An energy-saving control strategy based on predictive control for central air-conditioning systems is proposed in this paper. The cold load model is developed to describe the dynamic characteristics of temperature con...An energy-saving control strategy based on predictive control for central air-conditioning systems is proposed in this paper. The cold load model is developed to describe the dynamic characteristics of temperature control systems, and then parameters in the cold load model and in the central air-conditioning system model are estimated. Generalized predictive control (GPC) is used to establish an optimization model to minimize the consumption of energy and the control error of temperature. The simulated annealing (SA) algorithm, combined with quadratic programming, is adopted to solve the optimal problem. Contrasted with the simulation of traditional PID control, the results prove the effectiveness of this proposed strategy.展开更多
Septic shock is a common critical condition, for which effective early fluid resuscitation is the therapeutic focus. According to the 2008 international guidelines for management of severe sepsis and septic shock, res...Septic shock is a common critical condition, for which effective early fluid resuscitation is the therapeutic focus. According to the 2008 international guidelines for management of severe sepsis and septic shock, resuscitation should achieve a central venous pressure （CVP） of 8-12 mmHg within the first 6 h. However, it is still uncertain about the sensitivity and specificity of CVP in reflecting the cardiac preload. Ultrasonography is a simple, rapid, non-invasive, and repeatable method for the measurement of sensitivity and specificity of CVP and has thus gradually attracted the increasing attention of physicians. It was reported that ultrasonography can show the inferior vena cava diameter, respiratory variability index, and blood volume in patients with sepsis or heart failure.展开更多
Adaptive servo-ventilation(ASV) has been developed as a specific treatment for sleep-disordered breathing, in particular Cheyne-Stokes respiration with central sleep apnea(CSA). Heart failure patients often have sleep...Adaptive servo-ventilation(ASV) has been developed as a specific treatment for sleep-disordered breathing, in particular Cheyne-Stokes respiration with central sleep apnea(CSA). Heart failure patients often have sleep-disordered breathing, which consists of either obstructive sleep apnea(OSA) or CSA. Other medical conditions, such as stroke, acromegaly, renal failure, and opioid use may be associated with CSA. Continuous positive airway pressure(CPAP) therapy is widely used for patients with OSA, but some of these patients develop CSA on CPAP, which is called treatmentemergent CSA. CPAP can be useful as a treatment for these various forms of CSA, but it is insufficient to eliminate respiratory events in approximately half of patients with CSA. As compared to CPAP, ASV may be a better option to treat CSA, with sufficient alleviation of respiratory events as well as improvement of cardiac function in heart failure patients. In patients without heart failure, ASV can also alleviate CSA and relieve their symptom. Recently, ASV has been widely used for patients with various forms of CSA. ASV may be also used in the setting without CSA, but it should be assessed more carefully. Clinicians should have a better understanding of the indications for ASV in each setting.展开更多
The systemic administration of morphine affects ventilation via a mixture of central and peripheral actions. The aims of this study were to characterize the ventilatory responses elicited by a low dose of morphine in ...The systemic administration of morphine affects ventilation via a mixture of central and peripheral actions. The aims of this study were to characterize the ventilatory responses elicited by a low dose of morphine in conscious rats;to determine whether tolerance develops to these responses;and to determine the potential roles of peripheral μ-opioid receptors (μ-ORs) in these responses. Ventilatory parameters were monitored via unrestrained whole-body plethysmography. Conscious male Sprague-Dawley rats received an intravenous injection of vehicle or the peripherally-restricted μ-OR antagonist, naloxone methiodide (NLXmi), and then three successive injections of morphine (1 mg/kg) given 30 min apart. The first injection of morphine in vehicle-treated rats elicited an array of ventilatory excitant (i.e., increases in frequency of breathing, minute volume, respiratory drive, peak inspiratory and expiratory flows, accompanied by decreases in inspiratory time and end inspiratory pause) and inhibitory (i.e., a decrease in tidal volume and an increase in expiratory time) responses. Subsequent injections of morphine elicited progressively and substantially smaller responses. The pattern of ventilatory responses elicited by the first injection of morphine was substantially affected by pretreatment with NLXmi whereas NLXmi minimally affected the development of tolerance to these responses. Low-dose morphine elicits an array of ventilatory excitant and depressant effects in conscious rats that are subject to the development of tolerance. Many of these initial actions of morphine appear to involve activation of peripheral μ-ORs whereas the development of tolerance to these responses does not.展开更多
