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To compare the effectiveness of positive pressure (PP) and negative pressure (NP) for reducing gas inclusions in biological tissues in preparation for acoustic imaging. Eighteen pieces of porcine liver in degassed saline were included in this study. For the PP group (n = 9 samples), a wristwatch waterproof tester was used to pressurize samples to 0.41 MPa (59 psi) for 10 min. For the NP group (n = 9 samples), a desiccator at −0.08 MPa (−12 psi) was used for 30 min. Backscatter coefficients (BSCs) were calculated over the central frequency range of the backscattered spectra and paired-samples t -tests were performed. Utilization of PP resulted in a decrease in BSC for all samples, indicating less gas post-PP (pre-PP −13.0 ± 4.3 dB [mean ± SD], post-PP −18.9 ± 5.0 dB, p =.001). Utilization of NP resulted in an increase in BSC for the majority of samples (pre-NP −14.6 ± 6.0 dB, post-NP −13.1 ± 5.3 dB, p =.177). Utilization of a simple PP chamber consistently resulted in a decrease in tissue gas, at lower pressures than previously reported. The vacuum method is ineffective, may result in a paradoxical increase in tissue gas, and may not be recommended for tissue degassing. [ABSTRACT FROM AUTHOR]

Objectives: To assess inter-platform reproducibility of ultrasonic attenuation coefficient (AC) and backscatter coefficient (BSC) estimates in adults with known/suspected nonalcoholic fatty liver disease (NAFLD).Methods: This HIPAA-compliant prospective study was approved by an institutional review board; informed consent was obtained. Participants with known/suspected NAFLD were recruited and underwent same-day liver examinations with clinical ultrasound scanner platforms from two manufacturers. Each participant was scanned by the same trained sonographer who performed multiple data acquisitions in the right liver lobe using a lateral intercostal approach. Each data acquisition recorded a B-mode image and the underlying radio frequency (RF) data. AC and BSC were calculated using the reference phantom method. Inter-platform reproducibility was evaluated for AC and log-transformed BSC (logBSC = 10log10BSC) by intraclass correlation coefficient (ICC), Pearson's correlation, Bland-Altman analysis with computation of limits of agreement (LOAs), and within-subject coefficient of variation (wCV; applicable to AC).Results: Sixty-four participants were enrolled. Mean AC values measured using the two platforms were 0.90 ± 0.13 and 0.94 ± 0.15 dB/cm/MHz while mean logBSC values were - 30.6 ± 5.0 and - 27.9 ± 5.6 dB, respectively. Inter-platform ICC was 0.77 for AC and 0.70 for log-transformed BSC in terms of absolute agreement. Pearson's correlation coefficient was 0.81 for AC and 0.80 for logBSC. Ninety-five percent LOAs were - 0.21 to 0.13 dB/cm/MHz for AC, and - 9.48 to 3.98 dB for logBSC. The wCV was 7% for AC.Conclusions: Hepatic AC and BSC are reproducible across two different ultrasound platforms in adults with known or suspected NAFLD.Key Points: • Ultrasonic attenuation coefficient and backscatter coefficient are reproducible between two different ultrasound platforms in adults with NAFLD. • This inter-platform reproducibility may qualify quantitative ultrasound biomarkers for generalized clinical application in patients with suspected/known NAFLD. [ABSTRACT FROM AUTHOR]

We report a "solo-solvent de novo liquid-phase" method of synthesizing a highly-favored sulfide electrolyte (Li6PS5Cl) for developing all-solid-state lithium batteries. The key chemistry for such a successful method is that tetrahydropyrrole enables in situ synthesis of the critical precursor Li2S from cheap and air-stable precursors of lithium chloride and sodium sulfide. [ABSTRACT FROM AUTHOR]

