The Technische Universität Dresden is the largest institute of higher education in the city of Dresden, the largest university in Saxony and one of the 10 largest universities in Germany with 37,134 students as of 2013. The name Technische Universität Dresden has only been used since 1961; the history of the university, however, goes back nearly 200 years to 1828. This makes it one of the oldest colleges of technology in Germany, and one of the country’s oldest universities, which in German today refers to institutes of higher education which cover the entire curriculum. The university is member of TU9, a consortium of the nine leading German Institutes of Technology. The university is one of the eleven German universities which succeeded in the Excellence Initiative in 2012, thus getting the title of a "University of Excellence". The TU Dresden succeeded in all three rounds of the German Universities Excellence Initiative . Wikipedia.
Beckmann M.,TU Dresden
Waste management & research : the journal of the International Solid Wastes and Public Cleansing Association, ISWA | Year: 2012
The waste treatment, particularly the thermal treatment of waste has changed fundamentally in the last 20 years, i.e. from facilities solely dedicated to the thermal treatment of waste to facilities, which in addition to that ensure the safe plant operation and fulfill very ambitious criteria regarding emission reduction, resource recovery and energy efficiency as well. Therefore this contributes to the economic use of raw materials and due to the energy recovered from waste also to the energy provision. The development described had the consequence that waste and solid recovered fuels (SRF) has to be evaluated based on fuel criteria as well. Fossil fuels - coal, crude oil, natural gas etc. have been extensively investigated due to their application in plants for energy conversion and also due to their use in the primary industry. Thereby depending on the respective processes, criteria on fuel technical properties can be derived. The methods for engineering analysis of regular fuels (fossil fuels) can be transferred only partially to SRF. For this reason methods are being developed or adapted to current analytical methods for the characterization of SRF. In this paper the possibilities of the energetic utilization of SRF and the characterization of SRF before and during the energetic utilization will be discussed.
Aringer M.,TU Dresden |
Vital E.,University of Leeds
Arthritis Research and Therapy | Year: 2012
Autoantibodies may be found years before an autoimmune disease becomes clinically apparent. For systemic lupus erythematosus (SLE), those to RNA-binding proteins, to phospholipids, and to double-stranded DNA, in particular, have been found in sera of SLE patients years before the diagnosis was made. New data now show in an unbiased way that, in patients with early SLE, no single antibody class or specificity is associated with progression to SLE. Rather, an increasing number of autoantibody specificities, such as to thyroid antigens, was observed in patients progressing. This points to more generalized B cell autoreactivity during progression to SLE, underlying lupus disease manifestations. © 2013 BioMed Central Ltd.
Weber N.,TU Dresden
Forest Policy and Economics | Year: 2012
Theories constitute an important part of science and contribute to its advancement. As a consequence of the variety of scientific approaches available, students of forest policy can choose between three alternatives: (i) relying on and applying an existing theory, (ii) attempting to combine several theories in a new context or (iii) creating a new theory based on their own experiences and findings from desk research and/or empirical surveys. Whereas alternatives (i) and (ii) have been chosen in the majority of scientific studies focusing on the relationship between forests and people, theory building has not as yet been commonly applied in forest policy research. Seeking to discern both the advantages and disadvantages of these approaches, the methodological aspects of each are emphasised in this paper. Subsequent to an outline of the general significance of theories for scientific research practised in the social sciences, and a depiction of the features of 'good' theories, the widespread procedure for testing existing theories is outlined. This is followed by descriptions of several techniques employed in theory building. Finally, some conclusions on the application of existing theories and on theory building in the context of forest policy are presented. It is argued that given its innovative potential, theory building should not be neglected in forest policy discipline. © 2011 Elsevier B.V.
Hummel T.,TU Dresden |
Lotsch J.,Goethe University Frankfurt
Archives of Otolaryngology - Head and Neck Surgery | Year: 2010
Objective: To determine appropriate counseling of patients with olfactory dysfunction. Design: Retrospective analysis. Setting: Interdisciplinary Center for Smell and Taste, University of Dresden Medical School, Technical University of Dresden. Patients: A total of 361 males and 533 females, aged 11 to 84 years, who twice reported to the Interdisciplinary Center for Smell and Taste. Main Outcome Measures: Residual olfactory performance, duration of olfactory loss until first assessment, presence or absence of parosmia or phantosmia, origin of olfactory loss, interval between assessments, age, sex, and smoking habits. Results: Although 431 patients (48.2%) had functional anosmia at the first olfactory assessment, 444 (49.7%) had hyposmia, and 19 (2.1%) had normosmia; at the second assessment, 278 (31.1%) had functional anosmia, 496 (55.5%) had hyposmia, and 120 (13.4%) had normal olfactory function (P<.001). Changes in smell scores depended positively on the initial score and negatively on age and smoking habits. Normosmia was more likely to be restored in females and when residual olfactory function was relatively high. In contrast, the origin of dysfunction had no direct predictive value because it was mostly reflected by initial smell scores. However, in a sub-analysis omitting the initial olfactory performance as a potential predictor, the initial presence of parosmia was associated with a lower probability of anosmia as the final outcome. Conclusion: The prognosis of olfactory dysfunction mainly depends on residual function, sex, parosmia, smoking habits, and age, whereas in this statistical model, origin plays only a second-line role, reflected in different degrees of initial olfactory loss. ©2010 American Medical Association. All rights reserved.
Wittchen H.-U.,TU Dresden
International Journal of Methods in Psychiatric Research | Year: 2010
The K6 scale is a shortened version of the Kl0, a 10-question scale originally developed to provide an efficient population-level screen for serious mental disorders (SMI) in the USA. Evidence that the six-item shortened version performed as well as the original 10-item version, coupled with strong psychometric properties, led to rapid dissemination and replicated validation of the K6 in a number of other countries around the world. Based on these results, the K6 is now often included in large general-purpose government health tracking surveys in a number of different countries. Until now, though, the scoring rules for the K6 in these surveys were inconsistent. The first paper in this special issue introduces the K6 scale and summarizes the results of a series of investigations to resolve these inconsistencies by providing optimal scoring rules for the K6 in 14 countries. Subsequent papers explore the usefulness of the K6 to screen for serious emotional disturbance among adolescents and report findings from validation efforts based on independent diagnostic assessments as well as of other measures of impairment and disability (World Health organization Disability Assessment Scale). Finally a highly innovative analysis using a Bayesian multilevel modeling approach is presented, designed to estimate the prevalence of SMI in small areas, such as cities, states, or schools, from surveys carried out in a larger population that includes only relatively small samples of respondents in each of the areas in which prevalence estimates are to be made. Taken together, these studies demonstrate that the K6 is an efficient and useful screening tool. The psychometric and methodological explorations will hopefully stimulate additional interest in the use of short screening scales in large-scale general health surveys to supplement the more in-depth information obtained in periodic psychiatric epidemiological surveys on the basis of diagnostic interviews. Copyright © 2010 John Wiley & Sons, Ltd.
Beste C.,TU Dresden |
Saft C.,Ruhr University Bochum
Brain Structure and Function | Year: 2013
Chaining or cascading of different actions and responses is necessary to accomplish a goal. Yet, little is known about the functional neuroanatomical–electrophysiological mechanisms mediating these processes. Computational models suggest that medium spiny neurons (MSNs) play an important role in action cascading, but this assumption has hardly been tested relating neuroanatomical and electrophysiological parameters in a human model of circumscribed MSN dysfunction. As a possible human model of circumscribed MSN dysfunction, we investigate benign hereditary chorea in a case–control study applying bootstrap statistics. To investigate these mechanisms, we used a stop–change paradigm, where we apply mathematical constraints to describe the degree of how task goals are activated with more or less overlap during action cascading. We record event-related potentials and analyze neural synchronization processes. The results show that MSN dysfunctions lead to deficits in action cascading processes only when two response options seek simultaneous access to response selection resources. Attentional selection processes are not affected, but processes reflecting the transition between stimulus evaluation and responding are affected. The results underline computational models of MSN functioning and show that dysfunction in these networks leads to a more parallel and hence inefficient response selection. © 2013, Springer-Verlag Berlin Heidelberg.
Gille G.,TU Dresden
Journal of neural transmission (Vienna, Austria : 1996) | Year: 2011
A number of neurodegenerative diseases are associated with iron dyshomeostasis and mitochondrial dysfunction. However, the pathomechanistic interplay between iron and mitochondria varies. This review summarises the physiological role of iron in mitochondria and subsequently exemplifies two neurodegenerative diseases with disturbed iron function in mitochondria: inherited Friedreich ataxia (FRDA) and idiopathic Parkinson disease (PD). In eukaryotes, mitochondria are main consumers of iron. The respiratory chain relies on iron-containing redox systems in the form of complexes I-III with iron-sulphur clusters and cytochromes with haem as prosthetic groups. The bifunctional enzyme aconitase is not only important in the citric acid cycle, but also functions as a key regulator of cell iron metabolism. Haem biosynthesis occurs partially in mitochondria as well as the biogenesis of iron-sulphur clusters that are co-factors in numerous iron-sulphur proteins. FRDA is characterised by a mutation of the frataxin gene, the protein of which serves as an iron chaperone in iron-sulphur cluster assembly. The lack of frataxin expression leads to defective iron-sulphur cluster biogenesis with decreased respiratory and aconitase activity. The resulting mitochondrial iron overload might fuel reactive oxygen species formation and contribute to clinical signs of oxidative stress. PD is typically associated with an increased iron content of the substantia nigra, the causes of which are largely unknown. Recent research demonstrated raised iron levels in individual dopaminergic neurons of the substantia nigra. Moreover, transferrin/transferrin receptor 2 mediated transport of iron into the mitochondria of these neurons was identified together with increased transferrin immunoreactivity. Resulting accumulation of iron into mitochondria might lead to oxidative stress damaging iron-sulphur cluster-containing proteins.
Weber T.,TU Dresden
Cancer investigation | Year: 2013
Recurrence is not reliably predictable in localized clear cell renal cell carcinoma. Proteinmarkers could improve predictive accuracy. Tissue-microarrays from 132 patients with primary localized ccRCC were immunohistochemically analyzed for VHL, Ki67, p53, p21, survivin, and, for microvessel-density, UEA-1. Nuclear stainings of Ki67, p21, and survivin were significantly associated with disease-specific survival and increased predictive ability from 74% to 76%, 77%, and 78%, respectively in a multivariate model including T-stage and Fuhrman grade. A score-variable, combining Ki67-, p21-, and nS-staining identified a subset of patients with high risk of disease recurrence and increased predictive ability in the multivariate model to 84%.
Mai R.,TU Dresden |
Hoffmann S.,University of Rostock
Journal of Consumer Behaviour | Year: 2012
This article identifies consumer segments that differ in the way they consider health-related and health-unrelated food properties when making food choices. The paper makes two assumptions: first, the level of health consciousness determines the quality of the attributes (health related versus health unrelated) these segments consider important; and second, the degree of nutrition-related self-efficacy subsequently defines the quantity of health-related attributes considered important. Two studies measure preferences for food attributes (Study 1: n=54, 12 attributes, conjoint analysis; Study 2: n=162, 25 attributes, constant sum scales). In both studies, cluster analysis identifies two major segments (taste lovers and nutrition fact seekers) that are determined by consumers' level of health consciousness. Study 2 demonstrates that nutrition-related self-efficacy determines how many health-related attributes nutrition fact seekers consider important. Consequently, they can be split into 'heavy' and 'soft' subsegments. The study also identifies a segment that lacks a clear food choice strategy as a result of incompatible beliefs. The paper guides marketers and producers in developing healthy food products tailored to the needs of different target segments. Considering the enormous health expenditures, the studies' results are also beneficial to policy makers and governmental organizations to design social marketing campaigns. © 2012 John Wiley & Sons, Ltd.
Kubeil C.,TU Dresden |
Bund A.,TU Ilmenau
Journal of Physical Chemistry C | Year: 2011
Conical nanopores from various materials (e.g., glass, silicon nitride, PET) were found to rectify ionic currents in electrolytes. Several models and simulations have been developed to explain and quantify this ion current rectification (ICR). In this Article, we apply numerical simulations based on the Poisson-Nernst-Planck equations to study the effect of pore size, electrolyte concentration, and half-cone angles on ICR at glass nanopore membranes. It is shown how the fixed charge on the glass surfaces overlaps with an externally applied transmembrane potential to yield a nonuniform potential distribution inside the pore. We also tried to assess the role of surface currents via the comparison of our numerical results with a simplified model. Surface conductivity seems to have only a weak influence on the total conductivity for pores with relatively low surface charges. Furthermore, our simulations show that for the occurrence of ICR the pore mouth radius r 0 has to be in the order of magnitude of the Debye length , but overlapping of the electrical double layers is not required. Also, the simple dimensionless ratio r0/cannot solely be used quantify ICR. To show this in more detail, the role of the electrical double layer is discussed for different r0/ ratios and half-cone angles. © 2011 American Chemical Society.
Neubert M.,Leibniz Institute For Kristallzuchtung |
Winkler J.,TU Dresden
Journal of Crystal Growth | Year: 2012
This contribution continues an article series [1,2] about the nonlinear model-based control of the Czochralski crystal growth process. The key idea of the presented approach is to use a sophisticated combination of nonlinear model-based and conventional (linear) PI controllers for tracking of both, crystal radius and growth rate. Using heater power and pulling speed as manipulated variables several controller structures are possible. The present part tries to systematize the properties of the materials to be grown in order to get unambiguous decision criteria for a most profitable choice of the controller structure. For this purpose a material specific constant M called interface mobility and a more process specific constant S called system response number are introduced. While the first one summarizes important material properties like thermal conductivity and latent heat the latter one characterizes the process by evaluating the average axial thermal gradients at the phase boundary and the actual growth rate at which the crystal is grown. Furthermore these characteristic numbers are useful for establishing a scheduling strategy for the PI controller parameters in order to improve the controller performance. Finally, both numbers give a better understanding of the general thermal system dynamics of the Czochralski technique. © 2012 Elsevier B.V.
Nedelkova M.,TU Dresden
Nucleic acids research | Year: 2011
Studying genetic variations in the human genome is important for understanding phenotypes and complex traits, including rare personal variations and their associations with disease. The interpretation of polymorphisms requires reliable methods to isolate natural genetic variations, including combinations of variations, in a format suitable for downstream analysis. Here, we describe a strategy for targeted isolation of large regions (∼35kb) from human genomes that is also applicable to any genome of interest. The method relies on recombineering to fish out target fosmid clones from pools and thereby circumvents the laborious need to plate and screen thousands of individual clones. To optimize the method, a new highly recombineering-efficient bacterial host, including inducible TrfA for fosmid copy number amplification, was developed. Various regions were isolated from human embryonic stem cell lines and a personal genome, including highly repetitive and duplicated ones. The maternal and paternal alleles at the MECP2/IRAK 1 loci were distinguished based on identification of novel allele-specific single-nucleotide polymorphisms in regulatory regions. Additionally, we applied further recombineering to construct isogenic targeting vectors for patient-specific applications. These methods will facilitate work to understand the linkage between personal variations and disease propensity, as well as possibilities for personal genome surgery.
Fritz L.,University of Cologne |
Vojta M.,TU Dresden
Reports on Progress in Physics | Year: 2013
This article summarizes our understanding of the Kondo effect in graphene, primarily from a theoretical perspective. We shall describe different ways to create magnetic moments in graphene, either by adatom deposition or via defects. For dilute moments, the theoretical description is in terms of effective Anderson or Kondo impurity models coupled to graphene's Dirac electrons. We shall discuss in detail the physics of these models, including their quantum phase transitions and the effect of carrier doping, and confront this with existing experimental data. Finally, we will point out connections to other quantum impurity problems, e.g., in unconventional superconductors, topological insulators, and quantum spin liquids. © 2013 IOP Publishing Ltd.
Beck A.,Charite - Medical University of Berlin |
Wustenberg T.,Charite - Medical University of Berlin |
Genauck A.,Charite - Medical University of Berlin |
Wrase J.,Charite - Medical University of Berlin |
And 4 more authors.
Archives of General Psychiatry | Year: 2012
Context: In alcohol-dependent patients, brain atrophy and functional brain activation elicited by alcohol-associated stimuli may predict relapse. However, to date, the interaction between both factors has not been studied. Objective: To determine whether results from structural and functional magnetic resonance imaging are associated with relapse in detoxified alcohol-dependent patients. Design: A cue-reactivity functional magnetic resonance experiment with alcohol-associated and neutral stimuli. After a follow-up period of 3 months, the group of 46 detoxified alcohol-dependent patients was subdivided into 16 abstainers and 30 relapsers. Setting: Faculty for Clinical Medicine Mannheim at the University of Heidelberg, Germany. Participants : A total of 46 detoxified alcohol-dependent patients and 46 age- and sex-matched healthy control subjects Main Outcome Measures: Local gray matter volume, local stimulus-related functional magnetic resonance imaging activation, joint analyses of structural and functional data with Biological Parametric Mapping, and connectivity analyses adopting the psychophysiological interaction approach. Results: Subsequent relapsers showed pronounced atrophy in the bilateral orbitofrontal cortex and in the right medial prefrontal and anterior cingulate cortex, compared with healthy controls and patients who remained abstinent. The local gray matter volume-corrected brain response elicited by alcohol-associated vs neutral stimuli in the left medial prefrontal cortex was enhanced for subsequent relapsers, whereas abstainers displayed an increased neural response in the midbrain (the ventral tegmental area extending into the subthalamic nucleus) and ventral striatum. For alcohol-associated vs neutral stimuli in abstainers compared with relapsers, the analyses of the psychophysiological interaction showed a stronger functional connectivity between the midbrain and the left amygdala and between the midbrain and the left orbitofrontal cortex. Conclusions : Subsequent relapsers displayed increased brain atrophy in brain areas associated with error monitoring and behavioral control. Correcting for gray matter reductions, we found that, in these patients, alcohol-related cues elicited increased activation in brain areas associated with attentional bias toward these cues and that, in patients who remained abstinent, increased activation and connectivity were observed in brain areas associated with processing of salient or aversive stimuli. ©2012 American Medical Association. All rights reserved.
Aust D.E.,TU Dresden
Pathologe | Year: 2011
The new WHO classification of tumors of the digestive system not only redefines common diagnostic terms, such as intraepithelial neoplasia and dysplasia but also introduces changes in the nomenclature and diagnostics of colorectal tumors which will be important in daily practice. Changes in nomenclature and classification include the introduction of serrated adenocarcinoma, cribriform comedo type adenocarcinoma and micropapillary adenocarcinoma as new distinct histological subtypes of colorectal cancer. The grading of mucinous and signet ring carcinomas, which were previously invariably graded as G3/high grade, is now dependent on the microsatellite instability (MSI) status as a high MSI (MSI-H) indicates a better and low or no MSI (MSI-L/MSS) a worse prognosis. Thus, analysis of microsatellite instability via immunohistochemistry or fragment length analysis must be included in the pathological report of these tumors. Serrated polyps/adenomas and their potential of progression into colorectal cancer via the alternative pathway of colorectal carcinogenesis will be discussed as well as new insights into prognostic and predictive markers of colorectal cancer. This manuscript will give an overview of the most important changes within the new WHO classification of colorectal tumors. © 2011 Springer-Verlag.
Ganz J.,University of Oregon |
Brand M.,TU Dresden
Cold Spring Harbor Perspectives in Biology | Year: 2016
Teleost fish have a remarkable neurogenic and regenerative capacity in the adult throughout the rostrocaudal axis of the brain. The distribution of proliferation zones shows a remarkable conservation, even in distantly related teleost species, suggesting a common teleost ground plan of proliferation zones. There are different progenitor populations in the neurogenic niches—progenitors positive for radial glial markers (dorsal telencephalon, hypothalamus) and progenitors with neuroepithelial-like characteristics (ventral telencephalon, optic tectum, cerebellum). Definition of these progenitors has allowed studying their role in normal growth of the adult brain, but also when challenged following a lesion. From these studies, important roles have emerged for intrinsic mechanisms and extrinsic signals controlling the activation of adult neurogenesis that enable regeneration of the adult brain to occur, opening up new perspectives on rekindling regeneration also in the context of the mammalian brain. © 2016 Cold Spring Harbor Laboratory Press; all rights reserved.
Marsch P.,Nokia Inc. |
Fettweis G.,TU Dresden
IEEE Transactions on Wireless Communications | Year: 2011
Coordinated Multi-Point (CoMP) is known to be a key technology for next generation mobile communications systems, as it allows to overcome the burden of inter-cell interference. Especially in the uplink, it is likely that interference exploitation schemes will be used in the near future, as they can be used with legacy terminals and be based on operator-proprietary signal processing concepts, hence requiring no or little changes in standardization. Major drawbacks, however, are the extent of additional backhaul infrastructure needed, and the sensitivity to imperfect channel knowledge. This paper jointly addresses both issues in a new framework incorporating a multitude of proposed theoretical uplink CoMP concepts, which are then put into perspective with practical CoMP algorithms. This comprehensive analysis provides new insight into the potential value of different uplink CoMP concepts in next generation wireless communications systems, and reveals the subset of schemes that are most likely to be used in practice. © 2011 IEEE.
Lezana P.,Federico Santa Maria Technical University |
Aceiton R.,TU Dresden
IEEE Transactions on Industrial Electronics | Year: 2011
Multilevel converters have become an interesting alternative for medium- and high-voltage drives over the last decade. Among the existing alternatives, multicell structures offer advantages due to their modularity and scalability. This paper presents experimental results of a recently introduced multilevel topology. The converter is based on the mixture of the two most popular multicell topologies, namely, flying capacitor and cascaded multicell inverter. The new cell provides a high number of output levels, a low number of components, high modularity, and low losses. The results presented in this paper confirm that this new medium-voltage inverter topology is able to reach high-quality output voltages, allowing further advances in modulation techniques and other issues. © 2010 IEEE.
Javadi A.H.,TU Dresden |
Aichelburg C.,University College London
PLoS ONE | Year: 2012
There is strong evidence that magnitudes in different dimensions can interfere. A majority of previous studies on the interaction of temporal magnitudes on numerosity showed no interfering effect, while many studies have reported the interference of numerosity on judgement of temporal magnitudes. We speculated that this one-way interference is confounded by the magnitudes used in the studies. We used a methodology that allowed us to study this interaction reciprocally. Moreover, we selected magnitudes for two dimensions that enabled us to detect their interfering effects. Participants had to either judge which of two successive sets of items was more numerous (numerosity judgement task), or which set of items was presented longer (duration judgement task). We hypothesised that a longer presentation of a set will be judged as being more numerous, and vice versa, a more numerous set will be judged as being presented longer. Results confirmed our hypothesis. A positive correlation between duration of presentation and judged numerosity as well as a positive correlation between the number of items and judged duration of presentation was found. This observation supports the idea that duration and numerosity judgements are not completely independent and implies the existence of (partly) generalised and abstract components in the magnitude representations. © 2012 Javadi, Aichelburg.
Rudolph W.W.,TU Dresden
Dalton Transactions | Year: 2010
Phosphoric acid in water and heavy water has been studied by Raman and infrared spectroscopy over a broad concentration range (0.00873-1.560 mol kg -1) at 23 °C. The vibrational modes of the PO 4 skeleton (C 3v symmetry) of H 3PO 4(aq) and D 3PO 4(D 2O) have been assigned. In addition to the P-O stretching modes a deformation mode has been detected, δPO-H(D) at 1250 and 935 cm -1, respectively. In addition to the modes of the phosphoric acid and heavy phosphoric acid a mode of the dissociation product H 2PO 4 - and D 2PO 4 - has been detected at 1077 cm -1 and 1084 cm -1 respectively. H 3PO 4 and D 3PO 4 is hydrated in aqueous solution which could be verified by Raman spectroscopy following the νPO and ν sP(OH) 3 mode as a function of temperature. These modes show a pronounced temperature dependence inasmuch as νPO shifts to higher wavenumbers with temperature increase and ν sP(OH) 3 to lower wavenumbers. In the range between 300-600 cm -1 the deformation modes have been observed. In very dilute H 3PO 4 solutions however, the dissociation product is the dominant species. The dissociation degree, α for H 3PO 4(aq) and D 3PO 4(D 2O) as a function of dilution has been measured at 23 °C. In these dilute H 3PO 4(aq) and D 3PO 4(D 2O) solutions no spectroscopic features for a dimeric species of the formula H 6P 2O 8 and D 6P 2O 8 could be detected. Quantitative Raman measurements have been carried out to follow the dissociation of H 3PO 4 and D 3PO 4 over a very broad concentration range and also as a function of temperature. From the dissociation data, the pK 1 value for H 3PO 4 has been determined to 2.14(1) and for D 3PO 4 to 2.42(1) at 23 °C. In the temperature interval from 24.5 to 99.7 °C the pK 1 values for H 3PO 4(aq) have been determined and thermodynamic data have been derived. © 2010 The Royal Society of Chemistry.
Reichmann H.,TU Dresden
Parkinsonism and Related Disorders | Year: 2010
Conceptually, continuous dopaminergic stimulation is universally accepted to be the preferred therapeutic strategy to prevent or postpone dyskinesia in Parkinson's disease (PD). l-dopa has a short half-life of 2 hours and causes dyskinesia, whereas dopamine receptor agonists usually have a much longer half-life. Of the latter agents, cabergoline has the longest half-life of 68 hours and is ideal for the prevention of dyskinesia; but this is also true for other dopamine receptor agonists such as ropinirole or pramipexole, which have a shorter half-life of about 6-8 hours. Due to the possible development of valvular fibrosis, cabergoline is, however, only approved as a second-line treatment in PD, and patch technology has therefore gained major interest. So far, rotigotine is the only dopamine receptor agonist available as a patch. There is good evidence that once-daily patch usage provides patients with constant dopaminergic stimulation, and that patches are of equal potency to other oral non-ergot derivatives such as ropinirole and pramipexole. The disadvantages of patches are skin irritation and crystallization of the drug if not kept in the refrigerator. © 2009 Elsevier Ltd. All rights reserved.
Frenzel M.,TU Dresden
Beton- und Stahlbetonbau | Year: 2015
This paper presents analysis methods and design models based on the conventional reinforced concrete design procedure, that are used to determine the nominal capacity of flexural bending of steel reinforced concrete members strengthened with textile reinforcement. The shown computational algorithm allows considering different failure modes such as textile and steel tensile failure, concrete compressive collapse and introduced stress states, which act before the strengthening measure. In addition to an iterative calculation process, two simplified formulas are given to easily calculate the necessary area of reinforcement of strengthened elements under bending. Furthermore, the article provides tables and charts for a simple and practical design calculation. The application of analysis and design methods is demonstrated conclusively on the basis of example calculations. © Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin.
Kunstmann J.,TU Dresden |
Ozdogan C.,Cankaya University |
Quandt A.,University of Greifswald |
Quandt A.,University of Witwatersrand |
Fehske H.,University of Greifswald
Physical Review B - Condensed Matter and Materials Physics | Year: 2011
We critically discuss the stability of edge states and edge magnetism in zigzag edge graphene nanoribbons (ZGNRs). We point out that magnetic edge states might not exist in real systems and show that there are at least three very natural mechanisms-edge reconstruction, edge passivation, and edge closure-which dramatically reduce the effect of edge states in ZGNRs or even totally eliminate them. Even if systems with magnetic edge states could be made, the intrinsic magnetism would not be stable at room temperature. Charge doping and the presence of edge defects further destabilize the intrinsic magnetism of such systems. © 2011 American Physical Society.
Holthausen M.H.,University of Toronto |
Weigand J.J.,TU Dresden
Chemical Society Reviews | Year: 2014
The aim of this review is to provide a comprehensive view of the chemistry of cationic polyphosphorus cages. The synthetic protocols established for their preparation, which are all based on the functionalization of P4, and their intriguing follow-up chemistry are highlighted. In addition, this review intends to foster the interest of the inorganic, organic, catalytic and material oriented chemical communities in the versatile field of polyphosphorus cage compounds. In the long term, this is envisioned to contribute to the development of new synthetic procedures for the functionalization of P4 and its transformation into (organo-)phosphorus compounds and materials of added value. © 2014 the Partner Organisations.
Froyland G.,University of New South Wales |
Padberg-Gehle K.,TU Dresden
Chaos | Year: 2015
We present a numerical method to identify regions of phase space that are approximately retained in a mobile compact neighbourhood over a finite time duration. Our approach is based on spatio-temporal clustering of trajectory data. The main advantages of the approach are the ability to produce useful results (i) when there are relatively few trajectories and (ii) when there are gaps in observation of the trajectories as can occur with real data. The method is easy to implement, works in any dimension, and is fast to run. © 2015 AIP Publishing LLC.
Treiber M.,TU Dresden |
Kanagaraj V.,Technion - Israel Institute of Technology
Physica A: Statistical Mechanics and its Applications | Year: 2015
When simulating trajectories by integrating time-continuous car-following models, standard integration schemes such as the fourth-order Runge-Kutta method (RK4) are rarely used while the simple Euler method is popular among researchers. We compare four explicit methods both analytically and numerically: Euler's method, ballistic update, Heun's method (trapezoidal rule), and the standard RK4. As performance metrics, we plot the global discretization error as a function of the numerical complexity. We tested the methods on several time-continuous car-following models in several multi-vehicle simulation scenarios with and without discontinuities such as stops or a discontinuous behavior of an external leader. We find that the theoretical advantage of RK4 (consistency order 4) only plays a role if both the acceleration function of the model and the trajectory of the leader are sufficiently often differentiable. Otherwise, we obtain lower (and often fractional) consistency orders. Although, to our knowledge, Heun's method has never been used for integrating car-following models, it turns out to be the best scheme for many practical situations. The ballistic update always prevails over Euler's method although both are of first order. © 2014 Elsevier B.V. All rights reserved.
Gall J.,Max Planck Institute for Computer Science |
Rosenhahn B.,Max Planck Institute for Computer Science |
Brox T.,TU Dresden |
Seidel H.-P.,Max Planck Institute for Computer Science
International Journal of Computer Vision | Year: 2010
Local optimization and filtering have been widely applied to model-based 3D human motion capture. Global stochastic optimization has recently been proposed as promising alternative solution for tracking and initialization. In order to benefit from optimization and filtering, we introduce a multi-layer framework that combines stochastic optimization, filtering, and local optimization. While the first layer relies on interacting simulated annealing and some weak prior information on physical constraints, the second layer refines the estimates by filtering and local optimization such that the accuracy is increased and ambiguities are resolved over time without imposing restrictions on the dynamics. In our experimental evaluation, we demonstrate the significant improvements of the multi-layer framework and provide quantitative 3D pose tracking results for the complete HumanEva-II dataset. The paper further comprises a comparison of global stochastic optimization with particle filtering, annealed particle filtering, and local optimization.
