104 research outputs found
Spontaneous Polarisation Build up in a Room Temperature Polariton Laser
We observe the build up of strong (~50%) spontaneous vector polarisation in
emission from a GaN-based polariton laser excited by short optical pulses at
room temperature. The Stokes vector of emitted light changes its orientation
randomly from one excitation pulse to another, so that the time-integrated
polarisation remains zero. This behaviour is completely different to any
previous laser. We interpret this observation in terms of the spontaneous
symmetry breaking in a Bose-Einstein condensate of exciton-polaritons
The effect of modafinil on the rat dopamine transporter and dopamine receptors D1âD3 paralleling cognitive enhancement in the radial arm maze
A series of drugs have been reported to increase memory performance modulating the dopaminergic system and herein modafinil was tested for its working memory (WM) enhancing properties. Reuptake inhibition of dopamine, serotonin (SERT) and norepinephrine (NET) by modafinil was tested. Sixty male SpragueâDawley rats were divided into six groups (modafinil-treated 1â5â10 mg/kg body weight, trained and untrained and vehicle treated trained and untrained rats; daily injected intraperitoneally for a period of 10 days) and tested in a radial arm maze (RAM), a paradigm for testing spatial WM. Hippocampi were taken 6 h following the last day of training and complexes containing the unphosphorylated or phosphorylated dopamine transporter (DAT-CC and pDAT-CC) and complexes containing the D1â3 dopamine receptor subunits (D1âD3-CC) were determined. Modafinil was binding to the DAT but insignificantly to SERT or NET and dopamine reuptake was blocked specifically (IC50 = 11.11 ÎŒM; SERT 1547 ÎŒM; NET 182 ÎŒM). From day 8 (day 9 for 1 mg/kg body weight) modafinil was decreasing WM errors (WMEs) in the RAM significantly and remarkably at all doses tested as compared to the vehicle controls. WMEs were linked to the D2R-CC and the pDAT-CC. pDAT and D1âD3-CC levels were modulated significantly and modafinil was shown to enhance spatial WM in the rat in a well-documented paradigm at all the three doses and dopamine reuptake inhibition with subsequent modulation of D1â3-CC is proposed as a possible mechanism of action. © 2015 Karabacak, Sase, Aher, Sase, Saroja, Cicvaric, Höger, Berger, Bakulev, Sitte, Leban, Monje and Lubec
G-arylated hydrogen-bonded cyclic tetramer assemblies with remarkable thermodynamic and kinetic stability
The preparation and self-assembly of novel G-C dinucleoside monomers that are equipped with electron-poor aryl groups at the G-N2 amino group have been studied. Such monomers associate via Watson-Crick H-bonding into discrete unstrained tetrameric macrocycles that arise as a thermodynamically and kinetically stabilized product in a wide variety of experimental conditions, including very polar solvent environments and low concentrations. G-arylation produces an increased stability of the cyclic assembly, as a result of a subtle interplay between enthalpic and entropic effects involving the solvent coordination sphereFunding from the European Research Council (ERC-StG 279548) and MINECO (CTQ2011-23659) is gratefully acknowledge
Deep inelastic inclusive and diffractive scattering at values from 25 to 320 GeV with the ZEUS forward plug calorimeter
Deep inelastic scattering and its diffractive component, , have been studied at HERA with the ZEUS
detector using an integrated luminosity of 52.4 pb. The method has
been used to extract the diffractive contribution. A wide range in the
centre-of-mass energy (37 -- 245 GeV), photon virtuality (20 -- 450
GeV) and mass (0.28 -- 35 GeV) is covered. The diffractive cross
section for GeV rises strongly with , the rise becoming
steeper as increases. The data are also presented in terms of the
diffractive structure function, , of the proton. For fixed
and fixed , \xpom F^{\rm D(3)}_2 shows a strong rise as \xpom \to
0, where \xpom is the fraction of the proton momentum carried by the
Pomeron. For Bjorken-, \xpom F^{\rm D(3)}_2 shows
positive scaling violations, while for
negative scaling violations are observed. The diffractive structure function is
compatible with being leading twist. The data show that Regge factorisation is
broken.Comment: 89 pages, 27 figure
High-Q^2 neutral current cross sections in e^+p deep inelastic scattering at sqrt{s}=318 GeV
Cross sections for e^+p neutral current deep inelastic scattering have been
measured at a centre-of-mass energy of sqrt{s}=318 GeV with the ZEUS detector
at HERA using an integrated luminosity of 63.2 pb^-1. The double-differential
cross section, d^2sigma/dxdQ^2, is presented for 200 GeV^2 < Q^2 < 30000 GeV^2
and for 0.005 < x < 0.65. The single-differential cross-sections dsigma/dQ^2,
dsigma/dx and dsigma/dy are presented for Q^2 > 200 GeV^2. The effect of
Z-boson exchange is seen in dsigma/dx measured for Q^2 > 10000 GeV^2. The data
presented here were combined with ZEUS e^+p neutral current data taken at
sqrt{s}=300 GeV and the structure function F_2^{em} was extracted. All results
agree well with the predictions of the Standard Model.Comment: Two references corrected. To be published in Physical Review
Solvent triggering between conformational states in amphiphilic shape-persistent macrocycles
The amphiphilic shape-persistent macrocycle 1 containing four phenol-OH groups as polar side groups and four hexyloxy groups as nonpolar side groups in an adaptable arrangement was recrystallized from solvents of different polarity. X-ray crystallography reveals that the conformation of the macrocycle is solvent dependent such that in the pyridine solvate only two of the nonpolar side groups point outward while in the THF solvate all four of them point outward. Moreover, in the latter case the three-dimensional packing leads to the formation of a supramolecular channel structure with a large pore size
A facile synthesis of large extraannular-functionalized phenyl- ethynyl macrocycles containing m-terphenyl units
[GRAPHICS] Two large extraannular-functionalized phenyl-ethynyl macrocycles; containing m-terphenyl units are described. The synthesis of the m-terphenyl building blocks is based on the transformation of pyryliurn salts to arenes
- âŠ