Der Übergang vom Elementar- zum Primarbereich. Erfahrungen estnischer und deutscher Eltern in der Covid-19-Pandemie

Das letzte Kindergartenjahr dient unter anderem der Vorbereitung auf die Grundschule. Die Bildungs- und Orientierungspläne für Kindertageseinrichtungen (im Folgenden Kita) weisen hierbei in Deutschland und Estland auf die Bedeutung einer intensiven Übergangsgestaltung hin. Aufgrund des durch die Covid-19-Pandemie ausgelösten Lockdowns im Schuljahr 2019/20 fanden in vielen europäischen Bildungseinrichtungen keine oder stark reduzierte Aktivitäten zur Übergangsgestaltung statt. In einer gemeinsamen explorativen Studie in Estland und Deutschland wurden im Juli und August 2020 Eltern, deren Kinder im Herbst eingeschult werden sollten (N = 52), nach ihren Erfahrungen, Befürchtungen und Wünschen in Zusammenhang mit dem Übergang von der Kita in die Grundschule unter Lockdown-Bedingungen befragt. (DIPF/Orig.

How present am I: three virtual reality facilities testing the fear of falling

Virtual reality environments have long been used in studies related to architecture simulation. The main objective of this paper is to measure the sense of presence that different virtual reality devices provide to users so as to evaluate their effectiveness when used to simulate real environments and draw conclusions of people’s behaviours when using them. The study also aims at investigating, in a quantitative way, the influence of architectural elements on the comfort of use of a built environment, namely considering the fear of falling reported by adults while using these architectural elements. Using a between-subjects design randomly distributed between two experimental conditions (safe and unsafe), a set of three studies were conducted in three different virtual reality environments using a 5-sided-CAVE, a Powerwall or a Head Mounted Display. The study shows that immersive virtual reality devices give users a higher sense of presence than semi-immersive ones. One of the conclusions of the study is that a higher sense of presence helps to enhance the building spaces perceived impacts on users (in this case the fear of falling).info:eu-repo/semantics/publishedVersio

Complexity and simplicity: tensions in teaching computation to large numbers of architecture students.

This paper describes the challenges and approaches to introduce computational thinking to a large and diverse group of architecture students during an international workshop with 300 students from different cultural backgrounds and educational levels, also integrating a diverse group of tutors whose computational expertise varied extremely. The approach suggested articulating a design task which enforced computational thinking but enabled different levels of engagement with the computer as a tool. Hypothetically this would allow all participants to engage with the computational thinking agenda regardless their computational affinity even whilst applying analogue methods. Besides the intercultural experience the workshop was successful in exposing a large group of students and tutors to the concepts of computational design whilst accommodating different learning preferences and engagement with the computer as a device

A regulatory calcium-binding site at the subunit interface of CLC-K kidney chloride channels

The two human CLC Cl− channels, ClC-Ka and ClC-Kb, are almost exclusively expressed in kidney and inner ear epithelia. Mutations in the genes coding for ClC-Kb and barttin, an essential CLC-K channel β subunit, lead to Bartter syndrome. We performed a biophysical analysis of the modulatory effect of extracellular Ca2+ and H+ on ClC-Ka and ClC-Kb in Xenopus oocytes. Currents increased with increasing [Ca2+]ext without full saturation up to 50 mM. However, in the absence of Ca2+, ClC-Ka currents were still 20% of currents in 10 mM [Ca2+]ext, demonstrating that Ca2+ is not strictly essential for opening. Vice versa, ClC-Ka and ClC-Kb were blocked by increasing [H+]ext with a practically complete block at pH 6. Ca2+ and H+ act as gating modifiers without changing the single-channel conductance. Dose–response analysis suggested that two protons are necessary to induce block with an apparent pK of ∼7.1. A simple four-state allosteric model described the modulation by Ca2+ assuming a 13-fold higher Ca2+ affinity of the open state compared with the closed state. The quantitative analysis suggested separate binding sites for Ca2+ and H+

Human ClC-6 Is a Late Endosomal Glycoprotein that Associates with Detergent-Resistant Lipid Domains

