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The ability to breathe air represents a fundamental step in vertebrate evolution that was accompanied by several anatomical and physiological adaptations. The morphology of the air-blood barrier is highly conserved within air-breathing vertebrates. It is formed by three different plies, which are represented by the alveolar epithelium, the basal lamina, and the endothelial layer. Besides these conserved morphological elements, another common feature of vertebrate lungs is that they contain a certain amount of fluid that covers the alveolar epithelium. The volume and composition of the alveolar fluid is regulated by transepithelial ion transport mechanisms expressed in alveolar epithelial cells. These transport mechanisms have been reviewed extensively. Therefore, the present review focuses on the properties and functional significance of the alveolar fluid. How does the fluid enter the alveoli? What is the fate of the fluid in the alveoli? What is the function of the alveolar fluid in the lungs? The review highlights the importance of the alveolar fluid, its volume and its composition. Maintenance of the fluid volume and composition within certain limits is critical to facilitate gas exchange. We propose that the alveolar fluid is an essential element of the air-blood barrier. Therefore, it is appropriate to refer to this barrier as being formed by four plies, namely (1) the thin fluid layer covering the apical membrane of the epithelial cells, (2) the epithelial cell layer, (3) the basal membrane, and (4) the endothelial cells.
The vectorial transport of Na+ across epithelia is crucial for the maintenance of Na+ and water homeostasis in organs such as the kidneys, lung, or intestine. Dysregulated Na+ transport processes are associated with various human diseases such as hypertension, the salt-wasting syndrome pseudohypoaldosteronism type 1, pulmonary edema, cystic fibrosis, or intestinal disorders, which indicate that a precise regulation of epithelial Na+ transport is essential. Novel regulatory signaling molecules are gasotransmitters. There are currently three known gasotransmitters: nitric oxide (NO), carbon monoxide (CO), and hydrogen sulfide (H2S). These molecules are endogenously produced in mammalian cells by specific enzymes and have been shown to regulate various physiological processes. There is a growing body of evidence which indicates that gasotransmitters may also regulate Na+ transport across epithelia. This review will summarize the available data concerning NO, CO, and H2S dependent regulation of epithelial Na+ transport processes and will discuss whether or not these mediators can be considered as true physiological regulators of epithelial Na+ transport biology.
Wesch D, Althaus M, Miranda P, Cruz-Muros I, Fronius M, Gonzalez-Hernandez T, Clauss WG, de la Rosa DA, Giraldez T. Differential N termini in epithelial Na+ channel delta-subunit isoforms modulate channel trafficking to the membrane. Am J Physiol Cell Physiol 302: C868-C879, 2012. First published December 7, 2011; doi: 10.1152/ajpcell.00255.2011.-The epithelial Na+ channel (ENaC) is a heteromultimeric ion channel that plays a key role in Na+ reabsorption across tight epithelia. The canonical ENaC is formed by three analogous subunits, alpha, beta, and gamma. A fourth ENaC subunit, named delta, is expressed in the nervous system of primates, where its role is unknown. The human delta-ENaC gene generates at least two splice isoforms, delta(1) and delta(2), differing in the N-terminal sequence. Neurons in diverse areas of the human and monkey brain differentially express either delta(1) or delta(2), with few cells coexpressing both isoforms, which suggests that they may play specific physiological roles. Here we show that heterologous expression of delta(1) in Xenopus oocytes and HEK293 cells produces higher current levels than delta(2). Patch-clamp experiments showed no differences in single channel current magnitude and open probability between isoforms. Steady-state plasma membrane abundance accounts for the dissimilarity in macroscopic current levels. Differential trafficking between isoforms is independent of beta- and gamma-subunits, PY-motif-mediated endocytosis, or the presence of additional lysine residues in delta(2)-N terminus. Analysis of delta(2)-N terminus identified two sequences that independently reduce channel abundance in the plasma membrane. The delta(1) higher abundance is consistent with an increased insertion rate into the membrane, since endocytosis rates of both isoforms are indistinguishable. Finally, we conclude that delta-ENaC undergoes dynamin-independent endocytosis as opposed to alpha beta gamma-channels.
