283 research outputs found

    Euclidean Greedy Drawings of Trees

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    Greedy embedding (or drawing) is a simple and efficient strategy to route messages in wireless sensor networks. For each source-destination pair of nodes s, t in a greedy embedding there is always a neighbor u of s that is closer to t according to some distance metric. The existence of greedy embeddings in the Euclidean plane R^2 is known for certain graph classes such as 3-connected planar graphs. We completely characterize the trees that admit a greedy embedding in R^2. This answers a question by Angelini et al. (Graph Drawing 2009) and is a further step in characterizing the graphs that admit Euclidean greedy embeddings.Comment: Expanded version of a paper to appear in the 21st European Symposium on Algorithms (ESA 2013). 24 pages, 20 figure

    Combined use of platelet-rich plasma and adipose tissue-derived mesenchymal stem cells shows a synergistic effect in experimental spinal cord injury

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    Spinal cord injury (SCI) as a crippling disability causes tissue degeneration via neuron loss and fiber disruption. Some researchers have tried to reverse or minimize these changes. Platelet-rich plasma (PRP) is a biological product derived from peripheral blood containing a variety of growth factors. PRP has been extensively used in regenerative medicine. On the other hand, via secreting neuroprotective growth factors, mesenchymal stem cells (MSCs) have shown a promising potential in repairing central nervous system deficits. This study investigated the therapeutic effect of the combined use of MSCs and PRP in a rat model of SCI. We used real time-PCR method for evaluation of Bcl-2, Bax and caspase 3 expressions, TUNEL test for apoptotic cell death assessment, and neurofilament NF200 immunohistochemistry for examination of axonal regeneration. The results showed that co-treatment with MSCs and PRP efficiently alleviated the evaluated categories. Significant differences were observed in expression of Bcl-2 and caspase3, but not Bax, apoptotic index and the number of NF200 positive axons (for all P </= 0.01) between co-treatment animals compared with those treated with only MSCs or PRP. In conclusion, this study showed that combination of MSCs and PRP synergistically promotes their therapeutic effects in the SCI

    An analytic network process model to prioritize supply chain risks in green residential megaprojects

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    Megaprojects and specifically ‘green’ construction of residential megaprojects can contain significant risks of failure. To design proper risk mitigation strategies, after identifying key risk factors, the next step is to conduct assessments that would facilitate the process of risk element prioritization. Risk assessment comprises the establishment of factor interrelation and discerning the indicators of importance. This research proposes a novel version of an integrated prioritization method and analyzes twelve all-inclusive key supply chain oriented risk factors identified in a previous study. Through a comprehensive literature review three criteria, impact, probability, and manageability are selected. Also, a fourth criterion namely influence rate is included in the model, based on the driving powers that can also be derived from the Interpretive Structural Modeling’s (ISM) assessment. Fundamentally, the calculations hinge on the Analytic Network Process (ANP) method which provides an assessment of the alternatives’ weights based on pairwise comparisons concerning the criteria specified. To enhance the accuracy of the perceptive judgments of the expert panelists, a bell-shaped fuzzy function is used to convert the verbal statements to crisp values. In addition, Row Sensitivity Analysis is administered to check the stability of the results and provide predictive scenarios. To validate the model, a case study, located in Iran, was conducted, where an expert panel consisting of four individuals made the pair-wise comparisons through an ANP questionnaire. Results indicate priority and sensitivity of the alternatives concerning criteria, for the case under study

    On the Area Requirements of Planar Greedy Drawings of Triconnected Planar Graphs

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    In this paper we study the area requirements of planar greedy drawings of triconnected planar graphs. Cao, Strelzoff, and Sun exhibited a family H\cal H of subdivisions of triconnected plane graphs and claimed that every planar greedy drawing of the graphs in H\mathcal H respecting the prescribed plane embedding requires exponential area. However, we show that every nn-vertex graph in H\cal H actually has a planar greedy drawing respecting the prescribed plane embedding on an O(n)×O(n)O(n)\times O(n) grid. This reopens the question whether triconnected planar graphs admit planar greedy drawings on a polynomial-size grid. Further, we provide evidence for a positive answer to the above question by proving that every nn-vertex Halin graph admits a planar greedy drawing on an O(n)×O(n)O(n)\times O(n) grid. Both such results are obtained by actually constructing drawings that are convex and angle-monotone. Finally, we consider α\alpha-Schnyder drawings, which are angle-monotone and hence greedy if α30\alpha\leq 30^\circ, and show that there exist planar triangulations for which every α\alpha-Schnyder drawing with a fixed α<60\alpha<60^\circ requires exponential area for any resolution rule

