Experimental study of the effects of a multistage pore-throat structure on the seepage characteristics of sandstones in the Beibuwan Basin:Insights into the flooding mode

To investigate the relationship between grain sizes, seepage capacity, and oil-displacement efficiency in the Liushagang Formation of the Beibuwan Basin, this study identifies the multistage pore-throat structure as a crucial factor through a comparison of oil displacement in microscopic pore-throat experiments. The two-phase flow evaluation method based on the Li-Horne model is utilized to effectively characterize and quantify the seepage characteristics of different reservoirs, closely relating them to the distribution of microscopic pores and throats. It is observed that conglomerate sandstones at different stages exhibit significant heterogeneity and noticeable differences in seepage capacity, highlighting the crucial role played by certain large pore throats in determining seepage capacity and oil displacement efficiency. Furthermore, it was found that the displacement effects of conglomeratic sandstones with strong heterogeneity were inferior to those of conventional homogeneous sandstone, as evidenced by multiple displacement experiments conducted on core samples with varying granularities and flooding systems. Subsequently, core-based experiments on associated gas flooding after water flooding were conducted to address the challenge of achieving satisfactory results in a single displacement mode for reservoirs with significant heterogeneity. The results indicate that the oil recovery rates for associated gas flooding after water flooding increased by 7.3%-16.4% compared with water flooding alone at a gas-oil ratio of approximately 7000 m^(3)/m^(3). Therefore, considering the advantages of gas flooding in terms of seepage capacity, oil exchange ratio, and the potential for two-phase production, gas flooding is recommended as an energy supplement mode for homogeneous reservoirs in the presence of sufficient gas source and appropriate tectonic angle. On the other hand, associated gas flooding after water flooding is suggested to achieve a more favorable development effect compared to a single mode of energy supplementation for strongly heterogeneous sandstone reservoirs.

内镜黏膜下剥离术衍生技术内镜黏膜下挖除术在消化道神经内分泌肿瘤中的应用

目的探讨内镜黏膜下剥离术(ESD)衍生技术内镜黏膜下挖除术(ESE)治疗消化道神经内分泌肿瘤(NET)的安全性及其疗效。方法采用ESE方法对23例消化道NET进行治疗,术后标本送病理检查,记录不良反应发生情况及疗效,随访肿瘤复发及转移情况。结果肿瘤直径0.4~3.0 cm,中位大小1.0 cm,均一次性完整剥离切除,ESE手术时间(自黏膜下注射至完整剥离病变)20~75 min,中位手术时间30 min,1例出现迟发性出血,1例因肿瘤侵犯固有肌层主动穿孔全层切除。术后23例病理诊断为NET,其中G1级21例、G2级2例,3例胃NET中,1型2例,2型1例,基底和切缘均未见病变累及。中位随访28个月,无1例出现肿瘤复发和转移。结论 ESE治疗消化道NET具有较好的安全性和疗效,值得在临床上推广应用。

Multiple advanced surgical techniques to treat acquired seminal duct obstruction

The aim of this study was to evaluate the outcomes of multiple advanced surgical treatments （i.e. microsurgery, laparoscopic surgery and endoscopic surgery）for acquired obstructive azoospermia. We analyzed the surgical outcomes of 51 patients with suspected acquired obstructive azoospermia consecutively who enrolled at our center between January 2009 and May 2013. Modified vasoepididymostomy, laparoscopically assisted vasovasostomy and transurethral incision of the ejaculatory duct with holmium laser were chosen and performed based on the different obstruction sites. The mean postoperative follow-up time was 22 months （range： 9 months to 52 months）. Semen analyses were initiated at four postoperative weeks, followed by trimonthly （months 3, 6, 9 and 12） semen analyses, until no sperm was found at 12 months or until pregnancy was achieved. Patency was defined as 〉10,000 sperm m1-1 of semen. The obstruction sites, postoperative patency and natural pregnancy rate were recorded. Of 51 patients, 47 underwent bilateral or unilateral surgical reconstruction; the other four patients were unable to be treated with surgical reconstruction because of pelvic vas or intratesticular tubules obstruction. The reconstruction rate was 92.2% （47/51）, and the patency rate and natural pregnancy rate were 89.4% （42/47） and 38.1% （16/42）, respectively. No severe complications were observed. Using multiple advanced surgical techniques, more extensive range of seminal duct obstruction was accessible and correctable; thus, a favorable patency and pregnancy rate can be achieved.

