406 research outputs found

    Relationships between intrauterine fetal growth trajectories and markers of adiposity and inflammation in young adults

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    Background There is now good evidence that events during gestation significantly influence the developmental well-being of an individual in later life. This study aimed to investigate the relationships between intrauterine growth trajectories determined by serial ultrasound and subsequent markers of adiposity and inflammation in the 27-year-old adult offspring from the Raine Study, an Australian longitudinal pregnancy cohort. Methods Ultrasound fetal biometric measurements including abdominal circumference (AC), femur length (FL), and head circumference (HC) from 1333 mother-fetal pairs (Gen1–Gen2) in the Raine Study were used to develop fetal growth trajectories using group-based trajectory modeling. Linear mixed modeling investigated the relationship between adult body mass index (BMI), waist circumference (WC), and high-sensitivity C-reactive protein (hs-CRP) of Gen2 at 20 (n = 485), 22 (n = 421) and 27 (n = 437) years and the fetal growth trajectory groups, adjusting for age, sex, adult lifestyle factors, and maternal factors during pregnancy. Results Seven AC, five FL and five HC growth trajectory groups were identified. Compared to the average-stable (reference) group, a lower adult BMI was observed in two falling AC trajectories: (β = −1.45 kg/m2, 95% CI: −2.43 to −0.46, P = 0.004) and (β = −1.01 kg/m2, 95% CI: −1.96 to −0.05, P = 0.038). Conversely, higher adult BMI (2.58 kg/m2, 95% CI: 0.98 to 4.18, P = 0.002) and hs-CRP (37%, 95% CI: 9–73%, P = 0.008) were observed in a rising FL trajectory compared to the reference group. A high-stable HC trajectory associated with 20% lower adult hs-CRP (95% CI: 5–33%, P = 0.011). Conclusion This study highlights the importance of understanding causes of the unique patterns of intrauterine growth. Different fetal growth trajectories from early pregnancy associate with subsequent adult adiposity and inflammation, which predispose to the risk of diabetes and cardiometabolic disease

    Comparison of the cardiometabolic profiles of adolescents conceived through ART with those of a non-ART cohort

