Effect of grafting density on local dynamics in functionalized polymer-grafted nanoparticle systems

This article explores the relations between a foreign aid donor and local actors in the context of the dissemination of development discourses and practices in an authoritarian context. It addresses the question “To what extent may the local dynamics alter the original goals of a donor and lead to unintended consequences?” Based on archival research, interviews, and secondary literature, this case study examines the Yunnan Uplands Management Project (YUM) in 1990–95, the Ford Foundation's first grant program on rural poverty alleviation in China. While the Foundation did not attain its main goal of making YUM a national model for poverty alleviation, the local actors were able to use YUM to develop individual capacities and to build roles for themselves as development actors in the form of associations and nongovernmental organizations, resulting in further support from the Foundation. The study contributes to our understanding of donor-local actor dynamics by highlighting the gaps between the original goals of a donor and the perspectives and motivations of local actors. The study suggests that local dynamics may influence the goals of donors and the ways they seek to disseminate development discourses and practices to local actors, despite the common conception of donors as hegemonic or culturally imperialistic.

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SHORT-TERM DYNAMICS OF THE ANAPA BAY-BAR SHORELINE

Proceedings of International Conference "Managinag risks to coastal regions and communities in a changinag world" (EMECS'11 - SeaCoasts XXVI) ◽

10.31519/conferencearticle_5b1b9484d73d71.24844503 ◽

2017 ◽

Author(s):

Marina Krylenko ◽

Alexandr Aleynikov ◽

Viacheslav Krylenko ◽

...

Keyword(s):

Black Sea ◽

Satellite Images ◽

The Black Sea ◽

Northwestern Part ◽

Short Term ◽

Shoreline Position ◽

Local Dynamics ◽

Average Displacement ◽

Local Erosion

The Anapa bay-bar is located in the northwestern part of the Black Sea. With the goal in mind to determine the short-term dynamics of the Anapa bay-bar we analyzed satellite images from 2003 to the present. Depending on the hydro-lithodynamical situation the shoreline configuration during storm can vary from a rectilinear to sinusoidal forms. There are regions of local erosion or accumulation whose formation is related to the alongshore motion of sediments and dynamics of underwater bars. Comparison of the data on 1965 and 1966 showed that in this period the amplitude of the shoreline position was more than 20 m but average displacement of the shoreline for 13 months was only 0.8 m. This study showed that for the analysis of changes in the shoreline position is necessary to consider the configuration of the coastline at the time of each observation and the local dynamics.

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Transdisciplinarity

The Oxford Handbook of Global Studies ◽

10.1093/oxfordhb/9780190630577.013.29 ◽

2018 ◽

pp. 126-138

Author(s):

James Mittelman ◽

Daniel Esser

Keyword(s):

Social Science ◽

Methodological Approach ◽

Building Blocks ◽

Transdisciplinary Research ◽

Global Studies ◽

Local Dynamics ◽

Research And Teaching ◽

Methodological Rigor ◽

Interdisciplinary Scholarship ◽

Science Disciplines

This chapter assesses transdisciplinarity as an epistemological and methodological approach to research and teaching in the emerging field of global studies. It posits that the world’s most pressing problems in the areas of migration, health, and intersectional identities, to name a few, are unlikely to be addressed convincingly by inquiries rooted exclusively in singular social science disciplines. At the same time, transdisciplinarity is understood as a means to complement disciplinary research, not to dispense with it. By foregrounding global–local dynamics and their effects across scales, global studies can draw from a wealth of approaches and experiences in interdisciplinary scholarship without becoming entangled in protracted epistemological battles over scholarly turf. This chapter then provides examples of transdisciplinary research in global studies and closes by stressing the importance of disciplinary methodological innovations as building blocks for multimodal designs and arguing for methodological rigor in global studies, whether transdisciplinary or not.

