舒适化浅镇静策略对ICU机械通气病人的影响

目的:观察舒适化浅镇静(eCASH)策略对重症监护室(ICU)机械通气病人的影响。方法:将医院2018年1月—2021年10月收治的在ICU行机械通气治疗的150例病人纳入研究,以随机数字表法分为观察组、对照组各75例,入住ICU后对照组给予常规镇静镇痛护理,观察组在此基础上给予eCASH策略护理干预,干预后观察两组治疗效果、不良事件发生率、镇痛镇静药物用量、氧化应激反应及转归情况。结果:观察组病人机械通气时间及ICU住院时间均短于对照组,唤醒时间早于对照组(P<0.05);观察组病人谵妄发生率为4.00%,低于对照组的13.33%(P<0.05),呼吸机相关肺炎发生率为6.67%,低于对照组的17.33%(P<0.05),意外拔管发生率为4.00%,低于对照组的14.67%(P<0.05);观察组镇痛镇静药物用量少于对照组(P<0.05);干预后观察组病人超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-PX)水平高于对照组,血清丙二醛(MDA)水平低于对照组(P<0.05);观察组转科率为98.67%,高于对照组的90.67%(P<0....     

Effect of Bi,Sb, and Ti on Microstructure and Mechanical Properties of SAC105 Alloys

The Sn-Ag-Cu (SAC) solder alloys with a low Ag (Ag < 3 wt.%) content have attracted great attention owing to their low cost, increased ability in bulk compliance, and plastic energy dissipation. However, some of their mechanical properties are generally lower than the SAC alloys with a higher Ag content. Adding alloying elements is an effective approach for improving the mechanical properties of the SAC alloys. In this study, the effect of Bi, Sb, and Ti on Sn-1 wt.%Ag-0.5 wt.%Cu (SAC105) solder alloys was investigated. The SAC solders with four compositions: SAC105-1 wt.%Bi, SAC105-1 wt.%Sb, SAC105-1 wt.%Bi-1 wt.%Sb, SAC105-1 wt.%Bi-1 wt.%Sb-0.4 wt.%Ti were prepared. The microstructure and phase compositions were characterized using electron scanning microscopy, and X-ray diffraction. The thermal properties and wettability were also examined. Uniaxial tensile tests and nano-indentation tests were conducted to evaluate the mechanical properties. The results show that adding Bi or Sb could increase the strength of SAC105 alloys mainly due to the solid solution strengthening effect. The creep resistance of SAC105 alloys was also improved with the additions of Bi and Sb. The co-additions of Bi and Sb into SAC105 alloys exhibit an enhanced creep resistance than that calculated by the theoretical calculation. The further addition of Ti into SAC105-1Bi-1Sb alloys demonstrated a much-improved creep resistance, which could be attributed to the synergistic effects of both solid solution strengthening and the precipitation hardening effects.     

Selected Physical and Spectroscopic Properties of TPS Moldings Enriched with Durum Wheat Bran

The impact of the amount of durum wheat bran additive used on the selected structural, mechanical, and spectroscopic properties of thermoplastic starch moldings was examined in this study. Bran was added to corn starch from 10 to 60% by weight in the blends. Four temperature settings were used for the high-pressure injection: 120, 140, 160, and 180 °C. The highest value of elongation at break (8.53%) was observed for moldings containing 60% bran. Moreover, for these moldings, the tensile strength and flexural strength were lower (appropriately 3.43 MPa and 27.14 MPa). The highest deformation at break (1.56%) were obtained for samples with 60% bran and injection molded at 180 °C. We saw that higher bran content (50 and 60%) and a higher injection molding temperature (160 °C and 180 °C) significantly changed the color of the samples. The most significant changes in the FTIR spectra were observed at 3292 and 1644 cm⁻¹ and in the region of 1460–1240 cm⁻¹. Moreover, notable changes were observed in the intensity ratio of bands at 1015 and 955 cm⁻¹. The changes observed correspond well with the amount of additive used and with the injection temperature applied; thus it may be considered as a marker of interactions affecting plasticization of the material obtained.     

