Research on the solid particle erosion wear of pipe steel for hydraulic fracturing based on experiments and numerical simulations

Erosion wear is a common failure mode in the oil and gas industry.In the hydraulic fracturing,the fracturing pipes are not only in high-pressure working environment,but also suffer from the impact of the high-speed solid particles in the fracturing fluid.Beneath such complex conditions,the vulnerable components of the pipe system are prone to perforation or even burst accidents,which has become one of the most serious risks at the fracturing site.Unfortunately,it is not yet fully understood the erosion mechanism of pipe steel for hydraulic fracturing.Therefore,this article provides a detailed analysis of the erosion behavior of fracturing pipes under complex working conditions based on experiments and numerical simulations.Firstly,we conducted erosion experiments on AISI 4135 steel for fracturing pipes to investigate the erosion characteristics of the material.The effects of impact angle,flow velocity and applied stress on erosion wear were comprehensively considered.Then a particle impact dynamic model of erosion wear was developed based on the experimental parameters,and the evolution process of particle erosion under different impact angles,impact velocities and applied stress was analyzed.By combining the erosion characteristics,the micro-structure of the eroded area,and the micro-mechanics of erosion damage,the erosion mechanism of pipe steel under fracturing conditions was studied in detail for the first time.Under high-pressure operating conditions,it was demonstrated through experiments and numerical simulations that the size of the micro-defects in the eroded area increased as the applied stress increased,resulting in more severe erosion wear of fracturing pipes.

Efficient extraction of uranium(VI)from aqueous solution by Zr/Ce-UiO-66-NH_(2) modified by dual strategies of bimetallization and amination

We modified Zr/Ce-UiO-66-NH_(2) using dual bimetallization and amination strategies to efficiently extract uranium from water resources.XRD,FTIR,and XPS indicated the successful alteration of material amination.Moreover,the metal Zr was partially replaced by Ce in Zr-oxygen atom clusters in Zr/Ce-UiO-66-NH_(2).It possessed commendable structural stability in acidic and alkaline solutions.Irrespective of whether it was submerged in a 6 M strong acid or in a 0.5M strong base solution,the structural integrity of Zr/Ce-UiO-66-NH_(2) remained unaffected.Batch experiments at pH=6.0 revealed that uranium adsorption by Zr/Ce-UiO-66-NH_(2) reached 376.8 mg g^(−1) and 611.33 mg g^(−1) at 298 K and 328 K,respectively.These values are much better than those obtained using bimetallic-modified Zr/Ce-UiO-66 or amine-functionalized UiO-66-NH_(2).After five consecutive sorption and desorption cycles,the material retained a uranium removal rate of more than 80%,proving its excellent regenerative properties.Kinetic modeling of U(VI)adsorption on Zr/Ce-UiO-66-NH_(2) implied that chemisorption dominated the rapid uranium sorption rate.We propose potential adsorption mechanisms involving three interactions:inner-sphere surface complexation,chemisorption,and electrostatic interactions.This study shows that the dual strategies of bimetallization and amination can effectively enhance U(VI)extraction from water.This approach has potential applications for the structural design of uranium adsorbents.

MicroRNA-145-3p在先天性巨结肠中的作用及机制研究

目的探讨micro RNA-145-3p(miR-145-3p)在先天性巨结肠(HD)中的表达及其发挥作用的可能分子机制。方法选取2013年2月-2018年6月南方医科大学珠江医院40例HD病变段肠管(HD病变肠管组)及40例正常肠管(正常肠管组)组织标本。采用qRT-PCR检测组织标本miR-145-3p相对表达量。过表达细胞miR-145-3p后,CCK-8法检测细胞的增殖情况;Transwell检测细胞迁移情况;双荧光素酶报告基因实验、Western blotting及免疫组织化学染色明确miR-145-3p对靶基因GDNF的影响。结果HD病变肠管组miR-145-3p相对表达量高于正常肠管组(P<0.05)。过表达细胞miR-145-3p后,细胞增殖能力下降(P<0.05),细胞迁移能力降低(P<0.05);靶基因预测软件筛选出GDNF是miR-145-3p的潜在靶点;双荧光素酶报告基因实验证实,miR-145-3p可以与GDNF的3’-UTR结合(P<0.05);Western blotting检测证实,miR-145-3p可使SH-SY5Y细胞的GDNF蛋白相对表达量降低(P<0.05);而免疫组织化学染色证实,GDNF在miR-145-3p高表达的HD组织标本中存在高频低表达。结论miR-145-3p可以抑制神经母细胞的增殖及迁移,是一个重要的HD分子标志物,其作用机制可能与抑制GDNF蛋白表达有关。

