bluuebunny/crossref_metadata_2025_split huggingface dataset:
General and Practical Formation of Thiocyanates from Thiols
Authors: Frei Reto , Courant Thibaut , Wodrich Matthew D. , Waser Jerome 
Published: December 2014

AbstractA new method for the cyanation of thiols and disulfides using cyanobenziodoxol(on)e hypervalent iodine reagents is described. Both aliphatic and aromatic thiocyanates can be accessed in good yields in a few minutes at room temperature starting from a broad range of thiols with high chemioselectivity. The complete conversion of disulfides to thiocyanates was also possible. Preliminary computational studies indicated a low energy concerted transition state for the cyanation of the thiolate anion or radical. The developed thiocyanate synthesis has broad potential for various applications in synthetic chemistry, chemical biology and materials science.
A second corticotropin‐releasing hormone gene (CRH2) is conserved across vertebrate classes and expressed in the hindbrain of a basal Neopterygian fish, the spotted gar (Lepisosteus oculatus)
Authors: Grone Brian P. , Maruska Karen P. 
Published: December 2014

ABSTRACTTo investigate the origins of the vertebrate stress‐response system, we searched sequenced vertebrate genomes for genes resembling corticotropin‐releasing hormone (CRH). We found that vertebrate genomes possess, in addition to CRH, another gene that resembles CRH in sequence and syntenic environment. This paralogous gene was previously identified only in the elephant shark (a holocephalan), but we find it also in marsupials, monotremes, lizards, turtles, birds, and fishes. We examined the relationship of this second vertebrate CRH gene, which we name CRH2, to CRH1 (previously known as CRH) and urocortin1/urotensin1 (UCN1/UTS1) in primitive fishes, teleosts, and tetrapods. The paralogs CRH1 and CRH2 likely evolved via duplication of CRH during a whole‐genome duplication early in the vertebrate lineage. CRH2 was subsequently lost in both teleost fishes and eutherian mammals but retained in other lineages. To determine where CRH2 is expressed relative to CRH1 and UTS1, we used in situ hybridization on brain tissue from spotted gar (Lepisosteus oculatus), a neopterygian fish closely related to teleosts. In situ hybridization revealed widespread distribution of both crh1 and uts1 in the brain. Expression of crh2 was restricted to the putative secondary gustatory/secondary visceral nucleus, which also expressed calcitonin‐related polypeptide alpha (calca), a marker of parabrachial nucleus in mammals. Thus, the evolutionary history of CRH2 includes restricted expression in the brain, sequence changes, and gene loss, likely reflecting release of selective constraints following whole‐genome duplication. The discovery of CRH2 opens many new possibilities for understanding the diverse functions of the CRH family of peptides across vertebrates. J. Comp. Neurol. 523:1125–1143, 2015. © 2015 Wiley Periodicals, Inc.
Characteristic Classes of Singular Toric Varieties
Authors: Maxim Laurenţiu G. , Schürmann Jörg 
Published: December 2014

AbstractIn this paper we compute the motivic Chern classes and homology Hirzebruch characteristic classes of (possibly singular) toric varieties, which in the context of complete toric varieties fit nicely with a generalized Hirzebruch‐Riemann‐Roch theorem. As important special cases, we obtain new (or recover well‐known) formulae for the Baum‐Fulton‐MacPherson Todd (or MacPherson's Chern) classes of toric varieties, as well as for the Thom‐Milnor L‐classes of simplicial projective toric varieties. We present two different perspectives for the computation of these characteristic classes of toric varieties. First, we take advantage of the torus‐orbit decomposition and the motivic properties of the motivic Chern and respectively homology Hirzebruch classes to express the latter in terms of dualizing sheaves and respectively the (dual) Todd classes of closures of orbits. This method even applies to torus‐invariant subspaces of a given toric variety. The obtained formula is then applied to weighted lattice‐point counting in lattice polytopes and their subcomplexes, yielding generalized Pick‐type formulae. Second, in the case of simplicial toric varieties, we compute our characteristic classes by using the Lefschetz‐Riemann‐Roch theorem of Edidin‐Graham in the context of the geometric quotient description of such varieties. In this setting, we define mock Hirzebruch classes of simplicial toric varieties (which specialize to the mock Chern, mock Todd, and mock L‐classes of such varieties) and investigate the difference between the (actual) homology Hirzebruch class and the mock Hirzebruch class. We show that this difference is localized on the singular locus, and we obtain a formula for it in which the contribution of each singular cone is identified explicitly. Finally, the two methods of computing characteristic classes are combined for proving several characteristic class formulae originally obtained by Cappell and Shaneson in the early 1990s.© 2015 Wiley Periodicals, Inc.
Response Patterns in Health State Valuation Using Endogenous Attribute Attendance and Latent Class Analysis
Authors: Hole Arne Risa , Norman Richard , Viney Rosalie 
Published: December 2014