酪氨酸蛋白激酶抑制剂对大鼠呼吸机所致肺损伤的保护作用

目的研究酪氨酸蛋白激酶抑制剂金雀异黄素(genistein)对大鼠呼吸机所致肺损伤(VILI)的保护作用。方法30只健康SD大鼠随机均分成A、B、C3组,A组为正常潮气量机械通气组:潮气量(VT)=8ml·kg-1;B组为大潮气量机械通气组:潮气量(VT)=40ml·kg-1;C组为大潮气量通气加Genistein处理组:潮气量(VT)=40ml·kg-1,C组大鼠实验前30min腹腔注射Genistein溶液(50mg·kg-1)。A、B、C3组机械通气频率(P)均为每分钟80次,通气时间均为2h。实验完毕收集肺组织和肺灌洗液标本。光镜观察肺病理改变,TUNEL法检测肺组织细胞凋亡情况,同时测定肺灌洗液中总蛋白、肺湿/干比、白细胞计数、肿瘤坏死因子(TNF-α)等指标以及肺组织中中性粒细胞髓过氧化物酶(MPO)的水平。结果和A组相比,B组肺病理改变明显,肺细胞凋亡数量增加,肺湿/干比、总蛋白、白细胞计数、MPO、TNF-α等指标均增高(P<0.01);和B组比较,C组肺病理改变明显减轻,肺细胞凋亡数量减少,肺湿/干比、总蛋白、白细胞计数、MPO、TNF-α等指标均降低(P<0.05)。结论酪氨酸蛋白激酶抑制剂genistein对大鼠呼吸机所致的肺损伤具有较好的保护作用。     

有创-无创序贯性机械通气救治慢性阻塞性肺疾病合并严重呼吸衰竭的疗效观察

目的 探讨有创-无创序贯性机械通气在慢性阻塞性肺疾病(COPD)合并严重Ⅱ型呼吸衰竭治疗中的方法与疗效.方法 分析呼吸内科重症监护室(RICU)40例COPD合并严重Ⅱ型呼吸衰竭、分别接受有创-无创序贯性机械通气治疗(序贯组)与传统气管插管机械通气治疗(对照组)患者的病例资料,观察两组患者病情变化、血气分析结果、发生呼吸机相关肺炎(VAP)例数、死亡例数、有创和总机械通气时间、再插管率及住院时间.结果 序贯组与对照组治疗前的血气分析结果相仿(P＞0.05);发生VAP分别为1例和6例(P＜0.05),死亡分别为1例和2例(P＞0.05),有创机械通气时间分别为(5.9±2.2)d和(14.1±3.6)d(P＜0.01),总机械通气时间分别为(12.2±6.2)d和(14.1±3.6)d(P＜0.05),再插管例数分别为1例和2例(P＞0.05),住院时间分别为(15±7)d和(19±4)d(P＜0.05).再插管率和死亡率两组之间比较无差异.结论 对于COPD合并严重Ⅱ型呼吸衰竭的患者,以“肺部感染控制窗”为切换点,实施有创-无创序贯性机械通气,可降低VAP发生率,缩短机械通气时间和住院时间,是救活COPD合并严重Ⅱ型呼吸衰竭值得提倡的机械通气策略.     

重症肺炎患者机械通气排气管路细菌学特征分析

目的:研究重症细菌性肺炎机械通气患者下呼吸道分泌物、呼吸机呼气管道冷凝水和呼吸机排出气的细菌学特征。方法:对74例重症细菌性肺炎患者在机械通气治疗24h时分别采集下呼吸道分泌物、呼吸机排气管冷凝水、呼吸机排出气的标本,进行半定量细菌培养。结果:74例下呼吸道分泌物中细菌培养阳性64例;呼气管冷凝水细菌培养阳性51例,与其下呼吸道分泌物培养结果的符合率为96.08%(49/51);呼吸机排气口气体细菌培养阳性35例,与下呼吸道分泌物培养结果的符合率为91.43%(32/35),与冷凝水培养结果的符合率为97.14%(34/35)。结论:重症肺炎应适当缩短呼吸机管道更换间隔(24h);致病菌由呼吸道→呼吸机管路→呼吸机排出气的传播路径不容忽视;机械通气患者呼气管冷凝水细菌培养结果对呼吸道病原学诊断具有借鉴意义。     

