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Test Cells (test + cell)

Distribution by Scientific Domains

Polymers and Materials Science	18%
Medical Sciences	18%
Life Sciences	18%

Selected Abstracts

Effects of moisture content, impulse polarity and earth electrode's dimension on dry and wet sand under high voltage conditions

EUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 5 2008
N. Mohamad Nor
Abstract The study on the physics of discharges in soil and performance of earthing networks subjected to lightning currents are important in order to improve the reliability of electrical systems and to obtain better electrical models of earthing systems. The soil characteristics of various moisture contents under high-impulse currents have been well studied in previous studies. In this present study, fast impulse generator is used to investigate the dry soil characteristics in two cylindrical test cells of different outer radii; 15 and 20,cm under high magnitude fast impulse conditions of both impulse polarities. This allows to study the characteristics of dry soil under high-impulse current conditions, and allows a comparison between the dry and wet soil characteristics under high-impulse conditions such as before and after breakdown of the test cell. In this study, the effects of impulse polarities, moisture content in soil and the outer dimensions of test cell on the soil characteristics under high-impulse currents were investigated. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Analysis of cake filtration data,A critical assessment of conventional filtration theory

AICHE JOURNAL, Issue 10 2006
Soo-Khean Teoh
Abstract Experimental results of constant-pressure cake filtration of aqueous suspensions of four kinds of particles: CaCO3, Kaolin, Kromasil and TiO2 is presented. The data reported consist mainly of filtration performance results, that is, the cumulative filtrate volume and cake thickness as functions of time, which were obtained using a newly developed multifunction test cell. Based on these data, the medium resistance and the average cake specific resistance at various operating pressure were evaluated and corroborated with the results obtained from the compression-permeability (C-P) cell measurements. The filtration results were also compared with predictions from the solutions of the appropriate volume-averaged equations of continuity using different pl , ps relationships. Generally speaking, with the appropriate pl , ps relationship, agreement between experiments and prediction was satisfactory. © 2006 American Institute of Chemical Engineers AIChE J, 2006 [source]

Testing a cumulus parametrization with a cumulus ensemble model in weak-temperature-gradient mode

THE QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Issue 626 2007
D. J. Raymond
Abstract This paper prototypes a method for calibrating a cumulus parametrization against a cumulus ensemble model. The key to this technique is to run the cumulus model and the parametrization in identical ,test cells' that provide forcing typical of that seen over tropical oceans. In particular, the mean temperature profile is relaxed to a reference profile that is assumed to be characteristic of the environment of the convection. This is done by calculating the mean vertical velocity needed to balance heating due to convection, latent-heat release, and radiation with adiabatic cooling. This ,weak-temperature-gradient' vertical-velocity profile is then used to advect moisture vertically and, via mass continuity, through the sides of the test cell, entraining reference-profile air as needed. As an example, a toy cumulus parametrization used previously is altered to reproduce the dependence of rainfall rate on surface wind speed shown by the cumulus ensemble model. This alteration greatly changes the behaviour of simulated large-scale disturbances in an aquaplanet equatorial beta-plane model. In particular, increasing the slope of the curve of rainfall rate against wind speed results in the development of much greater synoptic-scale variance. Copyright © 2007 Royal Meteorological Society [source]

Molecular cloning and sequence analysis of an ascidian egg ,-N-acetylhexosaminidase with a potential role in fertilization

