• Journal of The Korean Ophthalmological Society
• /
• v.59 no.12
• /
• pp.1173-1180
• /
• 2018

Purpose: We evaluated the postoperative accuracy of intraocular lens power prediction for patients undergoing phacotrabeculectomy and identified preoperative factors associated with refractive outcome in those with primary open-angle glaucoma (POAG). Methods: We retrospectively reviewed the medical records of 27 patients who underwent phacotrabeculectomy to treat POAG. We recorded all discrepancies between predicted and actual postoperative refractions. We compared the data to those of an age- and sex-matched control group that underwent uncomplicated cataract surgery during the same time period. Preoperative factors associated with the mean absolute error (MAE) were identified via multivariate regression analyses. Results: The mean refractive error of the 27 eyes that underwent phacotrabeculectomy was comparable to that of the 27 eyes treated via phacoemulsification (+0.02 vs. -0.01 D, p = 0.802). The phacotrabeculectomy group exhibited a significantly higher MAE (0.65 vs. 0.35 D, p = 0.035) and more postoperative astigmatism (-1.07 vs. -0.66 D, p = 0.020) than the phacoemulsification group. The preoperative anterior chamber depth (ACD) and the changes in the postoperative intraocular pressure (IOP) were significantly associated with a greater MAE after phacotrabeculectomy. Conclusions: POAG treatment via combined phacoemulsification/trabeculectomy was associated with greater error in terms of final refraction prediction, and more postoperative astigmatism. As both a shallow preoperative ACD and a greater postoperative change in IOP appear to increase the predictive error, these two factors should be considered when planning phacotrabeculectomy.

• Clinical and Experimental Emergency Medicine
• /
• v.5 no.4
• /
• pp.219-229
• /
• 2018

Objective We compared the predictive value of the National Early Warning Score+Lactate (NEWS+L) score with those of other parameters such as the pre-endoscopic Rockall score (PERS), Glasgow-Blatchford score (GBS), and albumin, international normalized ratio, altered mental status, systolic blood pressure, age older than 65 years score (AIMS65) among patients with upper gastrointestinal bleeding (UGIB). Methods We conducted a retrospective study of patients with UGIB during 2 consecutive years. The primary outcome was the composite of in-hospital death, intensive care unit admission, and the need for ${\geq}5$ packs of red blood cell transfusion within 24 hours. Results Among 530 included patients, the composite outcome occurred in 59 patients (19 inhospital deaths, 13 intensive care unit admissions, and 40 transfusions of ${\geq}5$ packs of red blood cells within 24 hours). The area under the receiver operating characteristic curve of the NEWS+L score for the composite outcome was 0.76 (95% confidence interval, 0.70 to 0.82), which demonstrated a significant difference compared to PERS (0.66, 0.59-0.73, P=0.004), but not to GBS (0.70, 0.64-0.77, P=0.141) and AIMS65 (0.76, 0.70-0.83, P=0.999). The sensitivities of NEWS+L scores of 3 (n=34, 6.4%), 4 (n=92, 17.4%), and 5 (n=171, 32.3%) were 100%, 98.3%, and 96.6%, respectively, while the sensitivity of an AIMS65 score of 0 (n=159, 30.0%) was 91.5%. Conclusion The NEWS+L score showed better discriminative performance than the PERS and comparable discriminative performance to the GBS and AIMS65. The NEWS+L score may be used to identify low-risk patients among patients with UGIB.

• The Journal of the Petrological Society of Korea
• /
• v.1 no.2
• /
• pp.104-123
• /
• 1992

We present petrography, mineral chemistry of amphibole and plagioclase, and major and trace element chemistry for the Ogcheon metabasites occurring in the Poun and Mungyong areas to understand metamorphism, and to define chemical characteristics of parental rocks and their implication for tectonic environment. The Ogcheon metabasites often preserve relict igneous textures, although no primary phases are observed. They are mainly composed of amphibole (actinolite+hornblende)+plagioclase+epidote+chlorite+sphene+opaque oxides, indicating epidote amphibolite facies metamorphism. Coarse-grained amphiboles frequently have actinolitic composition in the core, and hornblende along the margin and cleavage, which can be interpreted either as miscibility gap or as result of polymetamorphism. Although presumed polymetamorphic events in the Ogcheon supergroup favor the latter possibility, further metamorphic studies are necessary to solve the problem. Amphibole and plagioclase chemistries suggest greenschist (epidote-amphibolite, if miscibility gap is present) to amphibolite facies metamorphism of possibly medium pressure. The major and trace element data of whole rocks indicate that the Ogcheon metabasites are transitional to tholeiitic basalts belonging to within-plate environment. Absence of evidences indicating deep sea environment suggests that the Ogcheon metabasites emplaced in an intra-cratonic, possibly rift environment which failed to proceed to an oceanic rift. Chemical variation of the metabasites toward a granitic pluton indicates K loss closer to the pluton, suggesting that caution should be taken when K is involved in a discussion.

