Multi-Objective Robust Design Exploration of a Canine Ventricular Shunt for Managing Hydrocephalus

2021 ◽  
Author(s):  
Gehendra Sharma ◽  
Anand Balu Nellippallil ◽  
Ryan Yingling ◽  
Na Yeon Lee ◽  
Andy Shores ◽  
...  
Keyword(s):  
Robust Design ◽  
Pressure Difference ◽  
Biomedical Devices ◽  
Csf Flow ◽  
Robust Performance ◽  
Design Exploration ◽  
Multi Objective ◽  
Abnormal Accumulation ◽  
Design Solutions ◽  
The Brain

Abstract Hydrocephalus is characterized by the abnormal accumulation of cerebrospinal fluid (CSF) within the ventricles of the brain, resulting in an increase of intracranial pressure (ICP). Ventriculoperitoneal shunts (VPS) are designed to prevent buildup of pressure in the brain by allowing excess CSF flow from the intracranial ventricles to the peritoneal cavity through a shunting mechanism. The shunt design presented in this paper is an inexpensive alternative to VPS, that is, a non-valve ventricular shunt design that directly routes CSF into the subarachnoid space. We recognize that consideration of multiple design criteria and uncertainty management are critical for designing biomedical devices to ensure robust performance. Hence, our objective in this paper is to present a multi-objective robust design exploration of canine shunts for managing hydrocephalus. Our approach in robust design focuses on managing uncertainties to deliver design solutions that are relatively insensitive to uncertainties. Hence, a multi-objective robust design problem is formulated using the compromise Decision Support Problem (cDSP) construct to explore shunt designs that best satisfy the conflicting goals dealing with the pressure difference and the stress, and a robust design goal dealing with the variations in pressure difference. We compare the results against optimal solutions to build confidence in the proposed method to identify design solutions that are relatively insensitive to uncertainties. The method presented is generic and can be applied to the multi-objective robust design of similar biomedical devices.

Multi-Objective Design Exploration of a Canine Ventriculoperitoneal Shunt for Hydrocephalus

2020 ◽  
Author(s):  
Ryan Yingling ◽  
Anand Balu Nellippallil ◽  
Matthew Register ◽  
Travis Hannan ◽  
Jack Simmons ◽  
...  
Keyword(s):  
Ventriculoperitoneal Shunt ◽  
Medical Procedure ◽  
Design Exploration ◽  
Multi Objective ◽  
Design Variables ◽  
Inner Diameter ◽  
Decision Based Design ◽  
Associated Design ◽  
The Brain ◽  
Systematic Framework

Abstract Hydrocephalus is a condition that affects humans and animals in which excess cerebrospinal fluid (CSF) builds up within the ventricles of the brain, causing an increase in intracranial pressure. The CSF can be released using a ventriculoperitoneal shunt, which effectively removes the fluid from the ventricles of the brain to the peritoneal cavity. In canines, hydrocephalus is sometimes a fatal condition complicated by shunt failure due to obstructions. The medical procedure is also expensive and has a high failure rate over the long term. In this paper, we present a systematic framework to carry out the multi-objective design exploration of canine shunts for managing hydrocephalus. We demonstrate the efficacy of the framework by designing a shunt prototype to meet specific goals of meeting the CSF flow rate target, minimizing shear stress on the shunt, and minimizing shunt weight. The shunt design variables considered for the problem include the inner diameter, inlet hole diameter, and the distance from the inlet holes to the outlet. A multi-objective design problem is formulated using the systematic framework to explore the combination of shunt design variables that best satisfy the conflicting goals defined. The framework and associated design constructs are generic and support the formulation and decision-based design of similar biomedical devices for different health conditions.

scholarly journals Optical Imaging of Beta-Amyloid Plaques in Alzheimer’s Disease

Biosensors ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 255
Author(s):  
Ziyi Luo ◽  
Hao Xu ◽  
Liwei Liu ◽  
Tymish Y. Ohulchanskyy ◽  
Junle Qu
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Optical Imaging ◽  
Imaging Techniques ◽  
High Sensitivity ◽  
Pathological Feature ◽  
Promising Tool ◽  
Abnormal Accumulation ◽  
Accumulation Mechanism ◽  
The Brain

