50 research outputs found
Association of Helicobacter pylori with colorectal cancer development.
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
Optimization of fractional PI controller parameters for enhanced induction motor speed control via indirect field-oriented control
Introduction. Induction Motors (IM) possess advantages such as stability, reliability, and ease of control, making them suitable for many purposes; the literature elucidates control methodologies for IM drives, primarily focusing on scalar and vector control techniques; the conventional method utilized in manufacturing is scalar control, which unfortunately demonstrates optimal performance solely in steady-state conditions. The absence of significant instantaneous torque control restricts flux and dissociated torque, resulting in subpar dynamic responsiveness. Indirect Field Oriented Control (IFOC) for IM drives has proven beneficial for various industrial applications, particularly electric vehicle propulsion. The primary advantages of this approach include the decoupling of torque and flux characteristics and its straightforward implementation. The novelty of the work consists of a proposal for a driving cycle model for testing the control system of electric vehicles in Mosul City (Iraq), and using a Complex Fractional Order Proportional Integral (CFOPI) controller to control IMs via IFOC strategies, the Artificial Bee Colony (ABC) algorithm was applied, which is considered to be highly efficient in finding the values of controllers. Purpose. Improvement IFOC techniques for the regulation of IM speed. Methods. Using the ABC algorithm in tuning the two unique CFOPI controller, and a Real Fractional Order Proportional Integral (RFOPI) controller, to regulate the speed of a three-phase IM via IFOC techniques. Results. The CFOPI controller outperforms the RFOPI controller in obtaining the best performance in controlling the IM. Practical value. The CFOPI controller demonstrates superiority over the RFOPI controller, as evidenced by the lower integral time absolute error in motor speed tracking during the driving cycle 2.1004 for the CFOPI controller compared to 2.1538 for the RFOPI controller. References 27, tables 5, figures 4.Вступ. Асинхронні двигуни (АД) мають такі переваги, як стабільність, надійність і легкість керування, що робить їх придатними для багатьох цілей; література пояснює методології керування приводами АД, головним чином зосереджуючись на методах скалярного та векторного керування; звичайний метод, який використовується у виробництві, – це скалярне керування, яке, на жаль, демонструє оптимальну продуктивність лише в стаціонарних умовах. Відсутність значного миттєвого контролю крутного моменту обмежує потік і дисоційований крутний момент, що призводить до низької динамічної чутливості. Непряме поле-орієнтоване керування (IFOC) для приводів АД, довело свою користь для різноманітних промислових застосувань, зокрема для двигунів електромобілів. Основні переваги цього підходу включають відокремлення характеристик крутного моменту та потоку та його пряме впровадження. Новизна роботи полягає в пропозиції моделі циклу водіння для тестування системи керування електромобілями в місті Мосул (Ірак), і використання контролера комплексного дробового порядку пропорційного інтегралу (CFOPI) для керування АД за допомогою стратегій IFOC, було застосовано алгоритм штучної бджолиної колонії (ABC), який вважається високоефективним у пошуку значень контролерів. Мета. Удосконалення методики IFOC для регулювання швидкості АД. Методи. Використання алгоритму ABC для налаштування двох унікальних контролерів CFOPI та контролера реального дробового порядку пропорційного інтегралу (RFOPI) для регулювання швидкості трифазного АД за допомогою методів IFOC. Результати. Контролер CFOPI перевершує контролер RFOPI в отриманні найкращої продуктивності в управлінні АД. Практична цінність. Контролер CFOPI демонструє перевагу над контролером RFOPI, про що свідчить менша абсолютна похибка інтегрального часу у відстеженні швидкості двигуна під час циклу руху 2.1004 для контролера CFOPI порівняно з 2.1538 для контролера RFOPI. Бібл. 27, табл. 5, рис. 4
A new approach to detecting and classifying multiple faults in IEEE 14-bus system
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
Implementation of a standardized protocol to manage elderly patients with low energy pelvic fractures: can service improvement be expected?
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
Comparison of multiple modulation techniques for various topologies of multilevel converters for single phase AC motor drive
There are various types of Multilevel Converters (MCs) in addition to various types of modulation techniques for these types of MCs; the challenges in selecting the best one of them with regard to the amount of the required of components, and its harmonics content. So, a comparison study among these types has been done in this paper. For comparison study, the simulation of seven level of two popular topologies of MCs: Neutral Point Clamped (NPC) converter, and Cascaded-MCs were carried out with Matlab/Simulink software program. These converters are used to drive a single phase capacitor start motor drive. Multicarrier modulation control techniques are used for controlling the MCs; these techniques involve two main type: Level Shifted Carrier (LSC), and Phase Shifted Carrier (PSC). The comparison is made with respect to the performance factors as, the amplitude of the Total Harmonic Distortion (THD), and the DC-bus utilization performance which measured by Root Mean Square of the output voltage Vrms at variable modulation indices and variable carrier frequency. Based on simulation results it's found, that the cascaded-MC with PSC modulation method gives best results, in addition to the Alternative Phase Opposition Disposition APOD-LSC modulation technique (with even number of modulation frequency) generate the output voltage with a lower harmonic content compared with the other techniques
Brushless DC motor drive with optimal fractional-order sliding-mode control based on a genetic algorithm
Introduction. Brushless DC (BLDC) motor is a type of permanent magnet synchronous motor that operates without brushes employed in many applications owing to its efficiency and control in electric cars. One of the main reasons BLDC motors are better than brushed DC motors is that they employ an electronic commutation circuit instead of a mechanical one. The fractional order sliding mode controller (FOSMC) was used, which is characterized by high durability and is not affected by the disturbances that the motor is exposed to during operation, as well as overcoming the chattering phenomenon present in the conventional sliding mode controller (CSMC). The novelty of the proposed work consists of to use FOSMC by genetic algorithm (GA) to mitigate the chattering phenomena in sliding mode control (SMC) for optimal response for speed control and regeneration braking control in BLDC motor by using single stage by voltage source inverter and decrease energy use during motor starting. Purpose. Improvement FOSMC techniques for the regulation of BLDC motor’s driving control system. Methods. Employing the GA to optimize the parameters of FOSMC to mitigate the chattering phenomenon in SMC to regulate BLDC motor’s driving control system. Results. A comparison was made between two types of sliding controllers to obtain the best performance of the control system in speed control operations and motor braking operations, the FOSMC, through parameter optimization via the GA, surpasses the CSMC in achieving optimal performance in driving the BLDC motor. Practical value. FOSMC exhibits superiority over the CSMC, as indicated by the reduced integral time absolute error in motor speed tracking and regenerative brake control, with values of (0.028, 0.046, and 0.075) for the FOSMC, in contrast to (2.72, 1.56, and 0.17) for the CSMC, the overshoot for FOSMC is (0, 0, and 11.4), but for CSMC it is (60.4, 43.7, and 11.2). During braking mode for FOSMC, the power recovery from the motor to the battery was (1.96, 9, and 17.76), but in CSMC, it was (0.99, 4.49, and 11.98). Moreover, the braking length was expedited, and the battery’s initial power consumption diminished at the outset. References 32, tables 5, figures 6
Reductions in readmission rates are associated with modest improvements in patient-reported health gains following hip and knee replacement in England
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
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
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
