992 resultados para Driven 2-level Atoms


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Although the role of interleukin-2 (IL-2) and interferon gamma (gIFN) is still poorly understood in hyperthyroid diseases, it is reasonable to assume that these cytokines may be present at higher levels in Graves' disease (GD) than in other primarily non-autoimmune thyroid diseases. In order to look for an easy method to distinguish GD from primarily non-autoimmune causes of hyperthyroidism, we compared 13 healthy individuals with 21 treated and untreated hyperthyroid GD patients and with 19 patients with hyperthyroidism due to other etiologies: 7 cases of multinodular goiter, 5 cases of excessive hormone replacement and 7 cases of amiodarone-associated hyperthyroidism. All patients presented low TSH levels and a dubious clinical thyroid state. We found a good correlation between TSH and serum IL-2 levels (r = 0.56; P<0.01). Serum IL-2 (P<0.01) and gIFN (P<0.01) levels were lower in the hyperthyroid group of patients than in control subjects, suggesting a depressed TH1 pattern in the T-cell subset of hyperthyroid patients. GD had normal IL-2 levels, while patients with other forms of thyrotoxicosis presented decreased IL-2 levels (P<0.05). There was no difference between treated and untreated GD patients. We suggest that the direct measurement of serum IL-2 level may help to confirm hyperthyroidism caused by GD.

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Le motif imidazole, un hétérocycle à 5 atomes contenant 2 atomes d’azote et trois atomes de carbone, présente des propriétés physico-chimiques intéressantes qui en font un composé de choix pour plusieurs applications. Parmi ces propriétés, la fonctionnalisation simple des deux atomes d’azote pour former un sel d’imidazolium est très intéressante. Ces sels sont d’excellents précurseurs de carbènes N-hétérocycliques (NHC) et sont couramment utilisés pour synthétiser des ligands en vue d’une utilisation en catalyse organométallique. D’autre part, cette famille de composés possède des propriétés anionophores permettant une utilisation en transport anionique. Le présent travail contient les résultats de travaux concernant ces deux domaines, soit la catalyse et le transport anionique. Dans un premier temps, les propriétés de dérivés de l’imidazole sont exploitées pour former un catalyseur de type palladium-NHC qui est utilisé pour catalyser la réaction de Suzuki-Miyaura en milieu aqueux. L’efficacité de ce catalyseur a été démontrée en utilisant aussi peu que 0,001 mol% pour un rendement quantitatif. Il s’agit de la première occurrence d’un processus hétérogène et recyclable dans l’eau, utilisant un catalyseur de type Pd-NHC et qui ne nécessite aucun additif ou co-solvant. Le recyclage a été prouvé jusqu’à 10 cycles sans diminution apparente de l’activité du catalyseur. Dans un second temps, plusieurs sels d’imidazolium ont été testés en tant que transporteurs transmembranaires d’anions chlorures. Les propriétés intrinsèques des sels utilisés qui en font des transporteurs efficaces ont été élucidées. Ainsi, les paramètres qui semblent affecter le plus le transport anionique sont le changement du contre-anion du sel d’imidazolium de même que la propension de ce dernier à s’auto-assembler via une succession d’empilements-π. De plus, les propriétés du transport ont été élucidées, montrant la formation de canaux transmembranaires qui permettent non-seulement la diffusion d’ions Cl-, mais aussi le transport de protons et d’ions Ca2+. L’intérêt de cette recherche repose d’abord dans le traitement de diverses pathologies voyant leur origine dans le dysfonctionnement du transport anionique. Cependant, les propriétés bactéricides des sels d’imidazolium utilisés ont été identifiées lors des dernières expériences.

