323 research outputs found

    Mie plasmons: modes volumes, quality factors and coupling strengths (Purcell factor) to a dipolar emitter

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    Using either quasi-static approximation or exact Mie expansion, we characterize the localized surface plasmons supported by a metallic spherical nanoparticle. We estimate the quality factor QnQ_n and define the effective volume VnV_n of the nthn^{th} mode in a such a way that coupling strength with a neighbouring dipolar emitter is proportional to the ratio Qn/VnQ_n/V_n (Purcell factor). The role of Joule losses, far-field scattering and mode confinement in the coupling mechanism are introduced and discussed with simple physical understanding, with particular attention paid to energy conservation.Comment: (in press) International Journal of Optics (2011

    Long-term outcome and health-related quality of life in difficult-to-wean patients with and without ventilator dependency at ICU discharge : a retrospective cohort study

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    Background: Long-term outcome and quality of life (QOL) in patients requiring prolonged mechanical ventilation after failure to wean in the ICU is scarcely documented. We aimed to evaluate long-term survival and QOL in patients discharged from the ICU with a tracheostomy for difficult weaning, and with or without ventilator dependency at ICU discharge. Methods: We retrospectively investigated post-ICU trajectories and survival in patients requiring tracheostomy for difficult weaning admitted to the medical ICU of a tertiary center between 1999 and 2013, discriminating between patients who were ventilator dependent or were weaned at ICU discharge. In 2014, a QOL assessment was done in survivors with the use of the Short Form Health Survey (SF-36) and the Severe Respiratory Insufficiency questionnaire. Results: A total of 114 patients was included, of whom 59 were ventilator dependent and 55 were weaned at ICU discharge. One-year survival rates were 73 % and 69 %, respectively. Overall QOL scores for physical functioning were low, and not significantly different between patients ventilated and those weaned at ICU discharge; scores for social functioning and mental health were less below norm and similar between both groups. Conclusions: Long-term survival in patients discharged from the ICU with tracheostomy and ventilator dependency after failure to wean was not significantly different from that of patients with tracheostomy and weaned at ICU discharge. Despite the physical QOL scores being low in both groups, mental QOL was acceptable. Given the intrinsic limitations of this retrospective study, prospective and preferentially multicenter studies are required to confirm these preliminary results

    Placental mitochondrial DNA content is associated with childhood intelligence

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    Background: Developmental processes in the placenta and the fetal brain are shaped by the similar biological signals. Evidence accumulates that adaptive responses of the placenta may influence central nervous system development. We hypothesize that placental mtDNA content at birth is associated with intelligence in childhood. In addition, we investigate if intra-pair differences in mtDNA content are associated with intra-pair differences in intelligence. Methods: Relative mtDNA content was measured using qPCR in placental tissue of 375 children of the East Flanders Prospective Twin Survey. Intelligence was assessed with the Wechsler Intelligence Scale for Children-Revised (WISC-R) between 8 and 15 years old. We accounted for sex, gestational age, birth weight, birth year, zygosity and chorionicity, cord insertion, age at measurement, indicators of socioeconomic status, smoking during pregnancy, and urban environment. Results: In multivariable adjusted mixed modelling analysis, each doubling in placental mtDNA content was associated with 2.0 points (95% CI 0.02 to 3.9; p = 0.05) higher total and 2.3 points (95% CI 0.2 to 4.3; p = 0.03) higher performance IQ in childhood. We observed no association between mtDNA content and verbal intelligence. Intra-pair differences in mtDNA content and IQ were significantly (p = 0.01) correlated in monozygotic-monochorionic twin pairs, showing that the twin with the highest mtDNA content was 1.9 times more likely (p = 0.05) to have the highest IQ. This was not observed in dichorionic twin pairs. Conclusions: We provide the first evidence that placental mtDNA content is associated with childhood intelligence. This emphasizes the importance of placental mitochondrial function during in utero life on fetal brain development with long-lasting consequences

    Blood pressure in young adulthood and residential greenness in the early-life environment of twins

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    Background: Previous research shows that, besides risk factors in adult life, the early-life environment can influence blood pressure and hypertension in adults. However, the effects of residential traffic exposure and residential greenness in the early-life on blood pressure in young adulthood are currently unknown. Methods: Ambulatory (24-h) blood pressures of 278 twins (132 pairs) of the East Flanders Prospective Twins Study were obtained at the age of 18 to 25 years. Prenatal and adulthood residential addresses were geocoded and used to assign prenatal and postnatal traffic and greenness indicators. Mixed modelling was performed to investigate blood pressure in association with greenness while adjusting for potential confounding factors. Results: Night-time systolic blood pressure was inversely associated with greenness at the residential address in twins living at the same address their entire life (non-movers, n = 97, 34.9%). An interquartile increase in residential greenness exposure (1000 m radius) was associated with a 3.59 mmHg (95% CI: -6.0 to -1.23; p = 0.005) lower adult night systolic blood pressure. Among twins who were living at a different address than their birth address at time of the measurement (n = 181, 65.1%), night-time blood pressure was inversely associated with residential surrounding greenness at adult age as well as with residential greenness in early-life. However after additional adjustment for residential greenness exposure in adulthood, only residential greenness exposure in early-life was significantly associated with night systolic blood pressure. While no significant effect of adult residential greenness with adult blood pressure was observed, while accounting for the early-life greenness exposure. Conclusions: Lower residential greenness in the early-life environment was independently associated with a higher adult blood pressure. This indicates that residential greenness has persistent effects on blood pressure

