• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.47 no.4
• /
• pp.361-368
• /
• 2021

The objective of this study was to establish technology for removing bacteria with human- and eco-friendly material. Staphylococcus aureus as an important component for balanced equilibrium among microbiomes, was cultured under various concentrations of phosphate. Experimental observation relating to physical properties was performed in an addition of phosphate buffer. Statistically minimum value of size and hardness using atomic force microscope was observed on the matured biofilm at 5 mM concentration of phosphate. As a result of absorbance for the biofilm tagged with dye, concentration of biofilm was reduced with phophate, too. To identify whether this reduction by phosphate at the 5 mM is caused by counter ion or not, sodium chloride was treated to the biofilm under the same condition. To elucidate components of the biofilm counting analysis of the biofilm using time-of-flight secondary ion mass spectrometry was employed. The secondary ions from the biofilm revealed that alteration of physical properties is consistent to the change of extracellular polymeric substrate (EPS) for the biofilm. Viscoelastic characterization of the biofilm using a controlled shear stress rheometer, where internal change of physical properties could be detected, exhibited a static viscosity and a reduction of elastic modulus at the 5 mM concentration of phosphate. Accordingly, bacteria at the 5 mM concentration of phosphate are attributed to removing the EPS through a reduction of elastic modulus for bacteria. We suggest that the reduction of concentration of biofilm induces dispersion which assists to easily spread its dormitory. In conclusion, it is elucidated that an addition of phosphate causes removal of EPS, and that causes a function of antibiotic.

• Economic and Environmental Geology
• /
• v.56 no.4
• /
• pp.421-433
• /
• 2023

The final disposal of spent nuclear fuel(SNF) from nuclear power plants takes place in a deep geological repository. The metal canister encasing the SNF is made of cast iron and copper, and is engineered to effectively isolate radioactive isotopes for a long period of time. The SNF is further shielded by a multi-barrier disposal system comprising both engineering and natural barriers. The deep disposal environment gradually changes to an anaerobic reducing environment. In this environment, sulfide is one of the most probable substances to induce corrosion of copper canister. Stress-corrosion cracking(SCC) triggered by sulfide can carry substantial implications for the integrity of the copper canister, potentially posing a significant threat to the long-term safety of the deep disposal repository. Sulfate can exist in various forms within the deep disposal environment or be introduced from the geosphere. Sulfate has the potential to be transformed into sulfide by sulfate-reducing bacteria(SRB), and this converted sulfide can contribute to the corrosion of the copper canister. Bentonite, which is considered as a potential material for buffering and backfilling, contains oxidized sulfate minerals such as gypsum(CaSO4). If there is sufficient space for microorganisms to thrive in the deep disposal environment and if electron donors such as organic carbon are adequately supplied, sulfate can be converted to sulfide through microbial activity. However, the majority of the sulfides generated in the deep disposal system or introduced from the geosphere will be intercepted by the buffer, with only a small amount reaching the metal canister. Pyrite, one of the potential sulfide minerals present in the deep disposal environment, can generate sulfates during the dissolution process, thereby contributing to the corrosion of the copper canister. However, the quantity of oxidation byproducts from pyrite is anticipated to be minimal due to its extremely low solubility. Moreover, the migration of these oxidized byproducts to the metal canister will be restricted by the low hydraulic conductivity of saturated bentonite. We have comprehensively analyzed and summarized key research cases related to the presence of sulfates, reduction processes, and the formation and behavior characteristics of sulfides and pyrite in the deep disposal environment. Our objective was to gain an understanding of the impact of sulfates and sulfides on the long-term safety of high-level radioactive waste disposal repository.

• The Korean Journal of Nuclear Medicine Technology
• /
• v.14 no.2
• /
• pp.33-37
• /
• 2010

