Fast and Robust Nanocellulose Width Estimation Using Turbidimetry

The dimensions of nanocelluloses are important factors in controlling their material properties. The present study reports a fast and robust method for estimating the widths of individual nanocellulose particles based on the turbidities of their water dispersions. Seven types of nanocellulose, including short and rigid cellulose nanocrystals and long and flexible cellulose nanofibers, are prepared via different processes. Their widths are calculated from the respective turbidity plots of their water dispersions, based on the theory of light scattering by thin and long particles. The turbidity‐derived widths of the seven nanocelluloses range from 2 to 10 nm, and show good correlations with the thicknesses of nanocellulose particles spread on flat mica surfaces determined using atomic force microscopy.

     

Effectiveness of taurine in protecting biomembrane against oxidant

The effect of taurine in protecting biomembrane attacked by hypochlorous acid (HOCl) was examined using canine erythrocytes which had been pre-treated with HOCl. In the treatment, most of the HOCl was consumed as a result of its reaction with a number of electrophilic substances, such as free amino groups (-NH2) in the membrane, whereas hemoglobin inside the cells was not oxidized. The lysis of HOCl-treated erythrocytes was dependent on the concentration of HOCl and on the incubation time at 37 degrees C. Taurine inhibited the lysis at 37 degrees C in a dose dependent manner. During the incubation of HOCl-treated erythrocytes with taurine, an appreciable amount of monochlorotaurine (TauNHCl) was detected in the supernate. This suggests that taurine might remove the oxidized chlorine from HOCl-treated erythrocytes, resulting in the production of TauNHCl. The effect of taurine on the removal of Cl+ moiety was further examined using Sepharose gel with free amino groups. Taurine removed Cl+ moiety from HOCl-treated Sepharose gel, and the yield of TauNHCl depended on the concentration of taurine and the incubation time. These results indicate that taurine might inhibit the hemolysis by scavenging the oxidized chlorine moiety from the HOCl-treated erythrocytes. Inhibition of the HOCl-induced hemolysis was also observed with other amino acids.(ABSTRACT TRUNCATED AT 250 WORDS)     

Studies on cardiotonic agents. I. Synthesis of some quinazoline derivatives

A series of quinazoline derivatives with various 4-heterocyclylpiperidino groups at the 4-position was synthesized and tested for cardiotonic activity in anesthetized dogs. Among them, several 6,7-dimethoxyquinazoline derivatives showed potent cardiotonic activity.     

Induction of differentiation of human leukemia cells by various combinations of cytokines and low-molecular-weight inducers

To explore agents for differentiation therapy of leukemias, various combinations of cytokines and low-molecular-weight inducers were examined for differentiation-inducing activity toward three kinds of human leukemia-derived cell lines. The strongest differentiation inducing activity on promyelocytic HL60 cells and histiocytic U937 cells was obtained by combining recombinant tumor necrosis factor (rTNF), interferon-gamma (IFN-gamma), retinoic acid (RA), and 1 alpha,25-dihydroxyvitamin D3 (1 alpha,25(OH)2D3). For myeloblastic ML1 cells, the combination of rTNF, IFN-gamma, and RA had the strongest differentiation-inducing activity.     

Studies on cardiotonic agents. II. Synthesis of novel phthalazine and 1,2,3-benzotriazine derivatives

A series of phthalazine and 1,2,3-benzotriazine derivatives which have heterocyclylpiperidino groups was synthesized and tested for cardiotonic activity in anesthetized dogs. Several 6,7-dimethoxyphthalazine derivatives showed relatively potent cardiotonic activity comparable to that of amrinone.     

Chiral separation of trimetoquinol hydrochloride and related compounds by micellar electrokinetic chromatography using sodium taurodeoxycholate solutions and application to optical purity determination

The chiral separation of trimetoquinol hydrochloride, which is a bronchodilator (Inolin), and three related compounds by micellar electrokinetic chromatography was investigated using a bile salt as a chiral surfactant. Enantiomers of these compounds, except laudanosoline, were successfully separated within 12 min using a separation tube of effective length 500 mm × 0.05 rum i.d. and a 0.05 M sodium taurodeoxycholate solution of pH 7.0. The observed theoretical plate numbers of the peaks were ca. 150000. Chiral recognition was affected by the structure of bile salts, the pH of the buffer solutions used and the structure of the solutes. Of four kinds of bile salts, successful chiral separation was achieved only using sodium taurodeoxycholate solution under neutral conditions. The method was applied to the optical purity determination of trimetoquinol hydrochloride. The effects of surfactant concentrations and some additives to the micellar solution are briefly described.     

