Dynamic interwell connectivity analysis of multi-layer waterflooding reservoirs based on an improved graph neural network

The analysis of interwell connectivity plays an important role in the formulation of oilfield development plans and the description of residual oil distribution. In fact, sandstone reservoirs in China's onshore oilfields generally have the characteristics of thin and many layers, so multi-layer joint production is usually adopted. It remains a challenge to ensure the accuracy of splitting and dynamic connectivity in each layer of the injection-production wells with limited field data. The three-dimensional well pattern of multi-layer reservoir and the relationship between injection-production wells can be equivalent to a directional heterogeneous graph. In this paper, an improved graph neural network is proposed to construct an interacting process mimics the real interwell flow regularity. In detail, this method is used to split injection and production rates by combining permeability, porosity and effective thickness, and to invert the dynamic connectivity in each layer of the injection-production wells by attention mechanism.Based on the material balance and physical information, the overall connectivity from the injection wells,through the water injection layers to the production layers and the output of final production wells is established. Meanwhile, the change of well pattern caused by perforation, plugging and switching of wells at different times is achieved by updated graph structure in spatial and temporal ways. The effectiveness of the method is verified by a combination of reservoir numerical simulation examples and field example. The method corresponds to the actual situation of the reservoir, has wide adaptability and low cost, has good practical value, and provides a reference for adjusting the injection-production relationship of the reservoir and the development of the remaining oil.

Phase behavior of gas condensate in porous media using real-time computed tomography scanning

The phase behavior of gas condensate in reservoir formations differs from that in pressure-volume-temperature(PVT)cells because it is influenced by porous media in the reservoir formations.Sandstone was used as a sample to investigate the influence of porous media on the phase behavior of the gas condensate.The pore structure was first analyzed using computed tomography(CT)scanning,digital core technology,and a pore network model.The sandstone core sample was then saturated with gas condensate for the pressure depletion experiment.After each pressure-depletion state was stable,realtime CT scanning was performed on the sample.The scanning results of the sample were reconstructed into three-dimensional grayscale images,and the gas condensate and condensate liquid were segmented based on gray value discrepancy to dynamically characterize the phase behavior of the gas condensate in porous media.Pore network models of the condensate liquid ganglia under different pressures were built to calculate the characteristic parameters,including the average radius,coordination number,and tortuosity,and to analyze the changing mechanism caused by the phase behavior change of the gas condensate.Four types of condensate liquid(clustered,branched,membranous,and droplet ganglia)were then classified by shape factor and Euler number to investigate their morphological changes dynamically and elaborately.The results show that the dew point pressure of the gas condensate in porous media is 12.7 MPa,which is 0.7 MPa higher than 12.0 MPa in PVT cells.The average radius,volume,and coordination number of the condensate liquid ganglia increased when the system pressure was between the dew point pressure(12.7 MPa)and the pressure for the maximum liquid dropout,Pmax(10.0 MPa),and decreased when it was below Pmax.The volume proportion of clustered ganglia was the highest,followed by branched,membranous,and droplet ganglia.This study provides crucial experimental evidence for the phase behavior changing process of gas condensate in porous media during the depletion production of gas condensate reservoirs.

Ligation-assisted endoscopic submucosal resection following unroofing technique for small esophageal subepithelial lesions originating from the muscularis propria

BACKGROUND The majority of esophageal subepithelial lesions originating from the muscularis propria(SEL-MPs)are benign in nature,although a subset may exhibit malignant characteristics.Conventional endoscopic resection techniques are time-consuming and lack efficacy for small SEL-MPs.AIM To evaluate the efficacy and safety of ligation-assisted endoscopic submucosal resection(ESMR-L)following unroofing technique for small esophageal SEL-MPs.METHODS From January 2021 to September 2023,17 patients diagnosed with esophageal SEL-MPs underwent ESMR-L following unroofing technique at the endoscopy center of Shenzhen People’s Hospital.Details of clinicopathological characteristics and clinical outcomes were collected and analyzed.RESULTS The mean age of the patients was 50.12±12.65 years.The mean size of the tumors was 7.47±2.83 mm and all cases achieved en bloc resection successfully.The average operation time was 12.2 minutes without any complications.Histopathology identified 2 Lesions(11.8%)as gastrointestinal stromal tumors at very low risk,12 Lesions(70.6%)as leiomyoma and 3 Lesions(17.6%)as smooth muscle proliferation.No recurrence was found during the mean follow-up duration of 14.18±9.62 months.CONCLUSION ESMR-L following roofing technique is an effective and safe technique for management of esophageal SEL-MPs smaller than 20 mm,but it cannot ensure en bloc resection and may require further treatment.

