Search Results (329)

Magnesium alloys, like AZ31, possess a desirable low weight and high specific strength, which make them favorable for aerospace and auto applications, yet their difficulty to machine limits their broader implementation for the industry. Electrical discharge machining (EDM) is an effective technology for machining difficult-to-machine materials, particularly when the materials are reinforced with ceramic and graphene-based fillers. This study examines the impact of reinforcement percentage (R) and different electrical discharge machining (EDM) parameters such as current (I), pulse on time (T_on) and pulse off time (T_off) on the material removal rate (MRR) and surface roughness (SR) of AZ31/B₄C/GNPs composites. The combined reinforcement range varies from 2 wt.% to 4 wt.%. The Taguchi design (L27) is utilized to conduct the experiments in this study. ANOVA of the experimental data indicated that current (I) significantly affects MRR and SR, exhibiting the greatest contribution of 44.93% and 51.39% on MRR and SR, respectively, among the variables analyzed. The surface integrity properties of EDMed surfaces are examined using SEM under both higher and lower material removal rate settings. Diverse machine learning techniques, including linear regression (LR), polynomial regression (PR), Random Forest (RF), and Gradient Boost Regression (GBR), are employed to construct an efficient predictive model for outcome estimation. The built models are trained and evaluated using 80% and 20% of the total data points, respectively. Statistical measures (MSE, RMSE, and R²) are utilized to evaluate the performance of the models. Among all the developed models, GBR exhibited superior performance in predicting MRR and SR, achieving high accuracy (exceeding 92%) and lower error rates compared to the other models evaluated in this work. This work demonstrated the synergy between techniques in optimizing EDM performance for hybrid composites using a statistical design and machine learning strategies that will facilitate greater use of hybrid composites in high-precision engineering applications and advanced manufacturing sectors. Full article

Introduction: Intermittent theta burst stimulation (iTBS) has been associated with improvements in the negative symptoms (NSs) of schizophrenia. However, optimizing by shorter protocols remains necessary. Furthermore, understanding their impact on other clinical symptoms, sleep, and autonomic regulation is important to underlying therapeutic effects. Objectives: Evaluate the efficacy of an accelerated iTBS protocol on reducing NSs in patients with schizophrenia. We hypothesize a 20% reduction in BNSS scores in the active group, as well as improvements in disorder-related aspects, including sleep patterns, symptoms severity, and cognition. Methods: A double-blind, randomized, sham-controlled clinical trial design will be conducted to test the effects of the accelerated iTBS protocol in 60 participants with schizophrenia (30 active and 30 sham) with moderate NSs. iTBS protocol will consist of four daily sessions, with 600 pulses per session for five consecutive days. Patients will be assessed at three time points (baseline, after intervention and 30 days follow up) for clinical symptoms, cognition and heart rate variability. The primary outcome will be negative symptoms using the Brief Negative Symptom Scale (BNSS). Study register: Brazilian Registry of Clinical Trials (CAEE: 71102823.4.0000.5505). Conclusions: The accelerated iTBS protocol has demonstrated promising effects on NSs. However, it is still necessary to establish an effective and feasible high-dosage protocol. This study will contribute to optimizing therapeutic protocols for schizophrenia, with a particular focus on clinical applicability. Additionally, it will provide an opportunity to deepen the understanding of the physiological effects of neuromodulation, contributing to the understanding of its underlying mechanisms. Full article

Background: In exercise testing, the ventilatory threshold 1 (VT1) and ventilatory threshold 2 (VT2) are used in lifestyle-related diseases, cardiac rehabilitation, and athletic training. We investigated a VT2 measuring method using a pulse oximeter. Methods: Thirty-four adults (men: 15; women: 19) performed a bicycle ergometer Ramp Test. VT1 values were determined using expiratory gas data. The bifurcation of the curve obtained by designating the pulse rate (PR) as an independent variable and SpO₂/PR as a dependent variable was calculated using the residual sum of squares and defined as the SpO₂ threshold (ST) (SpO₂-Slope method). A second bifurcation with ST as the origin was further defined (ST2). ST2 validity was assessed by comparing and analyzing the differences and correlations with each VT2 obtained by expiratory gas analysis. Results: The correlation between ST2 determined by the SpO₂-Slope method using PR as an index and VT2 obtained from respiratory gas analysis was significant, showing a positive correlation (r = 0.74~0.92; p < 0.01), with most data points falling within the 1.96 ± SD in the Bland–Altman analysis. Conclusions: ST2 values derived from SpO₂ and pulse rate measurements by pulse oximeter may be a valuable VT2 measuring method. Full article

