scholarly journals Learning from plant movements triggered by bulliform cells: the biomimetic cellular actuator

2020 ◽  
Vol 17 (169) ◽  
pp. 20200358
Author(s):  
Anja Mader ◽  
Max Langer ◽  
Jan Knippers ◽  
Olga Speck
Keyword(s):  
Individual Cell ◽  
Single Cells ◽  
Element Analysis ◽  
Functional Movement ◽  
Bulliform Cells ◽  
Entire Structure ◽  
Opening And Closing ◽  
Compliant Actuator ◽  
Technical Question

Within the framework of a biomimetic top-down approach, our study started with the technical question of the development of a hinge-free and compliant actuator inspired by plant movements. One meaningful biological concept generator was the opening and closing movements of the leaf halves of grasses. Functional morphological investigations were carried out on the selected model plant Sesleria nitida . The results formed the basis for further clarifying the functional movement principle with a particular focus on the role of turgor changes in bulliform cells on kinetic amplification. All findings gained from the investigations of the biological model were incorporated into a finite-element analysis, as a prerequisite for the development of a pneumatic cellular actuator. The first prototype consisted of a row of single cells positioned on a plate. The cells were designed in such a way that the entire structure bent when the pneumatic pressure applied to each individual cell was increased. The pneumatic cellular actuator thus has the potential for applications on an architectural scale. It has subsequently been integrated into the midrib of the facade shading system Flectofold in which the bending of its midrib controls the hoisting of its wings.

A Centennial History of the American Society of Mechanical Engineers: 1880-1980

1980 ◽  
Author(s):  
Bruce Sinclair
Keyword(s):  
New York ◽  
Progressive Era ◽  
Political System ◽  
City Government ◽  
American People ◽  
Engineering Problems ◽  
History Of ◽  
American Society ◽  
Technical Question

In 1980 the American Society of Mechanical Engineers celebrates the centenary of its founding. The occasion has provided an opportunity for the Society to look back and survey its accomplishments, its distinguished members, and its constant dialogue — among its members and with the American people — concerning the role of engineering in a technological society. The dynamic tensions within the ASME make a fascinating background to this centennial history. The central role of the Society’s headquarters in New York is examined the light of various movements for regional and professional sections within (and occasionally outside) the Society. The technical question of standards is shown to be a constant and creative problem for members — reflecting their attitudes towards their role in a political system often reluctant to enforce nation-wide standars in business and industry. From the Progressive Era, and its attempts to reform city government and check the power of private utilities, to the 1970s and its renewed concern with ecology and business ethnics, the Society has provided a microcosm of informed debate about technical engineering problems which — as this book makes clear — concerns us all.

Finite element analysis of hydrogen effects on superelastic NiTi shape memory alloys: Orthodontic application

2018 ◽  
Vol 29 (16) ◽  
pp. 3188-3198 ◽  
Author(s):  
Wissem Elkhal Letaief ◽  
Aroua Fathallah ◽  
Tarek Hassine ◽  
Fehmi Gamaoun
Keyword(s):  
Finite Element ◽  
Coupled Model ◽  
Element Model ◽  
Orthodontic Wires ◽  
Niti Wire ◽  
Element Analysis ◽  
Finite Element Software ◽  
Orthodontic Wire ◽  
Niti Shape Memory Alloys

Thanks to its greater flexibility and biocompatibility with human tissue, superelastic NiTi alloys have taken an important part in the market of orthodontic wires. However, wire fractures and superelasticity losses are notified after a few months from being fixed in the teeth. This behavior is due to the hydrogen presence in the oral cavity, which brittles the NiTi arch wire. In this article, a diffusion-mechanical coupled model is presented while considering the hydrogen influences on the NiTi superelasticity. The model is integrated in ABAQUS finite element software via a UMAT subroutine. Additionally, a finite element model of a deflected orthodontic NiTi wire within three teeth brackets is simulated in the presence of hydrogen. The numerical results demonstrate that the force applied to the tooth drops with respect to the increase in the hydrogen amount. This behavior is attributed to the expansion of the NiTi structure after absorbing hydrogen. In addition, it is shown that hydrogen induces a loss of superelasticity. Hence, it attenuates the role of the orthodontic wire on the correction tooth malposition.

scholarly journals Lattice-based microenvironmental uncertainty driven phenotypic decision-making: a comparison with Notch-Delta-Jagged signaling

2021 ◽  
Author(s):  
Aditi Ajith Pujar ◽  
Arnab Barua ◽  
Divyoj Singh ◽  
Ushasi Roy ◽  
Mohit Kumar Jolly ◽  
...  
Keyword(s):  
Decision Making ◽  
Variational Principle ◽  
Signaling Pathway ◽  
Biological System ◽  
Single Cells ◽  
Tissue Level ◽  
Spatiotemporal Patterns ◽  
Complex Environment ◽  
Agent Based

Phenotypic decision-making is a process of determining important phenotypes in accordance with the available microenvironmental information. Although phenotypic decision at the level of a single cell has been precisely studied, but the knowledge is still imperceptible at the multicellular level. How cells sense their environment and adapt? How single cells change their phenotype in a multicellular complex environment (without knowing the interactions among the cells), is still a rheotorical question. To unravel the fragmental story of multicellular decision-making, Least microEnvironmental Uncertainty Principle (LEUP) was refined and applied in this context. To address this set of questions, we use variational principle to grasp the role of sensitivity, build a LEUP driven agent-based model on a lattice which solely hinges on microenvironmental information and investigate the parallels in a well-known biological system, viz., Notch-Delta-Jagged signaling pathway. The analyses of this model led us to interesting spatiotemporal patterns in a population of cells, responsive to the sensitivity parameter and the radius of interaction. This resembles the tissue-level pattern of a population of cells interacting via Notch-Delta-Jagged signaling pathway in some parameter regimes.

