Impact Analysis of Microscopic Defect Types on the Macroscopic Crack Propagation in Sintered Silver Nanoparticles

Sintered silver nanoparticles(AgNPs)arewidely used in high-power electronics due to their exceptional properties.However,the material reliability is significantly affected by various microscopic defects.In this work,the three primary micro-defect types at potential stress concentrations in sintered AgNPs are identified,categorized,and quantified.Molecular dynamics(MD)simulations are employed to observe the failure evolution of different microscopic defects.The dominant mechanisms responsible for this evolution are dislocation nucleation and dislocation motion.At the same time,this paper clarifies the quantitative relationship between the tensile strain amount and the failure mechanism transitions of the three defect types by defining key strain points.The impact of defect types on the failure process is also discussed.Furthermore,traction-separation curves extracted from microscopic defect evolutions serve as a bridge to connect the macro-scale model.The validity of the crack propagation model is confirmed through tensile tests.Finally,we thoroughly analyze how micro-defect types influence macro-crack propagation and attempt to find supporting evidence from the MD model.Our findings provide a multi-perspective reference for the reliability analysis of sintered AgNPs.

“Hepatic hilum area priority,liver posterior first”:An optimized strategy in laparoscopic resection for type Ⅲ-Ⅳ hilar cholangiocarcinoma

BACKGROUND In recent years,pure laparoscopic radical surgery for Bismuth-Corlette type Ⅲ and Ⅳ hilar cholangiocarcinoma(HCCA)has been preliminarily explored and applied,but the surgical strategy and safety are still worthy of further improvement and attention.AIM To summarize and share the application experience of the emerging strategy of“hepatic hilum area dissection priority,liver posterior separation first”in pure laparoscopic radical resection for patients with HCCA of Bismuth-Corlette types Ⅲ and IV.METHODS The clinical data and surgical videos of 6 patients with HCCA of Bismuth-Corlette types Ⅲ and Ⅳ who underwent pure laparoscopic radical resection in our department from December 2021 to December 2023 were retrospectively analyzed.RESULTS Among the 6 patients,4 were males and 2 were females.The average age was 62.2±11.0 years,and the median body mass index was 20.7(19.2-24.1)kg/m^(2).The preoperative median total bilirubin was 57.7(16.0-155.7)μmol/L.One patient had Bismuth-Corlette type Ⅲa,4 patients had Bismuth-Corlette type Ⅲb,and 1 patient had Bismuth-Corlette type Ⅳ.All patients successfully underwent pure laparoscopic radical resection following the strategy of“hepatic hilum area dissection priority,liver posterior separation first”.The operation time was 358.3±85.0 minutes,and the intraoperative blood loss volume was 195.0±108.4 mL.None of the patients received blood transfusions during the perioperative period.The median length of stay was 8.3(7.0-10.0)days.Mild bile leakage occurred in 2 patients,and all patients were discharged without serious surgery-related complications.CONCLUSION The emerging strategy of“hepatic hilum area dissection priority,liver posterior separation first”is safe and feasible in pure laparoscopic radical surgery for patients with HCCA of Bismuth-Corlette types Ⅲ and Ⅳ.This strategy is helpful for promoting the modularization and process of pure laparoscopic radical surgery for complicated HCCA,shortens the learning curve,and is worthy of further clinical application.

Master crack types and typical acoustic emission characteristics during rock failure

Acoustic emission(AE)signals contain substantial information about the internal fracture characteristics of rocks and are useful for revealing the laws governing the release of energy stored therein.Reported here is the evolution of rock failure with diferent master crack types as investigated using Brazilian splitting tests(BSTs),direct shear tests(DSTs),and uniaxial compression tests(UCTs).The AE parameters and typical modes of each fracture type were obtained,and the energy release characteristics of each fracture mechanism were discussed.From the observed changes in the AE parameters,the rock fracture process exhibits characteristics of staged intensifcation.The scale and energy level of crack activity in the BSTs were signifcantly lower than those in the DSTs and UCTs.The proportion of tensile cracks in the BSTs was 65%–75%,while the proportions of shear cracks in the DSTs and UCTs were 75%–85%and 70%–75%,respectively.During the rock loading process under diferent conditions,failure was accompanied by an increased number of shear cracks.The amplitude,duration,and rise time of the AE signal from rock failure were larger when the failure was dominated by shear cracks rather than tensile ones,and most of the medium-and high-energy signals had medium to low frequencies.After calculating the proposed energy amplitude ratio,the energy release of shear cracks was found to exceed that of tensile cracks at the same fracture scale.