Early detection of pancreatic cancer in patients with recurrent pancreatitis:A case report

BACKGROUND Pancreatic cancer presents a challenge with its low early diagnosis and treatment rates,leading to high metastasis and mortality rates.The median survival time for advanced pancreatic cancer is a mere 3 months.However,there's hope:small pancreatic cancers diagnosed at an early stage(T1)or those less than or equal to 1 cm in diameter boast an impressive 5-year survival rate of nearly 100%.This underscores the critical importance of early pancreatic cancer detection for significantly improving prognosis.CASE SUMMARY Pancreatic cancer,a malignant tumor of the digestive tract,poses challenges in both diagnosis and treatment due to its occult and atypical clinical symptoms.Clinically,patients with recurrent pancreatitis should be vigilant,as it may be indicative of pancreatic cancer,particularly in middle-aged and elderly patients.Here,we presented the case of a patient who experienced recurrent acute pancreatitis within a span of 2 months.During the initial episode of pancreatitis,routine imaging failed to identify the cause of pancreatic cancer.However,upon recurrence of acute pancreatitis,endoscopic ultrasonography(EUS)revealed a space-occupying lesion approximately 1 cm in size in the pancreatic body.Subsequent EUS coupled with fine-needle aspiration examination demonstrated atypical pancreatic gland epithelium.Ultimately,the patient underwent surgery and was diagnosed with an intraductal papillary mucinous tumor of the pancreas(severe epithelial dysplasia,focal cancer).CONCLUSION We recommend EUS for patients with recurrent pancreatitis of unknown etiology to exclude early pancreatic cancer.

The Astrometric Performance of the China Space Station Telescope(CSST)Sky Survey in Extending the Gaia Celestial Reference Frame

The multi-color imaging sky survey conducted by the China Space Station Telescope(CSST)holds significant promise for advancing the development of the celestial reference frame.In this study,we focus on assessing the astrometric performance of the CSST celestial reference frame(CSST-CRF)in extending the Gaia Celestial Reference Frame 3(Gaia-CRF3).First,the orientation precision of the CSST reference frame is evaluated using a simulated set of extragalactic sources with CSST g magnitudes ranging from 18 to 25 mag.The estimated orientation uncertainty caused by random error insignificantly affects the alignment between Gaia-CRF3 and the CSST-CRF.Then,the systematic effect of incomplete CSST sky coverage on the alignment between CSST-CRF and Gaia-CRF3 is discussed by analyzing the differences between the subset of Gaia-CRF3 in the CSST observation region(Gaia-CRF3′)and Gaia-CRF3 as a whole.Using the third International Celestial Reference Frame(ICRF3)S/X band as an intermediate reference frame,the orientation offset between Gaia-CRF3′and GaiaCRF3 is estimated to be 20μas.This offset is marginally larger than the orientation offset between Gaia-CRF3 and the ICRF3,approximately 15μas.The residual spin and glide rate of Gaia-CRF3′are derived from the proper motions,consistent with that of Gaia-CRF3 within the formal error.Finally,we explore the role of CSST in establishing a multi-band celestial reference frame by comparing its limiting magnitude and observation accuracy with existing catalogs in the infrared and ultraviolet bands.Thanks to its broad wavelength coverage and highprecision measurements,CSST is well-positioned to make significant contributions to the development of a multiband celestial reference frame.

