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Bochum, Germany

Ruhr University Bochum , located on the southern hills of central Ruhr area Bochum, was founded in 1962 as the first new public university in Germany since World War II. Instruction began in 1965.The Ruhr-University Bochum is one of the largest universities in Germany and part of the Deutsche Forschungsgemeinschaft, the most important German research funding organization.The RUB has been very successful in the Excellence Initiative by the German Federal and State Governments , a competition among Germany's most prestigious universities. It was one of the few institutions left competing for the title of an "elite university", but did not succeed in the last round of the competition. There are currently nine universities in Germany that hold this title.The University of Bochum was one of the first universities in Germany to introduce international Bachelor and Master degrees, which replaced the traditional German Diplom and Magister. Except for a few special cases this process has been completed and all degrees been converted. Today, the university offers a total of 150 different study programs from all fields.Ruhr University is financed and administered by the state of North Rhine-Westphalia. Currently, 38,675 students are enrolled, and the university employs over 5,500 staff , making it one of the ten largest universities in Germany . Kurt Biedenkopf, who later became prime minister of the state of Saxony, was director of the university from 1967 to 1969.Unlike a number of traditional universities, the buildings of Ruhr University are all centralized on one campus, except for the Faculty of Medicine, which also includes some hospitals in Bochum and the Ruhr area. Although the centralized university campus utilizes 1960s architecture almost exclusively, mainly consisting of 14 almost identical high-rise buildings, it is located at the edge of a green belt on high ground adjacent to the Ruhr valley. Wikipedia.

Eliasson B.,Ruhr University Bochum
Modern Physics Letters B | Year: 2013

This brief review is devoted to full-scale numerical modeling of the nonlinear interactions between electromagnetic (EM) waves and the ionosphere, giving rise to ionospheric Langmuir turbulence. A numerical challenge in the full-scale modeling is that it involves very different length-and time-scales. While the EM waves have wavelengths of the order 100 meters, the ionospheric Langmuir turbulence involving electrostatic waves and nonlinear structures can have wavelengths below one meter. A full-scale numerical scheme must resolve these different length-and time-scales, as well as the ionospheric profile extending vertically hundreds of kilometers. To overcome severe limitations on the timestep and computational load, a non-uniform nested grid method has been devised, in which the EM wave is represented in space on a relatively coarse grid with a spacing of a few meters, while the electrostatic wave turbulence is locally resolved on a much denser grid in space at the critical layer where the turbulence occurs. Interpolation and averaging schemes are used to communicate values of the EM fields and current sources between the coarse and dense grids. In this manner, the computational load can be drastically decreased, making it possible to perform full-scale simulations that cover the different time-and space-scales. We discuss the simulation methods and how they are used to study turbulence, stimulated EM emissions, particle acceleration and heating, and the formation of artificial ionospheric plasma layers by ionospheric Langmuir turbulence. © 2013 World Scientific Publishing Company.

Epelbaum E.,Ruhr University Bochum
Few-Body Systems | Year: 2013

Chiral effective field theory provides a systematic tool to study few-nucleon dynamics based on the approximate and spontaneously broken chiral symmetry of QCD. I discuss applications of this method to nuclear forces and few-nucleon dynamics. Various related topics including recent advances in nuclear lattice simulations are also addressed. © 2012 Springer-Verlag.

Kley R.A.,Ruhr University Bochum | Fischer D.,University of Basel
European Radiology | Year: 2010

Driven by increasing numbers of newly identified genetic defects and new insights into the field of inherited muscle diseases, neuromuscular imaging in general and magnetic resonance imaging (MRI) in particular are increasingly being used to characterise the severity and pattern of muscle involvement. Although muscle biopsy is still the gold standard for the establishment of the definitive diagnosis, muscular imaging is an important diagnostic tool for the detection and quantification of dystrophic changes during the clinical workup of patients with hereditary muscle diseases. MRI is frequently used to describe muscle involvement patterns, which aids in narrowing of the differential diagnosis and distinguishing between dystrophic and non-dystrophic diseases. Recent work has demonstrated the usefulness of muscle imaging for the detection of specific congenital myopathies, mainly for the identification of the underlying genetic defect in core and centronuclear myopathies. Muscle imaging demonstrates characteristic patterns, which can be helpful for the differentiation of individual limb girdle muscular dystrophies. The aim of this review is to give a comprehensive overview of current methods and applications as well as future perspectives in the field of neuromuscular imaging in inherited muscle diseases. We also provide diagnostic algorithms that might guide us through the differential diagnosis in hereditary myopathies. © 2010 The Author(s).

Stormer M.,Universitatsklinikum Cologne | Vollmer T.,Ruhr University Bochum
Transfusion Medicine and Hemotherapy | Year: 2014

Bacterial contamination of blood components and the prevention of transfusion-associated bacterial infection still remains a major challenge in transfusion medicine. Over the past few decades, a significant reduction in the transmission of viral infections has been achieved due to the introduction of mandatory virus screening. Platelet concentrates (PCs) represent one of the highest risks for bacterial infection. This is due to the required storage conditions for PCs in gas-permeable containers at room temperature with constant agitation, which support bacterial proliferation from low contamination levels to high titers. In contrast to virus screening, since 1997 in Germany bacterial testing of PCs is only performed as a routine quality control or, since 2008, to prolong the shelf life to 5 days. In general, bacterial screening of PCs by cultivation methods is implemented by the various blood services. Although these culturing systems will remain the gold standard, the significance of rapid methods for screening for bacterial contamination has increased over the last few years. These new methods provide powerful tools for increasing the bacterial safety of blood components. This article summarizes the course of policies and provisions introduced to increase bacterial safety of blood components in Germany. Furthermore, we give an overview of the different diagnostic methods for bacterial screening of PCs and their current applicability in routine screening processes. © 2014 S. Karger GmbH, Freiburg.

Zittermann A.,Ruhr University Bochum | Iodice S.,Italian National Cancer Institute | Pilz S.,Medical University of Graz | Grant W.B.,Nutrition and Health Research Center | And 3 more authors.
American Journal of Clinical Nutrition | Year: 2012

Background: Low vitamin D status may increase mortality risk. Objective: We used nonparametric ("highest compared with lowest"categories) and parametric (>2 categories) statistical models to evaluate associations of 25-hydroxyvitamin D [25(OH)D] serum concentrations and mortality in observational studies among general populations. Design: We searched PubMed, EMBASE, Web of Science, and reference lists for relevant articles. We included studies that contained data on relative risks (RRs) for mortality for different 25(OH)D concentrations, which included a corresponding measure of uncertainty, and this yielded 14 prospective cohort studies that involved 5562 deaths out of 62,548 individuals. We applied logtransformed RRs and CIs, adjusted for the maximal number of confounding variables. In the parametric model, which is based on 11 studies and 59,231 individuals, we used the lowest quantile as the reference category. Results: For "highest compared with lowest" categories of 25(OH)D, the estimated summary RR of mortality was 0.71 (95% CI: 0.50, 0.91). In the parametric model, the estimated summary RRs (95% CI) of mortality were 0.86 (0.82, 0.91), 0.77 (0.70, 0.84), and 0.69 (0.60, 0.78) for individuals with an increase of 12.5, 25, and 50 nmol 25(OH)D serum values/L, respectively, from a median reference category of ∼27.5 nmol/L. There was, however, no significant decrease in mortality when an increase of ∼87.5 nmol/L above the reference category occurred. Conclusion: Data suggest a nonlinear decrease in mortality risk as circulating 25(OH)D increases, with optimal concentrations ∼75-87.5 nmol/L. © 2012 American Society for Nutrition.

Ermolaev V.,University of Groningen | Kulske C.,Ruhr University Bochum
Journal of Statistical Physics | Year: 2010

We consider the Curie-Weiss model at initial temperature 0<β-1≤∞ in vanishing external field evolving under a Glauber spin-flip dynamics with temperature 0<β′-1≤∞. We study the limiting conditional probabilities and their continuity properties and discuss their set of points of discontinuity (bad points). We provide a complete analysis of the transition between Gibbsian and non-Gibbsian behavior as a function of time, extending earlier work for the case of independent spin-flip dynamics. For initial temperature β-1>1 we prove that the time-evolved measure stays Gibbs forever, for any (possibly low) temperature of the dynamics. In the regime of heating to low-temperatures from even lower temperatures, 0<β-1

Lytoceratites together with Phylloceratites are often described as "conservative". However, the origin and monophyly of lytoceratid ammonites as well as their role in the evolution of all ammonites is under constant debate. In this work, the Lytoceratoidea investigated on generic level for the presence of a septal lobe. Included into this investigation is the verification of relevant literature and the registration of the collected literature in a database system. furthermore material from public and private collections was studied. The investigation reveals that all Lytoceratoidea are characterised by the presence of a septal lobe which constitutes their monophyly (cp. ARKELL et al., 1957). The septal lobe represents a consistent morphological character that appeared in the lowermost Jurassic and is present in the uppermost Cretaceous members of Lytoceratoidea. It was noticed that the septal lobe appeared earlier in ontogeny and was stronger developed in most of the stratigraphical younger representatives compared to Jurassic members (acceleration). In addition, further characters have been investigated and tested for their phylogenetic significance. It turned out that most of these characters e. g. whorl section, course and number of constrictions are homoplastic or highly variable within one genus. Finally, six characters (septal lobe, parabolic ribs, fimbriation, shape of adult lateral lobe, primary suture, jaw type) have been kept for stratocladistic analyses. With this method the phylogeny within the Lytoceratoidea was enlightened as far as possible. Within the family Lytoceratidae five monophyletic subfamilies are retained: Ectocentritinae, Pleuroacanthinae, Lytoceratinae, alocolytoceratinae and megalytoceratinae. The monophyly of the second family Tetragonitidae is based on the distribution of the quinque-and sixlobate primary suture line and the development of a rhynchaptychus (ENGESER & KEUPP, 2002). Within the Tetragonitidae two subfamilies (Gaudryceratinae and Tetragonitinae) and one tribus Gabbioceratini are retained. This work has been the first critical-systematical review for the whole group within the last forty years. as a main result of this investigation fifteen genera have been excluded from Lytoceratoidea, seventeen genera have been regarded as junior subjective synonyms. a sexual dimorphic couple is presented for Anagaudryceras (m) and Anagaudryceras (Zelandites [m]) for the first time in addition to the two well known of Lytoceras (m). Thirty genera have been retained as valid lytoceratid taxa. for some genera e. g. Lobolytoceras and Protetragonites the stratigraphic distribution has been extended significantly. "Trachyphyllites" costatus is included into Analytoceras hermanni and represents a typical Lower Jurassic lytoceratid member. It appears that the Lytoceratoidea are derived from psiloceratids at the Triassic-Jurassic-boundary as already stated by GUEX (1987). The author assents the statement of GUEX (1987) and regards the Lytoceratoidea as members of ammonitina. Tetragonitidae are derived from Protetragonites. Both taxa develop non-fimbriate ribs in contrast to contemporary lytoceratids. Protetragonites fraasi from the oxfordian (Upper Jurassic) represents the oldest member of that genus. Judging from the two characters sixlobate primary suture and septal lobe, discussed above, Lytoceratoidea represent the most advanced ammonoid group. In the second part of this thesis the functional significance of the septal lobe was investigated. It was planned to calculate the ratio of chamber volume against its surface. for this purpose a Gaudryceras specimen in hollow preservation was scanned using computer tomography at the "Bundesanstalt für materialforschung und-prüfung" (Berlin). The ammonite was digitalised at "Konrad-Zuse-Institut" (Berlin) using amIRa®. Unfortunately, the resolution was too low for the project. The positive effect of the ratio of chamber volume against its surface caused by the septal lobe can therefore only be assumed. It is supposed that the septal lobe increases the efficiency of the hydrostatic apparatus.

Eliasson B.,Ruhr University Bochum
Transport Theory and Statistical Physics | Year: 2010

We present a review of recent developments of simulations of the Vlasov-Maxwell system of equations using a Fourier transform method in velocity space. In this method, the distribution functions for electrons and ions are Fourier transformed in velocity space, and the resulting set of equations are solved numerically. In the original Vlasov equation, phase mixing may lead to an oscillatory behavior and sharp gradients of the distribution function in velocity space, which is problematic in simulations where it can lead to unphysical electric fields and instabilities and to the recurrence effect where parts of the initial condition recur in the simulation. The particle distribution function is in general smoother in the Fourier-transformed velocity space, which is desirable for the numerical approximations. By designing outflow boundary conditions in the Fourier-transformed velocity space, the highest oscillating terms are allowed to propagate out through the boundary and are removed from the calculations, thereby strongly reducing the numerical recurrence effect. The outflow boundary conditions in higher dimensions including electromagnetic effects are discussed. The Fourier transform method is also suitable to solve the Fourier-transformed Wigner equation, which is the quantum mechanical analogue of the Vlasov equation for classical particles. © Taylor & Francis Group, LLC.

Polychaetes in the Southern Ocean are often thought to have wide distribution ranges on a horizontal and vertical scale. Here, this theory is tested for specimens commonly identified as the widely distributed glycerid Glycera kerguelensis using two molecular markers, the mitochondrial cytochrome oxidase c subunit I (COI) and the nuclear 28S rDNA. Identical morphospecies of three "populations" from three different habitats and two depth zones (abyssal plain 5,300 m, continental slope 2,000 m, sea mountain plateau 2,000 m) are compared. High genetic distances suggest the existence of three clades representing distinct species, identifying the investigated specimens as a complex comprising cryptic species with vertically restricted distribution. Two clades were found in sympatry on the Atka Bay slope in 2,000 m depth, one of these also found in similar depth on the plateau of the sea mountain Maud Rise. The third clade was limited to the abyssal plains (5,300 m) indicating the strong role of depth in the distribution of clades, possibly in conjunction with prevailing current systems. Evolution of the different clades is suggested to have resulted from a single emergence event with the origin of clades lying in the abyss. © 2010 Springer-Verlag.

Akbari-Moghanjoughi M.,Ruhr University Bochum | Akbari-Moghanjoughi M.,Shahid Madani University of Azarbaijan
Physics of Plasmas | Year: 2013

In this paper, it is shown that a mass density limit exists beyond which the relativistically degenerate matter would crystallize. The mass density limit, found here, is quite analogous to the mass limit predicted by Chandrasekhar for a type of compact stars called white dwarfs (M C h ≃ 1.43 Solar Mass). In this study, the old problem of white dwarf core collapse, which has been previously investigated by Chandrasekhar using hydrostatic stability criteria, is revisited in the framework of the quantum hydrodynamics model by inspection of the charge screening at atomic scales in the relativistic degeneracy plasma regime taking into account the relativistic Fermi-Dirac statistics and electron interaction features such as the quantum statistical pressure, Coulomb attraction, electron exchange-correlation, and quantum recoil effects. It is revealed that the existence of ion correlation and crystallization of matter in the relativistically degenerate plasma puts a critical mass density limit on white dwarf core region. It is shown that a white dwarf star with a core mass density beyond this critical limit can undergo the spontaneous core collapse (SCC). The SCC phenomenon, which is dominantly caused by the electron quantum recoil effect (interference and localization of the electron wave function), leads to a new exotic state of matter. In such exotic state, the relativistic electron degeneracy can lead the white dwarf crystallized core to undergo the nuclear fusion and an ultimate supernova by means of the volume reduction (due to the enhanced compressibility) and huge energy release (due to the increase in cohesive energy), under the stars huge inward gravitational pressure. Moreover, it is found that the SCC phenomenon is significantly affected by the core composition (it is more probable for heavier plasmas). The critical mass density found here is consistent with the values calculated for core density of typical white dwarf stars. © 2013 AIP Publishing LLC.

Blauert J.,Ruhr University Bochum
Acta Acustica united with Acustica | Year: 2013

The so-called Quality-of-the-Acoustics, QoA, is a commonly used descriptor of how we experience listening in performance spaces. Although the term is quite popular, particularly among non-acousticians, it is not well defined scientifically. A closer look shows that QoA is a complex and multi-layered issue. When analyzing or modelling the formation process of QoA, a variety of quality features have to be taken into account, whereby the actual relevance and salience of each of them is situation- and user-specific. In the first part of the article, the architecture of a general conceptual model of the processes involved in the formation of aural quality at large is presented, and an adequate system of layers of reference with respect to QoA is identified, whereby aspects of psycho-acoustics, perceptual psychology, physics, and communication science are considered. Effort is put into an attempt to discuss the different aspects of aural quality in a unified way, so that the general concept does not change due to specific applications or specific listeners, rather, it is only the set of references that has to be adapted specifically to a particular application. Some problems regarding identification and specification of proper references are discussed in more detail. The issues of objectivity and validity are touched upon in this context. In the second part of the article, some specific aspects with respect to the QoA of performance spaces are reflected, namely, functional adequacy, typicality, listening tradition and aesthetics. The discussion reveals a cross-cultural, universal validity of the concepts considered, thus making them a useful framework for organizing and analyzing relevant features of QoA in a broad range of performance spaces from the ancient ages up to modern times. The last part deals with current efforts to enable computer-aided instrumental evaluation and assessment of QoA. © S. Hirzel Verlag · EAA.

Moreno Catala M.,Humboldt University of Berlin | Woitalla D.,Ruhr University Bochum | Arampatzis A.,Humboldt University of Berlin
Neurorehabilitation and Neural Repair | Year: 2013

Background. Muscle weakness in old Parkinson's disease (PD) patients has been shown to impair their mobility, although the specific origin of this weakness and its relation to falls has not been well examined in young patients. Objective. This study aimed to analyze the possible contribution of central factors to muscle weakness of the triceps surae and quadriceps femoris muscles in young faller and nonfaller PD patients. Methods. Twenty-six young PD patients (fallers, n = 13 and nonfallers, n = 13) and 15 matched healthy controls performed several isometric maximal voluntary knee extension and plantar flexion contractions (MVC) of the most affected leg on a dynamometer. We estimated the maximal resultant agonist moments, the antagonistic moment of hamstrings and tibialis anterior during MVCs and the activation deficit of the quadriceps femoris and triceps surae muscles. Results. Only the Parkinson fallers showed significantly lower muscle strength, higher antagonistic moments and higher activation deficit compared with controls. Multiple regression analysis showed that the antagonistic moments and the activation deficit explained about 39% and 27%, of the variance in the maximal resultant moments of the knee extensors and the plantar flexors, respectively. Conclusions. Our findings suggest that Parkinson fallers are affected by strength impairments arising from the central nervous system and not from the peripheral muscle contractile capacity, even at early stages of the disease and young age. High-intensity resistance training may help enhance neural drive and decrease unwanted antagonistic moments and reduce the risk of falls. © The Author(s) 2013.

Kessler H.,Ruhr University Bochum | Stasch M.,University of Heidelberg | Cierpka M.,University of Heidelberg
Frontiers in Human Neuroscience | Year: 2013

This theoretical article makes a contribution to the field of "psychoanalytically informed neuroscience". First, central characteristics of psychoanalysis and neuroscience are briefly described leading into three epistemic dichotomies. Neuroscience versus psychoanalysis display almost opposing methodological approaches (reduction vs. expansion), test quality emphases (reliability vs. validity) and meaning of results (correlation vs. explanation). The critical point is to reach an intermediate level: in neuroscience an adequate position integrating both aspects-objective and subjective-of dual-aspect monism, and in psychoanalysis the appropriate level for the scientific investigation of its central concepts. As a suggestion to reach that level in both fields the system of Operationalized Psychodynamic Diagnosis (OPD; OPD Task Force, 2008) is presented. Combining aspects of both fields areas, expansion and reduction as well as reliability and validity, OPD could be a fruitful tool to transfer psychodynamic constructs into neuroscience. The article closes with a short description of recent applications of OPD in neuroscience. © 2013 Kessler, Stasch and Cierpka.

Bondu R.,Ruhr University Bochum
New directions for youth development | Year: 2011

School homicides have been become a worldwide phenomenon. In the decade following the Columbine shooting there have been at least forty similar events in other countries. This article addresses the international scope of this problem and some of the complex conceptual issues that make student homicidal violence difficult to define and study. Meaningful research on risk and protective factors that can inform evidence-based preventive models is summarized. Copyright © 2011 Wiley Periodicals, Inc., A Wiley Company.

Akbari-Moghanjoughi M.,Shahid Madani University of Azarbaijan | Akbari-Moghanjoughi M.,Ruhr University Bochum
Physics of Plasmas | Year: 2013

In this paper, by using a quantum hydrodynamic plasma model which incorporates the important quantum statistical pressure and electron diffraction force, we present the corrected plasmon dispersion relation for graphene which includes a k4 quantum term arising from the collective electron density wave interference effects. This correction may well describe the shortcoming of the previous results based on the classical hydrodynamics and confirms that the quantum hydrodynamic model may be as effective as the random phase approximation in successful description of the collective density excitations in quantum plasmas. It is clearly observed that the quantum correction due to the collective interaction of electron waves gives rise to significant contribution in the dispersion behavior of the collective plasmon density waves in a wide range of wavelength, as a fundamental property of the monolayer atom-thick graphene. It is revealed that the plasmon density-perturbation linear phase-speed in graphene possesses some universal minimum characteristic value, in the absence of an external magnetic field. It is further remarked that such correction also has important effect on the dielectric function, hence on the impurity screening, in graphene. © 2013 AIP Publishing LLC.

Bui T.Q.,University of Siegen | Nguyen M.N.,Ruhr University Bochum | Zhang C.,University of Siegen
Computational Mechanics | Year: 2011

A detailed analysis of natural frequencies of laminated composite plates using the meshfree moving Kriging interpolation method is presented. The present formulation is based on the classical plate theory while the moving Kriging interpolation satisfying the delta property is employed to construct the shape functions. Since the advantage of the interpolation functions, the method is more convenient and no special techniques are needed in enforcing the essential boundary conditions. Numerical examples with different shapes of plates are presented and the achieved results are compared with reference solutions available in the literature. Several aspects of the model involving relevant parameters, fiber orientations, lay-up number, length-to-length, stiffness ratios, etc. affected on frequency are analyzed numerically in details. The convergence of the method on the natural frequency is also given. As a consequence, the applicability and the effectiveness of the present method for accurately computing natural frequencies of generally shaped laminates are demonstrated. © 2011 Springer-Verlag.

Kley R.A.,Ruhr University Bochum
Current Opinion in Neurology | Year: 2016

PURPOSE OF REVIEW: Myofibrillar myopathies (MFMs) are hereditary muscle disorders characterized by distinct histopathological features. This review provides an overview of recent research with respect to new disease genes, clinical phenotypes, insights into pathomechanisms and therapeutic strategies. RECENT FINDINGS: Beyond the known disease genes DES, FLNC, MYOT, CRYAB, ZASP, BAG3, FHL1 and TTN, mutations in PLEC, ACTA1, HSPB8 and DNAJB6 have also been associated with a MFM phenotype. Proteomic analysis revealed new information about the composition of protein aggregates in myotilinopathy and identified a new diagnostic marker. New animal models mirror central aspects of MFM pathology and novel therapeutic strategies for treatment of MFM were evaluated in cell and animal models. SUMMARY: MFMs are an expanding and numerically significant group of protein aggregate diseases with marked clinical and genetic heterogeneity. Though no specific therapy is currently available, the generation of patient-mimicking cell and animal models now paves the way for the preclinical evaluation of novel therapeutic strategies. Copyright © 2016 Wolters Kluwer Health, Inc. All rights resereved.

Study design:Retrospective chart review.Objectives:The objective of the study was to analyse the efficacy of single-dose radiation therapy in the treatment of heterotopic ossification (HO) following spinal cord injury (SCI).Setting:Department of Spinal Cord Injury and Department of General and Trauma Surgery, BG-University Hospital Bergmannsheil Bochum, Ruhr-University Bochum, Germany.Methods:Patients who were treated for HO around the hips following SCI at our institution between January 2003 and December 2013 were included in this retrospective cohort study. A total of 444 HO cases around the hip were treated with single-dose radiation therapy after a mean time interval of 4.9 days (0–97 days; s.d.=8.1) after HO diagnosis. Primary outcome measures were the number of HO relapses and the occurrence of adverse side effects related to the radiation therapy.Results:After a mean time interval of 63.2 days (8–295 days; s.d.=39.6) subsequent to SCI HO occurred in 207 male (84.8%) and 37 female (15.2%) patients with a mean age of 46.4 years (18–81 years, s.d.=18.2). In 200 patients both hips were affected, whereas the remaining 44 HO occurred unilateral. None of the patients suffered primary side effects due to the radiation therapy. However, in 13 out of 244 patients (5.3%), HO relapse occurred. After repeated single-dose radiotherapy, one patient suffered joint ankylosis and therefore required surgical resection.Conclusion:Our results present that single-dose radiation therapy is a safe option in the treatment for spinal cord-injured patients suffering from HOs of the hips.Spinal Cord advance online publication, 19 July 2016; doi:10.1038/sc.2016.112. © 2016 International Spinal Cord Society

The concurrent presence or manifestation of multiple chronic conditions, i.e. multimorbidity, poses a challenge to affected patients and their relatives, physicians, and practitioners, and to the health care system in general. Aiming to improve medical care for different chronic diseases, the Chronic Care Model also appears to be suited for multimorbidity. The established research consortium PRISCUS is trying to create some of the prerequisites for a new care model for multimorbid, elderly patients oriented along the lines of the Chronic Care Model. Four out of seven subprojects of the research consortium provide an overview of some of their findings. Topics in a sports medicine subproject were the assessment of physical activity by means of a newly developed questionnaire and the development and feasibility testing of an exercise program for elderly people with chronic conditions and mobility impairment. Partners from family medicine implemented geriatric assessment in a primary care setting and evaluated its consequences. In a pharmacological subproject, potentially inappropriate medication as well as drug-drug interactions and dosing errors were addressed. The health economic subproject investigated quality of life impairment due to multiple chronic diseases and the effects of multimorbidity on costs. The results of the PRISCUS research consortium allow a better description of consequences of multimorbidity and illustrate at least some new approaches towards prevention, diagnosis, and treatment of patients suffering from multimorbidity. Ongoing projects will test the efficacy of a physical activity program and a new complex intervention to reduce potentially inappropriate medication in the elderly. With this, the research consortium will create some prerequisites for a new health care model for patients with multimorbidity comparable to the Chronic Care Model.

In the medium term, European energy policy is aiming at low-emission energy supply with solar-based energy playing a main part. Solar updraft power plants are one option, the concept of which is being outlined. A mathematical model of a solar updraft power plant is presented and the resulting simulation program is scaled with a pilot plant. Besides, studies about optimised electricity generation carried out at two plant sizes are presented. The studies demonstrate the concept's economic efficiency.

Zipp F.,Johannes Gutenberg University Mainz | Gold R.,Ruhr University Bochum | Wiendl H.,University of Munster
JAMA Neurology | Year: 2013

IMPORTANCE: Although multiple sclerosis (MS) has long been considered the prototype for an inflammatory, demyelinating disease of the central nervous system, modern histopathology and imaging techniques show that significant damage to neuronal structures already start occurring in the earliest stages of the disease. As the disease progresses, the extent of neuronal pathology accumulates. Therapeutic progress in terms of the prevention of increased disability has only just begun. OBJECTIVE: To review possible diagnostic improvements of neuronal compartment pathology as well as direct therapeutic interventions based on reports from the last decade and outline clinical results from studies and perspectives on the progression of MS. EVIDENCE REVIEW: Literature search focused on publications and the references contained therein, relating to neuronal compartment pathology and direct therapeutic interventions published in the last decade in well-established peer-reviewed journals. The quality of the cited works was ensured by their acceptance by peer review, participation in clinical trials, and authors' own expert assessment. FINDINGS: Current MS therapies aswell as medications that are in late phase 3 trials or under approval exhibit primarily anti-inflammatory properties. However, clinical and imaging data demonstrate the potential of using novel therapies to prevent neuronal damage. Whether these exhibit effects on the neuronal compartment due to interference with the immune system or additional direct effects depends without question on the specific mechanism of action. CONCLUSIONS AND RELEVANCE: Combining anti-inflammatory and direct neuroprotective, neuroregenerative/ repair therapy strategiesmay open up new avenues in the treatment of MS. Copyright 2013 American Medical Association. All rights reserved.

Korfel A.,Franklin University | Schlegel U.,Ruhr University Bochum
Nature Reviews Neurology | Year: 2013

Primary CNS lymphoma (PCNSL) is a rare lymphoma that is confined to the CNS, with low tendency for systemic dissemination and a relatively aggressive course. Outcome in patients with PCNSL is often poor. Owing to its low incidence, current knowledge about optimal treatment of PCNSL is fragmentary. Chemotherapy regimens based on high-dose methotrexate are currently standard treatment for all patients with PCNSL who can tolerate such drugs. Whole-brain radiotherapy alone can lead to remission in up to 90% of patients, but often results in poor long-term disease control when given alone, and in delayed neurotoxicity when given after high-dose methotrexate. In this Review, we describe current approaches to diagnosis and treatment of PCNSL, and discuss novel therapeutic approaches that are currently in development, such as the use of rituximab and high-dose chemotherapy followed by autologous stem-cell transplantation. The possible use of intrathecal and intraventricular chemotherapy, optimal salvage treatment, and specific treatment approaches in elderly, paediatric and immunocompromised patients, are also considered. © 2013 Macmillan Publishers Limited. All rights reserved.

Dickmann F.,Ruhr University Bochum
Cartographic Journal | Year: 2010

Lenticular visualisation methods are innovative advancements of modern presentation media in cartography. Owing to the mainly three-dimensional perception of people, this technique, in print as well as on screen, offers the possibility to introduce autostereoscopic, i.e. three-dimensional views in cartography. On the basis of true 3D, it has already found its way into the visualisation of relief relations. Moreover, it also opens perspectives for the more widespread products of thematic cartography (thematic maps). Multi-layered representation becomes possible on the basis of three-dimensional or sequentially differentiated depictions of spatial phenomena. Thus, several parameters or dimensions of cartographic content can be displayed at the same time. This essay discusses some potential applications of the lenticular foil technique for thematic cartography on a theoretical basis. © The British Cartographic Society 2010.

Schildmann E.K.,Ludwig Maximilians University of Munich | Schildmann J.,Ruhr University Bochum | Kiesewetter I.,Ludwig Maximilians University of Munich
Journal of Pain and Symptom Management | Year: 2015

Context Palliative sedation therapy (PST) is increasingly used in patients at the end of life. However, consensus about medications and monitoring is lacking. Objectives To assess published PST guidelines with regard to quality and recommendations on drugs and monitoring. Methods We searched CINAHL, the Cochrane Library, Embase, PsycINFO, PubMed, and references of included articles until July 2014. Search terms included "palliative sedation" or "sedation" and "guideline" or "policy" or "framework." Guideline selection was based on English or German publications that included a PST guideline. Two investigators independently assessed the quality of the guidelines according to the Appraisal of Guidelines for Research and Evaluation II instrument (AGREE II) and extracted information on drug selection and monitoring. Results Nine guidelines were eligible. Eight guidelines received high quality scores for the domain "scope and purpose" (median 69%, range 28-83%), whereas in the other domains the guidelines' quality differed considerably. The majority of guidelines suggest midazolam as drug of first choice. Recommendations on dosage and alternatives vary. The guidelines' recommendations regarding monitoring of PST show wide variation in the number and details of outcome parameters and methods of assessment. Conclusion The published guidelines on PST vary considerably regarding their quality and content on drugs and monitoring. Given the need for clear guidance regarding PST in patients at the end of life, this comparative analysis may serve as a starting point for further improvement. © 2015 American Academy of Hospice and Palliative Medicine.

