An Optimized Damage Identification Method of Beam Using Wavelet and Neural Network

An optimized damage identification method of beam combined wavelet with neural network is presented in an attempt to improve the calculation iterative speed and accuracy damage identification. The mathematical model is developed to identify the structure damage based on the theory of finite elements and rotation modal parameters. The model is integrated with BP neural network optimization approach which utilizes the Genetic algorithm optimization method. The structural rotation modal parameters are performed with the continuous wavelet transform through the Mexico hat wavelet. The location of structure damage is identified by the maximum of wavelet coefficients. Then, the multi-scale wavelet coefficients modulus maxima are used as the inputs of the BP neural network, and through training and updating the optimal weight and threshold value to obtain the ideal output which is used to describe the degree of structural damage. The obtained results demonstrate the effectiveness of the proposed approach in simultaneously improving the structural damage identification precision including the damage locating and severity.

Two-dimensional gel electrophoresis and surface-enhanced laser desorption ionization-time of flight-mass spectrometry for detection of protein expression profiles in the hippocampus following closed brain injury

Gene expression profile changes in brain regions following traumatic brain injury at the gene level cannot sufficiently elucidate gene expression time, expression amount, protein post-translational processing or modification. Therefore, it is necessary to quantitatively analyze the gene expression profile using proteomic techniques. In the present study, we established a rat model of closed brain injury using Marmarou＇s weight-drop device, and investigated hippocampal differential protein expression using two-dimensional gel electrophoresis and surface-enhanced laser desorption ionization-time of flight-mass spectrometry. A total of 364 protein peaks were detected on weak cation exchange-2 protein chips, including 37 differential protein peaks. 345 protein peaks were detected on immobilized metal affinity capture arrays-Cu, including 12 differential protein peaks Further examination of these differential proteins revealed that glucose-regulated protein and proteasome subunit alpha type 3 expression were significantly upregulated post-injury. These results indicate that brain injury can alter protein expression in the hippocampus, and that glucose-regulated protein and proteasome subunit alpha type 3 are closely associated with the occurrence and development of traumatic brain injury.

Distinct proteins in cortex of rats with closed traumatic brain injury detected by a WCX-2 protein chip

BACKGROUND： Mechanical injury can cause the changes of polygene expression spectrum in rat cerebral cortical nerve cells, and then result in the changes of intracellular protein expression. At present, dielectrophoresis is combined with mass spectrum technique to detect the expression of different proteins in rat cortex after brain injury, but the protein chip technique requires further investigation. OBJECTIVE： To analyze the differences of protein expression spectrum in rat cerebral cortex before and after closed traumatic brain injury using WCX-2 protein chip technique. DESIGN： A randomized controlled animal experiment. SETTING： Training Division of the Medical College of Chinese People＇s Armed Police Force. MATERIALS： Seventy-two male SD rats of clean degree, 350 - 450 g, were provided by the Experimental Animal Center, Academy of Military Medical Sciences of Chinese PLA. Urea, trifluoroacetic acid, CHAPS and Tris （Sigma, USA）; WCX-2 （Ciphergen, USA）. Ultra-high speed hypothermia centrifuger （Bechman, USA）; Rotary tissue microtome （Keuca, Germany）; Biochip processor and PBS II-C protein chip reader （Ciphergen, USA）. METHODS： The experiments were carried out in the Institute of Molecular Pathology, Central Laboratory, and Department of Pathology, Medical College of Chinese People＇s Armed Police Force from June 2005 to March 2006. ① Grouping and treatment： The experiments were completed in molecular pathological institute, central laboratory and pathological department. ② The rats were randomly divided into control group （n =12） and brain injury group （n =60）. Marmarou＇s weight-dropping models were duplicated at different time points in the brain injury group. In the control group, the rats were only treated by incising the skin of head top, without fixing the stainless steel hitting backup plate at the vault of skull, and obtain brain cortex for pathological and protein chip research, and they were killed after 24 hours. The rats in the brain injury group were killed at 4, 8, 12, 24 and 48 hours after model establishment. ③ Pathological observation： Longitudinal section was made on cerebral cortex, and sections of 5 μm were prepared, then stained with hematoxylin and eosin （HE）. ④Protein chip analysis： 100 mg cerebral cortex was collected from each rat, and the protein content in sample was detected with Bradford method, meanwhile, WCX-2 protein chip was used to analyze the protein spectrum. The data were automatically collected with Ciphergen proteinchip 3.0 software, and the results were analyzed using Biomarker Wizard software to compare the differences of protein spectrum in rat cortex between the groups. MAIN OUTCOME MEASURES： Results of the pathological observation of cerebral cortex and the protein spectrum analysis. RESULTS：①Pathological changes of cerebral cortex： In the control group, no necrosis and edema was observed. In the brain injury group, injures of different severity occurred at different time points; After 4 hours, focal or scattered red nerve cells could be observed, the size of some cells was increased, cytoplasm was lightly stained, and only nuclear fragments were seen; After 8 hours, the necrotic nerve cells were increased, and the number of nerve cells was reduced, astrocytes （neuronophagia） could be seen in partial cytoplasm; there was small vascular dilatation, and endothelial cell proliferation; interstitial edema, regional rarefaction lightly stained. After 12- 48 hours, the necrotic nerve cells were reduced, and astrocytes proliferated. ② Results of protein spectrum analysis： The WCX-2 experiment found that the expressions of 5 639, 3 212 and 7 536 u proteins in cerebral cortex changed after injury in the brain injury group. The peak intensity of 5 639 u protein in the brain injury group at 8 hours after injury was higher than that in the control group （P 〈 0.05）; The peak intensity of 3 212 u protein in the brain injury group at 48 hours after injury was higher than that in the control group （P 〈 0.05）; The peak intensity of 7 536 u protein at 24 hours after injury was higher than that in the control group （P 〈 0.05）. CONCLUSION： Brain injury can cause the changes of protein expression spectrum in cerebral cortex, it is suggested that brain injury can induce the expression of protein.

