Computer Aided Diagnosis of Melanoma Using Deep Neural Networks and Game Theory: Application on Dermoscopic Images of Skin Lesions

Early detection of melanoma remains a daily challenge due to the increasing number of cases and the lack of dermatologists. Thus, AI-assisted diagnosis is considered as a possible solution for this issue. Despite the great advances brought by deep learning and especially convolutional neural networks (CNNs), computer-aided diagnosis (CAD) systems are still not used in clinical practice. This may be explained by the dermatologist’s fear of being misled by a false negative and the assimilation of CNNs to a “black box”, making their decision process difficult to understand by a non-expert. Decision theory, especially game theory, is a potential solution as it focuses on identifying the best decision option that maximizes the decision-maker’s expected utility. This study presents a new framework for automated melanoma diagnosis. Pursuing the goal of improving the performance of existing systems, our approach also attempts to bring more transparency in the decision process. The proposed framework includes a multi-class CNN and six binary CNNs assimilated to players. The players’ strategies is to first cluster the pigmented lesions (melanoma, nevus, and benign keratosis), using the introduced method of evaluating the confidence of the predictions, into confidence level (confident, medium, uncertain). Then, a subset of players has the strategy to refine the diagnosis for difficult lesions with medium and uncertain prediction. We used EfficientNetB5 as the backbone of our networks and evaluated our approach on the public ISIC dataset consisting of 8917 lesions: melanoma (1113), nevi (6705) and benign keratosis (1099). The proposed framework achieved an area under the receiver operating curve (AUROC) of 0.93 for melanoma, 0.96 for nevus and 0.97 for benign keratosis. Furthermore, our approach outperformed existing methods in this task, improving the balanced accuracy (BACC) of the best compared method from 77% to 86%. These results suggest that our framework provides an effective and explainable decision-making strategy. This approach could help dermatologists in their clinical practice for patients with atypical and difficult-to-diagnose pigmented lesions. We also believe that our system could serve as a didactic tool for less experienced dermatologists.     

Controlled growth of silicon nanowires on silicon surfaces

This paper reports on silicon nanowire growth on oxidized silicon substrates using different approaches for gold catalyst deposition. The gold coated surfaces and the resulting nanowires were characterized using scanning electron microscopy. The gold catalysts were made up of gold nanoparticles (50 nm diameter), which were either dispersed or spotted at different concentrations using a robot, or were formed on a patterned Si/SiO₂ substrate by metal evaporation (63 nm diameter). The subsequent silicon nanowire growth was accomplished by CVD decomposition of silane gas (SiH₄) at high temperature (400–500^°C) in a vapor-liquid-solid (VLS) process. Under these conditions, a high density of silicon nanowires (SiNWs) was achieved on the oxidized silicon surfaces, but the distribution of the nanowires was found to be inhomogeneous in the case of the gold nanoparticles. Such result is attributed to the aggregation of the nanoparticles during the growth process. Alternatively, when gold nanodot catalysts were lithographically patterned on the surface, the nanowires were obtained in the patterned regions.     

First-principles calculations of ground-state and high-pressure phase of magnesium telluride

We study the ground-state properties of MgTe and the behavior under pressure using the new full potential augmented plane wave plus local orbital method (FP-LAPW + lo) within the local spin density approximation (LSDA) to density functional theory. The calculations were performed in the rocksalt (B1), cesium chloride (B2), zincblende (B3), wurtzite (B4) and nickel arsenide (B8₁) type structures. Our calculations clearly indicate that there is a structural transition from the B8 to B2, confirming recent experimental suggestions and also show that the ground-state phase of MgTe is the nickel arsenide (B8₁) structure.     

Polymer nanocomposites for microactuation and magneto-electric transduction

In the last decade, electroactive polymers have attracted much attention especially because of their very actuating capabilities. Large strain is experimentally observed, but under quite high electrical field, which can be a severe drawback for actuating applications. First part of the present paper is concerned with the reduction of applied field onto electroactive polymer films to get a given strain level. Polyurethane (PU) films filled with carbon black (CB) nanoparticles exhibit relatively high strain level under a field of only 12.5 kV/mm. The simple easy-tomake method solution cast method was applied. Even though the generated stress level is still quite low, the present work shows high strain level under quite low field appliance by easy manufacturing, lightweight, and flexible polymer film. Besides, another interest of the present paper is in magneto-elasto-electric effect of a polymer film filled with some magnetic nano particles. Films filled with nonpiezoelectric but with magnetite particles has still short history. With the use of magneto materials, a large magnetic DC bias field is generally required, and it causes big problem on application. The films filled with some magnetite nanoparticles (Fe3O4 and Nickel) are fabricated then examined. It is clearly demonstrated that our films do not require any DC bias. Although linear polarization value is relatively small, the first step of the studies on magnetite nano-filled film is presented.     

Gold island films on indium tin oxide for localized surface plasmon sensing

Mechanically, chemically and optically stable gold island films were prepared on indium tin oxide (ITO) substrates by direct thermal evaporation of thin gold films (2-6?nm) without the need for pre-?or post-coating. The effect of mild thermal annealing (150?°C, 12?h) or short high temperature annealing (500?°C, 1?min) on the morphology of the gold nanostructures was investigated. ITO covered with 2?nm gold nanoislands and annealed at 500?°C for 1?min was investigated for its ability to detect the adsorption of biotinylated bovine serum albumin using local surface plasmon resonance (LSPR), and its subsequent molecular recognition of avidin.     

