Molecular orientation and mechanical anisotropy of polypropylene sheet containing N,N′‐dicyclohexyl‐2,6‐naphthalenedicarboxamide

Effect of mixing and processing conditions at T‐die extrusion on the structure and mechanical properties is studied for isotactic polypropylene (PP) containing a small amount of β‐form nucleating agent, N,N′‐dicyclohexyl‐2,6‐naphthalenedicarboxamide. It is found that trigonal β crystals are predominantly formed in the extruded samples containing the nucleating agent irrespective of the mixing and processing conditions, leading to the marked mechanical toughness. On the contrary, the molecular orientation is significantly affected by the mixing and processing conditions. In particular, it should be noted that PP molecules in the extruded sheet which was mixed at high temperature (260 °C) and extruded at low temperature (200 °C) orient perpendicular to the applied flow direction. As a result, the sheet shows anomalous mechanical anisotropy. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 424–433, 2009     

Role of Arg123 in Light‐driven Anion Pump Mechanisms of pharaonis Halorhodopsin†

Halorhodopsin (HR) acts as a light‐driven chloride pump which transports a chloride ion from the extracellular (EC) to the cytoplasmic space during a photocycle reaction that includes some photointermediates initiated by illumination. To understand the chloride uptake mechanisms, we focused on a basic residue Arg123 of HR from Natronomonas pharaonis (NpHR), which is the only basic residue located in the EC half ion channel. By the measurements of the visible absorption spectra in the dark and the light‐induced inward current through the membrane, it was shown that the chloride binding and transport ability of NpHR completely disappeared by the change of arginine to glutamine. From flashphotolysis analysis, the photocycle of R123Q differed from that of wildtype NpHR completely. The response of the R123H mutant depended on pH. These facts imply that the positive charge at position 123 is essential for chloride binding in the ground state and for the chloride uptake under illumination. On the basis of the molecular structures of HR and the anion‐transportable mutants of bacteriorhodopsin, the effects of the positive charge and the conformational change of the Arg123 side chain as well as the chloride‐pumping mechanism are discussed.     

Highly efficient substitution of allylic picolinates with copper reagents derived from aryl-, alkenyl-, furyl-, and thienyl-lithiums

Substitution of optically active allylic picolinate, cis R¹-CH(OC(O)(2-Py))CHCHR² (R¹=(CH₂)₂Ph, R²=CH₂OTBS), with phenylcopper reagents derived from salt free PhLi (2 equiv) and CuBr·Me₂S (2 and 1 equiv, respectively) was highly promoted by MgBr₂ (3 equiv), producing anti S_N2′ product regio- and stereoselectively. This reagent system was proven to be general with several picolinates (R¹, R²: Ph(CH₂)₂, PMBO(CH₂)₃, Me, TBSOCH₂, PMBOCH₂, c-Hex). Furthermore, aryl copper reagents prepared from ArLi, which was in turn prepared by Li-halogen exchange, was proven to be compatible with the substitution in the presence of larger quantity of MgBr₂ than that of LiX coproduced by the exchange. Substitution was not interfered with the steric hindrance on aryl coppers (Ar: 2-MeOC₆H₄, 2,6-(MOMO)₂-4-MeC₆H₂, 2,6-Me₂C₆H₃, etc.). Similarly, stereodefined cis and trans alkenyl, furyl, and thienyl reagents gave the corresponding anti S_N2′ products efficiently.     

Immunoassay based on a polyclonal antibody for sex steroid hormones produced by a heterogeneous hapten-conjugated immunogen: Estimation of its potentiality and antibody characteristics

A method in which antibodies are produced by using an immunogen heterogeneously conjugated with two or more kinds of haptens having unlike chemical structures against a same carrier protein was offered as an efficient approach for development of antibody to low molecular compounds. To appreciate the potentiality of the approach, 17β-estradiol (E2) and testosterone were selected as model compounds. The I₅₀ values of antiserum developed were 6 and 8 μg L⁻¹ with the detection limits of 0.02 and 0.15 μg L⁻¹ for E2 and testosterone, respectively. Antiserum owned an interesting characteristic that it was possible to independently analyze E2 and testosterone without mutual interference by making proper use of coating antigens. When using β-estradiol 17-hemisuccuinate (EH) conjugated with bovine serum albumin (BSA) as a coating antigen, the enzyme-linked immunosorbent assay (ELISA) was very selective to E2 and some estrogen analogues. Therefore, if testosterone coexisted in the ELISA for E2 detection, it showed no interference with it. From these findings, it was suggested that the verified method was an efficient and rational approach in development of polyclonal antibody to low molecular compounds.     

Determination of Ubiquinone in Blood by High-Performance Liquid Chromatography with Post-Column Fluorescence Derivatization Using 2-Cyanoacetamide

It was shown that ubiquinone (CoQ₁₀) and ubiquinol (CoQ₁₀H₂) produce fluorescence products under alkaline conditions when reacted with 2-cyanoacetamide. The reaction mixture from CoQ₁₀ gave fluorescence with excitation and emission maximum wavelengths at 442 nm and 549 nm, respectively. This reaction was considered to proceed via Craven’s reaction. Moreover, 2-cyanoacetamide was shown to be a useful reagent for high-performance liquid chromatography (HPLC) with post-column fluorescence derivatization of CoQ₁₀ and CoQ₁₀H₂ in blood. CoQ₁₀ showed a linear response in the range of 0.32–1276 ng, and the detection limit (S/N = 3) was 0.16 ng. Moreover, the sample pretreatment by deproteinization and extraction of CoQ₁₀ and CoQ₁₀H₂ from plasma using 1-propanol with potassium formate was effective for excellent separation of CoQ₁₀ and CoQ₁₀H₂ from other fluorescent substances in the blood. This simple and rapid pretreatment was considered to minimize the oxidation of CoQ₁₀H₂. On the other hand, CoQ₁₀ and CoQ₁₀H₂ in plasma samples obtained by finger prick were detected, as in venous blood obtained by venipuncture. Our method involving the simple and rapid collection of plasma by finger prick and sample pretreatment is thought to be applicable for the determination of CoQ₁₀H₂/total CoQ₁₀ ratio as a biomarker of oxidative stress.     

Efficient decoherence-free entanglement distribution over lossy quantum channels

We propose and demonstrate a scheme for boosting the efficiency of entanglement distribution based on a decoherence-free subspace over lossy quantum channels. By using backward propagation of a coherent light, our scheme achieves an entanglement-sharing rate that is proportional to the transmittance T of the quantum channel in spite of encoding qubits in multipartite systems for the decoherence-free subspace. We experimentally show that highly entangled states, which can violate the Clauser-Horne-Shimony-Holt inequality, are distributed at a rate proportional to T.     

Design of laser interferometric system for measurement of gear tooth flank

A laser interferometric system (LIS) based on oblique incidence and phase shifting technique has been designed for the measurement of gear tooth flank. For a spur involute gear with a module of 2.0, 60 teeth, and a 20-mm facewidth, some critical parameters of the LIS are calculated, the oblique incidence angle is 84.5°, the beam diameter is 20 mm, and the focal length of imaging lens is 100 mm, and the resolution of CCD camera is 1360 × 1024 pixels. To test the capability of the designed LIS, the numerical simulation is done for the LIS. The actual LIS is built on an optical platform and the experiment is carried out. Both interference fringe patterns from the numerical simulation and the actual experiment are good and coincident with each other, which show the designed LIS is feasible.