RESUMO
Blood plasma viscosity (PV) is an established biomarker for numerous diseases. Measurement of the shear PV using conventional rheological techniques is, however, time consuming and requires significant plasma volumes. Here, we show that Brillouin light scattering (BLS) and angle-resolved spectroscopy measurements of the longitudinal PV from microliter-sized plasma volumes can serve as a proxy for the shear PV measured using conventional viscometers. This is not trivial given the distinct frequency regime probed and the longitudinal viscosity, a combination of the shear and bulk viscosity, representing a unique material property on account of the latter. We demonstrate this for plasma from healthy persons and patients suffering from different severities of COVID-19 (CoV), which has been associated with an increased shear PV. We further show that the additional information contained in the BLS-measured effective longitudinal PV and its temperature scaling can provide unique insight into the chemical constituents and physical properties of plasma that can be of diagnostic value. In particular, we find that changes in the effective longitudinal viscosity are consistent with an increased suspension concentration in CoV patient samples at elevated temperatures that is correlated with disease severity and progression. This is supported by results from rapid BLS spatial-mapping, angle-resolved BLS measurements, changes in the elastic scattering, and anomalies in the temperature scaling of the shear viscosity. Finally, we introduce a compact BLS probe to rapidly perform measurements in plastic transport tubes. Our results open a broad avenue for PV diagnostics based on the high-frequency effective longitudinal PV and show that BLS can provide a means for its implementation.
Assuntos
Viscosidade Sanguínea , COVID-19 , Humanos , Viscosidade Sanguínea/fisiologia , COVID-19/sangue , COVID-19/diagnóstico , SARS-CoV-2 , Espalhamento de Radiação , Plasma/química , Luz , Reologia/métodos , MasculinoRESUMO
Background:Dispersion presents both a challenge and a diagnostic opportunity in shear wave elastography (SWE).Shear Wave Rheometry(SWR) is an inversion technique for processing SWE data acquired using an acoustic radiation force impulse (ARFI) excitation. The main advantage of SWR is that it can characterize the shear properties of homogeneous soft media over a wide frequency range. Assumptions associated with SWR include tissue homogeneity, tissue isotropy, and axisymmetry of the ARFI excitation).Objective:Evaluate the validity of the SWR assumptions in ex vivo bovine liver.Approach:SWR was used to measure the shear properties of bovine liver tissue as function of frequency over a large frequency range. Assumptions associated with SWR (tissue homogeneity, tissue isotropy, and axisymmetry of the ARFI excitation) were evaluated through measurements performed at multiple locations and probe orientations. Measurements focused on quantities that would reveal violations of the assumptions.Main results:Measurements of shear properties were obtained over the 25-250 Hz range, and showed a 4-fold increase in shear storage modulus (from 1 to 4 kPa) and over a 10-fold increase in the loss modulus (from 0.2 to 3 kPa) over that decade-wide frequency range. Measurements under different conditions were highly repeatable, and model error was low in all cases.Significance and Conclusion:SWR depends on modeling the ARFI-induced shear wave as a full vector viscoelastic shear wave resulting from an axisymmetric source; it is agnostic to any specific rheological model. Despite this generality, the model makes three main simplifying assumptions. These results show that the modeling assumptions used in SWR are valid in bovine liver over a wide frequency band.
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Técnicas de Imagem por Elasticidade , Fígado , Reologia , Animais , Bovinos , Fígado/diagnóstico por imagem , Técnicas de Imagem por Elasticidade/métodos , Reologia/métodos , Resistência ao Cisalhamento , Módulo de ElasticidadeRESUMO
Ultrasound velocimetry has been widely used for blood flow imaging. However, the flow measurements are constrained to resolve the in-plane 2D flow components when using a 1D transducer array. In this work, an ultrasound speckle decorrelation analysis-based velocimetry (3C-vUS) is proposed for 3D velocity components measurement using a 1D transducer array. The 3C-vUS theory is first derived and validated with numerical simulations and phantom experiments. The in vivo testing results show that 3C-vUS can accurately measure the blood flow 3D-velocity-components of the human carotid artery at arbitrary probe-to-vessel angles throughout the cardiac cycle. With such capability, the 3C-vUS will alleviate the requirement of operators and promote disease screening for blood flow-related disorders.
