Shooting Distance Of Gunshot Wounds And Wound Age Estimation Experimental Study

Objective: Estimating firing distance is very important in inspection of gunshot. It is a key of rebuilding alibi. The judgment of firing distance depends on the amount and distribution of GSR around the entrance.The specifications of standard weapons and bullets are changeless, so the residue of the metal content and distribution should also unanimously after firing. According to GSR we can infer the firing distance and type of weapon. Ignition cap and the materials of gun are rapidly gasified and compressed in high temperature and high pressure, solidify soon after flying out gun barrel, then form the GSR. Now there are a deal of methods of detecting the GSR, but applications are limited for accuracy, sensitivity and observing the morphous of GSR. Scanning electron microscopy combining with X-ray spectroscopy detector can analyze composition and study the micromorphology at the same time. It increases the specificity of different types of GSR because of morphology and microelement quantitative analysis. So it makes of estimating bullets and firing distance. We study the distribution of GSR with different firing distance, establish score standard of GSR, and analyze the relation between distribution of GSR and firing distance, found homologous function. We hope to Provide a scientific basis for inspection of gunshot.Methods: Porkets was shot perpendicularity with"5.4"handgun or"7.9"submachinegun at the different firing distance (5cm, 10cm, 15cm, 20cm, 30cm, 40cm, 50cm, 60cm, 70cm, 80cm, 90cm, 120cm) in windless condition. pig skins from the entrance to the edge of 3cm away are made to samples, then to observe,count and analyze GSR with SEM and spectrum analysis. According to the scores of different distances and vision, using principal component analysis and multiple regression statistical theory, we analyze the corresponding relation of firing range and distribution of GSE with SAS statistical software, and establish a clear empirical formula.Results: Spectrum analysis of GSR of"5.4"handgun and"7.9"submachinegun all contain contain lead, antimony, barium. There are no differences in the two kinds of guns. Principal component regression analysis are using on the experimental data with SAS statistical software, and regression equations are obtained. From the difference between the actual value and the prediction value, it has a linear relationship betwwn firing distance and count of GSR particles.Conclusion: 1. To"5.4"handgun and"7.9"submachinegun, it can be used to estimate firing distance,and the regression equations are established that can be used to inspecte gunshot wounds. 2. Inspection of GSR with SEM/EDX can't be used to distinguish different guns that use the same bullets. OBJECTIVE: Though our government manage gun strictly, smuggling and self-made gun unceasing uninterrupt increase following opening to the outside world of our country. So the cases which refer to gun is increasing year by year. The study for gunshot injury knowledge is not a few at present, but the study to be specialized in the damage time for gunshot injury still no correlated report. In this experiment we observed the expression of protein and mRNA of MMP-1 and MMP-3 after gunshot injury by Western Blot and Northern Blot, in order to provide new evidence for judgement the time of gunshot injury.Method: The animals were devided into two groups:the negative group and the experimental group.The experimental group is for 0h,1h,3h,6h,12h,18h,24h,48h and 72h, the sample is three. The method for modelling of gunshot injury is using small antilinear pistol shot the experimental rats in a short distance and the control group is to draw the materials from the rats directly. Then getting the full-thickness skin at the location which spinula the wound of entry edge 0.5cm; Then undertaking quantitation detection for MMP-1 and MMP-3 by the method of Western Blot and Northern Blot.RESULTS: The results is identical in all the experimental groups by the two methods. MMP-1 and MMP-3 express at once after gunshot injury,then continue to advence and the tendency is to go up constantly.But there's no expression in the control group,the reason is the level of MMP-1 and MMP-3 in the normal dormancy tissue extremely low and difficult to detect,though they can be produced by many normal cell in vitro.The biological function of MMP-1 and MMP-3 is to express in period of time of tissue growth and reconstitution under the condition of physiology and pathology in vivo.All these show that MMP-1 and MMP-3 attend the reconstitution after gunshot injury.CONCLUSION: Gunshot injury induce the expression of MMP-1 and MMP-3, the regularity of its expression can be used to deduce the gunshot time.