Craniocerebral injury promotes the repair of peripheral nerve injury

The increase in neurotrophic factors after craniocerebral injury has been shown to promote fracture healing. Moreover, neurotrophic factors play a key role in the regeneration and repair of peripheral nerve. However, whether craniocerebral injury alters the repair of peripheral nerve injuries remains poorly understood. Rat injury models were established by transecting the left sciatic nerve and using a free-fall device to induce craniocerebral injury. Compared with sciat- ic nerve injury alone after 6-12 weeks, rats with combined sciatic and craniocerebral injuries showed decreased sciatic functional index, increased recovery of gastrocnemius muscle wet weight, recovery of sciatic nerve ganglia and corresponding spinal cord segment neuron mor- phologies, and increased numbers of horseradish peroxidase-labeled cells. These results indicate that craniocerebral injury promotes the repair of peripheral nerve injury.

Sericin can reduce hippocampal neuronal apoptosis by activating the Akt signal transduction pathway in a rat model of diabetes mellitus

In the present study, a rat model of type 2 diabetes mellitus was established by continuous peritoneal injection of streptozotocin. Following intragastric perfusion of sericin for 35 days, blood glucose levels significantly reduced, neuronal apoptosis in the hippocampal CA1 region decreased, hippocampal phosphorylated Akt and nuclear factor kappa B expression were enhanced, but Bcl-xL/Bcl-2 associated death promoter expression decreased. Results demonstrated that sericin can reduce hippocampal neuronal apoptosis in a rat model of diabetes mellitus by regulating abnormal changes in the Akt signal transduction pathway.

Estrogen intervention in microvascular morphology and choline acetyltransferase expression in rat hippocampal neurons in chronic cerebral ischemia

We observed dynamic changes in microvessels and a protective effect of estrogen on chronic cerebral ischemia ovariectomized rat models established through permanent occlusion of bilateral carotid arteries at 7, 14 and 21 days. The results revealed that estrogen improved microvasculature in the hippocampus of chronic cerebral ischemic rats, upregulated Bcl-2 protein expression, downregulated Bax protein expression, increased choline acetyltransferase expression in hippocampal cholinergic neurons, and suppressed hippocampal neuronal apoptosis. These findings indicate that estrogen can protect hippocampal neurons in rats with chronic cerebral ischemia.

Altered acetylcholinesterase levels in the spinal cord anterior horn and dorsal root ganglion following sciatic nerve ischemia

BACKGROUND： Peripheral nerve ischemia has been shown to result in ischemic fiber degenera-tion and axoplasmic transport disturbance. However, the effect on acetylcholinesterase （AChE） ex- pression in relevant cells following sciatic nerve ischemia remains unclear. OBJECTIVE： To observe AChE concentration changes following peripheral nerve ischemia. DESIGN, TIME AND SETTING： The present comparative observation, neuroanatomical experiment was performed at the Central Laboratory Animal of Chengde Medical College between 2006 and 2007. MATERIALS： A total of 20 healthy, adult, Wistar rats were randomized into two groups （n = 10）： 8-day ischemia and 14-day ischemia. METHODS： Ischemia injury was induced in the unilateral sciatic nerve （experimental side） through ligation of the common iliac artery. The contralateral side received no intervention, and served as the control side. Rats in the 8-day ischemia and 14-day ischemia groups were allowed to survive for 8 and 14 days, respectively. MAIN OUTCOME MEASURES： The L5 lumbar spinal cord and the L5 dorsal root ganglion were removed from both sides and sectioned utilizing a Leica vibrating slicer. AChE cellular expression was detected using Karnovsky-Root, and the number of AChE-positive cells and average gray value were analyzed using a MiVnt image analysis system. RESULTS： In the 8-day ischemia group, AChE-positive cell numbers were significantly less in the dorsal root ganglion and spinal cord anterior horn of the experimental side, but the average gray value was significantly greater, compared with the control side （P 〈 0.05）. These changes were more significant in the 14-day ischemia group than in the 8-day ischemia group （P 〈 0.01）. CONCLUSION： Peripheral nerve ischemia leads to decreased AChE expression in the associated cells in a time-dependent manner.

A Practical Online Approach to Protecting Kernel Heap Buffers in Kernel Modules

Heap overflow attack is one of the major memory corruption attacks that have become prevalent for decades. To defeat this attack,many protection methods are proposed in recent years. However,most of these existing methods focus on user-level heap overflow detection. Only a few methods are proposed for kernel heap protection. Moreover,all these kernel protection methods need modifying the existing OS kernel so that they may not be adopted in practice. To address this problem,we propose a lightweight virtualization-based solution that can protect the kernel heap buffers allocated for the target kernel modules. The key idea of our approach is to combine the static binary analysis and virtualization technology to trap a memory allocation operation of the target kernel module,and then add one secure canary word to the end of the allocated buffer. After that,a monitor process is launched to check the integrity of the canaries. The evaluations show that our system can detect kernel heap overflow attacks effectively with minimal performance cost.

