47 research outputs found

    The Ethical Implications of Employing Socially Assitive Robots in the Aged-care Sector in Japan

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    Ground-breaking innovations in technology depict a promising future for humanity. In particular, the robotic industry is expected to solve many of our modern challenges especially with regard to the health sector. As expected, when introducing human-robot interactions in our daily lives, we need to renegotiate our human values in terms of autonomy, control and privacy. This paper aims to explore the ethical dilemmas occurring when employing socially assistive robots in the aged-care sector. It will also make recommendations for future ethical use of social robots. The cultural background is set in Japan, a leader in robotic development.“Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted under the conditions of the Creative Commons Attribution-Share Alike (CC BY-SA) license and that copies bear this notice and the full citation on the first page” Connection with SDG 9The Sustainable Development Goals number 9 refers to building resilient infrastructure, promote sustainable industrialization and foster innovation. These actions are highly dependent on technological innovations. In order to create long-term sustainable structures, we need to welcome advancements in our life but in the same time treat them carefully. This paper tackles one of the recent technological advancements in the field of robotics. Socially Assitive Robots have been designed to help children, people with disabilities and elders in a social, non-intrusive and positive way. In spite of this, ethical dilemmas which clash with the design of the robots are not often taken into account. That is why, the research is meant to fill in the gap and prove that an ethical sustainable goal can be met by responsible advancements in technology

    Exporting from a small landlocked economy : an assessment of firm-product-destination survival rates in the Lao PDR

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    This paper analyzes previously unreleased firm-level customs transaction data from the Lao PDR in order to assess the determinants of cohort survival among exporters. The authors find that export flows in value terms are dominated by the intensive margin, with large firms continuing to supply the same products to the same markets. On the extensive margin, new export spells for firms, products and firm-product-destination units are very small and short-lived, suggesting that although there is significant experimentation and discovery by firms, there is only limited capacity to stay in markets once an entry is made. Regression analyses of the factors that influence survival past the first year reveal that this is positively correlated with the initial dollar value (starting big makes a difference) and is helped by the firm's experience with the product and the destination, but hindered by a lack of focus. Agglomeration of exporters in the same destination with the same product is beneficial, an effect analogous to external economies of scale. The authors conclude by recommending that the focus of export promotion activity should be on helping existing exporters find and stay in new markets.Markets and Market Access,Microfinance,E-Business,Economic Theory&Research,Water and Industry

    XMM-Newton Observation of an X-ray Trail Between the Spiral Galaxy NGC6872 and the Central Elliptical NGC6876 in the Pavo Group

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    We present XMM-Newton observations of a trail of enhanced X-rayemission extending along the 8'.7 X 4' region between the spiral NGC6872 and the dominant elliptical NGC6876 in the Pavo Group,the first known X-ray trail associated with a spiral galaxy in a poor galaxy group and, with projected length of 90 kpc, one of the longest X-ray trails observed in any system. The X-ray surface brightness in the trail region is roughly constant beyond ~20 kpc of NGC6876 in the direction of NGC6872. The trail is hotter (~ 1 keV) than the undisturbed Pavo IGM (~0.5 keV) and has low metal abundances (0.2 Zsolar). The 0.5-2 keV luminosity of the trail, measured using a 67 X 90 kpc rectangular region, is 6.6 X 10^{40} erg/s. We compare the properties of gas in the trail to the spectral properties of gas in the spiral NGC6872 and in the elliptical NGC6876 to constrain its origin. We suggest that the X-ray trail is either IGM gas gravitationally focused into a Bondi-Hoyle wake, a thermal mixture of ~64% Pavo IGM gas with ~36% galaxy gas that has been removed from the spiral NGC6872 by turbulent viscous stripping, or both, due to the spiral's supersonic motion at angle xi ~ 40 degrees with respect to the plane of the sky, past the Pavo group center (NGC6876) through the densest region of the Pavo IGM. Assuming xi = 40 degrees and a filling factor eta in a cylindrical volume with radius 33 kpc and projected length 90 kpc, the mean electron density and total hot gas mass in the trail is 9.5 X 10^{-4}*eta^{-1/2} cm^{-3} and 1.1 X 10^{10}*eta^{1/2} Msolar, respectively.Comment: typos corrected in Eq. 7 & 8, figures and discussion unchanged, 39 pages, 11 postscript figures, submitted to Ap

