Search

Objective: Ultrasound elasticity imaging is a class of ultrasound techniques with applications that include the detection of malignancy in breast lesions. Although elasticity imaging traditionally assumes linear elasticity, the large strain elastic response of soft tissue is known to be nonlinear. This study evaluates the nonlinear response of breast lesions for the characterization of malignancy using force measurement and force-controlled compression during ultrasound imaging. Methods: 54 patients were recruited for this study. A custom force-instrumented compression device was used to apply a controlled force during ultrasound imaging. Motion tracking derived strain was averaged over lesion or background ROIs and matched with compression force. The resulting force-matched strain was used for subsequent analysis and curve fitting. Results: Greater median differences between malignant and benign lesions were observed at higher compressional forces (p-value < 0.05 for compressional forces of 2-6N). Of three candidate functions, a power law function produced the best fit to the force-matched strain. A statistically significant difference in the scaling parameter of the power function between malignant and benign lesions was observed (p-value = 0.025). Conclusions: We observed a greater separation in average lesion strain between malignant and benign lesions at large compression forces and demonstrated the characterization of this nonlinear effect using a power law model. Using this model, we were able to differentiate between malignant and benign breast lesions. Significance: With further development, the proposed method to utilize the nonlinear elastic response of breast tissue has the potential for improving non-invasive lesion characterization for potential malignancy.

Photocatalysts in powdered form have been extensively researched for their ability to decontaminate various pollutants. However, the use of photocatalytic nanoparticles in real-world applications faces several challenges, including a tendency to clump together and issues with separating and reclaiming them. Of the various strategies for securing nanoparticles to a substrate, photocatalytic coatings have emerged as a promising solution to overcome the common limitations associated with powdered forms. The process of plasma electrolytic oxidation (PEO) was employed to create oxide layers on aluminum (Al), thereby improving its surface attributes for photocatalytic activity (PA). An analysis was conducted on the morphological, structural, and optical features of the PEO coatings to comprehend their influence on the performance of photocatalysis. This review focuses on summarizing the key aspects of the PEO process, including its impact on the PA. It specifically examines various parameters such as electrolyte composition, additives, deposition time, and electrical parameters, considering the substrate’s chemical composition. The findings show that the PEO coatings display superior photocatalytic properties, which can be ascribed to their distinctive surface shape and crystalline arrangement. There was an increase in light absorption and the efficiency of charge separation, suggesting that PEO coatings could be promising for effective photocatalysis. This study offers valuable perspectives on the creation and enhancement of PEO coatings on Al bases for enduring photocatalytic uses, presenting potential paths for environmental cleanup and solar energy transformation.

Background: COVID-19 pandemic has currently no vaccines. Thus, the only feasible solution for prevention relies on the detection of COVID-19-positive cases through quick and accurate testing. Since artificial intelligence (AI) offers the powerful mechanism to automatically extract the tissue features and characterise the disease, we therefore hypothesise that AI-based strategies can provide quick detection and classification, especially for radiological computed tomography (CT) lung scans. Methodology: Sixmodels, two traditional machine learning (ML)-based (k-NN and RF), two transfer learning (TL)-based (VGG19 and InceptionV3), and the last two were our custom-designed deep learning (DL) models (CNN and iCNN), were developed for classification between COVID pneumonia (CoP) and non-COVID pneumonia (NCoP). K10 cross-validation (90% training: 10% testing) protocol on an Italian cohort of 100 CoP and 30 NCoP patients was used for performance evaluation and bispectrum analysis for CT lung characterisation. Results: Using K10 protocol, our results showed the accuracy in the order of DL > TL > ML, ranging the six accuracies for k-NN, RF, VGG19, IV3, CNN, iCNN as 74.58 ± 2.44%, 96.84 ± 2.6, 94.84 ± 2.85%, 99.53 ± 0.75%, 99.53 ± 1.05%, and 99.69 ± 0.66%, respectively. The corresponding AUCs were 0.74, 0.94, 0.96, 0.99, 0.99, and 0.99 (p-values < 0.0001), respectively. Our Bispectrum-based characterisation system suggested CoP can be separated against NCoP using AI models. COVID risk severity stratification also showed a high correlation of 0.7270 (p< 0.0001) with clinical scores such as ground-glass opacities (GGO), further validating our AI models. Conclusions: We prove our hypothesis by demonstrating that all the six AI models successfully classified CoP against NCoP due to the strong presence of contrasting features such as ground-glass opacities (GGO), consolidations, and pleural effusion in CoP patients. Further, our online system takes < 2 s for inference.

