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Cryptography is one of the major concerned areas of computer networks and data security. An efficient direction of providing data security can be termed as DNA based on cryptography. In this paper,...

Chemically induced dimerization (CID) systems, in which two proteins dimerize only in the presence of a small molecule ligand, offer versatile tools for small molecule sensing and actuation. However, only a handful of CID systems exist and creating one with the desired sensitivity and specificity for any given ligand is an unsolved problem. Here, we developed a combinatorial binders-enabled selection of CID (COMBINES-CID) method broadly applicable to different ligands. We demonstrated a proof-of-principle by generating nanobody-based heterodimerization systems induced by cannabidiol with high ligand selectivity. We applied the CID system to a sensitive sandwich enzyme-linked immunosorbent assay-like assay of cannabidiol in body fluids with a detection limit of ∼0.25 ng/mL. COMBINES-CID provides an efficient, cost-effective solution for expanding the biosensor toolkit for small molecule detection.

Compounds and composites with high dielectric performance are in high demand in electronic industry due to their ability to store more charge and lower energy dissipation. In this paper we present synthesis of flexible three phase nanocomposite films of graphene/titania/polydimethylsiloxane with reasonably high real part of permittivity and very low imaginary part of permittivity. Dielectric permittivity of polydimethylsiloxane was raised by addition of graphene and rutile titania used as conducting and ceramic additives, respectively added in various weight ratios. Dielectric studies of synthesized three phase graphene/titania/polydimethylsiloxane nanocomposite films with weight/weight of 2:15:20 exhibits dielectric permittivity of 34.8 even at very high frequency of 2 MHz. While loss tangent of the same three phase graphene/titania/polydimethylsiloxane nanocomposite film is as low as 0.01 and its AC conductivity is 4.3 × 10⁻⁵ Sm⁻¹. Complex impedance and complex electric modulus of three phase graphene/titania/polydimethylsiloxane nanocomposite films also confirm its capacitive behaviour. Based on these properties and results we propose that these type of three phase graphene/titania/polydimethylsiloxane nanocomposite films can be used as useful dielectric materials in energy storage devices. Refereed/Peer-reviewed

Recently, transition metal phosphates (TMPs) are demonstrated as promising candidates for supercapacitors due to their good conductivity and long-term stability. Herein, we have inrtoduced cobalt cyclotetraphosphate (Co2P4O12) as novel supercapacitive electrode material, which deliver a capacitance of 437 F/g with good stability over 3000 cycles (around 90%). To display the practical relevance, we have fabricated asymmetric device using activated carbon and Co2P4O12 as negative and positive electrodes, respecitvely, which can be operated up to 1.4 V. The introduction of redox-active moieties (such as potassium iodide (KI)) in parent KOH solution enhances the capacitance from 120 F/g to 156 F/g for Co2P4O12//AC cell with extended voltage window (1.8 V). Owing to the additional voltage and advancement in the capacitance, the cell delivers battery-level energy of 70 Wh/kg at power density of 2.3 kW/kg. It should be emphasized that even at high power (7.6 kW/kg), the cell maintained very good specific energy of 48 Wh/kg, suggesting excellent rate performance. The asymmetric device further showed long cycling stability with negligible loss and excellent Coulombic efficiency over 5000 cycles. Thus, metal cyclotetraphosphate can be employed as a promising electrode material in energy storage systems.

Graphene is extensively utilized in energy storage devices because of its high surface area and electronic conductivity as well as ease of electrode fabrication. But graphene sheets often stack themselves in polymeric matrices leading to poor capacitive performance. This problem was addressed herein by developing and inserting respectively two types of nano-sized conducting polymers into graphene interlayer spacing. The resulting hydrogel composite electrodes demonstrated efficient electron transfer for fast and reversible Faradaic reactions at the interface. Theoretical modelling by the density functional theory suggested that the reduction involve 2H + transfer steps from polyaniline to graphene oxide: the first step would be an epoxy-ring opening process after activation of the C-O bond, and the second step would be C-O rupture leading to a de-epoxidation process. This binder-free electrode demonstrated high cycling performance and ultrahigh volumetric capacitance of 612 F cm −3 , being 10 times higher than the activated carbon used in the current industry. The study represents a step forward towards the fabrication of flexible, high-energy density super capacitors. Refereed/Peer-reviewed

