes contributing to kidney disease. Magn Reson Med 78:457-461, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

Red blood cell-deformability measurement: review of techniques.

PubMed

Musielak, M

2009-01-01

Cell-deformability characterization involves general measurement of highly complex relationships between cell biology and physical forces to which the cell is subjected. The review takes account of the modern technical solutions simulating the action of the force applied to the red blood cell in macro- and microcirculation. Diffraction ektacytometers and rheoscopes measure the mean deformability value for the total red blood cell population investigated and the deformation distribution index of individual cells, respectively. Deformation assays of a whole single cell are possible by means of optical tweezers. The single cell-measuring setups for micropipette aspiration and atomic force microscopy allow conducting a selective investigation of deformation parameters (e.g., cytoplasm viscosity, viscoelastic membrane properties). The distinction between instrument sensitivity to various RBC-rheological features as well as the influence of temperature on measurement are discussed. The reports quoted confront fascinating possibilities of the techniques with their medical applications since the RBC-deformability has the key position in the etiology of a wide range of conditions.

Assessment of electrochemical properties of a biogalvanic system for tissue characterisation

PubMed Central

Chandler, J.H.; Culmer, P.R.; Jayne, D.G.; Neville, A.

2015-01-01

Biogalvanic characterisation is a promising method for obtaining health-specific tissue information. However, there is a dearth of understanding in the literature regarding the underlying galvanic cell, electrode reactions and their controlling factors which limits the application of the technique. This work presents a parametric electrochemical investigation into a zinc–copper galvanic system using salt (NaCl) solution analogues at physiologically-relevant concentrations (1.71, 17.1 & 154 mM). The potential difference at open cell, closed cell maximum current and the internal resistance (based on published characterisation methods) were measured. Additionally, independent and relative polarisation scans of the electrodes were performed to improve understanding of the system. Our findings suggest that the prominent reaction at the cathode is that of oxygen-reduction, not hydrogen-evolution. Results indicate that cell potentials are influenced by the concentration of dissolved oxygen at low currents and maximum closed cell currents are limited by the rate of oxygen diffusion to the cathode. Characterised internal resistance values for the salt solutions did not correspond to theoretical values at the extremes of concentration (1.71 and 154 mM) due to electrode resistance and current limitation. Existing biogalvanic models do not consider these phenomena and should be improved to advance the technique and its practical application. PMID:25460609

An evaluation of airborne nickel, zinc, and lead exposure at hot dip galvanizing plants.

PubMed

Verma, D K; Shaw, D S

1991-12-01

Industrial hygiene surveys were conducted at three hot dip galvanizing plants to determine occupational exposure to nickel, zinc, and lead. All three plants employed the "dry process" and used 2% nickel, by weight, in their zinc baths. A total of 32 personal and area air samples were taken. The air samples were analyzed for nickel, zinc, and lead. Some samples were also analyzed for various species of nickel (i.e., metallic, soluble, and oxidic). The airborne concentrations observed for nickel and its three species, zinc, and lead at the three plants were all well below the current and proposed threshold limit values recommended by the American Conference of Governmental Industrial Hygienists (ACGIH).

The Modeling and Simulation of the Galvanic Coupling Intra-Body Communication via Handshake Channel.

PubMed

Li, Maoyuan; Song, Yong; Li, Wansong; Wang, Guangfa; Bu, Tianpeng; Zhao, Yufei; Hao, Qun

2017-04-14

Intra-body communication (IBC) is a technology using the conductive properties of the body to transmit signal, and information interaction by handshake is regarded as one of the important applications of IBC. In this paper, a method for modeling the galvanic coupling intra-body communication via handshake channel is proposed, while the corresponding parameters are discussed. Meanwhile, the mathematical model of this kind of IBC is developed. Finally, the validity of the developed model has been verified by measurements. Moreover, its characteristics are discussed and compared with that of the IBC via single body channel. Our results indicate that the proposed method will lay a foundation for the theoretical analysis and application of the IBC via handshake channel.

The use of computer imaging techniques to visualize cardiac muscle cells in three dimensions.

PubMed

Marino, T A; Cook, P N; Cook, L T; Dwyer, S J

1980-11-01

Atrial muscle cells and atrioventricular bundle cells were reconstructed using a computer-assisted three-dimensional reconstruction system. This reconstruction technique permitted these cells to be viewed from any direction. The cell surfaces were approximated using triangular tiles, and this optimization technique for cell reconstruction allowed for the computation of cell surface area and cell volume. A transparent mode is described which enables the investigator to examine internal cellular features such as the shape and location of the nucleus. In addition, more than one cell can be displayed simultaneously, and, therefore, spatial relationships are preserved and intercellular relationships viewed directly. The use of computer imaging techniques allows for a more complete collection of quantitative morphological data and also the visualization of the morphological information gathered.

Surface Oxidation of the High-Strength Steels Electrodeposited with Cu or Fe and the Resultant Defect Formation in Their Coating during the Following Galvanizing and Galvannealing Processes

NASA Astrophysics Data System (ADS)

Choi, Yun-Il; Beom, Won-Jin; Park, Chan-Jin; Paik, Doojin; Hong, Moon-Hi

2010-12-01

This study examined the surface oxidation of high-strength steels electrodeposited with Cu or Fe and the resultant defect formation in their coating during the following galvanizing and galvannealing processes. The high-strength steels were coated with an Cu or Fe layer by the electroplating method. Then, the coated steels were annealed in a reducing atmosphere, dipped in a molten zinc, and finally transformed into galvannealed steels through the galvannealing process. The formation of Si and Mn oxides on the surface of the high-strength steel was effectively suppressed, and the density of surface defects on the galvanized steel was significantly reduced by the pre-electrodeposition of Cu and Fe. This effect was more prominent for the steels electrodeposited at higher cathodic current densities. The finer electrodeposit layer formed at higher cathodic current density on the steels enabled the suppression of partial surface oxidation by Mn or Si and better wetting of Zn on the surface of the steels in the following galvanizing process. Furthermore, the pre-electrodeposited steels exhibited a smoother surface without surface cracks after the galvannealing process compared with the untreated steel. The diffusion of Fe and Zn in the Zn coating layer in the pre-electrodeposited steels appears to occur more uniformly during the galvannealing process due to the low density of surface defects induced by oxides.

Binder Jetting: A Novel Solid Oxide Fuel-Cell Fabrication Process and Evaluation

NASA Astrophysics Data System (ADS)

Manogharan, Guha; Kioko, Meshack; Linkous, Clovis

2015-03-01

With an ever-growing concern to find a more efficient and less polluting means of producing electricity, fuel cells have constantly been of great interest. Fuel cells electrochemically convert chemical energy directly into electricity and heat without resorting to combustion/mechanical cycling. This article studies the solid oxide fuel cell (SOFC), which is a high-temperature (100°C to 1000°C) ceramic cell made from all solid-state components and can operate under a wide range of fuel sources such as hydrogen, methanol, gasoline, diesel, and gasified coal. Traditionally, SOFCs are fabricated using processes such as tape casting, calendaring, extrusion, and warm pressing for substrate support, followed by screen printing, slurry coating, spray techniques, vapor deposition, and sputter techniques, which have limited control in substrate microstructure. In this article, the feasibility of engineering the porosity and configuration of an SOFC via an additive manufacturing (AM) method known as binder jet printing was explored. The anode, cathode and oxygen ion-conducting electrolyte layers were fabricated through AM sequentially as a complete fuel cell unit. The cell performance was measured in two modes: (I) as an electrolytic oxygen pump and (II) as a galvanic electricity generator using hydrogen gas as the fuel. An analysis on influence of porosity was performed through SEM studies and permeability testing. An additional study on fuel cell material composition was conducted to verify the effects of binder jetting through SEM-EDS. Electrical discharge of the AM fabricated SOFC and nonlinearity of permeability tests show that, with additional work, the porosity of the cell can be modified for optimal performance at operating flow and temperature conditions.

Mechanistic study of shape-anisotropic nanomaterials synthesized via spontaneous galvanic displacement

DOE Office of Scientific and Technical Information (OSTI.GOV)

Strand, Matthew B.; Leong, G. Jeremy; Tassone, Christopher J.

Among the broad portfolio of preparations for nanoscale materials, spontaneous galvanic displacement (SGD) is emerging as an important technology because it is capable of creating functional nanomaterials that cannot be obtained through other routes and may be used to thrift precious metals used in a broad range of applications including catalysis. With advances resulting from increased understanding of the SGD process, materials that significantly improve efficiency and potentially enable widespread adoption of next generation technologies can be synthesized. In this work, PtAg nanotubes synthesized via displacement of Ag nanowires by Pt were used as a model system to elucidate themore » fundamental mechanisms of SGD. Furthermore, characterization by X-ray diffraction (XRD), small-angle X-ray scattering (SAXS), and atom probe tomography (APT) indicates nanotubes are formed as Ag is oxidized first from the surface and then from the center of the nanowire, with Pt deposition forming a rough, heterogeneous surface on the PtAg nanotube.« less

Mechanistic study of shape-anisotropic nanomaterials synthesized via spontaneous galvanic displacement

DOE PAGES

Strand, Matthew B.; Leong, G. Jeremy; Tassone, Christopher J.; ...

2016-10-13

Among the broad portfolio of preparations for nanoscale materials, spontaneous galvanic displacement (SGD) is emerging as an important technology because it is capable of creating functional nanomaterials that cannot be obtained through other routes and may be used to thrift precious metals used in a broad range of applications including catalysis. With advances resulting from increased understanding of the SGD process, materials that significantly improve efficiency and potentially enable widespread adoption of next generation technologies can be synthesized. In this work, PtAg nanotubes synthesized via displacement of Ag nanowires by Pt were used as a model system to elucidate themore » fundamental mechanisms of SGD. Furthermore, characterization by X-ray diffraction (XRD), small-angle X-ray scattering (SAXS), and atom probe tomography (APT) indicates nanotubes are formed as Ag is oxidized first from the surface and then from the center of the nanowire, with Pt deposition forming a rough, heterogeneous surface on the PtAg nanotube.« less

Mapping the Galvanic Corrosion of Three Coupled Metal Alloys Using Coupled Multielectrode Array: Influence of Chloride Ion Concentration

PubMed Central

Duan, JinZhuo; Cao, Ning

2018-01-01

The galvanic corrosion behavior of three metal alloys commonly used in water desalination plants was investigated using coupled multielectrode arrays consisting of aluminum-brass (HAl77-2), titanium alloy (TA2), and 316L stainless steel (316L SS). The three electrode types were coupled galvanically and arranged in different geometric configurations. Their corrosion behavior was characterized as a function of the chloride concentration. The potential and current distributions of the three-electrode coupling systems display electrochemical inhomogeneity. Generally, the aluminum-brass wires are anodic versus the titanium alloy and stainless steel. The titanium alloy acts as a primary cathode, and the 316L SS acts as a secondary cathode. The corrosion rate of aluminum-brass depends on the concentration of chloride ion, with a maximum corrosion rate at a chloride concentration of 2.3 wt %. In terms of geometrical arrangements, when the anodic HAl77-2 wires are located on the edge and are connected to the 316L SS wires in the coupling system, the main anodic area enlarges, especially in the area adjacent to the 316L SS wires. When the HAl77-2 wires are located between (in the middle of) the two other types of wires, the corrosion rates are higher than the corrosion rates observed from the other two geometrical arrangements. PMID:29677150

Mapping the Galvanic Corrosion of Three Coupled Metal Alloys Using Coupled Multielectrode Array: Influence of Chloride Ion Concentration.

PubMed

Ju, Hong; Duan, JinZhuo; Yang, Yuanfeng; Cao, Ning; Li, Yan

2018-04-20

The galvanic corrosion behavior of three metal alloys commonly used in water desalination plants was investigated using coupled multielectrode arrays consisting of aluminum-brass (HAl77-2), titanium alloy (TA2), and 316L stainless steel (316L SS). The three electrode types were coupled galvanically and arranged in different geometric configurations. Their corrosion behavior was characterized as a function of the chloride concentration. The potential and current distributions of the three-electrode coupling systems display electrochemical inhomogeneity. Generally, the aluminum-brass wires are anodic versus the titanium alloy and stainless steel. The titanium alloy acts as a primary cathode, and the 316L SS acts as a secondary cathode. The corrosion rate of aluminum-brass depends on the concentration of chloride ion, with a maximum corrosion rate at a chloride concentration of 2.3 wt %. In terms of geometrical arrangements, when the anodic HAl77-2 wires are located on the edge and are connected to the 316L SS wires in the coupling system, the main anodic area enlarges, especially in the area adjacent to the 316L SS wires. When the HAl77-2 wires are located between (in the middle of) the two other types of wires, the corrosion rates are higher than the corrosion rates observed from the other two geometrical arrangements.

A stress sensor based on Galvanic Skin Response (GSR) controlled by ZigBee.

PubMed

Villarejo, María Viqueira; Zapirain, Begoña García; Zorrilla, Amaia Méndez

2012-01-01

Sometimes, one needs to control different emotional situations which can lead the person suffering them to dangerous situations, in both the medium and short term. There are studies which indicate that stress increases the risk of cardiac problems. In this study we have designed and built a stress sensor based on Galvanic Skin Response (GSR), and controlled by ZigBee. In order to check the device's performance, we have used 16 adults (eight women and eight men) who completed different tests requiring a certain degree of effort, such as mathematical operations or breathing deeply. On completion, we appreciated that GSR is able to detect the different states of each user with a success rate of 76.56%. In the future, we plan to create an algorithm which is able to differentiate between each state.

Application of hanging drop technique for stem cell differentiation and cytotoxicity studies.

PubMed

Banerjee, Meenal; Bhonde, Ramesh R

2006-05-01

The aim of our study is to explore the possibility of using an ancient method of culture technique- the hanging drop technique for stem cell differentiation and cytotoxicity testing. We demonstrate here a variety of novel applications of this age old technique not only to harness the differentiation potential of stem cells into specific lineages but also for cytotoxicity studies. Here we have prepared hanging drop cultures by placing 20 microl micro-drops of nutrient media and 10% Fetal Calf Serum (FCS) containing cells of interest on the lids of 60 mm dishes. Bottom plates of the dishes were filled with sterile Phosphate Buffer Saline (PBS) to avoid desiccation of samples. Lids were then placed on the bottom plates to achieve hanging drop cultures. We utilized this technique for cultivation of ciliated epithelia to study cytotoxicity and differentiation of bone marrow stromal cells. Most importantly the modified culture technique presented here is simple, economical and cost effective in terms of the time taken and the reagents required and are amenable to goal specific modification such as cytotoxicity testing. It is advantageous over the existing system in terms of retention of viability and functionality for longer duration and for providing three dimensional growth micro-environment making it useful for organotypic cultures and in vivo simulation.

Some failure modes and analysis techniques for terrestrial solar cell modules

NASA Technical Reports Server (NTRS)

Shumka, A.; Stern, K. H.

1978-01-01

Analysis data are presented on failed/defective silicon solar cell modules of various types and produced by different manufacturers. The failure mode (e.g., internal short and open circuits, output power degradation, isolation resistance degradation, etc.) are discussed in detail and in many cases related to the type of technology used in the manufacture of the modules; wherever applicable, appropriate corrective actions are recommended. Consideration is also given to some failure analysis techniques that are applicable to such modules, including X-ray radiography, capacitance measurement, cell shunt resistance measurement by the shadowing technique, steady-state illumination test station for module performance illumination, laser scanning techniques, and the SEM.

Conceptual Change Text: A Supplementary Material To Facilitate Conceptual Change in Electrochemical Cell Concepts.

ERIC Educational Resources Information Center

Yuruk, Nejla; Geban, Omer

The main purpose of the study was to investigate the effectiveness of conceptual change text (CCT) oriented instruction over traditionally designed instruction on students' understanding of electrochemical (galvanic and electrolytic) cell concepts. The subjects of the study consisted of 64 students from the two classes of a high school in Turkey.…

Biotechnology Apprenticeship for Secondary-Level Students: Teaching Advanced Cell Culture Techniques for Research.

ERIC Educational Resources Information Center

Lewis, Jennifer R.; Kotur, Mark S.; Butt, Omar; Kulcarni, Sumant; Riley, Alyssa A.; Ferrell, Nick; Sullivan, Kathryn D.; Ferrari, Mauro

2002-01-01

Discusses small-group apprenticeships (SGAs) as a method for introducing cell culture techniques to high school participants. Teaches cell culture practices and introduces advance imaging techniques to solve various biomedical engineering problems. Clarifies and illuminates the value of small-group laboratory apprenticeships. (Author/KHR)

The Effect of Supplementing Instruction with Conceptual Change Texts on Students' Conceptions of Electrochemical Cells

ERIC Educational Resources Information Center

Yuruk, Nejla

2007-01-01

The aim of this study was to investigate the effectiveness of instruction supplemented by conceptual change texts (CCTs) over traditional instruction on students' understanding of electrochemical (galvanic and electrolytic) cell concepts. The participants of the study consisted of 64 students from the two classes of a high school located in…

Microphotographs of cyanobacteria documenting the effects of various cell-lysis techniques

USGS Publications Warehouse

Rosen, Barry H.; Loftin, Keith A.; Smith, Christopher E.; Lane, Rachael F.; Keydel, Susan P.

2011-01-01

Cyanotoxins are a group of organic compounds biosynthesized intracellularly by many species of cyanobacteria found in surface water. The United States Environmental Protection Agency has listed cyanotoxins on the Safe Drinking Water Act's Contaminant Candidate List 3 for consideration for future regulation to protect public health. Cyanotoxins also pose a risk to humans and other organisms in a variety of other exposure scenarios. Accurate and precise analytical measurements of cyanotoxins are critical to the evaluation of concentrations in surface water to address the human health and ecosystem effects. A common approach to total cyanotoxin measurement involves cell membrane disruption to release the cyanotoxins to the dissolved phase followed by filtration to remove cellular debris. Several methods have been used historically, however no standard protocols exist to ensure this process is consistent between laboratories before the dissolved phase is measured by an analytical technique for cyanotoxin identification and quantitation. No systematic evaluation has been conducted comparing the multiple laboratory sample processing techniques for physical disruption of cell membrane or cyanotoxins recovery. Surface water samples collected from lakes, reservoirs, and rivers containing mixed assemblages of organisms dominated by cyanobacteria, as well as laboratory cultures of species-specific cyanobacteria, were used as part of this study evaluating multiple laboratory cell-lysis techniques in partnership with the U.S. Environmental Protection Agency. Evaluated extraction techniques included boiling, autoclaving, sonication, chemical treatment, and freeze-thaw. Both treated and untreated samples were evaluated for cell membrane integrity microscopically via light, epifluorescence, and epifluorescence in the presence of a DNA stain. The DNA stain, which does not permeate live cells with intact membrane structures, was used as an indicator for cyanotoxin release into the

The Modeling and Simulation of the Galvanic Coupling Intra-Body Communication via Handshake Channel

PubMed Central

Li, Maoyuan; Song, Yong; Li, Wansong; Wang, Guangfa; Bu, Tianpeng; Zhao, Yufei; Hao, Qun

2017-01-01

Intra-body communication (IBC) is a technology using the conductive properties of the body to transmit signal, and information interaction by handshake is regarded as one of the important applications of IBC. In this paper, a method for modeling the galvanic coupling intra-body communication via handshake channel is proposed, while the corresponding parameters are discussed. Meanwhile, the mathematical model of this kind of IBC is developed. Finally, the validity of the developed model has been verified by measurements. Moreover, its characteristics are discussed and compared with that of the IBC via single body channel. Our results indicate that the proposed method will lay a foundation for the theoretical analysis and application of the IBC via handshake channel. PMID:28420119

A novel histological technique for distinguishing between epithelial cells in forensic casework.

PubMed

French, Claire E V; Jensen, Cynthia G; Vintiner, Susan K; Elliot, Douglas A; McGlashan, Susan R

2008-06-10

There are a number of forensic cases in which the identification of the epithelial cell type from which DNA originated would provide important probative evidence. This study aimed to develop a technique using histological staining of fixed cells to distinguish between skin, buccal and vaginal epithelium. First, 11 different stains were screened on formalin-fixed, wax-embedded cells from five women. Samples were analysed qualitatively by examining staining patterns (colour) and morphology (absence or presence of nuclei). Three of the staining methods--Dane's, Csaba's and Ayoub-Shklar--were successful in distinguishing skin epithelial cells from buccal and vaginal. Second, cells were smeared directly onto slides, fixed with one of five fixatives and stained with one of the three stains mentioned above. Methanol fixation, coupled with the Dane's staining method, specific to keratin, was the only technique that distinguished between all three cell types. Skin cells stained magenta, red and orange and lacked nuclei; buccal cells stained predominantly orange-pink with red nuclei; while vaginal cells stained bright orange with orange nuclei and a blue extracellular hue. This staining pattern in vaginal cells was consistent in samples collected from 50 women aged between 18 and 67. Identification of cell type from unlabelled micrographs by 10 trained observers showed a mean success rate of 95%. The results of this study demonstrate that histological staining may provide forensic scientists with a technique for distinguishing between skin, buccal and vaginal epithelial cells and thus would enable more conclusive analyses when investigating sexual assault cases.

Antibacterial Ag/a-C nanocomposite coatings: The influence of nano-galvanic a-C and Ag couples on Ag ionization rates

NASA Astrophysics Data System (ADS)

Manninen, N. K.; Calderon, S.; Carvalho, I.; Henriques, M.; Cavaleiro, A.; Carvalho, S.

2016-07-01

Biofilm formation has been pointed as a major concern in different industrial applications, namely on biomedical implants and surgical instruments, which has prompted the development of new strategies for production of efficient antimicrobial surfaces. In this work, nano-galvanic couples were created to enhance the antibacterial properties of silver, by embedding it into amorphous carbon (a-C) matrix. The developed Ag/a-C nanocomposite coatings, deposited by magnetron sputtering, revealed an outstanding antibacterial activity against Staphylococcus epidermidis, promoting a total reduction in biofilm formation with no bacteria counts in all dilution. The open circuit potential (OCP) tests in 0.9% NaCl confirmed that a-C shows a positive OCP value, in contrast to Ag coating, thus enhancing the ionization of biocidal Ag+ due to the nano-galvanic couple activation. This result was confirmed by the inductively coupled plasma-optical emission spectroscopy (ICP-OES), which revealed a higher Ag ionization rate in the nanocomposite coating in comparison with the Ag coating. The surface of Ag/a-C and Ag coatings immersed in 0.9% NaCl were monitored by scanning electron microscopy (SEM) over a period of 24 h, being found that the Ag ionization determined by ICP-OES was accompanied by an Ag nanoparticles coalescence and agglomeration in Ag/a-C coating.

Optimization of Native and Formaldehyde iPOND Techniques for Use in Suspension Cells.

PubMed

Wiest, Nathaniel E; Tomkinson, Alan E

2017-01-01

The isolation of proteins on nascent DNA (iPOND) technique developed by the Cortez laboratory allows a previously unparalleled ability to examine proteins associated with replicating and newly synthesized DNA in mammalian cells. Both the original, formaldehyde-based iPOND technique and a more recent derivative, accelerated native iPOND (aniPOND), have mostly been performed in adherent cell lines. Here, we describe modifications to both protocols for use with suspension cell lines. These include cell culture, pulse, and chase conditions that optimize sample recovery in both protocols using suspension cells and several key improvements to the published aniPOND technique that reduce sample loss, increase signal to noise, and maximize sample recovery. Additionally, we directly and quantitatively compare the iPOND and aniPOND protocols to test the strengths and limitations of both. Finally, we present a detailed protocol to perform the optimized aniPOND protocol in suspension cell lines. © 2017 Elsevier Inc. All rights reserved.

Electrochemical fluorination for processing of used nuclear fuel

DOEpatents

Garcia-Diaz, Brenda L.; Martinez-Rodriguez, Michael J.; Gray, Joshua R.; Olson, Luke C.

2016-07-05

A galvanic cell and methods of using the galvanic cell is described for the recovery of uranium from used nuclear fuel according to an electrofluorination process. The galvanic cell requires no input energy and can utilize relatively benign gaseous fluorinating agents. Uranium can be recovered from used nuclear fuel in the form of gaseous uranium compound such as uranium hexafluoride, which can then be converted to metallic uranium or UO.sub.2 and processed according to known methodology to form a useful product, e.g., fuel pellets for use in a commercial energy production system.

Biotechnology Apprenticeship for Secondary-Level Students: Teaching Advanced Cell Culture Techniques for Research

ERIC Educational Resources Information Center

Lewis, Jennifer R.; Kotur, Mark S.; Butt, Omar; Kulcarni, Sumant; Riley, Alyssa A.; Ferrell, Nick; Sullivan, Kathryn D.; Ferrari, Mauro

2002-01-01

The purpose of this article is to discuss "small-group apprenticeships (SGAs)" as a method to instruct cell culture techniques to high school participants. The study aimed to teach cell culture practices and to introduce advanced imaging techniques to solve various biomedical engineering problems. Participants designed and completed experiments…

Galvanic reduction of uranium(III) chloride from LiCl-KCl eutectic salt using gadolinium metal

NASA Astrophysics Data System (ADS)

Bagri, Prashant; Zhang, Chao; Simpson, Michael F.

2017-09-01

The drawdown of actinides is an important unit operation to enable the recycling of electrorefiner salt and minimization of waste. A new method for the drawdown of actinide chlorides from LiCl-KCl molten salt has been demonstrated here. Using the galvanic interaction between the Gd/Gd(III) and U/U(III) redox reactions, it is shown that UCl3 concentration in eutectic LiCl-KCl can be reduced from 8.06 wt.% (1.39 mol %) to 0.72 wt.% (0.12 mol %) in about an hour via plating U metal onto a steel basket. This is a simple process for returning actinides to the electrorefiner and minimizing their loss to the salt waste stream.

Stabilization/solidification of hot dip galvanizing ash using different binders.

PubMed

Vinter, S; Montanes, M T; Bednarik, V; Hrivnova, P

2016-12-15

This study focuses on solidification of hot dip-galvanizing ash with a high content of zinc and soluble substances. The main purpose of this paper is to immobilize these pollutants into a matrix and allow a safer way for landfill disposal of that waste. Three different binders (Portland cement, fly ash and coal fluidized-bed combustion ash) were used for the waste solidification. Effectiveness of the process was evaluated using leaching test according to EN 12457-4 and by using the variance analysis and the categorical multifactorial test. In the leaching test, four parameters were observed: pH, zinc concentration in leachate, and concentration of chlorides and dissolved substances in leachate. The acquired data was then processed using statistical software to find an optimal solidifying ratio of the addition of binder, water, and waste to the mixture, with the aim to fulfil the requirement for landfill disposal set by the Council Decision 2003/33/EC. The influence on the main observed parameters (relative amount of water and a binder) on the effectiveness of the used method and their influence of measured parameters was also studied. Copyright © 2016 Elsevier B.V. All rights reserved.

Influence of the doping type and level on the morphology of porous Si formed by galvanic etching

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pyatilova, O. V., E-mail: 5ilova87@gmail.com; Gavrilov, S. A.; Shilyaeva, Yu. I.

The formation of porous silicon (por-Si) layers by the galvanic etching of single-crystal Si samples (doped with boron or phosphorus) in an HF/C{sub 2}H{sub 5}OH/H{sub 2}O{sub 2} solution is investigated. The por-Si layers are analyzed by the capillary condensation of nitrogen and scanning electron microscopy (SEM). The dependences of the morphological characteristics of por-Si (pore diameter, specific surface area, pore volume, and thickness of the pore walls), which determine the por-Si combustion kinetics, on the dopant type and initial wafer resistivity are established.

Designing the Color of Hot-Dip Galvanized Steel Sheet Through Destructive Light Interference Using a Zn-Ti Liquid Metallic Bath

NASA Astrophysics Data System (ADS)

Levai, Gabor; Godzsák, Melinda; Török, Tamas I.; Hakl, Jozsef; Takáts, Viktor; Csik, Attila; Vad, Kalman; Kaptay, George

2016-07-01

The color of hot-dip galvanized steel sheet was adjusted in a reproducible way using a liquid Zn-Ti metallic bath, air atmosphere, and controlling the bath temperature as the only experimental parameter. Coloring was found only for samples cooled in air and dipped into Ti-containing liquid Zn. For samples dipped into a 0.15 wt pct Ti-containing Zn bath, the color remained metallic (gray) below a 792 K (519 °C) bath temperature; it was yellow at 814 K ± 22 K (541 °C ± 22 °C), violet at 847 K ± 10 K (574 °C ± 10 °C), and blue at 873 K ± 15 K (600 °C ± 15 °C). With the increasing bath temperature, the thickness of the adhered Zn-Ti layer gradually decreased from 52 to 32 micrometers, while the thickness of the outer TiO2 layer gradually increased from 24 to 69 nm. Due to small Al contamination of the Zn bath, a thin (around 2 nm) alumina-rich layer is found between the outer TiO2 layer and the inner macroscopic Zn layer. It is proven that the color change was governed by the formation of thin outer TiO2 layer; different colors appear depending on the thickness of this layer, mostly due to the destructive interference of visible light on this transparent nano-layer. A complex model was built to explain the results using known relationships of chemical thermodynamics, adhesion, heat flow, kinetics of chemical reactions, diffusion, and optics. The complex model was able to reproduce the observations and allowed making predictions on the color of the hot-dip galvanized steel sample, as a function of the following experimental parameters: temperature and Ti content of the Zn bath, oxygen content, pressure, temperature and flow rate of the cooling gas, dimensions of the steel sheet, velocity of dipping the steel sheet into the Zn-Ti bath, residence time of the steel sheet within the bath, and the velocity of its removal from the bath. These relationships will be valuable for planning further experiments and technologies on color hot-dip galvanization of steel

Treatment of model and galvanic waste solutions of copper(II) ions using a lignin/inorganic oxide hybrid as an effective sorbent.

