Electrochemical and structural evaluation of functionally graded bioglass-apatite composites electrophoretically deposited onto Ti6Al4V alloy

Titanium and its alloys are widely used as materials for implants, owing to their corrosion resistance, mechanical properties and excellent biocompatibility. However, clinical experience has shown that they are susceptible to localised corrosion in the human body causing the release of metal ions into the tissues surrounding the implants. Several incidences of clinical failures of such devices have demanded the application of biocompatible and corrosion resistant coatings and surface modification of the alloys. Coating metallic implants with bioactive materials is necessary to establish good interfacial bonds between the metal substrate and the bone. Hence, this work aimed at developing a bioglass-apatite (BG-HAP) graded coating on Ti6Al4V titanium alloy through electrophoretic deposition (EPD) technique. The coatings were characterized for their properties such as structural, electrochemical and mechanical stability. The electrochemical corrosion parameters such as corrosion potential (E_corr) (open circuit potential) and corrosion current density (I_corr) evaluated in simulated body fluid (SBF) have shown significant shifts towards noble direction for the graded bioglass-apatite coated specimens in comparison with uncoated Ti6Al4V alloy. Electrochemical impedance spectroscopic investigations revealed higher polarisation resistance and lower capacitance values for the coated specimens, evidencing the stable nature of the formed coatings. The results obtained in the present work demonstrate the suitability of the electrophoretic technique for the preparation of graded coating on Ti6Al4V substrates.     

Facile synthesis of the porous MnMo6S8 for highly stable pseudocapacitor

Transition metal sulfides are the prominent and leading materials for high-performance energy storage applications. Manganese molybdenum sulfide (MMS) is synthesized using facile hydrothermal method. The electrochemical active sites of the electrode material were enhanced by making the bi-metal sulfides with nanoporous diffusion channels in their crystal structure. The crystalline structure and morphology of the material were studied using X-ray diffraction pattern and high resolution-scanning electron microscope image, respectively. The functional groups present in the material were characterized using Fourier transform infrared spectrometer. MMS-coated nickel foam shows an excellent cycle stability. In 2 M KOH electrolyte, its specific capacity raised to 160% after 10,000 galvanostatic charge discharge (GCD) cycles at the current density of 10 A g^??1 and exhibited a higher specific capacity of 101.3 C g^??1 at 1 A g^??1. After 12,000 GCD cycles, the as-fabricated MMS//MMS symmetric device offers an elevated specific capacity of 228% from its initial value at the current density of 5 A g^??1.

     

Magnetization and Re LIII-Edge Studies of (Hg,Re)Sr2CuO4 + δ System

Chemically stable nominal compositions of (Hg_1-x Re _x )Sr₂CuO_{4 +} (x = 0.05, 0.10, and 0.20), designated as (Hg,Re)-1201 phase, were synthesized at 920°C in partial vacuum. The samples with x = 0.05 and 0.10 are superconducting (SC) with T _c ^onset 40 and 54 K, respectively. On the other hand, for the composition with x = 0.20, the sample is nonsuperconducting down to 5 K. The sample with composition (Hg_0.9Re_0.1)Sr₂CuO_{4 +} on cooling, below 10 K in dc-field of 4 kOe, shows a dramatic decrease (reversal) in diamagnetic signal. Such a reduction in diamagnetic response is also reflected by the sample's supercurrent induced magnetic hysteresis curve generated at 9 K. In the light of the available reports and our Re L_III-edge measurements, we attribute this effect to a field enhanced paramagnetic contribution probably arising mainly from mixed valent (6⁺, 7⁺ dominant) Re ions. The critical current density (J _c), calculated using Bean's model, for (Hg_0.9Re_0.1)Sr₂CuO_{4 +} is 6 × 10³ A/cm² (4.5 K, 5 kOe).     

Effective and efficient feature selection for large-scale data using Bayes’ theorem

This paper proposes one method of feature selection by using Bayes＇ theorem. The purpose of the proposed method is to reduce the computational complexity and increase the classification accuracy of the selected feature subsets. The dependence between two attributes （binary） is determined based on the probabilities of their joint values that contribute to positive and negative classification decisions. If opposing sets of attribute values do not lead to opposing classification decisions （zero probability）, then the two attributes are considered independent of each other, otherwise dependent, and one of them can be removed and thus the number of attributes is reduced. The process must be repeated on all combinations of attributes. The paper also evaluates the approach by comparing it with existing feature selection algorithms over 8 datasets from University of California, Irvine （UCI） machine learning databases. The proposed method shows better results in terms of number of selected features, classification accuracy, and running time than most existing algorithms.     

