1,038 research outputs found
Does low-energy sweetener consumption affect energy intake and body weight? A systematic review, including meta-analyses, of the evidence from human and animal studies
By reducing energy density, low-energy sweeteners (LES) might be expected to reduce energy intake (EI) and body weight (BW). To assess the totality of the evidence testing the null hypothesis that LES exposure (versus sugars or unsweetened alternatives) has no effect on EI or BW, we conducted a systematic review of relevant studies in animals and humans consuming LES with ad libitum access to food energy. In 62 of 90 animal studies exposure to LES did not affect or decreased BW. Of 28 reporting increased BW, 19 compared LES with glucose exposure using a specific ‘learning’ paradigm. Twelve prospective cohort studies in humans reported inconsistent associations between LES use and Body Mass Index (-0.002 kg/m2/year, 95%CI -0.009 to 0.005). Meta-analysis of short- term randomized controlled trials (RCTs, 129 comparisons) showed reduced total EI for LES- versus sugar-sweetened food or beverage consumption before an ad libitum meal (-94 kcal, 95%CI -122 to -66), with no difference versus water (-2 kcal, 95%CI -30 to 26). This was consistent with EI results from sustained intervention RCTs (10 comparisons). Meta-analysis of sustained intervention RCTs (4 weeks to 40 months) showed that consumption of LES versus sugar led to relatively reduced BW (nine comparisons; -1.35 kg, 95%CI –2.28 to - 0.42), and a similar relative reduction in BW versus water (three comparisons; -1.24 kg, 95%CI –2.22 to -0.26). Most animal studies did not mimic LES consumption by humans, and reverse causation may influence the results of prospective cohort studies. The preponderance of evidence from all human RCTs indicates that LES do not increase EI or BW, whether compared with caloric or non-caloric (e.g., water) control conditions. Overall, the balance of evidence indicates that use of LES in place of sugar, in children and adults, leads to reduced EI and BW, and possibly also when compared with water
Are we training our novices towards quality 2D profiles for 3D models?
In the history-based, feature-based, parametric CAD approach, 2D profile sketches are
the basis for 3D models. Fully-constraining profiles is mandatory to create robust profiles. At present, neither CAD applications nor Model Quality Testing Tools usually
check whether 2D profiles contain redundant constraints. Besides, our experience
shows that novices tend to introduce redundant constraints. We hypothesize that 2D
profiles over-constrained with redundant relations are more difficult to edit than those
that avoid redundancies. In the present work―and as a first step to demonstrate this
hypothesis―an experiment was conducted. Students of the subject “Graphics engineering” were taught on the creation of constrained 2D profiles. Then, they were asked two
questions. On the one hand, novices had to identify and reason whether a simple given
profile was fully-constrained, over-constrained or under-constrained. On the other
hand, they had to identify and point out the types of the constraints. The results showed
that in spite that novices received a specific training, roughly half of them failed to say
if the 2D profile sketch was fully-constrained and which type of constraints it contained.
Furthermore, the results of the second question revealed that more than the half of students did not recognize perpendicularity as a geometric constraint. As future work, we
will try to demonstrate whether a reinforced training through simple exercises and a
quick and effective feedback, will allow novices to improve the identification and removal of redundant 2D constraints when drawing 2D profile sketches (thus helping to
produce robust profiles)
Esgrafiados barrocos en la Barcelona medieval
La Barcelona esgrafiada del siglo dieciocho es una ciudad artesanal que se convertirá en poco tiempo en una ciudad preindustrial. Es en este tiempo de unos 100 años cuando se crearán magníficas fachadas vestidas con hermosas decoraciones de iconología renacentista que acabarán generando un singular barroco catalán de influencias francesas e italianas. Hasta finales del XVIII coexisten en Barcelona diferentes decoraciones de esgrafiados, pintados o policromados al fresco o al seco, tanto encintados, como con puntas de diamante, plafones esgrafiados, escenografías arquitectónicas, escenas bucólicas, tapizados, todos generalmente realizados mediante el uso de plantillas (para sistematización del trabajo) y policromados, tanto al fresco como al seco, con pigmentos minerales
AI-based Agents for Automated Robotic Endovascular Guidewire Manipulation
Endovascular guidewire manipulation is essential for minimally-invasive
clinical applications (Percutaneous Coronary Intervention (PCI), Mechanical
thrombectomy techniques for acute ischemic stroke (AIS), or Transjugular
intrahepatic portosystemic shunt (TIPS)). All procedures commonly require 3D
