Impact of hydrogel stiffness on differentiation of human adipose-derived stem cell microspheroids

Hydrogels represent an attractive material platform for realization of three-dimensional (3D) tissue-engineered constructs, as they have tunable mechanical properties, are compatible with different types of cells, and resemble elements found in natural extracellular matrices. So far, numerous hydrogel-cartilage/bone tissue engineering (TE)-related studies were performed by utilizing a single cell encapsulation approach. Although multicellular spheroid cultures exhibit advantageous properties for cartilage or bone TE, the chondrogenic or osteogenic differentiation potential of stem cell microspheroids within hydrogels has not been investigated much. This study explores, for the first time, how stiffness of gelatin-based hydrogels (having a storage modulus of 538, 3584, or 7263 Pa) affects proliferation and differentiation of microspheroids formed from telomerase-immortalized human adipose-derived stem cells (hASC/hTERT). Confocal microscopy indicates that all tested hydrogels supported cell viability during their 3- to 5-week culture period in the control, chondrogenic, or osteogenic medium. Although in the softer hydrogels cells from neighboring microspheroids started outgrowing and interconnecting within a few days, their protrusion was slower or limited in stiffer hydrogels or those cultured in chondrogenic medium, respectively. High expressions of chondrogenic markers (SOX9, ACAN, COL2A1), detected in all tested hydrogels, proved that the chondrogenic differentiation of hASC/hTERT microspheroids was very successful, especially in the two softer hydrogels, where superior cartilage-specific properties were confirmed by Alcian blue staining. These chondrogenically induced samples also expressed COL10A1, a marker of chondrocyte hypertrophy. Interestingly, the hydrogel itself (with no differentiation medium) showed a slight chondrogenic induction. Regardless of the hydrogel stiffness, in the samples stimulated with osteogenic medium, the expression of selected markers RUNX2, BGLAP, ALPL, and COL1A1 was not conclusive. Nevertheless, the von Kossa staining confirmed the presence of calcium deposits in osteogenically stimulated samples in the two softer hydrogels, suggesting that these also favor osteogenesis. This observation was also confirmed by Alizarin red quantification assay, with which higher amounts of calcium were detected in the osteogenically induced hydrogels than in their controls. The presented data indicate that the encapsulation of adipose-derived stem cell microspheroids in gelatin-based hydrogels show promising potential for future applications in cartilage or bone TE. Impact Statement Osteochondral defects represent one of the leading causes of disability in the world. Although numerous tissue engineering (TE) approaches have shown success in cartilage and bone tissue regeneration, achieving native-like characteristics of these tissues remains challenging. This study demonstrates that in the presence of a corresponding differentiation medium, gelatin-based hydrogels support moderate osteogenic and excellent chondrogenic differentiation of photo-encapsulated human adipose-derived stem cell microspheroids, the extent of which depends on hydrogel stiffness. Because photosensitive hydrogels are a convenient material platform for creating stiffness gradients in three dimensions, the presented microspheroid-hydrogel encapsulation strategy holds promise for future strategies of cartilage or bone TE

Elective Modernism and the Politics of (Bio) Ethical Expertise

In this essay I consider whether the political perspective of third wave science studies – ‘elective modernism’ – offers a suitable framework for understanding the policy-making contributions that (bio)ethical experts might make. The question arises as a consequence of the fact that I have taken inspiration from the third wave in order to develop an account of (bio)ethical expertise. I offer a précis of this work and a brief summary of elective modernism before considering their relation. The view I set out suggests that elective modernism is a political philosophy and that although its use in relation to the use of scientific expertise in political and policy-making process has implications for the role of (bio)ethical expertise it does not, in the final analysis, provide an account that is appropriate for this latter form of specialist expertise. Nevertheless, it is an informative perspective, and one that can help us make sense of the political uses of (bio)ethical expertise

Interactive 3D simulation for fluid–structure interactions using dual coupled GPUs

