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On August 6, 2023, a magnitude MW5.5 earthquake struck Pingyuan County, Dezhou City, Shandong Province, China. This event was significant as no large earthquakes had been recorded in the region for over a century, and no active fault had been previously identified. This study collects 1309 P-wave arrival times and 866 S-wave arrival times from 74 seismic stations less than 200 km to the epicenter to constrain the spatial distribution of the mainshock and its 125 early aftershocks by the double difference earthquake relocation method, and selects 864 P-waveforms from 288 stations located within 800 km of the epicenter to constrain the focal mechanism solution of the mainshock through centroid moment tensor inversion. The relocation and the inversion indicate, the Pingyuan MW5.5 earthquake was caused by a rupture on a buried fault, likely an extensive segment of the Gaotang fault. This buried fault exhibited a dip of approximately 75° to the northwest, with a strike of 222°, similar to the Gaotang fault. The rupture initiated at the depth of 18.6 km and propagated upward and northeastward. However, the ground surface was not broken. The total duration of the rupture was ~6.0 s, releasing the scalar moment of 2.589 5 × 1017 N·m, equivalent to MW5.54. The moment rate reached the maximum only 1.4 seconds after the rupture initiation, and the 90% scalar moment was released in the first 4.6 s. In the first 1.4 seconds of the rupture process, the rupture velocity was estimated to be 2.6 km/s, slower than the local S-wave velocity. As the rupture neared its end, the rupture velocity decreased significantly. This study provides valuable insights into the seismic characteristics of the Pingyuan MW5.5 earthquake, shedding light on the previously unidentified buried fault responsible for the seismic activity in the region. Understanding the behavior of such faults is crucial for assessing seismic hazards and enhancing earthquake preparedness in the future. [ABSTRACT FROM AUTHOR]

In many organisms, γ-glutamylmethylamide is a significant amino acid constituent. In this research, a novel method of γ-glutamylmethylamide synthesis is presented. The synthesis of γ-glutamylmethylamide was catalysed by immobilized recombinant γ-glutamyltranspeptidase and used L-glutamylhydrazine as an economical substrate. The optimal enzymes and γ-glutamyltranspeptidase reaction conditions for the production of γ-glutamylmethylamide were 200 mM L-glutamylhydrazine, 1 M methylamine, and 0.1 g/ml immobilized γ-glutamyltranspeptidase cells at pH 10 and 37 °C for 10 h. The immobilized γ-glutamyltranspeptidase cells were used for 10 reactions, and the average conversion ratio from L-glutamylhydrazine to γ-glutamylmethylamide reached 93.2%. The activity of immobilized recombinant γ-glutamyltransferase was not inhibited by 200 mM L-glutamylhydrazine. The immobilized γ-glutamyltranspeptidase cells exhibited favourable operational stability. [ABSTRACT FROM AUTHOR]

Magnetic detection electrical impedance tomography (MDEIT) is an imaging modality that aims to compute the cross-sectional distribution of the conductivity of a volume from the magnetic flux density surrounding the object. Owing to the Biot-Savart law, the MDEIT inverse problem is inherently ill-conditioned making image reconstruction highly susceptible to the effects of noise and numerical errors. Appropriate priors or penalties are needed to facilitate reconstruction and to restrict the search space to a specific solution set. The images have the sparsity property and sharp variations. Consequently, this paper presents an approach involving a combination of the L¹ and total variation norm penalties, the former to suppress spurious background signals and enforce sparsity and the latter to preserve local smoothness and piecewise constancy in the MDEIT reconstructed images. The primal dual-interior point method (PD-IPM) for minimizing the joint L¹--TV penalty was used in the paper. The method was validated by using MDEIT simulated data and experimental data in comparison with the performances of the L², L¹ and total variation norm penalty-based approaches. The results show that the joint L¹--TV regularized algorithm preserves sparsity property, local smoothness and piecewise constancy, leading to improvements in the localization of the reconstructed images in MDEIT. [ABSTRACT FROM AUTHOR]

