Protective Effect of Mulberry Extract against Pb-induced Learning and Memory Deficits in Mice

Lead （Pb） is ubiquitous in the environment, and low-level Pb exposure can cause neurotoxicity and irreversible damage to children＇s cognition, learning and memory ability. Nutritional intervention is an effective method to prevent Pb poisoning. Mul- berry is rich in anthocyanins, possessing protective effects for nerves. This study investigated the neuroprotective effects of mulberry extract （ME） against Pb-induced learning and memory deficits in mice. The results showed that the learning and memory abilities of mice, assessed using the Morris test, improved significantly after treatment with ME at a dose of 100 mg/kg body weight. The level of Pb in the brains of mice in the three ME intervention groups decreased significantly, while NO production and anti-oxidant enzymes were significantly restored. It is suggested that ME inhibits Pb-induced neurotoxicity by reversing Pb-induced alterations in the aspect of neurotoxic effects and improving learning and memory.

A Protective Mechanism for the Access Control System in the Virtual Domain

In traditional framework,mandatory access control(MAC) system and malicious software are run in kernel mode. Malicious software can stop MAC systems to be started and make it do invalid. This problem cannot be solved under the traditional framework if the operating system(OS) is comprised since malwares are running in ring 0 level. In this paper,we propose a novel way to use hypervisors to protect kernel integrity and the access control system in commodity operating systems. We separate the access control system into three parts: policy management(PM),security server(SS) and policy enforcement(PE). Policy management and the security server reside in the security domain to protect them against malware and the isolation feather of the hypervisor can protect them from attacks. We add an access vector cache(AVC) between SS and PE in the guest OS,in order to speed up communication between the guest OS and the security domain. The policy enforcement module is retained in the guest OS for performance. The security of AVC and PE can be ensured by using a memory protection mechanism. The goal of protecting the OS kernel is to ensure the security of the execution path. We implementthe system by a modified Xen hypervisor. The result shows that we can secure the security of the access control system in the guest OS with no overhead compared with modules in the latter. Our system offers a centralized security policy for virtual domains in virtual machine environments.Keywords: hypervisor; virtualization; memo-

A Scheme of Memory Privacy Protection in Cloud Computing Environment

With the popularity and commercialization of cloud computing platforms, the security of virtualization technology must be guaranteed. The paper studies the protection of memory privacy under virtual platform to enhance system security. Based on the monitoring of foreign mapping for Dom0, a memory privacy protection scheme is designed and implemented to prevent process memory pages in DomU being mapped illegally which might result in the leakage of secret data.