Price discovery in Chinese PVC futures and spot markets: Impacts of COVID-19 and benchmark analysis.

Despite being a minor futures category, Polyvinyl chloride (PVC) futures have emerging as a vital element in energy and chemical futures domain. Employing three benchmark models component share (CS), information share (IS), and information leadership share (ILS), this study explores the price discovery function of Chinese PVC futures and spot markets. It assesses whether PVC futures have matured into an effective hedging tool and reference point for spot markets, and also examines the impact of the COVID-19 pandemic on this price discovery relationship. Empirical analysis reveals that the futures market has become the primary site for price discovery in the Chinese PVC market. All the models consistently demonstrate a mature price discovery function in PVC futures, providing risk mitigation tools for industry players. However, post-pandemic dynamics indicate that price discovery in PVC markets primarily occurs within the spot market. This suggests that compared to the futures market, the PVC spot market is able to respond more quickly to the strong signals of industrial recovery after the end of the pandemic. The feedback and pricing efficiency of the PVC futures market in response to new market information are also influenced. Furthermore, our study offers better anticipation of future market prices.

Successful Use of a 5G-Based Robot-Assisted Remote Ultrasound System in a Care Center for Disabled Patients in Rural China.

Background: Disability has become a global population health challenge. Due to difficulties in self-care or independent living, patients with disability mainly live in community-based care centers or institutions for long-term care. Nonetheless, these settings often lack basic medical resources, such as ultrasonography. Thus, remote ultrasonic robot technology for clinical applications across wide regions is imperative. To date, few experiences of remote diagnostic systems in rural care centers have been reported. Objective: To assess the feasibility of a fifth-generation cellular technology (5G)-based robot-assisted remote ultrasound system in a care center for disabled patients in rural China. Methods: Patients underwent remote robot-assisted and bedside ultrasound examinations of the liver, gallbladder, spleen, and kidneys. We compared the diagnostic consistency and differences between the two modalities and evaluated the examination duration, image quality, and safety. Results: Forty-nine patients were included (21 men; mean age: 61.0 ± 19.0 [range: 19-91] years). Thirty-nine and ten had positive and negative results, respectively; 67 lesions were detected. Comparing the methods, 41 and 8 patients had consistent and inconsistent diagnoses, respectively. The McNemar and kappa values were 0.727 and 0.601, respectively. The mean duration of remote and bedside examinations was 12.2 ± 4.5 (range: 5-26) min and 7.5 ± 1.8 (range: 5-13) min (p < 0.001), respectively. The median image score for original images on the patient side and transmitted images on the doctor side was 5 points (interquartile range: [IQR]: 4.7-5.0) and 4.7 points (IQR: 4.5-5.0) (p = 0.176), respectively. No obvious complications from the examination were reported. Conclusions: A 5G-based robot-assisted remote ultrasound system is feasible and has comparable diagnostic efficiency to traditional bedside ultrasound. This system may provide a unique solution for basic ultrasound diagnostic services in primary healthcare settings.

A two-stage multiresolution neural network for automatic diagnosis of hepatic echinococcosis from ultrasound images: A multicenter study.