DEVELOPMENT GROWTH & DIFFERENTIATION, Issue 3 2003
Ryo Koyanagi
,-N-Acetylhexosaminidase, which is found almost ubiquitously in sperm of invertebrates and vertebrates, supposedly mediates a carbohydrate-based transient sperm,egg coat binding. In ascidians and mammals, ,-hexosaminidase released at fertilization from eggs has been proposed to modify sperm receptor glycoproteins of the egg envelope, thus setting up a block to polyspermy. Previously, it was shown that in potential sperm receptor glycoproteins of the ascidian Phallusia mammillata, N-acetylglucosamine is the prevailing glycoside residue and that the egg harbors three active molecular forms of ,-hexosaminidase. In the present study, P. mammillata,-hexosaminidase cDNA was isolated from an ovarian cDNA library and characterized. The deduced amino acid sequence showed a high similarity with other known ,-hexosaminidases; however, P. mammillata,-hexosaminidase had a unique potential N-glycosylation site. A phylogenetic analysis suggested that P. mammillata,-hexosaminidase developed independently after having branched off from the common ancestor gene of the chordate enzyme before two isoforms of the mammalian enzyme appeared. In situ hybridization revealed stage-specific expression of ,-hexosaminidase mRNA during oogenesis in the oocyte and in the accessory test and follicle cells. This suggests that the three egg ,-hexosaminidase forms are specific for the oocyte, test cells and follicle cells. [source]

Effects of moisture content, impulse polarity and earth electrode's dimension on dry and wet sand under high voltage conditions

Efficiency Enhancement in Organic Photovoltaic Cells: Consequences of Optimizing Series Resistance

ADVANCED FUNCTIONAL MATERIALS, Issue 1 2010
Jonathan D. Servaites
Abstract Here, means to enhance power conversion efficiency (PCE or ,) in bulk-heterojunction (BHJ) organic photovoltaic (OPV) cells by optimizing the series resistance (Rs),also known as the cell internal resistance,are studied. It is shown that current state-of-the-art BHJ OPVs are approaching the limit for which efficiency can be improved via Rs reduction alone. This evaluation addresses OPVs based on a poly(3-hexylthiophene):6,6-phenyl C61 -butyric acid methyl ester (P3HT:PCBM) active layer, as well as future high-efficiency OPVs (,,>,10%). A diode-based modeling approach is used to assess changes in Rs. Given that typical published P3HT:PCBM test cells have relatively small areas (,0.1,cm2), the analysis is extended to consider efficiency losses for larger area cells and shows that the transparent anode conductivity is then the dominant materials parameter affecting Rs efficiency losses. A model is developed that uses cell sizes and anode conductivities to predict current,voltage response as a function of resistive losses. The results show that the losses due to Rs remain minimal until relatively large cell areas (>0.1,cm2) are employed. Finally, Rs effects on a projected high-efficiency OPV scenario are assessed, based on the goal of cell efficiencies >10%. Here, Rs optimization effects remain modest; however, there are now more pronounced losses due to cell size, and it is shown how these losses can be mitigated by using higher conductivity anodes. [source]

Encapsulated-Dye All-Organic Charged Colored Ink Nanoparticles for Electrophoretic Image Display

ADVANCED MATERIALS, Issue 48 2009
Sun Wha Oh
Electrophoretic ink nanoparticles with high mobility are successfully fabricated by dispersion polymerization. The color of test cells can be changed by applying a bias voltage, as shown in the figure: the lower row shows the same cells as the upper row but with an applied voltage. These all-organic, encapsulated-dye, electrophoretic ink particles are expected to reduce the fabrication cost of e-ink in electrophoretic image display cells. [source]

Role of enzyme-treated cells in RBC antibody screening using the gel test: a study of anti-RH1, -RH2, and -RH3 antibodies

JOURNAL OF CLINICAL LABORATORY ANALYSIS, Issue 2 2007
Jocelyne Conne
Abstract The role of enzyme-treated cells (ETCs) in red blood cell (RBC) antibody screening has been the subject of controversy, and its place in the clinical routine remains to be determined. In this work, plasma samples containing anti-RH1 (anti-D; N = 10), anti-RH2 (anti-C; N = 10), or anti-RH3 (anti-E; N = 10) antibodies were studied. The samples were diluted in nonbuffered or buffered normal saline, as well as in a pool of AB plasma samples. Titers and scores were determined by means of the gel test, using the indirect antiglobulin test (IAT) as well as ETCs, with R0r, r,r, or r,r test cells. Our results showed that compared to the IAT, ETCs allowed a clearer detection of anti-RH2 and anti-RH3, but not of anti-RH1 antibodies. Based on our study, it is not clear whether the ETC phase of the gel test should be maintained for RBC antibody screening. J. Clin. Lab. Anal. 21:61,66, 2007. © 2007 Wiley-Liss, Inc. [source]