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Bottlebrush polymers in the melt and polyelectrolytes in solution share common structural features

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1916362117 ◽

2020 ◽

Vol 117 (10) ◽

pp. 5168-5175 ◽

Cited By ~ 4

Author(s):

Joel M. Sarapas ◽

Tyler B. Martin ◽

Alexandros Chremos ◽

Jack F. Douglas ◽

Kathryn L. Beers

Keyword(s):

Neutron Scattering ◽

Correlation Length ◽

Salt Concentration ◽

Polymer Concentration ◽

Structural Features ◽

Peak Position ◽

Correlation Peak ◽

Grafting Density ◽

Scattering Measurements ◽

Polyelectrolyte Solutions

Uncharged bottlebrush polymer melts and highly charged polyelectrolytes in solution exhibit correlation peaks in scattering measurements and simulations. Given the striking superficial similarities of these scattering features, there may be a deeper structural interrelationship in these chemically different classes of materials. Correspondingly, we constructed a library of isotopically labeled bottlebrush molecules and measured the bottlebrush correlation peak position q*=2π/ξ by neutron scattering and in simulations. We find that the correlation length scales with the backbone concentration, ξ∼cBB−0.47, in striking accord with the scaling of ξ with polymer concentration cP in semidilute polyelectrolyte solutions (ξ∼cP−1/2). The bottlebrush correlation peak broadens with decreasing grafting density, similar to increasing salt concentration in polyelectrolyte solutions. ξ also scales with sidechain length to a power in the range of 0.35–0.44, suggesting that the sidechains are relatively collapsed in comparison to the bristlelike configurations often imagined for bottlebrush polymers.

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Světlana: Partisans and Power in Post-War Czechoslovakia

Contemporary European History ◽

10.1017/s0960777320000508 ◽

2021 ◽

Vol 30 (1) ◽

pp. 16-31

Author(s):

Mira Markham

Keyword(s):

Early Years ◽

Communist Regime ◽

Rural Region ◽

Local Dynamics ◽

Resistance Network ◽

Official Ideology ◽

Post War

After the renewal of national independence in 1945 former anti-fascist partisans were among the Czechoslovak Communist Party's most reliable and radical allies. Nevertheless, following the communist coup of 1948, a group of partisans in the rural region of Moravian Wallachia began to mobilise wartime networks and tactics against the consolidating party dictatorship, establishing the Světlana resistance network. Simultaneously, state authorities also drew on partisan practices to reconstitute opposition and resistance in this region as evidence of an international conspiracy that could be understood and prosecuted within the framework of official ideology and propaganda. This article analyses the case of Světlana to examine the politics of people's democracy in Czechoslovakia and explore local dynamics of resistance and repression during the early years of the communist regime.

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Effects of Amino Acid Side-Chain Length and Chemical Structure on Anionic Polyglutamic and Polyaspartic Acid Cellulose-Based Polyelectrolyte Brushes

Polymers ◽

10.3390/polym13111789 ◽

2021 ◽

Vol 13 (11) ◽

pp. 1789

Author(s):

Dmitry Tolmachev ◽

George Mamistvalov ◽

Natalia Lukasheva ◽

Sergey Larin ◽

Mikko Karttunen

Keyword(s):

Glutamic Acid ◽

Chain Length ◽

Chemical Structure ◽

Side Chain ◽

Side Chains ◽

Side Chain Length ◽

Polyelectrolyte Brushes ◽

Grafting Density ◽

The Difference ◽

Cellulose Surface

We used atomistic molecular dynamics (MD) simulations to study polyelectrolyte brushes based on anionic α,L-glutamic acid and α,L-aspartic acid grafted on cellulose in the presence of divalent CaCl2 salt at different concentrations. The motivation is to search for ways to control properties such as sorption capacity and the structural response of the brush to multivalent salts. For this detailed understanding of the role of side-chain length, the chemical structure and their interplay are required. It was found that in the case of glutamic acid oligomers, the longer side chains facilitate attractive interactions with the cellulose surface, which forces the grafted chains to lie down on the surface. The additional methylene group in the side chain enables side-chain rotation, enhancing this effect. On the other hand, the shorter and more restricted side chains of aspartic acid oligomers prevent attractive interactions to a large degree and push the grafted chains away from the surface. The difference in side-chain length also leads to differences in other properties of the brush in divalent salt solutions. At a low grafting density, the longer side chains of glutamic acid allow the adsorbed cations to be spatially distributed inside the brush resulting in a charge inversion. With an increase in grafting density, the difference in the total charge of the aspartic and glutamine brushes disappears, but new structural features appear. The longer sides allow for ion bridging between the grafted chains and the cellulose surface without a significant change in main-chain conformation. This leads to the brush structure being less sensitive to changes in salt concentration.

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