Endoscopic treatment of difficult extrahepatic bile duct stones, EPBD or EST: An anatomic view

Large bile duct stone(> 10 mm) or multiple stones(≥ 3) are challenging for endoscopists. Endoscopic sphincterotomy(EST) is a routine therapeutic endoscopic retrograde cholangiopancreatography(ERCP) procedure usually used. It is safe and effective, but severe perforation or massive bleeding are the main causes of mortality. Because of the permanent destroy ofOddi sphincter, the use of EST is still controversial. Endoscopic papillary balloon dilation(EPBD) gives another way to open the sphincter. Less incidence of bleeding, perforation and partly preserving the Oddi sphincter's function are the main advantages. But high incidence of post-ERCP pancreatitis becomes a predominant problem. According to the anatomical feature of Oddi sphincter, limited EST + EPBD seems a more reasonable procedure. Compared to the former two procedures, it makes the stone extraction process much easier with lower incidences of short-term and long-term complications.

Numerical investigations of thermal mixing performance of a hot gas mixing structure in high-temperature gas-cooled reactor

A numerical simulation study was performed to clarify the thermal mixing characteristics of coolant in the core bottom structure of the high-temperature gas-cooled reactor(HTR). The flow field and temperature field in the hot gas chamber and the hot gas duct of the HTR were obtained based on the commercial computational fluid dynamics(CFD) program. The numerical simulation results showed that the helium flow with different temperatures in the hot gas mixing chamber and the hot gas duct mixed intensively, and the mixing rate of the temperature in the outlet of the hot gas duct reached 98 %. The results indicated many large-scale swirling flow structures and strong turbulence in the hot gas mixing chamber and the entrance of the hot gas duct, which were responsible for the excellent thermal mixing of the hot gas chamber and the hot gas duct. The calculated results showed that the temperature mixing rate of the hot gas chamber decreased only marginally with increasing Reynolds number.

Increased index of microcirculatory resistance in older patients with heart failure with preserved ejection fraction

Objective To study the coronary microvascular function in older patients with heart failure with preserved ejection fraction (HFpEF) using an invasive pressure–temperature sensor guidewire. Methods Patients undergoing echocardiography and cardiac catheterization examinations for exertional dyspnea and a positive stress test were retrospectively enrolled from January 2014 to November 2017, and were allocated into the control group or HFpEF group. The HFpEF group was secondary divided into two groups according to the age of 65 years. Comparing the clinical features and values obtained in examinations between the three groups, multivariate regression analysis was used to analyze the predictors of left ventricle end diastolic pressure (LVEDP). Results There were 87 patients enrolled in this study. The older HFpEF patients (n = 32) were more likely to be female;and had the most comorbidities, such as diabetes mellitus, atrial fibrillation, and chronic kidney dysfunction (CKD) with a low estimated glomerular filtration rate (eGFR), and had a similar hypertensive prevalence as the adult HFpEF group (n = 24), whose mean LVEDP and index of microcirculatory resistance (IMR) were highest in comparison to the adult HFpEF patients and controls (n = 31). The coronary flow reserve (CFR) in the older HFpEF and adult HFpEF groups was similarly reduced. In the regression analysis, the IMR linearly correlated to LVEDP, and was the only independent predictor of LVEDP. Conclusions An increased IMR and reduced CFR were characteristics of microvascular dysfunction in older HFpEF patients. The IMR independently had a positive linear correlation with LVEDP. Microvascular rarefaction might be a subsequent pathological progression in the development of HFpEF.

MutL homolog 1 germline mutation c.(453+1_454-1)_(545+1_546-1)del identified in lynch syndrome:A case report and review of literature

BACKGROUND Lynch syndrome(LS)is an autosomal dominant hereditary disorder because of germline mutations in DNA mismatch repair genes,such as MutL homolog 1(MLH1),PMS1 homolog 2,MutS homolog 2,and MutS homolog 6.Gene mutations could make individuals and their families more susceptible to experiencing various malignant tumors.In Chinese,MLH1 germline mutation c.(453+1_454-1)_(545+1_546-1)del-related LS has been infrequently reported.Therefore,we report a rare LS patient with colorectal and endometrioid adenocarcinoma and describe her pedigree characteristics.CASE SUMMARY A 57-year-old female patient complained of irregular postmenopausal vaginal bleeding for 6 mo.She was diagnosed with LS,colonic malignancy,endometrioid adenocarcinoma,secondary fallopian tube malignancy,and intermyometrial leiomyomas.Then,she was treated by abdominal hysterectomy,bilateral oviduct oophorectomy,and sentinel lymph node resection.Genetic testing was performed using next-generation sequencing technology to detect the causative genetic mutations.Moreover,all her family members were offered a free genetic test,but no one accepted it.CONCLUSION No tumor relapse or metastasis was found in the patient during the 30-mo followup period.The genetic panel sequencing showed a novel pathogenic germline mutation in MLH1,c.(453+1_454-1)_(545+1_546-1)del,for LS.Moreover,cancer genetic counseling and testing are still in the initial development state in China,and maybe face numerous challenges in the further.