Ludwig A.,Ruhr University Bochum
Nature Nanotechnology | Year: 2016

Transporting ensembles of electrons over long distances without losing their spin polarization is an important benchmark for spintronic devices. It usually requires injecting and probing spin-polarized electrons in conduction channels using ferromagnetic contacts or optical excitation. In parallel with this development, important efforts have been dedicated to achieving control of nanocircuits at the single-electron level. The detection and coherent manipulation of the spin of a single electron trapped in a quantum dot are now well established. Combined with the recently demonstrated control of the displacement of individual electrons between two distant quantum dots, these achievements allow the possibility of realizing spintronic protocols at the single-electron level. Here, we demonstrate that spin information carried by one or two electrons can be transferred between two quantum dots separated by a distance of 4 μm with a classical fidelity of 65%. We show that at present it is limited by spin flips occurring during the transfer procedure before and after electron displacement. Being able to encode and control information in the spin degree of freedom of a single electron while it is being transferred over distances of a few micrometres on nanosecond timescales will pave the way towards ‘quantum spintronics’ devices, which could be used to implement large-scale spin-based quantum information processing. © 2016 Nature Publishing Group

Penders J.,Maastricht University | Gerhold K.,Charite - Medical University of Berlin | Stobberingh E.E.,Maastricht University | Thijs C.,Maastricht University | And 3 more authors.
Journal of Allergy and Clinical Immunology | Year: 2013

Background Perturbations in the intestinal microbiota may disrupt mechanisms involved in the development of immunologic tolerance. The present study aimed to examine the establishment of the infant microbiota and its association to the development of atopic dermatitis (AD). Methods Within a randomized, placebo-controlled trial on the prevention of AD by oral supplementation of a bacterial lysate between week 5 and the end of month 7, feces was collected at the ages of 5 weeks (n = 571), 13 weeks (n = 332), and 31 weeks (n = 499) and subjected to quantitative PCRs to detect bifidobacteria, bacteroides, lactobacilli, Escherichia coli, Clostridium difficile, and Clostridium cluster I. Results Birth mode, breast-feeding but also birth order had a strong effect on the microbiota composition. With increasing number of older siblings the colonization rates at age 5 weeks of lactobacilli (P <.001) and bacteroides (P =.02) increased, whereas rates of clostridia decreased (P <.001). Colonization with clostridia, at the age of 5 and 13 weeks was also associated with an increased risk of developing AD in the subsequent 6 months of life (odds ratioadjusted = 2.35; 95% CI, 1.36-3.94 and 2.51; 1.30-4.86, respectively). Mediation analyses demonstrated that there was a statistically significant indirect effect via Clostridium cluster I colonization for both birth mode and birth order in association to AD. Conclusion The results of this study are supportive for a role of the microbiota in the development of AD. Moreover, the "beneficial" influence of older siblings on the microbiota composition suggests that this microbiota may be one of the biological mechanisms underlying the sibling effect. © 2013 American Academy of Allergy, Asthma & Immunology.

Lodes M.A.,Friedrich - Alexander - University, Erlangen - Nuremberg | Hartmaier A.,Ruhr University Bochum | Goken M.,Friedrich - Alexander - University, Erlangen - Nuremberg | Durst K.,Friedrich - Alexander - University, Erlangen - Nuremberg
Acta Materialia | Year: 2011

In this work, the indentation size effect and pop-in behavior are studied for indentations in undeformed and locally pre-deformed CaF2 single crystals, using both nanoindentation experiments and molecular dynamics simulations. To study the influence of dislocation density on the indentation behavior, small-scale indentations are carried out inside the plastic zone of larger indentations. This experiment is mimicked in the simulations by indenting a small sphere into the center of the residual impression of a larger sphere. The undeformed material shows the well-known pop-in behavior followed by the indentation size effect. Pre-deforming the material leads to a reduction in the indentation size effect both for experiments and simulations, which is in accordance with the Nix-Gao theory. Furthermore, the pop-in load is reduced in the experiments, whereas a smooth transition from elastic to plastic deformation is found in the simulations. There, plasticity is initiated by the movement of pre-existing dislocation loops in the vicinity of the plastic zone. The simulations thus give a detailed insight into the deformation mechanism during indentation and highlight the importance of the dislocation microstructure for the indentation size effect and dislocation nucleation. © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Mendonca J.T.,University of Lisbon | Shukla P.K.,Ruhr University Bochum
Physics of Plasmas | Year: 2011

We consider the excitation and dispersion of electrostatic ion-acoustic (IA) waves in a nonstationary ultra-cold neutral plasma (UCNP). This can be seen as an extension of time-refraction models of photons and plasmons to the case of low-frequency IA waves in the UCNP. It is shown that temporal changes in the medium lead to a frequency-shift of the IA wave, and to the emission of the IA waves propagating in a direction opposite to each other. We consider an arbitrary temporal variation of the background plasma density, and determine the transmission and reflection coefficients. We also consider the influence of a fast ionization process, assumed inhomogeneous in volume and show that it excites a well-defined spectrum of ion-acoustic waves, which agree very well with a recent experimental observation. © 2011 American Institute of Physics.

Moslem W.M.,Port Said University | Moslem W.M.,Ruhr University Bochum
Physics of Plasmas | Year: 2011

Progress in understanding the nonlinear Langmuir rogue waves which accompany collisionless electron-positron (e-p) plasmas is presented. The nonlinearity of the system results from the nonlinear coupling between small, but finite, amplitude Langmuir waves and quasistationary density perturbations in an e-p plasma. The nonlinear Schrödinger equation is derived for the Langmuir waves' electric field envelope, accounting for small, but finite, amplitude quasistationary plasma slow motion describing the Langmuir waves' ponderomotive force. Numerical calculations reveal that the rogue structures strongly depend on the electron/positron density and temperature, as well as the group velocity of the envelope wave. The present study might be helpful to understand the excitation of nonlinear rogue pulses in astrophysical environments, such as in active galactic nuclei, in pulsar magnetospheres, in neutron stars, etc. © 2011 American Institute of Physics.

Behr J.,Ruhr University Bochum
Clinics in Chest Medicine | Year: 2012

Interstitial lung diseases (ILDs) encompass a wide range of diffuse pulmonary disorders, characterized by a variable degree of inflammatory and fibrotic changes of the alveolar wall and eventually the distal bronchiolar airspaces. ILDs may occur in isolation or in association with systemic diseases. The clinical evaluation of a patient with ILD includes a thorough medical history and detailed physical examination; obligatory diagnostic testing includes laboratory testing, chest radiography, and high-resolution computed tomography and comprehensive pulmonary function testing and blood gas analysis. To optimize the diagnostic yield, a dynamic interaction between the pulmonologist, radiologist, and pathologist is mandatory. © 2012 Elsevier Inc.

Nauck M.A.,Diabeteszentrum Bad Lauterberg | Baranov O.,Diabeteszentrum Bad Lauterberg | Ritzel R.A.,Diabetes and Nuclear Medicine | Meier J.J.,Ruhr University Bochum
Diabetologia | Year: 2013

Glucagon-like peptide-1 (GLP-1) receptor agonists (RAs) are incretin-derived glucose-lowering agents that have been used for the treatment of type 2 diabetes since 2007. Agents such as exenatide (short-acting and once weekly preparations), liraglutide, taspoglutide, albiglutide and lixisenatide lower fasting glucose and HbA1c upon subcutaneous injection, leading to glycaemic control that is equivalent to, or better than, that observed with other oral glucose-lowering agents or bedtime insulin. However, varying proportions of patients report nausea and vomiting, adverse events that typically narrow the therapeutic dose range. Furthermore, GLP-1 RAs reduce fasting glucose to a clinically meaningful extent, but not into the normal range. In contrast, where GLP-1 is administered as a short-term intravenous infusion, a full normalisation of glucose concentrations (approximately 5 mmol/l) has been observed without any risk of gastrointestinal side effects. Subcutaneous infusions or injections of GLP-1 are much less effective. The present analysis relates the proportion of patients who report nausea following treatment with GLP-1 and GLP-1 RAs to the clinical effectiveness of the treatment (represented by the fasting glucose concentration achieved with treatment). The results suggest that GLP-1 RAs injected into the subcutaneous compartment do not exploit the full potential inherent in GLP-1 receptor activation. Reasons for this may include modifications of the peptide molecules in the subcutaneous environment or high local concentrations triggering side effects through GLP-1 receptors on autonomic nerves in subcutaneous adipose tissue. Elucidation of the mechanisms underlying differential responses to GLP-1/GLP-1 RAs administered intravenously vs subcutaneously may help to develop improved agents or modes of administration that are more effective and have fewer side effects. © 2013 Springer-Verlag Berlin Heidelberg.

Ochs K.,Ruhr University Bochum
European Journal of Physics | Year: 2011

In this paper, an analytical solution for the differential equation of the simple but nonlinear pendulum is derived. This solution is valid for any time and is not limited to any special initial instance or initial values. Moreover, this solution holds if the pendulum swings over or not. The method of approach is based on JACOBI elliptic functions and starts with the solution of a pendulum that swings over. Due to a meticulous sign correction term, this solution is also valid if the pendulum does not swing over. © 2011 IOP Publishing Ltd.

Wieland U.,University of Cologne | Kreuter A.,Ruhr University Bochum
Current Opinion in Oncology | Year: 2011

Purpose of Review: Merkel cell polyomavirus (MCPyV) was recently discovered in Merkel cell carcinoma (MCC), an aggressive nonmelanoma skin tumour. MCC incidence has been rising in the last decades. Immunocompromised individuals such as HIV-infected patients have an increased risk for MCC development. Recent Findings: MCPyV is found-mostly integrated into the host genome-in approximately 80% of MCC. The causal role of MCPyV in MCC development has been corroborated by several recent studies. Cutaneous MCPyV infection is acquired early in life and is widespread in the general population. In HIV-positive patients, MCPyV-DNA has been detected on the skin, on oral and anogenital mucosa, and in plucked eyebrow-hairs. Compared with healthy controls, MCPyV prevalence is increased in HIV-infected individuals and severe HIV-related immunosuppression is associated with elevated cutaneous MCPyV-DNA loads. This could explain the increased MCC risk found in HIV-infected individuals. MCC in HIV-infected patients occurs at a relatively young age and frequently on sites not exposed to sunlight. Summary: Guidelines for screening and early detection of MCC should be developed for HIV-positive patients. Future studies should evaluate changes in MCC incidence rates in HIV-infected individuals and analyse the effect of immune restoration by (early) antiretroviral therapy on MCC incidence and on cutaneous MCPyV load. © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins.

Herrmann M.,Ruhr University Bochum
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2011

In this paper we investigate the Multi-Prime φ-Hiding Problem as introduced in a recent construction by Kiltz et al. from Crypto 2010. We are able to improve upon previous cryptanalytic results by making use of the special structure of the polynomial that is derived from the problem instance. Our attack is based on the method of Coppersmith for finding small solutions of modular equations. In particular, we make use of a recent result from Herrmann and May to solve linear equations modulo divisors. © 2011 Springer-Verlag.

Wrobel J.M.,U.S. National Radio Astronomy Observatory | Comerford J.M.,University of Colorado at Boulder | Middelberg E.,Ruhr University Bochum
Astrophysical Journal | Year: 2014

COSMOS J100043.15+020637.2 is a merger remnant at z = 0.36 with two optical nuclei, NW and SE, offset by 500 mas (2.5 kpc). Prior studies suggest two competing scenarios for these nuclei: (1) SE is an active galactic nucleus (AGN) lost from NW due to a gravitational-wave recoil. (2) NW and SE each contain an AGN, signaling a gravitational-slingshot recoil or inspiralling AGNs. We present new images from the Very Large Array (VLA) at a frequency ν = 9.0 GHz and a FWHM resolution θ = 320 mas (1.6 kpc), and the Very Long Baseline Array (VLBA) at ν = 1.52 GHz and θ = 15 mas (75 pc). The VLA imaging is sensitive to emission driven by AGNs and/or star formation, while the VLBA imaging is sensitive only to AGN-driven emission. No radio emission is detected at these frequencies. Folding in prior results, we find: (a) The properties of SE and its adjacent X-ray feature resemble those of the Type 1 AGN in NGC 4151, albeit with a much higher narrow emission-line luminosity. (b) The properties of NW are consistent with it hosting a Compton-thick AGN that warms ambient dust, photoionizes narrow emission-line gas, and is free-free absorbed by that gas. Finding (a) is consistent with scenarios (a) and (b). Finding (b) weakens the case for scenario (a) and strengthens the case for scenario (b). Follow-up observations are suggested. © 2014. The American Astronomical Society. All rights reserved..

Heyse S.,Ruhr University Bochum
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2011

Most public-key cryptosystems frequently implemented have been proven secure on the basis of the presumed hardness of two mathematical problems: factoring the product of two large primes (FP) and computing discrete logarithms (DLP). At present, both problems are believed to be computationally infeasible with an ordinary computer. However, a quantum-computer having the ability to perform computations on a few thousand qbits could solve both problems using Shor's algorithm [23]. Although a quantum computer of this dimension has not been reported, development and cryptanalysis of alternative public-key cryptosystems seem suitable. To achieve acceptance and attention in practice, they have to be implemented efficiently. Furthermore, the implementations have to perform fast while keeping memory requirements low for security levels comparable to conventional schemes. The McEliece encryption and decryption do not require computationally expensive multiple precision arithmetic. Hence, it is predestined for an implementation on embedded devices. The major disadvantage of the McEliece public-key cryptosystem(PKC) is its very large public key of several hundred thousands bits. For this reason, the McEliece PKC has achieved little attention in the practice. Another disadvantage of the McEliece scheme, like many other schemes, is that it is not semantically secure. The quasi-dyadic McEliece variant proposed by Barreto and Misoczki addresses both problems. In this work we provide an implementation of this alternative public-key cryptosystem, which is semantically secure and uses a 40 times smaller public key and a five times smaller secret key compared to a previously published implementation [6]. © 2011 Springer-Verlag.

Rosenkranz K.,Ruhr University Bochum | Meier C.,Saarland University
Annals of Anatomy | Year: 2011

Cell transplantation has been proposed as a potential approach to the treatment of neurological disorders. One cell population of interest consists of human umbilical cord blood (hUCB) cells, which have previously been shown to be useful for reparative medicine in haematological diseases. However, hUCB cells are also capable of differentiating into various non-haematopoietic cells, including those of the neural lineage. Moreover, hUCB cells can secrete numerous neurotrophic factors and modulate immune function and inflammatory reaction. Several studies on animal models of ischemic brain injury have demonstrated the potential of hUCB cells to minimize damage and promote recovery after ischemic brain injury. This review focuses on the treatment of both stroke and perinatal hypoxic-ischemic brain injury using hUCB cells. We discuss the therapeutic effects demonstrated after hUCB cell transplantation and emphasize possible mechanisms counteracting pathophysiological events of ischemia, thus leading to the generation of a regenerative environment that allows neural plasticity and functional recovery. The therapeutic functional effects of hUCB cells observed in animal models make the transplantation of hUCB cells a promising experimental approach in the treatment of ischemic brain injury. Together with its availability, low risk of transplantation, immaturity of cells, and simple route of application, hUCB transplantation may stand a good chance of being translated into a clinical setting for the therapy of ischemic brain injury. © 2011 Elsevier GmbH.

Henzl J.,Leibniz University of Hanover | Boom K.,Leibniz University of Hanover | Morgenstern K.,Ruhr University Bochum
Journal of the American Chemical Society | Year: 2014

Determination of the exact structure of individual molecules is the ultimate goal of high-resolution microscopy. However, the resolution of scanning tunneling microscopy (STM) is intrinsically limited to the extent of molecular orbitals, which frequently do not differ for small changes in the molecular conformation. Here we use the position of water molecules during the first hydration steps of an azobenzene derivative on Au(111) to determine not only the orientation of the end groups with respect to the phenyl rings but also the orientation of the two phenyl rings with respect to the azo group. We investigate the co-adsorption of 4,4'-hydroxy-azobenzene and water molecules on Au(111) by low-temperature STM. The water molecules are attached exclusively to the hydroxyl end groups of the azobenzene derivatives. Predominantly the trans-azobenzene molecule with the two hydroxyl groups pointing into opposite directions is adsorbed. As corroborated by the attachment of a single water molecule to 4-anilino-4?-nitro azobenzene on the same inert surface, the method is generally applicable for structure determination of molecules with appropriate end groups. Our study thus gives unprecedented information about the intramolecular orientation based on the first real space observation of the hydration of a functional molecule. © 2014 American Chemical Society.

Several disease-modifying therapies are approved for the management of multiple sclerosis (MS). While reasonably effective, these therapies require long-term parenteral self-injection, which is inconvenient for some patients and can be associated with injection-related adverse effects. Consequently, there is a need in MS for an oral therapy option. Currently, five oral therapies are in phase III development or have recently been approved for the treatment of relapsing-remitting MS: cladribine (approved in Russia and Australia), fingolimod (approved in the US and Russia), BG-12 (phase III), laquinimod (phase III) and teriflunomide (phase III). While the availability of oral therapies has been much anticipated by physicians and patients, neurologists will need to be cautious in selecting such therapy, which may appear to have efficacy and convenience advantages versus current therapies, but may also carry novel safety and tolerability concerns. The decision to use these new therapies will most likely be based on an overall assessment of efficacy, safety, tolerability and adherence, the potential need for monitoring and cost effectiveness.The objective of this article is to review the currently available data for each of these new oral therapies, which addresses the mechanism of action, efficacy and safety, and to provide a perspective on the potential future role of these therapies within clinical practice. Although better patient compliance is expected with the oral agents compared with the injectables, the safety profiles of these new oral drugs will have to be watched carefully. © 2011 Adis Data Information BV. All rights reserved.

Stefanis N.G.,Ruhr University Bochum | Bakulev A.P.,Joint Institute for Nuclear Research | Mikhailov S.V.,Joint Institute for Nuclear Research | Pimikov A.V.,University of Valencia
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013

A state-of-the-art analysis of the pion-photon transition form factor is presented based on an improved theoretical calculation that includes the effect of a finite virtuality of the quasireal photon in the method of light-cone sum rules. We carry out a detailed statistical analysis of the existing experimental data using this method and by employing pion distribution amplitudes with up to three Gegenbauer coefficients a2, a4, a6. Allowing for an error range in the coefficient a6≈0, the theoretical predictions for γ*γ→π0 obtained with nonlocal QCD sum rules are found to be in good agreement with all data that support a scaling behavior of the transition form factor at higher Q2, like those of the Belle Collaboration. The data on γ *γ→η/η′ from CLEO and BABAR are also reproduced, while there is a strong conflict with the auxetic trend of the BABAR data above 10 GeV2. The broader implications of these findings are discussed. © 2013 American Physical Society.

Schertl H.-P.,Ruhr University Bochum | O'Brien P.J.,University of Potsdam
Elements | Year: 2013

Finding evidence for ultrahigh-pressure (UHP) metamorphism in crustal rocks is far from straightforward. The index minerals coesite and diamond are incredibly inconspicuous and are therefore difficult to use as UHP prospecting tools. Consequently, petrographers rely on recognizing subtle breakdown microstructures that result from pressure release during the return to the surface of the once deeply buried rock. Similarly, many other UHP minerals are first suspected on the basis of typical reaction or exsolution microstructures. Thus, the painstaking use of microscopic techniques has been fundamental to the tremendous advances in characterizing, quantifying, and understanding macroscopic-scale, deep continental subduction, rapid exhumation, and mountain-building processes.

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.

Drautz R.,Ruhr University Bochum | Pettifor D.G.,University of Oxford
Physical Review B - Condensed Matter and Materials Physics | Year: 2011

We extend the analytic bond-order potentials for transition metals to include ferro, antiferro, and noncollinear magnetism and charge transfer. This is achieved by first deriving a suitable tight-binding model through the expansion of the spin-density energy functional to second order with respect to magnetic and charge fluctuations. The tight-binding model is then approximated locally by the bond-order potential expansion, where the variational property of the bond-order potential expansion allows us to derive analytic expressions for the forces and torques on the atoms. From the bond-order potentials we then extract a hierarchy of multispin interactions beyond the conventional Heisenberg model. The explicit valence dependence of the bond-order potentials enables us to characterize the magnetic properties of the 3d transition metals and to reproduce the trend from antiferromagnetic spin ordering close to the center of the d band through noncollinear spin configurations to ferromagnetic ordering toward the edges of the d band. The analytic representation of the energy within the bond-order potentials is then further expanded in the form of a Ginzburg-Landau expansion, deriving the prefactors explicitly from tight-binding and bond-order potentials. Thus, in this paper we present a coherent simplification from fundamental to empirical models of magnetism through coarse graining the electronic structure from spin-density functional theory to tight binding to bond-order potentials to the Ginzburg-Landau expansion. © 2011 American Physical Society.

Behler J.,Ruhr University Bochum
Physical Chemistry Chemical Physics | Year: 2011

The accuracy of the results obtained in molecular dynamics or Monte Carlo simulations crucially depends on a reliable description of the atomic interactions. A large variety of efficient potentials has been proposed in the literature, but often the optimum functional form is difficult to find and strongly depends on the particular system. In recent years, artificial neural networks (NN) have become a promising new method to construct potentials for a wide range of systems. They offer a number of advantages: they are very general and applicable to systems as different as small molecules, semiconductors and metals; they are numerically very accurate and fast to evaluate; and they can be constructed using any electronic structure method. Significant progress has been made in recent years and a number of successful applications demonstrate the capabilities of neural network potentials. In this Perspective, the current status of NN potentials is reviewed, and their advantages and limitations are discussed. © the Owner Societies 2011.

Harbo H.F.,University of Oslo | Gold R.,Ruhr University Bochum | Tintore M.,Autonomous University of Barcelona
Therapeutic Advances in Neurological Disorders | Year: 2013

Multiple sclerosis (MS) is universally found to be more prevalent in women than men. This has led to extensive studies of differences in the immune system or nervous system between women and men, which might be caused by the effects of gonadal hormones, genetic differences, and different environmental exposures and modern lifestyle in men and women. We review the effects of sex and gender from a genetic, immunological and clinical point of view. We discuss the effects of sex on the clinical expression of MS and responses to therapy, as well as issues concerning pregnancy. © The Author(s), 2013.

The task of synchronisation of autonomous agents can be solved by a networked controller that steers the agents towards a common trajectory. This paper proves a condition for the synchronism that makes it possible to decompose the design task into two steps. First, the stability region of the agents are to be determined, for which in the second step a networked controller should be found. The main result is a necessary and sufficient condition for the agents to possess the synchronisability property. The results are illustrated by its application to a string of vehicles. © Oldenbourg Wissenschaftsverlag.

Bleier N.,Ruhr University Bochum | Mosler J.,Helmholtz Center Geesthacht
International Journal for Numerical Methods in Engineering | Year: 2012

Analogously to the classical return-mapping algorithm, so-called variational constitutive updates are numerical methods allowing to compute the unknown state variables such as the plastic strains and the stresses for material models showing an irreversible mechanical response. In sharp contrast to standard approaches in computational inelasticity, the state variables follow naturally and jointly from energy minimization in case of variational constitutive updates. This leads to significant advantages from a numerical, mathematical as well as from a physical point of view. However, while the classical return-mapping algorithm has been being developed for several decades, and thus, it has already reached a certain maturity, variational constitutive updates have drawn attention only relatively recently. This is particularly manifested in the numerical performance of such algorithms. Within the present paper, the numerical efficiency of variational constitutive updates is critically analyzed. It will be shown that a naive approximation of the flow rule causes a singular Hessian within the respective Newton-Raphson scheme. However, by developing a novel parameterization of the flow rule, an efficient algorithm is derived. Its performance is carefully compared to that of the classical return-mapping scheme. This comparison clearly shows that the novel variationally consistent implementation is, at least, as efficient as the classical return-mapping algorithm. © 2011 John Wiley & Sons, Ltd.

Brown E.C.,Ruhr University Bochum
Expert review of neurotherapeutics | Year: 2012

Therapeutic strategies for improving social cognition in patients with schizophrenia have shown much promise in improving social functioning, as well as remediating core psychotic symptoms. However, the efficacy of previous interventions has often been limited by the ambiguity and inconsistency of the categorized subdomains of social cognition, including theory of mind, emotion processing, social perception and attributional bias. Recent research in social and cognitive neuroscience has revealed many new issues that could contribute to the development of more integrated approaches for improving social functioning. The application of such neuroscientific work to a therapeutic and diagnostic context is likely to encourage more effective transference of learned skills to real-world social functioning. This article seeks to provide a comprehensive review of previous social cognitive interventions for schizophrenia, highlight some crucial limitations of these and present the relevance of recent advances in neuroscientific research in possible future treatment strategies. It is emphasized that a more integrated and naturalistic approach for improving social functioning with greater sensitivity for neuroscientific findings related to the psychopathology of schizophrenia is warranted.

Lunze J.,Ruhr University Bochum
Asian Journal of Control | Year: 2014

The paper deals with the synchronisation of subsystems that have individual linear dynamics. To formulate the basic condition under which the subsystems can be synchronised, the notion of system intersection is introduced. Subsystems can be synchronised by an appropriate controller only if their dynamics have a non-empty intersection, which acts as a virtual reference system. The paper describes an algorithm for determining the maximum intersection of linear systems and gives an explicit relation for the initial state in dependence upon the subsystem initial states, for which the virtual reference system generates the synchronous trajectory. © 2013 Chinese Automatic Control Society and Wiley Publishing Asia Pty Ltd.

Kirmse W.,Ruhr University Bochum
Angewandte Chemie - International Edition | Year: 2010

A long time in the waiting: In 1960 Wanzlick brought N-heterocyclic carbenes to the point of take off. Experimental shortcomings, misunderstanding, and prejudgments, however, hindered their take off. Only 30 years later, with the isolation and structural elucidation of N-heterocyclic carbenes by Arduengo, did the flight begin. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Hinrichs T.,Ruhr University Bochum | Brach M.,University of Munster
Current Aging Science | Year: 2012

Positive influences of physical activity both on many chronic diseases and on preservation of mobility are well documented. But chronically ill or mobility restricted elderly living in their own homes are difficult to reach for interventions. The general practitioner's (GP) surgery offers one of the few opportunities to give advice for physical activity to those people. We used program theory to sound out knowledge on GP-centered physical activity counseling. The "conceptual theory" (evidence for training effects in old age) and the "implementation theory" (unique position of the GP) were reviewed narratively. The "action theory" (effects of GP counseling) was reviewed systematically. According to program theory, appropriate MeSH (Medical subject headings) concepts were Aged OR Aged, 80 and over (Target group), Physicians, Family OR Primary Health Care (Implementation/Setting), Counseling OR Patient Education as Topic OR Disease Management OR Health promotion (Intervention), Exercise OR Motor Activity OR Physical Fitness OR Sports (Determinants). The resulting six review papers (Pubmed, 2000-2009) were presented using the STARLITE mnemonic. Authors agree, that the GP plays a central role in the promotion of physical activity to elderly people, but there is conflicting evidence concerning counseling effectiveness. Utilizing behavioral change strategies and the collaboration between GPs and specialised professions are recommended and currently under research. © 2012 Bentham Science Publishers.

Grehl T.,Ruhr University Bochum
Quality of life research : an international journal of quality of life aspects of treatment, care and rehabilitation | Year: 2011

Amyotrophic lateral sclerosis (ALS) is a lethal neurodegenerative disease affecting the motor nervous system and currently lacking effective means of treatment. The focus of ALS treatment therefore lies in palliative treatment from a multidisciplinary team. Published findings regarding affective components and patients' perceived quality-of-life (QoL) as well as comparative reports of family members/caregivers remain equivocal. In this study, 41 ALS patients and their relatives were enrolled in a study employing the 12-item ALS-Depression-Inventory (ADI-12) and the Munich quality-of-life dimensions list (MLDL). The ALS-functional rating scale (ALSFRS-R) was used to evaluate physical disabilities. The ADI-12 depression scale data identified nine patients with depressive disorders; the patients had satisfactory QoL outcomes on the MLDL. The results did not differ significantly between ALS patients and their relatives. Thus, in agreement with other studies, QoL and emerging depression do not automatically coincide with patients' physical impairments of the patients. This "well-being paradox" is currently not well understood, and further studies are needed to optimize the treatment of patients through the course of disease progression.

Metzler-Nolte N.,Ruhr University Bochum
Topics in Organometallic Chemistry | Year: 2010

Peptides are well suited as targeting vectors for the directed delivery of metal-based drugs or probes for biomedical investigations. This chapter describes synthetic strategies for the preparation of conjugates of medically interesting peptides with covalently bound metal complexes. Peptides that were used include neuropeptides (enkephalin, neuropeptide Y, neurotensin), uptake peptides (TAT and poly-Arg), and intracellular localization sequences. To these peptides, a whole variety of transition metal complexes has been attached in recent years by solid-phase peptide synthesis (SPPS) techniques. The metal complex can be attached to the peptide on the resin as part of the SPPS scheme. Alternatively, the metal complex may be attached to the peptide as a postsynthetic modification. Advantages as well as disadvantages for either strategy are discussed. Biomedical applications include radiopharmaceutical applications, anticancer and antibacterial activity, metal-peptide conjugates as targeted CO-releasing molecules, and metal-peptide conjugates in biosensor applications. © 2010 Springer-Verlag Berlin Heidelberg.

Richter J.H.,Siemens AG | Heemels W.P.M.H.,TU Eindhoven | Van De Wouw N.,TU Eindhoven | Lunze J.,Ruhr University Bochum
Automatica | Year: 2011

A reconfigurable control approach for continuous-time piecewise affine (PWA) systems subject to actuator and sensor faults is presented. The approach extends the concept of virtual actuators and virtual sensors from linear to PWA systems on the basis of the fault-hiding principle that provides the underlying conceptual idea: the fault is hidden from the nominal controller and the fault effects are compensated. Sufficient linear matrix inequality (LMI) conditions for the existence of virtual actuators and virtual sensors are given that guarantee the recovery of closed-loop stability and the tracking of constant reference inputs. Since LMIs are efficiently solvable, this solution leads to a tractable computational algorithm that solves the reconfiguration problem. The approach is proven to be robust against model uncertainties and inaccurate fault diagnosis, and is evaluated using an example system of interconnected tanks. © 2011 Elsevier Ltd. All rights reserved.

Meule A.,University of Wurzburg | Meule A.,Ruhr University Bochum | Kubler A.,University of Wurzburg
Appetite | Year: 2014

Impulsivity and food craving have both been implicated in overeating. Recent results suggest that both processes may interactively predict increased food intake. In the present study, female participants performed a Go/No-go task with pictures of high- and low-calorie foods. They were instructed to press a button in response to the respective target category, but withhold responses to the other category. Target category was switched after every other block, thereby creating blocks in which stimulus-response mapping was the same as in the previous block (nonshift blocks) and blocks in which it was reversed (shift blocks). The Food Cravings Questionnaires and the Barratt Impulsiveness Scale were used to assess trait and state food craving and attentional, motor, and nonplanning impulsivity. Participants had slower reaction times and more omission errors (OE) in high-calorie than in low-calorie blocks. Number of commission errors (CE) and OE was higher in shift blocks than in nonshift blocks. Trait impulsivity was positively correlated with CE in shift blocks while trait food craving was positively correlated with CE in high-calorie blocks. Importantly, CE in high-calorie-shift blocks were predicted by an interaction of food craving×impulsivity such that the relationship between food craving and CE was particularly strong at high levels of impulsivity, but vanished at low levels of impulsivity. Thus, impulsive reactions to high-calorie food-cues are particularly pronounced when both trait impulsivity and food craving is high, but low levels of impulsivity can compensate for high levels of trait food craving. Results support models of self-regulation which assume that interactive effects of low top-down control and strong reward sensitive, bottom-up mechanisms may determine eating-related disinhibition, ultimately leading to increased food intake. © 2014 Elsevier Ltd.

Stefanis N.G.,Ruhr University Bochum
Few-Body Systems | Year: 2012

An analysis of all available data (CELLO, CLEO, BABAR) in the range [1÷ 40] GeV 2 for the pion-photon transition form factor in terms of light-cone sum rules with next-to-leading-order accuracy is discussed, including twist-four contributions and next-to-next-to-leading order and twist-six corrections-the latter two via uncertainties. The antithetic trend between the BABAR data for the γ*γπ 0 and those for the γ*γη(η′) transition is pointed out, emphasizing the underlying antagonistic mechanisms: endpoint enhancement for the first and endpoint-suppression for the second-each associated with pseudoscalar meson distribution amplitudes with distinct endpoint characteristics. © 2011 Springer-Verlag.

In this century, biofuels will play an important role as fossil fuel alternatives. However, the long-term sustainability of large-scale biomass-based energy production chains is largely unknown. The current study evaluates the effect of nitrogen and phosphorus nutrient recovery on net energy ratio (NER) and land use, comparing a prospective industrial-scale microalgae production system with established maize agriculture. The functional unit was the delivery of 1.0 TWh of electrical energy using biomethane firing. Nutrient recovery was modeled by embedding anaerobic digestion (AD) as downstream processing step in the biomass production chains. The main finding was that maize-based biomethane electricity provision outperforms a prospective microalgae system in terms of NER, estimated at 4.9 and 3.2, respectively, when utilizing cogenerated heat. In the absence of external fossil fuel input, the renewable maize- and microalgae-based systems would require surface areas of 6.2 × 10 4 and 3.9 × 10 4 ha, respectively. Sustainability of microalgae-based biofuel production is not set by areal productivity or microalgal lipid content but rather by nutrient recovery, which is an important finding that requires prioritization in microalgae research. © 2012 American Chemical Society.