Differential protein expression in rat cortical astrocytes following fluid percussion injury Two-dimensional gel electrophoresis and mass-spectrum detection

BACKGROUND： The Glasgow Coma Scale, computer tomography, and nuclear magnetic resonance imaging have been frequently used to diagnose brain injury. However, these methods do not accurately and quantitatively evaluate injury degree. However, proteomics displays some advantages. To date, there are few proteomics studies based on primary astrocyte cultures from a fluid percussion injury model. OBJECTIVE： To detect differential protein expression in rat cerebral cortical astrocytes following fluid percussion injury using two-dimensional gel electrophoresis and mass spectrum and to determine specific biological markers of brain injury. DESIGN, TIME AND SETTING： Complete, randomized grouping and proteomics experiments were performed at the Molecular Pathological Laboratory, Central Laboratory and Tianjin Key Laboratory for Biomarkers of Occupational and Environmental Hazard of Medical College of Chinese People＇s Armed Police Force from October 2007 to May 2008. MATERIALS： Inverted phase-contrast microscope was purchased from Olympus, Japan. PROTEAN IEF Cell isoelectric focusing electrophoresis system and PROTEAN II Xi-Cell vertical electrophoresis system were purchased from Bio-Rad, USA. Autofiex MALDI-TOF mass spectrometer was purchased from Bruker, Germany. METHODS： A total of 90 culture dishes, fully coated with Sprague Dawley rat cortical astrocytes, were randomly divided into control （n = 30） and injury （n = 60） groups. Astrocytes in the injury group were subjected to fluid percussion and subdivided into 4-hour （n = 30） and 48-hour injury （n = 30） groups. MAIN OUTCOME MEASURES： Cell morphology was observed using inverted phase-contrast microscopy. Cell total protein was extracted from each group, followed by two-dimensional gel electrophoresis and silver staining, and the differential protein expression was analyzed using PDQuest 7.0 software. Protein peptide mass fingerprinting of differential protein spots was obtained by matrix assisted laser desorption/ionization-time of flight mass spectrometry. The National Center for Biotechnology Information （NCBI） protein database was retrieved by Mascot to primarily identify protein type, Finally, differential protein expression was detected by Western blot analysis. RESULTS： Following fluid percussion injury, astrocytes displayed obvious swelling and increased intercellular space, with some cell detachment; the number of dead cells was significantly greater than the control group （P 〈 0.05）. Expression intensity of 114 protein spots was significantly greater in the injury group compared with the control group （P〈 0.05）; 9 of the 114 protein spots were identified and peptJde matching scores of 8 spots were 〉 61 （P 〈 0.05）. Protein types were identified and included cellular retinol binding protein, brain fatty acid binding protein 7, $100 calcium binding protein All, 60S acidic ribosomal protein P2, calponin 3, breast carcinoma amplified sequence 2 homolog, eukaryotic translation initiation factor 1A, and hypothetical protein LOC685814. Western blot detection revealed brain fatty acid binding protein 7 expression in cortical astrocytes, which increased with injury time compared with the control group （P 〈 0.05）. CONCLUSION： Results from this study showed morphological and proteomic changes in cortical astrocytes following fluid percussion injury. Brain fatty acid binding protein 7 was expressed in astrocytes and possibly played an important role in injury repair. Mass-spectrum identified differentially expressed proteins that correlated with cell metabolism regulation, signal transduction, and translation initiation, and could serve as specific biological markers of brain injury.