Schaller J.,TU Dresden
Ecological Engineering | Year: 2013
Wetlands are well known for water treatment and as a sink for elements (e.g. metals/metalloids). The elements are mainly fixed by sediments, microbial biofilms and plants, whereas the organic part of the sediment has a potential important role. These organic sediments underlie the process of organic matter decomposition, which proceeds in the three distinct steps of leaching, microbial conditioning and fragmentation by aquatic fauna. The effect of organic matter fragmentation on elemental fixation was shown previously only under neutral pH conditions. Hence, a batch experiment was conducted to assess the effect of invertebrate shredder on elemental accumulation during litter decay under low acidic conditions. Here it is shown that this fragmentation of the organic material by aquatic fauna enhances the elemental fixation potential of the organic sediments significantly, also under low acidic conditions. During the process of fragmentation the surface area of the organic matter increases by increasing amount of smaller particles. This in turn results in higher adsorption capacity of a larger amount of growing biofilm enhancing the surface even more (heterotrophic microorganisms). The growing biofilm (periphyton) with its larger surface area and hence more functional groups result in higher elemental fixation. Therefore, invertebrate shredders as ecosystem engineers enhance the capability for elemental fixation by fragmentation of organic matter, which is an important process in wetlands ecosystems usable in a broad pH range. © 2012 Elsevier B.V..
Tanaka E.,TU Dresden |
Reddien P.,Howard Hughes Medical Institute
Developmental Cell | Year: 2011
The ability of animals to regenerate missing parts is a dramatic and poorly understood aspect of biology. The sources of new cells for these regenerative phenomena have been sought for decades. Recent advances involving cell fate tracking in complex tissues have shed new light on the cellular underpinnings of regeneration in Hydra, planarians, zebrafish, Xenopus, and Axolotl. Planarians accomplish regeneration with use of adult pluripotent stem cells, whereas several vertebrates utilize a collection of lineage-restricted progenitors from different tissues. Together, an array of cellular strategies-from pluripotent stem cells to tissue-specific stem cells and dedifferentiation-are utilized for regeneration. © 2011 Elsevier Inc.
Bigall N.C.,Italian Institute of Technology |
Eychmuller A.,TU Dresden
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences | Year: 2010
This article highlights our recent work concerning the synthesis of metal nanoparticles and their non-ordered superstructures. After a short introduction, the basic synthetic procedures are explained for the nanoparticles used for the assemblies. Furthermore, a fabrication method is itemized for very monodisperse platinum nanoparticles in aqueous solution ranging in diameter from 10 to 100 nm showing distinct optical properties. The next section deals with the synthesis of non-ordered hydro-and aerogels from the asprepared sols. Very light large surface materials from gold, silver, platinum and gold-silver and platinum-silver sols can be fabricated with the given method. Another way to ultralight superstructures of noble metal nanoparticles using fungi as templates is described in the third section. Although fungi grow inside the colloidal solutions they can assemble the nanoparticles onto their surfaces. These hybrid systems are thus extremely interesting supported superstructures for applications in heterogeneous catalysis, since the numbers of nanoparticles on the fungus can easily be tuned, and the fabrication process is cost-effective, environmentally friendly and the organic templates can be easily removed by simple combustion for regaining the noble metal. © 2010 The Royal Society.
Bottcher B.,TU Dresden
PLoS ONE | Year: 2010
We present a simple construction method for Feller processes and a framework for the generation of sample paths of Feller processes. The construction is based on state space dependent mixing of Lévy processes. Brownian Motion is one of the most frequently used continuous time Markov processes in applications. In recent years also Lévy processes, of which Brownian Motion is a special case, have become increasingly popular. Lévy processes are spatially homogeneous, but empirical data often suggest the use of spatially inhomogeneous processes. Thus it seems necessary to go to the next level of generalization: Feller processes. These include Lévy processes and in particular Brownian motion as special cases but allow spatial inhomogeneities. Many properties of Feller processes are known, but proving the very existence is, in general, very technical. Moreover, an applicable framework for the generation of sample paths of a Feller process was missing. We explain, with practitioners in mind, how to overcome both of these obstacles. In particular our simulation technique allows to apply Monte Carlo methods to Feller processes. © 2010 Björn Böttcher.
Elsner B.,TU Dresden
The Cochrane database of systematic reviews | Year: 2013
Stroke is one of the leading causes of disability worldwide. Aphasia among stroke survivors is common. Current speech and language therapy (SLT) strategies have only limited effectiveness in improving aphasia. A possible adjunct to SLT for improving SLT outcomes might be non-invasive brain stimulation by transcranial direct current stimulation (tDCS) to modulate cortical excitability and hence to improve aphasia. To assess the effects of tDCS for improving aphasia in patients after stroke. We searched the Cochrane Stroke Group Trials Register (April 2013), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, March 2012), MEDLINE (1948 to March 2012), EMBASE (1980 to March 2012), CINAHL (1982 to March 2012), AMED (1985 to April 2012), Science Citation Index (1899 to April 2012) and seven additional databases. We also searched trials registers and reference lists, handsearched conference proceedings and contacted authors and equipment manufacturers. We included only randomised controlled trials (RCTs) and randomised controlled cross-over trials (from which we only analysed the first period as a parallel group design) comparing tDCS versus control in adults with aphasia due to stroke. Two review authors independently assessed trial quality and extracted the data. If necessary, we contacted study authors for additional information. We collected information on dropouts and adverse events from the trials. We included five trials involving 54 participants. None of the included studies used any formal outcome measure for measuring functional communication, that is measuring aphasia in a real-life communicative setting. All five trials measured correct picture naming as a surrogate for aphasia. There was no evidence that tDCS enhanced SLT outcomes. No adverse events were reported and the proportion of dropouts was comparable between groups. Currently there is no evidence of the effectiveness of tDCS (anodal tDCS, cathodal tDCS) versus control (sham tDCS). However, it appears that cathodal tDCS over the non-lesioned hemisphere might be the most promising approach.
Elsner B.,TU Dresden
The Cochrane database of systematic reviews | Year: 2013
Stroke is one of the leading causes of disability worldwide. Functional impairment resulting in poor performance in activities of daily living (ADLs) among stroke survivors is common. Current rehabilitation approaches have limited effectiveness in improving ADL performance and function after stroke, but a possible adjunct to stroke rehabilitation might be non-invasive brain stimulation by transcranial direct current stimulation (tDCS) to modulate cortical excitability and hence to improve ADL performance and function. To assess the effects of tDCS on generic activities of daily living (ADLs) and motor function in people with stroke. We searched the Cochrane Stroke Group Trials Register (March 2013), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, May 2013), MEDLINE (1948 to May 2013), EMBASE (1980 to May 2013), CINAHL (1982 to May 2013), AMED (1985 to May 2013), Science Citation Index (1899 to May 2013) and four additional databases. In an effort to identify further published, unpublished and ongoing trials, we searched trials registers and reference lists, handsearched conference proceedings and contacted authors and equipment manufacturers. We included only randomised controlled trials (RCTs) and randomised controlled cross-over trials (from which we analysed only the first period as a parallel-group design) that compared tDCS versus control in adults with stroke for improving ADL performance and function. Two review authors independently assessed trial quality (JM and MP) and extracted data (BE and JM). If necessary, we contacted study authors to ask for additional information. We collected information on dropouts and adverse events from the trial reports. We included 15 studies involving a total of 455 participants. Analysis of six studies involving 326 participants regarding our primary outcome, ADL, showed no evidence of an effect in favour of tDCS at the end of the intervention phase (mean difference (MD) 5.31 Barthel Index (BI) points; 95% confidence interval (CI) -0.52 to 11.14; inverse variance method with random-effects model), whereas at follow-up (MD 11.13 BI points; 95% CI 2.89 to 19.37; inverse variance method with random-effects model), we found evidence of an effect. However, the confidence intervals were wide and the effect was not sustained when only studies with low risk of bias were included. For our secondary outcome, upper limb function, we analysed eight trials with 358 participants, which showed evidence of an effect in favour of tDCS at the end of the intervention phase (MD 3.45 Upper Extremity Fugl-Meyer Score points (UE-FM points); 95% CI 1.24 to 5.67; inverse variance method with random-effects model) but not at the end of follow-up three months after the intervention (MD 9.23 UE-FM points; 95% CI -13.47 to 31.94; inverse variance method with random-effects model). These results were sensitive to inclusion of studies at high risk of bias. Adverse events were reported and the proportions of dropouts and adverse events were comparable between groups (risk difference (RD) 0.00; 95% CI -0.02 to 0.03; Mantel-Haenszel method with random-effects model). At the moment, evidence of very low to low quality is available on the effectiveness of tDCS (anodal/cathodal/dual) versus control (sham/any other intervention) for improving ADL performance and function after stroke. Future research should investigate the effects of tDCS on lower limb function and should address methodological issues by routinely reporting data on adverse events and dropouts and allocation concealment, and by performing intention-to-treat analyses.
Elstner M.,Karlsruhe Institute of Technology |
Seifert G.,TU Dresden
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences | Year: 2014
This paper reviews the basic principles of the density-functional tight-binding (DFTB) method, which is based on density-functional theory as formulated by Hohenberg, Kohn and Sham (KSDFT). DFTB consists of a series of models that are derived from a Taylor series expansion of the KS-DFT total energy. In the lowest order (DFTB1), densities and potentials are written as superpositions of atomic densities and potentials. The Kohn-Sham orbitals are then expanded to a set of localized atom-centred functions, which are obtained for spherical symmetric spin-unpolarized neutral atoms self-consistently. The whole Hamilton and overlap matrices contain one- and two-centre contributions only. Therefore, they can be calculated and tabulated in advance as functions of the distance between atomic pairs. The second contributions to DFTB1, the DFT double counting terms, are summarized together with nuclear repulsion energy terms and can be rewritten as the sum of pairwise repulsive terms. The second-order (DFTB2) and third-order (DFTB3) terms in the energy expansion correspond to a selfconsistent representation, where the deviation of the ground-state density from the reference density is represented by charge monopoles only. This leads to a computationally efficient representation in terms of atomic charges (Mulliken), chemical hardness (Hubbard) parameters and scaled Coulomb laws. Therefore, no additional adjustable parameters enter the DFTB2 and DFTB3 formalism. The handling of parameters, the efficiency, the performance and extensions of DFTB are briefly discussed. © 2014 The Author(s) Published by the Royal Society. All rights reserved.
Muller M.,Leibniz Institute of Polymer Research |
Muller M.,TU Dresden
Advances in Polymer Science | Year: 2014
This contribution reviews polyelectrolyte (PEL) complex (PEC) nanoparticles prepared by mixing solutions of oppositely charged PELs, with special focus on the regulation of their size and shape by PEL structural and media parameters and on their pharmaceutical applications. Experimental and simulation evidence indicates that salt and PEL concentration, pH, mixing ratio and order, PEL molecular weight and topology are useful parameters for regulation of the size and internal structure of spherical PEC nanoparticles. Experimental and theoretical data are presented to show that PEL flexibility and stiffness are able to influence and even control PEC nanoparticle shape. Finally, the options, advantages, and challenges of dispersed PEC particles for pharmaceutical applications are outlined, emphasizing the uptake and release properties towards proteins and drugs and the interaction of these nanoparticles with cells. © Springer-Verlag Berlin Heidelberg 2012.
Altman E.,Weizmann Institute of Science |
Sieberer L.M.,University of Innsbruck |
Chen L.,China University of Mining and Technology |
Diehl S.,University of Innsbruck |
And 2 more authors.
Physical Review X | Year: 2015
Fluids of exciton polaritons, excitations of two-dimensional quantum wells in optical cavities, show collective phenomena akin to Bose condensation. However, a fundamental difference from standard condensates stems from the finite lifetime of these excitations, which necessitates continuous driving to maintain a steady state. A basic question is whether a two-dimensional condensate with long-range algebraic correlations can exist under these nonequilibrium conditions. Here, we show that such driven two-dimensional Bose systems cannot exhibit algebraic superfluid order except in low-symmetry, strongly anisotropic systems. Our result implies, in particular, that recent apparent evidence for Bose condensation of exciton polaritons must be an intermediate-scale crossover phenomenon, while the true long-distance correlations fall off exponentially. We obtain these results through a mapping of the long-wavelength condensate dynamics onto the anisotropic Kardar-Parisi-Zhang equation.
Paufler P.,TU Dresden
Intermetallics | Year: 2011
Initiated by Gustav E.R. Schulze, pioneering experimental and theoretical work on Laves phases was done in Dresden/East Germany after World War II, which was then part of the German Democratic Republic GDR behind the former Iron Curtain. Due to Cold War restrictions, many of the results have not become known to the West. The present overview gives an insight into the compounds dealt with, the properties measured, the features calculated and the conclusions drawn. Starting with concepts of crystal chemistry, like inflated coordination number or maximum density, rules for the formation of Laves phases have been established. One focus of the experimental work was the impact of deviation from stoichiometric composition upon structure and physical properties. Mutual substitution of A and B atoms in AB2 phases was identified as prevalent constitutional defect. Apart from structural studies employing X-ray and neutron diffraction, various physical properties of selected members have been measured, like electrical and thermal conductivity, heat capacity, magnetic susceptibility, thermal expansion, diffusion coefficient, and optical constants. Computations of electron and phonon spectra of selected Laves phases from first principles helped to correct the naïve simple-metal-view upon those metallic solids and to understand physical properties more thoroughly. As another main field of research, studies of the plasticity and real structure of certain Laves phases are reviewed. Macroscopic stress-strain behaviour has been broken down to dislocation dynamics using Orowan's equation. An important role of Peierls stress as obstacle to dislocation movement has been concluded from that. In addition, changes of dislocation density and geometry within the range of homogeneity were characterized quantitatively. Alloy softening was found with off-stoichiometric compounds due to an elevated density of grown-in dislocations. © 2010 Elsevier Ltd. All rights reserved.
Kessler R.C.,Harvard University |
Petukhova M.,Harvard University |
Sampson N.A.,Harvard University |
Zaslavsky A.M.,Harvard University |
Wittchen H.-U.,TU Dresden
International Journal of Methods in Psychiatric Research | Year: 2012
Estimates of 12-month and lifetime prevalence and of lifetime morbid risk (LMR) of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR) anxiety and mood disorders are presented based on US epidemiological surveys among people aged 13+. The presentation is designed for use in the upcoming DSM-5 manual to provide more coherent estimates than would otherwise be available. Prevalence estimates are presented for the age groups proposed by DSM-5 workgroups as the most useful to consider for policy planning purposes. The LMR/12-month prevalence estimates ranked by frequency are as follows: major depressive episode: 29.9%/8.6%; specific phobia: 18.4/12.1%; social phobia: 13.0/7.4%; post-traumatic stress disorder: 10.1/3.7%; generalized anxiety disorder: 9.0/2.0%; separation anxiety disorder: 8.7/1.2%; panic disorder: 6.8%/2.4%; bipolar disorder: 4.1/1.8%; agoraphobia: 3.7/1.7%; obsessive-compulsive disorder: 2.7/1.2. Four broad patterns of results are most noteworthy: first, that the most common (lifetime prevalence/morbid risk) lifetime anxiety-mood disorders in the United States are major depression (16.6/29.9%), specific phobia (15.6/18.4%), and social phobia (10.7/13.0%) and the least common are agoraphobia (2.5/3.7%) and obsessive-compulsive disorder (2.3/2.7%); second, that the anxiety-mood disorders with the earlier median ages-of-onset are phobias and separation anxiety disorder (ages 15-17) and those with the latest are panic disorder, major depression, and generalized anxiety disorder (ages 23-30); third, that LMR is considerably higher than lifetime prevalence for most anxiety-mood disorders, although the magnitude of this difference is much higher for disorders with later than earlier ages-of-onset; and fourth, that the ratio of 12-month to lifetime prevalence, roughly characterizing persistence, varies meaningfully in ways consistent with independent evidence about differential persistence of these disorders. © 2012 John Wiley & Sons, Ltd..
Muller F.,TU Dresden
Cryptogamie, Bryologie | Year: 2011
Euptychium piliferum Frank Müll. is described and illustrated. The species is most closely related to E. cuspidatum. Its distinctive features include leaves with piliferous acumina 0.7-1.0 mm long, a leaf length/width ratio of 4.5-6:l, a leaf length of 3.4-4.0 mm, leaf margins entire to weakly serrulate in the basal half, and strongly incrassate and porose leaf cells. A revised key to the species of the genus Euptychium is provided. © 2011 Adac. Tous droits réservés.
Leviston Z.,CSIRO |
Walker I.,CSIRO |
Morwinski S.,TU Dresden
Nature Climate Change | Year: 2013
Political and media debate on the existence and causes of climate change has become increasingly factious in several western countries, often resting on claims and counter-claims about what most citizens really think. There are several well-established phenomena in psychology about how people perceive the prevalence of opinions, including the false consensus effect (a tendency to overestimate how common one's 'own' opinion is) and pluralistic ignorance (where most people privately reject an opinion, but assume incorrectly that most others accept it). We investigated these biases in people's opinions about the existence and causes of climate change. In two surveys conducted 12 months apart in Australia (n = 5,036; n = 5,030), respondents were asked their own opinion about the nature of climate change, and then asked to estimate levels of opinion among the general population. We demonstrate that opinions about climate change are subject to strong false consensus effects, that people grossly overestimate the numbers of people who reject the existence of climate change in the broader community, and that people with high false consensus bias are less likely to change their opinions. © 2013 Macmillan Publishers Limited. All rights reserved.
Karrasch D.,TU Dresden
Physica D: Nonlinear Phenomena | Year: 2012
In this brief note, we state the main result of Haller [G. Haller, A variational theory of hyperbolic Lagrangian coherent structures, Physica D 240 (7) (2011) 574-598] on a variational approach to Lagrangian coherent structures (LCSs) more precisely by adding an extra assumption to ensure the existence of the involved derivatives. Under that assumption we further simplify the positive definiteness condition on the matrix L, which is also referred to as "hyperbolicity test", to a condition on the second-order directional derivative of the largest eigenvalue. This extends an observation in the two-dimensional case made by Farazmand and Haller [M. Farazmand, G. Haller, Erratum and addendum to "A variational theory of hyperbolic Lagrangian coherent structures [Physica D 240 (2011) 574-598]", Physica D 241 (4) (2012) 439-441] on the simplified detection of LCS from finite-time Lyapunov exponent ridges. © 2012 Elsevier B.V. All rights reserved.
Froyland G.,University of New South Wales |
Padberg-Gehle K.,TU Dresden
Physica D: Nonlinear Phenomena | Year: 2012
Transport and mixing processes in dynamical systems are often difficult to study analytically and therefore a variety of numerical methods have been developed. Finite-time Lyapunov exponents (FTLEs) or related stretching indicators are frequently used as a means to estimate transport barriers. Alternatively, eigenvectors, singular vectors, or Oseledets vectors of numerical transfer operators find almost-invariant sets, finite-time coherent sets, or time-asymptotic coherent sets, respectively, which are minimally dispersed under the dynamics. While these families of approaches (geometric FTLEs and the probabilistic transfer operator) often give compatible results, a formal link is still missing; here we present a small step towards providing a mathematical link. We propose a new entropy-based methodology for estimating finite-time expansive behaviour along trajectories in autonomous and nonautonomous dynamical systems. We introduce the finite-time entropy (FTE) field as a simple and flexible way to capture nonlinear stretching directly from the entropy growth experienced by a small localised density evolved by the transfer operator. The FTE construction elucidates in a straightforward way the connection between the evolution of probability densities and the local stretching experienced. We develop an extremely simple and numerically efficient method of constructing an estimate of the FTE field. The FTE field is instantaneously calculable from a numerical transfer operator - a transition matrix of conditional probabilities that describes a discretised version of the dynamical system; once one has such a transition matrix, the FTE field may be computed "for free". We also show (i) how to avoid long time integrations in autonomous and time-periodic systems, (ii) how to perform backward time computations by a fast matrix manipulation rather than backward time integration, and (iii) how to easily employ adaptive methods to focus on high-value FTE regions. © 2012 Elsevier B.V. All rights reserved.
Dasgupta S.K.,Baylor College of Medicine |
Le A.,Baylor College of Medicine |
Chavakis T.,TU Dresden |
Rumbaut R.E.,Baylor College of Medicine |
Thiagarajan P.,Baylor College of Medicine
Circulation | Year: 2012
Background: Phosphatidylserine-expressing microparticles circulate in blood with a short half-life of 10 minutes. We tested the role of an endothelium-derived phosphatidylserine-binding opsonin, developmental endothelial locus-1 (Del-1), in the uptake of platelet microparticles. Methods and Results-Cultured human umbilical vein and microvascular endothelial cells avidly engulf BODIPY (4,4-difluoro-4-bora-3a,4a-diaza-s-indacene)-maleimide- labeled platelet microparticles. Microparticle uptake was inhibited by a monoclonal antibody to Del-1 (P=0.027) and by annexin A5 (P=0.027), abciximab (P=0.027), a monoclonal antibody to integrin αVβ3 (P=0.027), and chlorpromazine (P=0.027). These results suggest that Del-1 mediates phosphatidylserine- and integrin-dependent endothelial uptake of microparticles by endocytosis. To assess the in vivo significance, we infused fluorescent platelet microparticles into the inferior vena cava of mice and harvested endothelial cells from the pulmonary and systemic circulation. Compared with their wild-type littermates, Del-1- deficient mice had decreased uptake in endothelial cells in lung (3.07±1.9 versus 1.09±1.3, P=0.02) and liver (2.85±1.1 versus 1.35±0.92, P=0.01). Furthermore, after endotoxin administration, Del-1- deficient mice displayed an increase in the level of microparticles compared with wild-type mice (P=0.02). Conclusions-These studies show a physiological role for Del-1 in the clearance of phosphatidylserine-expressing microparticles by endothelium. (Circulation. 2012;125:1664-1672.) © 2012 American Heart Association, Inc.
Mignard F.,University of Nice Sophia Antipolis |
Klioner S.,TU Dresden
Astronomy and Astrophysics | Year: 2012
Aims. We compare stellar catalogues with position and proper motion components using a decomposition on a set of orthogonal vector spherical harmonics. We aim to show the theoretical and practical advantages of this technique as a result of invariance properties and the independence of the decomposition from a prior model. Methods. We describe the mathematical principles used to perform the spectral decomposition, evaluate the level of significance of the multipolar components, and examine the transformation properties under space rotation. Results. The principles are illustrated with a characterisation of systematic effects in the FK5 catalogue compared to Hipparcos and with an application to extraction of the rotation and dipole acceleration in the astrometric solution of QSOs expected from Gaia. © 2012 ESO.
Bauer A.,TU Dresden
Cochrane database of systematic reviews (Online) | Year: 2010
BACKGROUND: Occupational irritant hand dermatitis (OIHD) is an important cause of discomfort in the working population. Different preventive measures are in place but it is not clear how effective these are. OBJECTIVES: To assess the effect of interventions for preventing OIHD in healthy people who work in occupations where the skin is at risk of damage. SEARCH STRATEGY: In May 2010, we searched the Cochrane Skin Group Specialised Register, the Cochrane Central Register of Controlled Trials in The Cochrane Library, MEDLlNE and EMBASE. Conference proceedings, and ongoing trials registers were also searched. SELECTION CRITERIA: Randomised controlled trials (RCTs) studying the effectiveness of barrier creams, moisturisers, gloves, complex educational interventions, and other interventions for the prevention of OIHD. DATA COLLECTION AND ANALYSIS: Two authors independently assessed the trials and extracted data. MAIN RESULTS: Four RCTs involving 894 participants from different occupations were included. The primary outcome was numbers of new cases.One large RCT of 708 print and dye workers compared 2 barrier creams (containing silicone or hydrocarbon) versus no intervention. Fewer workers using barrier creams developed OIHD than those who did not (39.9% versus 45%, (OR 0.75, 95% CI 0.53 to 1.07. P = 0.11) but this was not statistically significant.In 1 RCT of 54 metal workers less developed OIHD when using an after work emollient or a barrier cream compared to no intervention. There was no statistical difference between the groups at different times of follow-up.One RCT of 111 cleaners and kitchen workers compared a moisturiser (Locobase) versus no intervention using a cross-over design. While using the moisturiser no participant developed OIHD. During the control period with no skin treatment, 19 (20.4%) out of 93 participants developed OIHD.One RCT of 21 hairdressers compared a barrier cream containing aluminium chlorohydrate (Excipial protect) versus its vehicle. No participant developed OIHD while the products were used.Only limited side-effects such as transient itching, stinging, and dryness were reported for the interventions. AUTHORS' CONCLUSIONS: Although the findings of this review were generally positive, no statistical significance was reached. We conclude that at present there is insufficient evidence for the effectiveness of most of the interventions used in the primary prevention of OIHD. This does not mean that current measures are necessarily ineffective, as the limited studies to date have been rather small and of poor quality. Larger well designed RCTs are now needed in different workplaces to establish the effectiveness of various preventative strategies.
Ehrlich H.,TU Dresden
International Geology Review | Year: 2010
Biomineralized structures and tissues are composites, containing a biologically produced organic matrix and nano- or microscale amorphous or crystalline minerals. Two main examples of organic matrices - the amino-polysaccharide chitin and the asymmetric protein collagen - are presented and discussed as the basic structural modules and organo-templates for calcium and silica biomineralization in nature. Both serve as templates, providing preferential sites for nucleation and controlling the location and orientation of mineral phases. Here, for the first time, chitin and collagen are analysed from evolutionary, structural, and functional points of view with respect to their templating properties in calcification and silicification phenomena, using both in vivo and in vitro data. It is proposed that these biopolymers be characterized as fundamental templates in biomineralization, inasmuch as they are very ancient from an evolutionary point of view, common to many species and biological systems with a global distribution. The two polymers also exhibit very similar hierarchical structural organizations, in spite of the possible alternatives they provide in chemical nature and origin. In addition, the phenomenon of multi-phase mineralization - where two minerals, amorphous and crystalline CaCO3, form from one biomolecule, chitin - is also described, analysed, and discussed for the first time. © 2010 Taylor & Francis.
Knappe S.,TU Dresden
European child & adolescent psychiatry | Year: 2010
Within the last decade, social anxiety disorder (SAD) has been identified as a highly prevalent and burdensome disorder. Both the characterization of its symptomatology and effective treatment options are widely documented. Studies particularly indicate that SAD aggregates in families and has its onset in early adolescence. Given the family as an important context for children's cognitive, emotional and behavioural development, familial risk factors could be expected to significantly contribute to the reliable detection of populations at risk for SAD. Reviewing studies on familial risk factors for SAD argues for the importance of parental psychopathology and unfavourable family environment, but also denotes to several shortcomings such as cross-sectional designs, short follow-up periods, diverging methodologies and the focus on isolated factors. Using a prospective longitudinal study that covers the high-risk period for SAD, including a broader spectrum of putative risk factors may help to overcome many of the methodological limitations. This review sets out to develop a more family-oriented approach for predicting the onset and maintenance of SAD that may be fruitful to derive targeted prevention and early intervention in SAD.
Maas H.-G.,TU Dresden
Bautechnik | Year: 2012
On the potential of photogrammetric techniques in civil engineering material testing Photogrammetry is a technique to derive metric information from images with high precision and reliability. The paper presents the fundamentals and some application examples of close range photogrammetry in civil engineering material testing. A clear advantage of photogrammetric techniques is in the fact that it allows for simultaneous measurements at a large number of positions in an image. Processing stereoscopic images, 3D object information can be obtained. Subpixel accuracy image processing operators together with strict geometric sensor modeling allows for obtaining high accuracies in fully automatic measurement systems based on off-the-shelf camera components. Copyright © 2012 Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin.
Mullers E.,Karolinska Institutet |
Mullers E.,TU Dresden
Viruses | Year: 2013
Gag proteins play an important role in many stages of the retroviral replication cycle. They orchestrate viral assembly, interact with numerous host cell proteins, engage in regulation of viral gene expression, and provide the main driving force for virus intracellular trafficking and budding. Foamy Viruses (FV), also known as spumaviruses, display a number of unique features among retroviruses. Many of these features can be attributed to their Gag proteins. FV Gag proteins lack characteristic orthoretroviral domains like membrane-binding domains (M domains), the major homology region (MHR), and the hallmark Cys-His motifs. In contrast, they contain several distinct domains such as the essential Gag-Env interaction domain and the glycine and arginine rich boxes (GR boxes). Furthermore, FV Gag only undergoes limited maturation and follows an unusual pathway for nuclear translocation. This review summarizes the known FV Gag domains and motifs and their functions. In particular, it provides an overview of the unique structural and functional properties that distinguish FV Gag proteins from orthoretroviral Gag proteins. © 2013 by the authors; licensee MDPI, Basel, Switzerland.
Hermsdorf D.,TU Dresden
Radiation Measurements | Year: 2011
In the paper the registration sensitivity of light swift charged projectiles in Solid State Nuclear Track Detectors (SSNTD) of type CR-39 is investigated. Comparing experimental data and their interpretation in terms of empirical and semi-empirical models, the influence of physics aspects of particle transport in solids on the registration sensitivity is studied. Taking into account the energy loss along the particle trajectory by particle-matter interaction the basic properties of the sensitivity functions for registration of protons, deuterons and ions of 4He, 7Li, 11B, 12C, 14N and 16O are described. However, a unique interpretation in terms of physics of particle penetration into a solid cannot be achieved. Deviations from fundamental physics are highlighted and discussed. © 2011 Elsevier Ltd. All rights reserved.
Zschocke S.,TU Dresden
Classical and Quantum Gravity | Year: 2011
A generalized lens equation for weak gravitational fields of Schwarzschild metric and valid for finite distances of source and observer from the light deflecting body is suggested. The magnitude of neglected terms in the generalized lens equation is estimated to be smaller than or equal to 15π/4 m2/d′2, where m is the Schwarzschild radius of the massive body and d′ is Chandrasekhar's impact parameter. The main applications of this generalized lens equation are extreme astrometrical configurations, where the standard post-Newtonian approach as well as the classical lens equation cannot be applied. It is shown that in the appropriate limits, the proposed lens equation yields the known post-Newtonian terms, 'enhanced' post-post-Newtonian terms and the classical lens equation, thus providing a link between both these essential approaches for determining the light deflection. © 2011 IOP Publishing Ltd.
