Adaptive neuro‐fuzzy inference system and artificial neural network modeling of proton exchange membrane fuel cells based on nanocomposite and recast Nafion membranes

In this study, a proton exchange membrane fuel cell (PEMFC) is modeled by multilayer perceptron neural network (MLPNN), RBF neural network (RBFNN), and adaptive neuro‐fuzzy inference system (ANFIS). Experimental data are obtained on the basis of the fabricated membrane‐electrode assembly (MEA) responses using prepared nanocomposite and recast Nafion membranes in the PEMFC. Four parameters including cell temperature, inlet gas temperature, current density, and inorganic additive percent are used as inputs, and the cell voltage is considered as the output. The results show that there is no considerable discrepancy between the RBFNN accuracy (R = 0.99554) and the MLPNN accuracy (R = 0.99609) for the performance prediction. The required time for developing the RBFNN model is significantly lower than the MLPNN model. A variety of ANFIS structure is explored to approximate the behavior of the system. The effect of cell and inlet gas temperatures on the PEMFC performance is investigated by the ANFIS developed model. Predicted polarization and power–current behavior by the ANFIS for the MEA prepared by the recast Nafion and the nanocomposite membranes at the cell temperatures 50 °C to110°C are in high agreement with the experimental data. Predicted data by the ANFIS show that because of the property of Cs_2.5H_0.5PW₁₂O₄₀ additive for retaining water, much higher current density and power density at the same voltage are achieved for the nanocomposite membrane compared with the recast Nafion membrane in the PEMFC. Copyright © 2011 John Wiley & Sons, Ltd.     

Modeling and Docking Studies on Novel Mutants (K71L and T204V) of the ATPase Domain of Human Heat Shock 70 kDa Protein 1

The purpose of exploring protein interactions between human adenovirus and heat shock protein 70 is to exploit a potentially synergistic interaction to enhance anti-tumoral efficacy and decrease toxicity in cancer treatment. However, the protein interaction of Hsp70 with E1A32 kDa of human adenovirus serotype 5 remains to be elucidated. In this study, two residues of ATPase domain of human heat shock 70 kDa protein 1 (PDB: 1 HJO) were mutated. 3D mutant models (K71L and T204V) using PyMol software were then constructed. The structures were evaluated by PROCHECK, ProQ, ERRAT, Verify 3D and ProSA modules. All evidence suggests that all protein models are acceptable and of good quality. The E1A32 kDa motif was retrieved from UniProt ({"type":"entrez-protein","attrs":{"text":"P03255","term_id":"119020","term_text":"P03255"}}P03255), as well as subjected to docking interaction with NBD, K71L and T204V, using the Autodock 4.2 program. The best lowest binding energy value of −9.09 kcal/mol was selected for novel T204V. Moreover, the protein-ligand complex structures were validated by RMSD, RMSF, hydrogen bonds and salt bridge analysis. This revealed that the T204V-E1A32 kDa motif complex was the most stable among all three complex structures. This study provides information about the interaction between Hsp70 and the E1A32 kDa motif, which emphasizes future perspectives to design rational drugs and vaccines in cancer therapy.     

A low-complexity adaptive beamformer for ultrasound imaging using structured covariance matrix

In recent years, adaptive beamforming methods have been successfully applied to medical ultrasound imaging, resulting in simultaneous improvement in imaging resolution and contrast. These improvements have been achieved at the expense of higher computational complexity, with respect to the conventional non-adaptive delay-and-sum (DAS) beamformer, in which computational complexity is proportional to the number of elements, O(M). The computational overhead results from the covariance matrix inversion needed for computation of the adaptive weights, the complexity of which is cubic with the subarray size, O(L(3)). This is a computationally intensive procedure, which makes the implementation of adaptive beamformers less attractive in spite of their advantages. Considering that, in medical ultrasound applications, most of the energy is scattered from angles close to the steering angle, assuming spatial stationarity is a good approximation, allowing us to assume the Toeplitz structure for the estimated covariance matrix. Based on this idea, in this paper, we have applied the Toeplitz structure to the spatially smoothed covariance matrix by averaging the entries along all subdiagonals. Because the inverse of the resulting Toeplitz covariance matrix can be computed in O(L(2)) operations, this technique results in a greatly reduced computational complexity. By using simulated and experimental RF data-point targets as well as cyst phantoms-we show that the proposed low-complexity adaptive beamformer significantly outperforms the DAS and its performance is comparable to that of the minimum variance beamformer, with reduced computational complexity.     