• Journal of the Korean Institute of Gas
• /
• v.25 no.4
• /
• pp.49-56
• /
• 2021

Liquefied Petroleum Gas is divided into liquefied gases containing propane (C₃H₈) and butane (C₄H₁₀). The quality of LPG varies greatly depending on the composition of the mixture, so it is important to measure the composition accurately. It is difficult to determine the composition of the mixture because liquid and gas coexist at room temperature. Therefore, the uncertainty in determining the concentration of hydrocarbons by component is high, and there are many problems that differ from the actual content standard. Therefore, it is necessary to develop a mixed liquid propane standard gas for the composition and accurate concentration of hydrocarbon substances. Mixed liquid propane standard gas is manufactured into bellows-type constant-pressure cylinders by ISO-6142 (2015). The homogeneity of the four standard gases manufactured was confirmed to be GC-FID. The manufacturer's uncertainty of expansion was 0.01 % to 0.30 % and homogeneity was 0.03 % to 0.25 %. In this mixed liquid propane standard gas, the relative expansion uncertainty of weight method, manufacturing consistency, cylinder adsorption and long-term stability was developed within 0.26 %-1.3 9% (95% of confidence level, k=2).

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.3
• /
• pp.417-422
• /
• 2019

Hemodynamically unstable pelvic fractures show a remarkably high mortality rate of 40% to 60%. However, their standard of care remains controversial. We report here a case of a 78-year-old woman who was admitted to the Emergency Department with pelvic pain following a fall. Based on pelvic radiography, she was diagnosed with an unstable pelvic fracture. Her blood pressure was 60/40 mmHg, and owing to her unstable vital signs, emergency angiography was performed without computed tomography (CT). Both internal iliac arteries were embolized without sub-branch selection for prompt control of pelvic bleeding. Following embolization, her vital signs were stabilized. Subsequent CT revealed free intra-abdominal air, suggesting bowel perforation had occurred and necessitating emergency laparotomy. An approximately 1 cm-sized free perforation of the small intestine was identified intraoperatively, and primary closure was performed. A retroperitoneal hematoma identified intraoperatively was not explored further because it was a non-expanding and non-pulsatile mass. The patient was admitted to the Intensive Care Unit and transferred to the general ward on postoperative day 3. In this case, the hemodynamically stable pelvic fracture with bowel perforation was successfully and safely treated by prompt angioembolization without conducting CT.

• Applied Chemistry for Engineering
• /
• v.30 no.1
• /
• pp.122-131
• /
• 2019

In order to reuse and concentrate the sewage, a forward osmosis using fertilizer as draw solution was applied. Sewage-1, which is the supernatant after settling for 30 minutes for the primary settling basin influent, and Sewage-2, which is the supernatant after settling for 30 minutes for the effluent, and Sewage-3, which is the filtrate filtered through a $1{\mu}m$ cartridge filter for the effluent were tested. Eight draw solutions of $NH_4H_2PO_4$, KCl, $KNO_3$, $NH_4Cl$, $(NH_4)_2HPO_4$, $NH_4NO_3$, $NH_4HCO_3$, and $KHCO_3$ were used in consideration of osmotic pressure, solubility and pH. In the case of Sewage-3, the permeate flux was almost similar to that of the discharge water of the sewage treatment plant, and was larger than that of Sewage-1 and Sewage-2. $NH_4H_2PO_4$ was the smallest, and $NH_4NO_3$ was the largest in the specific reverse solute flux. $NH_4H_2PO_4$ was found to be most useful for the reuse and concentration of sewage because it contains nitrogen and phosphorus, which are the major components of fertilizer, as well as low specific reverse solute flux. When $NH_4H_2PO_4$ was used as the draw solution, the concentration factor after 24 hours for Sewage-3 was 1.72.

