91 research outputs found

    DEVELOPING BUSSINESS AND USER MEASUREMENT OF THE SYSTEM AVAILABILITY

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    This work presents basic elements of availability measurement methodology in complex technical systems according to business and users aspect. Methodology, which is primarily related to IT1 systems, is applied to and presented as a case study of Information system of Tax administration - DIS 2003. To achieve designed objectives of implemented methodology, it is necessary to provide "common" measurement from two different aspects: technical and business. The measurement result is system availability level as well as clear identification of critical components that influence the IT infrastructure stability and assure service continuity provided by the system

    Impact of Short-Term Variations in the Generation Output of Geographically Dispersed PV Systems

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    When viewed in hourly intervals, a solar photovoltaic (PV) system appears to have a more stable output than usual. However, there are short-term rapid variations in its generation output that result from transient cloudiness and weather disturbances in the atmosphere. By using Monte Carlo simulations applied to a Markov model, this study demonstrates the short-term intermittency of the transient weather conditions and estimates the generation of geographically dispersed PV systems with a capacity of ten percent of peak demand of a statewide grid in one-minute intervals. This study found that geographically distributed PV systems evaluated in one-minute intervals could cope with peaks of a statewide power grid because of the smoothing effect caused by the geographical spread. The purpose of the exercise is to create a framework for integration and optimization of multiple generation sources in order to meet the uncertainty of the fast changing PV output under certain weather conditions.

    Radiation Therapy in Extensive Stage Small Cell Lung Cancer.

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    Lung cancer is the major cancer killer in the Western world, with the small cell lung cancer (SCLC) representing around 15-20% of all lung cancers. Extensive disease small cell lung cancer (ED SCLC) is found in approximately two-thirds of all cases, composed of both metastatic (M1) and non-metastatic (but presumably with tumor burden too large for locoregional-only approach) variant. Standard treatment options involve chemotherapy (CHT) over the past several decades. Radiation therapy (RT) had mostly been used in palliation of locoregional and/or metastatic disease. In contrast to its established role in treating metastatic disease, thoracic RT (TRT) had never been established as important part of the treatment aspects in this setting. In the past two decades, thoracic oncologists have witnessed wide introduction of modern RT and CHT aspects in ED SCLC, which led to more frequent use of RT and rise in the number of clinical studies. Since the pivotal study of Jeremic et al., who were the first to show importance of TRT in ED SCLC, a number of single-institutional studies have reconfirmed this observation, while recent prospective randomized trials (CREST and RTOG 0937) brought more substance to this issue. Similarly, the issue of prophylactic cranial irradiation was investigated in EORTC and the Japanese study, respectively, bringing somewhat conflicting results and calling for additional research in this setting. Future studies in ED SCLC could incorporate questions of RT dose and fractionation as well as the number of CHT cycles and type of combined Rt-CHT (sequential vs concurrent)

    an analysis of the ClinicalTrials.gov database

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    Background To evaluate the current status of prospective interventional clinical trials that includes brachytherapy (BT) procedures. Methods The records of 175,538 (100 %) clinical trials registered at ClinicalTrials.gov were downloaded on September 2014 and a database was established. Trials using BT as an intervention were identified for further analyses. The selected trials were manually categorized according to indication(s), BT source, applied dose rate, primary sponsor type, location, protocol initiator and funding source. We analyzed trials across 8 available trial protocol elements registered within the database. Results In total 245 clinical trials were identified, 147 with BT as primary investigated treatment modality and 98 that included BT as an optional treatment component or as part of the standard treatment. Academic centers were the most frequent protocol initiators in trials where BT was the primary investigational treatment modality (p < 0.01). High dose rate (HDR) BT was the most frequently investigated type of BT dose rate (46.3 %) followed by low dose rate (LDR) (42.0 %). Prostate was the most frequently investigated tumor entity in trials with BT as the primary treatment modality (40.1 %) followed by breast cancer (17.0 %). BT was rarely the primary investigated treatment modality for cervical cancer (6.8 %). Conclusion Most clinical trials using BT are predominantly in early phases, investigator-initiated and with low accrual numbers. Current investigational activities that include BT mainly focus on prostate and breast cancers. Important questions concerning the optimal usage of BT will not be answered in the near future

    Portfolio of prospective clinical trials including brachytherapy: an analysis of the ClinicalTrials.gov database

