120 research outputs found
Received Signal Strength Indicator-Based Adaptive Localization Algorithm for Indoor Wireless Sensor Networks
Solutions for indoor localization have become more critical with recent advancement in context and location-aware technologies. When wireless sensor network (WSN) used in complex indoor environment, great propagation loss will be caused and it is very difficult to estimate adaptively the location of target nodes when environment changed. In this paper, an indoor adaptive localization algorithm based on received signal strength indication (RSSI) for wireless sensor networks is proposed. The algorithm utilizes the RSSI of radio signals radiating from two other fixed nodes to generate the local parameters of signal propagation model for each fixed node, and the parameters are updated online according to environmental variation. According to the estimated parameters of the signal propagation model, iteration method is applied to estimate the position of target node. Through actual experimental tests, the validity of the proposed algorithm is demonstrated
Toxicity of microcystins in the isolated hepatocytes of common carp (Cyprinus carpio L.)
The toxicity of hepatotoxic microcystins produced mainly by Microcystis aeruginosa in mammals and fishes was well studied in recent years. However, there were scarcely reports in toxic effects of microcystins on isolated hepatocytes of fishes, especially investigation of microcystin-induced apoptosis and/or necrosis in carp hepatocytes. In the present study, the isolated hepatocytes of common carp were exposed to various concentrations of microcystins (0.01, 0.1, 1, 10, 100, 1000 mu g L-1) for 2, 4, 8, 16 and 24 h, respectively, and cytotoxicity of microcystins in the toxin-treated cells was determined. Results of this study showed that cytotoxicity of microcystins on carp hepatocytes was time and dose-dependent, and the approximate LC50 of microcystins in carp hepatocytes was 169.2 mu g L-1. The morphological changes typical of apoptosis, such as blebbing of cell membrane, condensation and fragmentation of cell nucleus were observed in the hepatocytes exposed to microcystins (1, 10 and 100 mu g L-1) using fluorescence and differential interference contrast microscopy. Agarose gel electrophoresis of DNA demonstrated a typical apoptotic "ladder pattern" in microcystin-treated hepatocytes after 16 h of exposure. Results of the present study indicated that the form of cell death in microcystin-treated hepatocytes depend on the exposure dose of toxin. When lower concentration of microcystins (10 and 100 mu g L-1) was used for exposure, carp hepatocytes died in apoptosis while, when higher one used (1000 mu g L-1), they died in the form of necrosis. (C) 2006 Elsevier Inc. All rights reserved.The toxicity of hepatotoxic microcystins produced mainly by Microcystis aeruginosa in mammals and fishes was well studied in recent years. However, there were scarcely reports in toxic effects of microcystins on isolated hepatocytes of fishes, especially investigation of microcystin-induced apoptosis and/or necrosis in carp hepatocytes. In the present study, the isolated hepatocytes of common carp were exposed to various concentrations of microcystins (0.01, 0.1, 1, 10, 100, 1000 mu g L-1) for 2, 4, 8, 16 and 24 h, respectively, and cytotoxicity of microcystins in the toxin-treated cells was determined. Results of this study showed that cytotoxicity of microcystins on carp hepatocytes was time and dose-dependent, and the approximate LC50 of microcystins in carp hepatocytes was 169.2 mu g L-1. The morphological changes typical of apoptosis, such as blebbing of cell membrane, condensation and fragmentation of cell nucleus were observed in the hepatocytes exposed to microcystins (1, 10 and 100 mu g L-1) using fluorescence and differential interference contrast microscopy. Agarose gel electrophoresis of DNA demonstrated a typical apoptotic "ladder pattern" in microcystin-treated hepatocytes after 16 h of exposure. Results of the present study indicated that the form of cell death in microcystin-treated hepatocytes depend on the exposure dose of toxin. When lower concentration of microcystins (10 and 100 mu g L-1) was used for exposure, carp hepatocytes died in apoptosis while, when higher one used (1000 mu g L-1), they died in the form of necrosis. (C) 2006 Elsevier Inc. All rights reserved
MiR-770-5p inhibits cisplatin chemoresistance in human ovarian cancer by targeting ERCC2
