21 research outputs found
Parallel Sort-Based Matching for Data Distribution Management on Shared-Memory Multiprocessors
In this paper we consider the problem of identifying intersections between
two sets of d-dimensional axis-parallel rectangles. This is a common problem
that arises in many agent-based simulation studies, and is of central
importance in the context of High Level Architecture (HLA), where it is at the
core of the Data Distribution Management (DDM) service. Several realizations of
the DDM service have been proposed; however, many of them are either
inefficient or inherently sequential. These are serious limitations since
multicore processors are now ubiquitous, and DDM algorithms -- being
CPU-intensive -- could benefit from additional computing power. We propose a
parallel version of the Sort-Based Matching algorithm for shared-memory
multiprocessors. Sort-Based Matching is one of the most efficient serial
algorithms for the DDM problem, but is quite difficult to parallelize due to
data dependencies. We describe the algorithm and compute its asymptotic running
time; we complete the analysis by assessing its performance and scalability
through extensive experiments on two commodity multicore systems based on a
dual socket Intel Xeon processor, and a single socket Intel Core i7 processor.Comment: Proceedings of the 21-th ACM/IEEE International Symposium on
Distributed Simulation and Real Time Applications (DS-RT 2017). Best Paper
Award @DS-RT 201
Distributed Hybrid Simulation of the Internet of Things and Smart Territories
This paper deals with the use of hybrid simulation to build and compose
heterogeneous simulation scenarios that can be proficiently exploited to model
and represent the Internet of Things (IoT). Hybrid simulation is a methodology
that combines multiple modalities of modeling/simulation. Complex scenarios are
decomposed into simpler ones, each one being simulated through a specific
simulation strategy. All these simulation building blocks are then synchronized
and coordinated. This simulation methodology is an ideal one to represent IoT
setups, which are usually very demanding, due to the heterogeneity of possible
scenarios arising from the massive deployment of an enormous amount of sensors
and devices. We present a use case concerned with the distributed simulation of
smart territories, a novel view of decentralized geographical spaces that,
thanks to the use of IoT, builds ICT services to manage resources in a way that
is sustainable and not harmful to the environment. Three different simulation
models are combined together, namely, an adaptive agent-based parallel and
distributed simulator, an OMNeT++ based discrete event simulator and a
script-language simulator based on MATLAB. Results from a performance analysis
confirm the viability of using hybrid simulation to model complex IoT
scenarios.Comment: arXiv admin note: substantial text overlap with arXiv:1605.0487
Diagnosis and Treatment of Parkinson's Disease
Parkinson's disease is diagnosed by history and physical examination and there are no laboratory investigations available to aid the diagnosis of Parkinson's disease. Confirmation of diagnosis of Parkinson's disease thus remains a difficulty. This book brings forth an update of most recent developments made in terms of biomarkers and various imaging techniques with potential use for diagnosing Parkinson's disease. A detailed discussion about the differential diagnosis of Parkinson's disease also follows as Parkinson's disease may be difficult to differentiate from other mimicking conditions at times. As Parkinson's disease affects many systems of human body, a multimodality treatment of this condition is necessary to improve the quality of life of patients. This book provides detailed information on the currently available variety of treatments for Parkinson's disease including pharmacotherapy, physical therapy and surgical treatments of Parkinson's disease. Postoperative care of patients of Parkinson's disease has also been discussed in an organized manner in this text. Clinicians dealing with day to day problems caused by Parkinson's disease as well as other healthcare workers can use beneficial treatment outlines provided in this book
Proceedings of the ECCOMAS Thematic Conference on Multibody Dynamics 2015
This volume contains the full papers accepted for presentation at the ECCOMAS Thematic Conference on Multibody Dynamics 2015 held in the Barcelona School of Industrial Engineering, Universitat Politècnica de Catalunya, on June 29 - July 2, 2015. The ECCOMAS Thematic Conference on Multibody Dynamics is an international meeting held once every two years in a European country. Continuing the very successful series of past conferences that have been organized in Lisbon (2003), Madrid (2005), Milan (2007), Warsaw (2009), Brussels (2011) and Zagreb (2013); this edition will once again serve as a meeting point for the international researchers, scientists and experts from academia, research laboratories and industry working in the area of multibody dynamics. Applications are related to many fields of contemporary engineering, such as vehicle and railway systems, aeronautical and space vehicles, robotic manipulators, mechatronic and autonomous systems, smart structures, biomechanical systems and nanotechnologies. The topics of the conference include, but are not restricted to: ● Formulations and Numerical Methods ● Efficient Methods and Real-Time Applications ● Flexible Multibody Dynamics ● Contact Dynamics and Constraints ● Multiphysics and Coupled Problems ● Control and Optimization ● Software Development and Computer Technology ● Aerospace and Maritime Applications ● Biomechanics ● Railroad Vehicle Dynamics ● Road Vehicle Dynamics ● Robotics ● Benchmark ProblemsPostprint (published version
