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Modeling the effects of stretch-dependent surfactant secretion on lung recruitment during variable ventilation

journal of Biomedical Science and Engineering 2013年第12期6卷 61-70页

作者： Samir D. Amin Arnab Majumdar Phil Alkana allan j. walkey George T. O’Connor Béla Suki Department of Biomedical Engineering Boston University Boston USA School of Medicine Boston University Boston USA

Variable ventilation (VV) is a novel strategy of ventilatory support that utilizes random variations in the delivered tidal volume (VT) to improve lung function. Since the stretch pattern during VV has been shown to increase surfactant release both in animals and cell culture, we hypothesized that there were combinations of PEEP and VT during VV that led to improved alveolar recruitment compared to conventional mechanical ventilation (CV). To test this hypothesis, we developed a computational model of stretch-induced surfactant release combined with abnormal alveolar mechanics of the injured lung under mechanical ventilation. We modeled the lung as a set of distinct acini with independent surfactant secretion and thus pressure-volume relationships. The rate of surfactant secretion was modulated by the stretch magnitude that an alveolus experienced per breath. Mechanical ventilation was simulated by delivering a prescribed VT at each breath. The fractional VT that each acinus received depended on its local compliance relative to the total system compliance. Regional variability in VT thus developed through feedback between stretch and surfactant release and coupling of regional VT to ventilator settings. The model allowed us to simulate patient-ventilator interactions over a wide range of PEEPs and VTs during CV and VV. Full recruitment was achieved through VV at a lower PEEP than required for CV. During VV, the acini were maintained under non-equilibrium steady-state conditions with breath-by-breath fluctuations of regional VT. In CV, alveolar injury was prevented with high-PEEP-low-VT or low-PEEP-high-VT combinations. In contrast, one contiguous region of PEEP-VT combinations allowed for full recruitment without overdistention during VV. We found that maintaining epithelial cell stretch above a critical threshold with either PEEP or VT may help stabilize the injured lung. These results demonstrate the significance of patient-ventilator coupling through the influenc

关键词： Computational Modeling Mechanical Ventilation Variable Ventilation Surfactant Secretion Dynamics

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Association of latitude and altitude with adverse outcomes in patients with COVID-19: The VIRUS registry

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World journal of Critical Care Medicine 2022年第2期11卷 102-111页

作者： Aysun Tekin Shahraz Qamar Romil Singh Vikas Bansal Mayank Sharma Allison M LeMahieu Andrew C Hanson Phillip j Schulte Marija Bogojevic Neha Deo Simon Zec Diana j Valencia Morales Katherine A Belden Smith F Heavner Margit Kaufman Sreekanth Cheruku Valerie C Danesh Valerie M Banner-Goodspeed Catherine A St Hill Amy B Christie Syed A Khan Lynn Retford Karen Boman Vishakha KKumar john C O'Horo juan Pablo Domecq allan j walkey Ognjen Gajic Rahul Kashyap Salim Surani TheSociety of Critical Care Medicine(SCCM)Discovery Viral Infection and Respiratory Illness Universal Study(VIRUS):COVID-Registry Investigator Group Department of Anesthesiology Mayo ClinicRochesterMN 55905United States Post-baccalaureate Research Education Program Mayo Clinic College of Medicine and ScienceRochesterMN 55905United States Division of Pulmonary and Critical Care Medicine Department of Internal MedicineMayo ClinicRochesterMN 55905United States Division of Clinical Trials and Biostatistics Department of Quantitative Health SciencesMayo ClinicRochesterMN 55905United States Alix School of Medicine Mayo ClinicRochesterMN 55905United States Division of Infectious Diseases Thomas Jefferson University HospitalPhiladelphiaPA 19107United States Prisma Health GreenvilleSC 29605United States Englewood Health EnglewoodNJ 07631United States Divisions of Cardiothoracic Anesthesiology and Critical Care Medicine Department of Anesthesiology and Pain ManagementUT Southwestern Medical CenterDallasTX 75390United States Center for Applied Health Research Baylor Scott and White HealthDallasTX 75246United States Department of Anesthesiology Critical Care and Pain MedicineBeth Israel Deaconess Medical CenterBostonMA 02215United States Allina Health MinneapolisMN 55407United States Department of Critical Care Atrium Health NavicentMaconGA 31201United States Division of Critical Care Medicine Mayo Clinic Health SystemMankatoMN 56001United States Society of Critical Care Medicine Mount ProspectIL 60056United States Division of Infectious Diseases Mayo ClinicRochesterMN 55905United States Division of Nephrology and Hypertension Department of Internal MedicineMayo ClinicRochesterMN 55905United States Pulmonary Center Division of PulmonaryAllergyCritical Care and Sleep MedicineDepartment of MedicineEvans Center of Implementation and Improvement SciencesBoston University School of MedicineBostonMA 02118United States Department of Pulmonary and Critical Care Medicine Texas A&M UniversityBryanTX 77807United States 不详

