Introduction of a nonlinearity measure for principal component models

Although principal component analysis (PCA) is an important tool in standard multivariate data analysis, little interest has been devoted to assessing whether the underlying relationship within a given variable set can be described by a linear PCA model or whether nonlinear PCA must be utilized. This paper addresses this deficiency by introducing a nonlinearity measure for principal component models. The measure is based on the following two principles: (i) the range of recorded process operation is divided into smaller regions; and (ii) accuracy bounds are determined for the sum of the discarded eigenvalues. If this sum is within the accuracy bounds for each region, the process is assumed to be linear and vice versa. This procedure is automated through the use of cross-validation. Finally, the paper shows the utility of the new nonlinearity measure using two simulation studies and with data from an industrial melter process.     

Prednisolone therapy of idiopathic feline lower urinary tract disease: a double-blind clinical study

A double-blind clinical study was performed to evaluate prednisolone as treatment for idiopathic feline lower urinary tract disease. No differences in response were observed in prednisolone- and placebo-treated cats.     

Chlorisondamine inhibits the nicotine-induced stimulation of c-fos in the pigeon brain for up to 2 weeks.

Chlorisondamine is a charged molecule that acts as long-acting nicotinic antagonist in many species, including pigeon. Evidence indicates that, despite the charged nature of chlorisondamine, it blocks some central effects of nicotine. The present study examined the time course of chlorisondamine's blockade of nicotine-induced c-fos expression in the pigeon brain. Chlorisondamine's central blockade was examined from 1 hr to 28 days prior to nicotine administration. Nicotine stimulated increases in c-fos mRNA in the hippocampus, hyperstriatum accessorium, hyperstriatum ventrale, nucleus accumbens, bulbus olfactorius, paleostriatum augmentatum, and stratum griseum et fibrosum superficiale. Nicotinic receptors labeled by [(125)I]-epibatidine were not always found in the same regions as nicotine-induced increases in c-fos expression. Acute chlorisondamine increased the level of c-fos mRNA in the cerebellum, hippocampus, hyperstriatum accessorium, locus parolfactorius, nucleus accumbens, tectum opticum, paleostriatum augmentatum, and stratum griseum et fibrosum superficiale but had no effect on its own 24 hr after administration. Chlorisondamine blocked nicotine-induced increases in c-fos RNA for 4 days in the nucleus accumbens, a week in the bulbus olfactorius, and 2 weeks in the stratum griseum et fibrosum superficiale. The time course of chlorisondamine's blockade of nicotine-induced c-fos expression is consistent with the time course of the ability of chlorisondamine to block behavioral and physiological responses to nicotine.     

Identification and characterization of a two-component regulatory system involved in invasion of eukaryotic cells and heavy-metal resistance in Burkholderia pseudomallei

Burkholderia pseudomallei is the causative agent of melioidosis, a disease increasingly recognized as an important cause of morbidity and mortality in many regions of the world. B. pseudomallei is a facultative intracellular pathogen capable of invading eukaryotic cells. We used Tn5-OT182 mutagenesis to generate mutants deficient in the ability to invade a human type II pneumocyte cell line (A549 cells). One of these mutants, AJ1D8, exhibited approximately 10% of the ability of the parental strain, 1026b, to invade A549 cells. There was no difference in the abilities of 1026b and AJ1D8 to resist killing by RAW macrophages or the human defensin HNP-1. The nucleotide sequence flanking the Tn5-OT182 integration in AJ1D8 was determined, and two open reading frames were identified. The predicted proteins shared considerable homology with two-component regulatory systems involved in the regulation of heavy-metal resistance in other organisms. AJ1D8 was 16-fold more sensitive to Cd2+ and twofold more sensitive to Zn2+ than was 1026b but was not sensitive to any of the other heavy metals examined. The B. pseudomallei two-component regulatory system, termed irlRS, complemented the invasion-deficient and heavy-metal-sensitive phenotype of AJ1D8 in trans. There was no significant difference between the virulence of AJ1D8 and that of 1026b in infant diabetic rats and Syrian hamsters, suggesting that the irlRS locus is probably not a virulence determinant in these animal models of acute B. pseudomallei infection.     

