Poly(1-vinyl-1,2,4-triazolium) poly(ionic liquid)s: synthesis and the unique behavior in loading metal ions

Herein we report the synthesis of a series of poly(4-alkyl-1-vinyl-1,2,4-triazolium) poly(ionic liquid)s either via straightforward free radical polymerization of their corresponding ionic liquid monomers, or via anion metathesis of the polymer precursors bearing halide as counter anion. The ionic liquid monomers were first prepared via N-alkylation reaction of commercially available 1-vinyl-1,2,4-triazole with alkyl iodides, followed by anion metathesis with targeted fluorinated anions. The thermal properties and solubilities of these poly(ionic liquid)s have been systematically investigated. Interestingly, it was found that the poly(4-ethyl-1-vinyl-1,2,4-triazolium) poly(ionic liquid) exhibited an improved loading capacity of transition metal ions in comparison with its imidazolium counterpart.Comment: 18 pages, 9 figure

Stable covalently photo-cross-linked poly(ionic liquid) membrane with gradient pore size

An imidazolium-based poly(ionic liquid) is covalently cross-linked via UV light-induced thiolene (click) chemistry to yield a stable porous polyelectrolyte membrane with gradients of crosslink density and pore size distribution along its cross-section.Comment: 16 pages, 10 figure

An unambiguous test of positivity at lepton colliders

The diphoton channel at lepton colliders, $e^+e^- (\mu^+\mu^-) \to \gamma \gamma$, has a remarkable feature that the leading new physics contribution comes only from dimension-eight operators. This contribution is subject to a set of positivity bounds, derived from fundamental principles of Quantum Field Theory, such as unitarity, locality and analyticity. These positivity bounds are thus applicable to the most direct observable -- the diphoton cross sections. This unique feature provides a clear, robust, and unambiguous test of these principles. We estimate the capability of various future lepton colliders in probing the dimension-eight operators and testing the positivity bounds in this channel. We show that positivity bounds can lift certain degeneracies among the effective operators and significantly change the perspectives of a global analysis. We also perform a combined analysis of the $\gamma\gamma/Z\gamma/ZZ$ processes in the high energy limit and point out the important interplay among them.Comment: 6 pages, 4 figure

Acculturative conservatism in immigrant naming

Thesis (S.M. in Management Research)--Massachusetts Institute of Technology, Sloan School of Management, 2013.Cataloged from PDF version of thesis.Includes bibliographical references (p. 26-28).Recent research on immigrant naming demonstrates a market tendency towards "acculturative conservatism," whereby immigrants select given names for their children that were highly popular in an earlier generation of the native population. Acculturative conservatism can potentially be explained as an attempt to address immigrants' feelings of insecurity by favoring cultural practices that most clearly convey the national identity. However, a more straightforward interpretation is that immigrants lack the necessary cultural capital to know which cultural practices are fashionable. In this paper, we first show that acculturative conservatism is a significant social force by examining how it lowered the rate of change in the fashion of given names between 1880 and 1920 in the United States. Second, we develop a novel analytic strategy to distinguish the effects of a lack of security and those of a lack of cultural capital. Our data include the English names of the early male children of Jewish immigrants who immigrated to America between 1880 and 1920, and the male names of the mainstream in the same period. By applying our analytic strategy, we find that Jewish immigrants tend to select among the formerly popular English names by favoring those whose popularity was still rising and to avoid those that were declining in the native population. This suggests that Jewish immigrants had considerable knowledge of the latest fashions, but deliberately chose older names that would convey their national identity more strongly and thereby address their feelings of insecurity.by Jiayin Zhang.S.M.in Management Researc

BubR1 and APC/EB1 cooperate to maintain metaphase chromosome alignment

The accurate segregation of chromosomes in mitosis requires the stable attachment of microtubules to kinetochores. The details of this complex and dynamic process are poorly understood. In this study, we report the interaction of a kinetochore-associated mitotic checkpoint kinase, BubR1, with two microtubule plus end–associated proteins, adenomatous polyposis coli (APC) and EB1, providing a potential link in stable kinetochore microtubule attachment. Using immunodepletion from and antibody addition to Xenopus laevis egg extracts, we show that BubR1 and its kinase activity are essential for positioning chromosomes at the metaphase plate. BubR1 associates with APC and EB1 in egg extracts, and the complex formation is necessary for metaphase chromosome alignment. Using purified components, BubR1 directly phosphorylates APC and forms a ternary complex with APC and microtubules. These findings support a model in which BubR1 kinase may directly regulate APC function involved in stable kinetochore microtubule attachment

When Politics Froze Fashion: The Effect of the Cultural Revolution on Naming in Beijing

The authors examine the popularity of boys’ given names in Beijing before and after the onset of the Cultural Revolution to clarify how exogenous and endogenous factors interact to shape fashion. Whereas recent work in the sociology of culture emphasizes the importance of endogenous processes in explaining fashion, their analysis demonstrates two ways in which politics shaped cultural expression during the Cultural Revolution: by promoting forms of expression reflecting prevailing political ideology and by limiting individuals’ willingness to act differently. As argued by Lieberson and developed further in this article, the second condition is important because endogenous fashion cycles require a critical mass of individuals who seek to differentiate themselves from common practice. Exogenous factors can influence the operation of the endogenous factors. The authors discuss the implications of their study for understanding the nature of conformity under authoritarian regimes and social conditions supporting individual expression

A Lack of Security or of Cultural Capital? Acculturative Conservatism in the Naming Choices of Early 20th-Century US Jews

Past research demonstrates a marked tendency toward “acculturative conservatism,” whereby immigrants select given names for their children that are established—that is, popular in an earlier generation of the native population. Prior research has generally understood such conservatism as reflecting a lack of “mainstream” cultural capital; established names are popular among immigrants because they are unaware of current fashion. But we argue and show that even when they are aware of current fashion, immigrants may favor established names to affirm their membership in the host society. Comparing given names among World War II Jewish servicemen (born around 1918) with given names in the general US population in 1920, we show that the parents of these servicemen exhibited a pattern of acculturation that was (1) selective (in avoiding popular native names with strong Christian associations, and embracing certain unpopular native names) and (2) conservative (in their tendency to favor established names relative to newly popular names). In addition, our key finding is that these parents favored those established names whose popularity was rising and avoided those whose popularity was declining. This suggests that Jewish immigrants were aware of mainstream fashion, but deliberately chose established names so as to express their membership in American society. More generally, this result indicates that the acculturation process is as much about gaining social acceptance as about becoming adept in the mainstream culture