Alzheimer’s disease (AD) is a multifactorial, irreversible, and incurable neurodegenerative disease. The main pathological feature of AD is the deposition of misfolded β-amyloid protein (Aβ) plaques in the brain. The abnormal accumulation of Aβ plaques leads to the loss of some neuron functions, further causing the neuron entanglement and the corresponding functional damage, which has a great impact on memory and cognitive functions. Hence, studying the accumulation mechanism of Aβ in the brain and its effect on other tissues is of great significance for the early diagnosis of AD. The current clinical studies of Aβ accumulation mainly rely on medical imaging techniques, which have some deficiencies in sensitivity and specificity. Optical imaging has recently become a research hotspot in the medical field and clinical applications, manifesting noninvasiveness, high sensitivity, absence of ionizing radiation, high contrast, and spatial resolution. Moreover, it is now emerging as a promising tool for the diagnosis and study of Aβ buildup. This review focuses on the application of the optical imaging technique for the determination of Aβ plaques in AD research. In addition, recent advances and key operational applications are discussed.

Robust Compressor Blades for Desensitizing Operational Tip Clearance Variations

2014 ◽  
Author(s):  
Pranay Seshadri ◽  
Shahrokh Shahpar ◽  
Geoffrey T. Parks
Keyword(s):  
Robust Design ◽  
Total Pressure ◽  
Pressure Rise ◽  
Side Surface ◽  
Tip Clearance ◽  
Design Parameters ◽  
Compressor Blades ◽  
Robust Designs ◽  
Multi Objective ◽  
Mean And Variance

Robust design is a multi-objective optimization framework for obtaining designs that perform favorably under uncertainty. In this paper robust design is used to redesign a highly loaded, transonic rotor blade with a desensitized tip clearance. The tip gap is initially assumed to be uncertain from 0.5 to 0.85% span, and characterized by a beta distribution. This uncertainty is then fed to a multi-objective optimizer and iterated upon. For each iteration of the optimizer, 3D-RANS computations for two different tip gaps are carried out. Once the simulations are complete, stochastic collocation is used to generate mean and variance in efficiency values, which form the two optimization objectives. Two such robust design studies are carried out: one using 3D blade engineering design parameters (axial sweep, tangential lean, re-cambering and skew) and the other utilizing suction and pressure side surface perturbations (with bumps). A design is selected from each Pareto front. These designs are robust: they exhibit a greater mean efficiency and lower variance in efficiency compared to the datum blade. Both robust designs were also observed to have significantly higher aft and reduced fore tip loading. This resulted in a weaker clearance vortex, wall jet and double leakage flow, all of which lead to reduced mixed-out losses. Interestingly, the robust designs did not show an increase in total pressure at the tip. It is believed that this is due to a trade-off between fore-loading the tip and obtaining a favorable total pressure rise and higher mixed-out losses, or aft-loading the tip, obtaining a lower pressure rise and lower mixed-out losses.

scholarly journals The orthopedic characterization of cfap298tm304 mutants validate zebrafish to faithfully model human AIS

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Marie-Hardy Laura ◽  
Cantaut-Belarif Yasmine ◽  
Pietton Raphaël ◽  
Slimani Lotfi ◽  
Pascal-Moussellard Hugues
Keyword(s):  
Cerebrospinal Fluid ◽  
Three Dimensional ◽  
Fluid Circulation ◽  
Micro Computed Tomography ◽  
Csf Flow ◽  
Cerebrospinal Fluid Circulation ◽  
Clinical Criteria ◽  
Brain And Spinal Cord ◽  
The Brain

AbstractCerebrospinal fluid (CSF) circulation relies on the beating of motile cilia projecting in the lumen of the brain and spinal cord cavities Mutations in genes involved in cilia motility disturb cerebrospinal fluid circulation and result in scoliosis-like deformities of the spine in juvenile zebrafish. However, these defects in spine alignment have not been validated with clinical criteria used to diagnose adolescent idiopathic scoliosis (AIS). The aim of this study was to describe, using orthopaedic criteria the spinal deformities of a zebrafish mutant model of AIS targeting a gene involved in cilia polarity and motility, cfap298tm304. The zebrafish mutant line cfap298tm304, exhibiting alteration of CSF flow due to defective cilia motility, was raised to the juvenile stage. The analysis of mutant animals was based on micro-computed tomography (micro-CT), which was conducted in a QUANTUM FX CALIPER, with a 59 µm-30 mm protocol. 63% of the cfap298tm304 zebrafish analyzed presented a three-dimensional deformity of the spine, that was evolutive during the juvenile phase, more frequent in females, with a right convexity, a rotational component and involving at least one dislocation. We confirm here that cfap298tm304 scoliotic individuals display a typical AIS phenotype, with orthopedic criteria mirroring patient’s diagnosis.

scholarly journals Multi-Objective Design Exploration and Its Application to Regional-Jet Wing Design

