Solving Coupled Differential Equation Groups Using PINO-CDE

As a fundamental mathmatical tool in many engineering disciplines, coupled differential equation groups are being widely used to model complex structures containing multiple physical quantities. Engineers constantly adjust structural parameters at the design stage, which requires a highly efficient solver. The rise of deep learning technologies has offered new perspectives on this task. Unfortunately, existing black-box models suffer from poor accuracy and robustness, while the advanced methodologies of single-output operator regression cannot deal with multiple quantities simultaneously. To address these challenges, we propose PINO-CDE, a deep learning framework for solving coupled differential equation groups (CDEs) along with an equation normalization algorithm for performance enhancing. Based on the theory of physics-informed neural operator (PINO), PINO-CDE uses a single network for all quantities in a CDEs, instead of training dozens, or even hundreds of networks as in the existing literature. We demonstrate the flexibility and feasibility of PINO-CDE for one toy example and two engineering applications: vehicle-track coupled dynamics (VTCD) and reliability assessment for a four-storey building (uncertainty propagation). The performance of VTCD indicates that PINO-CDE outperforms existing software and deep learning-based methods in terms of efficiency and precision, respectively. For the uncertainty propagation task, PINO-CDE provides higher-resolution results in less than a quarter of the time incurred when using the probability density evolution method (PDEM). This framework integrates engineering dynamics and deep learning technologies and may reveal a new concept for CDEs solving and uncertainty propagation

FI-CEUS: a solution to improve the diagnostic accuracy in MRI LI-RADS-indeterminate (LR-3/4) FLLs at risk for HCC

ObjectiveTo evaluate the diagnostic accuracy of fusion imaging contrast-enhanced ultrasound (FI-CEUS) of magnetic resonance imaging (MRI) LI-RADS-indeterminate (LR-3/4) and conventional ultrasound undetected focal liver lesions (FLLs) in patients at risk for hepatocellular carcinoma (HCC).MethodsBetween February 2020 and July 2021, 71 FLLs in 63 patients were registered for diagnostic performance evaluation respectively for ultrasound-guided thermal ablation evaluation in this retrospective study. Diagnostic performance regarding FLLs was compared between FI-CEUS and contrast-enhanced MRI (CE-MRI).ResultsFor diagnostic performance evaluation, among 71 lesions in 63 patients, the diagnostic efficacy of FI-CEUS with LI-RADS was significantly higher than that of CE-MRI (P < 0.05) in both overall and hierarchical comparison (except for the group with lesion diameter ≥2 cm). For malignant lesions, the proportion of arterial phase hyperenhancement (APHE) and washout on FI-CEUS was higher than that on CE-MRI (P < 0.05).ConclusionFI-CEUS has a high value in the precise qualitative diagnosis of small FLLs (<2 cm) of MRI LI-RADS-indeterminate diagnosis (LR-3/4) that are undetected by conventional ultrasound in patients at risk for HCC and can be a good supplementary CE-MRI diagnostic method for thermal ablation evaluation

Thermal ablation as an alternative to liver transplantation for hepatocellular carcinoma with clinically significant portal hypertension: propensity score matching study

PurposeThe objectives were to investigate the safety and efficacy of thermal ablation as an alternative to liver transplantation for hepatocellular carcinoma patients with clinically significant portal hypertension (CSPH).Materials and MethodsFrom July 2016 to September 2019, hepatocellular carcinoma patients with CSPH treated by liver transplantation (N=37) or thermal ablation (N=114) were enrolled. Cumulative intrahepatic recurrence, overall survival and major complications were compared by propensity score matching.ResultsIn the two matched groups, the 1-, 2-, and 3-year intrahepatic recurrence rates for the ablation group (22.3%, 50.0%, and 50.0%, respectively) were significantly higher than those for the transplantation group (4.5%, 4.5%, and 4.5%, respectively) (P=0.016). The 1-, 2-, and 3-year overall survival rates were comparable between the two groups [96.1%, 88.7%, and 88.7%, respectively (ablation group) vs. 84.6%, 76.2%, and 76.2%, respectively (transplantation group)] (P=0.07). The major complication rate for the ablation group [4.8% (3/62)] was significantly lower than that for the transplantation group [36.0% (9/25)] (P<0.001).ConclusionsThermal ablation is a safe and effective alternative for hepatocellular carcinoma patients with CSPH

Efficiency Comparison of Public Hospitals under Different Administrative Affiliations in China: A Pilot City Case

