Towards sustainable, solution-processed organic field-effect transistors using cashew gum as the gate dielectric

To realize low-cost, environmentally friendly electronic devices and circuits, there is currently a strong trend to explore plant-based dielectric materials because they can be responsibly sourced from agricultural or forest vegetation, are generally water-soluble, and possess good electrical insulator properties. In this contribution, organic field-effect transistors (OFETs) using a biopolymer dielectric obtained from exudates of Anacardium occidentale Linn. trees, namely, cashew gum (CG), are reported. To characterise the physical and dielectric properties of the gum, thin films and metal-insulator-metal (MIM) capacitors were prepared and characterized. To evaluate the material’s performance in OFETs, bottom-gate top-contact (BGTC) p-channel poly [3,6-di(2-thien-5-yl)-2,5-di(2-octyldodecyl)-pyrrolo (3,4-c)pyrrole-1,4-dione) thieno (3,2-b) thiophene]:polymethyl methacrylate (DPPTTT:PMMA) transistors were engineered and studied. The fabricated MIM capacitors display a comparatively high areal capacitance of 260 nF/cm2 at 1 kHz for 130 nm thick films. As a result, the solution-processed DPPTTT:PMMA OFETs favourably operate at 3 V with the average saturation field-effect mobility equal to 0.20 cm2/Vs., threshold voltage around −1.4 V, subthreshold swing in the region of 250 mV/dec, and ON/OFF current ratio well above 103. As such, cashew gum emerges as a promising dielectric for sustainable manufacturing of solution-processed organic FETs

Two level evolutionary algorithm for Capacitated Network Design Problem

Efficient design of networks topologies is challenging, especially with the arrival of the virtualization in these last years. In this paper, we deal with the Capacitated Network Design Problem (CNDP) with modular link capacities to design minimum cost network while satisfying the flow demands. We propose a two levels Genetic Algorithm (GA) based model that can deal with several variations of CNDP. Our proposition defines a new encoding scheme to treat the modular case. Extensive simulation results on Atlanta, France and Germany network instances show that the proposed algorithm is much more efficient than the Iterative Local Search algorithm

Solving the Capacitated Network Design Problem in Two Steps

In this paper, we propose a two steps-based algorithm to solve the modular link version of the Capacitated Network Design Problem (CNDP) which consists to determine the optimal network that guarantees the routing of a set of commodities. In our proposition, CNDP is divided into two sub-problems: Network Design problem (NDP) and Network Loading Problem (NLP). In the first step, we solved NDP by using the genetic algorithms which select sets of network topologies. In the second step, NLP is solved with the use of Linear programming to evaluate and validate the best network topologies. Simulation results on three real network instances (Atlanta, France and Germany) show that the proposed algorithm is better and more efficient than the Iterative Local Search algorithm

Genetic algorithm based model for capacitated network design problem

Efficient design of networks topologies is challenging, especially with the arrival of the virtualization in these last years. In this paper, we deal with the Capacitated Network Design Problem (CNDP) with modular link capacities to design minimum cost network while satisfying the flow demands. We propose a two levels Genetic Algorithm (GA) based model that can deal with several variations of CNDP. Our proposition defines a new encoding scheme to treat the modular case. Extensive simulation results on Atlanta, France and Germany network instances show that the proposed algorithm is much more efficient than the Iterative Local Search algorithm

Oncocytoma with a vascular extension, associated with a papillary carcinoma: A case report

This is a case report about a patient which presents with two right renal tumors, one of them being an oncocytoma with typical histopathological features and renal vein extension. Recent studies show that despite renal vein thrombus being a histological sign of malignancy; when associated with renal oncocytoma, it should not alter the benign prognosis of oncocytoma, and a simple follow-up may be carried. Further explorations should be done when easily available, and when the histopathologic diagnosis of oncocytoma is uncertain, to rule out the differential diagnosis of a chromophobe renal cell carcinoma, oncocytic variant

A Decade of Improvements in Mimiviridae and Marseilleviridae Isolation from Amoeba

