scholarly journals Impact of CT Injector Technology and Contrast Media Viscosity on Vascular Enhancement: Evaluation in a Circulation Phantom

2020 ◽  
Vol 93 (1109) ◽  
pp. 20190868
Author(s):  
Michael McDermott ◽  
Corey Kemper ◽  
William Barone ◽  
Gregor Jost ◽  
Jan Endrikat
Keyword(s):  
Clinical Study ◽  
Pulmonary Artery ◽  
Contrast Media ◽  
Viscosity Ratio ◽  
Injection System ◽  
System Technology ◽  
Low Viscosity ◽  
Expected Performance ◽  
Vascular Enhancement ◽  
The Impact

Objective: To assess the impact of piston-based vs peristaltic injection system technology and contrast media viscosity on achievable iodine delivery rates (IDRs) and vascular enhancement in a pre-clinical study. Methods: Four injectors were tested: MEDRAD® Centargo, MEDRAD® Stellant, CT Exprès®, and CT motion™ using five contrast media [iopromide (300 and 370 mgI ml−1), iodixanol 320 mgI ml−1, iohexol 350 mgI ml−1, iomeprol 400 mgI ml−1]. Three experiments were performed evaluating achievable IDR and corresponding enhancement in a circulation phantom. Results: Experiment I: Centargo provided the highest achievable IDRs with all tested contrast media (p < 0.05). Iopromide 370 yielded the highest IDR with an 18G catheter (3.15 gI/s); iopromide 300 yielded the highest IDR with 20G (2.70 gI/s) and 22G (1.65 gI/s) catheters (p < 0.05). Experiment II: with higher achievable IDRs, piston-based injectors provided significantly higher peak vascular enhancement (up to 48% increase) than the peristaltic injectors with programmed IDRs from 1.8 to 2.4 gI/s (p < 0.05). Experiment III: with programmed IDRs (e.g. 1.5 gI/s) achievable by all injection systems, Centargo, with sharper measured bolus shape, provided significant increases in enhancement of 34–73 HU in the pulmonary artery with iopromide 370 (p < 0.05). Conclusion: The tested piston-based injection systems combined with low viscosity contrast media provide higher achievable IDRs and higher peak vascular enhancement than the tested peristaltic-based injectors. With equivalent IDRs, Centargo provides higher peak vascular enhancement due to improved bolus shape. Advances in knowledge: This paper introduces a new parameter to compare expected performance among contrast media: the concentration/viscosity ratio. Additionally, it demonstrates previously unexplored impacts of bolus shape on vascular enhancement.

scholarly journals Robust Step Detection from Different Waist-Worn Sensor Positions: Implications for Clinical Studies

2020 ◽  
Vol 4 (1) ◽  
pp. 50-58
Author(s):  
Matthias  Tietsch ◽  
Amir Muaremi ◽  
Ieuan Clay ◽  
Felix Kluge ◽  
Holger Hoefling ◽  
...  
Keyword(s):  
Clinical Study ◽  
Clinical Studies ◽  
Neurological Diseases ◽  
Human Gait ◽  
Robust Solution ◽  
Step Detection ◽  
Study Protocols ◽  
Study Results ◽  
Wide Range ◽  
The Impact

Analyzing human gait with inertial sensors provides valuable insights into a wide range of health impairments, including many musculoskeletal and neurological diseases. A representative and reliable assessment of gait requires continuous monitoring over long periods and ideally takes place in the subjects’ habitual environment (real-world). An inconsistent sensor wearing position can affect gait characterization and influence clinical study results, thus clinical study protocols are typically highly proscriptive, instructing all participants to wear the sensor in a uniform manner. This restrictive approach improves data quality but reduces overall adherence. In this work, we analyze the impact of altering the sensor wearing position around the waist on sensor signal and step detection. We demonstrate that an asymmetrically worn sensor leads to additional odd-harmonic frequency components in the frequency spectrum. We propose a robust solution for step detection based on autocorrelation to overcome sensor position variation (sensitivity = 0.99, precision = 0.99). The proposed solution reduces the impact of inconsistent sensor positioning on gait characterization in clinical studies, thus providing more flexibility to protocol implementation and more freedom to participants to wear the sensor in the position most comfortable to them. This work is a first step towards truly position-agnostic gait assessment in clinical settings.

