140 research outputs found

    Optimum Multi-hop Transmission Strategies for Energy Constrained Wireless Sensor Networks

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    This paper presents optimum multi-hop transmission strategies (MHTS) for energy constrained wireless sensor networks (WSNs). Nodes in a multi-hop WSN need to transmit their own information and to relay each other\u27s information to a base station (BS), and there are usually multiple available paths between a node and the BS. the optimum MHTS derived in this paper answers three questions: 1) how should a node divide its limited energy between the transmission of the self-information and the relay-information? 2) whether a single path or a combination of multiple paths should be used to route the information from a node to the BS? and 3) if multi-path routing is used, how should a single data stream be divided among the multiple paths? the answers to these questions are obtained by minimizing the energy per bit, or equivalently, by maximizing the amount of information delivered to the BS under certain energy constraints. Two different scheduling strategies are considered, the fair equal information strategy that requires all the nodes deliver the same amount of information to the BS, and the unfair maximum information strategy that maximizes the total amount of information delivered to the BS. the optimum MHTS for these two strategies are derived, with either convex optimization or analytical expressions, under a per node energy constraint and a total energy constraint, respectively. © 2012 IEEE

    Hardware Emulation of Wideband Correlated Multiple-input Multiple-output Fading Channels

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    A low-complexity hardware emulator is proposed for wideband, correlated, multiple-input multiple-output (MIMO) fading channels. the proposed emulator generates multiple discrete-time channel impulse responses (CIR) at the symbol rate and incorporates three types of correlation functions of the subchannels via Kronecker product: The spatial correlation between transmit or receive elements, temporal correlation due to Doppler shifts, and inter-tap correlation due to multipaths. the Kronecker product is implemented by a novel mixed parallel-serial (mixed P-S) matrix multiplication method to reduce memory storage and to meet the real-time requirement in high data-rate, large MIMO size, or long CIR systems. We present two practical MIMO channel examples implemented on an Altera Stratix III EP3SL150F FPGA DSP development kit: A 2-by-2 MIMO WiMAX channel with a symbol rate of 1.25 million symbols/second and a 2-by-6 MIMO underwater acoustic channel with 100-tap CIR. Both examples meet real-time requirement using only 12?14% of hardware resources of the FPGA. © Springer Science Business Media, LLC 2011

    Unveiling the link between systemic inflammation markers and cognitive performance among older adults in the US: A population-based study using NHANES 2011–2014 data

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    Purpose: This study aimed to evaluate the association between systemic inflammation markers and cognitive performance among older US adults. Methods: This cross-sectional study assessed 3,632 older participants from the 2011–2014 National Health and Nutrition Examination Survey (NHANES). The main analysis included participants aged over 60 years. Systemic inflammation markers were quantified by calculating the composite inflammation indicators from the blood routine count, and cognitive performance was assessed using Consortium to Establish a Registry for Alzheimer\u27s Disease (CERAD) test, Animal Fluency test (AFT), and Digit Symbol Substitution test (DSST). Results: There were 2,743 individuals enrolled in the current analysis. The overall mean age was 64.9 years and 48.7 % were males. The levels of SIRI and PIV were significant negative associated with scores of CERAD, CERAD delayed recall, and DSST in the unadjusted models. Moreover, SII were significant negative associated with scores of CERAD and CERAD delayed recall. After adjusting the covariates of demographics, lifestyle factors, history of chronic diseases and BMI, significant negative association were observed between systematic inflammation markers and cognitive performance. Additionally, a progressive and significant decrease in the score of cognitive performance assessments with the increased levels of SIRI, SII, and PIV were respectively observed. Finally, the correlation between systemic inflammation markers and cognitive performance were evidenced in the sensitive analysis. Conclusion: Findings support a strong inverse correlation between systemic inflammation markers and cognitive performance, suggesting that addressing inflammation could be a promising avenue for enhancing cognitive health and mitigating age-related cognitive decline

    Aberrant expression of decoy receptor 3 in human breast cancer: relevance to lymphangiogenesis

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    AbstractBackgroundDecoy receptor 3 (DcR3), a decoy receptor against Fas ligand belonging to the tumor necrosis factor receptor superfamily, is overexpressed in some forms of cancer. It was recently reported that DcR3 could protect endothelial cells from apoptosis, implying a potential role in the development of vessels, whereas its role in the lymphangiogenesis remains unclear. In the present study, we studied the DcR3 expression and its relationship with the lymphatic microvessel density (LMVD) to investigate if it played a role in the lymph metastasis of human breast cancer.Materials and methodsReal-time polymerase chain reaction and immunohistochemistry were performed to measure the messenger RNA and protein expression of DcR3 in the breast cancer tissues, noncancerous counterparts, and axillary lymph node from 63 patients. LMVD in these specimens was assessed by counting the D2-40 labeled–microvessels. Furthermore, the correlations between DcR3 expression and LMVD and other clinicopathologic parameters were analyzed.ResultsDcR3 was overexpressed in the breast cancer tissue of 58 patients (92.1%) and was also expressed in vascular endothelial cells and tumor cells in the lymph nodes. LMVD in cancer tissue and lymph nodes were both positively correlated to the aberrant expression of DcR3.ConclusionsThe relevance between DcR3 overexpression and LMVD revealed the existence of possible links between DcR3 and lymphangiogenesis. Based on these findings, it is important to further explore the regulation of lymphangiogenesis operated by the reverse tumor necrosis factor signaling of DcR3