    Colloquium: Mechanical formalisms for tissue dynamics

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    The understanding of morphogenesis in living organisms has been renewed by tremendous progressin experimental techniques that provide access to cell-scale, quantitative information both on theshapes of cells within tissues and on the genes being expressed. This information suggests that ourunderstanding of the respective contributions of gene expression and mechanics, and of their crucialentanglement, will soon leap forward. Biomechanics increasingly benefits from models, which assistthe design and interpretation of experiments, point out the main ingredients and assumptions, andultimately lead to predictions. The newly accessible local information thus calls for a reflectionon how to select suitable classes of mechanical models. We review both mechanical ingredientssuggested by the current knowledge of tissue behaviour, and modelling methods that can helpgenerate a rheological diagram or a constitutive equation. We distinguish cell scale ("intra-cell")and tissue scale ("inter-cell") contributions. We recall the mathematical framework developpedfor continuum materials and explain how to transform a constitutive equation into a set of partialdifferential equations amenable to numerical resolution. We show that when plastic behaviour isrelevant, the dissipation function formalism appears appropriate to generate constitutive equations;its variational nature facilitates numerical implementation, and we discuss adaptations needed in thecase of large deformations. The present article gathers theoretical methods that can readily enhancethe significance of the data to be extracted from recent or future high throughput biomechanicalexperiments.Comment: 33 pages, 20 figures. This version (26 Sept. 2015) contains a few corrections to the published version, all in Appendix D.2 devoted to large deformation

    Active wetting of epithelial tissues

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    Development, regeneration and cancer involve drastic transitions in tissue morphology. In analogy with the behavior of inert fluids, some of these transitions have been interpreted as wetting transitions. The validity and scope of this analogy are unclear, however, because the active cellular forces that drive tissue wetting have been neither measured nor theoretically accounted for. Here we show that the transition between 2D epithelial monolayers and 3D spheroidal aggregates can be understood as an active wetting transition whose physics differs fundamentally from that of passive wetting phenomena. By combining an active polar fluid model with measurements of physical forces as a function of tissue size, contractility, cell-cell and cell-substrate adhesion, and substrate stiffness, we show that the wetting transition results from the competition between traction forces and contractile intercellular stresses. This competition defines a new intrinsic lengthscale that gives rise to a critical size for the wetting transition in tissues, a striking feature that has no counterpart in classical wetting. Finally, we show that active shape fluctuations are dynamically amplified during tissue dewetting. Overall, we conclude that tissue spreading constitutes a prominent example of active wetting --- a novel physical scenario that may explain morphological transitions during tissue morphogenesis and tumor progression

    Aggregation kinetics of human mesenchymal stem cells under wave motion

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    Human mesenchymal stem cells (hMSCs) are a primary candidate in cell therapy and regenerative medicine to treat a wide range of diseases in clinical trials. Recent studies showed that hMSC have innate ability to self-assemble into three-dimensional (3D) aggregates that enhances their therapeutic functions with augmented multi-lineage differentiation potential, migration ability, secretion of anti-inflammatory and angiogenic factors, and resistance to ischemic conditions post-transplantation. To date, many laboratory methods have been developed for hMSC aggregation, including hanging drops, centrifugation with microfabricated surface, cell suspension on a low attachment surface, thermal lifting, and microfluidic technologies. However, these methods have limited scalability and/or poor control in aggregate size, and cannot meet the required production in clinical trials. The objective of current study is to investigate the conditions for the scalable production of hMSC aggregates in non-adherent plates under wave motion. The repeated back and forth wave motion induced by rocking provides mixing of bulk medium under low shear stress that facilitates cell-cell collisions and subsequent aggregation. Our results showed that aggregate size can be controlled by adjusting the combination of rocking angle (3˚, 6˚, and 9˚) and rocking speed (10, 15, and 20 rpm). To quantify the impact of fluid shear stress on aggregation kinetics, simulation of shear stress distribution by COMSOL Multiphysics® showed a time-dependent oscillatory function under different rocking condition. In addition, an inverse correlation between aggregate size and maximum shear stress was observed and that both can be regressed by a two-variable linear regression of rocking angle and rocking speed. In the regression, the coefficient of rocking angle is much higher than that of rocking speed, revealing that rocking angle has a more significant effect than rocking speed on both aggregate size and shear stress. In addition to fluid shear stress, the effects of cell binding molecules, the frequency of cell-cell collision, and the extension of cultivation time on aggregate size distribution were also investigated. Analysis of the therapeutic functional supported that hMSCs derived from engineered aggregates in the wave motion system have enhanced their therapeutic properties compared to those from monolayer culture

    Origine microscopique des propriétés rhéologiques et de surface des agrégats de cellules embryonnaires

