Although fish roes (or the egg-laden ovary) are seafood products with high nutritional value and are considered abundant in vitamins including vitamin B12, nevertheless, the detailed properties of vitamin B12 have not been fully elucidated in fish roe products. Vitamin B12 content was determined using C18-reversed-phase high-performance liquid chromatography after purification of samples from immunoaffinity columns. Salmon egg-laden ovary products (sujiko), salmon roe products (ikura), dried mullet roe products (bottarga), and white sturgeon roe products (caviar) were found to contain substantial levels of vitamin B12 (more than approximately 15 µg/100 g wet weight). Interestingly, high levels of vitamin B12 per 100 g wet weight have been measured in pollack roe products (tarako) and flying fish roe products (tobiko). Liquid chromatography–electrospray-ionization/tandem mass spectrometry analysis revealed that vitamin B12 was the predominant corrinoid in the evaluated fish roe products examined, while no inactive corrinoid compounds were identified. These results suggest that commercially available fish roe products could be an important source of vitamin B12 for use as a dietary product for humans.
In recent years, acid rain has been a social problem all over the world. In Japan, it is also a big problem especially in the metropolitan area. Then, we have measured major ions such as H+, Na+, NH4+, K+, Mg2+, Ca2+, Cl?, NO3?, and SO42? in precipitation and dry deposition samples which had been collected at 9 sampling sites at Hiyoshi, Mita, Kashiwa, Shiki, Fujisawa, Yokosuka, Mitaka, Hachiouji, and Ashikaga in Tokyo Metropolitan area for 10 years since 1990. The average pH of precipitation in their sites was 4.56 (n=1906). As the results of multiple regression analysis showed that pH of precipitation was determined by 5 ions such as NH4+, nssCa2+(non sea salt calcium), nssCl?(non sea salt chloride), NO3?, nssSO42?(non sea salt sulfate) in the most of the sampling sites. Therefore, it is very important to investigate the behavior of these ions to understand the acidification of rain in Tokyo Metropolitan area. In this study, a long term trend of each ion concentration in precipitation and wet deposition was also investigated the base on the data we had observed at 7 sites for 10 years by the statistical method. 相似文献
Nucleotide sequences in internal transcribed spacer (ITS)-1 region derived from dried nori products produced in Japan, China, and the Republic of Korea were compared. Thalli contained in the Japanese products were genetically homogenous, and their nucleotide sequences in ITS-1 were identical to those of the reference strains of Pyropia yezoensis f. narawaensis. In Chinese products, the thalli were related to P. yezoensis strain Minomiasakusa. In contrast, the thalli in the Korean products were genetically heterogeneous, and several different P. yezoensis strains and other Pyropia spp. were used for dried nori products. In some thalli produced in both China and Korea, the DNA sequences of the ITS-1 region were identical with that of Japan, suggesting that the cultivar strains might have been transplanted from Japan to China in recent years. The 432-bp-long nucleotide sequences in the ITS-1 region of thalli derived from Japanese origin were cleaved to two restriction fragments at 154 and 278 bp by cleavage of PCR-amplified products using MspI. Conversely, almost all of the corresponding sequences derived from China and Korea were lacking MspI or other restriction patterns, except for nori products from some areas that cultivate a closely related strain to the Japanese cultivar. 相似文献
Thermal insulation and warmth-keeping properties of thick plywood-faced sandwich panels with low-density fiberboard (plywood-faced
sandwich, PSW), which were developed as wood-based structural insulation materials for walls and floors, are comprehensively
clarified. The properties focused on were thermal conductivity (λ), thermal resistance (R), and thermal diffusivity (D). The results for PSW panels were compared with those for commercial wood-based boards, solid wood, and commercial insulators.
The λ values were measured for PSW panels and their core and face elements. As a result, the composite theory of λ was found to be appropriate for PSW composites, because the calculated/experimental λ ratios were approximately 90%. The λ values for PSW panels with densities of 340 kg/m3 (PSW350) and 410kg/m3 (PSW400) were 0.070 and 0.077W/mK, respectively. The R values for PSW350 and PSW400 were 1.4 and 1.2m2K/W, and the D values were 0.00050 and 0.00046m2/h, respectively. Consequently, the PSW provided thermal insulation properties superior to those of the boards and in terms
of warmth-keeping properties were greatly advantageous over the insulators. These advantages were due to the moderate densities
of PSW panels. The PSW panel with sufficient thickness showed remarkably improved thermal resistance compared with those of
the boards. 相似文献
Levels of the selenium-containing imidazole compound selenoneine and overall organic selenium were measured in the muscle
of fishes by speciation analysis. The method involves monitoring 82Se levels by liquid chromatography inductively coupled plasma mass spectroscopy using a gel filtration column. Selenoneine
levels were found to be highest in swordfish muscle (concentration 2.8 nmol/g tissue). The selenoneine contents of bigeye
tuna, Pacific bluefin tuna, albacore, yellowfin tuna, and alfonsino muscle were 1.3–2.6 nmol/g tissue. In muscle of these
fishes, most organic selenium (9–42%) was present as selenoneine. In other fish species, such as Pacific sardine, greeneye,
skipjack, Pacific mackerel, horse mackerel, red sea bream, and Japanese barracuda, selenoneine levels were 0.1–1.4 nmol/g
tissue, accounting for 3–34% of organic selenium. In contrast, muscle of Japanese conger, Japanese anchovy, chum salmon, Pacific
saury, white croaker, and marbled sole contained levels of selenoneine below the level of detection (<0.05 nmol/g tissue).
Mercury and selenium contents were 0.01–5.12 nmol/g tissue and 1.4–19.1 nmol/g tissue. The Se-to-Hg molar ratio varied from
species to species, ranging from 1 for swordfish to 217 for marbled sole. 相似文献
Several wood-based sandwich panels with low-density fiberboard core were developed for structural insulated walls and floors,
with different face material, panel thickness, and core density. The elastic moduli with and without shear effect (EL, E0) and shear modulus (Gb) were evaluated in four-point bending. Generally, the stiffer face, thicker panel, and higher core density were advantageous
in flexural and shear rigidity for structural use, but the weight control was critical for insulation. Therefore, optimum
designs of some virtual sandwich structures were analyzed for bending stiffness in relation to weight for fixed core densities,
considering the manufactured-panel designs. As a result, the plywood-faced sandwich panel with a panel thickness of 95 mm
(PSW-T100), with insulation performance that had been previously confirmed, was most advantageous at a panel density of 430
kg/m3, showing the highest flexural rigidity (ELI = 13 × 10−6 GNm2) among these panels, where EL, E0, and Gb were 3.5, 5.5, and 0.038 GN/m2, respectively. The panel was found to be closest to the optimum design, which meant that its core and face thickness were
optimum for stiffness with minimum density. The panel also provided enough internal bond strength and an excellent dimensional
stability. The panel was the most feasible for structural insulation use with the weight-saving structure. 相似文献