Qualitative Flow Research Articles

A-354 Evaluating Emergent POC Technology for Sickle Cell Testing in Resource Limited Settings

Abstract Background Sickle cell disease (SCD) represents a collection of inherited hematological disorders characterized by abnormal sickle-shaped erythrocytes resulting in an increased risk of morbidity and mortality. SCD represents a significant global health burden, affecting more than 300,000 newborns per year. Most of these births occur in resource limited areas, including sub-Saharan Africa, where the mortality rate before the age of five is estimated to be as high as 50-80% and the existing infrastructure and resources cannot support most current and robust methods that offer hemoglobin variant detection and quantification for the diagnosis and monitoring of SCD. While newborn screening programs (NBS) to identify individuals affected with SCD have demonstrated efficacy in reducing morbidity and early mortality, NBS programs are limited outside of the US and Europe and face many practical challenges for universal implementation in a resource limited setting. The need for inexpensive and reliable hemoglobin variant detection and quantification at the Point of Care is essential to the diagnosis and management of SCD in resource limited settings with a high prevalence of SCD, and the expansion of NBS programs. This study aims to evaluate an inexpensive testing strategy using two methodologies for POC screening and confirmation of SCD that could be supported in a low resource setting. Methods The two-step testing strategy for evaluation of POC testing for hemoglobin variant detection and quantification included testing residual specimens from normal and known sickle cell patients by first screening with the HemoTypeSC, a qualitative lateral flow immunoassay (LFIA) that has improved sensitivity and specificity from other available LFIA methodologies given the use of monoclonal antibodies for the detection of hemoglobin variants. Confirmatory testing and quantification of hemoglobin variants was accomplished with the use of the Gazelle POC test a miniaturized chip-based cellulose acetate electrophoresis device capable of identification and quantification of normal and variant hemoglobin. Statistical evaluation of device performance and clinical agreement between the device and known disease status was achieved in EP evaluator. Results The two-tier testing strategy demonstrated effective and inexpensive mechanism for SCD screening and confirmation. Overall, the HemoTypeSC and Gazelle demonstrated 100% qualitative agreement between methods, with the total cost of the two-tiered testing strategy estimated at under $6 per sample. Conclusions In conclusion, the two-tiered approach using the HemoTypeSC and Gazelle yielded a practical and cost-effective strategy for screening and confirmation of hemoglobin variants for the detection and monitoring of SCD. Both the strip and chip-based methodologies provide rapid results, are accessible at the point-of-care, and require minimal sample volume, a feature ideal for use in a pediatric population in low resource settings. Overall, these methods show promise for the use and expansion of NBS programs to improve public health initiatives for the diagnosis of SCD.

Kidney Blood Flow and Renin-Angiotensin-Aldosterone System Measurements Associated With Kidney and Cardiovascular Dysfunction in Pediatric Shock.

Pediatric acute kidney injury (AKI) is a prevalent and morbid complication of shock. Its pathogenesis and early identification remain elusive. We aim to determine whether renal blood flow (RBF) measurements by point-of-care ultrasound (POCUS) and renin-angiotensin-aldosterone system (RAAS) hormones in pediatric shock associate with vasoactive requirements and AKI. This is a single-center prospective, noninterventional observational cohort study in one tertiary PICU in North American from 2020 to 2022 that enrolled children younger than 18 years with shock without preexisting end-stage renal disease. RBF was measured by POCUS on hospital days 1 and 3 and plasma RAAS hormone levels were measured on day 1. The primary outcome was the presence of AKI by Kidney Disease Improving Global Outcomes criteria at first ultrasound with key secondary outcomes of creatinine, blood urea nitrogen (BUN), Vasoactive-Inotrope Score (VIS), and norepinephrine equivalent dosing (NED) 48 hours after first ultrasound. Fifty patients were recruited (20 with AKI, mean age 10.5 yr, 48% female). POCUS RBF showed lower qualitative blood flow (power Doppler ultrasound [PDU] score) and higher regional vascular resistance (renal resistive index [RRI]) in children with AKI (p = 0.017 and p = 0.0007). Renin and aldosterone levels were higher in the AKI cohort (p = 0.003 and p = 0.007). Admission RRI and PDU associated with higher day 3 VIS and NED after adjusting for age, day 1 VIS, and RAAS hormones. Admission renin associated with higher day 3 creatinine and BUN after adjusting for age, day 1 VIS, and the ultrasound parameters. In pediatric shock, kidney blood flow was abnormal and renin and aldosterone were elevated in those with AKI. Kidney blood flow abnormalities are independently associated with future cardiovascular dysfunction; renin elevations are independently associated with future kidney dysfunction. Kidney blood flow by POCUS may identify children who will have persistent as opposed to resolving AKI. RAAS perturbations may drive AKI in pediatric shock.

