Enhancement of physicochemical properties and baking quality of broken rice flour through superheated steam

This study investigated the effects of superheated steam(SS)treatment at different temperatures(120℃,150℃,180℃)on the physicochemical properties of broken rice flour and the quality of broken rice cakes.SS treatment at 120℃ significantly enhanced the moisture content of broken rice flour(P<0.05).In contrast,treatments at 150℃ and 180℃ caused decrease of moisture content,amylose leaching,and reduction of damaged starch content.After SS treatment,the pasting properties of broken rice flour increased,along with the rising of storage modulus and loss modulus.The proportion of short chains(DP 6-12)in amylopectin increased from 29.42%to 34.80%(P<0.05),which could delay starch retrogradation.Compared with untreated ones,the SS-150 broken rice cakes showed a significantly higher specific volume(2.96 mL/g,P<0.05),more uniform cell structure,and lower hardness(1.66 N)and chewiness(10.22 mJ).After 7 days of storage,cakes from SS-treated rice flour(150℃ and 180℃)had significantly reduced hardness and chewiness.The study demonstrated that SS treatment could improve the properties of broken rice flour and enhance the quality of broken rice cakes,especially at 150℃ and 180℃.This study presents a method for improving the quality of broken rice flour and rice cakes using superheated steam treatment,addressing challenges related to poor flour characteristics and suboptimal cake quality.The findings offer technical and theoretical support for enhancing rice cake production,contributing to the comprehensive utilization of rice resources.

MicroRNA changes of bone marrow-derived mesenchymal stem cells differentiated into neuronal-like cells by Schwann cell-conditioned medium

Bone marrow-derived mesenchymal stem cells differentiate into neurons under the induction of Schwann cells. However, key microRNAs and related pathways for differentiation remain unclear. This study screened and identified differentially expressed microRNAs in bone marrow- derived mesenchymal stem cells induced by Schwann cell-conditioned medium, and explored targets and related pathways involved in their differentiation into neuronal-like cells. Primary bone marrow-derived mesenchymal stem cells were isolated from femoral and tibial bones, while primary Schwann cells were isolated from bilateral saphenous nerves. Bone marrow-derived mesenchymal stem cells were cultured in unconditioned (control group) and Schwann cell-conditioned medium (bone marrow-derived mesenchymal stem cell + Schwann cell group). Neuronal differentiation of bone marrow-derived mesenchymal stem cells induced by Schwann cell-conditioned medium was observed by time-lapse imaging. Upon induction, the morphology of bone marrow-derived mesencaymal stem cells changed into a neural shape with neurites. Results of quantitative reverse transcription-polymerase chain reaction revealed that nestin mRNA expression was upregulated from 1 to 3 days and downregulated from 3 to 7 days in the bone marrow-derived mesenchymal stem cell + Schwann cell group. Compared with the control group, microtubule-associated protein 2 mRNA expression gradually increased from 1 to 7 days in the bone marrow-derived mesenchymal stem cell + Schwann cell group. After 7 days of induction, microRNA analysis iden:ified 83 significantly differentially expressed microRNAs between the two groups. Gene Ontology analysis indicated enrichment of microRNA target genes for neuronal projection development, regulation of axonogenesis, and positive regulation of cell proliferation. Kyoto Encyclopedia of Genes and Genomes pathway analysis demonstrated that Hippo, Wnt, transforming growth factor-beta, and Hedgehog signaling pathv/ays were potentially associated with neural differentiation of bone marrow-derived mesenchymal stem cells. This study, which carried out successful microRNA analysis of neuronal-like cells differentiated from bone marrow-derived mesenchymal stem cells by Schwann cell induction, revealed key microRNAs and pathways involved in neural differentiation of bone marrow-derived mesenchymal stem cells. All protocols were approved by the Animal Ethics Committee of Institute of Radiation Medicine, Chinese Academy of Medical Sciences on March 12, 2017 (approval number: DWLI-20170311).

