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Journal of Clinical Sleep Medicine :... Apr 2024This study investigated the impact of APAP therapy on vascular behavior and its potential to lower cardiovascular risk in patients with OSA, as well as differentiating...
Evaluating the impact of automatic positive airway pressure therapy on cardiovascular risk index and vascular behavior in patients with obstructive sleep apnea: a study on heterogeneity in the therapeutic response.
STUDY OBJECTIVES
This study investigated the impact of APAP therapy on vascular behavior and its potential to lower cardiovascular risk in patients with OSA, as well as differentiating APAP therapy heterogeneity.
METHODS
All participants were diagnosed with OSA by portable monitoring, and pulse wave parameters and cardiac risk composite parameter index (CRI) were obtained by photoplethysmography before and after APAP. Clustering analysis of pulse wave parameters before APAP in the high-risk population was performed using k-means clustering. Linear regression was used to assess the associations of changes in CRI and pulse wave parameters with clinical characteristics.
RESULTS
Eighty-two patients with OSA underwent APAP therapy. The CRI after APAP was significantly lower than before APAP (0.38± 0.33 and 0.58 ± 0.31, respectively; p < 0.001). All pulse wave parameters (except irregular pulse) were significantly different (p < 0.001) in patients with OSA and in the high-risk responders group after versus before APAP. The differences in pulse wave parameters after versus before APAP were not significant in the high-risk non-responders group, except for RCRD and pulse rate variability. Four clusters were obtained from the clustering analysis of pulse wave parameters before APAP in the high-risk responders group.
CONCLUSIONS
APAP reduces the CRI in patients with OSA by altering vascular behavior. Overnight photoplethysmography monitoring of pulse wave parameters can be used to assess whether patients with OSA will benefit from APAP.
PubMed: 38648118
DOI: 10.5664/jcsm.11162 -
Scientific Reports Apr 2024Arrhythmias are irregular heartbeat rhythms caused by various conditions. Automated ECG signal classification aids in diagnosing and predicting arrhythmias. Current...
Arrhythmias are irregular heartbeat rhythms caused by various conditions. Automated ECG signal classification aids in diagnosing and predicting arrhythmias. Current studies mostly focus on 1D ECG signals, overlooking the fusion of multiple ECG modalities for enhanced analysis. We converted ECG signals into modal images using RP, GAF, and MTF, inputting them into our classification model. To optimize detail retention, we introduced a CNN-based model with FCA for multimodal ECG tasks. Achieving 99.6% accuracy on the MIT-BIH arrhythmia database for five arrhythmias, our method outperforms prior models. Experimental results confirm its reliability for ECG classification tasks.
Topics: Humans; Algorithms; Heart Rate; Reproducibility of Results; Electrocardiography; Signal Processing, Computer-Assisted; Neural Networks, Computer; Arrhythmias, Cardiac
PubMed: 38627498
DOI: 10.1038/s41598-024-59311-0 -
Nanomaterials (Basel, Switzerland) Mar 2024Multi-exciton generation by multi-photon absorption under low-energy photons can be thought a reasonable method to reduce the risk of optical damage, especially in...
Multi-exciton generation by multi-photon absorption under low-energy photons can be thought a reasonable method to reduce the risk of optical damage, especially in photoelectric quantum dot (QD) devices. The lifetime of the multi-exciton state plays a key role in the utilization of photon-induced carriers, which depends on the dynamics of the exciton generation process in materials. In this paper, the exciton generation dynamics of the photon absorption under low-frequency light in CdSe QDs are successfully detected and studied by the temporal resolution transient absorption (TA) spectroscopy method. Since the cooling time of hot excitons extends while the rate of auger recombination is accelerated when incident energy is increased, the filling time of defect states is irregular, and exciton generation experiences a transition from single-photon absorption to multi-photon absorption. This result shows how to change the excitation. Optical parameters can prolong the lifetime of excitons, thus fully extracting excitons and improving the photoelectric conversion efficiency of QD optoelectronic devices, which provides theoretical and experimental support for the development of QD optoelectronic devices.
