82 research outputs found

    A systematic review of DC wind farm collector cost-effectiveness

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    DC collection systems have been suggested to improve the cost-effectiveness of offshore wind farms but no consensus currently exists on which configurations are the most promising. This paper aims to determine the primary DC wind farm candidates for commercialisation based on cost-effectiveness and technological risk. A systematic review was performed of the literature that formally assesses the cost, losses or reliability of DC wind farm configurations. The optimal configurations were found to be dependent on the methodology and assumptions used by each study, as well as the individual wind farm characteristics. Series and series-parallel DC designs without offshore platform performed well in terms of costs, but have challenges in operation and reliability that limit the short-term opportunity for commercialisation. The standard DC parallel topology has the lowest technological risk, but the mean cost reported in the literature is similar to that of AC topologies. Standard parallel DC wind farms are the primary candidate for the first commercial DC wind farm demonstrators, but the optimal design will likely need to be determined on a case-by-case basis. Guidelines for this assessment are provided

    Frequency optimisation for DC/DC converters in DC-connected offshore wind turbines

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    In all-DC wind farms, DC/DC converters connect the low voltage wind turbine output to the high voltage DC array. One potential benefit of using DC/DC converters is that they require a relatively small transformer due to their higher frequency operation. However, there is no consensus as to what this frequency should be. This paper aims to determine the optimal operating frequency for DC/DC converters in 15 MW wind turbines connected to an 80 kV DC array. A multi-objective optimisation is performed taking into account the DC/DC converter volume, weight and losses. Frequencies ranging from 500 Hz to 5 kHz were tested for unidirectional, bidirectional, single-phase and three-phase converters. The optimal frequencies for unidirectional and bidirectional converters were found to be approximately 2 kHz and 1 kHz, respectively

    Review and comparison of single and dual active bridge converters for MVDC-connected wind turbines

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    A key component for all-DC wind farms is the DC/DC converter. The converter must have multi-megawatt power capability, a high step-up ratio, provide galvanic isolation, and operate efficiently while being able to fit in the wind turbine nacelle. The single active bridge (SAB) and dual active bridge (DAB) converters in standalone or cascaded configuration are promising topologies that have the potential to meet these requirements. This paper reviews the operation and control of these converters, and compares their volume, weight, and efficiency for a 15 MW wind turbine with 80 kV DC connection. The results show that the standalone topologies are significantly smaller and lighter than their cascaded counterparts. However, all topologies fit inside the wind turbine nacelle. The SAB designs are the most efficient and robust, as they use diodes in the output bridge. The DAB topologies have the advantage of bidirectional power flow at the cost of additional switches and losses. The standalone DAB requires series-connected switches in the output bridge, which may difficult to implement. The cascaded topologies offer higher reliability without significantly increasing losses, making them the most attractive option for future DC wind turbines

    Review of MVDC applications, technologies, and future prospects

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    This paper presents a complete review of MVDC applications and their required technologies. Four main MVDC applications were investigated: rail, shipboard systems, distribution grids, and offshore collection systems. For each application, the voltage and power levels, grid structures, converter topologies, and protection and control structure were reviewed. Case studies of the varying applications as well as the literature were analyzed to ascertain the common trends and to review suggested future topologies. For rail, ship, and distribution systems, the technology and ability to implement MVDC grids is available, and there are already a number of case studies. Offshore wind collection systems, however, are yet able to be implemented. Across the four applications, the MVDC voltages ranged from 5–50 kV DC and tens of MW, with some papers suggesting an upper limit of 100 kV DC and hundreds of MV for distribution networks and offshore wind farm applications. This enables the use of varying technologies at both the lower and high voltage ranges, giving flexibility in the choice of topology that is required required

    Pan-Cancer Analysis of lncRNA Regulation Supports Their Targeting of Cancer Genes in Each Tumor Context

