Comparative study of dielectric,mechanical, and nuclear magnetic relaxations in linear polyethylene. II. Relaxation spectroscopy of the α, β, and γ loss bands with special emphasis on fine structure

Dielectric, mechanical, and NMR retardation (correlation) spectra for relaxations in linear polyethylene were calculated in normalized form and intercompared. For each of the two local-mode relaxations in the γ region, called γ₁ and γ₂, these spectra are found to be in excellent agreement. For the α region, the spectra for two mechanical processes, called α₁ and α₂, two NMR processes, called α′ and α, and one dielectric process α were calculated. Excellent agreement is found between the spectra for the dielectric α and NMR α′ processes and also spectra for the mechanical α₂ and NMR α processes, due to molecular motion in the interior of crystals. However, the spectrum for the mechanical α₁ process is different from that for the dielectric α and NMR α′ processes, though the activation energy for the first process is almost the same as for the other two. This behavior is interpreted on the assumption that the dielectric α and NMR α′ processes are caused by molecular motion in lamellar surface layers while the mechanical α₁ process is due to grain-boundary slip with viscous resistance of the surface layers in the boundaries. The shapes of the spectra, including the spectrum for the β process, are not affected by diluent.     

Anomalous binding profile of phenylboronic acid with N-acetylneuraminic acid (Neu5Ac) in aqueous solution with varying pH

Borates are known to interact with carbohydrate moieties expressed on the surface of biological membranes of a variety of cells, viruses, bacteria, and fungi. This study revealed the anomalous binding profile of borate in aqueous solution with N-acetylneuraminic acid (Neu5Ac, sialic acid) as a potential receptor site on the surfaces of biological membranes using (11)B, (1)H, (13)C, and (15)N nuclear magnetic resonance spectroscopies. 3-(Propionamido)phenylboronic acid (PAPBA) was chosen as the model borate compound. The equilibrium constant (K) for Neu5Ac binding to PAPBA was compared with those for glucose, mannose, and galactose, which are the major carbohydrate constituents of glycoproteins and glycolipids expressed on biological membranes. In the Neu5Ac/PAPBA system, the unusual pH dependency of the K values, a decrease in K with increasing pH, was observed, suggesting the formation of a trigonal-formed complex stabilized by the coordination of an amide group of Neu5Ac at the C-5 position to the boron atom, forming intramolecular B-N or B-O bonding. Furthermore, the anomalously high complexing ability at physiological pH 7.4 was confirmed for this system, with the K value 37.6 which is approximately 7 times higher than that for glucose. This exceptionally high value of K at physiological pH, compared to those of other sugars, strongly suggests that the boronic acid selectively recognizes the Neu5Ac residues of the glycosylated components including glycoproteins and gangliosides existing on the surface of the biological membranes.     

Chelate resin-iron(II) complex: Adsorption and desorption of nitrogen monoxide at the dry state

A chelate resin-immobilized iron(II) complex was prepared from iron(II) and poly(styrenecodivinylbenzene) which is functionalized by iminodiacetic acid group. It is activated by drying after having been washed with methanol. The resin complex can rapidly adsorb nitrogen monoxide, and the nitrogen monoxide adsorbed on the complex can be released by the treatment with heat. The adsorption of nitrogen monoxide proceeds through the 1:1 complex formation of the NO molecule with the iron(II) atom, and its complex formation constant was calculated as 8330 atm^?1 at room temperature from Langmuir plots. This value does not depend on the solvents used for washing. The activation of the resin complex by the treatment of washing with methanol is derived by increasing the amount of effective iron(II) ions due to the increase in the surface area. Moreover, this resin complex was revealed to have high complex formation constant with NO and high durability to dioxygen compared with an aqueous solution of ethylenediaminetetraacetato–iron(II) complex, which is the corresponding monomeric absorbent commonly used for nitrogen monoxide.     

Synthesis and evaluation of novel 2-oxo-1,2-dihydro-3-quinolinecarboxamide derivatives as potent and selective serotonin 5-HT4 receptor agonists

A series of 8'-substituted N-(endo-8-azabicyclo[3.2.1]oct-3-yl)-1-isopropyl-2-oxo-1,2-dihydro-3-quinolinecarboxamides were synthesized. The 5-HT4 receptor agonistic activity was evaluated using the isolated guinea pig ileum preparation. Of the compounds synthesized, N-(endo-8-(3-hydroxypropyl)-8-azabicyclo[3.2.1]oct-3-yl)-1-isopropyl-2-oxo-1,2-dihydro-3-quinolinecarboxamide (15a, TS-951) exhibited the most potent serotonin 5-HT4 receptor agonistic activity. This compound had a high affinity for the serotonin 5-HT4 receptor although it had no affinities for other broad spectrum receptors. Furthermore, it remarkably enhanced gastrointestinal motility in conscious fed dogs without unfavorable effects that non-selective serotonin 5-HT4 receptor agonist has. TS-951 may be useful in improving gastrointestinal dysfunction.     

