Polyolefin fibers with chemically fixed active ester for the solid phase synthesis of an amide derivative

Reactive fibers having chemically fixed active ester were derived from chloromethylstyrene grafted polyethylene-coated polypropylene staple fiber and non-woven cloth. First, chlorine atoms in each fiber were substituted by mercapto groups, and the resulting fibers were reacted with N-hydroxymaleimide to obtain fibers containing chemically fixed N-hydroxysuccinimide moieties. These fibers were converted into reactive fibers having chemically fixed active ester by reaction with a model carboxylic acid (3-(2-bromophenyl)propionic acid) in the presence of a condensing reagent (1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride) in excess. Performances of both reactive fibers in the model amide synthesis were compared by their reaction with 2-phenylethylamine. Although the reactive non-woven cloth gave an amide contaminated with unknown organic impurities, the reactive staple fiber yielded highly pure product. Possible causes of this difference are discussed on the basis of SEM observation of both fibers.     

Inhibition of cholesterol absorption by (−)N-[α-phenyl-β-(p-tolyl) ethyl] linoleamide in rats

The effect of (−)N-[α-phenyl-β-(p-tolyl)ethyl] linoleamide (PTLA) on intestinal absorption of cholesterol was studied in rats. Oral administration of 15 mg PTLA to rats resulted in a significant (P<0.05) decrease in the radioactivity in serum and liver 4 hr after administration of labeled cholesterol. The effect of PTLA was greater on the absorption of cholesteryl oleate as compared with free cholesterol. The rate of hydrolysis of cholesteryl oleate in mucosal homogenates of rat intestine was decreased with PTLA, suggesting that the inhibition of cholesterol absorption by PTLA is related to its effect on cholesteryl ester hydrolysis in the intestine.     

Electric-field-induced strain in Mn-doped KNbO3 ferroelectric ceramics

Potassium niobate, KNbO₃ (KN), ceramics doped with manganese (Mn) were prepared by a modified conventional ceramic fabrication process to characterize their dielectric, ferroelectric and electrostrain properties. In this study, 0.22% of a large electric-field-induced strain was obtained at 80 kV/cm under unipolar driving for 1.2 wt% MnCO₃-doped KN ceramics. Basically, it is difficult to obtain dense and nondeliquescent KN ceramics by the conventional method because of potassium ions. The key factor in obtaining dense and nondeliquescent KN ceramics is the calcination process control. Thus, the two-step calcination pattern is proposed for this purpose. Dense, nondeliquescent and high-resistivity Mn-doped KN ceramics were obtained, resulting in a large electric-field-induced strain under a high electric field.     

Lattice misorientation at domain boundaries in β-Ga2O3 single-crystal substrates observed via synchrotron radiation X-ray diffraction imaging and X-ray reticulography

To evaluate the lattice misorientation at domain boundaries (DBs) in β-Ga₂O₃, we performed X-ray diffraction imaging (XRDI), X-ray reticulography (XRR), and X-ray topography (XRT) using a synchrotron radiation light source. Four reciprocal lattice vectors ( g -vectors) were applied, and the DBs showed different visibilities in the XRDI maps depending on the g -vector. By analyzing possible characteristics of the misorientation, the XRDI results suggested that the DB being investigated was associated with a misorientation on the ($\overline{10}05$) plane and contained twist and tilt components. The apparent peak change in XRDI caused by the two components was calculated. We further succeeded in separating the tilt and twist components using XRR images in conjunction with simulation. Dislocation arrays at the DBs were observed using XRT, and the average distance between the dislocations in the array was consistent with the misorientation obtained using XRDI and XRR. The distribution of DBs across a wide area was acquired by a combination of XRR images recorded on a charge-coupled device camera and X-ray films. The fringe-patterned XRR on X-ray films provided a powerful and nondestructive tool to characterize DBs distributed across a large-diameter wafer with an angular resolution on the order of several arc sec (low 10⁻⁵ rad).     

Digestibility of Sweet Potato Raw Starches by Glucoamylase

Three crude glucoamylase preparations from Rhizopus sp., Chalara paradoxa and Aspergillus sp. K-27 were used to determine the digestibility of raw starches from eight sweet potato varieties. Granule sizes and amylose contents were also measured. The average granule sizes ranged between 10.5 and 14.2 μm. The amylose contents varied between 18.2 and 21.8%. The hydrolysis rates for the raw starches by any of the three glucoamylases were similar. However, starch of the variety Hi-starch had a slightly lower hydrolysis rate than other starches when Rhizopus sp, enzyme was used.     

Chemical Composition of Cell Wall Material from Sweet Potato Starch Residue

Cell wall material was isolated from the residue obtained after the extraction of sweet potato starch by treatment with the α-amylase. The wall material was fractionated by successive extraction with various reagents. The pectic substance was mainly composed of uronic acid (47.1%) residues and contained galactose as the predominant neutral sugar residues. The hemicellulosic fraction was further fractionated by precipitation with iodine in the presence of calcium chloride to give two fractions, a iodine precipitatable-iodine complex (HC-IP) and a supernatant solution (HC-IS). The HC-IS fraction had a higher glucose content (53.4%), whereas the HC-IP fraction had a high content of xylose residues (35.1%). The HC-IP fraction consisted mainly of xylan, as judged by the degradation with purified xylanase.