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    Long noncoding RNAs (lncRNAs) are commonly dys-regulated in tumors, but only a handful are known toplay pathophysiological roles in cancer. We inferredlncRNAs that dysregulate cancer pathways, onco-genes, and tumor suppressors (cancer genes) bymodeling their effects on the activity of transcriptionfactors, RNA-binding proteins, and microRNAs in5,185 TCGA tumors and 1,019 ENCODE assays.Our predictions included hundreds of candidateonco- and tumor-suppressor lncRNAs (cancerlncRNAs) whose somatic alterations account for thedysregulation of dozens of cancer genes and path-ways in each of 14 tumor contexts. To demonstrateproof of concept, we showed that perturbations tar-geting OIP5-AS1 (an inferred tumor suppressor) andTUG1 and WT1-AS (inferred onco-lncRNAs) dysre-gulated cancer genes and altered proliferation ofbreast and gynecologic cancer cells. Our analysis in-dicates that, although most lncRNAs are dysregu-lated in a tumor-specific manner, some, includingOIP5-AS1, TUG1, NEAT1, MEG3, and TSIX, synergis-tically dysregulate cancer pathways in multiple tumorcontexts

    Pan-cancer Alterations of the MYC Oncogene and Its Proximal Network across the Cancer Genome Atlas

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    Although theMYConcogene has been implicated incancer, a systematic assessment of alterations ofMYC, related transcription factors, and co-regulatoryproteins, forming the proximal MYC network (PMN),across human cancers is lacking. Using computa-tional approaches, we define genomic and proteo-mic features associated with MYC and the PMNacross the 33 cancers of The Cancer Genome Atlas.Pan-cancer, 28% of all samples had at least one ofthe MYC paralogs amplified. In contrast, the MYCantagonists MGA and MNT were the most frequentlymutated or deleted members, proposing a roleas tumor suppressors.MYCalterations were mutu-ally exclusive withPIK3CA,PTEN,APC,orBRAFalterations, suggesting that MYC is a distinct onco-genic driver. Expression analysis revealed MYC-associated pathways in tumor subtypes, such asimmune response and growth factor signaling; chro-matin, translation, and DNA replication/repair wereconserved pan-cancer. This analysis reveals insightsinto MYC biology and is a reference for biomarkersand therapeutics for cancers with alterations ofMYC or the PMN

    Genomic, Pathway Network, and Immunologic Features Distinguishing Squamous Carcinomas

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    This integrated, multiplatform PanCancer Atlas study co-mapped and identified distinguishing molecular features of squamous cell carcinomas (SCCs) from five sites associated with smokin

    Spatial Organization and Molecular Correlation of Tumor-Infiltrating Lymphocytes Using Deep Learning on Pathology Images

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    Beyond sample curation and basic pathologic characterization, the digitized H&E-stained images of TCGA samples remain underutilized. To highlight this resource, we present mappings of tumorinfiltrating lymphocytes (TILs) based on H&E images from 13 TCGA tumor types. These TIL maps are derived through computational staining using a convolutional neural network trained to classify patches of images. Affinity propagation revealed local spatial structure in TIL patterns and correlation with overall survival. TIL map structural patterns were grouped using standard histopathological parameters. These patterns are enriched in particular T cell subpopulations derived from molecular measures. TIL densities and spatial structure were differentially enriched among tumor types, immune subtypes, and tumor molecular subtypes, implying that spatial infiltrate state could reflect particular tumor cell aberration states. Obtaining spatial lymphocytic patterns linked to the rich genomic characterization of TCGA samples demonstrates one use for the TCGA image archives with insights into the tumor-immune microenvironment

    Extended Coagulation Profiling in Isolated Traumatic Brain Injury:A CENTER-TBI Analysis