Recent Advances in Antibody Therapeutics
Since first receiving approval in 1986, antibody-based therapeutics have been the most successful modality for the treatment of various diseases. This Special Issue of IJMS, “Recent Advances in Antibody Therapeutics”, presents leading-edge articles and reviews for discovery, development, and clinical applications of therapeutic antibodies, covering antibody drug conjugates (ADCs), GPCR-targeting antibodies, a functional antibody screening, bioassay of bispecific antibodies, antibody applications for cardiovascular diseases, antibody delivery to CNS, etc. The excellent studies in this Special Issue would valuable insight for scientists and clinicians in the field of therapeutic antibodie
La spectrométrie de masse : un couteau suisse pour disséquer la structure et la fonction du spermatoprotéasome
Le protéasome est le complexe enzymatique protéolytique principal de la cellule. Son cœur catalytique (20S) est formé de quatre anneaux heptamériques. Son activité et sa spécificité de substrat peuvent être régulées par les complexes 19S, PA28alphaß, PA28gamma et PA200 ainsi que par des sous-unités 20S alternatives. La spermatogenèse est un processus de différenciation des cellules germinales mâles: les spermatogonies (SPG) se transforment en spermatocytes (SPC), en spermatides (SPT) puis en spermatozoïdes. Ce processus requière une protéolyse intense. Le spermatoprotéasome (spt20S) est spécifique des gamètes en développement et essentiel à la spermatogenèse. Il diffère du protéasome standard (std20S) par la sous-unité alpha4s qui remplace la sous-unité constitutive alpha4. Le spt20S joue un rôle important avec PA200 dans la progression de la méiose, mais les mécanismes qui le rendent différent du std20S restent inconnus. Nous avons établi des stratégies protéomiques complémentaires pour caractériser les complexes du protéasome immunopurifiés à partir de testicules. L'analyse Top-Down de protéasome purifié, nous a permis de montrer pour la première fois qu'alpha4s et alpha4 portent les mêmes MPTs. La protéomique Bottom-Up, nous a permis de comparer les immunopurifications (IPs) de protéasomes totaux avec celles obtenues avec un anticorps spécifique du stp20S que nous avons développé. Nous avons établi qu'alpha4 et alpha4s ne coexistent pas dans le même 20S, bien qu'ils soient presque également abondants dans les testicules. Nous avons également trouvé plus de 19S et de PA200 liés au spt20S qu'au std20S. Les autres protéines préférentiellement associées au spt20S incluent PI31 et Fbxo7 qui sont cruciales pour la fertilité et d'importants médiateurs du transport du protéasome et de l'ancrage des E3 ligases - deux processus qui semblent cruciaux pour la fonction du spt20S pendant la spermatogenèse. Nous avons ensuite obtenu des cellules germinales à différents stades de la différenciation et l'analyse protéomique des lysats ainsi que des IPs, nous a permis d'établir un interactome dynamique du protéasome tout au long de la spermatogenèse. Nous avons observé un changement total du std20S au spt20S entre les SPG pré-méiotiques et les SPC/SPT méiotiques et post-méiotiques. Un changement d'expression semble responsable, plutôt qu'une incorporation préférentielle d'alpha4s. En entrant dans la méiose, l'association de PA200 avec le protéasome a augmenté 7 fois, confirmant son importance dans le développement des gamètes. Bien que PA200 soit d'après la littérature le principal activateur du spt20S, nous montrons que le 19S est est en réalité majoritaire, lié à 60% des 20S dans les SPC - une activation du protéasome sans précédent. De nombreux partenaires du spt20S sont identifiés à la fois dans les cellules germinales et dans les testicules entiers, montrant la robustesse de nos méthodes. Ceux-ci incluent des protéines synaptonémales, de nombreuses protéines impliquées dans l'ubiquitylation, le cycle cellulaire et la progression méiotique ainsi que le transport cellulaire, en accord avec les fonctions du spt20S proposées dans la littérature. Le passage d'alpha4 à alpha4s semble crucial pour la méiose, mais quelles sont les bases moléculaires de cette transition ? L'échange hydrogène-deutérium nous a permis de montrer pour la première fois que les deux protéasomes présentent des interfaces d'interaction différentes : alpha4s contient des régions plus flexibles qu'alpha4. Cette découverte est confirmée par des pull-down in vitro montrant que le 19S se lie plus fortement au spt20S qu'au std20S, expliquant la hausse d'activité protéolytique pendant