Kuss O.,Martin Luther University of Halle Wittenberg | Von Salviati B.,Martin Luther University of Halle Wittenberg | Borgermann J.,Ruhr University Bochum
Journal of Thoracic and Cardiovascular Surgery | Year: 2010

Objective: Despite numerous randomized and nonrandomized trials on off- and on-pump coronary artery bypass grafting, it remains open which method is superior. Patient selection and small sample sizes limit the evidence from randomized trials; lack of randomization limits the evidence from nonrandomized trials. Propensity score analyses are expected to improve on at least some of these problems. We aimed to systematically review all propensity score analyses comparing off- and on-pump coronary artery bypass grafting. Methods: Propensity score analyses comparing off- and on-pump surgery were identified from 8 bibliographic databases, citation tracking, and a free web search. Two independent reviewers abstracted data on 11 binary short-term outcomes. Results: A total of 35 of 58 initially retrieved propensity score analyses were included, accounting for a total of 123,137 patients. The estimated overall odds ratio was less than 1 for all outcomes, favoring off-pump surgery. This benefit was statistically significant for mortality (odds ratio, 0.69; 95% confidence interval, 0.60-0.75), stroke, renal failure, red blood cell transfusion (P < .0001), wound infection (P < .001), prolonged ventilation (P < .01), inotropic support (P = .02), and intraaortic balloon pump support (P = .05). The odds ratios for myocardial infarction, atrial fibrillation, and reoperation for bleeding were not significant. Conclusions: Our systematic review and meta-analysis of propensity score analyses finds off-pump surgery superior to on-pump surgery in all of the assessed short-term outcomes. This advantage was statistically significant and clinically relevant for most outcomes, especially for mortality, the most valid criterion. These results agree with previous systematic reviews of randomized and nonrandomized trials. Copyright © 2010 by The American Association for Thoracic Surgery.

Meier J.J.,Ruhr University Bochum
Nature Reviews Endocrinology | Year: 2012

In healthy humans, the incretin glucagon-like peptide 1 (GLP-1) is secreted after eating and lowers glucose concentrations by augmenting insulin secretion and suppressing glucagon release. Additional effects of GLP-1 include retardation of gastric emptying, suppression of appetite and, potentially, inhibition of β-cell apoptosis. Native GLP-1 is degraded within ∼2-3 min in the circulation; various GLP-1 receptor agonists have, therefore, been developed to provide prolonged in vivo actions. These GLP-1 receptor agonists can be categorized as either short-acting compounds, which provide short-lived receptor activation (such as exenatide and lixisenatide) or as long-acting compounds (for example albiglutide, dulaglutide, exenatide long-acting release, and liraglutide), which activate the GLP-1 receptor continuously at their recommended dose. The pharmacokinetic differences between these drugs lead to important differences in their pharmacodynamic profiles. The short-acting GLP-1 receptor agonists primarily lower postprandial blood glucose levels through inhibition of gastric emptying, whereas the long-acting compounds have a stronger effect on fasting glucose levels, which is mediated predominantly through their insulinotropic and glucagonostatic actions. The adverse effect profiles of these compounds also differ. The individual properties of the various GLP-1 receptor agonists might enable incretin-based treatment of type 2 diabetes mellitus to be tailored to the needs of each patient. © 2012 Macmillan Publishers Limited. All rights reserved.

Definition of the problem "Personalised medicine" has recently gained considerable attention and has evoked a multitude of hopes in modern medicine. The identification of genetic markers enables more precise diagnoses, targeted therapy and more specific statements about the personal prognosis. Often used as a synonym for medical progress, personalised medicine promises to be more personal, better and cheaper than current medicine. Arguments (1) However, large achievements in basic genetic research do not necessarily mean better personal treatment for the majority of patients in clinical medicine. It is more likely that future clinical success in targeted therapies will be limited to subgroups of patients. In contrast, a considerable proportion of patients will have no personal benefit at all. (2) "Personalised medicine" is genetic biomarker-based targeted diagnostics and therapy. It does not focus on a more personal patient-doctor relationship, like patient-centred or person-centred medical care provides. (3) In fact so-called "personalised medicine" is a research- and economic-driven adventure governed by global stakeholders, e.g. pharmaceutical and biotechnology companies. Since economically independent and publically funded research is widely lacking, these private interest groups are setting the research agenda following their commercial interests. In this context and with the record of the current cost development of new cancer drugs in targeted therapies, there is no evidence for the promise of cost saving and of cheaper health care. (4) Furthermore "personalised medicine" is associated with ethical problems like priority setting and opportunity costs in solidarity-based public health care systems. "Personalised medicine" provides modern, highly specific and expensive diagnostics and treatments which will only serve subgroups of patients. At the same time research in other fields of clinical medicine which could serve more than some subgroups of patients, remain underfunded. A public debate on priority setting in medical research and treatment and about how societies and public health systems can influence the development of the research agenda regarding the priorities for future health care is needed. Conclusion Genetic biomarker-based "personalised medicine" does not contribute to a more personal treatment of individual patients, like in patient- or person-centred medical care. Subgroups of patients, e.g. in oncology, have medical advantages from the present progress in "personalised medicine", but not the overall majority of patients. Empirical evidence is lacking for the promise of cheaper health care through "personalised medicine"; however, based on past experience an increase of cost is more likely. © 2013 Springer-Verlag Berlin Heidelberg.

Schildmann J.,Ruhr University Bochum | Schildmann E.,Oncology and Tumour Immunology
International Journal of Clinical Practice | Year: 2013

Palliative sedation therapy (PST) has become a frequent practice in end-of-life care and advocated in the literature as a less problematic alternative to practices of physician-assisted dying, such as ending patients' lives on request or assisted suicide. However, in clinical practice, patients, healthcare professionals and other parties involved in decisions about PST are facing numerous clinical and ethical challenges. This perspective aims to analyse important challenges associated with professional decision-making about PST and to explore the recommendations of guidelines, which have been published in recent years. © 2013 John Wiley & Sons Ltd.

Prinz C.,Catholic University of Leuven | Prinz C.,Ruhr University Bochum | Voigt J.-U.,Catholic University of Leuven
Journal of the American Society of Echocardiography | Year: 2011

Background: The aim of this study was to investigate the imaging capabilities of recent hand-held ultrasound scanners. Methods: Three hundred forty-nine patients were scanned with hand-held ultrasound (HAND) and high-end echocardiography (HIGH). Segmental endocardial border delineation was scored (2 = good, 1 = poor, 0 = invisible) to describe image quality. Assessments of left ventricular (LV) dimensions, regional and global LV function, and grades of valve disease were compared. Results: The mean endocardial visibility grades were 1.6 ± 0.5 with HAND and 1.7 ± 0.4 with HIGH (P < .01). Regional wall motion was scored very similarly (κ = 0.73, P < .01). Ejection fraction assessment (bias = 1.8%, 1.96 × SD = 8.3%) and LV measurements (r = 0.99, P < .01; interventricular septum: bias = 0.91 mm, 1.96 × SD = 2.1 mm; LV end-diastolic diameter: bias = 0.5 mm, 1.96 × SD = 4.1 mm; LV posterior wall: bias = 0.61 mm, 1.96 × SD = 2.4 mm) showed negligible deviations. No pericardial effusion or valve stenosis was missed. Regurgitations missed by HAND were all graded "minimal" on HIGH. Regurgitations were mildly overestimated by HAND. Overall concordance for detection of regurgitations was very good (κ = 0.9, P < .01). Conclusions: Handheld echocardiography was feasible and missed no relevant findings. Given the future implementation of spectral Doppler capabilities, this handheld scanner can safely be used in clinical routine.© ; 2011 by the American Society of Echocardiography.

Chan A.,Ruhr University Bochum | Lo-Coco F.,University of Rome Tor Vergata
Neurology | Year: 2013

Despite the long-standing and extensive use of mitoxantrone (MTZ) for the treatment of aggressive forms of multiple sclerosis (MS), especially in Europe, its benefit-risk profile remains controversial. In particular, the risk of developing therapy-related acute leukemia (TRAL) and cardiotoxicity have led to treatment restrictions for MTZ; however, the precise risk for these severe complications is still unclear. Here we review current data on TRAL incidence, research strategies aimed at individual risk stratification, and provide recommendations for hematologic monitoring. A recent meta-analysis indicates a TRAL risk of approximately 0. 81%, more than 10-fold higher than in previously reported meta-analyses (0. 07%). There also appear to be considerable differences among countries, with recent TRAL risk estimates from Italy as high as 0. 93%, compared to the 0. 25%-0. 41% risk reported from Germany and France. Whereas methodologic differences may partly account for some of these differences, high regional variability may point to exogenous factors such as heterogeneous treatment protocols and cotreatments. In addition, genetic risk factors (MTZ metabolism, DNA repair) might contribute to the individual risk profile. The case of potentially curable MTZ-induced secondary leukemia highlights the need for close hematologic monitoring during and after therapy. Intensive collaboration between neurologists and hematologists will likely provide benefits both for research efforts aimed at unraveling TRAL pathogenesis and for clinical practice with improved identification and monitoring of patients at higher risk of MTZ-induced TRAL. This is of particular importance, since treatment alternatives, especially in secondary progressive MS, are sparse. © 2013 American Academy of Neurology.

Nauck M.A.,Diabeteszentrum Bad Lauter berg | Meier J.J.,Ruhr University Bochum
Annals of Internal Medicine | Year: 2012

Background: Recent biochemical diagnostic guidelines for insulino-mas require demonstration of hypoglycemia with inappropriately elevated (nonsuppressed) insulin, C-peptide, or proinsulin, but these criteria may overlap with those in patients without insulinomas. Use of an "amended" insulin-glucose ratio that accounts for the normal variation in insulin secretion according to prevailing glycemia may improve diagnostic accuracy. Objective: To compare the diagnostic accuracy of current diagnostic guideline criteria with the amended insulin- glucose ratio in patients with a suspected insulinoma. Design: Retrospective cohort study. Setting: 2 specialized university departments in Germany. Patients: 114 patients with suspected hypoglycemia over 10 years having diagnostic prolonged fasts. Measurements: Glucose, insulin, C-peptide, and the amended insulin-glucose ratio were measured during and at discontinuation of prolonged fasts. Results: Of 114 patients who were evaluated, 49 had surgical resection of histologically confirmed insulinomas. Insulinoma was excluded in 65 patients; follow-up for a mean of 10 years (range, 0 to 16 years) showed no progressively severe hypoglycemic events or diagnoses of insulinoma. Patients with insulinoma had lower glucose levels and higher insulin and C-peptide levels overall than did control patients at the end of prolonged fasts, but there was considerable overlap. The amended insulin- glucose ratio correctly identified 48 of 49 patients with insulinoma and excluded the diagnosis in 64 of 65 control patients, resulting in positive and negative predictive values of 0.98 (95% CI, 0.89 to 1.00) and 0.99 (CI, 0.92 to 1.00), respectively, compared with 0.75 (CI, 0.63 to 0.85) and 0.98 (CI, 0.89 to 1.00), respectively, for glucose, insulin, and C-peptide concentration criteria. Limitation: The study had a retrospective design, no proinsulin concentrations were available, and a nonspecific insulin immuno-assay (crossreactive with proinsulin) was used. Conclusion: The amended insulin- glucose ratio showed improved diagnostic accuracy over established criteria that use glucose, insulin, and C-peptide concentrations. © 2012 American College of Physicians.

Gatermann S.G.,Ruhr University Bochum
Transfusion Medicine and Hemotherapy | Year: 2011

Bacterial contaminations of blood products often originate from the flora of the donor. Normally, components of the skin flora less frequently give rise to severe or complicated infections, although their participation in such conditions has been described. In contrast, bacteria that can cause infections in immunocompetent persons may give rise to life-threatening infections when present in blood products. The latter microorganisms are wellequipped with a variety of virulence factors that contribute to their pathogenicity. © 2011 S. Karger AG, Basel.

Carroll J.B.,Western Washington University | Bates G.P.,Kings College London | Steffan J.,University of California at Irvine | Saft C.,Ruhr University Bochum | Tabrizi S.J.,University College London
The Lancet Neurology | Year: 2015

Huntington's disease is a genetic neurodegenerative disorder with symptoms that are linked to the progressive dysfunction and neuronal death in corticostriatal circuits. The causative gene (mutated HTT) is widely expressed outside the CNS and several peripheral signs of disease, including weight loss and increased proinflammatory signalling, are often seen; however, their importance in the pathophysiology of Huntington's disease is not clear. Studies in animals have shown that features of the disease involving the CNS, including synapse loss and behavioural alterations, are susceptible to modulation by treatments that target tissues and organs outside the CNS. Links between peripheral biology and neurodegeneration have also been shown in other chronic neurodegenerative diseases, suggesting that modulation of these peripheral targets can offer new approaches to therapeutic development. Treatments targeted to tissues and organs outside the CNS might therefore substantially improve the quality of life of patients with Huntington's disease, even in the absence of disease-modifying effects. © 2015 Elsevier Ltd.

Epelbaum E.,Ruhr University Bochum
Progress in Particle and Nuclear Physics | Year: 2012

In this talk some recent developments towards understanding few-nucleon and many-nucleon low-energy dynamics within chiral effective field theory are presented. © 2012 Elsevier B.V. All rights reserved.

Chaaban A.,KAUST | Sezgin A.,Ruhr University Bochum
Foundations and Trends in Communications and Information Theory | Year: 2015

Multi-way communication is a means to significantly improve the spectral efficiency of wireless networks. For instance, in a bi-directional (or two-way) communication channel, two users can simultaneously use the transmission medium to exchange information, thus achieving up to twice the rate that would be achieved had each user transmitted separately. Multi-way communications provides an overview on the developments in this research area since it has been initiated by Shannon. The basic two-way communication channel is considered first, followed by the two-way relay channel obtained by the deployment of an additional cooperative relay node to improve the overall communication performance. This basic setup is then extended to multi-user systems. For all these setups, fundamental limits on the achievable rates are reviewed, thereby making use of a linear high-SNR deterministic channel model to provide valuable insights which are helpful when discussing the coding schemes for Gaussian channel models in detail. Several tools and communication strategies are used in the process, including (but not limited to) computation, signal-space alignment, and nested-lattice codes. Finally, extensions of multi-way communication channels to multiple antenna settings are discussed. © 2015 A. Chaaban and A. Sezgin.

Houben S.,Ruhr University Bochum
IEEE Intelligent Vehicles Symposium, Proceedings | Year: 2011

Traffic sign detection and recognition is an important part of advanced driver assistance systems. Many prototype solutions for this task have been developed, and first commercial systems have just become available. Their image processing chain can be devided into three steps, preprocessing, detection, and recognition. Albeit several reliable sign recognition algorithms exist by now sign detection under real-world conditions is still unstable. Therefore, we address the first two steps of the processing chain presenting an analysis of widely used detectors, namely Hough-like methods. We evaluate several preprocessing steps and tweaks to increase their performance. Hence, the detectors are applied to a large, publicly available set of images from real-life traffic scenes. As main result we establish a new probabilistic measure for traffic sign colour detection and, based on the findings in our analysis, propose a novel Hough-like algorithm for detecting circular and triangular shapes. These improvements significantly increased detection performance in our experiments. © 2011 IEEE.

Bondarenko A.S.,Ruhr University Bochum
Analytica Chimica Acta | Year: 2012

An approach for the analysis of large experimental datasets in electrochemical impedance spectroscopy (EIS) has been developed. The approach uses the idea of successive Bayesian estimation and splits the multidimensional EIS datasets into parts with reduced dimensionality. Afterwards, estimation of the parameters of the EIS-models is performed successively, from one part to another, using complex nonlinear least squares (CNLS) method. The results obtained on the previous step are used as a priori values (in the Bayesian form) for the analysis of the next part. To provide high stability of the sequential CNLS minimisation procedure, a new hybrid algorithm has been developed. This algorithm fits the datasets of reduced dimensionality to the selected EIS models, provides high stability of the fitting and allows semi-automatic data analysis on a reasonable timescale. The hybrid algorithm consists of two stages in which different zero-order optimisation strategies are used, reducing both the computational time and the probability to overlook the global optimum. The performance of the developed approach has been evaluated using (i) simulated large EIS dataset which represents a possible output of a scanning electrochemical impedance microscopy experiments, and (ii) experimental dataset, where EIS spectra were acquired as a function of the electrode potential and time. The developed data analysis strategy showed promise and can be further extended to other electroanalytical EIS applications which require multidimensional data analysis. © 2012 Elsevier B.V.

Ciuman R.R.,Ruhr University Bochum
European Archives of Oto-Rhino-Laryngology | Year: 2012

Phytotherapeutic pharmaceuticals and herbal medicinal products with its roots in classical phytotherapeutic medicine have a well-established role in otolaryngological therapy, especially for diseases of the upper airways and acute and chronic infections. A thorough selection and application could mean huge benefit for the patient, in particular in cases with contraindications, chemo- and antibiotic resistance or patient request. Besides, it might spare other medications. Phytotherapeutic pharmaceuticals must fulfil the same criteria of quality, effectiveness and harmlessness of evidence-based medicine like chemical pharmaceuticals, although they are often prescribed due to its well established or traditional based use. This review focuses on phytotherapeutic therapies well established within the European Community for otolaryngologic disease patterns by referring to clinical studies or meta-analysis. © 2011 The Author(s).

Dietrich J.W.,Ruhr University Bochum
Medizinische Klinik - Intensivmedizin und Notfallmedizin | Year: 2012

Thyroid storm is a complicated, life-threatening form of thyrotoxicosis. The causes are multifactorial and elevated iodothyronine levels are only one of many components. Usually, the transition from thyrotoxicosis to thyroid storm is ignited by non-thyroidal triggers. This is a rare condition observed with an incidence between 0.8 and 1.4 cases per 100,000 inhabitants. Diagnosis relies primarily on clinical criteria. Multimodal therapy aims at disrupting positive feedback loops between elevated levels of free T3 or T4 and their effects on target tissues and organs. Timely diagnosis and therapy help to reduce mortality to below 35%. © 2012 Springer-Verlag.

Gurevich E.L.,Ruhr University Bochum
Applied Surface Science | Year: 2013

Here we analyze whether the laser-induced periodic surface structures (LIPSS), which appear on solid surfaces exposed to single-pulse femtosecond laser radiation, can be explained by excitation of surface plasmon-polariton waves. We demonstrate that excitation of the surface plasmons is impossible in the laser-ablation experiments, since the excitation conditions are not fulfilled. Moreover, properties and morphology of the observed periodic patterns contradict to the theory of the plasmonic nature of the LIPSS. The results are illustrated with experimental examples. © 2012 Elsevier B.V. All rights reserved.

Siegert R.,Ruhr University Bochum
Advances in Oto-Rhino-Laryngology | Year: 2010

Objectives: Due to their embryological development, auricular atresia and severe microtia are, in most cases, combined malformations. The aims of this study were firstly to develop a surgical technique for combined esthetic and functional reconstruction with a minimum of operations and secondly to evaluate its results. Study Design: Prospective clinical evaluation. Patients and Methods: Fifty-two patients with third-degree microtia and congenital aural atresia with a sound-conducting block of about 50 dB were treated. In the first operation, autogenous cartilage was harvested, and the auricular framework was fabricated and implanted. In addition, the tympanic membrane and the external ear canal were prefabricated, and stored in a subcutaneous pocket. In the second step, the elevation of the new framework was combined with the operation for atresia, utilizing the prefabricated tympanic membrane and external ear canal. In the third step, the cavum concha was deepened, and the external ear canal was opened and covered with a skin graft. Results: In total, 76% of the patients had a final conductive hearing loss of 30 dB or less. No restenosis of the new external ear canal was observed. The esthetic results of the constructed auricles are shown in this report. Conclusion: With this combination of plastic surgery for the auricle and functional surgery for the middle ear, no additional operations are necessary and the prefabrication of the external ear canal and the tympanic membrane gives stable and reliable results. This combined technique offers the best chance of optimal esthetic and functional rehabilitation for patients with these malformations. © 2010 S. Karger AG, Basel.

We used ab initio density functional theory in combination with an embedded cluster approach to calculate vibrational spectra and formation enthalpies of possible intermediates and side products (spectator species) in the synthesis of methanol out of syngas on the ZnO(0001) surface. Our investigations are based upon our previous work on possible reaction pathways and activation barriers for this reaction at oxygen vacancies on ZnO(0001). We present and discuss calculated vibrational frequencies of short-living formyl, hydroxymethylene, formaldehyde, acetale, and hydroxymethyl intermediates and compare the calculated frequencies of formate and methoxy species as well as CO and CO(2) species, at the defect free surface and at oxygen vacancies, with recent experimental findings. All investigated species show characteristic features in their spectra. Therefore, the analysis of their vibrational frequencies is a suitable mean to distinguish them and gain new insights in this reaction which is of recent experimental interest. We are able to identify the structure and characteristics of different surface species, such as monodentate and polydentate carbonate and formate species, in agreement with experimental results. © 2012 American Institute of Physics

Kochmann D.M.,California Institute of Technology | Hackl K.,Ruhr University Bochum
Continuum Mechanics and Thermodynamics | Year: 2011

The analysis and simulation of microstructures in solids has gained crucial importance, virtue of the influence of all microstructural characteristics on a material's macroscopic, mechanical behavior. In particular, the arrangement of dislocations and other lattice defects to particular structures and patterns on the microscale as well as the resultant inhomogeneous distribution of localized strain results in a highly altered stress-strain response. Energetic models predicting the mechanical properties are commonly based on thermodynamic variational principles. Modeling the material response in finite strain crystal plasticity very often results in a non-convex variational problem so that the minimizing deformation fields are no longer continuous but exhibit small-scale fluctuations related to probability distributions of deformation gradients to be calculated via energy relaxation. This results in fine structures that can be interpreted as the observed microstructures. In this paper, we first review the underlying variational principles for inelastic materials. We then propose an analytical partial relaxation of a Neo-Hookean energy formulation, based on the assumption of a first-order laminate microstructure, thus approximating the relaxed energy by an upper bound of the rank-one-convex hull. The semi-relaxed energy can be employed to investigate elasto-plastic models with a single as well as multiple active slip systems. Based on the minimization of a Lagrange functional (consisting of the sum of energy rate and dissipation potential), we outline an incremental strategy to model the time-continuous evolution of the laminate microstructure, then present a numerical scheme by means of which the microstructure development can be computed, and show numerical results for particular examples in single- and double-slip plasticity. We discuss the influence of hardening and of slip system orientations in the present model. In contrast to many approaches before, we do not minimize a condensed energy functional. Instead, we incrementally solve the evolution equations at each time step and account for the actual microstructural changes during each time step. Results indicate a reduction in energy when compared to those theories based on a condensed energy functional. © 2010 Springer-Verlag.

Fischer A.,Ruhr University Bochum | Fischer A.,Copenhagen University | Igel C.,Copenhagen University
Pattern Recognition | Year: 2014

Restricted Boltzmann machines (RBMs) are probabilistic graphical models that can be interpreted as stochastic neural networks. They have attracted much attention as building blocks for the multi-layer learning systems called deep belief networks, and variants and extensions of RBMs have found application in a wide range of pattern recognition tasks. This tutorial introduces RBMs from the viewpoint of Markov random fields, starting with the required concepts of undirected graphical models. Different learning algorithms for RBMs, including contrastive divergence learning and parallel tempering, are discussed. As sampling from RBMs, and therefore also most of their learning algorithms, are based on Markov chain Monte Carlo (MCMC) methods, an introduction to Markov chains and MCMC techniques is provided. Experiments demonstrate relevant aspects of RBM training. © 2013 Elsevier Ltd. All rights reserved.

Witala H.,Jagiellonian University | Glockle W.,Ruhr University Bochum
Physical Review C - Nuclear Physics | Year: 2011

Large discrepancies between quasifree neutron-neutron (nn) cross section data from neutron-deuteron (nd) breakup and theoretical predictions based on standard nucleon-nucleon (NN) and three-nucleon (3N) forces are pointed out. The nn 1S0 interaction is shown to be dominant in that configuration and has to be increased to bring theory and data into agreement. Using the next-to-leading order 1S0 interaction of chiral perturbation theory, we demonstrate that the nn quasifree scattering cross section depends only slightly on changes of the nn scattering length but is very sensitive to variations of the effective range parameter. In order to account for the reported discrepancies one must decrease the nn effective range parameter by ≈12% from its value implied by charge symmetry and charge independence of nuclear forces. © 2011 American Physical Society.

We aimed to identify predictors of anamnestic hypoglycaemia in type-2 diabetic patients on oral mono- or dual oral combination antidiabetic pharmacotherapy. DiaRegis is a prospective registry in type-2 diabetic patients in primary care. Odds ratios (OR) with 95% confidence intervals were determined from univariate logistic regression. Using multivariate logistic regression analysis with stepwise backward selection at an alpha of 0.05 independent predictors of hypoglycaemia were determined. 3,808 patients had data on hypoglycaemia available (median age 65.9 years, 46.6% female). 10.8% had at least one anamnestic hypoglycaemic episode within the previous 12 months. Patients with hypoglycaemia received more sulfonylureas (OR 2.16; 95%CI 1.75-2.67) and less metformin (OR 0.64; 95%CI 0.50-0.82). On top of metformin, patients with thiazolidine (OR 0.50; 95%CI 0.28-0.89) and DPP-4 inhibitor use (OR 0.34; 95%CI 0.16-0.70) had a decreased risk for hypoglycaemia while it was again increased with sulfonylureas (OR 2.08; 95%CI 1.44-2.99). Age < 65 years was an independent predictor of a reduced hypoglycaemia incidence (OR 0.76; 95%CI 0.59-0.96), low HbA1c (OR 1.68; 95%CI 1.31-2.14), stroke/TIA (OR 1.72; 95%CI 1.08-2.72), heart failure (OR 1.77; 95%CI 1.28-2.45), and the use of sulfonylureas (OR 2.58; 95%CI 2.03-3.29) were independent predictors of increased risk. The results indicate that the risk of hypoglycaemia might be substantially reduced by carefully selecting antidiabetic pharmacotherapy in patients with type-2 diabets in primary care.

Eyding J.,Ruhr University Bochum
Ultraschall in der Medizin (Stuttgart, Germany : 1980) | Year: 2011

Atherosclerotic alterations of the internal carotid artery frequently result in ischemic stroke. However, it remains unclear which specific factor mainly causes an increased risk of stroke. Constant improvements of the diagnostic possibilities of ultrasonic examinations provide increasingly profound insight into plaque alterations. If "risk plaque" could be reliably identified, the therapeutic decision for either medical or surgical treatment could be made more rationally. In this review, we summarize current developments in the ultrasound imaging of atherosclerotic changes in carotid artery disease with special emphasis on technical aspects and the rationale of contrast imaging of plaque vascularization. Methodological limitations and possible future applications are discussed. © Georg Thieme Verlag KG Stuttgart · New York.

Chubukov A.V.,University of Wisconsin - Madison | Eremin I.,Ruhr University Bochum | Eremin I.,Kazan Federal University
Physical Review B - Condensed Matter and Materials Physics | Year: 2010

We consider the variation in the field-induced component of the specific heat C (H) with the direction of the applied field in Fe pnictides within quasiclassical Doppler-shift approximation with special emphasis to recent experiments on FeSe0.4 Te0.6. We show that for extended s -wave gap with no nodes, C (H) has cos4 component, where is the angle between H and the direction between hole and electron Fermi surfaces. The maxima of C (H) are at π/4, 3π/4, etc., if the applied field is smaller than H0 ≤1T, and at =0, π/2, etc., if the applied field is larger than H0. The angle dependence of C (H), the positions of the maxima, and the relative magnitude of the oscillating component are consistent with the experiments performed in the field of 9TH0. We show that the observed cos4 variation does not hold if the s -wave gap has accidental nodes along the two electron Fermi surfaces. © 2010 The American Physical Society.

Du Y.A.,Wake forest University | Du Y.A.,Ruhr University Bochum | Holzwarth N.A.W.,Wake forest University
Physical Review B - Condensed Matter and Materials Physics | Year: 2010

Lithium phosphorus oxynitride materials have been investigated for many years, especially in relation to the thin-film electrolyte LiPON, developed at Oak Ridge National Laboratory. We have carried out first-principles simulations of related crystalline materials as a first step toward understanding the sources of stability and mechanisms of Li-ion conductivity in these materials. In addition to a comprehensive survey of known crystalline materials related to LiPON, we have also predicted some materials. For example, starting with crystalline LiPO3 which has twisted phosphate chains, we considered the possibility of modifying the structure by substituting N and Li for O. The optimized structures were computed to have regularized phosphate chains which form planar -P-N-P-N- backbones. To the best of our knowledge, the predicted crystals, which we call s1 -Li2 PO2 N with a 24-atom unit cell and s2 -Li2 PO2 N with a 12-atom unit cell, have not yet been observed experimentally. We suggest several possible exothermic reaction pathways to synthesize these crystals. © 2010 The American Physical Society.

May C.,Ruhr University Bochum
Methods in molecular biology (Clifton, N.J.) | Year: 2011

In the past decade, major developments in instrumentation and methodology have been achieved in proteomics. For proteome investigations of complex biological samples derived from cell cultures, tissues, or whole organisms, several techniques are state of the art. Especially, many improvements have been undertaken to quantify differences in protein expression between samples from, e.g., treated vs. untreated cells and healthy vs. control patients. In this review, we give a brief insight into the main techniques, including gel-based protein separation techniques, and the growing field of mass spectrometry.

Al-Benna S.,Ruhr University Bochum
Ostomy Wound Management | Year: 2012

Patients should receive care based on the best available scientific knowledge. Clinical wound care guidelines have been created using many methodologies' but many remain consensus-based. A consensus-based approach is no longer considered adequate or appropriate. The best guidelines are developed from a systematic examination and appraisal of good evidence from well-conducted trials. The development process must be transparent' utilize an accepted evidence rating system' be supported by appropriate clinical expertise' and lead to unambiguous recommendations. Prospective validation studies are important as part of the development process' especially for areas of care with limited literature-based evidence. Wound care will become a process of applying the best data available to the clinical situation. The ultimate use of guidelines will be the development of evidence-based' validated clinical tools that can be integrated with existing patient data and available to the wound care professional at the consultation.

Background: 5% to 8% of 70-year-olds and some 10% of persons over age 80 have atrial fibrillation (AF). Methods: Selective literature review. Results: New scoring schemes (CHA2DS2-VASc score, HASBLED score) have been introduced to enable more accurate estimation of the risk of stroke and hemorrhage in patients with AF. These scores are calculated on the basis of clinical data (left ventricular dysfunction, hypertension, age, diabetes, prior stroke, vascular diseases, sex, renal or hepatic dysfunction, bleeding, labile INR values, consumption of medications and alcohol) and are used to determine the potential indication for, and appropriate type of, anticoagulation in the individual AF patient. Hemodynamically unstable patients with rapid AF should undergo DC cardioversion at once. Patients with permanent AF should be given beta-blockers, calcium antagonists, or digitalis for rate control, with a target rate below 110/minute. A recently introduced drug, dronedarone, is used for rhythm control and has relatively few side effects. Patients with AF and impaired left ventricular function should be given amiodarone. Rhythm control has not been found to prolong life any more than rate control. Patients with a CHA2DS2-VASc score of 2 or above should be orally anticoagulated. Those with a score of 1 can be treated with aspirin (75 to 325 mg daily); those with a score of 0 do not need antithrombotic treatment. A HAS-BLED score of 3 or above is associated with a high risk of bleeding. Pulmonary vein isolation is an established method of treating symptomatic AF, with a success rate of 60% to 80%. Surgical procedures are pos - sible in AF patients who need additional cardiac surgery. Conclusion: The treatment strategy for AF must be individual - ized on the basis of the patient's clinical manifestations. The mainstay of treatment is anticoagulation; the indication for anticoagulation depends on the patient's age, underlying disease, and left ventricular function.