Abstract Untreated nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) lead to irreversible liver damage. We hypothesized that a low-fat diet (LFD) or a high-fat diet (HFD) with soy protein isolate (SPI) would be an effective intervention to halt or reverse NAFLD progression. To test these hypotheses, we conducted 2 studies. In the first study, we fed an HFD to 7-week-old C57BL/6J mice to induce NAFLD compared to an LFD (control). Hepatic steatosis was monitored by quantitative ultrasound (QUS) scans (in vivo and ex vivo). Animals were euthanized after 0, 2, 4, and 6 weeks of feeding. In the second study, 7-week-old mice were randomized onto an LFD or HFD with SPI intervention after 4 weeks of feeding HFD. Animals from each group were scanned with QUS and euthanized after 4, 9, and 12 weeks of feeding. Animals fed the HFD developed NAFLD (100%) and NASH (80%) characterized by increased liver weight, lipid accumulation, and histological scores for inflammation by 4 weeks in the first study. In the second study, the LFD ameliorated this NAFLD phenotype after 5 weeks of feeding; however, the SPI intervention failed to significantly attenuate NAFLD. QUS parameters were significantly increased with the HFDs (P <.05) and steatosis grade (P <.05) and were positively correlated with hepatic lipid concentrations. In conclusion, dietary modification may be effective at reversing NAFLD and NASH at early stages. Furthermore, QUS may become a valuable tool to track hepatic steatosis. Additional studies are needed to further evaluate the effectiveness of these interventions. [ABSTRACT FROM AUTHOR]

Objectives: To assess inter-sonographer reproducibility of ultrasound attenuation coefficient (AC), backscatter coefficient (BSC) and shear wave speed (SWS) in adults with known/suspected non-alcoholic fatty liver disease (NAFLD).Methods: The institutional review board approved this HIPAA-compliant prospective study; informed consent was obtained. Participants with known/suspected NAFLD were recruited and underwent same-day liver examinations with a clinical scanner. Each participant was scanned by two of the six trained sonographers. Each sonographer performed multiple data acquisitions in the right liver lobe using a lateral intercostal approach. A data acquisition was a single operator button press that recorded a B-mode image, radio-frequency data, and the SWS value. AC and BSC were calculated from the radio-frequency data using the reference phantom method. SWS was calculated automatically using product software. Intraclass correlation coefficient (ICC) and within-subject coefficient of variation (wCV) were calculated for applicable metrics.Results: Sixty-one participants were recruited. Inter-sonographer ICC was 0.86 (95% confidence interval: 0.77-0.92) for AC and 0.87 (0.78-0.92) for log-transformed BSC (logBSC = 10log10BSC) using one acquisition per sonographer. ICC was 0.88 (0.80-0.93) for both AC and logBSC averaging 5 acquisitions. ICC for SWS was 0.57 (0.29-0.74) using one acquisition per sonographer, and 0.84 (0.66-0.93) using 10 acquisitions. The wCV was ~7% for AC, and 19-43% for SWS, depending on number of acquisitions.Conclusions: Hepatic AC, BSC and SWS measures on a clinical scanner have good inter-sonographer reproducibility in adults with known or suspected NAFLD. Multiple acquisitions are required for SWS but not AC or BSC to achieve good inter-sonographer reproducibility.Key Points: • AC, BSC and SWS measurements are reproducible in adults with NAFLD. • Inter-sonographer reproducibility of SWS measurement improves with more acquisitions being averaged. • Multiple acquisitions are required for SWS but not AC or BSC. [ABSTRACT FROM AUTHOR]

In this study, we evaluated the utility of using high-frequency ultrasound to non-invasively track the degenerative process in a rat model of peripheral nerve injury. Primary analyses explored spatial and temporal changes in quantitative backscatter coefficient (BSC) spectrum-based outcomes and B-mode textural outcomes, using gray level co-occurrence matrices (GLCMs), during the progressive transition from acute to chronic injury. As secondary analyses, correlations among GLCM and BSC spectrum-based parameters were evaluated, and immunohistochemistry were used to suggest a structural basis for ultrasound outcomes. Both mean BSC spectrum-based and mean GLCM-based measures exhibited significant spatial differences across presurgical and 1-month/2-month time points, distal stumps enclosed proximity to the injury site being particularly affected. The two sets of parameters sensitively detected peripheral nerve degeneration at 1-month and 2-month post-injury, with area under the receiver operating charactersitic curve > 0.8 for most parameters. The results also indicated that the many BSC spectrum-based and GLCM-based parameters significantly correlate with each other, and suggested a common structural basis for a diverse set of quantitative ultrasound parameters. The findings of this study suggest that BSC spectrum-based and GLCM-based analysis are promising non-invasive techniques for diagnosing peripheral nerve degeneration. [ABSTRACT FROM AUTHOR]

