• Membrane Journal
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• v.34 no.2
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• pp.154-162
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• 2024

Anion exchange membranes (AEMs) are essential components in water electrolysis systems, serving to physically separate the generated hydrogen and oxygen gases while enabling the selective transport of hydroxide ions between electrodes. Key characteristics sought in AEMs include high ion conductivity and robust chemical and mechanical stability in alkaline. In this study, quaternized Poly(terphenyl piperidinium)/cellulose nanocrystals (qPTP/CNC) mixed matrix membrane was fabricated. The polymer matrix, PTP, was synthesized via super-acid polymerization, known for its excellent ion conductivity and alkaline durability. The qPTP/CNC membrane showed a dense and uniform morphology without significant voids or large aggregates at the polymer-nanoparticle interface. The qPTP/CNC membrane containing 2 wt% CNC demonstrated a high ion exchange capacity of 1.90 mmol/g, coupled with low water uptake (9.09%) and swelling ratio (5.56%). Additionally, the qPTP/CNC membrane showed significantly lower resistance and superior alkaline stability (384 hours at 50℃ in 1 M KOH) compared to the commercial FAA-3-50 membrane. These results highlight the potential of hydrophilic additive CNC in enhancing ion conductivity and alkaline durability of ion exchange membranes.

• Journal of Animal Science and Technology
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• v.54 no.2
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• pp.95-101
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• 2012

The objective of this study was to examine the effect of amides as a cryoprotectant for semen cryopreservation in Korean Jeju Black Bull. The semen was cryopreserved with extenders containing 5% dimethyl acetamide (DMA), 5% dimethyl formamide (DMF), 5% methyl formamide (MF) or 7% glycerol. Post-thawed sperm were evaluated for sperm motility, viability, acrosome integrity and membrane integrity. Post-thawed sperm motility was significantly higher (p<0.05) in glycerol and DMF ($64.00%{\pm}9.62$ and $59.00%{\pm}5.48$, respectively) than DMA and MF ($50.00%{\pm}3.24$ and $44.00%{\pm}4.18$, respectively). Sperm viability wassignificantly higher (p<0.05) in glycerol and DMF ($58.25%{\pm}7.35$ and $53.05%{\pm}3.77$, respectively) than others. However, for sperm motility and viability, there were no differences among glycerol and DMF. Also, swelling sperm ratio by hypo-osmetic selling test (HOST) was significantly increased (p<0.05) in glycerol and DMF treatments ($45.12%{\pm}25.08$ and $44.95%{\pm}8.58$, respectively). The percentage of capacitated sperm assessed by CTC staining, F pattern was lower (p<0.05) in DMF than others. B pattern was increased (p<0.05) in DMA, DMF and MF when compared with glycerol. AR pattern ratio was decreased (p<0.05) in glycerol and DMF when compared with DMA and MF. These results suggested that amides performed better and could be used as a cryoprotectant for semen freezing of Korean Jeju Black Bull.

• Korean Journal of Head & Neck Oncology
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• v.9 no.1
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• pp.3-9
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• 1993

The benficial effects for perfusion in the preservation of free flaps have been controversial in the clinical and experimental field until now. This study was undertaken to observe the effect of UW solution. a recently developed. high molecular weight. organ perfusion solution. for protection of ischemic injury in normothermic free myocutaneous flaps. Forty rabbits were used in this sutdy. A 1x2x1cm sized gastrocnemius myocutaneous flap based on the feeding vessel from common femoral artery was made. The author set up the ischemic time for 12 hours in these flaps. The flap was washed out with normal saline(control grop, n=10), urokinase(comparative group I, n=10), UW solution before ischemic time(comparative group II, n=10) and UW solution before ischemic time and pentoxifylline before reperfusion(comparative group III, n=10). Afterthen, reperfusion was made for 12 hours. After this procedure, we checked the degree of ischemia and necrosis of myocutaneous flap by gross finding, electrical stimulation test of muscle, triphenyltetrazolium chloride staining and wet/dry weight ratio. The degree of necrosis of comparative group II and III were lesser than control and urokinase group in gross finding(p<0.05). In the electrical stimulation test of muscle, there was no statistical difference between control($1.76{\pm}1.01$) and urokinase($2.36{\pm}\1.02$) group however the muscular power of comparative group II($3.54{\pm}0.93$) and III($3.49{\pm}1.37gm/mm^2$) demonstrated significantly higher than control group(p<0.05). The ischemic findings were found in seven cases of control group and three cases of urokinase group but there were no ischemic findings in comparative group II and III in TIC stain(p<0.05). In the wet/dry weight ratio of flaps in order to evaluate the tissue edema. there was no statistical difference between control($4.55{\pm}0.29$) and III($3.75{\pm}0.48$) were scored significantly lesser than control and urokinase group (p<0.05). These results suggest that perfusion washout with UW solution improves the viability of normothermic free myocutaneous flap by inhibition of cellular swelling.

