Experimental study of mechanical property for prestressed rubber bearing

To overcome the shortages of existing Rubber Bearings (RBs), an innovative type of isolator, named as Prestressed Rubber Bearing (PRB), is presented in this paper. Base on conventional laminated Rubber Bearing (RB), PRB is developed by increasing the thickness of rubber layers, setting vertical ducts and installing prestress tendons. Through the vertical and horizontal monotonic loading test, the vertical and horizontal stiffness of PRBs are investigated. The empirical formulas for stiffness are proposed. Moreover, the hysteresis behavior and the energy dissipation capacity of PRBs are studied by reversed cyclic loading test. The results show that PRBs not only have the horizontal isolating capacity as conventional RBs, but also have the capacity of horizontal displacement-limitation and improved capacity of energy dissipation

Stability Analysis of ITER Side Correction Coils

AbstractThe stability of the Side Correction Coils (SCC) cable-in-conduit conductors (CICC) for the International Thermonuclear Experimental Reactor (ITER) has been analyzed by the formulas and the code Gandalf. This paper describes the 1-dimensional mathematical code Gandalf, uses the code to simulate the quench and the recovery status of ITER SCC CICC, discusses the dependence of the stability margin on various operating parameters including operating current, operating temperature and mass flow rate, and analyzes the differences between the simulated values and the calculated values. The ITER SCC's quenching is also simulated to investigate its temperature distribution and temperature margin. Dependence of temperature margin on magnetic fields and operating temperature has been researched. The studies of ITER SCC provide a basis for the stable operation and optimization design of SCC CICC

Pituitary stalk changes on magnetic resonance imaging following pituitary adenoma resection using a transsphenoidal approach

ObjectiveWe aimed to investigate the magnetic resonance imaging (MRI) findings and clinical significance of position and changes in morphology of the pituitary stalk following pituitary adenoma (PA) resection using a transsphenoidal approach.MethodsWe collected clinical and MRI data of 108 patients with PA after transsphenoidal surgery. Diameter, length, and coronal deviation of the pituitary stalk were measured pre-, post-, and mid-term post-operatively, to observe pituitary stalk morphology.ResultsOf 108 patients, 53 pituitary stalks were recognisable pre-operatively. The angle between the pituitary stalk and the median line was 7.22°-50.20° (average, 25.85°) in 22 patients with left-sided pituitary stalks and 5.32°-64.05° (average, 21.63°) in 20 patients with right-sided pituitary stalks. Of 42 patients with preoperative pituitary stalk deviation, 41 had an early postoperative recovery and 1 had increased deviation. In the mid-term postoperative period, 21 of 42 patients had pituitary stalks located centrally. In 53 patients, the pituitary stalk length was 1.41–11.74 mm (mean, 6.12 mm) pre-operatively, 3.61–11.63 mm (mean, 6.93 mm) in the early postoperative period, and 5.37–17.57 mm (mean, 8.83 mm) in the mid-term postoperative period. In the early postoperative period, 58 (53.70%) patients had posterior pituitary bright spots (PPBS) and 28 (25.92%) had diabetes insipidus (DI).ConclusionPre-operatively, the pituitary stalk was compressed and thinned. Post-operatively, it could be stretched to a “normal state”, and its position showed a gradual centring trend. Post-operatively, the length of the pituitary stalk gradually increased. The PPBS in the early postoperative period negatively correlated with postoperative DI

