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991.
992.
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
993.
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
994.
Seiji Kawamoto Naoko Iemura Yuichi Inoue Yoshinori Katakura Sanetaka Shirahata 《Cytotechnology》2000,33(1-3):253-257
We have previously shown that 14-3-3 protein, amultifunctional adaptor molecule involved in many aspects ofsignal transduction pathways, is a target antigen for thecancer-associated human monoclonal antibody. Although recentevidences suggest a crucial role of 14-3-3 family members inthe control of cell growth and differentiation, their actualcontribution toward tumor development is still controversial. Inthis article, we examined the effect of enforced 14-3-3overexpression on cell growth of the human lung adenocarcinomacell line, A549. To address this issue, we obtained14-3-3 protein-inducible A549 sublines by transfection with14-3-3 expression vector under the control ofdexamethasone-inducible promoter. We found that 14-3-3 proteininduction in some of these sublines promoted their cell proliferation. Microscopic observation revealed that morphologyof these cells became aggressive multilayer condition,suggesting that malignant phenotypes are also acquired uponectopic induction of 14-3-3 protein. 相似文献
995.
996.
Sou Nobukawa Nobuhiko Wagatsuma Takashi Ikeda Chiaki Hasegawa Mitsuru Kikuchi Tetsuya Takahashi 《Cognitive neurodynamics》2022,16(4):871
Synchronization of neural activity, especially at the gamma band, contributes to perceptual functions. In several psychiatric disorders, deficits of perceptual functions are reflected in synchronization abnormalities. Plausible cause of this impairment is an alteration in the balance between excitation and inhibition (E/I balance); a disruption in the E/I balance leads to abnormal neural interactions reminiscent of pathological states. Moreover, the local lateral excitatory-excitatory synaptic connections in the cortex exhibit excitatory postsynaptic potentials (EPSPs) that follow a log-normal amplitude distribution. This long-tailed distribution is considered an important factor for the emergence of spatiotemporal neural activity. In this context, we hypothesized that manipulating the EPSP distribution under abnormal E/I balance conditions would provide insights into psychiatric disorders characterized by deficits in perceptual functions, potentially revealing the mechanisms underlying pathological neural behaviors. In this study, we evaluated the synchronization of neural activity with external periodic stimuli in spiking neural networks in cases of both E/I balance and imbalance with or without a long-tailed EPSP amplitude distribution. The results showed that external stimuli of a high frequency lead to a decrease in the degree of synchronization with an increasing ratio of excitatory to inhibitory neurons in the presence, but not in the absence, of high-amplitude EPSPs. This monotonic reduction can be interpreted as an autonomous, strong-EPSP-dependent spiking activity selectively interfering with the responses to external stimuli. This observation is consistent with pathological findings. Thus, our modeling approach has potential to improve the understanding of the steady-state response in both healthy and pathological states. 相似文献
997.
998.
Circulating factor with ouabain-like immunoreactivity in patients with primary aldosteronism 总被引:5,自引:0,他引:5
F Masugi T Ogihara T Hasegawa A Tomii M Nagano K Higashimori K Kumahara Y Terano 《Biochemical and biophysical research communications》1986,135(1):41-45
Circulating factor with ouabain-like immunoreactivity was studied in patients with primary aldosteronism. Anti-ouabain antibody was prepared from specific pathogen-free rabbits. In the plasma of patients with primary aldosteronism, the level of a factor with ouabain-like immunoreactivity was 2.59 +/- 1.39 pmol ouabain equivalent/ml plasma. This value was significantly (p less than 0.05) higher than that of age-matched normotensive subjects, 1.06 +/- 0.86 pmol ouabain equivalent/ml plasma. The plasma level of ouabain-like immunoreactivity correlated significantly (p less than 0.05) with blood pressure. These results indicate that the factor with ouabain-like immunoreactivity may play a pathophysiological role in the maintenance of the high blood pressure observed in patients with primary aldosteronism. 相似文献
999.
Colin C Demasi MA Degaki TL Bustos-Valenzuela JC Figueira RC Montor WR Cruz LO Lojudice FH Muras AG Pereira TM Winnischofer SM Hasegawa AP Carreira AC Verbisck NV Corrêa RG Garay-Malpartida HM Mares-Guia TR Corrêa-Giannella ML Granjeiro JM Sogayar MC 《Molecular biotechnology》2008,39(2):89-95
Social and economical development is closely associated with technological innovation and a well-developed biotechnological industry. In the last few years, Brazil’s scientific production has been steadily increasing; however, the number of patents is lagging behind, with technological and translational research requiring governmental incentive and reinforcement. The Cell and Molecular Therapy Center (NUCEL) was created to develop activities in the translational research field, addressing concrete problems found in biomedical and veterinary areas and actively searching for solutions by employing a genetic engineering approach to generate cell lines over-expressing recombinant proteins to be transferred to local biotech companies, aiming at furthering the development of a national competence for local production of biopharmaceuticals of widespread use and of life-saving importance. To this end, mammalian cell engineering technologies were used to generate cell lines over-expressing several different recombinant proteins of biomedical and biotechnological interest, namely, recombinant human Amylin/IAPP for diabetes treatment, human FVIII and FIX clotting factors for hemophilia, human and bovine FSH for fertility and reproduction, and human bone repair proteins (BMPs). Expression of some of these proteins is also being sought with the baculovirus/insect cell system (BEVS) which, in many cases, is able to deliver high-yield production of recombinant proteins with biological activity comparable to that of mammalian systems, but in a much more cost-effective manner. Transfer of some of these recombinant products to local Biotech companies has been pursued by taking advantage of the São Paulo State Foundation (FAPESP) and Federal Government (FINEP, CNPq) incentives for joint Research Development and Innovation partnership projects. 相似文献
1000.
Iwasaki A Yamada Y Kizaki N Ikenaka Y Hasegawa J 《Applied microbiology and biotechnology》2006,69(5):499-505
Arthrobacter sp. KNK168 shows (R)-enantioselective transaminase [(R)-transaminase] activity, which converts prochiral ketones into the corresponding chiral (R)-amines in the presence of an amino donor. The cultural conditions and reaction conditions for asymmetric synthesis of chiral
amines with this microorganism were examined. The transaminase was inducible, and its production was enhanced by the addition
of sec-butylamine and 3-amino-2,2-dimethylbutane to the culture medium. (R)-1-Phenylethylamine was a good amino donor for amination of 3,4-dimethoxyphenylacetone with Arthrobacter sp. KNK168. Under the optimum conditions, 126 mM (R)-3,4-dimethoxyamphetamine (DMA) [>99% enantiomeric excess (ee)] was synthesized from 154 mM 3,4-dimethoxyphenylacetone and
154 mM (R)-1-phenylethylamine through the whole cell reaction with an 82% conversion yield. (R)-Enantiomers of other amines, such as (R)-4-methoxyamphetamine, (R)-1-(3-hydroxyphenyl)ethylamine and (R)-1-(3-hydroxyphenyl)ethylamine, were also synthesized from the corresponding carbonyl compounds through asymmetric amination
with Arthrobacter sp. KNK168. 相似文献