“
“Novel flexible polyurethane foams were successfully prepared from a renewable source, hydroxytelechelic ABT-263 chemical structure natural rubber (HTNR) having different molecular weights (1000-3400 g mol(-1)) and variation of epoxide contents (EHTNR, 0-35% epoxidation) by a one-shot technique. The chemical and cell structures as well as physico-mechanical, thermal, and acoustic properties were characterized and compared with commercial polyol analogs. The obtained HTNR based foams are open cell structures with cell dimensions between 0.38 and 0.47 mm. The

HTNR1000 based foam exhibits better mechanical properties but lower elongation at break than those of commercial polyol analog. However, the HTNR3400 based foam shows the best elastic properties. In a series of EHTNR based foams, the tensile and compressive strengths show a tendency to increase with increasing epoxide content and amount of 1,4-butanediol SCH 900776 (BD). The HTNR based foams demonstrate better low temperature flexibility than that of the foam based on commercial polyol. Moreover, the HTNR based polyurethane foams was found to be an excellent absorber of acoustics. (C) 2010 Wiley

Periodicals, Inc. J Appl Polym Sci 117: 828-837, 2010″
“PURPOSE: To evaluate the influence of spherical aberration on contrast sensitivity using adaptive optics.

SETTING: Vision Science and Advanced Retinal Imaging Laboratory, Department of Ophthalmology & Vision Science, University of California, Davis Medical Center, Sacramento, STI571 mw California, USA.

METHODS: Contrast sensitivity at 8 cycles per degree was evaluated using an adaptive optics system that permitted aberrations to be measured with a Hartmann-Shack wavefront sensor and controlled by a 109 actuator continuous-surface deformable mirror that was at a plane conjugate to the observer’s pupil. Vertical Gabor patches were viewed through a 6.3 mm diameter pupil conjugate aperture. Contrast sensitivity was measured

with the deformable mirror set to produce 1 of 5 spherical aberration profiles (-0.2 to +0.2 mu m). Contrast sensitivity over the range of spherical aberration was fitted with a polynomial function.

RESULTS: Three subjects (age 21 to 24 years) participated. The measured total mean spherical aberration resulting from the spherical aberration profiles produced by the deformable mirror was between -0.15 mu m and + 0.25 mu m. The peak contrast sensitivity of this function for the 3 subjects combined occurred at +0.06 mu m of spherical aberration. The peak contrast sensitivity was also achieved with positive spherical aberration for each subject’s data fitted individually (mean 0.09).

CONCLUSION: There was intersubject variability in the measurements; however, the mean visual performance was best with the introduction of a small positive spherical aberration.