401 research outputs found
Phase separation phenomena during the formation of asymmetric membranes
The formation of membranes from two systems has been studied. In the system polyurethane-dimethylformamide-water, the mechanism for the formation of the sponge-like structure proves to be a liquid-liquid phase separation with nucleation and growth of the diluted phase. This mechanism has been confirmed for the system modified polystyrene-polyisoprene-polystyrene/o-dichlorobenzene/(methanol-water). Crystallization and gelation is discussed. The membranes prepared showed hyperfiltration activity. The mechanism proposed here is believed to be valid for other systems, too
flavour tagging using charm decays at the LHCb experiment
An algorithm is described for tagging the flavour content at production of
neutral mesons in the LHCb experiment. The algorithm exploits the
correlation of the flavour of a meson with the charge of a reconstructed
secondary charm hadron from the decay of the other hadron produced in the
proton-proton collision. Charm hadron candidates are identified in a number of
fully or partially reconstructed Cabibbo-favoured decay modes. The algorithm is
calibrated on the self-tagged decay modes and using of data collected by the LHCb
experiment at centre-of-mass energies of and
. Its tagging power on these samples of
decays is .Comment: All figures and tables, along with any supplementary material and
additional information, are available at
http://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-027.htm
Sedimentology, stratigraphic context, and implications of Miocene intrashelf bottomset deposits, offshore New Jersey
Drilling of intrashelf Miocene clinothems onshore and offshore New Jersey has provided better understanding of their topset and foreset deposits, but the sedimentology and stratigraphy of their bottomset deposits have not been documented in detail. Three coreholes (Sites M27–M29), collected during Integrated Ocean Drilling Program (IODP) Expedition 313, intersect multiple bottomset deposits, and their analysis helps to refine sequence stratigraphic interpretations and process response models for intrashelf clinothems. At Site M29, the most downdip location, chronostratigraphically well-constrained bottomset deposits follow a repeated stratigraphic motif. Coarse-grained glauconitic quartz sand packages abruptly overlie deeply burrowed surfaces. Typically, these packages coarsen then fine upwards and pass upward into bioturbated siltstones. These coarse sand beds are amalgamated and poorly sorted and contain thin-walled shells, benthic foraminifera, and extrabasinal clasts, consistent with an interpretation of debrites. The sedimentology and mounded seismic character of these packages support interpretation as debrite-dominated lobe complexes. Farther updip, at Site M28, the same chronostratigraphic units are amalgamated, with the absence of bioturbated silts pointing to more erosion in proximal locations. Graded sandstones and dune-scale cross-bedding in the younger sequences in Site M28 indicate deposition from turbidity currents and channelization. The sharp base of each package is interpreted as a sequence boundary, with a period of erosion and sediment bypass evidenced by the burrowed surface, and the coarse-grained debritic and turbiditic deposits representing the lowstand systems tract. The overlying fine-grained deposits are interpreted as the combined transgressive and highstand systems tract deposits and contain the deepwater equivalent of the maximum flooding surface. The variety in thickness and grain-size trends in the coarse-grained bottomset packages point to an autogenic control, through compensational stacking of lobes and lobe complexes. However, the large-scale stratigraphic organization of the bottomset deposits and the coarse-grained immature extrabasinal and reworked glauconitic detritus point to external controls, likely a combination of relative sea-level fall and waxing-and-waning cycles of sediment supply. This study demonstrates that large amounts of sediment gravity-flow deposits can be generated in relatively shallow (~100–200 m deep) and low-gradient (~1°–4°) clinothems that prograded across a deep continental shelf. This physiography likely led to the dominance of debris flow deposits due to the short transport distance limiting transformation to low-concentration turbidity currents
Allied rehabilitation using caregiver-mediated exercises combined with telerehabilitation for stroke (ARMed4Stroke):A randomised controlled trial
