Occurrence, physiological responses and toxicity of nickel in plants

The focus of the review is on the specific aspects of nickel's effects on growth, morphology, photosynthesis, mineral nutrition and enzyme activity of plants. The mobility of nickel in the environment and the consequent contamination in soil and water is of great concern. Also, the detrimental effects of excessive nickel on plant growth have been well known for many years. Toxic effects of nickel on plants include alterations in the germination process as well as in the growth of roots, stems and leaves. Total dry matter production and yield was significantly affected by nickel and also causes deleterious effects on plant physiological processes, such as photosynthesis, water relations and mineral nutrition. Nickel strongly influences metabolic reactions in plants and has the ability to generate reactive oxygen species which may cause oxidative stress. More recent evidence indicates that nickel is required in small amounts for normal plant growth and development. Hence, with the increasing level of nickel pollution in the environment, it is essential to understand the functional roles and toxic effects of nickel in plants

Green synthesis: In-vitro anticancer activity of copper oxide nanoparticles against human cervical carcino

Copper oxide nanoparticles (CuO NPs) were synthesized by a green route using an aqueous black bean extract and characterized by XRD, FT-IR, XPS, Raman spectroscopy, DLS, TEM, SAED, SEM, and EDX. The synthesized CuO NPs were spherical in shape, and the XRD results show the average size of the NPs was ∼26.6 nm. The cytotoxic effect of the CuO NPs was determined by sulforhodamine-B assay. Mitochondria-derived reactive oxygen species (ROS) were increased and initiated lipid peroxidation of the liposomal membrane, which regulates several signaling pathways and influences the cytokinetic movements of cells. Mitochondrial fragmentation disruption assay confirmed the alteration in the mitochondrial structure after incubation with nanoparticles. In addition, clonogenic assay confirmed the inability of NPs incubated cancer cells to proliferate well. Our experimental results show that the CuO NPs can induce apoptosis and suppress the proliferation of HeLa cells

Thermal sensing in NIR to visible upconversion of Ho3+ and Yb3+ doped yttrium oxyfluoride phosphor

Rare-earth (RE) oxyfluorides compatible for RE doping make a path for efficient near-infrared (NIR) to visible upconversion (UC). This paper describes the efficient use of YOF:Ho3+/Yb3+ phosphor nanoparticles synthesised by the Pechini sol-gel method as thermal sensors using UC in the visible region. Material characterisations such as X-ray diffraction, Raman spectroscopy and scanning electron microscopy (SEM), revealed the structural information of the material and its prominence for RE doping. Average size of 44 nm obtained from SEM with maximum phonon energy of 480 cm− 1 observed from Raman measurements assure the use of RE doped YOF for UC. Excitation of YOF:Ho3+/Yb3+ with NIR (980 nm) revealed intense UC emission in the visible and DS in the NIR region. Although Ho3+ and Yb3+ ions do not have resonance energy levels at 980 nm, three two-photon UC emission bands centred at 538, 655 and 755 nm from 5 F4+5 S2→5 I8, ( 5 F5→5 I8+5 F3→5 I7) and 5 F4+5 S2→5 I7 transitions were obtained through phonon-assisted energy transfer. For the evaluation of thermal sensitivities using 980 nm excitation, fluorescence intensity ratio (FIR) was used based on the thermally non-coupled levels in the visible UC bands between the temperatures 20–300 K. The relative sensitivities (SR) which is the measure of temperature sensing ability of YOF materials with 1 mol % Ho3+ and 10 mol % Yb3+ was found to be 0.32 for UC in visible region was achieved with 980 nm excitation at 300 K.publishe