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Diagnostic value of digital continuous bowel sounds in critically ill patients with acute gastrointestinal injury: A prospective observational study
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作者 Yuan-Hui Sun yun-yun song +5 位作者 Sha Sha Qi Sun Deng-Chao Huang Lan Gao Hao Li Qin-Dong Shi 《World Journal of Gastrointestinal Surgery》 SCIE 2024年第12期3818-3834,共17页
BACKGROUND Acute gastrointestinal injury(AGI)is common in intensive care unit(ICU)and worsens the prognosis of critically ill patients.The four-point grading system proposed by the European Society of Intensive Care M... BACKGROUND Acute gastrointestinal injury(AGI)is common in intensive care unit(ICU)and worsens the prognosis of critically ill patients.The four-point grading system proposed by the European Society of Intensive Care Medicine is subjective and lacks specificity.Therefore,a more objective method is required to evaluate and determine the grade of gastrointestinal dysfunction in this patient population.Digital continuous monitoring of bowel sounds and some biomarkers can change in gastrointestinal injuries.We aimed to develop a model of AGI using continuous monitoring of bowel sounds and biomarkers.AIM To develop a model to discriminate AGI by monitoring bowel sounds and biomarker indicators.METHODS We conducted a prospective observational study with 75 patients in an ICU of a tertiary-care hospital to create a diagnostic model for AGI.We recorded their bowel sounds,assessed AGI grading,collected clinical data,and measured biomarkers.We evaluated the model using misjudgment probability and leave-one-out cross-validation.RESULTS Mean bowel sound rate and citrulline level are independent risk factors for AGI.Gastrin was identified as a risk factor for the severity of AGI.Other factors that correlated with AGI include mean bowel sound rate,amplitude,interval time,Sequential Organ Failure Assessment score,Acute Physiology and Chronic Health Evaluation II score,platelet count,total protein level,blood gas potential of hydrogen(pH),and bicarbonate(HCO3-)level.Two discriminant models were constructed with a misclassification probability of<0.1.Leave-one-out cross-validation correctly classified 69.8%of the cases.CONCLUSION Our AGI diagnostic model represents a potentially effective approach for clinical AGI grading and holds promise as an objective diagnostic standard for AGI. 展开更多