Objective: To assess the added value of caregiver-mediated exercises combined with telerehabilitation in addition to usual care compared to usual care alone on the self-reported mobility outcome after subacute stroke. Design: Multicentre, observer-blinded, parallel randomised controlled trial. An off-site researcher allocated treatments using minimisation. Setting: Four rehabilitation centres in the Netherlands. Participants: Forty-one patient–caregiver dyads within 3 months poststroke. Intervention: Eight-week blended care program with caregiver-mediated mobility exercises for 2.5 h per week supported by telerehabilitation and four face-to-face sessions in addition to usual care. Main measures: Self-reported mobility domain of the Stroke Impact Scale postintervention. Secondary outcomes were functional outcome, dyads’ psychosocial wellbeing, care transition to the community postintervention and after 6 months. Results: Forty-one dyads (21 intervention, 20 control) were randomised, and 37 (N = 18; N = 19) were analysed following intention-to-treat. The Stroke Impact Scale mobility was not significantly different between groups postintervention (B 0.8, 95% CI –6.8–8.5, p = 0.826). The secondary outcomes, namely, (a) caregivers’ quality of life postintervention (p = 0.013), (b) caregivers’ symptoms of depression postintervention (p = 0.025), and (c) independence in leisurely activities at 6 months (p = 0.024), showed significant benefits in favour of caregiver-mediated exercises with telerehabilitation. A significant difference favouring controls was found in self-reported muscle strength at 6 months (p = 0.002). Conclusions: Caregiver-mediated exercises combined with telerehabilitation yielded no differential effect on our primary outcome self-reported mobility. Although the trial is underpowered, current findings are in line with previous trials. Future studies should further explore beneficial effects of caregiver involvement in stroke rehabilitation targeting psychosocial wellbeing.</p
A burst detection from FRB 20240209A at 1.3 GHz using the Westerbork-RT1 25-m telescope
We report on the detection of a fast radio burst (FRB) originating from the CHIME/FRB-discovered source FRB 20240209A (ATels #16670, #16682, #16687). We detected the burst using the 25-m Westerbork RT-1 telescope observing at a central frequency of 1.27 GHz (L-band) with a 128-MHz bandwidth (see Kirsten et al. 2024 for more details on the observational setup). This detection marks the highest frequency at which the source has been observed, demonstrating that the source is active and detectable at L-band
Comparing models of an exoplanet-earth to earthshine observations
Polarimetry is widely becoming recognized as a powerful technique for enhancing the contrast between a star and an exoplanet, and thus improving upon the direct detection of exoplanets. The real power of polarimetry, however, is in its ability to characterize the physical properties of these worlds. This is because the state of the polarization of the light from the planet is very sensitive to the composition and structure of the planetary atmosphere and surface, being affected by properties such as the mixing ratios of atmospheric absorbing gases, cloud optical thickness, cloud top pressure, cloud particle size, and surface albedo. Various groups have theoretically studied the optical linear polarimetric signals of Earth-like exoplanets as functions of both orbital phase and wavelength. This project aims to validate the accuracy of these theoretical models against the only known observations of an Earth-like planet thus far: Earthshine. Using atmospheric and surface data taken by the MODIS instrument aboard the Terra and Aqua satellites, as well as surface albedo spectra from the EcoStress Spectral Library, we created a detailed model of the Earth. Then, using this model data as input for three separate radiative transfer algorithms, we generate the flux and linear polarization spectra for the model exoplanet-Earth from the optical to near-infrared wavelengths. We compare the results from all three codes to each other and to observational linear spectropolarimetric data of the Earthshine obtained by a member of our group. We identify similarities and potential pitfalls between these codes in an effort to improve our future characterizations of Earth-like exoplanets.Stars and planetary system
Earth-as-an-exoplanet: comparing earthshine observations to models of an exo-Earth