PubMed

Ciesielczyk, Filip; Bartczak, Przemysław; Klapiszewski, Łukasz; Jesionowski, Teofil

2017-04-15

A study was made concerning the removal of copper(II) ions from model and galvanic waste solutions using a new sorption material consisting of lignin in combination with an inorganic oxide system. Specific physicochemical properties of the material resulted from combining the activity of the functional groups present in the structure of lignin with the high surface area of the synthesized oxide system (585m 2 /g). Analysis of the porous structure parameters, particle size and morphology, elemental composition and characteristic functional groups confirmed the effective synthesis of the new type of sorbent. A key element of the study was a series of tests of adsorption of copper(II) ions from model solutions. It was determined how the efficiency of the adsorption process was affected by the process time, mass of sorbent, concentration of adsorbate, pH and temperature. Potential regeneration of adsorbent, which provides the possibility of its reusing and recovering the adsorbed copper, was also analyzed. The sorption capacity of the material was measured (83.98mg/g), and the entire process was described using appropriate kinetic models. The results were applied to the design of a further series of adsorption tests, carried out on solutions of real sewage from a galvanizing plant. Copyright © 2017 Elsevier B.V. All rights reserved.

Changeability of tissue's magnetic remanence after galvanic-magnetostimulation in upper-back pain treatment.

PubMed

Dyszkiewicz, Andrzej Jan; Kępiński, Paweł; Połeć, Paweł; Chachulski, Damian; Nowak-Kostrzewska, Ewa

2015-11-01

Research was conducted on parametric profiles of healthy subjects and patients with cervico-brachial pain syndrome resulting from C4/5 and/or C5/6 discopathy, including magnetic remanence of tissues in marker points 1-12 (L+R) and functional parameters, and their subsequent change after treatment in group A, using method of push-pull galvanic magnetostimulation (GMT 2.0). GMT 2.0 device, comprised of one air solenoid and three galvanic solenoids in electrolytic tubs, was designed for push-pull magnetostimulation of the head, coupled with simultaneous stimulation of the limbs. Clinical trial was conducted in Outpatient Private Clinic "VIS" under the auspices of Silesian Higher Medical School in Katowice, Poland. 55 subjects participated in the study: control group K consisted of 23 healthy individuals, whereas 33 patients in group A were treated using GMT 2.0. Only patients in group A were treated with GMT 2.0 during 40-min sessions over a period of 10 days. Parametric profile of the patients was defined using various measurements: electronic SFTR test (C-Th-shoulders), HR, RR, BDI and VAS tests, magnetic remanence in marker points 1-12 (L+R) and blood parameters: HB, ER, CREA, BIL, K(+), Na(+), Cl(-) Fe(2+), Ca(2+) and Mg(2+). There was a significant reduction in pain (VAS), increase in the range of motion (SFTR), lower depression symptoms (BDI), slower heart rate (HR), lower blood pressure (RR), greater concentration of Mg(2+), K(+), Ca(2+)ions and reduction in the concentration of BIL, CREA Fe(2+) after GMT 2.0 treatment in group A. Evaluation of magnetic remanence in marker points M1-12 (L+R) initially showed higher values in group K, which after treatment were normalized to values similar to those in group K. GMT 2.0 treatment in group A resulted in normalization of magnetic remanence, synergically with increased range of motion (SFTR test), decreased HR and RR parameters, smaller depressive trends (BDI test), as well as increased ion levels (K(+), Mg(2+), Ca(2

Influence of Minor Alloying Elements on Selective Oxidation and Reactive Wetting of CMnSi TRIP Steel during Hot Dip Galvanizing

NASA Astrophysics Data System (ADS)

Cho, Lawrence; Kim, Myung Soo; Kim, Young Ha; De Cooman, Bruno C.

2014-09-01

The influence of the addition of minor alloying elements on the selective oxidation and the reactive wetting of CMnSi transformation-induced plasticity (TRIP) steels was studied by means of galvanizing simulator tests. Five TRIP steels containing small alloying additions of Cr, Ni, Ti, Cu, and Sn were investigated. After intercritical annealing (IA) at 1093 K (820 °C) in a N2 + 5 pct H2 gas atmosphere with a dew point of 213 K (-60 °C), two types of oxides were formed on the strip surface: Mn-rich xMnO·SiO2 ( x > 1.5) and Si-rich xMnO·SiO2 ( x < 0.3) oxides. The addition of the minor alloying elements changed the morphology of the Si-rich oxides from a continuous film to discrete islands and this improved the wettability by molten Zn. The improved wetting effect of the minor alloying elements was attributed to an increased area fraction of the surface where the oxides were thinner, enabling a direct unhindered reaction between Fe and the Al in the liquid Zn and the formation of the inhibition layer during the hot dip galvanizing. The addition of a small amount of Sn is shown to significantly decrease the density of Zn-coating defects on CMnSi TRIP steels.

Automatic voltage imbalance detector

DOEpatents

Bobbett, Ronald E.; McCormick, J. Byron; Kerwin, William J.

1984-01-01

A device for indicating and preventing damage to voltage cells such as galvanic cells and fuel cells connected in series by detecting sequential voltages and comparing these voltages to adjacent voltage cells. The device is implemented by using operational amplifiers and switching circuitry is provided by transistors. The device can be utilized in battery powered electric vehicles to prevent galvanic cell damage and also in series connected fuel cells to prevent fuel cell damage.

Cell Seeding Densities in Autologous Chondrocyte Implantation Techniques for Cartilage Repair.

PubMed

Foldager, Casper Bindzus; Gomoll, Andreas H; Lind, Martin; Spector, Myron

2012-04-01

Cartilage repair techniques have been among the most intensively investigated treatments in orthopedics for the past decade, and several different treatment modalities are currently available. Despite the extensive research effort within this field, the generation of hyaline cartilage remains a considerable challenge. There are many parameters attendant to each of the cartilage repair techniques that can affect the amount and types of reparative tissue generated in the cartilage defect, and some of the most fundamental of these parameters have yet to be fully investigated. For procedures in which in vitro-cultured autologous chondrocytes are implanted under a periosteal or synthetic membrane cover, or seeded onto a porous membrane or scaffold, little is known about how the number of cells affects the clinical outcome. Few published clinical studies address the cell seeding density that was employed. The principal objective of this review is to provide an overview of the cell seeding densities used in cell-based treatments currently available in the clinic for cartilage repair. Select preclinical studies that have informed the use of specific cell seeding densities in the clinic are also discussed.

Effect of Mg on the Microstructure and Corrosion Resistance of the Continuously Hot-Dip Galvanizing Zn-Mg Coating

PubMed Central

Dong, Anping; Li, Baoping; Lu, Yanling; Zhu, Guoliang; Xing, Hui; Shu, Da; Sun, Baode; Wang, Jun

2017-01-01

The microstructure of continuously hot-dip galvanizing Zn-Mg coating was investigated in order to obtain the mechanism of the effects of Mg on the corrosion resistance. In this paper, the vertical section of the Zn-0.20 wt % Al-Mg ternary phase diagram near the Al-low corner was calculated. The results indicates that the phase composition of the Zn-0.20 wt % Al-Mg ternary phase diagram near the Al-low corner is the same as Zn-Mg binary phase diagram, suggesting Al in the Zn-Mg (ZM) coatings mainly concentrates on the interfacial layer between the coating and steel substrate. The microstructure of continuously hot-dip galvanizing ZM coatings with 0.20 wt % Al containing 1.0–3.0 wt % Mg was investigated using tunneling electron microscopy (TEM). The morphology of Zn in the coating changes from bulk to strip and finally to mesh-like, and the MgZn2 changes from rod-like to mesh-like with the Mg content increasing. Al in the ZM coatings mainly segregates at the Fe2Al5 inhibition layer and the Mg added to the Zn bath makes this inhibition layer thinner and uneven. Compared to GI coating, the time of the first red rust appears increases by more than two-fold and expansion rate of red rust reduces by more than four-fold in terms of salt spray experiment. The ZM coating containing 2.0 wt % Mg has the best corrosion resistance. The enhanced corrosion resistance of ZM coatings mainly depends on different corrosion products. PMID:28829393

Effect of Mg on the Microstructure and Corrosion Resistance of the Continuously Hot-Dip Galvanizing Zn-Mg Coating.

PubMed

Dong, Anping; Li, Baoping; Lu, Yanling; Zhu, Guoliang; Xing, Hui; Shu, Da; Sun, Baode; Wang, Jun

2017-08-22

The microstructure of continuously hot-dip galvanizing Zn-Mg coating was investigated in order to obtain the mechanism of the effects of Mg on the corrosion resistance. In this paper, the vertical section of the Zn-0.20 wt % Al-Mg ternary phase diagram near the Al-low corner was calculated. The results indicates that the phase composition of the Zn-0.20 wt % Al-Mg ternary phase diagram near the Al-low corner is the same as Zn-Mg binary phase diagram, suggesting Al in the Zn-Mg (ZM) coatings mainly concentrates on the interfacial layer between the coating and steel substrate. The microstructure of continuously hot-dip galvanizing ZM coatings with 0.20 wt % Al containing 1.0-3.0 wt % Mg was investigated using tunneling electron microscopy (TEM). The morphology of Zn in the coating changes from bulk to strip and finally to mesh-like, and the MgZn₂ changes from rod-like to mesh-like with the Mg content increasing. Al in the ZM coatings mainly segregates at the Fe₂Al₅ inhibition layer and the Mg added to the Zn bath makes this inhibition layer thinner and uneven. Compared to GI coating, the time of the first red rust appears increases by more than two-fold and expansion rate of red rust reduces by more than four-fold in terms of salt spray experiment. The ZM coating containing 2.0 wt % Mg has the best corrosion resistance. The enhanced corrosion resistance of ZM coatings mainly depends on different corrosion products.

Biotechnology Apprenticeship for Secondary-Level Students: Teaching Advanced Cell Culture Techniques for Research

PubMed Central

Lewis, Jennifer R.; Kotur, Mark S.; Butt, Omar; Kulcarni, Sumant; Riley, Alyssa A.; Ferrell, Nick; Sullivan, Kathryn D.; Ferrari, Mauro

2002-01-01

The purpose of this article is to discuss small-group apprenticeships (SGAs) as a method to instruct cell culture techniques to high school participants. The study aimed to teach cell culture practices and to introduce advanced imaging techniques to solve various biomedical engineering problems. Participants designed and completed experiments using both flow cytometry and laser scanning cytometry during the 1-month summer apprenticeship. In addition to effectively and efficiently teaching cell biology laboratory techniques, this course design provided an opportunity for research training, career exploration, and mentoring. Students participated in active research projects, working with a skilled interdisciplinary team of researchers in a large research institution with access to state-of-the-art instrumentation. The instructors, composed of graduate students, laboratory managers, and principal investigators, worked well together to present a real and worthwhile research experience. The students enjoyed learning cell culture techniques while contributing to active research projects. The institution's researchers were equally enthusiastic to instruct and serve as mentors. In this article, we clarify and illuminate the value of small-group laboratory apprenticeships to the institution and the students by presenting the results and experiences of seven middle and high school participants and their instructors. PMID:12587031

Biotechnology apprenticeship for secondary-level students: teaching advanced cell culture techniques for research.

PubMed

Lewis, Jennifer R; Kotur, Mark S; Butt, Omar; Kulcarni, Sumant; Riley, Alyssa A; Ferrell, Nick; Sullivan, Kathryn D; Ferrari, Mauro

2002-01-01

The purpose of this article is to discuss small-group apprenticeships (SGAs) as a method to instruct cell culture techniques to high school participants. The study aimed to teach cell culture practices and to introduce advanced imaging techniques to solve various biomedical engineering problems. Participants designed and completed experiments using both flow cytometry and laser scanning cytometry during the 1-month summer apprenticeship. In addition to effectively and efficiently teaching cell biology laboratory techniques, this course design provided an opportunity for research training, career exploration, and mentoring. Students participated in active research projects, working with a skilled interdisciplinary team of researchers in a large research institution with access to state-of-the-art instrumentation. The instructors, composed of graduate students, laboratory managers, and principal investigators, worked well together to present a real and worthwhile research experience. The students enjoyed learning cell culture techniques while contributing to active research projects. The institution's researchers were equally enthusiastic to instruct and serve as mentors. In this article, we clarify and illuminate the value of small-group laboratory apprenticeships to the institution and the students by presenting the results and experiences of seven middle and high school participants and their instructors.

Effectiveness of Shield Termination Techniques Tested with TEM Cell and Bulk Current Injection

NASA Technical Reports Server (NTRS)

Bradley, Arthur T.; Hare, Richard J.

2009-01-01

This paper presents experimental results of the effectiveness of various shield termination techniques. Each termination technique is evaluated by two independent noise injection methods; transverse electromagnetic (TEM) cell operated from 3 MHz 400 MHz, and bulk current injection (BCI) operated from 50 kHz 400 MHz. Both single carrier and broadband injection tests were investigated. Recommendations as to how to achieve the best shield transfer impedance (i.e. reduced coupled noise) are made based on the empirical data. Finally, the noise injection techniques themselves are indirectly evaluated by comparing the results obtained from the TEM Cell to those from BCI.

Günter Blobel: Pioneer of molecular cell biology (1936-2018).

PubMed

2018-04-02

Günter Blobel was a scientific colossus who dedicated his career to understanding the mechanisms for protein sorting to membrane organelles. His monumental contributions established research paradigms for major arenas of molecular cell biology. For this work, he received many accolades, including the Nobel Prize in Medicine or Physiology in 1999. He was a scientist of extreme passion and a nurturing mentor for generations of researchers, imbuing them with his deep love of cell biology and galvanizing them to continue his scientific legacy. Günter passed away on February 18, 2018, at the age of 81. © 2018 Rockefeller University Press.

Evaluation of Galvanic Vestibular Stimulation System

NASA Technical Reports Server (NTRS)

Kofman, I. S.; Warren, E.; DeSoto, R.; Moroney, G.; Chastain, J.; De Dios, Y. E.; Gadd, N.; Taylor, L.; Peters, B. T.; Allen, E.;

Vestibular evoked myogenic potential (VEMP) with galvanic stimulation in normal subjects.

PubMed

Cunha, Luciana Cristina Matos; Labanca, Ludimila; Tavares, Maurício Campelo; Gonçalves, Denise Utsch

2014-01-01

The vestibular evoked myogenic potential (VEMP) generated by galvanic vestibular stimulation (GVS) is related to the vestibulo-spinal pathway. The response recorded from soleus muscle is biphasic with onset of short latency (SL) component around 60 ms and medium latency (ML) component around 100 ms. The first component reflects otolith function (sacule and utricle) and the last deals with semicircular canals. To describe VEMP generated by GVS. In this cross-sectional clinical study, VEMP was generated by 2 mA/400 ms binaural GVS, frequency of 5-6 ms that was recorded from soleus muscles of 13 healthy adults, mean age 56 years. The subjects remained standing, head turned contralateral to the GVS applied to the mastoid. Thirty GVS were applied to the mastoid in the position cathode right anode left, followed by 30 in inverted position. SL and ML were measured. SL and ML components were recorded from both legs of all participants and were similar. The average of SL component was 54 ms and of ML was 112 ms. The components SL and ML of the VEMP response in soleus were reproducible and are useful measures of vestibular-spinal function.

Galvanic Tongue Stimulation Inhibits Five Basic Tastes Induced by Aqueous Electrolyte Solutions.

PubMed

Aoyama, Kazuma; Sakurai, Kenta; Sakurai, Satoru; Mizukami, Makoto; Maeda, Taro; Ando, Hideyuki

2017-01-01

Galvanic tongue stimulation (GTS) modulates taste sensation. However, the effect of GTS is contingent on the electrode polarity in the proximity of the tongue. If an anodal electrode is attached in the proximity of the tongue, an electrical or metallic taste is elicited. On the other hand, if only cathodal electrode is attached in the proximity of the tongue, the salty taste, which is induced by electrolyte materials, is inhibited. The mechanism of this taste inhibition is not adequately understood. In this study, we aim to demonstrate that the inhibition is cause by ions, which elicit taste and which migrate from the taste sensors on the tongue by GTS. We verified the inhibitory effect of GTS on all five basic tastes induced by electrolyte materials. This technology is effective for virtual reality systems and interfaces to support dietary restrictions. Our findings demonstrate that cathodal-GTS inhibits all the five basic tastes. The results also support our hypothesis that the effects of cathodal-GTS are caused by migrating tasting ions in the mouth.

Extracranial glioblastoma diagnosed by examination of pleural effusion using the cell block technique: case report.

PubMed

Hori, Yusuke S; Fukuhara, Toru; Aoi, Mizuho; Oda, Kazunori; Shinno, Yoko

2018-06-01

Metastatic glioblastoma is a rare condition, and several studies have reported the involvement of multiple organs including the lymph nodes, liver, and lung. The lung and pleura are reportedly the most frequent sites of metastasis, and diagnosis using less invasive tools such as cytological analysis with fine needle aspiration biopsy is challenging. Cytological analysis of fluid specimens tends to be negative because of the small number of cells obtained, whereas the cell block technique reportedly has higher sensitivity because of a decrease in cellular dispersion. Herein, the authors describe a patient with a history of diffuse astrocytoma who developed intractable, progressive accumulation of pleural fluid. Initial cytological analysis of the pleural effusion obtained by thoracocentesis was negative, but reanalysis using the cell block technique revealed the presence of glioblastoma cells. This is the first report to suggest the effectiveness of the cell block technique in the diagnosis of extracranial glioblastoma using pleural effusion. In patients with a history of glioma, the presence of extremely intractable pleural effusion warrants cytological analysis of the fluid using this technique in order to initiate appropriate chemotherapy.

Making Classical Conditioning Understandable through a Demonstration Technique.

ERIC Educational Resources Information Center

Gibb, Gerald D.

1983-01-01

One lemon, an assortment of other fruits and vegetables, a tennis ball, and a Galvanic Skin Response meter are needed to implement this approach to teaching about classical conditioning in introductory psychology courses. (RM)

Electrochemistry and speciation of Au(+) in a deep eutectic solvent: growth and morphology of galvanic immersion coatings.

PubMed

Ballantyne, Andrew D; Forrest, Gregory C H; Frisch, Gero; Hartley, Jennifer M; Ryder, Karl S

2015-11-11

In this study we compare the electrochemical and structural properties of three gold salts AuCl, AuCN and KAu(CN)2 in a Deep Eutectic Solvent (DES) electrolyte (Ethaline 200) in order to elucidate factors affecting the galvanic deposition of gold coatings on nickel substrates. A chemically reversible diffusion limited response was observed for AuCl, whereas AuCN and KAu(CN)2 showed much more complicated, kinetically limited responses. Galvanic exchange reactions were performed on nickel substrates from DES solutions of the three gold salts; the AuCN gave a bright gold coating, the KAu(CN)2 solution give a visibly thin coating, whilst the coating from AuCl was dull, friable and poorly adhesive. This behaviour was rationalised by the differing speciation for each of these compounds, as evidenced by EXAFS methods. Analysis of EXAFS data shows that AuCl forms the chlorido-complex [AuCl2](-), AuCN forms a mixed [AuCl(CN)](-) species, whereas KAu(CN)2 maintains its [Au(CN)2](-) structure. The more labile Cl(-) enables easier reduction of Au when compared to the tightly bound cyanide species, hence leading to slower kinetics of deposition and differing electrochemical behaviour. We conclude that metal speciation in DESs is a function of the initial metal salt and that this has a strong influence on the mechanism and rate of growth, as well as on the morphology of the metal deposit obtained. In addition, these coatings are also extremely promising from a technological perspective as Electroless Nickel Immersion Gold (ENIG) finishes in the printed circuit board (PCB) industry, where the elimination of acid in gold plating formulation could potentially lead to more reliable coatings. Consequently, these results are both significant and timely.

Highly Tunable Hollow Gold Nanospheres: Gaining Size Control and Uniform Galvanic Exchange of Sacrificial Cobalt Boride Scaffolds.

PubMed

Lindley, Sarah A; Cooper, Jason K; Rojas-Andrade, Mauricio D; Fung, Victoria; Leahy, Conor J; Chen, Shaowei; Zhang, Jin Z

2018-04-18

In principle, the diameter and surface plasmon resonance (SPR) frequency of hollow metal nanostructures can be independently adjusted, allowing the formation of targeted photoactivated structures of specific size and optical functionality. Although tunable SPRs have been reported for various systems, the shift in SPR is usually concomitant with a change in particle size. As such, more advanced tunability, including constant diameter with varying SPR or constant SPR with varying diameter, has not been properly achieved experimentally. Herein, we demonstrate this advanced tunability with hollow gold nanospheres (HGNs). HGNs were synthesized through galvanic exchange using cobalt-based nanoparticles (NPs) as sacrificial scaffolds. Co 2 B NP scaffolds were prepared by sodium borohydride nucleation of aqueous cobalt chloride and characterized using UV-vis, dynamic light scattering, X-ray absorption spectroscopy, and X-ray photoelectron spectroscopy. Careful control over the size of the Co 2 B scaffold and its galvanic conversion is essential to realize fine control of the resultant HGN diameter and shell thickness. In pursuit of size control, we introduce B(OH) 4 - (the final product of NaBH 4 hydrolysis) as a growth agent to obtain hydrodynamic diameters ranging from ∼17-85 nm with relative standard deviation <3%. The highly monodisperse Co 2 B NPs were then used as scaffolds for the formation of HGNs. In controlling HGN shell thickness and uniformity, environmental oxygen was shown to affect both the structural and optical properties of the resultant gold shells. With careful control of these key factors, we demonstrate an HGN synthesis that enables independent variation of diameter and shell thickness, and thereby SPR, with unprecedented uniformity. The new synthesis method creates a truly tunable plasmonic nanostructure platform highly desirable for a wide range of applications, including sensing, catalysis, and photothermal therapy.

An Approach for Improvement of Carbon Fiber Technique to Study Cardiac Cell Contractility

NASA Astrophysics Data System (ADS)

Myachina, T.; Khokhlova, A.; Antsygin, I.; Lookin, O.

2018-05-01

The technologies to study cardiac cell mechanics in near-physiological conditions are limited. Carbon fiber (CF) technique is a unique tool to study single cardiomyocyte contractility. However, the CF adhesion to a cell is limited and it is difficult to control CF sliding occurred due to inappropriate adhesion. In this study, we present a CF adhesion quality index – a linear coefficient (slope) derived from “end-diastolic cell length - end-diastolic sarcomere length” relationship. Potential applicability of this index is demonstrated on isolated rat and guinea pig ventricular cardiomyocytes. Further improvement of the approach may help to increase the quality of the experimental data obtained by CF technique.

Research Techniques Made Simple: High-Throughput Sequencing of the T-Cell Receptor.

PubMed

Matos, Tiago R; de Rie, Menno A; Teunissen, Marcel B M

2017-06-01

High-throughput sequencing (HTS) of the T-cell receptor (TCR) is a rapidly advancing technique that allows sensitive and accurate identification and quantification of every distinct T-cell clone present within any biological sample. The relative frequency of each individual clone within the full T-cell repertoire can also be studied. HTS is essential to expand our knowledge on the diversity of the TCR repertoire in homeostasis or under pathologic conditions, as well as to understand the kinetics of antigen-specific T-cell responses that lead to protective immunity (i.e., vaccination) or immune-related disorders (i.e., autoimmunity and cancer). HTS can be tailored for personalized medicine, having the potential to monitor individual responses to therapeutic interventions and show prognostic and diagnostic biomarkers. In this article, we briefly review the methodology, advances, and limitations of HTS of the TCR and describe emerging applications of this technique in the field of investigative dermatology. We highlight studying the pathogenesis of T cells in allergic dermatitis and the application of HTS of the TCR in diagnosing, detecting recurrence early, and monitoring responses to therapy in cutaneous T-cell lymphoma. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

The role of printing techniques for large-area dye sensitized solar cells

NASA Astrophysics Data System (ADS)

Mariani, Paolo; Vesce, Luigi; Di Carlo, Aldo

2015-10-01

The versatility of printing technologies and their intrinsic ability to outperform other techniques in large-area deposition gives scope to revolutionize the photovoltaic (PV) manufacturing field. Printing methods are commonly used in conventional silicon-based PVs to cover part of the production process. Screen printing techniques, for example, are applied to deposit electrical contacts on the silicon wafer. However, it is with the advent of third generation PVs that printing/coating techniques have been extensively used in almost all of the manufacturing processes. Among all the third generation PVs, dye sensitized solar cell (DSSC) technology has been developed up to commercialization levels. DSSCs and modules can be fabricated by adopting all of the main printing techniques on both rigid and flexible substrates. This allows an easy tuning of cell/module characteristics to the desired application. Transparency, colour, shape, layout and other DSSC’s features can be easily varied by changing the printing parameters and paste/ink formulations used in the printing process. This review focuses on large-area printing/coating technologies for the fabrication of DSSCs devices. The most used and promising techniques are presented underlining the process parameters and applications.

On The Effect Of Zinc Melt Composition On The Structure Of Hot-Dip Galvanized Coatings

NASA Astrophysics Data System (ADS)

Konidaris, S.; Pistofidis, N.; Vourlias, G.; Pavlidou, E.; Stergiou, A.; Stergioudis, G.; Polychroniadis, E. K.

2007-04-01

Zinc hot-dip galvanizing is an effective method for the corrosion protection of ferrous materials. A way of improving the results is through the addition of various elements in the zinc melt. In the present work the effect of Ni, Bi, Cr, Mn, Se and Si at concentration of 0.5 or 1.5 wt.% was examined. Coupons of carbon steel St-37 were coated with zinc containing the above-mentioned elements and were exposed in a Salt Spray Chamber (SSC). The micro structure of these coatings was examined with SEM and XRD. In every case the usual morphology was observed, while differences at the thickness and the crystal size of each layer were induced. However the alloying elements were present in the coating affecting its reactivity and, at least in the case of Mn and Cr, improving corrosion resistance.

Cell-flow technique.

PubMed

Hess, George P; Lewis, Ryan W; Chen, Yongli

2014-10-01

Various devices have been used to flow neurotransmitter solutions over cells containing receptors (e.g., ligand-gated ion channels) for whole-cell current recordings. With many of the devices, the orientation between the porthole of the flow device and the cell is not maintained absolutely constant. Orientation is critical for reproducibility in kinetic experiments. To be able to change the composition of the flowing solution during an experiment and still maintain a constant orientation, we use the cell-flow device described here. A peristaltic pump, a stainless steel U-tube, two different sizes of peristaltic tubing, and a solenoid valve are required to create a simple solution exchange system that can rapidly apply and remove solutions over the surface of a cell in tens of milliseconds. This system allows one to test multiple conditions on a cell containing the receptor of interest while constantly "washing" the cell with extracellular buffer solution between experimental applications. The use of the solenoid valve allows for the application of solutions to be precisely timed and controlled by a computer during electrophysiological current recording. © 2014 Cold Spring Harbor Laboratory Press.

Evanescent field microscopy techniques for studying dynamics at the surface of living cells

NASA Astrophysics Data System (ADS)

Sund, Susan E.

