Up-Regulated Maternal Embryonic Leucine Zipper Kinase Predicts Poor Prognosis of Hepatocellular Carcinoma Patients in a Chinese Han Population.

BACKGROUND Maternal embryonic leucine zipper kinase (MELK) has been implicated in various types of tumors, but its expression profile and clinicopathologic significance in hepatocellular carcinoma (HCC) in Chinese Han people remains unknown. Therefore, this study attempted to investigate the expression pattern of MELK in HCC tissues obtained from a Chinese Han population. MATERIAL AND METHODS The expression of MELK, from RNA to protein levels, in HCC or disease-free human liver tissues was evaluated using quantitative real-time polymerase chain reaction assays and immunohistochemistry staining, and its prognostic significance was determined based on its impact on HCC patients' survival. RESULTS We found that HCC tissues expressed a higher level of MELK RNA than non-tumor tissues in tumor-related public databases (P<0.001). Hence, we assessed MELK mRNA expression within 32 HCC samples and their adjacent non-tumorous liver tissues in our center. Subsequently, MELK protein expression was evaluated within 101 HCC specimens and 40 disease-free liver tissues. Notably, it revealed that high MELK protein expression was significantly related with tumor number, tumor size, higher pathological tumor-nodule-metastasis stage, vascular invasion, and recurrence (P<0.05, all). Furthermore, elevated MELK protein expression was correlated with decreased overall survival and disease-free survival (P=0.004 and P=0.002, respectively). Univariate and multivariate analysis results show that MELK protein may serve as an independent prognostic indicator for determining prognosis of HCC patients. CONCLUSIONS We found that, in a Chinese Han population, MELK was highly expressed within HCC tissues from RNA to protein levels, and may be a potential independent prognostic biomarker for HCC patients.

The Variation Patterns of the Martensitic Hierarchical Microstructure and Mechanical Properties of 35Si2MnCr2Ni3MoV Steel at Different Austenitizing Temperatures.

This study investigates the influence of varying austenitizing temperatures on the microstructure and mechanical properties of 35Si2MnCr2Ni3MoV steel, utilizing Charpy impact testing and microscopic analysis techniques such as scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD). The findings reveal that optimal combination of strength and toughness is achieved at an austenitizing temperature of 980 °C, resulting in an impact toughness of 67.2 J and a tensile strength of 2032 MPa. The prior austenite grain size initially decreases slightly with increasing temperature, then enlarges significantly beyond 1100 °C. The martensite blocks' and packets' structures exhibit a similar trend. The proportion of high-angle grain boundaries, determined by the density of the packets, peaks at 980 °C, providing maximal resistance to crack propagation. The amount of retained austenite increases noticeably after 980 °C; beyond 1200 °C, the coarsening of packets and a decrease in density reduce the likelihood of trapping retained austenite. Across different austenitizing temperatures, the steel demonstrates superior crack initiation resistance compared to crack propagation resistance, with the fracture mode transitioning from ductile dimple fracture to quasi-cleavage fracture as the austenitizing temperature increases.

Morphology and Distribution of Primary Carbides in Forged Cr-Ni-Mo-V/Nb Steel.

This study aims to investigate in situ the three-dimensional (3D) morphology and distribution of primary carbides (PCs) in electro-slag remelting (ESR) forged 30Cr3Ni3Mo2V steel. A facile non-aqueous electrolytic etching method was applied to prepare 3D PCs on the matrix. The morphology, composition, and element concentrations of PCs were characterized using a combination of optical microscopy (OM), scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), and electron back-scattered diffusion (EBSD). The precipitation, type, and composition of PCs in the same steel were also simulated using Thermo-Calc software Version 2015a. The results indicate that PC is rich in Nb, which is a potential heterogeneous nucleating agent. Both the size and number of PCs increase from the edge to the center of the ingot. The large-sized PCs present three dominant types of morphology, which vary in different regions, i.e., a bulky type dominates in the edge region, a lamellar type dominates in the middle region, and a stripy type dominates in the core region. The results of EBSD analysis show that the orientation of PCs with different morphologies is different and that more nanosized V-rich type carbides are precipitated on the matrix. The thermodynamic calculations show that MC precipitates from the liquid phase when the solid phase fraction is greater than 0.985 and that the MC-type carbides are rich in Nb, which agrees well with the experimental results.

Undifferentiated high-grade pleomorphic sarcoma of the common bile duct: A case report and review of literature.