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Using a crossed-beam apparatus with a double hemispherical electron spectrometer, we have studied the spectrum of electrons released in thermal energy ionizing collisions of metastable He^*(2^3S) atoms with ground state Yb(4f^14 6s^2 ^1S_0) atoms, thereby providing the first Penning electron spectrum of an atomic target with-4f-electrons. In contrast to the HeI (58.4nm) and NeI (73.6/74.4nm) photoelectron spectra of Yb, which show mainly 4f- and 6s-electron emission in about a 5:1 ratio, the He^*(2^3S) Penning electron spectrum is dominated by 6s-ionization, acoompnnied by some correlation- induced 6p-emission (8% Yb+( 4f^14 6p^2P) formation) and very little 4f-ionization (<_~ 2.5%). This astounding result is attributed to the electron exchange mechanism for He^*(2^3S) ionization and reflects the poor overlap of the target 4f-electron wavefunction with the 1s-hole of He^*(2^3S), as discussed on thc basis of Dirac-Fock wave functions for the Yb orbitals and through calculations of the partial ionization cross sections involving semiempirical complex potentiale. The presented case may be regarded as the elearest atomic example for the surface sensitivity of He^*(2^3S) Penning ionization observed so far.

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In der gesamten Hochschullandschaft begleiten eLearning-Szenarien organisatorische Erneuerungsprozesse und stellen damit ein vielversprechendes Instrument zur Unterstützung und Verbesserung der klassischen Präsenzlehre dar. Davon ausgehend wurde von 2010 bis 2011 das Kasseler Sportspiel-Modell um die integrative Vermittlung der Einkontakt-Rückschlagspiele erweitert (Heyer, Albert, Scheid & Blömeke-Rumpf, 2011) und in einen modularisierten eLearning-Content, bestehend aus insgesamt 4 Modulen (17 Lernkurse, 171 Kursseiten, 73 Grafiken, 73 Videos, 38 Lernkontrollfragen), eingebunden. Dieser Content wurde im Rahmen einer Evaluationsstudie in Blended Learning Seminaren, welche die didaktischen Vorteile von Online- und Präsenzphasen zu einer Seminarform vereinen (Treumann, Ganguin & Arens, 2012), vergleichend zur klassischen Präsenzlehre im Sportstudium betrachtet. Die Studie gliedert sich in insgesamt drei Phasen: 1.) Pilotstudie am IfSS in Kassel (WS 2011/12; N=17, Lehramt), 2.) Hauptuntersuchung I am IfSS in Kassel (SS 2012; N=67, Lehramt) und 3.) Hauptuntersuchung II am IfS in Frankfurt a. M. (WS 2012/13; N=112, BA). Mittels varianzanalytischer Untersuchungsverfahren erfasst die Studie auf drei unterschiedlichen Qualitätsebenen folgende Aspekte der Lehr-Lernforschung: 1.) Ebene der Inputqualität: Bewertung der Seminarform (BS), 2.) Ebene der Prozessqualität: Motivation (SELLMO-ST), Lernstrategien (LIST) und computerbezogene Einstellung (FIDEC), 3.) Ebene der Outcomequalität: Lernleistung (Abschlusstest und Transferaufgabe). In der vergleichenden Betrachtung der beiden Hauptuntersuchungen erfolgt eine Gegenüberstellung von je einem Präsenzseminar zu zwei unterschiedlichen Varianten von Blended Learning Seminaren (BL-1, BL-2). Während der Online-Phasen bearbeiten die Sportstudierenden in BL-1 die Module in Lerngruppen. Die Teilnehmer in BL-2 führen in diesen Phasen zusätzlich persönliche Lerntagebücher. Dies soll zu einer vergleichsweise intensiveren Auseinandersetzung mit den Inhalten der Lernkurse sowie dem eigenen Lernprozess auf kognitiver und metakognitiver Ebene anregen (Hübner, Nückles & Renkl, 2007) und folglich zu besseren Ergebnissen auf den drei Qualitätsebenen führen. Die Ergebnisse der beiden Hauptuntersuchungen zeigen in der direkten, standortbezogenen Gegenüberstellung aller drei Seminarformen überwiegend keine statistisch signifikanten Unterschiede. Der erwartete positive Effekt durch die Einführung des Lerntagebuchs bleibt ebenfalls aus. Im standortübergreifenden Vergleich der Blended-Learning-Seminare ist bemerkenswert, dass die Probanden aus Frankfurt gegenüber ihrer Seminarform eine tendenziell kritischere Haltung einnehmen, was möglicherweise mit den vorherrschenden, unterschiedlichen Studiengängen – Lehramt und BA – korrespondiert. Zusammenfassend lässt sich somit für den untersuchten Bereich der Rückschlagspielvermittlung festhalten, dass Blended-Learning-Seminare eine qualitativ gleichwertige Alternative zur klassischen Präsenzlehre im Sportstudium darstellen.

