237 research outputs found

    On the Performance of Beam Allocation Based Multi-User Massive MIMO Systems

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    Safety and efficacy of a novel double-lumen tracheal tube in neonates with RDS: A prospective cohort study

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    BackgroundThe purpose of this study was to assess the safety and efficacy of a new double-lumen tracheal tube for neonates, with a conventional tracheal tube as a control.MethodNewborns with respiratory distress syndrome (RDS) requiring endotracheal intubation admitted to the tertiary neonatal intensive care unit (NICU) of Qujing Maternal and Child Healthcare Hospital in Yunnan Province between March 2021 and May 2022 were enrolled in this prospective cohort study. Outcome indicators related to effectiveness included mainly the number of intubations, duration of ventilation, duration of oxygenation, and length of stay; safety indicators included any clinical adverse effects during and after intubation. Appropriate stratified and subgroup analyses were performed according to the purpose of intubation, gestational age, and whether the drug was administered via endotracheal tube.ResultA total of 101 neonates were included and divided into two groups based on the choice of tracheal tube: the conventional (n = 50) and new (n = 51) tracheal tube groups. There was no statistical difference between the two groups in terms of adverse effects during and after intubation (p > 0.05). In neonates who were mechanically ventilated without endotracheal surfactant therapy or newborns receiving InSurE technique followed by non-invasive ventilation, no significant differences were found between the two groups regarding any of the efficacy indicators (p > 0.05). However, for neonates on invasive mechanical ventilation, the new tracheal tube allowed for a significant reduction in the duration of mechanical ventilation (96.50[74.00, 144.00] vs. 121.00[96.00, 196.50] hours, p = 0.037) and total ventilation (205.71 ± 80.24 vs. 277.56 ± 117.84 h, p = 0.027), when used as a route for endotracheal drug delivery. Further analysis was performed according to gestational age for newborns requiring intratracheal surfactant administration during mechanical ventilation, and the data showed that for preterm infants, the new tracheal tube not only shortened the duration of mechanical ventilation (101.75 ± 39.72 vs. 155.50 ± 51.49 h, p = 0.026) and total ventilation (216.00 ± 81.60 vs. 351.50 ± 113.79 h, p = 0.010), but also demonstrated significant advantages in reducing the duration of oxygen therapy (9.75 ± 6.02 vs. 17.33 ± 8.43 days, p = 0.042); however, there was no statistical difference in efficacy outcomes between the two groups in full-term infants (p > 0.05).ConclusionThe efficacy and safety of this new tracheal tube are promising in neonates with RDS, especially those requiring surfactant administration via a tracheal tube during mechanical ventilation. Given the limitations of this study, however, the clinical feasibility of this catheter needs to be further confirmed in prospective randomized trials with larger sample sizes.Clinical Trial Registrationhttp://www.chictr.org.cn/showproj.aspx?proj=12207

    Synthesis and cytotoxicity of a biotinylated CC-1065 analogue

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    BACKGROUND: The use of pretargeting technology for cancer imaging and treatment has made significant progress in the last few years. This approach takes advantage of the fact that biotin binds strongly to proteins avidin and streptavidin. Thus, a non-toxic tumor cell specific antibody is conjugated with avidin/streptavidin, and is administered to patients. After the antibody binds to tumor cells (usually 24–48 h); a clearing agent is given to remove the residual circulating antibodies in blood. Lastly, a toxic biotin-radioisotope conjugate is administered. Due to the small size of the biotin-radioisotope molecule and tight binding between biotin and avidin/streptavidin, the biotin-radioisotope rapidly binds to tumor cells with high specificity. CC-1065 (1) is one of a few classes of extremely potent antitumor agents, and a biotinalyted CBI-bearing CC-1065 analogue is a promising candidate to be used in the pretargeting technology to treat cancer. RESULTS: A biotinalyted CBI-bearing CC-1065 analogue, 6, was synthesized. The IC(50) of 6 was 0.7 nM against U937 cells. Compound 6 caused apototsis of U937 cells. CONCLUSIONS: For the first time, a biotinalyted CBI-bearing CC-1065 analogue, 6, was synthesized. The biotinylated 6 can serve as a model compound to explore the usefulness of non-radioactive small molecule anticancer drugs in the pretargeting strategy for cancer imaging and therapy

    Synthesis and preliminary cytotoxicity study of a cephalosporin-CC-1065 analogue prodrug

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    BACKGROUND: Antibody-directed enzyme prodrug therapy (ADEPT) is a promising new approach to deliver anticancer drugs selectively to tumor cells. In this approach, an enzyme is conjugated to a tumor-specific antibody. The antibody selectively localizes the enzyme to the tumor cell surface. Subsequent administration of a prodrug substrate of the enzyme leads to the enzyme-catalyzed release of the free drug at the tumor site. The free drug will destroy the tumor cells selectively, thus, reducing side effects. RESULTS: A CC-1065 analogue was conjugated to a cephalosporin affording prodrug 2. The prodrug and its corresponding free drug, 1, have IC(50) values of 0.9 and 0.09 nM, respectively, against U937 leukemia cells in vitro. CONCLUSIONS: For the first time, a prodrug comprised of a cephalosporin and a CC-1065 analogue has been synthesized. The preliminary in vitro studies show that the prodrug was 10-fold less toxic than the free drug. Prodrug 2 has the potential to be useful in cancer treatment using the ADEPT approach

    A Sensitive Film Structure Improvement of Reduced Graphene Oxide Based Resistive Gas Sensors

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    This study was focused on how to improve the gas sensing properties of resistive gas sensors based on reduced graphene oxide. Sol-airbrush technology was utilized to prepare reduced graphene oxide films using porous zinc oxide films as supporting materials mainly for carbon dioxide sensing applications. The proposed film structure improved the sensitivity and the response/recovery speed of the sensors compared to those of the conventional ones and alleviated the restrictions of sensors\u27 performance to the film thickness. In addition, the fabrication technology is relatively simple and has potential for mass production in industry. The improvement in the sensitivity and the response/recovery speed is helpful for fast detection of toxic gases or vapors in environmental and industrial applications

    Resource Allocation and Performance Analysis of Cellular-assisted OFDMA Device-to-Device Communications

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    Resource allocation of cellular-assisted device-todevice (D2D) communication is very challenging when frequency reuse is considered among multiple D2D pairs within a cell, as intense inter D2D interference is difficult to tackle and generally causes extremely large signaling overhead for channel state information (CSI) acquisition. In this paper, a novel resource allocation framework for cellular-assisted D2D communication is developed with low signaling overhead while maintaining high system capacity. By utilizing the spatial dispersion property of D2D pairs, a geography-based sub-cell division strategy is proposed to divide the cell into multiple sub-cells and D2D pairs within one sub-cell are formed into one group. Then, sub-cell resource allocation is performed independently among sub-cells without the need of any prior knowledge of inter D2D interference. Under the proposed resource allocation framework, a tractable approximation for the inter D2D interference modelling is obtained and a computationally efficient expression for the average ergodic sum capacity of the cell is derived. The expression further allows us to obtain the optimal number of sub-cells, which is an important parameter for maximizing the average ergodic sum capacity of the cell. It is shown that with small CSI feedback, system capacity can be improved significantly by adopting the proposed resource allocation framework, especially in dense D2D deployed systems
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