A new method based on scanning atmospheric plasma for an ultrafast reduction of graphene oxide (GO) and preparation of highly conductive graphene films and patterns is presented. This simple method is shown to provide a direct and scalable fabrication of graphene films on flexible and shaped substrates with a variety of patterns for broad applications. An effective and ultrafast (similar to 60 s) reduction of GO films into highly conductive graphene films at room temperature is demonstrated by this process that is impossible to achieve by conventional wet chemical and thermal reduction process. The software controlled x-y scanning unit allows fabrication of graphene films with variety of patterns on different substrates including glass, plastic, ceramics and metals with complex shapes required for flexible and wearable electronics and devices. Characterization results confirmed that a thin transparent graphene film can be produced with a surface sheets resistance of 22 k Omega/sq at the transparency of 88%, and a thick film (similar to 25 mu m) with a sheet resistance of 186 Omega/sq. A practical application of plasma fabricated graphene films was demonstrated for a supercapacitor devices able to deliver an outstanding volumetric capacitance of 536.55 F/cm(3) at a current density of 1 A/g. (C) 2017 Elsevier Ltd. All rights reserved. Refereed/Peer-reviewed

It remains a formidable challenge to develop supercapacitors having both high stretchability and electrochemical performance. A ternary polymer composite was herein developed by engineering graphene platelets (GnPs), poly (3,4-ethylenedioxythiophene) (PEDOT) and manganese dioxide (MnO2) into a kitchen sponge. Cost-effective GnPs having an electrical conductivity of 1460 S cm−1 were deposited onto the sponge pore surface by a simple dipping and drying process, followed by in situ polymerization of 3,4-ethylenedioxythiophene. MnO2 was then deposited onto the GnPs and PEDOT layers through soaking the GnP/PEDOT sponge into KMnO4 solution. When the composite was used as the electrodes for a flexible, stretchable supercapacitor, we obtained not only high specific capacitance but a high stretchability up to 400%. The supercapacitor demonstrated a specific capacitance of 802.99 F g−1 and an energy density of 55.76 Wh kg−1, with 99% capacitance retention over 1000 stretching cycles; these are attributed to the synergy between the composite components as well as the wavy device structure. The mass and thickness of the MnO2 layer was found to increase with the soak, leading to the enhancement of electrochemical performance of GnP/PEDOT/MnO2 sponge electrodes, i.e. 368.96 F g−1 for 5 min and 740.25 F g−1 for 10 min. Keywords: Graphene, Poly (3,4-ethylenedioxythiophene), Manganese oxide, Ternary composites, Stretchable supercapacitor

Refereed/Peer-reviewed In the present paper, synthesis and characterizations of flexible dielectric and ferroelectric polymer films combining different ratios of graphene, barium titanate and polydimethylsiloxane are presented. Broad range of characterization techniques were carried out to confirm their, morphological, structural, chemical, thermal and mechanical (flexibility, stretching, bending and twisting) characteristics. Dielectric studies showed that a high dielectric constant of the nanocomposite was dependent on the ratio of graphene:bariumtitanate:polydimethylsiloxane, showing that ratio of 15:25:100 had a high dielectric constant at high frequency range and the ratio 15:30:100 at the low frequency range. At 2 Hz the ratio 15:30:100 showed a dielectric constant of 116.9 which decreased to 30.6 at 2 MHz, thus showing capacitive nature at full frequency range. Meanwhile dielectric loss was very low i.e., 1.3 at 20 Hz and 0.02 at 2 MHz and AC conductivity was 1.6 × 10−7 S/m. Ferroelectric properties like energy density, energy loss and efficiency were calculated and compared. At an electric field of 0.92 kV/cm, remanant polarization and coercive field were 3.9 × 10−4 μC/cm2 and15.82 kV/cm, respectively. Energy density of 0.64 J/m3, energy loss 0.358 J/m3 and efficiency 64.2% were confirmed respectively. Results indicate that the nanocomposite films having desirable performances such as flexibility, thermal stability, high dielectric constant, high energy density are good candidates to be considered in energy storage and memory device applications.

