In the aerospace industry, composites based on polymer or metal matrices and fillers made from granite, marble, lime and other rock powders are used. These fillers are similar in composition to cement and glass used for immobilization of radioactive waste (RW). In this paper, it is proposed to grind cemented or vitrified radioactive waste into micro or nanopowder and introduce this powder into a polymer or metal matrix to obtain a composite with improved physical characteristics, which can be used as a structural element or equipment element of automated space stations, satellites or rovers. In this way, it is possible to dispose of a huge amount of accumulated radioactive waste into space as a payload.

Traditional photodynamic therapy (PDT), a clinical cancer therapeutic approach using light in killing cancer cells, is often limited by insufficient light penetration, inefficient photosensitizer energy transfer, and inadequate oxygen in hypoxic tumors. Employing X-ray to activate photosensitizer in PDT can potentially overcome these limitations. Here, we compared protocols to synthesize a novel nano-photosensitizer composed of a europium-doped yttrium oxide core with a silica shell (Y₂O₃:Eu@SiO₂) which can be utilized in such therapeutic method, i.e., X-ray activated PDT (XPDT). Transmission electron microscopy (TEM) and dihydroethidium (DHE) were utilized to evaluate the effects of various synthesis conditions on the characteristics of Y₂O₃:Eu@SiO₂ and their ability to generate reactive oxygen species (ROS). The in vivo tumor suppression effects of the Y₂O₃:Eu@SiO₂ were assessed by ¹⁸F-fluorothymidine position emission tomography (¹⁸F-FLT PET) in human ovarian cancer xenografts using radiation sensitive CAOV3 and radiation resistant SKOV3 cell lines. Our data revealed a positive correlation between nanoparticle condensation time and core size as well as a negative correlation between urea concentrations and core size. Addition of cetyltrimethylammonium bromide (CTAB) during core synthesis enhanced particle dispersion. Two silica coating conditions showed the greatest efficiency in the enhancement of ROS generation. Furthermore, our in vivo study revealed suppression of tumor growth by Y₂O₃:Eu@SiO₂ administration when compared to non-treated control. Silica shell provides flexibility to conjugate moieties that specifically target to cancers. This nano-photosensitizer demonstrates the significant promise for overcoming limitations of conventional PDT and combating various cancers in clinical applications.

Backward electromagnetic waves are extraordinary waves with contra-directed phase velocity and energy flux. Unusual properties of the coherent nonlinear optical coupling of the phase-matched ordinary and backward electromagnetic waves with contra-directed energy fluxes are described which enable greatly-enhanced frequency and propagation direction conversion, parametrical amplification, as well as control of shape of the light pulses. Extraordinary transient processes that emerge in such metamaterials in pulsed regimes are described. The results of the numerical simulation of particular plasmonic metamaterials with hyperbolic dispersion are presented, which prove the possibility to match phases of such coupled guided ordinary and backward electromagnetic waves. Particular properties of the outlined processes in the proposed metamaterial are demonstrated through numerical simulations. Potential applications include ultra-miniature amplifiers, frequency changing reflectors, modulators, pulse shapers, and remotely actuated sensors.