贸易强国建设:评估、测度与实施路径

改革开放以来,中国把握经济全球化机遇,逐步从贸易弱小国家成长为世界第一贸易大国,但“大而不强”仍是亟待破解的重要课题。文章梳理了2009年、2015年贸易强国评估工作,开展了2023年贸易强国测度评价,对标美国、德国、日本等贸易强国,评析了我国贸易强国建设取得的重要阶段性进展及存在的差距。针对当前国际贸易发展形势,文章重点研究分析了全球贸易治理受困、全球价值链重构加速、全球供应链危机显现、数字贸易领域分歧明显、绿色低碳经贸规则博弈等六大趋势性问题。在此基础上,提出了加快建设贸易强国的路径与主攻方向,要进一步扩大高水平对外开放,夯实贸易强国的两大支柱和两大新动力,加强统筹协调和保障工作,完善贸易强国评价指标体系和常态化评估。

Human umbilical cord mesenchymal stem cell-derived exosomes loaded into a composite conduit promote functional recovery after peripheral nerve injury in rats

Complete transverse injury of peripheral nerves is challenging to treat.Exosomes secreted by human umbilical cord mesenchymal stem cells are considered to play an important role in intercellular communication and regulate tissue regeneration.In previous studies,a collagen/hyaluronic acid sponge was shown to provide a suitable regeneration environment for Schwann cell proliferation and to promote axonal regeneration.This three-dimensional(3D)composite conduit contains a collagen/hyaluronic acid inner sponge enclosed in an electrospun hollow poly(lactic-co-glycolic acid)tube.However,whether there is a synergy between the 3D composite conduit and exosomes in the repair of peripheral nerve injury remains unknown.In this study,we tested a comprehensive strategy for repairing long-gap(10 mm)peripheral nerve injury that combined the 3D composite conduit with human umbilical cord mesenchymal stem cell-derived exosomes.Repair effectiveness was evaluated by sciatic functional index,sciatic nerve compound muscle action potential recording,recovery of muscle mass,measuring the cross-sectional area of the muscle fiber,Masson trichrome staining,and transmission electron microscopy of the regenerated nerve in rats.The results showed that transplantation of the 3D composite conduit loaded with human umbilical cord mesenchymal stem cell-derived exosomes promoted peripheral nerve regeneration and restoration of motor function,similar to autograft transplantation.More CD31-positive endothelial cells were observed in the regenerated nerve after transplantation of the loaded conduit than after transplantation of the conduit without exosomes,which may have contributed to the observed increase in axon regeneration and distal nerve reconnection.Therefore,the use of a 3D composite conduit loaded with human umbilical cord mesenchymal stem cell-derived exosomes represents a promising cell-free therapeutic option for the treatment of peripheral nerve injury.

新型三维组合式发射线圈的设计与实验

多维无线电力传输是胃肠道胶囊机器人发展的关键。为了解决新型胶囊机器人功能不断增加,而传统三维接收线圈占用内部空间过大的问题,本文提出了一种三维组合式发射线圈,能够通过调制通过各维线圈的电流来产生动态的三维磁场。本文首先介绍了无线供能系统的工作原理,然后对发射系统产生的空间磁场进行了有限元分析。最后利用搭建的实验平台进行实验,验证了仿真结果的准确性并确定了接收线圈感应最大接受电压的姿态。试验结果表明,当发射系统在中心点处产生相等的三维磁场分量时,负载接收能量超过630 mW。此外,发射系统附近边缘区域的位置稳定性超过80%,确保胶囊机器人能够平稳的运行。

新式茶饮标签信息现状分析与标准探索

近年来,新式茶饮行业快速扩张,其创新性和市场活力吸引了大批消费者。消费者在面临丰富多样的茶饮选择时,对产品质量、原材料来源及营养健康信息等方面的关注度也越来越高。然而作为产品质量、成分来源及营养信息的关键披露方式,标签信息的相关研究当前并不完善。本文通过实地走访、线上访谈及问卷发放等方式进行市场调研,并运用扎根理论三级编码分析所得数据,发现当前许多新式茶饮门店在标签信息披露方面存在着信息透明度低、内容不合理、标签不清晰不规范等问题。对此团队提出运用标准化手段在新式茶饮标签信息布局、信息溯源、分级标识制度建立等方面提出对策和建议。