PURPOSE: Hepatic echinococcosis is a parasitic disease. Ultrasound imaging is a crucially important tool for the diagnosis of this disease. Based on ultrasonic manifestations, hepatic echinococcosis can be classified into many subtypes. However, subtyping is nontrivial due to the challenges of complex sonographic textures and large intraclass and small interclass differences. The purpose of this study is to develop a computer-aided diagnosis system for hepatic echinococcosis based on ultrasound images. METHODS: We collected a multicenter ultrasound dataset containing 9112 images from 5028 patients who were diagnosed with hepatic echinococcosis (the largest cohort to date) and developed a two-stage multiresolution neural network for the automatic diagnosis of hepatic echinococcosis into nine subtypes, as suggested by the WHO. Our method was based on YOLO3 with two additional strategies to improve its performance: coarse grouping and multiresolution sampling. Considering that some subtypes are inherently very similar and difficult to differentiate; in the first stage, we detected and classified lesions into four coarse groups instead of making a direct classification into nine classes. In the second stage, we performed fine-grained classification within each coarse group. Multiple views with different resolutions were sampled from the detected lesions and were input into Darknet53. The softmax outputs for the multiresolution views were averaged to generate the final output. RESULTS: Both the proposed coarse grouping and multiresolution sampling strategies proved to be effective and improved the classification performance by a large margin compared with the setting without using the two strategies. Using fivefold cross-validation, our method achieved 87.1%, 86.2%, and 86.5% in the average recall, precision and F1-score, respectively, and outperformed other state-of-the-art methods remarkably. CONCLUSIONS: The experimental results demonstrate the great promise of our method for classifying hepatic echinococcosis. Our method can be used as an effective tool to facilitate large-scale screening for hepatic echinococcosis in high-risk, resource-poor areas, thus contributing to the early diagnosis of this disease and resulting in more successful treatment.

A DNA dendrimer amplified electrochemical immunosensing method for highly sensitive detection of prostate specific antigen.

This work designed a DNA dendrimer for the loading of signal molecule and the construction of amplified electrochemical immunosensing method. The DNA dendrimer was self-assembled by the hybridization of one couple of complementary oligonucleotides (DNA and cDNA) that were covalently conjugated to three arms of a Y-shaped cross-linker, tris(2-maleimidoethyl)amine (TMEA) respectively. The immunosensor was prepared by coating chitosan on glassy carbon electrode to covalently immobilize the capture antibody with glutaraldehyde as a linker. After the target protein was captured on the immunosensor, cDNA-labeled secondary antibody was bound on the surface via a sandwiched immunoreaction to introduce the DNA dendrimer onto immunosensor for loading abundant methylene blue as signal molecule, which amplified greatly the amperometric signal for immunoassay. Using prostate specific antigen (PSA) as a model analyte, this proposed method showed a wide linear range from 1 pg mL-1 to 10 ng mL-1 along with a limit of detection down to 0.26 pg mL-1. The designed strategy avoided complex synthesis of signal tags, and possessed excellent performance for analysis of practical samples, thus providing a new avenue for the development of signal amplification strategy and immunoassay methods.

Feasibility of a 5G-Based Robot-Assisted Remote Ultrasound System for Cardiopulmonary Assessment of Patients With Coronavirus Disease 2019.

BACKGROUND: Traditional methods for cardiopulmonary assessment of patients with coronavirus disease 2019 (COVID-19) pose risks to both patients and examiners. This necessitates a remote examination of such patients without sacrificing information quality. RESEARCH QUESTION: The goal of this study was to assess the feasibility of a 5G-based robot-assisted remote ultrasound system in examining patients with COVID-19 and to establish an examination protocol for telerobotic ultrasound scanning. STUDY DESIGN AND METHODS: Twenty-three patients with COVID-19 were included and divided into two groups. Twelve were nonsevere cases, and 11 were severe cases. All patients underwent a 5G-based robot-assisted remote ultrasound system examination of the lungs and heart following an established protocol. Distribution characteristics and morphology of the lung and surrounding tissue lesions, left ventricular ejection fraction, ventricular area ratio, pericardial effusion, and examination-related complications were recorded. Bilateral lung lesions were evaluated by using a lung ultrasound score. RESULTS: The remote ultrasound system successfully and safely performed cardiopulmonary examinations of all patients. Peripheral lung lesions were clearly evaluated. Severe cases of COVID-19 had significantly more diseased regions (median [interquartile range], 6.0 [2.0-11.0] vs 1.0 [0.0-2.8]) and higher lung ultrasound scores (12.0 [4.0-24.0] vs 2.0 [0.0-4.0]) than nonsevere cases of COVID-19 (both, P < .05). One nonsevere case (8.3%; 95% CI, 1.5-35.4) and three severe cases (27.3%; 95% CI, 9.7-56.6) were complicated by pleural effusions. Four severe cases (36.4%; 95% CI, 15.2-64.6) were complicated by pericardial effusions (vs 0% of nonsevere cases, P < .05). No patients had significant examination-related complications. INTERPRETATION: Use of the 5G-based robot-assisted remote ultrasound system is feasible and effectively obtains ultrasound characteristics for cardiopulmonary assessment of patients with COVID-19. By following established protocols and considering medical history, clinical manifestations, and laboratory markers, this system might help to evaluate the severity of COVID-19 remotely.