The gasotransmitter hydrogen sulphide decreases Na⁺ transport across pulmonary epithelial cells
(2012)
BACKGROUND AND PURPOSE The transepithelial absorption of Na(+) in the lungs is crucial for the maintenance of the volume and composition of epithelial lining fluid. The regulation of Na(+) transport is essential, because hypo- or hyperabsorption of Na(+) is associated with lung diseases such as pulmonary oedema or cystic fibrosis. This study investigated the effects of the gaseous signalling molecule hydrogen sulphide (H(2) S) on Na(+) absorption across pulmonary epithelial cells. EXPERIMENTAL APPROACH Ion transport processes were electrophysiologically assessed in Ussing chambers on H441 cells grown on permeable supports at air/liquid interface and on native tracheal preparations of pigs and mice. The effects of H(2)S were further investigated on Na(+) channels expressed in Xenopus oocytes and Na(+) /K(+)-ATPase activity in vitro. Membrane abundance of Na(+) /K(+)-ATPase was determined by surface biotinylation and Western blot. Cellular ATP concentrations were measured colorimetrically, and cytosolic Ca(2+) concentrations were measured with Fura-2. KEY RESULTS H(2)S rapidly and reversibly inhibited Na(+) transport in all the models employed. H(2)S had no effect on Na(+) channels, whereas it decreased Na(+) /K(+)-ATPase currents. H(2)S did not affect the membrane abundance of Na(+) /K(+)-ATPase, its metabolic or calcium-dependent regulation, or its direct activity. However, H(2)S inhibited basolateral calcium-dependent K(+) channels, which consequently decreased Na(+) absorption by H441 monolayers. CONCLUSIONS AND IMPLICATIONS H(2) S impairs pulmonary transepithelial Na(+) absorption, mainly by inhibiting basolateral Ca(2+)-dependent K(+) channels. These data suggest that the H(2)S signalling system might represent a novel pharmacological target for modifying pulmonary transepithelial Na(+) transport.
Multi-hop Netze sind seit vielen Jahren Forschungsthema. Seit einigen Jahren gibt es auch erste Realisierungen solcher Netze. Sie ermöglichen es, ohne feste Infrastruktur sich selbst organisierende Netze zu realisieren. Dies macht sie für vielfältige zivile wie taktische Szenarien interessant. In der vorliegenden Arbeit liegt der Fokus auf taktischen Szenarien, wie Szenarien der öffentlichen Sicherheit, militärischen oder Katastrophenszenarien. In solchen Szenarien kann für die Kommunikation auf der letzten Meile nicht von existierender Kommunikationsinfrastruktur ausgegangen werden. Taktische multi-hop Netze stellen eine Möglichkeit dar, die Kommunikation auf der letzen Meile trotzdem zu realisieren.
Malware is responsible for massive economic damage. Being the preferred tool for digital crime, botnets are becoming increasingly sophisticated, using more and more resilient, distributed infrastructures based on peer-to-peer (P2P) protocols. On the other side, current investigation techniques for malware and botnets on a technical level are time-consuming and highly complex. Fraunhofer FKIE is addressing this problem, researching new ways of intelligent process automation and information management for malware analysis in order to minimize the time needed to investigate these threats.
Today’s computer systems face a vast array of severe threats that are posed by automated attacks performed by malicious software as well as manual attacks by individual humans. These attacks not only differ in their technical implementation but may also be location-dependent. Consequentially, it is necessary to join the information from heterogeneous and distributed attack sensors in order to acquire comprehensive information on current ongoing cyber attacks.
