Lead-free, luminescent perovskite nanocrystals obtained through ambient condition synthesis

Heterovalent substitution of toxic lead is an increasingly popular design strategy to obtain environmentally sustainable variants of the exciting material class of halide perovskites. Perovskite nanocrystals (NCs) obtained through solution-based methods exhibit exceedingly high optical quality. Unfortunately, most of these synthesis routes still require reaction under inert gas and at very high temperatures. Herein we present a novel synthesis routine for lead-free double perovskite NCs. We combine hot injection and ligand-assisted reprecipitation (LARP) methods to achieve a low-temperature and ambient atmosphere-based synthesis for manganese-doped Cs_{2}NaBiCl_{6} NCs. Mn incorporation is critical for the otherwise non-emissive material, with a 9:1 Bi:Mn precursor ratio maximizing the bright orange photoluminescence (PL) and quantum yield (QY). Higher temperatures slightly increased the material's performance, yet NCs synthesized at room temperature were still emissive, highlighting the versatility of the synthetic approach. Furthermore, the NCs show excellent long-term stability in ambient conditions, facilitating additional investigations and energy-related applications

Fine‐Tuning Blue‐Emitting Halide Perovskite Nanocrystals

Lead halide perovskite nanocrystals (NCs) with narrow, bright emission in the visible range are promising candidates for light-emitting applications. Near-unity quantum yields have been realized for green and red-emitting perovskites, but efficient, stable blue-emitting perovskite materials are scarce. Current methods to synthesize quantum-confined CsPbBr3 NCs with blue emission are limited to specific wavelength ranges and still suffer from inhomogeneously broadened emission profiles. Herein, anisotropic blue-green emitting CsPbBr3 NCs are synthesized in ambient atmosphere using a spontaneous crystallization method. Optical spectroscopy reveals a gradual, asymptotic photoluminescence (PL) redshift of pristine colloidal NCs after synthesis. During this process, the emission quality improves notably as the PL spectra become narrower and more symmetric, accompanied by a PL intensity increase. Electron microscopy indicates that the gradual redshift stems from an isotropic growth of the CsPbBr3 NCs in at least two dimensions, likely due to residual precursor ions in the dispersion. Most importantly, the growth process can be halted at any point by injecting an enhancement solution containing PbBr2 and organic capping ligands. Thus, excellent control over NC size is achieved, allowing for nanometer-precise tunability of the respective emission wavelength in the range between 475 and 500 nm, enhancing the functionality of these already impressive NCs

Neuausrichtungen und Handlungslogiken. Wissenschaftliche Begleitung der Modellprojekte im Themenfeld „Prävention und Deradikalisierung in Strafvollzug und Bewährungshilfe“ im Bundesprogramm „Demokratie leben!“ in der Förderphase 2020 bis 2024. Schwerpunktbericht 2020

Der vorliegende Schwerpunktbericht 2020 der wissenschaftlichen Begleitung beschreibt den Übergang der 15 im Themenfeld „Prävention und Deradikalisierung in Strafvollzug und Bewährungshilfe“ des Bundesprogramms „Demokratie leben!“ (2020–2024) geförderten Modellprojekte (MP) in die neue Programmphase. Er beleuchtet die durch die Covid-19-Pandemie verursachten Arbeitseinschränkungen und analysiert schwerpunktmäßig die Zielgruppenkonstruktionen, die der pädagogischen Arbeit zugrunde liegen sowie die pädagogischen Handlungsstrategien im Themenfeld. Die Grundlage bilden dabei insbesondere offene Interviews mit Vertreterinnen und Vertretern aller (Teil-)Modellprojekte. (DIPF/Orig.

Doubly stabilized perovskite nanocrystal luminescence downconverters

Halide perovskite nanocrystals (NCs) have emerged as a promising material for applications ranging from light-emitting diodes (LEDs) to solar cells and photodetectors. Still, several issues impede the realization of the nanocrystals' full potential, most notably their susceptibility to degradation from environmental stress. This work demonstrates highly stable perovskite nanocrystals (NCs) with quantum yields as high as 95 % by exploiting a ligand-assisted copolymer nanoreactor-based synthesis. The organic ligands thereby serve a dual function by enhancing the uptake of precursors and passivating the NCs. The polymer micelles and ligands thus form a double protection system, shielding the encapsulated NCs from water-, heat- and UV-light-induced degradation. We demonstrate the optoelectronic integrability by incorporating the perovskite NCs as spectrally pure downconverters on top of a deep-blue-emitting organic LED. These results establish a way of stabilizing perovskite NCs for optoelectronics while retaining their excellent optical properties

Associations between endogenous sex hormone levels and mammographic and bone densities in premenopausal women