Deegen P.,TU Dresden
Forest Policy and Economics | Year: 2013
Forestry is not an entity. Forestry includes countless and complex types of human interactions concerning forests. Humans have found complex and nearly endlessly diverse institutional structures. Differences in the results of interactions are often caused by different institutional structures. Economic theories as explanations of human interactions are not detached from institutional structures. Their predictions are only valid in these institutional settings.In this paper, existent economic theories and models of forestry, like the Faustmann approach, the public choice school, Ostrom's "Governing the commons", and others will be systematised according to their underlying institutional structures. In a second step, the interrelations among these approaches will be studied. From this point of view, some identification of unanalysed or less analysed areas of forestry are possible which finally allow some comments for future research in forestry economics.For solving these aims, a classification of the diverse institutional structures is necessary which will be developed stepwise. I will introduce the two independent characteristics "range of publicness in sub-constitutional contracts" and "forms of moral order". The first characteristic is distinguished into the two institutional contractual types "politics" and "markets", the second characteristic is distinguished into the "external" and "extended" moral order. © 2013 Elsevier B.V.
Siedel H.,TU Dresden
Environmental Earth Sciences | Year: 2013
A record of mortar and salt analyses from the last 20 years on various monuments in Saxony demonstrates the close relation between the occurrence of magnesium sulphate salts and the use of dolomitic lime mortars in a regional frame. The regional distribution scheme of dolomitic lime in historic mortars depends on the geological setting of the territory, i.e. the natural occurrence of dolomite deposits. Sulphation of these mortars with the formation of magnesium sulphate and gypsum is mainly due to environmental pollution, as can be shown by sulphur stable isotope analyses. Exposure of the sulphated mortar surfaces to rain leads to the preferential dissolution and advective transport of the novel formed magnesium sulphate salts, which effloresce or subfloresce on the mortar surface or can be accumulated in the structure of adjoining porous building materials like natural stones. These processes may cause severe damages in mortars by the weakening of the binder and in porous stones by salt crystallisation of phases like epsomite and hexahydrite. © 2012 Springer-Verlag Berlin Heidelberg.
Rudolph W.W.,TU Dresden |
Irmer G.,TU Bergakademie Freiberg
Dalton Transactions | Year: 2013
Raman spectroscopic measurements have been performed on aqueous solutions of Mn(ClO4)2, MnCl2, MnBr2, and Mn(NO3)2 in the terahertz region (40-600 cm-1) and to wavenumbers up to 4200 cm-1 employing an absorption gap in these light pink coloured solutions. In Mn(ClO4)2 solutions of water and heavy water, the hexahydrate and its deuterate, [Mn(OH2)6]2+ and [Mn(OD2) 6]2+, were characterized as showing a very weak, strongly polarized band at 354 cm-1 and 338 cm-1, respectively. These modes were assigned to ν1 MnO6 of [Mn(OH 2)6]2+ and [Mn(OD2) 6]2+. In Mn(NO3)2(aq), the undisturbed mode at 354 cm-1, representative of manganese hexahydrate, was also detected in dilute solutions up to ∼3 mol L -1 and no sign of nitrato complex formation could be obtained. In fairly dilute MnCl2(aq) up to ∼1.5 mol L-1 the hexaaqua ions were identified but in concentrated solutions, chloro-complexes of Mn2+ were detected in the form of [Mn(OH2) 6-nCln](+2-n) with n equal to one or two. In MnBr2(aq) a comparable picture to the one in MnCl2(aq) could be obtained. Density functional theory (DFT) calculations on Mn 2+ water clusters were carried out to optimize the geometry and calculate the frequencies of the [Mn(OH2)6]2+ cluster. For this purpose an unrestricted B3LYP functional was used with a triple-ζ basis set 6-311+G(d,p). In order to include the hydration effects around the [Mn(OH2)6]2+, a continuum model approach was employed where the solvent is described by a structureless dielectric polarizable continuum using the Polarizable Continuum Model of Solvation (PCM). The gas phase cluster of [Mn(OH2)6] 2+ led to lower MnO6 frequencies compared to the measured ones. A second, much larger cluster model, with 18 water molecules containing 6 waters in the first shell and an explicit second hydration shell, [Mn(OH 2)6(OH2)12]2+, was modelled. Again, the cluster in vacuo and the cluster surrounded by a structureless polarizable continuum were considered. The larger cluster including the polarizable continuum gives the most realistic frequency value of ν1 MnO6 and the other MnO6 skeleton modes. The hydration enthalpy, ΔHhyd(l) at 298 K, of [Mn(OH 2)6]2+(aq) was calculated by applying a Born-Haber cycle and correcting for the heat of vaporization, ΔH vap, of water and the solvation enthalpy, ΔHsolv, released by transferring the gas phase cluster into the solution. The theoretical hydration enthalpy is in fair agreement with the measured hydration enthalpy. © 2013 The Royal Society of Chemistry.
Justice M.J.,Baylor College of Medicine |
Siracusa L.D.,Thomas Jefferson University |
Stewart A.F.,TU Dresden
DMM Disease Models and Mechanisms | Year: 2011
The mouse is the leading organism for disease research. A rich resource of genetic variation occurs naturally in inbred and special strains owing to spontaneous mutations. However, one can also obtain desired gene mutations by using the following processes: targeted mutations that eliminate function in the whole organism or in a specific tissue; forward genetic screens using chemicals or transposons; or the introduction of exogenous transgenes as DNAs, bacterial artificial chromosomes (BACs) or reporter constructs. The mouse is the only mammal that provides such a rich resource of genetic diversity coupled with the potential for extensive genome manipulation, and is therefore a powerful application for modeling human disease. This poster review outlines the major genome manipulations available in the mouse that are used to understand human disease: natural variation, reverse genetics, forward genetics, transgenics and transposons. Each of these applications will be essential for understanding the diversity that is being discovered within the human population. © 2011. Published by The Company of Biologists Ltd.
Siedel H.,TU Dresden
Quarterly Journal of Engineering Geology and Hydrogeology | Year: 2013
Building stones utilized on façades in the city centres of the three largest cities in the Free State of Saxony (Germany), Dresden, Leipzig, and Chemnitz, were recorded for a comparative study and related to the age of the buildings and to their use for distinct building elements. The cities show different patterns of stone utilization according to their geological background and historical development. Local building stones quarried nearby dominate until the middle of the 19th century, when the development of industries and infrastructure started to facilitate the delivery of a greater number of stone varieties from further afield. The use of natural stone for certain construction elements on buildings has been controlled not only by functional aspects and appropriate technical properties but also by fashion, the economic background, and political restrictions. Additional recording of the weathering state of different types of building stones after long-term exposure allows a comparative assessment, thus giving useful hints on their long-term behaviour and durability.
Rudolph W.W.,TU Dresden |
Irmer G.,TU Bergakademie Freiberg
Dalton Transactions | Year: 2013
Raman spectra of aqueous calcium salt solutions, Ca(ClO4) 2, CaCl2, CaBr2, and Ca(NO3) 2, were measured from the concentrated solution stage to more dilute solutions (6.08-0.1 mol L-1) at 23 °C in water and heavy water down to 40 cm-1. In aqueous Ca(ClO4)2 solutions a strongly polarized band at 283 cm-1 (full width at half height (fwhh) = 68 cm-1) was observed. The mode at 283 cm-1 was assigned to the Ca-O symmetric stretching vibration of the hexa-aqua Ca 2+ ion, [Ca(OH2)6]2+, and the integrated band intensity showed a linear dependency with Ca(ClO 4)2 concentration. In a Ca(ClO4)2 solution of heavy water a similar band was observed at 268 cm-1 (fwhh = 64 cm-1) of the deuterated species, [Ca(OD2) 6]2+. In the OH stretching region of water a band of weakly H-bonded O-H oscillators was detected at 3550 cm-1 due to O-H⋯ClO4-. In D2O solutions a similar band was found at 2590 cm-1 due to O-D⋯ClO4 -. The band at 283 cm-1, in addition to the restricted translation mode of water at ∼180 cm-1, was also observed in dilute to moderately concentrated CaCl2 and CaBr2 solutions. This fact is strong evidence that neither Cl- nor Br - penetrate the first hydration sphere of Ca2+ in solution with mol ratio H2O:CaCl2/CaBr2 ≥ 18:1 and the coordination number is unchanged. Furthermore, the influence of CaCl 2 on the water bands of the librational band region (300-900 cm -1), the deformation band of water and the O-H stretching region has been described. In a hydrate melt and very concentrated solutions of CaCl 2 with a mol ratio H2O:CaCl2 ≤ 9:1, however, contact ion pairs between Ca2+ and Cl- are formed and the 283 cm-1 band vanishes. Preliminary DFT calculations on the contact ion pair, [Ca(OH2)5Cl]+, confirm its existence in such hydrate melts. In aqueous solutions of Ca(NO3)2, NO3- penetrates the first hydration sphere and spectroscopic evidence of weak nitrato-complex formation could be detected. This is the first comprehensive report on the symmetric stretching vibration of the hydrated Ca2+ ion, [Ca(OH2)6]2+, in aqueous solution. DFT calculations concerning geometry optimizations and frequency calculations at the B3LYP/6-311+G(d,p) level on the hexa-aqua Ca 2+ ion in the gas phase and including a solvation-sphere were performed. The calculations on [Ca(OH2)6]2+ and [Ca(OD2)6]2+ with a solvation-sphere allowed the determination of the six CaO6 skeletal modes and supported the assignment of the symmetric stretching mode, ν1CaO6 of [Ca(OH2)6]2+ and [Ca(OD2) 6]2+. Discrete cluster calculations on a cluster with six inner sphere and twelve outer sphere water molecules, [Ca(OH2) 6(OH2)12]2+ at the same level of theory, led to a Ca-O internuclear distance at 2.383 Å and 4.475 Å for the inner sphere and the outer sphere respectively. This journal is © 2013 The Royal Society of Chemistry.
Schellong S.M.,TU Dresden
Hamostaseologie | Year: 2013
Deep vein thrombosis is a chronic disease with a continuing risk of recurrence. In a patient with recurrence long term prognosis and treatment are significantly altered both carrying their own risks not only in the acute phase but mainly in the long term perspective. Thus, accurate diagnosis of recurrence is of utmost importance for the fate of the patient. Diagnosis of a first DVT episode is well established and follows an algorithm including clinical prediction rules, D-Dimer testing and compression ultrasound. Due to the previous episode the efficiency of all three elements is impaired in a patient with suspected recurrence. This opens up areas of uncertainty which have to be filled by individual clinical judgement. Guidelines reflect this difficulty by providing mainly weak recommendations based on sparse data. The present review summarizes what is known about the performance of tools for DVT diagnosis, discusses recent guidelines, and finally gives personally weighed recommendations how to deal with this peculiar diagnostic situation. In conclusion, it will turn out that the well accepted diagnostic algorithm for a first DVT may be applied as well if the lower efficiency is regarded. Compression ultrasound largely benefits from a baseline assessment at the end of the previous episode. The order of tests may be discussed according to local and regional attitudes. © Schattauer 2013.
Hajishengallis G.,University of Pennsylvania |
Chavakis T.,TU Dresden
Trends in Immunology | Year: 2013
Leukocyte recruitment is a central immune process. Multiple factors have been described to promote leukocyte infiltration into inflamed tissues, but only recently has evidence for endogenous negative modulators of this inflammatory process emerged. The discovery of several locally produced modulators has emerged into a new field of endogenous inhibitors of leukocyte extravasation. Recent findings from several inflammatory disease models show that tissues can self-regulate the recruitment of inflammatory cells, suggesting that local tissues may have a greater 'regulatory say' over the immune response than previously appreciated. Here, we propose that locally produced modulators of leukocyte recruitment may represent local homeostatic mechanisms that tissues and organs may have evolved for protection against the destructive potential of the immune system. © 2012 Elsevier Ltd.
Leyh C.,TU Dresden
Advances in Enterprise Information Systems II - Proceedings of the 5th International Conference on Research and Practical Issues of Enterprise Information Systems, CONFENIS 2011 | Year: 2012
The aim of our study was to gain insight into the research field of critical success factors (CSF) of enterprise resource planning (ERP) implementation projects. Therefore, we conducted a literature review, more specifically a systematic review of relevant articles in five different databases and among several international conference proceedings. Ultimately, we identified 185 relevant papers (95 single or multiple case studies, 55 surveys, and 35 literature reviews or articles from which CSFs can be derived). From these existing studies, we discovered 31 different CSFs for ERP implementation. The top three factors identified are Top management support and involvement, Project management, and User training. However, most of the relevant papers focus on large enterprises. Only 12 papers explicitly focus on smaller and medium-sized enterprises (S&MEs), which is clearly a research gap in this field. © 2012 Taylor & Francis Group, London.
Petzold C.,TU Dresden
The review of diabetic studies : RDS | Year: 2010
Studies employing T cell receptor transgenic T cells have convincingly shown that selective delivery of non-self model antigens to DEC-205(+) dendritic cells (DCs) in the steady-state can induce Foxp3-expressing CD4(+)CD25(+) regulatory T (Treg) cells from conventional CD4(+)CD25(-)Foxp3(-) T cells. Although of considerable clinical interest, the concept of DC-targeted de novo generation of antigen-specific Treg cells has not yet been evaluated for self-antigens and self-reactive CD4(+) T cells in the non-obese diabetic (NOD) mouse model of type 1 diabetes (T1D). Here, we show in proof-of-principle experiments that targeting a mimotope peptide to the endocytic receptor DEC-205 on DCs in NOD mice induces efficient conversion of pancreatic beta-cell-reactive BDC2.5 CD4(+) T cells into long-lived Foxp3(+) Treg cells. Of note, conversion efficiency in normoglycemic and hyperglycemic mice with early diabetes onset was indistinguishable. While de novo generation of BDC2.5 Treg cells did not interfere with disease progression, anti-DEC-205-mediated targeting of whole proinsulin in prediabetic NOD mice substantially reduced the incidence of diabetes. These results suggest that promoting antigen-specific Treg cells in vivo might be a feasible approach towards cellular therapy in T1D.
Van Pee K.-H.,TU Dresden
Methods in Enzymology | Year: 2012
Our knowledge about the enzymes catalyzing the incorporation of halide ions during the biosynthesis of halometabolites has increased tremendously during the last 15 years. Between 1960 and 1995, haloperoxidases were the only halogenating enzymes known. However, absolute proof for the connection of haloperoxidases to the biosynthesis of halometabolites is still missing. In 1997, FADH2-dependent halogenases were identified as the type of halogenating enzymes responsible for the incorporation of chloride and bromide atoms into aromatic and aliphatic compounds activated for electrophilic attack. FADH2-dependent halogenases are two-component systems consisting of a flavin reductase providing the FADH2 required by the halogenase. Elucidation of the three-dimensional structure of FADH2-dependent halogenases led to the understanding of the reaction mechanism, which involves the formation of hypohalous acids. Unactivated carbon atoms were found to be halogenated by nonheme iron, α-ketoglutarate- and O2-dependent halogenases. The reaction mechanism of this type of halogenase was shown to involve the formation of a substrate radical. These two types of halogenating enzymes, together with the much less common fluorinases, are the major types of halogenating enzymes. However, the existence of other types of halogenating enzymes, yet not detected, cannot be completely ruled out. Here, we describe the detection, purification, characterization, and reaction mechanisms of flavin-dependent halogenases and of nonheme iron, α-ketoglutarate- and O2-dependent halogenases. © 2012 Elsevier Inc.
van Pee K.-H.,TU Dresden
Alkaloids: Chemistry and Biology | Year: 2012
Our understanding of the biosynthetic pathways of halogenated alkaloids has made enormous progress during the last decade. Earlier investigations into the biosynthesis of secondary metabolites in general mostly relied on feeding studies using labeled precursors and analysis of their incorporation into the final products or on the use of mutating agents. The cloning of genes coding for enzymes known or assumed to be involved in the biosynthesis of halogenated alkaloids allowed the isolation of the biosynthetic gene clusters of a number of halogenated alkaloids. Knowledge gathered about the halogenating enzymes assumed to be involved in the incorporation of halogen atoms during alkaloid biosynthesis was of considerable importance for the identification of such gene clusters. The genes of halogenases requireing the reduced form of flavin adenine dinucleotide (FADH2-dependent halogenases) known to catalyze the incorporation of halogen atoms into electron-rich substrates such as pyrrole carboxylic acid derivatives derived from proline- or tryptophan-derived alkaloids have been used to isolate gene clusters of halogenated alkaloids. There are also examples, where the genes of nonheme iron, α-ketoglutarate- and O2-dependent halogenases that catalyze the halogenation of nonactivated carbon atoms, have been used to detect biosynthetic gene clusters. Biosynthesis of halogenated alkaloids can proceed via nonribosomal peptide biosynthesis as well as via polyketide biosynthesis or a mixture of both. Characterization of gene clusters and annotation of predicted enzymes allowed the proposal of individual steps in the pathways. Incorporation of the halogen atoms was found to occur as the first step as in the case of tryptophan-derived alkaloids or at a later step in the biosynthetic pathway. © 2012 Elsevier Inc.
Valtink M.,TU Dresden
Investigative ophthalmology & visual science | Year: 2012
Recently, insertion of immuno-modulatory or anti-apoptotic genes into corneal endothelial cells (HCECs) came into focus. Basic FGF-2 occurs in one secreted (low molecular weight, LMW, 18 kD) and four nuclear (high molecular weight, HMW, 22-34 kD) isoforms. HMW isoforms are known differentiation and survival factors, while LMW FGF-2 is a known mitogen. The effect of FGF-2 overexpression of each of the five known isoforms on HCEC cell survival after lentiviral gene transfer in different culture media was investigated. Cells were transduced with lentiviral vectors encoding for each of the five FGF-2 isoforms. Transduction efficiency and expression of individual FGF-2 isoforms was assessed by marker gene transfer and western blotting. Primary HCECs were cultured and transduced in four different media previously described for HCEC cultivation or corneal organ cultivation. Cytotoxic effect of virus infection and a possible rescue effect of FGF-2 overexpression were determined by resazurin conversion assay. Transduction with FGF-2 encoding lentiviral vectors resulted in overexpression of the respective isoform in all tested cell populations. Western blotting after total cell lysis proved nuclear localization of transgenic HMW isoforms. Overexpression of HMW FGF-2-especially 34 kD FGF-2-reduced lentiviral cytotoxicity, while overexpression of LMW FGF-2 aggravated viral cytotoxicity. Cytotoxicity of lentiviral gene transfer in corneal endothelial cells may be reduced by using bicistronic vectors that encode for the target gene and the 34-kD isoform of human FGF-2. Such cotransduction of a survival factor may increase cell survival after gene transfer, thereby improving gene therapeutic approaches.
Birk C.,TU Dresden |
Prempramote S.,University of New South Wales |
Song C.,University of New South Wales
International Journal for Numerical Methods in Engineering | Year: 2012
A high-order local transmitting boundary to model the propagation of acoustic or elastic, scalar or vector-valued waves in unbounded domains of arbitrary geometry is proposed. It is based on an improved continued-fraction solution of the dynamic stiffness matrix of an unbounded medium. The coefficient matrices of the continued-fraction expansion are determined recursively from the scaled boundary finite element equation in dynamic stiffness. They are normalised using a matrix-valued scaling factor, which is chosen such that the robustness of the numerical procedure is improved. The resulting continued-fraction solution is suitable for systems with many DOFs. It converges over the whole frequency range with increasing order of expansion and leads to numerically more robust formulations in the frequency domain and time domain for arbitrarily high orders of approximation and large-scale systems. Introducing auxiliary variables, the continued-fraction solution is expressed as a system of linear equations in iω in the frequency domain. In the time domain, this corresponds to an equation of motion with symmetric, banded and frequency-independent coefficient matrices. It can be coupled seamlessly with finite elements. Standard procedures in structural dynamics are directly applicable in the frequency and time domains. Analytical and numerical examples demonstrate the superiority of the proposed method to an existing approach and its suitability for time-domain simulations of large-scale systems. © 2011 John Wiley & Sons, Ltd.
Hanefeld M.,TU Dresden |
Duetting E.,Novartis |
Bramlage P.,Institute For Pharmakologie Und Praventive Medizin
Cardiovascular Diabetology | Year: 2013
Background: Hypoglycaemia has been associated with increased cardiovascular (CV) risk and mortality in a number of recent multicentre trials, but the mechanistic links driving this association remain ill defined. This review aims to summarize the available data on how hypoglycaemia may affect CV risk in patients with diabetes.Methods: This was a systematic review of available mechanistic and clinical studies on the relationship between hypoglycaemia and cardiovascular risk. Study outcomes were compiled from relevant articles, and factors contributing to hypoglycaemia-mediated CVD and its complications are discussed.Results: Six recent comprehensive clinical trials have reinforced the critical importance of understanding the link between hypoglycaemia and the CV system. In addition, 88 studies have indicated that hypoglycaemia mechanistically contributes to CV risk by increasing thrombotic tendency, causing abnormal cardiac repolarization, inducing inflammation, and contributing to the development of atherosclerosis. These hypoglycaemia-associated risk factors are conducive to events such as unstable angina, non-fatal and fatal myocardial infarction, sudden death, and stroke in patients with diabetes.Conclusions: Emerging data suggest that there is an impact of hypoglycaemia on CV function and mechanistic link is multifactorial. Further research will be needed to ascertain the full impact of hypoglycaemia on the CV system and its complications. © 2013 Hanefeld et al.; licensee BioMed Central Ltd.
Waurick M.,TU Dresden
Mathematical Methods in the Applied Sciences | Year: 2012
We present an abstract approach to homogenization in a Hilbert space setting. Related compactness results are obtained. Moreover, the homogenized equations may be computed explicitly, if periodicity is imposed. Examples for the applicability of our homogenization result for linear ordinary (integro-)differential equations are given. Copyright © 2012 John Wiley & Sons, Ltd.
Guenther M.,TU Dresden
Europace : European pacing, arrhythmias, and cardiac electrophysiology : journal of the working groups on cardiac pacing, arrhythmias, and cardiac cellular electrophysiology of the European Society of Cardiology | Year: 2013
Device implantation may be challenging in patients with venous abnormalities. The most common congenital variation--frequently associated with other congenital abnormalities--is described as persistent left superior vena cava (PLSVC). The present case series demonstrates successful implantable cardioverter defibrillator (ICD) lead implantation in the most common anatomic variations of PLSVC. All types of current ICD models (single and dual chamber, VDD, and cardiac resynchronization therapy devices) were used. Angiographic findings and implantation techniques (e.g. guiding and diagnostic catheters, wires, occlusion balloons, and rotation sequences) are presented in images and movie sequences. Device implantation in patients with PLSVC may be complex but a successful transvenous approach is possible in most of the cases. Careful imaging prior to implantation procedure is essential for understanding the individual anatomy and in order to choose adequate material and implantation strategy.
Ganesh R.,Leibniz Institute for Solid State and Materials Research |
Van Den Brink J.,Leibniz Institute for Solid State and Materials Research |
Van Den Brink J.,TU Dresden |
Nishimoto S.,Leibniz Institute for Solid State and Materials Research
Physical Review Letters | Year: 2013
Using the density matrix renormalization group, we determine the phase diagram of the spin-1/2 Heisenberg antiferromagnet on a honeycomb lattice with a nearest-neighbor interaction J1 and a frustrating, next-nearest-neighbor exchange J2. As frustration increases, the ground state exhibits Néel, plaquette, and dimer orders, with critical points at J2/J1=0.22 and 0.35. We observe that both the spin gap and the corresponding order parameters vanish continuously at both the critical points, indicating the presence of deconfined quantum criticality. © 2013 American Physical Society.
Borrell V.,and oUniversidad Miguel Hernandez |
Calegari F.,TU Dresden
Neuroscience Research | Year: 2014
In the last few years, several studies have revisited long-held assumptions in the field of brain development and evolution providing us with a fundamentally new vision on the mechanisms controlling its size and shape, hence function. Among these studies, some described hitherto unforeseeable subtypes of neural progenitors while others reinterpreted long-known observations about their cell cycle in alternative new ways. Most remarkably, this knowledge combined has allowed the generation of mammalian model organisms in which brain size and folding has been selectively increased giving us the means to understand the mechanisms underlying the evolution of the most complex and sophisticated organ. Here we review the key findings made in this area and make a few conjectures about their evolutionary meaning including the likelihood of Martians conquering our planet. © 2014 The Authors.
Plieth W.,TU Dresden
Journal of Solid State Electrochemistry | Year: 2011
The relation between layer properties and structure of the deposit is of permanent importance in the development of electrocrystallization. The continuous question is the influence of the experimental conditions on the structure and with this bridge on the properties of electrodeposits. A very important step in electrodeposition is nucleation. Some recent developments of nucleation will be discussed. An important factor to influence nucleation and growths are additives. Adsorption of additives is still described by the thermodynamic approach of adsorption isotherms. But a new impetus might provide the transfer of Pearson"s hard-soft concept to adsorption on electrified interfaces. An important step is the correlation of hardness and softness with the chemical potential of electrons and the dependence of the chemical potential on the electrode potential. A further new step is the application of distributed field calculations to calculate chemical potentials of electrons. An outlook into further developments is given at the end of the article. © 2011 Springer-Verlag.
Fehske A.,TU Dresden |
Fettweis G.,IBM |
Malmodin J.,RBS Basic Technology Research Unit |
Biczok G.,Norwegian University of Science and Technology
IEEE Communications Magazine | Year: 2011
This article quantifies the global carbon footprint of mobile communication systems, and discusses its ecological and economic implications. Using up-to-date data and life cycle assessment models, we predict an increase of CO2 equivalent emissions by a factor of three until 2020 compared to 2007, rising from about 86 to 235 Mto CO2e, suggesting a steeper increase than predicted in the well-known SMART2020 report. We provide a breakdown of the global carbon footprint, which reveals that production of mobile devices and global radio access network operation will remain the major contributors, accompanied by an increasing share of emissions due to data transfer in the backbone resulting from rising mobile traffic volumes. The energy bill due to network operation will gain increasing importance in cellular business models. Furthermore, technologies to reduce energy consumption are considered a key enabler for the spread of mobile communications in developing countries. Taking into account several scenarios of technological advancement and rollout, we analyze the overall energy consumption of global radio access networks and illustrate the saving potential of green communication technologies. We conclude that, conditioned on quick implementation and alongside other "classical" improvements of spectral efficiency, these technologies offer the potential to serve three orders of magnitude more traffic with the same overall energy consumption as today. © 2011 IEEE.
Vojta M.,TU Dresden
Physical Review Letters | Year: 2013
For coupled-dimer magnets with quenched disorder, we introduce a generalization of the bond-operator method, appropriate to describe both singlet and magnetically ordered phases. This allows for a numerical calculation of the magnetic excitations at all energies across the phase diagram, including the strongly inhomogeneous Griffiths regime near quantum criticality. We apply the method to the bilayer Heisenberg model with bond randomness and characterize both the broadening of excitations and the transfer of spectral weight induced by disorder. Inside the antiferromagnetic phase this model features the remarkable combination of sharp magnetic Bragg peaks and broad magnons, the latter arising from the tendency to localization of low-energy excitations. © 2013 American Physical Society.
Bley T.,TU Dresden
Advances in Biochemical Engineering/Biotechnology | Year: 2011
The development of dynamic modelling of microbial populations in bioprocesses is reviewed. In the 1960s Arnold Fredrickson established the theoretical basis of such models, and other researchers have subsequently advanced them. This review explores the relationships that describe cell proliferation and evaluates the importance of the application of flow cytometry to the fundamental parameterisation of the models for their use in bioprocess engineering. The section "Individual-Based Modelling" discusses recent theoretical developments. Delaydifferential equations are demonstrated to describe accurately temporal variation of the cell proliferation cycle and specialised approaches and related iconography are applied to stochastic and deterministic modelling of stages of cellular development. Synchronised cultures of the bacterium Cupriavidus necator were prepared and monitored using a flow cytometer. The data obtained demonstrate that cell proliferation could be simulated quantitatively using the developed model. © Springer-Verlag Berlin Heidelberg 2010.
Barnhofer T.,University of Oxford |
Chittka T.,TU Dresden
Behaviour Research and Therapy | Year: 2010
Although neuroticism has long been established as an important risk factor for depression, the mechanisms through which this temperamental predisposition translates into the occurrence of symptoms are still relatively unclear. This study investigated cognitive reactivity, i.e. the ease with which particular patterns of negative thinking are reactivated in response to mild low mood, as a potential mediator. Individuals with (N = 98) and without a previous history of depression (N = 83) who had provided neuroticism scores six years previously were assessed for cognitive reactivity and current symptoms of depression using self-report questionnaires. Tendencies to respond to mild low mood with ruminative thinking mediated the relation between neuroticism and current symptoms of depression in both groups. Reactivation of hopelessness and suicidal thinking occurred as an additional mediator only in those with a history of previous depression. The results suggest that neuroticism predisposes individuals to depression by generally increasing the likelihood of ruminative responses to low mood. In those with a history of depression in the past, neuroticism additionally increases risk of recurrence by facilitating reactivation of previously associated patterns such as suicidal thinking and hopelessness. These findings suggest potential targets for interventions to help preventing the occurrence, or recurrence of depression in those who due to their temperamental predisposition are at an increased risk. © 2009 Elsevier Ltd.
Blauert J.,Ruhr University Bochum |
Jekosch U.,TU Dresden
AES: Journal of the Audio Engineering Society | Year: 2012
Sound quality is a complex and multilayered phenomenon. When analyzing or modeling the formation process of sound-quality judgments, a variety of quality elements and quality featureshave to be taken into account, whereby the actual relevance and salience of each of them is situation dependent. In the following we present some ideas with the aim of structuring the quality-formation process into different layers according to the amount of abstraction involved. Depending on the amount of abstraction, different sets of references and evaluation and assessment methods have to be employed.
Chung C.-H.,National Cheng Kung University |
Robens T.,TU Dresden
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013
In this work, we present the extension of an alternative subtraction scheme for next-to-leading order QCD calculations to the case of an arbitrary number of massless final state partons. The scheme is based on the splitting kernels of an improved parton shower and comes with a reduced number of final state momentum mappings. While a previous publication including the setup of the scheme has been restricted to cases with maximally two massless partons in the final state, we here provide the final state real emission and integrated subtraction terms for processes with any number of massless partons. We apply our scheme to three jet production at lepton colliders at next-to-leading order and present results for the differential C parameter distribution. © 2013 American Physical Society.
