The purpose of this study was to determine the accuracy and practical utility of a noncontact laser Doppler imager (PIM-II, Lisca Development AB, Linköping, Sweden) in the estimation of burn depth in the upper and lower extremities. At 48 hours after burn injury, we performed scans of 35 burns in 22 patients and obtained histological samples for burn determination with hematoxylin and eosin and vimentin immunohistochemical staining. Additionally, sequential scans and tissue specimens were obtained on 10 burns at 24, 48, and 72 hours. A statistically significant inverse relationship was noted between burn depth and the laser Doppler perfusion index. Laser Doppler perfusion index values greater than 1.3 predicted a superficial dermal burn with 95% sensitivity and 94% specificity. Superficial dermal burns exhibited increased perfusion in the early burn period. Wounds showed a progressive decline in perfusion and a progressive increase in the depth of injury during a 72-hour period. This study demonstrates the advantage and accuracy of using a noncontact laser Doppler to differentiate deep dermal from superficial partial thickness burns in the extremities.

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Mechanical properties of thin films differ significantly from those of bulk materials due to the effects of interfaces, microstructure and thick underlying substrates. In this study we will present the results of nanoindentation tests to evaluate mechanical properties of nitride (TiN, ZrN, CrN, TiCN and TiAlN) thin films. Films were coated on steel substrates using cathodic arc deposition technique. Surface morphology and roughness of the samples are investigated using atomic force microscopy (AFM). Films were also characterized by x-ray diffraction (XRD) technique. Nanoindentation technique along with AFM and XRD methods are very useful for characterizing hard thin coatings.