High-purity porous nanostructured silicon particles were successfully produced from quartzite rock via the multi-step processing route including primary acid leaching of crashed quartzite feedstock, wet blending of quartzite and magnesium powder, reduction, and final multi-stage hydrometallurgical purification of the products. Laboratory-grade silica was also treated for comparison. The effect of silica purity, reactants’ molar ratios (Mg:SiO2), and hydrometallurgical refining on reaction products were investigated and discussed through the results of X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM) equipped with energy dispersive spectroscopy (EDS) and inductively coupled plasma-mass spectrometry (ICP-MS). The results indicated that the combination of primary acid treatment, combustion synthesis in controlled atmosphere, and final special acid leaching process is an efficient route for the production of porous nanostructured elemental silicon particles with a uniform structure that can be used in several applications in the energy sector with or without further processing.

To prospectively evaluate the diagnostic performance of 3‐dimensional (3D) shear wave elastography (SWE) for assessing thyroid nodules. A total of 176 surgically or cytologically confirmed thyroid nodules (63 malignant and 113 benign) in 176 patients who had undergone conventional ultrasound (US), 2‐dimensional (2D) SWE, and 3D SWE examinations were included in this study. Quantitative elasticity values (mean elasticity, maximum elasticity, and standard deviation of elasticity of a large region of interest and mean elasticity of a 2‐mm region of interest) were measured on 2D and 3D SWE. Diagnostic performances of conventional US, 2D SWE, and 3D SWE were assessed. The role of 2D and 3D SWE in reducing unnecessary fine‐needle aspiration (FNA) for nodules with low suspicion was also evaluated. The diagnostic performances in terms of the area under the receiver operating characteristic curve were 0.612 for conventional US, 0.836 for 2D SWE (P< .001 in comparison with conventional US), and 0.839 for 3D SWE (P< .001 in comparison with conventional US). The mean elasticity achieved the highest diagnostic performance in 2D SWE, whereas the standard deviation of elasticity achieved the highest performance in 3D SWE, although no significant difference was found between them (P> .05). Three‐dimensional SWE increased the specificity in comparison with 2D SWE (88.5% versus 82.3%; P= .039). For the 37 nodules with low suspicion on conventional US imaging, 2D SWE was able to avoid unnecessary FNA in 77.1% (27 of 35) of benign nodules, and 3D SWE further increased the number to 88.6% (31 of 35). Three‐dimensional SWE is a useful tool for predicting thyroid nodule malignancy and reducing unnecessary FNA procedures in thyroid nodules with low suspicion of malignancy.

Hydromechanical deep drawing (HMDD) is a sheet hydroforming process to produce complex workpieces with high drawing ratio. Fluid pressure used during the forming process is one of the most effective parameters in this process in which increasing critical pressure causes to rupture occurrence. Since the material properties in different angles respect to the rolling direction affect the amount of critical pressure, it is important to develop an appropriate theoretical model for prediction of plastic behavior of material with high precision. In this paper, a theoretical model based on BBC2008 yield criterion including 8 and 16 parameters (8p and 16p) is developed to determine critical pressure in HMDD process. With applying uniaxial and equi-biaxial tensile tests and optimizing an error-function by using Levenberg—Marquardt method, the parameters of BBC2008 yield criterion can be determined. Low carbon St14 steel sheets are utilized for experimental samples to verify critical pressure obtained from the proposed theoretical model. BBC2008 model with 8p and 16p is compared with Barlat—Lian 1989 and experiments. The results show that BBC2008-16p yield criterion can provide a more precise model of material behavior in planar anisotropy properties, while BBC2008-8p yield criterion have a better prediction of rupture occurrence in HMDD process.

In this paper, a theoretical model was proposed to stress analysis and calculate the critical fluid pressure path corresponding to rupture instability in hydro-mechanical deep drawing (HMDD) of hemi-prolate spheroid (HPS) cups. This model is based on Barlat and Lian yield criterion and maximum drawing force condition was utilized to rupture instability analysis. The effects of material and process parameters were investigated on critical fluid pressure path. The results demonstrated that maximum permissible fluid pressure is increased by enhancement of sheet thickness, strain hardening exponent, anisotropy and reduction of friction coefficient. Decrease the difference between semi-major and semi-minor axis of the hemi-prolate spheroid, enlarges safe zone. Finally, a serial of HMDD experiments were accomplished to verify the theoretical critical fluid pressure path. Theoretical results agree well with experimental data.

