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71.
72.
Investigation of physicochemical form of uranium in sediment of brackish Lake Obuchi using sequential extraction procedure 总被引:1,自引:0,他引:1
The physicochemical form of uranium (238U) in the sediment of brackish Lake Obuchi was investigated using the standard procedures of sequential extraction. Approximately
60% to 70% of 238U was composed of the form bound to carbonates and iron (Fe)-manganese (Mn) oxides in silty sediments, whereas more than 50%
of 238U existed in the minerals of sandy sediments. The proportions of 238U bound to carbonates in the sediments of brackish Lake Obuchi were larger than those in fresh-water lake sediments. Most
of the uranium in the brackish lake sediment was considered to be mainly influenced by UO2(CO3)3
4− in seawater, judging from the fact that the 234U/ 238U activity ratios (1.13 to 1.16) of silty sediments were very close to that of seawater (1.14). The high correlation found
between the 238U concentration in the sediment and the amount of organic matter demonstrated that organic matter acts as a scavenger for
238U accumulation on the lake bottom.
Received: July 2, 1999 / Accepted: May 25, 2000 相似文献
73.
Fluctuations in the salinity and physicochemical characteristics of water quality were surveyed in brackish Lake Obuchi on
the Shimokita Peninsula in Aomori, Japan. The mean salinity in the surface layer in all regions of Lake Obuchi was about 10
psu, whereas in the basin region at depths of greater than 3 m it was 20 psu. Furthermore, all the year round the halocline
was formed at depths of 1–4 m. The maximum density gradient along a vertical axis in the center of the lake was observed at
depths of 1–2 m in summer and 2–4 m in spring and fall. The depth of the maximum density gradient fluctuated with the seasons.
In summer the water in the bottom layer was anoxic, and Fe, Mn, PO4
3−-P, and NH4
+-N supplied from the bottom sediment accumulated at high concentrations below the halocline. Thus, it was observed that the
transfer of substances between the layers above and below the barrier formed by the halocline is suppressed. Although Lake
Obuchi is small and shallow, the inflowing seawater easily resides, and a stable halocline readily forms because of the shape
of its basin, which suddenly deepens on the Pacific Ocean side.
Received: May 24, 1999 / Accepted: September 25, 1999 相似文献
74.
Meligy FY Shigemura K Behnsawy HM Fujisawa M Kawabata M Shirakawa T 《In vitro cellular & developmental biology. Animal》2012,48(4):203-215
The objective of the study is to evaluate efficiency of in vitro isolation and myogenic differentiation of mesenchymal stem
cells (MSCs) derived from adipose connective tissue (AD-MSCs), bone marrow (BM-MSCs), and skeletal muscle tissue (MC-MSCs).
MSCs were isolated from adipose connective tissue, bone marrow, and skeletal muscle tissue of two adult 6-wk-old rats. Cultured
MSCs were treated with 5-azacytidine (AZA) to induce myogenic differentiation. Isolated MSCs and differentiated cells were
evaluated by immunocytochemistry (ICC), fluorescence-activated cell sorting (FACS), PCR, and RT-PCR. AD-MSCs showed the highest
proliferation rate while BM-MSCs had the lowest one. In ICC, isolated MSCs had strong CD90- and CD44-positive expression and
negative expression of CD45, CD31, and CD34, while AZA-treated MSCs had strong positive desmin expression. In FACS analysis,
AD-MSCs had the highest percentage of CD90- and CD44-positive-expressing cells (99% and 96%) followed by BM-MSCs (97% and
94%) and MC-MSCs (92% and 91%).At 1 wk after incubation with AZA treatment, the peak of myogenin expression reached 93% in
differentiated MC-MSCs, 83.3% in BM-MSCs, and 77% in AD-MSCs. MSCs isolated from adipose connective tissue, bone marrow, and
skeletal muscle tissue have the same morphology and phenotype, but AD-MSCs were the most easily accessible and had the highest
rate of growth on cultivation and the highest percentage of stem cell marker expression. Moreover, although MC-MSCs showed
the highest rate of myogenic differentiation potential and expression of myoblast markers, AD-MSCs and BM-MSCs still can be
valuable alternatives. The differentiated myoblastic cells could be an available new choice for myoblastic auto-transplantation
in regeneration medicine. 相似文献
75.
Feces of wild chimpanzees in the Mahale Mountains, Tanzania, were inspected for intestinal parasites under a compound microscope.
