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91.
Yukie Tada Norio Yano Hiroshi Takahashi Katsuhiro Yuzawa Hiroshi Ando Yoshikazu Kubo Akemichi Nagasawa Akio Ogata Dai Nakae 《Journal of toxicologic pathology》2012,25(4):233-239
Iron nanomaterials are of considerable interest for application to
nanotechnology-related fields including environmental catalysis, biomedical imaging, drug
delivery and hyperthermia, because of their superparamagnetic characteristics and high
catalytic abilities. However, information about potential risks of iron nanomaterials is
limited. The present study assessed pulmonary responses to a single intratracheal spray
instillation of triiron tetraoxide nanoparticles (magnetite) in rats. Ten-week-old male
and female Fischer 344 rats (n=5/group) were exposed to a single intratracheal spray
instillation of 0 (vehicle), 5.0, 15.0 or 45.0 mg/kg body weight (BW) of magnetite. After
14 days, the rats were sacrificed, and biological consequences were investigated. The lung
weights of the 15.0 and 45.0 mg/kg BW male and female groups were significantly higher
than those of the control groups. The lungs of treated rats showed enlargement and black
patches originating from the color of magnetite. The typical histopathological changes in
the lungs of the treated rats included infiltration of macrophages phagocytosing
magnetite, inflammatory cell infiltration, granuloma formation and an increase of goblet
cells in the bronchial epithelium. The results clearly show that instilled magnetite
causes foreign body inflammatory and granulating lesions in the lung. These pulmonary
responses occur in a dose-dependent manner in association with the increase in lung
weight. 相似文献
92.
Seo JP Tsuzuki N Haneda S Yamada K Furuoka H Tabata Y Sasaki N 《Research in veterinary science》2012,93(3):1481-1486
A three dimensional scaffold is essential in mesenchymal stem cells (MSCs) delivery in cell-based therapy for facilitating cell adherence, migration, proliferation, and differentiation. The objectives of this study were to evaluate the possibility of β-tricalcium phosphate incorporated gelatin sponges (Gelatin/β-TCP sponge) as scaffolds for equine MSCs and to examine the effects of seeding density and seeding method on the proliferation of equine MSCs in the Gelatin/β-TCP sponges. Mononuclear cells and MSCs isolated from bone marrow were seeded into Gelatin/β-TCP sponges at different densities by different seeding methods-static or agitated methods. Proliferation of the MSCs in Gelatin/β-TCP was assessed using the Cell Counting Kit-8 assay and histological examination. Distribution and proliferation of MSCs in the Gelatin/β-TCP sponge were observed, and the Gelatin/β-TCP sponge supported limited growth when seeded at high density. We also found that the agitated seeding method enhanced the proliferation of MSCs. This study demonstrated the suitability of Gelatin/β-TCP sponges for the proliferation and maintenance of equine MSCs. These results contribute to the application of MSC-seeded Gelatin/β-TCP sponges in equine medicine. 相似文献
93.
Simple, rapid cleanup method for analysis of aflatoxins and comparison with various methods 总被引:1,自引:0,他引:1
H Kamimura M Nishijima K Yasuda H Ushiyama S Tabata S Matsumoto T Nishima 《Journal of the Association of Official Analytical Chemists》1985,68(3):458-461
A method is described for simple and rapid determination of aflatoxins in corn, buckwheat, peanuts, and cheese. Aflatoxins were extracted with chloroform-water and were purified by a Florisil column chromatographic procedure. Column eluates were concentrated and spotted on a high performance thin layer chromatographic (HPTLC) plate, which was then developed in chloroform-acetone (9 + 1) and/or ether-methanol-water (94 + 4.5 + 1.5) or chloroform-isopropanol-acetone (85 + 5 + 10). Each aflatoxin was quantitated by densitometry. The minimum detectable aflatoxin concentrations (micrograms/kg) in various test materials were 0.2, B1; 0.1, B2; 0.2, G1; 0.1, G2; and 0.1, M1. Recoveries of the aflatoxins added to corn, peanut, and cheese samples at 10-30 micrograms/kg were greater than 69% (aflatoxin G2) and averaged 91%, B1; 89%, B2; 91%, G1; 78%, G2; and 92%, M1. The simple method described was compared with the AOAC CB method, AOAC BF method, and AOAC milk and cheese method. These methods were applied to corn, peanut, and cheese composites spiked with known amounts of aflatoxins, and to naturally contaminated buckwheat and cheese. Recoveries were much lower for the BF method compared with our simple method and the CB method. 相似文献
94.