Evolutionary-assisted reinforcement learning for reservoir real-time production optimization under uncertainty

Production optimization has gained increasing attention from the smart oilfield community because it can increase economic benefits and oil recovery substantially.While existing methods could produce high-optimality results,they cannot be applied to real-time optimization for large-scale reservoirs due to high computational demands.In addition,most methods generally assume that the reservoir model is deterministic and ignore the uncertainty of the subsurface environment,making the obtained scheme unreliable for practical deployment.In this work,an efficient and robust method,namely evolutionaryassisted reinforcement learning(EARL),is proposed to achieve real-time production optimization under uncertainty.Specifically,the production optimization problem is modeled as a Markov decision process in which a reinforcement learning agent interacts with the reservoir simulator to train a control policy that maximizes the specified goals.To deal with the problems of brittle convergence properties and lack of efficient exploration strategies of reinforcement learning approaches,a population-based evolutionary algorithm is introduced to assist the training of agents,which provides diverse exploration experiences and promotes stability and robustness due to its inherent redundancy.Compared with prior methods that only optimize a solution for a particular scenario,the proposed approach trains a policy that can adapt to uncertain environments and make real-time decisions to cope with unknown changes.The trained policy,represented by a deep convolutional neural network,can adaptively adjust the well controls based on different reservoir states.Simulation results on two reservoir models show that the proposed approach not only outperforms the RL and EA methods in terms of optimization efficiency but also has strong robustness and real-time decision capacity.

Numerical analysis of water-alternating-CO_(2) flooding for CO_(2)-EOR and storage projects in residual oil zones

Residual oil zones(ROZs)have high residual oil saturation,which can be produced using CO_(2) miscible flooding.At the same time,these zones are good candidates for CO_(2) sequestration.To evaluate the coupled CO_(2)-EOR and storage perfor-mance in ROZs for Water-Alternating-CO_(2)(WAG)flooding,a multi-compositional CO_(2) miscible model with molecular diffusion was developed.The effects of formation parameters(porosity,permeability,temperature),operation parameters(bottom hole pressure,WAG ratio,pore volume of injected water),and diffusion coeffcient on the coupled CO_(2)-EOR and storage were investigated.Five points from the CO_(2) sequestration curve and the oil recovery factor curve were selected to help better analyze coupled CO_(2)-EOR and storage.The results demonstrate that enhanced performance is observed when formation permeability is higher and a larger volume of water is injected.On the other hand,the performance diminishes with increasing porosity,molecular diffusion of gas,and the WAG ratio.When the temperature is around 100℃,coupled CO_(2)-EOR and storage performance is the worst.To achieve optimal miscible flooding,it is recommended to maintain the bottom hole pressure(BHP)of the injection well above 1.2 minimum miscibility pressure(MMP),while ensuring that the BHP of the production well remains sufficiently high.Furthermore,the tapered WAG flooding strategy proves to be profitable for enhanced oil recovery,as compared to a WAG ratio of 0.5:1,although it may not be as effective for CO_(2) sequestration.

Analysis of fracture propagation and shale gas production by intensive volume fracturing

This paper presents an integrated study from fracture propagation modeling to gas flow modeling and a correlation analysis to explore the key controlling factors of intensive volume fracturing.The fracture propagation model takes into account the interaction between hydraulic fracture and natural fracture by means of the displacement discontinuity method(DDM)and the Picard iterative method.The shale gas flow considers multiple transport mechanisms,and the flow in the fracture network is handled by the embedded discrete fracture model(EDFM).A series of numerical simulations are conducted to analyze the effects of the cluster number,stage spacing,stress difference coefficient,and natural fracture distribution on the stimulated fracture area,fractal dimension,and cumulative gas production,and their correlation coefficients are obtained.The results show that the most influential factors to the stimulated fracture area are the stress difference ratio,stage spacing,and natural fracture density,while those to the cumulative gas production are the stress difference ratio,natural fracture density,and cluster number.This indicates that the stress condition dominates the gas production,and employing intensive volume fracturing(by properly increasing the cluster number)is beneficial for improving the final cumulative gas production.