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Artérias Carótidas , Imageamento Tridimensional , Imagens de Fantasmas , Reologia , Transdutores , Ultrassonografia , Humanos , Reologia/métodos , Artérias Carótidas/diagnóstico por imagem , Velocidade do Fluxo Sanguíneo/fisiologia , Imageamento Tridimensional/métodos , Ultrassonografia/métodos , Ultrassonografia/instrumentaçãoRESUMO
This study investigates the role of leading-edge (LE) curvature in flapping wing aerodynamics considering hovering and forward flight conditions. A scaled-up robotic model is towed along its longitudinal axis by a rack gear carriage system. The forward velocity of the robotic model is changed by varying the advance ratioJfrom 0 (hovering) to 1.0. The study reveals that the LE curvature has insignificant influence on the cycle-average aerodynamic lift and drag. However, the time-history lift coefficient shows that the curvature can enhance the lift around the middle of downstroke. This enhanced lift is reduced from 5% to 1.2% asJchanged from 0 to 1.0. Further flow examinations reveal that the LE curvature is beneficial by enhancing circulation only at the outboard wing sections. The enhanced outboard circulation is found to emanate from the less stretched leading-edge vortices (LEVs), weakened trailing-edge vortices (TEVs), and the coherent merging of the tip vortices (TVs) with the minor LEVs as observed from the phase-lock planar digital particle image velocimetry measurements. The far-wake observation shows that the LE curvature enhances the vorticity within the TV, helping to reduce the overall flow fluctuations in the far field. These findings can be extended to explain the predominantly straight LE wing shape with a small amount of curvature only observed near the wing tip for flapping fliers with Re from 103to 104.
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Simulação por Computador , Voo Animal , Modelos Biológicos , Robótica , Asas de Animais , Asas de Animais/fisiologia , Asas de Animais/anatomia & histologia , Voo Animal/fisiologia , Animais , Robótica/métodos , Biomimética/métodos , Fenômenos Biomecânicos , Reologia/métodos , Desenho de EquipamentoRESUMO
It is structurally pertinent to understudy the important roles the self-compacting concrete (SCC) yield stress and plastic viscosity play in maintaining the rheological state of the concrete to flow. It is also important to understand that different concrete mixes with varying proportions of fine to coarse aggregate ratio and their nominal sizes produce different and corresponding flow- and fill-abilities, which are functions of the yield stress/plastic viscosity state conditions of the studied concrete. These factors have necessitated the development of regression models, which propose optimal rheological state behavior of SCC to ensure a more sustainable concreting. In this research paper on forecasting the rheological state properties of self-compacting concrete (SCC) mixes by using the response surface methodology (RSM) technique, the influence of nominal sizes of the coarse aggregate has been studied in the concrete mixes, which produced experimental mix entries. A total of eighty-four (84) concrete mixes were collected, sorted and split into training and validation sets to model the plastic viscosity and the yield stress of the SCC. In the field applications, the influence of the sampling sizes on the rheological properties of the concrete cannot be overstretched due to the importance of flow consistency in SCC in order to achieve effective workability. The RSM is a symbolic regression analysis which has proven to exercise the capacity to propose highly performable engineering relationships. At the end of the model exercise, it was found that the RSM proposed a closed-form parametric relationship between the outputs (plastic viscosity and yield stress) and the studied independent variables (the concrete components). This expression can be applied in the design and production of SCC with performance accuracies of above 95% and 90%, respectively. Also, the RSM produced graphical prediction of the plastic viscosity and yield stress at the optimized state conditions with respect to the measured variables, which could be useful in monitoring the performance of the concrete in practice and its overtime assessment. Generally, the production of SCC for field applications are justified by the components in this study and experimental entries beyond which the parametric relations and their accuracies are to be reverified.
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Materiais de Construção , Reologia , Reologia/métodos , Materiais de Construção/análise , Viscosidade , Teste de Materiais/métodos , Previsões/métodosRESUMO
Visualizing a 3D blood flow velocity field through noninvasive imaging is crucial for analyzing hemodynamic mechanisms in areas prone to disorders. However, traditional correlation-based optical coherence tomography (OCT) velocimetry techniques have a maximum measurable flow velocity depending on the A-line rate. We presented the ergodic speckle contrast OCT (ESCOCT) to break the bottleneck in measuring the rapid blood flow velocity. It achieved a measurement of blood flow velocity ranging from 9.5 to 280 mm/s using a 100 kHz swept-source (SS) OCT based on 100 A-repeats scanning mode. Addressing the non-ergodic problem of temporal OCT signals by integrating more consecutive A-scans, ESCOCT can enable the estimation for lower velocity flows by increasing A-repeats. ESCOCT provided a wide dynamic range with no upper limit on measuring blood flow velocity with an adequate signal-to-noise ratio and improved the sensitivity and accuracy of the hemodynamic assessment.