This thesis presents two distinct optical microscopy techniques for applications in cell biophysics: (a)the extension to living cells of an established technique, total internal reflection/fluorescence recovery after photobleaching (TIR/FRAP) for the first time in imaging mode; and (b)the novel development of polarized total internal reflection fluorescence (p- TIRF) to study membrane orientation in living cells. Although reversible chemistry is crucial to dynamical processes in living cells, relatively little is known about the relevant chemical kinetic rates in vivo. TIR/FRAP, an established technique which can measure reversible biomolecular kinetic rates at surfaces, is extended here to measure kinetic parameters of microinjected rhodamine actin at the cytofacial surface of the plasma membrane of living cultured smooth muscle cells. For the first time, spatial imaging (with a CCD camera) is used in conjunction with TIR/FRAP. TIR/FRAP imaging allows production of spatially resolved images of kinetic data, and calculation of correlation distances, cell-wide gradients, and kinetic parameter dependence on initial fluorescence intensity. In living cells, membrane curvature occurs both in easily imaged large scale morphological features, and also in less visualizable submicroscopic regions of activity such as endocytosis, exocytosis, and cell surface ruffling. A fluorescence microscopic method, p-TIRF, is introduced here to visualize such regions. The method is based on fluorescence of the oriented membrane probe diI- C18-(3) (diI) excited by evanescent field light polarized either perpendicular or parallel to the plane of the substrate coverslip. The excitation efficiency from each polarization depends on the membrane orientation, and thus the ratio of the observed fluorescence excited by these two polarizations vividly shows regions of microscopic and submicroscopic curvature of the membrane. A theoretical background of the technique and experimental verifications

Fos Expression in Neurons of the Rat Vestibulo-Autonomic Pathway Activated by Sinusoidal Galvanic Vestibular Stimulation

PubMed Central

Holstein, Gay R.; Friedrich Jr., Victor L.; Martinelli, Giorgio P.; Ogorodnikov, Dmitri; Yakushin, Sergei B.; Cohen, Bernard

2012-01-01

The vestibular system sends projections to brainstem autonomic nuclei that modulate heart rate and blood pressure in response to changes in head and body position with regard to gravity. Consistent with this, binaural sinusoidally modulated galvanic vestibular stimulation (sGVS) in humans causes vasoconstriction in the legs, while low frequency (0.02–0.04 Hz) sGVS causes a rapid drop in heart rate and blood pressure in anesthetized rats. We have hypothesized that these responses occur through activation of vestibulo-sympathetic pathways. In the present study, c-Fos protein expression was examined in neurons of the vestibular nuclei and rostral ventrolateral medullary region (RVLM) that were activated by low frequency sGVS. We found c-Fos-labeled neurons in the spinal, medial, and superior vestibular nuclei (SpVN, MVN, and SVN, respectively) and the parasolitary nucleus. The highest density of c-Fos-positive vestibular nuclear neurons was observed in MVN, where immunolabeled cells were present throughout the rostro-caudal extent of the nucleus. c-Fos expression was concentrated in the parvocellular region and largely absent from magnocellular MVN. c-Fos-labeled cells were scattered throughout caudal SpVN, and the immunostained neurons in SVN were restricted to a discrete wedge-shaped area immediately lateral to the IVth ventricle. Immunofluorescence localization of c-Fos and glutamate revealed that approximately one third of the c-Fos-labeled vestibular neurons showed intense glutamate-like immunofluorescence, far in excess of the stain reflecting the metabolic pool of cytoplasmic glutamate. In the RVLM, which receives a direct projection from the vestibular nuclei and sends efferents to preganglionic sympathetic neurons in the spinal cord, we observed an approximately threefold increase in c-Fos labeling in the sGVS-activated rats. We conclude that localization of c-Fos protein following sGVS is a reliable marker for sGVS-activated neurons of the vestibulo

Investigation of diseases through red blood cells' shape using photoacoustic response technique

NASA Astrophysics Data System (ADS)

Biswas, Deblina; Gorey, Abhijeet; Chen, Goerge C. K.; Sharma, Norman; Vasudevan, Srivathsan

2015-03-01

Photoacoustic (PA) imaging is a non-invasive real-time technique, widely applied to many biomedical imaging studies in the recent years. While most of these studies have been focussed on obtaining an image after reconstruction, various features of time domain signal (e.g. amplitude, width, rise and relaxation time) would provide very high sensitivity in detecting morphological changes in cells during a biological study. Different haematological disorders (e.g., sickle cell anaemia, thalassemia) exhibit significant morphological cellular changes. In this context, this study explores the possibility of utilizing the developed photoacoustic response technique to apply onto blood samples. Results of our preliminary study demonstrate that there is a significant change in signal amplitude due to change in concentration of the blood. Thus it shows the sensitivity of the developed photoacoustic technique towards red blood cell count (related to haematological disease like anaemia). Subsequently, morphological changes in RBC (i.e. swollen and shrunk compared to normal RBC) induced by hypotonic and hypertonic solutions respectively were also experimented. The result shows a distinct change in PA signal amplitude. This would serve as a diagnostic signature for many future studies on cellular morphological disorders.

Graphene liquid cells for multi-technique analysis of biological cells in water environment

NASA Astrophysics Data System (ADS)

Matruglio, A.; Zucchiatti, P.; Birarda, G.; Marmiroli, B.; D'Amico, F.; Kocabas, C.; Kiskinova, M.; Vaccari, L.

2018-05-01

In-cell exploration of biomolecular constituents is the new frontier of cellular biology that will allow full access to structure-activity correlation of biomolecules, overcoming the limitations imposed by dissecting the cellular milieu. However, the presence of water, which is a very strong IR absorber and incompatible with the vacuum working conditions of all analytical methods using soft x-rays and electrons, poses severe constraint to perform important imaging and spectroscopic analyses under physiological conditions. Recent advances to separate the sample compartment in liquid cell are based on electron and photon transparent but molecular-impermeable graphene membranes. This strategy has opened a unique opportunity to explore technological materials under realistic operation conditions using various types of electron microscopy. However, the widespread of the graphene liquid cell applications is still impeded by the lack of well-established approaches for their massive production. We report on the first preliminary results for the fabrication of reproducible graphene liquid cells appropriate for the analysis of biological specimens in their natural hydrated environment with several crucial analytical techniques, namely FTIR microscopy, Raman spectroscopy, AFM, SEM and TEM.

A Timing Synchronizer System for Beam Test Setups Requiring Galvanic Isolation

NASA Astrophysics Data System (ADS)

Meder, Lukas Dominik; Emschermann, David; Frühauf, Jochen; Müller, Walter F. J.; Becker, Jürgen

2017-07-01

In beam test setups detector elements together with a readout composed of frontend electronics (FEE) and usually a layer of field-programmable gate arrays (FPGAs) are being analyzed. The FEE is in this scenario often directly connected to both the detector and the FPGA layer what in many cases requires sharing the ground potentials of these layers. This setup can become problematic if parts of the detector need to be operated at different high-voltage potentials, since all of the FPGA boards need to receive a common clock and timing reference for getting the readout synchronized. Thus, for the context of the compressed baryonic matter experiment a versatile timing synchronizer (TS) system was designed providing galvanically isolated timing distribution links over twisted-pair cables. As an electrical interface the so-called timing data processing board FPGA mezzanine card was created for being mounted onto FPGA-based advanced mezzanine cards for mTCA.4 crates. The FPGA logic of the TS system connects to this card and can be monitored and controlled through IPBus slow-control links. Evaluations show that the system is capable of stably synchronizing the FPGA boards of a beam test setup being integrated into a hierarchical TS network.

Microstructure and Properties of Lap Joint Between Aluminum Alloy and Galvanized Steel by CMT

NASA Astrophysics Data System (ADS)

Niu, Song; Chen, Su; Dong, Honggang; Zhao, Dongsheng; Zhang, Xiaosheng; Guo, Xin; Wang, Guoqiang

2016-05-01

Lap joining of 1-mm-thick Novelist AC 170 PX aluminum alloy to 1.2-mm-thick ST06 Z galvanized steel sheets for automotive applications was conducted by cold metal transfer advanced welding process with ER4043 and ER4047 filler wires. Under the optimized welding parameters with ER4043 filler wire, the tensile shear strength of joint was 189 MPa, reaching 89% of the aluminum alloy base metal. Microstructure and elemental distribution were characterized by optical metalloscope and electron probe microanalysis. The lap joints with ER4043 filler wire had smaller wetting angle and longer bonded line length with better wettability than with ER4047 filler wire during welding with same parameters. The needle-like Al-Fe-Si intermetallic compounds (IMCs) were spalled into the weld and brought negative effect to the tensile strength of joints. With increasing welding current, the needle-like IMCs grew longer and spread further into the weld, which would deteriorate the tensile shear strength.

In Situ Apparatus to Study Gas-Metal Reactions and Wettability at High Temperatures for Hot-Dip Galvanizing Applications

NASA Astrophysics Data System (ADS)

Koltsov, A.; Cornu, M.-J.; Scheid, J.

2018-02-01

The understanding of gas-metal reactions and related surface wettability at high temperatures is often limited due to the lack of in situ surface characterization. Ex situ transfers at low temperature between annealing furnace, wettability device, and analytical tools induce noticeable changes of surface composition distinct from the reality of the phenomena.Therefore, a high temperature wettability device was designed in order to allow in situ sample surface characterization by x-rays photoelectron spectroscopy after gas/metal and liquid metal/solid metal surface reactions. Such airless characterization rules out any contamination and oxidation of surfaces and reveals their real composition after heat treatment and chemical reaction. The device consists of two connected reactors, respectively, dedicated to annealing treatments and wettability measurements. Heat treatments are performed in an infrared lamp furnace in a well-controlled atmosphere conditions designed to reproduce gas-metal reactions occurring during the industrial recrystallization annealing of steels. Wetting experiments are carried out in dispensed drop configuration with the precise control of the deposited droplets kinetic energies. The spreading of drops is followed by a high-speed CCD video camera at 500-2000 frames/s in order to reach information at very low contact time. First trials have started to simulate phenomena occurring during recrystallization annealing and hot-dip galvanizing on polished pure Fe and FeAl8 wt.% samples. The results demonstrate real surface chemistry of steel samples after annealing when they are put in contact with liquid zinc alloy bath during hot-dip galvanizing. The wetting results are compared to literature data and coupled with the characterization of interfacial layers by FEG-Auger. It is fair to conclude that the results show the real interest of such in situ experimental setup for interfacial chemistry studies.

Enhanced Performance of Field-Effect Transistors Based on Black Phosphorus Channels Reduced by Galvanic Corrosion of Al Overlayers.

PubMed

Lee, Sangik; Yoon, Chansoo; Lee, Ji Hye; Kim, Yeon Soo; Lee, Mi Jung; Kim, Wondong; Baik, Jaeyoon; Jia, Quanxi; Park, Bae Ho

2018-06-06

Two-dimensional (2D)-layered semiconducting materials with considerable band gaps are emerging as a new class of materials applicable to next-generation devices. Particularly, black phosphorus (BP) is considered to be very promising for next-generation 2D electrical and optical devices because of its high carrier mobility of 200-1000 cm 2 V -1 s -1 and large on/off ratio of 10 4 to 10 5 in field-effect transistors (FETs). However, its environmental instability in air requires fabrication processes in a glovebox filled with nitrogen or argon gas followed by encapsulation, passivation, and chemical functionalization of BP. Here, we report a new method for reduction of BP-channel devices fabricated without the use of a glovebox by galvanic corrosion of an Al overlayer. The reduction of BP induced by an anodic oxidation of Al overlayer is demonstrated through surface characterization of BP using atomic force microscopy, Raman spectroscopy, and X-ray photoemission spectroscopy along with electrical measurement of a BP-channel FET. After the deposition of an Al overlayer, the FET device shows a significantly enhanced performance, including restoration of ambipolar transport, high carrier mobility of 220 cm 2 V -1 s -1 , low subthreshold swing of 0.73 V/decade, and low interface trap density of 7.8 × 10 11 cm -2 eV -1 . These improvements are attributed to both the reduction of the BP channel and the formation of an Al 2 O 3 interfacial layer resulting in a high- k screening effect. Moreover, ambipolar behavior of our BP-channel FET device combined with charge-trap behavior can be utilized for implementing reconfigurable memory and neuromorphic computing applications. Our study offers a simple device fabrication process for BP-channel FETs with high performance using galvanic oxidation of Al overlayers.

The sensitivity of Galvanic Skin Response for assessing mental workload in Indonesia.

PubMed

Widyanti, Ari; Muslim, Khoirul; Sutalaksana, Iftikar Zahedi

2017-01-01

Objective measures have been shown to be equally sensitive in different cultures. However, these measures need special devices that are relatively expensive and need expertise to analyze the result. In Indonesia, there is a need for a sensitive and affordable mental workload measure. To evaluate the sensitivity of Galvanic Skin Response (GSR) in assessing mental workload in Indonesia. A total of 72 Indonesian students with normal visual capability. Participants were asked to work on visual memory search task with a secondary task of counting with three different levels of difficulty. GSR, Heart Rate Variability (HRV), and the NASA-TLX were administered prior to, during, and after the tasks. GSR measure was compared to NASA-TLX and HRV measures. Like the HRV, GSR showed to be sensitive in distinguishing rest and task condition significantly but not sensitive in distinguishing different levels of mental workload. In contrast, both the NASA-TLX and performance measure were sensitive in differentiating different levels of mental workload. GSR has potential as a simple, cost-effective tool for measuring mental workload in Indonesia.

Thermo-stoichiometric behavior of aluminum-nickel nanoheater particles fabricated by galvanic replacement reaction

NASA Astrophysics Data System (ADS)

Buckley, Jacqueline L.

2010-03-01

Al-Ni reactive nano-structures are gaining interest for various applications in aerospace, nano-manufacturing, and biomedical fields. However, nano-material behavior can vary from macro-scale. There has been no systematic study of Al-Ni exothermic reaction and intermetallic formation for nano-scale reactants. Therefore, this study aims to investigate deviations from the established Al-Ni phase diagram, with the premise that the intermetallic formation temperatures are expected to be lower for nano-reactants due to higher surface energy. Additionally, it is important to gain better understanding and control of the galvanic replacement reaction (GRR) fabrication method, which, in terms of producing Al-Ni bi-metallic nanoparticles, is a completely novel scheme. With an adapted phase diagram, intermetallic product and heat output of nanoparticles from any given stage of GRR process can be predicted. Al-Ni nanoparticles having ignitable Al-Ni ratios were fabricated via GRR method. Effects of composition and temperature on intermetallic formation were studied by in-situ XRD analysis. Effects of environment and heating rate on the Al-Ni exothermic reaction were also investigated.

The effect of zinc thickness on corrosion film breakdown of Colombian galvanized steel

NASA Astrophysics Data System (ADS)

Sandoval-Amador, A.; E Torres Ramirez, J.; Cabrales-Villamizar, P. A.; Laverde Cataño, D.; Y Peña-Ballesteros, D.

2017-12-01

This work studies the corrosion behaviour of Colombian galvanized steel in solutions of chloride and sulphate ions. The effect of the thickness and exposure time on the film’s breakdown susceptibility and protectiveness of the corrosion products were studied using potentiodynamic polarization curves and electrochemical impedance spectroscopy. The corrosion products were analysed using SEM-EDS and XRD. The samples with a higher thickness level in the zinc film (Z180) have the lowest corrosion rate. In this case, one of the products that was formed by the chemical reactions that occurred was Zinc hydroxide, which exhibits a passive behaviour as observed in the Pourbaix curves of the obtained potentials and in how the different Ph levels of the solutions worked. The sheets with the highest thickness (Z180) had the best performance, since at the end of the study they showed the least amount of damage on the surface of the zinc layer. This is because the thickness of the zinc layer favours the formation of simonkolleite, which is the corrosion product that protects the material under the conditions of the study.

CellML and associated tools and techniques.

PubMed

Garny, Alan; Nickerson, David P; Cooper, Jonathan; Weber dos Santos, Rodrigo; Miller, Andrew K; McKeever, Steve; Nielsen, Poul M F; Hunter, Peter J

2008-09-13

We have, in the last few years, witnessed the development and availability of an ever increasing number of computer models that describe complex biological structures and processes. The multi-scale and multi-physics nature of these models makes their development particularly challenging, not only from a biological or biophysical viewpoint but also from a mathematical and computational perspective. In addition, the issue of sharing and reusing such models has proved to be particularly problematic, with the published models often lacking information that is required to accurately reproduce the published results. The International Union of Physiological Sciences Physiome Project was launched in 1997 with the aim of tackling the aforementioned issues by providing a framework for the modelling of the human body. As part of this initiative, the specifications of the CellML mark-up language were released in 2001. Now, more than 7 years later, the time has come to assess the situation, in particular with regard to the tools and techniques that are now available to the modelling community. Thus, after introducing CellML, we review and discuss existing editors, validators, online repository, code generators and simulation environments, as well as the CellML Application Program Interface. We also address possible future directions including the need for additional mark-up languages.

Gene Profiling Technique to Accelerate Stem Cell Therapies for Eye Diseases

MedlinePlus

... like RPE. They also use a technique called quantitative RT-PCR to measure the expression of genes ... higher in iPS cells than mature RPE. But quantitative RT-PCR only permits the simultaneous measurement of ...

Isolated Capsulorhexis Flap Technique in Femtosecond Laser-Assisted Cataract Surgery to Protect the Corneal Endothelial Cells.

PubMed

Li, Shaowei; Chen, Xu; Zhao, Jun; Xu, Man; Yu, Zhouxing

2017-12-18

To present a novel technique that using capsulorhexis flap to protect corneal endothelial cells during femtosecond laser-assisted cataract surgery. During the procedure, an isolated capsulorhexis flap was used to lift it up carefully by using OVD until the flap attached to the corneal inner layer. It kept steady during the phaco phase, and been removed by I/A tip after intraocular lens implantation. In our pilot study, the damage to the corneal endothelial cells from the phacoemulsification procedure were no more than the traditional phaco procedure, even femtosecond laser assisted cataract surgery. Isolated capsulorhexis flap technique initiate a new approach to protect the endothelial cell. It is a simple technique with a short learning curve, but still need a further investigation to prove the protection of corneal endothelial cells.

Can cognitive processes help explain the success of instructional techniques recommended by behavior analysts?

NASA Astrophysics Data System (ADS)

Markovits, Rebecca A.; Weinstein, Yana

2018-01-01

The fields of cognitive psychology and behavior analysis have undertaken separate investigations into effective learning strategies. These studies have led to several recommendations from both fields regarding teaching techniques that have been shown to enhance student performance. While cognitive psychology and behavior analysis have studied student performance independently from their different perspectives, the recommendations they make are remarkably similar. The lack of discussion between the two fields, despite these similarities, is surprising. The current paper seeks to remedy this oversight in two ways: first, by reviewing two techniques recommended by behavior analysts—guided notes and response cards—and comparing them to their counterparts in cognitive psychology that are potentially responsible for their effectiveness; and second, by outlining some other areas of overlap that could benefit from collaboration. By starting the discussion with the comparison of two specific recommendations for teaching techniques, we hope to galvanize a more extensive collaboration that will not only further the progression of both fields, but also extend the practical applications of the ensuing research.

SIMSISH Technique Does Not Alter the Apparent Isotopic Composition of Bacterial Cells

PubMed Central

Chapleur, Olivier; Wu, Ting-Di; Guerquin-Kern, Jean-Luc; Mazéas, Laurent; Bouchez, Théodore

2013-01-01

In order to identify the function of uncultured microorganisms in their environment, the SIMSISH method, combining in situ hybridization (ISH) and nanoscale secondary ion mass spectrometry (nanoSIMS) imaging, has been proposed to determine the quantitative uptake of specific labelled substrates by uncultured microbes at the single cell level. This technique requires the hybridization of rRNA targeted halogenated DNA probes on fixed and permeabilized microorganisms. Exogenous atoms are introduced into cells and endogenous atoms removed during the experimental procedures. Consequently differences between the original and the apparent isotopic composition of cells may occur. In the present study, the influence of the experimental procedures of SIMSISH on the isotopic composition of carbon in E. coli cells was evaluated with nanoSIMS and compared to elemental analyser-isotopic ratio mass spectrometer (EA-IRMS) measurements. Our results show that fixation and hybridization have a very limited, reproducible and homogeneous influence on the isotopic composition of cells. Thereby, the SIMSISH procedure minimizes the contamination of the sample by exogenous atoms, thus providing a means to detect the phylogenetic identity and to measure precisely the carbon isotopic composition at the single cell level. This technique was successfully applied to a complex sample with double bromine – iodine labelling targeting a large group of bacteria and a specific archaea to evaluate their specific 13C uptake during labelled methanol anaerobic degradation. PMID:24204855

Techniques for early diagnosis of oral squamous cell carcinoma: Systematic review

PubMed Central

Carreras-Torras, Clàudia

2015-01-01

Background and objectives The diagnosis of early oral potentially malignant disorders (OPMD) and oral squamous cell carcinoma (OSCC) is of paramount clinical importance given the mortality rate of late stage disease. The aim of this study is to review the literature to assess the current situation and progress in this area. Material and Methods A search in Cochrane and PubMed (January 2006 to December 2013) has been used with the key words “squamous cell carcinoma”, “early diagnosis” “oral cavity”, “Potentially Malignant Disorders” y “premalignant lesions”. The inclusion criteria were the use of techniques for early diagnosis of OSCC and OPMD, 7 years aged articles and publications written in English, French or Spanish. The exclusion criteria were case reports and studies in other languages. Results Out of the 89 studies obtained initially from the search 60 articles were selected to be included in the systematic review: 1 metaanalysis, 17 systematic reviews, 35 prospective studies, 5 retrospective studies, 1 consensus and 1 semi-structured interviews. Conclusions The best diagnostic technique is that which we have sufficient experience and training. Definitely tissue biopsy and histopathological examination should remain the gold standard for oral cancer diagnose. In this systematic review it has not been found sufficient scientific evidence on the majority of proposed techniques for early diagnosis of OSCC, therefore more extensive and exhaustive studies are needed. Key words: Squamous cell carcinoma, early diagnosis, oral cavity, potentially malignant disorders, premalignant lesions. PMID:25662554

Study on the wiping gas jet in continuous galvanizing line

NASA Astrophysics Data System (ADS)

Kweon, Yong-Hun; Kim, Heuy-Dong

2011-09-01

In the continuous hot-dip galvanizing process, the gas-jet wiping is used to control the coating thickness of moving steel strip. The high speed gas-jet discharged from the nozzle slot impinges on the strip, and at this moment, wipes the liquid coating layer dragged by a moving strip. The coating thickness is generally influenced on the flow characteristics of wiping gas-jet such as the impinging pressure distribution, pressure gradient and shear stress distribution on the surface of strip. The flow characteristics of wiping gas-jet mentioned above depends upon considerably both the process operating conditions such as the nozzle pressure, nozzle-to-strip distance and line speed, and the geometry of gas-jet wiping apparatus such as the height of nozzle slot. In the present study, the effect of the geometry of nozzle on the coating thickness is investigated with the help of a computational fluid dynamics method. The height of nozzle slot is varied in the range of 0.6mm to 1.7mm. A finite volume method (FVM) is employed to solve two-dimensional, steady, compressible Navier-Stokes equations. Based upon the results obtained, the effect of the height of nozzle slot in the gas-jet wiping process is discussed in detail. The computational results show that for a given standoff distance between the nozzle to the strip, the effective height of nozzle slot exists in achieving thinner coating thickness.

Galvanic corrosion between orthodontic wires and brackets in fluoride mouthwashes.

PubMed

Schiff, Nicolas; Boinet, Mickaël; Morgon, Laurent; Lissac, Michèle; Dalard, Francis; Grosgogeat, Brigitte

2006-06-01

The aim of this investigation was to determine the influence of fluoride in certain mouthwashes on the risk of corrosion through galvanic coupling of orthodontic wires and brackets. Two titanium alloy wires, nickel-titanium (NiTi) and copper-nickel-titanium (CuNiTi), and the three most commonly used brackets, titanium (Ti), iron-chromium-nickel (FeCrNi) and cobalt-chromium (CoCr), were tested in a reference solution of Fusayama-Meyer artificial saliva and in two commercially available fluoride (250 ppm) mouthwashes, Elmex and Meridol. Corrosion resistance was assessed by inductively coupled plasma-atomic emission spectrometry (ICP-MS), analysis of released metal ions, and a scanning electron microscope (SEM) study of the metal surfaces after immersion of different wire-bracket pairs in the test solutions. The study was completed by an electrochemical analysis. Meridol mouthwash, which contains stannous fluoride, was the solution in which the NiTi wires coupled with the different brackets showed the highest corrosion risk, while in Elmex mouthwash, which contains sodium fluoride, the CuNiTi wires presented the highest corrosion risk. Such corrosion has two consequences: deterioration in mechanical performance of the wire-bracket system, which would negatively affect the final aesthetic result, and the risk of local allergic reactions caused by released Ni ions. The results suggest that mouthwashes should be prescribed according to the orthodontic materials used. A new type of mouthwash for use during orthodontic therapy could be an interesting development in this field.

Teaching Electrochemistry in the General Chemistry Laboratory through Corrosion Exercises

ERIC Educational Resources Information Center

Sanders, Richard W.; Crettol, Gregory L.; Brown, Joseph D.; Plummer, Patrick T.; Schendorf, Tara M.; Oliphant, Alex; Swithenbank, Susan B.; Ferrante, Robert F.; Gray, Joshua P.

2018-01-01

Electrochemistry is primarily taught in first-year undergraduate courses through batteries; this lab focuses instead on corrosion to apply electrochemical concepts of electrolytes, standard reduction potentials, galvanic cells, and other chemistry concepts including Le Chatelier's Principle and Henry's Law. Students investigate galvanic corrosion…

Live cell and immuno-labeling techniques to study gravitational effects on single plant cells.

PubMed

Chebli, Youssef; Geitmann, Anja

2015-01-01

The constant force of gravity plays a primordial role in the ontogeny of all living organisms. Plants, for example, develop their roots and shoots in accordance with the direction of the gravitational vector. Any change in the magnitude and/or the direction of gravity has an important impact on the development of tissues and cells. In order to understand how the gravitational force affects plant cell growth and differentiation, we established two complementary experimental procedures with which the effect of hyper-gravity on single plant cell development can be assessed. The single model cell system we used is the pollen tube or male gametophyte which, because of its rapid growth behavior, is known for its instant response to external stresses. The physiological response of the pollen tube can be assessed in a quantitative manner based on changes in the composition and spatial distribution of its cell wall components and in the precisely defined pattern of its very dynamic cytoplasmic streaming. Here, we provide a detailed description of the steps required for the immuno-localization of various cell wall components using microwave-assisted techniques and we explain how live imaging of the intracellular traffic can be achieved under hyper-gravity conditions.

A study on the fabrication of superhydrophobic iron surfaces by chemical etching and galvanic replacement methods and their anti-icing properties

NASA Astrophysics Data System (ADS)

Li, Kunquan; Zeng, Xingrong; Li, Hongqiang; Lai, Xuejun

2015-08-01

Hierarchical structures on iron surfaces were constructed by means of chemical etching by hydrochloric acid (HCl) solution or the galvanic replacement by silver nitrate (AgNO3) solution. The superhydrophobic iron surfaces were successfully prepared by subsequent hydrophobic modification with stearic acid. The superhydrophobic iron surfaces were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and water contact angle (WCA). The effects of reactive concentration and time on the microstructure and the wetting behavior were investigated. In addition, the anti-icing properties of the superhydrophobic iron surfaces were also studied. The FTIR study showed that the stearic acid was chemically bonded onto the iron surface. With the HCl concentration increase from 4 mol/L to 8 mol/L, the iron surface became rougher with a WCA ranging from 127° to 152°. The AgNO3 concentration had little effect on the wetting behavior, but a high AgNO3 concentration caused Ag particle aggregates to transform from flower-like formations into dendritic crystals, owing to the preferential growth direction of the Ag particles. Compared with the etching method, the galvanic replacement method on the iron surface more favorably created roughness required for achieving superhydrophobicity. The superhydrophobic iron surface showed excellent anti-icing properties in comparison with the untreated iron. The icing time of water droplets on the superhydrophobic surface was delayed to 500 s, which was longer than that of 295 s for untreated iron. Meanwhile, the superhydrophobic iron surface maintained superhydrophobicity after 10 icing and de-icing cycles in cold conditions.

Effect of fabrication technique on direct methanol fuel cells designed to operate at low airflow

NASA Technical Reports Server (NTRS)

Valdez, T. I.; Narayanan, S. R.

2002-01-01

This study investigates the effects of catalyst ink constituents and MEA fabrication techniques on improving cell performance. Particular attention was focused on increasing the overall cell efficiency.

Detection of Infectious Bovine Rhinotracheitis and Bovine Viral Diarrhea Viruses in the Nasal Epithelial Cells by the Direct Immunofluorescence Technique

PubMed Central

Silim, A.; Elazhary, M.A.S.Y.

1983-01-01

Nasal epithelial cells were collected by cotton swabs for the diagnosis in experimental and field cases of infectious bovine rhinotracheitis and field cases of bovine viral diarrhea in calves. A portion of the cells was washed twice in phosphate buffered saline and a 25 µL drop was placed on microscope slides. The cells were dried, fixed and stained according to the direct fluorescent antibody technique. Another portion of the same specimen was inoculated onto primary bovine skin cell cultures for virus isolation. In the experimental studies for infectious bovine rhinotracheitis, 29/35 specimens were positive by fluorescent antibody technique and 32/35 by cell culture and in the field cases, 22/119 were positive by fluorescent antibody technique and 19/119 by cell culture. In the field cases of bovine viral diarrhea, 28/69 samples were positive by fluorescent antibody technique and 14/69 by cell culture. When fluorescent antibody technique was performed on inoculated cell cultures a total of 24/69 specimens were positive for bovine viral diarrhea. The sensitivity of fluorescent antibody technique was thus comparable to that of cell culture method for infectious bovine rhinotracheitis and bovine viral diarrhea. ImagesFig. 1.Fig. 2.Fig. 3. PMID:6299484

Modeling locomotor dysfunction following spaceflight with Galvanic vestibular stimulation.

