209 research outputs found

    Sudden death caused by pulmonary fat embolism in a patient with miliary tuberculosis

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    An 84-year-old Japanese woman with myelodysplastic syndrome was admitted with pyrexia and dyspnea, but died suddenly during diagnostic evaluation. The autopsy revealed miliary tuberculosis in addition to myelodysplastic syndrome in the bone marrow. The immediate cause of the patient’s sudden death was pulmonary fat embolism derived from bone marrow necrosis. This case shows that the infiltration of the myelodysplastic bone marrow by tuberculosis and consequent bone marrow necrosis and fat embolism can be the cause of sudden death. In this article, we report the autopsy results of this unusual cause of sudden death, and discuss tuberculosis-related sudden death with a review of the literature

    Maximum Entropy Density Control of Discrete-Time Linear Systems with Quadratic Cost

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    This paper addresses the problem of steering the distribution of the state of a discrete-time linear system to a given target distribution while minimizing an entropy-regularized cost functional. This problem is called a maximum entropy (MaxEnt) density control problem. Specifically, the running cost is given by quadratic forms of the state and the control input, and the initial and final distributions are Gaussian. We first reveal that our problem boils down to solving two Riccati difference equations coupled through their boundary values. Based on them, we give the closed-form expression of the unique optimal policy. Next, we show that the optimal policy for the density control of the time-reversed system can be obtained simultaneously with the forward-time optimal policy. Finally, by considering the limit where the entropy regularization vanishes, we derive the optimal policy for the unregularized density control problem.Comment: 16 page

    Entropic Model Predictive Optimal Transport for Underactuated Linear Systems

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    This letter investigates dynamical optimal transport of underactuated linear systems over an infinite time horizon. In our previous work, we proposed to integrate model predictive control and the celebrated Sinkhorn algorithm to perform efficient dynamical transport of agents. However, the proposed method requires the invertibility of input matrices, which severely limits its applicability. To resolve this issue, we extend the method to (possibly underactuated) controllable linear systems. In addition, we ensure the convergence properties of the method for general controllable linear systems. The effectiveness of the proposed method is demonstrated by a numerical example.Comment: Published in IEEE Control Systems Letter

    Entropic model predictive optimal transport over dynamical systems

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    We consider the optimal control problem of steering an agent population to a desired distribution over an infinite horizon. This is an optimal transport problem over dynamical systems, which is challenging due to its high computational cost. In this paper, by using entropy regularization, we propose Sinkhorn MPC, which is a dynamical transport algorithm integrating model predictive control (MPC) and the so-called Sinkhorn algorithm. The notable feature of the proposed method is that it achieves cost-effective transport in real time by performing control and transport planning simultaneously, which is illustrated in numerical examples. Moreover, under some assumption on iterations of the Sinkhorn algorithm integrated in MPC, we reveal the global convergence property for Sinkhorn MPC thanks to the entropy regularization. Furthermore, focusing on a quadratic control cost, without the aforementioned assumption we show the ultimate boundedness and the local asymptotic stability for Sinkhorn MPC

    Stochastic model-based assessment of power systems subject to extreme wind power fluctuation

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    Extreme outliers of wind power fluctuation are a source of severe damage to power systems. In our previous work, we proposed a modelling framework, verified its usefulness via real data, and developed a model-based evaluation method of the impact of such extreme outliers. However, it has been a drawback that the obtained estimates of frequency fluctuation of power systems are sometimes excessively conservative for their practical use. To overcome this weakness, theory and methods for tightening the fluctuation estimates are investigated in this paper. This is done by applying a robust performance analysis method of a Lur'e system to the error analysis of stochastic linearization. The usefulness of our proposed method is shown through a load frequency control model

    Continuous perfusion of pulmonary arteries during total cardiopulmonary bypass favorably affects levels of circulating adhesion molecules and lung function

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    AbstractObjectives: Lung injury is a serious complication of cardiopulmonary bypass in infants with congenital heart disease and pulmonary hypertension. Cessation of blood flow in the pulmonary arteries during cardiopulmonary bypass is known to provoke lung dysfunction. We assessed the effect of continuous pulmonary perfusion on circulating adhesion molecules and on lung function. Methods: Fourteen infants with congenital heart disease and pulmonary hypertension were enrolled in the study. During total cardiopulmonary bypass, 8 patients underwent continuous perfusion of the pulmonary arteries (perfusion group), and the remaining 6 patients did not (control group). Plasma levels of circulating intercellular adhesion molecule 1, soluble granule membrane protein 140, and sialyl Lewisx and PaO2/fraction of inspired oxygen ratios were measured before commencement and serially for 24 hours after termination of bypass. Results: Plasma levels of circulating intercellular adhesion molecule 1 decreased significantly at the termination of bypass in both groups but returned to prebypass levels immediately in the control group, whereas in the perfusion group the values remained significantly less than those before bypass. Plasma levels of soluble granule membrane protein 140 in the control group were significantly higher at 6 and 12 hours after bypass than levels before bypass, whereas in the perfusion group the values remained at the prebypass level throughout the postbypass period. Trends of plasma levels of sialyl Lewisx were alike in both groups. PaO2/fraction of inspired oxygen ratios in the control group decreased significantly from 6 hours after bypass, whereas values in the perfusion group remained at the prebypass value throughout the postbypass period. Conclusions: This study suggests that in infants having congenital heart disease and pulmonary hypertension, continuous pulmonary perfusion during total cardiopulmonary bypass minimizes ischemic insult and neutrophil-endothelial interaction mediated by adhesion molecules in the pulmonary microvessels.J Thorac Cardiovasc Surg 2001;122:242-
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