Electrical properties of sintered EuZrO3  EuNbO3 and EuNbO3

Electrical resistivity of two-phase products [yEuZrO₃ + (1 ? y) EuNbO₃] increased continuously with y, and a transition from a metallic to semiconducting characteristic occured at y = 0.14. The resistivity varied almost linearly with temperaure in the range y = 0 to y = 0.24, and thermal coefficients of resistivity at 300 K for the products decreased from +5.9 × 10^?4 K^?1 to ?7.4 × 10^?4 K^?1 according to the value of y. At y = 0.14, the thermal coefficient was almost zero. Thermal coefficients of electrical resistivity for the niobates with various oxygen contents were all positive in the range $\text{2.55 <}\text{O}\text{Nb}\text{< 3.24}$ and exhibited a sharp minimum at $\text{O}\text{Nb}\text{= 2.92}$. In all these niobates, Eu_xNbO₃ was a major phase and Eu₃NbO₆ or EuNbO₂ was detected as a second phase in the range $\text{O}\text{Nb}\text{> 3}$ or $\text{O}\text{Nb}\text{< 3}$ respectively. Peaks in the resistivity curves were correlated with a magnetic ordering temperature for samples with an overall ratio $\text{O}\text{Nb}\text{> 3}$.     

Electrical properties of sintered EuTiO3  EuNbO3

Two-phase sintered products [yEuTiO₃ + (1?y)EuNbO₃] were investigated as electrical-resistor materials. Electrical resistivities of the products did not depend on y in the range 0 < y < 0.96, and rapidly increased with increasing y over y = 0.96. The sintered products were metallic conductors from y = 0 to y = 0.96, and were semiconductors at y > 0.96. Thermal coefficients of resistivity for sintered products varied continuously with y, and became a maximum of 2.8 × 10^?3 K^?1 at y = 0.75 and a minimum around y = 1.00. The coefficient was positive at y < 0.96 and negative at y > 0.96. The absolute value of the thermal coefficient of resistivity minimized, namely ($\text{1}\text{?}$) ($\text{d}\text{?}\text{dT}\text{) = 0}$, at y = 0.96.     

循环荷载下砂质混合土孔隙水压力特性研究

通过对各种细颗粒含量的土实施从小到大应变水平的动力循环荷载试验,采用累积损失能量的观点,分别考察了土的细颗粒成分含量、围压、加载频率、加载形式及荷载的不规则性对孔压的影响,提出了孔隙水压力和累积损失能量的归一化方法,建立了砂质混合土的孔隙水压力上升模型,并探讨了模型参数和土的细颗粒成分含量的关系。     

Unusual Fatty Acids in the Fat Body of the Early Nesting Bumblebee, <Emphasis Type="Italic">Bombus pratorum</Emphasis>

Unusual fatty acids with 24, 26, and 28 carbon atoms were found in triacylglycerols (TAGs) isolated from fat body tissue of bumblebee Bombus pratorum. The most abundant one was (Z,Z)-9,19-hexacosadienoic acid. Its structure was determined by mass spectrometry after derivatization with dimethyl disulfide and by infrared spectroscopy. ECL (equivalent chain length) values of its methyl ester were determined on both DB-1 and DB-WAX capillary columns. (Z,Z)-9,19-Hexacosadienoic acid is quite rare in nature. So far it has been identified only in marine sponges, and this work is the first evidence of its occurrence in a terrestrial organism. HPLC/MS analysis of the bumblebee TAGs showed that (Z,Z)-9,19-hexacosadienoic acid is present in one third of all TAG molecular species. As it was found in all sn-TAG positions, it is likely that (Z,Z)-9,19-hexacosadienoic acid is transported to tissues. Interestingly, labial gland secretion of B. pratorum was found to contain (Z,Z)-7,17-pentacosadiene, a hydrocarbon with markedly similar double bond positions and geometry. Possible biosynthetic relationships between these two compounds are discussed.     

