362 research outputs found

    Long-lived photoexcited states in polydiacetylenes with different molecular and supramolecular organization

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    With the aim of determining the importance of the molecular and supramolecular organization on the excited states of polydiacetylenes, we have studied the photoinduced absorption spectra of the red form of poly[1,6-bis(3,6-didodecyl-N-carbazolyl)-2,4-hexadiyne] (polyDCHD-S) and the results compared with those of the blue form of the same polymer. An interpretation of the data is given in terms of both the conjugation length and the interbackbone separation also in relation to the photoinduced absorption spectra of both blue and red forms of poly[1,6-bis(N-carbazolyl)-2,4-hexadiyne] (polyDCHD), which does not carry the alkyl substituents on the carbazolyl side groups. Information on the above properties is derived from the analysis of the absorption and Raman spectra of this class of polydiacetylenes

    Investigation of the association of Apgar score with maternal socio-economic and biological factors: an analysis of German perinatal statistics

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    PURPOSE: To examine the relationship of 5-min Apgar score with maternal socio-economic and biological factors. METHODS: We analyzed data from 465,964 singleton pregnancies (37–41 weeks’ gestation) from the German perinatal statistics of 1998–2000. Using a logistic regression model we analyzed the incidence of low (0–6) 5-min Apgar scores in relation to these maternal factors: body mass index (BMI), age, previous live births, country of origin, occupation, single mother status, working during pregnancy, and smoking. RESULTS: A low Apgar score was more common in overweight [adjusted odds ratio (OR) 1.24; 95% confidence interval (CI) 1.10–1.40; P < 0.001] and obese [OR 1.92 (95% CI 1.67–2.20); P < 0.001] compared to normal weight women. A low Apgar score was also more common for women aged >35 years compared to those aged 20–35 years [OR 1.35 (95% CI 1.16–1.58); P < 0.001]. Furthermore, odds of a low Apgar score were higher for women with no previous live births compared to those with one or more previous live births [OR 1.52 (95% CI 1.37–1.70); P < 0.001]. Socio-economic factors did not convincingly influence Apgar scores. CONCLUSIONS: There was an influence of the biological maternal factors age, BMI, and parity on the 5-min Apgar score. There was no convincing effect of socio-economic factors on Apgar score in our study population. Possible reasons for this are discussed

    Working towards an engagement turn to agricultural research in the Tonle Sap Biosphere,Cambodia

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    A new generation of agricultural research programs are embracing use of participation as a vehicle for achieving greater impact and supporting transformative change in complex social-ecological systems. In this paper, we share learning from use of participatory action research in the Tonle Sap biosphere in Cambodia, as the main implementing methodology within a large multi-partner agricultural research program. We describe the program’s espoused approach to applying participatory methodologies focusing on co-ownership, equity and reflexivity with stakeholders throughout the research process. We then reflect upon our practice as we pursued initiatives to support increased income and nutrition outcomes for the poorest people in a diverse aquatic agricultural system characterized by inequality. We discuss the challenges and early successes of the process and share three enabling conditions that support a shift towards quality of participation in agricultural research: (1) focusing at the outset on a strengthsbased mind-set, (2) staging a critical stance to progressively build equity in process and outcomes, and (3) institutionalizing reflexivity to facilitate ongoing learning

    Ultrasound-Guided Radiofrequency Thermal Ablation of Uterine Fibroids: Medium-Term Follow-Up

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    Previous studies have shown that radiofrequency thermal ablation (RFA) of uterine fibroids through a percutaneous ultrasound (US)-guided procedure is an effective and safe minimally invasive treatment, with encouraging short-term results. The aim of this study was to assess the results in terms of volume reduction and clinical symptoms improvement in the midterm follow-up of fibroids with a diameter of up to 8 cm. Eleven premenopausal females affected by symptomatic fibroids underwent percutaneous US-guided RFA. Symptom severity and reduction in volume were evaluated at 1, 3, 6, 9, and 12 months. The mean symptom score (SSS) before the procedure was 50.30 (range 31.8–67.30), and the average quality of life (QOL) score value was 62 (range 37.20–86.00). The mean basal diameter was 5.5 cm (range 4.4–8) and the mean volume was 101.5 cm3 (range 44.58–278 cm3). The mean follow-up was 9 months (range 3–12 months). The mean SSS value at the end of the follow-up was 13.38 (range 0–67.1) and the QOL 90.4 (range 43.8–100). At follow-up the mean diameter was 3.0 cm (range 1.20–4.5 cm), and the mean volume was 18 cm3 (range 0.90–47.6 cm3). In 10 of 11 patients we obtained total or partial regression of symptoms. In one case the clinical manifestations persisted and it was thus considered unsuccessful. In conclusion, US-guided percutaneous RFA is a safe and effective treatment even for fibroids up to 8 cm

    Infants in Control: Rapid Anticipation of Action Outcomes in a Gaze-Contingent Paradigm

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    Infants' poor motor abilities limit their interaction with their environment and render studying infant cognition notoriously difficult. Exceptions are eye movements, which reach high accuracy early, but generally do not allow manipulation of the physical environment. In this study, real-time eye tracking is used to put 6- and 8-month-old infants in direct control of their visual surroundings to study the fundamental problem of discovery of agency, i.e. the ability to infer that certain sensory events are caused by one's own actions. We demonstrate that infants quickly learn to perform eye movements to trigger the appearance of new stimuli and that they anticipate the consequences of their actions in as few as 3 trials. Our findings show that infants can rapidly discover new ways of controlling their environment. We suggest that gaze-contingent paradigms offer effective new ways for studying many aspects of infant learning and cognition in an interactive fashion and provide new opportunities for behavioral training and treatment in infants

    A novel cost function to estimate parameters of oscillatory biochemical systems

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    Oscillatory pathways are among the most important classes of biochemical systems with examples ranging from circadian rhythms and cell cycle maintenance. Mathematical modeling of these highly interconnected biochemical networks is needed to meet numerous objectives such as investigating, predicting and controlling the dynamics of these systems. Identifying the kinetic rate parameters is essential for fully modeling these and other biological processes. These kinetic parameters, however, are not usually available from measurements and most of them have to be estimated by parameter fitting techniques. One of the issues with estimating kinetic parameters in oscillatory systems is the irregularities in the least square (LS) cost function surface used to estimate these parameters, which is caused by the periodicity of the measurements. These irregularities result in numerous local minima, which limit the performance of even some of the most robust global optimization algorithms. We proposed a parameter estimation framework to address these issues that integrates temporal information with periodic information embedded in the measurements used to estimate these parameters. This periodic information is used to build a proposed cost function with better surface properties leading to fewer local minima and better performance of global optimization algorithms. We verified for three oscillatory biochemical systems that our proposed cost function results in an increased ability to estimate accurate kinetic parameters as compared to the traditional LS cost function. We combine this cost function with an improved noise removal approach that leverages periodic characteristics embedded in the measurements to effectively reduce noise. The results provide strong evidence on the efficacy of this noise removal approach over the previous commonly used wavelet hard-thresholding noise removal methods. This proposed optimization framework results in more accurate kinetic parameters that will eventually lead to biochemical models that are more precise, predictable, and controllable
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