Automated Design of Fault Diagnosis CNN Network for Satellite Attitude Control Systems.

Despite the dominance of unsupervised and self-supervised anomaly detection methods in the current satellite fault diagnosis domain, supervised anomaly detection offers a superior alternative for high-sensitivity detection and lightweight deployment requirements specific to subsystems or components, such as attitude control systems (ACSs). This article addresses the issues of over-design and insufficient accuracy in the CNN network design for satellite ACS fault diagnosis by introducing the modified particle swarm optimization-advanced convolution blocks-based CNN (MPSO-ACBCNN) method. First, we present the ACBCNN, a lightweight, flexible-layer CNN architecture. This architecture leverages advanced convolution blocks (ACBs), which incorporate numerous efficient design elements to enhance feature extraction capabilities within power spectral density (PSD) graphs of various fault samples, and employs classical dense connection methods to prevent the issue of gradient vanishing. Second, we devise the MPSO-ACBCNN algorithm to optimize the ACBCNN fault diagnosis architecture for specified ACS using MPSO. In MPSO-ACBCNN, several optimizations to the canonical PSO are implemented, including the fitness design that balances the tradeoff between total parameter quantity and the training effectiveness, and methods to ensure feasible solutions, etc. Finally, numerical experimental results demonstrate the effectiveness and superiority of MPSO-ACBCNN in fault diagnosis for ACS.

Early diagnosis, treatment, and outcomes of five patients with acute thallium poisoning.

BACKGROUND: Thallium poisoning is rare and difficult to recognize. Early diagnosis and treatment of thallium-poisoned patients are essential to prevent morbidity and mortality. AIM: To evaluate the efficacy of treatments and outcomes of five patients with early diagnosis of acute thallium poisoning. METHODS: Five patients who consumed a thallium-contaminated meal were hospitalized in succession, and underwent clinical examinations such as blood tests and electromyography tests. Urine and blood tests confirmed the diagnosis of thallotoxicosis, revealing the occurrence of food poisoning. All patients underwent detoxification treatment, including hemoperfusion (HP) and treatment with Prussian blue (PB). A 24-mo follow-up was performed to evaluate the long-term outcomes on the patients after discharge. RESULTS: Initially, the patients presented with symptoms of acute thallium poisoning including hyperalgesia of the limbs and abdominalgia, which may differ from common peripheral neuropathy. Accompanying symptoms such as hepatic damage and alopecia were observed in all the patients, which further confirmed the diagnosis of poisoning. Treatment with chelating agents was ineffective, while HP and treatment with PB drastically decreased the thallium concentration in the urine and blood. With early diagnosis and intervention, four patients had a good prognosis and no permanent sequelae. One patient developed blindness and disability during the 24-mo follow-up period. CONCLUSION: Identification of incident cluster and characteristic symptoms is extremely important for early diagnosis of acute thallium poisoning. HP plus PB is essential to improve the prognosis of thallium-poisoned patients.

Development, safety and efficacy of a novel circular-irrigated deca-channel mapping and ablation catheter for pulmonary vein isolation.

BACKGROUND: Pulmonary vein isolation (PVI), a cornerstone for catheter ablation of atrial fibrillation (AF), remains a complex and time-consuming procedure. Present study introduces a novel, circular-irrigated, deca-channel mapping and ablation catheter (CIDMA), describes the in vitro test results on feasibility, safety, and acute efficacy of the CIDMA catheter. METHODS: An assembled CIDMA catheter was subjected to a number of in vitro tests. With this catheter, ablation procedures were first performed in a pig's myocardial strips in vitro to determine the effects in unipolar or bipolar configuration. RESULTS: Three catheters were assembled. The adjustable circular diameter was changed from initial state of 32.41 ± 0.61 mm into controlled state of 28.61 ± 0.47 mm (P = 0.013). In the plastic model, the push-ability, torque-ability, and kink resistance of CIDMA catheter were shown to be satisfactory. In vitro, our findings showed that ablation could produce obvious ablation lesions, and unipolar ablation (at length, width and depth of 5.0 ± 1.3, 4.6 ± 0.7, and 4.2 ± 0.6 mm, respectively) was more effective than bipolar (at length, width and depth of 2.8 ± 0.2, 4.2 ± 0.5, and 2.3 ± 0.4 mm, respectively) (P < 0.01). CONCLUSIONS: In vitro, our preliminary data suggest that the CIDMA catheter produced optimal ablation lesions, especially in the unipolar ablation mode. Future in vivo animal and clinical studies are warranted to test the efficacy of this catheter in real-world scenario.

Blood rheology of angina pectoris patients with myocardial injury after ischemia reperfusion and its effect on thromboxane B2 levels.

