Optimizing infrared to near infrared upconversion quantum yield of β-NaYF₄:Er³⁺ in fluoropolymer matrix for photovoltaic devices

The present study reports for the first time the optimization of the infrared (1523 nm) to near-infrared (980 nm) upconversion quantum yield (UC-QY) of hexagonal trivalent erbium doped sodium yttrium fluoride (β-NaYF4:Er3+) in a perfluorocyclobutane (PFCB) host matrix under monochromatic excitation. Maximum internal and external UC-QYs of 8.4% ± 0.8% and 6.5% ± 0.7%, respectively, have been achieved for 1523 nm excitation of 970 ± 43 Wm−2 for an optimum Er3+ concentration of 25 mol% and a phosphor concentration of 84.9 w/w% in the matrix. These results correspond to normalized internal and external efficiencies of 0.86 ± 0.12 cm2 W−1 and 0.67 ± 0.10 cm2 W−1, respectively. These are the highest values ever reported for β-NaYF4:Er3+ under monochromatic excitation. The special characteristics of both the UC phosphor β-NaYF4:Er3+ and the PFCB matrix give rise to this outstanding property. Detailed power and time dependent luminescence measurements reveal energy transfer upconversion as the dominant UC mechanism

Extensive contemporary pollen-mediated gene flow in two herb species, Ranunculus bulbosus and Trifolium montanum, along an altitudinal gradient in a meadow landscape

Background and Aims Genetic connectivity between plant populations allows for exchange and dispersal of adaptive genes, which can facilitate plant population persistence particularly in rapidly changing environments. Methods Patterns of historic gene flow, flowering phenology and contemporary pollen flow were investigated in two common herbs, Ranunculus bulbosus and Trifolium montanum, along an altitudinal gradient of 1200-1800 m a.s.l. over a distance of 1 km among five alpine meadows in Switzerland. Key Results Historic gene flow was extensive, as revealed by Fst values of 0·01 and 0·007 in R. bulbosus and T. montanum, respectively, by similar levels of allelic richness among meadows and by the grouping of all individuals into one genetic cluster. Our data suggest contemporary pollen flow is not limited across altitudes in either species but is more pronounced in T. montanum, as indicated by the differential decay of among-sibships correlated paternity with increasing spatial distance. Flowering phenology among meadows was not a barrier to pollen flow in T. montanum, as the large overlap between meadow pairs was consistent with the extensive pollen flow. The smaller flowering overlap among R. bulbosus meadows might explain the slightly more limited pollen flow detected. Conclusions High levels of pollen flow among altitudes in both R. bulbosus and T. montanum should facilitate exchange of genes which may enhance adaptive responses to rapid climate chang

Antihyperon-Production in Relativistic Heavy Ion Collision

Recently it has been shown that the observed antiproton yield in heavy-ion collisions at CERN-SpS energies can be understood by multi-pionic interactions which enforce local chemical equilibrium of the antiprotons with the nucleons and pions. Here we show that antihyperons are driven towards local chemical equilibrium with pions, nucleons and kaons on a timescale of less than 3 fm/c when applying a similar argument for the antihyperons by considering the inverse channel of annihilation reactions anti-Y + p to pions + kaons. These multi-mesonic reactions easily explain the antihyperon yields at CERN-SpS energies as advertised in pure thermal, hadronic models without the need of a quark gluon plasma phase. In addition, the argument also applies for AGS energies.Comment: 4 pages using RevTeX, 1 eps figur

ARHGEF18/p114RhoGEF Coordinates PKA/CREB Signaling and Actomyosin Remodeling to Promote Trophoblast Cell-Cell Fusion During Placenta Morphogenesis