Endoscopic mucosal resection with double band ligation versus endoscopic submucosal dissection for small rectal neuroendocrine tumors

BACKGROUND Endoscopic resection remains an effective method for the treatment of small rectal neuroendocrine tumors(NETs)(≤10 mm).Moreover,endoscopic mucosal resection(EMR)with double band ligation(EMR-dB),a simplified modification of EMR with band ligation,is an alternative strategy to remove small rectal NETs.AIM To evaluate the feasibility and safety of EMR-dB for the treatment of small rectal NETs(≤10 mm).METHODS A total of 50 patients with small rectal NETs,without regional lymph node enlargement or distant metastasis confirmed by endoscopic ultrasound,computerized tomography scan,or magnetic resonance imaging,were enrolled in the study from March 2021 to June 2022.These patients were randomly assigned into the EMR-dB(n=25)group or endoscopic submucosal dissection(ESD)group(n=25).The characteristics of the patients and tumors,procedure time,devices cost,complete resection rate,complications,and recurrence outcomes were analyzed.RESULTS There were 25 patients(13 males,12 females;age range 28-68 years old)in the EMR-dB group,and the ESD group contained 25 patients(15 males,10 females;age range 25-70 years old).Both groups had similar lesion sizes(EMR-dB 4.53±1.02 mm,ESD 5.140±1.74 mm;P=0.141)and resected lesion sizes(1.32±0.52 cm vs 1.58±0.84 cm;P=0.269).Furthermore,the histological complete resection and en bloc resection rates were achieved in all patients(100%for each).In addition,there was no significant difference in the complication rate between the two groups.However,the procedure time was significantly shorter and the devices cost was significantly lower in the EMRdB group.Besides,there was no recurrence in both groups during the follow-up period.CONCLUSION The procedure time of EMR-dB was shorter compared with ESD,and both approaches showed a similar curative effect.Taken together,EMR-dB was a feasible and safe option for the treatment of small rectal NETs.

FGF信号通路在内耳发育调控和毛细胞再生中的作用

内耳是感受听觉和平衡觉的复杂器官。在内耳发育过程中,成纤维生长因子(fibroblast growth factor,FGF)信号通路参与了听基板的诱导、螺旋神经节(statoacoustic ganglion,SAG)的发育以及Corti器感觉上皮的分化。FGF信号开启了内耳早期发育的基因调控网络,诱导前基板区域以及听基板的形成。正常表达的FGF信号分子可促进听囊腹侧成神经细胞的特化,但成熟SAG神经元释放的过量FGF5可抑制此过程,形成负反馈环路使SAG在稳定状态下发育。FGF20在Notch信号通路的调控下参与了前感觉上皮区域向毛细胞和支持细胞的分化过程,而内毛细胞分泌的FGF8可调控局部支持细胞分化为柱细胞。人类FGF信号通路异常可导致多种耳聋相关遗传病。此外,FGF信号通路在低等脊椎动物毛细胞自发再生以及干细胞向内耳毛细胞诱导过程中都起到了关键作用。本文综述了FGF信号通路在内耳发育调控以及毛细胞再生中的作用及其相关研究进展,以期为毛细胞再生中FGF信号通路调控机制的阐明奠定理论基础。

Effect of resveratrol on Treg/Th17 signaling and ulcerative colitis treatment in mice

AIM: To determine the therapeutic efficacy of resveratrol on ulcerative colitis (UC) and its underlying mechanisms. METHODS: The mouse UC model was developed using 5% dextran sulfate sodium. Mice were randomly divided into four groups: normal control, UC model group, resveratrol low-dose group (RLD; 50 mg/kg per day), and resveratrol high-dose group (RHD; 100 mg/kg per day). RESULTS: The results showed that RLD regulates Treg/Th17 balance mainly through reducing the number of Th17 cells, whereas RHD regulates Treg/Th17 balance through both downregulating the number of Th17 cells and upregulating the number of Treg cells. Resveratrol can also regulate the level of plasma and intestinal mucosal cytokines including interleukin (IL)-10, transforming growth factor-beta 1, IL-6, and IL-17. The expressions of hypoxia inducible factor (HIF)-1 alpha, mammalian target of rapamycin (mTOR), and signal transducer and activator of transcription 3 were significantly decreased in the intestinal tissues of mice treated with resveratrol. CONCLUSION: The therapeutic efficacy of resveratrol in UC is dose dependent and closely associated with the regulation of Treg/Th17 balance and the HIF-1 alpha/mTOR signaling pathway.

