Tracking Imaging Research Articles

The effect of 6-month treatment with coenzyme Q10 on endothelial, vascular and myocardial function in patients with nonalcoholic fatty liver disease

Abstract Background Patients with Non-alcoholic fatty liver disease (NAFLD) hold an increased cardiovascular risk and present impaired markers of vascular, endothelial and myocardial function. Coenzyme Q10 (CQ10) is a powerful antioxidant that enhances mitochondrial function. Patients/methods: 52 patients (52±10 years old) with NAFLD were randomized to 240 mg CQ10 (n=25) or placebo (n=27). We measured at baseline and at six months post-treatment: i) Perfused boundary Region (PBR) of the sublingual arterial microvessels (Microscan, Glycocheck), ii) Carotid femoral pulse wave velocity - PWV (Complior ALAM), iii) Flow-mediated dilation (FMD) of the brachial artery, iv) Global left ventricular longitudinal strain (GLS) by speckle tracking imaging, v) Controlled attenuation parameter (CAP) measurement (FibroScan, Echosens). Results Six months post treatment with cQ10, values of PBR (2.12±0.19 vs. 2.28±0.23 μm), PWV (9.5±2.3 vs. 10.5±2.4m/s), CAP score (278.1±50, 2 vs. 305.3±44.5dB/m), FMD (6.61±4 vs. 5.02±2.6 %) and GLS (-19.3±1.9 vs -18.2±2 %) were improved (p<0.05 for all comparisons). On the contrary, the patients who were treated with placebo did not show statistically significant differences in PBR, PWV, CAP score, FMD and GLS after from 6 months (p>0.05). In the patients who received cQ10, the percentage reduction of CAP score at 6 months was directly proportional to the percent reduction in PWV (r=0.31, p=0.045) and inversely proportional to the percentage increase in FMD (r=-0.58, p=0.014). Conclusion Six-month treatment with CoQ10 reduces liver steatosis in patients with NAFLD. CoQ10 is associated with improved endothelial, vascular and LV myocardial function in patients with NAFLD.

Decreased left atrial volume and preserved left atrial function in children with congenital Zika syndrome

Abstract Introduction The infection caused by Zika virus during pregnancy leads to congenital Zika syndrome (CZS). In a previous study of our group, we found that the heart is smaller in children with CZS, with few functional alterations. Left atrial strain imaging enables quantitative assessment of left atrial function, and recently its application has also shown promise in the pediatric population. Purpose To evaluate left atrial function in children affected by CZS, using echocardiogram and speckle tracking imaging technique. Methods This observational study was conducted with children with CZS using a two-dimensional speckle tracking technique to measure left atrial reservoir strain (LAS-r), conduit strain (LAS-cd), and contraction strain (LAS-ct). Also, to investigate the relationship between LAS-r and systolic excursion of the septum and lateral mitral annular plane (MAPSE), left atrial volume index and E/e’ ratio. Results A total of 52 patients were included, the median age of the studied population was 5 years (3 to 6), 59.6% male, and the body surface area was 0.66 [0.51, 0.90]. In the echocardiographic evaluation the left atrium volume index (ml/m²) was 13.15 [6.80, 18.00], considered smaller by the reference value. Also, the LAS-r (%) was 40.99 [24-70.5], LAS-cd (%) was 30,94 [32.5-52.5], LAS-cd (%) was 10,91 [5.2-24], values considered normal by the literature. Lateral MAPSE (cm) was 1.25 [0.81, 1.86] and septal MAPSE (cm) was 0.98 [0.78, 1.66] and E/e' ratio was 7.52 [4.57, 10.78]. A positive linear correlation was found between LAS-r and lateral MAPSE (r = 0.51, P = 0.019). Conclusion This original study with children with CZS shows that despite reduced atrial volume, the left atrial function remains normal, and correlates with left ventricular function evaluated by MAPSE. Further studies are needed to prospectively analyze the follow-up of left atrial morphology and function in this population.

