729 research outputs found

    Patterning and process parameter effects in 3D suspension near-field electrospinning of nanoarrays

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    The extracellular matrix (ECM) contains nanofibrous proteins and proteoglycans. Nanofabrication methods have received growing interest in recent years as a means of recapitulating these elements within the ECM. Near-field electrospinning (NFES) is a versatile fibre deposition method, capable of layer-by-layer nano-fabrication. The maximum layer height is generally limited in layer-by-layer NFES as a consequence of electrostatic effects of the polymer at the surface, due to residual charge and polymer dielectric properties. This restricts the total volume achievable by layer-by-layer techniques. Surpassing this restriction presents a complex challenge, leading to research innovations aimed at increasing patterning precision, and achieving a translation from 2D to 3D additive nanofabrication. Here we investigated a means of achieving this translation through the use of 3D electrode substrates. This was addressed by in-house developed technology in which selective laser melt manufactured standing pillar electrodes were combined with a direct suspension near-field electrospinning (SNFES) technique, which implements an automated platform to manoeuvre the pillar electrodes around the emitter in order to suspend fibres in the free space between the electrode support structures. In this study SNFES was used in multiple operation modes, investigating the effects of varying process parameters, as well as pattern variations on the suspended nanoarrays. Image analysis of the nanoarrays allowed for the assessment of fibre directionality, isotropy, and diameter; identifying optimal settings to generate fibres for tissue engineering applications

    In Defense Of Bad Infinity: A Fichtean Response To Hegel's Differenzschrift

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    Hegel's very first acknowledged publication was, among other things, an attack on Fichte. In 1801, Hegel was still laboring in almost complete obscurity, while Fichte was an international sensation, though already somewhat past the peak of his meteoric career. In the 1801 Differenzschrift, Hegel cut his teeth by criticizing Fichte's already widelycriticised Wissenschaftslehre, and by demonstrating that Schelling's philosophical system was not simply to be equated with it. Fichte himself never bothered to respond to Hegel's criticisms; indeed he never publicly acknowledged their existence. This was not because he was unconcerned with criticisms of his views; quite the contrary. But at the time he had bigger fish to fry. He responded to Jacobi's criticisms, and to Schelling's; he replied in great detail to critical questions raised by Reinhold, and with vituperative intensity to objections raised by skeptics and purportedly loyal Kantians. But Hegel's Differenzschrift was left without a Fichtean rebuttal. This is a pity, both because of the missed opportunity to illuminate by controversy central issues at stake in the post-Kantian period, but also because it made it easier for Hegel simply to reiterate his youthful criticism as if it were the last word. And reiterate it he did: in one form or another Hegel's early criticisms of Fichte reappear at every subsequent stage of his career: in the Phenomenology, in the Science of Logic, in the Encyclopaedia, as the final chapter in Hegel's History of Philosophy, and in countless other minor works and documents from the Nachlass and correspondence

    A Weaker Faithfulness Assumption based on Triple Interactions

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    One of the core assumptions in causal discovery is the faithfulness assumption—i.e. assuming that independencies found in the data are due to separations in the true causal graph. This assumption can, however, be violated in many ways, including xor connections, deterministic functions or cancelling paths. In this work, we propose a weaker assumption that we call 2-adjacency faithfulness. In contrast to adjacency faithfulness, which assumes that there is no conditional independence between each pair of variables that are connected in the causal graph, we only require no conditional independence between a node and a subset of its Markov blanket that can contain up to two nodes. Equivalently, we adapt orientation faithfulness to this setting. We further propose a sound orientation rule for causal discovery that applies under weaker assumptions. As a proof of concept, we derive a modified Grow and Shrink algorithm that recovers the Markov blanket of a target node and prove its correctness under strictly weaker assumptions than the standard faithfulness assumption

    Influenza Virus Infection in Travelers to Tropical and Subtropical Countries

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    Background. Influenza outbreaks have been reported among travelers, but attack rates and incidence are unknown. Methods. A cohort study was conducted. Travelers to subtropical and tropical countries recruited at the University of Zurich Travel Clinic (Switzerland), January 1998 to March 2000, were investigated with pre- and posttravel assessment of hemagglutination inhibition and by questionnaire. Results. Among 1450 travelers recruited who completed questionnaires and provided serum samples before departure, 289 (19.9%) reported febrile illness during or after traveling abroad; of these, 211 (73.0%) provided paired serum samples. Additionally, paired serum samples were collected from 321 frequency-matched afebrile control subjects among the remaining 1161 subjects of the study population. Seroconversion for influenza virus infection was demonstrated in 40 (2.8%) of all travelers; 18 participants (1.2%) had a ⩾4-fold increase in antibody titers. This corresponds to an incidence of 1.0 influenza-associated events per 100 person-months abroad. Among the 211 febrile participants, 27 (12.8%) had seroconversion, 13 (6.2%) with a ⩾4-fold increase; among the 321 afebrile control subjects, 13 (4.0%) had seroconversion, 5 (1.6%) with a ⩾4-fold increase. Twenty-five seroconverters (62.5%; P = .747) acquired influenza outside of the European epidemic season. Sixteen patients (40.0%) sought medical attention either abroad or at home, and 32 (80.0%) were asymptomatic at the time of completion of the survey. Conclusions. This survey indicates that influenza is the most frequent vaccine-preventable infection among travelers to subtropical and tropical countries. Infections occur mainly outside the domestic epidemic season, and they have a considerable impact. Pretravel vaccination should be considered for travelers to subtropical and tropical countrie