Gabl S.,University of Vienna | Steinhauser O.,University of Vienna | Weingartner H.,Ruhr University Bochum
Angewandte Chemie - International Edition | Year: 2013

Frequency-dependent NOE: A new model theory was used to analyze the spatial range of the intermolecular nuclear Overhauser effect in ionic liquids. The spatial range undergoes a transition from long-range nature at low frequency to a short-range character at high frequencies. The experimentally accessible cross-relaxation rate involves contributions from both regimes, but the long-range component dominates. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Bialonski S.,University of Bonn | Wendler M.,Ruhr University Bochum | Lehnertz K.,University of Bonn
PLoS ONE | Year: 2011

We investigate interaction networks that we derive from multivariate time series with methods frequently employed in diverse scientific fields such as biology, quantitative finance, physics, earth and climate sciences, and the neurosciences. Mimicking experimental situations, we generate time series with finite length and varying frequency content but from independent stochastic processes. Using the correlation coefficient and the maximum cross-correlation, we estimate interdependencies between these time series. With clustering coefficient and average shortest path length, we observe unweighted interaction networks, derived via thresholding the values of interdependence, to possess non-trivial topologies as compared to Erdös-Rényi networks, which would indicate small-world characteristics. These topologies reflect the mostly unavoidable finiteness of the data, which limits the reliability of typically used estimators of signal interdependence. We propose random networks that are tailored to the way interaction networks are derived from empirical data. Through an exemplary investigation of multichannel electroencephalographic recordings of epileptic seizures - known for their complex spatial and temporal dynamics - we show that such random networks help to distinguish network properties of interdependence structures related to seizure dynamics from those spuriously induced by the applied methods of analysis. © 2011 Bialonski et al.

Oldenburg O.,Ruhr University Bochum
Circulation Journal | Year: 2012

Sleep-disordered breathing (SDB) with predominant obstructive or central sleep apnea (OSA/CSA) with Cheyne-Stokes respiration (CSR) is a common, but underestimated and underappreciated, comorbidity in patients with heart failure (HF). Regardless of the type of HF (systolic or diastolic) or its etiology (ischemic, non-ischemic, valvular etc), the prevalence of SDB is remarkably high in this patient group, at 70-76%. Even more so in HF than in the general population, OSA and CSA in particular are independently associated with an impaired prognosis. This review details the pathophysiology of CSA-CSR in HF, highlights the challenges and tools available for diagnosis, explains the concept of adaptive servoventilation (ASV) therapy, and summarizes the existing literature on the use of ASV therapy in HF patients in general and HF with reduced ejection fraction in particular.

Braun J.,Ruhr University Bochum | Kudrin A.,Celltrion Inc.
Immunotherapy | Year: 2015

Biosimilars are biologic medical products whose active drug substance is made by a living organism or derived from it. The term is used to describe a subsequent version of an innovator biopharmaceutical product aiming at approval following patent expiry on the reference product. Biosimilars of monoclonal need to demonstrate similar but not identical quality of nonclinical and clinical attributes. Not all data of the originator product need to be recapitulated, as large numbers of patient-years of exposure data are already available. Thus, biosimilar development is largely based on the safety profiles of the originator product. The evaluation of biosimilarity includes immunogenicity attributed risks. CT-P13 (Remsima™/Inflectra™, Celltrion/Hospira), a biosimilar of the innovator drug infliximab (INF), was the first approved complex biosimilar monoclonal antibody in the EU, within the framework of WHO, EMA and US FDA biosimilar guidelines. CT-P13 has shown analytical and nonclinical features highly similar to INF including pharmacokinetics, efficacy, safety and immunogenicity profiles in ankylosing spondylitis and rheumatoid arthritis. The objective of this article is to highlight the recent biosimilar development and to review the results from the studies PLANETRA and PLANETAS, which have supported the approval of CT-P13 for several indications. © 2015 Future Medicine Ltd.

Jacob A. Belzen's Towards cultural psychology of religion: principles, approaches and applications is the most important book on the topic to date and offers an excellent overview of theoretical, methodological, and historical aspects of the psychology of religion and cultural psychology. In this commentary, I concur with Belzen's main arguments and offer additional support for them by presenting a historical perspective that allows us to see his suggestions as the latest and most refined approach within a meritorious tradition of social scientific thinking. My critical comments pertain to the inadequate integration of concerns stated by indigenous psychology. © 2010 Taylor & Francis.

Zhang M.,Florida Institute of Technology | Schlickeiser R.,Ruhr University Bochum
Astrophysical Journal | Year: 2012

Recently, it was demonstrated that stochastic acceleration of particles going through a series of compressive plasma waves can be efficient and fast. It could be too fast so that the pressure built up by the accelerated particles may in turn modify the amplitude of waves to prevent the particles from having an exploding pressure. We call this condition pressure balance. In this paper, we take into account the fact that active acceleration of particles only occupies a limited volume of space due to a possible intermittent nature of plasma waves or turbulence. We develop a bimodal acceleration theory that treats the populations of particles in the active and inactive acceleration regions separately and allows the two populations to exchange particles efficiently. Under the requirement of the pressure balance condition, we show that the system automatically produces a solution of v -5 steady state distribution for the accelerated particles. It is found that the v -5 distribution is more robust and easier to achieve with a small volume of intense particle acceleration. These properties explain why the v -5 distribution is commonly observed in space. We apply our model to pickup ion propagation and acceleration throughout the entire heliosphere. Our results can reproduce various observations in some great detail. We also found that this mechanism could be responsible for producing anomalous cosmic rays deep in the heliosheath. © 2012. The American Astronomical Society. All rights reserved.

Meilikhov M.,Kyoto University | Furukawa S.,Kyoto University | Furukawa S.,Japan Science and Technology Agency | Hirai K.,Kyoto University | And 3 more authors.
Angewandte Chemie - International Edition | Year: 2013

Janus MOF: Thin films consisting of noncentrosymmetric heterostructured metal-organic frameworks (MOFs) were fabricated directly on quartz-crystal microbalance (QCM) sensor devices. Depending on the spatial configuration of two frameworks, the thin MOF films could tune the affinity for analytes, thus giving high selectivity to the QCM sensors. © 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

BACKGROUND: Atopic dermatitis (AD) is a chronic inflammatory skin disorder caused by complex interaction of genetic and environmental factors. Besides mutations in the filaggrin gene, leading to impaired skin barrier function, variation in genes encoding additional skin proteins has been suggested to contribute to disease risk. Laminin 5, playing an important role in skin integrity, is composed of three subunits encoded by the LAMA3, LAMB3 and LAMC2 genes in which biallelic mutations cause epidermolysis bullosa junctionalis. We aimed at evaluating the role of variation in the LAMA3, LAMB3 and LAMC2 genes for AD pathogenesis.METHODS: 29 single nucleotide polymorphisms (SNPs) were genotyped in the three genes in a German AD case-control cohort comprising 470 unrelated AD patients and 320 non-atopic controls by means of restriction enzyme digestion. Allele, genotype and haplotype frequencies were compared between cases and controls using chi-square testing and the Haploview software.RESULTS: Several SNPs in the LAMA3 gene showed significant association with AD in our cohort (p <0.01), while we did not detect association with variations in the LAMB3 and LAMC2 genes. Haplotype analysis additionally revealed several significantly associated haplotypes in the LAMA3 gene. Due to extensive linkage disequilibrium, though, we were not able to further differentiate the specific disease causing variation(s) in this region.CONCLUSIONS: We established the LAMA3 gene as novel potential susceptibility gene for AD. Additional studies in independent cohorts are needed to replicate these results.

Persoh D.,Ruhr University Bochum
Fungal Diversity | Year: 2015

Approaches for the cultivation-independent analysis of microbial communities are summarized as meta’omics, which predominantly includes metagenomic, -transcriptomic, -proteomic and -metabolomic studies. These have shown that endophytic, root-associated and soil fungal communities are strongly shaped by associated plant species. The impact of plant identity on the composition of its litter-associated fungal community remains to be disentangled from the impact of litter chemistry. The composition of the plant community also shapes the fungal community. Most strikingly, adjacent plant species may share mycorrhizal symbionts even if the plants usually have different types of mycorrhizal fungi associated with them (ectomycorrhizal, ericoid and arbuscular mycorrhizal fungi). Environmental parameters weakly explain fungal community composition globally, and their effect is inconsistent at local and regional scales. Decrease in similarity among communities with increasing distance (i.e. distance decay) has been reported from local to global scales. This pattern is only exceptionally caused by spatial dispersal limitation of fungal propagules, but mostly due to the inability of the fungi to establish at the particular locality (i.e. environmental filtering or competitive exclusion). Fungal communities usually undergo pronounced seasonal changes and also differ between consecutive years. This indicates that development of the communities is usually not solely cyclic. Meta’omic studies challenge the classical view of plant litter decomposition. They show that mycorrhizal and (previously) endophytic fungi may be involved in plant litter decomposition and only partly support the idea of a succession from an Ascomycota to a Basidiomycota-dominated community. Furthermore, vertical separation of saprotrophic and mycorrhizal species in soil and sequential degradation from easily accessible to ‘recalcitrant’ plant compounds, such as lignin, can probably not be generalized. The current models of litter decomposition may therefore have to be eventually refined for certain ecosystems and environmental conditions. To gain deeper insights into fungal ecology, a meta’omic study design is outlined which focuses on environmental processes, because fungal communities are usually taxonomically diverse, but functionally redundant. This approach would initially identify dynamics of chemical shifts in the host and/or substrate by metametabolomics. Detected shifts would be subsequently linked to microbial activity by correlation with metatranscriptomic and/or metaproteomic data. A holistic trait-based approach might finally identify factors shaping taxonomic composition in communities against the dynamics of the environmental process(es) they are involved in. © 2015, School of Science.

Barthel P.,University of Groningen | Haas M.,Ruhr University Bochum | Leipski C.,Max Planck Institute for Astronomy | Wilkes B.,Harvard - Smithsonian Center for Astrophysics
Astrophysical Journal Letters | Year: 2012

During the first half of the universe's life, a heyday of star formation must have occurred because many massive galaxies are in place after that epoch in cosmic history. Our observations with the revolutionary Herschel Space Observatory reveal vigorous optically obscured star formation in the ultra-massive hosts of many powerful high-redshift 3C quasars and radio galaxies. This symbiotic occurrence of star formation and black hole driven activity is in marked contrast to recent results dealing with Herschel observations of X-ray-selected active galaxies. Three archetypal radio galaxies at redshifts 1.132, 1.575, and 2.474 are presented here, with inferred star formation rates of hundreds of solar masses per year. A series of spectacular coeval active galactic nucleus/starburst events may have formed these ultra-massive galaxies and their massive central black holes during their relatively short lifetimes. © © 2012. The American Astronomical Society. All rights reserved..

Adolph D.,Ruhr University Bochum | Meister L.,Heinrich Heine University Dusseldorf | Pause B.M.,Heinrich Heine University Dusseldorf
Frontiers in Human Neuroscience | Year: 2013

During emotion perception, context is an important source of information. Whether contextual cues from modalities other than vision or audition influence the perception of social emotional information has not been investigated.Thus, the present study aimed at testing emotion perception and regulation in response to fearful facial expressions presented in the context of chemosensory stimuli derived from sweat of anxious individuals. In groups of high (HSA) and low socially anxious (LSA) participants we recorded the startle reflex (Experiment I), and analysed event-related potentials (ERPs; Experiment II) while they viewed anxious facial expressions in the context of chemosensory anxiety signals and chemosensory control stimuli. Results revealed that N1/P1 and N170 amplitudes were larger while Late Positive Potential (LPP) activity was smaller for facial expressions presented in the context of the anxiety and the chemosensory control stimulus as compared to facial expressions without a chemosensory context. Furthermore, HSA participants were highly sensitive to the contextual anxiety signals. They showed enhanced motivated attention allocation (LPP, Study II), as well aslarger startle responses towards faces in the context of chemosensory anxiety signals than did LSA participants (Study I). Chemosensory context had no effect on emotion regulation, and both LSA and HSA participants showed effective emotion regulation (Study I and II). In conclusion, both anxiety and chemosensory sport context stimuli enhanced early attention allocation and structural encoding, but diminished motivated attention allocation to the facial expressions. The current results show that visual and chemosensory information is integrated on virtually all levels of stimulus processing and that socially anxious individuals might be especially sensitive to chemosensory contextual social information.

Schlickeiser R.,Ruhr University Bochum
Astrophysical Journal | Year: 2015

The analytical theory of diffusive cosmic-ray acceleration at parallel stationary shock waves with magnetostatic turbulence is generalized to arbitrary shock speeds Vs = β1c, including, in particular, relativistic speeds. This is chieved by applying the diffusion approximation to the relevant FokkerPlanck particle transport equation formulated in the mixed comoving coordinate system. In this coordinate system, the particle?s momentum coordinates p and μ = p∥/ p are taken in the rest frame of the streaming plasma, whereas the time and space coordinates are taken in the observer?s system. For magnetostatic slab turbulence, the diffusionconvection transport equation for the isotropic (in the rest frame of the streaming plasma) part of the particle?s phase space density is derived. For a step-wise shock velocity profile, the steady-state diffusionconvection transport equation is solved. For a symmetric pitch-angle scattering FokkerPlanck coefficient, Dμμ (-μ) = Dμ μ (μ), the steady-state solution is independent of the microphysical scattering details. For nonrelativistic mono-momentum particle injection at the shock, the differential number density of accelerated particles is a Lorentzian-type distribution function, which at large momenta approaches a power-law distribution function N (p ≥ pc ) ∝ p- with the spectral index (1β)=1 [3/(⌈ 1 √r 2 - β12 - 1) 1 + 3β21]. For nonrelativistic (β1 蠐 1) shock speeds, this spectral index agrees with the known result (β1 蠐 1) ≃ (r + 2) (r - 1), whereas for ultrarelativistic (Γ1 蠑 1) shock speeds the spectral index value is close to unity. © 2015. The American Astronomical Society. All rights reserved.

Steimel A.,Ruhr University Bochum
Advances in Electrical and Computer Engineering | Year: 2010

After de-regulation of the former state-owned railways and severe restructuring of the railway industry in the last 15 years, more innovative vehicle concepts saw the light of the day. Power electronics, already formerly being a pacemaker for progress of traction vehicles, brought forth an utmost standardization of the main drive by means of the IGBT-converter-fed induction motor drive. This is independent of the railway supply voltage system or of a diesel prime mover, for locomotives, high-speed and mass-transit trains as well as for tramways. Vehicles able to operate on all four European railway voltage systems have become feasible and are used now widely. New trends as Permanent-Magnet Synchronous Motors or Medium-Frequency Transformers are discussed, and a short overlook over actual field-oriented highperformance motor control systems - including a speedsensorless variant - is given. Power electronics dominates the field of conversion of the 16.7-Hz railway supply power, typical for Central Europe, from the 50-Hz three-phase utility grid. © 2010 AECE.

Kerasnoudis A.,Ruhr University Bochum
Journal of Neuroimaging | Year: 2014

BACKGROUND AND PURPOSE: Multifocal motor neuropathy (MMN) is an acquired, immune mediated, and commonly associated with antiganglioside antibodies against GM1 lower motor neuropathy, with an incidence of 1 per 100,000. The usual age of onset is between 20 and 50 years and men appear to be more often affected than women. Patients usually present with multifocal weakness that can be localized to named nerve distributions. METHODS: The gold standard for the diagnosis is the electrophysiological detection of focal, partial conduction block of motor fibers without involvement of sensory fibers, at sites that are uncommon areas of compression. The diagnostic sonography of the peripheral nervous system is a rapidly evolving and constantly expanding imaging field in the last years, especially in patients presenting with signs of polyneuropathy. RESULTS: We report for the first time a correlation of the sonographic and electrophysiological findings in a patient with MMN. CONCLUSION: We draw the attention on the usefulness of ultrasonography for detecting and diagnosing segmental lesions of the peripheral nerves in MMN and other immune mediated neuropathies, especially in cases where a nervous segment cannot be easily explored in terms of inching technique. © 2012 by the American Society of Neuroimaging.

Guneysu T.,Ruhr University Bochum
Journal of Cryptographic Engineering | Year: 2011

This article presents a unique design approach for the implementation of standardized symmetric and asymmetric cryptosystems on modern FPGA devices. In contrast to many other FPGA implementations that algorithmically optimize the cryptosystems for being optimally placed in the generic array logic, our primary implementation goal is to shift as many cryptographic operations as possible into specific hard cores that have become available on many reconfigurable devices. For example, some of these dedicated functions are designed to provide large blocks of memory or fast arithmetic functions for Digital Signal Processing applications that can also be adopted for efficient cryptographic implementations. Based on these dedicated functions, we present specific design approaches that enable a performance for the symmetric AES block cipher (FIPS 197) of up to 55 GBit/s and a throughput of more than 30. 000 scalar multiplications per second for asymmetric Elliptic Curve Cryptography over NIST's P-224 prime (FIPS 186-3). © 2011 Springer-Verlag.

Nagel F.,Zern a Ingenieure Gmbh | Meschke G.,Ruhr University Bochum
Tunnelling and Underground Space Technology | Year: 2011

Adequate consideration of the various interactions between the Tunnel Boring Machine (TBM) and the surrounding underground is a pre-requisite for reliable prognoses in shield supported tunneling based upon numerical analysis. In addition to face support and the grouting of the annular gap the contact conditions along the shield skin between the moving TBM and the surrounding, deforming soil constitute the most relevant component of TBM-soil interactions in mechanized tunneling. This paper is concerned with the analysis of the interface conditions between the shield skin and the soil and its adequate numerical representation in the context of a process-oriented numerical simulation model for mechanized tunneling. The situation around the shield skin is influenced by the design of the Tunnel Boring Machine, the deformational behavior of the surrounding underground and by a possible inflow of process liquids into the steering gap. A novel simulation method is proposed which allows to model the viscous flow of the process liquids into the steering gap and its interactions with the face support, the tail void grouting, the deforming soil and the moving TBM. The proposed numerical model for the TBM-soil interaction is part of a recently developed three-dimensional, process-oriented finite element model for shield tunneling (Nagel et al., 2010). It allows to investigate the effects of the inflow of process liquids into the steering gap during TBM advance considering realistic machine-related and geological conditions. It is, in particular, capable to compute the pressure distribution within the developing liquid film in association with the face support and grouting conditions and to predict its influence on the surface settlements and the overall TBM-soil interaction affecting, e.g. the hydraulic jack forces or shield deformations. © 2010 Elsevier Ltd.

Timmann D.,University of Duisburg - Essen | Daum I.,Ruhr University Bochum
Behavioural Neurology | Year: 2010

Many human lesion und functional brain imaging studies suggest involvement of the cerebellum in cognitive functions. However, negative and inconsistent findings are rarely discussed. It is still an open question as to which areas of cognition the cerebellum contributes, as well as how, and to what extent. Frequently cited earlier findings in one area of cognition have been challenged in more recent studies, that is the cerebellum may not be directly involved in attention. Furthermore, disorders in patients with acquired cerebellar disease are frequently mild and less severe compared to lesions of the corresponding areas of the cerebral cortex. Patients with cerebellar disease often perform within the normal range of neuropsychological test norms. This pattern is illustrated based on general intelligence and verbal working memory, which have been assessed by a large number of authors using comparable tests. Findings, however, appear to be more pronounced in individual cases with acute onset cerebellar disorders and in children, in particular with congenital disease. The review suggests that the inconsistencies in cognitive impairments may offer clues as to the nature of cerebellar cognitive involvement. © 2010 - IOS Press and the authors. All rights reserved.

Stefanis N.G.,Ruhr University Bochum
Acta Physica Polonica B, Proceedings Supplement | Year: 2013

This report attempts to capture the essential workings of gauge links (Wilson lines) inside gauge-invariant formulations of parton distribution functions in QCD and gain some deeper insight into their key (renormalization) properties. We show, in particular, that the one-loop anomalous dimension of the Cherednikov-Stefanis quark TMD PDF is in the lightcone gauge A+ = 0, combined with the Mandelstam-Leibbrandt pole prescription, the same as that obtained in the special covariant gauge a = -3, leaving no uncancelled rapidity singularities.

Schwabe L.,Ruhr University Bochum | Pruessner J.C.,McGill University
Biological Psychiatry | Year: 2014

The processes of memory formation and storage are complex and highly dynamic. Once memories are consolidated, they are not necessarily fixed but can be changed long after storage. In particular, seemingly stable memories may re-enter an unstable state when they are retrieved, from which they must be re-stabilized during a process known as reconsolidation. During reconsolidation, memories are susceptible to modifications again, thus providing an opportunity to update seemingly stable memories. While initial demonstrations of memory reconsolidation came mainly from animal studies, evidence for reconsolidation in humans is now accumulating as well. Here, we review recent advances in our understanding of human memory reconsolidation. After a summary of findings on the reconsolidation of human fear and episodic memory, we focus particularly on recent neuroimaging data that provide first insights into how reconsolidation processes are implemented in the human brain. Finally, we discuss the implications of memory modifications during reconsolidation for the treatment of mental disorders such as posttraumatic stress disorder and drug addiction. © 2014 Society of Biological Psychiatry.

Pox C.P.,Ruhr University Bochum
Digestion | Year: 2014

Background: Colorectal cancer (CRC) is one of the most common cancers worldwide and a good candidate for screening programmes. However, there is controversy concerning which of the available screening tests should be used. Summary: There is general agreement that screening for CRC in the asymptomatic population should begin at the age of 50. Several different screening methods are available which can be separated into those that mainly detect cancers: faecal occult blood tests [guaiac (FOBT) and immunochemical (FIT)], genetic stool tests, blood tests and the M2-pyruvate kinase (M2-PK) test. Methods that detect cancers and polyps are colonoscopy, sigmoidoscopy, CT-colonography (CT-C) and colon capsule endoscopy. The only tests for which a reduction in CRC mortality compared to no screening have been proven in randomized trials are FOBT and sigmoidoscopy. Several trials suggest that FIT are superior to FOBT in terms of detection rates of cancers and advanced adenomas and possibly compliance. There is indirect evidence suggesting efficacy of colonoscopy as a screening test. The role of CT-C is controversial. There is data suggesting a good sensitivity for neoplasia >9 mm with a lower sensitivity for smaller neoplasia. However, radiation exposure is considered a major limitation in some countries. Unresolved questions include the lesion cut-off for referral to colonoscopy and work-up of extracolonic findings. For other methods, like genetic stool testing using newer markers, blood tests, capsule endoscopy and M2-PK, there is currently insufficient data on screening of the asymptomatic population. Key Messages: Colorectal screening is recommended and should be performed in the form of an organized programme. If detection of early-stage cancers is the aim of a screening programme, FIT seem to be superior to FOBT. If detection and removal of adenomas is the aim of a screening programme, endoscopic methods seem to be good alternatives. Sigmoidoscopy is easier to perform but will likely only have an effect on distal cancers. Colonoscopy is more invasive but enables inspection of the whole colon. The role of CT-C, capsule endoscopy, genetic stool tests, blood tests and M2-PK is currently unknown. © 2014 S. Karger AG, Basel.

Background: Endovenous treatments are presented by the sector (and to some extent by medical practitioners) as a minimally invasive alternative to vein stripping surgery. In the era of evidence-based medicine, such claims need to be confirmed by means of randomised controlled trials (RCTs). The aim of our study was to review the available data to determine whether stripping surgery is actually inferior in valid comparative trials. Methods: RCTs identified in a database search as comparing stripping surgery with laser or radiofrequency treatment were assessed with regard to their quality. Parameters of painfulness and duration of recovery were also compared. Results: The quality of RCTs dealing with endovenous treatment is poor. Lack of multicentricity (83%), insufficient number of cases (83%) and lack of independence (33%) were the most common quality defects. Laser therapy was not shown to have any clear advantage over stripping surgery with respect to parameters of pain or convalescence. However, these parameters were significantly better with radio-frequency therapy than with surgery. Conclusions: A valid comparison of techniques shows that the data available at present are mostly poor and unreliable. There are still not enough independent trials with sufficient case numbers and multicentre data collection to demonstrate that endovenous treatments have a significant advantage over stripping surgery. © Schattauer 2012.

Adamietz I.A.,Ruhr University Bochum
Frontiers of Radiation Therapy and Oncology | Year: 2010

The intrathoracic growth of the tumor causes several severe symptoms as cough, dyspnea, chest pain, hemoptysis, hoarseness, anorexia/nausea, and dysphagia. In patients with manifest or threatening symptoms radiotherapy (RT) as an effective measure should be implemented into the management concept. Palliative RT radiotherapy prefers short hypofractionated schemas (e.g. 10 × 3 Gy, 4 × 5 Gy, 2 × 8 Gy, 1 × 10 Gy). Careful radiation planning supports the precision of palliative RT and reduces significantly the complication rate. A good response and prolonged palliation effects (6-12 months) can be achieved in many cases. However, the minimum biologically equivalent dose should not be less than 35 Gy. RT produces a good outcome in all types of metastases of lung carcinoma. In emergencies like VCSS or spinal cord compression RT should be initiated immediately. The selection of the optimal therapy for locally advanced lung carcinoma with malignant airway obstruction is difficult. Both brachytherapy and percutaneous irradiation are effective, however published results including local a sum of response, functionality and life quality demonstrates more benefit by percutaneous RT. Due to different physical properties of these two methods the combination of brachytherapy and external beam irradiation may be advantageous. © 2010 S. Karger AG.

Behler J.,Ruhr University Bochum
Journal of Physics Condensed Matter | Year: 2014

The development of interatomic potentials employing artificial neural networks has seen tremendous progress in recent years. While until recently the applicability of neural network potentials (NNPs) has been restricted to low-dimensional systems, this limitation has now been overcome and high-dimensional NNPs can be used in large-scale molecular dynamics simulations of thousands of atoms. NNPs are constructed by adjusting a set of parameters using data from electronic structure calculations, and in many cases energies and forces can be obtained with very high accuracy. Therefore, NNP-based simulation results are often very close to those gained by a direct application of first-principles methods. In this review, the basic methodology of high-dimensional NNPs will be presented with a special focus on the scope and the remaining limitations of this approach. The development of NNPs requires substantial computational effort as typically thousands of reference calculations are required. Still, if the problem to be studied involves very large systems or long simulation times this overhead is regained quickly. Further, the method is still limited to systems containing about three or four chemical elements due to the rapidly increasing complexity of the configuration space, although many atoms of each species can be present. Due to the ability of NNPs to describe even extremely complex atomic configurations with excellent accuracy irrespective of the nature of the atomic interactions, they represent a general and therefore widely applicable technique, e.g. for addressing problems in materials science, for investigating properties of interfaces, and for studying solvation processes. © 2014 IOP Publishing Ltd.

Coimbra R.,University of Granada | Immenhauser A.,Ruhr University Bochum | Oloriz F.,University of Granada
Earth-Science Reviews | Year: 2014

Chemostratigraphy applied to ancient marine carbonates is commonly based on one-dimensional (stratigraphic) sections or core data. As demonstrated from modern oceans, this approach underestimates the spatial complexity of physico-chemical seawater properties. Here, a several-hundred-kilometer long transect consisting of seven Upper Jurassic sections from settings ranging from (proximal) neritic middle shelf to the epioceanic (distal) fringe across the southern and eastern palaeomargins of the Iberian sub-plate reveals variability in sedimentologic, stratigraphic, and geochemical records. The comparison of isotopic and elemental data from different carbonate materials (matrix micrite, carbonate cements in veinlets, belemnite rostra, and ammonite shells) reveals differential diagenetic pathways. Microfacies, cathodoluminescence and geochemical data retrieved from biostratigraphically well constrained sections reveal that epioceanic matrix micrite geochemical data provide valuable proxies for palaeo-seawater properties. Our data are reviewed in the context of published Late Jurassic records. The outcome shows a higher level of complexity including the potential admixture of marine, continental, and diagenetic geochemical signals in the epicontinental record. The stratigraphic trend in carbon isotopes of epioceanic sections agrees upon that of Upper Jurassic reference sections from the northern Tethyan margins, while oxygen isotope ratios are relatively 18O-enriched. Palaeo-seawater temperatures across the transect investigated were estimated using δ18O as tentative proxy for interpreting distance from shore, differences in water masses, relative depth variations, and potential local forcing factors. Palaeoenvironmental conditions evaluated through the combined record of isotope (δ18O), elemental (Mn), and skeletal content contrast with relative fluctuations in sea level. Site-specific changes in palaeoceanographic parameters such as water depth, seawater temperature, salinity and upwelling are considered in comparison to examples from ancient and modern oceans. © 2014 Elsevier B.V.

Behler J.,Ruhr University Bochum
Journal of Chemical Physics | Year: 2011

Neural networks offer an unbiased and numerically very accurate approach to represent high-dimensional ab initio potential-energy surfaces. Once constructed, neural network potentials can provide the energies and forces many orders of magnitude faster than electronic structure calculations, and thus enable molecular dynamics simulations of large systems. However, Cartesian coordinates are not a good choice to represent the atomic positions, and a transformation to symmetry functions is required. Using simple benchmark systems, the properties of several types of symmetry functions suitable for the construction of high-dimensional neural network potential-energy surfaces are discussed in detail. The symmetry functions are general and can be applied to all types of systems such as molecules, crystalline and amorphous solids, and liquids. © 2011 American Institute of Physics.

Kley R.A.,Ruhr University Bochum
The Cochrane database of systematic reviews | Year: 2013

Progressive muscle weakness is a main symptom of most hereditary and acquired muscle diseases. Creatine improves muscle performance in healthy individuals. This is an update of our 2007 Cochrane review that evaluated creatine treatment in muscle disorders. Previous updates were in 2009 and 2011. To evaluate the efficacy of creatine compared to placebo for the treatment of muscle weakness in muscle diseases. On 11 September 2012, we searched the Cochrane Neuromuscular Disease Group Specialized Register, CENTRAL (2012, Issue 9 in The Cochrane Library), MEDLINE (January 1966 to September 2012) and EMBASE (January 1980 to September 2012) for randomised controlled trials (RCTs) of creatine used to treat muscle diseases. RCTs or quasi-RCTs of creatine treatment compared to placebo in hereditary muscle diseases or idiopathic inflammatory myopathies. Two authors independently applied the selection criteria, assessed trial quality and extracted data. We obtained missing data from investigators. A total of 14 trials, including 364 randomised participants, met the selection criteria. The risk of bias was low in most studies. Only one trial had a high risk of selection, performance and detection bias. No new studies were identified at this update.Meta-analysis of six trials in muscular dystrophies including 192 participants revealed a significant increase in muscle strength in the creatine group compared to placebo, with a mean difference of 8.47%; (95% confidence intervals (CI) 3.55 to 13.38). Pooled data of four trials including 115 participants showed that a significantly higher number of participants felt better during creatine treatment compared to placebo with a risk ratio of 4.51 (95% CI 2.33 to 8.74). One trial in 37 participants with idiopathic inflammatory myopathies also showed a significant improvement in functional performance. No trial reported any clinically relevant adverse event.In metabolic myopathies, meta-analyses of three cross-over trials including 33 participants revealed no significant difference in muscle strength. One trial reported a significant deterioration of activities of daily living (mean difference 0.54 on a 1 to 10 scale; 95% CI 0.14 to 0.93) and an increase in muscle pain during high-dose creatine treatment in McArdle disease. High quality evidence from RCTs shows that short- and medium-term creatine treatment increases muscle strength in muscular dystrophies. There is also evidence that creatine improves functional performance in muscular dystrophy and idiopathic inflammatory myopathy. Creatine is well tolerated in these people. High quality but limited evidence from RCTs does not show significant improvement in muscle strength in metabolic myopathies. High-dose creatine treatment impaired activities of daily living and increased muscle pain in McArdle disease.

Rustemeier M.,Ruhr University Bochum
Alcoholism, clinical and experimental research | Year: 2012

Chronic and excessive consumption of alcohol is associated with structural, physiological, and functional changes in multiple regions of the human brain including the prefrontal cortex, the medial temporal lobe, and the structures of the reward system. The present study aimed to assess the ability of alcohol-dependent patients (ADP) to learn probabilistic stimulus-reward contingencies and to transfer the acquired knowledge to new contexts. During transfer, the relative preference to learn from positive or negative feedback was also assessed. Twenty-four recently detoxified ADP and 20 healthy controls engaged in a feedback learning task with monetary rewards. The learning performance per se and transfer performance including positive versus negative learning were examined, as well as the relationship between different learning variables and variables comprising alcohol and nicotine consumption patterns, depression, and personality traits (harm avoidance and impulsivity). Patients did not show a significant general learning deficit in the acquisition of stimulus-response-outcome associations. Fifteen healthy subjects and 13 patients reached the transfer phase, in which ADP showed generally lower performance than healthy controls. There was no specific deficit with regard to learning from positive or negative feedback. The only near-significant (negative) correlation between learning variables and drug consumption patterns, depression, and personality traits emerged for harm avoidance and positive learning in controls. Impaired transfer performance suggests that ADP had problems applying their acquired knowledge in a new context. Potential relations to dysfunctions of specific brain structures and implications of the finding for therapy are discussed. Copyright © 2012 by the Research Society on Alcoholism.

