437 research outputs found

    Online efficiency optimization of IPMSM for electric vehicles

    Get PDF
    This paper presents an online efficiency optimization method for the interior permanent magnet synchronous motor (IPMSM) drive system in an electric vehicle (EV). The proposed method considers accurately the total system losses including fundamental copper and iron losses, harmonic copper and iron losses, magnet loss, and inverter losses. Therefore, it has the capability to always guarantee maximum efficiency control. A highly trusted machine model is built using finite element analysis (FEA). This model considers accurately the magnetic saturation, spatial harmonics, and iron loss effect. The overall system efficiency is estimated online based on the accurate determination of system loss, and then the optimum current angle is defined online for the maximum efficiency per ampere (MEPA) control. A series of results is conducted to show the effectiveness and fidelity of proposed method. The results show the superior performance of proposed method over the conventional offline efficiency optimization methods

    Relation between single serum progesterone assay and viability of the first trimester pregnancy

    Get PDF
    This study was designed to detect the relation between serum progesterone and viability of pregnancy during the first trimester. Prospective study carried out in Al-Rashid Maternity and Ahmadi Kuwait oil company hospitals, over three years from February 2009 to February 2012. Two hundred and Sixty (260) pregnant women were hospitalized due to vaginal bleeding and/or abdominal pain during the first trimester of their pregnancies and were included in this study. Women included in this study were; sure of dates, conceived spontaneously with no history of infertility and had a positive serum pregnancy test. 2 ml blood samples were taken for women included in this study for serum progesterone assay. Women included in this study were followed by ultrasound for the viability of the pregnancy till the end of first trimester and the outcome of their pregnancy were recorded, while women with exogenous progesterone support or multiple pregnancies or suspected ectopic pregnancy or Hydatiform mole were excluded from this study. Data were collected and statistically analyzed to detect the relationship between serum progesterone level and viability of pregnancy during the first trimester. The mean age of the studied population was 32.7 ± 5.1 years, the mean gestational age at progesterone assay was 9.7 ± 0.5 week and by the end of the first trimester, women included in this study were classified according to the viability of their pregnancies into; viable pregnancy group 178 (68.5%) cases and non-viable pregnancy group (ended by miscarriage) 82 (31.5%) cases. The mean serum progesterone of the studied population was significantly high in viable pregnancy group (46.5 ± 7.4 ng/ml) compared to non-viable pregnancy group (9.9 ± 4.8 ng/ml), (p <0.05). In this study; 6.7% of viable pregnancies had serum progesterone level <10 ng/ ml, while 20.7% of non-viable pregnancies had serum progesterone level >10 ng/ml, the serum progesterone at cut off level 10 ng/ml was 79.3% sensitive to diagnose non-viable pregnancy and was 93.3% specific to diagnose viable pregnancy. Also, in this study; 1.1% of viable pregnancies had serum progesterone level <20 ng/ ml, while 4.8% of non-viable pregnancies had serum progesterone level >20 ng/ml, the serum progesterone at cut off level 20 ng/ml was 95.1% sensitive to diagnose non-viable pregnancy and was 98.9% specific to diagnose viable pregnancy. Serum progesterone is a reliable marker for early pregnancy failure and single assay of its serum level can differentiate between viable and non-viable pregnancies

    Efficacy and timing of adjunctive therapy in the anti-VEGF treatment regimen for macular oedema in retinal vein occlusion:12-month real-world result

    Get PDF
    PurposeVarious combination treatment regimens have been tried to improve the short-term efficacy of intravitreal monotherapy for the treatment of macular oedema (MO) secondary to retinal vein occlusion (RVO). Our study introduces the RandOL protocol (Ranibizumab and Ozurdex with Laser photocoagulation) of initial anti-VEGF therapy, controlling recurrent non-ischaemic MO with an intravitreal steroid and applying laser therapy to non-perfused retina. We describe our 12-month follow-up experience on timing for adjunctive therapy and real-world effectiveness and safety data.MethodsA retrospective analysis was carried out on 66 consecutive treatment-naive RVO patients with MO who received our RandOL treatment regimen. Baseline visual acuity (VA) and central retinal thickness (CRT) were compared with 12-month result.ResultsAt 12 months, 77% had significant VA improvement, 52% had ≥3-line improvement, and 15% were worse. Significant improvements in CRT were observed in 97% (baseline median CRT=531 μm (IQR 435-622) reduced to 245 μm (IQR 221-351, P<0.001) at 12 months); 76% achieved a dry fovea at 1 year. Mean number of total injections required was 5.5 (range 2-11) and 6% required ≥9 injections in 1 year. Although 70% received additional Ozurdex, 82% received ≥1 sessions of laser therapy. The BRVO subgroup achieved better VA and CRT improvement at 1 year, but small numbers limit definitive statistical conclusions.ConclusionsOur real-world results using a combination treatment protocol for RVO-related MO achieved similar desirable anatomical and visual outcomes as with a single-agent therapy with less intravitreal re-treatment rates at first year. Randomised controlled studies are needed to evaluate the role of laser and the ideal timing of combination therapy

