101 research outputs found
Synthetic extracellular matrix for controlled endothelial cell organization [Synthetische Extrazelluläre Matrix für die Organisation von Endothelzellen]
No full textThe thesis focuses on the development of a system that recapitulates the five criteria for a successful translatable synthetic extra cellular matrix (ECM): 1/ the control of the mechanical environment of the tissue, 2/ the controlled release of soluble signals, 3/ the transduction of the mechanical cues to the cells through immobilized signals, 4/ the identification of the appropriate cells for tissue regeneration and 5/ the adaptation of the materials into a therapeutic system.\ud
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In the first chapter, a literature review is presented. The components of the natural ECM are referenced and their roles in organogenesis are described. The different strategies that have been used for reproducing the synthetic ECM in vitro are referenced. Finally, the design choices followed for the elaboration of a new synthetic ECM are presented.\ud
The second chapter focuses on the design of a biocompatible hydrogels with versatile mechanical properties. The system is based on the naturally occurring polysaccharide agarose that forms under physiological conditions a reversible physical hydrogel. The carboxylation of the polysaccharide backbone allows the formation of hydrogels exhibiting different mechanical stiffness independent from the concentration.\ud
The third chapter proposes an easy solution for the reconstruction of the different mechanical properties of modified agarose by blending the different polysaccharides synthesized in the first chapter.\ud
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The fourth chapter extends the agarose modifications by incorporation of sulfate and phosphate moieties on the polymer backbone. These new polysaccharides are then used for the in vivo and in vitro controlled release of growth factors involved in angiogenesis.\ud
The fifth chapter proposes\ud
a strategy to immobilize “mechanotransduction” signals on the agarose backbone. This allows the mimicry of cell-ECM interactions and the transduction of mechanical information carried by the modified agarose hydrogels to the cells.\ud
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Furthermore, through the screening of different mechanical environments, the control of human endothelial cell organization into blood-vessel-like structure is presented.\ud
Since the removal of all immunogenic factors from a material is a key step for the successful translation of the system to the clinic, the sixth chapter describes a validated protocol for agarose sterilization and pyrogen removal
Biomaterials based strategies for engineering tumor microenvironment
No full textTissue engineering aims to gain mechanistic insights into human diseases and to develop new treatment protocols. Although 2-dimensional (2-D) flat petri dish culture and in vivo disease-based models are the industrial gold standards for understanding the underlying disease pathophysiology and for drug screening/testing, they are associated with certain limitations. While the 2-D cell culture systems fail to mimic in vivo signaling, animal-based disease models are associated with long incubation period, high cost, ethical constraints as well as depiction of human pathology in different species. Therefore, there has been a paradigm shift towards the development of 3-dimensional (3-D) based in vitro disease models. These models act as bridging gaps between the aforementioned conventional strategies thereby fastening clinical translation. In this regard, biomedical engineering plays a key role towards the development of tissue engineering based 3-D disease models. These models have demonstrated success in recapitulating human diseases in terms of in vivo morphology and signaling. This chapter will present examples of biomaterials-based 3-D engineered disease models with a focus on cancer
Methods for Purifying Polysaccharides and Pharmaceutical Compositions and Medical Devices Containing the Same
No full textMethods for removing endotoxin from naturally occurring materials, such as polysaccharides (e.g., agarose and/or carrageenan) are described herein. Polysaccharides that are substantially free of endotoxins and uses thereof are also described. The polysaccharide materials can be isolated from microorganisms, multicellular organisms, such as, algae, plants, seaweed, etc. The method involves the use of acidic and basic solutions to hydrolyze the lipid-polysaccharide bond in endotoxins. Cleaving the fatty acid from the polysaccharide reduces the water-solubility of the fatty acid and enables its removal with an organic solvent such as ethanol. The polysaccharide component can also undergo acidic or basic hydrolysis due to the weak glycosidic bond between the sugar rings
Template-free tuning of nanopores in carbonaceous polymers through ionothermal synthesis
No full textTemplate-free tuning of nanopores in highly porous carbonaceous polymers can be achieved through polymerization of dicyanobiphenyl at high temperatures in a ZnCl2 melt
AUTHOR CORRECTION - ERS International Congress 2019:highlights from Best Abstract awardees
No full textLorna E. Latimer, Marieke Duiverman, Mahmoud I. Abdel-Aziz, Gulser Caliskan, Sara M. Mensink-Bout, Alberto Mendoza-Valderrey, Aurelien Justet, Junichi Omura, Karthi Srikanthan, Jana De Brandt. Breathe 2019; 15: e143–e149. This article from the December 2019 issue of Breathe was published with an error in the name of one of the authors. The corrected author list is shown above. The article has been corrected and republished online.</p
Oxygen-releasing coatings for improved tissue preservation
No full textCurrent organ transplantation protocols require the rapid transport of freshly isolated donor tissue to the recipient patient at the site where the procedure is to be conducted. During transport, the tissue graft can quickly deteriorate as a result of oxygen starvation. In this study, we report the fabrication of oxygen-releasing coatings for improved tissue preservation. The coatings were prepared via the encapsulation of calcium peroxide or urea peroxide microparticles between layers of octadiene plasma polymer films. By varying the thickness of the plasma polymer coating and type of peroxide, formulations were obtained that generate oxygen upon contact with aqueous solutions, while at the same time limiting the amount of toxic reactive oxygen species produced. The optimized coatings were tested under hypoxic conditions using the MIN6 β-cell line, which resulted in a 3-fold increase in the viability of cultured cells. These thin oxygen-releasing coatings can be deposited on a wide range of surfaces, creating a platform for oxygen delivery with the potential to extend the viability of transported tissues and increase the time frame available for graft transport
Synthetische Extrazelluläre Matrix für die Organisation von Endothelzellen
No full textThe thesis focuses on the development of a system that recapitulates the five criteria for a successful translatable synthetic extra cellular matrix (ECM): 1/ the control of the mechanical environment of the tissue, 2/ the controlled release of soluble signals, 3/ the transduction of the mechanical cues to the cells through immobilized signals, 4/ the identification of the appropriate cells for tissue regeneration and 5/ the adaptation of the materials into a therapeutic system.
