• Journal of Life Science
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• v.29 no.2
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• pp.265-271
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• 2019

In general, specific gravity (SG) and urinary creatinine (CR) have been used to adjust urinary cadmium (Cd) concentrations. However, the validity of correction methods has been controversial. We compared the two adjustments to evaluate associations between urinary Cd and various renal damage markers and to evaluate the relationship between urinary Cd concentration and renal disease markers, such as estimated glomerular filtration rate (eGFR), in a relatively large general population sample. Among the 1,086 volunteers who were enrolled in this study, 862 healthy volunteers who did not have kidney disease were included in the final analysis. Urinary Cd, malondialdehyde (MDA), and N-acetyl-${\beta}$-D-glucosaminidase (NAG) concentrations were measured, the creatinine-based eGFR was calculated, and the relationships between these markers were subsequently analyzed. This study showed the use of urinary Cd concentration adjusted with SG rather than with urinary creatinine may be appropriate in studies evaluating renal function based on Cd exposure. Urinary Cd concentration adjusted with SG had a positive correlation with urinary MDA levels and a negative correlation with eGFR. This relationship was relatively stronger in women than in men. This study showed that urinary Cd level was associated with decreased eGFR in the general population, and oxidative stress was likely to act as an intermediator in this process. These results suggest that eGFR can be a very good indicator of kidney damage caused by Cd exposure in the general population.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.2
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• pp.257-262
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• 2002

Effects of dietary fatty acids and vitamin E on antioxidant system were studied in rat liver and serum. Sources of dietary fat (10 wt%) were safflower oil (SO) poor in $\omega$3 fatty acid and mixed oil (MO) with computer-adjusted fatty acid ratios (AA/DHA=1.4, $\omega$6/$\omega$3=6.3, P/M/S=1.0/l.5/1) with (ME) and without (MO) vitamin E (500 mg/kg diet). Rats were fed the three kinds of diet from 3~4 wks prior to the conception. At the age of 3 and 9 wks of the second generation rat, antioxidant vitamins and glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) activities were measured in the liver and serum. The concentrations of $\beta$-carotene were lower in ME than in MO and SO in the liver at the age of 3 wks. It seemed that vitamin E has an inhibitory action on the uptake of $\beta$-carotene or acts as a preferred antioxidant to $\beta$-carotene. The concentrations of lycopene were lower in SO than in MO in the liver at the age of 3 wks. The concentrations of cryptoxanthin showed no significant changes within groups. The activities of GSH-Px tended to increase in ME compared to MO and the ratios of SOD/GSH-Px tended to decrease in ME compared to MO in the liver at the age of 3 weeks. The activities of antioxidant enzyme at the age of 3 weeks and 9 weeks were similar. This suggested that the activity level of antioxidant enzymes reached to the adult level at the age of 3 weeks which is the end point of lactation period.

• Radiation Oncology Journal
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• v.19 no.1
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• pp.16-20
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• 2001

Purpose : To evaluate the effectiveness and tolerance of the postoperative radiation therapy for patients with Stage III thymoma and to define the optimal radiotherapeutic regimen Materials and Methods : We retrospectively analyzed the records of 24 patients with Stage III thymoma who were referred for postoperative radiation therapy in our institution from June, 1987 to May, 1999. Surgical therapy consisted of total resection in one patient, subtotal resection in seventeen, and biopsy alone in six patients. Age of the patients was ranged from 20 to 62 years with mean age of 47 years. Male to female ratio was 14 to 10. Radiation therapy was delivered with linear accelerator producing either 6 MeV or 10 MeV photons. The irradiated volume included anterior mediastinum and known residual disease. The supraclavicular fossae were not irradiated. The delivered total dose was ranged from 30 to 56 Gy. One patient received 30 Gy and eighteen patients received minimum of 50 Gy. Follow up period was ranged from 12 months to 8 years with median follow up of 40 months. Results : The overall local control rate for entire group of patients was $67\%$ at 5 years. The cumulative local failure rates at one, three and five year were $18\%,\;28\%\;and\;33\%$, respectively. In patients treated with subtotal resection and biopsy alone, local control rate was $76\%\;and\;33\%$, respectively. The actuarial observed survival rate at 5 years was $57\%$, and actuarial adjusted survival at 5 years was $72\%$. The difference between 5 year survival rates for patients treated with subtotal resection and biopsy alone was not statistically significant $(62\%\;vs\;30\%)$. Conclusion : We might conclude that postoperative radiation therapy was safe and effective treatment for patients with Stage III thymoma. Postoperative radiation therapy is recommended in cases where tumor margin is close or incomplete resection is accomplished.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.15-15
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• 2011