Experimental observations of the onset of unsteadiness for buoyant airflow along smooth and rough vertical isothermal walls

ABSTRACT The buoyant airflow along a vertical isothermal wall, under conditions close to transitional, is studied. The schlieren technique and miniature thermocouples are employed for qualitative (flow unsteadiness) and quantitative (heat transfer coefficient and local air temperature) observations. For the smooth surface, the phenomena are found to be sensitive to the enclosure configuration surrounding the plate. Roughening the heated surface with staggered rib segments of proper dimensions leads to increased heat transfer, ascribed to the onset of unsteadiness close to the segments’ edges, together with a better redistribution of the flow thanks to a favorable hydrodynamic interaction between fluid and protrusions.

Feature-based deformation for flow visualization

We present an approach that supports the analysis of flow dynamics in the neighborhood of curved line-type features, such as vortex core lines, attachment lines, and trajectories. We achieve this with continuous deformation to the flow field to straighten such features. This provides “deformed frames of reference”, within which qualitative flow dynamics are better observable with respect to the feature. Our approach operates at interactive rates on graphics hardware, and supports exploration of large and complex datasets by continuously navigating the additional degree of freedom of deformation. We demonstrate the properties and the utility of our approach using synthetic and simulated flow fields, with a focus on the application to vortex core lines.Graphical abstract

Induction of Controllable Vortex Flow in a New Aorta Stenosis Model for Potential Aorta Mechanobiology Study: A Flow Simulation Platform

Background: Abdominal aortic aneurysms (AAA) are common, particularly among individuals over age 65, with a prevalence of 9%. To better understand the natural history of AAAs, one critical knowledge gap must be filled to elucidate the role of vortical flow in vascular degradation and thrombosis formation. We aimed to induce various types of vortical flow with aneurysm-like hemodynamic environments using a novel aorta stenosis model. Such a model will enable us to investigate the interplays between disturbed hemodynamics and vascular pathological remodeling. Methods: In this study, the hemodynamics and geometry of the aorta in rabbits were used to simulate the physiological flow conditions after two adjacent stenoses were created virtually with varying degrees of area reduction (30-70%) and spacing (5-6.8 mm). A physiological blood flow (rate) waveform measured in rabbits using ultrasound Doppler (normalized to 3.0 mL/s) was prescribed to the inlet (i.e., descending aorta), and zero pressure boundary conditions were applied at two outlets (i.e., iliac arteries). 3D computational fluid dynamics (CFD) simulation in five different stenosis configurations was performed using commercial software (Fluent, Version 20, Ansys Inc., PA). In-house software assessed the evolution of flow vortices over three distinct regions post stenosis using an established method. The total volume of vortex flow, the number of vortices, and the phase-to-phase overlap of vortex flows within different post-stenosis regions were derived to characterize the vortex flow. Results: Quantitative and qualitative flow assessments were performed for all five CFD models. Firstly, in all models, we found consistent patterns of the three vortex flow parameters, indicating that the adjacent stenoses induced three different hemodynamic zones in the post-stenosis regions, namely, stable vortical flow (after first stenosis), transient flow (after second stenosis), unstable vortical flow (further distal to second stenosis). Moreover, increased stenosis degree or reduced spacing led to reduced vortex flow number but increased total volume of vortex flow. The distinctions of the three regions were most significant in the model with 50% and then 30% stenoses, and with a 5 mm (center-to-center) spacing between two stenoses. Conclusions: CFD simulations can offer a powerful tool to predict complex flows using subject-specific vasculature. Such a flow simulation platform is valuable for guiding experimental design or therapy in various diseases. We demonstrated that it is feasible to adjust and achieve multiple types of vortical flows with the novel stenosis model. The three zones with distinct hemodynamic environments allow us to investigate the vascular remodeling regulated by the specifics of the eddies. Our ongoing work is implementing optimized aorta stenosis models to preclinical or in vitro studies to reveal the interplays between varying disturbed flow and aneurysm remodeling. We acknowledge funding support from NIH/NIBIB (R01-EB029570A1) and the Health Research Institute of Michigan Technological University. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Control line failure in Angiostrongylus vasorum point-of-care serology test in dogs with angiostrongylosis due tosuspected hook effect.