Assessment of right ventricular dysfunction in breast cancer patients undergoing anthracycline and trastuzumab treatment

Abstract Background Anthracyclines and trastuzumab continue to be within the most popular systemic agents used in breast cancer treatment. Nonetheless, their cardiotoxic effects contribute to significant morbidity and mortality, which have been extensively studied and acknowledged. Left ventricular impairment and remodeling due to chemo- and target-therapy induced cardiotoxicity has been well described. However, effects on right ventricular function have not been fully elucidated and are incompletely understood. Purpose We aim to comprehensively assess right ventricular function in breast cancer patients before and during treatment with anthracyclines and trastuzumab. Methods We prospectively evaluated echocardiographic right ventricle (RV) parameters in 160 women (median age 48, IQR 43.00 - 57.00) diagnosed with breast cancer undergoing treatment with doxorubicin, trastuzumab or its combination. These patients were referred to a national cardiac reference centre to assess cancer therapy related cardiovascular dysfunction (CTRCD) risk. Two-dimensional echocardiography with speckle tracking imaging of left ventricle (LV) and RV was performed at baseline, 3 and 6 months. Right ventricular function was assessed with tricuspid annular plane systolic excursion (TAPSE), S’wave of the tricuspid annulus (S'), fractional area change (FAC), and free wall strain (RV-FWS). We designed a composite variable of right ventricular dysfunction constituted by any decrease in systolic function as evidenced by standard cutoff values of TAPSE, FAC, S’wave and RV-FWS. Descriptive statistics were calculated. Categorical values were compared using either the Fisher’s exact test or Chi-squared test and differences between means were assessed with the Kruskal-Wallis test or the Wilcoxon test as appropriate. Results TAPSE and S’ were significantly reduced from baseline, at 3 and 6 months, respectively (TAPSE: 21.62 ± 2.22, 21.00 ± 1.83, 20.72 ± 1.99, P=<0.001; S’:12.16 ± 1.91, 11.70 ± 1.76, 11.51 ± 1.53, P = 0.012) (Table 1). There were no significant changes in right ventricular echocardiographic parameters comparing patients with and without CTRCD, nevertheless, a notable proportion in both groups was observed (see Table 2). Conclusions There is a progressive decline in right ventricular systolic function over treatment with anthracyclines and trastuzumab. Even though RV dysfunction does not significantly differ between patients with or without cardiotoxicity, the high proportion observed highlights the need for comprehensive echocardiographic assessments.

Refined Coseismic Slip and Afterslip Distributions of the 2021 Mw 6.1 Yangbi Earthquake Based on GNSS and InSAR Observations

On 21 May 2021, an Mw 6.1 earthquake occurred in Yangbi County, Dali Bai Autonomous Prefecture, Yunnan Province, with the epicenter located in an unmapped blind fault approximately 7 km west of the Weixi-Qiaohou fault (WQF) on the southeastern margin of the Qinghai–Tibetan Plateau. While numerous studies have been conducted to map the coseismic slip distribution by using the Global Navigation Satellite System (GNSS), Interferometric Synthetic Aperture Radar (InSAR) and seismic data as well as their combinations, the understanding of deformation characteristics during the postseismic stage remains limited, mostly due to the long revisiting time interval and large uncertainty of most SAR satellites. In this study, we refined coseismic slip and afterslip distributions with nonlinear inversions for both fault geometry and relaxation time. First, we determined the fault geometry and coseismic slip distribution of this earthquake by joint inversion for coseismic offsets in the line-of-sight (LOS) direction of both Sentinel-1A/B ascending and descending track images and GNSS data. Then, the descending track time series of Sentinel-1 were further fitted using nonlinear least squares to extract the coseismic and postseismic deformations. Finally, we obtained the refined coseismic slip and afterslip distributions and investigated the spatiotemporal evolution of fault slip by comparing the afterslip with aftershocks. The refined coseismic moment magnitude, which was of Mw 6.05, was smaller than Mw 6.1 or larger, which was inferred from our joint inversion and previous studies, indicating a significant reduction in early postseismic deformation. In contrast, the afterslip following the mainshock lasted for about six months and was equivalent to a moment release of an Mw 5.8 earthquake. These findings not only offer a novel approach to extracting postseismic deformation from noisy InSAR time series but also provide valuable insights into fault slip mechanisms associated with the Yangbi earthquake, enhancing our understanding of seismic processes.

EthoWatcher OS: improving the reproducibility and quality of categorical and morphologic/kinematic data from behavioral recordings in laboratory animals.

