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To investigate the role of pH2AX in the reversibility of mouse testicular reproductive function impaired by single heat stress.Twenty-four C57 male mice were randomly divided into heat stress and control groups and immersed in water at 43℃ and 25℃, respectively, for 15 minutes. At 1, 7, and 14 days of heat exposure, all the mice were sacrificed and their testis tissues collected for determining the apoptosis of the germ cells by TUNEL and measuring the expression level of the pH2AX protein by immunohistochemistry and Western blot.The highest percentage of apoptotic cells were found in the seminiferous tubules of the mice in the heat stress group on the 1st day of the exposure and almost no apoptosis was observed at 7 and 14 days. The pH2AX protein was expressed in the nuclei of the basement membrane of adjacent seminiferous tubules. Compared with the control group, the expression of pH2AX was significantly increased on the 1st day of exposure (0.47 ± 0.02 vs 1.61 ± 0.04, P0.01), then decreased at 7 days (0.85 ± 0.03) in comparison with that on the 1st day (P0.01), and again elevated at 14 days (1.72 ± 0.02) as compared with either those at 1 and 7 days (P0.01) or that of the control (P0.01).Heat stress causes dynamic changes of the pH2AX expression in the testis of the mouse, which are associated with heat stress-induced proliferation and division of the testicular spermatogenic cells.目的： 探讨pH2AX在单次热应激致小鼠睾丸生殖功能可逆性中的表达变化。方法： C57雄性小鼠24只，随机按1、7、14 d分为对照组(n = 6)和热应激组(n = 6)。热应激组和对照组小鼠下腹部分别置于43 ℃和25 ℃水浴中干预15 min，于处理后1、7、14 d 取睾丸组织。TUNEL检测睾丸细胞凋亡情况，免疫组化染色检测pH2AX蛋白定位及表达，Western 印迹检测pH2AX蛋白表达水平。结果： TUNEL结果显示，在热应激后的第1天生精小管中的凋亡细胞数量最多，第7、14天细胞凋亡基本消失。免疫组化显示，pH2AX蛋白在睾丸生精小管基底膜处细胞核表达。Western印迹检测显示，与对照组相比，热应激后的第1天，pH2AX蛋白表达明显增加（0.47±0.02 vs 1.61±0.04，P0.01）；第7天（0.85±0.03）与热应激处理第1天相比pH2AX蛋白表达显著减少（P0.01）；第14天（1.72±0.02）与热应激处理第1、7天及对照组相比pH2AX蛋白表达显著增加（P均0.01）。结论： 小鼠睾丸热应激处理后pH2AX蛋白表达量在睾丸中出现动态变化，这种变化与热应激后睾丸生精细胞的增殖分裂相关。.

IPv4 and IPv6 will coexist for a long time, due to ISPes’ inertia in the transition from IPv4 to IPv6. Domain Name System (DNS) is a very important functional unit in the Internet. This paper describres the hierarchy and operating process of IPv6 DNS, IPv6 DNS resolver, and presents the DNS transition from IPv4 to IPv6 in particular. We suggest two methods to implement DNS service during the transition period: DNS-Application Level Gateway (DNS-ALG) with Network Address Translation-Protocol Translation (NAT-PT), and dual stacks. And we also propose their respective operational principles. This paper is of valuable reference for network engineers to construct DNS in the transition phase.

With the rapid development of computer and network technology, our everyday life is more and more influenced. In the information age it is an inevitable trend that consumer electronics will become more and more intelligentized and interconnected. Taking into account the characteristics of external network users’ access to a home networking, as well as the important role that the residential gateway plays in the interaction between external networks and home networking, this paper presents the idea of a unique access interface of the home networking. Furthermore, this paper designs and implements an IPv6-based UPnP real-time video and audio capture device, and the real-time audio/video stream captured is forwarded to external network users through the residential gateway. Other multimedia applications can be resolved in the same way.

Our home is becoming more and more intelligentized. In the home network, the residential gateway plays a key role in the data interchange between external networks and home network, this paper proposes an idea that the home network should guarantee a unique visiting interface. Furthermore, this paper designs and implements the central forwarding mechanism of the residential gateway, and exchanges between outer networks and home network must be through the residential gateway. This paper is of valuable reference for network researchers and engineers to be engaged in the further study on the home network.

IP traceback can be used to confirm locations of attackers, stop on-going attacks, and take legal actions against attackers, and then impede attackers. This paper describes the background where IP traceback problem generates, and presents what the functions of IP traceback are. Furthermore, this paper classifies existing IP traceback methods and analyzes advantages and disadvantages of each method. In addition, future researches on IP traceback are proposed. This paper is of valuable reference for network researchers and engineers to be engaged in the further study on IP traceback.

IPv6 is intended to replace IPv4 in the Internet. Domain Name System (DNS) is an essential component of functionality of Internet. This paper presents new IPv6 characteristics, IPv6 DNS hierarchy, working process of IPv6 DNS, IPv6 address types, representation formats of IPv6 address, forward (reverse) resolver of IPv6 DNS, and the DNS transition from IPv4 to IPv6, combined with the practice to build the IPv6 experimental network of Peking University. We give corresponding solutions for the problems encountered in the IPv6 DNS deployment. This paper is of important reference value for IPv6 network researchers and engineers to build IPv6 DNS service in the IPv6 network.

To investigate the effects of single heat stress treatment on spermatogenic cells in mice.We randomly divided 36 C57 male mice into a control and a heat stress treatment group and submerged the lower part of the torso in water at 25 °C and 43 °C, respectively, both for 15 minutes. At 1, 7, and 14 days after treatment, we obtained the testicular organ indexes, observed the changes in testicular morphology by HE staining, and determined the location and expression levels of the promyelocytic leukemia zinc finger (PLZF) and synaptonemal comlex protein-3 (SCP-3) in the testis tissue by immunohistochemistry and Western blot.The testicular organ index was significantly lower in the heat stress treatment than in the control group (P0.05). Compared with the controls, the heat shock-treated mice showed loosely arranged spermatogenic cells scattered in the seminiferous tubules at 1 day after heat stress treatment, atrophied, loosely arranged and obviously reduced number of spermatogenic cells at 7 days, and relatively closely arranged seminiferous tubules and increased number and layers of spermatogenic cells at 14 days. The number of SCP-3 labelled spermatocytes obviously decreased in the heat stress-treated animals at 1 and 7 days and began to increase at 14 days. The PLZF protein expression was significantly reduced in the heat stress treatment group at 1 day as compared with that in the control (0.19 ± 0.12 vs 0.64 ± 0.03, P0.01), but elevated to 0.77 ± 0.02 at 7 and 14 days, even remarkably higher than in the control animals (P0.01).Heat stress treatment can induce short-term dyszoospermia in mice, which can be recovered with the prolonged time after treatment.