66 research outputs found

    Bonding bare die LEDs on PET foils for lighting applications: thermal design modeling and bonding experiments

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    Integration of LEDs on flexible foil substrates is of interest for flexible lighting applications and flexible photonic devices. A matrix of LEDs on a foil combined with a diffuser can be a potential alternative for flexible OLED lighting devices. Preferably, these LEDs are integrated in an unpackaged, bare die form as it reduces cost, footprint and thickness. As a substrate, preferably low cost materials like polyesters (PET) are being used, especially for large area devices. However, the use of these materials imposes some limitations. Most notably, the low temperature stability (<100 degrees C continuous use temperature) of these materials limits the maximum temperatures during the manufacturing process and poses constraints on the thermal design of the device. The current paper describes the results of research on possibilities for integrating bare die LEDs with low cost flexible PET foils. Finite element (FE) thermal modeling has been performed of possible designs of adhesively bonded LED-on-foil and laminated LED-in-foil configurations. The role of the different materials and the effect of their geometries on the temperature distribution in the simulated devices are discussed. The results give insight in measures that can be taken to keep the temperature of all the components of the device within operational limits. For LEDs bonded on Cu-PET foil the modeled temperature distributions are compared to experimentally observed temperature distributions in LED on PET foil reference devices using infrared thermal imaging. Besides this, initial studies on directly bonding LEDs on etched Cu on PET substrates using anisotropic conducting adhesives and isotropic conducting adhesives were performed. An experimental comparison is made between the different techniques based on temperature/humidity reliability and flexural stability of the bonded LEDs, based on these preliminary results

    Reliability of residents' assessments of their postgraduate medical education learning environment:an observational study

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    Background: Even in anonymous evaluations of a postgraduate medical education (PGME) program, residents may be reluctant to provide an honest evaluation of their PGME program, because they fear embarrassment or repercussions from their supervisors if their anonymity as a respondent is endangered. This study was set up to test the hypothesis that current residents in a PGME program provide more positive evaluations of their PGME program than residents having completed it. We therefore compared PGME learning environment evaluations of current residents in the program to leaving residents having completed it. Methods: This observational study used data gathered routinely in the quality cycle of PGME programs at two Dutch teaching hospitals to test our hypothesis. At both hospitals, all current PGME residents are requested to complete the Scan of Postgraduate Education Environment Domains (SPEED) annually. Residents leaving the hospital after completion of the PGME program are also asked to complete the SPEED after an exit interview with the hospital's independent residency coordinator. All SPEED evaluations are collected and analysed anonymously. We compared the residents' grades (on a continuous scale ranging from 0 (poor) to 10 (excellent)) on the three SPEED domains (content, atmosphere, and organization of the program) and their mean (overall department grade) between current and leaving residents. Results: Mean (SD) overall SPEED department grades were 8.00 (0.52) for 287 current residents in 39 PGME programs and 8.07 (0.48) for 170 leaving residents in 39 programs. Neither the overall SPEED department grades (t test, p = 0.53, 95% CI for difference -0.16 to 0.31) nor the department SPEED domain grades (MANOVA, F(3, 62) = 0.79, p = 0.51) were significantly different between current and leaving residents. Conclusions: Residents leaving the program did not provide more critical evaluations of their PGME learning environment than current residents in the program. This suggests that current residents' evaluations of their postgraduate learning environment were not affected by social desirability bias or fear of repercussions from faculty

    Correlation between clinical course and quantitative analysis of the ischemia related artery in patients with unstable angina pectoris, refractory to medical treatment

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    Patients with unstable angina, refractory to intensive medical therapy, are at high risk for developing thrombotic complications, such as recurrent ischemia, myocardial infarction and coronary occlusion during coronary angioplasty. As both platelet ag

    Characteristics, treatment and outcome of patients with non-ST-elevation acute coronary syndromes and multivessel coronary artery disease: observations from PURSUIT (Platelet Glycoprotein IIb/IIIa in unstable angina: receptor suppression using integreling therapy)

