Mechanical Modeling of Tube Bending Considering Elastoplastic Evolution of Tube Cross-Section

Aluminum alloy tubes are widely used in various industries because of their excellent performance. Up to now, when the tube is bent, the elastoplastic deformation evolution mechanism of the cross-section has not been clear, and no direct analytical proof has been found. In this paper, based on the bilinear material model assumption, a new mechanical model of tube plane bending deformation is constructed. The analytical model can describe in detail the evolution mechanism of elastic–plastic deformation on the cross-section of the tube after bending deformation, the position of the elastic–plastic boundary, the position of the radius of the strain neutral layer, and the relationship between the bending moment over the section and the bending radius. According to this model, the deformation law of the tube cross-section during bending is elucidated. The results are as follows: (1) the deformation evolution of the cross-section of the bending deformed tube calculated by the analytical model is in good agreement with the finite element model (FEM) of pure bending. (2) By comparing the results of the analytical model with FEM results, and the processing test of the self-designed four-axis free bending forming tube bender, the bending moments are in good agreement. (3) Compared with the bending moments calculated by several other analytical models of tube bending, this model has a relatively small deviation value.     

Timing of Breastfeeding Initiation Mediates the Association between Delivery Mode,Source of Breastfeeding Education,and Postpartum Depression Symptoms

Background: Emergency cesarean section (EMCS) and breastfeeding difficulties increase the risk of postpartum depressive (PPD) symptoms. Early initiation of breastfeeding (EIBF) may not only alleviate PPD symptoms but also facilitate subsequent breastfeeding success. EMCS is a risk factor for not practicing EIBF. Therefore, it is important to understand the relationship between EMCS, EIBF, and PPD symptoms. Methods: We conducted a prospective cohort study in three areas of China. At baseline, a total of 965 mothers completed electronic questionnaires within 72 h postpartum. Women were screened for PPD symptoms using the Edinburgh Postpartum Depression Scale (EPDS). Multivariate logistic regression was used to identify the determinants of PPD symptoms. Mediation analysis was used to determine if EIBF mediated the relationship between delivery mode or breastfeeding education source and PPD symptoms. Results: The prevalence of EIBF was 40.6%; 14% of 965 mothers experienced EMCS, and 20.4% had PPD symptoms. The risk factors for developing PPD symptoms were excessive gestational weight gain (adjusted odds ratio [aOR] = 1.55, confidence interval [95% CI]: 1.03–2.33, p = 0.037) and EMCS (aOR = 2.05, 95% CI: 1.30–3.25, p = 0.002). The protective factors for developing PPD symptoms were monthly household income over CNY 10000 (aOR = 0.68, 95% CI: 0.47–0.97, p = 0.034), EIBF (aOR = 0.49, 95% CI: 0.34–0.72, p < 0.001), and prenatal breastfeeding education from nurses (aOR = 0.46, 95% CI: 0.29–0.73, p = 0.001). EIBF indirectly affected PPD symptoms in patients who had undergone EMCS (percentage mediated [PM] = 16.69, 95% CI: 7.85–25.25, p < 0.001). The source of breastfeeding education through EIBF also affected PPD symptoms (PM = 17.29, 95% CI: 3.80–30.78, p = 0.012). Conclusion: The association between EMCS on PPD symptoms was mediated by EIBF. By providing breastfeeding education, nurses could also help alleviate PPD symptoms.     

Anaesthetic management of an obstetric patient with Pompe disease

Pompe disease (Glycogen storage disease type II) leads to abnormal glycogen deposition in various vital organs resulting in multiple systemic sequelae. We present the anaesthetic management for caesarean section of a 31-year-old parturient with known Pompe disease. The parturient had symptoms and signs of respiratory dysfunction and the pregnancy was complicated by preeclampsia. She underwent urgent caesarean section under regional anaesthesia resulting in the birth of a healthy baby girl. To our knowledge, this is the first reported case of both spinal anaesthesia for caesarean section and successful live birth in a patient with Pompe disease.     

鞘内注射芬太尼对硬膜外麻醉下剖宫产术中恶心、呕吐的抑制作用

目的观察鞘内注射芬太尼对硬膜外麻醉下剖宫产术中恶心、呕吐发生的抑制作用。方法将硬膜外麻醉下行剖宫术产者30例(ASA分级Ⅰ~Ⅱ级)随机均分为对照组和芬太尼组,比较两组产妇术中出现恶心、呕吐的情况,并对娩出婴儿行Apgar评分。结果对照组与芬太尼组术中发生恶心者分别为5例(33.3%)和1例(6.7%);对照组呕吐或干呕发生率则显著高于芬太尼组(P<0.05);两组娩出婴儿的Apgar评分无显著差异(P>0.05)。结论鞘内注射芬太尼能减少产妇硬膜外麻醉下剖宫产术中恶心、呕吐的发生。     

卡前列甲醛栓防治剖宫产术后出血50例临床分析

目的 探讨研究卡前列甲醛栓在临床剖宫产术后出血患者防治中的应用.方法 选择本院妇产科2009年1月至2010年12月间收治的100例剖宫产患者的临床手术及护理情况进行回顾性分析,患者被随机分为两组并分别予以缩宫素与卡前列甲醛栓治疗,并对两组产后出血的防治效果进行对比.结果 研究组患者术后总出血量为(424±172)ml...     

