34 research outputs found

    A new approach to detecting and classifying multiple faults in IEEE 14-bus system

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    Faults in the power system generally provide considerable changes in its quantities such as under or over-power, over-current, current or power direction, frequency, impedance, and power factor. Reading data related to both currents and voltages is usually involved for detecting and situating the fault on the transmission network. These days, any outage of power in a power grid leads to heavy financial losses for commercial, industrial, and domestic consumers. Random and irregular faults in transmission grids contribute significantly to events of power outages. A significant contribution of this study is a new technique for simulating a multiple simultaneous faults model. The recommended approach is an effective technique for detection, classification and localization of faults in transmission networks of electric power. To attain this objective, a training procedure and a neural network simulation were carried out using m-file in MATLAB. A virtual bus has been proposed to analyze the fault which happens on the transmission line and bus. This technique has been applied on the IEEE 14 bus and multiple simultaneous faults have been mentioned in this study. The fault situations are simulated in m-files through the two-port network performance method, which is a highly enhanced scheme in comparison to the existing methods. The results have been arrived upon by subjecting different buses to varying types of fault. The results provide comprehensive information regarding fault current, post-fault voltages, and fault MVA on all the buses. The values at the bus for voltage, power consumption, and phase angles were specified. As suggested by the findings of the simulation, the proposed methodology is an effective technique for detection, classification and localization of fault

    Association of Helicobacter pylori with colorectal cancer development.

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    Background: Helicobacter pylori (H. pylori) may be associated with colorectal cancer. However, the underlying mechanisms are still unclear. Objectives: Explore the serostatus of H. pylori cytotoxicity-associated gene A product (CagA) in patients with colorectal carcinoma, and assess the association of H. pylori with colorectal cancer via c-Myc and MUC-2 proteins at tumor tissues. Methods: H. pylori CagA IgG antibodies were screened using enzyme-linked immunosorbent assay (ELISA) in 30 patients with colorectal carcinoma and 30 cancer-free control subjects. Paraffin-embedded blocks were examined for the expression of c-Myc and MUC-2 protein by immunohistochemistry. Results: H. pylori CagA seropositivity increased significantly among colorectal cancer patients (p <0.05). The expression of c-Myc and MUC-2 in colorectal carcinoma patients was over-expressed (80%), and downexpressed (63%) in resection margins (p <0.05). c-Myc over-expression and MUC-2 down-expression were associated with CagA-positive rather than CagA-negative H. pylori patients. In 16 CagA seropositive vs. 14 CagA seronegative patients, the expression rate was 97.3% vs. 64.2% and 33.3% vs. 78.5% for cMyc and MUC-2, respectively. CagA IgG level was significantly higher in positive than in negative c-Myc patients (p= 0.036), and in negative than in positive MUC-2 patients (p= 0.044). c-Myc and MUC-2 were positively and inversely correlated with CagA IgG level (p <0.05). Conclusions: CagA-seropositive H. pylori is most probably associated with colorectal cancer development. Part of the underlying mechanism for such association might be via alterations in expression of MUC-2, which depletes the mucous protective layer in the colo-rectum, and c-Myc, which stimulates the growth of cancerous cells

    Implementation of a standardized protocol to manage elderly patients with low energy pelvic fractures: can service improvement be expected?

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    Purpose: The incidence of low energy pelvic fractures (FPFs) in the elderly is increasing. Comorbidities, decreased bone-quality, problematic fracture fixation and poor compliance represent some of their specific difficulties. In the absence of uniform management, a standard operating procedure (SOP) was introduced to our unit, aiming to improve the quality of services provided to these patients. Methods: A cohort study was contacted to test the impact of (1) using a specific clinical algorithm and (2) using different antiosteoporotic drugs. Multivariate regression analysis was used to determine prognostic factors. Study endpoints were the time-to-healing, length-of-stay, return to pre-injury mobility, union status, mortality and complications. Results: A total of 132 elderly patients (≥65 years) admitted during the period 2012–2014 with FPFs were enrolled. High-energy fractures, acetabular fractures, associated trauma affecting mobility, pathological pelvic lesions and operated FPFs were used as exclusion criteria. The majority of included patients were females (108/132; 81.8%), and the mean age was 85.8 years (range 67–108). Use of antiosteoporotics was associated with a shorter time of healing (p = 0.036). Patients treated according to the algorithm showed a significant protection against malunion (p < 0.001). Also, adherence to the algorithm allowed more patients to return to their pre-injury mobility status (p = 0.039). Conclusions: The use of antiosteoporotic medication in elderly patients with fragility pelvic fractures was associated with faster healing, whilst the adherence to a structured clinical pathway led to less malunions and non-unions and return to pre-injury mobility state

    Reductions in readmission rates are associated with modest improvements in patient-reported health gains following hip and knee replacement in England