Berberine prevents stress-induced gut inflammation and visceral hypersensitivity and reduces intestinal motility in rats

BACKGROUND Irritable bowel syndrome (IBS) is a common chronic non-organic disease of the digestive system. Berberine (BBR) has been used to treat patients with IBS, but the underlying therapeutic mechanism is little understood. We believe that BBR achieves its therapeutic effect on IBS by preventing stress intestinal inflammation and visceral hypersensitivity and reducing bowel motility. AIM To test the hypothesis that BBR achieves its therapeutic effect on IBS by preventing subclinical inflammation of the intestinal mucosa and reducing visceral hypersensitivity and intestinal motility. METHODS IBS was induced in rats via water avoidance stress (WAS). qRT-PCR and histological analyses were used to evaluate the levels of cytokines and mucosal inflammation, respectively. Modified ELISA and qRT-PCR were used to evaluate the nuclear factor kappa-B (NF-κB) signal transduction pathway. Colorectal distention test, gastrointestinal transit measurement, Western blot, and qRT-PCR were used to analyze visceral sensitivity, intestinal motility, the expression of Ckit (marker of Cajal mesenchymal cells), and the expression of brain derived neurotrophic factor (BDNF) and its receptor TrkB.RESULTS WAS led to mucosal inflammation, visceral hyperalgesia, and high intestinal motility. Oral administration of BBR inhibited the NF-κB signal transduction pathway, reduced the expression of pro-inflammatory cytokines [interleukin (IL)- 1β, IL-6, interferon-γ, and tumor necrosis factor-α], promoted the expression of anti-inflammatory cytokines (IL-10 and transforming growth factor-β), and improved the terminal ileum tissue inflammation. BBR inhibited the expression of BDNF, TrkB, and C-kit in IBS rats, leading to the reduction of intestinal motility and visceral hypersensitivity. The therapeutic effect of BBR at a high dose (100 mg/kg) was superior to than that of the low-dose (25 mg/kg) group. CONCLUSION BBR reduces intestinal mucosal inflammation by inhibiting the intestinal NF-κB signal pathway in the IBS rats. BBR reduces the expression of BDNF, its receptor TrkB, and C-kit. BBR also reduces intestinal motility and visceral sensitivity to achieve its therapeutic effect on IBS.

Pleiotrophin promotes perineural invasion in pancreatic cancer

Perineural invasion(PNI)in pancreatic cancer is an important cause of local recurrence,but little is known about its mechanism.Pleiotrophin(PTN)is an important neurotrophic factor.It is of interest that our recent experimental data showed its involvement in PNI of pancreatic cancer.PTN strongly presents in the cytoplasm of pancreatic cancer cells,and high expression of PTN and its receptor may contribute to the high PNI of pancreatic cancer.Correspondingly,PNI is prone to happen in PTN-positive tumors.We thus hypothesize that,as a neurite growth-promoting factor,PTN may promote PNI in pancreatic cancer.PTN is released at the time of tumor cell necrosis,and binds with its highaffinity receptor,N-syndecan on pancreatic nerves,to promote neural growth in pancreatic cancer.Furthermore,neural destruction leads to a distorted neural homeostasis.Neurons and Schwann cells produce more N-syndecan in an effort to repair the pancreatic nerves.However,the abundance of N-syndecan attracts further PTN-positive cancer cells to the site of injury,creating a vicious cycle.Ultimately,increased PTN and N-syndecan levels,due to the continuous nerve injury,may promote cancer invasion and propagation along the neural structures.Therefore,it is meaningful to discuss the relationship between PTN/N-syndecan signaling and PNI in pancreatic cancer,which may lead to a better understanding of the mechanism of PNI in pancreatic cancer.

Midkine promotes perineural invasion in human pancreatic cancer

AIM: To investigate midkine (MK) and syndecan-3 protein expression in pancreatic cancer by immunohistochemistry, and to analyze their correlation with clinicopathological features, perineural invasion, and prognosis.