The scope of this work involves the integration of high-speed parallel computation with interactive, 3D visualization of the lattice-Boltzmann-based immersed boundary method for fluid–structure interaction. An NVIDIA Tesla K40c is used for the computations, while an NVIDIA Quadro K5000 is used for 3D vector field visualization. The simulation can be paused at any time step so that the vector field can be explored. The density and placement of streamlines and glyphs are adjustable by the user, while panning and zooming is controlled by the mouse. The simulation can then be resumed. Unlike most scientific applications in computational fluid dynamics where visualization is performed after the computations, our software allows for real-time visualizations of the flow fields while the computations take place. To the best of our knowledge, such a tool on GPUs for FSI does not exist. Our software can facilitate debugging, enable observation of detailed local fields of flow and deformation while computing, and expedite identification of ‘correct’ parameter combinations in parametric studies for new phenomenon. Therefore, our software is expected to shorten the ‘time to solution’ process and expedite the scientific discoveries via scientific computing

Hymen reconstruction as pragmatic empowerment? Results of a qualitative study from Tunisia

Hymen reconstruction surgery (HR), while ethically controversial, is now available in many countries. Little clinical evidence and hardly any surgical standards support the intervention. Nearly as scarce is social science research exploring women's motivations for the intervention, and health care professionals' justifications for its provision. In order to better understand decision-making processes, we conducted semi-structured interviews in metropolitan Tunis, in 2009, with six women seeking the procedure, four friends who supported such women, four physicians who perform the operation, and one midwife. Health care professionals and patient companions expressed moral ambivalence about HR: although they could comprehend the individual situation of the women, they expressed concern that availability of the procedure might further entrench the patriarchal norms that compel the motivation for seeking HR in the first place. Some women seeking HR shared this concern, but felt it was not outweighed by their personal aims, which were to marry and become mothers, or to overcome past violent sexual experiences. The women felt HR to be uniquely helpful in achieving these aims; all made pragmatic decisions about their bodies in a social environment dominated by patriarchal norms. The link between HR and pervasive gender injustice, including the credible threat of serious social and physical harm to women perceived to have failed to uphold the norm of virginity before marriage, raises questions about health care professionals' responsibility while facing requests for HR. Meaningful regulatory guidance must acknowledge that these genuine harms are at stake; it must do so, however, without resorting to moral double standards. We recommend a reframing of HR as a temporary resource for some women making pragmatic choices in a context of structural gender injustice. We reconfirm the importance of factual sexual and reproductive education, most importantly to counter distorted beliefs that conflate an “intact hymen” with virginity

‘To fill yourself with goodness’: revolutionary self-making in Bolivarian Venezuela

This article explores how utopian visions are articulated by chavista activists in Venezuela through the practice of 'revolutionary self-making'. Drawing on ethnographic fieldwork conducted in the city of Valencia between 2008 and 2012, it aims to demonstrate how close attention to the formation of new moral and spiritual selves is an integral part of the way that chavistas enact and experience political protagonism. In doing so, the article seeks to provide a ground level view of utopian visions as they are manifested discursively and practically in everyday life

Questions of Identity, Migrations and Transculturality: The Case of the Poet Cvetka Lipuš

Cvetka Lipuš is an internationally acclaimed multi-award-winning poet born in the Carinthia region in Austria. After graduating from university in Austria, she moved to the United States. After more than a decade of living across the Atlantic, she returned and settled in Salzburg. She has published seven poetry collections to date, and is one of the most important ambassadors of Slovenian culture abroad. She writes her poetry only in her mother tongue, i.e. Slovene, while she has also studied and worked in German and English. In this paper, we examine how her migrations and the three cultures are reflected in her life and work.Pesnica Cvetka Lipuš je mednarodno uveljavljena in večkrat nagrajena pesnica, rojena na avstrijskem Koroškem. Po študiju v Avstriji je odšla v Združene države Amerike, nato pa se je po več kot desetletju bivanja čez lužo vrnila in se ustalila v Salzburgu. Doslej je izdala sedem pesniških zbirk in je ena izmed najpomembnejših ambasadork slovenske kulture v tujini. Svoje pesniške misli preliva na papir izključno v slovenščini, svojem prvem jeziku, medtem ko sta nemščina in angleščina jezika njene izobrazbe in poklicnega življenja. V prispevku se avtorji sprašujejo, kako se migracije in trije kulturni krogi, ki jo spremljajo, odražajo v njenem življenju in delu