静脉输注国产声学造影剂定量心肌血流灌注的实验研究

目的：评价应用国产左心声学造影剂“全氟星”定量心肌血流灌注的可行性。方法：建立犬前降支缺血模型，经外周静脉持续匀速输注“全氟星”，存取不同触发间隔的造影图像，通过计算造影剂再充填曲线的平台声强度及微泡再充填速率估测心肌血流量。以正常区为参照、放射微球测定心肌血流量为“金标准”，判定应用国产左心声学造影剂定量心肌血流灌注的可行性。结果：放射微球测定心肌血流量与心肌声学造影定量结果相关良好（r=0.8913，P＜0．001）。结论：静脉均速输注“全氟显”可用于估测心肌血流量。     

自制脂膜氟碳声学造影剂增强兔颅内肿瘤彩色血流显像的实验研究

目的 观察自制脂膜氟碳声学造影“脂氟显”对家兔颅内肿瘤彩色血流信号显像的增强作用。方法 5只颅内种植VX2肿瘤的家兔经耳缘静脉团注0．01ml/kg“脂氟显”，动态观察颅内肿瘤彩色血流显像的增强效果。结果“脂氟显”对家兔颅内肿瘤彩色血流显像有明显增强效果，且持续时间长。结论 “脂氟显”能明显、长时间地增强家兔颅内肿瘤的彩色血流显像，有助于了解颅内占位情况。     

甲状腺乳头状癌超声造影定量参数与微血管密度的相关性

目的 探讨甲状腺乳头状癌（PTC）超声造影定量参数与病理微血管密度（MVD）的相关性。方法 回顾性分析33例PTC患者（共36枚结节）术前常规超声及超声造影检查的声像图资料。应用Qlab软件绘制结节边缘及中心区域时间-强度曲线（TIC）,获得不同部位的超声造影定量参数值,包括峰值强度和曲线下面积;术后对标本均进行CD31因子免疫组化染色,并分别计算结节边缘区域及中心区域的MVD,并分析上述超声造影定量参数与MVD的相关性。结果 PTC结节整体呈不均匀低增强,结节边缘区域增强程度多高于中心区域。PTC结节边缘区域RT、PI、AUC及MVD分别为（3.24±2.10sec、7.84±2.55dB、182.63±87.83dB sec、35.09±9.61条/HP）,均高于结节中心（2.42±1.93sec、4.01±2.36dB、89.90±54.67dB sec、15.97±6.07条/HP）,差异均有统计学意义（均P＜0.05）。PTC结节边缘区域的峰值强度和曲线下面积与边缘区域MVD均呈正相关（r= 0.831,P=0.000;r= 0.705,P=0.000）;PTC结节中心区域的峰值强度和曲线下面积与中心区域MVD之间均呈正相关（r= 0.678,P=0.000;r= 0.684,P=0.000）。结论 PTC结节的超声造影定量参数峰值强度和曲线下面积能反映PTC不同部位组织的MVD,CEUS可作为术前评估PTC结节MVD的无创性方法。     

螯合剂与金属硫蛋白对铀的竞争结合作用

目的 通过探讨螯合剂与金属硫蛋白（MT）竞争结合铀（U）（VI）的作用,建立铀促排螯合剂体外筛选的新方法。方法 采用竞争ELISA法,96孔酶标板经MT抗原包被、U（VI）或Zn²⁺预处理、螯合剂（CBMIDA-CaNa₂、BPCBG和DTPA-CaNa₃）处理、MT抗体免疫结合、HRP偶联二抗结合及OPD显色反应后,在波长490 nm处检测吸光度值以评价螯合剂与MT竞争结合U（VI）、Zn²⁺的能力。结果 本反应体系的吸光度值随MT质量浓度和MT抗体浓度增加而增加,其中最佳MT抗原包被浓度和MT抗体浓度均为2 μg/mL。与Zn²⁺的作用相似,U（VI）亦可使反应体系的吸光度值随其浓度增加而降低,其中最佳U（VI）和Zn²⁺浓度均为300 μg/mL。加入CBMIDA-CaNa₂和BPCBG则能明显提高U（VI）处理体系的吸光度值,CBMIDA-CaNa₂的作用强于BPCBG,而DTPA-CaNa₃则无明显作用;各螯合剂与MT竞争结合U（VI）能力的强弱顺序与以往细胞和动物U（VI）促排实验的结果相吻合。这3种螯合剂对Zn²⁺处理体系的吸光度值均无明显影响。结论 CBMIDA-CaNa₂和BPCBG能有效竞争结合于MT上的U（VI）,DTPA-CaNa₃无明显作用,竞争ELISA法可作为体外筛选U（VI）促排螯合剂的方法,具有简便、快速和高通量的优势。     

