Structural, electronic and optical properties of cadmium sulfide nanoparticles

In this work, the structural, electronic, and optical properties of CdS nanoparticles with sizes up to 4nm have been calculated using density-functional theory (DFT). Inaccuracies in the description of the unoccupied states of the applied density-functional based tight-binding method (DFTB) are overcome by a new SCF-DFTB method. Density-functional-based calculations employing linear-response theory have been performed on cadmium sulfide nanoparticles considering different stoichiometries, underlying crystal structures (zincblende, wurtzite, rocksalt), particle shapes (spherical, cuboctahedral, tetrahedral), and saturations (unsaturated, partly saturated, completely saturated). For saturated particles, the calculated onset excitations are strong excitonic. The quantum-confinement effect in the lowest excitation is visible as the excitation energy decreases towards the bulk band gap with increasing particle size. Dangling bonds at unsaturated surface atoms introduce trapped surface states which lie below the lowest excitations of the completely saturated particles. The molecular orbitals (MOs), that are participating in the excitonic excitations, show the shape of the angular momenta of a hydrogen atom (s, p). Zincblende- and wurtzite-derived particles show very similar spectra, whereas the spectra of rocksalt-derived particles are rather featureless. Particle shapes that confine the orbital wavefunctions strongly (tetrahedron) give rise to less pronounced spectra with lower oscillator strengths. Finally, a very good agreement of the calculated data to experimentally available spectra and excitation energies is found

Geophysical large-scale measurements in settlement chambers - measurement technique, data modeling and archaeological interpretation

Im Rahmen des DFG Projektes „Suzdal und Mohovoe/Wiskiauten - Prospektion und Erforschung frühmittelalterlicher Siedlungskammern im Kaliningrader Gebiet und in Westrussland“ wurden auf dem Fundplatz Mohovoe/Wiskiauten (Kaliningrader Oblast, Russland) großräumig geomag-netische Messungen zur Lokalisierung des Siedlungsplatzes durchgeführt. Die anschließende Schnellerkundung der dabei registrierten Anomalien mit einem Pürckhauer-Bohrer und die gezielte Ausgrabung einzelner Anomalien ließen allerdings erkennen, dass eine rein optische Interpretation der geophysikalischen Felddaten aus archäologischer Sicht schwierig und eine genauere Analyse von Nöten ist. In der vorliegenden Arbeit werden daher tiefergehende analytische Methoden entwickelt, die eine tatsächliche archäologisch relevante Interpretation von Geomagnetikdaten ermöglichen, und deren Ergebnisse in Bezug auf die in Mohovoe/Wiskiauten vorgenommenen Prospektionen und Grabungen vorgestellt. Darüber hinaus werden verschiedene Aspekte der Analysemöglichkeiten für die Fundplätze Suzdal in Russland, Apuolė und Kernavė in Litauen oder Grobiņa in Lettland vorgestellt. Eine automatisierte Detektion von Anomalien in den vorhandenen Geomagnetikdaten wurde verwirklicht durch Verwendung der zwei Funktionen Slope-Analyse und Fuzzy-Membership-Analyse der Software ArcGIS der Firma Esri. Während mit der Slopemethode vor allem Metall-gegenstände aus den Geomagnetikbildern herausgefiltert werden konnten, ermöglichte die Fuzzy-Membership-Methode die generelle Erkennung von geomagnetischen Anomalien im Bild. Eine anschließende statistische Analyse der gefundenen Anomalien zusammen mit der Betrachtung einer Kombination von archäologischen Vorabinformation, wie z. B. der Verteilung von Oberflächenfunden und Bohrergebnissen, ließ schließlich Rückschlüsse zu auf Fundplatz-grenzen sowie auf verschiedene Aktivitätsbereiche innerhalb der Fundplätze. Neben diesen Ergebnissen stellte sich aber auch heraus, dass unter Verwendung bereits erfasster und interpretierter Geomagnetikdaten auch weitere, noch unbekannte Anomalien zu einer hohen Wahrscheinlichkeit identifiziert und einer Kategorie zugewiesen werden können. Dies geschieht mithilfe einer Kreuzkorrelation und ist ein zusätzliches Resultat dieser Arbeit, welches für zukünftige archäologische Untersuchungen nicht außer acht gelassen werden sollte. Die in dieser Arbeit vorgestellten Methoden und Ergebnisse zeigen grundlegende Möglichkeiten, geophysikalische Prospektionsergebnisse über die optische Ansprache hinaus bei der Interpretation archäologischer Fundstellen miteinzubeziehen. Basierend auf den hier vorgestellten Ergebnissen lassen sich optimale Strategien zu einer effizienten Erkundung weiterer archäologisch relevanter Flächen ableiten.In the context of the DFG-Project “Suzdal and Mohovoe/Wiskiauten – geophysical prospection and comparison of data from Early Medieval settlements in the Kaliningrad area and in Western Russia” large-scale geomagnetic measurements have been carried out at the site of Mohovoe/Wiskiauten (Kaliningrad region, Russia) in order to locate the settlement area. The following exploration of the registered anomalies with a Pürckhauer-drilling equipment and the targeted excavation of single anomalies have indicated, that the optical interpretation of the geophysical field data from an archaeological point of view is difficult and a more precise analysis of the data is needed. In the present paper therefore in-depth analytical methods have been developed, that allow an effective archaeological relevant interpretation of geophysical data. The results are presented concerning the prospection and excavation data in Mohovoe/Wiskiauten. In addition the different aspects of interpreting the data are transferred to some other archaeological sites, i. e. Suzdal in Russia, Apuolė and Kernavė in Lithuania or Grobiņa in Latvia. An automated detection of anomalies within the geomagnetic data was realized by using the two functions slope-analysis and fuzzy-membership-analysis with help of the software ArcGIS from the firm Esri. While the slope-analysis above all made it possible to filter out metal objects, the fuzzy-membership-analysis allows the general detection of geomagnetic anomalies in the image. A following statistical analysis of the recognized anomalies combined with the archaeological information such as find contribution on the surface or drilling results helped to detect borders or different activity areas of the sites. Furthermore the mathematical analysis of the geophysical data in combination with the archaeological results allows the identification and interpretation of so far unexamined anomalies by using a cross correlation. The presented methods and results show basic possibilities of including geophysical prospection data into the interpretation of archaeological sites beyond the optical analysis. Based on the given results optimal strategies for an efficient prospection of further archaeological sites can be derived