scholarly journals Identifying Critical Binder Attributes to Facilitate Binder Selection for Efficient Formulation Development in a Continuous Twin Screw Wet Granulation Process

Pharmaceutics ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 210
Author(s):  
Lise Vandevivere ◽  
Maxine Vangampelaere ◽  
Christoph Portier ◽  
Cedrine de Backere ◽  
Olaf Häusler ◽  
...  
Keyword(s):  
Dissolution Kinetics ◽  
Wet Granulation ◽  
Continuous Manufacturing ◽  
Formulation Development ◽  
Granulation Process ◽  
Low Viscosity ◽  
Twin Screw ◽  
Poorly Soluble ◽  
Selection For ◽  
The Impact

The suitability of pharmaceutical binders for continuous twin-screw wet granulation was investigated as the pharmaceutical industry is undergoing a switch from batch to continuous manufacturing. Binder selection for twin-screw wet granulation should rely on a scientific approach to enable efficient formulation development. Therefore, the current study identified binder attributes affecting the binder effectiveness in a wet granulation process of a highly soluble model excipient (mannitol). For this formulation, higher binder effectiveness was linked to fast activation of the binder properties (i.e., fast binder dissolution kinetics combined with low viscosity attributes and good wetting properties by the binder). As the impact of binder attributes on the granulation process of a poorly soluble formulation (dicalcium phosphate) was previously investigated, this enabled a comprehensive comparison between both formulations in current research focusing on binder selection. This comparison revealed that binder attributes that are important to guide binder selection differ in function of the solubility of the formulation. The identification of critical binder attributes in the current study enables rational and efficient binder selection for twin-screw granulation of well soluble and poorly soluble formulations. Binder addition proved especially valuable for a poorly soluble formulation.

scholarly journals Stent interventions for pulmonary artery stenosis improve bi-ventricular flow efficiency in a swine model

2021 ◽  
Vol 23 (1) ◽  
Author(s):  
Ryan J. Pewowaruk ◽  
Gregory P. Barton ◽  
Cody Johnson ◽  
J. Carter Ralphe ◽  
Christopher J. Francois ◽  
...  
Keyword(s):  
Ejection Fraction ◽  
Pulmonary Artery ◽  
Ventricular Function ◽  
Intervention Group ◽  
Left Ventricular ◽  
Pulmonary Artery Stenosis ◽  
Swine Model ◽  
4D Flow ◽  
4D Flow Cmr ◽  
The Impact

Abstract Background Branch pulmonary artery (PA) stenosis (PAS) commonly occurs in patients with congenital heart disease (CHD). Prior studies have documented technical success and clinical outcomes of PA stent interventions for PAS but the impact of PA stent interventions on ventricular function is unknown. The objective of this study was to utilize 4D flow cardiovascular magnetic resonance (CMR) to better understand the impact of PAS and PA stenting on ventricular contraction and ventricular flow in a swine model of unilateral branch PA stenosis. Methods 18 swine (4 sham, 4 untreated left PAS, 10 PAS stent intervention) underwent right heart catheterization and CMR at 20 weeks age (55 kg). CMR included ventricular strain analysis and 4D flow CMR. Results 4D flow CMR measured inefficient right ventricular (RV) and left ventricular (LV) flow patterns in the PAS group (RV non-dimensional (n.d.) vorticity: sham 82 ± 47, PAS 120 ± 47; LV n.d. vorticity: sham 57 ± 5, PAS 78 ± 15 p < 0.01) despite the PAS group having normal heart rate, ejection fraction and end-diastolic volume. The intervention group demonstrated increased ejection fraction that resulted in more efficient ventricular flow compared to untreated PAS (RV n.d. vorticity: 59 ± 12 p < 0.01; LV n.d. vorticity: 41 ± 7 p < 0.001). Conclusion These results describe previously unknown consequences of PAS on ventricular function in an animal model of unilateral PA stenosis and show that PA stent interventions improve ventricular flow efficiency. This study also highlights the sensitivity of 4D flow CMR biomarkers to detect earlier ventricular dysfunction assisting in identification of patients who may benefit from PAS interventions.