Pilot Study of Robot-Assisted Teleultrasound Based on 5G Network: A New Feasible Strategy for Early Imaging Assessment During COVID-19 Pandemic.

Early diagnosis is critical for the prevention and control of the coronavirus disease 2019 (COVID-19). We attempted to apply a protocol using teleultrasound, which is supported by the 5G network, to explore the feasibility of solving the problem of early imaging assessment of COVID-19. Four male patients with confirmed or suspected COVID-19 were hospitalized in isolation wards in two different cities. Ultrasound specialists, located in two other different cities, carried out the robot-assisted teleultrasound and remote consultation in order to settle the problem of early cardiopulmonary evaluation. Lung ultrasound, brief echocardiography, and blood volume assessment were performed. Whenever difficulties of remote manipulation and diagnosis occurred, the alternative examination was repeated by a specialist from another city, and in sequence, remote consultation was conducted immediately to meet the consensus. The ultrasound specialists successfully completed the telerobotic ultrasound. Lung ultrasound indicated signs of pneumonia with varying degrees in all cases and mild pleural effusion in one case. No abnormalities of cardiac structure and function and blood volume were detected. Remote consultation on the issue of manipulation practice, and the diagnosis in one case was conducted. The cardiopulmonary information was delivered to the frontline clinicians immediately for further treatment. The practice of teleultrasound protocol makes early diagnosis and repeated assessment available in the isolation ward. Ultrasound specialists can be protected from infection, and personal protective equipment can be spared. Quality control can be ensured by remote consultations among doctors. This protocol is worth consideration as a feasible strategy for early imaging assessment in the COVID-19 pandemic.

Colorimetric Detection of Nucleic Acids through Triplex-Hybridization Chain Reaction and DNA-Controlled Growth of Platinum Nanoparticles on Graphene Oxide.

The controllable growth of metal nanoparticles on nanomaterials is becoming a useful strategy for developing nanocomposites with designated performance. Here, a DNA-controlled strategy for growth of Pt nanoparticles on graphene oxide (GO-PtNPs) to regulate the nanozyme activity and a triplex-hybridization chain reaction (tHCR) for triggering the assembly of DNA probes to amplify the target-induced nanozyme catalytic signal were designed. The tHCR with one linear and two hairpin probes could be specially triggered by a tHCR trigger to form a long double-stranded DNA structure in the presence of target nucleic acid, which hindered the adsorption of these probes on a GO surface, and thus accelerated the growth of PtNPs. The formed GO-PtNPs showed strong catalytic activity toward the oxidation of 3,3,5,5-tetramethylbenzidine, thereby producing an amplified "turn-on" detection signal. The proposed method showed very high sensitivity with the detection limits down to 14.6 pM for mutant KRAS DNA and 21.7 pM for let-7a microRNA. This method was validated with better analytical performance than a general HCR system and could be effectively used for the identification of single-nucleotide polymorphisms, thus providing a novel approach for simple and sensitive detection of nucleic acids.

Shared control of a medical robot with haptic guidance.

