Korrosionsuntersuchungen und Metallionenanalysen des Korrosionsmediums nach einem ISO-Normenentwurf für kieferorthopädische Brackets

Einleitung: Ein untoxisches Verhalten der kieferorthopädischen Werkstoffe sollte Voraussetzung für deren Verwendung in vivo sein. Bislang gibt es keine internationalen Grenzwerte für die Korrosionsbeständigkeit kieferorthopädischer Materialien.Material und Methode: In dieser Studie wurden zehn unterschiedliche Brackets verschiedener Hersteller, Systeme und Materialzusammensetzungen im Bezug auf Ihr Korrosionsverhalten untersucht. Hierzu wurde ein statischer Immersionstest in zwei verschiedenen Korrosionsmedien durchgeführt. Das jeweilige Medium wurde einer Metallionenanalyse der Elemente Chrom, Silizium, Mangan, Eisen, Kobalt, Nickel, Molybdän, Cadmium, Gold, Blei und Kupfer unterzogen und schließlich die Bracketoberfläche rasterelektronenmikroskopisch auf Korrosionsspuren hin untersucht. Der Versuchsaufbau entsprach dabei den Richtlinien der ISO-Norm 10271 für Korrosionsprüfverfahren für metallische Werkstoffe in der Zahnheilkunde.Ergebnis: Keines der untersuchten Brackets zeigte signifikante Korrosionsspuren nach Ablauf des statischen Immersionstest. Rasterelektronenmikroskopisch wurden keine Anzeichen für korrosive Prozesse festgestellt, die Ionenabgaben bewegten sich unterhalb des täglich mit der Nahrung aufgenommenen Durchschnittswerte.Zusammenfassung: Alle untersuchten Brackets scheinen biokompatibel und für den kieferorthopädischen Gebrauch einsetzbar zu sein

Not what u expect:Effects of prediction errors on item memory

The characterization of the relationship between predictions and one-shot episodic encoding poses an important challenge for memory research. On the one hand, events that are compatible with our previous knowledge are thought to be remembered better than incompatible ones. On the other hand, unexpected situations, by virtue of their novelty, are known to cause enhanced learning. Several theoretical accounts try to solve this apparent paradox by conceptualizing prediction error (PE) as a continuum ranging from low PE (for expectation-matching events) to high PE (for expectation-mismatching ones). Under such a framework, the relationship between PE and memory encoding would be described by a U-shape function with higher memory performance for extreme levels of PE and lower memory for middle levels of PE. In this study, we tested the framework by using a gradual manipulation of the strength of association between scenes and objects to render different levels of PE and then tested for item memory of the (mis)matching events. In two experiments, in contrast to what was anticipated, recognition memory for object identity followed an inverted U-shape as a function of PE, with higher performance for intermediate levels of PE. Furthermore, in two additional experiments, we showed the relevance of explicit predictions at encoding to reveal such an inverted U pattern, thus providing the boundary conditions of the effect. We discussed our findings in light of existing literature relating PE and episodic memory, pointing out the potential roles of uncertainty in the environment, and the importance of the cognitive operations underlying encoding tasks

The earliest thymic T cell progenitors sustain B cell and myeloid lineage potential

The stepwise commitment from hematopoietic stem cells in the bone marrow to T lymphocyte-restricted progenitors in the thymus represents a paradigm for understanding the requirement for distinct extrinsic cues during different stages of lineage restriction from multipotent to lineage-restricted progenitors. However, the commitment stage at which progenitors migrate from the bone marrow to the thymus remains unclear. Here we provide functional and molecular evidence at the single-cell level that the earliest progenitors in the neonatal thymus had combined granulocyte-monocyte, T lymphocyte and B lymphocyte lineage potential but not megakaryocyte-erythroid lineage potential. These potentials were identical to those of candidate thymus-seeding progenitors in the bone marrow, which were closely related at the molecular level. Our findings establish the distinct lineage-restriction stage at which the T cell lineage-commitment process transits from the bone marrow to the remote thymus. © 2012 Nature America, Inc. All rights reserved