• Korean journal of food and cookery science
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• v.11 no.1
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• pp.69-76
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• 1995

This study was concentrated on the subject of chou formation and physicochemical characteristics on medium flour mixed with 0, 25, 50, 75, 100% of rice flour in order to clarify the possibility to substitute rice flour for wheat flour on chou preparation. The water holding capacity, swelling power, and maximum viscosity were higher in rice flour than those in medium flour but the initial pasting temperature was equal to 65$^{\circ}C$ in the two flour groups. The ratio of setback during cooling became 0.94 in the rice flour and 1.14 in the medium flour. So, the rice flour showed a slow tendency during gel formation as compared with the medium flour. The volumes of the rice choux were ranged from 80.0% to 89.0% according to the mixing ratio of medium flour as compared with that of the chou of wheat flour. But, the choux formation were increased as much as 108.8% out the paste added gelation of glutinous substance and 124.4% at the paste added Span20 of emulsifier compared to the non-addition treatment. The paste of rice flour added gelatin and Span20 showed better dispersion of components, especially, the small granules of lipid were fairly or plentifully dispersed in the paste added Span20 due to emulsifying activity. In sensory evaluation, the chou of l00% rice flour was inferior to that of medium flour on cavity-forming but the choux of wheat flour mixed with 25%, 50%, and 75% of rice flour were equal or superior to that of medium flour on all characteristics tested such as appearance, surface color, cavity-forming, chewiness, and taste. There were no significant differences on the cavity-forming expansion and taste between choux of rice flour and wheat flour Therefore, the results of this study made conclusion that rice flour would be substituted for wheat flour on the chou preparation.

• Pediatric Infection and Vaccine
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• v.6 no.2
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• pp.239-244
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• 1999

Purpose : In 1998, there was an outbreak of mumps in Taejon, Korea. We analyzed the monthly incidence, clinical manifestations, and complications during the outbreak and the annual incidence of the recent ten years. Methods : We reviewed the clinical records of 35 mumps patients who had been admitted to Taejon St. Mary's Hospital from January to December, 1998. Results : Mumps was prevalent in summer(from June to August) with 20 cases(57%). Thirthy-three patients(94.3%) received MMR at 15 months of age and no patients received a booster mumps vaccine. The mean age of the mumps patients was 10.5 years-old and the majority of mumps(71%) occurred between 5 and 12 year of age. The male female ratio was 2.2 : 1. The clinical manifestations were swelling of parotid gland(100%), fever (91%), vomiting(77%), abdominal pain(74%) and headache(66%) in order of frequency. Meningitis occurred in 20 cases(57%) and the mean WBC count of CSF was $464{\pm}263/mm^3$. In serology, the mean serum amylase level was $483{\pm}294IU/dL$ and anti-mumps IgM and IgG were positive in 11 and 15 out of 18 cases, respectively. From 1989 to 1997, the mean number of inpatients with mumps was 3.4 per year. Conclusion : We experienced an outbreak of mumps in 1998. It is suggested that there was a primary mumps vaccine failure in Korea and that further studies for vaccine faiure and method of booster mumps vaccine are necessary.

• Clinical and Experimental Pediatrics
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• v.48 no.1
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• pp.63-67
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• 2005