    Obstetric opinions regarding the method of delivery in women that have had surgery for retinal detachment

    Get PDF
    OBJECTIVES: We sought to determine international obstetric opinions regarding the influence of a history of rhegmatogenous retinal detachment on the management of labour and to review the evidence base. DESIGN: A questionnaire containing closed questions, with pre-coded response opinions, was designed to obtain a cross-section of the obstetric opinions. SETTING: Questionnaires were distributed at the 20th European Congress of Obstetrics and Gynaecology in Lisbon, Portugal. PARTICIPANTS: One hundred questionnaires were distributed among obstetricians attending the congress and 74 agreed to participate. MAIN OUTCOME MEASURES: Participants were asked to state their preferred method of delivery in such patients and the reasons for their recommendation. Furthermore, we questioned whether there was any difference in opinions depending on generation. RESULTS: The majority of respondents (76%) would recommend assisted delivery (either Caesarean section or instrumental delivery), whereas the remaining 24% would advise normal delivery. Generation is not a factor influencing this decision. The majority (58%) based their decision to alter the management of labour on their personal opinion of standard of care. CONCLUSION: The literature shows that there is little evidence to support the belief that previous retinal surgery increases the risk of re-detachment of the retina during spontaneous vaginal delivery. This short survey shows that the majority of an international sample of obstetricians questioned does not share this viewpoint. Therefore, unnecessary interventions may be occurring in otherwise fit women with a history of retinal detachment

    The Children and Young People's Health Partnership Evelina London Model of Care: process evaluation protocol

    Get PDF
    Introduction Children and young people (CYP) in the UK have poor health outcomes, and there is increasing emergency department and hospital outpatient use. To address these problems in Lambeth and Southwark (two boroughs of London, UK), the local Clinical Commissioning Groups, Local Authorities and Healthcare Providers formed The Children and Young People’s Health Partnership (CYPHP), a clinical-academic programme for improving child health. The Partnership has developed the CYPHP Evelina London model, an integrated healthcare model that aims to deliver effective, coordinated care in primary and community settings and promote better self-management to over approximately 90 000 CYP in Lambeth and Southwark. This protocol is for the process evaluation of this model of care. Methods and analysis Alongside an impact evaluation, an in-depth, mixed-methods process evaluation will be used to understand the barriers and facilitators to implementing the model of care. The data collected mapped onto a logic model of how CYPHP is expected to improve child health outcomes. Data collection and analysis include qualitative interviews and focus groups with stakeholders, a policy review and a quantitative analysis of routine clinical and administrative data and questionnaire data. Information relating to the context of the trial that may affect implementation and/or outcomes of the CYPHP model of care will be documented. Ethics and dissemination The study has been reviewed by NHS REC Cornwall & Plymouth (17/SW/0275). The findings of this process evaluation will guide the scaling up and implementation of the CYPHP Evelina London Model of Care across the UK. Findings will be disseminated through publications and conferences, and implementation manuals and guidance for others working to improve child health through strengthening health systems. Trial registration number NCT03461848

    Laparoscopy in management of appendicitis in high-, middle-, and low-income countries: a multicenter, prospective, cohort study.

    Get PDF
    BACKGROUND: Appendicitis is the most common abdominal surgical emergency worldwide. Differences between high- and low-income settings in the availability of laparoscopic appendectomy, alternative management choices, and outcomes are poorly described. The aim was to identify variation in surgical management and outcomes of appendicitis within low-, middle-, and high-Human Development Index (HDI) countries worldwide. METHODS: This is a multicenter, international prospective cohort study. Consecutive sampling of patients undergoing emergency appendectomy over 6 months was conducted. Follow-up lasted 30 days. RESULTS: 4546 patients from 52 countries underwent appendectomy (2499 high-, 1540 middle-, and 507 low-HDI groups). Surgical site infection (SSI) rates were higher in low-HDI (OR 2.57, 95% CI 1.33-4.99, p = 0.005) but not middle-HDI countries (OR 1.38, 95% CI 0.76-2.52, p = 0.291), compared with high-HDI countries after adjustment. A laparoscopic approach was common in high-HDI countries (1693/2499, 67.7%), but infrequent in low-HDI (41/507, 8.1%) and middle-HDI (132/1540, 8.6%) groups. After accounting for case-mix, laparoscopy was still associated with fewer overall complications (OR 0.55, 95% CI 0.42-0.71, p < 0.001) and SSIs (OR 0.22, 95% CI 0.14-0.33, p < 0.001). In propensity-score matched groups within low-/middle-HDI countries, laparoscopy was still associated with fewer overall complications (OR 0.23 95% CI 0.11-0.44) and SSI (OR 0.21 95% CI 0.09-0.45). CONCLUSION: A laparoscopic approach is associated with better outcomes and availability appears to differ by country HDI. Despite the profound clinical, operational, and financial barriers to its widespread introduction, laparoscopy could significantly improve outcomes for patients in low-resource environments. TRIAL REGISTRATION: NCT02179112

