• Journal of Soil and Groundwater Environment
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• v.26 no.1
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• pp.54-64
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• 2021

The chemical warfare agents (CWAs) have been developed for offensive or defensive purposes and used as chemical weapons in war and terrorism. The CWAs are exposed to the natural environment, transported through the water system and then eventually contaminate soil and groundwater. Therefore, effective decontamination technology to remediate CWAs are needed. The CWAs are extremely dangerous and prodution is strictly prohibited, therefore, it is difficult to use CWAs even in experimental purpose. In this study, 2,4-dichlorophenoxyacetic acid (2,4-D) was chosen as a model representative CWA because it is a simulant of anti-plant CWAs and one of the major component of agent orange. The optimum degradation conditions such as oxidant:activator ratio were determined. The effects of hydroxylamine and chelating agents such as citric acid (CA), oxalic acid (OA), malic acid (MA), and EDTA addition to increase Fe2+ activation were also investigated. Scavenger experiments using tert-butyl alcohol (TBA) and ethanol confirmed that although both sulfate (SO4•-) and hydroxyl radical (•OH) existed in Fe2+-persulfate system, sulfate radical was the predominant radical. To promote the Fe2+ activator effect, the effect of hydroxylamine as a reducing agent was investigated. In chelating agents assisted Fe2+-persulfate oxidation, the addition of 2 mM of CA and MA enhanced 2,4-D degradation. In contrast, EDTA and OA inhibited the 2,4-D removal due to steric hindrance effect.

• Restorative Dentistry and Endodontics
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• v.30 no.3
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• pp.178-183
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• 2005

This study was done to evaluate whether vital bleaching agents could influence on the translucency of the bovine enamel. The anterior bovine teeth that were extracted one day before and without any gross discoloration were obtained and then were preserved in physiologic saline. 6 mm cylindrical tooth specimens were fabricated with diamond puncher perpendicularly on labial surface of bovine tooth. After embedded in transparent acrylic resin with labial surface being exposed, they were cut to a thickness of 1.2 mm with low speed diamond saw (Isomat, Buehler Co., Lake Bluff, IL, USA). They were smoothly ground to 1 mm thickness of enamel with sandpaper. 24 specimens were randomly divided into 3 groups and control group respectively. Opalescence (10% carbamide peroxide, Ultradent, South Jordan, USA), Rembrandt (10% carbamide peroxide, DenMat, USA) and Opalescence F (15% carbamide peroxide with fluoride, Ultradent, USA) were applied on labial sides of the bovine enamel for 7 days (bleaching agents were reapplied every 24 hours) and the opposite surface was contacted to cotton that soaked in distilled water. The control group was soaked in distilled water. Three stimulus value X, Y and Z were evaluated with colorimeter (Color ' Color Differencerneter, Model TC-6FX, Tokyo Denshoku Co., Japan) on the labial surface of all specimen three times on white and black background plate before the bleaching agents were applied and on 3rd, 5th and 7th day after applied. The degree of translucency was normally assessed by measuring the inverse property, opacity (contrast ratio). 10% Opalescence, 15% Opalescence-F, and control group showed no significant variation in the translucency of bovine enamel, However Rembrandt decreased the translucency of it (p < 0.01).

• Journal of the Korean Society of Radiology
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• v.16 no.2
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• pp.103-113
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• 2022

In this paper, a combined ¹⁸F-FDG(fluorodeoxyglucose) and MNP(magnetic nanoparticles) contrast agent was synthesized using N-(p-maleimidophenyl) isocyanate as the crosslinker for use in simultaneous PET-MRI scans. PET-MRI images were acquired and evaluated before and after injection of the combined contrast imaging agent (¹⁸F-FDG labeled MNP) from a glioma stem cell mouse model. After setting the region of interest (ROI) on each acquired image, the area of the lesion was calculated by segmentation. As a result, the PET image was larger than the MRI. In particular, the simultaneous PET-MRI images showed accurate lesions along with the surrounding soft tissue. The mean and standard deviation values were higher in the MRI images alone than in the PET images or the simultaneous PET-MRI images, regardless of whether the contrast agent was injected. In addition, the simultaneous PET-MRI image values were higher than for the PET images. For PSNR experiments, the original image was PET Image using 18F-FDG, MRI using MNPs, and MRI without contrast medium, and the target image was simultaneous PET-MRI image using 18F-FDG labeled MNPs contrast medium. As a result, all of them appeared significantly, suggesting that the 18F-FDG labeled MNPs contrast medium is useful. Future research is needed to develop an agent that can simultaneously diagnose and treat through SPECT-MRI imaging research that can use various nuclides.