Angiostrongylosis is a significant differential for a diverse range of clinical signs in dogs, many of whom present acutely and sometimes with fatal consequences. Point-of-care diagnostic assays include a commercially available Angiostrongylus vasorum qualitative direct lateral flow assay. Case records from one referral centre from dogs with an invalid A. vasorum lateral flow assay, comprising an absent control line alongside a visible test line, were reviewed. As control line failure was hypothesised to be due to antigen excess; where available the A. vasorum lateral flow assay was repeated using dilutions of the original serum. Six dogs had an invalid A. vasorum lateral flow assay result. Five dogs had presented with acute-onset, severe clinical disease consistent with angiostrongylosis, and one dog was a clinically healthy in-contact. Clinical suspicion of angiostrongylosis was confirmed using alternative diagnostic testing and/or response to treatment. Repetition of the A. vasorum lateral flow assay, in four cases, using diluted plasma (10% to 12.5% v/v) resulted in the appearance of a control line alongside the visible test line. A heavy burden of A. vasorum infection resulting in angiostrongylosis should be suspected in dogs with compatible clinical signs and an invalid A. vasorum lateral flow assay result due to control failure alongside a visible test line. Repetition of the test with a diluted serum may be considered to account for the hook effect, also known as the postzone phenomenon, as a possible cause.

Psycho-physio-neurological correlates of qualitative attention, emotion and flow experiences in a close-to-real-life extreme sports situation: low- and high-altitude slackline walking.

It has been indicated that extreme sport activities result in a highly rewarding experience, despite also providing fear, stress and anxiety. Studies have related this experience to the concept of flow, a positive feeling that individuals undergo when they are completely immersed in an activity. However, little is known about the exact nature of these experiences, and, there are still no empirical results to characterize the brain dynamics during extreme sport practice. This work aimed at investigating changes in psychological responses while recording physiological (heart rate-HR, and breathing rate-BR) and neural (electroencephalographic-EEG) data of eight volunteers, during outdoors slackline walking in a mountainous environment at two different altitude conditions (1 m-low-walk- and 45 m-high-walk-from the ground). Low-walk showed a higher score on flow scale, while high-walk displayed a higher score in the negative affect aspects, which together point to some level of flow restriction during high-walk. The order of task performance was shown to be relevant for the physiological and neural variables. The brain behavior during flow, mainly considering attention networks, displayed the stimulus-driven ventral attention network-VAN, regionally prevailing (mainly at the frontal lobe), over the goal-directed dorsal attention network-DAN. Therefore, we suggest an interpretation of flow experiences as an opened attention to more changing details in the surroundings, i.e., configured as a 'task-constantly-opened-to-subtle-information experience', rather than a 'task-focused experience'.