Heckenberger MJ Kuikuro A Kuikuro UT Russell JC Schmidt M Fausto C Franchetto B 《Science (New York, N.Y.)》2003,301(5640):1710-1714
Archaeology and indigenous history of Native Amazonian peoples in the Upper Xingu region of Brazil reveal unexpectedly complex regional settlement patterns and large-scale transformations of local landscapes over the past millennium. Mapping and excavation of archaeological structures document pronounced human-induced alteration of the forest cover, particularly in relation to large, dense late-prehistoric settlements (circa 1200 to 1600 A.D.). The findings contribute to debates on human carrying capacity, population size and settlement patterns, anthropogenic impacts on the environment, and the importance of indigenous knowledge, as well as contributing to the pride of place of the native peoples in this part of the Amazon. 相似文献
95.
Katsube T Tabata H Ohta Y Yamasaki Y Anuurad E Shiwaku K Yamane Y 《Journal of agricultural and food chemistry》2004,52(8):2391-2396
Oxidation of low-density lipoprotein (LDL) has been implicated in atherogenesis. Antioxidants that prevent LDL from oxidizing may reduce atherosclerosis. This study investigated LDL antioxidant activity in edible plant products for development of dietary supplementation to prevent atherosclerosis. Fifty-two kinds of edible plants were extracted using 70% aqueous ethanol solution, and the antioxidant activity of the extracts, which inhibit human LDL oxidation induced by copper ion, was determined on the basis of the oxidation lag time and represented as epigallocatechin 3-gallate equivalent. 1,1-Diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and total phenolic content were also measured for comparisons with antioxidant activity in LDL. Plant products showing the greatest activity in LDL oxidation assay were akamegashiwa (Mallotus japonicus) leaf, Japanese privet (Ligustrum japonicum) leaf, green tea [Camellia sinensis (L.) O. Kuntze], and astringent persimmon (Diospyros kaki). The present study revealed high levels of LDL antioxidant activity in plant products for which such activity levels are underestimated in the DPPH radical scavenging assay and Folin-Ciocalteu assay. 相似文献
96.
Hiroaki Somura Hajime Tanji Koshi Yoshida Osamu Toda Katsuhiro Higuchi 《Paddy and Water Environment》2005,3(3):177-186
Efficient management of water resources in paddy fields requires an understanding of the volume of supplementary water used.
However, quantifying the volume is laborious due to the large amount of data that must be collected and analyzed. The purpose
of our study was to estimate the volume of supplementary water used in paddy fields, based on several years of available statistical
data, and to provide information on how much water can be supplied to paddy fields in each target area. In this study, the
lower Mekong River basin of northeast Thailand, Laos, and Cambodia was selected as the study area. In the first step, we used
agricultural statistics for each country, rainfall data acquired from the Mekong River Commission Secretariat (MRCS), and
the value of virtual water required per unit of rice production. Because several years of data were used for dry season harvested
areas and rice production in each country, the supplementary water to paddy fields in each province was calculated using virtual
water and rainfall. This method made it possible to estimate changes in supplementary water in each province. Through this
study, the supplementary water to paddy fields during the dry season in three countries was approximated from the minimum
number of data sets. Moreover, for cases in which it is not possible to procure agricultural water use data for a hydrological
model simulation, an alternative solution is proposed. 相似文献
97.
Murata S Sasaki K Kishimoto T Niwa S Hayashi H Takahama Y Tanaka K 《Science (New York, N.Y.)》2007,316(5829):1349-1353
Proteasomes are responsible for generating peptides presented by the class I major histocompatibility complex (MHC) molecules of the immune system. Here, we report the identification of a previously unrecognized catalytic subunit called beta5t. beta5t is expressed exclusively in cortical thymic epithelial cells, which are responsible for the positive selection of developing thymocytes. Although the chymotrypsin-like activity of proteasomes is considered to be important for the production of peptides with high affinities for MHC class I clefts, incorporation of beta5t into proteasomes in place of beta5 or beta5i selectively reduces this activity. We also found that beta5t-deficient mice displayed defective development of CD8(+) T cells in the thymus. Our results suggest a key role for beta5t in generating the MHC class I-restricted CD8(+) T cell repertoire during thymic selection. 相似文献
98.