XML Encryption and XML Signature are fundamental security standards forming the core for many applications which require to process XML-based data. Due to the increased usage of XML in distributed systems and platforms such as in SOA and Cloud settings, the demand for robust and effective security mechanisms increased as well. Recent research work discovered, however, substantial vulnerabilities in these standards as well as in the vast majority of the available implementations. Amongst them, the so-called XML Signature Wrapping attack belongs to the most relevant ones. With the many possible instances of this attack type, it is feasible to annul security systems relying on XML Signature and to gain access to protected resources as has been successfully demonstrated lately for various Cloud infrastructures and services. This paper contributes a comprehensive approach to robust and effective XML Signatures for SOAP-based Web Services. An architecture is proposed, which integrates the r equired enhancements to ensure a fail-safe and robust signature generation and verification. Following this architecture, a hardened XML Signature library has been implemented. The obtained evaluation results show that the developed concept and library provide the targeted robustness against all kinds of known XML Signature Wrapping attacks. Furthermore the empirical results underline, that these security merits are obtained at low efficiency and performance costs as well as remain compliant with the underlying standards.
3D Time-of-Flight (ToF)
(2012)
Lichtlaufzeitsensor
(2012)
Lichtlaufzeitkamera
(2012)
In this paper we summarize our research on international educational contexts and transfer the results to the context of urban life-long learning. We will show that a collection and provision of relevant data can help instructors as well as learners to raise their awareness regarding contextual differences, to develop a higher level of acceptance regarding differences, and thus, in the long term, avoid frustration in educational processes and reduce drop out-rates.
In the context of Internet-based e-Learning, including an international auditory is a logical consequence. However, due to uncertainty regarding the foreign learners, e-Learning programs often are limited to local or national participants. Understanding the different expectations of learners regarding instructor-support is one step in order to enable providers of educational services to tailor educational programs that fit the requirements of an international auditory. We asked university students in five countries regarding their expectations towards instructor-support and found major differences between the investigated countries.
For learners, feedback can be both, a strong motivator but in case it fails its purpose, it can be a strong reason for frustration and dropouts as well. Do we have to change our locally implemented feedback strategies when adapting learning contents from national to international settings? In our study, we the investigated learners’ understanding and preferences regarding feedback in scenarios of higher education across the five different national contexts, Bulgaria, Germany, South Korea, Turkey, and Ukraine.
This presentation shows that students in different cultural contexts have different perceptions of time management and work organization. Particularly in group work scenarios, such differences can have a frustrating impact on students from other cultural contexts because e.g., expectations are not met. Being aware of such differences between the learners in a culturally heterogeneous educational scenario, educators can prevent frustration by introducing their students and providing more specific instructions.
Education is widely seen as an important means of addressing both national and international problems, such as political or religious extremism, poverty, and hunger. If publicly available educational resources (OERs) shall help overcoming the educational gap, localization is one of the major issues we need to deal with. Educators as well as learners need to be supported to determine adaptation needs. This paper provides a list of possible in-fluence factors on educational scenarios which are defined as context metadata. In the given form, the list needs to be understood as an addendum for the paper entitled ‘Open Educational Resources: Education for the World?’ from Thomas richter and Maggie McPherson; It is being published in the volume 3, issue 2 of the Journal Distance Education in 2012.
Education is widely seen as an important means of addressing both national and international problems, such as political or religious extremism, poverty, and hunger. However, if developing countries are to become societies that can compete properly with Western industrialized countries, not only is a fundamental shift in thinking with regard to the value of education and more/better provision of teaching required, but strong support from other countries is needed as well. This article explores questions such as whether Western policymakers can avoid a repetition of some of the failures of the past few decades in terms of providing foreign aid; how educators and providers of educational scenarios and learning contents can foster and manage the creation of a worldwide knowledge society; and in particular, if the provision of open educational resources (OER) can realistically overcome the educational gap and foster educational justice.
Disorders of the degradation of branched chain amino acids: what is new in clinics and laboratories?