The impact of III-V semiconductors on microelectromechanicalsystems

This article examines the special features of the III-V semiconductors, such as gallium arsenide and chemically related compounds, which make them an attractive alternative to silicon-based technology in the field of microelectromechanical systems. As in conventional electronic systems, it is not expected that the III-V compounds will become exclusively used in all instances, but rather a substantial niche market-exploiting the special advantages of the compound semiconductors-is likely to be established     

Evaluation of capital cost data. part 7: Liquid waste disposal with emphasis on physical treatment

Capital cost correlations are given for oil-water separators, equalization basins, primary clarifiers, clarifiers and clarifier mechanisms, reverse osmosis unit, ultrafiltration units, gravity filters and miroscreens. Data are included for raw sewage, intermediate and recirculation pumping stations and for preliminary treatment (or bar screens, grit removal, overflow and bypass chamber and Parshall flume), for grit removal, comminution and gas stripping. The correlations are accurate to ± 30%, expressed in Canadian dollars and adjusted to a Marshall and Swift value of 1000. Details as to what components are included in the cost are given. Data are given for the labour and material costs to create a working process module. For inflation indices, a critique of the Engineering News Record, EPA small city, Marshall and Swift, Chemical Engineering and Southam inflation indices suggested that the Marshall and Swift index is most appropriate for the construction and process equipment studied here. Concerning the currency exchange, for the equipment and processes in this study, equipment costs the same whether expressed directly in US or Canadian dollars. To put the current data into perspective, several hundred sources of cost data were analyzed. The major correlations are compared, on a consistent basis, with current data.     

Testing of the multi-application small light water reactor (MASLWR) passive safety systems

Experimental thermal hydraulic research has been conducted at Oregon State University for the purpose of assessing the performance of a new reactor design concept, the multi-application small light water reactor (MASLWR). The MASLWR is a pressurized light water reactor design with a net output of 35 MWe that uses natural circulation in both normal and transient operation. Due to its small size, portability and modularity, the MASLWR design is well suited to help fill the potential need for grid appropriate reactor designs for smaller electricity grids as may be found in developing or remote regions. The purpose of the OSU MASLWR test facility is to assess the operation of the MASLWR under normal full operating pressure and full temperature conditions and to assess the passive safety systems under transient conditions. The data generated by the testing program will be used to assess computer code calculations and to provide a better understanding of the thermal-hydraulic phenomena in the design of the MASLWR NSSS. During this testing program, four tests were conducted at the OSU MASLWR test facility. These tests included one design basis accident and one beyond design basis accident. During the performance of these tests, plant operations to include start up, normal operation and shut down evolutions were demonstrated successfully.     

Thermodynamic equations of state for hydrazine and monomethylhydrazine

Thermodynamic equations of state are evaluated for the aerospace fuels hydrazine and monomethylhydrazine using Peng-Robinson (PR) and Soave-Redlich-Kwong (SRK) formulations. The PR formulation is shown to be the best fit for hydrazine, and the SRK formulation to be the best fit for monomethylhydrazine, based on available critical property data and evaluations of thermodynamic consistency. The adequacy of the differing property data for these fuels in the literature is discussed, and the methodology used to validate the formulations is outlined. The importance of using appropriate real fluid equations of state in thermodynamic safety and hazards analysis of fuel systems is demonstrated by considering an adiabatic compression of gaseous fuels previously postulated in accident scenarios of aerospace propulsion systems. Calculation of isentropic compression temperatures for pure components using ideal gas constant heat capacity, ideal gas with variable heat capacity, and real fluid equations of state are compared to illustrate the need for real fluid equations of state. In addition, three separate approaches are used for estimating isentropic compression temperatures for mixtures involving these fuels, again illustrating the importance of treating these mixtures as real fluids for design and safety analysis.     

Photoacoustic ultrasound: pulse production and detection of 0.5% Liposyn

Theoretical predictions and experimental measurements of photoacoustic pulse production within a 0.5% solution of Liposyn, a highly scattering, optical propagation medium, are reported. A simple model for photoacoustic energetics is developed that predicts photoacoustic signal pressure as a function of depth within a turbid medium following surface irradiation from an infrared source. The model is valid for very short irradiation duration. The model predicts that the acoustic pressure produced at a distance r from the center of a small, highly absorbing sphere of radius R consists of two, opposite polarity pulses, one originating from the near and one from the far side of the sphere. The magnitude of these biphasic pulses is expected to be proportional to the energy fluence (E) incident on the surface of the sphere and to the ratio, R/r. Furthermore, the energy fluence (E) that reaches the sphere is roughly proportional to e-mu effZ, where mu eff is the effective attenuation coefficient of the turbid medium and Z is the depth of the embedded sphere below the irradiated surface. The variation of E with depth within the absorber and biphasic acoustic pulse production have been verified experimentally. Further experiments demonstrate that a small (3-mm diameter), highly absorbing sphere can be detected and localized at a depth of 37.5 mm within a 0.5% solution of Liposyn with a spatial resolution of 1 x 6 mm2, using a biologically safe level of infrared irradiation (lambda = 1064 nm) and a conventional ultrasound transducer (frequency = 2.25 MHz). These results suggest that photoacoustic ultrasound imaging may have application to biologic systems such as the human breast.