Frondel M.,Ruhr University Bochum | Frondel M.,Westphalian Institute for Economic Research
Energy Policy | Year: 2011

Estimating the degree of substitution between energy and non-energy inputs is the key for any evaluation of environmental and energy policies. Yet, given the variety of substitution elasticities, the central question arises as to which measure would be most appropriate. Apparently, Allen's elasticities of substitution have been the most-used measures in applied production analysis. In line with Frondel (2004), this paper argues that cross-price elasticities are preferable for many practical purposes. This conclusion is based on a survey of classical substitution measures, such as those from Allen, Morishima, and McFadden. The survey highlights the fact that cross-price elasticities are their essential ingredients. © 2011 Elsevier Ltd.

Shukla P.K.,Ruhr University Bochum
Physics Letters, Section A: General, Atomic and Solid State Physics | Year: 2010

Properties of electrostatic waves in ultracold neutral plasmas (UNPs) are examined, taking accounting the polarization force arising from interactions between the thermal electrons and strongly coupled ions. It is found that the polarization force reduces the phase speed of the modified dispersive ion-acoustic (M-DIA) wave in UNPs. Possibility of the ion-lattice formation in the presence of the M-DIA wave is discussed. © 2010 Elsevier B.V. All rights reserved.

Kumericki K.,University of Zagreb | Muller D.,Ruhr University Bochum
Nuclear Physics B | Year: 2010

We give a partonic interpretation for the deeply virtual Compton scattering (DVCS) measurements of the H1 and ZEUS Collaborations in the small-xB region in terms of generalized parton distributions. Thereby we have a closer look at the skewness effect, parameterization of the t-dependence, revealing the chromomagnetic pomeron, and at a model-dependent access to the anomalous gravitomagnetic moment of nucleon. We also quantify the reparameterization of generalized parton distributions resulting from the inclusion of radiative corrections up to next-to-next-to-leading order. Beyond the leading order approximation, our findings are compatible with a 'holographic' principle that would arise from a (broken) SO(2,1) symmetry. Utilizing our leading-order findings, we also perform a first model-dependent "dispersion relation" fit of HERMES and JLAB DVCS measurements. From that we extract the generalized parton distribution H on its cross-over line and predict the beam charge-spin asymmetry, measurable at COMPASS. © 2010 Elsevier B.V.

The dielectric tensor of a collision poor plasma determines all the physical properties of small-amplitude fluctuations for given initial plasma particle distribution functions, as it enters the Maxwell operator as the only plasma-specific quantity. For the important class of gyrotropic initial particle distribution functions fa(0)(p∥, p ⊥) in a uniform magnetic field, we rigorously investigate the general properties of the plasma fluctuations without specifying the explicit momentum dependence of the gyrotropic distribution function. Two alternative forms of the relativistically correct dielectric tensor are derived which differ from nonrelativistic expressions in the literature. The first standard form is expressed in terms of infinite series of Bessel functions, whereas in the second form these infinite series are calculated with the Lerche-Newberger sum rules, yielding products of Bessel functions with complex indices for the individual elements of the Maxwell operator. The second form of the dielectric tensor is well suited to simplify the tensor in the special cases of parallel wave vectors and unmagnetized plasmas. For unmagnetized plasmas it is shown that aperiodic electrostatic and transverse fluctuations can only exist in symmetric distribution functions with f (-p∥, p⊥) =f (p, p⊥). Because this includes isotropic distribution functions, the more thorough investigation of this special case reveals that no electrostatic and fluctuations with positive growth rates γ=kcS>0 exist in an isotropic unmagnetized plasma, excluding both aperiodic (with R=0) and wave-like (with R≠0) instabilities, where R= ωR / (kc) denotes the real part of the phase speed. The second form of the dielectric tensor is also most appropriate to investigate fluctuations in magnetized equal mass plasmas, such as electron-positron-pair and/or proton-antiproton plasmas. Here for arbitrary wave vector orientation the dispersion relation factorizes into three separate modes. For fluctuations with parallel wave vectors in isotropic plasmas of arbitrary composition, the electromagnetic stability of such isotropic plasma populations is proven, relativistically generalizing the known corresponding nonrelativistic theorem. © 2010 American Institute of Physics.

Bernardy K.,Ruhr University Bochum
The Cochrane database of systematic reviews | Year: 2013

Fibromyalgia (FM) is a clinically well-defined chronic condition of unknown aetiology characterized by chronic widespread pain that often co-exists with sleep disturbances, cognitive dysfunction and fatigue. Patients often report high disability levels and negative mood. Psychotherapies focus on reducing key symptoms, improving daily functioning, mood and sense of personal control over pain. To assess the benefits and harms of cognitive behavioural therapies (CBTs) for treating FM at end of treatment and at long-term (at least six months) follow-up. We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2013, Issue 8), MEDLINE (1966 to 28 August 2013), PsycINFO (1966 to 28 August 2013) and SCOPUS (1980 to 28 August 2013). We searched http://www.clinicaltrials.gov (web site of the US National Institutes of Health) and the World Health Organization Clinical Trials Registry Platform (ICTRP) (http://www.who.int/ictrp/en/) for ongoing trials (last search 28 August,2013), and the reference lists of reviewed articles. We selected randomised controlled trials of CBTs with children, adolescents and adults diagnosed with FM. The data of all included studies were extracted and the risks of bias of the studies were assessed independently by two review authors. Discrepancies were resolved by discussion. Twenty-three studies with 24 study arms with CBTs were included. A total of 2031 patients were included; 1073 patients in CBT groups and 958 patients in control groups. Only two studies were without any risk of bias. The GRADE quality of evidence of the studies was low. CBTs were superior to controls in reducing pain at end of treatment by 0.5 points on a scale of 0 to 10 (standardised mean difference (SMD) - 0.29; 95% confidence interval (CI) -0.49 to -0.17) and by 0.6 points at long-term follow-up (median 6 months) (SMD -0.40; 95% CI -0.62 to -0.17); in reducing negative mood at end of treatment by 0.7 points on a scale of 0 to 10 (SMD - 0.33; 95% CI -0.49 to -0.17) and by 1.3 points at long-term follow-up (median 6 months) (SMD -0.43; 95% CI -0.75 to -0.11); and in reducing disability at end of treatment by 0.7 points on a scale of 0 to 10 (SMD - 0.30; 95% CI -0.51 to -0.08) and at long-term follow-up (median 6 months) by 1.2 points (SMD -0.52; 95% CI -0.86 to -0.18). There was no statistically significant difference in dropout rates for any reasons between CBTs and controls (risk ratio (RR) 0.94; 95% CI 0.65 to 1.35). CBTs provided a small incremental benefit over control interventions in reducing pain, negative mood and disability at the end of treatment and at long-term follow-up. The dropout rates due to any reason did not differ between CBTs and controls.

Wu N.,Ruhr University Bochum
Transportation Research Record | Year: 2012

The critical gap is an important parameter for capacity analysis at unsignalized intersections. This parameter is stochastically distributed and cannot be obtained directly by field measurements. Thus, many procedures for estimating the critical gap have been developed. A new model for estimating critical gaps at unsignalized intersections was introduced. The new model used equilibrium of probabilities for rejected and accepted gaps and did not require presumptions regarding the distribution function of critical gaps and driver behavior. This new model has led to an unparameterized empirical distribution of critical gaps. The mathematical function of the critical gaps was not required in advance. A solution is presented to account for predefined distribution functions of critical gaps. Regression analysis is used to calibrate two distribution functions-lognormal distribution and Weibull distribution-to the empirical distribution of critical gaps. The Weibull distribution better represents the distribution of critical gaps.

Rano I.,Ruhr University Bochum
Biological Cybernetics | Year: 2012

Abstract Motion camouflage is a stealth behaviour observed both in hover-flies and in dragonflies. Existing controllers for mimicking motion camouflage generate this behaviour on an empirical basis or without considering the kinematic motion restrictions present in animal trajectories. This study summarises our formal contributions to solve the generation of motion camouflage as a non-linear optimal control problem. The dynamics of the system capture the kinematic restrictions to motion of the agents, while the performance index ensures camouflage trajectories. An extensive set of simulations support the technique, and a novel analysis of the obtained trajectories contributes to our understanding of possible mechanisms to obtain sensor based motion camouflage, for instance, in mobile robots. © The Author(s) 2012.

Masepohl B.,Ruhr University Bochum
Advances in experimental medicine and biology | Year: 2010

The vast majority of the purple nonsulfur photosynthetic bacteria are diazotrophs, but the details of the complex regulation of the nitrogen fixation process are well understood only for a few species. Here we review what is known of the well-studied Rhodobacter capsulatus, which contains two different nitrogenases, a standard Mo-nitrogenase and an alternative Fe-nitrogenase, and which has overlapping transcriptional control mechanisms with regard to the presence of fixed nitrogen, oxygen, and molybdenum as well as the capability for the post-translational control of both nitrogenases in response to ammonium. R. capsulatus has two PII proteins, GlnB and GlnK, which play key roles in nitrogenase regulation at each of three different levels: activation of transcription of the nif-specific activator NifA, the post-translational control of NifA activity, and the regulation of nitrogenase activity through either ADP-ribosylation of NifH or an ADP-ribosylation-independent pathway. We also review recent work that has led to a detailed characterization of the molybdenum transport and regulatory system in R. capsulatus that ensures activity of the Mo-nitrogenase and repression of the Fe-nitrogenase, down to extremely low levels of molybdenum.

Mosler J.,Helmholtz Center Geesthacht | Bruhns O.T.,Ruhr University Bochum
Computer Methods in Applied Mechanics and Engineering | Year: 2010

This paper is concerned with an efficient, variationally consistent, implementation for rate-independent dissipative solids at finite strain. More precisely, focus is on finite strain plasticity theory based on a multiplicative decomposition of the deformation gradient. Adopting the formalism of standard dissipative solids which allows to describe constitutive models by means of only two potentials being the Helmholtz energy and the yield function (or equivalently, a dissipation functional), finite strain plasticity is recast into an equivalent minimization problem. In contrast to previous models, the presented framework covers isotropic and kinematic hardening as well as isotropic and anisotropic elasticity and yield functions. Based on this approach a novel numerical implementation representing the main contribution of the paper is given. In sharp contrast to by now classical approaches such as the return-mapping algorithm and analogously to the theoretical part, the numerical formulation is variationally consistent, i.e., all unknown variables follow naturally from minimizing the energy of the considered system. Consequently, several different numerically efficient and robust optimization schemes can be directly employed for solving the resulting minimization problem. Extending previously published works on variational constitutive updates, the advocated model does not rely on any material symmetry and therefore, it can be applied to a broad range of different plasticity theories. As two examples, an anisotropic Hill-type and a Barlat-type model are implemented. Numerical examples demonstrate the applicability and the performance of the proposed implementation. © 2009 Elsevier B.V. All rights reserved.

Schmidt W.E.,Ruhr University Bochum
International Journal of Clinical Practice | Year: 2010

Aims: To describe Phase 1 and 2 clinical trials of liraglutide with a focus on clinical pharmacology. Key findings: In early clinical trials of liraglutide, 0.05-1.9 mg daily improved multiple aspects of glycaemic control and beta-cell function. Early trials demonstrated typical reductions in glycated haemoglobin (HbA 1c) and fasting plasma glucose (FPG) of up to 1.5% and 3.3-3.9 mmoll, respectively, at daily doses of 1.25-1.9 mg, with 45-50% of patients reaching HbA 1c < 7%. The effects of liraglutide in restoring beta-cell response to fasting and postprandial hyperglycaemia and in reinstating near-normal insulin secretion under hyperglycaemic conditions suggest a beta-cell-protective effect. By delaying gastric emptying and promoting satiety, liraglutide is weight sparing at low doses and causes clinically meaningful weight loss at higher doses and in combination with other anti-diabetes therapies with weight-modifying benefits, such as metformin. Significant improvements in other cardiovascular risk factors, including blood pressure, lipids and cardiovascular risk biomarkers, were also evident. Adverse effects of liraglutide were primarily gastrointestinal; dose-dependent nausea was the most commonly reported effect, but was typically mild-to-moderate in severity and transient in nature. Conclusions: Early clinical trials of liraglutide indicate the ability to improve glycaemic control in a glucose-dependent manner, with low risk of hypoglycaemia. Promotion of weight loss, along with improvements in multiple cardiovascular risk factors, suggests that liraglutide may offer a novel and clinically valuable approach to disease management for patients with type 2 diabetes. © 2010 Blackwell Publishing Ltd.

Nauck M.A.,Diabeteszentrum Bad Lauterberg | Kemmeries G.,Conservative Emergency Room | Holst J.J.,Copenhagen University | Meier J.J.,Ruhr University Bochum
Diabetes | Year: 2011

OBJECTIVE - Glucagon-like peptide (GLP)-1 lowers postprandial glycemia primarily through inhibition of gastric emptying. We addressed whether the GLP-1-induced deceleration of gastric emptying is subject to rapid tachyphylaxis and if so, how this would alter postprandial glucose control. RESEARCH DESIGN AND METHODS - Nine healthy volunteers (25 ± 4 years old, BMI: 24.6 ± 4.7 kg/m 2) were examined with intravenous infusion of GLP-1 (0.8 pmol · kg -1 · min -1) or placebo over 8.5 h. Two liquid mixed meals were administered at a 4-h interval. Gastric emptying was determined, and blood samples were drawn frequently. RESULTS - GLP-1 decelerated gastric emptying significantly more after the first meal compared with the second meal (P = 0.01). This was associated with reductions in pancreatic polypeptide levels (marker of vagal activation) after the first but not the second meal (P < 0.05). With GLP-1, glucose concentrations declined after the first meal but increased after the second meal (P < 0.05). The GLP-1-induced reductions in postprandial insulin and C-peptide levels were stronger during the first meal course (P < 0.05). Likewise, glucagon levels were lowered by GLP-1 after the first meal but increased after the second test meal (P < 0.05). CONCLUSIONS - The GLP-1-induced delay in gastric emptying is subject to rapid tachyphylaxis at the level of vagal nervous activation. As a consequence, postprandial glucose control by GLP-1 is attenuated after its chronic administration. © 2011 by the American Diabetes Association.

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.

Pox C.,Ruhr University Bochum
Digestive Diseases | Year: 2011

The following non-invasive stool tests for colorectal cancer (CRC) screening exist: guaiac or immunochemical fecal occult blood testing (FOBT), genetic stool tests and the M2-PK. Currently the most widely used tests are guaiac-based (gFOBT). Several randomized controlled trials have shown that gFOBT are able to achieve a reduction in CRC-related mortality. This reduction is achieved by detecting asymptomatic cancers at an early stage with a better prognosis. However, gFOBT have a low sensitivity for colorectal adenomas and are thus unlikely to be able to reduce the incidence of CRC. Furthermore, gFOBT are not specific for human blood and can be influenced by external factors. Immunochemical tests (iFOBT) only detect human blood in the stool. In two recent randomized studies from the Netherlands comparing guaiac and immunochemical tests in the asymptomatic population, iFOBT were found to detect more cancers than gFOBT. Furthermore, iFOBT were able to detect more advanced adenomas thus having the potential to be able to reduce the incidence of CRC as well as CRC-related mortality. In the recently released European CRC screening guidelines, iFOBT are considered the screening test of choice. Several questions remain however. It is currently unknown what the optimal cut-off value for an iFOBT to be considered positive should be and what the number of stool samples is that are required. Genetic stool tests detect mutations in stool that can be found in CRC. The original test testing for 21 genetic changes was found to be superior to gFOBT for the detection of cancers. However, the sensitivity was moderate (51.6%) and the sensitivity for advanced adenomas was low. In the meantime the test has been modified improving DNA extraction and reducing the number of mutations tested for as well as including a methylation marker. The efficacy of the modified test in the screening population is unknown. M2-PK is an isomer of the enzyme pyruvate kinase that is involved in glycolysis. Studies have found a good sensitivity for cancers, a low sensitivity for advanced adenomas with a specificity of around 80%. Further studies in the screening population are required. Copyright © 2011 S. Karger AG, Basel.

Rassow J.,Ruhr University Bochum | Meinecke M.,University of Gottingen | Meinecke M.,European Neuroscience Institute Gottingen
Microbes and Infection | Year: 2012

The vacuolating cytotoxin VacA, a polypeptide of about 88 kDa, is one of the major virulence factors of Helicobacter pylori. VacA essentially acts as an invasive chloride channel targeting mitochondria. The results of recent studies open a new perspective on the mechanisms by which VacA causes loss of the mitochondrial membrane potential, mitochondrial fragmentation, formation of reactive oxygen species, autophagy, cell death and gastric cancer. © 2012 Institut Pasteur.

Heidorn S.-C.,Leibniz University of Hanover | Sabellek A.,Leibniz University of Hanover | Morgenstern K.,Ruhr University Bochum
Nano Letters | Year: 2014

This study investigates the interface state electron dispersion relation between NaCl(100) islands and Ag(111) dependent upon NaCl island size. Both onset energy and effective mass are size dependent. However, these dependencies are relevant at different island sizes. We trace back this effective mass dependency to a misfit-induced strain based on atomically resolved images. Our results open up new avenues for the development of nanodevices by tuning the effective electron mass via strain of the insulating component. © 2013 American Chemical Society.

The spread of carbapenemase-producing gram-negative bacteria is one of the major challenges of the present. Since 2009, the National Reference Laboratory for gram-negative nosocomial pathogens has observed the molecular epidemiology of carbapenemases in Germany. In 2011, 1,454 referred bacterial isolates were tested for the presence of carbapenemases. Carbapenemase was found in 34.4 % of Enterobacteriaceae isolates, in 19.9 % of Pseudomonas aeruginosa isolates and in 96.3 % of Acinetobacter baumannii isolates. The most frequent carbapenemases in Enterobacteriaceae were OXA-48, KPC and VIM-1; in P. aeruginosa it was VIM-2 and in A. baumannii OXA-23.

Wascher E.,o Leibniz Research Center for Working Environment and Human Factors | Beste C.,Ruhr University Bochum
Journal of Neurophysiology | Year: 2010

The ability to notice relevant visual information has been assumed to be determined both by the relative salience of relevant information compared with distracters within a given display and by voluntary allocation of attention toward intended goals. A dominance of either of these two mechanisms in stimulus processing has been claimed by different theories. A central question in this context is to what degree and how task irrelevant signals can influence processing of target information. In the present study, participants had to detect a luminance change in various conditions among others against an irrelevant orientation change. The saliency of the latter was systematically varied and was found to be predictive for the proportion of detected information when relevant and irrelevant information were spatially separated but not when they overlapped. Weighting and competition of incoming signals was reflected in the amplitude of the N1pc component of the event-related potential. Initial orientation of attention toward the irrelevant element had to be followed by a reallocation process, reflected in an N2pc. The control of conflicting information additionally evoked a fronto-central N2 that varied with the amount of competition induced. Thus the data support models that assume that attention is a dynamic interplay of bottom-up and top-down processes that may be mediated via a common dynamic neural network. Copyright © 2010 The American Physiological Society.

Deller A.T.,Netherlands Institute for Radio Astronomy | Middelberg E.,Ruhr University Bochum
Astronomical Journal | Year: 2014

We present the description and early results of the mJy Imaging VLBA Exploration at 20 cm (mJIVE-20). mJIVE-20 is a large project on the Very Long Baseline Array which is systematically inspecting a large sample of mJy radio sources, pre-selected from the Faint Images of the Radio Sky at Twenty cm (FIRST) survey made with the Very Large Array, to identify any compact emission that may be present. The survey is being undertaken using filler time on the VLBA, which utilizes short segments scheduled in bad weather and/or with a reduced number of antennas, during which no highly rated science projects can be scheduled. The newly available multifield capability of the VLBA makes it possible for us to inspect of the order of 100 sources per hour of observing time with a 6.75σ detection sensitivity of approximately 1 mJy beam -1. The results of the mJIVE-20 survey are made publicly available as soon as the data are calibrated. After 18 months of observing, over 20,000 FIRST sources have been inspected, with 4336 very long baseline interferometry detections. These initial results suggest that within the range 1-200 mJy, fainter sources are somewhat more likely to be dominated by a very compact component than brighter sources. Over half of all arcsecond-scale mJy radio sources contain a compact component, although the fraction of sources that are dominated by milliarcsecond scale structure (where the majority of the arcsecond scale flux is recovered in the mJIVE-20 image) is smaller at around 30%-35%, increasing toward lower flux densities. Significant differences are seen depending on the optical classification of the source. Radio sources with a stellar/point-like counterpart in the Sloan Digital Sky Survey (SDSS) are more likely to be detected overall, but this detection likelihood appears to be independent of the arcsecond-scale radio flux density. The trend toward higher radio compactness for fainter sources is confined to sources that are not detected in SDSS or that have counterparts classified as galaxies. These results are consistent with a unification model of active galactic nuclei in which less luminous sources have on average slower radio jets, with lower Doppler suppression of compact core emission over a wider range of viewing angles. © 2014. The American Astronomical Society. All rights reserved..

Reske R.,TU Berlin | Mistry H.,University of Central Florida | Behafarid F.,University of Central Florida | Roldan Cuenya B.,Ruhr University Bochum | Strasser P.,TU Berlin
Journal of the American Chemical Society | Year: 2014

A study of particle size effects during the catalytic CO2 electroreduction on size-controlled Cu nanoparticles (NPs) is presented. Cu NP catalysts in the 2-15 nm mean size range were prepared, and their catalytic activity and selectivity during CO2 electroreduction were analyzed and compared to a bulk Cu electrode. A dramatic increase in the catalytic activity and selectivity for H2 and CO was observed with decreasing Cu particle size, in particular, for NPs below 5 nm. Hydrocarbon (methane and ethylene) selectivity was increasingly suppressed for nanoscale Cu surfaces. The size dependence of the surface atomic coordination of model spherical Cu particles was used to rationalize the experimental results. Changes in the population of low-coordinated surface sites and their stronger chemisorption were linked to surging H2 and CO selectivities, higher catalytic activity, and smaller hydrocarbon selectivity. The presented activity-selectivity-size relations provide novel insights in the CO2 electroreduction reaction on nanoscale surfaces. Our smallest nanoparticles (∼2 nm) enter the ab initio computationally accessible size regime, and therefore, the results obtained lend themselves well to density functional theory (DFT) evaluation and reaction mechanism verification. © 2014 American Chemical Society.

Summary: Since 1 September 2009, advance directives are regulated by law in Germany. This article discusses ethical challenges of advance directives in patients with mental disorders. Besides concrete information on the preferred medical treatment in concrete clinical situations, the mental capacity of the patient at the time of issuing the directive is essential. The .,Decisional Competence Assessment Tool for Psychiatric Advance Directives" and empirical studies from the USA on advance directives in patients with mental disorders and the assessment by the treating psychiatrists of these patient directives are discussed. Ethical conclusions are drawn for handling advance directives in psychiatric practice. © 2011 Springer-Verlag.

Todorov T.N.,Queens University of Belfast | Dundas D.,Queens University of Belfast | McEniry E.J.,Ruhr University Bochum
Physical Review B - Condensed Matter and Materials Physics | Year: 2010

A recent result for the curl of forces on ions under steady-state current in atomic wires with noninteracting electrons is extended to generalized forces on classical degrees of freedom in the presence of mean-field electron-electron screening. Current is described within a generic multiterminal picture, forces within the Ehrenfest approximation, and screening within an adiabatic, but not necessarily spatially local, mean-field picture. © 2010 The American Physical Society.

Sudden cardiac death (SCD) is one of the major problems in the western world with approximately 70,000-100,000 SCD patients (pts) in Germany and 450,000 SCD victims in the US. SCD is not caused by a single factor but is a multifactorial problem. SCD is caused by ventricular tachyarrhythmias in approximately 90% of pts, whereas SCD is caused by bradyarrhythmias in 5-10%. In 50% of SCD victims, sudden cardiac death is the first manifestation of a heart disease. There is general agreement that early defibrillation with automated external defibrillators (AED) is an effective tool to treat pts with ventricular fibrillation. Nevertheless, further stragies on cardiopulmonary resuscitation and AED therapy are necessary to improve survival of patients with cardiac arrest. © Urban & Vogel 2012.

Bruhns O.T.,Ruhr University Bochum
ZAMM Zeitschrift fur Angewandte Mathematik und Mechanik | Year: 2014

At the beginning of the last century two different types of constitutive relations to describe the complex behavior of elasto-plastic material were presented. These were the deformation theory originally developed by Hencky and the Prandtl-Reuss theory. Whereas the former provides a direct solid-like relation of stress as function of strain, the latter has been based on an additive composition of elastic and plastic parts of the increments of strains. These in turn were taken as a solid- and fluid-like combination of the de Saint-Venant/Lévy theory with an incremental form of Hooke's law. Even nowadays this Prandtl-Reuss theory is still accepted - within the restriction of small elastic deformations, i.e. it is generally stated in most textbooks on plasticity that this theory due to a number of defects can not be applied to large deformations. In the present article it is shown that this restrictive statement may be no longer true. Introducing a specific objective time derivative it could be shown that these defects disappear. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Shukla P.K.,Ruhr University Bochum | Shukla P.K.,University of California at San Diego | Avinash K.,University of Delhi
Physical Review Letters | Year: 2011

We show the existence of the liquid-vapor phase coexistence and a critical point for strongly coupled ions in ultracold neutral (UCN) plasmas. Expressions for the free energy of UCN plasmas and an equation of state for the ions are obtained in the mean field approximation. A van der Waals-like isotherm shows the existence of a critical point in UCN plasmas. Depending on the ion temperature, the ions are shown to exist in a mixed vapor-liquid phase for a range of the ion Coulomb coupling parameter Γi (defined by the ratio between the ion interaction and the ion kinetic energies), and in a strongly coupled liquid state for values of Γi above this range. The estimates of critical constants show that it may be possible to observe these phenomena in the present day UCN plasmas. © 2011 American Physical Society.

There is evidence that the leptin/ghrelin system is involved in T-cell regulation and plays a role in (auto)immune disorders such as SLE, RA and ANCA-associated vasculitides (AAVs). Here, we evaluate the genetic background of this system in WG. We screened variations in the genes encoding leptin, ghrelin and their receptors, the leptin receptor (LEPR) and the growth hormone secretagogue receptor (GHSR). Three single nucleotide polymorphisms (SNPs) in each gene region were analysed in 460 German WG cases and 878 ethnically matched healthy controls. A three-SNP haplotype of GHSR was significantly associated with WG [P = 0.0067; corrected P-value (P(c)) = 0.026; odds ratio (OR) = 1.30; 95% CI 1.08, 1.57], as was one non-synonymous SNP in LEPR (Lys656Asn, P = 0.0034; P(c) = 0.013; OR = 0.72; 95% CI 0.58, 0.90). These four SNPs were re-analysed in independent cohorts of 226 German WG cases and 519 controls. While the GHSR association was not confirmed, allele frequencies of the LEPR SNP were virtually identical to those from the initial cohorts. Analysis of this SNP in the combined WG and control panels revealed a significant association of the LEPR 656Lys allele with WG (P = 0.00032; P(c) = 0.0013; OR = 0.72; 95% CI 0.60, 0.86). Remarkably, the Lys656Asn SNP showed contrasting allele distribution in two cohorts of 108 and 88 German cases diagnosed with Churg-Strauss syndrome (CSS, combined P = 0.0067; OR = 1.41; 95% CI 1.10, 1.81), whereas identical allele frequencies were revealed when comparing British WG and microscopic polyangiitis cases. While GHSR has to be further evaluated, these data provide profound evidence for an association of the LEPR Lys656Asn SNP with AAV, resulting in opposing effects in WG and CSS.

Mecocci P.,University of Perugia | Polidori M.C.,Ruhr University Bochum
Biochimica et Biophysica Acta - Molecular Basis of Disease | Year: 2012

Alzheimer's disease (AD) is a highly disabling progressive neurodegenerative disorder characterized by a steadily growing number of patients, by the absence of a cure for the disease and by great difficulties in diagnosing in the preclinical phase. Progresses in defining the complex etiopathogenesis of AD consider oxidative stress a core aspect as far as both AD onset and progression are concerned. However, clinical trials of antioxidants in AD have brought conflicting conclusions. In this review, we report the main results of clinical trials with antioxidants in mild cognitive impairment (MCI) and AD. Although available data do not warrant the doubtless use of antioxidants in AD, they are characterized by extremely poor comparability and the absence of a substantial clinical benefit of antioxidants in AD is not disproved to date. Furthermore, the role of vascular damage that contributes to oxidative stress in AD should be addressed in testing antioxidant treatments. This article is part of a Special Issue entitled: Antioxidants and Antioxidant Treatment in Disease. © 2011 Elsevier B.V.

Abrahamsen H.,University of Oslo | Stenmark H.,University of Oslo | Platta H.W.,Ruhr University Bochum
FEBS Letters | Year: 2012

The class III phosphatidylinositol 3-kinase (PI3K-III) complex and its phosphorylated lipid product phosphatidylinositol 3-phosphate (PtdIns3P) control the three topologically related membrane-involution processes autophagy, endocytosis, and cytokinesis. The activity of the catalytic unit of PI3K-III complex, the Vacuolar sorting protein 34 (VPS34), depends on the membrane targeting unit Vacuolar sorting protein 15 (VPS15), and the tumor suppressor protein Beclin 1. It is established that the overall activity of VPS34 is positively regulated by Beclin 1, whose positive influence is further controlled through the association with a set of Beclin1 interacting components, which stimulate or inhibit VPS34. The interaction between Beclin 1 and Beclin 1-associated components are controllable and is regulated by phosphorylation in a context-dependent manner. Here, we focus on an emerging concept whereby the activity of the PI3K-III complex is controlled by ubiquitination of Beclin 1 or Beclin 1-associated molecules. In summary, at least three different ubiquitin ligases can affect the positive regulatory function of Beclin 1 towards VPS34, suggesting that ubiquitination is an important and physiologically relevant event in tuning the tumor suppressor function of Beclin 1. © 2012 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Burkhard Dick H.,Ruhr University Bochum
European Journal of Ophthalmology | Year: 2012

Purpose. Clinical outcomes of biaxial microincision versus coaxial small incision cataract surgery were compared in a prospective, controlled, paired-eye clinical study. Methods. A total of 84 eyes of 42 patients underwent cataract surgery using the biaxial microincision (B-MICS) technique in either the right or left eye. The fellow eye was to undergo cataract surgery using the standard coaxial small incision (SICS) technique. All surgeries were performed using the Stellaris Vision Enhancement System and all eyes were implanted with an aspheric microincision intraocular lens (IOL). The 1.2-mm B-MICS incision was widened to 1.8 mm for IOL insertion. The main outcome measure was the change from baseline best-corrected visual acuity (BCVA). Secondary outcome measures were uncorrected visual acuity (UCVA), surgically induced astigmatism (SIA), manifest subjective refraction in spherical equivalent (MRSE), absolute phacoemulsification time (APT), effective phacoemulsification time (EPT), mean phacoemulsification power, and endothelial cell count (ECC). Follow-up was at 1 day, 3 days, 1 week, and 2 months. Results. The treatment groups did not differ in baseline characteristics. Improvement in BCVA over baseline logarithm of the minimum angle of resolution (logMAR) was statistically significantly greater with B-MICS than SICS at 1 day (B-MICS -0.1, SICS -0.05; 95% CI -0.26 to -0.05, p=0.005). Mean improvement in UCVA from baseline was greater with B-MICS at 1 day (B-MICS -0.33, SICS -0.12; 95% CI -0.35 to -0.10, p=0.001), 3 days (B-MICS -0.39, SICS -0.26; 95% CI -0.22 to -0.02, p=0.022), 1 week (B-MICS -0.44, SICS -0.33; 95% CI -0.20 to -0.009, p=0.033), and 2 months (B-MICS -0.47, SICS 0.38; 95% CI -0.19 to +0.002, p =0.054). At 2 months, SIA was significantly lower with B-MICS than SICS (B-MICS 0.70 D, SICS 0.89 D; 95% CI -0.39 to -0.1, p=0.045), as was endothelial cell loss (B-MICS -1.4%, SICS -7.8%; p=0.05). The EPT was lower with B-MICS (B-MICS 1.60 s, SICS 2.80 s; 95% CI -1.68 to -0.77, p<0.001) with no difference in mean phaco power. Conclusions. Compared to the standard small incision technique, B-MICS showed earlier improvement in BCVA, better overall UCVA, less SIA, and less endothelial cell loss. © 2012 Wichtig Editore.

