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Heavy metals persist in the sediment and can induce toxicological effects on living organisms. For analysing the risk of heavy metals, geochemical fractionation is beneficial. These geochemical fractions or speciations help to determine the heavy metals availability, mobility, toxicity, enrichment, and various risks. Here, we show how heavy metal contamination of sediment poses risks to both the ecosystem and human beings. We found significant Zn, Co and Cd contamination by analysing the geoaccumulation index. We also observed higher geoaccumulation index values for the pre-monsoon season than the post-monsoon one. Furthermore, pollution load index indicated gradual contamination of heavy metals in the sediments. This study's risk assessment and modified risk assessment codes showed low or no risk, but contamination factors indicated moderate to high risk. Our analysis of the effective range median mean quotient revealed some sampling stations as medium to high-priority sites. Similarly, probable effect level mean quotient designated some sampling stations as medium-low priority sites. We anticipated a moderate to significant mortality effect on the organisms from toxicity unit index values. Potential ecological risk index indicated a very high ecological risk on the Mahananda River. Furthermore, we predicted non-carcinogenic health hazards and carcinogenic health risks in the river's sediment. [ABSTRACT FROM AUTHOR]

Piezoelectric nanogenerators (PENGs) have been emerged as one of the most promising approach for harvesting energy from the movement of living system for low‐power electronic devices. Herein, a simple PENG and single‐electrode triboelectric nanogenerator (STENG) are reported that execute tremendous output performance. In zirconium oxide (ZrO2)/poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVDF‐HFP) nanocomposite polymer, ZrO2 acts as the nucleating agents for electroactive polymorph nucleation and also enhances the dielectric constant (≈23). Compared with previously reported PVDF‐HFP‐assisted prototype nanogenerators, this developed PENG exhibits excellent piezoelectric energy‐harvesting performance with very high power density, high energy conversion efficiency and high durability. The PENG exhibits a large value of open‐circuit voltage ≈120 V and short‐circuit current ≈1.95 μA under periodic finger imparting with high power density ≈7091 μW cm−3. Fabricated flexible PENG is capable to instantaneously light up commercially available 55 number of blue light emitting diode connected in parallel connection through bridge rectifier. High capacitor charging performance is also observed, such as 2.2 μF capacitor charged up to 3.5 V, in just 17 s time interval. Single‐electrode‐based TENG fabricated by this composite film also shows remarkable output voltage ≈7 V under finger touch. [ABSTRACT FROM AUTHOR]

Ten Darjeeling tea clones (BT15/263, RR17/144, B777, T253, B157, Sundaram, HV39, AV2, K1/1 and TTV1) were collected from the experimental garden of Darjeeling Tea Research and Development Centre, Kurseong. Total phenol, flavonoids and two antioxidating enzymes (peroxidase and superoxide dismutase) were estimated. The total phenol ranged between 241 and 28 GAE mg g of leaf dry weight. The highest amount obtained in four clones, B15/263 (241.47), RR17/144 (221.2), B777 (154.54) and B157 (140.23 mg g). Flavonoids were estimated as Catechin equivalent (CE) and ranged between 56.88 and 20.81 CE mg g leaf dry weight. Higher amounts occurred in BT15/263 (56.88 mg g), B777 (56.69) and RR17/144 (48.63). Antioxidant activities were measured following DPPH and ABTS free radicle scavenging procedures and the results were well according to total polyphenol content among the clones (in total phenols, ranges of correlation in DPPH assay were r = 0.990-0.989, p ≤ 0.05; in flavonoids r = 0.954, p ≤ 0.01-0.987, p ≤ 0.05). Similarly, ABTS percent scavenging results were quiet significant. The IC values were determined for both DPPH and ABTS assay. PAGE expressions of isoforms in two antioxidative enzymes and quantification of them also varied much among the investigated clones. The incidence of total phenols, flavonoids, PRX and SOD and ROS scavenging assay in in-situ condition, might be used as biochemical markers towards the superior adaptability against abiotic stress. In the present work, four clones (B15/263, B777, RR17/144 and B157) would be designated as comparatively better suited to the predicted abiotic stress. [ABSTRACT FROM AUTHOR]

The design of an energy-harvesting unit with superior output characteristics, i.e., high power density, is a great technological challenge in the present time. Here, simple, lightweight, flexible, and cost-effective piezoelectric nanogenerators (PENGs) have been fabricated by integrating the aluminum electrodes onto Er 3+ /Fe 3+ stimulated electroactive, visible-light-emitting, and large dielectric PVDF films in which ErCl 3 ·6H 2 O and Fe(NO 3 ) 3 ·9H 2 O act as the catalytic agents for electroactive β polymorph nucleation and the enhancement of dielectric properties. The developed PENGs exhibit excellent energy-harvesting performance with very high power density and very fast charging ability compared with the previously reported PVDF-assisted prototype nanogenerators. The PENGs lead to very large power density (∼160 and ∼55.34 mW cm -3 ) under periodic finger imparting for Er 3+ - and Fe 3+ -stimulated PVDF-film-based energy-harvester units, respectively. The fabricated self-powered PENG is also able to light up 54 commercially available light-emitting diodes.