The strange evolution of the Large Magellanic Cloud Cepheid OGLE-LMC-CEP1812

Classical Cepheids are key probes of both stellar astrophysics and cosmology as standard candles and pulsating variable stars. It is important to understand Cepheids in unprecedented detail in preparation for upcoming GAIA, JWST and extremely-large telescope observations. Cepheid eclipsing binary stars are ideal tools for achieving this goal, however there are currently only three known systems. One of those systems, OGLE-LMC-CEP1812, raises new questions about the evolution of classical Cepheids because of an apparent age discrepancy between the Cepheid and its red giant companion. We show that the Cepheid component is actually the product of a stellar merger of two main sequence stars that has since evolved across the Hertzsprung gap of the HR diagram. This post-merger product appears younger than the companion, hence the apparent age discrepancy is resolved. We discuss this idea and consequences for understanding Cepheid evolution.Comment: 5 pages, 3 figures, accepted to A&

How to Deal with Non-Dominant Languages – Metalinguistic Discourses on Low German in the Nineteenth Century

This paper discusses nineteenth-century metalinguistic discussions of Low German, an authochthonous of Northern Germany, which, having lost its status as a written language suitable for formal discourse during the Early Modern period, has since been reduced to the spoken domain. During the nineteenth century the language was on the verge of enjoying a revival, with original poetry being published and extensive discussions as to whether Low German ought to play a role in formal education. As this article shows, this discussion was intense and controversial. Comparing the views of Klaus Groth, the leading proponent of Low German in the second half of the nineteenth century, with the internal debates amongst school teachers - hitherto never discussed by the scholarly literature – this article demonstrates the intellectual and ideological split felt by these educational practioners in their views of Low German: on the one hand, they recognise the cultural value of Low German as the historical language of the North and the native language of the pupils they teach, on the other hand they agree with each other that the language of education and science, as well as national unity, can only be High German. We hope to show with our discussion not only how very similar modern thinking on the use of Low German is to these historical discussions but also how the status and perception of many regional and minority languages across the world has been subject to the same or very similar thoughts and pressures

Microfluidic technologies for accelerating the clinical translation of nanoparticles

Using nanoparticles for therapy and imaging holds tremendous promise for the treatment of major diseases such as cancer. However, their translation into the clinic has been slow because it remains difficult to produce nanoparticles that are consistent 'batch-to-batch', and in sufficient quantities for clinical research. Moreover, platforms for rapid screening of nanoparticles are still lacking. Recent microfluidic technologies can tackle some of these issues, and offer a way to accelerate the clinical translation of nanoparticles. In this Progress Article, we highlight the advances in microfluidic systems that can synthesize libraries of nanoparticles in a well-controlled, reproducible and high-throughput manner. We also discuss the use of microfluidics for rapidly evaluating nanoparticles in vitro under microenvironments that mimic the in vivo conditions. Furthermore, we highlight some systems that can manipulate small organisms, which could be used for evaluating the in vivo toxicity of nanoparticles or for drug screening. We conclude with a critical assessment of the near- and long-term impact of microfluidics in the field of nanomedicine.Prostate Cancer Foundation (Award in Nanotherapeutics)MIT-Harvard Center for Cancer Nanotechnology Excellence (U54-CA151884)National Heart, Lung, and Blood Institute (Programs of Excellence in Nanotechnology (HHSN268201000045C))National Science Foundation (U.S.) (Graduate Research Fellowship

Classical Cepheids Require Enhanced Mass Loss

Measurements of rates of period change of Classical Cepheids probe stellar physics and evolution. Additionally, better understanding of Cepheid structure and evolution provides greater insight into their use as standard candles and tools for measuring the Hubble constant. Our recent study of the period change of the nearest Cepheid, Polaris, suggested that it is undergoing enhanced mass loss when compared to canonical stellar evolution model predictions. In this work, we expand the analysis to rates of period change measured for about 200 Galactic Cepheids and compare them to population synthesis models of Cepheids including convective core overshooting and enhanced mass loss. Rates of period change predicted from stellar evolution models without mass loss do not agree with observed rates whereas including enhanced mass loss yields predicted rates in better agreement with observations. This is the first evidence that enhanced mass loss as suggested previously for Polaris and delta Cephei must be a ubiquitous property of Classical Cepheids.Comment: 6 pages, 4 figures, Accepted for publication in ApJ Letter

Fast rotating stars resulting from binary evolution will often appear to be single

Rapidly rotating stars are readily produced in binary systems. An accreting star in a binary system can be spun up by mass accretion and quickly approach the break-up limit. Mergers between two stars in a binary are expected to result in massive, fast rotating stars. These rapid rotators may appear as Be or Oe stars or at low metallicity they may be progenitors of long gamma-ray bursts. Given the high frequency of massive stars in close binaries it seems likely that a large fraction of rapidly rotating stars result from binary interaction. It is not straightforward to distinguish a a fast rotator that was born as a rapidly rotating single star from a fast rotator that resulted from some kind of binary interaction. Rapidly rotating stars resulting from binary interaction will often appear to be single because the companion tends to be a low mass, low luminosity star in a wide orbit. Alternatively, they became single stars after a merger or disruption of the binary system during the supernova explosion of the primary. The absence of evidence for a companion does not guarantee that the system did not experience binary interaction in the past. If binary interaction is one of the main causes of high stellar rotation rates, the binary fraction is expected to be smaller among fast rotators. How this prediction depend on uncertainties in the physics of the binary interactions requires further investigation.Comment: 2 pages, 1 figure, to be published in the proceedings of IAU 272 "Active OB stars: structure, evolution, mass loss and critical limit", Paris 19-23 July 201

The Engineering of Biology and Medicine

In celebration of the 100th Anniversary of PNAS, this Special Feature summarizes the enormous progress that has been made in the engineering of biology and medicine

Designing materials for biology and medicine

Biomaterials have played an enormous role in the success of medical devices and drug delivery systems. We discuss here new challenges and directions in biomaterials research. These include synthetic replacements for biological tissues, designing materials for specific medical applications, and materials for new applications such as diagnostics and array technologies

The occurrence of classical Cepheids in binary systems

Classical Cepheids, like binary stars, are laboratories for stellar evolution and Cepheids in binary systems are especially powerful ones. About one-third of Galactic Cepheids are known to have companions and Cepheids in eclipsing binary systems have recently been discovered in the Large Magellanic Cloud. However, there are no known Galactic binary Cepheids with orbital periods less than one year. We compute population synthesis models of binary Cepheids to compare to the observed period and eccentricity distributions of Galactic Cepheids as well as to the number of observed eclipsing binary Cepheids in the LMC. We find that our population synthesis models are consistent with observed binary properties of Cepheids. Furthermore, we show that binary interaction on the red giant branch prevents some red giant stars from becoming classical Cepheids. Such interactions suggest that the binary fraction of Cepheids should be significantly less than that of their main-sequence progenitors, and that almost all binary Cepheids have orbital periods longer than one year. If the Galactic Cepheid spectroscopic binary fraction is about 35%, then the spectroscopic binary fraction of their intermediate mass main sequence progenitors is about 40-45%.Comment: 7 pages, 3 figures, resubmitted to A&

mRNA therapy at the convergence of genetics and nanomedicine

OKJ.C. acknowledges the European Research Council Starting Grant (ERC-StG-2019-848325).publishersversionpublishe