Heart failure (HF) is known to be associated with sleep-disordered breathing(SDB). In addition to disturbing patients’ sleep, SDB is also associated with a deterioration in the cardiac function and an increased morta...Heart failure (HF) is known to be associated with sleep-disordered breathing(SDB). In addition to disturbing patients’ sleep, SDB is also associated with a deterioration in the cardiac function and an increased mortality and morbidity.Central sleep apnea (CSA), typically characterized by Cheyne-Stokes breathing(CSB), is increasingly found in patients with HF compared to the general population. An important pathogenetic factor of CSA seen in HF patients is an instability in the control of the respiratory system, characterized by both hypocapnia and increased chemosensitivity. Sympathetic overactivation,pulmonary congestion and increased chemosensitivity associated with HF stimulate the pulmonary vagal irritant receptor, resulting in chronic hyperventilation and hypocapnia. Additionally, the repetitive apnea and arousal cycles induce cyclic sympathetic activation, which may worsen the cardiac prognosis. Correcting CSB may improve both patient’s quality of life and HF syndrome itself. However, a treatment for HF in patients also experiencing CSA is yet to be found. In fact, conflicting results from numerous clinical studies investigating sleep apnea with HF guide to a troubling question, that is whether(or not) sleep apnea should be treated in patients with HF? This editorial attempts to both collect the current evidence about randomized control trials investigating CSA in patients with HF and highlight the effect of specific CSA treatments on cardiovascular endpoints.展开更多
This research evaluates the performance of a Phase Change Material(PCM)battery integrated into the climate system of a new transparent meeting center.The main research questions are:a.“Can the performance of the batt...This research evaluates the performance of a Phase Change Material(PCM)battery integrated into the climate system of a new transparent meeting center.The main research questions are:a.“Can the performance of the battery be calculated?”and b.“Can the battery reduce the heating and cooling energy demand in a significant way?”The first question is answered in this document.In order to be able to answer the second question,especially the way the heat loading in winter should be improved,then more research is necessary.In addition to the thermal battery,which consists of Phase Change Material plates,the climate system has a cross-flow heat exchanger and a heat pump.The battery should play a central role in closing the thermal balance of the lightweight building,which can be loaded with hot return or cold outdoor air.The temperature of the battery plates is monitored by multi-sensors and simulated by the use of PHOENICS(Computational Fluid Dynamics)and MATLAB.This paper reports reasonable agreement between the numerical predictions and the measurements,with a maximum variance of 10%.The current coefficient of performance for heating and cooling is already high,more than 27.There is scope for increasing this much further by making use of the very low-pressure difference of the battery(below 25 Pascal),low pressure fans and the ventilation system as a whole.展开更多
文摘An energy-saving control strategy based on predictive control for central air-conditioning systems is proposed in this paper. The cold load model is developed to describe the dynamic characteristics of temperature control systems, and then parameters in the cold load model and in the central air-conditioning system model are estimated. Generalized predictive control (GPC) is used to establish an optimization model to minimize the consumption of energy and the control error of temperature. The simulated annealing (SA) algorithm, combined with quadratic programming, is adopted to solve the optimal problem. Contrasted with the simulation of traditional PID control, the results prove the effectiveness of this proposed strategy.
文摘Septic shock is a common critical condition, for which effective early fluid resuscitation is the therapeutic focus. According to the 2008 international guidelines for management of severe sepsis and septic shock, resuscitation should achieve a central venous pressure （CVP） of 8-12 mmHg within the first 6 h. However, it is still uncertain about the sensitivity and specificity of CVP in reflecting the cardiac preload. Ultrasonography is a simple, rapid, non-invasive, and repeatable method for the measurement of sensitivity and specificity of CVP and has thus gradually attracted the increasing attention of physicians. It was reported that ultrasonography can show the inferior vena cava diameter, respiratory variability index, and blood volume in patients with sepsis or heart failure.
基金Partly supported by a Grant-in-Aid for Scientific Research(C),No.26507010a grant to the Respiratory Failure Research Group from Ministry of Health,Labor and Welfare,Japan
文摘Adaptive servo-ventilation(ASV) has been developed as a specific treatment for sleep-disordered breathing, in particular Cheyne-Stokes respiration with central sleep apnea(CSA). Heart failure patients often have sleep-disordered breathing, which consists of either obstructive sleep apnea(OSA) or CSA. Other medical conditions, such as stroke, acromegaly, renal failure, and opioid use may be associated with CSA. Continuous positive airway pressure(CPAP) therapy is widely used for patients with OSA, but some of these patients develop CSA on CPAP, which is called treatmentemergent CSA. CPAP can be useful as a treatment for these various forms of CSA, but it is insufficient to eliminate respiratory events in approximately half of patients with CSA. As compared to CPAP, ASV may be a better option to treat CSA, with sufficient alleviation of respiratory events as well as improvement of cardiac function in heart failure patients. In patients without heart failure, ASV can also alleviate CSA and relieve their symptom. Recently, ASV has been widely used for patients with various forms of CSA. ASV may be also used in the setting without CSA, but it should be assessed more carefully. Clinicians should have a better understanding of the indications for ASV in each setting.