PubMed: 38607093
DOI: 10.3390/nano14070558 -
Journal of Clinical Medicine Feb 2024Atrial fibrillation (AF), the most common cardiac arrhythmia, is associated with adverse CV outcomes. Vascular aging (VA), which is defined as the progressive... (Review)
Review
Atrial fibrillation (AF), the most common cardiac arrhythmia, is associated with adverse CV outcomes. Vascular aging (VA), which is defined as the progressive deterioration of arterial function and structure over a lifetime, is an independent predictor of both AF development and CV events. A timing identification and treatment of early VA has therefore the potential to reduce the risk of AF incidence and related CV events. A network of scientists and clinicians from the COST Action VascAgeNet identified five clinically and methodologically relevant questions regarding the relationship between AF and VA and conducted a narrative review of the literature to find potential answers. These are: (1) Are VA biomarkers associated with AF? (2) Does early VA predict AF occurrence better than chronological aging? (3) Is early VA a risk enhancer for the occurrence of CV events in AF patients? (4) Are devices measuring VA suitable to perform subclinical AF detection? (5) Does atrial-fibrillation-related rhythm irregularity have a negative impact on the measurement of vascular age? Results showed that VA is a powerful and independent predictor of AF incidence, however, its role as risk modifier for the occurrence of CV events in patients with AF is debatable. Limited and inconclusive data exist regarding the reliability of VA measurement in the presence of rhythm irregularities associated with AF. To date, no device is equipped with tools capable of detecting AF during VA measurements. This represents a missed opportunity to effectively perform CV prevention in people at high risk. Further advances are needed to fill knowledge gaps in this field.
PubMed: 38592046
DOI: 10.3390/jcm13051207 -
ArXiv Mar 2024Deep Brain Stimulation (DBS) stands as an effective intervention for alleviating the motor symptoms of Parkinson's disease (PD). Traditional commercial DBS devices are...
Deep Brain Stimulation (DBS) stands as an effective intervention for alleviating the motor symptoms of Parkinson's disease (PD). Traditional commercial DBS devices are only able to deliver fixed-frequency periodic pulses to the basal ganglia (BG) regions of the brain, i.e., continuous DBS (cDBS). However, they in general suffer from energy inefficiency and side effects, such as speech impairment. Recent research has focused on adaptive DBS (aDBS) to resolve the limitations of cDBS. Specifically, reinforcement learning (RL) based approaches have been developed to adapt the frequencies of the stimuli in order to achieve both energy efficiency and treatment efficacy. However, RL approaches in general require significant amount of training data and computational resources, making it intractable to integrate RL policies into real-time embedded systems as needed in aDBS. In contrast, contextual multi-armed bandits (CMAB) in general lead to better sample efficiency compared to RL. In this study, we propose a CMAB solution for aDBS. Specifically, we define the context as the signals capturing irregular neuronal firing activities in the BG regions (i.e., beta-band power spectral density), while each arm signifies the (discretized) pulse frequency of the stimulation. Moreover, an {\epsilon}-exploring strategy is introduced on top of the classic Thompson sampling method, leading to an algorithm called {\epsilon}-Neural Thompson sampling ({\epsilon}-NeuralTS), such that the learned CMAB policy can better balance exploration and exploitation of the BG environment. The {\epsilon}-NeuralTS algorithm is evaluated using a computation BG model that captures the neuronal activities in PD patients' brains. The results show that our method outperforms both existing cDBS methods and CMAB baselines.
PubMed: 38560737
DOI: No ID Found -
Sensors (Basel, Switzerland) Mar 2024Dimetridazole (DMZ), a nitroimidazole derivative, is a notable antibiotic that has garnered growing interest in the medical community owing to its noteworthy...