BACKGROUND: Undifferentiated pleomorphic sarcoma (UPS) is a rare malignant mesenchymal tumor with a poor prognosis. It mainly occurs in the extremities, trunk, head and neck, and retroperitoneum regions. Owing to the lack of specific clinical manifestations and imaging features, UPS diagnosis mainly depends on pathological and immunohistochemical examinations for exclusive diagnosis. Here we report an extremely rare case of high-grade UPS in the common bile duct (CBD). There are limited available data on such cases. CASE SUMMARY: A 70-year-old woman was admitted to our department with yellow eyes and urine accompanied by upper abdominal distending pain for 2 wk. Her laboratory data suggested significantly elevated hepatorenal function levels. The imaging data revealed calculous cholecystitis, intrahepatic and extrahepatic bile duct dilation with extrahepatic bile duct calculi, and a space-occupying lesion at the distal CBD. After endoscopic biliary stenting and symptomatic support therapy, CBD exploration and biopsy were performed. The frozen section indicated malignant spindle cell tumor of the CBD mass, and further radical pancreaticoduodenectomy was performed. Finally, the neoplasm was diagnosed as a high-grade UPS combined with the light-microscopic morphology and immunohistochemical results. CONCLUSION: This extremely rare case highlighted the need for increasing physicians' vigilance, reducing the odds of misdiagnosis, and providing appropriate treatment strategies.

Regulation Law of Tempering Cooling Rate on Toughness of Medium-Carbon Medium-Alloy Steel.

Temper embrittlement is a major challenge encountered during the heat treatment of high-performance steels for large forgings. This study investigates the microstructural evolution and mechanical properties of Cr-Ni-Mo-V thick-walled steel, designed for large forgings with a tensile strength of 1500 MPa, under different tempering cooling rates. Optical microscopy (OM), scanning electron microscopy (SEM), and electron backscatter diffraction (EBSD) were employed to analyze the microstructural features. The results demonstrate that the embrittlement occurring during air cooling after tempering is attributed to the concentration of impurities near Fe3C at the grain boundaries. The low-temperature impact toughness at -40 °C after water quenching reaches 29 J due to the accelerated cooling rate during tempering, which slows down the diffusion of impurity elements towards the grain boundaries, resulting in a reduced concentration and dislocation density and an increased stability of the grain boundaries, thereby enhancing toughness. The bainite content decreases and the interface between martensite and bainite undergoes changes after water quenching during tempering. These alterations influence the crack propagation direction within the two-phase microstructure, further modifying the toughness. These findings contribute to the understanding of temper embrittlement and provide valuable guidance for optimizing heat treatment processes to enhance the performance of high-performance steels in large forgings.

Dissolution Behavior of Eutectic Carbides in Medium-Alloy Steels for Heavy Forgings.

In this study, we investigate the dissolution behavior of eutectic carbides in heavy forgings. High-temperature diffusion treatment was conducted on 35Cr3Ni3MoVW2 (MoVW2) and 35Cr2Ni3MoV (MoV) steels at 1230 °C for a duration ranging from 0 to 100 h. The dissolution of eutectic carbides and its effects on the microstructure and hardness of the steels were characterized and analyzed via SEM+EBSD, ImageJ, and Thermo-Calc. The results show that the coarse eutectic carbides in both steels gradually dissolved. The distribution and morphology tend to be uniform and spherical, respectively. For holding 50 h, the hardness of both steels significantly exhibited an increasing trend, and it was attributed to the combined effects of solid solution strengthening. Thermodynamic calculations indicated that the higher W content in MoVW2 steel promoted the precipitation of M6C eutectic carbides. Moreover, both MoVW2 and MoV steels exhibited the precipitation of M7C3 eutectic carbides in the final stage of solidification, facilitated by the enrichment of C and Cr in the liquid steels.

CircZFR promotes pancreatic cancer progression through a novel circRNA-miRNA-mRNA pathway and stabilizing epithelial-mesenchymal transition protein.

Pancreatic cancer (PC) ranks third in incidence and seventh in mortality among cancers worldwide. CircZFR has been implicated in various human cancers. Yet, how they affect PC progression is understudied. Herein, we demonstrated that circZFR was upregulated in PC tissues and cells, a feature that was correlated with the poor performance of patients with PC. Functional analyses elucidated that circZFR facilitated cell proliferation and enhanced tumorigenicity of PC. Moreover, we found that circZFR facilitated cell metastasis by differentially regulating the levels of proteins related to epithelial-mesenchymal transition (EMT). Mechanistic investigations revealed that circZFR sponged miR-375, thereby upregulating the downstream target gene, GREMLIN2 (GREM2). Additionally, circZFR knockdown resulted in attenuation of the JNK pathway, an effect that was reversed by GREM2 overexpression. Collectively, our findings implicate circZFR as a positive regulator of PC progression through the miR-375/GREM2/JNK axis.

