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A Neural Circuit Mechanism Controlling Breathing by Leptin in the Nucleus Tractus Solitarii

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Neuroscience Bulletin 2022年第2期38卷 149-165页

作者： Hongxiao Yu Luo Shi Jinting Chen Shirui Jun Yinchao Hao Shuang Wang Congrui Fu Xiang Zhang Haiyan Lu Sheng Wang Fang Yuan Department of Physiology Hebei Medical UniversityShijiazhuang 050017HebeiChina Core Facilities and Centers Institute of Medicine and HealthHebei Medical UniversityShijiazhuang 050017HebeiChina School of Nursing Hebei Medical UniversityShijiazhuang 050000HebeiChina Department of Orthodontics College of StomatologyHebei Medical UniversityShijiazhuang 050017HebeiChina Hebei Key Laboratory of Neurophysiology Shiji azhuang 050017HebeiChina

Leptin,an adipocyte-derived peptide hormone,has been shown to facilitate breathing.However,the central sites and circuit mechanisms underlying the respiratory effects of leptin remain incompletely understood.The present study aimed to address whether neurons expressing leptin receptor b(LepRb)in the nucleus tractus solitarii(NTS)contribute to respiratory control.Both chemogenetic and optogenetic stimulation of LepRb-ex-pressing NTS(NTS^(LepRb))neurons notably activated breathing.Moreover,stimulation of NTS^(LepRb) neurons projecting to the lateral parabrachial nucleus(LPBN)not only remarkably increased basal ventilation to a level similar to that of the stimulation of all NTS^(LepRb) neurons,but also activated LPBN neurons projecting to the preBotzinger complex(preBotC).By contrast,ablation of NTS^pRb neurons projecting to the LPBN notably eliminated the enhanced respiratory effect induced by NTSLepRb neuron stimulation.In brainstem slices,bath application of leptin rapidly depolarized the membrane potential,increased the spontaneous firing rate,and accelerated the Ca2+transients in most NTSLepRb neurons.Therefore,leptin potentiates breathing in the NTS most likely via an NTS-LPBN-preBdtC circuit.

关键词： Leptin ventilation Nucleus tractus solitarii Neural circuit Chemogenetics

Steady-state model for predicting size-resolved gas-particle partitioning of semi-volatile organic compounds (SVOCs) in indoor environments

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Building Simulation 2023年第3期16卷 443-460页

作者： Jianping Cao Yu Han Yujie Zhu Xingyu Duan Luyang Wang Haibao Huang School of Environmental Science and Engineering Sun Yat-sen UniversityGuangzhou 510006China Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology Guangzhou 510006China Department of Building Science Tsinghua UniversityBeijing 100084China

Semi-volatile organic compounds(SVOCs)are ubiquitous and important pollutants in indoor environments.The strong partition between gas phase and suspended particles has significant effects on the transport,human exposure via inhalation,and control strategies of indoor SVOCs.Several models have been developed to simulate the gas–particle partitioning of indoor SVOCs,including a steady-state model by expanding the steady-state model suitable for the outdoor environment to indoor environments.However,the effects of two important indoor environment-specific parameters,i.e.,the particle size distribution(PSD)and the air-change rate(ACH),were not considered in the existing steady-state model,leading to the inaccurate predictions among buildings.To solve this problem,this study developed a novel steady-state model to more comprehensively simulate the gas-particle partitioning of indoor SVOCs by incorporating the effects of PSD and ACH.Better agreement between the predictions of the novel model and the results collected via both field tests and laboratory tests(retrieved from two different studies)supported the effectiveness of the improvements in the novel model.Sensitivity analysis further supported the necessity of involving PSD and ACH.Further implications of the novel model were also discussed.This study should be helpful for deepening the understanding and accurate simulation of the gas-particle partitioning,as well as the transport and human exposure via inhalation,of indoor SVOCs.