Climate change intensifies the challenges surrounding water cycling and vegetation dynamics in arid desert ecosystems, calling for detailed observations to decode adaptive plant strategies and support restoration efforts. This study analyzes interannual variations in water budgets and vegetation coverage in two distinct desert systems—K. foliatum (midstream) and R. songarica (downstream)—within the Heihe River Basin from 2016 to 2021. We uncover a pronounced ecohydrological contrast: the K. foliatum ecosystem displays substantial soil moisture variability alongside high precipitation and evapotranspiration rates, leading to a soil water deficit. In contrast, the R. songarica ecosystem maintains minimal moisture fluctuation under extreme aridity, yet records a slight water surplus. Notably, vegetation coverage in K. foliatum closely correlates with soil water storage, precipitation, and evapotranspiration, whereas R. songarica exhibits no significant hydrological coupling, implying a pulsed response to episodic rainfall. Groundwater recharge emerges as a key compensatory mechanism against rainfall shortages in midstream regions. These findings underscore the need for region-specific management—prioritizing groundwater conservation downstream and intelligent irrigation regulation midstream—offering a science-backed pathway for restoring and managing water resources in arid inland basins under climate change. Full article

Background: Autonomic nervous system (ANS) and vascular factors are associated with glaucoma. However, the association between systemic comorbidity burden and ANS and hemodynamic function in patients with glaucoma remains unclear. This study aimed to examine the association between heart rate variability (HRV) and acceleration plethysmography (APG) parameters and the age-adjusted Charlson Comorbidity Index (ACCI) in patients with glaucoma. Methods: A total of 260 subjects (260 eyes), including 186 with primary open-angle glaucoma (PG) and 74 with exfoliation glaucoma (EG), were enrolled at Shimane University Hospital from June 2023 to July 2024. HRV and APG were assessed using a sphygmograph (TAS9 Pulse Analyzer Plus View). HRV parameters included time-domain measures (SDNN, RMSSD, CVRR) and frequency-domain measures (TP, VLF, LF, HF, LF/HF). APG parameters included the a, b, c, d, and e components of the accelerated pulse wave, and the following vascular types: Type A, Type B, and Type C. The association between ACCI and HRV and APG parameters was evaluated using Spearman’s rank correlation and multivariate regression adjusted for sex, body mass index, pulse rate, systolic and diastolic blood pressure, intraocular pressure, medication score, mean deviation, and glaucoma type. Results: By univariate analysis, against ACCI, significant inverse correlations were observed for several parameters: LnLF (R = −0.17, p = 0.0062); LnLF/LnHF (R = −0.24, p = 0.00012); b peak (R = −0.14, p = 0.031); d peak (R = −0.17, p = 0.0072); and e peak (R = −0.15, p = 0.015). Regarding HRV parameters, multivariate linear regression models showed that ACCI was significantly positively associated with RMSSD (coefficient: 2.861; 95% CI: 0.447 to 5.274) and significantly negatively associated with the frequency-domain parameters LnLF (coefficient: −0.127; 95% CI: −0.245 to −0.009) and LnLF/LnHF (coefficient: −0.038; 95% CI: −0.062 to −0.014). In APG parameters, the c peak was significant associated with ACCI (coefficient: −12.6; 95% CI: −22.5 to −2.69). ACCI was significantly associated with Type B (coefficient: 0.305; 95% CI: 0.057 to 0.552). Conclusions: Greater systemic comorbidity burden may be related to impaired ANS regulation and increased vascular stiffness in glaucoma patients. Full article

