β-receptor blocker influences return of spontaneous circulation and chemical examination in rats during cardiopulmonary resuscitation

Objective

We investigated the influence of β-receptor blocker metoprolol on return of spontaneous circulation (ROSC) during cardiopulmonary resuscitation (CPR) in rats with induced myocardial infarction (MI).

Methods

Male Sprague-Dawley rats were randomly divided into three groups: the sham-operated group, the MI group without metoprolol, which was fed the vehicle, and the MI+metoprolol group receiving intragastric metoprolol. Each group was further divided randomly into three subgroups, depending on the dosage of epinephrine administered during subsequent CPR applied after the induction of asphyxial cardiac arrest.

Results

The ROSC rate was significantly decreased in the low dose subgroup of MI group, unchanged in the medium dose subgroup of MI group, and significantly decreased in the high dose subgroup of MI group, compared with the same dose subgroup of sham-operated group. MI+metoprolol group had a lower ROSC rate than MI group in the medium dose subgroup, and a higher ROSC rate than MI group in the high dose subgroup. There was no difference in blood K⁺ values of successful rats between MI group and MI+metoprolol group. The rats with successful CPR had lower blood K⁺ values than rats with unsuccessful CPR in each of the three treatment groups.

Conclusions

Metoprolol administered to MI rats over a long period significantly improved ROSC rates under an appropriate dose of epinephrine during CPR. An increasing high blood K⁺ value would attenuate the rate of a successful CPR.     

层状硫化物中晶格失配对热电性能影响的理论研究

层状型的金属硫化物(SnS)1.2TiS2是一种新型的热电材料,其结构是由SnS层和TiS2层(一种自然超晶格)相叠加而形成.在这些热电材料中,发现了不同化合物的纳米化叠加态,由于这些沿层面叠加的超晶格的特殊性质,在不影响电子输运的情况下,可使声子的输运减小到最小,从而提升了材料的热电性能.计算了(SnS)1.2TiS2的电子结构与声子结构,通过对纯TiS2体材料与(SnS)1.2TiS2中的TiS2层的电子、声子结构的对比,证实了SnS插层对TiS2层的电子结构及电学输运性质影响很小.这些发现有利于提高层状材料的热电性能.     

Peoples of Melanesia

The mnemonic principles of the Dewey Decimal Classification were violated when Table 5 (Racial, Ethnic and National Groups) was introduced. Suggestions are presented to restore such principles to a large area of the South Pacific with particular reference to Melanesia.     

构建以自助服务为导向的现代图书馆

自助服务已经成为图书馆服务的一种重要形式.清华大学人文社科图书馆在建设之初就充分考虑了自助服务的需求,根据读者需求和自身特点,在实施了统一用户认证信息库、公告发布系统和电话咨询系统的基础上,提供了自助借还书、24小时自助还书窗口、自助缴纳超期罚款、自助文印服务、自助机位管理系统、自助研读间预订、自助阅览座位管理和开放密集架书库等服务,尝试构建一个以自助服务为导向的现代图书馆.     

A Vocabulary Learning Tool for L2 Undergraduates Reading Science and Technology Textbooks

Students of English as a second language who major in science and technology use English-language textbooks to ensure that they can read English materials upon graduation. Research indicates that teachers spend little time helping these students on the linguistic complexity of such textbooks. Vocabulary, grammar, and article structure are elements of this complexity, but to many students, these elements can be akin to locked doors. This study presents MyVLS-Reader, which focuses on unlocking the first of these doors—vocabulary—while assisting in reading. With explicit vocabulary learning, students learn and memorize individual vocabulary, but the context is lost if the depth of learning discards context. In implicit vocabulary learning, students acquire vocabulary through repeated exposure to contexts, but repeated encounters with new words are required. Few e-learning systems combine both vocabulary-learning approaches. MyVLS-Reader achieves such synergy by (1) using a keyword setting to provide context-matched vocabulary explanation while reading and (2) embedding multiple learning choices, such as keyword setting, the review and memorization of explicit vocabulary, and the option to ask instructors. This study includes two rounds of evaluations: (1) an evaluation of the learning achievements of control and treatment groups and (2) a quantitative and qualitative investigation of perceptions regarding the use of MyVLS-Reader. The evaluation results indicate that the treatment group developed a better vocabulary than the control group in significantly less time. The use of MyVLS-Reader also slightly improved higher-order thinking skills. This result suggests that MyVLS-Reader can effective assist students in building their vocabulary while reading.     

The educational expectations of Italian children: the role of social interactions with the children of immigrants

This paper aims to investigate to what extent the growing presence of children with immigrant background in the Italian school system has an impact on the educational expectations of Italian students in eighth grade. Educational expectations are individuals’ plans for their future educational career, adjusted to the subjectively estimated probabilities of achieving a given outcome. Multilevel analyses are performed using data from ITAGEN2 (Italian Second Generation) survey, the first nationwide survey on natives, first- and second-generation immigrants. Results demonstrate that attending a school with a high proportion of children of immigrants has no impact on realistic expectations about secondary education. In addition, students attending schools with high level of interethnic integration are more prone to having high educational expectations.     

一种蜂窝网络中支持D2D通信的资源分配方法

基于冲突图模型形成的二进制整数规划,提出了一种蜂窝网络中支持D2D通信的无线资源分配方法．首先,提出一种频率资源分配算法,即为每个D2D链路都分配一个频率资源块．分配频率资源时将尽可能地利用蜂窝网络中的无线频率资源空间重用机会．然后,提出一种时隙调度算法,即为所有分配同一频率资源块的D2D链路进行时隙资源调度．调度时隙资源时将保证使用同一频率资源块的D2D链路之间达到长期平均吞吐率的比例公平．通过计算机仿真对所提出方法的性能进行了验证,结果表明该方法能够在蜂窝网络中实现D2D通信功能．