Oxide phosphors for light upconversion; Yb3+ and Tm3+ co-doped Y2BaZnO5

Copyright 2011 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. This article appeared in Journal of Applied Physics 109, 063104 (2011) and may be found at

Metal oxides for efficient infrared to visible upconversion

Upconversion phosphor materials are attracting considerable attention for their possible applications in solar cells with improved efficiency, nanomaterials for bio-imaging, lasers and novel display technologies. Upconversion materials, usually consisting of crystals dopedwith lanthanide ions, can convert low-energy incident radiation into higher energy emittedradiation. Several mechanisms are involved, including multiple photon absorption and energy transfers between dopants. Up to now, reported upconversion efficiencies have beenrelatively low, excitation thresholds quite high, and the investigated phosphors (generally fluorides) often presented poor chemical stability (hygroscopy), limiting their industrial applicability. In this dissertation, we investigate the upconversion luminescence characteristics of rareearth-doped RE2BaZnO5 (RE = Y, Gd) phosphors, for near-infrared to visible upconversion. Being oxides, these materials have good chemical, thermal and mechanical properties. A variety of dopants, including Yb3+, Er3+, Ho3+ and Tm3+, were embedded in the host lattice, resulting in bright red, green, blue and white light emissions under 980 nm excitation and at relatively low excitation powers. Upconversion efficiencies up to ~ 5.2%, 2.6%, 1.7% and 0.3% were respectively achieved in samples doped with Yb3+, Er3+ (green and red emission), Yb3+, Ho3+ (green emission), Yb3+, Tm3+ (blue and near-infrared emission) and Yb3+, Er3+, Tm3+ (white light emission). We believe that our green, red and white emitting systems are the most efficient upconverting samples reported to date for green, red and whitelight emission, which makes them serious candidates for many of the applications listed above. The upconversion mechanisms were determined for the first time by means of indepth steady-state and time-resolved spectroscopic investigations, including concentration and power dependence studies associated with temperature-dependent lifetime measurements.EThOS - Electronic Theses Online ServiceSaint-Gobain Recherche, FranceGBUnited Kingdo

The impact of parent history of severe mental illness on schizophrenia outcomes: results from the real-world FACE-SZ cohort

International audienceParent history of severe mental illness (PHSMI) may have long-term consequences in adult offspring due to genetic and early environmental factors in preliminary studies. To compare the outcomes associated in subjects with PHSMI to those in patients without PHSMI. The participants with schizophrenia and schizoaffective disorders were recruited in the ongoing FACE-SZ cohort at a national level (10 expert centers) and evaluated with a 1-day-long standardized battery of clinician-rated scales and patient-reported outcomes. PHSMI was defined as history of schizophrenia or bipolar disorders in at least one parent and was included as explanatory variable in multivariate models. Of the 724 included patients, 78 (10.7%) subjects were classified in the PHSMI group. In multivariate analyses, PHSMI patients had a better insight into schizophrenia and the need for treatment and reported more often childhood trauma history compared to patients without PHSMI. More specifically, those with paternal history of SMI reported more severe outcomes (increased childhood physical and emotional abuses, comorbid major depression and psychiatric hospitalizations). PHSMI is associated with increased risk of childhood trauma, major depressive disorder and psychiatric hospitalization and better insight in individuals with schizophrenia. Specific public health prevention programs for parents with SMI should be developed to help protect children from pejorative psychiatric outcomes. PHSMI may also explain in part the association between better insight and increased depression in schizophrenia

Recommendations of the schizophrenia expert center network for the screening prevention and treatment of sleep disorders based on the results from the real-world schizophrenia FACE-SZ national cohort

Background: Sleep disorders associated factors are under explored in schizophrenia while the literature suggests high and heterogeneous frequency. Aims: The objective of the present study was to determine the prevalence and risk factors of sleep disorders in the real-world FACE-SZ national cohort. Method: Stabilized schizophrenic outpatients were recruited in 10 expert centers for schizophrenia. Sleep quality was explored with the Pittsburgh Sleep Quality Index (PSQI) and sleep disorders was defined by a PSQI score > 5. Psychosis severity was measured with the Positive and Negative Syndrome Scale, current major depressive episode with the Calgary Depression Scale for Schizophrenia, verbal aggressiveness with the Buss-Perry Aggression Questionnaire, adherence to treatment with the Medication Adherence Rating Scale, akathisia with the Barnes Akathisia Scale. Current somatic comorbidities and body mass index were reported. Variables with P values <0.20 in univariate analysis were included in a multivariate regression model. Results: Of the 562 included patients, 327 subjects (58.2%, IC95% [54.1% - 62.3%]) reported having sleep disorders. After adjustment, sleep disorders were significantly associated with migraine (adjusted odds ratio aOR = 2.23, p = 0.041), major depressive disorder (aOR 1.79, p = 0.030), poor adherence to treatment (aOR = 0.87, p = 0.006), akathisia (aOR = 1.29, p = 0.042) and verbal aggressiveness (aOR = 1.09, p = 0.002). Conclusions: More than one on two stabilized real-life outpatients with schizophrenia have been identified with sleep disorders. Combined with the literature data, we have yielded expert recommendations for the treatment and prevention of sleep disorders including treating undiagnosed comorbid depression and migraine and managing antipsychotic treatment to improve adherence and akathisia.Sorbonne Universités à Paris pour l'Enseignement et la RechercheFondaMental-Cohorte