This study seeks to measure the efficiency disparity and productivity change of tertiary general public hospitals in Wuhan city, central China from the perspective of administrative affiliations by using panel data from 2013 to 2017. Sample hospitals were divided into three categories, namely provincial hospitals, municipal hospitals, and other levels of hospitals. Data envelopment analysis with bootstrapping technique was used to estimate efficiency scores, and a sensitive analysis was performed by varying the specification of model by considering undesirable outputs to test robustness of estimation, and efficiency evolution analysis was carried out by using the Malmquist index. The results indicated that the average values of provincial hospitals and municipal hospitals have experienced efficiency improvement over the period, especially after the initiation of Pilot Public Hospital Reform, but hospitals under other affiliations showed an opposite trend. Meanwhile, differences of administrative subordination in technical efficiency of public hospitals emerged, and the disparity was likely to grow over time. The higher efficiency of hospitals affiliated with municipality, as compared with those governed by province and under other administrative affiliations, may be attributed to better governance and organization structure

Study on the influencing factors of space charge dynamic behavior in XLPE insulation under alternating current electric field

International audienceAbstract The dynamic behavior of space charges is one of the potential factors that cause electrical aging. In this paper, a bipolar space charge transport model was established under an AC electric field in cross-linked polyethylene. The effects of physical parameters on the dynamic behavior of space charges in an AC electric field were explored by changing the injection barrier heights, mobilities, trapping coefficients, and detrapping barrier heights of positive and negative charges. The effects of voltage conditions on space charge behavior were explored by changing the amplitude and frequency. The effects of temperature were studied by setting a temperature gradient similar to that of real cable operation. The asymmetry of the physical parameters could seriously aggravate the accumulation of space charges in the AC field. A set of physical parameters based on these results was identified. Both the increase in voltage amplitude and decrease in frequency enhanced the amount of and penetration into the insulation of the accumulated space charge. The dynamic behaviors of the space charges were more active with increased voltage amplitude and frequency. The temperature gradient in the cable insulation implies that the degree of accumulation, penetration into material, and activity of dynamic behaviors of the space charges at the warmest electrode are greater than those at the coldest. Compared with the DC field, the dynamic behavior of space charges in the AC electric field is more active and releases more energy. This research provides a theoretical basis for inhibiting the accumulation of space charges in an AC electric field

An Epstein-Barr Virus Positive Lymphoepithelioma-Like Cholangiocarcinoma in A Young Woman with Chronic Hepatitis B Treated through Microwave Ablation: A Case Report and Literature Review

Lymphoepithelioma-like cholangiocarcinoma (LELCC) is a rare subtype of carcinoma that is poorly reported. We report a case of LELCC in a 28-year-old female with chronic hepatitis B. She underwent secondary microwave ablation for residual tumor following the failure of radiofrequency ablation (RFA). Image fusion technology was used to accurately diagnose that the second lesion represented residual tumor. This case is the second successful application of microwave ablation in the treatment of LELCC. We first reviewed the ultrasonographic features of LELCC. We report this case to improve our understanding of this disease and provide evidence for its clinical treatment

A Better Fruit Quality of Grafted Blueberry Than Own-Rooted Blueberry Is Linked to Its Anatomy

To further clarify the impact of different rootstocks in grafted blueberry, fruit quality, mineral contents, and leaf gas exchange were investigated in ‘O’Neal’ blueberry (Vaccinium corymbosum) grafted onto ‘Anna’ (V. corymbosum) (AO), ‘Sharpblue’ (V. corymbosum) (SO), ‘Baldwin’ (V. virgatum) (BO), ‘Plolific’ (V. virgatum) (PO), and ‘Tifblue’ (V. virgatum) (TO) rootstocks and own-rooted ‘O’Neal’ (NO), and differences in anatomic structures and drought resistance were determined in AO, TO, and NO. The findings revealed that fruit quality in TO and PO was excellent, that of BO and SO was good, and that of AO and NO was medium. ‘Tifblue’ and ‘Plolific’ rootstocks significantly increased the levels of leaf phosphorus and net photosynthetic rate of ‘O’Neal’, accompanied by a synchronous increase in their transpiration rates, stomatal conductance, and intercellular CO2. Additionally, the comprehensive evaluation scores from a principal component analysis based on anatomic structure traits from high to low were in the order TO > AO > NO. The P50 (xylem water potential at 50% loss of hydraulic conductivity) values of these grafted plants descended in the order NO > AO > TO, and the branch hydraulic conductivity of TO and sapwood hydraulic conductivity of TO and AO were significantly lower than those of NO. Thus, TO plants exhibited the strongest drought resistance, followed by AO, and NO, and this trait was related to the effects of different rootstocks on the fruit quality of ‘O’Neal’ blueberry. These results provided a basis for a deeper understanding of the interaction between rootstocks and scions, as well mechanisms to improve blueberry fruit quality

