Oscillatory Shear Flow-Induced Alignment of Lamellar Melts of Hydrogen-Bonded Comb Copolymer Supramolecules

In this work we present the orientational behavior of comb copolymer-like supramolecules P4VP(PDP)1.0, obtained by hydrogen bonding between poly(4-vinylpyridine) and pentadecylphenol, during large-amplitude oscillatory shear flow experiments over a broad range of frequencies (0.001-10 Hz). The alignment diagram, presenting the macroscopic alignment in T/TODT vs ω/ωc, contains three regions of parallel alignment separated by a region of perpendicular alignment. For our material, the order-disorder temperature TODT = 67 °C and ωc, the frequency above which the distortion of the chain conformation dominates the materials’ viscoelasticity, is around 0.1 Hz at 61 °C. For the first time flipping from a pure transverse alignment via biaxial transverse/perpendicular alignment to a perpendicular alignment as a function of the strain amplitude was found.

Spectroscopic signatures of youth in low-mass kinematic candidates of young moving groups

This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2014 by the Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.We present a study of age-related spectral signatures observed in 25 young low-mass objects that we have previously determined as possible kinematic members of five young moving groups: the Local Association (Pleiades moving group, age = 20–150 Myr), the Ursa Major group (Sirius supercluster, age = 300 Myr), the Hyades supercluster (age = 600 Myr), IC 2391 supercluster (age = 35–55 Myr) and the Castor moving group (age = 200 Myr). In this paper we characterize the spectral properties of observed high- or low-resolution spectra of our kinematic members by fitting theoretical spectral distributions. We study signatures of youth, such as lithium I 6708Å, Hα emission and other age-sensitive spectroscopic signatures in order to confirm the kinematic memberships through age constraints. We find that 21 (84 per cent) targets show spectroscopic signatures of youth in agreement with the age ranges of the moving group to which membership is implied. For two further objects, age-related constraints remain difficult to determine from our analysis. In addition, we confirm two moving group kinematic candidates as brown dwarfs.Peer reviewe

VVV High proper motion stars I. The catalogue of bright Ks stars

The final, definitive version of this paper has been published in Monthly Notices of the Royal Astronomical Society, Vol. 464(1): 1247-1258, January 2017, DOI: 10.1093/mnras/stw2357, first published on line September 16, 2016, published by Oxford University Press on behalf of MNRAS.Knowledge of the stellar content near the Sun is important for a broad range of topics ranging from the search for planets to the study of Milky Way structure. The most powerful method for identifying potentially nearby stars is proper motion (PM) surveys. All old optical surveys avoid, or are at least substantially incomplete, near the Galactic plane. The depth and breadth of the "Vista Variables in Via Lactea" (VVV) near-IR survey significantly improves this situation. Taking advantage of the VVV survey database, we have measured PMs in the densest regions of the MW bulge and southern plane in order to complete the census of nearby objects. We have developed a custom PM pipeline based on VVV catalogues from the Cambridge Astronomy Survey Unit (CASU), by comparing the first epoch of JHKs with the multi-epoch Ks-bands acquired later. Taking advantage of the large time baseline between the 2MASS and the VVV observations, we also obtained 2MASS-VVV PMs. We present a near-IR proper motion catalogue for the whole area of the VVV survey, which includes 3003 moving stellar sources. All of these have been visually inspected and are real PM objects. Our catalogue is in very good agreement with the proper motion data supplied in IR catalogues outside the densest zone of the MW. The majority of the PM objects in our catalogue are nearby M-dwarfs, as expected. This new database allow us to identify 57 common proper motion binary candidates, among which are two new systems within ~30pc of the Sun.Peer reviewe

Tree structure of the percolating Universe

We present a numerical study of topological descriptors of initially Gaussian and scale-free density perturbations evolving via gravitational instability in an expanding universe. We carefully evaluate and avoid numerical contamination in making accurate measurements on simulated fields on a grid in a finite box. Independent of extent of non linearity, the measured Euler number of the excursion set at the percolation threshold, $\delta_c$, is positive and nearly equal to the number of isolated components, suggesting that these structures are trees. Our study of critical point counts reconciles the clumpy appearance of the density field at $\delta_c$ with measured filamentary local curvature. In the Gaussian limit, we measure $|\delta_c|> \sigma$ in contrast to widely held belief that $|\delta_c| \sim \sigma$, where $\sigma^2$ is the variance of the density field.Comment: 4 pages, 2 figures, Accepted for publication in Phys. Rev. Let