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    Background: To evaluate the current status of prospective interventional clinical trials that includes brachytherapy (BT) procedures. Methods: The records of 175,538 (100 %) clinical trials registered at ClinicalTrials.gov were downloaded on September 2014 and a database was established. Trials using BT as an intervention were identified for further analyses. The selected trials were manually categorized according to indication(s), BT source, applied dose rate, primary sponsor type, location, protocol initiator and funding source. We analyzed trials across 8 available trial protocol elements registered within the database. Results: In total 245 clinical trials were identified, 147 with BT as primary investigated treatment modality and 98 that included BT as an optional treatment component or as part of the standard treatment. Academic centers were the most frequent protocol initiators in trials where BT was the primary investigational treatment modality (p<0.01). High dose rate (HDR) BT was the most frequently investigated type of BT dose rate (46.3 %) followed by low dose rate (LDR) (42.0 %). Prostate was the most frequently investigated tumor entity in trials with BT as the primary treatment modality (40.1 %) followed by breast cancer (17.0 %). BT was rarely the primary investigated treatment modality for cervical cancer (6.8 %). Conclusion: Most clinical trials using BT are predominantly in early phases, investigator-initiated and with low accrual numbers. Current investigational activities that include BT mainly focus on prostate and breast cancers. Important questions concerning the optimal usage of BT will not be answered in the near future

    HYPERLIPIDEMIA IN ACUTE PANCREATITIS: CONCOMITANT DISORDER OR A CAUSE?

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    Acute pancreatitis is a common condition with alcohol and gallstones being the most frequent etiologies. The aim of our study was to determine the prevalence of hyperlipidemia, its etiopathogenetic role and influence on outcomes in patients with acute pancreatitis.The study included 47 patients admitted to our clinic for acute pancreatitis during one year period. On admission patients with hyperlipidemia were compared to those without it, regarding following parameters: body mass index, Glasgow score, organ failure occurrence, local complications occurrence (pancreatic necrosis, pseudocyst, abscess, jaundice, gastric outlet syndrome), intensive care unit stay and death. The results of the study revealed high incidence of hyperlipidemia in 51% of examined acute pancreatitis patients with the prevalence of severe forms in more than half of these patients. Dominant lipid disorder was hypertriglyceridemia, followed by hypercholesterolemia. It was clearly demonstrated that patients with hyperlipidemia, especially hypertriglyceridemia, had more severe acute pancreatitis, higher incidence of complications and poorer outcome compared to normolipemic patients. Hyperlipidemia in patients with acute pancreatitis should be considered and treated by a clinician as a separate serious problem, both when being a cause and a concomitant disorder. Hypolipidemic therapy should be administered both in urgent acute pancreatitis settings and as a long-term treatment aimed to prevent inflammation recurrence by successful persistent serum lipid levels control.Key words: Hyperlipidemia, acute pancreatitis

    Current status and perspectives of interventional clinical trials for glioblastoma - analysis of ClinicalTrials.gov

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    The records of 208.777 (100%) clinical trials registered at ClinicalTrials.gov were downloaded on the 19th of February 2016. Phase II and III trials including patients with glioblastoma were selected for further classification and analysis. Based on the disease settings, trials were classified into three groups: newly diagnosed glioblastoma, recurrent disease and trials with no differentiation according to disease setting. Furthermore, we categorized trials according to the experimental interventions, the primary sponsor, the source of financial support and trial design elements. Trends were evaluated using the autoregressive integrated moving average model. Two hundred sixteen (0.1%) trials were selected for further analysis. Academic centers (investigator initiated trials) were recorded as primary sponsors in 56.9% of trials, followed by industry 25.9%. Industry was the leading source of monetary support for the selected trials in 44.4%, followed by 25% of trials with primarily academic financial support. The number of newly initiated trials between 2005 and 2015 shows a positive trend, mainly through an increase in phase II trials, whereas phase III trials show a negative trend. The vast majority of trials evaluate forms of different systemic treatments (91.2%). In total, one hundred different molecular entities or biologicals were identified. Of those, 60% were involving drugs specifically designed for central nervous system malignancies. Trials that specifically address radiotherapy, surgery, imaging and other therapeutic or diagnostic methods appear to be rare. Current research in glioblastoma is mainly driven or sponsored by industry, academic medical oncologists and neuro-oncologists, with the majority of trials evaluating forms of systemic therapies. Few trials reach phase III. Imaging, radiation therapy and surgical procedures are underrepresented in current trials portfolios. Optimization in research portfolio for glioblastoma is needed
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