    Endurance and Resistance Training in Radically Treated Respiratory Cancer patients: A Pilot Study

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    Introduction. Respiratory cancer and its treatment are known to contribute to muscle weakness and functional impairment. Aim. To assess the effects of rehabilitation in patients with respiratory cancer. Methods. Radically treated respiratory cancer patients were included in a 12-week multidisciplinary rehabilitation program. Results. 16 patients (age: 61 ± 7 years; FEV1: 57 ± 16% pred.) showed a reduced exercise tolerance (VO2max: 56 ± 15% pred.; 6 MWD: 67 ± 11% pred.), muscle force (PImax: 54 ± 22% pred.; QF: 67 ± 16% pred.), and quality of life (CRDQd: 17 ± 5 points; CRDQf: 16 ± 5 points). Exercise tolerance, muscle force, and quality of life improved significantly after rehabilitation. Conclusion. Radically treated patients with respiratory cancer have a decreased exercise capacity, muscle force, and quality of life. 12 weeks of rehabilitation leads to a significant improvement in exercise capacity, respiratory muscle force, and quality of life

    Telomere tracking from birth to adulthood and residential traffic exposure

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    Background: Telomere attrition is extremely rapid during the first years of life, while lifestyle during adulthood exerts a minor impact. This suggests that early life is an important period in the determination of telomere length. We investigated the importance of the early-life environment on both telomere tracking and adult telomere length. Methods: Among 184 twins of the East Flanders Prospective Twin Survey, telomere length in placental tissue and in buccal cells in young adulthood was measured. Residential addresses at birth and in young adulthood were geocoded and residential traffic and greenness exposure was determined. Results: We investigated individual telomere tracking from birth over a 20 year period (mean age (SD), 22.6 (3.1) years) in association with residential exposure to traffic and greenness. Telomere length in placental tissue and in buccal cells in young adulthood correlated positively (r = 0.31, P < 0.0001). Persons with higher placental telomere length at birth were more likely to have a stronger downward shift in telomere ranking over life (P < 0.0001). Maternal residential traffic exposure correlated inversely with telomere length at birth. Independent of birth placental telomere length, telomere ranking between birth and young adulthood was negatively and significantly associated with residential traffic exposure at the birth address, while traffic exposure at the residential address at adult age was not associated with telomere length. Conclusions: Longitudinal evidence of telomere length tracking from birth to adulthood shows inverse associations of residential traffic exposure in association with telomere length at birth as well as accelerated telomere shortening in the first two decades of life

    Educating Generation Z About Gender Equality in Sport

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    The GETZ (Gender Equality Toolkit for Generation Z) project aims to develop, deliver and evaluate an innovative educational resource specifically designed for generation z on the issues relating to gender equality and equal opportunities in sport. In order to understand the perceptions, attitudes and actions related to gender equality and equal opportunities in sport among generation z, undergraduate students from four research institutions involved in the GETZ-project were recruited and a total of eight focus groups were conducted. Data was elicited thought questions regarding: (1)Their perceptions and experiences of gender equality; (2) Personal commitment and attitudes to gender equality; and (3) Any specific actions they had taken or behaviours they had engaged in to promote gender equality or alleviate gender inequality. These questions were informed by the pre-agreed MOOC units of the GETZ Toolkit which are: Culture & Society, Governance & Law, Commerce, Media, Participation, and Events. Preliminary findings indicate that there were common perceptions and experiences among students from Generation Z across all four participating institutions and countries and that there was an outspoken advantage for males in the sport industry, in terms of governance, media and behaviour

    Monozygotic multiple gestation following in vitro fertilization: analysis of seven cases from Japan

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    We present a series of monozygous multiple gestations achieved following in vitro fertilization (IVF): one case of monochorionic triplet pregnancy and six cases of dizygotic triplet pregnancy. From September 2000 to December 2006, all patients achieving clinical pregnancy by ART were reviewed (n = 2433). A 37 year-old woman who delivered a healthy singleton after IVF returned two years later for FET, and a single blastocyst was transferred. This also resulted in pregnancy, but TV-USG revealed a single gestational sac with three distinct amniotic sacs, each containing a distinct fetal pole with cardiac activity. This pregnancy was electively terminated at nine weeks' gestation. An additional six cases of dizygotic triplets established after fresh embryo transfer (no ICSI or assisted hatching) are also described. Of these, one resulted in a miscarriage at eight weeks' gestation and five patients have an ongoing pregnancy. This case series suggests the incidence of dizygotic/monochorionic triplets following IVF is approximately 10 times higher than the expected rate in unassisted conceptions, and underscores the importance of a conservative approach to lower the number of embryos at transfer. The role of embryo transfer technique and in vitro culture media in the twinning process requires further study
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