Starting jet flows in a three-dimensional channel with larynx-shaped constriction

A numerical model for the three-dimensional starting jet flow in a channel with a static larynx-shaped constriction is presented. Detailed resolution of this kind of jet flow is necessary in order to understand the complex coupling between flow and acoustics in the process of human phonation. The numerical model is based on the equation of continuity and the Navier-Stokes equations. The investigations are done with the open source CFD package OpenFOAM. Numerical simulations are performed for a square-sectioned channel geometry, which is constricted with a fixed shape conforming to the fully opened human glottis. Time-dependent inflow boundary conditions are applied in order to model transient glottal flow rates. The setup of the numerical simulations corresponds to the configuration of a model experiment in order to allow detailed validation. The numerical results are in good agreement with the experimental data, when the near-wall region in the glottal gap is adequately resolved by the numerical grid. The results illustrate the complex interactions between the jet flow and the surrounding vortices. © 2011 Elsevier Ltd

Digestibility of resistant starch type 3 is affected by crystal type, molecular weight and molecular weight distribution

Resistant starch type 3 (RS-3) holds great potential as a prebiotic by supporting gut microbiota following intestinal digestion. However the factors influencing the digestibility of RS-3 are largely unknown. This research aims to reveal how crystal type and molecular weight (distribution) of RS-3 influence its resistance. Narrow and polydisperse α-glucans of degree of polymerization (DP) 14–76, either obtained by enzymatic synthesis or debranching amylopectins from different sources, were crystallized in 12 different A- or B-type crystals and in vitro digested. Crystal type had the largest influence on resistance to digestion (A >>> B), followed by molecular weight (Mw) (high DP >> low DP) and Mw distribution (narrow disperse > polydisperse). B-type crystals escaping digestion changed in Mw and Mw distribution compared to that in the original B-type crystals, whereas A-type crystals were unchanged. This indicates that pancreatic α-amylase binds and acts differently to A- or B-type RS-3 crystals.</p

Type of intrinsic resistant starch type 3 determines in vitro fermentation by pooled adult faecal inoculum

Resistant starch (RS) results in relatively high health-beneficial butyrate levels upon fermentation by gut microbiota. We studied how physico-chemical characteristics of RS-3 influenced butyrate production during fermentation. Six highly resistant RS-3 substrates (intrinsic RS-3, 80-95 % RS) differing in chain length (DPn 16-76), Mw distribution (PI) and crystal type (A/B) were fermented in vitro by pooled adult faecal inoculum. All intrinsic RS-3 substrates were fermented to relatively high butyrate levels (acetate/butyrate ≤ 2.5), and especially fermentation of A-type RS-3 prepared from polydisperse α-1,4 glucans resulted in the highest relative butyrate amount produced (acetate/butyrate: 1). Analysis of the microbiota composition after fermentation revealed that intrinsic RS-3 stimulated primarily Lachnospiraceae, Bifidobacterium and Ruminococcus, but the relative abundances of these taxa differed slightly depending on the RS-3 physico-chemical characteristics. Especially intrinsic RS-3 of narrow disperse Mw distribution stimulated relatively more Ruminococcus. Selected RS fractions (polydisperse Mw distribution) obtained after pre-digestion were fermented to acetate and butyrate (ratio ≤ 1.8) and stimulated Lachnospiraceae and Bifidobacterium. This study indicates that especially the α-1,4 glucan Mw distribution dependent microstructure of RS-3 influences butyrate production and microbiota composition during RS-3 fermentation.</p

Vitaal Landelijk Gebied in kaart : Jaarboek 2009 Cluster Vitaal Landelijk Gebied

‘Vitaal Landelijk Gebied in kaart’. Dat is de titel en het thema van dit jaarboek. Niet alleen figuurlijk – een selectie van projecten die zijn uitgevoerd binnen het cluster – maar het vitaal landelijk gebied is ook letterlijk in kaart gebracht. Veel projecten zijn niet aan een bepaald gebied gebonden en gaan over Nederland als geheel. De kaarten visualiseren de projecten uitgevoerd in 2009 – en voor zover nog te achterhalen – projecten terug in de VLG-tijd tot 2005. Het was niet mogelijk alle projecten te presenteren. Themacoördinatoren hebben een selectie gemaakt. Per project leest u over de onderzoeksvraag, de relevantie van het onderzoek voor het beleid, wat het onderzoek heeft opgeleverd en wat er met de nieuwe kennis is gedaan