• Journal of Korea Foundry Society
• /
• v.41 no.3
• /
• pp.235-240
• /
• 2021

We present the effect of the critical cooling rate during rapid solidification on the nucleation of precipitates in an Fe₇₅B₁₃P₅Nb₂Hf₁C₄ (at.%) alloy. The thermophysical properties of the rapidly solidified Fe₇₅B₁₃P₅Nb₂Hf₁C₄ liquids, which were obtained at various cooling rates with various sizes of gas-atomized powder during a high-pressure inert gas-atomization process, were evaluated. The cooling rate of the small-particle powder (≤20 ㎛) was 8.4×10⁵ K/s, which was 13.5 times faster than that of the large-particle powder (20 to 45 mm; 6.2×10⁴ K/s) under an atomized temperature. A thermodynamic calculation model used to predict the nucleation of the precipitates was confirmed by the microstructural observation of MC-type carbide in the Fe₇₅B₁₃P₅Nb₂Hf₁C₄ alloy. The primary carbide phase was only formed in the large-particle gas-atomized powder obtained during solidification at a slow cooling rate compared to that of the small-particle powder.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.22 no.6
• /
• pp.460-468
• /
• 2021

This study investigated the enhanced combustion efficiency of an "air-cooled combustion system" with single F.D. fan, and performed a numerical analysis for the operation and design conditions to increase the combustion efficiency. The combustion efficiency in an actual combustor was compared before and after the structure modification. Numerical analysis for application of a single fan revealed the difficulty of forming a turbulence for circular combustion conditions. This is because the supply ratio of combustion air supplied into 2 flow paths becomes irregular in the combustion furnace due to a change in friction force and pressure in each flow path. Subsequently, two methods of supplying air into the combustion furnace were analyzed numerically to obtain the optimal combustion conditions of an air-cooled combustion system. The first method involved injecting the preheated combustion air after a 180~360 degree rotation from the outer wall, whereas in the second method, the combustion air was injected into the combustion furnace in a tangential direction after primary heat exchange outside the combustion furnace, by applying a rotatable vane structure in the combustion furnace. Results reveal that application of a single F.D. fan to the air injection into a rotatable combustion furnace is desirable for optimization of the combustion conditions for applying a duct structure having a dual cooling wall for the cooling of the outer wall of the combustion furnace, and for maintaining perfect mixing in the combustion furnace. We therefore confirmed enhanced combustion efficiency by comparing the actual combustion efficiency before and after structure modification.

• Physical Therapy Korea
• /
• v.28 no.1
• /
• pp.18-26
• /
• 2021

Previous studies have reported that deep neck flexor (DNF) exercise can improve neck problems, including neck pain, forward head posture, and headache, by targeting the deep and superficial muscles of the neck. Despite the prevailing opinion across studies, the benefits of DNF can vary according to the type of neck problems and the outcome measures adopted, ranging from positive outcomes to non-significant benefits. A meta-analysis was conducted in this study to assess conclusive evidence of the impact of DNF exercise on individuals with neck problems. We used PUBMED, MEDLINE, NDSL, EMBASE, and Web of Science to search for primary studies and the key terms used in these searches were "forward head posture (FHP)," "biofeedback," "pressure biofeedback unit," "stabilizer," "headache," and "neck pain." Twenty-four eligible studies were included in this meta-analysis and were coded according to the type of neck problems and outcome measures described, such as pain, endurance, involvement of neck muscle, craniovertebral angle (CVA), neck disability index (NDI), cervical range of motion (CROM), radiographs of the neck, posture, strength, endurance, and headache disability index. The overall effect size of the DNF exercise was 0.489. The effect sizes of the neck problems were 0.556 (neck pain), -1.278 (FHP), 0.176 (headache), and 1.850 (mix). The effect sizes of outcome measures were 1.045 (pain), 0.966 (endurance), 0.894 (deep neck flexor), 0.608 (superficial neck flexor), 0.487 (CVA), 0.409 (NDI), and 0.252 (CROM). According to the results of this study, DNF exercise can effectively reduce neck pain. Thus, DNF exercise is highly recommend as an effective exercise method for individuals suffering from neck pain.

• Journal of the Korean Geotechnical Society
• /
• v.38 no.11
• /
• pp.107-118
• /
• 2022

The social need for stable hydrogen storage technologies that respond to the increasing demand for hydrogen energy is increasing. Among them, underground hydrogen storage is recognized as the most economical and reasonable storage method because of its vast hydrogen storage capacity. In Korea, low-depth hydrogen storage using artificial protective structures is being considered. Further, establishing corresponding safety standards and ground stability evaluation is becoming essential. This study evaluated the hydro-mechanical behavior of the ground during a hydrogen gas leak from a low-depth underground hydrogen storage facility through the HM coupled analysis model. The predictive reliability of the simulation model was verified through benchmark experiments. A parameter study was performed using a metamodel to analyze the sensitivity of factors affecting the surface uplift caused by the upward infiltration of high-pressure hydrogen gas. Accordingly, it was confirmed that the elastic modulus of the ground was the largest. The simulation results are considered to be valuable primary data for evaluating the complex analysis of hydrogen gas explosions as well as hydrogen gas leaks in the future.