Biomedical subjects

Jianjun Shi

Publications and source records attributed to Jianjun Shi.

7 recordsLinked to original sources

PubMed2006

Distribution and migration of 95Zr in a tea plant/soil system.

(95)Zr is a primary radionuclide in the radioactive liquid efflux from a pressurized water reactor and one of the main radionuclides released after nuclear accidents. The fission yield of (95)Zr is as high as 6.2%, however, its environmental behavior has not been well documented. An experiment was conducted to evaluate the accumulation and distribution of (95)Zr in a tea plant/soil system. (95)Zr was accumulated primarily in the trunk of tea plants after being taken up from the soil. The radioactivity concentration of (95)Zr in the trunk increased slowly with time, then it reached a dynamic equilibrium 14 days after application. The radioactivity concentration of (95)Zr in the other parts of the tea plant was very low; only slighter greater than the detection limit. The results indicated that (95)Zr was not readily translocated in the tea plant. About 98.9% of applied (95)Zr was found to concentrate in the upper 5 cm layer after being sprayed onto the soil surface. The results indicated that (95)Zr could not readily move downwards with percolating water due to strong adsorption to surface soil.

Environmental Monitoring↗

PubMed2006

Rabbits generated from fibroblasts through nuclear transfer.

Somatic cell nuclear transfer offers new opportunities for genetic engineering and genome preservation in mammalian animal species. We show that, in addition to cumulus cells, cultured adult rabbit fibroblasts are also capable of supporting full-term development after nuclear transfer. Nuclear transfer embryos constructed using serum-starved fibroblasts showed a significantly higher developmental rate than non-starved fibroblasts through preimplantation stages. A total of 467 nuclear transfer embryos were transferred into the oviducts of pseudo pregnant mothers. Eight of the 20 surrogate rabbits carried the pregnancy to term and five of them gave birth naturally to a total of nine rabbits. However, all of the offspring died before postnatal day 10. A Caesarean section was performed on three surrogates, giving birth to a total of five rabbits, three of them survived and grew into healthy adults. DNA analyses confirmed that these rabbits were genetically identical to the donor male rabbit. The present study demonstrates that rabbits can be cloned from adult fibroblasts after culture.

Animals↗

PubMed2003

[Behavior of HTO in simulated rice-water-soil ecosystem].

The behavior of transportation, accumulation and disappearance of HTO (tritium water) in a simulated rice-water-soil ecosystem was studied by using isotope-tracer techniques for simulated pollutants, and the fitting equation was confirmed by application of the open three-compartment system model and nonlinear regression method. The results showed that HTO in water was not only transferred to other compartments in the ecosystem, but also vaporized into atmosphere rapidly. Both free water tritium and bound tritium were found in the rice, and tritium of hygroscopic and crystalline water was consisted in the soil. The specific activity of free water tritium (or tritium of hygroscopic water) was stronger than that of bound tritium (or tritium of crystalline water). The specific activity of total tritium reduced after reaching the maximum in the rice and soil, and the bound tritium increased slowly. The specific activity of total tritium in stem was the strongest in the rice, and reached equipoise each other in the later stage gradually. The regression equations of accumulation and disappearance for the specific activity of total tritium in the water, soil and rice were given by analyzing the obtained data with exponential regression method. The analysis results of variance showed that each regression equation could describe the behavior of accumulation and disappearance of HTO in the rice-water-soil ecosystems preferably.

Ecosystem↗

PubMed2003

[Dynamics of 95Zr in simulated marine water-sediment-organisms system].