Pulse width modulation (PWM) allows for the real-time flow rate adjustment of spray nozzles without changing system pressure, indicating that PWM is a promising technology for improving the quality of pesticide applications. However, its effect on the droplet formation process is not yet fully understood. In this study, the effects of a PWM system on the droplet spectrum and velocity generated by different flat fan hydraulic nozzles were evaluated. The experiment was conducted via a spray simulator to test the impact of PWM technology under various operational conditions and flat fan nozzle types (standard, pre-orifice, and air inclusion). With the aid of a real-time particle analyzer and high-resolution imaging, the following variables were analyzed: volume median diameter (VMD), relative span, droplet velocity, and the percentage of volume composed of droplets with a diameter smaller than 100 µm. Four simulated working speeds (1.1, 1.7, 2.8, and 3.9 m s⁻¹), which were equivalent to four PWM valve duty cycles (35%, 42%, 71%, and 100%), respectively, were evaluated. The PWM system altered the droplet size, generally reducing the VMD in comparison to the conventional system. The relative span was not influenced by the PWM system’s duty cycle, although system activation increased droplet size heterogeneity in some nozzle types. The droplet velocity was generally slower using the PWM system in comparison with the conventional system, but higher duty cycles increased this parameter. Overall, the results of this study suggest that spray patterns are altered by PWM activation, and the traits of this behaviour depend on the spray nozzle type. Full article

Background: Chronic musculoskeletal pain (CMP) is a multidimensional condition involving both peripheral and central mechanisms, with increasing evidence supporting an interplay between subjective pain perception and autonomic nervous system (ANS) function. However, few studies have explored whether a single non-invasive intervention can concurrently modulate both domains. Objectives: To evaluate the short-term effects of a single session of Pulsed Electromagnetic Field (PEMF) therapy—administered via the PAP Ion Magnetic Induction (PAPIMI™) device—on subjective pain intensity and heart rate variability (HRV) parameters in individuals with CMP. The relationship between perceived pain relief and physiological autonomic adaptations was also explored. Methods: Thirty adults with CMP underwent a single PAPIMI™ session. Subjective pain intensity was measured using the Numeric Pain Rating Scale (NPRS), while autonomic function was assessed via HRV. Pre- to post-intervention changes were analyzed using the Wilcoxon Signed-Rank test, while Spearman’s correlation was computed to assess associations between post-intervention changes in subjective perceived pain and HRV parameters. Results: A significant reduction in NPRS scores (p < 0.001) was found after PAPIMI intervention. Also, a significant increase in specific parasympathetic-related HRV indices, namely, RMSSD (p = 0.015) and HF power (p = 0.029), was observed. No significant correlations were found between post-intervention changes in pain perception and HRV metrics. Conclusions: A single PAPIMI session induced both analgesic effects and improvements in autonomic balance in individuals with CMP. These findings underscore the potential of PAPIMI as a non-pharmacological approach for rapid pain modulation and systemic rebalancing. Full article

Background/Objectives: Increased blood pressure variability (BPV) was found in adults with primary (essential) hypertension (PH) and is associated with increased cardiovascular risk. Our study aimed to analyze the relation between BPV and low-grade inflammation in children with primary hypertension. Methods: In 56 treatment-naive pediatric patients with PH (15.1 ± 2.1 years) and 30 healthy children (14.9 ± 1.4 years), we evaluated BPV: BP dipping, standard deviation (SD) of ambulatory blood pressure measurements (ABPMs), pulse pressure (PP)/systolic blood pressure ratio (24 h PP/SBP), rate–pressure index (24 h RPI), 24-h weighted BPV (24 h WSBPV, 24 h WDBV, 24 h WMAPV), coefficient of variation (24 h CoVSBP, 24 h CoVDBP, 24 h CoVMAP), ambulatory arterial stiffness index (AASI), and morning BP surge. We also analyzed indices of subclinical inflammation (markers derived from complete blood count, high-sensitivity C-reactive protein (CRP), interleukin 18), and office and ambulatory BP. Results: Patients with PH had significantly higher hsCRP, neutrophils, monocytes, and platelets, neutrophil-to-lymphocyte (NLR), platelet-to-mean platelet volume (PMPVR), and lower monocyte-to-neutrophil (MNR) ratios, and higher BPV: 24 h ABPM SBP SD, 24 h ABPM MAP SD, 24 h RPI, 24 h WSBPV, 24 h WDBV, 24 h WMAPV, and 24 h CoVSBP. Low-grade inflammation markers correlated with BPV indices in both groups. In multivariate analysis, MNR predicted 24 h ABPM MAP SD (beta = 0.290, 95CI: 0.029–0.551), 24 h RPI (beta = −0.348, 95CI: −0.587–−0.108), and 24 h WDBPV (beta = 0.286, 95CI: 0.032–0.540); monocyte count—24 h RPI (beta = 0.281, 95CI: 0.041–0.521), and hsCRP—24 h WDBV (beta = 0.310, 95CI: 0.055–0.564). ROC analysis revealed a good diagnostic profile for lymphocyte count as a positive determinant of non-dipping status in PH children (cut-off point 2.59 [×10³/µL]). Conclusions: BPV is higher in children with PH compared to healthy peers and is associated with low-grade inflammation. MNR may be the most helpful indicator of BPV, whereas high lymphocyte count predicts the best non-dipping status in these patients. Full article

