不同含水量下工具材料切向土壤黏附特性（摘选）

为了提高越野车辆性能和建筑、农业领域机械工作效率,就需要了解土壤黏附机理。该试验旨在找到不同工具材料的土壤切向黏附与含水率之间的关系,探讨土壤切向黏附对土壤剪切力学性能的影响。试验对橡胶（RUB）、钢（SS400）和树脂（PEEK）3种材料进行了直剪试验。结果表明,土壤和材料之间的切向黏附随着土壤含水量的增加而增加至最大值后降低。土壤切向黏附最大值的排序是钢（SS400）,其次是橡胶（RUB）,最后是树脂（PEEK）。结果还表明,3种材料道具与测试土壤间的外摩擦角随着土壤含水率的增加先降低后增加,当发生剪切的时候,随着剪切的发生,土壤含水量导致切向黏附的变化进而直接影响剪切应力和外摩擦角。      

Molecular cloning of two types of spiggin cDNA in the three-spined stickleback, Gasterosteus aculeatus

Two types of spiggin cDNAs were isolated from the three-spined stickleback. Northern blot analysis revealed that glue protein is composed of multiple spiggin molecules, and that their synthesis in kidney is strongly up-regulated by androgens.     

Changes in the nitrogen localized in the lamellae systems and stroma of rice chloroplast accompanying the stages of growth

The change in the nitrogen localized in the lamellae systems and stroma region of the rice chloroplast was pursued throughout the stages of growth and, further, the relationship between the composition of the chloroplast and leaf N content was examined. A common trend accompanying the stages of growth is recognized: that in the early stages of growth the amount of nitrogen existing as a form of stroma N is larger than that of lamellae N. Thereafter, stroma N tends to decrease in relation to lamellae N and finally, lamellae N becomes a dominant nitrogenous fraction in the chloroplast. The change in the composition of the chloroplast seems to be brought about by a change in the nitrogen metabolism of the chloroplast by which the distribution of absorbed nitrogen among the nitrogenous fractions of the chloroplast differs.     

Dietary phosphatidylinositol prevents the development of nonalcoholic fatty liver disease in Zucker (fa/fa) rats

Recent studies have shown that dietary phospholipids, especially phosphatidylcholine and phosphatidylserine, have various beneficial biological effects. However, there are not enough data concerning the physiological function of dietary phosphatidylinositol (PI). The metabolic syndrome, a cluster of metabolic abnormalities such as dyslipidemia, diabetes mellitus, and hypertension, is a widespread and increasingly prevalent disease in industrialized countries. Nonalcoholic fatty liver disease (NAFLD) is often associated with features of the metabolic syndrome. NAFLD describes the spectrum of liver damage ranging from hepatic steatosis to steatohepatitis, liver fibrosis, and cirrhosis, and it is emerging as the most common liver disease worldwide. The present study examined whether dietary PI protects Zucker ( fa/ fa) rats from the metabolic syndrome. For 4 weeks, rats were fed semisynthetic diets containing either 7% soybean oil or 5% soybean oil plus 2% PI. Dietary PI markedly prevented the development of hepatomegaly and hepatic steatosis and lowered hepatic injury markers in serum. Additionally, hyperinsulinemia was relieved by the feeding of dietary PI in Zucker rats. These effects were attributable to an increase in serum adiponectin, enhancement of fatty acid beta-oxidation, and suppression of mRNA expression of inflammatory genes in the liver. This is the first report that dietary PI increases serum adiponectin level and prevents the development of NAFLD in a rat model of the metabolic syndrome.     

Improvement of the functional properties of sucrose stearate by phosphorylation

Phosphorylated sucrose stearate (SE-P) was prepared by dry-heating sucrose stearate (SE) with metaphosphoric acid. The main product was deduced to be a monophosphosucrose monostearate by chemical analysis and mass spectrometry. SE-P exhibited remarkably higher solubility and emulsifying properties than SE, especially in the acidic region and in the presence of NaCl, and SE-P bound Ca2+ at a 1:1 molar ratio (SE-P/Ca2+). SE-P markedly reduced the viscosity of potato starch paste and inhibited retrogradation, whereas SE did not reduce it so much. It is thus expected that phosphorylation would be an appropriate method for improving the functional properties of SE and that SE-P could be used as a novel emulsifier and modifier with Ca2+-binding ability for starchy foods.     