肾组织石蜡切片Ⅳ型胶原α链免疫组织化学染色在诊断Alport综合征中的应用

目的对Alport综合征(AS)患者肾脏穿刺组织进行石蜡切片Ⅳ型胶原α链免疫组织化学检测,探讨其临床应用价值。方法选取2018年11月至2022年7月浙江大学医学院附属第一医院肾脏病中心确诊的10例AS患者(AS病例组)、10例心脏死亡器官捐献者(DCD)供肾及10例确诊为免疫球蛋白A肾病患者(对照组)的肾组织进行石蜡切片Ⅳ型胶原α1、α3、α5链全自动免疫组织化学染色,将其与冰冻切片免疫荧光染色结果进行比较。将对照组肾组织石蜡切片分别采用多种方法进行抗原修复,比较修复效果。结果对照组肾组织2种染色方法Ⅳ型胶原α1、α3、α5链染色在肾小球基底膜(GBM)中均为连续线状阳性表达。AS病例组肾组织2种染色方法Ⅳ型胶原α1链染色在GBM均呈连续线状阳性表达,α3、α5链染色在GBM为阴性或节段弱阳性表达。2种染色方法染色结果具有较高的一致性(Kappa=0.615,P=0.035)。结论石蜡切片全自动免疫组织化学检测Ⅳ型胶原α1、α3和α5能较好地用于AS的诊断,为AS的诊断和研究提供了一种可靠的技术手段。

基于上皮细胞-间充质细胞转分化(EMT)理论的艾灸配合化纤Ⅳ号方对实验大鼠Collagen Type Ⅲ和PDGF干预作用实验研究

目的:基于上皮细胞-间充质细胞转分化(EMT)学说观察化纤Ⅳ号方、艾灸以及二者相配合治疗肺纤维化大鼠Collagen TypeⅢ(Ⅲ-C)和PDGF的变化,探讨其治疗效应及生物学机制。方法:将鼠龄约为6周的SD大鼠随机分为空白组、模型组、化纤Ⅳ号方组、艾灸组、化纤Ⅳ号方与艾灸配合治疗组(简称为"灸药组"),治疗30 d后处死观察其肺组织病理改变,并检测其Collagen TypeⅢ、PDGF的基因和蛋白表达情况。结果:实时荧光定量结果显示:与空白组相比,各组Ⅲ-C和PDGF m RNA表达增高(P<0.05)。与模型组相比,各组的Ⅲ-C和PDGF m RNA表达有明显降低(P<0.01)。而各组中,灸药组疗效最明显,Ⅲ-C和PDGF的表达最低。蛋白免疫印迹法检测结果显示:与模型组相比各组的Ⅲ-C蛋白表达有差异。结论:1艾灸、化纤Ⅳ号方均可减轻博莱霉素诱导肺纤维化大鼠的肺纤维化程度。2艾灸配合化纤Ⅳ号方可减轻博莱霉素诱导肺纤维化大鼠的肺纤维化程度,且其效果优于单用艾灸或单用化纤Ⅳ号方。3艾灸、化纤Ⅳ号方及其二者配合使用不同程度阻抑博莱霉素诱导肺纤维化大鼠肺纤维化进程的效应机制,可能与通过调控其EMT过程中的Ⅲ-C和PDGF表达环节紧密相关。