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    Background: Although many hospital readmission reduction initiatives have been introduced globally, health care systems ultimately aim to improve patients' health and well-being. We examined whether the hospitals that report greater success in reducing readmissions also see greater improvements in patient-reported outcomes. Research Design: We examined hospital groups (Trusts) that provided hip replacement or knee replacement surgery in England between April 2010 and February 2013. For each Trust, we calculated risk-Adjusted 30-day readmission rates from administrative datasets. We also obtained changes in patient-reported health between presurgical assessment and 6-month follow-up, using general health EuroQuol five dimensions questionaire (EQ-5D) and EuroQuol visual analogue scales (EQ-VAS) and procedure-specific (Oxford Hip and Knee Scores) measures. Panel models were used to assess whether changes over time in risk-Adjusted readmission rates were associated with changes over time in risk-Adjusted health gains. Results: Each percentage point reduction in the risk-Adjusted readmission rate for hip replacement was associated with an additional health gain of 0.004 for EQ-5D [95% confidence interval (CI), 0.002-0.006], 0.39 for EQ-VAS (95% CI, 0.26-0.52), and 0.32 for Oxford Hip Score (95% CI, 0.15-0.27). Corresponding figures for knee replacement were 0.003 for EQ-5D (95% CI, 0.001-0.004), 0.21 for EQ-VAS (95% CI, 0.12-0.30), and 0.14 in the Oxford Knee Score (95% CI, 0.09-0.20). Conclusions: Reductions in readmission rates were associated with modest improvements in patients' sense of their health and well-being at the hospital group level. In particular, fears that efforts to reduce readmission rates have had unintended consequences for patients appear to be unfounded

    A realist analysis of hospital patient safety in Wales:Applied learning for alternative contexts from a multisite case study

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    Background: Hospital patient safety is a major social problem. In the UK, policy responses focus on the introduction of improvement programmes that seek to implement evidence-based clinical practices using the Model for Improvement, Plan-Do-Study-Act cycle. Empirical evidence that the outcomes of such programmes vary across hospitals demonstrates that the context of their implementation matters. However, the relationships between features of context and the implementation of safety programmes are both undertheorised and poorly understood in empirical terms. Objectives: This study is designed to address gaps in conceptual, methodological and empirical knowledge about the influence of context on the local implementation of patient safety programmes. Design: We used concepts from critical realism and institutional analysis to conduct a qualitative comparative-intensive case study involving 21 hospitals across all seven Welsh health boards. We focused on the local implementation of three focal interventions from the 1000 Lives+ patient safety programme: Improving Leadership for Quality Improvement, Reducing Surgical Complications and Reducing Health-care Associated Infection. Our main sources of data were 160 semistructured interviews, observation and 1700 health policy and organisational documents. These data were analysed using the realist approaches of abstraction, abduction and retroduction. Setting: Welsh Government and NHS Wales. Participants: Interviews were conducted with 160 participants including government policy leads, health managers and professionals, partner agencies with strategic oversight of patient safety, advocacy groups and academics with expertise in patient safety. Main outcome measures: Identification of the contextual factors pertinent to the local implementation of the 1000 Lives+ patient safety programme in Welsh NHS hospitals. Results: An innovative conceptual framework harnessing realist social theory and institutional theory was produced to address challenges identified within previous applications of realist inquiry in patient safety research. This involved the development and use of an explanatory intervention–context–mechanism–agency–outcome (I-CMAO) configuration to illustrate the processes behind implementation of a change programme. Our findings, illustrated by multiple nested I-CMAO configurations, show how local implementation of patient safety interventions are impacted and modified by particular aspects of context: specifically, isomorphism, by which an intervention becomes adapted to the environment in which it is implemented; institutional logics, the beliefs and values underpinning the intervention and its source, and their perceived legitimacy among different groups of health-care professionals; and the relational structure and power dynamics of the functional group, that is, those tasked with implementing the initiative. This dynamic interplay shapes and guides actions leading to the normalisation or the rejection of the patient safety programme. Conclusions: Heightened awareness of the influence of context on the local implementation of patient safety programmes is required to inform the design of such interventions and to ensure their effective implementation and operationalisation in the day-to-day practice of health-care teams. Future work is required to elaborate our conceptual model and findings in similar settings where different interventions are introduced, and in different settings where similar innovations are implemented. Funding: The National Institute for Health Research Health Services and Delivery Research programme