In the first chapter, a literature review is presented. The components of the natural ECM are referenced and their roles in organogenesis are described. The different strategies that have been used for reproducing the synthetic ECM in vitro are referenced. Finally, the design choices followed for the elaboration of a new synthetic ECM are presented.
The second chapter focuses on the design of a biocompatible hydrogels with versatile mechanical properties. The system is based on the naturally occurring polysaccharide agarose that forms under physiological conditions a reversible physical hydrogel. The carboxylation of the polysaccharide backbone allows the formation of hydrogels exhibiting different mechanical stiffness independent from the concentration.
The third chapter proposes an easy solution for the reconstruction of the different mechanical properties of modified agarose by blending the different polysaccharides synthesized in the first chapter.
The fourth chapter extends the agarose modifications by incorporation of sulfate and phosphate moieties on the polymer backbone. These new polysaccharides are then used for the in vivo and in vitro controlled release of growth factors involved in angiogenesis.
The fifth chapter proposes a strategy to immobilize “mechanotransduction” signals on the agarose backbone. This allows the mimicry of cell-ECM interactions and the transduction of mechanical information carried by the modified agarose hydrogels to the cells.
Furthermore, through the screening of different mechanical environments, the control of human endothelial cell organization into blood-vessel-like structure is presented.
Since the removal of all immunogenic factors from a material is a key step for the successful translation of the system to the clinic, the sixth chapter describes a validated protocol for agarose sterilization and pyrogen removal.
Die vorgelegte Arbeit präsentiert die Entwicklung eines neuen Systems für die Durchführung einer dreidimensionalen Zellkultur einer künstlichen ECM. Das System basiert auf fünf Kriterien, die für die Generierung einer ECM in vitro eine besondere Rolle einnehmen. 1/ die Modulierung der mechanischen Eigenschaften des Gewebes, 2/ die gezielte Abgabe von Proteinen und Botenstoffen zu definierten Zeitpunkten, 3/ die Bereitstellung von immobilisierten bioloschen Signalen, um die Übertragung der mechanischen Reize in die Zellen zu gewährleisten, 4/ die Entwicklung von zellspezifischer ECM, um eine optimale Gewebekonstruktion zu erhalten und 5/ die Anpassung des ganzen Systems auf klinische Fragestellungen.
Im ersten Kapitel wird ein Überblick über die vorhandene Literatur gegeben. Die Komponenten der natürlichen ECM sind aufgeführt und deren Aufgaben in der Bildung von Organen werden erklärt. Des Weiteren werden die verschiedenen und schon vorhandenen Ansätze zur Reproduktion synthetischer ECM in vitro erläutert. Abschließend wird die für diese Arbeit ausgesuchte Methode diskutiert.
Das zweite Kapitel handelt von der Entwicklung eines biokompatiblen Hydrogels mit vielseitigen mechanischen Eigenschaften. Das System basiert auf natürlich vorkommenden Polysacchariden (Agarose). Dieses Material bildet unter bestimmten physikalischen Bedingungen ein Hydrogel. Durch chemische Modifizierung werden die mechanischen Eigenschaften kontrolliert, um dadurch die natürliche Umgebung von Zellen zu simulieren.
Das dritte Kapitel beschreibt die verschiedenen mechanischen Eigenschaften modifizierter Agarose (Synthese siehe 2. Kapitel) die durch Mischung mehrerer Polysaccharide miteinander entstehen. Außerdem wird auch die Konsistenz und Mikrostruktur von natürlich vorkommender und modifizierter Agarose diskutiert.
Im vierten Kapitel wird die Modifizierung von Agarose durch den Einbau von Sulfat- und Phosphateinheiten in das Polymerrückgrat tiefer gehend analysiert. Die Abgabe von Wachstumsfaktoren während der Bildung von Blutgefäßen wird in vivo und in vitro untersucht.