饕餮纹的分类问题

饕餮纹的分类是对其展开系统研究的基础,目前学界的分类主要基于“类型学”和“风格学”。类型学角度的分类常以角或尾等局部特征作为分类标准;风格学角度的分类以罗越的“五种风格说”为代表。前者重视局部,导致分类标准不统一,型式分析所应体现的发展序列不清楚。后者存在单线发展观,类别划分不完善,演进过程模糊等问题。因此,可将风格学和类型学结合起来,前者用于整体性分类,以保证各类形式特征的一致性;后者用于类别内部演进过程的讨论,体现发展脉络。基于此,文中将饕餮纹分为九类,并概述了各类的核心特征和相互间的影响关系。

汉中地区天麻品种筛选试验

为了筛选出适宜汉中山区种植的天麻品种,收集了7个不同的天麻品种开展比较试验。结果表明,品种3(乌红杂交)、品种4(野生红麻驯化)这两个品种产量高、品质好、无烂麻,符合国家药典要求,适宜在汉中山区种植。

不同年龄室间隔缺损修补术患儿麻醉诱导期间不同潮气末二氧化碳分压对局部脑氧饱和度和血流动力学的影响

目的探讨不同年龄室间隔缺损(VSD)修补术患儿麻醉诱导期间不同潮气末二氧化碳分压(P_(ET)CO_2)对局部脑氧饱和度(rScO_2)和血流动力学的影响。方法选取2017年4-5月于首都医科大学附属北京安贞医院行择期VSD修补术患儿44例,按年龄分为≥6个月组(24例)和<6个月组(20例)。入室全身麻醉气管插管后,建立桡动脉血压监测并使用MostCare血流动力学监测仪,使用Fore-Sight连续监测右侧额部rScO_2。调整机械通气参数,分别使P_(ET)CO_2依次维持在30(P_1)、35(P_2)、40(P_3)、45(P_4)mmHg(1 mmHg=0.133 kPa)状态。记录P_1、P_2、P_3、P_4状态时rScO_2、心率、收缩压、重脉压与舒张压的差值、每搏指数、心排血指数、体循环阻力指数、脉压变异度。结果随P_(ET)CO_2升高,2组rScO_2均明显升高[<6个月组P_1、P_2、P_3、P_4状态时rScO_2分别为(65±3)%、(69±3)%、(74±3)%、(77±4)%;≥6个月组P_1、P_2、P_3、P_4状态时rScO_2分别为(71±6)%、(74±6)%、(78±5)%、(80±4.)%](均P<0.001);随P_(ET)CO_2变化,<6个月组rScO_2变化幅度大于≥6个月组(P=0.011)。随P_(ET)CO_2升高,≥6个月组收缩压、心排血指数、脉压变异度下降,<6个月组体循环阻力指数下降,≥6个月组和<6个月组心率均先下降后上升(均P<0.05)。≥6个月组收缩压高于<6个月组(P=0.024),其余参数组间比较差异均无统计学意义(均P>0.05)。结论 VSD患儿在麻醉诱导阶段,随着P_(ET)CO_2变化脑氧合和血流动力学变化反应良好,年龄较小患儿因脑血管功能储备有限,脑氧合受P_(ET)CO_2波动的影响更大。

