This article addresses the problem of optimizing voltage profiles in distribution networks. The voltage optimization is split into two stages; the former is performed offline and the latter online. ...First, the network is partitioned into several weakly coupled voltage control zones (VCZs) with pilot nodes (PNs). Then, the partitioning is used to optimize the voltage profiles of the distribution systems on the frame of a two time-scale-based coordinated approach. At the first level, a centralized voltage optimization problem (VOP), minimizing the distance of bus voltages at the PNs from their reference values and subject to linearized power flow equations, is solved to fix the positions of the on-load tap changer and of step-voltage regulators, and the reactive powers provided by capacitor banks. At the second level, the VOP is implemented according to a decentralized approach, in which the solution is obtained by applying a distributed algorithm based on the alternating direction method of multipliers. It optimizes in each VCZ the voltage at the PN by acting on the active and reactive powers provided by the distributed energy resources present in the VCZ; the VCZ solutions are driven to the global optimum of the whole distribution system by a limited data exchange between the PNs. The proposed approach reduces the complexity and computational burden typical when solving the VOP on a large scale system. The proposed strategy is tested on the modified IEEE 123-bus system; various load and generation scenarios are analyzed proving the effectiveness of the proposed approach in achieving the objective of voltage regulation.
Ovarian clear cell adenocarcinoma (OCCA) is an uncommon histotype that is generally refractory to platinum-based chemotherapy. We analyze here the most comprehensive gene expression and copy number ...data sets, to date, to identify potential therapeutic targets of OCCA.
Gene expression and DNA copy number were carried out using primary human OCCA tumor samples, and findings were confirmed by immunohistochemistry on tissue microarrays. Circulating interleukin (IL) 6 levels were measured in serum from patients with OCCA or high-grade serous cancers and related to progression-free and overall survival. Two patients were treated with sunitinib, and their therapeutic responses were measured clinically and by positron emission tomography.
We find specific overexpression of the IL6-STAT3-HIF (interleukin 6-signal transducer and activator of transcription 3-hypoxia induced factor) pathway in OCCA tumors compared with high-grade serous cancers. Expression of PTHLH and high levels of circulating IL6 in OCCA patients may explain the frequent occurrence of hypercalcemia of malignancy and thromboembolic events in OCCA. We describe amplification of several receptor tyrosine kinases, most notably MET, suggesting other potential therapeutic targets. We report sustained clinical and functional imaging responses in two OCCA patients with chemotherapy-resistant disease who were treated with sunitinib, thus showing significant parallels with renal clear cell cancer.
Our findings highlight important therapeutic targets in OCCA, suggest that more extensive clinical trials with sunitinib in OCCA are warranted, and provide significant impetus to the growing realization that OCCA is molecularly and clinically distinct to other forms of ovarian cancer.
A key issue in Low Voltage(LV) distribution systems is to identify strategies for the optimal management and control in the presence of Distributed Energy Resources (DERs). To reduce the number of ...variables to be monitored and controlled, virtual levels of aggregation, called Virtual Microgrids (VMs), are introduced and identified by using new models of the distribution system. To this aim, this paper, revisiting and improving the approach outlined in a conference paper, presents a sensitivity-based model of an LV distribution system, supplied by a Medium/Low Voltage (MV/LV) substation and composed by several feeders, which is suitable for the optimal management and control of the grid and for VM definition. The main features of the proposed method are: it evaluates the sensitivity coefficients in a closed form; it provides an overview of the sensitivity of the network to the variations of each DER connected to the grid; and it presents a limited computational burden. A comparison of the proposed method with both the exact load flow solutions and a perturb-and-observe method is discussed in a case study. Finally, the method is used to evaluate the impact of the DERs on the nodal voltages of the network.
