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21.
Previous studies have found that exposure of a cyclic parthenogen, the water flea Daphnia magna (Cladocera, Crustacea), to juvenile hormones and their analogs results in the production of neonates of male sex at concentration-dependent rates. We conducted reproduction experiments in four different species (Moina macrocopa, M. micrura, Ceriodaphnia dubia and C. reticulata) of cladoceran to test for the first time whether the occurrence of this phenomenon after exposure of the parent to such hormones is a generalized phenomenon. In the presence of a juvenile hormone analog, fenoxycarb, all four species produced male neonates and showed reduced rates of reproduction. The estimated median effective concentration (EC50) for the production of male neonates varied with species, ranging from 0.60 x 10(3) to 9.3 x 10(3) ng/l. Although there was a wide range of sensitivity to fenoxycarb, the production of male neonates in all four species demonstrates that this phenomenon is a common response to juvenile hormone analogs and further suggests that these hormones are capable of initiating sexual reproduction in cladocerans, most of which exhibit cyclic parthenogenesis. 相似文献
22.
Naoko Takada-Oikawa Norihisa Katoh Toshio Oshida Sukeo Kawanabe Toshikazu Kaise 《Journal of Material Cycles and Waste Management》2000,2(2):138-142
A potting experiment was carried out to determine the effects of soil amendments containing polysaccharides and earthworms
on a land application system for the purification of animal waste water. The following soil amendments were used: purified
Konjak powder (KP, powder containing glucomannan made from the root system of devil's tongue, Amorphophalus rivieri Dur.), crystallized cellulose (CC), and a mixture of the two (MX). These soil amendments were added to the pots, and then
Chrysanthemum corondria were planted in the earthworm pots (A pots), the nonearthworm pots (B pots), and the control pots (C pots); the first two
plots received primary-treated animal waste water, and the other one received tap water. The following items were then measured:
pH, electrical conductivity, chemical oxygen demand (CODMn), total nitrogen (TN), total phosphorus, the volume of drained water from each pots, the height and dry matter weight of
plants, and the water permeability into the soil. The MX-A pots, i.e., the pots containing both soil amendments and earthworms,
gave good results, especially for water permeability, plant growth, the purification of CODMn, and TN. These results suggest that the presence of soil amendments and earthworms may enhance the improvement of water quality
in land application systems using vegetation.
Received: December 9, 1998 / Accepted: February 8, 2000 相似文献
23.
Tsuji M Vogel CF Koriyama C Akiba S Katoh T Kawamoto T Matsumura F 《Chemosphere》2012,87(11):1228-1234
Background
One of the suggested health outcomes of PCB exposure is childhood asthma.Objectives
This study was conducted to find health relevant biomarkers providing the molecular epidemiological evidence for the positive relationship between exposure to PCBs and childhood asthma.Methods
Blood samples from fifteen asthmatic children as well as an equal number of non-asthmatic children (average 2 year old) were collected, and were analyzed for PCBs and their select marker expression by using qRT-PCR.Results
Among biomarkers examined IL-8 expression was significantly correlated to serum levels of PCB #163 + 164 (P = 0.022), #170 (P = 0.046), #177 (P = 0.022), #178 (P = 0.022) and #180 + 193 (P = 0.046) in a dose-dependent manner, which was found only among asthmatic children. In contrast, COX-2 correlations to individual congener levels were recognized only among control subjects, not among asthmatic subjects.Conclusion
Serum concentrations of PCB#163 + 164, #170, #177, #178 and #180 + 193 correlate significantly with IL-8 mRNA expressions among asthmatic children. 相似文献24.
Inoue S Oshima Y Usuki H Hamaguchi M Hanamura Y Kai N Shimasaki Y Honjo T 《Chemosphere》2007,66(7):1353-1357
We investigated the effects of waterborne and maternal exposure to tributyltin (TBT) on veliger larvae of the Manila clam, Ruditapes philippinarum. In a waterborne exposure test, veliger larvae (D-larvae stage: 24h after fertilization) were exposed to TBT at measured concentrations of <0.01 (control), 0.055, 0.130, 0.340, and 0.600microg/l for 13d. The percentage of normal veliger larvae (the ratio of normal veliger larvae to all larvae) decreased significantly in all TBT treatment groups compared with that in the control group. In a maternal exposure test, 100 clams were exposed to TBT at measured concentrations of <0.01 (control), 0.061, and 0.310microg/l at 20-22 degrees C for 3 weeks, and the percentage of normal veliger larvae assessed for 13d. No maternal effects on veliger larvae from TBT were observed in TBT treatment groups as compared with the control group. These results demonstrate that waterborne TBT affects Manila clam veliger larvae, and indicates that TBT may have reduced Manila clam populations by preventing the development and survival of veliger larvae. 相似文献
25.
Nilawati Dewi Matsuura Norihisa Honda Ryo Hara-Yamamura Hiroe Sintawardani Neni Yamamoto-Ikemoto Ryoko 《Journal of Material Cycles and Waste Management》2021,23(2):537-547
Journal of Material Cycles and Waste Management - Wastewater generated during acid coagulation in tofu processing has high organic concentrations and low pH. Several small industries in Indonesia... 相似文献
26.