PubMed

Moore, Steven T; MacDougall, Hamish G; Peters, Brian T; Bloomberg, Jacob J; Curthoys, Ian S; Cohen, Helen S

2006-10-01

In this study locomotor and gaze dysfunction commonly observed in astronauts following spaceflight were modeled using two Galvanic vestibular stimulation (GVS) paradigms: (1) pseudorandom, and (2) head-coupled (proportional to the summed vertical linear acceleration and yaw angular velocity obtained from a head-mounted Inertial Measurement Unit). Locomotor and gaze function during GVS were assessed by tests previously used to evaluate post-flight astronaut performance; dynamic visual acuity (DVA) during treadmill locomotion at 80 m/min, and navigation of an obstacle course. During treadmill locomotion with pseudorandom GVS there was a 12% decrease in coherence between head pitch and vertical translation at the step frequency relative to the no GVS condition, which was not significantly different to the 15% decrease in coherence observed in astronauts following shuttle missions. This disruption in head stabilization likely resulted in a decrease in DVA equivalent to the reduction in acuity observed in astronauts 6 days after return from extended missions aboard the International Space Station (ISS). There were significant increases in time-to-completion of the obstacle course during both pseudorandom (21%) and head-coupled (14%) GVS, equivalent to an ISS astronaut 5 days post-landing. An attempt to suppress head movement was evident during both pseudorandom and head-coupled GVS while negotiating the obstacle course, with a 20 and 16%, decrease in head pitch and yaw velocity, respectively. The results of this study demonstrate that pseudorandom GVS generates many of the salient features of post-flight locomotor dysfunction observed in astronauts following short and long duration missions. An ambulatory GVS system may prove a useful adjunct to the current pre-flight astronaut training regimen.

Robert Hare's Theory of Galvanism: A Study of Heat and Electricity in Early Nineteenth-Century American Chemistry.

PubMed

Fisher, Amy

2018-04-09

As a professor of chemistry at the University of Pennsylvania, Robert Hare actively shaped early American science. He participated in a large network of scholars, including Joseph Henry, François Arago, and Jacob Berzelius, and experimented with and wrote extensively about electricity and its associated chemical and thermal phenomena. In the early nineteenth century, prominent chemists such as Berzelius and Humphry Davy proclaimed that a revolution had occurred in chemistry through electrical research. Examining Robert Hare's contributions to this discourse, this paper analyzes how Hare's study of electricity and the caloric theory of heat led him to propose a new theory of galvanism. It also examines the reception of Hare's work in America and Great Britain, highlighting the contributions of early American chemists to the development of electrochemistry.

Single-cell imaging techniques for the real-time detection of IP₃ in live cells.

PubMed

Nelson, Carl P

2013-01-01

Inositol 1,4,5-trisphosphate (IP(3)) is a ubiquitous second messenger, derived from the hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP(2)) by enzymes of the phospholipase C (PLC) family. Binding of IP(3) to its cognate receptor in the endoplasmic reticulum membrane leads to release of Ca(2+) into the cytoplasm, which is involved in the regulation of an array of cellular functions. Traditional techniques for the detection of IP(3) have required the extraction of a large number of cells, with limitations in the time resolution of changes in IP(3) and an inability to obtain detailed information on the dynamics of this second messenger in single cells. Recent progress in this field has led to the development of a number of genetically encoded fluorescent biosensors, which upon recombinant expression are able selectively to detect real-time changes in IP(3) in single live cells. In this chapter, I detail protocols for the expression, visualization (by confocol or fluorescence microscopy), and interpretation of data obtained with such biosensors expressed in mammalian cells.

Microcontact Peeling: A Cell Micropatterning Technique for Circumventing Direct Adsorption of Proteins to Hydrophobic PDMS.

PubMed

Yokoyama, Sho; Matsui, Tsubasa S; Deguchi, Shinji

2017-06-19

Microcontact printing (μCPr) is one of the most popular techniques used for cell micropatterning. In conventional μCPr, a polydimethylsiloxane (PDMS) stamp with microfeatures is used to adsorb extracellular matrix (ECM) proteins onto the featured surface and transfer them onto particular areas of a cell culture substrate. However, some types of functional proteins other than ECM have been reported to denature upon direct adsorption to hydrophobic PDMS. Here we describe a detailed protocol of an alternative technique--microcontact peeling (μCPe)--that allows for cell micropatterning while circumventing the step of adsorbing proteins to bare PDMS. This technique employs microfeatured materials with a relatively high surface energy such as copper, instead of using a microfeatured PDMS stamp, to peel off a cell-adhesive layer present on the surface of substrates. Consequently, cell-nonadhesive substrates are exposed at the specific surface that undergoes the physical contact with the microfeatured material. Thus, although μCPe and μCPr are apparently similar, the former does not comprise a process of transferring biomolecules through hydrophobic PDMS. © 2017 by John Wiley & Sons, Inc. Copyright © 2017 John Wiley & Sons, Inc.

Cell separation technique in dilectrophoretic chip with bulk electrode

NASA Astrophysics Data System (ADS)

Iliescu, Ciprian; Tay, Francis E. H.; Xu, Guolin; Yu, Liming

2006-01-01

This paper presents a new technique for separation of two cell populations in a dielectrophoretic chip with bulk silicon electrode. A characteristic of the dielectrophoretic chip is its "sandwich" structure: glass/silicon/glass that generates a unique definition of the microfluidic channel with conductive walls (silicon) and isolating floor and ceiling (glass). The structure confers the opportunity to use the electrodes not only to generate a gradient of the electric field but also to generate a gradient of velocity of the fluid inside the channel. This interesting combination gives rise to a new solution for dielectrophoretic separation of two cell populations. The separation method consists of four steps. First, the microchannel is field with the cells mixture. Second, the cells are trapped in different locations of the microfluidic channel, the cell population which exhibits positive dielectrophoresis is trapped in the area where the distance between the electrodes is the minimum whilst, the other population that exhibit negative dielectrophoresis is trapped where the distance between electrodes is the maximum. In the next step, increasing the flow in the microchannel will result in an increased hydrodynamic force that sweeps the cells trapped by positive dielectrophoresis out of the chip. In the last step, the electric field is removed and the second population is sweep out and collected at the outlet. The device was tested for separation of dead yeast cells from live yeast cells. The paper presents analytical aspects of the separation method a comparative study between different electrode profiles and experimental results.

From the rat to the beta cell: a fast and effective technique of separation of Langerhans islets and direct purification of pancreatic beta cells.

PubMed

Tamagno, Gianluca; Vigolo, Simonetta; Olivieri, Massimiliano; Martini, Chiara; De Carlo, Eugenio

2014-01-01

Isolated Langerhans islets represent a useful model for the study of the endocrine pancreas. The possibility to purify pancreatic beta cells from a mixed Langerhans islet cell population may lead towards a dedicated focus on beta cell research. We describe an effective and rapid immunomagnetic technique for the direct purification of beta cells from isolated Langerhans islets of rat. After the sacrifice of the rat, the Langerhans islets were separated by ductal injection of the pancreas with collagenase, altered to a mixed Langerhans islet cell population and incubated with conditioned immunomagnetic beads targeted to the beta cell surface. The beads were previously coated with a specific antibody against the surface of the beta cell, namely K14D10. The suspension of mixed Langerhans islet cells and immunomagnetic K14D10-conditioned beads was pelleted by a magnetic particle concentrator to isolate the bead-bound cells, which were finally suspended in a culture medium. The purified cells were immunoreactive for insulin and no glucagon-positive cells were detected at immunocytochemistry. Real Time PCR confirmed the purification of the pancreatic beta cells. This immunomagnetic technique allows a rapid, effective and consistent purification of beta cells from isolated Langerhans islets in a direct manner by conditioning the immunomagnetic beads only. This technique is easy, fast and reproducible. It promises to be a reliable method for providing purified beta cells for in vitro research.

Single cell and single molecule techniques for the analysis of the epigenome

NASA Astrophysics Data System (ADS)

Wallin, Christopher Benjamin

Epigenetic regulation is a critical biological process for the health and development of a cell. Epigenetic regulation is facilitated by covalent modifications to the underlying DNA and chromatin proteins. A fundamental understanding of these epigenetic modifications and their associated interactions at the molecular scale is necessary to explain phenomena including cellular identity, stem cell plasticity, and neoplastic transformation. It is widely known that abnormal epigenetic profiles have been linked to many diseases, most notably cancer. While the field of epigenetics has progressed rapidly with conventional techniques, significant advances remain to be made with respect to combinatoric analysis of epigenetic marks and single cell epigenetics. Therefore, in this dissertation, I will discuss our development of devices and methodologies to address these pertinent issues. First, we designed a preparatory polydimethylsiloxane (PDMS) microdevice for the extraction, purification, and stretching of human chromosomal DNA and chromatin from small cell populations down to a single cell. The valveless device captures cells by size exclusion within the micropillars, entraps the DNA or chromatin in the micropillars after cell lysis, purifies away the cellular debris, and fluorescently labels the DNA and/or chromatin all within a single reaction chamber. With the device, we achieve nearly 100% extraction efficiency of the DNA. The device is also used for in-channel immunostaining of chromatin followed by downstream single molecule chromatin analysis in nanochannels (SCAN). Second, using multi-color, time-correlated single molecule measurements in nanochannels, simultaneous coincidence detection of 2 epigenetic marks is demonstrated. Coincidence detection of 3 epigenetic marks is also established using a pulsed interleaved excitation scheme. With these two promising results, genome-wide quantification of epigenetic marks was pursued. Unfortunately, quantitative SCAN never

Optimized feline vitrectomy technique for therapeutic stem cell delivery to the inner retina

PubMed Central

Jayaram, Hari; Becker, Silke; Eastlake, Karen; Jones, Megan F; Charteris, David G; Limb, G Astrid

2014-01-01

Objective To describe an optimized surgical technique for feline vitrectomy which reduces bleeding and aids posterior gel clearance in order to facilitate stem cell delivery to the inner retina using cellular scaffolds. Procedures Three-port pars plana vitrectomies were performed in six-specific pathogen-free domestic cats using an optimized surgical technique to improve access and minimize severe intraoperative bleeding. Results The surgical procedure was successfully completed in all six animals. Lens sparing vitrectomy resulted in peripheral lens touch in one of three animals but without cataract formation. Transient bleeding from sclerotomies, which was readily controlled, was seen in two of the six animals. No cases of vitreous hemorrhage, severe postoperative inflammation, retinal detachment, or endophthalmitis were observed during postoperative follow-up. Conclusions Three-port pars plana vitrectomy can be performed successfully in the cat in a safe and controlled manner when the appropriate precautions are taken to minimize the risk of developing intraoperative hemorrhage. This technique may facilitate the use of feline models of inner retinal degeneration for the development of stem cell transplantation techniques using cellular scaffolds. PMID:24661435

Galvanic displacement assembly of ultrathin Co3O4 nanosheet arrays on nickel foam for a high-performance supercapacitor

NASA Astrophysics Data System (ADS)

You, Yuxiu; Zheng, Maojun; Ma, Liguo; Yuan, Xiaoliang; Zhang, Bin; Li, Qiang; Wang, Faze; Song, Jingnan; Jiang, Dongkai; Liu, Pengjie; Ma, Li; Shen, Wenzhong

2017-03-01

High-performance supercapacitors are very desirable for many portable electronic devices, electric vehicles and high-power electronic devices. Herein, a facile and binder-free synthesis method, galvanic displacement of the precursor followed by heat treatment, is used to fabricate ultrathin Co3O4 nanosheet arrays on nickel foam substrate. When used as a supercapacitor electrode the prepared Co3O4 on nickel foam exhibits a maximum specific capacitance of 1095 F g-1 at a current density of 1 A g-1 and good cycling stability of 71% retention after 2000 cycling tests. This excellent electrochemical performance can be ascribed to the high specific surface area of each Co3O4 nanosheet that comprises numerous nanoparticles.

Novel measurement techniques (development and analysis of silicon solar cells near 20% effciency)

NASA Technical Reports Server (NTRS)

Wolf, M.; Newhouse, M.

1986-01-01

Work in identifying, developing, and analyzing techniques for measuring bulk recombination rates, and surface recombination velocities and rates in all regions of high-efficiency silicon solar cells is presented. The accuracy of the previously developed DC measurement system was improved by adding blocked interference filters. The system was further automated by writing software that completely samples the unkown solar cell regions with data of numerous recombination velocity and lifetime pairs. The results can be displayed in three dimensions and the best fit can be found numerically using the simplex minimization algorithm. Also described is a theoretical methodology to analyze and compare existing dynamic measurement techniques.

Novel measurement techniques (development and analysis of silicon solar cells near 20% effciency)

NASA Astrophysics Data System (ADS)

Wolf, M.; Newhouse, M.

Work in identifying, developing, and analyzing techniques for measuring bulk recombination rates, and surface recombination velocities and rates in all regions of high-efficiency silicon solar cells is presented. The accuracy of the previously developed DC measurement system was improved by adding blocked interference filters. The system was further automated by writing software that completely samples the unkown solar cell regions with data of numerous recombination velocity and lifetime pairs. The results can be displayed in three dimensions and the best fit can be found numerically using the simplex minimization algorithm. Also described is a theoretical methodology to analyze and compare existing dynamic measurement techniques.

Starvation is more efficient than the washing technique for purification of rat Sertoli cells.

PubMed

Ghasemzadeh-Hasankolaei, Mohammad; Eslaminejad, Mohamadreza Baghaban; Sedighi-Gilani, Mohammadali; Mokarizadeh, Aram

2014-09-01

Sertoli cells (SCs), one of the most important components of seminiferous tubules, are vital for normal spermatogenesis and male fertility. In recent years, numerous in vitro studies have shown the potential and actual activities of SCs. However, pure SCs are necessary for various in vitro studies. In this study, we have evaluated the efficiency of the starvation method for SC purification as compared with the washing method. Seminiferous tubule-derived cells (STDCs) of rats' testes underwent two different techniques for SC purification. In the first group (washing group), the medium was changed every 3-4 d, and cells were washed twice with phosphate-buffered saline that lacked CaC12 and MgSO4 (PBS(-)) before the addition of fresh medium. In the second group (starvation), the medium was changed every 7-8 d. Primary culture (P0), passage 1 (P1), and passage 2 (P2) cells were analyzed for the expression of SC-specific genes, vimentin, Wilm's tumor 1 (WT1), germ cell gene (vasa), Leydig cell marker, 17beta-hydroxysteroid dehydrogenase type 3 (Hsd17b3), and a marker of peritubular myoid cells, alpha smooth muscle actin (αSma), by reverse transcriptase polymerase chain reaction (RT-PCR) and real-time RT-PCR. Gene expression analysis showed that P0 cells expressed all tested genes except Hsd17b3. The starvation method caused significant downregulation of vasa and αSma expression in P0, P1, and P2 cells, whereas vimentin and WT1 were upregulated. In contrast, the washing method was less effective than the starvation method for the removal of germ and pretubular myoid cells (p < 0.001). Totally, the results have revealed that although washing is the only common technique for elimination of contaminant cells in SC cultures, starvation has a stronger effect and is a suitable, affordable technique for SC purification. We propose that starvation is an efficient, inexpensive method that can be used for purification of SCs in animal species.

Laboratory blood analysis in Strigiformes-Part I: hematologic reference intervals and agreement between manual blood cell counting techniques.

PubMed

Ammersbach, Mélanie; Beaufrère, Hugues; Gionet Rollick, Annick; Tully, Thomas

2015-03-01

While hematologic reference intervals (RI) are available for multiple raptorial species of the order Accipitriformes and Falconiformes, there is a lack of valuable hematologic information in Strigiformes that can be used for diagnostic and health monitoring purposes. The objective was to report RI in Strigiformes for hematologic variables and to assess agreement between manual cell counting techniques. A multi-center prospective study was designed to assess hematologic RI and blood cell morphology in owl species. Samples were collected from individuals representing 13 Strigiformes species, including Great Horned Owl, Snowy Owl, Eurasian Eagle Owl, Barred Owl, Great Gray Owl, Ural Owl, Northern Saw-Whet Owls, Northern Hawk Owl, Spectacled Owl, Barn Owl, Eastern Screech Owl, Long-Eared Owl, and Short-Eared Owl. Red blood cell count was determined manually using a hemocytometer. White blood cell count was determined using 3 manual counting techniques: (1) phloxine B technique, (2) Natt and Herrick technique, and (3) estimation from the smear. Differential counts and blood cell morphology were determined on smears. Reference intervals were determined and agreement between methods was calculated. Important species-specific differences were observed in blood cell counts and granulocyte morphology. Differences in WBC count between species did not appear to be predictable based on phylogenetic relationships. Overall, most boreal owl species exhibited a lower WBC count than other species. Important disagreements were found between different manual WBC counting techniques. Disagreements observed between manual counting techniques suggest that technique-specific RI should be used in Strigiformes. © 2015 American Society for Veterinary Clinical Pathology.

Laboratory instrumentation and techniques for characterizing multi-junction solar cells for space applications

NASA Technical Reports Server (NTRS)

Woodyard, James R.

1995-01-01

Multi-junction solar cells are attractive for space applications because they can be designed to convert a larger fraction of AMO into electrical power at a lower cost than single-junction cells. The performance of multi-junction cells is much more sensitive to the spectral irradiance of the illuminating source than single-junction cells. The design of high efficiency multi-junction cells for space applications requires matching the optoelectronic properties of the junctions to AMO spectral irradiance. Unlike single-junction cells, it is not possible to carry out quantum efficiency measurements using only a monochromatic probe beam and determining the cell short-circuit current assuming linearity of the quantum efficiency. Additionally, current-voltage characteristics can not be calculated from measurements under non-AMO light sources using spectral-correction methods. There are reports in the literature on characterizing the performance of multi junction cells by measuring and convoluting the quantum efficiency of each junction with the spectral irradiance; the technique is of limited value for the characterization of cell performance under AMO power-generating conditions. We report the results of research to develop instrumentation and techniques for characterizing multi junction solar cells for space . An integrated system is described which consists of a standard lamp, spectral radiometer, dual-source solar simulator, and personal computer based current-voltage and quantum efficiency equipment. The spectral radiometer is calibrated regularly using the tungsten-halogen standard lamp which has a calibration based on NIST scales. The solar simulator produces the light bias beam for current-voltage and cell quantum efficiency measurements. The calibrated spectral radiometer is used to 'fit' the spectral irradiance of the dual-source solar simulator to WRL AMO data. The quantum efficiency apparatus includes a monochromatic probe beam for measuring the absolute cell

Effect of Process Variables on the Grain Size and Crystallographic Texture of Hot-Dip Galvanized Coatings

NASA Astrophysics Data System (ADS)

Kaboli, Shirin; McDermid, Joseph R.

2014-08-01

A galvanizing simulator was used to determine the effect of galvanizing bath antimony (Sb) content, substrate surface roughness, and cooling rate on the microstructural development of metallic zinc coatings. Substrate surface roughness was varied through the use of relatively rough hot-rolled and relatively smooth bright-rolled steels, cooling rates were varied from 0.1 to 10 K/s, and bulk bath Sb levels were varied from 0 to 0.1 wt pct. In general, it was found that increasing bath Sb content resulted in coatings with a larger grain size and strongly promoted the development of coatings with the close-packed {0002} basal plane parallel to the substrate surface. Increasing substrate surface roughness tended to decrease the coating grain size and promoted a more random coating crystallographic texture, except in the case of the highest Sb content bath (0.1 wt pct Sb), where substrate roughness had no significant effect on grain size except at higher cooling rates (10 K/s). Increased cooling rates tended to decrease the coating grain size and promote the {0002} basal orientation. Calculations showed that increasing the bath Sb content from 0 to 0.1 wt pct Sb increased the dendrite tip growth velocity from 0.06 to 0.11 cm/s by decreasing the solid-liquid interface surface energy from 0.77 to 0.45 J/m2. Increased dendrite tip velocity only partially explains the formation of larger zinc grains at higher Sb levels. It was also found that the classic nucleation theory cannot completely explain the present experimental observations, particularly the effect of increasing the bath Sb, where the classical theory predicts increased nucleation and a finer grain size. In this case, the "poisoning" theory of nucleation sites by segregated Sb may provide a partial explanation. However, any analysis is greatly hampered by the lack of fundamental thermodynamic information such as partition coefficients and surface energies and by a lack of fundamental structural studies. Overall

Cells and Stripes: A novel quantitative photo-manipulation technique

PubMed Central

Mistrik, Martin; Vesela, Eva; Furst, Tomas; Hanzlikova, Hana; Frydrych, Ivo; Gursky, Jan; Majera, Dusana; Bartek, Jiri

2016-01-01

Laser micro-irradiation is a technology widely used in the DNA damage response, checkpoint signaling, chromatin remodeling and related research fields, to assess chromatin modifications and recruitment of diverse DNA damage sensors, mediators and repair proteins to sites of DNA lesions. While this approach has aided numerous discoveries related to cell biology, maintenance of genome integrity, aging and cancer, it has so far been limited by a tedious manual definition of laser-irradiated subcellular regions, with the ensuing restriction to only a small number of cells treated and analyzed in a single experiment. Here, we present an improved and versatile alternative to the micro-irradiation approach: Quantitative analysis of photo-manipulated samples using innovative settings of standard laser-scanning microscopes. Up to 200 cells are simultaneously exposed to a laser beam in a defined pattern of collinear rays. The induced striation pattern is then automatically evaluated by a simple algorithm, which provides a quantitative assessment of various laser-induced phenotypes in live or fixed cells. Overall, this new approach represents a more robust alternative to existing techniques, and provides a versatile tool for a wide range of applications in biomedicine. PMID:26777522

Central adaptation to repeated galvanic vestibular stimulation: implications for pre-flight astronaut training.

PubMed

Dilda, Valentina; Morris, Tiffany R; Yungher, Don A; MacDougall, Hamish G; Moore, Steven T

2014-01-01

Healthy subjects (N = 10) were exposed to 10-min cumulative pseudorandom bilateral bipolar Galvanic vestibular stimulation (GVS) on a weekly basis for 12 weeks (120 min total exposure). During each trial subjects performed computerized dynamic posturography and eye movements were measured using digital video-oculography. Follow up tests were conducted 6 weeks and 6 months after the 12-week adaptation period. Postural performance was significantly impaired during GVS at first exposure, but recovered to baseline over a period of 7-8 weeks (70-80 min GVS exposure). This postural recovery was maintained 6 months after adaptation. In contrast, the roll vestibulo-ocular reflex response to GVS was not attenuated by repeated exposure. This suggests that GVS adaptation did not occur at the vestibular end-organs or involve changes in low-level (brainstem-mediated) vestibulo-ocular or vestibulo-spinal reflexes. Faced with unreliable vestibular input, the cerebellum reweighted sensory input to emphasize veridical extra-vestibular information, such as somatosensation, vision and visceral stretch receptors, to regain postural function. After a period of recovery subjects exhibited dual adaption and the ability to rapidly switch between the perturbed (GVS) and natural vestibular state for up to 6 months.

Galvanic Liquid Applied Coating System For Protection of Embedded Steel Surfaces from Corrosion

NASA Technical Reports Server (NTRS)

Curran, Joseph; Curran, Jerome; Voska, N. (Technical Monitor)

2002-01-01

Corrosion of reinforcing steel in concrete is an insidious problem facing Kennedy Space Center (KSC), other Government Agencies, and the general public. These problems include KSC launch support structures, highway bridge infrastructure, and building structures such as condominium balconies. Due to these problems, the development of a Galvanic Liquid Applied Coating System would be a breakthrough technology having great commercial value for the following industries: Transportation, Infrastructure, Marine Infrastructure, Civil Engineering, and the Construction Industry. This sacrificial coating system consists of a paint matrix that may include metallic components, conducting agents, and moisture attractors. Similar systems have been used in the past with varying degrees of success. These systems have no proven history of effectiveness over the long term. In addition, these types of systems have had limited success overcoming the initial resistance between the concrete/coating interface. The coating developed at KSC incorporates methods proven to overcome the barriers that previous systems could not achieve. Successful development and continued optimization of this breakthrough system would produce great interest in NASA/KSC for corrosion engineering technology and problem solutions. Commercial patents on this technology would enhance KSC's ability to attract industry partners for similar corrosion control applications.

Organic solar cells and physics education

NASA Astrophysics Data System (ADS)

Csernovszky, Zoltán; Horváth, Ákos

2018-07-01

This paper explains the operational principles of a home-made organic solar cell with the representation of an electron-cycle on an energy-level diagram. We present test data for a home-made organic solar cell which operates as a galvanic cell and current source in an electrical circuit. To determine the maximum power of the cell, the optimal current was estimated with a linear approximation. Using different light sources and dyes, the electrical properties of organic solar cells were compared. The solar cells were studied by looking at spectrophotometric data from different sensitizer dyes, generated by a do-it-yourself diffraction grating spectroscope. The sensitizer dyes of solar cells were tested by the diffraction grating spectroscope. The data were analysed on a light-intensity‑wavelength diagram to discover which photons were absorbed and to understand the colours of the fruits containing these dyes. In terms of theoretical applications, the paper underlines the analogous nature of organic solar cells, a conventional single p‑n junction solar cell and the light-dependent reactions of photosynthesis, using energy-level diagrams of electron-cycles. To conclude, a classification of photon‑electron interactions in molecular systems and crystal lattices is offered, to show the importance of organic solar cells.

Confocal micro-Raman spectroscopy of single biological cells using optical trapping and shifted excitation difference techniques

NASA Astrophysics Data System (ADS)

Xie, Changan; Li, Yong-qing

2003-03-01

We report on the study of single biological cells with a confocal micro-Raman spectroscopy system that uses optical trapping and shifted excitation Raman difference technique. A tunable diode laser was used to capture a living cell in solution, confine it in the confocal excitation volume, and then excite the Raman scattering. The optical trapping allows us to lift the cell well off the cover plate so that the fluorescence interference from the plate can be effectively reduced. In order to further remove the interference of the fluorescence and stray light from the trapped cell, we employed a shifted excitation Raman difference technique with slightly tuned laser frequencies. With this system, high-quality Raman spectra were obtained from single optically trapped biological cells including E. coli bacteria, yeast cells, and red blood cells. A significant difference between control and heat-treated E. coli B cells was observed due to the denaturation of biomolecules.

Selective Oxidation and Reactive Wetting During Hot-Dip Galvanizing of a 1.0 pct Al-0.5 pct Si TRIP-Assisted Steel

NASA Astrophysics Data System (ADS)

Bellhouse, E. M.; McDermid, J. R.

2012-07-01

Selective oxidation and reactive wetting during continuous galvanizing were studied for a low-alloy transformation induced plasticity (TRIP)-assisted steel with 0.2 pct C, 1.5 pct Mn, 1.0 pct Al and 0.5 pct Si. Three process atmospheres were tested during annealing prior to galvanizing: 220 K (-53 °C) dew point (dp) N2-20 pct H2, 243 K (-30 °C) dp N2-5 pct H2 and 278 K (+5 °C) dp N2-5 pct H2. The process atmosphere oxygen partial pressure affected the oxide chemistry, morphology and thickness. For the 220 K (-53 °C) dp and 243 K (-30 °C) dp process atmospheres, film and nodule-type manganese, silicon and aluminum containing oxides were observed at the surface. For the 278 K (+5 °C) dp atmosphere, MnO was observed at the grain boundaries and as thicker localized surface films. Oxide morphology, thickness and chemistry affected reactive wetting, with complete wetting being observed for the 220 K (-53 °C) dp and 243 K (-30 °C) dp process atmospheres and incomplete reactive wetting being observed for the 278 K (+5 °C) dp atmosphere. Complete reactive wetting for the 220 K (-53 °C) dp and 243 K (-30 °C) dp process atmospheres was attributed to a combination of zinc bridging of oxides, aluminothermic reduction of surface oxides and wetting of the oxides. Incomplete wetting for the 278 K (+5 °C) dp atmosphere was attributed to localized thick MnO films.

Selective hydrodechlorination of 1,2-dichloroethane catalyzed by trace Pd decorated Ag/Al2O3 catalysts prepared by galvanic replacement

NASA Astrophysics Data System (ADS)

Sun, Jingya; Han, Yuxiang; Fu, Heyun; Wan, Haiqin; Xu, Zhaoyi; Zheng, Shourong

2018-01-01

Ag catalysts decorated by trace Pd supported on γ-Al2O3 with different structure and chemical properties were prepared using a combined impregnation and galvanic replacement method. For comparison, monometallic Ag/γ-Al2O3 and Pd/γ-Al2O3 catalysts were prepared using the impregnation method. Gas-phase catalytic hydrodechlorination of 1,2-dichloroethane to ethylene was investigated on those catalysts. The structures and chemical compositions of bimetallic Pd-Ag particles in the catalysts were controlled by adjusting Pd replacement amount. The as-prepared catalysts were characterized by X-ray diffraction, transmission electron microscopy, UV-vis diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, and in-situ FTIR spectroscopy of CO adsorption. The results demonstrated that contiguous Pd sites dominated in the monometallic Pd/γ-Al2O3 catalyst, while Pd atoms were separately decorated on the surface of Ag particles in the bimetallic Pd-Ag/γ-Al2O3 catalysts when Pd replacement amount was below 0.30 wt.%. At Pd replacement amount of 0.30 wt.%, Pd ensembles with contiguous Pd sites developed in the bimetallic catalyst. Thus, monometallic Pd/γ-Al2O3 catalyst displayed negligible ethylene selectivity toward the catalytic hydrodechlorination of 1,2-dichloroethane, while bimetallic Pd-Ag/γ-Al2O3 catalyst with a Pd replacement amount of 0.13 wt.% exhibited 94.6% of ethylene selectivity. Furthermore, selectivity to incompletely dechlorinated byproduct chloroethylene decreased with Pd replacement amount, due to the enhanced decoration effect of Pd on large Ag ensembles. Findings in this work provide a promising bimetallic catalyst prepared by galvanic replacement for the selective catalytic hydrodechlorination of 1,2-dichloroethane.