    Combined pubic rami and sacral osteoporotic fractures: a prospective study

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    Background - Pelvic osteoporotic fractures (POFs) are often associated with considerable morbidity and mortality mainly as a result of infections and cardiovascular events. Patients usually need prolonged institutionalization, rehabilitation, and follow-up, with a high rate of dependency and cost. The most common sites of POFs include the pubic rami, sacrum, ilium, and acetabulum. Combined pubic rami (PROFs) and sacral osteoporotic fractures (SOFs) have been reported, mostly in retrospective studies, describing the mechanism of injury and incidence. The aim of this study was to evaluate the association between PROFs and SOFs and to assess the effect of combined PROFs and SOFs on patients’ mobility, discharge destination, and length of stay. Materials and methods - We prospectively studied 67 patients with low-impact PROFs and/or SOFs. There were 54 (80.4%) female and 13 (19.6%) male patients, and the average age was 87.5 (range 65–96) years. All patients were assessed by the fracture liaison service. Patients had magnetic resonance imaging or bone scan when there was history of low back pain following the injury or lumbosacral tenderness on clinical examination. Results - The mean length of stay for all patients was 45 (±35) days. Mortality rate was 10.4%. A significant relationship was found between low back pain and a positive finding of sacral fracture. Patients with combined PROFs and SOFs showed significantly longer length of stay than those with isolated PROFs. Conclusions - The presence of low back pain and tenderness in patients who had low-impact pelvic injuries was highly suggestive of the presence of an associated SOF. There was a high association between sacral and PROFs. The length of stay of patients with PROFs associated with sacral osteoporotic fractures was significantly longer than that of patients with PROFs only. Therefore, we recommend considering the high association between SOFs and PROFs in planning the management and rehabilitation of patients with POFs

    Comparative Analysis of Various Multicarrier Modulation Techniques for Different Multilevel Converters

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    The applications of Multilevel Converter (MLC) are increased because of the huge demand for clean power; especially these types of converters are compatible with the renewable energy sources. In addition, these new types of converters have the capability of high voltage and high power operation. A Nine-level converter in three modes of implementation; Diode Clamped-MLC (DC-MLC), Capacitor Clamped-MLC (CC-MLC), and the Modular Structured-MLC (MS-MLC) are analyzed and simulated in this paper. Various types of Multicarrier Modulation Techniques (MMTs) (Level shifted (LS), and Phase shifted (PS)) are used for operating the proposed Nine level - MLCs. Matlab/Simulink environment is used for the simulation, extracting, and analysis the results. Finally, a comparison is made between the results for all topologies that are implemented regarding to the criteria of the output voltage waveforms harmonic distortion factor, No. of the necessitated power components, and the complexity of each circuit. Based on simulation results, the MS-MLC is finer as compared to the other types of MLCs. It also observed that the MLCs (with three types) using Phase Opposition Disposition (POD) technique is performed better in terms of getting greater fundamental output voltage and lower THD% as compared to the other techniques

    A New Approach to Detecting and Classifying Multiple Faults in IEEE 14-bus System

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    Faults in the power system generally provide considerable changes in its quantities such as under or over-power, over-current, current or power direction, frequency, impedance, and power factor. Reading data related to both currents and voltages is usually involved for detecting and situating the fault on the transmission network. These days, any outage of power in a power grid leads to heavy financial losses for commercial, industrial, and domestic consumers. Random and irregular faults in transmission grids contribute significantly to events of power outages. A significant contribution of this study is a new technique for simulating a multiple simultaneous faults model. The recommended approach is an effective technique for detection, classification and localization of faults in transmission networks of electric power. To attain this objective, a training procedure and a neural network simulation were carried out using m-file in MATLAB. A virtual bus has been proposed to analyze the fault which happens on the transmission line and bus. This technique has been applied on the IEEE 14 bus and multiple simultaneous faults have been mentioned in this study. The fault situations are simulated in m-files through the two-port network performance method, which is a highly enhanced scheme in comparison to the existing methods. The results have been arrived upon by subjecting different buses to varying types of fault. The results provide comprehensive information regarding fault current, post-fault voltages, and fault MVA on all the buses. The values at the bus for voltage, power consumption, and phase angles were specified. As suggested by the findings of the simulation, the proposed methodology is an effective technique for detection, classification and localization of fault

    Combined pubic rami and sacral osteoporotic fractures: A prospective study of 67 patients

    No full text
    Introduction Pelvic osteoporotic fractures (POFs) are often associated with considerable morbidity and mortality, in addition to prolonged rehabilitation and high costs. The most common sites of POFs include the pubic rami and the sacrum. Combined pubic rami and sacral osteoporotic fractures (SOFs) have been reported previously with varying comments on the mechanism of injury and incidence. Purpose of the study To evaluate the mobility, discharge destination, presence of back pain and length of stay of patients who sustained combined pubic rami and SOFs and to identify the significance of this association. Methods We prospectively studied 67 patients with low-impact pubic rami and/or SOFs over 12 months. The patients were over 60 years of age and were assessed by the fracture liaison service. MR imaging or bone scan were done when there was back pain or lumbo-sacral tenderness. Results There were 54 (80.4%) female and 13 (19.6%) male patients and the average age was 87.5 years (range 65–96). The mean length of stay was 45 (±35) days. Mortality rate was 10.4%. There was a significant relationship between low back pain and the presence of sacral fracture. Patients with combined pubic rami and SOFs showed significantly longer length of stay than those with isolated pubic rami fractures. Conclusion We recommend considering the high association between SOFs and pubic rami fractures and the presence of back pain in planning the management of patients with POFs and their rehabilitation, which would potentially exhaust resources, due to their significantly increased length of stay and reduced mobility
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