la méiose. L'activité trypsique du spt20S est plus élevée que celle du std20S in vitro, ce qui pourrait refléter la nécessité de dégradation des histones. Globalement, nos données révèlent un processus de régulation du spt20S qui est plus complexe que ce qui avait été suggéré précédemment et jettent les bases des différences structurales et fonctionnelles entre le spt20S et le std20S.The proteasome is the main enzymatic complex for targeted proteolysis in the cell. Its core complex (20S) consists of four stacked heptameric rings and requires activator complexes: 19S, PA28alphaß, PA28gamma and PA200, which regulate 20S activity and substrate specificity. Alternative 20S subunits exist to further modulate the proteasome activity. Spermatogenesis is a process of male germ cell differentiation, where spermatogonia (SPG) transform through spermatocyte (SPC), then spermatid (SPT) stages, to become spermatozoa. This process requires intense proteolysis. The spermatoproteasome (spt20S) is specific to the developing gametes and essential for spermatogenesis. It differs from the standard proteasome (std20S) by only one subunit - alpha4s, which replaces the constitutive alpha4 subunit. Together with PA200, the spt20S plays an important role in meiosis progression, however, the mechanisms that make it different compared to std20S remain unknown. We established complementary proteomic pipelines for characterisation of proteasome complexes in the testes, combining immunopurification (IP) and mass spectrometry (MS) analysis. Our Top-Down analysis of purified proteasome, showed for the first time that both alpha4 and alpha4s carry the same PTMs. Using Bottom-Up proteomics we compared the interactome of total proteasomes with that of the spt20S only, obtained using a specific antibody we developed for this purpose. We established that alpha4 and alpha4s do not co-exist in the same 20S, although they are almost equally abundant in the testes. We also measured that 19S and PA200 regulators were bound in higher ratios to the spt20S compared to std20S. Among other preferentially-associated proteins of spt20S were PI31 and Fbxo7, both shown to be crucial for fertility. They mediate proteasome transport and docking of E3 ligases - both processes that could be crucial for spt20S function. We then obtained germ cells at different differentiation stages and performed a proteomics analysis of both lysates and IP-ed proteasome complexes, to establish a dynamic image of the proteasome throughout spermatogenesis. We observed a complete shift from std20S to spt20S between pre-meiotic SPG and meiotic and post-meiotic SPC and SPT cells. We explained this by a shift in expression, rather than preferential incorporation of alpha4s. Upon entering meiosis, the PA200 association with core proteasome increased 7-fold, marking its importance in gamete development. Although PA200 was represented in literature as the main spt20S interactor, we show that 19S was undoubtedly stoichiometrically dominant, occupying 60% of the existing 20S in SPCs - an unprecedented proteasome activation. Identified spt20S-interacting proteins largely correlated with previous interactome analysis on the whole testes, showing robustness of our methods. We identified synaptonemal proteins bound exclusively to spt20S and numerous proteins involved in ubiquitylation, cell cycle and meiotic progression as well as cellular transport, which fits the current model of spt20S role, proposed by earlier work. The shift from alpha4 to alpha4s in meiosis was shown to be crucial, but what is the molecular basis for this transition? The hydrogen-deuterium exchange experiment coupled to MS helped us to show for the first time that the two proteasomes exhibit different binding interfaces: alpha4s contains regions that are more flexible compared to alpha4. We further supported this finding with pull-down assays, which showed that 19S binds more strongly to the spt20S than to std20S, which would explain the increase in proteolytic activity required during meiosis. The spt20S showed a higher tryptic activity compared to the std20S in vitro, which might reflect a particular need for histone degradation. Altogether, our data reveal a more complex process of spt20S regulation than previously suggested and set the basis for structural and functional differences between the spt20S and std20S
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Studies on assembly and genetic variation in mitochondrial respiratory complex I
Complex I (NADH:ubiquinone oxidoreductase) couples electron transfer to proton translocation across the inner mitochondrial membrane, to drive the synthesis of ATP. Its distinctive L-shaped structure comprises 45 subunits, encoded by both the mitochondrial and nuclear genomes, which are assembled by a complicated modular pathway. Complex I genetic defects are the most common cause of mitochondrial disorders and often present in early childhood, with high mortality rates. Recent high-resolution electron cryo-microscopy structures of mammalian complex I provide a foundation for both interpreting biochemical and biomedical data and understanding the catalytic mechanism.