Improvement of Subthreshold Characteristics of Dopingless Tunnel FET Using Hetero Gate Dielectric Material: Analytical Modeling and Simulation

An improved subthreshold analytical model of Dual Material Double Gate Junctionless Tunnel FET (DMDG JLTFET) with stacked / hetero-dielectric gate oxide structure is proposed. The stacked gate oxide structure comprises of Silicon-dioxide (SiO₂) and Titanium Oxide (TiO₂). The high-K gate stack engineered device overcomes the Short Channel Effects (SCEs) caused by the ultrathin silicon devices. The subthreshold analysis is carried out by solving a two-dimensional Poisson’s equation using Parabolic approximation method. These characteristics are analyzed against various device parameters. Also, the impact of different high-K gate oxide materials with SiO₂ is also studied. A comparative analysis of short channel effects for DMDG TFET and DMDG JLTFET has been carried out. The results reveal that the proposed device provides better I_ON current, low leakage current and improved Transconductance-to-drain current ratio. Using TCAD Sentaurus device simulator, the subthreshold analytical model results have been simulated and verified with other TFET models.

     

Analytical Model of Double Gate Stacked Oxide Junctionless Transistor Considering Source/Drain Depletion Effects for CMOS Low Power Applications

This paper proposes a 2-D analytical model developed for Double Gate Junctionless Transistor with a SiO2/HfO2 stacked oxide structure. The model is solved     

Efficacy of bacteriophage LISTEXP100 combined with chemical antimicrobials in reducing Listeria monocytogenes in cooked turkey and roast beef

The aim of this study was to verify the effectiveness of the commercially available anti-Listeria phage preparation LISTEX^™P100 in reducing Listeria monocytogenes on ready-to-eat (RTE) roast beef and cooked turkey in the presence or absence of the chemical antimicrobials potassium lactate (PL) and sodium diacetate (SD). Sliced RTE meat cores at 4 and 10 °C were inoculated with cold-adapted L. monocytogenes to result in a surface contamination level of 10³ CFU/cm². LISTEX^TMP100 was applied at 10⁷ PFU/cm² and samples taken at regular time intervals during the RTE product's shelf life to enumerate viable L. monocytogenes. LISTEX^™P100 was effective during incubation at 4 °C with initial reductions of L. monocytogenes of 2.1 log₁₀ CFU/cm² and 1.7 log₁₀ CFU/cm², respectively, for cooked turkey and roast beef without chemical antimicrobials (there was no significant difference to the initial L. monocytogenes reductions in the presence of LISTEX^TMP100 for cooked turkey containing PL and roast beef containing SD-PL). In the samples containing no chemical antimicrobials, the presence of phage resulted in lower L. monocytogenes numbers, relative to the untreated control, of about 2 log CFU/cm² over a 28-day storage period at 4 °C. An initial L. monocytogenes cell reduction of 1.5 log₁₀ CFU/cm² and 1.7 log₁₀ CFU/cm², respectively, for cooked turkey and roast beef containing no chemical antimicrobials was achieved by the phage at 10 °C (abusive temperature). At this temperature, the L. monocytogenes cell numbers of samples treated with LISTEX™ P100 remained below those of the untreated control only during the first 14 days of the experiment for roast beef samples with and without antimicrobials. On day 28, the L. monocytogenes numbers on samples containing chemical antimicrobials and treated with LISTEX^TMP100 stored at 4 and 10 °C were 4.5 log₁₀ CFU/cm² and 7.5 log₁₀ CFU/cm², respectively, for cooked turkey, and 1.2 log₁₀ CFU/cm² and 7.2 log₁₀ CFU/cm², respectively, for roast beef. In both cooked turkey samples with and without chemical antimicrobials stored at 10 °C, the phage-treated samples had significantly lower numbers of L. monocytogenes when compared to the untreated controls throughout the 28-day storage period (P < 0.0001). For roast beef and cooked turkey containing chemical antimicrobials treated with LISTEX^TMP100 and stored at 4 °C, no more than a 2 log CFU/cm² increase of L. monocytogenes was observed throughout the stated shelf life of the product. This study shows that LISTEX^™P100 causes an initial reduction of L. monocytogenes numbers and can serve as an additional hurdle to enhance the safety of RTE meats when used in combination with chemical antimicrobials.     

On the Presence of Cu1+ in the Superconducting (Hg,M)Sr2CuO4+δ; M = Cr, Mo, or Re

The Cu K-edge measurements on the optimum T _c 1201 compounds (Hg_1?x M _x )Sr₂CuO_4+δ (M = Cr, Mo, or Re; 0.10 ≤ x ≤ 0.30) show besides Cu²⁺ (predominant) a very weak but distinct signature of Cu¹⁺, only in the superconducting (SC) samples. The Cu¹⁺ feature is conspicuously absent when these compositions are non-superconducting because of different processing conditions. Our finding of monovalent Cu in SC (Hg,M)/Sr-1201 favors the presence of Cu at the Hg-site and this seems to facilitate superconductivity in these cuprates.