Collagen type Ⅳ对周围神经中再生轴突及非神经元细胞的作用和影响

本文用抗ｃｏｌｌａｇｅｎｔｙｐｅⅣ对抗体阻断ｃｏｌｌａｇｅｎｔｙｎｅⅣ的方法，研究了ｃｏｌｌａｇｅｎｔｙｐｅⅣ失活的移植神经段（长１０ｍｍ）植入大鼠坐骨神经后对再生轴突和非神经元细胞的作用和影响．实验结果显示：在移植神经段近端距近侧吻合口１ｍｍ处，术后１０ｄ抗ｃｏｌｌａｇｅｎｔｙｐｅⅣ组再生轴突数为对照组的５４％，术后１５ｄ增加到６６％，术后３０ｄ高达９４％．在移植神经段远侧距近侧吻合口９ｍｍ处，术后３０ｄ抗ｃｏｌｌａｇｅｎｔｙｐｅⅣ组再生轴突数为对照组的５８％。表明抗ｃｏｌｌａｇｅｎｔｙｐｅⅣ组再生轴突的生长启动和生长速度明显慢于对照组．巨噬细胞在移植神经段内的滞留数量抗ｃｏｌｌａｇｅｎｔｙｐｅⅣ组明显多于对照组．这些结果揭示ｃｏｌｌａｇｅｎｔｙｐｅⅣ在神经损伤和再生中对促进轴突的生长和维持神经微环境的平衡起着积极的作用．本文对ｃｏｌｌａｇｅｎｔｙｐｅⅣ在神经再生中的作用机制作了初步的分析和探讨。

Serum hyaluronic acid, procollagen type Ⅲ and Ⅳ in histological diagnosis of liver fibrosis

OBJECTIVE: To assess the significance of serum hyaluronic acid (HA), proeollagen type Ⅲ (PCⅢ), collagen type Ⅳ (CⅣ) in the histological diagnosis of liver fibrosis. METHODS: The concentrations of serum HA, PCⅢ, CⅣ in 253 patients with chronic liver diseases were measured by radioimmunoassay. Liver biopsies were performed in all patients at the same time. The liver was pathologically evaluated by a pathologist according to a scoring system. Combined with the results of liver pathological diagnosis, the accuracy of serum HA, PCⅢ, CⅣ in diagnosing patients with hepatic fibrosis (staging≥S_2) or cirrhosis (S_4) was assessed using the receiver operating curve (ROC). RESULTS: The cutoff values of serum HA, PCⅢ and CⅣ for identifying patients with hepatic fibrosis (≥S_2) or cirrhosis (S_4) were determined. The cutoff values of serum HA, PCⅢ and CⅣ for detecting patients with fibrosis (stage≥S_2) were 90μg/L, 90μg/L, 75μg/L, respectively; their sensitivity (Se) was 80.4%, 82%, 63.1%; their specificity (Spe) was 70.2%, 60.8%, 83.8%; their positive predictive values (PPV) were 86.7%, 83.5%, 90.4%; their negative predictive values (NPV) were 59.8%, 58.4%, 48.4%, respectively. The cutoff values for detecting patients with liver cirrhosis were 210μg/L for HA, 96.2% for Se, 85.3% for Spe, 65.4% for PPV, 98.8% for NPV; 150μg/L for PCⅢ, 76.4% for Se, 68.7% for Spe, 40.4% for PPV, 91.3% for NPV; 90μg/L for CⅣ, 80% for Se, 75.8% for Spe, 47.8% for PPV, 93.2% for NPV, respectively. CONCLUSIONS: Serum HA, PCⅢ and CⅣ can be determined for an accurate diagnosis of hepatic fibrosis in various stages. HA is the best for screening liver cirrhosis.