Behavioral recordings annotated by human observers (HOs) from video recordings are a fundamental component of preclinical animal behavioral models of neurobiological diseases. These models are often criticized for their vulnerability to reproducibility issues. Here, we present the EthoWatcher-Open Source (EW-OS), with tools and procedures for the use of blind-to-condition categorical transcriptions that are simultaneous with tracking, for the assessment of HOs intra- and interobserver reliability during training and data collection, for producing video clips of samples of behavioral categories that are useful for observer training. The use of these tools can inform and optimize the performance of observers, thus favoring the reproducibility of the data obtained. Categorical and machine vision-derived outputs are presented in an open data format for increased interoperability with other applications, where behavioral categories are associated frame-by-frame with tracking, morphological and kinematic attributes of an animal's image. The center of mass (X and Y pixel coordinates), the animal's area in square millimeters, the length and width in millimeters, and the angle in degrees were recorded. It also assesses the variation in each morphological descriptor to produce kinematic descriptors. While the initial measurements are in pixels, they are later converted to millimeters using the scale calibrated by the user via the graphical user interfaces. This process enables the creation of databases suitable for machine learning processing and behavioral pharmacology studies. EW-OS is constructed for continued collaborative development, available through an open-source platform, to support initiatives toward the adoption of good scientific practices in behavioral analysis, including tools for evaluating the quality of the data that can alleviate problems associated with low reproducibility in the behavioral sciences.

Optical coherence tomography enables longitudinal evaluation of cell graft-directed remodeling in stroke lesions.

Stem cell grafting can promote glial repair of adult stroke injuries during the subacute wound healing phase, but graft survival and glial repair outcomes are perturbed by lesion severity and mode of injury. To better understand how stroke lesion environments alter the functions of cell grafts, we employed optical coherence tomography (OCT) to longitudinally image mouse cortical photothrombotic ischemic strokes treated with allogeneic neural progenitor cell (NPC) grafts. OCT angiography, signal intensity, and signal decay resulting from optical scattering were assessed at multiple timepoints across two weeks in mice receiving an NPC graft or an injection of saline at two days after stroke. OCT scattering information revealed pronounced axial lesion contraction that naturally occurred throughout the subacute wound healing phase that was not modified by either NPC or saline treatment. By analyzing OCT signal intensity along the coronal plane, we observed dramatic contraction of the cortex away from the imaging window in the first week after stroke which impaired conventional OCT angiography but which enabled the detection of NPC graft-induced glial repair. There was moderate, but variable, NPC graft survival at photothrombotic strokes at two weeks which was inversely correlated with acute stroke lesion sizes as measured by OCT prior to treatment, suggesting a prognostic role for OCT imaging and reinforcing the dominant effect of lesion size and severity on graft outcome. Overall, our findings demonstrate the utility of OCT imaging for both tracking and predicting natural and treatment-directed changes in ischemic stroke lesion cores.

Single-molecule tracking technology based on symmetric power exponential phases.

We present a design approach for a symmetric power exponential phase, resulting in a phase-modulated point-spread function with two symmetrical mainlobes that can be steered toward the optical axis opposite the x axis. This design offers nanoscale 3D localization capabilities suitable for 3D single-molecule tracking and localization imaging. The axial probing depth of this symmetric power exponential point-spread function can be adjusted as needed by manipulating specific parameters. Optimization of the symmetric power exponential phase involves truncation filtering to reduce sidelobes and the utilization of a phase inversion-based optimization algorithm to enhance transfer function efficiency and localization precision. A successful multi-molecule 3D tracking experiment was conducted at a 10 µm axial depth using a numerical aperture of 1.4 to validate the efficacy of the proposed design methodology.

Spatial resolution studies using point spread function extraction in optically read out Micromegas and GEM detectors

Optically read out gaseous detectors are used in track reconstruction and imaging applications requiring high granularity images. Among resolution-determining factors, the amplification stage plays a crucial role and optimizations of detector geometry are pursued to maximize spatial resolution. To compare Micro Pattern Gaseous Detector (MPGD) technologies, focused low-energy X-ray beams at the SOLEIL synchrotron facility were used to record and extract point spread function widths with MICRO-Mesh Gaseous Structure (icromegas) and Gas Electron Multiplier (GEM) detectors. Point spread function width of ≈108µm for Micromegas and ≈127µm for GEM foils were extracted. The scanning of the beam with different intensities, energies and across the detector active region can be used to quantify resolution-limiting factors and improve imaging detectors using MPGD amplification stages.

