120 research outputs found

    An Advanced Control and Extensible Configuration for Static Var Generator

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    An extensible configuration is proposed for static var generator (SVG) with advanced controller included for reactive power compensation of grid. Compared with the traditional configurations, the major advantage of such system configuration is that the power modules are very flexible and easy to extend or reduce without changing the main equipment of SVG under the different voltage levels. Furthermore, in order to solve the problems of modeling uncertainty, nonlinearities, and outside disturbance by using proportion integration (PI) controller, an advanced controller is proposed based on auto disturbance rejection control (ADRC). By controlling the amount and direction of reactive current, the reactive power is generated or absorbed from SVG into power grid with fast response, which can realize the excellent dynamic compensation for both the internal and external interferences. Simulations results show that the proposed controller has better performance of the transient and steady state than PI controller. Moreover, the verification tests are executed in 380 V, 6.5 kVA experiment systems, suggesting that the excellent dynamic performance and strong robustness are achieved

    Cancer Nanotechnology: Enhancing Tumor Cell Response to Chemotherapy for Hepatocellular Carcinoma Therapy

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    Abstract Hepatocellular carcinoma (HCC) is one of the deadliest cancers due to its complexities, reoccurrence after surgical resection, metastasis and heterogeneity. In addition to sorafenib and lenvatinib for the treatment of HCC approved by FDA, various strategies including transarterial chemoembolization, radiotherapy, locoregional therapy and chemotherapy have been investigated in clinics. Recently, cancer nanotechnology has got great attention for the treatment of various cancers including HCC. Both passive and active targetings are progressing at a steady rate. Herein, we describe the lessons learned from pathogenesis of HCC and the understanding of targeted and non-targeted nanoparticles used for the delivery of small molecules, monoclonal antibodies, miRNAs and peptides. Exploring current efficacy is to enhance tumor cell response of chemotherapy. It highlights the opportunities and challenges faced by nanotechnologies in contemporary hepatocellular carcinoma therapy, where personalized medicine is increasingly becoming the mainstay. Overall objective of this review is to enhance our understanding in the design and development of nanotechnology for treatment of HCC

    Combined laparoscopy and hysteroscopy vs. uterine curettage in the uterine artery embolization-based management of cesarean scar pregnancy: a retrospective cohort study

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    BACKGROUND: The number of cesarean scar pregnancy (CSP) has significantly increased in the recent decade. Although uterine artery embolization (UAE) has been adopted to minimize the blood loss during uterine curettage removing of CSP, massive bleeding and uterine rupture can still be frequently encountered. The aim of this study was to compare the efficacy and safety of a novel combined laparoscopy and hysteroscopy technique with the traditional curettage in removing the conceptus and repairing the incision defect following the UAE management of CSP. METHODS: The CSP patients (n = 58) diagnosed between March 1, 2005 and March 1, 2010 were enrolled in three medical centers in Shanghai, China. All of these patients have undergone intra-arterial methotrexate, UAE and one of the following treatments: combined laparoscopy and hysteroscopy (study group, n = 25) and uterine curettage (control group, n = 33). Their medical records and 2-year outcomes were reviewed. The CSP removal rate, amount of blood loss during the treatment, incision repair rate (note: the post-curettage healing process of the incision defect was seen as a form of natural incision repairing, i.e., the self-repair mode), hospital stay, Ξ²-hCG regression time and postoperative sequelae were compared between two groups. RESULTS: The CSP removal rate in the study group (100%) was significantly higher than that (79%) in the control group (p = 0.024). The average blood loss was 78.0Β mL in the study group, which was much less than the 258.5Β mL (p = 0.004) in the control group. A satisfactory incision repair rate (96%) was achieved in the study group, while it was 25% (p < 0.001) in the control group. Moreover, the study group had significantly shorter hospital stays (p = 0.043) and Ξ²-hCG regression times (p = 0.033), lower rates of postoperative abdominal pain (p = 0.035) and menstruation abnormalities (p = 0.043). CONCLUSIONS: Combined laparoscopy and hysteroscopy is much safer and more effective than uterine curettage as a supplementary measure to remove the conceptus and repair the cesarean incision following the UAE management of CSP

    Insufficient Radiofrequency Ablation Promotes Angiogenesis of Residual Hepatocellular Carcinoma Via HIF-1Ξ±/VEGFA