• Korean Journal of Radiology
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• v.22 no.9
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• pp.1547-1554
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• 2021

Objective: We aimed to investigate whether repeated intravascular administration of iodinated contrast media (ICM) or gadolinium-based contrast agents (GBCAs) within a short interval was associated with an increased risk of post-contrast acute kidney injury (PC-AKI). Materials and Methods: This retrospective study included 300 patients (mean age ± standard deviation, 68.5 ± 8.1 years; 131 male and 169 female) who had undergone at least one ICM-enhanced perfusion brain CT scan, had their baseline and follow-up serum creatinine levels available, and had not undergone additional contrast-enhanced examinations 72 hours before and after a time window of interest were included. The study population was divided into three groups: single-dose group and groups of patients who had received multiple contrast administrations in the time window of interest with the minimum contrast repeat interval either within 4 hours (0-4-hour group) or between 4 to 48 hours (4-48-hour group). Multivariable logistic regression analysis was conducted to evaluate the association between AKI and repeated ICM administrations. A similar supplementary analysis was performed including both ICM and GBCA. Results: When ICM was only considered ignoring GBCA, among 300 patients, 207 patients received a single dose of ICM, 58 had repeated doses within 4 hours (0-4-hour group), and 35 patients had repeated doses between 4 to 48 hours (4-48-hour group). Most patients (> 95%) had a baseline estimated glomerular filtration rate (eGFR) of ≥ 30 mL/min/1.73 m². AKI occurred in 7.2%, 13.8%, and 8.6% of patients in the single-dose, 0-4-hour, and 4-48-hour groups, respectively. In the 0-4-hour and 4-48-hour groups, additional exposure to ICM was not associated with AKI after adjusting for comorbidities and nephrotoxic drugs (all p values > 0.05). Conclusion: Repeated intravascular administrations of ICM within a short interval did not increase the risk of AKI in our study patients suspected of acute stroke with a baseline eGFR of ≥ 30 mL/min/1.73 m².

• Investigative Magnetic Resonance Imaging
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• v.11 no.2
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• pp.103-109
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• 2007

To develop an advanced non-linear curve fitting (NLCF) algorithm for performing dynamic susceptibility contrast study of the brain. The first pass effects give rise to spuriously high estimates of $K^{trans}$ for the voxels that represent the large vascular components. An explicit threshold value was used to reject voxels. The blood perfusion and volume estimation were accurately evaluated in the $T2^*$-weighted dynamic contrast enhanced (DCE)-MR images. From each of the recalculated parameters, a perfusion weighted image was outlined by using the modified non-linear curve fitting algorithm. The present study demonstrated an improvement of an estimation of the kinetic parameters from the DCE $T2^*$-weighted magnetic resonance imaging data with using contrast agents.

• Journal of the Korean Society of Radiology
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• v.15 no.1
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• pp.29-35
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• 2021

The purpose of this study was to investigate whether there is a difference in image quality before and after reducing the amount of contrast medium in cerebral hemorrhagic patients who periodically follow up CT, and after reducing the amount of contrast medium, the image before and after reduction was examined, and the image quality was assessed by setting ROI at each vessel location using MMWP program. First Rt. CCA, Lt.CCA. Rt.MCA, Lt.MCA and Basilar Artery each got an ROI. Second, the mean and standard deviation values for the ROI were obtained. Third, SNR and CNR were obtained through the average and standard deviation values obtained. T-test statistics show that the SNR and CNR values obtained show that the result values for SNR are Rt.CCA 0.765, Ltd.CCA 0.871, Rt.MCA 0.343 LT.MCA 0.235, Basilar alternative 0.916, result value for CNR Rt.CCA 0.088, Ltd.CCA 0.069, Rt.MCA 0.818, Let's...MCA 0.579 and Basilar Artery 0.878. The results obtained through the obtained SNR and CNR values showed no difference in the quality of the images before and after reducing contrast medium. Therefore, we hope that this study will be an indicator that reduces the burden on contrast agents on patients who do CT examinations periodically.