Synthesis and Characterization of Polycarbonate/TiO2 Ultrafiltration Membranes: Critical Flux Determination

A novel polycarbonate (PC) membrane was modified with titanium dioxide via nonsolvent-induced phase separation method to improve its hydrophilicity and antifouling properties in a submerged membrane system for the removal of humic acid (HA) both with and without polyaluminum chloride (PAC) coagulant. The effect of TiO₂ additive on the morphology and performance of the nanocomposite membranes was studied by atomic force microscopy, field emission scanning electron microscopy, energy dispersive X-ray, mechanical properties, water contact angle, porosity, pure water flux, rejection tests, and antifouling parameters. The obtained results revealed that a higher critical flux was achieved by the PC/TiO₂ nanocomposite membrane. The flux recovery ratio of the neat PC membrane increased with the addition of TiO₂ nanoparticles and without PAC coagulant. HA removal for the PC nanocomposite membrane was higher than that of the neat PC membrane with and without PAC coagulant.     

Degradation of the antimicrobial triclocarban (TCC) with ozone

Triclocarban (TCC) has been used as an antimicrobial compound for many decades due to its sanitising properties. Recent studies showed that TCC is toxic and causes disruption to the endocrine system. In this work, ozone oxidation of TCC was studied in 70% acetonitrile:30% water solutions. Ozone degraded TCC effectively and the reaction rates increased substantially with ozone gas concentration, pH and temperature. Second-order-reaction kinetics was suitable to describe the chemical reaction. The effect of temperature was described by the Arrhenius equation and the activation energy was found equal to 31.0 kJ/mol. The stoichiometry of the reaction was one and the value of the rate constant at pH 7 was 5 × 10³ M⁻¹ s⁻¹.     

Microwave synthesis and spectroscopic studies of some complex compounds as pigments and their applications in paints

Metal complex pigments have been widely used for various applications such as pigments in coatings. This work presents the use of microwave technique (Green chemistry) for the synthesis of new copper(II), nickel(II), iron(III), and chromium(III) Schiff base complexes derived from metal salts and Schiff base ligand. Also, the microwave technique was used in the synthesis of Schiff base ligand which is derived from selected amine, namely methoxy-tolidine, and selected aldehyde, namely 2-hydroxynaphthaldehyde. The prepared ligand and metal complex pigments were characterized by elemental analysis, NMR, spectral UV–Vis, infrared, and thermal gravimetric analysis. The physical and mechanical properties and corrosion resistance of dry paint films were also examined. The obtained results revealed that the prepared metal complex pigments showed excellent mechanical and corrosion resistance.     

The effect of TiO2 additive on sinterability and properties of SiC-Al2O3-Y2O3 composite system

