[The influence of oil heat treatment on wood decay resistance by Fourier infrared spectrum analysis].

Wood preservative treatment can improve defects of plantation wood such as easy to corrupt and moth eaten. Among them heat-treatment is not only environmental and no pollution, also can improve the corrosion resistance and dimension stability of wood. In this test Poplar and Mongolian Seoteh Pine was treated by soybean oil as heat-conducting medium, and the heat treatment wood was studied for indoor decay resistance; wood chemical components before and after treatment, the effect of heat treatment on wood decay resistance performance and main mechanism of action were analysed by Fourier infrared spectrometric. Results showed that the mass loss rate of poplar fell from 19.37% to 5% and Mongolian Seoteh Pine's fell from 8.23% to 3.15%, so oil heat treatment can effectively improve the decay resistance. Infrared spectrum analysis shows that the heat treatment made wood's hydrophilic groups such as hydroxyl groups in largely reduced, absorbing capacity decreased and the moisture of wood rotting fungi necessary was reduced; during the heat treatment wood chemical components such as cellulose, hemicellu lose were degraded, and the nutrient source of wood rotting fungi growth necessary was reduced. Wood decay fungi can grow in the wood to discredit wood is because of that wood can provide better living conditions for wood decay fungi, such as nutrients, water, oxygen, and so on. The cellulose and hemicellulose in wood is the main nutrition source of wood decay fungi. So the oil heat-treatment can reduce the cellulose, hemicellulose nutrition source of wood decay fungi so as to improve the decay resistance of wood.

[The relationship of injury timing with the change of neuronal apoptosis and the expression of caspase-3 after brain contusion].

OBJECTIVE: To investigate and analyze the changes of neuronal-apoptosis and the expression of caspase-3 for finding out a new method of injury timing after brain contusion in human. METHODS: The tissue was stained by TUNEL for apoptosis and by immunohistochemistry for caspase-3. Image analysis technique was employed. RESULTS: The nerve cells stained positive by TUNEL and Caspase-3 immunohistochemistry were distributed in the penumbra and central area. Both these areas were in striking contrast with the distal area or those of control group. The positive staining was more prominente in penumbra area than in central area (P < 0.05). The changes of TUNEL staining and expression of Caspase-3 in penumbra area gradually increased with the survival period after injury; they were parallel to each other. There were linear relationships between the time of injury in 48 hours and the increase in the mean of integral optical density (IOD), the coefficient of correlation (r) being 0.93 and 0.69 for the two staining methods, and two linear regression formulae were induced, respectively. CONCLUSION: Observations on the increasing of neuronal apoptosis and Caspase-3 expression in relation with the survival period after injury could be utilized in the timing of brain contusion.

[Relationship between the injury time and DNA fragmentation and its quantity in rat brain].

OBJECTIVE: To observe the changes of DNA fragmentation and its quantity along with the time of injury in nerve cells after brain contusion. METHODS: The model of brain contusion caused by free drop hammer was established. TUNEL and Feulgen's DNA staining conjoined with image analysis technique were used for exploration. RESULTS: With the gradually rising of DNA fragmentation, DNA quantity was declining in the brain tissue after contusion. CONCLUSION: TUNEL and Feulgen's DNA staining conjoined with image analysis technique could be utilized in the timing of brain injury and provide a new approach for this issue.

[Retrospective analysis of autopsy on 49 cases of medical tangles in perinatal period].

Medical tangles caused by the death of women and infants in perinatal period are very normal in the forensic appraisal. The author collected and analyzed 49 cases of these tangles from many aspects, such as sex and age of the dead, hospital,information of autopsy, fault of medical action and so on,and discovered the normal causes of death, medical action's effects and the causes of tangle. It would be useful to the forensic appraisal, settlement and prevention of these medical tangles.