Investigation of potential adverse central nervous system effects after long term oral administration of gadolinium in mice

Objectives: To examine potential gadolinium (Gd) accumulation in the brain of healthy mice after long-term oral administration of Gd-containing food pellets and to investigate whether Gd leads to adverse central nervous system (CNS) effects, specifically focussing on locomotor impairment in Gd exposed compared to control animals. Materials and methods: The local Animal Experimental Ethics Committee approved all procedures and applications. Fifteen female C57Bl/6 mice were orally exposed to a daily intake of 0.57 mmol Gd chloride/kg body weight over a period of 90 weeks from the age of 4 weeks on. Gd-free, but otherwise equivalent experimental diets were given to the control group (N = 13). The animals were monitored daily by animal caretakers regarding any visible signs of distress and evaluated clinically every four weeks for the first 60 weeks and afterwards every two weeks for a better temporal resolution of potential long-term effects regarding impairment of motor performance and loss of body weight. The individual Gd content was measured using mass spectrometry in a sub-cohort of N = 6 mice. Results The absolute brain Gd levels of the Gd-exposed mice were significantly increased compared to control mice (0.033 +/- 0.009 vs. 0.006 +/- 0.002 nmol Gd/g brain tissue). Long-term oral Gd exposure over almost the entire life-span did not lead to adverse CNS effects including locomotor changes (rotarod performance, p = 0.1467) in healthy mice throughout the study period. Gd-exposed mice showed less increased body weight compared to control mice during the study period (p = 0.0423). Histopathological alterations, such as hepatocellular vacuolization due to fatty change in the liver and a loss of nucleated cells in the red pulp of the spleen, were found in peripheral organs of both groups. Conclusions: Low levels of intracerebral Gd caused by chronic oral exposure over almost the entire life span of mice did not lead to alterations in locomotor abilities in healthy mice throughout the normal aging process