延续性护理干预对剖宫产患者切口美观性及生活质量的影响

目的 分析延续性护理干预对剖宫产患者切口美观性及生活质量的影响。方法 选取我院2023年 1月-6月收治的100例剖宫产患者为研究对象,采用随机数字表法分为对照组和观察组,各50例。对照组 予以围术期护理干预,观察组在对照组基础上予以延续性护理干预,比较两组切口瘢痕宽度及厚度、 切口美观度、术后生活质量、母乳喂养情况及乳房肿胀程度。结果 观察组瘢痕宽度及厚度低于对照 组（P ＜0.05）;观察组切口美观率高于对照组（P ＜0.05）;观察组术后社会关系、环境、心理健康、 生理健康评分高于对照组（P ＜0.05）;观察组纯母乳喂养占比高于对照组（P ＜0.05）;观察组乳房肿胀 程度优于对照组（P ＜0.05）。结论 对剖宫产患者实施延续性护理干预可提高护理效果,促进伤口愈合, 提升美观度,且有利于提升纯母乳喂养率,提高产妇术后生活质量,减少术后乳房肿胀。     

基于循证医学的产妇手术切口护理对剖宫产切口美观性及情绪状态的影响

目的 探讨基于循证医学的切口护理模式对剖宫产切口美观性及情绪状态的影响。方法 选取 2022年6月-2023年6月南京医科大学附属妇产医院/南京市妇幼保健院行剖宫产的102例初产妇作为研究对 象,随机分为对照组和观察组,每组51例。对照组实施常规护理,观察组则在此基础上予以基于循证医 学的切口护理模式,比较两组患者瘢痕评价量表（PSAS）、观察者瘢痕评价量表（OSAS）、皮肤科生 活质量指数（DLQI）、Zung抑郁自评量表（Zung-SDS）等级以及Zung焦虑自评量表（Zung-SAS）。 结果 观察组PSAS、OSAS、DLQI各维度评分及总分低于对照组（P ＜0.05）;观察组Zung-SDS抑郁等 级、（Zung-SAS）焦虑等级优于对照组（P＜0.05）。结论 基于循证医学的产妇手术切口护理有助于改善 术后切口美观度,提高生活质量,减轻其心理压力,降低抑郁和焦虑的发生率。     

罗哌卡因蛛网膜下隙阻滞在新式剖宫产术中的应用

①目的　探讨罗哌卡因蛛网膜下隙阻滞用于新式剖宫产术的安全性、可行性和适宜剂量。②方法选择择期剖宫产术孕妇 1 5 0例 ,ASAⅠ～Ⅱ级 ,采用L2～ 3 或L3～ 4腰椎 硬膜外联合麻醉。随机分为 3组 ,每组 5 0例 ,Ⅰ组注入轻比密度 5 g/L布比卡因 2mL ,Ⅱ组注入轻比密度 7.5 g/L罗哌卡因 2mL ,Ⅲ组注入轻比密度 5 g/L罗哌卡因 2mL。对腹壁肌肉松弛不理想者 ,硬膜外腔追加 1 6 g/L利多卡因碱性液 5～ 8mL。观察各组感觉和运动阻滞时间、腹壁肌肉松弛质量、新生儿Apgar评分及不良反应。 ③结果　Ⅲ组达到最大阻滞时间和运动阻滞起效时间较其他两组延长 ,差异有显著性 (F =6 .2 8、1 6 .5 1 ,q =4 .1 2～ 7.88,P <0 .0 1 ) ;感觉阻滞起效时间和 5min新生儿Apgar评分 3组间无明显差异 ;运动恢复时间和阻滞持续时间Ⅰ组 >Ⅱ组 >Ⅲ组 (F =4 5 .73、1 88.90 ,q =4 .1 2～ 1 3.2 1 ,P <0 .0 1 ) ;腹壁肌松质量Ⅰ组和Ⅱ组优于Ⅲ组 ;胎儿娩出时间Ⅲ组长于Ⅰ、Ⅱ组 (F =1 0 4 .1 0 ,q =1 7.38、1 7.39,P <0 .0 1 ) ;循环系统干扰Ⅰ组较其他两组为重 (u =2 .2 4 5 ,P <0 .0 5 )。④结论　 7.5 g/L轻比密度罗哌卡因蛛网膜下隙阻滞用于新式剖宫产术安全、有效     

剖宫产技术值得关注的问题

剖宫产术是产科最常用的手术方式,恰当稳妥的实施手术是保证母婴安全的保障。本文阐述了在剖宫产手术中值得关注的几个问题,并提出对高危因素进行有效规避的方法,减少手术并发症的发生。