Spectral representation for Schrödinger operators with long-range potentials

A spectral representation for the self-adjoint Schrödinger operator H = ?Δ + V(x), x? R³, is obtained, where V(x) is a long-range potential: $\text{V(x) = O(¦ x ¦}{}^{\mathrm{<mtext>?</mtext><mtext>(1</mtext><mtext>2)</mtext><mtext>?\delta </mtext>}}\text{)}$, grad $\text{V(x) = O(¦ x ¦}{}^{\mathrm{<mtext>?</mtext><mtext>(3</mtext><mtext>2)</mtext><mtext>?\delta </mtext>}}\text{)}$, $\text{ΛV(x) = O(¦ x}\text{s}\text{?}{}^{\mathrm{?\delta }}\text{) (δ > 0), Λ}$ being the Laplace-Beltrami operator on the unit sphere Ω. Namely, we shall construct a unitary operator $\text{F}$ from PL₂(R³) onto $\text{L}{}_2\text{((0, ∞); L}{}_2\text{(Ω)), P}$ being the orthogonal projection onto the absolutely continuous subspace for H, such that for any Borel function α(λ),

$\text{(α(H)(Pf,g)=}\text{∫}\text{0}\text{∞}\text{(α(λ)(Ff)(λ),(Fg)(λ))L}{}_2\text{(ω) dλ}$

.     

ACTION SPECTRA FOR BIOSYNTHESIS OF CHLOROPHYLLS a AND b AND β-CAROTENE

Abstract— Action spectra for the formation of chlorophyll b and β-carotene were determined with etiolated wheat leaves and compared with the action spectrum for the formation of chlorophyll a determined for the same samples. The action spectra were measured with etiolated leaves which had been pre-illuminated for 10 min and incubated in the dark for 4 h to eliminate induction of pigments. The action spectra for chlorophyll b and for β-carotene accorded with the action spectrum for chlorophyll a and with the absorption spectrum of protochlorophyllide in intact etiolated leaves. It is postulated from this result with chlorophyll b that this pigment is formed from protochlorophyllide through chlorophyll a or some intermediates to chlorophyll a. Complexing between chlorophylls and β-carotene and proteins is postulated to interpret the action spectrum for β-carotene. It is assumed that the low concentration of chlorophylls formed photochemically limits the rate of complexing, and that consumption of β-carotene for the complexing induces formation of new β-carotene.     

Syntheses of (1,1-dihydroperfluoroalkyl)aryliodonium triflates and their analogues

(1,l-Dihydroperfluoroalkyl)phenyl- and -$\text{p}$-fluorophenyliodonium triflates $\text{2}$ and $\text{3}$ were synthesized by the reaction of l-bis(trifluoroacetoxy)iodo-1,l-dihydroperfluoroalkanes $\text{1}$ with triflic acid and benzene or fluorobenzene in 1,1,2-trichlorotrifluoroethane. The use of fluorosulfonic acid and sulfuric acid instead of triflic acid afforded (1,l-dihydroperfluoroalkyl) phenyliodonium fluorosulfonate $\text{4}$ and sulfate $\text{5}$, respectively. Similarly, (1,1,ω-trihydroperfluoroalkyl)phenyliodonium triflate $\text{7}$ and 1,1,5,5-tetrahydroperfluoropentane-l,5-bisphenyliodonium triflate $\text{9}$ were synthesized.     

Determination of thallium in soils by flame atomic absorption spectrometry

A method is described for the determination of Tl in soils by FAAS, involving extraction of Tl from 5 g of soil by digestion with HClO₄/HNO₃ followed by separation of the extracted Tl into 5 mL of diisopropylether from HBr solution, including Ce(SO₄)₂. Tl in the organic phase is determined by direct aspiration into the spectrophotometer. The percentage relative standard deviation (% RSD) for 5 replicate samples is about 1%. The detection limits (S/N = 3) of this method are 0.001 mg/L for aqueous solution and 0.02 mg/kg DW for soil, when 50 mL of soil solution corresponding to 2.5 g soil are used. The Tl concentration even of unpolluted soils can be determined. The method was shown to be unaffected by the presence of various ions in soil and was able to recover nearly 100% Tl added to soils. The arithmetic mean (range) of 18 Japanese unpolluted surface soils was 0.33 (0.10–0.56)mgTl/kg DW.