53 research outputs found

    Marginal cost-based pricing of distribution: a case study

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    This paper presents results of a software development project carried out by the “Electricity North West” (ENW) and “TNEI” to find economic use-of-system charges for the extra high-voltage (EHV) network. Several cost-based charging models which satisfy principles set by the Regulator, such as cost reflectivity, predictability, stability and transparency were developed. In this paper, the emphasis is put on the developed software and the comparison of nodal marginal charges obtained from the proposed pricing models

    Diabetic gastroparesis in association with autonomic neuropathy and microvasculopathy.

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    Gastroparesis is a frequent and sometimes life-threatening complication of diabetes mellitus. Autonomic neuropathy seems to be one of the most important mechanisms underlying this entity, together with the other probable pathologies. The present study was performed in order to identify an alternative to gastric scintigraphy as a screening test. The gastric emptying times of 60 subjects (Group 1: 20 insulin-dependent patients, Group 2: 20 non-insulin-dependent diabetes mellitus patients, and Group 3: 20 healthy volunteers) were monitored by gastric scintigraphy. Perception thresholds for cold, heat, and vibration were tested by a quantitative sensory test, and QTc dispersions were calculated from standard electrocardiography recordings. In addition, fasting blood glucose, hemoglobin A1c and urine beta2-microglobulin and microalbumin concentrations were determined for the patient groups. Funduscopic examination was performed by an independent ophthalmologist. Gastroparesis was determined in both patient groups, regardless of fasting blood glucose and hemoglobin A1c concentrations. A strong correlation was observed between nephropathy, retinopathy, and cardiac autonomic denervation (QTc) and gastroparesis. In conclusion, retinal and renal microvasculopathy parameters and cardiac autonomic function tests may be useful for screening diabetic patients for gastroparesis.</p

    Pay-as-bid pricing in combined pool / bilateral electricity markets

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    In the context of combined pool/bilateral operation of electricity markets, this paper compares two pricing strategies; pay-as-bid strategy defines three types of services: bilateral contract generation, transmission loss and congestion management required by the bilateral contracts, and pool demand generation including associated transmission loss and congestio

    Assessment of the last-in-first out principle of access for managing the connection of distributed wind generators

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    Recent projects in the UK have investigated different connection arrangements for managing distributed wind generators to maintain thermal limits and a number of principle of access for generators to the limited distribution network capacity have been investigated. However, principle of access to manage voltage limits have not received as much attention. This study aims to evaluate the current practice for connecting ‘non-firm’ distributed wind generators under both voltage and thermal constraint conditions. It addresses the issue by developing a representative model of a UK 11kV radial distribution feeder comprising a mix of urban and rural sections using time-step optimal power flow simulations. The results indicated that when the principle is applied under both network constraint conditions, it can lead to inefficient use of network capacities and reduced renewable energy yields

    Radioactive metals disposal and recycling impact modelling

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    Screening life cycle assessment models developed to investigate hypothetical disposal and recycling options for the Windscale Advanced Gas-cooled Reactor heat exchangers were used to generate more complex models addressing the main UK radioactive metals inventory. Both studies show there are significant environmental advantages in the metals recycling promoted by the current low level waste disposal policies, strategies and plans. Financial benefits from current metals treatment options are supported and offer even greater benefits when applied to the UK radioactive metals inventory as a whole

    Distributed negotiation in future power networks : rapid prototyping using multi-agent system

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    Technologies like multi-agent system (MAS) have the capability to deal with future power grid requirements such as frequency management and voltage control under a flexible, intelligent and active feature. Based on web of cells (WoC) architecture proposed by European Liaison on Electricity Committed Towards longer-term Research Activity Integrated Research Programme (ELECTRA IRP), a distributed MAS with distributed negotiation ability for future distributed control (including frequency management and voltage control) is proposed. Each cell is designed as an intelligent agent and is investigated in case studies with constraints, where each agent can only communicate with its neighbouring agents. The interaction logic among agents is according to the distributed negotiation algorithm under consideration by the authors. Simulation results indicate that the WoC architecture could negotiate resources in a distributed manner and achieve successful exchange of resources by coordinating distributed agents. Moreover, the prototype reported in this paper can be extended further for future grids' distributed control regimes. The option of MAS to be exploited for the support of the development and integration of novel power system concepts is explored

    Protein Kinase Cδ Stimulates Proteasome-Dependent Degradation of C/EBPα during Apoptosis Induction of Leukemic Cells