联合运输中驱动液压系统群可靠性分析与计算

为保证联合运输安全,对两车联合运输的驱动液压系统组进行了研究。同步控制是安全运输的关键,对驱动液压系统群和控制系统的可靠性要求很高。因此,必须对驱动液压系统群的寿命预测和可靠性增长进行研究。两车联合运输的驱动液压系统群的可靠性为对象进行了研究,首先对某运输车辆的可靠性模型进行了研究,建立了运输车传动系统的可靠性框图模型;并在此基础上建立了相应的可靠性数学模型;经过MATLAB软件进行计算,得到了驱动液压系统群的可靠性曲线和可靠度。并针对工程实践中的驱动不同步问题建立了驱动液压系统群的故障树模型,对故障树进行了定量和定性分析,最终找出了驱动液压系统的薄弱环节。进而可以在设计过程中就考虑到预防故障的产生,提高系统的设计水平,该方法可有效提高联合运输液压系统群可靠性。

Cystatin C is a biomarker for predicting acute kidney injury in patients with acute-on-chronic liver failure

AIM:To investigate serum cystatin C level as an early biomarker for predicting acute kidney injury(AKI)in patients with acute-on-chronic liver failure(ACLF).METHODS:Fifty-six consecutive patients with hepatitis B virus-related ACLF who had normal serum creatinine(Cr)level(<1.2 mg/dL in men,or<1.1 mg/dL in women)were enrolled in the Liver Failure Treatment and Research Center of Beijing 302 Hospital between August 2011 and October 2012.Thirty patients with chronic hepatitis B(CHB)and 30 healthy controls in the same study period were also included.Measurement of serum cystatin C(CysC)was performed by a particle-enhanced immunonephelometry assay using the BN Prospec nephelometer system.The ACLF patients were followed during their hospitalization period.RESULTS:In the ACLF group,serum level of CysC was 1.1±0.4 mg/L,which was significantly higher(P<0.01)than those in the healthy controls(0.6±0.3mg/L)and CHB patients(0.7±0.2 mg/L).During the hospitalization period,eight ACLF patients developed AKI.Logistic regression analysis indicated that CysC level was an independent risk factor for AKI development(odds ratio=1.8;95%CI:1.4-2.3,P=0.021).The cutoff value of serum CysC for prediction of AKI in ACLF patients was 1.21 mg/L.The baseline CysC-based estimated glomerular filtration rate(eGFR CysC)was significantly lower than the creatinine-based eGFR(eGFR CG and eGFR MDRD)in ACLF patients with AKI,suggesting that baseline eGFR CysC represented early renal function in ACLF patients while the Cr levels were still within the normal ranges.CONCLUSION:Serum CysC provides early prediction of renal dysfunction in ACLF patients with a normal serum Cr level.

