Photoluminescence of the inorganic pigments Egyptian blue, Han blue and Han purple

The room-temperature photoluminescence spectra of various samples of Egyptian blue (CaCuSi₄O₁₀) are presented, discussed and compared with those of recently synthesized compounds corresponding to the ancient pigments Han blue (BaCuSi₄O₁₀) and Han purple (BaCuSi₂O₆). All the samples of Egyptian blue show identical spectra, in spite of their very different origin. The spectra of Han blue and Han purple are significantly different. Since the Cu²⁺ ion may be considered the only luminescent centre in the spectral range under investigation, the differences between the spectra of the various pigments are ascribed to a ligand-field change. This can be related to the larger size of the Ba²⁺ ion with respect to Ca²⁺. The use of PL spectra for the identification of these pigments in works of art is proposed.     

Leadership Development through Mentoring in Higher Education: A Collaborative Autoethnography of Leaders of Color

In this collaborative autoethnography, we explored how 14 academic and administrative leaders of color working in faith-based higher education have experienced personal and professional mentoring, and how mentoring experiences have influenced their leadership development. All participants identified a wide array of developmental relationships that had contributed to their leadership development, although not all of the relationships were labeled as mentoring. Whereas female participants (11 in total) relied on these relationships primarily for psychosocial support, three male participants had more actively sought out mentoring relationships to develop career skills and expand their professional network. Particularly, for the female participants, mentoring took place mostly outside their professional settings. We argue that personal and institutional factors contributed to the participants’ limited access to professional mentoring within their higher education contexts. This collaborative autoethnography process, which lasted at least six months for most participants, unexpectedly provided professional mentoring opportunities for these leaders of color.