147 research outputs found
Genomic analysis of diet composition finds novel loci and associations with health and lifestyle
We conducted genome-wide association study (GWAS) meta-analyses of relative caloric intake from fat,
protein, carbohydrates and sugar in over 235,000 individuals. We identified 21 approximately
independent lead SNPs. Relative protein intake exhibits the strongest relationships with poor health,
including positive genetic associations with obesity, type 2 diabetes, and heart disease ( â 0.15 â
0.5). Relative carbohydrate and sugar intake have negative genetic correlations with waist circumference,
waist-hip ratio, and neighborhood poverty (|| â 0.1 â 0.3). Overall, our results show that the relative
intake of each macronutrient has a distinct genetic architecture and pattern of genetic correlations
suggestive of health implications beyond caloric content
Comparison of four different treatment strategies in teeth with molar-incisor hypomineralization-related enamel breakdownâA retrospective cohort study
Background
There is little information available on the longevity of non-invasive glass ionomer cement (GIC) and composite restorations as well as conventional composite and ceramic restorations placed on permanent teeth with enamel breakdowns due to molar-incisor hypomineralization (MIH).
Aim
To compare the longevity of the abovementioned treatment procedures.
Design
Of 377 identified MIH patients, 118 individuals received restorative treatment and were invited for clinical examination, including caries and MIH status. Finally, survival data from 204 MIH-related restorations placed on 127 teeth were retrospectively collected from 52 children, monitored between 2010 and 2018. Descriptive and explorative analyses were performed, including Kaplan-Meier estimators and the Cox regression model.
Results
The mean patient observation time was 42.9 months (SD = 35.1). The cumulative survival probabilities after 36 monthsâ7.0% (GIC, N = 28), 29.9% (non-invasive composite restoration, N = 126), 76.2% (conventional composite restoration, N = 27) and 100.0% (ceramic restoration, N = 23)âdiffered significantly in the regression analysis.
Conclusions
Conventional restorations were associated with moderate-to-high survival rates in MIH teeth. In contrast, non-invasive composite restorations, which were predominately used in younger or less cooperative children, were linked to lower survival rates
Intake Design for an Atmosphere-Breathing Electric Propulsion System (ABEP)
Challenging space missions include those at very low altitudes, where the
atmosphere is source of aerodynamic drag on the spacecraft. To extend the
lifetime of such missions, an efficient propulsion system is required. One
solution is Atmosphere-Breathing Electric Propulsion (ABEP) that collects
atmospheric particles to be used as propellant for an electric thruster. The
system would minimize the requirement of limited propellant availability and
can also be applied to any planetary body with atmosphere, enabling new
missions at low altitude ranges for longer times. IRS is developing, within the
H2020 DISCOVERER project, an intake and a thruster for an ABEP system. The
article describes the design and simulation of the intake, optimized to feed
the radio frequency (RF) Helicon-based plasma thruster developed at IRS. The
article deals in particular with the design of intakes based on diffuse and
specular reflecting materials, which are analysed by the PICLas DSMC-PIC tool.
