• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.12
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• pp.46-55
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• 2014

PCB design technology for high-speed transmission line has been developed continuously. Adapting to the high capacity of the communication system, switch fabric interface used for backplane is being standardized to accommodate more than 10Gbps serial interface. In this paper, various computer simulations are performed to compare the performance of each transmission line per length according to PCB material, and also to analyze the effect from via stub length and crosstalk, for the purpose of applying 11.5Gbps serial interface as a switch fabric interface in tera-bit switching system. As a result of the simulation, important design issues, such as PCB material of each board supporting 8dB improvement in transmission loss using low loss PCB, maximum available stub length on transmission line via, whether or not to apply the backdrill process to the via, and the clearance of the differential pair between transmission lines, are determined. The most efficient system architecture which could be applied 11.5Gbps serial interface in all switch fabric interfaces is defined from the simulation results.

• Journal of Korean Academy of Nursing
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• v.25 no.3
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• pp.457-471
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• 1995

This research was done to promote improvement of practical application of nursing diagnoses and to improve the quality of nursing. The subjects of this research were 156 second year students of C junior nursing college who were giving adult patient care. The nursing diagnoses of 312 reports were analyzed using NANDA. In these case reports only nursing diagnoses were considered, of which there were a total of 982. In the data analysis the 9H of the nursing students' nursing diagnoses matched with 105 NANDA nursing diagnoses, Of these, the most frequent diagnoses were pain(165, 17.48%), anxiety(101, 10.70%), alteration in nutrition(83, 8.79%) , sleep disturbance (67, 7.10%), in activity intolerance (67, 7.10%), ineffective breathing pattern(51,5.40%). The etiology for the students' nursing diagnoses were compared with NANDA's nursing diagnoses by frequency. The most frequent etiology for the nursing diagnoses of pain was a biological etiology(50, 31%), for anxiety, situation crisis(58, 57.43%), for alteration in nutrition, indigesion(23, 27.71%), for sleep disturbance, external etiology(25, 37.32%), for activity intolerance, immobile position(22, 32.84%), for ineffective breathing pattern, pain(35, 68.63%), and for ,impaired physical mobility, pain(31, 65.96%). The most frequent etiology for constipation was inadquate digestion of water and cellulose (16, 34.78%), for fluid volume felicity, loss of body fluid (21, 52.50%), for impaired skin integrity, external etilogy(16, 43.24%), for impaired physical mobility, pain(22, 62.86%) , for knowledge deficits, cognition disturbance(9, 27.27％), for ineffective air way clearance, secretion obstruction(14, 48.27%) , for impaired gas exchange, loss of transport ability of blood oxygen(9, 37.50%) , and for powerlessness, therapy environment (5, 22.73%). The number of nursing diagnoses by pattern was exchange(16), moving(6), feeling(4), choosing(4), relating(3), communication(1), perceiving(1), knowing(1), valuing(1).

• Molecules and Cells
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• v.37 no.11
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• pp.767-776
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• 2014

Alzheimer's disease (AD) is clinically characterized with progressive memory loss and cognitive decline. Synaptic dysfunction is an early pathological feature that occurs prior to neurodegeneration and memory dysfunction. Mounting evidence suggests that aggregation of amyloid-${\alpha}$ ($A{\alpha}$) and hyperphosphorylated tau leads to synaptic deficits and neurodegeneration, thereby to memory loss. Among the established genetic risk factors for AD, the ${\varepsilon}4$ allele of apolipoprotein E (APOE) is the strongest genetic risk factor. We and others previously demonstrated that apoE regulates $A{\alpha}$ aggregation and clearance in an isoform-dependent manner. While the effect of apoE on $A{\alpha}$ may explain how apoE isoforms differentially affect AD pathogenesis, there are also other underexplored pathogenic mechanisms. They include differential effects of apoE on cerebral energy metabolism, neuroinflammation, neurovascular function, neurogenesis, and synaptic plasticity. ApoE is a major carrier of cholesterols that are required for neuronal activity and injury repair in the brain. Although there are a few conflicting findings and the underlying mechanism is still unclear, several lines of studies demonstrated that apoE4 leads to synaptic deficits and impairment in long-term potentiation, memory and cognition. In this review, we summarize current understanding of apoE function in the brain, with a particular emphasis on its role in synaptic plasticity and the underlying cellular and molecular mechanisms, involving low-density lipoprotein receptor-related protein 1 (LRP1), syndecan, and LRP8/ApoER2.

• Annals of Hepato-Biliary-Pancreatic Surgery
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• v.27 no.4
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• pp.366-371
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• 2023

Backgrounds/Aims: Biliary surgery in patients with extrahepatic portal vein obstruction with portal cavernoma (PC) is technically challenging, and associated with the risk of bleeding. Therefore, prior portal vein decompression is usually recommended before definitive biliary surgery. Only a few studies have so far reported the safety of isolated laparoscopic cholecystectomy. We aimed to evaluate our experience of laparoscopic cholecystectomy in patients with PC without prior portal decompression. Methods: Prospectively maintained data for patients with PC who underwent laparoscopic cholecystectomy for symptomatic gallstone disease without portal decompression were analyzed. Clinical features, imaging, intraoperative factors, conversion rate, complications of surgery, and long-term outcomes were assessed. Results: Sixteen patients underwent cholecystectomy without portal decompression from 2012 to 2021, of which interventions 14 were laparoscopic cholecystectomies. One patient required conversion (7.1%) to open surgery. Jaundice was present in 5 patients (35.7%), and underwent endoscopic stone clearance before surgery. Median intraoperative blood loss, operative time, and hospital stay were 100 mL (20-400 mL), 105 min (60-220 min), and 2 days (1-7 days), respectively. Blood transfusion was required in two patients (14.2%). Prior endoscopic or percutaneous intervention was associated with significant blood loss and prolonged intraoperative time. Conclusions: In centers with experience, prior portal decompression can be avoided in patients with PC requiring isolated cholecystectomy to treat gallstones or their complications. Laparoscopic surgery is safe and feasible for these patients, and gives excellent outcomes in the selected group.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.12
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• pp.1655-1666
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• 2003