Dynamic response of the scenic beauty value of different forests to various thinning intensities in central eastern China 总被引:1,自引:0,他引:1
Songqiu Deng Na Yin Qingwei Guan Masato Katoh 《Environmental monitoring and assessment》2014,186(11):7413-7429
Forest management has a significant influence on the preferences of people for forest landscapes. This study sought to evaluate the dynamic effects of thinning intensities on the landscape value of forests over time. Five typical stands in Wuxiangsi National Forest Park in Nanjing, China, were subjected to a thinning experiment designed with four intensities: unthinned, light thinning, moderate thinning, and heavy thinning. People’s preferences for landscape photographs taken in plots under various thinning intensities were assessed through scenic beauty estimation (SBE) at 2 and 5 years after thinning. The differences in scenic beauty value between different thinning intensities were then analyzed with a paired samples t test for the two periods. The results indicated that the landscape value of all of the thinned plots significantly exceeded that of the unthinned plots 2 years after thinning (p?0.01) and that the heavily thinned plots were most appreciated, showing an average improvement of 9.71 % compared with the control plots. Additionally, the heavily thinned plots were judged to be more beautiful than the lightly thinned and moderately thinned plots, whereas there was no significant difference between moderate thinning and light thinning. At 5 years after thinning, however, the moderately thinned plots received the highest preference scores among the four intensities, displaying an average improvement of 11.32 % compared with the unthinned plots. A multiple linear regression (MLR) model indicated that landscape value improved with increases in the average diameter at breast height (DBH) and with the improvement of environmental cleanliness in the stand, whereas the value decreased with an increasing stem density, species diversity, litter coverage, and canopy density. In addition, we found that the performance of a neural network model based on a multilayer perception (MLP) algorithm for predicting scenic beauty was slightly better than that of the MLR model. The findings of our study suggest that moderate to heavy thinning should be recommended to manage forests for the improvement of forest landscape value. 相似文献
27.
The efficiency of electron injection (Φ(inj)) in dye-sensitized nanocrystalline films was studied through transient absorption (TA) and time-resolved microwave conductivity (TRMC) measurements. Here, I show the absolute value of Φ(inj) for several dye-sensitized nanocrystalline films and discuss the relationship between Φ(inj) and the free energy change (-ΔG (inj)) for the injection process. Some systems exhibited lower Φ(inj) values even when -ΔG (inj) was sufficiently large to promote electron injection. Recent experimental findings are used to propose possible explanations for this phenomenon. Quantitative evaluation of Φ(inj) using TA and TRMC will give us new insights for developing high-performance solar cell devices. 相似文献
28.
Paying attention to the ignition potentiality of static electricity, the relation between the discharge characteristics and the ignition of a dust cloud and the gas produced was studied, applying an electrical power supply of which the electrical circuit is adjustable. The effect of ignition characteristics on dust and gas explosions was investigated. The results of the study indicate that the probability of an explosion is influenced by the minimum ignition energy, spark duration time, feeding rate of ignition energy, circuit capacitance, ignition voltage, etc. 相似文献
29.
The development of gill chloride cells was examined in premetamorphic larvae (leptocephali) and juveniles (glass eels) of the Japanese eel, Anguilla japonica. Branchial chloride cells were detected by immunocytochemistry using an antiserum specific for Na+,K+-ATPase. The specificity and availability of the antiserum for the detection of Japanese eel chloride cells were confirmed by Western blot analysis. The chloride cells first appeared on the developing gill filaments in a mid larval stage of leptocephalus (32.2 mm). Both immunoreactivity and the number of chloride cells gradually increased as the fish grew to a late stage of leptocephalus over 54 mm. In glass eels just after metamorphosis, gill lamellae developed from the gill filaments, and a rich population of chloride cells was observed in the gill filaments. In glass eels collected at a coastal area, chloride cells were extensively distributed in the gill filaments. The chloride cell size decreased progressively in glass eels transferred from seawater (SW) to freshwater (FW), whereas there was no difference in cell number. In contrast, some Na+,K+-ATPase immunoreaction distinct from typical chloride cells was observed in the gill lamellae throughout FW-transferred fish, but disappeared in control fish maintained in SW for 14 days. These findings indicate that the gill and gill chloride cells developed slowly during the extremely long larval stage, followed by rapid differentiation during a short period of metamorphosis. The excellent euryhalinity of glass eels may be due to the presence of the filament chloride cells and lamellar Na+,K+-ATPase-immunoreaction, presumably being responsible for SW and FW adaptation, respectively. 相似文献
30.
Life history of the golden ring cowry Cypraea annulus (Mollusca: gastropoda) on Okinawa Island,Japan
M. Katoh 《Marine Biology》1989,101(2):227-234
Two mark-recapture studies, regular population censuses, field observations, and laboratory culture were used to study the life history of the tropical marine gastropod Cypraea annulus Linnaeus, 1758 from Cape Maeda, Okinawa Island, from April 1984 to March 1986. In the field, the average rate of increase in shell length of marked juvenile snails was 1.0±0.3 mm wk-1 (N=13), with a maximum of 1.5 mm wk-1 (initial shell length 10.6 to 17.2 mm). In the laboratory, the maximum growth rate of juveniles was 3.0 mm wk-1 with food ad libitum. Snails with primordial teeth on the shells grew at a rate of 0.1 to 0.5 mm wk-1 for about 2 wk. The adults continued to grow at a similar rate for an additional 3 to 6 wk, and ceased detectable growth when some females started spawning egg masses. In the littoral zone on Okinawa Island, snails reproduced throughout the year. Egg masses brooded by three females (shell length 17.4 to 21.3 mm) in the field contained 90 000 to 133 000 ova. In the laboratory, brooding periods of three females lasted 6,8, and 9 d. The estimated average frequency of spawning was 5 egg masses female-1 yr-1. The mean shell length of adult females (20.3 mm) was significantly larger than that of adult males (19.6 mm). The life-history strategy of C. annulus is characterized by rapid growth, high fecundity, and repeated spawning throughout the year. 相似文献