Fast track clinical pathway implications in esophagogastrectomy

AIM： To investigate the feasibility of fast track clinica pathway for esophageal tumor resections. METHODS： One hundred and fourteen patients with esophageal carcinoma who underwent esophagogastrectomy from January 2006 to October 2007 in our department were studied. Fast track clinical pathway included analgesia control, fluid infusion volume control, early ambulation and enteral nutrition. Nasogastric tube was removed 3 d after operation and chest tube was removed 4 d after operation as a routine, and full liquid diet 5 d after operation. RESULTS： Among 114 patients （84 men and 30 women）, 26 patients underwent fast track surgery, including 17 patients over 65 years old and 9 under 65 （P = 0.014）; 18 patients who had preoperative complications could not bear fast track surgery （P 〈 0.001）. No significant differences in tolerance of fast track surgery were attributed to differences in gender, differentiated degree or stage of tumor, pathological type of tumor, or operative incision. The median length of hospital stay was 7 d （5-28 d）, 4% patients were readmitted to hospital within 30 d of discharge. Three patients died and postoperative mortality was 2.6%. All 3 patients had no determinacy to fast track surgery approach.CONCLUSION： The majority of patients with esophageal carcinoma can tolerate fast track surgery. Patients younger than 65 or who have no preoperative diseases have the best results. Median length of hospital stay has been reduced to 7 d.

Padua评分预测重症患者静脉血栓栓塞症风险的价值

目的探讨Padua评分对预测重症患者发生静脉血栓栓塞症(VTE)风险的有效性。方法采用病例对照的方法进行回顾性研究,选取华北理工大学附属医院重症医学科(ICU)患者中确诊的78例VTE患者(VTE组)及同时期同科室随机抽取的96例未患VTE患者(非VTE组)。依据Padua评分对两组患者进行评分和危险分层。比较两组评分结果以及危险等级之间的关系,采用多因素Logistic回归模型分析危险因素与VTE发生之间的关系。结果 VTE组Padua评分与非VTE组比较,差异有统计学意义(P <0.05),VTE组高于非VTE组,高评分等级组患者发生VTE的风险是低评分等级组的7.66倍。以ICU住院患者的相关因素作为自变量进行Logistic回归分析发现:卧床≥3 d是ICU住院患者发生VTE的最高级别的危险因素。结论 Pauda评分可较好地评估ICU患者VTE发病的危险程度。

Study of evaluation method for the overseas oil and gas investment based on risk compensation

The overseas oil and gas investment evaluation is one of the core tasks in overseas investment of oil and gas companies,among which risk evaluation and benefit evaluation are the most important.This paper sets forth transmission paths of risk factors to the investment benefit by identifying 14 overseas oil and gas investment risks in four categories.On the basis of the concept of risk compensation,different compensation mechanisms specific to each risk are designed.The risk and benefit are integrated objectively to develop a comprehensive evaluation model by correcting the recoverable reserve,adjusting benefit evaluation parameters such as investments on exploration and development,and compensating for the changes in risk factors with time through dynamic discount rate.Moreover,two cases studies,namely the evaluations of Project A in Sudan and comparison among Blocks A–G,are used to describe usage method and applicable scope of such evaluation model,respectively.According to the results,oil price is a key influencing factor for enterprise internal risk and industrial risk.Risk compensation reduces comprehensive benefit of overseas oil and gas investment and undermines the investment feasibility and priority of blocks.The research findings of this paper are free from the effects of some subject factors and avoid multi-objective decision making,and also avoid the undesired repeated calculation of risk factors.

MicroRNAs and long non-coding RNAs in liver surgery:Diagnostic and therapeutic merits

Background:Hepatectomy and liver transplantation(LT)are the two most commonly performed surgical procedures for various hepatic lesions.micro RNA(mi RNA)and long non-coding RNA(lnc RNA)have been gradually unveiled their roles as either biomarkers for early diagnosis or potentially therapeutic tools to manipulate gene expression in many disease entities.This review aimed to discuss the effects of mi RNA or lnc RNA in the hepatectomy and LT fields.Data sources:We did a literature search from 1990 through January 2018 to summarize the currently available evidence with respect to the effects of mi RNA and lnc RNA in liver regeneration after partial hepatectomy,as well as their involvement in several key issues related to LT,including ischemia-reperfusion injury,allograft rejection,tolerance,recurrence of original hepatic malignancies,etc.Results:Certain mi RNAs and lnc RNAs are actively involved in the regulation of various aspects of liver resection and transplantation.During the process of liver regeneration after hepatectomy,the expression of mi RNAs and lnc RNAs shows dynamic changes.Conclusions:It is now clear that mi RNAs and lnc RNAs orchestrate in various aspects of the pathophysiological process of LT and hepatectomy.Better understanding of the underlying mechanism and future clinical trials may strengthen their positions as either biomarkers or potential therapeutic targets in the management of complications after liver surgery.