Macroscopic appearance of TypeⅣand giant Type Ⅲ is a high risk for a poor prognosis in pathological stage Ⅱ/Ⅲ advanced gastric cancer with postoperative adjuvant chemotherapy

AIM To evaluate whether a high risk macroscopic appearance(Type Ⅳ and giant Type Ⅲ) is associated with a dismal prognosis after curative surgery, because its prognostic relevance remains elusive in pathological stage Ⅱ/Ⅲ(p Stage Ⅱ/Ⅲ) gastric cancer.METHODS One hundred and seventy-two advanced gastric cancer(defined as pT2 or beyond) patients with p Stage Ⅱ/Ⅲ who underwent curative surgery plus adjuvant S1 chemotherapy were evaluated, and the prognostic relevance of a high-risk macroscopic appearance was examined. RESULTS Advanced gastric cancers with a high-risk macroscopic appearance were retrospectively identified by preoperative recorded images. A high-risk macroscopic appearance showed a significantly worse relapse free survival(RFS)(35.7%) and overall survival(OS)(34%) than an average risk appearance(P = 0.0003 and P < 0.0001, respectively). A high-risk macroscopic appearance was significantly associated with the 13^(th) Japanese Gastric Cancer Association(JGCA) pT(P = 0.01), but not with the 13^(th) JGCA pN. On univariate analysis for RFS and OS, prognostic factors included 13^(th) JGCA p Stage(P < 0.0001)and other clinicopathological factors including macroscopic appearance. A multivariate Cox proportional hazards model for univariate prognostic factors identified highrisk macroscopic appearance(P = 0.036, HR = 2.29 for RFS and P = 0.021, HR = 2.74 for OS) as an independent prognostic indicator. CONCLUSION A high-risk macroscopic appearance was associated with a poor prognosis, and it could be a prognostic factor independent of 13^(th) JGCA stage in p Stage Ⅱ/Ⅲ advanced gastric cancer.

Acoustic emission assessment of interface cracking in thermal barrier coatings

In this paper,acoustic emission（AE） and digital image correlation methods were applied to monitor interface cracking in thermal barrier coatings under compression.The interface failure process can be identifie via its AE features,including buckling,delamination incubation and spallation.According to the Fourier transformation of AE signals,there arefourdifferentfailuremodes：surfaceverticalcracks,opening and sliding interface cracks,and substrate deformation.The characteristic frequency of AE signals from surface vertical cracks is 0.21 MHz,whilst that of the two types of interface cracks are 0.43 and 0.29 MHz,respectively.The energy released of the two types of interface cracks are 0.43 and 0.29 MHz,respectively.Based on the energy released from cracking and the AE signals,a relationship is established between the interface crack length and AE parameters,which is in good agreement with experimental results.

Genomic characteristics of Dickeya fangzhongdai isolates from pear and the function of type Ⅳ pili in the chromosome

Dickeya fangzhongdai, the causal agent of bleeding canker of pear, is a new member of the Dickeya genus and the only one that infects woody plants. Recent studies have reclassified several Dickeya isolates as D. fangzhongdai, which were isolated from various environments, including water, Phalaenopsis sp. and Aglaonema sp. To provide genomic characterization of D. fangzhongdai isolates from pear, the genomes of D. fangzhongdai strain JS5(=China General Microbiological Culture Collection Center, CGMCC 1.15464 ~T=DSM 101947 ~T), along with two other isolates, LN1 and QZH3, were sequenced and compared to those of other Dickeya spp. Homology greater than 99% was observed among three D. fangzhongdai strains. Plasmid, type IV secretion system(T4 SS) and type IV pili(TFPs) were found in genomes of D. fangzhongdai isolates. Comparative analysis of the type Ⅲ secretion systems(T3 SS), type Ⅲ secretion effectors(T3 SE), plant cell wall degradation enzymes(PCWDE) and membrane transport proteins of Dickeya spp. showed some differences which might reflect the variations of virulence, phylogenetic and phenotypic characteristics of Dickeya spp. In addition, deletion mutant of TFP in D. fangzhongdai JS5 showed no twitching motility and reduced virulence and biofilm formation. The fingdings of the distinctive plasmid, T4 SS and TFPs, as well as the differences of T3 SE, PCWDE and membrane transport proteins make D. fangzhongdai isolates unique. These results also suggested that acquisition of virulence genes by horizontal gene transfer might play some role in the genetic variation of D. fangzhongdai.

