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24 result(s) for "Dang, Xue‐Yi"
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Conditional survival and recurrence of remnant gastric cancer after surgical resection: A multi‐institutional study
The present study was designed to evaluate the dynamic survival and recurrence of remnant gastric cancer (RGC) after radical resection and to provide a reference for the development of personalized follow‐up strategies. A total of 298 patients were analyzed for their 3‐year conditional overall survival (COS3), 3‐year conditional disease‐specific survival (CDSS3), corresponding recurrence and pattern changes, and associated risk factors. The 5‐year overall survival (OS) and the 5‐year disease‐specific survival (DSS) of the entire cohort were 41.2% and 45.8%, respectively. The COS3 and CDDS3 of RGC patients who survived for 5 years were 84.0% and 89.8%, respectively. The conditional survival in patients with unfavorable prognostic characteristics showed greater growth over time than in those with favorable prognostic characteristics (eg, COS3, ≥T3: 46.4%‐83.0%, Δ36.6% vs ≤T2: 82.4%‐85.7%, Δ3.3%; P < 0.001). Most recurrences (93.5%) occurred in the first 3 years after surgery. The American Joint Committee on Cancer (AJCC) stage was the only factor that affected recurrence. Time‐dependent Cox regression showed that for both OS and DSS, after 4 years of survival, the common prognostic factors that were initially judged lost their ability to predict survival (P > 0.05). Time‐dependent logistic regression analysis showed that the AJCC stage independently affected recurrence within 2 years after surgery (P < 0.05). A postoperative follow‐up model was developed for RGC patients. In conclusion, patients with RGC usually have a high likelihood of death or recurrence within 3 years after radical surgery. We developed a postoperative follow‐up model for RGC patients of different stages, which may affect the design of future clinical trials. Patients with RGC usually have a high likelihood of death or recurrence within 3 years after radical surgery. We developed a postoperative follow‐up model for RGC patients of different stages.
Development and External Validation of Web-Based Models to Predict the Prognosis of Remnant Gastric Cancer after Surgery: A Multicenter Study
Background. Remnant gastric cancer (RGC) is a rare malignant tumor with poor prognosis. There is no universally accepted prognostic model for RGC. Methods. We analyzed data for 253 RGC patients who underwent radical gastrectomy from 6 centers. The prognosis prediction performances of the AJCC7th and AJCC8th TNM staging systems and the TRM staging system for RGC patients were evaluated. Web-based prediction models based on independent prognostic factors were developed to predict the survival of the RGC patients. External validation was performed using a cohort of 49 Chinese patients. Results. The predictive abilities of the AJCC8th and TRM staging systems were no better than those of the AJCC7th staging system (c-index: AJCC7th vs. AJCC8th vs. TRM, 0.743 vs. 0.732 vs. 0.744; P>0.05). Within each staging system, the survival of the two adjacent stages was not well discriminated (P>0.05). Multivariate analysis showed that age, tumor size, T stage, and N stage were independent prognostic factors. Based on the above variables, we developed 3 web-based prediction models, which were superior to the AJCC7th staging system in their discriminatory ability (c-index), predictive homogeneity (likelihood ratio chi-square), predictive accuracy (AIC, BIC), and model stability (time-dependent ROC curves). External validation showed predictable accuracies of 0.780, 0.822, and 0.700, respectively, in predicting overall survival, disease-specific survival, and disease-free survival. Conclusions. The AJCC TNM staging system and the TRM staging system did not enable good distinction among the RGC patients. We have developed and validated visual web-based prediction models that are superior to these staging systems.
Presence of Severe Stenosis in Most Culprit Lesions of Patients with ST-segment Elevation Myocardial Infarction
Background: Previous studies revealed that culprit vessels of ST-segment elevation myocardial infarction (STEMI) were often related to mild or moderate stenosis. However, recent studies suggested that severe stenosis was primarily found in culprit lesions. The objective of this study was to analyze the stenosis severity of culprit lesions in STEMI patients and to clarity the paradoxical results. Methods: A total of 489 consecutive STEMI patients who underwent primary percutaneous coronary intervention were retrospectively studied from January 2012 to December 2014. The patients were divided into three groups based on stenosis severity using quantitative coronary analysis: Group A, 314 cases, stenosis 〉70%: Group B, 127 cases, stenosis 50-70%: and Group C, 48 cases, stenosis 〈_50%,. The clinical, demographic, and angiographic data of all groups were analyzed. Results: Patients in Group A exhibited a significantly higher prevalence of history of angina pectoris (95.9% vs. 62.5%, P 〈 0.001 ), inultivessel disease (73.2% vs. 54.2%, P = 0.007), and lower cardiac ejection ITaction (53.3 ± 8.6 vs. 56.8 ± 8.4, P = 0.009) than those in Group C. Multivariable analysis revealed that history of angina pectoris (odds ratio [OR]: 13.89, 95% confidence interval [(7]: 6.21-31.11 ) and multivessel disease (OR: 2.32, 95%, CI: 1.25-4.31 ) were correlated with severe stenosis of the culprit lesion in Group A. Conclusions: Most culprit lesions in STEM[ patients were severe stenosis. These patients exhibited a higher prevalence of angina history and multivessel diseases.