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    Ces travaux de thèse portent sur l'étude expérimentale des propriétés physiques et de la biomécanique des agrégats cellulaires embryonnaires. Le but de cette thèse était d'une part de mieux comprendre l'origine biologique de la viscosité et de la tension de surface tissulaire, d'autre part d'étudier quantitativement en détail l'élasticité cellulaire par des nouvelles mesures de rhéologie en cisaillement. Un premier chapitre concerne les mesures de tension de surface tissulaire par la méthode de compression et de viscosité tissulaire par analyse de la cinétique de fusion de deux agrégats en faisant varier comme paramètre principal la contractilité cellulaire que certains suspectent comme étant la principale origine biologique de ces paramètres. Nous utilisons le formalisme du DITH (Haris, 1976: Differential Interfacial Tension Hypothesis) pour interpréter les données. Le deuxième chapitre concerne les mesures rhéologiques en cisaillement à l'aide d'un rhéomètre commercial plan-plan sur plusieurs centaines ou milliers d'agrégats cisaillés ensembles. Nous montrons que les cellules deviennent moins rigides pour une déformation minimale d'environ 4%, mais sur l'échelle de l'heure les cellules sont capables de se rigidifier à nouveau. Ces expériences sont analysées à l'aide d'un modèle de ressorts qui cassent sous contrainte puis se ressoudent à contrainte nulleThis thesis focuses on the experimental study of physical properties and biomechanics of embryonic cell aggregates. The aim of this thesis was on one hand to better understand the biological origin of tissue viscosity and tissue surface tension, and on the other hand to study quantitatively in detail cell elasticity by means of new rheological measurements in shear. A first chapter deals with measurements of tissue surface tension by tissue compression method and tissue viscosity by analysis of the fusion kinetics of two aggregates. We vary key parameters such as cell contractility that some people suspect to be the main biological origin of these parameters. We use the formalism of DITH (Haris, 1976: Differential Interfacial Tension Hypothesis) to interpret the data. The second chapter deals with rheological measurements in shear using a commercial plate-plate rheometer over several hundred of aggregates. We showed that cells become softer after a minimal deformation of 4% is reached, and can harden again on the timescale of hour. These experiences are analyzed using a model of springs that break under stress and then reattach at zero strai

    Origine microscopique des propriétés rhéologiques et de surface des agrégats de cellules embryonnaires

    No full text
    This thesis focuses on the experimental study of physical properties and biomechanics of embryonic cell aggregates. The aim of this thesis was on one hand to better understand the biological origin of tissue viscosity and tissue surface tension, and on the other hand to study quantitatively in detail cell elasticity by means of new rheological measurements in shear. A first chapter deals with measurements of tissue surface tension by tissue compression method and tissue viscosity by analysis of the fusion kinetics of two aggregates. We vary key parameters such as cell contractility that some people suspect to be the main biological origin of these parameters. We use the formalism of DITH (Haris, 1976: Differential Interfacial Tension Hypothesis) to interpret the data. The second chapter deals with rheological measurements in shear using a commercial plate-plate rheometer over several hundred of aggregates. We showed that cells become softer after a minimal deformation of 4% is reached, and can harden again on the timescale of hour. These experiences are analyzed using a model of springs that break under stress and then reattach at zero strain.Ces travaux de thèse portent sur l'étude expérimentale des propriétés physiques et de la biomécanique des agrégats cellulaires embryonnaires. Le but de cette thèse était d'une part de mieux comprendre l'origine biologique de la viscosité et de la tension de surface tissulaire, d'autre part d'étudier quantitativement en détail l'élasticité cellulaire par des nouvelles mesures de rhéologie en cisaillement. Un premier chapitre concerne les mesures de tension de surface tissulaire par la méthode de compression et de viscosité tissulaire par analyse de la cinétique de fusion de deux agrégats en faisant varier comme paramètre principal la contractilité cellulaire que certains suspectent comme étant la principale origine biologique de ces paramètres. Nous utilisons le formalisme du DITH (Haris, 1976: Differential Interfacial Tension Hypothesis) pour interpréter les données. Le deuxième chapitre concerne les mesures rhéologiques en cisaillement à l'aide d'un rhéomètre commercial plan-plan sur plusieurs centaines ou milliers d'agrégats cisaillés ensembles. Nous montrons que les cellules deviennent moins rigides pour une déformation minimale d'environ 4%, mais sur l'échelle de l'heure les cellules sont capables de se rigidifier à nouveau. Ces expériences sont analysées à l'aide d'un modèle de ressorts qui cassent sous contrainte puis se ressoudent à contrainte nulle
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