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    Background: The mechanism of rapid growth of the residual tumor after radiofrequency (RF) ablation is poorly understood. In this study, we investigated the effect of hyperthermia on HepG2 cells and generated a subline with enhanced viability and dys-regulated angiogenesis in vivo, which was used as a model to further determine the molecular mechanism of the rapid growth of residual HCC after RF ablation. Methodology/Principal Findings: Heat treatment was used to establish sublines of HepG2 cells. A subline (HepG2 k) with a relatively higher viability and significant heat tolerance was selected. The cellular protein levels of VEGFA, HIF-1Ξ± and p-Akt, VEGFA mRNA and secreted VEGFA were measured, and all of these were up-regulated in this subline compared to parental HepG2 cells. HIF-1Ξ± inhibitor YC-1 and VEGFA siRNA inhibited the high viability of the subline. The conditioned media from the subline exerted stronger pro-angiogenic effects. Bevacizumab, VEGFA siRNA and YC-1 inhibited proangiogenic effects of the conditioned media of HepG2 k cells and abolished the difference between parental HepG2 cells and HepG2 k cells. For in vivo studies, a nude mouse model was used, and the efficacy of bavacizumab was determined. HepG2 k tumor had stronger pro-angiogenic effects than parental HepG2 tumor. Bevacizumab could inhibit the tumor growth and angiogenesis, and also eliminate the difference in tumor growth and angiogenesis between parental HepG2 tumor and HepG2 k tumor in vivo. Conclusions/Significance: The angiogenesis induced by HIF1Ξ±/VEGFA produced by altered cells after hyperthermia treatment may play an important role in the rapid growth of residual HCC after RF ablation. Bevacizumab may be a good candidate drug for preventing and treating the process

    Self-powered on-line ion concentration monitor in water transportation driven by triboelectric nanogenerator

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    The final publication is available at Elsevier via https://doi.org/10.1016/j.nanoen.2019.05.029. Β© 2019. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/Ion concentration in water is a key criterion for evaluating water quality. In this work, we developed a self-powered on-line ion concentration monitor in water transportation based on impedance matching effect of triboelectric nanogenerator (TENG). A rotary disc-shaped TENG (RD-TENG) and an ion concentration sensor were fabricated based on the industrial printed circuit board (PCB) technology. Flowing water in the pipeline acts as the energy source to drive the RD-TENG and generate an open-circuit (Voc) of 210β€―V. The ion concentration sensor exhibits a nearly pure resistance characteristic under the alternating current (AC) signal with the frequency below 500β€―Hz, corresponding to the rotation speed of 250β€―rpm for the RD-TENG. The impedance matching relationship between the RD-TENG and the ion concentration sensor was experimentally studied and applied to elucidate the sensing mechanism. Finally, a self-powered sensing system integrated with an alarm circuit was assembled which exhibits excellent responsibility and high sensitivity. The change of ion concentration with only 1β€―Γ—β€―10βˆ’5β€―mol/L can light up an alarm LED.Natural Science and Engineering Research CouncilCanada Research ChairsNational Natural Science Foundation of China, no. 61804103National Key R&D Program of China, no. 2017YFA0205002Natural Science Foundation of the Jiangsu Higher Education Institutions of China, no. 18KJA535001, no. 14KJB150020Natural Science Foundation of Jiangsu Province of China, no. BK20170343, no. BK20180242China Postdoctoral Science Foundation, no. 2017M610346Collaborative Innovation Center of Suzhou Nano Science & TechnologyPriority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)111 Projec

    ASXL1 interacts with the cohesin complex to maintain chromatid separation and gene expression for normal hematopoiesis

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    ASXL1 is frequently mutated in a spectrum of myeloid malignancies with poor prognosis. Loss of Asxl1 leads to myelodysplastic syndrome-like disease in mice; however, the underlying molecular mechanisms remain unclear. We report that ASXL1 interacts with the cohesin complex, which has been shown to guide sister chromatid segregation and regulate gene expression. Loss of Asxl1 impairs the cohesin function, as reflected by an impaired telophase chromatid disjunction in hematopoietic cells. Chromatin immunoprecipitation followed by DNA sequencing data revealed that ASXL1, RAD21, and SMC1A share 93% of genomic binding sites at promoter regions in Lin-cKit+ (LK) cells. We have shown that loss of Asxl1 reduces the genome binding of RAD21 and SMC1A and alters the expression of ASXL1/cohesin target genes in LK cells. Our study underscores the ASXL1-cohesin interaction as a novel means to maintain normal sister chromatid separation and regulate gene expression in hematopoietic cells

    Coordinated Translocation of Mammalian Gli Proteins and Suppressor of Fused to the Primary Cilium

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    Intracellular transduction of Hedgehog (Hh) signals in mammals requires functional primary cilia. The Hh signaling effectors, the Gli family of transcription factors, and their negative regulator, Suppressor of Fused (Sufu), accumulate at the tips of cilia; however, the molecular mechanism regulating this localization remains elusive. In the current study, we show that the ciliary localization of mammalian Gli proteins depends on both their N-terminal domains and a central region lying C-terminal to the zinc-finger DNA-binding domains. Invertebrate Gli homologs Ci and Tra1, when over-expressed in ciliated mouse fibroblasts, fail to localize to the cilia, suggesting the lack of a vertebrate-specific structural feature required for ciliary localization. We further show that activation of protein kinase A (PKA) efficiently inhibits ciliary localization of Gli2 and Gli3, but only moderately affects the ciliary localization of Gli1. Interestingly, variants of Gli2 mimicking the phosphorylated or non-phosphorylated states of Gli2 are both localized to the cilia, and their ciliary localizations are subjected to the inhibitory effect of PKA activation, suggesting a likely indirect mechanism underlying the roles of PKA in Gli ciliary localization. Finally, we show that ciliary localization of Sufu is dependent on ciliary-localized Gli proteins, and is inhibited by PKA activation, suggesting a coordinated mechanism for the ciliary translocation of Sufu and Gli proteins
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