The ladder graph plays an important role in many applications as Electronics, Electrical and Wireless communication areas. The aim of this work is to present a new class of odd graceful labeling for the ladder graph. In particular, we show that the ladder graph Ln with m-pendant Ln + mk1 is odd graceful. We also show that the subdivision of ladder graph Ln with m-pendant S(Ln) + mk1 is odd graceful. Finally, we prove that all the subdivision of triangular snakes (delt-k snake) with pendant edges S(delt-k snake)+ mk are odd graceful.

This paper presents a new and facile method to prepare molybdenum disulfide (MoS2)/graphene composites and their inks based on an improved ball milling process. The developed method is cost effective, environmentally friendly, and scalable, producing few-layer MoS2 material and MoS2/graphene-based inks. The prepared inks after characterization by SEM, Raman, XRD, FTIR, CA and rheology were used to fabricate electrodes for supercapacitors by adopting two designs: 2D printed and sandwiched electrodes. The electrodes showed excellent electrochemical performance with a specific capacitance of 392 Fg−1 at 5 mV s−1 and low equivalent resistance of 0.41 Ω, which outperforms the properties of graphene electrodes. The specific capacitance of electrodes prepared by 2D printing using MoS2/graphene ink was 76 Fg−1 at 5 mV s−1 with an areal capacitance of 58.5 mF/cm−2 at 0.77 mg/cm−2, demonstrating high energy storage capability. The performance of the MoS2/graphene composites and their inks highlights their promising application as electrode materials for high-performance energy storage devices.

Potassium (K) ion storage technology is recently receiving a great attention due to their low-cost and enormous abundance on the earth compared to lithium. However, the technology is still at a scientific research stage and exploring suitable electrode materials is a key challenge. Herein, we have engineered nitrogen doped carbon nanotubes (N-CNTs) as a promising anode material for K-ion storage through pyrolytic decomposition of polyaniline nanotubes (PAni-NTs). These N-CNTs delivers high reversible capacity with good rate performance and cycling stability. Taking advantage of these features, a potassium-ion hybrid capacitor (KIHC) is constructed using N-CNTs as battery-type anode and 3-dimensional (3D) laser scribed graphene (LSG) as capacitor-type cathode electrodes. The device displays a high energy density of 65 W h/kg, a high power output of 1000 W/kg, as well as a long cycling life (91% capacity retention over 5000 cycles). Thus, such an advanced energy storage system can satisfy the requirements of high power and high energy densities simultaneously in diverse applications at low-cost Refereed/Peer-reviewed

To address the limitations of piezoelectric polymers which have a low dielectric constant andto improve their dielectric and ferroelectric efficiency for energy storage applications, we designed and characterized a new hybrid composite that contains polyvinylidene fluoride as a dielectric polymer matrix combined with graphene platelets as a conductive and barium titanite as ceramic ferroelectric fillers. Different graphene/barium titanate/polyvinylidene fluoride nanocomposite films were synthesized by changing the concentration of graphene and barium titanate to explore the impact of each component and their potential synergetic effect on dielectric and ferroelectric properties of the composite. Results showed that with an increase in the barium titanate fraction, dielectric efficiency ofthe nanocomposite was improved. Among all synthesized nanocomposite films, graphene/barium titanate/polyvinylidene fluoride nanocomposite in the weight ratio of 0.15:0.5:1 exhibited thehighest dielectric constant of 199 at 40 Hz, i.e., 15 fold greater than that of neat polyvinylidene fluoride film at the same frequency, and possessed a low loss tangent of 0.6. However, AC conductivity and ferroelectric properties of graphene/barium titanate/polyvinylidene fluoride nanocomposite films were enhanced with an increase in the graphene weight fraction. Graphene/barium titanate/polyvinylidene fluoride nanocomposite films with a weight ratio of 0.2:0.1:1 possessed a high AC conductivity of 1.2 &times, 10&minus, 4 S/m at 40 Hz. While remanent polarization, coercive field, and loop area of the same sample were 0.9 &mu, C/cm2, 9.78 kV/cm, and 24.5 &mu, C/cm2&middot, V, respectively. Our results showed that a combination of graphene and ferroelectric ceramic additives are an excellent approach to significantly advance the performance of dielectric and ferroelectric properties of piezoelectric polymers for broad applications including energy storage.