(2012)
Molybdenum cofactor deficiency (MoCD) is a rare inherited metabolic disorder characterized by severe and progressive neurological damage mainly caused by the loss of sulfite oxidase activity. Elevated urinary levels of sulfite, thiosulfate, and S-sulfocysteine (SSC) are hallmarks in the diagnosis of MoCD and sulfite oxidase deficiency (SOD). Recently, a first successful treatment of a human MoCD type A patient based on a substitution therapy with the molybdenum cofactor precursor cPMP has been reported, resulting in nearly complete normalization of MoCD biomarkers. Knowing the rapid progression of the disease symptoms in nontreated patients, an early diagnosis of MoCD as well as a sensitive method to monitor daily changes in SSC levels, a key marker of sulfite toxicity, is crucial for treatment outcome. Here, we describe a fast and sensitive method for the analysis of SSC in human urine samples using high performance liquid chromatography (HPLC). The analysis is based on precolumn derivatization with O-phthaldialdehyde (OPA) and separation on a C18 reverse phase column coupled to UV detection. The method was extended to human serum analysis and no interference with endogenous amino acids was found. Finally, SSC values from 45 pediatric urine, 75 adult urine, and 24 serum samples from control individuals as well as MoCD patients are reported. Our method represents a cost-effective technique for routine diagnosis of MoCD and SOD, and can be used also to monitor treatment efficiency in those sulfite toxicity disorders on a daily basis.
The osmolality of nonionic, iodinated contrast agents as an important factor for renal safety
(2012)
Germany
(2012)
In this paper, various enhanced sales forecast methodologies and models for the automobile market are presented. The methods used deliver highly accurate predictions while maintaining the ability to explain the underlying model at the same time. The representation of the economic training data is discussed, as well as its effects on the newly registered automobiles to be predicted. The methodology mainly consists of time series analysis and classical Data Mining algorithms, whereas the data is composed of absolute and/or relative market-specific exogenous parameters on a yearly, quarterly, or monthly base. It can be concluded that the monthly forecasts were especially improved by this enhanced methodology using absolute, normalized exogenous parameters. Decision Trees are considered as the most suitable method in this case, being both accurate and explicable. The German and the US-American automobile market are presented for the evaluation of the forecast models.
Computational chemistry began with the birth of computers in the mid 1900s, and its growth has been directly coupled to the technological advances made in computer science and high-performance computing. A popular goal within the field, be it Newtonian or quantum based methods, is the accurate modelling of physical forces and energetics through mathematics and algorithm design. Through reliable modelling of the underlying forces, molecular simulations frequently provide atomistic insights into macroscopic experimental observations.
This book constitutes the thoroughly refereed post-conference proceedings of the Third International ICST Conference on e-Infrastructure and e-Services for Developing Countries, AFRICOMM 2011, held in Zanzibar, Tansania, in November 2011. The 24 revised full papers presented together with 2 poster papers were carefully reviewed and selected from numerous submissions. The papers cover a wide range of topics in the field of information and communication infrastructures. They are organized in two tracks: communication infrastructures for developing countries and electronic services, ICT policy, and regulatory issues for developing countries.
The topic of this PhD project is in the context of cross-reality, a term that defines mixed reality environments that tunnel dense real-world data acquired through the use of sensor/actuator device networks into virtual worlds. It is part of the ongoing academia and industry efforts to achieve interoperability between virtual and real devices and services.
This paper describes the development of a Pedelec controller whose performance level (PL) conforms to European standard on safety of machinery [9] and whose soft- ware is verified to conform to EPAC standard [6] by means of a software verification technique called model checking. In compliance with the standard [9] the hardware needs to implement the required properties corresponding to categories “C” and “D”. The latter is used if the breaks are not able to bring the velomobile with a broken motor controller to a full stop. Therefore the controller needs to implement a test unit, which verifies the functionality of the components and, in case of an emergency, shuts the whole hardware down to prevent injuries of the cyclist. The MTTFd can be measured through a failure graph, which is the result of a FMEA analysis, and can be used to proof that the Pedelec controller meets the regulations of the system specification. The analysis of the system in compliance with [9] usually treats the software as a black box thus ignoring its inner workings and validating its correctness by means of testing. In this paper we present a temporal logic specification according to [6], based on which the software for the Pedelec controller is implemented, and verify instead of only testing its functionality. By means of model checking [1] we proof that the software fulfills all requirements which are regulated by its specification.