Braun R.,TU Dresden
Communications in Computer and Information Science | Year: 2015
The Business Process Model and Notation (BPMN) is the prevalent conceptual modeling language for business process modeling and process analysis. BPMN benefits from its expressiveness and the well-defined meta model, which is defined by the Meta Object Facility (MOF). The emergence of BPMN entails an increasing demand for language extensions in order to both benefit from the dissemination and apposite concepts. Although BPMN is one of very few languages that explicitly provides capabilities for its extension, the proposed mechanism reveals some shortcomings and inaccuracies concerning model abstractions, specificity and semantical clarity. A list of improvable aspects is hence provided based on an in-depth analysis of the extension mechanism. The analysis has a special focus on the abstract syntax (BPMN meta model). Several techniques for enhanced BPMN extension design are proclaimed by adapting alternative mechanisms for language extensibility: Profiling, under specification (hooking) and annotation (plugins and add-ons). The stated mechanisms are partly adapted from other modeling languages (profiling) or the field of Software Engineering (hooking, plug-ins, add-ons). Each approach is described by its core concepts, its application and by some examples. The approaches are finally compared regarding several criteria. © Springer International Publishing Switzerland 2015.
Soetaert K.,Netherlands Institute of Ecology |
Petzoldt T.,TU Dresden |
Setzer R.W.,U.S. Environmental Protection Agency
Journal of Statistical Software | Year: 2010
In this paper we present the R package deSolve to solve initial value problems (IVP) written as ordinary differential equations (ODE), differential algebraic equations (DAE) of index 0 or 1 and partial differential equations (PDE), the latter solved using the method of lines approach. The differential equations can be represented in R code or as compiled code. In the latter case, R is used as a tool to trigger the integration and post-process the results, which facilitates model development and application, whilst the compiled code significantly increases simulation speed. The methods implemented are efficient, robust, and well documented public-domain Fortran routines. They include four integrators from the ODEPACK package (LSODE, LSODES, LSODA, LSODAR), DVODE and DASPK2.0. In addition, a suite of Runge-Kutta integrators and special-purpose solvers to efficiently integrate 1-, 2-and 3-dimensional partial differential equations are available. The routines solve both stiff and non-stiff systems, and include many options, e.g., to deal in an efficient way with the sparsity of the Jacobian matrix, or finding the root of equations. In this article, our objectives are threefold: (1) to demonstrate the potential of using R for dynamic modeling, (2) to highlight typical uses of the different methods implemented and (3) to compare the performance of models specified in R code and in compiled code for a number of test cases. These comparisons demonstrate that, if the use of loops is avoided, R code can efficiently integrate problems comprising several thousands of state variables. Nevertheless, the same problem may be solved from 2 to more than 50 times faster by using compiled code compared to an implementation using only R code. Still, amongst the benefits of R are a more flexible and interactive implementation, better readability of the code, and access to R's high-level procedures. deSolve is the successor of package odesolve which will be deprecated in the future; it is free software and distributed under the GNU General Public License, as part of the R software project.
Altinsoy M.E.,TU Dresden
AES: Journal of the Audio Engineering Society | Year: 2012
In our daily lives, we usually perceive an event via more than one sensory modality (e.g., vision, hearing, touch). Therefore, multimodal integration and interactions play an important role when we use objects and for event recognition in our environment. A virtual environment (VE) is a computer simulation of a realistic-looking and interactive world. VEs should take into account the multisensory nature of humans and communicate with the user not only through vision but also through other modalities. In addition to vision, hearing and touch are the most commonly used communication channels. Recently, a variety of products with additional tactile input and output capabilities have been developed (e.g., Apple iPhone and other touch-screen devices, NintendoWii, etc.). Some of these devices provide new possibilities for interacting with a computer, including the auditory modality. Binaural synthesis and rendering are becoming key technologies for multimedia products. Virtual environments are no longer limited to academic research; they have commercial applications, particularly in medicine, game, and entertainment industries. Thus, the quality of VEs is becoming increasingly important. User interaction with a VE is a key issue in the perception of its quality. Several studies have discussed the quality of displays, input and output devices (for different modalities) as well as software and hardware issues; however, multimodal user interaction should also be examined. This paper focuses on the parameters that influence the quality of audio-tactile VEs.
Franke K.,TU Dresden
Blood | Year: 2013
Organisms living under aerobic conditions need oxygen for the metabolic conversion of nutrition into energy. With the appearance of increasingly complex animals, a specialized transport system (erythrocytes) arose during evolution to provide oxygen to virtually every single cell in the body. Moreover, in case of low environmental partial pressure of oxygen, the number of erythrocytes automatically increases to preserve sustained oxygen delivery. This process relies predominantly on the cytokine erythropoietin (Epo) and its transcription factor hypoxia inducible factor (HIF), whereas the von Hippel-Lindau (VHL) ubiquitin ligase as well as the oxygen-sensitive prolyl hydroxylases (PHDs) represent essential regulators of this oxygen-sensing system. Deregulation of particular members of this pathway (eg, PHD2, HIF2α, VHL) lead to disorders in blood homeostasis as a result of insufficient (anemia) or excessive (erythrocytosis) red blood cell production.
Bschor T.,Schlosspark Clinic |
Bschor T.,TU Dresden
Drugs | Year: 2014
Recent high-quality studies have confirmed the central role of lithium in the treatment of bipolar disorder and have established lithium as the drug of first choice for long-term prophylaxis in this condition. However, several indications for its use in unipolar major depression are also based on sound evidence. This includes lithium augmentation as a main strategy for depressed patients not responding to an antidepressant, lithium prophylaxis for recurrent unipolar depression as an alternative to prophylaxis with an antidepressant, and lithium's unique anti-suicidal properties. Lithium monotherapy, on the other hand, is not established for acute treatment of depression. Lithium therapy should be a core competency of every psychiatrist, enabling the safe use of lithium, to the benefit of our patients. © 2014 Springer International Publishing Switzerland.
Aringer M.,TU Dresden
Arthritis Research and Therapy | Year: 2012
Only after biological response modifiers have become available have we begun to understand some of the complex functions of TNF in the human immune system. TNF is clearly essential for fighting intracellular pathogens, but probably not essential for fighting tumors. TNF influence on the humoral immune response, in contrast, has been more complicated to decipher, since TNF blockade is associated with both autoantibody formation and (somewhat) reduced responses to vaccination. Novel data now show that TNF is good for the humoral immune response. Vaccinations still work, however, and should be strongly recommended. © 2012 BioMed Central Ltd.
Narciss S.,TU Dresden
Digital Education Review | Year: 2013
This paper describes the interactive tutoring feedback model (ITF-model; Narciss, 2006; 2008), and how it can be applied to the design and evaluation of feedback strategies for digital learning environments. The ITF-model conceptualizes formative tutoring feedback as a multidimensional instructional activity that aims at contributing to the regulation of a learning process in order to help learners acquire or improve the competencies needed to master learning tasks. It integrates findings from systems theory with recommendations of prior research on interactive instruction and elaborated feedback, on task analyses, on error analyses, and on tutoring techniques. Based on this multi-dimensional view of formative tutoring feedback methodological implications for designing and investigating multiple effects of feedback under multiple individual and situational conditions are described. Furthermore, the paper outlines how the implications of the ITF-model have been applied in several studies to the design and evaluation of tutoring feedback strategies for digital learning environments (e.g., Narciss, 2004; Narciss & Huth, 2006; Narciss, Schnaubert, Andres, Eichelmann, Goguadze, & Sosnovsky, 2013).
Baader F.,TU Dresden |
Pealoza R.,University of Leipzig
Journal of Logic and Computation | Year: 2010
Axiom pinpointing has been introduced in description logics (DLs) to help the user to understand the reasons why consequences hold and to remove unwanted consequences by computing minimal (maximal) subsets of the knowledge base that have (do not have) the consequence in question. Most of the pinpointing algorithms described in the DLliterature are obtained as extensions of the standard tableau-based reasoning algorithms for computing consequences from DL knowledge bases. Although these extensions are based on similar ideas, they are all introduced for a particular tableau-based algorithm for a particular DL. The purpose of this article is to develop a general approach for extending a tableau-based algorithm to a pinpointing algorithm. This approach is based on a general definition of 'tableau algorithms,' which captures many of the known tableau-based algorithms employed in DLs, but also other kinds of reasoning procedures.
DiFiore B.,University of Cambridge |
Davey N.,University of California at San Francisco |
Davey N.,Structural and Computational Biology Unit |
Hagting A.,University of Cambridge |
And 4 more authors.
Developmental Cell | Year: 2015
The anaphase-promoting complex or cyclosome (APC/C) is the ubiquitin ligase that regulates mitosis by targeting specific proteins for degradation at specific times under the control of the spindle assembly checkpoint (SAC). How the APC/C recognizes its different substrates is a key problem in the control of cell division. Here, we have identified the ABBA motif in cyclin A, BUBR1, BUB1, and Acm1, and we show that it binds to the APC/C coactivator CDC20. The ABBA motif in cyclin A is required for its proper degradation in prometaphase through competing with BUBR1 for the same site on CDC20. Moreover, the ABBA motifs in BUBR1 and BUB1 are necessary for the SAC to work at full strength and to recruit CDC20 to kinetochores. Thus, we have identified a conserved motif integral to the proper control of mitosis that connects APC/C substrate recognition with the SAC. © 2015 Elsevier Inc.
Skokos C.,Max Planck Institute for the Physics of Complex Systems |
Gerlach E.,TU Dresden
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2010
We present and compare different numerical schemes for the integration of the variational equations of autonomous Hamiltonian systems whose kinetic energy is quadratic in the generalized momenta and whose potential is a function of the generalized positions. We apply these techniques to Hamiltonian systems of various degrees of freedom and investigate their efficiency in accurately reproducing well-known properties of chaos indicators such as the Lyapunov characteristic exponents and the generalized alignment indices. We find that the best numerical performance is exhibited by the "tangent map method," a scheme based on symplectic integration techniques which proves to be optimal in speed and accuracy. According to this method, a symplectic integrator is used to approximate the solution of the Hamilton equations of motion by the repeated action of a symplectic map S, while the corresponding tangent map TS is used for the integration of the variational equations. A simple and systematic technique to construct TS is also presented. © 2010 The American Physical Society.
Wollina U.,TU Dresden
Clinics in Dermatology | Year: 2011
Rosacea is a chronic inflammatory disease with a predominance of facial manifestations. The prevalence is increasing with age, peaking in the group aged older than 65 years. In 1997, one in eight Americans was aged 65 years and older. By 2030, more than 70 million individuals will be in this age group. This contribution reviews the current understanding of pathogenesis, aggravating factors, classification, comorbidities, and treatment options. Rosacea is a manageable disease that negatively affects quality of life. Rosacea increases the risk of depression and shows a significant proportion of extracutaneous manifestations, in particular ocular rosacea. © 2011 Elsevier Inc.
Zuber K.,TU Dresden
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2012
The potential real-time spectroscopy of solar pp-neutrinos using 150Nd as target is investigated. The threshold of 196 keV would be the lowest of all solar neutrino experiments running so far. Experimental rates and parameters are discussed, about 906 SNU can be expected from pp-neutrinos and another 574 SNU from 7Be. Furthermore, it is investigated whether charged current reactions might cause a new background component for future double beta decay experiments based on a large amount of 150Nd. © 2012.
Al-Diban S.,TU Dresden |
Ifenthaler D.,Albert Ludwigs University of Freiburg
Educational Technology and Society | Year: 2011
Mental models are basic cognitive constructs that are central for understanding phenomena of the world and predicting future events. Our comparison of two analysis approaches, SMD and QFCA, for measuring externalized mental models reveals different levels of abstraction and different perspectives. The advantages of the SMD include possibilities for statistical testing of single criteria and big groups. Its disadvantages include a comparatively low pedagogical expressiveness of the more formal criteria. An analysis of single cases with the help of QFCA avoids imprecision by virtue of many steps of analysis and seems more significant on a qualitative level. The main limitation of QFCA is that comparisons are possible for small groups or knowledge sections only. The content-based results open various possibilities for comparing mental-model representations by single cases or groups with different pedagogical implications. © International Forum of Educational Technology & Society (IFETS).
Mudriievskyi S.,TU Dresden
AEU - International Journal of Electronics and Communications | Year: 2014
Power Line Communications (PLC) is currently well-known technology. In the last 10-15 years its development and improvements became considerable so that the mass deployment takes place. In this paper we describe the main trends of PLC development. © 2014 Elsevier GmbH.
Goudelis A.,German Electron Synchrotron |
Lebedev O.,German Electron Synchrotron |
Park J.-H.,TU Dresden
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2012
Due to the smallness of the lepton Yukawa couplings, higher dimensional operators can give a significant contribution to the lepton masses. In this case, the lepton mass matrix and the matrix of lepton-Higgs couplings are misaligned leading to lepton flavor violation (LFV) mediated by the Standard Model Higgs boson. We derive model-independent bounds on the Higgs flavor violating couplings and quantify LFV in decays of leptons and electric dipole moments for a class of lepton-Higgs operators contributing to lepton masses. We find significant Higgs-mediated LFV effects at both 1-loop and 2-loop levels. © 2011 Elsevier B.V.
Lienig J.,TU Dresden
Proceedings of the International Symposium on Physical Design | Year: 2013
Electromigration (EM) is one of the key concerns going forward for interconnect reliability in integrated circuit (IC) design. Although analog designers have been aware of the EM problem for some time, digital circuits are also being affected now. This talk addresses basic design issues and their effects on electromigration during interconnect physical design. The intention is to increase current density limits in the interconnect by adopting electromigration-inhibiting measures, such as short-length and reservoir effects. Exploitation of these effects at the layout stage can provide partial relief of EM concerns in IC design flows in future. Copyright © 2013 ACM.
Birk C.,TU Dresden |
Song C.,University of New South Wales
Computational Mechanics | Year: 2010
A procedure to construct temporally local schemes for the computation of fractional derivatives is proposed. The frequency-domain counterpart (iω) α of the fractional differential operator of order α is expressed as an improper integral of a rational function in iω. After applying a quadrature rule, the improper integral is approximated by a series of partial fractions. Each term of the partial fractions corresponds to an exponential kernel in the time domain. The convolution integral in a fractional derivative can be evaluated recursively leading to a local scheme. As the arguments of the exponential functions are always real and negative, the scheme is stable. The present procedure provides a convenient way to evaluate the quality of a given algorithm by examining its accuracy in fitting the function (iω) α. It is revealed that the non-classical solution methods for fractional differential equations proposed by Yuan and Agrawal (ASME J Vib Acoust 124:321-324, 2002) and by Diethelm (Numer Algorithms 47:361-390, 2008) can also be interpreted as applying specific quadrature rules to evaluate the improper integral numerically. Over a wider range of frequencies, Diethelm's algorithm provides a more accurate fitting than the YA algorithm. Therefore, it leads to better performance. Further exploiting this advantage of the proposed derivation, a novel quadrature rule leading to an even better performance than Diethelm's algorithm is proposed. Significant gains in accuracy are achieved at the extreme ends of the frequency range. This results in significant improvements in accuracy for late time responses. Several numerical examples, including fractional differential equations of degree α = 0.3 and α = 1.5, demonstrate the accuracy and efficiency of the proposed method. © Springer-Verlag 2010.
Haynes J.-D.,Charite - Medical University of Berlin |
Haynes J.-D.,Humboldt University of Berlin |
Haynes J.-D.,TU Dresden
Neuron | Year: 2015
Human fMRI signals exhibit a spatial patterning that contains detailed information about a person's mental states. Using classifiers it is possible to access this information and study brain processes at the level of individual mental representations. The precise link between fMRI signals and neural population signals still needs to be unraveled. Also, the interpretation of classification studies needs to be handled with care. Nonetheless, pattern-based analyses make it possible to investigate human representational spaces in unprecedented ways, especially when combined with computational modeling. This review by Haynes provides an introduction to multivoxel pattern analysis (MVPA) of fMRI data. After a methodological overview, Haynes discusses limitations and pitfalls of MVPA techniques and presents emerging directions, such as encoding/decoding models and representational similarity analyses. © 2015 Elsevier Inc.
Gabriel S.A.,University of Maryland University College |
Leuthold F.U.,TU Dresden
Energy Economics | Year: 2010
Many of the European energy markets are characterized by dominant players that own a large share of their respective countries' generation capacities. In addition to that, there is a significant lack of cross-border transmission capacity. Combining both facts justifies the assumption that these dominant players are able to influence the market outcome of an internal European energy market due to strategic behavior. In this paper, we present a mathematical formulation in order to solve a Stackelberg game for a network-constrained energy market using integer programming. The strategic player is the Stackelberg leader and the independent system operator (including the decisions of the competitive fringe firms) acts as follower. We assume that there is one strategic player which results in a mathematical program with equilibrium constraints (MPEC). This MPEC is reformulated as mixed-integer linear program (MILP) by using disjunctive constraints and linearization. The MILP formulation gives the opportunity to solve the problems reliably and paves the way to add discrete constraints to the original MPEC formulation which can be used in order to solve discretely-constrained mathematical programs with equilibrium constraints (DC-MPECs). We report computational results for a small illustrative network as well as a stylized Western European grid with realistic data. © 2009 Elsevier B.V. All rights reserved.
Luxenhofer R.,University of Wurzburg |
Fetsch C.,University of Wurzburg |
Grossmann A.,TU Dresden
Journal of Polymer Science, Part A: Polymer Chemistry | Year: 2013
Precision synthesis of polymers has been a hot topic in recent years. While this is notoriously difficult to address for polymers with a Cï£¿C backbone, Merrifield has discovered a way many decades ago for polypeptides. Using a similar approach, N-substituted polypeptides, so-called polypeptoids have been synthesized and studied for about 20 years. In contrast, the living ring-opening polymerization (ROP) of N-substituted N-carboxyanhydrides was among the first living polymerizations to be discovered. More recently, a surge in new synthetic approaches led to the efficient synthesis of cyclic or linear multiblock copolypeptoids. Thus, polypeptoids can be synthesized either by solid phase synthesis to yield complex and exactly defined oligo- and small polymers or by ROP of appropriately N-substituted N-carboxyanhydrides (NNCA) to give linear, cyclic, or star-like polymers. Together with an excellent biocompatibility, this polymer family may have a bright future ahead as biomaterials. © 2013 Wiley Periodicals, Inc.
Reuter U.,TU Dresden
Integrated Computer-Aided Engineering | Year: 2011
Existence of heterogeneous results for a particular measurement is a typical problem in engineering sciences. This phenomenon represents data uncertainty. It means that a precise specification of a measurement is not possible. Only a non-stochastic dataset is available. In this paper, a new methodology for modelling of such uncertain measurement as fuzzy variable is presented. The membership function for the unknown fuzzy variable is specified using the methods of fuzzy cluster analysis. With the help of these methods, structures in the dataset are identified and the number of elements of the dataset is partitioned into homogeneous subsets. The fuzzy cluster analysis uses gradual membership of elements to subsets. Within the heterogeneous measurement, homogenous subsets are thus detected and the respective membership values of each element to the subsets are determined. The known homogenous subsets and the associated membership values enable the determination of the membership function of the fuzzy variable which models the measurement. The different homogenous subsets are calculable through non-convex characteristics of the membership function. The above mentioned approach is explained with the help of real measured data as well as data resulted from a numerical simulation and is applied on a structural analysis problem. © 2011 - IOS Press and the author(s). All rights reserved.
Thiede C.,TU Dresden
Leukemia | Year: 2015
Mutations in isocitrate dehydrogenases (IDHs) 1 and 2 frequently occur in acute myeloid leukemia (AML) and result in the production of the oncometabolite d-2-hydroxyglutarate (D2HG). D2HG has been shown to promote leukemogenesis even in the absence of mutated IDH, but the prognostic significance of pretreatment serum D2HG levels in patients with IDH-mutated AML is unclear. We measured D2HG serum levels in 84 patients with IDH-mutated AML treated in the prospective, randomized multicenter AML2003 trial of the German Study Alliance Leukemia. Multivariate Cox regression showed D2HG levels to negatively impact on event-free survival (EFS) as a continuous variable in the entire IDHmut cohort (P=0.04), with no effect on overall survival (OS). In a subgroup analysis, the negative impact of D2HG on EFS was found to be restricted to patients with mutations in IDH1 (P=0.003), adjusted for age, leukocyte count, serum lactate dehydrogenase and European LeukemiaNet risk score. We thus conclude that pretreatment D2HG serum levels may yield prognostic information in patients with IDH1-mutated, but not in IDH2-mutated AML, possibly due to different subcellular localizations of IDH1 and IDH2.Leukemia advance online publication, 18 December 2015; doi:10.1038/leu.2015.317. © 2015 Macmillan Publishers Limited
Zuber K.,TU Dresden
Pramana - Journal of Physics | Year: 2012
The physics potential of neutrinoless double beta decay is discussed. Furthermore, experimental considerations as well as the current status of experiments are presented. Finally, an outlook towards the future, work on nuclear matrix elements and alternative processes is given. © Indian Academy of Sciences.
Lozza V.,TU Dresden
Journal of Physics: Conference Series | Year: 2012
The SNO+ experiment is the follow up of the SNO experiment, replacing the heavy water volume with about 780 tons of liquid scintillator (LAB) in order to shift the sensitive threshold to lower energy range. The 6000 m.w.e. natural rock shielding, and the use of ultra-clean materials makes the detector suitable for the detection of pep and CNO solar neutrinos, geo-neutrinos, reactor neutrinos and the possible observation of neutrinos from supernovae. Complementing this program, SNO+ will also search for 150Nd (5.6% abundance) neutrinoless double beta decay, loading the liquid scintillator with 0.1% of natural Neodymium. After a review of the general SNO+ setup, the physics of the solar neutrino phase will be presented.
Odenbach S.,TU Dresden
MRS Bulletin | Year: 2013
In suspensions of magnetic nanoparticles in appropriate carrier liquids - commonly called ferrofluids - an external magnetic field can control the fluid properties such as viscosity. This article provides an overview of the properties and general makeup of ferrofluids, as well as classical fluid dynamics. Some of the applications of ferrofluids are also described. © 2013 Materials Research Society.
Zhu Y.,Nanjing University of Technology |
Fang Y.,Nanjing University of Technology |
Kaskel S.,TU Dresden
Journal of Physical Chemistry C | Year: 2010
Herein we developed a targeted anticancer drug delivery system based on folate-conjugated rattle-type Fe3O4@SiO2 hollow mesoporous spheres combining receptor-mediated targeting and magnetic targeting. Folic acid (FA) ligands were successfully grafted onto rattle-type Fe3O4@SiO2 hollow mesoporous spheres via amide reaction. The magnetization saturation value of folate-conjugated Fe 3O4@SiO2 spheres (Fe3O 4@SiO2-FA) was about 1.6 emu/g, and these spheres could be targeted under an external magnetic field. On the other hand, in vitro cytotoxicity and cell uptake of these Fe3O4@SiO 2-FA spheres to Hela cells were evaluated. These Fe3O 4@SiO2-FA spheres were nontoxic up to a concentration of 150 μg/mL, and further can be specifically taken up by Hela cells via FA receptor-mediated endocytosis. Doxorubicin hydrochloride (DOX), an anticancer drug, was introduced into Fe3O4@SiO2-FA spheres. The release of DOX from Fe3O4@SiO2-FA spheres had a sustained release pattern, and the DOX-loaded Fe3O 4@SiO2-FA spheres exhibited greater cytotoxicity than free DOX and DOX-loaded Fe3O4@SiO2 spheres due to the increase of cell uptake of anticancer drug delivery vehicles mediated by the FA receptor. Therefore, we conclude that folate-conjugated Fe3O 4@SiO2 hollow mesoporous spheres have potential for targeted anticancer drug delivery for cancer therapy. © 2010 American Chemical Society.
Sezgin E.,TU Dresden
Cold Spring Harbor perspectives in biology | Year: 2011
Biological research has always tremendously benefited from the development of key methodology. In fact, it was the advent of microscopy that shaped our understanding of cells as the fundamental units of life. Microscopic techniques are still central to the elucidation of biological units and processes, but equally important are methods that allow access to the dimension of time, to investigate the dynamics of molecular functions and interactions. Here, fluorescence spectroscopy with its sensitivity to access the single-molecule level, and its large temporal resolution, has been opening up fully new perspectives for cell biology. Here we summarize the key fluorescent techniques used to study cellular dynamics, with the focus on lipid and membrane systems.
Dargie W.,TU Dresden
Proceedings - 2012 IEEE 5th International Conference on Cloud Computing, CLOUD 2012 | Year: 2012
Dynamic voltage and frequency scaling (DVFS) has been a useful power management strategy in embedded systems, mobile devices, and wireless sensor networks. Recently, it has also been proposed for servers and data centers in conjunction with service consolidation and optimal resource-pool sizing. In this paper, we experimentally investigate the scope and usefulness of DVFS in a server environment. We set up a multimedia server which will be used in two different scenarios. In the first scenario, the server will host requests to download video files of known and available formats. In the second scenario, videos of unavailable formats can be accepted; in which case the server employs a trans coder to convert between AVI, MPEG and SLV formats before the videos are downloaded. The workload we generate has a uniform arrival rate and an exponentially distributed video size. We use four dynamic scaling policies which are widely used with existing mainstream Linux operating systems. Our observation is that while the gain of DVFS is clear in the first scenario (in which a predominantly IO-bound application is used), its use in the second scenario is rather counterproductive. © 2012 IEEE.
Rachel S.,TU Dresden |
Ezawa M.,University of Tokyo
Physical Review B - Condensed Matter and Materials Physics | Year: 2014
Silicene, germanene, and stanene are two-dimensional topological insulators exhibiting helical edge states. We investigate global and local manipulations at the edges by exposing them to (i) a charge-density-wave order, (ii) a superconductor, (iii) an out-of-plane antiferromagnetic, and (iv) an in-plane antiferromagnetic field. We show that these perturbations affect the helical edge states in a different fashion. As a consequence one can realize quantum spin-Hall effect without edge states. In addition, these edge manipulations lead to very promising applications: a giant magnetoresistance and a perfect spin filter. We also investigate the effect of manipulations on a very few edge sites of a topological insulator nanodisk. © 2014 American Physical Society.
Lubk A.,TU Dresden
Ultramicroscopy | Year: 2014
The reduced density matrix completely describes the quantum state of an electron scattered by an object in transmission electron microscopy. However, the detection process restricts access to the diagonal elements only. The off-diagonal elements, determining the coherence of the scattered electron, may be obtained from electron holography. In order to extract the influence of the object from the off-diagonals, however, a rigorous consideration of the electron microscope influences like aberrations of the objective lens and the Mo¨llenstedt biprism in the presence of partial coherence is required. Here, we derive a holographic transfer theory based on the generalization of the transmission cross-coefficient including all known holographic phenomena. We furthermore apply a particular simplification of the theory to the experimental analysis of aloof beam electrons scattered by plane silicon surfaces. © 2014 Elsevier B.V.
Trolle M.L.,University of Aalborg |
Seifert G.,TU Dresden |
Pedersen T.G.,University of Aalborg
Physical Review B - Condensed Matter and Materials Physics | Year: 2014
Recent experimental results have demonstrated the ability of monolayer MoS2 to efficiently generate second harmonic fields with susceptibilities between 0.1 and 100 nm/V. However, few theoretical calculations exist with which to interpret these findings. In particular, it is of interest to theoretically estimate the modulus of the second harmonic response since experimental reports on this differ by almost three orders of magnitude. Here, we present calculations of the second harmonic response based on a tight-binding band structure and implementation of excitons in a Bethe-Salpeter framework. We compare directly with recent experimental findings demonstrating a good agreement with the excitonic theory regarding, e.g., peak position. Furthermore, we predict an off-resonance susceptibility on the order of 0.1 nm/V, while on-resonance values rise to 4 nm/V. © 2014 American Physical Society.
Phan V.-N.,University of Greifswald |
Becker K.W.,TU Dresden |
Fehske H.,University of Greifswald
Physical Review B - Condensed Matter and Materials Physics | Year: 2010
We explore the spontaneous formation of an excitonic insulator state at the semimetal-semiconductor transition of mixed-valence materials in the framework of the spinless Falicov-Kimball model with direct f-f electron hopping. Adapting the projector-based renormalization method, we obtain a set of renormalization differential equations for the extended Falicov-Kimball model parameters and finally derive analytical expressions for the order parameter, as well as for the renormalized c - and f -electron dispersions, momentum distributions, and wave-vector resolved single-particle spectral functions. Our numerical results proved the valence transition picture, related to the appearance of the excitonic insulator phase, in the case of overlapping c and f bands. Thereby the photoemission spectra show significant differences between the weak-to-intermediate and intermediate-to-strong Coulomb attraction regimes, indicating a BCS-Bose-Einstein transition of the excitonic condensate. © 2010 The American Physical Society.
Elste F.,Columbia University |
Timm C.,TU Dresden
Physical Review B - Condensed Matter and Materials Physics | Year: 2010
Transport through molecular magnets is studied in the regime of strong coupling to the leads. We consider a resonant-tunneling model where the electron spin in a quantum dot or molecule is coupled to an additional local, anisotropic spin via exchange interaction. The two opposite regimes dominated by resonant tunneling and by Kondo transport, respectively, are considered. In the resonant-tunneling regime, the stationary state of the impurity spin is calculated for arbitrarily strong molecule-lead coupling using a master-equation approach, which treats the exchange interaction perturbatively. We find that the characteristic fine structure in the differential conductance persists even if the hybridization energy exceeds thermal energies. Transport in the Kondo regime is studied within a diagrammatic approach. We show that magnetic anisotropy gives rise to the appearance of two Kondo peaks at nonzero bias voltages. © 2010 The American Physical Society.
Wozel G.,TU Dresden |
Archives of Dermatological Research | Year: 2014
Dapsone (4,4′-diaminodiphenylsulfone) is an aniline derivative belonging to the group of synthetic sulfones. In 1937 against the background of sulfonamide era the microbial activity of dapsone has been discovered. Shortly thereafter, the use of dapsone to treat non-pathogen-caused diseases revealed alternate antiinflammatory mechanisms that initially were elucidated by inflammatory animal models. Thus, dapsone clearly has dual functions of both: antimicrobial/antiprotozoal effects and anti-inflammatory features similarly to non-steroidal anti-inflammatory drugs. The latter capabilities primarily were used in treating chronic inflammatory disorders. Dapsone has been investigated predominantly by in vitro methods aiming to get more insights into the effect of dapsone to inflammatory effector cells, cytokines, and/or mediators, such as cellular toxic oxygen metabolism, myoloperoxidase-/halogenid system, adhesion molecules, chemotaxis, membrane-associated phospholipids, prostaglandins, leukotrienes, interleukin-8, tumor necrosis factor α, lymphocyte functions, and tumor growth. Moreover, attention has been paid to mechanisms by which dapsone mediates effects in more complex settings like impact of lifespan, stroke, glioblastoma, or as anticonvulsive agent. Additionally, there are some dermatological investigations in human being using dapsone and its metabolites (e.g., leukotriene B4-induced chemotaxis, ultraviolet-induced erythema). It could be established that dapsone metabolites by their own have anti-inflammatory properties. Pharmacology and mechanisms of action are determining factors for clinical use of dapsone chiefly in neutrophilic and/or eosinophilic dermatoses and in chronic disorders outside the field of dermatology. The steroid-sparing effect of dapsone is useful for numerous clinical entities. Future avenues of investigations will provide more information on this fascinating and essential agent. © 2013 The Author(s).