Monitoring of the multiple bacteriocin production by Enterococcus faecium NKR-5-3 through a developed liquid chromatography and mass spectrometry-based quantification system

Enterococcus faecium NKR-5-3 produces four antimicrobial peptides referred here as enterocins NKR-5-3A, B, C and D. A two-step electrospray ionization-liquid chromatography and mass spectrometry (ESI-LC/MS)-based quantification system was developed to monitor its multiple bacteriocin production profiles, which is essential in understanding the complex production regulation mechanism of strain NKR-5-3. The developed ESI-LC/MS-based quantification system can easily monitor the multiple bacteriocin production of this strain. Using the developed system, the production of enterocin NKR-5-3B was found to be not as variable as those of the other enterocins in different cultivation media. Production of enterocin NKR-5-3B was also found to have a wider optimum incubation temperature (20-30°C) than enterocins NKR-5-3A, C and D (25°C). Furthermore, at least 2?nM of the bacteriocin-like inducing peptide, enterocin NKR-5-3D, regulated the production of NKR-5-3 enterocins except enterocin NKR-5-3B. These findings taken together suggest that enterocin NKR-5-3B has an independent production regulation mechanism from the other NKR-5-3 enterocins. The developed system could effectively pin-point the production profiles of the multiple bacteriocins of E.?faecium NKR-5-3 under different fermentation conditions.     

Production of dipeptidyl peptidase IV inhibitory peptides from defatted rice bran

The insulinotropic hormone glucagon-like peptide-1 is metabolised extremely rapidly by the ubiquitous enzyme dipeptidyl peptidase IV (DPP-IV). Therefore, human DPP-IV is a key regulator involved in the prevention and treatment of type 2 diabetes. To simplify the method of producing an inhibitory peptide against DPP-IV, we focused on rice bran (RB) as a source and subjected proteins from defatted RB to enzymatic proteolysis using 2 commercial enzymes. The RB peptides produced with Umamizyme G exhibited 10 times the inhibitory activity as those produced with Bioprase SP. The half-maximal inhibitory concentration (IC₅₀) value of the RB peptides was 2.3 ± 0.1 mg/ml. Leu-Pro and Ile-Pro were identified as the inhibitory peptides among the RB peptides produced with Umamizyme G. Ile-Pro was the strongest DPP-IV inhibitor among the 15 Xaa-Pro dipeptides and Pro-Ile tested. Ile-Pro competitively inhibited DPP-IV (K_i = 0.11 mM). Mass spectrometry indicated that the contents of Leu-Pro and Ile-Pro in the RB peptides were 2.91 ± 0.52 μg/mg.     

Studies on the Dehydrogenative Polymerizations of Monolignol β‐Glycosides. Part 1. Syntheses of Monolignol β‐glycosides, (E)‐Isoconiferin, (E)‐Isosyringin,and (E)‐Triandrin

Abstract

(E)‐4‐O‐Acetyl coniferyl alcohol was synthesized by the reduction of (E)‐4‐O‐acetyl ferulic acid with sodium borohydride and N,N‐dimethylchloromethylenium chloride in 80.2% yield. The glycosylation of (E)‐4‐O‐acetyl coniferyl alcohol with trichloroacetimidoyl 2,3,4,6‐tetra‐O‐pivaloyl‐α‐D‐glucopyranoside in the presence of BF₃-Et₂O in anhydrous CH₂Cl₂, followed by deacylation gave (E)‐isoconiferin in high yield. This synthetic method could be applied to the syntheses of other monolignol β‐glycosides. As a result, (E)‐isoconiferin, (E)‐isosyringin, and (E)‐triandrin were synthesized from vanillin, syringaldehyde, and p‐hydroxybenzaldehyde, respectively, by five reaction steps in high overall yield.     

Site-Specific Fracture Healing: Comparison between Diaphysis and Metaphysis in the Mouse Long Bone

The process of fracture healing varies depending upon internal and external factors, such as the fracture site, mode of injury, and mechanical environment. This review focuses on site-specific fracture healing, particularly diaphyseal and metaphyseal healing in mouse long bones. Diaphyseal fractures heal by forming the periosteal and medullary callus, whereas metaphyseal fractures heal by forming the medullary callus. Bone healing in ovariectomized mice is accompanied by a decrease in the medullary callus formation both in the diaphysis and metaphysis. Administration of estrogen after fracture significantly recovers the decrease in diaphyseal healing but fails to recover the metaphyseal healing. Thus, the two bones show different osteogenic potentials after fracture in ovariectomized mice. This difference may be attributed to the heterogeneity of the skeletal stem cells (SSCs)/osteoblast progenitors of the two bones. The Hox genes that specify the patterning of the mammalian skeleton during embryogenesis are upregulated during the diaphyseal healing. Hox genes positively regulate the differentiation of osteoblasts from SSCs in vitro. During bone grafting, the SSCs in the donor’s bone express Hox with adaptability in the heterologous bone. These novel functions of the Hox genes are discussed herein with reference to the site-specificity of fracture healing.