2007 ◽  
Vol 50 (167) ◽  
pp. 1-8 ◽  
Author(s):  
Shigeru OBAYASHI ◽  
Shinkyu JEONG ◽  
Kazuhisa CHIBA ◽  
Hiroyuki MORINO
Keyword(s):  
Wing Design ◽  
Design Exploration ◽  
Multi Objective

scholarly journals Impact of Fatty Acid-Binding Proteins in α-Synuclein-Induced Mitochondrial Injury in Synucleinopathy

Biomedicines ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 560
Author(s):  
An Cheng ◽  
Wenbin Jia ◽  
Ichiro Kawahata ◽  
Kohji Fukunaga
Keyword(s):  
Fatty Acid ◽  
Binding Proteins ◽  
Neuronal Loss ◽  
Krabbe Disease ◽  
Fatty Acid Binding Proteins ◽  
Mitochondrial Outer Membrane ◽  
Fatty Acid Binding ◽  
Mitochondrial Injury ◽  
Abnormal Accumulation ◽  
The Brain

Synucleinopathies are diverse diseases with motor and cognitive dysfunction due to progressive neuronal loss or demyelination, due to oligodendrocyte loss in the brain. While the etiology of neurodegenerative disorders (NDDs) is likely multifactorial, mitochondrial injury is one of the most vital factors in neuronal loss and oligodendrocyte dysfunction, especially in Parkinson’s disease, dementia with Lewy body, multiple system atrophy, and Krabbe disease. In recent years, the abnormal accumulation of highly neurotoxic α-synuclein in the mitochondrial membrane, which leads to mitochondrial dysfunction, was well studied. Furthermore, fatty acid-binding proteins (FABPs), which are members of a superfamily and are essential in fatty acid trafficking, were reported to trigger α-synuclein oligomerization in neurons and glial cells and to target the mitochondrial outer membrane, thereby causing mitochondrial loss. Here, we provide an updated overview of recent findings on FABP and α-synuclein interactions and mitochondrial injury in NDDs.

scholarly journals Upright versus supine MRI: effects of body position on craniocervical CSF flow

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Marco Muccio ◽  
David Chu ◽  
Lawrence Minkoff ◽  
Neeraj Kulkarni ◽  
Brianna Damadian ◽  
...  
Keyword(s):  
Stroke Volume ◽  
Supine Position ◽  
Cardiac Cycle ◽  
Body Position ◽  
Csf Flow ◽  
Position Change ◽  
Phase Duration ◽  
Brain Functions ◽  
Systolic Phase ◽  
The Brain

Abstract Background Cerebrospinal fluid (CSF) circulation between the brain and spinal canal, as part of the glymphatic system, provides homeostatic support to brain functions and waste clearance. Recently, it has been observed that CSF flow is strongly driven by cardiovascular brain pulsation, and affected by body orientation. The advancement of MRI has allowed for non-invasive examination of the CSF hydrodynamic properties. However, very few studies have addressed their relationship with body position (e.g., upright versus supine). It is important to understand how CSF hydrodynamics are altered by body position change in a single cardiac phase and how cumulative long hours staying in either upright or supine position can affect craniocervical CSF flow. Methods In this study, we investigate the changes in CSF flow at the craniocervical region with flow-sensitive MRI when subjects are moved from upright to supine position. 30 healthy volunteers were imaged in upright and supine positions using an upright MRI. The cranio-caudal and caudo-cranial CSF flow, velocity and stroke volume were measured at the C2 spinal level over one cardiac cycle using phase contrast MRI. Statistical analysis was performed to identify differences in CSF flow properties between the two positions. Results CSF stroke volume per cardiac cycle, representing CSF volume oscillating in and out of the cranium, was ~ 57.6% greater in supine (p < 0.0001), due to a ~ 83.8% increase in caudo-cranial CSF peak velocity during diastole (p < 0.0001) and extended systolic phase duration when moving from upright (0.25 ± 0.05 s) to supine (0.34 ± 0.08 s; p < 0.0001). Extrapolation to a 24 h timeframe showed significantly larger total CSF volume exchanged at C2 with 10 h spent supine versus only 5 h (p < 0.0001). Conclusions In summary, body position has significant effects on CSF flow in and out of the cranium, with more CSF oscillating in supine compared to upright position. Such difference was driven by an increased caudo-cranial diastolic CSF velocity and an increased systolic phase duration when moving from upright to supine position. Extrapolation to a 24 h timeframe suggests that more time spent in supine position increases total amount of CSF exchange, which may play a beneficial role in waste clearance in the brain.

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