Kuc A.,Jacobs University Bremen |
Heine T.,Jacobs University Bremen |
Seifert G.,TU Dresden
Physical Review B - Condensed Matter and Materials Physics | Year: 2010
The structures, cohesive energies, and highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) gaps of graphene nanoflakes and corresponding polycyclic aromatic hydrocarbons for a large variety of size and topology are investigated at the density-functional-based tight-binding level. Polyacenelike and honeycomblike graphene nanoflakes were chosen as the topological limit structures. The influence of unsaturated edge atoms and dangling bonds on the stability is discussed. Our survey shows a linear trend for the cohesive energy as function of Ns/N (N -total number of atoms and Ns is number of edge atoms). For the HOMO-LUMO gap the trends are more complex and include also the topology of the edges. © 2010 The American Physical Society.
de Celis M.F.R.,TU Dresden
Molecular Psychiatry | Year: 2016
The brain and adrenal are critical control centers that maintain body homeostasis under basal and stress conditions, and orchestrate the body’s response to stress. It is noteworthy that patients with stress-related disorders exhibit increased vulnerability to mental illness, even years after the stress experience, which is able to generate long-term changes in the brain's architecture and function. High levels of glucocorticoids produced by the adrenal cortex of the stressed subject reduce neurogenesis, which contributes to the development of depression. In support of the brain–adrenal connection in stress, many (but not all) depressed patients have alterations in the components of the limbic-hypothalamic-pituitary-adrenal (LHPA) axis, with enlarged adrenal cortex and increased glucocorticoid levels. Other psychiatric disorders, such as post-traumatic stress disorder, bipolar disorder and depression, are also associated with abnormalities in hippocampal volume and hippocampal function. In addition, hippocampal lesions impair the regulation of the LHPA axis in stress response. Our knowledge of the functional connection between stress, brain function and adrenal has been further expanded by two recent, independent papers that elucidate the effects of stress on brain and adrenal stem cells, showing similarities in the way that the progenitor populations of these organs behave under stress, and shedding more light into the potential cellular and molecular mechanisms involved in the adaptation of tissues to stress.Molecular Psychiatry advance online publication, 26 January 2016; doi:10.1038/mp.2015.230. © 2016 Macmillan Publishers Limited
Fettweis G.,TU Dresden |
Alamouti S.,Mobile Wireless Group
IEEE Communications Magazine | Year: 2014
Cellular technology has dramatically changed our society and the way we communicate. First it impacted voice telephony, and then has been making inroads into data access, applications, and services. However, today potential capabilities of the Internet have not yet been fully exploited by cellular systems. With the advent of 5G we will have the opportunity to leapfrog beyond current Internet capabilities. © 2014 IEEE.
Shen L.,TU Dresden
Computers and Industrial Engineering | Year: 2014
This paper addresses the classic job shop scheduling problem where sequence dependent setup times are present. Based on a modified disjunctive graph, we further investigate and generalize structural properties for the problem under study. A tabu search algorithm with a sophisticated neighbourhood structure is then developed. Compared to most studies in this research area, we are interested in moving internal critical operations rather than merely focusing on non-internal ones. Moreover, neighbourhood functions are defined using insertion techniques instead of simple swaps. Test results show that our algorithm outperforms a simulated annealing algorithm which is recently published. We have also conducted experiments considering the efficiency of developed propositions. © 2014 Elsevier Ltd.
Festag A.,TU Dresden
IEEE Communications Magazine | Year: 2014
Information exchange among vehicles, and between vehicles and the roadside infrastructure is commonly regarded as a base technology to sustainably reduce road accidents and improve traffic efficiency. After more than a decade of research and development efforts, a technological basis has been established that applies WiFi-based, wireless communication in the 5.9 GHz frequency band, ad hoc communication and dedicated message sets, as well as management and security procedures. In Europe, Release 1 of standards for cooperative systems has been completed, indicating deployment of a basic system starting in 2015. This article provides a comprehensive overview of standards and complementary industry specifications for cooperative systems in Europe, covering relevant aspects of access technologies, network and transport protocols, facilities, applications, security, and management. © 2014 IEEE.
Fei J.-F.,Max Planck Institute of Molecular Cell Biology and Genetics |
Fei J.-F.,TU Dresden |
Haffner C.,Max Planck Institute of Molecular Cell Biology and Genetics |
Huttner W.B.,Max Planck Institute of Molecular Cell Biology and Genetics
Cell Reports | Year: 2014
Mammalian neocortex size primarily reflects the number and mode of divisions of neural stem and progenitor cells. Cortical stem cells (apical progenitors) switching from symmetric divisions, which expand their population, to asymmetric divisions, which generate downstream neuronal progenitors (basal progenitors), start expressing Tis21, a so-called antiproliferative/prodifferentiative gene. Tis21 encodes a small (17.5kDa), functionally poorly characterized protein and a relatively large (2 kb), highly conserved 3' UTR. Here, we show that mice lacking the Tis21 3' UTR develop a microcephalic neocortex with fewer neurons, notably in the upper layers. This reflects a progressive decrease in basal progenitors, which in turn is due to a fraction of apicalprogenitors prematurely switching from asymmetric self-renewing to symmetric self-consuming divisions. This switch is caused by the markedly increased Tis21 protein level resulting from lack of microRNA-, notably miR-92-, dependent restriction of Tis21 expression. Our data show that a premature onset of consumptive neural stem cell divisions can lead to microcephaly. © 2014 The Authors.
Laugsch M.,TU Dresden
Molecular Therapy | Year: 2015
Chronic granulomatous disease (CGD) is an inherited immunodeficiency, caused by the inability of neutrophils to produce functional NADPH oxidase required for fighting microbial infections. The X-linked form of CGD (X-CGD), which is due to mutations in the CYBB (gp91phox) gene, a component of NADPH oxidase, accounts for about two-thirds of CGD cases. We derived induced pluripotent stem cells (iPSCs) from X-CGD patient keratinocytes using a Flp recombinase excisable lentiviral reprogramming vector. For restoring gp91phox function, we applied two strategies: transposon-mediated bacterial artificial chromosome (BAC) transgenesis and gene targeting using vectors with a fixed 5′ homology arm (HA) of 8 kb and 3′HA varying in size from 30 to 80 kb. High efficiency of homologous recombination (up to 22%) was observed with increased size of the 3′HA. Both, BAC transgenesis and gene targeting resulted in functional restoration of the gp91phox measured by an oxidase activity assay in X-CGD iPSCs differentiated into the myeloid lineage. In conclusion, we delivered an important milestone towards the use of genetically corrected autologous cells for the treatment of X-CGD and monogenic diseases in general.Molecular Therapy (2015); doi:10.1038/mt.2015.154. © 2015 Official journal of the American Society of Gene & Cell Therapy
Vad T.,TU Dresden |
Sager W.F.C.,Julich Research Center
Journal of Applied Crystallography | Year: 2011
Two simple iterative desmearing procedures - the Lake algorithm and the Van Cittert method - have been investigated by introducing different convergence criteria using both synthetic and experimental small-angle neutron scattering data. Implementing appropriate convergence criteria resulted in stable and reliable solutions in correcting resolution errors originating from instrumental smearing, i.e. finite collimation and polychromaticity of the incident beam. Deviations at small momentum transfer for concentrated ensembles of spheres encountered in earlier studies are not observed. Amplification of statistical errors can be reduced by applying a noise filter after desmearing. In most cases investigated, the modified Lake algorithm yields better results with a significantly smaller number of iterations and is, therefore, suitable for automated desmearing of large numbers of data sets. © 2011 International Union of Crystallography Printed in Singapore-all rights reserved.
Tribelsky M.I.,TU Dresden
EPL | Year: 2011
Light absorption by a spatially uniform spherical nanoparticle in the vicinity of surface plasmon (polariton) resonances is studied in detail based on the exact Mie solution. It is shown that the maximal absorption is achieved for a particle from weakly dissipating materials and may have very unusual properties. A simple universal formula describing the resonant absorption lineshape as a function of the particle size and its complex dielectric permittivity is obtained. Possible comparison with experiment is discussed. © 2011 Europhysics Letters Association.
Bauer A.,TU Dresden
Current Opinion in Allergy and Clinical Immunology | Year: 2013
PURPOSE OF REVIEW: The review summarizes recent findings on contact dermatitis in the cleaning industry. RECENT FINDINGS: Contact dermatitis is still an important issue in cleaning. Recent studies identified cleaning work sites and tasks, as well as specific cleaning products, which incur a risk increase for occupational contact dermatitis in cleaning. Workers involved in cleaning outdoors prevalence ratio [PR 1.85, 95% confidence interval (CI) 1.16-2.96], cleaning common areas of residential buildings (PR 1.77, 95% CI 1.11-2.84), schools (PR 1.84, 95% CI 1.15-2.93) and cleaning building sites (PR 1.87, 95% CI 1.18-2.95) showed significantly higher rates of contact dermatitis. Relevant allergens in cleaning are rubber chemicals and disinfectants. Leading allergens are thiurams (11.6%, 95% CI 9.1-14.1) and formaldehyde (3.4%, 95% CI 2.0-4.7), but contact with metal allergens might also be important. The most likely allergen sources for sensitization against rubber chemicals are protective gloves. High sensitization rates for disinfectants might result from the fact that employees in cleaning often use single-use medical examination gloves while cleaning. These gloves are not resistant to chemicals, which may break through the gloves within a short period of time, depending on glove material and thickness. No differences in sensitization rates and sensitization profiles were seen in cleaners of younger (≤40 years) and older (>40 years) age. SUMMARY: Prevalence of occupational contact dermatitis is still high in cleaning. Irritant contact dermatitis is prevailing, but allergic contact dermatitis is quite frequent, too. Up to now, prevention strategies in cleaning seem to be insufficient. © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins.
Eisenhofer G.,TU Dresden
Current Hypertension Reports | Year: 2012
Pheochromocytomas and paragangliomas are highly heterogeneous neuroendocrine tumors that must be considered not only in patients with hypertension and other manifestations of catecholamine excess but also in patients with incidentalomas or mutations in one of the ten tumor susceptibility genes identified to date. To first think of the tumor remains the critical step for screening in patients with signs and symptoms. In these patients, biochemical testing is straightforward and should include measurements of plasma or urinary metanephrines, comprising separately measured normetanephrine and metanephrine. Tumors due to an underlying germline mutation are often found in the absence of hypertension or other signs or symptoms of the tumor. Screening for disease in these patients can benefit from an individualized approach according to the particular mutation. Additional measurements of methoxytyramine, the metabolite of dopamine, can be useful in patients with mutations of succinate dehydrogenase genes or patients who are at risk for malignancy. © Springer Science+Business Media, LLC 2012.
Aland S.,TU Dresden
Journal of Computational Physics | Year: 2014
We propose a variant of the θ-scheme for diffuse interface models for two-phase flow, together with three new linearization techniques for the surface tension. These involve either additional stabilizing force terms, or a fully implicit coupling of the Navier-Stokes and Cahn-Hilliard equation. In the common case that the equations for interface and flow are coupled explicitly, we find a time step restriction which is very different to other two-phase flow models and in particular is independent of the grid size. We also show that the proposed stabilization techniques can lift this time step restriction.Even more pronounced is the performance of the proposed fully implicit scheme which is stable for arbitrarily large time steps. We demonstrate in a Taylor-flow application that this superior coupling between flow and interface equation can decrease the computation time by several orders of magnitude. © 2014 Elsevier Inc.
Lessmann C.,TU Dresden
Environment and Planning A | Year: 2012
This paper analyzes the impact of political and fiscal decentralization on regional inequalities, using a unique dataset which covers fifty-four countries at diff erent stages of economic development. Cross-section and panel data estimations show that decentralization decreases regional inequalities in general. However, estimations using an interactionvariable approach imply that the eff ect depends on the level of economic development. While rich countries benefit from decentralization in that they achieve a more equal regional income distribution, decentralization may lead to higher regional inequalities in developing and emerging economies. The results point in the same direction for measures of fiscal and political decentralization, implying that autonomy in both decision making and fiscal authority are decisive in this context. Thus, when fostering decentralization in developing countries as proposed by international development agencies, the potential negative redistributional consequences should be taken into account. © 2012 Pion and its Licensors.
Almedawar M.M.,TU Dresden
Current Opinion in Cardiology | Year: 2016
PURPOSE OF REVIEW: Smoking tobacco using a water pipe is becoming more prevalent globally, particularly amongst younger populations. In addition to its growing popularity, more evidence is emerging regarding associated harm, and several misconceptions exist concerning the likely adverse health effects of waterpipe smoking (WPS). It is timely, therefore, to examine the body of evidence linking WPS to coronary artery disease (CAD). Here, we review the direct evidence linking WPS to CAD and examine additional, indirect evidence of associated harm. We discuss the clinical and public health implications of the current evidence and provide suggestions for further research. RECENT FINDINGS: A multicentre case–control study in Lebanon has recently demonstrated an association between WPS and CAD. There are few prior studies making this direct link. However, a large body of evidence has emerged showing close similarities between WPS and cigarette smoking with regard to the toxicity of smoke and acute inflammatory and haemodynamic effects following exposure to it. SUMMARY: There are consistent similarities between WPS and cigarette smoking in regard to association with CAD, the nature of the smoke produced, and the acute haemodynamic effects and inflammatory responses that follow exposure. These findings justify both public health and clinical interventions to reduce WPS. Further studies are warranted to confirm a causal association between WPS and CAD. Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.
Zillmann P.,TU Dresden
IEEE Signal Processing Letters | Year: 2010
Memoryless nonlinear transforms of random signals with Gaussian statistics are encountered in a variety of signal processing applications. A well-known criterion for the description of distortion errors is the Mean Squared Error (MSE) between the input and output signals of the nonlinearity. A different criterion which has been found to be useful especially in the field of multicarrier communications is the Signal-to-Distortion Noise Ratio (SDNR), which is based on the bussgang decomposition of the output of the nonlinearity. It is shown that the SDNR optimum coincides with the minimum MSE solution, which simplifies the optimization of memoryless nonlinear functions with respect to SDNR. The results are applied to quantization and dynamic range reduction of Gaussian signals. © 2010 IEEE.
Dickreuter E.,TU Dresden
Oncogene | Year: 2015
β1 Integrin-mediated cell–extracellular matrix interactions allow cancer cell survival and confer therapy resistance. It was shown that inhibition of β1 integrins sensitizes cells to radiotherapy. Here, we examined the impact of β1 integrin targeting on the repair of radiation-induced DNA double-strand breaks (DSBs). β1 Integrin inhibition was accomplished using the monoclonal antibody AIIB2 and experiments were performed in three-dimensional cell cultures and tumor xenografts of human head and neck squamous cell carcinoma (HNSCC) cell lines. AIIB2, X-ray irradiation, small interfering RNA-mediated knockdown and Olaparib treatment were performed and residual DSB number, protein and gene expression, non-homologous end joining (NHEJ) activity as well as clonogenic survival were determined. β1 Integrin targeting impaired repair of radiogenic DSB (γH2AX/53BP1, pDNA-PKcs T2609 foci) in vitro and in vivo and reduced the protein expression of Ku70, Rad50 and Nbs1. Further, we identified Ku70, Ku80 and DNA-PKcs but not poly(ADP-ribose) polymerase (PARP)-1 to reside in the β1 integrin pathway. Intriguingly, combined inhibition of β1 integrin and PARP using Olaparib was significantly more effective than either treatment alone in non-irradiated and irradiated HNSCC cells. Here, we support β1 integrins as potential cancer targets and highlight a regulatory role for β1 integrins in the repair of radiogenic DNA damage via classical NHEJ. Further, the data suggest combined targeting of β1 integrin and PARP as promising approach for radiosensitization of HNSCC.Oncogene advance online publication, 15 June 2015; doi:10.1038/onc.2015.212. © 2015 Macmillan Publishers Limited
Kreslavsky T.,Dana-Farber Cancer Institute |
Gleimer M.,Dana-Farber Cancer Institute |
Garbe A.I.,TU Dresden |
von Boehmer H.,Dana-Farber Cancer Institute
Immunological Reviews | Year: 2010
Both αβ and γδ T cells develop in the thymus from a common progenitor. Historically distinguished by their T-cell receptor (TCR), these lineages are now defined on the basis of distinct molecular programs. Intriguingly, in many transgenic and knockout systems these programs are mismatched with the TCR type, leading to the development of γδ lineage cells driven by αβTCR and vice versa. These puzzling observations were recently explained by the demonstration that TCR signal strength, rather than TCR type per se, instructs lineage fate, with stronger TCR signal favoring γδ and weaker signal favoring αβ lineage fates. These studies also highlighted the ERK (extracellular signal regulated kinase)-Egr (early growth response)-Id3 (inhibitor of differentiation 3) axis as a potential molecular switch downstream of TCR that determines lineage choice. Indeed, removal of Id3 was sufficient to redirect TCRγδ transgenic cells to the αβ lineage, even in the presence of strong TCR signal. However, in TCR non-transgenic Id3 knockout mice the overall number of γδ lineage cells was increased due to an outgrowth of a Vγ1Vδ6.3 subset, suggesting that not all γδ T cells depend on this molecular switch for lineage commitment. Thus, the γδ lineage may in fact be a collection of two or more lineages not sharing a common molecular program and thus equipollent to the αβ lineage. TCR signaling is not the only factor that is required for development of αβ and γδ lineage cells; other pathways, such as signaling from Notch and CXCR4 receptors, cooperate with the TCR in this process. © 2010 John Wiley & Sons A/S.
Plagge R.,TU Dresden
Materials and Structures/Materiaux et Constructions | Year: 2011
Due to limits in current moisture content and moisture potential measurement technology, moisture transport is normally investigated under equilibrium conditions. Most processes we observe in nature are, however, transient and hardly ever reach an equilibrium stage. This means that future experimental methods in moisture transport investigation will focus on transient processes. One such method is the instantaneous profile measurement (IPM) technique frequently used in soil science. It can be applied to investigate moisture transport under transient conditions. Two measurement principles are combined in one material to record data for moisture content and moisture potential at the same time and at various points. As output, moisture content and moisture potential profiles are plotted against space and time. The method was applied to different porous materials, and hygroscopic loading and deloading cycles were conducted in the relative humidity range between 30 and 97%. The data obtained is not in strict agreement with static or steady-state observations. This reveals information about moisture transport kinetics. These findings are discussed in the context of the literature and with regard to their significance for current moisture transport models, which are typically based on equilibrium data. © RILEM 2010.
Zvyagin A.A.,TU Dresden |
Zvyagin A.A.,Ukrainian Academy of Sciences
Physical Review B - Condensed Matter and Materials Physics | Year: 2010
We propose an analytical ansatz, using which the ordering temperature of a quasi-one-dimensional (quasi-1D) antiferromagnetic (AF) system (weakly coupled quantum spin-1/2 chains) in the presence of the external magnetic field is calculated. The field dependence of the critical exponents for correlation functions of 1D subsystems plays a very important role. It determines the region of possible re-entrant phase transition, governed by the field. It is shown how the quantum-critical point between two phases of the 1D subsystem, caused by spin-frustrating next-nearest neighbor and multispin ringlike exchanges, affects the field dependence of the ordering temperature. Our results qualitatively agree with the features, observed in experiments on quasi-1D AF systems. © 2010 The American Physical Society.
Weber G.F.,TU Dresden |
Swirski F.K.,Harvard University
Langenbeck's Archives of Surgery | Year: 2014
Background: Sepsis is an unsolved problem worldwide, with a 30-50 % mortality rate. The recent failures of anti-TLR4, recombinant activated protein C, and anti-TNF in clinical trials indicate a need to rethink our current understanding of sepsis's pathophysiology. While the initial immune response is crucial for effective clearance of invading pathogens, an overly exuberant host response to infection can cause septic shock, tissue damage, and death. Profuse inflammation in sepsis is frequently followed by global immunosuppression that increases susceptibility to viral and bacterial infections. Despite the dangers of immune over-response, the immune system's anti-inflammatory activities are likely necessary to reduce the initial over-activation of the immune system. Purpose: With this review, we want to illuminate the different aspects of immune response to sepsis and provide insight to the ongoing difficulties currently present within sepsis research. Conclusion: Future treatment strategies for sepsis should focus on maintaining balance between pro- and anti-inflammatory immune actions in a timely manner. © 2013 Springer-Verlag Berlin Heidelberg.
Petrasek Z.,TU Dresden
Methods in enzymology | Year: 2010
Scanning fluorescence correlation spectroscopy (sFCS) is the generic term for a group of fluorescence correlation techniques where the measurement volume is moved across the sample in a defined way. The introduction of scanning is motivated by its ability to alleviate or remove several distinct problems often encountered in standard FCS, and thus, to extend the range of applicability of fluorescence correlation methods in biological systems. These problems include poor statistical accuracy in measurements with slowly moving molecules, photobleaching, optical distortions affecting the calibration of the measurement volume, membrane instabilities, etc. Here, we present an overview of sFCS methods, explaining their benefits, implementation details, requirements, and limitations, as well as relations to each other. Further, we give examples of different sFCS implementations as applied to cellular systems, namely large-circle sFCS to measure protein dynamics in embryo cortex and line sFCS to measure protein diffusion and interactions in unstable membranes. Copyright 2010 Elsevier Inc. All rights reserved.
Cordes N.,TU Dresden
Strahlentherapie und Onkologie : Organ der Deutschen Röntgengesellschaft ... [et al] | Year: 2012
This brief summary on the role of experimental radiation oncology highlights several new research topics and research approaches that offer great potential for the optimization of modern radiation oncology. In addition, many areas of research, such as hypoxia, angiogenesis, the immune system, and metabolism, to name a few, comprise a substantial part of our current knowledge of tumor and radiation biology. Which new insights and therapeutic possibilities via the Human Cancer Genome Project or new processes, such as next generation sequencing may offer, cannot be easily foreseen at present. However, we do know for certain: radiation biology has and will continue to contribute to improvements in radiation oncology.
Pischetsrieder M.,Friedrich - Alexander - University, Erlangen - Nuremberg |
Henle T.,TU Dresden
Amino Acids | Year: 2012
Infant formulas are milk-based products, which are adapted to the composition of human milk. To ensure microbiological safety and long shelf life, infant formulas usually undergo rigid heat treatment. As a consequence of the special composition and the heat regimen, infant formulas are more prone to thermally induced degradation reactions than regular milk products. Degradation reactions observed during milk processing comprise lactosylation yielding the Amadori product lactulosyllysine, the formation of advanced glycation end products (AGEs), and protein-free sugar degradation products, as well as protein or lipid oxidation. Several methods have been developed to estimate the heat impact applied during the manufacturing of infant formulas, including indirect methods such as fluorescence analysis as well as the analysis of defined reaction products. Most studies confirm a higher degree of damage in infant formulas compared to regular milk products. Differences between various types of infant formulas, such as liquid, powdered or hypoallergenic formulas depend on the analyzed markers and brands. A considerable portion of protein degradation products in infant formulas can be avoided when process parameters and the quality of the ingredients are carefully controlled. The nutritional consequences of thermal degradation products in infant formulas are largely unknown. © Springer-Verlag 2010.
Pradhan B.,TU Dresden
Journal of the Indian Society of Remote Sensing | Year: 2010
Geospatial database creation for landslide susceptibility mapping is often an almost inhibitive activity. This has been the reason that for quite some time landslide susceptibility analysis was modelled on the basis of spatially related factors. This paper presents the use of frequency ratio, fuzzy logic and multivariate regression models for landslide susceptibility mapping on Cameron catchment area, Malaysia, using a Geographic Information System (GIS) and remote sensing data. Landslide locations were identified in the study area from the interpretation of aerial photographs, high resolution satellite images, inventory reports and field surveys. Topographical, geological data and satellite images were collected, processed, and constructed into a spatial database using GIS and image processing tools. There were nine factors considered for landslide susceptibility mapping and the frequency ratio coefficient for each factor was computed. The factors chosen that influence landslide occurrence were: topographic slope, topographic aspect, topographic curvature and distance from drainage, all from the topographic database; lithology and distance from lineament, taken from the geologic database; land cover from TM satellite image; the vegetation index value from Landsat satellite images; and precipitation distribution from meteorological data. Using these factors the fuzzy membership values were calculated. Then fuzzy operators were applied to the fuzzy membership values for landslide susceptibility mapping. Further, multivariate logistic regression model was applied for the landslide susceptibility. Finally, the results of the analyses were verified using the landslide location data and compared with the frequency ratio, fuzzy logic and multivariate logistic regression models. The validation results showed that the frequency ratio model (accuracy is 89%) is better in prediction than fuzzy logic (accuracy is 84%) and logistic regression (accuracy is 85%) models. Results show that, among the fuzzy operators, in the case with "gamma" operator (λ = 0. 9) showed the best accuracy (84%) while the case with "or" operator showed the worst accuracy (69%). © 2010 Indian Society of Remote Sensing.
Wozel V.E.G.,TU Dresden
Dermatologic Clinics | Year: 2010
After synthesis of dapsone (4,4' diaminodiphenylsulfone) in 1908, the compound was known exclusively in chemistry. Following the epoch-making discovery of the antimicrobial potential for sulfonamides emerged, the sulfone class was included in the medical armamentarium. The therapeutic role of sulfones related to both pathogen-caused diseases and chronic inflammatory dermatoses has led to extensive use in dermatology. At present dapsone is the only sulfone congener available for clinical practice. The sulfone is used in rifampin-based multiple-drug regiments to treat multibacillary and paucibacillary leprosy and to treat . Pneumocystis jiroveci pneumonia and prevent toxoplasmosis in individuals with AIDS. In dermatology, dapsone is the preferred drug for treating dermatitis herpetiformis (Duhring's disease) and is useful in the management of a broad range of chronic inflammatory entities, especially autoimmune bullous disorders. With proper administration and monitoring, the sulfone should be considered a useful and safe agent. © 2010 Elsevier Inc.
Bschor T.,Jewish Hospital of Berlin |
Bschor T.,TU Dresden |
Baethge C.,University of Cologne
Acta Psychiatrica Scandinavica | Year: 2010
Objective: Switching antidepressants is a common strategy for managing treatment-resistant depressed patients. However, no systematic reviews have been conducted to date. Method: We systematically searched MEDLINE/EMBASE/Cochrane Central Register of Controlled Trials and additional sources. We included double-blind studies of patients with depressive symptomatology who were not responding to initial antidepressant monotherapy and were subsequently randomized to another antidepressant or to continue the same antidepressant. Results were pooled for meta-analysis of response + remission rates using a fixed-effects model. Results: A total of three studies were included. Switching to another antidepressant was not superior to continuing the initial antidepressant in any of these studies. Our meta-analysis showed no significant advantages to either strategy and no significant heterogeneity of results [OR for response rates: 0.85 (95% CI: 0.55-1.30) favoring continuing]. Conclusion: There is a discrepancy between the published evidence and the frequent decision to switch antidepressants, indicating an urgent need for more controlled studies. Pending such studies we recommend that physicians rely on more thoroughly evaluated strategies. © 2009 John Wiley & Sons A/S.
Perez M.A.,Federico Santa Maria Technical University |
Bernet S.,TU Dresden |
Rodriguez J.,Federico Santa Maria Technical University |
Kouro S.,Federico Santa Maria Technical University |
Lizana R.,Federico Santa Maria Technical University
IEEE Transactions on Power Electronics | Year: 2015
Modular multilevel converters have several attractive features such as a modular structure, the capability of transformer-less operation, easy scalability in terms of voltage and current, low expense for redundancy and fault tolerant operation, high availability, utilization of standard components, and excellent quality of the output waveforms. These features have increased the interest of industry and research in this topology, resulting in the development of new circuit configurations, converter models, control schemes, and modulation strategies. This paper presents a review of the latest achievements of modular multilevel converters regarding the mentioned research topics, new applications, and future trends. © 2014 IEEE.
Zuber K.,TU Dresden
Nuclear and Particle Physics Proceedings | Year: 2015
The Helium and Lead Observatory (HALO) is a new supernova neutrino detector at SNOLAB base on neutrino reactions on lead. Currently it is the only detector whose signal is dominated by the νe component of supernova neutrinos. A short description of the detector and its current status are given. © 2015.
Monti P.,San Raffaele Scientific Institute |
Bonifacio E.,TU Dresden
Current Diabetes Reports | Year: 2014
Antigen-experienced T-cells directly target and destroy insulin-producing beta cells in patients with Type 1 diabetes. Consequently, T-cells are also major targets of immunomodulatory strategies that aim to prevent or delay the immune mediated loss of islet beta-cell function. These strategies have had modest success, prompting efforts into better defining the mechanisms that drive the differentiation of quiescent autoreactive clones into pathogenic effector and memory T-cells. Recent and novel findings now indicate that in addition to the classic mechanisms of antigenic recognition, autoreactive T-cell differentiation and expansion can be boosted by the homeostatic cytokine interleukin-7. In this article, we discuss recent evidence of the role of IL-7 mediated T-cell proliferation in the pathogenesis of Type 1 diabetes and the rationale for including immunomodulatory molecules targeting the IL-7/IL-7R axis in immunotherapeutic strategies to control beta-cell autoimmunity. © Springer Science+Business Media 2014.
Fabian J.,TU Dresden
Dyes and Pigments | Year: 2010
To examine the strengths and limitations of the time-dependent density functional theory in calculating the absorption wavelengths of dye, 130, non-radical, radical and biradical coloured organic compounds, including perylenimide, porphyrin, azobenzene, quinone, croconaine, squaraine and push-pull-type colorants, were randomly selected. The first intense electronic transitions were satisfactorily calculated using time-dependent density functional theory. Whilst polymethine dyes behaved exceptionally, the calculated transition energies for cyanines, oxonols and various related dyes were systematically too large. Broken-symmetry unrestricted density functional calculations revealed the biradical character of several quinoid compounds derived from p-quinodimethane as well as that of some non-Kekulé-type structures. © 2009 Elsevier Ltd. All rights reserved.
