Fatty acid metabolism inTaphrina deformans treated with sterol biosynthesis inhibitors

Changes in the unsaturated fatty acid content of the fungusTaphrina deformans as a function of growth, temperature, and sterol content were investigated. It was found that the highest growth rate was accompanied by a relatively high degree of fatty acid unsaturation (18∶1<18∶2+18∶3) and low sterol (brassicasterol) content. Also, a substantial shift in the degree of unsaturation from mainly 18∶2+18∶3 to 18∶1 occurred in the later stages (mid-linear) of culture development. Cells readily adapted from 18°C to 13°C, and exhibited a higher growth rate at the lower temperature after a period of acclimation. Growth was readily inhibited by the sterol biosynthesis inhibitors propiconazole and naftifine, which blocked brassicasterol biosynthesis at C-14 demethylation and squalene epoxidation, respectively. Growth was also inhibited by tunicamycin which did so without affecting sterol content. The shift in degree of fatty acid unsaturation did not occur in cells from cultures at reduced temperature or treated with any of the inhibitors. Since tunicamycin did not affect the sterol content, delay in the shift in the degree of fatty acid unsaturation was attributed to factors other than a reduction in sterol content. Based on a paper presented at the Symposium on Plant and Fungal Sterols: Biosynthesis, Metabolism and Function, held at the AOCS Annual Meeting, Baltimore, MD, April 1990.     

High heat vinyl alloys for injection molding applications

Excessive distortion, warpage, and sagging resulting from heat generation by electrical components and transporting environments has limited the penetration of PVC into high flow injection molding applications such as business machine, appliance, and electrical housings. High flow PVC formulations lose their rigidity at temperatures typical of these applications because the application temperatures are very close to the glass transition temperature (T_g) of PVC. In addition, thermal stresses built in during processing relax near the T_g of the material. Adding a glutarimide acrylic copolymer increases the T_g of PVC; consequently, raising the temperature at which the PVC/glutarimide copolymer blend loses its rigidity well above required application temperatures. This paper describes the effect of adding a glutarimide copolymer on the heat distortion properties and other physical and rheological properties important to high flow injection molding applications.     

Review Paper: Human factors of stereo displays: An update

Abstract— This updated review paper provides a selected review of a number of important perceptual and human‐factors issues that arise when stereo displays are designed and used. This review and analysis draws heavily from the basic vision literature in order to help provide insight for future design solutions for stereo displays. Issues discussed include: (1) the basics of human stereopsis (horopter, binocular disparity, binocular rivalry); (2) low‐level factors (interocular cross talk, interocular differences in luminance and contrast, accommodation‐vergence mismatch, stereoanomaly); (3) contextual factors (spatio‐temporal frequency effects, distance scaling of disparity); and (4) a high‐level cognitive factor (high‐level cue conflict). In this updated review, significant new material has been added: (1) interocular luminance and contrast differences and their effect on stereo viewing; (2) more insightful discussion of accommodative‐vergence mismatch; (3) high‐level cognitive factor. Two topics in the earlier review (visual pathways; dark focus and dark vergence) have been deleted. The paper concludes with the presentation of several recommendations for the design of stereo displays.     

Characterization of Fluorescence Lifetime of Photofrin and Delta-Aminolevulinic Acid Induced Protoporphyrin IX in Living Cells Using Single- and Two-Photon Excitation

Photodynamic therapy (PDT) is an effective treatment option for various types of invasive tumors. The efficacy of PDT treatment depends strongly on selective cell uptake and selective excitation of the tumor. The characterization of fluorescence lifetimes of photosensitizers localized inside living cells may provide the basis for further investigation of in vivo PDT dosage measurements using time-domain spectroscopy and imaging. In this communication, we investigated the fluorescence lifetime of localized Photofrin and delta-aminolevulinic acid (ALA) induced protoporphyrin IX (PpIX) in living MAT-LyLu (MLL) rat prostate adenocarcinoma cells. The MLL cells were incubated with the photosensitizers, and then treated with light under well-oxygenated conditions using a two-photon fluorescence lifetime imaging microscope (FLIM). Fluorescence lifetime images of these cells were recorded with average lifetimes of 5.5 plusmn 1.2 ns for Photofrin and 6.3 plusmn 1.2 ns for ALA-induced PpIX. When localized in cells, the lifetimes of both photosensitizers were found to be significantly shorter than those measured in organic solutions. The result for PpIX is consistent with literature values, while the lifetime of Photofrin is shorter than what has been reported. These results suggest that time-domain methods measuring photosensitizer lifetime changes may be good candidates for in vivo PDT dosage monitoring.     