Mechanical Properties of High-Temperature Granite under Liquid Nitrogen Cooling
The cooling characteristics of liquid nitrogen can effectively weaken the mechanical properties of dry hot rock reservoirs, improve the porosity and permeability of dry hot rock, and thus improve the development and utilization of geothermal resources. In order to explore the weakening effect of liquid nitrogen cooling characteristics on high-temperature reservoir rocks, uniaxial compression tests, Brazil splitting tests, and three-point bending tests were conducted on high-temperature granite, and synchronous acoustic emission tests were conducted to monitor the damage evolution of rocks. It is found that under the action of liquid nitrogen, the elastic modulus, peak strength, fracture toughness, and other mechanical properties of granite decrease to varying degrees. At different initial temperatures, the damage degree of liquid nitrogen to granite is different. The higher the initial temperature of granite, the greater the damage effect of liquid nitrogen on granite. The low-temperature characteristics of liquid nitrogen not only have the effect of cracking damage on granite but also have the effect of thermal stress on granite. If the temperature difference between the two is large, the heat released in the combination process will be higher. The greater the temperature difference, the greater the damage to granite. Under the action of liquid nitrogen, the acoustic emission characteristics of granite also show different evolution laws, and the ringing count of rock increases significantly, which indicates that liquid nitrogen aggravates the internal damage of granite, making the rock more fractured during fracturing. The research results can provide some scientific guidance for the development and utilization of geothermal energy.
Deformation, Permeability and Acoustic Emission Characteristics of Coal Masses under Mining-Induced Stress Paths
The geomechanical and seepage evolution characteristics of coal masses during mining are the key factors that affect the drainage of coalbed methane and the safety of coal mining. Nevertheless, the influence of mining paths on coal seam permeability is rarely investigated given the complexity of mining-induced stress experiments. To study the effect of mining-induced stress on coal mining, the mechanical properties, acoustic emission characteristics and energy evolution of coal masses were experimentally evaluated through mining-induced stress experiments. Experimental results indicated that at peak intensity, the deviatoric stress and axial strain of coal samples under the stress path of protective coal-seam mining are lower than those of coal samples under the non-pillar stress path. The unloading ratio of confining pressure is large under a stress path of non-pillar mining, and the elastic energy, the absorbed energy, and the dissipated energy of coal mass are low during destruction. The effect of high confining pressure on AE events is pronounced under the non-pillar mining path. The overall b value under high confining pressure is smaller than that under low confining pressure, and AE events generally have high energy. The fracture structure of coal mass is complex, and the fractal size of coal is large under high unloading rates of confining pressure, which induce the increase of permeability after coal destruction.
Effects of Heating and Liquid Nitrogen on Mechanical Characteristics and Rockburst Characteristics of Granite
Due to the depletion of shallow resources and the reduction of the space for human life and development, in recent years, human beings began to gradually expand to the deep underground. The increase of development depth will bring a series of safety problems, so it is particularly important to study and deal with rockburst. In this paper, based on laboratory tests, relevant literature, and research at home and abroad, the TAWD-2000 electrohydraulic servo rock mechanics testing machine and PIC-2 acoustic emission (AE) testing system are used. Uniaxial compression tests and AE monitoring tests were carried out on granite samples to analyze the property and AE characteristic parameters of granite under the action of liquid nitrogen (LN2) and to further study the fracture mode of granite. The following conclusions can be obtained: the LN2 cooling has a deterioration influence on the strength of rock, and the elastic modulus and peak stress of granite show a downward trend with the increasing number of cycles. With the cycle times of LN2 actions increasing, the AE ring count of granite and the frequency and amplitude of energy in each stage have an upward trend. When the rock reaches the failure stage, the energy at the catastrophe point increases, and the ring count also increases sharply. The RA-AF diagram of AE parameters can characterize two failure modes of rock, tensile failure and shear failure. In the process of fracture of granite samples, shear cracks dominate, leading to shear failure or compression failure of granite. Based on the method of elastic energy, the tendency index of rockburst of granite samples under different working conditions is calculated. The tendency of rockburst decreases with the decrease of elastic modulus. Under the repeated action of LN2, the tendency of rockburst of granite samples presents a downward trend, and the action of LN2 reduces the probability of rockburst to a certain extent.
Rig-I regulates NF-κB activity through binding to Nf-κb1 3′-UTR mRNA
Retinoic acid inducible gene I (RIG-I) senses viral RNAs and triggers innate antiviral responses through induction of type I IFNs and inflammatory cytokines. However, whether RIG-I interacts with host cellular RNA remains undetermined. Here we report that Rig-I interacts with multiple cellular mRNAs, especially Nf-κb1 . Rig-I is required for NF-κB activity via regulating Nf-κb1 expression at posttranscriptional levels. It interacts with the multiple binding sites within 3′-UTR of Nf-κb1 mRNA. Further analyses reveal that three distinct tandem motifs enriched in the 3′-UTR fragments can be recognized by Rig-I. The 3′-UTR binding with Rig-I plays a critical role in normal translation of Nf-κb1 by recruiting the ribosomal proteins [ribosomal protein L13 (Rpl13) and Rpl8] and rRNAs (18S and 28S). Down-regulation of Rig-I or Rpl13 significantly reduces Nf-κb1 and 3′-UTR–mediated luciferase expression levels. These findings indicate that Rig-I functions as a positive regulator for NF-κB signaling and is involved in multiple biological processes in addition to host antivirus immunity.