Wettability Switching Techniques on Superhydrophobic Surfaces

The wetting properties of superhydrophobic surfaces have generated worldwide research interest. A water drop on these surfaces forms a nearly perfect spherical pearl. Superhydrophobic materials hold considerable promise for potential applications ranging from self cleaning surfaces, completely water impermeable textiles to low cost energy displacement of liquids in lab-on-chip devices. However, the dynamic modification of the liquid droplets behavior and in particular of their wetting properties on these surfaces is still a challenging issue. In this review, after a brief overview on superhydrophobic states definition, the techniques leading to the modification of wettability behavior on superhydrophobic surfaces under specific conditions: optical, magnetic, mechanical, chemical, thermal are discussed. Finally, a focus on electrowetting is made from historical phenomenon pointed out some decades ago on classical planar hydrophobic surfaces to recent breakthrough obtained on superhydrophobic surfaces.     

New Bacteriocins from Lacticaseibacillus paracasei CNCM I-5369 Adsorbed on Alginate Nanoparticles Are Very Active against Escherichia coli

Lacticaseibacillus paracasei CNCM I-5369, formerly Lactobacillus paracasei CNCM I-5369, produces bacteriocins that are remarkably active against Gram-negative bacteria, among which is the Escherichia coli-carrying mcr-1 gene that is involved in resistance to colistin. These bacteriocins present in the culture supernatant of the producing strain were extracted and semi-purified. The fraction containing these active bacteriocins was designated as E20. Further, E20 was loaded onto alginate nanoparticles (Alg NPs), leading to a highly active nano-antibiotics formulation named hereafter Alg NPs/E20. The amount of E20 adsorbed on the alginate nanoparticles was 12 wt.%, according to high-performance liquid chromatography (HPLC) analysis. The minimal inhibitory concentration (MIC) values obtained with E20 ranged from 250 to 2000 μg/mL, whilst those recorded for Alg NPs/E20 were comprised between 2 and 4 μg/mL, which allowed them to gain up to 500-fold in the anti-E. coli activity. The damages caused by E20 and/or Alg NPs/E20 on the cytology of the target bacteria were characterized by transmission electron microscopy (TEM) imaging and the quantification of intracellular proteins released following treatment of the target bacteria with these antimicrobials. Thus, loading these bacteriocins on Alg NPs appeared to improve their activity, and the resulting nano-antibiotics stand as a promising drug delivery system.     

Efficient elimination of environmental pollutants through sorption-reduction and photocatalytic degradation using nanomaterials

With the rapid development of industrial, large amounts of different inorganic and organic pollutants are released into the natural environments. The efficient elimination of environmental pollutants, i.e., photocatalytic degradation of persistent organic pollutants into nontoxic organic/inorganic chemicals, in-situ solidification or sorption-reduction of heavy metal ions, is crucial to protect the environment. Nanomaterials with large surface area, active sites and abundant functional groups could form strong surface complexes with different kinds of pollutants and thereby could efficiently eliminate the pollutants from the aqueous solutions. In this review, we mainly focused on the recent works about the synthesis of nanomaterials and their applications in the efficient elimination of different organic and inorganic pollutants from wastewater and discussed the interaction mechanism from batch experimental results, the advanced spectroscopy techniques and theoretical calculations. The adsorption and the photocatalytic reduction of organic pollutants and the sorption/reduction of heavy metal ions are generally considered as the main methods to decrease the concentration of pollutants in the natural environment. This review highlights a new way for the real applications of novel nanomaterials in environmental pollution management, especially for the undergraduate students to understand the recent works in the elimination of different kinds of inorganic and organic chemicals in the natural environmental pollution management.     

Characterization of the viscoelastic behavior of the pure bitumen grades 10/20 and 35/50 with macroindentation and finite element computation

In this article, we present an identification procedure that allows the determination of the viscoelasticity behavior of different grades of pure bitumen (bitumen 35/50 and bitumen 10/20). The procedure required in the first stage a mechanical response based on macroindentation experiments with a cylindrical indenter. A finite element simulation was performed in the second stage to compute the mechanical response corresponding to a viscoelasticity model described by three mechanical parameters. The comparison between the experimental and numerical responses showed a perfect matching. In addition, the identification procedure helped to discriminate between different bitumens characterized by different asphaltene and maltene contents. Finally, the developed procedure could be used as an efficient tool to characterize the mechanical behavior of the viscoelastic materials, thanks to the quantified relationship between the viscoleastic parameters and the force–penetration response. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3440–3450, 2013     

Comparison of different oxidation techniques on single-crystal and nanocrystalline diamond surfaces

Various oxidation techniques (plasma-beam, sulfo-chromic acid, UV-ozone, heating in air) were applied to single-crystalline (111) and (100) diamond surfaces as well as nanocrystalline diamond (NCD) films and analyzed by X-ray photoelectron spectroscopy (XPS) with respect to oxygen content and type of carbon–oxygen groups formed upon oxidation. Due to their increased surface, NCD films show a significantly higher oxygen uptake as compared to their single-crystal counterparts. No marked differences were observed between the different oxidation techniques. For all oxidation techniques used, several carbon–oxygen groups are simultaneously present on the surface. The relative fraction of singly-oxidized carbon atoms (attributed to isolated ether or epoxy-like groups) generally decreases slightly with increasing oxygen content, but always remains the dominating species.