Presented is a novel power management circuit for wireless sensor nodes that senses and processes a signal, and transmits an RF signal using scavenged energy without battery assistance. Experimental results show that with a single charging, it is possible for the sensor node to be activated by a wakeup pulse and deactivate itself after transmission of the RF signal to a receiver at a distance of 20 m every 5 min for 8 h without external power.Introduction: Advances in low-power electronic design and fabrication, along with the low duty cycle of wireless sensors, have reduced power requirements to the order of microwatts and promoted the possibility of microsensors and communication nodes that are powered by scavenged energy [1]. Since natural or artificial light and vibration is ubiquitous, solar cell and vibration-to-electricity converters seem to be the most appropriate power sources for the wireless ubiquitous sensor nodes [2][3][4]. To our knowledge, all currently reported wireless nodes powered by scavenged energy are activated when the storage capacitor charges to a certain pre-specified high energy level, and are deactivated when the stored energy has been depleted to a pre-specified low level [2,5,6]. However, owing to the existence of multiple sensor nodes and the energy being scavenged at random intervals in real-world applications, such random activation may cause signal collisions at the sink node. The deactivation process causes a much more serious problem, such that once the sensor node transmits the radio frequency (RF) signal, it cannot be activated again until the storage capacitor recharges. This means that, if the sensor node is powered by a solar cell, it does not operate at night. In this Letter we present a novel power management circuit that makes it possible to avoid data collision and to transmit multiple RF signals with a single charging, along with experimental results.
A bioassay-guided approach was employed to identify the glycolate oxidase (GOX, EC 1.1.3.15) inhibitory agent in a Tribulus terrestris L. extract using a microplate enzyme assay. This permitted the isolation of two flavonols quercetin (1) and kaempherol (2). Inhibition kinetics revealed quercetin (1) as non-competitive inhibitor of GOX with K m 2.5 mM and K i 1.8 mM, whereas kaempherol (2) showed competitive inhibition with K m 4-20 mM and K i 0.5 mM. Molecular docking studies were performed on spinach GOX with PDB entry 1al7 using BioMed CAChe software (v 6.1.1). The docking studies revealed significant dock score of the flavonols 1 and 2, i.e. −41.122 and −42.735 kcal/mol, respectively, in comparison with the known ligand to this enzyme HST -[4-Carboxy-5-(1-Pentyl) Hexylsulfanyl-1, 2, 3-Triazole] −44.643 kcal/mol. High protein sequence similarities and ligand binding specificities of the enzyme 1al7 from spinach and 2rdt from human encouraged us to extrapolate the results obtained with spinach GO to that of human GO enzyme. From this study it is concluded that kaempherol is a potential agent for optimization in effective management of urolithiasis in near future.Including a plant cell suspension culture first involves transferring the callus into liquid media. However, there are no objective criteria for selecting the location of the callus to be transferred. In this study, the inner and outer cells of Catharanthus roseus with various elicitors in solid-state cultures were differentiated by 1H NMR (nuclear magnetic resonance) spectrometry and principalcomponents analysis (PCA), with the aim of selecting high-yield cell lines. It was found that the samples of various elicitors and relative locations could be separated in PCA-derived score plots. Especially, there was a clear separation between nontreated samples and those cotreated with silver nitrate and methyl jasmonate. Loading-plot analysis was therefore applied to data obtained from nontreated samples and those cotreated with silver nitrate and methyl jasmonate to investigate the separation of major metabolites on score plots. The levels of valine, lactic acid/threonine, alanine, arginine, acetic acid, malic acid, succinic acid, citric acid, asparagine, choline, fumaric acid, phenylalanine, tryptophan, and formic acid were higher in the inner callus than in the outer callus, whereas glutamic acid, 2-oxoglutaric acid, oxalacetic acid, malonic acid, sucrose, lactose, and glucose dominated in the outer callus. The results obtained in this study suggest that inner and outer calli can be differentiated by 1H NMR-based metabolomic analysis, which also supplies basic information for selecting of adequate calli for use in suspension culture systems.For several years the main interest of our group is a cucumber (Cucumis sativus var. Borschagowski) chloroplast genome. Recently we have attempted to characterize plastosome expression using tiling microarray and to detect its response to chemically induced light stress. To induce the stress response we have used the ele...
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