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    Background: Trauma-induced coagulopathy in traumatic brain injury (TBI) remains associated with high rates of complications, unfavorable outcomes, and mortality. The underlying mechanisms are largely unknown. Embedded in the prospective multinational Collaborative European Neurotrauma Effectiveness Research in Traumatic Brain Injury (CENTER-TBI) study, coagulation profiles beyond standard conventional coagulation assays were assessed in patients with isolated TBI within the very early hours of injury. Methods: Results from blood samples (citrate/EDTA) obtained on hospital admission were matched with clinical and routine laboratory data of patients with TBI captured in the CENTER-TBI central database. To minimize confounding factors, patients with strictly isolated TBI (iTBI) (n = 88) were selected and stratified for coagulopathy by routine international normalized ratio (INR): (1) INR &lt; 1.2 and (2) INR ≄ 1.2. An INR &gt; 1.2 has been well adopted over time as a threshold to define trauma-related coagulopathy in general trauma populations. The following parameters were evaluated: quick’s value, activated partial thromboplastin time, fibrinogen, thrombin time, antithrombin, coagulation factor activity of factors V, VIII, IX, and XIII, protein C and S, plasminogen, D-dimer, fibrinolysis-regulating parameters (thrombin activatable fibrinolysis inhibitor, plasminogen activator inhibitor 1, antiplasmin), thrombin generation, and fibrin monomers. Results: Patients with iTBI with INR ≄ 1.2 (n = 16) had a high incidence of progressive intracranial hemorrhage associated with increased mortality and unfavorable outcome compared with patients with INR &lt; 1.2 (n = 72). Activity of coagulation factors V, VIII, IX, and XIII dropped on average by 15–20% between the groups whereas protein C and S levels dropped by 20%. With an elevated INR, thrombin generation decreased, as reflected by lower peak height and endogenous thrombin potential (ETP), whereas the amount of fibrin monomers increased. Plasminogen activity significantly decreased from 89% in patients with INR &lt; 1.2 to 76% in patients with INR ≄ 1.2. Moreover, D-dimer levels significantly increased from a mean of 943 mg/L in patients with INR &lt; 1.2 to 1,301 mg/L in patients with INR ≄ 1.2. Conclusions: This more in-depth analysis beyond routine conventional coagulation assays suggests a counterbalanced regulation of coagulation and fibrinolysis in patients with iTBI with hemostatic abnormalities. We observed distinct patterns involving key pathways of the highly complex and dynamic coagulation system that offer windows of opportunity for further research. Whether the changes observed on factor levels may be relevant and explain the worse outcome or the more severe brain injuries by themselves remains speculative.</p

    Rehabilitation and outcomes after complicated vs uncomplicated mild TBI:results from the CENTER-TBI study

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    Background: Despite existing guidelines for managing mild traumatic brain injury (mTBI), evidence-based treatments are still scarce and large-scale studies on the provision and impact of specific rehabilitation services are needed. This study aimed to describe the provision of rehabilitation to patients after complicated and uncomplicated mTBI and investigate factors associated with functional outcome, symptom burden, and TBI-specific health-related quality of life (HRQOL) up to six months after injury. Methods: Patients (n = 1379) with mTBI from the Collaborative European NeuroTrauma Effectiveness Research in TBI (CENTER-TBI) study who reported whether they received rehabilitation services during the first six months post-injury and who participated in outcome assessments were included. Functional outcome was measured with the Glasgow Outcome Scale – Extended (GOSE), symptom burden with the Rivermead Post Concussion Symptoms Questionnaire (RPQ), and HRQOL with the Quality of Life after Brain Injury – Overall Scale (QOLIBRI-OS). We examined whether transition of care (TOC) pathways, receiving rehabilitation services, sociodemographic (incl. geographic), premorbid, and injury-related factors were associated with outcomes using regression models. For easy comparison, we estimated ordinal regression models for all outcomes where the scores were classified based on quantiles. Results: Overall, 43% of patients with complicated and 20% with uncomplicated mTBI reported receiving rehabilitation services, primarily in physical and cognitive domains. Patients with complicated mTBI had lower functional level, higher symptom burden, and lower HRQOL compared to uncomplicated mTBI. Rehabilitation services at three or six months and a higher number of TOC were associated with unfavorable outcomes in all models, in addition to pre-morbid psychiatric problems. Being male and having more than 13 years of education was associated with more favorable outcomes. Sustaining major trauma was associated with unfavorable GOSE outcome, whereas living in Southern and Eastern European regions was associated with lower HRQOL. Conclusions: Patients with complicated mTBI reported more unfavorable outcomes and received rehabilitation services more frequently. Receiving rehabilitation services and higher number of care transitions were indicators of injury severity and associated with unfavorable outcomes. The findings should be interpreted carefully and validated in future studies as we applied a novel analytic approach. Trial registration: ClinicalTrials.gov NCT02210221.</p
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