As you know, boron compounds, borax ($Na_2B_4O_5(OH)_4{\cdot}8H_2O$) etc. were known thousands of years ago. As for natural boron, it has two naturally occurring and stable isotopes, boron 11 ($^{11}B$) and boron 10 ($^{10}B$). The neutron absorption $^{10}B$ is included about 19~20% with 80~81% $^{11}B$. Boron is similar to carbon in its capability to form stable covalently bonded molecular networks. The mass difference results in a wide range of ${\beta}$ values between the $^{11}B$ and $^{10}B$. The $^{10}B$ isotope, stable with 5 neutrons is excellent at capturing thermal neutrons. For example, it is possible to decrease a thermal neutron required for the nuclear reaction of uranium 235 ($^{235}U$). If $^{10}B$ absorbs a neutron ($^1n$), it will change to $^7Li+^1{\alpha}$ (${\alpha}$ ray, like $^4He$) with prompt ${\gamma}$ ray from $^{11}B$ $^{11}B$ (equation 1). $$^{10}B+^1n\;{\rightarrow}\;^{11}B\;{\rightarrow}\; prompt \;{\gamma}\;ray (478 keV), \;^7Li+4{\alpha}\;(4He)\;\;\;\;{\cdots}\; (1)$$ If about 1% boron is added to stainless steel, it is known that a neutron shielding effect will be 3 times the boron free steel. Enriched boron or $^{10}B$ is used in both radiation shielding and in boron neutron capture therapy. Then, $^{10}B$ is used for reactivity control and in emergency shutdown systems in nuclear reactors. Furthermore, boron carbide, $B_4C$, is used as the charge of a nuclear fission reaction control rod material and neutron cover material for nuclear reactors. The $B_4C$ powder of natural B composition is used as a charge of a control material of a boiling water reactor (BWR) which occupies commercial power reactors in nuclear power generation. The $B_4C$ sintered body which adjusted $^{10}B$ concentration is used as a charge of a control material of the fast breeder reactor (FBR) currently developed aiming at establishment of a nuclear fuel cycle. In this study for new boron compound, silicon boride ceramics for capturing thermal neutrons, preparation and characterization of both silicon tetraboride ($SiB_4$) and silicon hexaboride ($SiB_6$) and ceramics produced by sintering were investigated in order to determine the suitability of this material for nuclear power generation. The relative density increased with increasing sintering temperature. With a sintering temperature of 1,923 K, a sintered body having a relative density of more than 99% was obtained. The Vickers hardness increased with increasing sintering temperature. The best result was a Vickers hardness of 28 GPa for the $SiB_6$ sintered at 1,923K for 1 h. The high temperature Vickers hardness of the $SiB_6$ sintered body changed from 28 to 12 GPa in the temperature range of room temperature to 1,273 K. The thermal conductivity of the SiB6 sintered body changed from 9.1 to 2.4 W/mK in the range of room temperature to 1,273 K.

• Tuberculosis and Respiratory Diseases
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• v.80 no.3
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• pp.296-303
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• 2017

Background: Acute respiratory distress syndrome (ARDS) is related to high mortality and morbidity. There are no proven therapeutic measures however, to improve the clinical course of ARDS, except using low tidal volume ventilation. Metformin is known to have pleiotropic effects including anti-inflammatory activity. We hypothesized that pre-admission metformin might alter the progress of ARDS among intensive care unit (ICU) patients with diabetes mellitus (DM). Methods: We performed a retrospective cohort study from January 1, 2005, to April 30, 2005 of patients who were admitted to the medical ICU at Seoul National University Hospital because of ARDS, and reviewed ARDS patients with DM. Metformin use was defined as prescribed within 3-month pre-admission. Results: Of 558 patients diagnosed with ARDS, 128 (23.3%) patients had diabetes and 33 patients were treated with metformin monotherapy or in combination with other antidiabetic medications. Demographic characteristics, cause of ARDS, and comorbid conditions (except chronic kidney disease) were not different between metformin users and nonusers. Several severity indexes of ARDS were similar in both groups. The 30-day mortality was 42.42% in metformin users and 55.32% in metformin nonusers. On multivariable regression analysis, use of metformin was not significantly related to a reduced 30-day mortality (adjusted ${\beta}-coefficient$, -0.19; 95% confidence interval, -1.76 to 1.39; p=0.816). Propensity score-matched analyses showed similar results. Conclusion: Pre-admission metformin use was not associated with reduced 30-day mortality among ARDS patients with DM in our medical ICU.