Congenital dysfibrinogenemia misdiagnosed and inappropriately treated as acute fatty liver in pregnancy:A case report and review of literature

BACKGROUND The purpose of this study was to report the rare case of a pregnant woman with congenital dysfibrinogenemia(CD)misdiagnosed as acute fatty liver.She was treated according to the principles of acute fatty liver but achieved good clinical results.CASE SUMMARY A 30-year-old woman presented with 39(6/7)wk of menopause and 6 h of irregular abdominal pain and attended our hospital.Emergency surgery was performed due to fetal distress.Postoperative management followed the treatment principle of acute fatty liver.DNA sequencing was carried out on the pregnant woman and her pedigree.Coagulation values of the patient on admission were prothrombin time 33.7 s,activated partial thromboplastin time 60.4 s,thrombin time 45.2 s,and fibrinogen 0.60 g/L.DNA sequencing results showed that the woman carried a pathogenic heterozygous variation of the fibrinogen alpha chain gene(FGA),which is closely related to hereditary fibrinogen abnormality,and the mutation site was located in p.R350H.After a follow-up period of 12 mo,the mother and her newborn had a good prognosis without bleeding or thrombosis.CONCLUSION Pregnant women with CD may have atypical symptoms,which can easily lead to misdiagnosis.In addition,treatment can be attempted according to the principles of acute fatty liver management.This rare pregnant patient with CD was caused by a novel FGA(p.R350H)gene mutation.

The interactions between bloodstream and vascular structure on aortic dissecting aneurysmal model: A numerical study

Stent-graft implantation is an important means of clinical treatment for aortic dissecting aneurysm （ADA）. However, researches on fluid dynamics effects of stent were rare. Computer simulation was used to investigate the interactions between bloodstream and vascular structure in a stented ADA, which endures the periodic pulse velocity and pressure. We obtained and analyzed the flow velocity distribution, the wall displacement and wall stress in the ADA. By comparing the different results between a non-stented and a stented ADA, we found that the insertion of a vascular graft can make the location of maximum stress and displacement move from the aneurysm lumen wall to the artery wall, accompanied with a greatly decrease in value. These results imply that the placement of a stent-graft of any kind to oc-clude ADA will result in a decreased chance of rupture.

Effects of fluid recirculation on mass transfer from the arterial surface to flowing blood

The effect of disturbed flow on the mass trans- fer from arterial surface to flowing blood was studied nu- merically, and the results were compared with that of our previous work. The arterial wall was assumed to be vis- coelastic and the blood was assumed to be incompressible and non-Newtonian fluid, which is more close to human arte- rial system. Numerical results indicated that the mass trans- fer from the arterial surface to flowing blood in regions of disturbed flow is positively related with the wall shear rates and it is significantly enhanced in regions of disturbed flow with a local minimum around the reattachment point which is higher than the average value of the downstream. There- fore, it may be implied that the accumulation of cholesterol or lipids within atheromatous plaques is not caused by the reduced efflux of cholesterol or lipids, but by the infiltration of the LDL （low-density lipoprotein） from the flowing blood to the arterial wall.

Modeling and Analysis of Interstand Tension Control in 6-high Tandem Cold Rolling Mill

The interstand tension control is one of the most important ways to meet tight tolerances for strip product quality during tandem cold rolling process. Using coordinate analysis and parabolic approximation for the mass flow balance principle, the strip velocities eliminating the use of forward slips and backward slips were calculated. In order to reduce the effect of roll eccentricity on the tension measurement, a filter based on bilinear transformation was de- signed. Applying a first-order Taylor series approximation, the transfer function matrix model of interstand tension stress was derived. The actual measurements on-site and the final calculation results showed that the established model had high calculation accuracy and was beneficial for interstand tension control of random cold rolling process.