• Journal of the Korean Graphic Arts Communication Society
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• v.16 no.1
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• pp.55-67
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• 1998

The developing agent is the materials which first acts on silver grain and make it into metallic silver by reducing reaction. There are several types in developing agents, and according to Lumiere-Andresen principle, substitution product which has amino or hydroxyl group in benzen nucleus has a developing power, but all reducing substances are not in used .In the developing effect, not only the role of developing agent but also that of assistant materials are important. But In this work, we have studied effect, change by lith developing agent which require high contrast image. We made an developing experiment after having manufactured developing solution used hydroquinone and another developing agents like chlorohydroquinone, pyrocatcchol and pyrogallol as developing agent. And we added that did in addition of diethanolamine and ascorbic acid. and then we examined the possibility of use.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.7
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• pp.2807-2811
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• 2015

Scorpion venom peptides recently have attracted attention as alternative chemotherapeutic agents that may overcome the limitations of current drugs, providing specific cytotoxicity for cancer cells with an ability to bypass multidrug-resistance mechanisms, additive effects in combination therapy and safety. In the present study, BmKn-2 scorpion venom peptide and its derivatives were chosen for assessment of anticancer activities. BmKn-2 was identified as the most effective against human oral squamous cells carcinoma cell line (HSC-4) by screening assays with an $IC_{50}$ value of $29{\mu}g/ml$. The BmKn-2 peptide killed HSC-4 cells through induction of apoptosis, as confirmed by phase contrast microscopy and RT-PCR techniques. Typical morphological features of apoptosis including cell shrinkage and rounding characteristics were observed in treated HSC-4 cells. The results were further confirmed by increased expression of pro-apoptotic genes such as caspase-3, -7, and -9 but decrease mRNA level of anti-apoptotic BCL-2 in BmKn-2 treated cells, as determined by RT-PCR assay. In summary, the BmKn-2 scorpion venom peptide demonstrates specific membrane binding, growth inhibition and apoptogenic activity against human oral cancer cells.

• Journal of Korean Society on Water Environment
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• v.30 no.3
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• pp.304-310
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• 2014

The conventional methods for total residual chlorine such as iodometry and DPD colorimetric can cause secondary pollution due to additional agents, also have a wide error range. As for alternative, electrochemical method can measure TRC(Total residual chlorine), and is not required as additional agents, also very suitable for using the fields of ballast water because test time is relatively fast. Therefore, this study was investigated for changing charge by agitation, salt concentration, and temperature change. Charge showed differences based on changes of reduction peak with or without agitation. In contrast, TRC and charge were well correlated in constant agitation speed. As TRC and charge were analyzed with high correlations in constant salinity and temperature of ocean, thereby conductivity was firstly measured, and charge had high correlation for TRC in spite of changing salinity and temperature Pt electrode revealed high reliability ($r^2=0.960$) because it was rarely effected by TRC, On the other hand, Au electrode appeared inadequate ($r^2=0.767$) to use sensor in less than 1.0 ppm of TRC. For high accuracy and detection of TRC, Pt and Au electrodes for test time were, respectively, 14 and 22 seconds. As a result, Pt electrode was more valuable than Au electrode in terms of response time.

• Natural Product Sciences
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• v.2 no.1
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• pp.1-8
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• 1996

Flavonoids are widely distributed polyphenol compounds in plant kingdom and known to possess varieties of biological/pharmacological activities in vitro and in vivo. A search for antiinflammatory/immunoregulatory flavonoids as potential therapeutic agents has been continued, since serious side effects of currently used nonsteroidal and steroidal antiinflammatory drugs limit their long term uses for the inflammatory disorders. In this reserch, various flavonids were isolated and tested for their in vivo antiinflammatory activity and in vitro inhibitory activity of lymphocyte proliferation. Using a mouse ear edema assay, it was found that certain flavones/flavonols possess mild antiinflammatory activity and a C-2,3-double bond might be essential. Isoflavones were less active. These flavonoids inhibited in vitro lymphocyte proliferation, relatively specific for T-cell proliferation $(IC_{50}=1-10\;{\mu}M)$ and the inhibition was reversible. We have also tested several biflavonoid derivatives, since we recently found that biflavones were phospholipase $A_2$ inhibitors. It was demonstrated that biflavones such as ochnaflavone and ginkgetin inhibited lymphocyte proliferation induced by both concanavaline A and lipopolysaccharide. The inhibition was irreversible in contrast to that of flavones/flavonols. And antiinflammatory activity of biflavonoids are discussed.