BACKGROUND: The mammalian CLC protein family comprises nine members (ClC-1 to -7 and ClC-Ka, -Kb) that function either as plasma membrane chloride channels or as intracellular chloride/proton antiporters, and that sustain a broad spectrum of cellular processes, such as membrane excitability, transepithelial transport, endocytosis and lysosomal degradation. In this study we focus on human ClC-6, which is structurally most related to the late endosomal/lysomal ClC-7. PRINCIPAL FINDINGS: Using a polyclonal affinity-purified antibody directed against a unique epitope in the ClC-6 COOH-terminal tail, we show that human ClC-6, when transfected in COS-1 cells, is N-glycosylated in a region that is evolutionary poorly conserved between mammalian CLC proteins and that is located between the predicted helices K and M. Three asparagine residues (N410, N422 and N432) have been defined by mutagenesis as acceptor sites for N-glycosylation, but only two of the three sites seem to be simultaneously N-glycosylated. In a differentiated human neuroblastoma cell line (SH-SY5Y), endogenous ClC-6 colocalizes with LAMP-1, a late endosomal/lysosomal marker, but not with early/recycling endosomal markers such as EEA-1 and transferrin receptor. In contrast, when transiently expressed in COS-1 or HeLa cells, human ClC-6 mainly overlaps with markers for early/recycling endosomes (transferrin receptor, EEA-1, Rab5, Rab4) and not with late endosomal/lysosomal markers (LAMP-1, Rab7). Analogously, overexpression of human ClC-6 in SH-SY5Y cells also leads to an early/recycling endosomal localization of the exogenously expressed ClC-6 protein. Finally, in transiently transfected COS-1 cells, ClC-6 copurifies with detergent-resistant membrane fractions, suggesting its partitioning in lipid rafts. Mutating a juxtamembrane string of basic amino acids (amino acids 71-75: KKGRR) disturbs the association with detergent-resistant membrane fractions and also affects the segregation of ClC-6 and ClC-7 when cotransfected in COS-1 cells. CONCLUSIONS: We conclude that human ClC-6 is an endosomal glycoprotein that partitions in detergent resistant lipid domains. The differential sorting of endogenous (late endosomal) versus overexpressed (early and recycling endosomal) ClC-6 is reminiscent of that of other late endosomal/lysosomal membrane proteins (e.g. LIMP II), and is consistent with a rate-limiting sorting step for ClC-6 between early endosomes and its final destination in late endosomes

Localization and function of the renal calcium-sensing receptor

The ability to monitor changes in the ionic composition of the extracellular environment is a crucial feature that has evolved in all living organisms. The cloning and characterization of the extracellular calcium-sensing receptor (CaSR) from the mammalian parathyroid gland in the early 1990s provided the first description of a cellular, ion-sensing mechanism. This finding demonstrated how cells can detect small, physiological variations in free ionized calcium (Ca 2+) in the extracellular fluid and subsequently evoke an appropriate biological response by altering the secretion of parathyroid hormone (PTH) that acts on PTH receptors expressed in target tissues, including the kidney, intestine, and bone. Aberrant Ca 2+ sensing by the parathyroid glands, as a result of altered CaSR expression or function, is associated with impaired divalent cation homeostasis. CaSR activators that mimic the effects of Ca 2+ (calcimimetics) have been designed to treat hyperparathyroidism, and CaSR antagonists (calcilytics) are in development for the treatment of hypercalciuric disorders. The kidney expresses a CaSR that might directly contribute to the regulation of many aspects of renal function in a PTH-independent manner. This Review discusses the roles of the renal CaSR and the potential impact of pharmacological modulation of the CaSR on renal function

Charakterisierung eines Oberflächenproteins Plasmodium falciparum infizierter Erythrozyten (PfEMP1_IT4_var16), welches die Bindung an verschiedene Endothelrezeptoren vermittelt

