Severe/critical COVID-19 early warning system based on machine learning algorithms using novel imaging scores

BACKGROUND Early identification of severe/critical coronavirus disease 2019(COVID-19)is crucial for timely treatment and intervention.Chest computed tomography(CT)score has been shown to be a significant factor in the diagnosis and treatment of pneumonia,however,there is currently a lack of effective early warning systems for severe/critical COVID-19 based on dynamic CT evolution.AIM To develop a severe/critical COVID-19 prediction model using a combination of imaging scores,clinical features,and biomarker levels.METHODS This study used an improved scoring system to extract and describe the chest CT characteristics of COVID-19 patients.The study also took into consideration the general clinical indicators such as dyspnea,oxygen saturation,alternative lengthening of telomeres(ALT),and androgen suppression treatment(AST),which are commonly associated with severe/critical COVID-19 cases.The study employed lasso regression to evaluate and rank the significance of different disease characteristics.RESULTS The results showed that blood oxygen saturation,ALT,IL-6/IL-10,combined score,ground glass opacity score,age,crazy paving mode score,qsofa,AST,and overall lung involvement score were key factors in predicting severe/critical COVID-19 cases.The study established a COVID-19 severe/critical early warning system using various machine learning algorithms,including XGBClassifier,Logistic Regression,MLPClassifier,RandomForestClassifier,and AdaBoost Classifier.The study concluded that the prediction model based on the improved CT score and machine learning algorithms is a feasible method for early detection of severe/critical COVID-19 evolution.CONCLUSION The findings of this study suggest that a prediction model based on improved CT scores and machine learning algorithms is effective in detecting the early warning signals of severe/critical COVID-19.

Efficient Phase Locking of Fiber Amplifiers Using a Low-Cost and High-Damage-Threshold Phase Control System

We propose a low-cost and high-damage-threshold phase control system that employs a piezoelectric ceramic transducer modulator controlled by a stochastic parallel gradient descent algorithm. Efficient phase locking of two fiber amplifiers is demonstrated. Experimental results show that energy encircled in the target pinhole is increased by a factor of 1.76 and the visibility of the fringe pattern is as high as 90% when the system is in close-loop. The phase control system has potential in phase locking of large-number and high-power fiber laser endeavors.

Cryptanalysis and Improvement of Quantum Secret Sharing Protocol between Multiparty and Multiparty with Single Photons and Unitary Transformations

In a recent paper [Yan F L et al. Chin.Phys.Lett. 25（2008）1187], a quantum secret sharing the protocol between multiparty and multiparty with single photons and unitary transformations was presented. We analyze the security of the protocol and find that a dishonest participant can eavesdrop the key by using a special attack. Finally, we give a description of this strategy and put forward an improved version of this protocol which can stand against this kind of attack.

General Theory of Decoy-State Quantum Cryptography with Dark Count Rate Fluctuation

The existing theory of decoy-state quantum cryptography assumes that the dark count rate is a constant, but in practice there exists fluctuation. We develop a new scheme of the decoy state, achieve a more practical key generation rate in the presence of fluctuation of the dark count rate, and compare the result with the result of the decoy-state without fluctuation. It is found that the key generation rate and maximal secure distance will be decreased under the influence of the fluctuation of the dark count rate.

Three-Dimensional Finite Element Analysis of Phase Change Memory Cell with Thin TiO2 Film

A thin TiO2 layer inserted in a phase change memory （PCM） cell to form a deep sub-micro bottom electrode （DBE） is proposed and its electro-thermal characteristics are investigated with the three-dimensional finite element analysis. Compared with the conventional PCM cell with a SiN stop layer, the reset threshold current of the PCM cell with the TiO2 layer is reduced from 1.8 mA to 1.2 mA and the ratio of the amorphous resistance and crystalline resistive increases from 65 to 100. The optimum thickness of the TiO2 layer and the optimum height of DBE are 10nm and 200nm, respectively. Therefore, the PCM cell with the TiO2 layer can decrease the programming power consumption and increase heating efficiency. The TiO2 film is a better candidate for the SiN film in the PCM cell structure to prepare DBE and to reduce programming power in the reset operation.

Cryptanalysis of an Improved Flexible Ping-Pong Protocol in Perfect and Imperfect Quantum Channels

We recently proposed a flexible quantum secure direct communication protocol [Chin. Phys. Lett. 23 （2006） 3152]. By analyzing its security in the perfect channel from the aspect of quantum information theory, we find that an eavesdropper is capable of stealing all the information without being detected. Two typical attacks are presented to illustrate this point. A solution to this loophole is also suggested and we show its powerfulness against the most general individual attack in the ideal case. We also discuss the security in the imperfect case when there is noise and loss.

Evaluation of coronary artery bypass graft patency using three-dimensional reconstruction and flow study of electron beam tomography

Objective To establish and evaluate two protocols for the noninvasive visualization and assessment of coronary artery bypass graft (CABG) patency on electron beam tomography (EBT).Methods Two hundred and fourteen consecutive patients who underwent coronary artery bypass graft surgery were scanned using both EBT angiography with 3-dimensional reconstruction and EBT flow study with time-density-curve analysis.Results There were 589 CABGs evaluated in this study (10 grafts were excluded because of artifacts). Among them, 133 (98.5％) of 135 arterial grafts were patent, and 345 (77.7％) of 444 saphenous-vein grafts were patent. Within 5 years or between 5 and 10 years after operation, arterial graft patency exceeded venous graft patency (P ＜ 0.001 ). Three-dimensional EBT angiography achieved higher sensitivity, specificity and accuracy (97.7％, 94.1％ and 96.7％, respectively) than did EBT flow study (88.4％, 82.4％ and 85.2％, respectively) for evaluating occlusion or patency of CABG. The intra-graft flow of patent arterial and venous grafts were 4.9 ± 2.2 mi · min-1 · g-1 and 6.9 ± 2.8 mi · min-1 · g-1,respectively (P＜0.001).Conclusion The combination of EBT three-dimensional reconstruction and flow study can be more effective in the assessment of CABG anatomy and quantification of patent CABG blood flow.

Evolution of computers and simulations: from science and technology to the foundations of society

We consider the relevance of computer hardware and simulations not only to science and technology but also to social life. Evolutionary processes are part of all we know, from the physical and inanimate world to the simplest or most complex biological system. Evolution is manifested by land mark discoveries which deeply affect our social life. Demographic pressure, demand for improved living standards and devastation of the natural environment pose new and complex challenges. We believe that the implementation of new computational models based on the latest scientific methodology can provide a reasonable chance of overcoming today's social problems. To ensure this goal, however, we need a change of mindset, placing findings obtained from modern science above traditional concepts and beliefs. In particular, the type of modeling used with success in computational sciences must be extended to allow simulations of novel models for social life.