Designing stereoscopic information visualization for 3D-TV: What can we learn from S3D gaming?
(2012)
This paper explores graphical design and spatial alignment of visual information and graphical elements into stereoscopically filmed content, e.g. captions, subtitles, and especially more complex elements in 3D-TV productions. The method used is a descriptive analysis of existing computer- and video games that have been adapted for stereoscopic display using semi-automatic rendering techniques (e.g. Nvidia 3D Vision) or games which have been specifically designed for stereoscopic vision. Digital games often feature compelling visual interfaces that combine high usability with creative visual design. We explore selected examples of game interfaces in stereoscopic vision regarding their stereoscopic characteristics, how they draw attention, how we judge effect and comfort and where the interfaces fail. As a result, we propose a list of five aspects which should be considered when designing stereoscopic visual information: explicit information, implicit information, spatial reference, drawing attention, and vertical alignment. We discuss possible consequences, opportunities and challenges for integrating visual information elements into 3D-TV content. This work shall further help to improve current editing systems and identifies a need for future editing systems for 3DTV, e.g., live editing and real-time alignment of visual information into 3D footage.
We present a study that investigates user performance benefits of playing video games using 3D motion controllers in 3D stereoscopic vision in comparison to monoscopic viewing. Using the PlayStation 3 game console coupled with the PlayStation Move Controller, we explored five different games that combine 3D stereo and 3D spatial interaction. For each game, quantitative and qualitative measures were taken to determine if users performed better and learned faster in the experimental group (3D stereo display) than in the control group (2D display). A game expertise pre-questionnaire was used to classify participants into beginners and expert game player categories to analyze a possible impact on performance differences. The results show two cases where the 3D stereo display did help participants perform significantly better than with a 2D display. For the first time, we can report a positive effect on gaming performance based on stereoscopic vision, although reserved to isolated tasks and depending on game expertise. We discuss the reasons behind these findings and provide recommendations for game designers who want to make use of 3D stereoscopic vision and 3D motion control to enhance game experiences.
Recent advances in digital game technology are making stereoscopic games more popular. Stereoscopic 3D graphics promise a better gaming experience but this potential has not yet been proven empirically. In this paper, we present a comprehensive study that evaluates player experience of three stereoscopic games in comparison with their monoscopic counterparts. We examined 60 participants, each playing one of the three games, using three self-reporting questionnaires and one psychophysiological instrument. Our main results are (1) stereoscopy in games increased experienced immersion, spatial presence, and simulator sickness; (2) the effects strongly differed across the three games and for both genders, indicating more affect on male users and with games involving depth animations; (3) results related to attention and cognitive involvement indicate more direct and less thoughtful interactions with stereoscopic games, pointing towards a more natural experience through stereoscopy.
Nützt oder schadet ethisches Verhalten der Karriere und dem Erfolg der Mitarbeiter und ihrer Unternehmen? Wenn man gerade die letzten 10 Entwicklungsjahre in vielen Unternehmen sieht, könnte man spontan die Meinung vertreten, dass Ethik und Moral der Karriere eher schadet, legt man den Maßstab an moralische Qualitäten des täglichen Handelns.
CSR als Führungskonzept
(2012)
Eine neue Kultur der Verantwortung – Was Politik und Gesellschaft von Unternehmen erwarten müssen
(2012)
Die Frage der Wertorientierungen wirtschaftlichen und politischen Handelns gewinnt immer dann ein öffentliches Interesse, wenn soziale Probleme oder Konflikte von existenzieller Bedeutung für die Betroffenen auftreten. Ist es richtig, das Unternehmenswohl höher einzustufen als das Wohl der Mitarbeiter und ihrer Familien?
Vermitteln von Werten
(2012)