Investigating the influence of carbon nanotube on the performance of asphalt binder

2021 ◽  
pp. 147776062110194
Author(s):  
Peerzada Mosir Shah ◽  
Mohammad Shafi Mir
Keyword(s):  
High Temperature ◽  
Asphalt Binder ◽  
Storage Condition ◽  
Modified Bitumen ◽  
Creep And Recovery ◽  
Low Viscosity ◽  
Temperature Performance ◽  
Modified Asphalt Binder ◽  
Viscosity Grade ◽  
The Impact

The purpose of this study aims at investigating the impact of multi-walled carbon nanotubes (MWCNT’s) on the properties of low viscosity grade asphalt binder. Asphalt binder with viscosity grade-10 is selected as the control binder and later it is modified with different percentages of MWCNT’s (0.5–2.5%). Penetration, softening point, ductility and rotational viscosity test were employed for evaluating the effect of MWCNT’s on basic physical properties of modified asphalt binder. Dynamic Shear Rheometer (DSR) is used for evaluating the rheological properties of the base and modified bitumen, for both aged and unaged bitumen. Based on the conventional and basic rheological tests, it was seen that the addition of MWCNT’s improved the high-temperature performance of modified bitumen. Multiple Stress Creep and Recovery (MSCR) test results revealed that the addition of MWCNT’s improved the creep and recovery of modified binders for both stress intensities (0.1 kPa and 3.2 kPa) which confirms that the modified binder is more rut resistant. Moreover, it was observed that there was a significant improvement in the aging resistance of the asphalt binder due to addition of MWCNTs. However low temperature performance of MWCNTs was not encouraging. Also, MWCNTs addition to asphalt binder was found to be stable under high-temperature storage condition. Overall, there is a significant amount of improvement using MWCNTs in the base asphalt binder.

scholarly journals An Effective Method for Preparation of Liquid Phosphoric Anhydride and Its Application in Flame Retardant Epoxy Resin

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2205
Author(s):  
Qian Li ◽  
Yujie Li ◽  
Yifan Chen ◽  
Qiang Wu ◽  
Siqun Wang
Keyword(s):  
Flame Retardant ◽  
Epoxy Resin ◽  
Epoxy Resins ◽  
Oxygen Index ◽  
Decomposition Temperature ◽  
Ease Of Use ◽  
Limiting Oxygen Index ◽  
Good Thermal Stability ◽  
Low Viscosity ◽  
The Impact

A novel liquid phosphorous-containing flame retardant anhydride (LPFA) with low viscosity was synthesized from 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and methyl tetrahydrophthalic anhydride (MeTHPA) and further cured with bisphenol-A epoxy resin E-51 for the preparation of the flame retardant epoxy resins. Both Fourier transform infrared spectroscopy (FT-IR), mass spectrometry (MS) and nuclear magnetic resonance (NMR) measurements revealed the successful incorporation of DOPO on the molecular chains of MeTHPA through chemical reaction. The oxygen index analysis showed that the LPFA-cured epoxy resin exhibited excellent flame retardant performance, and the corresponding limiting oxygen index (LOI) value could reach 31.2%. The UL-94V-0 rating was achieved for the flame retardant epoxy resin with the phosphorus content of 2.7%. With the addition of LPFA, the impact strength of the cured epoxy resins remained almost unchanged, but the flexural strength gradually increased. Meanwhile, all the epoxy resins showed good thermal stability. The glass transition temperature (Tg) and thermal decomposition temperature (Td) of epoxy resin cured by LPFA decreased slightly compared with that of MeTHPA-cured epoxy resin. Based on such excellent flame retardancy, low viscosity at room temperature and ease of use, LPFA showed potential as an appropriate curing agent in the field of electrical insulation materials.

scholarly journals The impact of betamethasone on fetal pulmonary, umbilical and middle cerebral artery Doppler velocimetry and its relationship with neonatal respiratory distress syndrome

