One-pot synthesis of responsive sulfobetaine nanoparticles by RAFT polymerisation: the effect of branching on the UCST cloud point

We describe the one-pot synthesis of temperature-responsive branched polymer nanoparticles. Reversible addition–fragmentation chain transfer (RAFT) polymerisation has been utilised to synthesise ultra-high molecular weight sulfobetaine polymers (up to ca. 500 kDa) with good control over molecular weight (Mn) and dispersity (Mw/Mn). The UCST cloud points of these linear polymers were found to increase with both Mn and concentration, and represent one of the few recent descriptions of polymers exhibiting UCST behaviour in aqueous solution. The incorporation of difunctional monomers results in branched polymers which display vastly reduced transition temperatures compared to their linear counterparts. Furthermore, the incorporation of a permanently hydrophilic monomer results in the formation of stable core–shell particles which no longer exhibit a cloud point in water, even at very high concentrations (ca. 50 mg mL−1). The branched polymers are shown to form discrete well-defined nanoparticles in aqueous solution, and these have been characterised by DLS, SLS, TEM and DOSY. Their reversible swelling behaviour in response to temperature is also demonstrated

High-resolution ab initio three-dimensional X-ray diffraction microscopy

Coherent X-ray diffraction microscopy is a method of imaging non-periodic isolated objects at resolutions only limited, in principle, by the largest scattering angles recorded. We demonstrate X-ray diffraction imaging with high resolution in all three dimensions, as determined by a quantitative analysis of the reconstructed volume images. These images are retrieved from the 3D diffraction data using no a priori knowledge about the shape or composition of the object, which has never before been demonstrated on a non-periodic object. We also construct 2D images of thick objects with infinite depth of focus (without loss of transverse spatial resolution). These methods can be used to image biological and materials science samples at high resolution using X-ray undulator radiation, and establishes the techniques to be used in atomic-resolution ultrafast imaging at X-ray free-electron laser sources.Comment: 22 pages, 11 figures, submitte

COVID-19 reveals the systemic nature of urban health globally

Statement by the scientific committee* of the International Science Council’s Programme on Urban Health and Wellbeing, on critical elements of urban health action in response to the epidemic

Less than 10 percent of star formation in z=0.6 massive galaxies is triggered by major interactions

Both observations and simulations show that major tidal interactions or mergers between gas-rich galaxies can lead to intense bursts of starformation. Yet, the average enhancement in star formation rate (SFR) in major mergers and the contribution of such events to the cosmic SFR are not well estimated. Here we use photometric redshifts, stellar masses and UV SFRs from COMBO-17, 24 micron SFRs from Spitzer and morphologies from two deep HST cosmological survey fields (ECDFS/GEMS and A901/STAGES) to study the enhancement in SFR as a function of projected galaxy separation. We apply two-point projected correlation function techniques, which we augment with morphologically-selected very close pairs (separation <2 arcsec) and merger remnants from the HST imaging. Our analysis confirms that the most intensely star-forming systems are indeed interacting or merging. Yet, for massive (M* > 10^10 Msun) star-forming galaxies at 0.4<z<0.8, we find that the SFRs of galaxies undergoing a major interaction (mass ratios <1:4 and separations < 40 kpc) are only 1.80 +/- 0.30 times higher than the SFRs of non-interacting galaxies when averaged over all interactions and all stages of the interaction, in good agreement with other observational works. We demonstrate that these results imply that <10% of star formation at 0.4 < z < 0.8 is triggered directly by major mergers and interactions; these events are not important factors in the build-up of stellar mass since z=1.Comment: Submitted to ApJ. 41 pages, 11 figure

An ammonia spectral map of the L1495-B218 filaments in the Taurus molecular cloud. I. Physical properties of filaments and dense cores