Antioxidative properties of tripeptide libraries prepared by the combinatorial chemistry

Two series of combinatorial tripeptide libraries were constructed, based on an antioxidative peptide isolated from a soybean protein hydrolysate. One was a library of 108 peptides containing either His or Tyr residues. Another was a library of 114 peptides related to Pro-His-His, which had been identified as an active core of the antioxidative peptide. The antioxidative properties of these libraries were examined by several methods, such as the antioxidative activity against the peroxidation of linoleic acid, the reducing activity, the radical scavenging activity, and the peroxynitrite scavenging activity. Two Tyr-containg tripeptides showed higher activities than those of two His-containing tripeptides in the peroxidation of linoleic acid. Tyr-His-Tyr showed a strong synergistic effects with phenolic antioxidants. However, the tripeptide had only marginal reducing activity and a moderate peroxynitrite scavenging activity. Cysteine-containing tripeptides showed the strong peroxynitrite scavenging activity. Change of either the N-terminus or C-terminus of Pro-His-His to other amino acid residues did not significantly alter their antioxidative activity. Tripeptides containing Trp or Tyr residues at the C-terminus had strong radical scavenging activities, but very weak peroxynitrite scavenging activity. The present results allow us to understand why protein digests have such a variety of antioxidative properties.     

Effects of molybdenum application on the yield,nitrogen nutrition and nodule development of soybeans

Field experiments were conducted on a volcanic ash soil with low available Mo and moderate acidity for 4 years to determine thfc responses of soybeans and soybean nodules to Mo application with seed treatment.

Mo application resulted in a 15.7% increase in the average yield of the nodulated varieties over 4 seasons. However, the genetically controlled non-nodulating variety did not respond to Mo under the same experimental conditions. Nodulated plants treated with Mo became increasingly greener from the pre-bloom stage and contained much more N in their tops during the later period of growth and accumulated considerably larger amount of N in seeds produced per unit area. These results are in agreement with the enhancement of N, fixing activity per plant basis during a long period covered from the stage of 2nd trifoliate leaf unfolding to that of seed development. The increase of yield obtained by the Mo application is ascribed to the improvement of N, fixing activity of the root nodules, The enhancement of N, fixing activity was mainly due to a higher activity per unit nodule weight at early itaget and was due to better growth of nodules during the latter half of growth. Nodules on Mo-created plants were characteristically larger size, had lower water contcnt and higher Mo content.

Referring to the data presented by the authors and several other investigators on available Mo in soils, soil pit, and other related factors, discussion is made that the yield response of soybeans to Mo application is expected in a good number of fields in Japan as a result of nodule response leading to the enhancement of symbiotic N, fixation throughout growth.     

Changes in polyphenolic content and radical-scavenging activity of sweet potato (Ipomoea batatas L.) during storage at optimal and low temperatures

Polyphenolic content and radical-scavenging activities (RSA) of four sweet potato (Ipomoea batatas L.) cultivars were characterized after storage at optimal (15 degrees C) or low temperature (5 degrees C) for 0, 13, 26, and 37 days. The polyphenolic content increased during storage in three cultivars but not in 'Murasakimasari'. The change in 1,1-diphenyl-2-picrylhydrazyl radical-scavenging activity (DPPH-RSA) correlated very well with polyphenolic content. The increases in polyphenolics and the RSA in 'Benimasari' were significantly greater during storage at 5 degrees C than at 15 degrees C. The main polyphenolic components in all cultivars were chlorogenic acid (ChA) and 3,5-di-O-caffeoylquinic acid (3,5-diCQA). ChA level increased more at 5 degrees C than at 15 degrees C, whereas that of 3,5-diCQA was greater at 15 degrees C. Caffeoylquinic acids and RSA in 'Murasakimasari', which contains a large amount of anthocyanin in flesh tissue, were extremely high at the beginning of storage and remained nearly constant or decreased over time. A non-caffeoylquinic acid component that increased during storage, especially in 'J-Red' at 15 degrees C, was purified by successive chromatographic steps. The isolate was identified as caffeoyl sucrose [CSu, 6-O-caffeoyl-(beta- d-fructofuranosyl-(2-->1))-alpha-D-glucopyranoside] by fast atom bombardment-mass spectroscopy (FAB-MS), infrared spectroscopy (IR), and nuclear magnetic resonance spectroscopy (NMR). These results suggest that storage under cultivar-dependent, controlled temperature is one approach for increasing desirable physiologic function associated with RSA of polyphenolic compounds in sweet potato roots.     

Asphericity in supernova explosions from late-time spectroscopy

Core-collapse supernovae (CC-SNe) are the explosions that announce the death of massive stars. Some CC-SNe are linked to long-duration gamma-ray bursts (GRBs) and are highly aspherical. One important question is to what extent asphericity is common to all CC-SNe. Here we present late-time spectra for a number of CC-SNe from stripped-envelope stars and use them to explore any asphericity generated in the inner part of the exploding star, near the site of collapse. A range of oxygen emission-line profiles is observed, including a high incidence of double-peaked profiles, a distinct signature of an aspherical explosion. Our results suggest that all CC-SNe from stripped-envelope stars are aspherical explosions and that SNe accompanied by GRBs exhibit the highest degree of asphericity.