A novel porous 3D-structured carbon composite material with a unique architecture by combining graphene and carbonized metal-organic framework (C-MOF) (HKUST-1) microrods for high performing supercapacitors has been synthesised and characterised. The HKUST-1 microrods were prepared by a new method, converting their diamond-like shape into microrods via mechanical shear mixing in an aqueous solution. Grinding of HKUST-1 and graphene oxide (GO) resulted in the formation of a 3D GO-MOF composite with intercalated HKUST-1 microrods between GO sheets. The composite film was treated by a laser scribing method and created a highly porous, a high surface area (>600 m²/g) and conductive 3D nanostructured composite film (L-rGO-C-MOF) used as electrodes for supercapacitor applications. The prepared film showed a high capacitance of 390 F/g at 5 mV/s, and a cyclic stability of 97.8% at 10 A/g after 5000 cycles. The symmetrical supercapacitor delivered an excellent power density of 8037.5 W/kg with an outstanding energy density of 22.3 Wh/kg confirming a new pathway to design new 3D porous graphene-MOF composites for high-performance energy storage devices. Refereed/Peer-reviewed

Layered double hydroxide (LDH) nanoparticles have tremendous anion-intercalating property. Co–Fe LDH has been synthesized using the ball milling method. Characterization of Co–Fe LDH was done by XRD, SEM, TEM and FT-IR. The prepared LDH was used, for the first time, as a catalyst for multi-walled carbon nanotubes (MWCNTs) via chemical vapor deposition (CVD) of acetylene at different temperatures (400–700 °C). Also, the ability of Co–Fe LDH as an adsorbent was investigated for the removal of Cd2+ ions from aqueous solutions. Various physicoechemical parameters such as pH, initial metal ion concentration, and time were studied. To get the adsorption isotherms, the concentrations of the metal ions ranging from 6 to 18 mg/l were used. The adsorption process follows pseudo-second-order reaction kinetics, as well as Langmuir adsorption isotherms. Interestingly, Co–Fe LDH demonstrated 95% Cd2+ removal at pH 9 and 6 h which could be applied in wastewater treatment characterized by a high efficiency and low cost. Refereed/Peer-reviewed

Polyaniline (PANi)/graphene nanocomposites have attracted tremendous interest because of their great potential in electrochemical energy storage applications, especially supercapacitors. We herein focus on the composite synthesis, device fabrication and particularly various techniques for the improvement of electrochemical performance. It is imperative to take close control of the interface in these nanostructured composites, which thus would lead to the desired synergistic effects and cyclic stability with the efficient diffusion of electrolyte ions and electrons. Challenges and perspectives are discussed for the development of highly efficient PANi/graphene electrodes for supercapacitors. Refereed/Peer-reviewed

This study deals with the use of a multivariate analysis method in order to understand the functioning of the Bizerte lagoon ecosystem. A set of hydrobiological parameters was collected during 10 monthly campaigns in 2004. A variant of the EOF (Empirical Orthogonal Function) technique is used to examine hydrobiological variability modes in this lagoon. The permanent features characterising the lagoon are obtained by applying the EOF technique to data after removing the annual cycle. Two major modes were obtained. The first one shows a contrast between the northern sector of the lagoon, influenced by the Mediterranean Sea, and the southern one influenced by continental waters. This mode is mostly prominent for temperature and salinity. The second mode shows a contrast between shallow waters along the coastal zones and the deep central area of the lagoon. This contrast is more pronounced towards the southwestern edge of the lagoon, a region of important freshwater input from the Tinja channel, which drifts towards the downstream area of Menzel Bourguiba. This second mode may also correspond to northward water circulation under southerly wind blowing frequently in summer. The spatial and temporal variability in the lagoon is highlighted by applying the EOF to the raw data without removing the annual cycle. A weight series is obtained for each variable by extracting the corresponding data and then projecting them on the corresponding eigenvector. Using this technique, only one mode was found dominant with more than 52% of the total variance. It was also found that the north-south contrast of temperature, salinity and phosphorous and the coast-centre contrast of Chlorophyll a are enhanced in summer. Other variables such as ammonia and nitrate also show significant annual cycles but with local patterns. (C) 2008 Elsevier Ltd. All rights reserved.

