• Journal of Korean Ophthalmic Optics Society
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• v.16 no.3
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• pp.327-331
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• 2011

Purpose: The purpose of this study was an accurate grasp of the astigmatic change due to eyes accommodation on near vision and suggested problems occurring accommodative astigmatism using near glasses. Methods: 154 subjects(308eyes) from 20 to 40 years selected for this study who had many opportunity of near vision. First, far vision corrective refraction measured using the phoropter, and then both eyes opened simultaneously for maintaining the function of binocular put away dot chart 40 cm. One eye was fogging and the other eye measured near vision astigmatism axis and degrees astigmatism using cross cylinder, and then compared with far astigmatism. Results: Increased degree of astigmatism persons on near vision more than decreased or did not changed degree of astigmatism persons, which could affect visual acuity more than 0.75 diopters in 30 eyes with an increase of 9.7% of total subjects. Direct astigmatism and oblique astigmatism were increased on near vision. Astigmatic axes were rotated base in direction on both eyes and 66.9% of subjects were more than ${\pm}$5$^{\circ}$ rotation. Due to the rotation axis of astigmatism, residual astigmatism is expected to occur and expect to adversely affect the eyes. Conclusions: Long-term using the glasses without correction of increased astigmatic and rotated axis on near vision should occur new residual astigmatism and increase the asthenopia also. Considered to be taken astigmatic change on near vision during near refraction examination.

• Journal of Sericultural and Entomological Science
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• v.50 no.2
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• pp.116-121
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• 2012

Cordyceps and its allies fungi has been described as a secret medicine that gives eternal youth and a long life. Some species of Cordyceps are sources of biochemicals, such ascordycepin, with interesting biological and pharmacological properties. Hence, it has been studied to uncover its pharmacological effect. We attempted to study the formation of fruiting bodies and to develop means of mass production Korean isolate of Paecilomyces tenuipes has been inoculated into silkworms, where it reproduced using culture container, mini-kit successfully. Culture container, mini-kit is composed of a cylinder-shaped body and lid. The container is made of translucent polyethylene terephthalate. The size of the container is $82{\times}75mm$, reduced by 10 times as compared with the conventional culture kit. The mini kit has many advantages - high culture amount, ability of maintaining optimal humidity, parasite-free cultivation and high-end appearance. With the kit, the optimal cultivation condition is under $22^{\circ}C$, culture period of 53 days. And synnemata of P. tenuipes could be kept fresh for 14 days at the temperature of under $10^{\circ}C$. Therefore, the Min-kit can be used in both ways as a culture container and a packing kit for end-user customers.

• Journal of the Korean Institute of Gas
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• v.25 no.4
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• pp.49-56
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• 2021

Liquefied Petroleum Gas is divided into liquefied gases containing propane (C₃H₈) and butane (C₄H₁₀). The quality of LPG varies greatly depending on the composition of the mixture, so it is important to measure the composition accurately. It is difficult to determine the composition of the mixture because liquid and gas coexist at room temperature. Therefore, the uncertainty in determining the concentration of hydrocarbons by component is high, and there are many problems that differ from the actual content standard. Therefore, it is necessary to develop a mixed liquid propane standard gas for the composition and accurate concentration of hydrocarbon substances. Mixed liquid propane standard gas is manufactured into bellows-type constant-pressure cylinders by ISO-6142 (2015). The homogeneity of the four standard gases manufactured was confirmed to be GC-FID. The manufacturer's uncertainty of expansion was 0.01 % to 0.30 % and homogeneity was 0.03 % to 0.25 %. In this mixed liquid propane standard gas, the relative expansion uncertainty of weight method, manufacturing consistency, cylinder adsorption and long-term stability was developed within 0.26 %-1.3 9% (95% of confidence level, k=2).

