An attrition game on a network ruled by Lanchester’s square law

We consider two-person zero-sum attrition games in which an attacker and a defender are in combat with each other on a network. The attacker marches from a starting node to a destination node, hoping that the initial members survive the march. The defender deploys his forces on arcs in order to intercept the attacker. If the attacker encounters the defender on an arc, the attacker incurs casualties according to Lanchester’s square law. We consider two models: a one-shot game in which the two players have no information about their opponents, and a two-stage game in which both players have some information about their opponents. For both games, the payoff is defined as the number of survivors for the attacker. The attacker’s strategy is to choose a path, and the defender’s is to deploy the defending forces on arcs. We propose a numerical algorithm, in which nonlinear programming is embedded, to derive the equilibrium of the game.     

Extraction of complexes of iron(III) and other metals with bis(2-ethylhexyl)phosphoric acid into molten biphenyl/naphthalene

The extraction behaviour of twelve metals as function of the concentration of nitric or hydrochloric acid is described; bis(2-ethylhexyl)phosphoric acid (BEHPA) and 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester are used as the extractants with 3:1 (w/w) biphenyl/ naphthalene (m.p. 52°C) as the molten solvent which is easily separated by cooling to room temperature. Scandium (III) and zirconium (IV) can be separated from uranium (VI), rare earth metals and some transition metals with BEHPA. The extraction behaviour of iron with both extractants is described in detail.     

Axial ligand substituted nonheme FeIV=O complexes: observation of near-UV LMCT bands and Fe=O Raman vibrations

Axial ligand substitution of a mononuclear nonheme oxoiron(IV) complex, [FeIV(O)(TMC)(NCCH3)]2+ (1) (TMC = 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane), leads to the formation of new FeIV=O species with relatively intense electronic absorption features in the near-UV region. The presence of these near-UV features allowed us to make the first observation of Fe=O vibrations of S = 1 mononuclear nonheme oxoiron(IV) complexes by resonance Raman spectroscopy. We have also demonstrated that the reactivity of nonheme oxoiron(IV) intermediates is markedly influenced by the axial ligands.     

Studies aimed at the total synthesis of azadirachtin. A modeled connection of C-8 and C-14 in azadirachtin

[reaction: see text] Studies on the connection between the right and left segments of azadirachtin are described. The Ireland-Claisen rearrangement of Li-enolate of the modeled ester with dichlorodimethylsilane in toluene afforded the desired limonoid framework stereoselectively in good yield.     

Resonance raman investigation of the specific sensing mechanism of a target molecule by gas sensory proteins

Specific sensing of gas molecules such as CO, NO, and O2 is a unique function of gas sensory hemoproteins, while hemoproteins carry out a wide variety of functions such as oxygen storage/transport, electron transfer, and catalysis as enzymes. It is important in gas sensory proteins that the heme domain not only recognizes its target molecule but also discriminates against other gases having similar molecular structures. Coordination of a target molecule to the heme is assumed to alter the protein conformation in the vicinity of heme, and the conformation change is propagated to the effector domain where substrate turnover, DNA binding, or interaction with a signal transduction protein is performed differently than the binding of other gases. To understand the appearance of such a specificity, we focus our attention on the ligand-protein interactions in the distal side of heme. In practice, the metal-ligand vibrations as well as internal modes of ligand and heme are measured with resonance Raman spectroscopy for wild-type and some mutant proteins with full-length or limited sensory regions. On the basis of such observations together with the knowledge currently available, we discuss the mechanism of specific sensing of a diatomic molecule in gas sensory proteins.     

