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Tuning the nature of nitrogen atoms in N-containing reduced graphene oxide, Carbon (2015),

Radiation therapy along with chemotherapy and surgery remain the main cancer treatments. Radiotherapy can be applied to patients externally (external beam radiotherapy) or internally (brachytherapy and radioisotope therapy). Previously, nanoencapsulation of radioactive crystals within carbon nanotubes, followed by end-closing, resulted in the formation of nanocapsules that allowed ultrasensitive imaging in healthy mice. Herein we report on the preparation of nanocapsules initially sealing “cold” isotopically enriched samarium (152Sm), which can then be activated on demand to their “hot” radioactive form (153Sm) by neutron irradiation. The use of “cold” isotopes avoids the need for radioactive facilities during the preparation of the nanocapsules, reduces radiation exposure to personnel, prevents the generation of nuclear waste, and evades the time constraints imposed by the decay of radionuclides. A very high specific radioactivity is achieved by neutron irradiation (up to 11.37 GBq/mg), making the “hot” nanocapsules useful not only for in vivo imaging but also therapeutically effective against lung cancer metastases after intravenous injection. The high in vivo stability of the radioactive payload, selective toxicity to cancerous tissues, and the elegant preparation method offer a paradigm for application of nanomaterials in radiotherapy.

This paper reports on photoluminescence experiments in n-type indium selenide ͑T = 300 K͒ under hydrostatic pressure up to 7 GPa at low and high excitation densities. Photoluminescence measurements at low excitation density exhibit a broad band around the energy of the direct band gap of InSe and with the same pressure dependence. The reversible increase of its linewidth above 1 GPa is associated to a direct-to-indirect band-gap crossover between valence band maxima. The reversible decrease of its intensity above 4 GPa is interpreted as evidence of a direct-to-indirect band-gap crossover between conduction band minima. Photoluminescence measurements under high excitation density exhibit several spontaneous and stimulated emission bands. The different components of these bands can be attributed to radiative emission from different minima of the conduction band to different maxima of the valence band in the framework of the band-gap renormalization theory in a multivalley scenario. The image of the electronic band structure of InSe provided by these measurements agrees with the previous analysis of the optical absorption coefficient of InSe and In 1−x Ga x Se.