Orbital altitudes km and the respective species based on the
NRLMSISE-00 model (O, , , He, Ar, H, N) are investigated for several
concepts based on fully diffuse and specular scattering, including hybrid
designs. The major focus has been on the intake efficiency defined as
, with the incoming particle
flux, and the one collected by the intake. Finally, two
concepts are selected and presented providing the best expected performance for
the operation with the selected thruster. The first one is based on fully
diffuse accommodation yielding to and the second one based un
fully specular accommodation yielding to . Finally, also the
influence of misalignment with the flow is analysed, highlighting a strong
dependence of in the diffuse-based intake while, ...Comment: Accepted Versio
Cable-driven parallel robot for curtain wall module installation
A cable-driven parallel robot (CDPR) was developed for the installation of curtain wall modules (CWM). The research addressed the question of whether the CDPR was capable installing CWMs with sufficient accuracy while being competitive compared to conventional manual methods. In order to develop and test such a system, a conceptual framework that consisted of three sub-systems was defined. The tests, carried out in two close-to-real demonstration buildings, revealed an absolute accuracy of the CWM installation of 4 to 23 mm. The working time for installing a CWM was reduced to 0.51 h. The results also show that the system is competitive for a workspace greater than 96 m2 compared to conventional manual methods. However, improvements such as reducing the hours for setting up the CDPR on the one hand and achieving a faster and more robust MEE on the other hand will be still necessary in the future.This project has received funding from the European Unionâs Horizon 2020 research and innovation program under grant
agreement No. 73251
In-orbit aerodynamic coefficient measurements using SOAR (Satellite for Orbital Aerodynamics Research)
The Satellite for Orbital Aerodynamics Research (SOAR) is a CubeSat mission, due to be launched in 2021, to investigate the interaction between different materials and the atmospheric flow regime in very low Earth orbits (VLEO). Improving knowledge of the gasâsurface interactions at these altitudes and identification of novel materials that can minimise drag or improve aerodynamic control are important for the design of future spacecraft that can operate in lower altitude orbits. Such satellites may be smaller and cheaper to develop or can provide improved Earth observation data or communications link-budgets and latency. In order to achieve these objectives, SOAR features two payloads: (i) a set of steerable fins which provide the ability to expose different materials or surface finishes to the oncoming flow with varying angle of incidence whilst also providing variable geometry to investigate aerostability and aerodynamic control; and (ii) an ion and neutral mass spectrometer with time-of-flight capability which enables accurate measurement of the in-situ flow composition, density, velocity. Using precise orbit and attitude determination information and the measured atmospheric flow characteristics the forces and torques experienced by the satellite in orbit can be studied and estimates of the aerodynamic coefficients calculated. This paper presents the scientific concept and design of the SOAR mission. The methodology for recovery of the aerodynamic coefficients from the measured orbit, attitude, and in-situ atmospheric data using a least-squares orbit determination and free-parameter fitting process is described and the experimental uncertainty of the resolved aerodynamic coefficients is estimated. The presented results indicate that the combination of the satellite design and experimental methodology are capable of clearly illustrating the variation of drag and lift coefficient for differing surface incidence angle. The lowest uncertainties for the drag coefficient measurement are found at approximately 300 km, whilst the measurement of lift coefficient improves for reducing orbital altitude to 200 km
Intake design for an Atmosphere-Breathing Electric Propulsion System (ABEP)
Challenging space missions include those at very low altitudes, where the atmosphere is source of aerodynamic drag on the spacecraft. To extend the lifetime of such missions, an efficient propulsion system is required. One solution is Atmosphere-Breathing Electric Propulsion (ABEP) that collects atmospheric particles to be used as propellant for an electric thruster. The system would minimize the requirement of limited propellant availability and can also be applied to any planetary body with atmosphere, enabling new missions at low altitude ranges for longer times. IRS is developing, within the H2020 DISCOVERER project, an intake and a thruster for an ABEP system. The article describes the design and simulation of the intake, optimized to feed the radio frequency (RF) Helicon-based plasma thruster developed at IRS. The article deals in particular with the design of intakes based on diffuse and specular reflecting materials, which are analysed by the PICLas DSMC-PIC tool. Orbital altitudes and the respective species based on the NRLMSISE-00 model (O, , , He, Ar, H, N) are investigated for several concepts based on fully diffuse and specular scattering, including hybrid designs. The major focus has been on the intake efficiency defined as , with the incoming particle flux, and the one collected by the intake. Finally, two concepts are selected and presented providing the best expected performance for the operation with the selected thruster. The first one is based on fully diffuse accommodation yielding to and the second one based on fully specular accommodation yielding to . Finally, also the influence of misalignment with the flow is analysed, highlighting a strong dependence of in the diffuse-based intake while, for the specular-based intake, this is much lower finally leading to a more resilient design while also relaxing requirements of pointing accuracy for the spacecraft
