2,771 research outputs found

    A radial mode ultrasonic horn for the inactivation of <i>Escherichia coli</i> K12

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    Tuned cylindrical radial mode ultrasonic horns offer advantages over ultrasonic probes in the design of flow-through devices for bacterial inactivation. This study presents a comparison of the effectiveness of a radial horn and probe in the inactivation of Escherichia coli K12. The radial horn is designed using finite element analysis and the predicted modal parameters are validated using experimental modal analysis. A validated finite element model of the probe is also presented. Visual studies of the cavitation fields produced by the radial horn and probe are carried out using luminol and also backlighting to demonstrate the advantages of radial horns in producing a more focused cavitation field with widely dispersed streamers. Microbiological studies show that, for the same power density, better inactivation of E. coli K12 is achieved using the radial horn and, also, the radial horn offers greater achievable power density resulting in further improvements in bacterial inactivation. The radial horn is shown to be more effective than the probe device and offers opportunities to design in-line flow-through devices for processing applications

    Boundary value problems of elasticity theory for plane domains with one-dimensional elastic reinforcements

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    This article is a translation of an article published in Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No 1, pp 103-114 Jan-Feb 1991.Many authors have examined problems related to the load transmission from an elastic rod to an elastic plane. It was assumed in the majority of investigationa that the stringer is a thin rectilinear rod transmitting only longitudinal forces while the rod contact with the plane is realized along a line. different modifications of sheet contact with a rectilinear tensile stringer considered as an inner stringer of finite length or as an infinite edge stringer were analyzed in [1, 2]. Problems about the reinforcement of holes in a plate by a thin rod of constant section that possesses bending and longitudinal stiffnesses were solved in [3]. The eccentricity of the connection between the shell middle surface and the rod was taken into account in [4] in a study of shells reinforced by thin curvilinear rods. Other models of the one-dimensional element connected to an elastic medium without taking account of its bending stiffness were analyzed in [5, 6]. Solutions of a number of problems with circular reinforcing elements are obtained in [7]. An isotropic finite or infinite, linearly elastic plate reinforced along part or all of the boundary and along certain internal lines by elastic curvilinear rods possessing variable longitudinal and bending stiffnesses, variable curvature and thickness, the eccentricity of the connection to the plate and with an arbitrary transverse section shape symmetric relative to the plate middle surface are studied in this paper. Boundary conditions on the line of plate contact with the inner or edge elastic rods are obtained for the reinforcement models generalizing [1, 2] by using the theory of elastic rods in the case of a plane state of stress. Existence and uniqueness theorems are proved for appropriate boundary value problems; the singularity of the stresses at angles and tips of the rods are proved. The relationships obtained carry over completely to the plane strain problem for an elastic cylinder reinforced by homogeneous cylindrical shells along the generator. Some of the results described here are represented in [8]

    On the cohomology of some exceptional symmetric spaces

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    This is a survey on the construction of a canonical or "octonionic K\"ahler" 8-form, representing one of the generators of the cohomology of the four Cayley-Rosenfeld projective planes. The construction, in terms of the associated even Clifford structures, draws a parallel with that of the quaternion K\"ahler 4-form. We point out how these notions allow to describe the primitive Betti numbers with respect to different even Clifford structures, on most of the exceptional symmetric spaces of compact type.Comment: 12 pages. Proc. INdAM Workshop "New Perspectives in Differential Geometry" held in Rome, Nov. 2015, to appear in Springer-INdAM Serie

    Boundary Crossing in School Governing Bodies: Perspectives from the Business Community

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    Policy changes to school governance have led to Governing Bodies (GBs) increasingly appointing skilled professionals from the business community. Research into these GBs views governors from business as a threat to lay governors and the stakeholder model (Young, 2017). Whilst there has been exploration of the contributions of business governors, the ways in which business volunteers develop into their new roles as business governors have not been captured. This paper is drawn from an evaluation of Lloyds Banking Group’s (LBG) school governance programme where 18 LBG employees were interviewed throughout the first year in their governor roles. Adapting Young’s (2017) categorisation of knowledge as ‘managerial’, ‘educational’ and ‘lay’, this paper articulates how LBG governors acquired ‘educational’ and ‘lay’ knowledge to transform their practices and how this was underpinned by ‘authenticity’ associated with the stakeholder model (Connolly, 2017). The paper presents perspectives from other GB stakeholders which suggest that the transformation of the LBG governors’ practice impacted upon GBs, with them crossing boundaries between landscapes of practice (Wenger-Trayner and Wenger-Trayner, 2014). The implications are that, within the context of performativity, the wider business sector has a role to play in school governance and understanding governor professional development is key to this