Magnetic resonance electrical impedance tomography (MREIT) is a noninvasive modality to visualize the internal electrical conductivity distribution of an electrically conductive object using a magnetic resonance imaging (MRI) scanner. The impedance tomography step may provide valuable additional information that cannot be recovered from the MR reconstruction. Previous research has been mostly performed on the reconstruction algorithms and the measurement system. However, the anatomical information provided by the MR images is not in full use. This paper proposes an image reconstruction method based on anatomical information which provides the prior knowledge. The sensitivity algorithm with generalized minimum residual (GMRES) is proposed to reconstruct conductivity image. Simulations of a realistic geometry leg model are performed to show that our approach is not only capable of achieving high accuracy, but also able to improve the speed of the image reconstruction. At the end, a preliminary phantom experiment is presented, illustrating the feasibility of this proposed method. [ABSTRACT FROM AUTHOR]

In order to remotely monitor the activities of heartbeat, respiration and body movement, this article designed and implemented a single-channel nonorthogonal in-phase/quadrature (I/Q) RF sensor, which works at the central frequency of 2.4 GHz. The designed RF sensor is based on a printed circuit board (PCB) antenna. Taking into account low cost, simple structure and easy fabrication, the antenna is designed and implemented with a special broad-band microstrip-tocoplanar strip line Balun structure by combining the transmitter with the receiver on a PCB to form one single antenna system. The gain of the sensor is 7.7 dB. The return loss is -22.7 dB at 2.4 GHz and the directionality of the antenna is satisfactory for monitoring vital signs. It has been validated that the designed sensor can detect the respiration, heartbeat and body movement accurately in comparison with the signals acquired by respiration sensor and pulse sensor. [ABSTRACT FROM AUTHOR]

Because arterial pulse waves contain vital information related to the condition of the cardiovascular system, considerable attention has been devoted to the study of pulse waves in recent years. Accurate acquisition is essential to investigate arterial pulse waves. However, at the stage of developing equipment for acquiring and analyzing arterial pulse waves, specific pulse signals may be unavailable for debugging and evaluating the system under development. To produce test signals that reflect specific physiological conditions, in this paper, an arterial pulse wave generator has been designed and implemented using a field programmable gate array (FPGA), which can produce the desired pulse waves according to the feature points set by users. To reconstruct a periodic pulse wave from the given feature points, a method known as piecewise Gaussian-cosine fitting is also proposed in this paper. Using a test database that contains four types of typical pulse waves with each type containing 25 pulse wave signals, the maximum residual error of each sampling point of the fitted pulse wave in comparison with the real pulse wave is within 8%. In addition, the function for adding baseline drift and three types of noises is integrated into the developed system because the baseline occasionally wanders, and noise needs to be added for testing the performance of the designed circuits and the analysis algorithms. The proposed arterial pulse wave generator can be considered as a special signal generator with a simple structure, low cost and compact size, which can also provide flexible solutions for many other related research purposes. [ABSTRACT FROM AUTHOR]

