Study of the plutino object (208996) 2003 AZ84 from stellar occultations: size, shape and topographic features

We present results derived from four stellar occultations by the plutino object (208996) 2003~AZ$_{84}$, detected at January 8, 2011 (single-chord event), February 3, 2012 (multi-chord), December 2, 2013 (single-chord) and November 15, 2014 (multi-chord). Our observations rule out an oblate spheroid solution for 2003~AZ$_{84}$'s shape. Instead, assuming hydrostatic equilibrium, we find that a Jacobi triaxial solution with semi axes $(470 \pm 20) \times (383 \pm 10) \times (245 \pm 8)$~km % axis ratios $b/a= 0.82 \pm 0.05$ and $c/a= 0.52 \pm 0.02$, can better account for all our occultation observations. Combining these dimensions with the rotation period of the body (6.75~h) and the amplitude of its rotation light curve, we derive a density $\rho=0.87 \pm 0.01$~g~cm$^{-3}$ a geometric albedo $p_V= 0.097 \pm 0.009$. A grazing chord observed during the 2014 occultation reveals a topographic feature along 2003~AZ$_{84}$'s limb, that can be interpreted as an abrupt chasm of width $\sim 23$~km and depth $> 8$~km or a smooth depression of width $\sim 80$~km and depth $\sim 13$~km (or an intermediate feature between those two extremes)

Binding and neutralization of vascular endothelial growth factor (VEGF) and related ligands by VEGF Trap, ranibizumab and bevacizumab

Pharmacological inhibition of VEGF-A has proven to be effective in inhibiting angiogenesis and vascular leak associated with cancers and various eye diseases. However, little information is currently available on the binding kinetics and relative biological activity of various VEGF inhibitors. Therefore, we have evaluated the binding kinetics of two anti-VEGF antibodies, ranibizumab and bevacizumab, and VEGF Trap (also known as aflibercept), a novel type of soluble decoy receptor, with substantially higher affinity than conventional soluble VEGF receptors. VEGF Trap bound to all isoforms of human VEGF-A tested with subpicomolar affinity. Ranibizumab and bevacizumab also bound human VEGF-A, but with markedly lower affinity. The association rate for VEGF Trap binding to VEGF-A was orders of magnitude faster than that measured for bevacizumab and ranibizumab. Similarly, in cell-based bioassays, VEGF Trap inhibited the activation of VEGFR1 and VEGFR2, as well as VEGF-A induced calcium mobilization and migration in human endothelial cells more potently than ranibizumab or bevacizumab. Only VEGF Trap bound human PlGF and VEGF-B, and inhibited VEGFR1 activation and HUVEC migration induced by PlGF. These data differentiate VEGF Trap from ranibizumab and bevacizumab in terms of its markedly higher affinity for VEGF-A, as well as its ability to bind VEGF-B and PlGF

Rational design of D-A1-D-A2 conjugated polymers with superior spectral coverage

The spectral coverage of a light-harvesting polymer largely determines the maximum achievable photocurrent in organic photovoltaics, and therefore constitutes a crucial parameter for improving their performance. The D-A1-D-A2 copolymer motif is a new and promising design strategy for extending the absorption range by incorporating two acceptor units with complementary photoresponses. The fundamental factors that promote an extended absorption are here determined for three prototype D-A1-D-A2 systems through a combination of experimental and computational methods. Systematic quantum chemical calculations are then used to reveal the intrinsic optical properties of ten further D-A1-D-A2 polymer candidates. These investigated polymers are all predicted to exhibit intense primary absorption peaks at 615-954 nm, corresponding to charge-transfer (CT) transitions to the stronger acceptor, as well as secondary absorption features at 444-647 nm that originate from CT transitions to the weaker acceptors. Realization of D-A1-D-A2 polymers with superior spectral coverage is thereby found to depend critically on the spatial and energetic separation between the two distinct acceptor LUMOs. Two promising D-A1-D-A2 copolymer candidates were finally selected for further theoretical and experimental study, and demonstrate superior light-harvesting properties in terms of significantly extended spectral coverage. This demonstrates great potential for enhanced light-harvesting in D-A1-D-A2 polymers via multiple absorption features compared to traditional D-A polymers

Light-harvesting capabilities of low band gap donor-acceptor polymers

A series of nine donor-acceptor polymers, including three new and six polymers from previous work, have been investigated experimentally and theoretically. The investigation focuses on narrow band gaps and strong absorptions of the polymers, where experimentally determined first peak absorption energies range from 1.8 to 2.3 eV, and peak absorption coefficients vary between 19-67 L g(-1) cm(-1). An overall assessment of each polymer's light-harvesting capability is made, and related to the chemical structure. Oligomer calculations using density functional theory are extrapolated to obtain size-converged polymer properties, and found to reproduce the experimental absorption trends well. Accurate theoretical predictions of absorption energies to within 0.06 eV of experiments, and absorption strength to within 12%, are obtained through the introduction of an empirical correction scheme. The computational and experimental results provide insight for the design of polymers with efficient absorption, concerning the intrinsic properties of the constituent units and the use of bulky side-groups

