16 research outputs found

    An efficient shortest path routing algorithm in the data centre network DPillar.

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    DPillar has recently been proposed as a server-centric data centre network and is combinatorially related to the well-known wrapped butterfly network. We explain the relationship between DPillar and the wrapped butterfly network before proving a symmetry property of DPillar. We use this symmetry property to establish a single-path routing algorithm for DPillar that computes a shortest path and has time complexity O(klog(n))O(klog⁥(n)), where k parameterizes the dimension of DPillar and n the number of ports in its switches. Moreover, our algorithm is trivial to implement, being essentially a conditional clause of numeric tests, and improves significantly upon a routing algorithm earlier employed for DPillar. A secondary and important effect of our work is that it emphasises that data centre networks are amenable to a closer combinatorial scrutiny that can significantly improve their computational efficiency and performance

    Direct Identification of the Meloidogyne incognita Secretome Reveals Proteins with Host Cell Reprogramming Potential

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    The root knot nematode, Meloidogyne incognita, is an obligate parasite that causes significant damage to a broad range of host plants. Infection is associated with secretion of proteins surrounded by proliferating cells. Many parasites are known to secrete effectors that interfere with plant innate immunity, enabling infection to occur; they can also release pathogen-associated molecular patterns (PAMPs, e.g., flagellin) that trigger basal immunity through the nematode stylet into the plant cell. This leads to suppression of innate immunity and reprogramming of plant cells to form a feeding structure containing multinucleate giant cells. Effectors have generally been discovered using genetics or bioinformatics, but M. incognita is non-sexual and its genome sequence has not yet been reported. To partially overcome these limitations, we have used mass spectrometry to directly identify 486 proteins secreted by M. incognita. These proteins contain at least segmental sequence identity to those found in our 3 reference databases (published nematode proteins; unpublished M. incognita ESTs; published plant proteins). Several secreted proteins are homologous to plant proteins, which they may mimic, and they contain domains that suggest known effector functions (e.g., regulating the plant cell cycle or growth). Others have regulatory domains that could reprogram cells. Using in situ hybridization we observed that most secreted proteins were produced by the subventral glands, but we found that phasmids also secreted proteins. We annotated the functions of the secreted proteins and classified them according to roles they may play in the development of root knot disease. Our results show that parasite secretomes can be partially characterized without cognate genomic DNA sequence. We observed that the M. incognita secretome overlaps the reported secretome of mammalian parasitic nematodes (e.g., Brugia malayi), suggesting a common parasitic behavior and a possible conservation of function between metazoan parasites of plants and animals

    INDUCED PLURIPOTENT STEM CELLS FOR BASIC AND TRANSLATIONAL RESEARCH ON HD

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    The expression of mutant HTT leads to many cellular alterations, including abnormal vesicle recycling, loss of signalling by brain-derived neurotrophic factor, excitotoxicity, perturbation of Ca2+ signalling, decreases in intracellular ATP, alterations of gene transcription, inhibition of protein clearance pathways, mitochondrial and metabolic disturbances, and ultimately cell death. While robust mammalian systems have been developed to model disease and extensive mechanistic insights have emerged, significant differences between rodent and human cells and between non-neuronal cells and neurons limit the utility of these models for accurately representing human disease. Human pluripotent stem cells can generate highly specified cell populations, including DARPP32-positive MSNs of the striatum, and provide a method for modelling HD in human neurons carrying the mutation. As it is caused by one single gene, HD is an ideal disorder for exploring the utility of modelling disease in induced pluripotent stem cells (iPSCs) through reprogramming adult cells from HD patients with known patterns of disease onset and duration

    Pulmonary surfactant protein A, B, and C mRNA and protein expression in the nitrofen-induced congenital diaphragmatic hernia rat model

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    Pulmonary surfactant protein A, B, and C mRNA and protein expression in the nitrofen-induced congenital diaphragmatic hernia rat model. Van Tuyl M, Blommaart PE, Keijzer R, Wert SE, Ruijter JM, Lamers WH, Tibboel D. Department of Surgery, Sophia Children's Hospital, Erasmus Medical Center Rotterdam, 3015 GJ Rotterdam, The Netherlands. Neonates with congenital diaphragmatic hernia (CDH) suffer from a diaphragmatic defect, lung hypoplasia, and pulmonary hypertension, with poor lung function forming the major clinical challenge. Despite prenatal diagnosis and advanced postnatal treatment strategies, the mortality rate of CDH is still high. CDH has been subject of extensive research over the past decades, but its etiology remains unknown. A major problem with CDH is the failure to predict the individual response to treatment modalities like high-frequency ventilation, inhaled nitric oxide, and extracorporeal membrane oxygenation. In this study, we tested the possibility that CDH lungs are surfactant protein deficient, which could explain the respiratory failure and difficulties in treating CDH infants. We investigated this hypothesis in the nitrofen-induced CDH rat model and assessed the cellular concentrations of surfactant protein (SP)-A, -B, and -C mRNA with a quantitative radioactive in situ hybridization technique. No differences were observed between control and CDH lungs for SP mRNA expression patterns. The cellular concentration (mean OD) of SP-A and SP-B mRNA was similar at all stages whereas the mean OD of SP-C mRNA and the volume fraction of cells (% Area) expressing SP mRNA was higher in CDH lungs at term. Immunohistochemical analysis revealed no differences between control and CDH lungs for SP protein expression. No differences in the mean OD or % Area for the SP mRNAs were found between the ipsi- and contralateral side of CDH lungs. We conclude that there is no primary deficiency of surfactant proteins in the nitrofen-induced CDH rat mode

    Intra-Datacenter Network Architectures

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    This Handbook chapter provides an overview of existing interconnection topologies and architectures for large-scale cloud computing systems. We discuss (a) tree-based solutions (also referred to as indirect topologies in this chapter), largely adopted in most of today’s data center systems, as well as (b) directly connected topologies, such as full mesh (all-to-all), fattened butterfy, and HyperX. This chapter also touches upon some emerging interconnect solutions enabled by recent advances in photonic integrated technologies and switches, while more details about these aspects can be found in the Handbook Chaps. 21, 24, and 25
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