关键词 Critical illness Acute gastrointestinal injury Bowel sounds Biomarker Intensive care unit Citrulline Gastrin Diagnostic value
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单茂钪催化月桂烯与丁二烯共聚合的研究 被引量:2
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作者 付洪然 宋芸芸 +1 位作者 任晓瑞 郭方 《高分子学报》 SCIE CAS CSCD 北大核心 2018年第11期1416-1421,共6页
采用(C_5Me_4SiMe_3)Sc(CH_2SiMe_3)_2(THF)(1)、Cp′Sc(CH_2C_6H_4NMe_(2-)o)2(2:Cp′=C5Me4SiMe3;3:Cp′=C5H5)3种单茂钪催化剂,考察了其催化月桂烯均聚合以及与丁二烯共聚合的性能,并对所获聚合物的微观结构和热性能进行了分析.结果... 采用(C_5Me_4SiMe_3)Sc(CH_2SiMe_3)_2(THF)(1)、Cp′Sc(CH_2C_6H_4NMe_(2-)o)2(2:Cp′=C5Me4SiMe3;3:Cp′=C5H5)3种单茂钪催化剂,考察了其催化月桂烯均聚合以及与丁二烯共聚合的性能,并对所获聚合物的微观结构和热性能进行了分析.结果表明,单茂钪的配体结构直接影响月桂烯聚合的选择性和分子量.配体空间位阻较大的单茂钪1和2催化月桂烯均聚合的活性和选择性相当,获得以3,4-结构为主(61%~74%)的聚月桂烯.配体空间位阻较小的单茂钪3催化月桂烯均聚合的催化活性高达10~5 g polymer mol Sc^(-1) h^(-1),获得以cis-1,4-结构为主(95%)的聚月桂烯,聚月桂烯的玻璃化温度为-70°C.采用单茂钪3改变其与月桂烯的比例可实现对聚月桂烯分子量的有效调控(Mn=7.0×10~4~2.31×10~5).单茂钪3也可以催化月桂烯和丁二烯共聚合,5 min内两单体的转化率均达100%,获得与加料组成一致的月桂烯-丁二烯无规共聚物,共聚合活性高达10~5 g polymer mol S_c^(-1) h^(-1).在本文实验范围内设计获得了月桂烯含量范围为19 mol%~75 mol%、Mn在1.02×10~5~2.32×10~5、分子量分布在1.38~1.84的月桂烯-丁二烯无规共聚物,共聚物中两单体的1,4-选择性均大于92%.所获不同组成的月桂烯-丁二烯共聚物只有一个玻璃化转变温度.共聚物中月桂烯的含量由19 mol%的增加到75 mol%,共聚物的玻璃化转变温度从-95°C增加到-71°C. 展开更多
关键词 月桂烯 丁二烯 共聚合
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单茂钪催化月桂烯与苯乙烯共聚合的研究 被引量:1
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作者 刘薇 宋芸芸 +1 位作者 刁凯颖 郭方 《高分子学报》 SCIE CAS CSCD 北大核心 2019年第9期957-963,I0004,共8页
采用(C5H5)Sc(CH2SiMe3)2(THF)(1)、(C5Me4SiMe3)Sc(CH2SiMe3)2(THF)(2)2种单茂钪催化剂,分别考察了其催化月桂烯与苯乙烯共聚合的性能,并通过核磁共振(1H-NMR、13C-NMR)、凝胶渗透色谱(GPC)和示差扫描量热法(DSC)对所获共聚物结构和热... 采用(C5H5)Sc(CH2SiMe3)2(THF)(1)、(C5Me4SiMe3)Sc(CH2SiMe3)2(THF)(2)2种单茂钪催化剂,分别考察了其催化月桂烯与苯乙烯共聚合的性能,并通过核磁共振(1H-NMR、13C-NMR)、凝胶渗透色谱(GPC)和示差扫描量热法(DSC)对所获共聚物结构和热性能进行表征分析.结果表明,在室温甲苯溶剂中,改变月桂烯和苯乙烯的用量,2种单茂钪催化剂均对月桂烯和苯乙烯共聚合表现了较高的催化活性(10^4 g polymer molSc^–1 h^–1),获得了组成可控(月桂烯含量22 mol%~83 mol%)、高分子量(Mn=4.8×10^4~1.13×10^5)、窄分布(Mw/Mn=1.49~1.99)的苯乙烯-月桂烯共聚物,催化剂结构直接影响共聚物的立体和序列结构.采用单茂钪1催化月桂烯与苯乙烯共聚合,月桂烯先聚合形成高顺式1,4-聚月桂烯嵌段(选择性95%),之后苯乙烯开始聚合形成无规聚苯乙烯嵌段,所获共聚物为高顺式聚月桂烯-无规聚苯乙烯嵌段共聚物.由单茂钪1获得的月桂烯-苯乙烯嵌段共聚物均含有–63和96℃2个玻璃化转变温度(Tg),分别对应高顺式聚月桂烯嵌段和无规聚苯乙烯嵌段的Tg.采用单茂钪2催化月桂烯与苯乙烯共聚合,也是月桂烯优先聚合,随后苯乙烯大量聚合,共聚物中月桂烯的含量呈梯度下降趋势而苯乙烯含量呈梯度上升趋势,共聚物为月桂烯-苯乙烯梯度共聚物,共聚物中月桂烯含有3,4-结构单元(选择性75%)和顺式-1,4-结构单元(选择性25%).由单茂钪2获得的月桂烯-苯乙烯梯度共聚物均含有一个–35℃的Tg和一个254℃的熔点(Tm),分别对应聚月桂烯嵌段的Tg和间规聚苯乙烯嵌段的Tm. 展开更多
关键词 单茂钪 月桂烯 苯乙烯 共聚合
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