The shear-induced deformation of a capsule with a stiff nucleus, a model of eukaryotic cells, is studied numerically. The membrane of the cell and of its nucleus are modelled as a thin elastic material obeying a Neo-Hookean constitutive law. The fluid–structure coupling is obtained using an immersed boundary method. The variations induced by the presence of the nucleus on the cell deformation are investigated when varying the viscosity ratio between the inner and outer fluids, the membrane elasticity and its bending stiffness. The deformation of the eukaryotic cell is smaller than that of the prokaryotic one. The reduction in deformation increases for larger values of the capillary number. The eukaryotic cell remains thicker in its middle part compared to the prokaryotic one, thus making it less flexible to pass through narrow capillaries. For a viscosity ratio of 5, the deformation of the cell is smaller than in the case of uniform viscosity. In addition, for non-zero bending stiffness of the membrane, the deformation decreases and the shape is closer to an ellipsoid. Finally, we compare the results obtained modelling the nucleus as an inner stiffer membrane with those obtained using a rigid particle.

The performance degradation of air electrodes in solid oxide cells is strongly affected by impurities such as sulfur dioxide. Filtration is a practical approach for proton-exchange membrane fuel cells with high air purity demands. This study aims to evaluate the applicability of such a filter consisting of specially modified activated carbons for the LSCF air electrode. Different air quality qualities were used to differentiate degradation mechanisms caused by ambient air impurities from the intrinsic aging of a cell. Analyzing the impedance spectra using a distribution of relaxation times (DRT) and a complex nonlinear least squares fit (CNLS) revealed a significant degradation rate in the first 360 hours. Filtering the air reduces the degradation rate significantly. A similar degradation of cell performance occurs in cleaned air as in synthetic air, indicating the ability of the filter material to prolong the lifetime of SOCs through the adsorption of gas impurities.

Perovskites show high potential as alternative fuel electrodes in solid oxide electrolysis cells (SOECs) due to their high chemical stability, high conductivity, good catalytic activity and cost-effectiveness. In this work, four perovskites (strontium-iron-niobate double perovskite (SFN), strontium-iron-titanate (STF), lanthanum-strontium-titanate (LST), and lanthanum-strontium-iron-manganese (LSFM)) were examined as fuel electrode materials for SOECs. First, the chemical stability of the perovskites in a reducing atmosphere and the reactivity between the electrode and electrolyte material were analyzed. Besides featuring good chemical stability under reducing conditions, SFN double perovskite and LST exhibit the lowest interaction with the electrolyte (yttria-stabilized zirconia, 8YSZ) after thermal treatment. The results indicate a need for a barrier layer between the tested electrode materials and the YSZ electrolyte to achieve sufficient cell performance throughout its operation in the electrolysis mode. After thoroughly evaluating all preliminary tests, STF was chosen for the first subsequent electrochemical tests. Initial impedance measurements of symmetrical electrolyte-supported cells consisting of pure STF-based electrodes with and without a barrier layer between the electrodes and the electrolyte were conducted to obtain a base for further optimization. For the 5STF fuel electrode, the obtained EIS data confirm the conclusion from the reactivity experiments. Applying a barrier layer at the 5STF fuel electrode/ electrolyte interface is needed to reduce the cell´s ohmic and polarization resistances.

Isoproterenol (ISPR) is an important catecholamine-based drug that is widely used in the treatment of heart disease. However, overdose of this drug is very dangerous to the human body. In this study, a new sensor based on a pyrogallol red modified-multiwalled carbon nanotube paste electrode (PGRMMWCNTPE) was prepared and used for high sensitivity determination of ISPR in aqueous solution. Electrocatalytic oxidation of ISPR at the PGRMMWCNTPE was investigated by chronoamperometry, cyclic voltammetry, and square-wave voltammetry. The values of the catalytic rate constant, electron transfer coefficient, and diffusion coefficient for ISPR oxidation were then calculated using voltammetric data. A linear calibration curve was constructed for ISPR concentration in the range 0.8–570 μmol/L with a detection limit of 0.47 μmol/L ISPR. The sensor was then applied to the determination of ISPR in urine and drug samples with satisfactory results.