Synthesis of crown ether-terminated poly(methyl methacrylate) by radical chain transfer polymerization

Mercapto-16-crown-5 was prepared starting from tetraethyleneglycol and 3-chloro-2-chloromethyl-1-propene. Radical polymerization of methyl methacrylate was carried out in the presence of mercapto-16-crown-5 as a chain transfer agent to give crown ether-terminated poly(methyl methacrylate). The end crown group was characterized by IR and ¹H-NMR spectra. Sodium cation was selectively extracted by this crown-containing polymer. The molecular weight of the obtained polymer had influence upon the ability of extraction of sodium cation.     

Furopyridines. X. Synthesis of tricyclic heterocycles,furo[2,3-b:4,5-c']-, furo[3,2-b:4,5-c']-, furo[2,3-c:4,5-c']- and furo[3,2-c:4,5-c']dipyridine

This paper describes the synthesis of four tricyclic heterocycles, furo[2,3–6:4,5-c']- ( 5a ), furo[3,2-b:4,5-c']- ( 5b ), furo[2,3-c:4,5-c']- ( 5c ) and furo[3,2-c:4,5-c']dipyridine ( 5d ). Starting with 2-formylfuropyridines ( 1a-d ), β-(2-furopyridyl)acrylic acids 2a-d were obtained by condensing with malonic acid. The acrylic acids were converted to the acid azides by reaction with ethyl chloroformate and the subsequent reaction with sodium azide. Heating of the acid azides at 230–240° with diphenylmethane and tributylamine gave tricyclic pyridinones 3a-d , which were converted to the respective chloro derivatives 4a-d by reaction with phosphorus oxychloride. Reduction of the chloro compounds over palladium-charcoal yielded compounds 5a-d respectively. All the compounds 2 to 5 were characterized by elemental analysis and spectral data. The H and ¹³C nmr and electronic spectral features of the furodipyridines were discussed comparing with those of the parent furopyridines.     

Chemoenzymatic synthesis of (+)-totarol, (+)-podototarin, (+)-sempervirol, and (+)-jolkinolides E and D

The enzymatic resolution products [(1R,4aR,8aR)-1,2,3,4,4a,5,6,7,8,8a-decahydro-5,5,8a-trimethyl-2-oxo-trans-naphthalene-1-methanol-2-ethylene acetal (8aR)-7 (98% ee) and {acetate of (1S,4aS,8aS)-1,2,3,4,4a,5,6,7,8,8a-decahydro-5,5,8a-trimethyl-2-oxo-trans-naphthalene-1-methanol-2-ethylene acetal} (8aS)-9 (>99% ee)] obtained by the lipase-catalyzed enantioselective acetylation of (±)-7 in the presence of vinyl acetate as an acyl donor were converted to the ,β-unsaturated ketones (8aR)-6 and (8aS)-6, respectively. Concise syntheses of (+)-totarol 1, (+)-podototarin 2 and (+)-sempervirol 3 were achieved based on Michael reactions between (8aS)-6 and the appropriate β-keto ester followed by aldol condensation. The first chiral syntheses of (+)-jolkinolides E 4 and D 5 were achieved from (5R,10R,12R)-12-hydroxypodocarpa-8(14)-en-13-one 15 derived from (8aR)-6.     

Application of AMS <Superscript>14</Superscript>C measurements to criminal investigations

¹⁴C variations of atmospheric CO₂ as well as carbonaceous fraction of living materials, such as collagen from tooth and bone, tissue, skin, hair, nail, etc., of modern humans are influenced by ¹⁴C produced artificially by nuclear bomb tests in the atmosphere from late 1950s to early 1960s. By careful investigation of ¹⁴C concentration of tree rings and human body samples formed in this time intervals, we can establish a relationship of their ¹⁴C concentrations with calendar year. By applying this relation to a sample whose ¹⁴C concentration can be measured, we can estimate the formation age of the sample. In addition, sources of the chemicals that were used in some criminal cases can be possibly identified, by their carbon isotope ratios (¹³C/¹²C and ¹⁴C/¹²C). This method of age determination has been applied to a forensic study, i.e., two criminal cases of murder. For each case, by comparing the measured ¹⁴C abundances of several pieces of hair and one tooth (the third molar) from the body with the annual change on concentrations of bomb-produced ¹⁴C, the time of death of the body and the age of the victim were estimated. The estimated values were consistent with the real ones that were revealed by the confession of the real murderers.