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    BACKGROUND:The precise regulation and maintenance of balance between cell proliferation, differentiation and death in metazoan are critical for tissue homeostasis. CCAAT/enhancer-binding protein alpha (C/EBPalpha) has been implicated as a key regulator of differentiation and proliferation in various cell types. Here we investigated the potential dynamic change and role of C/EBPalpha protein during apoptosis induction. METHODOLOGY/PRINCIPAL FINDINGS:Upon onset of apoptosis induced by various kinds of inducers such as NSC606985, etoposide and others, C/EBPalpha expression presented a profound down-regulation in leukemic cell lines and primary cells via induction of protein degradation and inhibition of transcription, as assessed respectively by cycloheximide inhibition test, real-time quantitative RT-PCR and luciferase reporter assay. Applying chemical inhibition, forced expression of dominant negative mutant and catalytic fragment (CF) of protein kinase Cdelta (PKCdelta), which was proteolytically activated during apoptosis induction tested, we showed that the active PKCdelta protein contributed to the increased degradation of C/EBPalpha protein. Three specific proteasome inhibitors antagonized C/EBPalpha degradation during apoptosis induction. More importantly, ectopic expression of PKCdelta-CF stimulated the ubiquitination of C/EBPalpha protein, while the chemical inhibition of PKCdelta action significantly inhibited the enhanced ubiquitination of C/EBPalpha protein under NSC606985 treatment. Additionally, silencing of C/EBPalpha expression by small interfering RNAs enhanced, while inducible expression of C/EBPalpha inhibited NSC606985/etoposide-induced apoptosis in leukemic cells. CONCLUSIONS/SIGNIFICANCE:These observations indicate that the activation of PKCdelta upon apoptosis results in the increased proteasome-dependent degradation of C/EBPalpha, which partially contributes to PKCdelta-mediated apoptosis

    Optical Imaging of Tumor Response to Hyperbaric Oxygen Treatment and Irradiation in an Orthotopic Mouse Model of Head and Neck Squamous Cell Carcinoma

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    PURPOSE: Hyperbaric oxygen therapy (HBOT) is used in the treatment of radiation-induced tissue injury but its effect on (residual) tumor tissue is indistinct and therefore investigated in this study. PROCEDURES: Orthotopic FaDu tumors were established in mice, and the response of the (irradiated) tumors to HBOT was monitored by bioluminescence imaging. Near infrared fluorescence imaging using AngioSense750 and Hypoxisense680 was applied to detect tumor vascular permeability and hypoxia. RESULTS: HBOT treatment resulted in accelerated growth of non-irradiated tumors, but mouse survival was improved. Tumor vascular leakiness and hypoxia were enhanced after HBOT, whereas histological characteristics, epithelial-to-mesenchymal transition markers, and metastatic incidence were not influenced. CONCLUSIONS: Squamous cell carcinoma responds to HBOT with respect to tumor growth, vascular permeability, and hypoxia, which may have implications for its use in cancer patients. The ability to longitudinally analyze tumor characteristics highlights the versatility and potential of optical imaging methods in oncological research. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s11307-015-0834-8) contains supplementary material, which is available to authorized users

    European union perspective on kyoto protocol : emissions trading scheme and renewable resources

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    Athough a climate on our planet has been changing for a millions of years, recent shifts in world-wide weather patterns are more dramatic than expected. These changes have motivated research communities and grassroots movements to re-evaluate how we behave towards the environment, and to re-examine whether our life-style may cause severe imbalances in the atmosphere, which eventually may endanger or even extinguish many species on our planet. From the perspective of electric power utilization, there are a number of ways in which both generation and demand side can contribute towards an alleviation of the environmental problems. For example, one way would be to reduce emissions of pollutants and greenhouse gases from power stations into the atmosphere, while the other option is to increase the amount of electricity coming from renewable resources. In addition, improving energy efficiency will reduce the amount of energy that is wasted, and therefore lower energy demand. The focus of this presentation is on the European Union (EU) practices regarding emissions and trading of greenhouse gases, and on efforts to promote and ensure employment of renewable resources

    Unit commitment for combined pool/bilateral markets with emissions trading

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    The paper proposes a unit commitment problem formulation which models combined pool/bilateral operation as well as effects of emissions constraints and emissions trading mechanisms. In here proposed model, power outputs of generators are, on one hand, bounded by their bilateral contract commitments, and on the other side, by the amount of CO2 emissions that they are allowed to produce over time. These emissions constraints introduce additional complexity as it is becoming more important for generating units to decide on when and how much to produce, as well as to investigate how to mange their allocated CO2 permissions in the most economic way. Since the proposed formulation of the market clearing includes costs of buying and selling of CO2 allowances, it permits analysis on how emission caps and emission market prices can influence generation decisions and the resulting generation scheduling. The method is illustrated on a 5-unit system, and given examples investigate how different levels of bilateral trades, as well as amounts of CO2 allowances, may affect the market outcome
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