Purpose : Henoch-$Sch{\ddot{o}}nlein$ purpura(HSP) is a systemic vasculitis, characterized by cutaneous palpable purpura, gastrointestinal(GI) symptoms, arthritis and renal involvement. In general, the prognosis is determined by GI complication as well as the severity of nephritis. In this study, we analyzed the statistical relationship between the GI symptom and other clinical findings for assessing the prognosis, and evaluated abdominal ultrasonographic findings for early diagnosis of this disease with atypical clinical presentation and early detection of serious GI complications. Methods : One hundred seventy seven patients with HSP in the Department of Pediatrics, Wonkwang University Hospital from January 1994 to June 2004, were enrolled. We retrospectively analyzed charts about clinical and abdominal ultrasonographic findings, and classified our patients into two groups(GI-Sx(-), GI-Sx(+)) for statistical analysis. Results : The ratio of female to male is 1.5 : 1. The peak age incidence was five to eight years in 95 cases(53%). The GI symptoms appeared in 117 cases(66%), which include abdominal pain 115 (98 %), tenderness 45(38%), nausea and vomiting 35(30%), bloody stool 10(8.5%), diarrhea four(3.4%), rebound tenderness four(3.4%), and also intussusception and appendicitis were complicated in five and two cases respectively. GI-Sx(+) group had an increased risk of renal involvement and relapse than the GI-Sx(-) group. But there were no relationships about sex and age incidence, or other clinical and laboratory findings between two groups. Ultrasonographic findings in 98 patients with GI symptoms included small bowel thickening in 70 cases(71%) in which duodenum, jejunum and ileum were involved in 71%, 45.7%, 40% respectively, small bowel dilatation in 41 cases(42%), lymph node swelling in 46 cases(47%), and ascites in 25 cases(25.5%). Conclusion : GI symptoms in patients with HSP suggested increased risk of renal involvement and relapse. Abdominal ultrasonography could be helpful in the early diagnosis on atypical clinical presentation and early detection of serious GI complication in these patients.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.5
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• pp.618-625
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• 2018

With the passing of time, exposed concrete structures are affected by a range of environmental, chemical, and physical factors. These factors seep into the concrete and have a deleterious influence compared to the initial performance. The importance of identifying and preventing further performance degradation due to the occurrence of deterioration has been greatly emphasized. In recent years, evaluations of the target life have attracted increasing interest. During the freezing-melting effect, a part of the concrete undergoes swelling and shrinking repeatedly. At these times, chloride ions present in seawater penetrate into the concrete, and accelerate the deterioration due to the corrosion of reinforced bars in the concrete structures. For that reason, concrete structures located onshore with a freezing-melting effect are more prone to this type of deterioration than inland structures. The aim of this study was to develop a high performance mortar mixed with a mineral admixture for the durability properties of concrete structures near sea water. In addition, experimental studies were carried out on the strength and durability of mortar. The mixing ratio of the silica fume and meta kaolin was 3, 7 and 10 %, respectively. Furthermore, the ultra-fine fly ash was mixed at 5, 10, 15, and 20%. The mortar specimens prepared by mixing the admixtures were subjected to a static strength test on the 1st and 28th days of age and degradation acceleration tests, such as the chloride ion penetration resistance test, sulfuric acid resistance test, and salt resistant test, were carried out at 28 days of age. The chloride diffusion coefficient was calculated from a series of rapid chloride penetration tests, and used to estimate the life time against corrosion due to chloride ion penetration according to the KCI, ACI, and FIB codes. The life time of mortar with 10% meta kaolin was the longest with a service life of approximately 470 years according to the KCI code.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.4 no.2
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• pp.117-131
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• 2006

A coupled T-H-M(Thermo-Hydro-Mechanical) analysis was carried out for KENTEX (KAERI Engineering-scale T-H-M Experiment for Engineered Barrier System), which is a facility for validating the coupled T-H-M behavior in the engineered barrier system of the Korean reference HLW(high-level waste) disposal system. The changes of temperature, water saturation, and stress were estimated based on the coupled T-H-M analysis, and the influence of the types of mechanical constitutive material laws was investigated by using elastic model, poroelastic model, and poroelastic-plastic model. The analysis was done using ABAQUS, which is a commercial finite element code for general purposes. From the analysis, it was observed that the temperature in the bentonite increased sharply for a couple of days after heating the heater and then slowly increased to a constant value. The temperatures at all locations were nearly at a steady state after about 37.5 days. In the steady state, the temperature was maintained at $90^{\circ}C$ at the interface between the heater and the bentonite and at about $70^{\circ}C$ at the interface between the bentonite and the confining cylinder. The variation of the water saturation with time in bentonite was almost same independent of the material laws used in the coupled T-H-M processes. By comparing the saturation change of T-H-M and that of H-M(Hydro-Mechanical) processes using elastic and poroelastic material mod31 respectively, it was found that the degree of saturation near the heater from T-H-M calculation was higher than that from the coupled H-M calculation mainly because of the thermal flux, which seemed to speed up the saturation. The stresses in three cases with different material laws were increased with time. By comparing the stress change in H-M calculation using poroelasetic and poroelasetic-plastic model, it was possible to conclude that the influence of saturation on the stress change is higher than the influence of temperature. It is, therefore, recommended to use a material law, which can model the elastic-plastic behavior of buffer, since the coupled T-H-M processes in buffer is affected by the variation of void ratio, thermal expansion, as well as swelling pressure.