高活菌数益生菌发酵乳联合肠内营养在颅脑损伤术后患者中的效果观察

目的探讨高活菌数益生菌发酵乳联合肠内营养在颅脑损伤术后患者中的疗效。方法选取2015年4月至2016年3月新疆维吾尔自治区人民医院神经外科监护室(NICU)收治的重症颅脑损伤患者80例,依据随机数字表法分为观察组(高活菌数益生菌发酵乳联合肠内营养支持,43例)和对照组(单纯肠内营养支持,37例)。2组患者术后24 h开始启动肠内营养,观察组每日肠内营养开始0.5 h前,经鼻饲管给予益生菌活菌发酵乳200 ml,4次/d。4周后观察2组患者感染发生情况、抗生素使用频度、感染持续时间,比较2组患者肠内营养支持过程中胃肠道功能情况、达到目标能量需要的时间及NICU的入住时间。结果观察组总体感染和肺部感染发生率均低于对照组[51.2%(22/43)比86.5%(32/37),30.2%(13/43)比56.8%(21/37)](均P<0.05);观察组患者感染持续时间低于对照组,抗生素使用频度低于对照组(均P<0.05);观察组患者在肠内营养支持过程中腹泻、腹胀等胃肠道并发症的发生率均低于对照组[14.0%(6/43)比32.4%(12/37),7.0%(3/43)比27.0%(10/37)],达到肠内营养目标供给量所需的平均时间及转出NICU进入普通病房的时间短于对照组(均P<0.05)。结论增加高活菌数益生菌发酵乳的肠内营养支持方法有助于改善颅脑损伤术后患者的肠道微生态环境,防止细菌移位,能更有效预防和减少感染性并发症的发生,对调节患者术后胃肠道动力、缩短个体达到目标能量及转出NICU的时间有积极作用。

七氟醚对室间隔缺损患儿脑血管CO2反应性的影响

目的使用经颅多普勒超声监测脑血流,比较静脉麻醉药与七氟醚对室间隔缺损患儿脑血管二氧化碳反应性(cerebrovascular carbon dioxide reactivity,CO2R)的影响。方法纳入3~12月龄患儿32例,随机分为两组。静脉组静注哌库溴铵0.2 mg/kg、咪达唑仑0.2 mg/kg及舒芬太尼1 μg/kg,肌松满意后行气管插管,全凭静脉维持麻醉。吸入组持续吸入七氟醚1.5 MAC,静注哌库溴铵0.2 mg/kg,自主呼吸消失后行气管插管,七氟醚1.0 MAC维持麻醉。调整机械通气条件,使PETCO2依次维持在30 mmHg(T1)、35 mmHg(T2)、40 mmHg(T3)、45 mmHg(T4),使用经颅多普勒超声测量右侧大脑中动脉血流平均速度(VMCA),同时记录HR、心脏指数(CI)及BIS,计算CO2R。结果T1—T4时两组VMCA明显增加,HR明显减慢(P<0.01);吸入组BIS值和CO2R明显下降(P<0.01或P<0.05)。与静脉组比较,吸入组T3和T4时VMCA,T1—T4时HR、T1—T2时段CO2R明显增高(P<0.01或P<0.05)。结论1.0 MAC七氟醚麻醉下,在低PETCO2范围内CO2R更高,且高于使用静脉麻醉药物。

草原典型牧草的特征提取与识别研究

选择四种内蒙古乌兰察布市荒漠化草原的典型牧草,对牧草图像进行颜色、形状特征提取,以实现牧草的分类识别,为提高牧草管理信息化水平,实现多牧草种类分割识别及牧草盖度、频度等检测研究奠定基础。在自然光照情况下应用高清照相机采集尺寸、形状、大小各不相同的草原原始牧草图像,对羊草(Leymus chinensis)、鹅绒委陵菜(Potentilla anserine)、阿尔泰狗娃花(Heteropappus altaicus),冷蒿(Artemisia frigida)四种牧草图像提取9种RGB颜色一、二、三阶矩特征与6种宽长比等形状特征,统计获取相应的数据库,试验表明颜色矩、形状特征参数具有显著的差异。构建一种3层BP(Back propagation,BP)神经网络模型,应用主成分分析法(principal component analysis,PCA)优选特征明显的维数,降低计算成本、提升识别效率,四种牧草平均识别率为82.5%,上述试验证明该方法能够有效地对内蒙古草原典型牧草图像进行分类识别研究。牧草自动识别技术的发展为草业管理信息化提供数据支撑,是实现现代生态草原的重要途径。