Subtotal gastrectomy combined with chemotherapy: An effective therapy for patients with circumscribed Borrmann type Ⅳ gastric cancer

BACKGROUND Although Borrmann type Ⅳ(B-4) gastric cancer has a higher mortality rate and presents distant metastasis easily, especially peritoneal metastasis, when diagnosed, some B-4 patients were found to have no distant metastasis by preoperative detection and underwent curative surgery, which was defined as circumscribed B-4 in our study. In this study, we focused on the circumscribed B-4 patients without distant metastasis during surgery to identify factors related to prognosis and postoperative peritoneal cavity metastasis(PPCM), which is important for selecting an appropriate therapeutic strategy.AIM To identify factors related to the prognosis and PPCM of B-4 patients.METHODS A total of 117 B-4 patients who underwent gastrectomy between January 2005 and December 2012 were included in this study. Survival analysis was performed using Kaplan–Meier analysis and Cox multivariate models. Pearson correlation analyses were performed to identify the factors related to PPCM. All statistical analyses were performed using SPSS 20.0.RESULTS Lymph node status, gastrectomy type, and postoperative chemotherapy were independent prognostic factors in 117 circumscribed B-4 patients. Subtotal gastrectomy combined with chemotherapy could significantly improve the longterm survival time. Six patients who were diagnosed with pN0 and received the combination therapy had a 3-year survival rate of 100% and a median survival of 77.7 mo. Even for patients with metastatic lymph nodes(n = 13), the combination therapy also increased the 3-year overall survival rate to 57.1%. In addition, positive lymph node status was the only factor(P = 0.005) correlated with PPCM in certain B-4 patients, and chemotherapy was useful for suppressing PPCM in patients with subtotal gastrectomy but not in those with total gastrectomy.CONCLUSION Lymph node status is an independent prognostic factor for circumscribed B-4 patients. In addition, subtotal gastrectomy and postoperative chemotherapy could effectively improve prognosis and even suppress PPCM.

Serum type Ⅳ collagen level is predictive for esophageal varices in patients with severe alcoholic disease

AIM: To determine factors predictive for esophageal varices in severe alcoholic disease (SAD). METHODS: Abdominal ultrasonography (US) was performed on 444 patients suffering from alcoholism. Forty-four patients found to have splenomegaly and/ or withering of the right liver lobe were defined as those with SAD. SAD patients were examined by upper gastrointestinal (UGI) endoscopy for the presence of esophageal varices. The existence of esophageal varices was then related to clinical variables. RESULTS: Twenty-five patients (56.8%) had esophageal varices. A univariate analysis revealed a significant difference in age and type Ⅳ collagen levels between patients with and without esophageal varices. A logistic regression analysis identified type Ⅳ collagen as the only independent variable predictive for esophageal varices (P = 0.017). The area under the curve (AUC) for type Ⅳ collagen as determined by the receiver operating characteristic (ROC) for predicting esophageal varices was 0.78. CONCLUSION: This study suggests that the level of type Ⅳ collagen has a high diagnostic accuracy for the detection of esophageal varices in SAD.

Significance of regenerating islet-derived type Ⅳ gene expression in gastroenterological cancers

The regenerating islet-derived members (Reg ),a group of small secretory proteins,which are involved in cell proliferation or differentiation in digestive organs,are upregulated in several gastrointestinal cancers,functioning as trophic or antiapoptotic factors.Regenerating islet-derived type Ⅳ (RegⅣ ),a member of the Reg gene family,has been reported to be overexpressed in gastroenterological cancers.RegIV overexpression in tumor cells has been associated with carcinogenesis,cell growth,survival and resistance to apoptosis.Cancer tissue expressing RegⅣ is generally associated with more malignant characteristics than that without such expression,and RegⅣ is considered a novel prognostic factor as well as diagnostic marker in some gastroenterological cancers.We previously investigated the expression levels of RegⅣ mRNA of 202 surgical colorectal cancer specimens with quantitative real-time reverse-transcriptase polymerase chain reaction and reported that a higher level of RegⅣ gene expression was a significant independent predictor of colorectal cancer.The biologic functions of RegⅣ protein in cancer tissue,associated with carcinogenesis,antiapoptosis and invasiveness,are being elucidated by molecular investigations using transfection techniques or neutralizing antibodies of RegⅣ,and the feasibility of antibody therapy targeting RegⅣ is being assessed.These studies may lead to novel therapeutic strategies for gastroenterological cancers expressing RegⅣ .This review article summarizes the current information related to biological functions as well as clinical importance of RegⅣ gene to clarify the significance of RegⅣ expression in gastroenterological cancers.