Pulse wave contains much information on a cardiovascular system. Pulse wave variability during exercise is of great significance as it reflects more information combining with pulse wave under stationary state. This paper studied the morphology variability of radial pulse wave during exercise. Radial pulse waves were collected from 30 subjects with two pressure pulse sensors worn at the wrists of the right and left hands, respectively. Electrocardiography (ECG) was also detected synchronously. After data preprocessing and feature point extraction, the variability of several parameters of pulse wave and ECG were analyzed. It is notable that pulse rate (PR) and heart rate (HR) change synchronously. During the exercise period, both systolic phase and diastolic phase of a radial pulse shorten but the latter is more obvious. The amplitude of the dicrotic notch decreases and even turns negative. Aligning the radial pulse waveforms together, the radial pulse waveforms prior to, during and after exercise coincide with each other except for some details like the tidal wave which fades away during exercise. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the clinical features of ulcerative colitis (UC) combined with acute interstitial lung disease (ILD). One case with acute UC combined with ILD and airway disease was reported, and the pathological diagnosis of previous cases of UC combined with ILD was retrospectively analyzed according to the corresponding literature. The present case concerned a male patient with UC who presented with dry cough and progressive dyspnea. The chest computed tomography (CT) images showed as normal on the seventh day; diffuse ground.glass shadows were observed on the 11th day and diffuse reticular, patchy, nodular shadows and lung cysts were observed on the 21st day. The results of an open lung biopsy on the 23rd day indicated pleural adhesions, and the pathologies were pulmonary fibrosis and airway inflammation. Glucocorticoid therapy was ineffective in the patient, but cyclophosphamide combined with γ globulin rapidly caused the disease to remit. A total of 24 cases with UC combined with ILD and two cases of UC combined with acute ILD were retrieved through PubMed. UC combined with acute ILD was rare in clinical practice. Patients with dry cough, progressive dyspnea and diffuse ground-glass shadows in pulmonary CT images should be closely monitored. Glucocorticoid therapy should be carefully selected and precautions should be taken against opportunistic infections of the lung. Cyclophosphamide combined with γ globulin may be an effective treatment strategy. [ABSTRACT FROM AUTHOR]

The aim of the present study was to investigate the regulatory mechanism of nuclear factor (NF)-κB on polymorphonuclear neutrophil (PMN) accumulation and the inflammatory response in lung tissues with acute respiratory distress syndrome (ARDS), as well as the therapeutic effect of pyrrolidine dithiocarbamate (PDTC). Mouse models of ARDS were established by intraperitoneal injection of lipopolysaccharide (LPS). BALB/c mice were divided into control, LPS and PDTC + LPS groups. The expression of PMN adhesion molecules, CD11b/CD18 and intercellular adhesion molecule-1 (ICAM-1), were detected by immunohistochemistry, while the protein expression levels of NF-κB p65 in the lung tissue were analyzed by western blot analysis. In addition, flow cytometry was used to investigate the apoptosis rate of PMNs in the bronchoalveolar fluid, and the expression levels of interleukin (IL)-1β, IL-8 and tumor necrosis factor (TNF)-a and myeloperoxidase (MPO) activity were also determined. Following an intraperitoneal injection of LPS, alveolar septum rupture, pulmonary interstitial hyperemia and PMN infiltration in the alveolar was observed. The protein expression of p65 in the pulmonary cytoplasm decreased, while the expression of p65 in the nucleus increased. The levels of IL-8, IL-1β and TNF-a increased and the high expression status was maintained for 24 h. As the time increased, CD11b/CD18 and ICAM-1 expression increased, as well as MPO activity, while the apoptosis of PMNs was delayed. Compared with the LPS group, the expression of p65 in the pulmonary cytoplasm and the PMN apoptosis rate increased following PDTC intervention, while the expression of p65 in the nucleus decreased, as well as the expression levels of the cytokines and MPO activity. Therefore, PDTC reduced the production of inflammatory cytokines via the NF-κB pathway, which reduced the activation of PMNs in the lung tissue and promoted PMN apoptosis. [ABSTRACT FROM AUTHOR]

