Radiation cell models

Radiation-induced genomic instability and bystander effects are now well-established consequences of exposure of living cells to ionizing radiation. Cells not directly traversed by radiation may still exhibit radiation effects. This phenomenon, known as bystander effect, has become a major activity in radiation biology and in some cases has challenged the conventional wisdom. An example is the currently accepted models used for low-dose extrapolation of radiation risks. The currently used models assume that cells in an irradiated population respond individually rather than collectively. If bystander effects have implications for health risks estimates from exposure to ionizing radiation, then the question of whether this is a general phenomenon or solely a characteristic of a particular type of cell and the radiation under test becomes an important issue. 

VanderSteen J.D.J., Pharoah J.G. (2004) The effect of radiation heat transfer in solid oxide fuel cells modeling. Combustion Institute/Canadian Section, Spring Technical Meeting, Queen s University, May 9-12, 2004. 

Elnashaie and Cresswell (1974b) investigated the influence of the mass capacity of the pellet on the reactor dynamics using a cell model and assumed that heat transport within the bed takes place through radiation. 

In reactors which operate at very high temperatures, radiation of heat from one particle to the other may be important. With exothermic reactions, the reaction tends to take place in a narrow zone with a very large temperature increase over a very short length. Transport of heat by radiation must then be considered and this is most easily done by a cell model. Due to this coupling a straightforward marching technique for computation is not possible. 

The diffuse reflectance accessory (model DRA-2CN, Harrick Scientific) was modified with a three-dimensional translational stage to optimally position the sample for maximum radiation throughput (15). The sample cell (model HVC-DRP, Harrick Scientific) was heated by a resistive heater contained within a post that housed a sample cup. The base of the sample cell also contained an external connector for evacuation and a second port, which was sealed with a septum and used for the introduction of pyridine by microsyringe. The sample cell cover contained a channel and connectors for water cooling and ZnSe windows (12 mm in diameter) for the IR radiation. The base and cover of the cell were sealed vacuum-right with an O-ring. 

Fig. 1. The two cell model includes solar radiation (l-a)F, blackbody radiation from the surface A+BT, longwave atmospheric radiation P(A+BT), and horizontal advection D. The longwave radiation from the atmosphere to space does not figure into the model.

Beta radiation Electron emission from unstable nuclei, 26,30,528 Binary molecular compound, 41-42,190 Binding energy Energy equivalent of the mass defect measure of nuclear stability, 522,523 Bismuth (m) sulfide, 540 Blassie, Michael, 629 Blind staggers, 574 Blister copper, 539 Blood alcohol concentrations, 43t Body-centered cubic cell (BCC) A cubic unit cell with an atom at each comer and one at the center, 246 Bohrmodd Model of the hydrogen atom... 

For simplicity of the model, it is assumed that the natural convection, radiation, and ionic wind effect are ignored. The ignorance of the radiation loss from the spark channel during the discharge may be reasonable, because the radiation heat loss is found to be negligibly small in the previous studies [5,6]. The amount of heat transfer from the flame kernel to the spark electrodes, whose temperature is 300 K, is estimated by Fourier s law between the electrode surface and an adjacent cell. 

Current lung dosimetry models are based on the assumption that basal cells of the bronchial epithelium are the critical target cells for malignant transformation and that the alpha dose to these cells is the relevant radiation dose. 

The cone calorimeter used in this study (5) is a somewhat enlarged version of the model used at the National Institute of Standards and Technology in the United States. This particular equipment takes samples of size 20 cm x 20 cm mounted in a horisontal position on top of a load cell. Above the sample there is a cone heater and a spark ignitor. Gas samples are taken in fan ventilated exhaust duct mounted above the cone heater. The radiation used has been 50 kW/m2 and free convection ventilation over the sample. 

The crystal properties of pseudoephedrine hydrochloride were determined with a GE model XRD-6 x-ray diffractometer using Zr filtered MoK radiation on a crystal grown from water.8 Pseudoephedrine hydrochloride has an orthorhombic crystal system belonging to the P212121 space group. The cell dimensions are a=25.358 A, b=6.428 A, c=6.901 A with each cell containing four molecules. 

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