Effect of mold rotation on the bifilar electroslag remelting process

A novel electroslag furnace with a rotating mold was fabricated, and the effects of mold rotational speed on the electroslag remelting process were investigated. The results showed that the chemical element distribution in ingots became uniform and that their compact density increased when the mold rotational speed was increased from 0 to 28 r/min. These results were attributed to a reasonable mold speed, which resulted in a uniform temperature in the slag pool and scattered the metal droplets randomly in the metal pool. However, an excessive rotational speed caused deterioration of the solidification structure. When the mold rotational speeds was increased from 0 to 28 r/min, the size of Al2O3 inclusions in the electroslag ingot decreased from 4.4 to 1.9 μm. But the excessive mold rotational speed would decrease the ability of the electroslag remelting to remove the inclusions. The remelting speed gradually increased, which resulted in reduced power consumption with increasing mold rotational speed. This effect was attributed to accelerated heat exchange between the consumable electrode and the molten slag, which resulted from mold rotation. Nevertheless, when the rotational speed reached 28 r/min, the remelting speed did not change because of limitations of metal heat conduction. Mold rotation also improved the surface quality of the ingots by promoting a uniform temperature distribution in the slag pool.

Oncogenic Wnt3a is a promising sensitive biomarker for monitoring hepatocarcinogenesis

Background:The effective treatment for hepatocellular carcinoma(HCC)depends on early diagnosis.Previously,the abnormal expression of Wnt3a as the key signaling molecule in the Wnt/β-catenin pathway was found in HCC cells and could be released into the circulation.In this study,we used rat model of hepatocarcinogenesis to dynamically investigate the alteration of oncogenic Wnt3a and to explore its early monitor value for HCC.Methods:Sprague-Dawley rats(SD)were fed with diet 2-fluorenylacetamide(2-FAA,0.05%)for inducing hepatocarcinogenesis,and grouped based on liver morphological alteration by Hematoxylin&Eosin(H&E)staining;rats fed with normal chow were used as normal control(NC).Total RNA and protein were purified from rat livers.Differently expressed genes(DEGs)or Wnt3a m RNA,cellular distribution,and Wnt3a protein levels were analyzed by whole genome microarray with signal logarithm ratio(SLR log 2 cy5/cy3),immunohistochemistry,and enzyme-linked immunosorbent assay,respectively.Results:Models of rat hepatocarcinogenesis were successfully established based on liver histopathological H&E staining.Rats were divided into the cell degeneration(r Deg),precancerosis(r Pre-C)and HCC(r HCC)groups.Total numbers of the up-and down-regulated DEGs with SLR≥8 were 55 and 48 in the r Deg group,268 and 57 in the r Pre-C group,and 312 and 201 in the r HCC group,respectively.Significantly altered genes were involved in cell proliferation,signal transduction,tumor metastasis,and apoptosis.Compared with the NC group,Wnt3a m RNA was increased by 4.6 folds(P<0.001)in the r Deg group,7.4 folds(P<0.001)in the r Pre-C group,and 10.4 folds(P<0.001)in the r HCC group;the positive rates of liver Wnt3a were 66.7%(P=0.001)in the r Deg group,100%(P<0.001)in the r Pre-C group,and 100%(P<0.001)in the r HCC group,respectively.Also,there were significant differences of liver Wnt3a(P<0.001)or serum Wnt3a(P<0.001)among different groups.Conclusions:Overexpression of Wnt3a was associated with rat hepatocarcinogenesis and it should be expected to be a promising monitoring biomarker for HCC occurrence at early stage.