The shattering habit in buckwheat occurs because of brittle or weak pedicels. Brittle pedicels are observed in wild buckwheat
but not in cultivated buckwheat. Using 2 self-compatible lines, 01AMU2 with brittle pedicels and Kyukei SC2 (KSC2) with non-brittle
pedicels, produced by an interspecific cross between Fagopyrum esculentum cv Botansoba (non-brittle) andF. homotropicum (brittle), we investigated the inheritance of brittle pedicels. F1 plants derived from crosses between Botansoba × 01AMU2 and Botansoba × KSC2 had brittle pedicels. The F2 population derived from the cross between Botansoba × 01AMU2 showed segregation of brittle and non-brittle pedicels that
fit the expected 3:1 ratio, suggesting that non-brittle pedicel in Botansoba is controlled by a single recessive gene (sht1). Another F2 population, derived from the cross between Botansoba × KSC2, showed segregation of brittle and non-brittle pedicels that
fit an expected ratio of 9:7,suggesting that non-brittle pedicel in KSC2is controlled by a different single recessive gene
(sht2). Thus, brittle pedicel is achieved by 2 complementary genes Sht1 and Sht2. The sht1 locus is linked to the S locus with a recombination frequency of5.46±1.18 (%). We investigated whether common buckwheat has the allele sht2by crossing 6 common buckwheat lines withKSC2. An analysis of the preliminary data showed that some of the F1 had brittle pedicels and others had non-brittle pedicels, suggesting that some common buckwheat lines possess both the allelesSht2 and sht2.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
99.
Kasumi Ito Yumi Oura Hiroyuki Takeya Shigeaki Hattori Katsuhiro Kitagawa Dinesh Paudel Govindra Paudel 《Journal of Forest Research》2005,10(6):453-463
Despite high expectations of nongovernmental organizations (NGOs) as project partners in bilateral-aid community forestry
(CF) projects in Nepal, it remains unclear whether the NGO involvement favored by donors is efficient. This study examined
the influence of NGOs on local people's perceptions of CF management by using a quantitative analysis based on a questionnaire
survey. Three different forest user groups (FUGs) supported by the Nepal Swiss Community Forestry Project were selected from
the Dolakha and Ramecchap districts: an FUG supported by another FUG acting as an NGO, an FUG supported by an NGO specializing
in CF, and an FUG without NGO support. A structured survey examined the perception of CF management based on satisfaction,
involvement, and self-reliance in 244 selected households belonging to the three FUGs. Knowledge of CF and personal information
was also surveyed and analyzed. The results showed that NGO involvement influences factors such as self-reliance and knowledge
of CF. FUG members who were supported by an NGO or an FUG had a significantly higher perception with respect to self-reliance
and knowledge than did members without such support. This indicates that experienced FUGs can serve as adequate service providers
for the CF formation procedure, in a manner similar to that of NGOs. On the other hand, the limited support from NGOs or FUGs
during the formation process seemed insufficient to fulfill the expectations of aid agencies with respect to the enhancement
of satisfaction and active participation on the part of FUG members. If aid agencies expect NGOs and FUGs to enhance the satisfaction
and participation of members, these intermediary organizations should be assigned to support more CF activities than just
the formation procedure. Aid agencies should take responsibility for strengthening the capabilities of NGOs and FUGs, as needed. 相似文献
100.
Ken’ichi Osaka Yasuhiro Nakajima Katsuhiro Suzuki Sadao Eguchi Hidetaka Katou 《Soil Science and Plant Nutrition》2013,59(5):558-565
ABSTRACTQuantitative evaluation of denitrification by the dual isotope approach, which measures the stable isotope ratios of nitrogen (δ15N) and oxygen (δ18O) in nitrate, has been hampered by the wide range of values reported for the ratio of enrichment factors for 15N and 18O (15ε and 18ε, respectively) during denitrification. The objectives of this study were to determine 15ε and 18ε values at different denitrification rates under controlled conditions, and to infer possible mechanisms by which the 18ε/15ε ratio is influenced under different conditions. Column experiments were conducted at 25, 15, and 10°C, which enabled determination of 15ε and 18ε at different denitrification rates, in the absence of nitrate replenishment from ammonium oxidation and other sources. The values of 15ε and 18ε ranged from ?11.8 to ?14.9‰ and from ?8.4 to ?15.9‰, respectively, with 15ε less sensitive to changes in the denitrification rates. The resultant 18ε/15ε ratio, ranging from 0.70 to 1.17, was close to the values reported for sediment incubations, and larger than those for groundwater systems. These results are consistent with the explanations that 18ε/15ε value itself is close to unity during denitrification, and that at smaller denitrification rates, concurrent reactions including re-oxidation of nitrite to nitrate lead to smaller apparent fractionation of 18O and smaller 18ε/15ε ratios. This suggests that while linear relationships between δ18O and δ15N give a strong evidence of denitrification, apparent 18ε/15ε values are site specific and depend on the ambient conditions. In evaluating denitrification in such systems, we suggest the use of 15ε in preference to 18ε because 15ε is less sensitive to denitrification rates. 相似文献