18,099 research outputs found
Phase I/II trail of cultured autologous melanocytes and a new transplantation method for vitiligo treatment.
No full textElevated expression of Cyr61 enhances peritoneal dissemination of gastric cancer cells through integrin alpha2beta1.
No full textPhotoluminescence and excited states dynamics of Tm<sup>2+</sup>-doped CsCa(Cl/Br)<sub>3</sub> and CsCa(Br/I)<sub>3</sub> perovskites
Full text linkIn this study, we systematically vary the Cl/Br and Br/I ratios in CsCaX3:Tm2+ (X = Cl, Br, I) and hereby gradually shift the positions of the Tm2+ 4f125d1-levels as relative to the two 4f13 levels. At low temperatures up to five distinct Tm2+ 4f125d1→4f13 emissions and the 4f13→4f13 emission can be observed. As the temperature increases, most of the 4f125d1→4f13 emissions undergo quenching via multi-phonon relaxation (MPR) and at room temperature only the lowest energy 4f125d1→4f13 and the 4f13→4f13 emission remains. For all compositions a 4f13→4f13 risetime phenomenon is then observed whose duration matches the 4f125d1→4f13 decay time. It shows the feeding of the 4f13 state after 4f125d1 excitation. Surprisingly, the feeding time becomes longer from Cl→Br→I, while the related 4f125d1-4f13 energy gap becomes smaller. The temperature dependence of the 4f125d1→4f13 and 4f13→4f13 emission intensity shows a anticorrelation as earlier observed in other systems and confirms that the feeding process is thermally stimulated. However, the thermally stimulated activation energies that control the feeding process, increase from Cl→Br→I despite our observation that the 4f125d1-4f13 energy gap becomes smaller. An analysis reveals that the unexpected behaviour in risetime and activation energy, as a function of composition, cannot be explained by 4f125d1→4f13 feeding via interband crossing, but more likely via MPR where the electron–phonon coupling strength decreases from Cl→Br→I. No strong relation was found between composition and the quantum efficiency (QE) of the 4f13→4f13 emission, due to the presence of fluctuations that are likely caused by intrinsic differences in sample quality. Nevertheless, a 4f13→4f13 QE of up to 70% has been observed and the materials can therefore be used in luminescence solar concentrators.RST/Luminescence MaterialsChemE/O&O groe
The synthesis of monodisperse alkanes with long chains
Full text linkThis thesis discusses reasons for the interest in monodisperse long chain alkanes and describes attempts, past and present, to synthesise such molecules. Chapter 1 discusses why the synthesis of such molecules are important and the objectives of this project. Chapter 2 reviews the methods previous groups have devised to prepare pure samples of long chain alkanes. In particular, work carried out by Whiting et al. at Bristol, whose scheme formed the basis of the early work in Durham. Chapter 3 describes the work in Durham and improvements which were made to Whiting's method, allowing the synthesis of longer chain lengths and greater quantities of materials to be achieved. Chapter 4 provides a summary of the practical work carried out by the author. Chapter 5 gives experimental details of the work described in Chapter 4
Stromal-cell-derived factor-1{alpha} (SDF-1{alpha}/CXCL12)-enhanced angiogenesis of human basal cell carcinoma cells involves ERK1/2-NF-{kappa} B/interleukin-6 pathway.
No full textEffect of connective tissue growth factor on hypoxia-inducible factor 1alpha degradation and tumor angiogenesis.
No full textInvolvement of HIF-1α-dependent PAI-1 up-regulation in Cyr61/CCN1 induced gastric cancer cell invasion.
No full textAngular distribution of bromine atomic photofragment in oriented 2-bromobutane via hexapole state selector
No full textIn this work, an asymmetric top molecule 2-bromobutane has been successfully oriented by using hexapole state selector combined with orientation field, followed by detection of the bromine atomic photofragment distribution in the photolysis. The photofragment is produced in both the ground Br (2P3/2) and the excited Br (2P1/2) electronic states and both channels are studied by the slice imaging technique, revealing new features in the stereodynamic vectorial properties with respect to previous investigations on non-oriented molecules
Luminescent center in Br--rich BaFBr : O2-
No full textIn this work, emission, excitation and absorption spectra of pure and 1 mol% O2- -doped BaFxBr2 -x (x = 0.98, 1.0, 1.02) powders were measured. It was found that the spectra of O2- -doped Br--rich sample (x = 0.98) is different from those of the other O2--doped samples (x = 1.0 and 1.02). Its emission peak shifts from 500 to 550 nm, and becomes much wider. Absorption spectra show that F(Br-) centers of the X-rayed Br--rich sample, unlike those of other X-rayed samples, are not disturbed by doped oxygen. With the EPR, it is shown that O2- ions are on the F- sites in either F--rich(x = 1.02) or Br--rich sample. We suggested that in the Br--rich sample (x = 0.98) the luminescence is due to an O-F '-V-F(.) pair, instead of the O-F'-V-Br(.) pair in other samples (x = 1.0 and 1.02). (C) 1999 Elsevier Science B.V. All rights reserved.OpticsSCI(E)EI2ARTICLE3231-2358
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