185 research outputs found

    Freshness-aware Resource Allocation for Non-orthogonal Wireless-powered IoT Networks

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    This paper investigates a wireless-powered Internet of Things (IoT) network comprising a hybrid access point (HAP) and two devices. The HAP facilitates downlink wireless energy transfer (WET) for device charging and uplink wireless information transfer (WIT) to collect status updates from the devices. To keep the information fresh, concurrent WET and WIT are allowed, and orthogonal multiple access (OMA) and non-orthogonal multiple access (NOMA) are adaptively scheduled for WIT. Consequently, we formulate an expected weighted sum age of information (EWSAoI) minimization problem to adaptively schedule the transmission scheme, choosing from WET, OMA, NOMA, and WET+OMA, and to allocate transmit power. To address this, we reformulate the problem as a Markov decision process (MDP) and develop an optimal policy based on instantaneous AoI and remaining battery power to determine scheme selection and transmit power allocation. Extensive results demonstrate the effectiveness of the proposed policy, and the optimal policy has a distinct decision boundary-switching property, providing valuable insights for practical system design

    In vitro pharmacokinetics of sirolimus-coated stent for tracheal stenosis

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    Purpose: To investigate the in vitro pharmacokinetics of sirolimus-coated stent for tracheal stenosisMethods: Naked nickel titanium alloy stent was placed in methylene chloride leaching solution with different ratios of sirolimus/poly(lactic-co-glycolic acid) (PLGA). The morphology, thickness, and pellicles on the surface of the stent were observed by scanning electronic microscopy. Drug release from the stent was determined by enzyme amplification immunoassay.Results: Sirolimus was smoothly and uniformly attached to the stent, with an optimal sirolimus: PLGA coating ratio of 1:10. Further increases in sirolimus: PLGA ratio did not improve stent drug loading. A slow release of sirolimus from the stent was observed in the first week, followed by a rapid release and then much slower release process. Release of sirolimus persisted in the stent throughout the period of 42 days.Conclusion: The sirolimus-coated stent has a good surface morphology, and sustained and effective drug release characteristics. Thus, it may be effective and safe for use in the treatment of tracheal stenosis in vivo.Keywords: Tracheal stenosis, Sirolimus, Drug-coated stents, poly(lactic-co glycolic acid) PLG

    MicroRNA-143 Targets MACC1 to Inhibit Cell Invasion and Migration in Colorectal cancer

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    <p>Abstract</p> <p>Background</p> <p>MicroRNAs (miRNAs) have been suggested to play a vital role in tumor initiation and progression by negatively regulating oncogenes and tumor suppressors. Quite recently, studies have identified some miRNAs operating to promote or suppress tumor invasion or metastasis via regulating metastasis-related genes, providing potential therapeutic targets on anti-metastasis strategy. Metastasis-associated in colon cancer-1 (MACC1) has been newly identified to express highly in colorectal cancer (CRC) and promote tumor metastasis through transactivating metastasis-inducing HGF/MET signaling pathway. In this study, we investigated whether miRNA 143 is involved in the regulation of MACC1 and thus plays a functional role in CRC.</p> <p>Results</p> <p>Using both in silico prediction and western blot assay, we found the previously reported tumor suppressive miR-143 targeted MACC1 in CRC. The direct interaction between them was confirmed by 3' UTR luciferase reporter gene. In concordance with the inhibitory effects induced by siRNA mediated knockdown of MACC1, restoration of miR-143 by mimics in SW620 cells significantly attenuated cell growth, migration and invasion. It is notable that combined treatment of miR-143 mimics and MACC1 siRNA induced synergistic inhibitory effects compared to either miR-143 mimics or MACC1 siRNA treatment alone. Conversely, reduction of miR-143 by inhibitors in SW480 cells apparently stimulated these phenotypes. Furthermore, we observed that miR-143 level was inversely correlated with MACC1 mRNA expression in CRC tissues.</p> <p>Conclusions</p> <p>Our findings newly described miR-143/MACC1 link and provided a potential mechanism for MACC1 dysregulation and contribution to CRC cell invasion. It may help to estimate the therapeutic utility of miR-143 in CRC.</p

    Development of one-step SYBR Green real-time RT-PCR for quantifying bovine viral diarrhea virus type-1 and its comparison with conventional RT-PCR

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    Background Bovine viral diarrhea virus (BVDV) is a worldwide pathogen in cattle and acts as a surrogate model for hepatitis C virus (HCV). One-step real-time fluorogenic quantitative reverse transcription polymerase chain reaction (RT-PCR) assay based on SYBR Green I dye has not been established for BVDV detection. This study aims to develop a quantitative one-step RT-PCR assay to detect BVDV type-1 in cell culture. Results One-step quantitative SYBR Green I RT-PCR was developed by amplifying cDNA template from viral RNA and using in vitro transcribed BVDV RNA to establish a standard curve. The assay had a detection limit as low as 100 copies/ml of BVDV RNA, a reaction efficiency of 103.2%, a correlation coefficient (R2) of 0.995, and a maximum intra-assay CV of 2.63%. It was 10-fold more sensitive than conventional RT-PCR and can quantitatively detect BVDV RNA levels from 10-fold serial dilutions of titrated viruses containing a titer from 10-1 to 10-5 TCID50, without non-specific amplification. Melting curve analysis showed no primer-dimers and non-specific products. Conclusions The one-step SYBR Green I RT-PCR is specific, sensitive and reproducible for the quantification of BVDV in cell culture. This one-step SYBR Green I RT-PCR strategy may be further optimized as a reliable assay for diagnosing and monitoring BVDV infection in animals. It may also be applied to evaluate candidate agents against HCV using BVDV cell culture model

