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Our previous studies showed that the early use of calpain inhibitors reduces calpain activity in multiple brain regions, and that postnatal treatment with calpeptin may lead to cerebellar motor dysfunction. However, it remains unclear whether postnatal calpeptin application affects hippocampus-related behaviors. In this study, Sprague-Dawley rats were purchased from the Animal Center of Anhui Medical University of China. For the experiments in the adult stage, rats were intraperitoneally injected with calpeptin, 2 mg/kg, once a day, on postnatal days 7–14. Then on postnatal day 60, the Morris water maze test was used to evaluate spatial learning and memory abilities. The open field test was carried out to assess anxiety-like activities. Phalloidin staining was performed to observe synaptic morphology in the hippocampus. Immunohistochemistry was used to count the number of NeuN-positive cells in the hippocampal CA1 region. DiI was applied to label dendritic spines. Calpeptin administration impaired spatial memory, caused anxiety-like behavior in adulthood, reduced the number and area of apical dendritic spines, and decreased actin polymerization in the hippocampus, but did not affect the number of NeuN-positive cells in the hippocampal CA1 region. For the neonatal experiments, neonatal rats were intraperitoneally injected with calpeptin, 2 mg/kg, on postnatal days 7 and 8. Western blot assay was performed to analyze the protein levels of Akt, Erk, p-Akt, p-Erk1/2, Erk1/2, SCOP, PTEN, mTOR, p-mTOR, CREB and p-CREB in the hippocampus. SCOP expression was increased, and the phosphorylation levels of Akt, mTOR and CREB were reduced in the hippocampus. These findings show that calpeptin administration after birth affects synaptic development in neonatal rats by inhibiting the Akt/mTOR signaling pathway, thereby perturbing hippocampal function. Therefore, calpeptin administration after birth is a risk factor for neurodevelopmental defects.

Low-loss slab waveguides with air as overcladding based on a high glass transition temperature ([T.sub.g]) polycarbonate were fabricated through spin-coating. Optical absorption and thermo-optic coefficient were investigated by spectrum analysis and prism coupler, respectively. Prism-coupling and charge-coupled device (CCD) camera imaging method were exploited together to evaluate the overall propagation loss of slab waveguides. The measured results of prism coupler were 0.282 dB/cm at 1310 nm and 0.197 dB/cm at 632.8 nm, whereas 0.07 dB/cm at 632.8 nm using CCD camera imaging method. Based on the same material, straight ridge waveguides and multimode interference couplers were fabricated through photolithograph and reactive ion etching, revealing smooth sides and excellent definition. POLYM. ENG. SCI., 49:2015-2019, 2009. [C]2009 Society of Plastics Engineers, INTRODUCTION Polymer materials have great applications in the field of planar lightwave circuit in the past decade because of its merits of ease in fabrication and energy-saving property (e.g., large [...]

Thermodynamic theory is applied to study the effect of stress on the polarization of Bi4Ti3O12 films with a two-dimensional model. The spontaneous polarizations and free energies are calculated for three possible kinds of orientations of the Bi4Ti3O12 cell and nine ferroelectric phases in the Bi4Ti3O12 films. The stress effect on the spontaneous polarization caused by the lattice distortion is small and can be neglected for all the stable ferroelectric phases, whereas the domain reorientation induced by the competition between the external stress and a gradient intrinsic stress leads to a significant change of spontaneous polarization in Bi4Ti3O12 films. The calculation result agrees well with the experimental result on Nd-doped Bi4Ti3O12 films. [ABSTRACT FROM AUTHOR]

Presented here is a reality of virtual damage detection and vibration behaviour study of a discrete beam-like bridge with one or several non-propagating edge cracks subjected to a moving vehicle. In this model, the simply supported beam elements are replaced by a range of rigid bars, which are connected by transverse and rotational springs, while the mass and rotational moment of inertia may be lumped at various points along the beam. The adopted vehicle model here is a four degrees-of-freedom, two axes half-vehicle model with tires flexibility and linear suspensions. Damage can be modelled by altering the spring stiffness equation at the crack position according to predictions, which allows the inclusion of simple or complex damage. To simplify, damage is represented here by an open crack, and stiffness of a given element with damage is calculated by fracture mechanics. Both the discrete element and finite element methods are used to investigate vibration analysis of a discrete beam model subjected to a moving vehicle to confirm model feasibility in vibration analysis under a moving vehicle. Besides, some dynamic response laws are obtained. Considering an irregular road profile, the effects of the moving vehicle velocity, the moving vehicle mass, the crack location and the crack depth on dynamic response of a beam-like bridge are analysed by a numerical example, combining a vehicle-bridge coupled vibration MATLAB program with ANSYS. In addition, the neural network is used to identify the damage of the structure. Numerical results of the numerical model predictions, compared with those obtained from the continuous elements beam, support the accuracy of the discrete elements beam model in both cases of undamaged beam and damaged one. The evidence for condition assessment and damage identification of bridge is obtained from this simulation as obtaining the vibrational characteristics of the damaged beam structure subjected to a moving vehicle. And the inversion results show that the neural network method can identify the injury location and injury size of the structure accurately. [ABSTRACT FROM AUTHOR]

In order to improve the accuracy, efficiency and maneuverability of risk estimation of highway bridges, a response surface method and the improved Delphi method based framework for risk assessment of highway bridges is proposed. The flowchart of damage risk probability analysis of bridges based on response surface method is presented. The improved Delphi method is proposed to estimate the risk of highway bridges. The results of expert survey are adjusted by an optimization model, then the grade of risk loss is estimated quantificationally using the improved Delphi method. The damage risk assessment under earthquake of a self-anchored suspension bridge is carried out for illustrating the application and efficiency of the proposed methodology. The illustrative example indicates that not only the specific characteristics of the bridge but also the objective existence of uncertainty are considered by the response surface method based bridge damage probability estimation method, structural damage risk probability is calculated quantitatively taking full advantage of existing research results; The improved Delphi method overcomes the deficiencies of the traditional Delphi method, the statistical and computational workload are reduced while the reliability of expert opinions are ensured, so the time required for risk estimation is shortened to improve the efficiency of the risk assessment. [ABSTRACT FROM AUTHOR]

In order to verify the rationality and security of anchorage zone arrangement between beam and cable for a cable-stayed bridge with steel box girder, the stress state and distribution in anchorage zone of Hangzhou Bay Bridge was studied. The finite element simulation was employed to model the anchorage zone, the stress distribution of some structural members was investigated, and the load-carrying performance of this structure was evaluated. The results of simulation were verified by the reduced scale model test of anchorage zone for Hangzhou Bay Bridge with the scale of 1:3. The theoretical and experimental analyses indicate that the stress distribution and transimission for structural members in anchorage zone are are reasonable and smoothly with, satisfying carrying capacity. [ABSTRACT FROM AUTHOR]

In order to calculate the reliability of large scale civil structures without explicit performance functions, an artificial intelligence response surface method is proposed. The response surface was simulated by BP neural network, the genetic algorithm was applied to evaluate the reliability index, and the structure analysis was carried out by ANSYS. A program based on the proposed method was also developed by carrying out the mixed-language programming in Visual C + + 6.0, integrating standard APDL (Ansys Parametric Design Language) and GA as well as NN toolboxes in Matlab language. The validity of present program was verified by some numerical examples. The present method and program can be used to evaluate the reliability of complex structures with implicit performance functions. [ABSTRACT FROM AUTHOR]