Hepatic Perfusion Alterations in Septic Shock Patients： Impact of Early Goal-directed Therapy

Background： Early goal-directed therapy （EGDT） has become an important therapeutic management in early salvage stage of septic shock. However, splenic organs possibly remained hypoperfused and hypoxic despite fluid resuscitation. This study aimed to evaluate the effect of EGDT on hepatic perfusion in septic shock patients. Methods： A prospective observational study was carried out in early septic shock patients who were admitted to Intensive Care Unit within 24 h after onset and who met all four elements of the EGDT criteria after treatment with the standard EGDT procedure within 6 h between December 1, 2012 and November 30, 2013. The hemodynamic data were recorded, and oxygen metabolism and hepatic functions were monitored. An indocyanine green clearance test was applied to detect the hepatic perfusion. The patients＇ characteristics were compared before treatment （TO）, immediately after EGDT （T 1 ）, and 24 h after EGDT （T2）. This study is registered at ClinicalTrials.org, NCT02060773. Results： Twenty-one patients were included in the study; however, the hepatic perfusion data were not included in the analysis for two patients： therefore, 19 patients were eligible for the study. Hemodynamics data, as monitored by pulse-indicator continuous cardiac output, were obtained from 16 patients. There were no significant differences in indocyanine green plasma disappearance rate （ICG-PDR） and 15-min retention rate （Rl 5） at TO （ 11.9 ±5.0%/min and 20.0 ±13.2%）, T1 （ 11.4 ± 5.1%/min and 23.6 ± 14.9%）, and T2 （ 11.0 ±4.5%/rain and 23.7 ± 15.3%） （all P 〉 0.05）. Both of the alterations of ICG-PDR and R l 5 showed no differences at TO, T1, and T2 in the patients of different subgroups that achieved different resuscitation goal numbers when elected （P 〉 0.05）.

Effect of carbon addition on creep behavior of cast TiAl alloy with hard-oriented directional lamellar microstructure

Two TiAl alloys,Ti-47.5Al-3.7(Cr,V,Zr)and Ti-47.5Al-3.7(Cr,V,Zr)-0.1C(at.%),were prepared by cold crucible levitation melting to couple the hard-oriented directional lamellar microstructure with carbon microalloying strengthening.The creep behavior and mechanism for the improvement in creep properties by carbon addition were investigated by mechanical tests and electron microscopy characterizations.The results show that obvious improvements on the creep properties at 760°C and 276 MPa are achieved by 0.1 at.%C addition into TiAl alloy with directional lamellar microstructure,which promotes the creep strain and minimum creep rate decreasing with a large content.The minimum creep rate is reduced from 4.37×10^(-8) to 3.97×10^(-9) s^(-1),and the duration entering into creep acceleration is prolonged for more than 10 times.The mechanism for creep property improvement by 0.1%C addition is attributed to two aspects.The first one is that Ti_(2) AlC is found to be strong obstacles of 1/2[110]dislocations when moving across the lamellar interface in the carbon containing alloy.The other one is that the in terfacial dislocatio ns are effectively impeded and the release process is hindered by dynamic precipitation of Ti_(3) AlC,which is proposed to be the special mechanism for creep resistance improvement of this hard-oriented directional lamellar microstructure.

Effect of carbon addition on stress rupture properties of a cast TiAl alloy

Two TiAl alloys,Ti^47.5Al-3.7(Cr,V,Zr)and Ti77.5Al-3.7(Cr,V,Zr)-0.1C(at.%),were melted and cast with the same process,respectively.Microstructures with strongly oriented lamellae were both observed in these two alloys followed by hot isostatic pressing and heat treatment.Ti2AlC carbides were identified in the alloy with C addition.Stress rupture tests were carried out at 800 and 850°C,with tensile stress from 220 to 400 MPa,respectively.It was shown that the alloy with C experienced much longer lives than the other,especially under the condition of 800°C/260 MPa,800°C/300 MPa,850°C/220 MPa,850°C/240 MPa and 850°C/260 MPa.Observation of ruptured specimens revealed that the microstructure stability was improved significantly in the alloy with C addition which is attributed to the strengthening effect of Ti-Al-C carbides.The Ti2AlC carbides mainly increased the resistance of dislocation passing through the interfaces and kept the integrity of the interfaces.And Ti3AlC carbide was formed during stress rupture process,which could not only effectively act as the barrier of dislocation movement inside the lamellae,but also strengthen the lamellae itself.