• Proceedings of the Membrane Society of Korea Conference
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• 1999.07a
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• pp.39-42
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• 1999

Perfluoropolymers represent the ultimate resistance to hostile chemical environments and high service temperature, attributed to the presence of fluorine in the polymer backbone, i.e. to the high bond energy of C-F and C-C bonds of fluorocarbons. Copolymers of Tetrafluoroethylene (TEE) and 2, 2, 4Trifluoro-5Trifluorometoxy- 1, 3Dioxole (TTD), commercially known as HYFLON AD, are amorphous perfluoropolymers with glass transition temperature (Tg)higher than room temperature, showing a thermal decomposition temperature exceeding 40$0^{\circ}C$. These polymer systems are highly soluble in fluorinated solvents, with low solution viscosities. This property allows the preparation of self-supported and composite membranes with desired membrane thickness. Symmetric and asymmetric perfluoropolymer membranes, made with HYFLON AD, have been prepared and evaluated. Porous and not porous symmetric membranes have been obtained by solvent evaporation with various processing conditions. Asymmetric membranes have been prepared by th wet phase inversion method. Measure of contact angle to distilled water have been carried out. Figure 1 compares experimental results with those of other commercial membranes. Contact angles of about 120$^{\circ}$for our amorphous perfluoropolymer membranes demonstrate that they posses a high hydrophobic character. Measure of contact angles to hexandecane have been also carried out to evaluate the organophobic character. Rsults are reported in Figure 2. The observed strong organophobicity leads to excellent fouling resistance and inertness. Porous membranes with pore size between 30 and 80 nanometers have shown no permeation to water at pressures as high as 10 bars. However high permeation to gases, such as O2, N2 and CO2, and no selectivities were observed. Considering the porous structure of the membrane, this behavior was expected. In consideration of the above properties, possible useful uses in th field of gas- liquid separations are envisaged for these membranes. A particularly promising application is in the field of membrane contactors, equipments in which membranes are used to improve mass transfer coefficients in respect to traditional extraction and absorption processes. Gas permeation properties have been evaluated for asymmetric membranes and composite symmetric ones. Experimental permselectivity values, obtained at different pressure differences, to various single gases are reported in Tab. 1, 2 and 3. Experimental data have been compared with literature data obtained with membranes made with different amorphous perfluoropolymer systems, such as copolymers of Perfluoro2, 2dimethyl dioxole (PDD) and Tetrafluorethylene, commercialized by the Du Pont Company with the trade name of Teflon AF. An interesting linear relationship between permeability and the glass transition temperature of the polymer constituting the membrane has been observed. Results are descussed in terms of polymer chain structure, which affects the presence of voids at molecular scale and their size distribution. Molecular Dyanmics studies are in progress in order to support the understanding of these results. A modified Theodoru- Suter method provided by the Amorphous Cell module of InsightII/Discover was used to determine the chain packing. A completely amorphous polymer box of about 3.5 nm was considered. Last but not least the use of amorphous perfluoropolymer membranes appears to be ideal when separation processes have to be performed in hostile environments, i.e. high temperatures and aggressive non-aqueous media, such as chemicals and solvents. In these cases Hyflon AD membranes can exploit the outstanding resistance of perfluoropolymers.

• Radiation Oncology Journal
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• v.22 no.4
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• pp.288-297
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• 2004

Puporse: The aims of this study were to evaluate the change of $[^18F]fluoromisonidazole$($[^18F]FMISO$) uptake in C3H mouse squamous cell carcinoma-VII (SCC-VII) treated with mild hyperthermia ($42^{circ}C$) and nicotinamide and to assess the biodistribution of the markers in normal tissues under similar conditions. Methods and Materials: $[^18F]FMISO$ was producedby our hospital. Female C3H mice with a C3H SCC-VII tumor grown on their extremities were used. Tumors were size matched. Non-anaesthetized, tumor-bearing mice underwent control or mild hyperthermia at $42^{circ}C$ for 60 min with nicotinamide (50 mg/kg i.p. injected) and were examined by gamma counter, autoradiography and animal PET scan 3 hours after tracer i.v. injected with breathing room air, The biodistribution of these agents were obtained at 3 h after $[^18F]FMISO$ injection. Blood, tumor, muscle, heart, lung, liver, kidney, brain, bone, spleen, and intestine were removed, counted for radioactivity and weighed. The tumor and liver were frozen and cut with a cryomicrotome into 10- um sections. The spatial distribution of radioactivity from the tissue sections was determined with digital autoradiography. Results: The mild hyperthermia with nicotinamide treatment had only slight effects on the biodistribution of either marker in normal tissues. We observed that the whole tumor radioactivity uptake ratios were higher in the control mice than in the mild hyperthermia with nicotinamide treated mice for $[^18F]FMISO$ ($1.56{\pm}1.03$ vs. $0.67{\pm}0.30$; p=0.063). In addition, autoradiography and animal PET scan demonstrated that the area and intensity of $[^18F]FMISO$ uptake was significantly decreased. Conclusion: Mild hyperthermla and nicotinamide significantly improved tumor hypoxia using $[^18F]FMISO$ and this uptake reflected tumor hypoxic status.