GLUT3 expression in cystic change induced by hypoxia in pituitary adenomas

Tumor cells require large amounts of energy to sustain growth. Through the mediated transport of glucose transporters, the uptake and utilization of glucose by tumor cells are significantly enhanced in the hypoxic microenvironment. Pituitary adenomas are benign tumors with high-energy metabolisms. We aimed to investigate the role of expression of glucose transporter 3 (GLUT3) and glucose transporter 1 (GLUT1) in pituitary adenomas, including effects on size, cystic change and hormone type. Pituitary adenomas from 203 patients were collected from January 2013 to April 2017, and immunohistochemical analysis was used to detect the expression of GLUT3 and GLUT1 in tumor specimens. GLUT3-positive expression in the cystic change group was higher than that in the non-cystic change group (P = 0.018). Proportions of GLUT3-positive staining of microadenomas, macroadenomas, and giant adenomas were 22.7 (5/22), 50.4 (66/131) and 54.0% (27/50), respectively (P = 0.022). In cases of prolactin adenoma, GLUT3-positive staining was predominant in cell membranes (P = 0.000006), while in cases of follicle-stimulating hormone or luteotropic hormone adenoma, we found mainly paranuclear dot-like GLUT3 staining (P = 0.025). In other hormonal adenomas, GLUT3 was only partially expressed, and the intensity of cell membrane or paranuclear punctate staining was weak. In contrast to GLUT3, GLUT1 expression was not associated with pituitary adenomas. Thus, our results indicate that the expression of GLUT3 in pituitary adenomas is closely related to cystic change and hormonal type. This study is the first to report a unique paranuclear dot-like GLUT3 staining pattern in pituitary adenomas

Using object-oriented coupled deep learning approach for typical object inspection of transmission channel

Traditional methods to inspect transmission line passage are mostly through UAV/helicopters and manual inspection, which are limited in no man's area and large-scale inspection. Satellite remote sensing technology breaks through such limitations and makes it more possible to inspect transmission line passage on a large scale in the power industry. Therefore, adopting the WorldView-3 satellite image with high resolution as the data source, we propose a typical ground object inspection method based on the object-oriented method coupled with the deep learning method. Firstly, in view of the traditional object-oriented multicategory extraction phenomenon, we use multiscale segmentation technology to construct the typical feature classification rule set and optimize the segmentation threshold. Through prior knowledge and experiments, we explore the best inspection sequence of multicategory typical features. Secondly, we use a fully convolutional neural network to perform end-to-end inspections of typical features. Finally, we propose the combination of the two methods to make it act on an image by comparing the inspection results of each typical ground object category and analyzing the advantages and disadvantages of the above two methods. Based on the principle of optimal inspection sequence, the user flexibly selects target extraction methods and finally the typical ground object inspection results are output end-to-end. The research shows that the coupled method has the highest inspection accuracy. The overall inspection accuracy reaches 93.01%, which is 10.32% and 8.07% higher than that of the object-oriented method and the deep learning method. The Macro-F1 score is 0.8363, which is 0.124 and 0.1532 higher than that of the object-oriented method and the deep learning method. We also choose Lingwu City for a verification experiment. The result shows that the overall inspection accuracy for the new experimental area is 91.25%, and the Macro-F1 score is 0.8948, indicating that the algorithm has versatility

Efficacy of sellar opening in the pituitary adenoma resection of transsphenoidal surgery influences the degree of tumor resection

Abstract Background Endonasal transsphenoidal microsurgery is often adopted in the resection of pituitary adenoma, and has showed satisfactory treatment and minor injuries. It is important to accurately localize sellar floor and properly incise the bone and dura matter. Methods Fifty-one patients with pituitary adenoma undergoing endonasal transsphenoidal microsurgery were included in the present study. To identify the scope of sellar floor opening, CT scan of the paranasal sinus and MRI scan of the pituitary gland were performed for each subject. Intraoperatively, internal carotid artery injury, leakage of cerebrospinal fluid, and tumor texture were recorded, and postoperative complications and residual tumors were identified. Result The relative size of sellar floor opening significantly differed among the pituitary micro-, macro- and giant adenoma groups, and between the total and partial tumor resection groups. The ratio of sellar floor opening area to maximal tumor area was significantly different between the total and partial resection groups. Logistic regression analysis revealed that the ratio of sellar floor opening area to the largest tumor area, tumor texture, tumor invasion and age were independent prognostic factors. The vertical distance between the top point of sellar floor opening and planum sphenoidale significantly differed between the patients with and without leakage of cerebrospinal fluid. Conclusion These results together indicated that relatively insufficient sellar floor opening is a cause of leading to residual tumor, and the higher position of the opening and closer to the planum sphenoidale are likely to induce the occurrence of leakage of cerebrospinal fluid

Monofluoromethylation of Cyclic Sulfamidates and Sulfates with a-Fluorocarbanions of Fluorobis(phenylsulfonyl)methane and Ethyl 2-Fluoroacetoacetate