International audienceSince the isolation of the first giant virus, the Mimivirus, by T.J. Rowbotham in a cooling tower in Bradford, UK, and after its characterisation by our group in 2003, we have continued to develop novel strategies to isolate additional strains. By first focusing on cooling towers using our original time-consuming procedure, we were able to isolate a new lineage of giant virus called Marseillevirus and a new Mimivirus strain called Mamavirus. In the following years, we have accumulated the world's largest unique collection of giant viruses by improving the use of antibiotic combinations to avoid bacterial contamination of amoeba, developing strategies of preliminary screening of samples by molecular methods, and using a high-throughput isolation method developed by our group. Based on the inoculation of nearly 7,000 samples, our collection currently contains 43 strains of Mimiviridae (14 in lineage A, 6 in lineage B, and 23 in lineage C) and 17 strains of Marseilleviridae isolated from various environments, including 3 of human origin. This study details the procedures used to build this collection and paves the way for the high-throughput isolation of new isolates to improve the record of giant virus distribution in the environment and the determination of their pangenome

Khaya gum – a natural and eco-friendly biopolymer dielectric for low-cost organic field-effect transistors (OFETs)

Nature provides a wide range of dielectric biopolymers that can be used in electronic devices. In this work, organic field-effect transistors (OFETs) using khaya gum (KG), a natural, biodegradable biopolymer that can be directly collected from khaya senegalensis trees, as the gate dielectric are demonstrated. The fabricated bottom gate/top contact poly (3,6-di (2-thien-5-yl)-2,5-di (2-octyldodecyl)-pyrrolo [3,4-c] pyrrole-1,4-dione) thieno [3,2-b] thiophene) (DPPTTT) –(polymethylmethacrylate) (PMMA) OFETs operate at 3 V with a saturation field-effect mobility (μsat) 0.3 cm2V−1 s−1, threshold voltage (Vth) -1.3 V, subthreshold swing (SS) 450 mV/dec, and current on/off ratios (ION/OFF) larger than 3 × 103. Significantly, the gate leakage current (IG) does not exceed 10–8 A for the gate-source voltage (VGS) ≤-3 V. UV–Vis spectra analysis shows that the prepared khaya gum films exhibit low absorbance and high transparency (up to 90%) with a calculated optical band gap of about 4.3 eV. Thermal characterization shows two stages of decomposition and a glass transition at around 60 °C. Characterization of metal–insulator-metal (MIM) capacitors using khaya gum reveals that the KG-based MIM capacitors possess a relatively high capacitance per unit area (Ci) of 130 ± 3 nF/cm2 at 1 kHz. As a result, khaya gum emerges as the dielectric of choice for low voltage, transparent OFETs where environmentally friendly device manufacturing is required

Immediate and durable effects of maternal tobacco consumption alter placental DNA methylation in enhancer and imprinted gene-containing regions

International audienceBackground: Although exposure to cigarette smoking during pregnancy has been associated with alterations of DNA methylation in the cord blood or placental cells, whether such exposure before pregnancy could induce epigenetic alterations in the placenta of former smokers has never been investigated. Methods: Our approach combined the analysis of placenta epigenomic (ENCODE) data with newly generated DNA methylation data obtained from 568 pregnant women, the largest cohort to date, either actively smoking during their pregnancy or formerly exposed to tobacco smoking. Results: This strategy resulted in several major findings. First, among the 203 differentially methylated regions (DMRs) identified by the epigenome-wide association study, 152 showed "reversible" alterations of DNA methylation, only present in the placenta of current smokers, whereas 26 were also found altered in former smokers, whose placenta had not been exposed directly to cigarette smoking. Although the absolute methylation changes were smaller than those observed in other contexts, such as in some congenital diseases, the observed alterations were consistent within each DMR. This observation was further supported by a demethylation of LINE-1 sequences in the placentas of both current (beta-coefficient (β) (95% confidence interval (CI)), − 0.004 (− 0.008; 0.001)) and former smokers (β (95% CI), − 0.006 (− 0.011; − 0.001)) compared to nonsmokers. Second, the 203 DMRs were enriched in epigenetic marks corresponding to enhancer regions, including monomethylation of lysine 4 and acetylation of lysine 27 of histone H3 (respectively H3K4me1 and H3K27ac). Third, smoking-associated DMRs were also found near and/or overlapping 10 imprinted genes containing regions (corresponding to 16 genes), notably including the NNAT, SGCE/PEG10, and H19/MIR675 loci