794 research outputs found
Effect of boiling point rankings and feed locations on the applicability of reactive distillation to quaternary systems
Reactive distillation (RD) offers major benefits such as costs reduction and energy saving, but the understanding and design of RD processes usually demand complex tasks that include extensive studies and rigorous simulations. To reduce this complexity and the time required, this study applies a novel mapping method to quickly provide insights into the RD applicability to reversible quaternary systems (A + B β C + D). Generic cases are used to produce applicability graphs (i.e. plots of reflux ratio vs number of theoretical stages) and multiple RD column configurations. The systems are assumed to have ideal properties and fixed key parameters (i.e. relative volatilities and chemical equilibrium constants). This study focuses on quaternary reactions considering different boiling point rankings and feed locations. Using the mapping method, quick results are achievable regarding the preliminary economic ranking of RD processes, and the optimal feed locations with reduced energy requirement (i.e. lower reflux ratio). Ultimately, this study provides a much better understanding of the effect of boiling point orders and feed locations on the RD applicability and conceptual design, being a valuable tool in early techno-economic evaluations
ΠΠ½Π²Π΅ΡΡΠΈΡΡΠΉΠ½Π΅ ΠΊΡΠ΅Π΄ΠΈΡΡΠ²Π°Π½Π½Ρ ΠΏΠ΅ΡΠ΅ΡΠΎΠ±Π½ΠΈΡ ΠΏΡΠ΄ΠΏΡΠΈΡΠΌΡΡΠ² ΠΠΠ Π±Π°Π½ΠΊΡΠ²ΡΡΠΊΠΈΠΌΠΈ ΡΡΡΠ°Π½ΠΎΠ²Π°ΠΌΠΈ
ΠΠ΅ΡΠΎΡ ΡΡΠ°ΡΡΡ Ρ Π°Π½Π°Π»ΡΠ· Π΄ΠΈΠ½Π°ΠΌΡΠΊΠΈ ΡΠ½Π²Π΅ΡΡΠΈΡΡΠΉΠ½ΠΎΠ³ΠΎ ΠΊΡΠ΅Π΄ΠΈΡΡΠ²Π°Π½Π½Ρ Π±Π°Π½ΠΊΡΠ²ΡΡΠΊΠΈΠΌΠΈ ΡΡΡΠ°Π½ΠΎΠ²Π°ΠΌΠΈ ΠΏΠ΅ΡΠ΅ΡΠΎΠ±Π½ΠΈΡ
ΠΏΡΠ΄ΠΏΡΠΈΡΠΌΡΡΠ² Π°Π³ΡΠΎΠΏΡΠΎΠΌΠΈΡΠ»ΠΎΠ²ΠΎΠ³ΠΎ ΠΊΠΎΠΌΠΏΠ»Π΅ΠΊΡΡ. ΠΡΠ΄ ΡΠ°Ρ ΠΏΡΠΎΠ²Π΅Π΄Π΅Π½Π½Ρ Π΄ΠΎΡΠ»ΡΠ΄ΠΆΠ΅Π½Π½Ρ Π±ΡΠ»ΠΈ Π²ΠΈΠΊΠΎΡΠΈΡΡΠ°Π½Ρ Π°Π½Π°Π»ΡΡΠΈΡΠ½ΠΈΠΉ, ΡΡΠ°ΡΠΈΡΡΠΈΠΊΠΎ β Π΅ΠΊΠΎΠ½ΠΎΠΌΡΡΠ½ΠΈΠΉ, Π³ΡΠ°ΡΡΡΠ½ΠΈΠΉ, ΠΏΠΎΡΡΠ²Π½ΡΠ»ΡΠ½ΠΈΠΉ ΠΌΠ΅ΡΠΎΠ΄ΠΈ ΡΠ° ΠΌΠ΅ΡΠΎΠ΄ ΡΠΈΡΡΠ΅ΠΌΠ½ΠΎΠ³ΠΎ Π°Π½Π°Π»ΡΠ·Ρ
Dealing with care disruption in High and Intensive Care wards:From difficult patients to difficult situations
High and Intensive Care is a relatively new care model in Dutch mental health care for clinical admissions. One of the goals is to keep the admission short. For some patients, this goal is not realized, which results in a long-term admission. Often, this is experienced as a disruption. Disruptions in care processes are frequently defined in terms of patient characteristics. Yet, it may be that other factors play a role. The aim of this study is to gain better insight into the perceptions of care professionals of what is characteristic for disruptions at High and Intensive Care wards and how professionals can deal with these. Qualitative research was performed by means of semi-structured interviews and a focus group with professionals. Results show that a focus on patient characteristics is too narrow and that other factors also play an important role. These factors include challenges in the relation between professionals and the patient, a divided team, and a lack of collaboration with ambulatory care. In order to deal with these factors, professionals should invest in the relationship with the patient, identify destructive team processes early, and improve communication with ambulatory care. It is recommended to develop a monitoring tool that includes all these factors. Another recommendation is to organize structured reflection on dilemmas experienced in care. In conclusion, this study shows the importance of going beyond patient characteristics in order to better understand, identify, and deal with disruption at High and Intensive Care wards
Cytoskeletonβs Role in KIR2.1 Trafficking
Alteration of the inward rectifier current IK1, carried by KIR2.1 channels, affects action potential duration, impacts resting membrane stability and associates with cardiac arrhythmias. Congenital and acquired KIR2.1 malfunction frequently associates with aberrant ion channel trafficking. Cellular processes underlying trafficking are intertwined with cytoskeletal function. The extent to which the cytoskeleton is involved in KIR2.1 trafficking processes is unknown. We aimed to quantify the dependence of KIR2.1 trafficking on cytoskeleton function. GFP or photoconvertible Dendra2 tagged KIR2.1 constructs were transfected in HEK293 or HeLa cells. Photoconversion of the Dendra2 probe at the plasma membrane and subsequent live imaging of trafficking processes was performed by confocal laser-scanning microscopy. Time constant of green