Purpose: In the early stage of using PET/CT, it was used to damper revision but recently shows that CT with MDCT is commonly used and works well for an anatomical diagnosis. This hospital makes the accuracy and convenience more higher in the diagnosis and evaluate of coronary heart disease through concurrently running myocardial perfusion SPECT examination, myocardial PET examination with FDG, and CT coronary artery CT angiography(coronary CTA) used PET/CT with 64-slice. This report shows protocol and image based on results from about 400 coronary heart disease examinations since having 64 channels PET/CT in July 2007. Materials and Methods: An Equipment for this examination is 64-slice CT and Discovery VCT (DVCT) that is consisted of PET with BGO ($Bi_4Ge_3O_{12}$) scintillation crystal by GE health care. First myocardial perfusion SPECT with pharmacologic stress test to reduce waiting time of a patient and get a quick diagnosis and evaluation, and right after it, myocardial FDG PET examination and coronary CTA run without a break. One-stop evaluation protocol of ischemic heart disease is as follows. 1)Myocardial perfusion SPECT with pharmacologic stress: A patient is injected with $^{99m}Tc$-MIBI 10 mCi and does not have any fatty food for myocardial PET examination and drink natural water with ursodeoxcholic acid 100 mg and we get SPECT image in an hour. 2)Myocardial FDG PET: To reduce blood fatty content and to increase uptake of FDG, we used creative oral glucose load using insulin and Acipimox to according to blood acid content. A patient is injected with $^{18}F$-FDG 5 mCi for reduction of his radiation exposure and we get a gated image an hour later and get delay image when we need. 3) Coronary CTA: The most important point is to control heart rate and to get cooperation of patient's breath. In order to reduce a heart rate of him or her below 65 beats, let him or her take beta blocker 50 mg ~ 200 mg after a consultation with a doctor about it and have breath-practices then have the examination. Right before the examination, we spray isosorbide dinitrate 3 to 5 times to lower tension of bessel wall and to extension a blood wall of a patient. It makes to get better the shape of an anatomy. At filming, a patient is injected CT contrast with high pressure and have enough practices before the examination in order to have no problem. For reduction of his radiation exposure, we have to do ECG-triggered X-ray tube modulation exposure. Results: We evaluate coronary artery stenosis through coronary CTA and study correlation (culprit vessel check) of a decline between stenosis and perfusion from the myocardial perfusion SPECT with pharmacologic stress, coronary CTA, and can check viability of infarction or hibernating myocardium by FDG PET. Conclusion: The examination makes us to set up a direction of remedy (drug treatment, PCI, CABG) because we can estimate of effect from remedy, lesion site and severity. In addition, we have an advantage that it takes just 3 hours and one-stop in that all of process of examinations run in succession and at the same time. Therefore it shows that the method is useful in one stop evaluation of ischemic heart disease.

• MISULJARYO - National Museum of Korea Art Journal
• /
• v.104
• /
• pp.70-100
• /
• 2023

The celadon made in the Goryeo era, a time when Buddhism was flourishing in Korea, naturally contains many elements of Buddhist culture. Among them, inlaid celadon with Sanskrit inscriptions bears a close relationship with esoteric Buddhism. However, the research on deciphering the Sanskrit inscriptions has made little progress due to the small number of extant examples. However, the four recent excavations at the No. 23 kiln site in Sadang-ri, Gangjin have yielded new materials that allow the existing materials to be categorized into several types. The results obtained through the reading and interpretation of the inscriptions are as follows: First, the Sanskrit characters inlaid on the celadon were parts of mantras. Inscriptions where only one character is apparent cannot be deciphered, but scholars have revealed that others are written in the manner of a wheel mantra represent the "Mantra for Purifying the Dharma-Realm," "Six-Syllable Mantra of the Vidyaraja," "Sweet Dew Mantra," "Jewel Pavilion Mantra," "Mantra of the Savior Bodhisattva," "Dharani of the Mind of the Budha of Infinite Life," and "Mantra for Extinguishing Evil Rebirth." Each mantra was written in Siddham script. Second, they are believed to have been produced during the thirteenth and fourteenth centuries based on the arrangement of the inscriptions and the way the "Sweet Dew Mantra" is included in the "40 Hands Mantra." In particular, the celadon pieces with a mantra inlaid in a concentric manner are dated to the late thirteenth and early fourteenth centuries based on their production characteristics. Third, the interpretation of the inlaid mantras suggests that they all refer to the "Shattering Hell" and "Rebirth in the Pure Land." Based on this, it can be concluded that some of these inlaid celadon wares with mantras may have been used in Buddhist rituals for the dead, such as the ritual for feeding hungry ghosts (施餓鬼會). Also, because the Sadang-ri No. 23 kiln site and the "ga" area of the site are believed to have produced royal celadon, it is likely that these rituals were performed at the royal court or a temple under its influence. Fourth, this inlaid Goryeo celadon with Sanskrit mantras was not a direct influence of the ceramics of Yuan China. It emerged by adopting Yuan Chinese Buddhist culture, which was influenced by Tibetan Buddhism, into Goryeo Korea's existing esoteric practices. Fifth, the celadon wares inlaid with a Sanskrit mantra reveal a facet of the personal esoteric rituals that prevailed in late Goryeo society. Changes in esotericism triggered by the desire for relief from anxieties can be exemplified in epitaph tablets and coffins that express a shared desire for escaping hell and being born again in paradise. Sixth, the inlaid celadon with Sanskrit mantras shares some common features with other crafts. The similarities include the use of Siddham Sanskrit, the focus on Six-Syllable Mantra of the Vidyaraja, the correspondence with the contents of the mantras found on Buddhist bells, wooden coffins, and memorial tablets, and their arraignment in a similar manner with rooftiles. The major difference between them is that the Mantra for Extinguishing Evil Rebirth and the Sweet Dew Manta have not yet been found on other craftworks. I believe that the inscriptions of Sanskrit mantras are found mainly on inlaid celadon vessels due to their relatively low production cost and efficiency.