关键词： indoor air quality airborne particles particle size distribution ventilation mass transfer analysis

Numerical study on formation of a splash sheet induced by an oscillating bubble in extreme vicinity to a water surface

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Journal of Hydrodynamics 2022年第6期34卷 1021-1031页

作者： Guang-hang Wang Yan Du Zhi-jian Xiao Jian Huang Zhi-ying Wang Hong-chen Li Jing-zhu Wang Yi-wei Wang Key Laboratory for Mechanics in Fluid Solid Coupling Systems Institute of MechanicsChinese Academy of SciencesBeijing100190China School of Future Technology University of the Chinese Academy of SciencesBeijing100049China School of Engineering Science University of the Chinese Academy of SciencesBeijing100049China Department of Biomedical Engineering ThoraxcenterErasmus MC University Medical Center RotterdamRotterdamThe Netherlands

When it is generated in extreme vicinity to a water surface,an oscillating bubble bursts into the atmosphere and high-pressure gas is simultaneously exhausted from it,forming a splash sheet and an open cavity.The dynamics of the splash sheet induced by the bursting of the oscillating bubble has drawn increasing attention,but it is not clearly understood.We conduct a numerical simulation in the framework of open-source software OpenFOAM.The volume of fluid and Reynolds-Averaged Navier-Stokes methods are used to precisely capture the gas-liquid interface and obtain flow structure,respectively.In addition,an experimental setup is carried out based on an object distance compensation method for validation of the numerical model.Two patterns are summarized:(1)An open splash,(2)A sealed splash depending on whether a splash sheet completely closes.Detailed numerical results shows that the bubble bursting is induced by the Rayleigh-Taylor instability.Finally,the splash closures are discussed for two patterns.

关键词： Cavitation bubble ventilation splash sheet flow patterns Rayleigh-Taylor instability

ventilation and Relative Humidity in Swedish Buildings

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Journal of Environmental Protection 2014年第11期5卷 1022-1036页

作者： Thomas Alsmo Catharina Alsmo Library Research Olten Switzerland

An important factor for comfort ratio in the indoor environment and affecting human health and well-being is the relative humidity. Studies have shown that about 70% of the staff at Swedish offices, schools and kindergartens experiences that the air is too dry during the winter season. Studies show that the relative humidity in indoor environments influences the incidence of respiratory infections and allergies. Important factors for the air environment indoors is to limit the number of airborne particles, since these are conveyors of both bacteria and viruses, and to keep the humidity at a level above 40% and below 70%, making the survival of viruses and bacteria minimized. Measurement results show that there is significant difference in the relative humidity during the winter season between the mechanically ventilated buildings with relative humidity levels below 10% than in buildings with natural ventilation. An important issue is how human health is affected by during longer periods and during much of the day live in environments with low relative humidity. Several researchers have noted that the incidence of respiratory infections increase during the winter when people are exposed to long periods of low humidity indoors. This means that the consequences of low humidity in the indoor environment should be considered and evaluated in a completely different way than is done today.

关键词： Indoor Air Humidity ventilation Hygiene and Health Air Quality Sick Building Syndrome (SBS) Indoor Environment Indoor Temperature

Simulation Analysis of Ammonia Leakage and Dispersion in a Large-Scale Refrigeration System

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Fluid Dynamics & Materials Processing 2022年第4期18卷 1049-1066页

作者： Jianlu Cheng Kaiyong Hu Jiang Shen Lu Jia Rui Niu Zhaoxian Yang Tianjin Key Laboratory of Refrigeration Technology Tianjin University of CommerceTianjin300134China International Trade Engineering Design Institute Beijing100037China Tianjin Tengsheng Technology Co. Ltd.Tianjin300380China

The use of ammonia in large-scale refrigeration systems(such as those used for a stadium)requires adequate ammonia leakage prevention mechanisms are put in place.In the present study,numerical simulations have been conducted to study the dispersion law in the ammonia machinery room of the refrigeration system for the 2022 Beijing Winter Olympics.The wind speed,and release location have been varied to investigate their effects on the dispersion profile.Different positions of the leakage points in the ammonia storage tank have been found to lead to different areas affected accordingly.In general,the dangerous region area decreases with an increase in the wind speed.However,when the wind is aligned with the leakage direction,this trend is reverted.The study may offer an effective method to predict the impact of ammonia dispersion and implement the safe operation of such large-scale systems.

