Portulaca oleracea is globally used both as a vegetable and as an herb for medical and therapeutic purposes; hence the need to investigate its phytonutrients. The aim of this study was to evaluate the effects of different drying methods (hot-air drying, microwave drying and freeze-drying) on the color, phytochemicals content and antioxidant capacity of purslane leaves. The fresh purslane leaves had high contents of total phenolics (1447.59 mg GAE/ 100 g) and flavonoids (5011.87 mg QE/ 100 g) on dry weight basis. They exhibited high antioxidant capacity (53.23% and 147.78 μmol trolox/ 100 g) measured by DPPH and ABTS assay, respectively. Chromatic coordinates (L * , a * and b *) as well as total color difference (ΔE) were affected by drying methods. Drying methods caused a significant decrease in total phenolics, total flavonoids and antioxidant capacity of purslane leaves. Drying by hot-air at 50ºC and freezedrying had the lowest adverse effects on antioxidant capacities of purslane leaves while microwave drying cannot be a competitive process for preserving antioxidants and antioxidant capacity of purslane leaves. The changes in the antioxidant capacity due to the drying methods were positively correlated with the content of phenolics (R 2 = 0.9043-0.9885). Therefore, it can be suggested that special care should be taken when processing method is selected for the exploration of purslane leaves.
Behavioral responses of zebrafish larvae to environmental cues are important functional readouts that should be evoked on-demand and studied phenotypically in behavioral, genetical and developmental investigations. Very recently, it was shown that zebrafish larvae execute a voluntary and oriented movement toward the positive electrode of an electric field along a microchannel. Phenotypic characterization of this response was not feasible due to larva’s rapid movement along the channel. To overcome this challenge, a microfluidic device was introduced to partially immobilize the larva’s head while leaving its mid-body and tail unrestrained in a chamber to image motor behaviors in response to electric stimulation, hence achieving quantitative phenotyping of the electrically evoked movement in zebrafish larvae. The effect of electric current on the tail-beat frequency and response duration of 5–7 days postfertilization zebrafish larvae was studied. Investigations were also performed on zebrafish exposed to neurotoxin 6-hydroxydopamine and larvae carrying a pannexin1a (panx1a) gene knockout, as a proof of principle applications to demonstrate on-demand movement behavior screening in chemical and mutant assays. We demonstrated for the first time that 6-hydroxydopamine leads to electric response impairment, levodopa treatment rescues the response and panx1a is involved in the electrically evoked movement of zebrafish larvae. We envision that our technique is broadly applicable as a screening tool to quantitatively examine zebrafish larvae’s movements in response to physical and chemical stimulations in investigations of Parkinson’s and other neurodegenerative diseases, and as a tool to combine recent advances in genome engineering of model organisms to uncover the biology of electric response.
Ocean waves are one of the cleanest and most abundant energy sources on earth, and wave energy has the potential for future power generation. Triboelectric nanogenerator (TENG) technology has recently been proposed as a promising technology to harvest wave energy. In this paper, a theoretical study is performed on a duck-shaped TENG wave harvester recently introduced in our work. To enhance the design of the duck-shaped TENG wave harvester, the mechanical and electrical characteristics of the harvester's overall structure, as well as its inner configuration, are analyzed, respectively, under different wave conditions, to optimize parameters such as duck radius and mass. Furthermore, a comprehensive hybrid 3D model is introduced to quantify the performance of the TENG wave harvester. Finally, the influence of different TENG parameters is validated by comparing the performance of several existing TENG wave harvesters. This study can be applied as a guideline for enhancing the performance of TENG wave energy harvesters.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.