4,462 research outputs found

    Summertime community structure of intertidal macrobenthos in Changdao Archipelago, Shandong Province, China

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    The community structure of intertidal macrobenthos in Changdao Archipelago (north of Shandong Peninsula, between Bohai Bay and the northern Yellow Sea) was examined based on samples collected from 14 stations in five transects in June 2007. Three stations corresponding to high, medium and low tidal areas were set up for each transect. A total of 68 macrobenthic species were found in the research region, most of which belonged to Mollusca and Crustacea. The average abundance and biomass of the macrobenthos was 1383 ind./m(2) and 372.41 g/m(2), respectively. The use of an arbitrary similarity level of 20% resulted in identification of five groups among the 14 stations in the research region. There were remarkable differences in the biomass, abundance and Shannon-Wiener diversity index of the different sediments. Specifically, the order of biomass was rocky shores &gt; gravel &gt; mud-sand &gt; coarse sand &gt; stiff mud, while the order of abundance was rocky shores &gt; coarse sand &gt; mud-sand &gt; gravel &gt; stiff mud, and that of the diversity index was mud-sand &gt; gravel &gt; stiff mud &gt; rocky shores &gt; coarse sand. The above results revealed that the sediment type was the most important factor affecting the structure of the macrobenthic community of the intertidal zone.</p

    A novel self-routing scheme for all-optical packet switched networks with arbitrary topology

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    Due to limited available photonic devices, optical networks in the near future will likely employ routing schemes that do not require sophisticated processing of optical packets. In this paper, we propose a novel self-routing scheme for all-optical packet networks that can be applied to networks with arbitrary topology. The proposed routing scheme requires only single bit processing and can be implemented with existing technologies.published_or_final_versio

    A novel self-routing address scheme for all-optical packet-switched networks with arbitrary topologies

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    Pure all-optical packet-switched networks in which both header processing and packet routing are carried out in the optical domain overcome the bandwidth bottlenecks of optoelectronic conversions and therefore are expected to meet the needs of next generation high speed networks. Due to the limited capabilities of available optical logic devices, realizations of pure all-optical packet-switched networks in the near future will likely employ routing schemes that minimize the complexity of routing control. In this paper, we propose a novel self-routing scheme that identifies the output ports of the nodes in a network instead of the nodes themselves. The proposed address scheme requires single bit processing only and is applicable to small to medium size pure all-optical packet-switched networks with arbitrary topologies. Unlike traditional self-routing schemes, multiple paths between two nodes can be defined. Hierarchical address structure can be used in the proposed routing scheme to shorten the address.published_or_final_versio

    Deflection routing in slotted self-routing networks with arbitrary topology

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    A deflection routing algorithm that can be applied to a novel self-routing address scheme for networks with arbitrary topology is proposed. The proposed deflection routing algorithm can be implemented all-optically using bitwise optical logic gates. Besides the primary output link selection, alternate output link choices by a packet at each node in case of deflection are also encoded in the address header. Priority classes can also be defined in the proposed address scheme. The performance of the deflection routing algorithm is studied using the AT&T North America OC-48 optical fiber network topology.published_or_final_versio

    Multicasting in deflection-routed all-optical packet-switched networks

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    Two multicast protocols are proposed for deflection-routed all-optical packet-switched networks. One scheme sends a deflected multicast packet back to the root node while the other sends it back to the deflection point Both schemes can be implemented using demonstrated optical signal processing technology. The performance of the two proposed multicast schemes are compared using Manhattan Street Networks. We found that the back-to-the-root-node scheme performed better than the back-to-the-deflection-node scheme. A hybrid approach can further improve the system performance.published_or_final_versio

    ASIC3 Channels Integrate Agmatine and Multiple Inflammatory Signals through the Nonproton Ligand Sensing Domain

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    <p>Abstract</p> <p>Background</p> <p>Acid-sensing ion channels (ASICs) have long been known to sense extracellular protons and contribute to sensory perception. Peripheral ASIC3 channels represent natural sensors of acidic and inflammatory pain. We recently reported the use of a synthetic compound, 2-guanidine-4-methylquinazoline (GMQ), to identify a novel nonproton sensing domain in the ASIC3 channel, and proposed that, based on its structural similarity with GMQ, the arginine metabolite agmatine (AGM) may be an endogenous nonproton ligand for ASIC3 channels.</p> <p>Results</p> <p>Here, we present further evidence for the physiological correlation between AGM and ASIC3. Among arginine metabolites, only AGM and its analog arcaine (ARC) activated ASIC3 channels at neutral pH in a sustained manner similar to GMQ. In addition to the homomeric ASIC3 channels, AGM also activated heteromeric ASIC3 plus ASIC1b channels, extending its potential physiological relevance. Importantly, the process of activation by AGM was highly sensitive to mild acidosis, hyperosmolarity, arachidonic acid (AA), lactic acid and reduced extracellular Ca<sup>2+</sup>. AGM-induced ASIC3 channel activation was not through the chelation of extracellular Ca<sup>2+ </sup>as occurs with increased lactate, but rather through a direct interaction with the newly identified nonproton ligand sensing domain. Finally, AGM cooperated with the multiple inflammatory signals to cause pain-related behaviors in an ASIC3-dependent manner.</p> <p>Conclusions</p> <p>Nonproton ligand sensing domain might represent a novel mechanism for activation or sensitization of ASIC3 channels underlying inflammatory pain-sensing under <it>in vivo </it>conditions.</p

    Effect of Scopoletin on Apoptosis and Cell Cycle Arrest in Human Prostate Cancer Cells In vitro

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    Purpose: To investigate the anticancer activity of scopoletin against human prostate cancer.Methods: The anticancer activity of scopoletin was evaluated by 3-(4, 5-dimethylthiazol-2-yl)-2, 5- diphenyltetrazolium bromide (MMT) assay. Flow cytometry using propidium iodide and annexin V-FITC was employed to study apoptosis and cell cycle analysis. Hoechst 33258 staining was used to assess the effect of scopoletin on cell morphology and apoptotic body formation in human prostate carcinoma (LNCaP) cells via Florescence microscopy and finally Western blotting was used to evaluate the effect of scopoletin on cyclin D1 and cyclin B1 expressions.Results: Scopoletin induced a dose-dependent growth inhibition in LNCaP prostate cancer cells. It induced G2/M phase growth arrest and led to an increase in the sub-G0/G1 cell population after treatment with increasing doses compared to control cells, scopoletin treatment resulted in cell shrinkage along with membrane blebbing which are characteristic features of cell apoptosis. Approximately 15.45, 32.6 and 21.71 % of the cells underwent early apoptosis after treatment with 40, 80 and 100 μM of scopoletin respectively. Cyclin D expression diminished in a concentration-dependent manner when LNCaP cells were treated with different concentrations of scopoletin.Conclusion: These results reveal that scopoletin may be used as a natural chemotherapeutic agent against prostate cancer.Keywords: Prostate cancer, Apoptosis, Cell cycle analysis, Scopoletin, Flow cytometry, Fluorescence microscop

    Using 2x2 switching modules to build large 2-D MEMS optical switches

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    MEMS optical switch technology is one of the key technologies in wavelength division multiplexing (WDM) optical networks. Although the 2-D MEMS optical switch technology is mature, the commonly used crossbar architecture is not amenable to building large switches. In this paper, we propose a design of 2x2 switching modules, and use it to build large 2-D MEMS optical switches with architectures such as Spanke-Benes and Benes networks.published_or_final_versio
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