SummaryNot accounting for simplifying decision‐making heuristics when modelling data from discrete choice experiments has been shown potentially to lead to biased inferences. This study considers two ways of exploring the presence of attribute non‐attendance (that is, respondents considering only a subset of the attributes that define the choice options) in a health state valuation discrete choice experiment. The methods used include the latent class (LC) and endogenous attribute attendance (EAA) models, which both required adjustment to reflect the structure of the quality‐adjusted life year (QALY) framework for valuing health outcomes. We find that explicit consideration of attendance patterns substantially improves model fit. The impact of allowing for non‐attendance on the estimated QALY weights is dependent on the assumed source of non‐attendance. If non‐attendance is interpreted as a form of preference heterogeneity, then the inferences from the LC and EAA models are similar to those from standard models, while if respondents ignore attributes to simplify the choice task, the QALY weights differ from those using the standard approach. Because the cause of non‐attendance is unknown in the absence of additional data, a policymaker may use the range of weights implied by the two approaches to conduct a sensitivity analysis. Copyright © 2014 John Wiley & Sons, Ltd.
Mixing Homomorphisms, Recolorings, and Extending Circular Precolorings
Authors: Brewster Richard C. , Noel Jonathan A. 
Published: December 2014

AbstractThis work brings together ideas of mixing graph colorings, discrete homotopy, and precoloring extension. A particular focus is circular colorings. We prove that all the ‐colorings of a graph G can be obtained by successively recoloring a single vertex provided along the lines of Cereceda, van den Heuvel, and Johnson's result for k‐colorings. We give various bounds for such mixing results and discuss their sharpness, including cases where the bounds for circular and classical colorings coincide. As a corollary, we obtain an Albertson‐type extension theorem for ‐precolorings of circular cliques. Such a result was first conjectured by Albertson and West. General results on homomorphism mixing are presented, including a characterization of graphs G for which the endomorphism monoid can be generated through the mixing process. As in similar work of Brightwell and Winkler, the concept of dismantlability plays a key role.
Does diffusion‐weighted imaging improve therapy response evaluation in patients with hepatocellular carcinoma after radioembolization? comparison of MRI using Gd‐EOB‐DTPA with and without DWI
Authors: Schelhorn Juliane , Best Jan , Reinboldt Marcus P. , Dechêne Alexander , Gerken Guido , Ruhlmann Marcus , Lauenstein Thomas C. , Antoch Gerald , Kinner Sonja 
Published: December 2014

PurposeTo investigate whether additional diffusion‐weighted imaging (DWI) improves therapy response evaluation by Gd‐EOB magnetic resonance imaging (MRI) in hepatocellular carcinoma (HCC) after radioembolization.Materials and MethodsFifty patients with radioembolization for HCC underwent gadobutrol and Gd‐EOB MRI with DWI prior to and 30, 90, and 180 days after radioembolization. A combination of gadobutrol MRI, alpha‐fetoprotein, and imaging follow‐up served as the reference standard. Two radiologists reviewed Gd‐EOB alone (Gd‐EOB), DWI alone (DWI), and the combination of both (Gd‐EOB+DWI) separately and in consensus using a 4‐point‐scale: 1 = definitely no tumor progression (TP), 2 = probably no TP, 3 = probably TP, 4 = definitely TP. Receiver operating characteristic (ROC) and kappa analysis were performed.ResultsKappa values for Gd‐EOB, DWI, and Gd‐EOB+DWI ranged between 0.712 and 0.892 (P < 0.001). 30 days after radioembolization three out of 38 patients showed TP, which was missed by DWI in one case. No significant area under the curve (AUC) difference between Gd‐EOB (1.0, P = 0.004), DWI (0.881, P = 0.030), and Gd‐EOB+DWI (1.0, P = 0.004) was found (P = 0.320). 90 days after radioembolization six out of 28 patients showed TP, which was detected in one patient only by DWI and Gd‐EOB+DWI. The AUC did not differ significantly (P = 0.319) between Gd‐EOB (0.890, P = 0.004), DWI (1.0, P < 0.001), and Gd‐EOB+DWI (1.0, P < 0.001). 180 days after radioembolization five patients showed TP, which in one case was missed by DWI. The AUC did not differ significantly (P1 = 0.322, P2 = 0.369, P3 = 0.350) between Gd‐EOB (1.0, P = 0.003), DWI (0.913, P = 0.016), and Gd‐EOB+DWI (0.963, P = 0.007).ConclusionAdditional DWI does not substantially improve therapy response evaluation by Gd‐EOB MRI in HCC after radioembolization but proved helpful in single cases. J. Magn. Reson. Imaging 2015;42:818–827.
Comparative Rheological Characterization of Two Natural Polymers from Sesamum radiatum and Bombax buonopozense for Application in Drug Delivery
Authors: Ngwuluka Ndidi , Nep Elijah , Ochekpe Nelson , Odumosu Patricia , Olorunfemi Patrick 
Published: December 2014