The frequency-dependent ultrasonic backscatter coefficient (BSC) from tissues, a fundamental parameter estimated by quantitative ultrasound (QUS) techniques, contains microstructure information useful for tissue characterization. To extract the microstructure information from the BSC, the tissue under investigation is often modeled as a collection of discrete scatterers embedded in a homogeneous background. From a discrete scatterer point of view, the BSC is dependent on not only the properties of individual scatterers relative to the background but also the scatterer spatial arrangement [described by the structure function (SF)]. Recently, the 2-D SF was computed from histological tissue sections, and was shown to be related to the volumetric SF extracted from QUS measurements. In this paper, a stereological method is proposed to extract the volumetric (3-D) SF from 2-D histological tissue sections. Simulations and experimental cell pellet biophantom studies were conducted to evaluate the proposed method. Simulation results verified the proposed method. Experimental results showed that the volumetric SF extracted using the proposed method had a significantly better agreement with the QUS-extracted SF than did the 2-D SF extracted in the previous study. The proposed stereological approach provides a useful tool for predicting the SF from histology. [ABSTRACT FROM AUTHOR]

The purpose of this study is to evaluate the repeatability and reproducibility (R&R) of quantitative ultrasound (QUS) estimates, specifically attenuation coefficient (AC) and backscatter coefficient (BSC), using the same Siemens 3000 clinical ultrasound scanner. Additionally, the purpose of this work is to detail the measurement and analysis methodology. Repeatability is closeness of agreement between measures obtained with the same method under same conditions (same sonographer and same transducer) and reproducibility is closeness of agreement between measures obtained with the same method under different conditions (different sonographers and/or different transducers). Calibrated phantoms were scanned by two sonographers using two transducers in each session for multiple sessions over a period of four months. The phantom scans occurred as part of a clinical QUS liver study in human research participants spanning a spectrum of obesity and liver disease severity. The scanner was adjusted in each participant to obtain the highest quality liver B-mode images prior to acquiring data from the phantoms for which no scanner adjustments were made. The R&R were analyzed and estimated using the unweighted sums of squares ANOVA approach by applying two random effect models. The measurement variance caused by repeatability and reproducibility is small (AC: 2.4– 3.2\times 10^-4 [dB/cm-MHz]2; 10log10BSC: 0.23–0.27 dB^2 ). The reproducibility variance is statistically significantly lower than the repeatability variance. The total R&R was not influenced by phantom properties over a wide range representing those found in liver in vivo. [ABSTRACT FROM PUBLISHER]

Ultrasonic backscattering coefficient (BSC) has been used extensively to characterize tissue. In most cases, sparse scatterer concentrations are assumed. However, many types of tissues have dense scattering media. This study addresses the problem of dense media scattering by taking into account the correlation among scatterers using the structure functions. The effect of scatterer polydispersity on the structure functions is investigated. Structure function models based on polydisperse scatterers are theoretically developed and experimentally evaluated against the structure functions obtained from cell pellet biophantoms. The biophantoms were constructed by placing live cells of known concentration in coagulation media to form a clot. The BSCs of the biophantoms were estimated using single-element transducers over the frequency range from 11 to 105 MHz. Experimental structure functions were obtained by comparing the BSCs of two cell concentrations. The structure functions predicted by the models agreed with the experimental structure functions. Fitting the models yielded cell radius estimates that were consistent with direct light microscope measures. The results demonstrate the role of scatterer position correlation on dense media scattering, and the significance of scatterer polydispersity on structure functions. This work may lead to more accurate modeling of ultrasonic scattering in dense medium for improved tissue characterization. [ABSTRACT FROM AUTHOR]

In this paper, a new machine learning based framework is developed for the energy policy and operation management of the smart grids, utilizing advanced support vector networks in the renewable smart grids (RSGs), considering storage unit, wind and tidal systems and dispatchable units. The proposed system first develops a support vector regression (SVR) for prediction of the tidal and wind units output power with high accuracy. In the second step, an energy policy system is devised which forces the system operator to support renewable sources by guaranteeing the full purchase of their generation. In the third step, the optimal energy management framework is launched which optimizes the operation costs when considering the practical constraints. In the proposed novel framework, a new optimization method based on fuzzy dragonfly algorithm (FDA) is developed to enhance the search performance by creating adjusting fuzzy version this algorithm. In order to handle the uncertainty effects, a reduced scenario based approach is developed which shows high accuracy of 95% confidence level but with trivial computational time. The system quality is assessed on a test RSG system. The results prove the contributing claims of the research, clearly. [ABSTRACT FROM AUTHOR]

