ABSTRACT
The finite element method is a new method to study the mechanism of brain injury caused by blunt instruments. But it is not easy to be applied because of its technology barrier of time-consuming and strong professionalism. In this study, a rapid and quantitative evaluation method was investigated to analyze the craniocerebral injury induced by blunt sticks based on convolutional neural network and finite element method. The velocity curve of stick struck and the maximum principal strain of brain tissue (cerebrum, corpus callosum, cerebellum and brainstem) from the finite element simulation were used as the input and output parameters of the convolutional neural network The convolutional neural network was trained and optimized by using the 10-fold cross-validation method. The Mean Absolute Error (MAE), Mean Square Error (MSE), and Goodness of Fit ( R 2) of the finally selected convolutional neural network model for the prediction of the maximum principal strain of the cerebrum were 0.084, 0.014, and 0.92, respectively. The predicted results of the maximum principal strain of the corpus callosum were 0.062, 0.007, 0.90, respectively. The predicted results of the maximum principal strain of the cerebellum and brainstem were 0.075, 0.011, and 0.94, respectively. These results show that the research and development of the deep convolutional neural network can quickly and accurately assess the local brain injury caused by the sticks blow, and have important application value for understanding the quantitative evaluation and the brain injury caused by the sticks struck. At the same time, this technology improves the computational efficiency and can provide a basis reference for transforming the current acceleration-based brain injury research into a focus on local brain injury research.
Subject(s)
Humans , Brain , Brain Injuries , Computer Simulation , Finite Element Analysis , Neural Networks, ComputerABSTRACT
Background and purpose:Tumor microenvironment plays an important role in the introduction of foreign factors that mediate tumor acquired resistance. The antitumor effects of many chemotherapeutic agents depend on the level of oxygen pressure (pO2) in tumor microenvironment. This study aimed to evaluate electron paramagnetic reso-nance (EPR)-based monitoring on an oxygen-enriched tumor microenvironment to increase chemotherapeutic sensitivity. Methods:MCF-7 cells were used to establish human breast cancer in nude mice. EPR was used to directly measure pO2 levelin vivo. Tumor tissues were collected, and mitochondrial activity was assayed on the basis of the kinetics of enzyme-catalyzed reactions. A laser Doppler monitor was used to detect regional blood flow. Tumor apoptotic rate was analyzed by flow cytometry.Results:The tumor volume decreased more evidently in the chemotherapy group with oxy-gen-enriched environment than that in the conventional chemotherapy group after the treatment was administered (P<0.01). After chemotherapy was completed, the apoptotic rate of tumor cells was significantly higher in the chemotherapy group with oxygen-enriched environment than that in the conventional chemotherapy group (P<0.001). This study examined the mechanism ofpO2 changes in tumor microenvironment: This was related to the change of the balance between the oxygen consumption and the regional blood flow in the tumor tissues after chemotherapy.Conclusion:Based on the characteristics ofpO2 changes in the tumor microenvironment after chemotherapy was completed, the selection of chemotherapy mode forthe treatment inpO2 peak time window improves the sensitivity of chemotherapy, which provides a new idea for individual-ized chemotherapy in clinical applications.
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Objective To Study the expression of apo E protein changed in different wound age and position of the experimental traumatic brain injury(TBI) in rat. Methods The animal model of cerebral contusion was established by impact to the parietal lobe with a free fall weight,observed the changes of apo E in different wound age (0.5h、2h、6h、12h、24h、3d、7d、14d). The results were measured quantitatively with computer imaging analysis system. Results In cortex apo E-positive neurons definitely detected in 0.5h after brain injury, reaching the peak in 3d, then it shows the gradual decrease from 3d to 14d; In hippocampus apo E-positive neurons definitely detected in 0.5h after brain injury, reaching the peak in 3d in CA1 section and 24h in CA2～CA4. Then it shows the gradual decrease. We found the expression of apo E protein in CA1 section is stronger than others. Conclusion The location and intersity of the immunoreactivity of apo E protein changed at the different stages after TBI. These changes observed in the present study might be used for determination of injury time,early diagnosis and distinguish antemortem and postmortem brain injury in forensic medicine.
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Recent researches have showed that neural stem cells be isolated not only in the embryonic nervous system but also in adult nervous system. Neural stem cells have some capacity for self-renewal, migration and can differentiate into neurons, astrocyte and oligodendrocyte. This provides a basis in therapy of degenerative diseases and functional recovery of the central nervous system injury. Also helps in the study of determining the postmortem interval ( PMI) and postmortem injury. Distribution, biological characteristic, identification and the factors effecting the proliferation, differentiation and migration with reference to therapy of neural stem cells and applications in forensic pathology are reviewed.