An integrated approach to understanding the impact of network resonances and control on dynamic responses in VSC-HVdc networks

Postprint (published version

Impedance-Based Modelling of Hybrid AC/DC Grids With Synchronous Generator for Interaction Study and Dynamic Improvement

Hybrid AC/DC grids are increasingly been seen as the most important network structure for future transmission infrastructures. An emerging challenge to such grids is the constant interaction between various components in the system. Interactions could occur in many intricate forms including between and within the AC and DC subnetworks. However, considering the complexities involved, methods for detection that are intuitive, compact, and relatively straightforward to apply are lacking. In this paper, device-level closed-loop impedance models of subsystems in a hybrid AC/DC grid are extended compactly to subnetwork equivalents in the form of matrices. Then, interaction analysis between a voltage source converter (VSC) interconnected on both sides, and a synchronous generator with excitation control is carried out as a case study to highlight potentially detrimental interactions. The analysis is carried out in the frequency domain and validated with a nonlinear time domain simulations in MATLAB/SIMULINK.Peer ReviewedPostprint (author's final draft

SEOM clinical guidelines for the treatment of renal cell carcinoma

The purpose of this article was to provide updated recommendations for the diagnosis and treatment of renal cell carcinoma. Pathological confirmation is mandatory before treatment with ablative or focal therapies before any type of systemic therapy. Renal cell cancer should be staged according to the TNM classification system. A laparoscopic nephron-sparing surgery should be the approach for tumors <4 cm if technically feasible. Otherwise, radical (or partial in selected cases) nephrectomy is the treatment of choice, with lymph node dissection only performed in patients with clinically detected lymph node involvement. Some retrospective evidence for a cytoreductive nephrectomy in the postimmunotherapy era suggests a benefit in patients with good or intermediate risk or for patients with a symptomatic primary lesion. Adjuvant treatment with chemotherapy or with targeted agents is not recommended and studies are ongoing today. Patients with metastatic disease should be staged by computed tomography scans of the chest, abdomen and pelvis. The efficacy of sunitinib, bevacizumab plus interferon-α, and pazopanib is well established in patients with good and intermediate risk as well for temsirolimus in poor-risk patients. These four agents are considered standard of care in first-line treatment. Sorafenib, axitinib and everolimus are standard of care in second line in different settings based on their benefit in PFS. Besides some benefit described for IL-2 in highly selected patients in first line, there is a promising and emerging role for the new immunotherapeutic approaches in metastatic renal cell carcinoma

Primary and secondary power control of multiterminal HVDC grids

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Impedance modelling and parametric sensitivity of a VSC-HVDC system: New insights on resonances and interactions

Pervasiveness of power converters in the electric power system is expected in the future. Such large penetration will change the current power system dynamics leading to uncertain, unexpected, and potentially critical responses. This paper investigates the stability and resonance of a VSC-HVDC (Voltage Source Converter High Voltage Direct Current) link within an AC grid, whilst providing insights into resonances having a role on the grid. This is studied through the impedance-based modelling of the entire system (AC and DC grids), including controls of converters. Additionally, the impact of the different parameters of the hybrid AC-DC power system such as control systems and grid components on the system dynamics and stability is investigated. From this study, the impact of the system components and the controls of the converter on overall resonance response and stability is shown, including potential undesired sub-synchronous and harmonic resonances due to AC-DC system interactions. The analytical impedance-based models developed and obtained is validated through time-domain simulations, the physical model of the whole system is built in Simscape™ Power Systems™ and control systems in MATLAB/Simulink® (R2017b). This has demonstrated the validity of the model to deal with and detect such dynamics. © 2018 by the authors. Licensee MDPI, Basel, Switzerland.Peer ReviewedPostprint (published version

Un estudio comparativo de los instrumentos de medición de la calidad de los servicios públicos

En este trabajo se hace un repaso conceptual a la discusión existente en torno a los instrumentos de medición de la calidad de un servicio, prestando especial atención a la medición de la calidad de los servicios públicos. En esta revisión destaca el debate que se ha producido en la literatura alrededor de qué instrumento es mejor para medir la calidad: el SERVQUAL o el SERVPERF. A continuación se presenta un trabajo empírico sobre 888 individuos repartidos en tres muestras de usuarios de servicios públicos hospitalarios, universitarios y ferroviarios. En dicho estudio se compara la fiabilidad y validez de estos los dos instrumentos de medición de la calidad.This paper presents a conceptual overview of the discussion on existing instruments measuring quality of service, with special attention to measuring the quality of public services . This review highlights the debate that has occurred in the literature about which instrument is best to measure quality: SERVQUAL or SERVPERF. Then an empirical study on 888 individuals divided into three samples of hospital users, academics and public rail services is presented. In this study the reliability and validity of these two instruments measuring quality are compared

A phase II trial of gemcitabine plus carboplatin in advanced transitional cell carcinoma of the urothelium