Tracking and fast imaging of a moving object via Fourier modulation

Tracking and fast imaging of a moving object via Fourier modulation

3D track extraction from a fluorescent nuclear track detector via machine learning and an application to diagnostics of laser-driven ions.

We have developed an ion diagnostic method for laser-driven ion acceleration experiments that uses fluorescent nuclear track detectors (FNTDs). An FNTD records the particle tracks as color centers and does not require chemical etching, unlike CR-39 track detectors. The color centers are observed using a confocal laser microscope, and 3D particle tracks can be obtained by changing its focal position. The intensity of the color centers corresponds to the energy deposited by the ions. The nuclides of the ions can be determined from the intensity distribution of the color centers as a function of depth and the distance between the stopping point and the surface of the detector. To extract the intensity distribution, we must track the same ion tracks in the depth-layered microscopic images from the surface to the stopping point, even if they overlap with those of other ions. In addition, since an FNTD is sensitive not only to ions but also to electrons and photons, we must identify ion tracks among those from the latter particles. To analyze a statistical number of ion tracks, it is necessary to automate these processes. We have thus developed a method for automated ion detection and 3D tracking that relies on a support vector classifier and a kernelized correlation filter. This method was tested on a laser ion acceleration experiment performed using the J-KAREN-P laser. The method automatically detects ion tracks on FNTDs and tracks them in the depth direction. The training data are sampled from the Heavy-Ion Medical Accelerator in Chiba.

Amino-Acid-Encoded Supramolecular Nanostructures for Persistent Bioluminescence Imaging of Tumor.

Bioluminescence imaging (BLI) is a powerful technique for noninvasive monitoring of biological processes and cell transplantation. Nonetheless, the application of D-luciferin, which is widely employed as a bioluminescent probe, is restricted in long-term in vivo tracking due to its short half-life. This study presents a novel approach using amino acid-encoded building blocks to accumulate and preserve luciferin within tumor cells, through a supramolecular self-assembly strategy. The building block platform called Cys(SEt)-X-CBT (CXCBT, with X representing any amino acid) utilizes a covalent-noncovalent hybrid self-assembly mechanism to generate diverse luciferin-containing nanostructures in tumor cells after glutathione reduction. These nanostructures exhibit efficient tumor-targeted delivery as well as sequence-dependent well-designed morphologies and prolonged bioluminescence performance. Among the selected amino acids (X = Glu, Lys, Leu, Phe), Cys(SEt)-Lys-CBT (CKCBT) exhibits the superior long-lasting bioluminescence signal (up to 72h) and good biocompatibility. This study demonstrates the potential of amino-acid-encoded supramolecular self-assembly as a convenient and effective method for developing BLI probes for long-term biological tracking and disease imaging.

The Relationship Between Right Ventricular Longitudinal Strain and Adverse Outcome in Hypertensive Patients: 10-year Follow-up.

Previous studies showed the importance of right ventricular (RV) remodeling in patients with arterial hypertension and RV longitudinal strain was recognized as very sensitive parameter for detection of subtle cardiac impairment. However, its clinical importance in arterial hypertension has not been established so far. The present study aimed to evaluate the association between RV longitudinal strain (global and free-wall) on adverse outcomes measured by MACE in the large group of hypertensive patients who were followed for mean period of 10 years. This retrospective study finally included 544 hypertensive patients who underwent full echocardiographic examination including 2D speckle tracking imaging. between January 2010 and December 2014. MACE was considered as the primary outcome and it was defined by all-cause mortality, cardiovascular mortality, myocardial infarction, coronary artery by-pass, coronary stent implantation, stroke, development of heart failure, and occurrence of atrial fibrillation during follow-up. Patients who experienced MACE were older than those who did not. There was no difference in demographic and clinical parameters between MACE and non-MACE patients. There was no difference in RV diameter, but MACE patients had higher RV wall thickness. RV systolic function parameters were similar between the two groups. RV global and free-wall longitudinal strain were significantly lower in MACE patients (-22.3 ± 3.6 vs. -24.7 ± 3.9%, p < 0.001 and - 25.8 ± 4.2 vs. -28.1 ± 4.5%, p < 0.001; respectively). Reduced RV GLS [OR 1.10; 95%: 1.02-1.20] and reduced RV free-wall longitudinal strain [OR 1,21; 95%CI: 1.05-1.39] were independently of clinical and echocardiographic parameters related with adverse outcome measured by MACE. RV GLS and RV free-wall longitudinal strain were independently related with adverse outcomes during 10-year follow-up in initially uncomplicated hypertensive patients.