• Advances in nano research
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• v.13 no.6
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• pp.575-585
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• 2022

Due to its biofilm formation and colonization of the osteocyte-lacuno canalicular network (OLCN), Staphylococcus aureus (S.aureus) implant-associated bone infection (SIABI) is difficult to cure thoroughly, and may occur recurrently subsequently after a long period dormant. It is essential to explore an alternative therapeutic strategy that can eradicate the pathogens in the infected foci. To address this, the polymethylmethacrylate (PMMA) bone cement and Fe3O4 nanoparticles compound cylinder were developed as implants based on their size and mechanical properties for the alternative magnetic field (AMF) induced thermal ablation, The PMMA mixed with optimized 2% Fe₃O₄ nanoparticles showed an excellent antibacterial efficacy in vitro. It was evaluated by the CFU, CT scan and histopathological staining on a rabbit 1-stage transtibial screw model. The results showed that on week 7, the CFU of infected soft tissue and implants, and the white blood cells (WBCs) of the PMMA+2% Fe₃O₄+AMF group decreased significantly from their controls (p<0.05). PMMA+2% Fe₃O₄+AMF group did not observe bone resorption, periosteal reaction, and infectious reactive bone formation by CT images. Further histopathological H&E and Gram Staining confirmed there was no obvious inflammatory cell infiltration, neither pathogens residue nor noticeably burn damage around the infected screw channel in the PMMA+2% Fe₃O₄+AMF group. Further investigation of nanoparticle distributions in bone marrow medullary and vital organs of heart, liver, spleen, lung, and kidney. There were no significantly extra Fe₃O₄ nanoparticles were observed in the medullary cavity and all vital organs either. In the current study, PMMA+2% Fe₃O₄+AMF shows promising therapeutic potential for SIABI by providing excellent mechanical support, and promising efficacy of eradicating the residual pathogenic bacteria in bone infected lesions.

• The Korean Journal of Nuclear Medicine Technology
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• v.14 no.2
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• pp.21-25
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• 2010

Purpose: For better PET imaging with accuracy the transmission scanning is inevitably required for attenuation correction. The attenuation is affected by condition of acquisition and patient position, consequently quantitative accuracy may be decreased in emission scan imaging. In this paper, the present study aims at providing the measurement for attenuation varying with the positions of the patient's arm in whole body PET/CT, further performing the comparative analysis over its SUV changes. Materials and Methods: NEMA 1994 PET phantom was filled with $^{18}F$-FDG and the concentration ratio of insert cylinder and background water fit to 4:1. Phantom images were acquired through emission scanning for 4min after conducting transmission scanning by using CT. In an attempt to acquire image at the state that the arm of the patient was positioned at the lower of ahead, image was acquired in away that two pieces of Teflon inserts were used additionally by fixing phantoms at both sides of phantom. The acquired imaged at a were reconstructed by applying the iterative reconstruction method (iteration: 2, subset: 28) as well as attenuation correction using the CT, and then VOI was drawn on each image plane so as to measure CT number and SUV and comparatively analyze axial uniformity (A.U=Standard deviation/Average SUV) of PET images. Results: It was found from the above phantom test that, when comparing two cases of whether Teflon insert was fixed or removed, the CT number of cylinder increased from -5.76 HU to 0 HU, while SUV decreased from 24.64 to 24.29 and A.U from 0.064 to 0.052. And the CT number of background water was identified to increase from -6.14 HU to -0.43 HU, whereas SUV decreased from 6.3 to 5.6 and A.U also decreased from 0.12 to 0.10. In addition, as for the patient image, CT number was verified to increase from 53.09 HU to 58.31 HU and SUV decreased from 24.96 to 21.81 when the patient's arm was positioned over the head rather than when it was lowered. Conclusion: When arms up protocol was applied, the SUV of phantom and patient image was decreased by 1.4% and 9.2% respectively. With the present study it was concluded that in case of PET/CT scanning against the whole body of a patient the position of patient's arm was not so much significant. Especially, the scanning under the condition that the arm is raised over to the head gives rise to more probability that the patient is likely to move due to long scanning time that causes the increase of uptake of $^{18}F$-FDG of brown fat at the shoulder part together with increased pain imposing to the shoulder and discomfort to a patient. As regarding consideration all of such factors, it could be rationally drawn that PET/CT scanning could be made with the arm of the subject lowered.