• Radiation Oncology Journal
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• v.13 no.3
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• pp.259-266
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• 1995

Purpose : The aim of this study is to analyze the survival rate, treatment failure and complication of radiation therapy alone in stage III uterine cervical cancer. Materials and Methods : From January 1980 through December 1985, 227 patients with stage III uterine cervical cancer treated with radiation therapy at Kosin Medical Center were retrospectively studied. Among 227 patients, 72 patients($317{\%}$) were stage IIIa, and 155 patients($68.3{\%}$) were stage IIIb according to FIGO classification. Age distribution was 32-71 years (median: 62 years). Sixty nine patients($95.8{\%}$) in stage IIIa and 150 patient ($96.8{\%}$) in stage IIIb were squamous cell carcinoma. pelvic lymph node metastasis at initial diagnosis was 8 patients($11.1{\%}$) in stage IIIa and 29 patients($18.7{\%}$) in stage IIIb, Among 72 patients with stage IIIa, 36 patients ($50{\%}$) were treated with external radiation therapy alone by conventional technique (180-200 cGy/fr.) and 36 patients($50{\%}$) were treated with external radiation therapy with intracavitary radiotherapy(ICR) with $Cs^{137}$ sources, and among 155 patients with stage IIIb, 80 patients ($51.6{\%}$) were treated with external radiation therapy alone and 75 patients ($48.4{\%}$) were treated with external radiation therapy with ICR. Total radiation doses of stage IIIa and IIIb were 65-105 Gy(median: 78.5 Gy) and 65-125.5 Gy (median 83.5 Gy). Survival rate was calculated by life-table method. Results : Complete response rates were $58.3{\%}$(42 patients) in stage IIIa and $56.1{\%}$(87 patients) in stage IIIb. Overall 5 year survival rates were $57{\%}$ in stage IIIa and $40{\%}$ in stage IIIb. Five year survival rates by radiation technique in stage IIIa and IIIb were $64{\%},\;40{\%}$ in the group treated in combination of external radiation and ICR, and $50\%,\;40\%$ in the group of external radiation therapy alone(P=NS). Five year survival rates by response of radiation therapy in stage IIIa and IIIb were $90\%,\;66\%$ in responder group and $10\%,\;7\%$ in non-responder group (P<0.001) There were statistically no significant differences of 5 year survival rate by total radiation doses and external radiation doses(40 Gy vs 50 Gy) of whole or true pelvis in stage IIIa and IIIb(P=NS). Treatment failures rates were $40.3\%$(29 patients) in stage IIla and $57.4\%$(89 patients) in stage IIIb. 17 patients ($23.6\%$) in stage IIIa and 46 patients ($29.7\%$) in stage IIIb experienced complications. Total radiation doses more than 85 Gy produced serious complication in both stage IIIa($50\%$) and IIIb($50\%$). Serious complication rates were higher in group received external radiation doses of 50 Gy than 40 Gy to whole or true pelvis in stage IIIa and IIIb. Serious rectal complication developed in rectal doses more than 65 Gy, and serious bladder complication developed in bladder doses more than 75 Gy. Major cause of death was cachexia due to locoregional failure in both stage IIIa($34.7\%$) and IIIb($43.9\%$). Conclusion : From this study, we found that external radiation therapy with ICR was found to have a tendency to be superior to external radiation therapy alone in survival rate, local control rate and complication rate but not different in statistics, and external radiation doses of 50 Gy than 40 Gy to whole or true pelvis produced serious rectal and bladder complications in stage III uterine cervical cancer.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.22 no.1
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• pp.31-44
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• 2017

