Effect of EMP on sex ratio of the offspring of male BALB/c mice / 中华放射医学与防护杂志

Objective To investigate the effects of EMP exposure to male BABL/c mice on the reproduction and its sex ratio.Methods Thirty-three male BALB/c mice were randomly divided into sham-exposed group,10 000 pulses/d exposed group,and 100 000 pulses/d exposed group with 50 Hz static magnetic field of 35 kV/m for 2 weeks consecutively,then the male mice were mated with unexposed females (1 male vs.2 female).Mated males were sacrificed to examine the exposure effects on sperm number and testis index after 7 days of mating.The sex ratio of embryos collected from unexposed mated females was investigated by PCR.Results The sex ratio of offspring was 0.298 (14/47) in the 10 000 pulses/d exposed group,significantly lower than 0.871 (27/31) in the sham-exposed group.No statistical changes were observed in the sex ratio of offspring,sperm number,the weights of testis and testis index after 100 000 pulses/d exposure.Conclusions The exposure of male mice to 35 kV/m EMP at 10 000 pulses/d for 2 weeks consecutively may change the sex ratio of mice's offspring.

Impression technique with a tissue-stop area for type four edentulous jaws / 华西口腔医学杂志

<p><b>OBJECTIVE</b>This study aims to develop a mandibular impression technique for type four edentulous jaws.</p><p><b>METHODS</b>Twenty patients with type four edentulous jaws were selected for this study. The mandibular impression for each patient was made using both a traditional impression technique and the impression technique with a tissue-stop area. After the cast was made for each impression, the temporary denture bases were constructed on each cast. When the patients wear temporary denture bases, they must appreciate the degree of comfortability provided by each denture base. Whether the soft tissues that had been pushed away was also recorded. For 10 of the randomly selected patients, a complete denture was made using the traditional impression technique; the remaining ten subjects were given complete dentures constructed by the impression technique with a tissue-stop area. The number of times a review for misfit was recorded. The tissue fitness of each denture was also recorded.</p><p><b>RESULTS</b>A paired t-test showed that the soft tissues that stacked on the residual ridge were more readily pushed away by the impression technique with a tissue-stop area than by the traditional impression technique. However, for all patients, the degree of comfortability did not vary when different techniques were used. The independent t-test results indicated that the differences between the fitness of dentures constructed using different impression techniques were not significant. The number of times a review for misfit conducted by the impression technique with a tissue-stop area was considerably lower than that for patients wearing traditionally dentures.</p><p><b>CONCLUSION</b>Using the impression technique with a tissue-stop area can more readily push away the soft tissues packed on the residual ridge and reduce the times of review for misfit compared with using the traditional technique. However, the degree of comfortability and fitness of denture are not improved.</p>