Simple scattering media fit scattering model theories much better than more complex scattering media. Tissue is much more complex as an acoustic scattering media and to date there has not been an adequate scattering model that fits it well. Previous studies evaluated the scattering characteristics of simple media (grouping of cells at various number densities) and fit them to the concentric spheres scattering model theory. This study is to increase the complexity of the media to provide insight into the acoustic scattering characteristics of tissue, and specifically two tumor types. Complementing the data from the tumors is 100% volume fraction cell pellets of the same cell lines. Cell pellets and ex vivo tumors are scanned using high-frequency single-element transducers (9-105 MHz), and the attenuation and backscatter coefficient (BSC) are estimated. BSC comparisons are made between cell pellets and tumors. The results show that the 4T1 (ATCC #CRL-2539) cell pellets and tumors have similar BSC characteristics, whereas the MAT (ATCC #CRL-1666) cell pellets and tumors have significantly different BSC characteristics. Factors that yield such differences are explored. Also, the fluid-filled sphere and the concentric spheres models are evaluated against the BSC characteristics, demonstrating that further work is required. [ABSTRACT FROM AUTHOR]

Ultrasound (US) is an increasingly prevalent and effective diagnostic modality for neuromuscular imaging. Gray-scale B-mode imaging has been the dominant US approach to evaluating nerves qualitatively or making morphometric measurements of nerves, providing important insights into pathological changes for conditions such as carpal tunnel syndrome. Among more recent ultrasound strategies, high-frequency ultrasound (often defined as >15 MHz for clinical applications), quantitative ultrasound and image textural analysis offer promising enhancements for improved and more objective approaches to nerve imaging. In this study, we evaluated the repeatability and reproducibility of backscatter coefficient (BSC) and imaging texture features extracted by gray-level co-occurrence matrices (GLCMs) in homogeneous tissue-mimicking reference phantoms and in median nerves in the wrists of healthy participants. We also investigated several practical sources of variability in the assessment of quantitative parameters, including influences of operators, and participant-to-participant variability. Overall, BSC- and GLCM-based outcomes are highly repeatable and reproducible after operator training, based on measurement of descriptive statistics, repeatability coefficient (RC) and reproducibility coefficient recommended by Quantitative Imaging Biomarker Alliance (QIBA RDC). GLCM parameters appear more reproducible and repeatable than BSC-based parameters in healthy participants in vivo. However, such variability noted here must be compared with the value ranges and variability of the results in pathological nerves, including median nerves afflicted by trauma, overuse syndromes such as carpal tunnel syndrome and after surgical repair. [ABSTRACT FROM AUTHOR]

Previous work estimated the ultrasonic backscatter coefficient (BSC) from low-concentration (volume density < 3%) Chinese Hamster Ovary (CHO, 6.7 -μm cell radius) cell pellets. This study extends the work to higher cell concentrations (volume densities: 9.6% to 63%). At low concentration, BSC magnitude is proportional to the cell concentration and BSC frequency dependency is independent of cell concentration. At high cell concentration, BSC magnitude is not proportional to cell concentration and BSC frequency dependency is dependent on cell concentration. This transition occurs when the volume density reaches between 10% and 30%. Under high cell concentration conditions, the BSC magnitude increases slower than proportionally with the number density at low frequencies (ka < 1), as observed by others. However, what is new is that the BSC magnitude can increase either slower or faster than proportionally with number density at high frequencies (ka > 1). The concentric sphere model least squares estimates show a decrease in estimated cell radius with number density, suggesting that the concentric spheres model is becoming less applicable as concentration increases because the estimated cell radius becomes smaller than that measured. The critical volume density, starting from when the model becomes less applicable, is estimated to be between 10% and 30% cell volume density. [ABSTRACT FROM AUTHOR]

