Terahertz imaging of human skin pathologies using laser feedback interferometry with quantum cascade lasers.

Early detection of skin pathologies with current clinical diagnostic tools is challenging, particularly when there are no visible colour changes or morphological cues present on the skin. In this study, we present a terahertz (THz) imaging technology based on a narrow band quantum cascade laser (QCL) at 2.8 THz for human skin pathology detection with diffraction limited spatial resolution. THz imaging was conducted for three different groups of unstained human skin samples (benign naevus, dysplastic naevus, and melanoma) and compared to the corresponding traditional histopathologic stained images. The minimum thickness of dehydrated human skin that can provide THz contrast was determined to be 50 µm, which is approximately one half-wavelength of the THz wave used. The THz images from different types of 50 µm-thick skin samples were well correlated with the histological findings. The per-sample locations of pathology vs healthy skin can be separated from the density distribution of the corresponding pixels in the THz amplitude-phase map. The possible THz contrast mechanisms relating to the origin of image contrast in addition to water content were analyzed from these dehydrated samples. Our findings suggest that THz imaging could provide a feasible imaging modality for skin cancer detection that is beyond the visible.

Development and characterization of 59 polymorphic cDNA-SSR markers for the edible oil crop Sesamum indicum (Pedaliaceae).

PREMISE OF THE STUDY: Polymorphic simple sequence repeat markers from transcript sequences (cDNA-simple sequence repeat [SSR]) were developed for the edible oil crop Sesamum indicum to facilitate the genetic study of this species. • METHODS AND RESULTS: We found 7702 SSR loci in the 60960 unigenes, and 1550 primer pairs were designed and synthesized. In total, 59 primer pairs showed polymorphism within 36 individuals; the number of alleles per locus ranged from two to four, and the expected and observed heterozygosity ranged from 0.05 to 0.74 and 0 to 0.30, respectively. • CONCLUSIONS: These polymorphic markers will greatly facilitate studies of the genetic structure of S. indicum populations as well as the identification and conservation of the species.