The Red River Jig is a traditional Métis dance practiced among Indigenous and non-Indigenous Peoples. While exercise improves physical health and fitness, the impacts of cultural dances on wholistic health are less clear. This study aimed to investigate the psychosocial (cultural and mental), social, physical function, and physical fitness benefits of a Red River Jig intervention. In partnership with Li Toneur Nimiyitoohk Métis Dance Group, Indigenous and non-Indigenous adults (N = 40, 39 ± 15 years, 32 females) completed an 8-week Red River Jig intervention. Social support, cultural identity, memory, and mental wellbeing questionnaires, seated blood pressure and heart rate, weight, pulse-wave velocity, heart rate variability, baroreceptor sensitivity, jump height, sit-and-reach flexibility, one-leg and tandem balance, and six-minute walk test were assessed pre- and post-intervention. Community, family, and friend support scores, six-minute walk distance (553.0 ± 88.7 m vs. 602.2 ± 138.6 m, p = 0.002), jump, leg power, and systolic blood pressure low-to-high-frequency ratio increased after the intervention. Ethnic identity remained the same while affirmation and belonging declined, leading to declines in overall cultural identity, as learning about Métis culture through the Red River Jig may highlight gaps in cultural knowledge. Seated systolic blood pressure (116.5 ± 7.3 mmHg vs. 112.5 ± 10.7 mmHg, p = 0.01) and lower peripheral pulse-wave velocity (10.0 ± 2.0 m·s⁻¹ vs. 9.4 ± 1.9 m·s⁻¹, p = 0.04) decreased after the intervention. Red River Jig dance training can improve social support, physical function, and physical fitness for Indigenous and non-Indigenous adults. Full article

Virtual fencing (VF) offers a promising alternative to conventional or electrified fences for managing livestock grazing distribution. This study evaluated the behavioral responses of 25 Rarámuri Criollo cows fitted with Nofence^® collars in Pine Valley, CA, USA. The VF system was deployed in chaparral rangeland pastures. The study included a 14-day training phase followed by an 18-day testing phase. The collar-recorded variables, including audio warnings and electric pulses, animal movement, and daily typical behavior patterns of cows classified into a High or Low virtual fence response group, were compared using repeated-measure analyses with mixed models. During training, High-response cows (i.e., resistant responders) received more audio warnings and electric pulses, while Low-response cows (i.e., active responders) had fewer audio warnings and electric pulses, explored smaller areas, and exhibited lower mobility. Despite these differences, both groups showed a time-dependent decrease in the pulse-to-warning ratio, indicating increased reliance on audio cues and reduced need for electrical stimulation to achieve similar containment rates. In the testing phase, both groups maintained high containment with minimal reinforcement. The study found that Rarámuri Criollo cows can effectively adapt to virtual fencing technology, achieving over 99% containment rate while displaying typical diurnal patterns for grazing, resting, or traveling behavior. These findings support the technical feasibility of using virtual fencing in chaparral rangelands and underscore the importance of accounting for individual behavioral variability in behavior-based containment systems. Full article