Optimized feline vitrectomy technique for therapeutic stem cell delivery to the inner retina.

PubMed

Jayaram, Hari; Becker, Silke; Eastlake, Karen; Jones, Megan F; Charteris, David G; Limb, G Astrid

2014-07-01

To describe an optimized surgical technique for feline vitrectomy which reduces bleeding and aids posterior gel clearance in order to facilitate stem cell delivery to the inner retina using cellular scaffolds. Three-port pars plana vitrectomies were performed in six-specific pathogen-free domestic cats using an optimized surgical technique to improve access and minimize severe intraoperative bleeding. The surgical procedure was successfully completed in all six animals. Lens sparing vitrectomy resulted in peripheral lens touch in one of three animals but without cataract formation. Transient bleeding from sclerotomies, which was readily controlled, was seen in two of the six animals. No cases of vitreous hemorrhage, severe postoperative inflammation, retinal detachment, or endophthalmitis were observed during postoperative follow-up. Three-port pars plana vitrectomy can be performed successfully in the cat in a safe and controlled manner when the appropriate precautions are taken to minimize the risk of developing intraoperative hemorrhage. This technique may facilitate the use of feline models of inner retinal degeneration for the development of stem cell transplantation techniques using cellular scaffolds. © 2014 The Authors Veterinary Ophthalmology published by Wiley Periodicals, Inc. on behalf of American College of Veterinary Ophthalmologists.

High-quality cell block preparation from scraping of conventional cytology slide: a technical report on a modified cytoscrape cell block technique.

PubMed

Choi, Y I; Jakhongir, M; Choi, S J; Kim, L; Park, I S; Han, J Y; Kim, J M; Chu, Y C

2016-12-01

Immunocytochemistry (ICC) on formalin-fixed paraffin embedded cell blocks is an ancillary tool commonly recruited for differential diagnoses of fine needle aspiration cytology (FNAC) samples. However, the quality of conventional cell blocks in terms of adequate cellularity and evenness of distribution of cytologic material is not always satisfactory for ICC. We introduce a modified agarose-based cytoscrape cell block (CCB) technique that can be effectively used for the preparation of cell blocks from scrapings of conventional FNAC slides. A decoverslipped FNAC slide was mounted with a small amount of water. The cytological material was scraped off the slide into a tissue mold by scraping with a cell scraper. The cytoscrape material was pelleted by centrifugation and pre-embedded in ultra-low gelling temperature agarose and then re-embedded in conventional agarose. The final agarose gel disk was processed and embedded in paraffin. The quality of the ICC on the CCB sections was identical to that of the immunohistochemical stains on histological sections. By scrapping and harvesting the entirety of the cytological material off the cytology slide into a compact agarose cell button, we could avoid the risk of losing diagnostic material during the CCB preparation. This modified CCB technique enables concentration and focusing of minute material while maintaining the entire amount of the cytoscrape material on the viewing spot of the CCB sections. We believe this technique can be effectively used to improve the level of confidence in diagnosis of FNAC especially when the FNAC slides are the only sample available.

APPARATUS FOR CONVERTING HEAT INTO ELECTRICITY

DOEpatents

Crouthamel, C.E.; Foster, M.S.

1964-01-28

This patent shows an apparatus for converting heat to electricity. It includes a galvanic cell having an anodic metal anode, a fused salt electrolyte, and a hydrogen cathode having a diffusible metal barrier of silver-- palladium alloy covered with sputtered iron on the side next to the fused electrolyte. Also shown is a regenerator for regenerating metal hydride produced by the galvanic cell into hydrogen gas and anodic metal, both of which are recycled. (AEC)

Fluorescence exclusion: A simple versatile technique to calculate cell volumes and local heights (Conference Presentation)

NASA Astrophysics Data System (ADS)

Thouvenin, Olivier; Fink, Mathias; Boccara, A. Claude

2017-02-01

Understanding volume regulation during mitosis is technically challenging. Indeed, a very sensitive non invasive imaging over time scales ranging from seconds to hours and over large fields is required. Therefore, Quantitative Phase Imaging (QPI) would be a perfect tool for such a project. However, because of asymmetric protein segregation during mitosis, an efficient separation of the refractive index and the height in the phase signal is required. Even though many strategies to make such a separation have been developed, they usually are difficult to implement, have poor sensitivity, or cannot be performed in living cells, or in a single shot. In this paper, we will discuss the use of a new technique called fluorescence exclusion to perform volume measurements. By coupling such technique with a simultaneous phase measurement, we were also able to recover the refractive index inside the cells. Fluorescence exclusion is a versatile and powerful technique that allows the volume measurement of many types of cells. A fluorescent dye, which cannot penetrate inside the cells, is mixed with the external medium in a confined environment. Therefore, the fluorescent signal depends on the inverse of the object's height. We could demonstrate both experimentally and theoretically that fluorescence exclusion can accurately measure cell volumes, even for cells much higher than the depth of focus of the objective. A local accurate height and RI measurement can also be obtained for smaller cells. We will also discuss the way to optimize the confinement of the observation chamber, either mechanically or optically.

Generation of Homogenous Three-Dimensional Pancreatic Cancer Cell Spheroids Using an Improved Hanging Drop Technique

PubMed Central

Ware, Matthew J.; Colbert, Kevin; Keshishian, Vazrik; Ho, Jason; Corr, Stuart J.; Curley, Steven A.

2016-01-01

In vitro characterization of tumor cell biology or of potential anticancer drugs is usually performed using tumor cell lines cultured as a monolayer. However, it has been previously shown that three-dimensional (3D) organization of the tumor cells is important to provide insights on tumor biology and transport of therapeutics. Several methods to create 3D tumors in vitro have been proposed, with hanging drop technique being the most simple and, thus, most frequently used. However, in many cell lines this method has failed to form the desired 3D tumor structures. The aim of this study was to design and test an easy-to-use and highly reproducible modification of the hanging drop method for tumor sphere formation by adding methylcellulose polymer. Most pancreatic cancer cells do not form cohesive and manageable spheres when the original hanging drop method is used, thus we investigated these cell lines for our modified hanging drop method. The spheroids produced by this improved technique were analyzed by histology, light microscopy, immunohistochemistry, and scanning electron microscopy. Results show that using the proposed simple method; we were able to produce uniform spheroids for all five of the tested human pancreatic cancer cell lines; Panc-1, BxPC-3, Capan-1, MiaPaCa-2, and AsPC-1. We believe that this method can be used as a reliable and reproducible technique to make 3D cancer spheroids for use in tumor biology research and evaluation of therapeutic responses, and for the development of bio-artificial tissues. PMID:26830354

Generation of Homogenous Three-Dimensional Pancreatic Cancer Cell Spheroids Using an Improved Hanging Drop Technique.

PubMed

Ware, Matthew J; Colbert, Kevin; Keshishian, Vazrik; Ho, Jason; Corr, Stuart J; Curley, Steven A; Godin, Biana

2016-04-01

In vitro characterization of tumor cell biology or of potential anticancer drugs is usually performed using tumor cell lines cultured as a monolayer. However, it has been previously shown that three-dimensional (3D) organization of the tumor cells is important to provide insights on tumor biology and transport of therapeutics. Several methods to create 3D tumors in vitro have been proposed, with hanging drop technique being the most simple and, thus, most frequently used. However, in many cell lines this method has failed to form the desired 3D tumor structures. The aim of this study was to design and test an easy-to-use and highly reproducible modification of the hanging drop method for tumor sphere formation by adding methylcellulose polymer. Most pancreatic cancer cells do not form cohesive and manageable spheres when the original hanging drop method is used, thus we investigated these cell lines for our modified hanging drop method. The spheroids produced by this improved technique were analyzed by histology, light microscopy, immunohistochemistry, and scanning electron microscopy. Results show that using the proposed simple method; we were able to produce uniform spheroids for all five of the tested human pancreatic cancer cell lines; Panc-1, BxPC-3, Capan-1, MiaPaCa-2, and AsPC-1. We believe that this method can be used as a reliable and reproducible technique to make 3D cancer spheroids for use in tumor biology research and evaluation of therapeutic responses, and for the development of bio-artificial tissues.

Giga-ohm seals on intracellular membranes: a technique for studying intracellular ion channels in intact cells.

PubMed

Jonas, E A; Knox, R J; Kaczmarek, L K

1997-07-01

A method is outlined for obtaining giga-ohm seals on intracellular membranes in intact cells. The technique employs a variant of the patch-clamp technique: a concentric electrode arrangement protects an inner patch pipette during penetration of the plasma membrane, after which a seal can be formed on an internal organelle membrane. Using this technique, successful recordings can be obtained with the same frequency as with conventional patch clamping. To localize the position of the pipette within cells, lipophilic fluorescent dyes are included in the pipette solution. These dyes stain the membrane of internal organelles during seal formation and can then be visualized by video-enhanced or confocal imaging. The method can detect channels activated by inositol trisphosphate, as well as other types of intracellular membrane ion channel activity, and should facilitate studies of internal membranes in intact neurons and other cell types.

One-Step Cartilage Repair Technique as a Next Generation of Cell Therapy for Cartilage Defects: Biological Characteristics, Preclinical Application, Surgical Techniques, and Clinical Developments.

PubMed

Zhang, Chi; Cai, You-Zhi; Lin, Xiang-Jin

2016-07-01

To provide a comprehensive overview of the basic science rationale, surgical technique, and clinical outcomes of 1-step cartilage repair technique used as a treatment strategy for cartilage defects. A systematic review was performed in the main medical databases to evaluate the several studies concerning 1-step procedures for cartilage repair. The characteristics of cell-seed scaffolds, behavior of cells seeded into scaffolds, and surgical techniques were also discussed. Clinical outcomes and quality of repaired tissue were assessed using several standardized outcome assessment tools, magnetic resonance imaging scans, and biopsy histology. One-step cartilage repair could be divided into 2 types: chondrocyte-matrix complex (CMC) and autologous matrix-induced chondrogenesis (AMIC), both of which allow a simplified surgical approach. Studies with Level IV evidence have shown that 1-step cartilage repair techniques could significantly relieve symptoms and improve functional assessment (P < .05, compared with preoperative evaluation) at short-term follow-up. Furthermore, magnetic resonance imaging showed that 76% cases in all included case series showed at least 75% defect coverage in each lesion, and 3 studies clearly showed hyaline-like cartilage tissue in biopsy tissues by second-look arthroscopy. The 1-step cartilage repair technique, with its potential for effective, homogeneous distribution of chondrocytes and multipotent stem cells on the surface of the cartilage defect, is able to regenerate hyaline-like cartilage tissue, and it could be applied to cartilage repair by arthroscopy. Level IV, systematic review of Level II and IV studies. Copyright © 2016 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

Interphase cytogenetics of B-cell chronic lymphocytic leukemia by FISH-technique

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peddanna, N.; Gogineni, S.K.; Rosenthal, C.J.

Chronic lymphocytic leukemia [CLL] accounts for about 30% of all lymphoproliferative disorders. In over 95% of these cases, the leukemia is caused by B-cells, rarely T-cells. Fifty percent of B-CLL have chromosomal aberrations and of such cases, one-third have trisomy 12. Malignant B-cells have a very low mitotic index and those metaphases that can be analyzed usually represent the normal T-cell population. Retrospectively, we decided to identify the additional chromosome 12 (trisomy 12) directly at interphase by the FISH-technique using centrometric 12 specific alphoid probe (Oncor, Gaithersburg, MD). Preparations were made from 9 patients with B-CLL. All cultures except onemore » failed to produce metaphases for conventional karyotyping. Eighty percent of the cells have two dots (normal cells) over the interphase nuclei while the remaining 20% have three dots (trisomy 12). The clinical implication of trisomy 12 in the pathogenesis of CLL including age, staging and duration of disease, differentials and immunological markers are correlated with interphase cytogenetic data. The loss and/or gain of specific chromosomes in human neoplasia is common and rapid evaluation of such cases should be considered as a routine approach.« less

Review of the Potential of the Ni/Cu Plating Technique for Crystalline Silicon Solar Cells

PubMed Central

Rehman, Atteq ur; Lee, Soo Hong

2014-01-01

Developing a better method for the metallization of silicon solar cells is integral part of realizing superior efficiency. Currently, contact realization using screen printing is the leading technology in the silicon based photovoltaic industry, as it is simple and fast. However, the problem with metallization of this kind is that it has a lower aspect ratio and higher contact resistance, which limits solar cell efficiency. The mounting cost of silver pastes and decreasing silicon wafer thicknesses encourages silicon solar cell manufacturers to develop fresh metallization techniques involving a lower quantity of silver usage and not relying pressing process of screen printing. In recent times nickel/copper (Ni/Cu) based metal plating has emerged as a metallization method that may solve these issues. This paper offers a detailed review and understanding of a Ni/Cu based plating technique for silicon solar cells. The formation of a Ni seed layer by adopting various deposition techniques and a Cu conducting layer using a light induced plating (LIP) process are appraised. Unlike screen-printed metallization, a step involving patterning is crucial for opening the masking layer. Consequently, experimental procedures involving patterning methods are also explicated. Lastly, the issues of adhesion, back ground plating, process complexity and reliability for industrial applications are also addressed. PMID:28788516

Review of the Potential of the Ni/Cu Plating Technique for Crystalline Silicon Solar Cells.

PubMed

Rehman, Atteq Ur; Lee, Soo Hong

2014-02-18

Developing a better method for the metallization of silicon solar cells is integral part of realizing superior efficiency. Currently, contact realization using screen printing is the leading technology in the silicon based photovoltaic industry, as it is simple and fast. However, the problem with metallization of this kind is that it has a lower aspect ratio and higher contact resistance, which limits solar cell efficiency. The mounting cost of silver pastes and decreasing silicon wafer thicknesses encourages silicon solar cell manufacturers to develop fresh metallization techniques involving a lower quantity of silver usage and not relying pressing process of screen printing. In recent times nickel/copper (Ni/Cu) based metal plating has emerged as a metallization method that may solve these issues. This paper offers a detailed review and understanding of a Ni/Cu based plating technique for silicon solar cells. The formation of a Ni seed layer by adopting various deposition techniques and a Cu conducting layer using a light induced plating (LIP) process are appraised. Unlike screen-printed metallization, a step involving patterning is crucial for opening the masking layer. Consequently, experimental procedures involving patterning methods are also explicated. Lastly, the issues of adhesion, back ground plating, process complexity and reliability for industrial applications are also addressed.

Large-Grain Tin-Rich Perovskite Films for Efficient Solar Cells via Metal Alloying Technique.

PubMed

Tavakoli, Mohammad Mahdi; Zakeeruddin, Shaik Mohammed; Grätzel, Michael; Fan, Zhiyong

2018-03-01

Fast research progress on lead halide perovskite solar cells has been achieved in the past a few years. However, the presence of lead (Pb) in perovskite composition as a toxic element still remains a major issue for large-scale deployment. In this work, a novel and facile technique is presented to fabricate tin (Sn)-rich perovskite film using metal precursors and an alloying technique. Herein, the perovskite films are formed as a result of the reaction between Sn/Pb binary alloy metal precursors and methylammonium iodide (MAI) vapor in a chemical vapor deposition process carried out at 185 °C. It is found that in this approach the Pb/Sn precursors are first converted to (Pb/Sn)I 2 and further reaction with MAI vapor leads to the formation of perovskite films. By using Pb-Sn eutectic alloy, perovskite films with large grain sizes up to 5 µm can be grown directly from liquid phase metal. Consequently, using an alloying technique and this unique growth mechanism, a less-toxic and efficient perovskite solar cell with a power conversion efficiency (PCE) of 14.04% is demonstrated, while pure Sn and Pb perovskite solar cells prepared in this manner yield PCEs of 4.62% and 14.21%, respectively. It is found that this alloying technique can open up a new direction to further explore different alloy systems (binary or ternary alloys) with even lower melting point. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Preparation of micro/nano-structure superhydrophobic film on aluminum plates using galvanic corrosion method.

PubMed

Wu, Ruomei; Chao, Guang Hua; Jiang, Haiyun; Pan, Anqiang; Chen, Hong; Yuan, Zhiqing; Liu, Qilong

2013-10-01

A simple and novel approach has been developed to obtain a microporous film with compound nanoparticles on the surface of aluminum alloy substrate using the galvanic corrosion method. The wettability of the surface changes from hydrophilicity to superhydrophobicity after chemical modification with stearic acid (SA). The water contact angle (WCA) and sliding angle (WSA) of superhydrophobic aluminum alloy surface (SAAS) are 154 degrees and 9 degrees, respectively. The roughness of the aluminum substrate increases after the oxidation reaction. The porous aluminum matrix surface is covered with irregularly shaped holes with a mean radius of about 15 microm, similar to the surface papillae of natural Lotus leaf, with villus-like nanoparticles array on pore surfaces. The superhydrophobic property is attributed to this special surface morphology and low surface energy SA. X-ray powder diffraction (XRD) pattern and Energy Dispersive X-Ray Spectroscopy (EDS) spectrum indicate that Al2O3, Al(OH)3 and AIO(OH) has been formed on the surface of aluminum substrate after the oxidation reaction. The Raman spectra indicate that C-H bond from SA and the Al-O are formed on the SAAS. The as-formed SAAS has good stability.

Comparison of Postural Responses to Galvanic Vestibular Stimulation between Pilots and the General Populace

PubMed Central

Yang, Yang; Pu, Fang; Lv, Xiaoning; Li, Shuyu; Li, Jing; Li, Deyu; Li, Minggao

2015-01-01

Galvanic vestibular stimulation (GVS) can be used to study the body's response to vestibular stimuli. This study aimed to investigate whether postural responses to GVS were different between pilots and the general populace. Bilateral bipolar GVS was applied with a constant-current profile to 12 pilots and 12 control subjects via two electrodes placed over the mastoid processes. Both GVS threshold and the center of pressure's trajectory (COP's trajectory) were measured. Position variability of COP during spontaneous body sway and peak displacement of COP during GVS-induced body sway were calculated in the medial-lateral direction. Spontaneous body sway was slight for all subjects, and there was no significant difference in the value of COP position variability between the pilots and controls. Both the GVS threshold and magnitude of GVS-induced body deviation were similar for different GVS polarities. GVS thresholds were similar between the two groups, but the magnitude of GVS-induced body deviation in the controls was significantly larger than that in the pilots. The pilots showed less GVS-induced body deviation, meaning that pilots may have a stronger ability to suppress vestibular illusions. PMID:25632395

Impedance analysis of cultured cells: a mean-field electrical response model for electric cell-substrate impedance sensing technique.

PubMed

Urdapilleta, E; Bellotti, M; Bonetto, F J

2006-10-01

In this paper we present a model to describe the electrical properties of a confluent cell monolayer cultured on gold microelectrodes to be used with electric cell-substrate impedance sensing technique. This model was developed from microscopic considerations (distributed effects), and by assuming that the monolayer is an element with mean electrical characteristics (specific lumped parameters). No assumptions were made about cell morphology. The model has only three adjustable parameters. This model and other models currently used for data analysis are compared with data we obtained from electrical measurements of confluent monolayers of Madin-Darby Canine Kidney cells. One important parameter is the cell-substrate height and we found that estimates of this magnitude strongly differ depending on the model used for the analysis. We analyze the origin of the discrepancies, concluding that the estimates from the different models can be considered as limits for the true value of the cell-substrate height.

Rapid Fabricating Technique for Multi-Layered Human Hepatic Cell Sheets by Forceful Contraction of the Fibroblast Monolayer

PubMed Central

Sakai, Yusuke; Koike, Makiko; Hasegawa, Hideko; Yamanouchi, Kosho; Soyama, Akihiko; Takatsuki, Mitsuhisa; Kuroki, Tamotsu; Ohashi, Kazuo; Okano, Teruo; Eguchi, Susumu

2013-01-01

Cell sheet engineering is attracting attention from investigators in various fields, from basic research scientists to clinicians focused on regenerative medicine. However, hepatocytes have a limited proliferation potential in vitro, and it generally takes a several days to form a sheet morphology and multi-layered sheets. We herein report our rapid and efficient technique for generating multi-layered human hepatic cell (HepaRG® cell) sheets using pre-cultured fibroblast monolayers derived from human skin (TIG-118 cells) as a feeder layer on a temperature-responsive culture dish. Multi-layered TIG-118/HepaRG cell sheets with a thick morphology were harvested on day 4 of culturing HepaRG cells by forceful contraction of the TIG-118 cells, and the resulting sheet could be easily handled. In addition, the human albumin and alpha 1-antitrypsin synthesis activities of TIG-118/HepaRG cells were approximately 1.2 and 1.3 times higher than those of HepaRG cells, respectively. Therefore, this technique is considered to be a promising modality for rapidly fabricating multi-layered human hepatocyte sheets from cells with limited proliferation potential, and the engineered cell sheet could be used for cell transplantation with highly specific functions. PMID:23923035

Rapid fabricating technique for multi-layered human hepatic cell sheets by forceful contraction of the fibroblast monolayer.

PubMed

Sakai, Yusuke; Koike, Makiko; Hasegawa, Hideko; Yamanouchi, Kosho; Soyama, Akihiko; Takatsuki, Mitsuhisa; Kuroki, Tamotsu; Ohashi, Kazuo; Okano, Teruo; Eguchi, Susumu

2013-01-01

Cell sheet engineering is attracting attention from investigators in various fields, from basic research scientists to clinicians focused on regenerative medicine. However, hepatocytes have a limited proliferation potential in vitro, and it generally takes a several days to form a sheet morphology and multi-layered sheets. We herein report our rapid and efficient technique for generating multi-layered human hepatic cell (HepaRG® cell) sheets using pre-cultured fibroblast monolayers derived from human skin (TIG-118 cells) as a feeder layer on a temperature-responsive culture dish. Multi-layered TIG-118/HepaRG cell sheets with a thick morphology were harvested on day 4 of culturing HepaRG cells by forceful contraction of the TIG-118 cells, and the resulting sheet could be easily handled. In addition, the human albumin and alpha 1-antitrypsin synthesis activities of TIG-118/HepaRG cells were approximately 1.2 and 1.3 times higher than those of HepaRG cells, respectively. Therefore, this technique is considered to be a promising modality for rapidly fabricating multi-layered human hepatocyte sheets from cells with limited proliferation potential, and the engineered cell sheet could be used for cell transplantation with highly specific functions.

Advanced particle-in-cell simulation techniques for modeling the Lockheed Martin Compact Fusion Reactor

NASA Astrophysics Data System (ADS)

Welch, Dale; Font, Gabriel; Mitchell, Robert; Rose, David

2017-10-01

We report on particle-in-cell developments of the study of the Compact Fusion Reactor. Millisecond, two and three-dimensional simulations (cubic meter volume) of confinement and neutral beam heating of the magnetic confinement device requires accurate representation of the complex orbits, near perfect energy conservation, and significant computational power. In order to determine initial plasma fill and neutral beam heating, these simulations include ionization, elastic and charge exchange hydrogen reactions. To this end, we are pursuing fast electromagnetic kinetic modeling algorithms including a two implicit techniques and a hybrid quasi-neutral algorithm with kinetic ions. The kinetic modeling includes use of the Poisson-corrected direct implicit, magnetic implicit, as well as second-order cloud-in-cell techniques. The hybrid algorithm, ignoring electron inertial effects, is two orders of magnitude faster than kinetic but not as accurate with respect to confinement. The advantages and disadvantages of these techniques will be presented. Funded by Lockheed Martin.

Oculo-vestibular recoupling using galvanic vestibular stimulation to mitigate simulator sickness.

PubMed

Cevette, Michael J; Stepanek, Jan; Cocco, Daniela; Galea, Anna M; Pradhan, Gaurav N; Wagner, Linsey S; Oakley, Sarah R; Smith, Benn E; Zapala, David A; Brookler, Kenneth H

2012-06-01

Despite improvement in the computational capabilities of visual displays in flight simulators, intersensory visual-vestibular conflict remains the leading cause of simulator sickness (SS). By using galvanic vestibular stimulation (GVS), the vestibular system can be synchronized with a moving visual field in order to lessen the mismatch of sensory inputs thought to result in SS. A multisite electrode array was used to deliver combinations of GVS in 21 normal subjects. Optimal electrode combinations were identified and used to establish GVS dose-response predictions for the perception of roll, pitch, and yaw. Based on these data, an algorithm was then implemented in flight simulator hardware in order to synchronize visual and GVS-induced vestibular sensations (oculo-vestibular-recoupled or OVR simulation). Subjects were then randomly exposed to flight simulation either with or without OVR simulation. A self-report SS checklist was administered to all subjects after each session. An overall SS score was calculated for each category of symptoms for both groups. The analysis of GVS stimulation data yielded six unique combinations of electrode positions inducing motion perceptions in the three rotational axes. This provided the algorithm used for OVR simulation. The overall SS scores for gastrointestinal, central, and peripheral categories were 17%, 22.4%, and 20% for the Control group and 6.3%, 20%, and 8% for the OVR group, respectively. When virtual head signals produced by GVS are synchronized to the speed and direction of a moving visual field, manifestations of induced SS in a cockpit flight simulator are significantly reduced.

In Situ Monitoring of Pb2+ Leaching from the Galvanic Joint Surface in a Prepared Chlorinated Drinking Water.

PubMed

Ma, Xiangmeng; Armas, Stephanie M; Soliman, Mikhael; Lytle, Darren A; Chumbimuni-Torres, Karin; Tetard, Laurene; Lee, Woo Hyoung

2018-02-20

A novel method using a micro-ion-selective electrode (micro-ISE) technique was developed for in situ lead monitoring at the water-metal interface of a brass-leaded solder galvanic joint in a prepared chlorinated drinking water environment. The developed lead micro-ISE (100 μm tip diameter) showed excellent performance toward soluble lead (Pb 2+ ) with sensitivity of 22.2 ± 0.5 mV decade -1 and limit of detection (LOD) of 1.22 × 10 -6 M (0.25 mg L -1 ). The response time was less than 10 s with a working pH range of 2.0-7.0. Using the lead micro-ISE, lead concentration microprofiles were measured from the bulk to the metal surface (within 50 μm) over time. Combined with two-dimensional (2D) pH mapping, this work clearly demonstrated that Pb 2+ ions build-up across the lead anode surface was substantial, nonuniform, and dependent on local surface pH. A large pH gradient (ΔpH = 6.0) developed across the brass and leaded-tin solder joint coupon. Local pH decreases were observed above the leaded solder to a pH as low as 4.0, indicating it was anodic relative to the brass. The low pH above the leaded solder supported elevated lead levels where even small local pH differences of 0.6 units (ΔpH = 0.6) resulted in about four times higher surface lead concentrations (42.9 vs 11.6 mg L -1 ) and 5 times higher fluxes (18.5 × 10 -6 vs 3.5 × 10 -6 mg cm -2 s -1 ). Continuous surface lead leaching monitoring was also conducted for 16 h.

The strong reactions of Lewis-base noble-metals with vanadium and other acidic transition metals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ebbinghaus, B.B.

1991-05-01

The noble metals often thought of as unreactive solids,react strongly with nearly 40% of the elements in the periodictable: group IIIB-VB transition metals, lanthanides, theactinides, and group IIIA-IVA non-transition metals. These strong reactions arise from increased bonding/electron transfer fromnonbonding electrons d electron pairs on the noble metal tovacant orbitals on V, etc. This effect is a generalized Lewis acid-base interaction. The partial Gibbs energy of V in the noblemetals has been measured as a function of concentration at a temperature near 1000C. Thermodynamics of the intermetallics are determined by ternary oxide equilibria, ternary carbide equilibria, and the high-temperature galvanic cellmore » technique. These experimental methods use equilibrated solid composite mixtures in which grains of V oxides or of V carbides are interspersed with grains of V-NM(noble-metal) alloys. In equilibrium the activity of V in the oxide or the carbide equals the activity in the alloy. Consequently, the thermodynamics available in the literature for the V oxides and V carbides are reviewed. Test runs on the galvanic cell were attempted. The V oxide electrode reacts with CaF[sub 2], ThO[sub 2], YDT(0.85ThO[sub 2]-0.15YO[sub 1.5]), and LDT(0.85ThO[sub 2]- 0.15LaO[sub 1.5]) to interfere with the measured data observed toward the beginning of a galvanic cell experiment are the most accurate. The interaction of vanadium at infinite dilution in the noble-metals was determined.« less

The strong reactions of Lewis-base noble-metals with vanadium and other acidic transition metals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ebbinghaus, Bartley B.