Simulating the Formation of the Local Galaxy Population

We simulate the formation and evolution of the local galaxy population starting from initial conditions with a smoothed linear density field which matches that derived from the IRAS 1.2 Jy galaxy survey. Our simulations track the formation and evolution of all dark matter haloes more massive than 10e+11 solar masses out to a distance of 8000 km/s from the Milky Way. We implement prescriptions similar to those of Kauffmann et al. (1999) to follow the assembly and evolution of the galaxies within these haloes. We focus on two variants of the CDM cosmology: an LCDM and a tCDM model. Galaxy formation in each is adjusted to reproduce the I-band Tully-Fisher relation of Giovanelli et al. (1997). We compare the present-day luminosity functions, colours, morphology and spatial distribution of our simulated galaxies with those of the real local population, in particular with the Updated Zwicky Catalog, with the IRAS PSCz redshift survey, and with individual local clusters such as Coma, Virgo and Perseus. We also use the simulations to study the clustering bias between the dark matter and galaxies of differing type. Although some significant discrepancies remain, our simulations recover the observed intrinsic properties and the observed spatial distribution of local galaxies reasonably well. They can thus be used to calibrate methods which use the observed local galaxy population to estimate the cosmic density parameter or to draw conclusions about the mechanisms of galaxy formation. To facilitate such work, we publically release our z=0 galaxy catalogues, together with the underlying mass distribution.Comment: 25 pages, 20 figures, submitted to MNRAS. High resolution copies of figures 1 and 3, halo and galaxy catalogues can be found at http://www.mpa-garching.mpg.de/NumCos/CR/index.htm

ENDOR Spectroscopy and DFT Calculations: Evidence for the Hydrogen-Bond Network Within α2 in the PCET of E. coli Ribonucleotide Reductase

Escherichia coli class I ribonucleotide reductase (RNR) catalyzes the conversion of nucleotides to deoxynucleotides and is composed of two subunits: α2 and β2. β2 contains a stable di-iron tyrosyl radical (Y[subscript 122]•) cofactor required to generate a thiyl radical (C[subscript 439]•) in α2 over a distance of 35 Å, which in turn initiates the chemistry of the reduction process. The radical transfer process is proposed to occur by proton-coupled electron transfer (PCET) via a specific pathway: Y[subscript 122] ⇆ W[subscript 48][?] ⇆ Y[subscript 356] in β2, across the subunit interface to Y[subscript 731] ⇆ Y[subscript 730] ⇆ C[subscript 439] in α2. Within α2 a colinear PCET model has been proposed. To obtain evidence for this model, 3-amino tyrosine (NH2Y) replaced Y[subscript 730] in α2, and this mutant was incubated with β2, cytidine 5′-diphosphate, and adenosine 5′-triphosphate to generate a NH2Y730• in D2O. [[superscript 2]H]-Electron–nuclear double resonance (ENDOR) spectra at 94 GHz of this intermediate were obtained, and together with DFT models of α2 and quantum chemical calculations allowed assignment of the prominent ENDOR features to two hydrogen bonds likely associated with C[subscript 439] and Y[subscript 731]. A third proton was assigned to a water molecule in close proximity (2.2 Å O–H···O distance) to residue 730. The calculations also suggest that the unusual g-values measured for NH[subscript 2]Y[subscript 730]• are consistent with the combined effect of the hydrogen bonds to Cys[subscript 439] and Tyr[subscript 731], both nearly perpendicular to the ring plane of NH[subscript 2]Y[subscript 730]. The results provide the first experimental evidence for the hydrogen-bond network between the pathway residues in α2 of the active RNR complex, for which no structural data are available.National Institutes of Health (U.S.) (NIH GM29595