Assuntos
Tomografia de Coerência Óptica , Tomografia de Coerência Óptica/métodos , Velocidade do Fluxo Sanguíneo/fisiologia , Reologia/métodos , Humanos , Razão Sinal-RuídoRESUMO
In the context of soft matter and cellular mechanics, microrheology - the use of micron-sized particles to probe the frequency-dependent viscoelastic response of materials - is widely used to shed light onto the mechanics and dynamics of molecular structures. Here we present the implementation of active microrheology in an Acoustic Force Spectroscopy setup (AFMR), which combines multiplexing with the possibility of probing a wide range of forces ( ~ pN to ~nN) and frequencies (0.01-100 Hz). To demonstrate the potential of this approach, we perform active microrheology on biological samples of increasing complexity and stiffness: collagen gels, red blood cells (RBCs), and human fibroblasts, spanning a viscoelastic modulus range of five orders of magnitude. We show that AFMR can successfully quantify viscoelastic properties by probing many beads with high single-particle precision and reproducibility. Finally, we demonstrate that AFMR to map local sample heterogeneities as well as detect cellular responses to drugs.
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Elasticidade , Eritrócitos , Fibroblastos , Reologia , Humanos , Viscosidade , Fibroblastos/fisiologia , Reologia/métodos , Colágeno/química , AcústicaRESUMO
The current treatment for oral inflammatory ulcerative diseases has limitations. In situ forming hydrogels have shown great potential to deliver therapeutic substances for drug delivery to the buccal cavity. This study aimed to prepare and characterize lipid- and surfactant-based mixed micelle in situ gel (MIG) and evaluate whether it can offer more favorable properties than the in situ gel for effective treatment of the disease. Dexamethasone was incorporated into the MIGs particles, based on Poloxamer 407 and chitosan. The lower gelation time at 37 â was considered a criterion to select superior formulations among the different lipid- and surfactant-based candidates. Further characterization was performed to evaluate the opted formulations regarding morphology, physical stability, rheology, texture, and release profile. All formulations were thermoresponsive and had a shorter gelation time as the temperature increased. Dexamethasone was released in a highly controlled manner, and morphological evaluation revealed that the mixed micelle in situ gels had spherical nanoparticles. Thixotropic behavior was observed in all MIGs, indicating a prolonged retention time of the formulation after oral administration. This study has shown that among different MIGs, the one with oleic acid is a more promising candidate than the in situ gel and other MIGs for drug delivery to the buccal cavity.
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Quitosana , Dexametasona , Sistemas de Liberação de Medicamentos , Liberação Controlada de Fármacos , Géis , Micelas , Poloxâmero , Dexametasona/administração & dosagem , Dexametasona/química , Quitosana/química , Géis/química , Sistemas de Liberação de Medicamentos/métodos , Poloxâmero/química , Tensoativos/química , Química Farmacêutica/métodos , Hidrogéis/química , Anti-Inflamatórios/administração & dosagem , Anti-Inflamatórios/química , Nanopartículas/química , Portadores de Fármacos/química , Reologia/métodos , Úlceras Orais/tratamento farmacológico , Administração Oral , Lipídeos/química , Ácido Oleico/químicaRESUMO
Unexpected cross-contamination by foreign components during the manufacturing and quality control of pharmaceutical products poses a serious threat to the stable supply of drugs and the safety of customers. In Japan, in 2020, a mix-up containing a sleeping drug went undetected by liquid chromatography during the final quality test because the test focused only on the main active pharmaceutical ingredient (API) and known impurities. In this study, we assessed the ability of a powder rheometer to analyze powder characteristics in detail to determine whether it can detect the influence of foreign APIs on powder flow. Aspirin, which was used as the host API, was combined with the guest APIs (acetaminophen from two manufacturers and albumin tannate) and subsequently subjected to shear and stability tests. The influence of known lubricants (magnesium stearate and leucine) on powder flow was also evaluated for standardized comparison. Using microscopic morphological analysis, the surface of the powder was observed to confirm physical interactions between the host and guest APIs. In most cases, the guest APIs were statistically detected due to characteristics such as their powder diameter, pre-milling, and cohesion properties. Furthermore, we evaluated the flowability of a formulation incorporating guest APIs for direct compression method along with additives such as microcrystalline cellulose, potato starch, and lactose. Even in the presence of several additives, the influence of the added guest APIs was successfully detected. In conclusion, powder rheometry is a promising method for ensuring stable product quality and reducing the risk of unforeseen cross-contamination by foreign APIs.
