Electrocatalytic oxidation of guanine and DNA on a carbon paste electrode modified by cobalt hexacyanoferrate films

The electrochemical behavior of cobalt hexacyanoferrate complex adsorbed on a carbon paste electrode (CPE) and its application to the electrocatalytic oxidation of guanine and single-strand DNA (ss-DNA) in aqueous solution are investigated in this report. The modification of CPE by the adsorption of this complex results in excellent amplification of the guanine oxidation response of ss-DNA. The effects of paste composition, scan rate, DNA, and guanine concentration were studied. The detection limits of 52 and 920 ng mL(-)(1) were obtained for guanine and ss-DNA, respectively.     

ISEFF: An ID-Based Scalable and EFficient Distributed File Sharing Technique in Vehicular Ad Hoc Networks

Using new wireless capabilities in vehicles, various applications have appeared in Vehicular Ad Hoc Networks (VANETs). Multimedia data sharing is one of these applications, which has recently been given so much attention. Most of presented schemes in this field have focused on direct opportunistic meetings between vehicles or request/response broadcast in the whole network, which are inefficient and un-scalable due to VANET characteristics. In this paper, we propose an ID-based Scalable and EFficient distributed File sharing technique that increases efficiency and scalability via taking advantages of BitTorrent protocol and consistent hashing technique. The results of simulations show that our approach increases the received file ratio, reduces total download time of files and message overhead. Consequently, it can enhance efficiency and performance.     

Hardware design of a new genetic based disk scheduling method

Disk management is an increasingly important aspect of operating systems research and development because it has great effect on system performance. As the gap between processor and disk performance continues to increase in modern systems, access to mass storage is a common bottleneck that ultimately limits overall system performance. In this paper, we propose hardware architecture of a new genetic based real-time disk scheduling method. Also, to have a precise simulation, a neural network is proposed to simulate seek-time of disks. Simulation results showed the hardware implementation of proposed algorithm outperformed software implementation in term of execution time, and other related works in terms of number of tasks that miss deadlines and average seeks.     

Recent advancement on estimation of blue carbon biomass using satellite-based approach

History revealed that people had been discharging a large proportion of carbon into the atmosphere through fossil fuel consumption and the marine environment. These have prompted atmospheric carbon fixations that have proved to be larger than at any other point throughout the human survival. Due to the critical role of blue carbon in the ocean carbon cycle, it is essential to pay extra attention to these habitats (mangrove, seagrass meadows, salt marshes, and coral reefs). Hence, this article reviews the recent developments in blue carbon biomass estimation using a geospatial approach and highlighted the blue carbon components achievements and gaps. Biomass and soil carbon estimation, using change detection analysis, were reviewed. Analysis of the carbon conversion factors, used in converting biomass to carbon, was demonstrated. The review shall act as support for the realization of the target 14.2 and 14.5 of the 14^th sustainable development goal established by the United Nations, to fast track the achievement of the 2020 agenda.     

Carbon nanotube composite coated platinum electrode for detection of Ga(III)

This study demonstrates the application of composite multi-walled carbon nanotube (MWCNT) polyvinylchloride (MWNT-PVC) based on 7-(2-hydroxy-5-methoxybenzyl)-5,6,7,8,9,10-hexahydro-2H benzo [b][1,4,7,10,13] dioxa triaza cyclopentadecine-3,11(4H,12H)-dione ionophore for gallium sensor. The sensor shows a good Nernstian slope of 19.68 ± 0.40 mV/decade in a wide linear range concentration of 7.9 × 10(-7) to 3.2 × 10(-2)M of Ga(NO(3))(3). The detection limit of this electrode is 5.2 × 10(-7)M of Ga(NO(3))(3). This proposed sensor is applicable in a pH range of 2.7-5.0. It has a short response time of about 10s and has a good selectivity over nineteen various metal ions. The practical analytical utility of this electrode is demonstrated by measurement of Ga(III) in river water.     

Reduction of Cr(VI) under acidic conditions by the facultative Fe(lll)-reducing bacterium Acidiphilium cryptum

The potential for biological reduction of Cr(VI) under acidic conditions was evaluated with the acidophilic, facultatively metal-reducing bacterium Acidiphilium cryptum strain JF-5 to explore the role of acidophilic microorganisms in the Cr cycle in low-pH environments. An anaerobic suspension of washed A. cryptum cells rapidly reduced 50 microM Cr(VI) at pH 3.2; biological reduction was detected from pH 1.7-4.7. The reduction product, confirmed by XANES analysis, was entirely Cr(III) that was associated predominantly with the cell biomass (70-80%) with the residual residing in the aqueous phase. Reduction of Cr(VI) showed a pH optimum similar to that for growth and was inhibited by 5 mM HgCl2, suggesting that the reaction was enzyme-mediated. Introduction of O2 into the reaction medium slowed the reduction rate only slightly, whereas soluble Fe(III) (as ferric sulfate) increased the rate dramatically, presumably by the shuttling of electrons from bioreduced Fe(II) to Cr(VI) in a coupled biotic-abiotic cycle. Starved cells could not reduce Cr(VI) when provided as sole electron acceptor, indicating that Cr(VI) reduction is not an energy-conserving process in A. cryptum. We speculate, rather, that Cr(VI) reduction is used here as a detoxification mechanism.