• 한국간담췌외과학회지
• /
• 제28권2호
• /
• pp.115-124
• /
• 2024

To compare the outcomes of low central venous pressure (CVP) to standard CVP during laparoscopic liver resection. The study design was a systematic review following the PRISMA statement standards. The available literature was searched to identify all studies comparing low CVP with standard CVP in patients undergoing laparoscopic liver resection. The outcomes included intraoperative blood loss (primary outcome), need for blood transfusion, mean arterial pressure, operative time, Pringle time, and total complications. Random-effects modelling was applied for analyses. Type I and type II errors were assessed by trial sequential analysis (TSA). A total of 8 studies including 682 patients were included (low CVP group, 342; standard CVP group, 340). Low CVP reduced intraoperative blood loss during laparoscopic liver resection (mean difference [MD], -193.49 mL; 95% confidence interval [CI], -339.86 to -47.12; p = 0.01). However, low CVP did not have any effect on blood transfusion requirement (odds ratio [OR], 0.54; 95% CI, 0.28-1.03; p = 0.06), mean arterial pressure (MD, -1.55 mm Hg; 95% CI, -3.85-0.75; p = 0.19), Pringle time (MD, -0.99 minutes; 95% CI, -5.82-3.84; p = 0.69), operative time (MD, -16.38 minutes; 95% CI, -36.68-3.39; p = 0.11), or total complications (OR, 1.92; 95% CI, 0.97-3.80; p = 0.06). TSA suggested that the meta-analysis for the primary outcome was not subject to type I or II errors. Low CVP may reduce intraoperative blood loss during laparoscopic liver resection (moderate certainty); however, this may not translate into shorter operative time, shorter Pringle time, or less need for blood transfusion. Randomized controlled trials with larger sample sizes will provide more robust evidence.

• Wind and Structures
• /
• 제27권2호
• /
• pp.111-121
• /
• 2018

Experiments were conducted in a large-scale Ward-type tornado simulator to study tornado-like vortices. Both flow velocities and the pressures at the surface beneath the vortices were measured. An interpretation of these measurements enabled an assessment of the mean flow field as well as the mean and fluctuating characteristics of the surface pressure deficit, which is a manifestation of the flow fluctuation aloft. An emphasis was placed on the effect of the aspect ratio of the tornado simulator on the characteristics of the simulated flow and the corresponding surface pressure deficit, especially the evolution of these characteristics due to the transition of the flow from a single-celled vortex to a two-celled vortex with increasing swirl ratio.

• Journal of Preventive Medicine and Public Health
• /
• 제44권4호
• /
• pp.157-166
• /
• 2011

Objectives: This study was conducted to show the intraocular pressure (IOP) distribution and the factors affecting IOP in subjects with type 2 diabetes mellitus (DM) in India. Methods: We measured the anthropometric and biochemical parameters for confirmed type 2 DM patients. A comprehensive ocular examination was performed for 1377 subjects aged > 40 years and residing in Chennai. Results: A significant difference in IOP (mean ${\pm}$ standard deviation) was found between men and women ($14.6{\pm}2.9$ and $15.0{\pm}2.8$ mmHg, p = 0.005). A significantly elevated IOP was observed among smokers, subjects with systemic hypertension and women with clinically significant macular edema (CSME). After a univariate analysis, factors associated significantly with higher IOP were elevated systolic blood pressure, elevated resting pulse rate and thicker central corneal thickness (CCT). In women, elevated glycosylated hemoglobin was associated with a higher IOP. After adjusting for all variables, the elevated resting pulse rate and CCT were found to be associated with a higher IOP. Conclusions: Systemic hypertension, smoking, pulse rate and CCT were associated with elevated intraocular pressure in type 2 DM. Women with type 2 DM, especially those with CSME, were more prone to have an elevated IOP.

• Geomechanics and Engineering
• /
• 제17권6호
• /
• pp.515-525
• /
• 2019

The calculation of active earth pressure behind retaining wall is a typical three-dimensional (3D) problem with spatial effects. With the help of limit analysis, this paper firstly deduces the internal energy dissipation power equations and various external forces power equations of the 3D retaining wall under the nonlinear strength condition, such as to establish the work-energy balance equation. The pseudo-static method is used to consider the effect of earthquake on active earth pressure in horizontal state. The failure mode is a 3D curvilinear cone failure mechanism. For the different width of the retaining wall, the plane strain block is inserted in the symmetric plane. By optimizing all parameters, the maximum value of active earth pressure is calculated. In order to verify the validity of the new expressions obtained by the paper, the solutions are compared with previously published solutions. Agreement shows that the new expressions are effective. The results of different parameters are given in the forms of figures to analysis the influence caused by nonlinear strength parameters.

• 천문학회보
• /
• 제46권1호
• /
• pp.28.2-28.2
• /
• 2021

We investigate the impact of ram pressure stripping due to the intracluster medium (ICM) on star-forming disk galaxies with a multiphase interstellar medium maintained by strong stellar feedback. We carry out radiation-hydrodynamic simulations of an isolated disk galaxy embedded in a 1011 M⦿ dark matter halo with various ICM winds mimicking the cluster outskirts (moderate) and the central environment (strong). We find that both star formation quenching and triggering occur in ram pressure-stripped galaxies, depending on the strength of the winds. HI and H2 in the outer galactic disk are significantly stripped in the presence of moderate winds, whereas turbulent pressure provides support against ram pressure in the central region, where star formation is active. Moderate ICM winds facilitate gas collapse, increasing the total star formation rates by ~40% when the wind is oriented face-on or by ~80% when it is edge-on. In contrast, strong winds rapidly blow away neutral and molecular hydrogen gas from the galaxy, suppressing star formation by a factor of 2 within ~200 Myr. Dense gas clumps with nH≳10 M⦿ pc-2 are easily identified in extraplanar regions, but no significant young stellar populations are found in such clumps. In our attempts to enhance radiative cooling by adopting a colder ICM of T=106K only a few additional stars are formed in the tail region, even if the amount of newly cooled gas increases by an order of magnitude.