Deconstructing the outsider puzzle: The legitimation journey of novelty

The proposition that outsiders often are crucial carriers of novelty into an established institutional field has received wide empirical support. But an equally compelling proposition points to the following puzzle: the very same conditions that enhance outsiders' ability to make novel contributions also hinder their ability to carry them out. We seek to address this puzzle by examining the contextual circumstances that affect the legitimation of novelty originating from a noncertified outsider that challenged the status quo in an established institutional field. Our research case material is John Harrison's introduction of a new mechanical method for measuring longitude at sea-the marine chronometer- which challenged the dominant astronomical approach.We find that whether an outsider's new offer gains or is denied legitimacy is influenced by (1) the outsider's agency to further a new offer, (2) the existence of multiple audiences with different dispositions toward this offer, and (3) the occurrence of an exogenous jolt that helps create a more receptive social space. We organize these insights into a multilevel conceptual framework that builds on previouswork but attributes a more decisive role to the interplay between endogenous and exogenous variables in shaping a field's shifting receptiveness to novelty. The framework exposes the interdependencies between the micro-, meso-, and macro-level processes that jointly affect an outsider's efforts to introduce novelty into an existing field

PIK3CA dependence and sensitivity to therapeutic targeting in urothelial carcinoma

Background Many urothelial carcinomas (UC) contain activating PIK3CA mutations. In telomerase-immortalized normal urothelial cells (TERT-NHUC), ectopic expression of mutant PIK3CA induces PI3K pathway activation, cell proliferation and cell migration. However, it is not clear whether advanced UC tumors are PIK3CA-dependent and whether PI3K pathway inhibition is a good therapeutic option in such cases. Methods We used retrovirus-mediated delivery of shRNA to knock down mutant PIK3CA in UC cell lines and assessed effects on pathway activation, cell proliferation, migration and tumorigenicity. The effect of the class I PI3K inhibitor GDC-0941 was assessed in a panel of UC cell lines with a range of known molecular alterations in the PI3K pathway. Results Specific knockdown of PIK3CA inhibited proliferation, migration, anchorage-independent growth and in vivo tumor growth of cells with PIK3CA mutations. Sensitivity to GDC-0941 was dependent on hotspot PIK3CA mutation status. Cells with rare PIK3CA mutations and co-occurring TSC1 or PTEN mutations were less sensitive. Furthermore, downstream PI3K pathway alterations in TSC1 or PTEN or co-occurring AKT1 and RAS gene mutations were associated with GDC-0941 resistance. Conclusions Mutant PIK3CA is a potent oncogenic driver in many UC cell lines and may represent a valuable therapeutic target in advanced bladder cancer

Customer emotions in service failure and recovery encounters

Emotions play a significant role in the workplace, and considerable attention has been given to the study of employee emotions. Customers also play a central function in organizations, but much less is known about customer emotions. This chapter reviews the growing literature on customer emotions in employee–customer interfaces with a focus on service failure and recovery encounters, where emotions are heightened. It highlights emerging themes and key findings, addresses the measurement, modeling, and management of customer emotions, and identifies future research streams. Attention is given to emotional contagion, relationships between affective and cognitive processes, customer anger, customer rage, and individual differences

Whole-genome sequencing reveals host factors underlying critical COVID-19

Critical COVID-19 is caused by immune-mediated inflammatory lung injury. Host genetic variation influences the development of illness requiring critical care1 or hospitalization2–4 after infection with SARS-CoV-2. The GenOMICC (Genetics of Mortality in Critical Care) study enables the comparison of genomes from individuals who are critically ill with those of population controls to find underlying disease mechanisms. Here we use whole-genome sequencing in 7,491 critically ill individuals compared with 48,400 controls to discover and replicate 23 independent variants that significantly predispose to critical COVID-19. We identify 16 new independent associations, including variants within genes that are involved in interferon signalling (IL10RB and PLSCR1), leucocyte differentiation (BCL11A) and blood-type antigen secretor status (FUT2). Using transcriptome-wide association and colocalization to infer the effect of gene expression on disease severity, we find evidence that implicates multiple genes—including reduced expression of a membrane flippase (ATP11A), and increased expression of a mucin (MUC1)—in critical disease. Mendelian randomization provides evidence in support of causal roles for myeloid cell adhesion molecules (SELE, ICAM5 and CD209) and the coagulation factor F8, all of which are potentially druggable targets. Our results are broadly consistent with a multi-component model of COVID-19 pathophysiology, in which at least two distinct mechanisms can predispose to life-threatening disease: failure to control viral replication; or an enhanced tendency towards pulmonary inflammation and intravascular coagulation. We show that comparison between cases of critical illness and population controls is highly efficient for the detection of therapeutically relevant mechanisms of disease