• The Korean Journal of Nuclear Medicine
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• v.31 no.4
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• pp.427-432
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• 1997

Re-188 is useful candidate for therapeutic radionuclide because it has a physical half life of 17 hours, contains beta emissions suitable for therapy(maximum energy 2.12MeV) and emits a gamma ray that is suitable for quantitative diagnostic scanning(155keV). To use Re-188 as a radionuclide compound of angioplasty balloon radiotherapy, we investigated the labelling method and biodistribution of Re-188-DTPA We postulated that labeled Re-188-DTPA is preferable because it would be excreted via urinary system more easily than other compounds. To label Re-188 with DTPA, 1ml of 222MBq(6mCi) of Re-188 was added to DTPA solution(DTPA 20mg, $SnCl_2{\cdot}2H_2O$ 10mg, pH 3.5) and boiled at $100^{\circ}C$ for 120min in water bath. pH was adjusted to 5 with 2.3% sodium acetate. Labeling efficiency was measured using TLC-SG(acetone, saline). We evaluated biodistribution of Re-188-DTPA in sacrificed mice at 10 and 60 minutes after injection. We acquired images of kidneys, and drew time-activity curves in normal dogs and rats and calculated Tmax and Tl/2 in rats. The labelling efficiency was 95.7% on average. Labelling of Re-188-DTPA was.stable(90% after 5hours) in vitro at room temperature. According to time-activity curves of dogs and rats, it took 15 to 20 minutes after injection for Re-188-DTPA to be washed out through kidneys. In conclusion, Re-188-DTPA was successfully labeled, Re-188-DTPA was stable in vitro and was excreted early via kidneys in animals. We could recommend Re-188-DTPA as radionuclide of potential use in angioplasty balloon radiotherapy.

• Korean Journal of Optics and Photonics
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• v.29 no.6
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• pp.241-246
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• 2018

In this paper, a low-cost optical temperature sensor is implemented, using a fiber Bragg grating (FBG) as the temperature probe and a low-cost VCSEL with temperature-dependent output wavelength as the light source. To analyze the wavelength of the reflected light from the FBG, an interrogation was applied using a method of referring to the internal temperature according to the output wavelength of the VCSEL. When the temperature of the VCSEL was adjusted from 14 to $52.2^{\circ}C$, the output wavelength varied from 1519.90 to 1524.25 nm. The degree of wavelength tuning according to temperature was $0.114nm/^{\circ}C$. The variable wavelength repeatability error according to temperature was ${\pm}0.003nm$, and the temperature measurement error was ${\pm}0.18^{\circ}C$. As a result of measuring the temperatures from 22.3 to $194.2^{\circ}C$, the value of the internal temperature change of the light source according to the applied temperature ${\Delta}T$ was $0.146^{\circ}C/{\Delta}T$, the change in reflected wavelength of the temperature probe according to applied temperature ${\Delta}T$ was measured at $16.64pm/^{\circ}C$. and the temperature measurement error of the sensor was ${\pm}1^{\circ}C$.

• Analytical Science and Technology
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• v.22 no.4
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• pp.326-335
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• 2009

A specific analytical method able to identify and quantify traces of six glucocorticoids residues in eggs were developed. The extraction and clean-up parameters for simultaneous analysis were evaluated and HPLC and spectrometric conditions were also established. For determination of glucocorticoids, 5 g of egg was transferred into a test tube, adjusted pH 5.2 with acetate buffer and was $\beta$-glucuronidase/arylsulfatase from Helix pomatia added. The mixture was centrifuged and supernatant was extracted twice with 20 mL n-hexane. The extraction was performed with HLB cartridge using methanol, followed by clean-up with silica cartridge using methanol/ethyl acetate (4/6, v/v). The analytes were determined by HPLC/ESI-MS/MS operating in the negative ion mode. Validation studies with fortified egg samples for established method were performed. The result of method validation gave good efficiency, linearity, accuracy and precision. The correlation coefficients ($r^2$) of the calibration curves appeared to be higher than 0.99 in egg, indicating excellent linearity. LOD was ranged 0.09 to $0.17{\mu}g/kg$, and recoveries for most compounds were in the range of 55.7-69.8%. This method can be used to determine ${\mu}g/kg$ levels of glucocorticoids in eggs.