Pfiesteria piscicida is one of heterotrophic dinoflagellate having toxic metaboliges, and it is difficult to detect and quantify this dinoflagellate via light microscope due to small size and morphological similarity with Pfiesteria-like dinoflagellate (PLD) species. Alternatively, we developed quantitative real-time PCR assay based on EvaGreen and determined field accessibility throughout the investigation of distribution in the entire Korean coastal waters and population dynamics in Shihwa Lake. The P. piscicida-specific primers based on internal transcribed spacer 1 (ITS 1) were designed and the specificity of primers was confirmed by PCR with other genomic DNAs which have genetic similarity with target species. Through real-time PCR assay, a standard curve which had a significant linear correlation between log cell number and $C_T$ value ($r^2{\geq}0.999$) and one informative melting peak ($88^{\circ}C$) were obtained. These results implies that developed real-time PCR can accurately detect and quantify P. piscicida. Throughout the field applications of real-time PCR assay, P. piscicida was distributed in western (Mokpo and Kimje) and easthern (Gangneng) Korean coastal water even though light microscopy failed to identify P. piscicida. In the investigation of population dynamics in Shihwa Lake, the density of P. piscicida was peaked in June, July and August 2007 at St. 1 where salinity (${\leq}15psu$) was lower than the other 2 sites. In this study, we successed to develop EvaGreen bassed real-time PCR for detection and quantification of P. piscicida in fields, so this developed assay will be useful for various ecological studies in the future.

• Journal of the Mineralogical Society of Korea
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• v.31 no.4
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• pp.235-248
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• 2018

The present work was performed in order to study the effect of competing cation of $Ca^{2+}$ ion on ion exchange of $Cs^+$ on zeolite Y (Si/Al = 1.56). Three single-crystals of fully dehydrated and partially $Cs^+$-exchanged zeolites Y (Si/Al = 1.56) were prepared by the flow method using mixed ion-exchange solutions. The $CsNO_3:Ca(NO_3)_2$ molar ratios of the ion exchange solution were 1 : 1 (crystal 1), 1 : 100 (crystal 2), and 1 : 250 (crystal 3) with a total concentration of 0.05 M. The single-crystals were then vacuum dehydrated at 723 K and $1{\times}10^{-4}Pa$ for 2 days. The structures of the crystals were determined by single-crystal synchrotron X-ray diffraction technique in the cubic space group $Fd{\bar{3}}m$, at 100(1) K. The unit-cell formulas of crystals 1, 2, and 3 were ${\mid}Cs_{21}Ca_{27}{\mid}[Si_{117}Al_{75}O_{384}]-FAU$, ${\mid}Cs_2Ca_{36.5}{\mid}[Si_{117}Al_{75}O_{384}]-FAU$, and ${\mid}Cs_1Ca_{37}{\mid}[Si_{117}Al_{75}O_{384}]-FAU$, respectively. In all three crystals, the $Ca^{2+}$ ions preferred to occupy site I in the D6Rs, with the remainder occupying sites I', II', and II. On the other hand, the significant differences in the fractional distribution of $Cs^+$ ions are observed depending on the intial $Cs^+$ concentrations in given ion exchange solution. In Crystal 1, $Cs^+$ ion are located at sites II', II, III, and III', and in crystal 2, at sites II, IIIa, and IIIb. In crystal 3, $Cs^+$ ions are only located at sites IIIa and IIIb. The degree of $Cs^+$ ion exchange decreased sharply from 28.0 to 2.7 to 1.3 % as the initial $Ca^{2+}$ concentration increases and the $Cs^+$ content decreases.

