Search Results (104,610)

Background: Accumulating evidence suggests that cannabidiol (CBD) exerts variable effects on cancer cells that influence cellular activity, including growth. While anecdotal evidence abounds, mechanistic studies have lagged. Methods: Malme-3M cells derived from melanoma and less-aggressive BJ fibroblast cells were incubated with CBD. CE-MS mass spectroscopy was used to measure metabolite changes resulting from CBD treatment. Results: Data indicate a differential response between malignant Malme-3M cells and BJ fibroblasts with respect to metabolites critical for primary metabolic function. A significant reduction in TCA metabolites is seen with a corresponding increase in glycolytic output in the Malme-3M cell line. A similar reduction in TCA activity in BJ fibroblasts appears to differentially activate fatty acid oxidation. ATP is significantly reduced in the Malme-3M cells with a corresponding decrease in metabolites associated with redox maintenance. Conclusions: This is the first metabolomics analyses of malignant Malme-3M cells and less-aggressive BJ fibroblasts after pre-treatment with CBD. The data suggest that the CBD-induced metabolic perturbation could reprogram cellular metabolism and affect ATP production and redox maintenance of the more-aggressive Malme-3M cells. Full article

Piezoelectric synthetic jet actuators typically struggle to generate high-speed jets at low driving frequencies due to the coupling effect between jet frequency and jet intensity. This limitation to some extent restricts their application in flow control within low-speed flow fields. To address this issue, this study presents two methods of signal modulation. The effects of driving signal modulation on dual synthetic jet actuator (DSJA) characteristics were experimentally investigated. A laser displacement meter was used to measure the central point amplitude of the piezoelectric diaphragm, while the velocity at the exit of the DSJAs was measured using a hot-wire anemometer. The effects of signal modulation on the amplitude of the piezoelectric diaphragm, the maximum jet velocity, and the frequency domain characteristics of the dual synthetic jet (DSJ) were thoroughly analyzed. Experimental results demonstrate that driving signal modulation can enhance jet velocity at relatively low driving frequencies. The modulated DSJ exhibits low-frequency characteristics, rendering it suitable for flow control applications that require low-frequency jets. Furthermore, the coupling effect between jet frequency and jet intensity in the piezoelectric DSJA is significantly alleviated. Starting from the vibration displacement of the piezoelectric transducer (PZT), this paper systematically elaborates on the corresponding relationship between PZT displacement and the peak velocity at the jet outlet, and the “low-frequency and high-momentum jet generation method based on signal modulation” proposed herein is expected to break through the momentum–frequency coupling limitation of traditional piezoelectric dual-stenosis jet actuators (DSJAs) and enhance their application potential in low-speed flow control. Full article

Motion artifacts (MA) are a key factor affecting the accuracy of a measured arterial pulse signal at rest. This paper presents a generalized time–frequency method for MA removal that is built upon a single-degree-of-freedom (SDOF) model of MA, where MA is manifested as time-varying system parameters (TVSPs) of the SDOF system for the tissue–contact-sensor (TCS) stack between an artery and a sensor. This model distinguishes the effects of MA and respiration on the instant parameters of harmonics in a measured pulse signal. Accordingly, a generalized SDOF-model-based time–frequency (SDOF-TF) method is developed to obtain the instant parameters of each harmonic in a measured pulse signal. These instant parameters are utilized to reconstruct the pulse signal with MA removal and extract heart rate (HR) and respiration parameters. The method is applied to analyze seven measured pulse signals at rest under different physiological conditions using a tactile sensor and a PPG sensor. Some observed differences between these conditions are validated with the related findings in the literature. As compared to instant frequency, the instant initial phase of a harmonic extracts respiration parameters with better accuracy. Since HR variability (HRV) affects arterial pulse waveform (APW), the extracted APW with a constant HR serves better for deriving arterial indices. Full article