Evaluation method of cracking resistance of lightweight aggregate concrete

The cracking behavior of lightweight aggregate concrete(LWAC) was investigated by mechanical analysis, SEM and cracking-resistant test where a shrinkage-restrained ring with a clapboard was used. The relationship between the ceramsite type and the cracking resistance of LWAC was built up and compared with that of normal-weight coarse aggregate concrete(NWAC). A new method was proposed to evaluate the cracking resistance of concrete, where the concepts of cracking coefficient ζt(t) and the evaluation index Acr(t) were proposed, and the development of micro-cracks and damage accumulation were recognized. For the concrete with an ascending cracking coefficient curve, the larger Acr(t) is, the lower cracking resistance of concrete is. For the concrete with a descending cracking coefficient curve, the larger Acr(t) is, the stronger the cracking resistance of concrete is. The evaluation results show that in the case of that all the three types of coarse aggregates in concrete are pre-soaked for 24 h, NWAC has the lowest cracking resistance, followed by the LWAC with lower water absorption capacity ceramsite and the LWAC with higher water absorption capacity ceramsite has the strongest cracking resistance. The proposed method has obvious advantages over the cracking age method, because it can evaluate the cracking behavior of concrete even if the concrete has not an observable crack.

Pre-hepatectomy type Ⅳ collagen 7S predicts post-hepatectomy liver failure and recovery

BACKGROUND Liver resection is an effective treatment for benign and malignant liver tumors.However,a method for preoperative evaluation of hepatic reserve has not yet been established.Previously reported assessments of preoperative hepatic reserve focused only on liver failure in the early postoperative period and did not consider the long-term recovery of hepatic reserve.When determining eligibility for hepatectomy,the underlying pathophysiology needs to be considered to determine if the functional hepatic reserve can withstand both surgery and any postoperative therapy.AIM To identify pre-hepatectomy factors associated with both early postoperative liver failure and long-term postoperative liver function recovery.METHODS This study was a retrospective cohort study.We retrospectively investigated 215 patients who underwent hepatectomy at our hospital between May 2013 and December 2016.Early post-hepatectomy liver failure(PHLF)was defined using the International Study Group of Liver Surgery’s definition of PHLF.Long-term postoperative recovery of liver function was defined as the time taken for serum total bilirubin and albumin levels to return to levels of<2 mg/dL and>2.8 g/dL,respectively,and the time taken for Child-Pugh score to return to Child-Pugh class A.RESULTS Preoperative type IV collagen 7S was identified as a significant independent factor associated with both PHLF and postoperative long-term recovery of liver function.Further analysis revealed that the time taken for the recovery of Child-Pugh scores and serum total bilirubin and albumin levels was significantly shorter in patients with type IV collagen 7S≤6 ng/mL than in those with type IV collagen 7S>6 ng/mL.In additional analyses,similar results were observed in patients without chronic viral hepatitis associated with fibrosis.CONCLUSION Preoperative type IV collagen 7S is a preoperative predictor of PHLF and longterm postoperative liver function recovery.It can also be used in patients without chronic hepatitis virus.

