Journal of Zhejiang University. Science最新文献

Modeling of solute transport is a key issue in the area of soil physics and hydrogeology. The most common approach (the convection-dispersion equation) considers an average convection flow rate and Fickian-like dispersion. Here, we propose a solute transport model in porous media of continuously expanding scale, according to the combinatorics principle. The model supposed actual porous media as a combinative body of many basic segments. First, we studied the solute transport process in each basic segment body, and then deduced the distribution of pore velocity in each basic segment body by difference approximation, finally assembled the solute transport process of each basic segment body into one of the combinative body. The simulation result coincided with the solute transport process observed in test. The model provides useful insight into the solute transport process of the non-Fickian dispersion in continuously expanding scale.

Objective: To investigate the influence of lead exposure on the immune function of lymphocytes and erythrocytes in preschool children.

Materials and methods: A group of 217 children three to six years of age from a rural area were given a thorough physical examination and the concentration of lead in blood samples taken from each subject was determined. The indices of lymphocyte immunity (CD+3CD+4, CD+3CD+8, CD+4CD+8, CD-3CD+19) and erythrocyte immunity (RBC-C3b, RBC-IC, RFER, RFIR, CD35 and its average fluorescence intensity) of 40 children with blood lead levels above 0.483 micromol/L were measured and compared with a control group.

Results: The blood lead levels of the 217 children ranged from 0.11 micromol/L to 2.11 micromol/L. The CD+3CD+4 and CD+4CD+8 cells were lower (P<0.01) and the CD+3CD+8 cells were higher in the lead-poisoned subjects than those in the control group (P<0.05). CD+3 and CD-3CD+19 did not show significant differences. Although the RBC-C3b rosette forming rate was lower and the RBC-IC rosette forming rate was higher in the lead-poisoned group, this difference could not be shown to be statistically significant (P>0.05). RFIR was found to be lower in the lead-poisoned group (P<0.01). Compared with the control group, the positive rate of CD35 was not found to be significantly different in a group of 25 lead-poisoned children (P>0.05), while the average fluorescence intensity was lower in the lead-poisoned group (P<0.05).

Conclusion: Lead exposure can result in impaired immune function of T lymphocytes and erythrocytes in preschool children.

Objective: To construct a PC12 cell strain with neuronal differentiation, and observe the apoptosis and proliferation activity effects induced these cells by Amyloid beta-Protein (Abeta-43).

Methods: 1) PC12 cells in logarithmic growth phase were subcultured for 24 h. After the culture fluid was changed, the cells were treated with Rat-beta-NGF and cultured for 9 days. 2) Neuronal differentiation of PC12 cells in logarithmic growth phase were divided into four groups: control group (0), experimental group (1), experimental group (2) and experimental group (3). The concentrations of Abeta in the four groups were 0 micromol/L, 1.25 micromol/L, 2.5 micromol/L and 5 micromol/L, respectively. The cells were harvested at 24, 48 and 72 h later and stained with AnnexinV-FITC/PI after centrifugation and washing. Then flow cytometry was conducted to examine the apoptosis percentage. 3) NGF-induced PC12 cells were selected and Abeta with different concentrations was added. The final concentrations of Abeta were 0 micromol/L, 1.25 micromol/L, 2.5 micromol/L and 5 micromol/L, respectively. After the cells were incubated in an atmosphere of 5% CO2 at 37 degrees C in an incubator for 72 h, the OD values were examined.

Results: 1) Neuronal differentiated PC12 cell lines were successfully established. 2) Flow cytometric examination indicated that Abeta (1.25, 2.5, and 5.0 micromol/L) could effectively induce apoptosis of neuronal-differentiated cells at the 24 h, 48 h and 72 h time points. 3) Abeta (0-5.00 micromol/L) had no obvious effect on proliferation or restraining of the neuronal differentiation of the PC12 cells after a 72 h interacting process.

Conclusion: This investigation revealed successful neuronal differentiation of the PC12 cell strain. The induction of apoptosis of the neurocytes by various concentrations of Abeta was observed and the influence of Abeta on induced proliferation of PC12 cells by Rat-beta-NGF was revealed. This study may provide basis for future research on the molecular cure of AD and interdiction of AD evolution.