1991-05-01

The noble metals often thought of as unreactive solids,react strongly with nearly 40% of the elements in the periodictable: group IIIB-VB transition metals, lanthanides, theactinides, and group IIIA-IVA non-transition metals. These strong reactions arise from increased bonding/electron transfer fromnonbonding electrons d electron pairs on the noble metal tovacant orbitals on V, etc. This effect is a generalized Lewis acid-base interaction. The partial Gibbs energy of V in the noblemetals has been measured as a function of concentration at a temperature near 1000C. Thermodynamics of the intermetallics are determined by ternary oxide equilibria, ternary carbide equilibria, and the high-temperature galvanic cellmore » technique. These experimental methods use equilibrated solid composite mixtures in which grains of V oxides or of V carbides are interspersed with grains of V-NM(noble-metal) alloys. In equilibrium the activity of V in the oxide or the carbide equals the activity in the alloy. Consequently, the thermodynamics available in the literature for the V oxides and V carbides are reviewed. Test runs on the galvanic cell were attempted. The V oxide electrode reacts with CaF 2, ThO 2, YDT(0.85ThO 2-0.15YO 1.5), and LDT(0.85ThO 2- 0.15LaO 1.5) to interfere with the measured data observed toward the beginning of a galvanic cell experiment are the most accurate. The interaction of vanadium at infinite dilution in the noble-metals was determined.« less

Identification of techniques to meet pH standard during in-stream construction.

DOT National Transportation Integrated Search

2014-03-01

Many of Marylands tributaries traverse highway infrastructure via culverts that are managed : and maintained by SHA. These culverts are often made of galvanized steel and over time are : subjected to scour. Concrete grout is often used as a repair...

Patch-clamp, ion-sensing, and glutamate-sensing techniques to study glutamate transport in isolated retinal glial cells.

PubMed

Billups, B; Szatkowski, M; Rossi, D; Attwell, D

1998-01-01

We have described how a combination of electrical, ion-sensing, and glutamate-sensing techniques has advanced our understanding of glutamate uptake into isolated salamander retinal glial cells. The next steps in understanding glutamate transport will inevitably depend strongly on molecular biological methods, as described elsewhere in this book, but will also require more detailed study of transporters in their normal environment, perhaps by using patch-clamping or imaging techniques to study cells in situ.

Synthesis and processing of materials for direct thermal-to-electric energy conversion and storage

NASA Astrophysics Data System (ADS)

Thompson, Travis

thermogalvanic devices. Although thermogalvanic devices are known, there has been little exploration into the use of thermogalvanic devices for power generation and energy storage. First, this work formalizes the energy problem and introduces the operating principles of thermoelectric, galvanic, and thermogalvanic devices. Second, oxide based thermoelectric materials are explored from a synthetic and processing standpoint. Out of necessity, a new synthetic technique was invented and a novel hot-press technique was developed. Third, a solid Li-ion conducting electrolyte, based on the garnet crystal structure, is identified for the use in a thermogalvanic cell. In order to better understand the conductivity behavior, an in-depth exploration into the variables that control the ionic transport is performed on the electrolyte. Third, a thermogalvanic cell is constructed using this garnet based Li-ion conducting solid electrolyte and the first demonstration of such a cell is presented. Finally, strategies to improve the performance of thermogalvanic cells based on garnet type solid electrolytes are outlined for future work. The purpose of this work is to use an interdisciplinary approach to marry together the electrochemistry of galvanic systems with the strategies used to better semiconductor based thermoelectric materials and ceramics processing techniques to fabricate these systems. This dissertation will explore the interplay of these areas.

Separation of concanavalin A-induced human suppressor and helper T cells by the autologous erythrocyte rosette technique.

PubMed

Sakane, T; Honda, M; Taniguchi, Y; Kotani, H

1981-08-01

Very few normal human peripheral blood T cells are capable of binding autologous erythrocytes to form rosettes, whereas in the T cell population activated by concanavalin A (Con A) the autorosette levels are markedly enhanced. Fractionation of the Con A-activated T cells with autologous erythrocytes into autorosetting and nonrosetting cells demonstrates that suppressor, but not helper, activity resides in the autorosetting population, whereas the reverse is true of the nonrosetting population. Both these activities are found to be Con A dependent. The Con A-induced human suppressor cells can be identified and separated from the Con A-induced human helper cells by the autorosette technique. Studies on the surface properties of autorosetting and nonrosetting T cells indicate that there is little correlation between the activated suppressor and helper T cell subsets defined by autorosette technique and either those defined by monoclonal antibodies (which are able to distinguish these subsets in the resting but not activated T cells) or those defined by Fc receptors. Since the autorosetting T cell population (which acts as suppressor cells) bears receptors for peanut agglutinin, the nature of Con A-induced human suppressor cells appears to be analogous to that of Con A-induced murine suppressor cells.

Chapter 18: the origins of functional brain imaging in humans.

PubMed

Raichle, Marcus E

2010-01-01

Functional brain imaging in humans as we presently know it began when the experimental strategies of cognitive psychology were combined with modern brain imaging techniques, first positron emission tomography (PET) and then functional magnetic resonance imaging (fMRI), to examine how brain function supports mental activities. This marriage of disciplines and techniques galvanized the field of cognitive neuroscience, which has rapidly expanded to include a broad range of the social sciences as well as basic scientists interested in the neurophysiology, cell biology and genetics of the imaging signals. While much of this work has transpired over the past couple of decades, its roots can be traced back more than a century.

Toxicity screening of waste products using cell culture techniques

DOE Office of Scientific and Technical Information (OSTI.GOV)

Petitmermet, M.; Favre, A.; Shah, B.

1995-12-31

More than 600,000 tons of residue from waste incineration plants is produced in Switzerland each year. These residues are slag, fly ashes, and residues from extended flue gas cleaning. Because they are contaminated with heavy metals, they have to be deposited in appropriate landfills. Due to the increasing amount of municipal and industrial waste and the decreasing amount of disposal sites, additional treatment of waste and its by-products is becoming more and more important. To decrease the amount of residuals to be deposited, the heavy metal content of the residues has to be reduced by physical, chemical, or biological methodsmore » to acceptably low levels to obtain products suitable for reuse in the construction industry. The cell reactions due to the presence of residues and their extracts were studied using quantitative and qualitative methods. The results of the applied cell culture techniques showed that fly ash was much more cytotoxic than slag. This finding correlates with the chemical analysis. The washed samples were again less cytotoxic than their corresponding unwashed samples due to the lack of water-soluble compounds. The very sensitive response of the cell cultures to toxic substances was used to classify and validate the applied treatment methods.« less

Correlation of open cell-attached and excised patch clamp techniques.

PubMed

Filipovic, D; Hayslett, J P

1995-11-01

The excised patch clamp configuration provides a unique technique for some types of single channel analyses, but maintenance of stable, long-lasting preparations may be confounded by rundown and/or rapid loss of seal. Studies were performed on the amiloride-sensitive Na+ channel, located on the apical surface of A6 cells, to determine whether the nystatin-induced open cell-attached patch could serve as an alternative configuration. Compared to excised inside-out patches, stable preparations were achieved more readily with the open cell-attached patch (9% vs. 56% of attempts). In both preparations, the current voltage (I-V) relation was linear, current amplitudes were equal at opposite equivalent clamped voltages, and Erev was zero in symmetrical Na+ solutions, indicating similar Na+ activities on the cytosolic and external surfaces of the patch. Moreover, there was no evidence that nystatin altered channel activity in the patch because slope conductance (3-4pS) and Erev (75 mV), when the bath was perfused with a high K:low Na solution (ENa = 80 mV), were nearly equal in both patch configurations. Our results therefore indicate that the nystatin-induced open cell-attached patch can serve as an alternative approach to the excised inside-out patch when experiments require modulation of univalent ions in the cytosol.

Galvanic vestibular stimulation combines with Earth-horizontal rotation in roll to induce the illusion of translation.

PubMed

Schneider, Erich; Bartl, Klaus; Glasauer, Stefan

2009-05-01

Human head rotation in roll around an earth-horizontal axis constitutes a vestibular stimulus that, by its rotational component, acts on the semicircular canals (SCC) and that, by its tilt of the gravity vector, also acts on the otoliths. Galvanic vestibular stimulation (GVS) is thought to resemble mainly a rotation in roll. A superposition of sinusoidal GVS with a natural earth-horizontal roll movement was therefore applied in order to cancel the rotation effects and to isolate the otolith activation. By self-adjusting the amplitude and phase of GVS, subjects were able to minimize their sensation of rotation and to generate the perception of a linear translation. The final adjustments are in the range of a model that predicts SCC activation during natural rotations and GVS. This indicates that the tilt-translation ambiguity of the otoliths is resolved by SCC-otolith interaction. It is concluded that GVS might be able to cancel rotations in roll and that the residual tilt of the gravitoinertial force is possibly interpreted as a linear translation.

Electrical exposure analysis of galvanic-coupled intra-body communication based on the empirical arm models.

PubMed

Gao, Yue-Ming; Zhang, Heng-Fei; Lin, Shi; Jiang, Rui-Xin; Chen, Zhi-Ying; Lučev Vasić, Željka; Vai, Mang-I; Du, Min; Cifrek, Mario; Pun, Sio-Hang

2018-06-05

Intra-body communication (IBC) is one of the highlights in studies of body area networks. The existing IBC studies mainly focus on human channel characteristics of the physical layer, transceiver design for the application, and the protocol design for the networks. However, there are few safety analysis studies of the IBC electrical signals, especially for the galvanic-coupled type. Besides, the human channel model used in most of the studies is just a multi-layer homocentric cylinder model, which cannot accurately approximate the real human tissue layer. In this paper, the empirical arm models were established based on the geometrical information of six subjects. The thickness of each tissue layer and the anisotropy of muscle were also taken into account. Considering the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines, the restrictions taken as the evaluation criteria were the electric field intensity lower than 1.35 × 10 4 f V/m and the specific absorption rate (SAR) lower than 4 W/kg. The physiological electrode LT-1 was adopted in experiments whose size was 4 × 4 cm and the distance between each center of adjoining electrodes was 6 cm. The electric field intensity and localized SAR were all computed by the finite element method (FEM). The electric field intensity was set as average value of all tissues, while SAR was averaged over 10 g contiguous tissue. The computed data were compared with the 2010 ICNIRP guidelines restrictions in order to address the exposure restrictions of galvanic-coupled IBC electrical signals injected into the body with different amplitudes and frequencies. The input alternating signal was 1 mA current or 1 V voltage with the frequency range from 10 kHz to 1 MHz. When the subject was stimulated by a 1 mA alternating current, the average electric field intensity of all subjects exceeded restrictions when the frequency was lower than 20 kHz. The maximum difference among six subjects

Characterization and Prediction of Cracks in Coated Materials: Direction and Length of Crack Propagation in Bimaterials

PubMed Central

Azari, Z.; Pappalettere, C.

2015-01-01

The behaviour of materials is governed by the surrounding environment. The contact area between the material and the surrounding environment is the likely spot where different forms of degradation, particularly rust, may be generated. A rust prevention treatment, like bluing, inhibitors, humidity control, coatings, and galvanization, will be necessary. The galvanization process aims to protect the surface of the material by depositing a layer of metallic zinc by either hot-dip galvanizing or electroplating. In the hot-dip galvanizing process, a metallic bond between steel and metallic zinc is obtained by immersing the steel in a zinc bath at a temperature of around 460°C. Although the hot-dip galvanizing procedure is recognized to be one of the most effective techniques to combat corrosion, cracks can arise in the intermetallic δ layer. These cracks can affect the life of the coated material and decrease the lifetime service of the entire structure. In the present paper the mechanical response of hot-dip galvanized steel submitted to mechanical loading condition is investigated. Experimental tests were performed and corroborative numerical and analytical methods were then applied in order to describe both the mechanical behaviour and the processes of crack/cracks propagation in a bimaterial as zinc-coated material. PMID:27347531

Characterization and Prediction of Cracks in Coated Materials: Direction and Length of Crack Propagation in Bimaterials.

PubMed

Pruncu, C I; Azari, Z; Casavola, C; Pappalettere, C

2015-01-01

The behaviour of materials is governed by the surrounding environment. The contact area between the material and the surrounding environment is the likely spot where different forms of degradation, particularly rust, may be generated. A rust prevention treatment, like bluing, inhibitors, humidity control, coatings, and galvanization, will be necessary. The galvanization process aims to protect the surface of the material by depositing a layer of metallic zinc by either hot-dip galvanizing or electroplating. In the hot-dip galvanizing process, a metallic bond between steel and metallic zinc is obtained by immersing the steel in a zinc bath at a temperature of around 460°C. Although the hot-dip galvanizing procedure is recognized to be one of the most effective techniques to combat corrosion, cracks can arise in the intermetallic δ layer. These cracks can affect the life of the coated material and decrease the lifetime service of the entire structure. In the present paper the mechanical response of hot-dip galvanized steel submitted to mechanical loading condition is investigated. Experimental tests were performed and corroborative numerical and analytical methods were then applied in order to describe both the mechanical behaviour and the processes of crack/cracks propagation in a bimaterial as zinc-coated material.

Sensibilization of polymer/fullerene photovoltaic cells using Zinc Phtalocyanine studied by combinatorial technique

NASA Astrophysics Data System (ADS)

Godovsky, D.; Chen, L.; Petterson, L.; Inganäs, O.

2000-11-01

The influence of Zinc Phtalocyanine admixture to fullerene layers on top of PTOPT to the photovoltaic cells performance was studied. In order to investigate all the possible combinations of ZnPc and C60 the combinatorial technique was developed consisting in thermal co-evaporation of ZnPc and C60 from two different boats. The significant increase in solar cells photocurrent was observed, coming from ZnPc absorbance bands, especially for the layers containing 1:1 molar ratio of the components.

Analysis of the Growth Process of Neural Cells in Culture Environment Using Image Processing Techniques

NASA Astrophysics Data System (ADS)

Mirsafianf, Atefeh S.; Isfahani, Shirin N.; Kasaei, Shohreh; Mobasheri, Hamid

Here we present an approach for processing neural cells images to analyze their growth process in culture environment. We have applied several image processing techniques for: 1- Environmental noise reduction, 2- Neural cells segmentation, 3- Neural cells classification based on their dendrites' growth conditions, and 4- neurons' features Extraction and measurement (e.g., like cell body area, number of dendrites, axon's length, and so on). Due to the large amount of noise in the images, we have used feed forward artificial neural networks to detect edges more precisely.

Bioavailability of zinc in two zinc sulfate by-products of the galvanizing industry.

PubMed

Edwards, H M; Boling, S D; Emmert, J L; Baker, D H

1998-10-01

Two Zn depletion/repletion assays were conducted with chicks to determine the relative bioavailability (RBV) of Zn from two new by-products of the galvanizing industry. Using a soy concentrate-dextrose diet, slope-ratio methodology was employed to evaluate two different products: Fe-ZnSO4 x H2O with 20.2% Fe and 13.0% Zn, and Zn-FeSO4 x H2O with 14.2% Fe and 20.2% Zn. Feed-grade ZnSO4 x H2O was used as a standard. Weight gain, tibia Zn concentration, and total tibia Zn responded linearly (P < 0.01) to Zn supplementation from all three sources. Slope-ratio calculations based on weight gain established average Zn RBV values of 98% for Fe-ZnSO4 x H2O and 102% for Zn-FeSO4 x H2O, and these values were not different (P > 0.10) from the ZnSO4 standard (100%). Slope-ratio calculations based on total tibia Zn established average Zn RBV values of 126% for Fe-ZnSO4 x H2O and 127% for Zn-FeSO4 x H2O, and these values were greater (P < 0.01) than those of the ZnSO4 standard (100%). It is apparent that both mixed sulfate products of Fe and Zn are excellent sources of bioavailable Zn.

Using wavelet denoising and mathematical morphology in the segmentation technique applied to blood cells images.

PubMed

Boix, Macarena; Cantó, Begoña

2013-04-01

Accurate image segmentation is used in medical diagnosis since this technique is a noninvasive pre-processing step for biomedical treatment. In this work we present an efficient segmentation method for medical image analysis. In particular, with this method blood cells can be segmented. For that, we combine the wavelet transform with morphological operations. Moreover, the wavelet thresholding technique is used to eliminate the noise and prepare the image for suitable segmentation. In wavelet denoising we determine the best wavelet that shows a segmentation with the largest area in the cell. We study different wavelet families and we conclude that the wavelet db1 is the best and it can serve for posterior works on blood pathologies. The proposed method generates goods results when it is applied on several images. Finally, the proposed algorithm made in MatLab environment is verified for a selected blood cells.

Single-cell force spectroscopy as a technique to quantify human red blood cell adhesion to subendothelial laminin.

PubMed

Maciaszek, Jamie L; Partola, Kostyantyn; Zhang, Jing; Andemariam, Biree; Lykotrafitis, George

2014-12-18

Single-cell force spectroscopy (SCFS), an atomic force microscopy (AFM)-based assay, enables quantitative study of cell adhesion while maintaining the native state of surface receptors in physiological conditions. Human healthy and pathological red blood cells (RBCs) express a large number of surface proteins which mediate cell-cell interactions, or cell adhesion to the extracellular matrix. In particular, RBCs adhere with high affinity to subendothelial matrix laminin via the basal cell adhesion molecule and Lutheran protein (BCAM/Lu). Here, we established SCFS as an in vitro technique to study human RBC adhesion at baseline and following biochemical treatment. Using blood obtained from healthy human subjects, we recorded adhesion forces from single RBCs attached to AFM cantilevers as the cell was pulled-off of substrates coated with laminin protein. We found that an increase in the overall cell adhesion measured via SCFS is correlated with an increase in the resultant total force measured on 1 µm(2) areas of the RBC membrane. Further, we showed that SCFS can detect significant changes in the adhesive response of RBCs to modulation of the cyclic adenosine monophosphate (cAMP) and protein kinase A (PKA) pathway. Lastly, we identified variability in the RBC adhesion force to laminin amongst the human subjects, suggesting that RBCs maintain diverse levels of active BCAM/Lu adhesion receptors. By using single-cell measurements, we established a powerful new method for the quantitative measurement of single RBC adhesion with specific receptor-mediated binding. Copyright © 2014 Elsevier Ltd. All rights reserved.

Electromotive force measurements on cells involving beta-alumina solid electrolyte

NASA Technical Reports Server (NTRS)

Choudhury, N. S.

1973-01-01

Open-circuit emf measurements have been made to demonstrate that a two-phase, polycrystalline mixture of beta-alumina and alpha-alumina could be used as a solid electrolyte in galvanic cells with reversible electrodes fixing oxygen or aluminum chemical potentials. These measurements indicate that such a two-phase solid electrolyte may be used to monitor oxygen chemical potentials as low as that corresponding to Al and Al2O3 coexistence (potentials of about 10 to the minus 47th power atm at 1000 K). The activity of Na2O in beta-alumina in coexistence with alpha-alumina was also determined by emf measurements.

Cell Phone Detection Techniques

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pratt, Richard M.; Bunch, Kyle J.; Puzycki, David J.

2007-10-01

A team composed of Rick Pratt, Dave Puczyki, Kyle Bunch, Ryan Slaugh, Morris Good, and Doug McMakin teamed together to attempt to exploit cellular telephone features and detect if a person was carrying a cellular telephone into a Limited Area. The cell phone’s electromagnetic properties were measured, analyzed, and tested in over 10 different ways to determine if an exploitable signature exists. The method that appears to have the most potential for success without adding an external tag is to measure the RF spectrum, not in the cell phone band, but between 240 and 400MHz. Figures 1- 7 show themore » detected signal levels from cell phones from three different manufacturers.« less

Detection, manipulation and post processing of circulating tumor cells using optical techniques

NASA Astrophysics Data System (ADS)

Bakhtiaridoost, Somayyeh; Habibiyan, Hamidreza; Ghafoorifard, Hassan

2015-12-01

Circulating tumor cells (CTCs) are malignant cells that are derived from a solid tumor in the metastasis stage and are shed into the blood stream. These cells hold great promise to be used as liquid biopsy that is less aggressive than traditional biopsy. Recently, detection and enumeration of these cells has received ever-increasing attention from researchers as a way of early detection of cancer metastasis, determining the effectiveness of treatment and studying the mechanism of formation of secondary tumors. CTCs are found in blood at low concentration, which is a major limitation of isolation and detection of these cells. Over the last few years, multifarious research studies have been conducted on accurate isolation and detection and post processing of CTCs. Among all the proposed systems, microfluidic systems seem to be more attractive for researchers due to their numerous advantages. On the other hand, recent developments in optical methods have made the possibility of cellular studies at single-cell level. Thus, accuracy and efficiency of separation, detection and manipulation of CTCs can be improved using optical techniques. In this review, we describe optical methods that have been used for CTC detection, manipulation and post processing.

The continued promise of stem cell therapy in regenerative medicine.

PubMed

Eve, David J

2011-12-01

The use of stem cells is galvanizing regenerative medicine research. An analysis of recent trends as typified by articles published between 2009 and 2010 in the journals Cell Transplantation--The Regenerative Medicine Journal and Medical Science Monitor demonstrate the increasing importance of stem cell research as being on the cutting edge of regenerative medicine research. The analysis revealed an even split between transplantation and non-transplantation studies, showing that both the applicability and general research is being pursued. New methods and tissue engineering are also highly important components of regenerative medicine as demonstrated by a number of the stem cell studies being involved with either ex vivo manipulation, or cotransplantation with other cells or biomaterials. This suggests that the best results may be achieved with adjuvant therapies. The non-transplantation studies were more focused on manipulation of transplantable agents including cells and scaffold systems, as well as the use of medicines and dietary supplements. The further elucidation of disease mechanisms was a major contribution. This analysis suggests that regenerative medicine is proceeding at a rapid pace and the next few years should be of considerable interest with the initial results of pioneering stem cell therapies being announced.

Purification of Drug Loaded PLGA Nanoparticles Prepared by Emulsification Solvent Evaporation Using Stirred Cell Ultrafiltration Technique.

PubMed

Paswan, Suresh K; Saini, T R

2017-12-01

The emulsifiers in an exceedingly higher level are used in the preparation of drug loaded polymeric nanoparticles prepared by emulsification solvent evaporation method. This creates great problem to the formulator due to their serious toxicities when it is to be administered by parenteral route. The final product is therefore required to be freed from the used surfactants by the conventional purification techniques which is a cumbersome job. The solvent resistant stirred cell ultrafiltration unit (Millipore) was used in this study using polyethersulfone ultrafiltration membrane (Biomax®) having pore size of NMWL 300 KDa as the membrane filter. The purification efficiency of this technique was compared with the conventional centrifugation technique. The flow rate of ultrafiltration was optimized for removal of surfactant (polyvinyl alcohol) impurities to the acceptable levels in 1-3.5 h from the nanoparticle dispersion of tamoxifen prepared by emulsification solvent evaporation method. The present investigations demonstrate the application of solvent resistant stirred cell ultrafiltration technique for removal of toxic impurities of surfactant (PVA) from the polymeric drug nanoparticles (tamoxifen) prepared by emulsification solvent evaporation method. This technique offers added benefit of producing more concentrated nanoparticles dispersion without causing significant particle size growth which is observed in other purification techniques, e.g., centrifugation and ultracentrifugation.

In situ cell culture monitoring on a Ti-6Al-4V surface by electrochemical techniques.

PubMed

García-Alonso, M C; Saldaña, L; Alonso, C; Barranco, V; Muñoz-Morris, M A; Escudero, M L

2009-05-01

In this work, the in situ interaction between Ti-6Al-4V alloy and osteoblastic cells has been studied by electrochemical techniques as a function of time. The interaction has been monitored for cell adhesion and growth of human osteoblastic Saos-2 cells on Ti-6Al-4V samples. The study has been carried out by electrochemical techniques, e.g., studying the evolution of corrosion potential with exposure time and by electrochemical impedance spectroscopy. The impedance results have been analyzed by using different equivalent circuit models that simulate the interface state at each testing time. The adhesion of the osteoblastic cells on the Ti-6Al-4V alloy leads to surface areas with different cell coverage rates, thus showing the different responses in the impedance diagrams with time. The effect of the cells on the electrochemical response of Ti-6Al-4V alloy is clearly seen after 4 days of testing, in which two isolated and well-differentiated time constants are clearly observed. One of these is associated with the presence of the cells and the other with a passive film on the Ti-6Al-4V alloy. After 7 days of culture, the system is governed by a resistive component over a wide frequency range which is associated with an increase in the cell coverage rate on the surface due to the extracellular matrix.

Embedded 32-bit Differential Pulse Voltammetry (DPV) Technique for 3-electrode Cell Sensing

NASA Astrophysics Data System (ADS)

N, Aqmar N. Z.; Abdullah, W. F. H.; Zain, Z. M.; Rani, S.

2018-03-01

This paper addresses the development of differential pulse voltammetry (DPV) embedded algorithm using an ARM cortex processor with new developed potentiostat circuit design for in-situ 3-electrode cell sensing. This project is mainly to design a low cost potentiostat for the researchers in laboratories. It is required to develop an embedded algorithm for analytical technique to be used with the designed potentiostat. DPV is one of the most familiar pulse technique method used with 3-electrode cell sensing in chemical studies. Experiment was conducted on 10mM solution of Ferricyanide using the designed potentiostat and the developed DPV algorithm. As a result, the device can generate an excitation signal of DPV from 0.4V to 1.2V and produced a peaked voltammogram with relatively small error compared to the commercial potentiostat; which is only 6.25% difference in peak potential reading. The design of potentiostat device and its DPV algorithm is verified.

Development of an invitro technique to use mouse embryonic stem cell in evaluating effects of xenobiotics

EPA Science Inventory

Our goal has been to develop a high-throughput, in vitro technique for evaluating the effects of xenobiotics using mouse embryonic stem cells (mESCs). We began with the Embryonic Stem Cell Test (EST), which is used to predict the embryotoxic potential of a test compound by combin...

A Historical Perspective on the Identification of Cell Types in Pancreatic Islets of Langerhans by Staining and Histochemical Techniques

PubMed Central

2015-01-01

Before the middle of the previous century, cell types of the pancreatic islets of Langerhans were identified primarily on the basis of their color reactions with histological dyes. At that time, the chemical basis for the staining properties of islet cells in relation to the identity, chemistry and structure of their hormones was not fully understood. Nevertheless, the definitive islet cell types that secrete glucagon, insulin, and somatostatin (A, B, and D cells, respectively) could reliably be differentiated from each other with staining protocols that involved variations of one or more tinctorial techniques, such as the Mallory-Heidenhain azan trichrome, chromium hematoxylin and phloxine, aldehyde fuchsin, and silver impregnation methods, which were popularly used until supplanted by immunohistochemical techniques. Before antibody-based staining methods, the most bona fide histochemical techniques for the identification of islet B cells were based on the detection of sulfhydryl and disulfide groups of insulin. The application of the classical islet tinctorial staining methods for pathophysiological studies and physiological experiments was fundamental to our understanding of islet architecture and the physiological roles of A and B cells in glucose regulation and diabetes. PMID:26216133

Tailoring galvanic replacement reaction for the preparation of Pt/Ag bimetallic hollow nanostructures with controlled number of voids.

PubMed

Zhang, Weiqing; Yang, Jizheng; Lu, Xianmao

2012-08-28

Here we report the synthesis of Pt/Ag bimetallic nanostructures with controlled number of void spaces via a tailored galvanic replacement reaction (GRR). Ag nanocubes (NCs) were employed as the template to react with Pt ions in the presence of HCl. The use of HCl in the GRR caused rapid precipitation of AgCl, which grew on the surface of Ag NCs and acted as a removable secondary template for the deposition of Pt. The number of nucleation sites for AgCl was tailored by controlling the amount of HCl added to the Ag NCs or by introducing PVP to the reaction. This strategy led to the formation of Pt/Ag hollow nanoboxes, dimers, multimers, or popcorn-shaped nanostructures consisting of one, two, or multiple hollow domains. Due to the presence of large void space and porous walls, these nanostructures exhibited high surface area and improved catalytic activity for methanol oxidation reaction.

Research Techniques Made Simple: Single-Cell RNA Sequencing and its Applications in Dermatology.

PubMed

Wu, Xiaojun; Yang, Bin; Udo-Inyang, Imo; Ji, Suyun; Ozog, David; Zhou, Li; Mi, Qing-Sheng

2018-05-01

RNA sequencing is one of the most highly reliable and reproducible methods of assessing the cell transcriptome. As high-throughput RNA sequencing libraries at the single cell level have recently developed, single cell RNA sequencing has become more feasible and popular in biology research. Single cell RNA sequencing allows investigators to evaluate cell transcriptional profiles at the single cell level. It has become a very useful tool to perform investigations that could not be addressed by other methodologies, such as the assessment of cell-to-cell variation, the identification of rare populations, and the determination of heterogeneity within a cell population. So far, the single cell RNA sequencing technique has been widely applied to embryonic development, immune cell development, and human disease progress and treatment. Here, we describe the history of single cell technology development and its potential application in the field of dermatology. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

The mechanical properties and microstructures of vanadium bearing high strength dual phase steels processed with continuous galvanizing line simulations

NASA Astrophysics Data System (ADS)

Gong, Yu

For galvanized or galvannealed steels to be commercially successful, they must exhibit several attributes: (i) easy and inexpensive processing in the hot mill, cold mill and on the coating line, (ii) high strength with good formability and spot weldability, and (iii) good corrosion resistance. At the beginning of this thesis, compositions with a common base but containing various additions of V or Nb with or without high N were designed and subjected to Gleeble simulations of different galvanizing(GI), galvannealing(GA) and supercooling processing. The results revealed the phase balance was strongly influenced by the different microalloying additions, while the strengths of each phase were somewhat less affected. Our research revealed that the amount of austenite formed during intercritical annealing can be strongly influenced by the annealing temperature and the pre-annealing conditions of the hot band (coiling temperature) and cold band (% cold reduction). In the late part of this thesis, the base composition was a low carbon steel which would exhibit good spot weldability. To this steel were added two levels of Cr and Mo for strengthening the ferrite and increasing the hardenability of intercritically formed austenite. Also, these steels were produced with and without the addition of vanadium in an effort to further increase the strength. Since earlier studies revealed a relationship between the nature of the starting cold rolled microstructure and the response to CGL processing, the variables of hot band coiling temperature and level of cold reduction prior to annealing were also studied. Finally, in an effort to increase strength and ductility of both the final sheet (general formability) and the sheared edges of cold punched holes (local formability), a new thermal path was developed that replaced the conventional GI ferrite-martensite microstructure with a new ferrite-martensite-tempered martensite and retained austenite microstructure. The new

Flow and transport due to natural convection in a galvanic cell. 1: Development of a mathematical model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Siu, S.; Evans, J.W.