Plasma preparation and low-temperature sintering of spherical TiC –Fe composite powder

A spherical Fe matrix composite powder containing a high volume fraction （82vo1%） of fine TiC reinforcement was produced using a novel process combining in situ synthesis and plasma techniques. The composite powder exhibited good sphericity and a dense structure, and the fine sub-micron TiC particles were homogeneously distributed in the α-Fe matrix. A TiC-Fe cermet was prepared from the as-prepared spherical composite powder using powder metallurgy at a low sintering temperature; the product exhibited a hardness of HRA 88.5 and a flexural strength of 1360 MPa. The grain size of the fine-grained TiC and special surface structure of the spherical powder played the key roles in the fabrication process.

Microstructure and properties of hydrophobic films derived from Fe-W amorphous alloy

Amorphous metals are totally different from crystalline metals in regard to atom arrangement. Amorphous metals do not have grain boundaries and weak spots that crystalline materials contain, making them more resistant to wear and corrosion. In this study, amorphous Fe-W alloy films were first prepared by an electroplating method and were then made hydrophobic by modification with a water repellent （heptadecafluoro-1,1,2,2-tetradecyl） trimethoxysilane. Hierarchical micro-nano structures can be obtained by slightly oxidizing the as-deposited alloy, accompanied by phase transformation from amorphous to crystalline during heat treatment. The mi-cro-nano structures can trap air to form an extremely thin cushion of air between the water and the film, which is critical to producing hydrophobicity in the film. Results show that the average values of capacitance, roughness factor, and impedance for specific surface areas of a 600°C heat-treated sample are greater than those of a sample treated at 500°C. Importantly, the coating can be fabricated on various metal substrates to act as a corrosion retardant.

Effect of ultrasonic power introduced by a mold copper plate on the solidification process

An electroslag furnace with ultrasonic vibration introduced by a mold copper plate was designed. The effects of ultrasonic power on the element distribution and compactness in electroslag remelting （ESR） ingots were studied, and the mechanism of ultrasonic assistance was analyzed in cold experiments. In the results, silicon, manganese and chromium are uniformly distributed at an ultrasonic power of 300-750 W. The absence of ultrasonic or higher ultrasonic power is not conducive to the uniformity of alloying elements. Carbon demon- strates a highly uneven distribution at 300 W, gradually reaches the uniform distribution as the ultrasonic power further increases, and shows the poor distribution at 1000 W. The compactness of ESR ingots gradually increases with increasing ultrasonic power and reaches the uni- form distribution at 500 W. A further increase in ultrasonic power does not improve the compactness. Introducing ultrasonic vibrations by a mold copper plate can improve the solidification quality; however, an appropriate ultrasonic power level should be determined.

Primary ascending colon cancer accompanying skip metastases in left shoulder skin and left neck lymph node: A case report

BACKGROUND Lymph node skip metastases are common in lung,breast,and thyroid cancer patients,but are rare in colon cancer patients.Specifically,lymph node skip metastases occur in 1%-3%of colon cancer patients.Previous reports have demonstrated colon cancer skip metastases involving the retropancreatic and portocaval lymph nodes and Virchow's node;however,reports involving skip metastases into the left neck lymph nodes and left shoulder skin are extremely rare,as are related reports of clinical treatment and prognosis.CASE SUMMARY A 44-year-old Chinese man was admitted to the hospital for evaluation of persistent shoulder pain for 3 d and a cutaneous mass(3.0 cm×2.0 cm)on the left shoulder.The left shoulder cutaneous mass was excised and bisected,revealing tissues with a fish-like appearance.The pathologic diagnosis of the cutaneous mass suggested a signature[CDX-2(++),CK20(++),Ki-67(+)>50%]of infiltrating or metastatic colorectal adenocarcinoma.An enhanced computed tomography scan of the abdomen revealed chronic appendicitis with fecal stone formation,cecal edema,and a pelvic effusion.A colonoscopy revealed a cauliflower-like mass within the ascending colon area that involved the lumen.The surface of the ascending colon mass was eroded and bleeding;a biopsy was performed.The pathologic diagnosis of the colonoscopy biopsy was an ascending colon mucinous adenocarcinoma.The patient underwent a laparoscopic radical resection of the right colon based on the pathological diagnosis.The tumor was 5.0 cm×4.5 cm×1.8 cm in size and infiltrated the entire thickness of the intestinal wall with vascular tumor thrombi.No nerve tissue involvement was noted.The ileum and colon resection margins were negative.The postoperative pathologic analysis revealed non-metastatic involvement of ileocecal,pericolic,or peri-ileal lymph nodes.The postoperative medical examination revealed palpably enlarged lymph nodes in the left neck,and the following color Doppler ultrasound examination of the neck confirmed enlarged lymph nodes in the left neck.After surgical resection and pathologic diagnosis,a common pathologic signature consistent with resected cutaneous mass and right colon was identified,suggesting skip metastasis of left cervical lymph nodes.The patient was then treated with eight courses of chemotherapy and under followup evaluations for 4 years;currently,no tumor recurrences or metastases have been noted.CONCLUSION We report an abnormal skip metastasis involving the left shoulder skin and left neck lymph node in a patient with ascending colon adenocarcinoma.Specifically,we observed non-metastatic involvement of the lymph nodes around the tumor site but with metastases to the cervical lymph nodes.The standard surgical operations were performed to resect the cutaneous mass,tumor tissue,and cervical lymph nodes,followed by chemotherapy for eight courses.The patient is healthy with no tumor recurrences or metastases for 4 years.This clinical case will contribute to future research about the abnormal skip metastasis in colon cancers and a better clinical treatment design.

