1,008 research outputs found

    Light trapping in ultrathin plasmonic solar cells

    Get PDF
    We report on the design, fabrication, and measurement of ultrathin film a-Si:H solar cells with nanostructured plasmonic back contacts, which demonstrate enhanced short circuit current densities compared to cells having flat or randomly textured back contacts. The primary photocurrent enhancement occurs in the spectral range from 550 nm to 800 nm. We use angle-resolved photocurrent spectroscopy to confirm that the enhanced absorption is due to coupling to guided modes supported by the cell. Full-field electromagnetic simulation of the absorption in the active a-Si:H layer agrees well with the experimental results. Furthermore, the nanopatterns were fabricated via an inexpensive, scalable, and precise nanopatterning method. These results should guide design of optimized, non-random nanostructured back reflectors for thin film solar cells

    A translational rat model for ex vivo lung perfusion of pre-injured lungs after brain death

    Get PDF
    The process of brain death (BD) detrimentally affects donor lung quality. Ex vivo lung perfusion (EVLP) is a technique originally designed to evaluate marginal donor lungs. Nowadays, its potential as a treatment platform to repair damaged donor lungs is increasingly studied in experimental models. Rat models for EVLP have been described in literature before, yet the pathophysiology of BD was not included in these protocols and prolonged perfusion over 3 hours without anti-inflammatory additives was not achieved. We aimed to establish a model for prolonged EVLP of rat lungs from brain-dead donors, to provide a reliable platform for future experimental studies. Rat lungs were randomly assigned to one of four experimental groups (n = 7/group): 1) healthy, directly procured lungs, 2) lungs procured from rats subjected to 3 hours of BD and 1 hour cold storage (CS), 3) healthy, directly procured lungs subjected to 6 hours EVLP and 4), lungs procured from rats subjected to 3 hours of BD, 1 hour CS and 6 hours EVLP. Lungs from brain-dead rats showed deteriorated ventilation parameters and augmented lung damage when compared to healthy controls, in accordance with the pathophysiology of BD. Subsequent ex vivo perfusion for 6 hours was achieved, both for lungs of healthy donor rats as for pre-injured donor lungs from brain-dead rats. The worsened quality of lungs from brain-dead donors was evident during EVLP as well, as corroborated by deteriorated ventilation performance, increased lactate production and augmented inflammatory status during EVLP. In conclusion, we established a stable model for prolonged EVLP of pre-injured lungs from brain-dead donor rats. In this report we describe tips and pitfalls in the establishment of the rat EVLP model, to enhance reproducibility by other researchers

    Generic nano-imprint process for fabrication of nanowire arrays

    Full text link
    A generic process has been developed to grow nearly defect free arrays of (heterostructured) InP and GaP nanowires. Soft nanoimprint lithography has been used to pattern gold particle arrays on full 2 inch substrates. After lift-off organic residues remain on the surface, which induce the growth of additional undesired nanowires. We show that cleaning of the samples before growth with piranha solution in combination with a thermal anneal at 550 C for InP and 700 C for GaP results in uniform nanowire arrays with 1% variation in nanowire length, and without undesired extra nanowires. Our chemical cleaning procedure is applicable to other lithographic techniques such as e-beam lithography, and therefore represents a generic process.Comment: 12 pages, 4 figures, 2 table

    Pregnancy outcomes in asylum seekers in the North of the Netherlands:a retrospective documentary analysis