    Mothers' experiences of wellbeing and coping while living with rheumatoid arthritis : a qualitative study

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    Background: Rheumatoid arthritis (RA) can result in difficulties for mothers when undertaking daily care activities and increased psychological distress. However, few studies have examined how women with RA subjectively experience coping and wellbeing as part of their motherhood. Methods: Twenty mothers with a diagnosis of RA and a dependent child (18 years or younger) who were living in Australia took part in a semi-structured interview between June and November 2017. Purposive sampling was undertaken to include participants across degree of current RA severity, number and age of children, and having received a diagnosis before or after a first child to take account of variability across these experiences. A qualitative thematic analysis was conducted on the interview transcripts. Results: The following themes were identified: ‘Burden and complexity in the mothering role’, ‘Losing control: Women’s experiences of distress’, and ‘Adjusting and letting go: Women’s experiences of wellbeing’. Experiences of distress, including feelings of failure, were associated with accounts of a loss of control over mothering practices among women, regardless of child age. In contrast, accounts of adjusting mothering practices and relinquishing control were associated with reports of enhanced wellbeing. In addition, some mothers reported greater ease due to increased independence of older children. The absence of social support exacerbated burden and distress in the women’s accounts, while the availability of support alleviated burden and was associated with reports of wellbeing. Conclusion: Health professionals and services can provide support to mothers with RA by addressing feelings of failure, acknowledging strategies of adjustment and letting go, and encouraging access to social support

    Subcellular mRNA localisation at a glance.

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    mRNA localisation coupled to translational regulation provides an important means of dictating when and where proteins function in a variety of model systems. This mechanism is particularly relevant in polarised or migrating cells. Although many of the models for how this is achieved were first proposed over 20 years ago, some of the molecular details are still poorly understood. Nevertheless, advanced imaging, biochemical and computational approaches have started to shed light on the cis-acting localisation signals and trans-acting factors that dictate the final destination of localised transcripts. In this Cell Science at a Glance article and accompanying poster, we provide an overview of mRNA localisation, from transcription to degradation, focusing on the microtubule-dependent active transport and anchoring mechanism, which we will use to explain the general paradigm. However, it is clear that there are diverse ways in which mRNAs become localised and target protein expression, and we highlight some of the similarities and differences between these mechanisms.This work was supported by a Wellcome Trust Senior Research Fellowship to I.D. supporting R.M.P. [grant number: 096144], a studentship from the Wellcome Trust to A.D. [grant number: 097304], the University of Cambridge, ISSF to T.T.W. [grant number 097814].This is the final version of the article. It first appeared from the Company of Biologists via http://dx.doi.org/10.1242/jcs.11427

    Biogenesis of phagolysosomes proceeds through a sequential series of interactions with the endocytic apparatus

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    We have examined the modifications occurring during the transformation of phagosomes into phagolysosomes in J-774 macrophages. The use of low density latex beads as markers of phagosomes (latex bead compartments, LBC) allowed the isolation of these organelles by flotation on a simple sucrose gradient. Two-dimensional gel electrophoresis, immunocytochemistry, and biochemical assays have been used to characterize the composition of LBC at different time points after their formation, as well as their interactions with the organelles of the endocytic pathway. Our results show that LBC acquire and lose various markers during their transformation into phagolysosomes. Among these are members of the rab family of small GTPases as well as proteins of the lamp family. The transfer to the LBC of lamp 2, a membrane protein associated with late endocytic structures, was shown to be microtubule dependent. Videomicroscopy showed that newly formed phagosomes were involved in rapid multiple contacts with late components of the endocytic pathway. Collectively, these observations suggest that phagolysosome formation is a highly dynamic process that involves the gradual and regulated acquisition of markers from endocytic organelles

    SAI: A sensible artificial intelligence that plays with handicap and targets high scores in 9x9 Go

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    We develop a new framework for the game of Go to target a high score, and thus a perfect play. We integrate this framework into the Monte Carlo tree search - policy iteration learning pipeline introduced by Google DeepMind with AlphaGo. Training on 9×9 Go produces a superhuman Go player, thus proving that this framework is stable and robust. We show that this player can be used to effectively play with both positional and score handicap. We develop a family of agents that can target high scores against any opponent, recover from very severe disadvantage against weak opponents, and avoid suboptimal moves
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