vessel geometries from 3D CTA (Computed Tomography Angiography) images. During
these procedures, the clinician generally places a guiding catheter in the
ostium of the relevant vessel and then manipulates a wire through the catheter
and across the blockage. The clinician only uses X-ray fluoroscopy
intermittently to visualize and guide the catheter, guidewire, and other
devices. However, clinicians still passively control guidewires/catheters by
relying on limited indirect observation (i.e., 2D partial view of devices, and
intermittent updates due to radiation limit) from X-ray fluoroscopy. Modeling
and controlling the guidewire manipulation in coronary vessels remains
challenging because of the complicated interaction between guidewire motions
with different physical properties (i.e., loads, coating) and vessel geometries
with lumen conditions resulting in a highly non-linear system. This paper
introduces a scalable learning pipeline to train AI-based agent models toward
automated endovascular predictive device controls. First, we create a scalable
environment by pre-processing 3D CTA images, providing patient-specific 3D
vessel geometry and the centerline of the coronary. Next, we apply a large
quantity of randomly generated motion sequences from the proximal end to
generate wire states associated with each environment using a physics-based
device simulator. Then, we reformulate the control problem to a
sequence-to-sequence learning problem, in which we use a Transformer-based
model, trained to handle non-linear sequential forward/inverse transition
functions
Nanocomposites based on poly(glycerol sebacate) with silica nanoparticles with potential application in dental tissue engineering
"This is an Accepted Manuscript of an article published by Taylor & Francis inInternational Journal of Polymeric Materials and Polymeric Biomaterials on AUG 08 2020, available online: https://www.tandfonline.com/doi/full/10.1080/00914037.2019.1616197"[EN] Nanocomposites based on poly(glycerol sebacate) with silica nanoparticles were synthesized to explore their potential use in the biomedical field. The nanoparticles were two distinct polyhedral oligomeric silsesquioxanes (POSS), both used at 5% wt/wt concentration, specifically methacrylisobutyl POSS and methacryl POSS. These materials were investigated for their possible application as coatings as well as with regenerative purposes in dental engineering, and their viability for this application was assessed. Thus, pure PGS and nanohybrids thereof were obtained as scaffolds (that is, porous structures, designed with regenerative purposes) and as films (intended for coatings and to be used as controls).The authors acknowledge Dr. Kirsten Techmer from Geoscience Center of the Georg-August-University Gottingen for performing the EDX-SEM analysis, the assistance and advice of the Julich Center for Neutron Science (JCNS) and Institute for Complex Systems (ICS), Forschungszentrum Julich GmbH (Germany), and the Electron Microscopy Service of the Universitat Politecnica de Valencia (Spain). This work was partially funded by the Spanish Ministerio de Economía y Competitividad through DPI2015-65401-C3-2-R project and by the German Research Foundation [DFG/MWK INST 1525/39-1 FUGG]. A.V.-Ll. acknowledges the support of the Generalitat Valenciana, Conselleria de Educación, Investigación, Cultura y Deporte through project AEST/2018/014.Tallá Ferrer, C.; Vilariño, G.; Rizk, M.; Sydow, H.; Vallés Lluch, A. (2020). Nanocomposites based on poly(glycerol sebacate) with silica nanoparticles with potential application in dental tissue engineering. International Journal of Polymeric Materials. 69(12):761-772. https://doi.org/10.1080/00914037.2019.1616197S7617726912Wang, Y., Ameer, G. A., Sheppard, B. J., & Langer, R. (2002). A tough biodegradable elastomer. Nature Biotechnology, 20(6), 602-606. doi:10.1038/nbt0602-602Loh, X. J., Abdul Karim, A., & Owh, C. (2015). Poly(glycerol sebacate) biomaterial: synthesis and biomedical applications. Journal of Materials Chemistry B, 3(39), 7641-7652. doi:10.1039/c5tb01048aRai, R., Tallawi, M., Grigore, A., & Boccaccini, A. R. (2012). Synthesis, properties and biomedical applications of poly(glycerol sebacate) (PGS): A review. 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Correlating synthesis parameters with physicochemical properties of poly(glycerol sebacate). European Polymer Journal, 87, 406-419. doi:10.1016/j.eurpolymj.2017.01.001Gao, J., Crapo, P. M., & Wang, Y. (2006). Macroporous Elastomeric Scaffolds with Extensive Micropores for Soft Tissue Engineering. Tissue Engineering, 12(4), 917-925. doi:10.1089/ten.2006.12.917Klimek, J., Hellwig, E., & Ahrens, G. (1982). Fluoride Taken Up by Plaque, by the Underlying Enamel and by Clean Enamel from Three Fluoride Compounds in vitro. Caries Research, 16(2), 156-161. doi:10.1159/000260592Zhao, X., Wu, Y., Du, Y., Chen, X., Lei, B., Xue, Y., & Ma, P. X. (2015). A highly bioactive and biodegradable poly(glycerol sebacate)–silica glass hybrid elastomer with tailored mechanical properties for bone tissue regeneration. Journal of Materials Chemistry B, 3(16), 3222-3233. doi:10.1039/c4tb01693aWu, Y., Shi, R., Chen, D., Zhang, L., & Tian, W. (2011). Nanosilica filled poly(glycerol-sebacate-citrate) elastomers with improved mechanical properties, adjustable degradability, and better biocompatibility. Journal of Applied Polymer Science, 123(3), 1612-1620. doi:10.1002/app.34556Liang, S.