Influences of Mn doping on the microstructural,semiconducting, and optoelectronic properties of HgO nanostructure films

Mn-doped HgO nanostructured thin films (Hg_1-xMn_xO) have been prepared using electron beam evaporation technique on Corning glass (1022) substrate at room temperature with different concentrations x = 0, 0.015, 0.05, 0.1, 0.15, and 0.2. The microstructural, morphological, semiconducting, and optoelectronic properties of the films have been investigated. The X-ray diffraction spectra suggest a hexagonal wurtzite type structure with lattice parameters decreased with increasing Mn content. It was found that the average particle size of the films decreases with increasing Mn doping which is confirmed by FE-SEM and AFM micrographs. The optical band gap of the investigated Mn-doped HgO nanocrystalline films is determined from the absorption coefficient and found to increase with the increase of Mn concentration which is attributed to the sp-d exchange interaction and/or the quantum confinement effect. The refractive index and extinction coefficient of the Mn-doped HgO films are also reported. The refractive index dispersion n(λ) is analyzed by single-effective-oscillator dispersion model proposed by the Wemple–DiDomenico (WDD). The oscillator parameters were estimated. The obtained dispersion values are suitable for the design of optoelectronic devices.     

Mechanical properties of gamma‐irradiated styrene‐butadiene rubber/acid‐treated vermiculite clay/maleic anhydride nanocomposites

Nanoparticle vermiculite (VMT) clay was prepared by treatment with hydrochloric acid. Styrene‐butadiene rubber (SBR) nanocomposites were prepared by mixing different contents (2.5, 5, 7.5, and 10 phr) of untreated (VMT) and acid‐treated (DVMT) vermiculite clay, respectively. In addition, different contents (3, 7, and 10 phr) of maleic anhydride (MA) as compatibilizer were mixed via direct melt compounding in internal mixer. The effect of gamma irradiation, VMT clay, and MA contents on the mechanical properties was studied. The acid‐treated VMT clay was characterized by x‐ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier transform infrared (FT‐IR) spectroscopy. Meanwhile, the SBR/VMT composites, SBR/DVMT, and SBR/DVMT/MA nanocomposites were characterized via crosslinking density and tensile mechanical testing and FT‐IR spectroscopic analysis. The results indicated that good yield of nanoparticle vermiculite was achieved when the acid treatment was carried out for 120 h. In addition, the results showed that the presence of DVMT clay improved the chemical bonding in the SBR nanocomposites and hence their mechanical properties. The highest improvement was obtained when the contents of DVMT clay, MA, and irradiation dose were 10 phr, 3 phr, and 100 kGy, respectively. POLYM. ENG. SCI., 59:355–364, 2019. © 2018 Society of Plastics Engineers     

Highly Efficient and Water‐Insensitive Self‐Healing Elastomer for Wet and Underwater Electronics

Integrating self‐healing capabilities into soft electronic devices increases their durability and long‐term reliability. Although some advances have been made, the use of self‐healing electronics in wet and/or (under)water environments has proven to be quite challenging, and has not yet been fully realized. Herein, a new highly water insensitive self‐healing elastomer with high stretchability and mechanical strength that can reach 1100% and ≈6.5 MPa, respectively, is reported. The elastomer exhibits a high (>80%) self‐healing efficiency (after ≈ 24 h) in high humidity and/or different (under)water conditions without the assistance of an external physical and/or chemical triggers. Soft electronic devices made from this elastomer are shown to be highly robust and able to recover their electrical properties after damages in both ambient and aqueous conditions. Moreover, once operated in extreme wet or underwater conditions (e.g., salty sea water), the self‐healing capability leads to the elimination of significant electrical leakage that would be caused by structural damages. This highly efficient self‐healing elastomer can help extend the use of soft electronics outside of the laboratory and allow a wide variety of wet and submarine applications.     

Development of novel amisulpride-loaded solid self-nanoemulsifying tablets: preparation and pharmacokinetic evaluation in rabbits

Objective: The current investigation is focused on the formulation and in vivo evaluation of optimized solid self-nanoemulsifying drug delivery systems (S-SNEDDS) of amisulpride (AMS) for improving its oral dissolution and bioavailability.

Methods: Liquid SNEDDS (L-SNEDDS) composed of Capryol? 90 (oil), Cremophor^® RH40 (surfactant), and Transcutol^® HP (co-surfactant) were transformed to solid systems via physical adsorption onto magnesium aluminometasilicate (Neusilin US2). Micromeretic studies and solid-state characterization of formulated S-SNEDDS were carried out, followed by tableting, tablet evaluation, and pharmacokinetic studies in rabbits.

Results: Micromeretic properties and solid-state characterization proved satisfactory flow properties with AMS present in a completely amorphous state. Formulated self-nanoemulsifying tablets revealed significant improvement in AMS dissolution compared with either directly compressed or commercial AMS tablets. In vivo pharmacokinetic study in rabbits emphasized significant improvements in t_max, AUC_(0–12), and AUC_(0–∞) at p?<?.05 with 1.26-folds improvement in relative bioavailability from the optimized self-nanoemulsifying tablets compared with the commercial product.

Conclusions: S-SNEDDS can be a very useful approach for providing patient acceptable dosage forms with improved oral dissolution and biovailability.     

