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Dancik Y.,University of Queensland | Dancik Y.,University of South Australia | Favre A.,University of Queensland | Loy C.J.,Singapore Research Center | And 3 more authors.
Journal of Biomedical Optics | Year: 2013

There is a growing body of literature showing the usefulness of multiphoton tomography (MPT) and fluorescence lifetime imaging for in situ characterization of skin constituents and the ensuing development of noninvasive diagnostic tools against skin diseases. Melanin and pigmentation-associated skin cancers constitute some of the major applications. We show that MPT and fluorescence lifetime imaging can be used to measure changes in cutaneous melanin concentration and that these can be related to the visible skin color. Melanin in the skin of African, Indian, Caucasian, and Asian volunteers is detected on the basis of its emission wavelength and fluorescence lifetimes in solution and in a melanocyte-keratinocyte cell culture. Fluorescence intensity is used to characterize the melanin content and distribution as a function of skin type and depth into the skin (stratum granulosum and stratum basale). The measured fluorescence intensities in given skin types agree with melanin amounts reported by others using biopsies. Our results suggest that spatial distribution of melanin in skin can be studied using MPT and fluorescence lifetime imaging, but further studies are needed to ascertain that the method can resolve melanin amount in smaller depth intervals. © 2013 Society of Photo-Optical Instrumentation Engineers.

Chittimalla S.K.,Singapore Research Center | Bandi C.,Singapore Research Center
RSC Advances | Year: 2013

A facile process for the synthesis of highly substituted bicyclo[4.1.0]heptenones via Corey-Chaykovsky reaction of quinone monoketals is presented. The obtained products were employed to functionalize 3-position of indoles providing compounds which might have potential use in medicinal chemistry. © 2013 The Royal Society of Chemistry.

Chittimalla S.K.,Singapore Research Center | Bandi C.,Singapore Research Center
Tetrahedron Letters | Year: 2015

o-Quinone monoketals participated in a 1,4-addition reaction with HCl furnishing m-chlorophenols in high yields. Several readily available o-quinone monoketals were selected to display the generality of this serendipitous and unprecedented reaction and the results are presented herein. © 2015 Elsevier Ltd.

Chittimalla S.K.,Singapore Research Center | Kuppusamy R.,Singapore Research Center | Chakrabarti A.,Singapore Research Center
Synlett | Year: 2012

A simple and efficient access to highly functionalized isoindolone derivatives via a [3+2] cycloaddition process between in situ generated azomethine ylides with various stable (isolable) masked o-benzoquinones is described. This approach allows a rapid and general synthesis of isoindolones with substituents to further manipulate and elaborate the structural complexity. © Georg Thieme Verlag Stuttgart · New York.

Chittimalla S.K.,Singapore Research Center | Bandi C.,Singapore Research Center | Putturu S.,Singapore Research Center
RSC Advances | Year: 2015

A rapid process for the synthesis of functionally rich benzobicyclo[2.2.2]octadienone derivatives has been realized through oxidative dimerization of commercially/readily available 2-methoxyphenols followed by an aromatization sequence. © The Royal Society of Chemistry 2015.

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