Preparation and formation mechanism of three-dimensionally ordered macroporous (3DOM) MgO, MgSO4, CaCO3, and SrCO3, and photonic stop band properties of 3DOM CaCO3

Three-dimensionally ordered macroporous (3DOM) magnesium (Mg) oxide (MgO), MgSO₄, calcium (Ca) carbonate (CaCO₃), and strontium (Sr) carbonate (SrCO₃) were prepared using a colloidal crystal of polymer spheres as a template. Ethanol or ethanol-water solution of metal salts (acetate or nitrate) and citric acid was infiltrated into the void of the colloidal crystal template of a monodispersed poly(methyl methacrylate) (PMMA) sphere. Heating of this PMMA-metal salt-citric acid composite produced the desired well-ordered 3DOM materials with a high pore fraction, which was confirmed by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and ultraviolet-visible (UV-vis) diffuse reflectance spectra. The presence of citric acid is crucial for production of the 3DOM structures. Reaction of citric acid with metal salt produces metal citrate solid in the void of PMMA spheres, which is necessary to maintain the 3DOM structure during the calcination process. 3DOM CaCO₃ shows opalescent colors because of it's photonic stop band properties.     

Sodium Ion Batteries using Ionic Liquids as Electrolytes

Sodium ion batteries have been developed using ionic liquids as electrolytes. Sodium is superior to lithium as a raw material for mass production of large‐scale batteries for energy storage due to its abundance and even distribution across the earth. Ionic liquids are non‐volatile and non‐flammable, which improved the safety of the batteries remarkably. In addition, operation temperatures were extended to higher values, improving the performance of the batteries by facilitating the reaction at the electrode and mass transfer. Binary systems of sodium and quaternary ammonium salts, such as 1‐ethyl‐3‐methylimidazolium and N‐methyl‐N‐propylpyrrolidinium bis(fluorosulfonyl)amide, were employed as electrolytes for sodium ion batteries. A series of positive and negative electrode materials were examined to be combined with these ionic liquid electrolytes. A 27 Ah full cell was fabricated employing sodium chromite (NaCrO₂) and hard carbon as positive and negative electrode materials, respectively. The gravimetric energy density obtained for the battery was 75 Wh kg^?1 and its volumetric energy density was 125 Wh L^?1. The capacity retention after 500 cycles was 87 %. Further improvement of the cell performance and energy density is expected on development of suitable electrode materials and optimization of the cell design.     

Syntheses and Properties of (Nitronyl nitroxide)-substituted Tri-phenylamine ortho-Bridged by Two Oxygen and Sulfur Atoms

A nitronyl nitroxide unit ( NN ) was linked with a triphenylamine-based condensed polycyclic skeleton DOTT to form a radical substituted donor NN - DOTT . X-ray crystal structure analysis demonstrated a flat bowl shape of the DOTT unit. EPR spectra showed the localization of electron spin on the NN unit. Chemical oxidation of the DOTT unit produced radical-substituted radical cation salts NN - DOTT ⁺ ⋅ SbF₆⁻ and NN - DOTT ⁺ ⋅ FeBr₄⁻ that are stable under ambient conditions. The magnetic behavior of NN - DOTT ⁺ ⋅ SbF₆⁻ is characterized by the strong intramolecular ferromagnetic interaction between NN and DOTT ⁺. The X-ray structural analysis of NN - DOTT ⁺ ⋅ FeBr₄⁻ shows planar structure of DOTT and 1D mixed-stack column of NN-DOTT ⁺ and FeBr₄⁻. Magnetic measurements established that NN - DOTT ⁺ ⋅ FeBr₄⁻ undergoes magnetic phase transition into a weak ferromagnet at 7 K.     

Active space and basis set effects in CASPT2 models of the 1,3‐butadiene‐ethene cycloaddition and the 1,3‐butadiene dimerization

The first step of the asynchronous biradical, stepwise biradical, and concerted mechanisms of the 1,3‐butadiene Diels–Alder reactions with both ethene and itself was studied using CASPT2 to determine the influence of basis set and active space on reaction barriers. CASPT2(6,6) with the cc‐pVDZ, 6‐311+G(3df,2p) and cc‐pVTZ basis sets provided the best results with average errors below 3.1 kJ mol^?1 with respect to the experimental result. Increasing the active space size also had little effect on the calculated reaction barriers. With respect to experimental results, uncontracted multireference averaged quadratic coupled cluster (MRAQCC) produced superior barriers than internally contracted MRAQCC by 16.1–39.3 kJ mol^?1. The inability of CASSCF to locate transition states for some of the cycloadditions across the butadiene‐ethene and butadiene dimerization reactions is also rationalized. CASPT2 suggests a preference for the concerted mechanism of the butadiene‐ethene reaction, however, no basis set yielded a preference for any of the butadiene dimerization pathways. © 2015 Wiley Periodicals, Inc.     