1997-08-01

In many electrochemical cells, the flow of electrolyte has an influence on cell behavior and this investigation concerns a cell (a zinc-air cell) where that flow occurred through natural convection. The zinc was present in the form of a bed of particles, connected at its top and bottom with channels forming reservoirs of electrolyte. Dissolution of the zinc caused density differences between electrolyte in the bed interstices and that in the reservoir. In Part 1 of this two-part paper, a mathematical model for this cell is developed. The model employs the well-known Newman/Tobias description of a porous electrode and treatsmore » flow through the bed using the Blake-Kozeny equation. A fourth-order Lax-Wendroff algorithm, thought to be original, is used to solve the convective diffusion equation within the model. Sample computed results are presented.« less

Influence of galvanic vestibular stimulation on egocentric and object-based mental transformations.

PubMed

Lenggenhager, Bigna; Lopez, Christophe; Blanke, Olaf

2008-01-01

The vestibular system analyses angular and linear accelerations of the head that are important information for perceiving the location of one's own body in space. Vestibular stimulation and in particular galvanic vestibular stimulation (GVS) that allow a systematic modification of vestibular signals has so far mainly been used to investigate vestibular influence on sensori-motor integration in eye movements and postural control. Comparatively, only a few behavioural and imaging studies have investigated how cognition of space and body may depend on vestibular processing. This study was designed to differentiate the influence of left versus right anodal GVS compared to sham stimulation on object-based versus egocentric mental transformations. While GVS was applied, subjects made left-right judgments about pictures of a plant or a human body presented at different orientations in the roll plane. All subjects reported illusory sensations of body self-motion and/or visual field motion during GVS. Response times in the mental transformation task were increased during right but not left anodal GVS for the more difficult stimuli and the larger angles of rotation. Post-hoc analyses suggested that the interfering effect of right anodal GVS was only present in subjects who reported having imagined turning themselves to solve the mental transformation task (egocentric transformation) as compared to those subjects having imagined turning the picture in space (object-based mental transformation). We suggest that this effect relies on shared functional and cortical mechanisms in the posterior parietal cortex associated with both right anodal GVS and mental imagery.

Techniques for 3D tracking of single molecules with nanometer accuracy in living cells

NASA Astrophysics Data System (ADS)

Gardini, Lucia; Capitanio, Marco; Pavone, Francesco S.

2013-06-01

We describe a microscopy technique that, combining wide-field single molecule microscopy, bifocal imaging and Highly Inclined and Laminated Optical sheet (HILO) microscopy, allows a 3D tracking with nanometer accuracy of single fluorescent molecules in vitro and in living cells.

Identification of techniques to meet pH standard during in-stream construction : research summary.

DOT National Transportation Integrated Search

2014-03-01

Many of Marylands tributaries traverse highway infrastructure via culverts that are managed : and maintained by SHA. These culverts are often made of galvanized steel and over time are : subjected to scour. Concrete grout is often used as a repair...

Development of a new low cost antireflective coating technique for solar cells

NASA Technical Reports Server (NTRS)

Wohlgemuth, J. H.; Warfield, D. B.; Johnson, G. A.

1982-01-01

The goal of this study was the development of an antireflective (AR) coating technique that has the potential for high throughput and low cost yet is capable of producing films of good optical quality. Previous efforts to develop sprayed AR coatings had utilized titanium isopropoxide mixed with volatile solvents. These films worked well on smooth surfaces but when applied to etched semi-crystalline silicon surfaces yielded inconsistent results with more than 20 percent of the AM1 incident light being reflected. In this program titanium isopropoxide was sprayed directly onto heater wafers (410 C) to produce a uniform AR coating even on highly textured surfaces. Tests on various types of solar cells yielded performance improvements for the hot sprayed AR cells that are equivalent to that observed for evaporated TiOx AR coated cells. As an extension of this effort a new double layer AR consisting of a bottom layer of hot sprayed titanium isopropoxide and a top layer of hot sprayed aluminum isopropoxide in methylene chloride has resulted in more than 10 percent improvement in cell output as compared to a single layer AR cell.

Development of 3D imaging technique of reconstructed human epidermis with immortalized human epidermal cell line.

PubMed

Inoue, Yu; Hasegawa, Seiji; Miyachi, Katsuma; Yamada, Takaaki; Nakata, Satoru; Ipponjima, Sari; Hibi, Terumasa; Nemoto, Tomomi; Tanaka, Masahiko; Suzuki, Ryo; Hirashima, Naohide

2018-05-01

The epidermis, the outermost layer of the skin, retains moisture and functions as a physical barrier against the external environment. Epidermal cells are continuously replaced by turnover, and thus to understand in detail the dynamic cellular events in the epidermis, techniques to observe live tissues in 3D are required. Here, we established a live 3D imaging technique for epidermis models. We first obtained immortalized human epidermal cell lines which have a normal differentiation capacity and fluorescence-labelled cytoplasm or nuclei. The reconstituted 3D epidermis was prepared with these lines. Using this culture system, we were able to observe the structure of the reconstituted epidermis live in 3D, which was similar to an in vivo epidermis, and evaluate the effect of a skin irritant. This technique may be useful for dermatological science and drug development. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Study for determination of industrial water corrosivity in Kashan Fajre Sepahan Galvanizing Mills during 2005-2006 Iran.

PubMed

Rabbani, D; Miranzadeh, M B; Motlagh, A Ahmadi

2008-01-01

This research was carried out in Kashan Fajre Sepahan Galvanizing mills (KFSGM) for evaluation of water corrosivity during 2005-2006. A total of 18 samples were taken from various points of the water supply system for testing the specific parameters and calculation Langelier Index (LI), Ryznar Index (RI) and Pukorious Index (PI). This research showed that in raw water (sand filter effluent) LI were positive as well as RI and PI were lower than 7 which means that mentioned water is not corrosive. Also LI in treated water by reverse osmosis process was negative and RI and PI were higher than 7, so, this water has corrosive properties. Finally, calculated indexes indicate that according to LI, conditioned water is not corrosive but based on RI and P. this water tend to corrosivity which this findings is compatible with literature review statement. So it is recommended that, for water conditioning addition of preservative chemicals to be continued but at the same time another alternatives such as pH adjustment, air stripping and deoxygenating, control of carbonate concentration and split flow treatment should be studied.

New designs and characterization techniques for thin-film solar cells

NASA Astrophysics Data System (ADS)

Pang, Yutong

This thesis presents a fundamentally new thin-film photovoltaic design and develops several novel characterization techniques that improve the accuracy of thin-film solar cell computational models by improving the accuracy of the input data. We first demonstrate a novel organic photovoltaic (OPV) design, termed a "Slot OPV", in which the active layer is less than 50 nm; We apply the principles of slot waveguides to confine light within the active layer. According to our calculation, the guided-mode absorption for a 10nm thick active layer equal to the absorption of normal incidence on an OPV with a 100nm thick active layer. These results, together with the expected improvement in charge extraction for ultrathin layers, suggest that slot OPVs can be designed with greater power conversion efficiency than today's state-of-art OPV architectures if practical challenges, such as the efficient coupling of light into these modes, can be overcome. The charge collection probability, i.e. the probability that charges generated by absorption of a photon are successfully collected as current, is a critical feature for all kinds of solar cells. While the electron-beam-induced current (EBIC) method has been used in the past to successfully reconstruct the charge collection probability, this approach is destructive and requires time-consuming sample preparation. We demonstrate a new nondestructive optoelectronic method to reconstruct the charge collection probability by analyzing the internal quantum efficiency (IQE) data that are measured on copper indium gallium diselenide (CIGS) thin-film solar cells. We further improve the method with a parameter-independent regularization approach. Then we introduce the Self-Constrained Ill-Posed Inverse Problem (SCIIP) method, which improves the signal-to-noise of the solution by using the regularization method with system constraints and optimization via an evolutionary algorithm. For a thin-film solar cell optical model to be an accurate

Color edges extraction using statistical features and automatic threshold technique: application to the breast cancer cells.

PubMed

Ben Chaabane, Salim; Fnaiech, Farhat

2014-01-23

Color image segmentation has been so far applied in many areas; hence, recently many different techniques have been developed and proposed. In the medical imaging area, the image segmentation may be helpful to provide assistance to doctor in order to follow-up the disease of a certain patient from the breast cancer processed images. The main objective of this work is to rebuild and also to enhance each cell from the three component images provided by an input image. Indeed, from an initial segmentation obtained using the statistical features and histogram threshold techniques, the resulting segmentation may represent accurately the non complete and pasted cells and enhance them. This allows real help to doctors, and consequently, these cells become clear and easy to be counted. A novel method for color edges extraction based on statistical features and automatic threshold is presented. The traditional edge detector, based on the first and the second order neighborhood, describing the relationship between the current pixel and its neighbors, is extended to the statistical domain. Hence, color edges in an image are obtained by combining the statistical features and the automatic threshold techniques. Finally, on the obtained color edges with specific primitive color, a combination rule is used to integrate the edge results over the three color components. Breast cancer cell images were used to evaluate the performance of the proposed method both quantitatively and qualitatively. Hence, a visual and a numerical assessment based on the probability of correct classification (PC), the false classification (Pf), and the classification accuracy (Sens(%)) are presented and compared with existing techniques. The proposed method shows its superiority in the detection of points which really belong to the cells, and also the facility of counting the number of the processed cells. Computer simulations highlight that the proposed method substantially enhances the segmented image

Metal catalyst technique for texturing silicon solar cells

DOEpatents

Ruby, Douglas S.; Zaidi, Saleem H.

2001-01-01

Textured silicon solar cells and techniques for their manufacture utilizing metal sources to catalyze formation of randomly distributed surface features such as nanoscale pyramidal and columnar structures. These structures include dimensions smaller than the wavelength of incident light, thereby resulting in a highly effective anti-reflective surface. According to the invention, metal sources present in a reactive ion etching chamber permit impurities (e.g. metal particles) to be introduced into a reactive ion etch plasma resulting in deposition of micro-masks on the surface of a substrate to be etched. Separate embodiments are disclosed including one in which the metal source includes one or more metal-coated substrates strategically positioned relative to the surface to be textured, and another in which the walls of the reaction chamber are pre-conditioned with a thin coating of metal catalyst material.

Identification and preliminary evaluation of polychlorinated naphthalene emissions from hot dip galvanizing plants.

PubMed

Liu, Guorui; Lv, Pu; Jiang, Xiaoxu; Nie, Zhiqiang; Liu, Wenbin; Zheng, Minghui

2015-01-01

Hot dip galvanizing (HDG) processes are sources of polychlorinated-p-dioxins and dibenzofurans (PCDD/Fs). Close correlations have been found between the concentration of PCDD/Fs and polychlorinated naphthalenes (PCNs) that are produced and released during industrial thermal processes. We speculated, therefore, that HDG plants are potential PCN sources. In this preliminary study, PCNs were analyzed in solid residues, ash and precipitate from three HDG plants of different sizes. The total PCN concentrations (∑2-8PCNs) in the residue samples ranged from 60.3 to 226pgg(-1). The PCN emission factors for the combined ash and precipitate residues from the HDG plants ranged from 75 to 178ngt(-1) for the dichlorinated and octachlorinated naphthalenes. The preliminary results suggested that the HDG industry might not currently be a significant source of PCN emissions. The trichloronaphthalenes were the dominant homologs followed by the dichloronaphthalenes and the tetrachloronaphthalenes. The PCN congeners CN37/33/34, CN52/60, CN66/67, and CN73 dominated the tetrachlorinated, pentachlorinated, hexachlorinated, and heptachlorinated naphthalene homologs, respectively. The PCNs emitted from the HDG plants had similar homolog distributions and congener profiles to the PCNs emitted from combustion plants and other metallurgical processes. The identification and preliminary evaluation of PCN emissions from HDG plants presented here will help in the prioritization of measures for controlling PCN emissions from industrial sources. Copyright © 2014 Elsevier Ltd. All rights reserved.

Laser Stimulated Genomic Exchange in Stem Cells. Laser Non-cloning Techniques

NASA Astrophysics Data System (ADS)

Stefan, V. Alexander

2012-02-01

I propose a novel technique for a pluripotent stem cell generation. Genomic exchange is stimulated by the beat-wave free electron laser, (B-W FEL), frequency matching with the frequencies of the DNAootnotetextJ.D. Watson and F. H. C. Crick, Nature, 171, 737-738 (1953). eigen-oscillations. B-W FEL-1ootnotetextV. Stefan, B.I.Cohen, C. Joshi Science, 243,4890, (Jan 27,1989); Stefan, et al., Bull. APS. 32, No. 9, 1713 (1987); Stefan, APS March-2011, #S1.143; APS- March-2009, #K1.276. scans entire stem cell; B-W FEL-2 probes the chromosomes. The scanning and probing lasers: 300-500nm and 100-300nm, respectively; irradiances: the order-of-10s mW/cm^2 (above the threshold value for a particular gene structure); repetition rate of few-100s Hz. A variety of genetic-matching conditions can be arranged. Genomic glitches, (the cell nucleus transferootnotetextScott Noggle et al. Nature, 478, 70-75 (06 October 2011).), can be hedged by the use of lasers.

Development of a cell culture surface conversion technique using alginate thin film for evaluating effect upon cellular differentiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nakashima, Y., E-mail: yuta-n@mech.kumamoto-u.ac.jp; Graduate School of Science and Engineering, Yamaguchi University, 2-16-1 Tokiwadai, Ube 755-8611; Tsusu, K.

2014-06-15

Here, we sought to develop a cell culture surface conversion technique that would not damage living cells. An alginate thin film, formed on a glass plate by spin coating of sodium alginate solution and dipping into calcium chloride solution, was used to inhibit adhesion of cells. The film could be removed by ethylenediaminetetraacetate (EDTA) at any time during cell culture, permitting observation of cellular responses to conversion of the culture surface in real time. Additionally, we demonstrated the validity of the alginate thin film coating method and the performance of the film. The thickness of the alginate thin film wasmore » controlled by varying the rotation speed during spin coating. Moreover, the alginate thin film completely inhibited the adhesion of cultured cells to the culture surface, irrespective of the thickness of the film. When the alginate thin film was removed from the culture surface by EDTA, the cultured cells adhered to the culture surface, and their morphology changed. Finally, we achieved effective differentiation of C2C12 myoblasts into myotube cells by cell culture on the convertible culture surface, demonstrating the utility of our novel technique.« less

Immunofluorescence Technique Using HeLa Cells Expressing Recombinant Nucleoprotein for Detection of Immunoglobulin G Antibodies to Crimean-Congo Hemorrhagic Fever Virus

PubMed Central

Saijo, Masayuki; Qing, Tang; Niikura, Masahiro; Maeda, Akihiko; Ikegami, Tetsuro; Sakai, Koji; Prehaud, Christophe; Kurane, Ichiro; Morikawa, Shigeru

2002-01-01

A HeLa cell line continuously expressing recombinant nucleoprotein (rNP) of the Crimean-Congo hemorrhagic fever virus (CCHFV) was established by transfection with an expression vector containing the cDNA of CCHFV NP (pKS336-CCHFV-NP). These cells were used as antigens for indirect immunofluorescence (IF) to detect immunoglobulin G antibodies to CCHFV. The sensitivity and specificity of this IF technique were examined by using serum samples and were compared to those of the IF technique using CCHFV-infected Vero E6 cells (authentic antigen). Staining of the CCHFV rNP expressed in HeLa cells showed a unique granular pattern similar to that of CCHFV-infected Vero E6 cells. Positive staining could easily be distinguished from a negative result. All 13 serum samples determined to be positive by using the authentic antigen were also determined to be positive by using CCHFV rNP-expressing HeLa cells (recombinant antigen). The 108 serum samples determined to be negative by using the authentic antigen were also determined to be negative by using the recombinant antigen. Thus, both the sensitivity and the specificity of this IF technique were 100% compared to the IF with authentic antigen. The novel IF technique using CCHFV rNP-expressing HeLa cells can be used not only for diagnosis of CCHF but also for epidemiological studies on CCHFV infections. PMID:11825944

Templated Atom-Precise Galvanic Synthesis and Structure Elucidation of a [Ag24Au(SR)18](-) Nanocluster.

PubMed

Bootharaju, Megalamane S; Joshi, Chakra P; Parida, Manas R; Mohammed, Omar F; Bakr, Osman M

2016-01-18

Synthesis of atom-precise alloy nanoclusters with uniform composition is challenging when the alloying atoms are similar in size (for example, Ag and Au). A galvanic exchange strategy has been devised to produce a compositionally uniform [Ag24Au(SR)18](-) cluster (SR: thiolate) using a pure [Ag25(SR)18](-) cluster as a template. Conversely, the direct synthesis of Ag24Au cluster leads to a mixture of [Ag(25-x)Au(x)(SR)18](-), x=1-8. Mass spectrometry and crystallography of [Ag24Au(SR)18](-) reveal the presence of the Au heteroatom at the Ag25 center, forming Ag24Au. The successful exchange of the central Ag of Ag25 with Au causes perturbations in the Ag25 crystal structure, which are reflected in the absorption, luminescence, and ambient stability of the particle. These properties are compared with those of Ag25 and Ag24Pd clusters with same ligand and structural framework, providing new insights into the modulation of cluster properties with dopants at the single-atom level. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Transmission electron microscopy characterization of the interfacial structure of a galvanized dual-phase steel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aslam, I., E-mail: ia31@msstate.edu

2016-10-15

Site-specific studies were carried out to characterize the interface of a galvanized dual-phase (DP) steel. Focused ion beam (FIB) was used to prepare specimens in the interface region (~ 100 nm thick) between the coating and the substrate. Transmission electron microscopy (TEM), scanning TEM (STEM), and high resolution TEM (HRTEM) were performed to resolve the phases and the structures at the interface between the zinc (Zn) coating and the steel substrate. The STEM and TEM results showed that a continuous manganese oxide (MnO) film with a thickness of ~ 20 nm was present on the surface of the substrate whilemore » no silicon (Si) oxides were resolved. Internal oxide particles were observed as well in the sub-surface region. Despite the presence of the continuous oxide film, a well-developed inhibition layer was observed right on top of the oxide film. The inhibition layer has a thickness of ~ 100 nm. Possible mechanisms for the growth of the inhibition layer were discussed. - Highlights: •Site-specific examinations were performed on the Zn/steel interface. •Continuous external MnO oxides (20 nm) were observed at the interface. •No Si oxides were observed at the interface. •Internal oxide particles were distributed in the subsurface. •A continuous inhibition layer grew on top of the external oxides.« less

A NOVEL TECHNIQUE FOR QUANTITATIVE ESTIMATION OF UPTAKE OF DIESEL EXHAUST PARTICLES BY LUNG CELLS

EPA Science Inventory

While airborne particulates like diesel exhaust particulates (DEP) exert significant toxicological effects on lungs, quantitative estimation of accumulation of DEP inside lung cells has not been reported due to a lack of an accurate and quantitative technique for this purpose. I...

Activation requirements and responses to TLR ligands in human CD4+ T cells: comparison of two T cell isolation techniques.

PubMed

Lancioni, Christina L; Thomas, Jeremy J; Rojas, Roxana E

2009-05-15

Direct regulation of T cell function by microbial ligands through Toll-like receptors (TLR) is an emerging area of T cell biology. Currently either immunomagnetic cell sorting (IMACS) or fluorescence-activated cell sorting (FACS), are utilized to isolate T-cell subsets for such studies. However, it is unknown to what extent differences in T cell purity between these isolation techniques influence T cell functional assays. We compared the purity, response to mitogen, activation requirements, and response to TLR ligands between human CD4(+) T cells isolated either by IMACS (IMACS-CD4(+)) or by IMACS followed by FACS (IMACS/FACS-CD4(+)). As expected, IMACS-CD4(+) were less pure than IMACS/FACS-CD4(+) (92.5%+/-1.4% versus 99.7%+/-0.2%, respectively). Consequently, IMACS-CD4(+) proliferated and produced cytokines in response to mitogen alone and had lower activation requirements compared to IMACS/FACS-CD4(+). In addition IMACS-CD4(+) but not IMACS/FACS-CD4(+) responses were upregulated by the TLR-4 ligand lipopolysaccharide (LPS). On the other hand, TLR-2 and TLR-5 engagement induced costimulation in both IMACS-CD4(+) and highly purified IMACS-/FACS-CD4(+). Altogether these results indicate that small differences in cell purity can significantly alter T cell responses to TLR ligands. This study stresses the importance of a stringent purification method when investigating the role of microbial ligands in T cell function.

Empirical gradient threshold technique for automated segmentation across image modalities and cell lines.

PubMed

Chalfoun, J; Majurski, M; Peskin, A; Breen, C; Bajcsy, P; Brady, M

2015-10-01

New microscopy technologies are enabling image acquisition of terabyte-sized data sets consisting of hundreds of thousands of images. In order to retrieve and analyze the biological information in these large data sets, segmentation is needed to detect the regions containing cells or cell colonies. Our work with hundreds of large images (each 21,000×21,000 pixels) requires a segmentation method that: (1) yields high segmentation accuracy, (2) is applicable to multiple cell lines with various densities of cells and cell colonies, and several imaging modalities, (3) can process large data sets in a timely manner, (4) has a low memory footprint and (5) has a small number of user-set parameters that do not require adjustment during the segmentation of large image sets. None of the currently available segmentation methods meet all these requirements. Segmentation based on image gradient thresholding is fast and has a low memory footprint. However, existing techniques that automate the selection of the gradient image threshold do not work across image modalities, multiple cell lines, and a wide range of foreground/background densities (requirement 2) and all failed the requirement for robust parameters that do not require re-adjustment with time (requirement 5). We present a novel and empirically derived image gradient threshold selection method for separating foreground and background pixels in an image that meets all the requirements listed above. We quantify the difference between our approach and existing ones in terms of accuracy, execution speed, memory usage and number of adjustable parameters on a reference data set. This reference data set consists of 501 validation images with manually determined segmentations and image sizes ranging from 0.36 Megapixels to 850 Megapixels. It includes four different cell lines and two image modalities: phase contrast and fluorescent. Our new technique, called Empirical Gradient Threshold (EGT), is derived from this reference

Cell-micropatterning by micromolding in capillary technique based on UV polymerization

NASA Astrophysics Data System (ADS)

Park, Min J.; Choi, Won M.; Park, O. O.

2006-01-01

Although optical lithography or photolithography is one of the most well-established techniques for micro, nano-fabrication, its usage with proteins and cells is restricted by steps that must be carried out in harsh organic solvents. Here, we present simple methods for cell-micropatterning using poly(dimethylsiloxane) (PDMS) as a mold. Cell non-adhesive surface or nonfouling surface providing a physico-chemical barrier to cell attachment was introduced for biomaterial pattering, where cells fail to interact with the surface over desired periods of time determined by each application. Poly(ethylene glycol) (PEG) was selected as nonfouling material to inhibit protein adsorption from biological media. The fouling resistance of PEG polymer is often explained by a steric repulsion interaction, resulting from the compression of PEG chains as proteins approach the surface. We also chose fibronectin to direct cell attachment because it is an extracellular matrix protein that is involved in the adhesion and spreading of anchorage-dependent cells. In our experiment, we propose two methods by application of micromolding in capillary (MIMIC) method based on UV polymerization to obtain a surface of alternating PEG and fibronectin. First to fabricate PEG microstructure via MIMIC method, a pre-patterned PDMS mold is placed on a desired substrate, and then the relief structure in the mold forms a network of empty channels. A drop of ethylene glycol monomer solution containing initiator for UV polymerization is placed at the open ends of the network of channels, which is then polymerized by exposure to UV light at room temperature. Once PEG microstructure is fabricated, incubation of the patterned surface in a fibronectin-containing solution allows back-filling of only the bare regions with fibronectin via adsorption. In the alternative method, a substrate is first incubated in a fibronectin-containing solution, leading to the adsorption of fibronectin over the entire surface, and

Screening for stroke in sickle cell anemia: comparison of transcranial Doppler imaging and nonimaging US techniques.

PubMed

Neish, Ariane S; Blews, David E; Simms, Catherine A; Merritt, Robert K; Spinks, Alice J

2002-03-01

To determine whether criteria for screening patients with sickle cell anemia for stroke established with a nonimaging transcranial Doppler ultrasonographic (US) technique are applicable to studies performed with a transcranial Doppler US imaging technique. One hundred sixty-eight examinations in 66 children were performed for sickle cell stroke screening. Children were examined with nonimaging and imaging transcranial Doppler US techniques on the same day, for a total of 84 paired examinations. The time-averaged maximum mean velocity (V(mean)) and resistive index (RI) were calculated in the middle cerebral arteries, bifurcations of the distal internal carotid arteries, distal internal carotid arteries, anterior cerebral arteries, posterior cerebral arteries, and basilar arteries. The maximum systolic velocity (V(max)) was evaluated in the distal internal carotid arteries and middle cerebral arteries. V(mean), V(max), and RI measurements were subjected to repeated-measures multivariate analysis of covariance, and the Pearson product moment correlation was used for middle cerebral artery velocity, age, and hemoglobin. V(mean) measurements obtained with nonimaging and imaging techniques varied substantially for the bifurcation of the distal internal carotid artery, the posterior cerebral artery, and the basilar artery. Substantial differences were found in RIs for every vessel. Examination time was shorter with the nonimaging technique. V(mean) measurements in the middle cerebral artery, distal internal carotid artery, and anterior cerebral artery did not vary substantially between nonimaging and imaging transcranial Doppler US. RI data did not yield comparable measurements.

Effect of dual laser beam on dissimilar welding-brazing of aluminum to galvanized steel

NASA Astrophysics Data System (ADS)

Mohammadpour, Masoud; Yazdian, Nima; Yang, Guang; Wang, Hui-Ping; Carlson, Blair; Kovacevic, Radovan

2018-01-01

In this investigation, the joining of two types of galvanized steel and Al6022 aluminum alloy in a coach peel configuration was carried out using a laser welding-brazing process in dual-beam mode. The feasibility of this method to obtain a sound and uniform brazed bead with high surface quality at a high welding speed was investigated by employing AlSi12 as a consumable material. The effects of alloying elements on the thickness of intermetallic compound (IMC) produced at the interface of steel and aluminum, surface roughness, edge straightness and the tensile strength of the resultant joint were studied. The comprehensive study was conducted on the microstructure of joints by means of a scanning electron microscopy and EDS. Results showed that a dual-beam laser shape and high scanning speed could control the thickness of IMC as thin as 3 μm and alter the failure location from the steel-brazed interface toward the Al-brazed interface. The numerical simulation of thermal regime was conducted by the Finite Element Method (FEM), and simulation results were validated through comparative experimental data. FEM thermal modeling evidenced that the peak temperatures at the Al-steel interface were around the critical temperature range of 700-900 °C that is required for the highest growth rate of IMC. However, the time duration that the molten pool was placed inside this temperature range was less than 1 s, and this duration was too short for diffusion-control based IMC growth.

Electrochemistry in a Nutshell: A General Chemistry Experiment.

ERIC Educational Resources Information Center

Baca, Glenn; Lewis, Dennis A.

1978-01-01

This experiment uses a nine-chambered plexiglas unit to facilitate rapid construction of galvanic cells and measurement of cell voltage. Using this procedure, a pair of students can construct and obtain the cell voltages of two precipitation cells, three concentration cells, and six redox cells in 30-40 minutes. (BB)

Soft x-ray-controlled dose deposition in yeast cells: techniques, model, and biological assessment

NASA Astrophysics Data System (ADS)

Milani, Marziale; Batani, Dimitri; Conti, Aldo; Masini, Alessandra; Costato, Michele; Pozzi, Achille; Turcu, I. C. Edmond

1996-12-01

A procedure is presented to release soft x-rays onto yeast cell membrane allegedly damaging the resident enzymatic processes connected with fermentation. The damage is expected to be restricted to regulating fermentation processes without interference with respiration. By this technique fermentation is followed leading to CO2 production, and respiration resulting in global pressure measurements. A solid state pressure sensor system has been developed linked to a data acquisition system. Yeast cells cultures have been investigated at different concentrations and with different nutrients. A non-monotone response in CO2 production as a function of the delivered x-ray dose is observed.