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We analyse the widely-used international/ Zürich sunspot number record, R, with a view to quantifying a suspected calibration discontinuity around 1945 (which has been termed the “Waldmeier discontinuity” [Svalgaard, 2011]). We compare R against the composite sunspot group data from the Royal Greenwich Observatory (RGO) network and the Solar Optical Observing Network (SOON), using both the number of sunspot groups, N{sub}G{\sub}, and the total area of the sunspots, A{sub}G{\sub}. In addition, we compare R with the recently developed interdiurnal variability geomagnetic indices IDV and IDV(1d). In all four cases, linearity of the relationship with R is not assumed and care is taken to ensure that the relationship of each with R is the same before and after the putative calibration change. It is shown the probability that a correction is not needed is of order 10{sup}−8{\sup} and that R is indeed too low before 1945. The optimum correction to R for values before 1945 is found to be 11.6%, 11.7%, 10.3% and 7.9% using A{sub}G{\sub}, N{sub)G{\sub}, IDV, and IDV(1d), respectively. The optimum value obtained by combining the sunspot group data is 11.6% with an uncertainty range 8.1-14.8% at the 2σ level. The geomagnetic indices provide an independent yet less stringent test but do give values that fall within the 2σ uncertainty band with optimum values are slightly lower than from the sunspot group data. The probability of the correction needed being as large as 20%, as advocated by Svalgaard [2011], is shown to be 1.6 × 10{sup}−5{\sup}.

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The energy of the vh9/2 orbital in nuclei above N = 82 drops rapidly in energy relative to the vf7/2 orbital as the occupancy of the πh11/2 orbital increases. These two neutron orbitals become nearly degenerate as the proton drip line is approached. In this work, we have discovered the new nuclides 161Os and 157W, and studied the decays of the proton emitter 160Re in detail. The 161Os and 160Re nuclei were produced in reactions of 290, 300 and 310 MeV 58Ni ions with an isotopically enriched 106Cd target, separated in‐flight using the RITU separator and implanted into the GREAT spectrometer. The 161Os α a decays populated the new nuclide 157W, which decayed by β‐particle emission. The β decay fed the known α‐decaying 1/2+ and 11/2− states in 157Ta, which is consistent with a vf7/2 ground state in 157W. The measured α‐decay energy and half‐life for 161Os correspond to a reduced α‐decay width that is compatible with s‐wave α‐particle emission, implying that its ground state is also a vf7/2 state. Over 7000 160Re nuclei were produced and the γ decays of a new isomeric state feeding the πd3/2 level in 160Re were discovered, but no evidence for the proton or a decay of the expected πh11/2 state could be found. The isomer decays offer a natural explanation for this non‐observation and provides a striking example of the influence of the near degeneracy of the vh9/2 and vf7/2 orbitals on the properties of nuclei in this region.

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YAG phosphor powders doped/codoped with Er(3+)/(Er(3+) + Yb(3+)) have been synthesised by using the solution combustion method. The effect of direct pumping into the (4)I(11/2) level under 980 nm excitation of doped/codoped Er(3+)/Yb(3+)-Er(3+) in Y(3)Al(5)O(12) (YAG) phosphor responsible for an infrared (IR) emission peaking at similar to 1.53 mu m corresponding to the (4)I(13/2)->(4)I(15/2) transition has been studied. YAG exhibits three thermally-stimulated luminescence (TSL) peaks at around 140A degrees C, 210A degrees C and 445A degrees C. Electron spin resonance (ESR) studies were carried out to identify the centres responsible for the TSL peaks. The room temperature ESR spectrum of irradiated phosphor appears to be a superposition of two distinct centres. One of the centres (centre I) with principal g-value 2.0176 is identified as O(-) ion, while centre II with an isotropic g-factor 2.0020 is assigned to an F(+) centre (singly ionised oxygen vacancy). An additional defect centre is observed during thermal-annealing experiments and this centre (assigned to F(+) centre) seems to originate from an F-centre (oxygen vacancy with two electrons) and these two centres appear to correlate with the observed high-temperature TSL peak in YAG phosphor.