Capturing student mathematical engagement through differently enacted classroom practices: applying a modification of Watson's analytical tool

This study examined student mathematical engagement through the intended and enacted lessons taught by two teachers in two different middle schools in Indonesia. The intended lesson was developed using the ELPSA learning design to promote mathematical engagement. Based on the premise that students will react to the mathematical tasks in the forms of words and actions, the analysis focused on identifying the types of mathematical engagement promoted through the intended lesson and performed by students during the lesson. Using modified Watson's analytical tool (2007), students’ engagement was captured from what the participants’ did or said mathematically. We found that teachers’ enacted practices had an influence on student mathematical engagement. The teacher who demonstrated content in explicit ways tended to limit the richness of the engagement; whereas the teacher who presented activities in an open-ended manner fostered engagement.     

Correlated ab initio quantum chemical study of the interaction of the Na+, Mg2+, Ca2+, and Zn2+ ions with the tautomers of cytosine

The interaction of the metal ions Na(+), Mg(2+), Ca(2+), and Zn(2+) with cytosine have been reinvestigated at the density functional, M?ller-Plesset, and coupled cluster levels of theory, including hitherto unstudied tautomeric forms. It has been found that the interaction of the metal ion has a varying and often significant effect on the stabilities of the various tautomers, in some cases making most stable rare tautomeric forms. The results have been analyzed with respect to method and role of ion in binding, and confirm that, as has been found for the base cytosine tautomers, B3LYP does not give energetics consistent with highly accurate post-SCF methods for their interaction with these metal ions.     

Thermodynamics of the O2/O2− redox couple in molten (LiCl + KCl + Li2O) systems

Activity coefficients of oxide ion were determined by the measurements of the standard formal potential of O₂/O^2? with a boron-doped diamond (BDD) electrode in molten (LiCl + KCl): LiCl:KCl = {58.5:41.5 (eutectic), 65:35, 70:30, 75:25} mol% at T = (673 to 803) K. The activity coefficient decreases with the increase of the LiCl content in the melt: (18.7 ± 1.5, 7.7 ± 1.0, 4.1 ± 0.4, and 1.6 ± 0.1), respectively, at T = 773 K in each melt. The result is explained by the attractive force between Li⁺ and O^2? which is stronger than that between K⁺ and O^2?.     

Analysis of glycoprotein-derived oligosaccharides in glycoproteins detected on two-dimensional gel by capillary electrophoresis using on-line concentration method

Capillary electrophoresis (CE) is an effective tool to analyze carbohydrate mixture derived from glycoproteins with high resolution. However, CE has a disadvantage that a few nanoliters of a sample solution are injected to a narrow capillary. Therefore, we have to prepare a sample solution of high concentration for CE analysis. In the present study, we applied head column field-amplified sample stacking method to the analysis of N-linked oligosaccharides derived from glycoprotein separated by two-dimensional gel electrophoresis. Model studies demonstrated that we achieved 60-360 times concentration effect on the analysis of carbohydrate chains labeled with 3-aminobenzoic acid (3-AA). The method was applied to the analysis of N-linked oligosaccharides from glycoproteins separated and detected on PAGE gel. Heterogeneity of alpha1-acid glycoprotein (AGP), i.e. glycoforms, was examined by 2D-PAGE and N-linked oligosaccharides were released by in-gel digestion with PNGase F. The released oligosaccharides were derivatized with 3-AA and analyzed by CE. The results showed that glycoforms having lower pI values contained a larger amount of tetra- and tri-antennary oligosaccharides. In contrast, glycoforms having higher pI values contained bi-antennary oligosaccharides abundantly. The result clearly indicated that the spot of a glycoprotein glycoform detected by Coomassie brilliant blue staining on 2D-PAGE gel is sufficient for quantitative profiling of oligosaccharides.