This paper deals with the problem of the voltage profile optimization in a distribution system including distributed energy resources. Adopting a centralized approach, the voltage optimization is a ...non-linear programming problem with large number of variables requiring a continuous remote monitoring and data transmission from/to loads and distributed energy resources. In this study, a recently-proposed Jacobian-based linear method is used to model the steady-state operation of the distribution network and to divide the network into voltage control zones so as to reformulate the centralized optimization as a quadratic programming of reduced dimension. New clustering methods for the voltage control zone definition are proposed to consider the dependence of the nodal voltages on both active and reactive powers. Zoning methodologies are firstly tested on a 24-nodes low voltage network and, then, applied to the voltage optimization problem with the aim of analyzing the impact of the R/X ratios on the zone evaluation and on the voltage optimization solution.
Abstract Objective To assess whether inflammatory markers predict atherosclerotic disease activity after carotid treatment in patients with severe carotid stenosis and nonsignificant coronary artery ...disease undergoing carotid stenting. Patients and Methods From March 1, 2004, to September 30, 2005, a total of 55 consecutive patients (mean ± SD age, 69±8.3 years; 26 men) with severe carotid stenosis and nonsignificant coronary artery disease were treated with carotid stent implantation. Patients were followed up for a period of 5 years for the occurrence of cardiovascular events. Results A significant correlation between quantitative analysis of debris entrapped in the filters and inflammatory markers was found. Moreover, the number of particles per filter, the total particles area, and the mean particle axis per filter were significantly higher in patients with clinical events at the follow-up compared with patients without events (87 vs 32, P =.006; 50,118.7 vs 17,782, P =.002; 33.9 vs 30.2, P =.03). At 5-year follow-up we recorded cardiovascular or neurologic events in 11 of the 55 patients (20%). Higher preprocedural levels of high-sensitivity C-reactive protein, interleukin 6 soluble receptor, and interleukin 6 were significantly associated with clinical events at follow-up ( P <.001, P =.05, and P =.02, respectively). In particular high-sensitivity C-reactive protein measured at 24 and 48 hours after carotid stenting showed a significant correlation with clinical events ( P =.001). Also preprocedural intracellular adhesion molecule 1 and circulating vascular cell adhesion molecule 1 blood concentrations were significantly correlated with a worse prognosis at follow-up ( P =.04 and P =.03, respectively). Conclusion In patients with severe carotid stenosis and nonsignificant coronary artery disease, inflammation is associated with atherosclerotic disease activity and a worse prognosis. Interleukin 6, interleukin 6 soluble receptor, intracellular adhesion molecule 1, vascular cell adhesion molecule 1, and high-sensitivity C-reactive protein levels at baseline and 24 and 48 hours after carotid stenting are predictive of neurologic and cardiovascular events at follow-up.
This paper addresses the problem of optimizing the voltage profile of radially-operated distribution systems by acting on the active and reactive powers provided by distributed energy resources ...(DERs). A novel voltage optimization procedure is proposed by adopting a decentralized control strategy. To this aim, a centralized voltage optimization problem (VOP), minimizing the distance of all the nodal voltages from their reference values, is firstly formulated as a strictly-convex quadratic program. Then, the centralized VOP is rewritten by partitioning the network into voltage control zones (VCZs) with pilot nodes. To overcome the lack of strictly convexity determined by the reduction to the pilot nodes, the dual centralized VOP working on the augmented Lagrangian function is reformulated and iteratively solved by the method of multipliers. Finally, a fully-distributed VOP solution is obtained by applying a distributed algorithm based on the auxiliary problem principle, which allows for solving in each VCZ a quadratic programming problem of small dimension and to drive the VCZ solutions toward the overall optimum by an iterative coordination process that requires to exchange among the VCZs only scalar values. The effectiveness and feasibility of the proposed method have been demonstrated via numerical tests on the IEEE 123-bus system.
To determine if time to diagnosis is associated with stage of disease at diagnosis or survival among women with symptomatic ovarian cancer.
A representative sample of Australian women (n = 1,463) ...with ovarian cancer diagnosed between 2002 and 2005 who participated in a population-based case-control study were interviewed regarding the events leading to their diagnosis and were observed for mortality for 5 years.
