Investigating the Roles of Crystallizable and Glassy Switching Segments within Multiblock Copolymer Shape-Memory Materials

MRS Advances ◽  
2018 ◽  
Vol 3 (63) ◽  
pp. 3741-3749
Author(s):  
Wan Yan ◽  
Liang Fang ◽  
Ulrich Noechel ◽  
Oliver E. C. Gould ◽  
Marc Behl ◽  
...  
Keyword(s):  
Shape Memory ◽  
Tensile Tests ◽  
Multiblock Copolymers ◽  
Molecular Architecture ◽  
Memory Mechanism ◽  
Multiblock Copolymer ◽  
Relationship Of ◽  
Synergistic Relationship ◽  
Vapor Treatment ◽  
Insight Into

ABSTRACTThe variation of the molecular architecture of multiblock copolymers has enabled the introduction of functional behaviour and the control of key mechanical properties. In the current study, we explore the synergistic relationship of two structural components in a shape-memory material formed of a multiblock copolymer with crystallizable poly(ε-caprolactone) and crystallizable poly[oligo(3S-iso-butylmorpholine-2,5-dione)] segments (PCL-PIBMD). The thermal and structural properties of PCL-PIBMD films were compared with PCL-PU and PIBMD-PU, investigated by means of DSC, SAXS and WAXS measurements. The shape-memory properties were quantified by cyclic, thermomechanical tensile tests, where deformation strains up to 900% were applied for programming PCL-PIBMD films at 50 °C. Toluene vapor treatment experiments demonstrated that the temporary shape was fixed mainly by glassy PIBMD domains at strains lower than 600%, with the PCL contribution to fixation increasing to 42±2% at programming strains of 900%. This study into the shape-memory mechanism of PCL-PIBMD provides insight into the structure-function relation in multiblock copolymers with both crystallizable and glassy switching segments.

Study on Thermo-Mechanical Behaviors of Shape Memory Polymer

2009 ◽  
Vol 419-420 ◽  
pp. 497-500 ◽  
Author(s):  
Bo Zhou ◽  
Yan Ju Liu ◽  
Jin Song Leng ◽  
Tao Li
Keyword(s):  
Glass Transition ◽  
Shape Memory ◽  
Material Parameter ◽  
Shape Memory Polymer ◽  
Tensile Tests ◽  
Mechanical Analysis ◽  
New Material ◽  
Strain Relationship ◽  
Relationship Of ◽  
Parameter Function

Dynamic mechanical analysis (DMA) tests are conducted on styrene-based shape memory polymer(SMP) to investigate its glass transition behaviors. The tensile tests at various temperatures are operated to detect the stress-strain relationship of styrene-based SMP. The material elastic moduli and yielding limits at 25oC, 30oC, 40oC, and 50oC are determined according to the results of tensile test. A new material parameter function is supposed to express the glass transition behavior of styrene-based SMP. The shape memory thermo-mechanical cycle of styrene-based SMP is numerically simulated by Tobushi’s constitutive equation coupled with the new material parameter function. Numerical results show the new material parameter function can express the thermo-mechanical properties of styrene-based SMP effectively.

scholarly journals Molecular architecture and assembly of the yeast kinetochore MIND complex

2010 ◽  
Vol 190 (5) ◽  
pp. 823-834 ◽  
Author(s):  
Daniel P. Maskell ◽  
Xiao-Wen Hu ◽  
Martin R. Singleton
Keyword(s):  
Mitotic Spindle ◽  
Scattering Data ◽  
Molecular Architecture ◽  
Multiprotein Complex ◽  
Physical Relationship ◽  
X Ray ◽  
X Ray Scattering ◽  
The Mind ◽  
Relationship Of ◽  
Insight Into

The MIND multiprotein complex is a conserved, essential component of eukaryotic kinetochores and is a constituent of the tripartite KMN network that directly attaches the kinetochore to the mitotic spindle. The primary microtubule-binding complex in this network, NDC80, has been extensively characterized, but very little is known about the structure or function of the MIND complex. In this study, we present biochemical, hydrodynamic, electron microscopy, and small-angle x-ray scattering data that provide insight into the overall architecture and assembly of the MIND complex and the physical relationship of the complex with other components of the KMN network. We propose a model for the overall structure of the complex and provide data on the interactions with NDC80, Spc105p, and thus the mitotic spindle.

