Experiment and Theoretical Investigation on Fatigue Life Prediction of Fracturing Pumpheads Based on a Novel Stress-Field Intensity Approach

Fracturing pumpheads are typical pressure vessels that experience frequent fatigue failure under the effect of notches in their cross-bore. To enhance the fatigue life of fracturing pumpheads, the study of the notch effect is indispensable and important to establish a reliable mathematical model to predict their fatigue life. In the present paper, two novel fatigue life prediction models are proposed for notched specimens. In these models, two new geometric fatigue failure regions are defined to improve the weight function. Finally, the elaborated novel stress-field intensity approach was applied to three different types of notched specimens. Experiment results indicate that the new SFI approach achieves 47.82%, 39.48%, and 31.85% higher prediction accuracy than the traditional SFI approach, respectively. It was found that the modified SFI approach provided better predictions than the traditional SFI approach and the TCD method. The II-th novel SFI approach had the highest accuracy, and the I-th novel SFI approach was more suitable for sharply notched specimens.     

Magnetoacoustic Wave Scattering and Dynamic Stress Concentration around the Elliptical Opening in Exponential-Gradient Piezomagnetic Materials

Based on the theory of magnetoacoustic coupled dynamics, the purpose of this paper is to evaluate the dynamic stress concentration near an elliptical opening in exponential-gradient piezomagnetic materials under the action of antiplane shear waves. By the wave function expansion, the solutions for the acoustic wave fields and magnetic fields can be obtained. Stress analysis is performed by the complex function method and the conformal mapping method, which are used to solve the boundary conditions problem, and is used to express the dynamic stress concentration coefficient (DSCC) theoretically. As cases, numerical results of DSCCs are plotted and discussed with different incident wave numbers and material parameters by numerical simulation. Compared with circular openings, elliptical openings are widely used in material processing techniques and are more difficult to solve. Numerical results show that the dynamic stress concentration coefficient at the elliptical opening is strongly dependent on various parameters, which indicates that the elliptical opening is more likely to cause crack and damage to exponential-gradient piezomagnetic materials.     

非酒精性脂肪肝病患者粪便中短链脂肪酸改变的临床研究

目的探索非酒精性脂肪肝病（NAFLD）不同状态下粪便短链脂肪酸（SCFAs）的差异,为寻找NAFLD疾病发生发展机制和可能的治疗靶点提供支持。方法通过气相色谱-质谱分析,检测非酒精性脂肪肝（NAFL）、非酒精性脂肪肝炎（NASH）、NAFLD相关肝硬化粪便中乙酸、丙酸、丁酸三种主要SCFAs水平和构成差异。结果纳入分析80例,其中健康志愿者9例,NAFL患者27例,NASH患者20例,NAFLD相关肝硬化24例。NAFLD相关肝硬化组患者SCFAs总含量（P=0.004,P=0.0001,P=0.001）、粪便丁酸（P=0.045,P=0.0001,P=0.0001）、乙酸水平（P=0.010,P=0.0001,P=0.012）分别显著低于健康志愿者、NAFL组和NASH组,丙酸水平（P=0.024）显著低于NAFL组。NAFLD相关肝硬化组患者SCFAs中丁酸所占比例显著低于NASH组（P=0.016）。结论 NAFLD肝硬化患者粪便存在主要SCFAs水平的降低,其中丁酸构成比例降低更为明显,这可能是NAFLD进入肝硬化特征改变之一,提示SCFAs水平变化对NAFLD疾病进展可能有一定预测作用,补充肠道SCFAs可能作为NAFLD相关肝硬化新的治疗靶点。     

新型冠状病毒肺炎危重患者睡眠质量与焦虑水平现况调查分析

目的 了解新型冠状病毒肺炎(简称新冠肺炎)危重患者睡眠质量及焦虑水平现状,为调节睡眠提供一定的理论依据.方法 采用一般问卷调查法,使用匹兹堡睡眠指数量表(PSQI)及焦虑自评量表(SAS)对湖北某三甲医院(定点收治)某病区40例危重型COVID-19患者进行调查,应用描述性分析、单因素分析、相关性分析和多元线性回归分析...     

Recovery of complete left bundle branch block in a dilated cardiomyopathy patient after treatment with sacubitril/valsartan: A case report

Rationale:The treatment of dilated cardiomyopathy (DCM) has recently been greatly improved, especially with the widespread use of sacubitril/valsartan (ARNI) combination therapy. We know that ARNI-like drugs can significantly improve the symptoms of heart failure with reducing ejection fraction. However, clinical studies evaluating the safety and efficacy of ARNI in DCM-associated arrhythmia are limited, and whether individuals with arrhythmia would benefit from ARNI remains controversial. In this case, we report a patient with complete left bundle branch block (CLBBB) associated with DCM whose CLBBB returned to normal after treatment with ARNI.Patient concerns:A 38-year-old man was admitted to the hospital for 20 days for idiopathic paroxysmal dyspnea. He presented with exacerbated dyspnea symptoms at night, accompanied by cough and sputum.Diagnosis:Physical examination revealed a grade 4/6 systolic murmur could be heard in the apical area of the heart and mild edema was present in both lower limbs. Laboratory examination found that the B-type natriuretic peptide was significantly increased. Echocardiography indicated left atrial internal diameter, right ventricular internal diameter, and left ventricular diastolic diameter were enlarged and ejection fraction was significantly decreased. Besides, the pulsation of the wall was diffusely attenuated. Electrocardiogram was suggestive of tachycardia and CLBBB. A diagnosis of DCM with CLBBB was considered based on a comprehensive evaluation of the physical examination, laboratory examination, echocardiography and electrocardiogram.Interventions:The patient was treated with ARNI at a dose of 50 mg (twice a day) at first, gradually increasing to the target dose (200 mg, twice a day) in the following 9 months as shown in Table ​Table1,1, along with metoprolol 25 mg (once a day [qd]), diuretics 20 mg (qd), and aldosterone 20 mg (qd).Table 1Specific medications used in treatment.