    Get PDF
    BACKGROUND: With more than 20,000 asylum seekers arriving every year, healthcare for this population has become an important issue. Pregnant asylum seekers seem to be at risk of poor pregnancy outcomes. This study aimed to assess the difference in pregnancy outcomes between asylum seekers and the local Dutch population and to identify potential substandard factors of care. METHODS: Using a retrospective study design we compared pregnancy outcomes of asylum-seeking and Dutch women who gave birth in a northern region of the Netherlands between January 2012 and December 2016. The following data were compared: perinatal mortality, maternal mortality, gestational age at delivery, preterm delivery, birth weight, small for gestational age children, APGAR score, intrauterine foetal death, mode of delivery and the need for pain medication. Cases of perinatal mortality in asylum seekers were reviewed for potential substandard factors. RESULTS: A total of 344 Asylum-seeking women and 2323 Dutch women were included. Asylum seekers had a higher rate of perinatal mortality (3.2% vs. 0.6%, p = 0.000) including a higher rate of intrauterine foetal death (2.3% vs. 0.2%, p = 0.000), higher gestational age at birth (39 + 4 vs. 38 + 6 weeks, p = 0.000), labour was less often induced (36.9 vs. 43.8, p = 0.016), postnatal hospitalization was longer (2.24 vs. 1.72 days p = 0.006) and they received more opioid analgesics (27.3% vs. 22%, p = 0.029). Babies born from asylum-seeking women had lower birth weights (3265 vs. 3385 g, p = 0.000) and were more often small for gestational age (13.9% vs. 8.4%, p = 0.002). Multivariate analysis showed that the increased risk of perinatal mortality in asylum-seeking women was independent of parity, birth weight and gestational age at birth. Review of the perinatal mortality cases in asylum seekers revealed possible substandard factors, such as late initiation of antenatal care, missed appointments because of transportation problems, not recognising alarm symptoms, not knowing who to contact and transfer to other locations during pregnancy. CONCLUSION: Pregnant asylum seekers have an increased risk of adverse pregnancy outcomes. More research is needed to identify which specific risk factors are involved in poor perinatal outcomes in asylum seekers and to identify strategies to improve perinatal care for this group of vulnerable women

    Crossing barriers:a multidisciplinary approach to children and adults with young-onset movement disorders

    Get PDF
    Abstract Background Diagnosis of less common young-onset movement disorders is often challenging, requiring a broad spectrum of skills of clinicians regarding phenotyping, normal and abnormal development and the wide range of possible acquired and genetic etiologies. This complexity often leads to considerable diagnostic delays, paralleled by uncertainty for patients and their families. Therefore, we hypothesized that these patients might benefit from a multidisciplinary approach. We report on the first 100 young-onset movement disorders patients who visited our multidisciplinary outpatient clinic. Methods Clinical data were obtained from the medical records of patients with disease-onset before age 18 years. We investigated whether the multidisciplinary team, consisting of a movement disorder specialist, pediatric neurologist, pediatrician for inborn errors of metabolism and clinical geneticist, revised the movement disorder classification, etiological diagnosis, and/or treatment. Results The 100 referred patients (56 males) had a mean age of 12.5 ± 6.3 years and mean disease duration of 9.2 ± 6.3 years. Movement disorder classification was revised in 58/100 patients. Particularly dystonia and myoclonus were recognized frequently and supported by neurophysiological testing in 24/29 patients. Etiological diagnoses were made in 24/71 (34%) formerly undiagnosed patients, predominantly in the genetic domain. Treatment strategy was adjusted in 60 patients, of whom 43 (72%) reported a subjective positive effect. Conclusions This exploratory study demonstrates that a dedicated tertiary multidisciplinary approach to complex young-onset movement disorders may facilitate phenotyping and improve recognition of rare disorders, with a high diagnostic yield and minimal diagnostic delay. Future studies are needed to investigate the cost-benefit ratio of a multidisciplinary approach in comparison to regular subspecialty care

    Childbirths and the Prevalence of Potential Risk Factors for Adverse Perinatal Outcomes among Asylum Seekers in The Netherlands:A Five-Year Cross-Sectional Study

    Get PDF
    This five-year cross-sectional study mapped the prevalence of several known risk factors for adverse perinatal outcomes in asylum-seeking women in The Netherlands. Characteristics of 2831 registered childbirths among residents of asylum seekers centers (ASCs) in The Netherlands from 2016 to 2020 were included. Results showed a high general and teenage birthrate (2.15 and 6.77 times higher compared to the Dutch, respectively). Most mothers were pregnant upon arrival, and the number of births was highest in the second month of stay in ASCs. Another peak in births between 9 and 12 months after arrival suggested that many women became pregnant shortly after arrival in The Netherlands. Furthermore, 69.5 percent of all asylum-seeking women were relocated between ASCs at least once during pregnancy, which compromises continuity of care. The high prevalence of these risk factors in our study population might explain the increased rate of adverse pregnancy outcomes in asylum seekers compared to native women found in earlier studies. Incorporating migration-related indicators in perinatal health registration is key to support future interventions, policies, and research. Ultimately, our findings call for tailored and timely reproductive and perinatal healthcare for refugee women who simultaneously face the challenges of resettlement and pregnancy