Local mass transfer and flow visualization around a cylinder in a liquid-solid fluidized bed

Adsorption method has been used for flow visualisation and determination of the local and average mass transfer coefficients around a horizontal cylinder in a liquid-solid fluidized bed. The obtained concentration fields on the adsorbent (silica-foils) represent a clear qualitative flow pattern around the cylinder. By comparison of the concentration fields around the cylinder in the single-phase flow and in the fluidized bed, a significant disturbance of the boundary layer by fluidized particles can be observed. Local mass transfer coefficients were shown to be dependent on the angular position around the cylinder with the maximum determined at the angle 140? (measured from the stagnant point 0?). Selected correlations were applied to predict the average mass transfer coefficients and the two best have shown deviations from the experimental data up to 5 %.

Спектр сверхзвукового обтекания вокруг летательного аппарата с управляющими тормозными щитками

The article presents the results of the study of the spatial flow pattern of the aircraft model, the study of the flow structure near the surface of the aircraft by experimental and numerical methods. Comparative materials for visualizing flows around a conical model with a stern control body – a flat end shield during supersonic flight in atmospheric pressure air are presented. The difference from the qualitative flow pattern according to experimental spectra at M≈4 and M≈5.5 lies in the presence, in addition to the formation of a breakaway flow zone in front of the shield, an oblique jump of the seal (from the point of separation of the flow) and a more intense direct jump of the seal, the possibility of the appearance of a flow separation zone induced by the shield on the side of the model surface opposite the shield, with the formation of an oblique jump of the seal. The efficiency of increasing the number of brake shields installed on the cylindrical-conical model is considered. The results of measurements of the dependence of the increments of the drag coefficient of the tested models on the area of the shields are presented.

Qualitative flow metabolic phenotype of pancreatic cancer. A new prognostic biomarker?

BackgroundRetrospective analysis to investigate the relationship between the flow-metabolic phenotype and overall survival (OS) of pancreatic ductal adenocarcinoma (PDAC) and its potential clinical utility. MethodsPatients with histopathologically proven PDAC between 2005 and 2014 using tumor attenuation on routine pre-operative CECT as a surrogate for the vascularity and [18F]FDG-uptake as a surrogate for metabolic activity on [18F]FDG-PET. ResultsIn total, 93 patients (50 male, 43 female, median age 63) were included. Hypoattenuating PDAC with high [18F]FDG-uptake has the poorest prognosis (median OS 7 ± 1 months), compared to hypoattenuating PDAC with low [18F]FDG-uptake (median OS 11 ± 3 months; p = 0.176), iso- or hyperattenuating PDAC with high [18F]FDG-uptake (median OS 15 ± 5 months; p = 0.004) and iso- or hyperattenuating PDAC with low [18F]FDG-uptake (median OS 23 ± 4 months; p = 0.035). In multivariate analysis, surgery combined with tumor differentiation, tumor stage, systemic therapy and flow metabolic phenotype remained independent predictors for overall survival. DiscussionThe novel qualitative flow-metabolic phenotype of PDAC using a combination of CECT and [18F]FDG-PET features, predicted significantly worse survival for hypoattenuating-high uptake pancreatic cancers compared to the other phenotypes.

Pengaruh Buku Suplemen Digital Terintegrasi Mitigasi Bencana Berbantuan LKPD terhadap Keterampilan Kolaborasi Peserta Didik Materi Sistem Ekskresi di SMPN 32 Padang

Skills training is one of the skills required to be developed in 21st century competencies. Skills training is a very important social skill for students to have, especially in learning science. Science learning requires students to understand scientifically so that students get direct experience. The purpose of this study was to determine the effect of using disaster integrated digital supplement books on students' skills in excretion system material at SMPN 32 Padang. The research method used is quasi-experimental. The instruments used in this study were questionnaires and observation sheets. The data analysis technique of this research is adjusted to the qualitative data analysis flow. Based on the results of the research, it means that the use of digital supplement books is integrated with the impact of disasters on students' skills on excretion system material at SMPN 32 Padang. In both classes there are also significant differences in scores between the experimental class and the control class. Based on the average of the two classes, the experimental class that was treated had a higher average of 72 compared to the average of the control class, which was 65.