Selective Se doping of NiFe_(2)O_(4) on an active NiOOH scaffold for efficient and robust water oxidation

There remains a challenge in designing electrocatalysts for water oxidation to create highly efficient catalytic sites for the oxygen evolution reaction(OER)while maintaining their robustness at large outputs.Herein,an etching-assisted synthesis approach was developed to integrate highly active NiFe2O4 nanoparticles with a robust and active NiOOH scaffold directly on commercial stainless steel.A precise selenization strategy was then introduced to achieve selective Se doping of NiFe2O4 to further enhance its intrinsic OER activity while maintaining a three-dimensional NiOOH nanosheet array as a robust scaffold for prompt mass transfer and gas evolution.The resulting NiFe2O4-xSex/NiOOH electrode exhibited superior electrocatalytic activity with low overpotentials of 153 and 259 mV to deliver benchmark current densities of 10 and 500 mA cm^(−2),respectively.More importantly,the catalyst exhibited remarkable durability at a stable current output of 100 mA cm^(−2)for hundreds of hours.These findings may open up opportunities for exploring efficient and robust electrocatalysts for scalable hydrogen production with practical materials.

Relationship between adjustment of low water level and utilization of water depth in Shashi Reach in middle Yangtze River

Hydrological,sediment,and bathymetric data of the Shashi Reach in the middle Yangtze River for the period of 1975-2018 were collected,and the characteristics of low water level changes and their impacts on utilization of water depth for navigation were investigated.The results showed that,during the study period,the Shashi Reach riverbed was significantly scoured and incised,with cross-sectional profiles showing overall narrowing and deepening.This indicated a strong potential to improve the water depth of the channel.The analysis of the temporal variation of in-channel topographical features showed that the Taipingkou diara underwent siltation and erosion,with its head gradually scoured and relocated downstream after 2008,and the Sanbatan diara continued to shrink and migrate leftwards.Low water levels with the same flow rate over the study period decreased.For instance,from 2003 to 2020,the water level at the Shashi hydrological station decreased to 1.37 m with a flow rate of 6000 m^(3)/s.Furthermore,the designed minimum navigable water level of the Shashi Reach was approximately 2.11m lower than the recommended level.In terms of utilization of the channel water depth,continuous scouring of the river channel is expected to result in a reduction in discharge at the Taipingkou mouth,which will improve the water depth conditions of the channel during the dry season in the Shashi Reach.With several channel regulation projects,the 3.5-m depth of the Shashi Reach would basically be unobstructed.This promotes utilization of the shipping route from the Taipingkou south branch to the Sanbatan north branch as the main navigation channel during the dry season.Considering the factors of current water depth and the clear width limitation of the navigation hole at the Jingzhou Yangtze River Bridge,this route can still be favored as the main navigation channel with a 4.5-m depth during the dry season.