Coordination of cell-cell adhesion, actomyosin dynamics and gene expression is crucial for morphogenetic processes underlying tissue and organ development. Rho GTPases are main regulators of the cytoskeleton and adhesion. They are activated by guanine nucleotide exchange factors in a spatially and temporally controlled manner. However, the roles of these Rho GTPase activators during complex developmental processes are still poorly understood. ARHGEF18/p114RhoGEF is a tight junction-associated RhoA activator that forms complexes with myosin II, and regulates actomyosin contractility. Here we show that p114RhoGEF/ARHGEF18 is required for mouse syncytiotrophoblast differentiation and placenta development. In vitro and in vivo experiments identify that p114RhoGEF controls expression of AKAP12, a protein regulating protein kinase A (PKA) signaling, and is required for PKA-induced actomyosin remodeling, cAMP-responsive element binding protein (CREB)-driven gene expression of proteins required for trophoblast differentiation, and, hence, trophoblast cell-cell fusion. Our data thus indicate that p114RhoGEF links actomyosin dynamics and cell-cell junctions to PKA/CREB signaling, gene expression and cell-cell fusion

Retinoic Acid-Binding Protein in Human Breast Cancer and Dysplasia

Seventy-five specimens of human breast tissue were checked for the presence of cellular retinoic acid-binding protein (cRABP). Fifty-two percent of the primary carcinomas and 43% of the dysplastic breast lesions (stage MIl) contained detectable amounts of cRABP, whereas no cRABP was found in normal tissue. Sucrose gradient centrifugation and electrophoresis on agarose were used for analysis of the presence of cRABP. The cRABP of human origin (normal uterus and neoplastic mammary tissue) differed in its mobility in agarose electrophoresis from that of rat testis cRA

Asymmetric magnetic bubble expansion under in-plane field in Pt/Co/Pt: effect of interface engineering

We analyse the impact of growth conditions on asymmetric magnetic bubble expansion under in-plane field in ultrathin Pt / Co / Pt films. Specifically, using sputter deposition we vary the Ar pressure during the growth of the top Pt layer. This induces a large change in the interfacial structure as evidenced by a factor three change in the effective perpendicular magnetic anisotropy. Strikingly, a discrepancy between the current theory for domain-wall propagation based on a simple domain-wall energy density and our experimental results is found. This calls for further theoretical development of domain-wall creep under in-plane fields and varying structural asymmetry.Comment: 16 pages, 3 figure

Effects of acute and chronic hypohydration on tolerance to plus Gz acceleration in man. I - Physiological results

Effects of acute and chronic hypohydration on human physiological tolerance to gravity acceleratio

Die 'Sorge um sich' als Gegenkonzept zum Aktivitätsparadigma: Inklusions- und Exklusionspotentiale

Der Beitrag befasst sich mit der in den Altersdiskurs eingebrachten Formel der ‚Sorge um sich’ (Foucault) und thematisiert Übergänge zwischen 'drittem' und 'viertem' Alter sowie die damit verbundenen Ein- und Ausgrenzungen. Die ‚Sorge um sich‘ lässt sich zunächst positiv als Entlastung verstehen: In der Selbstsorge und in der Zuwendung zu sich selber können sich ältere Menschen den gesellschaftlichen Forderungen nach unablässiger Aktivität und dem gesellschaftlichen Druck der Nützlichkeit entziehen. Ein solches Selbstverhältnis, das nach Foucault immer auch eine gesellschaftliche Praxis meint und damit an der Pflicht gegenüber anderen orientiert ist, setzt bestimmte Spielräume voraus: in erster Linie Zeit, um sich mit sich selbst und mit anderen zu beschäftigen – also in reflexiver Selbstdistanz bewusst und selbstbestimmt zu leben. Alte Menschen verfügen in der Regel über Zeitressourcen. Sobald jedoch die Grenze zur Hochaltrigkeit erreicht wird, droht die Entlastung einer Sorge um sich in ihr Gegenteil umzuschlagen. Nun steht den nach wie vor grossen alltäglichen Zeitressourcen eine schwindende Lebenszeit gegenüber. Reflexionspotentiale erodieren im Prozess des körperlichen und geistigen ‚Verfalls’. Anstatt für sich selbst Sorge tragen zu können, setzt verstärkte Abhängigkeit ein. Der Beitrag stellt das normative Konzept einer ‚Sorge um sich‘ in seiner Ambivalenz theoretisch zur Diskussion und fragt nach der Grenzziehung zwischen einem inkludierten 'dritten' und einem exkludierten 'vierten' Alter sowie nach den entsprechenden sozialen Bezugsgruppen und deren Chancen auf Selbstsorge