• Analytical Science and Technology
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• v.23 no.6
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• pp.531-536
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• 2010

A quantitative analytical method has been established for the measurement of inosine 5'-monophosphate dehydrogenase (IMPDH) activity in human peripheral blood mononuclear cells (PBMCs) by ion-pair reversed-phase high performance liquid chromatography equipped with ultraviolet detection (HPLC/UV). IMPDH is a ${\beta}$-nicotinamide adenine dinucleotide hydrate (NAD+)-dependent dehydrogenase in which the enzyme converts inosine 5'-monophosphate (IMP) into xanthosine 5'-monophosphate (XMP). Its activity was measured by quantifying a HPLC chromatogram corresponding to XMP produced during the incubation of lysed PBMCs with IMP as a substrate and $NAD^+$ as a coenzyme. XMP produced was detected at a wavelength of 260 nm. The mobile phase was composed of a mixture of 37 mM potassium dihydrogen phosphate containing 7 mM tetra-n-butylammonium hydrogen sulfate adjusted to pH 5.5 and methanol (85:15, v/v) with a flow rate of 1 mL/min. The calibration curve was linear ($r^2$=0.999999) in the range of $0.2-50.0\;{\mu}M$ and the limit of quantification (LOQ) was $0.2\;{\mu}M$. The intra- and inter-day precisions were between 0.88-1.47% and 0.85-5.24%, respectively. The intra- and inter-day accuracies were between 98.74-99.99% and 99.95-101.65%, respectively. IMPDH activity in 11 Korean healthy volunteers ranged from 18.29 to 36.60 nmol/h/mg protein (mean = $27.70{\pm}6.28\;nmol/h/mg$ protein).

• The Korean Journal of Nuclear Medicine
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• v.39 no.1
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• pp.44-48
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• 2005

Purpose: Ethylenediamine-tetramethylenephosphonic acid (EDTMP) has widely used chelator for the labeling of bone seeking radiopharmaceuticals complexed with radiometals. $^{153}Sm$ can be produced by the HANARO reactor at the Korea Atomic Energy Research Institute, Taejon, Korea. $^{153}Sm$ has favourable radiation characteristics $T1/2=46.7\;h,\;{\beta}_{max}=0.81\;MeV\;(20%),\;0.71\;MeV\;(49%),\;0.64\;MeV\;(30%)\;and\;{\gamma}=103\;keV\;(30%)$ emission which is suitable for imaging purposes during therapy. We investigated the labeling condition of $^{153}Sm$-EDTMP and imaging of $^{153}Sm$-EDTMP in normal rats. Materials and methods: EDTMP 20 mg was solved in 0.1 mL 2 M NaOH. $^{153}SmCl^3$ was added to EDTMP solution and pH of the reaction mixtures was adjusted to 3 and 12, respectively. Radiochemical purity was determined with paper chromatography. After 30 min. reaction, reaction mixtures were neutralized to pH 7.4, and the stability was estimated upto 120 hrs. Imaging studies of each reaction were perfomed in normal rats (37 MBq/0.1 mL). Results: The labeling yield of $^{153}Sm$-EDTMP was 99%. The stability of pH 8 reaction at 60, 96 and 120 hr was 99%, 95%, 89% and that of pH 12 at 36, 60, 96 and 120 hr was 99%, 95%, 88%, 66%, respectively. The $^{153}Sm$-EDTMP showed constantly higher bone uptake from 2 to 48 hr after injection. Conclusion: $^{153}Sm$-EDTMP, labeled at pH 8 reaction condition, has been stably maintained. Image of $^{153}Sm$-EDTMP at 2, 24, 48 hr after injection, demonstrate that $^{153}Sm$-EDTMP is a good bone seeking radiopharmaceuticals.