<p>Abstract</p> <p>Background</p> <p>Recent studies have demonstrated the effectiveness of cisplatin-based combinations in patients with advanced transitional cell carcinoma(TCC) of the urothelium. Concern over cisplatin toxicity instigated a search for alternative regimens. The aim of the study was to evaluate the activity and tolerability of gemcitabine plus carboplatin combination as first-line treatment in patients with advanced transitional cell carcinoma of the urothelium.</p> <p>Methods</p> <p>Patients with advanced TCC were treated with gemcitabine 1200 mg/m²on days 1 and 8 and carboplatin area under the concentration-time curve(AUC) 5 on day 1 every 21 days.</p> <p>Results</p> <p>Out of 41 patients, thirty-nine were evaluable for efficacy and 41 for toxicity. A median of 5 cycles (range 1–6) was administered. Overall response rate was 46.2% (95% confidence interval: 32–65%) including 10.3% complete responses and 35.9% partial responses. The median time to progression and median overall survival were 7.5 months (95% confidence interval: 6.6–8.4 months) and 13.6 months (95% confidence interval: 10.2–17.0 months), respectively. Grade 3/4 neutropenia, anemia and thrombocytopenia were observed in 36.6%, 26.8, and 24.4% of patients, respectively. Non-hematological toxicity was generally mild. Grade 3 vomiting occurred in 1 (2.4%) patients.</p> <p>Conclusion</p> <p>The gemcitabine plus carboplatin combination is active in advanced TCC with acceptable toxicity and needs to be evaluated further and compared with other non-cisplatin-containing regimens.</p> <p>Trial registration</p> <p>ISRCTN88259320</p

Impact of converter losses on the optimal power flow solution of hybrid networks based on VSC-MTDC

This paper studies the impact of voltage source converter (VSC) losses on the solution of the optimal power flow (OPF) of hybrid AC/DC systems with a multi-terminal configuration. The motivation of this analysis is that the expected development of high voltage direct current (HVDC) systems will entail an increase of the number of converter stations, and consequently, converter losses might not be negligible when compared with conventional transmission losses of AC and DC lines. Towards this end, an extended OPF model is proposed considering a combination of VSC based multi-terminal HVDC grids (VSC-MTDC) and AC systems. The OPF model represents converter losses according to the state-of-the art modeling where different expressions are used when the converter functions as an inverter or as a rectifier. Three simpler alternative approaches are also implemented and the obtained OPF solutions are assessed. In order to compare the OPF solutions, a comparison metric is proposed. Obtained results show that modeling the converter losses in a simplified way could lead to very different power flow solutions, especially for the DC branches.Postprint (author's final draft

Involvement of extracellular vesicles in the macrophage-tumor cell communication in head and neck squamous cell carcinoma

Background Exosomes are cell-derived vesicles that mediate cellular communication in health and multiple diseases, including cancer. However, its role in head and neck cancer has been poorly defined. Here, we investigated the relevance of exosomes in the signaling between larynx cancer cells and macrophages. Methods Exosomes from THP1 macrophages and BICR18 cells (a larynx squamous cell carcinoma cell line) were purified and their role in the cancer cell migration, macrophage phenotype and immunosuppressive activity was evaluated. The activation of STAT3 signal transduction in macrophages in response to exosomes obtained from cancer cells was also evaluated. Results Macrophages foster the cancer cell migration and this effect is mediated by exosome signaling. On the other hand, exosomes also induce the expression of IL-10 in macrophages and PD-L1 in cancer cells, thus resulting in the promotion of an immunosuppressive environment. Moreover, we observed that the effects induced in cancer cells are mediated by the exosome-depending activation of STAT-3 signal transduction pathway. Conclusions Our study indicates that exosomes released by both macrophages and cancer cells plays a critical role in tumor progression in larynx cancer and might be a potential target for therapeutic intervention in head and neck cancer

The impact of prior platinum therapy on survival in patients with metastatic urothelial cancer receiving vinflunine

Background: A phase III trial demonstrated an overall survival advantage with the addition of vinflunine to best supportive care (BSC) in platinum-refractory advanced urothelial cancer. We subsequently examined the impact of an additional 2 years of survival follow-up and evaluated the influence of first-line platinum therapy on survival. Methods: The 357 eligible patients from the phase III study were categorised into two cohorts depending on prior cisplatin treatment: cisplatin or non-cisplatin. Survival was calculated using the Kaplan–Meier method. Results: The majority had received prior cisplatin (70.3%). Survival was higher in the cisplatin group (HR: 0.76; CI 95% 0.58–0.99; P=0.04) irrespective of treatment arm. Multivariate analysis including known prognostic factors (liver involvement, haemoglobin, performance status) and prior platinum administration did not show an independent effect of cisplatin. Vinflunine reduced the risk of death by 24% in the cisplatin-group (HR: 0.76; CI 95% 0.58–0.99; P=0.04) and by 35% in non-cisplatin patients (HR: 0.65; CI 95% 0.41–1.04; P=0.07). Interpretation: Differences in prognostic factors between patients who can receive prior cisplatin and those who cannot may explain the survival differences in patients who undergo second line therapy. Prior cisplatin administration did not diminish the subsequent benefit of vinflunine over BSC