SummarySmall deformation measurements have been used to characterize the rheological behaviour of two understudied natural polymers obtained from the leaves and calyxes of Sesamum radiatum and Bombax buonopozense respectively, by extraction with water, and then precipitation with absolute ethanol. Measurements performed on 1%w/v aqueous dispersion of each polymer at ambient conditions include viscosity, yield stress, oscillatory stress sweep, oscillatory frequency sweep, creep and recovery, and then temperature ramp. The measurements were done on the same samples on the first day and fourth day after storage at ambient temperature. The polymers exhibited shear‐ thinning with the viscosity of bombax gum remaining basically same on the 1st and 4th day while sesamum gum had a significant drop in viscosity by the 4th day. Bombax gum (yield value – 5.499 Pa at shear 0.114 s−1) had more internal strength than sesamum gum (yield value – 0.338 Pa at shear 0.032 s−1). In addition, bombax gum exhibited more elasticity and extended visco‐elastic region than sesamum gum. The present study suggests that bombax gum can be used for matrices and hydrogels with improved physicomechanical strength and sustained drug release while sesamum gum may require modification to achieve similar properties.
Micellization of Aminoterminated Poly(ethylene glycol)‐block‐poly(propylene glycol)‐block‐poly(ethylene glycol) in the Presence of Hyaluronic Acid
Authors: Neffe Axel T. , Santan Harshal D. , Kamlage Stefan , Gottschalk Benjamin , Lendlein Andreas 
Published: December 2014

SummaryAt concentrations above 15 wt‐%, aqueous solutions of mixtures of aminoterminated poly(ethylene glycol)‐block‐poly(propylene glycol)‐block‐poly(ethylene glycol) block copolymers (PEPE) and hyaluronic acid show a reversible sol‐gel‐transition upon change of temperature. For non‐aminoterminated PEPEs, this gel transition could be related to micellization and subsequent colloidal jamming of the micelles. Here, the mechanism of gelation for the aminoterminated compound is investigated by fluorescence spectroscopy and 1H‐NMR spectroscopy. The aminoterminated PEPE also form micelles. The onset of micellization is temperature and concentration dependent, and can be tuned to 20–40 °C. Interestingly, with increasing molecular weight of the hyaluronic acid component, the micellization is observed at lower concentrations.
Dynamic intravoxel incoherent motion imaging of skeletal muscle at rest and after exercise
Authors: Filli Lukas , Boss Andreas , Wurnig Moritz C. , Kenkel David , Andreisek Gustav , Guggenberger Roman 
Published: December 2014

