Narendra Singh

Bio: Narendra Singh is an academic researcher from Aryabhatta Research Institute of Observational Sciences. The author has contributed to research in topics: Excited state & Nanoparticle. The author has an hindex of 48, co-authored 289 publications receiving 8375 citations. Previous affiliations of Narendra Singh include University of Toronto & Tsinghua University.

Recycling of Spent Lithium-Ion Battery: A Critical Review

Abstract: Lithium-ion battery (LIB) applications in consumer electronics and electric vehicles are rapidly growing, resulting in boosting resources demand, including cobalt and lithium. So recycling of batteries will be a necessity, not only to decline the consumption of energy, but also to relieve the shortage of rare resources and eliminate the pollution of hazardous components, toward sustainable industries related to consumer electronics and electric vehicles. The authors review the current status of the recycling processes of spent LIBs, introduce the structure and components of the batteries, and summarize all available single contacts in batch mode operation, including pretreatment, secondary treatment, and deep recovery. Additionally, many problems and prospect of the current recycling processes will be presented and analyzed. It is hoped that this effort would stimulate further interest in spent LIBs recycling and in the appreciation of its benefits.

Characterization of Osmotin : A Thaumatin-Like Protein Associated with Osmotic Adaptation in Plant Cells

Abstract: Cultured tobacco (Nicotiana tabacum var Wisconsin 38) cells adapted to grow under osmotic stress synthesize and accumulate a 26 kilodalton protein (osmotin) which can constitute as much as 12% of total cellular protein. In cells adapted to NaCl, osmotin occurs in two forms: an aqueous soluble form (osmotin-I) and a detergent soluble form (osmotin II) in the approximate ratio of 2:3. Osmotin-I has been purified to electrophoretic homogeneity, and osmotin-II has been purified to 90% electrophoretic homogeneity. The N-terminal amino acid sequences of osmotins I and II are identical through position 22. Osmotin-II appears to be much more resistant to proteolysis than osmotin-I. However, it cross-reacts with polyclonal antibodies raised in rabbits against osmotin-I. Osmotin strongly resembles the sweet protein thaumatin in its molecular weight, amino acid composition, N-terminal sequence, and the presence of a signal peptide on the precursor protein. Thaumatin does not cross-react with antiosmotin. An osmotin solution could not be detected as sweet at a concentration at least 100 times that of thaumatin which could be detected as sweet. Immunocytochemical detection of osmotin revealed that osmotin is concentrated in dense inclusion bodies within the vacuole. Although antiosmotin did not label organelles, cell walls, or membranes, osmotin appeared sparsely distributed in the cytoplasm.

Green synthesis of carbon quantum dots from lemon peel waste: applications in sensing and photocatalysis

Abstract: In this work, water soluble carbon quantum dots (wsCQDs) were synthesized from lemon peel waste using a facile and cost effective hydrothermal process. As synthesized wsCQDs were 1–3 nm in size with spherical morphology and oxygen rich surface functionalities. These wsCQDs manifest excellent photoluminescence (PL) properties and exhibited quantum yield (QY) ∼14% with high aqueous stability. wsCQDs were further used to design an economic, green and highly sensitive fluorescent probe for the detection of Cr6+ ions with a detection limit of ∼73 nM. This wsCQDs based fluorescent probe could provide a simple, rapid, convenient technique for the sensitive and selective detection of Cr6+ in water purification processes. Further, wsCQDs were immobilized over electrospun TiO2 nanofibers and the photocatalytic activity for such a TiO2–wsCQDs composite was demonstrated using methylene blue (MB) dye as a model pollutant. Photocatalytic activity for the TiO2–wsCQDs composite was found to be ∼2.5 times more than that of TiO2 nanofibers. The synthesis method for wsCQDs could be easily scaled up for gram scale synthesis of carbon quantum dots.

Molecular Cloning of Osmotin and Regulation of Its Expression by ABA and Adaptation to Low Water Potential

Abstract: In response to adaptation to NaCl, cultured tobacco cells (Nicotiana tabacum L. cv Wisconsin 38) synthesize a major 26 kilodalton protein which has been named osmotin due to its induction by low water potentials. To help characterize the expression of osmotin in adapted cells, a cDNA clone for osmotin has been isolated. Abscisic acid induces messenger RNA encoding osmotin. Levels of this mRNA in adapted cells are approximately 15-fold higher than in unadapted cells. Message for osmotin is present at constant levels through the growth cycle of adapted cells, while in unadapted cells, the level decreases during exponential phase of growth and increases again when the cells approach stationary phase. While abscisic acid induces the message for osmotin, a low water potential environment appears to be required for accumulation of the protein. An osmotic shock to unadapted cells does not increase the amount of message or protein present most likely because this treatment does not induce immediately the accumulation of abscisic acid. The increased expression of osmotin in adapted cells is not correlated with an increase in osmotin gene copy number. Osmotin is homologous to a 24 kilodalton NaCl-induced protein in tomato, as well as thaumatin, maize α-amylase/trypsin inhibitor and a tobacco mosaic virus-induced pathogenesis-related protein.

Plant cellular and molecular responses to high salinity.

Abstract: ▪ Abstract Plant responses to salinity stress are reviewed with emphasis on molecular mechanisms of signal transduction and on the physiological consequences of altered gene expression that affect biochemical reactions downstream of stress sensing. We make extensive use of comparisons with model organisms, halophytic plants, and yeast, which provide a paradigm for many responses to salinity exhibited by stress-sensitive plants. Among biochemical responses, we emphasize osmolyte biosynthesis and function, water flux control, and membrane transport of ions for maintenance and re-establishment of homeostasis. The advances in understanding the effectiveness of stress responses, and distinctions between pathology and adaptive advantage, are increasingly based on transgenic plant and mutant analyses, in particular the analysis of Arabidopsis mutants defective in elements of stress signal transduction pathways. We summarize evidence for plant stress signaling systems, some of which have components analogous to t...

Structural models of primary cell walls in flowering plants: consistency of molecular structure with the physical properties of the walls during growth

Abstract: Advances in determination of polymer structure and in preservation of structure for electron microscopy provide the best view to date of how polysaccharides and structural proteins are organized into plant cell walls. The walls that form and partition dividing cells are modified chemically and structurally from the walls expanding to provide a cell with its functional form. In grasses, the chemical structure of the wall differs from that of all other flowering plant species that have been examined. Nevertheless, both types of wall must conform to the same physical laws. Cell expansion occurs via strictly regulated reorientation of each of the wall's components that first permits the wall to stretch in specific directions and then lock into final shape. This review integrates information on the chemical structure of individual polymers with data obtained from new techniques used to probe the arrangement of the polymers within the walls of individual cells. We provide structural models of two distinct types of walls in flowering plants consistent with the physical properties of the wall and its components.