Cell properties

Pericytes are mural cells which stabilise capillaries and control functions of capillary endothelial cell properties. 

Madan et al. [515] have presented the effect of modulation on the properties of the material (dark conductivity and photoconductivity) and of solar cells. They also observe an increase in deposition rate as a function of modulation frequency (up to 100 kHz) at an excitation frequency of 13.56 MHz, in their PECVD system [159]. The optimum modulation frequency was 68 kHz, which they attribute to constraints in the matching networks. Increasing the deposition rate in cw operation of the plasma by increasing the RF power leads to worse material. Modulation with a frequency larger than 60 kHz results in improved material quality, for material deposited with equal deposition rates. This is also seen in the solar cell properties. The intrinsic a-Si H produced by RF modulation was included in standard p-i-n solar cells, without buffer or graded interface layers. For comparison, solar cells employing layers that were deposited under cw conditions were also made. At a low deposition rate of about 0.2 nm/s, the cw solar cell parameters... 

Illumination of solar cells causes a reduction of efficiency and fill factor, as a result of light-induced creation of defects (Staebler-Wronski effect. Section 1.1.2.5). This reduction is halted after several hundred hours of illumination. The reduction is correlated with solar cell thickness. A large intrinsic layer thickness leads to a large reduction of efficiency and fill factor compared to a small intrinsic layer thickness. The solar cell properties can be completely recovered by annealing at about 150°C. The open circuit voltage and short circuit current decrease only slightly. 

Environmental factors control lineage decisions of neural crest cells. Several experimental approaches have shown that environmental factors are critical in determining neurotransmitter phenotype by altering existing cell properties and not by selecting different hypothetical subpopulations of NC cells. For example, during normal... 

Calu-3 (American type culture collection ATCC HTB-55) is a human bronchial epithelial cell line derived from an adenocarcinoma of the lung [59], This cell line has been shown to exhibit serous cell properties and form confluent monolayers of mixed cell phenotypes, including ciliated and secretory cell types [60], but the cilia are formed very irregularly and seem to disappear with increasing passage number (unpublished observations, C.E. and B.F.). Calu-3 cells have shown utility as a model to examine transport [61-63] and metabolism in human bronchial epithelial cells for many therapeutic compounds [64], Furthermore, they have been used in a number of particlecell interaction studies [65-67], The interactions between respiratory epithelial cells and particulates are discussed more in detail in Chap. 19. 

Ponti D, Costa A, Zaffaroni N et al (2005) Isolation and in vitro propagation of tumorigenic breast cancer cells with stem/progenitor cell properties. Cancer Res 65 5506-5511... 

A galvanostatic perturbation, in principle, can be applied by means of a rather simple electrical circuit, as is represented in Fig. 3(a). (More sophisticated instrumentation, employing operational amplifiers, has been described in the literature see ref. 22). It is only required that the galvanostat resistance, Rg, be large compared with the equivalent cell resistance, so that the current forced through the cell is independent of the cell properties. If the source of electricity is a d.c. source, as in Fig. 3(a), a constant current I — jA will start to flow after the time t = 0 at which the circuit is closed [see Fig. 3(b)]. The effect of this action will... 

As can be seen in Fig. 5.33, not all unit cells are cubic. Other types of unit cells have different restrictions placed on the lattice parameters (edge lengths and angles). Unit cell properties such as cell... 

The micro-tubular SOFCs considered are depicted in Figure 4.19. Specifically, Figure 4.19 shows the anode (supporting structure), the anode plus the electrolyte, and the final single cells. More details about the production process, the cell properties and characteristics can be found in [13-15],... 

A necessary prerequisite for high module efficiencies is the uniform distribution of material and cell properties on the substrate to avoid power losses due to averaging effects. The total area of solar modules is divided into cell strips, which are interconnected by a sequence of deposition and cutting steps. Figure 8.11 illustrates the structure for series-connection in thin film silicon... 