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    STUDY QUESTION Is the cardiometabolic health of adolescents conceived through ART worse than that of their counterparts conceived without ART? SUMMARY ANSWER The majority of cardiometabolic and vascular health parameters of adolescents conceived through ART are similar or more favourable, than those of their counterparts of similar age and conceived without ART. WHAT IS KNOWN ALREADY It has been proposed that the cardiometabolic health of offspring conceived with ART may be unfavourable compared to that of their counterparts conceived without ART. The literature pertaining to cardiometabolic health of offspring conceived after ART is contradictory, but generally suggests unfavourable cardiometabolic health parameters, such as an increase in blood pressure (BP), vascular dysfunction and adiposity, as well as unfavourable glucose and lipid profiles. With over 8 million children and adults born through ART worldwide, it is important to investigate whether these early signs of adverse cardiometabolic differences persist into adolescence and beyond. STUDY DESIGN, SIZE, DURATION The Growing Up Healthy Study (GUHS) is a prospective cohort study that recruited 303 adolescents and young adults conceived after ART (aged 13–21 years) and born between 1991 and 2001 in Western Australia. Their health parameters, including cardiometabolic factors, were assessed and compared with counterparts from the Raine Study Generation 2 (Gen2). The 2868 Gen2 participants were born 1989–1992 and are representative of the Western Australian adolescent population. At ∼17 years of age (2013–2017), 163 GUHS participants replicated assessments previously completed by Gen2 at a similar age. PARTICIPANTS/MATERIALS, SETTING, METHODS Cardiometabolic parameters were compared between a total of 163 GUHS and 1457 Gen2 adolescents. Separate male (GUHS n = 81, Gen2 n = 735) and female (GUHS n = 82, Gen2 n = 722) analyses were conducted. Assessments consisted of a detailed questionnaire including health, lifestyle and demographic parameters, anthropometric assessments (height, weight, BMI, waist circumference and skinfold thickness), fasting serum biochemistry, arterial stiffness and BP (assessed using applanation tonometry). Abdominal ultrasonography was used to assess the presence and severity of hepatic steatosis, and thickness of abdominal fat compartments. Non-alcoholic fatty liver disease (NAFLD) was diagnosed if there was sonographic fatty liver in the absence of significant alcohol consumption. Chi2, Fisher’s exact and Mann–Whitney U tests, performed in SPSS V25, examined cohort differences and generalized estimating equations adjusted for the following covariates: singleton vs non-singleton pregnancy, birthweight (z-score), gestational age, BMI, smoking, alcohol consumption in the past 6 months and parent cardiovascular status. Arterial stiffness measures and waist circumference were additionally adjusted for height, and female analyses were additionally adjusted for use of oral contraceptives in the preceding 6 months. MAIN RESULTS AND THE ROLE OF CHANCE In adjusted analyses, GUHS females had a lower BMI (22.1 vs 23.3 kg/m2, P = 0.014), and thinner skinfolds (triceps, subscapular, mid-abdominal; 16.9 vs 18.7 mm, P = 0.021, 13.4 vs 15.0 mm, P = 0.027, 19.7 vs 23.2 mm, P < 0.001, respectively), whereas males were not significantly different. Waist circumference was lower in GUHS adolescents (males: 78.1 vs 81.3 cm, P = 0.008, females: 76.7 vs 83.3 cm, P = 0.007). There were no significant differences between the two groups in glucose, insulin, homeostatic model assessment for insulin resistance, low-density lipoprotein cholesterol, non-high-density lipoprotein cholesterol (non-HDL-C), total cholesterol (TC), alanine aminotransferase and high-sensitivity C-reactive protein in both sexes. In females, serum triglycerides were lower in GUHS adolescents (1.0 vs 1.2 mmol/l, P = 0.029). GUHS males had higher serum HDL-C (1.1 vs 1.0 mmol/l, P = 0.004) and a lower TC/HDL-C ratio (3.2 vs 3.6, P = 0.036). There were no significant differences in the prevalence of NAFLD or steatosis severity scores between the cohorts in males and females. GUHS females had less subcutaneous adipose tissue (9.4 vs 17.9 mm, P < 0.001), whereas GUHS males had greater visceral adipose thickness (44.7 vs 36.3 mm, P < 0.001). There was no significant difference in pre-peritoneal adipose thickness. Pulse wave velocity was lower in GUHS males (5.8 vs 6.3 m/s, P < 0.001) and heart rate corrected augmentation index was lower in GUHS females (−8.4 vs −2.7%, P = 0.048). There were no significant differences in BP or heart rate in males or females between the two groups. LIMITATIONS, REASONS FOR CAUTION Despite the substantial study size and the unique study design of the ART cohort, we were unable to differentiate between different types of ART, due to the low number of ICSI cycles (e.g. IVF vs ICSI), draw definite conclusions, or relate the outcomes to the cause of infertility. Considering the differences in time points when both cohorts were studied, external factors could have changed, which could not be accounted for. Given the observational nature of this study, causation cannot be proven. WIDER IMPLICATIONS OF THE FINDINGS Contrary to our hypothesis and previous findings focussing mainly on childhood, this study reports mostly similar or favourable cardiometabolic markers in adolescents conceived with ART compared to those conceived without ART. The greater visceral adipose thickness, particularly present in males, requires further investigation. While these findings are generally reassuring, future well-designed and appropriately powered studies are required to definitively address the issue of cardiometabolic health in ART adults. STUDY FUNDING/COMPETING INTEREST(S) This project was supported by NHMRC project grant number 1042269 and R.J.H. received education grant funding support from Ferring Pharmaceuticals. R.J.H. is the Medical Director of Fertility Specialists of Western Australia and a shareholder in Western IVF. He has received educational sponsorship from MSD, Merck-Serono and Ferring Pharmaceuticals. P.B. is the Scientific Director of Concept Fertility Centre, Subiaco, Western Australia. J.L.Y. is the Medical Director of PIVET Medical Centre, Perth, Western Australia

    Lines on projective varieties and applications

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    The first part of this note contains a review of basic properties of the variety of lines contained in an embedded projective variety and passing through a general point. In particular we provide a detailed proof that for varieties defined by quadratic equations the base locus of the projective second fundamental form at a general point coincides, as a scheme, with the variety of lines. The second part concerns the problem of extending embedded projective manifolds, using the geometry of the variety of lines. Some applications to the case of homogeneous manifolds are included.Comment: 15 pages. One example removed; one remark and some references added; typos correcte

    Omega-3 polyunsaturated fatty acids: Their potential role in blood pressure prevention and management

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    Omega-3 polyunsaturated fatty acids (PUFAs) from fish and fish oils appear to protect against coronary heart disease: their dietary intake is in fact inversely associated to cardiovascular disease morbidity/mortality in population studies. Recent evidence suggests that at least part of their heart protective effect is mediated by a relatively small but significant decrease in blood pressure level. In fact, omega-3 PUFAs exhibit wide-ranging biological actions that include regulating both vasomotor tone and renal sodium excretion, partly competing with omega-6 PUFAs for common metabolic enzymes and thereby decreasing the production of vasocostrincting rather than vasodilating and anti-inflammatory eicosanoids. PUFAs also reduce angiotensin-converting enzyme (ACE) activity, angiotensin II formation, TGF-beta expression, enhance eNO generation and activate the parasympathetic nervous system. The final result is improved vasodilation and arterial compliance of both small and large arteries. Preliminary clinical trials involving dyslipidemic patients, diabetics and elderly subjects, as well as normotensive and hypertensive subjects confirm this working hypothesis. Future research will clarify if PUFA supplementation could improve the antihypertensive action of specific blood pressure lowering drug classes and of statins

    Omega-3 Index, fish consumption, use of fish oil supplements and first clinical diagnosis of central nervous system demyelination