发绀型先天性心脏病改良体-肺动脉分流术中血流动力学变化

目的:使用压力记录分析法(PRAM)监测发绀型先天性心脏病患儿改良体-肺动脉(m BT)分流术中血流动力学的变化,分析其临床应用价值,并以此作为选择容量治疗或强心治疗的依据。方法:选择28例择期行m BT分流术的先天性心脏病患儿,主要诊断法洛四联症19例,肺动脉狭窄+室间隔缺损6例,肺动脉闭锁+室间隔缺损3例,月龄2~24个月,中位月龄10.6(6.2,18.9)个月,体质量(10.5±5.1)kg,Nakata指数平均(125±41)mm^2/m^2。在切皮前(T0)、切心包1 min(T1)、部分阻断肺动脉1 min和10 min(T2、T3)、部分阻主动脉后(T4)、人工血管开放通血1 min和10 min(T5、T6)、术毕(T7),记录循环周期效率(CCE)、心排血指数(CI)、心每搏指数(SVI)、收缩压(SBP)、重脉压与舒张压差值(Pdic-a)、压力升支最大斜率(dp/dt_(max))、体循环阻力指数(SVRI)、脉压变异度(PPV)。结果:各时间点dp/dt_(max)的平均值均>1.0 mm Hg/ms(1mm Hg=0.133k Pa)。人工血管通血前(T0-T4),T3点CCE、CI、SVI均处于最低点,其中CCE_(T3)明显低于CCE_(T0-T1)(P均<0.05),CI_(T3)明显低于CI_(T0-T2)(P均<0.01),SVI_(T3)明显低于SVI_(T0-T2)(P<0.01,P<0.01和P<0.05);Pdic-a_(T4)处于最低点,显著低于Pdic-a_(T0-1)(P<0.01和P<0.05);SVRI_(T3)处于最高点,明显高于SVRI_(T0)(P<0.01)。人工血管通血后(T5-T7),T5点CCE、CI、SVI、Pdic-a均处于最低点,其中CCE_(T5)明显低于CCE_(T7)(P<0.05),CI_(T5)明显低于CI_(T6-T7)(P均<0.05),SVI_(T5)明显低于SVI_(T6-T7)(P均<0.05),Pdic-aT5明显低于Pdic-aT6-7(P<0.01);PPVT5明显高于PPVT6-T7(P<0.01)。在T6和T7点,PPV与Pdic-a呈显著负相关(r=-0.51,r=-0.53,P均<0.01)。结论:m BT术中血流动力学维护重点,在人工血管通血前以强心为主,应用正性肌力药维护心功能,在人工血管通血后通过扩容维护有效循环血容量。通过CCE、CI、SVI、dp/dt_(max)、PPV、Pdic-a等血流动力学监测指标,精准判断液体治疗和应用正性肌力药治疗的权重,从而积极防治患儿术中低氧血症,稳定血流动力学状态。

基于改进VGGNet的羊个体疼痛识别方法

针对目前人工识别羊个体疼痛过程中存在的经验要求高、识别准确率低、消耗成本高、延误疾病治疗等问题,引入当前主流图像分类网络VGGNet(Visual geometry group network)对有疼痛和无疼痛的羊脸表情进行识别,提出一种基于改进VGGNet的羊脸痛苦表情识别算法,改进后的网络为STVGGNet(Spatial transformer visual geometry group network)。该算法将空间变换网络引入VGGNet,通过空间变换网络增强对羊脸痛苦表情特征区域的关注程度,提高对羊脸痛苦表情的识别准确率。本文对原有的羊脸表情数据集进行了扩充,新增887幅羊脸表情图像。但是新的数据集图像数量仍然较少,所以本文利用ImageNet数据集进行迁移学习,微调后用来自动分类有痛苦和无痛苦的羊脸表情。对羊面部表情数据集的实验结果表明,使用STVGGNet实现的最佳训练准确率为99.95%,最佳验证准确率为96.06%,分别比VGGNet高0.15、0.99个百分点。因此,本文采用的模型在羊脸痛苦表情识别中有非常好的识别效果并且具有较强的鲁棒性,为畜牧业中羊的疾病检测智能化发展提供了技术支撑。