Yurchenko S.N.,TU Dresden |
Barber R.J.,University College London |
Tennyson J.,University College London
Monthly Notices of the Royal Astronomical Society | Year: 2011
We present 'BYTe', a comprehensive 'hot' line list for the ro-vibrational transitions of ammonia, 14NH 3, in its ground electronic state. This line list has been computed variationally using the program suite trove, a new spectroscopically determined potential energy surface and an ab initio dipole moment surface. BYTe, is designed to be used at all temperatures up to 1500K. It comprises 1138323351 transitions in the frequency range from 0 to 12000cm -1, constructed from 1373897 energy levels below 18000cm -1 having J values ≤36. Comparisons with laboratory data confirm the accuracy of the line list which is suitable for modelling a variety of astrophysical problems including the atmospheres of extrasolar planets and brown dwarfs. © 2011 The Authors. Monthly Notices of the Royal Astronomical Society © 2011 RAS.
Eisenhofer G.,TU Dresden |
Peitzsch M.,Institute of Clinical Chemistry and Laboratory Medicine and
Clinical chemistry | Year: 2014
BACKGROUND: Pheochromocytomas and paragangliomas (PPGLs) are potentially lethal yet usually surgically curable causes of endocrine hypertension; therefore, once clinical suspicion is aroused it is imperative that clinicians choose the most appropriate laboratory tests to identify the tumors.CONTENT: Compelling evidence now indicates that initial screening for PPGLs should include measurements of plasma free metanephrines or urine fractionated metanephrines. LC-MS/MS offers numerous advantages over other analytical methods and is the method of choice when measurements include methoxytyramine, the O-methylated metabolite of dopamine. The plasma test offers advantages over the urine test, although it is rarely implemented correctly, rendering the urine test preferable for mainstream use. To ensure optimum diagnostic sensitivity for the plasma test, reference intervals must be established for blood samples collected after 30 min of supine rest and after an overnight fast when measurements include methoxytyramine. Similarly collected blood samples during screening, together with use of age-adjusted reference intervals, further minimize false-positive results. Extents and patterns of increases in plasma normetanephrine, metanephrine, and methoxytyramine can additionally help predict size and adrenal vs extraadrenal locations of tumors, as well as presence of metastases and underlying germline mutations of tumor susceptibility genes.SUMMARY: Carried out correctly at specialist endocrine centers, collection of blood for measurements of plasma normetanephrine, metanephrine, and methoxytyramine not only provides high accuracy for diagnosis of PPGLs, but can also guide clinical decision-making about follow-up imaging strategies, genetic testing, and therapeutic options. At other centers, measurements of urine fractionated metanephrines will identify most PPGLs. © 2014 American Association for Clinical Chemistry.
Liao L.,Palo Alto Research Center PARC |
Kottig F.,TU Dresden |
Kottig F.,Siemens AG
IEEE Transactions on Reliability | Year: 2014
Prognostics focuses on predicting the future performance of a system, specifically the time at which the system no long performs its desired functionality, its time to failure. As an important aspect of prognostics, remaining useful life (RUL) prediction estimates the remaining usable life of a system, which is essential for maintenance decision making and contingency mitigation. A significant amount of research has been reported in the literature to develop prognostics models that are able to predict a system's RUL. These models can be broadly categorized into experience-based models, date-driven models, and physics-based models. However, due to system complexity, data availability, and application constraints, there is no universally accepted best model to estimate RUL. The review part of this paper specifically focused on the development of hybrid prognostics approaches, attempting to leverage the advantages of combining the prognostics models in the aforementioned different categories for RUL prediction. The hybrid approaches reported in the literature were systematically classified by the combination and interfaces of various types of prognostics models. In the case study part, a hybrid prognostics method was proposed and applied to a battery degradation case to show the potential benefit of the hybrid prognostics approach. © 2014 IEEE.
Vo D.N.,Ho Chi Minh City University of Technology |
Schegner P.,TU Dresden |
Ongsakul W.,Asian Institute of Technology
IET Generation, Transmission and Distribution | Year: 2013
This study proposes a cuckoo search algorithm (CSA) for solving non-convex economic dispatch (ED) considering generator and system characteristics including valve-point effects, multiple fuels, prohibited zones, spinning reserve and power loss. CSA is a new meta-heuristic optimisation method inspired from the obligate brood parasitism of some cuckoo species by laying their eggs in the nests of other host birds of other species. When the host birds discover an alien egg in their nest, they can either throw it away or simply abandon their nest and build a new one elsewhere. The CSA idealised such breeding behaviour in combination with Lévy flights behaviour of some birds and fruit flies for applying to various constrained optimisation problems. The effectiveness of the proposed method has been tested on different non-convex ED problems. Test results have indicated that the proposed method can obtain less expensive solutions than many other methods reported in the literature. Accordingly, the proposed CSA is a promising method for solving the practical nonconvex ED problems. ©The Institution of Engineering and Technology 2013.
Novgorodova O.,TU Dresden
Journal of Physics: Conference Series | Year: 2015
The ATLAS detector was designed and built to study proton-proton collisions produced at the LHC at centre-of-mass energies up to 14 TeV and instantaneous luminosities up to 1034 cm-2s-1. Liquid argon (LAr) sampling calorimeters are employed for electromagnetic and hadronic calorimetry. The luminosity for the proposed High Luminosity LHC phase (HL-LHC) will increase up to 5×1034 cm-2s-1 with the goal of accumulating an integrated luminosity of 3000 fb-1. This is well beyond the values for which the detectors were designed. The electromagnetic and hadronic calorimeters will be able to tolerate the increased particle flux, but the performance of the forward calorimeter (FCal) will be affected. Two possible solutions for keeping the current performance are being discussed. The readout electronics will also need to withstand larger radiation environment. In the hadronic endcap calorimeter (HEC) cold GaAs preamplifiers are located inside the endcap cryostats. The properties of these devices have been investigated in recent proton and neutron irradiation tests to determine whether they must be replaced. In addition, the entire front-end readout system is not expected to survive the integrated luminosity at the HL-LHC and will be replaced. The description of the new readout system is presented. © 2014 Published under licence by IOP Publishing Ltd.
Dunkel A.,TU Dresden
Landscape and Urban Planning | Year: 2015
Assessing information on aspects of identification, perception, emotion, and social interaction with respect to the environment is of particular importance to the fields of natural resource management. Our ability to visualize this type of information has rapidly improved with the proliferation of social media sites throughout the Internet in recent years. While many methods to extract information on human behavior from crowdsourced geodata already exist, this paper focuses on visualizing landscape perception for application to the fields of landscape and urban planning. Visualization of peoples' perceptual responses to landscape is demonstrated with crowdsourced photo geodata from Flickr, a popular photo sharing community. A basic, general method to map, visualize, and evaluate perception and perceptual values is proposed. The approach utilizes common tools for spatial knowledge discovery and builds on existing research, but is specifically designed for implementation within the context of landscape perception analysis and particularly suited as a base for further evaluation in multiple scenarios. To demonstrate the process in application, three novel types of visualizations are presented: the mapping of sightlines in Yosemite Valley, the assessment of landscape change in the area surrounding the High Line in Manhattan, and individual location analysis for Coit Tower in San Francisco. The results suggest that analyzing crowdsourced data may contribute to a more balanced assessment of the perceived landscape, which provides a basis for a better integration of public values into planning processes. © 2015 Elsevier B.V.
Robens T.,TU Dresden |
Stefaniak T.,University of California at Santa Cruz
European Physical Journal C | Year: 2015
We discuss the current status of theoretical and experimental constraints on the real Higgs singlet extension of the standard model. For the second neutral (non-standard) Higgs boson we consider the full mass range from (Formula Presented.) to (Formula Presented.) accessible at past and current collider experiments. We separately discuss three scenarios, namely, the case where the second Higgs boson is lighter than, approximately equal to, or heavier than the discovered Higgs state at around (Formula Presented.). We investigate the impact of constraints from perturbative unitarity, electroweak precision data with a special focus on higher-order contributions to the (Formula Presented.) boson mass, perturbativity of the couplings as well as vacuum stability. The latter two are tested up to a scale of (Formula Presented.) using renormalization group equations. Direct collider constraints from Higgs signal rate measurements at the LHC and (Formula Presented.) confidence level exclusion limits from Higgs searches at LEP, Tevatron, and LHC are included via the public codes HiggsSignals and HiggsBounds, respectively. We identify the strongest constraints in the different regions of parameter space. We comment on the collider phenomenology of the remaining viable parameter space and the prospects for a future discovery or exclusion at the LHC. © 2015, The Author(s).
Reschetilowski W.,TU Dresden
Russian Chemical Reviews | Year: 2013
Generally, methanol produced for chemical applications is made predominantly via fossil resources. But it can also be obtained from any carbon-containing feedstock, including biomass, biogas, forest residues, and municipal or other waste products. Perspective viewing and critical assessment show the possibilities and constraints of such alternative resources for the realization of the methanol economy with high sustainability. The bibliography includes 57 references. © 2013 Russian Academy of Sciences and Turpion Ltd.
Worch E.,TU Dresden
Journal of Water Supply: Research and Technology - AQUA | Year: 2010
Conventional adsorption models are not able to describe exactly the competitive adsorption of natural organic matter (NOM) and micropollutants during drinking water treatment with activated carbon. This problem is a consequence of the complex structure of natural organic matter. In the last years, two user-oriented model approaches, the tracer model (TRM) and the equivalent background compound model (EBCM), were proposed to overcome the difficulties in modelling the competitive adsorption in such multi-component systems. In this paper, these model approaches, as well as a simplified model for batch processes, are compared and opportunities and limitations are pointed out. The different aspects of model application are exemplarily discussed for the adsorption of two pesticides, atrazine and diuron, from Elbe River water onto activated carbon. As can be seen from the examples and from a series of studies, both models are suitable for modelling the micropollutant adsorption in the presence of NOM. The EBCM is somewhat easier to handle whereas the TRM allows for the consistent and parallel description of micropollutant and NOM adsorption. © 2010 IWA Publishing.
Droste M.,University of Leipzig |
Vogler H.,TU Dresden
Theoretical Computer Science | Year: 2012
We show that L-weighted automata, L-rational series, and L-valued monadic second order logic have the same expressive power, for any bounded lattice L and for finite and infinite words. We also prove that aperiodicity, star-freeness, and L-valued first-order and LTL-definability coincide. This extends classical results of Kleene, BchiElgotTrakhtenbrot, and others to arbitrary bounded lattices, without any distributivity assumption that is fundamental in the theory of weighted automata over semirings. In fact, we obtain these results for large classes of strong bimonoids which properly contain all bounded lattices. © 2011 Elsevier B.V. All rights reserved.
Ludwig-Muller J.,TU Dresden
Journal of Plant Physiology | Year: 2015
Plant diseases cause huge losses by changing the quality and quantity of harvested crops. Many disease symptoms caused by bacteria or fungi rely on the involvement of plant hormones, while other plant hormones act as defense signals in the plant. In this review the role of auxins in these processes will be evaluated. Some growth promoting plant hormones cause disease symptoms. For example auxins stimulate cell division and cell elongation in a healthy plant, but tumor formation after bacterial infection. Thus, control of auxin levels and auxin signaling pathways significantly contribute to the defense network in plants. Auxin can also act directly as defense molecule with antimicrobial activity. Since much research has been done in the recent years on auxin as a pathogenicity factor for many diseases, several examples will be presented to highlight the complexity between normal plant growth, which is regulated by auxin, and processes determining resistance or susceptibility, triggered by the same class of molecules. © 2014 Elsevier GmbH.
Hedrich C.M.,TU Dresden
Clinical Immunology | Year: 2016
Historically, autoimmune-inflammatory disorders were subdivided into autoinflammatory vs. autoimmune diseases. About a decade ago, an immunological continuum was proposed, placing "classical" autoinflammatory disorders, characterized by systemic inflammation in the absence of high-titer autoantibodies or autoreactive T lymphocytes, at the one end, and autoimmune disorders at the other end. We provide an overview of recent developments and observations, filling in some of the gaps and showing strong interconnections between innate and adaptive immune mechanisms, indicating that disorders from both ends of the immunological spectrum indeed share key pathomechanisms. We focus on three exemplary disorders: i) systemic juvenile idiopathic arthritis representing "classical" autoinflammatory disorders; ii) psoriasis, a mixed pattern disease; and iii) systemic lupus erythematosus, a prototypical autoimmune disease. We summarize scientific observations suggesting that, depending on disease stages and/or duration, individualized treatment targeting innate or adaptive immune mechanisms in disorders from either end of the immunological spectrum may control disease activity. © 2016 Elsevier Inc.
Kim D.H.,Yonsei University |
Kim W.T.,Cheongju University |
Park E.S.,Seoul National University |
Mattern N.,Leibniz Institute for Solid State and Materials Research |
And 2 more authors.
Progress in Materials Science | Year: 2013
Phase separation phenomena in metallic glass systems are reviewed. First, a brief introduction to the enhanced glass forming ability and the phase separation in metallic glass systems is given. Nano-scale phase separation observed in frozen-in glass is discussed in marginal glass formers such as Pd-, Fe, Al-base metallic glass systems as well as in bulk glass formers in Cu-, Zr- and Mg-base metallic glass systems. Since retention of glass forming ability is essential in phase separating glasses, thermodynamic and kinetic conditions for enhanced glass forming ability is introduced. Several thermodynamic aspects for decomposition by liquid-liquid phase separation which include stability conditions, decomposition in the multicomponent system, types of miscibility gap, calculation of bimodal and spinodal curves are introduced as a background for design of metallic glasses phase separating in the liquid state. The main mechanisms for phase separation are nucleation and growth mechanism and spinodal decomposition mechanism. The metallic glass systems which include an atom pair with large positive enthalpy of mixing decompose by liquid-liquid phase separation separate in the liquid state, forming two typical types of microstructure: droplet or interconnected type microstructures depending on the mechanism of phase separation. By calculation of the tile line, it is possible to design phase separating metallic glasses with high glass forming ability. Eventually, bulk-type phase separating metallic glasses with mm scale can be synthesized. Moreover, if there is a group of three atoms with large positive enthalpy of mixing in the liquid state in the multicomponent system, occurrence of three phase separation in the liquid state is possible. There are several parameters affecting the microstructure evolution during phase separation, which includes glass transition and critical temperatures, shape of bimodal and spinodal curves and quenching conditions. Phase separation in the solid state of the frozen-in glasses can give a clue on the phase separation prior to crystallization or direct nanocrystallization from the amorphous matrix. The amplitude of the composition fluctuation with a fixed wavelength can grow by heating in the solid state, if the spinodal decomposition. Finally, some advantages of phase separation phenomena in metallic glass systems are highlighted. © 2013 Elsevier Ltd. All rights reserved.
Zhang D.-B.,University of Minnesota |
Dumitrica T.,University of Minnesota |
Seifert G.,TU Dresden
Physical Review Letters | Year: 2010
Objective molecular dynamics combined with density-functional-based tight binding makes it possible to compute chiral nanotubes as axial-screw dislocations. This enables the surprising revelation of a large catalog of MoS2 nanotubes that lack the prescribed translational symmetry and exhibit chirality-dependent electronic band gaps and elastic constants. Helical symmetry is the natural property to rely on when studying quasi-one-dimensional nanomaterials formally derived or grown via screw dislocations. © 2010 The American Physical Society.
Singh R.P.,TU Dresden
Blood | Year: 2013
Hypoxia is a prominent feature in the maintenance of hematopoietic stem cell (HSC) quiescence and multipotency. Hypoxia-inducible factor (HIF) prolyl hydroxylase domain proteins (PHDs) serve as oxygen sensors and may therefore regulate this system. Here, we describe a mouse line with conditional loss of HIF prolyl hydroxylase 2 (PHD2) in very early hematopoietic precursors that results in self-renewal of multipotent progenitors under steady-state conditions in a HIF1α- and SMAD7-dependent manner. Competitive bone marrow (BM) transplantations show decreased peripheral and central chimerism of PHD2-deficient cells but not of the most primitive progenitors. Conversely, in whole BM transfer, PHD2-deficient HSCs replenish the entire hematopoietic system and display an enhanced self-renewal capacity reliant on HIF1α. Taken together, our results demonstrate that loss of PHD2 controls the maintenance of the HSC compartment under physiological conditions and causes the outcompetition of PHD2-deficient hematopoietic cells by their wild-type counterparts during stress while promoting the self-renewal of very early hematopoietic progenitors.
Reichmann H.,TU Dresden
Journal of Neural Transmission | Year: 2016
There are many guidelines available concerning the treatment of Parkinson’s disease. Most of these advocate treating young-onset patients with a dopamine agonist and older patients with levodopa. The rationale behind this recommendation has its origins in the side effects associated with each of these drug classes: whilst levodopa leads to dyskinesia, which may not be relevant for patients with a limited life-expectancy, dopamine agonists have a much longer plasma half life which probably leads to more continuous dopamine receptor stimulation and thus decreases the occurrence and severity of dyskinesia. However, the side effects associated with the use of dopamine agonists, such as sleepiness, orthostatic problems, hallucinations and impulse control disorders are a drawback. In this overview, the hypothesis will be put forward that perhaps such a strict distinction is no longer needed. A new idea may be the early combination of levodopa with a dopamine agonist which would provide good clinical efficacy and, because of the relatively low doses involved, would reduce the side effects associated with both substances. MAO-B inhibitors may be a good option for early treatment and especially for patients who experience first motor fluctuations. Similarly, and particularly if a wearing-off symptom is present, COMT inhibitors smoothen and prolong the action of levodopa. More invasive escalation therapy comes into play when patients reach the advanced stages with problems of insufficient motor control, such as bradykinesia, rigidity and resting tremor, combined with on-time dyskinesia. The use of all oral and invasive treatment has to be individualized to gain a good motor and non-motor control and especially a good quality of life. © 2015, Springer-Verlag Wien.
Bonifacio E.,TU Dresden |
Ziegler A.G.,TU Munich
Endocrinology and Metabolism Clinics of North America | Year: 2010
Type 1 diabetes (T1D) has the hallmark characteristics of autoimmunity superimposed on genetic susceptibility. Both genes (HLA) and immune markers (autoantibodies) have been validated as predictive markers of the subsequent development of the disease in higher-risk relatives and the lower-risk general population. Over the last three decades, using a combination of genes, immune, and metabolic markers, clinicians are now able to quantify an individual's disease risk from 1 in 100,000 to more than 1 in 2. This article reviews these biomarkers and T1D prediction strategies, and discusses potential implications of prediction and natural history for the pathogenesis of T1D. © 2010 Elsevier Inc.
Bakeer T.,TU Dresden
Structural Safety | Year: 2016
For the safety assessment of vertically loaded masonry walls, the Eurocode 6 considers a linear limit state function with only one basic parameter for the compressive strength of masonry. This assumption disregards the contribution of the uncertainty in other material parameters, like the elastic modulus, which is more important than the compressive strength in slender masonry walls. Furthermore, Eurocode 0 gives no clear advice on how to deal with the partial safety factors for non-linear problems in general.A reliability assessment has been carried out for the vertically loaded masonry walls, in order to clearly understand the contribution of the uncertainty of different material parameters on the evaluation of safety. The limit state function of the problem has been calculated using the transfer-matrix method. The full probabilistic approach has been applied using Monte Carlo simulations which helped to propose a new approach for the use of the partial safety factors in the non-linear analysis. © 2016 Elsevier Ltd.
Mechtcherine V.,TU Dresden
Construction and Building Materials | Year: 2013
In the last 30 years the construction industry branch having to do with the repair, protection and strengthening of concrete has experienced explosive growth. This has been driven by the need to reverse the deterioration of, damage to, and defects in concrete structures as well as by changes in building use and code requirements. Accordingly, there is great need to improve the materials and techniques used in repair and strengthening. This article focuses on novel high-performance fibre-reinforced cement based-composites (HPFRCCs) for strengthening and repair of buildings and infrastructure made of concrete and, in some cases, masonry. Two new types of such material, textile-reinforced concrete (TRC) and strain-hardening cement-based composites (SHCCs), are introduced, highlighting with particular care the benefits and challenges of using HPFRCCs. Specific compositions and production techniques of the composites are presented, followed by a discussion of their mechanical properties in respect of their use on the job. Some reference is made to approaches in considering the load-carrying capacity of the strengthening layers made of HPFRCCs. Furthermore, the transport properties through layers of cracked composites are described as the basis for estimating how well they can protect concrete and its steel reinforcement against ingressing fluids and gases, i.e., against their deterioration. Finally, a number of practical applications of TRC and SHCC are described in order to demonstrate their great potential in the field of rehabilitation of existing concrete structures. © 2012 Elsevier B.V. All rights reserved.
May C.A.,TU Dresden
Experimental Eye Research | Year: 2012
In the murine model of oxygen-induced retinopathy of prematurity, early treatment (right after oxygen exposure) with triamcinolone reduced neovascularization and subsequently endostatin presence. Late treatment (3 days after oxygen exposure) limited pathological vascular sprouting, not interfering with normal vascularization of the retina. The effects remained unilateral in the treated eyes. © 2012 Elsevier Ltd.
Karalunas S.L.,Oregon Health And Science University |
Geurts H.M.,University of Amsterdam |
Konrad K.,RWTH Aachen |
Konrad K.,Institute of Neuroscience and Medicine 3 Research Center |
And 2 more authors.
Journal of Child Psychology and Psychiatry and Allied Disciplines | Year: 2014
Background Intraindividual variability in reaction time (RT) has received extensive discussion as an indicator of cognitive performance, a putative intermediate phenotype of many clinical disorders, and a possible trans-diagnostic phenotype that may elucidate shared risk factors for mechanisms of psychiatric illnesses. Scope and Methodology Using the examples of attention deficit hyperactivity disorder (ADHD) and autism spectrum disorders (ASD), we discuss RT variability. We first present a new meta-analysis of RT variability in ASD with and without comorbid ADHD. We then discuss potential mechanisms that may account for RT variability and statistical models that disentangle the cognitive processes affecting RTs. We then report a second meta-analysis comparing ADHD and non-ADHD children on diffusion model parameters. We consider how findings inform the search for neural correlates of RT variability. Findings Results suggest that RT variability is increased in ASD only when children with comorbid ADHD are included in the sample. Furthermore, RT variability in ADHD is explained by moderate to large increases (d = 0.63-0.99) in the ex-Gaussian parameter τ and the diffusion parameter drift rate, as well as by smaller differences (d = 0.32) in the diffusion parameter of nondecision time. The former may suggest problems in state regulation or arousal and difficulty detecting signal from noise, whereas the latter may reflect contributions from deficits in motor organization or output. The neuroimaging literature converges with this multicomponent interpretation and also highlights the role of top-down control circuits. Conclusion We underscore the importance of considering the interactions between top-down control, state regulation (e.g. arousal), and motor preparation when interpreting RT variability and conclude that decomposition of the RT signal provides superior interpretive power and suggests mechanisms convergent with those implicated using other cognitive paradigms. We conclude with specific recommendations for the field for next steps in the study of RT variability in neurodevelopmental disorders. © 2014 The Authors. Journal of Child Psychology and Psychiatry. © 2014 Association for Child and Adolescent Mental Health.
Strunk A.,TU Dresden
Proceedings - 8th IEEE European Conference on Web Services, ECOWS 2010 | Year: 2010
Service compositions build new services by orchestrating a set of existing services. In the Internet of Services there may be many functional similar services, but with different Quality of Service (QoS). Thus a significant research problem in service compositions is how to select the composition's composite services that the overall QoS of the composition is being maximized. This paper summarizes, classifies and evaluates major research efforts in this area and gives an overview about further open research questions. © 2010 IEEE.
Dreisbach G.,University of Regensburg |
Fischer R.,TU Dresden
Frontiers in Human Neuroscience | Year: 2012
Adapting to changing task demands is one of the hallmarks of human cognition. According to an influential theory, the conflict monitoring theory, the adaptation of information processing occurs in a context-sensitive manner in that conflicts signal the need for control recruitment. Starting from the conflict monitoring theory, here the authors discuss the role of affect in the context of conflict-triggered processing adjustments from three different perspectives: (1) the affective value of conflict per se, (2) the affective modulation of conflict-triggered processing adjustments, and (3) the modulation of conflict adaptation by reward. Based on the current empirical evidence, the authors stress the importance of disentangling effects of affect and reward on conflict-triggered control adjustments. © 2012 Dreisbach and Fischer.
Schoor C.,TU Dresden |
Bannert M.,University of Wurzburg
Computers in Human Behavior | Year: 2012
The purpose of this study was to explore sequences of social regulatory processes during a computer-supported collaborative learning task and their relationship to group performance. Analogous to self-regulation during individual learning, we conceptualized social regulation both as individual and as collaborative activities of analyzing, planning, monitoring and evaluating cognitive and motivational aspects during collaborative learning. We analyzed the data of 42 participants working together in dyads. They had 90 min to develop a common handout on a statistical topic while communicating only via chat and common editor. The log files of chat and editor were coded regarding activities of social regulation. Results show that participants in dyads with higher group performance (N = 20) did not differ from participants with lower group performance (N = 22) in the frequencies of regulatory activities. In an exploratory way, we used process mining to identify process patterns for high versus low group performance dyads. The resulting models show clear parallels between high and low achieving dyads in a double loop of working on the task, monitoring, and coordinating. Moreover, there are no major differences in the process of high versus low achieving dyads. Both results are discussed with regard to theoretical and empirical issues. Furthermore, the method of process mining is discussed. © 2012 Elsevier Ltd. All rights reserved.
Hermsdorf D.,TU Dresden
Radiation Measurements | Year: 2012
The sensitivity of charged particle registration with SSNTD is the most important parameter to decide about the applicability of those detectors in research, technology and environmental dosimetry. The sensitivity is strongly influenced by the treatment of detector samples before, during and after the exposure and the final evaluation process by chemical etching. Whereas changes in detection properties by external environmental influences are generally considered, the dependences on the etching conditions are ignored. Commonly the sensitivity is assumed to compensate variations in the etching conditions for track revealing. In the present work the validity of this hypothesis will be checked. In the frame of the existing database the sensitivity is not really independent on variations in etching temperatures and should be corrected for differences in the activation energies for stimulation of the bulk and track etching process. Differences in the concentration dependence may be of minor importance. Furthermore, the registration sensitivity depends on environmental conditions before, during and after the irradiation with particles under investigation. Such external parameters are the air pressure, the sample temperature and modification of bulk material by out-gassing in vacuum and exposure to γ-rays. However, the available database is insufficient and inaccurate to draw final conclusions on the detection properties of SSNTD under various external and internal conditions. © 2012 Elsevier Ltd. All rights reserved.
Muller P.,TU Dresden |
Schwille P.,Max Planck Institute of Biochemistry |
Weidemann T.,Max Planck Institute of Biochemistry
Bioinformatics | Year: 2014
Summary: We present a graphical user interface (PyCorrFit) for the fitting of theoretical model functions to experimental data obtained by fluorescence correlation spectroscopy (FCS). The program supports many data file formats and features a set of tools specialized in FCS data evaluation. Availability and implementation: The Python source code is freely available for download from the PyCorrFit web page at http://pycorrfit. craban.de. We offer binaries for Ubuntu Linux, Mac OS X and Microsoft Windows. © The Author 2014. Published by Oxford University Press.
Hackl A.,California Institute of Technology |
Vojta M.,TU Dresden
Physical Review Letters | Year: 2011
The heavy-fermion metal YbRh2Si2 displays a field-driven quantum phase transition where signatures of a Fermi-surface reconstruction have been identified, often interpreted as a breakdown of the Kondo effect. We argue that instead many properties of the material can be consistently described by assuming a Zeeman-driven Lifshitz transition of narrow heavy-fermion bands. Using a suitable quasiparticle model, we find a smeared jump in the Hall constant and lines of maxima in susceptibility and specific heat, very similar to experimental data. An intermediate non-Fermi-liquid regime emerges due to the small effective Fermi energy near the transition. Further experiments to discriminate the different scenarios are proposed. © 2011 American Physical Society.
Wolf S.,TU Dresden |
Hewitt J.,Institute of Environmental Science and Research Ltd |
Greening G.E.,Institute of Environmental Science and Research Ltd
Applied and Environmental Microbiology | Year: 2010
Human and animal fecal pollution of the environment presents a risk to human health because of the presence of pathogenic viruses and bacteria. To distinguish between human and animal sources of pollution, vre designed specific real-time reverse transcription (RT)-PCR assays for human and animal enteric viruses, including norovirus genogroups I, II, and III; porcine adenovirus types 3 and S; ovine adenovirus; atadenovirus; and human adenovirus species C and F, which are excreted by Infected humans, pigs, cattle, sheep, deer, and goats, and for the detection of F+ RNA bacteriophage genogroups I to IV, which are associated with human and animal wastes. The sensitivity of this viral toolbox (VTB) was tested against 10-fold dilution series of DNA plasmids that carry the target sequences of the respective viruses and was shown to detect at least 10 plasmid copies for each assay. A panel of human and animal enteric and respiratory viruses showed these assays to be highly sensitive and specific to their respective targets. The VTB was used to detect viruses in fecal and environmental samples, including raw sewage and biosolids from municipal sewage treatment plants, abattoir sewage, and fecally contaminated shellfish and river water, which were likely to contain animal or human viruses. Copyright © 2010, American Society for Microbiology. All Rights Reserved.
Korten T.,Max Planck Institute of Molecular Cell Biology and Genetics |
Birnbaum W.,University of Paderborn |
Kuckling D.,University of Paderborn |
Diez S.,Max Planck Institute of Molecular Cell Biology and Genetics |
Diez S.,TU Dresden
Nano Letters | Year: 2012
First lab-on-chip devices based on active transport by biomolecular motors have been demonstrated for basic detection and sorting applications. However, to fully employ the advantages of such hybrid nanotechnology, versatile spatial and temporal control mechanisms are required. Using a thermo-responsive polymer, we demonstrate the selective starting and stopping of modified microtubules gliding on a kinesin-1-coated surface. This approach allows the self-organized separation of multiple microtubule populations and their respective cargoes. © 2011 American Chemical Society.
Huang X.,Leibniz Institute of Polymer Research |
Huang X.,University of Bristol |
Voit B.,Leibniz Institute of Polymer Research |
Voit B.,TU Dresden
Polymer Chemistry | Year: 2013
Recently, the construction of multi-compartment polymeric capsules has received considerable attention; for the development of next generation hollow structure carriers, multi-compartmentalization is a key requirement. In this review we give a brief overview with regard to the different preparation methods of multi-compartment polymeric capsules including self-assembly, surface-initiated polymerization, layer-by-layer assembly, emulsion-based methods, in addition to self-assembly approaches using dendrimers or hyperbranched polymers as construction units. Finally, a short summary on potential biological applications is given. © 2013 The Royal Society of Chemistry.