Effect of Material Anisotropy on the Mechanical Response of Automotive Steel under High Strain Rates.

A constitutive model for automobile steel with high elongation needs to be established to predict the dynamic deformation behavior under hydroforming applications. In order to clarify the confusing discrepancy in the essential parameters of the classical Cowper-Symonds (C-S) model, a series of automobile structural steels have been employed to investigate the strain rate response by conducting tensile dynamic deformation. Metallographic microscopy and orientation distribution functions were used to characterize the microstructure and texture components of the steels. The microstructure observation discloses that the matrix of all steels is mainly of ferrite and the texture constituent provides a framework for steel to withstand external deformation. The C-S model can be applied to simulate the dynamic deformation with satisfied expectations. It is concluded that the essential parameters D and p in the model show a specific relationship with the steel grade, and the parameter D is proportional to the steel grade and related to material anisotropy, while the parameter p is inversely proportional to the steel grade and has close links with the grain boundary characteristics.

Anastomosing hemangioma arising from the left renal vein: A case report.

BACKGROUND: Anastomosing hemangioma (AH) is a rare subtype of benign hemangioma that is most commonly found in the genitourinary tract. Due to the lack of specific clinical and radiologic manifestations, it is easily misdiagnosed preoperatively. Here, we report a case of AH arising from the left renal vein that was discovered incidentally and confirmed pathologically, and then describe its imaging characteristics from a radiologic point of view and review its clinicopathologic features and treatment. CASE SUMMARY: A 74-year-old woman was admitted to our department for a left retroperitoneal neoplasm measuring 2.6 cm × 2.0 cm. Her laboratory data showed no significant abnormalities. A non-contrast-enhanced computed tomography (CT) scan showed a heterogeneous density in the neoplasm. Non-contrast-enhanced magnetic resonance imaging (MRI) revealed a heterogeneous hypointensity on T1-weighed images and a heterogeneous hyperintensity on T2-weighed images. On contrast-enhanced CT and MRI scans, the neoplasm presented marked septal enhancement in the arterial phase and persistent enhancement in the portal phase, and its boundary with the left renal vein was ill-defined. Based on these clinical and radiological manifestations, the neoplasm was initially considered to be a neurogenic neoplasm in the left retroperitoneum. Finally, the neoplasm was completely resected and pathologically diagnosed as AH. CONCLUSION: AH is an uncommon benign hemangioma. Preoperative misdiagnoses are common not only because of a lack of specific clinical and radiologic manifestations but also because clinicians lack vigilance and diagnostic experience in identifying AH. AH is not exclusive to the urogenital parenchyma. We report the first case of this neoplasm in the left renal vein. Recognition of this entity in the left renal vein can be helpful in its diagnosis and distinction from other neoplasms.

Design of infrared radiation diagnostic calorimeter for the prototype radio frequency driven negative ion source for neutral beam injection.

In order to study the generation and extraction of negative ions for neutral beam injection application, a prototype radio frequency driven negative ion source and the corresponding test bench are under construction at the Institute of Plasma Physics, Chinese Academy of Sciences. A new design of infrared radiation diagnostic calorimeter for testing beam characteristics is put forward. Compared with the conventional calorimeter, the calorimeter adopts the block structure (8 × 28 tungsten hexahedron blocks) and modularization design (4 modules), so it has higher precision and good scalability. The thermal performance of the calorimeter is assessed using a finite element method. Simulation results show that the design can be achieved to operate in the stable-state mode at the maximum thermal flux 6.45 MW/m2 and meet the full requirement of beam diagnosis.

Preliminary result of cavity ring-down spectroscopy system for radio frequency negative ion source test facility.

Negative ion source is a core part of the neutral beam injection system for magnetic confinement fusion devices. The density of produced hydrogen negative ions is a critical parameter of the negative ion source. Cavity ring-down spectroscopy (CRDS) is an ultrasensitive absorption diagnostic technique for density measurement. Based on the photodetachment process, CRDS can measure the integrated line-of-sight hydrogen negative ion density in a high power ion source. The CRDS diagnostic system has been applied to Hefei utility negative ion test equipment with the radio frequency (RF) source, which is now one of the references for the China Fusion Engineering Test Reactor neutral beam injection system. Typical ring-down signals are obtained to calculate the density of hydrogen negative ions. The time evolution of hydrogen negative ion density is successfully measured. Preliminary experiments show the accurate relationship between RF power and measured hydrogen negative ion density.