A cell pellet biophantom technique is introduced, and applied to the ultrasonic backscatter coefficient (BSC) estimate using Chinese hamster ovary (CHO) cells. Also introduced is a concentric sphere scattering model because of its geometrical similarities to cells with a nucleus. BSC comparisons were made between the concentric sphere model and other well-understood models for mathematical verification purposes. BSC estimates from CHO cell pellet biophantoms of known number density were performed with 40 and 80 MHz focused transducers (overall bandwidth: 26-105 MHz). These biophantoms were histologically processed and then evaluated for cell viability. Cell pellet BSC estimates were in agreement with the concentric sphere model. Fitting the model to the BSC data yielded quantitative values for the outer sphere and inner sphere. The radius of the cell model was 6.8±0.7 μm; the impedance of the cytoplasm model was 1.63±0.03 Mrayl and the impedance of the nuclear model was 1.55±0.09 Mrayl. The concentric sphere model appears as a new tool for providing quantitative information on cell structures and will tend to have a fundamental role in the classification of biological tissues. [ABSTRACT FROM AUTHOR]

In the modern control schemes broadly applied presently in the servo drive system of machine tools, the sampling frequency has been growing larger and larger becomes higher and higher, so it is important to keep up-to-date with the variance of the actual system parameters. As a solution to the problem, a novel method developed from the recursive extended least squares (RELS) algorithm in terms of the computation of functions, operates in such a way that the parameters of the system model are revised only when several proper new groups of data are obtained. The simulation and experimentation of online direct closed-loop system identification indicate that, by selecting the updating step, this method is able to effectively cut down the identifying cost time while obtaining satisfactory accuracy of estimation. [ABSTRACT FROM AUTHOR]

Silicon is regarded as one of the most prospective anode candidates for the new generation of lithium ion batteries, because of its high theoretical specific capacity. Nevertheless, the huge expansion/contraction of silicon during cycling leads to rapid capacity decay. Herein, to suppress the concomitant mechanical damage, a composite material Si@B-C/rGO is prepared by in-situ encapsulating Si particles inside boron-doped carbon skeleton (B-C) and then loaded on reduced graphene oxide (rGO). The specific capacity of Si@B-C/rGO materials maintain at 1600 and 956 mAh g−1 after 100 cycles in liquid-phase and all-solid-state batteries, respectively. The performance improvement could be ascribed to main factors below: (i) The carbon shell significantly relieves expansion/contraction of silicon nanoparticles; (ii) The boron doping is conducive to the insertion/extraction of lithium-ions, because boron atoms have stronger affinity to lithium-ions than carbon; (iii) Loading Si@B-C nanoparticles on rGO can reduce particle agglomeration, and rGO provides a conductive network that ensures the transmission of lithium-ions. This work gives valuable reference to the design of advanced silicon-based anode materials to develop liquid and all-solid-state lithium-ion batteries. [Display omitted] • Si@B-C/rGO is prepared by in-situ encapsulating Si inside boron-doped carbon skeleton then loaded on reduced graphene oxide. • The introduction of boron into the carbon enhances Li+ adsorption and insertion behaviors, as verified by VASP calculations. • Loading Si@B-C nanoparticles on rGO can provides a conductive network that ensures the transmission of lithium-ions. • In liquid-phase and all-solid-state lithium-ion batteries, Si@B-C/rGO displays outstanding electrochemical performance. [ABSTRACT FROM AUTHOR]

We report a synthesis of lithium sulfide, the cost-determining material for making sulphide solid electrolytes (SSEs), via spontaneous metathesis reactions between lithium salts (halides and nitrate) and sodium sulfide. This innovative method is economical, scalable and green. It will pave the way to developing practical SSE-based solid-state lithium batteries. [ABSTRACT FROM AUTHOR]

