Reaction of 6-chloro-2-[1-methyl-2-(N-methylthiocarbamoyl)]-hydrazinoquinoxaline 4-oxide with dimethyl acetylenedicarboxylate

The reaction of 6-chloro-2-(1-methylhydrazino)quinoxaline 4-oxide 4a with methyl or phenyl isothiocyanate gave 6-chloro-2-[1-methyl-2-(N-methylthiocarbamoyl)hydrazino]quinoxaline 4-oxide 7a or 6-chloro-2-[1-methyl-2-(N-phenylthiocarbamoyl)hydrazino]quinoxaline 4-oxide 7b , respectively, whose reaction with dimethyl acetylenedicarboxylate afforded 6-chloro-2-[N-methyl-N-(5-methoxycarbonylmethylene-3-methyl-4-oxo-2-thioxoimidazolidin-1-yl)]aminoquinoxaline 4-oxide 8a or 6-chloro-2-[N-methyl-N-(5-methoxycarbonylmethylene-4-oxo-3-phenyl-2-thioxoimidazolidin-1-yl)]aminoquinoxaline 4-oxide 8b , respectively.     

Inorganic chemical approaches to pharmacognosy. VII. X-ray fluorescence spectrometric studies on the inorganic constituents of crude drugs. (5). The relationship between inorganic constituents of plants and the soils on which they are grown

Inorganic constituents of the leaves of several kinds of plants growing on different soil types were investigated using energy-dispersive X-ray fluorescence spectrometry. The results can be summarized as follows: (1) Each plant exhibited a characteristic metals profile, even if they were grown on similar soil types. (2) As we would expect, the metals profile of the plant leaves depends on the inorganic constitution of the soil on which it is grown. However, the degree of the influence of the soil types on the metals profile of the plant differs according to the kind of inorganic element: Ca and Cu are almost independent of the soil types, but the Ti and Fe content is dependent upon the soil types. (3) Sr content of plant leaves is closely related to the ratio of Sr to Ca of the soil on which the plants are grown. (4) This information should be helpful in identifying the producing district or original plant of a crude drug by its metals profile.     

The thermal expansion of cellulose II and IIIII crystals

Highly crystalline samples of cellulose II and III_II have been prepared from repeated mercerization of ramie fibers and supercritical ammonia treatment of the mercerized ramie fibers, respectively. The thermal expansion behavior of cellulose II and III_II was investigated using X-ray diffraction at temperatures ranging from room temperature to 250 °C. With increasing temperature, the unit cell of cellulose II expanded in the lateral directions and contracted in the longitudinal direction, with the a and b axes increasing by 0.54 and 3.4%, respectively, and the c axis decreasing by 0.09%. The anisotropic thermal expansion in these three directions was closely related to the crystal structure and the hydrogen bonding in cellulose II. A similar anisotropic thermal expansion was also observed in cellulose III_II. Cellulose III_II expanded in the lateral direction but contracted in the longitudinal direction.     

Composition dependence of ordered structures in mixed micellar aqueous solutions of hydrophobically modified poly(ethylene glycol)s

Ordered structures of micellar aqueous solutions of poly(ethylene glycol) (PEG) monododecylether mixtures [octaethylene glycol monododecylether (C12E8) and poly(ethylene glycol) monododecylether (C12E25)] have been investigated as a function of the C12E8/C12E25 composition by means of X‐ray scattering. C12E8 and C12E25 have different chain lengths of corona PEG, that is, 8 and 25 repeating units, respectively. The following results have been obtained. First, in the C12E8‐rich and C12E25‐rich regions, the mixtures take hexagonal and cubic phases, respectively. The hexagonal phase remains over a wider range of compositions and is more stable for the mixing of the other component than the cubic phase. Second, in the C12E8‐rich region of the cylindrical hexagonal packing, the nearest‐neighbor micellar distance increases, whereas the association number density remains constant, with an increasing amount of mixed C12E25 possessing longer corona chains. Third, in contrast to this, the nearest‐neighbor micellar distance of the body‐centered cubic packing exhibits almost no change, whereas the association number increases as C12E8 of shorter corona chains is increasingly incorporated. Fourth, self‐consistent field calculations reasonably reproduce the experimental findings of the second and third observations. We discuss the phase stability and the structural changes with the composition in terms of differences in the PEG corona‐chain length. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2474–2483, 2005     

X‐ray diffraction study of the thermal expansion behavior of cellulose triacetate I