A simultaneous qualitative and quantitative lateral flow immunoassay for on-site and rapid detection of streptomycin in pig blood serum and urine

Veterinary antibiotic residues are major contaminants in animal-derived foods and dairy products, and the consumption of contaminated products is associated with severe health risks. Among the wide range of veterinary antibiotics, streptomycin (STR, an aminoglycoside commonly used to treat bacterial infections) is widely administered to livestock. Hence, efficient on-site sensing strategies are required to detect veterinary antibiotics. Using gold nanoparticles (AuNPs), we fabricated a one-step lateral flow immunochromatographic assay (LFIA) for the simultaneous quantitative and qualitative detection of STR in pig serum and urine samples. A specific anti-streptomycin monoclonal antibody was conjugated with AuNPs to fabricate LFIA test strips. Several key parameters were optimized to enhance the sensitivity of the LFIA sensor. The visual limit of detection of the sensor was 5 ng/mL for both serum and urine spiked samples, and cut-off values for serum and urine were 20 ng/mL and 22 ng/mL, respectively, which demonstrated the developed LFIA sensor is highly sensitive for detecting STR. Furthermore, test strips had good reliability and produced results within 10 min without the need for professional personnel or specialized equipment. We also combined the LFIA test strips with an LFIA reader to obtain quantitative results and assess risk ranges. The success rates of the LFIA reader for serum and urine sample testing were 95.5 % and 91 %, respectively. These results indicate the test strips could be utilized as a significant sensing strategy for semi quantitative, qualitative, and quantitative on-site detection of STR in pig serum and urine samples before slaughter.

Measuring porous media velocity fields and grain bed architecture with a quantitative PLIF-based technique

Porous media flows are common in both natural and anthropogenic systems. Mapping these flows in a laboratory setting is challenging and often requires non-intrusive measurement techniques, such as particle image velocimetry (PIV) coupled with refractive index matching (RIM). RIM-coupled PIV allows the mapping of velocity fields around transparent solids by analyzing the movement of neutrally buoyant micron-sized seeding particles. The use of this technique in a porous medium can be problematic because seeding particles adhere to grains, which causes the grain bed to lose transparency and can obstruct pore flows. Another non-intrusive optical technique, planar laser-induced fluorescence (PLIF), can be paired with RIM and does not have this limitation because fluorescent dye is used instead of particles, but it has been chiefly used for qualitative flow visualization. Here, we propose a quantitative PLIF-based methodology to map both porous media flow fields and porous media architecture. Velocity fields are obtained by tracking the advection-dominated movement of the fluorescent dye plume front within a porous medium. We also propose an automatic tracking algorithm that quantifies 2D velocity components as the plume moves through space in both an Eulerian and a Lagrangian framework. We apply this algorithm to three data sets: a synthetic data set and two laboratory experiments. Performance of this algorithm is reported by the mean (bias error, B) and standard deviation (random error, SD) of the residuals between its results and the reference data. For the synthetic data, the algorithm produces maximum errors of B & SD = 32% & 23% in the Eulerian framework, respectively, and B & SD = −0.04% & 3.9% in the Lagrangian framework. The small-scale laboratory experimental data requires the Eulerian framework and produce errors of B & SD = −0.5% & 33%. The Lagrangian framework is used on the large-scale laboratory experimental data and produces errors of B & SD = 5% & 44%. Mapping the porous media architecture shows negligible error for reconstructing calibration grains of known dimensions.

