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21.
Sardine oil was obtained by centrifugation of surimi wastewater without heating or chemical refining. This oil (CE) showed light yellow color and the peroxide value was less than 1.0 meq/kg. The main lipid class of CE was triacylglycerol (TG) (>99%). These features indicate that CE can be directly used as food materials without further purification. Commercial sardine oil (CO) is usually prepared via some kind of refining process with high temperature (250 degrees C) and chemical treatment. The comparative study on the physiological effects of these sardine oils (CE and CO) revealed that the dietary sardine oils were more effective in reducing abdominal fat pads, plasma total cholesterol, and TG levels of rats than was a soybean oil diet (control). Furthermore, these effects were greater in CE than CO, although there was little difference in the fatty acid composition of both oils. Although the main lipid class of CE was TG (>99%), CE was prepared by centrifugation from surimi waste and directly used as dietary fat without further purification. Therefore, CE may contain some kinds of minor components, which could be attributed to the higher physiological activity of CE. To reveal the involvement of the minor compounds in CE, we prepared TG from CE by column chromatography and measured its effect on lipid metabolism of rats. TG from CE also showed the reducing effects on abdominal fad pads and plasma lipid levels. The effect of TG from CE was almost the same as that of original CE, suggesting that the higher nutritional activity of CE than CO may not be due to the minor compounds in CE.  相似文献   
22.
To evaluate the effects of avian-derived N deposition on forest C and N status, we investigated quantity and quality of litterfall, and chemical quality and N transformations in the forest floor from five sites that had been exposed to waterbird breeding colonies to differing degrees. The highest litterfall input of 2.6 t ha?1 month?1 was observed in the forest stand (Site 2) where intense bird breeding activity had been observed. Litterfall C/N was highest at the control site (no breeding activity) and decreased as the colonization stages advanced. Nitrogen concentration in litterfall and the forest floor was higher at those sites (Sites 3 and 4) where bird breeding had ceased and which represented the 'post-colony' situation, and consequently C/N and lignin/N of forest floor decreased. NH4-N pool size in the forest floor was higher at Site 2, probably due to ongoing input and mineralization of bird excreta. Nitrification rate and percent nitrification were highest at Sites 3 and 4. From these results we conclude that study sites exposed to bird colonies show signs of N excess even after colonies are abandoned.  相似文献   
23.
Sex determination in the Drosophila germ line is regulated by both the sex of the surrounding soma and cell-autonomous cues. How primordial germ cells (PGCs) initiate sexual development via cell-autonomous mechanisms is unclear. Here, we demonstrate that, in Drosophila, the Sex lethal (Sxl) gene acts autonomously in PGCs to induce female development. Sxl is transiently expressed in PGCs during their migration to the gonads; this expression, which was detected only in XX PGCs, is necessary for PGCs to assume a female fate. Ectopic expression of Sxl in XY PGCs was sufficient to induce them to enter oogenesis and produce functional eggs when transplanted into an XX host. Our data provide powerful evidence that Sxl initiates female germline fate during sexual development.  相似文献   
24.
We removed approximately 100% of clathrated oxygen ions from the crystallographic cages in a single crystal of 12CaO.7Al2O3, leading to the formation of high-density (approximately 2 x 10(21) cm-3) electrons highly localized in the cages. The resulting electron forms a structure that we interpret as an F+ center and migrates throughout the crystal by hopping to a neighboring cage with conductivity approximately 100 siemens per centimeter, demonstrating that the encaged electron behaves as an anion. The electron anions couple antiferromagnetically with each other, forming a diamagnetic pair or singlet bipolaron. The resulting [Ca24Al28O64]4+(4e-) may be regarded as a thermally and chemically stable single crystalline "electride."  相似文献   
25.
The first stars fundamentally transformed the early universe by emitting the first light and by producing the first heavy elements. These effects were predetermined by the mass distribution of the first stars, which is thought to have been fixed by a complex interplay of gas accretion and protostellar radiation. We performed radiation-hydrodynamics simulations that followed the growth of a primordial protostar through to the early stages as a star with thermonuclear burning. The circumstellar accretion disk was evaporated by ultraviolet radiation from the star when its mass was 43 times that of the Sun. Such massive primordial stars, in contrast to the often-postulated extremely massive stars, may help explain the fact that there are no signatures of the pair-instability supernovae in abundance patterns of metal-poor stars in our galaxy.  相似文献   
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Fermi liquid theory, the standard theory of metals, has been challenged by a number of observations of anomalous metallic behavior found in the vicinity of a quantum phase transition. The breakdown of the Fermi liquid is accomplished by fine-tuning the material to a quantum critical point by using a control parameter such as the magnetic field, pressure, or chemical composition. Our high-precision magnetization measurements of the ultrapure f-electron-based superconductor β-YbAlB(4) demonstrate a scaling of its free energy that is indicative of zero-field quantum criticality without tuning in a metal. The breakdown of Fermi liquid behavior takes place in a mixed-valence state, which is in sharp contrast with other known examples of quantum critical f-electron systems that are magnetic Kondo lattice systems with integral valence.  相似文献   
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ABSTRACT

Cadmium (Cd) has an important impact on agriculture, as the excessive consumption of this element from contaminated food crops leads to toxicity in humans. Rice is the greatest source of dietary Cd intake in populations consuming rice as a staple food. Therefore, reducing the Cd concentration of rice grains for diminishing the potential risk of Cd for human health is a major challenge. This review summarizes the main achievements on Cd accumulation in rice by our research group. Using a positron-emitting tracer imaging system, we succeeded to visualize differences in real-time Cd dynamics from roots to panicles in rice varieties with different Cd accumulation abilities. Several loci or genes responsible for Cd accumulation in rice were found through quantitative trait loci (QTLs) analysis. Using the QTL qCdp7 responsible for efficiently extracting Cd from paddy soils, practical rice varieties for Cd-phytoextraction were developed by DNA marker-assisted breeding. A rice variety named ‘Koshihikari Kan No.1? carrying a mutant allele of OsNramp5 for reducing Cd concentration in rice grains was produced by mutant breeding with ion-beams, and breeding programs have been implemented to transfer this allele into many Japanese rice varieties by DNA marker-assisted breeding. Growing low-Cd varieties aerobically would be a feasible way to simultaneously reduce inorganic arsenic and Cd concentrations in rice grains. These results provide basis for reducing Cd concentration in rice through breeding new varieties.  相似文献   
30.
Fluid accumulation was induced in ligated intestinal loops of both pheasants and chickens injected with crude Clostridium botulinum C2 toxin. Necrosis of the epithelium and lamina propria of the duodenum and jejunum occurred in both species of bird after intraduodenal administration of crude C2 toxin. The severity of such reactions depended upon the dose and the period after administration of C2 toxin up to eight hours, and such reactions were suppressed specifically with rabbit anti-C2 toxin. These results confirm that C2 toxin is one of the causes of diarrhoea in avian botulism.  相似文献   
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