In this paper, a theoretical framework was developed to incorporate BBC 2008 advanced yield criterion into the classical Marciniak–Kuczynski theory to compute limit strains of anisotropic metallic sheets. The classical Hill’s 48 yield function was also utilized to compare with the results obtained by BBC 2008. The anisotropy parameters contained in BBC 2008 yield function were identified by minimizing an error function using Levenberg–Marquardt method. The data from uniaxial and plane strain tensile testings were employed to establish the error function. All the experimental tests were performed on AA 3003-H19 aluminum sheets. The yield criteria were assessed from the standpoint of predicting material properties and the yield locus by comparing theoretical findings and experimental data. The influence of the use and non-use of the plane strain yield stresses in the identification procedure on the FLD calculation was also investigated. To verify the theoretical predictions of the FLD, a series of Nakajima tests were accomplished. Comparing the experimental results and theoretical predictions revealed that the best agreement was found when BBC 2008-16p yield function was utilized to express the yield locus. Failure to use the plane strain yield stresses in the calibration procedure of the BBC 2008-16p criterion also causes overpredicting the limit strains for positive strain ratios.

Around the world, wetland vulnerability to sea‐level rise (SLR) depends on different factors including tidal regimes, topography, creeks and estuary geometry, sediment availability, vegetation type, etc. The Plum Island estuary (PIE) is a mesotidal wetland system on the east coast of the United States. This research applied a newly updated Hydro‐MEM (integrated hydrodynamic‐marsh) model to assess the impacts of intermediate‐low (50 cm), intermediate (1 m), and intermediate‐high (1.5 m) SLR on marsh evolution by the year 2100. Model advancements include capturing vegetation change, inorganic and below and aboveground organic matter portion of marsh platform accretion, and mudflat creation. Although the results indicate a low vulnerability marsh at the PIE, the vegetation changes from high to low marsh under all SLR scenarios (2%–22%), with the higher bounds belonging to higher rise scenarios. Lower SLR produces more productive marsh (13% gain in high productivity regions), whereas the highest SLR scenario causes increased tidal inundation, which leads to loss in productivity (12% change from high to low productivity regions), generation of mudflats (17% of the domain land), and marsh migration to higher lands. Sensitive nonlinear tidal flow changes, which may be increased or decreased with SLR as a result of mudflat creation, marsh migration, and bottom friction change, emphasize the importance of integrated modeling approaches that include dynamic marsh feedbacks in hydrodynamic modeling and varying hydrodynamic effects on the marsh system. Plum Island mesotidal marsh system adapts itself to most of the sea‐level rise (SLR) scenarios but will undergo changes in vegetation typeLower SLR scenarios are favorable for Plum Island estuary marsh productivity but higher SLR results in low marsh dominance, mudflat creation, and migrationIntegrated modeling that couples biological feedbacks and hydrodynamics is critical to capture flow dynamics Plum Island mesotidal marsh system adapts itself to most of the sea‐level rise (SLR) scenarios but will undergo changes in vegetation type Lower SLR scenarios are favorable for Plum Island estuary marsh productivity but higher SLR results in low marsh dominance, mudflat creation, and migration Integrated modeling that couples biological feedbacks and hydrodynamics is critical to capture flow dynamics

A highly sensitive electrochemical sensor was prepared for the determination of L-cysteine using a modified multiwall carbon nanotubes paste electrode in the presence of 3,4-dihydroxycinnamic acid (3,4-DHCA) as a mediator, based on an electrocatalytic process. The results indicate that the electrode is electrocatalytically efficient for the oxidation of L-cysteine in the presence of 3,4-DHCA. The interaction between the mediator and L-cysteine can be used for its sensitive and selective determination. Using chronoamperometry, the catalytic reaction rate constant was calculated to be 2.37 × 102mol−1L s−1. The catalytic peak current was linearly dependent on the L-cysteine concentration in the range of 0.4–115 μmol/L. The detection limit obtained by linear sweep voltammetry was 0.25 μmol/L. Finally, the modified electrode was examined as a selective, simple, and precise new electrochemical sensor for the determination of L-cysteine in real samples.