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Homeira Vafaei ◽  
Fahimeh Kaveh Baghbahadorani ◽  
Nasrin Asadi ◽  
Maryam Kasraeian ◽  
Azam Faraji ◽  
...  
Keyword(s):  
Pulmonary Artery ◽  
Respiratory Distress Syndrome ◽  
Respiratory Distress ◽  
Middle Cerebral Artery ◽  
Cerebral Artery ◽  
Distress Syndrome ◽  
Exposed Group ◽  
Doppler Velocity ◽  
Corticosteroid Administration ◽  
The Impact

Abstract Background Prenatal corticosteroid administration is known to be an effective strategy in improving fetal pulmonary maturity. This study aimed to evaluate the impact of maternal betamethasone administration on fetal pulmonary and other arteries Doppler velocity and the correlation between RDS development and Doppler indices results. Methods Fifty one singleton pregnancies between 26 and 34 gestational weeks with a diagnosis of preterm labor were included in the exposed group and received betamethasone. Fifty one uncomplicated pregnancies were included in the non-exposed group. Fetal pulmonary, umbilical and middle cerebral arteries Doppler parameters were evaluated before and 24 to 48 h after steroid administration in the exposed group and two times at same intervals in the non-exposed group. Maternal records were matched to neonatal charts if delivery happened, and demographic and outcome data were abstracted. Results When compared with the nonexposed group, fetuses treated with corticosteroids demonstrated significantly decreased umbilical artery Pulsatility index (PI) and significantly increased the middle cerebral artery PI, pulmonary artery Acceleration time (AT) and pulmonary artery AT/ET (Ejection time), while all other indices remained similar. We found significantly decreased pulmonary artery AT in the fetuses with respiratory distress syndrome (RDS) compared to those that did not. Conclusions The results of our study showed that maternal antenatal betamethasone administration caused significant changes in the fetus blood velocity waveforms and also affected the blood flow in the pulmonary artery which led to an increase in the pulmonary artery AT and AT/ET. Among those fetuses with RDS, we found a significant decrease in the pulmonary artery AT, but we did not observe any pulmonary artery AT/ET differences.

Abstract 15388: Persistent Pulmonary Hypertension After Transcatheter Aortic Valve Implantation: Impact on Mortality

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Maria Drakopoulou ◽  
Konstantinos Stathogiannis ◽  
Konstantinos Toutouzas ◽  
George Latsios ◽  
Andreas Synetos ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Aortic Stenosis ◽  
Pulmonary Artery ◽  
Severe Aortic Stenosis ◽  
Systolic Pressure ◽  
Right Atrial ◽  
Pulmonary Artery Systolic Pressure ◽  
End Point ◽  
The Right ◽  
The Impact

Objective: Severe aortic stenosis leads to increased pulmonary arterial systolic pressure. A controversy still remains regarding the impact of persistent pulmonary hypertension (PHT) on prognosis of patients undergoing transcatheter aortic valve implantation (TAVI). We sought to investigate the impact of persistent PHT on 2-year all-cause mortality of patients with severe aortic stenosis following TAVI. Methods: Patients with severe and symptomatic aortic stenosis (effective orifice area [EOA]≤1 cm 2 ) who were scheduled for TAVI with a self-expanding valve at our institution were prospectively enrolled. Prospectively collected echocardiographic data before and after TAVI were retrospectively analyzed in all patients. Pulmonary artery systolic pressure was estimated as the sum of the right ventricular to the right atrial gradient during systole and the right atrial pressure. PHT following TAVI was classified as absent if <35 mmHg and persistent if ≥35 mmHg. Primary clinical end-point was 2-year all-cause mortality defined according to the criteria proposed by the Valve Academic Research Consortium-2. Results: Hundred and forty patients (mean age: 82±9 years) were included in the study. The primary clinical end point occurred in 17 patients (12%) during a median follow-up period of 2 years. Mean pulmonary artery systolic pressure was reduced in all patients following TAVI (45±9 versus 41±6 mmHg, p<0.01). Mortality rate was higher in patients with persistent PHT compared to patients with normal pulmonary artery systolic pressure following TAVI (26% versus 14 %, p<0.01). Patients that reached the primary clinical end point had a higher post procedural mean systolic pulmonary pressure (43±9 versus 39±6 mmHg, p=0.02). In multivariate regression analysis, persistence of PHT (OR: 2.51, 95% CI: 1.109-7.224, p=0.01) was an independent predictor of long-term mortality. Conclusions: The persistence of pulmonary hypertension after TAVI is associated with long term mortality. Identifying the population that will clearly benefit from TAVI is still need to be validated by larger trials.