In the current research, the effects of TiO₂ additive on mechanical and physical properties of SiC bodies, sintered by liquid phase methods were investigated. Al₂O₃ and Y₂O₃ were used as sintering-aids (10?wt% in total) with an Al₂O₃/Y₂O₃ ratio of 43/57 to provide liquid phase during Sintering. TiO₂ was also used as the oxide additive with an amount ranging from 0 to 10?wt%. After scaling and mixing the starting materials by a planetary mill, the obtained slurry was dried at 100?℃ for four hours. The derived powders were finally pressed under a pressure of 90?MPa. The samples were then pyrolyzed and sintered at 600?℃ and 1900?℃, respectively under argon atmosphere for 1.5?h. Phase analysis showed no trace of TiO₂ after the sintering process, demonstrating the complete TiO₂ to TiC transformation. The results showed that an increase in TiO₂ content up to 5?wt%, led an improvement in all the measured properties including the relative density, hardness, Young's modulus, bending strength, indentation fracture resistance and the brittleness factor, reaching to 96.2%, 24.4?GPa, 395.8?GPa, 521?MPa, 5.8?MPa?m^1/2 and 286.5?×?10^?6 m^?1, respectively. However more than 5?wt% additive resulted in a decrease in all the above-mentioned properties. Microstructural studies demonstrated that crack deflection and crack bridging were the major mechanisms responsible for an increase in the indentation fracture resistance.     

ZnO quantum dot based thin films as promising electron transport layer: Influence of surface-to-volume ratio on the photoelectric properties

ZnO quantum dots (QDs) with average particle size of 4.4 nm were prepared using a low temperature processing solvothermal route. ZnO QD based thin films were then prepared from the ZnO QD based solution using spin coating technique and annealed at 250, 350 and 450 °C. The average grain size and energy band gap of ZnO were respectively increased and decreased from 5.5 to 22.9 nm and 3.37 to 3.27 eV upon increasing the annealing temperature up to 450 °C. The photoluminescence analysis showed that the as-coated ZnO film and ZnO film annealed at 250 °C have high density of oxygen vacancies; these defects were reduced upon increasing the temperature to 350 and 450 °C. The photoelectric properties of the films were strongly affected by the grain size and the defects present in the films. The photo-to-dark current ratio (PDCR) was decreased from 3723 to 371%, whereas the responsivity was increased from 1.25 to 218 mA/W with the increase of temperature to 450 °C. As-coated and 250 °C-annealed films exhibited better photoresponse than others in terms of PDCR, rise time and fall time due to their larger surface-to-volume ratio, making them promising candidate as electron transport layer in perovskite solar cells.     

PEG‐Citrate dendrimer second generation: is this a good carrier for imaging agents In Vitro and In Vivo ?

While cancer is the leading cause of human''s deaths worldwide, finding an imaging agent which can detect cancer tumours is needed for cancer diagnosis. In the present study, PEG‐citrate dendrimer‐G₂ was used as a nano‐carrier of FITC dye and Iohexol to help passive targeting and uptake of both imaging agents in cancer cells/tumour in vitro and in vivo. Dendrimer was synthesisedand the product characterised using LC‐MS, FT‐IR, DLS, ELS, AFM, and ¹ HNMR. After FITC loading into dendrimer, MTT was performed to determine the cytotoxicity of formulation on HEK‐293 and MCF‐7 cells. In vitro imaging using dendrimer‐FITC was done via fluorescent microscope thereafter. Moreover, CT imaging using Iohexol was employed to show the targeting nature and ability of the complex to use as imaging agent in vivo. Data yielded in this study corroborate the notion that the promised dendrimer was synthesised properly and had no toxicity along with FITC on normal cell. Furthermore, CT and fluorescent images showed the targeting nature and imaging ability of Iohexol/FITC loaded dendrimer in vitro and in vivo. Overall, results showed promising characteristics of the novel complexes using dendrimer‐G₂ both in vitro and in vivo.Inspec keywords: drug delivery systems, cellular biophysics, molecular biophysics, fluorescence, cancer, tumours, drugs, nanomedicine, biomedical materials, dyes, toxicologyOther keywords: imaging agent, cancer tumours, cancer diagnosis, PEG‐citrate dendrimer‐G, FITC dye, cancer cells, FITC loading, vitro imaging, dendrimer‐FITC, CT imaging, targeting nature, promised dendrimer, fluorescent images, imaging ability, Iohexol/FITC