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Contaminação de Medicamentos , Pós , Reologia , Pós/química , Reologia/métodos , Contaminação de Medicamentos/prevenção & controle , Excipientes/química , Acetaminofen/química , Celulose/química , Preparações Farmacêuticas/química , Controle de Qualidade , Aspirina/química , Química Farmacêutica/métodos , Lactose/química , Composição de Medicamentos/métodos , Lubrificantes/química , Princípios AtivosRESUMO
INTRODUCTION: There are currently no clinical criteria for obstructed urinary flow after hypospadias repair surgery. Previous studies have utilized adult and pediatric nomograms and flow shapes to define obstruction, however these methods are limited by a lack of standardization and lack of interrater reliability when determining flow shapes, respectively. The idealized voider derived flow indexes offer a way to track uroflowmetry results in a volume and age agnostic manner. OBJECTIVE: We sought to evaluate all our hypospadias patients over a 10-year period and identify patients without complications and those with complications and determine their respective flow parameters. Our secondary objective is to identify which uroflowmetry parameters are the most significant predictors of urethral stricture and meatal stenosis at the time of the uroflowmetry study. STUDY DESIGN: Retrospective chart review was used to compile demographic information, details of hypospadias repair surgeries, and uroflowmetry results from pediatric hypospadias repair patients. Subjects were divided into distal, midshaft, and proximal groups based on the initial location of their urethral meatus. Flows from the hypospadias repair groups were compared to flows from normal age matched controls from a previous study. We compared flows from hypospadias repair patients with no complications present with those who had urethral stricture or meatal stenosis present at the time of uroflowmetry. Binary logistic regression and ROC analysis was used to assess different uroflowmetry parameters' ability to detect the presence of obstructed urine flow. RESULTS: 467 uroflowmetry studies from 200 hypospadias repair patients were included in the database. Compared to controls, the hypospadias repair groups tended to have significantly lower Qmax, Qavg, Qmax FI, Qavg FI, and longer ttQmax. Significant differences in flow parameters were observed when comparing hypospadias repair patients with and without flow obstructing complications at the time of uroflowmetry. Binary logistic regression including various uroflowmetry parameters showed Qmax FI had a significant effect on the odds of observing the absence of a stricture in proximal and distal hypospadias cases. DISCUSSION: Of the uroflowmetry parameters analyzed, binary logistic regression and the likelihood ratio of a positive result all point to Qmax FI as the better parameter to use to detect the presence of complications in patients who have undergone distal or proximal hypospadias repair surgery. CONCLUSION: We have established normal parameters for post-operative hypospadias repair patients which can be used to follow patients over time and allow for the identification of complications by keeping track of flow indexes which are volume and age agnostic.
Assuntos
Hipospadia , Urodinâmica , Hipospadia/cirurgia , Hipospadia/fisiopatologia , Humanos , Masculino , Estudos Retrospectivos , Urodinâmica/fisiologia , Pré-Escolar , Complicações Pós-Operatórias/etiologia , Complicações Pós-Operatórias/fisiopatologia , Complicações Pós-Operatórias/diagnóstico , Procedimentos Cirúrgicos Urológicos Masculinos/métodos , Lactente , Criança , Reologia/métodos , Estreitamento Uretral/cirurgia , Estreitamento Uretral/fisiopatologiaRESUMO
The USP Rotating Basket Dissolution Testing Apparatus 1 is listed in the USP as one of the tools to assess dissolution of oral solid dosage forms. Baskets of different mesh sizes can be used to differentiate between dissolution profiles of different formulations. Here, we used Particle Image Velocimetry (PIV) to study the hydrodynamics of the USP Apparatus 1 using baskets with different mesh openings (10-, 20- and 40-mesh) revolving at 100 rpm, when the vessel was filled with 500 mL. The velocity profiles throughout the liquid were found to vary significantly using baskets of different mesh sizes, typically increasing with increased size of the opening of the basket mesh, especially for axial and radial velocities. This, in turn, resulted in a significantly different flow rate through the basket, which can be expected to significantly impact the dissolution rate of the drug product. A comparison between the results of this work with those of a previous study with a 900-mL fill volume (Sirasitthichoke et al., Intern. J. Pharmaceutics, 2021, 607: 120976), shows that although the hydrodynamics in the USP Apparatus 1 changed with fill level in the vessel, the flow rate through the basket was not significantly affected. This implies that tablets dissolving in the two systems would experience similar tablet-liquid medium mass transfer coefficients, and therefore similar initial dissolution rates, but different dissolution profiles because of the difference in volume.