关键词： Numerical simulation ammonia diffusion leakage location ventilation

Clinical characteristics and outcomes associated with nasal intermittent mandatory ventilation in acute pediatric respiratory failure

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World Journal of Critical Care Medicine 2018年第4期7卷 46-51页

作者： Billy C Wang Theodore Pei Cheryl B Lin Rong Guo David Elashoff James A Lin Carol Pineda Department of Pediatrics Division of Critical Care MedicineLoma Linda University Children’s Hospital Department of Pediatrics Division of Pediatric Critical CareFloating Hospital for Children at Tufts Department of Medicine Biostatistics CoreUCLA David Geffen School of Medicine Department of Pediatrics Mattel Children’s Hospital at UCLA

AIM To characterize the clinical course and outcomes of nasal intermittent mandatory ventilation(NIMV) use in acute pediatric respiratory failure.METHODS We identified all patients treated with NIMV in the pediatric intensive care unit(PICU) or inpatient general pediatrics between January 2013 and December 2015 at two academic centers.Patients who utilized NIMV with other modes of noninvasive ventilation during the same admission were included.Data included demographics,vital signs on admission and prior to initiation of NIMV,pediatric risk of mortality Ⅲ(PRIsM-Ⅲ) scores,complications,respiratory support characteristics,PICU and hospital length of stays,duration of respiratory support,and complications.Patients who did not require escalation to mechanical ventilation were defined as NIMV responders;those who required escalation to mechanical ventilation(MV) were defined as NIMV nonresponders.NIMV responders were compared to NIMV non-responders.RESULTS Forty-two patients met study criteria.six(14%) failed treatment and required MV.The majority of the patients(74%) had a primary diagnosis of bronchiolitis.The median age of these 42 patients was 4 mo(range 0.5-28.1 mo,IQR 7,P = 0.69).No significant difference was measured in other baseline demographics and vitals on initiation of NIMV;these included age,temperature,respiratory rate,O2 saturation,heart rate,systolic blood pressure,diastolic blood pressure,and PRIsM-Ⅲ scores.The duration of NIMV was shorter in the NIMV nonresponder vs NIMV responder group(6.5 h vs 65 h,P < 0.0005).Otherwise,NIMV failure was not associated with significant differences in PICU length of stay(LOs),hospital LOs,or total duration of respiratory support.No patients had aspiration pneumonia,pneumothorax,or skin breakdown.CONCLUSION Most of our patients responded to NIMV.NIMV failure is not associated with differences in hospital LOs,PICU LOs,or duration of respiratory support.

关键词： Continuous positive airway pressure Pediatric Noninvasive positive pressure ventilation Nasal intermittent mandatory ventilation High flow nasal cannula Acute respiratory failure Bilevel positive airway pressure

Iatrogenic pneumothorax related to mechanical ventilation

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世界重症医学杂志 2014年第1期3卷 8-14页

作者： Chien-Wei Hsu Shu-Fen Sun School of Medicine National Yang-Ming University Intensive Care Unit Department of Medicine Kaohsiung Veterans General Hospital Department of Physical Medicine and Rehabilitation Kaohsiung Veterans General Hospital

Pneumothorax is a potentially lethal complication associated with mechanical ventilation. Most of the patients with pneumothorax from mechanical ventilation have underlying lung diseases; pneumothorax is rare in intubated patients with normal lungs. Tension pneumothorax is more common in ventilated patients with prompt recognition and treatment of pneumothorax being important to minimize morbidity and mortality. Underlying lung diseases are associated with ventilatorrelated pneumothorax with pneumothoraces occurring most commonly during the early phase of mechanical ventilation. The diagnosis of pneumothorax in critical illness is established from the patients' history, physical examination and radiological investigation, although the appearances of a pneumothorax on a supine radiograph may be different from the classic appearance on an erect radiograph. For this reason, ultrasonography is beneficial for excluding the diagnosis of pneumothorax. Respiration-dependent movement of the visceral pleura and lung surface with respect to the parietal pleura and chest wall can be easily visualized with transthoracic sonography given that the presence of air in the pleural space prevents sonographic visualization of visceral pleura movements. Mechanically ventilated patients with a pneumothorax require tube thoracostomy placement because of the high risk of tension pneumothorax. Small-bore catheters are now preferred in the majority of ventilated patients. Furthermore, if there are clinical signs of a tension pneumothorax, emergency needle decompression followed by tube thoracostomy is widely advocated. Patients with pneumothorax related to mechanical ventilation who have tension pneumothorax, a higher acute physiology and chronic health evaluation Ⅱ score or Pa O2/Fi O2 < 200 mm Hg were found to have higher mortality.