The purpose of this work was to demonstrate the feasibility of intravoxel incoherent motion imaging (IVIM) for non‐invasive quantification of perfusion and diffusion effects in skeletal muscle at rest and following exercise.After IRB approval, eight healthy volunteers underwent diffusion‐weighted MRI of the forearm at 3 T and eight different b values between 0 and 500 s/mm2 with a temporal resolution of 57 s per dataset. Dynamic images were acquired before and after a standardized handgrip exercise. Diffusion (D) and pseudodiffusion (D*) coefficients as well as the perfusion fraction (FP) were measured in regions of interest in the flexor digitorum superficialis and profundus (FDS/FDP), brachioradialis, and extensor carpi radialis longus and brevis muscles by using a multi‐step bi‐exponential analysis in MATLAB. Parametrical maps were calculated voxel‐wise. Differences in D, D*, and FP between muscle groups and between time points were calculated using a repeated measures analysis of variance with post hoc Bonferroni tests.Mean values and standard deviations at rest were the following: D*, 28.5 ± 11.4 × 10−3 mm2/s; FP, 0.03 ± 0.01; D, 1.45 ± 0.09 × 10−3 mm2/s. Changes of IVIM parameters were clearly visible on the parametrical maps. In the FDS/FDP, D* increased by 289 ± 236% (p < 0.029), FP by 138 ± 58% (p < 0.01), and D by 17 ± 9% (p < 0.01). A significant increase of IVIM parameters could also be detected in the brachioradialis muscle, which however was significantly lower than in the FDS/FDP. After 20 min, all parameters were still significantly elevated in the FDS/FDP but not in the brachioradialis muscle compared with the resting state.The IVIM approach allows simultaneous quantification of muscle perfusion and diffusion effects at rest and following exercise. It may thus provide a useful alternative to other non‐invasive methods such as arterial spin labeling. Possible fields of interest for this technique include perfusion‐related muscle diseases, such as peripheral arterial occlusive disease. Copyright © 2014 John Wiley & Sons, Ltd.
Coalescence and break-up of nearly inviscid conical droplets
Authors: Bartlett Casey T. , Généro Guillaume A. , Bird James C. 
Published: December 2014

AbstractIn the presence of electric fields, pairs of liquid drops can be rapidly drawn together such that, at contact, the deformed interface resembles a double-cone. Following contact, these drop pairs are observed to either coalesce or recoil. Experimental and theoretical results suggest that the transition between coalescence and recoil is due to the conical drop topology rather than charge effects. However, even with this assumption, existing models disagree on how the transition develops, leading to different predictions of the critical cone angle and bridge morphology. Here we use high-resolution numerical simulations to highlight the impact of the initial double-cone angle on drop coalescence and reconcile the differences in the previous models. The results demonstrate a self-similar behaviour at intermediate scales for both coalescence and recoil that is independent of the other length scales in the problem. We calculate a critical polar angle of ${\it\theta}_{c}=1.14$ rad ($65.3^{\circ }$), or a complementary angle of ${\it\beta}=90^{\circ }-{\it\theta}_{c}=25^{\circ }$. This calculated critical angle for morphological transition is in agreement with previous experimental observations of ${\it\beta}\approx 27\pm 2^{\circ }$.
The rheology of non-dilute dispersions of highly deformable viscoelastic particles in Newtonian fluids
Authors: Avazmohammadi Reza , Ponte Castañeda Pedro 
Published: December 2014

AbstractWe present a model for the rheological behaviour of non-dilute suspensions of initially spherical viscoelastic particles in viscous fluids under uniform Stokes flow conditions. The particles are assumed to be neutrally buoyant Kelvin–Voigt solids undergoing time-dependent finite deformations and exhibiting generalized neo-Hookean behaviour in their purely elastic limit. We investigate the effects of the shape dynamics and constitutive properties of the viscoelastic particles on the macroscopic rheological behaviour of the suspensions. The proposed model makes use of known homogenization estimates for composite material systems consisting of random distributions of aligned ellipsoidal particles with prescribed two-point correlation functions to generate corresponding estimates for the instantaneous (incremental) response of the suspensions, together with appropriate evolution laws for the relevant microstructural variables. To illustrate the essential features of the model, we consider two special cases: (i) extensional flow and (ii) simple shear flow. For each case, we provide the time-dependent response and, when available, the steady-state solution for the average particle shape and orientation, as well as for the effective viscosity and normal stress differences in the suspensions. The results exhibit shear thickening for extensional flows and shear thinning for simple shear flows, and it is found that the volume fraction and constitutive properties of the particles significantly influence the rheology of the suspensions under both types of flows. In particular, for extensional flows, suspensions of particles with finite extensibility constraints are always found to reach a steady state, while this is only the case at sufficiently low strain rates for suspensions of (less realistic) neo-Hookean particles, as originally reported by Roscoe (J. Fluid Mech., vol. 28, 1967, pp. 273–293) and Gao et al. (J. Fluid Mech., vol. 687, 2011, pp. 209–237). For shear flows, viscoelastic particles with high viscosities can experience a damped oscillatory motion of decreasing amplitude before reaching the steady state.
ON DIFFERENCES BETWEEN THE BORDER RANK AND THE SMOOTHABLE RANK OF A POLYNOMIAL
Authors: BUCZYŃSKA WERONIKA , BUCZYŃSKI JAROSŁAW 
Published: December 2014