• Korean Journal of Mineralogy and Petrology
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• v.35 no.1
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• pp.41-50
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• 2022

To study the properties of Sr²⁺ exchange into zeolite A with increasing the molar concentration of Na⁺ in given exchange solution, four single crystals of fully dehydrated Sr²⁺- and Na⁺- exchanged zeolite A were prepared by the bath method using mixed ion-exchange solutions. The Sr(NO₃)₂:NaNO₃ molar rations of the ion exchange solution were 1:1(crystal 1), 1:100(crystal 2), 1:250(crystal 3), and 1:500 (crystal 4), respectively, with a total concentration of 0.05 M. The single-crystals were then vacuum dehydration at 623 K and 1×10^-4 Pa for 2 days. Their single-crystal structures were determined by single-crystal synchrotron X-ray diffraction techniques in the cubic space group Pm3-m, at 100(1) K, and were then refined to the final error indices of R₁/wR₂=0.047/0.146, 0.048/0.142, 0.036/0.128, and 0.040/0.156 for crystals 1, 2, 3, and 4, respectively. In crystals 1 and 2, the 6 Sr²⁺ ions are found at three different crystallographic sites. In crystal 3, 1 Sr²⁺ and 10 Na⁺ ions are found in large cavity and sodalite unit. In crystal 4, only 12 Na⁺ ions occupy three equipoints. The degree of Sr²⁺ ion-exchange decreased sharply from 100 to 16.7 to 0% as the initial Na⁺ concentration increase and the Sr²⁺ concentration decrease. In addition, the unit cell constant of the zeolite framework decreased with this lower level of Sr²⁺ exchange.

• Journal of the Korean Orthopaedic Association
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• v.55 no.6
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• pp.511-519
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• 2020

Purpose: Schwannoma is a benign tumor that occurs mainly in the peripheral nerve. If the tumor is large or is in areas other than the nerves, it is likely to be mistaken for malignant soft tissue tumors. The authors reviewed 50 cases of giant schwannomas and assessed the distribution of the primary locations, clinical symptoms, radiological and pathological diagnosis, and diagnostic accuracy. Materials and Methods: Of the 214 pathologically confirmed schwannomas, 50 cases with a maximum diameter of 5 cm or more were extracted. The entire cohort was classified into three subgroups (major peripheral nerve, intramuscular, bone) according to the primary location, and the anatomical locations were specified. Results: When the entire cohort was classified according to the primary location, 14 tumors occurred in the major peripheral nerve, 31 cases in the muscle, and 5 cases in the bone. The mean size of the tumor in the entire cohort was 7.0 cm, and the intramuscular subgroup had the largest size with 8.0 cm. The radiological diagnosis revealed 33 out of 50 cases to be benign schwannoma (66.0%), 15 cases as low-grade malignancy (30.0%), and the remaining two cases (4.0%) as a suspicious tuberculosis abscess and tenosynovial giant cell tumor, respectively. On the clinical symptoms, Tinel sign was the most common in the peripheral nerve group with 78.6% (11/14), while 93.5% of the intramuscular group had palpation of the mass with a mean duration of 66.6 months. In the bone group, one out of five cases was reported as a low-grade malignancy. Two cases of postoperative complications were encountered; one was bleeding after tumor excision, which required hemostasis, and the other was peroneal nerve palsy after surgery. Conclusion: When assessing the large-sized soft tissue tumors in the muscles, the possibility of a benign schwannoma should be considered if 1) there is a long period of mass palpation and 2) non-specific findings in MRI. Preoperative pathology confirmation with a biopsy can help reduce the risk of overtreatment.

• Journal of the Korean Society of Radiology
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• v.16 no.3
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• pp.335-341
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• 2022

The purpose of this study was to investigate the radiation protection effect of blueberries. The experimental animals used in this study were 8-week-old 21 SD male rats weighed 280-300 g. The animals were set to a normal group (A), a 5 Gy control group (B), and a 5 Gy experimental group (C) of seven rats each, and (50 mg/kg/day) of physiological saline solution of blueberries were orally administered twice a day with an oral dose of (200 mg/kg/day) for seven days and 5 Gy of radiation was irradiated in the case of groups B and C. As a result, it was identified that there was significance in white blood cells in this study (p<0.000). There was no significant difference in red blood cells or platelets. When examined in detail, among white blood cells (WBC), neutrocytes were found to be significantly different among the three groups: normal, control, and experimental groups (p<0.004). Lymphocytes were also found to be statistically significantly different among the three groups (p<0.000). Monocytes were not found to be statistically significantly different (p<0.483). When red blood cells (RBC) were examined, hemoglobin (HGB) was not found to be statistically significant different among the three groups (p<0.291). Hematocrit (HCT) was not found to be statistically significantly different among the three groups, either (p<0.564). Mean corpuscular volume (MCV) was found to be statistically significantly different among the three groups (p<0.001). Mean corpuscular hemoglobin (MCH) was also found to be statistically significantly among the three groups (p<0.028). Mean corpuscular hemoglobin concentration (MCHC) was found to be statistically significantly different among the three groups(p<0.020). Red blood cell distribution width (RDW) was not found to be statistically significantly different among the three groups (p<0.09). When platelets (PLT) were examined in detail, mean platelet volume (MpV) was found to be statistically significantly different among the three groups (MpV) (p<0.04). In conclusion, based on this study, blueberries are considered to have radiation protection effects.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.9 no.1
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• pp.9-16
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• 2023