文摘The systemic administration of morphine affects ventilation via a mixture of central and peripheral actions. The aims of this study were to characterize the ventilatory responses elicited by a low dose of morphine in conscious rats;to determine whether tolerance develops to these responses;and to determine the potential roles of peripheral μ-opioid receptors (μ-ORs) in these responses. Ventilatory parameters were monitored via unrestrained whole-body plethysmography. Conscious male Sprague-Dawley rats received an intravenous injection of vehicle or the peripherally-restricted μ-OR antagonist, naloxone methiodide (NLXmi), and then three successive injections of morphine (1 mg/kg) given 30 min apart. The first injection of morphine in vehicle-treated rats elicited an array of ventilatory excitant (i.e., increases in frequency of breathing, minute volume, respiratory drive, peak inspiratory and expiratory flows, accompanied by decreases in inspiratory time and end inspiratory pause) and inhibitory (i.e., a decrease in tidal volume and an increase in expiratory time) responses. Subsequent injections of morphine elicited progressively and substantially smaller responses. The pattern of ventilatory responses elicited by the first injection of morphine was substantially affected by pretreatment with NLXmi whereas NLXmi minimally affected the development of tolerance to these responses. Low-dose morphine elicits an array of ventilatory excitant and depressant effects in conscious rats that are subject to the development of tolerance. Many of these initial actions of morphine appear to involve activation of peripheral μ-ORs whereas the development of tolerance to these responses does not.
文摘Heart failure (HF) is known to be associated with sleep-disordered breathing(SDB). In addition to disturbing patients’ sleep, SDB is also associated with a deterioration in the cardiac function and an increased mortality and morbidity.Central sleep apnea (CSA), typically characterized by Cheyne-Stokes breathing(CSB), is increasingly found in patients with HF compared to the general population. An important pathogenetic factor of CSA seen in HF patients is an instability in the control of the respiratory system, characterized by both hypocapnia and increased chemosensitivity. Sympathetic overactivation,pulmonary congestion and increased chemosensitivity associated with HF stimulate the pulmonary vagal irritant receptor, resulting in chronic hyperventilation and hypocapnia. Additionally, the repetitive apnea and arousal cycles induce cyclic sympathetic activation, which may worsen the cardiac prognosis. Correcting CSB may improve both patient’s quality of life and HF syndrome itself. However, a treatment for HF in patients also experiencing CSA is yet to be found. In fact, conflicting results from numerous clinical studies investigating sleep apnea with HF guide to a troubling question, that is whether(or not) sleep apnea should be treated in patients with HF? This editorial attempts to both collect the current evidence about randomized control trials investigating CSA in patients with HF and highlight the effect of specific CSA treatments on cardiovascular endpoints.
基金The project is financed via a public grant of the Rijksdienst Voor Ondernemend Nederland(RVO,https://www.rvo.nl/)within the Urban Energy 2018 Research-Line with Grant No.TEUE318008.The grant is awarded to the following consortium:The Delft University of Technology(https://www.tudelft.nl/en),Van Dorp B.V.,Hunter Douglas Europe B.V.(https://www.hunterdouglasarchitectural.eu/),Priva B.V.(https://www.priva.com/nl)and the Green Village Foundation(https://www.thegreenvillage.org/en/).
文摘This research evaluates the performance of a Phase Change Material(PCM)battery integrated into the climate system of a new transparent meeting center.The main research questions are:a.“Can the performance of the battery be calculated?”and b.“Can the battery reduce the heating and cooling energy demand in a significant way?”The first question is answered in this document.In order to be able to answer the second question,especially the way the heat loading in winter should be improved,then more research is necessary.In addition to the thermal battery,which consists of Phase Change Material plates,the climate system has a cross-flow heat exchanger and a heat pump.The battery should play a central role in closing the thermal balance of the lightweight building,which can be loaded with hot return or cold outdoor air.The temperature of the battery plates is monitored by multi-sensors and simulated by the use of PHOENICS(Computational Fluid Dynamics)and MATLAB.This paper reports reasonable agreement between the numerical predictions and the measurements,with a maximum variance of 10%.The current coefficient of performance for heating and cooling is already high,more than 27.There is scope for increasing this much further by making use of the very low-pressure difference of the battery(below 25 Pascal),low pressure fans and the ventilation system as a whole.