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Liberação Controlada de Fármacos , Hidrodinâmica , Reologia , Solubilidade , Comprimidos , Reologia/métodos , Composição de Medicamentos/métodos , Composição de Medicamentos/instrumentação , Química Farmacêutica/métodos , Tamanho da Partícula , Tecnologia Farmacêutica/métodosRESUMO
Estimating the elasticity of hydrogel phantoms in a cell culture plane is important for understanding the cell behavior in response to various types of mechanical stimuli. Hence, a noncontact tool for measuring the elastic properties of hydrogel phantoms in such three-dimensional cell cultures is required. A well-known method to determine the mechanical properties of hydrogels is the transient wave method. However, due to the multiple reflections of waves from the boundaries, a bigger cell culture plane or multiple directional filters may be required. In this study, we utilized reverberant shear wave elastography, which is based on the autocorrelation principle, to evaluate the shear wave speed in hydrogel samples within a culture dish. Numerical simulations were performed first to confirm the validity of the reverberant elastography method. Subsequently, we used this method to measure the wave speeds in hydrogel phantoms with different concentrations. Shear rheology tests were also performed, and their results were found to be in good agreement with the measured shear wave speeds. The proposed method could be useful for measuring the elasticity of tissues in tissue engineering applications in an inexpensive and noncontact manner.
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Técnicas de Imagem por Elasticidade , Hidrogéis , Imagens de Fantasmas , Hidrogéis/química , Técnicas de Imagem por Elasticidade/métodos , Elasticidade , Reologia/métodosRESUMO
In this study, we examine the behavior of articular cartilage equilibrated in a salt (NaCl) solution during non-Newtonian fluid flow that follows an Ostwald-de Waele model. A linearly elastic and isotropic rectangular strip of cartilage is considered for analysis. A continuum theory of mixtures has been employed to develop a coupled system of partial differential equations for the solid displacement and the fluid pressure by considering the important factor of the ion concentration by assuming the cartilage as a deformable porous media. The coupled system of partial differential equations is solved using the numerical method named method of lines. In most cases, shear-thinning fluid is compared to the shear-thickening fluid to magnify the difference. Graphical results show that shear-thickening fluids bring more solid deformation and shows less fluid pressure in comparison to the shear-thinning fluids.
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Cartilagem Articular , Pressão , Cartilagem Articular/fisiologia , Modelos Biológicos , Humanos , Íons , Animais , Reologia/métodos , Elasticidade , Cloreto de Sódio/química , Viscosidade , PorosidadeRESUMO
Viscoelastic transformation of tissue drives aberrant cellular functions and is an early biomarker of disease pathogenesis. Tissues scale a range of viscoelastic moduli, from biofluids to bone. Moreover, viscoelastic behavior is governed by the frequency at which tissue is probed, yielding distinct viscous and elastic responses modulated over a wide frequency band. Existing tools do not quantify wideband viscoelastic spectra in tissues, leaving a vast knowledge gap. We present wideband laser speckle rheological microscopy (WB-SHEAR) that reveals elastic and viscous response over sub-megahertz frequencies previously not investigated in tissue. WB-SHEAR uses an optical, noncontact approach to quantify wideband viscoelastic spectra in specimens spanning a range of moduli from low-viscosity fibrin to highly elastic bone. Via laser scanning, micromechanical imaging is enabled to access wideband viscoelastic spectra in heterogeneous tumor specimens with high spatial resolution (25 micrometers). The ability to interrogate the viscoelastic landscape of diverse biospecimens could transform our understanding of mechanobiological processes in various diseases.