Methanol synthesis on ZnO(0001). III. Free energy landscapes, reaction pathways, and mechanistic insights

The interplay of physical and chemical processes in the heterogeneous catalytic synthesis of methanol on the ZnO(0001) surface with oxygen vacancies is expected to give rise to a complex free energy landscape. A manifold of intermediate species and reaction pathways has been proposed over the years for the reduction of CO on this catalyst at high temperature and pressure conditions as required in the industrial process. In the present study, the underlying complex reaction network from CO to methanol is generated in the first place by using ab initio metadynamics for computational heterogeneous catalysis. After having "synthesized" the previously discussed intermediates in addition to finding novel species, mechanistic insights into this network of surface chemical reactions are obtained based on exploring the global free energy landscape, which is refined by investigating individual reaction pathways. Furthermore, the impact of homolytic adsorption and desorption of hydrogen at the required reducing gas phase conditions is probed by studying such processes using different charge states of the F-center

Conceptual Frameworks and Methods for Advancing Invasion Ecology

Invasion ecology has much advanced since its early beginnings. Nevertheless, explanation, prediction, and management of biological invasions remain difficult. We argue that progress in invasion research can be accelerated by, first, pointing out difficulties this field is currently facing and, second, looking for measures to overcome them. We see basic and applied research in invasion ecology confronted with difficulties arising from (A) societal issues, e.g., disparate perceptions of invasive species; (B) the peculiarity of the invasion process, e.g., its complexity and context dependency; and (C) the scientific methodology, e.g., imprecise hypotheses. To overcome these difficulties, we propose three key measures: (1) a checklist for definitions to encourage explicit definitions; (2) implementation of a hierarchy of hypotheses (HoH), where general hypotheses branch into specific and precisely testable hypotheses; and (3) platforms for improved communication. These measures may significantly increase conceptual clarity and enhance communication, thus advancing invasion ecology

Ancient Plasmodium genomes shed light on the history of human malaria

Malaria-causing protozoa of the genus Plasmodium have exerted one of the strongest selective pressures on the human genome, and resistance alleles provide biomolecular footprints that outline the historical reach of these species1. Nevertheless, debate persists over when and how malaria parasites emerged as human pathogens and spread around the globe1,2. To address these questions, we generated high-coverage ancient mitochondrial and nuclear genome-wide data from P. falciparum, P. vivax and P. malariae from 16 countries spanning around 5,500 years of human history. We identified P. vivax and P. falciparum across geographically disparate regions of Eurasia from as early as the fourth and first millennia bce, respectively; for P. vivax, this evidence pre-dates textual references by several millennia3. Genomic analysis supports distinct disease histories for P. falciparum and P. vivax in the Americas: similarities between now-eliminated European and peri-contact South American strains indicate that European colonizers were the source of American P. vivax, whereas the trans-Atlantic slave trade probably introduced P. falciparum into the Americas. Our data underscore the role of cross-cultural contacts in the dissemination of malaria, laying the biomolecular foundation for future palaeo-epidemiological research into the impact of Plasmodium parasites on human history. Finally, our unexpected discovery of P. falciparum in the high-altitude Himalayas provides a rare case study in which individual mobility can be inferred from infection status, adding to our knowledge of cross-cultural connectivity in the region nearly three millennia ago.This project was funded by the National Science Foundation, grants BCS-2141896 and BCS-1528698; the European Research Council (ERC) under the European Union’s Horizon 2020 programme, grants 851511-MICROSCOPE (to S. Schiffels), 771234-PALEoRIDER (to W.H.) and starting grant 805268-CoDisEASe (to K.I.B.); and the ERC starting grant Waves ERC758967 (supporting K. Nägele and S.C.). We thank the Max Planck-Harvard Research Center for the Archaeoscience of the Ancient Mediterranean for supporting M. Michel, E. Skourtanioti, A.M., R.A.B., L.C.B., G.U.N., N.S., V.V.-M., M. McCormick, P.W.S., C.W. and J.K.; the Kone Foundation for supporting E.K.G. and A.S.; and the Faculty of Medicine and the Faculty of Biological and Environmental Sciences at the University of Helsinki for grants to E.K.G. A.S. thanks the Magnus Ehrnrooth Foundation, the Sigrid Jusélius Foundation, the Finnish Cultural Foundation, the Academy of Finland, the Life and Health Medical Foundation and the Finnish Society of Sciences and Letters. M.C.B. acknowledges funding from: research project PID2020-116196GB-I00 funded by MCIN/AEI/10.13039/501100011033; the Spanish Ministry of Culture; the Chiang Ching Kuo Foundation; Fundación Palarq; the EU FP7 Marie Curie Zukunftskolleg Incoming Fellowship Programme, University of Konstanz (grant 291784); STAR2-Santander Universidades and Ministry of Education, Culture and Sports; and CEI 2015 project Cantabria Campus Internacional. M.E. received support from the Czech Academy of Sciences award Praemium Academiae and project RVO 67985912 of the Institute of Archaeology of the Czech Academy of Sciences, Prague. This work has been funded within project PID2020-115956GB-I00 ‘Origen y conformación del Bronce Valenciano’, granted by the Ministry of Science and Innovation of the Government of Spain, and grants from the Canadian Institutes for Health Research (MZI187236), Research Nova Scotia (RNS 2023-2565) and The Center for Health Research in Developing Countries. D.K. is the Canada research chair in translational vaccinology and inflammation. R.L.K. acknowledges support from a 2019 University of Otago research grant (Human health and adaptation along Silk Roads, a bioarchaeological investigation of a medieval Uzbek cemetery). P.O. thanks the Jane and Aatos Erkko Foundation, the Finnish Cultural Foundation and the Academy of Finland. S. Peltola received support from the Emil Aaltonen Foundation and the Ella and Georg Ehrnrooth Foundation. D.C.S.-G. thanks the Generalitat Valenciana (CIDEGENT/2019/061). E.W.K. acknowledges support from the DEEPDEAD project, HERA-UP, CRP (15.055) and the Horizon 2020 programme (grant 649307). M. Spyrou thanks the Elite program for postdocs of the Baden-Württemberg Stiftung. Open access funding provided by Max Planck Society