Design and validation of a variable camber wing structure

Variable camber wing technology is one of the important development trends of green aviation at present.Through smooth,seamless,continuous and adaptive change of wing camber,the aerodynamic performance is improved in achieving increase in lift and reduction in resistance and noise.Based on the aerodynamic validation model CAE-AVM,Chinese Aeronautical Establishment(CAE)has carried out the design and validation of a variable camber wing,proposed an aerodynamic deformation matrix for the leading and trailing edges of aircraft wings in takeoff,landing and cruise conditions.Various structures and driving schemes are compared,and several key technology problems of leading and trailing edge deformation are solved.A full-size leading edge wind tunnel test piece with a span of 2.7 m and a trailing edge ground function test piece are developed.The deformation and shape maintenance capabilities of the leading edge is verified under real wind load conditions,and the load bearing and deformation capabilities of the trailing edge is verified under simulated follow-on load.The results indicate that the leading and trailing edges of the variable camber wing can achieve the required deformation angle and have a certain load-bearing capacity.Our study can provide some insights into the application of variable camber wing technology for civil aircraft.

Test Data Generation for Stateful Network Protocol Fuzzing Using a Rule-Based State Machine

To improve the efficiency and coverage of stateful network protocol fuzzing, this paper proposes a new method, using a rule-based state machine and a stateful rule tree to guide the generation of fuzz testing data. The method first builds a rule-based state machine model as a formal description of the states of a network protocol. This removes safety paths, to cut down the scale of the state space. Then it uses a stateful rule tree to describe the relationship between states and messages, and then remove useless items from it. According to the message sequence obtained by the analysis of paths using the stateful rule tree and the protocol specification, an abstract data model of test case generation is defined. The fuzz testing data is produced by various generation algorithms through filling data in the fields of the data model. Using the rule-based state machine and the stateful rule tree, the quantity of test data can be reduced. Experimental results indicate that our method can discover the same vulnerabilities as traditional approaches, using less test data, while optimizing test data generation and improving test efficiency.

Semi-valid Fuzz Testing Case Generation for Stateful Network Protocol

Network protocols are divided into stateless and stateful. Stateful network protocols have complex communication interactions and state transitions. However, the existing network protocol fuzzing does not support state transitions very well. This paper focuses on this issue and proposes the Semi-valid Fuzzing for the Stateful Network Protocol （SFSNP）. The SFSNP analyzes protocol interactions and builds an extended finite state machine with a path marker for the network protocol; then it obtains test sequences of the extended finite state machine, and further performs the mutation operation using the semi-valid algorithm for each state transition in the test sequences; finally, it obtains fuzzing sequences. Moreover, because different test sequences may have the same state transitions, the SFSNP uses the state transition marking algorithm to reduce redundant test cases. By using the stateful rule tree of the protocol, the SFSNP extracts the constraints in the protocol specifications to construct semi-valid fuzz testing cases within the sub-protocol domain, and finally forms fuzzing sequences. Experimental results indicate that the SFSNP is reasonably effective at reducing the quantity of generated test cases and improving the quality of fuzz testing cases. The SFSNP can reduce redundancy and shorten testing time.

An Improved ID-Based Group Key Agreement Protocol

ID-based constant-round group key agreement protocols are efficient in both computation and communication, but previous protocols did not provide valid message authentication. An improvement based on attack analysis is proposed in this paper. The improved method takes full advantage of the data transmitted at various stages of the protocol. By guaranteeing the freshness of authentication messages, the authenticity of the generator of authentication messages, and the completeness of the authenticator, the improved protocol can resist various passive and active attacks. The forward secrecy of the improved protocol is proved under a Katz-Yung （KY） model. Compared with existing methods, the improved protocol is more effective and applicable.

Software System Evolution Analysis Method Based on Algebraic Topology

The analysis of software system evolution is highly significant in software research as the evolution runs throughout the lifecycle of a software system. Considering a software system as an algebraic engineering system, we propose a software system evolution analysis method based on algebraic topology. First, from a complex network perspective, we abstract a software system into the software structural topology diagram. Then, based on the algebraic topology principle, we abstract each node in the software structural topology diagram into an algebraic component represented by a 6-tuple. We propose three kinds of operation relationships between two algebraic components, so that the software system can be abstracted into an algebraic expression of components. In addition, we propose three forms of software system evolution, which help to analyze the structure and evolution of system software and facilitate its maintenance and reconfiguration.