Das fünfte Kapitel schlägt eine Strategie vor, mit der biologische Signale im Polymerrückgrat immobilisiert werden können. Diese Signale sind für die Wechselwirkung zwischen Zellen und ECM verantwortlich. Des Weiteren werden aus diesen Polysacchariden dreidimensionale Gerüste designt in denen Endothelzellen in Kultur wachsen können. Durch den Einsatz dieser besonderen Umgebung konnten sich Blutgefäßstrukturen bilden.
Das sechste Kapitel beschreibt ein Protokoll, mit dessen Hilfe Agarose sterilisiert werden kann, um einen Einsatz dieses Materials für klinische Studien garantieren zu können. Mikrobielle und chemische Kontaminationen wurden charakterisiert und Pyrogen konnte aus der Agarose entfernt werden.
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Parametrized cosmological mass maps dataset
No full textParametrized cosmological mass maps dataset
This dataset consists of the non-tomographic training and testing set without noise and intrinsic alignments.
It was introduced in the following paper
Fluri, Janis, et al. "Cosmological constraints with deep learning from KiDS-450 weak lensing maps." Physical Review D 100.6 (2019): 063514.
Furthermore, this dataset is released with the following paper:
Perraudin, Nathanaël, et al. "Emulation of cosmological mass maps with conditional generative adversarial networks." arXiv preprint arXiv:2004.08139 (2020).
Code related to this dataset can be found in https://renkulab.io/projects/nathanael.perraudin/darkmattergan
Description
The simulation grid consists of different cosmologies assuming a flat LambdaCDM universe.
Each of these 57 configurations was run with different values of Omega_m and sigma_8, resulting in the following parameter grid.| Omega_m, sigma_8
0.101, 1.304
0.102, 1.125
0.103, 0.947
0.120, 1.178
0.123, 1.006
0.127, 0.836
0.137, 1.230
0.142, 1.063
0.148, 0.900
0.154, 1.281
0.156, 0.741
0.161, 1.119
0.169, 0.961
0.171, 1.331
0.178, 0.807
0.179, 1.173
0.188, 1.019
0.189, 0.659
0.196, 1.225
0.199, 0.870
0.207, 1.075
0.212, 0.727
0.219, 0.930
0.225, 1.129
0.227, 0.591
0.233, 0.791
0.238, 0.988
0.250, 0.658
0.254, 0.852
0.257, 1.043
0.269, 0.534
0.271, 0.723
0.273, 0.910
0.291, 0.601
0.291, 0.783
0.292, 0.966
0.311, 0.842
0.312, 0.664
0.314, 0.487
0.330, 0.898
0.332, 0.724
0.335, 0.552
0.352, 0.782
0.356, 0.614
0.370, 0.838
0.376, 0.673
0.382, 0.510
0.395, 0.730
0.402, 0.570
0.413, 0.784
0.421, 0.628
0.431, 0.475
0.440, 0.683
0.450, 0.533
0.458, 0.737
0.469, 0.589
0.487, 0.643
Each zip file in the dataset corresponds to 1 of these combinations and contains 12 files containing 1000 images.
The source galaxy redshift distribution corresponding to these maps is the full, non-tomographic redshift distribution n(z) from Fluri et. al.
The projected matter distribution was pixelised into images of size 128px x 128px, which correspond to 5deg x 5deg of the sky.
Eventually, the resulting dataset consists of 57 sets of 12'000 sky convergence maps for a total of samples.
Citations
If you use this dataset, please cite:
@article{perraudin2020emulation,
title={Emulation of cosmological mass maps with conditional generative adversarial networks},
author={Perraudin, Nathana{\"e}l and Marcon, Sandro and Lucchi, Aurelien and Kacprzak, Tomasz},
journal={arXiv preprint arXiv:2004.08139},
year={2020}
}
and
@article{fluri2019cosmological,
title={Cosmological constraints with deep learning from KiDS-450 weak lensing maps},
author={Fluri, Janis and Kacprzak, Tomasz and Lucchi, Aurelien and Refregier, Alexandre and Amara, Adam and Hofmann, Thomas and Schneider, Aurel},
journal={Physical Review D},
volume={100},
number={6},
pages={063514},
year={2019},
publisher={APS}
Not all feminists are worth supporting
No full textThe following thoughts came to me after a recent Melbourne Free University lecture on the Future of Feminism. The insightful presentation given by Melbourne Feminist Collective’s Neda Monshat and Alexia Staker led to a fascinating discussion in the second part of the event. Two points in particular finally convinced me to write about feminism and its future, if it is to have one. My first concern is related to the presenters’ wish for all feminists to forget their differences and stand in sol..
Not all feminists are worth supporting
No full textThe following thoughts came to me after a recent Melbourne Free University lecture on the Future of Feminism. The insightful presentation given by Melbourne Feminist Collective’s Neda Monshat and Alexia Staker led to a fascinating discussion in the second part of the event. Two points in particular finally convinced me to write about feminism and its future, if it is to have one. My first concern is related to the presenters’ wish for all feminists to forget their differences and stand in sol..
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