• The Korean Journal of Nuclear Medicine
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• v.29 no.4
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• pp.533-540
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• 1995

Attenuation correction is important in producing quantitative positron emission tomography (PET) images. Conventionally, photon attenuation effects are corrected using transmission measurements performed before tracer administration. The pre-injection transmission measurement approach may require a time delay between transmission and emission scans for the tracer studies requiring a long uptake period, about 45 minutes for F-18 deoxyglucose study. The time delay will limit patient throughput and increase the likelihood of patient motion. A technique lot performing simultaneous transmission and emission scans (T+E method) after the tracer injection has been validated. The T+E method substracts the emission counts contaminating the transmission measurements to produce accurate attenuation correction coefficients. This method has been evaluated in experiments using a cylindrical phantom filled with background water (5750 cc) containing $0.4{\mu}Ci/cc$ of F-18 fluoride ion and one insert cylinder (276 cc) containing $4.3{\mu}Ci/cc$. GE $Advance^{TM}$ PET scanner and Ge-68 rotating pin sources for transmission scanning were used for this investigation. Post-injection transmission scan and emission scan were peformed alternatively over time. The error in emission images corrected using post-infection transmission scan to emission images corrected transmission scan was 2.6% at the concentration of $1.0{\mu}Ci/cc$. No obvious differences in image quality and noise were apparent between the two images. The attenuation correction can be accomplished with post-injection transmission measurement using rotating pin sources and this method can significantly shorten the time between transmission and omission scans and thereby reduce the likelihood of patient motion and increase scanning throughput in PET.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.18 no.1
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• pp.40-46
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• 2013

The isotope ratios of $^{13}C/^{12}C$ and $^{18}O/^{16}O$ for a sample in a mass spectrometer are measured relative to those of a pure $CO_2$ reference gas (i.e., laboratory working standard). Thus, the calibration of a laboratory working standard gas to the international isotope scales (Pee Dee Belemnite (PDB) for ${\delta}^{13}C$ and Vienna Standard Mean Ocean Water (V-SMOW) for ${\delta}^{18}O$) is essential for comparisons between data sets obtained by other groups on other mass spectrometers. However, one often finds difficulties in getting well-calibrated standard gases, because of their production time and high price. Additional difficulty is that fractionation processes can occur inside the gas cylinder most likely due to pressure drop in long-term use. Therefore, studies on laboratory production of pure $CO_2$ isotope standard gas from stable solid calcium carbonate standard materials, have been performed. For this study, we propose a method to extract pure $CO_2$ gas without isotope fractionation from a solid calcium carbonate material. The method is similar to that suggested by Coplen et al., (1983), but is better optimized particularly to make a large amount of pure $CO_2$ gas from calcium carbonate material. The $CaCO_3$ releases $CO_2$ in reaction with 100% pure phosphoric acid at $25^{\circ}C$ in a custom designed, evacuated reaction vessel. Here we introduce optimal procedure, reaction conditions, and samples/reactants size for calcium carbonate-phosphoric acid reaction and also provide the details for extracting, purifying and collecting $CO_2$ gas out of the reaction vessel. The measurements for ${\delta}^{18}O$ and ${\delta}^{13}C$ of $CO_2$ were performed at Seoul National University using a stable isotope ratio mass spectrometer (VG Isotech, SIRA Series II) operated in dual-inlet mode. The entire analysis precisions for ${\delta}^{18}O$ and ${\delta}^{13}C$ were evaluated based on the standard deviations of multiple measurements on 15 separate samples of purified $CO_2$. The pure $CO_2$ samples were taken from 100-mg aliquots of a solid calcium carbonate (Solenhofen-ori $CaCO_3$) during 8-day experimental period. The multiple measurements yielded the $1{\sigma}$ precisions of ${\pm}0.01$‰ for ${\delta}^{13}C$ and ${\pm}0.05$‰ for ${\delta}^{18}O$, comparable to the internal instrumental precisions of SIRA. Therefore, we conclude the method proposed in this study can serve as a way to produce an accurate secondary and/or laboratory $CO_2$ standard gas. We hope this study helps resolve difficulties in placing a laboratory working standard onto the international isotope scales and does make accurate comparisons with other data sets from other groups.