Highly crystalline samples of cellulose triacetate I (CTA I) were prepared from highly crystalline algal cellulose by heterogeneous acetylation. X‐ray diffraction of the prepared samples was carried out in a helium atmosphere at temperatures ranging from 20 to 250 °C. Changes in seven d‐spacings were observed with increasing temperature due to thermal expansion of the CTA I crystals. Unit cell parameters at specific temperatures were determined from these d‐spacings by the least squares method, and then thermal expansion coefficients (TECs) were calculated. The linear TECs of the a, b, and c axes were α_a = 19.3 × 10^?5 °C^?1, α_b = 0.3 × 10^?5 °C^?1 (T < 130 °C), α_b = ?2.5 × 10^?5 °C^?1 (T > 130 °C), and α_c = ?1.9 × 10^?5 °C^?1, respectively. The volume TEC was β = 15.6 × 10^?5 °C^?1, which is about 1.4 and 2.2 times greater than that of cellulose I_β and cellulose III_I, respectively. This large thermal expansion could occur because no hydrogen bonding exists in CTA I. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 517–523, 2009     

Highly sensitive chemiluminescence flow-injection detection of the red tide phytoplankton Heterosigma carterae

Two chemiluminescent flow-injection analysis systems for the detection of the red tide Phytoplankton Heterosigma carterae (formerly known as Heterosigma akashiwo) have been developed. In one system, the superoxide (O⁻₂) released by H. carterae reacts with 2-methyl-6-(p-methoxyphenyl)-3,7-dihydroimidazo[1,2-a]-pyrazin-3-one (MCLA), a superoxide specific probe. In the other system, the hydrogen peroxide released by H. carterae reacts with luminol catalyzed by Arthromyces ramosus peroxidase (ARP). The chemiluminescence is detected by a photomultiplier tube. This system is capable of the rapid determination of H. carterae; the time required for one measurement cycle is ca. 2 min using MCLA-dependant luminescence or 1 min in luminol/ARP luminescence. A linear response was observed from 10² to 10⁵ cells ml⁻¹ H. carterae. Several other species of phytoplankton gave no response using this system. The detection limit of this method is suitable for detecting H. carterae in the early stage of red tide formation.     

Assessment of T1 time course changes and tissue-blood ratios after Gd-DTPA administration in brain tumors

Sequential T1 changes in brain tumor tissue after Gd-DTPA administration were investigated in 10 patients, including 4 meningiomas, 2 gliomas, 3 metastatic cerebral tumors and 1 brain abscess. T1 values were measured serially for 60 minutes following Gd-DTPA injection using a magnetic focusing technique. In vitro T1 of the whole blood samples was also comparatively examined. Time processes in the tissue-blood ratio (TBR) were calculated from two-point relaxation rates at 5 and 30 minutes. The obtained ratios of TBR were ranged from 1.0 to 3.0, probably depending on histological types of brain tumor (the value of 1.0 to 1.5 for meningioma and 1.5 to 3.0 for glioma and metastatic tumor). No significant changes in the T1 value were observed in the examined normal tissue and peritumoral edema. These results indicate that Gd-DTPA plays an important role not only as an image enhancer for tumor tissue but also as an indicator for estimating the blood-brain barrier function.     

Electron spin resonance studies of manganese(II) and copper(II) salts of poly(ethylene-co-methacrylic acid)s

The ionic interaction of poly(ethylene-co-methacrylic acid) ionomer neutralized with Mn²⁺ or Cu²⁺ was studied by ESR spectroscopy to explore the local structure in the ionic aggregate. ESR spectra of the ethylene ionomer were obtained as functions of degree of neutralization and temperature. The existence of both isolated and aggregated cations in the ionomer was confirmed by ESR. In addition, the formation of a Cu²⁺?Cu²⁺ dimer structure similar to the crystal structure of copper acetate monohydrate was found in ethylene ionomer containing the Cu²⁺. Cation-cation interactions changed markedly around 70°C with increasing temperature, representing the onset of the motion of cations in the aggregated ionic structure.     

Total reactivity of pyridine and quinoline via the reactions of arylbenzoates with hydroxide ion. Apparent substituent constants for some N-heteroaromatic groups

A new set of apparent σ values was evaluated for the aza substitution of all positions in pyridyl and quinolyl groups on the basis of the alkaline hydrolysis of aryl benzoates. The enhanced reactivities of 4-pyridyloxy- and 4-quinolyloxy- groups were first estimated quantitatively.