Use of Targeted Orographic Smoothing in Very High Resolution Simulations of a Downslope Windstorm and Rotor in a Sub-tropical Highland Location

Nested simulations of a downslope windstorm over Cangshan mountain, Yunnan, China, have been used to demonstrate a method of topographic smoothing that preserves a relatively large amount of terrain detail compared to typical smoothing procedures required for models with terrain-following grids to run stably. The simulations were carried out using the Met Office Unified Model (MetUM) to investigate downslope winds. The smoothing method seamlessly blends two terrain datasets to which uniform smoothing has been applied–one with a minimum of smoothing, the other smoothed more heavily to remove gradients that would cause model instabilities. The latter dataset dominates the blend where the steepest slopes exist, but this is localised and recedes outside these areas. As a result, increased detail is starkly apparent in depictions of flow simulated using the blend, compared to one using the default approach. This includes qualitative flow details that were absent in the latter, such as narrow shooting flows emerging from roughly 1–2 km wide leeside channels. Flow separation is more common due to steeper lee slopes. The use of targeted smoothing also results in increased lee side temporal variability at a given point during the windstorm, including over flat areas. Low-/high-pass filtering of the wind perturbation field reveals that relative spatial variability above 30 km in scale (reflecting the background flow) is similar whether or not targeting is used. Beneath this scale, when smoothing is targeted, relative flow variability decreases at the larger scales, and increases at lower scales. This seems linked to fast smaller scale flows disturbing more coherent flows (notably an along-valley current over Erhai Lake). Spatial variability of winds in the model is unsurprisingly weaker at key times than is observed across a local network sampling mesoscale variation, but results are compromised due to relatively few observation locations sampling the windstorm. Only when targeted smoothing is applied does the model capture the downslope windstorm’s extension over the city of Dali at the mountain’s foot, and the peak mean absolute wind.

Effect of atomizer and cross-flows on liquid and gelled Jet A-1 fuel injection

The current study aims to experimentally investigate the effect of atomizer and cross-flow velocities on liquid and gelled Jet A-1 fuels. For gelled Jet A-1, Jet A-1 liquid, Thixatrol® ST and rectified xylene are the base fuel, gellant and solvent, respectively. Gelled Jet A-1 is prepared by adding 85% by weight of base fuel along with 7.5% by weight of gellant and solvent, each at optimum processing conditions. Atomization using a simple-plain-orifice atomizer is investigated to understand its effect on Jet A-1 gel fuel break-up without air cross-flow. Based on the investigation from qualitative flow visualization and quantitative analysis of Jet A-1 gel fuel break-up, a modified simple-plain-orifice atomizer called an internally impinging air-blast atomizer is made. Primary atomization using this new atomizer is studied to understand the break-up of liquid and gelled Jet A-1 gel fuels without any air cross-flow. Secondary atomization of liquid and gel fuel is investigated by transversely injecting fuel into different low-speed subsonic air cross-flow environments. Laser sheet Imaging (LSI) technique is used to capture spray images of both fuels. Break-up mechanisms of both liquid and gel fuels were observed, and the results were compared. Information on the cross-flow air mass flow rate effect on the liquid and gel spray is extracted by developing an algorithm in MATLAB using an image processing tool. Relative droplet size distribution of liquid and gel spray revealed their dependence on cross-flow air mass flow rate. Total droplet count of both liquid and gel fuel decreases significantly as the cross-flow Reynolds’ number increases. At higher cross-flow Reynolds’ number, gel droplets in the flow are observed to be more as compared to liquid fuel.

