Special Features of Network Formation by Chain Crosslinking Copolymerization

1993 ◽  
Vol 58 (10) ◽  
pp. 2245-2265 ◽  
Author(s):  
Karel Dušek
Keyword(s):  
Network Formation ◽  
Double Bonds ◽  
Spatial Correlations ◽  
Phase Separations ◽  
Network Chain ◽  
Gel Phase ◽  
Chain Conformations ◽  
Theoretical Simulations ◽  
Steric Hindrances

Special features of free-radical crosslinking copolymerization and the structure of the resulting products have been reviewed. Characteristic is the effect of spatial correlations on the apparent reactivity of pendant double bonds. These correlation make the apparent reactivity in the course of copolymerization to increase (cyclization) and decrease (steric hindrances). At intermediate and higher concentrations of the crosslinker, compact structures are formed which are internally crosslinked. Only pendant double bonds in the peripheral layer are able to take part in polymerization reactions whereas the internal ones cannot react. The state of theoretical simulations of this structure growth is discussed with a special emphasis on the development of the kinetic (coagulation) network formation theories so that the above mentioned features may be taken into account. Also, the important role of the presence of a diluent during polymerization id discussed. It can result in a change of network chain conformations necessary for networks exhibiting volume phase transitions. Alternatively, it can induce liquid-gel phase separations resulting in inhomogeneous networks having a variety of morphologies.

Networks

2020 ◽  
pp. 534-562
Author(s):  
Matthew O. Jackson ◽  
Brian W. Rogers ◽  
Yves Zenou
Keyword(s):  
Social Networks ◽  
Social Network ◽  
Statistical Analysis ◽  
Labor Markets ◽  
Network Formation ◽  
Labor Market Outcomes ◽  
Negative Consequences ◽  
Social Scientists ◽  
Market Outcomes

What is the role of social networks in driving persistent differences between races and genders in education and labor market outcomes? What is the role of homophily in such differences? Why is such homophily seen even if it ends up with negative consequences in terms of labor markets? This chapter discusses social network analysis from the perspective of economics. The chapter is organized around the theme of externalities: the effects that one’s behavior has on others’ welfare. Externalities underlie the interdependencies that make networks interesting to social scientists. This chapter discusses network formation, as well as interactions between people’s behaviors within a given network, and the implications in a variety of settings. Finally, the chapter highlights some empirical challenges inherent in the statistical analysis of network-based data.

Key role of network formation in Rutting, fatigue and brittle performance of bitumen/PEG/MDI/SiO2 composites

2021 ◽  
Vol 296 ◽  
pp. 123739
Author(s):  
Tian Xia ◽  
Xiang Chen ◽  
Jianhui Xu ◽  
Anxin Zhang ◽  
Zhongli Wang ◽  
...  
Keyword(s):  
Network Formation

The thermodynamic properties of mixed phospholipid bilayers: a theoretical analysis

1984 ◽  
Vol 62 (8) ◽  
pp. 796-802 ◽  
Author(s):  
Maryse Mondat ◽  
A. Georgallas ◽  
D. A. Pink ◽  
M. J. Zuckermann
Keyword(s):  
Experimental Data ◽  
Thermodynamic Properties ◽  
Reasonable Agreement ◽  
Phospholipid Bilayers ◽  
Scanning Calorimetry ◽  
Phase Separations ◽  
Lipid Mixtures ◽  
Wide Range ◽  
Acyl Chains ◽  
Gel Phase

A theoretical model is presented with the intention of describing lateral phase separations in binary lipid mixtures in which the acyl chains of the components differ in their length. The model includes explicitly interactions between the acyl chains and between polar heads of the lipid molecules. Phase diagrams and thermodynamic properties of binary lipid mixtures were calculated using a wide range of interaction parameters. It is shown that the occurrence of immiscibility in the gel phase is related to the interactions between the polar heads of the lipid molecules. The calculated results for binary lipid mixtures are compared with the available experimental data. In particular, the calculated specific heat for dilauroyl phosphatidylcholine – distearoyl phosphatidylcholine is in reasonable agreement with experimental results obtained from differential scanning calorimetry measurements.