关键词： Barotrauma Complication Critical care Mechanical ventilation Pneumothorax

Preemptive mechanical ventilation can block progressive acute lung injury

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World Journal of Critical Care Medicine 2016年第1期5卷 74-82页

作者： Benjamin Sadowitz Sumeet Jain Michaela Kollisch-Singule Joshua Satalin Penny Andrews Nader Habashi Louis A Gatto Gary Nieman the Southeastern Center for Digestive Disorders and Pancreatic Cancer Advanced Minimally Invasive and Robotic Surgery Florida Hospital Tampa Department of Surgery Upstate Medical University Critical Care Medicine Surgical Critical Care Trauma Critical Care Medicine The R Adams Cowley Shock Trauma Center University of Maryland Biological Sciences Department SUNY Cortland

Mortality from acute respiratory distress syndrome(ARDS) remains unacceptable, approaching 45% in certain high-risk patient populations. Treating fulminant ARDS is currently relegated to supportive care measures only. Thus, the best treatment for ARDS may lie with preventing this syndrome from ever occurring. Clinical studies were examined to determine why ARDS has remained resistant to treatment over the past several decades. In addition, both basic science and clinical studies were examined to determine the impact that early, protective mechanical ventilation may have on preventing the development of ARDS in at-risk patients. Fulminant ARDS is highly resistant to both pharmacologic treatment and methods of mechanical ventilation. However, ARDS is a progressive disease with an early treatment window that can be exploited. In particular, protective mechanical ventilation initiated before the onset of lung injury can prevent the progression to ARDS. Airway pressure release ventilation(APRV) is a novel mechanical ventilation strategy for delivering a protective breath that has been shown to block progressive acute lung injury(ALI) and prevent ALI from progressing to ARDS. ARDS mortality currently remains as high as 45% in some studies. As ARDS is a progressive disease, the key to treatment lies with preventing the disease from ever occurring while it remains subclinical. Early protective mechanical ventilation with APRV appears to offer substantial benefit in this regard and may be the prophylactic treatment of choice for preventing ARDS.

关键词： Mechanical ventilation Acute lung injury Acute respiratory distress syndrome Airway pressure release ventilation

Independent lung ventilation: Implementation strategies and review of literature

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World Journal of Critical Care Medicine 2019年第4期8卷 49-58页

作者： Sheri Berg Edward A Bittner Lorenzo Berra Robert M Kacmarek Abraham Sonny Division of Critical Care Department of AnesthesiaCritical Care and Pain MedicineMassachusetts General HospitalBostonMA 02114United States Department of Respiratory Care Massachusetts General HospitalBostonMA 02114United States

Independent lung ventilation,though infrequently used in the critical care setting,has been reported as a rescue strategy for patients in respiratory failure resulting from severe unilateral lung pathology.This involves isolating and ventilating the right and left lung differently,using separate ventilators.Here,we describe our experience with independent lung ventilation in a patient with unilateral diffuse alveolar hemorrhage,who presented with severe hypoxemic respiratory failure despite maximal ventilatory support.Conventional ventilation in this scenario leads to preferential distribution of tidal volume to the nondiseased lung causing over distension and inadvertent volume trauma.Since each lung has a different compliance and respiratory mechanics,instituting separate ventilation strategies to each lung could potentially minimize lung injury.Based on review of literature,we provide a detailed description of indications and procedures for establishing independent lung ventilation,and also provide an algorithm for management and weaning a patient from independent lung ventilation.

关键词： Unilateral lung injury Unilateral pneumonia Double lumen tube Differential lung ventilation Acute lung injury Ventilator induced lung injury