    A Novel Interturn Fault Tolerant-Based Average Torque Control of Switched Reluctance Motors for Electric Vehicles

    Get PDF
    Because of their attractive features, switched reluctance motors (SRMs) are strong candidates with real chances on the market for several industrial applications including vehicle propulsion. However, the SRMs suffer from torque ripple and associated acoustic noise. A proper control algorithm can handle torque ripples to an accepted limit. However, the internal faults in stator windings of SRMs deteriorate not only the performance of control algorithm but also the output power, efficiency, and noise (torque ripple). They cause fast degradation of motor lifetime. Therefore, this paper introduces a novel method to counteract the internal faults in winding of SRMs. A new simulation method for SRMs including the capability of interturn faults is introduced. The proposed novel interturn fault tolerant control (FTC) is achieved based on average torque control (ATC) algorithm. The switching angles are optimized smartly providing a less complicated control algorithm to fit properly with the industrial platforms. The simplicity of overall control algorithm is still functional. The performance of proposed FTC is evaluated compared to healthy motor conditions as well as faulty conditions. The results show the superior performance of the proposed control. © 2013 IEEE

    RNF20-mediated transcriptional pausing and VEGFA splicing orchestrate vessel growth

    Get PDF
    Signal-responsive gene expression is essential for vascular development, yet the mechanisms integrating signaling inputs with transcriptional activities are largely unknown. Here we show that RNF20, the primary E3 ubiquitin ligase for histone H2B, plays a multifaceted role in sprouting angiogenesis. RNF20 mediates RNA polymerase (Pol II) promoter-proximal pausing at genes highly paused in endothelial cells, involved in VEGFA signaling, stress response, cell cycle control and mRNA splicing. It also orchestrates large-scale mRNA processing events that alter the bioavailability and function of critical pro-angiogenic factors, such as VEGFA. Mechanistically, RNF20 restricts ERG-dependent Pol II pause release at highly paused genes while binding to Notch1 to promote H2B monoubiquitination at Notch target genes and Notch-dependent gene expression. This balance is crucial, as loss of Rnf20 leads to uncontrolled tip cell specification. Our findings highlight the pivotal role of RNF20 in regulating VEGF-Notch signaling circuits during vessel growth, underscoring its potential for therapeutic modulation of angiogenesis

    Productivity and Thermal Performance Enhancements of Hollow Fiber Water Gap Membrane Distillation Modules Using Helical Fiber Configuration: 3D Computational Fluid Dynamics Modeling

    Get PDF
    Although hollow fiber water gap membrane distillation (HF-WGMD) units offer certain advantages over other MD desalination systems, they still require enhancements in terms of distillate flux and productivity. Therefore, this work proposes a novel configuration by incorporating the helical turns of HF membranes within the water gap channel of the HF-WGMD modules. A fully coupled 3D CFD model is developed and validated to simulate the multifaceted energy conservations and diffusion mechanisms that are inherent to the transport phenomena in the proposed HF-WGMD module. Single and double helical HF membrane designs with different numbers of turns are compared to the reference modules of single and double straight HF membrane designs under various operational conditions. At a feed temperature of 70 °C, a noteworthy 11.4% enhancement in the distillate flux is observed when employing 20 helical turns, compared to the single straight HF membrane module. Furthermore, the specific productivity revealed a maximum enhancement of 46.2% when using 50 helical turns. The thermal performance of the proposed HF-WGMD module shows higher energy savings of up to 35% in specific thermal energy consumption for a one-stage module. Using three stages of single helical modules can increase the gain output ratio from 0.17 for the single stage to 0.37, which represents an increase of 117.6%. These findings indicate the high potential of the proposed approach in advancing the performance of HF-WGMD systems

    Performance of Layer-by-Layer-Modified Multibore® Ultrafiltration Capillary Membranes for Salt Retention and Removal of Antibiotic Resistance Genes

    Get PDF
    Polyether sulfone Multibore® ultrafiltration membranes were modified using polyelectrolyte multilayers via the layer-by-layer (LbL) technique in order to increase their rejection capabilities towards salts and antibiotic resistance genes. The modified capillary membranes were characterized to exhibit a molecular weight cut-off (at 90% rejection) of 384 Da. The zeta-potential at pH 7 was −40 mV. Laboratory tests using single-fiber modified membrane modules were performed to evaluate the removal of antibiotic resistance genes; the LbL-coated membranes were able to completely retain DNA fragments from 90 to 1500 nt in length. Furthermore, the pure water permeability and the retention of single inorganic salts, MgSO4_{4}, CaCl2_{2} and NaCl, were measured using a mini-plant testing unit. The modified membranes had a retention of 80% toward MgSO4_{4} and CaCl2_{2} salts, and 23% in case of NaCl. The modified membranes were also found to be stable against mechanical backwashing (up to 80 LMH) and chemical regeneration (in acidic conditions and basic/oxidizing conditions)
    corecore