Novel risk scoring system for prediction of pancreatic fistula after pancreaticoduodenectomy

BACKGROUND The available prediction models for clinically relevant postoperative pancreatic fistula (CR-POPF) do not incorporate both preoperative and intraoperative variables. AIM To construct a new risk scoring system for CR-POPF that includes both preoperative and intraoperative factors. METHODS This was a retrospective study of patients who underwent pancreaticoduodenectomy (PD) or pylorus-preserving PD (PPPD) between January 2011 and December 2016 at the First Affiliated Hospital of Soochow University. Patients were divided into a study (01/2011 to 12/2014) or validation (01/2015 to 12/2016) group according to the time of admission. POPF severity was classified into three grades: Biochemical leak (grade A) and CR-POPF (grades B and C). Logistic regression was used to create a predictive scoring system. RESULTS Preoperative serum albumin ≥ 35 g/L [P = 0.032, odds ratio (OR)= 0.92, 95% confidence interval (CI): 0.85-0.99], hard pancreatic texture (P = 0.004, OR = 0.25, 95%CI: 0.10-0.64), pancreatic duct diameter ≥ 3 mm (P = 0.029, OR = 0.50, 95%CI: 0.27-0.93), and intraoperative blood loss ≥ 500 mL (P = 0.006, OR = 1.002, 95%CI:1.001-1.003) were independently associated with CR-POPF. We established a 10-point risk scoring system to predict CR-POPF. The area under the curve was 0.821 (95%CI: 0.736-0.905) and the cut-off value was 3.5. Including drain amylase levels improved the predictive power of the model. CONCLUSION This study established a 10-point scoring system to predict CR-POPF after PD/PPPD using preoperative and intraoperative parameters. Ultimately, this system could be used to distinguish between high- and low-risk populations in order to facilitate timely interventions after PD.

Endoloop ligation after endoscopic mucosal resection using a transparent cap: A novel method to treat small rectal carcinoid tumors

BACKGROUND Local endoscopic resection is an effective method for the treatment of small rectal carcinoid tumors, but remnant tumor at the margin after resection remains to be an issue.AIM To evaluate the efficacy and safety of resection of small rectal carcinoid tumors by endoloop ligation after cap-endoscopic mucosal resection(LC-EMR) using a transparent cap.METHODS Thirty-four patients with rectal carcinoid tumors of less than 10 mm in diameter were treated by LC-EMR(n = 22) or endoscopic submucosal dissection(ESD)(n =12) between January 2016 and December 2017. Demographic data, complete resection rates, pathologically complete resection rates, operation duration, and postoperative complications were collected. All cases were followed for 6 to 30 mo.RESULTS A total of 22 LC-EMR cases and 12 ESD cases were enrolled. The average age was48.18 ± 12.31 and 46.17 ± 12.57 years old, and the tumor size was 7.23 ± 1.63 mm and 7.50 ± 1.38 mm, respectively, for the LC-EMR and ESD groups. Resection time in the ESD group was longer than that in the LC-EMR group(15.67 ± 2.15 min vs 5.91 ± 0.87 min; P < 0.001). All lesions were completely resected at one time. No perforation or delayed bleeding was observed in either group.Pathologically complete resection(P-CR) rate was 86.36%(19/22) and 91.67%(11/12) in the LC-EMR and ESD groups(P = 0.646), respectively. Two of the three cases with a positive margin in the LC-EMR group received transanal endoscopic microsurgery(TEM) and tumor cells were not identified in the postoperative specimens. The other case with a positive margin chose follow-up without further operation. One case with remnant tumor after ESD received further local ligation treatment. Neither local recurrence nor lymph node metastasis was found during the follow-up period.CONCLUSION LC-EMR appears to be an efficient and simple method for the treatment of small rectal carcinoid tumors, which can effectively avoid margin remnant tumors.

