A new view of pulmonary edema and acute respiratory distress syndrome

The old division of lung edema into two categories--cardiogenic (hydrostatic) and noncardiogenic (increased permeability)--is no longer adequate. For instance, it fails to distinguish between the capillary leak caused by acute respiratory distress syndrome from that caused by interleukin-2 treatment. Further, it fails to account for the capillary leak ('stress-failure') that may accompany edema. A modern view of edema must recognize the natural barriers to the formation and spread of edema. These barriers are the capillary endothelium and the alveolar epithelium. Varying degrees of damage to them can account for the varying radiographic and clinical manifestations of lung edema. Thus, interleukin-2 administration causes increased endothelial permeability without causing alveolar epithelial damage. The result is lung edema that is largely confined to the interstitium, causing little hypoxia and clearing rapidly. However, acute respiratory distress syndrome, which is characterized by extensive alveolar damage, causes air-space consolidation, severe hypoxia, and slow resolution. Thus, a reasonable classification of lung edema requires at least four categories: 1) hydrostatic edema; 2) acute respiratory distress syndrome (permeability edema caused by diffuse alveolar damage); 3) permeability edema without alveolar damage; and (4) mixed hydrostatic and permeability edema. The authors emphasize the importance of the barriers provided by the capillary endothelium and the alveolar epithelium in determining the clinical and radiographic manifestations of edema. In general, when the alveolar epithelium is intact, the radiographic manifestations are those of interstitial (not air-space) edema; this radiographic pattern predicts a mild clinical course and prompt resolution.     

Subsurface Radioactive Contaminant Transport Modeling Using Particle and Kalman Filter Schemes

Contamination of groundwater by radioactive contaminants can be harmful to the environment. Various prediction models have been adopted to simulate the state of contaminants in the subsurface. Conventional numerical models are simplified by approximation and the model parameters are assumed to be constant, thereby introducing error to the prediction results. Particle and Kalman filters are used in this research to simulate the radioactive contaminant cobalt-57 transport in a subsurface environment by using a two-dimensional advection-dispersion model. A radioactive contaminant concentration was predicted spatially and temporally within boundary conditions. The errors in the prediction results were assessed by using the root-mean-square-error (RMSE) equation. The results show that the Kalman filter performs better than the particle filter when the prediction model is linear. Furthermore, the results from filters are closer to the true value in comparison with the numerical solution, and the filters are capable of reducing the RMSE of the numerical solution by approximately 80%.     

Perceptual and decisional factors influencing the discrimination of inversion in the Thatcher illusion.

The Thatcher illusion (Thompson, 1980) is considered to be a prototypical illustration of the notion that face perception is dependent on configural processes and representations. We explored this idea by examining the relative contributions of perceptual and decisional processes to the ability of observers to identify the orientation of two classes of forms—faces and churches—and a set of their component features. Observers were presented with upright and inverted images of faces and churches in which the components (eyes, mouth, windows, doors) were presented either upright or inverted. Observers first rated the subjective grotesqueness of all of the images and then performed a complete identification task in which they had to identify the orientation of the overall form and the orientation of each of the interior features. Grotesqueness ratings for both classes of image showed the standard modulation of rated grotesqueness as a function of orientation. The complete identification results revealed violations of both perceptual and decisional separability but failed to reveal any violations of within-stimulus (perceptual) independence. In addition, exploration of a simple bivariate Gaussian signal detection model of the relationship between identification performance and judged grotesqueness suggests that within-stimulus violations of perceptual independence on their own are insufficient for producing the illusion. This lack of evidence for within-stimulus configurality suggests the need for a critical reevaluation of the role of configural processing in the Thatcher illusion. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Heat Transfer Analysis for Gas-to-Liquids Transportation Through Trans Alaska Pipeline

Gas-to-liquids (GTL) technology involves the conversion of natural gas to liquid hydrocarbons. In this article, theoretical studies have been presented to determine the feasibility of transporting GTL products through the Trans-Alaska Pipeline System (TAPS). To successfully transport GTL through TAPS, heat loss along the route must be carefully determined. This study presents heat transfer and fluid dynamic calculations to evaluate this feasibility. Because of heat loss, the fluid temperature decreases in the direction of flow and this affects the fluid properties, which in turn influence convection coefficient and pumping power requirements. The temperature and heat loss distribution along the pipeline at different locations have been calculated. Fairly good agreement with measured oil temperatures is observed. The powers required to pump crude oil and GTL individually, against various losses have been calculated. Two GTL transportation modes have been considered; one as a pure stream of GTL and the second as a commingled mixture with crude oil. These results show that the pumping power and heat loss for GTL are less than that of the crude oil for the same volumetric flow rate. Therefore, GTL can be transported through TAPS using existing equipment at pump stations.     

A New Method for the Study of Adhesion: Application of Inelastic Electron Tunneling Spectroscopy

Inelastic electron tunneling spectroscopy provides an incredibly sensitive and versatile method of detecting and identifying molecular species adsorbed on the surface of a metal oxide. IETS spectra have been measured on the components of the commercial adhesive, Hercules 3501. This epoxy system consists of two molecular components; diamino diphenyl sulfone (DPS) and tetraglycidycl 4,4' diamino diphenyl methane (DPM). IETS spectra of the individual components and of the epoxy mixture adsorbed on aluminum oxide have been obtained and the vibrational modes and frequencies assigned by comparison with computer calculations and existing infrared optical spectra.

IETS is a useful tool for the study of molecular adhesion to an oxide. It is one of the most important methods available for determining the interface physics and chemistry of adhesive bondlines. Its usefulness is greatly enhanced by the fact that in situ studies can be made.

Spectra have been obtained on the components and mixture of the high performance, two component epoxy Hercules 3501. The vibrational modes were identified by comparison with infrared and Raman data, and with computer calculations using force constant information. Evidence for an aging effect was found in the DPS component.

It is suggested that initial studies using IETS should be applied to adhesives of simple molecular structure before proceeding to more complex systems.     

Plasticizer factors influencing take-up by PVC resins

The ease with which plasticizer is combined with poly(vinyl chloride) resin is a measure of processing characteristics critical in the dry blending of suspension PVC and the gelation of plastisols. By using commercial grade plasticizers, this study developed predictive equations for the following processing parameters of dialkyl phthalates in PVC:

• Relative dry-blend rates in suspension PVC as a function of plasticizer viscosity.
• Relative initial gelation temperatures in plastisols as a function of plasticizer molecular weight and solvating strength.
• Relative final gelation temperatures in plastisols as a function of plasticizer solvating strength.

This information allows one to predict the relative processing characteristics of any dialkyl phthalate plasticizer for PVC on the basis of its chemical and physical properties.     

Sub-surface injection of liquid waste

The sub-surface injection of sewage sludge in grassland conditions has been investigated showing that injection is a viable alternative technique to surface applications. With the large amounts of existing liquid wastes, either municipal or agricultural, the land required for injection has risen over the available grassland. This study has considered the sub-surface injection of sewage sludge in a growing crop of spring wheat.The agronomic response of spring wheat has been compared at three different levels of crop development. Five different techniques were used to inject the sludge, and compared with two control situations. Using a three leg injector, with the outside tines bent, and placing gaps between rows for the tines and wheels, the crop showed a better agronomic response at the final levels of development.Analysing row by row the dry matter production in the injected plots, it was clear that the lower global production per square metre was due to the damage caused in the rows by the legs and traffic.