Radiological aspects of giant hepatocellular adenoma of the left liver: A case report.

BACKGROUND: Hepatocellular adenoma (HCA) is very rare and has a high misdiagnosis rate through clinical and imaging examinations. We report a case of giant HCA of the left liver in a young woman that was diagnosed by medical imaging and pathology. CASE SUMMARY: A 21-year-old woman was admitted to our department for a giant hepatic tumor measuring 22 cm × 20 cm × 10 cm that completely replaced the left hepatic lobe. Her laboratory data only suggested mildly elevated liver function parameters and C-reactive protein levels. A computed tomography (CT) scan showed mixed density in the tumor. Magnetic resonance imaging (MRI) of the tumor revealed a heterogeneous hypointensity on T1-weighed MR images and heterogeneous hyperintensity on T2-weighed MR images. On dynamic contrast CT and MRI scans, the tumor presented marked enhancement and the subcapsular feeding arteries were clearly visible in the arterial phase, with persistent enhancement in the portal and delayed phases. Moreover, the tumor capsule was especially prominent on T1-weighted MR images and showed marked enhancement in the delayed phase. Based on these imaging manifestations, the tumor was initially considered to be an HCA. Subsequently, the tumor was completely resected and pathologically diagnosed as an HCA. CONCLUSION: HCA is an extremely rare hepatic tumor. Preoperative misdiagnoses were common not only due to the absence of special clinical manifestations and laboratory examination findings, but also due to the clinicians' lack of practical diagnostic experience and vigilance in identifying HCA on medical images. Our case highlights the importance of the combination of contrast-enhanced CT and MRI in the preoperative diagnosis of HCA.

Physics and engineering design of 400 keV H- accelerator for negative ion based neutral beam injection system in China.

A research project of the China Fusion Engineering Test Reactor (CFETR) Negative ion-based Neutral Beam Injection (NNBI) prototype has been started in China. The objectives of the CFETR NNBI prototype are to produce a negative hydrogen ion beam of >20 A up to 400 keV for 3600 s and to attain a neutralization efficiency of >50%. In order to identify and optimize the design of the negative ion accelerator, a self-consistent model has been developed to consider all key physics and engineering issues (electric and magnetic fields, background gas flow, beam optics, beam-gas interaction, secondary particle trajectories, power deposition on grids, heat removal design, and mounting pattern). This paper presents the primary results by applying the self-consistent model to the current design of the 400 keV H- accelerator of the CFETR NNBI prototype.

Structure design and analysis of RF ion source for negative ion source test facility.

A negative ion source acts as a critical part in a neutral beam injector (NBI). A high current ion source is required for the high-power NBI. In this paper, a prototype radio frequency (RF) ion source and its test facility are developed in the Institute of Plasma Physics, Chinese Academy of Sciences, to demonstrate the key technology of the high power negative ion source. The structure design of the RF negative ion source is presented, involving the designs of the ion source plasma generator and accelerator. The detailed structure design and analysis of the key parts of the ion source are also presented, such as the Faraday shield (FS) and accelerator grids. The fluid-thermal-structural coupling characteristics of the FS and grid are explored with different mechanisms of fluid pressure, RF power, and the structure type on the thermal stress. Then, the processing and manufacturing scheme of the FS and grids are also given. Finally, the results were presented with a manufactured three cooling channel FS. The experimental results prove that the developed structure design of the RF ion source is effective and reliable, and the correctness of finite element analysis is also verified by experimental data comparison.

Optimization design of magnetic filter for the prototype RF negative ion source at ASIPP.

For a prestudy of the key science and technology of the RF negative ion source for fusion application, a negative RF ion source test facility was developed at the Institute of Plasma Physics, Chinese Academy of Science (ASIPP). The magnetic filter field in front of the extraction system plays an important role in reducing the loss of negative hydrogen ions and inhibiting coextraction of electrons. The existing filter field of the prototype ion source is generated by permanent magnets arranged on both sides of the expansion chamber; the gradient and the uniformity of the field are poor, resulting in a large plasma distribution unevenness in the experiment. In order to reduce the B→×∇B drift and the beam deflection, the plasma nonuniformity, and the beam alignment, its gradient should be as low as possible, especially near the Plasma Grid (PG), while its strength should be as low as possible inside both the driver and the extraction region. Hence, the magnetic filter field generated by the permanent magnet and the PG current with return wires is proposed. A finite element analysis method is used to calculate the distribution of the magnetic field throughout the ion source, especially the filter profile along the centerline perpendicular to the PG and the section parallel to the PG. Several cases were compared and the final design provides a more uniform magnetic field in the region within 70 mm above the plasma grid, while the field strength is around 5 mT and the integral BdL quantity is greater than 1.2 mTm.