Liposomes as drug delivery system have proved useful carrier for various disease, including cancer. In addition, perfluorocarbon cored microbubbles are utilized in conjunction with high-intensity focused-ultrasound (HIFU) to enable simultaneous diagnosis and treatment. However, microbubbles generally exhibit lower drug loading efficiency, so the need for the development of a novel liposome-based drug delivery material that can efficiently load and deliver drugs to targeted areas via HIFU. This study aims to develop a liposome-based drug delivery material by introducing a substance that can burst liposomes using ultrasound energy and confirm the ability to target tumors using PET imaging. Liposomes (Lipo-DOX, Lipo-DOX-Au, Lipo-DOX-Au-RGD) were synthesized with gold nanoparticles using an avidin-biotin bond, and doxorubicin was mounted inside by pH gradient method. The size distribution was measured by DLS, and encapsulation efficiency of doxorubicin was analyzed by UV-vis spectrometer. The target specificity and cytotoxicity of liposomes were assessed in vitro by glioblastoma U87mg cells to HIFU treatment and analyzed using CCK-8 assay, and fluorescence microscopy at 6-hour intervals for up to 24 hours. For the in vivo study, U87mg model mouse were injected intravenously with 1.48 MBq of ⁶⁴Cu-labeled Lipo-DOX-Au and Lipo-DOX-Au-RGD, and PET images were taken at 0, 2, 4, 8, and 24 hours. As a result, the size of liposomes was 108.3 ± 5.0 nm at Lipo-DOX-Au and 94.1 ± 12.2 nm at Lipo-DOX-Au-RGD, and it was observed that doxorubicin was mounted inside the liposome up to 52%. After 6 hours of HIFU treatment, the viability of U87mg cells treated with Lipo-DOX-Au decreased by around 20% compared to Lipo-DOX, and Lipo-DOX-Au-RGD had a higher uptake rate than Lipo-DOX. In vivo study using PET images, it was confirmed that ⁶⁴Cu-Lipo-DOX-Au-RGD was taken up into the tumor immediately after injection and maintained for up to 4 hours. In this study, drugs released from liposomes-gold nanoparticles via ultrasound and RGD targeting were confirmed by non-invasive imaging. In cell-level experiments, HIFU treatment of gold nanoparticle-coupled liposomes significantly decreased tumor survival, while RGD-liposomes exhibited high tumor targeting and rapid release in vivo imaging. It is expected that the combination of these models with ultrasound is served as an effective drug delivery material with therapeutic outcomes.

• Korean Journal of Clinical Laboratory Science
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• v.56 no.3
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• pp.236-247
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• 2024

The human leukocyte antigen (HLA) system, which is part of the major histocompatibility complex (MHC) plays a vital role in immune responses by differentiating between itself and foreign cells and antigens. The significant diversity of alleles affects disease susceptibility and immune responses within different populations. Specifically, the HLA-A and HLA-DRB1 alleles are associated with various immune-related diseases, and understanding the frequency and haplotype associations of these alleles is vital for genetic and immunological research. To investigate the distribution of these characteristics in Koreans, we isolated peripheral blood mononuclear cells (PBMCs) from blood samples donated by volunteers at the Seoul Central Blood Bank and performed HLA typing on 790 samples. Our study found that the HLA-A and HLA-DRB1 alleles are widely distributed within the Korean population, with HLA-A^*24:02 (21.7%) and HLA-DRB1*09:01 (9.9%) being the most frequent. Significant haplotype associations between specific HLA-A and HLA-DRB1 alleles were identified using the Chi-square test, suggesting that certain genetic combinations may influence disease onset. This insight could contribute to the development of predictive and preventative strategies for various diseases. The unique genetic characteristics of the Korean population highlight the importance of studying the HLA allele and the haplotype distributions in this group as key indicators for understanding disease susceptibility.