Background/Objectives: Spatio-temporal gait parameters have been proposed as surrogate markers for objective, remote monitoring of global motor status in Parkinson’s disease (PD). Our observational, cross-sectional pilot study tested whether gait metrics, derived from wearable sensors, reflect dopaminergic responsiveness in both axial and appendicular functions. Methods: Twenty-two PD patients were evaluated both under and not under L-Dopa (ON and OFF states, respectively). Motor performance was assessed using wearable inertial sensors during standardized tasks involving gait and upper/lower limb movements. From the recorded kinematics, measures of movement amplitude, speed, rhythm, and consistency were extracted, and dopaminergic response was compared in appendicular and axial functions. Results: Treatment effects were more pronounced on the more affected body side. Improvements in appendicular amplitude, speed, and consistency closely matched those observed in spatio-temporal gait parameters. In contrast, rhythm measures displayed a divergent pattern, with reduced gait cadence but increased hand movement frequency, showing an inverse correlation. No significant correlations emerged between axial and appendicular domains for amplitude, velocity, or consistency, whereas improvements in step length and gait velocity were associated with MDS-UPDRS III motor scores. Conclusions: These findings overall suggest that specific gait metrics, particularly those reflecting amplitude and velocity, may provide reliable, sensor-based indicators of overall motor status in PD, supporting their use in remote monitoring. Full article

The development of NVH (Noise, Vibration, and Harshness) characteristics in vehicles is facing new challenges with the widespread utilization of electric drivetrains. This shift introduces new requirements in several areas, such as reduced noise and vibration levels, the need for advanced nonlinear characterization methods, and tuning/masking the typically more prominent tonal noise components. More accurate simulation and measurement techniques are essential to meet these demands. This study focuses on the experimental frequency response function (FRF) testing of electric drivetrain components, specifically on potential phase errors caused by inappropriate measurement settings. The influencing parameters and their quantitative effects are analyzed theoretically and demonstrated using real measurement data. A novel numerical approach, termed Maximum Phase Error Analysis (MPEA), is introduced to systematically quantify the largest potential phase errors due to arbitrary alignment between resonance frequencies and discrete spectral lines. MPEA enhances the robustness of phase accuracy assessment, especially critical for lightly damped systems and closely spaced resonance peaks. Based on the findings, optimal testing parameters are proposed to ensure phase errors remain within a predefined limit. The results can be applied in various dynamic testing scenarios, including durability testing and rattling analysis. Full article

With the increasing use of horizontal wells in oil and gas development, measurement-while-drilling (MWD) systems require higher magnetic azimuth accuracy to ensure precise trajectory control. This study proposes a three-stage magnetic azimuth error compensation method based on multi-station analysis (MSA). First, the OPTICS clustering algorithm is utilized to identify and remove noise points, and ellipse fitting is applied to suppress radial magnetic interference. Second, an improved MSA model incorporating wellbore trajectory constraints is developed to minimize axial interference and enhance correction stability. Finally, a Gaussian Process Regression (GPR) model, using accelerometer and magnetometer data as features, is introduced to model and compensate for residual nonlinear errors. Experimental validation under simulated complex magnetic conditions shows that OPTICS-based preprocessing significantly improves ellipse fitting and reduces hard magnetic interference. The improved MSA lowers the mean azimuth error to approximately 2.5°, while integrating GPR further decreases it to below 0.04°. The proposed GPR model achieves an R² of 0.99972 and an RMSE of 0.02928° on the test set, confirming its strong nonlinear compensation capability. Overall, the proposed framework effectively suppresses magnetic interference and enhances azimuth accuracy, providing a robust solution for high-precision MWD applications in horizontal wells. Full article

Background: Clozapine is the only antipsychotic medication proven effective in patients with treatment-resistant schizophrenia (TRS). However, many patients have serum concentrations outside the recommended therapeutic window, and clozapine exhibits substantial interindividual variability. This study aimed to (1) examine clozapine dosage and blood concentrations in patients with TRS; (2) investigate the effects of sex and age on dosage and blood concentrations; (3) assess clinical response to clozapine treatment; and (4) develop a random forest (RF) model to predict therapeutic response using clinical and therapeutic drug monitoring (TDM) data. Methods: Dried blood spots were used to measure concentrations of clozapine, norclozapine, and clozapine N-oxide. Clinical symptoms were assessed using the Brief Psychiatric Rating Scale (BPRS). The RF algorithm was applied to analyze the relationships between biochemical and demographic factors and clinical response to clozapine. Results: A total of 754 blood samples from 167 patients were analyzed. Men received higher doses than women, and glucose levels were elevated in both sexes. The area under the curve (AUC) of the receiver operating characteristic (ROC) curve was 0.986 for the training set and 0.852 for the testing set. Accuracy, precision, recall, and F1-score (training/testing) were 0.938/0.786, 0.936/0.736, 0.934/0.780, and 0.935/0.757, respectively. The SHapley Additive exPlanations (SHAP) analysis indicated that baseline BPRS score, treatment duration, age, and clozapine concentration were important variables contributing to the output of the model. Conclusions: Our model achieved satisfactory predictive performance for clinical response and provides valuable insights into personalized prediction of clozapine efficacy. Full article