Dimetridazole (DMZ), a nitroimidazole derivative, is a notable antibiotic that has garnered growing interest in the medical community owing to its noteworthy pharmacological and toxicological properties. Increasing interest is being directed toward developing high-performance sensors for continuous monitoring of DMZ in food samples. This research investigated an electrochemical sensor-based nano-sized ErVO attached to a sheet-like g-CN-coated glassy carbon electrode to determine dimetridazole (DMZ). The chemical structure and morphological characterization of synthesized ErVO@g-CN were analyzed with XRD, FTIR, TEM, and EDS. Irregular shapes of ErVO nanoparticles are approximately 15 nm. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were followed to examine the electrochemical performance in pH 7 phosphate buffer solution for higher performance. This electrochemical sensor showed a low detection limit (LOD) of 1 nM over a wide linear range of 0.5 to 863.5 µM. Also, selectivity, stability, repeatability, and reproducibility studies were investigated. Furthermore, this electrochemical sensor was applied to real-time milk sample analysis for the detection of analytes.
Topics: Animals; Vanadates; Erbium; Reproducibility of Results; Milk; Dimetridazole; Carbon; Electrochemical Techniques; Electrodes; Limit of Detection; Graphite; Nitrogen Compounds
PubMed: 38544072
DOI: 10.3390/s24061808 -
Micromachines Mar 2024Machining special microstructures on the surface of silicon nitride ceramics helps improve their service performance. However, the high brittleness and low fracture...
Machining special microstructures on the surface of silicon nitride ceramics helps improve their service performance. However, the high brittleness and low fracture toughness of silicon nitride ceramics make it extremely difficult to machine microstructures on their surface. In this study, a femtosecond laser is used to machine parallel grooved microstructures on the surface of silicon nitride ceramics. The effects of the laser polarization angle, laser single pulse energy, scanning line spacing, and laser scan numbers on the surface morphology and geometric characteristics of grooved microstructures are researched. It is found that a greater angle between the direction of the scanning path and laser polarization is helpful to obtain a smoother surface. As the single pulse energy increases, debris and irregular surface structures will emerge. Increasing the laser scan line spacing leads to clearer and more defined parallel grooved microstructures. The groove depth increases with the increase in the scan numbers. However, when a certain number of scans is reached, the depth will not increase further. This study serves as a valuable research foundation for the femtosecond laser processing of silicon nitride ceramic materials.
PubMed: 38542641
DOI: 10.3390/mi15030394 -
Physics in Medicine and Biology Apr 2024The successful implementation of FLASH radiotherapy in clinical settings, with typical dose rates >40 Gy s, requires accurate real-time dosimetry.Silicon carbide (SiC)...
The successful implementation of FLASH radiotherapy in clinical settings, with typical dose rates >40 Gy s, requires accurate real-time dosimetry.Silicon carbide (SiC) p-n diode dosimeters designed for the stringent requirements of FLASH radiotherapy have been fabricated and characterized in an ultra-high pulse dose rate electron beam. The circular SiC PiN diodes were fabricated at IMB-CNM (CSIC) in 3m epitaxial 4H-SiC. Their characterization was performed in PTB's ultra-high pulse dose rate reference electron beam. The SiC diode was operated without external bias voltage. The linearity of the diode response was investigated up to doses per pulse (DPP) of 11 Gy and pulse durations ranging from 3 to 0.5s. Percentage depth dose measurements were performed in ultra-high dose per pulse conditions. The effect of the total accumulated dose of 20 MeV electrons in the SiC diode sensitivity was evaluated. The temperature dependence of the response of the SiC diode was measured in the range 19 °C-38 °C. The temporal response of the diode was compared to the time-resolved beam current during each electron beam pulse. A diamond prototype detector (flashDiamond) and Alanine measurements were used for reference dosimetry.The SiC diode response was independent both of DPP and of pulse dose rate up to at least 11 Gy per pulse and 4 MGy s, respectively, with tolerable deviation for relative dosimetry (<3%). When measuring the percentage depth dose under ultra-high dose rate conditions, the SiC diode performed comparably well to the reference flashDiamond. The sensitivity reduction after 100 kGy accumulated dose was <2%. The SiC diode was able to follow the temporal structure of the 20 MeV electron beam even for irregular pulse estructures. The measured temperature coefficient was (-0.079 ± 0.005)%/°C.The results of this study demonstrate for the first time the suitability of silicon carbide diodes for relative dosimetry in ultra-high dose rate pulsed electron beams up to a DPP of 11 Gy per pulse.