Long-term prognosis in patients continuing taking antithrombotics after peptic ulcer bleeding

AIM To investigate the long-term prognosis in peptic ulcer patients continuing taking antithrombotics after ulcer bleeding, and to determine the risk factors that influence the prognosis. METHODS All clinical data of peptic ulcer patients treated from January 1, 2009 to January 1, 2014 were retrospectively collected and analyzed. Patients were divided into either a continuing group to continue taking antithrombotic drugs after ulcer bleeding or a discontinuing group to discontinue antithrombotic drugs. The primary outcome of follow-up in peptic ulcer bleeding patients was recurrent bleeding, and secondary outcome was death or acute cardiovascular disease occurrence. The final date of follow-up was December 31, 2014. Basic demographic data, complications, and disease classifications were analyzed and compared by t- or χ2-test. The number of patients that achieved various outcomes was counted and analyzed statistically. A survival curve was drawn using the Kaplan-Meier method, and the differencewas compared using the log-rank test. COX regression multivariate analysis was applied to analyze risk factors for the prognosis of peptic ulcer patients. RESULTS A total of 167 patients were enrolled into this study. As for the baseline information, differences in age, smoking, alcohol abuse, and acute cardiovascular diseases were statistically significant between the continuing and discontinuing groups(70.8 ± 11.4 vs 62.4 ± 12.0, P < 0.001; 8(8.2%) vs 15(21.7%), P < 0.05; 65(66.3%) vs 13(18.8%), P < 0.001). At the end of the study, 18 patients had recurrent bleeding and three patients died or had acute cardiovascular disease in the continuing group, while four patients had recurrent bleeding and 15 patients died or had acute cardiovascular disease in the discontinuing group. The differences in these results were statistically significant(P = 0.022, P = 0.000). The Kaplan-Meier survival curve indicated that the incidence of recurrent bleeding was higher in patients in the continuing group, and the risk of death and developing acute cardiovascular disease was higher in patients in the discontinuing group(log-rank test, P = 0.000 for both). Furthermore, COX regression multivariate analysis revealed that the hazard ratio(HR) for recurrent bleeding was 2.986(95%CI: 067-8.356, P = 0.015) in the continuing group, while HR for death or acute cardiovascular disease was 5.216(95%CI: 1.035-26.278, P = 0.028).CONCLUSION After the occurrence of peptic ulcer bleeding, continuing antithrombotics increases the risk of recurrent bleeding events, while discontinuing antithrombotics would increase the risk of death and developing cardiovascular disease. This suggests that clinicians should comprehensively consider the use of antithrombotics after peptic ulcer bleeding.

Research on the mechanism of the two-dimensional ultrasonic surface burnishing process to enhance the wear resistance for aluminum alloy

The gradient nanostructure is machined on the aluminum(Al)alloy by the two-dimensional ultrasonic surface burnishing process(2D-USBP).The mechanism of why the gradient nanostructure enhances wear resistance is investigated.The mechanical properties and microstructure characterization for the gradient nanostructure are performed by operating a nanoindenter,transmission electron microscopy(TEM),and electron backscattered diffraction(EBSD).Dry wear tests are performed on the samples before and after machining to evaluate the wear resistance and mechanisms.The effect of the gradient nanostructure on the wear resistance is explored by developing the crystal plasticity(CP)finite element and molecular dynamics(MD)models.The characterization results show that the 2D-USBP sample prepared a gradient structure of~600μm thick on the aluminum surface,increasing the surface hardness from 1.13 to 1.71 GPa and reducing the elastic modulus from 78.84 to 70.14 GPa.The optimization of the surface microstructure and the increase of the mechanical properties effectively enhance the wear resistance of the sample,with 41.20%,39.07%,and 54.58% of the wear scar areas for the 2D-USBP treated samples to the original samples under 5,10,and 15 N loads,respectively.The gradient nanostructure hinders the slip of dislocations inside the sample during the wear process and reduces the size and scope of plastic deformation;meanwhile,the resistance to deformation,adhesion,and crack initiation and propagation of the sample surface is improved,resulting in enhanced wear resistance.

