Publications by authors named "Donald J Lyman"

Changes in the Synchrotron x-ray diffraction pattern of scalp hair were shown to occur in patients with breast cancer. A preliminary Fourier transform infrared (FT-IR) spectroscopy study of scalp hair using attenuated total reflection (ATR) supported the concept that these changes are due to an increase in the lipid content of the hair fibre. This study was undertaken to determine whether the ATR-FT-IR spectrum obtained using a single hair fibre ATR cell could be used in the detection of breast cancer.

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The structure of human hair was studied by attenuated total reflection Fourier transform infrared (ATR-FT-IR) spectroscopy. The use of Ge, ZnSe, and Si internal reflection elements, various incident light angles, and difference spectra allowed detailed analysis of the cuticle, cortex, and cuticle-cortex intercellular regions without physically or mechanically removing the cuticle of the hair fiber. The ATR-FT-IR data showed the cuticle to be composed of protein having predominantly beta-sheet and disorder and beta-turn configurations.

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A polyester (PET) reinforced fibrin-FN-VEGF-TGFbeta vascular graft, formed by a four-step preclotting technique of a porous PET arterial graft, shows the overlapping inflammation, proliferation, and remodeling steps of normal wound healing when implanted in the descending thoracic aorta (DTA) position in the dog, forming a surface layer of endothelial cells. While the DTA grafts readily healed (i.e.

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A comparative study of Fourier transform infrared attenuated total reflection (FTIR-ATR) spectra of 32 scalp and pubic hair samples from individuals diagnosed with breast cancer and those who were negative for breast cancer showed increases in the beta-sheet/disorder structures (relative to alpha-helix structures) and C-H lipid content of hair from breast cancer patients. Thus, the presence of breast cancer appears to alter the hair growth process, resulting in changes in the composition and conformation of cell membrane and matrix materials of hair fiber. These appear to be consistent with the changes observed in X-ray diffraction patterns for hair from breast cancer patients.

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Small-diameter vascular graft failure by intimal hyperplasia and thrombosis may result from flow disturbances and disruption of chemical transport in the fluid at the distal anastomosis, because of compliance mismatch between the graft and host artery. In previous studies. lower-than-normal wall shear stress (WSS), particle trapping, and high particle residence times were observed at the distal anastomosis due to a pulsatile tubular expansion effect caused by nonuniform radial deformations.

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A bigraft, composed of a 30-microm internodal distance expanded polytetrafluoroethylene (ePTFE) arterial graft segment and a preclotted polyethylene terephthalate arterial graft segment, was used to study the healing process of two different materials in the same dog. Healing was followed by FTIR-ATR spectroscopy and correlated with ELISA analyses of selected growth factors and matrix proteins. The FTIR analyses of the ePTFE explants from 1 and 3 h; 3, 5, 7, 10, and 14 days; and 4 and 8 weeks showed that the ePTFE grafts did not heal (endothelialize), but appeared to remain in overlapping inflammation and proliferation stages of wound healing.

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FTIR-ATR was used to study the effect of roasting conditions on the flavor of brewed coffee using Guatemala Antigua coffee beans. The 1800-1680 cm(-1) carbonyl region for vinyl esters/lactones, esters, aldehydes, ketones, and acids was found to provide a flavor-print of the brewed coffee. A study of light, medium, and dark roasts indicated that when the rate of heating to the onset of the first and second cracks was kept constant, the types of carbonyl compounds formed were similar, varying only in their concentration.

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