fluorescent recovery (Οg,s) represented recruitment of new KIR2.1 at the plasma membrane. Red fluorescent decay (Οr,s) represented internalization of photoconverted KIR2.1. Patch clamp electrophysiology was used to quantify IKIR2.1. Biochemical methods were used for cytoskeleton isolation and detection of KIR2.1 cytoskeleton interactions. Cytochalasin B (20 ΞΌM), Nocodazole (30 ΞΌM) and Dyngo-4a (10 nM) were used to modify the cytoskeleton. Chloroquine (10 ΞΌM, 24 h) was used to impair KIR2.1 breakdown. Cytochalasin B and Nocodazole, inhibitors of actin and tubulin filament formation respectively, strongly inhibited the recovery of green fluorescence at the plasma membrane suggestive for inhibition of KIR2.1 forward trafficking [Οg,s 13 Β± 2 vs. 131 Β± 31* and 160 Β± 40* min, for control, Cytochalasin B and Nocodazole, respectively (*p < 0.05 vs. control)]. Dyngo-4a, an inhibitor of dynamin motor proteins, strongly slowed the rate of photoconverted channel internalization, whereas Nocodazole and Cytochalasin B had less effect [Οr,s 20 Β± 2 vs. 87 Β± 14*, 60 Β± 16 and 64 Β± 20 min (*p < 0.05 vs. control)]. Cytochalasin B treatment (20 ΞΌM, 24 h) inhibited IKIR2.1. Chloroquine treatment (10 ΞΌM, 24 h) induced intracellular aggregation of KIR2.1 channels and enhanced interaction with the actin/intermediate filament system (103 Β± 90 fold; p < 0.05 vs. control). Functional actin and tubulin cytoskeleton systems are essential for forward trafficking of KIR2.1 channels, whereas initial backward trafficking relies on a functional dynamin system. Chronic disturbance of the actin system inhibits KIR2.1 currents. Internalized KIR2.1 channels become recruited to the cytoskeleton, presumably in lysosomes
Topography-driven alterations in endothelial cell phenotype and contact guidance
Bioengineering; Biophysics; Cell biology; Biomedical engineering; Regenerative medicine; Directional topography; Endothelial cells; Vascular-like networks; Contact guidance; Vascularizatio
Economic comparison of reactive distillation (RD) to a benchmark conventional flowsheet:Regions of RD applicability and trends in column design
A novel methodology for the techno-economic assessment of Reactive Distillation (RD) is presented. The developed methodology benchmarks reactive distillation (RD) to a conventional reactor + distillation train flowsheet (R+D) on a cost-optimized basis, with the optimization being performed on the process unit level (reactor sizing, number of stages, feed point(s)) and the internals level (reactive tray design). This methodology is applied to the ideal quaternary system A+BβC+D with the conventional boiling point order of TC < TA < TB < TD (Ξ±AD = 4, Ξ±BD = 2, Ξ±CD = 8). From this pool of data, a regime map of RD vs. R+D is established in which the attractive regions of either flowsheet option are identified in terms of the chemical reaction rate and chemical equilibrium. It is found that RD can arise as the cost optimal option for a large range of residence time requirements by virtue of overcoming the external recycle requirements of R+D. This is achieved through optimized reactive tray design. Contrary to conventional distillation design practices, it was found that the preferred use of bubble-cap trays over sieve trays to allow elevated weir heights and designing the column diameter below 80% of flooding become relevant design choices when accommodating high liquid holdup.</p
Neural correlates of egocentric and allocentric frames of reference combined with metric and non-metric spatial relations
Spatial relations (SRs: coordinate/metric vs categorical/non metric) and frames of reference (FoRs: egocentric/body vs allocentric/external element) represent the building blocks underlying any spatial representation. In the present 7-T fMRI study we have identified for the first time the neural correlates of the spatial representations emerging from the combination of the two dimensions. The direct comparison between the different spatial representations revealed a bilateral fronto-parietal network, mainly right sided, that was more involved in the egocentric categorical representations. A right fronto-parietal circuitry was specialized for egocentric coordinate representations. A bilateral occipital network was more involved in the allocentric categorical representations. Finally, a smaller part of this bilateral network (i.e. Calcarine Sulcus and Lingual Gyrus), along with the right Supramarginal and Inferior Frontal gyri, supported the allocentric coordinate representations. The fact that some areas were more involved in a spatial representation than in others reveals how our brain builds adaptive spatial representations in order to effectively react to specific environmental needs and task demands