P2Y12 inhibitor pretreatment in patients with nonST-segment elevation acute coronary syndrome: A meta-analysis

Background:The 2020 European Society of Cardiology guidelines do not recommend pretreatment for nonST-segment elevation myocardial infarction (NSTEMI) patients with unclear coronary anatomy, which is inconsistent with our routine preoperative approach to loading P2Y12 receptor inhibitors (e.g., preoperative loading of 300 mg of clopidogrel).Objectives:The purpose of our study was to compare the safety and effectiveness of P2Y12 inhibitors administered before coronary angiography or at least before percutaneous coronary intervention (PCI) with during or after PCI.Methods:Cochrane, PubMed, and Embase databases were searched. The primary effect endpoint and safety endpoint were any-cause death and major bleeding, respectively. Major adverse cardiovascular events, myocardial infarction and revascularization were also analyzed.Results:Our search identified 9 trials. P2Y12 inhibitor pretreatment was associated with lower death from any cause (OR 0.62, 95% CI 0.53–0.72, P < 0.00001) without increasing the risk of bleeding (OR 1.02, 95% CI 0.80–1.30, P = 0.89). However, prasugrel or ticagrelor pretreatment was not associated with a lower risk of mortality (OR 0.70, 95% CI 0.31–1.59, P = 0.40) and increased the risk of bleeding (OR 1.67, 95% CI 1.10–2.54, P = 0.02).Conclusions:In summary, clopidogrel pretreatment was associated with significantly lower mortality, major adverse cardiovascular events, myocardial infarction and revascularization with no increase in major bleeding. However, these advantages were not observed with prasugrel or ticagrelor pretreatment.     

Risk factors of perioperative complications and management with enhanced recovery after primary surgery in women with epithelial ovarian carcinoma in a single center

The present study aimed to evaluate the postoperative complications and the impact of an enhanced recovery programme in patients who underwent primary surgery (including extensive upper abdominal surgery) for epithelial ovarian carcinoma (EOC). All patients with stage I–IV ovarian carcinoma who underwent primary surgery were identified, and postoperative complications were evaluated and graded according to the Clavien-Dindo classification. Of 161 patients, 46 (28.57%) underwent surgical staging, 27 (16.77%) standard cytoreduction, 12 (7.45%) en bloc debulking and 76 (47.20%) extraradical debulking. A total of 157 patients (97.52%) achieved optimal tumor reduction (<1 cm). The mean postoperative hospitalization time was 17.33±11.29 days after completion of the initial postoperative chemotherapy (IPC), and the IPC interval was 16.22±10.09 days. A total of 13 patients (8.07%) had grade 3 complications (9 with wound dehiscence, 3 with digestive tract leakage and 1 with a bladder fistula). A total of 2 patients (1.24%) had grade 4–5 complications [1 patient with severe pneumonia returned to the intensive care unit (ICU) for tracheotomy and respiration rehabilitation; the other patient died of septicemia on day 19]. The multivariate analysis of the preoperative factors revealed that a human epididymis protein 4 (HE4) level of ≥717 pM (P=0.015) and Federation International of Gynecology and Obstetrics (FIGO) stage IV (P=0.004; compared with stage IIIC) were associated with grade 3–5 complications. The bootstrap analysis revealed that a cancer antigen 125 (CA125) level of ≥1,012 U/ml (P=0.034), a HE4 level of ≥717 pM (P=0.007) and FIGO stage IV (P=0.002; compared with stage IIIC) were significantly associated with grade 3–5 complications. Meanwhile, the multivariate analysis of the postoperative factors did not reveal any risk factors associated with grade 3–5 complications; the bootstrap analysis revealed that only transfer to the ICU after surgery (P=0.026) was significantly associated with grade 3–5 complications. In conclusion, the study found that application of enhanced recovery after surgery protocols is feasible in patients with EOC, especially in those undergoing advanced extensive upper abdominal surgery, and CA125, HE4 and FIGO stage IV were related with the occurrence of adverse perioperative outcomes.     

增智开窍针法对孤独症儿童语言功能的干预作用

目的观察针刺治疗儿童孤独症的临床疗效。方法采用增智开窍针法,选用孤独症治疗评估量表（ATEC）,对32例患儿临床症状进行检测评估。结果针刺治疗后语言交流、人际关系、动作行为、个人能力均有改善,其中语言交流的显效率与其他三项比较,差异有统计学意义（P〈0．05）;治疗前后ATEC评定结果比较,语言项P〈0．01,社交项、感知项、行为项针刺前后比较P〈0．05,差异均有统计学意义。结论针刺能有效改善儿童孤独症患儿的临床症状,对语言功能的干预作用尤为明显。