It is experimentally well-known that high anisotropies of the turbulent flow field are dominant inside the tip leakage vortex, which is attributable to a substantial proportion of the total loss and constitutes one of the dominant mechanisms of the noise generation. This anisotropic nature of turbulence invalidates the use of the conventional isotropic eddy viscosity turbulence models based on the Boussinesq assumption. In this study, to check whether an anisotropic turbulence model is superior to the isotropic ones or not, the results obtained from the steady-state Reynolds averaged Navier-Stokes simulations based on the RNG k-$\varepsilon$ model and the Reynolds stress model (RSM) are compared with experimental data for two test cases: a linear compressor cascade and a forward-swept axial-flow fan. Through this comparative study of turbulence models, it is clearly shown that the RSM, which can express the production term and body-force term induced by system rotation without introducing any modeling, should be used to predict quantitatively the complex tip leakage flow, especially in the rotating environment.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.3
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• pp.330-337
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• 2004

Analysis of flow phenomena in a centrifugal compressor impeller has been carried out with numerical simulation to understand the physics of flow near stall. Near stall point, tip leakage flow spills ahead of the leading edge of adjacent blade and other leakage flow passes over the clearance of the adjacent blade instead of rolling up into vortex within the passage. The tip leakage flow at the mid chord of impeller blade impinges against the pressure surface of the adjacent blade and then rolls up into vortex within the passage, which blocks the flow passage and generates viscous loss. The spillage of leakage flow ahead of the adjacent blade generates the recirculation of flow entering the impeller, which causes the power transferred into the flow by the impeller to decrease and blocks the flow passage. Near diffuser hub wall, flow recirculation occurs. As operating point goes to stall point, the core of recirculation approaches the impeller exit The length rises to peak point and then drops with mass flow reduction, while the height steadily rises.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.12
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• pp.2315-2327
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• 1992

A robot assembly method which uses configuration and force/torque information of tactile sensor system and performs chamferless peg-in-hole tasks is suggested and experimentally studied. When the robot gripes the peg with random orientation, the realignment of the peg to the hole center line is successfully performed with the gripping configuration information of the tactile sensor and the inverse kinematics of the robot. The force/torque information of the tactile sensor makes it possible to control the contacting force between mating parts during hole search stage. The suggested algorithm employs a hybrid position/force control and the experiments show that the algorithm accomplishes well peg-in-hole tasks with permissible small contacting force. The chamferless peg-in-hole tasks with smaller clearance than the robot repeatibility can be excuted without any loss or deformation of mating parts. This study the possibility of precise and chamferless parts mating by robot and tactile sensor system.

• International Journal of Naval Architecture and Ocean Engineering
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• v.8 no.1
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• pp.110-116
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• 2016

In this study an attempt has been made to study the hydrodynamic performance of pumpjet propulsor. Numerical investigation based on the Reynolds Averaged NaviereStokes (RANS) computational fluid dynamics (CFD) method has been carried out. The structured grid and SST ${\kappa}-{\omega}$ turbulence model have been applied. The numerical simulations of open water performance of marine propeller E779A are carried out with different advance ratios to verify the numerical simulation method. Results show that the thrust and the torque are in good agreements with experimental data. The grid independent inspection is applied to verify accuracy of numerical simulation grid. The numerical predictions of hydrodynamic performance of pumpjet propulsor are carried out with different advance ratios. Results indicate that the rotor provides the main thrust of propulsor and the balance performance of propulsor is generally satisfactory. Additionally, the curve of propulsor efficiency is in good agreement with experimental data. Furthermore, the pressure distributions around rotor and stator blades are reasonable. Beyond that, the existence of tip clearance accounts for the appearance of tip vortex that leads to a further loss in efficiency and a probability of cavitation phenomenon.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.904-909
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• 2009

In this paper, a rolling piston rotary compressor having a combined vane and roller unit has been introduced. In a conventional rotary compressor, sliding motion takes place between the vane nose and roller. By combining the vane and the roller in one unit, gas leakage through a clearance between the vane nose and the roller can be eliminated, and the frictional loss between them can also be reduced to almost nought. Compressor model with the combined vane and roller has been fabricated and tested in a compressor calorimeter and computer simulation program has been developed to confirm merits of the new mechanism. In a test, cooling capacity has been found to be increased by 1.4%, and the compressor input decreased by 0.3%, resulting in 1.7% increased in EER. Simulation program confirmed the calorimeter test results and the merits of the new model as mentioned above.

• Clinical and Experimental Pediatrics
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• v.48 no.2
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• pp.224-227
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• 2005

Henoch-$Sch{\ddot{o}}nlein$ purpura(HSP) is an IgA mediated immune complex vasculitic disease characterized by non-thrombocytic purpura, arthritis, gastrointestinal manifestations, and glomerulonephritis. HSP related glomerulonephritis induces hypoproteinemia and edema in some cases. Protein-losing enteropathy is another rare but known manifestation of HSP leading to hypoproteinemia and edema. We report a 6-year-old girl with HSP who showed edema caused by intestinal protein loss, evidenced by elevated fecal alpha 1 antitrypsin clearance.