Hypertension, type Ⅳ cardiorenal syndrome and chronic kidney disease: Pathophysiological and therapeutical approach

Hypertension represent one of the most important comorbid factors in chronic kidney disease(CKD) patients and its prevalence increases from 65% to 95% according to glomerular filtration rate decline. CKD patients need to maintain their blood pressure levels into 130/80 mm Hg according to most recent guidelines. Despite of many therapeutic agents, achievement of ideal blood pressure levels remains so far from the ideal ones. Hypertensive disease represent most important risk factor to develop a type Ⅳ cardiorenal syndrome, while prevalence of end stage renal disease is still raising and it represents worldwide epidemiological challenge. Correct management of hypertensive disease can obtain better control on CKD progression.

Ⅳ类石英玻璃光学均匀性影响因素研究

Ⅳ类石英玻璃是一种重要的特种玻璃材料,在光学探测、惯性导航等领域内具有重要作用。光学均匀性是表征光学玻璃结构均匀性的一种重要方法,Ⅳ类石英玻璃的光学均匀性与硅氧网络结构分布一致性密切相关。本文通过四步法光学均匀性测试、紫外-可见-近红外光谱、红外反射光谱等方法,研究了羟基、金属杂质及氧缺陷的径向分布特点和硅氧键键角的径向变化,采用相关性分析研究了各影响因素对样品光学均匀性的影响。结果表明:表示玻璃光学均匀性的波前畸变t_(0)Δn沿玻璃半径先降低后升高;羟基的径向分布整体上与t_(0)Δn的径向变化相反,200 nm处透过率径向变化、硅氧键键角径向变化与t_(0)Δn的径向变化相近;羟基对Ⅳ类石英玻璃光学均匀性的影响较小,金属杂质、氧缺陷及硅氧键键角的径向变化是影响Ⅳ类石英玻璃光学均匀性的主要因素。

Conservative management of small bowel perforation in Ehlers-Danlos syndrome type Ⅳ

Ehlers-Danlos syndrome (EDS) is a group of inherited connective tissue disorders caused by collagen synthesis defects. EDS type Ⅳ, or vascular EDS, is caused by loss-of-function mutations in the type Ⅲ pro-collagen gene (COL3A1 ). Common complications of EDS type IV include gastrointestinal bleeding and bowel perforations, posing diagnostic and therapeutic dilemmas for both surgeons and gastroenterologists. Here, we describe a complicated case of EDS type Ⅳ in a 35-year-old caucasian female who presented with overt gastro-intestinal bleeding. The patient had a prior history of spontaneous colonic perforation, and an uncomplicated upper endoscopy was performed. A careful ileoscopy was terminated early due to tachycardia and severe ab-dominal pain, and a subsequent computed tomography scan confirmed the diagnosis of ileal perforation. The patient was managed conservatively, and demonstrated daily improvement. At the time of hospital discharge, no further episodes of gastrointestinal blood loss had occurred. This case highlights the benefit of conservative management for EDS patients with gastrointestinal hemorrhage. It is recommended that surgical treatmentshould be reserved for patients who fail conservative treatment or in cases of hemodynamic instability. Finally, this case demonstrates the necessity for a higher threshold of operative or endoscopic interventions in EDS type Ⅳ patients.

Characterization of the Type IV crack in high Cr steel weldments

The weldments for several types of high Cr ferritic steels were investigated to understand the fracture mechanism of the Type IV crack. The creep testing shows that the Type IV cracking is more likely to occur at the lower stress level, whereas at the higher stress level the crack shifts towards parent metal. The microstructures observed in the HAZ for all the materials are mostly tempered lath martensites. There was no δ ferrites found in all creep specimens.

AN INVESTIGATION OF RANDOM FATIGUE STRENGTH OF K-TYPE TUBULAR JOINTS AND CRACK PROPAGATION BEHAVIORS

Random fatigue of welded K-type tubular joints subjected to axial or out-of-plane bending load is analyzed. By considering the sizes of initial surface cracks and material constants as random variables with some probabilistic distributions, incorporating the effect of the weld, five hundred random samples are generated. Statistical computational results of life of crack propagation and effect of change of crack shape are finally obtained and compared with experimental data available based on a regression analysis. Meanwhile, crack propagation behaviors are also investigated.