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The innovative strategy of using nanoparticles in radiotherapy has become an exciting topic due to the possibility of simultaneously improving local efficiency of radiation in tumors and real-time monitoring of the delivered doses. Yttrium oxide (Y2O3) nanoparticles (NPs) are used in material science to prepare phosphors for various applications including X-ray induced photodynamic therapy and in situ nano-dosimetry, but few available reports only addressed the effect induced in cells by combined exposure to different doses of superficial X-ray radiation and nanoparticles. Herein, we analyzed changes induced in melanoma cells by exposure to different doses of X-ray radiation and various concentrations of Y2O3 NPs. By evaluation of cell mitochondrial activity and production of intracellular reactive oxygen species (ROS), we estimated that 2, 4, and 6 Gy X-ray radiation doses are visibly altering the cells by inducing ROS production with increasing the dose while at 6 Gy the mitochondrial activity is also affected. Separately, high-concentrated solutions of 25, 50, and 100 µg/mL Y2O3 NPs were also found to affect the cells by inducing ROS production with the increase of concentration. Additionally, the colony-forming units assay evidenced a rather synergic effect of NPs and radiation. By adding the NPs to cells before irradiation, a decrease of the number of proliferating cell colonies was observed with increase of X-ray dose. DNA damage was evidenced by quantifying the γ-H2AX foci for cells treated with Y2O3 NPs and exposed to superficial X-ray radiation. Proteomic profile confirmed that a combined effect of 50 µg/mL Y2O3 NPs and 6 Gy X-ray dose induced mitochondria alterations and DNA changes in melanoma cells.

Laser Melting Deposition (LMD) is a metal printing technique that allows for the manufacturing of large objects by Directed Energy Deposition. Due to its versatility in variation of parameters, the possibility to use two or more materials, to create alloys in situ or produce multi-layer structures, LMD is still being scientifically researched and is still far from industrial maturity. The structural testing of obtained samples can be time consuming and solutions that can decrease the samples analysis time are constantly proposed in the scientific literature. In this manuscript we present a quality improvement study for obtaining defect-free bulk samples of Ti6Al4V under X-Ray Computed Tomography (XCT) by varying the hatch spacing and distance between planes. Based on information provided by XCT, the experimental conditions were changed until complete elimination of porosity. Information on the defects in the bulk of the samples by XCT was used for feedback during parameters tuning in view of complete removal of pores. The research time was reduced to days instead of weeks or months of samples preparation and analysis by destructive metallographic techniques.

Herein, we report the luminescence properties of (1%) Ho and (1%) Ho, (20%) Yb–CeO 2 nanoparticles, investigated by time-resolved luminescence spectroscopy at 300 and 80 K temperatures. The emission was measured over a broad detection range, from visible (450 nm) up to infrared (1500 nm) with excitation ranging from 210 to 1000 nm. The structural properties were characterized by X-ray diffraction, Raman, Diffuse Reflectance Optical and Diffuse Reflectance Fourier Transform Infrared spectroscopies. The up-conversion emission of Ho–CeO 2 and Ho, Yb–CeO 2 using excitation wavelengths of 646.6, 759, 918 and 971 nm, respectively, were described in terms of time-gated up-conversion emission and excitation spectra, as well as up-conversion emission decays. Under short gate/ short delay conditions, the contribution of the 5 F 3 and 5 F 5 energy levels to the red emission of Ho at 630–680 nm could be separated. The role of CeO 2 charge transfer band as a selective antenna sensitizer as well as back transfer of excitation from Ho to Yb was also discussed. The mechanisms involved in the up-conversion emission of Ho and Ho, Yb–CeO 2 were interpreted as ground state absorption followed by excited state absorption and energy transfer, respectively. For Ho, Yb–CeO 2 , a tunable red to green up-conversion emission ratio from 0.5 to 3.6 was also observed by increasing the power density of ~4 to 48 W/cm 2 of a cw laser diode at 980 nm.

In recent years, luminescence nanothermometers with near infrared light (NIR) emission excited in the NIR range have attracted much attention due to their potential in bio applications. Here, we propose a new nanothermometer based on triple doped 1%Ho, 1%Er, 1%Yb - Y2O3 that operates in the second and third biological windows around 1200 and 1530 nm under pulsed excitation at 905 nm. The NIR emissions were analysed in the temperature range of 298-473 K in terms of intensity, shape and dynamics. The nanothermometer performances were described using the luminescent intensity ratio (LIR) corresponding to the 5I6-5I8 and 4I13/2-4I15/2 emissions transitions of Ho and Er, respectively. A maximum relative sensitivity of 1.5% K-1 was achieved at 309 K, which is among the highest five values reported so far for the NIR to NIR downconversion nanothermometers. The thermometer performance for biological application was assessed in terms of nanothermometer reliability and stability as well as emission shape changes induced by water and custom designed optical phantoms. Combination between use of pulsed excitation and identification of Ln doping configuration offering both excitation and emission in the biological windows represent a solid approach that can be easily translated to other hosts to develop a new class of near infrared nanothermometers.