Analysis of pulse waveform is a low cost, non-invasive method for obtaining vital information related to the conditions of the cardiovascular system. In recent years, different Pulse Decomposition Analysis (PDA) methods have been applied to disclose the pathological mechanisms of the pulse waveform. All these methods decompose single-period pulse waveform into a constant number (such as 3, 4 or 5) of individual waves. Furthermore, those methods do not pay much attention to the estimation error of the key points in the pulse waveform. The estimation of human vascular conditions depends on the key points' positions of pulse wave. In this paper, we propose a Multi-Gaussian (MG) model to fit real pulse waveforms using an adaptive number (4 or 5 in our study) of Gaussian waves. The unknown parameters in the MG model are estimated by the Weighted Least Squares (WLS) method and the optimized weight values corresponding to different sampling points are selected by using the Multi-Criteria Decision Making (MCDM) method. Performance of the MG model and the WLS method has been evaluated by fitting 150 real pulse waveforms of five different types. The resulting Normalized Root Mean Square Error (NRMSE) was less than 2.0% and the estimation accuracy for the key points was satisfactory, demonstrating that our proposed method is effective in compressing, synthesizing and analyzing pulse waveforms. [ABSTRACT FROM AUTHOR]

In this paper, approximate entropy (ApEn) is applied to study the variability of pulse waveform for assessing coronary arteriosclerosis status. Having analyzed the wrist pulse waveforms taken from both normal subjects and the patients suffering from coronary arteriosclerosis (CA) disorders, we find that pulse morphology variability (PMV) is more efficient than pulse interval variability (PIV) in assessing the conditions of human coronary artery. Usually, the PMVs of the healthy are higher than those of the patients with CA diseases, and the PMVs of patients with CA diseases have more high frequency components than those of the healthy subjects. That is to say, the CA disease also has influence on vascular tone. The effect of changes in cardiac performance due to CA disease can be reflected through the PMV. The experiment demonstrates that the specificity and sensitivity of the PMV’s spectral energy ratio for clinical diagnosis of cardiovascular system is 80% and 97%, respectively. [ABSTRACT FROM AUTHOR]

In order to assess the sensitivities of the radiation characteristics and the compliance of ingestible wireless device (IWD) in human body due to the uncertainty and intersubject variability of dielectric properties of human body tissues, the specific absorption rate (SAR) and radiation characteristics of the IWD in two realistic human body models with changed and unchanged dielectric values are quantitatively compared using the finite-difference time-domain method. Simulations are carried out in 13 scenarios where the IWD is placed in the center positions of abdomens in the two body models at the operating frequency of 430 MHz with three orientations. Results show that the variation of radiation intensity near the surface of abdomen is around 2.5 dB within 20% variation of dielectric values. The maximum SAR values increase with the increase in conductivities of human body tissues and decrease with the increase in relative permittivities of human body tissues. A variation of up to 20% in conductivities and relative permittivities, alone or simultaneously, always causes a variation of SAR to be less than 10%. As far as the compliance of safety is concerned, the maxima of 1-g-averaged and 10-g-averaged SARs can reach 3.16 and 0.89 W/kg at the input power of 25 mW. [ABSTRACT FROM AUTHOR]

This paper presents an energy ratio-based method and a wavelet-based cascaded adaptive filter (CAF) for detecting and removing baseline drift from pulse waveforms. Experiments on 50 simulated and five hundred real pulse signals demonstrate that this CAF outperforms traditional filters both in removing baseline drift and in preserving the diagnostic information of pulse waveforms. [ABSTRACT FROM AUTHOR]

We conducted rapid inversions of rupture process for the 2023 earthquake doublet occurred in SE Türkiye, the first with a magnitude of MW7.8 and the second with a magnitude of MW7.6, using teleseismic and strong-motion data. The teleseismic rupture models of the both events were obtained approximately 88 and 55 minutes after their occurrences, respectively. The rupture models indicated that the first event was an asymmetric bilateral event with ruptures mainly propagating to the northeast, while the second one was a unilateral event with ruptures propagating to the west. This information could be useful in locating the meizoseismal areas. Compared with teleseismic models, the strong-motion models showed relatively higher resolution. A noticeable difference was found for the MW7.6 earthquake, for which the strong-motion models shows a bilateral event, rather than a unilateral event, but the dominant rupture direction is still westward. Nevertheless, all strong-motion models are consistent with the teleseismic models in terms of magnitudes, durations, and dominant rupture directions. This suggests that both teleseismic and strong-motion data can be used for fast determination of major source characteristics. In contrast, the strong-motion data would be preferable in future emergency responses since they are recorded earlier and have a better resolution ability on the source ruptures. [ABSTRACT FROM AUTHOR]