scholarly journals A Clinical Study of Cutaneous Adverse Reactions to Nonionic Contrast Media in Korea

2012 ◽  
Vol 24 (1) ◽  
pp. 22 ◽  
Author(s):  
Kyung Eun Jung ◽  
Jimin Chung ◽  
Byung Cheol Park ◽  
Keum Nahn Jee ◽  
Young Koo Jee ◽  
...  
Keyword(s):  
Clinical Study ◽  
Contrast Media ◽  
Adverse Reactions ◽  
Nonionic Contrast Media ◽  
Cutaneous Adverse Reactions

Experimental study of saturation by visible light transmission in dual-scale fibrous reinforcements during composite manufacturing

2017 ◽  
Vol 36 (23) ◽  
pp. 1693-1711 ◽  
Author(s):  
F LeBel ◽  
É Ruiz ◽  
F Trochu
Keyword(s):  
Visible Light ◽  
Light Transmission ◽  
Void Formation ◽  
In Situ Monitoring ◽  
Injection System ◽  
Computer Assisted ◽  
Liquid Composite Molding ◽  
Composite Molding ◽  
The Impact ◽  
Dual Scale

A new in situ monitoring strategy is proposed to study void formation during real-time impregnation of dual-scale fibrous reinforcements in liquid composite molding. Void content data from burn-off tests are used to calibrate a refractive index matching approach based on two optical principles: Beer–Lambert and Fresnel laws. Once calibrated, this approach based on visible light transmission is used to study the impact of key process parameters on the saturation footprint of dual-scale fibrous reinforcements during and after mold filling. The injection parameters investigated are the flow front velocity, the pressure distribution inside the mold cavity, the bleeding flow rate, and the mold packing pressure. The experimental setup is a computer-assisted injection system and a transparent resin transfer molding mold is used to perform unidirectional injections. A vinyl ester resin is injected through E-glass bidirectional non-crimp fabrics under various manufacturing conditions. This investigation not only confirms the decreasing trend in void formation by mechanical entrapment of air with the decrease in impregnation velocity, as it converges toward the optimal impregnation conditions for this fibrous reinforcement reported in previous studies, but it also brings insights on void dissolution and transport in liquid composite molding.

On the Impact of Liquid Drops on Immiscible Liquids

2016 ◽  
Author(s):  
Eduardo Castillo-Orozco ◽  
Ashkan Davanlou ◽  
Pretam K. Choudhury ◽  
Ranganathan Kumar
Keyword(s):  
Oil Spills ◽  
Silicone Oil ◽  
Density Ratio ◽  
High Viscosity ◽  
Impact Behavior ◽  
Immiscible Fluid ◽  
Liquid Droplets ◽  
Liquid Drops ◽  
Low Viscosity ◽  
The Impact

The release of liquid hydrocarbons into the water is one of the environmental issues that have attracted more attention after deepwater horizon oil spill in Gulf of Mexico. The understanding of the interaction between liquid droplets impacting on an immiscible fluid is important for cleaning up oil spills as well as the demulsification process. Here we study the impact of low-viscosity liquid drops on high-viscosity liquid pools, e.g. water and ethanol droplets on a silicone oil 10cSt bath. We use an ultrafast camera and image processing to provide a detailed description of the impact phenomenon. Our observations suggest that viscosity and density ratio of the two media play a major role in the post-impact behavior. When the droplet density is larger than that of the pool, additional cavity is generated inside the pool. However, if the density of the droplet is lower than the pool, droplet momentary penetration may be facilitated by high impact velocities. In crown splash regime, the pool properties as well as drop properties play an important role. In addition, the appearance of the central jet is highly affected by the properties of the impacting droplet. In general, the size of generated daughter droplets as well as the thickness of the jet is reduced compared to the impact of droplets with the pool of an identical fluid.

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