Die Plasmodium-Arten sind die Erreger der Malaria. Vor allem Plasmodium falciparum (P. falciparum) ist für die schweren Verläufe der Malaria verantwortlich. Dieser besitzt die Fähigkeit, einen von ihm infizierten Erythrozyten umzubauen und verschiedene Strukturen auszubilden. So werden auf der Oberfläche eines infizierten Erythrozyten knobs ausgebildet. In diesen knobs befinden sich spezielle Proteine aus der Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) -Familie, mit denen sich der infizierte Erythrozyt an Endothelzellen anhaften kann. Dies wird Zytoadhärenz genannt. Dabei kann es zu den schweren Symptomen der Malaria wie beispielsweise Organversagen oder der zerebralen Malaria kommen. Das geschieht, weil der Blutfluss in den kleinsten Blutgefäßen durch die Zytoadhärenz erheblich gestört werden kann. Die Zytoadhärenz ist eine Strategie des Parasiten, den Durchgang durch die Milz zu vermeiden. Dort würde dieser vom Immunsystem erkannt und zerstört werden. Über PfEMP1 erfolgt die Bindung an Endothelrezeptoren, die sich auf den Endothelzellen befinden. Für das Verständnis der Pathogenität von P. falciparum ist es von Wichtigkeit, diese Bindungen zwischen den PfEMP1-Proteinen und den Endothelrezeptoren zu charakterisieren. In dieser Arbeit wurde mit einer IT4-SLI-var16-Transfektante gearbeitet. Die Kultur einer solchen Transfektante exprimiert fast ausschließlich das var16-Gen. Die var-Gene kodieren für die unterschiedlichen PfEMP1s, von denen es pro Isolat etwa 60 verschiedene gibt. Normalerweise wechselt die Expression der var-Gene zu einem kleinen Teil nach jedem Durchlauf des asexuellen Lebenszyklus von P. falciparum. Mit der selection-linked integration-Methode (SLI) wird an das gewünschte var-Gen ein Resistenzgen über homologe Rekombination angefügt. Unter einem erzeugten Selektionsdruck können nur die Parasiten überleben, die das gewünschte var-Gen exprimieren. Es wurde die Bindung von var16_PfEMP1 an verschiedene Endothelrezeptoren in statischen Bindungs-Assays mit Hilfe von transgenen CHO-745-Zellen untersucht, die den jeweiligen Rezeptor auf ihrer Oberfläche präsentieren. Dabei wurden die Rezeptoren CD36, ICAM-1, TNFR2 und VCAM-1 als bekannte Bindungspartner von var16_PfEMP1 verifiziert. Für MDR1, EPCR, TNFR1, CD9, CD37 und CD81 konnte keine signifikante Bindung festgestellt werden. Ein neuer Bindungspartner mit CD55 wurde für var16_PfEMP1 gefunden. In einem Inhibitions-Assay wurde versucht, die Bindung zwischen var16_PfEMP1 und dem Endothelrezeptor ICAM-1 zu hemmen. Dazu wurde ein ICAM-1-Antikörper eingesetzt. Die Hemmung war jedoch nicht erfolgreich. Grund hierfür könnte sein, dass der eingesetzte Antikörper ein monoklonaler Antikörper war. Dieser bindet an nur ein Epitop von ICAM-1. Hier wäre für zukünftige Experimente ein polyklonaler Antikörper wahrscheinlich besser geeignet.Plasmodium species are the causative agents of malaria. Plasmodium falciparum (P. falciparum) in particular is responsible for the severe courses of malaria. The latter has the ability to remodel an erythrocyte infected by it and to form various structures. Knobs are formed on the surface of an infected erythrocyte. These knobs contain special proteins from the Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) family, which allows the infected erythrocyte to attach to endothelial cells. This process is called cytoadherence. It can lead to the severe symptoms of malaria such as organ failure or cerebral malaria. These symptoms appear as blood flow in the smallest blood vessels can be significantly disrupted by cytoadherence. Attachment to endothelial cells is a strategy of the parasite to avoid passing through the spleen, as it would be recognized and destroyed by the immune system. Via PfEMP1, binding occurs to endothelial receptors located on endothelial cells. To understand the pathogenicity of P. falciparum, it is important to characterize these bindings between PfEMP1 proteins and endothelial receptors. In this work, an IT4-SLI-var16 transfectant has been used. The culture of such a transfectant expresses almost exclusively the var16 gene. The var genes encode the different PfEMP1s, of which there are about 60 different ones per isolate. Usually, the expression of the var genes switches to a small extent after each run of the asexual life cycle of P. falciparum. Using the selection-linked integration method (SLI), a resistance gene is added to the desired var-gene via homologous recombination. Under a generated selection pressure, only parasites expressing the desired var-gene can survive. The binding of var16_PfEMP1 to different endothelial receptors has been investigated in static binding assays using transgenic CHO-745 cells presenting the respective receptor on their surface. The receptors CD36, ICAM-1, TNFR2, and VCAM-1 were verified as known binding partners of var16_PfEMP1. No significant binding was detected for MDR1, EPCR, TNFR1, CD9, CD37 and CD81. A new binding partner with CD55 has been found for var16_PfEMP1. An inhibition assay was performed in an attempt to inhibit binding between var16_PfEMP1 and the endothelial receptor ICAM-1. An ICAM-1 antibody has been used for this purpose. However, the inhibition was not successful. Using a monoclonal antibody could be the reason for this result. A polyclonal antibody would probably be more suitable for future experiments