Resource profile and user guide of the Polygenic Index Repository
Polygenic indexes (PGIs) are DNA-based predictors. Their value for research in many scientific disciplines is growing rapidly. As a resource for researchers, we used a consistent methodology to construct PGIs for 47 phenotypes in 11 datasets. To maximize the PGIsâ prediction accuracies, we constructed them using genome-wide association studies â some not previously published â from multiple data sources, including 23andMe and UK Biobank. We present a theoretical framework to help interpret analyses involving PGIs. A key insight is that a PGI can be understood as an unbiased but noisy measure of a latent variable we call the âadditive SNP factorâ. Regressions in which the true regressor is this factor but the PGI is used as its proxy therefore suffer from errors-in-variables bias. We derive an estimator that corrects for the bias, illustrate the correction, and make a Python tool for implementing it publicly available
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Clinical, environmental, and genetic risk factors for substance use disorders : characterizing combined effects across multiple cohorts
Substance use disorders (SUDs) incur serious social and personal costs. The risk for SUDs is complex, with risk factors ranging from social conditions to individual genetic variation. We examined whether models that include a clinical/environmental risk index (CERI) and polygenic scores (PGS) are able to identify individuals at increased risk of SUD in young adulthood across four longitudinal cohorts for a combined sample of N = 15,134. Our analyses included participants of European (N-EUR = 12,659) and African (N-AFR = 2475) ancestries. SUD outcomes included: (1) alcohol dependence, (2) nicotine dependence; (3) drug dependence, and (4) any substance dependence. In the models containing the PGS and CERI, the CERI was associated with all three outcomes (ORs = 01.37-1.67). PGS for problematic alcohol use, externalizing, and smoking quantity were associated with alcohol dependence, drug dependence, and nicotine dependence, respectively (OR = 1.11-1.33). PGS for problematic alcohol use and externalizing were also associated with any substance dependence (ORs = 1.09-1.18). The full model explained 6-13% of the variance in SUDs. Those in the top 10% of CERI and PGS had relative risk ratios of 3.86-8.04 for each SUD relative to the bottom 90%. Overall, the combined measures of clinical, environmental, and genetic risk demonstrated modest ability to distinguish between affected and unaffected individuals in young adulthood. PGS were significant but added little in addition to the clinical/environmental risk index. Results from our analysis demonstrate there is still considerable work to be done before tools such as these are ready for clinical applications.Peer reviewe
RF Helicon-based Inductive Plasma Thruster (IPT) Design for an Atmosphere-Breathing Electric Propulsion system (ABEP)
Challenging space missions include those at very low altitudes, where the atmosphere is source of aerodynamic drag on the spacecraft. To extend such missions lifetime, an efficient propulsion system is required. One solution is Atmosphere-Breathing Electric Propulsion (ABEP). It collects atmospheric particles to be used as propellant for an electric thruster. The system would minimize the requirement of limited propellant availability and can also be applied to any planet with atmosphere, enabling new mission at low altitude ranges for longer times. Challenging is also the presence of reactive chemical species, such as atomic oxygen in Earth orbit. Such species cause erosion of (not only) propulsion system components, i.e. acceleration grids, electrodes, and discharge channels of conventional EP systems. IRS is developing within the DISCOVERER project, an intake and a thruster for an ABEP system. The paper describes the design and implementation of the RF helicon-based inductive plasma thruster (IPT). This paper deals in particular with the design and implementation of a novel antenna called the birdcage antenna, a device well known in magnetic resonance imaging (MRI), and also lately employed for helicon-wave based plasma sources in fusion research. This is aided by the numerical tool XFdtdÂź. The IPT is based on RF electrodeless operation aided by an externally applied static magnetic field. The IPT is composed by an antenna, a discharge channel, a movable injector, and a solenoid. By changing the operational parameters along with the novel antenna design, the aim is to minimize losses in the RF circuit, and accelerate a quasi-neutral plasma plume. This is also to be aided by the formation of helicon waves within the plasma that are to improve the overall efficiency and achieve higher exhaust velocities. Finally, the designed IPT with a particular focus on the birdcage antenna design procedure is presented
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