Retinotopic Mapping of Categorical and Coordinate Spatial Relation Processing in Early Visual Cortex
Spatial relations are commonly divided in two global classes. Categorical relations concern abstract relations which define areas of spatial equivalence, whereas coordinate relations are metric and concern exact distances. Categorical and coordinate relation processing are thought to rely on at least partially separate neurocognitive mechanisms, as reflected by differential lateralization patterns, in particular in the parietal cortex. In this study we address this textbook principle from a new angle. We studied retinotopic activation in early visual cortex, as a reflection of attentional distribution, in a spatial working memory task with either a categorical or a coordinate instruction. Participants were asked to memorize a dot position, with regard to a central cross, and to indicate whether a subsequent dot position matched the first dot position, either categorically (opposite quadrant of the cross) or coordinately (same distance to the centre of the cross). BOLD responses across the retinotopic maps of V1, V2, and V3 indicate that the spatial distribution of cortical activity was different for categorical and coordinate instructions throughout the retention interval; a more local focus was found during categorical processing, whereas focus was more global for coordinate processing. This effect was strongest for V3, approached significance in V2 and was absent in V1. Furthermore, during stimulus presentation the two instructions led to different levels of activation in V3 during stimulus encoding; a stronger increase in activity was found for categorical processing. Together this is the first demonstration that instructions for specific types of spatial relations may yield distinct attentional patterns which are already reflected in activity early in the visual cortex
Real-world indoor mobility with simulated prosthetic vision:The beneο¬ts and feasibility of contour-based scene simpliο¬cation at diο¬erent phosphene resolutions
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246314.pdf (Publisherβs version ) (Open Access)Neuroprosthetic implants are a promising technology for restoring some form of vision in people with visual impairments via electrical neurostimulation in the visual pathway. Although an artificially generated prosthetic percept is relatively limited compared with normal vision, it may provide some elementary perception of the surroundings, re-enabling daily living functionality. For mobility in particular, various studies have investigated the benefits of visual neuroprosthetics in a simulated prosthetic vision paradigm with varying outcomes. The previous literature suggests that scene simplification via image processing, and particularly contour extraction, may potentially improve the mobility performance in a virtual environment. In the current simulation study with sighted participants, we explore both the theoretically attainable benefits of strict scene simplification in an indoor environment by controlling the environmental complexity, as well as the practically achieved improvement with a deep learning-based surface boundary detection implementation compared with traditional edge detection. A simulated electrode resolution of 26 x 26 was found to provide sufficient information for mobility in a simple environment. Our results suggest that, for a lower number of implanted electrodes, the removal of background textures and within-surface gradients may be beneficial in theory. However, the deep learning-based implementation for surface boundary detection did not improve mobility performance in the current study. Furthermore, our findings indicate that, for a greater number of electrodes, the removal of within-surface gradients and background textures may deteriorate, rather than improve, mobility. Therefore, finding a balanced amount of scene simplification requires a careful tradeoff between informativity and interpretability that may depend on the number of implanted electrodes.14 p
In response to βPrenatal screening of sialic acid storage disease and confirmation in cultured fibroblasts by LC-MS/MSβ by van den Bosch et al.
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