Assessing Left Atrial Appendage Functions by Transesophageal Echocardiography and Speckle Tracking Imaging to Predict Recurring Atrial Fibrillation Post-Radiofrequency Catheter Ablation.

To predict recurring atrial fibrillation (AF) following radiofrequency catheter ablation by assessing the attributes of the left atrium and the left atrial (LA) appendage (LAA) using transesophageal echocardiography (TEE) and speckle tracking imaging. The structural and functional indices of the LA and LAA of 80 patients with AF who underwent preoperative transthoracic echocardiography and TEE were measured. Recurrence was recorded postoperatively at 3, 6, and 12 months. The independent determinants of recurring AF were identified by logistic regression, and their optimum cutoff values, sensitivity, and specificity were estimated from the receiver operating characteristic (ROC) curves. The recurrent and nonrecurrent groups comprised 17 and 63 patients, respectively. The LA internal diameter, LA end-diastolic and end-systolic volumes, LAA length, diameter and area of the opening of the LAA, and LAA end-diastolic volume were higher in the recurrent group. The LA strain in the reservoir phase, the ejection fraction and filling velocity of the LAA, the LAA emptying velocity (LAAeV), and the LAA strain (LAAS) reduced considerably. Multifactorial regression analyses demonstrated that the LAAeV and LAAS were independent determinants of recurring AF. ROC curve analysis revealed that the LAAeV and LAAS predicted postoperative recurrence at 34.5cm/s (area under the curve [AUC]: 0.954, sensitivity: 94.1%, and specificity: 92.1%) and 11.61% (AUC: 0.925, sensitivity: 82.4%, and specificity: 95.2%), respectively, while the AUC, sensitivity, and specificity of the combined predictors (LAAeV+LAAS) were 0.978, 94.1%, and 93.7%, respectively. The LAAeV and LAAS independently influenced the postoperative recurrence of AF.

Assessment of Left Ventricular Functional Impairment in Patients With Chronic Kidney Disease Using Three-Dimensional Speckle Tracking Imaging.

Chronic kidney disease (CKD) is strongly linked to the incidence and mortality of cardiovascular diseases (CVDs), with left ventricular myocardial damage being the most prevalent. This study aimed to assess left ventricle (LV) dysfunction using three-dimensional speckle tracking imaging (3D-STI) in CKD patients. A total of 110 CKD patients and 55 healthy volunteers underwent echocardiography. CKD patients were divided into CKD1 group and CKD2 group based on the estimated glomerular filtration rate (eGFR). Assessing cardiac function via two-dimensional speckle tracking echocardiography (2D-STE) and three-dimensional speckle tracking echocardiography (3D-STE) parameters, with strain presented in absolute terms. Collecting and comparing clinical and echocardiographic parameters from three groups, assessing 3D-STI's value in evaluating LV functional impairment in CKD patients via correlation and receiver operating characteristic (ROC) curve analyses, and identifying risk factors for CKD progression to end-stage renal disease (ESRD) through univariate and multivariate analyses. In CKD2 group, 2D-left ventricular ejection fraction (LVEF), 3D-LVEF, 2D left ventricular global longitudinal strain (2D-LVGLS), 3D-LVGLS, and 3D-left ventricular global circumferential peak strain (LVGCS) significantly worsen compared to the control and CKD1 groups, with statistically significant distinctions between the latter two (all p < 0.05). The absolute value of 3D-LVGLS shows a robust correlation with N-terminal pro-B-type natriuretic peptide (NT-proBNP) and serum creatinine (Scr) (r = -0.598, -0.649, both p < 0.001). ROC curve analysis indicates higher diagnostic efficacy of 3D-LVGLS and 3D-LVGCS for LV systolic function than 2D-LVGLS. Univariate and multivariate analyses reveal an independent association of 3D-LVGLS with the progression to ESRD in CKD. 3D-LVGLS and 3D-LVGCS effectively detect LV dysfunction in CKD patients. Specifically, 3D-LVGLS demonstrates a robust correlation with NT-proBNP and Scr and is independently linked to CKD progressing to ESRD.

