891 research outputs found
Shape complexity and fractality of fracture surfaces of swelled isotactic polypropylene with supercritical carbon dioxide
We have investigated the fractal characteristics and shape complexity of the
fracture surfaces of swelled isotactic polypropylene Y1600 in supercritical
carbon dioxide fluid through the consideration of the statistics of the islands
in binary SEM images. The distributions of area , perimeter , and shape
complexity follow power laws , , and , with the scaling ranges spanning
over two decades. The perimeter and shape complexity scale respectively as
and in two scaling regions delimited by . The fractal dimension and shape complexity increase when the temperature
decreases. In addition, the relationships among different power-law scaling
exponents , , , , and have been derived analytically,
assuming that , , and follow power-law distributions.Comment: RevTex, 6 pages including 7 eps figure
Negative curves on algebraic surfaces
We study curves of negative self-intersection on algebraic surfaces. We
obtain results for smooth complex projective surfaces X on the number of
reduced, irreducible curves C of negative self-intersection C^2. The only known
examples of surfaces for which C^2 is not bounded below are in positive
characteristic, and the general expectation is that no examples can arise over
the complex numbers. Indeed, we show that the idea underlying the examples in
positive characteristic cannot produce examples over the complex number field.
The previous version of this paper claimed to give a counterexample to the
Bounded Negativity Conjecture. The idea of the counterexample was to use Hecke
translates of a smooth Shimura curve in order to create an infinite sequence of
curves violating the Bounded Negativity Conjecture. To this end we applied
Hirzebruch Proportionality to all Hecke translates, simultaneously
desingularized by a version of Jaffee's Lemma which exists in the literature
but which turns out to be false. Indeed, in the new version of the paper, we
show that only finitely many Hecke translates of a special subvariety of a
Hilbert modular surface remain smooth. This new result is based on work done
jointly with Xavier Roulleau, who has been added as an author. The other
results in the original posting of this paper remain unchanged.Comment: 14 pages, X. Roulleau added as author, counterexample to Bounded
Negativity Conjecture withdrawn and replaced by a proof that there are only
finitely many smooth Shimura curves on a compact Hilbert modular surface; the
other results in the original posting of this paper remain unchange
Observing non-classical crystallisation processes in gypsum via infrared attenuated total reflectance spectroscopy
The nature of crystallisation processes is of major interest, as they are among the most frequently occurring reactions associated with a variety of relevant processes in chemistry, biochemistry, and geochemistry. In this study, an innovative approach towards fundamentally understanding crystallisation pathways in a seemingly simple system-gypsum-has been developed via infrared spectroscopic techniques. Specifically, infrared attenuated total reflection spectroscopy (IR-ATR) was instrumental in revealing detailed information on inter- and intramolecular interactions during gypsum crystallization via subtle changes in the vibrational spectra of the involved reactants. When applying D2O as an isotope marker, it was shown that isotopically labelled water may serve as a viable spectroscopic probe during mid-infrared (3-15 µm) studies providing unique insight into the crystallization process at molecular-level detail. In addition, it was revealed that H2O and D2O give rise to distinctly different reaction kinetics during the crystallization process
Heterogeneity of gestational diabetes (GDM) and challenges in developing a GDM risk score
AimsGestational diabetes (GDM) affects a growing number of women and identification of individuals at risk, e.g., with risk prediction models, would be important. However, the performance of GDM risk scores has not been optimal. Here, we assess the impact of GDM heterogeneity on the performance of two top-rated GDM risk scores.MethodsThis is a substudy of the RADIEL triala lifestyle intervention study including women at high GDM risk. We assessed the GDM risk score by Teede and that developed by Van Leeuwen in our high-risk cohort of 510 women. To investigate the heterogeneity of GDM, we further divided the women according to GDM history, BMI, and parity. With the goal of identifying novel predictors of GDM, we further analyzed 319 women with normal glucose tolerance in the first trimester.ResultsBoth risk scores underestimated GDM incidence in our high-risk cohort. Among women with a BMI30kg/m(2) and/or previous GDM, 49.4% developed GDM and 37.4% received the diagnosis already in the first trimester. Van Leeuwen score estimated a 19% probability of GDM and Teede succeeded in risk identification in 61%. The lowest performance of the risk scores was seen among the non-obese women. Fasting plasma glucose, HbA(1c), and family history of diabetes were predictors of GDM in the total study population. Analysis of subgroups did not provide any further information.ConclusionsOur findings suggest that the marked heterogeneity of GDM challenges the development of risk scores for detection of GDM.Peer reviewe
Effect of maternal lifestyle intervention on metabolic health and adiposity of offspring : Findings from the Finnish Gestational Diabetes Prevention Study (RADIEL)
Aim. - To assess in women at high risk of gestational diabetes mellitus (GDM) the effect of a lifestyle intervention on the metabolic health of their offspring around 5 years after delivery. Methods. - For the original Finnish gestational diabetes prevention study (RADIEL), 720 women with a prepregnancy body mass index (BMI) >= 30 kg/m(2) and/or previous GDM were enrolled before or during early pregnancy and allocated to either an interventional (n = 126) or conventional (n = 133) care group. The present 5-year follow-up substudy assessed the metabolic health outcomes of their offspring. Ageand gender-standardized residuals of metabolic health components (waist circumference, mean arterial pressure, high-density lipoprotein and triglyceride levels, and fasting insulin/glucose ratio) were also combined to determine the accumulation of metabolic effects. Body composition was assessed by electrical bioimpedance. Results. - Offspring of women in the intervention group had a less optimal metabolic profile after the 5-year follow-up compared with offspring in the usual care group (P = 0.014). This difference in metabolic health was primarily related to lipid metabolism, and was more prominent among boys (P = 0.001) than girls (P = 0.74). Neither GDM, gestational weight gain, prepregnancy BMI, offspring age nor timing of randomization (before or during pregnancy) could explain the detected difference, which was also more pronounced among the offspring of GDM pregnancies (P= 0.010). Offspring body composition was similar in both groups (P> 0.05). Conclusion. - The lifestyle intervention aimed at GDM prevention was associated with unfavourable metabolic outcomes among offspring at around 5 years of age. (C) 2019 Elsevier Masson SAS. All rights reserved.Peer reviewe
