Current Physical Chemistry - Volume 5, Issue 3, 2015

Thin film La0.9Sr0.1Ga0.8Mg0.2O3-δ (LSGM) has been successfully fabricated as an electrolyte layer on an anode-supported substrate at 700°C with the pulsed laser deposition (PLD) technique. Sr2Fe1.5Mo0.5O6-δ (SFM) as both anode and cathode materials is discussed in this work. As the anode part, SFM is ball-milled with different weight ratios (10, 20, 30 wt %) of starch as pore former to achieve an anode layer with adequate porosity and good mechanical stability. Also, the sintering temperatures of the SFM anode layers (1150, 1200, 1250, 1350°C) are investigated to find an optimum porosity for catalytic reaction and thin film electrolyte deposition. Characterization of the microstructure morphology indicates that the proper anode composition is SFM with 10 wt % starch sintering at 1200°C. A 7 μm-thick LSGM electrolyte layer is dense and no cracks are found at the interface between anode and electrolyte. Pure SFM is painted onto the electrolyte and calcined at 1150°C as the cathode layer. The post-annealing process of the deposited LSGM film is also included in the cathode firing procedure. No reaction between SFM electrode and LSGM electrolyte occurs.

Background: Ancient bacterial enzymes have remarkable similarity with modern bacterial and mammalian enzymes. The AF2372 and MJ0109 gene products that cleave two sugars inositol-1-phosphate and fructose 1,6, bisphosphate are hyperthermophilic enzymes that are remarkably stable and easily purified. These ancient bacterial enzymes are highly homologous with human enzymes that cleave the same substrates. Methods: In this study inhibitors for E. coli Aspartate Transcarbamoylase (ATCase), a distant relative of the enzymes that cleave sugar phosphates, were synthesized and tested in the AF2372 and MJ0109 active sites in kinetic inhibitory assays. Structural comparisons and molecular docking were done with Human Inositol Monophosphatase (IMPase) and Fructose 1,6 bisphosphatase (FBPase) to predict possible conformations of the inhibitors in the phosphatase active sites. Results: The ATCase inhibitor Inh_3 (3,5-Bis(2-phosphonoacetamido)benzoic Acid) was most effective with AF2373 and MJ0109 gene products in the enzymatic inhibitory assay with a Ki of 0.0850 and 0.110 μM respectively. Docking studies produced binding constants with Inh_3 with human FBPase and FBPase within the low micromolar range. Conclusion: Taken together, enzymatic inhibitory assays, structural comparisons of the ancient bacteria and human species, and molecular docking of the putative inhibitors with Human IMPase and FBPase reveal that these ATCase inhibitory molecules may have relevance as potential inhibitors or lead compounds for these drug targets.

Structural characterization of powdered samples of β-chitin and chitosan is reported. β-chitin extracted from squid pens (Doryteuthis spp.) and chitosan produced by submitting beta-chitin to high intensity ultrasonication while suspended in 40% aqueous sodium hydroxide (NaOH). The samples were analyzed by field emission scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and nuclear magnetic resonance spectroscopy. Targeting a better understanding of the experimental data, the repeating units occurring predominantly in chitin (2-acetamido-2-deoxy-D-glycopiranose) and chitosan (2- amino-2-deoxy-D-glycopiranose) were adopted as model systems to study their physical and chemical properties by means of Kohn–Sham density functional theory and time-dependent density functional theory calculations using B3LYP hybrid XC functional with the 6-31+G(d, p) basis set. A fundamental understanding of the structure and electronic properties of chitin and chitosan at the atomic scale is required for the future development of new technologies based on these biopolymers.

SrSnO3@TiO2 and SrSnO3@ZrO2 core-shell nanoparticles were synthesized using the modified-Pechini method by impregnating the shell material on commercial materials (core) using a polymeric resin. The formation of SrSnO3 on TiO2 was confirmed by Xray diffraction and infrared spectroscopy, while superposition with ZrO peaks/bands occurred making this evaluation more difficult. Micrographs obtained using field emission scanning electron microscopy and transmission electron microscopy confirmed the dispersion of the perovskite phase on TiO2 and on ZrO2. The methodology applied in this study is promising in the synthesis of core@shell systems, using water as solvent and a low heat treatment temperature.

We present a review on fuel cells with emphasis on solid oxide fuel cells (SOFCs). We give an overview of proton exchange membrane, alkaline, phosphoric acid, molten carbonate and direct methanol fuels cells. For SOFCs we discuss electrolytes, anodes, cathodes, interconnects, fabricating processes, materials alternatives and industry. We also give an overview on thermodynamics, electrochemistry and kinetics of fuel cell reactions, mathematical models, fluid dynamics and simulation/computational methods in fuel cells (MM, HF, SE, HF, QM/MM, DFT, MC, MD, FF, Periodic, hybrid, coarse grain). Which are the best SOFCs electrolytes and how they work. We discuss breakthroughs, recent developments and the next generation fuel cells.

The neurogeneration observed in Alzheimer's disease (AD) is due to the formation of two abnormal structures in the brain of patients with this disease, i.e. neurofibrillary tangles and amyloid plaques. The amyloid plaques are formed by fragments of insoluble beta-amyloid peptides generated by cleaving the amyloid precursor protein (APP) by the beta-secretase enzyme (BACE 1). To date there are no marketed drugs that can stop or slow the progress of AD making it necessary for drug design research in this area, to be undertaken, BACE1 have presented as a major target for delaying the symptoms of AD, since it would prevent inhibition of the formation of insoluble fragments of beta-amyloid protein, and therefore the formation of amyloid plaques. The present study is aimed at screening millions of chemical compounds with pharmaceutical characteristics present in commercial databases, using virtual screening techniques to identify compounds that would inhibit BACE1. Two strategies have been proposed for this: (i) similarity virtual screening followed by docking and (ii) a pharmacophore approach followed by similarity virtual screening. After filtering the compounds, pharmacokinetic and toxicity properties were predicted. Finally two compounds one from each strategy was selected, which could eventually lead to in vitro studies of biological activity.

ZnO is a semiconductor material largely employed in the development of electronic and optical devices, as well as photocatalytic processes due to its single electronic property. Calculations based on DFT/B3LYP were performed to evaluate the electronic, optical and structural properties of S-doped ZnO material at 6.25 %. The theoretical results indicate the improvement of electronic and optical properties by decreasing the band-gap which caused by contribution of S atoms to Valence Band from energetic levels higher than O atoms. Such band-gap decrease allied to the direct conduction process expected to doped materials suggests the S-doped ZnO material as a viable alternative to application in the development of electro- optical devices to be applied in photocatalytic process. Structural results show that the doping process has low effect on lattice parameters of the ZnO material indicating that the compatibility between the doped ZnO material and the Si substrate is not changed.