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Elasticidade , Reologia , Viscosidade , Reologia/métodos , Humanos , Animais , Lasers , Microscopia/métodosRESUMO
Ultrasound coupling is one of the critical challenges for traditional photoacoustic (or optoacoustic) microscopy (PAM) techniques transferred to the clinical examination of chronic wounds and open tissues. A promising alternative potential solution for breaking the limitation of ultrasound coupling in PAM is photoacoustic remote sensing (PARS), which implements all-optical non-interferometric photoacoustic measurements. Functional imaging of PARS microscopy was demonstrated from the aspects of histopathology and oxygen metabolism, while its performance in hemodynamic quantification remains unexplored. In this Letter, we present an all-optical thermal-tagging flowmetry approach for PARS microscopy and demonstrate it with comprehensive mathematical modeling and ex vivo and in vivo experimental validations. Experimental results demonstrated that the detectable range of the blood flow rate was from 0 to 12â mm/s with a high accuracy (measurement error:±1.2%) at 10-kHz laser pulse repetition rate. The proposed all-optical thermal-tagging flowmetry offers an effective alternative approach for PARS microscopy realizing non-contact dye-free hemodynamic imaging.
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Técnicas Fotoacústicas , Tecnologia de Sensoriamento Remoto , Técnicas Fotoacústicas/métodos , Reologia/métodos , Ultrassonografia/métodos , Microscopia/métodosRESUMO
A goal of this study is to explore the difference in rheological properties of xanthan gum (XG)-based mixtures with gum arabic (GA) or GA-based emulsion (GAE). The stability of GAE was improved by thickening with XG. The intrinsic viscosity of all mixtures decreased as GA concentration increased, implying an XG conformational transition from the disordered to the ordered form. All mixtures except for an XG-GA mixture at 6.0 % GA attained a higher consistency index value than XG alone, indicating synergistic interactions between the components. At a high GA concentration (>3.0 %), the XG-GAE mixture showed higher relative apparent viscosity values than the XG-GA mixture. All mixtures except for an XG-GA mixture at 6.0 % GA showed higher elastic modulus and lower viscous modulus values than XG alone. Consequently, all mixtures showed lower tan δ values (0.26-0.30) than XG alone (0.31). Moreover, with a high GA concentration (>1.5 %), the XG-GAE mixtures achieved lower relative tan δ values than XG-GA mixture. These results indicate that XG formed a higher weak gel-like network with GAE than GA. Overall, the findings demonstrate that the interaction between XG and GA is influenced by conformational changes in the latter in both aqueous and emulsion systems.
Assuntos
Goma Arábica , Gomas Vegetais , Emulsões , Polissacarídeos Bacterianos , Viscosidade , Reologia/métodosRESUMO
The present study adopts a smartphone-based approach for the experimental characterization of coronary flows. Technically, Particle Tracking Velocimetry (PTV) measurements were performed using a smartphone camera and a low-power continuous wave laser in realistic healthy and stenosed phantoms of left anterior descending artery with inflow Reynolds numbers approximately ranging from 20 to 200. A Lagrangian-Eulerian mapping was performed to convert Lagrangian PTV velocity data to a Eulerian grid. Eulerian velocity and vorticity data obtained from smartphone-based PTV measurements were compared with Particle Image Velocimetry (PIV) measurements performed with a smartphone-based setup and with a conventional setup based on a high-power double-pulsed laser and a CMOS camera. Smartphone-based PTV and PIV velocity flow fields substantially agreed with conventional PIV measurements, with the former characterized by lower average percentage differences than the latter. Discrepancies emerged at high flow regimes, especially at the stenosis throat, due to particle image blur generated by smartphone camera shutter speed and image acquisition frequency. In conclusion, the present findings demonstrate the feasibility of PTV measurements using a smartphone camera and a low-power light source for the in vitro characterization of cardiovascular flows for research, industrial and educational purposes, with advantages in terms of costs, safety and usability.