Discussion on New Evaluation Technology of Non-Metallic Composite Continuous Pipe for Oil and Gas Field

In view of the serious lack and lag of the test and evaluation technology of non-metallic composite continuous pipe, and focusing on the characteristics of the application of non-metallic composite continuous pipe in oil field, this paper discusses a series of new full-scale test and evaluation technologies for accurately evaluating the product quality and practical application performance of non-metallic composite continuous pipe, which effectively solves the major technical problem that the new products of non-metallic pipe cannot be accurately evaluated. Based on the characteristics of the application of non-metallic composite continuous pipe in oil field, a series of new full-scale test evaluation technologies which can accurately evaluate the product quality and practical application performance of non-metallic pipe are designed through a large number of tests. The test and evaluation technology can accurately evaluate the key performance of high and low pressure cycle, high and low temperature cycle, gas permeability resistance, minimum bending radius etc. It provides a scientific evaluation basis for the standardized application of non-metallic continuous pipe and a reliable quality control method for the selection of products in oil field.

用压力记录分析法分析完全肺静脉异位引流患儿手术中血流动力学变化

目的:采用压力记录分析技术(PRAM)研究完全肺静脉异位引流(TAPVC)患儿的围术期血流动力学变化。方法:本研究共纳入了在全麻下行完全性肺静脉异位引流(TAPVC)矫治手术的患儿42例,入室后常规麻醉诱导,气管插管后行桡动脉或股动脉穿刺置管连续监测动脉血压,并连接Mostcare-PRAM监测仪。在全麻诱导结束手术开始前(T1),切开心包肝素化前(T2)、拔除主动脉插管后(T3)和术毕离室前(T4)各个时间点采集心率(HR)、收缩压(Sys P)、舒张压(Dia P)、重脉压(Dic P)、体循环阻力(SVR)、每搏量指数(SVI)、心指数(CI)、每搏量变异度(SVV)、心脏循环效率(CCE)和最大压力梯度(dp/dt)血流动力学参数。结果:CCE中T3比T1、T2均显著降低(P<0.01),T4比T3均显著增高(P<0.01);HR中T2、T3、T4比T1均显著增高(P<0.01),T3、T4比T2均显著增高(P<0.01);SVR中T3比T1、T2均显著增高(P<0.01),T4比T1、T2均显著增高(P<0.05);SVI中T3、T4比T1均显著降低(P<0.05);SVV中T2比T1显著降低(P<0.05),T3比T2显著增高(P<0.01);DPDT中T3比T1、T2均显著增高(P<0.05),T4比T1、T2均显著增高(P<0.01),T4比T3显著增高(P<0.05)。CI各个时间点之间不存在显著差异。结论:TAPVC患儿围术期易发左心衰,因此应进行严格的容量控制。应用PRAM法监测,量化反映术中前后负荷和心脏收缩功能的变化规律,能够为畸形矫治前后血管活性药物的选择和容量治疗等提供依据。