Experimental analysis of flow topology and particle behavior in microcavities

Efficient hydrodynamic particle trapping requires the precise control of flow structures that serve as hydrodynamic traps. Microfluidic structures, such as microcavities of various shapes and sizes, can be applied as hydrodynamic traps, and the exerting force can be controlled by changing the geometrical parameters and flow regimes of the cavities. In this study, the capability of trapping microparticles in rectangular, semicircular, and triangular microcavities is experimentally investigated. The flow structure in microcavities with a length-to-depth ratio L/h of 1–4 for rectangular cavities and L/h = 1–2 for semicircular and triangular cavities at a Reynolds number ranging between 1 and 1000 is visualized using a microparticle image velocimetry system. Additionally, patches of 20 µm particles are visualized using a high-speed camera. Different flow phases, namely attached, transitional, and separated, are observed and correlated with the cavity parameters and flow regime. Additionally, qualitative flow parameters determining particle behavior, such as the vortex center location and temporal vortical stability, are analyzed. Finally, the particle behavior is correlated with the flow structure in the cavities, and guidelines for the development of the optimal design of micro- and nanofluidic devices are discussed.

Stratified inclined duct: direct numerical simulations

The stratified inclined duct (SID) experiment consists of a zero-net-volume exchange flow in a long tilted rectangular duct, which allows the study of realistic stratified shear flows with sustained internal forcing. We present the first three-dimensional direct numerical simulations (DNS) of SID to explore the transitions between increasingly turbulent flow regimes first described by Meyer & Linden (J. Fluid Mech., vol. 753, 2014, pp. 242–253). We develop a numerical set-up that faithfully reproduces the experiments and sustains the flow for arbitrarily long times at minimal computational cost. We recover the four qualitative flow regimes found experimentally in the same regions of parameter space: laminar flow, waves, intermittent turbulence and fully developed turbulence. We find good qualitative and quantitative agreement between DNS and experiments and highlight the added value of DNS to complement experimental diagnostics and increase our understanding of the transition to turbulence, both temporally (laminar/turbulent cycles) and parametrically (as the tilt angle of the duct and the Reynolds number are increased). These results demonstrate that numerical studies of SID – and deeper integration between simulations and experiments – have the potential to lead to a better understanding of stratified turbulence.

Large, Wide-Neck, Side-Wall Aneurysm Treatment in Canines Using NeuroCURE: A Novel Liquid Embolic.

Untreated intracranial aneurysms can rupture and result in high rates of morbidity and mortality. Although there are numerous approved endovascular aneurysm treatment devices, most require dual anti-platelet therapy, are minimally biocompatible, or are prone to recanalization. Neurovascular Controlled Uniform Rapid Embolic (NeuroCURE) is an innovative polymer gel material with long-term stability, biocompatibility, and hemocompatibility developed for the treatment of large, wide-neck aneurysms. Sidewall aneurysms were surgically created in 10 canines and NeuroCURE was injected through a 0.025 microcatheter under a single balloon inflation period. Aneurysm treatment was angiographically assessed post-embolization and pre-term with Raymond-Roy occlusion classification and a qualitative flow grade scale. Aneurysm neck stability and biocompatibility was histologically assessed to grade platelet/fibrin thrombus, percent endothelialization, and neointimal formation. Aneurysm sac stability was assessed by NeuroCURE sac content, inflammation, and neo-angiogenesis scales. Explanted aneurysms exhibited a smooth surface at the aneurysm neck with nearly complete neointimal coverage at 3-months. By 6-months, neck endothelialization was 100% in all animals (average Raymond-Roy occlusion classification of 1.2), with no instances of aneurysm recanalization or parent vessel flow compromise. Biocompatibility assessments verified a lack of inflammatory response, neo-angiogenesis, and platelet/fibrin thrombus formation. The NeuroCURE material promotes progressive occlusion of wide-necked side wall aneurysms over time without the need for dual antiplatelet agents. NeuroCURE also promotes neointimal tissue infill without dependence on thrombus formation and thus resists aneurysm recanalization. NeuroCURE remains a compelling investigational device for the treatment of intracranial aneurysms.