The spatial ecology of alcohol problems: niche theory and assortative drinking

Aims This paper summarizes several theoretical perspectives that serve to explain observed associations between concentrations of alcohol outlets and alcohol‐related problems. A critique of each perspective discusses how each addresses the social etiology of these problems; that is, how, where and why these problems arise in association with alcohol outlets? Methods This theoretical work is based upon mathematical and computational models of the ecology of alcohol‐related problems developed in the ‘Ecosystems Modeling Project’, an advanced research project of the National Institute on Alcohol Abuse and Alcoholism, United States. Results Associations between outlets and problems are thought to arise from the concentration of individuals in drinking places (‘flow models’), the attraction of some places for people at risk for problems (‘gravity models’), or because outlets are located in high‐risk neighborhoods and have negative social normative effects (‘social contextual models’). None of these approaches explain how some outlets come to have more problems than others (e.g. violent outlets). An alternative social ecological model is introduced which asserts that the complementary processes of niche marketing and assortative drinking form the social dynamic that explains these relationships. Alcohol sellers ‘niche market’ to select social strata, drinkers return to establishments at which they find people like themselves, and consequent social stratification of the market‐place increases the levels of related problems in some outlets. Conclusions The proposed mechanism is very general, and suggests that over‐concentrations of outlets will lead to stratification of drinking groups and intensification of problems related to those outlets.     

Modeling the Emergence of Lexicons in Homesign Systems

It is largely acknowledged that natural languages emerge not just from human brains but also from rich communities of interacting human brains (Senghas, 2005). Yet the precise role of such communities and such interaction in the emergence of core properties of language has largely gone uninvestigated in naturally emerging systems, leaving the few existing computational investigations of this issue at an artificial setting. Here, we take a step toward investigating the precise role of community structure in the emergence of linguistic conventions with both naturalistic empirical data and computational modeling. We first show conventionalization of lexicons in two different classes of naturally emerging signed systems: (a) protolinguistic “homesigns” invented by linguistically isolated Deaf individuals, and (b) a natural sign language emerging in a recently formed rich Deaf community. We find that the latter conventionalized faster than the former. Second, we model conventionalization as a population of interacting individuals who adjust their probability of sign use in response to other individuals' actual sign use, following an independently motivated model of language learning (Yang, 2002, 2004). Simulations suggest that a richer social network, like that of natural (signed) languages, conventionalizes faster than a sparser social network, like that of homesign systems. We discuss our behavioral and computational results in light of other work on language emergence, and other work of behavior on complex networks.     

How Communication Can Make Voters Choose Less Well

With the advent of social media, the last decade has seen profound changes to the way people receive information. This has fueled a debate about the ways (if any) changes to the nature of our information networks might be affecting voters’ beliefs about the world, voting results, and, ultimately, democracy. At the same time, much discussion in the public arena in recent years has concerned the notion that ill‐informed voters have been voting against their own self‐interest. The research reported here brings these two strands together: simulations involving agent‐based models, interpreted through the formal framework of Condorcet's (1785) jury theorem, demonstrate how changes to information networks may make voter error more likely, even though individual competence has largely remained unchanged.     

Agent computing themes in biologically inspired models of learning and development

After evaluating general features and attributes of the agent notion, the overlap of features in candidate (attribute) cores, and several less central features, the paper addresses agent and related theory in neuroscience, observing how agent notions have penetrated portions of this field and how the field itself emphasizes and further develops some agent themes via, e.g. schema theory, neural net-artificial intelligence (AI) comparisons, and other research. In remaining sections, models for development of memory strategies in children are presented, illustrating cooperative and competitive neural modeling agents, an active role for a "human agent in the loop," and integrating broadly-based neural network (NN) modeling with other bio-inspired models.     

电子商务中基于社会交换的谈判

以Agent为中介的电子商务研究忽略了社会关系等社会因素对Agent的谈判的影响.本文在分析价值交换和相应的谈判过程中的社会关系基础上,将基于社会关系的谈判与一种扩展价值交换相联结,提出了一种基于价值交换的谈判的理论框架及其实现机制.