Assuntos
Fenômenos Fisiológicos Cardiovasculares , Smartphone , Reologia/métodos , Velocidade do Fluxo Sanguíneo , Imagens de FantasmasRESUMO
BACKGROUND: The functioning of the thyroid gland is a multi-component process that in some conditions may undergo alterations. The thyroid gland is part of the endocrine system that produces the iodine-containing hormones thyroxine and triiodothyronine. Thyroid hormones, control metabolism and energy, growth processes, maturation of tissues and organs, regulation of blood flow, and, therefore, providing vital functions of the body. The role of thyroid hormones in the regulation of blood flow is determined by the intensity of their production and the quantity in the blood. Presumably, in case of oncological and non-oncological diseases of the thyroid gland, the fluidity of the blood, which depends on the rheological properties, will be different. OBJECTIVE: Our aim was investigating rheological characteristics for studying of changes of rheology in patients with thyrotoxicosis, with benign tumor pathology of the thyroid gland, with thyroid cancer and finding possible diagnostic markers for differentiating benign and malignant thyroid tumors. METHODS: In this regard, we examined, using modern methods accepted in clinical practice, a standard list of recommended diagnostic tests in the group of patients (thyrotoxicosis: nâ=â25; benign tumor: nâ=â47), thyroid cancer: nâ=â35) and control group (nâ=â15), and with new original methods, parameters that describe the rheological properties of the blood, such as blood rheological index, volume, thickness, surface area of erythrocytes, erythrocyte aggregation index, deformation index, plasma viscosity, hematocrits. RESULTS: Against the background of relative changes in the studied values, it is necessary to pay attention to the fact that erythrocyte aggregation in patients with a benign form and control, as well as in patients with a malignant form and control, differ significantly from each other, in addition, there is a significant difference between aggregation in the group of patients with benign and control aggregation. malignant forms of the disease. It is significant that aggregability differs in patients with thyrotoxicosis and in controls. This indicates that erythrocyte aggregation is particularly informative. The blood rheological index most clearly demonstrated the difference between benign and malignant forms of the disease. Significantly changed compared to control in various forms of thyroid diseases. CONCLUSION: Additional diagnostic markers for differentiating benign and malignant thyroid tumors may be consideredeerythrocyte aggregation index and blood rheological index.
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Neoplasias da Glândula Tireoide , Humanos , Neoplasias da Glândula Tireoide/sangue , Neoplasias da Glândula Tireoide/diagnóstico , Neoplasias da Glândula Tireoide/patologia , Masculino , Feminino , Pessoa de Meia-Idade , Diagnóstico Diferencial , Adulto , Hemorreologia , Tireotoxicose/diagnóstico , Tireotoxicose/sangue , Glândula Tireoide , Biomarcadores Tumorais/sangue , Idoso , Reologia/métodosRESUMO
This paper proposes an adaptive river discharge measurement method based on spatiotemporal image velocimetry (STIV) and optical flow to solve the problem of blurred texture features and limited measurement accuracy under complex natural environmental conditions. Optical flow tracking generates spatiotemporal images by following the flow mainstream direction of rivers with both regular and irregular natural banks. A texture similarity function filtering method effectively enhances spatiotemporal texture features. The proposed method is applied to a natural river, with measurement results from a propeller-type current meter used as truth values. It is evaluated and compared with three other methods regarding measurement accuracy, error, and other evaluation indices. The results demonstrate that the method significantly improves spatiotemporal image quality. Its estimation outcomes perform better across all evaluation metrics, enhancing the adaptability and accuracy of the flow measurement method.
Assuntos
Fluxo Óptico , Rios , Reologia/métodosRESUMO
The study aimed to optimize the ultrasonic-assisted modification (UAM) of corn and potato starch by assessing the influence of ultrasound geometry, power, and frequency on the fluid flow for sonicated starch to achieve porous starch with a higher degree of hydrolyzing by α-amylase. This assessment was conducted through mathematical modeling and 3D computational fluid dynamics (CFD) simulations. The ultrasonic pressure field is determined by the solution of the non-linear Westervelt equation in the frequency domain. Then, the obtained field is utilized to simulate the dissipated power and flow field characteristics. According to the results obtained from the Rapid Visco Analyzer (RVA), it was observed that the peak and final viscosity of hydrolyzed sonicated starch were less than hydrolyzed native starch. This decrease in viscosity indicates a breakdown of the starch structure, leading to a more fluid-like consistency. The shear rate and shear stress data are used for rheology modeling. The fluid's viscosity is represented based on three models of Herschel-Bulkley, Casson, and Power law (Ostwald-de Waele). The magnitude of yield shear stress at low shear rates, the shear-thinning behavior, and the nearly Newtonian fluid nature at high shear rates are extracted from the viscosity models. The surfaces of the starch granules were analyzed using scanning electron microscopy (SEM) revealed that sonication treatments caused damage, cracks, and porosity on the surfaces of the starch granules which were prone to amylolytic enzymes. This indicates that the structural integrity of the granules was compromised and facilitated enzyme penetration. This study proposes that ultrasonication can be utilized to produce damaged starch, which is susceptible to hydrolysis by α-amylase. This approach holds the potential for reducing enzyme consumption in various industries.