    MAPK1 promotes the metastasis and invasion of gastric cancer as a bidirectional transcription factor

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    Background: The Mitogen-activated protein kinase 1 (MAPK1) has both independent functions of phosphorylating histones as a kinase and directly binding the promoter regions of genes to regulate gene expression as a transcription factor. Previous studies have identified elevated expression of MAPK1 in human gastric cancer, which is associated with its role as a kinase, facilitating the migration and invasion of gastric cancer cells. However, how MAPK1 binds to its target genes as a transcription factor and whether it modulates related gene expressions in gastric cancer remains unclear. Results: Here, we integrated biochemical assays (protein interactions and chromatin immunoprecipitation (ChIP)), cellular analysis assays (cell proliferation and migration), RNA sequencing, ChIP sequencing, and clinical analysis to investigate the potential genomic recognition patterns of MAPK1 in a human gastric adenocarcinoma cell-line (AGS) and to uncover its regulatory effect on gastric cancer progression. We confirmed that MAPK1 promotes AGS cells invasion and migration by regulating the target genes in different directions, up-regulating seven target genes (KRT13, KRT6A, KRT81, MYH15, STARD4, SYTL4, and TMEM267) and down-regulating one gene (FGG). Among them, five genes (FGG, MYH15, STARD4, SYTL4, and TMEM267) were first associated with cancer procession, while the other three (KRT81, KRT6A, and KRT13) have previously been confirmed to be related to cancer metastasis and migration. Conclusion: Our data showed that MAPK1 can bind to the promoter regions of these target genes to control their transcription as a bidirectional transcription factor, promoting AGS cell motility and invasion. Our research has expanded the understanding of the regulatory roles of MAPK1, enriched our knowledge of transcription factors, and provided novel candidates for cancer therapeutics

    Fluid computational model for mineral and vegetal pigments diffusing in Chinese color-ink painting

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    In this paper, simulation of artistic vegetable and mineral pigments diffusing effects of Chinese color-ink painting is presented, using a novel physical model according to the Second Fick's diffusing law and Brownian motion theory. Due to the fact that generation of most art effects depends on complicated pigment-water motion simulation such as diffusing and pigment mixing on and under traditional fabric cotton paper (Xuan paper) surface, the proposed model is found effective for simulating the pigment-water motion in art creating process. Implemented on the GPU, the simulation operations in our system can be accomplished in a real-time manner. The effectiveness of the proposed techniques is validated in our developed Digital Painting System, where various art effects can be successfully re-produced including the Initial area-Darkened initial edge-Diffusion area Lightened diffusion edge (IDDL) effect for vegetable pigments, the Initial area-Darkened initial edge-Diffusion area-Darkened diffusion edge (IDDD) effect for mineral pigments, and multistroke superimposing effects and achieves. In addition, quantitative evaluation is also introduced and shows superior performance of the proposed model in comparison with state-of-the-art techniques

    DNA-directed nanofabrication of high-performance carbon nanotube field-effect transistors

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    生物自组装结构具有精细的三维形貌,其关键结构参数小于光刻等传统纳米加工手段的分辨率极限。利用自组装的生物分子为加工模板,已经实现了金属、碳基、氧化物等材料的形貌可控合成。然而,基于生物模板的电学器件,其性能往往远落后于通过蚀刻或薄膜方法制备的同类器件,并且缺乏长程取向规整性,制约了生物模板在高性能器件中的应用。针对上述挑战,我校化学化工学院朱志教授课题组与北京大学孙伟研究员课题组、清华大学唐建石研究员课题组、美国国家标准与技术研究院郑明博士合作,探索了生物-碳纳米管复合界面及大面积取向排列的调控新方法。北京大学孙伟研究员团队长期从事核酸引导的精准纳米组装研究,厦门大学朱志教授团队长期从事微纳加工及微流控研究,双方紧密合作,优势互补,联合清华大学和美国国家标准与技术研究院等多团队联合攻关完成该工作。共同第一作者厦门大学化学化工学院2011协同创新中心博士研究生陈雅鸿负责了碳纳米管组装及大面积阵列化工作,孙伟研究员和朱志教授为论文的共同通讯作者。Biofabricated semiconductor arrays exhibit smaller channel pitches than existing lithographic feasibility. However, the metal ions within biolattices and the submicrometer dimensions of typical biotemplates result in both poor transport performance and small array uniformity. Using DNA-templated parallel carbon nanotube (CNT) arrays as model systems, we developed a rinsing-after-fixing approach to improve the key transport performance metrics by more than a factor of 10 folds over previous biotemplated field-effect transistors. We also used spatially confined placement of assembled CNT arrays within polymethyl methacrylate cavities to demonstrate centimeter-scale alignment. At the interface of high-performance electronics and biomolecular self-assembly, current approaches may enable scalable biotemplated electronics sensitive to local biological environments.W.S.,M.Z., Y.C., K.W., and Z.Z. acknowledge the National Science Foundation of China (Grant No. 21875003, 21991134, and 61621061) and PKU for financial support. Y.C., C.Y., and Z.Z. acknowledge the National Science Foundation of China (Grant No. 21775128, 21435004, and 21974113) for financial support. J.K.S., J.A.F., and M.Z. acknowledge NIST internal fund. 该研究工作得到国家自然科学基金等资助
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