To provide scientific evidence to evaluate the behavior of 95Zr in ocean ecosystem, the dynamic model of the transference, accumulation and disappearance of 95Zr among the simulated marine water, sediment and organisms was investigated using Nassarius semiplicatus and Boleophthalums pectinirostris as experimental stuffs. The result showed that 95Zr(Bq.g-1 or Bq.ml-1) in the marine water was decreased more than 90% in the first 4 h, and then descended gradually. 95Zr in sediment was increased in the peak in 48 h and then declined. The radioactivity percent of 95Zr in the shell and muslce of Nassarius semiplicatus was 68.7% and 31.30% respectively, while the radioactivity percent was 22.80%, 12.64%, 34.82%, 10.31%, 4.48%, 11.55% and 3.71%, respectively in the fill, fin, viscera, skull, skin, vertebra and muscle of Boleophthalmus pectinirostris. Nassarius semiplicatus had a greater concentrating capability of 95Zr than Boleophthalmus pectinirostris. The order of the 95Zr concentration was found to be sediment > Nassarius semiplicatus > water > Boleophthalmus pectinirostris. A dynamic model of closed four-compartment was constructed with exponent function.

Animals↗

PubMed2002

Dynamics of 95Zr in the rice/water/soil system.

In order to get a better understanding of the environmental behavior of 95Zr and to generate fundamental data for evaluation of its ecological risk, an experiment was conducted to study 95Zr dynamics in a simulated rice/water/soil system. The results showed that the concentration of 95Zr in surface water decreased rapidly with time due to precipitation, adsorption to soil and uptake by rice, and most of 95Zr in soil was found concentrated in the surface layer (0-8 cm from surface). The 95Zr could not readily move downwards with percolating water and remained in surface soil. The 95Zr taken up from surface water and surface soil mainly concentrated in roots and lower parts of stem. The concentration of 95Zr in upper part of stem and leaves were relatively lower, which were only slightly greater than the detection limit. The 95Zr concentration in tassel was near the detection limit. The dynamics of 95Zr concentrations in rice, water and soil can be described with exponential function.

Environmental Monitoring↗

PubMed2002

[Dynamics of accumulation and disappearance of Zirconium-95 in the maize/soil and soybean/soil ecosystem].

The dynamics of accumulation and disappearance of 95Zr in two kinds crop-soil ecosystem was studied by using isotope-tracer techniques for simulated pollutants, and the fitting equation was confirmed by application of the closed tow-compartment model and nonlinear regression method. The results showed: 1. The Zirconium-95 absorbed from soil main retention in root of the maize and soybean, and the specific activity of 95Zr in root increased with time slowly, then tended dynamics balance gradually after a period of time. The specific activity of rest parts was lower, and biggish parts were background activity level, which indicated that the 95Zr absorbed by roots was difficult of transference and transportation in the maize and soybean. 2. The 95Zr in soil main retention in surface layer soil(0-8 cm), and the rate of it's activity and total activity > 97.5%, which indicated that the 95Zr absorbed by surface soil could not readily move downwards with percolating water. 3. The regression equation of accumulation and disappearance of 95Zr in the maize and soybean were Cm(t) = 3.2067(1 - e-0.1582t) and Cb(t) = 3.0925(1- e -0.1363t) by analyzing the experiment data with exponential regression method. The results of squared deviations analyzing indicated that each regression equation could describe the dynamics of accumulation and disappearance of 95Zr in the maize-soil and soybean-soil ecosystems preferably.

Ecosystem↗

PubMed2002

[Effect of covering with new soil on reducing the accumulation of radio-strontium in plant].

Effects of covering with new soil on reducing the accumulation of 89Sr by soybean and Chinese cabbage (especially in the edible part of crop) were studied on simulated pollutants by using the isotope-tracer techniques. The results showed that the absorption and accumulation of 89Sr in the soybean and Chinese cabbage could be decreased significantly by covering soil polluted 89Sr with new soil. The specific activity of 89Sr in bean hull, bean straw, bean root and Chinese cabbage were reduced by 82.8%, 56.4%, 38.7%, 66.5% and 68.8% respectively when the depth of covering with new soil reached 9 cm. The specific activity of absorption and accumulation 89Sr in the crop decreased with depth of the new soil profile. The specific activity of 89Sr in the crop follows a negative linear relation with depth of the new soil profile by analyzing the experiment data with linear regression method.

Plants↗