Luminescence nanothermometry using a trivalent lanthanide co-doped perovskite.

This study investigates in detail the laser-mediated upconversion emission and temperature-sensing capability of (Ca0.99-a Yb0.01Er a )TiO3. Samples were prepared at different concentrations to observe the effect of erbium on upconversion while increasing its concentration and keeping all the other parameters constant. Doping is a widespread technological process which involves incorporating an element called a dopant in a lower ratio to the host lattice to derive hybrid materials with desired properties. The (Ca0.99-a Yb0.01Er a )TiO3 perovskite nanoparticles were synthesized via a sol-gel technique. The frequency upconversion was performed using a 980 nm laser diode excitation source. X-ray diffractometry (XRD) confirmed that the synthesized samples are crystalline in nature and have an orthorhombic structure. The temperature-sensing ability was examined using the fluorescence intensity ratio (FIR) algorithm of two emission bands (2H11/2 → 4I15/2 and 4S3/2 → 4I15/2) of the Er3+ ion. Temperature-dependent upconversion luminescence is observed over a broad temperature range of 298-623 K. The maximum sensor sensitivity obtained is 6.71 × 10-3 K-1 at 110°.

Degrading ability and robust antioxidative defence system led to SDS tolerance in cyanobacterium Fischerella sp. lmga1.

To test the tolerance and degradation potential of the cyanobacterium Fischerella sp. lmga1 for surfactant, sodium dodecyl sulfate (SDS), different doses of SDS (10, 30, 40, 50, 70 and 100 µM) were used for the growth. The lower doses of SDS supported the growth of cyanobacterium whereas the higher doses were found to be inhibitory but the cyanobacterium somehow managed its survival up to 100 µM SDS. However, a significant reduction was observed in the pigment and protein content. A substantial accumulation of carbohydrate at 70 µM SDS may act as an osmoprotectant for the survival of the cyanobacterium. The higher doses of SDS also triggered the ROS generation and lipid peroxidation which showed negative impact on the PSII efficiency. Simultaneously, an efficient ROS mitigation system (SOD and CAT activity) has also been worked up to 70 µM SDS while APX was enhanced only up to 50 µM SDS. Furthermore, the SDS degrading potential was investigated and almost 80% of the SDS was degraded after 6th days of treatment in the cyanobacterium. Hence, the results suggested that due to robust antioxidative defence system and ability to degrade the surfactant this cyanobacterium showed significant tolerance toward SDS.