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    Higher intakes of omega-3 polyunsaturated fatty acids (n3PUFAs) have been associated with lower MS risk. We aimed to test associations between the Omega-3 Index, blood levels of n3PUFAs, fish oil supplement use, and fish consumption with a first clinical diagnosis of CNS demyelination (FCD). Cases (n = 250) had a higher Omega-3 Index compared with a matched group of controls (n = 471) (average treatment effect (ATE)=0.31, p = 0.047, based on augmented inverse probability weighting). A higher percentage of cases than controls used fish oil supplements (cases=17% vs. controls=10%). We found that Omega-3 Index increased as time between FCD and study interview increased (e.g., at or below median (112 days), based on ATE, mean=5.30, 95% CI 5.08, 5.53; above median, mean=5.90, 95% CI 5.51, 6.30). Fish oil supplement use increased in a similar manner (at or below median (112 days), based on ATE, proportion=0.12, 95% CI 0.06, 0.18; above the median, proportion=0.21, 95% CI 0.14, 0.28). Our results suggest a behaviour change post FCD with increased use of fish oil supplements

    Condensation and evaporation of R32/R1234ze(E) and R744/R32/R1234ze(E) flow in horizontal microfin tubes

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    The heat transfer characteristics of the low global warming potential refrigerant mixture R744/R32/R1234ze(E) in a horizontal microfin tube were investigated in this study. The condensation heat transfer coefficient of R744 /R32/R1234ze(E) (9/29/62 mass %) is somewhat lower than that of other mixtures, e.g., R744/R32/R1234ze(E) (4/43/53 mass %) and R32/R1234ze(E) (40/60 mass %) and (30/70 mass %), at an average saturation temperature of 40?C, mass flux of 200 kg m?2s?1, and heat flux of 10 kWm?2. The temperature glides of R744/R32/R1234ze(E) (9/29/62 mass%) and (4/43/53 mass %) and R32/R1234ze(E) (30/70 mass %) and (40/60 mass %) are 18, 11, 10, and 8 K, respectively, at 40?C. Likewise, the magnitude of the heat transfer coefficient decrease is strongly affected by the temperature glide. The data for the evaporation heat transfer coefficient indicated similar effects of the temperature glide. At an average saturation temperature of 10?C, the evaporation heat transfer coefficient of R744/R32/R1234ze(E) (9/29/62 mass %) is slightly lower than that of other mixtures. The temperature glides of R744/R32/R1234ze(E) (9/29/62 mass %) and (4/43/53 mass%) and R32/R1234ze(E) (30/70 mass %) and (40/60 mass %) are 22, 13, 11, and 9 K, respectively. The pressure gradients of these refrigerants are almost equal, and the difference is within the measurement uncertainty. The experimental pressure gradient agrees well with the predictions proposed for single components

    Pulsar-wind nebulae and magnetar outflows: observations at radio, X-ray, and gamma-ray wavelengths

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    We review observations of several classes of neutron-star-powered outflows: pulsar-wind nebulae (PWNe) inside shell supernova remnants (SNRs), PWNe interacting directly with interstellar medium (ISM), and magnetar-powered outflows. We describe radio, X-ray, and gamma-ray observations of PWNe, focusing first on integrated spectral-energy distributions (SEDs) and global spectral properties. High-resolution X-ray imaging of PWNe shows a bewildering array of morphologies, with jets, trails, and other structures. Several of the 23 so far identified magnetars show evidence for continuous or sporadic emission of material, sometimes associated with giant flares, and a few possible "magnetar-wind nebulae" have been recently identified.Comment: 61 pages, 44 figures (reduced in quality for size reasons). Published in Space Science Reviews, "Jets and Winds in Pulsar Wind Nebulae, Gamma-ray Bursts and Blazars: Physics of Extreme Energy Release

    High order harmonics from relativistic electron spikes

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    A new regime of relativistic high-order harmonic generation is discovered [Phys. Rev. Lett. 108, 135004 (2012)]. Multi-terawatt relativistic-irradiance (>1018 W/cm2) femtosecond (~30-50 fs) lasers focused to underdense (few×1019 cm-3) plasma formed in gas jet targets produce comb-like spectra with hundreds of even and odd harmonic orders reaching the photon energy of 360 eV, including the 'water window' spectral range. Harmonics are generated by either linearly or circularly polarized pulses from the J-KAREN (KPSI, JAEA) and Astra Gemini (CLF, RAL, UK) lasers. The photon number scalability has been demonstrated with a 120 TW laser producing 40 μJ/sr per harmonic at 120 eV. The experimental results are explained using particle-in-cell (PIC) simulations and catastrophe theory. A new mechanism of harmonic generation by sharp, structurally stable, oscillating electron spikes at the joint of boundaries of wake and bow waves excited by a laser pulse is introduced. In this paper detailed descriptions of the experiments, simulations and model are provided and new features are shown, including data obtained with a two-channel spectrograph, harmonic generation by circularly polarized laser pulses and angular distribution
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