Hoffjan S.,Ruhr University Bochum
Molecular Syndromology | Year: 2012

Marfan syndrome (MFS) is an autosomal dominant disorder of the connective tissue characterized by early development of thoracic aortic aneurysms/dissections together with symptoms of the ocular and skeletal systems. While most patients/families with a classic phenotypic expression of MFS harbour mutations in the gene encoding fibrillin-1 (FBN1), genetic studies of the recent years revealed that the clinical features, as well as the mutated genes, show a high degree of overlap between MFS and other connective tissue diseases (e.g. Loeys-Dietz syndrome, Ehlers-Danlos syndrome, familial thoracic aneurysms and dissections and others). We summarize herein the current knowledge about the wide spectrum of differential diagnoses and their genetic background as well as novel therapeutic approaches in order to provide appropriate counselling and clinical follow-up for the patients. Copyright © 2012 S. Karger AG, Basel.

Hetmanczyk G.,Ruhr University Bochum
Multidimensional Systems and Signal Processing | Year: 2010

Multidimensional wave digital algorithms for numerical integration of partial differential equations exhibit not only important robustness properties, but also a massive amount of parallelism. As the technology limit of heat dissipation stalls a further increase of clock rates, modern CPUs incorporate multiple cores for parallel computation. In this paper, a safe and efficient multithreading concept is presented to exploit the multicore architecture for multidimensional wave digital algorithms. Context switching and synchronization overhead is investigated as well as effects of unfair operating system thread scheduling due to unequal cache sharing of cores. Simulation results for the nonlinear Euler equations confirm the efficiency of the proposed setup on a 1-core, 4-core and a 2 × 4-core system. © 2009 Springer Science+Business Media, LLC.

Mussenbrock T.,Ruhr University Bochum
Contributions to Plasma Physics | Year: 2012

The highly advanced treatment of surfaces as etching and deposition is mainly enabled by the extraordinary properties of technological plasmas. The primary factors that influence these processes are the flux and the energy of various species, particularly ions, that impinge the substrate surface. These features can be theoretically described using the ion energy distribution function (IEDF). The article is intended to summarize the fundamental concepts of modeling and simulation of IEDFs from simplified models to self-consistent plasma simulations. Finally, concepts for controlling the IEDF are discussed. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Blauert J.,Ruhr University Bochum
Archives of Acoustics | Year: 2012

Psychoacoustics is traditionally based on a world model that assumes a physical world existing independently of any observer - the so-called objective world. Being exposed to this world, an observer is impinged upon by a variety of stimuli reaching his/her sensory organs. These stimuli, if physiologically adequate, may cause biological transduction and signal processing in the sensory organs and its afferent pathways in such a way that finally a specific excitation of the cortex takes place, which results in sensations to appear in the observer's perceptual world. The sensations are understood as being subjective, since they require an observer to exist. This world model - also known as (objectivistic) realism - reaches its limits when it comes to explaining more complex phenomena of perception. Thereupon, in this paper, an alternative world model is emphasized and applied to psychoacoustics, namely the perceptionist's model. Like realism, perceptionism has a long tradition in epistemology. It appears to be suitable to improve our understanding of perceptual organization. Copyright © 2012 by PAN - IPPT.

Junker P.,Ruhr University Bochum
International Journal for Numerical Methods in Engineering | Year: 2014

SUMMARY: A micromechanical model for polycrystalline shape memory alloys (SMAs) was introduced in a series of papers by Hackl and coauthors. In order to model the polycrystalline aspect, they assumed a specific set of orientation distribution functions that had to be resolved with high numerical effort. Although this model displays interesting aspects, its use to simulate macroscopic specimens is problematic due to the long calculation time.In this paper, we present a new approach to modeling and simulation of polycrystalline SMAs that is based on parameterization of a class of orientation distribution functions by using only a few parameters. A variational concept is applied to derive evolution equations for these parameters. The resultant material model drastically reduces the calculation time and may thus provide an approach to efficient micromechanical simulation of specimens that are of engineering interest.This study presents a variety of different numerical examples, such as pseudoelastic and pseudoplastic material behavior for CuAlNi and NiTi SMAs, to demonstrate the broad applicability of the material model. The numerical benefit of the presented modeling approach is demonstrated by comparative calculations of the new model versus the previous model. © 2014 John Wiley & Sons, Ltd.

Braun J.,Ruhr University Bochum | Sieper J.,Franklin University
Rheumatic Disease Clinics of North America | Year: 2012

The concepts for classification, diagnosis and referral of patients with axial spondyloarthitis differ, although they of course basically relate to the same disease. While classification criteria and referral strategies concentrate largely on patients with chronic back pain with an age at onset before 45 years, the rheumatologist can make a diagnosis of axial SpA in patients with late onset or in patients with back pain for only some weeks if other items are fulfilled. Early recognition of patients with axial SpA is important to establish the diagnosis, potentially start therapeutic interventions and avoid unnecessary health care procedures. © 2012.

Urinary biomarkers have the potential to improve the early detection of bladder cancer. Most of the various known markers, however, have only been evaluated in studies with cross-sectional design. For proper validation a longitudinal design would be preferable. We used the prospective study UroScreen to evaluate survivin, a potential biomarker that has multiple functions in carcinogenesis. Survivin was analyzed in 5,716 urine samples from 1,540 chemical workers previously exposed to aromatic amines. The workers participated in a surveillance program with yearly examinations between 2003 and 2010. RNA was extracted from urinary cells and survivin was determined by Real-Time PCR. During the study, 19 bladder tumors were detected. Multivariate generalized estimation equation (GEE) models showed that β-actin, representing RNA yield and quality, had the strongest influence on survivin positivity. Inflammation, hematuria and smoking did not confound the results. Survivin had a sensitivity of 21.1% for all and 36.4% for high-grade tumors. Specificity was 97.5%, the positive predictive value (PPV) 9.5%, and the negative predictive value (NPV) 99.0%. In this prospective and so far largest study on survivin, the marker showed a good NPV and specificity but a low PPV and sensitivity. This was partly due to the low number of cases, which limits the validity of the results. Compliance, urine quality, problems with the assay, and mRNA stability influenced the performance of survivin. However, most issues could be addressed with a more reliable assay in the future. One important finding is that survivin was not influenced by confounders like inflammation and exhibited a relatively low number of false-positives. Therefore, despite the low sensitivity, survivin may still be considered as a component of a multimarker panel.

Leichert L.I.,Ruhr University Bochum
Proteomics | Year: 2011

Protein quality control is an essential process in all living organisms. A network of folding helper proteins and proteases ushers proteins into their native conformation, safeguards their structure under adverse environmental conditions, and, if all else fails, degrades proteins at the end of their life time. Escherichia coli is a versatile model organism used in the analysis of fundamental cellular processes. Much of what we know about protein quality control has been discovered in this microorganism. In the investigation of the mode of action, regulation and substrate specificity of chaperones, thiol-disulfide isomerases and proteases, proteomic methods have been playing a key role. Here, we provide a condensed overview about the protein quality control network in E. coli and the remarkable contributions of proteomics to our current knowledge. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Tautz R.C.,Ruhr University Bochum
Computer Physics Communications | Year: 2010

A new Monte Carlo code is presented that simulates the scattering processes of energetic particles in turbulent magnetic fields. The growing number of analytical models for anisotropic turbulence geometries gives rise to the need of fast and adaptable simulation codes that, in order to be able to judge the accuracy of the results, calculate the estimated mean errors of the transport parameters. Furthermore, the need to understand the interplay of scattering in anisotropic large-scale (such as the solar magnetic field) and turbulent (such as the Maltese cross-like structured solar wind turbulence) magnetic fields is accounted for with the calculation of the off-diagonal elements of the diffusion tensor. © 2009 Elsevier B.V. All rights reserved.

Funke K.,Ruhr University Bochum | Benali A.,University of Tubingen
Journal of Physiology | Year: 2011

Transcranial magnetic stimulation (TMS) has become a popular method to non-invasively stimulate the human brain. The opportunity to modify cortical excitability with repetitive stimulation (rTMS) has especially gained interest for its therapeutic potential. However, details of the cellular mechanisms of the effects of rTMS are scarce. Currently favoured are long-term changes in the efficiency of excitatory synaptic transmission, with low-frequency rTMS depressing it, but high-frequency rTMS augmenting. Only recently has modulation of cortical inhibition been considered as an alternative way to explain lasting changes in cortical excitability induced by rTMS. Adequate animal models help to highlight stimulation-induced changes in cellular processes which are not assessable in human rTMS studies. In this review article, we summarize findings obtained with our rat models which indicate that distinct inhibitory cell classes, like the fast-spiking cells characterized by parvalbumin expression, are most sensitive to certain stimulation protocols, e.g. intermittent theta burst stimulation. We discuss how our findings can support the recently suggested models of gating and homeostatic plasticity as possible mechanisms of rTMS-induced changes in cortical excitability. © 2011 The Authors. Journal compilation © 2011 The Physiological Society.

Sander W.,Ruhr University Bochum
Israel Journal of Chemistry | Year: 2016

Physical organic chemistry plays a unifying role in chemistry by combining a large variety of experimental and theoretical techniques to create simplified, intuitively understandable concepts of chemical processes. The concept of "antiaromaticity" is used to demonstrate how complex experiments may result in general models that allow chemists to predict the chemical and physical properties of difficult to access molecules and even of transition states. Cyclooctatetraene and the fluorenyl cation are used as examples to illustrate some working methods of physical organic chemistry. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Kohl M.,Ruhr University Bochum
Methods in molecular biology (Clifton, N.J.) | Year: 2011

Substantial progress has been made in the field of "omics" research (e.g., Genomics, Transcriptomics, Proteomics, and Metabolomics), leading to a vast amount of biological data. In order to represent large biological data sets in an easily interpretable manner, this information is frequently visualized as graphs, i.e., a set of nodes and edges. Nodes are representations of biological molecules and edges connect the nodes depicting some kind of relationship. Obviously, there is a high demand for computer-based assistance for both visualization and analysis of biological data, which are often heterogeneous and retrieved from different sources. This chapter focuses on software tools that assist in visual exploration and analysis of biological networks. Global requirements for such programs are discussed. Utilization of visualization software is exemplified using the widely used Cytoscape tool. Additional information about the use of Cytoscape is provided in the Notes section. Furthermore, special features of alternative software tools are highlighted in order to assist researchers in the choice of an adequate program for their specific requirements.

Turewicz M.,Ruhr University Bochum
Methods in molecular biology (Clifton, N.J.) | Year: 2011

This chapter describes Mass Spectrometry Markup Language (mzML), an XML-based and vendor-neutral standard data format for storage and exchange of mass spectrometer output like raw spectra and peak lists. It is intended to replace its two precursor data formats (mzData and mzXML), which had been developed independently a few years earlier. Hence, with the release of mzML, the problem of having two different formats for the same purposes is solved, and with it the duplicated effort of maintaining and supporting two data formats. The new format has been developed by a broad-based consortium of major instrument vendors, software vendors, and academic researchers under the aegis of the Human Proteome Organisation (HUPO), Proteomics Standards Initiative (PSI), with full participation of the main developers of the precursor formats. This comprehensive approach helped mzML to become a generally accepted standard. Furthermore, the collaborative development insured that mzML has adopted the best features of its precursor formats. In this chapter, we discuss mzML's development history, its design principles and use cases, as well as its main building components. We also present the available documentation, an example file, and validation software for mzML.

Eisenacher M.,Ruhr University Bochum
Methods in molecular biology (Clifton, N.J.) | Year: 2011

To deal with the data flood of current mass spectrometry methods, standard data formats are needed. The Proteomics Standards Initiative (PSI) of the Human Proteome Organisation (HUPO) develops open storage and transfer standards for and with the community. The Proteomics Informatics work group of the PSI has recently released an XML-based format to store the parameters and results of spectrum identification algorithms (the so-called search engines), which identify peptides and/or proteins from mass spectra. Here, this format called "mzIdentML" is described by giving principle design concepts and presenting examples of important use cases.

Rosenkranz P.,University of Hohenheim | Aumeier P.,Ruhr University Bochum | Ziegelmann B.,University of Hohenheim
Journal of Invertebrate Pathology | Year: 2010

The ectoparasitic honey bee mite Varroa destructor was originally confined to the Eastern honey bee Apis cerana. After a shift to the new host Apis mellifera during the first half of the last century, the parasite dispersed world wide and is currently considered the major threat for apiculture. The damage caused by Varroosis is thought to be a crucial driver for the periodical colony losses in Europe and the USA and regular Varroa treatments are essential in these countries. Therefore, Varroa research not only deals with a fascinating host-parasite relationship but also has a responsibility to find sustainable solutions for the beekeeping. This review provides a survey of the current knowledge in the main fields of Varroa research including the biology of the mite, damage to the host, host tolerance, tolerance breeding and Varroa treatment. We first present a general view on the functional morphology and on the biology of the Varroa mite with special emphasis on host-parasite interactions during reproduction of the female mite. The pathology section describes host damage at the individual and colony level including the problem of transmission of secondary infections by the mite. Knowledge of both the biology and the pathology of Varroa mites is essential for understanding possible tolerance mechanisms in the honey bee host. We comment on the few examples of natural tolerance in A. mellifera and evaluate recent approaches to the selection of Varroa tolerant honey bees. Finally, an extensive listing and critical evaluation of chemical and biological methods of Varroa treatments is given. This compilation of present-day knowledge on Varroa honey bee interactions emphasizes that we are still far from a solution for Varroa infestation and that, therefore, further research on mite biology, tolerance breeding, and Varroa treatment is urgently needed. © 2009 Elsevier Inc. All rights reserved.

Yamamoto M.,University of Tokyo | Takada S.,University of Tokyo | Bauerle C.,University of Tokyo | Bauerle C.,CNRS Neel Institute | And 4 more authors.
Nature Nanotechnology | Year: 2012

Solid-state approaches to quantum information technology are attractive because they are scalable. The coherent transport of quantum information over large distances is a requirement for any practical quantum computer and has been demonstrated by coupling super-conducting qubits to photons. Single electrons have also been transferred between distant quantum dots in times shorter than their spin coherence time. However, until now, there have been no demonstrations of scalable 'flying qubit' architectures - systems in which it is possible to perform quantum operations on qubits while they are being coherently transferred - in solid-state systems. These architectures allow for control over qubit separation and for non-local entanglement, which makes them more amenable to integration and scaling than static qubit approaches. Here, we report the transport and manipulation of qubits over distances of 6 μm within 40 ps, in an Aharonov - Bohm ring connected to two-channel wires that have a tunable tunnel coupling between channels. The flying qubit state is defined by the presence of a travelling electron in either channel of the wire, and can be controlled without a magnetic field. Our device has shorter quantum gates (< μm), longer coherence lengths (∼86 μm at 70 mK) and higher operating frequencies (∼100 GHz) than other solid-state implementations of flying qubits. © 2012 Macmillan Publishers Limited. All rights reserved.

Gold R.,Ruhr University Bochum | Wolinsky J.S.,University of Texas Health Science Center at Houston
Acta Neurologica Scandinavica | Year: 2011

Significant progress in multiple sclerosis (MS) treatment has been made over the last two decades, including the emergence of disease-modifying therapy (DMT). However, substantial unmet medical need persists and has stimulated the search for new therapeutics. Teriflunomide, one of the several oral DMTs under investigation, is a selective inhibitor of de novo pyrimidine synthesis which exerts a cytostatic effect on proliferating T- and B lymphocytes in the periphery and thus has both antiproliferative and anti-inflammatory properties. Anti-inflammatory effects have been demonstrated in rodent MS models, with reductions in macrophage and B- and T-cell infiltration in the central nervous system and preservation of myelin and oligodendrocytes. Delays in disease onset, reductions in disease relapses and improvements in clinical symptoms were also observed. A proof-of-concept clinical trial in patients with relapsing MS demonstrated that teriflunomide significantly reduced magnetic resonance imaging (MRI) activity and improved clinical endpoints, with both effects maintained with longer-term treatment. Additional studies have shown that teriflunomide can be safely added to beta interferon or glatiramer acetate therapy, with some evidence of additional improvements in MRI disease burden and clinical signs. Teriflunomide has an acceptable and manageable safety and tolerability profile. A large clinical programme is underway to further elucidate the role of teriflunomide in the treatment of MS. © 2010 John Wiley & Sons A/S.

The HUPO Brain Proteome Project (HUPO BPP) held its 15th workshop in Bochum, Germany, from April 8th to 9th, 2011 directly after the Proteomic Forum 2011 in Berlin. Like on every spring workshop, the focus was more on clinical aspects, so that especially clinicians participated in this workshop. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The newly found 'collisionally modified Bohm criterion' does not result from arbitrary definitions but from a systematic analysis of the sheath dynamics under the assumption λ D ≪ l, where λ D is the local Debye length and l the local ion gradient length. It is also not related to a point of inflection but to a removable singularity. © 2011 IOP Publishing Ltd.

Gold R.,Ruhr University Bochum | Kappos L.,University of Basel | Arnold D.L.,NeuroRx Research | Arnold D.L.,Montreal Neurological Institute | And 8 more authors.
New England Journal of Medicine | Year: 2012

Background: BG-12 (dimethyl fumarate) was shown to have antiinflammatory and cytoprotective properties in preclinical experiments and to result in significant reductions in disease activity on magnetic resonance imaging (MRI) in a phase 2, placebo-controlled study involving patients with relapsing-remitting multiple sclerosis. Methods: We conducted a randomized, double-blind, placebo-controlled phase 3 study involving patients with relapsing-remitting multiple sclerosis. Patients were randomly assigned to receive oral BG-12 at a dose of 240 mg twice daily, BG-12 at a dose of 240 mg three times daily, or placebo. The primary end point was the proportion of patients who had a relapse by 2 years. Other end points included the annualized relapse rate, the time to confirmed progression of disability, and findings on MRI. Results The estimated proportion of patients who had a relapse was significantly lower in the two BG-12 groups than in the placebo group (27% with BG-12 twice daily and 26% with BG-12 thrice daily vs. 46% with placebo, P<0.001 for both comparisons). The annualized relapse rate at 2 years was 0.17 in the twice-daily BG-12 group and 0.19 in the thrice-daily BG-12 group, as compared with 0.36 in the placebo group, representing relative reductions of 53% and 48% with the two BG-12 regimens, respectively (P<0.001 for the comparison of each BG-12 regimen with placebo). The estimated proportion of patients with confirmed progression of disability was 16% in the twicedaily BG-12 group, 18% in the thrice-daily BG-12 group, and 27% in the placebo group, with significant relative risk reductions of 38% with BG-12 twice daily (P = 0.005) and 34% with BG-12 thrice daily (P = 0.01). BG-12 also significantly reduced the number of gadolinium-enhancing lesions and of new or enlarging T 2-weighted hyperintense lesions (P<0.001 for the comparison of each BG-12 regimen with placebo). Adverse events associated with BG-12 included flushing and gastrointestinal events, such as diarrhea, nausea, and upper abdominal pain, as well as decreased lymphocyte counts and elevated liver aminotransferase levels. Conclusions: In patients with relapsing-remitting multiple sclerosis, both BG-12 regimens, as compared with placebo, significantly reduced the proportion of patients who had a relapse, the annualized relapse rate, the rate of disability progression, and the number of lesions on MRI. Copyright © 2012 Massachusetts Medical Society.

Gleason D.F.,Georgia Southern University | Hofmann D.K.,Ruhr University Bochum
Journal of Experimental Marine Biology and Ecology | Year: 2011

The life-cycle of reef-building corals, as is true for many benthic marine invertebrates, includes a planktonic larval phase that is critical to the maintenance of adult populations. Interest in understanding the biology of this larval phase has taken on a heightened sense of urgency as the unprecedented decline of reef-building corals throughout the world raises fears that the supply of sexually produced larvae may no longer be sufficient to sustain reef ecosystems. Here we provide an overview of coral larval biology by integrating advances that have been made using both physiological and ecological approaches. The primary areas addressed include 1) a brief survey of reproductive modes as well as aspects of development, including the onset of competence, 2) an analysis of the abiotic and biotic factors that affect planula larvae during dispersal and an assessment of the spatial scales over which these various parameters act, and 3) an accounting of the exogenous synthetic and tentative endogenous factors that induce larva-to-polyp transformations in vitro as well as efforts to decipher the underlying signaling pathways. We conclude that the relatively recent discovery of mass spawning events exhibited by many of the major reef-building corals throughout the Pacific and Caribbean has done much to advance our understanding of coral larval biology because it has allowed researchers to obtain gametes that can be used in a wide range of physiological and ecological studies. We also recommend the following as high priority research areas: 1) the mechanisms involved in developing metamorphic competence, 2) the synergistic effects of biotic and abiotic factors on the dispersal and settlement of coral larvae, and 3) comparative studies of the putative endogenous morphogens that orchestrate larva-to-polyp metamorphosis. © 2011 Elsevier B.V.

Schlitter J.,Ruhr University Bochum
European Physical Journal: Special Topics | Year: 2011

Activated processes from chemical reactions up to conformational transitions of large biomolecules are hampered by barriers which are overcome only by the input of some free energy of activation. Hence, the characteristic and rate-determining barrier regions are not sufficiently sampled by usual simulation techniques. Constraints on a reaction coordinate r have turned out to be a suitable means to explore difficult pathways without changing potential function, energy or temperature. For a dense sequence of values of r, the corresponding sequence of simulations provides a pathway for the process. As only one coordinate among thousands is fixed during each simulation, the pathway essentially reflects the system's internal dynamics. From mean forces the free energy profile can be calculated to obtain reaction rates and and insight in the reaction mechanism. In the last decade, theoretical tools and computing capacity have been developed to a degree where simulations give impressive qualitative insight in the processes at quantitative agreement with experiments. Here, we give an introduction to reaction pathways and coordinates, and develop the theory of free energy as the potential of mean force. We clarify the connection between mean force and constraint force which is the central quantity evaluated, and discuss the mass metric tensor correction. Well-behaved coordinates without tensor correction are considered. We discuss the theoretical background and practical implementation on the example of the reaction coordinate of targeted molecular dynamics simulation. Finally, we compare applications of constraint methods and other techniques developed for the same purpose, and discuss the limits of the approach. © 2011 EDP Sciences and Springer.

Kriecherbauer T.,Ruhr University Bochum | Krug J.,University of Cologne
Journal of Physics A: Mathematical and Theoretical | Year: 2010

These notes are based on lectures delivered by the authors at a Langeoog seminar of SFB/TR12 Symmetries and Universality in Mesoscopic Systems to a mixed audience of mathematicians and theoretical physicists. After a brief outline of the basic physical concepts of equilibrium and nonequilibrium states, the one-dimensional simple exclusion process is introduced as a paradigmatic nonequilibrium interacting particle system. The stationary measure on the ring is derived and the idea of the hydrodynamic limit is sketched. We then introduce the phenomenological Kardar-Parisi-Zhang (KPZ) equation and explain the associated universality conjecture for surface fluctuations in growth models. This is followed by a detailed exposition of a seminal paper of Johansson [59] that relates the current fluctuations of the totally asymmetric simple exclusion process (TASEP) to the Tracy-Widom distribution of random matrix theory. The implications of this result are discussed within the framework of the KPZ conjecture. © 2010 IOP Publishing Ltd.

Glasmachers T.,Ruhr University Bochum
GECCO 2013 - Proceedings of the 2013 Genetic and Evolutionary Computation Conference | Year: 2013

We propose a generic method for turning a modern, non-elitist evolution strategy with fully adaptive covariance matrix into an asynchronous algorithm. This algorithm can process the result of an evaluation of the fitness function anytime and update its search strategy, without the need to synchronize with the rest of the population. The asynchronous update builds on the recent developments of natural evolution strategies and information geometric optimization. Our algorithm improves on the usual generational scheme in two respects. Remarkably, the possibility to process fitness values immediately results in a speed-up of the sequential algorithm. Furthermore, our algorithm is much better suited for parallel processing. It allows to use more processors than offspring individuals in a meaningful way. Copyright © 2013 ACM.

Bayuseno A.P.,Ruhr University Bochum | Schmahl W.W.,Ludwig Maximilians University of Munich
Waste Management | Year: 2010

This paper investigates the changes of mineralogical composition of bottom ash in the environment. The chemical and mineralogical bulk composition was determined by X-ray fluorescence (XRF) and X-ray powder diffraction (XRPD) Rietveld method. Single bottom ash particles were investigated by optical microscopy, scanning electron microscopy with quantitative energy-dispersive X-ray microanalysis (SEM/EDX) and electron probe micro analysis (EPMA). SEM/EDX and EPMA are valuable complement to bulk analysis and provide means for rapid and sensitive multi-elemental analysis of ash particles. The fresh bottom ash consists of amorphous (>30. wt.%) and major crystalline phases (>1. wt.%) such as silicates, oxides and carbonates. The mineral assemblage of the fresh bottom ash is clearly unstable and an aging process occurs by reaction towards an equilibrium mineral phase composition in the environmental conditions. The significant decrease of anhydrite and amorphous contents was observed in the aged bottom ash, leading to the formation of ettringite, hydrocalumite and rosenhahnite under atmospheric conditions. In the water-treated sample, the calcite contents increased significantly, but ettringite was altered by the dissolution and precipitation processes in part, to produce gypsum, while the remaining part reacted with chloride to form hydrocalumite. Gypsum and other Ca based minerals may take up substantial amounts of heavy metals and subsequently control leaching behaviour of bottom ash. © 2010 Elsevier Ltd.

Le K.C.,Ruhr University Bochum
International Journal of Plasticity | Year: 2016

A three-dimensional continuum dislocation theory for single crystals containing curved dislocations is proposed. A set of governing equations and boundary conditions is derived for the true placement, plastic slips, and loop functions in equilibrium that minimize the free energy of crystal among all admissible functions, provided the resistance to dislocation motion is negligible. For the non-vanishing resistance to dislocation motion the governing equations are derived from the variational equation that includes the dissipation function. A simplified theory for small strains is also provided. An asymptotic solution is found for the two-dimensional problem of a single crystal beam deforming in single slip and simple shear. © 2015 Published by Elsevier Ltd.

Juckel G.,Ruhr University Bochum
Behavioural Brain Research | Year: 2015

Serotonin plays a major role in sensory processing especially with in the primary auditory cortex. The so-called loudness dependence of auditory evoked potentials is generated by pyramidal cells of the primary auditory cortex (LDAEP) which are modulated by serotonergic projection fibers to the main regulators of pyramidal cells, i.e. GABAergic interneurons. Therefore, there are a lot of preclinical as well as clinical proofs and hints that the LDAEP may serve as a valid indicator of synaptically released serotonin, although there are also data not supporting this relationship. This is further examplified by LDAEP data in patients with different states of schizophrenia, from prodromal to the chronic state. Hereby, a strong relationship was found between LDAEP, i.e. different serotonin levels, and the negative symptoms of these groups of patients with schizophrenia. This underlines the importance of LDAEP as indicator of central serotonergic neurotransmission and its high relevance for clinical psychiatry and psychopharmacology. © 2014 Elsevier B.V.

Trappe H.-J.,Ruhr University Bochum
Journal of Emergencies, Trauma and Shock | Year: 2010

Atrial premature beats are frequently diagnosed during pregnancy (PR); supraventricular tachycardia (SVT) (atrial tachycardia, AV-nodal reentrant tachycardia, circus movement tachycardia) is less frequently diagnosed. For acute therapy, electrical cardioversion with 50-100 J is indicated in all unstable patients (pts). In stable SVT, the initial therapy includes vagal maneuvers to terminate tachycardias. For short-term management, when vagal maneuvers fail, intravenous adenosine is the first choice drug and may safely terminate the arrhythmia. Ventricular premature beats are also frequently present during PR and benign in most of the pts; however, malignant ventricular tachyarrhythmias (sustained ventricular tachycardia [VT], ventricular flutter [VFlut] or ventricular fibrillation [VF]) may occur. Electrical cardioversion is necessary in all pts who are in hemodynamically unstable situation with life-threatening ventricular tachyarrhythmias. In hemodynamically stable pts, initial therapy with ajmaline, procainamide or lidocaine is indicated. In pts with syncopal VT, VF, VFlut or aborted sudden death, an implantable cardioverter-defibrillator is indicated. In pts with symptomatic bradycardia, a pacemaker can be implanted using echocardiography at any stage of PR. The treatment of the pregnant patient with cardiac arrhythmias requires important modifications of the standard practice of arrhythmia management. The goal of therapy is to protect the patient and fetus through delivery, after which chronic or definitive therapy can be administered.

Vladimirov A.A.,Ruhr University Bochum | Diakonov D.,RAS Petersburg Nuclear Physics Institute
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2012

We construct a well-defined lattice-regularized quantum theory formulated in terms of fundamental fermion and gauge fields, the same type of degrees of freedom as in the Standard Model. The theory is explicitly invariant under local Lorentz transformations and, in the continuum limit, under diffeomorphisms. It is suitable for describing large nonperturbative and fast-varying fluctuations of metrics. Although the quantum curved space turns out to be, on the average, flat and smooth owing to the noncompressibility of the fundamental fermions, the low-energy Einstein limit is not automatic: one needs to ensure that composite metrics fluctuations propagate to long distances as compared to the lattice spacing. One way to guarantee this is to stay at a phase transition. We develop a lattice mean-field method and find that the theory typically has several phases in the space of the dimensionless coupling constants, separated by the 2nd order phase transition surface. For example, there is a phase with a spontaneous breaking of chiral symmetry. The effective low-energy Lagrangian for the ensuing Goldstone field is explicitly diffeomorphism invariant. We expect that the Einstein gravitation is achieved at the phase transition. A bonus is that the cosmological constant is probably automatically zero. © 2012 American Physical Society.

Skodda S.,Ruhr University Bochum
Journal of the Neurological Sciences | Year: 2011

The hypokinetic dysarthria of Parkinson's disease (PD) has been defined as a multidimensional impairment leading to abnormalities in speech breathing, phonation, articulation and prosody. The aspect of prosody can be subdivided into further dimensions, as for example stress and accentuation, intonation variability and speech rate and regularity. According to available data from literature and findings of our own published studies, the present review illuminates the concept that inconstancies of speech fluency in PD are characterized by modifications of the arrangement of speech pauses and by a tendency of pace acceleration in the course of the performance. Furthermore, on the level of single utterances, Parkinsonian speakers feature significant difficulties to steadily repeat single syllables without accelerating or slowing down the pace as we were able to show in a series of published investigations. Evidence from literature and our own work justifies the hypothesis that the characteristic abnormalities in speech articulatory rate and regularity might serve as a marker of disease progression in PD. © 2011 Elsevier B.V.

Background. The new legal regulations of compulsory treatment in Germany require a change in clinical psychiatric practice as well as an ethical analysis of the consequences for those involved. Materials and methods. The new legal regulations are reported and via ethical analysis new problematic fields, such as consequences of the new law are identified and discussed in the context of psychiatry and law. Results. The main ethical identified problems are care of mentally ill with mental competence who refuse medical treatment, the different normative assessment of compulsory treatment and mechanical fixation, the ambivalent role of the conversation between psychiatrist and patient in order to change the natural will of the patient to avoid compulsory measures, the ethical consequences of questionable financial incentives in the context of compulsory treatment and the contradictive legal regulations in the field. Conclusions. The ethical analysis of the new law on compulsory treatment in Germany shows chances for improvement of clinical psychiatric practice as well as normative problematic regulations and fields of conflicts. © 2013 Springer-Verlag.

Chan A.,Ruhr University Bochum | Pirmohamed M.,University of Liverpool | Comabella M.,Center Desclerosi Multiple Of Catalonia
Annals of Neurology | Year: 2011

In neurology, as in any other clinical specialty, there is a need to develop treatment strategies that allow stratification of therapies to optimize efficacy and minimize toxicity. Pharmacogenomics is one such method for therapy optimization: it aims to elucidate the relationship between human genome sequence variation and differential drug responses. Approaches have focused on candidate approaches investigating absorption-, distribution-, metabolism, and elimination (ADME)-related genes (pharmacokinetic pathways), and potential drug targets (pharmacodynamic pathways). To date, however, only few genetic variants have been incorporated into clinical algorithms. Unfortunately, a large number of studies have thrown up contradictory results due to a number of deficiencies, including small sample sizes, inadequate phenotyping, and genotyping strategies. Thus, there still exists an urgent need to establish biomarkers that could help to select for patients with an optimal benefit to risk relationship. Here we review recent advances, and limitations, in pharmacogenomics for agents used in neuroimmunology, neurodegenerative diseases, ischemic stroke, epilepsy, and primary headaches. Further work is still required in all of these areas, which really needs to progress on several fronts, including better standardized phenotyping, appropriate sample sizes through multicenter collaborations and judicious use of new technological advances such as genome-wide approaches, next generation sequencing and systems biology. In time, this is likely to lead to improvements in the benefit-harm balance of neurological therapies, cost efficiency, and identification of new drugs. Ann Neurol 2011 Copyright © 2011 American Neurological Association.