    Development of one-step SYBR Green real-time RT-PCR for quantifying bovine viral diarrhea virus type-1 and its comparison with conventional RT-PCR

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    <p>Abstract</p> <p>Background</p> <p>Bovine viral diarrhea virus (BVDV) is a worldwide pathogen in cattle and acts as a surrogate model for hepatitis C virus (HCV). One-step real-time fluorogenic quantitative reverse transcription polymerase chain reaction (RT-PCR) assay based on SYBR Green I dye has not been established for BVDV detection. This study aims to develop a quantitative one-step RT-PCR assay to detect BVDV type-1 in cell culture.</p> <p>Results</p> <p>One-step quantitative SYBR Green I RT-PCR was developed by amplifying cDNA template from viral RNA and using <it>in vitro </it>transcribed BVDV RNA to establish a standard curve. The assay had a detection limit as low as 100 copies/ml of BVDV RNA, a reaction efficiency of 103.2%, a correlation coefficient (R<sup>2</sup>) of 0.995, and a maximum intra-assay CV of 2.63%. It was 10-fold more sensitive than conventional RT-PCR and can quantitatively detect BVDV RNA levels from 10-fold serial dilutions of titrated viruses containing a titer from 10<sup>-1 </sup>to 10<sup>-5 </sup>TCID<sub>50</sub>, without non-specific amplification. Melting curve analysis showed no primer-dimers and non-specific products.</p> <p>Conclusions</p> <p>The one-step SYBR Green I RT-PCR is specific, sensitive and reproducible for the quantification of BVDV in cell culture. This one-step SYBR Green I RT-PCR strategy may be further optimized as a reliable assay for diagnosing and monitoring BVDV infection in animals. It may also be applied to evaluate candidate agents against HCV using BVDV cell culture model.</p

    Coordinated voltage control for improved power system voltage stability by incorporating the reactive power reserve from wind farms

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    The absorption and output characteristics of reactive power of the doubly-fed induction generator (DFIG) greatly influence the voltage stability of PCC (Point of Common Coupling) where the wind farms are integrated into the bulk power grid. This study proposes a reactive power compensation strategy for coordinated voltage control (CVC) of PCC with large-scale wind farms to achieve the expected voltage quality of the power grid through a minimum amount of control actions in emergencies. To this end, the mechanism of reactive power and voltage control inside DFIG is first analyzed. Then, the concept of reactive power reserve (RPR) sensitivity concerning control actions is introduced and an index of voltage stability margin is proposed to evaluate and analyze the distance between the current operating point and the voltage collapse point by analyzing the relationship between reactive power reserve and voltage stability margin. In the event of an emergency, critical reactive power reserves are obtained to reduce the dimension and complexity of the control problem. The sensitivity of reactive power reserve and the control are formulated into a convex quadratic programming problem to optimize the control strategies for voltage stability. The proposed technology has been validated on the IEEE 39-bus system

    Modified Biogeography-Based Optimization with Local Search Mechanism

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    Biogeography-based optimization (BBO) is a new effective population optimization algorithm based on the biogeography theory with inherently insufficient exploration capability. To address this limitation, we proposed a modified BBO with local search mechanism (denoted as MLBBO). In MLBBO, a modified migration operator is integrated into BBO, which can adopt more information from other habitats, to enhance the exploration ability. Then, a local search mechanism is used in BBO to supplement with modified migration operator. Extensive experimental tests are conducted on 27 benchmark functions to show the effectiveness of the proposed algorithm. The simulation results have been compared with original BBO, DE, improved BBO algorithms, and other evolutionary algorithms. Finally, the performance of the modified migration operator and local search mechanism are also discussed

    Effect of a Management Algorithm for Wet Contamination of Peritoneal Dialysis System on the Prevention of Peritonitis: A Prospective Observational Study

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    Introduction: Wet contamination was a common problem of peritoneal dialysis (PD) system. We developed a management algorithm for wet contamination of PD system (wet contamination) on the basis of the related research literature and clinical practice experience. The purpose of this study was to observe clinical effect of the management algorithm on the prevention of peritonitis. Methods: Patients treated wet contamination in a single PD center between October 2017 and September 2022 were included. A management algorithm was established to treat wet contamination. It comprised identification of the contamination type, addressing contaminated or aging catheters, prophylactic antibiotics, and retraining. Demographic data and clinical data about wet contamination were collected and compared. Results: One hundred and forty-one cases of wet contamination were included in this study. The mean age was 51.7 Ā± 14.1 years, and 49.6% were female. The proportion of diabetic nephropathy was 9.9%. The median PD duration was 27.0 (1.7ā€“79.7) months. Eighteen episodes (12.8%) of wet contamination-associated peritonitis developed after wet contamination. The main pathogenic bacteria of peritonitis were Gram-positive bacteria (33.3%) and Gram-negative bacteria (27.8%). The incidence of wet contamination-associated peritonitis in the compliance with the management algorithm group was significantly lower than that in the non-compliance with the management algorithm group (0.9 vs. 48.6%; p &lt; 0.001). Non-compliance with management algorithm (OR = 185.861, p &lt; 0.001) together with advance age (OR = 1.116, p &lt; 0.001) and longer distance from home to hospital (OR = 1.007, p &lt; 0.001) were independent risk factors for wet contamination-associated peritonitis. Conclusion: The management algorithm for wet contamination of PD system could reduce the risk of peritonitis
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