Eggs or larvae ofOesophagostomum, Strongyloides, Trichuris, Prosthenorchis, andBertiella were found. Intestinal nematodes significantly increased in the mid-rainy season. This finding supports (or, at least, is
not in conflict with) the hypothesis thatAspilia leaves which are occasionally swallowed by chimpanzees may function as a vermicide, since ingestion of such leaves also increases
significantly in the mid-rainy season. 相似文献
76.
Horizontal distribution of the dinoflagellateCeratium hirundinella (O. F. Müller) Bergh in the Ishitegawa Reservoir, Ehime Prefecture, Japan, was investigated. Water quality was also surveyed. It was observed that the population ofC. hirundinella exponentially decreased in number from the head of the reservoir to the dam site. Further investigation proved thatC. hirundinella initiated growth at the head of the reservoir, and later gradually expanded downstream. It was found during the period of increase in water temperature that the cell density ofC. hirundinella at the uppermost station exponentially increased. 相似文献
77.
Soichiro Sakamoto Hiroshi Kawabata Taro Masuda Tatsuki Uchiyama Chisaki Mizumoto Katsuyuki Ohmori H. Phillip Koeffler Norimitsu Kadowaki Akifumi Takaori-Kondo 《PloS one》2015,10(10)
Ferritin is an iron-storage protein composed of different ratios of 24 light (L) and heavy (H) subunits. The serum level of ferritin is a clinical marker of the body’s iron level. Transferrin receptor (TFR)1 is the receptor not only for transferrin but also for H-ferritin, but how it binds two different ligands and the blood cell types that preferentially incorporate H-ferritin remain unknown. To address these questions, we investigated hematopoietic cell-specific ferritin uptake by flow cytometry. Alexa Fluor 488-labeled H-ferritin was preferentially incorporated by erythroid cells among various hematopoietic cell lines examined, and was almost exclusively incorporated by bone marrow erythroblasts among human primary hematopoietic cells of various lineages. H-ferritin uptake by erythroid cells was strongly inhibited by unlabeled H-ferritin but was only partially inhibited by a large excess of holo-transferrin. On the other hand, internalization of labeled holo-transferrin by these cells was not inhibited by H-ferritin. Chinese hamster ovary cells lacking functional endogenous TFR1 but expressing human TFR1 with a mutated RGD sequence, which is required for transferrin binding, efficiently incorporated H-ferritin, indicating that TFR1 has distinct binding sites for H-ferritin and holo-transferrin. H-ferritin uptake by these cells required a threshold level of cell surface TFR1 expression, whereas there was no threshold for holo-transferrin uptake. The requirement for a threshold level of TFR1 expression can explain why among primary human hematopoietic cells, only erythroblasts efficiently take up H-ferritin. 相似文献
78.
79.
Jim Kawabata Yukiharu Fukushi Satoshi Tahara Junya Mizutani 《Bioscience, biotechnology, and biochemistry》2013,77(3):713-717
Three novel sesquiterpene alcohols, shizuka-acoradienol (2), shizukafuranol (3) and shizukol-idol (4), were isolated from Chloranthus japonicus Sieb. (Japanese name: Hitori-shizuka, Chloranthaceae). Their structures were elucidated on the basis of their physicochemical properties and some chemical reactions. Furanodienone (5), scopoletin (6a) and isoscopoletin (6b) were also isolated from this plant. 相似文献
80.
A method was developed and applied for monitoring two types of fast-start locomotion (feeding and escape) of a cruiser fish, Japanese amberjacks Seriola quinqueradiata. A data logger, which incorporated a 3-axis gyroscope, a 3-axis accelerometer and a 3-axis magnetometer, was attached to the five fish. The escape, feeding and routine movements of the fish, which were triggered in tank experiments, were then recorded by the data logger and video cameras. The locomotor variables, calculated based on the high resolution measurements by the data logger (500 Hz), were investigated to accurately detect and classify the types of fast-track behaviour. The results show that fast-start locomotion can be detected with a high precision (0.97) and recall rate (0.96) from the routine movements. Two types of fast-start movements were classified with high accuracy (0.84). Accuracy was greater if the data were obtained from the data logger, which combined an accelerometer, a gyroscope and a magnetometer, than if only an accelerometer (0.80) or a gyroscope (0.66) was used. 相似文献