Heinzig A.,NaMLab gGmbH |
Slesazeck S.,NaMLab gGmbH |
Kreupl F.,TU Munich |
Mikolajick T.,NaMLab gGmbH |
And 2 more authors.
Nano Letters | Year: 2012
Over the past 30 years electronic applications have been dominated by complementary metal oxide semiconductor (CMOS) devices. These combine p- and n-type field effect transistors (FETs) to reduce static power consumption. However, CMOS transistors are limited to static electrical functions, i.e., electrical characteristics that cannot be changed. Here we present the concept and a demonstrator of a universal transistor that can be reversely configured as p-FET or n-FET simply by the application of an electric signal. This concept is enabled by employing an axial nanowire heterostructure (metal/intrinsic- silicon/metal) with independent gating of the Schottky junctions. In contrast to conventional FETs, charge carrier polarity and concentration are determined by selective and sensitive control of charge carrier injections at each Schottky junction, explicitly avoiding the use of dopants as shown by measurements and calculations. Besides the additional functionality, the fabricated nanoscale devices exhibit enhanced electrical characteristics, e.g., record on/off ratio of up to 1 ×10 9 for Schottky transistors. This novel nanotransistor technology makes way for a simple and compact hardware platform that can be flexibly reconfigured during operation to perform different logic computations yielding unprecedented circuit design flexibility. © 2011 American Chemical Society.
Georgiev M.I.,Bulgarian Academy of Science |
Georgiev M.I.,Leiden University |
Agostini E.,National University of Rio Cuarto |
Ludwig-Muller J.,TU Dresden |
Xu J.,Arkansas State University
Trends in Biotechnology | Year: 2012
Hairy root syndrome is a disease that is induced by Agrobacterium rhizogenes infection and characterized by a proliferation of excessively branching roots. However, in the past 30 years A. rhizogenes-mediated transformation has also provided a valuable platform for studying biosynthesis pathways in plants. Furthermore, the genetically transformed root cultures are becoming increasingly attractive, cost-effective options for mass-producing desired plant metabolites and expressing foreign proteins. Numerous proof-of-concept studies have demonstrated the feasibility of scaling up hairy-root-based processes while maintaining their biosynthetic potential. Recently, hairy roots have also shown immense potential for applications in phytoremediation, that is, plant-based decontamination of polluted environments. This review highlights recent progress and limitations in the field, and outlines future perspectives for the industrial exploitation of hairy roots. © 2012 Elsevier Ltd.
Anatomy of the pectoral and forelimb muscles of wildtype and green fluorescent protein-transgenic axolotls and comparison with other tetrapods including humans: A basis for regenerative, evolutionary and developmental studies
Diogo R.,Howard University |
Tanaka E.M.,TU Dresden
Journal of Anatomy | Year: 2012
The axolotl Ambystoma mexicanum is one of the most used model organisms in evolutionary, developmental and regenerative studies, particularly because it can reconstitute a fully functional and complete forelimb/hindlimb. Surprisingly, there is no publication that describes all the pectoral and forelimb muscles of this species or provides a comparative framework between these muscles and those of other model organisms and of modern humans. In the present paper we describe and illustrate all these muscles in A. mexicanum and provide the first report about the myology of adults of a model organism that is based on analyses and dissections of both wildtype animals and transgenic animals that express green fluorescent protein (GFP) in muscle fibers. On the one hand, the inclusion of GFP-transgenic animals allows us to show the muscles as more commonly seen, and thus easier to understand, by current developmental and regenerative biologists. On the other hand, by including wildtype and GFP-transgenic animals and by visualizing these latter animals with and without a simultaneous transmission laser light, we were able to obtain a more complete and clearer understanding of the exact limit of the fleshy and tendinous parts of the muscles and their specific connections with the skeletal elements. This in turn allowed us to settle some controversies in previous anatomical and comparative studies. As most developmental, regenerative and evolutionary biologists are interested in comparing their observations of A. mexicanum with observations in other model organisms, and ultimately in using this information to increase the understanding of human evolution and medicine, we also provide tables showing the homologies between the pectoral and forelimb muscles of axolotls, of model organisms such as mice, frogs and chicken, and of Homo sapiens. An example illustrating the outcomes of using our methodology and of our observations is that they revealed that, contrary to what is often stated in the literature, A. mexicanum has a muscle coracoradialis that has both a well developed proximal fleshy belly and a distal long and thin tendon, supporting the idea that this muscle very likely corresponds to at least part of the amniote biceps brachii. Our observations also: (i) confirmed that the flexores digitorum minimi, interphalangeus digiti 3, pronator quadratus and palmaris profundus 1 are present as distinct muscles in A. mexicanum, supporting the idea that the latter muscle does not correspond to the pronator accessorius of reptiles; (ii) confirmed that the so-called extensor antebrachii radialis is present as a distinct muscle in this species and, importantly, indicated that this muscle corresponds to the supinator of other tetrapods; (iii) showed that, contrary to some other urodeles, including some other Ambystoma species, there is no distinct muscle epitrochleoanconeus in A. mexicanum and; (iv) showed that the ulnar and radial bundles of the abductor et extensor digiti 1 correspond to the abductor pollicis longus and extensor pollicis longus of other tetrapods, respectively. © 2012 The Authors. Journal of Anatomy © 2012 Anatomical Society.
Schmitt J.,TU Dresden
Hautarzt | Year: 2011
Within the past years, health services research projects have analyzed critically the management of atopic eczema (AE) in routine care, quantified the utility of controlling severe AE, and introduced an international standardization of core outcome measures for AE. With a prevalence of 16%, AE is the most frequent chronic condition at all among children and adolescents seeking medical care. Despite lower prevalence in adults, about 60% of patients with AE in routine care are adults. There is a clinically relevant comorbidity of AE and psychiatric conditions. Independent of patient's age and physician's medical discipline topical corticosteroids dominate outpatient treatment of AE. However, there is considerable heterogeneity in the management of AE between treating physicians. Despite a lack of clinical trials, systemic corticosteroids are most frequently prescribed for severe AE. In contrast, cyclosporine only plays a minor role in routine care of severe AE although its efficacy is well-documented in trials. This observation stimulated a head-to-head trial that indicated superiority of cyclosporine over prednisolone for severe adult AE. The control of severe AE has high priority from the perspective of the general population and from the patients' perspective. Competence of the treating physician, disease severity and patient's competence to adjust treatment to disease activity are the main determinants of patient satisfaction. Aiming for a better comparability of clinical trials and better translation of trial evidence into clinical practice, we conducted a Delphi exercise including clinical experts from 11 countries, editors of international dermatological journals, regulatory agencies, and patient representatives. The preliminary core set of outcome domains for eczema trials as defined by the panel included symptoms, physician-assessed clinical signs, and a measurement for long-term control of flares. Symptoms such as itching should be regularly assessed in clinical practice. The presented studies indicate that health services research not only describes and critically analyzes the effectiveness of routine clinical care, but is also translational research in that it may stimulate clinical trials and generate new, clinically relevant hypotheses for experimental studies. © 2011 Springer-Verlag.
Ansorge-Schumacher M.B.,TU Dresden |
Thum O.,Evonik Industries
Chemical Society Reviews | Year: 2013
Commercial products for personal care, generally perceived as cosmetics, have an important impact on everyday life worldwide. Accordingly, the market for both consumer products and specialty chemicals comprising their ingredients is considerable. Lipases have started to play a minor role as active ingredients in so-called 'functional cosmetics' as well as a major role as catalysts for the industrial production of various specialty esters, aroma compounds and active agents. Interestingly, both applications almost always require preparation by appropriate immobilisation techniques. In addition, for catalytic use special reactor concepts often have to be employed due to the mostly limited stability of these preparations. Nevertheless, these processes show distinct advantages based on process simplification, product quality and environmental footprint and are therefore apt to more and more replace traditional chemical processes. Here, for the first time a review on the various aspects of using immobilised lipases in the cosmetics industry is given. © 2013 The Royal Society of Chemistry.
Bschor T.,Schlosspark Clinic |
Bschor T.,TU Dresden
Expert Review of Neurotherapeutics | Year: 2010
Therapy-resistant depression is not untreatable. Numerous treatment methods with substantiated effectiveness exist. However, none of them are able to ensure remission. Thus, what matters when treating therapy-resistant depression is the strict, step-by-step deployment of existing therapeutic options at the right tempo and with a regular systematic evaluation of patient response. Remission should always be the aim, not just some abatement in symptoms (response). The following should be avoided: too small dosages of medication; changing the therapeutic strategy too frequently or too quickly; thoughtlessly sticking to an ineffective treatment over too long a period of time; or unsystematic poly-pharmacy. If these are all avoided than therapy-resistant depressive patients will have a good chance of recovery. © 2010 Expert Reviews Ltd.
Kroneberg C.,University of Mannheim |
Heintze I.,Coordination of Social Planning |
Mehlkop G.,TU Dresden
Criminology | Year: 2010
Rational choice theories (RCTs) of crime assume actors behave in an instrumental, outcome-oriented way. Accordingly, individuals should weight the costs and benefits of criminal acts with subjective probabilities that these outcomes will occur. Previous studies either do not directly test this central hypothesis or else yield inconsistent results. We show that a meaningful test can be conducted only if a broader view is adopted that takes into account the interplay of moral norms and instrumental incentives. Such a view can be derived from the Model of Frame Selection (Kroneberg, 2005) and the Situational Action Theory of Crime Causation (Wikström, 2004). Based on these theories, we analyze the willingness to engage in shoplifting and tax fraud in a sample of 2,130 adults from Dresden, Germany. In line with our theoretical expectations, we find that only respondents who do not feel bound by moral norms show the kind of instrumental rationality assumed in RCTs of crime. Where norms have been strongly internalized, and in the absence of neutralizations, instrumental incentives are irrelevant. © 2010 American Society of Criminology.
Soetaert K.,Netherlands Institute of Ecology |
Petzoldt T.,TU Dresden
Journal of Statistical Software | Year: 2010
Mathematical simulation models are commonly applied to analyze experimental or environmental data and eventually to acquire predictive capabilities. Typically these models depend on poorly defined, unmeasurable parameters that need to be given a value. Fitting a model to data, so-called inverse modelling, is often the sole way of finding reasonable values for these parameters. There are many challenges involved in inverse model applications, e.g., the existence of non-identifiable parameters, the estimation of parameter uncertainties and the quantification of the implications of these uncertainties on model predictions. The R package FME is a modeling package designed to confront a mathematical model with data. It includes algorithms for sensitivity and Monte Carlo analysis, parameter identifiability, model fitting and provides a Markov-chain based method to estimate parameter confidence intervals. Although its main focus is on mathematical systems that consist of differential equations, FME can deal with other types of models. In this paper, FME is applied to a model describing the dynamics of the HIV virus.
Stange D.E.,TU Dresden
Digestive Diseases | Year: 2013
The intestine has become a prime model system to study stem cell biology. Intestinal stem cells can be identified based on the expression of a unique marker gene, namely Lgr5. A transgenic mouse model expressing green fluorescent protein in intestinal stem cells has allowed their visualization, isolation, molecular characterization and use in generating organoids: small mini-guts that contain all cell types of the intestine. Detailing the behavior of intestinal stem cells has also led to new insights concerning the mechanism of self-renewal versus differentiation. Genes and pathways directing daughter cells of stem cells towards the differentiated lineages of the intestine are getting better defined. Of all differentiated cells, Paneth cells play a distinguished role: they emerged from pure bystanders to the guardians of the stem cell. Taken together, a detailed molecular picture emerges that describes the mechanisms of intestinal homeostatic self-renewal and outlines new therapeutic avenues. © 2013 S. Karger AG, Basel.
Hoyer B.,TU Dresden
Biomacromolecules | Year: 2012
Biomimetic mineralization of collagen is an advantageous method to obtain resorbable collagen/hydroxy-apatite composites for application in bone regeneration. In this report, established procedures for mineralization of bovine collagen were adapted to a new promising source of collagen from salmon skin challenged by the low denaturation temperature. Therefore, in the first instance, variation of temperature, collagen concentration, and ionic strength was performed to reveal optimized parameters for fibrillation and simultaneous mineralization of salmon collagen. Porous scaffolds from mineralized salmon collagen were prepared by controlled freeze-drying and chemical cross-linking. FT-IR analysis demonstrated the mineral phase formed during the preparation process to be hydroxyapatite. The scaffolds exhibited interconnecting porosity, were sufficiently stable under cyclic compression, and showed elastic mechanical properties. Human mesenchymal stem cells were able to adhere to the scaffolds, cell number increased during cultivation, and osteogenic differentiation was demonstrated in terms of alkaline phosphatase activity.
Franceschini A.,Swiss Institute of Bioinformatics |
Szklarczyk D.,Novo Nordisk AS |
Frankild S.,Novo Nordisk AS |
Kuhn M.,TU Dresden |
And 8 more authors.
Nucleic Acids Research | Year: 2013
Complete knowledge of all direct and indirect interactions between proteins in a given cell would represent an important milestone towards a comprehensive description of cellular mechanisms and functions. Although this goal is still elusive, considerable progress has been made - particularly for certain model organisms and functional systems. Currently, protein interactions and associations are annotated at various levels of detail in online resources, ranging from raw data repositories to highly formalized pathway databases. For many applications, a global view of all the available interaction data is desirable, including lower-quality data and/or computational predictions. The STRING database (http://string-db.org/) aims to provide such a global perspective for as many organisms as feasible. Known and predicted associations are scored and integrated, resulting in comprehensive protein networks covering >1100 organisms. Here, we describe the update to version 9.1 of STRING, introducing several improvements: (i) we extend the automated mining of scientific texts for interaction information, to now also include full-text articles; (ii) we entirely re-designed the algorithm for transferring interactions from one model organism to the other; and (iii) we provide users with statistical information on any functional enrichment observed in their networks. © The Author(s) 2012.
Michler H.,TU Dresden
Beton- und Stahlbetonbau | Year: 2013
On account of its very good mechanical properties textile reinforced concrete (TRC) is a material to be best to do lightweight concrete constructions. With this material it is possible to realize prefabricated concrete bridges with a size that was not possible yet due to limits in transport. Shorter construction or traffic blockages times are also a positive effect and with this economic and qualitative advantages are achievable due to prefabrication. A praxis test was done with a bridge prefabricated in Oschatz/ Saxony and transported to Kempten/Allgäu for mounting. The Rottach-Bridge does prove and demonstrate that textile reinforced concrete constructions can also assert themselves economically in the market. The bridge was put into operation in autumn 2007 and now has proved itself already in sixth winter. This is taken as an occasion to report in this paper on the design, calculation and preparation of textile concrete bridge Kempten. This report is based on and takes over parts from this. Copyright © 2013 Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin.
Franze K.,University of Cambridge |
Janmey P.A.,University of Pennsylvania |
Guck J.,University of Cambridge |
Guck J.,TU Dresden
Annual Review of Biomedical Engineering | Year: 2013
Biological cells are well known to respond to a multitude of chemical signals. In the nervous system, chemical signaling has been shown to be crucially involved in development, normal functioning, and disorders of neurons and glial cells. However, there are an increasing number of studies showing that these cells also respond to mechanical cues. Here, we summarize current knowledge about the mechanical properties of nervous tissue and its building blocks, review recent progress in methodology and understanding of cellular mechanosensitivity in the nervous system, and provide an outlook on the implications of neuromechanics for future developments in biomedical engineering to aid overcoming some of the most devastating and currently incurable CNS pathologies such as spinal cord injuries and multiple sclerosis. Copyright © 2013 by Annual Reviews.
Haroske G.,TU Dresden
Current Opinion in Rheumatology | Year: 2011
Purpose of review: To describe current progress in understanding pyoderma gangraenosum, illustrate clinical observations and discuss therapeutic interventions. Recent findings: The proline-rich, glutamic acid-rich, serine-rich and threonine-rich (PEST) family of protein tyrosine phosphatases is a critical regulator of adhesion and migration. PSTPIP1 is a cytoskeleton-associated adaptor protein that links PEST-type phosphatases to their substrates. This pathway seems to be involved in diseases related to pyoderma gangraenosum such as chronic inflammatory bowel disease and aseptic abscesses syndrome. Pyoderma gangraenosum is one of the most common extra-intestinal manifestations of chronic inflammatory bowel disease. In multivariate analyses, pyoderma gangraenosum was significantly and independently associated with black African origin, familial history of ulcerative colitis, uninterrupted pancolitis as the initial location of inflammatory bowel disease, permanent stoma, eye involvement and erythema nodosum. The treatment of choice for idiopathic pyoderma gangraenosum is systemic corticosteroids but cyclosporine A, mycophenolate mofetil and tumour necrosis factor-alpha inhibitors have been successful to control pyoderma gangraenosum as second line or adjuvant options. In addition, small studies have been published with successful therapeutic intervention using alefacept, visilizumab or anakinra but controlled trials are warranted. Although systemic immunosuppressants remain the choice therapy for most cases of pyoderma gangraenosum, a local approach should be considered in localized disease. Recently, topical tacrolimus has successfully been used as an off-label drug in localized disease. Summary: By a better understanding of the underlying pathology and recent drug developments patients with pyoderma gangraenosum will benefit. For several new drugs, however, controlled trials are warranted. © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins.
Altinsoy M.E.,TU Dresden
International Journal of Vehicle Noise and Vibration | Year: 2013
The aims of this study are the generation and comparison of the semantic spaces of vehicle idling sounds and vibrations and the determination of their quality dimensions. In this study, two different sets of quality attributes were developed for idling sounds (34 attributes) and whole-body vibrations (22 attributes). In contrast to prior investigations, the results demonstrated that the sound level alone is an insufficient attribute for describing the complexity of idle sounds and vibration perceptions. The qualities of both idle sounds and idle vibrations have multidimensional, complex characters. The results show that intensity-dependent attributes, signal-based attributes in terms of spectrum and temporal properties, and comfort- and emotion-based attributes are all required to characterise the idling noise, vibration, and harshness (NVH) performance of vehicles. Therefore, an index was proposed based on psychoacoustic metrics such as loudness, sharpness, roughness, fluctuation strength, and relative approach. The results also show that emotional aspects play an important role for the assessment of sound and vibrations. Copyright © 2013 Inderscience Enterprises Ltd.
May C.A.,TU Dresden
European journal of histochemistry : EJH | Year: 2013
Although Merkel cell carcinoma of the eye lid is reported frequently in the literature, only limited information exists about the distribution of Merkel cells in this tissue. Therefore, serial sections of 18 human cadaver eye lids (donors ages ranging between 63 and 97 years) were stained for cytokeratin 20 in various planes. The overall appearance of Merkel cells in these samples was low and mainly located in the outer root layer of the cilia hair follicles. Merkel cells were more frequent in the middle, and almost not detectable at the nasal and temporal edges. The localization is in accordance with that of Merkel cell carcinoma, but concerning the scarce appearance within this adulthood group, a specific physiological role of these cells in the eye lid is difficult to establish.
Mustin B.,TU Dresden |
Stoeber B.,University of British Columbia
Microfluidics and Nanofluidics | Year: 2010
Polymer microspheres can deposit successively in microfluidic channels until they block a flow passage, which then leads to device failure. This article presents investigations of the effect of particle size distribution on the dynamics of channel blockage in microfluidic systems. The presented measurements and observations show that a low concentration of relatively large particles in a suspension has a major effect on the average time for a microchannel to be blocked by particles. Depending on the size distribution of particles in a suspension microchannel blockage occurs through successive particle deposition, particle size exclusion, or through a combination of these effects. © Springer-Verlag 2010.
Lopez-Val D.,Catholic University of Louvain |
Robens T.,TU Dresden
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2014
The link between the electroweak gauge boson masses and the Fermi constant via the muon lifetime measurement is instrumental for constraining and eventually pinning down new physics. We consider the simplest extension of the standard model with an additional real scalar SU(2)L - U(1)Y singlet and compute the electroweak precision parameter Δr, along with the corresponding theoretical prediction for the W-boson mass. When confronted with the experimental W-boson mass measurement, our predictions impose limits on the singlet model parameter space. We identify regions, especially in the mass range which is accessible by the LHC, where these correspond to the most stringent experimental constraints that are currently available. © 2014 American Physical Society.
Schaller J.,TU Dresden |
Struyf E.,University of Antwerp
Hydrobiologia | Year: 2013
The decomposition rate of plant litter is important for the carbon cycle. Element stoichiometry and hardly degradable carbon compounds are main factors controlling the decomposition rate of plant litter. Recent research has linked these factors to silicon availability during plant growth, but no research focused on the effect of silicon on litter decomposition. We therefore conducted a batch experiment to assess the effect of silicon availability to plants on litter degradation, nutrient release and multi elemental stoichiometry. Experiments were conducted in the presence or absence of invertebrate shredders (Gammaruspulex). We show that nutrient content (affected by silicon availability during plant growth) has a strong impact on nutrient turnover, while DOC, N, and Mn were mainly controlled by invertebrate feeding. The carbon turnover during microbial litter decay was strongly influenced by the silicon availability during plant growth, with quicker potential C turnover of litter with higher silicon content. In both Si-rich and Si-poor litter, feeding by invertebrate shredders positively impacted turnover rates, but effects were less pronounced in Si-rich litter. It can be concluded that silicon availability in wetlands dominated by reed plays an important role in carbon sequestration, nutrient cycling, and remobilization during aquatic litter decay. © 2013 Springer Science+Business Media Dordrecht.
Coordes R.,TU Dresden
European Journal of Forest Research | Year: 2013
When forest stands are established by planting, the initial density is often chosen based on recommendations of specific plant numbers. Since forest owners typically face different alternatives for the employment of their opportunities and since market situations often change more rapidly and on a smaller scale than the characteristics of forest sites, the question arises whether these factors are reflected in one or within a small range of planting densities. Even though some advised densities might be profitable for some forest owners and market situations, the shift of profitable timber production as a result of changes in the circumstances surrounding the investment is unclear. In this paper, the influence of the planting density on the profitable production of timber is analysed with the explicit inclusion of price differentials as these offer incentives for the choice of the planting density in Central Europe. Since numerical calculations based on empirical data are required for an analysis of the complex facets of price differentials, the specific statements are restricted to the tree species Norway spruce (Picea abies Karst.). By means of typical calculation examples, the effects of changes in investment parameters are exemplified and discussed against the background of a sensitivity analysis. The results reveal the boundaries for the profitable production of high-quality timber and show that forest owners might compensate changes in the investment situation by adjustments of either or both the rotation age and the planting density. © 2013 Springer-Verlag Berlin Heidelberg.
Taubenberger A.V.,TU Dresden |
Taubenberger A.V.,Queensland University of Technology
Advanced Drug Delivery Reviews | Year: 2014
Bone metastasis occurs frequently in patients with advanced breast cancer and is a major cause of morbidity and mortality in these patients. In order to advance current therapies, the mechanisms leading to the formation of bone metastases and their pathophysiology have to be better understood. Several in vitro models have been developed for systematic studies of interactions between breast cancer cells and the bone microenvironment. Such models can provide insights into the molecular basis of bone metastatic colonisation and also may provide a useful platform to design more physiologically relevant drug testing assays. This review describes different in vitro approaches and discusses their advantages and disadvantages. © 2014 Elsevier B.V.
Luo C.,Leibniz Institute of Polymer Research |
Sommer J.-U.,Leibniz Institute of Polymer Research |
Sommer J.-U.,TU Dresden
Physical Review Letters | Year: 2014
Polymer chains form lamellar structures during crystallization which display a memory of thermal history. Using molecular dynamics simulations and primitive path analysis, we show a direct dependence of both density and crystalline stem length on the local entanglement length. The slow relaxation of the entanglement state after a change of external conditions can directly explain the role of thermal history for polymer crystallization, in particular memory effects. The analysis of the local entanglement state can be used to predict the occurrence of nucleation events. Our results present a fresh insight of the nonequilibrium properties of polymer crystals which might be identified as "frozen topology" of polymer melts. © 2014 American Physical Society.
Fink K.,TU Berlin |
Bernet S.,TU Dresden
IEEE Transactions on Power Electronics | Year: 2013
This paper describes the design and the experimental investigation of a gate drive unit with closed-loop control of the collector current slope diC/dt for multichip insulated-gate bipolar transistors (IGBTs). Compared to a pure resistive gate drive, the proposed diC/dt control offers the ability to adjust the collector current slope freely which helps to find an optimized relation between switching losses and secure operation of the freewheeling diode for every type of IGBT. Based on the description of IGBTs switching behavior, the design and the realization of the gate drive are presented. The test setup and the comparison of switching tests with and without the proposed diC/dt control are discussed. © 1986-2012 IEEE.
Distler M.,TU Dresden
Der Pathologe | Year: 2012
Ductal adenocarcinoma is the most frequent malignant tumor of the pancreas and total resection of the pancreatic tumor is still the only curative treatment option. Most tumors are located in the pancreatic head, therefore, pylorus-preserving pancreaticoduodenectomy (Whipple PPPD) is the oncological standard procedure. By concentrating pancreatic resections in specialized centers for pancreatic surgery perioperative mortality and morbidity has decreased in recent years. However, pancreatic resections remain complex and difficult operations and pancreatic anastomosis is particular challenging. To achieve complete resection (R0) resection and reconstruction of large venous vessels is often necessary. Resection of arterial vessels is rarely performed and usually does not lead to an R0 resection of the tumor. Currently adjuvant chemotherapy after total tumor resection is standard of care for all tumor stages but neoadjuvant regimes have recently been reported increasingly more often. Advances in translational research has led to a better understanding of tumor biology and new diagnostic options and therapies are expected in the near future.
Bakeer T.,TU Dresden
Engineering Structures | Year: 2016
Masonry walls are very sensitive to flexural effects due to low tensile strength which, in turn, greatly influences the load bearing capacity under compression. The main source of flexural effects may results from the eccentric loading at the ends of the wall or from any lateral loading like the wind action, the earth pressure, or the second order effect of the applied actions. Several analytical solutions were proposed in literature to solve the differential equation of the problem, but those solutions were limited to special conditions. In the current contribution, a general formulation for the non-linear stability problem has been formulated numerically based on the transfer-matrix method. Despite the method is out of professional use today and don't possess the potential and flexibility of the finite elements but for the current addressed problem, it is still the most efficient.A relative form description has been introduced to formulate the stability theory of masonry walls. This description has been used to minimize the dimensions of matrixes in the transfer-matrix method and to produce the equations in a compact form. The algorithms of the method have been derived for general boundary and loading conditions with a user-defined non-linear material model. Algorithms and solution procedures have been explained and implemented into a computer code. The convergence of the iterative solution has been studied with clear definition for the cases at which the stability or material failures occur. The results of the developed solution procedure have been validated by comparing them with the existing solutions and the experimental results. The developed solution procedure provides a powerful tool to solve a wide range of problems related to stability of masonry walls and to check the existing empirical methods. © 2015 Elsevier Ltd.
Ludwig-Muller J.,TU Dresden
Journal of Experimental Botany | Year: 2011
Auxin conjugates are thought to play important roles as storage forms for the active plant hormone indole-3-acetic acid (IAA). In its free form, IAA comprises only up to 25% of the total amount of IAA, depending on the tissue and the plant species studied. The major forms of IAA conjugate are low molecular weight ester or amide forms, but there is increasing evidence of the occurrence of peptides and proteins modified by IAA. Since the discovery of genes and enzymes involved in synthesis and hydrolysis of auxin conjugates, much knowledge has been gained on the biochemistry and function of these compounds, but there is still much to discover. For example, recent work has shown that some auxin conjugate hydrolases prefer conjugates with longer-chain auxins such as indole-3-propionic acid and indole-3-butyric acid as substrate. Also, the compartmentation of these reactions in the cell or in tissues has not been resolved in great detail. The function of auxin conjugates has been mainly elucidated by mutant analysis in genes for synthesis or hydrolysis and a possible function for conjugates inferred from these results. In the evolution of land plants auxin conjugates seem to be connected with the development of certain traits such as embryo, shoot, and vasculature. Most likely, the synthesis of auxin conjugates was developed first, since it has been already detected in moss, whereas sequences typical of auxin conjugate hydrolases were found according to database entries first in moss ferns. The implications for the regulation of auxin levels in different species will be discussed. © 2010 The Author(s).
Ewing S.G.,University of Pittsburgh |
Ewing S.G.,TU Dresden |
Grace A.A.,University of Pittsburgh
Brain Stimulation | Year: 2013
Deep brain stimulation of the ventral striatum is an effective treatment for a variety of treatment refractory psychiatric disorders yet the mechanism of action remains elusive. We examined how five days of stimulation affected rhythmic brain activity in freely moving rats in terms of oscillatory power within, and coherence between, selected limbic regions bilaterally. Custom made bipolar stimulating/recording electrodes were implanted, bilaterally, in the nucleus accumbens core. Local field potential (LFP) recording electrodes were implanted, bilaterally in the prelimbic and orbitofrontal cortices and mediodorsal thalamic nucleus. Stimulation was delivered bilaterally with 100 μs duration constant current pulses at a frequency of 130 Hz delivered at an amplitude of 100 μA using a custom-made stimulation device. Synchronized video and LFP data were collected from animals in their home cages before, during and after stimulation. Signals were processed to remove movement and stimulation artifacts, and analyzed to determine changes in spectral power within, and coherence between regions. Five days stimulation of the nucleus accumbens core yielded temporally dynamic modulation of LFP power in multiple bandwidths across multiple brain regions. Coherence was seen to decrease in the alpha band between the mediodorsal thalamic nucleus and core of the nucleus accumbens. Coherence between each core of the nucleus accumbens bilaterally showed rich temporal dynamics throughout the five day stimulation period. Stimulation cessation revealed significant "rebound" effects in both power and coherence in multiple brain regions. Overall, the initial changes in power observed with short-term stimulation are replaced by altered coherence, which may reflect the functional action of DBS. © 2013 Elsevier Inc. All rights reserved.
Krauthauser H.G.,TU Dresden
IEEE Transactions on Electromagnetic Compatibility | Year: 2012
We derive equations to calculate the number of samples (tuner positions) required to achieve a certain inhomogeneity for the maximum of a rectangular field strength component with given confidence in reverberation chambers. Perfect and limited reverberation are investigated. The results are in good agreement with unreferenced values found in reverberation standards, e.g., IEC 61000-4-21. They can be used to a priori predict the required number of independent samples from the quality factor and the chamber volume only. Evidence is given that current homogeneity limits in standards (3 dB, IEC 61000-4-21) are inconsistent with the minimum number of samples to use (namely 12) at high frequencies. © 1964-2012 IEEE.