Training radial basis function networks using biogeography-based optimizer

Training artificial neural networks is considered as one of the most challenging machine learning problems. This is mainly due to the presence of a large number of solutions and changes in the search space for different datasets. Conventional training techniques mostly suffer from local optima stagnation and degraded convergence, which make them impractical for datasets with many features. The literature shows that stochastic population-based optimization techniques suit this problem better and are reliably alternative because of high local optima avoidance and flexibility. For the first time, this work proposes a new learning mechanism for radial basis function networks based on biogeography-based optimizer as one of the most well-regarded optimizers in the literature. To prove the efficacy of the proposed methodology, it is employed to solve 12 well-known datasets and compared to 11 current training algorithms including gradient-based and stochastic approaches. The paper considers changing the number of neurons and investigating the performance of algorithms on radial basis function networks with different number of parameters as well. A statistical test is also conducted to judge about the significance of the results. The results show that the biogeography-based optimizer trainer is able to substantially outperform the current training algorithms on all datasets in terms of classification accuracy, speed of convergence, and entrapment in local optima. In addition, the comparison of trainers on radial basis function networks with different neurons size reveal that the biogeography-based optimizer trainer is able to train radial basis function networks with different number of structural parameters effectively.

     

Early detection of Alzheimer’s disease based on the state-of-the-art deep learning approach: a comprehensive survey

Multimedia Tools and Applications - Alzheimer’s disease (AD) is a form of brain disorder that causes functions’ loss in a person’s daily activity. Due to the tremendous progress...     

Characterisation of manganese dioxides II. Kinetics of Interaction with Manganese (II) Ions in Aqueous Solution

The interaction between MnO₂ (I.C.S. No. 5), in the Na⁺ form and ⁵⁴Mn²⁺-labelled solution at pH 6 involves: a rapid process assumed to be Na⁺/Mn²⁺ ion-exchange and a slower process assumed to involve the exchange between Mn²⁺ ions in solution and Mn ions in a surface phase. The activation parameters ΔH^# and ΔS^# were found to be 52 and 83 kJ mol^?1 and ?130 and ?63 J mol^?1 for the two processes respectively. Exposing the solid to a flux of moderated neutrons had no effect on the rate of the second process. The exchange of Mn ions from the solid to the solution was demonstrated using ⁵⁶Mn-labelled solid and inactive Mn²⁺ solution. There was evidence of a still slower process.     

Separation of a compound effective against Biomphalaria alexandrina snails from the filtrate of Penicillium janthinellum

Biomphalaria alexandrina snails, as intermediate hosts of schistosomiasis, play a central role in dissemination of the disease. Control of these snails by chemical molluscicides adversely affects the aquatic environment, causing toxic and carcinogenic effects on non-target organisms. Searching for promising substances from biological origin becomes an urgent need to overcome these drawbacks. Screening tests were carried out on 236 fungal genera isolated from the habitat of freshwater snails in four Egyptian governorates. Twenty species were effective against B. alexandrina snails, but the most potent was Penicillium janthinellum as the value of LC₅₀ was 1.03%. Chemical analyses of this filtrate resulted in the separation of a compound effective against snails; it was identified as methyl gallate. Protein electrophoresis showed that both fungal filtrate and methyl gallate affect the protein pattern of snails’ haemolymph. Little or no mortality of Daphnia pulex individuals was observed after their exposure to sub lethal concentrations of each treatment.     

Effect of Nitrogen Alloying on Sulphur Behaviour during ESR of AISI M41 Steel

In this work, the effects of nitrogen alloying, physical properties and chemical composition of slag used in electro‐slag refining (ESR) on phosphorus and sulphur contents of AISI M41 high speed steel have been studied. The experiments were conducted with two high speed steel grades which were melted in an induction furnace (IF). The first grade is the standard AISI M41 high‐speed steel and the second one is nitrogen alloyed M41 (denoted M41N). The produced ingots were ESR remelted under three grades of calcium fluoride based slag. Results showed that the ESR process has no effect on the phosphorus content in steel but it is a good tool in removing sulphur. This study shows that a high desulphurization rate can be achieved by ESR process by optimizing slag properties where the viscosity and oxidation reactions play an important role in sulphur removal. Nitrogen alloying was found to retard sulphur removal.     

Improving the throwing power of acidic zinc sulfate electroplating baths

The effect of some plating parameters, such as Zn²⁺ ion concentration, pH, current density, temperature and duration on the throwing power, as well as on the throwing index of acidic zinc sulfate baths has been investigated. The addition of p‐anisidine (PA) and/or sodium dodecylbenzenesulfonate (DBS) has been examined as a possible means of improving the uniformity of deposit distribution. The additives cause a substantial increase in the overpotential for the reduction of Zn²⁺ ions and consequently improve the throwing power of the baths. The throwing power increases by a factor of four in the presence of DBS and a factor of one‐and‐a‐half in the presence of PA. The inhibition of zinc reduction was assumed to occur via adsorption of the PA or DBS molecules on the cathode surface and the adsorption followed the Langmuir adsorption isotherm. The surface morphology of the zinc plated with and without the additives was examined by using scanning electron microscopy (SEM). © 2000 Society of Chemical Industry