MINIMIZING DECOMPOSITION OF VAPORIZED HYDROGEN PEROXIDE IN CLEAN GALVANIZED STEEL DUCTING: IMPLICATIONS FOR BIOLOGICAL DECONTAMINATION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Verce, M F; Jayaraman, B; Ford, T D

2007-09-07

This work examined the behavior of vaporous hydrogen peroxide (VHP) in clean, room-scale galvanized steel (GS) and polyvinylchloride-coated steel air ducts, to understand how it might be used to decontaminate larger ventilation systems. VHP injected into the GS duct decreased in concentration along the length of the duct, whereas VHP concentrations in the polyvinylchloride coated duct remained essentially constant, suggesting that VHP decomposed at the GS surface. However, decomposition was reduced at lower temperatures ({approx} 22 C) and higher flow rates ({approx} 80 actual cubic meter per hour). A computational fluid dynamics model incorporating reactive transport was used to estimatemore » surface VHP concentrations where contamination is likely to reside, and also showed how bends encourage VHP decomposition. Use of G. stearothermophilus indicators, in conjunction with model estimates, indicated that a concentration-contact time of {approx} 100 mg/L H{sub 2}O{sub 2}(g){center_dot}min was required to achieve a 6 log reduction of indicator spores in clean GS duct, at 30 C. When VHP is selected for building decontamination, this work suggests the most efficacious strategy may be to decontaminate GS ducting separately from the rest of the building, as opposed to a single decontamination event in which the ventilation system is used to distribute VHP throughout the entire building.« less

Developing new optical imaging techniques for single particle and molecule tracking in live cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Wei

Differential interference contrast (DIC) microscopy is a far-field as well as wide-field optical imaging technique. Since it is non-invasive and requires no sample staining, DIC microscopy is suitable for tracking the motion of target molecules in live cells without interfering their functions. In addition, high numerical aperture objectives and condensers can be used in DIC microscopy. The depth of focus of DIC is shallow, which gives DIC much better optical sectioning ability than those of phase contrast and dark field microscopies. In this work, DIC was utilized to study dynamic biological processes including endocytosis and intracellular transport in live cells.more » The suitability of DIC microscopy for single particle tracking in live cells was first demonstrated by using DIC to monitor the entire endocytosis process of one mesoporous silica nanoparticle (MSN) into a live mammalian cell. By taking advantage of the optical sectioning ability of DIC, we recorded the depth profile of the MSN during the endocytosis process. The shape change around the nanoparticle due to the formation of a vesicle was also captured. DIC microscopy was further modified that the sample can be illuminated and imaged at two wavelengths simultaneously. By using the new technique, noble metal nanoparticles with different shapes and sizes were selectively imaged. Among all the examined metal nanoparticles, gold nanoparticles in rod shapes were found to be especially useful. Due to their anisotropic optical properties, gold nanorods showed as diffraction-limited spots with disproportionate bright and dark parts that are strongly dependent on their orientation in the 3D space. Gold nanorods were developed as orientation nanoprobes and were successfully used to report the self-rotation of gliding microtubules on kinesin coated substrates. Gold nanorods were further used to study the rotational motions of cargoes during the endocytosis and intracellular transport processes in live

Dependency of subcellular reactions during PDT on the metabolic state of cell cultures probed by different microscopic techniques

NASA Astrophysics Data System (ADS)

Rueck, Angelika C.; Schneckenburger, Herbert; Strauss, Wolfgang S. L.; Gschwend, Michael H.; Beck, Gerd C.; Kunzi-Rapp, Karin; Steiner, Rudolf W.

1994-02-01

Various microscopic techniques were used to study the dependency of photodynamically induced subcellular reactions on the metabolic state of cell cultures. TPPS4 and AlS2-3Pc were incubated in RR 1022 epithelial cells with varying cell density. To attain almost isolated cells (low cell density) or confluent growing cells (high cell density) 25 cells/mm2 or 500 cells/mm2 were seeded, respectively. Low cell density irradiation with blue light led to a change in the initial cytoplasmatic fluorescence pattern. For both sensitizers, TPPS4 as well as AlS2-3, a fluorescence relocalization and fluorescence intensity increase could be detected, moreover in the case of TPPS4 a fluorescence formation in the nucleus and nucleoli were detected. In contrast, for confluent growing cells no redistribution was observed.

Investigation of HIV-1 infected and uninfected cells using the optical trapping technique

NASA Astrophysics Data System (ADS)

Ombinda-Lemboumba, S.; Malabi, R.; Lugongolo, M. Y.; Thobakgale, S. L.; Manoto, S.; Mthunzi-Kufa, P.

2017-02-01

Optical trapping has emerged as an essential tool for manipulating single biological material and performing sophisticated spectroscopy analysis on individual cell. The optical trapping technique has been used to grab and immobilize cells from a tightly focused laser beam emitted through a high numerical aperture objective lens. Coupling optical trapping with other technologies is possible and allows stable sample trapping, while also facilitating molecular, chemical and spectroscopic analysis. For this reason, we are exploring laser trapping combined with laser spectroscopy as a potential non-invasive method of interrogating individual cells with a high degree of specificity in terms of information generated. Thus, for the delivery of as much pathological information as possible, we use a home-build optical trapping and spectroscopy system for real time probing human immunodeficiency virus (HIV-1) infected and uninfected single cells. Briefly, our experimental rig comprises an infrared continuous wave laser at 1064 nm with power output of 1.5 W, a 100X high numerical aperture oil-immersion microscope objective used to capture and immobilise individual cell samples as well as an excitation source. Spectroscopy spectral patterns obtained by the 1064 nm laser beam excitation provide information on HIV-1 infected and uninfected cells. We present these preliminary findings which may be valuable for the development of an HIV-1 point of care detection system.

Imaging interactions of metal oxide nanoparticles with macrophage cells by ultra-high resolution scanning electron microscopy techniques.

PubMed

Plascencia-Villa, Germán; Starr, Clarise R; Armstrong, Linda S; Ponce, Arturo; José-Yacamán, Miguel

2012-11-01

Use of engineered metal oxide nanoparticles in a plethora of biological applications and custom products has warned about some possible dose-dependent cytotoxic effects. Macrophages are key components of the innate immune system used to study possible toxic effects and internalization of different nanoparticulate materials. In this work, ultra-high resolution field emission scanning electron microscopy (FE-SEM) was used to offer new insights into the dynamical processes of interaction of nanomaterials with macrophage cells dosed with different concentrations of metal oxide nanoparticles (CeO(2), TiO(2) and ZnO). The versatility of FE-SEM has allowed obtaining a detailed characterization of processes of adsorption and endocytosis of nanoparticles, by using advanced analytical and imaging techniques on complete unstained uncoated cells, including secondary electron imaging, high-sensitive backscattered electron imaging, X-ray microanalysis and stereoimaging. Low voltage BF/DF-STEM confirmed nanoparticle adsorption and internalization into endosomes of CeO(2) and TiO(2), whereas ZnO develop apoptosis after 24 h of interaction caused by dissolution and invasion of cell nucleus. Ultra-high resolution scanning electron microscopy techniques provided new insights into interactions of inorganic nanoparticles with macrophage cells with high spatial resolution.

Inertial focusing and passive micro-mixing techniques for rare cells capturing microfluidic platform

NASA Astrophysics Data System (ADS)

Phadke, Manisha; Shaner, Sebastian; Shah, Shreyas; Rodriguez, Ygnacio; Wibowo, Denni; Whulanza, Yudan; Teriete, Peter; Allen, Jeff; Kassegne, Sam

2018-02-01

Isolation and capture of rare cells continues to be a daunting task that is still looking for an innovative and efficient method. While a variety of approaches have been suggested over the past several years, immunocapturing in a microfluidic platform carries a substantial promise as shown by recent published works. In this paper, we introduced a combination of inertial focusing and passive micro-mixing through 3D chevron-type features in a microchannel to induce chaotic mixing within antibody-coated microchannels and, ultimately, promote rare cell capture. The device introduced in this work contains curved microchannels that consist of a series of staggered chevron grooves. The curved channels enable inertial focusing while the chevron grooves allow for chaotic mixing. The microfluidics platform microfabricated through soft lithography has a polydimethylsiloxane (PDMS) foundation and was thinly coated with an alginate hydrogel derivatized with streptavidin. We submitted that our qualitative and quantitative results demonstrated the potentials in advancements in rare cell isolation through this integration of two techniques.

A new technique for reversible permeabilization of live cells for intracellular delivery of quantum dots

NASA Astrophysics Data System (ADS)

Medepalli, Krishnakiran; Alphenaar, Bruce W.; Keynton, Robert S.; Sethu, Palaniappan

2013-05-01

A major challenge with the use of quantum dots (QDs) for cellular imaging and biomolecular delivery is the attainment of QDs freely dispersed inside the cells. Conventional methods such as endocytosis, lipids based delivery and electroporation are associated with delivery of QDs in vesicles and/or as aggregates that are not monodispersed. In this study, we demonstrate a new technique for reversible permeabilization of cells to enable the introduction of freely dispersed QDs within the cytoplasm. Our approach combines osmosis driven fluid transport into cells achieved by creating a hypotonic environment and reversible permeabilization using low concentrations of cell permeabilization agents like Saponin. Our results confirm that highly efficient endocytosis-free intracellular delivery of QDs can be accomplished using this method. The best results were obtained when the cells were treated with 50 μg ml-1 Saponin in a hypotonic buffer at a 3:2 physiological buffer:DI water ratio for 5 min at 4 ° C.

Reliability evaluation of high-performance, low-power FinFET standard cells based on mixed RBB/FBB technique

NASA Astrophysics Data System (ADS)

Wang, Tian; Cui, Xiaoxin; Ni, Yewen; Liao, Kai; Liao, Nan; Yu, Dunshan; Cui, Xiaole

2017-04-01

With shrinking transistor feature size, the fin-type field-effect transistor (FinFET) has become the most promising option in low-power circuit design due to its superior capability to suppress leakage. To support the VLSI digital system flow based on logic synthesis, we have designed an optimized high-performance low-power FinFET standard cell library based on employing the mixed FBB/RBB technique in the existing stacked structure of each cell. This paper presents the reliability evaluation of the optimized cells under process and operating environment variations based on Monte Carlo analysis. The variations are modelled with Gaussian distribution of the device parameters and 10000 sweeps are conducted in the simulation to obtain the statistical properties of the worst-case delay and input-dependent leakage for each cell. For comparison, a set of non-optimal cells that adopt the same topology without employing the mixed biasing technique is also generated. Experimental results show that the optimized cells achieve standard deviation reduction of 39.1% and 30.7% at most in worst-case delay and input-dependent leakage respectively while the normalized deviation shrinking in worst-case delay and input-dependent leakage can be up to 98.37% and 24.13%, respectively, which demonstrates that our optimized cells are less sensitive to variability and exhibit more reliability. Project supported by the National Natural Science Foundation of China (No. 61306040), the State Key Development Program for Basic Research of China (No. 2015CB057201), the Beijing Natural Science Foundation (No. 4152020), and Natural Science Foundation of Guangdong Province, China (No. 2015A030313147).

Merkel Cell Carcinoma: An Update of Key Imaging Techniques, Prognostic Factors, Treatment, and Follow-up.

PubMed

Llombart, B; Kindem, S; Chust, M

2017-03-01

Merkel cell carcinoma, though rare, is one of the most aggressive tumors a dermatologist faces. More than a third of patients with this diagnosis die from the disease. Numerous researchers have attempted to identify clinical and pathologic predictors to guide prognosis, but their studies have produced inconsistent results. Because the incidence of Merkel cell carcinoma is low and it appears in patients of advanced age, prospective studies have not been done and no clear treatment algorithm has been developed. This review aims to provide an exhaustive, up-to-date account of Merkel cell carcinoma for the dermatologist. We describe prognostic factors and the imaging techniques that are most appropriate for evaluating disease spread. We also discuss current debates on treating Merkel cell carcinoma. Copyright © 2016 AEDV. Publicado por Elsevier España, S.L.U. All rights reserved.

An electrochemical investigation of TMJ implant metal alloys in an artificial joint fluid environment: the influence of pH variation.

PubMed

Royhman, Dmitry; Radhakrishnan, Rashmi; Yuan, Judy Chia-Chun; Mathew, Mathew T; Mercuri, Louis G; Sukotjo, Cortino

2014-10-01

To investigate the corrosion behaviour of commonly used TMJ implants alloys (CoCrMo and Ti6Al4V) under simulated physiological conditions. Corrosion behaviour was evaluated using standard electrochemical corrosion techniques and galvanic corrosion techniques as per ASTM standards. Standard electrochemical tests (E(corr), I(corr), R(p) and C(f)) were conducted in bovine calf serum (BCS), as a function of alloys type and different pHs. Galvanic corrosion tests were conducted in BCS at a pH of 7.6. Alloy surfaces were characterized using white-light interferometry (WLI) and scanning electron microscopy (SEM). The potentiodynamic test results exhibited the enhanced passive layer growth and a better corrosion resistance of Ti6Al4V compared to CoCrMo. Electrochemical impedance spectroscopy measurements demonstrated the influence of protein as a function of pH on corrosion mechanisms/kinetics. Galvanic coupling was not a major contributor to corrosion. SEM and WLI images demonstrated a significantly higher in surface roughness in CoCrMo after corrosion. The results of this study suggest that Ti6Al4V shows superior corrosion behaviour to CoCrMo due to its strong passive layer, simulated joint fluid components can affect the electrochemical nature of the metal/electrolyte interface as a function of pH, and the galvanic effect of coupling CoCrMo and Ti6Al4V in a single joint is weak. Published by Elsevier Ltd.

Real-time single cell analysis of molecular mechanism of apoptosis and proliferation using FRET technique

NASA Astrophysics Data System (ADS)

Chen, Tongsheng; Xing, Da; Gao, Xuejuan; Wang, Fang

2006-09-01

Bcl-2 family proteins (such as Bid and Bak/Bax) and 14-3-3 proteins play a key role in the mitochondria-mediated cell apoptosis induced by cell death factors such as TNF-α and lower power laser irradiation (LPLI). In this report, fluorescence resonance energy transfer (FRET) has been used to study the molecular mechanism of apoptosis in living cells on a fluorescence scanning confocal microscope. Based on the genetic code technique and the green fluorescent proteins (GFPs), single-cell dynamic analysis of caspase3 activation, caspase8 activation, and PKCs activation are performed during apoptosis induced by laser irradiation in real-time. To investigate the cellular effect and mechanism of laser irradiation, human lung adenocarcinoma cells (ASTC-a-1) transfected with plasmid SCAT3 (pSCAT3)/ CKAR FRET reporter, were irradiated and monitored noninvasively with both FRET imaging. Our results show that high fluence lower power laser irradiation (HFLPLI) can induce an increase of caspase3 activation and a decrease of PKCs activation, and that LPLI induces the ASTC-a-1 cell proliferation by specifically activating PKCs.

Spatial and temporal single-cell volume estimation by a fluorescence imaging technique with application to astrocytes in primary culture

NASA Astrophysics Data System (ADS)

Khatibi, Siamak; Allansson, Louise; Gustavsson, Tomas; Blomstrand, Fredrik; Hansson, Elisabeth; Olsson, Torsten

1999-05-01

Cell volume changes are often associated with important physiological and pathological processes in the cell. These changes may be the means by which the cell interacts with its surrounding. Astroglial cells change their volume and shape under several circumstances that affect the central nervous system. Following an incidence of brain damage, such as a stroke or a traumatic brain injury, one of the first events seen is swelling of the astroglial cells. In order to study this and other similar phenomena, it is desirable to develop technical instrumentation and analysis methods capable of detecting and characterizing dynamic cell shape changes in a quantitative and robust way. We have developed a technique to monitor and to quantify the spatial and temporal volume changes in a single cell in primary culture. The technique is based on two- and three-dimensional fluorescence imaging. The temporal information is obtained from a sequence of microscope images, which are analyzed in real time. The spatial data is collected in a sequence of images from the microscope, which is automatically focused up and down through the specimen. The analysis of spatial data is performed off-line and consists of photobleaching compensation, focus restoration, filtering, segmentation and spatial volume estimation.

Circulating tumor cell isolation during resection of colorectal cancer lung and liver metastases: a prospective trial with different detection techniques.

PubMed

Kaifi, Jussuf T; Kunkel, Miriam; Das, Avisnata; Harouaka, Ramdane A; Dicker, David T; Li, Guangfu; Zhu, Junjia; Clawson, Gary A; Yang, Zhaohai; Reed, Michael F; Gusani, Niraj J; Kimchi, Eric T; Staveley-O'Carroll, Kevin F; Zheng, Si-Yang; El-Deiry, Wafik S

2015-01-01

Colorectal cancer (CRC) metastasectomy improves survival, however most patient develop recurrences. Circulating tumor cells (CTCs) are an independent prognostic marker in stage IV CRC. We hypothesized that CTCs can be enriched during metastasectomy applying different isolation techniques. 25 CRC patients undergoing liver (16 (64%)) or lung (9 (36%)) metastasectomy were prospectively enrolled (clinicaltrial.gov identifier: NCT01722903). Central venous (liver) or radial artery (lung) tumor outflow blood (7.5 ml) was collected at incision, during resection, 30 min after resection, and on postoperative day (POD) 1. CTCs were quantified with 1. EpCAM-based CellSearch® system and 2. size-based isolation with a novel filter device (FMSA). CTCs were immunohistochemically identified using CellSearch®'s criteria (cytokeratin 8/18/19+, CD45- cells containing a nucleus (DAPI+)). CTCs were also enriched with a centrifugation technique (OncoQuick®). CTC numbers peaked during the resection with the FMSA in contrast to CellSearch® (mean CTC number during resection: FMSA: 22.56 (SEM 7.48) (p = 0.0281), CellSearch®: 0.87 (SEM ± 0.44) (p = 0.3018)). Comparing the 2 techniques, CTC quantity was significantly higher with the FMSA device (range 0-101) than CellSearch® (range 0-9) at each of the 4 time points examined (P < 0.05). Immunofluorescence staining of cultured CTCs revealed that CTCs have a combined epithelial (CK8/18/19) and macrophage (CD45/CD14) phenotype. Blood sampling during CRC metastasis resection is an opportunity to increase CTC capture efficiency. CTC isolation with the FMSA yields more CTCs than the CellSearch® system. Future studies should focus on characterization of single CTCs to identify targets for molecular therapy and immune escape mechanisms of cancer cells.

Microscopy techniques in flavivirus research.

PubMed

Chong, Mun Keat; Chua, Anthony Jin Shun; Tan, Terence Tze Tong; Tan, Suat Hoon; Ng, Mah Lee

2014-04-01

The Flavivirus genus is composed of many medically important viruses that cause high morbidity and mortality, which include Dengue and West Nile viruses. Various molecular and biochemical techniques have been developed in the endeavour to study flaviviruses. However, microscopy techniques still have irreplaceable roles in the identification of novel virus pathogens and characterization of morphological changes in virus-infected cells. Fluorescence microscopy contributes greatly in understanding the fundamental viral protein localizations and virus-host protein interactions during infection. Electron microscopy remains the gold standard for visualizing ultra-structural features of virus particles and infected cells. New imaging techniques and combinatory applications are continuously being developed to push the limit of resolution and extract more quantitative data. Currently, correlative live cell imaging and high resolution three-dimensional imaging have already been achieved through the tandem use of optical and electron microscopy in analyzing biological specimens. Microscopy techniques are also used to measure protein binding affinities and determine the mobility pattern of proteins in cells. This chapter will consolidate on the applications of various well-established microscopy techniques in flavivirus research, and discuss how recently developed microscopy techniques can potentially help advance our understanding in these membrane viruses. Copyright © 2013 Elsevier Ltd. All rights reserved.

Application of the MOS-C-V technique to determine impurity concentrations and surface parameters on the diffused face of silicon solar cells

NASA Technical Reports Server (NTRS)

Weinberg, I.

1975-01-01

The feasibility of using the MOS C-V technique to obtain information regarding impurity and surface state concentrations on the diffused face of silicon solar cells with Ta2O5 coatings is studied. Results indicate that the MOS C-V technique yields useful information concerning surface parameters which contribute to the high, efficiency limiting, surface recombination velocities on the n+ surface of silicon solar cells.

Application of X-ray and neutron small angle scattering techniques to study the hierarchical structure of plant cell walls: a review.

PubMed

Martínez-Sanz, Marta; Gidley, Michael J; Gilbert, Elliot P

2015-07-10

Plant cell walls present an extremely complex structure of hierarchically assembled cellulose microfibrils embedded in a multi-component matrix. The biosynthesis process determines the mechanism of cellulose crystallisation and assembly, as well as the interaction of cellulose with other cell wall components. Thus, a knowledge of cellulose microfibril and bundle architecture, and the structural role of matrix components, is crucial for understanding cell wall functional and technological roles. Small angle scattering techniques, combined with complementary methods, provide an efficient approach to characterise plant cell walls, covering a broad and relevant size range while minimising experimental artefacts derived from sample treatment. Given the system complexity, approaches such as component extraction and the use of plant cell wall analogues are typically employed to enable the interpretation of experimental results. This review summarises the current research status on the characterisation of the hierarchical structure of plant cell walls using small angle scattering techniques. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

Interferometric and nonlinear-optical spectral-imaging techniques for outer space and live cells

NASA Astrophysics Data System (ADS)

Itoh, Kazuyoshi

2015-12-01

Multidimensional signals such as the spectral images allow us to have deeper insights into the natures of objects. In this paper the spectral imaging techniques that are based on optical interferometry and nonlinear optics are presented. The interferometric imaging technique is based on the unified theory of Van Cittert-Zernike and Wiener-Khintchine theorems and allows us to retrieve a spectral image of an object in the far zone from the 3D spatial coherence function. The retrieval principle is explained using a very simple object. The promising applications to space interferometers for astronomy that are currently in progress will also be briefly touched on. An interesting extension of interferometric spectral imaging is a 3D and spectral imaging technique that records 4D information of objects where the 3D and spectral information is retrieved from the cross-spectral density function of optical field. The 3D imaging is realized via the numerical inverse propagation of the cross-spectral density. A few techniques suggested recently are introduced. The nonlinear optical technique that utilizes stimulated Raman scattering (SRS) for spectral imaging of biomedical targets is presented lastly. The strong signals of SRS permit us to get vibrational information of molecules in the live cell or tissue in real time. The vibrational information of unstained or unlabeled molecules is crucial especially for medical applications. The 3D information due to the optical nonlinearity is also the attractive feature of SRS spectral microscopy.

The Corrosion Protection of 2219-T87 Aluminum by Organic and Inorganic Zinc-Rich Primers

NASA Technical Reports Server (NTRS)

Danford, M. D.; Mendrek, M. J.; Walsh, D. W.

1995-01-01

The behavior of zinc-rich primer-coated 2219-T87 aluminum in a 3.5-percent Na-Cl was investigated using electrochemical techniques. The alternating current (ac) method of electrochemical impedance spectroscopy (EIS), in the frequency range of 0.001 to 40,000 Hz, and the direct current (dc) method of polarization resistance (PR) were used to evaluate the characteristics of an organic, epoxy zinc-rich primer and an inorganic, ethyl silicate zinc-rich primer. A dc electrochemical galvanic corrosion test was also used to determine the corrosion current of each zinc-rich primer anode coupled to a 2219-T87 aluminum cathode. Duration of the EIS/PR and galvanic testing was 21 days and 24 h, respectively. The galvanic test results demonstrated a very high galvanic current between the aluminum cathode and both zinc-rich primer anodes (37.9 pA/CM2 and 23.7 pA/CM2 for the organic and inorganic primers, respectively). The PR results demonstrated a much higher corrosion rate of the zinc in the inorganic primer than in the organic primer, due primarily to the higher porosity in the former. Based on this investigation, the inorganic zinc-rich primer appears to provide superior galvanic protection and is recommended for additional study for application in the solid rocket booster aft skirt.

The corrosion protection of 2219-T87 aluminum by organic and inorganic zinc-rich primers

NASA Technical Reports Server (NTRS)

Danford, M. D.; Mendrek, M. J.; Walsh, D. W.

1995-01-01

The behavior of zinc-rich primer-coated 2219-T87 aluminum in a 3.5-percent Na-Cl was investigated using electrochemical techniques. The alternating current (ac) method of electro-chemical impedance spectroscopy (EIS), in the frequency range of 0.001 to 40,000 Hz, and the direct current (dc) method of polarization resistance (PR) were used to evaluate the characteristics of an organic, epoxy zinc-rich primer and an inorganic, ethyl silicate zinc-rich primer. A dc electrochemical galvanic corrosion test was also used to determine the corrosion current of each zinc-rich primer anode coupled to a 2219-T87 aluminum cathode. Duration of the EIS/PR and galvanic testing was 21 days and 24 h, respectively. the galvanic test results demonstrated a very high galvanic current between the aluminum cathode and both zinc-rich primer anodes (37.9 micro A/cm(exp 2) and 23.7 micro A/cm(exp 2) for the organic and inorganic primers, respectively). The PR results demonstrated a much higher corrosion rate of the zinc in the inorganic primer than in the organic primer, due primarily to the higher porosity in the former. Based on this investigation, the inorganic zinc-rich primer appears to provide superior galvanic protection and is recommended for additional study for application in the solid rocket booster aft skirt.

Modeling for intra-body communication with bone effect.

PubMed

Pun, S H; Gao, Y M; Mak, P U; Du, M; Vai, M I

2009-01-01

Intra-body communication (IBC) is a new, different "wireless" communication technique based on the human tissue. This short range "wireless" communication technology provides an alternative solution to wearable sensors, home health system, telemedicine and implanted devices. The development of the IBC enables the possibilities of providing less complexity and convenient communication methodologies for these devices. By regarding human tissue as communication channel, IBC making use of the conductivities properties of human tissue to send electrical signal from transmitter to receiver. In this paper, the authors proposed a new mathematical model for galvanic coupling type IBC based on a human limb. Starting from the electromagnetic theory, the authors treat human tissue as volume conductor, which is in analogous with the bioelectric phenomena analysis. In order to explain the mechanism of galvanic coupling type technique of IBC, applying the quasi-static approximation, the governing equation can be reduced to Laplace Equation. Finally, the analytical model is evaluated with on-body measurement for testing its performance. The comparison result shows that the developed mathematical model can provide good approximation for galvanic coupling type IBC on human limb under low operating frequencies.

Cross Coating Weight Control by Electromagnetic Strip Stabilization at the Continuous Galvanizing Line of ArcelorMittal Florange

NASA Astrophysics Data System (ADS)

Guelton, Nicolas; Lopès, Catherine; Sordini, Henri

2016-08-01

In hot dip galvanizing lines, strip bending around the sink roll generates a flatness defect called crossbow. This defect affects the cross coating weight distribution by changing the knife-to-strip distance along the strip width and requires a significant increase in coating target to prevent any risk of undercoating. The already-existing coating weight control system succeeds in eliminating both average and skew coating errors but cannot do anything against crossbow coating errors. It has therefore been upgraded with a flatness correction function which takes advantage of the possibility of controlling the electromagnetic stabilizer. The basic principle is to split, for every gage scan, the coating weight cross profile of the top and bottom sides into two, respectively, linear and non-linear components. The linear component is used to correct the skew error by realigning the knives with the strip, while the non-linear component is used to distort the strip in the stabilizer in such a way that the strip is kept flat between the knives. Industrial evaluation is currently in progress but the first results have already shown that the strip can be significantly flattened between the knives and the production tolerances subsequently tightened without compromising quality.

The lesion site of vestibular dysfunction in Ramsay Hunt syndrome: a study by click and galvanic VEMP.

PubMed

Ozeki, Hidenori; Iwasaki, Shinichi; Ushio, Munetaka; Takeuchi, Naonobu; Murofushi, Toshihisa

2006-01-01

Ramsay Hunt syndrome (RHS) is characterized by vestibulocochlear dysfunction in addition to facial paralysis and auricular vesicles. The present study investigated the lesion site of vestibular dysfunction in a group of 10 RHS patients. Caloric testing, vestibular evoked myogenic potentials by click sound (cVEMP) and by galvanic stimulation (gVEMP) were used to assess the function of the lateral semicircular canal, saccule, and their afferents. The results of caloric testing (all 10 cases showed canal paresis) mean the existence of lesion sites in lateral semicircular canal and/or superior vestibular nerve (SVN). Abnormal cVEMPs in 7 patients mean the existence of lesions in saccule and/or inferior vestibular nerve (IVN). Four of the 6 patients with absent cVEMP also underwent gVEMP. The results of gVEMP (2 absent and 2 normal) mean that the former 2 have lesions of the vestibular nerve, and the latter 2 have only saccular lesions concerning the pathway of VEMPs. Thus, our study suggested that lesion sites of vestibular symptoms in RHS could be in the vestibular nerve and/or labyrinth, and in SVN and/or IVN. In other words, in the light of vestibular symptoms, there is the diversity of lesion sites.

A study of the influence of air-knife tilting on coating thickness in hot-dip galvanizing

NASA Astrophysics Data System (ADS)