Methylome Analysis and Epigenetic Changes Associated with Menarcheal Age

CAD received funding from EU-Europe aid grant CRIS 2009/223–507.The EPIC cohort is supported by the Europe Against Cancer Program of the European Commission (SANCO). The individual centres also received funding from: Denmark (Danish Cancer Society); France (Ligue centre le Cancer, Institut Gustave Roussy, Mutuelle Ge´ne´rale de l’Education Nationale, and Institut National de la Sante´ et de la Recherche Me´dicale (INSERM)); Greece (Hellenic Ministry of Health, the Stavros Niarchos Foundation and the Hellenic Health Foundation); Germany (German Cancer Aid, German Cancer Research Center, and Federal Ministry of Education and Research (Grant 01-EA-9401)); Italy (Italian Association for Research on Cancer and the National Research Council); The Netherlands (Dutch Ministry of Public Health, Welfare and Sports (VWS), Netherlands Cancer Registry (NKR), LK Research Funds, Dutch Prevention Funds, and Dutch ZON (Zorg Onderzoek Nederland), World Cancer Research Fund (WCRF)); Spain (Health Research Fund (FIS) of the Spanish Ministry of Health (Exp 96/0032) and the participating regional governments and institutions); Sweden (Swedish Cancer Society, Swedish Scientific Council, and Regional Government of Skane); and the United Kingdom (Cancer Research UK and Medical Research Council UK and Breast Cancer Campaign). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Rac1-Dependent Collective Cell Migration Is Required for Specification of the Anterior-Posterior Body Axis of the Mouse

Live imaging and analysis of conditional mutants show that the embryonic organizer that determines the anterior-posterior axis in the mouse embryo moves by Rac1-dependent collective cell migration

CropPol: a dynamic, open and global database on crop pollination

Seventy five percent of the world's food crops benefit from insect pollination. Hence, there has been increased interest in how global change drivers impact this critical ecosystem service. Because standardized data on crop pollination are rarely available, we are limited in our capacity to understand the variation in pollination benefits to crop yield, as well as to anticipate changes in this service, develop predictions, and inform management actions. Here, we present CropPol, a dynamic, open and global database on crop pollination. It contains measurements recorded from 202 crop studies, covering 3,394 field observations, 2,552 yield measurements (i.e. berry weight, number of fruits and kg per hectare, among others), and 47,752 insect records from 48 commercial crops distributed around the globe. CropPol comprises 32 of the 87 leading global crops and commodities that are pollinator dependent. Malus domestica is the most represented crop (32 studies), followed by Brassica napus (22 studies), Vaccinium corymbosum (13 studies), and Citrullus lanatus (12 studies). The most abundant pollinator guilds recorded are honey bees (34.22% counts), bumblebees (19.19%), flies other than Syrphidae and Bombyliidae (13.18%), other wild bees (13.13%), beetles (10.97%), Syrphidae (4.87%), and Bombyliidae (0.05%). Locations comprise 34 countries distributed among Europe (76 studies), Northern America (60), Latin America and the Caribbean (29), Asia (20), Oceania (10), and Africa (7). Sampling spans three decades and is concentrated on 2001-05 (21 studies), 2006-10 (40), 2011-15 (88), and 2016-20 (50). This is the most comprehensive open global data set on measurements of crop flower visitors, crop pollinators and pollination to date, and we encourage researchers to add more datasets to this database in the future. This data set is released for non-commercial use only. Credits should be given to this paper (i.e., proper citation), and the products generated with this database should be shared under the same license terms (CC BY-NC-SA). This article is protected by copyright. All rights reserved

Rainfall and the interaction of microclimate with larval resources in the population dynamics of checkerspot butterflies (Euphydryas editha) inhabiting serpentine grassland