    IZA COVID-19 Crisis response monitoring: The second phase of the crisis

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    Grupo de autores, para além dos nacionais: Werner Eichhorst, Paul Marx, Ulf Rinne, René Böheim, Thomas Leoni, Steven Tobin, Arthur Sweetman, Pierre Cahuc, Tommaso Colussi, Egbert L. W. Jongen, Paul Verstraten, Priscila Ferreira, João Cerejeira, Miguel Portela, Raul Ramos, Martin Kahanec, Monika Martiskova, Lena Hensvik, Oskar Nordström Skans, Patrick Arni, Rui Costa, Stephen Machin, Susan N. HousemanAs the pandemic continues and countries experience a massive second wave, labor markets continue to be heavily affected. At the same time, countries have started to extend, but also adjust stabilization measures initially introduced at the outset of the crisis. As of today, three main elements of crisis response require particular attention: the further development of short-time work schemes, ad hoc income protection for the self-employed, and the specific difficulties labor markets are currently facing. This overview addresses focusses on these three essential issues

    Position and Role of the BK Channel α Subunit S0 Helix Inferred from Disulfide Crosslinking

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    The position and role of the unique N-terminal transmembrane (TM) helix, S0, in large-conductance, voltage- and calcium-activated potassium (BK) channels are undetermined. From the extents of intra-subunit, endogenous disulfide bond formation between cysteines substituted for the residues just outside the membrane domain, we infer that the extracellular flank of S0 is surrounded on three sides by the extracellular flanks of TM helices S1 and S2 and the four-residue extracellular loop between S3 and S4. Eight different double cysteine–substituted alphas, each with one cysteine in the S0 flank and one in the S3–S4 loop, were at least 90% disulfide cross-linked. Two of these alphas formed channels in which 90% cross-linking had no effect on the V50 or on the activation and deactivation rate constants. This implies that the extracellular ends of S0, S3, and S4 are close in the resting state and move in concert during voltage sensor activation. The association of S0 with the gating charge bearing S3 and S4 could contribute to the considerably larger electrostatic energy required to activate the BK channel compared with typical voltage-gated potassium channels with six TM helices

    Self-interest And Public Interest: The Motivations Of Political Actors

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    Self-Interest and Public Interest in Western Politics showed that the public, politicians, and bureaucrats are often public spirited. But this does not invalidate public-choice theory. Public-choice theory is an ideal type, not a claim that self-interest explains all political behavior. Instead, public-choice theory is useful in creating rules and institutions that guard against the worst case, which would be universal self-interestedness in politics. In contrast, the public-interest hypothesis is neither a comprehensive explanation of political behavior nor a sound basis for institutional design

    Wide-Field InfraRed Survey Telescope (WFIRST) Slitless Spectrometer: Design, Prototype, and Results

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    The slitless spectrometer plays an important role in the Wide-Field InfraRed Survey Telescope (WFIRST) mission for the survey of emission-line galaxies. This will be an unprecedented very wide field, HST quality 3D survey of emission line galaxies. The concept of the compound grism as a slitless spectrometer has been presented previously. The presentation briefly discusses the challenges and solutions of the optical design, and recent specification updates, as well as a brief comparison between the prototype and the latest design. However, the emphasis of this paper is the progress of the grism prototype: the fabrication and test of the complicated diffractive optical elements and powered prism, as well as grism assembly alignment and testing. Especially how to use different tools and methods, such as IR phase shift and wavelength shift interferometry, to complete the element and assembly tests. The paper also presents very encouraging results from recent element tests to assembly tests. Finally we briefly touch the path forward plan to test the spectral characteristic, such as spectral resolution and response

    Definitions and Assessment Approaches for Emergency Medical Services for Children

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    Pediatric Life Support (PLS) courses and instructional programs are educational tools developed to teach resuscitation and stabilization of children who are critically ill or injured. A number of PLS courses have been developed by national professional organizations for different health care providers (eg, pediatricians, emergency physicians, other physicians, prehospital professionals, pediatric and emergency advanced practice nurses, physician assistants). PLS courses and programs have attempted to clarify and standardize assessment and treatment approaches for clinical practice in emergency, trauma, and critical care. Although the effectiveness of PLS education has not yet been scientifically validated, the courses and programs have significantly expanded pediatric resuscitation training throughout the United States and internationally. Variability in terminology and in assessment components used in education and training among PLS courses has the potential to create confusion among target groups and in how experts train educators and learners to teach and practice pediatric emergency, trauma, and critical care. It is critical that all educators use standard terminology and patient assessment to address potential or actual conflicts regarding patient evaluation and treatment. This article provides a consensus of several organizations as to the proper order and terminology for pediatric patient assessment. The Supplemental Information provides definitions for terms and nomenclature used in pediatric resuscitation and life support courses
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