First, this thesis explores how the flavin cofactor is inserted into the NADH-binding (N-) domain of complex I. Genetic manipulation of cultured human cells, to starve them of flavin, revealed a hierarchal impact on the mitochondrial flavoproteome. High riboflavin content in the growth media ameliorated observed phenotypes, requiring cell conditioning in low riboflavin conditions. CRISPR knockout of the putative mitochondrial flavin transporter SLC25A32 demonstrated the severe impact of decreased flavin on complexes I and II, and mass spectrometry ‘complexome’ analyses suggest that the N-domain is still assembled onto complex I in the absence of the flavin.
Second, the model organism Yarrowia lipolytica was used to assess the importance of residues in the quinone-binding site of complex I. Three residues with proposed roles in binding the quinone head-group were targeted. One variant was catalytically inactive, while two retained some activity. They showed decreased ability to reduce physiologically-relevant, long chain quinones, but their ability to reduce short-chain analogues was affected less severely. The results suggest a complicated picture in which interactions between the protein and both the hydrophilic quinone head-group and hydrophobic isoprenoid chain contribute to quinone-binding affinity and catalysis.
Finally, a model for human complex I, generated from a recent high-resolution structure of mouse complex I, was used to investigate whether the pathogenicity of human variants could be predicted. Structural information on variant residues, including their secondary structure, proximity to key features and surface exposure, was collated and the power of each property to predict pathogenicity investigated. The analysis was then extended to the whole structure, to identify potential pathogenic hotspots in the enzyme, inform future studies of functionally important regions in complex I, and aid the diagnosis of clinically relevant pathogenic variants
Immunohistochemical and electrophysiological investigation of E/I balance alterations in animal models of frontotemporal dementia
Behavioural variant frontotemporal dementia (bvFTD) is a neurodegenerative disease characterised by changes in behaviour. Apathy, behavioural disinhibition and stereotyped behaviours are the first symptoms to appear and all have a basis in reward and pleasure deficits. The ventral striatum and ventral regions of the globus pallidus are involved in reward and pleasure. It is therefore reasonable to suggest alterations in these regions may underpin bvFTD. One postulated contributory factor is alteration in E/I balance in striatal regions. GABAergic interneurons play a role in E/I balance, acting as local inhibitory brakes, they are therefore a rational target for research investigating early biological predictors of bvFTD.
To investigate this, we will carry out immunohistochemical staining for GABAergic interneurons (parvalbumin and neuronal nitric oxide synthase) in striatal regions of brains taken from CHMP2B mice, a validated animal model of bvFTD. We hypothesise that there will be fewer GABAergic interneurons in the striatum which may lead to ‘reward-seeking’ behaviour in bvFTD. This will also enable us to investigate any preclinical alterations in interneuron expression within this region. Results will be analysed using a mixed ANOVA and if significant, post hoc t-tests will be used. The second part of our study will involve extracellular recordings from CHMP2B mouse brains using a multi-electrode array (MEA). This will enable us to determine if there are alterations in local field potentials (LFP) in preclinical and symptomatic animals. We will also be able to see if neuromodulators such as serotonin and dopamine effect LFPs after bath application. We will develop slice preparations to preserve pathways between the ventral tegmental area and the ventral pallidum, an output structure of the striatum, and the dorsal raphe nucleus and the VP. Using the MEA we will stimulate an endogenous release of dopamine and serotonin using the slice preparations as described above. This will enable us to see if there are any changes in LFPs after endogenous release of neuromodulators. We hypothesise there will be an increase in LFPs due to loss of GABAergic interneurons