We present deep NH3 observations of the L1495-B218 filaments in the Taurus molecular cloud covering over a 3° angular range using the K-band focal plane array on the 100 m Green Bank Telescope. The L1495-B218 filaments form an interconnected, nearby, large complex extending over 8 pc. We observed NH3 (1, 1) and (2, 2) with a spectral resolution of 0.038 km s−1 and a spatial resolution of 31''. Most of the ammonia peaks coincide with intensity peaks in dust continuum maps at 350 and 500 μm. We deduced physical properties by fitting a model to the observed spectra. We find gas kinetic temperatures of 8–15 K, velocity dispersions of 0.05–0.25 km s−1, and NH3 column densities of 5 × 1012 to 1 × 1014 cm−2. The CSAR algorithm, which is a hybrid of seeded-watershed and binary dendrogram algorithms, identifies a total of 55 NH3 structures, including 39 leaves and 16 branches. The masses of the NH3 sources range from 0.05 to 9.5 ${{M}_{\odot }}$. The masses of NH3 leaves are mostly smaller than their corresponding virial mass estimated from their internal and gravitational energies, which suggests that these leaves are gravitationally unbound structures. Nine out of 39 NH3 leaves are gravitationally bound, and seven out of nine gravitationally bound NH3 leaves are associated with star formation. We also found that 12 out of 30 gravitationally unbound leaves are pressure confined. Our data suggest that a dense core may form as a pressure-confined structure, evolve to a gravitationally bound core, and undergo collapse to form a protostar

American Cancer Society/American Society of Clinical Oncology Breast Cancer Survivorship Care Guideline

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/136493/1/caac21319_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/136493/2/caac21319-sup-0001-suppinfo1.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/136493/3/caac21319.pd

Galaxy Properties from the Ultra-violet to the Far-Infrared: Lambda-CDM models confront observations

We combine a semi-analytic model of galaxy formation with simple analytic recipes describing the absorption and re-emission of starlight by dust in the interstellar medium of galaxies. We use the resulting models to predict galaxy counts and luminosity functions from the far-ultraviolet to the sub-mm, from redshift five to the present, and compare with an extensive compilation of observations. We find that in order to reproduce the rest-UV and optical luminosity functions at high redshift, we must assume an evolving normalization in the dust-to-metal ratio, implying that galaxies of a given bolometric luminosity (or metal column density) must be less extinguished than their local counterparts. In our best-fit model, we find remarkably good agreement with observations from rest-frame 1500 Angstroms to 250 microns. At longer wavelengths, most dramatically in the sub-mm, our models underpredict the number of bright galaxies by a large factor. The models reproduce the observed total IR luminosity function fairly well. We show the results of varying several ingredients of the models, including various aspects of the dust attenuation recipe, the dust emission templates, and the cosmology. We use our models to predict the integrated Extragalactic Background Light (EBL), and compare with an observationally-motivated EBL model and with other available observational constraints.Comment: 27 pages, 17 figures, 1 table, accepted to MNRAS, this version matches accepted manuscrip

The One with the Feminist Critique: Revisiting Millennial Postfeminism with Friends

In the aftermath of its initial broadcast run, iconic millennial sitcom Friends (NBC, 1994–2004) generated some quality scholarship interrogating its politics of gender. But as a site of analysis, it remains a curious, almost structuring absence from the central canon of the first wave of feminist criticism of postfeminist culture. This absence is curious not only considering the place of Friends at the forefront of millennial popular culture but also in light of its long-term syndication in countries across the world since that time. And it is structuring in the sense that Friends was the stage on which many of the familiar tropes of postfeminism interrogated across the body of work on it appear in retrospect to have been tried and tested. This article aims to contribute toward redressing this absence through interrogation and contextualization of the series’ negotiation of a range of structuring tropes of postfeminist media discourse, and it argues for Friends as an unacknowledged ur-text of millennial postfeminism

CLIMB-COVID: continuous integration supporting decentralised sequencing for SARS-CoV-2 genomic surveillance.

Funder: Wellcome TrustIn response to the ongoing SARS-CoV-2 pandemic in the UK, the COVID-19 Genomics UK (COG-UK) consortium was formed to rapidly sequence SARS-CoV-2 genomes as part of a national-scale genomic surveillance strategy. The network consists of universities, academic institutes, regional sequencing centres and the four UK Public Health Agencies. We describe the development and deployment of CLIMB-COVID, an encompassing digital infrastructure to address the challenge of collecting and integrating both genomic sequencing data and sample-associated metadata produced across the COG-UK network