    Lung transplantation for acute respiratory distress syndrome:A multicenter experience

    Get PDF
    Acute respiratory distress syndrome (ARDS) is a rapidly progressive lung disease with a high mortality rate. Although lung transplantation (LTx) is a well-established treatment for a variety of chronic pulmonary diseases, LTx for acute lung failure (due to ARDS) remains controversial. We reviewed posttransplant outcome of ARDS patients from three high-volume European transplant centers. Demographics and clinical data were collected and analyzed. Viral infection was the main reason for ARDS (n = 7/13, 53.8%). All patients were admitted to ICU and required mechanical ventilation, 11/13 were supported with ECMO at the time of listing. They were granted a median LAS of 76 (IQR 50-85) and waited for a median of 3 days (IQR 1.5-14). Postoperatively, median length of mechanical ventilation was 33 days (IQR 17-52.5), median length of ICU and hospital stay were 39 days (IQR 19.5-58.5) and 54 days (IQR 43.5-127). Prolongation of peripheral postoperative ECMO was required in 7/13 (53.8%) patients with a median duration of 2 days (IQR 2-7). 30-day mortality was 7.7%, 1 and 5-year survival rates were calculated as 71.6% and 54.2%, respectively. Given the lack of alternative treatment options, the herein presented results support the concept of offering live-saving LTx to carefully selected ARDS patients

    Is logistically motivated ex vivo lung perfusion a good idea?

    Get PDF
    Ex vivo lung perfusion (EVLP) is a technique for reconditioning and evaluating lungs. However, the use of EVLP for logistical reasons is still under discussion. In this retrospective study, all EVLPs performed between July 2012 and October 2019 were analyzed for ventilation and perfusion data. After transplantation, primary graft dysfunction (PGD), lung function, chronic lung allograft dysfunction (CLAD)-free survival, and overall survival were analyzed. Fifty EVLPs were performed: seventeen logistic EVLPs led to 15 lung transplantations (LT) and two rejections (LR), and 33 medical EVLPs resulted in 26 lung transplantations (MT) and seven rejections (MR). Pre-EVLP PaO2 was lower for MT than LT (p &lt; 0.05). Dynamic lung compliance remained stable in MT and LT but decreased in MR and LR. Plateau airway pressure started at a higher level in MR (p &lt; 0.05 MT vs. MR at T60) and increased further in LR. After transplantation, there were no differences between MT and LT in PGD, lung function, CLAD-free survival, and overall survival. In addition, the LT group was compared with a cohort group receiving standard donor lungs without EVLP (LTx). There were no significant differences between LT and LTx for PGD, CLAD-free survival, and overall survival. FVC was significantly lower in LT than in LTx after 1 year (p = 0.005). We found that LT lungs appear to perform better than MT lungs on EVLP. In turn, the outcome in the LT group was comparable with the LTx group. Overall, lung transplantation after EVLP for logistic reasons is safe and makes transplantation timing controllable.<br/

    Patient-reported health outcomes in long-term lung transplantation survivors

    Get PDF
    During the last three decades lung transplantation (LTx) has become a proven modality for increasing both survival and health-related quality of life (HRQoL) in patients with various end-stage lung diseases. Most previous studies have reported improved HRQoL shortly after LTx. With regard to long-term effects on HRQoL, however, the evidence is less solid. This prospective cohort study was started with 828 patients who were on the waiting list for LTx. Then, in a longitudinal follow-up, 370 post-LTx patients were evaluated annually for up to 15 years. For all wait-listed and follow-up patients, the following four HRQoL instruments were administered: State-Trait Anxiety Inventory, Zung Self-rating Depression Scale, Nottingham Health Profile, and a visual analogue scale. Cross-sectional and generalized estimating equation (GEE) analysis for repeated measures were performed to assess changes in HRQoL during follow-up. After LTx, patients showed improvement in all HRQoL domains except pain, which remained steady throughout the long-term follow-up. The level of anxiety and depressive symptoms decreased significantly and remained constant. In conclusion, this study showed that HRQoL improves after LTx and tends to remain relatively constant for the entire life span
    • …
    corecore