An elastoplastic model for gas flow characteristics around drainage borehole considering post-peak failure and elastic compaction
The excavation and drainage drilling for underground mining induces stress redistribution around the gas drainage borehole, thus forming three physical zones: residual state zone, strain softening zone and elastic zone. The formation process of these zones contains complex interactions among deformation, natural gas flow, and coal seam damage. A better understanding of these interactions could provide better guidance for the gas drainage engineering. Extensive studies have focused on the effect of effective stress or effective strain on permeability variation based on the poroelastic theory. Meanwhile, as there is few permeability models taking the post-peak failure effect into account, previous permeability variation analysis seldom commonly considered the elastoplastic characteristic of coal seam, which results in the permeability misestimation. Therefore, this study proposes a new approach to analyze this interaction process. The innovation of this approach is that it takes into account the influence of coal permeability enhancement in failure zone and the volumetric compaction in elastic zone around the drainage borehole. In this approach, analytical solutions of stress and strain are developed to include both the strain softening around a gas drainage borehole and the compaction in elastic zone. These solutions thus remove the flaws that previous studies did not consider the compaction in elastic zone. Further, a new permeability model is proposed by the introduction of damage enhancement coefficient for post-peak failure. Third, the permeability distribution of coal around a gas drainage borehole is calculated based on the analytical solutions and the new permeability model. Fourth, the gas flow equation is numerically solved to obtain gas pressure profiles. The gas content computed by this approach is verified by field data. Finally, parametric study is carried out to investigate the effect of the damage enhancement coefficient, initial geo-stress, drilling volume, and uniaxial strength on the gas pressure and the permeability around the gas drainage borehole. Based on these numerical analyses, it is found that the evolution of permeability is closely related to the physical properties of coal and the geological condition of coal seam. Higher initial geo-stress and lower failure strength have larger unloading zone and higher permeability enhancement. This compaction helps the coal seam form a flow-shielding zone near the interface between plastic zone and elastic zone. The gas flow in the coal around the drainage borehole can be divided into four different zones.
Effect of Liquid Nitrogen Cooling and Heating on Mechanical Properties and Acoustic Emission Characteristics of Coal
The instability of rock fractures has been extensively studied in domestic and international research. This paper investigates two coal types from the Jiaozuo area, which were subjected to liquid nitrogen cyclic treatment using Brazil’s indirect tensile testing (BITT). The study analyzes the characteristics of acoustic emission (AE) and crack formation during the coal cracking process and evaluates the impact of freeze-thaw treatment with liquid nitrogen cycles on the mechanical properties of coals. The results demonstrate that liquid nitrogen has a significant impact on the formation and development of coal fractures under the Brazil splitting test conditions. As the number of cyclic treatments increases, the maximum load-bearing capacity of coal decreases, indicating a gradual reduction in the effective stress on coal samples. Furthermore, the acoustic emission activity intensity of coal mass during phased loading increases as the number of freeze-thaw cycles of liquid nitrogen increases. Finally, during phased loading of coal specimens, the primary factor is the germination, extension, and failure of tensile cracks, while the secondary factor is the development, extension, and failure of shear cracks. Overall, this study provides valuable insights into the behavior of coals under freeze-thaw cycles of liquid nitrogen treatment and highlights the importance of understanding the characteristics of coal fracture instability.
Assessment of the Nonlinear Flow Characteristic of Water Inrush Based on the Brinkman and Forchheimer Seepage Model
Underground fault water inrush is a hydrogeological disaster that frequently occurs in underground mining and tunnel construction projects. Groundwater may pour from an aquifer when disasters occur, and aquifers are typically associated with fractured rock formations. Water inrush accidents are likely to occur when fractured rock masses are encountered during excavation. In this study, Comsol Multiphysics, cross-platform multiphysics field coupling software, was used to simulate the evolution characteristics of water flow in different flow fields of faults and aquifers when water inrush from underground faults occurs. First, the Darcy and Brinkman flow field nonlinear seepage models were used to model the seepage law of water flow in aquifers and faults. Second, the Forchheimer flow field was used to modify the seepage of fluid in fault-broken rocks in the Brinkman flow field. In general, this phenomenon does not meet the applicable conditions of Darcy’s formula. Therefore, the Darcy and Forchheimer flow models were coupled in this study. Simulation results show that flow behavior in an aquifer varies depending on fault permeability. An aquifer near a fault is likely to be affected by non-Darcy flow. That is, the non-Darcy effect zone will either increase or decrease as fault permeability increases or decreases. The fault rupture zone that connects the aquifer and upper roadway of the fault leads to fault water inrush due to the considerably improved permeability of the fractured rock mass.