Skeletal elements of crinoid echinoderms: High-resolution structural and microanalytical results

1983 ◽  
Vol 41 ◽  
pp. 194-195
Author(s):  
D. F. Blake ◽  
L. F. Allard ◽  
D. R. Peacor
Keyword(s):  
High Resolution ◽  
Marine Invertebrates ◽  
Sea Urchins ◽  
Structural Features ◽  
Sea Stars ◽  
High Resolution Tem ◽  
Relationship Of ◽  
The Relationship ◽  
Insight Into

Echinodermata is a phylum of marine invertebrates which has been extant since Cambrian time (c.a. 500 m.y. before the present). Modern examples of echinoderms include sea urchins, sea stars, and sea lilies (crinoids). The endoskeletons of echinoderms are composed of plates or ossicles (Fig. 1) which are with few exceptions, porous, single crystals of high-magnesian calcite. Despite their single crystal nature, fracture surfaces do not exhibit the near-perfect {10.4} cleavage characteristic of inorganic calcite. This paradoxical mix of biogenic and inorganic features has prompted much recent work on echinoderm skeletal crystallography. Furthermore, fossil echinoderm hard parts comprise a volumetrically significant portion of some marine limestones sequences. The ultrastructural and microchemical characterization of modern skeletal material should lend insight into: 1). The nature of the biogenic processes involved, for example, the relationship of Mg heterogeneity to morphological and structural features in modern echinoderm material, and 2). The nature of the diagenetic changes undergone by their ancient, fossilized counterparts. In this study, high resolution TEM (HRTEM), high voltage TEM (HVTEM), and STEM microanalysis are used to characterize tha ultrastructural and microchemical composition of skeletal elements of the modern crinoid Neocrinus blakei.

On Metaphysics and the Political: A Polemics of Reading Baudelaire in the 1930s

2019 ◽  
Vol 58 (2) ◽  
pp. 249-259
Author(s):  
Joseph Acquisto
Keyword(s):  
Twentieth Century ◽  
Political Crisis ◽  
The Political ◽  
Modern Poetry ◽  
Progressive Politics ◽  
The World ◽  
Relationship Of ◽  
The Relationship ◽  
Insight Into

This essay examines a polemic between two Baudelaire critics of the 1930s, Jean Cassou and Benjamin Fondane, which centered on the relationship of poetry to progressive politics and metaphysics. I argue that a return to Baudelaire's poetry can yield insight into what seems like an impasse in Cassou and Fondane. Baudelaire provides the possibility of realigning metaphysics and politics so that poetry has the potential to become the space in which we can begin to think the two of them together, as opposed to seeing them in unresolvable tension. Or rather, the tension that Baudelaire animates between the two allows us a new way of thinking about the role of esthetics in moments of political crisis. We can in some ways see Baudelaire as responding, avant la lettre, to two of his early twentieth-century readers who correctly perceived his work as the space that breathes a new urgency into the questions of how modern poetry relates to the world from which it springs and in which it intervenes.

Phylogeny of actin and tubulin gene homologs in diverse eukaryotic species

2019 ◽  
Vol 79 (01S) ◽  
Author(s):  
Pawan Kumar Jayaswal ◽  
Asheesh Shanker ◽  
Nagendra Kumar Singh
Keyword(s):  
Evolutionary Relationship ◽  
Genomic Data ◽  
Gene Clusters ◽  
Species Trees ◽  
Model Species ◽  
Tubulin Gene ◽  
Tubulin Genes ◽  
Eukaryotic Species ◽  
Relationship Of ◽  
Insight Into

Actin and tubulin are cytoskeleton proteins, which are important components of the celland are conserved across species. Despite their crucial significance in cell motility and cell division the distribution and phylogeny of actin and tubulin genes across taxa is poorly understood. Here we used publicly available genomic data of 49 model species of plants, animals, fungi and Protista for further understanding the distribution of these genes among diverse eukaryotic species using rice as reference. The highest numbers of rice actin and tubulin gene homologs were present in plants followed by animals, fungi and Protista species, whereas ten actin and nine tubulin genes were conserved in all 49 species. Phylogenetic analysis of 19 actin and 18 tubulin genes clustered them into four major groups each. One each of the actin and tubulin gene clusters was conserved across eukaryotic species. Species trees based on the conserved actin and tubulin genes showed evolutionary relationship of 49 different taxa clustered into plants, animals, fungi and Protista. This study provides a phylogenetic insight into the evolution of actin and tubulin genes in diverse eukaryotic species.

scholarly journals Effect of Crystallographic Orientation and Grain Boundaries on Martensitic Transformation and Superelastic Response of Oligocrystalline Fe–Mn–Al–Ni Shape Memory Alloys

2021 ◽  
Author(s):  
A. Bauer ◽  
M. Vollmer ◽  
T. Niendorf
Keyword(s):  
Martensitic Transformation ◽  
Grain Boundary ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Grain Boundaries ◽  
Tensile Tests ◽  
Image Correlation ◽  
Stress Concentrations ◽  
Grain Orientations ◽  
High Degree