-L., Cook, W. D., Thouas, G. A., & Chen, Q.-Z. (2010). The mechanical characteristics and in vitro biocompatibility of poly(glycerol sebacate)-Bioglass® elastomeric composites. Biomaterials, 31(33), 8516-8529. doi:10.1016/j.biomaterials.2010.07.105Kokubo, T., & Takadama, H. (2006). How useful is SBF in predicting in vivo bone bioactivity? Biomaterials, 27(15), 2907-2915. doi:10.1016/j.biomaterials.2006.01.017Wahab, M. A., Kim, I., & Ha, C.-S. (2003). Microstructure and properties of polyimide/poly(vinylsilsesquioxane) hybrid composite films. Polymer, 44(16), 4705-4713. doi:10.1016/s0032-3861(03)00429-4Yan Song, X., Ping Geng, H., & Li, Q. F. (2006). 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Wiley Encyclopedia of Biomedical Engineering. doi:10.1002/9780471740360.ebs140
Reliability of Single-Use PEEP-Valves Attached to Self-Inflating Bags during Manual Ventilation of Neonates – An In Vitro Study
Introduction International resuscitation guidelines suggest to use positive
end-expiratory pressure (PEEP) during manual ventilation of neonates. Aim of
our study was to test the reliability of self-inflating bags (SIB) with
single-use PEEP valves regarding PEEP delivery and the effect of different
peak inflation pressures (PIP) and ventilation rates (VR) on the delivered
PEEP. Methods Ten new single-use PEEP valves from 5 manufacturers were tested
by ventilating an intubated 1kg neonatal manikin containing a lung model with
a SIB that was actuated by an electromechanical plunger device. Standard
settings: PIP 20cmH2O, VR 60/min, flow 8L/min. PEEP settings of 5 and 10cmH2O
were studied. A second test was conducted with settings of PIP 40cmH2O and VR
40/min. The delivered PEEP was measured by a respiratory function monitor
(CO2SMO+). Results Valves from one manufacturer delivered no relevant PEEP and
were excluded. The remaining valves showed a continuous decay of the delivered
pressure during expiration. The median (25th and 75th percentile) delivered
PEEP with standard settings was 3.4(2.7–3.8)cmH2O when set to 5cmH2O and
6.1(4.9–7.1)cmH2O when set to 10cmH2O. Increasing the PIP from 20 to 40 cmH2O
led to a median (25th and 75th percentile) decrease in PEEP to
2.3(1.8–2.7)cmH2O and 4.3(3.2–4.8)cmH2O; changing VR from 60 to 40/min led to
a PEEP decrease to 2.8(2.1–3.3)cmH2O and 5.0(3.5–6.2)cmH2O for both PEEP
settings. Conclusion Single-use PEEP valves do not reliably deliver the set
PEEP. PIP and VR have an effect on the delivered PEEP. Operators should be
aware of these limitations when manually ventilating neonates
Channeled polymeric scaffolds with polypeptide gel filling for lengthwise guidance of neural cells
CNS damages are often irreversible since neurons of the central nervous system are unable to regenerate after an injury. As a new strategy within the nervous system tissue engineering, multifunctional systems based on two different biomaterials to support axonal guidance in damaged connective tracts have been developed herein. These systems are composed of a channeled scaffold made of ethyl acrylate and hydroxyethyl acrylate copolymer, P(EA-co-HEA), with parallel tubular micropores, combined with an injectable and in situ gelable self-assembling polypeptide (RAD16-I) as pores filler. The polymer scaffold is intended to provide a three-dimensional context for axon growth; subsequently, its morphology and physicochemical parameters have been determined by scanning electron microscopy, density measurements and compression tests. Besides, the hydrogel acts as a cell-friendly nanoenvironment while it creates a gradient of bioactive molecules (nerve growth factor, NGF) along the scaffolds channels; the chemotactic effect of NGF has been evaluated by a quantitative ELISA assay. These multifunctional systems have shown ability to keep circulating NGF, as well as proper short-term in vitro biological response with glial cells and neural progenitors.The authors acknowledge funding through the Spanish Ministerio de Ciencia e Innovacion (MAT2011-28791-C03-02 and -03). Dr. J.M. Garcia Verdugo (Department of Comparative Neurobiology, Cavanilles Institute of Biodiversity and Evolutive Biology, Universitat de Valencia) is thanked for kindly providing the cells employed in this work.Conejero García, Á.; Vilarino-Feltrer, G.; Martínez Ramos, C.; Monleón Pradas, M.; Vallés Lluch, A. (2015). Channeled polymeric scaffolds with polypeptide gel filling for lengthwise guidance of neural cells. European Polymer Journal. 70:331-341. doi:10.1016/j.eurpolymj.2015.07.033S3313417
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