4,802 research outputs found

    Resource Allocation for Device-to-Device Communications in Multi-Cell Multi-Band Heterogeneous Cellular Networks

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    Heterogeneous cellular networks (HCNs) with millimeter wave (mm-wave) communications are considered as a promising technology for the fifth generation mobile networks. Mm-wave has the potential to provide multiple gigabit data rate due to the broad spectrum. Unfortunately, additional free space path loss is also caused by the high carrier frequency. On the other hand, mm-wave signals are sensitive to obstacles and more vulnerable to blocking effects. To address this issue, highly directional narrow beams are utilized in mm-wave networks. Additionally, device-to-device (D2D) users make full use of their proximity and share uplink spectrum resources in HCNs to increase the spectrum efficiency and network capacity. Towards the caused complex interferences, the combination of D2D-enabled HCNs with small cells densely deployed and mm-wave communications poses a big challenge to the resource allocation problems. In this paper, we formulate the optimization problem of D2D communication spectrum resource allocation among multiple micro-wave bands and multiple mm-wave bands in HCNs. Then, considering the totally different propagation conditions on the two bands, a heuristic algorithm is proposed to maximize the system transmission rate and approximate the solutions with sufficient accuracies. Compared with other practical schemes, we carry out extensive simulations with different system parameters, and demonstrate the superior performance of the proposed scheme. In addition, the optimality and complexity are simulated to further verify effectiveness and efficiency.Comment: 13 pages, 11 figures, IEEE Transactions on Vehicular Technolog

    Wearable silver nanowire dry electrodes for electrophysiological sensing

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    We present wearable dry electrodes made of silver nanowires for long-term electrophysiological sensing such as electrocardiography and electromyography

    Y(4626) as a molecular state from interaction DsDˉs1(2536)DsDˉs1(2536){D}^*_s\bar{D}_{s1}(2536)-{D}_s\bar{D}_{s1}(2536)

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    Recently, a new structure Y(4626)Y(4626) was reported by the Belle Colloboration in the process e+eDs+Ds1(2536)e^+e^-\to D_s^+D_{s1}(2536)^-. In this work, we propose an assignment of the Y(4626)Y(4626) as a DsDˉs1(2536){D}^*_s\bar{D}_{s1}(2536) molecular state, which decays into the Ds+Ds1(2536)D_s^+D_{s1}(2536)^- channel through a coupling between DsDˉs1(2536){D}^*_s\bar{D}_{s1}(2536) and DsDˉs1(2536){D}_s\bar{D}_{s1}(2536) channels. With the help of the heavy quark symmetry, the potential of the interaction DsDˉs1(2536)DsDˉs1(2536){D}^*_s\bar{D}_{s1}(2536)-{D}_s\bar{D}_{s1}(2536) is constructed within the one-boson-exchange model, and inserted into the quasipotential Bethe-Salpeter equation. The pole of obtained scattering amplitude is searched for in the complex plane, which corresponds to a molecular state from the interaction DsDˉs1(2536)DsDˉs1(2536){D}^*_s\bar{D}_{s1}(2536)-{D}_s\bar{D}_{s1}(2536). The results suggest that a pole is produced near the DsDˉs1(2536){D}^*_s\bar{D}_{s1}(2536) threshold, which exhibits as a peak in the invariant mass spectrum of the DsDˉs1(2536){D}_s\bar{D}_{s1}(2536) channel at about 4626 MeV. It obviously favors the Y(4265)Y(4265) as a DsDˉs1(2536){D}^*_s\bar{D}_{s1}(2536) molecular state. In the same model, other molecular states from the interaction DsDˉs1(2536)DsDˉs1(2536){D}^*_s\bar{D}_{s1}(2536)-{D}_s\bar{D}_{s1}(2536) are also predicted, which can be checked in future experiments.Comment: 7 pages, 2 figure

    Scoliosis Related Information on the Internet in China: Can Patients Benefit from This Information?

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    Background: There has been an increasing popularity of searching health related information online in recent years. Despite that considerable amount of scoliosis patients have shown interest in obtaining scoliosis information through Internet, previous studies have demonstrated poor quality of online information. However, this conclusion may vary depending on region and culture. Since China has a restricted Internet access outside of its borders, the aim of this study is to evaluate the quality of scoliosis information available online using recognized scoring systems and to analyze the Internet as a source of health information in China. Methods: A survey-based questionnaire was distributed to 280 respondents at outpatient clinics. Information on demographics and Internet use was collected. Binary logistic analysis was performed to identify possible predictors for the use of Internet. In addition, the top 60 scoliosis related websites assessed through 4 search engines were reviewed by a surgeon and the quality of online information was evaluated using DISCERN score and JAMA benchmark. Results: Use of the Internet as a source for scoliosis related information was confirmed in 87.8% of the respondents. College education, Internet access at home and urban residence were identified as potential predictors for Internet use. However, the quality of online scoliosis related information was poor with an average DISCERN score of 27.9±11.7 and may be misleading for scoliosis patients. Conclusion: The study outlines the profile of scoliosis patients who use the Internet as a source of health information. It was shown that 87.8% of the scoliosis patients in outpatient clinics have searched for scoliosis related information on Internet. Urban patients, higher education and Internet access at home were identified as potential predictors for Internet search. However, the overall quality of online scoliosis related information was poor and confusing. Physician based websites seemed to contain more reliable information

    Overexpression of members of the microRNA-183 family is a risk factor for lung cancer: A case control study

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    <p>Abstract</p> <p>Background</p> <p>Lung cancer is the leading cause of cancer-related deaths worldwide. Early detection is considered critical for lung cancer treatment. MicroRNAs (miRNAs) have shown promise as diagnostic and prognostic indicators. This study was to identify specific miRNAs with diagnostic and prognostic value for patients with lung cancer, and to explore the correlation between expression profiles of miRNAs and patient survival.</p> <p>Methods</p> <p>Gene expression of members of the miR-183 family (miR-96, miR-182, and miR-183) were examined in 70 paired samples from lung cancer patients (primary cancer and non-cancerous tissues and sera), as well as 44 serum samples from normal volunteers and lung cancer cell lines by quantitative real-time reverse transcription polymerase chain reaction (RT-qPCR). The correlation between the expression of miRNAs in tissues, sera, and patient overall survival were also examined by log-rank and Cox regression analysis.</p> <p>Results</p> <p>Expression levels of members of the miR-183 family in lung cancer tumor and sera were higher than that of their normal counterparts. The miR-96 expression in tumors was positively associated with its expression in sera. Log-rank and Cox regression analyses demonstrated that high expression of tumor and serum miRNAs of the miR-183 family were associated with overall poor survival in patients with lung cancer.</p> <p>Conclusions</p> <p>Our results suggest that the expressions of miR-96, miR-182, and miR-183 in tumor and sera may be considered potential novel biomarkers for the diagnosis and prognosis of lung cancer.</p
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