脉压变异度和每搏量变异度在室间隔缺损患儿术中预测容量反应的探讨

目的探讨右侧小切口室间隔缺损修补术患儿在开胸状态下,脉压变异度(PPV)和每搏量变异度(SVV)是否可以预测容量反应,以及二者的准确性的差异。方法 56例年龄(1.2±1.0)岁,体重(8.7±2.0) kg行室间隔缺损修补术的患儿,在体外循环结束后,机械通气条件为吸入氧浓度50%,潮气量10 ml/kg,呼吸频率16～25次/min,使PETCO2维持在30～35 mm Hg。拔出主动脉插管之后进行容量负荷试验,以30 ml/(kg·h)速度输注5%白蛋白或血浆15 min。记录容量负荷试验前、后PPV和SVV,同时记录心率(HR)、收缩压(SBP)、舒张压(DBP)、每搏指数(SVI)、心指数(CI)、压力升支最大速率(dp/dtmax)、体循环阻力指数(SVRI)。根据容量负荷试验后CI的变化将所有患儿分为两个组,CI增加≥15%为有反应组,否则为无反应组。绘制受试者特征曲线(ROC)比较PPV、SVV预测容量反应准确性。结果有反应组患儿共27例,无反应组患儿共29例。容量负荷试验前有反应组PPV、SVV明显高于无反应组,均P <0.01。ROC分析以PPV和SVV预测容量反应的准确性分别为0.89和0.78。PPV的诊断阈值为18%,敏感性为83%,特异性为81%; SVV的诊断阈值为18. 5%,敏感性为83%,特异性为62%。容量负荷试验前有反应组SBP、DBP、CI(均P <0.01)、SVI(P <0.05)明显低于无反应组。容量负荷试验后有反应组SBP、DBP、SVI、CI、dp/dtmax均明显上升(均P <0.01),SBP、CI高于无反应组(P <0.05)。容量负荷试验前PPV和SVV均与ΔSBP(P <0.0001)、ΔDBP(P <0.05)、ΔCI(P <0.0001)、ΔSVI(P <0.0001)呈正相关,与ΔSVRI呈负相关(P <0.05)。结论在室间隔缺损患儿修补术中,容量管理对于维护血流动力学稳定十分重要。开胸状态下,PPV、SVV能够预测容量反应及指导容量管理,且PPV更准确。

室间隔缺损修补手术中脑氧饱和度及脑血流速度和血流动力学变化及其相互关系

目的探讨室间隔缺损修补手术中脑氧饱和度(rSc0_2)、脑血流速度、血流动力学的变化及其相互关系。方法纳入2017年5—9月在首都医科大学附属安贞医院行室间隔缺损修补手术患儿18例,年龄(0.59±0.19)岁,体质量(6.4±1.6)kg。术中采用静脉复合麻醉,持续应用舒芬太尼2～4μg/(kg·h)、咪达唑仑0.2～0.4mg/(kg.h)、哌库溴铵80～160μg/(kg·h)。采用Fore-Sight近红外光谱仪监测额部rScO_2,经颅多普勒探测颞窗大脑中动脉血流速度,Mostcare(压力记录分析法)监测血流动力学。分别记录切皮前(T_1)、切心包时(T_2)、停体外循环时(T_3)、改良超滤后10 min(T_4)、术毕(T_5)的rScO_2、收缩期峰值脑血流速度(Vs)、舒张期峰值脑血流速度(Vd)、平均脑血流速度(Vm)、脑搏动指数(PI)、脑阻抗指数(RI)、收缩压、舒张压、重脉压、外周血管阻力指数(SVRI)、心率、每搏量指数(SVI)、心指数、动脉压力升支最大斜率(dp/dtmax)、脉压变异度(PPV)、潮气末二氧化碳分压(P_(ET)CO_2)。结果 T_2时Vm、收缩压、SVR1、dp/dtmax明显高于T_1时;T_3时rScO_2、Vd、舒张压、重脉压、SVI、心指数、P_(ET)CO_2明显低于,PI和RI明显高于T_1、T_2、T_4、T_5时;T_5时Vs、Vm、SVRI、心率、PPV明显低于T_4时,差异均有统计学意义(均P<0.05)。相关性分析结论如下:T_1时,Vs与年龄,Vm与重脉压呈明显正相关(r=0.485、0.493,均P<0.05)。T_2时,Vs、Vm与年龄,Vs与rScO_2呈明显正相关(r=0.464、0.467、0.550,均P<0.05)。T_3时,Vs、Vm与rScO_2呈明显正相关(r=0.695、0.526,均P<0.05)。T_4时,Vm、Vd与年龄呈明显正相关(r=0.566、0.577,均P<0.01);Vs、Vd、Vm与PPV呈明显负相关(r=-0.661、-0,488、-0.659,均P<0.05)。T_5时,Vm、Vd与年龄,rScO_2与dp/dtmax呈明显正相关(r=0.453、0.625、0.592、0.489,均P<0.05)。结论在室间隔修补手术中,脑血流速度与年龄、血流动力学关系密切。建立体外循环阶段和体外循环结束时脑血流速度对rScO_2有明显影响。改良超滤能明显增加脑血流速度,降低脑血管阻力,同时rScO_2明显升高。

