1,206 research outputs found

    Deadline Constrained Cloud Computing Resources Scheduling through an Ant Colony System Approach

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    Cloud computing resources scheduling is essential for executing workflows in the cloud platform because it relates to both execution time and execution cost. In this paper, we adopt a model that optimizes the execution cost while meeting deadline constraints. In solving this problem, we propose an Improved Ant Colony System (IACS) approach featuring two novel strategies. Firstly, a dynamic heuristic strategy is used to calculate a heuristic value during an evolutionary process by taking the workflow topological structure into consideration. Secondly, a double search strategy is used to initialize the pheromone and calculate the heuristic value according to the execution time at the beginning and to initialize the pheromone and calculate heuristic value according to the execution cost after a feasible solution is found. Therefore, the proposed IACS is adaptive to the search environment and to different objectives. We have conducted extensive experiments based on workflows with different scales and different cloud resources. We compare the result with a particle swarm optimization (PSO) approach and a dynamic objective genetic algorithm (DOGA) approach. Experimental results show that IACS is able to find better solutions with a lower cost than both PSO and DOGA do on various scheduling scales and deadline conditions

    Optimal Real-time Spectrum Sharing between Cooperative Relay and Ad-hoc Networks

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    Optimization based spectrum sharing strategies have been widely studied. However, these strategies usually require a great amount of real-time computation and significant signaling delay, and thus are hard to be fulfilled in practical scenarios. This paper investigates optimal real-time spectrum sharing between a cooperative relay network (CRN) and a nearby ad-hoc network. Specifically, we optimize the spectrum access and resource allocation strategies of the CRN so that the average traffic collision time between the two networks can be minimized while maintaining a required throughput for the CRN. The development is first for a frame-level setting, and then is extended to an ergodic setting. For the latter setting, we propose an appealing optimal real-time spectrum sharing strategy via Lagrangian dual optimization. The proposed method only involves a small amount of real-time computation and negligible control delay, and thus is suitable for practical implementations. Simulation results are presented to demonstrate the efficiency of the proposed strategies.Comment: One typo in the caption of Figure 5 is correcte

    Improving the Magnetic Resonance Imaging Contrast and Detection Methods with Engineered Magnetic Nanoparticles

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    Engineering and functionalizing magnetic nanoparticles have been an area of the extensive research and development in the biomedical and nanomedicine fields. Because their biocompatibility and toxicity are well investigated and better understood, magnetic nanoparticles, especially iron oxide nanoparticles, are better suited materials as contrast agents for magnetic resonance imaging (MRI) and for image-directed delivery of therapeutics. Given tunable magnetic properties and various surface chemistries from the coating materials, most applications of engineered magnetic nanoparticles take advantages of their superb MRI contrast enhancing capability as well as surface functionalities. It has been found that MRI contrast enhancement by magnetic nanoparticles is highly dependent on the composition, size and surface properties as well as the degree of aggregation of the nanoparticles. Therefore, understanding the relationships between these intrinsic parameters and the relaxivities that contribute to MRI contrast can lead to establishing essential guidance that may direct the design of engineered magnetic nanoparticles for theranostics applications. On the other hand, new contrast mechanism and imaging strategy can be developed based on the novel properties of engineered magnetic nanoparticles. This review will focus on discussing the recent findings on some chemical and physical properties of engineered magnetic nanoparticles affecting the relaxivities as well as the impact on MRI contrast. Furthermore, MRI methods for imaging magnetic nanoparticles including several newly developed MRI approaches aiming at improving the detection and quantification of the engineered magnetic nanoparticles are described

    No relationship between the distribution of mast cells and the survival of stage IIIB colon cancer patients