AbstractIn situ tensile tests employing digital image correlation were conducted to study the martensitic transformation of oligocrystalline Fe–Mn–Al–Ni shape memory alloys in depth. The influence of different grain orientations, i.e., near-〈001〉 and near-〈101〉, as well as the influence of different grain boundary misorientations are in focus of the present work. The results reveal that the reversibility of the martensite strongly depends on the type of martensitic evolving, i.e., twinned or detwinned. Furthermore, it is shown that grain boundaries lead to stress concentrations and, thus, to formation of unfavored martensite variants. Moreover, some martensite plates seem to penetrate the grain boundaries resulting in a high degree of irreversibility in this area. However, after a stable microstructural configuration is established in direct vicinity of the grain boundary, the transformation begins inside the neighboring grains eventually leading to a sequential transformation of all grains involved.

scholarly journals Assessing the synergistic relationship of mycorrhiza and bacteria for the degradation of spent engine oil in maize grown soil

2020 ◽  
Vol 44 (1) ◽  
Author(s):  
Ayokunle Samuel Bolaji ◽  
Mojeed Olaide Liasu ◽  
Abiodun Ayanfemi Ayandele ◽  
John Ayobami Amao
Keyword(s):  
Engine Oil ◽  
Spent Engine Oil ◽  
Relationship Of ◽  
Synergistic Relationship

scholarly journals Geo-Spatial Analysis of Population Density and Annual Income to Identify Large-Scale Socio-Demographic Disparities

2021 ◽  
Vol 10 (7) ◽  
pp. 432
Author(s):  
Nicolai Moos ◽  
Carsten Juergens ◽  
Andreas P. Redecker
Keyword(s):  
Population Density ◽  
Large Scale ◽  
Methodological Approach ◽  
Spatial Relationship ◽  
Postal Code ◽  
Annual Income ◽  
Choropleth Maps ◽  
Clustering Approach ◽  
Relationship Of ◽  
Insight Into

This paper describes a methodological approach that is able to analyse socio-demographic and -economic data in large-scale spatial detail. Based on the two variables, population density and annual income, one investigates the spatial relationship of these variables to identify locations of imbalance or disparities assisted by bivariate choropleth maps. The aim is to gain a deeper insight into spatial components of socioeconomic nexuses, such as the relationships between the two variables, especially for high-resolution spatial units. The used methodology is able to assist political decision-making, target group advertising in the field of geo-marketing and for the site searches of new shop locations, as well as further socioeconomic research and urban planning. The developed methodology was tested in a national case study in Germany and is easily transferrable to other countries with comparable datasets. The analysis was carried out utilising data about population density and average annual income linked to spatially referenced polygons of postal codes. These were disaggregated initially via a readapted three-class dasymetric mapping approach and allocated to large-scale city block polygons. Univariate and bivariate choropleth maps generated from the resulting datasets were then used to identify and compare spatial economic disparities for a study area in North Rhine-Westphalia (NRW), Germany. Subsequently, based on these variables, a multivariate clustering approach was conducted for a demonstration area in Dortmund. In the result, it was obvious that the spatially disaggregated data allow more detailed insight into spatial patterns of socioeconomic attributes than the coarser data related to postal code polygons.

scholarly journals Molecular architecture of the endocytic TPLATE complex

2021 ◽  
Vol 7 (9) ◽  
pp. eabe7999
Author(s):  
Klaas Yperman ◽  
Jie Wang ◽  
Dominique Eeckhout ◽  
Joanna Winkler ◽  
Lam Dai Vu ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Structural Approach ◽  
Eukaryotic Cells ◽  
Molecular Architecture ◽  
Membrane Proteome ◽  
Complex Assembly ◽  
Membrane Interaction ◽  
Structural Insight ◽  
Fresh Insight ◽  
Insight Into

Eukaryotic cells rely on endocytosis to regulate their plasma membrane proteome and lipidome. Most eukaryotic groups, except fungi and animals, have retained the evolutionary ancient TSET complex as an endocytic regulator. Unlike other coatomer complexes, structural insight into TSET is lacking. Here, we reveal the molecular architecture of plant TSET [TPLATE complex (TPC)] using an integrative structural approach. We identify crucial roles for specific TSET subunits in complex assembly and membrane interaction. Our data therefore generate fresh insight into the differences between the hexameric TSET in Dictyostelium and the octameric TPC in plants. Structural elucidation of this ancient adaptor complex represents the missing piece in the coatomer puzzle and vastly advances our functional as well as evolutionary insight into the process of endocytosis.

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