In recent years, defective TiO2-based composite nanomaterials have received much attention in the field of photocatalysis. In this work, TiB2 was used as a precursor to successfully prepare Ti3+ defective TiO2 (TiO2-B) with a truncated bipyramidal structure by a one-step method. Then, the SnS2 nanosheets were assembled onto the as-prepared TiO2-B through simple hydrothermal reaction. TiO2-B exhibits strong visible light absorption properties, but the recombination rate of the photo-generated electron-hole pair was high and does not exhibit ideal photocatalytic performance. Upon introducing SnS2, the heterojunction catalyst SnS2-Ti3+ defective TiO2 (SnS2/TiO2-B) not only possesses the strong light absorption from UV to visible light region, the lowest photo-generated charge recombination rate but also achieves a more negative conduction band potential than the reduction potential of CO2 to CO, and thereby, exhibits the significantly enhanced selectivity and yield of CO in photocatalytic CO2 reduction. Notably, SnS2/TiO2-B produces CO at a rate of 58 µmol·h−1·g−1 with CO selectivity of 96.3% under visible light irradiation, which is 2 and 19 times greater than those of alone TiO2-B and SnS2, respectively. Finally, a plausible photocatalytic mechanism on SnS2/TiO2-B was proposed that the electron transfer between TiO2 and SnS2 follows the Z-scheme mode. Our results present an effective way to gain highly efficient TiO2 based photocatalysts for CO2 reduction by combining different modification methods of TiO2 and make full use of the synergistic effects. [ABSTRACT FROM AUTHOR]

Predicting women at risk for spontaneous pre-term birth (sPTB) has been medically challenging because of the lack of signs and symptoms of pre-term birth until interventions are too late. We hypothesized that prediction of the sPTB risk level is enhanced when using both historical clinical (HC) data and quantitative ultrasound (QUS) data compared with using only HC data. HC data defined herein included birth history prior to that of the current pregnancy as well as, from the current pregnancy, a clinical cervical length assessment and physical examination data. The study population included 248 full-term births (FTBs) and 26 sPTBs. QUS scans (Siemens S2000 and MC9-4) were performed by registered diagnostic medical sonographers using a standard cervical length approach. Two cervical QUS scans were conducted at 20 ± 2 and 24 ± 2 wk of gestation. Multiple QUS features were evaluated from calibrated raw radiofrequency backscattered ultrasonic signals. Two statistical models designed to determine sPTB risk were compared: (i) HC data alone and (ii) combined HC and QUS data. Model comparisons included a likelihood ratio test, cross-validated receiver operating characteristic area under the curve, sensitivity and specificity. The study's birth outcomes were only FTBs and sPTBs; medically induced pre-term births were not included. Combined HC and QUS data identified women at risk of sPTB with better AUC (0.68, 95% confidence interval [CI]: 0.57–0.78) compared with HC data alone (0.53, 95% CI: 0.40–0.66) and HC data + cervical length at 18–20 wk of gestation (average AUC = 0.51, 95% CI: 0.38–0.64). A likelihood ratio test for significance of QUS features in the classification model was highly statistically significant (p < 0.01). Even with only 26 sPTBs among 274 births, value was added in predicting sPTB when QUS data were included with HC data. [ABSTRACT FROM AUTHOR]

Lithium sulfide (Li 2 S) is an important material for lithium-sulfur batteries and solid-state batteries. However, its prohibitive price hinders the practical development of these technologies, reflecting multiple problems in existing production processes including high temperature/energy demands, greenhouse gas emissions, low yield, low purity and the use of air sensitive equipment. Herein we report the development of an environmentally friendly process for the scalable production of Li 2 S without need for a glove box. The net chemical process is the reaction between Li metal and hydrogen sulfide (H 2 S) with ethanol as the auxiliary solvent, which can in principle be recovered and recycled. The production capability reaches 1.0 kg_Li 2 S/day, 50–100 times greater than the largest scale reported in the literature. The material quality of the resulting Li 2 S is validated through its use as a cathode material in lithium-sulfur batteries, achieving essentially comparable performance with commercial Li 2 S. Moreover, additional value is provided by concomitant H 2 production which is demonstrated through its use for the in-situ reduction of copper oxide. We believe that the process described by this work can be readily adapted to support the developments of advanced batteries. [Display omitted] [ABSTRACT FROM AUTHOR]