• Elastomers and Composites
• /
• 제52권4호
• /
• pp.317-325
• /
• 2017

Molding conditions can be described as factors that determine the quality of a product obtained from injection molding. Many studies have been performed on the injection molding pressure, injection temperature, packing pressure and other molding conditions related to part quality. However, the most accessible factor among the adjustable molding conditions during actual injection is the injection speed. In this study, we simulated the variation of the physical quantity according to injection speed and performed experiments to understand the effect of injection speed on the actual product. A CAE analysis program (Moldflow) was used to simulate and analyze the results using PC and PBT for two models. In order to compare these results with the experimental results, an actual injection molding was performed for each injection speed, and the correlation between simulation and injection molding, especially for the shrinkage of the molded article, was discussed.

• The Korean Journal of Physiology
• /
• 제26권1호
• /
• pp.69-74
• /
• 1992

Central cardiovascular effects of bradykinin were examined in anesthetized normotensive (NTR) and 2-kidney, 1 clip Goldblatt hypertensive rats (GHR). Bradykinin ($0.5{\sim}10nmol$) was administered into the right lateral cerebral ventricle, while blood pressure and heart rate (HR) were continuously monitored. In both NTR and GHR, intracerebroventricular bradykinin produced a dose dependent increase in mean arterial pressure (MAP) without significant changes in HR. GHR were more sensitive in the pressor response than NTR. The pressor response to bradykinin was attenuated by treatment with hexamethonium (2.5mg/kg/min, IV) or phentolamine (2mg/kg, IV) in both NTR and GHR. Reserpine treatment (2mg/kg/day, intramuscularly,2 days) did not affect the central pressor effect of bradykinin in NTR but it attenuated the pressor effect in GHR. Pretreatment with indomethacin (10mg/kg, intraperitoneally) or saralasin ($20{\mu}g$/kg/min, IV) was without effects on the pressor response to bradykinin. These results indicate that the central pressor effect of bradykinin is, at least in part, due to excitation of the autonomic nervous activity. Mechanisms other than the enhanced sympathetic nervous activity ran. not be ruled out, However. It is also suggested that the sensitivity to bradykinin is increased in the GHR.

• Structural Engineering and Mechanics
• /
• 제73권5호
• /
• pp.599-612
• /
• 2020

A combination of a gravity wall and an anchor beam is widely used to support the high soil deposit on rock mass. In this study, two groups of shaking table test were performed to investigate the responses of such combined retaining structure, where the rock masses were shaped with a flat surface and a curved surface, respectively. Meanwhile, the dynamic numerical analysis was carried out for a comparison or an extensive study. The results were studied and compared between the combined retaining structures with different shaped rock masses with regard to the acceleration response, the earth pressure response, and the axial anchor force. The acceleration response is not significantly influenced by the surface shape of rock mass. The earth pressure response on the combined retaining structure with a flat rock surface is more intensive than the one with a curved rock surface. The anchor force is significantly enlarged by seismic excitation with a main earthquake-induced increment at the first intensive pulse of Wenchuan motion. The value of anchor force in the combined retaining structure with a flat rock surface is generally larger than the one with a curved rock surface. Generally, the combined retaining structure with a curved rock surface presents a better seismic performance.

• Nuclear Engineering and Technology
• /
• 제56권4호
• /
• pp.1385-1397
• /
• 2024

Bentonite is a recommended material for the multiple barriers in the final disposal of low-level radioactive waste (LLW) to prevent groundwater intrusion and nuclear species migration. However, after drying-wetting cycling during the repository construction stage and ion exchange with the concrete barrier in the long-term repository, the bentonite mechanical behaviors, including swelling capacity and hydraulic conductivity, would be further influenced by the groundwater intrusion, resulting in radioactive leakage. To comprehensively examine the factors on the mechanical characteristics of bentonite, this study presented scenarios involving MX-80 and KV-1 bentonites subjected to drying-wetting cycling and accelerated ion migration. The experiments subsequently measured free swelling, swelling pressure, and hydraulic conductivity of bentonites with intrusions of seawater, high pH, and low pH solutions. The results indicated that the solutions caused a reduction in swelling volume and pressure, and an increase in hydraulic conductivity. Specifically, the swelling capability of bentonite with drying-wetting cycling in the seawater decreased significantly by 60%, while hydraulic conductivity increased by more than three times. Therefore, the study suggested minimizing drying-wetting cycling and preventing seawater intrusion, ensuring a long service life of the multiple barriers in the LLW repository.

• 소성∙가공
• /
• 제21권5호
• /
• pp.291-297
• /
• 2012

In this paper, the effect of back tension in multi-pass drawing or wiredrawing on the central bursting defect is investigated using finite element predictions. A rigid-plastic finite element method was used together with the McClintock damage model. Central bursting defects under different back tension stress values ranging from 0% to 20% of the yield strength of the material were predicted and they were compared to understand the effect of the back tension stress values on the central bursting defect. It is found that the level of back tension has a strong influence on the cumulative damage. Thus, higher back tension raises the possibility of the central bursting defect occurring, even though it decreases the interfacial pressure between the die and the work piece.