Seed polymerization of tetraethyl ortho-silicate in the presence of rod-like colloidal particles of anionic palygorskite and cationic β-FeO(OH)

Kinetic analyses were made of the seed polymerization of tetraethyl ortho-silicate (TEOS) in the presence of rod-like colloidal particles of palygorskite and cationic -FeO(OH) by turbidity and dynamic light-scattering measurements. Transmission electron microscopic measurements supported the formation of core-shell particles. The seed polymerization of TEOS took place exclusively on the surfaces of palygorskite. The main cause of the observation is due to the fact that the main component of palygorskite is SiO₂ and the affinity between palygorskite and TEOS is high, though the electrostatic repulsion between them is not favorable for shell formation. The shell formation of silica on a -FeO(OH) particle also proceeded. The electrostatic attraction forces between the anionic polar TEOS monomers and cationic -FeO(OH) particles played an important role in shell formation. These results are consistent with a polymerization mechanism consisting of the formation of small preliminary particles followed by their coalescence on the surfaces of the seeds to give the final large particles coated with silica layers.     

An accurate quantitative analysis of polymorphs based on artificial neural networks

Measurement precision based on homogeneous and accurate standard samples has been reported to result in significant improvement in the sensitivity and accuracy of the quantitative analysis of polymorphic mixtures. The purpose of this study was to further improve the accuracy of the quantitation based on data processing by artificial neural networks (ANNs), using such high quality standard samples. Homogeneous powder mixtures of - and γ-forms of indomethacin (IMC) at various ratios (0–50% -form content) were subjected to X-ray powder diffractometry. The two diffraction peaks selected as the best combination in multiple linear regression (MLR) were used in the ANN with an extended Kalman filter as a training algorithm. The results obtained by ANN had better predictive accuracy at lower contents (0–5%) compared to those of MLR. ANNs for the diffraction data based on high quality standard samples provide an extremely precise and accurate quantification for polymorphic mixtures.     

Use of vitamin B2 for fluorescence detection of thymidine-related single-nucleotide polymorphisms

In combination with abasic site (AP site)-containing DNAs, potential use of a biotic fluorescence compound, Vitamin B₂ (riboflavin), is demonstrated for the fluorescence detection of the thymine (T)-related single-nucleotide polymorphisms. Our method is based on construction of the AP site in DNA duplexes, which allows small ligands to bind to target nucleotides accompanied by fluorescence signaling: an AP site-containing probe DNA is hybridized with a target DNA so as to place the AP site toward a target nucleobase, by which hydrophobic microenvironments are provided for ligands to recognize target nucleotides through stacking and hydrogen-bonding interactions. In 10 mM sodium cacodylate buffer solutions (pH 7.0) containing 100 mM NaCl and 1.0 mM EDTA, Vitamin B₂ is found to selectively bind to T (K₁₁ = 1.8 × 10⁶ M⁻¹ at 5 °C) over other nucleobases, and this is accompanied by significant quenching of its fluorescence. While the sensing functions depend on the flanking sequences to the AP site, Vitamin B₂ is applicable to the detection of T/C (cytosine), T/G (guanine) and T/A (adenine) mutation sequences of the CYP2A6 gene, where the flanking nucleobases are guanines in both positions (-GXG-, X = AP site).     

Synthesis of optically active conjugated polymers containing platinum in the main chain: Control of the higher‐order structures by substituents and solvents

The Sonogashira–Hagihara coupling polymerization of d ‐hydroxyphenylglycine‐derived diiodo monomers 1–4 and platinum‐containing diethynyl monomer 5 gave the corresponding polymers [poly( 1–5 )–( 2–5 )] with number‐average molecular weights of 19,000–25,000 quantitatively. The polymers were soluble in CHCl₃, CH₂Cl₂, THF, and DMF. CD and UV–vis spectroscopic analysis revealed that amide‐substituted polymers [poly( 1–5 ) and poly( 2–5 )] formed chiral higher‐order structures in solution, while ester‐substituted polymers [poly( 3–5 ) and poly( 4–5 )] did not. Poly( 1–5 ) formed one‐handed helices in THF/toluene mixtures, while it formed chiral aggregates in THF/MeOH mixtures. Poly( 1–5 ) emitted fluorescence with quantum yields ranging from 0.8 to 1.3%. The polymers usually aggregated in the solid state. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 2452–2461