Objectives: Pilates is frequently recommended for patients with Chronic Nonspecific Low Back Pain (CNLBP) due to its potential to enhance posture, muscle strength, trunk flexibility, and stability. However, to date, there is no robust evidence supporting the effectiveness of Pilates in managing CNLBP. This study aimed to assess the effects of 8 × 8 Pilates Matwork core exercises on pain and functioning in middle-aged adult women with CNLBP, through a flexion relaxation phenomenon (FRP) analysis. Methods: We included middle adult women (n = 21) with diagnosis of CNLBP and a Numeric Rating Scale (NRS) > 4. The experimental group underwent a treatment of eight Pilates Matwork sessions, biweekly for 4 weeks, lasting about 40 min. The control group underwent standardized exercises used for managing CNLBP. Outcome measures included NRS, Oswestry Disability Index (ODI), Quebec Back Pain Disability Scale (QBPDS), and the FRP ratio via surface electromyography during trunk maximum flexion. We evaluated the participants at the baseline (T0), at the end of the 4-week treatment (T1), and at 4 weeks after the end of the treatment, at 8 weeks from the baseline (T2). Results: In this pilot RCT, 21 middle-aged adult women affected by CNLBP were randomly allocated with a ratio of 1:1 in the Pilates group, and in parallel in the control group. The experimental group showed a significant improvement in ODI and QBPDS scores compared to the control group, maintained at follow-up for ODI, along with an NRS reduction at T2. About FRP, Pilates has proven to be comparable to conventional treatment, showing no significant difference in FRR at T1 and T2. Only the experimental group exceeded the 9.5 cutoff at T2, as a protective predictive index for CNLBP. Conclusions: This pilot RCT provided preliminary evidence that Pilates might be an effective rehabilitation method, enhancing functioning and pain management in middle-aged adult women affected by CNLBP. The FRP study proves to be efficient in translating clinical assessments into rehabilitation assessment measures. Full article

In order to realize the wide frequency applicability of the electromagnetic current transformer in a ‘double high’ power system, the equivalent circuit model of the electromagnetic current transformer under wide frequency is established. The complex permeability method is used to obtain the excitation impedance value on the basis of the existing core parameters. Secondly, according to the equivalent circuit of the current transformer in the broadband domain, the error transfer function of the electromagnetic current transformer is derived. Through simulation calculation, the ratio difference and angle difference in the electromagnetic current transformer at 50 Hz–3000 Hz are obtained. The correctness of the theoretical analysis and simulation model is verified by comparing it with the existing model and measurement. The simulation and test results show that the electromagnetic current transformer has good linearity when the frequency is in the frequency range of 50 to 650 Hz. When the frequency exceeds this frequency, the ratio difference and angle difference in the current transformer will not reach the accuracy standard, which indicates that it is difficult to accurately measure the high frequency current. Aiming at the correlation of frequency characteristics, this paper proposes a method of optimizing parameters, which provides a certain reference for the error compensation and structural design of electromagnetic current transformers. Full article

Removing orthodontic brackets often presents clinical challenges, as it may cause patient discomfort, bracket fracture, or enamel damage resulting from strong adhesive bonds. Various techniques have been proposed to facilitate safer and more efficient debonding. Among them, laser-assisted methods have gained attention for their potential to minimize mechanical stress and improve patient comfort. The main objective of this study was to evaluate the effect of an erbium-doped yttrium–aluminum–garnet (Er:YAG) laser as an alternative to traditional mechanical methods for removing metal and ceramic orthodontic brackets. Materials and Methods: Thirty-six extracted premolars were prepared for bonding metal or ceramic brackets using a light-cure adhesive system. The control group consisted of six ceramic and six metal brackets removed with conventional orthodontic pliers. In the experimental groups, brackets were debonded using the Er:YAG laser (2940 nm, 0.6 mm spot size, 150 mJ; 15 Hz; (2.25 W) with an H14 handpiece. Irradiation time was recorded for each method, and teeth were rescanned to measure the surface area and volume of the crowns before and after bracket removal. Data were analyzed using one-way ANOVA and Tukey’s HSD test (p < 0.05). Scanning electron microscopy (SEM) was used for surface analysis. Results: A significant difference in debonding time (p = 0.001) was observed between the laser and traditional methods. The laser group took 52.5 s for metal and 56.25 s for ceramic brackets, compared to 1.05 s (metal) and 0.64 s (ceramic) in the traditional group. A significant difference in remaining cement volume was noted (p = 0.0002), but no differences were found between metal and ceramic brackets with laser removal. Conclusions: Er:YAG laser-assisted debonding is safe and minimally invasive but more time-consuming and costly than conventional methods, showing no improvement in clinical efficiency under current parameters. Full article

