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DNA origami nanostructures allow for the arrangement of different functionalities such as proteins, specific DNA structures, nanoparticles, and various chemical modifications with unprecedented precision. The arranged functional entities can be visualized by atomic force microscopy (AFM) which enables the study of molecular processes at a single-molecular level. Examples comprise the investigation of chemical reactions, electron-induced bond breaking, enzymatic binding and cleavage events, and conformational transitions in DNA. In this paper, we provide an overview of the advances achieved in the field of single-molecule investigations by applying atomic force microscopy to functionalized DNA origami substrates.
Eye movements depend on cognitive processes related to visual information processing. Much has been learned about the spatial selection of fixation locations, while the principles governing the temporal control (fixation durations) are less clear. Here, we review current theories for the control of fixation durations in tasks like visual search, scanning, scene perception, and reading and propose a new model for the control of fixation durations. We distinguish two local principles from one global principle of control. First, an autonomous saccade timer initiates saccades after random time intervals (local-I). Second, foveal inhibition permits immediate prolongation of fixation durations by ongoing processing (local-II). Third, saccade timing is adaptive, so that the mean timer value depends on task requirements and fixation history (Global). We demonstrate by numerical simulations that our model qualitatively reproduces patterns of mean fixation durations and fixation duration distributions observed in typical experiments. When combined with assumptions of saccade target selection and oculomotor control, the model accounts for both temporal and spatial aspects of eye movement control in two versions of a visual search task. We conclude that the model provides a promising framework for the control of fixation durations in saccadic tasks.
Rezensierte Werke: Lintl, P., Fundamentalismus – Messianismus – Nationalismus. Ein Theorievergleich am Beispiel der jüdischen Siedler des Westjordanlandes. - Hamburg: Diplomica 2012. - 245 S. ISBN 978-3-8428-8663-6 Inbari, M., Messianic Religious Zionism Confronts Israeli Territorial Compromises. - Cambridge: Cambridge University Press 2012. - 211 S.
Dendritic cells (DCs) are the cutting edge in innate and adaptive immunity. The major functions of these antigen presenting cells are the capture, endosomal processing and presentation of antigens, providing them an exclusive ability to provoke adaptive immune responses and to induce and control tolerance. Immature DCs capture and process antigens, migrate towards secondary lymphoid organs where they present antigens to naive T cells in a well synchronized sequence of procedures referred to as maturation. Indeed, recent research indicated that sphingolipids are modulators of essential steps in DC homeostasis. It has been recognized that sphingolipids not only modulate the development of DC subtypes from precursor cells but also influence functional activities of DCs such as antigen capture, and cytokine profiling. Thus, it is not astonishing that sphingolipids and sphingolipid metabolism play a substantial role in inflammatory diseases that are modulated by DCs. Here we highlight the function of sphingosine 1-phosphate (S1P) on DC homeostasis and the role of SIP and SW metabolism in inflammatory diseases.
Insulin resistance is a complex metabolic disorder in which insulin-sensitive tissues fail to respond to the physiological action of insulin. There is a strong correlation of insulin resistance and the development of type 2 diabetes both reaching epidemic proportions. Dysfunctional lipid metabolism is a hallmark of insulin resistance and a risk factor for several cardiovascular and metabolic disorders. Numerous studies in humans and rodents have shown that insulin resistance is associated with elevations of non-esterified fatty acids (NEFA) in the plasma. Moreover, bioactive lipid intermediates such as diacylglycerol (DAG) and ceramides appear to accumulate in response to NEFA, which may interact with insulin signaling. However, recent work has also indicated that sphingosine 1-phosphate (S1P), a breakdown product of ceramide, modulate insulin signaling in different cell types. In this review, we summarize the current state of knowledge about S1P and insulin signaling in insulin sensitive cells. A specific focus is put on the action of S1P on hepatocytes, pancreatic beta-cells and skeletal muscle cells. In particular, modulation of S1P-signaling can be considered as a potential therapeutic target for the treatment of insulin resistance and type 2 diabetes.