The Influence of Physical Parameters on Space Charge Accumulation and Phase Characteristics in Cable Insulation under ac Electric Field

International audienceThe space charge dynamic behavior and accumulation are important contributions to electrical tree aging, as recognized for crosslinked polyethylene (XLPE) cable insulation under alternating current (ac) electric stress. In this paper, in order to investigate the reason for the charge accumulation phenomenon revealed by experiments under ac stress, a bipolar space charge transport model with symmetrical or asymmetrical parameters is resolved under ac stress. The charge accumulation mechanism is analyzed based on position and amount of charge function of voltage application time and voltage phase. The effects of each major physical parameter are simulated and analyzed separately. It is found that there is no obvious accumulation of space charges with symmetrical parameters. Asymmetrical parameters result in a difference of motion process between positive and negative charges, which greatly enhances charge accumulation. Each main parameter has an influence on charge accumulation from different angles and levels. The applicability of the simulation model with asymmetrical parameters is assessed by comparing experiments and simulation results on space charge. This study contributes to the understanding of space charge generation mechanism under ac conditions and helps improving the stability and operation properties of XLPE cables in power system

One-lung ventilation for percutaneous thermal ablation of liver tumors in the hepatic dome

Purpose To investigate the feasibility, efficacy and safety of one-lung ventilation for percutaneous thermal ablation of liver tumors in the hepatic dome. Materials and methods From 5 January 2017 to 16 April 2019, 64 patients who underwent ultrasound-guided thermal ablation with a total of 75 liver malignant tumors located in the hepatic dome were enrolled in the present study. One-lung ventilation was employed to improve the acoustic window and protect the lung and diaphragm. If the one-lung ventilation was unsuccessful, artificial pleural effusion was added. The technical efficacy was confirmed by contrast-enhanced computed tomography/magnetic resonance imaging (CT/MRI) 1 month later. After that, CT/MRI was performed every 3–6 months. Results Among the enrolled patients, the technical success rate of one lung ventilation was 92.2% (59/64). The visibility scores of tumors were improved significantly after one-lung ventilation compared to those before one-lung ventilation (p < .001). Finally, 78.6% (55/70) of the tumors achieved clinical success of one-lung ventilation to become clearly visible and underwent thermal ablation. Fourteen of the remaining 15 tumors achieved a satisfactory acoustic window after combination of artificial pleural effusion. One lesion remained inconspicuous and partly affected by pulmonary gas. The follow-up period was 8 months (3–30 months). The technical efficacy rate was confirmed to be 100% (75/75). During the follow-up period, local tumor progression occurred in 2 patients (2/75, 2.7%). Major complications occurred in two patients (2/64, 3.1%) receiving one-lung ventilation. Conclusions One-lung ventilation is a promising noninvasive method for the thermal ablation of hepatic dome tumors due to its efficacy and safety

Multicenter Analysis of Liver Injury Patterns and Mortality in COVID-19

Background and Aim: Liver test abnormalities are common in COVID-19 patients. The aim of our study was to determine risk factors for different liver injury patterns and to evaluate the relationship between liver injury patterns and prognosis in patients with COVID-19.Methods: We retrospectively analyzed patients admitted between January 1st to March 10th, with laboratory-confirmed COVID-19 and followed them up to April 20th, 2020. Information of clinical features of patients was collected for analysis.Results: As a result, a total of 838 hospitalized patients with confirmed COVID-19, including 48.8% (409/838) patients with normal liver function and 51.2% (429/838) patients with liver injury were analyzed. Abnormal liver function tests are associated with organ injuries, hypoxia, inflammation, and the use of antiviral drugs. Hepatocellular injury pattern was associated with hypoxia. The mortality of the hepatocellular injury pattern, cholestatic pattern and mixed pattern were 25, 28.2, and 22.3%, respectively, while the death rate was only 6.1% in the patients without liver injury. Multivariate analyses showed that liver injury with cholestatic pattern and mixed pattern were associated with increased mortality risk.Conclusions: Our study confirmed that hepatocellular injury pattern that may be induced by hypoxia was not risk factor for mortality in SARS-COV-2 infection, while liver injury with mixed pattern and cholestatic pattern that might be induced by SARS-CoV-2 directly might be potential risk factors for increased mortality in COVID-19 patients