The main purpose of this study is to develop a sensitive and selective modified carbon-paste electrode (CPE) with multiwall carbon nanotubes (MWCNTs) for the determination of 6-mercaptopurine (6-MP) in the presence of methyldopa (MD) as a mediator. Electrochemical methods, such as cyclic voltammetry, double step chronoamperometry and square wave voltammetry (SWV), used to study the characterization of the proposed modified electrode. The results show that MD can catalyze the oxidation of 6-MP in aqueous solution. Also, the catalytic rate constant (k), and diffusion coefficient (D) for 6-MP were estimated. The pick currents of 6-MP increased linearly with concentration in the ranges of 0.31–550 μmol L-1, with detection limit of 0.1 μmol L-1. The relative standard deviation (RSD %) for seven replicate measurements of 0.7 μmol L-1 6-MP was 1.6%. The prepared electrode is successfully applied for the voltammetric determination of 6-MP in pharmaceutical and biological samples.

A new vinylferrocene modified-multiwalled carbon nanotubes paste electrode was prepared and used for the determination of N-acetylcysteine (N-AC) and folic acid (FA). Using the modified electrode, a highly selective square wave voltammetric method for the simultaneous determination of N-AC and FA was developed. The peak currents of N-AC and FA increased linearly with their concentration in the ranges of 0.1–662 and 10.0–900 μmol L−1, respectively, with corresponding detection limits of 0.09 and 7.0 μmol L−1. The RSD% for 0.7 μmol L−1N-AC was 1.5%, whereas for 15.0 μmol L−1FA, it was 1.9%. Well separated oxidation peaks of N-AC and FA were obtained at pH 7.0 with this modified electrode. The modified electrode was successfully applied for the simultaneous determination of N-AC plus FA in real samples.

In recent years, several new techniques based on the radiation force of ultrasound have been developed. Vibroacoustography is a speckle-free ultrasound based imaging modality that can visualize normal and abnormal soft tissue through mapping the acoustic response of the object to a harmonic radiation force induced by ultrasound. In vibroacoustography, the ultrasound energy is converted from high ultrasound frequencies to a low acoustic frequency (acoustic emission) that is often two orders of magnitude smaller than the ultrasound frequency. The acoustic emission is normally detected by a hydrophone. In medical imaging, vibro-acoustography has been tested on breast, prostate, arteries, liver, and thyroid. These studies have shown that vibro-acoustic data can be used for quantitative evaluation of elastic properties. This paper presents an overview of vibro-acoustography and its applications in the areas of biomedicine.

Vibro-acoustography has gained interest in the recent years as a new modality for medical imaging. This method is based on low-frequency vibrations induced in the object by the radiation force of ultrasound. This paper focuses on potential applications of vibro-acoustography in breast imaging, including detection of microcalcifications, detection of arterial calcifications, and soft tissue imaging. In addition, we will briefly discuss our recent results of in vivo breast vibro-acoustography. Future developments and potential impact of vibro-acoustography in breast imaging are also discussed.

A sensitive electrochemical sensor for the determination of cysteamine was developed using a modified multiwall carbon nanotube paste electrode with isoproterenol as a mediator.

A simple and rapid flow injection spectrophotometric method has been developed for the determination of amount of thiocyanate in wastewaters and well water samples. It is based on the reaction of thiocyanate in hydrochloric acid with janus green and bromate. Reaction was monitored spectrophotometrically by measuring janus green absorbance at 𝜆max=554 nm. The calibration graph was linear over the range 0.02–1.0 μg mL−1 and the detection limit was 0.016 μg mL−1 (𝑠/𝑛=3). The throughput was 25 samples per hour.

A simple flow injection colorimetric procedure for determining phenylhydrazine was established. It is based on the reaction of phenylhydrazine in sulfuric acid with thionin and sodium nitrite. Reaction was monitored spectrophotometrically by measuring thionin absorbance at 𝜆max=602 nm. A standard or sample solution was injected into the sulfuric acid stream, which was then merged with sodium nitrite stream and thionin stream. Optimum conditions for determining phenylhydrazine were investigated by univariate method. Under the optimum conditions, a linear calibration graph was obtained over the range 0.05–0.60 μmol L−1, and the detection limit was 0.027 μmol L−1(𝑠/𝑛=3). The proposed method has been satisfactorily applied to the determination of phenylhydrazine in human serum and water samples.