Weak cation exchange 2 protein chip for detecting differentially expressed brainstem proteins in a rat model of closed traumatic brain injury

BACKGROUND： Studies have reported the combined use of two-dimensional gel electrophoresis and mass spectrometry to detect differentially expressed proteins in the rat brainstem following brain injury. However, the detected differential proteins often exhibit low sensitivity and high relative molecular weight. Although protein chip technology is thought to compensate for these inadequacies, no related studies or results have been reported. OBJECTIVE： To propose the application of weak cation exchange protein chips in combination with mass spectrometry for determining protein expression profiles and characteristics in the brainstem following closed brain injury. DESIGN, TIME AND SETTING： Randomized, controlled, animal experiments utilizing proteomics were performed from June 2007 to December 2008 in the Proteomics Laboratory, Medical College of Chinese People＇s Armed Police Force. MATERIALS： Weak cation exchange 2 protein chip, Ciphergen Proteinchip System （PBS-IIC）. METHODS： A total of 72 rats were randomly assigned to two groups： sham-surgery （n = 12） and injury （n = 60）. A closed traumatic brain injury model caused by falling object was replicated in the injury group, which was then subdivided into five subgroups according to different time points after injury： 4, 8, 12, 24, and 48 hours, with 12 rats in each subgroup. In the sham-surgery group, only the skin was removed and the stainless steel pad was fixed to the skull. MAIN OUTCOME MEASURES： The brain injury rats were sacrificed at 4, 8, 12, 24, and 48 hours after injury, respectively, and the control rats were sacrificed at 24 hours. Pathological changes in the brainstem were determined using hematoxylin-eosin staining, and differential protein expression in the brainstem was detected using a weak cation exchange 2 protein chip and protein chip reader. RESULTS： In the sham-surgery group, cells appeared normal. However, in the brain injury group, some brainstem neurons exhibited pyknosis, with reduced numbers of Nissl bodies in the cytoplasm swollen cell bodies and nuclei, irregular staining in the cytoplasm, and decreased numbers of neurons. Results from weak cation exchange 2 protein chip detection demonstrated that, compared with the sham-surgery group, the expression profiles of 2 proteins were altered in the brainstem of the injury group. At 12, 24, and 48 hours after injury, expression was increased （P 〈 0.01 ）. The mass charge ratio （M/Z） of 7 862 differentially expressed proteins was greater in the sham-surgery group compared with 12 and 24 hours after injury （P 〈 0.05）. CONCLUSION： The combined method of weak cation exchange 2 protein chip and mass spectrometry detected differential protein expression in the brainstem following closed brain injury in the rats, which suggested that closed brain injury induced altered protein expression profiles in the brainstem.

Empirical Analysis on Practice of Venture Investment in China

Organizational policy innovation in venture investment is an important measure to prompt making venture capital. This paper begins with introducing limited partnership, corporation and trust funds which are organizations suitable for venture investment, and then combines detailed case at home to analyze, reflect the develooment situation of venture investment in China.