Antczak G.,Wroclaw University | Kaminski W.,Wroclaw University | Morgenstern K.,Ruhr University Bochum
Journal of Physical Chemistry C | Year: 2014

We demonstrate that Ag adatoms are capable of stabilizing negatively charged copper-phthalocyanine (CuPc) molecules in a Ag-CuPc network at room temperature. For this aim, the structure of the Ag-CuPc coordination network at different molecule-adatom densities is investigated experimentally by scanning tunneling microscopy and theoretically by firstprinciples calculations. The islands formed at saturation adatom density, close to the source of adatoms, consist of a closed-packed layer without voids. The islands formed at lower adatom density consist of an irregular arrangement of larger entities, named subunits, mainly (CuPc)4Ag and (CuPc)6Ag2, which are interconnected in the same fashion as the CuPc molecules in the closed-packed layer. Silver adatoms in the subunits and between them differ by the number of molecules they link. The Ag-CuPc networks are stabilized, because the adsorption energy of CuPc molecules increases due to the presence of adatoms. © 2014 American Chemical Society.

Magnus C.S.,Ruhr University Bochum
International Journal of Advanced Manufacturing Technology | Year: 2016

Incremental sheet metal forming at elevated temperatures takes the approach to positively influence the forming properties of the processed material. Among others, the influenced key attributes of the final part are geometric accuracy, the usable material, and the residual stresses after forming. In the first part of this paper, a state of the art analysis of used heating methods and a thermal process model for Joule heating have already been presented. This second part describes the development of an experimental setup and shows results of forming of Ti6Al4V sheets. © 2016 Springer-Verlag London

Baedke J.,Ruhr University Bochum
Studies in History and Philosophy of Science Part C :Studies in History and Philosophy of Biological and Biomedical Sciences | Year: 2013

It seems that the reception of Conrad Hal Waddington's work never really gathered speed in mainstream biology. This paper, offering a transdisciplinary survey of approaches using his epigenetic landscape images, argues that (i) Waddington's legacy is much broader than is usually recognized-it is widespread across the life sciences (e.g. stem cell biology, developmental psychology and cultural anthropology). In addition, I will show that (ii) there exist as yet unrecognized heuristic roles, especially in model building and theory formation, which Waddington's images play within his work. These different methodological facets envisioned by Waddington are used as a natural framework to analyze and classify the manners of usage of epigenetic landscape images in post-Waddingtonian 'landscape approaches'. This evaluation of Waddington's pictorial legacy reveals that there are highly diverse lines of traditions in the life sciences, which are deeply rooted in Waddington's methodological work. © 2013 Elsevier Ltd.

Juckel G.,Ruhr University Bochum
Dialogues in Clinical Neuroscience | Year: 2016

The mesolimbic dopaminergic reward system is responsible for the negative affective symptomatology of schizophrenia, which may be related to a low dopamine tonus within the ventral striatum. The monetary incentive delay (MID) task can be used to study the response of the ventral striatum to incentive stimuli. We show that activation of the ventral striatum is low in patients with schizophrenia, and that this low activation is related to primary and secondary negative symptoms induced by neuroleptics, also known as antipsychotics. Switching from first-(typical) to second-generation (atypical) antipsychotics increased activation of the ventral striatum due to less blocking of dopamine D2 receptors. This and similar studies show that functional magnetic resonance imaging (fMRI) tasks are suitable to investigate important aspects of antipsychotic mechanisms. © 2016 AICH - Servier Research Group. All rights reserved.

Sun J.,Ruhr University Bochum | Klug D.D.,NRC Steacie Institute for Molecular Sciences | Pickard C.J.,University College London | Needs R.J.,Theory of Condensed Matter Group
Physical Review Letters | Year: 2011

We use a combination of a searching method and first-principles electronic structure calculations to predict novel structures of carbon monoxide (CO) which are energetically more stable than the known structures. The most stable forms of CO at zero pressure consist of metallic polycarbonyl chains with single and double bonds, rather than the familiar triply bonded insulating CO molecules. At pressures >2GPa the most stable phases are semiconducting and insulating singly bonded three-dimensional framework and layered structures. We also find a molecular Pbcm structure which is more stable than the R3c structure proposed previously for the observed μ phase. © 2011 American Physical Society.

Bakulev A.P.,Joint Institute for Nuclear Research | Mikhailov S.V.,Joint Institute for Nuclear Research | Pimikov A.V.,Joint Institute for Nuclear Research | Stefanis N.G.,Ruhr University Bochum
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2011

We perform a detailed analysis of all existing data (CELLO, CLEO, BABAR) on the pion-photon transition form factor by means of light-cone sum rules in which we include the next-to-leading order QCD radiative corrections and the twist-four contributions. The next-to-next-to-leading order radiative correction together with the twist-six contribution are also taken into account in terms of theoretical uncertainties. Keeping only the first two Gegenbauer coefficients a2 and a4, we show that the 1σ error ellipse of all data up to 9GeV2 greatly overlaps with the set of pion distribution amplitudes obtained from nonlocal QCD sum rules-within the range of uncertainties due to twist-four. This remains valid also for the projection of the 1σ error ellipsoid on the (a2,a4) plane when including a 6. We argue that it is not possible to accommodate the high-Q2 tail of the BABAR data with the same accuracy, despite opposite claims by other authors, and conclude that the BABAR data still pose a challenge to QCD. © 2011 American Physical Society.

Voss B.,Albert Ludwigs University of Freiburg | Hess W.R.,Albert Ludwigs University of Freiburg | Leichert L.I.,Ruhr University Bochum
Molecular Microbiology | Year: 2011

Wounded plants activate a complex defence programme in response to Agrobacterium tumefaciens. They synthesize the non-proteinogenic amino acid γ-aminobutyric acid (GABA), which stimulates degradation of the quorum sensing signal N-(3-oxo-octanoyl) homoserine lactone. GABA is transported into A. tumefaciens via an ABC transporter dependent on the periplasmic binding protein Atu2422. We demonstrate that expression of atu2422 and two other ABC transporter genes is downregulated by the conserved small RNA (sRNA) AbcR1 (for ABC regulator). AbcR1 is encoded in tandem with another sRNA, which is similar in sequence and structure. Both sRNAs accumulate during stationary phase but only the absence of AbcR1 resulted in significant accumulation of Atu2422 and increased GABA import. AbcR1 inhibits initiation of atu2422 translation by masking its Shine-Dalgarno sequence and thereby reduces stability of the atu2422 transcript. It is the first described bacterial sRNA that controls uptake of a plant-generated signalling molecule. Given that similar sRNAs and ABC transporter genes are present in various Rhizobiaceae and in Brucella, it is likely that such sRNA-mediated control impacts a number of host-microbe interactions. © 2011 Blackwell Publishing Ltd.

Conrad-Hengerer I.,Ruhr University Bochum
Journal of cataract and refractive surgery | Year: 2012

To compare the effect of different fragmentation softening grids in femtosecond laser-assisted cataract surgery on effective phacoemulsification time (EPT). Ruhr University Eye Clinic, Bochum, Germany. Prospective randomized clinical trial. The study evaluated the feasibility of using a femtosecond laser (Catalys Precision Laser System) to perform capsulotomy and lens fragmentation in the treatment of patients with senile cataract. Patients were evaluated preoperatively with the Lens Opacities Classification System III (LOCS III). Patients had laser refractive cataract surgery with 350 μm fragmentation grids or with 500 μm fragmentation grids. Both groups had phacoemulsification using pulsed ultrasound energy, and the EPT was evaluated. Eighty patients were treated with 350 μm fragmentation grids and 80 patients with 500 μm fragmentation grids. The mean preoperative LOCS III grade was 3.7 ± 0.8 (SD) in the 350 μm group and 3.5 ± 0.8 in the 500 μm group. The mean laser treatment time was 66.4 ± 14.4 seconds in the 350 μm group and 52.8 ± 11.9 seconds in the 500 μm grid group and the mean EPT, 0.03 ± 0.05 seconds and 0.21 ± 0.26 seconds, respectively. The use of the femtosecond laser-assisted system in cataract surgery with 350 μm grid softening led to a statistically significant lower EPT than the 500 μm grid. Dr. Dick is a member of the medical advisory board of Optimedica Corp. No other author has a financial or proprietary interest in any material or method mentioned. Copyright © 2012 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Sitnov M.I.,Johns Hopkins University | Schindler K.,Ruhr University Bochum
Geophysical Research Letters | Year: 2010

The sufficient stability criterion of the collisionless ion tearing mode in the magnetotail current sheet, which was first obtained by Lembege and Pellat in 1982, is considered. For many conventional 2D current sheet equilibria, this criterion is satisfied within the WKB approximation, which is commonly interpreted as stability of those equilibria with respect to tearing. However, this is not necessarily the case for equilibria with more than two characteristic spatial scales. An example for substantial tearing destabilization of an equilibrium with accumulation of the magnetic flux at the tailward end of a thin current sheet is presented. Similar equilibria are reported in Geotail and THEMIS observations prior to onsets of magnetospheric substorms and dipolarization fronts associated with bursty bulk flows. Copyright 2010 by the American Geophysical Union.

Klinge S.,Ruhr University Bochum
Biomechanics and Modeling in Mechanobiology | Year: 2013

This contribution deals with the application of the inverse homogenization method to the determination of geometrical properties of cancellous bone. The approach represents a combination of an extended version of the Marquardt-Levenberg method with the multiscale finite element method. The former belongs to the group of gradient-based optimization strategies, while the latter is a numerical homogenization method, suitable for the modeling of materials with a highly heterogeneous microstructure. The extension of the Marquardt-Levenberg method is concerned with the selection strategy for distinguishing the global minimum from the plethora of local minima. Within the numerical examples, the bone is modeled as a biphasic viscoelastic medium and three different representative volume elements are taken into consideration. Different models enable the simulation of the bone either as a purely isotropic or as a transversally anisotropic medium. Main geometrical properties of trabeculae are determined from data on effective shear modulus but alternative schemes are also possible. © 2012 Springer-Verlag.

Bjerg L.,University of Aarhus | Madsen G.K.H.,Ruhr University Bochum | Iversen B.B.,University of Aarhus
Chemistry of Materials | Year: 2012

Several efficient thermoelectric materials have been found among the ternary Zintl antimonides. If the band structure is highly asymmetric around the band gap, the efficiency as either n- or p-type may differ significantly. The Zintl antimonides have generally been found to be p-type. Surprisingly, this also holds true for the narrow band gap binary ZnSb and Zn 4Sb 3. Using ab initio calculations, we investigate intrinsic point defects in ZnSb as a possible origin of the p-type conductivity. Only Zn vacancies are found to be present in significant amounts at room temperature. The low formation energy of negatively charged Zn defects pins the electronic chemical potential to the lower part of the band gap leading to intrinsic ZnSb being p-type. We discuss this finding as a general explanation of p-type conductivity in Zintl antimonides, and how to overcome the doping limits in these materials. © 2012 American Chemical Society.

Over the last few years, incretin-based therapies have emerged as important agents in the treatment of type 2 diabetes (T2D). These agents exert their effect via the incretin system, specifically targeting the receptor for the incretin hormone glucagon-like peptide 1 (GLP-1), which is partly responsible for augmenting glucose-dependent insulin secretion in response to nutrient intake (the 'incretin effect'). In patients with T2D, pharmacological doses/concentrations of GLP-1 can compensate for the inability of diabetic β cells to respond to the main incretin hormone glucose-dependent insulinotropic polypeptide, and this is therefore a suitable parent compound for incretin-based glucose-lowering medications. Two classes of incretin-based therapies are available: GLP-1 receptor agonists (GLP-1RAs) and dipeptidyl peptidase-4 (DPP-4) inhibitors. GLP-1RAs promote GLP-1 receptor (GLP-1R) signalling by providing GLP-1R stimulation through 'incretin mimetics' circulating at pharmacological concentrations, whereas DPP-4 inhibitors prevent the degradation of endogenously released GLP-1. Both agents produce reductions in plasma glucose and, as a result of their glucose-dependent mode of action, this is associated with low rates of hypoglycaemia; however, there are distinct modes of action resulting in differing efficacy and tolerability profiles. Furthermore, as their actions are not restricted to stimulating insulin secretion, these agents have also been associated with additional non-glycaemic benefits such as weight loss, improvements in β-cell function and cardiovascular risk markers. These attributes have made incretin therapies attractive treatments for the management of T2D and have presented physicians with an opportunity to tailor treatment plans. This review endeavours to outline the commonalities and differences among incretin-based therapies and to provide guidance regarding agents most suitable for treating T2D in individual patients. © 2016 John Wiley & Sons Ltd.

Raulf M.,Ruhr University Bochum
Current Opinion in Allergy and Clinical Immunology | Year: 2016

Purpose of review Rapid developments have been seen in molecular allergy diagnosis, based on the detection and quantification of specific IgE to single allergens. This review summarizes and discusses studies on allergen component analysis as a tool in the diagnosis of occupational allergy. Recent findings More than 400 agents are identified as sensitizers of occupational asthma, but only very few are characterized on the molecular level and available for routine diagnosis. Baker's asthma is one of the most frequently occurring forms of occupational asthma caused by workplace-related inhalation of cereal flour mainly wheat. Wheat sensitization profiles of bakers show great interindividual variability and no wheat allergen could be classified as the major allergen. Component-resolved diagnosis is a useful tool for diagnosing natural rubber latex (NRL) allergy. In cases with unexpected high-latex IgE but without clinical symptoms application of crossreactive carbohydrate determinants are helpful to clarify the cause of IgE binding. Summary Latex is an excellent model for component-resolved diagnosis and demonstrates well how to improve the diagnosis by using single allergens. For diagnosis of baker's asthma, a whole wheat extract is still the best option for specific IgE determination, but single wheat allergens might help to discriminate between wheatinduced food allergy, grass-pollen allergy, and baker's asthma. New diagnostic tools and platforms are promising, but further knowledge of molecules relevant for occupational asthma (as in wood dust allergens, enzymes, laboratory animal allergens, etc.) and for occupational hypersensitivity pneumonitis is necessary to improve and standardize the diagnostic tools. Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.

Homann H.,Ruhr University Bochum | Homann H.,University of Nice Sophia Antipolis | Bec J.,University of Nice Sophia Antipolis
Journal of Fluid Mechanics | Year: 2010

The dynamics of neutrally buoyant particles transported by a turbulent flow is investigated for spherical particles with radii of the order of the Kolmogorov dissipative scale or larger. The pseudo-penalization spectral method that has been proposed by Pasquetti et al. (Appl. Numer. Math., vol. 58, 2008, pp. 946-954) is adapted to integrate numerically the simultaneous dynamics of the particle and of the fluid. Such a method gives a unique handle on the limit of validity of point-particle approximations, which are generally used in applicative situations. Analytical predictions based on such models are compared to result of very well-resolved direct numerical simulations. Evidence is obtained that Faxén corrections reproduce dominant finite-size effects on velocity and acceleration fluctuations for particle diameters up to four times the Kolmogorov scale. The dynamics of particles with larger diameters is consistent with predictions obtained from dimensional analysis. © 2010 Cambridge University Press.

Fumaric acid esters (FAE) are beneficial in the treatment of psoriasis. However, about a third of psoriasis patients do not respond to FAE. We aimed to determine whether glutathione-S-transferase (GST) M1 and GSTP1 polymorphisms are associated with treatment outcome in psoriasis patients treated with FAE. We studied 84 psoriasis patients who were treated with FAE for 3 months. FAE nonresponders were defined as having psoriasis area and severity improvement index less than 50% after 3-month therapy. GSTM1 genotyping for gene deletion and GSTP1 exon 5 105 Ile→Val polymorphisms were assessed using a high-resolution melting analysis. A dropout rate of 23.8% (20/84) was found; 25% (16/64) were FAE nonresponders. We observed 42 (84/50%) patients with G 9STM1*0 homozygous alleles and 42 (84/50%) patients with one or two active GSTM1 alleles. The Ile/Ile GSTP1 genotype was observed in 37 (84/44%), the Ile/Val GSTP1 genotype in 38 (84/45.2%) patients and the Val/Val GSTP1 genotype in nine (84/10.7%) patients. There was no significant (P>0.05) association between the GST genotypes assessed and the frequency FAE responder status, except for the Val/Val GSTP1 polymorphism, which was a significant (overall model fit; P=0.0012) predictor for nonresponders with an odds ratio of 43.4 (95% confidence interval: 4.2–511.1). The coefficient of regression was 3.9, with a SE of 1.2 as assessed by logistic regression analysis (P=0.0017). The Val/Val GSTP1 polymorphism predicts nonresponders in FAE treatment of psoriasis patients and may therefore serve as a biomarker that enables a laboratory-based pretreatment selection of patients. Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.

Costabel U.,University of Duisburg - Essen | Bonella F.,University of Duisburg - Essen | Guzman J.,Ruhr University Bochum
Clinics in Chest Medicine | Year: 2012

Hypersensitivity pneumonitis (HP) is a complex syndrome caused by the inhalation of environmental antigens. Chronic HP may mimic other fibrotic lung diseases, such as idiopathic pulmonary fibrosis. Recognition of the antigen is important for diagnosis; avoidance of further exposure is critical for treatment. Fibrosis on biopsy or high-resolution computed tomography is a predictor of increased mortality. Additional research is needed to understand why the disease develops only in a minority of exposed individuals and why cases of chronic HP may progress without further antigen exposure. © 2012 Elsevier Inc.

Thomas M.F.H.,University of Manchester | Bodin S.,Ruhr University Bochum
Marine and Petroleum Geology | Year: 2013

Large scale channel systems are commonly imaged using seismic data and classified hierarchically. Where exposed at outcrop, similar scale ancient channel systems provide an opportunity to investigate subseismic scale architectures, produced for example through short duration autocyclic processes, and assess how they contribute to larger seismic scale architectures. In this study, a seismic scale slope-confined channel system from the Numidian Flysch Formation of northern Sicily is described using a hierarchical classification scheme. The channel system is 5.7 km wide and is organised within 3 hierarchical levels, comprising; 2 channel complex sets, 16 channel complexes, and >30 channel elements. channel complexes are mappable bodies and reach 500 m wide and 90 m thick. Slope confined sinuous channel complexes contain stacked channel elements which show a progression of incision and bypass to fill with massive sandstones interspersed with graded turbidite deposits. Flows are interpreted to predominantly deposit during quasi-steady flow conditions although flow non-uniformity produced beds with complex grading patterns. Lateral expansion of channel elements produced terracing within the complex margin and had the capacity to alter flow rheology through incorporation of large mud volumes. Sinuosity of channel element thalwegs and offset stacking produced asymmetric channel complexes with heterogeneous internal architectures and lithofacies distributions. Both channel complexes and channel elements thicken with younging indicating increased entrenchment through allocyclic forcing. The frequency distribution of channel-element thicknesses also shows a positive skew centred around 12 m as with published data global datasets. We question whether this distribution similarity may result from a fundamental process at the channel-element scale such as substrate armouring through coarse grained sedimentary deposits exceeding the capacity limits of transiting flows. The use of a hierarchical classification scheme therefore highlights the importance of subseismic scale processes on mappable architectures. The quantification of specific hierarchical elements also allows the role of allocyclic forcing to be investigated in an area of complex palaeogeography. © 2012 Elsevier Ltd.

Glasmachers T.,Dalle Molle Institute for Artificial Intelligence | Igel C.,Ruhr University Bochum
IEEE Transactions on Pattern Analysis and Machine Intelligence | Year: 2010

Adapting the hyperparameters of support vector machines (SVMs) is a challenging model selection problem, especially when flexible kernels are to be adapted and data are scarce. We present a coherent framework for regularized model selection of 1-norm soft margin SVMs for binary classification. It is proposed to use gradient-ascent on a likelihood function of the hyperparameters. The likelihood function is based on logistic regression for robustly estimating the class conditional probabilities and can be computed efficiently. Overfitting is an important issue in SVM model selection and can be addressed in our framework by incorporating suitable prior distributions over the hyperparameters. We show empirically that gradient-based optimization of the likelihood function is able to adapt multiple kernel parameters and leads to better models than four concurrent state-of-the-art methods. © 2010 IEEE.

Plumere N.,Ruhr University Bochum
Analytical and Bioanalytical Chemistry | Year: 2013

Bioelectroanalytical procedures based on cathodic processes are often subject to interference from dissolved oxygen. At the potentials applied for analyte detection, oxygen reduction may occur directly at the electrode or may be catalyzed by the electron mediators or the sensing enzyme of the biosensor. These processes affect the background current and may thus result in erroneous analyte quantification. In this review, current strategies to circumvent these oxygen interferences are presented and critically assessed with respect to their compatibility for on-site monitoring with amperometric biosensing devices operating at low potential. The main strategies consist in (1) use of oxygen scavenging systems to remove dissolved oxygen from the sample, (2) design of bioelectroanalytical approaches to shift the applied potential for analyte detection to more positive values, and (3) development of electrode materials to increase the overpotential for the oxygen reduction reaction. The latest developments in these approaches have recently led to the first biosensing devices based on reductases fully compatible with on-site monitoring requirements and this opens up possibilities for their widespread application. © 2013 Springer-Verlag Berlin Heidelberg.

Calle-Vallejo F.,Leiden University | Koper M.T.M.,Leiden University | Bandarenka A.S.,Ruhr University Bochum
Chemical Society Reviews | Year: 2013

During the past decade, electrocatalysis has attracted significant attention primarily due to the increased interest in the development of new generations of devices for electrochemical energy conversion. This has resulted in a progress in both fundamental understanding of the complex electrocatalytic systems and in the development of efficient synthetic schemes to tailor the surface precisely at the atomic level. One of the viable concepts in electrocatalysis is to optimise the activity through the direct engineering of the properties of the topmost layers of the surface, where the reactions take place, with monolayer and sub-monolayer amounts of metals. This forms (bi)metallic systems where the electronic structure of the active sites is optimised using the interplay between the nature and position of the atoms of solute metals at the surface. In this review, we focus on recent theoretical and experimental achievements in designing efficient (bi)metallic electrocatalysts with selective positioning of foreign atoms to form a variety of active catalytic sites at the electrode surface. We summarize recent results published in the literature and outline challenges for computational and experimental electrocatalysis to engineer active and selective catalysts using atomic layers. © 2013 The Royal Society of Chemistry.

Beste C.,Ruhr University Bochum | Dinse H.R.,Universitatsstrasse 150
Current Biology | Year: 2013

Achieving high-level skills is generally considered to require intense training, which is thought to optimally engage neuronal plasticity mechanisms. Recent work, however, suggests that intensive training may not be necessary for skill learning. Skills can be effectively acquired by a complementary approach in which the learning occurs in response to mere exposure to repetitive sensory stimulation. Such training-independent sensory learning induces lasting changes in perception and goal-directed behaviour in humans, without any explicit task training. We suggest that the effectiveness of this form of learning in different sensory domains stems from the fact that the stimulation protocols used are optimized to alter synaptic transmission and efficacy. While this approach directly links behavioural research in humans with studies on cellular plasticity, other approaches show that learning can occur even in the absence of an actual stimulus. These include learning through imagery or feedback-induced cortical activation, resulting in learning without task training. All these approaches challenge our understanding of the mechanisms that mediate learning. Apparently, humans can learn under conditions thought to be impossible a few years ago. Although the underlying mechanisms are far from being understood, training-independent sensory learning opens novel possibilities for applications aimed at augmenting human cognition. © 2013 Elsevier Ltd.

Pospech J.,Leibniz Institute for Catalysis at the University of Rostock | Fleischer I.,Leibniz Institute for Catalysis at the University of Rostock | Franke R.,Evonik Industries | Franke R.,Ruhr University Bochum | And 2 more authors.
Angewandte Chemie - International Edition | Year: 2013

Transition-metal-catalyzed hydroformylation reactions constitute one of the most powerful tools for C-C bond formation in organic synthesis and represent an outstanding example of the application of homogeneous catalysis on an industrial scale. This process allows for the straightforward conversion of inexpensive chemical feedstock into broadly applicable aldehydes, which serve as major building blocks for numerous chemical products. These products are highly valuable for the chemical industry and used as plasticizers, detergents, and surfactants on a million ton scale. Moreover, aldehydes serve as versatile chemical intermediates for the production of fine chemicals and pharmaceuticals. Currently, most of the bulk hydroformylation processes rely on rhodium-based catalysts. The increasing demand and resulting high cost of this precious metal has resulted in alternative transition-metal catalysts becoming highly desirable. The following Review summarizes the progress achieved utilizing Ru, Ir, Pd, Pt, and Fe catalysts in hydroformylation reactions. New possibilities: There is a growing awareness that organometallic complexes based on ruthenium, iridium, palladium, and even iron as the central metal offer new opportunities for catalytic hydroformylations (see scheme; TM=transition metal). Research from the past few decades is critically summarized in this Review. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Schertl H.-P.,Ruhr University Bochum | Sobolev N.V.,RAS Institute of Geology and Mineralogy
Journal of Asian Earth Sciences | Year: 2013

After the discovery of metamorphic coesite in crustal rocks from the Western Alps (Italy) and the Western gneiss region (Norway) in the mid 1980s of the last century, metamorphic diamond was observed only a few years later " in situ" in the Kokchetav Massif (Kazakhstan). Findings of such coesite- and diamond-bearing ultrahigh pressure metamorphic (UHP) rocks with protoliths formed or embedded in crustal levels and subsequently experienced PT-conditions within or even higher than the coesite stability field have dramatically changed our geodynamic view of orogenetic processes. These occurrences provide evidence that crustal rocks were subducted into mantle depths and exhumed to the surface. Recent studies even suggest continental subduction to depths exceeding 300. km. These rocks have been extensively studied and many new and important observations have been made. Thus far, more than 350 papers have been published on various aspects of Kokchetav UHP rocks.The Kokchetav Massif of northern Kazakhstan is part of one of the largest suture zones in Central Asia and contains slices of HP and UHP metamorphic rocks. Classical UHP rocks mainly occur in the Kumdy Kol, Barchi Kol and Kulet areas, and include a large variety of lithologies such as calcsilicate rocks, eclogite, gneisses, schists, marbles of various compositions, garnet-pyroxene-quartz rocks, and garnet peridotite. Most of them contain microdiamonds; some of which reach a grain size of 200μm. Most diamond grains show cuboid shapes but in rare cases, diamonds within clinozoisite gneiss from Barchi Kol occur as octahhedral form. Microdiamonds contain highly potassic fluid inclusions, as well as solid inclusions like carbonates, silicates and metal sulfides, which favour the idea of diamond formation from a C-O-H bearing fluid. Nitrogen isotope data and negative δ13C values of Kokchetav diamonds indicate a metasedimentary origin.PT-estimates of Kokchetav UHP rocks yield peak metamorphic conditions of at least 43 kbar at temperatures of about 950-1000. °C. Some zircon separates show inherited Proterozoic cores and 537-530. Ma UHP metamorphic mantle zones. Several Ar-Ar-ages on micas scatter around 529-528 and 521-517. Ma and reflect different stages of the exhumation history. Migmatization occurred during exhumation at about 526-520. Ma.Isotopic studies on calcsilicate rocks confirm a metasedimentary origin: δ18O values of garnet and clinopyroxene of a layered calcsilicate rock rule out the possibility having a primitive mantle protolith. Similar studies on eclogites indicate their basaltic protolith having experienced water-rock interaction prior to UHP metamorphism.A number of unique mineralogical findings have been made on Kokchetav UHP rocks. K-feldspar exsolutions in clinopyroxene demonstrate that potassium can be incorporated into the cpx-structure under upper mantle pressures. Other significant observations are coesite exsolutions in titanite, quartz-rods in cpx, the discovery of K-tourmaline as well as new minerals like kokchetavite, a hexagonal polymorph of K-feldspar and kumdykolite, an orthorhombic polymorph of albite.The Kokchetav UHP rocks represent a unique and challenging stomping ground for geoscientists of various disciplines. From crystallography, petrology and geochemistry to geophysics and geodynamics/geotectonics - it concerns all who are interested in the diverse metamorphic processes under upper mantle conditions. © 2012 Elsevier Ltd.

Wink R.,Ruhr University Bochum
Regional Studies | Year: 2010

Wink R. Transregional institutional learning in Europe: prerequisites, actors and limitations, Regional Studies. Transregional institutional learning has become a buzzword in European policy-making during the last decade. A theoretical concept about how to initiate, observe, and support transregional institutional learning, however, is still missing. The following paper provides a theoretical framework to explain preconditions for transregional institutional learning and investigates the potentials of three different channels for learning: multinational firms, benchmarking studies and projects, and interactive policy networks. The results show that there is not much proof for enthusiastic expectations on future learning processes, but options for European Union policies to enhance transregional learning effects. © 2010 Regional Studies Association.

Stockfleth E.,Ruhr University Bochum
Journal of the European Academy of Dermatology and Venereology | Year: 2015

The new target for the treatment of actinic keratosis (AK) is the detection and clearance of clinical and subclinical lesions across an entire sun-exposed field. This is because patients with AK have field cancerization as ultraviolet light affects the entire sun-exposed area and because it is not possible to predict which AK lesions will progress into invasive squamous cell carcinoma. To fully assess the effectiveness of field-directed therapies against the full burden of AK, a new efficacy concept has been developed which is based on the reduction in lesions from Lmax, or the maximum lesion count during treatment. This new parameter enables the efficacy of a field-directed therapy against both clinical and subclinical lesions to be assessed. Imiquimod 3.75% is a novel field-directed therapy which uniquely can detect and clear both clinical and subclinical lesions across a large sun-exposed field such as the full face or balding scalp, and so far is the only AK treatment to have had its efficacy assessed with the Lmax concept. The detection of subclinical lesions is evidenced by an increase in lesion count during each of the 2-week treatment cycles, which are separated by a 2-week treatment-free interval. The median percentage reduction in lesions from Lmax with imiquimod 3.75% is 92%, and the effective clearance of both clinical and subclinical lesions leads to sustained lesion clearance for at least 1 year. Imiquimod 3.75% has an acceptable tolerability profile. Rest periods from treatment may be taken if required to manage local skin reactions, with no loss in efficacy. In conclusion, Lmax and imiquimod 3.75% together set the new standard in the management of patients with AK. © 2014 European Academy of Dermatology and Venereology.

Steinbach I.,Ruhr University Bochum
Annual Review of Materials Research | Year: 2013

This review presents a phase-field model that is generally applicable to homogeneous and heterogeneous systems at the mesoscopic scale. Reviewed first are general aspects about first- and second-order phase transitions that need to be considered to understand the theoretical background of a phase field. The mesoscopic model equations are defined by a coarse-graining procedure from a microscopic model in the continuum limit on the atomic scale. Special emphasis is given to the question of how to separate the interface and bulk contributions to the generalized thermodynamic functional, which forms the basis of all phase-field models. Numerical aspects of the discretization are discussed at the lower scale of applicability. The model is applied to spinodal decomposition and ripening in Ag-Cu with realistic thermodynamic and kinetic data from a database. © Copyright © 2013 by Annual Reviews. All rights reserved.