Fe-doped ZnS film fabricated by electron beam evaporation and its application as saturable absorber for Er:ZBLAN fiber laser

High-quality Fe-doped Zn S films have been fabricated by electron beam evaporation.After the doping,the fabricated films still maintain the preferential crystalline orientation and phase purity of the host Zn S.According to the observation of surface morphology,the root mean-square roughness of the samples increases slightly with the increase of doping content.All of the prepared samples are in cubic zinc blende structure of Zn S.Transmission spectrum confirms a more obvious dip near 3μm with higher dopant concentration and it can be attributed to the typical^(5)E→^(5)T_(2)transition of Fe^(2+).Fe-doped Zn S film is also successfully used for Q-switched Er:ZBLAN fiber laser.

Clinicopathological characterization of ten patients with primary malignant melanoma of the esophagus and literature review

BACKGROUND Primary malignant melanoma of the esophagus(PMME) is a rare malignant disease and has not been well characterized in terms of clinicopathology and survival.AIM To investigate the clinical features and survival factors in Chinese patients with PMME.METHODS The clinicopathological findings of ten cases with PMME treated at Henan Provincial People’s Hospital were summarized. Moreover, the English-and Chinese-language literature that focused on Chinese patients with PMME from 1980 to September 2021 was reviewed and analyzed. Univariate and multivariate analyses were employed to investigate the clinicopathologic factors that might be associated with survival.RESULTS A total of 290 Chinese patients with PMME, including ten from our hospital and 280 from the literature were enrolled in the present study. Only about half of the patients(55.8%) were accurately diagnosed before surgery. Additionally, 91.1% of the patients received esophagectomy, and 88 patients(36.5%) received adjuvant therapy after surgery. The frequency of lymph node metastasis(LNM) was 51.2%(107/209), and LNM had a positive rate of 45.3% even when the tumor was confined to the submucosal layer. The risk of LNM increased significantly with the p T stage [P < 0.001, odds ratio(OR): 2.47, 95% confidence interval(CI): 1.72-3.56] and larger tumor size(P = 0.006, OR: 1.21, 95%CI: 1.05-1.38). The median overall survival(OS) was 11.0 mo(range: 1-204 mo). The multivariate Cox analysis showed both the p T stage [P = 0.005, hazard ratio(HR): 1.70, 95%CI: 1.17-2.47] and LNM(P = 0.009, HR: 1.78, 95%CI: 1.15-2.74) were independent prognostic factors for OS. The median disease-free survival(DFS) was 5.3 mo(range: 0.8-114.1 mo). The multivariate analysis indicated that only the advanced p T stage(P = 0.02, HR: 1.93, 95%CI: 1.09-3.42) was a significant independent indicator of poor RFS in patients with PMME.CONCLUSION The correct diagnosis of PMME before surgery is low, and physicians should pay more attention to avoid a misdiagnosis or missed diagnosis. Extended lymph node dissection should be emphasized in surgery for PMME even though the tumor is confined to the submucosal layer. Both the LNM and p T stage are independent prognosis factors for OS, and the p T stage is the prognosis factor for DFS in patients with PMME.

Application of double-layer Ether CAT and optical fiber interlock net in short circuit protection

The selectivity of short circuit protection of high voltage lines in coal mines cannot be realized by existing protection systems. To solve this problem, a scheme based on double layer Ether CAT and optical fiber interlock net was proposed. The system is mainly composed of double layer Ether CAT, optical fiber interlock net, ground monitoring station, underground control stations and integrated protection devices with Ether CAT communication interface and interlock interface. Double layer Ether CAT and optical fiber interlock net cooperate with each other, when one is interrupted, the other net carl realize selectivity of short circuit protection independently, Results of test show that the system can achieve selectivity of short circuit protection reliably, determine the fault location quickly, shorten troubleshooting time and improve safety and reliability of the power network in coal mines.