PURPOSE: Tele-operation of robotic surgery reduces the radiation exposure during the interventional radiological operations. However, endoscope vision without force feedback on the surgical tool increases the difficulty for precise manipulation and the risk of tissue damage. The shared control of vision and force provides a novel approach of enhanced control with haptic guidance, which could lead to subtle dexterity and better maneuvrability during MIS surgery. METHODS: The paper provides an innovative shared control method for robotic minimally invasive surgery system, in which vision and haptic feedback are incorporated to provide guidance cues to the clinician during surgery. The incremental potential field (IPF) method is utilized to generate a guidance path based on the anatomy of tissue and surgical tool interaction. Haptic guidance is provided at the master end to assist the clinician during tele-operative surgical robotic task. RESULTS: The approach has been validated with path following and virtual tumor targeting experiments. The experiment results demonstrate that comparing with vision only guidance, the shared control with vision and haptics improved the accuracy and efficiency of surgical robotic manipulation, where the tool-position error distance and execution time are reduced. CONCLUSIONS: The validation experiment demonstrates that the shared control approach could help the surgical robot system provide stable assistance and precise performance to execute the designated surgical task. The methodology could also be implemented with other surgical robot with different surgical tools and applications.

Modeling of human artery tissue with probabilistic approach.

Accurate modeling of biological soft tissue properties is vital for realistic medical simulation. Mechanical response of biological soft tissue always exhibits a strong variability due to the complex microstructure and different loading conditions. The inhomogeneity in human artery tissue is modeled with a computational probabilistic approach by assuming that the instantaneous stress at a specific strain varies according to normal distribution. Material parameters of the artery tissue which are modeled with a combined logarithmic and polynomial energy equation are represented by a statistical function with normal distribution. Mean and standard deviation of the material parameters are determined using genetic algorithm (GA) and inverse mean-value first-order second-moment (IMVFOSM) method, respectively. This nondeterministic approach was verified using computer simulation based on the Monte-Carlo (MC) method. Cumulative distribution function (CDF) of the MC simulation corresponds well with that of the experimental stress-strain data and the probabilistic approach is further validated using data from other studies. By taking into account the inhomogeneous mechanical properties of human biological tissue, the proposed method is suitable for realistic virtual simulation as well as an accurate computational approach for medical device validation.

Modeling and simulation of material degradation in biodegradable wound closure devices.

Biodegradable materials have been used as wound closure materials. It is important for these materials to enhance wound healing when the wound is vulnerable, and maintain wound closure until the wound is heal. This article studies the degradation process of bioresorbable magnesium micro-clips for wound closure in voice/laryngeal microsurgery. A novel computational approach is proposed to model degradation of the biodegradable micro-clips. The degradation process that considers both material and geometry of the device as well as its deployment is modeled as an energy minimization problem that is iteratively solved using active contour and incremental finite element methods. Strain energy of the micro-clip during degradation is calculated with the stretching and bending functions in the active contour formulation. The degradation rate is computed from strain energy using a transformation formulation. By relating strain energy to material degradation, the degradation rates and geometries of the micro-clip during degradation can be represented using a simulated degradation map. Computer simulation of the degradation of the micro-clip presented in the study is validated by in vivo and in vitro experiments.

Reality based modeling and simulation of gallbladder shape deformation using variational methods.

PURPOSE: Accurate soft tissue deformation modeling is important for realistic surgical simulation. The aim of this study is to develop a reality-based gallbladder model and to determine material constants that represent gallbladder wall mechanical properties. METHODS: Mechanical experiments on porcine gallbladder were performed to investigate tissue deformation, and an exponential strain energy function was used to describe the nonlinear stress-strain behavior of the gallbladder wall. A new volumetric function based upon the exponential strain energy function was proposed to model the gallbladder organ. A genetic algorithm was used to identify the material parameters of the proposed biomechanical model from the experimental data. RESULTS: The material constants of the exponential strain energy model were determined based on the experimental data. Deformation simulation and haptic rendering using the proposed gallbladder model were presented. Comparison between deformation predicted by the proposed model and that of the experimental data on gallbladder wall and gallbladder organ tissues demonstrates the applicability of this reality-based variational method for deformation simulation. CONCLUSION: An accurate soft tissue deformation model was developed using material constants identified for gallbladder. The model is suitable for interactive haptic rendering and deformation simulation. This model has potential applications for simulation of other hollow organs.