Rezensierte Werke: Lohmann, U.: David Friedländer. Reformpolitik im Zeichen von Aufklärung und Emanzipation. Kontexte des preußischen Judenedikts vom 11. März 1812. - Hannover: Wehrhahn 2013. - 576 S. ISBN 978-3-86525-310-1 David Friedländer: Ausgewählte Werke. Herausgegeben von Uta Lohmann. (= Deutsch-jüdische Autoren des 19. Jahrhunderts. Schriften zu Staat, Nation, Gesellschaft. Werkausgaben, Bd. 4). - Köln–Wien: Böhlau 2013. - 322 S. ISBN 978-3-412-20938-4
Rezensierte Werke: Kiwitt, M.: Les gloses françaises du glossaire biblique B.N. hébr. 301. Édition critique partielle et étude linguistique (= Romanische Texte des Mittelalters, Bd. 2). - Heidelberg: Universitätsverlag Winter 2013. - 472 S. Edzard, A.B.: Varietätenlinguistische Untersuchungen zum Judenfranzösischen (= Bonner Romanistische Arbeiten, Bd. 103). - Bern–Berlin–Frankfurt am Main.: Peter Lang 2011. - 398 S. ISBN 978-3-631-61571-3
Resurrection species are a group of land plants that can tolerate extreme desiccation of their vegetative tissues during harsh drought stress, and still quickly often within hours regain normal physiological and metabolic functions following rehydration. At the molecular level, this desiccation tolerance is attributed to basal cellular mechanisms including the constitutive expression of stress-associated genes and high levels of protective metabolites present already in the absence of stress, as well as to transcriptome and metabolome reconfigurations rapidly occurring during the initial phases of drought stress. Parts of this response are conferred by unique metabolites, including a diverse array of sugars, phenolic compounds, and polyols, some of which accumulate to high concentrations within the plant cell. In addition to drought stress, these metabolites are proposed to contribute to the protection against other abiotic stresses and to an increased oxidative stress tolerance. Recently, extracts of resurrection species and particular secondary metabolites therein were reported to display biological activities of importance to medicine, with e.g. antibacterial, anticancer, antifungal, and antiviral activities, rendering them possible candidates for the development of novel drug substances as well as for cosmetics. Herein, we provide an overview of the metabolite composition of resurrection species, summarize the latest reports related to the use of natural products from resurrection plants, and outline their potential for medical applications. (C) 2014 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/3.0/).
Leaves and floral organs grow to distinct, species-specific sizes and shapes. Research over the last few years has increased our understanding of how genetic pathways modulate cell proliferation and cell expansion to determine these sizes and shapes. In particular, the timing of proliferation arrest is an important point of control for organ size, and work on the regulators involved is showing how this control is achieved mechanistically and integrates environmental information. We are also beginning to understand how growth differs in different organs to produce their characteristic shapes, and how growth is integrated between different tissues that make up plant organs. Lastly, components of the general machinery in eukaryotic cells have been identified as having important roles in growth control.
Confusion about model validation is one of the main challenges in using ecological models for decision support, such as the regulation of pesticides. Decision makers need to know whether a model is a sufficiently good representation of its real counterpart and what criteria can be used to answer this question. Unclear terminology is one of the main obstacles to a good understanding of what model validation is, how it works, and what it can deliver. Therefore, we performed a literature review and derived a standard set of terms. 'Validation' was identified as a catch-all term, which is thus useless for any practical purpose. We introduce the term 'evaludation', a fusion of 'evaluation' and 'validation', to describe the entire process of assessing a model's quality and reliability. Considering the iterative nature of model development, the modelling cycle, we identified six essential elements of evaludation: (i) 'data evaluation' for scrutinising the quality of numerical and qualitative data used for model development and testing; (ii) 'conceptual model evaluation' for examining the simplifying assumptions underlying a model's design; (iii) 'implementation verification' for testing the model's implementation in equations and as a computer programme; (iv) 'model output verification' for comparing model output to data and patterns that guided model design and were possibly used for calibration; (v) 'model analysis' for exploring the model's sensitivity to changes in parameters and process formulations to make sure that the mechanistic basis of main behaviours of the model has been well understood; and (vi) 'model output corroboration' for comparing model output to new data and patterns that were not used for model development and parameterisation. Currently, most decision makers require 'validating' a model by testing its predictions with new experiments or data. Despite being desirable, this is neither sufficient nor necessary for a model to be useful for decision support. We believe that the proposed set of terms and its relation to the modelling cycle can help to make quality assessments and reality checks of ecological models more comprehensive and transparent. (C) 2013 Elsevier B.V. All rights reserved.
A class of adsorbents currently receiving growing attention is the clay-polymer nanocomposite (CPN) adsorbents. CPNs effectively treat water by adsorption and flocculation of both inorganic and organic micropollutants from aqueous solutions. Some of these CPNs - when modified with biocides - also have the ability to efficiently remove microorganisms such as Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Candida albicans from water. CPNs are far more easily recovered from aqueous media than neat clay. They also exhibit far better treatment times than either polymer or clay adsorbents. They have higher adsorption capacity and better life cycles compared with clay alone. CPNs therefore show an excellent potential as highly efficient water and waste treatment agents.
This article reviews the various CPNs that have been prepared recently and used as adsorbents in the removal of micropollutants (inorganic, organic and biological) from aqueous solutions. A special focus is placed on CPNs that are not only interesting from an academic point of view but also effectively reduce the concentration of micropollutants in water to safe limits and also on new developments bordering on CPN use as water treatment agent that have not yet realized their full potential. (C) 2014 Elsevier B.V. All rights reserved.