Perceived Financial Satisfaction, Health Related Quality of Life and depressive Symptoms in Early Pregnancy
Objectives To assess the associations of perceived financial satisfaction and health-related quality of life (HRQoL) and depressive symptoms in an unselected pregnant population in early pregnancy. Methods 750 consecutive pregnant women attending the first communal ultrasound examination before gestational week 14 were invited to participate. Questionnaires assessing HRQoL (15D), depressive symptoms (Edinburgh Depression Scale, EPDS), medical, obstetric, and socioeconomic status were handed out. The participants were divided into three groups according to their satisfaction with their financial status, (unsatisfied, somewhat satisfied, and satisfied). Main outcome measures were 15D and EPDS-scores and dimensions of HRQoL. Results 325 (43,3%) questionnaires were returned. The mean 15D-score for HRQoL was 0,926 (SD 0,056). The financially unsatisfied women had lower HRQoL than women in more satisfied groups (0.906, 0.923 and 0.931, p = 0.012). The result remained significant, even after adjusting for age and education(p = 0.032). The unsatisfied women had a higher mean body mass index (BMI) (25.4, 24.4 and 23.2 kg/m(2), p for linearity = 0.002), were more often smokers, (13 vs. 4 and 3%, p = 0.029), and had experienced at least one abortion (18, 14 and 7%, p = 0.017). Dimensions of depression, distress and sleep explained the differences between the groups. 27% of unsatisfied women scored EPDS ae10 points suggesting increased risk of depression. Conclusions Financial satisfaction in early pregnancy associates with HRQoL and risk of perinatal depressive symptoms. Unsatisfied women more often have risk factors for unfavourable pregnancy outcomes which may influence the later health and wellbeing of the mother and child.Peer reviewe
Heterogeneity of gestational diabetes (GDM) and long-term risk of diabetes and metabolic syndrome : findings from the RADIEL study follow-up
To assess the metabolic health of obese and non-obese women at high GDM risk 5 years postpartum. This is a secondary analysis of the 5-year follow-up of the RADIEL GDM prevention study including 333 women at high GDM risk (BMI ae 30 kg/m(2) and/or previous GDM). Five years postpartum metabolic health was assessed including anthropometric measurements, oral glucose tolerance test, lipid metabolism, and body composition as well as medical history questionnaires. For the analysis, we divided the women into four groups based on parity, BMI, and previous history of GDM. Five years postpartum impaired glucose regulation (IFG, IGT, or diabetes) was diagnosed in 15% of the women; 3.6% had type 2 diabetes. The highest prevalence was observed among obese women with a history of GDM (26%), and the lowest prevalence (8%) among primiparous obese women (p = 0.021). At follow-up 25-39% of the obese women fulfilled the diagnostic criteria for the metabolic syndrome, in the non-obese group 11% (p <0.001). This was associated with body fat percentage. The non-obese group, however, faced metabolic disturbances (IFG, IGT, diabetes, or metabolic syndrome) at a significantly lower BMI (p <0.001). Among women who were non-obese before pregnancy, 5 years postpartum, the obesity prevalence based on BMI was 14% and based on body fat percentage 58%. The prevalence of impaired glucose regulation and metabolic syndrome is high 5 years postpartum among women at high risk of GDM. There are high-risk women also among the non-obese, who develop metabolic derangements already at a lower BMI.Peer reviewe
Physical activity and health-related quality of life among high-risk women for type 2 diabetes in the early years after pregnancy
Background Previous studies have shown that physical activity (PA) correlates positively with health-related quality of life (HRQoL) in the general population. Few studies have investigated associations between device-measured PA and HRQoL among premenopausal women at risk for type 2 diabetes (T2D). In addition to physical well-being, general well-being improved by PA has been suggested to strengthen PA's benefits in reducing metabolic diseases. The aim of this study was to examine the associations between PA and HRQoL (general and dimensions) among high-risk women in the early post-pregnancy years when T2D risk is highest and to estimate whether current obesity or prior gestational diabetes (GDM) modified these associations. Methods This cross-sectional study of high-risk women [body mass index (BMI) >= 30 kg/m(2) and/or prior GDM)]4-6 years after delivery measured sleep, sedentary time, daily steps, and light (LPA), moderate-to-vigorous (MVPA), and vigorous PA (VPA) with the SenseWear ArmbandTM accelerometer for seven days and HRQoL with the 15D instrument. Results The analyses included 204 women with a median (IQR) age of 39 (6.0) years and a median BMI of 31.1 kg/m(2) (10.9). 54% were currently obese (BMI >= 30 kg/m(2)), and 70% had prior gestational diabetes (GDM+). Women with obesity had lower PA levels than women with normal weight or overweight (p = 30 kg/m(2)), the associations remained significant only in women without obesity. Among them, sleep, total steps, MVPA, and VPA were positively associated with 15D. Conclusions Higher PA levels are associated with better HRQoL among high-risk women with normal weight and overweight but no differences were found among women affected by obesity in the early years after pregnancy. Trial registration Ethics committees of Helsinki University Hospital (Dnro 300/e9/06) and South Karelian Central Hospital (Dnro 06/08).Peer reviewe
- …