Akbari-Moghanjoughi M.,Shahid Madani University of Azarbaijan | Akbari-Moghanjoughi M.,Ruhr University Bochum
Physics of Plasmas | Year: 2015

In this paper, we revisit the hydrodynamic limit of the Langmuir wave dispersion relation based on the Wigner-Poisson model in connection with that obtained directly from the original Lindhard dielectric function based on the random-phase-approximation. It is observed that the (fourth-order) expansion of the exact Lindhard dielectric constant correctly reduces to the hydrodynamic dispersion relation with an additional term of fourth-order, beside that caused by the quantum diffraction effect. It is also revealed that the generalized Lindhard dielectric theory accounts for the recently discovered Shukla-Eliasson attractive potential (SEAP). However, the expansion of the exact Lindhard static dielectric function leads to a k4 term of different magnitude than that obtained from the linearized quantum hydrodynamics model. It is shown that a correction factor of 1/9 should be included in the term arising from the quantum Bohm potential of the momentum balance equation in fluid model in order for a correct plasma dielectric response treatment. Finally, it is observed that the long-range oscillatory screening potential (Friedel oscillations) of type cos (2 k F r) / r 3, which is a consequence of the divergence of the dielectric function at point k = 2kF in a quantum plasma, arises due to the finiteness of the Fermi-wavenumber and is smeared out in the limit of very high electron number-densities, typical of white dwarfs and neutron stars. In the very low electron number-density regime, typical of semiconductors and metals, where the Friedel oscillation wavelength becomes much larger compared to the interparticle distances, the SEAP appears with a much deeper potential valley. It is remarked that the fourth-order approximate Lindhard dielectric constant approaches that of the linearized quantum hydrodynamic in the limit if very high electron number-density. By evaluation of the imaginary part of the Lindhard dielectric function, it is shown that the Landau-damping region in ω-k plane increases dramatically by increase of the electron number-density. © 2015 AIP Publishing LLC.

Gurevich E.L.,Ruhr University Bochum
Applied Surface Science | Year: 2016

Here we analyze the formation of laser-induced periodic surface structures (LIPSS) on metal surfaces upon single femtosecond laser pulses. Most of the existing models of the femtosecond LIPSS formation discuss only the appearance of a periodic modulation of the electron and ion temperatures. However the mechanism how the inhomogeneous surface temperature distribution induces the periodically-modulated surface profile under the conditions corresponding to ultrashort-pulse laser ablation is still not clear. Estimations made on the basis of different hydrodynamic instabilities allow to sort out mechanisms, which can bridge the gap between the temperature modulation and the LIPSS. The proposed theory shows that the periodic structures can be generated by single ultrashort laser pulses due to ablative instabilities. The Marangoni and Rayleigh-Bénard convection on the contrary cannot cause the LIPSS formation.

Gold R.,Ruhr University Bochum | Linker R.A.,Friedrich - Alexander - University, Erlangen - Nuremberg | Stangel M.,Hannover Medical School
Clinical Immunology | Year: 2012

Fumaric acid was originally therapeutically used in psoriasis. Several lines of evidence have demonstrated immunomodulatory but also neuroprotective effects for FAE. Clinical studies in psoriasis showed a reduction of peripheral CD4+ and CD8+ T-lymphocytes due to the ability of FAE to induce apoptosis. In vitro studies with the ester dimethylfumarate (DMF) described an inhibitory effect on nuclear factor kappa B (NF-κB)-dependent transcription of tumor necrosis factor-alpha (TNF-α) induced genes in human endothelial cells. Animal experiments in the mouse model of central nervous system demyelination, MOG-induced experimental autoimmune encephalomyelitis, revealed a clear preservation of myelin and axonal density in the plaque. Molecular studies showed that this is based on the antioxidative mechanism of action via induction of the transcription factor Nrf-2. A phase II clinical trial in relapsing-remitting multiple sclerosis (RRMS) patients with dimethylfumarate showed a significant reduction in the number of gadolinium enhancing lesions after 24. weeks. © 2011 Elsevier Inc.

Bischoff P.,Ruhr University Bochum | Rundshagen I.,Charite - Medical University of Berlin
Deutsches Arzteblatt | Year: 2011

Background: Awareness while under general anesthesia, and the later recall of what happened during surgery, can be experienced by patients as horrific events that leave lasting mental trauma behind. Patients may have both auditory and tactile perception, potentially accompanied by feelings of helplessness, inability to move, pain, and panic ranging to an acute fear of death. For some patients, the experience of awareness under anesthesia has no sequelae; for others, however, it can lead to the development of post-traumatic stress disorder, consisting of complex psychopathological phenomena such as anxiety, insomnia, nightmares, irritability, and depression possibly leading to suicidality. Methods: The literature on the subject was selectively reviewed. Results: In the absence of risk factors awareness phenomena occur in one to two per 1000 operations under general anesthesia (0.1 % to 0.2 %) and are thus classed as an occasionally occurring critical event. In children, the risk of such phenomena occurring is 8 to 10 times higher. These phenomena are due to an inadequate depth of anesthesia with incomplete unconsciousness. They can be promoted by a number of risk factors that are either patient-related (ASA class III or above, medication abuse), surgery-related (Caesarean section, emergency procedures, surgery at night), or anesthesia-related (anesthesia without benzodiazepines, use of muscle relaxants). Conclusion: Strategies for avoiding awareness phenomena under anesthesia include the training of staff to know about the problem and, specifically, the use of benzodiazepines, the avoidance of muscle relaxants if possible, and shielding the patient from excessive noise. EEG monitoring is effective but provides no guarantee against awareness. If awareness under anesthesia occurs despite these measures, the patient must be given expert, interdisciplinary treatment as soon after the event as possible in order to minimize its potential sequelae.

Rubatto D.,Australian National University | Chakraborty S.,Ruhr University Bochum | Dasgupta S.,Indian Institute of Science
Contributions to Mineralogy and Petrology | Year: 2013

The petrology and timing of crustal melting has been investigated in the migmatites of the Higher Himalayan Crystalline (HHC) exposed in Sikkim, India. The metapelites underwent pervasive partial melting through hydrous as well as dehydration melting reactions involving muscovite and biotite to produce a main assemblage of quartz, K-feldspar, plagioclase, biotite, garnet ± sillimanite. Peak metamorphic conditions were 8-9 kbar and ~800 °C. Monazite and zircon crystals in several migmatites collected along a N-S transect show multiple growth domains. The domains were analyzed by microbeam techniques for age (SHRIMP) and trace element composition (LA-ICP-MS) to relate ages to conditions of formation. Monazite preserves the best record of metamorphism with domains that have different zoning pattern, composition and age. Zircon was generally less reactive than monazite, with metamorphic growth zones preserved in only a few samples. The growth of accessory minerals in the presence of melt was episodic in the interval between 31 and 17 Ma, but widespread and diachronous across samples. Systematic variations in the chemical composition of the dated mineral zones (HREE content and negative Eu anomaly) are related to the variation in garnet and K-feldspar abundances, respectively, and thus to metamorphic reactions and P-T stages. In turn, this allows prograde versus decompressional and retrograde melt production to be timed. A hierarchy of timescales characterizes melting which occurred over a period of ~15 Ma (31-17 Ma): a given block within this region traversed the field of melting in 5-7 Ma, whereas individual melting reactions lasted for time durations below, or approaching, the resolution of microbeam dating techniques (~0.6 Ma). An older ~36 Ma high-grade event is recorded in an allocthonous relict related to mafic lenses. We identify two sections of the HHC in Sikkim that traversed similar P-T conditions at different times, separated by a tectonic discontinuity. The higher structural levels reached melting and peak conditions later (~26-23 Ma) than the lower structural levels (~31-27 Ma). Diachronicity across the HHC cannot be reconciled with channel flow models in their simplest form, as it requires two similar high-grade sections to move independently during collision. © 2012 Springer-Verlag.

Heymann F.,University of Kentucky | Heymann F.,European Southern Observatory | Heymann F.,Ruhr University Bochum | Siebenmorgen R.,European Southern Observatory
Astrophysical Journal | Year: 2012

A three-dimensional parallel Monte Carlo (MC) dust radiative transfer code is presented. To overcome the huge computing-time requirements of MC treatments, the computational power of vectorized hardware is used, utilizing either multi-core computer power or graphics processing units. The approach is a self-consistent way to solve the radiative transfer equation in arbitrary dust configurations. The code calculates the equilibrium temperatures of two populations of large grains and stochastic heated polycyclic aromatic hydrocarbons. Anisotropic scattering is treated applying the Heney-Greenstein phase function. The spectral energy distribution (SED) of the object is derived at low spatial resolution by a photon counting procedure and at high spatial resolution by a vectorized ray tracer. The latter allows computation of high signal-to-noise images of the objects at any frequencies and arbitrary viewing angles. We test the robustness of our approach against other radiative transfer codes. The SED and dust temperatures of one- and two-dimensional benchmarks are reproduced at high precision. The parallelization capability of various MC algorithms is analyzed and included in our treatment. We utilize the Lucy algorithm for the optical thin case where the Poisson noise is high, the iteration-free Bjorkman & Wood method to reduce the calculation time, and the Fleck & Canfield diffusion approximation for extreme optical thick cells. The code is applied to model the appearance of active galactic nuclei (AGNs) at optical and infrared wavelengths. The AGN torus is clumpy and includes fluffy composite grains of various sizes made up of silicates and carbon. The dependence of the SED on the number of clumps in the torus and the viewing angle is studied. The appearance of the 10 μm silicate features in absorption or emission is discussed. The SED of the radio-loud quasar 3C 249.1 is fit by the AGN model and a cirrus component to account for the far-infrared emission. © 2012. The American Astronomical Society. All rights reserved..

Beresnyak A.,Los Alamos National Laboratory | Beresnyak A.,Ruhr University Bochum
Monthly Notices of the Royal Astronomical Society | Year: 2012

We revisit the issue of the spectral slope of magnetohydrodynamic (MHD) turbulence in the inertial range and argue that the numerics favour a Goldreich-Sridhar -5/3 slope rather than a -3/2 slope. We also perform precision measurements of the anisotropy of MHD turbulence and determine the anisotropy constant C A= 0.34 of Alfvénic turbulence. Together with the previously measured Kolmogorov constant C K= 4.2, or 3.3 for a purely Alfvénic case, it constitutes a full description of the MHD cascade in terms of spectral quantities, which is of high practical value for astrophysics. © 2012 The Authors Monthly Notices of the Royal Astronomical Society © 2012 RAS.

This paper examines local perceptions of two international humanitarian organisations, the International Rescue Committee (IRC) and Malteser International, in the eastern Democratic Republic of the Congo (DRC) (formerly known as Zaire). At times, the self-perception of these organisations differs considerably from the perceptions of local beneficiaries and stakeholders. This study begins by reviewing the current status of research on local perceptions of externally-introduced humanitarian action. It goes on to discuss the local perceptions of the IRC and Malteser International, as well as the origins of these perceptions, and to show that three different narratives are used by local actors to explain their different perceptions. The paper ends with an examination of the factors that help to account for the differences in perceptions and of the implications of this type of research for humanitarian principles and management, as well as for the study of local perceptions. © 2010 The Author(s). Journal compilation © Overseas Development Institute, 2010.

Seibert F.S.,Ruhr University Bochum
Transplantation | Year: 2016

BACKGROUND: Urinary calprotectin has recently been identified as a promising biomarker for the differentiation between prerenal and intrinsic acute kidney injury (AKI) in the nontransplant population. The present study investigates whether calprotectin is able to differentiate between these 2 entities in transplant recipients as well. METHODS: Urinary calprotectin was assessed by enzyme-linked immunosorbent assay in 328 subjects including 125 cases of intrinsic acute allograft failure, 27 prerenal graft failures, 118 patients with stable graft function, and 58 healthy controls. Acute graft failure was defined as AKI stages 1 to 3 (Acute Kidney Injury Network criteria), exclusion criteria were obstructive uropathy, urothelial carcinoma, and metastatic cancer. The clinical differentiation of prerenal and intrinsic graft failure was performed either by biopsy or by a clinical algorithm including response to fluid repletion, history, physical examination, and urine dipstick examination. RESULTS: Reasons for intrinsic graft failure comprised rejection, acute tubular necrosis, urinary tract infection/pyelonephritis, viral nephritis, and interstitial nephritis. Calprotectin concentrations of patients with stable graft function (50.4 ng/mL) were comparable to healthy controls (54.8 ng/mL, P = 0.70) and prerenal graft failure (53.8 ng/mL, P = 0.62). Median urinary calprotectin was 36 times higher in intrinsic AKI (1955 ng/mL) than in prerenal AKI (P < 0.001). Receiver-operating characteristic curve analysis revealed a high accuracy of calprotectin (area under the curve, 0.94) in the differentiation of intrinsic versus prerenal AKI. A cutoff level of 134.5 ng/mL provided a sensitivity of 90.4% and a specificity of 74.1%. Immunohistochemical stainings for calprotectin in renal allograft biopsy specimens confirmed the serological results. CONCLUSIONS: Urinary calprotectin is a promising biomarker for the differentiation of prerenal and intrinsic acute renal allograft failure. Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.

Hellwig K.,Ruhr University Bochum | Correale J.,Institute For Neurological Research Dr Raul Carrea
Clinical Immunology | Year: 2013

Fertility does not seem to be impaired to a larger extent in women with MS. However, infertility and MS might just come coincidentally together and, therefore, MS patients might undergo assisted reproductive treatment (ART). Thus, during the last years different studies evaluating the effects of ART on MS relapses have been published. All of them reported an increase in annualized relapse rate after ART. Furthermore, in a recent study clinical worsening was associated with an increase in MRI activity. Putative mechanisms involved in MS worsening after ART include: temporary interruption of disease modified therapies, stressful events associated with infertility, and immunological changes induced by hormones such as increase in pro-inflammatory cytokines and anti-MOG antibodies, as well as an increase in immune cell migration across the blood-brain-barrier. Overall, neurologists should be aware of this risk and discuss the pros and cons of the procedures with MS patients. © 2013 Elsevier Inc.

Hoang T.,University of Wisconsin - Madison | Lazarian A.,University of Wisconsin - Madison | Schlickeiser R.,Ruhr University Bochum
Astrophysical Journal | Year: 2012

We study the acceleration of charged grains by magnetohydrodynamic (MHD) turbulence in the interstellar medium (ISM). We begin with revisiting gyroresonance acceleration by taking into account the fluctuations of grain guiding center along a uniform magnetic field (i.e., nonlinear theory - NLT). We calculate grain velocities due to gyroresonance by fast MHD modes using the NLT for different phases of the ISM and compare them with results obtained using quasi-linear theory (QLT). We find for the parameters applicable to the typical ISM phases that the fluctuations of the grain guiding center reduce grain velocities by less than 15%, but they can be important for more special circumstances. We confirm that large grains can be accelerated to super-Alfvénic velocities through gyroresonance. For such super-Alfvénic grains, we investigate the effect of further acceleration via transit-time damping (TTD) by fast modes. We find that due to the broadening of the resonance condition in the NLT, the TTD acceleration is not only important for the cosines of grain pitch angle relative to the magnetic field μ > V A/v, but also for μ < V A/v where v is the grain velocity and V A is the Alfvén speed. We show that the TTD acceleration is dominant over the gyroresonance for large grains, and can increase substantially grain velocities induced by gyroresonance acceleration. We quantify another stochastic acceleration mechanism arising from low-frequency Alfvén waves. We discuss the range of applicability of the mechanisms and their implications. © 2012. The American Astronomical Society. All rights reserved.

Rano I.,Ruhr University Bochum
Bioinspiration and Biomimetics | Year: 2012

Braitenberg vehicles have been used experimentally for decades in robotics with limited empirical understanding. This paper presents the first mathematical model of the vehicle 2b, displaying so-called aggression behaviour, and analyses the possible trajectories for point-like smooth stimulus sources. This sensory-motor steering control mechanism is used to implement biologically grounded target approach, target-seeking or obstacle-avoidance behaviour. However, the analysis of the resulting model reveals that complex and unexpected trajectories can result even for point-like stimuli. We also prove how the implementation of the controller and the vehicle morphology interact to affect the behaviour of the vehicle. This work provides a better understanding of Braitenberg vehicle 2b, explains experimental results and paves the way for a formally grounded application on robotics as well as for a new way of understanding target seeking in biology. © 2012 IOP Publishing Ltd.

Nowrousian M.,Ruhr University Bochum
BMC Research Notes | Year: 2013

Background: RNA-seq studies in metazoa have revealed a distinct, double-peaked (bimodal) distribution of gene expression independent of species and cell type. However, two studies in filamentous fungi yielded conflicting results, with a bimodal distribution in Pyronema confluens and varying distributions in Sordaria macrospora. To obtain a broader overview of global gene expression distributions in fungi, an additional 60 publicly available RNA-seq data sets from six ascomycetes and one basidiomycete were analyzed with respect to gene expression distributions. Results: Clustering of normalized, log§ssub§2§esub§-transformed gene expression levels for each RNA-seq data set yielded distributions with one to five peaks. When only major peaks comprising at least 15% of all analyzed genes were considered, distributions ranged from one to three major peaks, suggesting that fungal gene expression is not generally bimodal. The number of peaks was not correlated with the phylogenetic position of a species; however, higher filamentous asco- and basidiomycetes showed up to three major peaks, whereas gene expression levels in the yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe had only one to two major peaks, with one predominant peak containing at least 70% of all expressed genes. In several species, the number of peaks varied even within a single species, e.g. depending on the growth conditions as evidenced in the one to three major peaks in different samples from Neurospora crassa. Earlier studies based on microarray and SAGE data revealed distributions of gene expression level that followed Zipf's law, i.e. log-transformed gene expression levels were inversely proportional to the log-transformed expression rank of a gene. However, analyses of the fungal RNA-seq data sets could not identify any that confirmed to Zipf's law. Conclusions: Fungal gene expression patterns cannot generally be described by a single type of distribution (bimodal or Zipf's law). One hypothesis to explain this finding might be that gene expression in fungi is highly dynamic, and fine-tuned at the level of transcription not only for individual genes, but also at a global level. © 2013 Nowrousian; licensee BioMed Central Ltd.

Stucker M.,Ruhr University Bochum
Phlebology / Venous Forum of the Royal Society of Medicine | Year: 2013

Compression therapy is considered to be the most important conservative treatment of venous leg ulcers. Until a few years ago, compression bandages were regarded as first-line therapy of venous leg ulcers. However, to date medical compression stockings are the first choice of treatment. With respect to compression therapy of venous leg ulcers the following statements are widely accepted: 1. Compression improves the healing of ulcers when compared with no compression; 2. Multicomponent compression systems are more effective than single-component compression systems; 3. High compression is more effective than lower compression; 4. Medical compression stockings are more effective than compression with short stretch bandages. Healed venous leg ulcers show a high relapse rate without ongoing treatment. The use of medical stockings significantly reduces the amount of recurrent ulcers. Furthermore, the relapse rate of venous leg ulcers can be significantly reduced by a combination of compression therapy and surgery of varicose veins compared with compression therapy alone.

Fares A.,Ruhr University Bochum
Journal of Postgraduate Medicine | Year: 2013

Objectives: This study reviewed previous studies to explore the global patterns of seasonal variation in gastrointestinal diseases. Study Design and Methods: A series of systematic literature reviews were undertaken to identify studies reporting seasonal and monthly data on clinical onset or relapse of gastrointestinal diseases (Acute pancreatitis, inflammatory bowel disease, Peptic ulcer diseases (PUD), gastroesophageal reflux disease, colon cancer and colonic diverticulitis). Thirty-two primary studies (published 1970-2012) from 17 countries were identified. Results: Upon review of the evidence, it appears that the seasonal peaks of PUD are most prominent in colder months while the peak of incidence rate of Crohn diseases in most of the countries subjects were found during the spring and summer seasons. Seasonal trend in the onset of acute pancreatitis exhibits a summer peak in some countries. There were no clearly seasonal peaks noted for the ulcerative colitis. Conclusions: Future experimental and observational studies should consider how the environmental factors (infection, cold, air pollution etc.) or other triggers (dietary habit, alcohol consumption) promotes or hinders such diseases.

Stein R.J.,University of Nebraska - Lincoln | Stein R.J.,Ruhr University Bochum | Waters B.M.,University of Nebraska - Lincoln
Journal of Experimental Botany | Year: 2012

Iron (Fe) is an essential mineral micronutrient for plants and animals. Plants respond to Fe deficiency by increasing root uptake capacity. Identification of gene networks for Fe uptake and homeostasis could result in improved crop growth and nutritional value. Previous studies have used microarrays to identify a large number of genes regulated by Fe deficiency in roots of three Arabidopsis ecotypes. However, a large proportion of these genes may be involved in secondary or genotype-influenced responses rather than in a universal role in Fe uptake or homeostasis. Here we show that a small percentage of the Fe deficiency transcriptome of two contrasting ecotypes, Kas-1 and Tsu-1, was shared with other ecotypes. Kas-1 and Tsu-1 had different timing and magnitude of ferric reductase activity upon Fe withdrawal, and different categories of overrepresented Fe-regulated genes. To gain insights into universal responses of Arabidopsis to Fe deficiency, the Kas-1 and Tsu-1 transcriptomes were compared with those of Col-0, Ler, and C24. In early Fe deficiency (24-48 h), no Fe-downregulated genes and only 10 upregulated genes were found in all ecotypes, and only 20 Fe-downregulated and 58 upregulated genes were found in at least three of the five ecotypes. Supernode gene networks were constructed to visualize conserved Fe homeostasis responses. Contrasting gene expression highlighted different responses to Fe deficiency between ecotypes. This study demonstrates the use of natural variation to identify central Fe-deficiency-regulated genes in plants, and identified genes with potential new roles in signalling during Fe deficiency. © 2011 The Author.

Electrochemical impedance spectroscopy (EIS) is one of the oldest electroanalytical techniques. With respect to the investigation of the electrode-electrolyte interfaces, it has gained wide popularity as a non-destructive, sensitive and highly informative method. A particularly attractive advantage is that it provides a unique opportunity to distinguish contributions from different processes which take place simultaneously at the electrode surface. During the past decade, considerable progress has been made in the field of impedance spectroscopy to advance data acquisition, modelling and spectra analysis. EIS has evolved from slow data acquisition procedures with semi-quantitative interpretation to innovative methodologies which allow simple operation and accurate analysis using hundreds or even thousands of spectra; these spectra can often be recorded as a result of a single experiment. Impedance spectroscopy is nowadays widely combined with other techniques, with successful application in areas ranging from analytical and physical chemistry to localized impedance microscopies. The focus of this review is on recent experimental and theoretical achievements in the characterisation of the interfaces between metal electrodes and aqueous electrolytes using EIS. Some key challenges to further increase the informative power of electrochemical impedance spectroscopy are also outlined. This journal is © The Royal Society of Chemistry.

Wingenfeld K.,University of Hamburg | Wolf O.T.,Ruhr University Bochum
CNS Neuroscience and Therapeutics | Year: 2011

Dysfunctions in hypothalamic-pituitary-adrenal (HPA) axis have been reported for several mental disorders that are also often characterized by memory disturbances. It is now well established that glucocorticoids influence cognitive processes by enhancing memory consolidation and impairing memory retrieval. There is further evidence for an association between HPA axis related disturbances and memory function in mental disorders. The present selective review provides a brief overview of HPA axis dysfunction and its impact on memory function in major depressive disorder, posttraumatic stress disorder, and borderline personality disorder. Furthermore, the relevance of these findings for therapeutic intervention is discussed. © 2010 Blackwell Publishing Ltd.

Steuber T.,The Petroleum Institute | Steuber T.,Nederlandse Aardolie Maatschappij | Schluter M.,Ruhr University Bochum
Earth-Science Reviews | Year: 2012

Numerical ages derived from strontium-isotope stratigraphy of 81 Late Turonian-Maastrichtian rudist localities from the Caribbean to Oman are used to establish stratigraphical ranges of readily identifiable taxa of rudist bivalves (Hippuritida). Based on these ranges, seven biozones for the Turonian-Maastrichtian of the central-eastern Mediterranean Tethys, and three biozones for the mid-Campanian-Maastrichtian of the Arabian Plate are established. Most of these are interval zones, each based on the first stratigraphical appearance of the nominal taxon. Micro-evolutionary patterns such as phyletic size increase have been demonstrated for some of the nominal species, as well as a trend of stratigraphical range expansion from the Turonian to the Maastrichtian. Implications of the geochronology of Late Cretaceous carbonate platforms for the biostratigraphy of other benthic fossils are briefly discussed.Three significant gaps in the stratigraphical distribution of rudist localities in the lower, middle, and uppermost Campanian, respectively, correlate with other records of sea-level change, indicating that they correspond to major eustatic sea-level falls. Only a limited number of rudist taxa is evaluated here, but the early and latest Campanian sea-level falls correspond to faunal turnover and extinction of characteristic associations of Late Cretaceous Hippuritida.The final extinction of the Hippuritida at the Cretaceous/Paleogene boundary is evaluated based on the available numerical ages of eighteen Late Maastrichtian localities. Eighteen genera are recorded at the six youngest localities, which thus have a species richness similar to older Late Cretaceous localities. While the ultimate cause for extinction of the Hippuritida must be evaluated on time scales beyond the resolution of strontium-isotope stratigraphy, the data set evaluated provides some insight into the pattern of their demise, which is considered to be the result of a high degree of endemism indicating limited exchange between increasingly isolated populations. This isolation was possibly related to the gradual decrease in the areal extent of Maastrichtian carbonate platforms due to a long-term cooling trend and local tectonics that affected carbonate platform growth in the regions studied. © 2012 Elsevier B.V.

Devi A.,Ruhr University Bochum
Coordination Chemistry Reviews | Year: 2013

The concept of the transformation of molecules to materials has been well established in the field of chemical vapor deposition (CVD) and atomic layer deposition (ALD). However, materials scientists are always on the lookout for new materials with enhanced functionalities for eventual application in devices. New materials have become an integral part of modern day technology especially in the field of microelectronics and optoelectronics. The importance of CVD and ALD processes for high throughput and coating on complex device geometries is well recognized for these applications. Since the underlying precursor chemistry is one of the main parameters that dictate these processes, there is still scope for further exploratory research, in terms of precursor design and development that suits the demands of advanced technologies. A wide range of precursors can be used to realize specific class of materials but the trend recently has been driven by the reduced thermal budget needed especially for components employed in microelectronics and optoelectronics. The chronological developments in precursors for CVD/ALD point out that, designer precursors are set to play a major role in the field of materials engineering. The desirable growth conditions could be achieved with a proper selection of compounds which may stem from the available class of metal complexes or even engineered compounds. In this review article, the concept of utilizing 'old chemistries' for new CVD and ALD applications will be highlighted focussing on some representative functional materials namely group IV and rare earth oxides. Some of the very recent results on precursor development carried out in the Inorganic Materials Chemistry research group at Bochum, Germany are summarized. © 2013.

Kiedrowski G.V.,Ruhr University Bochum | Otto S.,University of Groningen | Herdewijn P.,Catholic University of Leuven
Journal of Systems Chemistry | Year: 2013

It is our utmost pleasure to launch the Journal of Systems Chemistry. What systems chemistry exactly is will be known in a few years from now when one is able to sketch the scope and vision of the field also based on upcoming contributions to our journal. How systems chemistry came up is more easy to tell. In this editorial we therefore focus predominantly on how the term "Systems Chemistry" came into being and how its scope evolved over recent years. It is perhaps not surprising that the term emerged within the communities researching the origin and synthesis of life, as this is probably the most challenging question in Systems Chemistry. The field however encompasses much more than just this subject - it offers a plethora of new opportunities for the discovery of lifelike dynamic signatures in all areas in chemistry © 2010 von Kiedrowski et al.

Schlickeiser R.,Ruhr University Bochum
Physics of Plasmas | Year: 2015

Since the development of satellite space technology about 50 years ago the solar heliosphere is explored almost routinely by several spacecrafts carrying detectors for measuring the properties of the interplanetary medium including energetic charged particles (cosmic rays), solar wind particle densities, and electromagnetic fields. In 2012, the Voyager 1 spacecraft has even left what could be described as the heliospheric modulation region, as indicated by the sudden disappearance of low energy heliospheric cosmic ray particles. With the available in-situ measurements of interplanetary turbulent electromagnetic fields and of the momentum spectra of different cosmic ray species in different interplanetary environments, the heliosphere is the best cosmic laboratory to test our understanding of the transport and acceleration of cosmic rays in space plasmas. I review both the historical development and the current state of various cosmic ray transport equations. Similarities and differences to transport theories for terrestrial fusion plasmas are highlighted. Any progress in cosmic ray transport requires a detailed understanding of the electromagnetic turbulence that is responsible for the scattering and acceleration of these particles. © 2015 AIP Publishing LLC.

Zittermann A.,Ruhr University Bochum
Molecular Nutrition and Food Research | Year: 2010

This article gives an overview of the vitamin D status in Germany, provides evidence for an independent association of vitamin D deficiency with various chronic diseases, and discusses preventive measures for improving vitamin D status in Germany. The prevalence of vitamin D insufficiency is 40-45% in the general German population. An additional 15-30% are vitamin D deficient. Vitamin D can prevent falls and osteoporotic fractures in older people. There is also accumulating evidence that vitamin D may prevent excess mortality and may probably prevent some chronic diseases that occur in early life such as type 1 diabetes and multiple sclerosis. Adherence to present sun safety policy (avoidance of the sun between 11 amand 3 pm) and dietary recommendations (5-10 μg daily for adults) would, however, definitively lead to vitamin D deficiency. The estimated cost saving effect of improving vitamin D status in Germany might be up to 37.5 billion h annually. It should be the goal of nutrition and medical societies to erase vitamin D deficiency in Germany within the next 5-10 years. To achieve this goal, the daily production of at least 25 μg of vitamin D in the skin or an equivalent oral intake should be guaranteed. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Diakonov D.,RAS Petersburg Nuclear Physics Institute | Tumanov A.G.,St Petersburg Academic University | Vladimirov A.A.,Ruhr University Bochum
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2011

We attempt to build systematically the low-energy effective Lagrangian for the Einstein-Cartan formulation of gravity theory that generally includes the torsion field. We list all invariant action terms in certain given order; some of the invariants are new. We show that in the leading order, the fermion action with torsion possesses additional U(1) L×U(1) R gauge symmetry, with 4+4 components of the torsion (out of the general 24) playing the role of Abelian gauge bosons. The bosonic action quadratic in torsion gives masses to those gauge bosons. Integrating out torsion one obtains a pointlike 4-fermion action of a general form containing vector-vector, axial-vector, and axial-axial interactions. We present a quantum field-theoretic method to average the 4-fermion interaction over the fermion medium, and perform the explicit averaging for free fermions with given chemical potential and temperature. The result is different from that following from the "spin fluid" approach used previously. On the whole, we arrive to rather pessimistic conclusions on the possibility to observe effects of the torsion-induced 4-fermion interaction, although under certain circumstances it may have cosmological consequences. © 2011 American Physical Society.

Kerasnoudis A.,Ruhr University Bochum
Muscle and Nerve | Year: 2013

Introduction: Chronic inflammatory demyelinating polyneuropathy (CIDP) is the most common acquired immune-mediated inflammatory disorder of the peripheral nervous system. The diagnosis is based mainly on the clinical presentation and electrophysiological detection of demyelination. Methods: Several MRI studies have demonstrated hypertrophy and abnormal enhancement of spinal nerve roots or brachial plexus in CIDP, but there have been only anecdotal reports of similar sonographic findings. Results: This article reports the sonographic findings of a CIDP case and includes a review of the literature and previously reported cases. Conclusions: This case report highlights the importance of sonography in the localization and recognition of focal nerve enlargements in patients with CIDP. This method could be a helpful tool in the diagnosis of conduction block in CIDP, especially in cases where a nerve segment cannot be explored easily with the inching technique. Systematic data are needed to confirm this observation. © 2012 Wiley Periodicals, Inc., a Wiley company.

Bellebaum C.,Heinrich Heine University Dusseldorf | Bellebaum C.,Ruhr University Bochum | Colosio M.,University of Padua
Journal of Cognitive Neuroscience | Year: 2014

Humans can adapt their behavior by learning from the consequences of their own actions or by observing others. Gradual active learning of action-outcome contingencies is accompanied by a shift from feedback- to response-based performance monitoring. This shift is reflected by complementary learning-related changes of two ACC-driven ERP components, the feedbackrelated negativity (FRN) and the error-related negativity (ERN), which have both been suggested to signal events "worse than expected," that is, a negative prediction error. Although recent research has identified comparable components for observed behavior and outcomes (observational ERN and FRN), it is as yet unknown, whether these components are similarly modulated by prediction errors and thus also reflect behavioral adaptation. In this study, two groups of 15 participants learned action-outcome contingencies either actively or by observation. In active learners, FRN amplitude for negative feedback decreased and ERN amplitude in response to erroneous actions increased with learning, whereas observational ERN and FRNin observational learners did not exhibit learning-related changes. Learning performance, assessed in test trials without feedback, was comparable between groups, as was the ERN following actively performed errors during test trials. In summary, the results show that action-outcome associations can be learned similarly well actively and by observation. The mechanisms involved appear to differ, with the FRN in active learning reflecting the integration of information about own actions and the accompanying outcomes. © 2014 Massachusetts Institute of Technology.