Background: Post-activation potentiation (PAP) can elicit acute performance enhancements in variables of strength, power, and speed. However, it is unresolved whether the frequent integration of PAP eliciting conditioning activities in training (i.e., complex training) results in long-term adaptations. In this regard, it is of interest to know whether complex training results in larger performance enhancements as compared to more traditional and isolated training regimens (e. g., resistance training). Thus, this systematic literature review summarises the current state of the art regarding the effects of complex training on measures of strength, power, and speed in recreational, subelite, and elite athletes. Further, it provides information on training volume and intensities that proved to be effective.
Methods: Our literature search included the electronic databases Pubmed, SportDiscus, and Web of Science (1995 to September 2013). In total, 17 studies met the inclusionary criteria for review. Ten studies examined alternating complex training and 7 studies sequenced complex training.
Results: Our findings indicated small to large effects for both alternating complex training (countermovement jump height: +7.4 % [ESd = -0.43]; squat jump height: +9.8 % [ESd = -0.66]; sprint time: -2.4% [ESd = 0.63]) and sequenced complex training (countermovement jump height: +6.0 % [ESd = -0.83]; squat jump height: +11.9% [ESd = -0.97], sprint time: -0.7% [ESd = 0.52]) in measures of power and speed. As compared to more traditional training regimens, alternating and sequenced complex training showed only small effects in measures of strength, power, and speed. A more detailed analysis of alternating complex training revealed larger effects in countermovement jump height in recreational athletes (+9.7% [ESd = -0.57]) as compared to subelite and elite athletes (+2.7% [ESd = -0.15]). Based on the relevant and currently available literature, missing data (e.g., time for rest interval) and diverse information regarding training volume and intensity do not allow us to establish evidence-based dose-response relations for complex training.
Conclusion: Complex training represents an effective training regimen for athletes if the goal is to enhance strength, power, and speed. Studies with high methodological quality have to be conducted in the future to elucidate whether complex training is less, similar, or even more effective compared to more traditional training regimens. Finally, it should be clarified whether alternated and/or sequenced conditioning activities implemented in complex training actually elicit acute PAP effects.
New low-temperature thermochronological data from 80 samples in eastern Kyrgyzstan are combined with previously published data from 61 samples to constrain exhumation in a number of mountain ranges in the Central Kyrgyz Tien Shan. All sampled ranges are found to have a broadly consistent Cenozoic exhumation history, characterized by initially low cooling rates (<1 degrees C/Myr) followed by a series of increases in exhumation that occurred diachronously across the region in the late Cenozoic that are interpreted to record the onset of deformation in different mountain ranges. Combined with geological estimates for the onset of proximal deformation, our data suggest that the Central Kyrgyz Tien Shan started deforming in the late Oligocene-early Miocene, leading to the development of several, widely spaced mountain ranges separated by large intermontane basins. Subsequently, more ranges have been constructed in response to significant shortening increases across the Central Kyrgyz Tien Shan, notably in the late Miocene. The order of range construction is interpreted to reflect variations in the susceptibility of inherited structures to reactivation. Reactivated structures are also shown to have significance along strike variations in fault vergence and displacement, which have influenced the development and growth of individual mountain ranges. Moreover, the timing of deformation allows the former extent of many intermontane basins that have since been partitioned to be inferred; this can be linked to the highly time-transgressive onset of late Cenozoic coarse clastic sedimentation.
Rezensiertes Werk
George, Rosemary Marangoly, Indian English and the Fiction of National Literature - Cambridge: Cambridge University Press, 2013. - Hb. viii, 285 pp. - (Zeitschrift für Anglistik und Amerikanistik ; 62(4))
ISBN 978-1-107-04000-7.
In der verdienstvollen Reihe der Abhandlungen der Studiengruppe für Politik und Völkerrecht ist ein gerade jetzt – Ukraine/Krim-Krise! – höchst aktueller Band zum Thema Selbstbestimmungsrecht der Völker erschienen. Der Band, der die auf einer Tagung der Hanns-Seidel-Stiftung in Verbindung mit der Kulturstiftung der deutschen Vertriebenen im Dezember 2010 gehaltenen Vorträge umfasst, präsentiert keine grundstürzend neuen Erkenntnisse, aber die mit dem Selbstbestimmungsrecht verbundenen Probleme werden in aller Regel übersichtlich dargestellt und erörtert. So ist das Fundament bereitet, auf dem auch die neueren Ereignisse sinnvoll diskutiert werden können. In diesem Zusammenhang soll auch auf frühere Arbeiten der Studiengruppe aufmerksam gemacht werden, die im vorliegenden Band freilich erstaunlich wenig, jedenfalls nicht erkennbar, ausgewertet werden.