Topics: Radiation Dosimeters; Radiometry; Silicon Compounds; Electrons; Carbon Compounds, Inorganic
PubMed: 38530300
DOI: 10.1088/1361-6560/ad37eb -
Physiology & Behavior May 2024The pathophysiology of atrial fibrillation and ventricular tachycardia that result in cardiac arrhythmias is related to the sustained complicated mechanisms of the... (Review)
Review
The pathophysiology of atrial fibrillation and ventricular tachycardia that result in cardiac arrhythmias is related to the sustained complicated mechanisms of the autonomic nervous system. Atrial fibrillation is when the heart beats irregularly, and ventricular arrhythmias are rapid and inconsistent heart rhythms, which involves many factors including the autonomic nervous system. It's a complex topic that requires careful exploration. Cultivation of speculative knowledge on atrial fibrillation; the irregular rhythm of the heart and ventricular arrhythmias; rapid oscillating waves resulting from mistakenly inconsistent P waves, and the inclusion of an autonomic nervous system is an inconceivable approach toward clinical intricacies. Autonomic modulation, therefore, acquires new expansions and conceptions of appealing therapeutic intelligence to prevent cardiac arrhythmia. Notably, autonomic modulation uses the neural tissue's flexibility to cause remodeling and, hence, provide therapeutic effects. In addition, autonomic modulation techniques included stimulation of the vagus nerve and tragus, renal denervation, cardiac sympathetic denervation, and baroreceptor activation treatment. Strong preclinical evidence and early human studies support the annihilation of cardiac arrhythmias by sympathetic and parasympathetic systems to transmigrate the cardiac myocytes and myocardium as efficient determinants at the cellular and physiological levels. However, the goal of this study is to draw attention to these promising early pre-clinical and clinical arrhythmia treatment options that use autonomic modulation as a therapeutic modality to conquer the troublesome process of irregular heart movements. Additionally, we provide a summary of the numerous techniques for measuring autonomic tone such as heart rate oscillations and its association with cutaneous sympathetic nerve activity appear to be substitute indicators and predictors of the outcome of treatment.
Topics: Humans; Atrial Fibrillation; Heart; Autonomic Nervous System; Sympathetic Nervous System; Heart Rate
PubMed: 38527577
DOI: 10.1016/j.physbeh.2024.114527 -
Advanced Science (Weinheim,... Jun 2024Harvesting renewable mechanical energy is envisioned as a promising and sustainable way for power generation. Many recent mechanical energy harvesters are able to...
Harvesting renewable mechanical energy is envisioned as a promising and sustainable way for power generation. Many recent mechanical energy harvesters are able to produce instantaneous (pulsed) electricity with a high peak voltage of over 100 V. However, directly storing such irregular high-voltage pulse electricity remains a great challenge. The use of extra power management components can boost storage efficiency but increase system complexity. Here utilizing the conducting polymer PEDOT:PSS, high-rate metal-free micro-supercapacitor (MSC) arrays are successfully fabricated for direct high-efficiency storage of high-voltage pulse electricity. Within an area of 2.4 × 3.4 cm on various paper substrates, large-scale MSC arrays (comprising up to 100 cells) can be printed to deliver a working voltage window of 160 V at an ultrahigh scan rate up to 30 V s. The ultrahigh rate capability enables the MSC arrays to quickly capture and efficiently store the high-voltage (≈150 V) pulse electricity produced by a droplet-based electricity generator at a high efficiency of 62%, significantly higher than that (<2%) of the batteries or capacitors demonstrated in the literature. Moreover, the compact and metal-free features make these MSC arrays excellent candidates for sustainable high-performance energy storage in self-charging power systems.
PubMed: 38502870
DOI: 10.1002/advs.202400697