Background: This study deploys the Lean Six Sigma DMAIC framework to achieve systemic optimization of the school subscription process in Tunisia’s public transport service, a critical administrative operation affecting efficiency and customer satisfaction across the urban mobility network. Methods: Beyond conventional applications, the research integrates advanced analytical and process engineering tools, including capability indices, measurement system analysis (MSA), variance decomposition, and root-cause prioritization through Pareto–ANOVA integration, supported by a structured control plan aligned with ISO 9001:2015 and ISO 31000:2018 risk-management standards. Results: Quantitative diagnosis revealed severe process instability and nonconformities in information flow, workload balancing, and suboptimal resource allocation that constrained effective capacity utilization. Corrective interventions were modeled and validated through statistical control and real-time performance dashboards to institutionalize improvements and sustain process stability. The implemented actions led to a 37.5% reduction in cycle time, an 80% decrease in process errors, a 38.5% increase in customer satisfaction, and a 38.9% improvement in throughput. Conclusions: This study contributes theoretically by positioning Lean Six Sigma as a data-centric governance framework for stochastic capacity optimization and process redesign in public service systems, and practically by providing a replicable, evidence-based roadmap for operational excellence in governmental organizations within developing economies. Full article

Monitoring nitrogen dioxide (NO₂) in various scenarios is crucial due to its significant environmental impact as a hazardous gas which is emitted by several industrial sectors. This study reports the optimized synthesis of WO₃ flower-like structures using the microwave-assisted hydrothermal method under various experimental conditions, resulting in the optimized sample designated MF-WO₃-K2. Structural, morphological, and chemical characterizations revealed that WO₃ microflowers (MF-WO₃-K2) exhibit a hexagonal crystalline phase, a bandgap of 2.4 eV, and a high specific surface area of 61 m²/g. The gas-sensing performance of WO₃ microflowers was investigated by electrical measurements of six similarly fabricated MF-WO₃-K2 sensors. The MF-WO₃-K2 sensors demonstrated a remarkable sensor signal of 225 for 5 ppm NO₂ at 150 °C and response/recovery times of 14.5/2.4 min, coupled with outstanding selectivity against potential interfering gases such as CO, H₂, C₂H₂, and C₂H₄. Additionally, the sensors achieved a low detection limit of 65 ppb for NO₂ at 150 °C. The exceptional sensing properties of WO₃ microflowers are attributed to the abundance of active sites on the surface, large specific surface area, and the presence of pores in the material that facilitate the diffusion of NO₂ molecules into the structure. Overall, the WO₃ microflowers demonstrate a promising ability to be used as a sensitive layer in high-performance chemiresistive gas sensors due to their high sensor performance and good reproducibility for NO₂ detection. Full article

The precise reconstruction of target scattering centers (TSCs) using sensors plays a crucial role in feature extraction and identification of non-cooperative targets. Radar sensor networks (RSNs) are well suited for this task, as they are capable of illuminating targets from multiple aspect angles and rapidly capturing reflected signals. However, the complex geometry and diverse material composition of real-world targets result in significant variations in the radar cross-section (RCS) observed at different angles. Although these RCS responses are interrelated, they exhibit considerable angular diversity. Furthermore, achieving precise spatiotemporal registration and fully coherent processing is infeasible for RSNs composed of small mobile sensor platforms, such as drone swarms. Therefore, an intelligent algorithm is required to extract and accumulate correlated and meaningful information from the target echoes received by the RSN. In this work, a novel collaborative TSC reconstruction framework for RSNs is proposed. The framework performs similarity evaluation on wide-angle high-resolution range profiles (HRRPs) to achieve adaptive angular segmentation of TSC models. It combines the expectation–maximization (EM) algorithm with an enhanced Arctic puffin optimization (EAPO) algorithm to effectively integrate echo information from the RSN in a non-coherent manner, thereby enabling accurate TSC estimation. The proposed method outperforms existing mainstream approaches in terms of spatiotemporal registration requirements, estimation accuracy, and stability. Comparative experiments on measured datasets demonstrate the robustness of the framework and its adaptability to complex target scattering characteristics, confirming its practical value. Full article