AbstractWe consider higher secant varieties to Veronese varieties. Most points on the rth secant variety are represented by a finite scheme of length r contained in the Veronese variety – in fact, for a general point, the scheme is just a union of r distinct points. A modern way to phrase it is: the smoothable rank is equal to the border rank for most polynomials. This property is very useful for studying secant varieties, especially, whenever the smoothable rank is equal to the border rank for all points of the secant variety in question. In this note, we investigate those special points for which the smoothable rank is not equal to the border rank. In particular, we show an explicit example of a cubic in five variables with border rank 5 and smoothable rank 6. We also prove that all cubics in at most four variables have the smoothable rank equal to the border rank.
LINEAR WEINGARTEN HYPERSURFACES WITH BOUNDED MEAN CURVATURE IN THE HYPERBOLIC SPACE
Authors: AQUINO CÍCERO P. , DE LIMA HENRIQUE F. , VELÁSQUEZ MARCO ANTONIO L. 
Published: December 2014

AbstractWe apply appropriate maximum principles in order to obtain characterization results concerning complete linear Weingarten hypersurfaces with bounded mean curvature in the hyperbolic space. By supposing a suitable restriction on the norm of the traceless part of the second fundamental form, we show that such a hypersurface must be either totally umbilical or isometric to a hyperbolic cylinder, when its scalar curvature is positive, or to a spherical cylinder, when its scalar curvature is negative. Related to the compact case, we also establish a rigidity result.
Establishment of a primed pluripotent epiblast stem cell in FGF4-based conditions
Authors: Joo Jin Young , Choi Hyun Woo , Kim Min Jung , Zaehres Holm , Tapia Natalia , Stehling Martin , Jung Koo Sung , Do Jeong Tae , Schöler Hans R. 
Published: December 2014

AbstractSeveral mouse pluripotent stem cell types have been established either from mouse blastocysts and epiblasts. Among these, embryonic stem cells (ESCs) are considered to represent a “naïve”, epiblast stem cells (EpiSCs) a “primed” pluripotent state. Although EpiSCs form derivatives of all three germ layers during invitro differentiation, they rarely incorporate into the inner cell mass of blastocysts and rarely contribute to chimera formation following blastocyst injection. Here we successfully established homogeneous population of EpiSC lines with efficient chimera-forming capability using a medium containing fibroblast growth factor (FGF)-4. The expression levels of Rex1 and Nanog was very low although Oct4 level is comparable to ESCs. EpiSCs also expressed higher levels of epiblast markers, such as Cer1, Eomes, Fgf5, Sox17 and T, and further showed complete DNA methylation of Stella and Dppa5 promoters. However, the EpiSCs were clustered separately from E3 and T9 EpiSC lines and showed a completely different global gene expression pattern to ESCs. Furthermore, the EpiSCs were able to differentiate into all three germ layers in vitro and efficiently formed teratomas and chimeric embryos (21.4%) without germ-line contribution.
Ab initio study of the RbSr electronic structure: Potential energy curves, transition dipole moments, and permanent electric dipole moments
Authors: Pototschnig Johann V. , Krois Günter , Lackner Florian , Ernst Wolfgang E. 
Published: December 2014

Excited states and the ground state of the diatomic molecule RbSr were calculated by post Hartree-Fock molecular orbital theory up to 22 000 cm−1. We applied a multireference configuration interaction calculation based on multiconfigurational self-consistent field wave functions. Both methods made use of effective core potentials and core polarization potentials. Potential energy curves, transition dipole moments, and permanent electric dipole moments were determined for RbSr and could be compared with other recent calculations. We found a good agreement with experimental spectra, which have been obtained recently by helium nanodroplet isolation spectroscopy. For the lowest two asymptotes (Rb (5s 2S) + Sr (5s4d 3P°) and Rb (5p 2P°) + Sr (5s2 1S)), which exhibit a significant spin-orbit coupling, we included relativistic effects by two approaches, one applying the Breit-Pauli Hamiltonian to the multireference configuration interaction wave functions, the other combining a spin-orbit Hamiltonian and multireference configuration interaction potential energy curves. Using the results for the relativistic potential energy curves that correspond to the Rb (5s 2S) + Sr (5s4d 3P°) asymptote, we have simulated dispersed fluorescence spectra as they were recently measured in our lab. The comparison with experimental data allows to benchmark both methods and demonstrate that spin-orbit coupling has to be included for the lowest states of RbSr.