scholarly journals Role of packing density and spatial correlations in strongly scattering 3D systems

Optica ◽  
2018 ◽  
Vol 5 (9) ◽  
pp. 1037 ◽  
Author(s):  
Lorenzo Pattelli ◽  
Amos Egel ◽  
Uli Lemmer ◽  
Diederik S. Wiersma
Keyword(s):  
Packing Density ◽  
Spatial Correlations

Abstract 5: Neovascularization By Substance-p- Mobilized Epc And Msc In Vitro And In Vivo

2014 ◽  
Vol 115 (suppl_1) ◽  
Author(s):  
Hyun Sook Hong ◽  
Suna Kim ◽  
Youngsook Son
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Substance P ◽  
Network Formation ◽  
Skin Wound ◽  
Hematopoietic Stem ◽  
Vessel Structure

Bone marrow stem cells, especially, endothelial precursor cells (EPC), mesenchymal stem cells (MSC) or hematopoietic stem cell (HSC) are expected as reparative cells for the repair of a variety of tissue damages such as stroke and myocardial infarction, even though their role in the repair is not demonstrated. This report was investigated to find a role of Substance-p (SP) as a reparative agent in the tissue repair requiring EPC and MSC. In order to examine EPC (EPC SP ) and MSC (MSC SP ) mobilized by SP, we injected SP intravenously for consecutive 2 days and saline was injected as a vehicle. At 3 post injection, peripheral blood (PB) was collected.To get mesenchymal stem cells or endothelial progenitor cells, MNCs were incubated in MSCGM or EGM-2 respectively for 10 days. Functional characteristics of the EPC SP were proven by the capacity to form endothelial tubule network in the matrigel in vitro and in the matrigel plug assay in vivo. In contrast, MSC SP did not form a tube-like structure but formed a pellet-structure on matrigel. However, when both cells were premixed before the matrigel assay, much longer and branched tubular network was formed, in which a-SMA expressing MSC SP were decorating outside of the endothelial tube, especially enriched at the bifurcating point. MSC SP may contribute and reinforce elaborate vascular network formation in vivo by working as pericyte-like cells. Thus, the EPC SP and MSC SP were labeled with PKH green and PKH red respectively and their tubular network was examined. Well organized tubular network was formed, which was covered by PKH green labeled cells and was decorated in a punctate pattern by PKH red labeled cells. In order to investigate the role of EPC SP and MSC SP specifically in vivo, rabbit EPC SP and MSC SP were transplanted to full thickness skin wound. The vessel of EPC SP -transplanted groups was UEA-lectin+, which was not covered with a-SMA+ pericytes but EPC SP + MSC SP -transplanted groups showed, in part, a-SMA+ pericyte-encircled UEA-lectin+ vessels. This proved the specific role of MSC SP as pericytes. From these data, we have postulated that the collaboration of MSC and EPC is essential for normal vessel structure and furthermore, accelerated wound healing as ischemia diseases, which can be stimulated through by SP injection.

ENDOGENOUS SOCIAL DISTANCING AND CONTAINMENT POLICIES IN SOCIAL NETWORKS

2021 ◽  
Vol 257 ◽  
pp. 101-117
Author(s):  
Fabrizio Adriani ◽  
Dan Ladley
Keyword(s):  
Social Networks ◽  
Network Formation ◽  
Crowding Out ◽  
Policy Intervention ◽  
Negative Externalities ◽  
Formation Theory ◽  
Social Distancing ◽  
Face To Face ◽  
Underlying Network

Can smart containment policies crowd out private efforts at social distancing? We analyse this question from the perspective of network formation theory. We focus in particular on the role of externalities in social distancing choices. We also look at how these choices are affected by factors such as the agents’ risk perception, the speed of the policy intervention, the structure of the underlying network and the presence of strategic complementarities. We argue that crowding out is a problem when the probability that an outbreak may spread undetected is relatively high (either because testing is too infrequent or because tests are highly inaccurate). This is also the case where the choice of relaxing social distancing generates the largest negative externalities. Simulations on a real-world network suggest that crowding out is more likely to occur when, in the absence of interventions, face-to-face contacts are perceived to carry relatively high risk.

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