Biomedical subjects

Fayun Li

Publications and source records attributed to Fayun Li.

6 recordsLinked to original sources

PubMed2006

Hydroxyl radical generation and oxidative stress in Carassius auratus liver as affected by 2,4,6-trichlorophenol.

With Carassius auratus, one of the main economic fish species in Eastern China as test material, this paper studied the hydroxyl radical generation and oxidative stress in its liver under the effect of 2,4,6-trichlorophenol (2,4,6-TCP). Different doses of 2,4,6-TCP were injected intraperitoneally into the fishes, and the Electron paramagnetic resonance (EPR) spectra of hepatic free radicals, activities of superoxide dismutase (SOD), catalase (CAT) and glutathione-s-transferase (GST), levels of reduced glutathione (GSH) and oxidized glutathione (GSSG), and malondialdehyde (MDA) contents were determined 24h after injection. The results showed that under the effects of 2,4,6-TCP, the generation of free radical that was considered to be hydroxyl radical increased significantly, the activities of antioxidant enzymes decreased, with CAT most strongly affected and followed by SOD and GST, the GSH level decreased significantly while GSSG level had little difference, resulting in a decreased GSH/GSSG ratio, and the MDA content increased significantly. All the test parameters showed that C. auratus was subjected to oxidative stress and damage when exposed to 2,4,6-TCP.

Animals↗

PubMed2005

[Research progress on environmental carrying capacity].

To study the theories and quantification methods of environmental carrying capacity is of significance in reality for directing human beings economic behaviors and harmonizing the relationships between social development and environment. In this paper, the definition of environmental carrying capacity was introduced from the aspects of "capacity", "threshold" and "capability", with the main characteristics of objective and subjective, regional and temporal, and dynamic and adjustable, and its research progress was reviewed. On the basis of these, the quantification methods of environmental carrying capacity, including exponential assessment, carrying rate assessment, system dynamics, and multi-objective optimization, were analyzed, and the research perspectives of environmental carrying capacity were discussed.

Conservation of Natural Resources↗

PubMed2005

[Phosphate adsorption and desorption characteristics of several fly ashes].

Through adsorption-desorption experiment and incubation test, this paper studied the phosphate adsorption and desorption characteristics of several fly ashes. The test fly ashes contained 0.545 - 4.540 g x kg(-1) of total P and 19.55 - 163.0 mg x kg(-1) of available P, which were significantly higher than those in soils. The P adsorption capacity of fly ashes increased with increasing added P, while their P adsorption rate was in adverse. Fly ashes had a higher P adsorption rate but a lower P desorption rate than soils, mainly because fly ashes had more P adsorption sites and stronger bound energy. In this study, Langmuir, Freundlich, and Temkin equations were fit to the measured data, and the MBC value in Langmuir equation, a value in Freundlich equation, and k2 value in Temkin equation could be used as a comprehensive index to characterize the potential phosphate adsorptivity of fly ashes. The larger these values were, the stronger the P adsorptivity was. The MBC, a and k2 value of 5 fly ashes collected from different locations was in order of Xiangtan power factory (5 167.7, 4 056.2 and 831.5) > Yueyang paper factory (1 650.7, 2803.4 and 711.9) >Huaneng power factory (303.0, 1677.6 and 368.7) > Zhuzhou power factory (34.7,413.48 and 213.8) > Dongting nitrogen fertilizer factory (34.7, 413.48 and 213.8). The P fixation by fly ashes generally increased with their increasing water content, and their phosphate adsorption was mainly specific adsorption and chemical precipitation, suggesting that the P fixation and the water content of fly ashes should be considered when fly ash was used as soil amendment or as compound fertilizer filling substance.

Adsorption↗

PubMed2003

[Seasonal variation of fixed ammonium content of paddy soils in Hunan Province and its bioavailability].

Three paddy soils with higher content of fixed ammonium in Hunan Province were used as test soils in pot experiment to study the seasonal variation of their fixed ammonium content and its bioavailability during rice growth period. The results showed that the fixed ammonium content in the paddy soils changed constantly during rice growth. Applying N fertilizer and organic manure increased the fixed ammonium content, which was decreased through the N uptake by rice plants. The recently fixed ammonium was almost fully available to rice, while the native fixed ammonium was partly available. The release of fixed ammonium during rice growth was newly alluvial sandy soil > purple clayey soil > alluvial sandy soil, and was greater a early growth stage than at later growth stage.

Biological Availability↗

PubMed2002

[Distribution characteristics and chemical pattern of cadmium in grasses planted in the cadmium contaminated soil].

In this paper, the distribution and chemical pattern of Cd in the grasses planted in Cd contaminated soil in western suburb of Shenyang were analyzed. The results showed that Cd was mainly distributed in the grass roots, and characteristics of Cd distribution in various grasses were different. Some grasses had resisting ability against Cd, some had strong capability of bio-accumulation for Cd. Results of different grasses extracted by different solvents showed that acid-soluble Cd in grasses was about 63.3% of total, and water-soluble and organic Cd were little, accounting for 0.7% and 0.4% of total respectively. Acid-soluble Cd was more active than the others during the transformation in the soil-plant system, while water-soluble Cd had certain regularity with the change of time and temperature, and organic Cd became more active with the increase of solvent polarity.

Cadmium↗

PubMed2002

[Fixed ammonium content of chief paddy soil types in Hunan Province and its influencing factors].

By the method of Silva and Bremner, the fixed ammonium content of chief paddy soil types in Hunan Province and its influencing factors were studied. The results showed that the content of fixed ammonium in plough layer ranged from 141 mg.kg-1 to 353 mg.kg-1, averaged 272 +/- 67 mg.kg-1, and accounted for 11.2% of total soil N. The content of fixed ammonium was in order of alluvial sandy soil > purple clayey soil > newly alluvial sandy soil > yellow clayey soil > reddish yellow clayey soil. There were four distribution models of fixed ammonium in the soil profiles: 1) fixed ammonium content increased with the increase of depth in the profiles; 2) fixed ammonium content decreased with the increase of depth; 3) there was no distinct change; and 4) abrupt increase or decrease was found in the profiles. The percentage of fixed ammonium to total N in soils always increased with the increase of depth. The fixation of NH4+ by soil was the strongest under 30 degrees C. Long-term submergence benefited to the fixation of NH4+ in newly alluvial sandy soil, purple clayey soil, and alluvial sandy soil, while the alternation of drying and wetting contributed to the fixation of NH4+ in yellow clayey soil best. The content of fixed ammonium in tested soil was correlated with the content of clay < 0.01 mm at the significant level, and not correlated with the content of clay < 0.001 mm, total N, organic N, and matter.

Oryza↗