Preliminary design of diagnostic system for negative neutral beam injector at ASIPP.

According to the latest physics design of the China Fusion Engineering Test Reactor (CFETR), two neutral beam injectors (NBIs), which deliver a total of 40 MW in not less than 3600 s with 1 MeV D0, are demanded to support current drive and plasma rotation. To minimize the risks and time to provide the CFETR with reliable NBIs, a negative NBI test facility will be developed at the Institute of Plasma Physics, Chinese Academy of Science. Its mission is to understand the characteristics of the RF driven ion source and negative ion generation and extraction and to improve RF efficiency and beam quality. In order to achieve this goal, a set of diagnostic tools will be used in this test facility. For source diagnostics, optical emission spectroscopy, cavity ring-down spectroscopy, laser absorption spectroscopy, and electrostatic probes are planned to be used. Beam emission spectroscopy, W-wire calorimeters, 1D carbon fiber composite diagnostic calorimeters, beam dump with thermocouples, and water-flow calorimetry are used to assess the beam properties. The design of the diagnostic system is presented.

Research and development progress of radio frequency ion source for neutral beam injector at ASIPP.

Neutral beam injection (NBI) is one of the most effective tools of four auxiliary plasma heating methods for fusion plasma heating and current drive. Now, a next generation fusion device, China Fusion Engineering Test Reactor, is under design, and a large negative NBI is foreseen. In order to demonstrate the key technology and performance of a negative ion source, a negative radio frequency (RF) ion source test facility has been developed since 2017 in the Institute of Plasma Physics, Chinese Academy of Science. A prototype RF ion source with double drivers (having the same structure with an inner diameter of 200 mm) was developed and tested on the test facility to preresearch the key technology of the RF plasma generator. The driver is equipped with a water-cooled Faraday shield to protect the alumina cylinder from the plasma, and the plasma expands into the rectangular expansion chamber. The RF power of 100 kW with a frequency of 1 MHz is transferred to the RF driver by a matching unit. The characteristics of plasma discharge were studied with classical diagnostic tools, such as the Langmuir probe and water flow calorimeter. Based on the plasma performance tests, a high power of 82 kW plasma discharge for a long pulse of 1000 s was achieved. In this paper, the details of the ion source design, characteristics of plasma, and future research plan will be presented.

Development and preliminary results of radio frequency ion source.

A radio frequency (RF) ion source was designed and developed for neutral beam injector. A RF driver test bed was used with a RF generator with maximum power of 25 kW with 1 MHz frequency and a matching box. In order to study the characteristic of RF plasma generation, the capacitance in the matching box was adjusted with different cases. The results show that lower capacitance will better the stability of the plasma with higher RF power. In the future, new RF coils and matching box will be developed for plasma generators with higher RF power of 50 kW.

Development of a core snubber for the neutral beam injector on EAST.

A 4-MW ion source was developed for the neutral beam injector (NBI) on Experimental Advanced Superconducting Tokamak (EAST). Breakdown nevertheless can happen during ion source conditioning and routine operations and is deleterious to the high-power ion source. To protect this ion source, a core snubber was designed to absorb the breakdown energy of the EAST-NBI ion source. A prototype core snubber was developed and tested using the ion-source test bed. The results show that with a core snubber, short-circuit currents at different high-power voltages were about one-tenth of the current without the snubber. The residual energy of the distributed capacitors had been absorbed successfully and the core snubber does protect the source from damage during breakdown. The results verified the successful development of a core snubber for the EAST-NBI.

Performance of positive ion based high power ion source of EAST neutral beam injector.

The positive ion based source with a hot cathode based arc chamber and a tetrode accelerator was employed for a neutral beam injector on the experimental advanced superconducting tokamak (EAST). Four ion sources were developed and each ion source has produced 4 MW @ 80 keV hydrogen beam on the test bed. 100 s long pulse operation with modulated beam has also been tested on the test bed. The accelerator was upgraded from circular shaped to diamond shaped in the latest two ion sources. In the latest campaign of EAST experiment, four ion sources injected more than 4 MW deuterium beam with beam energy of 60 keV into EAST.