Objective To evaluate the effects of operator experience on perinatal outcome in a single centre.Design Prospective consecutive cohort study.Setting Regional tertiary referral Fetal Medicine Centre in the UK.Population Pregnant women with monochorionic twin pregnancies complicated by severe twin-to-twin transfusion syndrome (TTTS) (at £26 completed weeks of gestatiuon) treated by fetoscopic laser coagulation (FLC) between October 2004 and November 2009.Methods Pregnancy characteristics and outcomes were collected. Logistic regression analysis was employed to determine the effect of a priori defined variables on outcome.Main outcome measure Perinatal survival (survival to 28 days or beyond) for one or more twins.Results There were 164 consecutive sets of monochorionic twins. The median gestational age (GA) at FLC was 20.4 weeks (interquartile range 18-22.1 weeks), the median interval from FLC to delivery was 88.5 days (interquartile range 53-101 days) and the median GA at delivery was 33.2 weeks (interquartile range 29.7-34.9 weeks). The overall survival was 62%; perinatal survival of one or more twins was 85%. These outcomes improved after about 61 procedures were performed, and after about 3.4 years of experience. Univariate logistic regression analysis indicated that Quintero stage-IV disease decreased (OR 0.26; 95% CI 0.10-0.69) and prolongation of GA at delivery increased the survival of the twins (OR 1.34; 95% CI 1.12-1.60) (P < 0.01). Increasing experience of the procedure by operator led to a significant increase in perinatal survival (P < 0.01; OR 4.59; 95% CI 1.84-11.44). Multivariate logistic regression analysis indicated that only GA at delivery increased survival overall (OR 1.34; 95% CI 1.12-1.60; P = 0.01).Conclusions These data indicate that both relatively large numbers treated and experience with FLC minimises any adverse outcome in monochorionic pregnancies with severe TTTS.Keywords Fetoscopic laser, perinatal outcome, Twin-to-twin transfusion syndrome.Please cite this paper as: Morris R, Selman T, Harbidge A, Martin W, Kilby M. Fetoscopic laser coagulation for severe twin-to-twin transfusion syndrome: factors influencing perinatal outcome, learning curve of the procedure and lessons for new centres.

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The emissive properties of both doped and non-doped graphene quantum dots (GQDs) with sizes ranging from 3-11 nm were analyzed at the single particle level. Both doped and nondoped GQDs are a composite of particles exhibiting green, red, or NIR fluorescence on excitation at 488, 561, and 640 nm, respectively. Nitrogen doped GQDs (N-GQDs) with diameters ranging from 3.4 to 5.2 nm show a larger proportion of particles with NIR emission as compared to non-doped particles. and the fluorescence intermittency seen in single GQD particles. While ms to sec time scale blinking was regularly observed for red emitting non-doped GQDs, nitrogen doping significantly reduced blinking. Both doped and non-doped particles also exhibit moderate size dependent photophysical properties.

A-B-C-model, human resource management, legal, moral principles, workplace bullying,

The effect of gold and aluminum zero-mode waveguides (ZMWs) on the brightness of immobilized single emitters was characterized by probing fluorophores that absorb in the green and red regions of the visible spectrum. Aluminum ZMWs enhance the emission of Atto565 fluorophores upon green excitation, but they do not enhance the emission of Atto647N fluorophores upon red excitation. Gold ZMWs increase emission of both fluorophores with Atto647N showing enhancement that is threefold higher than that observed for Atto565. This work indicates that 200 nm gold ZMWs are better suited for single-molecule fluorescence studies in the red region of the visible spectrum, while aluminum appears more suited for the green region of the visible spectrum.