A regioselective fluoromethylation by ring-opening of cyclic sulfamidates and sulfates with a-fluorocarbanions and subsequent reductive desulfonylation is developed. Fluorobis(phenylsulfonyl)methane (FBSM) was explored as fluoromethide equivalent and the reaction was extended to the afluorocarbanion of ethyl 2-fluoroacetoacetate. This approach allows access to g-and d-fluoroamines as well as g-and d-fluoroalcohols in high yields

Pre- and Postoperative Magnetic Resonance Imaging Comparative Studies of Pituitary Tissues Following Transsphenoidal Resection of Pituitary Macroadenomas

Background: Magnetic resonance imaging (MRI) has become the most important radiological procedure for diagnosing and following pituitary tumors. But previous MRI studies on pituitary adenomas are mainly focused on the posterior pituitary. Few research has been done on residual normal pituitary tissue before and after transsphenoidal surgery. This retrospective cohort study investigates the pre- and postoperative magnetic resonance imaging characteristics of normal pituitary tissues regarding transsphenoidal resection of pituitary macroadenomas. Methods: Pre- and postoperative magnetic resonance imaging scanning of 112 consecutive pituitary macroadenoma patients who underwent tumor resection via transsphenoidal approach was performed, and their medical records were studied. Results: On preoperative MRI, 66 cases of pituitary stalks were identifiable, 9 of them were roughly in the middle, and 57 cases showed left or right deviation, with the angle between pituitary stalks and the sagittal plane was 5.32°–64.05° (average 21.65°). Among the 57 patients with preoperative pituitary stalk deviation, 55 of the pituitary stalk deviations improved in 1 week after surgery, and 30 cases were almost in the middle in 4–6 months after operation, with the other cases get better in varying degrees. The diameter of pituitary stalk was 1.08–3.89 mm (mean 2.36 mm) in pre-operation, and 1.29–3.43 mm (mean 2.30 mm) in 4–6 months after operation. The length of pituitary stalk was 1.41–11.74 mm (mean 6.12 mm) preoperatively, 3.61–11.63 mm (mean 6.93 mm) early postoperatively, and 5.37–17.57 mm (mean 8.83 mm) in 4–6 months after operation. Pituitary stalk was thickened or compressed on preoperative MR images, and gradually recovered to normal during postoperative period. It tended to be in the middle position and its length increased gradually until 4–6 months after operation. On preoperative MRI, 69 out of 112 patients showed residual pituitary tissues (RPT)(+) on enhanced MRI. RPT were likely located above the adenomas in somatotroph adenoma patients. Morphological restitution of postoperative normal pituitary tissues was better in lateral displacement than in superior or superolateral patterns on preoperative magnetic resonance imaging. Postoperative normal pituitary tissues usually subsided directly in superior displacement pattern on preoperative MRI, while were likely to be confined in the lateral side in lateral and superolateral displacement patients. Postoperative morphologic remodeling grade of RPT was positively correlated with the maximum diameter of pituitary adenoma (p = 0.000), but not with age. Conclusions:The larger the tumor diameter, the worse the pituitary morphological recovery after tumor resection. Relative locations of normal pituitary and adenoma tissues may be related to adenoma type and may affect postoperative reconstruction of residual normal pituitary tissues. These findings enable surgeons to distinguish pituitary tissue from residual or recurring tumor tissue on postoperative magnetic resonance imaging

Study on Critical Concentration of Dynamic Gelation of New Chromium Crosslinker

A chrome gel system with 13 million molecular weight and 19 million molecular weight polymer and DQ-8 cross-linking agent is dynamically gelled under different conditions of 50-mesh and 100-mesh screens under different shear rates. Concentration limit. The experiment shows that the critical concentration of 13 million molecular weight gelation is 500-700mg/L, and the critical concentration of new cross-linking agent in the system is 80mg/L-90mg/L. The system of new cross-linker is cut by steel mesh. The post-gelation time is prolonged. Between 6h-10h, after 12 days of testing, the viscosity of the chrome gel system after gelation can still remain above 1000mPa·s, and the viscosity of the ungelatinized solution drops below 10mPa·s