Doppler flow morphology characteristics of epiaortic arteries in aortic valve pathologies: a retrospective study on a cohort of patients with ischemic stroke

Background and aimsNeurovascular ultrasound (nvUS) of the epiaortic arteries is an integral part of the etiologic workup in patients with ischemic stroke. Aortic valve disease shares similar vascular risk profiles and therefore not only presents a common comorbidity, but also an etiologic entity. The aim of this study is to investigate the predictive value of specific Doppler curve flow characteristics in epiaortic arteries and the presence of aortic valve disease.MethodsRetrospective, single-center analysis of ischemic stroke patients, both receiving full nvUS of the extracranial common- (CCA), internal- (ICA) and external carotid artery (ECA) and echocardiography (TTE/TEE) during their inpatient stay. A rater blinded for the TTE/TEE results investigated Doppler flow curves for the following characteristics: ‘pulsus tardus et parvus’ for aortic valve stenosis (AS) and ‘bisferious pulse’, ‘diastolic reversal’, ‘zero diastole’ and ‘no dicrotic notch’ for aortic valve regurgitation (AR). Predictive value of these Doppler flow characteristics was investigated using multivariate logistic regression models.ResultsOf 1320 patients with complete examination of Doppler flow curves and TTE/TEE, 75 (5.7%) showed an AS and 482 (36.5%) showed an AR. Sixty-one (4.6%) patients at least showed a moderate-to-severe AS and 100 (7.6%) at least showed a moderate-to-severe AR. After adjustment for age, coronary artery disease, arterial hypertension, diabetes mellitus, smoking, peripheral arterial disease, renal failure and atrial fibrillation, the following flow pattern predicted aortic valve disease: ‘pulsus tardus et parvus’ in the CCA and ICA was highly predictive for a moderate-to-severe AS (OR 1158.5, 95% CI 364.2–3684.8, p < 0.001). ‘No dicrotic notch’ (OR 102.1, 95% CI 12.4–839.4, p < 0.001), a ‘bisferious pulse’ (OR 10.8, 95% CI 3.2–33.9, p < 0.001) and a ‘diastolic reversal’ (OR 15.4, 95% CI 3.2–74.6, p < 0.001) in the CCA and ICA predicted a moderate-to-severe AR. The inclusion of Doppler flow characteristics of the ECA did not increase predictive value.ConclusionsWell defined, qualitative Doppler flow characteristics detectable in the CCA and ICA are highly predictive for aortic valve disease. The consideration of these flow characteristics can be useful to streamline diagnostic and therapeutic measures, especially in the outpatient setting.

CFD Assessment of the Bubble Flow in a 3D Rectangular Column

The purpose of this research is to better understand the characteristics of two-phase flow in a rectangular bubble column. Computational Fluid Dynamics (CFD) (ANSYS-FLUENT R15.0®) has been used to conduct numerical studies of the flow pattern. Furthermore, the experimental data is used to verify the accuracy of the numerical data. This unique CFD simulation research included a 3D system, Reynolds-Average, Navier-Stokes equations (RANS), k-turbulence model, and total interphase forces. Bulk flow patterns were revealed through CFD analysis. Total contact force, both constant and non-steady, is also analyzed for its impact. The data show liquid upflow in the column's bulk section and liquid downflow near the wall. In the gas phase, bubbles rose in the middle area and departed the bed. In addition, bubbles without enough velocity to leave the bed circulate towards the wall with liquid and follow a similar pattern. The results show that the phenomenon of the central peak can only be captured by using a single bubble and no drag forces. The correlation between simulation and experimental findings is excellent. Within the higher, middle, and nearby gas distributor height ranges, the outcome agrees extremely well with the experiment. In addition, the results of the experiments show that the level of turbulence has played a crucial role in dynamic behavior. The CFD model described qualitative and quantitative flow performance, producing excellent results. The results also gave a framework for comparing and evaluating future designs and gave insights into the fluid dynamics of the bubble column reactor. Efforts were made to compare and contrast the main operating modes of different reactor designs. Keywords: Two phase, Ansys, Bubble column, CFD, Drag force, Flow Pattern.