This study investigated the changes in the blood rheology of patients with angina pectoris and ischemia reperfusion injury and their effect on thromboxane B2 (TXB2) levels to examine their relationship. Forty patients with unstable angina pectoris who underwent elective percutaneous coronary intervention (PCI) were selected for the unstable angina group (UA group) and forty patients deemed free of coronary heart disease by coronary angiography were selected for the control group. Venous blood samples were drawn from all participants; patients in the UA group had blood drawn 1 day before and 1 day after the PCI procedure. Blood samples were used to analyze blood rheology and examine hemodynamic parameters, at the same time radioimmunoassay was applied to measure the concentrations of serum endothelin-1 (ET-1) and TXB2, and an automatic biochemical analyzer was used to detect the content of superoxide dismutase (SOD) and malondialdehyde (MDA). Our results showed the patients in the UA group all presented hyperviscosity; however the levels were higher for the patients in the UA group (after surgery) than for those in the UA group (before surgery). Patients in the control group exhibited normal levels, and the differences among groups were significant in pairwise comparisons (P<0.05). The levels of ET-1 and TXB2 in the UA group were increased compared with those in control group and they were highest after surgery (P<0.05). For the patients in the UA group, the serum TXB2 concentration increased gradually along with the increase in risk stratification. There were significant differences in comparisons between different strata and between UA patients and those in the control group (P<0.05). The serum SOD activity levels were lowest in the UA group (after surgery), higher in the UA group (before surgery) and highest in the control group. Conversely, the MDA content was highest in the UA group (after surgery), lower in the UA group (before surgery) and smallest in the control group; there were significant differences in pairwise comparisons. Based on our findings, a hyperviscosity syndrome was manifested in the blood rheology of patients with angina pectoris and ischemia reperfusion injury. The higher than normal TXB2 levels can be used as a marker of platelet activation and a reference for clinical risk stratification, thus having great significance for the prevention and treatment of ischemia reperfusion injury and assessment of disease progression.

[Investigations on registration for three-dimensional mapping of cardiac chambers and computed tomography segmented images].

In this paper, a novel registration method is presented for three-dimensional mapping of cardiac chambers and computed tomography (CT) segmented surfaces. The proposed method applies random perturbations to three-dimensional mapping of cardiac chambers in order to move out of local minima. It effectively solves the problem of the existing algorithm based on iterative closest point (ICP) in which the optimization often falls into local minima, and improves the registration accuracy and success rate. The registration experiment results show that the final registration accuracy and success rate of the proposed method are better than the existing ICP-based algorithm, and it can implement the registration when the three-dimensional mapping of cardiac chambers and CT segmented surface have a wide range of initial offset.

3-D reconstruction of the coronary artery tree from multiple views of a rotational X-ray angiography.

To present an efficient and robust method for 3-D reconstruction of the coronary artery tree from multiple ECG-gated views of an X-ray angiography. 2-D coronary artery centerlines are extracted automatically from X-ray projection images using an enhanced multi-scale analysis. For the difficult data with low vessel contrast, a semi-automatic tool based on fast marching method is implemented to allow manual correction of automatically-extracted 2-D centerlines. First, we formulate the 3-D symbolic reconstruction of coronary arteries from multiple views as an energy minimization problem incorporating a soft epipolar line constraint and a smoothness term evaluated in 3-D. The proposed formulation results in the robustness of the reconstruction to the imperfectness in 2-D centerline extraction, as well as the reconstructed coronary artery tree being inherently smooth in 3-D. We further propose to solve the energy minimization problem using α-expansion moves of Graph Cuts, a powerful optimization technique that yields a local minimum in a strong sense at a relatively low computational complexity. We show experimental results on a synthetic coronary phantom, a porcine data set and 11 patient data sets. For the coronary phantom, results obtained using different number of views are presented. 3-D reconstruction error evaluated by the mean plus one standard deviation is below one millimeter when 4 or more views are used. For real data, reconstruction using 4 to 5 views and 256 depth labels averaged around 12 s on a computer with 2.13 GHz Intel Pentium M and achieves a mean 2-D back-projection error of 1.18 mm (ranging from 0.84 to 1.71 mm) in 12 cases. The accuracy for multi-view reconstruction of the coronary artery tree as reported from the phantom and patient studies is promising, and the efficiency is significantly improved compared to other approaches reported in the literature, which range from a few to tens of minutes. Visually good and smooth reconstruction is demonstrated.

Image guidance of intracardiac ultrasound with fusion of pre-operative images.

This paper presents a method for registering 3D intracardiac echo (ICE) to pre-operative images. A magnetic tracking sensor is integrated on the ICE catheter tip to provide the 3D location and orientation. The user guides the catheter into the patient heart to acquire a series of ultrasound images covering the anatomy of the heart chambers. An automatic intensity-based registration algorithm is applied to align these ultrasound images with pre-operative images. One of the important applications is to help electrophysiology doctors to treat complicated atrial fibrillation cases. After registration, the doctor can see the position and orientation of the ICE catheter and other tracked catheters inside the heart anatomy in real time. The image guidance provided by this technique may increase the ablation accuracy and reduce the amount of time for the electrophysiology procedures. We show successful image registration results from animal experiments.

On simulating subjective evaluation using combined objective metrics for validation of 3D tumor segmentation.

In this paper, we present a new segmentation evaluation method that can simulate radiologist's subjective assessment of 3D tumor segmentation in CT images. The method uses a new metric defined as a linear combination of a set of commonly used objective metrics. The weighing parameters of the linear combination are determined by maximizing the rank correlation between radiologist's subjective rating and objective measurements. Experimental results on 93 lesions demonstrate that the new composite metric shows better performance in segmentation evaluation than each individual objective metric. Also, segmentation rating using the composite metric compares well with radiologist's subjective evaluation. Our method has the potential to facilitate the development of new tumor segmentation algorithms and assist large scale segmentation evaluation studies.

Point fingerprint: a new 3-D object representation scheme.

This paper proposes a new, efficient surface representation method for surface matching. A feature carrier for a surface point, which is a set of two-dimensional (2-D) contours that are the projections of geodesic circles on the tangent plane, is generated. The carrier is named point fingerprint because its pattern is similar to human fingerprints and plays a role in discriminating surface points. Corresponding points on surfaces from different views are found by comparing their fingerprints. The point fingerprint is able to carry curvature, color, and other information which can improve matching accuracy, and the matching process is faster than 2-D image comparison. A novel candidate point selection method based on the fingerprint irregularity is introduced. Point fingerprint is successfully applied to pose estimation of real range data.