    In vitro assessment of the combined effect of eicosapentaenoic acid, green tea extract and curcumin C3 on protein loss in C2C12 myotubes

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    EPA has been clinically shown to reduce muscle wasting during cancer cachexia. This study investigates whether curcumin or green tea extract (GTE) enhances the ability of low doses of eicosapentaenoic acid (EPA) to reduce loss of muscle protein in an in vitro model. A low dose of EPA with minimal anti-cachectic activity was chosen to evaluate any potential synergistic effect with curcumin or GTE. Depression of protein synthesis and increase in degradation was determined in C2C12 myotubes in response to tumour necrosis factor-α (TNF-α) and proteolysis-inducing factor (PIF). EPA (50 μM) or curcumin (10 μg ml−1) alone had little effect on protein degradation caused by PIF but the combination produced complete inhibition, as did the combination with GTE (10 μg ml−1). In response to TNF-α (25 ng ml−1)-induced protein degradation, EPA had a small, but not significant effect on protein degradation; however, when curcumin and GTE were combined with EPA, the effect was enhanced. EPA completely attenuated the depression of protein synthesis caused by TNF-α, but not that caused by PIF. The combination of EPA with curcumin produced a significant increase in protein synthesis to both agents. GTE alone or in combination with EPA had no effect on the depression of protein synthesis by TNF-α, but did significantly increase protein synthesis in PIF-treated cells. Both TNF-α and PIF significantly reduced myotube diameter from 17 to 13 μm for TNF-α (23.5%) and 15 μm (11.8%) for PIF However the triple combination of EPA, curcumin and GTE returned diameters to values not significantly different from the control. These results suggest that either curcumin or GTE or the combination could enhance the anti-catabolic effect of EPA on lean body mass

    Palladium nanoparticles supported on fluorine-doped tin oxide as an efficient heterogeneous catalyst for Suzuki coupling and 4-nitrophenol reduction

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    Immobilization of palladium nanoparticles onto the fluorine-doped tin oxide (FTO) as support Pd/FTO, resulted in a highly active heterogeneous catalyst for Suzuki-Miyaura cross-coupling reactions and 4-nitrophenol reduction. The Pd/FTO catalyst has been synthesized by immobilization of palladium nanoparticles onto FTO via a simple impregnation method. ICP-MS analysis confirmed that there is 0.11 mmol/g of palladium was loaded successfully on FTO support. The crystallinity, morphologies, compositions and surface properties of Pd/FTO were fully characterized by various techniques. It was further examined for its catalytic activity and robustness in Suzuki coupling reaction with different aryl halides and solvents. The yields obtained from Suzuki coupling reactions were basically over 80%. The prepared catalyst was also tested on mild reaction such as reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). Pd/FTO catalyst exhibited high catalytic activity towards 4-NP reduction with a rate constant of 1.776 min(-1) and turnover frequency (TOF) value of 29.1 hr(-1). The findings revealed that Pd/FTO also maintained its high stability for five consecutive runs in Suzuki reactions and 4-NP reductions. The catalyst showed excellent catalytic activities by using a small amount of Pd/FTO for the Suzuki coupling reaction and 4-NP reduction

    Role of HDAC3 on p53 Expression and Apoptosis in T Cells of Patients with Multiple Sclerosis

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    Background: Histone deacetylase 3 (HDAC3) belongs to a family of proteins which plays an important role in protein acetylation, chromatin remodeling and transcription of genes, including those that are involved in cell proliferation and cell death. While increased expression of HDAC3 is seen in neoplastic cells, the role of HDAC3 in T cells and their role in autoimmune disease is not known. Methodology/Principal Findings: Applying Affymetrix GeneChip Human Gene 1.0 ST Array and the mixed effects model for gene set analysis, we compared gene expression profiles between multiple sclerosis (MS) patients and healthy controls (HC). Within the Apoptosis_GO gene set, the constitutive expression level of HDAC3 in peripheral blood mononuclear cell (PBMC) was significantly increased in MS patients when compared to controls. Following addition of trichostatin A (TSA), an inhibitor of HDAC3, we examined the expression of p53 by flow cytometry and p53 targeted genes by real time RT-PCR in MS and HC. Culture of PBMC with TSA resulted in increased expression of p53 in HC but not in MS patients. TSA treated T cells from MS patients also showed reduced sensitivity to apoptosis when compared to HC, which was independent of activation of p53 targeted pro-apoptotic genes. Conclusion/Significance: MS patients, when compared to controls, show an increased expression of HDAC3 and relative resistance to TSA induced apoptosis in T cells. Increased expression of HDAC3 in PBMC of MS patients may render putativ
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