Objective: To investigate the possibility of false‑negative occurrence of non‑specific benign pathological results on CT‑guided transthoracic lung core‑needle biopsy and identify risk factors for false‑negative results. Methods: The clinical, imaging, and surgical data of 403 lung biopsy patients were retrospectively analyzed. Patients were divided into true‑negative and false‑negative (FN) groups according to the final diagnosis. Univariate analysis was used to compare the variables in two groups for statistical differences, and multivariate analysis was used to clarify the risk factors associated with FN results. Results: Of the 403 lesions, 332 were finally confirmed as benign and 71 to be malignant, with a FN rate of 17.6%. Older patient age (P = 0.01), burr sign (P = 0.00), and pleural traction sign (P = 0.02) were independent risk factors for FN results. The area under the receiver operating characteristic (ROC) curve’s area under curve (AUC) was 0.73. Conclusion: CT‑guided transthoracic lung core‑needle biopsy has a high diagnostic accuracy and low rate of FN results. Older patient age, the burr sign, and the pleural traction sign are independent risk factors for FN results that should be monitored prior to surgery to reduce the risk of FN results. [ABSTRACT FROM AUTHOR]

Magnetic detection electrical impedance tomography (MDEIT) is an imaging modality that aims to reconstruct the cross-sectional conductivity distribution of a volume from the magnetic flux density surrounding an object. The MDEIT inverse problem is inherently ill-posed, necessitating the use of regularization. The most commonly used L² norm regularizations generate the minimum energy solution, which blurs the sharp variations of the reconstructed image. Consequently, this paper presents the total variation (TV) regularization to preserve discontinuities and piecewise constancy of the MDEIT reconstructed image. The primal dual-interior point method (PD-IPM) is employed for minimizing the TV penalty in this paper. The proposed method is validated by MDEIT simulated data. In comparison with the performance of L² norm regularization, the results show that TV regularized algorithm produces sharper images and has better robustness to noise. The TV regularized algorithm preserves local smoothness and piecewise constancy, leading to improvements in the localization of the reconstructed conductivity images in MDEIT. [ABSTRACT FROM AUTHOR]

One-dimensional viscous behavior of clay was evaluated by performing drained one-dimensional compression tests, and drained triaxial compression tests. In both types of tests, the strain rate was changed stepwise many times and creep tests were performed several times during otherwise monotonic primary loading, unloading, and reloading. The specimens were: (1) saturated specimens of undisturbed clays; (2) normally consolidated saturated clay specimens reconstituted by consolidating slurry of clay chips from undisturbed samples and clay powder; and (3) specimens prepared by compacting wet, air-dried, and oven-dried powder of several different clay types. One-dimensional viscous behavior, which can be described with β value of clay, is significant in all types of clay specimens. The observed viscous behavior of clay specimens is successfully simulated by a nonlinear three-component rheology model of the isotach type. [ABSTRACT FROM AUTHOR]

Objective: Remote photoplethysmography (rPPG) can achieve non-contact measurement of heart rate (HR) from a continuous video sequence by scanning the skin surface. However, practical applications are still limited by factors such as non-rigid facial motion and head movement. In this work, a detailed system framework for remotely estimating heart rate from facial videos under various movement conditions is described. Approach: After the rPPG signal has been obtained from a defined region of the facial skin, a method, termed ‘Project_ICA’, based on a skin reflection model, is employed to extract the pulse signal from the original signal. Main results: To evaluate the performance of the proposed algorithm, a dataset containing 112 videos including the challenges of various skin tones, body motion and HR recovery after exercise was created from 28 participants. Significance: The results show that Project_ICA, when evaluated by several criteria, provides a more accurate and robust estimate of HR than most existing methods, although problems remain in obtaining reliable measurements from dark-skinned subjects. [ABSTRACT FROM AUTHOR]