Flow cytometry is a very versatile technique [223] which allows the analysis of more than 104 cells per second [369,370]. This high number results in statistically significant data and distributions of cell properties. Therefore, flow cytometry is a key technique to segregate biomass (into distinct cell classes) and to study microbial populations and their dynamics, specifically the cell cycle [76, 87, 116, 200, 214, 221, 295, 329, 330, 409, 418]. Individual cells are aligned by means of controlled hydrodynamic flow patterns and pass the measuring cell one by one. One or more light sources, typically laser(s), are focused onto the stream of cells and a detection unit(s) measure(s) the scattered and/or fluorescent light (Fig. 24). Properties of whole cells such as size and shape can be... 

The most direct way to carry out the measurements is in places where the measured solar spectrum is found to be nearly identical to the standard AM1.5G spectrum. By measuring the temperature dependence and irradi-ance dependence of the I/V curve parameters, cell properties may be adjusted to the SRC. Since in most places around the world these SRC conditions cannot be met, characterisation laboratories have been set up with suitable apparatus and procedures to do accurate indoor efficiency measurements under SRC according to international standard norms (ASTM, IEC). This involves... 

When we begin to investigate an electrochemical system, we normally know little about the processes or mechanisms within the system. Electrochemical impedance spectroscopy (EIS) can be a powerful approach to help us establish a hypothesis using equivalent circuit models. A data-fitted equivalent circuit model will suggest valuable chemical processes or mechanisms for the electrochemical system being studied. From Chapter 1, we know that a fuel cell is actually an electrochemical system involving electrode/electrolyte interfaces, electrode reactions, as well as mass transfer processes. Therefore, EIS can also be a powerful tool to diagnose fuel cell properties and performance. 

Although EIS offers many advantages for diagnosing fuel cell properties, clear difficulties exist for applying impedance methods and fitting the data to the model to extract the relevant electrochemical parameters. The limitations of the EIS technique derive from the several requirements required to obtain a valid impedance spectrum, because the accuracy of EIS measurement depends not only on the technical precision of the instrumentation but also on the operating procedures. Theoretically, there are three basic requirements for AC impedance measurements linearity, stability, and causality. 

Ashby s theoretical studies of the mechanical behavior of cellular solids, and those of his followers as well, serve as most useful guidelines. But one should always keep in mind that cellular foods do not have cells of rmiform size and geometry. Closed and open cells can coexist at different ratios and the former can sometimes burst open upon compression, as has been demonstrated in breads. In the future, nondestructive imaging methods to determine 3-D structures will probably provide information that will clarify the relationship between the cellular architecture, the cells properties and texture. 

Hickner, M.A. and Pivovar, B.S., The chemical and structural nature of proton exchange membrane fuel cell properties. Fuel Cells, 5, 213, 2005. 

Passive deformability. Two methods were devised to measure cell properties that are related to their deformability. The micropipette aspiration method (Sato and Suzuki, 1976) consists in measuring the negative pressure required for a cell or a portion thereof to enter a pipet the opening of which is smaller than the diameter of the cell. This method is laborious and requires a skilled operator. Cells have to be measured one at a time, and since cell and capillary diameters must have a constant ratio, the sampling of a population is time consuming and requires a set of different pipettes. As a consequence, this method is not widely used, and will not be further described. 

Moisture absorptfon of plastic foams is closely connected with cell properties, including thermal insulation properties. Investigation of heat insulation of plastic foams containing a liquid phase helps to elucidate the mechanisms of moisture and mass transfer as weU as of heat transfer in gas-filled materials. 

At present there is still a lack of well characterized and well differentiated cell lines of human origin representative of the different cell-types present in the nephron and the collecting duct system. However, once available, human immortahzed cell tines of defined nephron segment origin will likely provide a welcome alternative to primary cultures for studying cell properties in vitro in a cell-type dependent way. 

Ph. Mandin, A. Ait Aissa, H. Roustan, J. Hamburger, G. Picard, Two-phase electrolysis process from the bubble to the electrochemical cell properties, Chemical Engineering and Processing Process intensification, 47 (2008) ppl926-1932... 

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