Anthropogenic Heat Flux Estimation from Space: Results of the first phase of the URBANFLUXES Project

H2020-Space project URBANFLUXES (URBan ANthrpogenic heat FLUX from Earth observation Satellites) investigates the potential of Copernicus Sentinels to retrieve anthropogenic heat flux, as a key component of the Urban Energy Budget (UEB). URBANFLUXES advances the current knowledge of the impacts of UEB fluxes on urban heat island and consequently on energy consumption in cities. This will lead to the development of tools and strategies to mitigate these effects, improving thermal comfort and energy efficiency. In URBANFLUXES, the anthropogenic heat flux is estimated as a residual of UEB. Therefore, the rest UEB components, namely, the net all-wave radiation, the net change in heat storage and the turbulent sensible and latent heat fluxes are independently estimated from Earth Observation (EO), whereas the advection term is included in the error of the anthropogenic heat flux estimation from the UEB closure. The project exploits Sentinels observations, which provide improved data quality, coverage and revisit times and increase the value of EO data for scientific work and future emerging applications. These observations can reveal novel scientific insights for the detection and monitoring of the spatial distribution of the urban energy budget fluxes in cities, thereby generating new EO opportunities. URBANFLUXES thus exploits the European capacity for space-borne observations to enable the development of operational services in the field of urban environmental monitoring and energy efficiency in cities. H2020-Space project URBANFLUXES (URBan ANthrpogenic heat FLUX from Earth observation Satellites)investigates the potential of Copernicus Sentinels to retrieve anthropogenic heat flux, as a key component of the UrbanEnergy Budget (UEB). URBANFLUXES advances the current knowledge of the impacts of UEB fluxes on urban heatisland and consequently on energy consumption in cities. This will lead to the development of tools and strategies tomitigate these effects, improving thermal comfort and energy efficiency. In URBANFLUXES, the anthropogenic heatflux is estimated as a residual of UEB. Therefore, the rest UEB components, namely, the net all-wave radiation, the netchange in heat storage and the turbulent sensible and latent heat fluxes are independently estimated from EarthObservation (EO), whereas the advection term is included in the error of the anthropogenic heat flux estimation from theUEB closure. The project exploits Sentinels observations, which provide improved data quality, coverage and revisittimes and increase the value of EO data for scientific work and future emerging applications. These observations canreveal novel scientific insights for the detection and monitoring of the spatial distribution of the urban energy budgetfluxes in cities, thereby generating new EO opportunities. URBANFLUXES thus exploits the European capacity forspace-borne observations to enable the development of operational services in the field of urban environmentalmonitoring and energy efficiency in cities

Value of neuropsychological tests to identify patients with depressive symptoms on the Alzheimer's disease continuum

BACKGROUND: Depressive symptoms often co-occur with Alzheimer's disease (AD) and can impact neuropsychological test results. In early stages of AD, disentangling cognitive impairments due to depression from those due to neurodegeneration often poses a challenge. OBJECTIVE: We aimed to identify neuropsychological tests able to detect AD-typical pathology while taking into account varying degrees of depressive symptoms. METHODS: A battery of neuropsychological tests (CERAD-NP) and the Geriatric Depression Scale (GDS) were assessed, and cerebrospinal fluid (CSF) biomarkers were obtained. After stratifying patients into CSF positive or negative and into low, moderate, or high GDS score groups, sensitivity and specificity and area under the curve (AUC) were calculated for each subtest. RESULTS: 497 participants were included in the analyses. In patients with low GDS scores (≤10), the highest AUC (0.72) was achieved by Mini-Mental State Examination, followed by Constructional Praxis Recall and Wordlist Total Recall (AUC = 0.714, both). In patients with moderate (11-20) and high (≥21) GDS scores, Trail Making Test-B (TMT-B) revealed the highest AUCs with 0.77 and 0.82, respectively. CONCLUSION: Neuropsychological tests showing AD-typical pathology in participants with low GDS scores are in-line with previous results. In patients with higher GDS scores, TMT-B showed the best discrimination. This indicates the need to focus on executive function rather than on memory task results in depressed patients to explore a risk for AD

Launching the Delta Alliance: Content report phase 3

Delta Alliance is an international knowledge-driven network organisation. Its mission is to improve the resilience of deltas through more integrated and effective efforts, building on scientific research and knowledge exchange. It aims at disclosure of knowledge for application by a wide audience of end-users from the knowledge institutions, public partners and private sector, as well as to identification of upcoming research agenda