Combining Multicore Imaging Fiber With Matrix Addressable Blue/Green LED Arrays for Spatiotemporal Photonic Excitation at Cellular Level

We have developed a microscale flexible optical image projection device, integrating a matrix addressable blue/green 2-D LED array to a multicore imaging fiber. The scalable matrix addressing LED design was to enable electrical access to individual elements in the densely packed 2-D LED array. A prototype 10times10 element array was fabricated by specific device process sequence, using deep reactive ion etching and polyimide etch-back processes for device isolation and planarization. Individual elements of the array have been operated under continuous-wave current injection up to a few kiloamperes per square centimeter suggesting uncompromised performance and robustness of the planarized device structure. The device was butt-coupled to a 30 000 pixel multicore image fiber to generate a spatiotemporal pattern of light at the output end of the fiber. As application demonstrations, selected spatiotemporal patterns of illumination have been projected either to the eye of Xenopus laevis tadpoles in studies of their developing visual system, or directly to excitable neural cells in the brain.     

Sexual orientation across the life span: Introduction to the special section.

What impact does sexual orientation have on human development over the life span? As questions related to sexual orientation have become increasingly topics of public discussion and debate in recent years, psychological study of the issues has also burgeoned. What was once a new frontier for research has matured into a large, complex, and rapidly growing area of knowledge. Important research is being conducted on many issues, by diverse investigators, from a number of theoretical perspectives, in many parts of the world. The articles in this special section provide only a sampling of current research, but they begin to suggest the vitality and excitement of a field that is coming into its own. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Camera perspective bias in videotaped confessions: Evidence that visual attention is a mediator.

Several experiments have demonstrated a camera perspective bias in evaluations of videotaped confessions: videotapes with the camera focused on the suspect lead to judgments of greater voluntariness than alternative presentation formats. The present research investigated potential mediators of this bias. Using eye tracking to measure visual attention, Experiment 1 replicated the bias and revealed that changes in camera perspective are accompanied by corresponding changes in duration of fixation on the suspect and interrogator. A path analysis indicated that visual attention partially mediated the bias, with at least one additional factor independently contributing to it. A proposed second factor was changes in available visual content that naturally coincide with alterations in camera perspective. Experiment 2 directly manipulated observers' focus and thus more conclusively established visual attention as one mediator of the camera perspective bias. Together the two experiments provide plausible evidence that differences in visual content may also mediate the bias. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Calibration of a Speckle Interferometry Full-Field Strain Measurement System

Abstract:  This study describes the calibration of a full-field speckle interferometry strain measurement system using the calibration specimen and protocol defined in the Standardisation Project for Optical Techniques of Strain measurement (SPOTS) standard. The specimen was based on the monolithic embodiment of a four-point bending test and was manufactured from aluminium following the SPOTS design. Strain-gauge rosettes attached to the upper and lower faces of the beam were used to derive two correction factors of an analytical expression that predicted the strains generated in the gauge section of the beam. Following the SPOTS protocol, the comparison of measured and predicted strains yielded two fit parameters and their associated uncertainties for each of three displacement-load steps which indicated the closeness of the data sets. An acceptable calibration was achieved for the single normal component of in-plane strain considered in this study, for each load step employed. For the highest load range, which generated a maximum strain of approximately 810  μ strain in the gauge section, the overall calibration uncertainty was found to be 35.3  μ strain, which in relative terms can be expressed as 2.2% of the strain measurement range for which the instrument was calibrated.