Three types of compressible, electrically conductive aerogels have been developed in this study usingpoly(3,4-ethylenedioxythiophene) - polystyrene sulfonate (PEDOT-PSS). The crosslinking between PEDOT-PSS and polyethylene oxide (PEO) promoted the formation of welded fibre-like morphology, which was explained through the purpose-designed experiment and characterization. Single-walled carbon nanotubes (SWCNTs) were added to further improve the electrical conductivity and thus the electrochemical performance. The PEDOT-PSS/PEO/SWCNT aerogel was used to fabricate a flexible supercapacitor which exhibited a specific capacitance of 362 F g1 at a scan rate of 20 mV s1; it demonstrated an energy density of 67.7 Wh kg1 and a power density of 13.5 kW kg1 at 100 mV s1 with 0e1.8 V potential window. When bent at 60, the supercapacitor exhibited 318 F g1 at 100 mV s1.The flexible supercapacitor showed a 94.6% retention after 5000 cycles at 5 A g1. Refereed/Peer-reviewed

International audience; An ecological model for the solar saltern of Sfax (Tunisia) was established and validated by comparing simulation results to observed data relative to horizontal distributions of temperature, nutrients and phytoplankton biomass. Sensitivity analysis was performed in order to assess the influence of the main ecological model parameters. First applied at the saltern's pond A1, the model was calibrated with field data measured over 4 years of study (from 2000 to 2003), which allowed an evaluation of parameters such as maximum growth rate of phytoplankton, optimal growth temperature and constant of half saturation for P/N assimilation by phytoplankton. Simulation results showed that the model allowed us to predict realistic phytoplankton variations of the study area, though we were unable to accurately reproduce the nutrient variation. The model was then applied to simulations of the impact of changes in phytoplankton biomass through scenarios such as hypothetic climate changes and saltern restoration.

Nokoué Lake is a complex ecosystem, the understanding of which requires control of physical processes that have occurred. For this, the Surface Water Modeling System (SMS) hydrodynamic model was calibrated and validated on the water depth data. The results of these simulations show a good match between the simulated and observed data for bottom roughness and turbulent exchange coefficients, of 0.02 m−1/3·s and 20 m2/s respectively. Once the ability of the model to simulate the hydrodynamics of the lake is testified, the model is used to simulate water surface elevation, exchanged flows and velocities. The simulation shows that the tidal amplitude is maximum at the inlet of the channel and decreases gradually from the inlet towards the lagoon’s main body. The propagation of the tidal wave is characterized by the dephasing and the flattening of the amplitude tide, which increases as we move away from the channel. This dephasing is characterized by a high and low tides delay of about 1 or 4 h and also depends on the tide amplitude and location. The velocities inside the lake are very low and do not exceed 0.03 m/s. The highest are obtained at the entrance of the channel. In a flood period, in contrast with the low-water period, incoming flows are higher than outflows, reinforced by the amplitude of the tide. An average renewal time of the lake has been estimated and corresponds during a flood period to 30 days for an average amplitude tide and 26.3 days on a high amplitude tide. In a low water period it is 40.2 days for an average amplitude tide and 30 days for a high amplitude tide. From the results obtained, several measures must be taken into account for the rational management of the lake water resources. These include a dam construction at the lake upstream, to control the river flows, and the dredging of the channel to facilitate exchanges with the sea.

International audience; The distribution of phytoplankton abundance, biomass and species composition coupled with environmental factors and metazooplankton was studied relatively intensively and over a period of four consecutive years in five ponds featuring a gradient of increasing salinity from near to that of sea water to a nine-fold concentration from 2000 to 2003. The results indicate that the physical characteristics of the water (temperature and salinity) were quite similar over the years. Nutrients, which were concentrated in pond A1, decreased with increases in salt concentration. The composition of the phytoplankton community showed strong seasonality. Diatoms dominated in the first ponds A1, A16 and C2-1, followed by dinoflagellates. Chlorophyceae dominated the phytoplankton community in the hypersaline ponds M2 and TS. Cyanobacteriae were relatively abundant in ponds M2 and TS. The highest phytoplankton density and biomass were found in the ponds with the highest salinity due to the proliferation of Dunaliella salina (Chlorophyta: Volvocales). The inter-annual study of phytoplankton succession in the Sfax solar salterns showed slight differences among the years of study due to the stability of the environmental conditions. Phytoplankton communities were permanently primitive, stage 1 e structured as they failed to build complexity because of salt stress which operates for longer and above any other variables. This reduced frequency of disturbance to the existing course of regulation, allowed the community to “mature” from its “primitive” state, rather than experience frequent structural setbacks.