Solubilization of the lichen metabolite (+)-usnic acid for testing in tissue culture

JOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 11 2002
Thórdís Kristmundsdóttir
The pharmacological testing of natural products can often be hampered by the poor solubility of such compounds in non-toxic solvents. There is thus a need for a suitable agent for solubilization of natural substances to allow testing on a variety of cell lines in-vitro. Such an agent should ideally have no direct effects on any of the commonly used cell lines from a variety of tissues and mammalian species to allow proper comparison. In this study, the lichen metabolite (+)-usnic acid, a dibenzofuran derivative, was used as a prototype for an insoluble natural product with the aim of finding a solvent that was both capable of solubilizing usnic acid and was free of direct activity against a test cell line. Solubilization was measured at different pH values in various concentrations of co-solvents (glycofurol 75, propylene glycol, polyethylene glycol 400), surfactants (polysorbate 20 and Cremophor RH40), and the complexing agent 2-hydroxypropyl-,-cyclodextrin. The solubility achieved in a 20% aqueous solution was 0.11 mg mL,1 for propylene glycol, 0.19 for PEG 400, 0.27 for glycofurol 75, 0.57 for Cremophor RH40, 0.68 for 2-hydroxypropyl-,-cyclodextrin and 0.84 for polysorbate 20. The direct effects of the various solvent systems were tested on the human leukaemia cell line K-562 in a standard proliferation assay. Most of the solvents proved toxic with the exception of propylene glycol, PEG 400 and 2-hydroxypropyl-,-cyclodextrin. Anti-proliferative activity of usnic acid could be demonstrated with an ED50 (amount of substance required to reduce thymidine uptake to 50% of uptake by untreated control culture) of 4.7,g mL,1 using PEG 400 and 2-hydroxypropyl-,-cyclodextrin but only the latter gave satisfactory solubility. 2-Hydroxypropyl-,-cyclodextrin was thus identified as a solubilizing agent that fulfilled both set criteria of solubility and lack of toxicity against the test cells. [source]

DATE analysis: A general theory of biological change applied to microarray data

BIOTECHNOLOGY PROGRESS, Issue 5 2009
David Rasnick
Abstract In contrast to conventional data mining, which searches for specific subsets of genes (extensive variables) to correlate with specific phenotypes, DATE analysis correlates intensive state variables calculated from the same datasets. At the heart of DATE analysis are two biological equations of state not dependent on genetic pathways. This result distinguishes DATE analysis from other bioinformatics approaches. The dimensionless state variable F quantifies the relative overall cellular activity of test cells compared to well-chosen reference cells. The variable ,i is the fold-change in the expression of the ith gene of test cells relative to reference. It is the fraction , of the genome undergoing differential expression,not the magnitude ,,that controls biological change. The state variable , is equivalent to the control strength of metabolic control analysis. For tractability, DATE analysis assumes a linear system of enzyme-connected networks and exploits the small average contribution of each cellular component. This approach was validated by reproducible values of the state variables F, RNA index, and , calculated from random subsets of transcript microarray data. Using published microarray data, F, RNA index, and , were correlated with: (1) the blood-feeding cycle of the malaria parasite, (2) embryonic development of the fruit fly, (3) temperature adaptation of Killifish, (4) exponential growth of cultured S. pneumoniae, and (5) human cancers. DATE analysis was applied to aCGH data from the great apes. A good example of the power of DATE analysis is its application to genomically unstable cancers, which have been refractory to data mining strategies. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 [source]