New Developments in Treatments of Tibial Plateau Fractures

Tibial plateau fractures account for 1.66–2.0% of all fractures in adults and about 8% of fractures in the elderly.[1] Tibial plateau fractures should be considered as complex injuries representing a wide fracture spectrum： soft-tissue compromise, neurovascular damage, compartment syndrome, and ligament and meniscus tears, which remain a big challenge, even for experienced orthopedic trauma surgeons. Although the best treatment modality remains controversial, we aimed to present new developments in the treatment of tibial plateau fractures for reference.

Therapeutic effects of herbal formula Huangqisan on metabolic disorders via SREBF1,SCD1 and AMPK signaling pathway

Objective:Metabolic syndrome is a complex medical condition that has become an alarming epidemic,but an effective therapy for this disease is still lacking.The use of the herbal formula Huangqisan(HQS)to treat diabetes is documented in the Chinese medical literature as early as 1117 A.D.;however,its therapeutic effects and underlying mechanisms remain elusive.Methods:To investigate the beneficial effects of HQS on metabolic disorders,high-fat diet-induced obesity(DIO),leptin receptor dysfunction(db/db)and low-density lipoprotein receptor-knockout(LDLR^(-/-))mice were used.Obese mice were treated with either HQS or vehicle.Blood,liver tissue,white fat tissue and brown adipose tissue were harvested at the end of the treatment.Metabolic disease-related parameters were evaluated to test effects of HQS against diabetes,obesity and hyperlipidemia.Aortic arches from LDLR^(-/-)mice were analyzed to investigate the effects of HQS on atherosclerosis.RNA-sequence,quantitative real-time polymerase chain reaction and Western blot were performed to investigate the mechanisms of HQS against metabolic disorder.Results:HQS lowered body weight,fasting blood glucose and serum lipid levels and improved glucose tolerance and insulin sensitivity in DIO mice and db/db mice(P<0.05).HQS also blocked atherosclerotic plaque formation in LDLR^(^(-/-)) mice.HQS suppressed de novo lipid synthesis by reducing the expression of messenger RNA for sterol regulatory element-binding factor 1,stearyl coenzyme A desaturase 1 and fatty acid synthase,and enhancing adenosine 5’-monophosphate-activated protein kinase signaling in both in vivo and in vitro experiments,indicating potential mechanisms for HQS’s activity against diabetes.Conclusion:HQS is effective for reversing metabolic disorder and has the potential to be used as therapy for metabolic syndrome.

Accumulated damage process of thermal sprayed coating under rolling contact by acoustic emission technique

The accumulated damage process of rolling contact fatigue （RCF） of plasma-sprayed coatings was investigated. The influences of surface roughness, loading condition, and stress cycle frequency on the accumulated damage status of the coatings were discussed. A ball-on- disc machine was employed to conduct RCF experiments. Acoustic emission （AE） technique was introduced to monitor thc RCF process of the coatings. AE signal characteristics were investigated to reveal the accumulated damage process. Result showed that the polished coating would resist the asperity contact and remit accumulated damage. The RCF lifetime would then extend. Heavy load would aggravate the accumulated damage status and induce surface fracture. Wear became the main failure mode that reduced the RCF lifetime. Frequent stress cycle would aggravate the accumulated damage status and induce interface fracture. Fatigue then became the main failure mode that also reduced the RCF lifetime.

The importance of laparoscopy in the surgical reconstruction of inguinal vas injury

Dear Editor, We are very interested in the recent paper published by Chen et al.1 because we also have treated patients with iatrogenic vasal injury. We agree with the opinion in this paper that surgical reconstruction of vas injury is more complex than vasectomy reversal.