Posterior instrumentation is used to treat severe adolescent idiopathic scoliosis (AIS) with a Cobb angle greater than 40 degrees. Clinical studies indicate that AIS patients may develop adjacent segment degeneration (ASD) post-surgery. However, there is limited research on the biomechanical effects on adjacent segments after surgery, and straightforward methods for creating finite element (FE) models that reflect vertebral deformation are lacking. Therefore, this study aims to use biplanar X-ray images to establish a case-specific, parameterized FE model reflecting coronal plane vertebral deformation and employ FE analysis to compare pre- and postoperative changes in the range of motion (ROM), endplate stress, and intervertebral disk stress of adjacent segments. We developed an FE model from biplanar X-ray images of a patient with AIS, using ANSYS software to establish pre- and postoperative models. The shape of the preoperative model was validated using computed tomography (CT) reconstruction. A flexion moment was applied to C7 of the spine model to achieve the same forward bending angle in the pre- and postoperative models. This study successfully developed a case-specific parameterized FE model based on X-ray images. The differences between Cobb angle and thoracolumbar kyphosis angle measurements in X-ray images and CT reconstructions were 6.5 and 5.4 mm. This FE model was used to analyze biomechanical effects on motion segments adjacent to the fixation site, revealing a decrease in maximum endplate and disk stress in the cranial segment and an increase in stress in the caudal segment. Full article

Background/Objectives: Metabolic dysfunction-associated steatotic liver disease (MASLD) is becoming more common among adolescents, but non-invasive biomarkers for early detection are still limited. Liver-expressed antimicrobial peptide-2 (LEAP-2), a ghrelin receptor antagonist, has been connected to obesity and liver fat buildup in adults, but pediatric data are limited. This study investigates the hypothesis that higher levels of LEAP-2 are associated with hepatic steatosis and the role of LEAP-2 serum levels in the earlier and easier diagnosis of MASLD in children. Methods: In this cross-sectional study, 51 adolescents aged 12–18 were divided into three groups: one with MASLD and obesity (MASLD-Ob) (confirmed hepatosteatosis by imaging studies such as magnetic resonance or ultrasound, along with at least one cardiometabolic criterion and a body mass index (BMI) > 2 SD) (n = 19), another with obesity without any liver pathology or MASLD (BMI > 2 SD) (n = 14), and healthy controls (n = 18). The controlled attenuation parameter (CAP) was measured using FibroScan^® Mini + 430 (Echosens SA, Créteil, France), and serum ghrelin and LEAP-2 levels were determined via ELISA. Correlations between LEAP-2, ghrelin, CAP, BMI z-score, and metabolic parameters were analyzed. Results: LEAP-2 and ghrelin levels among the three groups were similar (p = 0.148, p = 0.515). A positive correlation was observed between LEAP-2 levels and CAP values in the obese group (both the MASLD-Ob and obesity groups) (r = 0.379, p = 0.030). When a cutoff of 240 dB/m was used, the median LEAP-2 level in cases above this value was 2.20 ng/mL, compared to 1.37 ng/mL in cases below it (p = 0.021), which was significantly different. When analyzing the obese group (both the MASLD-Ob and obese groups) a statistically significant correlation was found between serum LEAP-2 levels and CAP, AST, GGT, and total bilirubin values (r = 0.379, p = 0.030; r = 0.369, p = 0.035; r = 0.369, p = 0.035; r = 0.357, p = 0.049, respectively). Conclusions: Interventional imaging methods and biomarkers for diagnosing and monitoring hepatosteatosis have become well-established in the literature. However, since these tests are not available at all centers and can be costly, there is an increasing search for other easily accessible diagnostic and follow-up parameters. LEAP-2 could be a promising non-invasive biomarker for pediatric MASLD, especially when used alongside CAP measurements. The application of this biomarker in pediatric MASLD provides valuable data to help identify and monitor the condition in adolescents. We believe our study offers strong evidence to support further research and the development of drug treatments for MASLD that aim to reduce plasma LEAP-2. Full article