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    BACKGROUND: The 6-month clinical outcome of patients with multivessel disease enrolled in PURSUIT (Platelet Glycoprotein IIb/IIIa in Unstable Angina: Receptor Suppression Using Integrilin Therapy) is described. Patients with complete angiography data were included; multivessel disease was stratified according to the treatment strategy applied early during hospitalization, i.e. medical treatment, percutaneous coronary intervention (PCI) (balloon), PCI (stent), or coronary artery bypass grafting (CABG). METHODS: Patients were divided into three groups according to the treatment strategy applied during the first 30 days of enrolment. Patients who did not undergo a percutaneous or surgical coronary intervention were classified as medically treated. Patients who underwent a PCI (prior to a possible CABG) were separated from those who underwent a CABG (prior to a possible PCI). The PCI group was further subdivided: patients receiving >/=1 coronary stents were separated from those in whom no stents were used. RESULTS: The mortality rate at 30 days was 6.7, 3.9, 2.4 and 4.8% for the medical treatment, PCI (balloon), PCI (stent) and CABG groups, respectively (p value = 0.002). Differences as observed at 30 days were still present at 6-month follow-up with 11.1, 5.8, 5.5 and 6.5% mortality event rates for the aforementioned groups (p value = 0.002). The 30-day myocardial infarction (MI) rate according to the opinion of the Clinical Events Committee was lower among medically than non-medically treated patients, with the highest event rate observed in the CABG group (27.7%). Approximately half of the MIs in the PCI and CABG subgroups occurred within 48 h after the procedure. CONCLUSIONS: The observed differences in clinical outcomes are explained by an imbalance in baseline characteristics and comorbid conditions between the analyzed groups of patients

    ABO-incompatible kidney transplantation in perspective of deceased donor transplantation and induction strategies:a propensity-matched analysis

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    BACKGROUND: Kidney transplant candidates are blood group incompatible with roughly one out of three potential living donors. We compared outcomes after ABO-incompatible (ABOi) kidney transplantation with matched ABO-compatible (ABOc) living and deceased donor transplantation and analyzed different induction regimens. METHODS: We performed a retrospective study with propensity matching and compared patient and death-censored graft survival after ABOi versus ABOc living donor and deceased donor kidney transplantation in a nationwide registry from 2006 till 2019. RESULTS: 296 ABOi were compared to 1184 center and propensity matched ABOc living donor and 1184 deceased donor recipients (matching: recipient age, sex, blood group and PRA). Patient survival was better compared to deceased donor (hazard ratio (HR) for death of HR 0.69 [0.49-0.96], and not-significantly different from ABOc living donor recipients (HR 1.28 [0.90-1.81]). Rate of graft failure was higher compared to ABOc living donor transplantation (HR 2.63 [1.72-4.01]). Rejection occurred in 47% of 140 rituximab versus 22% of 50 rituximab/basiliximab, and 4% of 92 alemtuzumab treated recipients (p <0.001). CONCLUSIONS: ABOi kidney transplantation is superior to deceased donor transplantation. Rejection rate and graft failure are higher compared to matched ABOc living donor transplantation, underscoring the need for further studies into risk stratification and induction therapy

    Catch-up growth up to ten years of age in children born very preterm or with very low birth weight

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    BACKGROUND: Improved survival due to advances in neonatal care has brought issues such as postnatal growth and development more to the focus of our attention. Most studies report stunting in children born very preterm and/or small for gestational age. In this article we study the growth pattern of these children and aim to identify factors associated with postnatal catch-up growth. METHODS: 1338 children born with a gestational age <32 weeks and/or a birth weight of <1500 grams were followed during a Dutch nationwide prospective study (POPS). Subgroups were classified as appropriate for gestational age and <32 weeks (AGA) or small for gestational age (<32 wks SGA and ≥32 wks SGA). Data were collected at different intervals from birth until 10 years for the 962 survivors and compared to reference values. The correlation between several factors and growth was analysed. RESULTS: At 10 years the AGA children had attained normal height, whereas the SGA group demonstrated stunting, even after correction for target height (AGA: 0.0 SDS; SGA <32 wks: -0.29SDS and ≥32 wks: -0.13SDS). Catch-up growth was especially seen in the SGA children with a fast initial weight gain. BMI was approximately 1 SD below the population reference mean. CONCLUSION: At 10 years of age, children born very preterm AGA show no stunting. However, many children born SGA, especially the very preterm, show persistent stunting. Early weight gain seems an important prognostic factor in predicting childhood growth