In this study, we examined the role of the miRNA miR-770-5p in cisplatin chemotherapy resistance in ovarian cancer (OVC) patients. miR-770-5p expression was reduced in platinum-resistant patients. Using a 6.128-fold in expression as the cutoff value, miR-770-5p expression served as a prognostic biomarker and predicted the response to cisplatin treatment and survival among OVC patients. Overexpression of miR-770-5p in vitro reduced survival in chemoresistant cell lines after cisplatin treatment. ERCC2, a target gene of miR-770-5p that participates in the NER system, was negatively regulated by miR-770-5p. siRNA-mediated silencing of ERCC2 reversed the inhibition of apoptosis resulting from miR-770-5p downreglation in A2780S cells. A comet assay confirmed that this restoration of cisplatin chemosensitivity was due to the inhibition of DNA repair. These findings suggest that endogenous miR-770-5p may function as an anti-oncogene and promote chemosensitivity in OVC, at least in part by downregulating ERCC2. miR-770-5p may therefore be a useful biomarker for predicting chemosensitivity to cisplatin in OVC patients and improve the selection of effective, more personalized, treatment strategies
Crystal structure of 2-(2-naphthyl)-4,6-dimethylpyrimidine, C(16)H(14)N(2)
C(16)H(14)N(2), monoclinic, P12(1)/c1 (no. 14), a = 8.387(1) angstrom, b = 17.453(3) angstrom, c = 8.694(1) angstrom, beta = 93.092(2)degrees, V = 1270.8 angstrom(3), Z = 4, R(gt)(F) = 0.046, wR(ref)(F(2)) = 0.129, T = 294 K.program for innovation of science and technology talents of Henan Province[104200510022]; program for science and technology leaders of Zhengzhou City[10LJRC174]; Doctor Foundation[D09004]; program for innovative research team of Henan Institute of Engineering[2009IRTHNIE05
Plasticity performance of Al0.5CoCrCuFeNi high-entropy alloys under nanoindentation
The statistical and dynamic behaviors of the displacement-load curves of a high-entropy alloy Al0.3CoCrCuFeNi were analyzed for the nanoindentation performed at two temperatures. Critical behavior of serrations at room temperature and chaotic flows at 200 degrees C were detected. These results are attributed to the interaction among a large number of slip hands. For the nanoindentation at room temperature recurrent partial events between slip hands introduce a hierarchy of length scales leading to a critical state. For the nanoindentation at 200 degrees C there is no spatial interference between two slip hands which is corresponding to the evolution of separated trajectory of chaotic behavior
Life cycle assessment of energy consumption and environmental emissions for cornstalk-based ethyl levulinate
This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.This study analysed the sustainability of fuel-ethyl levulinate (EL) production along with furfural, as a by-product, from cornstalk in China. A life cycle assessment (LCA) was conducted using the SimaPro software to evaluate the energy consumption (EC), greenhouse gas (GHG) and criteria emissions, from cornstalk growth to EL utilisation. The total life cycle EC was found to be 4.54MJ/MJ EL, of which 94.7% was biomass energy. EC in the EL production stage was the highest, accounting for 96.8% of total EC. Fossil EC in this stage was estimated to be 0.095 MJ/MJ, which also represents the highest fossil EC throughout the life cycle (39.5% of the total). The ratio of biomass to fossil EC over the life cycle was 17.9, indicating good utilisation of renewable energy in cornstalk-based EL production. The net life cycle GHG emissions were 96.6 g CO2-eq/MJ. The EL production stage demonstrated the highest GHG emissions, representing 53.4% of the total positive amount. Criteria emissions of carbon monoxide (CO) and particulates ≤ 10 um (PM10) showed negative values, of -3.15 and -0.72 g/MJ, respectively. Nitrogen oxides (NOx) and sulphur dioxide (SO2) emissions showed positive values of 0.33 and 0.28 g/MJ, respectively, mainly arising from the EL production stage. According to the sensitivity analysis, increasing or removing the cornstalk revenue in the LCA leads to an increase or decrease in the EC and environmental emissions while burning cornstalk directly in the field results in large increases in emissions of NMVOC, CO, NOx and PM10 but decreases in fossil EC, and SO2 and GHG emissions.This study was supported by the National Natural Science Foundation of China (51506049), the National High Technology Research and Development Program of China (863 Program) (2012AA051802) and the Henan Province Foundation and Advanced Technology Research Project (132300413218)
The archaeometry and archaeology of ancient Chinese glass: a review
This paper provides a new review of archaeometric research carried out on glass found in China, set in an archaeological context, from its earliest occurrence, to the Song dynasty. It is set within a broad geographical context taking the terrestrial and maritime Silk Road contacts into account. We discuss chemical and isotopic compositional contrasts in glasses from different periods found in different parts of China, the glasses that were almost certainly made in China and those that were imported. A theme that runs through the paper is the problem of provenancing glass found in China. We discuss the glass artefacts that are of typical Chines types and contrast these with imports. The structure reflects the contrast between imported and Chinese made with glasses. We discuss potential new scientific and archaeological approaches to Chinese glass
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