International audienceThe interaction of host plant phenology and microclimatic heterogeneity was examined to determine its role in the population dynamics of checkerspot butterflies, Euphydryas editha, inhabiting serpentine grassland in California's outer Coast Range. Within the 2–3 hectares inhabited by a population of E. editha (Jasper Ridge Area H), microclimatic differences resulting from topographic heterogeneity largely determine the temporal and spatial pattern of senescence of the larval host plants, Plantago erecta and Orthocarpus densiflorus. Survival of larvae from hatching to diapause is extremely low as a result of unpredictable variation in the timing of larval development relative to the timing of host plant senescence, both of which are mediated by microclimatic patterns. During this study, population H declined to near extinction as a result of two consecutive years of record rainfall that apparently disrupted the tenuous temporal relationship between larval development and plant senescence. Retarded development of post-diapause larvae led to a late and extended flight season and delayed egg production; this in turn resulted in massive mortality of pre-diapause larvae due to starvation because host plant senescence occurred before larvae became large enough to enter diapause. Adult population size the following spring was the smallest in 25 years of study. This work emphasizes the importance of microclimatic heterogeneity for understanding population-level processes in small ectothermic animals and underlines the potential importance of such heterogeneity in the establishment of reserves designed to protect such animal

An Export-Specific Reporter Designed for Gram-Positive Bacteria: Application to Lactococcus lactis

The identification of exported proteins by fusion studies, while well developed for gram-negative bacteria, is limited for gram-positive bacteria, in part due to drawbacks of available export reporters. In this work, we demonstrate the export specificity and use of the Staphylococcus aureus secreted nuclease (Nuc) as a reporter for gram-positive bacteria. Nuc devoid of its export signal (called Δ(SP)Nuc) was used to create two fusions whose locations could be differentiated. Nuclease activity was shown to require an extracellular location in Lactococcus lactis, thus demonstrating the suitability of Δ(SP)Nuc to report protein export. The shuttle vector pFUN was designed to construct Δ(SP)Nuc translational fusions whose expression signals are provided by inserted DNA. The capacity of Δ(SP)Nuc to reveal and identify exported proteins was tested by generating an L. lactis genomic library in pFUN and by screening for Nuc activity directly in L. lactis. All Δ(SP)Nuc fusions displaying a strong Nuc(+) phenotype contained a classical or a lipoprotein-type signal peptide or single or multiple transmembrane stretches. The function of some of the predicted signals was confirmed by cell fractionation studies. The fusions analyzed included long (up to 455-amino-acid) segments of the exported proteins, all previously unknown in L. lactis. Homology searches indicate that several of them may be implicated in different cell surface functions, such as nutrient uptake, peptidoglycan assembly, environmental sensing, and protein folding. Our results with L. lactis show that Δ(SP)Nuc is well suited to report both protein export and membrane protein topology

Auf das richtige Maß kommt es an : wie beeinflussen digitale Medien unser Denken und Handeln?

Welchen Einfluss haben digitale Technologien auf das menschliche Wahrnehmen, Denken und Handeln? Schaden Computerspiele der Entwicklung junger Gehirne? Und gibt es tatsächlich so etwas wie eine »digitale Demenz«, eine durch die Nutzung moderner Technologien bedingte wachsende Vergesslichkeit? Auf einige dieser Fragen gibt es bereits Antworten, die empirisch belegt sind.What influence do digital technologies have on human perception, thinking and action? Do computer games harm the development of young brains? And is there really such a thing as »digital dementia«, an increasing forgetfulness caused by the use of modern technologies? For some of these questions, answers are available that are empirically corroborated

Auf das richtige Maß kommt es an : wie beeinflussen digitale Medien unser Denken und Handeln?

Welchen Einfluss haben digitale Technologien auf das menschliche Wahrnehmen, Denken und Handeln? Schaden Computerspiele der Entwicklung junger Gehirne? Und gibt es tatsächlich so etwas wie eine »digitale Demenz«, eine durch die Nutzung moderner Technologien bedingte wachsende Vergesslichkeit? Auf einige dieser Fragen gibt es bereits Antworten, die empirisch belegt sind.What influence do digital technologies have on human perception, thinking and action? Do computer games harm the development of young brains? And is there really such a thing as »digital dementia«, an increasing forgetfulness caused by the use of modern technologies? For some of these questions, answers are available that are empirically corroborated