Early mobilisation in critically ill COVID-19 patients: a subanalysis of the ESICM-initiated UNITE-COVID observational study

Background Early mobilisation (EM) is an intervention that may improve the outcome of critically ill patients. There is limited data on EM in COVID-19 patients and its use during the first pandemic wave. Methods This is a pre-planned subanalysis of the ESICM UNITE-COVID, an international multicenter observational study involving critically ill COVID-19 patients in the ICU between February 15th and May 15th, 2020. We analysed variables associated with the initiation of EM (within 72 h of ICU admission) and explored the impact of EM on mortality, ICU and hospital length of stay, as well as discharge location. Statistical analyses were done using (generalised) linear mixed-effect models and ANOVAs. Results Mobilisation data from 4190 patients from 280 ICUs in 45 countries were analysed. 1114 (26.6%) of these patients received mobilisation within 72 h after ICU admission; 3076 (73.4%) did not. In our analysis of factors associated with EM, mechanical ventilation at admission (OR 0.29; 95% CI 0.25, 0.35; p = 0.001), higher age (OR 0.99; 95% CI 0.98, 1.00; p ≤ 0.001), pre-existing asthma (OR 0.84; 95% CI 0.73, 0.98; p = 0.028), and pre-existing kidney disease (OR 0.84; 95% CI 0.71, 0.99; p = 0.036) were negatively associated with the initiation of EM. EM was associated with a higher chance of being discharged home (OR 1.31; 95% CI 1.08, 1.58; p = 0.007) but was not associated with length of stay in ICU (adj. difference 0.91 days; 95% CI − 0.47, 1.37, p = 0.34) and hospital (adj. difference 1.4 days; 95% CI − 0.62, 2.35, p = 0.24) or mortality (OR 0.88; 95% CI 0.7, 1.09, p = 0.24) when adjusted for covariates. Conclusions Our findings demonstrate that a quarter of COVID-19 patients received EM. There was no association found between EM in COVID-19 patients' ICU and hospital length of stay or mortality. However, EM in COVID-19 patients was associated with increased odds of being discharged home rather than to a care facility. Trial registration ClinicalTrials.gov: NCT04836065 (retrospectively registered April 8th 2021)