Kinetic models of dichloroethylene biodegradation by two strains of aerobic bacteria / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>In this study, we examined the biodegradation of Dichloroethylene (DCE) by two strains of aerobic bacteria.</p><p><b>METHODS</b>Using batch experiments, we measured the biodegradation rates of DCE and the residual concentrations of DCE for each bacterial strain. The varying trends in biodegradation rates with different initial concentrations of DCE were fitted to kinetic models.</p><p><b>RESULTS</b>The biodegradation kinetics of DCE by the strain DT-X, which uses toluene as co-metabolic substrate, fitted the Monod model (corresponding parameters: v(max)=0.0075 h(-1), K(s)=2.12 mg/L). The biodegradation kinetics of DCE by the strain DT-M, which uses 1,1-Dichloroethylene as single substrate, fitted the Haldane model (parameters: v(max) =0.0046 h(-1), K(s)=4.25 mg/L, K(i)=8.47 mg/L).</p><p><b>CONCLUSION</b>The substrate removal rate constant of 1,1-Dichloroethylene of the co-metabolic strain DT-X was much higher than that of strain DT-M. The substrate removal rates obtained from both bacterial strains in this study were higher than those reported in similar studies.</p>

Effects of p,p'-DDE and beta-BHC on the apoptosis of Sertoli cells in vitro / 中华预防医学杂志

<p><b>OBJECTIVE</b>To explore the effects of p,p'-DDE and beta-BHC on the apoptosis of Sertoli cells in vitro via activation of Caspase.</p><p><b>METHODS</b>Sertoli cells were treated in vitro for 24 hours with a serial concentrations of p,p'-DDE (10, 30 and 50 micromol/L), beta-BHC (10, 30 and 50 micromol/L) and p,p'-DDE + beta-BHC (10, 30 and 50 micromol/L). The inhibitory group was first treated with 100 micromol/L Caspase-3 inhibitor Ac-DEVD-CHO treating for 2 hours before 50 micromol/L p, p'-DDE + 50 micromol/L beta-BHC 24 hours-treatment. The vitality of Sertoli cells was determined by MTT and the apoptosis rate was measured by AO/EB double fluorescence staining. The expressions of Caspase-3, Caspase-8 and Caspase-9 were determined by RT-PCR.</p><p><b>RESULTS</b>Average optical density (A) values were 0.498 +/- 0.039, 0.481 +/- 0.065, 0.397 +/- 0.032 and 0.286 +/- 0.049 in p,p'-DDE groups (10, 30, 50 and 70 micromol/L), and 0.518 +/- 0.103, 0.490 +/- 0.060, 0.454 +/- 0.054 and 0.302 +/- 0.030 in beta-BHC groups (10, 30, 50 and 70 micromol/L). In the mixture-treated groups (10, 30 and 50 micromol/L), the average A values were 0.483 +/- 0.048, 0.473 +/- 0.058 and 0.337 +/- 0.052. Compared with the solvent control group (0.527 +/- 0.022) , 50 micromol/L group of p, p'-DDE, beta-BHC or their mixture caused a significant decrease of Sertoli cell viability (t values were 4.599, 2.716, 6.537 respectively, P < 0.05). AO/EB double fluorescence staining analysis showed that apoptosis rates of Sertoli cells were significantly increased with all treated groups. The expressions of Caspase-3, Caspase-8 and Caspase-9 were upregulated as the concentrations of p,p'-DDE, beta-BHC and their mixture were increased.</p><p><b>CONCLUSION</b>p,p'-DDE, beta-BHC and their mixture could induce the apoptosis of Sertoli cells in vitro which was associated with activation of Caspase-3 mediated by cleavage of Caspase-8 and Caspase-9.</p>

Caracterizaçäo do polímero PVdF (polifluoreto de vinilideno) como sensor piroelétrico para utilizaçäo em termometria / PVdF polimer caracterization as pyroelectric sensor for utilization in thermometry

Este trabalho apresenta a caracterização de um sensor piroelétrico utilizando o polímero PVdF e visa estabelecer condições para seu uso como detetor térmico em aplicações na área médica onde são de interesse medidas de variações de temperatura da ordem de décimos de graus.

The objective of this work is to determine the basic characteristics of a pyroeletric sensor based on the polymer PV dF to establish the conditions for its use as a thermal detector in medical aplications for wich small temperature differences are of interest.