Background/Objectives: Heart rate variability (HRV) is a marker of autonomic nervous system function, based on fluctuations in heartbeat intervals. Although several studies have investigated the association between frequency-domain HRV parameters and glaucoma, evidence based on large sample sizes remains limited. Therefore, the present study aimed to examine the relationship between frequency-domain HRV parameters and glaucoma subtypes, including primary open-angle glaucoma (PG) and exfoliation glaucoma (EG), using a larger sample size. Methods: Participants with primary open-angle glaucoma (PG), exfoliation glaucoma (EG), or no ocular disease other than cataract (controls) were recruited at Shimane University between June 2023 and July 2024. Frequency-domain HRV parameters (total power [TP], very-low-frequency [VLF], low-frequency [LF], high-frequency [HF], and LF/HF) were measured using a sphygmograph (TAS9 Pulse Analyzer Plus View). Group comparisons were conducted using unpaired t-tests, Fisher’s exact tests, and Tukey’s HSD test. Multivariate analyses were performed to identify factors associated with each HRV parameter. Results: A total of 809 participants were analyzed, including 522 with PG, 191 with EG, and 96 controls. The EG group showed significantly lower values across all frequency-domain HRV parameters compared to the PG group, and significantly lower LnLF values than the control group (p = 0.012). Multivariate analyses revealed that no significant associations were found between HRV measures and the presence of glaucoma or pseudoexfoliation material (PEM) deposition. Older age was significantly associated with lower values across all HRV parameters. Conclusions: In elderly glaucoma patients, age-related alterations in frequency-domain HRV parameters have been observed. Full article

Quantum memory is essential for the prolonged storage and retrieval of quantum information. Nevertheless, no current studies have focused on the creation of effective quantum memory for continuous variables while accounting for the decoherence rate. This work presents an effective continuous-variable quantum key distribution method with parameter optimization utilizing the Elitist Elk Herd Random Immigrants Optimizer (2E-HRIO) technique. At the outset of transmission, the quantum device undergoes initialization and authentication via Compressed Hash-based Message Authentication Code with Encoded Post-Quantum Hash (CHMAC-EPQH). The settings are subsequently optimized from the authenticated device via 2E-HRIO, which mitigates the effects of decoherence by adaptively tuning system parameters. Subsequently, quantum bits are produced from the verified device, and pilot insertion is executed within the quantum bits. The pilot-inserted signal is thereafter subjected to pulse shaping using a Gaussian filter. The pulse-shaped signal undergoes modulation. Authenticated post-modulation, the prediction of link failure is conducted through an authenticated channel using Radial Density-Based Spatial Clustering of Applications with Noise. Subsequently, transmission occurs via a non-failure connection. The receiver performs channel equalization on the received signal with Recursive Regularized Least Mean Squares. Subsequently, a dataset for side-channel attack authentication is gathered and preprocessed, followed by feature extraction and classification using Adaptive Depthwise Separable Convolutional Neural Networks (ADS-CNNs), which enhances security against side-channel attacks. The quantum state is evaluated based on the signal received, and raw data are collected. Thereafter, a connection is established between the transmitter and receiver. Both the transmitter and receiver perform the scanning process. Thereafter, the calculation and correction of the error rate are performed based on the sifting results. Ultimately, privacy amplification and key authentication are performed using the repaired key via B-CHMAC-EPQH. The proposed system demonstrated improved resistance to decoherence and side-channel attacks, while achieving a reconciliation efficiency above 90% and increased key generation rate. Full article

Background: Ambulatory blood pressure monitoring (ABPM) is increasingly recognized as a more reliable indicator of blood pressure status in children than clinic-based measurements, with superior predictive value for cardiovascular morbidity and mortality. However, evidence on the clinical utility of ABPM-derived indices, such as pulse pressure (PP), pulse pressure index (PPI), rate pressure product (RPP), ambulatory arterial stiffness index (AASI), and average real variability (ARV), remains underexplored in the pediatric population, particularly among children with chronic kidney disease (CKD). Objective: To evaluate the correlation between ABPM-derived indices in children, with a subgroup analysis comparing those with and without CKD. Secondary objectives included identifying factors associated with AASI and ARV and assessing their utility in cardiovascular risk stratification. Methods: In this bicentric cross-sectional study, 70 children (41 with CKD and 29 controls) were enrolled. ABPM indices (PP, PPI, RPP, AASI, and ARV) were calculated, and both descriptive and inferential statistical analyses, including linear regression, were performed. Results: Systolic and diastolic hypertension were significant predictors of elevated ARV (p < 0.05), while body mass index (BMI) and glomerular filtration rate (GFR) were positively associated with AASI (p < 0.05). Use of angiotensin-converting enzyme inhibitors (ACEIs) was associated with reduced arterial stiffness (p = 0.02). Significant differences were observed in weight, BMI, PP, and PPI between the CKD and non-CKD groups, with ABPM demonstrating greater sensitivity in detecting vascular health markers. Conclusions: ABPM-derived indices, particularly PP, PPI, and ARV, show promise in improving cardiovascular risk assessment in children. These findings support the broader use of ABPM metrics for refined cardiovascular evaluation, especially in pediatric CKD. Full article