增塑剂及膜材比例对Eudragit L100/S100游离膜机械性能和透湿性的影响

采用平面铸膜法制备对pH敏感、可用于结肠定位的Eudragit L100/S100游离膜,并考察成膜湿度、增塑剂的种类与用量及膜材的比例对游离膜的影响。以膜的透湿性、机械性能为指标设计正交实验,优选出最佳的成膜处方,并研究其相关特性。结果表明,以柠檬酸三乙酯为增塑剂且含量为30%时,膜的机械性能和成膜性最好;膜材比例变化对游离膜的机械性能和透湿性影响不大。通过调整增塑剂的种类、用量及Eudragit L100/S100配比,可以制得符合结肠定位释放要求的游离膜。     

Analysis of The Working Performance of Large Curvature Prestressed Concrete Box Girder Bridges

Based on numerical shape functions and the structural stressing state theory, the mechanical properties of the curved prestressed concrete box girder (CPCBG) bridge model under different loading cases are presented. First, the generalized strain energy density (GSED) obtained from the measured strain data is used to represent the stressing state pattern of the structure; then, the stressing state of the concrete section is analyzed by plotting the strain and stress fields of the bridge model. The stressing state pattern and strain fields of the CPCBG are shown to reveal its mechanical properties. In addition, the measured concrete strain data are interpolated by the non-sample point interpolation (NPI) method. The strain and stress fields of the bridge model have been plotted to analyze the stressing state of the concrete cross-section. The internal forces in the concrete sections are calculated by using interpolated strains. Finally, the torsional effects are simulated by measuring the displacements to show the torsional behavior of the cross-section. The analysis and comparison of the internal force and strain fields reveal the common and different mechanical properties of the bridge model. The results of the analysis of the curved bridge model provide a reference for the future rational design of bridge projects.     

Microstructure and Mechanical Properties of Metal Foams Fabricated via Melt Foaming and Powder Metallurgy Technique: A Review

Metal foams possess remarkable properties, such as lightweight, high compressive strength, lower specific weight, high stiffness, and high energy absorption. These properties make them highly desirable for many engineering applications, including lightweight materials, energy-absorption devices for aerospace and automotive industries, etc. For such potential applications, it is essential to understand the mechanical behaviour of these foams. Producing metal foams is a highly challenging task due to the coexistence of solid, liquid, and gaseous phases at different temperatures. Although numerous techniques are available for producing metal foams, fabricating foamed metal still suffers from imperfections and inconsistencies. Thus, a good understanding of various processing techniques and properties of the resulting foams is essential to improve the foam quality. This review discussed the types of metal foams available in the market and their properties, providing an overview of the production techniques involved and the contribution of metal foams to various applications. This review also discussed the challenges in foam fabrications and proposed several solutions to address these problems.     

Correlation of Bone Material Model Using Voxel Mesh and Parametric Optimization

The authors present an algorithm for determining the stiffness of the bone tissue for individual ranges of bone density. The paper begins with the preparation and appropriate mechanical processing of samples from the bovine femur and their imaging using computed tomography and then processing DICOM files in the MIMICS system. During the processing of DICOM files, particular emphasis was placed on defining basic planes along the sides of the samples, which improved the representation of sample geometry in the models. The MIMICS system transformed DICOM images into voxel models from which the whole bone FE model was built in the next step. A single voxel represents the averaged density of the real sample in a very small finite volume. In the numerical model, it is represented by the HEX8 element, which is a cube. All voxels were divided into groups that were assigned average equivalent densities. Then, the previously prepared samples were loaded to failure in a three-point bending test. The force waveforms as a function of the deflection of samples were obtained, based on which the global stiffness of the entire sample was determined. To determine the stiffness of each averaged voxel density value, the authors used advanced optimization analyses, during which numerical analyses were carried out simultaneously, independently mapping six experimental tests. Ultimately, the use of genetic algorithms made it possible to select a set of stiffness parameters for which the error of mapping the global stiffness for all samples was the smallest. The discrepancies obtained were less than 5%, which the authors considered satisfactory by the authors for such a heterogeneous medium and for samples collected from different parts of the bone. Finally, the determined data were validated for the sample that was not involved in the correlation of material parameters. The stiffness was 7% lower than in the experimental test.