The Predictive Value of Global Longitudinal and Circumferential Strains in Hypertensive Patients: 10-Year Follow-Up

Background: The aim of the current study was to investigate the predictive value of a multidirectional LV strain on adverse outcomes in a large population of uncomplicated hypertensive patients who were followed for a mean period of 10 years. Methods: This retrospective study included 591 recently diagnosed hypertensive patients who underwent clinically indicated echocardiography between January 2010 and December 2014 and were followed for a mean period of 10 years. Global longitudinal, circumferential and radial strains (GLS, GCS and GRS) were measured by 2D speckle tracking imaging. The primary outcome was a MACE occurrence defined by all-cause mortality, cardiovascular mortality, myocardial infarction, coronary artery by-pass, coronary stent implantation, stroke, development of heart failure and the occurrence of atrial fibrillation during follow-up. Results: Our results showed that GLS, GCS and GRS were significantly lower in patients who experienced MACE. Age, male gender, systolic blood pressure, left ventricular hypertrophy (LVH) and left atrial enlargement (LAE) were associated with MACE occurrence. Reduced GLS [OR 1.15; 95%CI: 1.01–1.30] and reduced GCS [OR 1.1; 95%CI: 1.02–1.22] were related with MACE independently of clinical characteristics, LV systolic and diastolic function, as well as LVH. Reduced GRS was not independently associated with adverse outcomes. Conclusions: Reduced GLS and GCS were independently associated with adverse outcomes during 10-year follow-up in patients who were recently diagnosed and uncomplicated hypertensive patients at the baseline.

Evaluation of Cardiac Function Recovery in Patients with Paroxysmal Atrial Fibrillation after Catheter Radiofrequency Ablation Using Two-Dimensional Speckle Tracking Imaging and Real-Time Three-Dimensional Echocardiography

Introduction: The aim of this study was to evaluate the utility of 2D-STI and real-time three-dimensional echocardiography (RT-3DE) in assessing changes in left atrial (LA) structure and function in patients with paroxysmal atrial fibrillation (PAF) post-radiofrequency catheter ablation (RFCA). Methods: A retrospective analysis was conducted on 44 PAF patients who underwent RFCA at BA Hospital from March 2022 to March 2023. An age- and gender-matched control group of 32 healthy individuals was also included. Comprehensive echocardiographic parameters including LA dimensions (LAAPD, LALRD), volumes (LAVmin, LAVmax), ejection fraction (LAEF), and tissue velocities (a’, Ar) were compared between groups. Post-RFCA changes in these parameters were also assessed at 1, 3, and 6 months. Results: Pre-RFCA, PAF patients demonstrated larger LA dimensions and volumes with reduced LAEF and tissue velocities compared to controls. Post-RFCA, there was a significant improvement in LAEF and left ventricular ejection fraction at 1, 3, and 6 months, with the most pronounced changes observed at 6 months. LA dimensions increased initially but then decreased from 1 to 6 months post-RFCA. Notably, strain rate (SRS, SRE, SRA) measurements in various LA segments improved progressively, with the most significant enhancements at 6 months, suggesting improved atrial mechanics. Conclusion: The application of 2D-STI and RT-3DE provides a quantitative means to evaluate the structural and functional changes in the LA of PAF patients following RFCA. The progressive improvements in LA dimensions, volumes, and strain measurements up to 6-month post-RFCA indicate the potential of these techniques in monitoring treatment efficacy and patient recovery.