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Ce(0.8)SM(0.2)O(1.9) and CeO(2) nanomaterials were prepared by a solution technique to produce an ultrafine particulate material with high sinterability. In this work, the structural characteristics, the photoluminescent behavior and the ionic conductivity of the synthesized materials are focused. The thermally decomposed material consists of less than 10 nm in diameter nanoparticles. The Raman spectrum of pure CeO(2) consists of a single triple degenerate F(2g) model characteristic of the fluorite-like structure. The full width at half maximum of this band decreases linearly with increasing calcination temperature. The photoluminescence spectra show a broadened emission band assigned to the ligand-to-metal charge-transfer states O -> Ce(4+). The emission spectra of the Ce(0.8)Sm(0.2)O(1.9) specimens present narrow bands arising from the 4G(5/2) -> (6)H(J) transitions (J = 5/2, 7/2, 9/2 and 11/2) of Sm(3+) ion due to the efficient energy transfer from the O -> Ce(4+) transitions to the emitter 4G(5/2) level. The ionic conductivity of sintered specimens shows a significant dependence on density. (C) 2009 Elsevier B.V. All rights reserved.

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The photodynamic therapy (PDT) is a combination of using a photosensitizer agent, light and oxygen that can cause oxidative cellular damage. This technique is applied in several cases, including for microbial control. The most extensively studied light sources for this purpose are lasers and LED-based systems. Few studies treat alternative light sources based PDT. Sources which present flexibility, portability and economic advantages are of great interest. In this study, we evaluated the in vitro feasibility for the use of chemiluminescence as a PDT light source to induce Staphylococcus aureus reduction. The Photogem (R) concentration varied from 0 to 75 mu g/ml and the illumination time varied from 60 min to 240 min. The long exposure time was necessary due to the low irradiance achieved with chemiluminescence reaction at mu W/cm(2) level. The results demonstrated an effective microbial reduction of around 98% for the highest photosensitizer concentration and light dose. These data suggest the potential use of chemiluminescence as a light source for PDT microbial control, with advantages in terms of flexibility, when compared with conventional sources. (C) 2011 Elsevier B.V. All rights reserved.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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In this paper we investigate the energy transfer processes in TM3+/Er3+ doped telluride glass pumped at the commercial diode laser pump wavelength similar to 800 nm. Tailoring the rare-earths content in the glass matrix, seven main energy transfer channels within the doping range considered were identified, A 6-fold enhancement of the Er3+ visible frequency upconversion fluorescence at similar to 660 nm is observed due to the inclusion of Tm3+ ions. This is evidence of the relevant contribution of the route Er-1(I-4(11/2)) + Er-2(I-4(13/2)) -> Er-1(I-4(15/2)) + Er-2(F-4(9/2)) to the process. Energy migration among pumped I-4(9/2) level reducing the efficiency of the upconversion emission rate (H-3(11/2), S-4(3/2), and F-4(9/2)) is observed for Er3+ above 1.5 wt%. The rate equations regarding the observed energy transfer routes are determined and a qualitative analysis of the observed processes is reported. (c) 2006 Elsevier B.V. All rights reserved.

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Silica-based sol-gel waveguides activated by Er3+ ions are attractive materials for integrated optic devices. 70SiO(2)-30HfO(2) planar waveguides, doped with Er3+ concentrations ranging from 0.01 to 4 mol%, were prepared by sol-get route. The films were deposited on v-SiO2 and silica-on-silicon substrates, using dip-coating technique. The waveguides show a homogeneous surface morphology, high densification degree and uniform refractive index across the thickness. Emission in the C-telecommunication band was observed at room temperature for ill the samples upon excitation at 980 nm. The shape is found to be almost independent on erbium content, with a FWHM between 44 and 48 nm. The I-4(13/2) level decay curves presented a single-exponential profile, with a lifetime ranging between 1.1 and 6.7 ms, depending on the erbium concentration. The waveguide deposited on silica-on-silicon substrate supports one single propagation mode at 1.5 mum with a confinement coefficient of 0.85, and a losses of about 0.8 dB/cm at 632.8 nm. (C) 2003 Elsevier B.V. All rights reserved.