Introduction: Rapid ascent to altitudes of over 5000 m above sea level are associated with dramatic changes in adaptive physiology. The effects of a gradual ascent on symptoms, oximetry, and heart rate are described and compared with the effects of a rapid ascent to the same altitude by a comparable cohort. Methods: A group of 13 individuals (six females) representing 10 countries from five continents ascended gradually from Lukla (2300 m) to Everest Base Camp (5300 m) in Nepal over an 8-day period, then descended over a further 4 days. All symptoms and medication were recorded, along with pulse oximetry (SpO₂) and heart rate (HR) every 500 m of ascent. The results were then compared with those obtained at equivalent altitudes using similar methodology from a fast ascent of Mount Kilimanjaro to an equivalent altitude by a comparable cohort over 4 days. Results: The gradual ascent group had a median age of 33 years (range 25–66), and all successfully completed the trek. No severe headache, vomiting, orthopnoea, or productive cough occurred, although minor nausea and mild headache were common. Baseline oximetry fell from a median of 96% (93–97%) to a median of 78% (53–86%) at 8 days but recovered to 94% (89–99%) inside 4 days. Corresponding HR rose from a baseline median of 72 bpm (57–85) to a median of 103 bpm (78–115) at 8 days, then recovered to 80 bpm (54–94) after 4 days. Neither age nor gender correlated with outcomes. Individually, HR correlated inversely with oximetry, but there was no group correlation between these two variables. By contrast, a more rapid 4-day ascent from the same starting height, with similar baseline values for HR and oximetry, to the same final altitude was associated with more severe headache, breathlessness, and vomiting. Fast ascent was associated with a significantly more marked reduction in oximetry to a median of 71% (52–76) and an increase in HR to a median of 110 bpm (88–140). The fast ascent group also required significantly more medication, rated their experience as less enjoyable, and had a 100% incidence of acute mountain sickness compared to 0% in the slow ascent group. Discussion: Oxygen desaturation and tachycardia are inevitable consequences of ascending above 5000 m, but the degree to which this occurs can be reduced by slowing ascent times and taking rest days every 1000 m of ascent. This practice is associated with fewer symptoms and greater safety, with less need for either prophylactic or therapeutic medication. Careful consideration should be given to rates of ascent when climbing to altitudes at or above 5000 m. Full article

Electrospinning has evolved into a vital nanofiber production technique with broad applications across biomedical, environmental, and industrial sectors. Alternating current (AC) and pulsed voltage (PV) electrospinning offer transformative alternatives by utilizing time-varying electric fields to overcome the drawbacks of DC electrospinning by employing an oscillating electric field that facilitates balanced charge dynamics, improved jet stability, and collectorless operation, leading to enhanced fiber alignment and significantly higher production rates, with reports exceeding 20 g/h. Conversely, PV electrospinning applies intermittent high-voltage pulses, offering precise control over jet initiation and termination. This method enables the fabrication of ultrafine, bead-free, and structurally uniform fibers, making it particularly suitable for biomedical applications such as controlled drug delivery and tissue scaffolds. Both techniques support tunable fiber morphology, reduced diameter variability, and improved structural uniformity, contributing to the advancement of high-performance nanofiber materials. This review examines the underlying electrohydrodynamic mechanisms, charge transport behavior, equipment configurations, and performance metrics associated with AC and PV electrospinning. It further highlights key innovations, current limitations in scalability and standardization, and prospective research directions. Full article