Ultrasound ultrafast imaging (UI) allows acquisition of thousands of frames per second with a sustained image quality at any depth in the field of view. Therefore, it would be ideally suited to obtain good statistical sampling of fast-moving tissues using spectral-based techniques to derive the backscatter coefficient (BSC) and associated quantitative parameters. In UI, an image is formed by insonifying the medium with plane waves steered at different angles, beamforming them and compounding the resulting radiofrequency images. We aimed at validating, experimentally, the effect of these beamforming protocols on the BSC, under both isotropic and anisotropic conditions. Using UI techniques with a linear array transducer (5–14 MHz), we estimated the BSCs of tissue-mimicking phantoms and flowing porcine blood at depths up to 35 mm with a frame rate reaching 514 Hz. UI-based data were compared with those obtained using single-element transducers and conventional focusing imaging. Results revealed that UI compounded images can produce valid estimates of BSCs and effective scatterer size (errors less than 2.2 ± 0.8 and 0.26 ± 0.2 dB for blood and phantom experiments, respectively). This work also describes the use of pre-compounded UI images ( i.e ., steered images) to assess the angular dependency of circulating red blood cells. We have concluded that UI data sets can be used for BSC spectral tissue analysis and anisotropy characterization. [ABSTRACT FROM AUTHOR]

Ultrasound localization microscopy (ULM) is an emerging vascular imaging technique that overcomes the resolution-penetration compromise of ultrasound imaging. Accurate and robust microbubble (MB) localization is essential for successful ULM. In this study, we present a deep learning (DL)-based localization technique that uses both Field-II simulation and in vivo chicken embryo chorioallantoic membrane (CAM) data for training. Both radio frequency (RF) and in-phase and quadrature (IQ) data were tested in this study. The simulation experiment shows that the proposed DL-based localization was able to reduce both missing MB localization rate and MB localization error. In general, RF data showed better performance than IQ. For the in vivo CAM study with high MB concentration, DL-based localization was able to reduce the vessel MB saturation time by more than 50% compared to conventional localization. In addition, we propose a DL-based framework for real-time visualization of the high-resolution microvasculature. The findings of this article support the use of DL for more robust and faster MB localization, especially under high MB concentrations. The results indicate that further improvement could be achieved by incorporating temporal information of the MB data. [ABSTRACT FROM AUTHOR]

This article evaluated the repeatability and reproducibility (R&R) of quantitative ultrasound (QUS) biomarkers attenuation coefficient (AC) and backscatter coefficient (BSC) in transvaginal QUS reference phantoms for obstetric applications. Five phantoms were scanned by three sonographers according to the scanning protocol. Each sonographer scanned each phantom with four transvaginal transducers of the same model (MC9-4) and three probe cover types (latex cover, nonlatex cover, and no cover). The AC and BSC were estimated by using a reference phantom method. The R&R analysis was performed for the frequency-averaged AC and logBSC (= 10log10BSC) (5.4–5.8 MHz) by using three-factor random effects Analysis of Variance with interaction. The total R&R variabilities for AC and logBSC are small (AC: 0.042–0.065 dB/cm-MHz; logBSC: 0.50–0.68 dB), indicating high measurement precision. These values are small compared to the ranges of AC (0.28–0.99 dB/cm-MHz) and logBSC (−33.16 to −20.35 dB) of the five phantoms. The AC and logBSC biomarkers measured on transvaginal QUS phantoms using the reference phantom method are repeatable, and reproducible between sonographers, transducers, and probe covers. [ABSTRACT FROM AUTHOR]

The aim of the present study was to investigate the protective role of hyperoxia liquid in regulating cardiopulmonary bypass (CPB)‑induced myocardial damage and its possible underlying mechanism. In the CPB‑induced rat model, hyperoxia liquid enhanced left ventricular ejection fraction (LVEF), reduced the left ventricular internal dimension systole (LVIDs) level, inhibited malondialdehyde levels, increased superoxide dismutase, glutathione (GSH) and GSH peroxidase levels, suppressed heart cell apoptosis, and induced the nuclear factor erythroid 2‑related factor 2 (Nrf2) and heme oxygenase‑1 (HO‑1) signaling pathway. Then, ML385, a Nrf2 inhibitor, was used to attenuate the effect of hyperoxia liquid on LVEF and LVIDs levels, oxidative stress and heart cell apoptosis in the CPB‑induced rat model. Collectively, the results of the present study demonstrated that the protective role of hyperoxia liquid may regulate oxidative stress in a CPB‑induced rat model through the Nrf2‑antioxidant response element signaling pathway. [ABSTRACT FROM AUTHOR]