Endoscopic papillary balloon intermittent dilatation and endoscopic sphincterotomy for bile duct stones

AIM: To compare the effectiveness and safety of endoscopic papillary balloon intermittent dilatation (EPBID) and endoscopic sphincterotomy (EST) in the treatment of common bile duct stones. METHODS: From March 2011 to May 2012, endoscopic retrograde cholangiopancreatography was performed in 560 patients, 262 with common bile duct stones. A total of 206 patients with common bile duct stones were enrolled in the study and randomized to receive either EPBID with a 10-12 mm dilated balloon or EST (103 patients in each group). For both groups a conventional reticular basket or balloon was used to remove the stones. After the procedure, routine endoscopic nasobiliary drainage was performed. RESULTS: First-time stone removal was successfully performed in 94 patients in the EPBID group (91.3%) and 75 patients in the EST group (72.8%). There was no statistically significant difference in terms of operation time between the two groups. The overall incidence of early complications in the EPBID and EST groups was 2.9% and 13.6%, respectively, with no deaths reported during the course of the study and follow-up. Multiple regression analysis showed that the success rate of stone removal was associated with stone removal method [odds ratio (OR): 5.35; 95%CI: 2.24-12.77; P=0.00], the transverse diameter of the stone (OR: 2.63; 95%CI: 1.19-5.80; P=0.02) and the presence or absence of diverticulum (OR: 2.35; 95%CI: 1.03-5.37; P=0.04). Postoperative pancreatitis was associated with the EST method of stone removal (OR: 5.00; 95%CI: 1.23-20.28; P=0.02) and whether or not pancreatography was performed (OR: 0.10; 95%CI: 0.03-0.35; P=0.00). CONCLUSION: The EPBID group had a higher success rate of stone removal with a lower incidence of pancreatitis compared with the EST group.

Investigation of erosion behavior of 304 stainless steel under solid–liquid jet flow impinging at 30°

This work carried out liquid-solid two-phase jet experiments and simulations to study the erosion behavior of 304 stainless steel at 30° impingement.The single-phase impinging jet was simulated using dense grid by one-way coupling of solid phase due to its dilute distribution.The simulation results agreed well with experiments.It was found that after impinging particle attrition occurred and particles became round with decreasing length-ratio and particle breakage occurred along the "long" direction.Both experiment and simulations found that the erosion generated on the sample could be divided into three regions that were nominated as stagnant region,cutting transition region and wall jet region.Most particle-wall impacts were found to occur in the cutting transition region and the wall jet region.In the cutting transition region,holes and lip-shaped hogbacks were generated in the same direction as the flow imping.In the wall jet region,furrows and grooves were generated.The averaged grooves depth tended to become constant with the progress of impinging and reach the steady state of erosion in the end.In addition,it was found that impinging effect increased erosion and anti-wear rate.

Effect of quadratic pressure gradient term on a one-dimensional moving boundary problem based on modified Darcy's law

A relatively high formation pressure gradient can exist in seepage flow in low-permeable porous media with a threshold pressure gradient, and a significant error may then be caused in the model computation by neglecting the quadratic pressure gradient term in the governing equations. Based on these concerns, in consideration of the quadratic pressure gradient term, a basic moving boundary model is constructed for a one-dimensional seepage flow problem with a threshold pressure gradient. Owing to a strong nonlinearity and the existing moving boundary in the mathematical model, a corresponding numerical solution method is presented. First, a spatial coordinate transformation method is adopted in order to transform the system of partial differential equa- tions with moving boundary conditions into a closed system with fixed boundary conditions; then the solution can be sta- bly numerically obtained by a fully implicit finite-difference method. The validity of the numerical method is verified by a published exact analytical solution. Furthermore, to compare with Darcy＇s flow problem, the exact analytical solution for the case of Darcy＇s flow considering the quadratic pressure gradient term is also derived by an inverse Laplace transform. A comparison of these model solutions leads to the conclu- sion that such moving boundary problems must incorporate the quadratic pressure gradient term in their governing equa- tions; the sensitive effects of the quadratic pressure gradient term tend to diminish, with the dimensionless threshold pres- sure gradient increasing for the one-dimensional problem.

FXR agonist GW4064 alleviates endotoxin-induced hepatic inflammation by repressing macrophage activation

AIM: To examine the effect of farnesoid X receptor (FXR) activation by GW4064 on endotoxin-induced hepatic inflammation in nonalcoholic fatty liver disease (NAFLD) and the underlying mechanism.