PURPOSE: Mammographic breast and bone mineral densities (BMD) have been associated with luteal phase hormone concentrations in premenopausal women. We assessed the associations of breast and bone densities with follicular phase hormones and sex hormone binding globulin (SHBG) in premenopausal women given that follicular phase hormones have been shown to be positively associated with premenopausal breast cancer risk. METHODS: One hundred and ninety two 40-45 year old women provided a spot urine and/or blood sample during the follicular phase. Hormone and SHBG concentrations and bone density were measured and routine mammograms were accessed and digitized to obtain breast density measures. Regression models were fit to assess the associations between hormones and SHBG and breast and bone densities. RESULTS: Positive associations were observed between percent breast density and SHBG (p trend = 0.02), as well as estradiol (p trend = 0.08), after controlling for body mass index (BMI), number of pregnancies, and breast feeding history. In addition, a statistically significant inverse association was observed between total testosterone and head BMD (p trend = 0.01), after controlling for BMI. CONCLUSIONS: Associations were observed between breast and bone densities and serum hormone concentrations during the follicular phase of the menstrual cycle

From the northern ice shield to the Alpine glaciations

The route of the field trip described in this excursion guide follows a section through Germany from North to South, from the area of the Northern glaciation, to the Alpine glacial advances. It includes several places of historical importance, where milestones in Quaternary research have been achieved in the past, as well as new interesting sites where results of recent research is presented.excursionguid

Integrated Management of European Cherry Fruit Fly Rhagoletis cerasi (L.): Situation in Switzerland and Europe

Abstract: The European cherry fruit fly, Rhagoletis cerasi (L.) (Diptera: Tephritidae), is a highly destructive pest. The low tolerance for damaged fruit requires preventive insecticide treatments for a marketable crop. The phase-out of old insecticides threatens cherry production throughout the European Union (EU). Consequently, new management techniques and tools are needed. With the increasing number of dwarf tree orchards covered against rain to avoid fruit splitting, crop netting has become a viable, cost-effective method of cherry fruit fly control. Recently, a biocontrol method using the entomopathogenic fungus Beauveria bassiana has been developed for organic agriculture. However, for most situations, there is still a lack of efficient and environmentally sound insecticides to control this pest. This review summarizes the literature from over one hundred years of research on R. cerasi with focus on the biology and history of cherry fruit fly control as well as on antagonists and potential biocontrol organisms. We will present the situation of cherry fruit fly regulation in different European countries, give recommendations for cherry fruit fly control, show gaps in knowledge and identify future research opportunities

Cohort Profile: Antiretroviral Therapy Cohort Collaboration (ART-CC)

The advent of effective combination antiretroviral therapy (ART) in 1996 resulted in fewer patients experiencing clinical events, so that some prognostic analyses of individual cohort studies of human immunodeficiency virus-infected individuals had low statistical power. Because of this, the Antiretroviral Therapy Cohort Collaboration (ART-CC) of HIV cohort studies in Europe and North America was established in 2000, with the aim of studying the prognosis for clinical events in acquired immune deficiency syndrome (AIDS) and the mortality of adult patients treated for HIV-1 infection. In 2002, the ART-CC collected data on more than 12,000 patients in 13 cohorts who had begun combination ART between 1995 and 2001. Subsequent updates took place in 2004, 2006, 2008, and 2010. The ART-CC data base now includes data on more than 70 000 patients participating in 19 cohorts who began treatment before the end of 2009. Data are collected on patient demographics (e.g. sex, age, assumed transmission group, race/ethnicity, geographical origin), HIV biomarkers (e.g. CD4 cell count, plasma viral load of HIV-1), ART regimen, dates and types of AIDS events, and dates and causes of death. In recent years, additional data on co-infections such as hepatitis C; risk factors such as smoking, alcohol and drug use; non-HIV biomarkers such as haemoglobin and liver enzymes; and adherence to ART have been collected whenever available. The data remain the property of the contributing cohorts, whose representatives manage the ART-CC via the steering committee of the Collaboration. External collaboration is welcomed. Details of contacts are given on the ART-CC website (www.art-cohort-collaboration.org

Mythical numbers and the proceeds of organised crime: estimating mafia proceeds in Italy

Organised crime is a field vulnerable to mythical numbers, i.e. exaggerated estimates lacking empirical support, but acquiring acceptance through repetition. The figures on mafia proceeds in Italy are a striking example of this problem. This study proposes an estimation of mafia proceeds in Italy from nine criminal activities (sexual exploitation of women, illicit firearms trafficking, drug trafficking, counterfeiting, the illicit cigarette trade, illicit gambling, illicit waste disposal, loan sharking, and extortion racketeering) by region and type of mafia (Cosa Nostra, Camorra,\u2018Ndrangheta, Apulian mafias, and other mafias). The results estimate yearly mafia proceeds at approximately \u20ac10.7 bn (0.7% of the Italian GDP), discussing the impact on the regional and national economies and the differences among the types of mafias as to their geographical sources of revenue