• Journal of Chest Surgery
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• v.40 no.7 s.276
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• pp.480-484
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• 2007

Background: Major vascular injuries can jeopardize a patient's life or imperil limb survival. We performed this study to establish an optimal management plan for vascular injuries. Material and Method: We retrospectively reviewed 26 cases of vascular injury that were treated at Pusan National University Hospital from May, 1999 to September, 2004. The age and sex distribution, the locations and causes of vascular injury, the diagnostic tools, the degree of injuries, clinical manifestations, the treatment modality and complications were reviewed. Result: The mean age was 39.5 years (range: $12{\sim}86$) and the male to female ratio was 22 : 4. The injuries were in 6 descending thoracic aortas, 4 femoral arteries, 4 popliteal veins and so on. The causes of injury were iatrogenic in 8 cases, traffic accident in 7, stab injury in 6 and industrial accident in 5. The most commonly used diagnostic tools were CT and angiography. The degrees of arterial injury were pseudoaneurysm in 10 cases, partial severance in 5, complete severance in 3 and thrombosis in 3. The degrees of venous injury were partial severance in 6 cases, complete severance in 2 and arteriovenous fistula in 2. The clinical manifestations were absence of pulse in 8 cases, coldness in 7, chest pain in 6, swelling in 5, bleeding in 5 and so on. The most frequently used type of revascularization was graft interposition in 11 cases. Two arteriovenous fistulae were repaired by endovascular procedure. There was one case of mortality due to multi-organ failure after hemorrhagic shock, There were three major amputations, and two of them were due to delayed diagnosis and treatment. Conclusion: A system for the early diagnosis and treatment is essential for improving limb salvage and patient mortality. As a consequence of the widespread application of endovascular procedures, the incidence of iatrogenic injuries has recently increased. Educating physicians is important for the prevention of iatrogenic injury. Easy communication and cooperation for earlier involvement of a vascular surgeon is also an important factor.

• The Korean Journal of Nuclear Medicine Technology
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• v.17 no.2
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• pp.90-94
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• 2013

Purpose: In the PET/CT images, various artifacts cause degradation of the quantitative assessment. Most hotspot generated by radiopharmaceutical injection errors cause an artifact and degrade the quality of the images as well as the accuracy of the quantitative evaluation. The purpose of this study is to assess effectiveness of the elimination of the hotspot at the injection sites using shifting the center of DFOV (Display Field of View, DFOV) method and evaluate the quantitative evaluation of result. Materials and Methods: GE Discovery STE 16 (GE Healthcare, Milwaukee, USA) and 1994 NEMA phantom were used for imaging acquisition. Phantom was filled with 0.005 MBq/mL of $^{18}F-FDG$. A hotspot was artificially placed on the outside of the phantom. The ratio of hotspot area activity to background area activity was regulated as 200:1. After image acquisition with routine protocol, all of the images were reconstructed using the shifting the center of DFOV method that wasn't overlapped with hotspot. Those images obtained before and after applying the shifting reconstruction method were compared. ROIs (Region Of Interests) were set in the hotspot areas, meanSUVs and standard deviations were calculated. Percentage differences were calculated with those meanSUVs and standard deviations. The evaluation on the effects of the shifting reconstruction method was done by comparison of the meanSUVs and the standard deviations, which were calculated for background areas unaffected by hotspot. Results: In the areas of unaffected by hotspot, meanSUVs before and after applying the shifting of center of DFOV method were $0.67{\pm}0.06g/mL$ and $0.65{\pm}0.06g/mL$, respectively. In the artifact areas affected by hotspot, meanSUVs before and after applying the shifting of center of DFOV method were $0.32{\pm}0.08g/mL$ and $0.56{\pm}0.12g/mL$, respectively. The percentage differences of the area adjacent to the hotspot and the area distant from the hotspot were 65.3% and 97.4%, respectively. Conclusion: In the PET/CT images, meanSUV was improved by 32.1% when the effect of artifact was removed with application of the shifting the center of DFOV methode. In other areas unaffected by artifacts, meanSUVs were not significantly different after applying DFOV center shift method. As shown in the result, adverse effects of hotspot made by swelling in the injection site can be reduced by applying DFOV center shift method. Therefore, DFOV center shift method can be applied for the more precise quantitative evaluation, and contribute to the increase of the diagnostic value of the images.