Traditional methods of exoplanet characterization that only make use of emitted or reflected flux lack the ability to fully distinguish between different physical features of the target, such as cloud layers, hazes, or surface features. Polarimetry, however, is a powerful, more sensitive technique that has this ability, as it measures light as a vector (by the orientation of the electric field) rather than a scalar intensity. It is therefore extremely sensitive to the composition and structure of the planetary atmosphere and surface, being affected by properties such as the mixing ratios of atmospheric absorbing gases, cloud optical thickness, cloud top pressure, cloud particle size, and surface albedo. Various groups have theoretically studied the optical linear polarimetric signals of Earth-like exoplanets as functions of both orbital phase and wavelength. With this project we assess the accuracy of these theoretical models against observations of the Earthshine, the only known observations of an Earth-like planet thus far. Using data of the atmosphere and surface taken by the MODIS instrument aboard the Terra and Aqua satellites, as well as surface reflectance spectra from the JPL EcoStress Spectral Library, we created a gridded model of the Earth. Then, using this model data as input for three separate radiative transfer algorithms, we generate the flux and linear polarization spectra for the model exoplanet-Earth across the optical to near-infrared wavelengths. We compare the results from all three codes to each other and to the observational linear spectropolarimetric data of the Earthshine obtained by a member of our group. We identify similarities and potential pitfalls between the codes, and make necessary adjustments to them, in an effort to improve our future characterizations of terrestrial exoplanets.Stars and planetary system
A burst detection from FRB 20240209A at 1.3 GHz using the Westerbork-RT1 25-m telescope
We report on the detection of a fast radio burst (FRB) originating from the CHIME/FRB-discovered source FRB 20240209A (ATels #16670, #16682, #16687). We detected the burst using the 25-m Westerbork RT-1 telescope observing at a central frequency of 1.27 GHz (L-band) with a 128-MHz bandwidth (see Kirsten et al. 2024 for more details on the observational setup). This detection marks the highest frequency at which the source has been observed, demonstrating that the source is active and detectable at L-band
Measurement of CP observables in B± → D(⁎)K± and B± → D(⁎)π± decays
Measurements of CP observables in B ± →D (⁎) K ± and B ± →D (⁎) π ± decays are presented, where D (⁎) indicates a neutral D or D ⁎ meson that is an admixture of D (⁎)0 and D¯ (⁎)0 states. Decays of the D ⁎ meson to the Dπ 0 and Dγ final states are partially reconstructed without inclusion of the neutral pion or photon, resulting in distinctive shapes in the B candidate invariant mass distribution. Decays of the D meson are fully reconstructed in the K ± π ∓ , K + K − and π + π − final states. The analysis uses a sample of charged B mesons produced in pp collisions collected by the LHCb experiment, corresponding to an integrated luminosity of 2.0, 1.0 and 2.0 fb −1 taken at centre-of-mass energies of s=7, 8 and 13 TeV, respectively. The study of B ± →D ⁎ K ± and B ± →D ⁎ π ± decays using a partial reconstruction method is the first of its kind, while the measurement of B ± →DK ± and B ± →Dπ ± decays is an update of previous LHCb measurements. The B ± →DK ± results are the most precise to date
Liposomal prednisolone promotes macrophage lipotoxicity in experimental atherosclerosis
Atherosclerosis is a lipid-driven inflammatory disease, for which nanomedicinal interventions are under evaluation. Previously, we showed that liposomal nanoparticles loaded with prednisolone (LN-PLP) accumulated in plaque macrophages, however, induced proatherogenic effects in patients. Here, we confirmed in low-density lipoprotein receptor knockout (LDLr−/−) mice that LN-PLP accumulates in plaque macrophages. Next, we found that LN-PLP infusions at 10 mg/kg for 2 weeks enhanced monocyte recruitment to plaques. In follow up, after 6 weeks of LN-PLP exposure we observed (i) increased macrophage content, (ii) more advanced plaque stages, and (iii) larger necrotic core sizes. Finally, in vitro studies showed that macrophages become lipotoxic after LN-PLP exposure, exemplified by enhanced lipid loading, ER stress and apoptosis. These findings indicate that liposomal prednisolone may paradoxically accelerate atherosclerosis by promoting macrophage lipotoxicity. Hence, future (nanomedicinal) drug development studies are challenged by the multifactorial nature of atherosclerotic inflammation
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