Of the 1,318 women (90%) who presented to a medical practitioner with symptoms, 55% presented within 1 month, 70% in less than 2 months, and 92% within 6 months of symptom onset. There were no significant differences in the time from symptom onset to first medical practitioner consultation (P = .19) or symptom onset to diagnosis (P = .64) among women with borderline, early (International Federation of Gynecology and Obstetrics FIGO stages I to II) or late (FIGO stages III to IV) disease. There was also no association between time to diagnosis and survival; adjusted hazard ratio for long delay (> 12 months from symptom onset to diagnosis) versus short delay (≤ 1 month) was 0.94 (95% CI, 0.68 to 1.30). Women who had asymptomatic cancers diagnosed incidentally (n = 145) were younger and were more likely to have borderline or stage I disease compared with women who had symptomatic ovarian cancer.
The results of this study suggest that, once ovarian cancer is symptomatic, reducing the time to diagnosis would not greatly alter stage of disease at diagnosis or survival.
Most industrial trucks are equipped with hydraulic systems designed for specific operations, for which the required power is supplied by the internal combustion engine (ICE). The largest share of the ...power consumption is required by the hydraulic system during idling operations, and, consequently, the current literature focuses on energy saving strategies for the hydraulic system rather than making the vehicle traction more efficient. This study presents the preliminary realization of an electric-powered hydraulic pump system (e-HPS) that drives the lifting of the dumpster and the garbage compaction in a waste compactor truck, rather than traditional ICE-driven hydraulic pump systems (ICE-HPSs). The different components of the e-HPS are described and the battery pack was modelled using the kinetic battery model. The end-of-life of the battery pack was determined to assess the economic feasibility of the proposed e-HPS for the truck lifespan, using numerical simulations. The aim was twofold: to provide an implementation method to retrofit the e-HPS to a conventional waste compactor truck and to assess its economic feasibility, investigating fuel savings during the use phase and the consequent reduction of CO2 emissions. Results show that the total lifespan cost saving achieved a value of 65,000 €. Furthermore, total CO2 emissions for the e-HPS were about 80% lower than those of the ICE-HPS, highlighting that the e-HPS can provide significant environmental benefits in an urban context.
Most women with ovarian cancer have a poor prognosis, but studies have reported an association between statin use and improved survival. We investigated the potential survival benefit of statins in ...women with ovarian cancer using data from the Ovarian cancer Prognosis and Lifestyle study, a prospective study of Australian women aged 18 to 79 years, diagnosed with ovarian cancer from 2012 to 2015 and followed for 5 to 8 years. We obtained information from patient‐completed questionnaires and medical records. We defined exposure based on prediagnosis use, as most women used statins continuously (prediagnosis and postdiagnosis) and few started using statins postdiagnosis. We measured survival from date of first treatment (surgery or neoadjuvant chemotherapy) until date of death or last follow‐up. We used Cox regression to calculate hazard ratios (HR) and 95% confidence intervals (CI), adjusting for potential confounders. To reduce bias due to confounding by indication, we also applied inverse probability of treatment weighting (IPTW). Of 955 eligible women, 21% reported statin use before diagnosis. Statin users had a slightly better survival (HR = 0.90, 95% CI = 0.70‐1.15) that was driven by lipophilic statin use (HR = 0.82, 95% CI = 0.61‐1.11), with no association for hydrophilic statins (HR = 1.04, 95% CI = 0.72‐1.49). The IPTW model weighted to all women with ovarian cancer also suggested a possible reduction in mortality associated with lipophilic statins (HR = 0.80, 95% CI = 0.54‐1.21). In analyses restricted to women with hyperlipidaemia, the HRs were further from the null. Our findings are consistent with previous evidence, suggesting that lipophilic statins might improve ovarian cancer survival. Further investigation, in larger cohorts, or preferably in a randomised trial, is required.
What's new?
Ovarian cancer generally has a poor prognosis. Some previous studies have indicated that statins may improve survival, but these may have been subject to various forms of bias. In the present study, the authors used statistical methods that minimize bias to analyze data from a prospective Australian trial. They found that lipophilic statins may indeed enhance survival for ovarian cancer patients, particularly for women with hyperlipidaemia. Hydrophilic statins had no effect on survival. Further investigations to evaluate lipophilic statins in larger cohorts, preferably randomized clinical trials, are recommended.
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