Non-contact method to monitor vital signs using radar-based sensor system is a more convenient way in comparison with the contact monitoring devices. Portable with a low profile and low-cost non-contact vital signs sensors system that are capable to monitor heart and respiration rates are presented and evaluated their performances. A printed 2x1 patch array antenna, Yagi-Uda antenna and dipole array antenna are designed and integrated with sensor system Tx/Rx module for their performances analysis. The gain of the designed antennas are 6.38 dBi, 7.7 dBi, and 10.5 dBi, VSWR are 1.1, 1.15, and 1.0, and return loss are -26.26 dB, -22.7 dB and -21.6 dB respectively at 2.4 GHz. The evaluations performances of these antennas were compared with a standard respiratory-rate measurement using a pulse sensor and respiratory sensor. The measurement results using the proposed non-contact sensor systems and the standard contact systems showed excellent performance with the printed dipole array antenna compared with other two antennas, the error between the average heart rate extracted by the non-contact systems and the reference systems are ±1.1 beat/min for dipole array antenna, ±1.5 beat/min for printed 2x1 patch array antenna and ±1.9 beat/min for Yagi-Uda antenna. [ABSTRACT FROM AUTHOR]

Synchronous acquisition of multi-channel biopotential signals, such as electrocardiograph (ECG) and electroencephalograph, has vital significance in health care and clinical diagnosis. In this paper, we proposed a new method which is using single channel ADC to acquire multi-channel biopotential signals modulated by square waves synchronously. In this method, a specific modulate and demodulate method has been investigated without complex signal processing schemes. For each channel, the sampling rate would not decline with the increase of the number of signal channels. More specifically, the signal-tonoise ratio of each channel is n times of the time-division method or an improvement of 3.01 x log2n dB, where n represents the number of the signal channels. A numerical simulation shows the feasibility and validity of this method. Besides, a newly developed 8-lead ECG based on the new method has been introduced. These experiments illustrate that the method is practicable and thus is potential for low-cost medical monitors. [ABSTRACT FROM AUTHOR]

The endothelial cells (ECs) lining of a blood vessel wall are exposed to both the wall shear stress (WSS) of blood flow and the circumferential strain (CS) of pulsing artery wall motion. Both WSS and CS keep involved in the modulation of ECs’ biochemical response and function and the temporal phase angle between the two is called stress phase angle (SPA). Previous studies at the cellular level have indicated that SPA is highly negative at sites that are prone to atherosclerosis, and hypothesized that large SPA may contribute to atherogenesis. Till now, there is no experimental data to support this hypothesis, probably due to the lack of a proper tool for measuring WSS and CS simultaneously and real time. In this study, a non-invasive ultrasonic biomechanics method was utilized to quantitatively calculate the SPA and experimentally evaluate the role of SPA in predicting early atherosclerosis. Three silicon tubes with a stiffness of 1.15, 3.62, 9.38 MPa were assembled in a pulsatile flow circuit and the values of SPA were measured to be −101.86 ± 3.65°,−170.19 ± 17.77° and −260.63 ± 18.62°, respectively. For the PVA-c phantoms, stiffness was 162.45, 235.68 and 374.24 kPa, the SPA corresponding to −170.32 ± 17.55°,−207.56 ± 10.78° and −261.08 ± 10.90°, respectively. Both phantom studies results demonstrated that SPA was highly negative in stiffer arteries. Further, experiments were taken in healthy living rats as control group (n = 3), atherosclerotic model group (n = 3), and drug treated group (n = 3), and the results showed that SPA was most negative in the model group, and SPA was least negative in the control group. Together, this study suggested that highly negative SPA appeared to be a prominent mechanical feature of vessels prone to atherosclerotic disease. [ABSTRACT FROM AUTHOR]