Experimental study on tribological behavior of a binderless cemented carbide at high contact stress

Knowledge of frictional evolution and associated damage mechanism during sliding wear conditions using binderless WC-based cemented carbide is lacking. In this study, the frictional evolution and corresponding transformation of microstructure, and wear mechanisms of Al2O3/WC-based cemented carbide due to the effect of different contact pressure, especially high pressure have been explored using a reciprocating ball-on-flat sliding wear tester, which was experimentally simulated following the ASTM G133–02 standard. The dynamic curves in friction coefficient with the sliding time were described. The microscopic 3D topography of contact surface was obtained by the MFP-3D atomic force microscope. The material removal and the wear rate were discussed. Worn surface morphologies at different moments, cross-sectional images of wear tracks at different loads, and wear debris were taken by field emission scanning electron microscope. The results suggested that the pressure plays a decisive role in frictional evolution and wear characteristics. Two models of frictional evolution were declared. A novel “surge” phenomena in friction coefficient was found and explained at high contact pressure. Wear transition from mild wear to severe wear was confirmed. More than one wear mechanism was observed, including micro-cutting (polishing), generation and propagation of cracks, cracking-induced spalling, plastic deformation, and the formation of tribolayer.

Assessment of Carotid Artery Vibrations by Using Optical Flow Methods on Ultrasound Images and Optical Flow

Purpose: This study aims to extract carotid wall vibrations non-invasively and evaluate changes in the carotid artery caused by age, BMI, and sex. Such evaluation can increase the possibility of detecting wall stiffness and atherosclerosis in the early stages and prevent heart attack and death. Materials and Methods: To extract small vibrations of the carotid wall, the image-tracking method, and optical flow with four different methods were used. The study involved twenty participants, comprising six females and fourteen males, with a mean age of 36.25 years, mean weight of 75.2 Kg, and mean BMI of 25. The posterior wall motion and vibration were extracted using ultrasound RF signals. Results: 4 optical flow methods, Gunnar-Farneback, Horn- Schunk, Lucas-Kanade, and Lucas-Kanade derivative were used for all samples, and covariance, correlation, P-value, and R-squared were estimated. Results showed the differences in parameters such as age and BMI with carotid wall vibration. These values for age are (Cov = -0.1891, Corr = -0.6770, P-value &lt; 0.001, r2 = -0.4590) and for BMI are (Cov = -0.0564, Corr = -0.6510, P-value &lt; 0.001, r2 = 0.4238), respectively. For gender as a new parameter, a comparison between men’s and women’s vibrations was estimated. The range of measured vibrations by optical flow methods is about 0.0002 µm to 0.1µm, and the mean standard deviation is 0.04967 µm. Conclusion: The results presented that gender affects the vibration of the vessel wall, which in men is more than in women. In addition, increasing age and BMI may increase the stiffness of the carotid wall and reduce vibrations that were evaluated previously. Using the Gunner-Farneback method as image tracking for small vibrations is the best way with the highest accuracy.

Gelatin-coated glutathione depletion and oxygen generators in potentiated chemotherapy for pancreatic cancer

Chemotherapy is generally acknowledged as an effective method for pancreatic cancer (PC). However, its treatment efficacy is often compromised due to inefficient drug delivery and drug resistance propensity of tumor tissues. The purpose of this study is to design and develop a novel drug delivery system (Manganese-doped mesoporous silica nanoparticles, Mn-MSN) in which paclitaxel (PTX), a conventional chemotherapeutic agent used to effectively treat pancreatic cancer clinically. Through cross-linking with glutaraldehyde, gelatin (Ge) was encapsulated on the carrier surface, endowing the nanoparticles (Ge-Mn-MSN@PTX) with excellent biocompatibility, low hemolytic activity, and enzyme-responsive degradation. Mn was added for the following purposes: (1) catalyzing hydrogen peroxide (H2O2) to generate oxygen (O2), thereby alleviating tumor hypoxia and drug resistance; (2) depleting glutathione (GSH), inducing intracellular lipid peroxidation and ferroptosis; (3) enabling real-time monitoring of the therapeutic efficacy of the nanoparticles via magnetic resonance imaging (MRI). The experimental results demonstrated that Ge-Mn-MSN@PTX has satisfactory biosafety, antitumor activity, controlled drug release as well as imaging tracking capabilities. In the SW1990 nude mice model, the Ge-Mn-MSN@PTX effectively inhibited tumor growth by suppressing the expression of the resistance protein P-glycoprotein (P-gp) and inducing ferroptosis. In conclusion, the designed gelatin-coated Mn-MSN shows potential for application in future pancreatic cancer therapy.

Retraction Note: Human motion image detection and tracking method based on gaussian mixture model combined with light sensor

Retraction Note: Human motion image detection and tracking method based on gaussian mixture model combined with light sensor