scholarly journals Single-cell tumor-immune microenvironment of BRCA1/2 mutated high-grade serous ovarian cancer

2021 ◽  
Author(s):  
Inga-Maria Launonen ◽  
Nuppu Lyytikäinen ◽  
Julia Casado ◽  
Ella Anttila ◽  
Angéla Szabó ◽  
...  
Keyword(s):  
Tumor Microenvironment ◽  
Single Cell ◽  
Single Cells ◽  
High Grade ◽  
Prognostic Role ◽  
Immune Microenvironment ◽  
Proteomic Data ◽  
Tumor Immune Microenvironment ◽  
Cellular Phenotypes

Abstract The majority of high-grade serous ovarian cancers (HGSCs) are deficient in homologous recombination (HR) DNA repair, most commonly due to mutations or hypermethylation of the BRCA1/2 genes. We aimed to discover how BRCA1/2 mutations shape the cellular phenotypes and spatial interactions of the tumor microenvironment. Using a highly multiplex immunofluorescence and image analysis we generated spatial proteomic data for 21 markers in 124,623 single cells from 112 tumor cores originating from 31 tumors with BRCA1/2 mutation (BRCA1/2mut), and from 13 tumors without alterations in HR genes (HRwt). We identified a phenotypically distinct tumor microenvironment in the BRCA1/2mut tumors with evidence of increased immunosurveillance. Importantly, we found an opposing prognostic role of a proliferative tumor-cell phenotypic subpopulation in the HR-genotypes, which associated with enhanced spatial tumor-immune interactions by the CD8+ and CD4+T-cells in BRCA1/2mut tumors. The single-cell spatial landscapes indicate distinct patterns of spatial immunosurveillance with the premise to improve immunotherapeutic strategies and patient stratification in HGSC.

scholarly journals Embracing Hugh Blair. Rhetoric, Faith and Citizenship in 19th Century Mexico

2019 ◽  
Vol 56 ◽  
pp. 319-343
Author(s):  
Brian Connaughton
Keyword(s):  
19Th Century ◽  
Religious Faith ◽  
Atlantic History ◽  
Common People ◽  
Hugh Blair ◽  
Public Audience ◽  
Political Spectrum ◽  
Opening And Closing ◽  
The 19Th Century

This is a study of the key role of Hugh Blair, a Scottish Enlightened scholar and minister, in the understanding and teaching of rhetoric in a quarrelsome 19th-Century Mexico. His role as a master of multiple rhetorical forms, including legal prose, literary production and the sermon, emphasized effective communication to a broadening public audience in an age of expanding citizenship. First his Lectures on Rhetoric and Belles Lettres, and then several selections of his sermons, were introduced in Spanish to the Mexican public. Somewhat surprisingly, his works were highly celebrated and widely recommended, by persons on the whole political spectrum, with virtually no discussion of Blair’s political concerns or religious faith. His approach was useful, it was made clear, in a more fluid society aimed at modernization, but simultaneously contained a top-down view of life in society which seriously restricted sensitivity to the voice of common people. This article discusses his general acclaim and those limitations within the context of local and Atlantic history, taking into account the critical views of some of the numerous authors who have studied Blair’s work and his enormous influence during the 19th century. In the perspectives offered, his impact can be judged more critically in terms of an undoubtedly changing Mexican political culture, but one simultaneously opening and closing admission to effective citizenship.

Muscle development is independent of innervation during Drosophila embryogenesis

Development ◽  
1993 ◽  
Vol 119 (2) ◽  
pp. 533-543 ◽  
Author(s):  
K. Broadie ◽  
M. Bate
Keyword(s):  
Time Course ◽  
Muscle Development ◽  
Single Cells ◽  
Drosophila Embryo ◽  
Wild Type ◽  
Type Pattern ◽  
Motor Nerves ◽  
Embryonic Myogenesis ◽  
Peripheral Motor

We have examined the role of innervation in directing embryonic myogenesis, using a mutant (prospero), which delays the pioneering of peripheral motor nerves of the Drosophila embryo. In the absence of motor nerves, myoblasts fuse normally to form syncytial myotubes, myotubes form normal attachments to the epidermis, and a larval musculature comparable to the wild-type pattern is generated and maintained. Likewise, the twist-expressing myoblasts that prefigure the adult musculature segregate normally in the absence of motor nerves, migrate to their final embryonic positions and continue to express twist until the end of embryonic development. In the absence of motor nerves, myotubes uncouple at the correct developmental stage to form single cells. Subsequently, uninnervated myotubes develop the mature electrical and contractile properties of larval muscles with a time course indistinguishable from normally innervated myotubes. We conclude that innervation plays no role in the patterning, morphogenesis, maintenance or physiological development of the somatic muscles in the Drosophila embryo.

The role of greater tuberosity healing in reverse shoulder arthroplasty: a finite element analysis

2020 ◽  
Vol 29 (2) ◽  
pp. 347-354 ◽  
Author(s):  
Vani J. Sabesan ◽  
Diego J.L. Lima ◽  
Yang Yang ◽  
Matthew C. Stankard ◽  
Mauricio Drummond ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Shoulder Arthroplasty ◽  
Reverse Shoulder Arthroplasty ◽  
Element Analysis ◽  
Greater Tuberosity
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