Dargie W.,TU Dresden
IEEE Sensors Journal | Year: 2012
In the last few years, interest in wireless sensor networks has increased considerably. These networks can be useful for a large number of applications, including habitat monitoring, structural health monitoring, pipeline monitoring, transportation, precision agriculture, supply chain management, and many more. Typically, a wireless sensor network consists of a large number of simple nodes which operate with exhaustible batteries, unattended. Manual replacement or recharging the batteries is not an easy or desirable task. Hence, how energy is utilized by the various hardware subsystems of individual nodes directly affects the scope and usefulness of the entire network. This paper provides a comprehensive assessment of state-of-the-art of dynamic power management (DPM) in wireless sensor networks. It investigates aspects of power dissipation in a node and analyses the strength and limitations of selective switching, dynamic frequency, and voltage scaling. © 2012 IEEE.
Manthey N.,TU Dresden
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2012
This paper presents the CNF simplifier Coprocessor 2.0, an extension of Coprocessor . It implements almost all currently known simplification techniques in a modular way and provides access to each single technique to execute them independently. Disabling preprocessing for a set of variables is also possible and enables to apply simplifications also for incremental SAT solving. Experiments show that Coprocessor 2.0 performs better than its predecessor or SatElite. © 2012 Springer-Verlag.
Vandewal K.,TU Dresden
Annual Review of Physical Chemistry | Year: 2016
Intermolecular charge transfer (CT) states at the interface between electron-donating (D) and electron-accepting (A) materials in organic thin films are characterized by absorption and emission bands within the optical gap of the interfacing materials. CT states efficiently generate charge carriers for some D-A combinations, and others show high fluorescence quantum efficiencies. These properties are exploited in organic solar cells, photodetectors, and light-emitting diodes. This review summarizes experimental and theoretical work on the electronic structure and interfacial energy landscape at condensed matter D-A interfaces. Recent findings on photogeneration and recombination of free charge carriers via CT states are discussed, and relations between CT state properties and optoelectronic device parameters are clarified. Copyright © 2016 by Annual Reviews. All rights reserved.
Okotrub A.V.,RAS Nikolaev Institute of Inorganic Chemistry |
Yudanov N.F.,RAS Nikolaev Institute of Inorganic Chemistry |
Asanov I.P.,RAS Nikolaev Institute of Inorganic Chemistry |
Vyalikh D.V.,TU Dresden |
Bulusheva L.G.,RAS Nikolaev Institute of Inorganic Chemistry
ACS Nano | Year: 2013
Highly oriented pyrolytic graphite characterized by a low misorientation of crystallites is fluorinated using a gaseous mixture of BrF3 with Br2 at room temperature. The golden-colored product, easily delaminating into micrometer-size transparent flakes, is an intercalation compound where Br2 molecules are hosted between fluorinated graphene layers of approximate C2F composition. To unravel the chemical bonding in semifluorinated graphite, we apply angle-resolved near-edge X-ray absorption fine structure (NEXAFS) spectroscopy and quantum-chemical modeling. The strong angular dependence of the CK and FK edge NEXAFS spectra on the incident radiation indicates that room-temperature-produced graphite fluoride is a highly anisotropic material, where half of the carbon atoms are covalently bonded with fluorine, while the rest of the carbon atoms preserve π electrons. Comparison of the experimental CK edge spectrum with theoretical spectra plotted for C2F models reveals that fluorine atoms are more likely to form chains. This conclusion agrees with the atomic force microscopy observation of a chain-like pattern on the surface of graphite fluoride layers. © 2012 American Chemical Society.
Sun Q.-C.,University of Tennessee at Knoxville |
Yadgarov L.,Weizmann Institute of Science |
Rosentsveig R.,Weizmann Institute of Science |
Seifert G.,TU Dresden |
And 2 more authors.
ACS Nano | Year: 2013
We investigated the optical properties of rhenium-doped MoS2 nanoparticles and compared our findings with the pristine and bulk analogues. Our measurements reveal that confinement softens the exciton positions and reduces spin-orbit coupling, whereas doping has the opposite effect. We model the carrier-induced exciton blue shift in terms of the Burstein-Moss effect. These findings are important for understanding doping and finite length scale effects in low-dimensional nanoscale materials. © 2013 American Chemical Society.
Hackert T.,University of Heidelberg |
Weitz J.,TU Dresden |
Buchler M.W.,University of Heidelberg
Langenbeck's Archives of Surgery | Year: 2014
Background: Extended resections in the upper GI tract, especially for pancreatic malignancies, can require resection of the hepatic or superior mesenteric artery. Besides venous or allogenous grafting, the splenic artery can be used for reconstruction in both positions. Purpose: We hereby describe the different technical possibilities of interposition or transposition to use the splenic artery for restoration of arterial perfusion of the liver or the small bowel following resection of the hepatic or superior mesenteric artery, respectively. Conclusion: The use of the splenic artery is a convenient and appropriate possibility to reconstruct the hepatic or superior mesenteric artery in pancreatic resection with regard to interposition and especially transposition of this vessel. It should be considered in patients suitable to undergo these procedures to extend resectability in pancreatic cancer surgery. © 2014 Springer-Verlag.
Zhu Y.,Japan National Institute of Materials Science |
Ikoma T.,Japan National Institute of Materials Science |
Hanagata N.,Japan National Institute of Materials Science |
Kaskel S.,TU Dresden
Small | Year: 2010
Rattle-type Fe304@SiO2 hollow mesoporous spheres with different particle sizes, different mesoporous shell thicknesses, and different levels of Fe3O4 content are prepared by using carbon spheres as templates. The effects of particle size and concentration of Fe304@SiO2 hollow mesoporous spheres on cell uptake and their in vitro cytotoxicity to HeLa cells are evaluated. The spheres exhibit relatively fast cell uptake. Concentrations of up to 150 μg mL-1 show no cytotoxicity, whereas a concentration of 200 μg mL-1 shows a small amount of cytotoxicity after 48 h of incubation. Doxorubicin hydrochloride (DOX), an anticancer drug, is loaded into the Fe304@SiO2 hollow mesoporous spheres, and the DOX-loaded spheres exhibit a somewhat higher cytotoxicity than free DOX. These results indicate the potential of Fe304@SiO 2 hollow mesoporous spheres for drug loading and delivery into cancer cells to induce cell death. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA.
Broll U.,TU Dresden
Spatial Economic Analysis | Year: 2010
This paper considers a model of spatial allocation of investment capital under uncertainty. We demonstrate that the spatial concentration of economic activity depends upon properties of risk preferences deeper than risk aversion. The degree of so-called relative prudence unambiguously decides whether or not the diversification of income risk favours the geographic dispersion of economic activity. In our framework we relate risk diversification with economic integration. Then there exists risk preferences so that spatial concentration of industry and capital is not affected by the degree of economic integration or segmentation of the regions. We also study the impact of net return regressibility upon spatial allocation. © 2010 Regional Studies Association.
Muench S.,TU Dresden
Journal of Cleaner Production | Year: 2015
In the European Union, the share of renewable energy has increased significantly over the past few years. Among renewable energy options, bioenergy is considered to be the dominant energy source. Previous literature is inconclusive regarding the suitability of bioenergy to mitigate greenhouse gases. The goal of this paper is to address this research gap. Life Cycle Assessments (LCAs) of biomass systems for electricity generation were gathered via a systematic literature review and form the empirical basis of this study. A quantitative exploratory analysis and a Qualitative Comparative Analysis were carried out to identify the greenhouse gas mitigation potential of different biomass systems used for electricity generation. Significant variations in LCA results are due to the heterogeneity of these systems; therefore, the transferability of LCA results to similar systems must be investigated on a case-by-case basis. Results show that electricity from biomass can be an appropriate measure for greenhouse gas mitigation in the European Union. To mitigate greenhouse gases, it is recommended to promote the employment of (1) non-dedicated lignocellulosic biomass with thermochemical conversion, (2) dedicated lignocellulosic biomass with thermochemical conversion, and (3) dedicated lignocellulosic biomass with direct combustion. For a more holistic assessment, future research should focus not only on greenhouse gas emissions, but also on other environmental, economic, and social impact categories. © 2014 Elsevier Ltd.
Pradelli L.,AdRes HE and OR |
Mayer K.,Justus Liebig University |
Muscaritoli M.,University of Rome La Sapienza |
Heller A.R.,TU Dresden
Critical Care | Year: 2012
Introduction: Previous studies and a meta-analysis in surgical patients indicate that supplementing parenteral nutrition regimens with n-3 polyunsaturated fatty acids (PUFAs), in particular eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), is associated with improved laboratory and clinical outcomes in the setting of hyper-inflammatory conditions. Refined or synthetic fish oils are commonly used as a source of EPA and DHA. The objective of the present meta-analysis was to evaluate n-3 PUFA-enriched parenteral nutrition regimens in elective surgical and intensive care unit (ICU) patients.Methods: Medline was searched for randomized controlled trials comparing n-3 PUFA-enriched lipid emulsions with standard non-enriched lipid emulsions (i.e. soybean oil, MCT/LCT or olive/soybean oil emulsions) in surgical and ICU patients receiving parenteral nutrition. Extracted data were pooled by means of both random and fixed effects models, and subgroup analyses were carried forward to compare findings in ICU versus non-ICU patients.Results: A total of 23 studies (n = 1502 patients: n = 762 admitted to the ICU) were included. No statistically significant difference in mortality rate was found between patients receiving n-3 PUFA-enriched lipid emulsions and those receiving standard lipid emulsions (RR= 0.89; 0.59, 1.33), possibly reflecting a relatively low underlying mortality risk. However, n-3 PUFA-enriched emulsions are associated with a statistically and clinically significant reduction in the infection rate (RR =0.61; 0.45, 0.84) and the lengths of stay, both in the ICU (-1.92; -3.27, -0.58) and in hospital overall (-3.29; -5.13, -1.45). Other beneficial effects included reduced markers of inflammation, improved lung gas exchange, liver function, antioxidant status and fatty acid composition of plasma phospholipids, and a trend towards less impairment of kidney function.Conclusions: These results confirm and extend previous findings, indicating that n-3 PUFAs-enriched parenteral nutrition regimens are safe and effective in reducing the infection rate and hospital/ICU stay in surgical and ICU patients. © 2012 Pradelli et al.; licensee BioMed Central Ltd.
Marquardt G.,TU Dresden
Health Environments Research and Design Journal | Year: 2011
Objective: This paper provides an overview of the available literature on architectural wayfinding design for people with dementia in nursing homes. The results were to be summarized and substantiated through an interdisciplinary interpretation, taking into account changes in the orientation process of people with dementia. Background: Spatial disorientation and declining wayfinding abilities are among the early symptoms of dementia, limiting a person's ability to perform activities of daily living (ADLs) independently and ultimately, perhaps leading to institutionalization. A prerequisite to maintaining residents' quality of life in a nursing home is their ability to orient themselves within their new environment. Approach: The available literature on wayfinding design for people with dementia in nursing homes was reviewed. Two aspects of interventions for residents' wayfinding abilities were identified: the design of the floor plan typology and environmental cues. Results: The design of the physical environment plays a major role in supporting the wayfinding abilities of people with dementia. The floor plan design of a nursing home in particular has a significant influence on residents' spatial orientation and wayfinding. Additional interventions such as signage, furnishing, lighting, and colors are additional supporting features but they cannot compensate for an adverse architectural design. Conclusions: For the creation of a supportive, dementia-friendly environment, both aspects of architectural design must be considered. Design guidelines to support the wayfinding abilities of people with dementia were developed to synthesize both. © 2011, Vendome Group, LLC.
Luhn G.,TU Dresden
Information (Switzerland) | Year: 2012
This first part of the study introduces an elementary concept of information. Our interest for newness, our curiosity in the new, will be considered as a main building block of information, and of reality itself. A typical definition of information (the reduction of uncertainty) needs to be fundamentally inverted: Information is a compositional activity, including the inconsistent, the paradox, the contradiction and the incoherent meaning. This study expands on the analysis of the composition of new structure (new macrophysical laws), and the analysis of the causality and causal state of such structures ("causally active symbols"). The classical, scientific-objective, passive understanding of information gives meaning to the fact that modern information technology does not by itself lead to an increase of human values. However, our social and moral stance is an informational one, and our informational, active conscious process holds the power to mediate and to enforce this process towards an enriched life. The indicator for such enrichment is given to us by information, and the knowledge about this process will feed us with energy to move towards an active spirit of ethics, and towards the information society. Part I of this study expands on the fundament basis and on our intrinsic responsibility to release the forces that are based on the active dimension of information. Those forces are required in order to reveal the so-called information society from its metaphorical character (Part II). © 2012 by the author.
Baburin I.A.,TU Dresden
Acta Crystallographica Section A: Foundations and Advances | Year: 2016
Using group-subgroup and group-supergroup relations, a general theoretical framework is developed to describe and derive interpenetrating 3-periodic nets. The generation of interpenetration patterns is readily accomplished by replicating a single net with a supergroup G of its space group H under the condition that site symmetries of vertices and edges are the same in both H and G. It is shown that interpenetrating nets cannot be mapped onto each other by mirror reflections because otherwise edge crossings would necessarily occur in the embedding. For the same reason any other rotation or roto-inversion axes from G\H are not allowed to intersect vertices or edges of the nets. This property significantly narrows the set of supergroups to be included in the derivation of interpenetrating nets. A procedure is described based on the automorphism group of a Hopf ring net [Alexandrov et al. (2012). Acta Cryst. A68, 484-493] to determine maximal symmetries compatible with interpenetration patterns. The proposed approach is illustrated by examples of twofold interpenetrated utp, dia and pcu nets, as well as multiple copies of enantiomorphic quartz (qtz) networks. Some applications to polycatenated 2-periodic layers are also discussed.A general theoretical framework based on group-subgroup and group-supergroup relations is proposed to describe and derive interpenetrating nets. © International Union of Crystallography, 2016.
Dobrev D.,TU Dresden |
Nattel S.,Montreal Heart Institute
The Lancet | Year: 2010
Inadequacies in current therapies for atrial fibrillation have made new drug development crucial. Conventional antiarrhythmic drugs increase the risk of ventricular proarrhythmia. In drug development, the focus has been on favourable multichannel-blocking profiles, atrial-specific ion-channels, and novel non-channel targets (upstream therapy). Molecular modification of the highly effective multichannel blocker, amiodarone, to improve safety and tolerability has produced promising analogues such as dronedarone, although this drug seems less effective than does amiodarone. Vernakalant, an atrial-selective drug with reduced proarrhythmic risk, might be useful for cardioversion in atrial fibrillation. Ranolazine, another atrial-selective agent initially developed as an antianginal, has efficacy for atrial fibrillation and is being tested in prospective clinical trials. So-called upstream therapy with angiotensin-converting enzyme and angiotensin-receptor inhibitors, statins, or omega-3 fatty acids and fish oil that target atrial remodelling could be effective, but need further clinical validation. We focus on the basic and clinical pharmacology of newly emerging antiarrhythmic drugs and non-traditional approaches such as upstream therapy for atrial fibrillation. © 2010 Elsevier Ltd. All rights reserved.
Vojta M.,TU Dresden
Physica C: Superconductivity and its Applications | Year: 2012
This article is devoted to a discussion of stripe and electron-nematic order and their connection to electronic properties in the pseudogap regime of copper-oxide superconductors. We review basic properties of these symmetry-breaking ordering phenomena as well as proposals which connect them to quantum-oscillation measurements. Experimental data indicate that these orders are unlikely to be the cause of the pseudogap phenomenon, implying that they occur on top of the pseudogap state which itself is of different origin. Specifically, we discuss the idea that the non-superconducting pseudogap ground state hosts electron-like quasiparticles which coexist with a spin liquid, realizing a variant of a fractionalized Fermi liquid. We speculate on how stripe order in such a pseudogap state might offer a consistent description of ARPES, NMR, quantum-oscillation, and transport data. © 2012 Elsevier B.V. All rights reserved.
Lotsch J.,Goethe University Frankfurt |
Geisslinger G.,Goethe University Frankfurt |
Hummel T.,TU Dresden
Trends in Pharmacological Sciences | Year: 2012
Advances in the understanding of the sense of smell have increased awareness of the role of olfaction in human life. Odors are perceived via specific G protein-coupled receptors (GPCRs) with cAMP as the second messenger. Drugs that interact with this signaling cascade, such as opioids, cannabinoids and sildenafil, are known to reduce olfactory function. Drugs that are active in the central nervous system (CNS) may also hinder the complex processing of olfactory information to distinguish, via pattern recognition, thousands of odors from the signals of only ∼400 distinct olfactory receptors. Many other interactions with drug targets expressed at the olfactory bulb are also likely to occur. However, olfactory drug effects have rarely been explored in controlled studies. In the current activities of drug development and re-purposing, olfaction could become highly important because it can impact significantly upon the enjoyment of food. With an established molecular basis and using available tools, the assessment of olfaction in drug development and approval is advised. © 2012 Elsevier Ltd.
Alcohol consumption, drinking patterns, and ischemic heart disease: a narrative review of meta-analyses and a systematic review and meta-analysis of the impact of heavy drinking occasions on risk for moderate drinkers
Roerecke M.,Center for Addiction and Mental Health |
Rehm J.,TU Dresden
BMC medicine | Year: 2014
BACKGROUND: Alcohol consumption is a major global risk factor for mortality and morbidity. Much discussion has revolved around the diverse findings on the complex relationship between alcohol consumption and the leading cause of death and disability, ischemic heart disease (IHD).METHODS: We conducted a systematic search of the literature up to August 2014 using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines to identify meta-analyses and observational studies examining the relationship between alcohol drinking, drinking patterns, and IHD risk, in comparison to lifetime abstainers. In a narrative review we have summarized the many meta-analyses published in the last 10 years, discussing the role of confounding and experimental evidence. We also conducted meta-analyses examining episodic heavy drinking among on average moderate drinkers.RESULTS: The narrative review showed that the use of current abstainers as the reference group leads to systematic bias. With regard to average alcohol consumption in relation to lifetime abstainers, the relationship is clearly J-shaped, supported by short-term experimental evidence and similar associations within strata of potential confounders, except among smokers. Women experience slightly stronger beneficial associations and also a quicker upturn to a detrimental effect at lower levels of average alcohol consumption compared to men. There was no evidence that chronic or episodic heavy drinking confers a beneficial effect on IHD risk. People with alcohol use disorder have an elevated risk of IHD (1.5- to 2-fold). Results from our quantitative meta-analysis showed that drinkers with average intake of <30 g/day and no episodic heavy drinking had the lowest IHD risk (relative risk = 0.64, 95% confidence interval 0.53 to 0.71). Drinkers with episodic heavy drinking occasions had a risk similar to lifetime abstainers (relative risk = 1.12, 95% confidence interval 0.91 to 1.37).CONCLUSIONS: Epidemiological evidence for a beneficial effect of low alcohol consumption without heavy drinking episodes is strong, corroborated by experimental evidence. However, episodic and chronic heavy drinking do not provide any beneficial effect on IHD. Thus, average alcohol consumption is not sufficient to describe the risk relation between alcohol consumption and IHD. Alcohol policy should try to reduce heavy drinking patterns.
Baraban L.,Leibniz Institute for Solid State and Materials Research |
Baraban L.,TU Dresden |
Harazim S.M.,Leibniz Institute for Solid State and Materials Research |
Sanchez S.,Leibniz Institute for Solid State and Materials Research |
And 2 more authors.
Angewandte Chemie - International Edition | Year: 2013
Chemotaxis in practice: Two different artificial catalytic micromotors (tubular and spherical, see scheme) show chemotactic behavior in microfluidic channels demonstrating that catalytic micromotors can sense the gradient of chemical fuel in their environment and be directed towards desired locations. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Roerecke M.,Center for Addiction and Mental Health |
Roerecke M.,University of Toronto |
Rehm J.,Center for Addiction and Mental Health |
Rehm J.,University of Toronto |
Rehm J.,TU Dresden
International Journal of Epidemiology | Year: 2014
Background: Alcohol use disorders (AUD) are highly disabling. Recent studies reported much higher relative risks for all-cause mortality in AUD patients compared with earlier studies. Systematic evidence regarding cause-specific mortality among AUD patients has been unavailable to date.Methods: Studies were identified through MEDLINE, EMBASE and Web of Science up to August 2012. Following MOOSE guidelines, prospective and historical cohort studies assessing cause-specific mortality risk from AUD patients at baseline compared with the general population were selected. Data on several study characteristics, including AUD assessment, follow-up period, setting, location and cause-specific mortality risk compared with the general population were abstracted. Random-effect meta-analyses were conducted.Results: Overall, 17 observational studies with 6420 observed deaths among 28 087 AUD patients were included. Pooled standardized mortality ratios (SMRs) after 10 years of follow-up among men were 14.8 (95% confidence interval: 8.7-24.9) for liver cirrhosis, 18.0 (11.2-30.3) for mental disorders, 6.6 (5.0-8.8) for death by injury and around 2 for cancer and cardiovascular diseases. SMRs were substantially higher in women, with fewer studies available. For many outcomes the risk has been increasing substantially over time.Conclusions: Cause-specific mortality among AUD patients was high in all major categories compared with the general population. There has been a lack of recent research, and future studies should focus on the influence of comorbidities on excess mortality risk among AUD patients. Efforts to reduce these risks should be a priority, given that successful treatment reduces mortality risk substantially for a relatively common psychiatric disease. © The Author 2014; all rights reserved. Published by Oxford University Press on behalf of the International Epidemiological Association.
Schmitt J.,TU Dresden |
Langan S.,University of Pennsylvania |
Stamm T.,Medical University of Vienna |
Williams H.C.,University of Nottingham
Journal of Investigative Dermatology | Year: 2011
There is wide variation in the use of outcome measures for eczema. We performed a three-stage web-based international Delphi exercise to develop consensus-based sets of core outcome domains for eczema for controlled trials and clinical recordkeeping. A total of 57 individuals from four stakeholder groups (consumers, clinical experts, regulatory agency representatives, and journal editors) representing 13 countries were asked to rate the importance of 19 outcome domains for eczema and to choose which domains should be included in two core sets of outcomes. Forty-six individuals (81%) participated. Participants received standardized feedback, including the group median, interquartile range, and previous responses, and the assessment was repeated in two subsequent rounds. We defined consensus a priori if at least 60% of the members of at least three stakeholder groups, including consumers, recommended domain inclusion in the core set. Consensus was achieved for inclusion of symptoms, physician-assessed clinical signs, and a measurement for long-term control of flares in the core set of outcome domains for eczema trials. We recommend including these three core outcomes in future eczema trials in order to enhance clinical interpretability and to enable meta-analyses across different studies. For recordkeeping, consensus was reached to regularly monitor eczema symptoms in clinical practice. Future work is needed to select which existing or new scales should be used to measure the domains identified as relevant for the core set. © 2011 The Society for Investigative Dermatology.
von Dawans B.,Albert Ludwigs University of Freiburg |
Kirschbaum C.,TU Dresden |
Heinrichs M.,Albert Ludwigs University of Freiburg
Psychoneuroendocrinology | Year: 2011
Psychological stress is an ubiquitous challenge across human cultures affecting mental and physical health. Recent evidence indicates that performance tasks combining elements of socio-evaluative threat and uncontrollability elicit reliable stress responses. The Trier Social Stress Test (TSST) is the most frequently used psychological protocol in stress research; however, to date it has only been available in a single-subject version. In particular, there is an increasing need in several emerging research fields such as stress research or social neurosciences for a standardized research tool to expose relatively large groups of subjects to controlled simultaneous stress. In search of a laboratory stressor that allows simultaneous stress exposure in a group format, we exposed a total of 25 healthy male participants to the Trier Social Stress Test for Groups (TSST-G; public speaking and mental arithmetic tasks in front of a panel of two evaluators in groups of six participants) and a specific control condition. Results showed that the TSST-G induced significant increases in cortisol, heart rate, and psychological stress responses. The TSST-G provides a novel, effective, and economical protocol for experimental paradigms requiring simultaneous stress induction in multiple participants. © 2010 Elsevier Ltd.
Ocklenburg S.,Ruhr University Bochum |
Beste C.,TU Dresden |
Arning L.,Ruhr University Bochum |
Peterburs J.,Johns Hopkins University |
Gunturkun O.,Ruhr University Bochum
Neuroscience and Biobehavioral Reviews | Year: 2014
Dominance of the left hemisphere for many aspects of speech production and perception is one of the best known examples of functional hemispheric asymmetries in the human brain. Classic theories about its ontogenesis assume that it is determined by the same ontogenetic factors as handedness because the two traits are correlated to some extent. However, the strength of this correlation depends on the measures used to assess the two traits, and the neurophysiological basis of language lateralization is different from that of handedness. Therefore, we argue that although the two traits show partial pleiotropy, there is also a substantial amount of independent ontogenetic influences for each of them. This view is supported by several recent genetic and neuroscientific studies that are reviewed in the present article. © 2014 Elsevier Ltd.
Park J.-H.,TU Dresden
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2014
Charged lepton flavor violation is reappraised in the context of a supersymmetric seesaw mechanism. It is pointed out that a nontrivial flavor structure of right-handed neutrinos, whose effect has been thus far less studied, can give rise to significant slepton flavor transitions. Under the premise that the neutrino Yukawa couplings are of O(1), the right-handed neutrino mixing contribution could form a basis of the μ→eγ amplitude, which by itself might lead to an experimentally accessible rate, given a typical low-energy sparticle spectrum. Emphasis is placed on the crucial role of the recently measured lepton mixing angle θ13 as well as the leptonic CP-violating phases. © 2014 American Physical Society.
Weiss N.,TU Dresden
Seminars in Dialysis | Year: 2012
Lipid apheresis effectively lowers LDL-cholesterol even in drug-unresponsive severely hypercholesterolemic patients. This results in improvement of symptoms of coronary artery disease, reduces progression of coronary atherosclerosis, and decreases coronary event rates. Besides aggressive lipid lowering itself, these effects may also be due to nonselective removal of other high molecular weight proteins leading to improved hemorheology. Lipid apheresis is also used for treating symptoms of vascular diseases outside the coronary arteries, such as peripheral arterial disease and the angioneuropathic diabetic foot syndrome. This review discusses putative effects of lipid apheresis and rheophereis on restoring pathophysiological processes involved in the development of symptoms of peripheral arterial disease, critical limb ischemia, and the diabetic foot syndrome. The clinical experience with lipid apheresis and rheopheresis in treating patients with peripheral arterial disease and the diabetic foot syndrome is critically reviewed and put into the context of currently available established treatment options. Based on this analysis, the limitations of current evidence are discussed and potential fields of research are suggested. © 2011 Wiley Periodicals, Inc.
Pauly S.,Leibniz Institute for Solid State and Materials Research |
Gorantla S.,Leibniz Institute for Solid State and Materials Research |
Wang G.,Leibniz Institute for Solid State and Materials Research |
Kuhn U.,Leibniz Institute for Solid State and Materials Research |
And 2 more authors.
Nature Materials | Year: 2010
Bulk metallic glasses (BMGs) generally fail in a brittle manner under uniaxial, quasistatic loading at room temperature. The lack of plastic strain is a consequence of shear softening, a phenomenon that originates from shear-induced dilation that causes plastic strain to be highly localized in shear bands. So far, significant tensile ductility has been reported only for microscopic samples of around 100 nm (ref.Â 4) as well as for high strain rates, and so far no mechanisms are known, which could lead to work hardening and ductility in quasistatic tension in macroscopic BMG samples. In the present work we developed CuZr-based BMGs, which polymorphically precipitate nanocrystals during tensile deformation and subsequently these nanocrystals undergo twinning. The formation of such structural heterogeneities hampers shear band generation and results in macroscopically detectable plastic strain and work hardening. The precipitation of nanocrystals and their subsequent twinning can be understood in terms of a deformation-induced softening of the instantaneous shear modulus. This unique deformation mechanism is believed to be not just limited to CuZr-based BMGs but also to promote ductility in other BMGs. © 2010 Macmillan Publishers Limited. All rights reserved.
Gaponik N.,TU Dresden
Journal of Materials Chemistry | Year: 2010
Nowadays assembly approaches are recognized as being the main working tool of bottom up chemical nanotechnology. The assembly of strongly emitting semiconductor nanocrystals can be performed on flat, porous and spherical surfaces and thus are very important for thin-film technologies, doping of mesoporous materials, modification of pre-patterned substrates, the creation of microshells and cavities, etc. Self-assembly approaches or the use of removable templates make possible the formation of nanowires, nanosheets or nanoporous 3D ordered materials created solely from the assembled nanoparticles. Hierarchical assembling and assembling of nanocrystals with other organic or inorganic entities opens up the possibility to achieve composites with literally unlimited functionalities. The understanding and governing of charge and energy transfer processes between the components of the composites are the key points in their efficient utilization as building blocks in novel types of LEDs, photovoltaic and photonic devices and various optical sensors. © 2010 The Royal Society of Chemistry.
Ruck M.,TU Dresden
Zeitschrift fur Kristallographie | Year: 2010
One of the main classifications of materials uses the categories of metals, semiconductors and insulators. However, the boundaries are vague. In so-called confined metals the mobility of conduction electrons is restricted by at least one of the following circumstances: (a) Tendency towards electronic localization in covalent bonds, on ions or in lone-pairs (chemical confinement), (b) Contrast of bonding interactions in adjacent parts of the structure, i.e. separation of metallic and non-metallic domains (structural confinement), (c) Reduced size of metallic particles (size confinement). One playground for the investigation of the properties of matter at the limit of the metallic state is the chemistry of low-valent bismuth compounds, from which metallic nanotubes and nanorods, crystalline metal/salt hybrids, low-dimensional metals and unique clusters emerge. Strange physical effects, like coexistence of ferromagnetism and superconductivity, are found. © by Oldenbourg Wissenschaftsverlag, München.
Barreiro A.,Technical University of Delft |
Borrnert F.,Leibniz Institute for Solid State and Materials Research |
Rummeli M.H.,Leibniz Institute for Solid State and Materials Research |
Rummeli M.H.,TU Dresden |
And 2 more authors.
Nano Letters | Year: 2012
Graphene and few-layer graphene at high bias expose a wealth of phenomena due to the high temperatures reached. With in situ transmission electron microscopy, we observe directly how the current modifies the structure, and vice versa. In some samples, cracks propagate from the edges of the flakes, leading to the formation of narrow constrictions or to nanometer spaced gaps after breakdown. In other samples, we find layer-by-layer evaporation of few-layer graphene, which could be exploited for the controlled production of single layer graphene from multilayered samples. Surprisingly, we even find that two pieces of graphene that overlap can heal out at high bias and form one continuous sheet. These findings open up new avenues to structure graphene for specific device applications. © 2012 American Chemical Society.