    Rationale and design of The Delphi Trial – I(RCT)(2): international randomized clinical trial of rheumatoid craniocervical treatment, an intervention-prognostic trial comparing 'early' surgery with conservative treatment [ISRCTN65076841]

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    BACKGROUND: Rheumatoid arthritis is a chronic inflammatory disease, which affects 1% of the population. Hands and feet are most commonly involved followed by the cervical spine. The spinal column consists of vertebrae stabilized by an intricate network of ligaments. Especially in the upper cervical spine, rheumatoid arthritis can cause degeneration of these ligaments, causing laxity, instability and subluxation of the vertebral bodies. Subsequent compression of the spinal cord and medulla oblongata can cause severe neurological deficits and even sudden death. Once neurological deficits occur, progression is inevitable although the rapidity of progression is highly variable. The first signs and symptoms are pain at the back of the head caused by compression of the major occipital nerve, followed by loss of strength of arms and legs. The severity of the subluxation can be observed with radiological investigations (MRI, CT) with a high sensitivity. The authors have sent a Delphi Questionnaire about the current treatment strategies of craniocervical involvement by rheumatoid arthritis to an international forum of expert rheumatologists and surgeons. The timing of surgery in patients with radiographic instability without evidence of neurological deficit is an area of considerable controversy. If signs and symptoms of myelopathy are present there is little chance of recovery to normal levels after surgery. DESIGN: In this international multicenter randomized clinical trial, early surgical atlantoaxial fixation in patients with rheumatoid arthritis and radiological abnormalities without neurological deficits will be compared with prolonged conservative treatment. The main research question is whether early surgery can prevent radiological and neurological progression. A cost-effectivity analysis will be performed. 250 patients are needed to answer the research question. DISCUSSION: Early surgery could prevent serious neurological deficits, but may have peri-operative morbidity and loss of rotation of the head and neck. The objective of this study is to identify the best timing of surgery for patients at risk for the development of neurological signs and symptoms

    Displaced midshaft fractures of the clavicle: non-operative treatment versus plate fixation (Sleutel-TRIAL). A multicentre randomised controlled trial

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    Contains fulltext : 96826.pdf (publisher's version ) (Open Access)BACKGROUND: The traditional view that the vast majority of midshaft clavicular fractures heal with good functional outcomes following non-operative treatment may be no longer valid for all midshaft clavicular fractures. Recent studies have presented a relatively high incidence of non-union and identified speciic limitations of the shoulder function in subgroups of patients with these injuries. AIM: A prospective, multicentre randomised controlled trial (RCT) will be conducted in 21 hospitals in the Netherlands, comparing fracture consolidation and shoulder function after either non-operative treatment with a sling or a plate fixation. METHODS/DESIGN: A total of 350 patients will be included, between 18 and 60 years of age, with a dislocated midshaft clavicular fracture. The primary outcome is the incidence of non-union, which will be determined with standardised X-rays (Antero-Posterior and 30 degrees caudocephalad view). Secondary outcome will be the functional outcome, measured using the Constant Score. Strength of the shoulder muscles will be measured with a handheld dynamometer (MicroFET2). Furthermore, the health-related Quality of Life score (ShortForm-36) and the Disabilities of Arm, Shoulder and Hand (DASH) Outcome Measure will be monitored as subjective parameters. Data on complications, bone union, cosmetic aspects and use of painkillers will be collected with follow-up questionnaires. The follow-up time will be two years. All patients will be monitored at regular intervals over the subsequent twelve months (two and six weeks, three months and one year). After two years an interview by telephone and a written survey will be performed to evaluate the two-year functional and mechanical outcomes. All data will be analysed on an intention-to-treat basis, using univariate and multivariate analyses. DISCUSSION: This trial will provide level-1 evidence for the comparison of consolidation and functional outcome between two standardised treatment options for dislocated midshaft clavicular fractures. The gathered data may support the development of a clinical guideline for treatment of clavicular fractures. TRIAL REGISTRATION: Netherlands National Trial Register NTR2399
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