门静脉高压患儿围术期血流动力学的变化

目的通过压力记录分析法(PRAM)分析门静脉高压(PH)患儿围术期动脉后负荷、心功能、容量负荷参数的一般变化特点,为临床医师提供参考。方法纳入2017年1-12月本院择期行肠-门静脉(改良)分流手术的PH患儿共20例(PH组),年龄<14岁,ASAⅡ或Ⅲ级。随机选取同期年龄匹配行开腹手术患儿20例作为对照组(非PH组)。在麻醉诱导后,常规行桡动脉置管以监测血压和使用PRAM。在切皮前(T1)、切皮5 min后(T2)、关腹(T3)、术毕时(T4)使用PRAM记录SBP、DBP、HR、重脉压、每搏量指数(SVI)、心脏指数(CI)、心室弹性(Ees)、动脉后负荷(Ea)、脉压变异度(PPV);记录麻醉时间、麻醉药物用量。结果与非PH组比较,T1-T4时PH组HR明显减慢(P<0.05),T3-T4时重脉压明显增高(P<0.05),T1、T2、T4时SVI明显增高(P<0.05),T1、T2、T4时Ea明显降低(P<0.05),T2、T3时PPV明显降低(P<0.05),T3、T4时Ees明显降低(P<0.05)。两组间SBP、DBP与CI差异无统计学意义。结论PH患儿围术期血流动力学变化特点为每搏量增高和动脉后负荷降低,心功能轻微受损,脉压变异度数值偏低。

Synthesis of Organic Modified SiC_w/PVDF Composite Membrane and Its Dielectric Properties under Low Temperature

Cetyltrimethylammonium bromide(CTAB) was incorporated into silicon carbide whiskers(SiCw) to improve their hydrophobicity. The solution casting method was employed to develop composite membranes of polyvinylidene fluoride(CTAB-SiCw/PVDF) with different feed ratios. FT-IR spectroscopic studies proved that CTAB was successfully incorporated into the SiCw. SiCw phase structure was maintained after modification by CTAB according to XRD results. SEM studies indicated that the surface became smoother with CTAB dispersal in the PVDF membrane. The dielectric properties of the composite membranes containing various amounts of CTAB-SiCw were measured at low temperature. It was found that the dielectric constant of the composite membranes with 13.0 wt% whiskers reached a maximum value of 25 at low frequency, and decreased to nine at high frequency(from 500 Hz to 1 MHz) at 0 ℃. The dielectric loss of each composite membrane increased with increasing temperature and reached a maximum value. The value shifted with corresponding frequency increases. In addition, the dielectric loss reached a maximum value of 0.2 when 16.7 wt% of CTAB-SiCw was fed at each frequency(from-30 ℃ to 10 ℃). At room temperature, the dielectric constant could be maintained at 42 and the loss factor decreased to 0.8 at 100 Hz when 13.0 wt% of CTABSiCw was incorporated. Additionally, TGA experiments indicated that the decomposition temperature of a PVDF membrane was increased by 10 ℃ and its heat resistance was improved by adding 13.0 wt% of CTAB-SiCw. This PVDF composite membrane has potential for use as an insulator and capacitor.