Temperature-Dependent Optical Properties of Flexible Donor - Acceptor Polymers

Optical properties of five donor acceptor polymers of interest for light-harvesting in organic photovoltaic devices have been studied experimentally and computationally. Experimentally recorded absorption spectra in solution of the five polymers are shown to be significantly temperature-dependent. The polymers were subjected to a first-principles computational treatment using density functional theory optimizations and excitation calculations. For two of the polymers, APFO-3 and PTI-1, a methodology that accounts for a thermally induced distribution of conformations based on Boltzmann statistics is applied to produce size- and temperature-converged optical results. This provides a deeper understanding of the temperature dependence of optical properties and improves the computational predictions of absorption wavelength and intensity at experimentally accessible temperatures, as compared to results from traditional quantum chemical calculations based on optimized polymers. Together, the combined experimental and computational temperature studies elucidate and quantify the significant influence of structural flexibility on the optical absorption properties of typical donor acceptor polymers

Ideologies of English in Shakespeare’s Henry V

This article examines the way in which the English language is conceptualized in Shakespeare’s Henry V, and the role this conceptualization plays in the portrayal of an emergent national identity. By analyzing how both the theme of language and the stylistic manipulation of language are foregrounded to effect the dramatic representation of cultural identity, the article considers the extent to which the play engages with early ideologies of linguistic nationalism, while also exploiting wider language ideological beliefs in its construction of character and dramatic narrative

Peripheral circadian clocks are diversely affected by adrenalectomy

<p>Glucocorticoids are considered to synchronize the rhythmicity of clock genes in peripheral tissues; however, the role of circadian variations of endogenous glucocorticoids is not well defined. In the present study, we examined whether peripheral circadian clocks were impaired by adrenalectomy. To achieve this, we tested the circadian rhythmicity of core clock genes (<i>Bmal1, Per1-3, Cry1, RevErbα, Rora</i>), clock-output genes (<i>Dbp, E4bp4</i>) and a glucocorticoid- and clock-controlled gene (<i>Gilz</i>) in liver, jejunum, kidney cortex, splenocytes and visceral adipose tissue (VAT). Adrenalectomy did not affect the phase of clock gene rhythms but distinctly modulated clock gene mRNA levels, and this effect was partially tissue-dependent. Adrenalectomy had a significant inhibitory effect on the level of <i>Per1</i> mRNA in VAT, liver and jejunum, but not in kidney and splenocytes. Similarly, adrenalectomy down-regulated mRNA levels of <i>Per2</i> in splenocytes and VAT, <i>Per3</i> in jejunum, <i>RevErbα</i> in VAT and <i>Dbp</i> in VAT, kidney and splenocytes, whereas the mRNA amounts of <i>Per1</i> and <i>Per2</i> in kidney and <i>Per3</i> in VAT and splenocytes were up-regulated. On the other hand, adrenalectomy had minimal effects on <i>Rora</i> and <i>E4bp4</i> mRNAs. Adrenalectomy also resulted in decreased level of <i>Gilz</i> mRNA but did not alter the phase of its diurnal rhythm. Collectively, these findings suggest that adrenalectomy alters the mRNA levels of core clock genes and clock-output genes in peripheral organs and may cause tissue-specific modulations of their circadian profiles, which are reflected in changes of the amplitudes but not phases. Thus, the circulating corticosteroids are necessary for maintaining the high-amplitude rhythmicity of the peripheral clocks in a tissue-specific manner.</p

High-Performance Hole Transport and Quasi-Balanced Ambipolar OFETs Based on D-A-A Thieno-benzo-isoindigo Polymers

Two new conjugated polymers are synthesized based on a novel donor-acceptor-acceptor (D-A-A) design strategy with the intention of attaining lower lowest unoccupied molecular obital levels compared to the normally used D-A strategy. By coupling two thieno-benzo-isoindigo units together via the phenyl position to give a new symmetric benzene-coupled di-thieno-benzo-isoindigo (BdiTBI) monomer as an A-A acceptor and thiophene (T) or bithiophene (2T) as a donor, two new polymers PT-BdiTBI and P2T-BdiTBI are synthesized via Stille coupling. The two polymers are tested in top gate and top contact field effect transistors, which exhibit balanced ambipolar charge transport properties with poly(methyl methacrylate) as dielectric and a high hole mobility up to 1.1 cm(2) V-1 s(-1) with poly(trifluoroethylene) as dielectric. The polymer films are investigated using atomic force microscopy, which shows fibrous features due to their high crystallinity as indicated by grazing incidence wide-angle X-ray scattering. The theoretical calculations agree well with the experimental data on the energy levels. It is demonstrated that the D-A-A strategy is very effective for designing low band gap polymers for organic electronic applications

Pyramid shape of polymer solar cells: a simple solution to triple efficiency

Pyramid-shaped polymer solar cells fabricated on flexible substrates were investigated. Effective light trapping can be realized due to light reflection in all 360 degrees directions, and 100% space utilization is achieved when assembled into arrays. The power conversion efficiency is enhanced by 200% ([60] PCBM as the acceptor) and 260% ([70] PCBM as the acceptor) with a dihedral angle of 30 degrees between the opposite sides of the pyramid compared with a planar device, and a high V-oc of 3.5 V in series connection is obtained. Considering the material utilization, an angle of 90 degrees for pyramid-shaped polymer solar cells is proposed. Pyramid-shaped polymer solar cells are particularly suitable for installation on roof of vehicles and houses, which have limited surface area