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    <p>Abstract</p> <p>Background</p> <p>Mast cells promote the progression of experimental tumors and might be a valuable therapeutic target. However, the relevant clinical evidence is still controversial. This study analyzed the relationship between the distribution of mast cells and the survival of patients with colon cancer to study whether mast cells contribute to tumor progression.</p> <p>Materials and methods</p> <p>Ninety-three cases of pathologically confirmed primary cancer tissues matched with adjacent normal mucosa, metastases of regional-draining lymph nodes and regional-draining lymph nodes without metastases were collected from stage IIIB colon carcinoma patients between January 1997 and July 2004 at the Cancer Center of Sun Yat-Sen University. Tryptase-positive mast cells were counted. The relationships of the distribution of mast cells with clinicopathologic parameters and 5-year survival were analyzed.</p> <p>Results</p> <p>Although the mast cell count in the mucosa adjacent to the primary colon cancer was significantly higher than that in the stroma of the primary colon cancer, no difference in mast cell counts was observed between the stroma in lymph node metastasis and the lymph tissue adjacent to the metastasis. Additionally, the mast cell count in the regional-draining lymph node without the invasion of cancer cells was significantly higher than that in the stroma of lymph node metastasis and adjacent lymph tissue. However, none of those mast cell counts was related to 5-year survival.</p> <p>Conclusion</p> <p>Although mast cell count varied with location, none of the mast cell counts was related to 5-year survival, suggesting that mast cells do not contribute to the progression of stage IIIB colon cancer.</p

    Tetra­aqua­(nitrato-κ2 O,O′)bis­(pyridinium-4-carboxyl­ate-κO)europium(III) dinitrate

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    The asymmetric unit of the title compound, [Eu(NO3)(C6H5NO2)2(H2O)4](NO3)2, consists of one-half of the C 2 symmetric coordination cation and one nitrate anion. The eight-coordinated EuIII atom is in a distorted dodeca­hedral coordination environment. The coordination cations and nitrate anions are connected via O—H⋯O and N—H⋯O hydrogen bonds into a three-dimensional network

    Effect of β-nerve growth factor on differentiation of endothelial progenitor cells in rats

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    Purpose: To investigate the effect of recombinant adenovirus-mediated human β-nerve growth factor (Ad-EGFP-hβ-NGF) on the differentiation of endothelial progenitor cells (EPCs) in rats.Methods: The successfully constructed Ad-EGFP-hβ-NGF and its negative control Ad-EGFP were infected into the isolated and purified rat EPCs to observe their morphological changes. Enzyme-linked immunosorbent assay (ELISA) was conducted to detect the levels of vascular endothelial growth factor (VEGF), von Willebrand factor (vWF) and basic fibroblast growth factor (bFGF) in different rat EPC culture solutions. Western blot was performed to determine the expression of tyrosine kinase receptor A (TrKA) protein in different groups of EPCs.Results: Primary fibrous EPCs were converted into epithelium-like cells. After infection with Ad-EGFPhβ- NGF for 1 week, some EPCs became round and exhibited neural stem cell-like changes. The expression levels of VEGF, vWF and bFGF in the Ad-EGFP-hβ-NGF infection group were significantly higher than those in the control group (p &lt; 0.01). TrKA protein in Ad-EGFP-hβ-NGF infection was also significantly up-regulated compared with that in the negative control and blank control groups (p &lt;0.01).Conclusion: β-NGF up-regulates the expression of TrKA receptor protein and secretion of angiogenic growth factors (i.e., VEGF, vWF and bFGF), thereby promoting the differentiation of rat EPCs, which may contribute to angiopoiesis or vascular repair.Keywords: β-Nerve growth factor, Endothelial progenitor cells, Angiogenic growth factors, Tyrosine kinase receptor A, Cell differentiatio

    Multi-Modal Automatic Prosody Annotation with Contrastive Pretraining of SSWP

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    In the realm of expressive Text-to-Speech (TTS), explicit prosodic boundaries significantly advance the naturalness and controllability of synthesized speech. While human prosody annotation contributes a lot to the performance, it is a labor-intensive and time-consuming process, often resulting in inconsistent outcomes. Despite the availability of extensive supervised data, the current benchmark model still faces performance setbacks. To address this issue, a two-stage automatic annotation pipeline is novelly proposed in this paper. Specifically, in the first stage, we propose contrastive text-speech pretraining of Speech-Silence and Word-Punctuation (SSWP) pairs. The pretraining procedure hammers at enhancing the prosodic space extracted from joint text-speech space. In the second stage, we build a multi-modal prosody annotator, which consists of pretrained encoders, a straightforward yet effective text-speech feature fusion scheme, and a sequence classifier. Extensive experiments conclusively demonstrate that our proposed method excels at automatically generating prosody annotation and achieves state-of-the-art (SOTA) performance. Furthermore, our novel model has exhibited remarkable resilience when tested with varying amounts of data.Comment: Submitted to ICASSP 202
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