BACKGROUND The coronavirus disease 2019(COVID-19)course may be affected by environmental *** studies previously suggested a link between climatological factors and COVID-19 fatality ***,individual-level impact of these factors has not been thoroughly evaluated *** To study the association of climatological factors related to patient location with unfavorable outcomes in *** In this observational analysis of the Society of Critical Care Medicine Discovery Viral Infection and Respiratory Illness Universal Study:COVID-19 Registry cohort,the latitudes and altitudes of hospitals were examined as a covariate for mortality within 28 d of admission and the length of hospital *** for baseline parameters and admission date,multivariable regression modeling was *** estimating equations were used to fit the *** Twenty-two thousand one hundred eight patients from over 20 countries were *** median age was 62(interquartile range:49-74)years,and 54%of the included patients were *** median age increased with increasing latitude as well as the frequency of ***,the percentage of comorbidities was lower in elevated *** within 28 d of hospital admission was found to be 25%.The median hospital-free days among all included patients was 20 *** the significant linear relationship between mortality and hospital-free days(adjusted odds ratio(aOR)=1.39(1.04,1.86),P=0.025 for mortality within 28 d of admission;aOR=-1.47(-2.60,-0.33),P=0.011 for hospital-free days),suggesting that adverse patient outcomes were more common in locations further away from the Equator;the results were no longer significant when adjusted for baseline differences(aOR=1.32(1.00,1.74),P=0.051 for 28-day mortality;aOR=-1.07(-2.13,-0.01),P=0.050 for hospital-free days).When we looked at the altitude’s effect,we discovered that it demonstrated a non-linear association with mortality wi

关键词： 28 d mortality Altitude COVID-19 Hospital-free days Latitude Outcomes

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白菜、甘蓝品种对芜菁花叶病毒的抗病性

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上海农业学报 1987年第1期 23-30页

作者：丁辛顺 D.G.A.walkey C.j.Bolland 上海市农业科学院园艺研究所 Institute of Horticultural Research Wellesbourne Warwick UK Institute of Horticultural Research Wellesbourne Warwick UK 上海

本试验在温室和尼龙网室内测定了27份白菜(Brassica Chinensis和BrassicaPekinensis)和甘蓝品种,对来源于中国上海、英国及西德的三个芜青花叶病毒株系的抗病性。结果发现白菜与甘蓝品种的症状反应范围均可由轻微至严重。不同的白菜品... 详细信息

本试验在温室和尼龙网室内测定了27份白菜(Brassica Chinensis和BrassicaPekinensis)和甘蓝品种,对来源于中国上海、英国及西德的三个芜青花叶病毒株系的抗病性。结果发现白菜与甘蓝品种的症状反应范围均可由轻微至严重。不同的白菜品种对上述三个株系的感病性存在较大的差异,其中有些品种对英国和西德的二个株系比较抗病,但对中国的株系则比较感病。品种“japro”对三个株系均表现较高的抗病性,甘蓝品种一般对中国的株系比较抗病,品种“寒光”对三个株系表现出较强的抗性或耐病性。在网室栽培试验中,感病植株与健康植株相比,产量下降7.3—94.7％。受不同株系侵染后,产量下降幅度有所变化,症状严重程度与产量下降百分率之间存在明显的相关性。

关键词：青菜大白菜甘蓝抗病性芜菁花叶病毒

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脱毒大蒜苗的生产与检测技术

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上海农业学报 1988年第1期 23-28页

作者：丁辛顺上海市农业科学院园艺研究所上海

免疫电镜(ISEM)检测结果表明,从北也门萨那(Sana’a)地区引进的大蒜鳞茎中带有洋葱黄矮病毒和另外二种未知的病毒。本试验对这些受病毒侵染的大蒜鳞茎进行了热处理和茎尖分生组织培养,并从中获得了一批健康的幼苗。本项试验结果表明,大... 详细信息

免疫电镜(ISEM)检测结果表明,从北也门萨那(Sana’a)地区引进的大蒜鳞茎中带有洋葱黄矮病毒和另外二种未知的病毒。本试验对这些受病毒侵染的大蒜鳞茎进行了热处理和茎尖分生组织培养,并从中获得了一批健康的幼苗。本项试验结果表明,大蒜的茎尖分生组织在Gamborg’s B5矿物盐培养基上生长良好。在进行组织培养之前,如能置大蒜苗于36℃和38℃下热处理四周,可比不经热处理的大蒜鳞茎产生更多的健康苗。

关键词：大蒜组织培养免疫电镜

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苹果新梢的组织培养:五个品种对细胞激动素和生长素的反应比较

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北方果树 1984年第1期 35-36页

作者： W.D.Lane j.M.Mcdougald 王际轩

苹果新梢的无菌培养,报道最早的是 Elliott(1972)and walkey(1972)。随之,很多品种培养成功,并发展了离体培养繁殖程序。高的新梢增殖速度和生根频率对大规模繁殖和获得更多砧木和接穗品种是有益的(jones 等1977,1979;Lane 1978)。使用... 详细信息

苹果新梢的无菌培养,报道最早的是 Elliott(1972)and walkey(1972)。随之,很多品种培养成功,并发展了离体培养繁殖程序。高的新梢增殖速度和生根频率对大规模繁殖和获得更多砧木和接穗品种是有益的(jones 等1977,1979;Lane 1978)。使用的培养基则因报道的实验室和培养的品种而不同。在以往的所有报道中,我们尚未发现为了新梢增殖(细胞激动素)和生根启动(生长素),对不同品种苹果新梢培养体所必需的生长调节剂的浓度范围比较

关键词：新梢细胞激动素生长素反应

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